J Clin Microbiol, 2002 Jan, 40(1), 68 - 74 Emergence of penicillin-nonsusceptible Streptococcus pneumoniae invasive clones in Canada; Greenberg D et al.; Distinctive international clones of penicillin-nonsusceptible and multidrug-resistant Streptococcus pneumoniae are increasingly being reported . We investigated the spread of these clones in Canada through an active surveillance that was carried out at 11 Canadian pediatric tertiary care centers from 1991 to 1998 . All penicillin-nonsusceptible isolates were serotyped, tested for antibiotic susceptibility, and genotyped by pulsed-field gel electrophoresis (PFGE) and random amplified polymorphic DNA (RAPD) . Forty-five penicillin-nonsusceptible S . pneumoniae isolates were evaluated . Eleven serotype 9V isolates and six serotype 14 isolates displayed identical RAPD and PFGE fingerprint profiles . Twelve (70%) of these isolates were encountered in Quebec . The 9V/14 clone and the Spanish-French clone had similar PFGE fingerprint patterns . Eight isolates of serotype 23F and two isolates of serogroup 14 had the same fingerprint profiles and displayed resistance to three or more antibiotic drug classes . This clone was first detected in Calgary (Alberta) and in 1996 appeared simultaneously in various regions of Canada . This clone showed a PFGE fingerprint pattern similar to that of the Spanish-U.S . 23F clone . Our data show the emergence across Canada of two international clones of penicillin-nonsusceptible S . pneumoniae: (i) serotypes 9V and 14 related to the Spanish-French clone and (ii) the 23F Spanish-U.S . clone . The source of the first clone was in Quebec and the second international clone was probably originated from the United States . The exact reasons for the successful spread of these clones within Canada and their contribution to increased resistance to antibiotics have yet to be explored. Acad Emerg Med, 2002 Jan, 9(1), 9 - 14 A randomized clinical trial of oral versus intramuscular delivery of steroids in acute exudative pharyngitis; Marvez-Valls EG et al.; Previous study has shown that the use of intramuscular (IM) steroid leads to improved symptoms in patients with group A beta-hemolytic streptococcus (GABHS) . OBJECTIVE: To compare oral with IM steroids as an adjunct to antibiotic therapy in the treatment of acute exudative pharyngitis . The null hypothesis was that there would be no difference in effectiveness of oral versus IM steroids . METHODS: The study was a randomized, double-blind outpatient clinical trial . After consent was obtained, each patient was asked to rate his or her pain on a 10-cm numbered visual analog scale (VAS; 0-10) . All of the patients received injectable benzathine penicillin or, if allergic to penicillin, a ten-day course of polyenteric-coated erythromycin . Each patient was randomized to receive either injectable steroid plus oral placebo or injectable placebo plus oral steroid . All medications were given in the emergency department . All patients were contacted by telephone at 24 hours (first follow-up) and 48 hours (second follow-up) by one of the study investigators and asked to rate their pain based on another VAS . If their pain was not resolved by 48 hours, they were called again daily for the third to seventh day after the initial visit . The time to total resolution of the sore throat was documented . The main outcome measures were time to complete relief of pain and VAS scores . Pain medication was not controlled; however, use of pain medications and amounts were recorded . RESULTS: A total of 78 patients were initially enrolled in the study . Eight patients were excluded from the statistical analysis because of inability to follow up . A total of 70 were entered, with 35 randomized to IM steroid plus oral placebo and 35 to IM placebo plus oral steroid . There was no difference in pain scores for the oral versus IM group at first follow-up (p = 0.13) and second follow-up (p = 0.82), and in number of hours to relief of pain (p = 0.06) . Using repeated-measures analysis of variance, no difference in the effects of the two medications over time was detected (p = 0.83) . CONCLUSIONS: The results of this clinical trial suggest that oral steroid and IM steroid provide similar levels of pain relief in acute exudative pharyngitis. Med J Malaysia, 2001 Jun, 56(2), 260 - 6; quiz 267 The management of upper respiratory tract infections; Teng CL et al.; Upper respiratory tract infections are the commonest reason for consultation in primary care . Group A beta-haemolytic Streptococcus (GABHS), the most important bacterial pathogen in this condition, can be cultured from about 30% of patients, more so in children than adults . Clinical features that are predictive of positive GABHS culture are absence of cough, fever, cervical adenopathy, tonsillar enlargement and tonsillar exudate . Use of a sore throat score can help in the detection of streptococcal throat infection . Symptomatic therapies which are useful include anticholinergic, antihistamine, decongestant, humified hot air and Vitamin C . Antibiotics are universally over-prescribed in this condition as a result of high patient expectation and faulty clinical decision making . Oral Penicillin V for 10 days is the drug of choice . Effective intervention to reduce inappropriate antibiotic prescription probably require a multifaceted approach targeted at both the patients and the prescribers. Zhonghua Kou Qiang Yi Xue Za Zhi, 2001 Sep, 36(5), 385 - 7 {Experimental study of bacteriostatic activity of Chinese herbal medicines on primary cariogenic bacteria in vitro}; Wang S et al.; OBJECTIVE: To screen some Chinese herbal medicines for their inhibitory activity on cariogenic bacteria, and investigate their active ingredients, and measure their minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) . METHODS: Active components were isolated from every tested Chinese herbal medicine by means of aqueous extraction and ethanolic extraction . Berberine was purified from Coptis chinensis Fra . Disk agar diffusion method was employed in screening herbs with inhibiting effect on cariogenic bacteria . MIC and MBC were determined by broth dilution method . RESULTS: Against Streptococcus mutans Ingbritt, MBCs of Magnolia officinalis ethanolic extract, Berberine, Coptis chinensis Fra aqueous extract and Coptis chinensis Fra ethanolic extract were 0.488, 0.625, 7.800 and 1.950 g/L respectively . Against Streptococcus sobrinus 6715, MBCs of Magnolia extract, Coptis chinensis Fra ethanolic extract, Rhus chinensis Mill ethanolic extract and Phellodendron chinen ethanolic extract were 0.488, 0.625, 1.950, 3.900, 3.900 and 3.900 g/L respectively . Against Actinomyces viscosus ATCC 19246, MBCs of Berberine, Coptis chinensis Fra aqueous extract, Coptis chinensis Fra ethanolic extract, Rheum palmatum L aqueous extract and Rheum palmatum L ethanolic extract were 1.250, 3.900, 3.900, 15.600 and 31.250 g/L respectively . CONCLUSIONS: Magnolia officinalis, Coptis chinensis Fran, Rheum palmatum L aqueous extracts exhibit strong inhibition on cariogenic bacteria . Magnolia officinalis ethanolic extract has the strongest bactericidal effects on Streptococcus mutans and Streptococcus sobrinus. Zhonghua Kou Qiang Yi Xue Za Zhi, 2001 Sep, 36(5), 354 - 6 {Effects of Streptococcus sanguis on blood composition, blood pressure and cardiac dysfunction in rabbis}; Chen H et al.; OBJECTIVE: To investigate effect of streptococcus sanguis on blood cell and cardiopulmonary changes . METHODS: 133-79 strains of streptococcus sanguis (aggregation positive) were infused intravenously into rabbits . Before and 5, 10, 20, 30, 45, 60 min after infuse platelets count, leukocytes count, blood pressure and ECG were measured . RESULTS: After infused intravenously, both platelets and leukocytes count decreased remarkably (P < 0.01, n = 12) . The ECG showed ST segment depression (> 0.06 mV) . Diphasic blood pressure occurred (first hypertensive then hypotensive) . CONCLUSIONS: Streptococcus sanguis 133-79 strains in circulation system might cause myocardia ischemia, blood pressure changes, peripheral circulation platelets and leukocytes decrease remarkably. Rinsho Byori, 2001 Nov, 49(11), 1129 - 32 {Identification and epidemiologic investigation of bacteria by the Riboprinter Microbial Characterization System, the automated ribotyping system}; Iinuma Y; An automated ribotyping system, RiboPrinter Microbial Characterization System(Qualicon), was evaluated as a typing tool . Strains used in this study is as follows; 40 strains of methicillin-resistant Staphylococcus aureus (MRSA) with 40 distinct PFGE patterns, 20 MRSA from two hospital ward with suspicion of outbreaks, 53 strains of Escherichia coli including 43 strains of pathogenic E . coli, and 50 strains of Streptococcus pyogenes including 31 strains from patients with severe streptococcal disease . Typeability was 100% . Excellent result was obtained in identificating E . coli including Enterohemorrhagic E . coli O157, but poor in two species of gram positive cocci . Concerning discriminatory power, the RiboPrinter was generally less sensitive than PFGE in identifying different strains, but good correlation with strain relatedness by PFGE and antigenic classification . RiboPrinter surpassed PFGE at handling, result interpretation, and rapidity, therefore, hierarchical approach with the first pass through the RiboPrinter followed by PFGE as the occasion demands can be very useful to save labor . The RiboPrinter has the potential to be a widely useful tool in molecular epidemiology. Clin Ther, 2001 Nov, 23(11), 1889 - 900 Open-Label, parallel-group, multicenter, randomized study of cefprozil versus erythromycin in children with group A streptococcal pharyngitis/tonsillitis; Brook I et al.; BACKGROUND: Cefprozil and erythromycin are acceptable alternatives to penicillin in the treatment of pharyngitis/tonsillitis due to group A beta-hemolytic streptococcus (GABHS) . OBJECTIVE: The purpose of this trial was to determine the relative efficacy and tolerability of cefprozil and erythromycin in the treatment of pediatric pharyngitis/tonsillitis due to GABHS . METHODS: This trial compared the bacteriologic and clinical efficacy of erythromycin and cefprozil in children 2 to 12 years of age with culture-documented GABHS pharyngitis/ tonsillitis . Children who were allergic to penicillin, cefprozil, or erythromycin were excluded . Patients were prospectively randomly assigned to receive 10 days of oral therapy with either cefprozil suspension 15 mg/kg per day in 2 divided doses or erythromycin ethylsuccinate suspension 30 mg/kg per day in 3 divided doses . Primary efficacy end points were bacteriologic and clinical response 2 to 8 days after treatment ended . The frequency and severity of adverse events and their relationship to treatment were also assessed . RESULTS: A total of 199 patients were enrolled and treated (cefprozil, 99; erythromycin, 100); 12 patients in the cefprozil group and 15 in the erythromycin group were not evaluable . The GABHS eradication rate was significantly higher with cefprozil (95%) than with erythromycin (74%) (P = 0.001) . The posttreatment carrier rate was lower in the cefprozil group (5%) than in the erythromycin group (18%) (95% CI, -22.3 to -3.8) . Clinical cure rate was 90% (78/87) with cefprozil and 91% (77/85) with erythromycin (P = 0.95) (treatment group difference, -0.93; 95% CI, -9.9% to 8.0%) . The overall incidence of drug-related adverse events was not significantly different in the 2 groups (11% with cef- prozil, 18% with erythromycin) . The most common adverse events were diarrhea and vomiting . Two patients in the erythromycin group discontinued therapy because of adverse events . CONCLUSIONS: The bacteriologic eradication rate was significantly greater with cefprozil compared with erythromycin in children with pharyngitis/tonsillitis . Both cefprozil and erythromycin produced a clinical cure in >90% of patients. Biotechniques, 2001 Dec, 31(6), 1382 - 6, 1388 Rapid competitive PCR using melting curve analysis for DNA quantification; Al-Robaiy S et al.; A rapid competitive PCR method was developed to quantify DNA on the LightCycler . It rests on the quantitative information contained in the melting curves obtained after amplification in the presence of SYBR Green I . Specific hybridization probes are not required . Heterologous internal standards sharing the same primer binding sites and having different melting temperatures to the natural PCR products were used as competitors . After a co-amplification of known amounts of the competitor with a DNA-containing sample, the target DNA can be quantified from the ratio of the melting peak areas of competitor and target products . The method was developed using 16S rDNA fragments from Streptococcus mutans and E . coli and tested against existing PCR-based DNA quantification procedures . While kinetic analysis of real-time PCR is well established for the quantification of pure nucleic acids, competitive PCR on the LightCycler based on an internal standardization was found to represent a rapid and sensitive alternative DNA quantification method for analysis of complex biological samples that may contain PCR inhibitors. Nippon Jibiinkoka Gakkai Kaiho, 2001 Nov, 104(11), 1089 - 92 {A case of pediatric recurrent acute mastoiditis caused by penicillin-resistant Streptococcus pneumonia complicated by primary immunodeficiency}; Fukuiwa T et al.; Penicillin-resistant Streptococcus pneumoniae (PRSP) is a frequently detected pathogen of intractable acute otitis media and is associated with prolonged or recurrent infection . The use of antibiotics has made the incidence of secondary acute mastoiditis following acute otitis media relatively rare, but when it does occur, its severe complications may be life-threatening . We report a case of pediatric recurrent acute mastoiditis caused by PRSP in a 6-year-old boy suffering from PRSP acute mastoiditis