Burden of non-tuberculous mycobacterial diseases in Saudi Arabian children: The first nationwide experience.

BACKGROUND: Non-tuberculous mycobacteria (NTM) causing pulmonary and extra-pulmonary diseases are increasing worldwide. A large paucity of data related to pediatric NTM diseases exists globally and particularly in Saudi Arabia. METHODS: The first nationwide exploratory study on existence of NTM diseases among Saudi Arabian children (0-14 years old) has been carried out during 2016-2017. Suspected NTM isolates with clinical and demographical data were enrolled from regional reference laboratories. Species level identification of isolates was carried out by commercial line probe assays and gene sequencing. RESULTS: In 12 months, 52 culture positive cases with 44(84.6%) confirmed disease incidences were identified. Demographically, Saudi nationals (86.5%) were dominated and 77.3% cases have different comorbid conditions. Lymphadenitis (40.4%) followed by 26.9% of pulmonary cases with 42.8% of confirmed clinical relevance were mainly reported. Species identification showed Mycobacterium simiae (31.8%), M. abscessus (23.1%) and nine other species including rarely encountering M. riyadhense. Ascites caused by M. monacense, pulmonary disease caused by M. riyadhense and M. monacense were rarest clinical events and reported for the first time globally in a pediatric cohort. CONCLUSIONS: Diverse NTM diseases even in immunocompetent children are an upcoming challenge in Saudi Arabia. Lack of awareness on NTM disease must be addressed with immediate development of management plans.

Demographic risk factors for extra-pulmonary tuberculosis among adolescents and adults in Saudi Arabia.

Despite low infectious potential of extrapulmonary tuberculosis (EPTB), it poses significant clinical challenges in terms of diagnosis and treatment monitoring. Understanding the main demographical risk factors for disease characteristics of EPTB plays a crucial role in speeding up diagnosis process and improving overall clinical experience. The aim of this study was to investigate the main demographical and clinical risk factors for EPTB among adults and adolescents for the first time in Saudi Arabia. A cross-sectional multicenter study was carried out on a collection of 902 extrapulmonary Mycobacterium tuberculosis complex (MTBC) isolates with demographical and clinical data. All isolates were subjected to spoligotyping and 24-loci based MIRU-VNTR typing. The association between two potential variables was assessed using odd ratios (OR) calculations. Independent risk factors for EPTB and diseases characteristics of EPTB were identified using multivariate regression model analyses. Gender was found to be significantly associated with lymph node, gastrointestinal, central nervous system and urogenital TB. Lymph node TB showed statistical association to age group below 25 years, non-Saudis and South East Asian ethnicity. While gastrointestinal TB demonstrated an association with patients above 60 years old, and Saudis. Multivariate analysis showed that gender is an independent risk factor to urogenital TB (p 0.03) and lymph node TB (p 0.005). On the other hands, South Asian (p 0.01) and South East Asian (p 0.03) ethnicities were both identified as independent risk factors significantly associated with EPTB. MTBC lineages, site of infections, gender, HIV and smear positivity showed no significant association. Nationwide qualitative-studies are highly warranted in the future to further understand the main demographic risk factors for disease characteristics of EPTB.

Impact of Mycobacterium tuberculosis complex lineages as a determinant of disease phenotypes from an immigrant rich moderate tuberculosis burden country.

