Although autochthonous vibrio densities are known to be influenced by water temperature and salinity, little is understood about other environmental factors associated with their abundance and distribution. Densities of culturable Vibrio vulnificus containing vvh (V. vulnificus hemolysin gene) and V. parahaemolyticus containing tlh (thermolabile hemolysin gene, ubiquitous in V. parahaemolyticus), tdh (thermostable direct hemolysin gene, V. parahaemolyticus pathogenicity factor), and trh (tdh-related hemolysin gene, V. parahaemolyticus pathogenicity factor) were measured in coastal waters of Mississippi and Alabama. Over a 19-month sampling period, vibrio densities in water, oysters, and sediment varied significantly with sea surface temperature (SST). On average, tdh-to-tlh ratios were significantly higher than trh-to-tlh ratios in water and oysters but not in sediment. Although tlh densities were lower than vvh densities in water and in oysters, the opposite was true in sediment. Regression analysis indicated that SST had a significant association with vvh and tlh densities in water and oysters, while salinity was significantly related to vibrio densities in the water column. Chlorophyll a levels in the water were correlated significantly with vvh in sediment and oysters and with pathogenic V. parahaemolyticus (tdh and trh) in the water column. Furthermore, turbidity was a significant predictor of V. parahaemolyticus density in all sample types (water, oyster, and sediment), and its role in predicting the risk of V. parahaemolyticus illness may be more important than previously realized. This study identified (i) culturable vibrios in winter sediment samples, (ii) niche-based differences in the abundance of vibrios, and (iii) predictive signatures resulting from correlations between environmental parameters and vibrio densities.Vibrio spp. occur naturally in estuarine and marine environments, and two species of this genus, V. vulnificus and V. parahaemolyticus, are responsible for the majority of reported vibrio illnesses in the United States (2). V. vulnificus infections are most commonly associated with the Gulf of Mexico, either via consumption of raw oysters harvested from these waters or wound infections following exposure to seawater. On average, about 50 cases of V. vulnificus septicemia are reported in the United States each year, with a case fatality rate of approximately 50% (31), the highest of any food-borne pathogen. In contrast, V. parahaemolyticus is the most common cause of seafood-associated bacterial gastroenteritis in the United States, with an estimated annual rate of 4,500 cases per year according to the Centers for Disease Control and Prevention. V. parahaemolyticus also causes wound infections, though these are less frequent and less severe compared to those caused by V. vulnificus (5). Primary septicemia can occur following V. parahaemolyticus infection, but it is relatively rare for this pathogen. In the United States, V. parahaemolyticus illness most often results from consumption of r...

Vibrio parahaemolyticus is indigenous to coastal environments and a frequent cause of seafood-borne gastroenteritis in the United States, primarily due to raw-oyster consumption. Previous seasonal-cycle studies of V. parahaemolyticus have identified water temperature as the strongest environmental predictor. Salinity has also been identified, although it is evident that its effect on annual variation is not as pronounced. The effects of other environmental factors, both with respect to the seasonal cycle and intraseasonal variation, are uncertain. This study investigated intraseasonal variations of densities of total and pathogenic V. parahaemolyticus organisms in oysters and overlying waters during the summer of 2004 at two sites in the northern Gulf of Mexico. Regression analyses indicated significant associations (P < 0.001) between total V. parahaemolyticus densities and salinity, as well as turbidity in water and in oysters at the Mississippi site but not at the Alabama site. Pathogenic V. parahaemolyticus organisms in Mississippi oyster and water samples were detected in 56% (9 out of 16) and 78% (43 out of 55) of samples, respectively. In contrast, 44% (7 out of 16) of oyster samples and 30% (14 out of 47) of water samples from Alabama were positive. At both sites, there was greater sample-to-sample variability in pathogenic V. parahaemolyticus densities than in total V. parahaemolyticus densities. These data suggest that, although total V. parahaemolyticus densities may be very informative, there is