Tuberculosis in Australia: bacteriologically-confirmed cases and drug resistance, 2011. A report of the Australian Mycobacterium Reference Laboratory Network.

The Australian Mycobacterium Reference Laboratory Network collects and analyses laboratory data on new cases of disease caused by the Mycobacterium tuberculosis complex. In 2011, a total of 1,057 cases were identified bacteriologically; an annual reporting rate of 4.6 cases per 100,000 population. Eighteen children aged less than 15 years plus an additional 11 children from the Torres Strait Protected Zone had bacteriologically-confirmed tuberculosis. Results of in vitro drug susceptibility testing were available for 1,056 isolates for isoniazid, rifampicin, ethambutol, and pyrazinamide. A total of 107 (10.0%) isolates of M. tuberculosis were resistant to at least one of these anti-tuberculosis agents. Resistance to at least isoniazid and rifampicin (defined as multi-drug resistance, MDR) was detected in 25 (2.4%) isolates; 18 were from the respiratory tract (sputum n=14, bronchoscopy n=3, tissue n=1). Ten (55.6%) of the MDR-TB-positive sputum specimens were smear-positive, as was a single sample from a lymph node. Ten patients with MDR-TB were Papua New Guinea (PNG) nationals in the Torres Strait Protected Zone. If these PNG nationals are excluded from the analysis, the underlying MDR-TB rate in Australia was 1.4%. No cases of extensively drug-resistant TB (defined as MDR-TB with additional resistance to a fluoroquinolone and an injectable agent) were detected in 2011.

Genetic diversity of Mycobacterium tuberculosis isolates obtained from patients with pulmonary tuberculosis in Beira city, Mozambique.

BACKGROUND: Tuberculosis (TB) represents a serious public health problem in Mozambique, with an estimated incidence rate of 548 cases per 100,000 population in 2011. Information on the molecular epidemiology of Mycobacterium tuberculosis (MTB) strains circulating in Mozambique is limited. This study provides the first description of the genetic diversity of MTB strains circulating in Beira city, the second largest town in Mozambique. METHODS: A total of 67 MTB isolates were tested to determine genetic lineages and diversity. The genetic lineages were determined using real-time PCR while genetic diversity was assessed by obtaining Mycobacterial Interspersed Repetitive Unit-Variable Numbers of Tandem Repeat profiles. RESULTS: Only three of the six major lineages were represented, with 41 (61%) strains belonging to lineage 1, 25 (37%) belonging to lineage 4 and the remaining isolate belonging to lineage 3. No lineage 2 strains (containing the Beijing family) were identified. A high degree of diversity amongst the strains from both lineages 1 and 4 were observed. Comparison of the profiles of representative strains with those of reference strains in the MIRU-VNTRplus database revealed that all lineage 1 isolates clustered with the Eastern African Indian (EAI) 5 sub-family. The lineage 4 strains clustered with a variety of different sub-family strains, including the Latin-American-Mediterranean (LAM) 1 sub-family, the Haarlem, Uganda 1 and Cameroon sub-families and the T2-S sub-family. CONCLUSIONS: The TB epidemic in Beira city is caused by a diverse group of MTB strains predominantly belonging to lineages 1 and 4.

Tuberculosis in Australia: bacteriologically confirmed cases and drug resistance, 2010. A report of the Australian Mycobacterium Reference Laboratory Network.

The Australian Mycobacterium Reference Laboratory Network collects and analyses laboratory data on new cases of disease caused by the Mycobacterium tuberculosis complex. In 2010, a total of 1,051 cases were identified by bacteriology; an annual reporting rate of 4.7 cases per 100,000 population. Twelve children aged less than 10 years had bacteriologically-confirmed tuberculosis. Results of in vitro drug susceptibility testing were available for 1,050 isolates for isoniazid (INH), rifampicin (RIF), ethambutol (EMB), and pyrazinamide (PYZ). A total of 126 (12%) isolates of M. tuberculosis were resistant to at least one of these anti-tuberculosis agents. Resistance to at least INH and RIF (defined as multi-drug resistance, MDR) was detected in 37 (3.5%) isolates, including three Australians with extensive travel in high burden TB countries; 33 were from the respiratory tract (sputum n=28, bronchoscopy n=5). Nineteen (65.5%) of the MDR-TB-positive sputum specimens were smear-positive, as were single samples from bronchoscopy and urine. Sixteen patients with MDR-TB were from the Torres Strait Protected Zone. If these Papa New Guinea nationals are excluded from the analysis, the underlying MDR-TB rate in Australian isolates was 2.0%. One case of extensively drug-resistant TB (defined as MDR-TB with additional resistance to a fluoroquinolone and an injectable agent) was detected in 2010.

