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Seminar 930

Date:2022-05-03 Update:2022-12-30

Antimicrobial-Resistant Escherichia coli isolates from Diseased Animals

Nan-Ling Kuan



Extended-spectrum β-lactamases (ESBLs) are a rapidly evolving group of β-lactamases that shares the ability to hydrolyze third-generation antibiotics, such as cephalosporins, penicillins, and aztreonam. Since 2000, extended-spectrum beta-lactamase producing Escherichia coli  (ESBL-EC) infections have increased worldwide in humans, as well as food and companion animals. In this study, 569 E. coli isolates from diseased animals, which were obtained from 2013 to 2020, were analysed for anitimicrobial resistance. Sixty-seven out of 569 isolates were confirmed by phenotyping and genotyping to ESBL-EC, with most of them encoding the bla genes, such as blaCTX-M (77.6%), blaTEM (14.9%), and blaSHV (1.5%), while some isolates even encoded bla genes from two groups. The dominant bla gene variant was blaCTX-M-55, followed by blaCTX-M-14. All ESBL-ECs were resistant to tetracycline, while more than 90% of the strains were resistant to ceftiofur and SXT (92.5-97%). The analyzed ESBL-ECs displayed less resistance to gentamycin (64.2%), enrofloxacin (53.7%), and amoxicillin (32.8%). All isolates in this study remained susceptible to imipenem.


Epidemiology of bovine tuberculosis  in Taiwan cattle

Chen-Shen Huang


Bovine tuberculosis (bTB) is an important zoonotic disease caused by Mycobacterium bovis. Although, cattle are considered to be the main hosts, most mammals can be infected by M. bovis. Depending on the route of infection, characteristic nodular lesions can be observed in lymph nodes of the head and chest, or in abdominal organs. The intradermal tuberculin test (ITT) is the standard method for testing bovine tuberculosis, in particular, to ensure the safety of the international trade market. It is also the standard method for bovine tuberculosis detection in Taiwan. We analyzed bTB positive cases in Taiwan from 2019 to 2021, and discovered, that since the second half of 2020, many cases have been found in slaughterhouses, and that the number of farms with positive cases increased. The M. bovis isolates were genotyped by two genotyping methods commonly used within the Mycobacterium tuberculosis complex for molecular epidemiological analysis: spoligotyping and the use of MIRU/VNTR typing (three loci, ETR-A, ETR-B, and Qub11b). A total of 12 genotypes were obtained in 2021, the most in history.

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