Neoadjuvant chemoradiotherapy for esophageal cancer using weekly Paclitaxel and Carboplatin plus infusional 5-Fluorouracil.

PURPOSE: To evaluate neoadjuvant therapy with weekly paclitaxel/carboplatin plus 5-fluorouracil (5-FU) with conformal radiotherapy in a phase II trial in resectable esophageal carcinoma. METHODS: Twenty-four patients with T2-4N0-1M0-1a esophageal carcinoma were treated with paclitaxel 45 mg/m(2) intravenously over 1 hour and carboplatin at an area under the concentration-time curve (AUC) of 2 intravenously over 30 minutes on days 1, 8, 15, 22, and 29. 5-Fluorouracil 225 mg/m(2) was delivered as a continuous infusion on days 1-33. Concurrent conformal radiation was delivered to a dose of 45 Gy. Responders underwent surgical resection within 8 weeks of completing chemoradiotherapy. Kaplan-Meier survival analysis and log-rank test of survival dependent on pathologic response were performed. RESULTS: Progressive disease was discovered at surgery in three patients. Of the remaining 21 patients, pathologic complete response (pCR) was demonstrated in 12 (pCR rate of 57%) and partial response (PR) occurred in 9, including 4 with near complete response. Median follow-up in all patients was 23 months. Overall survival among all 24 patients was 48% at 3 years, with a median of 31 months. Disease-free survival was 57% at 3 years, with a median of 38 months. Differences in survival time based on pCR vs. PR showed a trend favoring pCR for disease-free survival (P = .12) but not overall survival (P > .20). Grade 3/4 toxicities included esophagitis in 33% of patients, hypotension in 29%, stomatitis in 25%, neutropenia in 13%, and anemia in 8%. CONCLUSION: This study demonstrates the activity of neoadjuvant paclitaxel, carboplatin, 5-FU, and conformal radiotherapy in the treatment of localized esophageal cancer. Evaluation with a larger number of patients and longer follow-up will be required to definitively assess the long-term efficacy of this regimen.

Sensitivity of Vibrio species in phosphate-buffered saline and in oysters to high-pressure processing.

Multiple strains of Vibrio vulnificus, Vibrio parahaemolyticus, and Vibrio cholerae non-O1 were tested in phosphate-buffered saline for their sensitivity to high-pressure processing (HPP). Variability in sensitivity among strains was observed for all species; this variability decreased at higher pressures. V. vulnificus was the species that was most sensitive to treatment at 200 MPa (decimal reduction time [D] = 26 s), and V. cholerae was the species that was most resistant to treatment at 200 MPa (D = 149 s). The O3:K6 serotype of V. parahaemolyticus was more resistant to pressure than other serotypes of V. parahaemolyticus were. The results of studies involving V. vulnificus naturally occurring in oysters revealed that a pressure treatment of 250 MPa for 120 s achieved a > 5-log reduction in the levels of this bacterium. V. parahaemolyticus serotype O3:K6 in oysters required a pressure of 300 MPa for 180 s for a comparable 5-log reduction. When properly applied, HPP can be effective in improving the safety of shellfish with respect to Vibrio spp.

Seasonal abundance of total and pathogenic Vibrio parahaemolyticus in Alabama oysters.

Recent Vibrio parahaemolyticus outbreaks associated with consumption of raw shellfish in the United States focused attention on the occurrence of this organism in shellfish. From March 1999 through September 2000, paired oyster samples were collected biweekly from two shellfish-growing areas in Mobile Bay, Ala. The presence and densities of V. parahaemolyticus were determined by using DNA probes targeting the thermolabile hemolysin (tlh) and thermostable direct hemolysin (tdh) genes for confirmation of total and pathogenic V. parahaemolyticus, respectively. V. parahaemolyticus was detected in all samples with densities ranging from <10 to 12,000 g(-1). Higher V. parahaemolyticus densities were associated with higher water temperatures. Pathogenic strains were detected in 34 (21.8%) of 156 samples by direct plating or enrichment. Forty-six of 6,018 and 31 of 6,992 V. parahaemolyticus isolates from enrichments and direct plates, respectively, hybridized with the tdh probe. There was an apparent inverse relationship between water temperature and the prevalence of pathogenic strains. Pathogenic strains were of diverse serotypes, and 97% produced urease and possessed a tdh-related hemolysin (trh) gene. The O3:K6 serotype associated with pandemic spread and recent outbreaks in the United States was not detected. The efficient screening of numerous isolates by colony lift and DNA probe procedures may account for the higher prevalence of samples with tdh(+) V. parahaemolyticus than previously reported.

