Primary Drug Resistance and Molecular Epidemiology ofMycobacterium tuberculosisIsolates from Patients in a Population with High Tuberculosis Incidence in Turkey

Epidemiology of multidrug-resistant, extensively drug resistant, and totally drug resistant tuberculosis in Middle East countries

The 2015 represent the deadline for the global tuberculosis (TB) targets set through the Millennium Development Goals (MDG). From 2016 and onward, new goals were set to end the global TB epidemic via implementing new campaign entitled "the End TB Strategy". The major hurdle to end TB epidemic in several parts of the world is the emergence and spread of drug resistant Mycobacterium tuberculosis (MTB) strains. The better understanding of the actual global burden of drug resistant tuberculosis would feed into better implementing the End TB Strategy. In this article we summarize the current knowledge on the patterns of drug resistance tuberculosis cases in the Middle East countries. These countries are served by the Eastern Mediterranean Regional Office (EMRO), one out of six regional offices of World Health Organization. Middle East countries are characterized by geographic vicinity and population's interaction. However, they are dissimilar in several aspects such as economy and health infrastructures. Regarding economy, countries in this region are ranging from wealthy to very poor. Prevalence of tuberculosis and patterns drug resistance tuberculosis cases are also following variable trends within countries of this region. In almost all Middle East countries, there is under-reporting of drug-resistance tuberculosis cases. There are shortages in the infrastructures and facilities for detecting the pattern of drug-resistance tuberculosis. For instance, sixout of 14 countries have neither in-country capacity nor a linkage with a partner laboratory for second-line drug susceptibility testing and only 4 countries have registered site performing Xpert MTB/RIF.

Integration of Mycobacterium tuberculosis drug susceptibility testing and genotyping with epidemiological data analysis to gain insight into the epidemiology of drug-resistant tuberculosis in Malatya, Turkey

Drug-resistant tuberculosis (TB) presents a major challenge to global TB control. To gain a better understanding of drug-resistant TB epidemiology in Malatya, Turkey, we conducted the present study using 397 Mycobacterium tuberculosis clinical isolates collected from Malatya, Turkey, in recent years (2000-2007). Resistance to any anti-TB drug was found in 29% (114 of 397) of the study isolates, while the multidrug resistance (MDR) rate was approximately 4.5% (18 of 397). Resistances to isoniazid (15.5%) and streptomycin (13.4%) were about twice as high as resistance to rifampin (RMP) (6.3%) and ethambutol (EMB) (6.0%). Importantly, 28% (7 of 25) of the RMP-resistant isolates were non-MDR isolates, as when a significant proportion of RMP-resistant isolates in a population are non-MDR, the predictive value of molecular detection of RMP resistance for MDR can be significantly reduced. Both identical and varied drug resistance patterns were seen in the same genotyping-defined clusters, suggesting that both primary and acquired resistance have contributed to the drug-resistant TB epidemic in Malatya, Turkey. In addition, drug-resistant cases were found to be more likely to be males (odds ratio [95% confidence interval], 1.82 [1.13, 2.94]), suggesting a potential role of gender in the epidemiology of drug-resistant TB in the study population. This study demonstrates that the integration of drug susceptibility testing with genotyping and epidemiological data analysis represents a useful approach to studying the epidemiology of drug-resistant TB.

A first insight into the genetic diversity and population structure of Mycobacterium tuberculosis in Zonguldak, Turkey

This study evaluated the molecular epidemiology and biodiversity of Mycobacterium tuberculosis isolates in Zonguldak, Turkey, and investigated the presence and significance of the LAM7-TUR clone by spoligotyping and mycobacterial interspersed repetitive unit-variable number tandem repeat (MIRU-VNTR) analysis. In total, 128 isolates were tested by spoligotyping; 25 selected isolates representative of the LAM7-TUR clone and similar types were also tested by MIRU-VNTR analysis. In total, 47 distinct patterns were revealed by spoligotyping, represented by 13 clusters containing between two and 28 isolates (94 isolates in total), and 34 unique patterns (a clustering rate of 73%). Using MIRU-VNTR analysis, the clustering relationships revealed by spoligotyping were confirmed. The most common spoligotyping profile was SIT53, followed by SIT41 (LAM7-TUR) and SIT50. The SIT284 clone was another phylogeographically specific clonal complex whose presence in Turkey may be endemic. The LAM7-TUR genotype was highly prevalent in Zonguldak.

