Mammalian cell cultures as models for Mycobacterium tuberculosis-human immunodeficiency virus(HIV) interaction studies:A review

Mycobacterium tuberculosis(MTB) and human immunodeficiency virus(HIV) co-infections have remained a major public health concern worldwide,particularly in Southern Africa.Yet our understanding of the molecular interactions between the pathogens has remained poor,primarily due to lack of suitable preclinical models for such studies.We reviewed the use,this far,of mammalian cell culture models in HIV-MTB interaction studies.Studies have described the use of primary human cell cultures,including monocyte-derived macrophage(MDM) fractions of peripheral blood mononuclear cell(PBMC),alveolar macrophages(AM),cell lines such as the monocyte-derived macrophage cell line(U937),T lymphocyte cell lines(CEMx174,ESAT-6-specific CD4+ T-cells) and an alveolar epithelial cell line(A549) and special models such as stem cells,three dimensional(3D) or organoid cell models [including a blood-brain barrier(BBB) cell model] in HIV-MTB interaction studies.The use of cell cultures from other mammals,including:mouse cell lines [macrophage cell lines RAW 264.7 and J774.2,fibroblast cell lines(NIH 3T3,C3 H clones),embryonic fibroblast cell lines and T-lymphoma cell lines(S1A.TB,TIMI.4 and R1.1)]; rat(T cells:Rat2,RGE,XC and HH16,and alveolar cells:NR8383) and primary guinea pigs derived AMs,in HIV-MTB studies is also described.Given the spectrum of the models available,cell cultures offer great potential for host-HIV-MTB interactions studies.

Are Drug Efflux Genes Present among <i>Mycobacterium tuberculosis</i>Isolates from Patients in Lagos, Nigeria?

A major challenge in the treatment of Tuberculosis (TB) is emergence of Multi-Drug Resistant Mycobacterium tuberculosis (MDRTB) strains. Efflux genes have been established to be among factors for drug resistance in Mycobacterium tuberculosis (M. tuberculosis) pulmonary infections by conferring bacterial ability to pump-out drugs from intracellular compartment, making it impossible for drugs to attain intracellular concentration lethal to the organism. There is paucity of data on the role of efflux pump in MDRTB in Nigerian strains of M. tuberculosis. Hence, the aim of this study was to detect the carriage, distribution and frequency of efflux pump genes among MDRTB and non-MDRTB isolates from participants with pulmonary tuberculosis in Lagos, Nigeria. This study was carried out on M. tuberculosis isolated from 1020 participants suspected of pulmonary tuberculosis in Lagos State, Nigeria. A total of 78 M. tuberculosis isolates were obtained from the participants suspected of pulmonary tuberculosis. Forty Eight isolates were confirmed as MDRTB and 30 non-MDRTB. Efflux pump genes were investigated in the isolates using the conventional polymerase chain reaction. Statistical analysis was carried out using the Statistical Package for Social Science (SPSS version 20) to compare the efflux pump gene results between MDRTB and non- MDRTB isolates. Different efflux genes types and frequency were detected in MDRTB and non-MDRTB isolates. Carriage of 2 or more alleles of efflux gene types Rv2486c (efpA), Rv2459c (jefA), Rv1877, Rv1002c, Rv0342, Rv2686c and drrC associated with MDR were detected. Additionally, the frequency of efflux genes alleles in MDRTB was significantly different from those in non- MDRTB isolates.

The Effectiveness of Infection Control Practices among Health Care Workers Responding to the COVID-19 Pandemic in Nigeria

Background: The world is currently experiencing a healthcare crisis caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). Healthcare workers (HCWs) are at the forefront of controlling the spread of the disease;this response has resulted in a huge number of infections amongst HCWs and unfortunately some casualties. Infection prevention and control practices (IPC) are practical, proven methods that prevent avoidable harm to patients and protect health workers from contagious infection. This study was done to evaluate the effectiveness of IPC practices utilized in COVID-19 testing drive through facility in Lagos Nigeria. Method: The facility recruited 42 HCWs who were trained on IPC and use of Personal Protective Equipment (PPEs). Training on donning and doffing of PPEs, preparation of decontaminants and sample handling were done for relevant personnel. A daily log for monitoring COVID-19 symptoms was deployed to all HCWs;to help early detection of COVID-19 infection and prevent transmission amongst staff. Results: Of 42 personnel, 92.8% had a tertiary level of education while 71.4% had at least 5 years work experience. A total of 5 (11.9%) out of 42 HCWs were positive by week six of the study. All infected persons worked at the drive through centre. Most common symptom filled in the daily log tool was headache and fatigue. Conclusion: Despite all the measures introduced, 11.9% of HCWs became positive within 6 weeks, showing the highly infectious nature of the virus and the need to research into more effective measures in preventing the transmission of highly infectious pathogens to HCWs during outbreaks.

Clinical Features of Spontaneous Remission in the Classic Fever of Unknown Origin:A Retrospective Study

Objective To summarize the clinical features of spontaneous remission in classic fever of unknown origin(FUO).Methods Medical records of 121 patients diagnosed with FUO at admission in Peking Union Medical College Hospital between January 2018 and June 2018 were reviewed retrospectively.Patients who were discharged without etiological diagnoses were followed for 2 years.The clinical features and outcomes of these patients were summarized.Multivariate logistic regression was used to analyze related factors of spontaneous remission of FUO.Results After excluding 2 patients who lost to follow-up,the etiology of 119 FUO patients were as follows:infectious diseases in 30(25.2%)cases,connective tissue diseases in 28(23.5%)cases,tumor diseases in 8(6.7%)cases,other diseases in 6(5.0%)cases,and unknown diagnoses in 47(39.5%)cases.Totally,41 patients experienced spontaneous remission of fever(the median time from onset to remission was 9 weeks,ranging from 4 to 39 weeks).In patients with spontaneous remission in FUO,lymphadenopathy was less common clinical manifestation,the levels of inflammatory markers including leukocyte count,neutrophil count,neutrophil ratio,C-reactive protein,and ferritin were lower,and the proportion of CD8 positive T lymphocytes expressing CD38 was lower.Multivariate logistic regression analysis of factors with a P-value<0.05 in univariate analysis shown that white blood cell count(OR:0.S45,95%CI:0.306-0.971,P=0.039),neutrophil count(OR:2.074,95%CI:1.004-4.284,P=0.049),and proportion of neutrophils(OR:0.928,95%Cl:0.871-0.990,P=0.022)were independent significant factors associated with spontaneous remission in FUO.Conclusions This study suggested that most patients discharged with undiagnosed classic FUO would remit spontaneously.Thus,for patients with stable clinical conditions,follow-up and observation could be the best choice.Patients with lower level of some inflammatory factors may have a high likelihood of spontaneous remission in classic FUO.