DETERMINAZIONE DELLE CARATTERISTICHE FENOTIPICHE E GENOTIPICHE DI CEPPI DI STAPHYLOCOCCUS IN RELAZIONE A METICILLINO- E VANCOMICINO-RESISTENZA
Tesi di Dottorato
Data di Pubblicazione:
2012
Citazione:
DETERMINAZIONE DELLE CARATTERISTICHE FENOTIPICHE E GENOTIPICHE DI CEPPI DI STAPHYLOCOCCUS IN RELAZIONE A METICILLINO- E VANCOMICINO-RESISTENZA / M.m. Ferretti ; tutor: P. Dall'Ara ; coordinatore: F. Gandolfi. Universita' degli Studi di Milano, 2012 Feb 03. 24. ciclo, Anno Accademico 2011. [10.13130/ferretti-manuela-maria_phd2012-02-03].
Abstract:
OBJECTIVE – The aim of the study was to evaluate the phenotypic and genotypic characteristics of
methicillin-resistant Staphylococcus pseudintermedius in samples from dogs and cats processed in
the laboratory of a veterinarian teaching hospital. We also performed tests for vancomycinresistance
on the same isolates.
MATERIALS AND METHODS – A total of 36 strains of Staphylococcus were isolated from 33 dogs
and 3 cats (from skin, eyes, ears, urine, surgical wounds and others). The strains were identified by
cultivation on selective medium (MSA), by biochemical system (API-Staph®) and by molecular
method (HRM-PCR). The evaluation of the resistance pattern of the strains was performed using
Kirby-Bauer method, testing different antimicrobial classes in addition to methicillin and
vancomycin. We also performed MIC for methicillin and vancomycin. The presence of mecA gene
was evaluated by PCR.
RESULTS – 31 strain of S. pseudintermedius, 1 strain of S. aureus and 4 strains of other
Staphylococcus species were identified by HRM-PCR method. Among the 36 strains of S.
pseudintermedius isolated, 19 were phenotypically resistant to methicillin and 16 of these MRSP
carried the mecA gene. The 50% of the 36 isolates were found to be multiresistant and 16 of these
strains were also methicillin-resistant. No vancomycin-resistant strains were found.
CONCLUSIONS – This study confirmed the increasing prevalence of MRSP and the absence so far
of vancomycin-resistance in strains of Staphylococcus isolated from small domestic animals. The
most reliable methods for the identification of species were the molecular ones, instead of the
biochemical, less effective to have conclusive results.
Tipologia IRIS:
Tesi di dottorato
Keywords:
Staphylococcus pseudintermedius ; methicillin-resistance ; vancomycin-resistance ; mecA
Elenco autori:
M.M. Ferretti
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