ABSTRACT
UNLABELLED: The aim of this study was to test the susceptibility of 100 strains (pneumococci and viridans streptococci) isolated from oral and respiratory tract infections and their complications, against one antibiotic of each of the following classes: quinolones, oxazolidinones and glycopeptides. MATERIAL AND METHODS: The Etest has been used in order to investigate the susceptibility of the isolates against levofloxacin, linezolid and vancomycin. RESULTS AND CONCLUSIONS: As expected, the results of the study indicated that all isolates were susceptible to linezolid and vancomycin. In contrast to the pneumococcal isolates, which were all susceptible to levofloxacin, 10% of the viridans strains showed resistance to this quinolone. When fluoroquinolones are needed as an alternative to the beta-lactam antibiotics in infections in which oral streptococci are involved, the in vitro susceptibility testing is required.
Subject(s)
Anti-Bacterial Agents/pharmacology , Anti-Infective Agents/pharmacology , Glycopeptides/pharmacology , Oxazolidinones/pharmacology , Quinolones/pharmacology , Streptococcus pneumoniae/drug effects , Viridans Streptococci/drug effects , Humans , Microbial Sensitivity Tests/methods , Respiratory Tract Infections/drug therapy , Respiratory Tract Infections/microbiology , Streptococcus pneumoniae/isolation & purification , Viridans Streptococci/isolation & purificationABSTRACT
UNLABELLED: The aim of this study was to develop a new selective medium for isolation of Streptococcus anginosus group (SAG) strains, by adding sulphamethazine and aztreonam as selective agents at Mitis-Salivarius agar (MSA), the medium commonly used for recovery of oral streptococci from oral samples. MATERIAL AND METHOD: The evaluation of Mitis-Salivarius--sulphamethazine--aztreonam agar (MSSAA) for SAG selectivity was performed by testing the growth of type strains and laboratory-stored clinical isolates of different oral streptococcal species on this medium and also by investigating the SAG recovery on MSSAA in comparison with MSA and the growth inhibition of non-SAG strains from 100 saliva and 11 pus samples (collected from healthy young subjects and from paediatric patients with upper respiratory tract infections, respectively) on MSSAA. RESULTS: The same SAG recovery rate was obtained on both MSSAA and MSA, while non-SAG strains failed to grow on the novel medium, except for enterococci. The results of the present study have indicated that MSSAA is a suitable medium for selecting SAG isolates from clinical specimens.
