Forty-six Yersinia enterocolitica O:3 clinical isolates resistant to nalidixic acid were studied. The use of molecular typing techniques, other indicators of resistance patterns, the plasmid profile, and the presence of genes that encode aminoglycoside-modifying enzyme production suggested to us a clonal dissemination of the studied strains.

Ten epidemiologically related Yersinia enterocolitica clinical isolates were studied. Six isolates were nalidixic acid resistant (MIC > 512 microg/ml), with mutations in the quinolone resistance-determining region (QRDR) of the gyrA gene, suggesting clonal dissemination of a nalidixic acid-susceptible Y. enterocolitica strain which has acquired different mutations generating resistance to nalid...

The epidemiological study of several multidrug-resistant Enterobacteriaceae isolated from five patients demonstrated in vivo dissemination of a 100-kb plasmid encoding the extended-spectrum beta-lactamase TEM-24 from a clonal strain of Enterobacter aerogenes to different strains of Klebsiella pneumoniae, Escherichia coli, Proteus vulgaris, Proteus mirabilis, and Serratia marcescens.

We compared antimicrobial resistance patterns of Salmonella enterica serovar Typhimurium (ST) of isolates from humans (n = 715) and cattle (n = 378) in the Pacific Northwest from 1982 through 1997. The major changes in antimicrobial resistance can be attributed to the widespread clonal dissemination of multidrug-resistant definitive phage type 104 ST.

Between 1998 and 2003 the rate of erythromycin resistance among pneumococci in Spain was 34.4%. Although the MLS(B) phenotype was prevalent (94.7%), the rate of the M phenotype increased from 3.3% to 8.9% (P < 0.01). Clonal dissemination of mef(E)-carrying strains of serotype 14 variant of the Spain(9V)-3 clone was the major contributor to this increase.

Vancomycin-resistant Enterococcus faecium strains (VRE) were isolated from human wastewater but not swine fecal waste from a semiclosed agri-food system in Texas. Forty-nine VRE isolates possessed vanA, and one possessed vanB. Twenty-one pulsed-field gel electrophoresis types were identified and segregated into three groups. There was evidence of clonal dissemination among geographically separa...

The microbial contamination of air filters and possible links to contaminated product in a powdered milk protein-processing facility were investigated. Over a 10-month period, seven air filters, the environment, and powdered product were analyzed for the presence of Cronobacter spp. The effects of air filter installation, maintenance, and subsequent dissemination of Cronobacter were investigate...

The ability of Pseudomonas aeruginosa to develop resistance to most antimicrobials represents an important clinical threat worldwide. We report the dissemination in several Colombian hospitals of two predominant lineages of extensively drug-resistant (XDR) carbapenemase-producing P. aeruginosa strains. These lineages belong to the high-risk clones sequence type 111 (ST111) and ST235 and harbor ...

BACKGROUND Pseudomonas aeruginosa is an opportunistic pathogen associated with nosocomial infections. The emergence and dissemination of metallo-beta-lactamases (MBLs) has contributed to the high rate of resistance among P. aeruginosa isolates. OBJECTIVES The purpose of this study was to describe the prevalence and the clonal dissemination of MBL- producing P. aeruginosa isolates collected fr...