Browsing by Author "Krumkamp Ralf"

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    Characterization of Salmonella enterica from invasive bloodstream infections and water sources in rural Ghana
    (BioMed Central, 2018) Dekker Denise; Krumkamp Ralf; Eibach Daniel; Owusu-Dabo Ellis; Sarpong Nimako...et al
    Background: Non-typhoidal Salmonella (NTS) cause the majority of bloodstream infections in Ghana, however the mode of transmission and source of invasive NTS in Africa are poorly understood. This study compares NTS from water sources and invasive bloodstream infections in rural Ghana. Methods: Blood from hospitalised, febrile children and samples from drinking water sources were analysed for Salmonella spp. Strains were serotyped to trace possible epidemiological links between human and water-derived isolates.. Antibiotic susceptibility testing was performed, Results: In 2720 blood culture samples, 165 (6%) NTS were isolated. S. Typhimurium (70%) was the most common serovar followed by S. Enteritidis (8%) and S. Dublin (8%). Multidrug resistance (MDR) was found in 95 (58%) NTS isolates, including five S. Enteritidis. One S. Typhimurium showed reduced fluroquinolone susceptibility. In 511 water samples, 19 (4%) tested positive for S. enterica with two isolates being resistant to ampicillin and one isolate being resistant to cotrimoxazole. Serovars from water samples were not encountered in any of the clinical specimens. Conclusion: Water analyses demonstrated that common drinking water sources were contaminated with S. enterica posing a potential risk for transmission. However, a link between S. enterica from water sources and patients could not be established, questioning the ability of water-derived serovars to cause invasive bloodstream infections.
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    Classifcation of invasive bloodstream infections and Plasmodium falciparum malaria using autoantibodies as biomarkers
    (Springer Nature, 2020) Krumkamp Ralf; Struck Sunaina Nicole; Owusu-Dabo Ellis; Lorenz Eva; Zimmermann Marlow...et al; 0000-0003-4232-4292
    A better understanding of disease-specific biomarker profiles during acute infections could guide the development of innovative diagnostic methods to differentiate between malaria and alternative causes of fever. We investigated autoantibody (AAb) profiles in febrile children (≤ 5 years) admitted to a hospital in rural Ghana. Serum samples from 30 children with a bacterial bloodstream infection and 35 children with Plasmodium falciparum malaria were analyzed using protein microarrays (Protoplex Immune Response Assay, ThermoFisher). A variable selection algorithm was applied to identify the smallest set of AAbs showing the best performance to classify malaria and bacteremia patients. The selection procedure identified 8 AAbs of which IFNGR2 and FBXW5 were selected in repeated model run. The classification error was 22%, which was mainly due to non-Typhi Salmonella (NTS) diagnoses being misclassified as malaria. Likewise, a cluster analysis grouped patients with NTS and malaria together, but separated malaria from non-NTS infections. Both current and recent malaria are a risk factor for NTS, therefore, a better understanding about the function of AAb in disease-specific immune responses is required in order to support their application for diagnostic purposes.
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    Malaria Coinfections in Febrile Pediatric Inpatients: A Hospital-Based Study From Ghana
    (Clinical Infectious Diseases, 2018) Hogan Benedikt; Eibach Daniel; Owusu-Dabo Ellis; Krumkamp Ralf; Sarpong Nimako....et al
    Background. The epidemiology of pediatric febrile illness is shifting in sub-Saharan Africa, but malaria remains a major cause of childhood morbidity and mortality. The present study describes causes of febrile illness in hospitalized children in Ghana and aims to determine the burden of malaria coinfections and their association with parasite densities. Methods. In a prospective study, children (aged ≥30 days and ≤15 years) with fever ≥38.0°C were recruited after admission to the pediatric ward of a primary hospital in Ghana. Malaria parasitemia was determined and blood, stool, urine, respiratory, and cerebrospinal fluid specimens were screened for parasitic, bacterial, and viral pathogens. Associations of Plasmodium densities with other pathogens were calculated. Results. From November 2013 to April 2015, 1238 children were enrolled from 4169 admissions. A clinical/microbiological diagnosis could be made in 1109/1238 (90%) patients, with Plasmodium parasitemia (n = 728/1238 [59%]) being predominant. This was followed by lower respiratory tract infections/pneumonia (n = 411/1238 [34%]; among detected pathogens most frequently Streptococcus pneumoniae, n = 192/299 [64%]), urinary tract infections (n = 218/1238 [18%]; Escherichia coli, n = 21/32 [66%]), gastrointestinal infections (n = 210 [17%]; rotavirus, n = 32/97 [33%]), and invasive bloodstream infections (n = 62 [5%]; Salmonella species, n = 47 [76%]). In Plasmodium-infected children the frequency of lower respiratory tract, gastrointestinal, and bloodstream infections increased with decreasing parasite densities. Conclusions. In a hospital setting, the likelihood of comorbidity with a nonmalarial disease is inversely correlated with increas ing blood levels of malaria parasites. Hence, parasite densities provide important information as an indicator for the probability of coinfection, in particular to guide antimicrobial medication
