Occurrence of Extended-spectrum ß-lactamase (ESBL) and Carbapenemase-producing Escherichia coli isolated from Childhood Diarrhoea in Yaoundé, Cameroon.

INTRODUCTION: Extended-spectrum ß-lactamase (ESBL)-producing pathogenic E. coli is a global public health issue, especially in sub-Saharan African countries such as Cameroon. It contributes to increase significantly hospital length of stay, morbidity, mortality and economic costs because of treatment failures. This study aims at determining the resistance background and virulence profiles of ESBL-E. coli isolates among childhood diarrhoea during the cholera outbreak occuring in Yaoundé, Cameroon. MATERIALS AND METHODS: During a four-month periods, from March 1st to June 30th, 2023,  a total of 84 stool samples were collected from 90 under five children presenting clinical signs of gastroenteritis and attending four hospitals in Yaoundé, Cameroon. Bacterial identification was done using API20E and antimicrobial susceptibility test was performed using the Kirby-Bauer disc diffusion method. After extraction, genomic DNA was subjected to conventional and multiplex polymerase chain reaction methods (PCRs) for detection of resistance and virulence genes. Statistical analysis was performed using Epi info™ (7.2.5.0). Statistical significance was considered at a p-value < 0.05. RESULTS: Out of 150 patients contacted, 90 patients were enrolled, 84 samples were collected, 52.38%(44/84) and 3.57%(03/84) were confirmed as extended-spectrum ß-lactamase and carbapenemase-producing E. coli respectively. The risk factors were analyzed, and children who drank natural fruit juice (OR: 0.4, p-value: 0.03) were found to be significantly associated with ESBL-producing E. coli. The ESBL-producing E. coli isolates showed a high level of resistance to amoxicillin-clavulanic acid, cefotaxime, ceftazidime, cefepime, colistin, and tetracycline. The blaCTX-M was more prevalent ß-lactamase resistance gene. The tetracycline resistance genes tet(A) and tet(B) were also detected. The most important virulence genes detected were FimH (81.81%) and papA (79.54%). CONCLUSION: These findings suggest implementing routine surveillance and screening for antimicrobial resistance among children under five. Antimicrobial stewardship strategies (ASP) need to be implemented to curb the emergence and dissemination of ESBL-producing E. coli. In addition, a national surveillance program for antimicrobial resistance needs to be implemented at local and regional levels in order to reduce morbidity in Cameroon.

Specific antibody responses to Qß-displayed Plasmodium falciparum-derived UB05 and MSP3 proteins in mother-neonate couples.

Malaria blood-stage parasite is a critical pathogenic stage responsible for serious adverse outcomes in pregnant women and their neonates. Immunoglobulin G (IgG) antibody responses specific to various asexual blood-stage antigens were well reported in non-pregnant individuals. However, little is still known during placental malaria. To assess the antibody responses specific to Plasmodium falciparum-derived MSP3 and UB05 malaria vaccine candidates in mother-neonate couples, mother's peripheral blood and neonate's cord blood samples were collected at delivery. After malaria diagnostic, plasma levels of IgG and IgG subclass responses specific to UB05, MSP3 and UB05-MSP3 were determined using ELISA. As outcomes, both mothers and neonates had significantly higher IgG responses to UB05 and UB05-MSP3 compared to anti-MSP3 IgG (p < 0.05), irrespective of malaria status. Significant negative correlations were observed between IgG levels specific to the three antigens and parasitaemia (p < 0.01). Anti-UB05 and anti-UB05-MSP3 IgG levels in neonates showed a significant positive correlation with the corresponding mothers' antibodies (rs = 0.25 with p = 0.04; rs = 0.31 with p = 0.01, respectively). UB05MSP3-specific IgG3 and IgG1 subclass responses were significantly higher than the IgG4 subclass (p < 0.01). The neonates IgG1 and IgG3 levels positively correlated with the corresponding antibody subclasses of mothers. These findings suggest an association between UB05 and UB05-MSP3-specific antibody responses and malaria control during pregnancy. Maternal-foetal transfer of MSP3 and UB05-specific IgG occurs during pregnancy, suggesting the interest in the future malaria vaccination strategies in pregnant women to generate early protective immunity in baby against malaria.

