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Biomedical subjects

R E Weaver

Publications and source records attributed to R E Weaver.

At least 19 recordsLinked to original sources
PubMed1995

Bordetella holmesii sp. nov., a new gram-negative species associated with septicemia.

CDC nonoxidizer group 2 (NO-2) currently consists of 15 gram-negative, rod-shaped, oxidase-negative, asaccharolytic, brown soluble pigment-producing strains isolated from blood cultures, usually from young adults. On the basis of their cellular fatty acid profiles, NO-2 strains formed a single group that was identical with the profile of Bordetella avium. 16S rRNA sequencing of one NO-2 strain and the type strains of B. pertussis, B. parapertussis, B. bronchiseptica, and B. avium showed a high degree of homology (> or = 98% over 1,525 bases). The NO-2 guanine-plus-cytosine content (61.5 to 62.3 mol%) and major ubiquinone analysis (ubiquinone-8) results were both consistent with those for the genus Bordetella. DNA relatedness studies (hydroxyapatite method) confirmed a close relatedness between NO-2 and Bordetella species and demonstrated that NO-2 strains were a single new species. The name B. holmesii sp. nov. is proposed for CDC group NO-2.

Adolescent↗
PubMed1995

Characterization of Neisseria elongata subsp. glycolytica isolates obtained from human wound specimens and blood cultures.

Four slightly yellow-pigmented, alpha-hemolytic, gram-negative coccobacilli, three from wound specimens and one from multiple blood cultures of a patient with endocarditis, were identified as Neisseria elongata subsp. glycolytica on the basis of their overall biochemical and genetic similarities to this subspecies. These strains resembled N. elongata in their guanine-plus-cytosine contents (55.6 to 57.1 mol%) and in their overall cellular fatty acid profiles, which are characterized by large amounts of 16:0, 16:1 omega 7c, and 18:1 omega 7c fatty acids. Their identities were confirmed by species-level DNA relatedness (hydroxyapatite method) to the type strains of all three N. elongata subspecies. The biochemical profiles and cultural characteristics of these strains resembled those of the type strain of N. elongata subsp. glycolytica except for the production of a weak yellow growth pigment and alpha-hemolysis on sheep blood agar. They differed from N elongata subsp. elongata by the production of catalase, by the production of alpha-hemolysis on sheep blood agar, and by acid production from D-glucose. They differed from N. elongata subsp. nitroreducens by the production of catalase and an inability to reduce nitrate. These studies suggest a pathogenic potential for N. elongata subsp. glycolytica, usually considered to be a transient colonizer in humans.

Bacterial Typing Techniques↗
PubMed1994

Prevalence of Neisseria meningitidis relatively resistant to penicillin in the United States, 1991. Meningococcal Disease Study Group.

To estimate the prevalence of Neisseria meningitidis relatively resistant to penicillin in the United States, antimicrobial susceptibility testing was performed on all US meningococcal isolates submitted to the Centers for Disease Control and Prevention in 1991, including isolates identified through population-based surveillance for invasive meningococcal disease in selected areas of the United States. Three of the 100 isolates tested had MICs of penicillin of 0.125 microgram/mL. All were serogroup B, beta-lactamase-negative, and unique by multilocus enzyme electrophoresis subtyping. None of the 3 patients had been treated solely with penicillin; all recovered completely. About 4% of the isolates obtained from the population-based surveillance system were relatively penicillin-resistant. Given the low prevalence and uncertain clinical significance of infection with these organisms, routine susceptibility testing of meningococcal isolates is not indicated at this time; however, continued surveillance is necessary to monitor trends in antimicrobial susceptibility of meningococci in the United States.

Disease Outbreaks↗
PubMed1994

A point-source foodborne listeriosis outbreak: documented incubation period and possible mild illness.

Listeria bacteremia occurred in 2 pregnant women whose only common exposure was attendance at a party. The incubation period, the possibility of mild disease due to Listeria infection, and foods associated with risk of disease were evaluated. Ten (28%) of 36 party attenders met a case definition, which included isolation of Listeria monocytogenes from blood or stool or two of the following: fever, musculoskeletal symptoms, nausea, vomiting, diarrhea. One of 25 stool cultures was positive. The 2 blood isolates and 1 stool isolate were serotype 4b and identical by enzyme typing. The incubation periods for illness in the 2 pregnant women were 19 and 23 days. Consumption of large amounts of shrimp, nonalcoholic beverages, Camembert cheese, and cauliflower was significantly associated with illness. Eating shrimp remained a significant risk factor for illness after controlling for consumption of other foods. This study suggests a milder illness may exist in healthy persons who consume foods contaminated with L. monocytogenes and demonstrates a prolonged incubation period for disease.

