bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of restriction endonuclease fingerprinting of chromosomal DNA and plasmid profile analysis for characterization of multiresistant coagulase-negative staphylococci in bacteremic neonates
Authors: Bialkowska-Hobrzanska H , Jaskot D , Hammerberg O
Published: January 2020

A procedure was developed for restriction endonuclease fingerprinting (REF) of the chromosomal DNA of coagulase-negative staphylococci. A total of 48 isolates comprising 29 Staphylococcus epidermidis and 19 Staphylococcus haemolyticus isolates from blood and mucocutaneous sites of 15 premature neonates were characterized by REF, plasmid profile (PP) analysis, antimicrobial susceptibility testing, biotyping, and slime production. On the basis of REF analysis of chromosomal DNA, the 48 coagulase-negative staphylococcal isolates were subdivided into 10 subgroups, whereas PP analysis subdivided the strains into 20 distinct subgroups. REF analysis of total DNA (i.e., chromosome plus plasmid) resulted in the same 20 subgroups as were subdivided by PP analysis. The high discriminatory power of PP analysis was associated with the variability of plasmid content in coagulase-negative staphylococcal strains isolated during the outbreak. REF patterns were found to be stable both in vitro and in vivo. Isolates carried from 2 to 10 plasmids that ranged in molecular size from 0.9 to 39.5 megadaltons. Plasmids were disseminated among the coagulase-negative staphylococci, regardless of the genetic relatedness of their chromosomal DNAs. Hence, a lack of correlation existed between the grouping of isolates by REF analysis of chromosomal DNA and the grouping by PP analysis. There were one and two distinct chromosomal patterns among 4 of 4 blood cultures and 15 of 15 mucocutaneous cultures of S. haemolyticus, respectively. In contrast, a higher proportion of distinct chromosomal patterns was found for S. epidermidis in blood cultures (7 of 11 cultures) compared with those identified for isolates in mucocutaneous cultures (6 of 18 cultures). In summary, REF analysis of chromosomal DNA, rather than total DNA, is a useful marker for epidemiological investigations of coagulase-negative staphylococci. PP analysis can also be used to provide additional epidemiological information regarding the most recent genetic events.
Polymerase chain reaction amplification and typing of rotavirus nucleic acid from stool specimens
Authors: Gouvea V , Glass R I , Woods P , Taniguchi K , Clark H F , Forrester B , Fang Z Y
Published: January 2020

The rotavirus gene segment coding for the major outer capsid glycoprotein vp7 was amplified directly from stool specimens by the polymerase chain reaction (PCR). Double-stranded RNA extracted from stool samples was used as the template for reverse transcription, which was followed immediately and in the same reaction mix with amplification, using the Taq polymerase. Various conditions were examined to optimize the yield of the amplified gene. The concentrations of MgCl2, dimethyl sulfoxide, and template RNA were critical. The choice of primer pairs allowed amplification of the entire segment or specific portions. By using type-specific primers derived from distinct regions on the gene, we devised a PCR typing method in which each human serotype virus produced a characteristic segment size, readily identifiable in agarose gels. The PCR typing method was applied to 10 rotavirus reference strains, including all 6 known human serotypes (serotypes 1, 2, 3, 4, 8, and 9), and to 34 stool specimens previously serotyped by an enzyme immunoassay with monoclonal antibodies. An absolute correlation was found between the molecular and serologic methods. In addition, 14 stool specimens nonserotypable by an enzyme immunoassay with monoclonal antibodies could be typed by the PCR method. Besides the application for rotavirus detection and typing directly from stools, the PCR method provides a rapid and efficient means of obtaining large quantities of cDNA suitable for sequencing, cloning, and other genetic studies, precluding the need for cell culture and virus purification.
Performance and cost-effectiveness of a dual rapid assay system for screening and confirmation of human immunodeficiency virus type 1 seropositivity
Authors: Spielberg F A , Kabeya C M , Quinn T C , Ryder R W , Kifuani N K , Harris J , Bender T R , Heyward W L , Tam M R , Auditore-Hargreaves K
Published: January 2020

Recent studies have shown that rapid, instrument-free assays for the detection of antibody to human immunodeficiency virus (HIV) can be as sensitive and specific as enzyme-linked immunosorbent assay (ELISA) for screening of donated blood in developing countries. Currently, however, specimens which test positive on a screening assay must still be confirmed by Western blot (immunoblot), a method which is not feasible in most developing-country laboratories. We examined whether a testing hierarchy which utilizes neither conventional ELISA nor Western blot can be reliably used for screening and confirmation of HIV infection in a high-risk population. In a retrospective analysis of 3,878 specimens which were screened for antibody to HIV in Kinshasa, Zaire, we observed that a testing hierarchy consisting of duplicate HIVCHEK screening assays followed by duplicate Serodia-HIV confirmatory assays resulted in correct confirmation of all ELISA- and Western blot-positive specimens. We conclude that such a testing hierarchy can produce highly accurate results for identification of positive specimens in routine HIV testing and provides a practical alternative to conventional methods of HIV screening and confirmation.
Specific detection of enteroviruses in clinical samples by molecular hybridization using poliovirus subgenomic riboprobes
Authors: Petitjean J , Quibriac M , Freymuth F , Fuchs F , Laconche N , Aymard M , Kopecka H
Published: January 2020

