bluuebunny/crossref_metadata_2025 huggingface dataset:
Persistence of intestinal antibody response to heterologous rotavirus infection in a murine model beyond 1 year
Authors: Shaw R D , Merchant A A , Groene W S , Cheng E H
Published: January 2020

We used an ELISPOT (enzyme-linked immunosorbent spot) assay to quantitate the long-term rotavirus-specific intestinal antibody response in a murine model. The frequency of murine intestinal antibody-secreting cells (ASCs) was followed for a period of 1 year after a single dose of rhesus rotavirus (10(6) PFU) was administered at 10 days of age. Some animals were boosted at that time with a second dose. One year after infection, virus-specific ASCs declined from acute-phase levels, but they were still present at significant levels (1.32 x 10(4) virus-specific ASCs per 10(6) intestinal mononuclear cells; approximately 17% of the previously reported response at 1 month after infection). A booster dose 1 year after the primary infection produced a 100% increase in virus-specific ASCs but did not restore the response to that of the primary infection.
Cryptosporidiosis: multiattribute evaluation of six diagnostic methods
Authors: MacPherson D W , McQueen R
Published: January 2020

Six diagnostic methods (Giemsa staining, Ziehl-Neelsen staining, auramine-rhodamine staining, Sheather's sugar flotation, an indirect immunofluorescence procedure, and a modified concentration-sugar flotation method) for the detection of Cryptosporidium spp. in stool specimens were compared on the following attributes: diagnostic yield, cost to perform each test, ease of handling, and ability to process large numbers of specimens for screening purposes by batching. A rank ordering from least desirable to most desirable was then established for each method by using the study attributes. The process of decision analysis with respect to the laboratory diagnosis of cryptosporidiosis is discussed through the application of multiattribute utility theory to the rank ordering of the study criteria. Within a specific health care setting, a diagnostic facility will be able to calculate its own utility scores for our study attributes. Multiattribute evaluation and analysis are potentially powerful tools in the allocation of resources in the laboratory.
Comparison of polymerase chain reaction with culture and serology for diagnosis of murine experimental Lyme borreliosis
Authors: Pachner A R , Ricalton N , Delaney E
Published: January 2020

After the intradermal inoculation of mice with Borrelia burgdorferi, the antibody response, culture, and histology of blood and target organs were assessed and compared with results of a nested polymerase chain reaction (PCR) assay. Of 247 specimens of heart, brain, bladder, and blood, the tested concordance between the PCR and culture was 72%. In the 69 instances of discordance, the PCR was positive in 51 and the culture was positive in 18; thus, the PCR was concordant or more sensitive in 93% of the tested organs. In mice infected with 10 spirochetes, serology confirmed by Western blotting (immunoblotting) was more sensitive than either culture or PCR of brain, bladder, or heart specimens. The organs most commonly culture or PCR positive were the heart and bladder; the brain was infected in only 26% of the animals. DNA hybridization was helpful in confirming the PCR product as being specific and, in some cases, in demonstrating a positive product in the face of negative agarose gels. PCR was less sensitive than culture in detecting the presence of spirochetes in blood specimens, possibly because of the presence of blood inhibitors. We thus found a nested PCR assay, using primers from a genomic sequence, to be a valuable adjunct to serology and culture in the study of murine Lyme borreliosis. The assay confirmed that, after small numbers of spirochetes are injected intradermally, the heart and bladder, and less frequently the brain, are sites of persistence of the spirochetes.
Ribotype analysis of Pseudomonas pseudomallei isolates
Authors: Sexton M M , Goebel L A , Godfrey A J , Choawagul W , White N J , Woods D E
Published: January 2020

No epidemiological typing system to differentiate among Pseudomonas pseudomallei isolates has been available. Ribotype analysis was developed and used to examine 74 clinical and 10 environmental isolates of P. pseudomallei from Thailand. Six P. pseudomallei ribotypes were identified from restriction fragment polymorphisms of EcoRI chromosomal digests. The predominant ribotype, A, was found in 59 of the isolates examined. By using patterns from hybridizations with SalI, HindIII, and PstI restriction digests, isolates of ribotype A were subdivided into a further five subtypes, giving a total of 10 differentiable P. pseudomallei types. In 23 of 34 melioidosis patients studied, multiple P. pseudomallei isolates were present. In all but one of these patients, a single ribotype of the organism was present. Isolation of two different ribotypes of P. pseudomallei from one patient, one each in sputum and urine, suggests that superinfection may have occurred. The ribotype was shown to be conserved during the course of antibiotic treatments in seven patients studied, although the antibiotic sensitivity patterns in the isolates from these patients varied. The prevalence of subtype A1 in clinical and environmental specimens suggests that this strain may be predominant in this geographical location. These results demonstrate the usefulness of the ribotyping method for epidemiological studies of P. pseudomallei.
Molecular characterization of a novel repetitive element from Pneumocystis carinii from rats
Authors: Zhang J , Cushion M T , Stringer J R
Published: January 2020

