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Biomedical subjects

V L Sutter

Publications and source records attributed to V L Sutter.

At least 55 records · Page 3Linked to original sources
PubMed1977

Simple disk technique for detection of nitrate reduction by anaerobic bacteria.

The laboratory and clinical evaluation of a potassium nitrate-saturated disk for the rapid detection of nitrate reductase production in anaerobes was investigated. The optimal disk concentration and incubation time were determined by utilizing triplicate sets of quadrant plates prepared with supplemented brucella (Difco) blood agar and swabbed with a 24-h broth (BBL; 135 C thioglycolate) suspension of the test organism. Each set of plates received one control disk and three disks of varying concentrations of potassium nitrate (1 to 8 mg) with 0.1% sodium molybdate. All sets were incubated in GasPak jars for 24, 48, or 72 h, and subsequently sulfanilic acid and 1,6-Cleve's acid were added to each disk. A pink or red color change was indicative of nitrate reductase production. Eighty-eight stock isolates, 23 American Type Culture Collection strains, and 214 fresh clinical isolates were evaluated and compared with results obtained with tubes of preduced indole-nitrite medium (BBL) incubated for 7 to 10 days. The 6-mg disk incubated for 48 h yielded an overall agreement of 89% with the conventional tube technique, and fresh clinical isolates demonstrated better disk-tube agreement (93%) than previously frozen stock strains. The simplicity and ease of this disk test suggest its value as a preliminary screening procedure for nitrate reductase production. There were no false positives. Negative results by disk should be rechecked by tube.

Anaerobiosis↗
PubMed1976

A new approach to patients with suspected anaerobic postpartum pelvic infections. Transabdominal uterine aspiration for culture and metronidazole for treatment.

Oral metronidazole was given as therapy in 25 women with the clinical diagnosis of a postpartum anaerobic soft tissue pelvic infection following a vaginal delivery. There was a good clinical response in 80 per cent of these women. No anaerobic organisms resistant to metronidazole were recovered in the treatment failures. Different specimen collection techniques were evaluated, with anaerobes recovered in 4 per cent of the blood cultures, 26.3 per cent of the transabdominal endometrial aspirations, and 88 per cent of the transcervical endometrial samples. The aerobic recovery of organisms was 4 per cent from blood cultures, 15.8 per cent from transabdominal endometrial aspirations, and 96 per cent from the transcervical approach. The significance of these findings is discussed.

Abdomen↗
PubMed1976

Activity of combinations of antimicrobial agents against Bacteroides fragilis.

Thirty-two clinical isolates of Bacteroides fragilis were tested against nine pairs of antimicrobial agents by means of an agar dilution technique. A synergistic effect was observed with the combination of clindamycin and metronidazole. End points were achieved with 17 strains. Of these strains, 13 (76%) were inhibited by the combination of clindamycin and metronidazole; each drug was present at a concentration of less than or equal to 25% of its minimal inhibitory concentration when tested alone. This combination also showed synergistic bactericidal activity against three of six strains examined by a tube dilution technique. No antagonism was noted with any strain. The other eight combinations tested failed to show a consistent synergistic effect, although no antagonism was observed. These in vitro data indicate that antagonism is not likely to be encountered when combination therapy is used for B. fragilis infections. For selected B. fragilis infections, the combination of clindamycin and metronidazole may be useful.

Amikacin↗
PubMed1976

Susceptibility of respiratory tract anaerobes to orally administered penicillins and cephalosporins.

Anaerobic bacteria recovered from airway-related infections were tested by agar dilution against selected penicillins and cephalosporins available for oral administration. Against 136 isolates, penicillins G and V showed comparable activity, particularly when pharmacological differences were considered. Although many isolates were exquisitely susceptible to the penicillins, only 55% of the Bacteroides species and 72% of all isolates were inhibited at 0.5 mug of penicillin G per ml. Results for penicillin V at 1 mug/ml were similar (59 and 73%). The two cephalosporins were more active at achievable levels, inhibiting 94 to 95% of Bacteroides and 95 to 96% of all isolates at 8 mug/ml. These levels represent approximately 50% of the reported peak serum levels after oral administration of 625 mg of the penicillins and 500 mg of the cephalosporins. Dicloxacillin and nafcillin were tested against 50 isolates. The two were comparably active on a weight basis; dicloxacillin was more active when pharmacological differences were considered, but did not match the other penicillins or the cephalosporins.