Enteroviruses were specifically detected in crude clinical specimens or in cell cultures in which the viruses were amplified by dot hybridization by using poliovirus type 1-derived, subgenomic radiolabeled cRNA probes (riboprobes). The sensitivity of this test varied from 2.5 to 33%, when clinical specimens without cell culture were examined, and was about 85% in cell culture lysates. The specificity of the test was 90 to 100%. The riboprobe corresponding to the 5'-noncoding sequence specifically detected the majority of enteroviruses (56 of 57 tested); the riboprobe derived from the VPI capsid region hybridized with the three poliovirus serotypes and with some coxsackieviruses type A and with echovirus type 7. Echovirus 22 did not hybridize with any riboprobe. In stool specimens, nasal aspirates, and cerebrospinal fluids from patients with meningitis, only one type of virus was identified in different clinical samples from the same patient by the seroneutralization test. Hybridization allowed the detection of enteroviral RNAs easily in stool specimens and nasal aspirates but with a low efficiency in cerebrospinal fluids without amplification of the viruses in cell cultures.
Detection of serotype-specific antibodies or capsular antigen of Actinobacillus pleuropneumoniae by a double-label radioimmunoassay
Authors: Inzana T J , Clark G F , Todd J
Published: January 2020

Diagnostic tests for Actinobacillus pleuropneumoniae have been problematic because current tests do not use a purified antigen and in most cases measure either antibody or antigen, but not both. We describe a Farr-type double-label radioimmunoassay that utilizes purified, serotype-specific, 3H-capsule to measure antibody to capsule directly or that can measure capsule in a sample indirectly by inhibition of antibody binding. The assay could detect about 1 ng of serotype-specific antibody in serum or at least 100 pg of capsule in a sample. Due to the sensitivity of the assay, false-positive results were common with neat sera (probably due to cross-reacting antibodies to unrelated antigens), but the specificity was improved when the sera were diluted 1:100. The radioimmunoassay should prove to be a useful reference method for research and diagnostic testing and for comparison of new assays for detection of capsule or antibodies to capsule.
Direct detection of group B streptococci from vaginal specimens compared with quantitative culture
Authors: Kontnick C M , Edberg S C
Published: January 2020

Determination of prenatal vaginal carriage of group B streptococci (GBS) is important in the management of newborns. A pronase extraction-latex particle agglutination method (Streptex; Wellcome Diagnostics, Dartford, England) was used to rapidly detect GBS species-specific antigen directly from vaginal specimens. It was compared with quantitative and broth enrichment cultures. A total of 434 vaginal swab specimens were obtained before delivery. GBS cultures were positive for 14.7% of the specimens (64 of 434). Colony counts ranged from 2 to greater than 10(6) CFU per swab. The sensitivities of the direct antigen analysis were 19% (12 of 64) for all cultures and 63% (12 of 19) for specimens heavily colonized with GBS (greater than 10(4) CFU per swab). The specificity of the antigen test was 99.7%, with only one false-positive. There were three false-negative tests with colony counts of greater than 10(6) CFU per swab. The predictive values were 92% for a positive antigen test and 88% for a negative antigen test. The direct immunochemical detection of GBS antigen can be useful in a population of heavily colonized women. Direct latex particle agglutination does not appear to be salutary for a lightly colonized population and does not appear to be able to replace either culture or antigen detection after growth amplification at this time.
Pathogenicity factors and virulence for rainbow trout (Salmo gairdneri) of motile Aeromonas spp. isolated from a river
Authors: Paniagua C , Rivero O , Anguita J , Naharro G
Published: January 2020

Ninety-seven motile Aeromonas strains were isolated over a period of a year from samples of water and sediment collected at different sites along a river. Strains were regularly recovered from all samples, regardless of the source of isolation or seasonal conditions. Isolates were biochemically characterized by the API 20NE system (Analytab Products, Plainview, N.Y.) and classified as Aeromonas hydrophila (74 strains), Aeromonas sobria (11 strains), and Aeromonas caviae (12 strains). Despite the high level of homogeneity observed in their biochemical patterns, they displayed different degrees of virulence for fish; 72.02% of A. hydrophila isolates and 63% of A. sobria isolates were virulent for fish by intramuscular challenge, but lower frequencies of virulence were observed when intraperitoneal injections were used. All A. caviae strains proved to be avirulent. Caseinases, hemolysins, and Vero cytotoxins were produced by 100, 91, and 94.59%, respectively, of A. hydrophila strains and with lower frequencies and lower caseinase activities by A. sobria isolates. No correlation was found between these activities and the degree of virulence of the strains for fish. Most hydrophobic strains seem to be concentrated in A. caviae, A. sobria, and avirulent A. hydrophila groups. Known virulence markers commonly associated with virulent strains (acriflavine negative and self-pelleting negative and precipitation after boiling positive phenotypes) had a low representation in the total of strains studied and were not associated with virulence.
Effects of bovine serum albumin on the ability of Barbour-Stoenner-Kelly medium to detect Borrelia burgdorferi
Authors: Callister S M , Case K L , Agger W A , Schell R F , Johnson R C , Ellingson J L
Published: January 2020

