Search

We evaluated the prevalence and epidemiology of extended‐spectrum beta‐lactamase (ESBL)‐producing Escherichia coli isolates in pigs during production cycle on a Czech farm with the history of previous use of ceftiofur. ESBL‐producing E. coli isolates were obtained from rectal swabs from pigs of different age groups (suckling piglets, weaned piglets, growers and sows). Collected samples were directly cultivated on MacConkey agar with cefotaxime (2 mg l−1), whereas intestinal swabs of slaughtered pigs and surface swabs from pig carcasses were also pre‐enriched in buffered peptone water without antimicrobials before the cultivation. Clonal relationship of selected isolates was determined by XbaI pulse‐field gel electrophoresis and multi‐locus sequence typing. The transferability of plasmids carrying blaCTX‐M genes was tested by conjugation experiments. From all examined samples, 141 (43·7%, n = 323) were positive for ESBL‐producing E. coli. All ESBL‐producing isolates showed resistance to multiple antimicrobials and were positive for blaCTX‐M genes. The blaCTX‐M‐1 was carried by conjugative IncN/ST1 plasmids (c. 40–45 kb) while the blaCTX‐M‐15 was located on conjugative F plasmids with F:18:A5:B1 formula (c. 165 kb). This study demonstrated the persistence of CTX‐M‐positive E. coli isolates 2 months after banner of ceftiofur usage and indicated possible risk of transmission of these isolates to humans via the food chain. [ABSTRACT FROM AUTHOR]

Abstract: The spread of antimicrobial resistance from human activity derived sources to natural habitats implicates wildlife as potential vectors of antimicrobial resistance transfer. Wild birds, including corvid species can disseminate mobile genetic resistance determinants through faeces. This study aimed to determine the occurrence of plasmid‐mediated quinolone resistance (PMQR) genes in Escherichia coli and Klebsiella spp. isolates obtained from winter roosting sites of American crows (Corvus brachyrhynchos) and common ravens (Corvus corax) in Canada. Faecal swabs were collected at five roosting sites across Canada. Selective media isolation and multiplex PCR screening was utilized to identify PMQR genes followed by gene sequencing, pulse‐field gel electrophoresis and multilocus sequence typing to characterize isolates. Despite the low prevalence of E. coli containing PMQR (1·3%, 6/449), qnrS1, qnrB19, qnrC, oqxAB and aac(6′)‐Ib‐cr genes were found in five sequence types (ST), including E. coli ST 131. Conversely, one isolate of Klebsiella pneumoniae contained the plasmid‐mediated resistance gene qnrB19. Five different K. pneumoniae STs were identified, including two novel types. The occurrence of PMQR genes and STs of public health significance in E. coli and Klebsiella pneumoniae recovered from corvids gives further evidence of the anthropogenic derived dissemination of antimicrobial resistance determinants at the human activity‐wildlife‐environment interface. Significance and Impact of the Study: This study examined large corvids as possible vector species for the dissemination of antimicrobial resistance in indicator and pathogenic bacteria as a means to assess the anthropogenic dissemination of plasmid‐mediated quinolone resistance (PMQR) genes. Although rare, PMQR genes were found among corvid populations across Canada. The clinically important Escherichia coli strain ST131 containing aac(6′)‐Ib‐cr gene along with a four‐class phenotypic antimicrobial resistance (AMR) pattern as well as one Klebsiella pneumoniae strain containing a qnrB19 gene were identified in one geographical location. Corvids are a viable vector for the circulation of PMQR genes and clinically important clones in wide‐ranging environments. [ABSTRACT FROM AUTHOR]