Epidemiology of antituberculosis drug resistance 2002-07: an updated analysis of the Global Project on Anti-Tuberculosis Drug Resistance Surveillance

BACKGROUND

The Global Project on Anti-Tuberculosis Drug Resistance has been gathering data since 1994. This study provides the latest data on the extent of drug resistance worldwide.

METHODS

Data for drug susceptibility were gathered from 90 726 patients in 83 countries and territories between 2002 and 2007. Standardised collection of results enabled comparison both between and within countries. Where possible, data for HIV status and resistance to second-line drugs were also obtained. Laboratory data were quality assured by the Supranational Tuberculosis Reference Laboratory Network.

FINDINGS

The median prevalence of resistance to any drug in new cases of tuberculosis was 11.1% (IQR 7.0-22.3). The prevalence of multidrug resistance in new tuberculosis cases ranged from 0% in eight countries to 7% in two provinces in China, 11.1% in Northern Mariana Islands (although reporting only two cases), and between 6.8% and 22.3% in nine countries of the former Soviet Union, including 19.4% in Moldova and 22.3% in Baku, Azerbaijan (median for countries surveyed 1.6%, IQR 0.6-3.9). Trend analysis showed that between 1994 and 2007, the prevalence of multidrug-resistant (MDR) tuberculosis in new cases increased substantially in South Korea and in Tomsk Oblast and Orel Oblast, Russia, but was stable in Estonia and Latvia. The prevalence of MDR tuberculosis in all tuberculosis cases decreased in Hong Kong and the USA. 37 countries and territories reported representative data on extensively drug-resistant (XDR) tuberculosis. Five countries, all from the former Soviet Union, reported 25 cases or more of XDR tuberculosis each, with prevalence among MDR-tuberculosis cases ranging between 6.6% and 23.7%.

INTERPRETATION

MDR tuberculosis remains a threat to tuberculosis control in provinces in China and countries of the former Soviet Union. Data on drug resistance are unavailable in many countries, especially in Africa, emphasising the need to develop easier methods for surveillance of resistance in tuberculosis.

FUNDING

Global Project: United States Agency for International Development and Eli Lilly and Company. Drug resistance surveys: national tuberculosis programmes, the Government of the Netherlands, the Global Fund to Fight AIDS, Tuberculosis and Malaria, Japan International Cooperation Agency, and Kreditanstalt für Wiederaufbau.

Direct susceptibility testing for multi drug resistant tuberculosis: a meta-analysis

BACKGROUND

One of the challenges facing the tuberculosis (TB) control programmes in resource-limited settings is lack of rapid techniques for detection of drug resistant TB, particularly multi drug resistant tuberculosis (MDR TB). Results obtained with the conventional indirect susceptibility testing methods come too late to influence a timely decision on patient management. More rapid tests directly applied on sputum samples are needed. This study compared the sensitivity, specificity and time to results of four direct drug susceptibility testing tests with the conventional indirect testing for detection of resistance to rifampicin and isoniazid in M. tuberculosis. The four direct tests included two in-house phenotypic assays - Nitrate Reductase Assay (NRA) and Microscopic Observation Drug Susceptibility (MODS), and two commercially available tests - Genotype MTBDR and Genotype MTBDRplus (Hain Life Sciences, Nehren, Germany).

METHODS

A literature review and meta-analysis of study reports was performed. The Meta-Disc software was used to analyse the reports and tests for sensitivity, specificity, and area under the summary receiver operating characteristic (sROC) curves. Heterogeneity in accuracy estimates was tested with the Spearman correlation coefficient and Chi-square.

RESULTS

Eighteen direct DST reports were analysed: NRA - 4, MODS- 6, Genotype MTBDR - 3 and Genotype MTBDRplus - 5. The pooled sensitivity and specificity for detection of resistance to rifampicin were 99% and 100% with NRA, 96% and 96% with MODS, 99% and 98% with Genotype MTBDR, and 99% and 99% with the new Genotype MTBDRplus, respectively. For isoniazid it was 94% and 100% for NRA, 92% and 96% for MODS, 71% and 100% for Genotype MTBDR, and 96% and 100% with the Genotype MTBDRplus, respectively. The area under the summary receiver operating characteristic (sROC) curves was in ranges of 0.98 to 1.00 for all the four tests. Molecular tests were completed in 1 - 2 days and also the phenotypic assays were much more rapid than conventional testing.

