双阳地区梅花鹿呼吸道源主要致病菌的分离鉴定及耐药性分析OA

[Objective]This experiment aimed to investigate the major pathogenic bacteria species causing respiratory diseases in sika deer in Shuangyang area of Jilin province,analyze the drug resistance characteristics,the distribution of virulence genes and pathogenicity,in order to provide references for rational clinical medication and scientific prevention and control.[Method]Tracheal secretions and lung tissue samples from diseased sika deer were collected.Bacterial species were identified through bacterial isolation and culture,Gram staining microscopy,and 16S rRNA sequencing.The susceptibility of the strains to 30 antimicrobial agents was tested using disk diffusion method.Virulence genes were detected by PCR amplification.Representative strains were selected to infect mice via intraperitoneal injection,and pathological changes in lung tissues were observed.[Result]A total of 76 isolates were obtained from the respiratory tract samples of diseased sika deer.Based on the colony morphology,they were preliminarily identified as 3 types,and all were identified as Gram-negative bacilli.Among them,the first strain formed pink colonies on MacConkey agar,appeared as short bacilli under microscopy,and was identified as Escherichia coli(26 strains,34.2%).The second strain formed colorless colonies on MacConkey agar,appeared as slender rods under microscopy,and was identified as Proteus mirabilis(32 strains,42.1%).The third strain appeared as short,thick bacilli under microscopy and was identified as Acinetobacter baumannii(18 strains,23.7%).Antimicrobial susceptibility testing results showed that Proteus mirabilis and Escherichia coli isolates were sensitive to imipenem(sensitivity rates was 95%and 90%,respectively)and quinolones(ciprofloxacin,sensitivity rate was 75%).Acinetobacter baumannii isolates were sensitive to amikacin(sensitivity rate was 60%)and imipenem(sensitivity rate was 50%).All 3 isolated bacteria showed resistance to β-lactam antibiotics(with resistance rates ranging from 70%to 95%).Virulence gene detection revealed that Proteus mirabilis isolates carried genes such as ureC(87.5%)and hpmA(81.3%).Escherichia coli isolates carried genes such as fimH(84.6%)and hlyA(61.5%),and Acinetobacter baumannii isolates carried genes such as csuC(88.9%)and abaⅠ(83.3%).The pathogenicity test on mice showed that all 3 isolated strains could cause pulmonary interstitial congestion,inflammatory infiltration and damage to the alveolar structure in mice.[Conclusion]In this study,Proteus mirabilis,Escherichia coli,and Acinetobacter baumannii were isolated from sika deer suffering from respiratory diseases in Shuangyang area.The drug resistance and virulence gene distribution of the isolated bacteria were further investigated.Clinical treatment recommendations suggested that imipenem or quinolone antibiotics should be the preferred options.At the same time,the use of β-lactam should be strictly controlled to slow down the development of drug resistance.