J Biol Chem, 1999 Jul 2, 274(27), 18942 - 6 Inactivated pbp4 in highly glycopeptide-resistant laboratory mutants of Staphylococcus aureus; Sieradzki K et al.; Both vancomycin- and teicoplanin-resistant laboratory mutants of Staphylococcus aureus produce peptidoglycans of altered composition in which the proportion of highly cross-linked muropeptide species is drastically reduced with a parallel increase in the representation of muropeptide monomers and dimers (Sieradzki, K., and Tomasz, A . (1997) J . Bacteriol . 179, 2557-2566; and Sieradzki, K . , and Tomasz, A . (1998) Microb . Drug Resist . 4, 159-168) . We now report that the distorted peptidoglycan composition is related to defects in penicillin-binding protein 4 (PBP4); no PBP4 was detectable by the fluorographic assay in membrane preparations from the mutants, and comparison of the sequence of pbp4 amplified from the mutants indicated disruption of the gene by two types of abnormalities, a 17-amino acid long duplication starting at position 305 of the pbp4 gene was detected in the vancomycin-resistant mutant, and a stop codon was found to be introduced into the pbp4 KTG motif at position 261 in the mutant selected for teicoplanin resistance . Additional common patterns of disturbances in the peptidoglycan metabolism of the mutants are indicated by the increased sensitivity of mutant cell walls to the M1 muramidase and decreased sensitivity to lysostaphin, which is a reversal of the susceptibility pattern of the parental cell walls . Furthermore, the results of high performance liquid chromatography analysis of lysostaphin digests of peptidoglycan suggest an increase in the average chain length of the glycan strands in the peptidoglycan of the glycopeptide-resistant mutants . The increased molar proportion of muropeptide monomers in the cell wall of the glycopeptide-resistant mutants should provide binding sites for the "capture" of vancomycin and teicoplanin molecules, which may be part of the mechanism of glycopeptide resistance in S . aureus. J Antimicrob Chemother, 1999 May, 43(5), 737 - 40 Efficacy and pharmacodynamics of teicoplanin given daily during the first 3 days and then on alternate days for methicillin-resistant Staphylococcus aureus infections; Bantar C et al.; Fifteen evaluable patients (mean age, 67 years) were enrolled to assess the efficacy of teicoplanin, 6 mg/kg given daily during the first 3 days and then on alternate days, for the treatment of methicillin-resistant Staphylococcus aureus (MRSA) infections . Eight patients had soft tissue infections, four catheter-associated bacteraemia, two osteomyelitis and one pneumonia . Clinical cure was observed in 13 of 15 patients . Both clinical and bacteriological failures were shown in the two patients with osteomyelitis . The mean serum levels of teicoplanin (mg/L) were 22, 8 and 6.7 for peak, 24 h and 48 h troughs, respectively . The dosage employed in this study proved effective in non-deep-seated MRSA infections. J Antimicrob Chemother, 1999 May, 43(5), 729 - 31 Reduced susceptibility to vancomycin of nosocomial isolates of methicillin-resistant Staphylococcus aureus; Kantzanou M et al.; The MICs of vancomycin for 56 random nosocomial Staphylococcus aureus isolates homogeneously resistant to methicillin (homMRSA), 16 heterogeneously resistant isolates (hetMRSA) and 25 susceptible isolates (MSSA) were determined by a standard broth microdilution method . Representative isolates were also tested by an agar incorporation method, the Etest and population analysis . Although always in the susceptible range, MICs of vancomycin for homMRSA were significantly higher than those for hetMRSA or MSSA . Moreover, a homMRSA strain belonging to one of the major Greek MRSA clones contained a sub-population of cells that could grow in the presence of vancomycin 8 mg/L at a frequency of 6.7 x 10(-8). J Antimicrob Chemother, 1999 May, 43 Suppl B, 31 - 7 The effect of moxifloxacin on its target topoisomerases from Escherichia coli and Staphylococcus aureus; Schedletzky H et al.; The effect of moxifloxacin on its target enzymes was evaluated by three different approaches: (i) the MICs of moxifloxacin and nine other fluoroquinolones were determined for mutants of Escherichia coli (n = 13) and Staphylococcus aureus (n = 5) carrying different combinations of resistance mutations; (ii) the activity of moxifloxacin on isolated targets was determined as IC50 values for wild-type and mutant type II topoisomerases from E . coli; and (iii) the mutation frequencies were determined for two single-step mutants (MI with a Ser83-->Leu mutation in gyrA and WT-4 with a Ser80-->Ile mutation in parC) and their parent strain (WT) . Of the quinolones tested, moxifloxacin was the only one showing an equivalent high activity against both targets . This is reflected by a comparable high susceptibility of the test strains of E . coli and S . aureus and by the IC50 values of moxifloxacin which were 50-90% lower than those of ciprofloxacin, norfloxacin and sparfloxacin for the wild-type and single mutant enzymes of gyrase and topoisomerase IV . However, double mutant GyrA was significantly more sensitive to moxifloxacin than to the other fluoroquinolones tested, while wild-type topoisomerase IV was two-fold more refractory . Mutation rates of WT, MI and WT-4 for ciprofloxacin and moxifloxacin were 5 x 10(-8) vs 4 x 10(-10); <6 x 10(-11) vs <6 x 10(-11); and 2 x 10(-6) vs 5 x 10(-7), respectively . These data indicate an equivalent high inhibitory activity of moxifloxacin on DNA gyrase and topoisomerase IV of E . coli. J Food Prot, 1999 Jun, 62(6), 644 - 9 Bacterial contamination of ready-to-eat foods and fresh products in retail shops and food factories; Kaneko KI et al.; Raw vegetables cut for salad, cooked salad, cooked rice, boiled noodles, bean curd, and cooked Japanese foods were purchased in 27 retail shops in Tokyo . Intact vegetables before being processed and ready-to-eat fresh salad products were obtained from two food factories located in the suburbs of Tokyo . Two hundred thirty-eight retail samples, 137 samples of intact vegetables, and 159 samples of fresh products were examined for aerobic plate count (APC), coliforms, Escherichia coli, Listeria spp., Staphylococcus aureus, and Bacillus cereus . The APC of retail foods were 2.1 to 5.7 log CFU/g, and the range for the coliforms was 0.1 to 2.3 log CFU/g . The APC and coliform values showed that the raw vegetables cut for salad were the most heavily contaminated among the six kinds of ready-to-eat foods examined . Although L . monocytogenes was not detected, two samples of raw vegetables and five kinds of cooked foods yielded Listeria spp . S . aureus was detected in one sample of Japanese cooked food . The APC of the intact vegetables were 2.9 to 7.3 log CFU/g upon arrival and 2.2 to 7.2 log CFU/g after 3 days storage at 10 degrees C . The APC of the fresh products were 3.4 to 7.6 log CFU/g upon arrival and 4.7 to 8.7 log CFU/g after 3 days storage at 10 degrees C . The isolation rates for coliforms were 6.1 to 50% for intact vegetables and 50 to 66.7% for fresh products . E . coli was detected only in the fresh products . B . cereus was isolated from 20.1% (17 of 81) of the intact vegetables and 9.2% (8 of 87) of the fresh products. J Biomol NMR, 1999 May, 14(1), 85 - 8 {13C}-constant-time {15N,1H}-TROSY-HNCA for sequential assignments of large proteins; Salzmann M et al.; The greatly improved sensitivity resulting from the use of TROSY during 15N evolution and amide proton acquisition enables the recording of HNCA spectra of large proteins with constant-time 13C alpha evolution . In {13C}-ct-{15N,1H}-TROSY-HNCA experiments with a 2H/13C/15N-labeled 110 kDa protein, 7,8-dihydroneopterin aldolase from Staphylococcus aureus, nearly all correlation peaks seen in the {15N,1H}-TROSY-HNCA spectrum were also detected . The improved resolution in the 13C dimension then enabled a significant number of sequential assignments that could not be obtained with {15N,1H}-TROSY-HNCA without {13C}-constant-time period. Pediatr Radiol, 1999 May, 29(5), 367 - 71 MRI evaluation of infectious and non-infectious synovitis: preliminary studies in a rabbit model; Strouse PJ et al.; BACKGROUND: Literature on magnetic resonance imaging (MR) evaluation of inflammatory joint effusions is sparse . OBJECTIVE: To describe an animal model for studying infectious and non-infectious joint effusions with magnetic resonance imaging . MATERIALS AND METHODS: Ten rabbit knees with septic arthritis and four with talc synovitis were imaged with MR . Contralateral knees injected with saline served as controls . Fat saturation T2-weighted and gadolinium-enhanced T1-weighted images were assessed for joint effusion, and periarticular and adjacent intraosseous increased signal or enhancement . Each knee was cultured and underwent pathologic examination . RESULTS: Both Staphylococcus aureus and talc produced effusions in all knees . The degree of periarticular signal and enhancement was greater in infected knees than talc-injected knees . No abnormal enhancement was seen within bone . Pathologic examination showed a greater degree of inflammation and joint destruction in the infected knees, but no evidence of osteomyelitis . CONCLUSION: A greater degree of abnormal signal and enhancement seen on MR suggests a more vigorous inflammatory process, as seen with septic arthritis . In spite of advanced septic arthritis, no enhancement was evident within bone, suggesting that enhancement within bone is not an expected finding in isolated septic arthritis and should raise concern for osteomyelitis. Biochem Biophys Res Commun, 1999 Jun 24, 260(1), 111 - 6 Functional mimicry of protein A of Staphylococcus aureus by a proteolytically cleaved fragment; Sinha P et al.; Protein A (PA) of Staphylococcus aureus has an array of biological functions, such as antitumor, antitoxic, anticarcinogenic, immunomodulatory, antifungal, and antiparasitic properties . We have already established that a theoretical trypsin-digested peptide fragment of protein A (20-mer) mimics immunomodulatory and IgG binding property of PA . In the present report we have concentrated on a 16-mer chymotryptic fragment of protein A, which has a sequence of 13 amino acids in common with the previously studied 20-mer peptide . Molecular modeling study qualitatively predicted that both 20-mer and 16-mer peptides retain Fc binding ability from an interaction energy point of view . In the present study our aim was to understand whether this theoretically predicted 16-mer chymotryptic fragment could be formed in a real experiment and also to understand its biological activities . Chymotrypsin cleavage of PA at 37 degrees C for 24 h produced four major fragments on reverse-phase HPLC . The amino acid analyses of each fragment show the absence of cysteine residue from all fragments, which justifies the absence of cysteine in PA . We also observed high content of aspartic acid and glutamic acid residues in all fragments . On gel-filtration chromatography the chymotrypsin cleavage of PA shows five peaks, one of which overlaps with our theoretically selected 16-mer peptide on superimposition . We verified the IgG binding capacity of 16-mer peptide by capillary electrophoresis . The 16-mer peptide also induces the production of TNFalpha and IL-1alpha in serum of mice . The above observations suggest that the 16-mer peptide may be produced by chymotrypsin cleavage and also that this peptide possesses some of the major biological properties of PA, such as IgG binding, TNFalpha and IL-1alpha elicitation, etc . Biochem Biophys Res Commun, 1999 Jun 24, 260(1), 105 - 10 Induction of cell proliferation and apoptosis: dependence on the dose of the inducer; Das T et al.; Protein A (PA) of Staphylococcus aureus is known as an immunomodulator . In a search of the molecular mechanism(s) of PA-induced immunocyte potentiation, we found dose-dependent binding of PA (0.01 to 100 microg/ml PA) to the mice splenic lymphocytes . Interestingly, treatment of 1 microg PA/20 g mice increased the splenic lymphocyte number approximately 5-fold over control but at a 10-microg dose the cell number was decreased compared with a 1-microg dose . Flow cytometric analysis of cell-cycle phase distribution of nuclear DNA in splenic lymphocytes showed that at a 1-microg dose, PA shifted the cell-cycle phases from G0/G1 to S and G2/M supporting the pro-proliferative role of PA . In contrast, the same inducer increased the sub-G1 cell population at a 10-microg dose indicating the breakdown of cellular DNA . These findings were supported by DNA ladder formation and nuclear breakdown at this higher dose . Further studies revealed that at a 1-microg dose, the level of the pro-proliferative/anti-apoptotic protein bcl-2 was increased in splenic lymphocytes whereas at a 10-microg dose it showed a decreasing trend . In contrast, concentrations of proapoptotic proteins, p53 and bax, were increased at a 10-microg dose . A search of the mechanism(s) of such differential action of PA at these two doses revealed that the lower dose of PA upregulated the production of interferon-gamma (IFN-gamma) and tumor necrosis factor-alpha (TNF-alpha) to the extent which has already been reported by our laboratory to be beneficial to the host . However, at a larger dose, much higher release of TNF-alpha and interleukin-2 (IL-2) may account for the apoptosis of splenic cells . All these findings indicated that the cross-talk between all these pro- and anti-apoptotic factors may contribute to maintain a balance between growth and death of cells and may be one of the important factors deciding whether a cell would follow a proliferative pathway or an apoptotic pathway . Scand J Infect Dis, 1999, 31(1), 98 - 100 Primary sternal osteomyelitis and septicaemia due to Staphylococcus aureus; Mofredj A et al.; Primary sternal osteomyelitis is rare in these recent decades . Only scattered cases have been reported, most of them in intravenous drug users . We