Frequency of Resistance to Delamanid in Mycobacterium tuberculosis Isolated from Patients with Pulmonary Tuberculosis in the Russian Federation

Resistance to antituberculosis drugs is an important cause of treatment failure. We evaluated the prevalence and pattern of antituberculosis drug resistance in the central region of Saudi Arabia, and reviewed previous reports from Saudi Arabia. We retrospectively examined the records of sputum smear and culture-positive pulmonary tuberculosis patients admitted consecutively from 1998 through 1999 in a main referral hospital in Riyadh, and analyzed drug sensitivity reports. We also reviewed previous reports on antituberculosis drug resistance in Saudi Arabia. Of 515 patients with pulmonary tuberculosis, 80 (15.5%) had resistance to at least one antituberculosis drug. Resistance to streptomycin was most frequent (9.7% ), followed by rifampicin (9.5%), isoniazid (4.3%), and ethambutol (0.2%). Resistance to one antituberculosis drug was found in 8.9%, resistance to two drugs in 5.2%, resistance to three drugs in 1.2%, and resistance to four drugs in 0.2%. Multidrug resistance (defined as resistance to at least isoniazid and rifampicin) was found in 1.9% of patients. A literature review including 6114 patients in Saudi Arabia showed that resistance against streptomycin was most common (8.8%), followed by rifampicin (8%), and isoniazid (7.2%). Of the 6114 patients, 6.8% patients were resistant to only one drug, 3.6% were resistant to two drugs, and 3.7% to three drugs. The high prevalence of rifampicin resistance and resistance to multiple drugs in the Riyadh region and in other parts of Saudi Arabia is a major challenge to the control of tuberculosis in this country. Efforts should be made to prevent the emergence of further antituberculosis drug resistance.

After years of decline tuberculosis has re-emerged as a serious public health problem worldwide. In 1993 the World Health Organization (WHO) declared tuberculosis to be a global emergency and according to a recent WHO report there were 7.96 million new cases in 1997 with 2 million deaths. Factors contributing to the resurgence of tuberculosis include the HIV epidemic immigration of persons from countries with high incidence rates and political turmoil in some developing countries which hinder efforts to control the disease. The spread of the disease poses a public health concern especially with increased drug resistance among M. tuberculosis strains which have acquired varying degrees of resistance to firstline anti-tuberculous drugs. The underlying causes of single drug-resistant M. tuberculosis (SDR-TB) and/or multidrug-resistant M. tuberculosis (MDR-TB) have been suggested to be the result of incorrect treatment poor compliance shortage of anti-tuberculous drugs due to financial constraints in some developing countries and deficient or deteriorating TB control programs resulting in inadequate administration of effective chemotherapy. Previous reports indicate that single-drug resistance and multi-drug resistance to M. tuberculosis are on the increase in both developed and developing countries. The prevalence of SDR-TB or MDR-TB in the Kingdom of Saudi Arabia is largely unknown except for a few studies confined to large centers. The objective of this article is to review published materials from different regions of the Kingdom on the prevalence of SDR-TB and MDR-TB and to draw a conclusion of the actual status of drug-resistant tuberculosis in Saudi Arabia with a discussion of the findings. (excerpt)

Background: The emergence and spread of drug resistant and multidrug resistance are a global health problem. The susceptibility patterns of M. tuberculosis isolates against anti-tuberculosis drugs forms an important aspect of the control programs at the local level. The aim of this study was to determine the pattern of the susceptibility of drugs to M. tuberculosis isolates from patients with pulmonary tuberculosis in Tripoli, Libya. Methods: Drug Susceptibility Test (DST) was performed on 261 isolates of M. tuberculosis by BD BACTEC MGIT 960 SIRE system. The drugs tested were: isoniazid (INH), rifampicin (RIF), streptomycin (SM) and ethambutol (EMB). Results: All isolates (261) were confirmed as M. tuberculosis complex and showed different resistance patterns: 8.8% to INH; 5.7% to RIF; 8.8% to SM; and 9.0% to EMB. Rifampicin was the lowest detected resistance first-line antibiotics studied. One drug resistant was observed in 18.0%; 3.8% were resistant to two drugs; and 2.3% were resistant to a combination of three-drugs. Of the total 261 cases, 217 were designated as new untreated patients and 44 as previously treated patients. In terms of resistance to any drug, there was a significant difference between the two categories (P<0.014). However, there was no significant difference between new and previously treated patients in relation to one drug resistant (P=0.4). Meanwhile, there was a significant difference in relation to two drug resistant (P<0.005), Nine (20.5%) of the isolates designated multi-drug resistant (MDR) were obtained only from previously treated patients. None of newly treated cases had isolates resistant to three-drugs nor MDRs. Conclusion: This preliminary study indicated the low prevalence of drug resistance M. tuberculosis (MTB) among previously treated patients in Tripoli.

ObjectiveThe resistance of Mycobacterium (M.) tuberculosis to antituberculosis drugs poses amajor threat to global public health. Whole genome sequencing (WGS) is an increasingly preferred method in the diagnostics and monitoring of the transmission dynamics of resistant forms of tuberculosis (TB). The aim of the study was to, for the first time, use the sequencing-based analysis to study the transmission and resistance patterns of asystematic and recent collection of extensively drug resistant (XDR) and multidrug resistant tuberculosis (MDR-TB) isolates and to expand our knowledge about drug resistant (DR) TB epidemiological dynamics in Slovakia. DesignAtotal of 495 patients with pulmonary TB, who were referred to National Reference Laboratory for Mycobacteriology (Vyšné Hágy, Slovakia) in the years 2018–2019, were studied. Out of the total of 495 patients, 4 XDR-TB (0.8%) and 8 (1.6%) MDR-TB isolates were identified by conventional drug susceptibility testing on Löwenstein-Jensen solid medium and subjected to whole genome sequencing. Sequencing data were evaluated for molecular-epidemiological analysis and identification of resistance patterns. ResultsPhylogenetic and cluster analysis showed extensive recent transmission events and the predominance of Euro-American lineage 4.7 in Slovakia. However, phylogenetic analysis revealed the circulation of several lineages that originally occurred in Eastern European countries. Resistance patterns for first- and second-line antituberculosis drugs characterized by whole genome sequencing were in high concordance with the results of phenotypic drug susceptibility testing. ConclusionForty percent of at least MDR-TB isolates were not genetically linked, indicating that appropriate measures should be taken to monitor and prevent the spread of drug-resistant tuberculosis within the country as well as in other regions.

