Susceptibility of Salmonella typhi to chloramphenicol, ampicillin and cotrimoxazole.

Salmonella typhi isolated from the patients admitted to the Hospital for Tropical Diseases, Bangkok, were tested by the tube dilution method and the disc diffusion method against chloramphenicol, ampicillin and cotrimoxazole. Forty-five percent of the S.typhi were resistant to chloramphenicol (MIC greater than or equal to 50 microgram/ml) while 5% were resistant to ampicillin (MIC greater than or equal to 12.5 microgram/ml). Only 1% of the S. typhi was found to be resistant to cotrimoxazole (MIC greater than or equal to 168 microgram of trimethoprim + sulfamethoxazole per ml.) Based on these results, the drug of choice for typhoid fever would be cotrimoxazole, especially when drug sensitivity test is not immediately available.

Serological studies on possible causes of intra-uterine infections in Thai infants.

Serological tests for toxoplasmosis, rubella, cytomegalovirus (CMV), Herpesvirus hominis (HVH) infections syphilis (TORCHES) were carried out in 49 infants with showed signs of possible intrauterine infections and in 212 mothers and their newborn infants. The tests employed were ELISA for rubella and CMV infections, indirect haemagglutination for HVH infection and toxoplasmosis and RPR Macro-vue card test for syphilis. The immunoglobulin class of the antibody was also determined, and only infants with IgM antibody was considered indicative of intrauterine infection. It was found that 36.7% and 10.2% of infants with signs of intrauterine infections were positive for rubella and CMV antibodies and 19% had mixed infections of rubella, CMV, toxoplasma, syphilis and HVH. In contrast, only 6.1% of normal newborn infants had rubella antibody, 6% had HVH antibody and less than 1% had toxoplasma antibody, and none of them had CMV and treponema antibodies. Higher rate of seropositivities were found in their mothers, the percentage seropositivities for rubella, HVH, CMV infections, syphilis and toxoplasmosis were 19%, 12%, 2% and 1% respectively.

Incidence of bacteremia in patients with opisthorchiasis during recurrent cholangitis.

A total of 257 haemocultures were performed in 50 patients with opisthorchiasis when they presented signs and symptoms of biliary tract infection. 19 patients showed positive haemoculture. There are no significant relationship between the age of the patient and the incidence of positive haemoculture. Septic shock occurred in 5 patients, one patient died. Out of 221 aerobic cultures, 14% were positive and of the 36 anaerobic cultures 11% were positive. The most common organism was Staphylococcus followed by Klebsiella and Bacillus spp. Anaerobic bacterias were Streptococcus spp. Clostridia spp. was not found in this study. Most organisms were sensitive to cefotaxime, cephalothin, kanamycin and chloramphenicol, and the least sensitive to ampicillin.

Sphingobacterium multivorum septicemia: a case report.

A 47-year-old man presented with a history of fever, chills and weight loss for 3 months. He had been treated for diabetes mellitus during the past 3 years. He developed high fever with abnormal liver function tests. Both Widal and Weil-Felix reactions were negative with normal roentgenogram of the chest. His anti-HIV tests were positive. The cultures from the blood and sputum yielded pure Sphingobacterium multivorum sensitive to sulfamethoxazole-trimethoprim, chloramphenicol, tetracycline, cefotaxime, ceftazidine and ceftriaxone. On the next day, the patient developed signs and symptoms of meningitis with the CSF containing chronic and acute inflammatory cells but revealed no growth on culture. The patient was treated with a combination of ceftriazone and trimethoprim-sulfamethoxazole but he died on the 6th day after admission. This patient was the fifth reported case infected with S.multivorum. It illustrates that this potentially pathogenic organism can cause septicemia in an immunodeficient patient.

Detection of heat-stable enterotoxigenic Escherichia coli by hybridization with an RNA transcript probe.

Heat-stable enterotoxigenic Escherichia coli was identified by nucleotide hybridization with RNA transcripts of the gene encoding heat-stable A-2 enterotoxin. Radiolabeled enterotoxin gene RNA transcripts are easier to prepare and avoid the preparation of cloned DNA probes that can be nonspecific if they contain cloning vector DNA.

Clinical and bacteriological studies of El Tor cholera after ingestion of known inocula in Thai volunteers.

Twenty-six healthy adult Thai volunteers were recruited for clinical and bacteriological studies of cholera induced by oral inoculation with Vibrio cholerae El Tor Inaba strain N16961. Vibrio dosages of 0.3 x 10(4), 1.6 x 10(5) and 1.9 x 10(6) c.f.u. were given to three groups of five volunteers, and 2.0 x 10(7) c.f.u. to 11 volunteers. Diarrhoeal attack rates correlated positively with the size of the inocula (p less than 0.01). It was estimated that a diarrhoeal attack rate of 90% (ED90) would be achievable by inoculation of 1.3 x 10(7) c.f.u. of the organisms. There were no significant differences between the groups in the latent period to positive stool culture, maximum vibrio count per gram of stool and duration of stool positivity. The ED90 of V. cholerae obtained may be used as a challenge dose in subsequent studies on protective efficacy of cholera vaccines in Thai adult volunteers.

Preliminary assessment of the safety and immunogenicity of live oral cholera vaccine strain CVD 103-HgR in healthy Thai adults.

A single dose (5 x 10(8) organisms) of attenuated A- B+ Vibrio cholerae classical Inaba recombinant vaccine strain CVD 103-HgR or placebo was administered to 24 healthy young Thai adults in a randomized, placebo-controlled, double-blind trial of safety and immunogenicity. None of the volunteers experienced untoward reactions. The vaccine strain was recovered from 2 of 12 vaccines. The vibriocidal antibody response (the best immunological correlate of protection) was good: 11 of 12 vaccinees (92%) manifested significant serotype-homologous Inaba antibody rises with a peak reciprocal geometric mean titer (RGMT) postvaccination of 3,417; 9 of 12 exhibited significant serotype-heterologous Ogawa antibody rises (prevaccination RGMT, 180; peak RGMT, 2,874). Nine of 12 vaccinees had significant rises in serum antitoxin. None of the controls exhibited rises in vibriocidal or antitoxic antibody. This preliminary study further confirms the safety and immunogenicity of CVD 103-HgR live oral cholera vaccine and paves the way for larger community studies of this candidate cholera vaccine.