CONCLUSION

Direct testing of rifampicin and isoniazid resistance in M. tuberculosis was found to be highly sensitive and specific, and allows prompt detection of MDR TB.

Drug resistance and genotypic analysis of Mycobacterium tuberculosis strains from Thai tuberculosis patients

The aim of this study was the molecular characterization of primary drug-resistant Mycobacterium tuberculosis strains in Thailand. We examined a group of M. tuberculosis isolates from newly registered tuberculosis (TB) cases, collected at the largest university hospital, the Siriraj Hospital, in Thailand. Of 76 selected drug-resistant M. tuberculosis strains recovered from previously untreated pulmonary TB patients whose sputum samples were sent to this hospital, 29 (38%) were single-drug resistant, 26(34%) multidrug resistant and two (2.6%) extensively drug resistant. Fifty (66%) strains belonged to Beijing genotype. The study demonstrated a severe problem of drug resistance among recently detected TB patients, and two large clusters of genetically similar strains indicated ongoing transmission of drug-resistant TB.

Prevalence of multidrug-resistant pulmonary tuberculosis in counties with different duration of DOTS implementation in rural China

AIMS

This study aimed to describe the prevalence of drug-resistant tuberculosis (TB) among pulmonary TB patients in rural China and to determine the extent of multidrug-resistant TB (MDR-TB) circulating in areas with varied duration of Directly Observed Treatment, Short Course (DOTS) implementation.

METHODS

A cross-sectional study was conducted in two rural counties in eastern China: Deqing with over 10 years' DOTS implementation and Guanyun under its second year of DOTS. The subjects were all culture-positive pulmonary TB patients newly diagnosed or re-treated during 12 months of 2004-2005. The proportion method was used for drug susceptibility testing.

RESULTS

Among the 399 subjects, 283 were new TB cases and 116 were previously treated. The rates of overall resistance (i.e., resistance to at least one drug) in new cases were 50.4% (67) and 63.4% (95), respectively, in Deqing and Guanyun (p = 0.028), and 67.3% (33) and 83.6% (56), respectively, in previously treated cases (p = 0.0410). The rates of MDR-TB in new cases were 3.8% (5) in Deqing and 14.7% (22) in Guanyun (p = 0.0018), and 16.3% (8) and 34.3% (23) in previously treated cases (p = 0.0305).

CONCLUSIONS

Newly diagnosed and previously treated TB patients from the short-term DOTS-covered county were at higher risk for overall drug-resistance TB and MDR-TB. Standardized diagnosis and treatment strategies for drug-resistant TB are urgently needed for effective control of MDR-TB in rural China.

Romanian anti-TB drugs resistance surveillance 2003-2004

Romania decided and initiated a DRS for anti-TB drugs at national level using the standardized methodology proposed by WHO and IUATLD. The DRS protocol was designed with technical assistance from WHO; the surveillance started in June 2003 and ended in June 2004. It was tested the susceptibility to the 4 first line anti-TB drugs: Isoniazide (H), Rifampicin (R), Streptomycin (S), Ethambutol (E). Drug susceptibility testing used: indirect absolute concentration method. There were included in the survey 1251 TB patients from the 60 clusters: 869 new cases and 382 previously treated. From the penitentiary system were included 85 TB patients, 47 new cases and 38 previously treated.

RESULTS

[table: see text]. Estimations of the trend of anti-TB drug resistance in Romania for the next period was proposed.

The nitrate reductase assay for the rapid detection of isoniazid and rifampicin resistance in Mycobacterium tuberculosis: a systematic review and meta-analysis

OBJECTIVES

The reference standard methods for drug susceptibility testing (DST) of M. tuberculosis are very slow to give results, and due to the emergence of multidrug-resistant tuberculosis (MDR-TB) and extensively drug-resistant tuberculosis, there is an urgent demand for new, rapid and accurate DST methods, particularly in low-income countries. The nitrate reductase assay (NRA) has been proposed as a rapid method for the detection of resistance to rifampicin and isoniazid, but its accuracy has not been systematically evaluated.