Population-based molecular epidemiological study of tuberculosis in Malatya, Turkey

This investigation describes drug resistance patterns and genotyping data on a total of 145 Mycobacterium tuberculosis strains isolated between 2000 and 2004 in Malatya, Turkey. Drug susceptibility results indicated a total of 20% resistant and 4.8% of multidrug-resistant isolates. Spoligotyping resulted in 25 unique patterns and 120 strains in 19 clusters (2 to 33 strains per cluster). When the results were compared to an international spoligotyping database, 19 of 25 unique patterns matched existing shared spoligotype international types (SITs). This led to the description of 38 SITs with 139 strains and 6 orphan patterns (not previously reported). Five of the SITs (SIT759, SIT1936, SIT1937, SIT1938, and SIT2285) were newly created. The most prevalent spoligotype was SIT41 (LAM7-TUR) with 33 (23.9%) isolates. The repartition of strains according to major M. tuberculosis clades (in decreasing order) was as follows: ill-defined T clade (45.7%) > Latin American and Mediterranean (LAM; 29%) > Haarlem (15.9%). Strains belonging to Central Asian (CAS), East-African Indian (EAI), Beijing, and Africanum clades were absent in this setting. IS6110-restriction fragment length polymorphism (RFLP) resulted in 19 clusters (52 strains), with a final clustering rate of 35.9% and a recent transmission rate of 22.8%. Typing based on mycobacterial interspersed repetitive units (MIRUs) permitted us to identify 65 patterns (23 orphan patterns and 42 patterns that matched existing MIRU international types in an updated database). The combination of the three typing methods allowed us to calculate a final clustering rate of 22% and a significantly lower transmission rate of 13.1%. The discrimination achieved by IS6110-RFLP/MIRUs was not significantly improved by adding spoligotyping results (1.4%). We conclude that our patient population is infected by diverse M. tuberculosis populations; however, the majority of the ongoing transmission is due to "evolutionary recent" tuberculosis lineages belonging to principal genetic group 2 (PGG2; Haarlem and LAM) and PGG3 (ill-defined T clade), and most of it is attributable to the LAM7-TUR sublineage with an enhanced phylogeographical specificity for Turkey. An absence of lineages belonging to PGG1 clones (EAI, CAS, and Beijing, essentially found in Central, South, and Southeast Asia), is noteworthy.

Genetic diversity and major spoligotype families of drug-resistant Mycobacterium tuberculosis clinical isolates from different regions of Turkey

To highlight the transmission rate and major phylogenetic clades of drug-resistant Mycobacterium tuberculosis isolates, a total of 200 drug-resistant strains isolated in four different regions of Turkey (Marmara n=81; Mediterranean n=39; Aegean n=42; East Anatolia n=38), were typed by spoligotyping and IS6110-restriction fragment length polymorphism (RFLP). The major spoligotyping-defined shared-types (STs) and corresponding lineages were, ST 41 (22.5%, LAM7-TUR), ST53 (19.5%, ill-defined T super-family), ST 50 (6.5%, Haarlem 3), ST 1261 (4.5%, LAM7-TUR), ST 47 (3.5%, Haarlem 1), as well as two STs that belonged to undefined clades (ST 284, 3%, and ST 2067, 2.5%). The global distribution of major M. tuberculosis lineages among drug-resistant strains was as follows: T super-family (29%), Latin-American & Mediterranean (33.5%), Haarlem (14%), and the S lineage (3%). A high number of strains (n=29, 14.5%) showed patterns that did not fall within major clades described so far. A combination of spoligotyping and IS6110-RFLP fingerprinting methods resulted in a final clustering rate of 38.5% and a recent transmission rate of 25.5%. Our results underline the highly diverse nature of drug-resistant tuberculosis in our study population, as well as its ongoing transmission with lineages that are specific to these regions, the most predominant being the LAM7-TUR lineage which shows an enhanced phylogeographical specificity for Turkey.

