Isolation and identification of Mycobacterium avium complex and other nontuberculosis mycobacteria from drinking-water in Basra governorate, Iraq

This study aimed to determine the occurrence of Mycobocterium avium complex and other nontuberculous mycobacteria in drinking-water in Basra governorate, Iraq and their susceptibility to several antibiotics and the effect of 0.5 mg/L of chlorine on their survival. A total of 404 samples of drinking-water were collected from 33 different districts of the governorate from November 2006 to August 2007. Filtered samples were incubated for 7 days or less in a monophasic-biphasic culture setup of tuberculosis broth and Lowenstein-jensen agar. The 252 isolates were identified as M avium complex [21], M. marinum [15], M. kansasii [30], M. simiae [20], M. szulgai [19], M. xenopi [16], M. malmoense [11], M.fortuitum [37], M. chelonae [50] and M. abscessus [33]. Isolates were tested for antibiotic susceptibility as well as their ability to tolerate chlorine at a concentration of 0.5 mg/L The presence of these pathogenic bacteria in drinking-water renders the water unfit for human consumption

Clarithromycin Susceptibility Testing of Mycobacterium avium Complex Using 2,3-Diphenyl-5-thienyl-(2)-tetrazolium Chloride Microplate Assay with Middlebrook 7H9 Broth

A series of 119 Mycobacterium avium complex isolates were subjected to clarithromycin susceptibility testing using microplates containing 2,3-diphenyl-5-thienyl-(2)-tetrazolium chloride (STC). Among 119 isolates, 114 (95.8%) were susceptible to clarithromycin and 5 were resistant according to the new and the standard method. STC counts the low cost and reduces the number of procedures needed for susceptibility testing.

Clarithromycin Susceptibility Testing of Mycobacterium avium Complex Using 2,3-Diphenyl-5-thienyl-(2)-tetrazolium Chloride Microplate Assay with Middlebrook 7H9 Broth

A series of 119 Mycobacterium avium complex isolates were subjected to clarithromycin susceptibility testing using microplates containing 2,3-diphenyl-5-thienyl-(2)-tetrazolium chloride (STC). Among 119 isolates, 114 (95.8%) were susceptible to clarithromycin and 5 were resistant according to the new and the standard method. STC counts the low cost and reduces the number of procedures needed for susceptibility testing.

Drug resistance profile of human Mycobacterium avium complex strains from India.

PURPOSE: To determine minimum inhibitory concentration (MIC) of various anti-tuberculosis drugs for Mycobacterium avium complex (MAC) strains isolated from clinical samples. METHODS: Forty-nine human isolates of MAC were tested for susceptibility to nine chemotherapeutic agents. All isolates were from Indian patients suffering from chronic pulmonary mycobacteriosis. Drug susceptibility was performed both by agar dilution and MIC method. MIC values were analysed, both visually and by enzyme-linked immunosorbent assay reader. RESULTS: More than 40% of the MAC isolates were sensitive to ciprofloxacine (48.98%), amikacin (46.94%) and roxithromycin (42.86%) by the MIC method. In contrast, the isolates showed high degree of resistance to the first line antituberculosis drugs: only 28.6% were sensitive to rifampicine, 22.85% to isoniazid and ethambutol each and 36.7% were sensitive to streptomycin. In addition, 22.85% of the strains were sensitive to clofazimine and 34.7% to kanamycin. CONCLUSIONS: Results of the study confirm the suitability of the rapid broth micro dilution (MIC) method as a simple yet reliable method to assay for the drug susceptibility of nontuberculosis mycobacterium.

Mycobacterium avium complex in HIV-infected Thai children.

Of the 169 human immunodeficiency virus (HIV)-infected children being cared for at Siriraj Hospital from January 1998 to September 2000, 10 had Mycobacterium avium complex (MAC) infection; seven had disseminated disease and three had MAC pneumonia. Nine children were in the advanced stage of HIV disease at the time of diagnosis with the median CD4 count of 7 cells/mm3 and 127 cells/mm3 and the median age of 65 months and 63 months in disseminated MAC and MAC pneumonia respectively. None of these children had received prior chemoprophylaxis. Common clinical findings included prolonged fever, weight loss, lymphadenopathy, hepatosplenomegaly, diarrhea, anemia and leukopenia. The outcome of MAC infection was poor, with a mortality rate of 60 per cent. In in vitro susceptibility testing, clarithromycin was the least resistant drug. With the incidence rate of 2.15 per 100 person-years, the high rate of antimicrobial resistance, and the poor outcome, primary chemoprophylaxis for MAC infection in conjunction with effective antiretroviral therapy should be considered for Thai children in the advanced stage of HIV infection.

Experiencia de una década en la tipificación y resistencia a fármacos antituberculosos en micobacterias aisladas de pacientes VIH+/SIDA / Ten years experience in practicing identification and susceptibility tests on mycobacteria isolated from HIV+/AIDS patients

El análisis de las pruebas de tipificación y de la resistencia a fármacos antituberculosos de micobacterias aisladas de pacientes seropositivos al VIH, en la década de los noventas, mostró una proporción de micobacterias no tuberculosas de 23,6 por ciento y una resistencia primaria y adquirida a los fármacos antituberculosos de primera línea de 17,5 por ciento y 43,9 por ciento respectivamente; estas cifras son significativamente más elevadas que las observadas en enfermos tuberculosos VIH(-). Estos hallazgos confirman la conveniencia de continuar la práctica sistemática de las pruebas mencionadas en todo aislamiento de micobacterias proveniente de pacientes VIH+, para adecuar oportunamente y de acuerdo a sus resultados, los esquemas terapéuticos a emplear

Correlation between inhibitory effect of quinolones and mycolic acid metabolism in mycobacteria.

Mycolic acids are important components having a significant role in maintaining the rigidity of mycobacterial cell wall. They could also be the barrier for penetration of certain drugs into the bacterial cell. A novel in vitro model system was established for assessing the effect of Ciproflaxacin on mycolic acid metabolism in pathogenic mycobacteria M. Kansasii (which has similar mycolic acid pattern to that from M. leprae) and the effect of norfloxacin in M. intracellulare. These test mycobacteria were exposed in their midlogarithmic phase of growth to 0.5, 1, 2, 3, 4, 5 and 6 micrograms ml of ciprofloxacin and norfloxacin respectively for 1, 2 and 24 hours. Ciprofloxacin completely inhibited the synthesis of mycolates in M. kansasii at 3, 4 and 5 micrograms/ml; whereas norfloxacin exhibited its maximum inhibitory action on mycolic acids in M. intracellulare at 6 micrograms/ml for all the durations of exposure. Inhibition of mycolates directly correlated with bacterial viability which was estimated by colony forming units. The effect of quinolones on mycolic acid metabolism appears to be direct and not secondary to DNA gyrase. The results obtained from this study and our previous findings show that mycolic acid metabolism is affected by various groups of drugs, whose primary sites of activity may be different. The findings of the present study may have significant therapeutic implications in leprosy and other mycobacterial diseases.