Rapid screening of pyogenic Staphylococcus aureus for confirmation of genus and species, methicillin resistance and virulence factors by using two novel multiplex PCR

Objectives: Emergence of methicillin resistant Staphylococcus aureus [MRSA] is a major medical problem of current era. These bacteria are resistant to most drugs and rapid diagnosis can provide a clear guideline to clinicians. They possess specific virulence factors and relevant information can be very useful. We designed this study to develop multiplex PCRs to provide rapid information

Methods: We studied 60 Staphylococcus aureus isolates and detected methicillin resistance by cefoxitin sensitivity and targeting of mecA gene. After initial studies with uniplex PCRs we optimized two multiplex PCRs with highly reproducible results. The first multiplex PCR was developed to confirm genus, species and methicillin resistance simultaneously, and the second multiplex PCR was for screening of virulence factors

Results: We found 38.33% isolates as methicillin resistant, a-toxin, the major cytotoxic factor, was detected in 40% whereas 6-hemolysin was found in 25% cases. Panton Valentine leucocidin was detected in 8.33% and toxic shock syndrome toxin in5% cases. The results of uniplex and multiplex PCRs were highly compatible

Conclusions: These two multiplex PCRs when run simultaneously can provide vital information about methicillin resistance and virulence status of the isolate within a few hours as compared to several days needed by routine procedures

Report of a recurrent mutation in ARS [component B] gene with severe Mal de Meleda in a large consanguineous Pakistani family

To characterize the disease causing mutation in a large consanguineous Pakistani family with severe Mal de Meleda [MDM] or keratosis palmoplantaris transgrediens, a rare autosomal recessive skin disorder. Single nucleotide polymorphism [SNPs] genotyping was performed using the GeneChip Mapping 250K array [Affymetrix]. Homozygosity mapping and sorting of genomic regions were performed with dedicated software called AutoSNPa. Selected regions were further investigated by genotyping with microsatellite markers derived from known and novel polymorphic repeats. Two-point LOD score calculation was performed by using the MLINK of Fastlink computer package. All three coding exons of ARS [component B] gene were amplified by PCR and sequenced. Sequencing of all the coding exons of ARS [component B] gene in the affected individuals revealed a recurrent missense mutation in exon 3 at base pair 256 from Guanine to Alanine [256G>A] and as a result the amino acid Glycine is replaced by Arginine at position 86 [G86R]. This finding will facilitate control of affected MDM births in the Pakistani families