The ability of decreasing inocula of Borrelia burgdorferi to grow in otherwise identical Barbour-Stoenner-Kelly (BSK) media containing different lots of bovine serum albumin (fraction V) was determined. These media differed significantly in ability to detect B. burgdorferi. Some BSK media required inocula of 2 x 10(5) organisms per ml for detection, while other media could stimulate growth after inoculation with less than 2 organisms per ml. In addition, organisms from the less sensitive BSK media were thinner, longer, and less tightly coiled. The endpoint dilutions of indirect fluorescent-antibody titers, especially immunoglobulin M, exhibited up to 16-fold decreases, and both immunoglobulin G and M titers were more difficult to interpret with diagnostic slides prepared from some longer, thinner B. burgdorferi. These results demonstrate that, when performing laboratory investigations which rely on B. burgdorferi, it is essential that the quality of the BSK medium be determined.
Routine in vitro cultivation of Giardia lamblia by using the string test
Authors: Korman S H , Hais E , Spira D T
Published: January 2020

In vitro axenic cultures of Giardia lamblia were successfully established in 14 successive subjects by a method employing the string test (Entero-Test) for obtaining samples of fluid from the proximal small intestine. This method is applicable to isolating G. lamblia from unselected subjects, including asymptomatic carriers, children, and individuals in diverse or remote geographic regions.
Enzyme-linked immunosorbent assay for distinguishing serological responses of lepromatous and tuberculoid leprosies to the 29/33-kilodalton doublet and 64-kilodalton antigens of Mycobacterium tuberculosis
Authors: Das P K , Rambukkana A , Baas J G , Groothuis D G , Halperin M
Published: January 2020

Immunoblot assays for the antibodies to Mycobacterium tuberculosis sonic extracts showed that all serum specimens of 40 lepromatous and of 28 tuberculoid leprosy patients reacted in a significant manner to 29/33-kilodalton (kDa) doublet and 64-kDa antigens, respectively. By using an enzyme-linked immunosorbent assay, we observed a significantly high immunoglobulin G antibody titer to the purified M. tuberculosis 29/33-kDa doublet and 64-kDa antigens in lepromatous and tuberculoid leprosy patients, respectively, as compared with normal subjects and tuberculosis patients. This enzyme-linked immunosorbent assay serology may be useful for distinguishing two polar types of leprosy and for diagnosing leprosy in general.
Detection by enzyme-linked immunosorbent assay of Aujeszky's disease virus in tissues of infected pigs
Authors: Qvist P , Meyling A , Hoff-Jørgensen R
Published: January 2020

An enzyme-linked immunosorbent assay was developed for the detection of Aujeszky's disease virus antigen in tissue extracts and in nasal swabs. The enzyme-linked immunosorbent assay is based on two different monoclonal antibodies with specificity for the gII glycoprotein of Aujeszky's disease virus. Viral antigen was detected in 81 of 93 tissue extracts prepared from virus-infected organs. Fifteen outbreaks of Aujeszky's disease were analyzed in this study, and they were all identified by the gII antigen enzyme-linked immunosorbent assay.
Reevaluation of the cellular fatty acid composition of Legionella micdadei Bari 2/158
Authors: Moss C W , Lambert-Fair M A
Published: January 2020

The cellular fatty acid composition of Legionella micdadei Bari 2/158 was reevaluated because of its purported differences from other L. micdadei strains and its similarity to L. bozemanii. We found the fatty acid content of this strain to be consistent with that of 11 other strains of L. micdadei, including the presence of an anteiso branched-chain, monounsaturated, 17-carbon acid (Ca17:1) which is characteristic of this species. The double-bond position of Ca17:1 was established at the omega 7 (or delta 9) position by combined gas chromatographic-mass spectrometric analysis of dimethyl disulfide derivatives. The Ca17:1 omega 7 acid was absent in each of 14 strains of L. bozemanii.
Isoprenoid quinones of Campylobacter cryaerophila, C. cinaedi, C. fennelliae, C. hyointestinalis, C. pylori, and "C. upsaliensis"
Authors: Moss C W , Lambert-Fair M A , Nicholson M A , Guerrant G O
Published: January 2020

The isoprenoid quinone contents of Campylobacter cryaerophila, C. cinaedi, C. fennelliae, C. hyointestinalis, C. pylori, and "C. upsaliensis" were determined by reverse-phase thin-layer and high-performance liquid chromatography. All six of these recently named Campylobacter species contained menaquinone-6 (MK-6), but only C. hyointestinalis and "C. upsaliensis" contained 2,[5 or 8]-dimethyl-3-farnesyl-farnesyl-1,4-naphthoquinone (*MK-6), a previously described novel menaquinone of the Campylobacter genus. C. cryaerophila, C. cinaedi, C. fennelliae, and C. pylori contained an unidentified quinone (Un-MK-6) with a molecular weight of 580 and a base peak ion of m/e = 225 by mass spectrometry but with chromatographic properties different from those of MK-6. *MK-6 and Un-MK-6 are important chemotaxonomic markers of Campylobacter and Campylobacter-like organisms.
Ocular infection caused by Psychrobacter immobilis acquired in the hospital
Authors: Gini G A
Published: January 2020

The name Psychrobacter immobilis recently has been proposed for a group of chiefly psychrotrophic, aerobic, gram-negative, nonmotile, oxidase-positive coccobacilli commonly found associated with fish, processed meat, and poultry products. This article reports an ocular infection in a 12-day-old newborn who acquired the infection in the hospital, probably because of frequent manipulations in a closed aerated incubator. Also, this report intends to alert microbiologists to opportunistic infections that might be confused with infections caused by unusual oxidase-positive, gram-negative diplococci and to the isolation of P. immobilis from a human infection.
Identification of coagulase-negative staphylococci by electrophoretic profile of total proteins and analysis of penicillin-binding proteins
Authors: Pierre J , Gutmann L , Bornet M , Bergogne-Berezin E , Williamson R
Published: January 2020

