A Survey of the Microbes in Human Bile

Abstract

Ninety-three bile samples, taken during surgery at three hospitals serving rural Kansas, were cultured for and anaerobic microorganisms. Forty-seven percent of the cultures were positive and 55% of these positive cultures grew anaerobes. Fifty percent (22 cultures) of the positive cultures contained one species and 15 of these grew anaerobes. Clostridium was the most frequent isolate and accounted for 22% of the total and anaerobic isolates. Isolates recovered less frequently were Escherichia coli (12%), Klebsiella (10%), and Propionibacterium (10%). The percent of cultures containing anaerobes and the incidence of Clostridium were high compared to other microbial studies for the biliary tract. However, the number of mixed cultures and cultures from which Bacteroides or E. coli were recovered was low. As anaerobes are more frequently recovered from clinical specimens, there is an increasing awareness and appreciation of their significance in human infections and disease processes. With biliary tract infections, the overall recovery of bacteria, both and anaerobic, depends on specific factors related to the disease and the type of culture technique employed. Numerous studies show an association between the incidence of positive biliary cultures and postoperative complications (Bergan et al., 1979; Bourgault et al., 1979; Cox et al., 1978; Jackaman et al., 1980; Keighley, 1977; Keighley et al., 1976; Lykkegaard Nielsen and This content downloaded from 157.55.39.132 on Thu, 15 Sep 2016 05:42:44 UTC All use subject to http://about.jstor.org/terms VOLUME 88, NUMBERS 1-2 21 Justesen, 1976; McLeish et al., 1977; Shimada et al., 1977). Some investigators (Bourgault et al., 1979; Jackaman et al., 1980) found that postoperative wound infections occurred significantly more often in patients whose bile contained anaerobic bacteria. Furthermore, studies in rabbits indicate that biliary infections result from a possible synergistic effect between and anaerobic (Justesen and Lykkegaard Nielsen, 1979; Lykkegaard Nielsen et al., 1976). Bacteriological studies on the human biliary tract employing anaerobic techniques have been done in other continents (Bergan, 1979; Jackaman et al., 1980; Keighley, 1977; Lykkegaard Nielsen and Justesen, 1976; Shimada et al., 1977) or large medical centers in North America (Cox et al., 1978; England and Rosenblatt, 1977; Lou et al., 1977). This investigation, undertaken at the suggestion of a pathologist in the area, is a survey of the microbial content of bile samples taken during surgery in three regional hospitals that serve rural Kansas. While the majority of individuals undergoing cholecystectomy have a normal recovery, those few with postoperative wound infections frequently become a substantial management problem. The purpose of this study was to identify microorganisms, particularly anaerobes, and to ascertain if a correlation exists between the microbial content of bile and postoperative complications. MATERIALS AND METHODS Sources of specimens. The hospitals have capacities of 32, 102, and 230 beds with a maximum distance of 264 km (165 miles) from Hays, Kansas. Ninety-three bile specimens were received between September 1977 and February 1980 and cultured routinely regardless of clinical symptoms. Thirteen miscellaneous wound specimens were obtained from the largest hospital and were cultured simultaneously with the bile under identical conditions. Collection and transport of specimens. All bile was collected at the time of surgery, inserted into a Vacutainer Brand Anaerobic Specimen Collector (Becton, Dickinson and Company), and transported by bus to Fort Hays State University and usually received the same day or the day following surgery. Culture procedures. All specimens were cultured for both anaerobic and bacteria. (The phrase aerobic bacteria is used to include all obligately and facultatively anaerobic bacteria.) The specimens were processed and all media were inoculated within a Coy flexible anaerobic glove box to minimize exposure to oxygen. The entire chamber, with an atmosphere of 5% H2, 10% CO2, and 85% N2, served as a 370C incubator. To isolate microorganisms, the specimens were plated on blood agar, phenylethyl alcohol agar, MacConkey agar, Tergitol 7 agar, and mannitol salts agar. The blood agar plate was incubated overnight at 370C under This content downloaded from 157.55.39.132 on Thu, 15 Sep 2016 05:42:44 UTC All use subject to http://about.jstor.org/terms 22 TRANSACTIONS OF THE KANSAS ACADEMY OF SCIENCE Table 1. Results of 93 bile culture analyses. No. of No. % isolates Rangec Specimens with positive cultures 44 47a 77 Cultures positive for: Anaerobes 24 55b 29 1-4 Anaerobes only 18 41 b 22 1-3 Aerobes only 20 45b 36 1-4 Mixed aerobes and anaerobes 6 14b 19 2-6