Clinical outcomes of nalidixic acid, ceftriaxone, and multidrug-resistant nontyphoidal salmonella infections compared with pansusceptible infections in FoodNet sites, 2006-2008.

Background: Nontyphoidal Salmonella causes an estimated 1.2 million infections, 23,000 hospitalizations, and 450 deaths annually in the United States. Most illnesses are self-limited; however, treatment with antimicrobial agents can be life-saving for invasive infections.

Antimicrobial resistance genes in multidrug-resistant Salmonella enterica isolated from animals, retail meats, and humans in the United States and Canada.

Salmonella enterica is a prevalent foodborne pathogen that can carry multidrug resistance (MDR) and pose a threat to human health. Identifying the genetics associated with MDR in Salmonella isolated from animals, foods, and humans can help determine sources of MDR in food animals and their impact on humans. S.

Characterization of bla(CMY)-encoding plasmids among Salmonella isolated in the United States in 2007.

Salmonella enterica is one of the most common bacterial causes of foodborne illness, and nontyphoidal Salmonella is estimated to cause ∼1.2 million illnesses in the United States each year. Plasmids are mobile genetic elements that play a critical role in the dissemination of antimicrobial resistance determinants.

Ciprofloxacin-resistant Salmonella enterica Serotype Typhi, United States, 1999-2008.

We report 9 ciprofloxacin-resistant Salmonella enterica serotype Typhi isolates submitted to the US National Antimicrobial Resistance Monitoring System during 1999-2008. The first 2 had indistinguishable pulsed-field gel electrophoresis patterns and identical gyrA and parC mutations. Eight of the 9 patients had traveled to India within 30 days before illness onset.

Decreased susceptibility to ciprofloxacin among Shigella isolates in the United States, 2006 to 2009.

We characterized 20 Shigella isolates with decreased susceptibility to fluoroquinolones. Most patients (80%) from whom a travel history was obtained reported travel to South or Southeast Asia. Mutations within the quinolone resistance determining regions of gyrA and parC and plasmid-mediated resistance determinants (qnrB, qnrS, and aac(6')-Ib-cr) were identified.

CTX-M-producing non-Typhi Salmonella spp. isolated from humans, United States.

CTX-M-type beta-lactamases are increasing among US Enterobacteriaceae isolates. Of 2,165 non-Typhi Salmonella isolates submitted in 2007 to the National Antimicrobial Resistance Monitoring System, 100 (4.6%) displayed elevated MICs (≥2 mg/L) of ceftriaxone or ceftiofur.

Plasmid-mediated quinolone resistance among non-Typhi Salmonella enterica isolates, USA.

We determined the prevalence of plasmid-mediated quinolone resistance mechanisms among non-Typhi Salmonella spp. isolated from humans, food animals, and retail meat in the United States in 2007. Six isolates collected from humans harbored aac(6')Ib-cr or a qnr gene.

Salmonella isolates with decreased susceptibility to extended-spectrum cephalosporins in the United States.

Objective: We describe the antimicrobial susceptibility to extended-spectrum cephalosporins in non-Typhi Salmonella (NTS) isolated from humans in the United States and explore resistance mechanisms for isolates displaying decreased susceptibility to ceftriaxone or ceftiofur. We further explore the concordance between the newly revised Clinical and Laboratory Standards Institute (CLSI) breakpoints for ceftriaxone and the presence of a β-lactamase.

Methods: In 2005 and 2006, public health laboratories in all U.

Characterization of extended-spectrum cephalosporin-resistant Salmonella enterica serovar Heidelberg isolated from humans in the United States.

During the past decade, extended-spectrum cephalosporin resistance has increased among human isolates of Salmonella enterica serovar Heidelberg, the fourth most common serotype in the United States. We therefore characterized 54 Heidelberg isolates with decreased susceptibility (minimum inhibitory concentrations >or=2 mg/L) to ceftriaxone or ceftiofur; 49 (90.7%) contained the CMY-type beta-lactamase (bla(CMY)) gene.

Emergence of plasmid-mediated quinolone resistance among non-Typhi Salmonella enterica isolates from humans in the United States.

Plasmid-mediated quinolone resistance determinants are emerging among gram-negative pathogens. Here we report results of a retrospective study investigating the prevalence of aac(6')-Ib-cr, qepA, and qnr genes among 19,010 human isolates of non-Typhi Salmonella enterica collected in the United States from 1996 to 2006.