title: Identification of Staphylococcus saprophyticus isolated from patients with urinary tract infection using a simple set of biochemical tests correlating with 16S-23S interspace region molecular weight patterns.
abstract: The emergence of Staphylococcus spp. not only as human pathogens, but also as reservoirs of antibiotic resistance determinants, requires the development of methods for their rapid and reliable identification in medically important samples. The aim of this study was to compare three phenotypic methods for the identification of Staphylococcus spp. isolated from patients with urinary tract infection using the PCR of the 16S-23S interspace region generating molecular weight patterns (ITR-PCR) as reference. All 57 S. saprophyticus studied were correctly identified using only the novobiocin disk. A rate of agreement of 98.0% was obtained for the simplified battery of biochemical tests in relation to ITR-PCR, whereas the Vitek I system and novobiocin disk showed 81.2% and 89.1% agreement, respectively. No other novobiocin-resistant non-S. saprophyticus strain was identified. Thus, the novobiocin disk is a feasible alternative for the identification of S. saprophyticus in urine samples in laboratories with limited resources. ITR-PCR and the simplified battery of biochemical tests were more reliable than the commercial systems currently available. This study confirms that automated systems are still unable to correctly differentiate CoNS species and that simple, reliable and inexpensive methods can be used for routine identification.
authors.affiliation: Department of Microbiology and Immunology, Botucatu Biosciences Institute, UNESP-University Estadual Paulista, Botucatu, SP, Brazil. adrianomartison@hotmail.com
authors.forename: Adriano Martison
authors.initials: AM
authors.lastname: Ferreira
authors.forename: Mariana Fávero
authors.initials: MF
authors.lastname: Bonesso
authors.forename: Alessandro Lia
authors.initials: AL
authors.lastname: Mondelli
authors.forename: Maria de Lourdes Ribeiro de Souza
authors.initials: Mde L
authors.lastname: da Cunha
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001671:Biochemistry / Q000379:methods*; D004269:DNA, Bacterial / Q000235:genetics; D021903:DNA, Ribosomal Spacer / Q000235:genetics*; D024881:Drug Resistance, Bacterial; D006801:Humans; D016133:Polymerase Chain Reaction / Q000379:methods*; D012336:RNA, Ribosomal, 16S / Q000235:genetics*; D012338:RNA, Ribosomal, 23S / Q000235:genetics*; D013203:Staphylococcal Infections / Q000382:microbiology*; D057790:Staphylococcus saprophyticus / Q000145:classification / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification*; D014552:Urinary Tract Infections / Q000382:microbiology*
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D021903:DNA, Ribosomal Spacer; D012336:RNA, Ribosomal, 16S; D012338:RNA, Ribosomal, 23S