J Antimicrob Chemother, 2001 Aug, 48(2), 231 - 4 Predominance of a methicillin-resistant Staphylococcus aureus clone susceptible to erythromycin and several other non-beta-lactam antibiotics in a Greek hospital; Polyzou A et al.; A clone of heterogeneously methicillin-resistant Staphylococcus aureus (MRSA) isolates susceptible to erythromycin, ciprofloxacin, clindamycin, co-trimoxazole, nitrofurantoin, rifampicin, tetracycline and vancomycin, predominated in a Greek hospital with a high incidence of MRSA, representing 69.1% of the total MRSA isolates . All isolates of this clone lacked the conserved genes ermA and aadD . Two subtypes of this clone were detected, the more common being resistant to aminoglycosides and carrying the bi-functional gene aacA-aphD, while an aminoglycoside-susceptible variant, lacking this gene, lost a larger SmaI macrorestriction DNA fragment and gained a smaller fragment. J Antimicrob Chemother, 2001 Aug, 48(2), 209 - 17 In vitro activity of fosfomycin in combination with various antistaphylococcal substances; Grif K et al.; Using the chequerboard technique we studied the in vitro activity of the broad spectrum antibiotic fosfomycin in combination with vancomycin, rifampicin, linezolid, quinupristin/ dalfopristin, cefazolin, meropenem and moxifloxacin against two Staphylococcus epidermidis strains (ATCC 12228, DSM 3269) and five Staphylococcus aureus isolates (ATCC 29213, DSM 683, DSM 46320, GISA 323/93, MRSA 3558/00) . The phenomena of 'trailing' and 'skipped wells' did not present a problem . Synergy was the most common effect of all drugs tested in combination with fosfomycin; only combination with vancomycin showed antagonism for two of seven isolates . Using a killing-curve technique fosfomycin showed cidal activity, where increasing the drug concentration above the MIC did not enhance killing velocity . Inhibitory concentrations of vancomycin plus fosfomycin against DSM 46320 caused effects identical to those observed with vancomycin alone . The combination of fosfomycin plus linezolid exerted the bacteriostatic effect found with linezolid alone . Fosfomycin plus quinupristin/dalfopristin exhibited the bactericidal effect found with fosfomycin alone (in contrast to the rapidly bactericidal effect of quinupristin/dalfopristin) . Electron microscopy showed that fosfomycin given in combination with linezolid, quinupristin/dalfopristin or moxifloxacin (substances that do not cause morphological alterations when given alone) resulted in 'cauliflower-shaped' distortion as caused by fosfomycin alone . Our in vitro data indicate considerable potential for fosfomycin used in combination with other antistaphylococcal antimicrobials, especially linezolid or quinupristin/dalfopristin. J Antimicrob Chemother, 2001 Aug, 48(2), 203 - 8 Short antibacterial peptides and erythromycin act synergically against Escherichia coli; Ulvatne H et al.; Five different peptides (6-18 residues) with chain lengths shorter than the required minimum to span the bacterial cell membrane as monomeric helices were designed in order to elucidate whether variation in chain length exerted differences in their mode of action . To gain a better understanding of the possible mode of action of these peptides, they were studied in combination with clinically used antibiotics with different targets . Antibiotic-peptide combinations were tested against Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 25923 . No synergy was observed between the peptides and antibiotics when tested against S . aureus . Synergic interactions between all peptides and erythromycin were observed when tested against E . coli . Synergy was also observed with rifampicin and two peptides against E . coli . There was no clear-cut correlation between the ability to interact synergically or antagonistically and the number of residues . We further investigated the combined action of our peptides and PGLa, to elucidate peptide-peptide interactions . In contrast to previously reported synergy between magainin 2 and PGLa, our peptides did not show any synergy when combined with PGLa . Thus, our results indicate an alternative mode of action of these antibacterial peptides as compared with peptides such as magainin 2. Rev Esp Cardiol, 2001 Aug, 54(8), 999 - 1001 {Infectious mitral endocarditis after radiofrequency catheter ablation of a left lateral accessory pathway}; Benito Bartolome F et al.; A 2-years-old child with Wolff-Parkinson-White syndrome associated with life-threatening symptoms underwent radiofrequency ablation of a left lateral accessory pathway . A deflectable 5F bipolar electrode catheter positioned above the atrioventricular groove by transeptal approach was used for ablation . The catheters were repeatedly used after ethylene oxide sterilisation . Although immediate post-ablation echocardiography demonstrated no complications, the patient was readmitted two days later with fever and a new mitral murmur . Penicillin-susceptible Staphylococcus aureus was isolated and intravenous antibiotics were administered . In the following weeks, the patient developed constrictive pericarditis requiring surgical treatment and acute hemiplegia caused by brain embolism arising from valvular vegetation . At 5 years of follow-up the patient presents residual hemiparesia and grade II/IV mitral insufficiency. Med J Aust, 2001 Jun 18, 174(12), 627 - 30 Non-multiresistant and multiresistant methicillin-resistant Staphylococcus aureus in community-acquired infections; Gosbell IB et al.; OBJECTIVE: To survey Staphylococcus aureus strains isolated from patients presenting from the community, comparing clinical features and antibiotic sensitivity profiles between multiresistant and non-multiresistant methicillin-resistant and methicillin-sensitive isolates . DESIGN: Retrospective case series . PARTICIPANTS AND SETTING: Patients who presented to emergency or dermatology departments in hospitals served by the South Western Sydney Area Health Service between 1 May 1998 and 30 April 1999 . All patients with methicillin-resistant S . aureus (MRSA) and the first 100 with methicillin-sensitive S . aureus were eligible . MAIN OUTCOME MEASURES: Patient demographic characteristics; risk factors; clinical presentation; treatment; outcome; and isolate antibiotic susceptibility . RESULTS: 139 patients were eligible, and 122 had clinical records available . Ten of these 122 (8%) had multiresistant MRSA, 26 (21%) non-multiresistant MRSA and 86 (70%) methicillin-sensitive S . aureus . Among patients with non-multiresistant MRSA, 29% (7/24) were born in New Zealand, Samoa or Tonga, a higher proportion than among those with multiresistant MRSA or methicillin-sensitive S . aureus (P= 0.03) . Nearly half (44%) of non-multiresistant MRSA strains were community-acquired in patients with no risk factors . Two-thirds of patients with non-multiresistant MRSA (17/26) presented with cellulitis or abscess, and 58% (11/19 evaluable patients) required surgical treatment . CONCLUSIONS: Non-multiresistant MRSA strains are common, especially among people born in New Zealand, Samoa or Tonga, and are usually community acquired . Medical practitioners should routinely swab all staphylococcal lesions for culture and sensitivity. Intern Med J, 2001 Mar, 31(2), 97 - 103 Prospective study of 424 cases of Staphylococcus aureus bacteraemia: determination of factors affecting incidence and mortality; Hill PC et al.; BACKGROUND: Staphylococcus aureus bacteraemia (SAB) is a common complication of S . aureus infection and is associated with a high mortality . AIMS: To document prospectively the pattern of illness associated with SAB in New Zealand and, by recording patient demographic factors and clinical features, to identify risk factors associated with a poor outcome . METHODS: From 1 July 1996 to 31 December 1997, adults with SAB were prospectively studied in six tertiary care hospitals . All information obtained from patients' records was recorded on worksheets and transferred to a computerized spreadsheet for analysis . RESULTS: There were 424 patients with SAB . Maori (relative risk (RR)= 1.8, 95% confidence interval (CI) = 1.3-2.6) and Pacific Island people (RR = 4.0, 95% CI = 3.1-5.3) were significantly more likely than people of European descent to acquire SAB, but not to die from the infection . Fifty per cent of cases were community acquired . A source was identified for 85%: intravenous catheter (31%), primarily hospital acquired, and skin/soft tissue (22%), primarily community acquired, were the most common foci . The 30-day mortality was 19%, 83% of whom died within 2 weeks . Risk factors for a poor outcome were: increasing age above 60, female sex (RR = 1.4, 95% CI = 1.0-2.1), diabetes mellitus (RR = 1.5, 95% CI = 1.0-2.4), immunosuppression (RR = 1.5, 95% CI = 1.0-2.4), pre-existing renal impairment (RR = 1.8, 95% CI = 1.2-2.7), malignancy (RR= 2.2, 95% CI = 1.4-3.5), lung as a source (RR = 2.8, 95% CI = 1.9-4.2) and unknown source (RR = 2.3, 95% CI = 1.5-3.3) . Mortality was also accurately predicted by two multifactor scoring systems . There was a low rate of methicillin resistance (5%) . CONCLUSIONS: Staphylococcus aureus bacteraemia is more likely to occur in certain ethnic groups, while mortality is associated with other identifiable risk factors and continues to be high . Intravenous catheters remain the most common and most preventable cause of SAB. Arch Microbiol, 2001 Jul, 176(1-2), 143 - 50 2-Oxoglutarate transport system in Staphylococcus aureus; Tynecka Z et al.; 2-{(14)C}oxoglutarate uptake in resting cells of Staphylococcus aureus 17810S occurs via two kinetically different systems: (1) a secondary, electrogenic 2-oxoglutarate:H(+) symporter (K(m)=0.105 mM), energized by an electrochemical proton potential (Delta mu H(+)) that is generated by the oxidation of endogenous amino acids and sensitive to ionophores, and (2) a Delta mu H(+)-independent facilitated diffusion system (K(m)=1.31 mM) . The 2-oxoglutarate transport system of S . aureus 17810S can be classified as a new member of the MHS (metabolite:H(+) symporter) family . This transporter takes up various dicarboxylic acids in the order of affinity: succinate = malate > fumarate > 2-oxoglutarate > glutamate . Energy conservation with 2-oxoglutarate was studied in starved cells of strain 17810S . Initial transport of 2-oxoglutarate in these cells is energized by Delta mu H(+) generated via hydrolysis of residual ATP . Subsequent oxidation of the accumulated 2-oxoglutarate generates Delta mu H(+) for further, autoenergized transport of this 2-oxoacid and also for Delta mu H(+)-linked resynthesis of ATP . In the cadmium-sensitive S . aureus 17810S, Cd(2+) accumulation strongly inhibits energy conservation with 2-oxoglutarate at the level of Delta mu H(+) generation, without direct blocking of the 2-oxoglutarate transport system or ATP synthase complex . In the cadmium-resistant S . aureus 17810R, Cd(2+) does not affect energy conservation due to its extrusion by the Cd(2+) efflux system (Cd(2+)-ATPase of P-type), which prevents Cd(2+) accumulation. Saudi Med J, 2001 Jul, 22(7), 569 - 76 Antimicrobial susceptibility testing and patterns of resistance at a tertiary care center; Akhter J et al.; Clinical microbiology laboratories are faced with the challenge of accurately detecting emerging antibiotic resistance in bacterial pathogens . In recent years, vancomycin resistant enterococci have emerged, as have penicillin resistant pneumococci and more recently, methicillin-resistant Staphylococcus aureus with reduced susceptibility to vancomycin . In order to detect these emerging resistant pathogens it is essential that antimicrobial susceptibility be carried out by laboratories as an integral part of therapeutic strategies . In this review, we discuss patterns of susceptibility of different antimicrobials as experienced at King Faisal Specialist Hospital and Research Centre, a tertiary care center in Riyadh. J Med Microbiol, 2001 Aug, 50(8), 732 - 42 Analysis of different molecular methods for typing methicillin-resistant Staphylococcus aureus isolates belonging to the Brazilian epidemic clone; Soares MJ et al.; The extensive geographic spread of MRSA isolates belonging to the Brazilian epidemic clone (BEC) limited the value of pulsed-field gel electrophoresis (PFGE) in epidemiological studies of outbreaks caused by these strains . Thus, the discriminatory power of eight different molecular methods was evaluated in an attempt to establish a methodology for genotyping BEC isolates involved in intra-hospital outbreaks . BEC isolates from five hospitals in Teresina City, Piaui State were genotyped by conventional electrophoresis or PFGE of Cla I- or Sma I-digested genomic DNA hybridised with specific labelled mecA, Tn554, IS257 and IS256 probes . The combination of PFGE with Cla I/mecA, Cla I/Tn554, Cla I/IS257, Sma I/mecA and Sma I/IS257 probe-fingerprinting techniques provided a very poor discriminatory power for BEC strains . Although Cla I/IS256 fingerprinting discriminated 17 different polymorphisms among the isolates displaying PFGE A1 pattern, this strategy was not reproducible . In contrast, the combination of PFGE and Sma I/IS256 polymorphisms differentiated BEC isolates into nine stable polymorphisms . Thus combination of PFGE and hybridisation with IS256 probe may be recommended as a useful means of typing BEC strains involved in intra-hospital infections. Mol Pathol, 2001 Aug, 54(4), 244 - 7 Identification of slide coagulase positive, tube coagulase negative Staphylococcus aureus by 16S ribosomal RNA gene sequencing; Woo PC et al.; AIMS: To ascertain the clinical importance of a strain of slide coagulase positive but tube coagulase negative Staphylococcus species isolated from the blood culture of a 43 year old patient with refractory anaemia with excessive blasts in transformation who had neutropenic fever . METHODS: The isolate was investigated phenotypically by standard biochemical methods using conventional biochemical tests and two commercially available systems, the Vitek (GPI) and API (Staph) systems . Genotypically, the 16S ribosomal RNA (rRNA) gene of the bacteria was amplified by the polymerase chain reaction (PCR) and sequenced . The sequence of the PCR product was compared with known 16S rRNA gene sequences in the GenBank by multiple sequence alignment . RESULTS: Conventional biochemical tests did not reveal a pattern resembling a known Staphylococcus species . The Vitek system (GPI) showed that it was 94% S . simulans and 3% S . haemolyticus, whereas the API system (Staph) showed that it was 86.8% S . aureus and 5.1% S . warneri . 