bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of monoclonal antibody and calcofluor white stains for the detection of Pneumocystis carinii from respiratory specimens
Authors: Stratton N , Hryniewicki J , Aarnaes S L , Tan G , de la Maza L M , Peterson E M
Published: January 2020

Three monoclonal antibody staining kits, from Genetic Systems, Disease Detection International, and Meridian Diagnostics, were compared with calcofluor white for the direct detection of Pneumocystis carinii in respiratory specimens. Of the 150 specimens tested, 23 were found positive for P. carinii by any of the four stains; 13 were bronchoalveolar lavage, 7 were induced sputum and 3 were expectorated sputum specimens. All stains detected the positive bronchoalveolar lavage specimens, the Genetic Systems stain detected six induced sputum specimens, and the other stains each detected four induced sputum specimens. The monoclonal antibody stains detected all three expectorated specimens, while the calcofluor stain detected only one. Overall, the sensitivities of the stains were 96% for Genetic Systems, 87% for both Disease Detection International and Meridian Diagnostics, and 78% for calcofluor.
Comparison of standard culture methods, a shell vial assay, and a DNA probe for the detection of herpes simplex virus
Authors: Seal L A , Toyama P S , Fleet K M , Lerud K S , Heth S R , Moorman A J , Woods J C , Hill R B
Published: January 2020

A nonradioactive, biotinylated herpes simplex virus (HSV) DNA probe, a shell vial (rabbit kidney cell) culture assay enhanced by a direct fluorescent (HSV monoclonal)-antibody stain at 16 to 20 h postinoculation, and conventional tube cultures with confirmation via HSV-specific (polyclonal antibody) immunoperoxidase assay were compared for 199 specimens. The predictive values of the positive results were 54.5% for the probe, 95.9% for the shell vial assay, and 100% for the conventional culture methods, while the predictive values of the negative tests were 68.1, 84.0, and 98.4%, respectively. We conclude that the DNA probe (sensitivity, 24.5%; specificity, 88.3%) and the shell vial assay (sensitivity, 66.2%; specificity, 98.4%) cannot be substituted for conventional tube culture techniques (sensitivity, 97.1%; specificity, 100%) in the routine identification of HSV in our laboratory.
Comparison of flow cytometry and virus isolation in cell culture for identification of cattle persistently infected with bovine viral diarrhea virus
Authors: Qvist P , Houe H , Aasted B , Meyling A
Published: January 2020

Detection of bovine viral diarrhea virus in 143 blood samples by virus isolation in cell culture and flow cytometry was performed. The material included 37 samples later shown to originate from persistently infected cattle. Thirty-three samples were positive by virus isolation, and all 37 samples were positive by the flow cytometric assay.
Sampling efficiency in the diagnosis of Helicobacter pylori infection and chronic active gastritis
Authors: Nedenskov-Sørensen P , Aase S , Bjørneklett A , Fausa O , Bukholm G
Published: January 2020

The methods and sampling procedures used in the diagnosis of Helicobacter pylori infection and chronic active gastritis were evaluated. Five biopsy specimens for bacteriological cultivation and three specimens for histological examination were obtained endoscopically from a defined area of the gastric antral mucosae of 83 patients. An increase in the number of biopsy specimens for cultivation from one to five revealed only one more H. pylori-infected patient. H. pylori was isolated from 31 of 83 patients. Three technically adequate samples for histological examination were obtained from each of 74 patients. Of these 74 patients, chronic active gastritis was diagnosed by demonstration of typical histological changes in all three specimens from each of 20 patients, in two of three specimens from each of 3 patients, and in one of three specimens from 1 patient. The results indicate that one biopsy specimen is sufficient for the isolation of H. pylori, whereas several specimens may be necessary for the histological diagnosis. Chronic active gastritis was found in four patients not infected with H. pylori; on the other hand, H. pylori was isolated from nine patients who showed no signs of chronic active gastritis in any of three samples.
Candida albicans biotypes in human immunodeficiency virus type 1-infected patients with oral candidiasis before and after antifungal therapy
Authors: Bruatto M , Vidotto V , Marinuzzi G , Raiteri R , Sinicco A
Published: January 2020

A prospective 19-month study of 26 human immunodeficiency virus type 1-infected patients with episodes of erythematous or pseudomembranous oral candidiasis was done to evaluate the significance of Candida albicans biotypes in patients treated with antifungal therapy. Changes in the biotype of C. albicans were frequently noted in recurrent oral candidiasis. However, no correlation was found between the various biotypes and the clinical features of oral candidiasis, the clinical stage of human immunodeficiency virus type 1 infection, or the number of CD4+ lymphocytes. On the contrary, a significant correlation appeared among clinical lesion features, CD4+ cell numbers, and time of clinical disappearance of the oral lesions. Changes in the biotype of C. albicans were observed at the end of the antifungal therapy in 17 of 26 patients who had a second appearance of oral candidiasis as well as in 10 of 14 subjects who experienced a third reappearance of oral candidiasis.
Identification of Staphylococcus species and subspecies with the MicroScan Pos ID and Rapid Pos ID panel systems
Authors: Kloos W E , George C G
Published: January 2020