on 4 occasions, twice undergoing simple mastoidectomy . Although we initially suspected PRSP to be the chief factor in iterative infection, immunological analysis demonstrated significantly decreased IgG and IgA antibodies in serum and the patient was diagnosed as having common variable immunodeficiency (CVID) . As the first middle ear infection occurred at the age of 6 and there was no history of upper respiratory tract infection, CVID may be the main pathological factor of recurrent mastoiditis, although infection occurred, only in the ear and did not involve other organs . This suggests that recurrent mastoiditis in the present case involved the coexistence of PRSP and CVID. Kansenshogaku Zasshi, 2001 Nov, 75(11), 977 - 80 {Acute subdural abscess due to mixed infection of Eikenella corrodens and Streptococcus constellatus}; Nakao A et al.; Eikenella corrodens is a gram-negative, facultative anaerobic rod that frequently exists as part of normal human flora in the upper respiratory tract and gastrointestinal tract . Recently, E . corrodens is reported as a rare causative agent of empyematic lesion . We report a case of 10-year-old girl with acute subdural abscess . She developed a high grade fever, swelling of the left periorbital area, right sided partial seizure and hemiplegia . Brain CT and MRI showed left parietal subdural abscess . Because intravenous antibiotic therapy was not effective enough and her neurological symptoms progressed, surgical drainage was performed in order to decompress the brain and to determine the causative agents . Through careful bacterial cultures, E . corrodens and Streptococcus constellatus were detected from the subdural abscess . After the drainage operation and a three week course of appropriate chemotherapy, the abscess completely disappeared and no sequela remained. Otolaryngol Pol, 2001, 55(3), 299 - 302 Antibiotic sensitivity of bacteria isolated in 1998 and 1999 from patients with infections of upper airways residing in Western Pomerania; Giedrys-Kalemba S et al.; Sensitivity to antibiotics of the most common pathogens isolated from the upper airways in north-west part of Poland shown significant regional variation . The rise in resistance to penicillin for Streptococcus pneumoniae (to 22%) and to macrolides for Streptococcus pyogenes, Streptococcus pneumoniae and Staphylococcus aureus was observed . No differences in sensitivity have been found between pathogens isolated from hospital and ambulatory patients. J Mol Microbiol Biotechnol, 2002 Jan, 4(1), 101 - 10 A XerD recombinase with unusual active site motifs in Streptococcus pneumoniae; Reichmann P et al.; XerD belongs to the site specific recombinases of the integrase family of proteins that catalyze recombination events via a phosphotyrosine intermediate . Sequence alignments and crystal structure resolution of E . coli XerD and related enzymes demonstrated the importance of four conserved amino acids R-H-R-H that are spaced along the C-terminal domain in addition to a conserved K and the active site Y, all of which have been implicated in catalysis . The deduced amino acid sequence of the putative S . pneumoniae XerD contained three unique replacements at the conserved positions resulting in L-Q-R-L; moreover, the active site Y was the penultimate amino acid residue, and the extreme C-terminal region suggested to be involved in interaction of E . coli XerD with XerC was lacking . Severe growth defects in a loss-of-function xerD mutant are consistent with an important in vivo function of the S . pneumoniae XerD protein . Highly related xerD genes with similar unusual amino acid replacements were found in S . mitis, S . mutans and S . pyogenes but not in other Gram-positive bacteria, although the genetic environment was very similar in many species . There are at least another four genes in the S . pneumoniae KNR_7/87 genome encoding Xer related peptides, one of which was identified as the xerC homologue . The xerD and xerC genes were present in a sample of 20 S . pneumoniae strains whereas the other xer genes appear to be absent in some of the strains and are more closely related to integrases of phage and transposon origin. Am J Dent, 2000 Sep, 13(Spec No), 14C - 17C Caries inhibition efficacy of an antiplaque/antigingivitis dentifrice; Yu D et al.; PURPOSE: To evaluate the efficacy of a fluoride dentifrice containing a fixed combination of essential oils (Thymol, Menthol, Eucalyptol, and Methyl Salicylate) in preventing caries in Sprague Dawley rats . MATERIALS AND METHODS: The dentifrice contains 0.76% sodium monofluorophosphate (SMFP) as the fluoride source and a silica abrasive system . A fluoride-free placebo and a clinically proven USP dentifrice reference standard for SMFP/silica were included as controls . Three groups of 45 SDV-free Sprague Dawley weanlings were infected by a cariogenic strain of Streptococcus sobrinus and fed cariogenic diet NIH 2000 ad libitum . Animals were treated twice daily (once on weekends) with the assigned dentifrice using a cotton-tipped applicator, for 5 wks, after which they were terminated and caries scored using Larson's modification of the Keyes method . RESULTS: Analyses of variance were used to compare inter-group means, the total E lesion score was the primary efficacy variable . Compared with the fluoride-free vehicle control, the experimental dentifrice and USP reference standard dentifrice produced a statistically significant reductions of 18.3% and 12.2% respectively for total caries score (P<0.001) . Compared with the clinically tested USP positive control dentifrice, the experimental dentifrice produced a statistically significant reduction in the total caries score of 6.9% (P=0.028) . The results of this study show that 1) both the new dentifrice containing essential oils and USP dentifrice are statistically significantly effective in reducing caries in the rat model, 2) the anticaries activity of the SMFP dentifrice is not adversely affected with the addition of essential oils. Microbiol Immunol, 2001, 45(10), 699 - 707 Anti-fibrin antibody binding in valvular vegetations and kidney lesions during experimental endocarditis; Yokota M et al.; In Streptococcus sanguinis (sanguis) induced experimental endocarditis, we sought evidence that the development of aortic valvular vegetation depends on the availability of fibrin . Endocarditis was induced in New Zealand white rabbits by catheter placement into the left ventricle and inoculation of the bacteria . Fibrin was localized in the developing vegetation with 99mTechnetium (Tc)-labeled anti-fibrin antibody one or three days later . When rabbit anti-fibrin antibody was given intravenously on day 1, the mass of aortic valvular vegetation was significantly reduced at day 3; infusion of non-specific rabbit IgG showed no effect . The 99mTc-labeled anti-fibrin antibody also labeled kidneys that showed macroscopic subcapsular hemorrhage . To learn if the deposition of fibrin in the kidneys was a consequence of endocarditis required a comparison of farm-bred and specific pathogen-free rabbits before and after the induction of endocarditis . Before induction, the kidneys of farm-bred rabbits were labeled, but specific pathogen-free rabbits were free of labeling and signs of macroscopic hemorrhage . After 3 days of endocarditis, kidneys of 10 of 14 specific pathogen-free rabbits labeled with 99mTc-labeled anti-fibrin antibody and showed hemorrhage . Kidney lesions were suggested to be a frequent sequellae of S . sanguinis infective endocarditis . For the first time, fibrin was shown to be required for the continued development of aortic valvular vegetations. J Chemother, 2001 Oct, 13(5), 541 - 5 Streptococcus pneumoniae penicillin resistance in Turkey; Gur D et al.; Resistance of Streptococcus pneumoniae (750) to penicillin, erythromycin, chloramphenicol and trimethoprim/sulfamethoxazole isolated in 4 Turkish hospitals between 1996 and 1999 was evaluated according to year of isolation, patients' age groups and specimen . Penicillin susceptibility was determined by E-test strips and the other antibiotics were tested by disk diffusion test following the NCCLS guidelines in each center . Overall high and intermediate resistance to penicillin was 3% and 29%, respectively . There was a significant difference (p<0.001) between the centers with regard to penicillin resistance . However, there was no significant increase in resistance by year . Penicillin resistance varied significantly among children and adults (36% versus 25%) and according to the specimen . Highest rate of penicillin resistance was observed in respiratory specimens (36%) followed by ear exudates (33.5%) . In blood isolates, resistance to penicillin was 28.6% . Overall resistance to erythromycin was 8%, to chloramphenicol 5% and to trimethoprim-sulfamethoxazole 47% . Although overall penicillin resistance in these Turkish S . pneumoniae isolates is high, resistance rates vary in each center and have not increased from 1996 to 1999. J Chemother, 2001 Oct, 13(5), 535 - 40 Time-kill evaluation of antimicrobial regimens against clinical isolates of penicillin-resistant Streptococcus pneumoniae; Banon Arias R et al.; The rate of penicillin-resistant Streptococcus pneumoniae isolates in Spain is high . At present, penicillin and ceftriaxone are two drugs chosen for treating serious infections . In this study the bactericidal activity of four antimicrobial regimens against ten clinical isolates of S . pneumoniae (five with an intermediate resistance to penicillin and five highly resistant ones), was determined by means of kill kinetics studies using either penicillin, or ceftriaxone, in combination with vancomycin, or fosfomycin . The concentrations of the antimicrobial regimens (MICs 4x, 1x and 1/4x) were within possible physiological levels . While the combinations of penicillin, or ceftriaxone, plus vancomycin showed a significant increase in bactericidal activity, the bacterial reductions obtained in combination with fosfomycin were greater, achieving synergistic effects . These results suggest that in vivo trials with a regimen composed of ceftriaxone and fosfomycin would be worthwhile. Scand J Infect Dis, 2001, 33(11), 854 - 6 Non-tropical thoraco-abdominal pyomyositis caused by group A streptococcus in an immunocompetent adult; Cherry C et al.; We present a case of group A streptococcal pyomyositis of the thoraco-abdominal wall of an immunocompetent adult . This diagnosis was made when soft tissue swelling was seen on chest X-ray . Complete recovery followed drainage of the collection and short-course i.v . penicillin . The importance, diagnosis and treatment of pyomyositis are outlined. Scand J Infect Dis, 2001, 33(11), 815 - 7 Dental caries is common in Finnish children infected with Helicobacter pylori; Kolho KL et al.; Childhood factors such as low socioeconomic status are risk factors for Helicobacter pylori infection and Streptococcus mutans-related dental caries . We examined whether H . pylori infection and dental caries are present today in the same group of children examined previously . We reviewed the public dental health service files of 21 H . pylori-positive children (upper gastrointestinal endoscopy at a median age of 13.5 y) and 27 H . pylori-negative children (endoscopy at a median age of 12.5 y) examined during 1995-98 at the Helsinki University Central Hospital, Finland . All H . pylori-positive children had experienced dental caries in their primary or permanent teeth or in both whereas among H . pylori-negative children the respective proportion was 70% (p < 0.01) . At the age of 7 y, 18% (3/17) of the H . pylori-positive children had experienced caries in permanent teeth as compared to 0% among H . pylori-negative children (0/24; p < 0.05) . At the age of 12 y, H . pylori-positive children had more decayed, missing or filled permanent teeth than H . pylori-negative children (80% vs . 