16S rRNA gene sequencing showed that there was a 0 base difference between the isolate and S . aureus, 28 base difference between the isolate and S . lugdunensis, 39 base difference between the isolate and S . schleiferi, 21 base difference between the isolate and S . haemolyticus, 41 base difference between the isolate and S . simulans, and 23 base difference between the isolate and S . warneri, indicating that the isolate was a strain of S . aureus . Vancomycin was subsequently prescribed and blood cultures taken four days after the start of treatment were negative . CONCLUSIONS: 16S rRNA gene sequencing was useful in ascertaining the clinical importance of the strain of slide coagulase positive but tube coagulase negative Staphylococcus species isolated from blood culture and allowing appropriate management. Lancet, 2001 Jul 21, 358(9277), 207 - 8 Linezolid resistance in a clinical isolate of Staphylococcus aureus; Tsiodras S et al.; The new oxazolidinone antimicrobial, linezolid, has been approved for the treatment of infections caused by various gram-positive bacteria, including meticillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE) . Although instances of linezolid resistance in VRE have been reported, resistance has not been encountered among clinical isolates of S aureus . We have characterised an MRSA isolate resistant to linezolid that was recovered from a patient treated with this agent for dialysis-associated peritonitis. Eur J Clin Microbiol Infect Dis, 2001 Jun, 20(6), 425 - 7 Antibiotic susceptibility and phage typing of methicillin-resistant and -sensitive Staphylococcus aureus clinical isolates at three periods during 1991-1997; Samra Z et al.; The aim of the study presented here was to evaluate the antibiotic susceptibility of Staphylococcus aureus over a 7-year period . A total of 2,122 clinical isolates of Staphylococcus aureus were collected from hospitalized patients at 3-year intervals during the period 1991-1997 . The prevalence of methicillin-resistant isolates was 41.6%, 38.2% and 36% in 1991, 1994 and 1997, respectively; all of these isolates were sensitive to vancomycin . Over the study period, resistance to pristinamycin and fusidic acid increased slightly and resistance to imipenem, rifampicin and amikacin increased greatly, while resistance to trimethoprim/sulfamethoxazole decreased . For methicillin-sensitive Staphylococcus aureus isolates, significantly increased resistance was observed against amikacin only . Phage typing was conducted using the international set of phages . All of the isolates that were sensitive to group I, group II, or group V phages were sensitive to methicillin . Of the isolates that were sensitive to group III phages, 96% were methicillin resistant, and 70.5% of them were sensitive to phages 75 and 85. Eur J Clin Microbiol Infect Dis, 2001 Jun, 20(6), 402 - 6 Immunorestitution diseases in patients not infected with HIV; Cheng VC et al.; The aim of this study was to assess the clinical spectrum of immunorestitution disease (IRD) in hospitalized patients over a 12-month period . In nine of 18 patients who presented with clinical deterioration during reduction or cessation of immunosuppressants (n = 6) or bone marrow engraftment (n = 3), IRD cases included the following infections: scabies infestation (n = 1); gastric strongyloidiasis (n = 1); hepatosplenic candidiasis (n = 1); methicillin-resistant Staphylococcus aureus abscess formation (n = 2); polyomavirus-related hemorrhagic cystitis (n = 3); and influenza A pneumonitis (n = 1) . Immunopathological damage during withdrawal of immunosuppression is an incidental way to uncover an asymptomatic infectious disease . Serial monitoring of hematological and clinical profiles is essential in making a diagnosis of IRD. Eur J Clin Microbiol Infect Dis, 2001 Jun, 20(6), 380 - 4 Long-term infectious complications and their relation to treatment duration in catheter-related Staphylococcus aureus bacteremia; Zeylemaker MM et al.; The optimal duration of treatment for catheter-related Staphylococcus aureus bacteremia is not known . Short courses (< or = 2 weeks) of therapy should be viewed with caution because essential data on late complications, such as osteomyelitis and metastatic abscesses, are lacking . This study represents a retrospective analysis of the data from 49 adult patients hospitalised in the period 1994-1996 (mean age, 57 years; range, 20-90 years; 47% male) and from whom Staphylococcus aureus was cultured concomitantly from peripheral blood and catheter segments . Forty-six venous catheters, two arterial catheters, and one unknown type of catheter were used . Forty-four patients were treated with effective anti-Staphylococcus aureus antibiotics . Twenty patients had a favourable outcome, defined as no complication and no death during 1 year of follow-up, 24 patients had complications, 14 patients died due to attributable mortality, and 5 other patients died of an underlying disease without showing signs or symptoms of a complication . Patients were categorised according to the duration of treatment . There were small differences between a shorter (1-14 days) and a longer (>14 days) course of antibiotics with regard to favourable outcome (41% vs . 33%), complications (48% vs . 53%), attributable death (31% vs . 20%), and death due to underlying disease (41% vs . 33%), respectively . The rates of complications and death were high, but a definite conclusion cannot be drawn because the study was underpowered . More randomised trials are needed, but, until the results of such trials are available, the duration of therapy should not be shortened to less than 14 days. Tidsskr Nor Laegeforen, 2001 Jan 20, 121(2), 204 - 8 {Infection outbreaks caused by methicillin-resistant Staphylococcus aureus at Haukeland hospital}; Bo K et al.; BACKGROUND: Nosocomial infections caused by methicillin-resistant Staphylococcus aureus (MRSA) represent an increasing problem worldwide . MATERIAL AND METHODS: We report two outbreaks of methicillin-resistant S . aureus at Haukeland University Hospital during 1998-99 . RESULTS: During the fall of 1998, four patients in the dermatological ward and three of their relatives were infected or colonised with MRSA . The strain was probably introduced by an eczematous patient who had recently arrived from Japan . Three patients became chronic carriers . The second outbreak involved three other hospital departments in July-August 1999 . The index patient, a multitraumatised japanese tourist, died 16 days after admission . Two other patients were infected, one of them became a chronic carrier . According to official guidelines, neither of the index patients needed MRSA screening . Pulsed field gel-electrophoresis of the MRSA isolates revealed two different strains at the first outbreak, both probably introduced from the index patient, and one single strain at the second outbreak . Nasal swabs of staff were negative . INTERPRETATION: Physicians need to know that recommended guidelines regarding MRSA screening do not cover all types of risk situations . MRSA carriage among healthcare workers is probably not an important source of MRSA spread in hospitals . Measures to prevent cross infection between patients should be emphasised. J Clin Microbiol, 2001 Aug, 39(8), 2760 - 7 Genetic variation among hospital isolates of methicillin-sensitive Staphylococcus aureus: evidence for horizontal transfer of virulence genes; Moore PC et al.; Staphylococcus aureus strains often carry in their genomes virulence genes that are not found in all strains and that may be carried on discrete genetic elements . Strains also differ in that they carry one of four classes of an accessory gene regulator (agr) locus, an operon that regulates virulence factor expression and that has been proposed to be a therapeutic target . To look at their distribution among hospital strains, we investigated 38 methicillin-sensitive S . aureus isolates, classifying the isolates by agr class and screening them for the presence and restriction fragment length polymorphisms (RFLPs) of 12 core and 14 accessory virulence genes . Twenty-three (61%) were agr class I, 10 (26%) were agr class II, and 5 (13%) were agr class III . None were agr class IV . The S . aureus strains had distinguishable RFLP profiles, although clusters of isolates with clearly related core gene profiles were found among our strains, including all five agr class III strains, two sets of six strains within agr class I, and six strains within agr class II . Within these clusters there was evidence of horizontal acquisition and/or loss of multiple accessory virulence genes . Furthermore, two isolates from the same patient were identical except for the presence of the sea gene, indicating that movement of mobile elements may occur in vivo . Several strong correlations with the carriage of virulence genes between strains were seen, including a positive correlation between tst and agr class III and negative correlations between tst and lukE-splB and between lukE-splB and seg-sei . This suggests that the core genome or the presence of accessory genetic elements within a strain may influence acquisition and loss of other elements encoding virulence genes. J Nat Prod, 2001 Jul, 64(7), 976 - 9 Isolation and bioactivities of constitutents of the roots of Garcinia atroviridis; Permana D et al.; Two new prenylated compounds, the benzoquinone atrovirinone (1) and the depsidone atrovirisidone (2), were isolated from the roots of Garcinia atroviridis . Their structures were determined on the basis of the analysis of spectroscopic data . While compound 2 showed some cytotoxicity against HeLa cells, both compounds 1 and 2 were only mildly inhibitory toward Bacillus cereus and Staphylococcus aureus. Nature, 2001 Jul 26, 412(6845), 452 - 5 Antibacterial agents based on the cyclic D,L-alpha-peptide architecture; Fernandez-Lopez S et al.; The rapid emergence of bacterial infections that are resistant to many drugs underscores the need for new therapeutic agents . Here we report that six- and eight-residue cyclic d,l-alpha-peptides act preferentially on Gram-positive and/or Gram-negative bacterial membranes compared to mammalian cells, increase membrane permeability, collapse transmembrane ion potentials, and cause rapid cell death . The effectiveness of this class of materials as selective antibacterial agents is highlighted by the high efficacy observed against lethal methicillin-resistant Staphylococcus aureus infections in mice . Cyclic d,l-alpha-peptides are proteolytically stable, easy to synthesize, and can be derived from a potentially vast membrane-active sequence space . The unique abiotic structure of the cyclic peptides and their quick bactericidal action may also contribute to limit temporal acquirement of drug resistant bacteria . The low molecular weight d,l-alpha-peptides offer an attractive complement to the current arsenal of naturally derived antibiotics, and hold considerable potential in combating a variety of existing and emerging infectious diseases. J Vet Med B Infect Dis Vet Public Health, 2001 Jun, 48(5), 373 - 83 Dynamics of Staphylococcus aureus infections during vaccination with an autogenous bacterin in dairy cattle; Hoedemaker M et al.; The effect of an autogenous vaccine against Staphylococcus aureus on S . aureus prevalence and mastitis, as well as on somatic cell count (SCC), was studied in a dairy herd with a high prevalence of S . aureus . The vaccination group (n = 35; 22 cows and 13 heifers) and the control group (n = 36; 23 cows and 13 heifers) received the vaccine or a placebo, respectively, according to the following protocol: all animals: basic immunization (twice, 3 weeks apart); cows: booster dose at the time of drying off, 5 and 2 weeks before calculated calving date; heifers: booster dose 2 and 5 weeks before calculated calving date . The vaccine or the placebo was administered subcutaneously in the area of the supramammary lymph nodes . Quarter milk samples were collected monthly and subjected to SCC and bacteriological evaluation . At this time, the animals were also checked for signs of clinical mastitis . Non-clinical S . aureus mastitis diagnoses were based on udder quarter SCC and a positive S . aureus culture . In order to compare the SCC in individual whole milk samples, records from the monthly milk quality testing were evaluated . Cow and udder quarter prevalence of S . aureus intramammary infections calculated for the experimental animals and quarters, respectively, did not differ between groups . However, during the lactation period following the boostcr dose, the prevalence of S . aureus increased in both groups (P < 0.05) . The cumulative incidence of various mastitis diagnoses (clinical, subclinical, latent infection) due to S . aureus on an animal basis did not differ between groups . On an udder quarter basis, the cumulative incidence of subclinical mastitis was higher in vaccinated animals than in control animals (33.8 versus 26.0%; P < 0.05) . This was mainly due to a higher cumulative incidence of subclinical mastitis in vaccinated than control heifers . The SCC in composite milk samples did not differ between groups, but increased as lactation progressed . The herd prevalence of S . aureus differed considerably throughout the study period, but declined consistently to below 10% at the end of the study period . Recent herd checks revealed a prevalence of S aureus infections of < 5% . It is concluded that the autogenous bacterin tested in this