A study of effect of antibiotics after culture and sensitivity of surgical sites infection cases in a medical college

Abstract

Backround - The role of pre-operative antibiotics in wound sepsis is well established. The selection of drug, timing and duration of administration are very significant.Prolonged use of prophylactic antibiotics may lead to superinfection This study was conducted to find out the effect of antibiotics after culture and sensitivity of surgical sites infection cases and prevalence of surgical site infection among post surgical cases at Calicut Medical College . Methodology - The study was conducted in the Department of Microbiology, Medical College, Calicut for a period of one year from July 2007 to June 2008. One hundred and two cases of clinically suspected postoperative wound infection from the above cases was studied in detail. The study included 27 ‘clean’, 32 ‘clean-contaminated’ , 13 ‘contaminated’ and 30 ‘dirty’ cases. Two swabs were collected from each site. One swab was used for direct smear examination after Gram staining and second swab was subjected to culture and antibiotic sensitivity testing by standard microbiological techniques. Results - The incidence of postoperative wound infection was 5.36%. Among one hundred and two clinically suspected cases studied, bacteriologically proven surgical site infection was identified in thirty six patients. The prevalence of infection being 35% (36/102).Lowest infection rate was seen in clean(18.5%) surgery followed by clean-contaminated(37.5%), contaminated(38.5%) and dirty surgeries(47%). MRSA (Methicillin resistant Staphylococcus aureus) and multidrug resistant gram negative bacilli were predominant isolate. Change in antibiotic according to the culture and sensitivity report was made in ten cases.These ten cases had good response to treatment when put on appropriate antibiotics. Conclusion -. If the antibiotics given were sensitive to the isolate, infection was controlled without changing the antibiotic.But in ten cases a change to susceptible antibiotic after antibiotic sensitivity testing was made and infection was controlled completely in all these cases. culture and sensitivity from surgical site infection is mandatory in established infection.