Diabetes Mellitus and HIV Infection among Newly Diagnosed Pulmonary Tuberculosis Patients in the North West Region of Cameroon: A Cross-Sectional Study.

Objective: To determine the prevalence rate of HIV and diabetes among tuberculosis (TB) patients and also the comorbidity rate. Design: Cross-sectional study. Setting. This study was carried out at the Tuberculosis Reference Laboratory, Regional Hospital Bamenda, North West Region of Cameroon, from January 2017 to December 2019. Participants. 1115 cases of pulmonary tuberculosis aged ≥14 years (mean 42.5 ± 15.28 years). Methods: Sputum samples collected were acid-fast stained and examined macroscopically as well as inoculated for culture. A chest X-ray was performed for further confirmation of TB diagnosis. After the TB diagnosis was done, fasting blood glucose, 2 h-PG test, HbA1c, and biochemical enzymatic tests were performed for the diagnosis of diabetes. Rapid strip test and enzyme-linked immunosorbent assay were used to diagnose HIV infection. Interventions. No intervention was done during the period of study. Outcome Measures. The prevalence of TB/HIV and TB/HIV/DM, signs and symptoms, imaging results, and bacteriology status among TB/HIV, TB/HIV/DM coinfected, and comorbidity cases. Results: Of 1115 participants, 38.57% had TB/HIV, and 5.83% had TB/HIV/DM. Among TB/HIV/DM cases, 20.39% had a cough for more than 2 weeks [p < 0.0001; OR (95%CI): 4.866 (3.170-7.404)], and 35.71% had a fever for at least 2 weeks [p < 0.0001; OR (95%CI): 7.824 (5.336-11.36)]. The majority of TB/HIV/DM patients (77.42%) had chest pain for at least 2 weeks [p < 0.0001; OR (95%CI): 114.3 (59.78-207.1)]. 7.41%, 14.18%, and 9.09% of TB/HIV/DM, respectively, had chest abnormality, positive smear, and positive culture (p = 0.018). Significant differences were observed between signs and symptoms, imaging results, bacteriology, treatment history for TB cases and those with HIV and/or DM, and those without HIV and/or DM coinfection and comorbidity. Conclusion: This study reports a high prevalence of DM comorbidity and HIV coinfection among active TB patients in the North West Region of Cameroon as well as TB/HIV/DM comorbidity.

Group B Streptococcus colonisation, prevalence, associated risk factors and antimicrobial susceptibility pattern among pregnant women attending antenatal care at Dschang District Hospital, West Region of Cameroon: A hospital-based cross-sectional study.

BACKGROUND: Group B Streptococcus (GBS), also known as Streptococcus agalactiae, is a Gram-positive bacterium known for its ability to colonise the vaginal and rectal areas of the mother and is a leading cause of neonatal mortality and morbidity. This study aimed at determining the prevalence, associated risk factors and antimicrobial susceptibility of GBS colonisation among pregnant women attending antenatal care (ANC) at Dschang District Hospital. METHODS: This hospital-based cross-sectional study used a multistage sampling method to recruit a total of 621 consented pregnant women who attended ANC in Dchang District Hospital. The 621 Participants at 23.5 ± 6.4 weeks gestation each completed a questionnaire and vaginal swabs were collected for GBS analysis. RESULTS: Among the 621 pregnant women that were included in this study, the colonisation rate of GBS was found to be 8.69%. Induced abortion (odds ratio [CI] = 3.09, 95% [1.56-6.21]), Spontaneous abortions (OR = 2.82, 95% CI 1.14-7.29), Stillbirth (OR [CI] = 7.75, 95% [2.61-21.71]), Fever (OR [CI] = 0.37, 95% [0.19-0.71]) and anaemia (OR [CI] = 0.22, 95% [0.12-0.43]) were found to be factors associated with GBS colonisation. CONCLUSION: Our findings suggest that we found that, induce abortion, spontaneous abortions and stillbirths were highly associated rates of GBS colonisation, while fever and anaemia were associated with lower rates of GBS colonisation. Further longitudinal research is needed to establish the causal relationship and its biological mechanisms.

A cross-sectional study of acute dengue infection in paediatric clinics in Cameroon.

