Biomedical subjects

R E Weaver

Publications and source records attributed to R E Weaver.

At least 37 records · Page 2Linked to original sources

PubMed1991

Evaluation of hybridization characteristics of a cloned pRF106 probe for Listeria monocytogenes detection and development of a nonisotopic colony hybridization assay.

An internal fragment (pRF106 fragment, ca. 500 bp) of a gene (msp) coding for a 60-kDa protein of Listeria monocytogenes serotype 1/2a was used to develop a screening method to discriminate between L. monocytogenes and avirulent Listeria spp. on primary isolation plates. The L. monocytogenes-derived probe fragment of pRF106 hybridized to a 13-kb fragment of L. monocytogenes and a 3-kb fragment of one cheese isolate strain of Listeria seeligeri under stringent hybridization conditions (mean thermal denaturation temperature [Tm]-5 degrees C). The probe also hybridized to a 6-kb fragment of Listeria innocua, Listeria ivanovii, and L. seeligeri under less stringent hybridization conditions (Tm-17 degrees C). The pRF106 fragment was labeled with digoxigenin-11-dUTP and used to develop a colony hybridization assay. Colonies from lithium chloride-phenylethanol-moxalactam agar were blotted onto nylon membranes. The cells were pretreated with microwaves before lysis with sodium hydroxide. DNA-DNA hybridization and posthybridization washing were done at high stringency (Tm-7 degrees C). The nonisotopic colony hybridization procedure was specific for L. monocytogenes when evaluated against pure cultures of L. monocytogenes and other Listeria species, excluding the cheese isolate of L. seeligeri. Also, it was specific for L. monocytogenes when evaluated with Listeria-negative food enrichment cultures that were inoculated in the laboratory with Listeria species.

DNA Probes↗

PubMed1991

Comparison of cold enrichment and U.S. Department of Agriculture methods for isolating Listeria monocytogenes from naturally contaminated foods. The Listeria Study Group.

We compared the cold enrichment (CE) and U.S. Department of Agriculture (USDA) methods for isolating Listeria monocytogenes by examining 402 food samples. The food samples were collected from refrigerators of listeriosis patients as part of a multistate active surveillance project to determine the role of foods in sporadic listeriosis in the United States. L. monocytogenes was isolated from 51 food samples (13%). The USDA method was significantly better (P less than 0.001) than the CE method. The isolation efficiencies of the USDA and CE methods were 96 and 59%, respectively. Quantitation of L. monocytogenes in the food samples revealed that many food samples containing less than 0.3 CFU/g were negative as determined by the CE method but positive as determined by the USDA method.

Cold Temperature↗

PubMed1991

Actinobacillus spp. and related bacteria in infected wounds of humans bitten by horses and sheep.

We describe the isolation of Actinobacillus lignieresii and an A. equuli-like bacterium from an infected horse-bite wound in a 22-year-old stable foreman and A. suis from a bite injury in a 35-year-old man who had been attacked by a horse. A. lignieresii was also isolated in pure culture from an infected sheep-bite wound in a rural worker. These species of the genus Actinobacillus are primarily associated with animals and animal diseases and are rarely isolated from humans. The purpose of this report is to raise awareness of the possible occurrence of Actinobacillus spp. in bite wounds inflicted by farm animals and to discuss the difficulties encountered in the identification of species of Actinobacillus and related bacteria.

Actinobacillus↗

PubMed1991

Cytopathogenic effects in enterocytelike Caco-2 cells differentiate virulent from avirulent Listeria strains.

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

Animals↗

PubMed1991

Molecular characterization and proposal of a neotype strain for Bartonella bacilliformis.

Bartonella bacilliformis, the etiologic agent of bartonellosis, was characterized biochemically and by DNA hybridization, guanine-plus-cytosine content, genome size, and 16S rRNA sequencing. DNAs from the two strains in our collection exhibited 97% relatedness in hydroxyapatite reactions done at 55 degrees C (optimal reassociation criterion) and 100% relatedness in reactions done at 70 degrees C (stringent reassociation criterion). There was no evidence of divergence within the related sequences. B. bacilliformis DNA showed no relatedness to the cat scratch disease bacillus or to a strain of a second species in the same genus as the cat scratch disease bacillus in hybridization reactions done at 65 degrees C. The guanine-plus-cytosine contents of DNAs from the two B. bacilliformis strains were 39 and 40 mol%. Time course reassociation, done by determining spectrophotometrically the time required for one-half of the denatured DNA to form duplexes, indicated that B. bacilliformis has a genome size of approximately 4 x 10(8). The 16S rRNA sequence analysis indicated that B. bacilliformis is in the alpha-2 subgroup of the purple bacteria, class Proteobacteria, and that its closest relatives are Rochalimaea quintana and Brucella abortus. Strain KC583 (= Herrer 020/F12,63 = ATCC 35685) is proposed as the type strain of B. bacilliformis.

