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Biomedical subjects

C L Wells

Publications and source records attributed to C L Wells.

At least 91 records · Page 5Linked to original sources
PubMed1987

The role of Bacteroides encapsulation in the lethal synergy between Escherichia coli and Bacteroides species studied in a rat fibrin clot peritonitis model.

Encapsulation in Bacteroides species has been thoroughly studied in vivo as a virulence factor in abscess formation. Its pathogenic role in lethal infections caused by a mixture of pathogens has been less well investigated. Our previous studies using the rat fibrin clot peritonitis model have demonstrated lethal synergy between Bacteroides fragilis and Escherichia coli. In order to determine the synergistic role of the encapsulation of the Bacteroides component in this model, inoculations of E. coli plus one of seven Bacteroides strains of differing degrees of encapsulation were assessed for their effect on mortality. Both unencapsulated Bacteroides strains tested (B. distasonis 1244, B. vulgatus 4300) produced an early lethal synergistic effect with E. coli while the heavily encapsulated strain, B. thetaiotaomicron 1603 did not do so. The four other Bacteroides strains tested were encapsulated and their synergy with E. coli was demonstrated. Control Gram-positive strains, Streptococcus faecalis and Staphylococcus aureus, did not alter mortality when mixed with E. coli in this model. These studies support the concept that virulence factors other than encapsulation are important in the outcome of polymicrobial infections in which Bacteroides species play a part.

Animals↗
PubMed1987

The importance of surveillance stool cultures during periods of severe neutropenia.

The correlation of fecal gram-negative bacilli (GNB), neutropenia, and bacteremia was studied in 45 bone marrow transplant recipients. Weekly stool cultures were prospectively monitored for GNB resistant to routine prophylactic and empiric antimicrobial agents. Seven cases of GNB bacteremia occurred in 45 patients described as follows. Twenty-three patients had no fecal or blood GNB. Fifteen patients had fecal GNB and no blood GNB; three of these latter patients had less than or equal to 50/mm3 circulating white blood cells (WBC) at the time of isolation of fecal GNB but two of the three were concurrently receiving appropriate empiric antibiotics. Two patients had blood GNB but no fecal GNB: one patient had a trimethoprim/sulfamethoxazole (TMP-SMZ)-sensitive isolate that would not be detectable in the feces by our methodology and one patient had feces analyzed only after the bacteremic event. Five patients had fecal GNB and blood GNB: one of these patients did not have a fecal sample analyzed prior to bacteremia but the remaining four patients had the same species/antibiogram of GNB isolated from the feces two to three days prior to the detection of bacteremia. Thus, the fecal GNB could have been used to predict the antibiogram of the subsequent blood GNB. In addition, all four of these latter bacteremic patients had less than or equal to 50/mm3 circulating WBC at the time of documented fecal GNB. Thus, bone marrow transplant recipients with fecal GNB coupled with severe neutropenia (less than or equal to 50/mm3 circulating WBC) were more likely to develop bacteremia (P less than 0.02) than were those with fecal GNB and greater than 50/mm3 circulating WBC.

Adult↗
PubMed1987

Hydrostatic weights of patients with spinal injury. Reliability of measurements in standard sit-in and Hubbard tanks.

The purpose of this study was to estimate the reliability of body density measurements from the hydrostatic weights of subjects with spinal injuries in standard sit-in and Hubbard tanks. Nineteen outpatients with spinal injuries participated in the study. Residual lung volume and hydrostatic weights were measured in two laboratories. Body density and percentage of body fat were determined from hydrostatic weights. Statistical tools were the t test for correlated samples and the Pearson product-moment correlation coefficient. The alpha level was set at .05. Reliability coefficients for body density and percentage of body fat were .98 and .99, respectively (p less than .05). Trial means were not significantly different. We conclude that a standard sit-in tank or a Hubbard tank can be used to determine body density and percentage of body fat of patients with spinal injuries. Modifications should be made for sitting posture, and standard densitometric procedures should be followed.

Adult↗
PubMed1987

Role of anaerobic flora in the translocation of aerobic and facultatively anaerobic intestinal bacteria.

