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Category: Clinical Microbiology
Vibrio and Related Organisms * , Page 1 of 2
< Previous page | Next page > /docserver/preview/fulltext/10.1128/9781555816728/9781555814632_Chap39-1.gif /docserver/preview/fulltext/10.1128/9781555816728/9781555814632_Chap39-2.gifAbstract:
This chapter focuses on the various Vibrionaceae species that cause disease in humans. Vibrio is the type genus for the family, and Vibrio cholerae, the causative agent of pandemic cholera, is the type species. The genera covered in the chapter are primarily isolated from marine environments. Recent studies have shown that in mixed populations of nonculturable and culturable cells of V. cholerae, the latter appear to be the main contributors to human infections. The majority of persons ingesting toxigenic V. cholerae O1 have asymptomatic infections. Most of the advantages of PCR-based assays over culture methods apply to vibrios and include the ability to freeze stools for epidemiological studies for delayed testing. Molecular identification of vibrios is commonplace in surveys and in research studies. However, it is not commonly employed in clinical laboratories for routine identification because vibrios are relatively rare pathogens in noncoastal areas or regions where cholera is not endemic. The clinical significance of Vibrio strains in other specimens, particularly stool, may be more difficult to determine and requires prompt consultation with the attending physician to better understand the clinical context. Vibrionaceae isolates should also be submitted to public health laboratories, as they are monitored under the CDC’s International Emerging Infections Program and Vibrio Surveillance System; they may also be needed for confirmation and toxin testing. Misidentification of Vibrio species and their relatives can be a problem in the literature unless investigators used methods that are very sensitive in differentiating all of the species in the family Vibrionaceae.
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Properties of the genus Vibrio and its relatives: differentiation from other organisms that are phenotypically similar a
a These are general properties of the genera and/or family, but there are exceptions. The properties of Vibrio apply to the species that occur in human clinical specimens and may not apply to all nonclinical species. Symbols: +, most strains positive; –, most strains negative.
b Strains of Grimontia hollisae typically grow poorly or not at all on TCBS agar; those that grow may have a reduced plating efficiency.
c O/129, 2, 4-diamino-6, 7-diisopropylpteridine phosphate (commercially available, 150-µg disks).
d Resistance to O/129 has become common in Vibrio cholerae strains isolated from India and Bangladesh; V. cholerae O139 strains are resistant.
Properties of the genus Vibrio and its relatives: differentiation from other organisms that are phenotypically similar a
a These are general properties of the genera and/or family, but there are exceptions. The properties of Vibrio apply to the species that occur in human clinical specimens and may not apply to all nonclinical species. Symbols: +, most strains positive; –, most strains negative.
b Strains of Grimontia hollisae typically grow poorly or not at all on TCBS agar; those that grow may have a reduced plating efficiency.
c O/129, 2, 4-diamino-6, 7-diisopropylpteridine phosphate (commercially available, 150-µg disks).
d Resistance to O/129 has become common in Vibrio cholerae strains isolated from India and Bangladesh; V. cholerae O139 strains are resistant.
Biochemical test results and other properties of the 12 Vibrionaceae species that occur in human clinical specimens a
a Abbreviations: HIB, heart infusion broth; VP, Voges-Proskauer; ONPG, o-nitrophenyl-β-d-galactopyranoside; NaCl, sodium chloride; NA, not available.
b Percentage of strains positive after 48 h of incubation at 36°C unless otherwise indicated. Most positive reactions occur within 24 h.
c 1% NaCl added to all media except salt tolerance tests.
d This organism is oxidase negative and does not reduce nitrate to nitrite.
e Biogroup 1 strains.
f Zone of inhibition present (disk content, 150 µg). Data for Plesiomonas are from the Microbial Diseases Laboratory.
Biochemical test results and other properties of the 12 Vibrionaceae species that occur in human clinical specimens a
a Abbreviations: HIB, heart infusion broth; VP, Voges-Proskauer; ONPG, o-nitrophenyl-β-d-galactopyranoside; NaCl, sodium chloride; NA, not available.
b Percentage of strains positive after 48 h of incubation at 36°C unless otherwise indicated. Most positive reactions occur within 24 h.
c 1% NaCl added to all media except salt tolerance tests.
d This organism is oxidase negative and does not reduce nitrate to nitrite.
e Biogroup 1 strains.
f Zone of inhibition present (disk content, 150 µg). Data for Plesiomonas are from the Microbial Diseases Laboratory.