Rapid detection of different serovares of Salmonella entrica by multiplex PCR

Typhoid fever is still one of the serious public health problems in many geographic areas and is endemic in most countries. Aim of current study was to evaluate a shortened time -Multiplex PCR for rapid detection of different Salmonella enterica serovars. The PCR primers for three target genes tyv.prt and invA were subjected for amplification by PCR. By using simple DNA extraction method, rapid PCR cycles and rapid electrophoresis procedure with simple and very cheap buffer were utilized in 200 to 300 volts for 15 minutes to separate the PCR products. The results showed that all reference and clinical isolates of S. enterica were accurately identified by this assay with no cross reaction with other enterobacterial strains tested. Detection limit of the reaction was to be fewer than 10[-1] colony forming unit. These data indicate that the optimized rapid cycle multiplex PCR is a potentially valuable tool for rapid diagnosis of S. enterica using a conventional thermal cycler. This method reduced the reaction time of PCR from 3.5 h to less than 1 h.

Advatages of rapid diagnosis of bacterial meningitis by PCR in compare with direct microscopy and culture

Acute bacterial meningitis has remained an important cause of death and neurological damages among survivors. Rapid diagnosis of bacterial meningitis is crucial for the early targeting of antimicrobial therapy. The aim of this study was to develop and apply a PCR assay for rapid diagnosis of meningitidis and to compare the results with those obtained by conventional bacteriology. We assessed 150 cerebrospinal fluid [CSF] specimens from suspected patients by PCR targeting 16S rRNA gene with specefic primers for Neisseria meningitidis, Sterptococcus pneumonia and Heamophilus influenza. All speciemns were also examined by conventional bacteriology. The rapidity of diagnosis increased when bacteriological methods were combined with PCR. Of 150 speciemens tested, 10 were positive for Neisseria meningitidis in PCR. Direct microscopy and bacterial culture found 5 and 8 cases infected with this organism respectively. PCR was more sensitive than direct microscopy and culture for detection of Neisseria meningitidis. However, direct microscopy may provide evidences for the quality of specimens and presence of other organisms in the samples. Wet- mount direct microscopy showed morphology and arrangements of the observed organisms that may be helpful in presumptive identification of certain bacteria such as gram negative bacilli and cocci. Moreover, the observed organisms may be useful in correct selection of culture media in the laboratory and prescription of appropriate therapy by physicians in a quickest time