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Sharon L Abbott

Publications and source records attributed to Sharon L Abbott.

11 recordsLinked to original sources
PubMed2006

The genus Hafnia: from soup to nuts.

The genus Hafnia, a member of the family Enterobacteriaceae, consists of gram-negative bacteria that are occasionally implicated in both intestinal and extraintestinal infections in humans. Despite the fact that the genus currently contains only a single species (H. alvei), more extensive phylogenetic depth (two or more species) is apparent based upon DNA relatedness and 16S rRNA gene sequencing studies. Hafnia causes a variety of systemic infections, including septicemia and pneumonia; however, its role as a gastrointestinal pathogen is controversial. Many of the data supporting a role for hafniae as enteric pathogens were incorrectly attributed to this genus rather than to the actual pathogen, Escherichia albertii. There are numerous gaps in our understanding of this genus, including ecologic habitats and population genetics, disease-producing role in animals, phenetic and genetic methods useful in distinguishing genomospecies within the H. alvei complex, and bona fide pathogenicity factors.

Animals↗
PubMed2005

Phylogenetic relationships of the genus Kluyvera: transfer of Enterobacter intermedius Izard et al. 1980 to the genus Kluyvera as Kluyvera intermedia comb. nov. and reclassification of Kluyvera cochleae as a later synonym of K. intermedia.

In order to assess the relationship between the genus Kluyvera and other members of the family Enterobacteriaceae, the 16S rRNA genes of type strains of the recognized Kluyvera species, Kluyvera georgiana, Kluyvera cochleae, Kluyvera ascorbata and Kluyvera cryocrescens, were sequenced. A comparative phylogenetic analysis based on these 16S rRNA gene sequences and those available for strains belonging to several genera of the family Enterobacteriaceae showed that members of the genus Kluyvera form a cluster that contains all the known Kluyvera species. However, the type strain of Enterobacter intermedius (ATCC 33110T) was included within this cluster in a very close relationship with the type strain of K. cochleae (ATCC 51609T). In addition to the phylogenetic evidence, biochemical and DNA-DNA hybridization analyses of species within this cluster indicated that the type strain of E. intermedius is in fact a member of the genus Kluyvera and, within it, of the species Kluyvera cochleae. Therefore, following the current rules for bacterial nomenclature and classification, the transfer of E. intermedius to the genus Kluyvera as Kluyvera intermedia comb. nov. is proposed (type strain, ATCC 33110T=CIP 79.27T=LMG 2785T=CCUG 14183T). Biochemical analysis of four E. intermedius strains and one K. cochleae strain independent of the respective type strains further indicated that E. intermedius and K. cochleae represent the same species and are therefore heterotypic synonyms. Nomenclatural priority goes to the oldest legitimate epithet. Consequently, Kluyvera cochleae Muller et al. 1996 is a later synonym of Kluyvera intermedia (Izard et al. 1980) Pavan et al. 2005.

Bacterial Typing Techniques↗
PubMed2005

Description of Campylobacter curvus and C. curvus-like strains associated with sporadic episodes of bloody gastroenteritis and Brainerd's diarrhea.

Campylobacter curvus is a rarely encountered Campylobacter species in human, animal, and environmental samples. During the course of two investigations, one involving a search for possible bacterial agents causing bloody gastroenteritis and a second concerning a small outbreak of Brainerd's diarrhea in northern California, 20 strains of C. curvus or C. curvus-like organisms were isolated by a microfiltration technique and prolonged incubation. The results suggest that C. curvus may be an underappreciated Campylobacter that may be involved in sporadic and outbreak cases of bloody or chronic diarrhea in humans.

California↗
PubMed2005

Identification of two distinct hybridization groups in the genus Hafnia by 16S rRNA gene sequencing and phenotypic methods.

