Isolation, identification and biological characteristics of a Proteus mirabilis from chicken

Abstract:

[Background] Proteus mirabilis (PM) is a zoonotic pathogen, which is widely distributed in environment. In recent years, diseases caused by PM and the drug tolerance to PM has gradually increased, raising the importance on the prevention and control of PM. [Objective] To isolate and identify PM from chicken, and to analyze its biological characteristics, such as drug resistance, pathogenicity, and biofilm formation ability. [Methods] Polymerase chain reaction (PCR) was used to identify 52 clinical PM strains which were isolated from sick chicken between 2019 and 2020. The drug resistance, virulence genes and biofilm formation of the clinical strains on PM were investigated by the drug-resistance phenotype, PCR, crystal violet staining method respectively. [Results] The results of 16S rRNA gene sequencing on 14 selected representative strains indicated that all the detected strains were PM. All isolates were resistant to clindamycin (CLDM), azithromycin (AZI), erythromycin (EM), tetracycline (TET) and rifampin (RFP), and the resistance rates of drugs other than chloramphenicol and ceftriaxone was higher than 50%. The results of detection of 13 virulence genes showed that all PM strains contained hpmA, hpmB, rpoA, mrpA, fliL, zapA, ureC, atfC, atfA and pmfA, while the detectable rates of ucaA, rsbA and hlyA were 19.23% (10/52), 48.08% (25/52) and 0.0% (0/52), respectively. The results of biofilm formation ability showed that all strains could form biofilm. 19.23% (10/52) of the isolates had strong ability of biofilm formation and the 25℃ temperature condition had stronger ability of biofilm formation than at 37℃. [Conclusion] PM from avian harbored various virulence genes, and had strong biofilm formation ability. The drug resistance to PM has increased significantly and resistance patterns were complex. It suggested that the tighter monitor on pathogenicity and drug resistance of PM should be carried out to reduce the risk of PM infection.