Corrigendum: Transduction as a Potential Dissemination Mechanism of a Clonal qnrB19-Carrying Plasmid Isolated From Salmonella of Multiple Serotypes and Isolation Sources

Molecular characterization of PMQR carrying bacteriophages in effluent discharge samples of Azerbaijan hospitals

Quinolones are one of the most widely used drugs in medicine. Resistance to this agent has been increased significantly among the nosocomial isolates. The objective of this research was to study generalized transduction, as a potential mechanism for plasmid-mediated quinolone resistance (PMQR) genes acquisition among hospital effluent isolates. Discharge samples from hospital effluent were taken from four medical centers in Azerbaijan. Resident phages were enriched against resident enterobacterial hosts using standard phage enrichment protocols. Polymerase chain reaction (PCR) was used to examine phage stocks and bacterial isolates for the presence of PMQR determinants. All positive bacterial isolates for target genes were subjected to transduction assays. Restriction fragment length polymorphism (RFLP) profiles were determined for cluster analysis. A total of 55 pure phage stocks were prepared from 42 effluents. A total of 95 non-duplicated Gram-negative bacteria were isolated. Thirty-two EcoRV-RFLP profiles were determined for the 40 Escherichia coli phage stocks. Twenty-six of 40 (65%) E. coli phages were positive for qnrB (n = 15), qnrD (n = 7), qnrA (n = 3), and qnrC (n = 2) genes. A total of 34 (35.7%) bacterial isolates were recognized to have any PMQR genes including qnrB (n = 23), qnrD (n = 8), qnrA (n = 5), and qnrC (n = 3) genes. Present research provided a strong evidence for potential role of generalized transduction in persistence and circulation of PMQR genes in health care settings of Azerbaijan.

Multidrug-resistant Salmonella spp. in fecal samples of pigs with suspected salmonellosis in Antioquia, Colombia, 2019-2021

Objectives

To determine the proportion of Salmonella enterica in fecal samples of live pigs with suspected salmonellosis analyzed at the diagnostic unit of the University of Antioquia, Colombia between 2019 and 2021, and examine the serotypes and antimicrobial resistance patterns.

Methods

This was a laboratory-based cross-sectional study of routine data on fecal samples received from pig farms in all nine subregions of Antioquia state, Colombia. Salmonella spp. detection at the university is done using enrichment, selective culture, and polymerase chain reaction. Serotypes were identified using the Kauffmann-White scheme and isolates were tested for antimicrobial susceptibility using broth microdilution.

Results

Of 653 samples tested, 149 (23%) were positive for S. enterica. Nine serotypes were identified. The most common were Salmonella Typhimurium (56%) and its monophasic variant (35%). Resistance to ampicillin (70%) was most frequently observed, followed by ciprofloxacin (55%), and sulfamethoxazole-trimethoprim (52%). No isolates were resistant to amikacin and gentamicin. Multidrug resistance (resistance to ≥ 3 classes of antibiotics) was observed in 61 (44%) isolates. Multidrug resistance was highest in S. Typhimurium (57%) compared with the other serotypes. Serotype was associated with multidrug resistance (p = 0.01), but age of the pig and sub-region were not.

Conclusions

The proportion of Salmonella spp. and the associated high levels of multidrug resistance are of concern and may indicate irrational use of antimicrobials and poor management practices in pig production systems in the region. Strengthened surveillance is needed to monitor and improve farm management practices and the use of antimicrobials in farms in Colombia.

A National Antimicrobial Resistance Monitoring System Survey of Antimicrobial-Resistant Foodborne Bacteria Isolated from Retail Veal in the United States

ABSTRACT

Little is known about the prevalence of antimicrobial-resistant (AMR) bacteria in veal meat in the United States. We estimated the prevalence of bacterial contamination and AMR in various veal meats collected during the 2018 U.S. National Antimicrobial Resistance Monitoring System (NARMS) survey of retail outlets in nine states and compared the prevalence with the frequency of AMR bacteria from other cattle sources sampled for NARMS. In addition, we identified genes associated with resistance to medically important antimicrobials and gleaned other genetic details about the resistant organisms. The prevalence of Campylobacter, Salmonella, Escherichia coli, and Enterococcus in veal meats collected from grocery stores in nine states was 0% (0 of 358), 0.6% (2 of 358), 21.1% (49 of 232), and 53.5% (121 of 226), respectively, with ground veal posing the highest risk for contamination. Both Salmonella isolates were resistant to at least one antimicrobial agent as were 65.3% (32 of 49) of E. coli and 73.6% (89 of 121) of Enterococcus isolates. Individual drug and multiple drug resistance levels were significantly higher (P < 0.05) in E. coli and Enterococcus from retail veal than in dairy cattle ceca and retail ground beef samples from 2018 NARMS data. Whole genome sequencing was conducted on select E. coli and Salmonella from veal. Cephalosporin resistance (blaCMY and blaCTX-M), macrolide resistance (mph), and plasmid-mediated quinolone resistance (qnr) genes and gyrA mutations were found. We also identified heavy metal resistance genes ter, ars, mer, fieF, and gol and disinfectant resistance genes qac and emrE. An stx1a-containing E. coli was also found. Sequence types were highly varied among the nine E. coli isolates that were sequenced. Several plasmid types were identified in E. coli and Salmonella, with the majority (9 of 11) of isolates containing IncF. This study illustrates that veal meat is a carrier of AMR bacteria.

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