It is thought that the normal enteric microflora acts not only to prevent intestinal colonization but also to prevent subsequent systemic dissemination of ingested, potentially pathogenic bacteria. To determine the relative roles of specific components of the intestinal bacterial flora in bacterial translocation out of the gut, mice were given various antimicrobial agents to selectively eliminate specific groups of intestinal bacteria. The cecal flora and the translocating bacteria in mesenteric lymph nodes were monitored both before and after oral inoculation with antibiotic-resistant Escherichia coli C25. Orally administered streptomycin selectively eliminated cecal facultative gram-negative bacilli, orally administered bacitracin-streptomycin eliminated all cecal bacterial species except low numbers of aerobic sporeformers, and parenterally administered metronidazole selectively eliminated cecal anaerobic bacteria. Compared with control mice, only metronidazole-treated mice had significantly increased rates of dissemination of intestinal bacteria into mesenteric lymph nodes, indicating that the exclusive absence of anaerobic bacteria facilitated the translocation of the intestinal facultative bacteria. In a parallel experiment with streptomycin-resistant E. coli C25 as a marker, parallel results were obtained. Metronidazole increased the translocation of the marker strain and the indigenous strains of intestinal bacteria. Thus, anaerobes appeared to play a key role in confining indigenous bacteria to the gut. However, intestinal colonization and translocation of E. coli C25 occurred most readily after bacitracin-streptomycin treatment, suggesting that in addition to anaerobic bacteria, other bacterial groups may play a role in limiting the intestinal colonization and extraintestinal dissemination of E. coli C25.

Administration, Oral↗
PubMed1987

Ability of intestinal Escherichia coli to survive within mesenteric lymph nodes.

Identification of mesenteric lymph node (MLN) bacteria showed that indigenous streptomycin-sensitive Escherichia coli could be recovered from MLN at least 48 h after this organism had been essentially eliminated from the cecal flora by antibiotics and replaced with exogenous streptomycin-sensitive E. coli JK. Additional experiments with antibiotic-treated rats also showed that indigenous streptomycin-sensitive E. coli could be recovered from the MLN 4 days after elimination of this organism from the cecal flora. These findings suggest that the time of bacterial translocation to MLN may be kinetically different from the time of recovery of bacteria from MLN and that the MLN may be a focus of infection with intestinal bacteria.

Animals↗
PubMed1987

Fluid shifts with successive running and bicycling performance.

Seven men and five women triathletes ran 10 km and bicycled 40 km at race pace for the purpose of studying changes in plasma, blood, and red blood cell volumes. A second trial followed 1 wk later with the order of exercise counterbalanced (running first-cycling second; cycling first-running second). Water consumption was measured by providing water bottles on the bike phase, at 3.2 and 6.7 km on the run phase, and at the transition area. Body weight was obtained at the start and end of each phase. A 10-ml blood sample was obtained just before starting and immediately upon finishing each phase. Changes in plasma volume, blood volume, and red cell volume were calculated from hematocrit and hemoglobin values. Changes in blood volume, plasma volume, and red cell volume did not differ between the sexes; therefore, results were combined. Sequential cycling and running caused significant hemoconcentration (-6 to -8% blood volume; -8 to -10% plasma volume) with moderate dehydration (-3 to -4% body weight) despite ad libitum fluid replacement. More severe fluid compartment shifts occurred on the initial phase regardless of exercise mode. Blood volume and plasma volume changes during the second mode of exercise were minor in extent with the major differences occurring in red cell volume. When fluid changes were calculated on a per hour basis, shifts were greater during running than during cycling.

Bicycling↗
PubMed1986

Intestinal bacteria translocate into experimental intra-abdominal abscesses.