BACKGROUND: Growing evidences suggested that the Mycobacterium tuberculosis complex (MTBC) lineages can determine the clinical outcome of pulmonary and extra-pulmonary tuberculosis. However, limited data only available revealing such association of bacterial genotypes and clinical phenotypes from immigrant rich countries. METHODS: A multicenter study has been carried out on a collection of 2092 (1003 extrapulmonary and 1089 pulmonary) MTBC isolates. Genotyping of all the isolates were carried out by spoligotyping and 24 loci based MIRU-VNTR typing. RESULTS: Demographically domination of young Saudi nationals (61.4%) and men (61.2%) were found in this cohort. Lymph nodes (62.4%) and gastrointestinal sites (16.7%) were the most common anatomical sites of infection. The predominant lineages were Delhi/CAS (26.9%), EAI (14.2%) and Ghana (9.9%). Mycobacterium africanum type I and II were reported for the first time in the country among extrapulmonary cases. 'Ancestral' lineages M.bovis (OR-5.22; 95% CI-2.23-8.22, p- < 0.001) and Delhi/CAS (OR-0.57; 95% CI-0.411-0.734, p- < 0.001) were directly associated with lymph node tuberculosis and gastrointestinal tuberculosis (M. bovis-OR-0.33; 95% CI-0.085-0.567, p-0.001 and Delhi/CAS-OR-1.87; 95% CI-1.22-2.53, p- < 0.001) respectively. Among the 'Modern' lineages, EAI showed significant association to central nervous system tuberculosis (OR-1.98; 95% CI-0.76-3.19, p-0.04) and Uganda-I to gastrointestinal tuberculosis (OR-2.41; 95% CI-0.77-4.06, p-0.02). CONCLUSIONS: The findings substantially contribute to the emerging evidences that MTBC lineages influence disease phenotypes and epidemiological consequences.

Drug-resistance profiling and transmission dynamics of multidrug-resistant Mycobacterium tuberculosis in Saudi Arabia revealed by whole genome sequencing.

BACKGROUND: In Saudi Arabia, cross-border transmission of multidrug-resistant (MDR) Mycobacterium tuberculosis complex (MTBC) strains might be particularly fostered by high immigration rates. Herein, we aimed to elucidate the transmission dynamics of MDR-MTBC strains and reveal a detailed prediction of all resistance-conferring mutations for the first- and second-line drugs. METHODS: We investigated all MDR-MTBC strains collected between 2015 and 2017 from provincial mycobacteria referral laboratories and compared demographic and clinical parameters to a cohort of non-MDR-TB patients using a whole genome sequencing approach. Clusters were defined based on a maximum strain-to-strain genetic distance of five single-nucleotide polymorphisms (SNPs) as surrogate marker for recent transmission, and then investigated molecular drug-resistance markers (37 genes). RESULTS: Forty-eight (67.6%) MDR-MTBC strains were grouped in 14 different clusters, ranging in size from two to six strains; 22.5% (16/71) of all MDR-MTBC isolates were predicted to be fully resistant to all five first-line drugs, and five strains (7.0%) exhibited fluoroquinolone resistance. Moreover, we revealed the presence of 12 compensatory mutations as well as 26 non-synonymous SNPs in the rpoC gene and non-hotspot region in rpoB, respectively. CONCLUSION: Optimized TB molecular surveillance, diagnosis, and patient management are urgently needed to contain MDR-MTBC transmission and prevent the development of additional drug resistance.

The first Saudi Arabian national inventory study revealed the upcoming challenges of highly diverse non-tuberculous mycobacterial diseases.

