Characterization of Staphylococcus Spp. From Patients’ Sputum and Determination of Its Antibiotic Resistance/ Susceptibility

Abstract

Background: The occurrence of multi drug resistance is quite prevailing in the species of Staphylococcus aureus since a very long time. Due to this, it poses a threat as most of the antibiotics used against it are not effective due to multiple antibiotic-resistant mechanisms. Although there has been the development of new treatments and advancements in control of infections, but the persistence of resistance is still at a rise. Objective: In this paper, an effort is done to isolate a strain of Staphylococcus species from sputum to further analyse the organism’s capacity for antimicrobial resistance/sensitivity. Methodology: The isolation was done using sputum sample collected randomly from ten patients suffering from nosocomial infections (both male and females) of Kamti Healthcare and Diagnostics, Siliguri. Microbiological and microscopic techniques were used. The biochemical tests were performed, and Polymerase Chain Reaction (PCR) was done to characterize the species of the organism. To confirm the species, 16s ribosomal sequencing and phylogenetic analysis was performed. Antibiotic resistance test was performed using disk diffusion method to test the antibiotic resistance/ susceptibility of the organism. Statistical analysis of the zone of inhibition was done using ANOVA. Results: 10 isolates were obtained that were characterized as Gram positive and Catalase positive. The isolates 1, 2, 4, 6, 9 and 10 were positive to carbohydrate fermentation test and negative for citrate utilization and oxidase test. These isolates were confirmed as Staphylococcus aureus species as analysed from PCR test and previous studies. These isolates were found susceptible to some antibiotics while resistant to gentamycin, amoxyclav/augmentin, erythromycin, rifampicin, vancomycin, meropenem, levofloxacin and amoxycillin with p-value ≤ 0.05. Conclusion: The study confirms the isolated strain as Staph aureus, as no study has indicated the antibiotic susceptibility/ resistance to these antibiotics till present. The need of the hour is to identify other such strains so that certain preventive measures could be attained to treat the infections caused by such strains using alternative methods.