The accuracies of the MicroScan Pos ID and Rapid Pos ID panel systems (Baxter Diagnostic Inc., MicroScan Division, West Sacramento, Calif.) were compared with each other and with the accuracies of conventional methods for the identification of 25 Staphylococcus species and 4 subspecies. Conventional methods included those used in the original descriptions of species and subspecies and DNA-DNA hybridization. The Pos ID panel uses a battery of 18 tests, and the Rapid Pos ID panel uses a battery of 42 tests for the identification of Staphylococcus species. The Pos ID panel has modified conventional and chromogenic tests that can be read after 15 to 48 h of incubation; the Rapid Pos ID panel has tests that use fluorogenic substrates or fluorometric indicators, and test results can be read after 2 h of incubation in the autoSCAN-W/A. Results indicated that both MicroScan systems had a high degree of congruence (greater than or equal to 90%) with conventional methods for the species S. capitis, S. aureus, S. auricularis, S. saprophyticus, S. cohnii, S. arlettae, S. carnosus, S. lentus, and S. sciuri and, in particular, the subspecies S. capitis subsp. capitis and S. cohnii subsp. cohnii. The Rapid Pos ID panel system also had greater than or equal to 90% congruence with conventional methods for S. epidermidis, S. caprae, S. warneri subsp. 2, S. xylosus, S. kloosii, and S. caseolyticus. For both MicroScan systems, congruence with conventional methods was 80 to 90% for S. haemolyticus subsp. 1, S. equorum, S. intermedius, and S. hyicus; and in addition, with the Rapid Pos ID panel system congruence was 80 to 89% for S. capitis subsp. ureolyticus, S. warneri subsp. 1, S. hominis, S. cohnii subsp. urealyticum, and S. simulans. The MicroScan systems identified a lower percentage (50 to 75%) of strains of S. lugdunensis, S. gallinarum, S. schleiferi, and S. chromogenes, although the addition of specific tests to the systems might increase the accuracy of identification significantly.
Francisella tularensis-induced in vitro gamma interferon, tumor necrosis factor alpha, and interleukin 2 responses appear within 2 weeks of tularemia vaccination in human beings
Authors: Karttunen R , Surcel H M , Andersson G , Ekre H P , Herva E
Published: January 2020

Cell-mediated immunity is essential for protection against the intracellular bacterium Francisella tularensis, which causes tularemia. Positive in vitro T-cell responses in the form of lymphocyte proliferation and lymphokine interleukin 2 (IL-2) and gamma interferon (IFN-gamma) secretion are found in memory immunity. Studies on the secretion of lymphokines with regard to the developing immunity to F. tularensis have not been published. Therefore, 14 subjects with no clinical history of tularemia were vaccinated with a live F. tularensis vaccine strain. The in vitro responses of five subjects (antigen-induced mononuclear cell and whole blood culture DNA synthesis and cytokine secretion) were measured twice a week throughout the period from 0 to 35 days after vaccination, and the peripheral blood lymphocyte subpopulations of nine subjects were determined between days 0 and 14. Positive reactions, i.e., responses exceeding those on day 0, were reached on day 10 with regard to the whole blood culture DNA synthesis response and IL-2 and IFN-gamma secretion and on day 14 with regard to the mononuclear cell DNA synthesis response and tumor necrosis factor alpha (TNF-alpha) secretion. No measurable IL-4 was found in either the immune or nonimmune supernatants. Since the secretion of TNF-alpha was related to immunization, this points to the specificity of the phenomenon, even though the type of secreting cell is not yet known. If it is shown later that specific T cells produce it, the TNF-alpha response and the negative IL-4 finding may speak for the importance of the Th1-like pattern in immunity to F. tularensis.
Morphology of Borrelia burgdorferi: structural patterns of cultured borreliae in relation to staining methods
Authors: Aberer E , Duray P H
Published: January 2020

The microscopic recognition of Borrelia burgdorferi in biologic fluids and tissues is difficult and challenging because of low numbers of organisms occurring as single isolated spirochetes, the apparent lack of colony formation in tissues, and differing lengths and structural morphologies. To identify the most common morphologic forms, we studied numerous cultures by a variety of microscopic techniques. Culture suspensions of B. burgdorferi were stained by several different histochemical procedures (Gram, Wright, Wright-Giemsa, Giemsa, and polychromes), fluorochromes (thioflavin-T, acridine orange, and rhodamine), silver impregnation techniques (Warthin-Starry, modified Dieterle, modified microwave Dieterle, and Bosma-Steiner) and immunocytochemical methods with different polyclonal and monoclonal antibodies. Additionally, borrelia culture suspensions were embedded in agar and also injected into skin biopsies and processed for histologic study. The different staining properties were found to be influenced by fixation methods and the type of antibody in immunocytochemical stains. This study provides evidence for marked cytomorphic variations in individual spirochetes. Variations detected by these staining procedures provide a basis for future study of tissue sections and for how borreliae can be expected to appear in tissue sections.
Urea-induced release of heat-labile enterotoxin from Escherichia coli
Authors: Qu Z H , Boesman-Finkelstein M , Finkelstein R A
Published: January 2020

Urea induces the release of heat-labile enterotoxin (LT) from cells of LT-producing Escherichia coli strains. Optimal conditions were defined by using the checkerboard immunoblotting system. LT release was highest when E. coli cells were incubated in 8 M urea, pH 8.0, at 37 degrees C in a water bath for 30 min. Urea was more effective than polymyxin B in inducing the release of LT antigen from E. coli; the activity of LT from urea-treated cells was seven times that of LT from polymyxin B-treated cells. Urea also increased the antigenic and biological reactivities of purified LT. This procedure is potentially applicable for the detection of LT-producing E. coli strains in the clinical laboratory.
Identification of epidemic strains of Streptococcus suis by genomic fingerprinting
Authors: Mogollon J D , Pijoan C , Murtaugh M P , Collins J E , Cleary P P
Published: January 2020