BACKGROUND: Incidences of nontuberculous mycobacteria (NTM) causing pulmonary and extrapulmonary diseases are reportedly increasing globally and the current epidemiologic situation in Saudi Arabia remains unclear. To study such trend, we carried out a nationwide systematic epidemiological study focusing on NTM diseases for the first time in the country. METHODS/PRINCIPLE FINDINGS: A nationwide collection of NTM isolates with clinical and demographical data was conducted for a period of 24 months. Primary species identification was carried out by line probe assays followed by sequencing of 16S rRNA, 16S-23S ITS region, rpoB and hsp65 genes. The laboratory findings were comprehensively analysed against demographical and clinical data. A total of 527 isolates were enrolled with a higher proportion of Saudi citizens (76.5%), elderly (>60 years) patients (34.2%), and male gender (65.3%) respectively. Overall, 75.1% isolates were pulmonary origin with a proven clinical significance of 44.7%. In total, 34 NTM species including 17 rare species were identified, in addition to 8 'undefined' isolates. M.simiae (22.6%), M.fortuitum (18.1%) and M.abscessus (17.8%) were predominant species. Interestingly, 27 new cases of clinically relevant M.riyadhense were also noticed (Primary data on emergence of rare NTM species and M.riyadhense has been recently reported). Results showed, rare clinical events such as mycobacteremia, cecum abscess, peritonitis and ascites caused by M.wolinskyi, M.holsaticum, M.duvalii and M.monacence respectively. Diabetes mellitus (P value-0.04) and previous history of tuberculosis (P value- 0.001) were identified as independent risk factors associated with NTM diseases. CONCLUSIONS/SIGNIFICANCE: NTM disease spectrum and pathogen diversity is an emerging challenge to any nation, including Saudi Arabia. Therefore, more priorities will be given to NTM's with an immediate initiative to develop diagnostic infrastructures and disease management plans.

Mycobacterium riyadhense in Saudi Arabia.

We explored in detail the nationwide existence of Mycobacterium riyadhense in Saudi Arabia. In 18 months, 12 new cases of M. riyadhense infection were observed, predominantly among Saudi nationals, as a cause of pulmonary disease. M. riyadhense may be emerging as a more common pathogen in Saudi Arabia.

First Insight Into the Fluoroquinolone and Aminoglycoside Resistance of Multidrug-Resistant Mycobacterium tuberculosis in Saudi Arabia.

AbstractIn Saudi Arabia, there were no nationwide screening studies conducted so far to determine the aminoglycoside and fluoroquinolone resistance among multidrug-resistant tuberculosis (MDR-TB) isolates. Therefore, as the first attempt in the country, a retrospective analysis has been conducted on a nationwide collection of 2,956 M. tuberculosis clinical isolates screened with phenotypic drug susceptibility testing to define MDR-TB. Enrolled MDR-TB isolates were subjected to second-line drug susceptibility testing, detection of mutations conferring resistance to aminoglycosides and fluoroquinolone, followed by 24-loci mycobacterial interspersed repetitive unit-variable number of tandem repeat typing and spoligotyping. Overall, 83 isolates were identified as MDR-TB, and 13 (15.7%) isolates showed resistance to second-line drugs. Moxifloxacin (low level) showed higher resistant rates (10.8%) followed by ofloxacin (7.2%), capreomycin (3.6%), kanamycin (3.6%), and amikacin (2.4%). Overall fluoroquinolone resistance was 12%, whereas aminoglycoside resistance was 7.2%. Predominant mutations conferring resistance to fluoroquinolone were found in gyrA A90V and D94G, whereas aminoglycoside resistance was observed only with rrs gene A1401G mutation. The corresponding strain lineages predominated with Indo-Oceanic and East-African Indian origin. Interestingly, none of the isolates with second-line drug resistance was defined as extensively drug-resistant TB (XDR-TB). Surprisingly, many isolates (50.6%) were panresistant to first-line drugs. Saudi Arabia faces considerable burden of fluoroquinolone- and aminoglycoside-resistant MDR-TB. Higher incidence of panresistant MDR-TB reveals a threat for the emergence of XDR-TB strains in the near future.

Diagnostic potential of interferon-gamma release assay to detect latent tuberculosis infection in kidney transplant recipients.