A repetitive DNA sequence, Rp-alpha, was isolated from rat-derived Pneumocystis carinii. The genome of rat-derived P. carinii contained 10 to 15 copies of Rp-alpha, which were located on most chromosomes, but no Rp-alpha could be detected in P. carinii derived from either humans or mice. Sequence analysis of two copies of the repeat showed them to be related but distinct. Each of them contained several copies of the 9-base sequence TAACCCTAA, arranged as direct repeats. Oligonucleotides consisting of multimers of this 9mer hybridized to the same set of chromosomes recognized by cloned copies of the Rp-alpha repeat. When used in DNA fingerprinting, the Rp-alpha repeat was capable of distinguishing between different isolates of rat-derived P. carinii.
Enzymatic reactions of Clostridium difficile in aerobic and anaerobic environments with the RapID-ANA II identification system
Authors: Peiffer S , Cox M
Published: January 2020

The RapID-ANA II anaerobic identification system (Innovative Diagnostic Systems, Inc., Atlanta, Ga.) was used to determine whether the incubation environment affects enzyme detection. Twenty strains of Clostridium difficile were tested in aerobic, anaerobic, and low-CO2 anaerobic incubation environments. The percentages of enzymes detected in reactions with the following substrates were noted in the three incubation environments: phenylalanine-beta-naphthylamide, aerobic, 0%; anaerobic, 35%; low-CO2 anaerobic, 35%; arginine-beta-naphthylamide, aerobic, 5%; anaerobic, 55%; low-CO2 anaerobic, 75%; pyrrolidonyl-beta-naphthylamide, aerobic, 5%; anaerobic, 65%; low-CO2 anaerobic, 65%. When the aerobic incubation environment was compared with either the anaerobic or the low-CO2 anaerobic incubation environments, the results were statistically different with respect to enzyme detection in reactions with the substrates listed above. The results for the anaerobic and low-CO2 anaerobic environments were not statistically different. The study was repeated twice. Statistical comparisons between the three environments were consistent with the results presented above, with the following exceptions. The aerobic and the anaerobic environments were not different in a reaction with phenylalanine-beta-naphthylamide in one of the runs, and there was no significant difference between the three environments in a reaction with arginine-beta-naphthylamide in another run. These results suggest that some of the enzymes used in the identification of clinical anaerobes appear to be inactive in an environment containing oxygen.
Detection of plasma viremia in human immunodeficiency virus-infected individuals at all clinical stages
Authors: Pan L Z , Werner A , Levy J A
Published: January 2020

Free virus (virus not present within cells) was detected in the plasma of all human immunodeficiency virus (HIV)-infected individuals studied. Plasma samples from asymptomatic individuals and individuals with HIV disease were tested. The levels of virus varied, but high virus titers correlated directly with HIV-related symptoms and low CD4+ lymphocyte counts. Effective detection of infectious virus depended on the use of an enzyme-linked immunosorbent assay for p24 core antigen and culture conditions in which plasma was added to mitogen-stimulated lymphocytes within 3 h of venipuncture. When there were delays in the time to culturing of plasma, neutralizing antibodies and perhaps other factors present in the plasma were found to reduce the efficiency of virus recovery. Plasma stored at -70 degrees C for several months maintained a stable level of free virus. These results suggest that measurement of HIV present in plasma under optimal conditions could be an efficient way of monitoring the clinical state of an individual and the effects of antiviral therapy.
Comparison of four decontamination methods for recovery of Mycobacterium avium complex from stools
Authors: Yajko D M , Nassos P S , Sanders C A , Gonzalez P C , Reingold A L , Horsburgh C R , Hopewell P C , Chin D P , Hadley W K
Published: January 2020

The presence of Mycobacterium avium complex (MAC) in stool specimens may be a predictor of disseminated MAC infection, yet the methods for decontaminating stools have not been evaluated for their usefulness in recovering MAC organisms. In the present study, four decontamination methods commonly used to recover acid-fast bacteria from respiratory specimens were compared for their utility in recovering MAC from stool specimens. Ten strains of MAC were used at a level of 10(4) to 10(6) CFU to seed the stool specimens. Specimens were divided into four portions and were decontaminated by using the following treatments: (i) N-acetyl-L-cysteine-sodium hydroxide (NALC-NaOH), (ii) cetylpyridinium chloride-sodium chloride (CPC-NaCl), (iii) oxalic acid, or (iv) benzalkonium chloride-trisodium phosphate (BC-TSP). The specimens were then plated onto a total of five pieces of selective and nonselective egg- and agar-based media. The oxalic acid method yielded the greatest number of MAC CFU from seeded stool samples; this was followed by NALC-NaOH, BC-TSP, and CPC-NaCl. The difference between the oxalic acid method and each of the other methods was statistically significant (analysis of variance at the 95% significance level). Although more MAC CFU was recovered from seeded stool samples by using oxalic acid than NALC-NaOH, no difference in culture positivity rates was observed when the two methods were used to test 368 clinical stool specimens processed with either oxalic acid (164 specimens) or NALC-NaOH (204 specimens) (P = 0.07) or 67 specimens processed by both methods (P = 0.77). The oxalic acid and NALC-NaOH decontamination methods both appear to be useful for the recovery of MAC organisms from stool specimens.
Evaluation of intestinal protozoan morphology in polyvinyl alcohol preservative: comparison of zinc sulfate- and mercuric chloride-based compounds for use in Schaudinn's fixative
Authors: Garcia L S , Shimizu R Y , Shum A , Bruckner D A
Published: January 2020

