The prevalence of bacterial pathogens and rotavirus in 2,908 patients with diarrhea who were admitted to San Lazaro Hospital in Manila in 1983 and 1984 was determined. One or more enteric pathogens were isolated or detected in samples from 1,698 (58.4%) patients. Isolation rates for the various enteropathogens were as follows: rotavirus, 30.6%; Shigella spp., 11.6%; Salmonella spp., 9.2%; enterotoxigenic Escherichia coli (1983 only), 7.8%; Vibrio cholerae biotype eltor, 3.8%; non-Ol V. cholerae, 2.8%; Vibrio parahaemolyticus, 1.7%; other Vibrio spp., 1.1%; Campylobacter jejuni, 3.0%; Aeromonas hydrophila, 1.3%; and Plesiomonas shigeloides 1.1%. Giardia lamblia and Entamoeba histolytica were detected in 0.6 and 0.1%, respectively, of stool samples examined. Determination of the etiologic role of isolates was complicated by one or more of the following factors: (i) isolation of multiple enteric pathogens (302 cases); (il) isolation of Salmonella spp., enterotoxigenic E. coli, and C. jejuni from a similar proportion of asymptomatic control patients and patients with diarrhea; and (iii) isolation of a high proportion of certain pathogens (especially Salmonella spp.) only from enrichment broth, suggesting infection with a small number of organisms. Isolation of V. cholerae eltor was seasonal, with the majority of cases occurring in the rainy months. In addition, the number of patients with diarrhea increased with the onset of the monsoon rains and peaked during the months of maximum rainfall. Rotavirus infection occurred in both children and adults throughout the year and was the most frequently identified cause of diarrhea in children under 5 years of age. Shigella spp. were the most common agents of diarrhea in adults.

During 1984, the recovery of enteric pathogens from patients with acute diarrhea was enhanced by the use of both rectal swab and stool specimens. With 513 patients for whom both methods were used, the overall recovery rate was increased a minimum of about 10%. Almost 50% of the organisms recovered were detected by only one method. For maximum recovery of diarrheal agents, the use of both methods is recommended when possible.

101 patients with a clinical suspicion of typhoid or paratyphoid (enteric) fever admitted to San Lazaro Hospital, Manila, Philippines, were studied by bacteriological culture of blood, rectal swab, urine and duodenal string capsule; 35 also had bacteriological culture of bone marrow aspirate. 44 of the patients were culture-confirmed as having enteric fever; the remainder were classified as non-enteric fever cases. Analysis of the pretreatment Widal agglutination titres of all patients revealed that using as a diagnostic criterion an antibody titre of greater than or equal to 1:80 to the O antigen of Salmonella typhi yielded a test specificity of 100%, although the corresponding sensitivity was only 64%. The sensitivity of the test could be increased to 80% by using different cut-off values for titres to flagellar antigens, but this concomitantly decreased the test specificity from 100 to 82%. The data indicate that a single pretreatment Widal test in suspected enteric fever cases is of definite diagnostic value, but that the results must be interpreted with caution and foreknowledge of the test's shortcomings and limitations.

A total of 640 blood specimens from patients in an area endemic for enteric fever were cultured in parallel in tryptic soy broth with and without sodium polyanethanol sulfonate (SPS). A total of 95 specimens were positive for Salmonella spp., 54 for Salmonella typhi, and 41 for Salmonella paratyphi A in one or both bottles of a set. Significantly higher rates of recovery were obtained from the SPS-containing medium (P < 0.01) upon subculturing blindly at 24 h and 3 days of incubation. Subcultures performed at 7, 14, and 21 days also yielded a greater number of positive cultures with SPS than without it, although the differences between the two media were not significant (P > 0.05). Neither of the media yielded 100% of the positive cultures. Moreover, even if the results of the two media were combined, 34 and l9o of the isolates would have been missed if the specimens had not been incubated to 14 and 21 days, respectively. The data indicate that SPS aids in early recovery of S. typhi and S. paratyphi A from blood cultures, and additionally, that under the conditions used in the study, incubation beyond a 1-week period is required for efficient isolation of these organisms from blood.

The Y1 adrenal cell tissue culture assay was used to detect heat-labile enterotoxin-like activity in the stools of 14 of 74 patients with diarrhea. A positive effect of the stool on the adrenal cells was heat-labile and neutralized by cholera antitoxin. Enterotoxin-like activity was detected in the stools of 10 of 30 patients with cholera and in those of 2 of 4 from whom heat-labile Escherichia coli were isolated. None of the stools from nine individuals with Vibrio parahaemolyticus, Salmonella, or Shigella infections were positive. Two of 31 individuals from whom no pathogens were isolated had detectable toxin-like activity in their stools. The Y1 adrenal cell assay provides a rapid method of diagnosing heatlabile enterotoxigenic diarrhea and could be an adjunct in epidemiological studies of gastroenteritis.