Phenotypic Characterization of Salmonella Typhimurium Isolates from Food-animals and Abattoir Drains in Buea, Cameroon

Salmonella spp. have been extensively incriminated worldwide as common causes of bacterial gastroenteritis in humans, with food-animals serving as important reservoirs. The study was aimed at investigating cattle and pigs slaughtered in Buea as reservoirs of Salmonella Typhimurium and the susceptibility of isolates to antibiotics. In total, 230 specimens (comprising 50 each from the rectum, ileum, and gall bladder of cattle; and 10 each from same anatomical sites of pigs and 50 from abattoir drains) were analyzed for Salmonella using the standard microbiological, biochemical and serological techniques. Antibiotic susceptibility of the isolates was determined by the Kirby-Bauer disc-diffusion test. The isolates were characterized into biotypes using the API 20E kit, and results were analyzed using the chi-square test. Seventy-five (32.6%) of the 230 specimens were positive for S. Typhimurium, with pigs and abattoir drains presenting the highest level of isolation (40%). Biochemical typing grouped the isolates into five biotypes. Biotype I was the most prevalent (30.6%) while biotype IV was the least prevalent (9.3%) and was absent in samples from pigs. Antibio-tic susceptibility studies revealed 14 antibiotypes based on antibiotics used in the study. The predominant antibiotype AMXR DOXRCEFR was recorded in 13 (17.3%) of the isolates. Multidrug resistance (to four or more antibiotics) was recorded in 50.7% (38/75) of the isolates. The most active drugs were ciprofloxacin (98.6%), ofloxacin (93.3%), amikacin (90.6%), and gentamicin (84%). All the isolates (100%) were resistant to tetracycline and ampicillin. Cattle and pigs were found to be reservoirs of S. Typhimurium in the environment of Buea, Cameroon, implying that foods from these sources, if not properly handled, could serve as vehicles for its transmission to humans

Phenotypic Characterization of Salmonella Typhimurium Isolates from Food-animals and Abattoir Drains in Buea, Cameroon

Salmonella spp. have been extensively incriminated worldwide as common causes of bacterial gastroenteritis in humans, with food-animals serving as important reservoirs. The study was aimed at investigating cattle and pigs slaughtered in Buea as reservoirs of Salmonella Typhimurium and the susceptibility of isolates to antibiotics. In total, 230 specimens (comprising 50 each from the rectum, ileum, and gall bladder of cattle; and 10 each from same anatomical sites of pigs and 50 from abattoir drains) were analyzed for Salmonella using the standard microbiological, biochemical and serological techniques. Antibiotic susceptibility of the isolates was determined by the Kirby-Bauer disc-diffusion test. The isolates were characterized into biotypes using the API 20E kit, and results were analyzed using the chi-square test. Seventy-five (32.6%) of the 230 specimens were positive for S. Typhimurium, with pigs and abattoir drains presenting the highest level of isolation (40%). Biochemical typing grouped the isolates into five biotypes. Biotype I was the most prevalent (30.6%) while biotype IV was the least prevalent (9.3%) and was absent in samples from pigs. Antibiotic susceptibility studies revealed 14 antibiotypes based on antibiotics used in the study. The predominant antibiotype AMXR DOXRCEFR was recorded in 13 (17.3%) of the isolates. Multidrug resistance (to four or more antibiotics) was recorded in 50.7% (38/75) of the isolates. The most active drugs were ciprofloxacin (98.6%), ofloxacin (93.3%), amikacin (90.6%), and gentamicin (84%). All the isolates (100%) were resistant to tetracycline and ampicillin. Cattle and pigs were found to be reservoirs of S. Typhimurium in the environment of Buea, Cameroon, implying that foods from these sources, if not properly handled, could serve as vehicles for its transmission to humans

Malaria infection and anaemia in HIV-infected children in Mutengene, Southwest Cameroon: a cross sectional study