As a result of disposal problems related to the use of mercury compounds, many laboratories have considered switching from mercuric chloride-based Schaudinn's and polyvinyl alcohol (PVA) stool preservatives to other non-mercury-based preservatives. The primary use for PVA-preserved specimens is the permanent stained smear, the most important technique in the routine ova and parasite examination for the identification and confirmation of intestinal protozoa. A comparison of organism recovery and morphology of the intestinal protozoa was undertaken with PVA containing either a zinc sulfate base or the "gold standard" mercuric chloride base. Paired positive fecal specimens (106 from 64 patients) were collected and examined microscopically by the trichrome stain technique. There were 161 instances in which organism trophozoite and/or cyst stages were identified and 3 in which human cells were identified. Morphology, clarity of nuclear and cytoplasmic detail, overall color differences, and the ease or difficulty in detecting intestinal protozoa in fecal debris, as well as the number of patients with a missed diagnosis, were assessed from the permanent stained smear. Overall organism morphology of the intestinal protozoa preserved in zinc sulfate-PVA was not always equal in nuclear and cytoplasmic detail or range of color after permanent staining to that seen with mercuric chloride-PVA. However, the same organisms were usually identified in both specimens, with the exception of situations in which organism numbers were characterized as rare (no organisms per 10 oil immersion fields at x1,000 magnification but at least one organism in the smear) [9 of 161 (5.6%)] or the organism was missed because of poor morphologic detail [12 of 161 (7.5%)]. In only six of these cases [6 of 161 (3.7%)] did the results involve pathogens. The patient diagnosis was missed in four cases of amebiasis and two cases of giardiasis; in both situations the organism numbers were rare. There were no discrepant results with Dientamoeba fragilis. Overall agreement between the two PVA-based results was 87.0% (140 of 161); when the instances of rare organisms were disregarded, the overall agreement was 92.5% (149 of 161). On the basis of these findings, zinc-PVA is viable substitute for mercuric chloride-PVA used for trichrome permanent stained smears.
Serologic analysis of white-tailed deer sera for antibodies to Borrelia burgdorferi by enzyme-linked immunosorbent assay and western immunoblotting
Authors: Gill J S , McLean R G , Neitzel D F , Johnson R C
Published: January 2020

White-tailed deer serum samples were collected in the Minneapolis-St. Paul, Minn., metropolitan area during the fall and winter months from 1989 to 1992 and analyzed for antibodies to Borrelia burgdorferi, the etiologic agent of Lyme borreliosis. Ninety-eight percent of the serum samples were collected from regions where currently the vector tick, Ixodes dammini, is nonexistent. Antibodies to B. burgdorferi were detected in 2.2% of 508 samples by enzyme-linked immunosorbent assay, and their presence was confirmed by Western immunoblot analysis. Western immunoblotting yielded mean numbers of reactive bands of 0.1 and 6.0 for samples that were negative and positive for antibodies by enzyme-linked immunosorbent assay, respectively. The molecular weights of the antigens in many of the reactive bands from positive samples were similar to the molecular weights of antigens reactive with samples from humans with Lyme borreliosis. An antibody response to the major outer surface proteins A and B was not detected. Serologic analysis of deer sera may provide a valuable method for surveillance programs designed to monitor the spread of B. burgdorferi in nature.
An OspA serotyping system for Borrelia burgdorferi based on reactivity with monoclonal antibodies and OspA sequence analysis
Authors: Wilske B , Preac-Mursic V , Göbel U B , Graf B , Jauris S , Soutschek E , Schwab E , Zumstein G
Published: January 2020

A total of 136 Borrelia burgdorferi sensu latu strains from various biological sources (ticks, human skin, and cerebrospinal fluid) and geographical sources (Europe and North America) were investigated by Western blot (immunoblot) with eight monoclonal antibodies against different epitopes of the outer surface protein A (OspA). On the basis of the differential reactivities of these monoclonal antibodies, seven OspA serotypes were defined. As determined by 16S rRNA sequence analysis, these serotypes correlated well with recently delineated genospecies: serotype 1 corresponds to B. burgdorferi sensu strictu, serotype 2 corresponds to group VS461, and serotypes 3 to 7 correspond to Borrelia garinii sp. nov. (G. Baranton, D. Postic, I. Saint Girons, P. Boerlin, J.-C. Piffaretti, M. Assous, and P. A. D. Grimont, Int. J. Syst. Bacteriol. 42:378-383, 1992). Antigenic differences were confirmed by partial sequence analysis of OspA of representatives of each serotype. Comparative sequence analysis suggested that serotype 5 OspA resulted from genetic recombination of serotype 4 and 6 ospA genes. Serotype 2 (group VS461) was most prevalent among European skin isolates (49 of 62 isolates). Among all B. garinii strains included in this study, serotype 6 was most frequently found in ticks and only rarely in human skin and cerebrospinal fluid, whereas serotypes 4 and 5 were isolated from patients but never from ticks. Our data suggest different pathogenic potentials and organotropisms of distinct OspA serotypes and raise the question of true antigenic variation among B. garinii strains.
Serotyping of Cryptococcus neoformans by using a monoclonal antibody specific for capsular polysaccharide
Authors: Dromer F , Gueho E , Ronin O , Dupont B
Published: January 2020