38%; p < 0.05) . Although a causal relationship between H . pylori and dental caries is unlikely, it is possible that H . pylori-infected children have an increased risk of other health problems, such as dental caries, for which proper treatment is needed. J Med Assoc Thai, 2001 Jul, 84(7), 995 - 9 Spontaneous bacterial peritonitis, causes and antibiotic usage in Srinagarind hospital; Lolekha P et al.; Spontaneous bacterial peritonitis (SBP) is a common and often fatal complication occurring in cirrhotic patients with ascites . It is defined as an infection of the ascitic fluid in the absence of any obvious intra-abdominal source . This study was a descriptive retrospective study that examined signs and symptoms of SBP, prevalence, result of the culture and antibiotic susceptibility of the organisms and outcome of antibiotic treatment, especially to ampicillin-aminoglycoside . Data were collected from inpatient medical records at Srinagarind Hospital between 1993 and 1997 . Forty-four patients with 54 episodes of SBP were included in this study . The results revealed that SBP commonly occurred in cirrhotic patients . Presenting symptoms of SBP were fever, abdominal pain and abdominal distension, respectively . Signs of SBP were ascites and rebound abdominal tenderness . Forty-three per cent of ascitic fluid cultures were positive for bacteria E . coli (30.4%), Streptococcus spp (26.1%) and Klebsiella spp (13.0%) were the most common causes of SBP which were similar to other studies . Ampicillin plus an aminoglycoside were mostly often used in this study; in only 15.8 per cent of patients did the antibiotics need to be changed . Mortality rate in this group was not increased after antibiotic was changed. J Med Assoc Thai, 2001 Jul, 84(7), 1056 - 8 Microaerophilic streptococcus meningoencephalitis: report of a case; Chotmongkol V et al.; A 64-year-old woman who presented with acute meningoencephalitis was reported . Cerebrospinal fluid (CSF) revealed polymorphonuclear pleocytosis with gram-positive cocci . Blood and CSF grew microaerophilic streptococcus . The patient was treated with intravenous penicillin G and chloramphenicol for 2 weeks and recovered without sequela . There was no evidence of any focus of infection prone to the development of this infection. Microb Drug Resist, 2001 Fall, 7(3), 277 - 87 Prevalence of antimicrobial resistance in Streptococcus pneumoniae circulating in Italy: results of the Italian Epidemiological Observatory Survey (1997-1999); Marchese A et al.; The Italian Epidemiological Observatory (IEO), a surveillance program supported by the SmithKline Foundation, analyzed the susceptibility of 2,664 community-acquired respiratory Streptococcus pneumoniae derived from over 50 clinical microbiology laboratories during 1997-1999, against 21 antibiotics adopting a quantitative methodology . Throughout these years, total penicillin resistance varied from 14.3% to 10.2% . High-level resistance has remained stable, ranging from 3.8% to 4.1%, while a decrease in low-level resistance (from 10.3% to 6.1%) has been recorded . Lack of susceptibility to macrolides ranged from 29.1% in 1997 to 25.5% in 1999 . Similar figures have also been observed with tetracycline and co-trimoxazole (rates of resistance around 30%) . As expected, large geographical variations in resistance rates were found for all drugs . Amoxicillin and amoxicillin-clavulanate were 100% active on penicillin-intermediate isolates . Injectable third-generation cephalosporins and carbapenems were also capable of inhibiting a large proportion of these microorganisms . Rifampin was the most potent non-beta-lactam compound tested . In contrast to the situation prevailing elsewhere, in Italian children (aged 0-5 years) presenting with respiratory conditions, the total rate of penicillin resistance (3%) was lower than that shown by the adult population (10.9%) . However, lack of susceptibility to macrolides, tetracycline, and cotrimoxazole (35%, 41%, 44%) was more incident in pediatric than in adult patients (25%, 26%, 28% respectively) . Strains recovered from blood in 1999 (67) were much more susceptible to penicillin (98.5%) than respiratory pneumococci (89.8%), whereas macrolides, tetracycline, and cotrimoxazole were consistently less active (75%, 67%, 64%). Microb Drug Resist, 2001 Fall, 7(3), 213 - 22 Molecular characterization of the pneumococcal teichoic acid phosphorylcholine esterase; de las Rivas B et al.; A search to identify proteins with high affinity for choline-containing pneumococcal cell walls (choline-binding proteins) has permitted the localization, cloning, sequencing, and overexpression of a gene (pce), coding for a protein (Pce) that liberates phosphorylcholine from purified cell walls of Streptococcus pneumoniae . The pce gene of the pneumococcal strain R6 encodes a protein of 627 amino acids with a predicted Mr of 72,104 . Pce can remove a maximum of 20% phosphorylcholine residues from the cell wall teichoic acid . In silico analysis of Pce shows a modular organization of the enzyme where the choline-binding domain, involved in cell wall substrate recognition, and the catalytic domain are located at the carboxy- and amino-terminal moieties of the protein, respectively . Remarkably, a long tail of 85 amino acids follows the carboxy-terminal domain, a structural feature that had not been described for the published choline-binding proteins . The carboxy-terminal moiety of Pce is assembled by 10 repeated motifs, and the protein has also a cleavable signal peptide of 25 amino acids that renders after its cleavage a mature protein of 69,426 Da (602 amino acids) . The pce gene has been expressed in Escherichia coli, and Pce was active when assayed on pneumococcal walls . We have also found that the signal peptide of Pce was functional in E . coli . Biochemical analysis suggested that Pce is the teichoic acid phosphorylcholine esterase of S . pneumoniae that had been biochemically characterized previously . Construction of two pce pneumococcal mutants (R6D and M31D) by insertion-duplication mutagenesis revealed that these mutants grew at a doubling-time similar to those of the parental strains of the wild-type R6 and the lytA-mutant M31, respectively . R6D and M31D were morphologically indistinguishable from the parental strains when whole-mounted cells were observed under the electron microscope and exhibited levels of competence for genetic transformation slightly lower than those reported for R6 and M31. J Infect Dis, 2002 Jan 1, 185(1), 123 - 6 Epub 2001 Nov 30. Roles of interleukin-6 and macrophage inflammatory protein-2 in pneumolysin-induced lung inflammation in mice; Rijneveld AW et al.; Pneumolysin (PLY), a toxin synthesized by Streptococcus pneumoniae, is an important virulence factor in pneumococcal disease . This study evaluated the effects of PLY in lungs of mice . Intranasal inoculation with PLY was associated with a dose-dependent influx of polymorphonuclear leukocytes (PMNL) in bronchoalveolar lavage fluid (BALF) and increased concentrations of interleukin (IL)-6, macrophage inflammatory protein (MIP)-2, and KC in BALF . PLY mutants with either reduced cytolytic activity or reduced cytolytic and complement-activating activities were less potent in inducing PMNL recruitment to the lung (P<.05), which suggests that PLY cytolytic activity is very important for the inflammatory response . IL-6 and MIP-2 also played a role in PLY-induced PMNL recruitment; this response was partially diminished in IL-6 gene-deficient mice and in mice treated with anti-MIP-2 antiserum . PLY may play an important role in the induction of an inflammatory response in the pulmonary compartment in the early phase of pneumococcal pneumonia. J Infect Dis, 2002 Jan 1, 185(1), 91 - 7 Epub 2001 Dec 14. The role of interferon-gamma in murine pneumococcal pneumonia; Rijneveld AW et al.; To determine the role of interferon (IFN)-gamma in pneumonia, IFN-gamma receptor-deficient (IFN-gamma R(-/-)) and 129/Sv (wild-type {wt}) mice were inoculated intranasally with Streptococcus pneumoniae . Although mortality did not differ between the groups 48 h after inoculation, IFN-gamma R(-/-) mice had significantly fewer pneumococci in their lungs than the wt mice . Similarly, IFN-gamma(-/-) mice had fewer colony-forming units in lungs than wt mice . The relatively increased resistance of IFN-gamma R(-/-) mice was not related to favorable effects on defense mechanisms known to contribute to antibacterial immunity-that is, the neutrophilic influx was reduced and the cytokine and nitric oxide levels were similar or lower in IFN-gamma R(-/-) mice . In contrast, mice treated with anti-IFN-gamma did not demonstrate a consistently altered bacterial outgrowth, compared with mice treated with a control antibody . These data suggest that endogenous IFN-gamma, despite its protective role in defense against intracellular pathogens, does not serve a protective role during pneumococcal pneumonia. Pediatr Res, 2002 Jan, 51(1), 106 - 11 Polymorphisms in the cell wall-spanning domain of the C protein beta-antigen in clinical Streptococcus agalactiae isolates are caused by genetic instability of repeating DNA sequences; Berner R et al.; The C protein alpha- and beta-antigens are immunodominant components of the surface of Streptococcus agalactiae, the most frequent cause of neonatal sepsis . Both proteins are thought to contribute significantly to virulence of S . agalactiae . They are mainly expressed by serotypes Ia, Ib, and II . The C protein beta-antigen (Cbeta-protein) binds to the Fc portion of human IgA and seems to be of importance in bacterial resistance to mucosal immune defense mechanisms . In this study, PCR analysis of S . agalactiae isolates obtained from 189 neonates and 112 pregnant women revealed the presence of the Cbeta-protein gene in 19% and 22% of the isolates, respectively . Size polymorphisms of the PCR products within the gene region encoding the cell wall-spanning domain indicated a high degree of genetic variability . Thirteen different variants of the amplified region were differentiated among the 60 Cbeta-protein-positive isolates by sequence analysis . In all variants, the polymorphisms were caused by insertions and deletions of repetitive DNA elements that did not alter the open reading frame . Comparison of the Cbeta-protein gene polymorphisms showed a significantly higher rate of isolates carrying deletions >50 bp in serotype Ib than in serotype II isolates (p = 0.001); this was also true for neonatal isolates analyzed separately (p = 0.01) . Neonatal isolates carried a higher rate of large deletions when compared with maternal isolates; this difference, however, did not reach statistical significance (p = 0.08) . We hypothesize that polymorphisms in the cell wall-spanning domain of the Cbeta-protein are of functional relevance with regard to maternofetal transmission of the pathogen. Dev Comp Immunol, 2002 Apr, 26(3), 257 - 69 Activation of nonspecific cytotoxic cells (NCC) with synthetic oligodeoxynucleotides and bacterial genomic DNA: binding, specificity and identification of unique immunostimulatory motifs; Oumouna M et al.; We have analyzed the effects of synthetic oligodeoxynucleotides (sODNs) and bacterial DNA (bDNA) on the in vitro activation of NCC . Teleost NCC recognition of DNA appeared to differ from that which occurs in higher vertebrates . NCC contain at least two different receptor specificities for DNA . Both oligodeoxyguanosine 20-mers (dG20) and 5'-TGCTGCTTGTGCTTGTGCTT-3' (4GC-2T) bound specifically to NCC . The existence of different receptor specificities was indicated by reciprocal cold target inhibition experiments . dG20 competed with 4GC-2T binding but sODNs composed of GpC or CpG nests did not compete with recognition by NCC of the dG20 . ODN binding by NCC primarily depended on the presence of GpC or CpG nests with a preference for -G- serving as the anchor nucleotide . Secondarily, and similar to models of ODN activation in mammals, palindrome sequences of pu-pu-CpG-py-py activated NCC cytotoxicity . Additional analysis of the requirements for ODN activation indicated that guanosine could not substitute for adenosine as a purine spacer and that CpG motifs containing flanking thymidine (i.e.-GTCpGTT-) augmented the activity of the sODN containing this flanking base . Other evidence for the participation of both G and C in the recognition of specific nucleotides by NCC was that poly-dC20, dA20 or dT20 had no activating properties . Methylation of all cytosine nucleotides within an ODN abrogated activation . A canonical ODN motif of 5'-C/AT/AGCTT-3' can now be suggested for teleosts . Additional studies were done to examine the effects of in vitro treatment of NCC with bDNA . bDNA from three different disease isolates of Streptococcus iniae activated NCC cytotoxicity . Treatment of the bDNA with DNase abrogated the enhancement of cytotoxicity . Also, treatment of NCC with eukaryotic DNA had no effects on cytotoxicity . These studies suggested that NCC recognize bacterial nonmethylated DNA . The consequences of these interactions may be increased innate and acquired anti-bacterial immunity. Obstet Gynecol, 2001 Dec, 98(6), 1075 - 9 Maternal and transplacental pharmacokinetics of cefazolin; Fiore Mitchell T et al.; OBJECTIVE: To evaluate the intrapartum pharmacokinetics of cefazolin, including delivery to amniotic fluid (AF) and fetal compartments, and to ascertain that adequate cefazolin concentrations are attained to exceed the mean concentration inhibiting 90% (MIC(90)) of group B streptococcus strains . METHODS: Cefazolin (1 g) was administered intravenously at five separate time intervals (0.5, 1, 2, 4, and 6 hours) before elective cesarean at term to 26 women with intact membranes and with no significant infections or cardiovascular, liver, or renal disease . Samples of maternal blood, cord blood, and AF were obtained at the time of delivery . Exact collection times relative to cefazolin infusion were noted . Amniotic fluid contaminated with blood or meconium was excluded . Cefazolin concentration was measured by high-pressure liquid chromatography . RESULTS: All maternal and cord plasma cefazolin levels, except one, were above the MIC(90) for Streptococcus agalactiae (group B streptococcus) . For AF, all cefazolin levels, except two, were above the MIC(90) . CONCLUSIONS: Cefazolin concentrations greater than or equal to the MIC(90) for group B streptococcus were attained in nearly all maternal, fetal, and AF samples . This information, together with the knowledge that there is rare resistance of group B streptococcus to cefazolin, supports the use of cefazolin as a better alternative than clindamycin or erythromycin for group B streptococcus prophylaxis in patients with a nonanaphylactic penicillin allergy. Am J Med, 2001 Dec 17, 111 Suppl 9A, 13S - 18S; discussion 36S-38S Pharmacodynamic profiling of levofloxacin and gatifloxacin using Monte Carlo simulation for community-acquired isolates of Streptococcus pneumoniae; Nicolau DP et al.; In vitro and in vivo models of infection suggest that the area under the concentration-time curve (AUC): minimum inhibitory concentration (MIC) ratio is the pharmacodynamic parameter that is most predictive of bactericidal activity for the fluoroquinolones . Additionally, this parameter has also been correlated with clinical outcomes in humans with respiratory tract infection . Despite these defined relationships, broad-scale application of these principles in the section of optimal therapy in the clinical arena has been restricted by the imprecise estimates of drug exposures (ie, AUC:MIC ratio) in the infected population . In an effort to best describe the known variability in the pharmacokinetic and susceptibility profile of agents of interest, Monte Carlo simulation has been employed to assess the probability of attaining the desired AUC:MIC ratio . In this report Monte Carlo simulation was used to estimate the probability