A natural outbreak of Streptococcus suis meningitis in two closed swine herds was studied. DNA fingerprinting, serotyping, and biochemical profiles were assessed. Multiple serotypes were recovered from these herds. In farm A, 50 S. suis strains were isolated from 330 swabs collected. Eighteen strains belonged to serotype 2, and 32 strains belonged to serotypes 3, 5, 6, 8, 9, and 11. In farm B, 16 S. suis strains were recovered from a total of 70 samples. Eight strains belonged to serotype 7 and eight belonged to serotypes 2, 3, 5, and 8. In each epidemiological situation, a single strain characterized by a distinctive restriction fragment pattern predominated among affected penmates. The epidemic serotype 2 strain was detected in farm A in weaned pigs between the ages of 5 and 7 weeks. In contrast, the pathogenic strain in farm B belonged to serotype 7 and was isolated from pigs up to 3 weeks of age. The results from both farms strongly suggest a lateral spread of these organisms. No vertical transmission could be shown in either herd. It was concluded that genomic fingerprinting is an appropriate method to distinguish outbreak isolates of S. suis from nonoutbreak strains, within the same serotype or from epidemiologically unrelated clusters of strains.
Detection of human immunodeficiency virus type 1 by using the polymerase chain reaction and a time-resolved fluorescence-based hybridization assay
Authors: Dahlén P O , Iitiä A J , Skagius G , Frostell A , Nunn M F , Kwiatkowski M
Published: January 2020

The polymerase chain reaction (PCR) has many potential applications in the field of nucleic acid diagnostics. In particular, it has been successfully applied to the detection of pathogens present in low copy numbers such as the human immunodeficiency virus type 1. Here we describe a time-resolved fluorescence-based hybridization assay which, combined with the PCR, offers an extremely sensitive method for the detection of nucleic acids. In this assay format, the PCR is run by standard procedures and the subsequent hybridization reaction is carried out in solution by using two oligonucleotide probes, one biotinylated and one labeled with europium (Eu3+). The sandwich hybrids are then collected onto a streptavidin-coated microtitration well, and the bound Eu3+ is measured in a time-resolved fluorometer. This assay is rapid, user friendly, and quantitative and lends itself to automation. The application of this assay to the detection of human immunodeficiency virus type 1 is described.
Serological follow-up of patients involved in a localized outbreak of leptospirosis
Authors: Lupidi R , Cinco M , Balanzin D , Delprete E , Varaldo P E
Published: January 2020

Eighteen patients involved in a localized outbreak of leptospirosis were subjected to a serological follow-up study over a 5-year period. Four distinct sets of sera from all patients and a fifth sample obtained from 10 of them were examined by the microscopic agglutination test (MAT) for demonstration of leptospiral antibodies. The test was carried out by using live leptospires from reference strains of 17 Leptospira interrogans serovars known to occur in Italy. In all cases, the highest titers of agglutinins were recorded against one or more of the three Australis group serovars tested (australis, bratislava, and lora). The highest antibody levels were reached soon after the acute phase of infection in some patients but only after some months in others. Titers then tended to recede with varying rapidity, but titers against the Australis group serovars were still detectable in some patients after 5 years. Coagglutinins against serovars of other serogroups were detected, generally at low levels, in the early sets of sera of most patients, but tended to disappear in the late-set sera. Specific immunoglobulin M (IgM) and IgG against the three Australis group serovars were determined in most serum samples from 16 patients by solid-phase enzyme immunoassay (EIA). In general, EIA titers were considerably lower than MAT titers, but there was a certain patient-to-patient variability in both the IgM/IgG ratio and the evolution and persistence of the two immunoglobulin classes. Since all the evidence indicated that the initial outbreak from a single source, the observed patient-to-patient variability in the progress of both MAT and EIA titers appeared to be attributable to factors inherent in the individual patients. Cross agglutination absorption tests, aimed at retrospectively determining to which of the Australis group serovars the outbreak-specific infecting strain belonged, were performed with six serum samples from different patients. Most absorbed sera seemed to originate from an australis or lora infection, but it was not possible to discriminate conclusively between the two serovars.
False resistance to imipenem with a microdilution susceptibility testing system
Authors: O'Rourke E J , Lambert K G , Parsonnet K C , Macone A B , Goldmann D A
Published: January 2020

Routine monitoring of antibiotic resistance at Children's Hospital, Boston, detected a dramatic increase in the prevalence of imipenem-resistant strains of Pseudomonas aeruginosa. Further studies documented that false resistance to imipenem was due, in part, to the loss of imipenem potency in customized MIC microdilution trays supplied by Sensititre Ltd. (West Sussex, United Kingdom). Recognition of the problem was delayed by use of the quality control standard recommended by the manufacturer, which were higher and broader than those suggested by the National Committee for Clinical Laboratory Standards.
Inverse correlation in nutritionally variant streptococci between the production of bacteriolytic activity and sensitivity to a Streptococcus pyogenes bacteriocinlike inhibitory substance
Authors: Tagg J R , van de Rijn I
Published: January 2020