Anaerobiosis↗
PubMed1976

Susceptibility of anaerobic bacteria to 23 antimicrobial agents.

The antimicrobial susceptibility of 492 anaerobic bacteria, the majority of which were recent clinical isolates, was determined by the agar dilution technique. Penicillin G was active against most of the strains tested at 32 U or less/ml, but only 72% of Bacteroides fragilis strains were susceptible at this level and 9% required 256 U or more/ml. Ampicillin was effective against most of the strains except B. fragilis at 16 mug or less/ml. Amoxicillin was active against only 31% of B. fragilis, 76% of other Bacteroides species, and 67% of Fusobacterium species at 8 mug/ml. Two new penicillins, mezlocillin and azlocillin, were similar to ampicillin in their activity. Carbenicillin and ticarcillin inhibited all but a few strains at 128 mug or less/ml. BLP 1654 was somewhat more active than penicillin G against B. fragilis but had similar activity against other anaerobes. Cephalothin was inactive against B. fragilis, and only 65% of other Bacteroides species were inhibited by 32 mug or less/ml. It was effective against all other anaerobes at that level. Cefamandole showed somewhat greater activity than cephalothin against B. fragilis but generally less activity against gram-positive organisms. Cefazaflur (SKF 59962) was comparable to cephalothin against B. fragilis. Cefoxitin was distinctly more active than cephalothin against B. fragilis. These latter two agents were less active than cephalothin against the gram-positive anaerobes. Chloramphenicol remains active against anaerobic bacteria at 16 mug or less/ml, with rare exceptions. Thiamphenicol was similar to chloramphenicol in its activity. Clindamycin was very active against most of the anaerobes at 8 mug or less/ml. Erythromycin and josamycin were also tested, with josamycin showing greater activity against B. fragilis than either erythromycin or clindamycin. A new oligosaccharide, everninomicin B, was less active than clindamycin against B. fragilis but more active against clostridia and some of the other strains tested. Most of the groups of bacteria tested demonstrated a trend toward resistance to tetracycline. Doxycycline and minocycline were somewhat more active than was tetracycline. Metronidazole was active against the majority of the anaerobes tested; resistance ws demonstrated by some of the gram-positive cocci and gram-positive, non-sporeforming bacilli.

Anaerobiosis↗
PubMed1976

Rosamicin: in vitro activity against anaerobes and comparison with erythromycin.

The in vitro activity of rosamicin was determined against 231 strains of anaerobic bacteria and compared with the activity of erythromycin against the same strains. Rosamicin and erythromycin had similar activity against strains of Peptostreptococcus and gram-positive nonsporeforming bacilli. Rosamicin was somewhat more active against strains of Peptococcus, Clostridium, and gram-negative anaerobes. All strains of Bacteroides fragilis tested were inhibited by 4 mug of rosamicin or less per ml, whereas only 76% of them were inhibited by this concentration of erythromycin. Rosamicin was distinctly more active against Fusobacterium nucleatum. Because of its in vitro activity, further investigation of the pharmacology of this drug is warranted.

Anaerobiosis↗
PubMed1976

Characterization of bacteroides melaninogenicus.