The importance of epidemiological studies of cryptococcosis has increased since the beginning of the AIDS epidemic. Cryptococcus neoformans exists in two varieties defining four serotypes, Cryptococcus neoformans var. neoformans (serotypes A and D) and Cryptococcus neoformans var. gattii (serotypes B and C). The varieties are easy to distinguish by their differences of growth on diagnostic media. We propose here an easy serotyping method combining diagnostic media and a direct immunofluorescence assay with one monoclonal antibody (E1) specific for cryptococcal polysaccharide. The method was validated by the blinded testing of four to five reference strains of each serotype. Immunofluorescence patterns were characteristic of a given serotype provided that the variety of the strain had been defined before. For C. neoformans var. neoformans, a bright, homogeneous staining with several cell aggregates was characteristics of serotype A, whereas only a few serotype D cells were positive. For C. neoformans var. gattii, a completely negative isolate was serotype C, whereas the population of serotype B included a majority of negative cells but also included positive cells with a speckled pattern. The method was then used to serotype 156 clinical isolates from France and isolates from areas where C. neoformans var. gattii was endemic before the AIDS epidemic (13 strains from Rwanda and Zaire and 5 strains from Australia). The specificity of E1 was defined by its reactivity with various Cryptococcus spp. and analyzed according to the described cryptococcal antigenic factors. We conclude from this study that E1 provides a rapid and reliable means to serotype multiple isolates of C. neoformans.
Cultivation of Mycobacterium paratuberculosis from bovine fecal samples by using elements of the Roche MB Check system
Authors: Ridge S E
Published: January 2020

Components of a commercially available, nonradiometric, biphasic (liquid medium then solid medium) system for the detection of Mycobacterial species, Roche MB Check, were adapted for the isolation of Mycobacterium paratuberculosis from bovine fecal specimens. A two-stage culture procedure was developed in which processed fecal samples were incubated in modified commercial liquid medium and then subcultured onto Herrold's egg yolk medium with mycobactin. By using known culture-positive samples and/or samples from animals clinically affected with paratuberculosis, it was found that visible colonial growth on solid media could be obtained after 4 weeks of incubation in liquid medium containing egg yolk and mycobactin followed by 8 weeks of incubation on Herrold's egg yolk medium. In the second part of the study, conventional fecal culture (sample sedimentation in hexadecylcetylpyridinium chloride followed by incubation on Herrold's egg yolk medium) was compared with the two-stage system using a two-step centrifugation technique for sample preparation. One hundred fecal samples from clinically normal but absorbed-enzyme immunoassay-positive cattle were used for the comparison. Conventional culture yielded a sensitivity of 16.5%, whereas the sensitivity of the two-stage system was 29.4%. When used in parallel, the tests detected 36.5% of the samples. There was no significant difference between the two methods in the time taken to obtain visible colonies. These results indicate that the two-stage method is a sensitive method for isolation of M. paratuberculosis from fecal samples obtained from cattle with clinical paratuberculosis. In addition, the two-stage system is more sensitive than conventional culture for the isolation of M. paratuberculosis from subclinically infected cattle.
Comparison of Rambach agar, SM-ID medium, and Hektoen Enteric agar for primary isolation of non-typhi salmonellae from stool samples
Authors: Dusch H , Altwegg M
Published: January 2020

Stool samples (n = 504) were streaked simultaneously onto Rambach agar (R agar; E. Merck, Darmstadt, Germany), SM-ID medium (bioMérieux S.A., Montalieu-Vercieu, France), and Hektoen Enteric (HE) agar (BBL Becton-Dickinson, Baltimore, Md.) in order to evaluate the performances of the first two media in comparison with that of the well-established HE agar. Following overnight cultivation at 37 degrees C, 29 samples (5.8%) were positive for non-typhi salmonellae on at least one of the three media. Sensitivities and specificities were 69 and 98%, 79 and 85%, and 100 and 79% for R, SM-ID, and HE agars, respectively. On the basis of the poor sensitivities, R and SM-ID agars are not recommended as primary plating media when screening for non-typhi salmonellae. However, the high specificity of R agar may help to reduce the work load when this medium is used for plating after enrichment.
Typing of Clostridium difficile by western immunoblotting with 10 different antisera
Authors: Kato H , Cavallaro J J , Kato N , Bartley S L , Killgore G E , Watanabe K , Ueno K
Published: January 2020

Western blotting (immunoblotting) with antisera against each of 10 reference serogroups was evaluated as a means of typing Clostridium difficile. A total of 164 clinical isolates of C. difficile were tested. Variations in band profiles in each serogroup were used to type isolates into subserogroups. This technique was useful for an epidemiological investigation.
Human herpesvirus 6 (HHV-6) variant B accounts for the majority of symptomatic primary HHV-6 infections in a population of U.S. infants
Authors: Dewhurst S , McIntyre K , Schnabel K , Hall C B
Published: January 2020

Two variants of human herpesvirus 6 were identified. To assess their epidemiology and disease association, we analyzed viral isolates and/or uncultured peripheral blood mononuclear cells from 76 infants with symptomatic primary infection. In 97% of cases, human herpesvirus 6 variant B was detected, but variant A was not.
Evaluation of the Vitek EPS enteric pathogen screen card for detecting Salmonella, Shigella, and Yersinia spp
Authors: Imperatrice C A , Nachamkin I
Published: January 2020

