The Incidence of Microbial Spectra in Gallstone Disease

Aim: The present study was undertaken to study the incidence of microbial spectra in gallstone disease and effect of bacteriobilia on wound infection.

Introduction: Biliary calculus disease is commonest disorder affecting the gastrointestinal tract and remains the most commonly encountered cause of morbidity. There is good evidence in the literature to support wound infection post cholecystectomy due to presence of bacteria in bile with reported incidence ranging from 4-10 % in various studies. Some surgeons use the outcome of bile cultures to guide their choice of empirical therapeutic antibiotics for subsequent wound infections. The present study evaluates the microbial spectra of bile in patients of chronic cholecystitis and association with postoperative wound infection in a rural setup.

Material and Methods: The study was conducted on fifty patients of symptomatic gallstone disease including all age group and both the gender, admitted in the department of General Surgery of MMIMSR, Mullana, Ambala during the period from August 2012 to August 2014. The study included 50 cases of chronic calculus cholecystitis randomly selected who were admitted to the surgical wards of our hospital in last 2 years. All the patients underwent cholecystectomy laparoscopic or open with or without common bile duct exploration. During surgery 2 to 3ml bile was taken for culture either from common bile duct or from the gall bladder for microbiological analysis in a sterile labelled container. Stones removed were classified according to visual appearance. Bile sample were inoculated on blood agar, macConkey’s agar and Robertson cooked meat media separately and incubated at 370C for 18 hrs. For aerobes colony morphology was read on blood agar, macConkeys agar after 18 hrs of inoculation and further subjected to staining and different biochemical reactions for species confirmation and then antibiotic sensitivity testing was done. For anaerobes from Robertson cooked meat media sample was further subcultured on BHI (Brain Heart Infusion) agar with metronidazole. BHI agar with metronidazole was kept in gas pack jar under anaerobic condition and incubated at 370C for 48 hrs. Colony morphology was read and confirmed with biochemical reaction. In the postoperative period all patients were given proper antibiotic coverage (first empirically and then according to culture report). Sutures were removed after 7-10 days in clean wounds. In cases of wound infection regular dressing of the wound was done, wound cultures sent and later on either secondary suturing was done or wound was left to heal by secondary intention.

Results: Bile exhibited positive culture in 14 (28%) case with Escherichia coli 7(14%) as the most common organism encountered followed by Klebsella 2(4%), Citrobacter 2(4%), Dipheroids 1(2%), Enterococcus Facaelis 1(2%), Candida 1(2%). Anaerobic organism growth was not seen in any of the bile culture.

Discussion: A bacterial cause of cholecystitis has been proposed and bacteria are cultured in up to 46% of patients with acute cholecystitis. Aspiration and culture of bile at the time of surgery for biliary tract diseases has provided a unique opportunity to study the bacterial flora, as this may have diagnostic, prognostic or with therapeutic implications. The mean age in present study for group A was 41.5 + 13.1 years and for group B was 47.8+ 12. Out of the 6 diabetic patients 5 developed wound infection (83.33%). The high rate of wound infection in diabetic was probably due to attenuated inflammatory response, impaired chemotaxis and inefficient bacterial killing. Open cholecystectomy was most common procedure done on 30 cases (60%) followed by lap. cholecystectomy 14 cases (28%). In 6 cases CBD exploration (12%) was done, out of which 4 (8%) patients showed bile culture positivity. Out of this group 3 cases (75%) had wound infection in postoperative period, probably due to the the bile spillage which occurred intraoperatively. Wound infection rate were lowest in lap. cholecystectomy group in which only 1 cases (7%) had post operative wound infection due to the small incision and minimal or no bile spillage. In open cholecystectomy group wound infection was found to be 4 cases (13.3%). The overall bacterial isolation rate in the present study was 28%.. Post operative wound infection in the biliary surgery is due to the endogenous contamination produced by opening of the biliary tract with bacteriobilia. Both post operative wound infection and septicaemia are caused by the same organism. This observation was also seen in the present study where accidental contamination of wound with bile having bacteria showed post operative wound infection. In our study bile spillage was seen in 36% cases with associated wound infection in 18% cases. In Group A cases bile spillage was seen in approx 35.7% cases with wound infection in 42.8% cases suggesting the association of bacterial isolates in bile with wound infection. Study also showed association of pigment stones with bile culture positivity.

Conclusion: Infected bile strongly predisposes to postoperative wound infection with the same organism. Bile spillage during intraoperative period of bile containing bacteria predisposes to post operative wound infection. Prophylactic antibiotic should be administered to all the cases undergoing cholecystectomy.