ABSTRACT
Plasmid profile analysis and antibiotic resistance pattern determination were carried out for 117 phage untypable S. Typhimurium strains. Majority of the strains (82%) were resistant to all the seven antibiotics tested, R-pattern being ApCmKmSmSuTcTp, rest (12%) showed heterogenous R-patterns. Plasmid DNA analysis revealed phage untypable strains to harbour large (58.8-114.3 MDal), intermediate size (36 MDal, 42 MDal) and small (1.8-5.2 MDal) plasmids with varying molecular weights. All the phage untypable strains could be subgrouped by plasmid profile analysis into 23 plasmid patterns. Plasmid profile analysis could discriminate large number of phage untypable strains on the basis of their plasmid pattern.
Subject(s)
Anti-Bacterial Agents/pharmacology , Bacteriophage Typing , Drug Resistance, Microbial , Humans , India , Plasmids , Salmonella typhimurium/classificationABSTRACT
Adhesive and invasive properties were compared with plasmid profile in S. Typhimurium strains of phage type 99(10) and 36(10). All strains of phage type 99 were multiple drug resistant (ApCmKmSmSuTcTp) and harboured small plasmids of 2.4-5.2 MDal. Six strains of the phage type 36 had ApCmTc R-pattern and two with only ampicillin resistance, carried plasmids of molecular size 2.6-5.2 MDal; two strains were sensitive to all antibiotics and devoid of plasmids. None of the strains were found to harbour high molecular weight plasmids. All plasmid positive strains of phage types 99 and 36 could be divided into two groups of three plasmid patterns each, which were phage type specific. All plasmid positive and negative strains adhered and invaded HeLa cells to different degrees. No correlation could be established between plasmid profile and adhesion invasion characteristics. High molecular weight plasmids therefore are unlikely to be essential for adhesion and invasion.