Density of total and pathogenic (tdh+) Vibrio parahaemolyticus in Atlantic and Gulf coast molluscan shellfish at harvest.

The densities of total and pathogenic Vibrio parahaemolyticus in 671 samples of molluscan shellfish harvested in 1999 and 2000 from 14 sites in seven Gulf and Atlantic coast states were determined at 2-week intervals over a period of 12 to 16 months in each state. Changes in V. parahaemolyticus densities in shellfish between harvest and sample analysis were minimized with time and temperature controls. Densities were measured by direct plating techniques, and gene probes were used for identification. Total and pathogenic V. parahaemolyticus organisms were identified with probes for the thermolabile direct hemolysin (tlh) gene and the thermostable direct hemolysin (tdh) gene, respectively. An enrichment procedure involving 25 g of shellfish was also used for the recovery of pathogenic V. parahaemolyticus. The densities of V. parahaemolyticus in shellfish from all harvest sites were positively correlated with water temperature. Shellfish from the Gulf Coast typically had higher densities of V. parahaemolyticus than did shellfish harvested from the North Atlantic or mid-Atlantic coast. Vibrio parahaemolyticus counts exceeded 1,000 CFU/g for only 5% of all samples. Pathogenic (tdh+) V. parahaemolyticus was detected in approximately 6% of all samples by both procedures, and 61.5% of populations in the positive samples from the direct plating procedure were at the lower limit of detection (10 CFU/g). The frequency of detection of pathogenic V. parahaemolyticus was significantly related to water temperature and to the density of total V. parahaemolyticus. The failure to detect pathogenic V. parahaemolyticus in shellfish more frequently was attributed to the low numbers and uneven distribution of the organism.

Vibrio vulnificus and Vibrio parahaemolyticus in U.S. retail shell oysters: a national survey from June 1998 to July 1999.

From June 1998 to July 1999, 370 lots of oysters in the shell were sampled at 275 different establishments (71%, restaurants or oyster bars; 27%, retail seafood markets: and 2%, wholesale seafood markets) in coastal and inland markets throughout the United States. The oysters were harvested from the Gulf (49%). Pacific (14%), Mid-Atlantic (18%), and North Atlantic (11%) Coasts of the United States and from Canada (8%). Densities of Vibrio vulnificus and Vibrio parahaemolyticus were determined using a modification of the most probable number (MPN) techniques described in the Food and Drug Administration's Bacteriological Analytical Manual. DNA probes and enzyme immunoassay were used to identify suspect isolates and to determine the presence of the thermostable direct hemolysin gene associated with pathogenicity of V. parahaemolyticus. Densities of both V. vulnifcus and V. parahaemolyticus in market oysters from all harvest regions followed a seasonal distribution, with highest densities in the summer. Highest densities of both organisms were observed in oysters harvested from the Gulf Coast, where densities often exceeded 10,000 MPN/g. The majority (78%) of lots harvested in the North Atlantic, Pacific, and Canadian Coasts had V. vulnificus densities below the detectable level of 0.2 MPN/g; none exceeded 100 MPN/g. V. parahaemolyticus densities were greater than those of V. vulnificus in lots from these same areas, with some lots exceeding 1,000 MPN/g for V. parahaemolyticus. Some lots from the Mid-Atlantic states exceeded 10,000 MPN/g for both V. vulnificus and V. parahaemolyicus. Overall, there was a significant correlation between V. vulificus and V. parahaemolyticus densities (r = 0.72, n = 202, P < 0.0001), but neither density correlated with salinity. Storage time significantly affected the V. vulnificus (10% decrease per day) and V. parahaemolyticus (7% decrease per day) densities in market oysters. The thermostable direct hemolysin gene associated with V parahaemolyticus virulence was detected in 9 of 3,429 (0.3%) V. parahaemolyticus cultures and in 8 of 198 (4.0%) lots of oysters. These data can be used to estimate the exposure of raw oyster consumers to V. vulnificus and V. parahaemolyticus.

Refrigeration of Oyster Shellstock: Conditions Which Minimize the Outgrowth of Vibrio vulnificus.