BACKGROUND: Latent tuberculosis (TB) infection (LTBI) is screened by using clinical assessment, tuberculin skin test (TST), chest radiography, and recently by interferon-gamma release assays (IGRA). The objective of this study was to evaluate the diagnostic potential of QuantiFERON® -TB Gold In-Tube test (QFT) for diagnosing LTBI in patients planned for kidney transplantation. METHODS: All adult patients with end-stage renal disease, evaluated for kidney transplantation in a referral center from August 2008 till May 2013, were enrolled, after consenting in a prospective, observational, non-interventional study. LTBI diagnosis was conducted by TST, chest x-ray, and clinical assessment, followed by IGRA by QFT. RESULTS: Overall, 278 patients were enrolled and kidney transplantation was performed in 173 patients. Contributed follow-up was 836.5 patient-years, and TB-free transplant duration was 478.5 patient-years. By standard methods, LTBI was diagnosed in 14 patients. Peri-transplant chemoprophylaxis was given to 53 patients, which included recipients of organs from all deceased donors and living donors with LTBI. QFT was positive in 70 patients, negative in 200 patients, and indeterminate in 8 patients. The agreement between LTBI diagnosis using standard methods and IGRA by QFT was poor (kappa: 0.089+0.046, P-value=.017). Twenty-seven of the QFT-positive patients were transplanted and only one was given isoniazid preventive therapy. None of the transplant recipients developed TB after a median follow-up of 25 months (range 2-58 months, mean 27 months). CONCLUSIONS: The agreement of the QFT with standard diagnosis of LTBI in kidney transplant recipients was poor.

Emergence of Rare Species of Nontuberculous Mycobacteria as Potential Pathogens in Saudi Arabian Clinical Setting.

BACKGROUND: Clinical relevance of nontuberculous mycobacteria (NTM) is increasing worldwide including in Saudi Arabia. A high species diversity of NTM's has been noticed in a recent study. However, the identification in diagnostic laboratories is mostly limited to common species. The impact of NTM species diversity on clinical outcome is so far neglected in most of the clinical settings. METHODOLOGY/PRINCIPAL FINDINGS: During April 2014 to September 2015, a nationwide collection of suspected NTM clinical isolates with clinical and demographical data were carried out. Primary identification was performed by commercial line probe assays. Isolates identified up to Mycobacterium species level by line probe assays only were included and subjected to sequencing of 16S rRNA, rpoB, hsp65 and 16S-23S ITS region genes. The sequence data were subjected to BLAST analysis in GenBank and Ez-Taxon databases. Male Saudi nationals were dominated in the study population and falling majorly into the 46-59 years age group. Pulmonary cases were 59.3% with a surprising clinical relevance of 75% based on American Thoracic Society guidelines. Among the 40.7% extra-pulmonary cases, 50% of them were skin infections. The identification revealed 16 species and all of them are reporting for the first time in Saudi Arabia. The major species obtained were Mycobacterium monascence (18.5%), M. cosmeticum (11.1%), M. kubicae (11.1%), M. duvalli (7.4%), M.terrae (7.4%) and M. triplex (7.4%). This is the first report on clinical relevance of M. kubicae, M. tusciae, M.yongonense, M. arupense and M.iranicum causing pulmonary disease and M. monascence, M. duvalli, M. perigrinum, M. insubricum, M. holsaticum and M. kyorinense causing various extra-pulmonary diseases in Saudi Arabia. Ascites caused by M. monascence and cecum infection by M. holsaticum were the rarest incidents. CONCLUSIONS/SIGNIFICANCE: To the first time in the country, clinical significance of various rare NTM's are well explored and the finding warrants a new threat to the Saudi Arabian clinical settings.

Interferon Gamma Release Assay versus Tuberculin Skin Testing among Healthcare Workers of Highly Diverse Origin in a Moderate Tuberculosis Burden Country.