Experimental intra-abdominal abscesses were initiated by surgical implantation of a fibrin clot contaminated with either Bacteroides fragilis, Bacteroides thetaiotaomicron, or B fragilis-Escherichia coli. Seven days after surgery the numbers of bacteroides (per gram) in B fragilis and B thetaiotaomicron abscesses were typically log10 8.4 +/- 0.5 (n = 6) and log10 6.4 +/- 0.6 (n = 4), respectively; B fragilis-E coli abscesses typically contained log10 8.9 +/- 0.5 B fragilis and log10 7.6 +/- 0.6 E coli (n = 5). Of 38 B fragilis abscesses, 14 B fragilis-E coli abscesses, and nine B thetaiotaomicron abscesses, additional intestinal bacteria were recovered from 21 (55%), 13 (93%), and seven (89%) abscesses, respectively. The additional organisms, in decreasing order of frequency, were enterococci, E coli, staphylococci, alpha-streptococci, lactobacilli, and Proteus species in numbers ranging from 2.5 log10 to 7.9 log10 per gram of abscess. Histologic sections of contaminated abscesses adherent to the intestine, liver, or spleen revealed normal tissue histology and no breakdown of the abscess wall. Thus, intestinal bacteria translocated into intra-abdominal abscesses by a mechanism that did not appear to be surgical soilage.

Abdomen↗
PubMed1985

Comparative in-vitro activity of Sch 34343 for a wide spectrum of clinically significant anaerobic bacteria.

One hundred and fifty strains of anaerobic bacteria including 45 bacteroides, 19 fusobacteria, 41 cocci, 34 clostridia, and 11 Gram-positive non-sporeforming rods were tested by agar dilution for their susceptibilities to cefoxitin, cefuroxime, latamoxef (moxalactam), penicillin G, chloramphenicol, clindamycin, metronidazole and Sch 34343. Excluding the 34 clostridia, 115 of the 116 remaining strains were inhibited by less than or equal to 1 mg/l of Sch 34343. One isolate of Bacteroides fragilis required 32 mg/l for inhibition. All of the 34 clostridia were inhibited by less than or equal to 8 mg/l of Sch 34343: 14 isolates of Clostridium difficile had an MIC50 and an MIC90 of 4 mg/l, whereas the remaining 20 species of clostridia had an MIC50 of 0.125 mg/l and an MIC90 of 2 mg/l. On a weight basis, Sch 34343 was generally more active than any of the seven other antimicrobial agents tested.

Anti-Bacterial Agents↗
PubMed1985

In-vivo bactericidal activity of Sch 34343 in Bacteroides fragilis abscesses and in Bacteroides fragilis-Escherichia coli abscesses.

Bacteroides fragilis pure-culture abscesses and Bact. fragilis-Escherichia coli mixed-culture abscesses were initiated subcutaneously in mice and intraperitoneally in rats. Within 1 h after injection of Sch 34343, the drug was present in higher concentrations in the abscesses than in the blood of infected animals. After five days of Sch 34343 therapy with either 100 or 400 mg/kg administered five times a day to mice with subcutaneous abscesses, the numbers of Bact. fragilis in pus decreased approximately three log-fold, reflecting a killing of 99.99% of the viable Bact. fragilis, while the numbers of E. coli decreased approximately 0.5 log-fold, reflecting a killing of 50% of the viable E. coli. After five days of therapy with either 50 or 150 mg/kg administered five times a day to rats with intraperitoneal fibrin clot abscesses, the viable Bact. fragilis again decreased three log-fold; the viable E. coli decreased one log-fold in rats given the higher dosages of the drug. Sch 34343 is a promising agent for the treatment of anaerobic infections because it can penetrate into anaerobic abscesses and can kill large numbers of bacteria within abscesses.

Abscess↗
PubMed1985

Comparison of PRAS II, RapID ANA, and API 20A systems for identification of anaerobic bacteria.

This study evaluated the PRAS II, RapID ANA, and API 20A systems for the identification of anaerobic bacteria. A total of 80 isolates (68 fresh clinical isolates and 12 stock cultures) were examined and included 25 Bacteriodes spp., 7 Fusobacterium spp., 12 Clostridium spp., 2 Veillonella spp., 16 gram-positive cocci, and 18 gram-positive nonsporeforming bacilli. All isolates were initially identified by the procedures outlined in Holdeman et al. (ed.), Anaerobe Laboratory Manual, Virginia Polytechnic Institute and State University, Blacksburg, Va., 1977; identifications from the PRAS II, RapID ANA, and API 20A systems were compared with these initial identifications. If no supplemental tests were required, the RapID ANA and API 20A systems had incubation times of 4 and 24 h, respectively; the PRAS II system generally required 2 to 5 days of incubation, depending on the growth rate of the isolate. PRAS II identified 74% correct to species level, 14% correct to genus only, and 6% incorrect; 6% could not be identified. PRAS II data were reevaluated according to a revised data base that was provided after completion of the study; PRAS II (revised) identified 82% correct to species, 12% correct to genus only, and 6% incorrect. RapID ANA identified 62% correct to the species level, 28% correct to genus only, and 10% incorrect. API 20A identified 71% correct to the species level, 10% correct to genus only, and 3% incorrect; 16% could not identified. The API 20A is a more established system for identification of anaerobic bacteria; PRAS II and RapID ANA appear to be promising new methods for the identification of anaerobic bacteria.