Genetic diversity of Mycobacterium tuberculosis isolates at the Military Medical Academy in Ankara, Turkey

Genotyping of Mycobacterium tuberculosis isolates from infected individuals can play an important role in tracking the source of infection and unraveling the epidemiology of a tuberculosis pandemic. A total of 114 M. tuberculosis isolates were genotyped by spoligotyping and results were compared with an international spoligotype database (SpoIDB4). Twenty-one spoligotyping-defined clusters including 97 patients were established, and an additional 17 unique patterns were found. Ninety-eight (85.9%) isolates belonged to previously defined shared types (STs). The ST53 (ill-defined T1 superfamily, n=31), ST41 (LAM7-TUR family, n=9), ST118 (T undefined, n=8) and ST50 (Haarlem 3, n=6) were four major clusters of our isolates. After comparison with the international SpoIDB4 database, two new intrafile clusters, ST2136 and ST2139, were created and two new interfile clusters, ST2135 and ST2140, were defined. Eight (7%) of the 17 isolates with unique patterns were found to be orphans, whereas the STs of 9 isolates had previously been deposited in the international SpoIDB4 database. In addition, two isolates with an ST pattern characteristic of the Beijing family of M. tuberculosis were found. This study shows that, although ubiquitous spoligotypes are common, several spoligotypes specific to Turkey also exist. Thus, our study may help us to better understand the spread of M. tuberculosis genotypes to Turkey.

Cerebellar abscess and syringomyelia due to isoniazid-resistant Mycobacterium tuberculosis

A 19-year-old immunocompetent man was admitted to hospital with diplopia, nausea, vomiting and change in mental status. The patient had a history of tuberculous meningitis that was diagnosed at another hospital 6 months before the present admission, and at that time anti-tuberculosis treatment was initiated using a first-line drug combination. A computed tomography (CT) scan of the brain revealed non-communicating hydrocephalus. A ventriculo-peritoneal shunt was inserted surgically. Two months later, the patient was hospitalized again for fever, dysphagia and left hemiparesis. At that time, his cranial CT findings were within normal limits; however, magnetic resonance imaging (MRI) revealed an irregular multilocular peripheral contrast-enhancing lesion in the posterior fossa. The abscess was surgically drained. The presence of acid-fast bacilli in the abscess material was demonstrated by Ziehl-Neelsen staining. Mycobacterium tuberculosis grew on Lowenstein-Jensen culture medium, and the strain was found to be resistant to isoniazid. One month after the operation, the patient became quadriparetic. Cervical MRI revealed a cervico-thoracic syringomyelitic cavity, after which a syringoperitoneal shunt was placed. Treatment with four drugs was continued for 10 months, and then treatment with three drugs for a total period of 18 months. The patient recovered, with residual quadriparesis. Even though very rare, isoniazid-resistant M. tuberculosis may be the causative agent of progressive tuberculosis.

Simultaneous detection of isoniazid, rifampin, and ethambutol resistance of Mycobacterium tuberculosis by a single multiplex allele-specific polymerase chain reaction (PCR) assay

Prompt detection of drug resistance of Mycobacterium tuberculosis is essential for effective control of tuberculosis (TB). We developed a multiplex allele-specific polymerase chain reaction (MAS-PCR) that detects the most commonly observed isoniazid (INH), rifampin (RIF), and ethambutol resistance-associated mutations in a single assay. The usefulness of the newly developed method was evaluated with 174 clinical isolates of M. tuberculosis obtained from Turkey. Distinct PCR banding patterns were observed for different mutation profiles and the correlation between MAS-PCR results and DNA sequencing findings was 99.4%. With culture-based phenotypic drug susceptibility testing as a reference standard, the sensitivity and specificity of the newly developed MAS-PCR assay for drug resistance-related genetic mutation detection were determined to be 81.1% and 97.5% for INH, 93.0% and 98.9 % for RIF, and 54.5% and 68.0 % for ethambutol. MAS-PCR provides a rapid, potentially more cost-effective, method of detecting multidrug-resistant TB.

Genotyping of Mycobacterium tuberculosis clinical isolates in two cities of Turkey: description of a new family of genotypes that is phylogeographically specific for Asia Minor

Background

Population-based bacterial genetics using repeated DNA loci is an efficient approach to study the biodiversity and phylogeographical structure of human pathogens, such as Mycobacterium tuberculosis, the agent of tuberculosis. Indeed large genetic diversity databases are available for this pathogen and are regularly updated. No population-based polymorphism data were yet available for M. tuberculosis in Turkey, at the crossroads of Eurasia.