METHODS

We performed a systematic review and meta-analysis to evaluate the accuracy of the NRA for the detection of rifampicin- and isoniazid-resistant tuberculosis. We searched Medline PubMed (NCBI), Global Health-CAB, EJS-E (EbscoHost), ISI Web, Web of Science and IFCC and contacted authors if additional information was required. Fifteen studies met our inclusion criteria for rifampicin resistance detection and 13 for isoniazid. Of these, the majority of the studies used culture isolates on solid medium, four used culture isolates on liquid medium and three used sputum samples. We applied the summary receiver operating characteristic (SROC) curve to perform meta-analysis and to summarize diagnostic accuracy.

RESULTS

For rifampicin, the majority of the studies that applied NRA to isolates had a sensitivity and specificity >94% and for isoniazid, >92%. The three studies that applied NRA directly on sputum samples had a sensitivity and specificity that ranged between 88% and 100%. The SROC curve had an area of >0.99 for both drugs.

CONCLUSIONS

There is evidence that NRA is highly sensitive and specific for the rapid detection of rifampicin and isoniazid resistance in culture isolates. More evidence is required for the NRA applied directly on sputum samples, but preliminary results appear promising and show a good sensitivity and specificity. Additional studies are required in countries with a high prevalence of MDR-TB and also cost-effectiveness analysis in order to obtain a complete picture on the utility of this method for rapid drug resistance detection in tuberculosis.

Molecular epidemiology of drug-resistant tuberculosis in Sweden

Drug-resistant tuberculosis (TB), including the more severe forms of multidrug- and extensively drug-resistant forms, is an increasing public health concern globally. In Sweden the majority of patients with TB are immigrants from countries with a high incidence of TB including the drug-resistant forms. In this study, the spread of resistant TB in Sweden was investigated by molecular fingerprinting. Isolates resistant to at least one of the drugs, isoniazid, rifampicin, ethambutol or streptomycin, from 400 patients collected between 1994 and 2005, were studied by restriction fragment length polymorphism (RFLP) and by spoligotyping. Thirty-five clusters of patients infected with strains with identical RFLP and spoligotyping patterns (2-96 patients per cluster), comprising a total of 203 patients, were found. One large outbreak of isoniazid resistant tuberculosis was identified, involving 96 patients, mainly from the Horn of Africa. To identify chains of transmission, molecular epidemiological characterization of TB isolates should, if possible, be performed on isolates from all new TB patients.

The added value of a European Union tuberculosis reference laboratory network – analysis of the national reference laboratory activities

National reference laboratories (NRL) and other laboratories are the cornerstones of well-functioning tuberculosis programmes and surveillance activities. However, the scope and activity of NRL services for mycobacterial identification and drug susceptibility testing (DST) has not been examined in detail across the European Union (EU), nor has the added value of cooperation and networking at the European level been explored with regard to strengthening laboratory services. Therefore, the European Centre for Disease Prevention and Control (ECDC) has commissioned a survey to explore these issues and to identify areas of work that could bring added value by supporting networking activities of tuberculosis (TB) reference laboratories in the EU. Structured questionnaires were sent to TB reference laboratory experts in the EU and European Economic Area (EEA) countries, and in three additional countries selected on the basis of their networking activities with EU projects and other initiatives (Switzerland, Croatia and Israel). The compiled results describe the activities and structure of 32 NRLs (29 countries replied, a response rate of 91%). The analysis of the survey led to the following recommendations for strengthening TB laboratory services: (1) implementing of the published European standards for TB laboratory services with respect to infrastructure, national reference functions, biosafety, human resources, quality assurance, operational research (including evaluation of new medical diagnostics), accuracy and speed, appropriately trained staff; (2) ensuring that laboratories only perform activities for which they have demonstrated proficiency; (3) implement validated and standardised second-line drug susceptibility testing (DST), including drugs used to define extensively drug-resistant tuberculosis (XDR TB); (4) aiming to identify Mycobacterium tuberculosis complex (MTBC) and rifampicin (RIF) resistance in over 90% of cultures and cases from smear-positive sputum directly within one to two working days. To realise some of the above recommendations and to strengthen links of TB surveillance and microbiology activities in the EU, a list of suggested generic areas of activities for an EU network of reference laboratories is presented. Such a network would build on and link to existing networks and initiatives at the European and global level.

