• Numan Javed
  • Nadeem Afzal
  • Romeeza Tahir
  • Afia Abbas


Background: Staphylococcus aureus is a gram positive bacterium that causes a number of diseasessuch as abscesses, infective endocarditis, septic arthritis, etc. It is acquiring resistance against manyantibiotics like methicillin; therefore its control is becoming increasingly difficult. Peripheral bloodphagocytes particularly polymorphonuclear leucocytes play an important role in the protectivemechanisms against these organisms. Phagocytes interact with bacteria and phagocytose thesemicroorganisms to kill them. Methods: Phenotypically different isolates of Staphylococcus aureusincluding methicillin resistant Staphylococcus aureus (MRSA) and methicillin sensitiveStaphylococcus aureus (MSSA) were collected from various hospitals of Lahore, Pakistan. Freshpolymorphonuclaer leucocytes were obtained from healthy individuals by centrifugation using FicolHypaque gradient combined with dextran sedimentation. Microbiological method was used for thedetermination of phagocytic index of phenotypic variants of Staphylococcus aureus. Results: Asignificant difference was observed between the phagocytic index of both bacterial groups. MSSAgroup showed the Mean±SD of 79.46%±3.9 while MRSA group showed 72.35%±2.5. Conclusion:Significant difference in phagocytic index indicates that it can be one of the mechanisms of MRSAto evade host immune system as compare to MSSA.Keywords: MRSA, MSSA, Phagocytic index, Polymorphonuclear leucocytes


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