Immunopathology in human pulmonary tuberculosis: Inflammatory changes in the plasma milieu and impaired host immune cell functions.

Host immune response is key for protection in tuberculosis, but the causative agent, Mycobacterium (M.) tuberculosis, manages to survive despite immune surveillance. Key mechanisms of immune protection have been identified, but the role of immunopathology in the peripheral blood of tuberculosis patients remains unclear. Tuberculosis immunopathology in the blood is characterised by patterns of immunosuppression and hyperinflammation. These seemingly contradictory findings and the pronounced heterogeneity made it difficult to interpret the results from previous studies and to derive implications of immunopathology. However, novel approaches based on comprehensive data analyses and revitalisation of an ancient plasma milieu in vitro assay connected inflammation with immunosuppressive factors in tuberculosis. Moreover, interrelations between the aberrant plasma milieu and immune cell pathology were observed. This review provides an overview of studies on changes in plasma milieu and discusses recent findings linking plasma factors to T-cell and monocyte/macrophage pathology in pulmonary tuberculosis patients.

Monocyte pathology in human tuberculosis is due to plasma milieu changes and aberrant STAT signalling.

Monocyte-derived macrophages contribute centrally to immune protection in Mycobacterium tuberculosis infection and changes in monocyte phenotype characterize immunopathology in tuberculosis patients. Recent studies highlighted an important role of the plasma milieu in tuberculosis immunopathology. Here, we investigated monocyte pathology in patients with acute tuberculosis and determined tuberculosis plasma milieu effects on phenotype as well as cytokine signalling of reference monocytes. Patients with tuberculosis (n = 37) and asymptomatic contacts (controls n = 35) were recruited as part of a hospital-based study in the Ashanti region of Ghana. Multiplex flow cytometry phenotyping of monocyte immunopathology was performed and effects of individual blood plasma samples on reference monocytes prior to and during treatment were characterized. Concomitantly, cell signalling pathways were analysed to elucidate underlying mechanisms of plasma effects on monocytes. Multiplex flow cytometry visualization characterized changes in monocyte subpopulations and detected higher expression of CD40, CD64 and PD-L1 in monocytes from tuberculosis patients as compared to controls. Aberrant expression normalized during anti-mycobacterial treatment and also CD33 expression decreased markedly. Notably, higher CD33, CD40 and CD64 expression was induced in reference monocytes when cultured in the presence of plasma samples from tuberculosis patients as compared to controls. STAT signalling pathways were affected by the aberrant plasma milieu and higher levels of STAT3 and STAT5 phosphorylation was found in tuberculosis plasma-treated reference monocytes. Importantly, high pSTAT3 levels were associated with high CD33 expression and pSTAT5 correlated with CD40 as well as CD64 expression. These results suggested plasma milieu effects with potential implications on monocyte phenotype and function in acute tuberculosis.

Cytokine-induced transient monocyte IL-7Ra expression and the serum milieu in tuberculosis.

Bacterial components and cytokines induce IL-7 receptor (IL-7Rα) expression in monocytes. Aberrant low IL-7Rα expression of monocytes has been identified as a feature of tuberculosis immunopathology. Here, we investigated the mechanisms underlying IL-7Rα regulation of monocytes and tuberculosis serum effects on IL-7Rα expression. Serum samples from tuberculosis patients and healthy controls, cytokine candidates, and mycobacterial components were analyzed for in vitro effects on IL-7Rα expression of primary monocytes, monocyte-derived macrophages (MDM), and monocyte cell lines. IL-7Rα regulation during culture and the role of FoxO1 were characterized. In vitro activation-induced IL-7Rα expression in human monocytes and serum samples from tuberculosis patients boosted IL-7Rα expression. Although pathognomonic tuberculosis cytokines were not associated with serum effects, we identified cytokines (i.e., GM-CSF, IL-1ß, TNF-α, IFN-γ) that induced IL-7Rα expression in monocytes and/or MDM comparable to mycobacterial components. Blocking of cytokine subsets (i.e., IL-1ß/TNF-α in monocytes, GM-CSF in MDM) largely diminished IL-7Rα expression induced by mycobacterial components. Finally, we showed that in vitro-induced IL-7Rα expression was transient and dependent on constitutive FoxO1 expression in primary monocytes and monocyte cell lines. This study demonstrated the crucial roles of cytokines and constitutive FoxO1 expression for transient IL-7Rα expression in monocytes.