Antimicrobial susceptibility testing of Mycobacterium tuberculosis (EUCAST document E.DEF 8.1)--report of the Subcommittee on Antimicrobial Susceptibility Testing of Mycobacterium tuberculosis of the European Committee for Antimicrobial Susceptibility Testing (EUCAST) of the European Society of Clinical Microbiology and Infectious Diseases (ESCMID)

This review describes the methods available for drug susceptibility testing of Mycobacterium tuberculosis. The methods have been developed over several decades and are restricted to specialised centres in most European countries, as they are technically demanding, require appropriate isolation facilities and can be difficult to interpret. The absolute concentration, resistance ratio and proportion methods can all give accurate results, provided that they are carefully quality-controlled and standardised. Automated rapid culture and molecular methods have been evaluated at large reference centres and in multicentre collaborations, and perform well for testing susceptibility to most first- and second-line anti-tuberculosis drugs. Accuracy is more important than rapid testing, and this is most reliably achieved if drug susceptibility tests are done in a small number of well-equipped, experienced laboratories that participate and perform well in an international drug susceptibility testing quality assessment scheme. The WHO Supranational Laboratory Quality Control Network offers a global scheme that assesses the ability of participating laboratories to identify isoniazid, rifampicin, ethambutol and streptomycin resistance. Second-line drug resistance testing is currently being standardised, and such testing should only be performed at the national reference laboratories in western and central European countries because of the relatively small number of cases and the concomitant difficulty of maintaining testing proficiency in multiple centres performing small numbers of tests. There is a need to expand international external quality assessment to include second-line drug susceptibility testing.

Resistance levels and rpoB gene mutations among in vitro-selected rifampin-resistant Mycobacterium tuberculosis mutants

The distribution and resistance levels of 189 in vitro-selected rifampin-resistant Mycobacterium tuberculosis mutants of Beijing and other genotypes were determined. Apart from a higher amount of codon 522 point mutations and large deletions, a spread of mutations similar to that reported for clinical isolates was seen. Most mutations were correlated with high-level resistance; a lower level, or a MIC of <16 mg/liter, was associated with codon 522 mutations. Multiple mutations were detected in two Beijing mutants.

Extensively drug-resistant tuberculosis: 2 years of surveillance in Iran

BACKGROUND

Extensively drug-resistant (XDR) tuberculosis (TB) is a cause of concern, because it renders patients untreatable with available drugs. In this study, we documented the existence and transmission of XDR TB among patients with multidrug-resistant TB. These patients were referred to the National Research Institute of Tuberculosis and Lung Diseases (Tehran, Iran) for treatment and diagnosis from 2003 to 2005.

METHODS

The sputum specimens from a total of 2030 patients with TB were digested, examined microscopically for acid-fast bacilli, and inoculated into Lowenstein-Jensen slants by standard procedures. Testing of susceptibility to first-line drugs was performed for 1284 Mycobacterium tuberculosis isolates. Subsequently, the strains that were identified as multidrug-resistant M. tuberculosis (113 isolates) were subjected to susceptibility testing for second-line drugs. Spoligotyping and restriction fragment-length polymorphism were performed for strains that were identified as XDR M. tuberculosis.

RESULTS

A total of 12 (10.9%) of 113 multidrug-resistant M. tuberculosis strains were resistant to all 8 second-line drugs tested and, therefore, were denoted as XDR M. tuberculosis. Retrospective analysis of the cases of XDR TB showed that all of them belonged to 1 of 2 epidemiological clusters, either a single-family cluster (4 cases) or a cluster of close contacts (8 cases). The strains were identified as belonging to the M. tuberculosis superfamilies Haarlem 1 and East African Indian 3.

CONCLUSIONS

The emergence of XDR TB cases in Iran highlights the need to reinforce the Iranian TB policy with regard to control and detection strategies.