Tuberculosis in Australia: bacteriologically confirmed cases and drug resistance, 2008 and 2009. A report of the Australian Mycobacterium Reference Laboratory Network.

There were 886 and 1,062 bacteriologically-confirmed cases of tuberculosis (TB) in 2008 and 2009, representing an annual rate of 4.1 and 4.9 cases per 100,000 population respectively. Over the 2 years, a total of 23 children aged under 10 years (male n = 13, female n = 10) had bacteriologically confirmed tuberculosis, including 3 children with TB meningitis. Results of in vitro drug susceptibility testing were available for 885 of 886 and 1,060 of 1,062 isolates for isoniazid (INH), rifampicin (RIF), ethambutol (EMB), and pyrazinamide (PYZ) in 2008 and 2009 respectively. In 2008, a total of 94 (10.7%) isolates of Mycobacterium tuberculosis complex were resistant to at least one of the anti-tuberculosis agents. Any resistance to INH was noted for 76 (8.7%), 23 (2.6%) for RIF, 10 (1.1%) for EMB and 9 (1.0%) for PYZ. Resistance to at least INH and RIF (defined as multidrug-resistant TB (MDR-TB) was detected in 21 (2.4%) isolates. None of the 21 MDR-TB isolates had resistance to either ofloxacin or the injectable agents. In 2009, a total of 168 (15.9%) were resistant to at least one of the anti-TB agents. Any resistance to INH was noted for 150 (14.2%) isolates, 37 (3.5%) for RIF, 5 (0.5%) for EMB and 13 (1.2%) for PYZ. A total of 31 (2.9%) isolates were MDR-TB. In 2009, there were 2 cases of quinolone resistance in MDR-TB from persons born overseas. Mono-resistance to INH was the most commonly detected resistance with 33 and 80 isolates in 2008 and 2009, respectively. Mono-resistance to RIF was infrequently encountered with 2 and 5 isolates in 2008 and 2009 respectively. There were six and 11 MDR-TB patients from the Papua New Guinea (PNG) - Torres Strait Islands (TSI) cross-border region in 2008 and 2009 respectively. The PNG-TSI zone now contributes a substantial proportion of MDR-TB cases to the database. In addition, there were 24 isolates of Mycobacterium bovis bacille Calmette Guérin (BCG), 15 were cultured from males (4 aged < or = 5 years) and from 9 females (5 aged < or = 5 years). The predominant site of isolation was from vaccination abscess. Eight males (range: 57-87 years) had M. bovis BCG isolated from urine or blood culture.

Tuberculosis in Australia: bacteriologically confirmed cases and drug resistance, 2007. A report of the Australian Mycobacterium Reference Laboratory Network.

The Australian Mycobacterium Reference Laboratory Network collects and analyses laboratory data on new cases of disease caused by the Mycobacterium tuberculosis complex. In 2007, a total of 872 cases were identified by bacteriology; an annual reporting rate of 4.1 cases per 100,000 population. Isolates were identified as M. tuberculosis (n=867), M. africanum (n=4) and M. bovis (n=1). Fifteen children aged under 10 years had bacteriologically-confirmed tuberculosis. Results of in vitro drug susceptibility testing were available for 871 of 872 isolates for isoniazid (H), rifampicin (R), ethambutol (E), and pyrazinamide (Z). A total of 98 (11.3%) isolates of M. tuberculosis were resistant to at least one of these anti-tuberculosis agents. Resistance to at least H and R (defined as multi-drug resistance, MDR) was detected in 24 (2.8%) isolates, all from overseas-born patients; 17 were from the respiratory tract (sputum n=16, endotracheal aspirate n=1). Thirteen patients with MDR-TB were from the Papua New Guinea-Torres Strait Islands zone. Of the 98 M. tuberculosis isolates resistant to at least one of the standard drugs, 54 (55.1%) were from new cases, 9 (9.2%) from previously treated cases, and no information was available on the remaining 35 cases. Seven were Australian-born, 90 were overseas- born, and the country of birth of 1 was unknown. Of the 90 overseas-born persons with drug resistant disease, 66 (73.3%) were from 5 countries: India (n=16); Papua New Guinea (n=15); the Philippines (n=12); Vietnam (n=12); and China (n=11). No XDR-TB was detected in 2007.

