Tuberculosis lymphadenitis in a southeastern region in Tunisia: Epidemiology, clinical features, diagnosis and treatment

To evaluate patients' profiles, demographics, clinical and therapeutic approaches and strategies in patients with tuberculous lymphadenitis [TBG]. A retrospective study of all TBG-confirmed cases admitted in a tuberculosis-specific health care facility between 1 January 2009 and 16 June 2013. A total of 181 clinical files were examined. Mean age was 32 years old; the female/male ratio was 1.78 to 1. Raw milk consumption was noted in 1/3 of patients. Most cases involved the head and neck region [83.4%], nodes involvement, including axillary [12 cases], and mediastinal [9 cases]. Clinical symptoms were present in only 55.2%. Tuberculin skin test [TST] was conducted with 82.6% positive responses. Diagnostics confirmation was done with anatomical pathology in most of the patients; only 56 of them had any microbiology analysis done. Demonstration of acid-fast bacilli in microscopy from either fine-needle aspirates or biopsies was done in 17.5% of cases, and cultures yielded positive results in 27%. Treatment duration was varied. Paradoxical reactions were noted in 12% and persistent lymphadenopathy after treatment completion was noted in 10% of cases. TBG remains a disease of interest. Today, its diagnosis and management is still a problem despite its increasing worldwide incidence, and especially in this study area. Disease control should be strengthened in this country

Drug susceptibility testing of Mycobacterium tuberculosis by a nitrate reductase assay applied directly on microscopy-positive sputum samples

Current methods for drug susceptibility testing [DST] of Mycobacterium tuberculosis [MTB] are either costly or slow. As the prevalence of multidrug-resistant [MDR] strains increases, the need for fast, reliable, and inexpensive methods is obvious. This study evaluated a rapid colorimetric nitrate reductase assay [NRA] for direct DST of MTB directly from clinical sputum samples. A total of 111 sputa with positive microscopy results for acid-fast bacilli [AFB] with more than 10 AFB per high-power field were used in the study. The samples were decontaminated using the modified Petroff method. The NRA results were compared with the reference indirect proportion method. The sensitivity and the specificity of the direct NRA were 90% and 97.3%, 92.6% and 98.2%, 52.9% and 100%, and 28.6% and 100% for rifampin, isoniazid, streptomycin, and ethambutol, respectively. The results were in most cases available in 28 days [84.3%]. The direct NRA could be used as a rapid, inexpensive, and accurate method to determine rifampin and isoniazid susceptibility directly from sputum. The technique might become a valid alternative to traditional methods, especially in low-income countries

Diagnosis of lymph node tuberculosis using the GeneXpert MTB/RIF in Tunisia

Introduction: GeneXpert MTB/RIF is a fully-automated diagnostic molecular test which simultaneously detects tuberculosis [TB] and rifampicin [RIF] drug resistance. The purpose of this study is to evaluate the performance of the GeneXpert MTB/RIF test for the detection of Mycobacterium tuberculosis complex [MTBC] in lymph node specimens and to show the place of Mycobacterium bovis as a major cause of TB lymphadenitis

Material and methods: This study was conducted simultaneously in the National Reference Laboratory for Mycobacteria of Ariana and the Central Laboratory of Sfax, from January to December 2013. In total, 174 lymph node specimens were processed simultaneously for Ziehl-Neelsen, auramine and immuno-histochemical staining. Conventional culture on both Lowenstein-Jensen and liquid medium [Bactec MGIT 960 BD system] and the new molecular-based GeneXpert MTB/RIF assay system were performed. Positive cultures were confirmed using molecular identification [Genotype MTBC Hain Lifescience]

Results: Among the 174 samples tested, the GeneXpert detected the DNA of MTBC in 134 samples [77%]. Standard bacteriological assays, including AFB microscopy and culture, were positive, respectively, in 41 [23.6%] and 79 [45.4%] specimens. M. bovis was isolated in 76% of positive cultures. GeneXpert sensitivity and specificity results were assessed according to smear and culture results, clinical and histological findings. The sensitivity and specificity of the Xpert assay were 87.5% [126/144] and 73.3%, respectively

Conclusion: The implementation of the GeneXpert MTB/RIF assay may dramatically improve the rapid diagnosis of lymph node TB