Analyses of total solubilized proteins and penicillin-binding proteins by sodium dodecyl sulfate-polyacrylamide gel electrophoresis were demonstrated to be accurate methods for the identification of coagulase-negative staphylococci. However, penicillin-binding protein profiles were found to be much clearer for the identification of these organisms to species level than was examination of the total solubilized proteins. By using the former technique, 13 reference strains were found to have species-specific penicillin-binding protein profiles, and 150 of 160 randomly collected clinical isolates were identified as belonging to eight of these species. A group of three clinical strains probably represents the recently described species Staphylococcus lugdunensis; the other seven clinical isolates belonging to five species remained unclassified.
Demonstration of heterogeneity among the antigenic proteins of Mobiluncus species
Authors: Schwebke J R , Hillier S L , Fohn M J , Lukehart S A
Published: January 2020

The protein and antigenic profiles of the American Type Culture Collection type strains of Mobiluncus species and those of 114 clinical isolates were determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis and immunoblotting with homologous polyvalent antisera. The majority of isolates (82%) possessed characteristic protein profiles and could be identified to the species level by sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis. The major protein bands were also antigenic, and some antigenic cross-reactivity was noted between the two Mobiluncus species. All of the isolates were examined for reactivity with a panel of 12 monoclonal antibodies previously prepared against the type strains. While 56 of 60 clinical isolates of Mobiluncus curtisii (93%) reacted with one or more of the monoclonal antibodies, only 23 of 54 clinical isolates which were identified as Mobiluncus mulieris by biochemical methods (48%) reacted with one or more of the monoclonal antibodies. One of the 4 M. curtisii isolates (25%) and 11 of the 31 M. mulieris isolates (35%) which did not react with the monoclonal antibodies also had atypical protein profiles. These results demonstrate a high degree of heterogeneity in the protein and antigenic profiles of Mobiluncus isolates and suggest that further taxonomic division may be appropriate.
Expression in Escherichia coli of a dominant immunogen of Trypanosoma cruzi recognized by human chagasic sera
Authors: Cotrim P C , Paranhos G S , Mortara R A , Wanderley J , Rassi A , Camargo M E , da Silveira J F
Published: January 2020

A genomic clone expressing a Trypanosoma cruzi antigen in Escherichia coli was identified using human chagasic sera. Chagasic antibodies affinity purified on extracts of this clone recognized a high-molecular-weight protein expressed in all developmental stages of the parasite life cycle, as well as in various T. cruzi strains. The antigen is associated with the cytoskeleton of the parasite and localizes along the attachment region between the flagellum and the cell body. Antibodies to the recombinant antigen were detected in the sera of 115 chagasic patients from different endemic regions, but not in sera of patients with leishmaniasis, T. rangeli infection, or other parasitic diseases. Our data suggest that the presence of antibodies to this antigen may be specifically associated with Chagas' disease.
Cross-reactions between Actinobacillus (Haemophilus) pleuropneumoniae strains of serotypes 1 and 9
Authors: Mittal K R
Published: January 2020

Actinobacillus pleuropneumoniae strains of serotypes 1 and 9 were studied for their serological properties by means of agglutination, coagglutination (CoA), indirect hemagglutination (IHA), Co-IHA, ring precipitation (RP), and immunodiffusion (ID) tests. Particulate and soluble antigens of unheated and heat-treated bacterial cells were used in various serological tests. Agglutination, CoA, and RP tests demonstrated common antigens between strains of serotypes 1 and 9. Quantitative estimation of serotype-specific antigenic activity by CoA, RP, and ID tests proved useful in differentiating strains of serotypes 1 and 9. IHA and Co-IHA tests using sheep erythrocytes sensitized with unheated or heat-treated whole-cell saline extract and the ID test using boiled whole-cell saline extract as antigen distinguished the strains of serotypes 1 and 9. In studies of absorption of rabbit antisera with heterologous whole-cell antigens there was no absorption of antibodies in tube agglutination and IHA tests, suggesting that serotype 1 and 9 strains belong to two distinct serogroups. It appears that the cross-reactivity between serotype 1 and 9 strains could be due to common epitopes associated with cell wall antigens.
Chemotaxonomic differentiation of legionellae by detection and characterization of aminodideoxyhexoses and other unique sugars using gas chromatography-mass spectrometry
Authors: Fox A , Rogers J C , Fox K F , Schnitzer G , Morgan S L , Brown A , Aono R
Published: January 2020

Legionellae have been differentiated previously by analyzing their carbohydrate contents by gas chromatography with flame ionization detection. In the present study, total ion mode gas chromatography-mass spectrometry (GC-MS) was used to detect a number of unusual sugars, including one that is structurally related to O-methyldideoxyheptoses. Increased sensitivity and selectivity for carbohydrate detection was achieved by selected ion-monitoring GC-MS. Two of the uncommon sugars previously discovered in the legionellae (X1 and X2) were identified as quinovosamine and fucosamine, respectively. Legionella pneumophila contained rhamnose and quinovosamine but not the quinovosamine isomer fucosamine. Tatlockia micdadei and Legionella maceachernii contained large amounts of rhamnose, fucose, and fucosamine but not quinovosamine. These two species were the only legionellae studied that contained another unusual sugar that is referred to as X3, pending determination of its structure. Fluoribacter dumoffi, Fluoribacter bozemanae, and Legionella anisa were varied in their carbohydrate contents, both within and between species, but could be distinguished from L. pneumophila and the T. micdadei and L. maceachernii group. Fluoribacter gormanii was unique among the legionellae in that it lacked both quinovosamine and fucosamine. Legionella jordanis contained other unusual carbohydrates in addition to quinovosamine. GC-MS may have wide application in the differentiation of bacterial species.
Fluorogenic assay for differentiating Staphylococcus warneri and Staphylococcus hominis strains of bovine origin
Authors: White D G , Harmon R J , Langlois B E
Published: January 2020