Mycobacterium tuberculosis is a highly studied pathogen due to public health importance. Despite this, problems like early drug resistance, diagnostics and treatment success prediction are still not fully resolved. Here, we analyze the incidence of point mutations widely used for drug resistance detection in laboratory practice and conduct comparative analysis of whole-genome sequence (WGS) for clinical M. tuberculosis strains collected from patients with pulmonary tuberculosis (PTB) and extra-pulmonary tuberculosis (XPTB) localization. A total of 72 pulmonary and 73 extrapulmonary microbiologically characterized M. tuberculosis isolates were collected from patients from 2007 to 2014 in Russia. Genomic DNA was used for WGS and obtained data allowed identifying major mutations known to be associated with drug resistance to first-line and second-line antituberculous drugs. In some cases previously described mutations were not identified. Using genome-based phylogenetic analysis we identified M. tuberculosis substrains associated with distinctions in the occurrence in PTB vs. XPTB cases. Phylogenetic analyses did reveal M. tuberculosis genetic substrains associated with TB localization. XPTB was associated with Beijing sublineages Central Asia (Beijing CAO), Central Asia Clade A (Beijing A) and 4.8 groups, while PTB localization was associated with group LAM (4.3). Further, the XPTB strain in some cases showed elevated drug resistance patterns relative to PTB isolates. HIV was significantly associated with the development of XPTB in the Beijing B0/W148 group and among unclustered Beijing isolates.

Detection of drug resistance in Mycobacterium tuberculosis.

Objective To analyze the characteristics of second-line anti-tuberculosis (TB) drugs resistance and gene mutation of multidrug-resistant (MDR) Mycobacterium tuberculosis isolated in Ningbo. Methods In 1597 M. tuberculosis isolates collected in the first drug resistance survey in Ningbo between 2018 and 2019, 133 MDR isolates, including 31 isolated from elderly group and 102 isolated from young and middle age group, were used in the study. All the isolates were detected using RD105 deletion-targeted multiplex PCR for Beijing genotype identification. Gene sequencing with PCR was conducted to detect the mutations of rrs, tlyA, eis, gidB, gyrA and gyrB genes. The conventional drug susceptibility test was used to detect the resistances to 5 second-line anti TB drugs (kanamycin, amikacin, capreomycin, ofloxacin, levofloxacin). Results The multidrug resistance rate of M. tuberculosis isolates was 8.33% (133/1597) in Ningbo. The resistance rates of 133 MDR M. tuberculosis isolates to kanamycin, amikacin, capreomycin, ofloxacin and levofloxacin were 7.52% (10/133), 6.01% (8/133), 3.01% (4/133), 30.08% (40/133) and 29.32% (39/133). The rates of Pre-XDR and XDR of 133 MDR M. tuberculosis isolates were 28.57% (38/133) and 6.01% (8/133). The gene mutation rates of rrs, tlyA, eis, gidB, gyrA and gyrB of 133 MDR M. tuberculosis isolates were 6.77% (9/133), 7.52% (10/133), 1.50% (2/133), 3.76% (5/133), 34.59% (46/133) and 3.01% (4/133). There were 2 rrs mutations, 1 tlyA mutation, 2 eis mutations, 2 gidB mutations, 5 gyrA mutations and 4 gyrB mutations. Single base substitution was the main type. Conclusion The resistance of MDR M. tuberculosis to second-line anti-TB drugs was serious in Ningbo, especially the resistance to fluoroquinolone. It is necessary to strengthen the prevention and control of second-line anti TB drugs resistances of MDR M. tuberculosis.