of attaining various target AUC:MIC ratios using AUC values from patients treated with either gatifloxacin or levofloxacin and the in vitro potency of the compounds as assessed in 881 clinical isolates of Streptococcus pneumoniae isolated from outpatients . Using a simulated patient population of 5,000, the median AUC:MIC ratios were 144 and 50 for gatifloxacin and levofloxacin, respectively . The probability of attaining AUC:MIC ratios of 30, 40, 65, 100, and 125 for gatifloxacin were 99%, 95%, 85%, 68%, and 60%, respectively . For levofloxacin, similar dynamic hit rates were 82%, 61%, 35%, 17%, and 12% over the range of target values . Regardless of the optimal ratio selected, gatifloxacin had a higher probability of achieving the AUC:MIC target than did levofloxacin . Simulations of this type can assist in the decision process surrounding the choice of optimal therapies based on our current understanding of antimicrobial pharmacodynamic principles. Acta Crystallogr D Biol Crystallogr, 2002 Jan, 58(Pt 1), 165 - 6 Epub 2001 Dec 21. Crystallization and preliminary crystallographic analysis of the soluble alpha-glycerophosphate oxidase from Streptococcus sp; Finnerty CM et al.; Single crystals of soluble FAD-dependent alpha-glycerophosphate oxidase (GlpO) from Streptococcus sp . were obtained using the microseeding and hanging-drop vapor-equilibrium methods . Synchrotron X-ray radiation was used to collect diffraction data to 2.4 A resolution from these crystals . GlpO shares >30% identity with several bacterial and mitochondrial alpha-glycerophosphate dehydrogenases, although the GlpOs contain a 50-52-residue unique insert that appears to be important for efficient flavin reduction . The present work is an important first step in determining the structure of GlpO, which should provide insights on the function of this interesting flavoenzyme and its homologs. J Immunol, 2002 Jan 1, 168(1), 372 - 8 IL-18 improves the early antimicrobial host response to pneumococcal pneumonia; Lauw FN et al.; To determine the role of endogenous IL-18 during pneumonia, IL-18 gene-deficient (IL-18(-/-)) mice and wild-type (WT) mice were intranasally inoculated with Streptococcus pneumoniae, the most common causative agent of community-acquired pneumonia . Infection with S . pneumoniae increased the expression of IL-18 mRNA and was associated with elevated concentrations of both precursor and mature IL-18 protein within the lungs . IL-18(-/-) mice had significantly more bacteria in their lungs and were more susceptible for progressing to systemic infection at 24 and 48 h postinoculation . Similarly, treatment of WT mice with anti-IL-18 was associated with enhanced outgrowth of pneumococci . In contrast, the clearance of pneumococci from lungs of IL-12(-/-) mice was unaltered when compared with WT mice . Furthermore, anti-IL-12 did not influence bacterial clearance in either IL-18(-/-) or WT mice . These data suggest that endogenous IL-18, but not IL-12, plays an important role in the early antibacterial host response during pneumococcal pneumonia. J Bacteriol, 2002 Jan, 184(2), 610 - 3 Identification of a protein that inactivates the competence-stimulating peptide of Streptococcus pneumoniae; Berge M et al.; Competence for genetic transformation of Streptococcus pneumoniae is a transient physiological property inducible by a competence-stimulating peptide (CSP) . A 68-kDa CSP-inactivating protein was previously obtained following lithium chloride (LiCl) extraction . By the same protocol, a CSP-inactivating protein was purified and identified by matrix-assisted laser desorption ionization-time of flight mass spectrometry as an endopeptidase, PepO . Analysis of a pepO mutant provided no support for the hypothesis that PepO participates in competence regulation . To reconcile in vitro and in vivo data, we suggest that LiCl treatment results in the release of intracellular molecules, including PepO. J Bacteriol, 2002 Jan, 184(2), 577 - 83 Streptococcus pneumoniae capsule biosynthesis protein CpsB is a novel manganese-dependent phosphotyrosine-protein phosphatase; Morona JK et al.; The first four genes of the capsule locus (cps) of Streptococcus pneumoniae (cpsA to cpsD) are common to most serotypes . We have previously determined that CpsD is an autophosphorylating protein-tyrosine kinase, demonstrated that CpsC is required for CpsD tyrosine-phosphorylation, and shown that CpsB is required for dephosphorylation of CpsD . In the present study we show that CpsB is a novel manganese-dependent phosphotyrosine-protein phosphatase that belongs to the PHP (polymerase and histidinol phosphatase) family of phosphoesterases . We also show that an S . pneumoniae strain with point mutations in cpsB, affecting one of the conserved motifs of CpsB, is unencapsulated and appears to be morphologically identical to a strain in which the cpsB gene had been deleted. J Bacteriol, 2002 Jan, 184(2), 433 - 43 Diversity of Tn4001 transposition products: the flanking IS256 elements can form tandem dimers and IS circles; Prudhomme M et al.; We show that both flanking IS256 elements carried by transposon Tn4001 are capable of generating head-to-tail tandem copies and free circular forms, implying that both are active . Our results suggest that the tandem structures arise from dimeric copies of the donor or vector plasmid present in the population by a mechanism in which an IS256 belonging to one Tn4001 copy attacks an IS256 end carried by the second Tn4001 copy . The resulting structures carry abutted left (inverted left repeat {IRL}) and right (inverted right repeat {IRR}) IS256 ends . Examination of the junction sequence suggested that it may form a relatively good promoter capable of driving transposase synthesis in Escherichia coli . This behavior resembles that of an increasing number of bacterial insertion sequences which generate integrative junctions as part of the transposition cycle . Sequence analysis of the IRL-IRR junctions demonstrated that attack of one end by the other is largely oriented (IRL attacks IRR) . Our experiments also defined the functional tips of IS256 as the tips predicted from sequence alignments, confirming that the terminal 4 bp at each end are indeed different . The appearance of these multiple plasmid and transposon forms indicates that care should be exercised when Tn4001 is used in transposition mutagenesis . This is especially true when it is used with naturally transformable hosts, such as Streptococcus pneumoniae, in which reconstitution of the donor plasmid may select for higher-order multimers. J Antimicrob Chemother, 2002 Jan, 49(1), 173 - 6 Fluoroquinolone resistance among clinical isolates of Streptococcus pneumoniae belonging to international multiresistant clones; McGee L et al.; Twenty-nine fluoroquinolone (FQ)-resistant clinical isolates of Streptococcus pneumoniae from a collection of isolates from the Alexander Project (1992-1997) and a study from Northern Ireland were identified on the basis of ofloxacin MICs > or = 4 mg/L . DNA fingerprint analyses using BOX-fingerprinting and pulsed-field gel electrophoresis revealed serotype 9V and 23F high-level FQ-resistant strains indistinguishable from the pandemic Spain(23F)-1 and Spain(9V)-3 clones, the type strains of which are low-level resistant or susceptible to the fluoroquinolones. J Antimicrob Chemother, 2002 Jan, 49(1), 113 - 9 Comparative pharmacodynamics of azithromycin and roxithromycin with S . pyogenes and S . pneumoniae in a model that simulates in vitro pharmacokinetics in human tonsils; Firsov AA et al.; Most macrolides penetrate and persist in peripheral tissues, irrespective of plasma concentrations . For this reason, comparative pharmacodynamics of macrolides might be better based on tissue rather than plasma pharmacokinetics . The present study compares the antimicrobial effects of azithromycin and roxithromycin on Streptococcus pyogenes and Streptococcus pneumoniae using in vitro simulations of steady-state pharmacokinetics in human tonsils expected after a third 500 mg dose of azithromycin administered once a day and after a sixth 150 mg dose of roxithromycin administered twice a day . Clinical isolates of S . pyogenes and S . pneumoniae (MICs 0.12 and 0.47 mg/L of azithromycin, and 0.15 and 0.60 mg/L of roxithromycin, respectively) were used . More pronounced antistreptococcal effects were observed with azithromycin than with roxithromycin . Despite similar rates of initial killing of S . pyogenes and S . pneumoniae, the respective 12 h areas between the control growth curve and the time-kill curve of antibiotic-exposed bacteria (ABBCs) were 22% and 36% greater with azithromycin than roxithromycin . Moreover, with azithromycin, viable bacterial counts reached the theoretically achievable limit of detection (10 cfu/mL) 8-10 h after drug administration, with no regrowth within 48 h . In contrast to azithromycin, S . pyogenes and S . pneumoniae exposed to roxithromycin regrew 26 and 6 h, respectively, after initial reduction of the starting inoculum . Further in vitro simulations of tissue pharmacokinetics might be useful for pharmacodynamic comparisons among other macrolides. Clin Cancer Res, 2001 Dec, 7(12), 4182 - 94 Identification of a novel membrane protein, HP59, with therapeutic potential as a target of tumor angiogenesis; Fu C et al.; CM101, a polysaccharide isolated from the culture medium of Group B streptococcus, a neonatal pathogen, targets pathological angiogenesis and inhibits tumor growth in mice and humans . CM101 also targets neonatal lung and adult sheep lung endothelial cells . A gene encoding a transmembrane protein that interacts with CM101 was isolated from a sheep lung endothelial cell cDNA library . The gene, termed sp55, encodes a 495-amino acid polypeptide . COS-7 cells transfected with a vector containing sp55 express the SP55 protein-bound CM101 in a concentration-dependent manner . Stably transfected CHO cells also bound CM101 . The corresponding human gene, hp59, was isolated from a human fetal lung cDNA library and had a predicted identity to SP55 of 86% over 495 amino acids . HP59 protein was shown by immunohistochemistry to be present in the pathological tumor vasculature of the lung, breast, colon, and ovary, but not in the normal vasculature, suggesting that the protein may be critical to pathological angiogenesis . The hp59 gene and/or the HP59 protein was not expressed in a variety of normal tissues, but was significantly expressed in human fetal lung, consistent with the pathophysiology of Group B streptococcus infections in neonates . Mice immunized with HP59 and SP55 peptides showed significant attenuation of tumor growth . Immunization effectively inhibited both the tumor angiogenesis and vasculogenesis processes, as evidenced by lack of both HP59- and CD34-positive vessels . These results and the immunohistochemistry data suggest a therapeutic potential for the CM101 target protein HP59 both as a drug target and as a vaccine against pathoangiogenesis. Antimicrob Agents Chemother, 2002 Jan, 46(1), 125 - 31 Diversity of ribosomal mutations conferring resistance to macrolides, clindamycin, streptogramin, and telithromycin in Streptococcus pneumoniae; Canu A et al.; Mechanisms of resistance were studied in 22 macrolide-resistant mutants selected in vitro from 5 parental strains of macrolide-susceptible Streptococcus pneumoniae by serial passage in various macrolides (T . A . Davies, B . E . Dewasse, M . R . Jacobs, and P . C . Appelbaum, Antimicrob . Agents Chemother., 44:414-417, 2000) . Portions of genes encoding ribosomal proteins L22 and L4 and 23S rRNA (domains II and V) were amplified by PCR and analyzed by single-strand conformational polymorphism analysis to screen for mutations . The DNA sequences of amplicons from mutants that differed from those of parental strains by their electrophoretic migration profiles were determined . In six mutants, point mutations were detected in the L22 gene (G95D, P99Q, A93E, P91S, and G83E) . The only mutant selected by telithromycin (for which the MIC increased from 0.008 to 0.25 microg/ml) contained a combination of three mutations in the L22 gene (A93E, P91S, and G83E) . L22 mutations were combined with an L4 mutation (G71R) in one strain and with a 23S rRNA mutation (C2611A) in another strain . Nine other strains selected by various macrolides had A2058G (n = 1), A2058U (n = 2), A2059G (n = 1), C2610U (n = 1), and C2611U (n = 4) mutations (Escherichia coli numbering) in domain V of 23S rRNA . One mutant selected by clarithromycin and resistant to all macrolides tested (MIC, >32 microg/ml) and telithromycin (MIC, 4 microg/ml) had a single base deletion (A752) in domain II . In six remaining mutants, no mutations in L22, L4, or 23S rRNA could be detected. Antimicrob Agents Chemother, 2002 Jan, 46(1), 119 - 24 Prevalence of single mutations in topoisomerase type II genes among levofloxacin-susceptible clinical strains of Streptococcus pneumoniae isolated in the United States in 1992 to 1996 and 1999 to 2000; Davies TA et al.; Levofloxacin resistance in Streptococcus pneumoniae is rare, requiring at least two mutations in the quinolone resistance-determining region (QRDR) of topoisomerase IV and DNA gyrase . The prevalence of single QRDR mutations in these genes is unknown . Of 9,438 levofloxacin-susceptible pneumococci from the TRUST 4 surveillance study (1999-2000), 528 strains (MICs of 0.5 to 2.0 microg/ml) were selected for analysis . For comparison, 214 levofloxacin-susceptible strains (MICs of 0.5 to 1 microg/ml) isolated between 1992 and 1996 were analyzed . Oligonucleotide probe assay and DNA sequencing were used to detect QRDR mutations leading to changes at Ser79 and Asp83 in ParC, Ser81 in GyrA, and Asp435 in ParE, the most frequently found substitutions among levofloxacin-resistant strains . Among the 1992 to 1996 isolates only one strain (levofloxacin MIC, 1 microg/ml) had a mutation (Ser79 to Phe in