The prevalence of the methicillin resistant staphylococcus Aureus in the postoperative wound infection in a South Indian hospital

Introduction: Objectives of the present study was to find the prevalence of methicillin resistant staphylococcus aureus at a South Indian hospital. Methods: Hundred clinically suspected cases of infected postoperative wounds were subjected to culture and sensitivity. All the S.aureus isolates were screened for MRSA. Results: Prevalence of MRSA was 62.5%. All the MRSA strains showed multidrug resistance except to Vancomycin and Cloxacillin. Conclusion: Judicious use of antibiotics, strict asepsis and proper hygiene should be strictly applied to reduce postoperative wound infections. The determination of prevalence and antimicrobial profile of MRSA will help the clinician while treating.


Introduction
Staphylococcus aureus has been reported as a major cause of community and hospital acquired infections [1][2][3]. The organism has a differential ability to spread and cause outbreaks in hospitals [4]. Ever since its first Cost of treatment is another major problem faced by patients in the developing countries [5].
Despite the advances made in asepsis, antimicrobial drugs, sterilization and operation techniques, postoperative wound infections continues to be a major problem in all the branches of surgery in the hospitals and are responsible for the increasing cost, morbidity and mortality related to surgical operations.
Recent increase of methicillin resistant and multiple drug resistant strains at large hospitals has started to pose great difficulty in selecting antimicrobial agents [6]. Isolation of the organism and antimicrobial profile helps in the prompt management of postoperative

Materials and Methods
The present study was performed at the microbiology department of our institution.The present study included a total of 100 cases of postoperative wound infection. On day 2, identification of the growth was performed and the morphology of the colonies on the blood agar and McConkey agar were studied. Smear from the colonies were prepared and stained with gram stain and segregated into gram positive and negative after the microscopic examination. The bacteria were further microbiologically segregated by using the relevant biochemical and physiological tests [8,9].
The antibiotic susceptibility was studied by using the

Results
In the 100 cases of the present study, about 111 bacteria were observed accounting for 1.1 bacteria per case as an average. All these 111 isolates were aerobes and facultative anaerobes. The grams stain of all direct smears correlated well with the growth on culture. Of these 111 isolates, 36 (32.4%) were gram positive cocci and 75 (67.6%) were gram negative bacilli. E. coli was isolated most frequently (24.3%) followed by S. aureus (21.6%), Pseudomonas spp (20.7%), Klebsiellaspp (13.5%) and Coagulase negative Staphylococci (7.2%).
The patterns of bacteria isolated in the present study group are represented in Figure 1. Out of the 100 clinical samples, 85 samples (85%) yielded growth of single bacterium (monomicrobial/pure growth), 13 samples (13%) yielded growth of more than one bacterium (polymicrobial/mixture) and 2 samples (2%) yielded no growth. Staphylococcus Aureus was the most common bacteria (91.7%) isolated in pure culture, which is followed by Pseudomonas sp (82.6%).
Enterococcus spp and Proteus spp were isolated equally in both pure growth and mixtures, while Citrobacterspp and Enterobacterspp both were isolated only in mixed cultures (50% each). The bacterial isolates in pure growth and mixtures in post-operative wound infection of the present study are represented in Table 1.        The lowered PO 2 inhibits the phagocytosis and will enhance the growth of anaerobic microorganisms [11].
For the most nosocomial wound infections, the endogenous flora of the patient which is present in the body surface and the visceramay become the source of infection [12].  [13]. It has been reported that the balance between the host immunity and bacterial virulence has been altereddue to the use of higher antibacterial agents [14].
In the present study, the gram negative bacillary   [16] where it was 76%.
The rapid emergence of S.aureus resistant to variety of antibiotics is of a great concern. The resistance to