Clostridium difficile infections in HIV-positive patients.

The prevalence of Clostridium difficile infections in HIV-positive patients with regard to the presence of its enterotoxin was investigated. Enzyme immunoassay (EIA, Meridian Diagnostic Inc) was used for the detection of C. difficile enterotoxin in stool specimens collected from 201 HIV-positive and 271 HIV-negative diarrheal patients. Culture was performed on cycloserine cefoxitin fructose agar. Chromosomal DNA types of C. difficile isolates were determined by pulsed-field gel electrophoresis (PFGE). In the HIV-positive group, C. difficile enterotoxin was found in 58.8% and 12.6% of diarrheal and non-diarrheal patients, repectively, whereas this toxin was found in 36.5% of HIV-negative-diarrheal patients. However, 13.6% of stool samples were negative by toxin assay, but were positive for C. difficile by culture and latex agglutination test. Among 11 isolates from both HIV-positive and HIV-negative patients, 6 patterns of PFGE type were observed: A, B, C, D, E and F.

Isolation rates of Burkholderia pseudomallei among the four regions in Thailand.

This study aimed to compare the isolation rates of Burkholderia pseudomallei among community-based hospitals located in the central, north, northeast, and south of Thailand. A questionnaire inquiring about the number of isolation of B. pseudomallei from various clinical specimens during 1994-95 were mailed to 141 community-based hospitals. Of these, 125 hospitals (88.6%) responded to the questionnaire. Microbiological laboratory was not available in thirty hospitals. Data from 95 remaining hospitals with capability to do bacterial culture showed that B. pseudomallei was never isolated in 49 hospitals. Eleven, 9, 19 and 7 hospitals where B. pseudomallei has been isolated, are located in the central, north, northeast and south of Thailand respectively. From these 46 hospitals, a total of 1,131 strains of B. pseudomallei were isolated from 407,263 specimens in 1994 and 1,165 strains from 440,541 specimens in 1995. However, the isolation was most frequent in northeastern hospitals, which accounted for 890 and 964 strains in 1994 and 1995 respectively while only 94, 76, 71 and 83, 75, 43 strains were simultaneously isolated during the 2-year period in those located in central, north and south respectively. The isolation rates of B. speudomallei in 1994 and 1995 were 4.2 and 4.1 per 1,000 clinical specimens in northeastern hospitals as compared to 1.1, 1.8, 1.1 and 1.1, 1.2, 0.7 in those located in central, north and south respectively. Ubon Ratchathani, Nakhon Ratchasima, Buri Ram, Khon Kaen and Udon Thani were the five provinces which exhibited the highest isolation rates as follows; 244, 150, 147, 127, 100 and 218, 128, 114, 119, 58, in 1994 and 1995, respectively. It was concluded that B.pseudomallei was most commonly isolated in the northeast of Thailand. Under-recognition of B. pseudomallei may prevail not only in other parts of Thailand but in some areas of the northeast as well.

Antibacterial activity of teicoplanin against Clostridium difficile.

The in vitro inhibitory action of teicoplanin, vancomycin, metronidazole and clindamycin against clinical isolates of Clostridium difficile was investigated. Minimum inhibitory concentrations (MICs) were determined using E test. Teicoplanin (MIC range 0.023-0.75 microgram/ml), vancomycin (MIC range 0.5-3 micrograms/ml) and metronidazole (MIC range 0.19-1 microgram/ml) were all very active against the isolates examined. No resistant strains of C. difficile to those three antimicrobial agents were observed, whereas resistance to clindamycin was found in 39.5% of the tested strains. Teicoplanin was about 4-times more potent than vancomycin. It appears to be a more promising antimicrobial for treatment of C. difficile enteric disease.

Environmental surveillance of Legionella species in Thailand.

Legionellae was found in 57 per cent of 94 cooling towers and 21.8 per cent of 78 other environmental sources. These figures reveal that the existence of legionellae in cooling towers is more prevalent than that found in other environmental sources. Legionella pneumophila serogroup 1 was the most prevalent organism among the legionellae found in cooling towers and other environmental sources. The recovery of legionellae in each province was seasonally independent and was found throughout the year. This is the first report of an environmental survey representing the existence of legionellae in every region of Thailand.

A monoclonal antibody-based dot-blot ELISA diagnostic kit for the detection of Vibrio cholerae 01 in stools of diarrheic patients and household contacts.

A "cholera diagnostic kit" was developed for sensitive, specific, rapid, and inexpensive detection of Vibrio cholerae 01. The monoclonal antibody specific to antigen A of Vibrio cholerae 01 was used as an antigen detection reagent and the principle of dot-blot ELISA was adopted. The kits were used in seven Regional Medical Sciences Centres, Ministry of Public Health, located at various regions of Thailand where diarrhea occurs frequently. Diagnostic efficiency of the kits in the detection of Vibrio cholerae 01 from rectal swabs of the diarrheic patients and their household contacts was evaluated in comparison with the conventional culture method. The two methods were found to have excellent degree of agreement (kappa values > 95%). The dot-blot ELISA has several advantages over the culture methods, ie rapid (dot-blot ELISA takes 1-2 hours while the culture method takes at least two days) and inexpensive. It requires no sophisticated equipment. The procedure is not complicated thus it is easy to train personnel. The diagnostic kits are recommended for use in the detection of severe diarrhea caused by V. cholerae 01 not only in hospitals and health centres where adequate treatment of the patients is required as a life-saving measure but also for early recognition of cholera cases and their contacts so that other action, ie prevention and control of outbreaks and surveillance can be promptly implemented.

Reactivity of the CD D-1 latex test with Clostridium difficile and other bacteria.

The reactivity of a commercial latex test with thirty-three species of bacteria was tested. Toxigenic and nontoxigenic strains of Clostridium difficile gave a positive result in the CD D-1 latex test. Cross-reactions were also given by C. putrificum, C. sporogenes and proteolytic C. botulinum.