study did not have the desired effect on the prevalence of S . aureus infections and mastitis or SCC . The decline in S . aureus prevalence was very probably due to other factors than specific immunization against S . aureus. Drug Ther Bull, 2001 Jul, 39(7), 54 - 6 Linezolid for gram-positive infections; Structural rationale for the modulation of abscess formation by Staphylococcus aureus capsular polysaccharides; Channing Laboratory, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA . atzianabos@channing.harvard.edu Staphylococcus aureus is a medically important bacterial pathogen that is a common cause of superficial and deep-seated abscesses in humans . Most S . aureus isolates produce either a serotype 5 or 8 capsular polysaccharide (CP) that has been shown to enhance bacterial virulence . We investigated the role of S . aureus CPs in modulating abscess formation in an experimental animal model of intraabdominal infection . Structural studies of CP8 revealed that it has a zwitterionic charge motif conferred by the negatively charged carboxyl group of N-acetylmannosaminuronic acid and free amino groups available on partially N-acetylated fucosamine residues . We report that purified CP5 and CP8 facilitated intraabdominal abscess formation in animals when given i.p . with a sterile cecal contents adjuvant . Chemical modifications that neutralized the positively or negatively charged groups on CP8 abrogated its ability to provoke abscesses . Rats prophylactically treated with CP8 s.c . were protected against abscess formation induced by homologous or heterologous zwitterionic polysaccharides . Likewise, treatment with CP8 protected against challenge with viable S . aureus strains PS80 (a capsule type 8 strain) or COL (a methicillin-resistant capsule type 5 strain) . Purified CP8 was a potent activator of rat and human CD4(+) T cells in vitro . When transferred to naive rats, these activated T cells modulated the development of intraabdominal abscess formation . These results provide a structure/function rationale for abscess formation by S . aureus and expand the sphere of encapsulated organisms that interact directly with T cells to regulate this host response to bacterial infection. J Surg Res, 2001 Aug, 99(2), 316 - 20 Prophylaxis against Staphylococcus aureus vascular graft infection with mupirocin-soaked, collagen-sealed dacron; Ghiselli R et al.; A rat model was used to investigate the efficacy of mupirocin in the prevention of vascular prosthetic graft infections . The effect of mupirocin-soaked Dacron was compared with the effect of rifampin-soaked, collagen-sealed Dacron in the rat model of graft infection caused by methicillin-susceptible Staphylococcus aureus and methicillin-resistant S . aureus . Graft infections were established in the back subcutaneous tissue of 195 adult male Wistar rats by implantation of 1-cm(2) Dacron prostheses followed by topical inoculation with 5 x 10(7) colony-forming units of S . aureus . The study included a control group (no graft contamination), two contaminated groups that did not receive any antibiotic prophylaxis, two contaminated groups in which perioperative intraperitoneal amoxicillin clavulanate prophylaxis (50 mg/kg) was administered, four contaminated groups that received mupirocin- or rifampin-soaked graft, and four contaminated groups that received mupirocin- or rifampin-soaked graft and perioperative intraperitoneal amoxicillin clavulanate prophylaxis (50 mg/kg) . The grafts were sterilely removed 7 days after implantation and the infection was evaluated by using sonication and quantitative agar culture . Data analysis showed that the efficacy of mupirocin against both strains was significantly different from that of the untreated control . In addition, mupirocin was more effective than rifampin against the methicillin-resistant strain . Finally, only the combination of mupirocin and amoxicillin clavulanate produced complete suppression of growth of all strains . CMAJ, 2001 Jul 10, 165(1), 21 - 6 The evolution of methicillin-resistant Staphylococcus aureus in Canadian hospitals: 5 years of national surveillance; Simor AE et al.; BACKGROUND: To better understand the epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) in Canadian hospitals, surveillance has been conducted in sentinel hospitals across the country since 1995 . We report the results of the first 5 years of the program . METHODS: For each newly identified inpatient with MRSA, medical records were reviewed for demographic and clinical data . Isolates were subjected to susceptibility testing and molecular typing by pulsed-field gel electrophoresis . RESULTS: A total of 4507 patients infected or colonized with MRSA were identified between January 1995 and December 1999 . The rate of MRSA increased each year from a mean of 0.95 per 100 S . aureus isolates in 1995 to 5.97 per 100 isolates in 1999 (0.46 per 1000 admissions in 1995 to 4.12 per 1000 admissions in 1999) (p < 0.05) . Most of the increase in MRSA occurred in Ontario, Quebec and the western provinces . Of the 3009 cases for which the site of MRSA acquisition could be determined, 86% were acquired in a hospital, 8% were acquired in a long-term care facility and 6% were acquired in the community . A total of 1603 patients (36%) were infected with MRSA . The most common sites of infection were skin or soft tissue (25% of MRSA infections), pulmonary tissues (24%) and surgical sites (23%); 13% of the patients were bacteremic . An epidemiologic link with a previously identified MRSA patient was suspected in 53% of the cases . Molecular typing indicated that most (81%) of the isolates could be classified as related to 1 of the 4 Canadian epidemic strains of MRSA . INTERPRETATION: There has been a significant increase in the rate of isolating MRSA in many Canadian hospitals, related to the transmission of a relatively small number of MRSA strains. Biochemistry, 2001 Jul 31, 40(30), 8877 - 86 Vgb from Staphylococcus aureus inactivates streptogramin B antibiotics by an elimination mechanism not hydrolysis; Mukhtar TA et al.; The streptogramin antibiotics were identified almost 50 years ago but have only recently found clinical use as a consequence of the increase in multidrug-resistant bacteria . Despite the fact that these antibiotics have historically not found intense clinical use, resistance to streptogramins exists . Streptogramins consist of a mixture of two components: cyclic polyunsaturated macrolactones (group A) and cyclic hexadepsipeptides (group B) . The latter are cyclized through an ester bond between the hydroxyl group of an N-terminal threonine and the C-terminal carboxyl . Resistance to the B streptogramins can occur through the production of enzymes such as Vgb from Staphylococcus aureus . This enzyme had been assumed to be a lactonase that inactivates the cyclic antibiotic by linearization through hydrolytic cleavage of the ester bond . We have expressed recombinant Vgb in quantity and, using a combination of mass spectrometry, NMR, and synthesis of model depsipeptides, show unequivocally that streptogramin B inactivation does not involve hydrolysis of the ester bond . Rather, the hexadepsipeptide is linearized through an elimination reaction across the ester bond generating an N-terminal dehydrobutyrine group . Therefore, Vgb is not a hydrolase but a lyase . We also have explored the activity of Vgb orthologues present in the chromosomes of various bacteria including Bordetella pertussis and Streptomyces coelicolor and have determined that these enzymes also show streptogramin B inactivation through an elimination mechanism indistinguishable to that used by Vgb . These results demonstrate that Vgb is a member of a large group of streptogramin B lyases that are present not only in resistant clinical isolates but also in the chromosomes of many bacteria . There is therefore a significant reservoir of streptogramin resistance enzymes in the environment, which has the potential to impact the long-term utility of these antibiotics . This research establishing the molecular mechanism of streptogramin resistance therefore has the potential to be exploited in the discovery of inhibitory compounds that could rescue antibiotic activity even in the presence of resistance elements. Epidemiol Infect, 2001 Jun, 126(3), 445 - 52 Genotypic analysis of Staphylococcus aureus from milk of dairy cows with mastitis in Argentina; Buzzola FR et al.; Staphylococcus aureus is the most prevalent pathogen causing mastitis of dairy ruminants . This study was developed to ascertain the genotypes and genealogical relationship among strains isolated from milk of bovines with mastitis in Argentina . Molecular epidemiological analysis of S . aureus was performed on 112 isolates from 21 districts . Clonality was assessed by SmaI pulsed-field gel electrophoresis (PFGE) typing, automated EcoRI ribotyping and restriction enzyme analysis of plasmid (REAP) DNA profiles . A total of 22 band patterns distributed in four clusters were found by SmaI PFGE analysis . The similarity of clusters 2, 3 and 4 with cluster 1 was 0.73, 0.69 and 0.33, respectively, and 101 of 112 isolates belonged in cluster 1 . PFGE band patterns from 42 isolates within cluster I were indistinguishable from each other (type A) . The second largest group of isolates with indistinguishable PFGE band patterns was subtype A11, which was composed of 19 isolates . Automated ribotyping assigned the 112 isolates into 13 ribotypes . Among these, the most prevalent ribotypes I and VI were composed of 49 and 35 isolates respectively . Although there was certain correspondence between PFGE genotypes and ribotypes, further discrimination was achieved by combining both methods . REAP DNA profile analysis was useful to provide even further discrimination between isolates with identical PFGE genotype and ribotype . The most prevalent S . aureus strains A/I and A11/VI were widely distributed in the country and were not restricted to individual nearby locations . Prevalence of these two strains varied consecutively within a period of 8 years . Whether the shift in type prevalence was due to selection of a phenotypic trait remains undisclosed. Epidemiol Infect, 2001 Jun, 126(3), 351 - 6 Methicillin-resistant Staphylococcus aureus (MRSA): a community-based prevalence survey; Abudu L et al.; A prevalence survey of nasal methicillin-resistant Staphylococcus aureus (MRSA) carriage was undertaken on a random sample of adults (aged over 16) resident in the community in Birmingham, UK during 1998 . Microbiological samples were taken from the anterior nares at the subjects' general practice or in their home . Information about risk factors for the acquisition of MRSA was obtained via a self-completed questionnaire . A 58% response rate (280/483) was achieved . The prevalence of nasal MRSA colonization was 1.5% {4/274, 95% confidence interval (CI) 0.03-2.9%} . Twenty-three per cent (63/274) of subjects were nasal carriers of S . aureus . Six per cent (4/63) of S . aureus isolates were MRSA and 2 of the 4 MRSA carriers reported previous contact with health facilities . The prevalence of MRSA colonization in the general adult population in Birmingham appears to be low. Clin Exp Med, 2001 Mar, 1(1), 35 - 41 The acute phase response following implantation of triclosan-bonded vascular prostheses; Hernandez-Richter TM et al.; OBJECTIVE: Infection of prosthetic material is a major complication of vascular surgery . Therapy for it includes implantation of antimicrobial prostheses bonded with different antimicrobial agents . These agents may, however, induce an acute phase reaction following implantation in the host, thus compromising follow-up of the infection . It is not known whether the antimicrobial agent triclosan induces a significant acute phase reaction when bonded to vascular prostheses . METHODS: To study this, 34 adult swine weighing 20-30 kg were allotted randomly to the following groups: (1) controls with untreated prostheses, (2) control group with triclosan-bonded prostheses, (3) therapy group with untreated prostheses, local infection with Staphylococcus aureus surgical revision, and exchange with new, untreated prostheses, and (4) therapy group with untreated prostheses, local infection with S . aureus, surgical revision, and exchange with triclosan-bonded prostheses . Serum C-reactive protein (CRP) and haptoglobin values were determined during the 28-day period after surgery . The study was performed at the Institute for Surgical Research of the Ludwig Maximilian University School of Medicine in Munich . RESULTS: Normal ranges of serum CRP and haptoglobin values were 10.7+/-1.4 microg/ml and 2.5+/-0.3 mg/ml, respectively . Following implantation of untreated and triclosan-bonded vascular prostheses, significantly elevated serum CRP and haptoglobin values were observed . No significant differences between results with triclosan-bonded and untreated prostheses were observed in control or treatment groups . No correlation was found between acute phase reaction and the absence or presence of infection . CONCLUSIONS: Triclosan is the only antimicrobial agent that bonds to vascular prosthetic material without the need of a sealant . Our data indicate that vascular prosthesis implantation, whether untreated and triclosan-bonded, results in a significant acute phase reaction . No differences between antimicrobial and untreated prostheses were observed, independently of the absence or presence of infection . The antimicrobial agent itself did not induce a severe acute phase response and may, therefore, be used in patients at risk of infection. J Bacteriol, 2001 Aug, 183(16), 4779 - 85 Identification and characterization of a monofunctional glycosyltransferase from Staphylococcus aureus; Wang QM et al.; A gene (mgt) encoding a monofunctional glycosyltransferase (MGT) from Staphylococcus aureus has been identified . This first reported gram-positive MGT shared significant homology with several MGTs from gram-negative bacteria and the N-terminal glycosyltransferase domain of class A high-molecular-mass