Introduction The HIV/AIDS pandemic has led to a rise in the incidence of tuberculosis and an epidemic of co-infection in many developing countries. Treatment of Mycobacterium tuberculosis in persons with HIV infection presents several challenges to the clinician, particularly in resource-poor countries. As will be discussed in this paper, diagnosis of latent tuberculosis relies on tuberculin skin testing, which has poor sensitivity and reproducibility in immunocompromised patients. The World Health Organization (WHO) recommends treatment of active tuberculosis as the primary means of global tuberculosis control. In practice, treatment of active tuberculosis typically requires that a symptomatic patient self-report to a health service for evaluation and management. Even if this approach to tuberculosis control were sufficient, many logistic and clinical problems remain involving tuberculosis diagnosis and therapy in the patient with HIV/AIDS. Recognizing the significant clinical and public health challenges surrounding the treatment of tuberculosis in patients with HIV infection, this paper will address a number of issues relevant to the care of co-infected patients. These include current guidelines for the treatment of active tuberculosis, as well as the diagnosis and treatment of latent tuberculosis in HIV-positive patients. The paper concludes with a discussion of promising new drugs for tuberculosis treatment. Epidemiology of tuberculosis and HIV co-infection It is estimated that one-third of the world population is infected with M. tuberculosis, the large majority of whom live in the developing world. The HIV pandemic of the past two decades has led to a rise in the incidence of tuberculosis, particularly in sub-Saharan Africa. There is now an emerging pandemic of patients with HIV infection who are co-infected with tuberculosis. As of December 2000, the WHO estimated that approximately 36.1 million persons worldwide are living with HIV and nearly one-third of these persons are co-infected with M. tuberculosis[1]. Approximately 68% of persons co-infected with HIV and tuberculosis live in sub-Saharan Africa, while 22% live in Southeast Asia. In the United States, the Centers for Disease Control and Prevention (CDC) estimates that approximately 40% of new tuberculosis cases among persons aged 15-44 years occur among individuals with HIV infection or AIDS. Tuberculosis rates among HIV-infected individuals in the United States, however, vary significantly among different groups, with highest rates among intravenous drug users and those who are foreign-born. Today, the burden of tuberculosis and HIV infections largely impacts the developing world, as well as the minority and low socio-economic individuals within industrialized countries. This paper will discuss issues in the treatment of M. tuberculosis in patients with HIV/AIDS; however, it is important to recognize that many patients co-infected with HIV and M. tuberculosis have limited or no access to essential diagnostic and therapeutic strategies. Escalating tuberculosis case rates over the past decade are largely attributable to HIV. Immunity to M. tuberculosis is partly under the control of the MHC class II restricted CD4 cells. With the progressive loss of CD4 cells, patients with HIV infection are at increased risk of reactivation of latent tuberculosis, as well as primary tuberculosis infection [2]. In turn, active tuberculosis infection appears to upregulate HIV replication, resulting in further immune compromise and accelerated HIV disease progression [3,4]. As a result, patients with HIV infection and active tuberculosis are at increased risk of opportunistic infections and associated mortality. The case fatality rate by the end of tuberculosis treatment is approximately 20% for new sputum smear-positive cases and up to 50% for new smear-negative cases [5]. Tuberculosis is the leading cause of death among persons with HIV/AIDS worldwide [6]. Guidelines for the treatment of active tuberculosis This section will review recent guidelines for the treatment of tuberculosis published by the Tuberculosis Committee of the Infectious Disease Society of America (IDSA) in conjunction with the American Thoracic Society (ATS) and the CDC [7,8]. In addition, we will review the Directly Observed Treatment Short-course (DOTS) strategy of the WHO for tuberculosis control worldwide. These published guidelines pertain to the treatment of tuberculosis without respect to the patient's HIV status. Modified recommendations for the treatment of tuberculosis in HIV-seropositive patients will be discussed in the following section. In April 2000, the IDSA published practice guidelines for the treatment of tuberculosis [7]. Table 1, adapted from the IDSA publication, lists the 10 essential recommendations for the treatment of patients with tuberculosis. Readers are referred to the original publication for detailed comments pertaining to these recommendations, as well as performance indicators. It should be noted that the IDSA recommendations were developed for use in industrialized nations such as the United States and are currently not feasible in many countries of the world. In Table 1, therefore, we have juxtaposed the WHO DOTS strategy guidelines for management of patients with tuberculosis.Table 1: Infectious Disease Society of America (IDSA) recommendations and World Health Organization Directly Observed Treatment Shortcourse (WHO DOTS) strategy for the management of patients with tuberculosis (TB).In geographic areas where ≥ 4% of the M. tuberculosis isolates are resistant to isoniazid, the IDSA, ATS, and CDC recommend that the usual three-drug regimen of isoniazid, rifampin and pyrazinamide be augmented with a fourth drug, either ethambutol or streptomycin. Clinicians will therefore need to be aware of the susceptibility patterns in their geographic area. In 1997, approximately 84% of the US population lived in states that had ≥ 4% of tuberculosis isolates resistant to isoniazid. Therefore, most patients in the United States should be started on an initial four-drug regimen. This is followed by isoniazid and rifampin for 18 weeks. Although a 6-month course of treatment is recommended, this should be extended to 9 months if there is a delay in AFB, culture conversion or clinical improvement for 8 weeks. The WHO Global Tuberculosis Programme (WHO/GTP) assists over 60 countries with national tuberculosis control and prevention. The priority of the WHO program has been active case finding and cure of infectious tuberculosis cases. In 1993, the WHO/GTP declared tuberculosis a global emergency and began promoting the DOTS strategy. The DOTS strategy consists of five key components: "1) Government commitment to sustained TB control activities; 2) Case detection by sputum smear microscopy among symptomatic patients self-reporting to health services; 3) Standardized treatment regimen of six to eight months for at least all confirmed sputum smear positive cases, with directly observed treatment (DOT) for at least the initial two months; 4) A regular, uninterrupted supply of all essential anti-tuberculosis drugs; and 5) A standardized recording and reporting system that allows assessment of treatment results for each patient and of the TB control programme performance overall" [9] (see Table 1). According to the WHO/GTP, as of 1999, 127 countries had accepted the DOTS strategy and were implementing it to varying degrees [10]. Nevertheless, the WHO/GTP estimate that, in 1999, only 45% of the world population had access to DOTS and 23% of new smear-positive cases were referred to DOTS programs. In addition, there are often a complex array of political, financial, and infrastructure problems that impede local DOTS programs. The current WHO DOTS strategy does not incorporate the diagnosis and treatment of latent tuberculosis. Some experts believe that the DOTS strategy, which focuses exclusively on the treatment of active cases, is insufficient for the control and elimination of tuberculosis, particularly in the HIV/AIDS era [11]. It has been recommended that targeted diagnosis and treatment of latent tuberculosis infection among specific populations be added to national tuberculosis control programs. At present, WHO recommends treatment of latent tuberculosis in HIV-positive patients; but only in settings where it is possible to provide HIV testing and counseling, and where it is possible to exclude cases of active tuberculosis and ensure proper follow-up. The DOTS strategy also employs empiric anti-tuberculous therapy without mycobacterial cultures and drug susceptibility testing. Without drug susceptibility information, it is impossible to identify cases of drug-resistant tuberculosis and to avoid treatment failure and further transmission of drug-resistant strains. The WHO recognizes the threat of multidrug-resistant tuberculosis (MDR-TB) and, in July 1999, convened a working group on DOTS-Plus for the treatment of MDR-TB [12]. DOTS-Plus is a pilot program to provide second-line drugs (i.e., fluoroquinolones, amikacin, kanamycin, capreomycin, cycloserine, para-aminosalicylic acid, and ethionamide) to manage MDR-TB in resource-limited countries. This strategy does not, however, address the role of mycobacterial cultures and drug susceptibility testing for individualized drug therapy and the prevention of drug-resistant tuberculosis. Finally, because DOTS relies on patients self-reporting to health services, additional tuberculosis transmission can take place before the patient is evaluated and receives appropriate therapy. Modeling of the tuberculosis epidemic in Tanzania suggests that DOTS may slow the incidence rate, but in the face of the HIV epidemic is unlikely to reverse the upward trend [13]. Again, some experts advocate targeted case finding, particularly among high-risk groups [11,14]. Diagnosis and treatment of active tuberculosis infection in patients with HIV infection This section deals specifically with the treatment of active tuberculosis in HIV-infected individuals as recommended by the CDC [15,16]. Again, many people co-infected with HIV and tuberculosis in the developing world do not have access to the relevant diagnostic tests and anti-tuberculosis and antiretroviral therapies. To impact tuberculosis-associated morbidity and mortality worldwide, developing countries will require both the skills and commodities to diagnose and treat individuals effectively. At present, tuberculosis treatment for the HIV-positive patient as recommended by the CDC is not applicable in most resource-poor countries. Treatment of active and latent tuberculosis infection in patients with HIV depends on the application of both clinical judgment and appropriate diagnostic tests. Active tuberculosis can occur at any CD4 cell count but atypical presentations are more likely with advanced HIV disease or AIDS. Clinicians should be alert to the sometimes atypical presentations of pulmonary and extrapulmonary tuberculosis in HIV-infected patients. Sputum acid fast staining, mycobacterial cultures, and drug susceptibility testing are recommended in all patients suspected of having tuberculosis. However, patients with HIV are slightly less likely to have positive sputum smears than non-HIV-infected individuals [17]. Likewise, chest radiographic findings can vary depending on the degree of immunosuppression. Patients with CD4 cell counts greater than 200 are more likely to have classic findings of upper lobe infiltrates with cavitary lesions, while those patients with AIDS may more likely have hilar adenopathy and pleural effusions without cavitations [18]. Mycobacteremia and extrapulmonary tuberculosis, especially meningitis and adenopathy, also correlate with diminishing numbers of CD4 cells and degree of immunosuppression. Thus, for patients with HIV infection, the diagnosis of active tuberculosis is more challenging. Clinical suspicion of tuberculosis in a patient known or suspected of being HIV-infected should result in prompt initiation of anti-tuberculosis therapy regardless of sputum staining or radiograph findings. The 1998 CDC recommendations for the treatment of tuberculosis among patients infected with HIV are summarized in Table 2[15]. The treatment of tuberculosis in the HIV-seropositive patient may differ from the standard treatment in the following ways: (i) choice of anti-tubercular regimen and dose adjustments; (ii) duration of treatment (ideally with directly observed therapy); (iii) promotion of antiretroviral therapy; and (iv) monitoring requirements. Due to rapid advances in the management of HIV disease, it is recommended that all patients co-infected with HIV and tuberculosis should be evaluated by a specialist to ensure optimal management.Table 2: Tuberculosis (TB) treatment recommendations for the HIV-seropositive patient.The treatment algorithm begins with establishing the patient's HIV status and whether the patient is on optimal antiretroviral therapy. All patients diagnosed with active tuberculosis should be HIV tested and, if seropositive, evaluated for antiretroviral therapy. It was previously felt that the diagnosis of active tuberculosis should result in the deferral of antiretroviral therapy. Early initiation of antiretroviral therapy is now recommended. While being treated for tuberculosis, the HIV-positive patient not receiving concurrent HIV therapy should be reassessed every 3 months for initiation of antiretroviral therapy. Known or suspected HIV-positive patients should receive prompt initiation of effective anti-tuberculosis therapy. If antiretroviral therapy is not started, the patient can typically receive standard anti-tuberculosis therapy: isoniazid, rifampin, pyrazinamide, and ethambutol. If the patient is to receive simultaneous anti-tuberculosis and antiretroviral therapy, the selected regimens and doses must account for significant drug-drug interactions between the rifamycins (rifampin, rifabutin, rifapentine) and the protease inhibitors and non-nucleoside reverse transcriptase inhibitors (NNRTI). Rifamycins, particularly rifampin, induce the hepatic cytochrome P-450 (CYP450) and reduce the serum levels of protease inhibitors, NNRTI, and other drugs metabolized by the CYP450 system. The CDC generally recommends the substitution of rifabutin, a less potent CYP450 inducer, for rifampin to allow simultaneous use of protease inhibitors and NNRTI. The use of rifampin with protease inhibitors or NNRTI is contraindicated, except in three antiretroviral combinations: (i) the NNRTI efavirenz and two nucleoside reverse transcriptase inhibitors (NRTI); (ii) the protease inhibitor ritonavir and one or more NRTI; and (iii) the combination of ritonavir and saquinavir, either hard-gel or soft-gel capsules [16]. Table 3 lists the recommended anti-tubercular drug doses, depending on frequency of administration and concurrent antiretroviral use.Table 3: Anti-tubercular drug doses.If the HIV-positive patient is already on an effective anti-retroviral regimen at the time of tuberculosis diagnosis, it is desirable to continue the patient on the same antiretroviral regimen with appropriate dose adjustments. If the patient is starting a new antiretroviral regimen, options include: (i) a rifabutin-based regimen with the necessary protease inhibitor or NNRTI dose adjustments; (ii) a non-rifamycin-containing regimen such as isoniazid, streptomycin, pyrazinamide, ethambutol for 2 months, then isoniazid, streptomycin, ethambutol for 7 months; or (iii) a regimen that does not contain a protease inhibitor or NNRTI. Table 4 lists the recommended dose adjustments for rifabutin-based regimens. Given the complexity of these drug interactions, it is recommended that the selection of dual anti-tubercular and antiretroviral therapies be made following consultation with a specialist.Table 4: Protease inhibitor (PI) or non-nucleoside reverse transcriptase inhibitor (NNRTI) dose adjustments with rifabutin.Among the protease inhibitors, ritonavir has the highest potency in inhibiting the CYP450 pathway. With any dose of ritonavir, including low-dose ritonavir 100 mg twice a day, a reduced dose of rifabutin (150 mg two or three times per week) is recommended. According to the 2000 CDC guidelines for the use of rifabutin or rifampin among patients taking protease inhibitors or NNRTI, co-administration of ritonavir with the usual dose of rifampin (600 mg daily or two or three times per week) may be an option but pharmokinetic and clinical data are limited [16]. As previously stated, a patient taking the combination of saquinavir (either the soft-gel or hard-gel capsule) and ritonavir should take the reduced dose of rifabutin (150 mg two or three times per week). The saquinavir-ritonavir combination may possibly be given with the usual dose of rifampin but, again, limited pharmacokinetic and clinical data are available. Saquinavir, as a sole protease inhibitor, is generally not recommended in combination with rifabutin because the serum levels of saquinavir may be decreased as much as 45%. Indinavir, nelfinavir, and amprenavir should not be used in combination with rifampin, but all three protease inhibitors can be administered with a reduced daily dose of rifabutin (150 mg daily) or the usual dose of rifabutin (300 mg two or three times per week). Efavirenz induces CYP450 and accelerates rifamycin metabolism; therefore, efavirenz should be co-administered with an increased dose of rifabutin (450 or 600 mg daily, or 600 mg two or three times per week). According to the recent CDC guidelines, efavirenz may be combined with the usual dose of rifampin (600 mg daily or two or three times per week). The NNRTI nevirapine should typically be given with the usual dose of rifabutin (300 mg daily or two or three times per week). If co-administration of nevirapine with rifampin is clearly indicated, careful monitoring is recommended. The use of delavirdine is contraindicated during the treatment of tuberculosis because the drug levels are markedly decreased with both rifampin and rifabutin. HIV-infected patients have a higher incidence of drug-resistant tuberculosis isolates than non-HIV-infected patients. There have been several reports of increased risk of rifampin resistance among HIV-positive patients [19-21]. Higher rates of drug-resistant tuberculosis in HIV-infected patients may be associated with biological, behavioral, and societal factors including drug malabsorption, non-adherence, nosocomial outbreaks, and inadequate drug therapy in countries with high rates of co-infection. Directly observed therapy, regarded as the best strategy for ensuring adherence and limiting drug-resistant tuberculosis, is recommended for all patients with HIV infection [15]. In a randomized, controlled trial of anti-tuberculosis therapy among HIV-positive patients in Baltimore, Maryland, patients who received supervised therapy for tuberculosis had better survival than those who self-administered therapy [22]. Treatment of drug-resistant tuberculosis involves initiation of a multi-drug regimen tailored to the susceptibility profile of the organism. Due to the diversity of resistance patterns, it is not possible to recommend standardized protocols for therapy. Any regimen should include two or more drugs to which the isolate is susceptible. For HIV-positive patients at risk of MDR-TB, defined as resistance to both isoniazid and rifampin, initial empiric treatment should include second-line tuberculosis drugs to which resistance is uncommon. The 1999 WHO Essential Drug List was to include the following second-line tuberculosis amikacin, kanamycin, capreomycin, cycloserine, acid, and and drug susceptibility testing should be on all tuberculosis isolates and the anti-tuberculosis regimens Although MDR-TB is associated with a high mortality rate especially in resource-poor countries where the detection of drug resistance to months, if at and the second-line drugs are often months is the duration of treatment for pulmonary tuberculosis among HIV-positive patients in the United States a regimen is used [15]. treatment is for patients with a clinical or conversion of sputum cultures from positive to Some experts recommend the use of treatment regimens in all patients with HIV infection, especially among patients with advanced [17]. duration of treatment is clearly recommended in patients with slow clinical or with or HIV-positive individuals with active tuberculosis to be at increased risk of tuberculosis of a 6-month regimen. A trial of isoniazid was among HIV-positive patients in who a 6-month regimen of isoniazid decreased the risk of a of tuberculosis among HIV-positive patients. This not whether these were to M. tuberculosis or both of which have previously been The recommend of isoniazid for HIV-positive patients of tuberculosis therapy. At present, the WHO and the CDC recommend a months of directly observed tuberculosis therapy without Treatment of latent tuberculosis infection in patients with HIV infection It is estimated that 2 people worldwide are infected with latent tuberculosis. Patients with HIV infection are at increased risk of to active disease [2]. In 2000, the and the CDC new guidelines for the diagnosis and treatment of latent tuberculosis infection This public health strategy both prevention by the latent infection before it to active infection and primary prevention by further tuberculosis In addition, the use of active antiretroviral therapy has been to reduce the incidence of tuberculosis among persons with HIV infection The new guidelines recommend targeted of populations and patients at increased risk of tuberculosis infection who from treatment to active for targeted include drug health care of and all patients with HIV Diagnosis of latent tuberculosis infection is on the tuberculin skin new including detection are being developed A has with tuberculin skin testing in are to the diagnostic of this in the United States and in populations with varying degrees of risk for latent tuberculosis. There be two significant of developing tests for the detection of latent M. tuberculosis tests the need for a health service at and their be less than tuberculin skin testing. of latent tuberculosis in an HIV-infected patient can be a diagnostic It has been that the sensitivity of tuberculin skin testing may be in patients with to as well as to and can in persons with HIV infection and of the is associated with higher CD4 cell For these testing is no recommended for the diagnosis of latent tuberculosis. guidelines are to treat latent tuberculosis infection in HIV-infected persons with at high-risk of latent tuberculosis or with recent to a case of active tuberculosis should receive therapy regardless of tuberculin has been the of treatment of latent tuberculosis clinical have a in the risk of to active tuberculosis following months of isoniazid therapy. The optimal duration of isoniazid therapy has also been including the trial of the Tuberculosis and in in the and this or months of isoniazid therapy months of isoniazid therapy reduced the tuberculosis incidence by with for months and 20% for 3 months; however, with months therapy was than for of therapy A recent of isoniazid therapy in that from isoniazid therapy 9 months, with no additional associated with therapy The new and CDC guidelines recommend isoniazid therapy for 9 months (300 mg isoniazid daily mg with months of therapy as a less The to isoniazid therapy include and poor Directly observed therapy has been to adherence but is not important in the treatment of latent tuberculosis has been the of regimens that may adherence and reduce have the of regimens for the treatment of latent tuberculosis in individuals A trial that daily rifampin and pyrazinamide for 2 months was to isoniazid for months for the treatment of latent tuberculosis in HIV-infected persons the of these the new guidelines regimens for the treatment of latent tuberculosis as summarized in Table from their publication rifampin and pyrazinamide for 2 months (600 mg rifampin daily pyrazinamide daily) is the regimen for HIV-infected patients and be for suspected cases of tuberculosis. should be for rifampin in patients receiving protease inhibitors or NNRTI, further is to in the treatment of latent tuberculosis. The same drug-drug interactions and dose adjustments for antiretroviral drugs and rifamycins It is that the also recommends the regimen for individuals the the clinical for this combination have been only in HIV-positive patients. If MDR-TB is the recommended therapy is pyrazinamide and ethambutol or pyrazinamide and a (i.e., or for Treatment for suspected to MDR-TB should be extended to months for HIV-positive American Thoracic Society and Centers for Disease Control and Prevention guidelines for the treatment of latent tuberculosis the use of rifampin pyrazinamide therapy in infected patients has been associated with a rate of patients with resulting from the use of therapy have been to the five of these patients on these CDC and have their 2000 recommendations The (i) that be used with particularly in patients with disease, on or those taking drugs; and (ii) that patients who are treated with be by a health care at and for a of tests and evaluation with a at 8 to treatment therapy with the regimen should be for significant rates of have not been observed in HIV-infected patients treated with this regimen, either in clinical or to the use of the regimen in For HIV-infected patients to persons with active tuberculosis, treatment for latent tuberculosis should be a tuberculin In addition, some experts advocate HIV-infected individuals who in high-risk evaluation for latent tuberculosis treatment should include a careful and and, chest radiograph to exclude active tuberculosis. anti-tubercular drugs in treatment of tuberculosis, particularly for MDR-TB, will on the of new anti-tubercular there are several drugs under that have in M. tuberculosis. In some cases the drug has also in a of tuberculosis, and some have received and Drug for other under include and other and is a rifamycin the serum of which is three times than that of the rifampin The of M. tuberculosis is to or one to that of Given the between and other rifamycin the of over rifampin pharmokinetic In the infected with tuberculosis and in tuberculosis a regimen is less active than a daily regimen, both rifamycins being given at 10 In tuberculosis however, the regimen is significantly less active than the daily regimen In the regimens during the of tuberculosis therapy may provide increased to as well as to health care programs. is an for and other infections that has in M. tuberculosis, to that of and in in a of tuberculosis that at 100 is as as isoniazid at and more than clinical are being to the role of in combination therapy active tuberculosis. and also promising in a of tuberculosis are a class of inhibitors with and The of at 100 is with isoniazid at per an by the and Drug for the treatment of appears to be less active M. tuberculosis than It has been recommended, however, for further at higher is a new to that has been to potent in M. in were also to be to this with of In a administration of this drug at a dose of per led to of disease burden in and with that with isoniazid per and issues in the treatment of tuberculosis in patients with HIV have previously to some of the and issues that the treatment of tuberculosis in resource-poor countries. At the and there may also some important and to effective tuberculosis treatment. A among tuberculosis patients in Tanzania that only of the patients had of the disease and treatment In a recent from people were generally well HIV but tuberculosis of and were to AIDS than tuberculosis. patients with tuberculosis were often as having AIDS. Due to the associated with the that patients with tuberculosis may not or to appropriate These the important impact that the HIV epidemic may have on the public and to tuberculosis. a epidemic of tuberculosis and HIV co-infection in many of the developing world. The increased of tuberculosis and HIV/AIDS and the rise of MDR-TB a health threat to all While significant have been made in developing regimens for the treatment of active and latent tuberculosis, therapy is and second-line drugs are drug resistance is for are the anti-tuberculosis of drugs such as and and the of which may treatment. The optimal use of these drugs in combination therapy is a promising of active In addition, we advocate the of new and tuberculosis drugs that will be made to patients in developing countries.

