Affiliation:
1. Department of Functional Biology, Microbiology Area, University of Oviedo, Julian Clavería 6, E-33006 Oviedo, Spain
2. Department of Biological Safety, Federal Institute for Risk Assessment (BfR), Thielalle 88-92, D-14195 Berlin, Germany
Abstract
ABSTRACT
A series of 100
Staphylococcus aureus
isolates ascribed to sequence type 398 (ST398) and recovered from different sources (healthy carrier and diseased pigs, dust from pig farms, milk, and meat) in Germany were investigated for their virulence and antimicrobial resistance genetic background. Antimicrobial resistance was determined by the disk diffusion method. Virulence and resistance determinants (37 and 31 genes, respectively) were tested by PCR. Only two virulence profiles, including the accessory gene regulator
agrI
and three or four hemolysin-encoding genes, were detected. In contrast, 33 resistance profiles were distinguished (only 11 were shown by more than one isolate). Fifty-nine isolates were multiresistant (four or more antimicrobial classes), and 98 were methicillin resistant (
mecA
positive). All of the ST398 isolates showed resistance to tetracycline [encoded by
tet
(M) alone or together with
tet
(K) and/or
tet
(L)]. In addition, 98% were resistant to other antimicrobials, including macrolide-lincosamine-streptogramin B (70%, encoded by
ermA
,
ermB
, and
ermC
, alone or in combination), trimethoprim (65%, mostly due to
dfrK
and
dfrG
), kanamycin and gentamicin [29% and 14%, respectively, mainly related to
aac
(
6
′
)-Ie-aph
(
2
″
)-Ia
and/or
ant(4
′
)-Ia
but also to
aph(3
′
)-IIIa
], chloramphenicol (9%,
fexA
or
cfr
), quinupristin-dalfopristin (9%), ciprofloxacin (8%), and trimethoprim-sulfamethoxazole (4%). The heterogeneity of the resistance profiles underlines the ability of the ST398 clone to acquire multiple antimicrobial resistance genes. However, the virulence gene content of the tested isolates was low. Continuous surveillance is needed to clarify whether its pathogenicity potential for animals and humans will increase over time.
Publisher
American Society for Microbiology
Subject
Ecology,Applied Microbiology and Biotechnology,Food Science,Biotechnology
Cited by
182 articles.
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