Fecal bacteriology of colonic polyp patients and control patients.

Feces from 25 subjects with colonic polyps (multiple adenomatous, large single, or single with atypia) and from 25 matched control subjects were studied by detailed quantitative aerobic and anaerobic techniques, using a large battery of culture media and several atmospheric conditions. Over 55% of organisms detected on microscopic count were recovered anaerobically. In several cases, there were significantly different numbers of organisms of specific types recovered from the two different populations studied. However, these differed from organisms with "statistical significance" noted in a previous study from this laboratory involving two different diet groups (Japanese Americans on either a Japanese or a Western diet). Specific differences in bacteriology between groups with different risks of bowel cancer, noted in earlier British studies, were not noted in our present or previous study.

Transformation of 4-androsten-3,17-dione by growing cultures and cell extracts of Clostridium paraputrificum.

Growing cultures of Clostridium paraputrificum transformed 4-androsten-3,17-dione to 3 alpha-hydroxy-5 beta-androstan-17-one in a sequential manner with 5 beta-androstan-3,17-dione as an intermediate. The addition of 1.5 mM menadione to log-phase cultures which had formed 5 beta-androstan-3,17-dione resulted in a partial reoxidation of this steroid to 4-androsten-3,17-dione. However, this treatment also resulted in transient inhibition of culture growth. Resumption of growth was accompanied by complete reduction of 4-androsten-3,17-dione to 5 beta-androstan-3,17-dione. Cell extracts of C. paraputrificum were capable of carrying out these reductive transformations in the absence of added cofactors. However, Sephadex G-25 treated extracts required NADH or NADPH for these reactions. A flavin nucleotide, either FAD (plus NADH or NADPH) or FMN (plus NADH) was highly stimulatory for 4-androsten-3,17-dione reduction to 5 beta-androstan-3,17-dione. NADH was the preferred reduced pyridine nucleotide for reduction of the C4-C5 double bond, while time-course measurements suggested that NADPH was the preferred donor for reduction of the 3-keto group.

Bone infections involving anaerobic bacteria.

Over 700 cases of anaerobic osteomyelitis have been reported in the literature. Nonetheless, most reviews of osteomyelitis have paid little attention to the potential role of anaerobes in bone infections. There have, as yet, been no prospective studies of osteomyelitis utlizing optimal anaerobic transport and culture techniques. In a retrospective study of osteomyelitis at Wadsworth VA Hospital from 1973--1975, 39 percent of 58 patients with osteomyelitis had an infection involving anaerobes. Anaerobes were isolated from 81 percent of 27 patients whose specimens were cultured anaerobically. Anaerobes were isolated from nine of ten samples of bone. Anaerobic bacteria were part of a mixed flora involving facultative bacteria in all but two cases. All of the patients with anaerobic infection had non-hematogenous osteomyelitis. Non-hematogenous disease comprises 80--90 percent of the osteomyelitis seen in adults. Our experience at Wadsworth VA Hospital and a review of the literature lead us to believe that anaerobes play a much larger role in osteomyelitis than has been appreciated previously. Infections of the calvarium, mastoid, mandible, maxilla and the extremities are most likely to involve anaerobes. Predisposing conditions include paranasal sinusitis, otitis media, periodontal disease, trauma, peripheral vascular disease, peripheral neuropathy and/or chronic osteomyelitis. The presence of a foul odor is a valuable clinical clue to the presence of anaerobes. Bacteroides, fusobacteria and anaerobic cocci have been reported with almost equal frequency from anaerobic bone infections. While Bacteroides fragilis is the most common anaerobe isolated in infections of other organ systems, it does not appear to be a common pathogen in anaerobic bone infections. The role of anaerobes in osteomyelitis is not yet resolved. They have been isolated in pure culture from infected bone, and under those circumstances are clearly pathogenic. Anaerobes are found more frequently as part of a mixed flora with facultative streptococci, gram-negative bacilli, and less often with S. aureus. In this setting it is unclear which organism or organisms are the primary invaders, or whether there is a synergistic mechanism of infection. The reliability of sinus drainage cultures also remains to be determined. Our retrospective study suggests that certain anaerobes isolated from sinus drainage are not present in infected bone. Cultures of bone or an abscess adjacent to bone would be expected to give more reliable data. The majority of anaerobes other than B. fragilis are susceptible to levels of penicillin achievable with parenteral administration of the antibiotic. Anaerobic pathogens should be sought in the situations noted above. We feel that parenteral penicillin should be part of the initial antibiotic regimen in patients with suspected or documented anaerobic bone infection...