Isoxyl (ISO) and thiacetazone (TAC), two prodrugs once used in the clinical treatment of tuberculosis, have long been thought to abolish Mycobacterium tuberculosis (M. tuberculosis) growth through the inhibition of mycolic acid biosynthesis, but their respective targets in this pathway have remained elusive. Here we show that treating M. tuberculosis with ISO or TAC results in both cases in the accumulation of 3-hydroxy C(18), C(20), and C(22) fatty acids, suggestive of an inhibition of the dehydratase step of the fatty-acid synthase type II elongation cycle. Consistently, overexpression of the essential hadABC genes encoding the (3R)-hydroxyacyl-acyl carrier protein dehydratases resulted in more than a 16- and 80-fold increase in the resistance of M. tuberculosis to ISO and TAC, respectively. A missense mutation in the hadA gene of spontaneous ISO- and TAC-resistant mutants was sufficient to confer upon M. tuberculosis high level resistance to both drugs. Other mutations found in hypersusceptible or resistant M. tuberculosis and Mycobacterium kansasii isolates mapped to hadC. Mutations affecting the non-essential mycolic acid methyltransferases MmaA4 and MmaA2 were also found in M. tuberculosis spontaneous ISO- and TAC-resistant mutants. That MmaA4, at least, participates in the activation of the two prodrugs as proposed earlier is not supported by our biochemical evidence. Instead and in light of the known interactions of both MmaA4 and MmaA2 with HadAB and HadBC, we propose that mutations affecting these enzymes may impact the binding of ISO and TAC to the dehydratases.