A fluorogenic assay for the detection of beta-glucosidase was developed as part of a simplified conventional method to distinguish Staphylococcus warneri and Staphylococcus hominis isolated from bovine body sites. The assay is based on the fact that strains of S. warneri produce beta-glucosidase, while strains of S. hominis do not.
Interpretive criteria for disk diffusion susceptibility testing of mupirocin, a topical antibiotic
Authors: Fuchs P C , Jones R N , Barry A L
Published: January 2020

Five hundred gram-positive clinical bacterial isolates were tested for susceptibility to mupirocin by broth microdilution and disk diffusion methods (5- and 10-micrograms disks). All but 1 of 330 staphylococci (including 100 oxacillin-resistant Staphylococcus aureus) were susceptible to less than or equal to 1.0 micrograms of mupirocin per ml. With a susceptible MIC breakpoint of less than or equal to 2.0 micrograms/ml, the corresponding zone diameter breakpoints were greater than or equal to 14 mm for 5-micrograms disks and greater than or equal to 16 mm for 10-micrograms disks. With either disk potency, susceptible staphylococci were effectively separated from more resistant gram-positive species such as the enterococci and gram-positive bacilli.
Rapid, colorimetric identification of Candida albicans
Authors: Perry J L , Miller G R , Carr D L
Published: January 2020

A total of 706 yeast isolates were evaluated in parallel by the Candida albicans Screen (CAS; Carr-Scarborough Microbiologicals, Inc., Stone Mountain, Ga.) test and the germ tube (GT) test in comparison with the API 20C Yeast Identification System. The CAS and GT tests correctly identified 419 of the 422 isolates of C. albicans (99.3%). Two of the false-negative reactions occurring with the CAS were with GT-negative strains of C. albicans. There were two false-positive CAS reactions involving a single strain each of C. parapsilosis and C. tropicalis. Sensitivity and specificity for both tests exceeded 99%, with positive and negative predictive values of 99 and 98%, respectively.
Increased recovery of Legionella micdadei and Legionella bozemanii on buffered charcoal yeast extract agar supplemented with albumin
Authors: Morrill W E , Barbaree J M , Fields B S , Sanden G N , Martin W T
Published: January 2020

The recovery of Legionella micdadei and L. bozemanii serogroups 1 and 2 from infected guinea pig spleens was evaluated by using two culture media: buffered charcoal yeast extract agar with 0.1% alpha-ketoglutarate (BCYE alpha) and the same medium supplemented with 1% bovine serum albumin (ABCYE alpha). At the lowest dilution of spleen tissue (10(-1)), recovery of all strains of L. micdadei and L. bozemanii was more efficient on ABCYE alpha than on BCYE alpha. L. micdadei strains had higher recovery rates on ABCYE alpha after another 10-fold dilution, but recoveries of L. bozemanii were similar on both media. Recovery rates for most test strains were comparable on BCYE alpha and ABCYE alpha at the highest dilution (10(-3)) of tissue tested. The presence of albumin in BCYE alpha increased the recovery rate of L. micdadei more than that of L. bozemanii. The use of ABCYE alpha medium in place of BCYE alpha may improve the recovery of L. micdadei and L. bozemanii from clinical specimens. Preliminary studies indicate that this medium also enhances recovery of certain Legionella spp. from environmental samples.
Two confirmatory tests for identification of Neisseria gonorrhoeae from primary culture
Authors: Ridderhof J C , Vaughan M , Tinney A , Meier F A , Dalton H P
Published: January 2020

We compared a fluorescent monoclonal antibody and a DNA probe for identification of Neisseria gonorrhoeae (GC) from primary genital cultures of presumptive GC and selected bacterial isolates other than GC. The monoclonal antibody was sensitive (94%) and specific (100%) enough to identify GC in selective primary genital culture. The DNA probe was sensitive (95%) but not adequately specific (65%) to function as a confirmatory test.
Two cases of Mycobacterium haemophilum infection in Canada
Authors: Thibert L , Lebel F , Martineau B
Published: January 2020

In 1987, Mycobacterium haemophilum was isolated from cutaneous lesions, a lymph node, and the right eye of a male patient with acquired immunodeficiency syndrome and also from a cervical lymph node in a 3-year-old girl. These two cases are the first M. haemophilum infections to be reported in Canada.
Phenotype and genotype of Escherichia coli isolated from pigs with postweaning diarrhea in Hungary
Authors: Nagy B , Casey T A , Moon H W
Published: January 2020

