Biomedical subjects
Publications and source records attributed to V M Bieluch.
A case report is presented of a patient with acute postoperative pancreatitis who developed a pancreatic abscess secondary to Candida albicans. Recovery followed operative drainage and amphotericin B therapy. Because this is the only such patient in the author's career experience, and because only one other report currently addresses the problem, this report is offered.
Histologic and bacteriologic evaluations of tonsils removed at surgery from ten patients with a diagnosis of recurrent tonsillitis were performed. The bacteriology was complex, with an average of 6.3 aerobic bacteria and 3.3 anaerobic bacteria isolated from each patient. Histologic sections revealed chronic cryptitis, with intact tonsillar architecture. These findings provide a possible explanation for the failure of commonly used antibiotic regimens to eradicate recurrent infection from this site.
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Resistance to cefoxitin among species of the Bacteroides fragilis group of organisms has remained low (8%-10%) in a multicenter nationwide survey. However, a statistically significant increase in the percentage of B. fragilis group organisms resistant to cefoxitin was found at Tufts-New England Medical Center from 1981 to 1982. Non fragilis species accounted for most of the resistance. The presence of cefoxitin resistance in B. fragilis isolates correlated with resistance to other antibiotics. The presence of cefoxitin-resistant B. fragilis group organisms also correlated with the presence of other cefoxitin-resistant bacteria. No difference could be detected in therapeutic outcome of patients with cefoxitin-sensitive or cefoxitin-resistant B. fragilis group organisms, regardless of treatment with cefoxitin or other antibiotics.
Knowledge of the mechanisms of antimicrobial resistance and resistance transfer in anaerobic bacteria has been gained over the past several years. There is widespread resistance to the beta-lactam antibiotics in the B. fragilis group of organisms and there is emerging penicillin resistance in other Bacteroides species. These resistances are usually mediated by chromosomal beta-lactamases. There have been two new beta-lactamases described in Bacteroides; a penicillinase which inactivates ureidopenicillins and another that inactivates cefoxitin. The transfer of the common beta-lactamase, penicillinase, and cefoxitin resistance has been documented in B. fragilis. The mechanism of tetracycline resistance in B. fragilis is the lack of accumulation of intracellular drug; the resistance is widespread in anaerobic bacteria and is seen in two-thirds of the B. fragilis strains. The transfer of tetracycline resistance is common, however, no transfer factor has yet been isolated. Clindamycin-erythromycin resistance in Bacteroides was first recognized in the mid-1970s and transferable resistance was described in 1979. The mechanism of resistance is probably similar to macrolide-lincosamide-streptinogramin-resistance seen in aerobic bacteria. Two clindamycin resistance transfer factors, pBFTM10 and pIP410 (pBF4) have been described. A common resistance determinant found both on plasmids and chromosomes is widely distributed in nature and it probably resides on a transposon. DNA homology studies indicate that there is more than one type of clindamycin resistance in Bacteroides; a newly recognized clindamycin resistance determinant is transferable. Local outbreaks of clindamycin resistance have been noted in the United States and in Europe. The susceptibility of Bacteroides in the United States in 1983 from a multi-center study reveals a 5% incidence of resistance in B. fragilis and 1% in Bacteroides species. The rate of clindamycin resistance has remained steady over the past three years in the Bacteroides fragilis group.
Clinical and experimental data provide evidence for interactions between aerobic and anaerobic organisms in abscess formation. The organisms present represent a subset of those normally found at nearby mucosal surfaces. Certain organisms, most notably B. fragilis, emerge from the normal flora as important in abscess formation. Suspected virulence factors for B. fragilis include oxygen tolerance, capsular polysaccharide and the other enzymes produced by this organism. Other factors, as yet incompletely understood, probably play a role. In addition, the large number of organisms present in an abscess, the presence of antibiotic inactivating enzymes, the hostility of the anaerobic environment to antimicrobial activity and host defences, as well as the fibrous capsule surrounding an abscess, contribute to the persistence of infection despite antibiotic therapy and the need for drainage. The contribution of both aerobic and anaerobic organisms in the formation of abscesses must be remembered when one chooses antibiotic therapy for such infections.
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Mycobacterium haemophilum, previously characterized as an unusual pathogen, is found primarily in immunocompromised hosts. This organism has stringent growth characteristics and may not be isolated using routine techniques. M. haemophilum infects the skin and underlying tissues, a circumstance which reflects the organism's propensity for growth in a cooler environment. Infections have been reported in renal transplant recipients, patients with Hodgkin's disease, and, more recently, patients with AIDS. The organism has also been isolated from children with cervical lymphadenitis in the absence of apparent immunodeficiency. Response to therapy has not been uniform, and in some instances improvement in immune status has been associated with regression of lesions. With proliferation of transplantation surgery, chemotherapy, and AIDS, the number of infections due to M. haemophilum is likely to increase.