Study Background: Drug resistance in Mycobacterium tuberculosis is a serious problem all over the world. One of the major factors contributing to drug resistance is delayed detection of drug-resistant isolates, which ultimately leads to delay in initiation of effective chemotherapy. An appropriate modification of treatment regimens, depending upon the susceptibility pattern of Mycobacterium isolates is the keystone for successful treatment of drug-resistant tuberculosis. Material and methods: The study was done to check the susceptibility pattern of both pulmonary and extrapulmonary isolates of Mycobacterium tuberculosis during Aug 2009 - Jun 2012, Phase II (35 month period) and compared it with our previous data of same duration (Aug 2002-Jun 2005, Phase I), to determine the burden of drug resistance in the current situation and to look for the change in resistance pattern over a decade. A total of 154 culture-confirmed Mycobacterium tuberculosis isolates (pulmonary-36, extra-pulmonary-118) were screened for their susceptibility pattern. Drug susceptibility testing was performed by an automated Bac T-Alert 3D, using ‘SIRE’ kit’ provided with Bact Alert 3D system (Biomereiux Pvt Ltd). Result: Current study demonstrated increased drug resistance for streptomycin, isoniazid, rifampicin and ethambutol as 8/36 (22.2%), 23/36 (63.8%), 6/36 (16.6%) and 21/36 (33.3%) respectively in the pulmonary isolates and 39/118 (33%), 71/118 (60.1%), 16/118 (13.5%) and 60/118 (50.8%) among the extra-pulmonary isolates. A significant increase in resistance (p value=0.0001) was observed for streptomycin in current phase as compared with the earlier phase of study while resistance to rifampicin was decreased in pulmonary isolates. However, resistance to streptomycin, isoniazid and ethambutol were significantly increased (p value=0.0001) among extrapulmonary isolates. Conclusion: Resistance to streptomycin has increased at an alarming rate in pulmonary tuberculosis (TB). However, resistance to isoniazid and rifampicin has stabilized over time, this could possibly imply adequacy of DOTS coverage in cases of pulmonary TB. This situation in patients with extra-pulmonary TB is more alarming as this data reveals a dramatic increase of resistance to isoniazid and other first-line agents. The “hidden reservoir” of resistance in extra-pulmonary patients may downgrade the efficacy of the DOTS program in the future.

