A 7-Year Survey of Drug Resistance in Aerobic and Anaerobic Fecal Bacteria of Surgical Inpatients: Clinical Relevance and Relation to Local Antibiotic Consumption

Abstract

One-day studies of bacteriological cultures of fecal specimens obtained from 409 surgical inpatients at 5 occasions enabled rapid assessment of antibiotic resistance in aerobic and anaerobic bacteria, relevant to abdominal infection. This novel approach to surveillance of drug resistance was tested in a 7-year survey at a surgical department. A distinct correlation between local drug consumption and prevalence of resistant fecal bacteria was recorded for ampicillin and doxycycline. 17 other agents studied showed no such obvious correlations. Huge increases of cefuroxime and metronidazole consumption caused no emergence of drug resistant aerobic and anaerobic fecal bacteria. Imipenem was the only agent tested, which inhibited both the aerobic and anaerobic fecal bacteria of nearly all patients.

Antimicrobial resistance in human oral and intestinal anaerobic microfloras

“…B. thetaiotaomicron and B. ovatus were the most commonly isolated members of the B. fragilis group. In previous studies, B. ovatus and then B. fragilis were the most frequently isolated anaerobic resistant strains from intestinal microfloras (1,12). The antimicrobial susceptibility of the B. fragilis group in the present study correlates well with those found in recent investigations in Canada and Europe (12,16).…”

“…In the outpatient group, one-third of the resistant strains made up more than 1% of the total anaerobic microflora, while in both hospitalized groups, two-thirds of the resistant strains constituted more than 1% of the total anaerobic fecal flora. Strains from the B. fragilis group were isolated most frequently, as has been reported previously (1,3,12). B. thetaiotaomicron and B. ovatus were the most commonly isolated members of the B. fragilis group.…”

“…The most important factor in beta-lactam resistance appears to be the production of P-lactamases, which have been found in various Bacte-roides, Fusobacterium, and Clostndium species (15 The increased use of cefuroxime and metronidazole has not been correlated with the emergence of drug-resistant aerobic or anaerobic intestinal bacteria (12,13). Since the most common drug regimen in the present study was cefuroxime, which was often used in combination with metronidazole, it is not surprising that no major differences between the hospitalized patient groups were found.…”

“…Bacteria from the intestinal microflora dominate as causative agents in postoperative infections, and resistance among them may seriously complicate the prophylaxis and treatment of intra-abdominal infections (12).…”

“…Those investigations have mainly focused on aerobic bacteria; it has been shown that administration of ampicillin or tetracycline significantly increases the number of resistant gram-negative aerobic microorganisms in the fecal flora, while other agents such as amoxicillin, cefuroxime, imipenem, and metronidazole have been shown to have no impact on the development of resistance patterns (12,18).…”