BACKGROUND: Dengue fever is the world's fastest spreading mosquito borne viral infection. It is prevalent throughout both subtropical and tropical region, and affects over 128 countries. Dengue virus (DENV) infection poses a serious global public health challenge to three billion people, resulting in approximately 200 million cases of morbidity and 50,000 cases of mortality annually. In Cameroon like in most sub-Saharan African countries, DENV infection occur concurrently with other infectious diseases whose symptoms often overlap, rendering differential diagnosis challenging. This study aims at determining the frequency of acute dengue among febrile children under 15 years attending hospitals in some areas of Cameroon. METHODS: A total of 961 children under the age of 15 were recruited in a cross-sectional study using systematic sampling technique and by selecting each subject out of the three. The study was conducted in 10 public health centers in Cameroon. Demographic data and risk factors of the subjects were obtained using well-structured questionnaires. Dengue virus NS1 antigen, IgM and IgG were analysed using a Tell me fast® Combo Dengue NS1-IgG/IgM Rapid Test. An in-house ELISA test for dengue specific IgM antibody was equally performed for confirmation. Descriptive statistical analysis was performed using Graph pad version 6.0. RESULTS: A prevalence of 6.14% acute dengue virus infection was observed among children with febrile illness with a significant difference (p = 0.0488) between males (4.7%) and females (7.7%). In addition, children who reportedly were unprotected from vectors, showed a comparatively higher prevalence of the disease seropositivity than those practicing protective measures. CONCLUSION: DENV infection therefore is an important cause of fever among children in Cameroon. Thus, there is a need to include differential screening for DENV infections as a tool in the management of fever in children in the country.

Filaria specific antibody response profiling in plasma from anti-retroviral naïve Loa loa microfilaraemic HIV-1 infected people.

BACKGROUND: In West and Central Africa areas of endemic Loa loa infections overlap with regions of high prevalence of human immunodeficiency virus type 1 (HIV-1) infections. Because individuals in this region are exposed to filarial parasites from birth, most HIV-1 infected individuals invariably also have a history of filarial parasite infection. Since HIV-1 infection both depletes immune system and maintains it in perpetual inflammation, this can hamper Loa loa filarial parasite mediated immune modulation, leading to enhanced loaisis. METHODS: In this study we have assessed in plasma from asymptomatic anti-retroviral (ARV) naïve Loa loa microfilaraemic HIV-1 infected people the filarial antibody responses specific to a filariasis composite antigen consisting of Wbgp29-BmR1-BmM14-WbSXP. The antibody responses specific to the filariasis composite antigen was determined by enzyme linked immunosorbent assay (ELISA) in plasma from ARV naïve Loa loa microfilaraemic HIV-1 infected participants. In addition the filarial antigen specific IgG antibody subclass profiles were also determined for both HIV-1 positive and negative people. RESULTS: Both Loa loa microfilaraemic HIV-1 positive and negative individuals showed significantly higher plasma levels of IgG1 (P < 0.0001), IgG2 (P < 0.0001) and IgM (P < 0.0001) relative to amicrofilaraemic participants. A significant increase in IgE (P < 0.0001) was observed exclusively in Loa loa microfilaraemic HIV-1 infected people. In contrast there was a significant reduction in the level of IgG4 (p < 0.0001) and IgG3 (P < 0.0001) in Loa loa microfilaraemic HIV-1 infected individuals. CONCLUSIONS: Loa loa microfilaraemia in ARV naïve HIV-1 infected people through differential reduction of plasma levels of filarial antigen specific IgG3, IgG4 and a significant increase in plasma levels of filarial antigen specific IgE could diminish Loa loa mediated immune-regulation. This in effect can result to increase loaisis mediated immunopathology in antiretroviral naive HIV-1 infected people.

Treatment of Helicobacter pylori infected mice with Bryophyllum pinnatum, a medicinal plant with antioxidant and antimicrobial properties, reduces bacterial load.