BackgroundThe spread of multidrug-resistant tuberculosis (MDR-TB) strains has become a challenge to the global TB control and prevention program. In Ethiopia, particularly in rural areas, information on drug-resistant TB is very limited. In this study, we determined the drug resistance patterns of Mycobacterium tuberculosis (M. tuberculosis) isolates from pulmonary TB patients attending two public hospitals in the East Gojjam zone of northwest Ethiopia.MethodsA cross-sectional study was conducted between May 2011 and January 2012 using Region of difference-9 (RD9) typing for the identification of species mycobacterium. Drug susceptibility testing (DST) of M. tuberculosis isolates to the first-line drugs: isoniazid, rifampicin, ethambutol and streptomycin was performed by the indirect proportion method on Middle brook 7H10 Agar media.ResultsOut of 385 pulmonary TB suspects studied, 124 (32.2 %) were culture positive among which 120 were M. tuberculosis strains. Susceptibility testing was performed for 89 isolates. Resistance to at least one drug was 15.58 % ([12/77], 95 % CI: 7.48-23.68) among newly diagnosed and 50.0 % ([6/12], 95 % CI: 21.71-78.29) among previously treated cases. Resistance among newly diagnosed patients was most common for streptomycin 5.19 % (4/77) and ethambutol 5.19 % (4/77) followed by rifampicin 3.89 % (3/77). Among retreatment cases, isoniazid resistance was most frequent in which 33.33 % (4/12) of the isolates were resistant. MDR prevalence was 1.29 % (1/77) for newly diagnosed and 16.67 % (2/12) for retreatment cases. In a multivariate logistic regression analysis, age group of 25–34 years (adjusted OR = 4.24; 95 % CI: 1.02-17.5; P = 0.046) and previous history of treatment (adjusted OR = 5.42; 95 % CI: 1.56-27.49; P = 0.01) were independently associated with anti-TB drug resistance.ConclusionsIn general, the magnitude of anti-TB drug resistance including MDR-TB was comparable to previous studies in other areas of Ethiopia. However, rifampicin resistance was high, which could suggest the potential for a rise in the incidence of MDR. Therefore, re-enforcing TB control programs should be considered by the concerned public health authorities.

