Analysis of Antibiotic-induced Drug Resistance of Salmonella Enteritidis and Its Biofilm Formation Mechanism.

This research was to explore the antibiotic-induced drug resistance of Salmonella enteritidis and its biofilm formation mechanism. Kirby-Bauer (K-B) disk method recommended by Clinical and Laboratory Standards Institute (CLSI) was used to test the drug sensitivity of Salmonella enteritidis to 16 kinds of antibiotics including s-lactams, aminoglycosides, quinolones, sulfonamides, chloramphenicols, and tetracyclines. Polymerase chain reaction (PCR) was performed to detect the carrying of drug resistance genes of 29 kinds of antibiotics including s-lactams, aminoglycosides, quinolones, sulfonamides, chloramphenicols, and tetracyclines of Salmonella enteritidis. The expressions of esp, ebpA, ge1E, and fsrB genes in biofilm group and plankton group were detected when Salmonella was induced, and the difference of gene expression before and after induction was detected by FQ-PCR. The drug resistance rates of Salmonella enteritidis to nalidixic acid, ampicillin, streptomyces, and cefoperazone were high, which were 94.5%, 75%, 67%, and 52%, respectively. 94 strains of Salmonella enteritidis formed 22 kinds of drug resistance spectrum, the strains were generally resistant to 4-5 antibiotics, and some strains formed fixed drug resistance spectrum as follows: AMP-CFP-STR-NA-TE (22.6,21.7%), AMP-STR-NA-TE (17,16%), and AMP-CFP-STR-NA (11.1,10.6%). During biofilm formation, fsr can increase the expression of ge1E and decrease the expression of esp and ebpA. In summary, Salmonella enteritidis was generally resistant to nalidixic acid, ampicillin, and streptomycin, and the multidrug resistance was severe. The drug resistance genes sul2, sul3, blaTEM-1-like, tet(A), and tet(G) were highly carried in Salmonella enteritidis. In addition, esp, ebpA, ge1E, and fsrB genes were closely related to the biofilm formation of Salmonella enteritidis.