title: Comparison between automated system and PCR-based method for identification and antimicrobial susceptibility profile of clinical Enterococcus spp.
abstract: Enterococci are increasingly responsible for nosocomial infections worldwide. This study was undertaken to compare the identification and susceptibility profile using an automated MicrosScan system, PCR-based assay and disk diffusion assay of Enterococcus spp. We evaluated 30 clinical isolates of Enterococcus spp. Isolates were identified by MicrosScan system and PCR-based assay. The detection of antibiotic resistance genes (vancomycin, gentamicin, tetracycline and erythromycin) was also determined by PCR. Antimicrobial susceptibilities to vancomycin (30 µg), gentamicin (120 µg), tetracycline (30 µg) and erythromycin (15 µg) were tested by the automated system and disk diffusion method, and were interpreted according to the criteria recommended in CLSI guidelines. Concerning Enterococcus identification the general agreement between data obtained by the PCR method and by the automatic system was 90.0% (27/30). For all isolates of E. faecium and E. faecalis we observed 100% agreement. Resistance frequencies were higher in E. faecium than E. faecalis. The resistance rates obtained were higher for erythromycin (86.7%), vancomycin (80.0%), tetracycline (43.35) and gentamicin (33.3%). The correlation between disk diffusion and automation revealed an agreement for the majority of the antibiotics with category agreement rates of > 80%. The PCR-based assay, the van(A) gene was detected in 100% of vancomycin resistant enterococci. This assay is simple to conduct and reliable in the identification of clinically relevant enterococci. The data obtained reinforced the need for an improvement of the automated system to identify some enterococci.
authors.affiliation: Technological Federal University of Paraná, Brazil, Technological Federal University of Paraná, Brazil.
authors.forename: Luciana
authors.initials: L
authors.lastname: Furlaneto-Maia
authors.affiliation: Department of Microbiology, State University at Londrina, Paraná, Brazil, Department of Microbiology, State University at Londrina, Paraná, Brazil.
authors.forename: Kátia Real
authors.initials: KR
authors.lastname: Rocha
authors.affiliation: Department of Clinical Analysis, State University at Maringa, Paraná, Brazil, Department of Clinical Analysis, State University at Maringa, Paraná, Brazil.
authors.forename: Vera Lúcia Dias
authors.initials: VL
authors.lastname: Siqueira
authors.affiliation: Department of Microbiology, State University at Londrina, Paraná, Brazil, Department of Microbiology, State University at Londrina, Paraná, Brazil.
authors.forename: Márcia Cristina
authors.initials: MC
authors.lastname: Furlaneto
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D052978:Disk Diffusion Antimicrobial Tests; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D016983:Enterococcus / Q000145:classification / Q000187:drug effects* / Q000235:genetics; D006801:Humans; D016133:Polymerase Chain Reaction; D019105:Random Amplified Polymorphic DNA Technique
chemical_list: D000900:Anti-Bacterial Agents