High prevalence of class 1 integrons in clinical isolates of methicillin‑resistant Staphylococcus aureus from India.

Introduction: Class1 integrons are one of the prevalent mechanisms of antibiotic resistance gene transfer in Gram‑negative organisms, but their prevalence and role in the spread of antibiotic resistance genes in methicillin‑resistant Staphylococcus aureus (MRSA) is unexplored. The purpose of this study was to investigate the prevalence of class 1 integrons in clinical isolates of MRSA. Materials and Methods: Total 143 MRSA isolates obtained from two different cities in India (Pune and Mumbai) were characterized by biochemical tests, and the antibiotic sensitivity was performed using the Clinical and Laboratory Standards Institute (CLSI) guidelines. The presence of class 1 integrons, sul1/qacEΔ1 region of class 1 integron and mecA gene among these isolates was determined by polymerase chain reaction (PCR). Results: All 143 isolates were mecA positive and coagulase‑positive. Overall, 71% of the MRSA isolates carried class 1 integrons; 58% (45/77) of the isolates obtained from Mumbai and 85% (56/66) of the isolates from Pune carried class 1 integrons. In all, 39% of these isolates carried sul1/qacEΔ1 region, thus confirming the association of class 1 integrons with antibiotic resistance genes. Along with ‑lactam antibiotics the MRSA isolates were resistant to several other antibiotics, with resistance to erythromycin, ciprofloxacin and trimethoprim‑sulfamethoxazole being observed in 75%, 66% and 60% of the isolates, respectively. Conclusion: To the best of our knowledge, this is the first report of class 1 integrons in MRSA isolates from India. The study provides insights into the prevalence of a novel mechanism adapted by MRSA for the propagation of antibiotic resistance genes.

Study of coagulase positive and negative Staphylococci in clinical samples.

A total of 983 patients samples (pus, urine, sputum, throat swabs, blood culture, CSF, vaginal swabs, ear swabs) were studied for a period of one year. The incidence of coagulase positive Staphylococci was highest in pus and the incidence of coagulase negative Staphylococci was highest in conjunctival swabs. Antibiotic Sensitivity pattern of routinely used antibiotics was studied. Coagulase positive Staphylococci was found to be most sensitive to Ciprofloxacin followed by Norfloxacin and Gentamycin. Coagulase negative Staphylococci showed maximum sensitivity to Ciprofloxacin followed by Norfloxacin and Chloramphenicol.

Characterization of MboI repeat DNA sequence of Anopheles stephensi.

MboI repeat fragment of mosquito Anopheles stephensi has been isolated by molecular cloning. The restriction map and entire nucleotide sequence of the 433bp insert has been determined. Hybridization of this repeat DNA with restriction enzyme digest of mosquito DNA does not show an interspersed pattern but suggests that this repeat may be tandemly repeated at one major site and a few minor sites in the genome of Anopheles stephensi. The hybridization pattern also indicates that this repeat family comprises of many similar but non-identical sequences. An open reading frame encoding 66 amino acids with an initiation and two tandem termination codons has been identified. This putative 66 amino acid polypeptide sequence has significant homology to a small region of RNA tumour viral envelope protein.