Bacteriology of Surgical Site Infection and Study of Antimicrobial Susceptibility Pattern among the Patients Visiting Shree Birendra Hospital

Abstract

The present study was carried out in Shree Birendra Hospital, Chhauni, with a view to observe the pattern of bacterial isolates and their antibiotic susceptibility pattern from the infected surgical wounds of patients for the period of 7 months (October 2010 to May 2011).Altogether 200 wound specimens were collected and processed as per the standard protocol. Male patients were found to be more vulnerable to Surgical Site Infection constituting 61% (n=122) of the total patients than females 39% (n=78). The patients of working age groups 16-40 years were found to be highly affected with a significant difference in the incidence of SSI among males and females of different age groups. Most of the samples were collected from patients with orthopedic surgery (24.5%) followed by GI surgery (11%). Growth was found in 78% (n=156) pus specimens, out of which 83.3% (n=130) showed the growth of single bacteria and 16.7 % (n=26) showed the presence of multiple isolates. A total of 183 bacteria of 12 different species were isolated which included 4 species of Gram positive bacteria and 8 species of Gram negative bacteria. Out of 183 bacterial isolates 54.1% (n=99) were Gram positive bacteria and 45.9% (n=84) were Gram negative bacteria. Different types of organisms were isolated from different types of surgical sites. Staphylococcus aureus was the most common isolate (n=49, 26.78%) followed by CONS (n=43, 23.5%), Escherichia coli (n=39, 21.31%), Pseudomonas aeruginosa (n=17, 9.29%) and Klebsiella pneumonia (n=14, 7.65%). Other isolates were Klebsiella oxytoca, Morganella morganii, Enterobacter spp., Proteus mirabilis, Citrobacter fruendii, β-haemolytic streptococci and non-haemolytic streptococci. Antibiotic susceptibility pattern of the isolated organisms showed Polymixin B (78.14%) as the most effective drug followed by Amikacin (77.60%), Gentamicin (61.20%) and Pefloxacin (60.66%). Most of the bacteria were resistant to Cloxacillin (79.24%), Amoxicillin (49.73%), Cefepime (49.73%) and Ciprofloxacin (40.44%). Out of 49 isolates of S. aureus, 18.37 % (n=9) were MRSA and all of them were sensitive to Vancomycin. A significant number of isolates (75.96%) were found to be multi-drug resistant with 84.62% (n=33) of E. coli and 74.42% (n=32) of CONS, 78.57% (n=11) of K. pneumonia and 70.59% (n=12) of P. aeruginosa. Hence, SSI was found to be a predominant cause of morbidity for the surgical patients with male patients being affected more than the female patients. Therefore routine microbial analysis of surgical site infections and antimicrobial susceptibility pattern of the isolates is recommended so as to guide clinician for the treatment of surgical site infections.