report the case of an 88-y-old woman who presented a primary sternal infection due to Staphylococcus aureus associated with secondary septicaemia . The only predisposing factor was radiotherapy for a malignant tumour of the right mammary gland 20 y ago . Diagnostic evaluation and therapeutic management are briefly discussed. J Antimicrob Chemother, 1999 Jan, 43(1), 113 - 8 The clinical efficacy of continuous-infusion flucloxacillin in serious staphylococcal sepsis; Leder K et al.; Since the efficacy of beta-lactams against pathogens such as methicillin-susceptible Staphylococcus aureus (MSSA) is related to the time for which serum drug concentrations exceed the MIC for the pathogen, administration of anti-staphylococcal beta-lactams by continuous infusion may provide a more suitable means of drug delivery than intermittent dosing . To assess the clinical efficacy of continuous-infusion therapy, we reviewed the outcomes for 20 consecutive patients with proven serious MSSA sepsis (three with endocarditis, ten osteomyelitis, one endocarditis plus osteomyelitis and six deep abscess) treated with continuous-infusion flucloxacillin (8-12 g/day) . Patients initially receiving routine intermittent-dose flucloxacillin therapy were changed to continuous-infusion flucloxacillin (mean duration 29 days; range 4-60 days) for completion of their treatment course . In the majority of cases this was given at home . Serum flucloxacillin concentrations during continuous-infusion flucloxacillin 12 g/day were 11.5->40 mg/L (ten patients) and those during continuous-infusion flucloxacillin 8 g/day were 8->40 mg/L (five patients), these concentrations being well above the expected MIC of flucloxacillin for MSSA . Continuous-infusion flucloxacillin was well tolerated by most patients, and 14/17 patients (82%) who completed their course of continuous-infusion flucloxacillin were judged clinically and microbiologically cured at long-term follow-up (mean 67 weeks; range 4-152 weeks) . These preliminary data suggest that, following initial intermittent-dose flucloxacillin therapy, continuous-infusion flucloxacillin is an effective treatment option for serious MSSA sepsis, and forms a feasible and possibly preferable alternative to glycopeptides when considering home-based parenteral therapy for these infections . Further studies are needed to identify whether continuous-infusion flucloxacillin can entirely replace intermittent-dose therapy for such infections. J Antimicrob Chemother, 1999 Jan, 43(1), 105 - 12 Cost-effectiveness of prophylactic nasal mupirocin in patients undergoing peritoneal dialysis based on a randomized, placebo-controlled trial; Davey P et al.; The study objective was to measure the benefits of elimination of nasal carriage of Staphylococcus aureus by calcium mupirocin ointment in patients undergoing continuous ambulatory peritoneal dialysis . The design was a prospective, placebo-controlled, randomized clinical trial . The subjects were 267 patients recruited from nine renal units in Belgium, France and the UK . The main outcome measures were the rate of catheter exit site infection (ESI), rates of other infections and healthcare costs from the perspective of a hospital budget-holder . The rate of ESI caused by S . aureus was significantly reduced from one in 28.1 patient months to one in 99.3 patient months (P = 0.006) and there were also non-significant trends towards lower rates of ESI caused by any organism and peritonitis caused by S . aureus . In comparison with the placebo group, patients in the mupirocin group with ESI had lower antibiotic (P = 0.02) and hospitalization costs (P = 0.065) . However, overall costs of antibiotic treatment, for all infections combined, were not significantly different (P = 0.2) and total antibiotic costs (including mupirocin) were significantly higher in the mupirocin group (P = 0.001) . Mupirocin prophylaxis would have been cost-neutral if the rate of ESI increased to >75% in the placebo group, or if all healthcare costs increased by 40%, or if the cost of screening was reduced from Pound Sterling 15 to Pound Sterling 3 per patient, or if the cost of mupirocin treatment was reduced from Pound Sterling 93 to Pound Sterling 40 per patient year . In conclusion, savings in healthcare costs are unlikely to be sufficiently great to offset the cost of mupirocin and screening for nasal carriage of S . aureus . The decision about whether or not to implement mupirocin should depend on a local analysis of the value of preventing ESIs caused by S . aureus. Biosci Biotechnol Biochem, 1999 May, 63(5), 884 - 91 Assembly of Staphylococcus aureus leukocidin into a pore-forming ring-shaped oligomer on human polymorphonuclear leukocytes and rabbit erythrocytes; Sugawara N et al.; Staphylococcal leukocidin consists of two separate proteins, LukS and LukF, which cooperatively lyse human and rabbit polymorphonuclear leukocytes and rabbit erythrocytes . Here we studied the pore-forming properties of leukocidin and the molecular architecture of the leukocidin pore . (1) Leukocidin caused an efflux of potassium ions from rabbit erythrocytes and swelling of the cells before hemolysis . However, ultimate lysis of the toxin-treated swollen erythrocytes did not occur when polyethylene glycols with hydrodynamic diameters of > or = 2.1 nm were present in the extracellular space . (2) Electron microscopy showed the presence of a ring-shaped structure with outer and inner diameters of 9 and 3 nm, respectively, on leukocidin-treated human polymorphonuclear leukocytes and rabbit erythrocytes . (3) Ring-shaped structures of the same dimensions were isolated from the target cells, and they contained LukS and LukF in a molar ratio of 1:1 . (4) A single ring-shaped toxin complex had a molecular size of 205 kDa . These results indicated that LukS and LukF assemble into a ring-shaped oligomer of approximately 200 kDa on the target cells, forming a membrane pore with a functional diameter of approximately 2 nm. Retina, 1999, 19(3), 223 - 9 Experimental prophylaxis of Staphylococcus aureus endophthalmitis after vitrectomy: the use of antibiotics in irrigating solution; Liang C et al.; PURPOSE: To test the efficacy of clindamycin and gentamicin in irrigating solution during vitrectomy to prevent experimental Staphylococcus aureus endophthalmitis . MATERIALS AND METHODS: Thirty-six New Zealand white rabbits were divided into six groups . Vitrectomy using two different irrigating solutions was followed by intravitreal injection of S . aureus: Group 1, balanced salt solution (BSS) followed by 1,000 colony-forming units (CFU) S . aureus; Group 2, BSS fortified with clindamycin, 10 microg/mL, and gentamicin, 8 microg/mL (CGBSS), followed by intravitreal injection of 1,000 CFU S . aureus; Group 3, BSS followed by 2,000 CFU S . aureus; Group 4, CGBSS followed by 2,000 CFU S . aureus; Group 5, BSS followed by 4,000 CFU S . aureus; and Group 6, CGBSS followed by 4,000 CFU S . aureus . The eyes were examined clinically after surgery . Vitreous samples were cultured and histologic studies were performed . RESULTS: Severe endophthalmitis developed in all eyes in Groups 1, 3, and 5 (not given antibiotics) . No endophthalmitis developed in Group 2 . In Group 4, five of the six eyes were normal and one eye had endophthalmitis . In Group 6, one eye had clear vitreous and fundus, three eyes had moderate vitreous haze, and the other four eyes demonstrated severe endophthalmitis . Bacterial growth in Groups 1, 2, 3, 4, 5, and 6 were 4/4, 0/4, 6/6, 1/6, 4/6, and 2/8 eyes, respectively . CONCLUSION: When 1,000 to 2,000 CFU S . aureus were injected after vitrectomy, clindamycin and gentamicin in the irrigating solution significantly diminished the intraocular inflammation and the rate of positive bacterial culture . Clindamycin and gentamicin in the irrigating solution were not significantly effective when 4,000 CFU bacteria was injected; however, the degree of inflammation was less severe than in the control group. Retina, 1999, 19(3), 218 - 22 Penetration of topical and oral ciprofloxacin into the aqueous and vitreous humor in inflamed eyes; Ozturk F et al.; PURPOSE: To assess the aqueous and vitreous penetration of ciprofloxacin after topical and combined topical and oral administration and investigate the effects of inflammation on drug penetration . METHODS: A standardized penetrating injury was made in the right eyes of 16 rabbits . Intraocular inflammation was induced by intravitreal injection of a suspension of Staphylococcus aureus in these eyes . The animals were divided into two groups according to treatment methodology: topical and topical-oral . The intact left eyes of the animals were maintained as controls . In the topical treatment group, two drops of ciprofloxacin 0.3% were instilled to both eyes every 30 minutes for 4 hours . In the topical-oral treatment group, animals were given two oral 40 mg/kg doses of ciprofloxacin at 12-hour intervals . After the last oral dose, the protocol of the topical group was applied to these eyes . Half an hour after the last drop, 100-microL samples were taken from aqueous and vitreous humor of all eyes . Drug concentrations were measured using high-pressure liquid chromatography . RESULTS: Mean aqueous levels of ciprofloxacin in control eyes were 2.31 microg/mL (range, 1.02-6.27 microg/mL) in the topical group and 5.88 microg/mL (1.52-17.81) in the topical-oral group . Mean aqueous levels in inflamed eyes were 7.36 microg/mL (2.34-17.15) in the topical group and 14.43 microg/mL (2.18-18.66) in the topical-oral group . Mean vitreous levels in control eyes were 0.77 microg/mL (0.09-1.93) in the topical group and 1.01 microg/mL (0.49-1.57) in the topical-oral group . Mean vitreous levels in inflamed eyes were 0.95 microg/mL (0.18-1.27) in the topical group and 1.98 microg/mL (0.51-3.34) in the topical-oral group . There was no significant difference among the groups (P > 0.05) . Mean aqueous levels in all eyes and mean vitreous levels in the combined topical and oral group of inflamed eyes were above the 90% minimum inhibitory concentration for most of the common microorganisms causing endophthalmitis . CONCLUSION: There is an increase in both aqueous and vitreous humor concentrations with inflammation and with oral and topical administrations, as opposed to topical only, of ciprofloxacin . Using oral as well as topical treatment may be a beneficial method of antibiotic prophylaxis in ocular trauma once a patient has received intravenous or intravitreal therapy. J Vet Med Sci, 1999 May, 61(5), 569 - 71 Effect of vitamin B2 on somatic cell counts in milk of clinical Staphylococcus aureus mastitis; Sato S et al.; Effects of intravenous injection of Vitamin B2 (VB2) on the nitroblue tetrazolium (NBT) reductivity of peripheral blood neutrophils and the somatic cell counts (SCC) in quarter milk of Staphylococcus aureus mastitis were investigated . The NBT reductivities of neutrophils were enhanced at 2 days after single injection of VB2 (5.0 and 2.5 mg/kg), and were also enhanced at 4 days after initial injection of continuous 3 days of VB2 (2.5 mg/kg) . The SCC in quarter milk were significantly decreased at 3, 7 and 14 days after initial injection of continuous 3 days of VB2 (2.5 mg/kg), however, S . aureus in the infected quarter was not cured bacteriologically by VB2 injection. Mayo Clin Proc, 1999 Jun, 74(6), 553 - 8 Staphylococcus aureus prosthetic joint infection treated with prosthesis removal and delayed reimplantation arthroplasty; Brandt CM et al.; OBJECTIVE: To estimate in patients with Staphylococcus aureus prosthetic joint infection after total hip arthroplasty (THA) or total knee arthroplasty (TKA) the microorganism-specific cumulative probability of treatment failure after prosthesis removal and delayed reimplantation arthroplasty . PATIENTS AND METHODS: All patients with S aureus THA or TKA infection, according to a strict case definition, who were treated with prosthesis removal and delayed reimplantation arthroplasty at Mayo Clinic Rochester between 1980 and 1991 were identified . The study group comprised patients who were free of infection at the time of reimplantation arthroplasty . This cohort was followed up until treatment failure, infection with another organism, prosthesis removal, death, or loss to follow-up occurred . The Kaplan-Meier survival method was used to estimate the cumulative probability of treatment failure . RESULTS: Among 120 S aureus prosthetic joint infections treated with prosthesis removal during the study period, 38 episodes (22 THA, 16 TKA) in 36 patients met the study inclusion criteria . After a median of 7.4 years (range, 0.9 year-16.4 years) of follow-up, treatment failure occurred in 1 (2.6%) of 38 episodes 1.4 years after reimplantation arthroplasty . The 5-year cumulative probability of treatment failure was 2.8% (95% confidence interval, 0%-8.2%) . CONCLUSIONS: These data suggest that prosthesis removal and delayed reimplantation arthroplasty is an effective treatment to limit the recurrence of S aureus prosthetic joint infection, provided there is no evidence of infection at the time of reimplantation arthroplasty. J Orthop Res, 1999 May, 17(3), 382 - 91 Experimental acute hematogenous osteomyelitis in mice . II . Influence of Staphylococcus aureus infection on T-cell immunity; Yoon KS et al.; A murine model of acute hematogenous osteomyelitis was used to study the immune response following Staphylococcus aureus infection and to examine the hypothesis that the bacteria may modify T-cell responses due to the production of bacterial enterotoxins with mitogenic or superantigenic activity . Lymph-node T cell-receptor expression was assessed with use of flow cytometry and reverse transcription-polymerase chain reaction techniques, and increased apoptosis (programmed cell death) in T-cell subsets was monitored . The expression and levels of circulating cytokines and T-cell cytokines within tissues surrounding the damaged area of the proximal tibia were also