We evaluated the Vitek EPS card as a screen for the enteric pathogens Salmonella spp., Shigella spp., and Yersinia enterocolitica. Salmonella spp., Shigella spp., and Y. enterocolitica (125, 54, and 5 isolates, respectively) and 81 nonenteric pathogens that might be selected for screening from primary plates (non-lactose fermenters) were tested. The EPS card correctly identified 183 of 184 pathogens tested (sensitivity, 99.5%). Of 81 nonenteric pathogens screened with the EPS card, 8 were identified as possible enteric pathogens (specificity, 90.1%). We reviewed our stool culture records over the past 1.5 years and analyzed the specificities of TSI-urea screens for 300 stool cultures that had suspicious colonies. From 55 of 300 stool cultures, either Salmonella spp. or Shigella spp. were isolated, and from 245 stool cultures, no pathogen was isolated. Of the 245 negative cultures, 166 gave false-positive screening-test results that resulted in further biochemical identification procedures (Analytab Products or Vitek identification). Thus, the specificity of the TSI-urea screen in our experience was 32.2%. The Vitek EPS card was shown to be a more cost-effective screening procedure than the TSI-urea screen.
Evaluation of the PACE 2 Neisseria gonorrhoeae assay by three public health laboratories
Authors: Hale Y M , Melton M E , Lewis J S , Willis D E
Published: January 2020

The Gen-Probe PACE 2 DNA probe assay for Neisseria gonorrhoeae was compared with conventional culture techniques in three Florida public health laboratories with 436 patients (271 females and 165 males). The prevalence rates based on culture were 19.9, 55.8, and 33.5% for females, for males, and overall, respectively. Twenty-seven probe-positive specimens gave negative culture results. Twenty of these specimens were resolved as true positives after retesting with a probe competition assay. The resolved sensitivity, specificity, positive predictive value, and negative predictive value were 99.4, 99.6, 99.4, and 99.6%, respectively.
Mixed-morphotype broth microdilution susceptibility testing of Pseudomonas aeruginosa from cystic fibrosis patients
Authors: Van Horn K G
Published: January 2020

Multiple morphotypes of Pseudomonas aeruginosa isolated from 50 respiratory specimens of cystic fibrosis patients were tested for correlation of broth microdilution susceptibility results of a mixed-morphotype inoculum with a predicted antibiogram of the individual isolates. The overall correlation was 96.0%, with only 1.6% very major or major errors.
Oxyrase, a method which avoids CO2 in the incubation atmosphere for anaerobic susceptibility testing of antibiotics affected by CO2
Authors: Spangler S K , Appelbaum P C
Published: January 2020

The Oxyrase agar dilution method, with exclusion of CO2 from the environment, was compared with the reference agar dilution method recommended by the National Committee for Clinical Laboratory Standards (anaerobic chamber with 10% CO2) to test the susceptibility of 51 gram-negative and 43 gram-positive anaerobes to azithromycin and erythromycin. With the Oxyrase method, anaerobiosis was achieved by incorporation of the O2-binding enzyme Oxyrase in addition to susceptibility test medium, antibiotic, and enzyme substrates into the upper level of a biplate. Plates were covered with a Brewer lid and incubated in ambient air. With azithromycin, Oxyrase yielded an MIC for 50% of strains tested (MIC50) and MIC90 of 2.0 and 8.0 micrograms/ml, compared to 8.0 and > 32.0 micrograms/ml in standard anaerobic conditions. At a breakpoint of 8.0 micrograms/ml, 90.4% of strains were susceptible to azithromycin with Oxyrase, compared to 53.2% in the chamber. The corresponding erythromycin MIC50 and MIC90 were 1.0 and 8.0 micrograms/ml with Oxyrase, compared to 4.0 and > 32.0 micrograms/ml by the reference method, with 89.3% of strains susceptible at a breakpoint of 4 micrograms/ml with Oxyrase, compared to 60.6% in CO2. Exclusion of CO2 from the anaerobic atmosphere when testing for susceptibility to azalides and macrolides yielded lower MICs, which may lead to a reconsideration of the role played by these compounds in treatment of infections caused by these strains.
Fast DNA isolation from Histoplasma capsulatum: methodology for arbitrary primer polymerase chain reaction-based epidemiological and clinical studies
Authors: Woods J P , Kersulyte D , Goldman W E , Berg D E
Published: January 2020

The arbitrary primer polymerase chain reaction (also called random amplified polymorphic DNA, or RAPD) is a DNA fingerprinting method that provides an efficient, sensitive way of discriminating between independent isolates of Histoplasma capsulatum, but its widespread application has been hampered by the arduous 2-day procedure traditionally used to extract DNA from H. capsulatum. We present here a quick (approximately 2-h) extraction method and show that the resultant DNA is suitable for sensitive and reproducible identification of individual strains of this pathogenic fungus.
Pseudomonas aeruginosa folliculitis acquired through use of a contaminated loofah sponge: an unrecognized potential public health problem
Authors: Bottone E J , Perez A A
Published: January 2020

Pseudomonas aeruginosa folliculitis is a well-known entity that occurs among users of closed-cycle recreational water sources such as whirlpools, swimming pools, and hot tubs. In the absence of this epidemiologic link, isolated cases are difficult to diagnose. We encountered a patient who developed P. aeruginosa folliculitis subsequent to the use of a loofah sponge grossly contaminated with the same P. aeruginosa strain (serotype 10; pyocin type 1/a 4,b) that was recovered from her skin lesions. Furthermore, we demonstrated that sterile unused loofah sponges can serve as the sole growth-promoting substrate for P. aeruginosa. To obviate the potential public health problem of contaminated loofah sponges, it is strongly recommended that manufacturers append, and consumers adhere to, instructions as to the care of loofah sponges, which includes allowing the sponge to dry after use.
Numerical approach to reference identification of Staphylococcus, Stomatococcus, and Micrococcus spp
Authors: Rhoden D L , Hancock G A , Miller J M
Published: January 2020

