Antimicrobial resistance, virulence factors and genetic lineages of hospital-onset methicillin-resistant Staphylococcus aureus isolates detected in a hospital in Zaragoza

Abstract

Please cite this article in press as: González-Domínguez M, et al. b s t r a c tIntroduction: MRSA population dynamics is undergoing significant changes, and for this reason it is important to know which clones are circulating in our nosocomial environment. Materials and methods: A total of 118 MRSA isolates were collected from clinical samples from patients with previous hospital or healthcare contact (named as hospital-onset MRSA (HO-MRSA)) during a one year period. Susceptibility testing was performed by disk diffusion and microdilution. The presence of resistance genes and virulence factors were tested by PCR. All isolates were typed by SCCmec, spa and agr typing. PFGE and MLST were applied to a selection of them.Results: Eighty-three HO-MRSA isolates (70.3%) were resistant to any antibiotic included in the macrolide-lincosamide-streptogramin B group. Among these isolates, the M phenotype was the most frequent (73.5%). One hundred and seven of HO-MRSA isolates (90.7%) showed aminoglycoside resistance. The combination aac(6 )-Ie-aph(2 )-Ia + ant (4 ) El CC5 fue el más prevalente (88,1%) seguido de CC8 (5,9%), CC22 (2,5%), CC398 (2,5%) y CC1 (0,8%). Conclusión: La línea clonal CC5/ST125/t067 fue la más habitual. Esta línea se relacionó con resistencia a aminoglucósidos, y, en menor medida, con macrólidos. La presencia de clones internacionales como EMRSA-15 (CC22/ST22), clones europeos como CC5/ST228, clones comunitarios relacionados con CC1 o CC8 y clones asociados al ganado, como el CC398, se observaron en un bajo porcentaje. ARTICLE IN PRESSG Model EIMC 1282 1-7 2 M. González-Domínguez et al. / Enferm Infecc Microbiol Clin. 2015;xxx(xx):xxx-xxx

Genotypic and phenotypic characterization of methicillin-resistant Staphylococcus aureus (MRSA) clones with high-level mupirocin resistance

“…During the course of this study, MRSA prevalence in our hospital was 30.9%, consistent with other resistance rates found in different Spanish hospitals (Cuevas et al, 2008;González-Domínguez et al, 2015;Lozano et al, 2013). Forty MRSA isolates showed HLMUPR, representing 27.2% of the studied isolates (mupirocin MICs ≥ 256 mg/L).…”

“…An association between MRSA CC5/ST125/t067 and erythromycin resistance (encoded by msr(A)/msr(B) genes) has been observed. This relation was previously described by other authors (Daskalaki et al, 2009;González-Domínguez et al, 2015;Lozano et al, 2013;Pérez-Roth et al, 2013). All HLMUPR-MRSA strains carried SCCmec type IVc and agr type II, with the exception of one strain included in SCCmec type V that belonged to ST125.…”

“…The spa type t067 was the predominant one (82%), although this spa type was also frequent in mupirocin-susceptible group (52%) where 22 different spa types were found. spa type t067 is the most frequent spa type identified in Spain (Argudín et al, 2009;González-Domínguez et al, 2012, 2015Lozano et Menegotto et al, 2012), so this fact could be the reason for its high prevalence in both groups. Among the HLMUPR-MRSA strains, 97.5% of them belonged to ST125 and 2.5% to ST5.…”

“…Among the HLMUPR-MRSA strains, 97.5% of them belonged to ST125 and 2.5% to ST5. Both ST are included in CC5, widely distributed in hospital and community settings in Spain (Argudín et al, 2009;González-Domínguez et al, 2012, 2015Lozano et al, 2013). An association between MRSA CC5/ST125/t067 and erythromycin resistance (encoded by msr(A)/msr(B) genes) has been observed.…”