investigated . Analysis of T-cell receptors in experimental osteomyelitis revealed two distinct patterns of T-cell evolution during the disease . Certain T-cell subsets (Vbeta2, Vbeta3, Vbeta9, and Vbeta10) were activated and expanded during the first 24 hours after infection; they reached maximum levels 6 days after infection, followed by a return to pre-infection levels . In contrast, other T-cell subsets (Vbeta11, Vbeta12, Vbeta13, Vbeta14, and Vbeta16) contracted during the first 24 hours after infection, followed by expansion to a maximum level 9 days after infection . Activation and proliferation of T-cell subsets (notably Vbeta14 T cells) was followed by apoptosis, suggesting that staphylococcal bone infection caused superantigenic-like effects on the mouse immune system . Analysis of cytokine responses in local tissue revealed that the T-cell cytokines interleukin-2 and interferon-gamma showed a late and relatively short activation pattern compared with the inflammatory cytokines interleukin-1, interleukin-6, and tumor necrosis factor-alpha . The results suggest that Staphylococcus aureus bone infection may undermine the antibacterial immune response through downregulation of T-cell immunity and immune-cytokine production, which could increase the severity of the systemic infection and local osseous destruction that occur with acute hematogenous osteomyelitis. AORN J, 1999 Jun, 69(6), 1169 - 72, 1175-7, 1179 passim Airborne particulates in the OR environment; Edmiston CE Jr et al.; Intraoperative sampling of airborne particulates is rarely performed in the OR environment because of technical difficulties associated with sampling methodologies and because of the common belief that airborne contamination is infrequently associated with surgical site infections (SSIs) . In this study, investigators recovered non-viable (i.e., lint) and viable (i.e., microorganisms) particulates during vascular surgery using a personal cascade impactor sampling device . The predominant nonviable particulates recovered during intraoperative sampling were wood pulp fibers from disposable gowns and drapes . Several potential nosocomial pathogens (e.g., Staphylococcus aureus, Staphylococcus epidermidis) and other drug-resistant isolates frequently were recovered from an area adjacent to the surgical field . The widespread presence of airborne particulates during surgery suggests that further studies are warranted to assess the role these particles may play in the development of SSIs or in dissemination of nosocomial pathogens within the OR and hospital environment. Infect Immun, 1999 Jul, 67(7), 3667 - 9 Isolation and characterization of a sigB deletion mutant of Staphylococcus aureus; Nicholas RO et al.; The sigB gene of Staphylococcus aureus, coding for the alternate sigma factor B, has been deleted by allelic replacement mutagenesis . The mutant grew as well as the parent in vitro, although it was deficient in clumping factor, coagulase, and pigment . In two murine and one rat infection model the mutant showed no reduction in virulence. Infect Immun, 1999 Jul, 67(7), 3267 - 75 Innate antimicrobial activity of nasal secretions; Cole AM et al.; Minimally manipulated nasal secretions, an accessible form of airway surface fluid, were tested against indigenous and added bacteria by using CFU assays . Antimicrobial activity was found to vary between donors and with different target bacteria and was markedly diminished by dilution of the airway secretions . Donor-to-donor differences in electrophoresis patterns of nasal secretions in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (PAGE) and acid urea-PAGE analyses were readily observed, suggesting that polymorphic genes encode the secreted proteins . Three donors (of twenty-four total), whose nasal fluid yielded similar protein band patterns and did not kill indigenous bacteria, were determined to be heavy nasal carriers of Staphylococcus aureus . Their fluid was deficient in microbicidal activity toward a colonizing strain of S . aureus but the defect was corrected in vitro by a 1:1 addition of nasal fluid from noncarriers . The microbicidal activity of normal fluid was inactivated by heating it for 10 min to 100 degrees C and could not be restored solely by the addition of two major nasal antimicrobial proteins, lysozyme and lactoferrin . Several other known antimicrobial proteins and peptides, including statherin, secretory phospholipase A2, and defensins, were identified in nasal secretions and likely contribute to their total antimicrobial properties . Nasal fluid may serve as a useful model for the analysis of lower-airway secretions and their role in host defense against airway colonization and pulmonary infections. Infect Immun, 1999 Jul, 67(7), 3215 - 20 Moesin functions as a lipopolysaccharide receptor on human monocytes; Tohme ZN et al.; Bacterial endotoxin (lipopolysaccharide {LPS}), a glycolipid found in the outer membranes of gram-negative bacteria, induces the secretion of proinflammatory cytokines such as tumor necrosis factor alpha (TNF-alpha), interleukin-1 (IL-1), and IL-6 by monocytes/macrophages . The secretion of these biologically active compounds leads to multiple pathological conditions, such as septic shock . There is substantial evidence that chronic exposure to LPS mediates, at least in part, the tissue destruction associated with gram-negative infection . CD14, a 55-kDa protein, has been identified as an LPS receptor . In conjunction with a serum protein, LPS binding protein (LBP), LPS-CD14 interactions mediate many LPS functions in the inflammatory response . However, CD14 lacks a cytoplasmic domain, or any known signal transduction sequence motif, suggesting the existence of another cell surface domain capable of transducing signals . In this paper, we report a second, CD14-independent LPS binding site, which, based on biological activity, appears to be a functional LPS receptor . Cross-linking experiments were performed to identify LPS binding sites . Two molecules were identified: a 55-kDa protein (CD14) and a second, 78-kDa band . Sequencing of the 78-kDa protein by mass spectroscopic analysis revealed 100% homology with moesin (membrane-organizing extension spike protein) . Antibody to CD14 induced partial blocking of the LPS response . However, antimoesin monoclonal antibody completely blocked the LPS-induced TNF-alpha response in human monocytes, without blocking CD14 binding of LPS . Irrelevant isotype controls had no effect . Additional experiments were performed to evaluate the specificity of the antimoesin blocking . Separate experiments evaluated antimoesin effects on monocyte chemotaxis, IL-1 production in response to IL-1 stimulation, and TNF-alpha secretion in response to Staphylococcus aureus stimulation . Antimoesin blocked only LPS-mediated events . The data suggest that moesin functions as an independent LPS receptor on human monocytes . The role of moesin in transduction of CD14-mediated signals is discussed. Res Microbiol, 1999 May, 150(4), 287 - 90 HSa of Staphylococcus aureus, a new member of the HU family of bacterial histone-like proteins; Viter S et al.; Histone-like proteins of the HU family are small, sequence-independent DNA binding proteins that facilitate a variety of DNA transactions . Here we report isolation from cell-free extracts of Staphylococcus aureus of HSa, a new member of the HU family . The NH2-terminal amino acid sequence of HSa led to identification of the corresponding gene (hsa) using the genome sequence of S . aureus . HSa is 90 amino acids long (Mr = 9 620) and shares 64 to 80% identity with homologs found in the genus Bacillus. West Indian Med J, 1999 Mar, 48(1), 20 - 2 Methicillin resistant Staphylococcus aureus; Swanston WH; The prevalence of methicillin resistant Staphylococcus aureus (MRSA) at the General Hospital, Port-of-Spain, between June 1995 and May 1996 was determined . The MRSA prevalence rate was 4.6% of all S aureus isolates, with all but one nosocomially acquired . 15 isolates were associated with infections, and three were colonizing strains . 17 of the 18 patients with MRSA had received antibiotics previously, including 13 who had received multiple antibiotics . Skin and soft tissue were the sites of infection and colonization in 12 cases; and surgical wards and the Intensive Care Unit (ICU) accounted for 16 MRSA isolates . All isolates were sensitive to vancomycin and all but one were resistant to gentamicin . MRSA occurred sporadically in a wide distribution of wards and physicians' services, although the isolation of three strains from the ICU and three strains from a surgical ward were temporally related . Only one of two deaths was attributable to MRSA . Control of the spread of MRSA in this hospital must include the reinforcement of the appropriate use of antibiotics, hand washing and appropriate isolation of patients in the surgical and intensive care wards. Biol Pharm Bull, 1999 May, 22(5), 463 - 70 Inhibitory effect of polyoxotungstates on the production of penicillin-binding proteins and beta-lactamase against methicillin-resistant Staphylococcus aureus; Fukuda N et al.; In our continuous work on the enhancement of the antibacterial activity of beta-lactam antibiotics against the cells of methicillin-resistant Staphylococcus aureus (MRSA) strains by Keggin-structural polyoxotungstates and their lacunary species, Wells-Dawson, double-Keggin, and Keggin-sandwich polyoxotungstates are also found to be synergistic but highly cytotoxic . The coexistence of polylysine or protamine sulphate decreased the synergistic potency of the polyoxotungstates, due to their electrostatic interaction with negatively charged polyoxotungstates . Inductively coupled plasma atomic emission spectrometry (ICP) analysis of the polyoxotungstate-treated cells indicated that the polyoxotungstates uptaken in the cell are preferentially located at the membrane fraction with intact composition . The polyoxotungstates depressed not only the production of PBP2', but also the production of beta-lactamase which hydrolyzes beta-lactam antibiotics on the membrane . This leads to the synergistic effect of polyoxotungstates against the MRSA cells in the coexistence of beta-lactam antibiotics which have high affinities to PBPs 1-4 . MRSA cells which were modified to be susceptible to beta-lactam antibiotics during incubation in the presence of polyoxotungstates recovered their resistance to beta-lactam antibiotics when they were subcultured in the absence of the polyoxotungstate. J Cataract Refract Surg, 1999 Jun, 25(6), 753 - 62 Simultaneous bilateral cataract extraction; Ramsay AL et al.; PURPOSE: To evaluate the visual outcome and safety of simultaneous bilateral cataract extraction . SETTING: Stobhill Hospital NHS Trust, Glasgow, United Kingdom . METHODS: This retrospective case review comprised 259 consecutive patients (518 eyes) who had simultaneous bilateral cataract surgery . Surgeries included bilateral extracapsular procedures, uniocular extracapsular procedures performed simultaneously with a different type of intraocular lens surgery in the other eye, and 1 bilateral intracapsular procedure . Outcome measures were postoperative best spectacle-corrected visual acuity (BSCVA), intraoperative and postoperative complication rates, and conjunctival swab culture results . RESULTS: Eighty-three percent of patients (75% of eyes) with measured preoperative and postoperative BSCVA achieved an acuity of 6/12 or better . Intraoperative and postoperative complication rates were similar to those in previous reports of unilateral extracapsular surgery and simultaneous bilateral cataract surgery . Endophthalmitis occurred in 1 eye (0.19%) . There were no bilateral complications that resulted in visual loss . Cultures were positive from 42% of conjunctival swabs; 81% of positive cultures were coagulase-negative Staphylococcus and 10% were Staphylococcus aureus . CONCLUSIONS: Simultaneous bilateral cataract surgery did not lead to an increased incidence of serious intraoperative or postoperative complications, and visual acuity results were good. Curr Eye Res, 1999 May, 18(5), 358 - 62 Clarithromycin for experimental Staphylococcus aureus keratitis; Hume EB et al.; PURPOSE: Clarithromycin, a macrolide antibiotic not previously tested against the common causes of bacterial keratitis, was analyzed for its effectiveness in reducing the number of viable bacteria in a Staphylococcus keratitis model . An in vivo comparison of the effectiveness of clarithromycin to erythromycin, minocycline, and tetracycline for three strains of Staphylococcus aureus was done . METHODS: Rabbit eyes were intrastromally injected with 100 colony forming units of one of three strains of S . aureus . Two strains were methicillin-sensitive (ATCC 25923 and MSSA 309) and one strain methicillin-resistant (COL) . Eyes were treated every 30 minutes with 0.3% clarithromycin, erythromycin, tetracycline, or minocycline from 4 to 9 hours postinfection . The number of colony forming units (CFU) per cornea in all eyes was determined at 10 hours postinfection . RESULTS: Vehicle-treated and untreated eyes (controls) contained over 6 logs of CFU per cornea, a value significantly higher than any of the antibiotic-treated eyes (P < or = 0.0001) . Clarithromycin or erythromycin therapy significantly decreased the number of CFU per cornea by approximately 5 logs in the eyes infected with the methicillin-sensitive strains and by approximately 4 logs in the eyes infected with the methicillin-resistant strain . Tetracycline and minocycline were also successful in treating these strains, but overall showed less effectiveness than clarithromycin and erythromycin . CONCLUSIONS: Clarithromycin proved to be an effective ocular medication for the therapy of experimental S . aureus keratitis . The effectiveness of clarithromycin in this model and its known effectiveness for a variety of bacterial pathogens suggests a role for this drug as a useful ocular antibiotic. J R Coll Surg Edinb, 1999 