Evaluating the Sensitivity of Different Molecular Techniques for Detecting Mycobacterium tuberculosis Complex in Patients with Pulmonary Infection.

This study aimed to evaluate the accuracy of detecting drug-resistant Mycobacterium tuberculosis complex (MTBC)-specific DNA in sputum specimens from 48 patients diagnosed with pulmonary tuberculosis. The presence of MTBC DNA in the specimens was validated using the GeneXpert MTB/RIF system and compared with a specific PCR assay targeting the IS6110 and the mtp40 gene sequence fragments. Additionally, the results obtained by multiplex PCR assays to detect the most frequently encountered rifampin, isoniazid, and ethambutol resistance-conferring mutations were matched with those obtained by GeneXpert and phenotypic culture-based drug susceptibility tests. Of the 48 sputum samples, 25 were positive for MTBC using the GeneXpert MTB/RIF test. Nevertheless, the IS6110 and mtp40 single-step PCR revealed the IS6110 in 27 of the 48 sputum samples, while the mtp40 gene fragment was found in only 17 of them. Furthermore, multiplex PCR assays detected drug-resistant conferring mutations in 21 (77.8%) of the 27 samples with confirmed MTBC DNA, 10 of which contained single drug-resistant conferring mutations towards ethambutol and two towards rifampin, and the remaining nine contained double-resistant mutations for ethambutol and rifampin. In contrast, only five sputum specimens (18.5%) contained drug-resistant MTBC isolates, and two contained mono-drug-resistant MTBC species toward ethambutol and rifampin, respectively, and the remaining three were designated as multi-drug resistant toward both drugs using GeneXpert and phenotypic culture-based drug susceptibility tests. Such discrepancies in the results emphasize the need to develop novel molecular tests that associate with phenotypic non-DNA-based assays to improve the detection of drug-resistant isolates in clinical specimens in future studies.

An Elderly COVID-19 Patient with Community-Acquired Legionella and Mycoplasma Coinfections: A Rare Case Report.

The combination of severe acute respiratory syndrome corona virus-2 (SARS-CoV-2) infection and other respiratory pathogens is a real challenge for health care systems in terms of diagnosis, treatment, and management. Most of the reported bacterial coinfections among SARS-CoV-2 patients are hospital-acquired infections that occurred after several days of hospitalization. Little is known about the incidence of community-acquired atypical bacterial coinfections with SARS-CoV-2. In this work, we report on a rare case of an elderly SARS-CoV-2 patient with underdiagnosed bacterial coinfections who received care in the medical ward for 23 days then was discharged home. Retrospective serological investigation revealed positivity for Legionella pneumophila and Mycoplasma pneumoniae, indicating double community-acquired atypical bacterial coinfections that were in agreement with clinical manifestations that patients showed at his admission to the hospital. Screening for possible community-acquired respiratory co-pathogens among elderly SARS-CoV-2 patients is critical for effective treatment and management.