penicillin-binding proteins from different species . S . aureus MGT contained an N-terminal hydrophobic domain perhaps involved with membrane association . It was expressed in Escherichia coli cells as a truncated protein lacking the hydrophobic domain and purified to homogeneity . Analysis by circular dichroism revealed that secondary structural elements of purified truncated S . aureus MGT were consistent with predicted structural elements, indicating that the protein might exhibit the expected folding . In addition, purified S . aureus MGT catalyzed incorporation of UDP-N-acetylglucosamine into peptidoglycan, proving that it was enzymatically active . MGT activity was inhibited by moenomycin A, and the reaction product was sensitive to lysozyme treatment . Moreover, a protein matching the calculated molecular weight of S . aureus MGT was identified from an S . aureus cell lysate using antibodies developed against purified MGT . Taken together, our results suggest that this enzyme is natively present in S . aureus cells and that it may play a role in bacterial cell wall biosynthesis. Int J Antimicrob Agents, 2001 Jul, 18(1), 61 - 5 Methicillin-resistant Staphylococcus aureus in the hospitals of central Greece; Petinaki E et al.; A total of 250 consecutive Staphylococcus aureus clinical isolates were collected during the period 1999-2000 from the five major hospitals of the district of Thessaly (Central Greece) . Thirty seven (14.8%) of the isolates were mecA-positive (MRSA) in a PCR-based assay; all exhibited resistance to oxacillin (agar dilution MICs > or =4 mg/L) and were also resistant to multiple antibiotics . Most of the MRSA isolates had been collected in the intensive care units and the surgical wards of the participating hospitals in a sporadic fashion . The MRSA incidence found here was significantly lower than reported in previous studies from Greece . Molecular typing by PFGE showed that the MRSA isolates were distributed between three pulsotypes . Evaluation of various conventional methods for assessing methicillin resistance showed that oxacillin agar dilution and immunological detection of PBP2a with the Slidex MRSA Detection kit were the most reliable in this setting . Misclassifications of isolates exhibiting low-level resistance (oxacillin MIC 2-4 mg/L) occurred with the salt agar screen, the oxacillin disk diffusion and the ATB Staph System methods. Am J Trop Med Hyg, 2001 May-Jun, 64(5-6), 298 - 302 Pathogenic aspects of pyogenic liver abscess associated with experimental schistosomiasis; Teixeira R et al.; Schistosomiasis mansoni infection that occurs concurrently with Staphylococcus aureus bacteremia favors the formation of pyogenic liver abscess . The present experimental study in mice evaluated the following aspects of the relationship between infection with Schistosoma mansoni and liver abscess caused by S . aureus: a) the role of the eggs of S . mansoni in the genesis of the abscesses; b) the influence of different phases of schistosomiasis in the development of liver abscesses; and c) the effect of the treatment of schistosomiasis on the development of the abscesses . Macroscopic and histopathological study showed multiple liver abscesses around granulomas of S . mansoni in the acute and chronic phases of schistosomiasis . Treatment of acute schistosomiasis before experimentally-induced bacteremia did not prevent the formation of liver abscess . The study findings indicate that granulomas around S . mansoni eggs and worms lodged in the liver provide a focus and substrate for pyogenic abscesses caused by S . aureus. Spine, 2001 Jul 15, 26(14), 1570 - 6 Hematogenous pyogenic facet joint infection; Muffoletto AJ et al.; STUDY DESIGN: Retrospective . OBJECTIVES: To determine the incidence, clinical presentation, diagnostic laboratory values, imaging characteristics, and optimal treatment of hematogenous pyogenic facet joint infections . SUMMARY OF BACKGROUND DATA: There are 27 documented cases of hematogenous pyogenic facet joint infections . Data regarding incidence, clinical presentation, diagnosis, and treatment response are incomplete because of the paucity of reported cases . METHODS: This is a retrospective study of all cases of hematogenous pyogenic facet joint infection treated at one institution . Data from previous publications were combined with the present series to identify pertinent clinical characteristics and response to treatment . RESULTS: A total of six cases (4%) of hematogenous pyogenic facet joint infection were identified of 140 cases of hematogenous pyogenic spinal infection at our institution . Combining all reported cases reveals the following: The average patient age is 55 years . Ninety-seven percent of cases occur in the lumbar spine . Epidural abscess formation complicates 25% of the cases of which 38% develop severe neurologic deficit . Erythrocyte sedimentation rate and C-reactive protein are elevated in all cases . Staphylococcus aureus is the most common infecting organism . Magnetic resonance imaging is accurate in identifying the septic joint and associated abscess formation . Percutaneous drainage of the involved joint has a higher rate of success (85%) than treatment with antibiotics alone (71%), but the difference is not significant (P = 0.37) . CONCLUSIONS: Hematogenous pyogenic facet joint infection is a rare but underdiagnosed clinical entity . Facet joint infections may be complicated by abscess formation in the epidural space or in the paraspinal muscles . Uncomplicated cases treated with percutaneous drainage and antibiotics may fare better than those treated with antibiotics alone . Cases complicated by an epidural abscess and severe neurologic deficit should undergo immediate decompressive laminectomy. J Hosp Infect, 2001 Aug, 48(4), 308 - 11 The usefulness of masks in preventing transient carriage of epidemic methicillin-resistant Staphylococcus aureus by healthcare workers; Lacey S et al.; We assessed the usefulness of wearing masks in preventing epidemic methicillin-resistant Staphylococcus aureus (EMRSA) carriage in nursing and physiotherapy staff on two dedicated EMRSA units . In the first phase of the study, members of staff were screened for EMRSA carriage immediately before and after periods of duty using nose, throat and hand swabs . During the second phase of the study, masks were worn by staff carrying out procedures associated with significant EMRSA exposure and examined for EMRSA as described for the first phase . Both phases were conducted over a period of two months . Forty-eight percent of nursing staff were colonized with EMRSA at some time during the first phase of the study . Wearing masks significantly reduced nasal, throat and hand carriage of EMRSA (P= 0.05) . We conclude that the wearing of masks by healthcare workers performing certain activities for EMRSA positive patients may prevent transient colonization and hence may be a useful intervention in the control of EMRSA in the hospital environment . J Hosp Infect, 2001 Aug, 48(4), 275 - 80 Patients' perceptions of methicillin-resistant Staphylococcus aureus and source isolation: a qualitative analysis of source-isolated patients; Newton JT et al.; A group of 19 individuals who had been infected with methicillin-resistant Staphylococcus aureus (MRSA) and placed in source isolation were interviewed about their views of MRSA infection and the experience of source isolation . Participants were unclear about the nature of MRSA, and generally did not perceive the infection to have a significant impact upon their life (either in terms of the presence of symptoms or in restriction of activities) . Despite this, roughly half the sample thought that an MRSA infection was 'serious' . Only one participant clearly viewed their MRSA as hospital-acquired, most being uncertain about the mode of transmission or viewing it as unrelated to the behaviour of care staff . Few respondents displayed an accurate knowledge of the reasons for source isolation and barrier nursing . Isolation was viewed as having advantages and disadvantages . There was little evidence of a detrimental psychological effect of isolation . Patients infected with MRSA appear to understand little about their condition or the necessity for barrier nursing and source isolation . This has implications for understanding patients' adherence with infection control procedures . Rev Soc Bras Med Trop, 2001 May-Jun, 34(3), 233 - 7 {Evaluation of secondary bacterial infection's influence on the course of cutaneous leishmaniasis in Corte de Pedra, Bahia}; Vera LA et al.; In order to study the prevalence of secondary bacterial infection in ulcerated lesions and its relationship to the healing process, 84 leishmaniotic patients were evaluated . Diagnosis of the secondary infection was made by bacterial aerobic culture of peripheral tissue specimen of the ulcer . All patients received antimonial therapy during 20 days and washed their ulcers with common soap . Cases were composed mainly of adolescent and adult farmer patients with single lesions . The evaluated ulcers were encountered on legs and feet in 47.6% . Secondary bacterial infection was found in 45/83 (54.2%), and was more frequent in lesions located below the knee . Staphylococcus aureus predominated (89%) . The ulcers' healing process, evaluated in 79 patients one month after finishing treatment, was not influenced by the secondary bacterial infection. Neurol Med Chir (Tokyo), 2001 Jun, 41(6), 325 - 9 Two-staged operation for thoracolumbar osteomyelitis following methicillin-resistant staphylococcus aureus infection of a craniectomy wound--case report; Yamada T et al.; A previously healthy 53-year-old woman developed pyogenic vertebral osteomyelitis (PVO) manifesting as progressive lumbago following wound infection of a decompressive craniectomy performed for brain contusion caused by a traffic accident . Magnetic resonance imaging disclosed vertebral osteomyelitis at T-12 and L-1 with paravertebral abscess . Anterior debridement and fusion using autografts were performed at the first operation . Methicillin-resistant Staphylococcus aureus (MRSA) was cultured from the abscess specimen . Antibiotic therapy resolved the infection . Pedicle screw fixation was performed at the second operation . The patient became free from back pain and no recurrence of infection was seen . The diagnosis of PVO is frequently observed or delayed because of the nonspecific symptomatic presentation in the early stage . Coexistent infection or trauma makes early diagnosis more difficult . Indications and timing of instrumentation for the spinal column infected with MRSA is difficult . Two-staged operation with anterior debridement and posterior instrumentation after eradication of the infection is a safe and effective procedure for MRSA vertebral osteomyelitis. Biochemistry, 2001 Jul 24, 40(29), 8514 - 22 The staphylococcal leukocidin bicomponent toxin forms large ionic channels; Miles G et al.; The genes encoding the F and S components of a leukocidin, LukF (HlgB) and LukS (HlgC), a pore-forming binary toxin, were amplified from the Smith 5R strain of Staphylococcus aureus both with and without sequences encoding 3'-hexahistidine tags . The His-tagged components were expressed in Escherichia coli and purified under nondenaturing conditions . In addition, the two unmodified proteins and the His-tagged versions were produced in an E . coli cell-free in vitro transcription and translation system . An SDS-stable oligomer of approximately 200 kDa appeared when both components were cotranslated in the presence of rabbit erythrocyte membranes . Hemolytic activity of the combined components against rabbit erythrocytes was measured for both in vitro- and in vivo-produced polypeptides, yielding similar HC(50) values of approximately 0.14 microg/mL . The pore-forming properties of the recombinant leukocidin were also investigated with planar lipid bilayers of diphytanoylphosphatidylcholine . Although leukocidins and staphylococcal alpha-hemolysin share partial sequence identity and related folds, LukF and LukS produce a pore with a unitary conductance of 2.5 nS {1 M KCl and 5 mM HEPES (pH 7.4)}, which is more than 3 times greater than that of alpha-hemolysin measured under the same conditions . Therefore, if the leukocidin pore were a cylinder, its diameter would be almost twice that of alpha-hemolysin . In addition, the leukocidin pore is weakly cation selective and exhibits gating at low positive potentials, while alpha-hemolysin is weakly anion selective and gates only at high potentials . Taken together, these data suggest that the structure of the oligomeric pore formed by the leukocidin examined here has diverged significantly from that of alpha-hemolysin. Biomaterials, 2001 Aug, 22(16), 2239 - 46 Synthesis and characterization of non-leaching biocidal polyurethanes; Grapski JA et al.; The biocidal activities of a series of quaternized polyurethanes were examined against Staphylococcus aureus and Escherichia coli . The percentage of dead cells on a surface was found to depend on the alkyl halide used for quaternization, the concentration of quaternized moieties in the polyurethane, the gram-type of the microorganism, and the contact time of the organism with the surface . N,N-bis(2-hydroxyethyl)isonicotinamide (BIN) was incorporated as the chain extender in a series of poly(tetramethylene oxide)-based polyurethane block copolymers . Three families of materials were synthesized that contained increasing hard segment fractions and therefore increasing concentrations of BIN . The pyridine ring in BIN was quaternized with a variety of alkyl halides to form cationic polyurethanes that possessed biocidal activity . The effect of quaternization on material properties was examined with tensile testing, water absorption analysis, and contact angle measurements . The antibacterial action of the polymers was investigated with zone of inhibition experiments and fluorescence microscopy, which was established as a reliable technique to determine the viability of organisms