Adult↗
PubMed1994

Comparison of ribotyping and multilocus enzyme electrophoresis for subtyping of Listeria monocytogenes isolates.

Ribotyping was compared with multilocus enzyme electrophoresis (MEE) for subtyping 305 Listeria monocytogenes isolates from clinical and nonclinical sources. For ribotyping, EcoRI-restricted genomic DNA fragments of L. monocytogenes strains were separated by agarose gel electrophoresis, and Southern blots were probed with a cloned Escherichia coli rrnB operon (plasmid pKK3535) labeled with digoxigenin. The L. monocytogenes isolates were divided into 28 distinct ribotypes, while MEE analysis divided the same isolates into 78 electrophoretic types (ETs). On the basis of their ribotype profiles, the strains were divided into two subgroups. The ribotype alpha (RT alpha) subgroup contained serotypes 1/2a, 1/2c, and 3a, and the ribotype beta (RT beta) subgroup contained serotypes 1/2b, 3b, 4b, and 4ab. This division is in complete agreement with MEE analysis, which divides the species into two subgroups (ET groups A and B), with the same serotype distribution in each subgroup. Overall, MEE was more discriminating than ribotyping. However, in several instances ribotyping discriminated between isolates within the same ET. Ribotyping was more discriminating for serotypes 1/2a, 1/2c, and 3a (Simpson's Index for Diversity [DI] = 0.81) than for serotypes 1/2b and 4b (DI = 0.76). A substantial proportion (69%) of serotype 1/2b and 4b strains clustered in five ETs and five ribotypes. These data suggest that ribotyping and MEE do not provide adequate discrimination between strains of serotypes 1/2b and 4b. Methods such as pulsed-field gel electrophoresis and random amplified polymorphic DNA analysis should be explored for further discrimination of strains of these serotypes.

Bacterial Typing Techniques↗
PubMed1994

Human infections caused by Brevibacterium casei, formerly CDC groups B-1 and B-3.

Forty-one clinical strains of CDC coryneform groups B-1 and B-3 were compared biochemically, by analysis of cell wall sugars, amino acids, and cellular fatty acids, and by DNA relatedness to the type strains of Brevibacterium casei, Brevibacterium epidermidis, and Brevibacterium linens. Twenty-two strains were shown to be B. casei, while five other strains formed a phenotypically inseparable genomospecies in the same genus. The remaining isolates were genetically heterogeneous, and most are probably members of the genus Brevibacterium. They were not further identified, but they were biochemically distinguishable from B. casei. Eleven of the clinical strains of B. casei were isolated from blood, and two each were isolated from cerebrospinal fluid and from pleural fluid. At least five isolates were from multiple blood or cerebrospinal fluid cultures. To our knowledge, these strains are the first described clinical isolates identified as B. casei, which was previously considered to be a nonpathogenic species.

Actinomycetales Infections↗
PubMed1994

Recognition of Dermabacter hominis, formerly CDC fermentative coryneform group 3 and group 5, as a potential human pathogen.

Thirty strains of fermentative coryneform-like bacteria designated CDC fermentative coryneform group 3 and coryneform group 5 were compared biochemically by cellular fatty acid analysis and by DNA relatedness with the type strain of Dermabacter hominis, ATCC 49369. DNA from 22 strains of both CDC groups showed 69 to 96% relatedness (hydroxyapatite method) to labeled DNA from ATCC 49369 and to DNA from CDC group 3 strain G4964, and the strains are considered to belong to D. hominis. The remaining eight strains were genetically but not phenotypically differentiable from D. hominis. They were genetically heterogeneous, but hybridization results indicated that they probably belong to the genus Dermabacter. Thirteen of the 22 D. hominis strains and all 8 of the other Dermabacter strains had been isolated from blood, which indicates the pathogenic potential of this species and genus.

Actinomycetales↗
PubMed1993

Roseomonas, a new genus associated with bacteremia and other human infections.

