Phylogenetic characteristics, virulence and antibiotic resistance of Aeromonas caviae isolated from foodborne and environmental samples
10.3760/cma.j.cn112309-20190924-00307
- VernacularTitle:食品与环境中豚鼠气单胞菌系统发育分析以及毒力和耐药性研究
- Author:
Fanxu KONG
1
;
Min HAO
;
Hengwei WANG
;
Tian TIAN
;
Xifeng SHAO
;
Yanyan SONG
Author Information
1. 内蒙古科技大学包头医学院 公共卫生学院 014040；北京市朝阳区疾病预防控制中心 100021
- From:
Chinese Journal of Microbiology and Immunology
2020;40(2):91-97
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To identify 49 Aeromonas caviae strains isolated form foodborne and environmental samples and analyze their virulence and antibiotic resistance. Methods:All strains were identified by VITEK and API 20NE. Two housekeeping genes, gryB and rpoD, were amplified by PCR for phylogenetic analysis. Virulence genes including act, alt, ast, lip, ahp, aerA, hlyA, ompA1 and fla were detected by PCR. In vitro antimicrobial susceptibility of these strains was tested with AST-GN16 kit. Results:Fifty-four Aeromonas caviae/ Aeromonas hydrophila strains were identified by biochemical tests. Phylogenetic analysis revealed that there were 49 Aeromonas caviae strains, four Aeromonas hydrophila strains and one Aeromonas taiwanensis strain. The positive rates of alt, lip, ompA1, fla, act, aerA and hlyA genes were 100.00%, 100.00%, 79.59%, 14.29%, 2.04%, 2.04% and 2.04%, respectively. None of the isolates carried ast or ahp gene. A total of four virulence gene combination patterns were detected, and the predominant pattern was alt/ lip/ ompA1 (32/49). Antibiotic resistance rates of the Aeromonas caviae strains to ampicillin, cefazolin, cefoxitin, amoxicillin/clavulanic acid, ceftriaxone, trimethoprim/sulfamet hoxoazole and aztreonam were 79.59%, 14.29%, 10.20%, 6.12%, 4.08%, 4.08% and 2.04%, respectively. All strains were susceptible to piparacillin/tazobactam, imipenem, amikacin, gentamicin, levofloxacin, tigacycline and nitrofurantoin. Two multidrug-resistant strains were detected. Conclusions:Aeromonas caviae/ Aeromonas hydrophila can be effectively identified by the housekeeping genes gyrB and rpoD, and the closely related Aeromonas caviae and Aeromonas taiwanensis strains can be identified by rpoD. All Aeromonas caviae strains carried two or more virulence genes and one strain isolated from environment was positive for seven virulence genes. Aeromonas caviae strains were generally resistant to penicillin, which was mainly relate to the production of β-lactamase. No strain was resistant to carbapenems, aminoglycosides, fluoroquinolones, tetracyclines or furans. Multidrug-resistant strains were observed in food and drinking water.