attached to a polymer surface. Mol Microbiol, 2001 Jul, 41(1), 247 - 61 The two-component system ArlS-ArlR is a regulator of virulence gene expression in Staphylococcus aureus; Fournier B et al.; Staphylococcus aureus is a major human pathogen that produces many virulence factors in a temporally regulated manner controlled by at least two global virulence regulatory loci (agr and sarA) . We identified previously a two-component system, ArlS-ArlR, that modifies the activity of extracellular serine protease and may be involved in virulence regulation . Here, we show that mutations in either arlR or arlS increase the production of secreted proteins {alpha-toxin (Hla), beta-haemolysin, lipase, coagulase, serine protease (Ssp)} and especially protein A (Spa) . Furthermore, the pattern of proteins secreted by both mutants was strikingly different from that of the wild-type strain . Transcriptional fusions showed that expression of hla, ssp and spa was higher in both mutants than in the wild-type strain, indicating that the arl operon decreases the production of virulence factors by downregulating the transcription of their genes . The arl mutation did not change spa expression in an agrA mutant or in a sarA mutant, suggesting that both the sarA and the agr loci are required for the action of arl on spa . Northern blot analyses indicated that the arl mutation increased the synthesis of both RNA II and RNA III, but decreased sarA transcription . Finally, arl was not autoregulated, but its expression was stimulated by agr and sarA . These results suggest that the Arl system interacts with both agr and sarA regulatory loci to modulate the virulence regulation network. Artif Organs, 2001 Jun, 25(6), 490 - 4 Antibacterial effect of antibiotic solution on cellular viability in canine veins; Park JC et al.; Pretreatment of tissue by using antibiotics is a critical step to prevent microbial contamination before venous transplantation . In this study, the optimal time and temperature of antibiotic solution treatment for maintaining cellular viability with antibacterial effect were investigated . The antibiotic-nutrient solutions were composed of cefoxitin, lincomycin, vancomycin, and polymyxin B in RPMI-1640 medium . After various antibiotic solution treatment times (4, 8, and 12 h) and temperatures (4, 25, and 37 degrees C), the viabilities of cells dissociated from veins (jugular vein, femoral vein, superior vena cava, and inferior vena cava) were determined . Double staining by Griffonia simplicifolia agglutins-fluorescein isothiocyanate (GS1-FITC) and propidium iodide was used . To measure the antibacterial effect of the antibiotic solution, canine veins were artificially infected by 3 kinds of bacteria (Staphylococcus aureus, Escherichia coli, and Klebsiella pneumoniae) and were treated by antibiotic solutions as viability test conditions . After the treatment with the antibiotic solution, the tissue was minced, and the homogenized tissue fraction was cultured on standard method agar . The colony that seemed to be resistant to the antibiotic solution was counted . At 37 and 25 degrees C, the viability of whole cells decreased significantly Asymptotic Significance 2-tailed (Asymp.Sig 2-tailed) < 0.05 after 4 h of antibiotic solution treatment, whereas at 4 degrees C it began to reduce significantly after 8 h of treatment . By antibiotic solution treatment at all 3 temperatures for 4 h, no significant difference in viability of the endothelial cells and whole cells was observed . To maintain the donor vein's cellular viability until transplantation, antibiotic solution treatment for 4 h at 4 degrees C is assumed to be appropriate. Eur J Clin Microbiol Infect Dis, 2001 May, 20(5), 343 - 5 Effect of iron limitation on slime production by Staphylococcus aureus; Baldassarri L et al.; The aim of this study was to examine the effect of growth conditions on slime production by Staphylococcus aureus clinical isolates . The addition of glucose to the medium enhanced slime production in the majority of Staphylococcus aureus isolates cultured from infections associated with orthopaedic prostheses . Iron limitation also stimulated this ability even in the absence of the additional carbohydrate source . Staphylococcus aureus isolates were classified as Group 1 {strains producing slime only in trypticase soy broth supplemented with 1% glucose (TSBG) or in iron-limited trypticase soy broth (TSB/Fe-)}; Group 2 (slime + only in TSB/Fe-); or Group 3 (slime+ only in TSBG) . Seven repeatedly slime-negative strains were stimulated to produce slime by subpassaging in iron-limited medium . Low iron levels, usually found in vivo, could stimulate slime production by Staphylococcus aureus and support chronic infections associated with orthopaedic prostheses. J Neurosurg Spine, 2001 Jul, 95(1), 135 - 8 Hematogenous pyogenic facet joint infection of the subaxial cervical spine . A report of two cases and review of the literature; Muffolerro AJ et al.; Two cases of hematogenous, pyogenic, subaxial cervical facet joint infection are reported, and the literature is reviewed . Infection of the cervical facet joint is a rarely diagnosed condition; only one case has been reported in the literature . Lumbar facet joint infections are also rare but more commonly reported . Approximately one fourth of facet joint infections in the lumbar spine are complicated by epidural abscess formation, which can lead to a neurological deficit . Because of the paucity of reports on cervical facet joint infections, the clinical characteristics of this entity are not well known . Both patients presented with an acute onset of unilateral neck pain that radiated into the ipsilateral shoulder . Frank radicular pain was initially absent . Unilateral upper-extremity motor weakness that was attributed to associated epidural abscess or granulation tissue formation was also demonstrated in both patients . Leukocyte count and erythrocyte sedimentation rate were elevated in both cases . Magnetic resonance imaging was necessary to obtain an accurate diagnosis . Staphylococcus aureus was identified as the offending pathogen in both cases . Decompressive surgery and antibiotic therapy were required to cure the condition . One patient recovered completely and the other sustained a permanent motor deficit . Hematogenous cervical facet joint infection is a rare clinical entity that has many characteristics in common with the more-common lumbar homolog . All three reported cases, however, have been complicated by epidural abscess or granulation tissue formation that has led to a neurological deficit . This finding suggests that a facet joint infection in the cervical spine may have a less benign clinical course than that in the lumbar spine. J Neurosurg Spine, 2001 Jul, 95(1), 100 - 4 Pyogenic abscess of the filum terminale . Case report; Thome C et al.; Intradural spinal abscesses are rare . They are predominantly encountered as intramedullary abscesses of the spinal cord and infrequently as subdural lesions . To their knowledge, the authors report the first case of a chronic pyogenic abscess of the terminal filum in an adult woman with kyphoscoliosis who presented with lumbar radiculopathies . Magnetic resonance imaging revealed a partly cystic intradural L3-4 mass that markedly enhanced after contrast administration . Laboratory signs of infection were absent . Intraoperatively a lobulated lesion observed within the terminal filum was tightly attached to neighboring nerve roots by fibrosis . On opening the cyst wall pus was revealed . Histological examination confirmed the diagnosis of a chronic abscess . Microbiological culture detected Staphylococcus aureus . Antibiotic therapy resulted in an uneventful postoperative course, with complete resolution of symptoms and radiologically demonstrated disappearance of the lesion . The pathogenesis and radiological features of the lesion are discussed . Although extremely rare, a pyogenic abscess should be considered in the differential diagnosis of mass lesions of the cauda equina, especially in patients with preexisting spinal abnormalities . Surgical exposure, including drainage and biopsy sampling to rule out underlying tumor, combined with antibiotic treatment result in a favorable outcome. Rev Inst Med Trop Sao Paulo, 2001 May-Jun, 43(3), 145 - 8 Microbicidal effect of medicinal plant extracts (Psidium guajava Linn . and Carica papaya Linn.) upon bacteria isolated from fish muscle and known to induce diarrhea in children; Vieira RH et al.; Out of the twenty-four samples of shrimp and fish muscle used for this study, twelve were collected near a large marine sewer for waste disposal, 3 km off the coast of Fortaleza (Brazil) and used for the isolation of E . coli . Other twelve were collected at the Mucuripe fresh fish market (Fortaleza, Brazil) and used for the isolation of Staphylococcus aureus . Ethanol, water and acetone-diluted extracts of guava and papaya leaf sprouts were tested on the bacteria in order to verify their microbicidal potential . The E . coli strains used in the trials were rated LT positive . The papaya leaf extracts (Carica papaya Linn) showed no microbicidal activity while the guava sprout extracts (Psidium guajava Linn) displayed halos exceeding 13 mm for both species, an effect considered to be inhibitory by the method employed . Guava sprout extracts by 50% diluted ethanol most effectively inhibited E . coli (EPEC), while those in 50% acetone were less effective . It may be concluded that guava sprout extracts constitute a feasible treatment option for diarrhea caused by E . coli or by S . aureus-produced toxins, due to their quick curative action, easy availability in tropical countries and low cost to the consumer. Antimicrob Agents Chemother, 2001 Aug, 45(8), 2358 - 62 Once-daily oral gatifloxacin versus oral levofloxacin in treatment of uncomplicated skin and soft tissue infections: double-blind, multicenter, randomized study; Tarshis GA et al.; This was a double-blind, multicenter study in which 410 adults (> or =18 years of age) with uncomplicated skin and soft tissue infections (SSTIs) were randomized to receive either 400 mg of gatifloxacin orally once daily or 500 mg of levofloxacin orally once daily for 7 to 10 days . The study protocol called for four assessments-before and during treatment, at the end of treatment, and posttreatment . Efficacy evaluations included clinical response and bacterial eradication rates . Of 407 treated patients, 202 (108 women, 94 men) received gatifloxacin and 205 (111 women, 94 men) received levofloxacin . For clinically evaluable patients, the cure rates were 91% for gatifloxacin and 84% for levofloxacin (95% confidence interval {CI} for the difference, -2.0 to 15.2%) . Clinical cure rates for microbiologically evaluable patients were 93% for gatifloxacin and 88% for levofloxacin (95% CI for the difference, -6.5 to 16.8%) . The bacterial eradication rate was 92% for each group, with gatifloxacin eradicating 93% of the methicillin-susceptible Staphylococcus aureus isolates and levofloxacin eradicating 91% of them . Both drugs were well tolerated . Most of the adverse events were mild to moderate, and nausea was the most common adverse event in each treatment arm . Once-daily oral gatifloxacin (400 mg) is clinically efficacious and well tolerated compared with once-daily levofloxacin (500 mg) for the treatment of patients with uncomplicated SSTIs. Antimicrob Agents Chemother, 2001 Aug, 45(8), 2304 - 8 Efficacy of linezolid in treatment of experimental endocarditis caused by methicillin-resistant Staphylococcus aureus; Dailey CF et al.; The efficacies of orally (p.o.) dosed linezolid and intravenously (i.v.) dosed vancomycin against methicillin-resistant Staphylococcus aureus (MRSA) in rabbits with experimental aortic-valve endocarditis were investigated . After endocarditis was established with a recent clinical MRSA isolate, rabbits were dosed for 5 days with linezolid (p.o., three times a day) at either 25, 50, or 75 mg/kg of body weight or vancomycin (i.v., twice a day) at 25 mg/kg . The 25-mg/kg linezolid group had a high mortality rate and bacterial counts in the valve vegetations that were not different from those of the controls . Linezolid dosed p.o . at 50 and 75 mg/kg and i.v . vancomycin produced statistically significant reductions in bacterial counts compared to those of the untreated controls . The reduced bacterial counts and culture-negative valve rates for the animals treated with linezolid at 75 mg/kg were similar to those for the vancomycin-treated animals . Concentrations of linezolid in plasma were determined at several points in the dosing regimen . These results suggest that the efficacy of linezolid in this infection model is related to trough levels in plasma that remain above the MIC for this microorganism . At the ineffective dose of linezolid (25 mg/kg) the concentration at sacrifice was 0.045 times the MIC, whereas the concentrations of linezolid in plasma in the 50- and 75-mg/kg groups were 2 and 5 times the MIC at sacrifice, respectively . The results from this experimental model suggest that the oxazolidinone linezolid may be effective for the treatment of serious staphylococcal infections when resistance to other antimicrobials is present. Burns, 2001 Aug, 27(5), 504 - 8 Minor {correction of Mi1nor} burns and pneumatocoeles: a case report; George A et al.; Minor burns in children need to be cautiously managed as they may manifest with life threatening complications especially in the presence of staphylococcal infection . A one and a half year old child with minor burns (12% TBSA), who developed large pneumatocoeles and peumomediastinum following Staphylococcus aureus pneumonia causing severe respiratory distress and needing ventilatory support is presented . Most of the pneumatocoeles were spontaneously absorbed over a period of 10 days while surgical interference was being contemplated . A conservative approach to pneumatocoeles as in non-burn patients may help prevent unnecessary surgery . An extensive English literature