A numerical-code system for the reference identification of Staphylococcus species, Stomatococcus mucilaginosus, and Micrococcus species was established by using a selected panel of conventional biochemicals. Results from 824 cultures (289 eye isolate cultures, 147 reference strains, and 388 known control strains) were used to generate a list of 354 identification code numbers. Each six-digit code number was based on results from 18 conventional biochemical reactions. Seven milliliters of purple agar base with 1% sterile carbohydrate solution added was poured into 60-mm-diameter agar plates. All biochemical tests were inoculated with 1 drop of a heavy broth suspension, incubated at 35 degrees C, and read daily for 3 days. All reactions were read and interpreted by the method of Kloos et al. (G. A. Hebert, C. G. Crowder, G. A. Hancock, W. R. Jarvis, and C. Thornsberry, J. Clin. Microbiol. 26:1939-1949, 1988; W. E. Kloos and D. W. Lambe, Jr., P. 222-237, in A. Balows, W. J. Hansler, Jr., K. L. Herrmann, H. D. Isenberg, and H. J. Shadomy, ed., Manual of Clinical Microbiology, 5th ed., 1991). This modified reference identification method was 96 to 98% accurate and could have value in reference and public health laboratory settings.
Direct detection of Bacillus anthracis DNA in animals by polymerase chain reaction
Authors: Makino S I , Iinuma-Okada Y , Maruyama T , Ezaki T , Sasakawa C , Yoshikawa M
Published: January 2020

Bacillus anthracis is a soil pathogen capable of causing anthrax. To establish a method for specifically detecting B. anthracis for practical applications, such as for the inspection of slaughterhouses, the cap region, which is essential for encapsulation in B. anthracis, was used in a DNA hybridization study by polymerase chain reaction (PCR). Oligonucleotide primers were designed to amplify a 288-bp DNA fragment within the capA gene by PCR. The amplified DNA sequence specifically hybridized to the DNA of B. anthracis but not to that of other bacterial strains tested. Since this PCR-based method efficiently and specifically detected the capA sequence of bacteria in blood and spleen samples of mice within 8 h after the administration of live B. anthracis, this PCR system could be used for practical applications. By using lysis methods in preparing the samples for PCR, it was possible to amplify the 288-bp DNA segment from samples containing very few bacteria, as few as only 1 sporeforming unit, indicating that the PCR detection method developed in this study will permit the monitoring of B. anthracis contamination in the environment.
Septicemia and meningitis caused by Helicobacter cinaedi in a neonate
Authors: Orlicek S L , Welch D F , Kuhls T L
Published: January 2020

Helicobacter cinaedi has been most frequently isolated from rectal swabs of homosexual men with proctocolitis. The microorganism is a normal intestinal inhabitant of hamsters. We report a case of septicemia and meningitis by H. cinaedi in a neonate whose mother cared for pet hamsters during the first two trimesters of her pregnancy. The isolate was detected after 3 days of incubation in a Bact/Alert pediatric blood culture vial and an enrichment broth culture of the cerebrospinal fluid. H. cinaedi should be added to the list of unusual fastidious organisms that cause sepsis and meningitis in the newborn.
Two highly antigenic sites in the human immunodeficiency virus type 1 reverse transcriptase
Authors: Björling E , Boucher C A , Samuelsson A , Wolfs T F , Utter G , Norrby E , Chiodi F
Published: January 2020

Antibodies to human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) are found in the serum of the majority of infected individuals, and inhibition of RT polymerase activity by HIV-1-positive sera can be demonstrated in vitro. The binding sites of human antibodies on the protein have not yet been identified. We synthesized overlapping peptides covering the entire RT protein of HIV-1 and used them in an enzyme-linked immunosorbent assay system to map the reactivities of HIV-1 and HIV-2 antibody-positive sera. Two highly antigenic regions were identified by both HIV serotypes. One region was found in the central part of the RT protein (amino acids 261 to 280) and another was found at the carboxy terminus in the RNase H portion of RT (amino acids 517 to 536). Comparison of the serological results with the crystal structure of the RT revealed that the antigenic region in the RNase H portion is located at the surface of the protein. The other antibody-binding site (amino acids 261 to 280) was located in the "thumb" region of the polymerase domain of RT. Polyclonal antibodies to either of the antibody-binding sites do not affect the polymerase activity of the RT protein.
Detection of Aspergillus fumigatus by polymerase chain reaction
Authors: Spreadbury C , Holden D , Aufauvre-Brown A , Bainbridge B , Cohen J
Published: January 2020

