Isolation,identification,and drug resistance analysis of Providencia rettgeri Liaoning strain from swine
You Ying
Liu Liying
Zhou Dayong
Sun Yiya
Ren Zhenkun
Wang Huinuan
Gao Shenyang
Zhou Tiezhong
Abstract：This study aimed to investigate the pathogenicity and drug resistance of Providencia rettgeri isolated from pigs in Liaoning Province.Tissue samples(liver,intestine)were aseptically collected from diseased piglets on a farm in Yingkou City,Liaoning.Pathogen identification was performed using bacterial isolation/culture and molecular biology techniques,followed by mouse pathogenicity assays and antimicrobial susceptibility testing.Results showed that a strain of Providencia rettgeri was successfully isolated.Colonies appeared gray-white,moist,convex,and medium-sized on 10%sheep blood agar without hemolysis.Gram staining revealed Gram-negative short bacilli with rounded ends.Inoculation caused 100%morbidity and 50%mortality in mice,inducing pathological damage in multiple organs(liver,lungs,intestine),confirming strong pathogenicity.The isolate was sensitive to five antimicrobials:Ceftriaxone,amikacin,ciprofloxacin,norfloxacin,and levofloxacin,intermediate to cefoperazone and gentamicin,and resistant to ten others(including ampicillin,cefazolin,and ceftazidime).The study reveals that the Providencia rettgeri isolated from pigs in Liaoning Province has developed resistance to most antimicrobial agents.However,it remains highly susceptible to five antimicrobials:ceftriaxone(no approved veterinary formulation),amikacin,norfloxacin,and levofloxacin(internationally banned for veterinary use),leaving only ciprofloxacin as a clinically applicable veterinary drug for prevention and treatment.These findings provide valuable references for developing control strategies against Providencia rettgeri infections in swine.
Keywords：SwineProvidencia rettgeriIsolation and identificationPathogenicityDrug resistanceLiaoning strain
Publication Date：2025-07-15
Online Publishing Date：2025-08-22(First online date of this platform, not the publication date of the document)
Pages：6( 11-16 )