The use of rats to detect drug-resistant TB.

Although detection of drug-susceptible TB by Anti-Persoonsmijnen Ontmijnende Product Ontwikkeling-trained African giant pouched rats has been known for more than a decade, the detection of drug-resistant TB (DR-TB) using rats has never been explored before. We present what we believe to be the first report on rifampicin-resistant TB (RR-TB) detected using Xpert® MTB/RIF Ultra, comparably identified by rats sniffing sputum samples from presumptive TB patients: 88% of RR-TB detected using Ultra were identified by the rats. Further evaluation of the usefulness of rats for large-scale DR-TB contact triage testing is needed, especially in low- and middle-income countries, where resources are limited.

Bien que la détection de la TB pharmacosensible par des rats géants de Gambie dressés par APOPO (Anti-Persoonsmijnen Ontmijnende Product Ontwikkeling) soit connue depuis plus d'une décennie, la détection de la TB pharmacorésistante (DR-TB) à l'aide de rats n'a jamais été explorée auparavant. Nous présentons ce que nous pensons être le premier rapport sur la TB résistante à la rifampicine (RR-TB) détectée par test Xpert® MTB/RIF Ultra, identifiée de manière comparable par des rats reniflant des échantillons d'expectorations de patients avec une TB présumée : 88% des RR-TB détectées par test Ultra ont été identifiées par les rats. L'évaluation de l'utilité des rats dans le cadre de tests de triage des contacts de cas de DR-TB à grande échelle doit être poursuivie, en particulier dans les pays à revenu faible ou intermédiaire, où les ressources sont limitées.

African pouched rats for the detection of pulmonary tuberculosis in sputum samples.

SETTING: Resource-limited settings in sub-Saharan African countries. OBJECTIVE: To utilise African giant pouched rats (Cricetomys gambianus) for the diagnosis of tuberculosis (TB) in human sputum. DESIGN: A specially designed cage with 10 sniffing holes and cassette-carrier was used. The sputum samples were put in the sample cassette, containing 10 samples in line, placed under matching sniffing holes. Rats were trained to sniff each consecutive sample, and indicate TB positives by fixing their nose for 5 seconds at the sniffing hole. This behaviour was maintained by food reinforcement upon correct indications. A total of 3416 samples were used. RESULTS: Of the 20 trained rats, 18 were able to discriminate positive from negative sputum samples, with average daily sensitivities ranging from 72% to 100%, and average daily false-positives ranging from 0.7% to 8.1%. The use of multiple rats significantly increased sensitivity and negative predictive value. CONCLUSION: Utilising trained sniffer rats for TB detection is a potentially faster screening method and is at least as sensitive as smear microscopy. This method could therefore be suitable for active case finding, especially where large numbers of samples are to be analysed in resource-limited settings, to complement existing diagnostic techniques.

Accuracy of giant African pouched rats for diagnosing tuberculosis: comparison with culture and Xpert® MTB/RIF.

SETTING: Enhanced tuberculosis (TB) case finding using detection rats in Tanzania. OBJECTIVES: To assess the diagnostic accuracy of detection rats compared with culture and Xpert® MTB/RIF, and to compare enhanced case-finding algorithms using rats in smear-negative presumptive TB patients. DESIGN: A fully paired diagnostic accuracy study in which sputum of new adult presumptive TB patients in Tanzania was tested using smear microscopy, 11 detection rats, culture and Xpert. RESULTS: Of 771 eligible participants, 345 (45%) were culture-positive for Mycobacterium tuberculosis, and 264 (34%) were human immunodeficiency virus (HIV) positive. The sensitivity of the detection rats was up to 75.1% (95%CI 70.1-79.5) when compared with culture, and up to 81.8% (95%CI 76.0-86.5) when compared with Xpert, which was statistically significantly higher than the sensitivity of smear microscopy. Corresponding specificity was 40.6% (95%CI 35.9-45.5) compared with culture. The accuracy of rat detection was independent of HIV status. Using rats for triage, followed by Xpert, would result in a statistically higher yield than rats followed by light-emitting diode fluorescence microscopy, whereas the number of false-positives would be significantly lower than when using Xpert alone. CONCLUSION: Although detection rats did not meet the accuracy criteria as standalone diagnostic or triage testing for presumptive TB, they have additive value as a triage test for enhanced case finding among smear-negative TB patients if more advanced diagnostics are not available.

[Levels of different metabolites of arachidonic acid in synovial fluid of patients with arthrosis or rheumatoid arthritis]. / Livelli di differenti metaboliti dell'acido arachidonico nel liquido sinoviale di pazienti con artrosi o con artrite reumatoide.

OBJECTIVE: Clinical and experimental evidence suggests that arachidonic acid metabolism through lipoxygenase and cyclooxygenase pathways may play an important role in the pathogenesis of both inflammatory and degenerative joint diseases. The aim of the present paper was to measure the levels of different arachidonate metabolites in arthrosis or rheumatoid joint effusions. MATERIALS AND METHODS: We studied synovial fluids from 22 patients with arthrosis and 8 patients with rheumatoid arthritis. The levels of TxB2, 6-keto-PGF1 alpha LTB4 and LTC4 were measured by radioimmunoassay. RESULTS: The levels of the different arachidonate metabolites were higher in patients with rheumatoid arthritis than in those with arthrosis and the differences were always statistically significant, except for TxB2 values. Furthermore, in patients with arthrosis the levels of such metabolites were not significantly correlated with one another, with the exception of LTB4 and LTC4 values, while in patients with rheumatoid arthritis these levels were directly and significantly correlated. CONCLUSIONS: In inflammatory joint disease levels of arachidonate metabolites are higher and more directly correlated with one another than in degenerative joint disease. Our data may explain the better efficacy of non-steroidal anti-inflammatory drugs in patients with arthrosis than in those with rheumatoid arthritis and the frequent necessity for steroidal treatment in this last condition.