The influence of mutation gene rpoB of Mycobacterium tuberculosis cluster I (507-534) on the elimination 25-desacetyl rifampicin in urine of tuberculosis subjects

The study aimed to evaluate the influence of mutation gene rpoB of Mycobacterium (M.) tuberculosis cluster I (507-534) on the elimination of 25-Desacetyl Rifampicin (25-DR) in the urine of tuberculosis (TB) subjects. Early morning sputum took from patient TB before treatment. Urine collected after 2 hours taken Fixed-Dose Combination (FDC) at days 7th treatment. All sputum were sequencing at Macrogen Korea Laboratory. Urine was analyzed by high-Performance Liquid Chromatography (HPLC) using the method of Lily et al. Mean (standard deviation) for mutation and non-mutation of rpoB M. tuberculosis group were 7.6147 (4.4478) and 4.5772 (1.7532) μg/ml, respectively. Shapiro-Wilk test showed normally distributed data, with significance 0.3. Independent t-test performed p-value 0.167 and confidence interval (CI) from -1.648 to 7.723. The mutation gene rpoB of M. tuberculosis cluster, I (507-534) in this study, did not affect elimination 25-DR in theurine of TB subjects statistically and clinically.


Introduction
Drug-resistant TB continues to threaten global TB control and remains a major public health concern in many countries. [1] Rifampicin (R) resistance (r) is a reliable marker of Multi-Drug Resistance (MDR)-TB since by far the majority of Rr strains are also isoniazid (INH) resistance. Rr in M. tuberculosis associated with amino acid changes in the subunit of RNA polymerase, encoded by rpoB.The majority (90 to 95%) of mutations responsible for resistance are located in the 81-base pair [2] of cluster I-the so-called Rr determining theregion (RRDR) of rpoB [3], which includes codons 507to 534, encoding 27 amino acids. DNA sequencing of this region could use as a clinical marker for probe assay of mutation and treatment. [4] TBtreatment requires multiple drugs [5], the advance in pharmacology and pharmaceutics have contributed to creating a tablet comprising a combination of several kinds of anti-TB medicines without disturbing the bioavailability of those drugs in one fixed dose, known as FDC. One of the FDC types available in the market is the combination of R, INH, pyrazinamide (PYR), and ethambutol (ETM), commonly called as a4-FDC tablet. The combination of a 4-FDC has potent bactericide and has a low toxicity; therefore, it can use as the first choice for the treatment of TB. [6] The bioavailability of R is important in FDC. [7] R has been shown to undergo a process of deacetylation in animals and man; thediacetyl derivative showed an increased polarity as compared to the parent compound. The diacetyl derivatives are present in bile, serum,and urine after several hours of antibiotics administration. [8] R is excreted about 20% of the administered dose as R plus DR over a 24 h period. [9] WHO recommended the use of HPLC for analysis of TB 4-FDC tablet using two separate systems in which R is set apart due to its stability consideration. [6] The present study was undertaken to assess the influence of mutation gene rpoB of M. tuberculosis cluster (507-534) on the elimination 25-DR in the urine of pulmonary tuberculosis subjects who had FDC.

Study design
Type of study was aquasi-experimental method.The protocol study was approved by the Health Research Ethical Committee of North Sumatera c/o Medical School, Universitas Sumatera Utara, Jl. Dr. Mansyur No. 5, Medan-20155, Indonesia.

Study Subjects
Subjects were taken using purposive sampling technique. The criteria inclusions were pulmonary TB male or female patients diagnosed by a pulmonary physician at Polyclinic Directly Observed Treatment Short Course (DOTS) RSUP. Haji Adam Malik Medan, age >18 years, no antituberculosis treatment drug for at least 2 weeks. Criteria exclusion were pregnancy, HIV infection, stage renal or hepatic disease.Those subjects were willing to participate and gave written informed consent.

Processing Collection Specimen
Subjects were treated by a pulmonary physician, with therapeutic doses of the intensive phase FDC tablets, according to the DOTS strategy. Subjects were administered FDC orally with a glass of water (± 150 ml) after 8 hours an overnight fasting. No food or beverages permitted for two hours following the administration.

Sample collection
The eligible patients were asked to provide early morning expectorated sputum before treatment. Post urine samples were collected 2 hours after taking FDC tablets, at day 7 th treatment.

The presentation of numeric data distribution.
The study data normally distributed, so that, the numerical data urine metabolite levels of 25-DR weredescribed in the concentration measure (mean), size of spread (standard deviation (SD)) and graph (error bar). [13] The mean values, as well as the standard deviation (SD) from the numerical data urine metabolite of 25-DR forgroups of the mutation and nonmutation M. tuberculosis, were 7.6147 and 4.5772, 4.4478 and 1.7532 µg/ml, respectively. The number (n) of samples per group of mutation and nonmutation M. tuberculosis, mean (SD) from data of urine metabolite 25-DR and error bar graph presented with amean (SD) showed in table 2 and figured 1.

Discussion
The ability of M. tuberculosis to harbor multiple drug resistance mutations while retaining the ability to infect, persist, and cause disease in human host raises fundamental questions. [3]In this study, sequencing results from Macrogen Korea Laboratory revealed mutation M.tuberculosis in one group (n=6) and nonmutation in another group (n=6). The impact of drug resistance on the host-pathogen interaction remains largely unexplored.The interaction between M. tuberculosis and human host is complex and dynamic. [3] M. tuberculosis can potentially infect tissues and organs throughout the body.The pharmacokinetic (PK) of a whole-body framework may be of use in quantifying drug-bacteria interactions in organs such as the lungs and spleen as well as providing drug concentrations in locations relevant to drugdrug interactions and toxicity, such as the liver and kidneys. Determination of the clearance would be better using experimental measurements of the time of excretion from bile and elimination R in urine. [5]The recent study, metabolite urine 25-DR was measured by HPLC.The data obtained, processed and fed into each group of mutation and nonmutation M. tuberculosis. The mean (SD) metabolite urine 25-DR of the mutation group was obtained 7.6147 (4.4478) and nonmutation 4.5772 (1.7532) μg/ml.
The information about relationships PK-pharmacodynamic (PD) of drugs against M. tuberculosis still limited. [14] A particular dose does not lead to a specific concentration-time profile in all patients, but rather a distribution determined in part by alleles of genes encoding enzymes involved in xenobiotic metabolism.
[15]R interfereswith transcription and elongation of RNA by binding to the DNA-dependent RNApolymerase M. tuberculosis.
[16] The pathogen response to a particular drug concentration profile is itself related to several PK/PDfactors. Drug resistance in M. tuberculosis was shown to be related to PK/PD factors, and factors such as PK variability. The appearance of drug resistance depends on the exposure of the drug and in many situations the actual form of the concentration-time curve, which is often different from the PK/PD parameters associated with microbial killing. Poor PK/PD exposures due to non-optimize dose regimens, initiate a chain of evolution, starting with induction of multi-drug efflux pumps, then the development of chromosomal mutations, which together lead to high-level MDR-TB and Extensively Drug Resistance (XDR)-TB.
[15] Unexpectedly, the key finding of this study, field conditions real-life and not in the controlled environment of a dedicated PK unit, is that measured levels of metabolite urine 25-DR for agroup of mutation and nonmutation M. tuberculosis were highly variable with p = 0.167 and meant difference (CI 95%) 3.0375 (-1.648-7.723).

Conclusion
Based on the result of the study, it can conclude that there is no significant difference (p> 0.05) between agroup of mutation and nonmutation gene rpoB M. tuberculosis to urine metabolite 25-DR.