BACKGROUND: Malaria is one of the leading causes of morbidity and mortality in children and HIV infection as well as other factors may worsen the situation. This study was aimed at determining the factors influencing malaria parasite prevalence and density as well as anaemia in HIV-infected children in Mutengene, Cameroon from November, 2012 to April, 2013. METHODS: A semi-structured questionnaire was used to record information on socio-demographic factors and use of preventive measures by caregivers of HIV-infected children aged 1–15 years and of both sexes. Venous blood was collected; blood films were prepared and Giemsa-stained for parasite detection and speciation. Haemoglobin concentration was measured and the anaemic status determined. Data was analysed using Epi Info 7 software. RESULTS: A total of 234 children were studied. The overall malaria parasite prevalence was 24.8 % (58) and was significantly higher (31.9 %, P = 0 .004) in females, those who did not implement any preventive measure at all (66.7 %, P = 0.03) and children who used antiretroviral therapy (ART) (28.6 %, P = 0.02) when compared with their respective counterparts. Geometric mean parasite density (GMPD) was significantly higher (3098.4, P = 0.02) in children who presented with fever, had CD4 T cells ≥500 cells/μL (491.3, P = 0.003) and those with moderate anaemia (1658.8, P = 0.03) than their respective counterparts. Although there was no significant difference, GMPD was however higher in males (549.0); those not on ART (635.0) and highest in children <5 years old (633.0) than their respective counterparts. The overall prevalence of anaemia was 49.6 % (116). The value was significantly highest (58.3 %, P = 0.01) in the 11–15 years age group; those with CD4 T cell level 200–499 (72.7 %, P = 0.001) and children with fever (85.7 %, P = 0.01). CONCLUSION: Implementation of proper and integrated malaria preventive measures as well as frequent monitoring of anaemia on prescription of ART could likely improve the health conditions of HIV-infected children thus avoiding malaria-related morbidity and mortality

Risk Factors for African Tick-Bite Fever in Rural Central Africa

African tick-bite fever is an emerging infectious disease caused by the spotted fever group Rickettsia, Rickettsia africae, and is transmitted by ticks of the genus Amblyomma. To determine the seroprevalence of exposure to R. africae and risk factors associated with infection, we conducted a cross-sectional study of persons in seven rural villages in distinct ecological habitats of Cameroon. We examined 903 plasma samples by using an indirect immunofluorescence assay for antibodies to R. africae and analyzed demographic and occupational data collected from questionnaires. Of the 903 persons tested, 243 (26.9%) had IgG/IgM/IgA reactive with R. africae. Persons from four of the seven village sites were significantly more likely to be seropositive (P < 0.05), and lowland forest sites tended to have higher seroprevalences. These results suggest that African tick-bite fever is common in adults in rural areas of Cameroon and that ecological factors may play a role in the acquisition of R. africae infection

DNA Sequence Analysis of South African Helicobacter pylori Vacuolating Cytotoxin Gene (vacA)

Sequence diversity and population structures can vary widely among pathogenic bacteria species. In some species, all isolates are highly similar, whereas in others most of the isolates are distinguished easily. H. pylori is known for its wide genetic diversity amongst the various strains most especially in the genes involved in virulence. The aim of this study was to evaluate by PCR and sequence analysis, the genetic profile of H. pylori vacA gene (s1, s2, m1 and m2). We sequenced small DNA segments from 13 vacAs1, 10 vacAm2, 6 vacAm1 and 6 vacAs2 strains which were amplified with amplicon size of 259/286 bp, 290 bp and 352 bp for vacAs1/s2, m1 and m2 respectively. Based on similarities among our strains accession numbers were provided for seven vacAs1 (HQ709109–HQ709115), six vacAs2 (JN848463–JN848468), six vacAm1 (JN848469–JN848474) and six vacAm2 (HQ650801–HQ650806) strains. Amongst the strains studied, 98.07%, 98.58%, 97.38% and 95.41% of vacAs1, vacAs2, vacAm1 and vacAm2 of the strains were conserved respectively. Findings of this study underscores the importance of understanding the virulence composition and diversity of H. pylori in South Africa for enhanced clinico-epidemiological monitoring and pathophysiology of disease

Bovine tuberculosis antemortem diagnostic test agreement and disagreement in a naturally infected African cattle population.