Bacteria, Anaerobic↗
PubMed1985

Mechanism of the adjuvant effect of hemoglobin in experimental peritonitis. IX: The infection-potentiating effect of hemoglobin in Escherichia coli peritonitis is strain specific.

Hemoglobin solutions have been said to consistently increase the lethality of otherwise nonlethal bacterial inocula in experimental models of Escherichia coli peritonitis. We tested the capacity of stroma-free hemoglobin to potentiate the lethality of each of 26 separate clinical isolates of E. coli. The LD50 of each strain with and without stroma-free hemoglobin was then correlated with the ability of that strain to express putative "virulence characteristics": the expression of 0 (lipopolysaccharide) and K (capsular) antigens, the ability to produce colicin V, the capacity to hemagglutinate mammalian red cells in the presence of 1% mannose, and the ability to secrete alpha-hemolysin. No perfect correlations were found. The LD50 of only four of the 26 strains of E. coli was affected by hemoglobin. Each of these four strains could hemagglutinate red cells and secreted alpha-hemolysin. Many other strains whose lethality was not increased by hemoglobin also had these virulence properties. We must conclude that the infection-potentiating effect of hemoglobin cannot be shown for most clinical isolates of E. coli and that the mechanism cannot be correlated with the usual "virulence characteristics" of E. coli.

Adhesiveness↗
PubMed1985

Physiological responses to a 20-mile run under three fluid replacement treatments.

Ten experienced male marathon runners ran 20 miles (32.18 km) on an outdoor course in a warm climate to measure responses in selected physiological variables as a result of drinking water, an electrolyte-glucose solution (ERG), or a caffeine solution (5 mg X kg-1 body weight) before and during the run. The caffeine solution and water were colored and flavored to resemble the electrolyte-glucose solution so that a double-blind condition could be maintained. Subjects ingested a different fluid in each of the three trials in a counterbalanced design. Parameters studied were: heart rate; rectal temperature; body weight; hemoglobin and hematocrit; serum glucose, sodium, potassium, chloride, and free fatty acids; perceived exertion; respiratory exchange ratio (R); and fractional utilization of VO2max (percentage of VO2max). Both R and percentage of VO2max were higher in subjects who drank the caffeine solution compared to those who drank water. Although post-run free fatty acid mean values were significantly higher than pre-run levels, there were no statistically significant differences among the fluid treatments. Since no other differences were observed, we concluded that, under the outdoor road-running conditions encountered here, these fluid replacement treatments did not differ in their effects on the parameters studied.

Adult↗
PubMed1984

Incidence of trimethoprim-sulfamethoxazole-resistant enterobacteriaceae among transplant recipients.

Of 114 recipients of pancreatic, renal, and bone marrow transplants who were given trimethoprim-sulfamethoxazole (TMP-SMZ) for antimicrobial prophylaxis, 44 (39%) had a total of 52 fecal isolates of TMP-SMZ-resistant gram-negative bacilli. In most of these 44 patients, the resistant isolate was found at a concentration of greater than or equal to 10(6) organisms/ml of feces. Escherichia coli was the most frequent of the isolates, and Citrobacter freundii was the next most frequent. Eight of the 114 transplant recipients had gram-negative bacteremia; in six of these eight patients, a TMP-SMZ-resistant gram-negative bacillus was the etiologic agent of bacteremia. Four of the latter six patients had stool cultures analyzed prior to the detection of bacteremia; all four had high concentrations (greater than or equal to 10(8)/ml) of fecal TMP-SMZ-resistant E. coli one to 20 days before they were found to have E. coli bacteremia. In each of these instances, the E. coli isolates from the stool and the blood had similar antibiograms. These findings indicated that resistance to TMP-SMZ is becoming more prevalent and that the screening of patients for the presence of fecal TMP-SMZ-resistant Enterobacteriaceae prior to initiation of long-term therapy with this antimicrobial agent may be worthwhile.