Susceptibility of Mycobacterium bovis BCG vaccine strains to antituberculous antibiotics.

Mycobacterium bovis BCG is one of the most commonly administered vaccines. Complications, including disseminated BCG disease, are rare but increasingly reported in immunodeficient children. There is growing recognition of the importance of differences between BCG vaccine strains. We determined the susceptibilities of five genetically distinct BCG vaccine strains to 12 antituberculous drugs.

Epidemiology of laboratory confirmed tuberculosis in Victoria, 1990 to 2004.

In Australia, most cases of tuberculosis (TB) occur in migrants. To inform control strategies for this group, we investigated all laboratory confirmed tuberculosis cases diagnosed by the State TB reference laboratory in Victoria between 1990 and 2004. The laboratory data were matched to notification data to determine country of birth and a multivariate model was constructed to compare Australian and non-Australian-born patients. The proportion of non-Australian-born cases increased over the period of the study and a shift in cases from South East Asia to African countries was observed. Non-Australian-born cases were more likely to be young, female, have extrapulmonary disease and show first line TB drug resistance. The shift in country of birth of TB cases in Victoria reflects migration patterns and the corresponding epidemiology of TB in the country of origin of these migrants. Ongoing migration from countries with high TB incidence raises the question whether it is possible to eliminate TB from Australia and new control strategies should be considered.

Tuberculosis in Australia: bacteriologically confirmed cases and drug resistance, 2006 a report of the Australian Mycobacterium Reference Laboratory Network.

In 2006, the Australian Mycobacterium Reference Laboratory Network identified 905 bacteriologically confirmed cases of disease caused by members of the Mycobacterium tuberculosis complex. The annual reporting rate was 4.4 cases per 100,000 population. Of the 905 isolates, 903 were Mycobacterium tuberculosis and two were Mycobacterium bovis. Fourteen children aged under 10 years (male n = 5, female n = 9) had bacteriologically confirmed tuberculosis. A total of 100 (11.1%) isolates of M. tuberculosis were resistant to at least one first-line anti-tuberculosis agent. Resistance to at least H and R (defined as multi-drug resistant--MDR) was detected in 22 (2.4%) M. tuberculosis isolates. Of the 22 MDR-TB isolates, 17 were from the respiratory tract (sputum n = 11 bronchoscopy n = 5, nasogastric aspirate n = 1), three from lymph node, one from a sacral mass, and one sterile site fluid. Smear-positive specimens from the MDR-TB cases were found in sputum (n = 6), lymph node (n = 2), and one each of bronchoscopy and nasogastric aspirate specimens. The country of birth was known for all 100 cases with a drug-resistant isolate; 10 of whom were born in Australia. The 90 overseas-born cases with drug-resistant disease were from 27 countries. Two Australian-born cases had MDR-TB; one had worked extensively in the Philippines; the other was a contact of a known MDR-TB case. No cases of extensively drug-resistant TB (XDR-TB) were identified in 2006. However, an on-going review of laboratory data identified one case of XDR-TB in 2004.

Tuberculosis in Australia: bacteriologically confirmed cases and drug resistance, 2005.