Nineteen strains of nutritionally variant streptococci (NVS) were tested for bacteriolytic activity and for their production of and sensitivity to streptococcal bacteriocinlike inhibitory substances (BLIS). None appeared to produce BLIS. An inverse relationship was found between the sensitivity to BLIS and the production of bacteriolytic activity against Micrococcus luteus. All but one of the 14 Streptococcus defectivus isolates were sensitive to the BLIS of S. pyogenes P5, and these isolates were nonlytic. The five S. adjacens isolates were not sensitive to any BLIS tested, and all of these isolates displayed bacteriolytic activity. Sensitivity to the BLIS of S. agalactiae P3 separated the nonlytic S. defectivus strains into two categories.
Comparison of six media, including a semisolid agar, for the isolation of various Campylobacter species from stool specimens
Authors: Endtz H P , Ruijs G J , Zwinderman A H , van der Reijden T , Biever M , Mouton R P
Published: January 2020

A recently described semisolid blood-free selective motility medium (SSM) (J. Goossens, L. Vlaes, I. Galand, C. Van den Borre, and J. P. Butzler, J. Clin. Microbiol. 27:1077-1080, 1989) was compared with two charcoal-based selective media (charcoal-based selective medium [CSM] and modified charcoal cefoperazone deoxycholate agar [CCDA]), two blood-based media (Skirrow medium [SKM] and CampyBAP), and a passive, 0.65-microns-pore-size cellulose acetate membrane filter technique for the recovery of campylobacters from stools of patients with diarrhea. A total of 1,980 specimens were tested, 161 of which were found to be positive for campylobacters. Campylobacter jejuni was isolated in 148 specimens (91.9%), C. coli was isolated in 27 (7.5%), and "C. upsaliensis" was isolated in 1 (0.6%). After 72 h of incubation with a single medium, the cumulative percentages of Campylobacter-positive specimens isolated on CSM, CCDA, SKM, and SSM were 87, 83, 80, and 72%, respectively. The filter method alone enabled us to recover 61% of all campylobacters. The "C. upsaliensis" strain was isolated by this method only. The highest isolation rates were observed when two media, including CSM, were combined. The combination of CSM and SSM yielded the highest rates (96%), but these were not statistically different from the rates observed with combinations of CSM and SKM (94%) or of CSM and the filter method (91%). Extending the incubation time from 48 to 72 h led to an increase in the isolation rate regardless of the medium used (P less than 0.001). CSM and CCDA were the most selective media. SKM and CampyBAP appeared to be the most inhibitory media for the isolation of C. coli.
Characterization of serovars of the genus Leptospira by DNA hybridization with hardjobovis and icterohaemorrhagiae recombinant probes with special attention to serogroup sejroe
Authors: Van Eys G J , Gerritsen M J , Korver H , Schoone G J , Kroon C C , Terpstra W J
Published: January 2020

Recombinant DNA probes derived from genomic libraries of serovars hardjobovis and icterohaemorrhagiae were applied for the characterization of leptospires. Differences in hybridization signals in combination with the banding pattern appear to provide good characteristics for strain typing. The banding patterns were easy to distinguish, since the recombinant DNA probes hybridized with a limited number of fragments. They were also indicative of genomic relationships between serovars. The probes suggested the existence of four subgroups with extensive genomic homology within the serogroup Sejroe. A number of serovars outside the serogroup Sejroe showed genomic homology with these subgroups. Amplification with the polymerase chain reaction showed a correlation with the genomic homologies demonstrated by Southern analysis. Knowledge about genomic relationships between leptospiral strains, as revealed by Southern analysis, may lead to a more rational approach for primer selection for polymerase chain reaction or cloning of particular genes.
Aerococcus-like organism, a newly recognized potential urinary tract pathogen
Authors: Christensen J J , Vibits H , Ursing J , Korner B
Published: January 2020

During the last 10 to 15 years, Aerococcus-like organisms have been isolated from urinary tract specimens from hospitalized patients at Bispebjerg Hospital, Copenhagen, Denmark, with signs of urinary tract infection, and a single strain has been deposited at the National Collection of Type Cultures (NCTC 12142). An additional 63 isolates from the urine specimens of as many patients with suspected urinary tract infection have been identified from seven departments of clinical microbiology in Denmark. Clinical information indicates that this organism may be involved in urinary tract infection. These strains and ten previously collected strains, two of which were from blood cultures, were characterized phenotypically. By comparing the results with data on other gram-positive, catalase-negative cocci or coccobacillary organisms, the identified organisms seem to represent a separate taxon.
Prospective study of cytomegalovirus antigenemia in allograft recipients
Authors: Miller H , Rossier E , Milk R , Thomas C
Published: January 2020

A recently published technique for direct detection of cytomegalovirus (CMV) antigenemia was tested prospectively in 27 transplant recipients. Eighteen patients developed active CMV infections and 10 of the 18 experienced CMV syndrome. All of the infections were detected by classical virus isolation and/or serologic techniques. No antigenemia was demonstrated.
Unusual case of Aeromonas hydrophila endocarditis
Authors: Ong K R , Sordillo E , Frankel E
Published: January 2020

We describe a case of Aeromonas hydrophila endocarditis in a 66-year-old man with myelodysplastic syndrome and non-A, non-B hepatitis, The infection resolved with antibiotic therapy, but the patient succumbed to complications of his underlying illness. This is the second case of Aeromonas endocarditis reported in the world literature.
Gas-permeable lifecell tissue culture flasks give improved growth of Helicobacter pylori in a liquid medium
Authors: Secker D A , Tompkins D S , Alderson G
Published: January 2020

