Rapid Molecular Approach for Simultaneous Detection of Salmonella spp., Shigella spp., and Vibrio cholera

AbstractObjectivesGastrointestinal tract infection is still one of the serious public health problems in many geographic areas and is endemic in most countries including Iran. Early detection of the gastrointestinal tract pathogens can be extremely important. The aim of the current study was to apply a shortened time-multiplex polymerase chain reaction (PCR) for rapid and simultaneous detection of Salmonella spp., Shigella spp., and Vibrio cholera.MethodsThe standard and clinical strains of Salmonella spp., Shigella spp., and V. cholerae were used in the assay. Multiplex PCR was performed and optimized based on amplification of invA, putative integrase, and ompW genes for detecting Salmonella spp., Shigella spp., and V. cholerae, respectively. The specificity of the assay was evaluated by testing 12 different bacterial species.ResultsOnly Salmonella spp., Shigella spp., and V. cholerae strains had positive results when subjected to the assay using multiplex PCR. The assay showed a high sensitivity, and no amplification products were observed in multiplex PCR with any of the other microorganisms.ConclusionOur study indicated that the invA, putative integrase, and ompW-based multiplex PCR assay appears to be an efficient method for rapid and simultaneous detection of Salmonella spp., Shigella spp., and V. cholerae

Class 1 integron-mediated antibiotic resistance in Salmonella enterica strains isolated in Tehran, Iran

Background and objectives: Salmonellae infection is one of the most important foodborne diseases. Antimicrobial drug resistance is increasing among Salmonella spp. and causes significant therapeutic problems in the treatment of diseases caused by this organisms. The aim of this study was to investigate the prevalence of class 1 integrons in Salmonella enterica and their relationship with antimicrobial resistance in clinical isolates from Iran during 2007-2009. Materials and Methods: Salmonella spp. strains were isolated from several hospitals in Tehran, Iran. The isolates were identified by standard biochemical tests and agglutination using specific antisera. The susceptibility of the isolates was determined according to the CLSI guidelines. Class 1 integrons were detected by PCR. Statistical comparisons of the frequency of resistance between integron-positive and integron-negative were made using Pearson χ2 test or the Fisher’s exact test. A P≤0.05 was intended as the level of statistical significance. Results: Class 1 integrons were detected in 39.1% of the strains. Integron-positive isolates represented seven different Salmonella enterica serotypes. All Salmonella isolates carrying class 1 integrons showed multiple drug resistance. Conclusion: Our findings showed that integrons class 1 were widely distributed among Salmonella enterica isolates. Surveillance and monitoring of antimicrobial drug resistance, including screening for integrons as likely indicators of drug resistance and acquisition of new resistance traits, are necessary steps in planning effective strategies for containing this phenomenon within foodborne infection organisms

Use of TaqMan® real-time PCR for rapid detection of Salmonella enterica serovar Typhi

We evaluated the performances of a newly designed real-time polymerase chain reaction (PCR) assay using TaqMan® probes to detect Salmonella Typhi. TaqMan® real-time PCR assays were performed by designed primers and probe based on the staG gene for detecting S. Typhi. The specificity of the assay was evaluated on 15 Salmonella serovars. The analytical specificity was evaluated on 20 non-Salmonella microorganisms. The analytical sensitivity was assessed using decreasing DNA quantities of S. Typhi ATCC 19430. Finally the detection capability of the TaqMan® real-time PCR assay on isolates recovered from patients with Salmonella infections was compared to the conventional PCR assay. Only S. Typhi strain had positive results when subjected to the assay using Typhi-specific real-time PCR. No amplification products were observed in real-time PCR with any of the non-Salmonella microorganisms tested. The TaqMan® real-time PCR was more sensitive than the conventional PCR. In conclusion, we found that the easy-to-use real-time PCR assays were faster than conventional PCR systems. The staG-based TaqMan® real-time PCR assay showed to be specific and sensitive method for the safe and rapid detection of the S. Typhi

Characterization of the first extended-spectrum b-lactamase–producing nontyphoidal Salmonella strains Isolated in Tehran, Iran

The infections caused by Salmonella remain a significant public health problem throughout the world. b-Lactams and fluoroquinolones are generally used to treat invasive Salmonella infections, but emergence and spread of antibiotic-resistant strains are being increasingly notified in many countries. In particular, detection of extended spectrum b-lactamases (ESBLs) in Salmonella spp. is a newly emerging threat worldwide. This study was carried out to characterize b-lactamase–producing Salmonella strains identified in Tehran, Iran. Over the 2-year period from 2007 to 2008, 6 of 136 Salmonella isolates recovered from pediatrics patients, including three Salmonella enterica serotypes Enteritidis (S. Enteritidis) and three S. Infantis, showed an ESBL-positive phenotype. Polymerase chain reaction and sequencing were used to identify the genetic determinants responsible for ESBL phenotypes. The Salmonella isolates were also compared by pulsed-field gel electrophoresis. All ESBL-producing strains, but one, carried the blaCTX-M-15 gene. Moreover, three of four strains that proved to be positive for a blaTEM gene were producing a TEM-1 b-lactamase. Two strains of S. Infantis tested positive for a previously unidentified CTX-M and TEM ESBL, respectively. All ESBL-producing strains carried the insertion sequence ISEcp1 gene. Except for one strain of serotype Infantis, all strains were able to transfer the ESBL determinants by conjugation. Distinct, but closely related, pulsed-field gel electrophoresis patterns were observed among the strains belonging to both serotypes. This study reports for the first time the emergence and characterization of ESBL-producing S. Enteritidis and Infantis strains in Iran

Aspects of urinary tract infections and antimicrobial resistance in hospitalized urology patients in Asia: 10-Year results of the Global Prevalence Study of Infections in Urology (GPIU)

10.1016/j.jiac.2017.11.013Journal of Infection and Chemotherapy244278-283JICH