Bacterial causes of AIDS-associated diarrhea in Thailand.

The incidence of bacterial diarrhea in AIDS patients has increased steadily and has led to enormous medical and public health problems. In this study, the clinical data together with 350 rectal swab samples each from AIDS patients with diarrhea (APD) and non-AIDS patients with diarrhea (NAPD), were collected and examined for bacterial enteropathogens at the Bamrasnaradura Infectious Diseases Hospital (BIDH), Nonthaburi, Thailand from May to December 1996. Patients were matched by age and sex. The majority of these patients were male (79%, 554/700), aged between 15 and 34 years (70.9%). The study found that the isolation rates of bacterial enteropathogens causing diarrhea in APD (18%, 62/350) were considerably lower than those in NAPD (43%, 152/350) (p<0.05). The infection rate with Salmonella group B (19.7%, 12/61) in APD was found to be significantly higher than that in NAPD (14.3%, 2/14) (p<0.05). Vibrio parahaemolyticus (53.3%, 81/152), Plesiomonas shigelloides (27%, 41/152), Aeromonas spp (19.1%, 29/152) and V. cholerae O1 (15.1%, 23/152), were more frequently detected in NAPD than in APD (p<0.05). Only nine Escherichia coli strains were isolated from APD, of which six were enteroinvasive E. coli, two enterotoxigenic E. coli and one enterohemorrhagic E. coli (non O157) possessing both vtl and vt2. No V. cholerae strains were detected in APD. The least effective antibiotics were ampicillin, tetracycline and cotrimoxazole. Antibiotic resistant patterns of the isolated organisms were similar from both groups. The results from this study might be useful in Thailand in the diagnosis and management of clinical cases of bacterial diarrhea, especially APD.

Bacterial contamination of bottle milk in infants under 6 months in Children's Hospital, Bangkok, Thailand.

The bacterial contamination of bottle milk samples obtained randomly from 500 infants under 6 months of age who came to the Out-patient Department of Children's Hospital Bangkok was determined by collecting bottle milk samples prepared at home following interview of their caretakers after obtaining their consent. Bacterial contamination was found in 91.8% (459/500) of bottle milk samples. Among the positive samples, 82.8% (380/459) contained enteric bacteria, another 17.2% were unidentified bacteria. The dominant enteric bacteria isolated from bottle milk were Klebsiella spp (56.6%), Enterobacter spp (41.3%), Aeromonas spp (14.4%), E. coli (13.4 %) and Vibrio cholerae non 0-1 (1.8%). Isolated E. coli were further identified as enteropathogenic E. coli (7.8%, 4/51) and enterotoxigenic E. coli (3.9%, 2/51). About 74% of the contaminated bottle milk contained one type of bacteria, 23.7% had two types and 2.3 % had 3 or more types of bacteria. A level of bacterial contamination greater than the US government limited number (USGLN 2x10(4) CFU/ml) was found in 86.4% of total examined samples (432/500) [geometric mean (GM) of 2.9 x 10(6) CFU/ml]. About 66% (333/500) of bottle milk samples had coliforms greater than the USGLN (1 x l0(2) CFU/ml) with GM of 1.3 x 10(4) CFU/ml. Therefore, in the preparation of bottle milk, feeding practice should be emphasized in every setting of maternal-child health care and promotion of breast-feeding should be encouraged by the health personnel.

Overview reflection of primary health care in Thailand supported from 1976 to 1996 by Japan-Thailand partnership.

The international health cooperation of Japan for developing countries has been mostly concentrated on matters such as improvement of hygienic environment, prevention of tropical infectious diseases, establishment of hospitals with modern medical instruments and devices, and dispatch of medical experts. PHC (Primary Health Care) activities based on voluntary participation of local inhabitants in developing countries have been largely neglected. In the field of health and medical care, sufficient effect may not be achieved unless the local health activity is based on voluntary participation of the inhabitants. The introduction of advanced modern medical technics may be beneficial to some of the inhabitants, while most of the local inhabitants may not have the chance to receive such benefits, and additionally it is difficult to propagate modern medical care and technics widely to rural areas. In Thailand, PHC activity based on community participation was started in 1985, with the following three main themes: (1) Training of Village Health Volunteers (VHV) and Village Health Communicators (VHC), and development of their activities. (2) Establishment and operation of Health Centers. (3) Establishment and operation of a Drug Cooperative System (DC). Earlier, one of PHC activities developed by Japan, "Thailand Local Health Activity Improvement Project" based on the program of Thailand-Japan Partnership, was initiated in 1976 in rural areas of Chanthaburi Prefecture. From 1982, third country training programs have been carried out by the Japan International Cooperation Agency (JICA). As 10 years have elapsed since the initiation of PHC activity in rural areas in Thailand under the cooperation of the Governments of Thailand and Japan, it seems to be time to reconsider how PHC activity should be developed in future based on a candid evaluation of achievements and results.