Fifty-eight human isolates of Bacteroides melaninogenicus, 42 from a variety of clinical infections and the rest from normal flora, were studied for pigment production and ultraviolet light fluorescence and by forty biochemical and other tests, including end-product analysis by gas-liquid chromatography. In a number of instances, tests were repeated several times and the results were reproducible. Agar plate dilution susceptibility tests were also performed to 12 antimicrobial agents. These 58 strains could be reliably placed into three groups, corresponding to the three subspecies described, based on seven characteristics. These included acid production in peptone-yeast-glucose medium, production of n-butyric acid from peptone-yeast-glucose medium, esculin hydrolysis, starch hydrolysis, indole production, effect on milk, and lipase production. Production of hydrogen gas in peptone-yeast-fructose medium may be another distinguishing characteristic. In general there was not much difference in the susceptibility of the three groups to the various antimicrobial agents tested. Two strains had a minimal inhibitory concentration of penicillin G of 16 and 32 U/ml, respectively. Three strains did not produce a black pigment in spite of prolonged incubation on blood-containing media.

Anaerobiosis↗
PubMed1976

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.

Anti-Bacterial Agents↗
PubMed1975

Susceptibility of Anaerobic bacteria to carbenicillin, cefoxitin, and related drugs.

The agar dilution technique was used for determination of the bacteriostatic activity of carbenicillin, penicillin G, cefazolin, cephaloridine, cefoxitin, and cephalothin agaomst a variety of anaerobic bacteria. Carbenicillin showed a high level of activity at a concentration of smaller than or equal to 100 mug/ml; only five of 123 strains of Bacteroides fragilis, one strain of Bifidobacterium eriksonii, and one strain of Clostridium bifermentans were resistant to a concentration of larger than or equal to 100 mug/ml. Cefoxitin, a beta-lactamase-resistant drug, was highly active against B. fragilis and most other anaerobes at a concentration of smaller than or equal to 32 mug/ml; the exceptions were one strain of Bacteroides species and 13 of 28 strains of Clostridium species. The other cephalosporins were less active against B. fragilis but exhibited good activity against most of the other strains tested. Bactericidal concentrations of cefoxitin and cephalothin were determined for 51 selected strains by the broth dilution technique, and the activities of these drugs were compared with those of two other drugs (clindamycin and metronidazole) known to be very active against anaerobes. Metronidazole wasthe most consistently bactericidal of the four drugs tested for this activity.

Anaerobiosis↗
PubMed1975

Disk susceptibility testing of slow-growing anaerobic bacteria.

The susceptibility of 55 strains of slow-growing anaerobes to eight clinically useful or potentially useful antibiotics was determined by agar dilution and disk diffusion tests. Strains of the genera Peptococcus, Peptostreptococcus, Megasphaera, Veillonella, Eubacterium, Bifidobacterium, Clostridium, and Fusobacterium were included. All strains were susceptible to chloramphenicol, but varied in their susceptibility to penicillin, lincomycin, clindamycin, tetracyclines, and vancomycin. Correlation between minimal inhibitory concentration and inhibition zone diameters was generally good. Prediction of susceptibility based on zone diameter measurements appeared satisfactory. Although routine susceptibility testing of anaerobic bacteria is not recommended, there are circumstances where such testing is relevant to the clinical situation. For those laboratories ill-equipped to do dilution tests, a disk diffusion test would give relatively accurate preliminary information. Quantitative susceptibility tests could then be done by a reference laboratory.

Anaerobiosis↗
PubMed1975

Treatment of anaerobic infections with metronidazole.

The results of treatment of 10 patients with anaerobic infections with metronidazole are presented. Six patients were cured, three showed initial good response but circumstances required a change to another drug, and one patient did not respond. The unique spectrum of the drug, its pharmacology, and limitations are discussed. The results indicate that further clinical trials to determine the efficacy of metronidazole in the treatment of anerobic infections are indicated.

Anaerobiosis↗
PubMed1975

Comparison of three procedures for biochemical testing of anaerobic bacteria.