A total of 205 Escherichia coli isolates from 88 diarrheal weanling (4- to 10-week-old) pigs from 59 farms were tested by slide agglutination for K88, K99, F41, and 987P antigens. K88 antigen was detected in 61% of the isolates representing 60% of the pigs and 56% of the farms. K88 antigen was associated with serogroup O149 and 91% of the K88+ isolates. K99, F41, and 987P were not detected. Of the K88- isolates, 70 were additionally tested by colony hybridization with DNA probes for adherence factors K88, K99, 987P, and F41 and for enterotoxin genes STaP, STaH, STb, and LT and by Vero cell assay for verotoxins (VT). The 70 K88- isolates could be divided into three categories: LT-, VT-, STaP+, and/or STb+ (34 isolates); LT-, STaP+, STb+, and/or VT+ (17 isolates); and nontoxigenic (19 isolates). Only one of the K88- isolates carried a known adherence factor (987P) detectable with DNA probes. Most of the STaP+ and STb+ isolates belonged to O groups O141, O147, and O157. All but 1 of the 17 VT+ isolates belonged to O groups O138, O139, O141, and O149. Only three of the VT+ strains were isolated from pigs with edema disease. We concluded that 73% of the K88- isolates had the capability to produce enterotoxins or VT that could have contributed to weanling pig diarrhea.
Comparisons of Pasteurella multocida lipopolysaccharides by sodium dodecyl sulfate-polyacrylamide gel electrophoresis to determine relationship between group B and E hemorrhagic septicemia strains and serologically related group A strains
Authors: Rimler R B
Published: January 2020

Lipopolysaccharides (LPSs) purified from 16 reference somatic serotypes of Pasteurella multocida were examined and compared by discontinuous sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Resolution of LPS patterns in a gel was optimum when sample wells were cast separately from the stacking gel and the running gel consisted of 15% T (total monomer) polyacrylamide and 4 M deionized urea. Band patterns of P. multocida LPSs in a gel differed from control Salmonella minnesota wild-type and core mutant LPSs. Although the band patterns and mobilities of LPSs from some P. multocida reference serotypes were similar, none were identical. Evidence for O antigens similar to those produced by enterobacteria was not observed. Proteinase K digestion of whole P. multocida cells resulted in LPS band patterns similar to those of purified LPS. The presence or absence of a capsule on a strain had no major influence on band patterns in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Comparisons of LPS patterns of group B and E hemorrhagic septicemia strains with those of serologically related group A strains of P. multocida indicated that they were similar. Typing antisera made with purified serotype 2 or 5 LPS reacted with electroblots of all these strains. However, the reactions did not distinguish strains as being serotype 2 or 5.
Heat stability of protective antigen of Leptospira interrogans serovar lai
Authors: Masuzawa T , Nakamura R , Shimizu T , Yanagihara Y
Published: January 2020

Protective antigen (PAg; glycolipid antigen; molecular size, 23 to 30 kilodaltons), the serogroup-specific antigen partially purified from leptospiral cells, is one of the most important protective antigens. The heat stability of PAg was compared with that of whole-cell (WC) antigen by using sodium dodecyl sulfate-polyacrylamide gel electrophoresis, immunoblotting, protective activity, opsonin-inducing activity, agglutinating antibody-inducing activity, and an inhibition test in an enzyme-linked immunosorbent assay. A band of 23 to 30 kilodaltons of PAg, which was seen in untreated PAg and WC, shifted to a position with a molecular size of ca. 20 kilodaltons after heat treatment of PAg at 80 degrees C for 30 min and WC at 100 degrees C for 30 min. In the enzyme-linked immunosorbent assay inhibition test with monoclonal antibody LW2 and a sonicated antigen of WC, the inhibition rate of PAg and WC to sonicated WC was reduced by heat treatment at 80 degrees C for 30 min and at 100 degrees C for 30 min, respectively. Agglutinating antibody-inducing activities and opsonin-inducing activities of PAg and WC in mice were reduced by heat treatment under the same conditions; these activities were assayed by a microscopic agglutination test and by chemical luminescence response in serum from immunized mice, respectively. Protective activity of heated PAg and heated WC in cyclophosphamide-pretreated mice agreed with the results of immunogenicity in mice. These results indicate that the Leptospira PAg is one of the important protective antigens and is altered by heat treatment at 80 degrees C. Furthermore, the immunogenicity and antigenicity of the PAg present in WC are more stable than that of the extracted PAg, and the coexistence of other cellular components with PAg might protect and stabilize PAg from the heat treatment.
Biochemical and chemical characterization of pink-pigmented oxidative bacteria
Authors: Wallace P L , Hollis D G , Weaver R E , Moss C W
Published: January 2020

The biochemical and chemical characteristics were determined for 156 clinical isolates of pink-pigmented bacteria that are similar to but distinct from Methylobacterium extorquens (synonymous with Pseudomonas mesophilica). These isolates were gram-negative, nonfermentative, usually nonvacuolated, coccoid rods; all grew at 35 degrees C and were catalase and urease positive; the majority grew on MacConkey agar and were variable for oxidase production and motility. On the basis of oxidation of xylose and mannitol and hydrolysis of esculin, these 156 strains were subdivided into four groups that were designated "pink coccoid" groups I, II, III, and IV. Groups I, II, and III are similar to an unnamed taxon described by Gilardi and Faur in 1984; only strains of group IV hydrolyze esculin. The cellular fatty acid compositions of strains of groups I, II, and III were essentially identical and differed from strains of group IV by the absence of 3-OH-C14:0 and the presence of C19:0 delta and 2-OH-C19:0 delta. The fatty acid composition of group IV strains was most similar to that of M. extorquens but differed by the presence of small amounts of two C17:1 acids, 3-OH-C16:0, and 2-OH-C18:1.
Microculture assay for isolation of human immunodeficiency virus type 1 and for titration of infected peripheral blood mononuclear cells
Authors: Dimitrov D H , Melnick J L , Hollinger F B
Published: January 2020

