Increase in Resistance to Extended-Spectrum Cephalosporins in Salmonella Isolated from Retail Chicken Products in Japan

Abstract

Extended-spectrum β-lactamase (ESBL)-producing Salmonella are one of the most important public health problems in developed countries. ESBL-producing Salmonella strains have been isolated from humans in Asian countries neighboring Japan, along with strains harboring the plasmid-mediated extended-spectrum cephalosporin (ESC)-resistance gene, ampC (pAmpC). However, only a few studies have investigated the prevalence of ESC-resistant Salmonella in chicken products in Japan, which are the main vehicle of Salmonella transmission. The aim of this study was to investigate the prevalence of ESBL-producing, pAmpC-harboring, or carbapenem-resistant Salmonella in chicken products in Japan. In total, 355 out of 779 (45.6%) chicken product samples collected from 1996–2010 contained Salmonella, resulting in 378 distinct isolates. Of these isolates, 373 were tested for resistance to ESCs, cephamycins, or carbapenems. Isolates that showed resistance to one or more of these antimicrobials were then examined by PCR and DNA sequence analysis for the presence of the bla CMY, bla CTX-M, bla TEM, and bla SHV resistance genes. Thirty-five resistant isolates were detected, including 26 isolates that contained pAmpC (bla CMY-2), and nine ESBL-producing isolates harboring bla CTX-M (n = 4, consisting of two bla CTX-M-2 and two bla CTX-M-15 genes), bla TEM (n = 4, consisting of one bla TEM-20 and three bla TEM-52 genes), and bla SHV (n = 1, bla SHV-12). All pAmpC-harboring and ESBL-producing Salmonella isolates were obtained from samples collected after 2005, and the percentage of resistant isolates increased significantly from 0% in 2004 to 27.9% in 2010 (P for trend = 0.006). This increase was caused in part by an increase in the number of Salmonella enterica subsp. enterica serovar Infantis strains harboring an approximately 280-kb plasmid containing bla CMY-2 in proximity to ISEcp1. The dissemination of ESC-resistant Salmonella containing plasmid-mediated bla CMY-2 in chicken products indicates the need for the development of continuous monitoring strategies in the interests of public health.

Characterization of a P1-like bacteriophage carrying CTX-M-27 in Salmonella spp. resistant to third generation cephalosporins isolated from pork in China

“…The emergence of Salmonella spp. isolates resistant to these drugs is of increasing public health concern45. Resistance to cephalosporins is principally by acquisition of plasmid carrying extended-spectrum β-lactamase (ESBL) genes, the most prevalent of which are the CTX-M-type ESBLs6.…”

Selection of broad‐spectrum cephalosporin‐resistant Escherichia coli in the feces of healthy dogs after administration of first‐generation cephalosporins

“…Information on bla CMY‐4 ‐carrying P. mirabilis isolated from a clinical sample from a dog is now available in Japan . In contrast, CTX‐M‐15 producers have been reported in E. coli and Salmonella from food‐producing animals . CTX‐M‐15‐producing E. coli were found in dogs in Japan in 2010 .…”

Screening for the Extended Spectrum Beta Lactamases Among Salmonella Spp. Isolated From Broiler Chicken in Egypt.

“…The incidence of extended spectrum cephalosporin resistant Salmonella has increased in several countries (Noda et al, 2015). In Egypt, cephalosporin resistant Salmonella isolates from chicken meat have been reported (Ahmed and Shimamoto, 2015).…”