A possible mechanism of macrolide resistance among multiple resistant Campylobacter jejuni and Campylobacter coli isolated from Thai children during 1991-2000.

A total of 495 Campylobacterjejuni and 122 C. coli isolated from Thai children were screened for macrolide (erythromycin and azithromycin) resistance by disk diffusion assay. Minimum inhibitory concentrations for erythromycin, azithromycin, nalidixic acid, ciprofloxacin, tetracycline, streptomycin, gentamicin and chloramphenicol were further determined for these macrolide-resistant Campylobacter isolates. Presence of known point mutations resulting in reduced susceptibility to macrolides was investigated by PCR and DNA sequencing. Seventeen percent (23/122) of C. coli and 2.4% (12/495) of C. jejuni isolates were resistant to macrolides. By sequencing domain V of the 23S ribosomal DNA from all 35 macrolide-resistant isolates, a known point mutation of 23S rRNA associated with reduced susceptibility to macrolides was detected in all isolates except one. Among the macrolide-resistant isolates, all were multiply resistant to nalidixic acid and ciprofloxacin, of which the latter is the preferred antimicrobial used for diarrheal treatment in Thailand. Furthermore, most macrolide-resistant isolates were also resistant to tetracycline and streptomycin. The spread of macrolide and quinolone resistant Campylobacter should be monitored closely in Thailand and elsewhere as these antimicrobials are preferred drugs for treatment of diarrhea.

Practice of using human excreta as fertilizer and implications for health in Nghean Province, Vietnam.

The ancient practice of applying latrine wastes to agricultural land has maintained soil fertility in Vietnam for several centuries but may be associated with health risks if the wastes are inadequately treated before usage. This study aimed at investigating the perceptions and handling practices using latrine wastes as fertilizers in a community in central Vietnam. Information was collected through structured questionnaire interviews administered to 75 farming households, focus group discussions, and key informant interviews. The majority (64%) of households had a single vault latrine, a possession that was associated with low income (chi2= 12.45; p < 0.05). Most households (85%) used latrine waste in agriculture that was composted before usage (98%). Households often mixed the composted excreta with kitchen ashes and powdered lime likely to increase pH and pathogen die-off. About 28% of households that were applying latrine waste as fertilizer composted three to six months, and only 11 (18%) households composted human excreta for more than the recommended six months. Households with double vault latrines were 7.8 (chi2= 9.4; p<0.05) times more likely to compost human excreta more than six months as compared with households having single vault latrine. Most farmers distributed the latrine wastes with bare hands (66%) because of convenience during application. Respondents with a high educational level used protective gloves more often when distributing latrine wastes in the fields compared to respondents with a low educational level (chi2 = 7.6; p<0.05). If any negative health impacts of latrine waste use in agriculture are to be reduced, then it is suggested that sustainable interventions should take into consideration farmers current excreta-use practices.

Antimicrobial resistance of Shigella spp isolated from diarrheal patients between 1989 and 1998 in Vietnam.

Shigellosis is an important cause of infectious diarrhea in Vietnam, caused mainly by Shigella flexneri. This study provides for the first time in the international literature, data on the development of antimicrobial resistance in Shigella between 1988 to 1998, including data reported to the National Program for Surveillance of Antimicrobial Resistance (NPSAR). Our studies show that about 80% of the Shigella strains tested were resistant to ampicillin, chloramphenicol, oxytetracycline, trimethoprim and sulfonamides. This combination of drugs was also the most common antibiogram among multiple-resistant S. flexneri (57%). Resistance to tetracyclines, sulfonamides and, in particular trimethoprim (p<0.001), increased during the study period. Our findings indicate that tetracyclines and co-trimoxazole (a combination of a sulfonamide and trimethoprim), which are recommended and commonly used drugs for the treatment of shigellosis in Vietnam, may have limited therapeutic effect. In contrast to neighboring countries, low percentages of resistance were found to nalidixic acid and norfloxacin (3-5%) and no resistance was found to ciprofloxacin, indicating that nalidixic acid with its low cost and safety in children could be recommended for the treatment of shigellosis. The NPSAR provides a useful picture of the levels and development of antimicrobial resistance in Vietnam and should receive continued support for further improvement by increasing the number of provinces covered, the numbers of isolates tested from rural areas, and the communication of results to medical practitioners and others prescribing and/or selling antimicrobials.