CONTEXT: Bryophyllum pinnatum (Lam.) Kurz (Crassulaceae) is a plant known for its antiulcer properties. OBJECTIVE: This study evaluates the anti-Helicobacter pylori activity of Bryophyllum pinnutum methanol extract with a mouse model and its antioxidant properties. MATERIALS AND METHODS: Dried leaves of Bryophyllum pinnutum were extracted with methanol and ethyl acetate. Broth microdilution method was used to evaluate the anti-Helicobacter activity of extract samples in vitro. Swiss mice were inoculated with a suspension of Helicobacter pylori and divided into control group and four others that received 125, 250, 500 mg/kg of methanol extract or ciprofloxacin (500 mg/kg), respectively, for 7 days. Helicobacter pylori colonization and bacterial load of mouse stomach was assessed on day 1 and 7 post-treatment. The antioxidant activity of Bryophyllum pinnutum was evaluated through DPPH radical, hydroxyl radical and reducing power assay. RESULTS: Methanol extract showed a significant anti-Helicobacter activity with MIC and MBC values of 32 and 256 µg/mL, respectively. Bryophyllum pinnatum and ciprofloxacin reduced H. pylori colonization of gastric tissue from 100% to 17%. Bryophyllum pinnatum extract (85.91 ± 52.91 CFU) and standard (25.74 ± 16.15 CFU) also reduced significantly (p < 0.05) bacterial load of gastric mucosa as compared to untreated infected mice (11883 ± 1831 CFU). DPPH radical, hydroxyl radical and reducing power assays showed IC50 values of 25.31 ± 0.34, 55.94 ± 0.68 and 11.18 ± 0.74 µg/mL, respectively. DISCUSSION AND CONCLUSION: The data suggest that the methanol extract of Bryophyllum pinnatum could inhibit Helicobacter pylori growth, and may also acts as an antioxidant to protect gastric mucosa against reactive oxygen species.

Dengue virus serological markers among potential blood donors: an evidence of asymptomatic dengue virus transmission in Cameroon.

INTRODUCTION: the risk of dengue virus or its antibodies which can be transmitted through blood transfusion by asymptomatic individuals infected, has been a major concern all over the world. Dengue is an endemic disease in sub-Saharan Africa, particularly in Cameroon. The purpose of this study is to determine the frequency of dengue virus (DENV) infection among potential blood donors at Yaounde Jamot Hospital. METHODS: serum samples were collected from 310 potential adult blood donors aged 18-57 years, who signed a written informed consent and completed the questionnaire between March 2019 and August 2019. This serum is used to screen for the presence of serological markers of DENV infection (NS1, IgM and IgG) using immunochromatographic tests (Zhuhai Encode Medical Engineering Co., Ltd, China). IgM/IgG positive samples were confirmed by enzyme-linked immunosorbent assays (ELISA). RESULTS: the overall prevalence was 24.8% among potential blood donors were subdivided as follows: 4.5% (14/310), 12.3% (38/310) and 6.1% (19/310) showed mono-positivity to DENV-NS1 antigen, anti-DENV IgM and anti-DENV IgG antibodies respectively. 1.9% (6/310) of potential blood donors showed dual positivity to anti-DENV IgM antibodies and anti-DENV IgG antibodies. The presence of DENV-NS1 antigen show asymptomatic viremia of dengue at the time of donation, while the presence of IgG antibodies reflects the high endemicity of dengue disease in the city of Yaoundé. CONCLUSION: these findings demonstrate the high level of risk of the DENV transmission among potential blood donors to needy recipients, underscoring the importance of establishing dengue fever blood screening in different services and blood collection units in Cameroon to improve safety transfusion and control the dissemination of the DENV.

In vivo targeting of protein antigens to dendritic cells using anti-DEC-205 single chain antibody improves HIV Gag specific CD4+ T cell responses protecting from airway challenge with recombinant vaccinia-gag virus.

INTRODUCTION: Targeting antigens to dendritic cells (DCs) in vivo via a DC-restricted endocytic receptor, DEC205, has been validated to enhance immunity in several vaccine platforms. Particularly atttractive is selected delivery of proteins to DCs in vivo because it enables proteins to be more immunogenic and provides a cheaper and effective way for repeated immunizations. METHODS: In this study, we tested the efficacy of a single chain antibody to DEC205 (scDEC) to deliver protein antigens selectively to DCs in vivo and to induce protective immunity. RESULTS: In comparison to soluble Ovalbumin (OVA) antigen, when recombinant scDEC:OVA protein was injected subcutaneously (s.c.) into mice, the OVA protein was selectively presented by DCs to both TCR transgenic CD8+ and CD4+ T cells approximately 500 and 100 times more efficient than soluble OVA, respectively, and could persist for seven days following s.c. injection of the scDEC205:OVA. Similarly selective targeting of HIV Gag P24 to DCs in vivo using scDEC-Gag protein plus polyICLC vaccine resulted in strong, long lasting, polyfuntional CD4+ T cells in mice which were protective against airway challenge by a recombinant vaccinia-gag virus. CONCLUSION: Thus targeting protein antigens to DCs using scDEC can be used either alone or in combination with other strategies for effective immunization.