Bartonella↗

PubMed1990

Neisseria elongata subsp. nitroreducens subsp. nov., formerly CDC group M-6, a gram-negative bacterium associated with endocarditis.

CDC group M-6 is the vernacular name given to a gram-negative, oxidase-positive, aerobic, nonmotile, rod-shaped bacterium. This organism is biochemically similar to Kingella denitrificans and displays a cellular fatty acid profile consistent with CDC groups M-5 and EF-4 and with Neisseria elongata. Of the 95 M-6 strains referred to the Centers for Disease Control (CDC) for identification, 32 (64%) of the first 50 were from the throat or sputum and only 3 (6%) were from blood; only 5 (11%) of the next 45 isolates were from the upper respiratory tract and 23 (51%) were from blood, with many of these (15 or 65%) being associated with endocarditis. The major characteristics of CDC group M-6 include reduction of nitrate and nitrite with no gas formation; positive reaction for oxidase; negative reactions for catalase, urease, indole, and motility; and no acid production from carbohydrates. Guanine-plus-cytosine content determined spectrophotometrically by thermal denaturation was 55 to 58 mol % for six M-6 strains tested: 56 mol % for the N. elongata subsp. elongata type strain and for the N. elongata subsp. glycolytica type strain. By the hydroxyapatite method, DNAs from 24 M-6 strains showed an average of 78% relatedness to M-6 reference strain B1019 in reactions at 60 degrees C and 73% relatedness in reactions at 75 degrees C. M-6 strain B1019 was 79% related to the N. elongata type strain at 60 degrees C and 71% related at 75 degrees C; it was 75% related to the type strain N. elongata subsp. glycolytica at 60 degrees C and was 66% related at 75 degrees C. DNAs from CDC group EF-4, K. denitrificans, and CDC group M-5 were all less than 14% related to CDC group M-6 at 75 degrees C. The DNA relatedness data showed conclusively that all the M-6 strains belong in the species N. elongata. M-6 is different from N. elongata subsp. elongata in that M-6 reduces nitrate and sometimes weakly acidifies D-glucose, and it is different from N. elongata subsp. glycolytica in that it reduces nitrate and is negative for glucose and catalase. Because of the apparent clinical significance of M-6 compared with the clinical significance of N. elongata subsp. elongata and N. elongata subsp. glycolytica and the ease in distinguishing it biochemically, we propose M-6 as a third subspecies of N.elongata, N. elongata subsp. nitroreducens subsp. nov.

Adult↗

PubMed1990

Biochemical and chemical characterization of pink-pigmented oxidative bacteria.

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.

Fatty Acids↗

PubMed1989

Infection caused by Francisella philomiragia (formerly Yersinia philomiragia). A newly recognized human pathogen.

We evaluated the clinical characteristics of patients with Francisella philomiragia (formerly Yersinia philomiragia) isolated from normally sterile sites. Isolates from 14 patients were received by the Centers for Disease Control between 1975 and 1987: 9 were from blood; 2 from lung biopsies; and 1 each from pleural, peritoneal, and cerebrospinal fluid. Underlying problems included chronic granulomatous disease in 5 patients, near-drowning in 5, and a myeloproliferative disease in 2. All 13 patients for whom records were available had a febrile syndrome compatible with bacterial infection. Pneumonia and fever-bacteremia were the commonest clinical syndromes reported. In 7 cases, F. philomiragia was the only sterile-site isolate, and the clinical syndrome did not resolve without appropriate antibiotics. Familiarity with this organism is important because of its ability to cause serious disease in chronic granulomatous disease and near-drowning patients. Further study may yield new insights into pathogenic and host defense mechanisms.

Adolescent↗

PubMed1989

Analysis of Listeria monocytogenes by multilocus enzyme electrophoresis and application of the method to epidemiologic investigations.