Experiments were conducted to investigate the microaerobic culture of Helicobacter pylori in a liquid medium by using gas-permeable Lifecell tissue culture flasks. Growth in Lifecell tissue culture flasks was 1.2 to 1.6 log units greater than that in glass control bottles. These results were comparable to those reported by the use of gyrated media.
Cellular fatty acid composition of Plesiomonas shigelloides
Authors: Chou S , Aldova E , Kasatiya S
Published: January 2020

The cellular fatty acid compositions of 29 strains of Plesiomonas shigelloides and 5 strains of Aeromonas hydrophila were studied. The cellular fatty acid compositions of all the Plesiomonas strains were identical and characterized by the presence of hexadecanoate (16:0) (33%), hexadecenoate (16:1) (28%), octadecenoate (18:1) (9%), and octadecanoate (18:0) (6%). The cellular fatty acid composition of A. hydrophila was similar to that of the Plesiomonas strains, except that the former contained an average of 25% 16:0, 29% 16:1, 12% 18:1, and 2% 18:0 acids compared with 33, 28, 9, and 6%, respectively, for the latter. The percentage ratios of 16:1 to 16:0 and 18:1 to 18:0 could be used to differentiate P. shigelloides from A. hydrophila. These ratios were 0.8 and 1.5 for the former and 1.2 and 6.0 for the latter.
Isolation of Enterococcus mundtii from normally sterile body sites in two patients
Authors: Kaufhold A , Ferrieri P
Published: January 2020

Enterococcus mundtii, a recently described nonmotile, yellow-pigmented enterococcal species, was isolated from a chronic thigh abscess and from operatively obtained sinus mucosa. It is emphasized that this species may be encountered in clinical specimens and that the correct species identification may be missed when commercially available identification systems are relied on.
Candida albicans colony identification in 5 minutes in a general microbiology laboratory
Authors: Dealler S F
Published: January 2020

A total of 381 fully identified yeast isolates were tested by the germ tube (GT) and Albistrip (Lab M Ltd., Bury, United Kingdom) methods, and the results were compared. As a test system for the identification of Candida albicans, the Albistrip showed two false-positive and two false-negative results, whereas the GT showed seven false-negative and no false-positive results. With the same methods, 736 yeast isolates from clinical samples were tested in a laboratory that did not specialize in mycology. In this second experiment, when the results of the tests disagreed, further identification was carried out with the API 20C Yeast Identification System (API-Biomerieux Ltd., Vercieu, France). When the statistics of the first experiment were used to justify the results, this second experiment showed the Albistrip to be 98% sensitive and 98% specific, whereas the GT was 98% sensitive and 95% specific.
Epidemiology of rotavirus serotypes in Melbourne, Australia, from 1973 to 1989
Authors: Bishop R F , Unicomb L E , Barnes G L
Published: January 2020

Fecal rotavirus strains collected between 1973 and 1989 from 943 children admitted with acute diarrhea to one hospital in Melbourne, Australia, were serotyped by using an enzyme-linked immunosorbent assay. The assay incorporated neutralizing monoclonal antibodies specific for VP7 of the four major human serotypes (1 through 4). A serotype could be assigned to 690 of 943 specimens (73.2%). Typeable strains comprised serotype 1 (72.5%), serotype 2 (6.8%), serotype 3 (2.9%), or serotype 4 (15.4%). Monotypes 1a and 1c comprised 52 and 44%, respectively, of serotype 1 strains. All serotypes and monotypes exhibited polymorphic genomic RNAs. Specimens reacting as mixed serotypes were rare (3.2%) and included intertypic strains (0.7%) and mixed infections (1.0%). Nontypeable strains for which an electropherotype could be determined appeared to be identical with typeable strains present concurrently in the community. Serotypes exhibited various epidemiological patterns. Serotype 1 strains were dominant except during three successive winters when 60 to 90% of the disease was caused by serotype 2. Serotype 4 strains showed an episodic pattern of appearance, recurring at peak incidence approximately every 3 years. Fecal rotavirus strains collected from 145 newborn babies housed in Melbourne obstetric hospitals between 1974 and 1986 were also serotyped. All 135 typeable strains (93.1%) belonged to serotype 3. It is hypothesized that endemic infection with serotype 3 rotaviruses in nurseries for the newborn influenced the epidemiology of rotavirus serotypes responsible for severe clinical disease in young children in the same community.
Evaluation of the new RapID-ANA II system for the identification of clinical anaerobic isolates
Authors: Marler L M , Siders J A , Wolters L C , Pettigrew Y , Skitt B L , Allen S D
Published: January 2020

The RapID-ANA II System (Innovative Diagnostic Systems, Inc., Atlanta, Ga.) is a recently revised and marketed 4-h system for the identification of anaerobic bacteria. The system was compared with conventional identification methods for its ability to identify 566 clinical anaerobic isolates. Overall, the system identified correctly to genus and species 68% of the total isolates (62% of 204 gram-negative bacilli, 70% of 69 nonsporeforming gram-positive bacilli, 74% of 130 Clostridium isolates, and 72% of 163 anaerobic cocci), without the use of additional tests. With the additional tests suggested by the manufacturer, 78% of the total isolates were identified correctly to species. The routine use of a few simple and practical tests (e.g., egg yolk agar for Clostridium spp.), in addition to the RapID-ANA II, would improve significantly the accuracy of the system in the identification of anaerobic bacteria. This second-generation system offers a number of improvements over the original system, including an updated data base and the option of overnight refrigeration of the system before the addition of reagents.
Clinical comparison of the recoveries of bloodstream pathogens in Septi-Chek brain heart infusion broth with saponin, Septi-Chek tryptic soy broth, and the isolator lysis-centrifugation system
Authors: Murray P R , Spizzo A W , Niles A C
Published: January 2020