Recommended standards for modern tuberculosis laboratory services in Europe

The principles underpinning these standards are that any tuberculosis laboratory-based diagnostic procedure should be performed by appropriately trained staff, working to standardised operating procedures in appropriately equipped and safe laboratories, against clear national and international proficiency and quality standards. Quality should be the pre-eminent criteria, not cost. The standards are technologically feasible, but initially may not be within the financial capacity of all laboratories. There is a requirement for government and international donors to adequately fund an appropriate safe infrastructure to enable staff to deliver accurate and timely results at whatever level of activity they are performing. There is a need for national reference laboratories to train a new cadre of mycobacterial laboratory experts. This will require the funding of appropriate individuals at these centres to train and assist in the implementation of good laboratory practice and evaluation to build sustainable capacity. Further operational research is needed to establish the optimal configuration of new technologies to determine isoniazid, rifampicin and second-line drug susceptibility in mycobacterial cultures and also, increasingly, directly on specimens. Improved integration of laboratory medicine as a core part of all tuberculosis programmes is needed to achieve and maximise the potential of new developments.

Enhanced susceptibility of multidrug resistant strains of Mycobacterium tuberculosis to granulysin peptides correlates with a reduced fitness phenotype

Previously it was shown that the antimicrobial protein granulysin possesses potent membranolytic activity against Mycobacterium tuberculosis. Here we demonstrate that granF2 and G13, which are two short synthetic peptides derived from granulysin, inhibited the in vitro growth of clinical isolates of both multidrug resistant and drug susceptible strains of M. tuberculosis. Importantly, a particularly high activity against multidrug resistant M. tuberculosis correlated with a reduced growth rate compared to drug susceptible strains. A synergistic antibacterial effect of granF2 was further observed in combination with ethambutol, a compound with a documented effect on cell wall permeability. This finding suggests that granF2 and ethambutol exert their functions at different levels of the mycobacterial surface. Upon infection of macrophages in vitro, granF2 but not G13 efficiently reduced the intracellular growth of multidrug resistant M. tuberculosis in the presence of the pore-forming protein streptolysin O. The apoptotic function of granF2 apparently promoted destruction of host cells whereby the peptide gained access to and killed intracellular bacteria. Thus, a cost of resistance and a subsequent reduced fitness, measured as decreased growth among multidrug resistant strains of M. tuberculosis, could be associated with increased susceptibility to natural immune defense mechanisms, such as antimicrobial peptides of granulysin. However, a robust cell wall and the membrane of cells still provide physical shelter for the bacteria that may spare sensitive M. tuberculosis stains from being killed.

Rhodococcus and Mycobacterium Tuberculosis: masquerade or mixed infection

Rhodocci have a morphology similar to that of Mycobacterium tuberculosis (TB), and are indistinguishable from normal diphtheroid flora. Symptoms include fever, productive/non-productive cough and pleuritic chest pain. Rhodococcal infections, being resistant to routine anti-tuberculosis medications, may be misdiagnosed as drug-resistant TB, thus prompting treatment for TB with rifampicin-containing regimens that promote the emergence of resistance. We present here a sputum smear AFB-positive case who, although clinically cured, remains unresolved despite a series of technological investigations as to the cause of infection being purely rhodococci or mixed infection with M. tuberculosis.

Origin and primary dispersal of the Mycobacterium tuberculosis Beijing genotype: clues from human phylogeography

We suggest that the evolution of the population structure of microbial pathogens is influenced by that of modern humans. Consequently, the timing of hallmark changes in bacterial genomes within the last 100,000 yr may be attempted by comparison with relevant human migrations. Here, we used a lineage within Mycobacterium tuberculosis, a Beijing genotype, as a model and compared its phylogeography with human demography and Y chromosome-based phylogeography. We hypothesize that two key events shaped the early history of the Beijing genotype: (1) its Upper Palaeolithic origin in the Homo sapiens sapiens K-M9 cluster in Central Asia, and (2) primary Neolithic dispersal of the secondary Beijing NTF::IS6110 lineage by Proto-Sino-Tibetan farmers within east Asia (human O-M214/M122 haplogroup). The independent introductions of the Beijing strains from east Asia to northern Eurasia and South Africa were likely historically recent, whereas their differential dissemination within these areas has been influenced by demographic and climatic factors.