Bone Marrow Transplantation↗
PubMed1983

Clostridium tetani growth and toxin production in the intestines of germfree rats.

Germfree rats were challenged orally and intrarectally with spores of Clostridium tetani. Although C. tetani spores remained viable in the intestinal tract, they were unable to germinate. Germfree rats were then challenged orally with vegetative cells of C. tetani. Vegetative cells were able to colonize the intestinal tract, replicate, and produce toxin. Tetanus antitoxin, but no tetanus toxin, was detected in the sera of monoassociated rats.

Animals↗
PubMed1983

Evaluation of serum arabinitol as a diagnostic test for candidiasis.

Gas-liquid chromatography was used to quantitate the arabinitol concentration in the sera of patients with candidiasis and in that of control patients. Serum arabinitol was elevated in 59% (n = 34) of patients with Candida sepsis, in 39% (n = 38) with Candida colonization, in 14% (n = 62) with bacterial sepsis, and in 0% (n = 11) of normal persons. The above patients were subsequently divided on the basis of renal function. Of those with decreased renal function, serum arabinitol was elevated in 89, 92, and 50% of patients with Candida sepsis, Candida colonization, and bacterial sepsis, respectively. Of those with normal renal function, serum arabinitol was elevated in only 23 and 14% of patients with Candida sepsis and Candida colonization, respectively. When serum arabinitol/creatine ratios were calculated for patients with both increased arabinitol and increased creatinine, elevated ratios were obtained in 69, 36, and 0% of patients with Candida sepsis, Candida colonization, and bacterial sepsis, respectively.

Candidiasis↗
PubMed1982

Hematological changes following a marathon race in male and female runners.

The subjects of this experiment were well-trained men (6) and women (4) participating in a marathon race in Phoenix, Arizona, on a cool, cloudy, windy day. Venous blood was collected one week prior to the run, immediately after, and 4, 8, and 24 h after the race. There were no significant changes in hematocrit, hemoglobin, or red blood cell counts following the race. The sample collected immediately after the race showed a pronounced leucocytosis. Differential counts showed that this increase in white blood cell count was limited to polymorphonuclear cells, suggesting that an inflammatory response to stress of the race was involved. Percentage changes in blood volume, red blood cell volume, and plasma volume were calculated from hematocrit and hemoglobin changes. These changes showed that there was reduction of plasma volume of 8% for females and 13% for males immediately after the race, with return to initial values within 8 h. We suggest that the increase in protein following the race was contributed by the flow of lymph from muscle to the vascular compartment.

Adult↗
PubMed1982

Resistance of mice with limited intestinal flora to enteric colonization by Clostridium botulinum.

Infant botulism is an age-dependent illness that is caused by the toxin produced by Clostridium botulinum infecting the intestinal tract. Because of composition of the intestinal microflora determines the resistance of mice to enteric colonization by C. botulinum, attempts were made to identify the kinds of bacteria that prevent this in vivo growth. Orogastric challenges of 50 spores of C. botulinum type A were given to adult germfree mice, which are highly susceptible, and to gnotobiotic adult mice carrying the eight species comprising the Charles River Altered Schaedler flora or two or three of the limited number of species constituting a different flora (the University of Wisconsin Gnotobiote Laboratory [UW-GL] flora). These floras did not prevent infection due to C. botulinum; however, death rates among the mice with defined floras were significantly lower than those among germfree mice exposed to C. botulinum. Botulinum toxin continued to be produced while animals surviving nearly lethal cases of botulism convalesced slowly but uneventfully. Gnotobiotic mice with the complete UW-GL flora were not infected when challenged with 10(5) spores of C. botulinum.

Animals↗