ABSTRACT
Background and Purpose: Typhoid fever, a disease caused by Salmonella typhi, is still one of the most important infectious diseases across the world. Different methods such as biochemical and Elisa methods are used for detection of this bacterium, which produce false responses in addition to being time-consuming and expensive. Therefore, the present research was conducted to detect Salmonella typhi by PCR method which is rapid, inexpensive and specific
Materials and methods: In this descriptive study which was conducted via diagnostic method, polymerase chain reaction [PCR] assay was developed for detection of Salmonella typhi. This strain had formerly been confirmed by biochemical methods. For detection by PCR, one primer pair was designed, being specific to ViaB gene. The PCR product was digested by restricted enzyme. For specificity of assay, 6 different strains were used as control negative and for sensitivity of PCR reaction, serial dilution of bacteria was used
Results: The PCR product of Salmonella typhi was 530 bp which were then confirmed by digestion enzymes. In testing the specificity of the assay, Salmonella typhimorium, Shigella flexneri, E. coli, Clostridium botulinum, Staphylococcus aureus and Bacillus subtilis were used as negative control, and did not yield a PCR product. The sensitivity of this method was estimated to be about 50 CFU/ml
Conclusion: The results of this study suggest that detection of ViaB gene with PCR method can be used for diagnossis of Salmonella typhi in clinical samples as a rapid, inexpensive, specific and highly sensitive method
ABSTRACT
Background and Purpose: Increased spread of antibiotic resistance and treatment failure among Escherichia coli isolates, most common agent of urinary tract infection, can be related to the increasing prevalence of expanded spectrum beta-lactamases [ESBL] clinical isolates. The present study was conducted to examine the antimicrobial resistance of urinary isolates of E. coli in Mashad and to detect the ESBL producing strains among them
Methods and Materials: In this descriptive study, 109 isolated E. coli were identified using differential biochemical experiments, from urine samples of hospitalized patients in Mashad hospitals [Ghaem and 17-Shahrivar Hospitals]. The antibiotic susceptibility was examined by disc diffusion method according to Kirby-Bauer standards. Detection of ESBL producers were done by double disc method. Data were analyzed by Statistica software using Chi-square. Findings with p<0.05 were considered as significant differences
Results: It was observed that %55.05, %34.86, %21.10, %12.84, %2.75 and %1.83 of clinical isolates were resistant to cotrimoxazole, nalidixic acid, ciprofloxacin, gentamicin, polymyxin and nitrofurantoin respectively. The highest and the lowest resistance were against co-trimoxazole and imipenem respectively. Twenty two clinical isolates of E. coli had multi-drug resistance to ciprofloxacin, nalidixic acid and co-trimoxazole. Double disc test was positive for 35 [32.11%] of 109 isolated E. coli bacteria and a high rate of associated resistance to cotrimoxazole, quinolones, gentamicin and polymyxin was found in ESBL producers [p<0.05]
Conclusion: As the results of the study indicated, ESBL producers have high prevalence among the E. coli isolates in this population