To define the optimal conditions for human immunodeficiency virus (HIV) detection in microcultures, experiments were conducted with different ratios of patient and donor peripheral blood mononuclear cells (PBMCs). Donor/patient PBMC ratios ranged from 1:1 to 1:125. Optimal results were obtained when 1,500,000 donor cells were cocultured with equal or smaller quantities of patient PBMCs. Thus, virologic endpoints could be achieved by diluting patient cells. Smaller numbers of donor cells, with or without larger numbers of patients cells, resulted in lower rates of HIV isolation. Similarly, the direct stimulation of patient PBMCs with phytohemagglutinin without the addition of normal donor cells lowered the sensitivity of the assay significantly. We suggest that a microculture procedure using a fixed quantity of donor cells with different dilutions of patient cells may be useful for monitoring changing HIV levels during antiviral therapy.
Immunoglobulin A and immunoglobulin G antibody responses to alginates from Pseudomonas aeruginosa in patients with cystic fibrosis
Authors: Pedersen S S , Espersen F , Høiby N , Jensen T
Published: January 2020

Patients with cystic fibrosis have a high prevalence of mucoid, alginate-producing Pseudomonas aeruginosa that causes chronic infection of the mucosal surface of the lungs. We developed enzyme-linked immunosorbent assays (ELISAs) for determination in serum of immunoglobulin A (IgA) and IgG antibodies to alginate purified from P. aeruginosa and an ELISA for detection of IgA antibodies to a polyvalent P. aeruginosa standard antigen. Absorption experiments indicated that the assays were antigen and antibody specific and had analytical variations that ranged from 7 to 19%. Serum samples from 207 patients with cystic fibrosis, 100 healthy children, and 94 healthy adults were examined. The patients responded to P. aeruginosa infection with early IgA and IgG antibody responses that were significantly higher than in controls and noncolonized patients. Analysis of paired serum samples showed that infected patients had an increase in specific IgG and IgA antibodies that was significantly higher than in noncolonized patients. The serological data were analyzed for correlation with clinical condition; poor lung function was significantly associated with increased levels of IgA and IgG antibodies to P. aeruginosa alginate and to the standard antigen and with a relative excess of IgA antibodies to the standard antigen compared with IgA antibodies to P. aeruginosa alginate. The assays showed high predictive values if positive, but a negative test did not exclude infection, and the ELISAs should not be used for diagnostic purposes. Mucoid strains were present initially in the sputa of 28 of 54 infected patients with paired serum samples. These patients had a significant increase in anti-alginate antibodies, but it was not different from the increase seen in patients infected only with nonmucoid strains. Therefore, alginate may also be produced in vivo by nonmucoid P. aeruginosa. The study showed that early formation of IgA and IgG antibodies to P. aeruginosa alginate did not prevent development of chronic infection and that P. aeruginosa-specific IgA antibodies correlate with poor lung function.
Analysis of antibody responses to phenotypically distinct lentiviruses
Authors: Kajikawa O , Lairmore M D , DeMartini J C
Published: January 2020

To define the immune responses against phenotypically and pathogenically distinct lentiviruses, we used an immunoblotting assay to study antibodies to viral proteins of ovine lentivirus (OvLV) in 16 experimentally and 12 naturally infected sheep. Two distinct phenotypes of OvLV were used to experimentally infect lambs: strain 85/34, a "rapid/high" isolate which rapidly induced lysis in infected primary macrophage cultures and replicated to relatively high titers, and strains 84/28 and 85/14, "slow/low" isolates which induced slowly progressive syncytia with minimal lysis in vitro and replicated only to low titers in the same cell type. Serum antibodies against four major viral structural proteins, gp105, p25, p16, and p14, were detected. In a longitudinal study of experimentally infected lambs, the antibody to p25 (major gag protein) usually appeared first (average, about 3 weeks postinoculation [p.i.]) and was followed in about 2 weeks by p16, p14, and gp105 almost simultaneously. Six of 16 animals did not develop anti-p14 antibody by the time of necropsy at 9 to 29 weeks p.i. Two of 10 lambs which developed antibody to p14 had the antibody only transiently from 3 to 8 or 13 weeks p.i. and lost it by the time of necropsy at 21 or 22 weeks p.i. In contrast, antibodies to the other three structural proteins remained fairly constant until the time of necropsy. There were differences in the antibody responses of the experimentally infected lambs to the two phenotypes of OvLV. Seven of 10 (70%) lambs which were inoculated with the rapid/high strain developed antibody to p14, whereas only 17% of the lambs inoculated with the slow/low strains had antibody to this protein. In the longitudinal study, no decline was observed in the activity of any specific antibody such as that which occurs with anti-p24 antibody in human immunodeficiency virus infection, except in the case of anti-p14 antibody in two lambs. There were no significant differences in antibody titers against p25, p16, and p14 in final blood samples between rapid/high virus- and slow/low virus-infected groups. However, the rapid/high virus-infected group developed a fivefold-higher geometric mean titer of anti-env product (gp 105) antibody than did the slow/low virus-infected group (P </= 0.1). Antibody titers to all major structural proteins, except p14, in the naturally infected sheep were markedly lower than those in experimentally induced OvLV infections (P </= 0.01). The failure of the slow/low virus-infected group to develop anti-p14 antibody may suggest diminished viral replication in vivo or a failure of the host to recognize p14 in the slow/low virus-infected group. Since the geometric mean antibody titer to gp105 was threefold higher in lambs with lymphoid interstitial pneumonia than in those without lesions and since no differences were observed in the titers of other antiviral antibodies between these groups, we found no evidence to suggest that levels of such antibodies correlated with protection from OvLV-induced disease.
Cluster of antibiotic-resistant Salmonella enteritidis infections in the Central African Republic
Authors: Georges-Courbot M C , Wachsmuth I K , Bouquety J C , Siopathis M R , Cameron D N , Georges A J
Published: January 2020