ParC) . No single mutations were found among 270 TRUST 4 strains with levofloxacin MICs of 0.5 microg/ml . Among 244 strains for which levofloxacin MICs were 1 microg/ml, 15 strains (6.1%) had a parC mutation and 3 strains (1.2%) had a parE mutation . Of 14 strains for which levofloxacin MICs were 2 microg/ml, 10 strains (71%) had a parC mutation; no parE mutations were found . No gyrA mutations were detected . It was estimated that 4.5% of the 9,438 levofloxacin-susceptible TRUST 4 isolates (MICs, < or =0.06 to 2 microg/ml) had a single parC or parE QRDR mutation . Although there has been an increase in the prevalence of single-step mutants, the increase may have been overestimated due in part to differences in geographical distribution for the two sets of isolates. Antimicrob Agents Chemother, 2002 Jan, 46(1), 69 - 74 Pharmacodynamics of gatifloxacin against Streptococcus pneumoniae in an in vitro pharmacokinetic model: impact of area under the curve/MIC ratios on eradication; Lister PD; Previous studies have demonstrated that fluoroquinolone area under the curve (AUC)/MIC ratios of 30 to 50 are sufficient to eradicate pneumococci from in vitro pharmacokinetic models (IVPMs) . However, more systematic studies of the impact of AUC/MIC ratios on the antipneumococcal activities of fluoroquinolones are needed . In the present study, a two-compartment IVPM was used to evaluate the impact of AUC/MIC ratios on the pharmacodynamics of gatifloxacin against four strains of Streptococcus pneumoniae . Gatifloxacin MICs were 0.4 to 1 microg/ml, whereas levofloxacin MICs were 1.8 to 3.2 microg/ml . Since both peak concentration/MIC (peak/MIC) and AUC/MIC ratios affect fluoroquinolone pharmacodynamics, logarithmic-phase cultures (5 x 10(7) CFU/ml) were exposed to gatifloxacin at constant peak/MIC ratios of 2:1 to 3:1 at 0 and 24 h, elimination half-lives were varied to provide a range of AUC/MIC ratios, and changes in viable counts were measured over 30 h . As a comparison, levofloxacin was evaluated at similar peak/MIC ratios and at AUC/MIC ratios of 30 to 38 . For each strain, killing rates through 4 to 8 h were similar since peak/MIC ratios were kept constant . However, continued killing and eradication were observed only when gatifloxacin AUC/MIC ratios were 27 to 48 . Levofloxacin also provided eradication . In contrast, substantial regrowth was observed in most experiments when gatifloxacin AUC/MIC ratios were 9 to 24 . These data provide further support that fluoroquinolone AUC/MIC ratios of approximately 30 or higher can be sufficient for eradication of pneumococci from IVPMs . Furthermore, the overall impact of the AUC/MIC ratio was not influenced by the strain evaluated or its susceptibility to gatifloxacin . Further studies with other fluoroquinolones and pneumococci that exhibit wider ranges of susceptibilities are warranted . In addition, similar studies with higher peak/MIC ratios are needed to better define the impact of AUC/MIC ratios and peak/MIC ratios on the antipneumococcal pharmacodynamics of fluoroquinolones. J Soc Gynecol Investig, 2001 Nov-Dec, 8(6), 334 - 40 Production of pro- and anti-inflammatory cytokines of human placental trophoblasts in response to pathogenic bacteria; Griesinger G et al.; OBJECTIVE: We studied the production of cytokines in purified cultures of human term trophoblasts in the presence of pathogenic strains of Escherichia coli, Bacteroides fragilis, Mycoplasma hominis, Staphylococcus aureus, and Streptococcus agalactiae, which have been identified in intrauterine infections . METHODS: Human villous trophoblasts were isolated from term placentas after cesarean section and purified by several steps . After 6, 12, and 24 hours of incubation with the different heat-inactivated bacteria, interleukin-1beta (IL-1beta), interleukin-6 (IL-6), interleukin-8 (IL-8), and interleukin-10 (IL-10) as well as tumor necrosis factor-alpha (TNF-alpha) were measured from supernatants by commercially available enzyme-linked immunosorbent assay . Expression of cytokine mRNAs was determined by semiquantitative reverse transcriptase polymerase chain reaction (RT-PCR) . RESULTS: In nonstimulated cultures, low (IL-1beta and TNF-alpha) and high (IL-6, IL-8, and IL-10) basal secretion of cytokines was detectable . The pathogenic microorganisms induced a dose- and time-dependent release of IL-1beta, IL-6, IL-8, and IL-10, whereas TNF-alpha secretion was not elevated . E coli was the most potent inducer followed by B fragilis, S agalactiae, S aureus, and M hominis . Transcripts encoding IL-1beta, IL-6, IL-8, or IL-10 were elevated in the RT-PCR reactions, suggesting that transcriptional mechanisms contribute to elevated cytokine expression . CONCLUSION: Pathogenic microorganisms stimulated mRNA expression and polypeptide release of pro- and anti-inflammatory cytokines from placental trophoblasts . Induction of both inflammation-promoting and inflammation-inhibiting cytokines by bacterial products could play a role in modulating the inflammatory response associated with chorioamnionitis. FEMS Microbiol Lett, 2001 Dec 18, 205(2), 337 - 42 Characterization of two operons that encode components of fructose-specific enzyme II of the sugar:phosphotransferase system of Streptococcus mutans; Wen ZT et al.; Three genes, designated as fruC, fruD and fruI, were predicted to encode polypeptides homologous to fructose-specific enzyme II (II(Fru)) of the phosphoenolpyruvate-dependent sugar:phosphotransferase system, and were cloned from Streptococcus mutans, the primary etiological agent of human dental caries . The fruC and fruD genes encoded domains BC and domain A of II(Fru), respectively . The fruI gene encoded IICBA(Fru) . Northern hybridization and slot blot analysis showed that expression of fruI was inducible by sucrose and fructose, while fruCD were expressed constitutively and at much lower levels . Inactivation of either fruI or fruCD alone, or of both fruCD and fruI, had no major impact on growth on fructose at a concentration of 0.5% (w/v) . However, when the strains were grown with 0.2% fructose as the sole carbohydrate source, a significant decrease in the growth rate was seen with the fruCD/fruI double mutants . Assays of sugar:phosphotransferase activity showed that the fruCD/fruI double mutants had roughly 30% of the capacity of the wild-type strain to transport fructose via the phosphoenolpyruvate-dependent sugar:phosphotransferase system . Xylitol toxicity assays indicated that the inducible fructose permease was responsible for xylitol transport. Toxicol Appl Pharmacol, 2001 Dec 15, 177(3), 208 - 18 Correlation of suppressed natural killer cell activity with altered host resistance models in B6C3F1 mice; Wilson SD et al.; A number of methods have been developed to assess the impact of a xenobiotic on the various components of the immune system . For risk analysis, it is necessary to determine what degree of chemically induced immune perturbation translates into altered host resistance . Natural killer (NK) cells play a pivotal role in the innate immune system with the ability to lyse cells infected with intracellular pathogens and certain tumors without previous exposure to the antigen . Spontaneous NK activity in B6C3F1 mice could be incrementally and consistently decreased by 20 to > or =80% by the intravenous administration of a range of dilutions of anti-asialo GM1 (AAGM1) antibody . The decrease in spontaneous NK activity following a single iv administration of AAGM1 antibody persisted for up to approximately 3 weeks when the initial suppression (e.g., 24 h after AAGM1 antibody injection) was almost 100% . Treatment with AAGM1, however, did not appear to perturb the function of other immune cells, based on results of the plaque assay, the mixed lymphocyte response, the cytotoxic T lymphocyte assay, the reticuloendothelial system clearance of sRBC assay, and the Streptococcus pneumoniae host resistance assay . Following a > or =80% decrease in spontaneous NK activity in mice, challenge with > or =1 x 10(3) B16F10 melanoma cells resulted in an increase in tumor burden based on the number of lung nodules . However, following challenge with 1 x 10(5) melanoma cells, a significant increase in tumor burden in mice was not observed until spontaneous NK activity had been decreased by > or =50-60% . Altered host resistance is a function not only of the magnitude of the decrease in NK activity but also of the magnitude of the challenge to the host . (c)2001 Elsevier Science. Exp Parasitol, 2001 Oct, 99(2), 57 - 65 Plasmodium falciparum cytoadherence to human placenta: evaluation of hyaluronic acid and chondroitin 4-sulfate for binding of infected erythrocytes; Valiyaveettil M et al.; Chondroitin 4-sulfate (C4S) is known to mediate the adherence of Plasmodium falciparum infected red blood cells (IRBCs) to human placenta . Recently, hyaluronic acid (HA) has also been reported to bind IRBCs, and HA has been suggested as an additional receptor for the sequestration of IRBCs in the placenta . In this study, we assessed the adherence of 3D7 parasite strain, which has been reported to bind both C4S and HA, using highly purified clinical grade rooster comb HA, Streptococcus HA, several preparations of human umbilical cord HA (hucHA), and bovine vitreous humor HA (bvhHA) . While all hucHA preparations and bvhHA bound with moderate to high density to IRBCs, the rooster comb and bacterial HAs did not bind IRBCs . IRBCs binding to the hucHA and bvhHA could be abolished by pretreatment with testicular hyaluronidase but not with Streptomyces hyalurolyticus hyaluronidase, suggesting that IRBC binding to hucHA and bvhHA was due to chondroitin sulfate (CS) contaminants in HAs . Compositional analysis confirmed the presence of CS in both hucHA and bvhHA . The CSs present in these commercial hucHA and bvhHA samples were isolated, characterized, and studied for their ability to bind IRBCs . The data suggested that IRBC adherence to hucHA and bvhHA was mediated by the CS present in these samples . However, our data did not exclude the possibility of a minor population of distinct parasite subtype adhering to HA and further studies using pure HA conjugated to proteins or lipids and placental parasite isolates should clarify whether HA is an in vivo receptor for IRBC adherence . Arch Ophthalmol, 2001 Dec, 119(12), 1755 - 9 Clear corneal wound infection after phacoemulsification; Cosar CB et al.; OBJECTIVE: To evaluate clear corneal wound infections after phacoemulsification . MATERIALS AND METHODS: The medical records of 7 patients with clear corneal wound infections after phacoemulsification were reviewed retrospectively . Data that were reviewed included patient age, sex, onset of symptoms and signs after surgery, possible risk factors for infection, concomitant ocular disease, use of perioperative prophylactic antibiotics and steroids, culture and antibiotic sensitivity results, treatment regimen, and outcome . RESULTS: The median onset of signs and symptoms after surgery was 10 days (range, 4-60 days) . Corneal cultures yielded methicillin-resistant Staphylococcus aureus in 2 cases, Streptococcus pneumoniae in 1 case, and Staphylococcus epidermidis in 1 case . Cultures yielded no microorganisms for 1 patient . Corneal cultures were not obtained in 2 patients . In 3 of the 4 culture-positive cases, the isolated microorganisms were resistant to the perioperative prophylactic antibiotics (fluoroquinolones and tobramycin) that were used . No possible risk factors were noted except use of topical steroids 4 times a day without antibiotic coverage for iritis before referral in one of our patients . Six of these 7 wound infections healed with topical antibiotic therapy . One of the patients required lamellar keratectomy and conjunctival flap for complete healing . In 4 of the 7 cases, best-corrected visual acuity at the last follow-up visit was better than 20/40 . CONCLUSIONS: Clear corneal wound infection after phacoemulsification is a serious complication of cataract surgery . Infections are caused by gram-positive organisms sensitive to bacitracin and the combination of trimethoprim-sulfamethoxazole but often resistant to aminoglycosides and/or fluoroquinolones. J Antimicrob Chemother, 2001 Dec, 48(6), 915 - 8 Evaluation of PCR primers to screen for Streptococcus pneumoniae isolates and beta-lactam resistance, and to detect common macrolide resistance determinants; Nagai K et al.; Pneumococcal isolates (n = 148) from various countries (mostly from the USA) were tested by a primer set for PCR . Thirty-eight (86.4%) of the 44 penicillin G-susceptible isolates (MIC < or = 0.06 mg/L) had unaltered pbps, while six isolates (13.6%) had either one or two alterations in pbps . Of 47 penicillin G-resistant strains (MIC > or = 2 mg/L), 41 isolates (87.2%) had all three pbps altered, six isolates (12.8%) had altered pbp1a + 2x . Various combinations of altered pbp were seen in penicillin G-intermediate isolates . Prevalence of macrolide resistance genes mef(A) and erm(B) in isolates was clearly reflected by their MICs . All isolates were positive for lytA . The primers were useful for screening for Streptococcus pneumoniae and beta-lactam resistance, and for detection of common macrolide resistance determinants. J Antimicrob Chemother, 2001 Dec, 48(6), 821 - 6 The pharmacodynamics of gatifloxacin and ciprofloxacin for pneumococci in an in vitro dynamic model: prediction of equiefficient doses; Zinner SH et al.; Enhanced activity against Streptococcus pneumoniae is one of the putative advantages of gatifloxacin over older fluoroquinolones such as ciprofloxacin . This study examined ciprofloxacin and gatifloxacin pharmacodynamics against two differentially susceptible clinical isolates of S . pneumoniae (gatifloxacin MIC, 0.125 and 2 mg/L; ciprofloxacin MIC, 1 and 32 mg/L) . The pharmacokinetics of gatifloxacin (single dose) and ciprofloxacin (two 12 hourly doses) with half-lives of 6 and 5 