Health care workers (HCW's) are always at an increased risk of contracting tuberculosis (TB) infection. In Saudi Arabia, Interferon Gamma Release Assay (IGRA) has not been evaluated as a screening tool for latent TB infection (LTBI) among HCW's considering their high demographic diversity. During February 2012 to January 2015 a cross sectional study has been conducted in a tertiary care center with maximum demographically diverse staff population in the capital city-Riyadh. After a short interview and consenting, all the candidates were subjected to tuberculin skin test (TST) and QuantiFERON TB gold In-tube test (QFT). A logistic regression analysis was carried out for establishing the associations between putative risk factors and the diagnostic tests. The candidates were classified according to geographical origin and a detailed analysis was conducted on the impact of their origin towards the results of TST and QFT. Of the 1595 candidates enrolled, 90.6% were BCG vaccinated, female (67.9%) and mainly nurses (53.2%). Candidates with high risk of suspected or confirmed TB patient exposure were 56.1% and 76.5% of them had <10 year's work experience. TST positivity was observed in 503 (31.5%) candidates, while QFT was positive among 399 (25%). Majority of the candidates were non-Saudi (83%) and predominantly (52.4%) from Western Pacific region. Concordant results were obtained in 14.2% of positive cases and 57.7% negative cases. The disagreements between the two tests were relatively high (kappa co-efficient-0.312±0.026, p value- <0.00001) as TST positive/QFT negative discordance was 54.8% while TST negative/QFT positive discordance was 15.7%. Age of the candidates, BCG vaccination, and South East Asian origin were associated with TST positivity while Occupational TB exposure and geographical origin of the candidates were associated with QFT positivity. A regular follow up on recently TST converted candidates showed no progression to active TB. The putative factors associated with the discordance were origin of the candidate (p value <0.001), profession (p value-0.001), BCG vaccination (p value-0.001) and occupational TB exposure level (P value-0.001). The study demonstrated high level prevalence of LTBI among the demographically diverse study candidates. The agreement between QFT and TST was poor, thus QFT alone cannot be recommended in our setting for a routine LTBI screening. Origin of the candidates has strong association with the results of TST and QFT. The discordant results particularly TST negative and QFT positive needs more detailed analysis.

Tuberculosis in Saudi Arabia: the journey across time.

Saudi Arabia is the third-largest Arab country with a moderate annual burden of tuberculosis. However, tuberculosis (TB) is among several infectious diseases that have not been brought under control, despite the government's considerable efforts. This is clearly evidenced by the ongoing transmission of several imported and indigenous clades of Mycobacterium tuberculosis. In addition, the country faces the threat from rising proportions of extrapulmonary TB, non-tuberculous mycobacterial infections, and drug resistance. Furthermore, the country falls behind the global targets set by World Health Organization for the success rate of TB treatment. The country needs more population-based research studies, centralized and easily accessible clinical data registries, and centralized research and diagnostic facilities. This review focused on the trends of mycobacterial infections and on future proposals to improve TB control measures in Saudi Arabia.

Exploring the sociodemographic and clinical features of extrapulmonary tuberculosis in Saudi Arabia.

BACKGROUND: Saudi Arabia annually reports a relatively higher proportion (28-32%) of extrapulmonary tuberculosis (EPTB) cases in comparison to other global regions. However, there were few studies conducted so far to determine the sociodemographic factors and clinical manifestations associated with EPTB at a nationwide level. METHODOLOGY: A retrospective analysis on culture positive EPTB isolates collected from all the provinces of the country were conducted for a period of 12 months to determine the spectrum of diversity in EPTB infection sites and the confounding factors. A detailed clinical and demographical data analysis was carried out along with first line drug susceptibility testing. PRINCIPAL FINDINGS: Intra-thoracic and extra-thoracic lymph nodes (44.6%) were the most common sites of infection followed by gastrointestinal (17.3%) and central nervous systems (11.8%). Male patients were mostly infected (58.8%), in contrary to the global trend. Any drug resistance was observed in 23.1% isolates with a 2.1% of multi-drug resistance. HIV reactivity was found only in 2.2% cases. A higher proportion of Saudi nationals (58.8%) were infected compared to the immigrants, descending mostly from South Asia (34.4%) and South East Asia (31.2%). The Saudi population predominated with all forms of EPTB while immigrants showed no significant variations. CONCLUSIONS: Saudi Arabia faces a serious threat from EPTB, particularly to the central nervous system and gastrointestinal systems. More effective diagnostic strategies and control measures must be implemented to reduce the high rate of EPTB in the country. In addition, these findings warrant further detailed research to explore all related comorbid conditions of EPTB development, particularly the host-related factors.