Salmonella enteritidis strains which are multiply resistant to antimicrobial agents were isolated from the blood of 12 patients hospitalized at the Institut Pasteur of Bangui, Central African Republic, during a 4.5-month period. The lack of gas production in Kligler-Hajna medium initially suggested Salmonella typhi, but isolates were confirmed as unusual S. enteritidis strains. The occurrence of these unique strains in an unusual site of infection may indicate an epidemic due to an unusually invasive and resistant strain of S. enteritidis. Some variation in plasmid profile and susceptibility to antimicrobial agents was noted, possibly reflecting antibiotic pressures existing in the Central African Republic. All isolates were of the same bacteriophage lysis pattern, unlike patterns documented for recent U.S. and European isolates of S. enteritidis.
Effect of patient characteristics on performance of an enzyme immunoassay for detecting cervical Chlamydia trachomatis infection
Authors: Magder L S , Klontz K C , Bush L H , Barnes R C
Published: January 2020

We compared the performance of a commercial enzyme immunoassay (EIA) (Chlamydiazyme; Abbott Diagnostics, North Chicago, Ill.) with that of cell culture for the detection of Chlamydia trachomatis cervical infection in 1,417 women attending public health clinics. Confirmatory chlamydial testing by a direct fluorescent-antibody test (MicroTrak; Syva Co., Palo Alto, Calif.) was performed on specimens from women who had positive EIAs. Overall, only 57% of women who had a positive chlamydial test by cell culture were also positive by EIA. We noted a strong association between the number of chlamydial inclusions in cell culture and a positive EIA outcome. The proportion of culture-positive women who also had a positive EIA declined with age and a history of previous sexually transmitted disease and increased among oral contraceptive users. The results of direct fluorescent-antibody confirmatory testing suggested that cell culture was also insensitive for the detection of C. trachomatis infection. Our observations demonstrate that the performance of the chlamydial EIA may vary greatly with individual patient characteristics and that the utility of EIA as a screening test may be limited, especially in older women.
Leakage of virus through used vinyl and latex examination gloves
Authors: Korniewicz D M , Laughon B E , Cyr W H , Lytle C D , Larson E
Published: January 2020

A total of 480 examination gloves (240 vinyl and 240 latex) were stressed by using manipulations designed to mimic patient care. At the highest use level, 38 (63%) of 60 vinyl gloves leaked bacteriophage phi X174 compared with 4 (7%) of 60 latex gloves. At lower use levels, there was no statistically significant difference in leakage.
Prevalence of seroreactors to the 104-kilodalton hemolysin of Actinobacillus pleuropneumoniae in swine herds
Authors: Devenish J , Rosendal S , Bossé J T , Wilkie B N , Johnson R
Published: January 2020

A rabbit homologous polyclonal antiserum to the 104-kilodalton hemolysin of Actinobacillus pleuropneumoniae serotype 1 strain CM-5 was specifically produced and used in an antigen capture enzyme-linked immunosorbent assay (ELISA) to detect swine serum antibodies to this potentially important virulence factor. Sera from pigs experimentally infected with the most common disease-producing serotypes (serotypes 1, 2, 5, and 7) of A. pleuropneumoniae produced positive results in this ELISA. Of 144 serum samples collected from 10 herds free of pleuropneumonia and 155 serum samples from 11 herds with a history of the disease, 68 (47%) and 148 (95%), respectively, were found positive by the ELISA. In addition, pigs naturally infected with Actinobacillus suis produced antibodies which seroreacted in this ELISA. The results indicated that a high proportion of swine have antibodies seroreactive with the 104-kilodalton hemolysin produced by A. pleuropneumoniae.
Isolation of a previously undescribed rickettsia from an aborted bovine fetus
Authors: Dilbeck P M , Evermann J F , Crawford T B , Ward A C , Leathers C W , Holland C J , Mebus C A , Logan L L , Rurangirwa F R , McGuire T C
Published: January 2020

A previously undescribed obligate intracellular bacterium was isolated from an aborted bovine fetus. The organism was resistant to penicillin, replicated within cytoplasmic vacuoles, exhibited structural characteristics compatible with the rickettsias, and shared antigenic determinants with Cowdria ruminantium.
Culture confirmation of Campylobacter spp. by latex agglutination
Authors: Nachamkin I , Barbagallo S
Published: January 2020

A commercial latex agglutination test [Meritec-Campy (jcl), Meridian Diagnostics, Cincinnati, Ohio] was evaluated for identification of Campylobacter jejuni, C. coli, C. laridis, and other Campylobacter isolates. The test had 100% sensitivity in detecting C. jejuni and C. coli but low sensitivity with C. laridis isolates. C. upsaliensis strains reacted with the test. The test had 100% specificity for 101 non-Campylobacter organisms.