Jun, 44(3), 161 - 3 Surgical patients with methicillin resistant staphylococcus aureus infection: an analysis of outcome using P-POSSUM; Menon KV et al.; The significance of MRSA infection in surgical patients was studied using the P-POSSUM scoring system . All surgical patients undergoing operation between 1/10/96 and 30/09/97 were prospectively scored using P-POSSUM . A subset of these patients with MRSA infection was analysed using P-POSSUM predicted mortality . Physiological and operative severity scores were compared with non-MRSA surgical patients and length of hospital stay with P-POSSUM matched non-MRSA controls . Thirty of the 1,132 patients were MRSA positive and of these five died, giving a P-POSSUM observed/expected deaths ratio of 1.7 (not significant; 95% CI -0.24 to 0.10) . The P-POSSUM physiology score of 30 MRSA positive patients, compared with the non-MRSA group (n = 1102), was significantly more severe (20.9 v/s 17.4; 95% CI 1.09 to 5.95) as was the operative severity score (15.6 v/s 9.2; 95% CI 4.40 to 8.42) . The length of stay for surviving MRSA positive patients was significantly longer than P-POSSUM matched controls . MRSA infection in surgical patients does not increase mortality . However, patients who contract MRSA infection are more debilitated and have undergone a greater surgical insult. Nat Med, 1999 Jun, 5(6), 702 - 5 Intra-articularly localized bacterial DNA containing CpG motifs induces arthritis; Deng GM et al.; Unmethylated CpG motifs are often found in bacterial DNA, and exert immunostimulatory effects on hematopoietic cells . Bacteria produce severe joint inflammation in septic and reactive arthritides; bacterial DNA may be involved in this process . We injected bacterial DNA originating from Escherichia coli and Staphylococcus aureus and oligonucleotides containing CpG directly into the knee joints of mice of different strains . Arthritis was seen by histopathology within 2 hours and lasted for at least 14 days . Unmethylated CpG motifs were responsible for this induction of arthritis, as oligonucleotides containing these motifs produced the arthritis . The arthritis was characterized by an influx of monocytic, Mac-1+ cells and by a lack of T lymphocytes . Depletion of monocytes resulted in abrogation of the synovial inflammation . Tumor necrosis factor (TNF)-alpha, a cytokine produced by cells of the monocyte/macrophage lineage, is an important mediator of this disease, as expression of mRNA for TNF-alpha was evident in the inflamed joints, and the CpG-mediated inflammation was abrogated in mice genetically unable to produce this cytokine . These findings demonstrate that bacterial DNA containing unmethylated CpG motifs induces arthritis, and indicate an important pathogenic role for bacterial DNA in septic arthritis. Arch Intern Med, 1999 Jun 14, 159(11), 1244 - 7 Staphylococcus aureus bacteremia among elderly vs younger adult patients: comparison of clinical features and mortality; McClelland RS et al.; BACKGROUND: Previous studies give conflicting results regarding the effect of age on outcomes in Staphylococcus aureus bacteremia (SAB) . These studies have been limited by retrospective design or small sample size . METHODS: We conducted a prospective cohort study of 385 patients with SAB aged 18 to 90 years . The setting was a large academic medical center . We observed patients from diagnosis of SAB to discharge or death . Discharged patients were contacted 12 weeks after their first positive culture findings . Data were collected on demographics, comorbid conditions, focus of infection, length of stay, and outcome . Primary outcomes were total mortality and death due to SAB . RESULTS: Comparisons were made between 145 patients, aged 66 to 90 years, and 240 patients, aged 18 to 60 years . Forty-three (29.7%) of the elderly patients and 36 (15%) of the younger patients died . Death directly attributable to SAB occurred in 21 (14.5%) older and 15 (6.3%) younger patients . After adjusting for confounding variables, older patients continued to have higher total mortality (odds ratio, 2.21; 95% confidence interval, 1.32-3.70), and higher mortality from SAB (odds ratio, 2.30; 95% confidence interval, 1.13-4.69) . Infection with methicillin-resistant S aureus was associated with higher total mortality in the elderly (odds ratio, 2.59; 95% confidence interval, 1.23-5.43) . CONCLUSIONS: Staphylococcus aureus bacteremia among the elderly is associated with high mortality . Both total mortality and mortality directly attributable to SAB are more than twice as likely in older patients . Infection with methicillin-resistant S aureus carries a worse prognosis than infection with methicillin-sensitive S aureus in the elderly. Pflugers Arch, 1999 Jul, 438(2), 218 - 23 The role of tumour necrosis factor-alpha (TNF-alpha) in fever and the acute phase reaction in rabbits; Mabika M et al.; We investigated the role of tumour necrosis factor-alpha (TNF-alpha) in fever and the acute phase reaction using a specific type-IV phosphodiesterase inhibitor, rolipram, that inhibits the production of TNF-alpha . The body temperatures and serum iron concentrations of rabbits were measured following injections of lipopolysaccharide (LPS) or Staphylococcus aureus (S . aureus) with either rolipram, diclofenac sodium or the appropriate control solutions . Rolipram significantly (P<0.05) inhibited the first phase of both LPS and Staphylococcal fever, but had no effect on the second phase . The fall in serum iron concentration was not significantly affected by the injection of rolipram together with LPS or S . aureus . These results suggest that TNF-alpha is a pyrogen that plays a role during the first phase of fever, at least . However, TNF-alpha appears not to mediate the fall in serum iron concentration during the acute phase reaction. Immunol Lett, 1999 Apr 15, 67(3), 157 - 65 Protein A of Staphylococcus aureus evokes Th1 type response in mice; Sinha P et al.; Protein A (PA) of Staphylococcus aureus is known to elicit several cytokines such as IFN gamma, TNF alpha and IL1 . However, it has not been delineated yet as to which differentiation pathway lymphocytes follow after stimulation by PA . In this report, we attempted to collect such evidences . Cytokines, such as IFN gamma, IL2, IL4, IL6, IL10, TNF alpha, IL1alpha and IL1beta were measured in serum by ELISA . Our results show that 1 microg dose of PA stimulates the production of IFN gamma (115 +/- 5 pg/ml), TNF alpha (250 +/- 8 pg/ml) and IL1alpha (100 +/- 5 pg/ml) as compared to control levels of, 22 +/- 2, 20 +/- 2 and 35 +/- 3 pg/ml respectively whereas IL2 and IL1beta secretion were less (beyond the lower detection limit of the kit and 25 +/- 1 pg/ml, respectively) as compared to control (28 +/- 2 and 52 +/- 4 pg/ml, respectively) . Larger dose of PA (10 microg) increases the expression of IL2 (75 +/- 3 pg/ml), TNF alpha (1380 +/- 120 pg/ml), IL1alpha (495 +/- 10 pg/ml) and IL1beta (110 +/- 7 pg/ml) as compared to controls described above . We also observed that 1 microg dose of PA decreases IL4, IL6 and IL10 secretion to 9 +/- 1, 10 +/- 1 and 10 +/- 2 pg/ml, respectively, whereas 10 microg dose also decreased them to 11 +/- 1, 12 +/- 2 and 30 +/- 4 pg/ml, respectively as compared to the background controls, i.e . 50 +/- 5, 50 +/- 2 and 215 +/- 9 pg/ml respectively . The ratio of IFN gamma to IL4 increased and the peak value at 4 h, came to 13 +/- 1 and 9.6 +/- 0.5 with 1 microg and 10 microg PA, respectively, which is an established parameter indicating a Th1 type response . Flow cytometry analysis of CD4+/CD8+ cells, and c-myc protein expression by splenocytes indicate that 1 microg dose of PA causes 2-fold increase of CD4+ cells with no change in CD8+ cells, and 10-fold increase in c-myc protein, whereas 10 microg dose increases CD4+ cells 4-fold, CD8+ cells 3-fold and c-myc protein 100-fold . The cell cycle data shows an induction of apoptosis in thymocytes and splenocytes with the large dose (10 microg), whereas the 1 microg dose does not show any apoptosis . This report indicates that a Th1 response is induced in mice, after PA inoculation at a dose of 1 microg animal . Thus, cytokine mediated therapeutic strategies should consider the fact that an induction of large concentration of some cytokines might become detrimental to the host. Ned Tijdschr Geneeskd, 1999 May 8, 143(19), 994 - 7 {Prevention of a suspected epidemic of methicillin-resistant staphylococcus aureus (MRSA) in a nursing home}; Hoebe CJ; EPIDEMIC: Following the identification of an index patient with meticillin-resistant Staphylococcus aureus (MRSA) in a Dutch nursing home with 175 residents in the south of Limburg province, the Netherlands (microbiological diagnosis obtained from a foreign laboratory), a survey was carried out to trace contacts by means of the 'ring principle' of outbreak management . If positive cultures were found in the first ring of residents the contact and source tracing was extended . According to the Dutch guidelines for MRSA in nursing homes many preventive measures were taken regarding colonised residents and employees and the cleaning of rooms . Ten days after the occurrence of the index, 29 persons, 9 employees and 20 residents, were diagnosed as colonised with MRSA . Because of this extraordinary count compared with earlier Dutch findings (only 0.16% of inhabitants colonised) there were doubts about the laboratory results . A counter expertise from a Dutch lab and the National Institute of Health and Environmental Hygiene showed no MRSA, but meticillin-sensitive S . aureus . DISCUSSION: This alleged epidemic had very aggravating consequences for residents and employees and large financial consequences for the nursing home . There was a good reaction to the crisis by a multidisciplinary team with external specialists . The Inspectorate of Health emphasized the importance of standardized quality and interpretation of laboratory results by microbiological experts . This should be kept in mind when contracting foreign laboratories specially because the Dutch policy is to strictly avoid MRSA in intramural setting . Verification of diagnosis proved again to be an essential step in outbreak management. Structure Fold Des, 1999 Mar 15, 7(3), 277 - 87 The structure of a Staphylococcus aureus leucocidin component (LukF-PV) reveals the fold of the water-soluble species of a family of transmembrane pore-forming toxins; Pedelacq JD et al.; BACKGROUND: Leucocidins and gamma-hemolysins are bi-component toxins secreted by Staphylococcus aureus . These toxins activate responses of specific cells and form lethal transmembrane pores . Their leucotoxic and hemolytic activities involve the sequential binding and the synergistic association of a class S and a class F component, which form hetero-oligomeric complexes . The components of each protein class are produced as non-associated, water-soluble proteins that undergo conformational changes and oligomerization after recognition of their cell targets . RESULTS: The crystal structure of the monomeric water-soluble form of the F component of Panton-Valentine leucocidin (LukF-PV) has been solved by the multiwavelength anomalous dispersion (MAD) method and refined at 2.0 A resolution . The core of this three-domain protein is similar to that of alpha-hemolysin, but significant differences occur in regions that may be involved in the mechanism of pore formation . The glycine-rich stem, which undergoes a major rearrangement in this process, forms an additional domain in LukF-PV . The fold of this domain is similar to that of the neurotoxins and cardiotoxins from snake venom . CONCLUSIONS: The structure analysis and a multiple sequence alignment of all toxic components, suggest that LukF-PV represents the fold of any water-soluble secreted protein in this family of transmembrane pore-forming toxins . The comparison of the structures of LukF-PV and alpha-hemolysin provides some insights into the mechanism of transmembrane pore formation for the bi-component toxins, which may diverge from that of the alpha-hemolysin heptamer. Jpn J Antibiot, 1999 Mar, 52(3), 268 - 77 {Combination effect of teicoplanin and panipenem on highly resistant strains of MRSA}; Utsui Y et al.; We investigated the in vitro combination effect of teicoplanin (TEIC) and panipenem (PAPM) on highly oxacillin-resistant strains of Staphylococcus aureus (MRSA) isolated from various clinical specimens . Combination of TEIC and PAPM using checkerboard titration technique by agar dilution exhibited an excellent effect with mean fractional inhibitory concentration index of 0.18 +/- 0.07 on 47 MRSA strains, and the effects were judged as synergistic against all of the strains tested . In the combination of TEIC and PAPM at 1/4 MIC each against exponentially growing cells of MRSA, good bactericidal activity was found when TEIC and PAPM were added simultaneously, and PAPM was added at 1 or 2 hours prior to addition of TEIC, although the bactericidal activity was scarcely demonstrated when TEIC was added at 1 or 2 hours prior to addition of PAPM . Bactericidal activity against MRSA was enhanced in the combination of TEIC and PAPM at 1/4 MIC each for MRSA than the bactericidal activity of TEIC at 1 MIC alone . TEIC alone showed no bactericidal activity against P . aeruginosa in the mixed cultures with MRSA, while strong bactericidal activity against P . aeruginosa was induced by PAPM . In vitro bactericidal activities against mixed cultures of MRSA with P . aeruginosa were evaluated under conditions of concentrations of TEIC and PAPM, alone and in combination, whose plasma concentrations in human were simulated by a pharmacokinetic simulation model . Bactericidal activity against MRSA was enhanced by the combination of TEIC at 200 mg twice or once daily with PAPM at 500 mg twice daily in comparison with the bactericidal activity of each antibiotic alone, and P . aeruginosa was killed by the antibacterial activity of PAPM. Acta Orthop Scand, 1999 Apr, 70(2), 199 - 202 Acute spinal epidural abscess without concurrent spondylodiscitis . Successful closed treatment in 10 cases; Ahl T et al.; We performed a retrospective survey of the clinical records and radiological examinations of 10 patients with a diagnosis of spinal epidural abscess, without spondylodiscitis . All patients had an acute onset of fever and local or radiating back pain . 