Ten patients with bacteremia due to methicillin-resistant Staphylococcus aureus were treated with vancomycin. These patients were compared with matched controls, nine bacteremic patients with methicillin-sensitive S. aureus, and one patient with penicillin-sensitive S. aureus. Controls were treated with a penicillin. There were no significant differences in time to defervescence, metastatic infections, relapse, mortality, need for surgical drainage, or duration of therapy. Fifteen of 19 episodes of serious methicillin-resistant S. aureus infection responded to vancomycin. Severe toxic effects included tinnitus, neutropenia, rash, and possible nephrotoxicity. Tolerance (a minimal bactericidal concentration to minimal inhibitory concentration ratio of at least 32), but not a minimal bactericidal concentration of at least 32 mg/L, correlated with therapeutic failure (respectively, p = 0.04 and p = 0.11, Fisher's exact test). Bacteremic infections due to methicillin-resistant and methicillin-sensitive S. aureus cause similar morbidity and mortality. Vancomycin is effective but potentially toxic therapy for most serious infections due to methicillin-resistant S. aureus. In-vitro tests may not predict therapeutic efficacy.
We report seven cases of endocarditis due to nontoxigenic Corynebacterium diphtheriae that occurred between October 1990 and September 1991. The patients all lived in the state of New South Wales, Australia. Three patients had preexisting cardiac abnormalities, and one patient used intravenous drugs regularly. The other three patients had no known risk factors for endocarditis. Notable clinical features were the aggressive nature of the infection, the occurrence of septic arthritis in four patients, and major vascular complications in four patients, one of whom died. One patient required urgent mitral valve replacement. All of the isolates were identified as non-toxigenic C. diphtheriae var gravis. Sporadic cases of endocarditis due to C. diphtheriae have rarely been reported; septic arthritis complicating endocarditis due to this organism has not previously been described. This report highlights the importance of identifying Corynebacterium isolates from normally sterile sites at the species level.
SUMMARYAttempts were made to identify the causative organism of Lyme disease in Australia from possible tick vectors.Ticks were collected in coastal areas of New South Wales, Australia, from localities associated with putative human infections. The ticks were dissected; a portion of the gut contents was examined for spirochaetes by microscopy, the remaining portion inoculated into culture media. The detection of spirochaetes in culture was performed using microscopy, and immunochemical and molecular (PCR) techniques. Additionally, whole ticks were tested with PCR for spirochaetes.From 1990 to 1992, approximately 12000 ticks were processed for spirochaetes. No evidence ofBorrelia burgdorferior any other spirochaete was recovered from or detected in likely tick vectors. Some spirochaete–like objects detected in the cultures were shown to be artifacts, probably aggregates of bacterial flagellae.There is no definitive evidence for the existence in Australia ofB. burgdorferithe causative agent of true Lyme disease, or for any other tick–borne spirochaete that may be responsible for a local syndrome being reported as Lyme disease.
Minimal inhibitory and minimal bactericidal concentrations were determined for eighteen methicillin-resistant Staphylococcus aureus isolates, the majority also resistant to gentamicin, obtained from the blood of bacteraemic patients. Fifty per cent of organisms had a greater than four-fold difference in M.I.C. and M.B.C. for vancomycin, 83% for rifampicin, and 89% for fusidic acid. In-vitro effects of two-drug combinations of vancomycin, rifampicin, and fusidic acid demonstrated neither synergy nor antagonism when measured by a checkerboard dilution technique. The relevance of these findings to choice of therapy of serious infection due to methicillin-gentamicin resistant Staph. aureus is yet to be determined.
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