Fecal flora in different populations, with special reference to diet.

Although potent antimicrobial agents may effect rapid and significant changes in fecal microflora, changes in diet or dietary supplements usually produce modest changes by comparison. It may be, however, that even such minor changes may result in significant changes in metabolic activity, particularly in terms of production of possible carcinogens or cocarcinogens. It is clear that significant changes may occur in metabolic activity without major qualitative or quantitative changes in the fecal microflora. Other research that might help explain the epidemiological observations of the association between diet and colon cancer would be studies of the flora at different levels of the gastrointestinal tract (particularly the cecum and small bowel), studies of the mucosa-associated flora at different levels, and long-term dietary studies.

Diarrhea and colitis associated with antimicrobial therapy in man and animals.

Antimicrobial agent-induced ileocecitis of laboratory animals and colitis of man share common features. The significance of a newly described toxin in these two entities, the apparent source of the toxin (Clostridium difficile) and characteristics of the toxin are reviewed. Methods of toxin detection, isolation and rapid identification of C. difficile, and possible modes of therapy for antimicrobial agent-associated colitis of man are discussed.

Fecal microbial flora in Seventh Day Adventist populations and control subjects.

A comparison of 13 vegetarian Seventh Day Adventists with 14 nonvegetarian Adventists revealed relatively few statistically significant differences in fecal flora. A separate study involved a comparison of vegetarian Adventists (49 subjects), nonvegetarian Adventists (45), and non-Adventists on a conventional American diet (31) re: the incidence of the C. paraputrificum group in the fecal flora. The Adventist groups had significantly fewer C. septicum and C. tertium isolates than the non-Adventists. Reference to earlier diet studies done by our group revealed certain striking differences. Fusobacterium and C. perfringens counts were very low and lactobacillus counts very high in Adventists as compared with Japanese-Americans on either a Japanese or Western diet or Caucasian individuals on a conventional U.S. diet. Comparison of nonvegetarian Adventists with the other groups on a nonvegetarian Western diet also revealed several statistically significant differences. Finally, there were a number of significant differences in fecal flora when high risk groups (Japanese-Americans on Western diet and Caucasians on conventional U.S. diet) were compared with low risk groups (Japanese-Americans on a Japanese diet and Adventists).

Comparative activity of SCH 34343 against anaerobic bacteria.

The in vitro activity of SCH 34343 was compared with that of imipenem, clindamycin, cefoxitin, and metronidazole against 78 strains of anaerobic bacteria in the presence and absence of blood. Wilkins-Chalgren agar was used. SCH 34343 and imipenem were the most active agents, inhibiting all strains at less than or equal to 8 micrograms/ml. The addition of blood had little effect on the activity of any of the agents. Seven strains were unable to grow on Wilkins-Chalgren agar. Even with the addition of blood, one strain each of Bacteroides asaccharolyticus and Bacteroides bivius and two strains of Fusobacterium were unable to grow. Sixty-eight of the strains were tested against SCH 34343 and imipenem on Brucella lysed blood agar. Minimal inhibitory concentrations tended to be somewhat higher on Brucella lysed blood agar than on Wilkins-Chalgren agar, and all strains were able to grow on Brucella lysed blood agar.

Value of antibiotic prophylaxis in periodontal surgery.

THE MORBIDITY and incidence of bacteremia in periodontal surgery with or without cephalexin prophylaxis were assessed in adults on the basis of clinical evaluations and blood cultures. Cephalexin reduced the incidence of polymicrobic bacteremias. There was no correlation between objective signs of tissue healing and antibiotic coverage in treated or nontreated patients. In vitro antibiotic susceptibility data showed that cephalexin was active against the aerobic and anaerobic bacteria isolated from blood specimens taken during surgery.

Frequency of occurrence and antimicrobial susceptibility of bacterial isolates from the intestinal and female genital tracts.