The Australian Mycobacterium Reference Laboratory Network (AMRLN) collects and analyses laboratory data on new cases of disease caused by the Mycobacterium tuberculosis complex. In 2005, a total of 810 cases were identified by bacteriology; an annual reporting rate of 4.0 cases per 100,000 population. Isolates were identified as M. tuberculosis (n = 806), Mycobacterium africanum (n = 2) and Mycobacterium bovis (n = 2). Fifteen children aged under 10 years had bacteriologically-confirmed tuberculosis. Results of in vitro drug susceptibility testing were available for all 810 isolates for isoniazid (H), rifampicin (R), ethambutol (E), and pyrazinamide (Z). A total of 74 (9.1%) isolates of M. tuberculosis were resistant to at least one of these anti-tuberculosis agents. Resistance to at least H and R (defined as multi-drug resistance, MDR) was detected in 12 (1.5%) isolates; nine were from the respiratory tract (sputum n = 8, bronchoscopy n = 1). Of the 74 M. tuberculosis isolates resistant to at least one of the standard drugs, 67 (90.5%) were from new cases, 6 from previously treated cases, and no information was available on the remaining case. Eight were Australian-born, 65 were overseas-born, and the country of birth of one was unknown. Of the 65 overseas-born persons with drug resistant disease, 41 (63.1%) were from 4 countries; Vietnam (n = 16), Papua New Guinea (n = 10), the Philippines (n = 9), and India (n = 6). A retrospective review of AMRLN data on isolates collected between 2000 and 2005 found that none of 70 MDR-TB isolates met the new definition for extensively drug resistant TB (XDR-TB, i.e. MDR-TB with additional resistance to quinolones and second-line injectable agents).

Development and application of two multiplex real-time PCR assays for the detection of Mycobacterium ulcerans in clinical and environmental samples.

Mycobacterium ulcerans is a slow-growing environmental bacterium that causes a severe skin disease known as Buruli ulcer. PCR has become a reliable and rapid method for the diagnosis of M. ulcerans infection in humans and has been used for the detection of M. ulcerans in the environment. This paper describes the development of a TaqMan assay targeting IS2404 multiplexed with an internal positive control to monitor inhibition with a detection limit of less than 1 genome equivalent of DNA. The assay improves the turnaround time for diagnosis and replaces conventional gel-based PCR as the routine method for laboratory confirmation of M. ulcerans infection in Victoria, Australia. Following analysis of 415 clinical specimens, the new test demonstrated 100% sensitivity and specificity compared with culture. Another multiplex TaqMan assay targeting IS2606 and the ketoreductase-B domain of the M. ulcerans mycolactone polyketide synthase genes was designed to augment the specificity of the IS2404 PCR for the analysis of a variety of environmental samples. Assaying for these three targets enabled the detection of M. ulcerans DNA in soil, sediment, and mosquito extracts collected from an area of endemicity for Buruli ulcer in Victoria with a high degree of confidence. Final confirmation was obtained by the detection and sequencing of variable-number tandem repeat (VNTR) locus 9, which matched the VNTR locus 9 sequence obtained from the clinical isolates in this region. This suite of new methods is enabling rapid progress in the understanding of the ecology of this important human pathogen.

Tuberculosis in Australia: bacteriologically confirmed cases and drug resistance, 2004: a report of the Australian Mycobacterium Reference Laboratory Network.

The Australian Mycobacterium Reference Laboratory Network collected and analysed laboratory data on new cases of disease caused by Mycobacterium tuberculosis complex in the year 2004. A total of 787 cases were identified by bacteriology, representing an annual reporting rate of 3.9 cases per 100,000 population. Almost all isolates were identified as M. tuberculosis (n = 785), the remaining isolates being one each of Mycobacterium africanum and Mycobacterium canettii. Seven children under 10 years of age (female n = 5, male n = 2) had bacteriologically confirmed tuberculosis (gastric aspirate n = 4, lymph node n = 1, pleural n = 1, thigh wound n = 1). Results of in vitro drug susceptibility testing were available for all 787 isolates for isoniazid (H), rifampicin (R), ethambutol (E), and pyrazinamide (Z). A total of 71 (9.0%) isolates of M. tuberculosis were resistant to at least one of these anti-tuberculosis agents. Resistance to at least both H and R (defined as multidrug resistance) was detected in 12 (1.5%) isolates; 10 were from the respiratory tract (sputum n = 7, bronchoscopy n = 3). The country of birth was known for 68/71 (95.8%) cases with a drug resistant strain; eight were Australian, 60 were overseas born, and three were unknown. Of the 60 migrants with drug resistant disease, 37 (61.7%) were from three countries; Viet Nam (n = 20), China (n = 9) and India (n = 8).

Molecular characterization of isoniazid-resistant Mycobacterium tuberculosis isolates collected in Australia.

