Characterization of multiple-antibiotic-resistant Salmonella typhimurium strains : Molecular epidemiology of PER-1-producing isolates and evidence for nosocomial plasmid exchange by a clone

We characterized epidemiologic and genetic features of nosocomially originated multiple-antibiotic-resistant Salmonella typhimurium isolates from two hospitals. A total of 32 multiply resistant strains, isolated during a 28-month period, were studied. Four resistance phenotypes were distinguished on...

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Bibliographic Details
Published in:Journal of clinical microbiology 1996-12, Vol.34 (12), p.2942-2946
Main Authors: VAHABOGLU, H, DODANLI, S, EROGLU, C, ÖZTÜRK, R, SOYLETIR, G, YILDIRIM, I, AVKAN, V
Format: Article
Language:English
Subjects:
Bacteriology
Biological and medical sciences
Epidemiology
Fundamental and applied biological sciences. Psychology
Microbiology
Salmonella typhimurium
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Summary:We characterized epidemiologic and genetic features of nosocomially originated multiple-antibiotic-resistant Salmonella typhimurium isolates from two hospitals. A total of 32 multiply resistant strains, isolated during a 28-month period, were studied. Four resistance phenotypes were distinguished on the basis of the results of disc diffusion tests. Group 1 was resistant to chloramphenicol, gentamicin, tobramycin, amikacin, and the newer cephalosporins because of the production of an extended-spectrum beta -lactamase (PER-1). Group 2 exhibited the same pattern plus resistance to sulfamethoxazole-trimethoprim (Sxt). Except for Sxt resistance, dominant phenotypes of both groups were transferred on an identical plasmid, pSTI1 (81 MDa). Group 3 was resistant to ampicillin, chloramphenicol, gentamicin, tobramycin, and Sxt. This pattern was also transferred on an 81-MDa plasmid (pSTI2) which differed from pSTI1 on the basis of EcoRI and HindIII restriction fragments. Group 4 was resistant to ampicillin, chloramphenicol, and tetracycline, and a 74-MDa nonconjugative plasmid was detected. Restriction fragment length polymorphism of RNA-encoding DNA and arbitrarily primed PCR tests revealed that bacteria from groups 1, 2, and 3 were clonally related. Epidemiologic data also supported the clonal-dissemination hypothesis. We conclude that S. typhimurium isolates acquire and exchange multiple-resistance plasmids in hospital microflora.
ISSN:0095-1137
1098-660X
DOI:10.1128/jcm.34.12.2942-2946.1996