Biomedical subjects
Publications and source records attributed to G W Counts.
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Of 1506 marrow transplant patients from 1980 through 1986 reviewed for risk factors for invasive candidal infection defined by positive blood cultures, biopsy, or histologic evidence of tissue invasion, 171 (11.4%) had invasive infection, with a significantly higher incidence in the more recent years of review; 40% (69 patients) had evidence of tissue-invasive disease without fungemia. Of 102 patients with fungemia, 45% had candidemia alone with a mortality of 39%. Mortality in patients with tissue involvement was 90% with or without fungemia. Factors that increased infection were age, acute graft-versus-host disease, and donor mismatch. Factors that decreased infection included conditioning with 12 Gy of fractionated irradiation and cyclophosphamide, transplantation for aplastic anemia, and more rapid engraftment. Among fungemic patients, the number of days of fungemia was a risk factor for tissue invasion while more rapid engraftment was protective.
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HR 756, a new parenteral cephalosporin that is beta-lactamase resistant, was tested against 271 bacterial isolates. Both agar and broth dilution testing were employed, using two media and two inoculum sizes of bacteria. Antibacterial activity of the drug was compared to that of cefamandole (CFM) and ceforanide (CFN). In agar, HR 756 was more active than CFM and CFN against all bacteria tested except isolates of Staphylococcus aureus, which were better inhibited by CFM. HR 756 exhibited some antipseudomonas activity in agar, although a marked inoculum effect was apparent. A comparison of median minimum inhibitory and bactericidal concentrations in broth showed again that HR 756 was the most active of these three drugs. HR 756 demonstrated enhanced antibacterial activity compared to CFM and CFN against bacteria sensitive to all three drugs as well as against more resistant isolates of Serratia marcescens, Enterobacter species, and indole-positive Proteus. As with other cephalosporins, results for most bacteria were affected by inoculum size, medium, and type of dilution test employed in in vitro studies.
A Corynebacterium species consistently resistant to all antibiotic therapy except vancomycin caused bacteremia in 32 of 284 (11%) marrow transplant patients. Twenty-one patients had colonization or infection before bacteremia. Twenty-six of the 32 patients were males, and males older than 16 years were infected significantly more often than females over 16, or than all patient under 16. A case-control study showed that infected patients had greater exposure to antibiotics; more often had failure of engraftment and persistent granulocytopenia; were in laminar air-flow rooms less often; and had greater inhospital mortality. Cultural surveillance showed that 17 of 42 marrow transplant patients were colonized with Corynebacterium species. Likelihood of colonization appeared related to age, sex, and duration of hospitalization. Prevalence of colonization in other populations was 1% in nonhospitalized healthy adults and 13% in adults in a general hospital. Corynebacterium species infections occur primarily in adult males with granulocytopenia, mucocutaneous defects, and receiving intensive antibiotic therapy.
An orthopedic surgeon in whom hepatitis B subsequently developed participated in operations on 49 patients in the two months preceding his illness. Thirty of these patients were available for subsequent clinical and serologic follow-up: five had positive reactions for antibody to hepatitis B surface antigen (anti-HBs) and one had a positive reaction for hepatitis B surface antigen (HBsAg) at the initial examination an average of 77 days after surgery. No new patients had either clinical or serologic evidence of hepatitis B during four months of subsequent follow-up (mean of 6.7 months after surgery). A control group of 56 orthopedic patients had a 25% prevalence of positive reactions for anti-HBs and negative reactions for HBsAg- this was not significantly different from the exposed group. The risk to patients of acquiring hepatitis B after surgical exposure in this setting from a surgeon is low.