Mapping the epidemiology and trends of extra-pulmonary tuberculosis in Saudi Arabia.

An extra-pulmonary tuberculosis (EPTB) infection rate of 30% in Saudi Arabia remains above the global rate. A variable rate of infection in each province has been reported and the involvement of most organs has been cited. Nationwide collective data on the current trends of infection are scarce and the factors behind the increased rate of EPTB are perplexing. This review endeavors to shed light into the epidemiology of EPTB, various types of infections sites, geographical differences in the infection rate, known risk factors, and challenges in the diagnosis and management of EPTB in Saudi Arabia.

Molecular confirmation of Bacillus Calmette Guerin vaccine related adverse events among Saudi Arabian children.

BACKGROUND: Bacillus Calmette Guerin (BCG) is the only available vaccine for tuberculosis (TB). Low grade complications in healthy recipients and disseminated vaccine associated complications among immuno-suppressed individuals were noticed globally after administration. Recently a series of clinically suspected BCG associated suppurative and non-suppurative lymphadenitis cases were reported from different regions of Saudi Arabia. However a molecular confirmative analysis was lacking to prove these claims. METHODOLOGY: During 2009-2010, 42 Mycobacterium bovis BCG suspected clinical isolates from children diagnosed with suppurative lymphadenitis from different provinces of the country were collected and subjected to 24 loci based MIRU-VNTR typing, spoligotyping and first line anti-TB drugs susceptibility testing. PRINCIPAL FINDINGS: Of the total 42 cases, 41 (97.6%) were Saudi nationals and particularly male (64.3%). Majority of the cases were aged below 6 months (83.3%) with a median of age 4 months. All the enrolled subjects showed left axillary mass which suppurated in a median of 4 months after vaccination. Among the study subjects, 1 (2.4%) case was reactive to HIV antigen and 2 (4.8%) case had severe combined immunodeficiency. Genotyping results showed that, 41 (97.6%) isolates were identical to the vaccine strain Danish 1331 and one to Tokyo 172-1. Phylogenetic analysis revealed all the Danish 1331 isolates in a single cluster. CONCLUSION: Elevated proportion of suppurative lymphadenitis caused by M. bovis BCG reported in the country recently is majorly related to the vaccine strain Danish 1331. However lack of nationwide data on real magnitude of BCG related adverse events warrants population centric, long term future studies.

Occurrence of diverse mutations in isoniazid- and rifampicin-resistant Mycobacterium tuberculosis isolates from autochthonous and immigrant populations of Saudi Arabia.

For the first time in Saudi Arabia, the impact of a patient's ethnic background on mutations conferring resistance to rifampicin (RIF) and isoniazid (INH) in Mycobacterium tuberculosis isolates was analyzed on a nationwide sample collection. Four hundred fifteen isolates were subjected to drug susceptibility testing, mutation analysis, spoligotyping, and 24 loci-based Mycobacterial Interspersed Repetitive Units-Variable Number Tandem Repeat typing, respectively. Phenotypically, 41 (9.9%) isolates were resistant to RIF, 239 (57.6%) to INH, and 135 (32.5%) to both RIF and INH, respectively. Forty (9.6%), 236 (56.8%), and 133 (32%) isolates were determined as resistant to RIF, INH, and to both by molecular assay. Codon 531 (S531L) mutations (69.4%) in the rpoB gene and codon 315 (S315T) mutations (67.2%) in the katG gene were the most prominent among RIF- and INH-resistant isolates, respectively. The autochthonous population showed a predominance of rpoB codon 516 and 526 mutations, while the inhA promoter position -15 and -8 mutations were prominent among immigrants. A strain cluster ratio of 32% (30 clusters) was observed and 24 clusters displayed identical mutations. Overall, Euro-American lineages were predominant. However, Beijing (56.7%) and EAI (42.7%) were noticed with the highest cluster rate. In Saudi Arabia, the occurrence of mutations responsible for INH and RIF resistance was significantly associated with the ethnic origin of the patient.

