Factors for Occurrence of Extended-Spectrum β-Lactamase-Producing <i>Escherichia coli</i> in Broilers

Abstract

ABSTRACT. To clarify the factors for occurrence of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli in broilers, two flocks (1 day of age) fed a diet with or without antibiotics were kept in a broiler house sanitized with disinfectants. ESBL-producing E. coli, however, was detected at a concentration of over 10 6 CFU/g of feces at 9 days of age to 49 days of age in both broiler flocks. Therefore, this indicated that the antibiotics other than cephalosporins used in this study had no effect due to co-selection on the numbers of ESBL-producing E. coli in broiler feces during this period. When a flock was kept with diet containing antibiotics for 49 days in a laboratory animal room, no ESBL-producing E. coli was detected in the flock. These results suggest that the occurrence of ESBL-producing E. coli may not be related to feeding with antibiotics and that the contamination of broiler houses with ESBL-producing E. coli might be an important factor. KEY WORDS: antibiotics, broiler, Escherichia coli, extended-spectrum β-lactamase-producing, occurrence. Extended-spectrum β-lactamase (ESBL)-producing bacteria have antibiotic resistance to third generation cephalosporins such as cefotaxime (CTX). Reports on Escherichia coli carrying broad-spectrum β-lactamases isolated from food-producing animals and humans have been published worldwide [8]. ESBL-producing Klebsiella pneumoniae, E. coli and Proteus mirabilis have been implicated in numerous outbreaks of nosocomial infections over the last 2 decades [3,10,13]. CTX-M-2-producing E. coli from cattle in Japan has been reported [11], and the Japanese Veterinary Antimicrobial Resistance Monitoring Program (JVARM) reported isolation of ESBL-producing E. coli from poultry in Japan [6]. In addition, a potential increase in the ESBLproducing E. coli isolated from broilers was also reported [4]. Our previous study [5] clarified the high prevalence of ESBL-producing commensal enteric bacteria in broilers in Japan. However, use of third-generation cephalosporins on broilers is not permitted in Japan. The factors of occurrence of ESBL-producing E. coli in broiler are still unclear. The aim of this study was to clarify these factors.Two flocks with 16 broilers each (Chunky, 1 day of age) were newly introduced to a hygienic broiler house sanitized with disinfectants. Although this windowless broiler house had been maintained in all-in-all-out system and sanitized with disinfectants immediately after all the broilers were marketed, ESBL-producing E. coli strains had been isolated from broiler feces collected in this broiler house in the last two examinations. A flock fed a diet with antibiotics (salinomycin 50 ppm and enramycin 7 ppm from 1 to 21 days of age; salinomycin sodium salt 50 ppm, gentamycin 5 ppm and colistin sulfate 5 ppm from 22 to 42 days of age; no antibiotics from 43 to 49 days of age), and another flock without antibiotics was raised until 49 days of age with hygienic water. The broiler house operating procedures were conventional. Harada et al. [2] repor...

Longitudinal Monitoring of Extended-Spectrum-Beta-Lactamase/AmpC-Producing Escherichia coli at German Broiler Chicken Fattening Farms

“…Thus, detailed investigation of possible vertical transmission routes of ESBL/AmpC-producing E. coli from hatching eggs to the day-old chicks is of fundamental importance and should be considered in further studies. In contrast to Mevius et al (30), a study presented by Hiroi et al (31) assumed contaminated barns as a consequence of insufficient cleaning and disinfection as a cause for high incidences of ESBL/ AmpC-producing E. coli in broiler farms. The positive findings for various environmental samples at the first sampling date in our study support this hypothesis.…”

Environmental adaptation and vertical dissemination of ESBL‐/pAmpC‐producing Escherichia coli in an integrated broiler production chain in the absence of an antibiotic treatment

“…ESBL‐/pAmpC‐producing Enterobacteriaceae were frequently isolated from broiler fattening farms worldwide (Bortolaia et al ., 2010; Randall et al ., 2011; Kameyama et al ., 2013; Maciuca et al ., 2015; Trongjit et al ., 2016) but were also found in broiler (grand) parent flocks (Dierikx et al ., 2013; Agersø et al ., 2014; Mo et al ., 2014; Zurfluh et al ., 2014). Therefore, different transmission scenarios of the resistant bacteria in the broiler production pyramid are discussed: A transmission from prior stages into the fattening farms (Giovanardi et al ., 2005; Dierikx et al ., 2013; Nilsson et al ., 2014; Huijbers et al ., 2016) as well as an insufficient cleaning and disinfection procedure in the chicken barns (Hiroi et al ., 2012; Luyckx et al ., 2015b). We recently showed a pseudo‐vertical transfer of resistant bacteria from the parent flocks into the hatchery via contaminated eggshells (Projahn et al ., 2017).…”

Susceptibility to disinfectants in antimicrobial-resistant and -susceptible isolates of Escherichia coli, Enterococcus faecalis and Enterococcus faecium from poultry-ESBL/AmpC-phenotype of E. coli is not associated with resistance to a quaternary ammonium

“…Extended‐spectrum beta‐lactamase (ESBL)‐producing strains had been found to spread independently of β‐lactam use in broilers in the past (Hiroi et al . ); it has been assumed that reduced susceptibility to disinfectants might be one factor currently associated with the high prevalence of ESBL‐producing strains in poultry (Shrivastav et al . ).…”