In the 1980s, a pink bacterium different from species of the genus Methylobacterium was implicated in human infection. Using biochemical tests and DNA hybridization, we examined 42 strains of pink-pigmented, gram-negative bacteria that were not members of the genus Methylobacterium. The isolates included 6 strains each of CDC "pink coccoid" groups I, II, III, and IV; 10 isolates from Gilardi's "unnamed taxon"; and 8 blood isolates from ill, debilitated, or immunosuppressed patients. The DNA hybridization studies supported the creation of six genomospecies encompassing the 42 strains. Reactions for esculin hydrolysis, glycerol oxidation, and D-mannose oxidation enabled separation of genomospecies 1 through 4. These tests, as well as motility, nitrate reduction, citrate utilization, and oxidation of L-arabinose, D-galactose, and D-xylose, differentiated genomospecies 5 and 6 from each other and from genomospecies 1 through 4. These organisms were susceptible in vitro to the aminoglycosides, tetracycline, and imipenem and generally susceptible to the quinolones. We propose the new genus, Roseomonas, for these bacteria to include three named species, Roseomonas gilardii sp. nov., Roseomonas cervicalis sp. nov., and Roseomonas fauriae sp. nov., and three unnamed genomospecies.

Bacteremia↗
PubMed1993

Rochalimaea elizabethae sp. nov. isolated from a patient with endocarditis.

A Rochalimaea-like organism (strain F9251) was isolated from a patient with endocarditis after blood drawn for culture before antimicrobial therapy was subcultured onto blood and chocolate agars and incubated for 2 weeks in 5% CO2. The strain was phenotypically similar to known Rochalimaea species. The cellular fatty acid composition of strain F9251 was close to but distinct from those of the three known Rochalimaea species and was most similar to that of R. vinsonii. Labeled DNA from strain F9251 was 59 to 67% related to DNAs from type strains of the three described Rochalimaea species, and its 16S rRNA gene sequence was 98.9% or more homologous to their 16S rRNA gene sequences. These findings support classification of F9251 as a new Rochalimaea species, for which the name Rochalimaea elizabethae sp. nov. is proposed. The patient infected with the organism had large bacterial vegetations on his aortic valve and was cured with antibiotics and valve-replacement surgery. Recognition of the procedures required to identify this and other Rochalimaea species suggests that clinical laboratories should prolong the incubation times of cultures of blood and tissue from patients with suspected endocarditis, patients with fever of unknown origin, and immunocompromised patients with fever so that the full spectrum of disease caused by these organisms can be recognized.

Adult↗
PubMed1993

Neisseria weaveri sp. nov., formerly CDC group M-5, a gram-negative bacterium associated with dog bite wounds.

CDC group M-5 is a rod-shaped, gram-negative, nonmotile bacterium associated with dog bite wounds. DNA-DNA relatedness and biochemical and growth characteristics were studied for 54 strains from the collection at the Centers for Disease Control and Prevention. One typical M-5 strain, 8142, was further studied by 16S rRNA sequencing. DNA from 40 of 53 strains showed 82 to 100% relatedness (hydroxyapatite method) to labeled DNA from strain 8142. The guanine-plus-cytosine (G + C) content in 8 of the 41 highly related M-5 strains was 50.5 to 52 mol%. These 41 strains were oxidase and catalase positive, nonfermentative, nitrite positive, nitrate negative, weakly phenylalanine deaminase positive, aerobic, and alpha-hemolytic (sheep blood). DNA from the 13 remaining strains showed only 7 to 46% DNA relatedness to strain 8142. These 13 non-M-5 strains differed from the M-5 strains in G + C content, growth characteristics, and biochemical profiles. DNA from M-5 strain 8142 was most closely related to DNA from groups EF-4b (47%) and EF-4a (45%). 16S rRNA sequence analysis placed M-5 strain 8142 in the Neisseriaceae cluster of the beta-3 subgroup of the class Proteobacteria. It was most homologous (98.4 to 98.8%) to Neisseria animalis, Neisseria flavescens, Neisseria canis, and Neisseria elongata. All data are consistent with M-5 being a new species of Neisseria, for which we propose the name Neisseria weaveri.

Animals↗
PubMed1992

Role of foods in sporadic listeriosis. II. Microbiologic and epidemiologic investigation. The Listeria Study Group.