A collection of 52 strains belonging to the Hafnia alvei complex were subjected to molecular (16S rRNA gene sequencing) and biochemical analysis. Based upon 16S rRNA gene sequencing results, two genetic groups were identified which correspond with previously recognized DNA hybridization group 1 (ATCC 13337(T) and ATCC 29926; n = 23) and DNA hybridization group 2 (ATCC 29927; n = 29). Of 46 biochemical tests used to characterize hafniae, 19 reactions (41%) yielded variable results. Of these 19 tests, 6 were determined to have discriminatory value in the separation of DNA groups 1 and 2, with malonate utilization found to be the most differential test. Test results of malonate utilization alone correctly assigned 90% of Hafnia isolates to their correct DNA group.

Bacterial Typing Techniques↗
PubMed2004

Emergence of vancomycin-resistant enterococci in San Francisco Bay area hospitals during 1994 to 1998.

OBJECTIVE: To determine the magnitude of vancomycin-resistant enterococci (VRE) in three counties in the San Francisco Bay area. DESIGN: Active laboratory-based surveillance for VRE from January 1995 through December 1996 and a laboratory-based and hospital-based questionnaire survey for 1993 to 1994 and 1997 to 1998. SETTING: All 33 general acute care hospitals in three counties in the San Francisco Bay area. PARTICIPANTS: Laboratories and infection control professionals serving these hospitals, and staff of the California Emerging Infections Program. RESULTS: The number of hospitals reporting 1 or more patient clinical VRE isolates was 1 (3%) in 1993, 7 (21%) in 1994, 31 (94%) in 1995, and 33 (100%) in 1996 to 1998. The number of patient isolates increased from 1 in 1993 to 24 in 1994, 176 in 1995, 429 in 1996, 730 in 1997, and 864 in 1998. Most VRE isolates in 1995 and 1996 were from urine and were not associated with serious clinical disease. However, the number of isolates from blood increased from 9 (6% of total) in 1995 to 44 (12% of the total) in 1996, 90 (14%) in 1997, and 100 (13%) in 1998. CONCLUSIONS: Our data document the rapid emergence and increase of VRE in all hospitals in three counties in the San Francisco Bay area during 1994 to 1998. Infection control measures for VRE together with antibiotic utilization programs should be implemented to limit further spread.

Enterococcus↗
PubMed2003

Biochemical properties of a newly described Escherichia species, Escherichia albertii.

Five strains of a newly described Escherichia species, Escherichia albertii, were extensively characterized by conventional biochemical methods and by commercial identification panels. E. albertii is an indole-negative species that ferments D-mannitol but not D-xylose. Because these strains are not included in the databases of commercial systems at present, they were most often identified as Hafnia, Salmonella, Escherichia coli, or, on one system (MicroScan dried overnight panels), Yersinia ruckeri.

Bacterial Typing Techniques↗
PubMed2003

The genus Aeromonas: biochemical characteristics, atypical reactions, and phenotypic identification schemes.

A total of 193 strains representing 14 different Aeromonas genomospecies were evaluated for 63 phenotypic properties to create useful tables for the reference identification of mesophilic aeromonads. Only 9 of 62 biochemical tests (14%) yielded uniform results, and the fermentation of certain carbohydrates was found to be linked to specific species. A number of unusual or aberrant properties for the genus Aeromonas were also detected in the collection of 428 strains (193 in the phenotypic study, 235 in a retrospective review). These tests included susceptibility to the vibriostatic agent, fermentation of m-inositol and D-xylose, hydrolysis of urea, and the lack of cytochrome oxidase activity. Fermentation of melibiose was linked to raffinose fermentation in all Aeromonas species except A. jandaei. Keys are provided for clinical laboratories choosing to identify aeromonads to species level based upon initial Møeller decarboxylase and dihydrolase reactions. In addition, several new tests were identified that help to separate members of the A. caviae complex (A. caviae, A. media, and A. eucreonophila).

Aeromonas↗
PubMed2002

Phenotypic and genotypic properties of the genus Hafnia.

