Adverse effects of multidrug-resistant tuberculosis treatment with a standardized regimen: a report from Iran.

Compared with the treatment of drug-sensitive tuberculosis, the treatment of multidrug-resistant tuberculosis (MDR-TB) is more difficult. This study was conducted at the national referral center of tuberculosis in Tehran, Iran, to evaluate adverse drug reactions of treatment of MDR-TB. From 2006 to 2009, all patients admitted into Masih Daneshvari Hospital in Tehran, Iran, for MDR-TB were considered for this study. The standard treatment for MDR-TB consisted of amikacin, prothionamide, ofloxacin, and cycloserine. Ethambutol and pyrazinamide were added to treatment if mycobacterium was sensitive to them. All adverse effects observed in patients were recorded in our registry. Eighty patients were considered in the study; of this cohort, 44 were male and 36 were female. The mean age of patients was 40.64 ± 17.53 years (range, 14-81 years). All patients received standardized therapy for MDR-TB. The major adverse effects included neurologic side effects (depression, convulsions, consciousness, psychosis, suicide; 7.5%), hepatitis (5%), rash (1.3%), renal toxicity (3.8%), and auditory toxicity (14.5%). Those with neurologic side effects had less favorable outcome (P value = 0.038) and risk of death was increased among them (odds ratio, 13.8; 95% confidence interval, 2.2-86.77). Other adverse effects did not show statistical significance in our analysis. A major adverse effect such as neurologic side effects (depression, convulsions, consciousness, and psychosis) can result in an increased chance of death among patients with MDR-TB.

Induction of the acid inducible lipF promoter is reversibly inhibited in pH ranges of pH 4.2-4.0.

OBJECTIVE: In the human body pathogenic mycobacteria encounter low pH within the phagosomes of macrophages where they reside after being internalized by the host cell. Low pH within macrophages has been shown to induce expression of a variety of genes within these bacteria. It had been previously observed that the Mycobacterium tuberculosis lipF promoter is transcriptionally upregulated between pHs 4.5-6.4 in Mycobacterium smegmatis, with an upper pH limit of 6.4 capable of promoter induction. To better understand the parameters of acid induced gene expression, we sought to determine the lower pH limit capable of lipF promoter induction. RESULTS: As we had already determined an upper pH limit, we determine here that there is a lower limit of pH's capable of upregulating the lipF promoter, with pH below 4.3 not positively upregulating the promoter. At non-inducing pH 4.2 the bacterial cells remain viable in the absence of acid induced lipF promoter upregulation and subsequent exposure to acid pH 5.0 results in lipF promoter upregulation. There appears to be a lower limit of pH capable of upregulating lipF promoter expression and this limit is not due to cell death.