Predictability of Vibrio cholerae in Chesapeake Bay

ABSTRACT Vibrio cholerae is autochthonous to natural waters and can pose a health risk when it is consumed via untreated water or contaminated shellfish. The correlation between the occurrence of V. cholerae in Chesapeake Bay and environmental factors was investigated over a 3-year period. Water and plankton samples were collected monthly from five shore sampling sites in northern Chesapeake Bay (January 1998 to February 2000) and from research cruise stations on a north-south transect (summers of 1999 and 2000). Enrichment was used to detect culturable V. cholerae, and 21.1% (n = 427) of the samples were positive. As determined by serology tests, the isolates, did not belong to serogroup O1 or O139 associated with cholera epidemics. A direct fluorescent-antibody assay was used to detect V. cholerae O1, and 23.8% (n = 412) of the samples were positive. V. cholerae was more frequently detected during the warmer months and in northern Chesapeake Bay, where the salinity is lower. Statistical models successfully predicted the presence of V. cholerae as a function of water temperature and salinity. Temperatures above 19°C and salinities between 2 and 14 ppt yielded at least a fourfold increase in the number of detectable V. cholerae. The results suggest that salinity variation in Chesapeake Bay or other parameters associated with Susquehanna River inflow contribute to the variability in the occurrence of V. cholerae and that salinity is a useful indicator. Under scenarios of global climate change, increased climate variability, accompanied by higher stream flow rates and warmer temperatures, could favor conditions that increase the occurrence of V. cholerae in Chesapeake Bay.

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Non-O1/Non-O139 Vibrio cholerae Carrying Multiple Virulence Factors and V. cholerae O1 in the Chesapeake Bay, Maryland

Applied and Environmental Microbiology ◽

10.1128/aem.03540-14 ◽

2015 ◽

Vol 81 (6) ◽

pp. 1909-1918 ◽

Cited By ~ 41

Author(s):

Daniela Ceccarelli ◽

Arlene Chen ◽

Nur A. Hasan ◽

Shah M. Rashed ◽

Anwar Huq ◽

...

Keyword(s):

Chesapeake Bay ◽

Vibrio Cholerae ◽

Virulence Factors ◽

Fluorescent Antibody ◽

Secretion System ◽

Surveillance Program ◽

Toxin Gene ◽

Protease Gene ◽

Content Type ◽

Pathogenic Variants

ABSTRACTNon-O1/non-O139Vibrio choleraeinhabits estuarine and coastal waters globally, but its clinical significance has not been sufficiently investigated, despite the fact that it has been associated with septicemia and gastroenteritis. The emergence of virulent non-O1/non-O139V. choleraeis consistent with the recognition of new pathogenic variants worldwide. Oyster, sediment, and water samples were collected during a vibrio surveillance program carried out from 2009 to 2012 in the Chesapeake Bay, Maryland.V. choleraeO1 was detected by a direct fluorescent-antibody (DFA) assay but was not successfully cultured, whereas 395 isolates of non-O1/non-O139V. choleraewere confirmed by multiplex PCR and serology. Only a few of the non-O1/non-O139V. choleraeisolates were resistant to ampicillin and/or penicillin. Most of the isolates were sensitive to all antibiotics tested, and 77 to 90% carried the El Tor variant hemolysin genehlyAET, the actin cross-linking repeats in toxin genertxA, the hemagglutinin protease genehap, and the type 6 secretion system. About 19 to 21% of the isolates carried the neuraminidase-encoding genenanHand/or the heat-stable toxin (NAG-ST), and only 5% contained a type 3 secretion system. None of the non-O1/non-O139V. choleraeisolates containedVibriopathogenicity island-associated genes. However,ctxA,ace, orzotwas present in nine isolates. Fifty-five different genotypes showed up to 12 virulence factors, independent of the source of isolation, and represent the first report of both antibiotic susceptibility and virulence associated with non-O1/non-O139V. choleraefrom the Chesapeake Bay. Since these results confirm the presence of potentially pathogenic non-O1/non-O139V. cholerae, monitoring for totalV. cholerae, regardless of serotype, should be done within the context of public health.

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Seasonal Cholera Caused by Vibrio cholerae Serogroups O1 and O139 in the Coastal Aquatic Environment of Bangladesh

Applied and Environmental Microbiology ◽

10.1128/aem.00066-06 ◽

2006 ◽

Vol 72 (6) ◽

pp. 4096-4104 ◽

Cited By ~ 72

Author(s):

Munirul Alam ◽

Nur A. Hasan ◽

Abdus Sadique ◽

N. A. Bhuiyan ◽

Kabir U. Ahmed ◽

...