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One hundred forty-two strains of Escherichia coli isolated from extraintestinal infections were examined for colicin V (ColV) and hemolysin (Hly) production. For comparison, 20 strains isolated from the feces of normal individuals and 12 enteropathogenic strains of E. coli were tested for these properties. Thirty-five to 59% of extraintestinal isolates were Hly+, but only one fecal strain was Hly+. Colicin V biosynthesis was found for 12% of blood culture isolates, 7% of urine culture isolates and 16% of the strains from other extraintestinal infections. None of the fecal isolates was ColV+. Selected strains were tested for virulence in 13-day-old chicken embryos; these same strains were tested for their ability to hemagglutinate chicken or human erythrocytes. Of 22 extraintestinal isolates, 13 (59%) killed greater than or equal to 60% of the embryos within 72 h. Only one of eight normal fecal isolates and two of three enteropathogenic strains tested were virulent. About 80% of the virulent strains were Hly+. The most striking finding, however, was the hemagglutination of human erythrocytes by virulent extraintestinal isolates. It seems possible that the hemagglutination property reflects a specific common adherence factor.
Laminar air flow isolation and decontamination procedures were evaluated in a prospective randomized study in patients with aplastic anemia or acute leukemia undergoing marrow transplantation from HLA-matched siblings. Patients transplanted in the laminar air flow group had significantly less septicemia and major local infections than did patients in the control group. Nineteen of 46 laminar air flow patients and six of 44 control patients are alive at present. In patients with aplastic anemia the survival was 13 of 17 in the laminar air flow group compared with four of 17 in the control group. In patients with acute leukemia the survival was six of 29 in the laminar air flow group versus two of 27 in the control group. These differences were not statistically significant. Death in both the laminar air flow and control groups was predominantly due to interstitial pneumonitis or recurrent leukemia, which were unaffected by isolation and decontamination.
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Cefazaflur was tested in vitro against 262 strains of bacteria. Inhibitory and bactericidal concentrations were determined with two inoculum sizes of bacterial cells in Mueller-Hinton broth and nutrient broth. Agar dilution studies also were performed. When tested in agar, 5.0 mug or less of cefazaflur per ml inhibited almost all strains of Staphylococcus aureus, Escherichia coli, Klebsiella, and Proteus mirabilis. The drug was less active against Enterobacter and indole-positive Proteus, and 7.5 mug of antibiotic per ml inhibited approximately two-thirds to one-fourth of the strains. A concentration of 50 mug of cefazaflur per ml was required for inhibition of the enterococci. There was negligible activity against Pseudomonas. The drug demonstrated less activity in broth than in agar, and a major inoculum effect was seen with some strains. For example, with a lower inoculum, 2.5 mug of cefazaflur per ml killed all strains of E. coli, whereas with the higher inoculum, 7.5 mug of cefazaflur per ml, inhibited 64% and killed only 8% of strains. The activity of the drug for some strains was greater in Mueller-Hinton broth; for others, it was greater in nutrient broth. There were considerable differences in the results of the broth and agar studies for some species when the same medium was employed. Because of differences in activity found with different media, inocula, and method of testing, an evaluation of the eventual usefulness of cefazaflur must await the results of in vivo studies.
Cefaclor, a new oral cephalosporin, was compared in vitro with cephalexin and cephradine against 233 organisms. Evaluations were performed in Mueller-Hinton and nutrient broth and agar using two inoculum sizes. In agar, cefaclor had greater antibacterial activity than either cephalexin or cephradine against isolates of Escherichia coli, Proteus mirabilis, Staphylococcus aureus, Klebsiella pneumoniae, and Salmonella typhi. All three drugs were relatively inactive against isolates of enterococci, Enterobacter species, and indole-positive Proteus. Cefaclor, however, did exhibit the greatest activity of the three antibiotics against these organisms. Although there was wide variability with respect to test parameters, the broth results generally paralleled the agar results. In nutrient broth a clear separation of the results with these three cephalosporins was seen with K. pneumoniae, E. coli, and S. typhi. Cefaclor was the most active, cephalexin had intermediate activity, and cephradine was the least active. From the data obtained in this in vitro study, it can be concluded that cefaclor, which has a substituted chloro group attached to the molecule, had increased antibacterial activity over cephalexin and cephradine. Comparative clinical trials with cefaclor will determine whether the differences outlined above are of clinical significance.