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    Pathogens associated with hospitalization due to acute lower respiratory tract infections in children in rural Ghana: a case–control study
    (Springer Nature, 2023) Krumkamp Ralf; Kohsar Matin; Owusu-Dabo Ellis; Nolte Kolja...et al; 0000-0003-4232-4292
    Respiratory infections are one of the most common causes of death among children under the age of five years. Data on prevalence and relevance of specific organisms in African children are still lacking. This case–control-study investigated prevalence and relevance of specific organisms in Ghanaian children admitted to hospital with symptoms of lower respiratory tract infection (LRTI). Pharyngeal swabs were taken and tested by PCR for 19 respiratory isolates. Adjusted odds ratios (aORs) were calculated to estimate associations between isolates and admission with LRTI. Population attributable fractions (PAFs) were calculated to assess the proportion of LRTI cases due to a particular pathogen. The study included 327 cases and 562 controls. We found associations between detection and admission for LRTI for influenza (aOR 98.6; 95% confidence interval (CI) 20.0–1789.6), respiratory syncytial virus (aOR 40.2; 95% CI 7.2–758.6), H. influenzae (aOR 4.1; 95% CI 2.2–7.9) and S. pneumoniae (aOR 2.4; 95% CI 1.7–3.4). PAFs ≥ 10% were observed for S. pneumoniae (30%; 95% CI 26–42), H. influenzae (10%; 95% CI 2–19) and influenza (10%; 95% CI 2–18). This study highlights the need for heightened surveillance and development of effective vaccines for respiratory pathogens other than SARS-CoV-2 in the future.
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    Spatial heterogeneity of malaria in Ghana: a cross-sectional study on the association between urbanicity and the acquisition of immunity
    (BioMed Central, 2016) Frank Clemens; Krumkamp Ralf; Owusu-Dabo Ellis; Sarpong Nimako; Sothmann Peter......et al
    Background: Malaria incidence has declined considerably over the last decade. This is partly due to a scale-up of control measures but is also attributed to increasing urbanization. This study aimed to analyse the association between malaria and urbanization and the effect of urbanicity on the acquisition of semi-immunity. Methods: In 2012, children with fever presenting to St Michael’s Hospital Pramso/Ghana were recruited. The malaria positive-fraction (MPF) of fever cases was calculated on community-level to approximate the malaria risk. The mean age of malaria cases was calculated for each community to estimate the acquisition of semi-immunity. The level of urbanicity for the communities was calculated and associations between MPF, urbanicity and immunity were modelled using linear regression. Results: Twenty-six villages were included into the study with a mean MPF of 35 %. A linear decrease of 5 % (95 % CI: 4–6 %) in MPF with every ten-point increase in urbanicity was identified. The mean age of malaria patients increased by 2.9 months (95 % CI: 1.0–4.8) with every ten-point increase in urbanicity. Discussion: The results confirm an association between an increase in urbanicity and declining malaria risk and dem‑ onstrate that the acquisition of semi-immunity is heterogeneous on a micro-epidemiological scale and is associated with urbanicity
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    Spectrum of antibiotic resistant bacteria and fungi isolated from chronically infected wounds in a rural district hospital in Ghana
    (PLOS ONE, 2020) Krumkamp Ralf; Oppong Kwabena; Owusu-Dabo Ellis; Hogan Benedikt; Strauss Ricardo; Frickmann Hagen....et al
    Background Chronic infected wounds are generally difficult to manage and treatment can be particularly challenging in resource-limited settings where diagnostic testing is not readily available. In this study, the epidemiology of microbial pathogens in chronically infected wounds in rural Ghana was assessed to support therapeutic choices for physicians. Methods Culture-based bacterial diagnostics including antimicrobial resistance testing were per formed on samples collected from patients with chronic wounds at a hospital in Asante Akim North Municipality, Ghana. Fungal detection was performed by broad-range fungal PCR and sequencing of amplicons. Results In total, 105 patients were enrolled in the study, from which 207 potential bacterial patho gens were isolated. Enterobacteriaceae (n = 84, 41%) constituted the most frequently iso lated group of pathogens. On species level, Pseudomonas aeruginosa (n = 50, 24%) and Staphylococcus aureus (n = 28, 14%) were predominant. High resistance rates were docu mented, comprising 29% methicillin resistance in S. aureus as well as resistance to 3rd gen eration cephalosporins and fluoroquinolones in 33% and 58% of Enterobacteriaceae, respectively. One P. aeruginosa strain with carbapenem resistance was identified. The most frequently detected fungi were Candida tropicalis.