Results

A total of 245 DNAs from Mycobacterium tuberculosis clinical isolates from tuberculosis patients residing in Turkey (Malatya n = 147 or Ankara n = 98) were genotyped by spoligotyping, a high-throughput genotyping method based on the polymorphism of the Direct Repeat locus. Thirty-three spoligotyping-defined clusters including 206 patients and 39 unique patterns were found. The ST41 cluster, as designated according to the international SpolDB3 database project, represented one fourth and when gathered to three genotypes, ST53, ST50 and ST284, one half of all the isolates. Out of 34 clinical isolates harboring ST41 which were further genotyped by IS6110 and by MIRU-VNTR typing, a typical 2-copy IS6110-RFLP pattern and a "215125113322" MIRU-VNTR pattern were observed among 21 clinical isolates. Further search in various databases confirms the likely Turkish-phylogeographical specificity of this clonal complex.

Conclusion

We described a new phylogeographically-specific clone of M. tuberculosis, designated LAM7-TUR. Further investigations to assess its frequency within all regions of Turkey and its phylogeographical origin and phylogenetic position within the global M. tuberculosis phylogenetic tree will shed new light on its endemicity in Asia Minor.

Drug-resistant pulmonary tuberculosis in western Turkey: prevalence, clinical characteristics and treatment outcome

BACKGROUND

Although high antituberculosis (anti-TB) drug resistance rates have been reported in Turkey, the clinical characteristics and implications for the outcome of anti-TB treatment have not been fully investigated. We determined the prevalence of anti-TB drug resistance and examined demographic data, clinical characteristics and treatment outcome in relation to patterns of resistance.

METHODS

From the TB case registry of a university hospital and the two largest dispensaries in Manisa city, we identified all pulmonary TB cases with a culture-proven definitive diagnosis and antimicrobial susceptibility results for a 7-year period. We collected and analyzed demographic and clinical data and information on treatment outcome for those cases in relationship to anti-TB drug resistance.

RESULTS

Of 355 M. tuberculosis strains, 71.5% were susceptible to streptomycin, isoniazid, rifampicin and ethambutol. Any drug resistance and multi-drug resistance (MDR) rates were 21.1% and 7.3% and were higher in males (53% and 9%, respectively) than in females (22% and 1%, respectively). Drug resistance was significantly higher in old cases (acquired drug resistance) vs new cases (primary drug resistance), and was associated with treatmentfailure (P<0.001). The prevalence of MDR was significantly higher in the old cases (22.4%) than in the new cases (4.4%) (P<0.001). Symptoms, radiographic findings, associated diseases, and sputum smear positivity were unrelated to the development of resistance. The prevalence of any drug resistance and MDR was significantly higher in those with treatment failure than in patients with treatment success.

CONCLUSION

High resistance rates, particularly for acquired MDR, indicate a need for improvement in the TB control programme in our region.

Molecular characterization of isoniazid and rifampin resistance of Mycobacterium tuberculosis clinical isolates from Malatya, Turkey

Molecular characterization of drug resistance of Mycobacterium tuberculosis strains of different origins can generate information useful for developing molecular methods that are widely applicable for rapid drug resistance detection. Using DNA sequencing and allele-specific polymerase chain reaction (AS-PCR), we investigated genetic mutations associated with isoniazid (INH) and rifampin (RIF) resistance among 29 drug-resistant clinical isolates of M. tuberculosis collected from Malatya, Turkey, including 19 multi-drug-resistant (MDR) isolates. Point mutations were detected at codons 531, 516, 526, and 513 of the RNA polymerase beta- subunit gene (rpoB) in 10 (47.6%), five (23.8%), three (14.3%), and three (14.3%) of the 21 RIF-resistant isolates, respectively. Of the five isolates having mutations in codon 516, three also had mutations at codon 527; one had a concurrent mutation at codon 572. Mutations at codon 315 of the catalase-peroxidase-encoding gene (katG) were found in 17 (63.0%) of the 27 INH-resistant isolates. Interestingly, the katG codon 315 mutation was observed at a much higher frequency in MDR isolates than in INH-mono-resistant isolates ( approximately 79% vs. 25%). This study provided the first molecular characterization of INH and RIF resistance of M. tuberculosis clinical isolates from Eastern Turkey, and extended our knowledge of molecular basis of M. tuberculosis drug resistance.