In the selection of empiric therapy for infections of the female genital tract and intraabdominal infections in humans, the requisite information includes (1) the frequency of isolation of bacterial species dominant in the normal gastrointestinal and female genital tracts and in intraabdominal and female genital tract infections and (2) the in vitro susceptibilities of the dominant species to drugs that may be used against them (e.g., penicillin G, cefoperazone, cefoxitin, chloramphenicol, clindamycin, and metronidazole). The predominant bacteria in fecal contents are not necessarily those most frequently found in infections. Intraabdominal and perirectal infections are usually polymicrobial, resulting from mixtures of facultative species (coliforms and streptococci) and anaerobes. The predominant bacteria of the normal vagina and cervix are lactobacilli, facultative streptococci, Peptococcus species, and Peptostreptococcus species. Most infections of the female genital tract are due to mixtures of facultative enteric bacilli, streptococci, and anaerobes (Peptococcus and Peptostreptococcus species, Bacteroides fragilis, Bacteroides disiens, Bacteroides melaninogenicus, Bacteroides bivius, and Bacteroides asaccharolyticus). Of the antibiotics tested, clindamycin appears the most active against many of the groups of bacteria isolated.

Identification of Pseudomonas species isolated from hospital environment and human sources.

Methods and procedures are described for the identification of aerobic pseudomonads isolated from clinical specimens. Fluorescence is used as a means of primary differentiation. Final identification is based on the observation of characteristics such as flagellation, storage of intracellular fat, growth at 4 C and at 41 C, denitrification, gelatin hydrolysis, arginine dihydrolase activity, and oxidase activity. The value of this schema to the diagnostic laboratory is discussed.

In vitro susceptibility of anaerobes: comparison of clindamycin and other antimicrobial agents.

The in vitro activity of clindamycin against anaerobic bacteria was compared with that of other antimicrobial agents. Clindamycin remained effective against most anaerobic bacteria found in infections, although resistance to the drug was found in certain groups, such as Peptococcus and Clostridium species.

Anaerobes as normal oral flora.

The human mouth provides a suitable habitat for numerous bacterial genera. Anaerobic genera or genera that include anaerobic members found in the oral cavity are Actinomyces, Arachnia, Bacteroides, Bifidobacterium, Eubacterium, Fusobacterium, Lactobacillus, Leptotrichia, Peptococcus, Peptostreptococcus, Propionibacterium, Selenomonas, Treponema, and Veillonella. The incidence of anaerobes varies with age of the individual and with specific sites sampled. In edentulous infants, the incidence of anaerobes is relatively low. In adults, anaerobes are invariably present but are more prevalent in samples from the gingival sulcus than they are in samples from the gingival margin, tooth surfaces, buccal mucosa, tongue, or saliva. In samples from the healthy gingival sulcus, anaerobic, gram-positive bacilli are found in the range of 5%-14%; gram-negative bacilli in the range of 13%-29%; Veillonella in the range of 2%-8%; and gram-positive cocci in the range of 1%-15% of the cultivable flora. From marginal plaque and plaque from the tooth surface, gram-positive bacilli, gram-positive cocci, and Veillonella appear to be the predominant anaerobes. In saliva, Veillonella are the most numerous anaerobes.

Antimicrobial susceptibility testing of anaerobic bacteria.

Antimicrobial therapy of anaerobic infections is usually predicted on the basis of known patterns of susceptibility of anaerobic bacteria to antimicrobial agents rather than on results of in vitro tests of individual isolates. Routine susceptibility testing of anaerobic bacteria is not recommended, but there are instances of serious infection, i.e., endocarditis, or specific infecting organisms, e.g., Bacteroides fragilis, when in vitro testing of the specific infecting organism is indicated. No standard method has yet been accepted. Methods presently recommended are agar dilution or broth dilution tests. Other methods currently being evaluated are agar (disc) diffusion, broth-disc, and simplified broth and agar dilution tests. The advantages and limitations of the various methods are discussed.

Effect of carbon dioxide on erythromycin.

Exposure of erythromycin solutions to CO(2) or air for 18 h resulted in minimal deterioration under both conditions. Saturated disks exposed to the two atmospheres resulted in greater erythromycin deterioration, with slightly more deterioration occurring in the presence of CO(2). Reduction of activity was greatest when assays were conducted in a CO(2) environment.