Erythromycin resistance of clinical Campylobacter jejuni and Campylobacter coli in Shanghai, China

Abstract

<i>Campylobacter</i> species are zoonotic pathogens, as well as the prevalent cause of foodborne bacterial gastroenteritis. The spread of antimicrobial-resistant strains poses a serious threat to global public health and attracts attention worldwide, but information about clinical <i>Campylobacter</i> is relatively limited compared to isolates from food and animals. The current study illustrated the prevalence and antimicrobial resistance profiles of <i>Campylobacter jejuni</i> and <i>Campylobacter coli</i> isolates collected from a consecutive surveillance program between 2012 and 2019 in Shanghai, China, using antimicrobial susceptibility testing and whole-genome sequencing. Among the 891 <i>Campylobacter</i> strains (761 <i>C. jejuni</i> and 130 <i>C. coli</i>) isolates collected, high portions above 90% of resistance to ciprofloxacin, nalidixic acid, and tetracycline were observed for both <i>C. jejuni</i> and <i>C. coli</i>. The most common MDR profiles represented by <i>C. jejuni</i> and <i>C. coli</i> were combination of ciprofloxacin, tetracycline, florfenicol and nalidixic acid (5.39%), and azithromycin, ciprofloxacin, erythromycin, gentamicin, tetracycline, clindamycin, nalidixic acid (28.46%), respectively. The erythromycin resistance of <i>C. coli</i> (59.23%) is higher than <i>C. jejuni</i> (2.50%). A total of 76 erythromycin resistant isolates (16 <i>C. jejuni</i> and 60 <i>C. coli</i>) were sequenced using Illumina platform for determining the genotypes, antimicrobial resistance patterns and phylogeny analysis. Multilocus sequence typing (MLST) analysis showed a high genetic diversity with 47 sequence types (STs), including 4 novel alleles and 12 new STs. The most abundant clonal complexes (CCs) were CC-403 (31.25%) and CC-828 (88.33%) for <i>C. jejuni</i> and <i>C. coli</i>, respectively. Among the 76 erythromycin-resistant isolates, mutation A2075G in 23S rRNA and <i>erm</i>(B) gene were detected in 53.95 and 39.47%, respectively. The <i>erm</i>(B) gene was identified exclusively in 30 <i>C. coli</i> isolates. All these <i>erm</i>(B) positive isolates were multi-drug resistant. Furthermore, comparison of the <i>erm</i>(B)-carrying isolates of multiple sources worldwide demonstrated the possibility of zoonotic transmission of <i>erm</i>(B) in <i>Campylobacter</i>. These findings highlight the importance of continuous surveillance of erythromycin resistance dissemination in <i>Campylobacter</i> which may compromise the effectiveness of antimicrobial therapy.