OBJECTIVE: To evaluate the role of foods in sporadic listeriosis. DESIGN: Microbiologic survey of foods collected from refrigerators of patients with listeriosis identified through active laboratory-based surveillance. Patient and food Listeria monocytogenes isolates were subtyped to identify foods contaminated with the same strain of L monocytogenes that caused illness in the patient; samples of these foods were obtained from the retail source. SETTING: Multistate population-based study conducted between 1988 and 1990. RESULTS: Listeria monocytogenes grew from at least one food specimen in the refrigerators of 79 (64%) of 123 listeriosis patients; 11% of more than 2000 food specimens collected in the study contained L monocytogenes. Twenty-six (33%) of 79 refrigerators with foods that grew L monocytogenes contained at least one food isolate of the same strain as that in the corresponding patient, a frequency much higher than would be expected by chance (P less than .001). Multivariate analysis showed that of the food specimens that grew L monocytogenes, foods that were ready-to-eat, foods that grew L monocytogenes by a direct-plating method (a measure of the level of contamination), and foods that contained serotype 4b isolates were independently associated with an increased likelihood of containing the patient-matching strain. CONCLUSION: We identified specific food and L monocytogenes isolate characteristics--ready-to-eat foods, foods containing higher concentrations of L monocytogenes, and foods containing serotype 4b--which were associated with disease-causing strains. These results can provide guidance to industry and regulatory agencies in developing strategies to prevent listeriosis.

Food↗
PubMed1992

Chemical and cultural characterization of CDC group WO-1, a weakly oxidative gram-negative group of organisms isolated from clinical sources.

Ninety-six strains of weakly oxidative gram-negative rods isolated primarily from clinical specimens form a distinct group that has been designated Centers for Disease Control (CDC) group WO-1 (WO stands for weak oxidizer). The phenotypic characteristics of CDC group WO-1 were most similar to those of Comamonas acidovorans, Pseudomonas mallei, and CDC pink coccoid group III. The WO-1 group can be differentiated from C. acidovorans by the oxidation of glucose (often weak and sometimes delayed), motility by means of one or two polar flagella, and, when positive, the complete reduction of nitrate and nitrite. Motility and usually the failure to produce arginine dihydrolase distinguish this group from P. mallei. The WO-1 strains differ from the pink coccoid group III by the absence of pink growth pigment, the lack of predominantly coccoid cellular morphology, and usually the inability to produce acid from xylose. The cellular fatty acid compositions of 29 group WO-1 strains were characterized by large amounts of C16:0 and C16:1w7c; smaller amounts of C18:1w7c, C14:0, C12:0, and 3-OH-C10:0; and trace to small amounts of C15:1w6 and C17:0 acids. The fatty acid profile of WO-1, compared with the profiles of other bacteria we have tested previously, was most similar to the profiles of two phenotypically different organisms, Comamonas terrigena (a nonoxidative, multipolar gram-negative rod) and Chromobacterium violaceum (a fermentative gram-negative rod). Ubiquinone-8 was the major quinone in the five WO-1 strains examined. Eighty-five percent of the WO-1 strains were isolated from human specimens. Thirty-three percent were from blood, and 10% were from cerebrospinal fluid.

Cell Movement↗
PubMed1991

The epidemiology of listeriosis in the United States--1986. Listeriosis Study Group.

To determine the morbidity and mortality due to listeriosis in the United States, the authors undertook an active surveillance project in 1986 to identify all cases in which Listeria monocytogenes was isolated from cultures of ordinarily sterile sites in a population of 34 million persons. The authors estimated that at least 1,700 cases of listeriosis and 450 deaths occurred in the United States in 1986; 27% of these cases occurred in pregnant women, with 22% of perinatal cases resulting in stillbirths or neonatal deaths. The risk of listeriosis in adults (0.5 per 100,000 population) was similar in all regions studied; the incidence of perinatal listeriosis was three times higher in Los Angeles County, California, than in the other areas (24.3/100,000 live births vs. 7.8/100,000 live births). Geographic variation may have resulted from underdiagnosis of perinatal listeriosis in five of the study areas. Multilocus electrophoretic enzyme typing was useful for elucidating the molecular epidemiology of L. monocytogenes; perinatal listeriosis was significantly associated with one group of related strains. Multilocus electrophoretic enzyme typing also identified three clusters representing possible common-source outbreaks. These findings document the substantial morbidity due to listeriosis in the United States; to the extent that sporadic listeriosis is foodborne, this morbidity could be reduced by appropriate preventive measures, particularly in persons known to be at increased risk of infection.

Adult↗