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Biomedical subjects

S C Edberg

Publications and source records attributed to S C Edberg.

At least 19 recordsLinked to original sources

Clinical and laboratory analyses of cytospin-prepared Gram stains for recovery and diagnosis of bacteria from sterile body fluids.

The smear of a clinical specimen provides essential laboratory information that is used to make therapeutic decisions. For this study, smears were made by centrifugation in a Beckman Microfuge 11 (Beckman Instruments, Palo Alto, Calif.) and in parallel by using a Cytospin 2 apparatus (Shandon Inc., Pittsburgh, Pa.). Of 350 consecutive body fluid specimens examined, 50 (14.0%) grew bacteria. Both methods were culture and smear positive for 24 (6.9%) specimens; 18 (5.1%) specimens were cytocentrifuge smear positive, culture positive, and high-speed centrifugation (HSC) negative; 3 (0.8%) were culture negative and positive by both smear methods; and 1 (0.2%) was HSC smear positive, culture positive, and cytocentrifuge negative. Seven (2.0%) specimens were culture positive and negative by both smear methods. Clinically, cytocentrifuge preparations showed greater sensitivity for culture-positive specimens and a closer correlation with the CFU per milliliter than HSC did, resulting in a greater ability to treat patients with specific therapies. In addition, analysts needed to examine only a 6-mm-diameter area on the slide, cells and microbes were somewhat larger and more regular in appearance, and smears stained more uniformly. Because of the increased clinical and laboratory utility of the cytocentrifuge, its use is recommended in clinical microbiology laboratories for all sterile body fluid specimens.

Bacteria

Serological cross-reactions between Escherichia coli O157 and other species of the genus Escherichia.

The antigenic relatedness of Escherichia coli O157 and four sorbitol-negative species of the genus Escherichia was examined. Isolates of Escherichia hermannii, E. fergusonii, E. vulneris, and E. blattae were tested in the tube agglutination assay by using polyclonal antisera and in the slide agglutination assay by using latex reagents. Only four isolates (17%) of E. hermannii exhibited serological cross-reactivity.

Cross Reactions

Pseudoepidemic of Nocardia asteroides associated with a mycobacterial culture system.

Nocardia isolations increased from 0.7 to 11.7/1,000 acid-fast bacillus and mycological cultures (P less than 0.000001). Only three isolations from one patient represented infection. Pseudoepidemic strain identity was confirmed by DNA fingerprinting; the isolate causing infection was distinct. The end of the pseudoepidemic was associated with changing the needle sterilizer and prolonging needle sterilization time on the BACTEC 460 machine. To our knowledge, this is the first reported Nocardia asteroides pseudoepidemic.

Cross Infection

Strongyloides stercoralis hyperinfection and central nervous system involvement in a patient with relapsing polychondritis.

Infections caused by Strongyloides stercoralis are not uncommon in the United States. Because of the many different manifestations of hyperinfection with this nematode, a high index of suspicion is essential, especially in immunocompromised patients, for whom such infections are frequently fatal. Patients originating from endemic areas and those who have traveled to such areas, even in the distant past, should have the possibility of strongyloidiasis evaluated before initiation of immunosuppressive therapy. Once considered, the diagnosis is not difficult and can be accomplished using readily available techniques and methods. Although thiabendazole has a high incidence of side effects and may not always eradicate infection, it remains the drug of choice for disseminated strongyloidiasis.

Aged

Assay for beta-glucuronidase in species of the genus Escherichia and its applications for drinking-water analysis.

Recently, Escherichia species other than Escherichia coli have been isolated from potable water. Environmental isolates as well as clinical isolates of E. adecarboxylata, E. blattae, E. fergusonii, E. hermannii, and E. vulneris were assayed for the enzyme beta-glucuronidase by using EC MUG medium and the Colilert system. None of the isolates were positive for the enzyme by either method.