3 patients had mild, and 1 patient severe neurological symptoms . The diagnosis and subsequent regression of the abscess after treatment were verified by MRI . In all cases, the imaging findings included signs of septic arthritis in an adjoining facet joint . 7/10 abscesses were located in the lumbar region . Blood cultures showed Staphylococcus aureus as the etiological agent in 8/10 patients . In 2 cases, no agent was found, probably due to ongoing antibiotic therapy when the cultures were taken . All patients were treated successfully using antibiotics alone, with complete regression of the neurological symptoms. Ann Intern Med, 1999 May 18, 130(10), 810 - 20 Cost-effectiveness of transesophageal echocardiography to determine the duration of therapy for intravascular catheter-associated Staphylococcus aureus bacteremia; Rosen AB et al.; BACKGROUND: The appropriate duration of therapy for catheter-associated Staphylococcus aureus bacteremia is controversial . Conventional practice dictates that all patients receive prolonged courses of intravenous antibiotics . Some clinicians recommend abbreviated therapeutic courses, but an alternate approach involves prospectively identifying patients for whom abbreviated therapy is appropriate . OBJECTIVE: To determine the cost-effectiveness of transesophageal echocardiography (TEE) in establishing duration of therapy for catheter-associated S . aureus bacteremia . DESIGN: Cost-effectiveness analysis . DATA SOURCES: MEDLINE search of literature; clinical data from patients with S . aureus bacteremia (n = 196) and patients with endocarditis (n = 60); and costs obtained from the study institution, regional home health agency, and national estimates of professional and technical fees . TARGET POPULATION: Patients with catheter-associated S . aureus bacteremia on native heart valves without intravenous drug use or clinically apparent metastatic infection, immunosuppression, or indwelling prosthetic devices . TIME HORIZON: Patient lifetime . PERSPECTIVE: Societal . INTERVENTIONS: Antibiotic treatment based on TEE results compared with 2- or 4-week empirical therapy . OUTCOME MEASURES: Quality-adjusted life expectancy, costs, and incremental cost-effectiveness ratios . RESULTS OF BASE-CASE ANALYSIS: Compared with empirical short-course therapy, the TEE strategy cost $4938 per quality-adjusted life-year (QALY) gained . The effectiveness of the TEE strategy and the effectiveness of the long-course strategy were sufficiently similar that the additional cost of empirical long-course therapy ($1,667,971 per QALY) was higher than that which society usually considers cost-effective . RESULTS OF SENSITIVITY ANALYSES: In a four-way sensitivity analysis (endocarditis prevalence, TEE cost, short-course relapse rate, and TEE specificity), compared with empirical short-course therapy, the TEE strategy results ranged from cost savings to $155,624 per QALY . CONCLUSION: Within the limitations of existing empirical data, this study suggests that for patients with clinically uncomplicated catheter-associated S . aureus bacteremia, the use of TEE to determine therapy duration is a cost-effective alternative to 2- or 4-week empirical therapy. Philos Trans R Soc Lond B Biol Sci, 1999 Apr 29, 354(1384), 721 - 38 Studies of antibiotic resistance within the patient, hospitals and the community using simple mathematical models; Austin DJ et al.; The emergence of antibiotic resistance in a wide variety of important pathogens of humans presents a worldwide threat to public health . This paper describes recent work on the use of mathematical models of the emergence and spread of resistance bacteria, on scales ranging from within the patient, in hospitals and within communities of people . Model development starts within the treated patient, and pharmacokinetic and pharmacodynamic principles are melded within a framework that mirrors the interaction between bacterial population growth, drug treatment and the immunological responses targeted at the pathogen . The model helps identify areas in which more precise information is needed, particularly in the context of how drugs influence pathogen birth and death rates (pharmacodynamics) . The next area addressed is the spread of multiply drug-resistant bacteria in hospital settings . Models of the transmission dynamics of the pathogen provide a framework for assessing the relative merits of different forms of intervention, and provide criteria for control or eradication . The model is applied to the spread of vancomycin-resistant enterococci in an intensive care setting . This model framework is generalized to consider the spread of resistant organisms between hospitals . The model framework allows for heterogeneity in hospital size and highlights the importance of large hospitals in the maintenance of resistant organisms within a defined country . The spread of methicillin resistant Staphylococcus aureus (MRSA) in England and Wales provides a template for model construction and analysis . The final section addresses the emergence and spread of resistant organisms in communities of people and the dependence on the intensity of selection as measured by the volume or rate of drug use . Model output is fitted to data for Finland and Iceland and conclusions drawn concerning the key factors determining the rate of spread and decay once drug pressure is relaxed. J Hosp Infect, 1999 May, 42(1), 45 - 51 The influence of methicillin-resistant Staphylococcus aureus (MRSA) carriers in a nursery and transmission of MRSA to their households; Mitsuda T et al.; We examined two persistent MRSA-carrier nurses in a maternity hospital to elucidate the transmission of methicillin-resistant Staphylococcus aureus (MRSA) from healthcare providers to newborn infants and to the nurses' own families . Genotyping of the MRSA strains was performed by analyzing genomic DNA restriction length polymorphisms from pulsed-field gel electrophoresis (PFGE-RFLPs) . The children of these nurses were carrying genotypically identical MRSA strains as their mother . Both MRSA carrier families remained asymptomatic over a two-year follow-up period . Eradication of nasal MRSA carriage from the two nurses resulted in declining MRSA carriage rates among infants in the nursery . Healthcare providers may become transient or persistent MRSA carriers whilst working in hospitals in which MRSA is endemic . They may then become a source of infection for patients as well as their own families . We recommend that healthcare providers should be examined for MRSA if an MRSA epidemic occurs in a hospital . The families of any such carriers should also be examined for MRSA. J Chromatogr B Biomed Sci Appl, 1999 Apr 30, 727(1-2), 219 - 25 Simple and rapid analytical method for carbapenems using capillary zone electrophoresis; Taniguchi S et al.; A simple and rapid analytical method for carbapenems using high-performance capillary electrophoresis is described . All therapeutic carbapenem injections in Japan (imipenem, panipenem and meropenem) and four other beta-lactams (piperacillin, cefotiam, cefotaxime, latamoxef) were separated and determined with good repeatability in about 10 min using simple free zone capillary electrophoresis . The electrophoresis buffer was 100 mM phosphate buffer of pH 8.0, and a fused-silica capillary of 25 microm I.D . and 47 cm length was adopted . The present method was successfully applied to monitor the degradation of carbapenems under various conditions (at various temperatures or in coexistence with other drugs prescribed in the case of methicillin-resistant Staphylococcus aureus). J Vasc Surg, 1999 Jun, 29(6), 1090 - 6 Bacterial resistance of refrigerated and cryopreserved aortic allografts in an experimental virulent infection model; Litzler PY et al.; PURPOSE: The bacterial resistance of refrigerated and cryopreserved aortic allografts in a highly virulent infection in a dog model was studied . METHODS: The infrarenal aorta of 12 dogs was replaced with either a cryopreserved aortic allograft (group I, n = 6) or a refrigerated aortic allograft (group II, n = 6) in infected sites . Allografts were harvested from dogs and stored for 1 week, either by cryopreservation (-140 degrees C) or refrigerated method (4 degrees C), in a preservation medium . At the time of implantation, induction of infection was achieved with an infected piece of knitted Dacron placed just beneath the allograft . The Dacron was contaminated in vitro by soaking it in a solution with Staphylococcus aureus PR209 . All 12 dogs received no adjunct antibiotic or antithrombotic therapy . Four weeks after implantation, the animals were killed to recover the grafts for bacteriological and histological analyses . Bacterial results were expressed as colony-forming units (CFU)/cm2 of graft material . RESULTS: In group I, only one allograft grew bacteria at 2 . 16 x 10(6 )CFU/cm2, with a blood culture positive for S aureus . In group II, one dog died at 3 weeks from a false septic aneurysm rupture, all the allografts were infected (P <.05) with a mean bacterial count of 9.41 +/- 6.8 x 10(4) CFU/cm2, and three blood cultures were positive for S aureus . The patency of the grafts was analyzed at the time of recovery . Three laminar thrombi without occlusion were present in group I; none were present in group II . A better preserved endothelium in group I was revealed by means of histologic analysis staining with factor VIII antibody before implantation . After 4 weeks of implantation in the infected site, infected allografts presented polynuclear infiltrates in the media with a high degree of inflammatory reaction, and endothelial recovery was more significant in group I, with numerous young plump cells . CONCLUSION: This study demonstrates that cryopreserved allografts implanted in infected sites in a dog model can produce greater bacterial resistance. Proc Natl Acad Sci U S A, 1999 Jun 8, 96(12), 7005 - 10 Unexpected abundance of self-splicing introns in the genome of bacteriophage Twort: introns in multiple genes, a single gene with three introns, and exon skipping by group I ribozymes; Landthaler M et al.; Analysis of RNA that can be labeled with GTP indicates the existence of group I introns in genes of at least three transcriptional classes in the genome of Staphylococcus aureus bacteriophage Twort . A single ORF of 142 amino acids (Orf142) is interrupted by three self-splicing group I introns, providing the first example of a phage gene with multiple intron insertions . Twort Orf142 is encoded in a message that is abundant 15-20 min after infection and is highly similar to a late gene product (Orf8) of the morphologically related Listeria phage A511 . The introns in orf142 are spliced in vivo and contain all the conserved features of primary sequence and secondary structure of group I introns in subgroup IA2, which includes the introns in Escherichia coli phage T4 and the Bacillus phages beta22 and SPO1 . Introns I2 and I3 in orf142 are highly similar, and their intron insertion sites are closely spaced . The presence of transcripts with a skipped exon between these introns indicates that they may fold into a single active ribozyme resulting in alternative splicing . Alternatively, the cleaved 5' exon preceding I2 may undergo trans splicing to the 3' exon that follows I3 . Regardless of the detailed mechanism, these results demonstrate a new means whereby a single gene can give rise to multiple messenger RNAs. Biochem J, 1999 Jun 15, 340 ( Pt 3), 657 - 69 Protein modification during biological aging: selective tyrosine nitration of the SERCA2a isoform of the sarcoplasmic reticulum Ca2+-ATPase in skeletal muscle; Viner RI et al.; The accumulation of covalently modified proteins is an important hallmark of biological aging, but relatively few studies have addressed the detailed molecular-chemical changes and processes responsible for the modification of specific protein targets . Recently, Narayanan et al . {Narayanan, Jones, Xu and Yu (1996) Am . J . Physiol . 271, C1032-C1040} reported that the effects of aging on skeletal-muscle function are muscle-specific, with a significant age-dependent change in ATP-supported Ca2+-uptake activity for slow-twitch but not for fast-twitch muscle . Here we have characterized in detail the age-dependent functional and chemical modifications of the rat skeletal-muscle sarcoplasmic-reticulum (SR) Ca2+-ATPase isoforms SERCA1 and SERCA2a from fast-twitch and slow-twitch muscle respectively . We find a significant age-dependent loss in the Ca2+-ATPase activity (26% relative to Ca2+-ATPase content) and Ca2+-uptake rate specifically in SR isolated from predominantly slow-twitch, but not from fast-twitch, muscles . Western immunoblotting and amino acid analysis demonstrate that, selectively, the SERCA2a isoform progressively accumulates a significant amount of nitrotyrosine with age (approximately 3.5+/-0 . 