Mycobacterium avium with the bird type IS1245 RFLP profile is commonly found in wild and domestic animals, but rarely in humans

Cervical lymphadenitis is the main manifestation of Mycobacterium avium infection in immunocompetent children. Exposure to birds has been discussed as a source of infection. To clarify from where children acquire the infection, M. avium isolates from different origins were analysed with restriction fragment length polymorphism (RFLP) on insertion sequence IS1245, and compared by computer cluster correlation analysis. This molecular epidemiological tool has previously revealed a distinction between multiband profiles found mainly in strains from humans, and a 3-band/bird type profile in strains isolated mainly from birds. 32 isolates from children were compared with 28 isolates from adults and 45 isolates from animals. We found that 67% of the animal isolates had the bird type profile, also found in 1 sputum isolate from an adult. Strains from children showed only multiband profiles that did not differ significantly from profiles of isolates from adults. All but 2 bird isolates showed the bird type profile. Neither of the remaining 2, which had multiband profiles, clustered with the isolates from children. Our results indicate that the true reservoir of M. avium is unknown. Thus the question of whether or not M. avium can be incriminated as a zoonotic disease remains unanswered.

A diarylquinoline drug active on the ATP synthase of Mycobacterium tuberculosis

The incidence of tuberculosis has been increasing substantially on a worldwide basis over the past decade, but no tuberculosis-specific drugs have been discovered in 40 years. We identified a diarylquinoline, R207910, that potently inhibits both drug-sensitive and drug-resistant Mycobacterium tuberculosis in vitro (minimum inhibitory concentration 0.06 mug/ml). In mice, R207910 exceeded the bactericidal activities of isoniazid and rifampin by at least 1 log unit. Substitution of drugs included in the World Health Organization's first-line tuberculosis treatment regimen (rifampin, isoniazid, and pyrazinamide) with R207910 accelerated bactericidal activity, leading to complete culture conversion after 2 months of treatment in some combinations. A single dose of R207910 inhibited mycobacterial growth for 1 week. Plasma levels associated with efficacy in mice were well tolerated in healthy human volunteers. Mutants selected in vitro suggest that the drug targets the proton pump of adenosine triphosphate (ATP) synthase.

Drug susceptibility testing of Mycobacterium tuberculosis to fluoroquinolones: first experience with a quality control panel in the Nordic-Baltic collaboration

In the first attempt to establish a quality assurance programme for susceptibility testing of Mycobacterium tuberculosis to fluoroquinolones, 20 strains with different fluoroquinolone susceptibility patterns were distributed by the Supranational Reference Laboratory in Stockholm to the other mycobacterial reference laboratories of the Nordic and Baltic countries. Susceptibility testing to fluoroquinolones was performed according to routine procedures in each laboratory. Results were compared to sequence analysis of the gyrA gene and minimal inhibitory concentration determination. Most laboratories found identical susceptibility patterns. The two resistant strains were correctly identified by all laboratories, but three laboratories each falsely reported one susceptible strain as resistant. These results indicate that the participating laboratories yield reliable results in detection of fluoroquinolone-resistant strains, although the need for a standardised quality assurance programme for drug susceptibility testing for fluoroquinolones is stressed by the strains falsely reported as resistant.

Discordant resistance to kanamycin and amikacin in drug-resistant Mycobacterium tuberculosis

It is generally thought that there is full cross-resistance in Mycobacterium tuberculosis between the aminoglycoside drugs kanamycin and amikacin. However, kanamycin resistance and amikacin susceptibility were seen in 43 of 79 (54%) multidrug-resistant Estonian isolates, indicating that there might be a need to test the resistance of M. tuberculosis isolates to both drugs.

Measurement of gastric emptying by 13C-octanoic acid breath test versus scintigraphy in diabetics