Spinal tuberculosis (STB), which is the most frequent and serious form of skeletal TB, is seriously harmful to a patient's life. However, very little research has been conducted on clinical isolates of STB. The purpose of this study was to genotype clinical isolates of Mycobacterium tuberculosis (MTB) from patients with STB, investigate their drug resistance profiles, and determine whether the genotypes and drug resistance patterns share any relationships with the demographic and clinical features of the patients. Preliminary species identification of the MTB strains was performed using a TCH/PNB culture method and multilocus polymerase chain reactions. Of the specimens collected from 85 hospital in-patients with STB at Xiangya Hospital, China, the 56 culture-positive MTB strains we identified were genotyped by spoligotyping. The strains were tested for resistance to anti-tuberculosis drugs (ATDs), and the demographic and clinical features of the patients were analyzed in combination with the genotyping and drug resistance results. Of the 56, cases, 53 involved M. tuberculosis and 3 involved M. bovis. Spoligotyping revealed 27 Beijing-type cases and 29 nonBeijing cases. When patients with STB were relapsing or experiencing systemic toxicity signs/symptoms (STS), the Beijing MTB-type strains predominated (p < 0.05), but when the patients were receiving initial treatment or lacked STS, the nonBeijing type MTB strains dominated. The Beijing and nonBeijing types differed in their resistance patterns to 8 ATDs, and the resistance rate of the Beijing type was higher than that of the nonBeijing type (p < 0.05). The bacteriological features of STB, including genotype and drug resistance, shared close relationships with the clinical features of patients with STB. Our data provide a reference for the diagnosis and treatment of STB.

