Study on Bacteriological profile of Wound Infections in Tertiary Care Hospital.

INTRODUCTION : Skin, the largest organ in the human body, plays a crucial role in the sustenance of life through the regulation of water and electrolyte balance, thermoregulation, and by acting as a barrier to external noxious agents including microorganisms, however , when the epithelial integrity of skin is disrupted, a wound results. A wound is breach in the skin and the exposure of subcutaneous tissue following loss of skin integrity provides a moist, warm and nutritive environment that is conducive to microbial colonization and proliferation. In developing countries like India, large number of people die daily of preventable and curable diseases such as wound infections. Wound infections are one of the most common hospital acquired infections and are an important cause of morbidity and account for 70-80% mortality. The importance of wound infections, in both economic and human terms, should not be underestimated. In a study on an average, patients with an infected wound stay about 6-10 days more than if the wounds heal without infections. The wound infection depends on a complex interaction between host factors like immunity, nutritional status and age , wound related factors like magnitude of trauma, dead space, devitalization and presence of hematoma and microbial factors like toxins, invasion and resistance to antibiotics. Most wound infections can be classified into two major categories, skin and soft tissue infections, although they often overlap as a consequence of disease progression. AIMS AND OBJECTIVES : 1. To isolate and identify the organism causing wound infections. 2. To detect the antimicrobial susceptibility pattern of the bacterial isolates. 3. To find out the incidence of Methicillin Resistant Staphylococcus aureus. 4. To find out the incidence of Extended Spectrum Beta Lactamase producers among Enterobacteriaceae isolates. 5. To select appropriate antibiotic for effective treatment. MATERIALS AND METHODS : A total of 289 patients with wound infection attending as outpatient and inpatient in Kilpauk Medical College and Hospital ,Chennai were included in the study. Study period: March 2009 to February 2010. Clinical samples like pus, tissue material and discharge from the incised lesions or ulcers were analyzed for bacteriological profile and antimicrobial susceptibility pattern. Staphylococcus aureus strains were analyzed for MRSA and Enterobacteriaceae isolates obtained were analyzed for ESBL production. The methodology included, 1. Collection of specimen, 2. Specimen processing, 3. Identification of pathogens, 4. Antimicrobial susceptibility testing, 5. Double disk synergy test for ESBL, 6. Minimum inhibitory concentration, 7. Phenotypic confirmatory test for MRSA. RESULTS : Specimens obtained from patients with wound infection attending Surgical, Orthopaedic, Burns ward, OG, IMCU, Plastic surgery departments as OP and IP were studied from March 2009 to Feb 2010 to identify the bacteriological profile of wound infection, antimicrobial susceptibility pattern of the organisms isolated ,incidence of MRSA and ESBL producing Enterobacteriaceae among them. Study included patients of both sexes and up to 80 years of age .Specimen included were pus, wound swab. Wound swabs from 289 patients were analyzed in the study. Male patients constituted 143(49.48%), Female patients constituted 146(50.51%), age ranged from 3 months to 80 years. Bacterial isolates were found in 164 (56.74%). The isolation rate was significantly higher in females (51.21%), compared to males (48.78%). The predominant isolates were Gram positive bacteria 96(58.53%). The most frequently isolated organisms were Staphylococcus aureus 89(54.26), followed by Klebsiella pneumoniae (24.39%), Pseudomonas aeruginosa 22(13.41%), Escherichia coli 5(3.04%), Enterococci 5(3.04%), Coagulase negative Staphylococcus 2(1.21%), Acinetobacter 1(0.60%). CONCLUSION : The predominant isolate was found to be Gram positive bacteria 96 (58.53%) than Gram negative bacteria 68 (41.46%).However Staphylococcus aureus 89 (54.26%) was seen as the most common bacterial pathogen followed by Klebsiella pneumoniae 40 (24.39%) and Pseudomonas aeruginosa 22 (13.41%) • Among the Staphylococcus aureus 36 (40.44%) were found to be MRSA and were susceptible to vancomycin (100%), levofloxacin (97.2%), amikacin (94.4%). • Detection of MRSA were found to be high with cefoxitin disk than oxacillin screen agar . • Among Enterobacteriaceae isolates 19 (42.2%) were found to be ESBL producers and were susceptible to amikacin (89.5%). • By employing standard microbiological techniques meticulously the causative agents can be isolated and antimicrobial sensitivity can be assessed for proper management of wound infection. • Essential infection control practices including hand washing by hospital personnel and provides better control of antibiotic resistant strains