greater uncertainty when total V. parahaemolyticus densities are used to predict the risk of infection by pathogenic V. parahaemolyticus than previously recognized.Vibrio parahaemolyticus is the leading cause of Vibrio-associated gastroenteritis in the United States (15,19,20,32) and has been isolated from oysters, blue crabs, finfish, and planktonic copepods (6,7,18,22). Vibrio infections are most common in individuals living in states bordering the Gulf of Mexico (23) and are usually associated with the consumption of raw shellfish, primarily oysters (9, 20). Recent outbreaks (4,5,10,14) raised the awareness of public health officials concerning shellfish throughout coastal states and prompted the Interstate Shellfish Sanitation Conference to develop an Interim Control Plan for regulating shellfish harvest areas based on V. parahaemolyticus densities in shellfish (31). The Interim Control Plan employs a colony lift technique using DNA probes that target the species-specific thermolabile hemolysin (tlh) gene and the thermostable direct hemolysin (tdh) gene associated with pathogenic V. parahaemolyticus strains (32). A similar DNA probe colony hybridization method has been developed to target the tdh-related hemolysin gene (trh), which is also associated with pathogenic strains of V. parahaemolyticus (27). While these colony lift techniques make it possible to investigate the distribution of pathogenic V. parahaemolyticus strains directly, they have a relatively high limit of detection (LOD). Thus, the colony...

In the bacteriological laboratories of Brown University and the Connecticut State Department of Health, Bureau of Laboratories, we have been engaged in a systematic study of the biochemical and serological relationships of the coliform and related bacteria since April 1937. During this time over 12,000 normal and aberrant coliform cultures have been isolated. The IMViC reactions and in addition cellobiose fermentation were determined for all these cultures. A wide variety of biochemical types were encountered ranging from those positive in all five tests to a few weakly positive in only one of the IMViC tests. The ability of more than 3,500 of these cultures to ferment glucose, lactose, sucrose, salicin, maltose and mannitol was determined. Normal coliform cultures negative in sucrose or salicin or both were commonly found. Strains failing to ferment maltose were not anticipated but several were isolated from widely different sources. Mannitol fermentation appeared to be a constant characteristic of normal coliforms but among the last 500 isolations two, otherwise normal, mannitol-negative strains were obtained.Coliform cultures fermenting lactose slowly or not at all, but normal in other respects, were frequently encountered. We have obtained from both rapid and slow lactose-fermenting coliforms variants which were anaerogenic in lactose only or in all carbohydrates. Some of these variants have remained constant for 2 years, one for more than 3 years. In addition motile and nonmotile, indolepositive cultures were found which produced no gas from carbohydrates when originally isolated. Many such cultures would be classed as Eberthella or Shigella, particularly when the fermentation of lactose, sucrose or salicin was slow or absent. After varying periods of laboratory cultivation many of these strains produced gas. Cultures that appeared to be non-gas-forming but which could not be identified as known Eberthella or Shigella have been included in the paracolon group since they could be anaerogenic variants of coliforms.These exceptions and others are a serious handicap to the practical bacteriologist because strains not infrequently defy classification in any of the recognized sections of the coliform group. The tendency to disregard such exceptions for the most part is justifiable but occasionally this might be a mistake. Stuart, Mickle and Borman (1940) proposed the term "aberrant" coliforms for cultures not fermenting lactose, producing acid only, or requiring more than 48 hours for the production of 20 per cent gas when the unusual fermenting characteristics of such strains are relatively stable. Aberrant coliforms are frequently isolated from such sources as water with an excellent sanitary survey, soils from rigidly 101 on August 5, 2020 by guest http://jb.asm.org/ Downloaded from 140 paracolon Aerobacter cultures were actively motile.Paracolon Aerobacter can be separated into 2 divisions on the basis of their IMViC reactions. Division 1 consists of 48 strains which gave a strong Voges-Proskauer reaction, gr...