In this prospective study, we compared the assessment of gastric emptying by the 13C-octanoic acid breath test to gastric emptying scintigraphy in diabetics. We also examined the relationship between gastric emptying parameters and gastric symptoms and cardiovascular autonomic function. The 13C-octanoic acid breath test and scintigraphy were performed simultaneously in 24 diabetics with a solid test meal (1 egg, doubly labelled with 91 mg 13C-octanoic acid and 50 MBq 99mTechnetium-Nanocoll, 60 g white bread, 5 g margarine and 150 ml water). At fifteen-minute intervals, breath samples were taken over 4 hours and examined by mass spectrometry. In parallel, scintigraphy was performed for 2 hours at one minute intervals. Using breath test data, gastric emptying half time (t (1/2) ), lag-phase (t lag ) and gastric emptying coefficient (GEC) were calculated. Subsequently, the correlation of these results with the equivalent data from scintigraphy were determined employing a regression method. To detect a cardiovascular autonomic neuropathy, a 24-h ECG recording was performed. The prevalence of gastrointestinal symptoms in our collective was assessed by a standardized questionnaire. There was a highly significant positive correlation of both 13C-octanoic acid breath test t (1/2) and scintigraphic t (1/2) (r = 0.8257; p < 0.0001) and 13C-octanoic acid breath test t lag and scintigraphic t lag (r = 0.6302; p < 0.001). The sensitivity of the 13C-octanoic acid breath test was 1 and the specificity was 0.73. In our study, there was no significant association of cardiovascular and gastrointestinal autonomic neuropathy. Furthermore, there was no significant relationship between the prevalence of gastrointestinal symptoms and gastric emptying disorders. We conclude that the 13C-octanoic acid breath test represents a suitable method to measure disordered gastric emptying in diabetics due to its highly significant positive correlation to scintigraphy and due to its validity. It is not possible to predict diabetic gastroparesis on the basis of other autonomic function disorders or because of dyspeptic symptoms.

[Diagnosis of hyperparathyroidism]

AIM

To preoperatively localize enlarged parathyroid glands in patients with hyperparathyroidism (HPT).

METHODS

Besides clinical and biochemical workup, high-resolution ultrasonography (US) is the most commonly used imaging method.Additionally,Tc-99m-MIBI scintigraphy in subtraction or biphasic technique, computed tomography (CT) and magnetic resonance imaging (MRI) are used.

RESULTS

US fails to detect a minimum of 10% of enlarged parathyroid glands,most commonly due to ectopic location, or difficult examination conditions, such as nodular goiter or previous surgery. If attempted US localization is unsuccessful, multiphase scintigraphy, using Tc-99m-sestamibi, can help to locate ectopic adenomas in the mediastinum. With SPECT, ademomas can be found which escape detection on planar scans due to their small size. With combined use of US and scintigraphy, a correct localization of parathyroid adenomas is possible in up to 90%. CT and MRI are of limited value due to their low specificity.

CONCLUSION

For newly diagnosed hyperparathyroidism, high-resolution US is the method of choice for localizing parathyroid adenomas. If ultrasound fails to detect a lesion, Tc-99m-MIBI scintigraphy is recommended. In patients scheduled for re-operation for recurrent or persistent HPT, a preoperative detection of a parathyroid adenoma should be attempted whenever possible, in order to minimize the extent of surgery. The role of CT or MRI is mainly to help to better anatomically localize a suspected adenoma previously detected with scintigraphy.

[Resistant tuberculosis is spreading in Sweden. Molecular epidemiological strain identification by "fingerprinting" can make the infection tracing easier]

Resistance of Mycobacterium tuberculosis to antibiotics is a world wide problem. A study is reported with the aim to analyse the spread of resistant isolates of M tuberculosis complex from patients with tuberculosis in Sweden. The study is based on a sample of 192 M tuberculosis complex isolates from patients with drug resistant tuberculosis during 1994-2000. All isolates resistant to at least one of the drugs streptomycin, isoniazid, ethambutol and rifampicin were included in the study. Restriction fragment length polymorphism (RFLP) was performed, using IS6110 as a probe for hybridisation. Visualised bands were analysed by Gel Compar software. The majority of the isolates were from patients born in high TB prevalence countries. During the years 1996-2000 there was one major cluster generated from 34 isolates. In 1996-1998 there were two isolates per year, in 1999 it increased to 20 isolates, and eight cases in 2000. All strains were resistant to isoniazid. All patients in this cluster were found to be from Africa. In comparing the pattern in the T-base the strains matched with strain BEA-000007341 isolated from a patient in Rwanda. The majority of patients with drug resistant tuberculosis in Sweden are immigrants from countries with high incidence of tuberculosis. Spread of disease to the Swedish born population is uncommon. However, an increasingly prevalent clone of isoniazid resistant tuberculosis was found among African immigrants, mainly living in the Stockholm area.