Bacterial identification and antibiotic sensitivity profiles from captive birds at Taipei Zoo

Abstract

Bacterial infections are common in zoo birds. They may be caused by pathogenic bacteria or opportunistic bacteria
due to trauma or stress-induced immune compromise. Improper use of antibiotics contributes to the development of
resistant bacteria, making treatment complicated or ineffective. However, comprehensive clinical investigations into
bacterial prevalence and antibiotic susceptibility in zoo-captive birds remain limited. This study identified the bacterial
species present in captive diseased birds at the zoo and conducted a 12-year analysis of their antibiotic susceptibility
profiles. The specimens from 48 birds at Taipei Zoo from 2006 to 2017 were submitted to a commercial reference
laboratory for bacterial identification. Among the total of 48 birds, 36 were live diseased individuals designated for
further antibiotic susceptibility testing. A total of 105 bacteria were identified, and 75 were processed for antibiotic
susceptibility. The most frequently isolated bacterium was Escherichia coli (24.76%, Gram-negative facultative
anaerobe). Further antibiotic susceptibility testing using 33 different antibiotic discs revealed that only amikacin and
ceftazidime exhibited over 50% susceptibility against the Gram-negative facultative anaerobes. In addition, this study
observed a significant upward trend in E. coli resistance to kanamycin and neomycin, both of which belong to the
aminoglycosides. The prevalence of E. coli, a commensal bacterium, in captive birds at the zoo is a significant concern
due to the potential for horizontal transmission of antimicrobial resistance genes through contact between birds and
zoo personnel or visitors. Since aminoglycosides, either alone or in combination with other classes of antibiotics, are
commonly employed in wildlife treatment, these findings may provide valuable insights for future clinical applications
and the development of effective zoo management strategies.