Isolation, identification of goose Proteus mirabilis and it’s virulence genes detection

Abstract:

[Background] Proteus mirabilis is a Gram-negative and pleomorphic facultative anaerobe, and it is an opportunistic pathogen of zoonosis. [Objective] To confirm the pathogeny that causes goslings’ death at some geese farm in Tongliao, Inner Mongolia Autonomous Region, and characterize the virulence genes of the pathogenic bacteria. [Methods] The pathogenic bacteria were confirmed based on the pathogens screening and artificial challenge experiment, and identified according to 16S rRNA genes sequence and biochemical characteristics. Primers of 8 virulence genes (ureC, zapA, mrpA, ucaA, rsbA, pmfA, atfA, atfC) were designed according to the sequences of Proteus mirabilis reported on the GenBank and used to detect the virulence genes of the pathogenic bacteria by PCR amplification. [Results] The pathogenic bacteria isolated from infected gosling was proved to be the pathogeny to Proteus mirabilis. Analysis of 16S rRNA gene sequences of the AYQ-1 gave highest identity (99%) to P. mirabilis and named AYQ-1. This was further supported by phylogenetic tree and biochemical characteristics, AYQ-1 was identified as P. mirabilis. AYQ-1 gave positive PCR results for 8 virulence genes. Intraperitoneal injection with AYQ-1 could lead to goslings’ death, with a value of the median lethal dose (LD50) of 1.51×107 CFU/mL. Antibiotics sensitivity test showed that among 19 antibiotics tested, AYQ-1 was sensitive to 19 antibiotics such as streptomycin, aztreonam and ofloxacin, but it was resistant to 15 antibiotics such as vancomycin, penicillin and achromycin. [Conclusion] The pathogen was identified to be Proteus mirabilis, and it’s virulence genotype are ureC(+), zapA(+), mrpA(+), ucaA(+), rsbA(+), pmfA(+), atfA(+), atfC(+).