Monoclonal antibody-based dot-blot ELISA for the detection of Salmonella in foods.

Monoclonal antibody (MAb) produced to polysaccharides in the LPS molecule of salmonellae was used in a dot-blot ELISA for detecting Salmonella in 873 food samples, ie 100 fresh chicken, 261 frozen chicken, 78 pork, 84 beef, 100 hen eggs, 100 duck eggs, 50 sea-mussels, 50 shrimps and 50 squids in comparison with the conventional culture method. Salmonella culture from foods involved the following steps: pre-enrichment, enrichment in selective medium, isolation on selective and indicator media, followed by biochemical and serological identification of appropriate colonies, respectively. The whole culture procedure took 5 days. Food samples from the selective enrichment medium were also subjected to the MAb-based dot-blot ELISA. The whole procedure of dot-blot ELISA took less than 2 hours. Among 873 food samples, salmonellae could be recovered from 7.4% of the samples by the bacterial isolation method (16% of fresh chicken, 8.8% of frozen chicken, 24.4% of pork, 3.6% of beef and 2% each of hen eggs and duck eggs, respectively). Salmonella derby were predominant among pork samples while S.paratyphi B biovar java predominated in chicken. The MAb-based dot-blot ELISA were positive in 19.5% of the food samples, i.e. 30% of fresh chicken, 27.6% of frozen chicken, 34.6% of pork, 21.4% of beef, 20% of shrimp, 16% of sea-mussels, 2% of hen eggs and 4% of duck eggs. The sensitivity and specificity of the MAb-based dot-blot ELISA compared to the bacterial culture method were 81.5% and 85%, respectively. The discrepancy of the data between the culture method and the dot-blot ELISA might be due to the fact that the culture method could detect only living cells at numbers that gave at least one isolated colony on the selective/differential plate while the dot-blot ELISA detects any form of Salmonella antigen. The monoclonal antibody-based dot-blot ELISA offers several advantages over the conventional bacterial culture method when it is used for screening of Salmonella contamination in foods, especially export foods. These include rapidity, cost-effectiveness and simplicity (the dot-blot ELISA does not need highly trained personnel or equipment, in contrast to the culture method). The test can be performed in field conditions and the result can be read visually. It also offers multisample analysis at one time which renders more samples of food for screening possible, thus false negative results are fewer which, in turn, assures the quality of the export food in a cost-saving, short time frame.

First isolation of Salmonella blockley in Thailand.

The first isolation of Salmonella blockley in Thailand was found in 2 strains of animal feed samples and 3 strains of chicken feather samples from a private poultry company in 1989. From 1987 to 1992, the number of S. blockley isolates increased and found in various sources. The major sources were the stools of diarrheal patients, mainly children. Another source of S. blockley was frozen chicken meat which increased every year studied. S. blockley isolated from human and other sources showed a high percentage resistance to streptomycin, tetracycline, kanamycin and chloramphenicol and a low percentage resistance to ampicillin and cotrimoxazole. Thus, S. blockley must now be listed as a possible cause of Salmonella food poisoning in Thailand.

Retroviral reverse transcriptase inhibitory activity in Thai herbs and spices: screening with Moloney murine leukemia viral enzyme.

Fifty-seven Thai herbs and spices were examined for their retroviral reverse transcriptase inhibitory activity. All herbs and spices were extracted with hot-water and methanol. Reverse transcriptase inhibitory activity of the extracts was determined by using Moloney Murine Leukemia Virus reverse transcriptase (M-MuLV-RT) reacted with 3H-dTTP and radioactivity measured with a scintillation counter. Eighty-one per cent (46/57) of hot-water extracts and 54% (31/57) of methanol extracts showed inhibitory activities. At a concentration of 125 micrograms/ml, 13% (6/46) of hot-water extracts, namely Eugenia caryophyllus Bullock et Harrison, Phyllanthus urinaria Linn., Terminalia belerica Roxb., Nelumbo nucifera Gaertn., Psidium guajava Linn. and Lawsonia inermis Linn., had a relative inhibitory ratio (IR) over 50%. They showed ratios of 100%, 91%, 75%, 74%, 61% and 60%, respectively. For methanol extracts, only 10% (3/31) had IR values over 50%. They were T. belerica, E. caryophyllus and N. nucifera which exhibited IR values of 83%, 54% and 54%, respectively.