The recoveries of microorganisms in the Septi-Chek biphasic tryptic soy broth (TSB) and Isolator blood culturing systems were compared with the recovery in Septi-Chek biphasic brain heart infusion broth supplemented with the lytic agent saponin (L-BHIB; Roche Diagnostics, Division of Hoffmann-La Roche Inc.). A total of 5,096 TSB-L-BHIB blood culture sets and 1,778 Isolator-L-BHIB sets were evaluated. There were 435 pathogenic organisms recovered in 413 (8.1%) of the TSB-L-BHIB cultures, with 348 organisms in the TSB bottles and 370 in the L-BHIB bottles (P less than 0.05). Significantly more yeast isolates were recovered in the L-BHIB system (P less than 0.01). Terminal subculture of the L-BHIB system was required to detect 13 clinically significant organisms. Significantly more organisms were recovered in the L-BHIB bottles than with the Isolator system (P less than 0.001), including Torulopsis glabrata, coagulase-negative staphylococci, and Pseudomonas species. The time required for detection of all major groups of organisms was the same in both comparisons. However, detection of microbial growth in the L-BHIB bottles required macroscopic inspection of the attached agar slide unit and the use of terminal subcultures after 7 days of incubation. The primary advantage of the biphasic L-BHIB system when compared with either the biphasic TSB system or the Isolator system was improved recovery of fungi.
Effect of inoculum size on the phenotypic characterization of Campylobacter species
Authors: On S L , Holmes B
Published: January 2020

The type strains of six Campylobacter species or subspecies were examined in eight tests used for the identification of such organisms. False-positive results were obtained in certain tests (growth on 1% bile, brilliant green, selenite, trimethylamine-N-oxide, 2,3,5-triphenyl tetrazolium chloride, and minimal media) when an inoculum yielding 10(7) to 10(8) CFU/ml was used. Each tolerance test was examined with blood, nutrient, and brucella agars as basal media. The type of basal medium used could also affect the test outcome. With the inoculum standardized to a density yielding approximately 10(6) CFU/ml, reproducible and pertinent results were obtained, provided an appropriate basal medium was used. However, 95% confidence limits for viable counts done on these basal media indicated that blood agar may yield more consistent results than the other agars examined.
Detection of rubella virus gene sequences by enzymatic amplification and direct sequencing of amplified DNA
Authors: Eggerding F A , Peters J , Lee R K , Inderlied C B
Published: January 2020

We developed a rapid and sensitive polymerase chain reaction (PCR) assay for detecting and identifying rubella virus (RV). A segment of the RV gene which encodes the E1 membrane glycoprotein of RV was selected as a target for PCR amplification. Single-stranded viral RNA, extracted from infected cells or released from virions, was used as a template for reverse transcription followed by PCR amplification with two different sets of primer pairs, one nested within the other. The amplified E1 gene sequences were detected in ethidium bromide-stained agarose minigels, and their identities were verified by restriction enzyme digestion and hybridization to a probe directed at a site within the PCR target. Single-stranded DNA generated by asymmetric amplification of the target was directly sequenced by using fluorescent dideoxy-terminators and an automated procedure in order to confirm the target sequence. This PCR assay provides a rapid confirmatory test for the detection of RV by cell culture and appears to have considerable potential for the direct detection of RV in clinical specimens. The strategy used in the development of this PCR assay should be useful for developing other diagnostic PCR assays for viruses.
Spiral gradient endpoint method compared to standard agar dilution for susceptibility testing of anaerobic gram-negative bacilli
Authors: Hill G B
Published: January 2020

More efficient and reproducible alternative methods of performing agar dilution susceptibility testing are desirable, particularly for anaerobic bacteria. Anaerobes generally grow more reliably on solid media than they do in broth microdilution wells. A new method, the revised spiral gradient endpoint (SGE) method, was evaluated against the standard agar dilution (SAD) method by using a wide variety of anaerobic gram-negative bacilli (161 strains) and eight antimicrobial agents. For the SGE method, a spiral plater was used to set up a concentration gradient of an antimicrobial agent within an agar plate across which bacterial strains were inoculated as radial streaks. After incubation, the MIC of the antimicrobial agent was calculated from the radial endpoint location where bacterial growth ceased along the streak. The MICs for 90% of strains tested (in micrograms per milliliter) and the cumulative percentages of susceptible strains at the breakpoints for the SGE and SAD methods, respectively, and for all 161 strains were as follows: for metronidazole, 2 and 100 versus 2 and 100; for imipenem, 1 and 99 versus 0.5 and 98; for ampicillin-sulbactam, 8 and 97 versus 8 and 98; for clindamycin, 4 and 90 versus 4 and 91; for cefoxitin, 32 and 95 versus 32 and 95; for mezlocillin, 256 and 88 versus greater than 128 and 86; for ampicillin, greater than or equal to 256 and 51 versus greater than 64 and 51; and for penicillin (in units per milliliter), greater than or equal to 512 and 71 versus greater than 64 and 65. The excellent agreement of these data and the greater sensitivity reproducibility, and efficiency of the revised SGE method warrant further evaluations. Assuming that these advantages are confirmed, the revised SGE method should be a useful alternative test method when detailed susceptibility data are desired.
Cytopathogenic effects in enterocytelike Caco-2 cells differentiate virulent from avirulent Listeria strains
Authors: Pine L , Kathariou S , Quinn F , George V , Wenger J D , Weaver R E
Published: January 2020