search (since 1966) did not reveal any report of pneumatocoeles in association with burns and therefore we believe this to be the first report of its kind. J Chemother, 2001 Jun, 13(3), 281 - 7 Cost-effectiveness of cefepime + netilmicin or ceftazidime + amikacin or meropenem monotherapy in febrile neutropenic children with malignancy in Turkey; Agaoglu L et al.; Infection remains the major cause of morbidity and mortality in immunocompromised children with malignancy . In addition, the economic impact of antibiotic treatment should always be evaluated, especially in developing countries . In our center between January 1998 and January 1999, 73 children with hematological malignancies {acute lymphoblastic leukemia (ALL), acute myeloid leukemia (AML)}; 9 children with solid tumors (rhabdomyosarcoma, neuroblastoma) had 87 febrile neutropenic episodes (related to chemotherapy) . These children were randomized prospectively into three treatment groups . The first group (n: 28) received cefepime plus netilmicin, while the second group (n: 29) was treated with ceftazidime plus amikacin and the third (n: 30) with meropenem as monotherapy . The aim of the study was to compare the success rates and cost of fourth generation cephalosporin plus aminoglycoside and monotherapy of meropenem with ceftazidime plus amikacin, which is the standard therapy for febrile neutropenia . Microbiologically documented infections were 29.9%, clinically documented infections were 9.2% and 60.9% of the febrile neutropenic episodes were considered to be FUO . Gram-positive microorganisms were the most commonly isolated agents from blood cultures {MRSA (Methicillin Resistant Staphylococcus aureus) in 6 patients and MSSA (Methicillin Sensitive Staphylococcus aureus) in 4 patients} . The success rates were 78.5%, 79.3% and 73.3 % for the 1st, 2nd and 3rd groups respectively . In 4 patients (4.5%) fever responded only to amphotericin-B therapy . There was no statistically significant difference between the three treatment regimens with respect to efficacy, safety and tolerance (chi2 test, p>0.05), but while the third and fourth generation cephalosporins + aminoglycosides were comparable for cost, the monotherapy regimen was the most expensive . The main determining factors for the choice of treatment of febrile neutropenic children, especially in a developing country, are cost, presence of indwelling catheter and the bacterial flora of the unit, as well as efficacy. Vox Sang, 2001 Apr, 80(3), 170 - 8 Bacteria-induced release of white cell--and platelet-derived vascular endothelial growth factor in vitro; Nielsen HJ et al.; BACKGROUND AND OBJECTIVES: Poor prognosis after resection of primary colorectal cancer may be related to the combination of perioperative blood transfusion and subsequent development of infectious complications . White blood cell--and platelet-derived cancer growth substances, including vascular endothelial growth factor (VEGF), may be involved in this process . Therefore, we studied the in vitro release of VEGF from white blood cells and platelets stimulated by bacterial antigens and supernatants from stored red cell components . MATERIALS AND METHODS: Eight units of whole blood (WB) and eight units of buffy-coat-depleted red cell (SAGM) blood were donated by healthy blood donors . Subsequently, half of every unit was leucocyte depleted by filtration, and all 32 half-units were stored under standard conditions for 35 days . Just after storage, and on days 7, 21 and 35 during storage, aliquots of the supernatants were removed from the units and frozen at -80 degrees C . WB from other healthy donors was stimulated for 2 h with sodium chloride (controls), with Escherichia coli lipopolysaccharide (LPS) alone, or with LPS plus supernatants from the non-filtered or prestorage leucofiltered WB units (diluted 1:10), or from non-filtered or prestorage leucofiltered SAGM blood units (diluted 1:20) stored for 0, 7, 21, or 35 days, respectively . Similar assays were performed using Staphylococcus aureus-derived protein A as a stimulatory antigen . The concentration of VEGF was determined in supernatants from stored blood and in assay supernatants by using enzyme-linked immunosorbent assay (ELISA) . RESULTS: The concentration of VEGF increased significantly (P < 0.0001) in a storage time-dependent manner in non-filtered WB and SAGM blood, while the increase was abrogated by prestorage leucofiltration . The supernatant concentration of VEGF was significantly increased in LPS-stimulated (P = 0.002) and in protein A-stimulated (P < 0.0001) assays compared with controls . Addition of supernatants from stored, non-filtered WB or SAGM significantly increased the assay supernatant VEGF concentration storage-time dependently (P = 0.006) in LPS assays . In protein A assays, only supernatants from non-filtered WB significantly increased the assay supernatant VEGF concentration storage-time dependently (P = 0.022) . This additional effect by supernatants from stored blood components was not observed with prestorage leucofiltered blood . CONCLUSIONS: Extracellular VEGF may accumulate in non-filtered red cell components, but this can be prevented by prestorage leucocyte depletion using filtration . In addition, bacterial antigens appear to induce release of VEGF from white blood cells and platelets . Addition of supernatants from stored, non-filtered WB or SAGM blood may increase the VEGF levels in a storage time-dependent manner, while prestorage leucofiltration may prevent further increase by supernatants. J Radiol, 2001 Jun, 82(6 Pt 1), 665 - 9 {Cross-sectional imaging of post endocarditis paravalvular myocardial abscesses of native mitral valves: 4 cases}; Reynier C et al.; Four cases of submitral myocardial abscess imaged by CT or MRI following endocarditis are described . All cases occurred in fragile patients (diabetes mellitus, dialysis, severe cardiovascular diseases) . An iatrogenic source was noted in one patient . Staphylococcus aureus was responsible in 2 patients . If subvalvular aortic abscesses are usually described, submitral myocardial abscesses are infrequent . In addition to transesophageal echocardiography, a technique superior to transthoracic echocardiography, CT and MRI may incidentally suggest the correct diagnosis . Both techniques provide useful morphological evaluation, information that can be used to optimize the timing for surgical repair. Diagn Microbiol Infect Dis, 2001 May-Jun, 40(1-2), 67 - 70 Proposed quality control guidelines for National Committee for Clinical Laboratory Standards Susceptibility Tests using the veterinary antimicrobial agent tiamulin; Pfaller MA et al.; Quality control guidelines for standardized antimicrobial susceptibility test methods are critical for the continuing accuracy of these clinical tests . In this report, quality control limits were proposed for the veterinary antimicrobial agent tiamulin with minimum inhibitory concentration (MIC) ranges of three or four log(2) dilution steps in two different medium formulations . Disk diffusion zone diameter ranges were proposed for tiamulin tested against Actinobacillus pleuropneumoniae ATCC 27090 (12-18 mm) and Staphylococcus aureus ATCC 25923 (25-32 mm) . The data from eight participating laboratories produced 100% of results within proposed MIC limits (8-32 microg/mL), and 95.8-97.0% of zones were found within suggested zone diameter QC guidelines . These proposed QC ranges should be validated by in-use results from veterinary clinical laboratories. Diagn Microbiol Infect Dis, 2001 May-Jun, 40(1-2), 5 - 10 Comparison of the Velogene Rapid MRSA Identification Assay, Denka MRSA-Screen Assay, and BBL Crystal MRSA ID System for rapid identification of methicillin-resistant Staphylococcus aureus; Arbique J et al.; Early detection of methicillin-resistant S.aureus (MRSA) is critical for both the management of infected patients, and the timely institution of appropriate infection control measures . Although detection of the mecA gene by PCR remains the gold standard, this technology is inaccessible for many laboratories . Therefore, we sought to evaluate several new rapid identification systems and compare them to PCR . A total of 71 methicillin-susceptible S . aureus (MSSA), 25 borderline oxacillin-resistant S . aureus (BORSA), and 213 MRSA were selected for study . S.aureus was identified using standard methods . Initial screening was performed on a Mueller-Hinton agar plate with 6 mg/L of oxacillin . MRSA strains were identified using PCR with primers specific for the mecA gene . PCR was used as the reference method . All isolates were tested using the BBL Crystal MRSA ID System (Becton Dickinson Microbiology Systems, Maryland, USA), the MRSA-Screen Assay (Denka Seiken Co., Ltd., Tokyo, Japan), and the Velogene Rapid MRSA Identification Assay (ID Biomedical Corp, Vancouver, BC) . With minor modifications, all assays were performed according to manufacturers' instructions . Overall, the 3 commercial assays performed well . The sensitivity and specificity of the BBL, Denka, and Velogene systems were 99%/100%, 99%/100%, and 96%/100% respectively . The advantages of the phenotypic tests-BBL Crystal Kit and Denka MRSA-Screen Assay include lower cost per test, shelf-life, ease of use, and rapid turn-around times . Advantages of the Velogene Rapid MRSA include ability to perform genotypic high-volume testing without the equipment requirements and technical complexity involved with PCR . Turn-around times ranged from 15 min for the Denka MRSA-Screen Assay, 2 h for the Velogene Rapid MRSA, and 4 h for the BBL Crystal . The BBL Crystal, Denka MRSA-Screen, and Velogene Rapid MRSA identification systems are rapid, easy to perform, and provide accurate identification of MRSA . These rapid kits offer an acceptable alternative for smaller, non-reference, laboratories and reduce the dependency on PCR in larger laboratories for routine confirmation. Diagn Microbiol Infect Dis, 2001 May-Jun, 40(1-2), 1 - 4 Emergence of methicillin-resistant Staphylococcus aureus as a community pathogen; Bukharie HA et al.; Methicillin-Resistant Staphylococcus aureus (MRSA) infection is an established nosocomial pathogen, with hospital-based outbreaks occurring worldwide . An increase in MRSA infections without risk factors has been recently documented in several reports . A prospective study was conducted over a 36-month period to determine the prevalence and risk factors for community-acquired MRSA infection at King Fahad Hospital of the University Al-Khobar, Saudi Arabia . Patients hospitalized within the previous 12 months or transfers from hospitals or nursing homes were excluded . The number of patients with community-acquired MRSA disease increased from a single patient in 1998 to fifteen patients in the year 2000 and the percentage of community-acquired MRSA/total number of MRSA increased from 5% to 33% . Fifteen (75%) of 20 patients with community-acquired MRSA infection had no discernible characteristics of MRSA infections . Skin and soft tissue infections were the predominant presentation . Most MRSA isolates (95%) were susceptible to multiple antibiotics . Our data suggest that MRSA is an emerging community pathogen . Hospital infection control strategies will have to be redefined and community approaches developed to reduce transmission. J Am Soc Echocardiogr, 2001 Jul, 14(7), 750 - 3 Value of repeated multiplane transesophageal echocardiography in a patient with mitral valve ring abscess and left ventricular pseudoaneurysm; Wisbar A et al.; Mitral valve ring abscess and ventricular pseudoaneurysm are rare complications of infective endocarditis . We describe the case of a 58-year-old man who was admitted to our hospital with sepsis caused by Staphylococcus aureus and in whom tricuspid and mitral valve endocarditis developed within 2 weeks . Despite widespread antibiotic therapy, the endocarditis proceeded to form a mitral valve ring abscess and a left ventricular pseudoaneurysm . The diagnosis was set by repeated multiplane transesophageal echocardiography and confirmed by heart surgery. Proc Natl Acad Sci U S A, 2001 Jul 17, 98(15), 8821 - 6 Epub 2001 Jul 10. Evolutionary genomics of Staphylococcus aureus: insights into the origin of methicillin-resistant strains and the toxic shock syndrome epidemic; Fitzgerald JR et al.; An emerging theme in medical microbiology is that extensive variation exists in gene content among strains of many pathogenic bacterial species . However, this topic has not been investigated on a genome scale with strains recovered from patients with well-defined clinical conditions . Staphylococcus aureus is a major human pathogen and also causes economically important infections in cows and sheep . A DNA microarray representing >90% of the S . aureus genome was used to characterize genomic diversity, evolutionary relationships, and virulence gene distribution among 36 strains of divergent clonal lineages, including methicillin-resistant strains and organisms causing toxic shock syndrome . Genetic variation in S . aureus is very extensive, with approximately 22% of the genome comprised of dispensable genetic material . Eighteen large regions of difference were identified, and 10 of these regions have genes that encode putative virulence factors or proteins mediating antibiotic resistance . We find that lateral gene transfer has played a fundamental role in the evolution of S . aureus . The mec gene has been horizontally transferred into distinct S . aureus chromosomal backgrounds at least five times, demonstrating that methicillin-resistant strains have evolved multiple independent times, rather than from a single ancestral strain . This finding resolves a long-standing controversy in S . aureus research . The epidemic of toxic shock syndrome that occurred in the 1970s was caused by a change in the host environment, rather than rapid geographic dissemination of a new hypervirulent strain . DNA microarray analysis of large samples of clinically characterized strains provides broad insights into evolution, pathogenesis, and