Lower IL-7 Receptor Expression of Monocytes Impairs Antimycobacterial Effector Functions in Patients with Tuberculosis.

Altered monocyte differentiation and effector functions characterize immune pathogenesis of tuberculosis. IL-7 is an important factor for proliferation of T cells and impaired IL-7 sensitivity due to decreased IL-7 receptor α-chain (IL-7Rα) expression was found in patients with acute tuberculosis. Peripheral blood monocytes have moderate IL-7Rα expression and increased IL-7Rα levels were described for inflammatory diseases. In this study, we investigated a potential role of IL-7 and IL-7Rα expression for monocyte functions in tuberculosis. We analyzed the phenotype of monocytes in the blood from tuberculosis patients (n = 33), asymptomatic contacts of tuberculosis patients (contacts; n = 30), and healthy controls (n = 20) from Ghana by multicolor flow cytometry. Mycobacterial components were analyzed for their capacity to induce IL-7Rα expression in monocytes. Functional effects of monocyte to IL-7 were measured during signaling and by using an antimycobacterial in vitro kill assay. Monocytes were more frequent in peripheral blood from patients with tuberculosis and especially higher proportions of CD14+/CD16+ (M1/2) monocytes with increased PD-L1 expression characterized acute tuberculosis. IL-7Rα expression was decreased particularly on M1/2 monocytes from patients with tuberculosis and aberrant low expression IL-7Rα correlated with high PD-L1 levels. Constitutive low pSTAT5 levels of monocytes ex vivo and impaired IL-7 response confirmed functionally decreased monocyte IL-7 sensitivity of patients with tuberculosis. Mycobacteria and mycobacterial cell wall components induced IL-7 receptor expression in monocytes and IL-7 boosted mycobacterial killing by monocyte-derived macrophages in vitro. We demonstrated impaired monocyte IL-7 receptor expression as well as IL-7 sensitivity in tuberculosis with potential effects on antimycobacterial effector functions.

Knowledge and attitudes towards antibiotic use and resistance among undergraduate healthcare students at University of Rwanda.

BACKGROUND: Antimicrobial resistance (AMR) is an imminent threat to modern medicine. As the efficacy of treatment regimens is reduced, mortality and morbidity attributed to infectious diseases is expected to rise dramatically across the globe. Antimicrobial stewardship and good prescription practices are critical to conserving available therapeutics; it is appropriate, therefore, to appraise our attitudes and knowledge of antimicrobial resistance, particularly for the future healthcare practitioners. METHODS: This is a descriptive cross-sectional study that was conducted among 282 medicals, dental and pharmacy students from the University of Rwanda. Questionnaires were used to collect data from the 4th to 29th March 2017. RESULTS: Students from Level 3 to level 6 have demonstrated a good knowledge on antibiotics and antimicrobial resistance. Generally, 95% (n = 218) agreed that the inappropriate use of antibiotics could lead to antibiotic resistance. It was found that 96% (n = 220) of the respondents had heard about AMR outside their degree courses. 49% (n = 112) of the participants reported that they are able to purchase antibiotics without a prescription. 96% (n = 220) agreed that it was important for healthcare students to be knowledgeable about antimicrobial resistance. Perhaps most surprisingly, it was found that 83% (n = 191) of participants were unfamiliar with the concept of antimicrobial stewardship and 49% (n = 21) had not yet discussed antimicrobial resistance as part of their education, albeit only 1% (n = 3) was completely unfamiliar with the term. Furthermore, 38% (n = 86) did not support that the antibiotics were overused in Rwanda, 23% (n = 10) did not agree that inappropriate antimicrobial use contributed to antimicrobial resistance, and 50% (n = 22) of participants agreed that antibiotics were indicated in the treatment of pain and inflammation. CONCLUSIONS: The present study reports a moderate knowledge on AMR among the healthcare students. The gaps in the current formal training of healthcare individuals have been identified as well. We highlight the necessity to enhance educational approaches to introduce the key concepts of AMR and antimicrobial stewardship to the curriculum of healthcare students.

