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.

Epidemiological analysis of methicillin resistant Staphylococcus aureus in Thailand.

The geographical distribution of 65 clinical isolates of methicillin resistant Staphylococcus aureus (MRSA) recovered from 7 hospitals in Thailand was investigated. The presence of mecA gene in MRSA was determined by specific PCR with the use of primers 5'-GTAGTTGTCGGGTTTGGT-3' and 5'-GGTATCATCTTGTACCCA-3'. Chromosomal DNA restriction analysis with SmaI was resolved by pulsed-field gel electrophoresis (PFGE) compared with antibiotype analysis and phage type analysis. All 65 strains carried mecA gene. They all were resistant to penicillin, tetracycline, erythromycin, amoxicillin/clavulanic acid and variably resistant to gentamicin, ofloxacin, trimethoprim-sulfamethoxazole, chloramphenicol, fosfomycin and clindamycin; and all isolates were susceptible to vancomycin. A total of 19 PFGE patterns designated as type A, A1, A2, A3, A4, B, B1, C, D, E, E1, E2, F, F1, F2, G, H, I and J was identified. Type A4 and E were commonly found in every studied areas. Phage typing showed even greater variability that 52 (80%) isolates belonged to 25 different phage types; 13 (20%) isolates were non-typable. The clarity and polymorphism of the PFGE patterns enable us to discriminate between isolates which could not be differentiated by antibiogram or phage type analysis. The findings demonstrate the existence of a common epidemic MRSA clone in Thailand.

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.

Multifactorial pathogenic mechanisms of Burkholderia pseudomallei as suggested from comparison with Burkholderia cepacia.

With the purpose to elucidate the pathogenesis of disease due to Burkholderia pseudomallei some biological and biochemical properties of this species were studied in comparison with B. cepacia, since the difference in the level of virulence between the two species is remarkable despite of their toxonomic closeness. B. pseudomallei was distinct from B. cepacia in the capability to grow under anaerobic conditions, with positive nitrate respiration, excretion of high-molecular polysaccharides into liquid culture, and cytotoxicity against cultured tissue cells. From these observations together with our previous finding that B. pseudomallei can grow and survive in an acidic environment, we suggest multifactorial mechanisms for the pathogenesis of melioidosis due to B. pseudomallei.

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.

Clostridium difficile associated disease in Thailand.

Over a twenty-six month period 383 fecal specimens from 269 diarrheal patients and 114 control patients were examined for Clostridium difficile and its cytotoxin. C. difficile was isolated from 13 (4.8%) of overall age group of diarrheal patients and from 3 (2.6%) of controls. Fecal cytotoxin was detected in 106 (52.5%) of 203 diarrheal patients and in 17 (22.4%) of 76 controls. Sixty-one percent of antibiotic-associated diarrheal patients (less than 3 years) and 51% of non-antibiotic associated diarrhea patients had fecal cytotoxin. Enteric pathogens other than C. difficile were detected in 0.7-7.4% of the patients studied. These data suggest that C. difficile associated disease may be frequently encountered in such a developing region studied. Routine diagnosis for C. difficile in diarrheal patients appears to be warranted.