Elucidation of the molecular basis of isoniazid (INH) resistance in Mycobacterium tuberculosis has led to the development of different genotypic approaches for the rapid detection of INH resistance in clinical isolates. Mutations in katG, in particular the S315T substitution, are responsible for INH resistance in a large proportion of tuberculosis cases. However, the frequency of the katG S315T substitution varies with population samples. In this study, 52 epidemiologically unrelated clinical INH-resistant M. tuberculosis isolates collected in Australia were screened for mutations at katG codon 315 and the fabG1-inhA regulatory region. Importantly, 52 INH-sensitive isolates, selected to reflect the geographic and genotypic diversity of the isolates, were also included for comparison. The katG S315T substitution and fabG1-inhA -15 C-to-T mutation were identified in 34 and 13 of the 52 INH-resistant isolates, respectively, and none of the INH-sensitive isolates. Three novel katG mutations, D117A, M257I, and G491C, were identified in three INH-resistant strains with a wild-type katG codon 315, fabG1-inhA regulatory region, and inhA structural gene. When analyzed for possible associations between resistance mechanisms, resistance phenotype, and genotypic groups, it was found that neither the katG S315T nor fabG1-inhA -15 C-to-T mutation clustered with any one genotypic group, but that the -15 C-to-T substitution was associated with isolates with intermediate INH resistance and isolates coresistant to ethionamide. In total, 90.4% of unrelated INH-resistant isolates could be identified by analysis of just two loci: katG315 and the fabG1-inhA regulatory region.

Tuberculosis in Australia: bacteriologically confirmed cases and drug resistance, 2003. A report of the Australian Mycobacterium Reference Laboratory Network.

The Australian Mycobacterium Reference Laboratory Network collected and analysed laboratory data on new cases of disease caused by Mycobacterium tuberculosis complex in the year 2003. A total of 784 cases were identified by bacteriology, representing an annual reporting rate of 3.9 cases of laboratory confirmed tuberculosis per 100,000 population. The most commonly encountered culture-positive specimens were sputum (n = 351), lymph node (n = 176) and from bronchoscopy (n = 97). Smears containing acid fast bacilli were present in sputum (53.0%), bronchoscopy (32.0%) and lymph node (23.3%). Five children (female n = 3, male n = 2) under 10 years of age had bacteriologically confirmed tuberculosis. Eighty isolates of M. tuberculosis and one of Mycobacterium africanum (10.3%) were resistant to at least one of the standard anti-tuberculosis agents. Mono-resistance to isoniazid, ethambutol, rifampicin, and pyrazinamide was detected in 45, three, two, and one isolates respectively. Multidrug-resistance (MDRTB) defined as resistance to both isoniazid and rifampcin was observed in seven (0.9%) isolates. Of the seven MDRTB isolates, six were from the respiratory tract and four were from smear positive specimens. Of the 81 patients with drug resistant isolates, 78 (96.3%) were classified as having initial resistance; two had acquired resistance and no information was available for one isolate; five were Australian-born; and 76 (93.8%) had migrated from a total of 30 countries.

Tuberculosis in Australia: bacteriologically confirmed cases and drug resistance, 2001.

The Australian Mycobacterium Reference Laboratory Network collected and analysed laboratory data on new cases of disease caused by Mycobacterium tuberculosis complex in the year 2001. A total of 771 cases were identified, representing an annual reporting rate of 4.0 cases of laboratory-confirmed tuberculosis per 100,000 population. The predominant specimen type was sputum, (n=369) and a further 111 were collected at bronchoscopy. Smears were positive for 214 of 369 (58.0%) sputum and 42 of 111 (37.8%) bronchoscopy specimens respectively. Seven children (male n=5, female n=2) under 10 years of age had bacteriologically confirmed tuberculosis. A total of 69 isolates (8.9%), comprising 67 M. tuberculosis, one M. africanum, and one M. bovis, were resistant to at least one of the anti-tuberculosis agents. Excluding the M. bovis isolate, 61 of 64 (93.5%) were classified as having initial resistance, three had acquired resistance, and no data were available on the presence or absence of previous treatment for four patients. Resistance to at least isoniazid and/or rifampicin was noted for 67 isolates (8.7%), with resistance to both isoniazid and rifampicin (i.e. defined as multidrug-resistant disease) observed in 12 (1.6%) isolates. All of the multidrug-resistant isolates were M. tuberculosis, 10 were from the respiratory tract. The country of birth was known for 63 of 68 (92.6%) patients with a drug-resistant strain of M. tuberculosis or M. africanum; five were Australian-born and 58 (92.1%) had migrated from a total of 22 countries. One hundred and seven respiratory specimens had a nucleic acid amplification testing performed; 89 of 90 (98.9%) smear positives were nucleic acid amplification testing positive, whilst only 13 of 17 (76.5%) smear negative specimens were nucleic acid amplification testing positive. The 2001 laboratory data reveals a stable incidence rate and level of drug resistance in isolates from Australian patients with tuberculosis.