Highly successful treatment outcome of multidrug-resistant and genetic diversity of multidrug-resistant Mycobacterium tuberculosis strains in Rwanda.

OBJECTIVE: To determine prevalent MDR-TB genotypes and describe treatment outcome and bacteriology conversion in MDR-TB patients. METHODS: Review of laboratory records of 173 MDR-TB patients from all over Rwanda who initiated treatment under programmatic management of MDR-TB (PMDT) between 2014 and 2015. Fifty available archived isolates were genotyped by mycobacterial interspersed repetitive units - variable number of tandem repeats (MIRU-VNTR) genotyping. RESULT: Of the 170 patients whose outcome was known, 114 (66.3%) were cured and 36 (21%) completed the treatment, giving a successful outcome (cured and completed) of 150 (87.3%) patients. Of 20 MDR-TB patients with unfavourable treatment outcome, 18 died, one failed and one defaulted/stopped treatment. Of the 18 patients who died, 11 (61%) were HIV-coinfected. The treatment outcome was successful for 93.9% among HIV negative and 81.8% among HIV-coinfected patients (P = 0.02). Sputum smear conversion occurred in 3, 46, 57 and 78 patients before 2, 3, 4 and 6 months, respectively, with median time of sputum smear and culture conversion at 3 months. The 44 MDR-TB isolates with MIRU-VNTR result, showed high genetic diversity with low clustering rate (9.09%) and Uganda II being the most prevalent sub-family lineage detected in 68.2% of isolates. Beijing family was the least common genotype detected (2.3%, 1 isolate). CONCLUSION: The high success rates for MDR-TB treatment achieved in Rwanda were comparable to outcomes observed in resource-rich settings with HIV being an independent risk factor for poor treatment outcome. High genetic diversity and low clustering rate reported here suggest that reactivation of previous disease plays an important role in the transmission of MDR-TB in Rwanda.

OBJECTIF: Déterminer les génotypes prévalents de la TB-MDR et décrire les résultats du traitement et la conversion bactériologique chez les patients atteints de TB-MDR. MÉTHODES: Analyse des dossiers de laboratoire de 173 patients atteints de TB-MDR de l'ensemble du Rwanda qui ont débuté un traitement sous prise en charge programmatique de la TB-MDR (PMDT) entre 2014 et 2015. Cinquante isolats archivés disponibles ont été génotypés pour les unités répétitives intercalées de mycobactéries - nombre variable de tandems répétés (MIRU-VNTR). RÉSULTAT: Sur les 170 patients dont l'issue était connue, 114 (66,3%) étaient guéris et 36 (21%) avaient terminé le traitement, ce qui donne un résultat positif (guéri et complété) de 150 patients (87,3%). Sur 20 patients atteints de TB-MDR dont l'issue du traitement était défavorable, 18 sont décédés, un a eu un échec et le dernier a abandonné/arrêté le traitement. Sur les 18 patients décédés, 11 (61%) étaient coinfectés par le VIH. Le résultat du traitement a été positif pour 93,9% des personnes VIH négatives et 81,8% pour ceux coinfectées par le VIH (p = 0,02). La conversion des frottis d'expectoration est survenue chez 3, 46, 57 et 78 patients respectivement à 2, 3, 4 et 6 mois, avec une durée médiane entre le frottis d'expectoration et la conversion de culture de 3 mois. Les 44 isolats de TB-MDR avec un résultat MIRU-VNTR ont montré une diversité génétique élevée avec un faible taux de regroupement (9,09%) et la sous-famille de la lignée Ouganda II étant la plus prévalente détectée dans 68,2% des isolats. La famille Beijing était le génotype le moins fréquemment détecté (2,3%, 1 isolat). CONCLUSION: Les taux de succès élevés du traitement de la TB-MDR obtenus au Rwanda étaient comparables aux résultats observés dans les régions riches en ressources, le VIH étant un facteur de risque indépendant d'un mauvais résultat du traitement. La diversité génétique élevée et le faible taux de regroupement rapportés ici suggèrent que la réactivation d'une maladie antérieure joue un rôle important dans la transmission de la TB-MDR au Rwanda.