7 mol/mol of SR Ca2+-ATPase) . Both Ca2+-ATPase isoforms suffer an age-dependent loss of reduced cysteine which is, however, functionally insignificant . In vitro, the incubation of fast- and slow-twitch muscle SR with peroxynitrite (ONOO-) (but not NO/O2) results in the selective nitration only of the SERCA2a, suggesting that ONOO- may be the source of the nitrating agent in vivo . A correlation of the SR Ca2+-ATPase activity and covalent protein modifications in vitro and in vivo suggests that tyrosine nitration may affect the Ca2+-ATPase activity . By means of partial and complete proteolytic digestion of purified SERCA2a with trypsin or Staphylococcus aureus V8 protease, followed by Western-blot, amino acid and HPLC-electrospray-MS (ESI-MS) analysis, we localized a large part of the age-dependent tyrosine nitration to the sequence Tyr294-Tyr295 in the M4-M8 transmembrane domain of the SERCA2a, close to sites essential for Ca2+ translocation. J Med Microbiol, 1999 Jun, 48(6), 515 - 21 Occurrence of methicillin-resistant and -susceptible Staphylococcus aureus within a single colony contributing to MRSA mis-identification; Falcao MH et al.; Many methods have been described for the detection of methicillin-resistant Staphylococcus aureus (MRSA), but the homogeneous or heterogeneous expression of methicillin resistance affects the reliability of those methods . This study demonstrates that close association between methicillin-susceptible S . aureus (MSSA) and MRSA strains in the host colonisation site can present additional problems for the detection of MRSA in clinical laboratories, which may contribute to failure in the control of MRSA infection in hospital . Worse, this association may also account for the emergence of MRSA during antibiotic therapy. J Immunol, 1999 Jun 15, 162(12), 7402 - 8 Protection by group II phospholipase A2 against Staphylococcus aureus; Laine VJ et al.; Group II phospholipase A2 (PLA2) is an enzyme that has marked antibacterial properties in vitro . To define the role of group II PLA2 in the defense against Staphylococcus aureus, we studied host responses in transgenic mice expressing human group II PLA2 and group II PLA2-deficient C57BL/6J mice in experimental S . aureus infection . After the administration of S . aureus, the transgenic mice showed increased expression of group II PLA2 mRNA in the liver and increased concentration of group II PLA2 in serum, whereas the PLA2-deficient mice completely lacked the PLA2 response . Expression of human group II PLA2 resulted in reduced mortality and improved the resistance of the mice by killing the bacteria as indicated by low numbers of live bacteria in their tissues . Human group II PLA2 was responsible for the bactericidal activity of transgenic mouse serum . These results suggest a possible role for group II PLA2 in the innate immunity against S . aureus infection. Semin Thromb Hemost, 1999, 25(2), 217 - 21 Thrombotic microangiopathy manifesting as thrombotic thrombocytopenic purpura/hemolytic uremic syndrome in the cancer patient; Gordon LI et al.; The complication of thrombotic thrombocytopenic purpura or hemolytic uremic syndrome (TTP/HUS) can occur in cancer patients . It is characterized by a microangiopathic hemolytic anemia, severe thrombocytopenia, and renal failure . Pulmonary manifestations, especially pulmonary edema, are a common observation . Neurologic changes are also frequently seen . The etiology is unknown at this time . It has been observed in many different types of cancer and is most commonly seen in gastric adenocarcinoma followed by carcinoma of the breast, colon, and small cell lung carcinoma . The hemolysis can be massive and is due to red cell fragmentation, as schistocytes are present in all the cases . Though immune complexes are present in the plasma, the antiglobulin (Coomb's) test is negative . Chemotherapeutic agents, especially mitomycin C, have been implicated as causative factors . There is a correlation of this complication with the cumulative dose . However, chemotherapy cannot account for all the cases as the syndrome can occur in untreated patients . It can be differentiated from disseminated intravascular coagulation by the absence of a coagulopathy . Management should consist of plasma exchange, use of a Staphylococcus aureus column (Prosorba), and control of hypertension . Because of the susceptibility to pulmonary edema, blood volume overloading should be avoided. Kansenshogaku Zasshi, 1999 Apr, 73(4), 328 - 35 {Soluble proteins from Staphylococcus aureus can change expression of CD11b and CD62L, but not H2O2 production by human blood granulocytes}; Onogawa T et al.; We examined the production of CD11b, CD62L and H2O2 by human peripheral blood granulocytes after treatment with soluble proteins prepared from five different pressure-disrupted strains of Staphylococcus aureus (SaSP) by flow cytometory . Peripheral blood was treated with final SaSP concentrations of 0.05, 0.5 and 5.0 micrograms for 20 min at 37 degrees C . The ratio of CD11b positive granulocytes did not increase at concentrations from 0.05 to 5.0 micrograms, but fluorescence intensity showed about two and three-fold increase, respectively, at concentrations of 0.5 and 5.0 micrograms, in comparison with that of control cells . The ratio CD62L positive cells decreased as follows: 0.5 microgram, 53.8% and 5.0 micrograms, 19.0%, respectively, whereas the control value was 79.8% . Fluorescence intensity also decreased as follows: 0.5 microgram, 10.4 and 5.0 micrograms, 9.2, respectively, whereas the control value was 46.8 . Slight induction of H2O2 was found at 5.0 micrograms concentration only . In addition, SaSP treatment granulocytes that stimulated with PMA (1 ng) increased H2O2 production . Thus, SaSP has no beneficial effect against H2O2 production by granulocytes . All of the SaSP preparations indicated similar results for the production of CD11b, CD62L and H2O2 by granulocytes . SaSP effects activation of granulocytes, and the activation may occur independently of protein kinase C. Epidemiol Infect, 1999 Apr, 122(2), 329 - 36 Coagulase gene polymorphism of Staphylococcus aureus isolates from dairy cattle in different geographical areas; Su C et al.; The objectives of this study were to investigate the coagulase gene polymorphism of Staphylococcus aureus isolates obtained from bovine mastitic milk and to determine the resistance of predominant and rare coagulase genotypes to bovine blood neutrophil bactericidal activities . A total of 453 isolates were collected from four countries: the Czech Republic, France, Korea and the United States . The isolates were subtyped into 40 types by restriction fragment length polymorphism (RFLP) of the coagulase gene . Twenty-three strains from predominant and rare genotypes were evaluated for their ability to resist neutrophil bactericidal activities . There were significant (P < 0.01) differences in the average percent neutrophil killing of the predominant (16.7%) and rare (39.7%) genotypes when bacteria were opsonized with antiserum . The results indicate that the profiles of coagulase genotype differ among geographic locations, and only a few genotypes prevail in each location . In addition, the predominant genotypes were more resistant to neutrophil bactericidal activities than rare genotypes. Epidemiol Infect, 1999 Apr, 122(2), 241 - 9 Analysis of genomic diversity within the Xr-region of the protein A gene in clinical isolates of Staphylococcus aureus; Kobayashi N et al.; Protein A of Staphylococcus aureus contains a polymorphic Xr-region characterized by a tandem repeat of eight amino acid units . In this study, the diversity of genes encoding the repeat regions and their relatedness among S . aureus strains was analyzed . Ten different protein-A types characterized by repeat numbers 4-13 were identified in a total of 293 clinical isolates . The protein-A type with 10 repeat units (10 repeats) in the Xr-region was most frequently detected in methicillin-resistant S . aureus, whereas the majority of methicillin-susceptible strains were distributed almost evenly into protein-A types with 7-11 repeats . Strains that belonged to a single coagulase type were classified into multiple protein-A types, e.g . strains with the common coagulase types II and VII were differentiated into 7 and 8 protein-A types, respectively . Nucleotide sequence analysis of the Xr-region of 42 representative strains revealed the presence of 37 different genotypes (spa types), which were constituted by a combination of several of 24 different repeat unit genotypes . Based on the similarity in arrangement of repeat unit genotypes, 34 strains with different repeat numbers were classified into 5 genetic clusters (C1-C5) . The clusters C1, C2 and C3 consisted exclusively of strains with identical coagulase types II, III, and IV, respectively . These findings suggested that the protein-A gene of S . aureus has evolved from a common ancestral clone in individual clusters independently. Epidemiol Infect, 1999 Apr, 122(2), 227 - 33 Phages for methicillin-resistant Staphylococcus aureus: an international trial; Richardson JF et al.; An internationally agreed and validated set of phages is used worldwide for the typing of strains of Staphylococcus aureus of human origin . However, because of the sometimes reduced susceptibility of methicillin-resistant strains (MRSA) to these phages, some of the national typing centres use locally isolated and characterized sets of experimental phages . In this trial, 42 such phages were distributed to 6 centres and tested against 744 isolates of MRSA with the intention of defining a phage set to augment the international set . The use of these experimental phages increased the percentage typability from 75% with the international set to 93% and the number of identifiable lytic patterns from 192 to 424 . A subset of 10 experimental phages was selected . When this subset was compared with the experimental panel, the typability rate was 91% and 370 distinct patterns were obtained . This subset of phages has been distributed for international trial. Unfallchirurg, 1999 Apr, 102(4), 324 - 8 {Nosocomial infections with methicillin-resistant Staphylococcus aureus (MRSA) and epidermidis (MRSE) strains . Their importance, prophylaxis and therapy in orthopedic surgery}; Konig DP et al.; MRSA/MRSE infections are a major problem in hospitals and although in orthopaedic units the incidence is low awareness of this problem is necessary . Once a MRSA strain has been isolated the strict use of the hygiene precautions has to be applied to avoid epidemic spread of the strain . The patient has to be isolated . The staff has to use gloves and gowns whilst treating the patient . A antimicrobiel hand wash solution has to be used after taking off the gloves and before leaving the isolation room . Patient and staff have to be informed about the pathogenicity and the way of infection spread so that infection precaution rules are fulfilled . Antibiotics should only be used in clinically well defined cases and the overall use of antibiotics should be reduced to lower the incidence of MRSA/E isolates . The problems of an MRSA case and its successful treatment are demonstrated. Diagn Microbiol Infect Dis, 1999 Jun, 34(2), 77 - 81 Detection of ileS-2 gene encoding mupirocin resistance in methicillin-resistant Staphylococcus aureus by multiplex PCR; Nunes EL et al.; The presence of the ileS-2 gene, responsible for mupirocin resistance, in clinical isolates of methicillin-resistant Staphylococcus aureus was determined by multiplex polymerase chain reaction . Three pairs of primers were used, which yielded specific fragments of femA (encoding a unique feature of S . aureus), mecA (encoding resistance to methicillin) and ileS-2 genes . The multiplex polymerase chain reaction system is an easy and time-saving technique that, together with a rapid method for DNA extraction by boiling, may be incorporated as a routine analysis in clinical diagnostic laboratories. Pediatr Infect Dis J, 1999 May, 18(5), 410 - 4 Methicillin-resistant and borderline methicillin-resistant asymptomatic Staphylococcus aureus colonization in children without identifiable risk factors; Suggs AH et al.; BACKGROUND: The recent evolution in the epidemiology of methicillin-resistant asymptomatic Staphylococcus aureus (MRSA) infections in children, whereby children without traditional risk factors for MRSA have been hospitalized in increasing numbers, prompted us to establish whether a parallel increase in "asymptomatic" MRSA colonization had occurred . METHODS: We cultured the nares and perineum of 500 children attending our Pediatric Emergency Department . RESULTS: One hundred thirty-two (26.4%) of these children were colonized with S . aureus . Eleven (8.3%) of the S . aureus isolates were MRSA; 4 (36.4%) of the 11 subjects colonized with MRSA had no risk factors . Seven (5.3%) of the 132 S . aureus isolates were borderline methicillin-resistant S . aureus (BRSA); 5 (71.4%) of the 7 subjects colonized with BRSA had no MRSA risk factors . CONCLUSIONS: These findings indicate that MRSA and BRSA isolates are circulating in the community and that MRSA isolates are no longer confined to children with frequent contact with a health care environment. Circulation, 1999 Jun 1, 99(21), 2791 - 7 Acetylsalicylic acid reduces vegetation bacterial density, hematogenous bacterial dissemination, and frequency of embolic events in experimental Staphylococcus aureus endocarditis through antiplatelet and antibacterial effects; Kupferwasser LI et al.; BACKGROUND: Platelets are integral to cardiac vegetations that evolve in infectious endocarditis . It has been postulated that the antiplatelet aggregation effect of aspirin (ASA) might diminish vegetation evolution and embolic rates . METHODS AND RESULTS: Rabbits with Staphylococcus aureus endocarditis were given either no ASA (controls) or ASA at 4, 8, or 12 mg . kg-1 . d-1 IV for 3 days beginning 1 day after infection . Vegetation weights and serial echocardiographic vegetation size, vegetation and kidney bacterial densities, and extent of renal embolization were evaluated . In addition, the effect of ASA on early S aureus adherence to sterile vegetations was assessed . In vitro, bacterial adherence to platelets, fibrin matrices, or fibrin-platelet matrices was quantified with either platelets exposed to ASA or S aureus preexposed to salicylic acid (SAL) . ASA at 8 mg . kg-1 . d-1 (but not at 4 or 12 mg . kg-1 . d-1) was associated with substantial decreases in vegetation weight (P<0.05), echocardiographic vegetation growth (P<0.001), vegetation (P<0.05) and renal bacterial densities and renal embolic lesions (P<0.05) versus controls . Diminished aggregation resulted