We examined 310 strains of Listeria monocytogenes by multilocus enzyme electrophoresis. Fifty-six electrophoretic types (ETs) of the organism were defined: 10 for serovar 4b strains, 11 for serovar 1/2b strains, and 30 for serovar 1/2a strains. Strains of serovars 1/2c, 3a, and 3b, and a non-typable strain were distributed among the remaining five ETs. The mean genetic diversity of the species was 0.41. Principal coordinate analysis revealed a sharp division among ETs which divided the species into two major clusters. ETs containing serovar 1/2a strains were in one cluster while all ETs containing serovar 4b, 1/2b, and 3b strains were in the second cluster. Except for two ETs that contained strains from both serovar 1/2b and serovar 3b, no ET contained strains from more than one serovar. Multilocus enzyme electrophoresis facilitated the analysis of epidemiologic data. In three separate epidemiologic investigations electrophoretic typing confirmed a common source as a cause of an outbreak; in a fourth investigation a single common source as a cause of an outbreak was effectively ruled out. Electrophoretic typing was also useful in documenting potential links between Listeria contaminated foods and persons with listeriosis who consumed those foods.

Animals↗

PubMed1989

BRO beta-lactamases of Branhamella catarrhalis and Moraxella subgenus Moraxella, including evidence for chromosomal beta-lactamase transfer by conjugation in B. catarrhalis, M. nonliquefaciens, and M. lacunata.

Two closely related beta-lactamases, BRO-1 and BRO-2 (formerly called Ravasio and 1908), are found in Moraxella (Branhamella) catarrhalis. We screened strains of B. catarrhalis recovered in the United States since 1952 and identified the first beta-lactamase-positive isolate in August 1976. The prevalence of the enzymes among 394 clinical isolates from one Texas hospital has averaged 75% since testing began in 1983. Screening of isolates of Moraxella subgenus Moraxella revealed the BRO enzymes in two other human respiratory tract species, M. lacunata and M. nonliquefaciens, beginning in 1978. A different beta-lactamase with a pI of 6.4 predominated in other species of subgenus Moraxella. BRO-2 had a different isoelectric focusing pattern and was produced in lesser amounts than BRO-1, but the two enzymes were indistinguishable by substrate or inhibitor profile. BRO enzymes from B. catarrhalis, M. nonliquefaciens, and M. lacunata could be transferred by conjugation and, for B. catarrhalis, also by transformation to B. catarrhalis. Plasmid bands were demonstrated in 90% of M. nonliquefaciens and in one previously reported strain of B. catarrhalis, but no change in plasmid profiles was seen in beta-lactamase-positive recombinants, supporting previous studies that suggested the beta-lactamase genes are chromosomal.

Chromosomes, Bacterial↗

PubMed1989

Capnocytophaga canimorsus sp. nov. (formerly CDC group DF-2), a cause of septicemia following dog bite, and C. cynodegmi sp. nov., a cause of localized wound infection following dog bite.

CDC group DF-2 is the vernacular name given to a slow-growing gram-negative bacterium that causes septicemia and meningitis in humans. Infections frequently (one-third of cases) occur following dog bites or close contact with dogs or occasionally with cats. Splenectomy and alcoholism appear to be strong predisposing factors for DF-2 infection. In addition to 150 DF-2 strains received for identification, we received 9 DF-2-like strains; 6 were isolated from wound or eye infections, 3 of which were associated with dog bites and 1 of which was associated with a cat scratch, and 3 were isolated from dog mouths. The major characteristics of DF-2 include production of acid but no gas from lactose and maltose and usually D-glucose; positive reactions for oxidase, catalase, arginine dihydrolase, gliding motility, and o-nitrophenyl-beta-D-galactopyranoside; growth enhanced by serum and by incubation in a candle jar atmosphere; and negative reactions for sucrose, raffinose, inulin, melibiose, nitrate reduction, indole, and growth on MacConkey agar. DF-2-like strains had the same characteristics, except that acid was formed from sucrose, raffinose, inulin, and melibiose. By the hydroxyapatite method, DNAs from 12 DF-2 strains were 88% related in 60 degrees C reactions and 84% related in 75 degrees C reactions. Related sequences contained 0.5 to 1.5% unpaired bases (divergence). Three DF-2-like strains were 73 to 80% related at 60 degrees C (with 2.0 to 2.5% divergence) and 68 to 75% related at 75 degrees C. The relatedness of DF-2 and DF-2-like strains was 19 to 31% at 60 degrees Celsius and 13 to 19% at 75 degrees Celsius. The relatedness of DF-2 and DF-2-like strains to Capnocytophaga species was 4 to 7%. The DNA relatedness date indicate that eh DF-2 and the DF-2-like strains are separate, previously undescribed species. Both groups are phenotypically and genetically distinct from Capnocytophaga species, although they do share several characteristics with Capnocytophaga species, including cellular morphology, gliding motility, cellular fatty acid composition, enhancement of growth in a candle jar atmosphere, and G+C content. The new species differ from Capnocytophaga species by their positive oxidase and catalase reactions. We chose to avoid creating a new genus and proposed the names Capnocytophaga canimorsus sp. nov. for group DF-2 and C. cynodegmi sp. nov. for the DF-2-like strains.