The present study characterised 73 Hafnia alvei isolates and five Escherichia isolates (originally identified as H. alvei) isolated from cases of diarrhoeal disease by the International Centre for Diarrhoeal Disease Research Branch (ICDDRB) in Bangladesh. Based upon the hydrolysis of arbutin and aesculin and the fermentation of salicin and D-arabinose, four distinct biotypes could be recognised among the 73 H. alvei isolates tested; biotype 1 (D-(-)-arabinose-positive only) accounted for 75% of all isolates analysed. Hydrolysis of aglycone compounds such as arbutin, salicin and aesculin appeared to be associated with expression of beta-glucosidase activity. ICDDRB isolates, when compared with type or reference strains of H. alvei, were shown not to belong to the genus Hafnia based upon resistance to Hafnia-specific bacteriophage 1672, possession of the phoE gene, expression of glutamate decarboxylase activity and significant 16S rDNA sequence divergence (approximately 8%) from the type strain, ATCC 13337T. True H. alvei strains, implicated in outbreaks of diarrhoeal disease in Canada, lacked the eaeA gene in contrast to ICDDRB isolates. Twenty-two H. alvei isolates were selected for further study. Based upon partial 16S rDNA sequencing, these 22 isolates fell into two genomic groups (genomospecies), identical to DNA groups previously established by DNA hybridisation studies. Markers such as motility, biotype, or enzymic or carbohydrate fermentation patterns did not correlate totally with DNA grouping, although malonate utilisation appeared to be the single best discriminatory phenotype. The results indicate that the genus Hafnia is heterogeneous and there do not appear to be any laboratory data available specifically linking these organisms to gastro-enteritis.

Adhesins, Bacterial↗
PubMedDate not supplied

A cluster of Escherichia coli O157: nonmotile infections associated with recreational exposure to lake water.

OBJECTIVES: To identify cases and determine risk factors for an outbreak of Escherichia coli (E. coli) O157: nonmotile (NM) infections in children attending a summer day care program in California. METHODS: The authors conducted a retrospective cohort study; the cohort comprised first and second graders who attended the day care program during the last week in August 1999. Shiga toxin testing and molecular subtyping using pulsed-field gel electrophoresis were performed on isolates. Lake water, lake bottom sediment samples, and waterfowl feces from the lake environs were cultured for E. coli O157. RESULTS: Three cases of Shiga toxin-producing E. coli O157: NM infections with matching pulsed-field gel electrophoresis patterns and four probable cases were found. Children who swallowed more than a mouthful of water had a higher attack rate than those who swallowed less than a mouthful or none at all (43% vs. 10%, relative risk = 4.43, 95% confidence interval 1.12, 17.50). CONCLUSIONS: E. coli O157: NM infections were associated with swallowing water from a freshwater lake. Potential sources of contamination include feces from humans, cattle, or deer. This outbreak illustrates the value in screening patients with diarrhea for E. coli O157, submitting isolates to public health laboratories, and using molecular techniques to identify related cases. Outbreaks associated with contaminated freshwater could be averted by prevention and early detection of contamination.

California↗
PubMedDate not supplied

Escherichia coli myonecrosis in alcoholic cirrhosis.

The risk of bacteremia in patients with cirrhosis increases with more advanced Child classification. Escherichia coli is the most frequently implicated organism in these bacteremic episodes. Unusually, E. coli can produce a bullous cellulitis or myonecrosis. Two previous cases of E. coli-associated myonecrosis in patients with cirrhosis have been reported. We describe a third case in a cirrhotic patient with E. coli-associated bilateral lower extremity gas gangrene and review the existing literature. In the three patients with cirrhosis and E. coli myonecrosis, no obvious gastrointestinal perforation was found as the source of bacteremia. Intestinal edema due to portal hypertension is thought to have facilitated mucosal microperforations and bacteremia. Awareness of this unusual presentation may facilitate earlier diagnosis.

Bacteremia↗