when platelets were preexposed to ASA or when S aureus was preexposed to SAL (P<0.05) . S aureus adherence to sterile vegetations (P<0.05) or to platelets in suspension (P<0.05), fibrin matrices (P<0.05), or fibrin-platelet matrices (P<0.05) was significantly reduced when bacteria were preexposed to SAL . CONCLUSIONS: ASA reduces several principal indicators of severity and metastatic events in experimental S aureus endocarditis . These benefits involve ASA effects on both the platelet and the microbe. Biochemistry, 1999 May 18, 38(20), 6689 - 98 Structure of the agonist-binding sites of the Torpedo nicotinic acetylcholine receptor: affinity-labeling and mutational analyses identify gamma Tyr-111/delta Arg-113 as antagonist affinity determinants; Chiara DC et al.; Photoaffinity labeling of the Torpedo nicotinic acetylcholine receptor (nAChR) with {3H}d-tubocurarine (dTC) has identified a residue within the gamma-subunit which, along with the analogous residue in delta-subunit, confers selectivity in binding affinities between the two agonist sites for dTC and alpha-conotoxin (alpha Ctx) MI . nAChR gamma-subunit, isolated from nAChR-rich membranes photolabeled with {3H}dTC, was digested with Staphylococcus aureus V8 protease, and a 3H-labeled fragment was purified by reversed-phase high-performance liquid chromatography . Amino-terminal sequence analysis of this fragment identified 3H incorporation in gamma Tyr-111 and gamma Tyr-117 at about 5% and 1% of the efficiency of {3H}dTC photoincorporation at gamma Trp-55, the primary site of {3H}dTC photoincorporation within gamma-subunit {Chiara, D . C., and Cohen, J . B . (1997) J . Biol . Chem 272, 32940-32950} . The Torpedo nAChR delta-subunit residue corresponding to gamma Tyr-111 (delta Arg-113) contains a positive charge which could confer the lower binding affinity seen for some competitive antagonists at the alpha-delta agonist site . To test this hypothesis, we examined by voltage-clamp analysis and/or by {125I}alpha-bungarotoxin competition binding assays the interactions of acetylcholine (ACh), dTC, and alpha Ctx MI with nAChRs containing gamma Y111R or delta R113Y mutant subunits expressed in Xenopus oocytes . While these mutations affected neither ACh equilibrium binding affinity nor the concentration dependence of channel activation, the gamma Y111R mutation decreased by 10-fold dTC affinity and inhibition potency . Additionally, each mutation conferred a 1000-fold change in the equilibrium binding of alpha Ctx MI, with delta R113Y enhancing and gamma Y111R weakening affinity . Comparison of these results with previous results for mouse nAChR reveals that, while the same regions of gamma- (or delta-) subunit primary structure contribute to the agonist-binding sites, the particular amino acids that serve as antagonist affinity determinants are species-dependent. Biochemistry, 1999 May 18, 38(20), 6537 - 46 Penicillin-binding protein 2a from methicillin-resistant Staphylococcus aureus: kinetic characterization of its interactions with beta-lactams using electrospray mass spectrometry; Lu WP et al.; Penicillin-binding protein 2a (PBP2a) is the primary beta-lactam resistance determinant of methicillin-resistant Staphylococcus aureus (MRSA) . MecA, the gene coding for PBP2a, was cloned with the membrane-anchoring region at the N-terminus deleted . The truncated protein (PBP2a) was overexpressed in Escherichia coli mostly in the soluble form accounting for approximately 25% of soluble cell protein and was purified to homogeneity . The purified protein was shown to covalently bind beta-lactams in an 1:1 ratio as determined by electrospray mass spectrometry . A novel method based on HPLC-elctrospray mass spectrometry has been developed to quantitatively determine the formation of the covalent adducts or acyl-PBP2a complexes . By using this method, combined with kinetic techniques including quench flow, we have extensively characterized the interactions between PBP2a and three beta-lactams and determined related kinetic parameters for the first time . The apparent first-order rate constants (ka) of PBP2a acylation by benzylpenicillin showed a hyperbolic dependence on the concentration of benzylpenicillin . This is consistent with the mechanism that the binding of the penicillin to PBP2a consists of reversible formation of a Michaelis complex followed by formation of the penicilloyl-PBP2a adduct, and allowed the determination of the individual kinetic parameters for these two steps, the dissociation constant Kd of 13.3 mM and the first-order rate constant k2 of 0.22 s-1 . From these values, the second-order rate constant k2/Kd, the value reflecting the overall binding efficiency of a beta-lactam, of 16.5 M-1 s-1 was obtained . The fairly high Kd value indicates that benzylpenicillin fits rather poorly into the protein active site . Similar studies on the interaction between PBP2a and methicillin revealed k2 of 0.0083 s-1 and Kd of 16.9 mM, resulting in an even smaller k2/Kd value of 0.49 M-1 s-1 . The rate constants k3 for deacylation of the acyl-PBP2a complexes, the third step in the interactions, were measured to be <1.5 x 10(-)5 s-1 . These results indicate that the resistance of PBP2a to penicillin inactivation is mainly due to the extremely low penicillin acylating rate in addition to the low association affinity, but not to a fast rate of deacylation . Acylation of PBP2a by a high-affinity cephalosporin, Compound 1, also followed a saturation curve of ka versus the compound concentration, from which k2 = 0.39 s-1, Kd = 0.22 mM, and k2/Kd = 1750 M-1 s-1 were obtained . The 100-fold increase in the k2/Kd value as compared with that of benzylpenicillin is mostly attributable to the decreased (60-fold) Kd, indicating that the cephalosporin fits much better to the binding pocket of the protein. Age Ageing, 1999 Mar, 28(2), 229 - 32 Nasal colonization by Staphylococcus aureus in active, independent, community seniors; Lee YL et al.; OBJECTIVE: to evaluate the prevalence of nasal colonization with Staphylococcus aureus (SA) in active, independent community seniors and old people in a nursing home . DESIGN: cross-sectional brief questionnaire and screening culture of anterior nares specimens from 165 elders at a community centre and cross-sectional data from a recent survey in a nursing home . RESULTS: the prevalence of SA colonization in community seniors (27%) was similar to that in the nursing home (29%) . The proportion of SA isolates that were methicillin-resistant was much lower in the community seniors (2.3%) than in the nursing-home residents (31%) . There was less antibiotic resistance in those living at home . CONCLUSION: in community seniors the prevalence of SA colonization was similar to that in nursing-home residents, but the prevalence of methicillin-resistant SA was lower . Susceptibility patterns of antibiotics tested against the SA showed less resistance than isolates from nursing-home patients. J Antimicrob Chemother, 1999 Apr, 43(4), 593 - 6 Concentration and bactericidal activity of fusidic acid and cloxacillin in serum and synovial fluid; Somekh E et al.; Fusidic acid and cloxacillin were studied in patients who underwent joint aspiration for noninfectious disorders . Nine patients were given oral 500 mg fusidic acid tid for 72 h, the last dose being given 4, 8 or 12 h before the joint aspiration . Cloxacillin was administered in a single 2 g iv dose to 9 patients, 0.5, 4 or 8 h before the aspiration . Bactericidal activity was determined against five isolates each of methicillin-susceptible and methicillin-resistant Staphylococcus aureus . Satisfactory activity (> or = 1:3) was detected in the serum in patients who received fusidic acid, while in the synovial fluids titres reflected borderline effectiveness (c . 1:2) . Despite drug concentrations and excellent MICs, fusidic acid demonstrated markedly lower inhibitory and bactericidal activity against S . aureus than did cloxacillin. J Antimicrob Chemother, 1999 Apr, 43(4), 589 - 91 Effect of teicoplanin on isolation of Staphylococcus aureus from blood culture media; Chern IF et al.; Intraoperative bacteraemia has been used as an indicator of the efficacy of prophylactic antibiotics . Two clinical isolates of Staphylococcus aureus in nutrient broth, with or without human serum, were exposed to teicoplanin (50 mg/L) and, either immediately or after 30 min, inoculated into blood culture bottles . Bottles with and without resin were used and the experiment was repeated five times with one strain . In the absence of teicoplanin, an inoculum of 10 cfu/mL produced growth in both resin and non-resin bottles . In the presence of teicoplanin, an inoculum of at least 10(5) cfu/mL was required in non-resin bottles to obtain growth, but this was reduced to 10(2)-10(3) cfu/mL for resin bottles . Intraoperative blood cultures overestimate the efficacy of bacterial killing by prophylactic antibiotics during surgery. J Antimicrob Chemother, 1999 Apr, 43(4), 467 - 75 Evaluation of a new 3-h hybridization method for detecting the mecA gene in Staphylococcus aureus and comparison with existing genotypic and phenotypic susceptibility testing methods; Skov RL et al.; A new 3-h hybridization assay for detection of the staphylococcal mecA gene and the Staphylococcus aureus nuclease gene was evaluated by comparing the assay with existing genotypic and phenotypic methods . A total of 275 S . aureus strains were tested, including 257 epidemiologically unrelated strains (135 mecA-positive and 122 mecA-negative; collection I), and 18 strains with known borderline resistance to methicillin (collection II) . Complete agreement was obtained for both collections when comparing the new assay with genotypic methods . We further evaluated a range of phenotypic susceptibility methods recommended in Europe and/or USA using the presence of the mecA gene as the defining standard . For collection I a high degree of agreement was found for both Etests (256 strains) and the oxacillin screen plate test (255 strains); the degree of agreement was lower for agar dilution methicillin (250 strains) and oxacillin 1 microg discs (239 strains) . For the borderline strains a high degree of agreement was only obtained by the oxacillin screen plate test (17 of 18 strains) . The other tests were less accurate, in the following order: agar dilution methicillin, Etest methicillin, Etest oxacillin and oxacillin discs with disagreement for four, five, nine and 13 strains, respectively . In conclusion, the new hybridization assay is a rapid and exact method for detecting the mecA gene and the S . aureus nuclease gene . This study confirms that phenotypic tests for methicillin resistance in S . aureus strains creates both false-susceptible and false-resistant results, especially for borderline resistant strains. Infect Control Hosp Epidemiol, 1999 May, 20(5), 362 - 6 Issues in the management of resistant bacteria in long-term-care facilities; Bradley SF; The prevalence of antibiotic-resistant bacteria in the long-term-care setting and the risk to nursing home residents is still unknown . Few studies have been done in community-based nursing homes, and most have focused on colonization rather than infection rates . Concerns about methicillin-resistant Staphylococcus aureus and vancomycin-resistant enterococci have been expressed most often, while relatively scant attention has been paid to the problem of antibiotic resistance in gram-negative bacilli . Antibiotic resistance precautions need to be developed for nursing homes that are simple, effective, inexpensive, and recognize the unique rehabilitative and long-term custodial missions of chronic-care facilities. Infect Control Hosp Epidemiol, 1999 May, 20(5), 353 - 5 Outbreak of methicillin-resistant Staphylococcus aureus in a German tertiary-care hospital; Ruchel R et al.; A biphasic outbreak of methicillin-resistant Staphylococcus aureus in intensive-care units of a German tertiary-care hospital afflicted 89 patients within 4 years . The spread of the outbreak most likely was facilitated by the contamination of mobile radiograph equipment . The outbreak was controlled by measures of hospital hygiene. Infect Control Hosp Epidemiol, 1999 May, 20(5), 351 - 3 Bacitracin versus mupirocin for Staphylococcus aureus nasal colonization; Soto NE et al.; We performed a randomized prospective study of 5-day treatment with topical mupirocin or bacitracin for the elimination of Staphylococcus aureus nasal colonization in healthcare workers (HCWs) . Nasal cultures were obtained from 141 HCWs, 37 (26%) of whom showed S . aureus . After 72 to 96 hours of treatment, the organism was eradicated in 15 (94%) of 16 by mupirocin and in 8 (44%) of 18 by bacitracin (P = .0031) . Similar efficacy was demonstrated at 30 days . Mupirocin may be more effective than bacitracin for eradication of S . aureus in healthy HCWs. Medicina (B Aires), 1999, 59(1), 43 - 8 {Risk factors for nosocomial bacterial infection in children: a case-control study}; Paganini HR et al.; With the objective to identify independent risk factors associated with the development of nosocomial bacteremia, we have performed a prospective, exploratory, case-control study . All non-neutropenic children with nosocomial bacteremia admitted during a seven-month period were eligible . All children non-neutropenic without nosocomial bacteremia were eligible as controls . The incidence of bacteremia in the study population was 11.3/1000 admissions . Ninety one cases and ninety nine controls were analyzed . In 46% of patients clinical foci were detected . The catheter-related infection was the most frequently founded . Staphylococcus spp coagulase negative, Staphylococcus aureus and Klebsiella pneumoniae were the microorganisms more frequently isolated . Multivariate analysis identified five risk factors independently associated with nosocomial bacteremia: admission outside of Intensive Care Units (ICU) (OR: 8.14, 2.60-25.5), previous antibiotic treatment (OR: 5.02, 2.18-11.5), invasive