Adult↗

PubMed1989

Recovery of Pseudomonas gladioli from respiratory tract specimens of patients with cystic fibrosis.

Pseudomonas gladioli was isolated from 11 patients with cystic fibrosis. It resembled Pseudomonas cepacia on the selective and differential medium OFPBL, producing yellow colonies after 48 to 72 h of incubation. Isolates were characterized biochemically, by DNA hybridization, and by cellular fatty acid analysis. A review of the clinical status of selected patients colonized by P. gladioli did not reveal any apparent association of this organism with infectious complications of cystic fibrosis. Thus, the clinical implications may differ depending on which of these two closely related species is reported by laboratories. Determination of the fatty acid profile of isolates by gas chromatography may be a useful adjunct to biochemical characterization as a means of identification. In contrast to P. cepacia, most isolates of P. gladioli contained 3-OH C10:0 fatty acid under the growth conditions used.

Adolescent↗

PubMed1989

Characterization of CDC group DF-3 by cellular fatty acid analysis.

Fourteen strains of Centers for Disease Control group DF-3 bacteria were examined for cellular fatty acid composition to evaluate their chemical relatedness to known bacterial species and groups. The fatty acids were liberated from whole cells by base hydrolysis, methylated, and analyzed by capillary gas-liquid chromatography. All group DF-3 strains possessed a distinct fatty acid profile which was characterized by large amounts (24%) of 12-methyltetradecanoate (a-C15:0), moderate amounts of saturated iso-branched-chain acids (i-C14:0 and i-C15:0), and small to moderate amounts of both branched- and straight-chain hydroxy acids (3-OH C15:0, i-3-OH C16:0, 3-OH C16:0, and i-3-OH C17:0). This fatty acid profile was unique as compared with the profiles of other bacteria we have previously tested but was most similar to the profiles of Capnocytophaga species.

Capnocytophaga↗

PubMed1989

Serological classification of Xanthomonas maltophilia (Pseudomonas maltophilia) based on heat-stable O antigens.

Twenty-six serotypes of Xanthomonas maltophilia were defined by using 15 antisera described by Hugh and Ryschenkow (R. Hugh and E. Ryschenkow, J. Gen. Microbiol. 26:123-132, 1961) and 11 new antisera. The antisera were prepared by immunizing rabbits with bacterial strains heated at 100 degrees C for 2 h. Twelve antisera required adsorptions with cross-reacting heterologous immunizing strains. We tested 275 clinical and environmental strains of X. maltophilia with 26 antisera by the slide agglutination technique. A total of 259 (94.2%) strains were typeable, with 137 (49.8%) strains agglutinating in three antisera.

Agglutination Tests↗

PubMed1989

CDC group HB-5 as a cause of genitourinary infections in adults.

Isolates from five patients with genitourinary infections diagnosed over a 7-week period were identified as CDC group HB-5. The organisms caused clinical presentations of pelvic inflammatory disease in three women and urethritis in the only male in the series. The remaining patient received surgical treatment for a Bartholin gland abscess. Since the clinical and temporal presentations were remarkable and the questions of sexual mode of transmission and strain relatedness were of concern, the five strains were examined further by multilocus enzyme electrophoresis and ribosomal DNA typing. Overall, the five clinical isolates were more closely related to each other than to the control strains. This is the first report describing genitourinary infections caused by group HB-5. While the pathophysiology of group HB-5 infections remains to be fully elucidated, the possibility that this organism may be sexually transmitted deserves further study.

Abscess↗

PubMed1989

Francisella philomiragia comb. nov. (formerly Yersinia philomiragia) and Francisella tularensis biogroup novicida (formerly Francisella novicida) associated with human disease.