Escherichia

Periodic acid-Schiff-positive organisms in primary cutaneous Bacillus cereus infection. Case report and an investigation of the periodic acid-Schiff staining properties of bacteria.

Primary cutaneous Bacillus cereus infection frequently presents as a single necrotic bulla on the extremity of an immunocompromised patient. In lesional biopsy specimens and smears, the large gram-positive rods of B cereus may be mistaken for Clostridium species. This is a potentially serious error, as Bacillus species are resistant to penicillin and other beta-lactam antibiotics. We studied a case in which large periodic acid-Schiff-staining organisms were seen in the biopsy specimen from a necrotic bulla on the finger of a neutropenic patient with diffuse large cell lymphoma. The tissue biopsy specimen subsequently yielded a pure culture of B cereus. Staining with periodic acid-Schiff was then performed on a series of bacterial species in human tissue and from smears of culture colonies. The following bacterial species were found to be consistently periodic acid-Schiff positive after diastase digestion: B cereus, Corynebacterium diphtheriae, Propionibacterium acnes, Klebsiella pneumoniae, and Micrococcus luteus.

Aged

A ten-year review of neonatal sepsis and comparison with the previous fifty-year experience.

Records have been kept prospectively in our institution since 1928 of all positive blood cultures taken from neonates. Using a modification of objective Centers for Disease Control criteria to define sepsis, we reviewed the records of all neonates with positive blood cultures for the years 1979 to 1988 inclusive and found 270 cases of sepsis. The sepsis rate for infants less than or equal to 30 days of age was 2.7 cases/1000 live births, with a mortality rate from sepsis of 15.9%. There was an increase in sepsis due to commensal species (CS) over the period (P less than 0.007). The number of infants in the nursery who developed sepsis when more than 30 days of age also increased (P less than 0.002), as did the rate of sepsis from CS in this group (P less than 0.001). Isolation of CS from the blood with fulfillment of the modified Centers for Disease Control criteria was associated with a 13.7% mortality rate, whereas isolation of CS without fulfillment was associated with a 4% rate (P less than 0.01).

Birth Weight

Enumeration of total coliforms and Escherichia coli from source water by the defined substrate technology.

Many water utilities are required to monitor source water for the presence of total coliforms, fecal coliforms, or both. The Colilert system, an application of the defined substrate technology, simultaneously detects the presence of both total coliforms and Escherichia coli directly from a water sample. After incubation, the formula becomes yellow if total coliforms are present and fluorescent at 366 nm if E. coli is in the same sample. No confirmatory tests are required. The Colilert system was previously assessed with distribution water in a national evaluation in both most-probably-number and presence-absence formats and found to produce data equivalent to those obtained by using Standard Methods for the Examination of Water and Wastewater (Standard Methods). The Colilert system was now compared with Standard Methods multiple-tube fermentation (MTF) for the enumeration of total coliforms and E. coli from surface water. All MTF tubes were confirmed according to Standard Methods, and subcultures were made to identify isolates to the species level. The Colilert system was found equally sensitive to MTF testing by regression, t test, chi-square, and likelihood fraction analyses. Specificity of the Colilert system was shown by the isolation of a species of total coliform or E. coli after the appropriate color change. The Colilert test can be used for source water samples when enumeration is required, and the benefits previously described for distribution water testing--sensitivity, specificity, less labor, lower cost, faster results, no noncoliform heterotroph interference--are applicable to this type of water analysis.

Chi-Square Distribution

Efficacy of beta-glucuronidase assay for identification of Escherichia coli by the defined-substrate technology.

