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Biomedical subjects

L B Reller

Publications and source records attributed to L B Reller.

16 recordsLinked to original sources

False-positive Gram-stained smears.

The rate per 1,000 smears showing nonviable Gram-negative bacilli (false-positive smears) increased from a baseline of 10.8 to 38.5 following purchase of new culture-collection devices; the rate decreased to 8.0 following replacement of contaminated culture sets. False-positive reports led to changes in therapy for five patients. In addition to being sterile, commercial culture-collection devices should be certified by the manufacturer as being free of stainable microorganisms or as unsuitable for preparation of Gram-stained smears.

Adolescent

Evaluation of preservative fluid for urine collected for culture.

Immediate culture or refrigeration of urine is recommended, but not always practical. Therefore, we evaluated the Becton-Dickinson Urine Culture Kit containing a boric acid-glycerol-sodium formate preservative in a study of 1,000 clinical urine specimens. Each specimen was cultured a total of four times by the surface streak technique with a 0.001-ml calibrated loop. After an initial reference culture (culture 1), a portion of urine was poured into a clean nonsterile paper cup, aspirated into a urine transport tube, and recultured immediately (culture 2). The original specimen cup was refrigerated for 18 to 24 h (culture 3), and the urine transport tube was held at room temperature for 18 to 24 h (culture 4) before repeat cultures. Eighty-eight of the initial reference cultures were positive (pure growth of greater than 10(5) bacteria per ml). Eighty-two (93.2%) of the 88 specimens positive on the reference culture were also positive after refrigeration or holding at room temperature in the transport tube for 24 h. There was one false-positive culture from refrigerated urine but none from the transport tube. Mixing of urine in a nonsterile container did not introduce detectable contamination. We conclude that the Becton-Dickinson Urine Culture Kit maintains a stable bacterial population in urine for up to 24 h as reliably as refrigeration. Urine for culture may be collected in a nonsterile container if it is immediately aspirated into the transport tube so that contaminants are not allowed to multiply.

Bacteria

Comparison of direct and standard antimicrobial disk susceptibility testing for bacteria isolated from blood.

To determine the reliability of early antimicrobial susceptibility testing, we compared the results of direct and standard single-disk diffusion methods for 581 positive blood cultures processed routinely by the clinical microbiology laboratory. The direct procedure differed from the standard one only in that the 0.5 McFarland inoculum was prepared from 1 ml of turbid broth rather than five isolated colonies from a subculture plate. A major discrepancy in results was defined as a change from susceptible to resistant or vice versa according to interpretive standards for zone diameters, whereas a minor discrepancy was defined as a shift to or from the intermediate category when paired direct and standard tests were compared. The overall agreement between the two methods was 94.6% of 2,308 comparisons. There were 119 minor (5.2%) and 6 major (0.3%) discrepancies. The major discrepancies were seen with three strains of Staphylococcus epidermidis and one strain each of S. aureus, Escherichia coli, and Enterobacter sp. Direct susceptibility testing of positive blood cultures that were pure by gram-stained smear provided reliable results 24 to 36 h earlier than conventional procedures; therefore, we recommended this procedure to guide early antimicrobial therapy in patients with bacterial sepsis.

Anti-Bacterial Agents

Campylobacter enteritis: clinical and epidemiologic features.

Campylobacter fetus subspecies (ssp.) jejuni has been recently recognized to cause diarrheal disease in man. To assess its importance as an enteric pathogen, we prospectively studied 514 patients with diarrhea. Campylobacter fetus ssp. jejuni was isolated from the feces of 26 patients (5%) and seven of 11 of their symptomatic household contacts. This organism was isolated from the feces of only one of 18 asymptomatic household contacts and not at all from 157 other healthy persons. Seventeen of 20 patients from whom C. fetus ssp. jejuni was isolated from fecal culture showed at least a fourfold rise in specific IgG titers. Review of 35 cases of campylobacter enteritis identified a typical clinical syndrome with acute onset of diarrhea, abdominal pain, fever, and constitutional symptoms. Stool examination revealed blood in 60% and polymorphonuclear leukocytes in 78% of patients. Epidemiologic investigation strongly suggested an external source for the infection in 22 of 35 patients.

Abdomen

Auricular sporotrichosis in a brick mason.

A case of cutaneous sporotrichosis involving the auricle of a brick mason is reported. Despite the infrequency of such an infection, sporotrichosis must be considered in the differential diagnosis of perichondritis. The occupational associations with Sporothrix schenckii are reviewed and the relationship with bricks is emphasized.

Adult

Successful treatment of Brucella melitensis end-carditis.