disease emergence. Infect Immun, 2001 Aug, 69(8), 5198 - 202 Identification and analysis of Staphylococcus aureus components expressed by a model system of growth in serum; Wiltshire MD et al.; A model system mimicking Staphylococcus aureus bacteremia was developed by growth in serum under microaerobic conditions . Eight genes induced by growth in serum were identified, including an antimicrobial peptide biosynthesis locus, amino acid biosynthetic loci, and genes encoding putative surface proteins . Nine independent insertions were found in the major lysine biosynthesis operon, which encodes eight genes, is repressed by lysine in vitro, and is expressed in vivo. Infect Immun, 2001 Aug, 69(8), 5193 - 7 Toxin levels in serum correlate with the development of staphylococcal scalded skin syndrome in a murine model; Plano LR et al.; Staphylococcal scalded skin syndrome (SSSS) is an exfoliative dermatitis that results from infection with exfoliative toxin-producing Staphylococcus aureus . SSSS is seen primarily in infants and children . Here we ask if there is a specific maturation process that protects healthy adults from this syndrome . For these studies, an active recombinant exfoliative toxin A (rETA) was used in a neonatal mouse model . A time course generated on the susceptibility to the toxin as a function of mouse age indicated that BALB/c mice developed the characteristic symptoms of SSSS until day 7 of life . Between day 7 and day 8 of life there was a dramatic decrease in susceptibility, such that mice at day 9 of life were resistant to the effects of the toxin . This time course corresponds approximately to the time needed for maturation of the adaptive immune response, and SSSS in adults is often identified with immunocompromised states . Therefore, mice deficient in this response were examined . Adult mice thymectomized at birth and adult SCID mice did not develop the symptoms of SSSS after injection with the toxin, indicating that the adaptive immune response is not responsible for the lack of susceptibility observed in the older mice . SSSS in adults is also associated with renal disorders, suggesting that levels of toxin in serum are important in the development of the disease . rETA was not cleared as efficiently from the serum of 1-day-old mice compared to clearance from 10-day-old mice . Ten-day-old mice were given repeated injections of toxin so that the maximal level of toxin was maintained for a sustained period of time, and exfoliation occurred in these mice . Thus, whereas the adaptive immune response is not needed for protection of adult mice from SSSS, efficient clearance of the toxin from the bloodstream is a critical factor. Infect Immun, 2001 Aug, 69(8), 4916 - 22 Diversity in antistaphylococcal mechanisms among membrane-targeting antimicrobial peptides; Koo SP et al.; Many antimicrobial peptides permeabilize the bacterial cytoplasmic membrane . However, it is unclear how membrane permeabilization and antimicrobial activity are related for distinct peptides . This study investigated the relationship between Staphylococcus aureus membrane permeabilization and cell death due to the following antistaphylococcal peptides: thrombin-induced platelet microbicidal protein 1 (tPMP-1), gramicidin D, and protamine . Isogenic S . aureus strains ISP479C and ISP479R (tPMP-1 susceptible and resistant, respectively), were loaded with the fluorochrome calcein and exposed to a range of concentrations of each peptide . Flow cytometry was then used to monitor membrane permeabilization by quantifying the release of preloaded calcein . Killing was determined by quantitative culture at time points simultaneous to measurement of membrane permeabilization . Membrane permeabilization and killing caused by tPMP-1 occurred in a time- and concentration-dependent manner, reflecting the intrinsic tPMP-1 susceptibilities of ISP479C and ISP479R . In comparison, gramicidin D killed both S . aureus strains to equivalent extents in a concentration-dependent manner between 0.5 to 50 microg/ml, but cell permeabilization only occurred at the higher peptide concentrations (25 and 50 microg/ml) . Protamine permeabilized, but did not kill, either strain at concentrations up to 10 mg/ml . Regression analyses revealed different relationships between membrane permeabilization and staphylocidal activity for the distinct antimicrobial peptides . Taken together, these findings demonstrate that permeabilization, per se, does not invariably result in staphylococcal death due to distinct antimicrobial peptides . Thus, although each of these peptides interacts with the S . aureus cytoplasmic membrane, diversity exists in their mechanisms of action with respect to the relationship between membrane permeabilization and staphylocidal activity. Infect Immun, 2001 Aug, 69(8), 4749 - 58 SarT, a repressor of alpha-hemolysin in Staphylococcus aureus; Schmidt KA et al.; In searching the Staphylococcus aureus genome, we found several homologs to SarA . One of these genes, sarT, codes for a basic protein with 118 residues and a predicted molecular size of 16,096 Da . Northern blot analysis revealed that the expression of sarT was repressed by sarA and agr . An insertion sarT mutant generated in S . aureus RN6390 and 8325-4 backgrounds revealed minimal effect on the expression of sarR and sarA . The RNAIII level was notably increased in the sarT mutant, particularly in postexponential-phase cells, while the augmentative effect on RNAII was less . SarT repressed the expression of alpha-hemolysin, as determined by Northern blotting, Western blotting, and a rabbit erythrocyte hemolytic assay . This repression was relieved upon complementation . Similar to agr and sarA mutants, which predictably displayed a reduction in hla expression, the agr sarT mutant exhibited a lower level of hla transcription than the sarT mutant . In contrast, hla transcription was enhanced in the sarA sarT mutant compared with the single sarA mutant . Collectively, these results indicated that the sarA locus, contrary to the regulatory action of agr, induced alpha-hemolysin production by repressing sarT, a repressor of hla transcription. Infect Immun, 2001 Aug, 69(8), 4742 - 8 Decreased amounts of cell wall-associated protein A and fibronectin-binding proteins in Staphylococcus aureus sarA mutants due to up-regulation of extracellular proteases; Karlsson A et al.; Data have been presented indicating that Staphylococcus aureus cell surface protein can be degraded by extracellular proteases produced by the same bacterium . We have found that in sarA mutant cells, which produce high amounts of four major extracellular proteases (staphylococcal serine protease {V8 protease} {SspA}, cysteine protease {SspB}, aureolysin {metalloprotease} {Aur}, and staphopain {Scp}), the levels of cell-bound fibronectin-binding proteins (FnBPs) and protein A were very low compared to those of wild-type cells, in spite of unaltered or increased transcription of the corresponding genes . Cultivation of sarA mutant cells in the presence of the global protease inhibitor alpha(2)-macroglobulin resulted in a 16-fold increase in cell-bound FnBPs, indicating that extracellular proteases were responsible for the decreased amounts of FnBPs in sarA mutant cells . The protease inhibitor E64 had no effect on the level of FnBPs, indicating that cysteine proteases were not involved . Inactivation of either ssp or aur in the prototype S . aureus strain 8325-4 resulted in a threefold increase in the amount of cell-bound FnBPs . Inactivation of the same protease genes in a sarA mutant of 8325-4 resulted in a 10- to 20-fold increase in cell-bound protein A . As the serine protease requires aureolysin to be activated, it can thus be concluded that the serine protease is the most important protease in the release of cell-bound FnBPs and protein A. Res Microbiol, 2001 Jun, 152(5), 503 - 14 Class II broad-spectrum mercury resistance transposons in Gram-positive bacteria from natural environments; Bogdanova E et al.; We have studied the mechanisms of the horizontal dissemination of a broad-spectrum mercury resistance determinant among Bacillus and related species . This mer determinant was first described in Bacillus cereus RC607 from Boston Harbor, USA, and was then found in various Bacillus and related species in Japan, Russia and England . We have shown that the mer determinant can either be located at the chromosome, or on a plasmid in the Bacillus species, and is carried by class II mercury resistance transposons: Tn5084 from B . cereus RC607 and B . cereus VKM684 (ATCC10702) and Tn5085 from Exiguobacterium sp . TC38-2b . Tn5085 is identical in nucleotide sequence to TnMERI1, the only other known mer transposon from Bacillus species, but it does not contain an intron like TnMERI1 . Tn5085 is functionally active in Escherichia coli . Tn5083, which we have isolated from B . megaterium MK64-1, contains an RC607-like mer determinant, that has lost some mercury resistance genes and possesses a merA gene which is a novel sequence variant that has not been previously described . Tn5083 and Tn5084 are recombinants, and are comprised of fragments from several transposons including Tn5085, and a relative of a putative transposon from B . firmus (which contains similar genes to the cadmium resistance operon of Staphylococcus aureus), as well as others . The sequence data showed evidence for recombination both between transposition genes and between mer determinants. J Med Microbiol, 2001 Jul, 50(7), 646 - 9 In-vitro antimicrobial activity of four diallyl sulphides occurring naturally in garlic and Chinese leek oils; Tsao SM et al.; The in-vitro antimicrobial activity of garlic oil, Chinese leek oil and four diallyl sulphides occurring naturally in these oils against Staphylococcus aureus, methicillin-resistant S . aureus (MRSA), three Candida spp . and three Aspergillus spp . (total of 276 clinical isolates) was studied . The magnitude of activity of the four diallyl sulphides followed the order diallyl tetrasulphide > diallyl trisulphide > diallyl disulphide > diallyl monosulphide . These results suggest that disulphide bonds are an important factor in determining the antimicrobial capabilities of these sulphides . The concentration of four diallyl sulphides in garlic and Chinese leek oils was in the range 41.7-52.7% of total sulphides . Garlic oil, with a higher concentration of four diallyl sulphides, showed greater antimicrobial activity than Chinese leek oil . Diallyl disulphide, diallyl trisulphide, diallyl tetrasulphide and the oils rich in these sulphides may have a role in the prevention or treatment of infections. J Med Microbiol, 2001 Jul, 50(7), 588 - 93 Genotyping of European isolates of methicillin-resistant Staphylococcus aureus by fluorescent amplified-fragment length polymorphism analysis (FAFLP) and pulsed-field gel electrophoresis (PFGE) typing; Grady R et al.; A representative panel of 50 European MRSA isolates was subjected to genotype analysis by fluorescent amplified-fragment length polymorphism (FAFLP) and by macrorestriction pulsed-field gel electrophoresis (PFGE) . Each isolate had a unique profile with FAFLP . To model genetic relationships within the continuing MRSA epidemic, cluster analysis of FAFLP data was made, revealing nine clone complexes of MRSA . Most of these were also found by PFGE . A number of isolates had FAFLP profiles significantly different from others, and might represent emerging epidemic strains . FAFLP analysis proved particularly suitable for surveillance of the MRSA epidemic at national and international levels. J Bacteriol, 2001 Aug, 183(15), 4609 - 13 Regulation of Staphylococcus aureus type 5 and type 8 capsular polysaccharides by CO(2); Herbert S et al.; Staphylococcus aureus expression of capsular polysaccharide type 5 (CP5) has been shown to be downregulated by CO(2) . Here we show that CO(2) reduces CP5 expression at the transcriptional level and that CO(2) regulates CP8 expression depending on the genetic background of the strains . Growth in the presence of air supplemented with 5% CO(2) caused a significant decrease in CP8 expression in four S . aureus strains, a marginal effect in four strains, and higher CP8 expression in strain Becker . Absolute CP8 expression in the nine S . aureus strains differed largely from strain to strain . Four groups of strains were established due to sequence variations in the promoter region of cap5 and cap8 . To test whether these sequence variations are responsible for the different responses to CO(2), promoter regions from selected strains were fused to the reporter gene xylE in pLC4, and the plasmids were electrotransformed into strains Becker and Newman . XylE activity was negatively regulated by CO(2) in all derivatives of strain Newman and was always positively regulated by CO(2) in all derivatives of strain Becker . Differences in promoter sequences did not influence the pattern of CP8 expression . Therefore, the genetic background of the strains rather than differences in the promoter sequence determines the CO(2) response . trans-acting regulatory molecules may be differentially expressed in strain Becker versus strain Newman . The strain dependency of the CP8 expression established in vitro was also seen in lung tissue sections of patients with cystic fibrosis infected with CP8-positive S . aureus strains. Mol Microbiol, 2001 Jun, 40(6), 1439 - 47 Impact of the regulatory loci agr, sarA and sae of Staphylococcus aureus on the induction of alpha-toxin during device-related infection resolved by direct quantitative transcript analysis; Goerke C et al.; The cytotoxic alpha-toxin (encoded by hla) of Staphylococcus aureus is regulated by three loci, agr, sarA and sae, in vitro . Here, we assess the regulation of hla in a guinea pig model of device-related infection by quantifying RNAIII (the effector molecule of agr) and hla directly in exudates accumulating in infected devices without subculturing of the bacteria . LightCycler reverse transcription-polymerase chain reaction (RT-PCR) was used to quantify the