In 1976, Kilian and Bulow described the association of beta-glucuronidase with the genus Escherichia (97% positive) and suggested that a beta-glucuronidase assay would be a useful identification test. Since that report, papers about the sensitivity and specificity of this enzyme for the identification of Escherichia coli from clinical sources, food, seawater, potable-water supplies, and various environmental sources have appeared. A study was undertaken to determine the efficacy and specificity of the defined-substrate technology beta-glucuronidase (Colilert) assay for the identification of this species from fecal samples. A total of 460 human, 105 cow, and 55 horse E. coli isolates were tested. Results showed 95.5% beta-glucuronidase-positive isolates in 24 h and 99.5% positive after 28 h of incubation. Only one E. coli isolate was negative. There were no significant differences in the percentage of beta-glucuronidase-positive isolates among the human or animal isolates. There were no non-E. coli isolates that were positive. All subjects carried beta-glucuronidase-positive E. coli.

Animals

Mycobacterium gordonae pseudoinfection associated with a contaminated antimicrobial solution.

At Yale-New Haven Hospital, 46 specimens submitted for mycobacterial culture during an 8-week period in 1989 were positive for Mycobacterium gordonae, a nontuberculous acid-fast bacterium (AFB) of low pathogenicity. The specimens were submitted from 34 patients who came from various inpatient and outpatient services. Four patients were begun on antimycobacterial therapy on the basis of an AFB isolate which was later identified as M. gordonae. Isolation of M. gordonae was associated with use of the BACTEC TB system (BACTEC TB; Becton Dickinson Diagnostic Instrument Systems, Towson, Md.) and an antimicrobial solution, BACTEC PANTA PLUS (PANTA; Becton Dickinson Diagnostic Instrument Systems). The manufacturer reported that two lots (B9K1 and C9K1) of PANTA kits containing a single production lot (N8C1) of PANTA, which had been shipped to 173 laboratories, had been contaminated with M. gordonae. A survey of mycobacteriology laboratories in the United States revealed that, during April to July 1989, the M. gordonae isolation rate was 5.8/1,000 AFB specimens processed at laboratories that did not use BACTEC TB, 11.4/1,000 AFB specimens at laboratories that used BACTEC TB but not the implicated lot of PANTA, and 23.5/1,000 AFB specimens at laboratories that used BACTEC TB and the lot of implicated PANTA. Intrinsic contamination of PANTA was attributed to ineffective sterilization of water used in the manufacturing process and was not detected prior to product shipment because cultures for AFB were not part of the quality control regimen. This episode emphasizes that clinical laboratories can detect pseudoepidemics promptly if they are alert to abrupt increases in isolation rates, especially of unusual or generally nonpathogenic organisms.

Anti-Bacterial Agents

Direct detection of group B streptococci from vaginal specimens compared with quantitative culture.

Determination of prenatal vaginal carriage of group B streptococci (GBS) is important in the management of newborns. A pronase extraction-latex particle agglutination method (Streptex; Wellcome Diagnostics, Dartford, England) was used to rapidly detect GBS species-specific antigen directly from vaginal specimens. It was compared with quantitative and broth enrichment cultures. A total of 434 vaginal swab specimens were obtained before delivery. GBS cultures were positive for 14.7% of the specimens (64 of 434). Colony counts ranged from 2 to greater than 10(6) CFU per swab. The sensitivities of the direct antigen analysis were 19% (12 of 64) for all cultures and 63% (12 of 19) for specimens heavily colonized with GBS (greater than 10(4) CFU per swab). The specificity of the antigen test was 99.7%, with only one false-positive. There were three false-negative tests with colony counts of greater than 10(6) CFU per swab. The predictive values were 92% for a positive antigen test and 88% for a negative antigen test. The direct immunochemical detection of GBS antigen can be useful in a population of heavily colonized women. Direct latex particle agglutination does not appear to be salutary for a lightly colonized population and does not appear to be able to replace either culture or antigen detection after growth amplification at this time.

Antigens, Bacterial

Measurement of constitutive L-pyrrolidonyl peptidase activity from Streptococcus and Enterococcus using tetrazotized 0-dianisidine.