The multiplication of Vibrio vulnificus in summer harvest oyster shellstock held without refrigeration was followed over a 14 h postharvest period. Mean (n = 7) increases were 0,75, 1.30, 1.74, and 1.94 log units at 3.5 h, 7 h, 10.5 h, and 14 h postharvest, respectively. Aerobic plate counts (spread plates on plate count agar [PCA] containing 1% NaCl, 25°C) but not standard plate counts (pour plates, PCA, 35°C) showed a similar trend in increase. Reducing the time oyster shellstock remains outside refrigeration can decrease consumer exposure to high numbers of V. vulnificus , but shellstock must be cooled immediately after harvest to eliminate postharvest growth of this bacterium.

Cold Storage and Mild Heat Treatment as Processing Aids to Reduce the Numbers of Vibrio vulnificus in Raw Oysters.

Pure cultures of Vibrio vulnificus held at temperatures of 4 and 0°C underwent a time-dependent decrease in number of recoverable cells. A similar pattern of decreasing numbers was observed with naturally occurring V. vulnificus in cold stored shellstock oysters and shucked oyster meats. The time required for the bacterium to reach undetectable levels (MPN <3/g) may exceed the usual storage life of 14 d for shucked oyster meats and 21 d for shellstock oysters. Freezing and storage of pure cultures of V. vulnificus at -20°C reduced the number of culturable cells more quickly than did holding the cultures at 0°C. However, the organism was cultured from oysters frozen at -20°C for 12 weeks. While cold storage reduced the numbers of V. vulnificus in oysters, such treatment cannot be relied upon to eliminate the organism. Exposure to temperatures above 45°C causes death of V. vulnificus . Decimal reduction times at 47°C for 52 strains averaged 78 s (SD ± 30 s), and D50 values for 18 of the hardiest strains averaged 39.8 s (SD ± 12.2 s). Heating oysters for 10 min in water at 50°C proved adequate to reduce V. vulnificus to a nondetectable level. This treatment does not impart a noticeable cooked appearance or taste to the oysters and may be employed as a strategy to improve the safety of raw oysters.

Vibrio vulnificus and Indicator Bacteria in Shellstock and Commercially Processed Oysters from the Gulf Coast.

Fifty-one interstate shipments of shellstock oysters were sampled at processing plants and examined bacteriologically for Vibrio vulnificus , fecal coliforms, Escherichia coli , and standard plate count. The occurrence of V. vulnificus in the oysters was seasonal with low numbers during the winter and levels frequently exceeding 110,000/g during the summer. The numbers of V. vulnificus correlated (p < 0.01) with fecal coliform levels in the oysters and with water temperatures in the harvest areas. Normal commercial processing did not significantly (p > 0.05) reduce the levels of V. vulnificus or indicator bacteria in the oyster meats. However, storage of the processed meats in containers packed on ice usually produced a one-log and two-log unit reduction in numbers of V. vulnificus after 3 and 7 d, respectively.

Indicator Bacteria and Vibrionaceae Multiplication in Post-Harvest Shellstock Oysters.

Changes in the levels of indicator bacteria and Vibrionaceae were monitored in post-harvest shellstock oysters during commercial transport and during storage at temperatures of 10°C, 22°C, and 30°C. Aerobic plate counts, fecal coliforms including Escherichia coli , and Vibrionaceae including Vibrio cholerae , V. parahaemolyticus , V. vulnificus , and Aeromonas hydrophila increased in numbers in shellstock oysters during transport and storage at 22°C and 30°C. Increases in the levels of indicator bacteria were generally accompanied by increases in Vibrionaceae , but sometimes the Vibrionaceae multiplied in the absence of fecal coliform multiplication. Storage of oysters at 10°C prevented multiplication of vibrios and fecal coliforms, but not Aeromonas hydrophila .

Relaying to Decrease the Concentration of Oyster-Associated Pathogens.

Oysters experimentally contaminated with indicator bacteria, Salmonella and poliovirus were used in relaying studies designed to measure microbial elimination under a variety of environmental conditions. Two factors, level of microorganism in the oyster and temperature of the water, were important in determining the length of time necessary to purge the contaminating organisms. Oysters under physiological stress cleansed at a slower rate than did healthy oysters. Based on the expected level of pathogen contamination in naturally polluted oysters, healthy relaid oysters were capable of cleansing in a 7-d period provided the temperature was above 10°C. These results were verified by following the elimination of indicator bacteria and poliovirus in commercially relaid oysters. Fecal indicator bacteria and enteric pathogenic bacteria were eliminated at similar rates but fecal coliform levels did not correlate with virus elimination. Relaying waters may contain some indicator bacteria and this study suggested that fecal coliforms may not be useful as end-point indicators for this method of oyster purification.