Aspergillus fumigatus is an opportunistic nosocomial pathogen causing an often fatal pneumonia, invasive aspergillosis (IA), in immunosuppressed patients. Oligonucleotide primers were used to amplify a 401-bp fragment spanning the 26S/intergenic spacer region of the rDNA complex of A. fumigatus by the polymerase chain reaction (PCR). The primers were highly sensitive and specific: as little as 1 pg of A. fumigatus genomic DNA could be detected, and the primers only amplified DNA from A. fumigatus and not any other fungal, bacterial, viral, or human DNA tested. Using the PCR, we were able to detect A. fumigatus DNA in lung homogenates from immunosuppressed mice experimentally infected with A. fumigatus but not from immunosuppressed uninfected controls. There was 93% correlation between the culture results and the PCR results. In a retrospective clinical study, the sensitivity of the PCR for the detection of A. fumigatus in clinical samples was confirmed by positive amplification in three of three culture-positive respiratory samples from confirmed cases of IA. Because isolation of Aspergillus spp. may reflect contamination and colonization without infection, the feasibility of using the PCR was evaluated by analyzing culture-negative samples from both immunosuppressed patients at high risk for IA and immunocompetent patients with other lung infections. Only 2 of 10 patients were culture negative and PCR positive in the high-risk group, and 2 of 7 patients were culture negative and PCR positive in the immunocompetent group. The results indicate that PCR detection might be a valuable adjunct to current laboratory methods to diagnose IA.
Serologic analysis of human rotavirus serotypes P1A and P2 by using monoclonal antibodies
Authors: Padilla-Noriega L , Werner-Eckert R , Mackow E R , Gorziglia M , Larralde G , Taniguchi K , Greenberg H B
Published: January 2020

Three human rotavirus (HRV) VP4 serotypes and one subtype have been described on the basis of a fourfold or an eightfold-or-greater difference in neutralization titer when tested with hyperimmune antisera to recombinant VP4 or VP8* (serotypes P1A, P1B, P2, and P3). To start to analyze the antigenic basis underlying serotype specificity, we produced a library of 13 VP4-specific neutralizing monoclonal antibodies (NMAbs) to two HRVs, the serotype P1A strain Wa and the serotype P2 strain ST3, and characterized the reactivity of these NMAbs with a panel of serotypically diverse HRV strains by neutralization assay and enzyme-linked immunosorbent assay (ELISA). We characterized the serotypic specificity of the NMAbs by using a fourfold or an eightfold-or-greater difference in titer against the homologous (i.e., immunogen) and heterologous strains as a criterion for serotype. Some ST3-derived NMAbs reacted specifically with serotype P2 HRVs by ELISA and/or neutralization assay, while some Wa-derived NMAbs reacted specifically by ELISA and/or neutralization assay with some or all serotype P1A HRVs. Other Wa- and ST3-derived NMAbs reacted with some or all serotype P1A and P2 HRV strains by neutralization assay and ELISA. Most NMAbs did not react with serotype P1B or P3 strains. In previous studies, three distinct operationally defined epitopes have been identified on VP4 by examining the reactivity patterns of selected antigenic variants of HRV strain KU. At least one of the NMAbs described here recognizes an epitope unrelated to these previously identified epitopes, since it neutralized both KU and its variants.
Elimination of contaminating DNA within polymerase chain reaction reagents: implications for a general approach to detection of uncultured pathogens
Authors: Meier A , Persing D H , Finken M , Böttger E C
Published: January 2020

Analysis based on comparisons of 16S rRNA sequences provides a rapid and reliable approach to identifying human pathogens. By directing oligonucleotide primers at sequences conserved throughout the eubacterial kingdom, bacterial 16S ribosomal DNA sequences of virtually any member of the eubacterial kingdom can be amplified by polymerase chain reaction and subsequently analyzed by sequence determination. Indeed, automated systems for broad-range amplification, sequencing, and data analysis are now feasible and may form the basis of the next generation of automated microbial identification systems. However, identification of pathogens by this strategy is hampered by the frequent contamination of reagents used for the amplification reaction, in particular Taq polymerase, with exogenous bacterial DNA. Here, we describe detailed investigations on the use of 8-methoxypsoralen and long-wave UV light to eliminate contaminating DNA in polymerase chain reaction reagents. The clinical utility of the developed procedure was demonstrated in a case of paucibacillary osteomyelitis, for which no specific bacterial agent had been cultured.
Simple colorimetric microtiter plate hybridization assay for detection of amplified Mycobacterium leprae DNA
Authors: van der Vliet G M , Hermans C J , Klatser P R
Published: January 2020

The detection of amplified products resulting from polymerase chain reactions (PCRs) remains a complicated process. To simplify the detection procedures, we developed a colorimetric microtiter plate hybridization assay for the specific detection of 5'-biotinylated PCR fragments of Mycobacterium leprae DNA. For this assay, an M. leprae DNA capture probe was made and immobilized on the wells of a microtiter plate. Hybridization of the biotin-labeled PCR fragments was detected through enzymatic color development. The resulting optical densities showed a logarithm-linear relationship with the amount of template DNA and corresponded to the intensity of the bands obtained through gel analysis and Southern blotting of the PCR products. The sensitivity of the assay was found to be 125 fg of genomic M. leprae DNA, or 20 lysed bacilli, revealing a detection limit similar to that of agarose gel analysis. The efficient coamplification of human DNA was used as a positive control for the presence of inhibitory substances in clinical material. For detection of human PCR products, a human DNA capture probe was also constructed for the colorimetric assay. This dual setup for hybridization, which thus detected both M. leprae and human DNA PCR products, was useful for ascertaining the presence of inhibiting substances in clinical specimens. All biopsy specimens (n = 10) from untreated patients with leprosy were positive. Apparently, this assay is more sensitive than microscopy, because biopsy specimens from half of the patients were negative upon histopathological examination. Biopsy specimens from three treated patients were negative, as were those from the three patients who did not have leprosy. We conclude that this colorimetric assay can replace agarose gel analysis and Southern hybridization, because it is as sensitive as those methods. Its advantages over conventional gel analysis and Southern hybridization are that it is less cumbersome and more rapid.
Comparison of different methods and cell lines for isolating measles virus
Authors: Forthal D N , Blanding J , Aarnaes S , Peterson E M , de la Maza L M , Tilles J G
Published: January 2020