procedures (OR: 5.35, 1.70-16.8), without surgery (OR: 2.99, 1.37-6.52) and the presence of central venous lines (OR: 5.35, 2.13-12.4) . Our data give strong support for the value of testing strict guidelines for limiting vascular catheter and antibiotic use, and limiting the invasive procedures. Antimicrob Agents Chemother, 1999 Jun, 43(6), 1449 - 58 Cloning and nucleotide sequence determination of the entire mec DNA of pre-methicillin-resistant Staphylococcus aureus N315; Ito T et al.; In methicillin-resistant Staphylococcus aureus, the methicillin resistance gene mecA is localized within a large chromosomal region which is absent in the methicillin-susceptible S . aureus chromosome . The region, designated mec DNA, is speculated to have originated from the genome of another bacterial species and become integrated into the chromosome of the S . aureus cell in the past . We report here cloning and determination of the structure of the entire mec DNA sequence from a Japanese S . aureus strain, N315 . The mec DNA was found to be 51,669 bp long, including terminal inverted repeats of 27 bp and a characteristic pair of direct repeat sequences of 15 bp each: one is situated in the right extremity of mec DNA, and the other is situated outside the mec DNA and abuts the left boundary of mec DNA . The integration site of mec DNA was found to be located in an open reading frame (ORF) of unknown function, designated orfX . Clusters of antibiotic resistance genes were noted in mec DNA carried by transposon Tn554 and an integrated copy of plasmid pUB110 . Both the transposon and plasmid were integrated in the proximity of the mecA gene, the latter being flanked by a pair of insertion sequence IS431 elements . Many ORFs other than those encoding antibiotic resistance were considered nonfunctional because of the acquired mutations or partial deletions found in the ORFs . Two ORFs potentially encoding novel site-specific recombinases were found in mec DNA . However, there was no ORF that might encode mec DNA-specific transposase or integrase proteins, indicating that the mec DNA is not a transposon or a bacteriophage in nature. Antimicrob Agents Chemother, 1999 Jun, 43(6), 1429 - 34 Characterization of novel antimicrobial peptoids; Goodson B et al.; Peptoids differ from peptides in that peptoids are composed of N-substituted rather than alpha-carbon-substituted glycine units . In this paper we report the in vitro and in vivo antibacterial activities of several antibacterial peptoids discovered by screening combinatorial chemistry libraries for bacterial growth inhibition . In vitro, the peptoid CHIR29498 and some of its analogues were active in the range of 3 to 12 microg/ml against a panel of gram-positive and gram-negative bacteria which included isolates which were resistant to known antibiotics . Peptoid antimicrobial activity against Staphylococcus aureus was rapid, bactericidal, and independent of protein synthesis . beta-Galactosidase and propidium iodide leakage assays indicated that the membrane is the most likely target of activity . Positional isomers of an active peptoid were also active, consistent with a mode of action, such as membrane disruption, that does not require a specific fit between the molecule and its target . In vivo, CHIR29498 protected S . aureus-infected mice in a simple infection model. Antimicrob Agents Chemother, 1999 Jun, 43(6), 1324 - 8 Molecular investigation of the postantibiotic effects of clarithromycin and erythromycin on Staphylococcus aureus cells; Champney WS et al.; The kinetics of recovery after inhibition of growth by erythromycin and clarithromycin were examined in Staphylococcus aureus cells . After inhibition for one mass doubling by 0.5 microg of the antibiotics/ml, a postantibiotic effect (PAE) of 3 and 4 h duration was observed for the two drugs before growth resumed . Cell viability was reduced by 25% with erythromycin and 45% with clarithromycin compared with control cells . Erythromycin and clarithromycin treatment reduced the number of 50S ribosomal subunits to 24 and 13% of the number found in untreated cells . 30S subunit formation was not affected . Ninety minutes was required for resynthesis to give the control level of 50S particles . Protein synthesis rates were diminished for up to 4 h after the removal of the macrolides . This continuing inhibition of translation was the result of prolonged binding of the antibiotics to the 50S subunit as measured by 14C-erythromycin binding to ribosomes in treated cells . The limiting factors in recovery from macrolide inhibition in these cells, reflected as a PAE, are the time required for the synthesis of new 50S subunits and the slow loss of the antibiotics from ribosomes in inhibited cells. Science, 1999 May 28, 284(5419), 1523 - 7 Broadly protective vaccine for Staphylococcus aureus based on an in vivo-expressed antigen; McKenney D et al.; Vaccines based on preferential expression of bacterial antigens during human infection have not been described . Staphylococcus aureus synthesized poly-N-succinyl beta-1-6 glucosamine (PNSG) as a surface polysaccharide during human and animal infection, but few strains expressed PNSG in vitro . All S . aureus strains examined carried genes for PNSG synthesis . Immunization protected mice against kidney infections and death from strains that produced little PNSG in vitro . Nonimmune infected animals made antibody to PNSG, but serial in vitro cultures of kidney isolates yielded mostly cells that did not produce PNSG . PNSG is a candidate for use in a vaccine to protect against S . aureus infection. Am J Med, 1999 May 3, 106(5A), 11S - 18S; discussion 48S-52S Control of methicillin-resistant Staphylococcus aureus in the hospital setting; Herwaldt LA; Methicillin-resistant Staphylococcus aureus (MRSA) is a common cause of nosocomial infections . Healthcare professionals in the United States should develop programs to prevent transmission of this organism within their institutions . Aggressive control efforts are justified for several reasons: (1) the incidence of nosocomial MRSA reflects the general effectiveness of infection control practice; (2) MRSA do not replace susceptible strains but instead increase the overall rate of nosocomial S . aureus infections; (3) MRSA infections cause substantial morbidity and mortality; (4) serious MRSA infections must be treated with vancomycin . Thus, in hospitals with high rates of MRSA, use of this antimicrobial agent increases, which in turn may increase the risk for selecting vancomycin-resistant enterococci . Hospitals have used numerous different approaches to control nosocomial spread of MRSA . Staff should choose a control method based on the prevalence of MRSA in their institution and in their referring facilities, the rate of nosocomial transmission of MRSA in their hospital, the risk factors present in their patient population, the reservoirs and modes of transmission specific to their hospital, and their resources . Any MRSA control plan must stress adherence to basic infection control measures, such as hand washing and contact isolation precautions . In addition, decolonization of patients and staff, control of antimicrobial use, surveillance cultures, and molecular typing may be helpful adjuncts. Am J Med, 1999 May 3, 106(5A), 2S - 10S; discussion 48S-52S Methicillin-resistant Staphylococcus aureus: long-term care concerns; Bradley SF; Colonization of residents of long-term care facilities with methicillin-resistant Staphylococcus aureus (MRSA) is an important healthcare concern . MRSA colonization is prevalent; in two of the most common sites of colonization, nares and wounds, colonization rates range from 8% to 53%, and 30% to 82%, respectively . With such a large number of patients harboring the organism, it is imperative that long-term care facilities are knowledgeable regarding the overall significance of MRSA, are aware of MRSA infection rates at their facilities, and have established a threshold above which outbreak precautions will be instituted . More importantly, facilities must ensure that appropriate precautions (e.g., hand washing, glove changes, gowns) are utilized to prevent transmission of MRSA to noncolonized residents . If these basic measures are taken, MRSA-colonized residents of long-term facilities should be able to be fully integrated into the everyday activities within the long-term care environment . In the event of an outbreak of MRSA infection, stricter isolation of colonized and infected residents is warranted, and such isolation should be discontinued as soon as the chain of transmission has been disrupted . Systemic antibiotics should be avoided in asymptomatic colonized patients; topical antibiotics like mupirocin should be reserved for short-term administration in outbreak situations. J Antibiot (Tokyo), 1999 Mar, 52(3), 269 - 75 Lactonamycin, a new antimicrobial antibiotic produced by Streptomyces rishiriensis MJ773-88K4 . I . Taxonomy, fermentation, isolation, physico-chemical properties and biological activities; Matsumoto N et al.; Lactonamycin (1) was isolated from a culture broth of Streptomyces rishiriensis MJ773-88K4 . Antibiotic 1 exhibited antimicrobial activities against Gram-positive bacteria including methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus (VRE). J Antibiot (Tokyo), 1999 Feb, 52(2), 127 - 33 Time and concentration dependent influence of dirithromycin on neutrophils oxidative burst; Levert H et al.; Dirithromycin is a 14-membered macrolide antibiotic, well known to yield high intragranulocytic levels after several hour exposure . We chose therefore to investigate oxidative metabolism after prolonged incubation periods with neutrophils . Neutrophil generation of reactive oxygen species, represented by superoxide anion, was assessed after fMLP or Staphylococcus aureus-induced activation of the respiratory burst . Cellular uptake of the drug was assessed concurrently, in order to attempt a correlation with time-dependent modifications of the cellular oxidative status . For 1 hour exposure time, a pro-oxidant effect was reported for lower concentrations, achievable during therapeutic administration, whereas the highest ones promoted a potent anti-oxidant effect . After prolonged incubation times, the anti-oxidant effect alone was reported, with time-dependent modifications of IC50 values . These values could be correlated with intracellular accumulation of the drug . The anti-inflammatory activity reported here for high dirithromycin concentrations, could be nevertheless clinically relevant, since dirithromycin cellular uptake extends beyond 4 hours. J Pediatr Orthop, 1999 May-Jun, 19(3), 413 - 6 Community-acquired methicillin-resistant Staphylococcus aureus: a cause of musculoskeletal sepsis in children; Gwynne-Jones DP et al.; Between August 1996 and August 1997, 130 children were admitted to our pediatric orthopaedic unit with Staphylococcus aureus musculoskeletal infection . Twenty-six of the 130 staphylococcal isolates were resistant to methicillin, an incidence of 20% . All but one of the infections, a femoral fixator-pin infection, were community-acquired . Twenty-two of the infections were superficial; however, there were four cases of deep musculoskeletal sepsis due to methicillin-resistant S . aureus . In areas where methicillin-resistant S . aureus is prevalent in the community, methicillin resistance should be considered in any overwhelming staphylococcal infection not responding to conventional antibiotics despite adequate surgical debridement. Microb Pathog, 1999 Jun, 26(6), 317 - 23 Mechanisms of Staphylococcus aureus invasion of cultured osteoblasts; Ellington JK et al.; Staphylococcus aureus is a bacterial pathogen causing approximately 80% of all cases of human osteomyelitis . This bacterium can adhere to and become internalized by osteoblasts and previous studies indicate that osteoblasts are active in the internalization process . In the current study, we examined the roles of microfilaments, microtubules and clathrin-dependent receptor-mediated endocytosis in the internalization of S . aureus by MC3T3-E1 mouse osteoblast cells . Microfilament and microtubule polymerization was inhibited with cytochalasin D and colchicine . Clathrin-coated pit formation was examined by using the transaminase inhibitor, monodanslycadaverine . The results of this study indicate that mouse osteoblasts utilize actin microfilaments, microtubules and clathrin-coated pits in the internalization of S . aureus; however, microfilaments seem to play the most significant role in the invasion process . Curr Microbiol, 1999 Jun, 38(6), 342 - 8 Superiority of 11,12 carbonate macrolide antibiotics as inhibitors of translation and 50S ribosomal subunit formation in Staphylococcus aureus cells; Champney WS et al.; Three pairs of related macrolide antibiotics, differing at the 11,12 position of the macrolactone ring, were compared for effects on growth rate, cell viability, protein synthesis, and 50S ribosomal subunit formation in Staphylococcus aureus cells . For each parameter measured, the 11,12 carbonate-derivatized compound was more inhibitory compared with the corresponding 11,12-hydroxy antibiotic . Substitution at the 3-position of the ring was also important in the relative inhibition observed . The degree of inhibition found in two different growth media was proportional to the generation time of the cells . Inhibition of both protein synthesis and 50S subunit formation by each drug correlated well with the inhibition of cell viability . The results indicate that closure of the 11,12-hydroxyl groups in macrolide antibiotics with a carbonate substitution generates a more effective antimicrobial agent. Curr Eye Res, 1999 Mar, 18(3), 177 - 85 A comparison of the early inflammatory effects of an agr-/sar- versus a wild type strain of Staphylococcus aureus in a rat model of endophthalmitis; Giese MJ et al.; PURPOSE: We examined the ability of a wild type and an isogenic mutant strain of Staphylococcus