The Analytab Products, Inc. (API), anaerobic multitest microsystem (MICRO) was compared with the Center for Disease Control conventional (CONV) thioglycolate (supplemented with hemin and vitamin K1) system and with pre-reduced anaerobically sterilized (PRAS) media as recommended by the Virginia Polytechnic Institute. Growth from a solid medium was suspended to produce standard inocula. Substrates included 16 carbohydrates, indole, urea, gelatin, and esculin. API strips were inoculated in air and incubated in GasPak (BBL) jars. MICRO tests were read at 1 and 2 days. CONV tests at 1, 2, and 7 days, and PRAS tests at 3 weeks. One hundred thirty well-characterized strains of anaerobes (76 gram-negative rods, 16 cocci, 26 gram-positive nonsporeforming rods, and 12 clostridia), including 48 reference strains, were studied. Of 2,600 tests performed, 2,085 (80.2%) showed agreement with all three methods. There was 90.9% agreement between the MICRO and CONV, 84.9% between the MICRO and PRAS, and 84.6% between the CONV and PRAS tests. All MICRO tests were reliable except for indole, which was not sensitive enough, and gelatin, which was very insensitive. The MICRO system permits performance of biochemical tests at the workbench in the average clinical laboratory without the need for expensive equipment and time-consuming procedures.

Anaerobiosis↗
PubMed1975

Practical aerobic membrane filtration blood culture technique: development of procedure.

The advantages of a membrane filter system for blood culturing have been realized for many years. Lysing of the blood prior to filtration is a convenient way to proceed, but previously described lysing procedures result in loss of certain organisms, particularly gram-negative bacilli. Four concentrations of Triton X-100 and sodium carbonate were studied in vitro, and their lysing and antibacterial properties were observed. A solution of 0.08% Na2CO3 and 0.005% Triton X-100 was found to have the least antibacterial effect and gave consistently good lysis and filtration times (under 3 min). An 8.3-ml amount of blood added to 190 ml of this concentration of lysing solution, filtered through three 47-mm membrane filters (0.45-mum pore size), led to recovery of 85% or more of various aerobic and facultative organisms in studies of artificially seeded blood.

Aerobiosis↗
PubMed1975

Practical aerobic membrane filtration blood culture technique: clinical blood culture trial.

During the course of preliminary clinical trials of an improved membrane filter blood culture system, filter plugging produced by a gelling of the lysing solution was observed when the patients had high leukocyte counts. A solution of streptokinase-streptodornase (Varidase, Lederle Laboratories) dissolved or prevented the gel and permitted rapid filtration without plugging. With streptokinase-streptodornase incorporated in the filtration procedure, a comparison of several culture systems was carried out on 176 blood cultures. Brucella broth with and without sodium polyanethol sulfonate, a prereduced osmotically stabilized broth, pour plates, and an improved aerobic membrane filter system were compared. The membrane filter system yielded 29 of the total of 37 positive cultures, far surpassing all other systems. Eight of these cultures were detected first by the filter technique, and 13 were positive only in this system. Nineteen of the 37 positive cultures were from patients on antimicrobial agents. Fourteen of these were detected by the filter, twice the number detected by any of the other systems.

Aerobiosis↗
PubMed1975

Oxygen tolerance of fresh clinical anaerobic bacteria.

The oxygen tolerance and sensitivity of 57 freshly isolated anaerobic bacteria from clinical specimens was studied. All the organisms tolerated 8 h or more of exposure to oxygen in room air. Growth of the isolates in increasing oxygen concentrations demonstrated that the 57 isolates varied in oxygen sensitivity from strict to aerotolerant anaerobes. Comparison of the oxygen tolerance and sensitivity showed that the most tolerant organisms (best survival after prolonged exposure) included anaerobes capable of growth at only 0.4% or less O2 (strict) as well as those able to grow in as much as 10% O2. The least tolerant were predominately strict anaerobes. Decrease in the inoculum size from a concentration of 10(8) to 10(6) colony-forming units per ml had only a minor effect. The data indicate that the brief oxygen exposure with bench techniques in clinical laboratories would not be deleterious to the anaerobic bacteria present in clinical specimens.

Anaerobiosis↗
PubMed1975

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.

Aerobiosis↗