We have developed a simple test that differentiates between virulent and avirulent Listeria species as defined by the mouse 50% lethal doses (LD50S). The assay is based on trypan blue-revealed cytopathogenic effects that are produced during the infection of the human enterocytelike cell line Caco-2. These effects were elicited only by Listeria strains that had an intraperitoneal mouse LD50 less than 10(8) and were not produced by nonhemolytic, avirulent strains of Listeria monocytogenes generated spontaneously or by Tn916 mutagenesis or by avirulent Listeria species. A negative test was also obtained with hemolysin-producing, avirulent L. monocyotogenes NCTC5105 and Listeria ivanovii KC1786. The test was negative with avirulent L. monocytogenes strains which are strong inducers of opacity in egg yolk agar. However, a strain which has a low LD50, such as 10(4), may show less severe cytopathogenic effects than a strain having a higher LD50, such as 10(6). The test has been effectively used to screen for virulent listerial isolates, spontaneous mutants, and transposon-induced mutants.
New aniline blue dye medium for rapid identification and isolation of Candida albicans
Authors: Goldschmidt M C , Fung D Y , Grant R , White J , Brown T
Published: January 2020

Organic dyes have long been used in diagnostic microbiology to differentiate species by color reactions. We studied the ability of a new noninhibitory medium, YM agar containing 0.01% aniline blue WS dye, Colour Index 42780 (YMAB), to identify Candida albicans among 1,554 yeast specimens obtained from seven clinical laboratories. Appropriate American Type Culture Collection and other characterized strains served as controls. A total of 487 of the clinical strains were identified as C. albicans. The remainder were other Candida species and non-Candida yeasts. Clinical isolates and controls were grown on Sabouraud agar for 18 h at 30 degrees C and then transferred to YMAB. Plates were incubated for 12 to 18 h at 30 degrees C, and colonies were observed for yellow-green fluorescence under long-wave UV light (A365). All control strains of C. albicans and Candida stellatoidea fluoresced, as did 480 of the 490 isolates designated as C. albicans (which included 3 strains of C. stellatoidea). Cells of C. albicans grown on YMAB produced germ tubes in serum. Only five of the other 1,062 non-C. albicans yeasts fluoresced. The sensitivity and specificity were 98.0 and 99.5%, respectively, with a predictive value of 99.1%. A fluorescent metabolite was found in cell wall particulate fractions of C. albicans sonic extracts grown on YMAB but not in non-C. albicans yeasts. This metabolite showed the same spectral curve as those of metabolites from whole cells in a recording spectrofluorometer when it was excited at 400 nm and scanned from 420 to 550 nm. Thus, growth on YMAB generates the production of a fluorescent moiety that can be used to specifically identify C. albicans within 12 to 18 h.
Evaluation of a recombinant human T-cell lymphotropic virus type I (HTLV-I) p21E antibody detection enzyme immunoassay as a supplementary test in HTLV-I/II antibody testing algorithms
Authors: Hartley T M , Malone G E , Khabbaz R F , Lal R B , Kaplan J E
Published: January 2020

To evaluate the usefulness of a human T-cell lymphotropic virus type I (HTLV-I) recombinant p21E immunoassay as a supplementary test in HTLV-I/II serologic testing algorithms, we used this assay to test 378 serum samples previously categorized as positive, indeterminant, or negative for HTLV-I/II antibody, as defined by U.S. Public Health Service guidelines. We found this test to be highly sensitive for detecting antibody to HTLV-I/II env (99.4%) but slightly less specific (96.0%), particularly among samples from intravenous drug users. Our data suggest that this test is most appropriately used to confirm the absence of env antibody in samples which are repeatably reactive in an HTLV-I/II screening assay and gag reactive only by immunoblotting. Because of the high sensitivity of this recombinant p21E test, a negative result in this context could preclude radioimmunoprecipitation testing. However, pending further evaluation of the specificity of this assay, samples testing positive for p21 env antibody may require confirmation by radioimmunoprecipitation, particularly in situations in which the results will be used for diagnostic purposes or blood donor counseling.
Typing of Chlamydia trachomatis by restriction endonuclease analysis of the amplified major outer membrane protein gene
Authors: Rodriguez P , Vekris A , de Barbeyrac B , Dutilh B , Bonnet J , Bebear C
Published: January 2020

A procedure was developed for characterization of Chlamydia trachomatis strains by using restriction endonuclease analysis of amplified genes of the major outer membrane protein (MOMP). Reference strains of the 15 serovars (A through K and L1 through L3) and clinical isolates were tested. The nucleotide sequences of the MOMP genes of each of the 15 serovars were arbitrarily constructed by using the sequences of the four variable domains known for each serovar and the constant domains of serovar L1. Computer analysis of these sequences indicated that two restriction digestions performed in parallel, one with AluI and the other with IIpaII, followed by HinfI and EcoRI, would allow the theoretical differentiation of 13 serovars. Serovars Ba and L1 presented the same theoretical restriction profile. Our typing method consisted of polymerase chain reaction amplification of a fragment of about 1,200 bp of the MOMP gene, followed by restriction endonuclease digestion with the aforementioned enzymes. From the 15 serovars, we obtained 14 different patterns; 13 profiles were serovar specific, while serovars B and Ba presented the same pattern. Application of this typing method to C. trachomatis strains isolated from clinical material gave the same results as the immunotyping method for 14 of 17 strains. Furthermore, restriction endonuclease analysis detected differences within a serovar. This method seems to be promising for epidemiological studies.
Evaluation of a commercially available enzyme-linked immunosorbent assay for Giardia lamblia antigen in stool
Authors: Addiss D G , Mathews H M , Stewart J M , Wahlquist S P , Williams R M , Finton R J , Spencer H C , Juranek D D
Published: January 2020

