Association among biofilm formation, virulence gene expression, and antibiotic resistance in Proteus mirabilis isolates from diarrhetic animals in Northeast China

Yadong Sun,Lili Zhao,Qiqi Xia,Junwei Ge,Hongbin Wang,Yue Pan,Shanshan Wen,Hongyan Chen,Hanghang Liu,Chengwei Wei

doi:10.1186/s12917-020-02372-w

Abstract

BackgroundThe aim of this study was to investigate the association among biofilm formation, virulence gene expression, and antibiotic resistance in P. mirabilis isolates collected from diarrhetic animals (n = 176) in northeast China between September 2014 and October 2016.ResultsApproximately 92.05% of the isolates were biofilm producers, whereas 7.95% of the isolates were non-producers. The prevalence of virulence genes in the biofilm producer group was significantly higher than that in the non-producer group. Biofilm production was significantly associated with the expression of ureC, zapA, rsmA, hmpA, mrpA, atfA, and pmfA (P < 0.05). The results of drug susceptibility tests revealed that approximately 76.7% of the isolates were multidrug-resistant (MDR) and extensively drug-resistant (XDR). Biofilm production was significantly associated with resistance to doxycycline, tetracycline, sulfamethoxazole, kanamycin, and cephalothin (P < 0.05). Although the pathogenicity of the biofilm producers was stronger than that of the non-producers, the biofilm-forming ability of the isolates was not significantly associated with morbidity and mortality in mice (P > 0.05).ConclusionOur findings suggested that a high level of multidrug resistance in P. mirabilis isolates obtained from diarrhetic animals in northeast China. The results of this study indicated that the positive rates of the genes expressed by biofilm-producing P. mirabilis isolates were significantly higher than those expressed by non-producing isolates.

Highlights

The aim of this study was to investigate the association among biofilm formation, virulence gene expression, and antibiotic resistance in P. mirabilis isolates collected from diarrhetic animals (n = 176) in northeast China between September 2014 and October 2016
Biofilm production was significantly associated with the expression of Urease C (ureC), zapA, rsmA, hmpA, mannose-resistant Proteus-like fimbriae (mrpA), atfA, and P. mirabilis fimbriae (pmfA) (P < 0.05)
We found that the biofilm-forming ability of the P. mirabilis isolates was significantly associated with the resistance to doxycycline, tetracycline, sulfamethoxazole, kanamycin, and cephalothin (P < 0.05). β-lactamase has been reported to decrease the ability of E. coli to form biofilms by inhibiting peptidoglycans, which are required for the assembly of surface molecules on the biofilm

Summary

Introduction

The aim of this study was to investigate the association among biofilm formation, virulence gene expression, and antibiotic resistance in P. mirabilis isolates collected from diarrhetic animals (n = 176) in northeast China between September 2014 and October 2016. Proteus mirabilis is a motile gram-negative bacillus belonging to the family Enterobacteriaceae It is an opportunistic pathogen of great importance that is found in water and soil as well as in the intestinal tracts of mammals. It has been recognized as a leading cause of urinary tract infections [1] and the primary infectious factor. The association between biofilm formation and various virulence factors in P. mirabilis isolates from diarrhetic animals is still unknown

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