h, respectively, were simulated using a two-compartment dynamic model . The AUC/MIC ratios in the peripheral compartments that contain bacterial cultures varied over a four- to five-fold range, from 11 to 48 h with ciprofloxacin and from 15 to 78 h with gatifloxacin . The intensity of the antimicrobial effect (IE) increased with increasing AUC/MIC ratios in a strain-independent fashion, although different relationships of IE to log AUC/MIC were inherent for each drug (r2 0.73 for gatifloxacin and r2 0.94 for ciprofloxacin) . Subsequently, the respective dose-response relationships of gatifloxacin and ciprofloxacin for a hypothetical strain of S . pneumoniae with MIC equal to the MIC50 were modelled . Based on these relationships, the equiefficient doses of gatifloxacin and ciprofloxacin were predicted for MIC50S of 0.4 and 1 mg/L, respectively . Gatifloxacin 400 mg was predicted to be equiefficient to ciprofloxacin 1400 mg . To provide the same anti-pneumococcal effect as the usual 1000 mg daily dose of ciprofloxacin, the respective daily dose of gatifloxacin could be as low as 180 mg . This in vitro study demonstrates advantages of gatifloxacin relative to ciprofloxacin in terms of the dose-dependent total antimicrobial effect. Arch Intern Med, 2001 Nov 26, 161(21), 2538 - 44 A fresh look at the definition of susceptibility of Streptococcus pneumoniae to beta-lactam antibiotics; Musher DM et al.; Definitions for susceptibility or resistance of Streptococcus pneumoniae to penicillin were not developed until penicillin-resistant pneumococci appeared in South Africa in the late 1970s . The definition that was accepted (which still remains in use) and later definitions of resistance to most other beta-lactam antibiotics were derived from laboratory and clinical data relating to the treatment of meningitis, not otitis media, sinusitis, or pneumonia . An understanding of the origin of these definitions helps to resolve the apparent paradox that infections of the respiratory tract due to seemingly beta-lactam-resistant pneumococci may still respond well to standard doses of these drugs . A recently sanctioned change in the definition of susceptibility to amoxicillin is helpful in eliminating the paradox for this drug, but it may create further confusion by implying that, on a microgram basis, amoxicillin is substantially more effective than penicillin or third-generation cephalosporins . This article examines definitions of susceptibility and resistance of pneumococci, highlighting areas that have led to confusion and proposing a new way of understanding them. J Lab Clin Med, 2001 Nov, 138(5), 338 - 42 Bacterial pathogens of otitis media and sinusitis: detection in the nasopharynx with selective agar media; Dudley S et al.; Carriage rates for the bacterial pathogens associated with otitis media (Streptococcus pneumoniae {SP}, Hemophilus influenzae {HI}, and Moraxella catarrhalis {MC}) are of interest . Culture on three selective agars was compared with culture on two standard agars to determine the more accurate method for detection of these species in the nasopharynx of healthy children . Weekly samples were obtained in winter from 18 healthy children (ages 1 through 9 years) as part of a longitudinal study . A 0.1-mL sample of 116 nasopharyngeal aspirate/washes was inoculated onto each of five agars . Two were standard (sheep blood and chocolate), and three were selective (blood with gentamicin for SP; chocolate with vancomycin, bacitracin, and clindamycin for HI; blood with amphotericin B, vancomycin, trimethoprim, and acetazolamide for MC) . One technician read the standard plates and another the selective; both were blinded to the results of the other . SP was found in 44% of samples with selective agar versus 25% with standard agar; HI was found in 31% with selective versus 9% with standard; MC was found in 56% with selective versus 37% with standard . Overall, 80% of samples had one or more pathogens detected with selective agars as compared with 58% with standard agars (P =.0004) . Selective agars were more accurate than standard agars for detecting otitis pathogens in the nasopharynx, where they are a common part of normal flora in healthy children. Infect Immun, 2002 Jan, 70(1), 412 - 5 Contribution of choline-binding proteins to cell surface properties of Streptococcus pneumoniae; Swiatlo E et al.; Nonspecific interactions related to physicochemical properties of bacterial cell surfaces, such as hydrophobicity and electrostatic charge, are known to have important roles in bacterium-host cell encounters . Streptococcus pneumoniae (pneumococcus) expresses multiple, surface-exposed, choline-binding proteins (CBPs) which have been associated with adhesion and virulence . The purpose of this study was to determine the contribution of CBPs to the surface characteristics of pneumococci and, consequently, to learn how CBPs may affect nonspecific interactions with host cells . Pneumococcal strains lacking CBPs were derived by adapting bacteria to a defined medium that substituted ethanolamine for choline . Such strains do not anchor CBPs to their surface . Cell surface hydrophobicity was tested for the wild-type and adapted strains by using a biphasic hydrocarbon adherence assay, and electrostatic charge was determined by zeta potential measurement . Adherence of pneumococci to human-derived cells was assessed by fluorescence-activated cell sorter analysis . Strains lacking both capsule and CBPs were significantly more hydrophobic than nonencapsulated strains with a normal complement of CBPs . The effect of CBPs on hydrophobicity was attenuated in the presence of capsule . Removal of CBPs conferred a greater electronegative net surface charge than that which cells with CBPs possessed, regardless of the presence of capsule . Strains that lack CBPs were poorly adherent to human monocyte-like cells when compared with wild-type bacteria with a full complement of CBPs . These results suggest that CBPs contribute significantly to the hydrophobic and electrostatic surface characteristics of pneumococci and may facilitate adherence to host cells partially through nonspecific, physicochemical interactions. Infect Immun, 2002 Jan, 70(1), 249 - 56 Functional variation of the antigen I/II surface protein in Streptococcus mutans and Streptococcus intermedius; Petersen FC et al.; Although Streptococcus intermedius and Streptococcus mutans are regarded as members of the commensal microflora of the body, S . intermedius is often associated with deep-seated purulent infections, whereas S . mutans is frequently associated with dental caries . In this study, we investigated the roles of the S . mutans and S . intermedius antigen I/II proteins in adhesion and modulation of cell surface characteristics . By using isogenic mutants, we show that the antigen I/II in S . mutans, but not in S . intermedius, was involved in adhesion to a salivary film under flowing conditions, as well as in binding to rat collagen type I . Binding to human fibronectin was a common function associated with the S . mutans and S . intermedius antigen I/II . Adhesion of S . mutans or S . intermedius to human collagen types I or IV was negligible . Hydrophobicity, as measured by water contact angles, and zeta potentials were unaltered in the S . intermedius mutant . The S . mutans isogenic mutants, on the other hand, exhibited more positive zeta potentials at physiological pH values than did the wild type . The results indicate common and species-specific roles for the antigen I/II in mediating the attachment of S . mutans and S . intermedius to host components and in determining cell surface properties. Infect Immun, 2002 Jan, 70(1), 134 - 9 Long-range mapping of the Streptococcus agalactiae phylogenetic lineage restriction digest pattern type III-3 reveals clustering of virulence genes; Bohnsack JF et al.; Human isolates of serotype III Streptococcus agalactiae (group B streptococcus {GBS}) can be divided into three separate phylogenetic lineages based on analysis of the restriction digest patterns (RDPs) of chromosomal DNA . Nine DNA sequences that are present in all isolates of the RDP III-3 phylogenetic lineage, but not in the other lineages, were identified by genomic subtractive hybridization . A complete physical map of a III-3 chromosome was constructed . Six of the nine III-3-specific sequences mapped to a 340-kb Sse8387I fragment which contains or is located close to known GBS virulence genes . One of the III-3-specific probes, AW-10, encodes part of GBSi1, a group II intron that is inserted at two sites within the GBS genome . The second chromosomal site for GBSi1 was isolated, sequenced, and mapped to a location near the locus responsible for hemolysin production . These findings suggest that the genetic variation that distinguishes the RDP type III-3 strains from other serotype III strains occurs largely within localized areas of the genome containing known or putative virulence genes. Infect Immun, 2002 Jan, 70(1), 107 - 13 Induction of gamma interferon and nitric oxide by truncated pneumolysin that lacks pore-forming activity; Baba H et al.; Pneumolysin (PLY), an important virulence factor of Streptococcus pneumoniae, is known to exert various effects on the host immune cells, including cytokine induction, in addition to its known cytolytic activity as a member of the thiol-activated cytolysins . It is of interest to determine whether cytolytic activity is involved in triggering the cytokine production . In this study, we constructed full-length recombinant PLY and noncytolytic truncated PLYs with C-terminal deletions to examine the response of spleen cells to these PLY preparations . When cytolytic activity was blocked by treatment with cholesterol, full-length PLY was capable of inducing gamma interferon (IFN-gamma) production . Truncated PLYs that originally exhibited no cytolytic activity were also active in IFN-gamma induction . Therefore, the IFN-gamma-inducing ability of PLY appeared to be independent of the cytolytic activity . Furthermore, IFN-gamma-inducing preparations were also capable of inducing nitric oxide synthase expression and nitric oxide (NO) production, and the addition of neutralizing antibody to IFN-gamma abolished the NO production . These results clearly demonstrated that PLY is capable of inducing IFN-gamma production in spleen cells by a mechanism different from pore formation and that the induced IFN-gamma stimulates NO production . These findings were discussed with reference to the contribution of PLY to the virulence of S . pneumoniae in vivo. Lancet, 2001 Dec 8, 358(9297), 1975 - 82 Oxazolidinone antibiotics; Diekema DJ et al.; Many common gram-positive pathogens (eg, Staphylococcus aureus, Enterococcus spp, and Streptococcus pneumoniae) have become increasingly resistant to antimicrobial agents, and new drugs with activity against gram-positive bacteria are urgently needed . The oxazolidinones, a new chemical class of synthetic antimicrobial agent, have a unique mechanism of inhibiting bacterial protein synthesis . Linezolid, the first oxazolidinone to be approved for clinical use, displays in-vitro activity (generally bacteriostatic) against many important resistant pathogens, including meticillin-resistant Staph aureus, vancomycin-resistant enterococci, and penicillin-resistant Strep pneumoniae . Linezolid is a parenteral agent that also possesses near-complete oral bioavailability plus favourable pharmacokinetic and toxic effect profiles . Clinical trials confirm the activity of linezolid in the setting of pneumonia, skin and soft-tissue infections, and infections due to vancomycin-resistant enterococci . Linezolid shows promise as an alternative to glycopeptides and streptogramins to treat serious infections due to resistant gram-positive organisms . New agents with greater potency and new spectra of activity could arise from further modification of the oxazolidinone nucleus. Emerg Infect Dis, 2001 Sep-Oct, 7(5), 906 - 8 Fluoroquinolone resistance among Streptococcus pneumoniae in Hong Kong linked to the Spanish 23F clone; Ho PL et al.; Serotypes 6A/B, 19F, and 23F accounted for 73% of 140 mucosal isolates of Streptococcus pneumoniae from Hong Kong . In pulsed-field gel electrophoresis analysis, a group of related patterns was shared by 14 of 15 ciprofloxacin-resistant and 12 of 16 ciprofloxacin-susceptible isolates . These strains exhibited capsular switching and were highly similar to the Spanish 23F clone. Emerg Infect Dis, 2001 Sep-Oct, 7(5), 832 - 6 Pneumococcal surface protein A of invasive Streptococcus pneumoniae isolates from Colombian children; Vela Coral MC et al.; Pneumococcal surface protein A (PspA) elicits protection in mice against fatal bacteremia and sepsis caused by genetically diverse pneumococci and protects against carriage and lung infection . We determined the PspA families of invasive isolates of Streptococcus pneumoniae recovered from Colombian children <5 years of age . That 97.5% of Colombian isolates belong to PspA families 1 and 2 supports the hypothesis that a human PspA vaccine covering a few PspA families could be broadly effective. DNA Cell Biol, 2001 Sep, 20(9), 595 - 601 Expression of Streptococcus mutans wall-associated protein A gene in Chinese hamster ovary cells: prospect for a dental caries DNA vaccine; Han TK et al.; The Streptococcus mutans strain GS-5 wall-associated protein A (Wap-A) is a precursor to the extracellular antigen A (AgA), a recognized candidate dental caries vaccine . The full-length wapA gene (wapA-E) and a C-terminal truncated version (wapA-G) encoding the AgA were cloned into the mammalian expression vector pcDNA 3.1/V5/His-TOPO . The resulting constructs were propagated in the Escherichia coli Top10 . To investigate the expression of the S . mutans genes in mammalian cells, the above constructs were used to transfect Chinese hamster ovary (CHO) cells in the presence of the cationic lipid pfx-8 . Transient expression of the wapA-E and wapA-G genes was observed at 24 h post-transfection, as shown by Western immunoblot analysis using a rabbit antiserum to S . mutans cell wall . Immunochemical staining of the transfected CHO cells showed expression of WapA mainly in the cells and budding vesicles, whereas AgA was found mainly in the transfected cells and extracellular medium . The expression of S . mutans proteins in CHO cells, in either vesicles or soluble form, suggested an antibody response to the above DNA constructs . Work is under way to test the efficacy of these as DNA vaccines against S . mutans. Biochemistry, 2001 Dec 25, 40(51), 15811 - 23 Kinetic and mechanistic studies of penicillin-binding protein 2x from Streptococcus pneumoniae; Thomas B et al.; High molecular weight penicillin-binding proteins (PBPs) are bifunctional enzymes that build bacterial cell walls from the glycopeptide lipid II {GlcNAc-MurNAc(L-Ala-gamma-D-Glu-L-Lys-D-Ala-D-Ala)-pyrophosphate-undecaprenol} by a process involving disaccharide polymerization and peptide cross-linking . The latter reaction involves acyl-transfer chemistry in which the penultimate (D)Ala first acylates the active-site serine, with release of the terminal (D)Ala, and is then transferred to the epsilon-amine of a Lys on a neighboring pentapeptide chain . These enzymes also catalyze hydrolysis of specific thioester substrates and acylation by beta-lactam antibiotics . In this paper, we explore these latter two reactions and report mechanistic experiments on the reaction of Streptococcus pneumoniae PBP 2x with N-benzoyl-(D)Ala-thioacetic acid {Bz-(D)Ala-(S)Gly} and penicillin G . For these experiments, we used PBP 2x, a soluble form of PBP 2x in which the transmembrane domain was deleted . The following results are significant: (1) pH dependencies for acylation of PBP 2x by penicillin G and Bz-(D)Ala-(S)Gly are identical, suggesting that the same ionizable residues are involved in both reactions and that these residues play the same catalytic role in the two processes . On the basis of these results, we propose a mechanistic model that is also consistent with recently published structural data {Gordon, E., et al . (2000) J . Mol . Biol . 299, 477-485} . (2) Pre-steady-state experiments for the PBP 2x-catalyzed hydrolysis of Bz-(D)Ala-(S)Gly at pH 6.5 indicate that k(c) is principally rate-limited by acylation with some contribution from deacylation . The contribution of these steps to rate limitation is pH-dependent, with acylation entirely rate-limiting at pH values less than 5.5 and deacylation principally rate-limiting above pH 8.5 . (3) Results of solvent isotope effect and proton inventory experiments for acylation suggest a complex process that is at least partially rate-limited by chemistry with some involvement of changes in solvation and/or enzyme conformation . (4) Analysis of activation parameters suggests that during the acylation of PBP 2x by penicillin G the inherent chemical stability of penicillin's amide bond, as manifested in the enthalpy of activation, is offset by a favorable entropy term that reflects penicillin's rotationally constrained bicyclic system, which presumably allows a less energetically demanding entry into the transition state for acylation. Microb Pathog, 2001 Dec, 31(6), 309 - 17 Comparison of structural changes of cell surface carbohydrates in the eustachian tube epithelium of chinchillas infected with a Streptococcus pneumoniae neuraminidase-deficient mutant or its isogenic parent strain; Tong HH et al.; Six different lectin probes were used to examine alterations of the cell surface carbohydrates in the chinchilla eustachian tube (ET) lumen subsequent to the intranasal (i.n.) challenge with the Streptococcus pneumoniae parent strain, D39, or its isogenic derivative, DeltaNA1, which is deficient in neuraminidase NanA . The labelling pattern revealed that the binding of wheat germ agglutinin (WGA), Erythrina cristagalli lectin (ECL), peanut agglutinin (PNA), Bandeiraea simplicifolia lectin II (BSL II) and succinylated wheat germ agglutinin (SWGA) were increased in the lumenal surface of the ET in the D39 inoculated cohort compared to the uninfected control, which indicated that N-acetylglucosamine (GlcNAc) and D-galactose residues were exposed . Concurrently, decreased labelling with Sambucus nigra agglutinin (SNA) indicated that there were few sialic acid residues remaining in the ET epithelium subsequent to i.n . inoculation with D39 . The DeltaNA1 neuraminidase deficient mutant, however, did not induce any significant changes in the lectin labelling patterns, and was comparable to that of the control cohort . We propose that products of the nanA gene have a significant impact on the changes of the carbohydrate moieties in the ET epithelium and may be responsible for the previously reported increased ability of the D39 parent to colonize the nasopharynx and invade the middle ear . J Pharm Sci, 2001 Dec, 90(12), 2088 - 98 Microdialysis studies of the middle ear distribution kinetics of amoxicillin in the awake chinchilla; Huang Y et al.; This work was performed to develop an experimental animal model for the study of antibiotic drug distribution into middle ear fluid (MEF) and to evaluate its relevance and significance to the clinical treatment of otitis media (OM) . Chinchillas were assigned to normal or infected ear groups after Eustachian tube obstruction (ETO) or direct trans-bullar inoculation with type 3 Streptococcus pneumoniae . Following survival surgery to implant microdialysis (MD) probes in the jugular vein and middle ear (ME), amoxicillin was given intravenously (iv) as a bolus or infusion . Drug concentrations in blood and MEF were continuously monitored by microdialysis . The measured concentrations were corrected for probe recovery by simultaneous retrodialysis . Multiple MEF and blood sampling was also performed to validate the animal model and MD sampling technique . Bacterial infection was successfully induced 3-7 days after the inoculation, whereas the control group gave negative bacterial culture results . The beta-lactam antibiotic, amoxicillin, exhibited an elimination half-life of 0.33+/-0.23 h (n = 9) in chinchilla blood, 1.46+/-0.50 h (n = 5) and 1.75+/-0.84 h (n = 4) in MEF of normal and infected ears (p = 0.6), respectively . MEF-to-blood amoxicillin concentration ratios at steady state following iv infusion were 0.26+/-0.06 (n = 5) and 0.28+/-0.11 (n = 4) for normal and infected ears (p = 0.7), respectively . MD allows continuous monitoring of drug concentration-time profiles in blood and MEF in an awake chinchilla model . The concentrations measured by MD were validated by direct sampling . The ratio of the area under the curve (AUC) of drug concentration in MEF versus time to that in blood after iv bolus doses was less than unity, as was the steady-state concentration ratio following constant-rate iv infusion, suggesting an active transport mechanism was involved in the efflux of amoxicillin from the ME of chinchilla . The results of studies involving infected ears were not significantly different from those in normal ears in terms of amoxicillin distribution across the ME mucosal membrane after systemic administration . Biotechnol Bioeng, 2001 Dec, 76(4), 395 - 9 Electric field induced desorption of bacteria from a conditioning film covered substratum; Poortinga AT et al.; Desorption of three oral bacterial strains from a salivary conditioning film on an indium tin oxide electrode during application of a positive (bacterial adhesion to the anode) or a negative electric current was studied in a parallel plate flow chamber . Bacterial adhesion was from a flowing suspension of high ionic strength, after which the bacterial suspension was replaced by a low ionic strength solution without bacteria and currents ranging from -800 to +800 microA were applied . Streptococcus oralis J22 desorbed during application of a positive and negative electric current with a desorption probability that increased with increasing electric current . Two actinomyces strains, however, could not be stimulated to desorb by the electric currents applied . The desorption forces acting on adhering bacteria are electroosmotic in origin and working parallel to the electrode surface in case of a positive current, whereas they are electrophoretic and electrostatic in origin and working perpendicular to the surface in case of a negative current . By comparison of the effect of positive and negative electric currents, it can be concluded that parallel forces are more effective in stimulating bacterial desorption than perpendicular forces . The results of this study point to a new pathway of cleaning industrial and biomedical surfaces without the use of detergents or biocides . Anim Reprod Sci, 2001 Dec 3, 68(3-4), 229 - 37 The role of international transport of equine semen on disease transmission; Metcalf ES; Despite the numerous benefits of having the capability to transport semen internationally, there are serious potential ramifications if that semen is contaminated with a communicable disease . BACTERIA: Many commensal bacteria colonize the exterior of the stallion penis and are not regarded as pathogenic . They may be cultured from an ejaculate . Alterations of the normal bacterial flora on the exterior genitalia may cause the growth of opportunistic bacteria such as Klebsiella pneumonia, Pseudomonas aeruginosa, Streptococcus zooepidemicus, which, if inseminated, may cause infertility in susceptible mares . Contagious equine metritis (CEM), a highly transmissible, true venereal disease of horses, is caused by the gram-negative coccobacillis, Taylorella equigenitalis . Even with the use of rigorous testing protocols, the current techniques used may not ensure accuracy of results . VIRUSES: Equine coital exanthema (equine herpes virus type 3; EHV-3) is a highly contagious virus that causes painful lesions on the stallion's penis and mare's vulva . Although it is primarily transmitted through coitus, infected fomites have also been implicated in its spread . Therefore, it is possible that the virus can potentially be transmitted to the ejaculate through penile contact with an artificial vagina or sleeve . Equine arteritis virus appears to be becoming more prevalent in recent years . The most common method of transmission is through respiratory disease, but the organism can also be shed in the semen of asymptomatic stallions . Equine infectious anemia virus has also been found to be present in the semen of an infected stallion, although no evidence exists at this time that there is venereal transmission of this disease . PROTOZOA: Dourine, caused by Trympanosoma equiperidum, is a venereal disease found only in Africa, South and Central America and the Middle East . Serological testing using complement fixation is recommended for diagnosis . Piroplasmosis, a disease caused by Babesia equi or by a less severe strain, Babesia caballi, has received a great deal of attention in recent years due to the increased transfer of horses between countries . It is considered to be enzootic in many areas of the southern US, and is found throughout the world . The protozoal agent is most often spread by ticks, but mechanical transmission has also been documented; therefore, there is concern for venereal transmission if blood from an infected horse contaminates the semen. J Bacteriol, 2002 Jan, 184(1), 126 - 33 Analysis of cis- and trans-acting factors involved in regulation of the Streptococcus mutans fructanase gene (fruA); Wen ZT et al.; There are two primary levels of control of the expression of the fructanase gene (fruA) of Streptococcus mutans: induction by levan, inulin, or sucrose and repression in the presence of glucose and other readily metabolized sugars . The goals of this study were to assess the functionality of putative cis-acting regulatory elements and to begin to identify the trans-acting factors involved in induction and catabolite repression of fruA . The fruA promoter and its derivatives generated by deletions and/or site-directed mutagenesis were fused to a promoterless chloramphenicol acetyltransferase (CAT) gene as a reporter, and strains carrying the transcriptional fusions were then analyzed for CAT activities in response to growth on various carbon sources . A dyadic sequence, ATGACA(TC)TGTCAT, located at -72 to -59 relative to the transcription initiation site was shown to be essential for expression of fruA . Inactivation of the genes that encode fructose-specific enzymes II resulted in elevated expression from the fruA promoter, suggesting negative regulation of fruA expression by the fructose phosphotransferase system . Mutagenesis of a terminator-like structure located in the 165-base 5' untranslated region of the fruA mRNA or insertional inactivation of antiterminator genes revealed that antitermination was not a mechanism controlling induction or repression of fruA, although the untranslated leader mRNA may play a role in optimal expression of fructanase . Deletion or mutation of a consensus catabolite response element alleviated glucose repression of fruA, but interestingly, inactivation of the ccpA gene had no discernible effect on catabolite repression of fruA . Accumulating data suggest that expression of fruA is regulated by a mechanism that has several unique features that distinguish it from archetypical polysaccharide catabolic operons of other gram-positive bacteria. J Bacteriol, 2002 Jan, 184(1), 119 - 25 Characterization of PauB, a novel broad-spectrum plasminogen activator from Streptococcus uberis; Ward PN et al.; A bovine plasminogen activator of atypical molecular mass ( approximately 45 kDa) from Streptococcus uberis strain SK880 had been identified previously (L . B . Johnsen, K . Poulsen, M . Kilian, and T . E . Petersen . Infect . Immun . 