Infectivity titers were determined for seven strains of measles virus by using various methods and cell lines. The use of B95-8 cells in a shell vial assay resulted in the highest infectivity titers. Our data suggest that B95-8 is the cell line of choice for the isolation of measles virus.
Dot immunobinding assay for simultaneous detection of specific immunoglobulin G antibodies to measles virus, mumps virus, and rubella virus
Authors: Condorelli F , Ziegler T
Published: January 2020

A dot immunobinding assay was used to detect antibodies to measles virus, mumps virus, and rubella virus antigens. Filter paper soaked with serum or whole blood was directly applied to the antigen-coated nitrocellulose sheets. The test was easy to perform, and its results agreed very well with those obtained by standard enzyme immunoassay.
Prevalence of antibodies to Coxiella burnetii in Japan
Authors: Htwe K K , Yoshida T , Hayashi S , Miyake T , Amano K , Morita C , Yamaguchi T , Fukushi H , Hirai K
Published: January 2020

We evaluated the prevalence of Coxiella burnetii antibodies in 626 human serum samples (275 from veterinarians, 107 from meat-processing workers, 184 from respiratory-disorder patients, and 60 from healthy humans) by the indirect immunofluorescence test. Of the serum samples examined, 54 (8.6%) and 103 (16.5%) reacted positively to phase I and II antigens, respectively, of C. burnetii. The rates differed for healthy humans and respiratory-disorder patients. Antibody prevalence was high for healthy humans living in close contact with animals (e.g., veterinarians and meat-processing workers).
Epidemiological typing of Moraxella catarrhalis by using DNA probes
Authors: Beaulieu D , Scriver S , Bergeron M G , Low D E , Parr T R , Patterson J E , Matlow A , Roy P H
Published: January 2020

Small-fragment restriction enzyme analysis and DNA-DNA hybridization were used to compare 60 strains of Moraxella catarrhalis isolated from various geographic locations. Restriction enzyme analysis with HaeIII resulted in 46 different patterns, 7 of which were shared by more than one isolate. Hybridizations with two DNA probes resulted in 18 different patterns, 11 of which were shared by more than one isolate. Strains with the same restriction enzyme pattern always had the same hybridization pattern. However, of the 50 strains that shared the 11 hybridization patterns, 39 could be further differentiated by restriction enzyme analysis. We found that hybridization is a method that is specific for the epidemiological typing of M. catarrhalis, but because of limited sensitivity, combination with small-fragment restriction enzyme analysis may be necessary to better determine the relatedness of strains.
Biotypes and serotypes of Haemophilus influenzae from patients with meningitis in the city of São Paulo, Brazil
Authors: Landgraf I M , Vieira M F
Published: January 2020

A total of 1,094 Haemophilus influenzae isolates from cerebrospinal fluid were examined by biochemical and serological means. Most of them belonged to biotype I (70.9%) and to serotype b (99.4%). The relationship of biotypes I and II to the ages of the patients was shown to be significant (P < 0.001).
Evaluation of the API Coryne system for identification of Listeria species
Authors: Kerr K G , Hawkey P M , Lacey R W
Published: January 2020

The API Coryne system, a commercially available system for the identification of coryneform bacteria, was used to identify 103 strains of Listeria spp. from clinical and environmental sources. All isolates were identified correctly to the genus or species level, although complete characterization also required tests for beta-hemolysis and CAMP reaction.
Rapid and specific identification of Yersinia pestis by using a nested polymerase chain reaction procedure
Authors: Campbell J , Lowe J , Walz S , Ezzell J
Published: January 2020

We developed a 4-h nested polymerase chain reaction assay that detected a region of the plasminogen activator gene of Yersinia pestis in 100% of 43 Y. pestis strains isolated from humans, rats, and fleas yet was unreactive with the closely related species Yersinia enterocolitica and Yersinia pseudotuberculosis.
Isolation of a Citrobacter freundii strain which carries the Escherichia coli O157 antigen
Authors: Bettelheim K A , Evangelidis H , Pearce J L , Sowers E , Strockbine N A
Published: January 2020

A biochemically typical strain of Citrobacter freundii which carries the Escherichia coli O157 antigen is described. The significance of differentiating such strains from typical E. coli O157 strains is stressed.
Rapid and highly reproducible method for antifungal susceptibility testing of Aspergillus species
Authors: Yamada H , Kohno S , Maesaki S , Koga H , Kaku M , Hara K , Tanaka H
Published: January 2020

A new method for determining the MICs for Aspergillus species with slant-shaking incubation is described. The method was rapid (24 h), produced sharp visual end points, and showed high reproducibility. Additionally, MICs measured by this method correlated well with, as well as were two- to sixfold lower than, those by a reference method.