Over a 12-year period, 16 human strains of a gram-negative, catalase-positive, halophilic, aerobic, nonmotile, small coccoid bacterium were received for identification. On the bases of biochemical characteristics and cellular fatty acid profiles, 14 of these strains were similar to the "Philomiragia" bacterium (Yersinia philomiragia, species incertae sedis). Additional characteristics were growth on Thayer-Martin agar but no growth or sparse, delayed growth on MacConkey agar; oxidase positive; acid production, often weak and delayed, from D-glucose, sucrose, and maltose; urease negative; no reduction of nitrates; and H2S produced but often delayed in triple sugar iron agar. Both the human isolates and the "Philomiragia" bacterium contained C10:0, C14:0, C16:0, C18:1 omega 9c, C18:0, 3-OH C18:0, C22:0, and C24:1 as major cellular fatty acids and ubiquinone eight (Q8) as the major isoprenoid quinone. These cellular acids in these relative amounts have been found previously only in Francisella tularensis and Francisella novicida, suggesting a relationship between the "Philomiragia" bacterium and Francisella species. Of the 14 human "Philomiragia"-like isolates, 9 were from blood, 3 were from lung biopsies or pleural fluid, and one each was from peritoneal fluid and cerebrospinal fluid. DNA relatedness studies (hydroxyapatite method, 50 and 65 degrees C) showed that these 14 strains were a single group that was the same species as the "Philomiragia" bacterium. Two other human strains were oxidase negative and H2S negative. They formed a single DNA relatedness group that was indistinguishable from the type strains of both F. tularensis and F. novicida. DNA relatedness of "Philomiragia" bacterium type and other strains to strains of F. novicida and F. tularensis, including the type strains, was 35 to 46%. One of the two F. novicida- and F. tularensis-like strains was isolated from blood, and the other was isolated from a cervical lymph node. On the basis of these findings, we propose transferring Y. philomiragia from the genus Yersinia to the genus Francisella as Francisella philomiragia comb. nov. Having confirmed that F novicida and F. tularensis are the same species and having shown that F. novicida is pathogenic for humans, we further propose eliminating the species F. novicida and demoting it to a biogroup of F. tularensis.

Adult↗

PubMed1988

Cultural and chemical characterization of CDC groups EO-2, M-5, and M-6, Moraxella (Moraxella) species, Oligella urethralis, Acinetobacter species, and Psychrobacter immobilis.

We determined phenotypic characteristics, cellular fatty acid composition, and isoprenoid quinone content of representative strains of CDC groups EO-2, M-5, and M-6, Moraxella (Moraxella) species, Oligella urethralis, Acinetobacter species, and Psychrobacter immobilis. All organisms contained ubiquinone with eight isoprene units as the major isoprenolog, but distinct differences were observed in fatty acid composition. Twenty-eight of the original collection of CDC group EO-2 strains were further identified as P. immobilis, EO-2, or EO-3 by distinctive cellular fatty acid profiles, cellular morphology, and pigment production. The cellular fatty acid compositions of M-5 and M-6 were similar but were clearly different from those of other organisms. The genus Acinetobacter was differentiated from other organisms in the study by small amounts of 2-hydroxydodecanoic acid (2-OH-12:0), and P. immobilis was differentiated by small amounts of decanoic acid (10:0) and a branched-chain 17-carbon acid (i-17:0). All Moraxella species were distinguished by small amounts of decanoic acid (10:0) and the absence of i-17:0. M. bovis, M. nonliquefaciens, and some strains of M. lacunata formed a single fatty acid group, while M. osloensis, M. phenylpyruvica, M. atlantae, and other strains of M. lacunata (M. lacunata II) had species-specific fatty acid profiles. O. urethralis differed from Moraxella species by the presence of large amounts (49%) of cis-vaccenic acid (18:1 omega 7c), small amounts (1%) of 3-hydroxyhexadecanoate (3-OH-16:0), and the absence of 10:0 and 3-hydroxydodecanoate (3-OH-12:0). The combined use of chemical data and a small number of conventional tests permitted rapid identification and differentiation of these organisms from each other and from related organisms.

Acinetobacter↗

PubMed1988

Cellular fatty acid composition of Kingella species, Cardiobacterium hominis, and Eikenella corrodens.

We determined the cellular fatty acid composition of reference strains and clinical isolates of each of the three Kingella species, Cardiobacterium hominis, and Eikenella corrodens by using capillary gas chromatography. Kingella denitrificans and Kingella kingae contained myristic (14:0) and palmitic (16:0) acids as major acids, whereas cis-vaccenic (18:1 omega 7c) and palmitic acids were the major acids in Kingella indologenes, C. hominis, and E. corrodens. C. hominis differed from the other four species by the absence of 3-hydroxylauric (3-OH-12:0) acid, from K. indologenes by the presence of 3-hydroxypalmitic (3-OH-16:0) acid, and from E. corrodens by the presence of 3-hydroxymyristic (3-OH-14:0) acid. E. corrodens contained a small amount (2%) of myristic acid, while the other four species contained moderate to large amounts (11 to 31%) of this acid.

Bacteroides↗