Dot-ELISA for seroepidemiological study of exposure to Shigella flexneri.

A seroepidemiological study for determining serum antibodies to lipopolysaccharides (LPS) of Shigella flexneri using dot--ELISA was carried out in Krabi Province, Thailand, from January 1989 to December 1990. From 363 serum samples obtained from cord blood and from venous blood of the healthy persons aged from 6 months to over 50 years, 56% and 22%, respectively, were found to be positive for specific IgG and IgM antibodies to S. flexneri LPS. The IgG prevalence was initially detected at 3-4 years of age and then rose sharply with age. In contrast, IgM was detectable earlier, with much lower prevalence than that of IgG. The highest seroprevalence values were in the age groups 30-49 years for IgG and 15-19 years for IgM. The seroprevalence of S. flexneri infection was statistically higher among males, Buddhists, businessmen, and those with elementary education. S. flexneri infection was not associated with family income, home location, eating behaviour or water supply. These seroepidemiologic data demonstrated that most of the population in Krabi Province had been infected with S. flexneri.

Bacteriophage typing of Vibrio fluvialis.

Six stable bacteriophages of Vibrio fluvialis were isolated from 44 surface water specimens collected in Thailand and Japan. Twelve different phages types were found among 109 V. fluvialis isolated from feces of diarrheal patients and the environment. Seventy-three percent (80/109) of these 109 isolates were typable with these phages. One phage type, designated as A (1) was predominant and accounted for 43% of the V. fluvialis examined. The six bacteriophages used in this typing scheme were stable for at least during a three-month storage at 4 degrees C. This proposed bacteriophage typing scheme may be of valuable aid in tracing sources and routes of infection in outbreaks of V. fluvialis infection in man.

ELISA for seroepidemiological study of exposure to Vibrio cholerae of population in Krabi Province, Thailand.

Seroepidemiological study of Vibrio cholerae exposure was carried out in Krabi Province during January 1989 to December 1990 using indirect ELISA to determine serum antibodies to lipopolysaccharides (LPS) of V. cholerae. Among 363 serum samples obtained from cord blood and venous blood of healthy persons, aged from 6 months to over 50 years, 65% and 64% were found positive for specific IgG and IgM against LPS of V. cholerae, respectively. The seroprevalence of V. cholerae infection increased with age from that found at 6 months, being highest in the age groups of 30-49 years for IgG and 15-29 years for IgM. The seroprevalence of V. cholerae infection was higher among female Muslims and home-makers, and increased with the family income. The seroprevalence of cholera infection was also influenced by home location, methods of food storage and water supply. These data suggested that a large number of Krabi's population had V. cholerae infection.

A comparison of methods for the isolation of Campylobacter species from stool specimens.

Eight methods used for isolation of Campylobacter species were compared. Using a combination of methods Campylobacter species were isolated from 30 (11%) of 270 children with diarrhea seen at Bamrasnaradura Infectious Disease Hospital, Nonthaburi, Thailand. The membrane filter method using a gas generating envelope at 37 degrees C identified 73% of the total positive specimens and was found to be the best isolation method for Campylobacter species from stool specimens. This method identified two strains that failed to grow on antibiotic containing media, and also gave a higher isolation rate of C. jejuni than could be isolated with conventional methods. The combination of the membrane filter method and a selective antibiotic method identified 90% of all isolates. At present the cost of the membrane filter method is higher than other methods. Therefore, the selective antibiotic method (Campy-BAP) with sheep blood under gas mixture at 42 degrees C is recommended for laboratories with limited supplies. Diagnosis by direct smear with 1% basic fuchsin revealed high degree of sensitivity and specificity. This rapid, inexpensive, and simple method could be used to make a presumptive diagnosis of Campylobacter enteritis when isolation methods are unavailable.