Agar plates containing antiserum against group B meningococcus or Haemophilus influenzae type b were used to determine the prevalence of cross-reacting K1 and K100 capsular polysaccharide antigens in 265 isolates of disease-causing Escherichia coli. K1 antigen was found in 22% of isolates from various sites. K100 antigen was found in only three isolates. This technique is a convenient method to detect specific E. coli K antigens for evaluation as possible factors important in the virulence of the organism.
An outbreak of staphylococcal bacteremia in healthy, full-term neonates occurred in the newborn nursery at a large county hospital not employing prophylactic hexachlorophene bathing. Seven infants had staphylococcal bacteremia and one had omphalitis. Two of the three isolates obtained for phage typing were type 86, and the other was 3c/71. Staphylococcal colonization rate in the nursery was 64% when the outbreak was recognized; 86% of these isolates were type 86. No predominant phage type was isolated from nursery personnel. The outbreak followed a six-month preliminary study that showed a rise in staphylococcal colonization rate from 2.2% with hexachlorophene bathing to 67% with a nonhexachlorophene-containing preparation. In a community survey of infants born during the two months prior to the epidemic, seven of eight babies with lesions were infected with Staphylococcus aureus type 86.
An extensive outbreak of waterborne typhoid fever occurred in 1973 at a migrant labor camp in Dade County, Florida. Blood cultures from 105 of the 188 patients with proved or presumptive cases of typhoid fever grew Salmonella typhi. The clinical and laboratory findings in these patients were reviewed. Fever, usually with temperatures above 38.8 degrees C and of the sustained type, was a primary manifestation of disease, although a majority of the patients also complained of headache and gastroenteric symptoms. Hepatic or splenic enlargement was present in 52 per cent and 42 per cent, respectively, whereas rose spots were detected in only 13 per cent. The total leukocyte count was normal in 74 per cent, but serum levels of liver and muscle enzymes were frequently elevated. Gastrointestinal, pulmonary and neurologic complications were infrequent; circulatory failure was not observed. Defervescence in response to antibiotic therapy was variable; however, the median response among 68 patients who received chloramphenicol was two days less than that in 34 patients treated with ampicillin. There was one possible treatment failure with ampicillin. The relapse rate of 10 per cent in chloramphenicol-treated patients was not significantly greater than the 3 per cent rate among those treated with ampicillin. Serologic studies for typhoid fever were of limited diagnostic value since the titer of agglutinins was 1:160 or higher in 49 per cent of the serums obtained before treatment, and a fourfold rise in titer occurred in only 24 per cent of 57 patients studied. The serologic response to chloramphenicol treatment did not differ from that to ampicillin.
Six hundred twenty orthopedic surgery patients were evaluated in a prospective study of postoperative infection. The wound infection rate among the 378 elective clean procedures was 5.8 per cent (3.2 per cent major plus 2.6 per cent minor infections). Staphylococcus aureus was the single most common pathogen recovered in both major and minor infections. Gram-negative rods predominated in major infections, but were rarely found in minor infections. In the clean procedure group, infection rates increased with age and duration of operation. Preoperative consideration should be given to all A "profile sheet" or checklist of several such factors is presented for this purpose.
Cefoxitin is active in vitro against beta-lactamase-producing strains of Neisseria gonorrhoeae; therefore, its efficacy in the treatment of uncomplicated genital gonorrhea was evaluated in a study of ten men and 15 women. Cefoxitin was administered in two intramuscular doses given 5 hr apart, patients alternately receiving either 1 g or 2 g of cefoxitin in each injection. Probenecid (1 g) was administered orally with both injections to five women, and with the first injection only in the remaining patients. All cases of gonococcal cervicitis or urethritis were cured, and all rectal carriage was eliminated. Four of seven patients had persistent oropharyngeal carriage after treatment. There was no discernible difference between the efficacies of the 1-g and 2-g regimens. It was concluded that the cefoxitin regimens used are effective for therapy of uncomplicated genital or anorectal gonorrhea, but not for eradication of oropharyngeal carriage of N. gonorrhoeae.