Tuberculosis transmission among immigrants and autochthonous populations of the eastern province of Saudi Arabia.

BACKGROUND: Eastern province of Saudi Arabia is an industrial zone with large immigrant population and high level of tuberculosis case notification among immigrants. The impact of immigration and current trends of tuberculosis transmission among immigrants and autochthonous population in the region had not been investigated so far using molecular tools. METHODOLOGY: During 2009- 2011, a total of 524 Mycobacterium tuberculosis isolates were collected from the central tuberculosis reference laboratory, representing an estimated 79.2% of the culture-positive tuberculosis cases over the study period in the province. These isolates were genotyped by using 24 locus-based MIRU-VNTR typing and spoligotyping followed by first line drug susceptibility testing. The molecular clustering profiles and phylogenetic diversity of isolates were determined and compared to the geographical origins of the patients. PRINCIPLE FINDINGS: Genotyping showed an overall predominance of Delhi/CAS (29.4%), EAI (23.8%) and Ghana (13.3%) lineages, with slightly higher proportions of Delhi/CAS among autochthonous population (33.3 %) and EAI (30.9%) among immigrants. Rate of any drug resistance was 20.2% with 2.5% of multi-drug resistance. Strain cluster analysis indicated 42 clusters comprising 210 isolates, resulting in a calculated recent transmission index of 32.1%. Overall shared cluster ratio was 78.6% while 75.8% were shared between autochthonous population and immigrant population with a predominance of immigrants from South east Asia (40.7%). In contrast, cross national transmission within the immigrant population was limited (24.2%). Younger age (15-30- p value-0.043, 16-45, p value 0.030), Saudi nationality (p value-0.004) and South East Asian origin (p value-0.011) were identified as significant predisposing factors for molecular strain clustering. CONCLUSIONS: The high proportion of molecular clusters shared among the autochthonous and immigrant populations suggests a high permeability of tuberculosis transmission between both populations in the province. These results prompt for the need to strengthen the current tuberculosis control strategies and surveillance programs.

Emergence of clinically relevant Non-Tuberculous Mycobacterial infections in Saudi Arabia.

BACKGROUND: Non-Tuberculous Mycobacteria (NTM) are emerging around the world due to a higher prevalence of immunosuppressive illness and therapy. Saudi Arabia is not an exception as there have been novel mycobacterial species also identified. In addition, several published case reports from different parts of the country suggest a growing pathogenic potential of NTM. As the first nationwide study, we sought to gain an insight into the species diversity of NTM clinical isolates. METHODOLOGY/PRINCIPAL FINDINGS: During June 2009-July 2010, 95 clinical isolates were collected from tuberculosis reference laboratories in major provinces within Saudi Arabia and subjected to standard line probe assay techniques to identify their species. Diagnostic guidelines of the American Thoracic Society were applied to determine the clinical relevance of respiratory isolates. Species diversity (13 species) was very high and dominated (61.0%) by rapid growing NTM. The major species obtained were Mycobacterium abscessus, M. fortuitum, M. intracellulare followed by M. kansassi, M. gordanae and M. avium. Interestingly this study reports for the first time the clinical relevance of M. celatum, M. xenopi, M. scrofulceum, M. lentiflavum, M. asiaticum and M. simiae in Saudi Arabia. Of the total, 67.1% were clinically relevant respiratory cases, 23.2% were non-respiratory cases and 9.7% were respiratory colonizers. Coexisting illness was reported in 53.7% of the studied cases. The major risk factors observed among the patients were previous history of tuberculosis, chronic obstructive pulmonary disorder and human immunodeficiency virus infection. CONCLUSION/SIGNIFICANCE: The high rates of clinically confirmed respiratory cases suggest that NTM infections are indeed a new challenge to health authorities. The current findings show an opposite picture of the Western world where M. avium complex and particularly slow growing NTM are the most predominant respiratory pathogens. The complexity of species demands an immediate strengthening of the current diagnostic facilities.