67:1072-1078, 1999) . The strain was isolated from a clinical case of bovine mastitis . The isolate was found not to secrete PauA, a bovine plasminogen activator expressed by the majority of S . uberis strains . Analysis of the locus normally occupied by pauA revealed an absence of the pauA open reading frame . However, an alternative open reading frame was identified within the same locus . Sequence analysis of the putative gene suggested limited but significant homology to other plasminogen activators . A candidate signal peptide sequence and cleavage site were also identified . Expression cloning of DNA encoding the predicted mature protein (lacking signal peptide) confirmed that the open reading frame encoded a plasminogen activator of the expected size, which we have named PauB . Both native and recombinant forms of PauB displayed an unexpectedly broad specificity profile for bovine, ovine, equine, caprine, porcine, rabbit, and human plasminogen . Clinical and nonclinical field isolates from nine United Kingdom sites were screened for the pauB gene and none were identified as carrying it . Similarly, clinical isolates from 20 Danish herds were all found to encode PauA and not PauB . Therefore, PauB represents a novel but rare bacterial plasminogen activator which displays very broad specificity. J Dent, 2002 Jan, 30(1), 37 - 40 An update on infective endocarditis of dental origin; Tomas Carmona I et al.; OBJECTIVES: The aim of this study was to analyse the prevalence of dental treatment and oral infections related to the development of infective endocarditis (IE) . METHODS: A retrospective study of 103 cases of IE diagnosed from 1997 to 1999 was conducted in Galicia, Spain . RESULTS: According to the Duke's endocarditis criteria (1994), 87 cases (84.5%) were considered definite IE . A presumed oral portal of entry was recorded in 12 patients (13.7%) . Oral infections were held responsible in six cases while the remaining six had received dental treatment in the previous three months (three tooth extractions, one scaling, one cleaning, one fillings) . In eight cases of IE (66.6%) typical oral pathogenic microflora was identified, with Streptococcus viridans being the most frequent . In four patients no previous cardiac disease was recorded . CONCLUSIONS: These results suggest that prevalence and characteristics of IE cases of dental origin did not change significantly in the last decades . The need for increased oral hygiene and improved dental care should be emphasized on preventing IE of dental origin . Continued education of physicians and dentists on the importance of the knowledge of current prophylactic protocols should also be considered. Clin Infect Dis, 2002 Jan 15, 34(2), 184 - 90 Epub 2001 Dec 05. Group B Streptococcus colonization in male and nonpregnant female university students: a cross-sectional prevalence study; Bliss SJ et al.; We describe the prevalence of colonization with group B Streptococcus species in a random sample of otherwise healthy male and nonpregnant female college students . Colonization with group B Streptococcus species occurs at a high frequency among healthy students, and there was a suggestion that it is associated with having engaged in sexual activity, tampon use, milk consumption, and hand washing done < or =4 times per day . However, larger studies are needed to verify these findings. Nature, 2001 Dec 6, 414(6864), 648 - 52 Group A Streptococcus tissue invasion by CD44-mediated cell signalling; Cywes C et al.; Streptococcus pyogenes (also known as group A Streptococcus, GAS), the agent of streptococcal sore throat and invasive soft-tissue infections, attaches to human pharyngeal or skin epithelial cells through specific recognition of its hyaluronic acid capsular polysaccharide by the hyaluronic-acid-binding protein CD44 (refs 1, 2) . Because ligation of CD44 by hyaluronic acid can induce epithelial cell movement on extracellular matrix, we investigated whether molecular mimicry by the GAS hyaluronic acid capsule might induce similar cellular responses . Here we show that CD44-dependent GAS binding to polarized monolayers of human keratinocytes induced marked cytoskeletal rearrangements manifested by membrane ruffling and disruption of intercellular junctions . Transduction of the signal induced by GAS binding to CD44 on the keratinocyte surface involved Rac1 and the cytoskeleton linker protein ezrin, as well as tyrosine phosphorylation of cellular proteins . Studies of bacterial translocation in two models of human skin indicated that cell signalling triggered by interaction of the GAS capsule with CD44 opened intercellular junctions and promoted tissue penetration by GAS through a paracellular route . These results support a model of host cytoskeleton manipulation and tissue invasion by an extracellular bacterial pathogen. Science, 2001 Dec 7, 294(5549), 2170 - 2 Rapid killing of Streptococcus pneumoniae with a bacteriophage cell wall hydrolase; Loeffler JM et al.; Nasopharyngeal carriage is the major reservoir for Streptococcus pneumoniae in the community . Although eliminating this reservoir would greatly reduce disease occurrence, no suitable intervention has been available for this purpose . We show here that seconds after contact, a purified pneumococcal bacteriophage lytic enzyme (Pal) is able to kill 15 common serotypes of pneumococci, including highly penicillin-resistant strains . In vivo, previously colonized mice revealed undetectable pneumococcal titers 5 hours after a single enzyme treatment . Pal enzyme had little or no effect on microorganisms normally found in the human oropharynx, and Pal-resistant pneumococci could not be detected after extensive exposure to the enzyme. Microbiology, 2001 Dec, 147(Pt 12), 3311 - 22 The fibrinogen-binding protein (FgBP) of Streptococcus equi subsp . equi additionally binds IgG and contributes to virulence in a mouse model; Meehan M et al.; The major cell-wall-associated protein of the equine pathogen Streptococcus equi subsp . equi is an M-like fibrinogen-binding protein (FgBP) which binds equine fibrinogen (Fg) avidly, through residues located at the extreme N-terminus of the molecule . In this study, it is shown that FgBP additionally binds equine IgG-Fc . When tested against polyclonal IgG from ten other animal species, it was found that FgBP binds human, rabbit, pig and cat IgG, but does not bind mouse, rat, goat, sheep, cow or chicken IgG . Through the use of a panel of recombinant FgBP truncates containing defined deletions of sequence, it was shown that residues in the central regions of FgBP are important in IgG binding . An fbp knockout mutant which does not express FgBP on the cell surface was also constructed . Mutant cells failed to autoaggregate, bound no detectable equine Fg or IgG-Fc, were rapidly killed in horse blood, and showed greatly decreased virulence in a mouse model . Results suggest that FgBP is the major surface structure responsible for binding either Fg or IgG, that the molecule has pronounced antiphagocytic properties, and that it is a likely factor contributing to the virulence of wild-type S . equi subsp . equi. Prim Care, 2001 Dec, 28(4), 791 - 806, vi-vii Maternal vaccines; Glezen WP; Acute lower respiratory illness (LRI) is the leading cause of disease worldwide as measured by disability-adjusted life years . New strategies are necessary to decrease the disease burden that is largely borne by infants . Respiratory syncytial virus is the most important cause of LRI in infants . Lower respiratory illness can be prevented by endowing infants with high levels of neutralizing antibodies from mothers whose antibodies are boosted during pregnancy with a potent subunit vaccine . Another important cause of infant mortality is group B streptococcus sepsis in the neonatal period; maternal immunization with a group B conjugate vaccine could prevent this devastating infection. Vaccine, 2001 Dec 12, 20(5-6), 805 - 12 PsaA (pneumococcal surface adhesin A) and PspA (pneumococcal surface protein A) DNA vaccines induce humoral and cellular immune responses against Streptococcus pneumoniae; Miyaji EN et al.; Streptococcus pneumoniae is one of the most important human pathogens and improvement of the currently used polysaccharide vaccines is being pursued . We constructed DNA vaccine vectors containing either the full-length psaA (pneumococcal surface adhesin A) or a truncated pspA (pneumococcal surface protein A--pspA') gene . Both constructs showed transient expression of the antigens in vertebrate cells and induced significant antibody response to the pneumococcal antigens in BALB/c mice injected intramuscularly (i.m.) . Fusion with an N-terminal cytoplasmatic SV40 T-antigen (CT-Ag), which was previously shown to stabilize poorly expressed antigens through association with Hsp73, also induced anti-PspA antibody response . The induction of antibodies with a low IgG1:IgG2a ratio and elevated gamma interferon (IFN-gamma) production by spleen cells elicited by DNA vaccination indicate preferential priming of Th1 immunity . Since induction of antibodies against both PsaA and PspA was previously shown to correlate with protection against fatal infection with S . pneumoniae and cell-mediated immune responses could contribute to protection, further evaluation of PsaA and PspA as antigens for a DNA vaccine against S . pneumoniae could be promising. Int J Antimicrob Agents, 2001 Dec, 18(6), 553 - 7 In vitro antimicrobial activity of a chitooligosaccharide mixture against Actinobacillus actinomycetemcomitans and Streptococcus mutans; Choi BK et al.; The purpose of this study was to evaluate the in vitro antibacterial activity of a chitooligosaccharide mixture (MW 2000-30000 Da) with a deacetylation degree of 91.5% against two representative oral pathogens, Actinobacillus actinomycetemcomitans and Streptococcus mutans . A 0.1% concentration of the chitooligosaccharides (derived from the exoskeletons of marine crustaceans) was used to estimate antibacterial activity . Approximately 2 logcolony forming units (CFU)/ml of A . actinomycetemcomitans were inactivated by 0.1% chitosan after 30 min, while 120 min exposure inactivated about 4.5 logCFU/ml of this organism . In contrast, the level of inactivation against S . mutans was less than 0.5 logCFU/ml after an exposure of up to 120 min . Electron microscopy showed that the exposure of A . actinomycetemcomitans to the chitooligosaccharides resulted in the disruption of cell membranes and that it could be considered for the treatment of periodontal diseases associated with A . actinomycetemcomitans. Int J Antimicrob Agents, 2001 Dec, 18(6), 531 - 5 In vitro activity of ABT-773, telithromycin and eight other antimicrobials against erythromycin-resistant Streptococcus pneumoniae respiratory isolates of children; Johnson CN et al.; The activity of the ketolide ABT-773 against 180 erythromycin-resistant Streptococcus pneumoniae obtained from children was compared with telithromycin, azithromycin, clarithromyin, roxithromycin, clindamycin, penicillin, levofloxacin and gatifloxacin . Ketolide MICs were all < or =1 mg/l, with ABT-773 being the most potent of all drugs tested . MIC(90)s for macrolides and azithromycin in mefE+ isolates were 16-32 compared with >128 mg/l for ermB+ isolates . ABT-773 and telithromycin MIC(90)s for mefE+ isolates were 0.125 and 0.5, compared with 0.032 and 0.016 mg/l for ermB+ isolates and 0.5 and 1 mg/l, respectively, for isolates containing both genes . Clindamycin was active against mefE+ but not ermB+ isolates . 155 isolates were resistant to penicillin . All fluoroquinolone MICs were < 1 mg/l . Further studies of ketolides for treatment of paediatric S . pneumoniae infections are warranted. Mol Microbiol, 2001 Nov, 42(4), 1035 - 45 Constitutive competence for genetic transformation in Streptococcus pneumoniae caused by mutation of a transmembrane histidine kinase; Lacks SA et al.; Competence for DNA uptake and genetic transformation in Streptococcus pneumoniae is regulated by a quorum-sensing system . A competence-stimulating polypeptide (CSP) is secreted by the bacteria and acts back on the cells via a transmembrane histidine kinase . This enzyme phosphorylates a response regulator that activates synthesis of a SigH-like protein . The new sigma factor enables expression of a set of proteins transcribed from a novel promoter . A mutation called trt had been found that circumvented this regulation . The mutant cells are constitutively competent; that is, they can be transformed at low cell densities, in the presence of proteases that attack CSP, or during growth at low pH . In this work, cells containing trt were shown to be competent even in the presence of a comAB mutation that blocks secretion of CSP . The trt mutation was localized to comD, the gene encoding the transmembrane histidine kinase . A DNA segment of the trt mutant corresponding to comCDE was cloned, and it was shown to contain the trt mutation by its ability to confer constitutive competence . A two-step assay, which was based on transfer of trt to a wild strain and screening for transformability in the presence of trypsin, served to locate the trt mutation precisely . It corresponds to a GC-->AT transition, which changes Asp299 in the histidine kinase to Asn . This alteration in the carboxyl terminal half of the protein, which is cytoplasmically located and contains the phosphorylase activity, presumably alters the enzyme conformation so that it is permanently activated, independent of signals from the transmembrane domain . These results may help illuminate the mechanism by which external signals affect kinase action in two-component regulatory systems, and they may be of practical value in facilitating genetic studies by rendering pneumococcal strains permanently competent. Clin Oral Implants Res, 2001 Dec, 12(6), 543 - 51 Plaque formation on surface modified dental implants . An in vitro study; Grossner-Schreiber B et al.; Bacterial adhesion on titanium implant surfaces has a strong influence on healing and lon