Seroprevalence of dengue virus among children presenting with febrile illness in some public health facilities in Cameroon.

INTRODUCTION: A routine diagnosis of Dengue virus (DENV) infection is not usually conducted in hospitals. Because symptoms overlap, many potential febrile illnesses due to DENV may be confused for malaria, typhoid or paratyphoid (enteric) fever. The absence of data on DENV exposure rates among children attending health facilities could undermine management of this disease. This study aimed to investigate the seroprevalence of dengue virus infection in children presenting febrile illness in some public health facilities in Cameroon. METHODS: A cross-sectional study was performed in children ≤ 15 years attending seven urban and three semi-urban public hospitals of Cameroon. From each volunteer, 2ml of whole blood was collected and tested for dengue virus IgM, malaria (Pf/Pan antigens) and enteric fever (Typhoid IgM) using rapid diagnostic tests (RDT); in order to allow the healthcare workers to quickly put the positive cases under appropriate treatment. Positive cases of dengue virus infection were confirmed by indirect ELISA. Data analysis were performed using the statistical package for social sciences software, version 22.1. RESULTS: A total of 961 children were enrolled in the study and 492 (51.2%) were infected with at least one of the three pathogens. Overall, DENV IgM seroprevalence among febrile children was 14.4% (138/961). About 390 (40.6%) and 22 (2.3%) had malaria (Pf/Pan Ag) and enteric fever (Typhoid IgM) respectively. Co-infection with dengue virus was found in 51 (5.3%) participants. The dengue virus IgM seroprevalence was higher in Bankim (19.3%), Ntui (18.3%) and Douala (18.2%). CONCLUSION: Dengue virus infection seroprevalence appears to be low in children presenting with febrile illness in the studied health centres in Cameroon but call for more attention and research to further characterise the circulating strains of the dengue virus.

The Effect of Antiretroviral Naïve HIV-1 Infection on the Ability of Natural Killer Cells to Produce IFN-γ upon Exposure to Plasmodium falciparum-Infected Erythrocytes.

BACKGROUND: In sub-Saharan Africa, intense perennial Plasmodium species transmission coincides with areas of high prevalence of the human immunodeficiency virus type 1 (HIV) infection. This implies that antiretroviral naïve HIV-infected people living within these regions are repeatedly exposed to Plasmodium species infection and consequently malaria. Natural killer (NK) cells are known to contribute to malaria immunity through the production of IFN-γ after exposure to Plasmodium falciparum-infected erythrocytes (infected red blood cells [iRBC]). However, in antiretroviral naïve HIV-1 infection, these functions could be impaired. In this study we assess the ability of NK cells from antiretroviral naïve HIV-1-infected people to respond to iRBC. METHOD: Magnetically sorted NK cells from antiretroviral naïve HIV-1-infected people were tested for their ability to respond to iRBC following in vitro coculture. NK cell IFN-γ production after coculture was measured through multiparametric flow cytometry analysis. RESULTS: Our data show a significant reduction (p = 0.03) in IFN-γ production by NK cells from antiretroviral naïve HIV-1-infected people after coculture with iRBCs. This was in contrast to the NK cell response from healthy controls, which demonstrated elevated IFN-γ production. NK cell IFN-γ production from untreated HIV-1-infected participants correlated inversely with the viral load (r = -0.5, p = 0.02) and positively with total helper CD4+ T-cell count (r = 0.4, p = 0.04). Thus, antiretroviral naïve HIV-1 infection can dampen NK cell-mediated immunity to P. falciparum infection in malaria-intense regions. This could in effect escalate morbidity and mortality in people chronically infected with HIV-1.