The interferon-gamma (IFN-γ) assay and single comparative cervical skin test (SCITT) are used to estimate bovine tuberculosis (bTB) prevalence globally. Prevalence estimates of bTB, caused by Mycobacterium bovis, are poorly quantified in many Sub-Saharan African (SSA) cattle populations. Furthermore, antemortem diagnostic performance can vary at different stages of bTB pathogenesis and in different cattle populations. In this study, we aim to explore the level of agreement and disagreement between the IFN-γ assay and SCITT test, along with the drivers for disagreement, in a naturally infected African cattle population. In, 2013, a pastoral cattle population was sampled using a stratified clustered cross-sectional study in Cameroon. A total of 100 pastoral cattle herds in the North West Region (NWR) and the Vina Division (VIN) were sampled totalling 1,448 cattle. Individual animal data and herd-level data were collected, and animals were screened using both the IFN-γ assay and SCITT. Serological ELISAs were used to detect exposure to immunosuppressing co-infections. Agreement analyses were used to compare the performance between the two bTB diagnostic tests, and multivariable mixed-effects logistic regression models (MLR) were developed to investigate the two forms of IFN-γ assay and SCITT binary disagreement. Best agreement using the Cohen's κ statistic, between the SCITT (>2 mm) and the IFN-γ assay implied a ‘fair-moderate' agreement for the NWR [κ = 0.42 (95%CI: 0.31–0.53)] and ‘poor-moderate' for the VIN [κ = 0.33 (95% CI: 0.18–0.47)]. The main test disagreement was the animals testing positive on the IFN-γ assay and negative by the SCITT. From MLR modeling, adults (adults OR: 7.57; older adults OR = 7.21), females (OR = 0.50), bovine leucosis (OR = 2.30), and paratuberculosis positivity (OR = 6.54) were associated with IFN-γ-positive/SCITT-negative disagreement. Subsets to investigate diagnostic test disagreement for being SCITT-positive and IFN-γ-negative also identified that adults (adults OR = 15.74; older adults OR = 9.18) were associated with IFN-γ-negative/SCITT-positive disagreement. We demonstrate that individual or combined use of the IFN-γ assay and SCITT can lead to a large variation in bTB prevalence estimates. Considering that animal level factors were associated with disagreement between the IFN-γ assay and SCITT in this study, future work should further investigate their impact on diagnostic test performance to develop the approaches to improve SSA prevalence estimates

Seroepidemiology of Crimean-Congo Haemorrhagic Fever among cattle in Cameroon:Implications from a One Health perspective

BACKGROUND: Crimean-Congo Haemorrhagic Fever (CCHF) is a tick-borne viral zoonotic disease distributed across several continents and recognized as an ongoing health threat. In humans, the infection can progress to a severe disease with high fatality, raising public health concerns due to the limited prophylactic and therapeutic options available. Animal species, clinically unaffected by the virus, serve as viral reservoirs and amplifier hosts, and can be a valuable tool for surveillance. Little is known about the occurrence and prevalence of Crimean-Congo Haemorrhagic Fever Virus (CCHFV) in Cameroon. Knowledge on CCHFV exposure and the factors associated with its presence in sentinel species are a valuable resource to better understand transmission dynamics and assess local risks for zoonotic disease emergence. METHODS AND FINDINGS: We conducted a CCHFV serological survey and risk factor analysis for animal level seropositivity in pastoral and dairy cattle in the North West Region (NWR) and the Vina Division (VD) of the Adamawa Region in Cameroon. Seroprevalence estimates were adjusted for sampling design-effects and test performance. In addition, explanatory multivariable logistic regression mixed-effects models were fit to estimate the effect of animal characteristics, husbandry practices, risk contacts and ecological features on the serological status of pastoral cattle. The overall seroprevalence was 56.0% (95% CI 53.5–58.6) and 6.7% (95% CI 2.6–16.1) among pastoral and dairy cattle, respectively. Animals going on transhumance had twice the odds of being seropositive (OR 2.0, 95% CI 1.1–3.8), indicating that animal movements could be implicated in disease expansion. From an ecological perspective, absolute humidity (OR 0.6, 95% CI 0.4–0.9) and shrub density (OR 2.1, 95% CI 1.4–3.2) were associated with seropositivity, which suggests an underlying viral dynamic connecting vertebrate host and ticks in a complex transmission network. CONCLUSIONS: This study demonstrated high seroprevalence levels of CCHFV antibodies in cattle in Cameroon indicating a potential risk to human populations. However, current understanding of the underlying dynamics of CCHFV locally and the real risk for human populations is incomplete. Further studies designed using a One Health approach are required to improve local knowledge of the disease, host interactions and environmental risk factors. This information is crucial to better project the risks for human populations located in CCHFV-suitable ecological niches