Brucella endocarditis is a rare, but often fatal, complication of brucellosis. A 32 year old man acquired brucellosis while on a visit to his former home in Greece and presented six months later with malaise, fever and aortic regurgitation. Blood cultures grew Brucella melitensis biotype 1. Combined chemotherapy with streptomycin, tetracycline and rifampin sterilized his blood; however, his aortic valve was replaced owing to recurrent emboli and cardiac failure. Over the next 18 months the patient's antibody titer to Brucella fell and his blood reamined sterile. Cure was achieved by resection of the infected aortic valve and 10 weeks of bactericidal therapy for B. melitensis.

Adult

Tuberculoid tenosynovitis and carpal tunnel syndrome caused by Mycobacterium szulgai.

Mycobacterium szulgai, a scotochromogenic mycobacterium, is a newly recognized pathogen of man and has been reported to cause pulmonary infections, olecranon bursitis and cervical adenitis. We isolated M. szulfai from granulomatous tissue removed at surgery from a young florist with the carpal tunnel syndrome. The organism was susceptible to ethambutol and rifampin but resistant to isoniazid. Cure was achieved by debridement and chemotherapy with ethambutol and rifampin. Neither the source in our patient nor the natural habitat of M. szulgai is known. Because it resembles M. gordonae and M. flavescens, common scotochromogenic mycobacteria in tapwater, care must be taken to avoid dismissing M. szulgai as a contaminant when it is isolated from tissue.

Adult

Susceptibility of Clostridium perfringens isolated from human infections to twenty antibiotics.

The proper choice of antibiotic for Clostridium perfringens infections in patients allergic to penicillin is not clear; the usual recommendations and recent in vitro studies disagree. We tested the susceptibility of 57 strains of C. perfringens to eight penicillins, seven cephalosporins, two tetracyclines, clindamycin, chloramphenicol, and rifampin by the agar dilution method. All strains were inhibited by (per milliliter) 4 mug or less of any of the penicillins, chloramphenicol, or clindamycin and 8 mug or less of any of the cephalosporins tested. Penicillin G and amoxicillin inhibited all strains at 0.12 mug or less per ml. Only 54% of the strains were inhibited by 1 mug of tetracycline per ml. Penicillin G remains the drug of first choice for infections with C. perfringens; it need not be added to a regimen containing a penicillinase-resistant penicillin given parenterally in high doses. The cephalosporins should be considered as alternative drugs for penicillin-allergic patients. Clindamycin and chloramphenicol are also effective. Tetracyclines cannot be depended upon in clostridial infections without in vitro testing, which is impracticable for initial empirical therapy.

Anti-Bacterial Agents

Limulus amebocyte lysate test in neonates.

The limulus amebocyte lysate test for endotoxin was done on samples of blood from 22 well babies and 33 neonates in an intensive-care nursery. The objective was to determine whether falsely positive test results occurred in samples from newborn infants during acquisition of usual bowel flora. One neonate had a transiently positive limulus amebocyte lysate test; he had clinical signs of spesis, but no bacteremia could be documented. Unlike the nitroblue tetrazolium test, the limulus amebocyte lysate test does not appear to be regularly positive in neonates. The sensitivity of the test in detection of endotoxemia associated with gram-negative spesis in the neonate remains to be determined in a large prospective study.

Arthropods

Shigellosis in the United States: ten-year review of nationwide surveillance, 1964-1973.

In the 10 years 1964-1973, 105,832 isolations of shigellae were reported to the Center for Disease Control through a nationwide surveillance system. The number reported increased by approximately 13% annually, from 5852 in 1964, when only 17 centers reported all 4 quarters; to 16,797 in 1973, when 52 centers reported each quarter. The rate of reported isolations varied from 4.6 per 100,000 persons in 1965 to 9.1 per 100,000 in 1973. Shigella sonnei accounted for 64% of all these isolates and for more than 80% of isolates in 1973. The majority of reported cases of shigellosis occurred in young children and in women of childbearing age. During the 10-year surveillance period, 35 epidemics in 25 states were investigated. Two-thirds of these outbreaks were the result of person-to-person spread; investigations of common-source outbreaks showed the importance of both water and foodstuffs, especially salads, as potential vehicles of contamination. Indian reservations, custodial institutions, and day-care centers were identified as special high-risk settings for the transmission of shigellosis. The emergence of R-factor-mediated antimicrobial-resistance patterns in recent years has necessitated antibiotic sensitivity testing to determine the drug of choice for treatment of individual cases. Initial testing of oral vaccines suggests these vaccines will have only limited usefulness in protecting certain high-risk populations. Public health education coupled with improvements in water and sewerage systems remains the most satisfactory means of control.

Adolescent