We used large sequence polymorphisms to determine the genotypes of 397 isolates of Mycobacterium tuberculosis from human immunodeficiency virus-uninfected Vietnamese adults with pulmonary (n = 235) or meningeal (n = 162) tuberculosis. We compared the pretreatment radiographic appearances of pulmonary tuberculosis and the presentation, response to treatment, and outcome of tuberculous meningitis between the genotypes. Multivariate analysis identified variables independently associated with genotype and outcome. A higher proportion of adults with pulmonary tuberculosis caused by the Euro-American genotype had consolidation on chest X-ray than was the case with disease caused by other genotypes (P = 0.006). Multivariate analysis revealed that meningitis caused by the East Asian/Beijing genotype was independently associated with a shorter duration of illness before presentation and fewer cerebrospinal fluid (CSF) leukocytes. Older age, fewer CSF leukocytes, and the presence of hemiplegia (but not strain lineage) were independently associated with death or severe disability, although the East Asian/Beijing genotype was strongly associated with drug-resistant tuberculosis. The genotype of M. tuberculosis influenced the presenting features of pulmonary and meningeal tuberculosis. The association between the East Asian/Beijing lineage and disease progression and CSF leukocyte count suggests the lineage may alter the presentation of meningitis by influencing the intracerebral inflammatory response. In addition, increased drug resistance among bacteria of the East Asian/Beijing lineage might influence the response to treatment. This study suggests the genetic diversity of M. tuberculosis has important clinical consequences.

BACKGROUND: Tuberculosis (TB) disease is an infection caused by Mycobacterium tuberculosis and is transmitted through sputum droplets of sufferers or suspect TB in the air. Chitosan as an antimicrobial agent can be used in the biomedical field because it has a number of hydroxyl groups (OH) and amine groups (NH2). The chemical substance of durian peel extract (Durio zibethinus L.) contains pectin which is multifunctional and can be used in the pharmaceutical field. Chemically, pectin is a polysaccharide polymer of D-galacturonic acid linked by -1,4 glycosidic bonds which can dissolve in water to form colloidal solutions or gels. AIM: This study was to determine the antimicrobial effectiveness of chitosan and polysaccharides from durian peel extract (D. zibethinus L.) against M. tuberculosis isolates in vitro. METHODS: The research method is based on an experimental study in vitro. M. tuberculosis isolates in this research from sputum samples of patients suspected of TB in Surakarta Regional General Hospital. The stages of the research were performed that preparation chitosan gel (CG), bioformulation of CG, and polysaccharide gel (PG) durian peel extract are 5%, 10%, 15%, 20%, and 25%, and drug susceptibility testing against M. tuberculosis isolates. RESULTS: CG 10% was effective as an antimicrobial against M. tuberculosis isolates but PG durian peel extract (5%; 10%; 15%; 20%; and 25%) was not effective as an antimicrobial against M. tuberculosis isolates. The types of anti-tuberculosis drug (ATD) that was effective against M. tuberculosis isolates were ethambutol 80% and streptomycin 40%, while isoniazid and rifampicin were not effective as ATD against M. tuberculosis isolates. CONCLUSION: CG 10% was effective as an antimicrobial against M. tuberculosis isolates, while PG 25% durian peel extract was not effective as an antimicrobial against M. tuberculosis isolates. CG has the potential as an ATD based on natural bioactive ingredients for TB therapy.

Characterization of Mycobacterium tuberculosis isolated from cancer patients with suspected tuberculosis infection in Egypt: identification, prevalence, risk factors and resistance pattern