Year: 2024
Type: article
Abstract: Campylobacter remains a leading cause of foodborne illness worldwide, with Campylobacter jejuni accounting for approximately 90% of campylobacteriosis cases and being associated with Guillain–Barré syndrome.1 Macrolides are clinically important antimicrobials used to treat human campylobacteriosis.2 However, the continual rise of macrolide resistance in Campylobacter poses a significant challenge. The rate of macrolide resistance in China is higher than in other countries.3 First reported in China, the emergence of erm(B) mediating macrolide resistance is a matter of concern.4 Clinical erm(B)+C. jejuni isolates have only been reported in Australia and the USA in recent studies.5,6 In the present study, erm(B) was described in a clinical isolate of C. jejuni from China for the first time, and WGS was used to analyse the highly resistant strain. Antimicrobial susceptibility testing of the C. jejuni SHCB21133 isolated from a pathogen surveillance programme of outpatients with diarrhoea in Shanghai, China, was conducted using the broth microdilution method and interpreted according to the National Antimicrobial Resistance Monitoring System (NARMS; www.cdc.gov/narms/antibiotics-tested.html). The isolate showed resistance to all selected antimicrobial agents (Table 1). Illumina MiSeq and MinION sequencing technologies were combined to obtain the complete genome, revealing a novel genetic environment of erm(B) located in the chromosome. MLST analysis showed that the isolate belongs to a new ST. The complete genome consists of a 1 699 677 bp chromosome and a 50 526 bp plasmid (accession no. CP150436-CP150437). The antimicrobial resistance determinants were predicted using Abricate and Resfinder, including aph(2′′)-If, aad9, aph(3′)-IIIa, catA13, blaOXA-465, lnu(C), tet(L), fexA, aadE, erm(B), tet(O) and gyrA T86I mutations, consistent with the highly antimicrobial-resistant phenotype of SHCB21133.7 The erm(B) gene is 738 bp long and exhibits 100% nucleotide identity with erm(B) in C. jejuni strain C179b (KF864551). The erm(B)-harbouring MDR genomic island (MDRGI) is 23 151 bp and has a GC content of 36.54%, higher than that in the genome, suggesting the MDRGI was exogenously acquired. The novel MDRGI, designated Type XII, is similar to a previously identified Type X MDRGI (MH257907), with a fexA-containing segment and transposases inserted (Figure 1).8 ISChh1 (CP015575) of the IS607 family has been described in C. hyointestinalis, indicating the transposable element can move between different locations across species.9 The inserted fexA-containing segment showed 99% identity with Campylobacter coli 1922C17 (MT663352) and C. jejuni plasmid pCJFEX (CP048762), indicating DNA exchange among Campylobacter spp.10 Comparative analysis of the C. jejuni SHCB21133 and previously identified C. jejuni 8C/36C, C. coli 1922C17 and C. jejuni plasmid pCJFEX. The erm(B) gene is in red, aminoglycoside resistance genes are in yellow, the fexA gene is shown in orange, transposable elements are in green, tetracycline resistance genes are in purple, genes with predicted functions are in grey, and genes encoding hypothetical proteins are in white. This figure appears in colour in the online version of JAC and in black and white in the print version of JAC. MICs for C. jejuni SHCB21133 in Shanghai aR indicates resistance. To our knowledge, this is the first description of an erm(B)+ clinical C. jejuni isolate within a novel genomic context in China. The associated genetic determinants and transposable elements could highlight the monitoring of its spread. This work was supported by Shanghai Sailing Program (21YF1439200) and Three-Year Initiative Plan for Strengthening Public Health System Construction in Shanghai (2023-2025) Key Discipline Project (GWVI-11.1-09). None to declare.
DOI: 10.1093/jac/dkae294
Authors: Fen Gao, Jiayuan Luo, Min Chen
Language: English
Subfield: Food Science
Domain: Life Sciences
Open Access status: hybrid
Estimated APC paid: $3,851
OpenAlex ID: W4402171128