ABSTRACT
Coagulase-negative staphylococci (CNS) are the major cause of nosocomial infections. Methicillin-resistant strains are particularly important because they narrow therapeutic options. Detecting methicillin resistance among CNS has been a challenge for years. The objective of this study was to determine the accuracy of an agar screening test (0.6 and 4 microg oxacillin ml(-1)), disc diffusion and the automated MicroScan system to characterize methicillin resistance among CNS. One hundred and seventy five strains were analysed: 41.1 % Staphylococcus epidermidis and 59.9 % other species; 69.1 % were mecA-positive. The results showed that the methods have optimal correlation with the detection of mecA gene for S. epidermidis, Staphylococcus hominis and Staphylococcus haemolyticus. However, accuracy of the tests is impaired when less common species are analysed. The only 100 % accurate test was agar screening with 4 microg oxacillin ml(-1).
Subject(s)
Methicillin Resistance , Microbial Sensitivity Tests/methods , Phenotype , Staphylococcus/drug effects , Anti-Bacterial Agents/pharmacology , Bacterial Proteins/metabolism , Gene Expression Regulation, Bacterial , Methicillin/pharmacology , Oxacillin/pharmacology , Sensitivity and Specificity , Species SpecificityABSTRACT
A multicenter study was carried out in order to compare the in vitro activity of sparfloxacin, to ciprofloxacin, amoxicillin/clavulanic acid, cephalexin, cefuroxine and azithromycin, against 1,125 microorganisms recently isolated from clinical specimens, most of them representative of respiratory tract infections. Sparfloxacin demonstrated potent action and was more active than the ß-lactan agents and azithromycin against most of the bacterial strains tested. Sparfloxacin was more potent (96 percent and 95 percent sensitivity, with MIC90 of 0.19µg/mL and 0.5µg/mL, respectively) than the order antimicrobial agents tested against the Enterobacteriaceae family (Escherichia coli and Klebsiella pneumoniae). It was found to be equivalent in activity to ciprofloxacin (96 percent and 91 percent sensitivity and MIC90 of o.25 and 0.75µg/mL, respectively). Sparfloxacin was also found to be very active against the most fastidious microorganisms commonly associated to respiratory tract infections such as the penicillin-susceptible and resistant Haemophilus influenzae (MIC90 0.032µg/mL) and non ß-lactamase producing Moraxella catarrhalis (MIC90 0.5µg/mL).
