Detection of Mycobacterium tuberculosis in AFB smear-negative sputum specimens through MTB culture and GeneXpert® MTB/RIF assay

Tuberculosis (TB) is an important public health issue around the globe which is a chronic infectious disease and is still one of the major challenges for developing countries. The emergence of drug-resistant TB makes the condition worse and there is an urgent need of fast, highly sensitive diagnostic methods. This study was undertaken to evaluate the performance of GeneXpert® MTB/RIF assay and MTB culture for the detection of Mycobacterium tuberculosis (MTB) in sputum smear-negative pulmonary TB/drug-resistant tuberculosis (DR-TB) suspects. A total of 168 sputum smear-negative TB suspects were recruited for the study. Among the suspected TB cases, 52.98% were male and 47.02% were females with the mean age of 42 ± 17.6 years. All the sputum specimens collected from the study population were subjected to Ziehl-Neelsen (ZN) smear microscopy, GeneXpert MTB/RIF assay, and MTB culture. The results revealed that, out of 168 acid-fast bacilli (AFB)/ZN smear microscopy-negative sputum specimens, 48 (28.57%) and 58 (34.52%) were detected MTB positive by GeneXpert MTB/RIF assay and MTB culture, respectively, while 120 (71.43%) and 110 (65.48%) suspected TB cases were confirmed negative by GeneXpert MTB/RIF assay and MTB culture, respectively. The study concluded that GeneXpert assay was found to be a rapid and accurate tool for MTB detection in smear-negative sputum specimens. GeneXpert has advantage over ZN smear microscopy and MTB culture as it detects MTB and rifampicin resistance simultaneously within 2 h with minimal biohazards.

Hematological profiling of tuberculosis-infected and co-morbid patients: A study carried out in central Punjab, Pakistan

Tuberculosis (TB) caused by Mycobacterium tuberculosis (MTB) is a chronic bacterial infection affecting many organs of the body particularly the lungs. Another organ seriously affected by TB is the hematopoietic system. TB patients co-infected with other disorders are more prone to death than TB alone. This study was aimed to investigate the variations in hematological profile of pulmonary tuberculosis (PTB) patients co-infected with chronic infectious and metabolic disorders. The study population (n = 366) include PTB patients (positive control) and PTB patients co-infected with hepatitis C virus (HCV) infection, human immunodeficiency virus (HIV) infection, diabetes, and myocardial infarction (MI). Healthy individuals (n = 95) were also included as normal control. All the study subjects were screened for PTB, diabetes, HCV infection, MI, and HIV infection. Polymerase chain reaction (PCR) was performed to confirm MTB infection at molecular level. Among 366 Ziehl–Neelsen positive cases, 258 (70.5%) were confirmed PTB positive by PCR. Among them, 36.8% were infected with PTB only, while 24% were co-morbid with diabetes, 17.8% co-infected with HCV, 11.2% with diabetes and HCV, 4.2% with HIV, 2.3% with both HCV and HIV, and 3.4% co-morbid with MI. Significant ( P < 0.01) variations were observed in hematological profile of different study groups. The study concluded that significant increase in PTB patients co-infected with HCV, HIV, diabetes, and MI suggests the investigation of co-morbidities to rule out PTB co-infection with infectious and metabolic disorders before the start of anti-TB drug therapy.