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    Urbanicity and Paediatric Bacteraemia in Ghana—A Case-Control Study within a Rural Urban Transition Zone
    (PLOS ONE, 2015) Sothmann Peter; Krumkamp Ralf; Kreuels Benno; Owusu-Dabo Ellis; Fobil Julius; Jaeger Anna....et al
    Background Systemic bacterial infections are a major cause of paediatric febrile illness in sub-Saharan Africa. Aim of this study was to assess the effects of social and geographical determinants on the risk of bacteraemia in a rural-urban transition zone in Ghana. Methods Children below 15 years of age with fever were recruited at an outpatient department in the suburban belt of Kumasi, Ghana’s second largest city. Blood was taken for bacterial culture and malaria diagnostics. The socio-economic status of participants was calculated using Principle Component Analysis. A scale, based on key urban characteristics, was estab lished to quantify urbanicity for all communities in the hospital catchment area. A case-con trol analysis was conducted, where children with and without bacteraemia were cases and controls, respectively. Results Bacteraemia was detected in 72 (3.1%) of 2,306 hospital visits. Non-typhoidal Salmonella (NTS; n = 24; 33.3%) and Salmonella typhi (n = 18; 25.0%) were the most common isolates. Logistic regression analysis showed that bacteraemia was negatively associated with urbanicity (odds ratio [OR] = 0.8; 95% confidence interval [CI]: 0.7–1.0) and socio-eco nomic status (OR = 0.8; 95% CI: 0.6–0.9). Both associations were stronger if only NTS infections were used as cases (OR = 0.5; 95% CI: 0.3–0.8 and OR = 0.6; 95% CI: 0.4–1.0, respectively).
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    Urbanicity and Paediatric Bacteraemia in Ghana—A Case-Control Study within a Rural Urban Transition Zone
    (PLOS ONE, 2015) Sothmann Peter; Krumkamp Ralf; Kreuels Benno; Owusu-Dabo Ellis; Gyau Kennedy; Fobil Julius.....et al
    Systemic bacterial infections are a major cause of paediatric febrile illness in sub-Saharan Africa. Aim of this study was to assess the effects of social and geographical determinants on the risk of bacteraemia in a rural-urban transition zone in Ghana. Methods Children below 15 years of age with fever were recruited at an outpatient department in the suburban belt of Kumasi, Ghana’s second largest city. Blood was taken for bacterial culture and malaria diagnostics. The socio-economic status of participants was calculated using Principle Component Analysis. A scale, based on key urban characteristics, was estab lished to quantify urbanicity for all communities in the hospital catchment area. A case-con trol analysis was conducted, where children with and without bacteraemia were cases and controls, respectively. Results Bacteraemia was detected in 72 (3.1%) of 2,306 hospital visits. Non-typhoidal Salmonella (NTS; n = 24; 33.3%) and Salmonella typhi (n = 18; 25.0%) were the most common isolates. Logistic regression analysis showed that bacteraemia was negatively associated with urbanicity (odds ratio [OR] = 0.8; 95% confidence interval [CI]: 0.7–1.0) and socio-eco nomic status (OR = 0.8; 95% CI: 0.6–0.9). Both associations were stronger if only NTS infections were used as cases (OR = 0.5; 95% CI: 0.3–0.8 and OR = 0.6; 95% CI: 0.4–1.0, respectively).