Incidence, root causes, and outcomes of surgical site infections in a tertiary care hospital in Rwanda: a prospective observational cohort study.

BACKGROUND: Surgical Site Infections (SSI) are the most reported health acquired infection and common surgical complication in both developed and developing countries. In developing countries such as Rwanda, there is a paucity of published reports on the pattern of SSI, therefore this study aimed at assessing the incidence, risk factors and the antibiotic profile of pathogens responsible of SSI. METHODS: This prospective study included 294 patients admitted between October 10, 2017 and February 12, 2018 to the surgical department of the University Teaching Hospital of Kigali. Patients data were collected using a structured and pretested questionnaire in English version. Regular follow-up was maintained until at least 30 days postoperatively. Samples were collected from suspected wounds and identified using different bacteria culture media. Data were analyzed using Statistical Package for the Social Sciences (SPSS) software word version 20.0. P-value < 0.05 was considered statistically significant. RESULTS: The overall incidence of SSI was 10.9%. The associated risk factors were found to be an increased age, ASA class, wound classification, skills and experience of the surgeon, longer duration of surgery (> 2 h), prolonged duration of hospital stay, blood transfusion and emergency surgery. The most common pathogens isolated were Klebsiella ssp (55%), followed by Escherichia coli (15%) and Proteus ssp (12%), Acinectobacter (9%), Staphylococcus aureus (6%) and coagulase-negative staphylococci (3%).The pathogens revealed different levels of antibiotic resistance; amoxy-clavilinic acid (98.8%), gentamicin (92.6%), ciprofloxacin (78.1%) and ceftriaxone (53.3%). On the other hand, Amikacin and imipinem were the only two most effective antibiotics for all isolated pathogens with 100% sensitivity. CONCLUSION: SSI incidence rate was revealed to be within acceptable international ranges. However, multi drug resistance was seen in half of the isolates leaving clinicians with few choices of drugs for the treatment of patients with SSI. Periodic surveillance of bacteria and antibiotic susceptibility coupled with the implementation of strict protocol for antibiotic administration and operative room regulations are important to minimize the burden of SSI with resistant bacteria pathogens.

Hepatitis B vaccination coverage among healthcare workers at a tertiary hospital in Rwanda.

OBJECTIVE: We evaluated post-vaccination immunity status and describe potential risk factors associated with the lack of response among healthcare workers (HCWs) at a tertiary care hospital in Kigali, Rwanda. RESULTS: Of 373 HCWs, 291 (78.2%) were female and 81 (21.8%) were male. The mean age of the study participants was 40.2 years (standard deviation [SD], 7.7 years), within a range of 24-41 years. Participants' mean BMI was 25.4 ± 6.6 kg/m2, with more than half of patients (60.3%) being overweight. 96% received all three doses of vaccination. A total of 36 participants (9.6%) were considered non responders as they did not develop a sufficient anti-HBs response post vaccination. The anti-HBs response was significantly higher in females when compared to males (p = 0.02). Interestingly, there was no significant association between decline in antibody levels with age (p = 0.242) and BMI (p = 0.516) of the participants. The anti-HBs titers were similar in the group of participants who had received two doses and those who had received three doses of the HBV vaccination. Overall the findings of our study provide a basis for testing for anti-HBs in all HCWs post vaccination in Rwanda.