Tuberculosis in Australia: bacteriologically confirmed cases and drug resistance, 2002: a report of the Australian Mycobacterium Reference Laboratory Network.

The Australian Mycobacterium Reference Laboratory Network collected and analysed laboratory data on new cases of disease caused by Mycobacterium tuberculosis complex in the year 2002. A total of 712 cases were identified by bacteriology, representing an annual reporting rate of 3.6 cases of laboratory-confirmed tuberculosis per 100,000 population. The most commonly encountered culture-positive specimens were sputum (n=325), lymph node (n=142) and bronchoscopy (n=100). Smears containing acid fast bacilli were present in sputum (53.2%), bronchoscopy (37.9%) and lymph node (21.2%). Eight children (male n=3, female n=5) under 10 years of age had bacteriologically-confirmed tuberculosis. A total of 55 isolates (7.7%) of M. tuberculosis were resistant to at least one of the standard anti-tuberculosis agents. Resistance to at least isoniazid and/or rifampicin was noted for 53 isolates (7.4%), with multidrug-resistance (MDRTB) observed in 12 (1.9%) isolates. Of the 12 MDRTB isolates, eight were from the respiratory tract and five were from smear positive specimens. Of the patients with drug resistant M. tuberculosis isolates, 51/55 (92.7%) were classified as having initial resistance, none had acquired resistance during treatment in Australia. The country of birth was known for 54 of 55 such patients; four were Australian-born, and 50 (90.9%) had migrated from a total of 17 countries. Nucleic acid amplification testing (NAAT) was performed on 139 (19.5%) of the 712 culture-positive specimens. Of smear positive respiratory specimens, 74/80 (92.5%) were NAAT positive. For smear negative respiratory specimens, 12/17 (70.6%) reported a NAAT positive result. Importantly, false-negative NAAT results were obtained from 1/16 and 5/64 of smear positive bronchoscopy and sputum specimens respectively.

Tuberculosis in Australia: bacteriologically confirmed cases and drug resistance, 2000: report of the Australian Mycobacterium Laboratory Reference Network.

The Australian Mycobacterium Reference Laboratory Network collected and analysed laboratory data on new diagnoses of disease caused by Mycobacterium tuberculosis complex in the year 2000. A total of 765 cases were identified, representing an annual reporting rate of 4.0 cases of laboratory-confirmed tuberculosis (TB) per 100,000 population. Pulmonary disease was diagnosed in 64.9 per cent of cases with a male:female ratio of 1.5:1. Smears were positive for 209/365 (57.3%) of sputum isolates and 39/117 (33.3%) bronchoscopy isolates. Sputum from males was more likely to be smear-positive (63.3%) than from females (47.5%). Isolates from lymph node accounted for 136 (17.7%) of all cases; only 28.7 per cent were smear-positive. Eighty-four (11.0%) isolates, comprising 82 M. tuberculosis and 2 M. bovis strains, demonstrated in vitro resistance to at least one of the standard anti-TB medications. Resistance to at least isoniazid and rifampicin (defined as multidrug-resistant TB) was observed for only 8 (1.0%) strains, a rate similar to previous years. Almost all (96.3%) of patients with drug resistant strains were classified as having initial resistance. The country of birth was known for 76 (92.7%) of 82 patients with a drug resistant strain of M. tuberculosis; 6 were Australian-born and 70 (92.1%) had migrated from a total of 17 countries. Of these 70 migrants with drug-resistant disease, 68.6 per cent had migrated from one of the following countries: Vietnam (n=15), China (n=11), Philippines (n=11), India (n=6), and Indonesia (n=5).