transcripts . Strains RN6390 and Newman expressed considerably smaller amounts of RNAIII in the guinea pig than during in vitro growth . The residual RNAIII expression decreased during the course of infection and was negatively correlated with bacterial densities . As with RNAIII, the highest hla expression was detected in both strains early in infection . Even in strain Newman, a weak hla producer in vitro, a pronounced expression of hla was observed during infection . Likewise, four S . aureus isolates from cystic fibrosis (CF) patients expressed Q1hla despite an inactive agr during device-related infection as in the CF lung . Mutation of agr and sarA in strain Newman and RN6390 had no consequence for hla expression in vivo . In contrast, the mutation in sae resulted in severe downregulation of hla in vitro as well as in vivo . In conclusion, S . aureus seems to be provided with regulatory circuits different from those characterized in vitro to ensure alpha-toxin synthesis during infections. Clin Microbiol Infect, 2001 Jun, 7(6), 301 - 7 Recent developments in staphylococcal scalded skin syndrome; Ladhani S; Staphylococcal scalded skin syndrome describes a spectrum of superficial blistering skin disorders caused by the exfoliative toxins of Staphylococcus aureus . In its severe form, the exfoliation can spread to cover the entire body surface area . Two S . aureus exfoliative toxin serotypes affecting humans have been identified, but their purpose and mechanism of action have remained elusive . Based on their interaction with human and mouse epidermis, their three-dimensional structure and site-directed mutagenesis studies, it is speculated that they act as atypical serine proteases, and desmoglein-1 has now been identified as the specific epidermal substrate . Recent studies also suggest that the toxins may have a unique superantigenic activity . Clinically, new rapid diagnostic tests have been developed, including one that is able to detect the toxins directly from serum . With early diagnosis and appropriate management, mortality in children remains low and long-term complications are rare because the lesions are superficial and heal rapidly without scarring . In adults, however, the condition carries a mortality of almost 60% despite aggressive treatment, usually because of serious underlying illness . The recent developments in our understanding of the exfoliative toxins should lead to new and improved diagnostic and therapeutic strategies, including the use of specific antixoxins to prevent exfoliation. Scand J Infect Dis, 2001, 33(5), 333 - 8 Antibiotic susceptibility patterns of community- and hospital-acquired Staphylococcus aureus and Escherichia coli in Estonia; Karki T et al.; This study compares the susceptibility patterns of Staphylococcus aureus and Escherichia coli isolated from patients with hospital-acquired and outpatient infections . A total of 902 isolates of S . aureus and 1,114 of E . coli were collected in five different Estonian medical centers between January 1997 and November 1997 . Strains were grouped into two different categories, depending on whether they had been obtained from inpatients or outpatients . Compared to S . aureus strains isolated from inpatients, the strains from outpatients were significantly more resistant to erythromycin (25.3% vs . 17.9%), tetracycline (33.5% vs . 22.4%) and trimethoprim-sulfamethoxazole (13.9% vs . 7.9%) . The overall prevalence of oxacillin-resistant S . aureus was 10.4%, with no significant differences noted between isolates recovered from inpatients and outpatients . In the case of E . coli, significantly more isolates from inpatients (42.8%) than from outpatients (34.4%) were ampicillin-resistant . Inpatient isolates of E . coli were also more resistant to cefotaxime (9.3%) and nitrofurantoin (11.2%) than outpatient strains (0% and 3.1%, respectively) . Analysis showed remarkable co-resistance among both inpatient and outpatient strains of S . aureus and E . coli . Multiple resistant S . aureus and E . coli strains represented 15.1% and 17.3%, respectively of the organisms examined in this study . With respect to E . coli, significantly more multiresistant isolates were found in inpatient than outpatient isolates (20.4% vs . 8.9%) . Our results indicate that the distinction between community-acquired and hospital infections due to S . aureus and E . coli may not be valid in Estonia. Eur J Nucl Med, 2001 Jun, 28(6), 730 - 5 Effects of insulin and glucose loading on FDG uptake in experimental malignant tumours and inflammatory lesions; Zhao S et al.; Fluorine-18 2-deoxy-2-fluoro-D-glucose (FDG) accumulation in tumours has been well investigated, but much less is known regarding FDG accumulation in inflammatory lesions . In this study, we determined the effects of hypo- and hyperglycaemia on FDG uptake in inflammatory lesions of infectious and non-infectious origin and compared them with those in malignant tumours in rats, to provide a biological basis for differentiating malignant lesions from benign lesions by means of FDG-PET . Rats were inoculated with a suspension of allogenic hepatoma cells (KDH-8) or Staphylococcus aureus, or with turpentine oil into the left calf muscle . Two weeks after KDH-8 inoculation and 1 week after S . aureus and turpentine oil inoculations, the rats were divided into three subgroups: insulin-loaded (2 U/kg body weight, i.p.), glucose-loaded (1.2 g/kg body weight, p.o.) and control groups . Radioactivity in tissues was determined 1 h after i.v . injection of FDG . Intraperitoneal injection of insulin and oral administration of glucose induced hypoglycaemia and hyperglycaemia, respectively . In the control animals, tumours showed a level of FDG uptake which was 2.2 and 3.0 times higher than the levels in the inflammatory lesions induced by S . aureus and turpentine oil, respectively (P<0.0001) . There was no significant difference in the level of FDG uptake between the two inflammatory lesions of infectious and non-infectious origin . Insulin loading significantly decreased the level of FDG uptake in tumours and in both types of inflammatory lesion to approximately one-half of the control values (P=0.001 in the tumour group and P<0.0001 in the two inflammatory lesion groups) . In the glucose-loaded group, the level of FDG uptake in both types of inflammatory lesion decreased significantly to 50%-61% of the control value (P=0.0002 in the S . aureus group and P<0.0001 in the turpetine group), while the tumour uptake did not decrease significantly (86% of the control value) (P=NS) . It is concluded that FDG uptake in both types of inflammatory lesion was significantly impaired in rats with hyperglycaemia induced by glucose loading, while tumour uptake of FDG was not significantly affected . These results indicate that glucose loading has greater effects on FDG uptake in inflammatory lesions than in tumours, providing a biological basis for differentiation of malignant lesions from benign lesions by FDG-PET in a clinical setting. J Hosp Infect, 2001 Jul, 48(3), 207 - 13 Asymptomatic carriage of Klebsiella pneumoniae producing extended-spectrum beta-lactamase by patients in a neurological early rehabilitation unit: management of an outbreak; Hollander R et al.; During 11 months 58 extended-spectrum beta-lactamase-producing Klebsiella pneumoniae (ESBL-Kp) isolates were grown from 10 patients on a neurological early rehabilitation unit . The patients had no signs of infection but were colonized in the nose and trachea, and unusually only one had colonization in the gut . A single clone of ESBL-Kp was identified by pulse field gel electrophoresis . Strong hygienic precautions similar to those for Methicillin-resistant Staphylococcus aureus patients prevented spread of the bacteria to other wards . However, rehabilitation for patients with severe neurological failures made it very difficult to follow hygienic requirements . Disinfection of mucous membranes was difficult . Eventually the application of a nasal spray containing povidone-iodine proved to be successful . Int J Med Microbiol, 2001 May, 291(2), 159 - 70 Regulation of virulence determinants in Staphylococcus aureus; Arvidson S et al.; The pathogenicity of Staphylococcus aureus depends on the combined action of more than 40 different extracellular toxins, enzymes and cell surface proteins . A global regulator agr controls the production of many of these virulence factors by a regulating RNA molecule, RNAIII . Most of the virulence genes regulated by RNAIII are also regulated by SarA and a family of homologous proteins . The Sar proteins appear to repress transcription of individual virulence genes or sets of genes . As some Sar proteins also repress one or more sar homologous genes an increased production of a single Sar protein can result in decreased expression of some virulence genes, and an increased expression of others . Results are presented suggesting that RNAIII might function as an antirepressor, binding one or more of the Sar proteins. Allergol Immunopathol (Madr), 2001 May-Jun, 29(3), 147 - 51 {The role of infection in asthma}; Fernandez-Benitez M; Since the first decades of the twentieth century, some authors have believed bacterial respiratory infection to be an important triggering factor in bronchial asthma, drawing attention to an asthmatic response to infection . In this context, already in 1995, we presented a study on nasal secretion cultures and the relationship between IgE and sensitization to allergens . There was a statistically significant association between patients with sensitization to Dermatophagoides, elevated IgE levels and Staphylococcus Aureus positive cultures . Following the studies by Norn, we performed a study in 40 children, aged 2-14 years, and observed that these children with sensitization to mites and positive culture released higher histamine levels than did children with negative cultures and controls . The differences were statistically significant . In agreement with other authors, we also found that the presence of both S . aureus and D . pteronyssinus favored antigen specific histamine release . In the last few years, when the increase in the prevalence of bronchial asthma began to be studied, the role of infection, among other factors, in favoring this increase began to be examined . Using the methodology of the ISAAC project, we distributed a parallel questionnaire containing questions on triggering and contributing factors among which was respiratory infection . We found that there was an association between having three of more episodes of bronchitis in the previous year, accompanied by fever and with a duration of more than 7 days and having asthma at some time (OR: 29.09) . This association was even higher in patients with wheezing in the previous 12 months (OR: 43.26) and was also associated with the need to present to the emergency department (OR: 30.65) . From these results we conclude that respiratory infection is an aggravating factor in asthma, as we already know . For several years, several authors have studied how non-nosocomial respiratory infections can directly modulate Th1/Th2 response . In order to obtain our own results, we studied serum interleukin 4 (IL4) and interferon-gamma (IFN-gamma) in 42 children aged 3-17 years . The most frequent IL-4 values expressed in ng/ml were between 0.25-0.40, with little variation in the sample, which did not permit correlation among variables . Concerning IFN-gamma, we found values between < 5 and 605 pg/ml . In children undergoing antigen-specific immunotherapy, we observed mean IFN-gamma values of 115.86 pg/ml, while children not undergoing immunotherapy and those who had been administered this treatment for less than 1 year, had a mean of 66.06 pg/ml . These differences were statistically significant (p = 0.035), thus revealing a Th1 response to immunotherapy . These differences were not statistically significant when children who had been administered immunotherapy for less than 1 year were included . When we studied children with bacterial immunotherapy and grouped them in the same way, we found that the mean IFN-gamma of the children undergoing immunotherapy for more than 1 year was 56.4 pg/ml compared with 101.75 pg/ml in those without immunotherapy . This difference was statistically significant (p = 0.034) . We are able to conclude that bacterial immunotherapy modifies Th1 response, inhibiting it in children with higher susceptibility to infection . In view of these preliminary results, it would be interesting to continue to study interleukins in order to determine the modification of these substances by immunotherapy in a prospective study and with a sample selected in relation to immunotherapy and not other parameters, since those we have studied have shown no relationship. J Chemother, 2001 Apr, 13 Suppl 1, 45 - 9 Infection control practice: global preparedness for future challenges; Soule B et al.; The modern infection control profession emerged in the 1960s in England and the US in response to a pandemic of infections in hospitalized patients from a virulent strain of Staphylococcus aureus . The need for better patient care practices to prevent infections in this setting was evident, and the nursing, medical and microbiology professions responded . Both governmental and non-governmental agencies and professional organizations supported their efforts . During the past 3 decades infection control programs and professionals have multiplied and flourished throughout the world . At first, each country worked primarily within its own borders . In recent years collaboration among countries has increased dramatically, especially as related to education and training, research, and publishing . This article describes two examples of these partnerships . In the US, the Society for Healthcare Epidemiology of America (SHEA) and the Association for Professionals in Infection Control and Epidemiology, Inc (APIC) have joined with the King Fahad National Guard Hospital (KFNGH), a center-of-excellence for infection control in Riyadh, Sa