The detection of L-pyrrolidonyl peptidase activity is extremely useful for the differentiation of Enterococcus species and Streptococcus pyogenes from other members of the family Streptococaceae. This analysis has generally been performed utilizing the hydrolyzable substrate L-pyrrolidonyl beta-naphthylamine. After the substrate was hydrolyzed, free beta-naphthylamine has been detected utilizing the reagent para-dimethylaminocinnamaldehyde. The cinnamaldehyde and naphthylamine reagents combined to form an orange color, much like the indole reaction. The use of the cinnamaldehyde reagent had several drawbacks however: color development was not sharp, and the reagent was difficult to produce, and it was not stable. A new indicator system employing tetrazotized 0-dianisidine was developed. An extremely deep burgundy colored complex resulted from the reaction between the new indicator and B-Naphthylamine. This diazo reagent showed excellent correlation with results obtained with para-dimethylaminocinnamaldehyde and yielded more objective, distinct endpoints. This inexpensive reagent can be utilized either in a liquid form or dried on paper discs.

Aminopeptidases

Relationship between infectious diseases and human blood type.

During the past eight decades, a large number of studies have examined the possible relationship between blood type and infection. Many publications reflect uncritical attempts to mathematically link unstratified or random data. The interaction of pathogen and erythrocyte membrane may reflect antigenic similarity, adhesion through specific receptors, or modulation of antibody response. Anthropological surveys suggest that the geographic and racial distribution of human blood groups reflects susceptibility of populations with specific blood types to the plague, cholera, smallpox, malaria and other infectious diseases.

Anthropology

National field evaluation of a defined substrate method for the simultaneous detection of total coliforms and Escherichia coli from drinking water: comparison with presence-absence techniques.

A defined substrate method was applied to drinking water to simultaneously enumerate total coliforms and total Escherichia coli directly from samples. After incubation at 35 degrees C for 24 h, the development of yellow in an initially colorless solution was specific for total coliforms; fluorescence at 366 nm in the same tube(s) or vessel demonstrated the presence of E. coli. No confirmatory or completed steps were necessary. Known as autoanalysis colilert (AC), this method was constituted as a presence-absence test and compared with the methods described in Standard Methods (SM) in the P-A format. Seven water utilities representing a wide geological and hydrological spectrum participated in the evaluation. A total of 702 split drinking water samples were analyzed. Of these, 358 were negative in both tests (SM- and AC-); 302 were positive (SM+ and AC+); and 42 were mixed (SM+ and AC-, 20; AC+ and SM-, 22). The overall agreement rate was 94%. Comparison of the SM and AC results by nonparametric statistics demonstrated no differences. Heterotrophic plate count bacteria exerted no discernible effect on the AC test. By subculture, each time the AC test was yellow, a total coliform was present; when the test was fluorescent, E. coli was isolated.

Colony Count, Microbial

Epidemiology of pharyngeal colonization of infants with aerobic gram-negative rod bacteria.

By using a selective medium, pharyngeal colonization with gram-negative rod (GNR) bacteria was determined in a cohort of 49 normal infants monitored from birth to 6 months of age. Culture swabs were diluted in 1 ml of saline for quantitation. The prevalence of GNR in the first 72 h of life was 8% and rose to 29% during the first month, 52% at 2.5 months, 67% at 4.5 months, and 62% at 6 to 7 months. Colonization was with substantial numbers of organisms, generally greater than 100 colonies per ml and frequently greater than 1,000 colonies per ml. The most common species were Klebsiella species, Escherichia coli, Enterobacter species, and Acinetobacter anitratus. Fewer infants who were breast fed rather than formula fed at the time of culture harbored GNR (26 versus 45%, P less than 0.05). The point prevalence of pharyngeal GNR colonization in our special care nursery was 12 of 47 (26%), which was found to be similar to that of age-matched normal infants. GNR carriage in normal infants does not appear to be a residual of organisms acquired at birth, and interpretations of GNR carriage in ill or hospitalized infants should be evaluated by comparison with these data in healthy infants.

Age Factors