Prevalence, resistance profile, and molecular epidemiology of extended-spectrum β-lactamases producing Escherichia coli from captive giant pandas.
The prevalence of ESBL-producing E. coli in captive giant pandas has risen sharply to 29.0%, with all strains showing high resistance to key antibiotics.
Where it sits
this study against the rest of the ll-37 corpusSummary and findings
This study measured the prevalence and antibiotic resistance of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli in captive giant pandas. A total of 100 isolates from individual pandas were screened, revealing a prevalence of 29.0%. The isolates exhibited 100.0% resistance to several β-lactam antibiotics.
Abstract
Background/objective Extended-spectrum β-lactamase (ESBL)-producing Escherichia coli (E. coli), a bacterium resistant to most β-lactam antibiotics, is a critical clinical global health concern, posing significant health risks to humans and animals including giant pandas. The Chengdu Research Base of Giant Panda Breeding (CRBGP) has the world's largest captive population of giant pandas. This study aimed to investigate the prevalence, antibiotic resistance characteristics, and molecular epidemiology of ESBL-producing E. coli among captive giant pandas at the CRBGP. Methods ESBL production was screened in 100 E. coli isolates from 100 individual giant pandas (different ages and sexes) using the Clinical and Laboratory Standards Institute (CLSI) double-disc combination test. ESBL isolates were subjected to antimicrobial susceptibility testing of 34 antibiotics using the Kirby-Bauer disk diffusion susceptibility test (K-B). Whole genome sequencing (WGS) was performed to characterize genotypes, antibiotic resistance genes (ARGs), mobile genetic elements (MGEs), and multilocus sequence typing (MLST), and the molecular epidemiology of the isolates was further investigated using MLST and the goeBURST algorithm. Results Twenty-nine ESBL-producing E. coli strains were identified (29.0%, 29/100), representing a marked increase from the 8% prevalence reported during 2020-2021. All 29 isolates exhibited high resistance to β-lactam antibiotics, with 100.0% resistance to amoxicillin, ampicillin, cefazolin, cefuroxime and cefotaxime. A total of 120 different ARG subtypes and 19 ESBL gene subtypes were detected; bla CTX-M-4 was the most prevalent (100.0%), followed by bla SHV-1 (96.6%), bla CTX-M-1 and bla CTX-M-3 (93.1% each). Analysis of MGEs revealed high carriage rates of IS26 (89.7%), intI1 (89.7%), and the conjugation-associated gene traA (51.7%). MLST identified 10 sequence types (STs) and one clonal complex (CC1), with ST132 as the founder. ST595 and ST973 were the most common STs (each n = 7). Conclusions The prevalence of ESBL-producing E. coli in captive giant pandas at the CRBGP has risen sharply (29.0%), with high-level multidrug resistance (MDR), a large ARG repertoire, and abundant MGEs indicative of strong horizontal gene transfer (HGT) potential. The presence of shared STs with other hosts suggests potential interspecies transmission. These findings underscore the urgent need for enhanced antimicrobial stewardship and continuous One Health surveillance to protect giant pandas and the broader ecosystem.
Background
The study addresses the prevalence and resistance profiles of ESBL-producing E. coli, which pose significant health risks to both humans and animals. Prior research indicated lower prevalence rates of 8% during 2020-2021. Understanding the current resistance patterns in captive giant pandas is crucial for public health and conservation efforts.
Methods
The study utilized a screening of 100 E. coli isolates from 100 individual giant pandas, employing the CLSI double-disc combination test for ESBL production. Antimicrobial susceptibility was tested against 34 antibiotics using the Kirby-Bauer disk diffusion method. Whole genome sequencing was conducted to analyze genotypes, antibiotic resistance genes, and molecular epidemiology.
Results
The primary finding was a 29.0% prevalence of ESBL-producing E. coli strains among the sampled pandas, n=100. All identified strains showed 100.0% resistance to multiple β-lactam antibiotics. The study also reported high carriage rates of mobile genetic elements and identified 10 sequence types through MLST.
Interpretation
The findings indicate a significant increase in the prevalence of ESBL-producing E. coli compared to previous reports. While the statistical significance of the resistance rates is clear, the clinical implications for giant pandas and potential interspecies transmission require further investigation. The study's limitations include its focus on a single population and the speculative nature of interspecies transmission.
Key findings
- 29.0% prevalence of ESBL-producing E. coli strains, n=100.
- 100.0% resistance to amoxicillin, ampicillin, cefazolin, cefuroxime, and cefotaxime.
- 120 different antibiotic resistance gene subtypes detected.
- 19 ESBL gene subtypes identified, with bla CTX-M-4 at 100.0% prevalence.
- 89.7% carriage rates of IS26 and intI1 mobile genetic elements.
- 10 sequence types identified, with ST132 as the founder.
Limitations
- single-site study at Chengdu Research Base of Giant Panda Breeding
- potential for interspecies transmission remains speculative
- no longitudinal data to assess changes over time
- limited generalizability to wild populations