The lack of a quick, simple, and inexpensive diagnostic test has limited the ability of public health officials to rapidly assess and control outbreaks of Giardia lamblia in child day-care centers. We evaluated the performance of a commercially available enzyme-linked immunosorbent assay (ELISA) for the detection of a G. lamblia-associated antigen in stool. Stool specimens were collected from the diapers of 426 children attending 20 day-care centers, fixed in 10% Formalin and polyvinyl alcohol, and examined by microscopy by Formalin concentration and trichrome staining techniques. Specimens were also tested visually and spectrophotometrically by ELISA. Of 99 tests positive by microscopy, 93 were visually positive by ELISA (sensitivity, 93.9%). Of 534 tests negative for G. lamblia by microscopy, 32 (6.0%) were ELISA positive. However, on the basis of examination of multiple specimens from the same child, none of these could be considered false-positive ELISAs; the specificity of the ELISA was therefore 100%. The sensitivity of both microscopy and ELISA improved as the number of specimens per child increased. An optical density value of greater than 0.040 was 98.0% sensitive and 100% specific for G. lamblia. This ELISA, which appeared to be more sensitive for G. lamblia than did microscopic examination of stool, should be useful as an epidemiologic tool, particularly in day-care settings, and may also have a role in confirming clinical diagnoses of giardiasis.
Characterization of Gardnerella vaginalis and G. vaginalis-like organisms from the reproductive tract of the mare
Authors: Salmon S A , Walker R D , Carleton C L , Shah S , Robinson B E
Published: January 2020

Gardnerella vaginalis has been isolated from women with bacterial vaginosis, from the genital tracts of asymptomatic women, and from several other infected body sites in humans. However, until recently, it has not been isolated from any other animal species. Between June 1988 and October 1989, 31 isolates identified as G. vaginalis and 70 isolates identified as G. vaginalis-like organisms have been recovered from the genital tracts of 93 mares from Michigan and Ohio. Identification was based on biochemical reactions, hemolysis on media containing blood from various animal sources, and susceptibility to select antimicrobial agents. This report details the characterization of G. vaginalis and G. vaginalis-like organism isolates obtained from the reproductive tracts of these mares and compares the equine isolates with human isolates.
Genetic diversity and identification of human infection by amplification of the chlamydial 60-kilodalton cysteine-rich outer membrane protein gene
Authors: Watson M W , Lambden P R , Clarke I N
Published: January 2020

The 60-kDa cysteine-rich outer membrane protein genes of Chlamydia psittaci, Chlamydia pneumoniae, and Chlamydia trachomatis have very different 5' ends, but two areas flanking this variable region show absolute sequence conservation. This observation permitted differentiation of the three species of Chlamydia by the polymerase chain reaction (PCR), forming the basis of a diagnostic test for chlamydial infections. The PCR product containing the variable region of the respective 60-kDa CrP genes was also subjected to restriction endonuclease digestion, enabling differentiation of individual type strains of C. psittaci. Differentiation was possible between lymphogranuloma venereum and trachoma isolates of C. trachomatis. The PCR-based diagnostic test was successful with all strains of chlamydiae studied. The PCR primers showed high specificity and did not produce any product with common bacterial pathogens that may share the same sites of infection.
Detection of enterococcal high-level aminoglycoside resistance with MicroScan freeze-dried panels containing newly modified medium and Vitek Gram-Positive Susceptibility cards
Authors: Weissmann D , Spargo J , Wennersten C , Ferraro M J
Published: January 2020

Both conventional and modified MicroScan Type 5 panels and Vitek Gram-Positive Susceptibility cards were compared with agar dilution screen plates for their abilities to detect high-level resistance to gentamicin and streptomycin in 235 enterococcal isolates, including 167 Enterococcus faecalis and 63 E. faecium isolates. The modified Type 5 panels contained dextrose-phosphate broth instead of Mueller-Hinton broth in their high-level-resistance screen wells. The sensitivities for detection of gentamicin and streptomycin high-level resistance were 100 and 100% (E. faecalis) and 100 and 94% (E. faecium) for the modified MicroScan panels, 100 and 89% (E. faecalis) and 100 and 98% (E. faecium) for the conventional MicroScan panels, and 81 and 86% (E. faecalis) and 85 and 94% (E. faecium) for the Vitek cards. All specificities were 100% except for the Vitek cards with streptomycin, where it was 96%. Isolates that showed resistance on the streptomycin agar screen plates were rescreened on plates containing 32,000 micrograms/ml to detect ribosomally mediated resistance. For all three systems, every failure to detect streptomycin high-level resistance occurred in isolates with enzymatic, not ribosomal, resistance. The modified MicroScan Type 5 panels are a suitable method for detecting enterococcal high-level resistance to gentamicin and streptomycin. The Vitek cards are too insensitive for this purpose.