Epidemiology of antituberculosis drug resistance in Saudi Arabia: findings of the first national survey.

The real magnitude of antituberculosis (anti-TB) drug resistance in Saudi Arabia is still unknown because the available data are based on retrospective laboratory studies that were limited to hospitals or cities. A representative national survey was therefore conducted to investigate the levels and patterns of anti-TB drug resistance and explore risk factors. Between August 2009 and July 2010, all culture-positive TB patients diagnosed in any of the tuberculosis reference laboratories of the country were enrolled. Isolates obtained from each patient were tested for susceptibility to first-line anti-TB drugs by the automated Bactec MGIT 960 method. Of the 2,235 patients enrolled, 75 cases (3.4%) were lost due to culture contamination and 256 (11.5%) yielded nontuberculous mycobacteria (NTM). Finally, 1,904 patients (85.2% of those enrolled) had available drug susceptibility testing results. Monoresistance to streptomycin (8.1%; 95% confidence interval [CI], 7.2 to 9.1), isoniazid (5.4%; 95% CI, 4.7 to 6.2), rifampin (1%; 95% CI, 0.7 to 1.3) and ethambutol (0.8%; 95% CI, 0.5 to 1.2) were observed. Multidrug-resistant TB (MDR-TB) was found in 1.8% (95% CI, 1.4 to 2.4) and 15.9% (95% CI, 15.4 to 16.5) of new and previously treated TB cases, respectively. A treatment history of active TB, being foreign-born, having pulmonary TB, and living in the Western part of the country were the strongest independent predictors of MDR-TB. Results from the first representative national anti-TB drug resistance survey in Saudi Arabia suggest that the proportion of MDR-TB is relatively low, though there is a higher primary drug resistance. A strengthened continuous surveillance system to monitor trends over time and second-line anti-TB drug resistance as well as implementation of innovative control measures, particularly among immigrants, is warranted.

Current trends of Mycobacterium tuberculosis molecular epidemiology in Saudi Arabia and associated demographical factors.

Data are scarce on demographical factors related to the population structure of Mycobacterium tuberculosis in Saudi Arabia. A study was conducted on 902 clinical isolates to explore current trends in the phylogeography and associated demographical factors of tuberculosis by using spoligotyping and 24 loci based MIRU-VNTR typing. Young male patients (aged 16-29 and 30-44) were predominant in this cohort. The phylogenetic diversity among M. tuberculosis isolates was found high, as almost all known genetic lineages were identified. Delhi/CAS (26.4%), EAI (13.7%) and Haarlem (11.3%) were the most common lineages observed, particularly among the low age groups (16-29 and 30-44 years), whereas elderly patients (>60 years) showed a predominance in the lineages S, Ghana, TUR and Uganda-I. A statistically significant association was observed between gender of the patients and lineages of EAI (p value 0.026) and LAM (p value 0.005). Overall, molecular strain cluster rate was 34.4% with an elevated rate among patients aged below 15 years (43.1%), while cases among the elderly (>60 years) showed the lowest degree of clustering (12.5%). The largest level of clustering was noticed among cases caused by strains of the lineages Haarlem (59.8%), Beijing (55.8%) and LAM (42.8%). The current population structure of M. tuberculosis in Saudi Arabia is highly diverse with significant associations to demography, transmission dynamics and origin of the patients. The difference in genotype distributions among low and high aged patients reflects the ongoing change in the strain population structure in the country.