Keyword(s):

Vibrio Cholerae ◽

Aquatic Environment ◽

Ecological Study ◽

Enrichment Culture ◽

Fluorescent Antibody ◽

Blot Hybridization ◽

Culture Methods ◽

Lack Of Information ◽

Direct Fluorescent Antibody ◽

El Tor

ABSTRACT Since Vibrio cholerae O139 first appeared in 1992, both O1 El Tor and O139 have been recognized as the epidemic serogroups, although their geographic distribution, endemicity, and reservoir are not fully understood. To address this lack of information, a study of the epidemiology and ecology of V. cholerae O1 and O139 was carried out in two coastal areas, Bakerganj and Mathbaria, Bangladesh, where cholera occurs seasonally. The results of a biweekly clinical study (January 2004 to May 2005), employing culture methods, and of an ecological study (monthly in Bakerganj and biweekly in Mathbaria from March 2004 to May 2005), employing direct and enrichment culture, colony blot hybridization, and direct fluorescent-antibody methods, showed that cholera is endemic in both Bakerganj and Mathbaria and that V. cholerae O1, O139, and non-O1/non-O139 are autochthonous to the aquatic environment. Although V. cholerae O1 and O139 were isolated from both areas, most noteworthy was the isolation of V. cholerae O139 in March, July, and September 2004 in Mathbaria, where seasonal cholera was clinically linked only to V. cholerae O1. In Mathbaria, V. cholerae O139 emerged as the sole cause of a significant outbreak of cholera in March 2005. V. cholerae O1 reemerged clinically in April 2005 and established dominance over V. cholerae O139, continuing to cause cholera in Mathbaria. In conclusion, the epidemic potential and coastal aquatic reservoir for V. cholerae O139 have been demonstrated. Based on the results of this study, the coastal ecosystem of the Bay of Bengal is concluded to be a significant reservoir for the epidemic serogroups of V. cholerae.

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Toxigenic Vibrio cholerae in the Aquatic Environment of Mathbaria, Bangladesh

Applied and Environmental Microbiology ◽

10.1128/aem.72.4.2849-2855.2006 ◽

2006 ◽

Vol 72 (4) ◽

pp. 2849-2855 ◽

Cited By ~ 97

Author(s):

Munirul Alam ◽

Marzia Sultana ◽

G. Balakrish Nair ◽

R. Bradley Sack ◽

David A. Sack ◽

...

Keyword(s):

Vibrio Cholerae ◽

Aquatic Environment ◽

Fluorescent Antibody ◽

Culture Methods ◽

Viable But Nonculturable ◽

Large Numbers ◽

Direct Fluorescent Antibody ◽

Nonculturable Cells ◽

Seasonal Epidemics

ABSTRACT Toxigenic Vibrio cholerae, rarely isolated from the aquatic environment between cholera epidemics, can be detected in what is now understood to be a dormant stage, i.e., viable but nonculturable when standard bacteriological methods are used. In the research reported here, biofilms have proved to be a source of culturable V. cholerae, even in nonepidemic periods. Biweekly environmental surveillance for V. cholerae was carried out in Mathbaria, an area of cholera endemicity adjacent to the Bay of Bengal, with the focus on V. cholerae O1 and O139 Bengal. A total of 297 samples of water, phytoplankton, and zooplankton were collected between March and December 2004, yielding eight V. cholerae O1 and four O139 Bengal isolates. A combination of culture methods, multiplex-PCR, and direct fluorescent antibody (DFA) counting revealed the Mathbaria aquatic environment to be a reservoir for V. cholerae O1 and O139 Bengal. DFA results showed significant clumping of the bacteria during the interepidemic period for cholera, and the fluorescent micrographs revealed large numbers of V. cholerae O1 in thin films of exopolysaccharides (biofilm). A similar clumping of V. cholerae O1 was also observed in samples collected from Matlab, Bangladesh, where cholera also is endemic. Thus, the results of the study provided in situ evidence for V. cholerae O1 and O139 in the aquatic environment, predominantly as viable but nonculturable cells and culturable cells in biofilm consortia. The biofilm community is concluded to be an additional reservoir of cholera bacteria in the aquatic environment between seasonal epidemics of cholera in Bangladesh.

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Comparison of direct, Rapid Immunohistochemical Test Performance with Direct Fluorescent Antibody Test for rabies diagnosis in Ethiopia

Open Journal of Biochemistry ◽

10.15764/bioc.2014.01006 ◽

2014 ◽

Vol 1 (1) ◽

pp. 49-55 ◽

Cited By ~ 3

Author(s):

Abraham Ali ◽

◽

Dessalegn Sifer ◽

Garoma Getahun ◽

Mesfin Hussein

Keyword(s):

Test Performance ◽

Fluorescent Antibody ◽

Antibody Test ◽

Direct Fluorescent Antibody ◽

Rabies Diagnosis

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A Most Probable Number Method for the Enumeration of Legionella Bacteria in Water

Water Science & Technology ◽

10.2166/wst.1991.0046 ◽

1991 ◽

Vol 24 (2) ◽

pp. 143-147 ◽

Cited By ~ 6

Author(s):

N. A. Grabow ◽

R. Kfir ◽

W. O. K. Grabow

Keyword(s):

Water Samples ◽

Membrane Filtration ◽

Quantitative Method ◽

Fluorescent Antibody ◽

Most Probable Number ◽

Probable Number ◽

Comparative Tests ◽

Antibody Staining ◽

Direct Fluorescent Antibody ◽

Yeast Extract Agar

A new quantitative method for the enumeration of Legionella bacteria in water is described. Appropriate tenfold serial dilutions of water samples concentrated by membrane filtration are plated in triplicate on buffered charcoal yeast extract agar. After incubation for 3 days representative smears from individual plates are tested for the presence of Legionella by direct fluorescent antibody staining. The number of positive plates in each dilution is used to calculate the Legionella count by means of conventional most probable number statistics. In comparative tests on a variety of water samples this method yielded significantly higher counts than previously used procedures.

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