AUTHOR=Li Mingxi , Lv Ruiqing , Li Xiaowei , Song Chao , Xingxin Liang , Zhang Huanrong 

TITLE=Antimicrobial resistance, serogroups, virulence gene profiles and MLST of Escherichia coli from giant panda

JOURNAL=Frontiers in Microbiology

VOLUME=14

YEAR=2024

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2023.1236227

DOI=10.3389/fmicb.2023.1236227

ISSN=1664-302X

ABSTRACT=<p><italic>Escherichia coli</italic> is a major bacterial pathogen which causes diarrhea in the giant panda. This study investigated the biological characteristics of 100 <italic>E. coli</italic> strains isolated from fecal samples collected from 100 captive giant pandas of different age groups and sexes. A standard Kirby-Bauer disk diffusion antimicrobial susceptibility test was performed with the isolates and we then further evaluated the antibiotic resistance genes (ARGs) by high-throughput quantitative PCR. Additionally, we then analyzed O serogroups through a slide agglutination test, virulence genes and the multi-locus sequence typing (MLST) by PCR. Antimicrobial susceptibility testing demonstrated that the 100 <italic>E. coli</italic> strains were mainly resistant to ENR (68%), AM (56%), IPM (55%), AMX (54%) and CA (52%), but were susceptible to MEM and FOX. The resistance to TZP, AK, FEP, CAZ, AMS, AZM, AT and IPM was significantly related to age (<italic>p</italic> &lt; 0.05); the resistance rate of <italic>E. coli</italic> isolated from female giant pandas to N was significantly higher than in males (<italic>p</italic> &lt; 0.05). Forty-five different types of ARGs were found, which included a total of 2,258 ARGs, in the 100 <italic>E. coli</italic> isolates. The top 10 of detection rate of ARGs were: <italic>acrA-04</italic>, <italic>acrA-05</italic>, <italic>aacC</italic>, <italic>bla<sub>CTX-M-04</sub></italic>, <italic>ampC-04</italic>, <italic>bla<sub>SHV-01</sub></italic>, <italic>bla<sub>TEM</sub></italic>, <italic>sul2</italic>, <italic>bla<sub>OXY</sub></italic>, <italic>tetA-02</italic>. ARGs <italic>aac (6’)I1</italic>, <italic>blaCTX-M-03</italic>, <italic>tetD-02</italic>, <italic>blaSHV-02</italic> and <italic>blaOXY</italic> were significantly related to age (<italic>p</italic> &lt; 0.05), <italic>blaSHV-02</italic>, <italic>blaNDM</italic> and <italic>ampC-04</italic> were related to sex (<italic>p</italic> &lt; 0.05). Twelve different O serogroups from 32 <italic>E. coli</italic> isolates were distinguished, including O4, O8, O9, O15, O18, O20, O55, O88, O112, O157, O158, and O167. The most prevalent O serotype was O20, but O28, O45, O101, O149, and O152 were not detected. Fourteen different types of virulence genes were detected in the 100 <italic>E. coli</italic> isolates, of which <italic>papA</italic> (99%) were highly detected, while <italic>hlyA, elt</italic> and <italic>estA</italic> were not detected. MLST showed that 41 STs, which had one CCs and six groups with SLVs, in the 100 <italic>E. coli</italic> strains were identified, the main type was ST37. Our results advocate the need of strict biosecurity and surveillance programs in order to prevent the spread of pathogenic bacteria in the captive giant panda population.</p>