Streptococcus anginosus (milleri) group strains isolated in Poland 1996-2012 and their antibiotic resistance patterns
Katarzyna Obszańska, Izabella Kern-Zdanowicz , Aleksandra Kozińska, Katarzyna Machura, Elżbieta Stefaniuk , Waleria Hryniewicz, Izabela Sitkiewicz Pol J Microbiol 2016; 65 (1): ICID: 1197323 Article type: Original article IC™ Value: 10.00
Abstract provided by Publisher
Streptococcus anginosus, Streptococcus intermedius and Streptococcus constellatus form group of related streptococcal species namely Streptococcus Anginosus Group (SAG). The group, previously called “milleri” has been rarely described until 1980/1990 as source of infections. Nowadays SAG bacteria are often described as pathogens causing predominantly purulent infections. The number of infections is highly underestimated, as SAG strains are often classified in the microbiology laboratory as less virulent “viridans streptococci”. Epidemiological situation regarding SAG infections in Poland has been unrecognized, therefore we performed retrospective analysis of strains isolated between 1996 and 2012. Strains suspected of belonging to SAG were re-identified using automated biochemical approach (Vitek2) and MALDI-TOF MS. We performed first analysis of antibiotic resistance among SAG strains isolated in Poland using automated methods (Vitek2), disk diffusion tests and E-Tests. We also performed PCR detection of resistance determinants in antibiotic resistant strains.
Clonal structure of analyzed strains was evaluated with PFGE and MLVF methods.
All three species are difficult to distinguish using automated diagnostic methods and the same is true for automated MIC evaluation. Our analysis revealed SAG strains are rarely isolated in Poland, predominantly from purulent infections. All isolates are very diverse on the genomic level as estimated by PFGE and MLVF analyses. All analyzed strains are sensitive to penicillin, a substantial group of strains is resistant to macrolides and majority of strains are resistant to tetracycline.