Characterization of Salmonella enterica from invasive bloodstream infections and water sources in rural Ghana.

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

Antibiotic resistance and clonal diversity of invasive Staphylococcus aureus in the rural Ashanti Region, Ghana.

BACKGROUND: Staphylococcus aureus is among the most common pathogens isolated from blood cultures in Ghana; yet the epidemiology of blood infections in rural settings is poorly described. This study aims to investigate antimicrobial susceptibility and clonal diversity of S. aureus causing bloodstream infections in two hospitals in the Ashanti Region, Ghana. METHODS: Blood cultures were performed for all febrile patients (≥37.5 °C) on hospital admission. Antibiotic susceptibility testing for S. aureus isolates was carried out by the VITEK 2 system. Multiplex polymerase chain reaction (PCR) was used to detect S. aureus-specific nuc gene, Panton-Valentine leukocidin (PVL), and methicillin-resistant S. aureus (MRSA)-specific mecA and mecC genes. The population structure of S. aureus was assessed by spa typing. RESULTS: In total, 9,834 blood samples were cultured, out of which 0.6% (n = 56) were positive for S. aureus. Multidrug resistance (MDR) was detected in 35.7% (n = 20) of the S. aureus strains, of which one was a MRSA. The highest rate of antibiotic resistance was seen for commonly available antibiotics, including penicillin (n = 55; 98.2%), tetracycline (n = 32; 57.1%) and trimethoprim/sulfamethoxazole (n = 26; 46.4%). Of all S. aureus strains, 75.0% (n = 42) carried the PVL-encoding genes. We found 25 different spa types with t355 (n = 11; 19.6%), t314 (n = 8; 14.3%), t084 (n = 8; 14.3%) and t311 (n = 5; 8.9%) being predominant. CONCLUSION: The study exhibited an alarmingly large level of antibiotic resistance to locally available antibiotics. The frequency of genetically diverse and PVL-positive methicillin-sensitive S. aureus (MSSA) was high and could represent a reservoir for the emergence of virulent PVL-positive MRSA clones

Classification of invasive bloodstream infections and Plasmodium falciparum malaria using autoantibodies as biomarkers.

Funder: Projekt DEALA 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

Drinking water from dug wells in rural ghana--salmonella contamination, environmental factors, and genotypes.

Salmonellosis is an important but neglected disease in sub-Saharan Africa. Food or fecal-oral associated transmissions are the primary cause of infections, while the role of waterborne transmission is unclear. Samples were collected from different dug wells in a rural area of Ghana and analyzed for contamination with bacteria, and with Salmonella in particular. In addition, temporal dynamics and riks factors for contamination were investigated in 16 wells. For all Salmonella isolates antibiotic susceptibility testing was performed, serovars were determined and strains from the same well with the same serovar were genotyped. The frequency of well water contamination with Gram-negative rod-shaped bacteria was 99.2% (n = 395). Out of 398 samples, 26 (6.5%) tested positive for Salmonella spp. The serovar distribution was diverse including strains not commonly isolated from clinical samples. Resistance to locally applied antibiotics or resistance to fluoroquinolones was not seen in the Salmonella isolates. The risk of Salmonella contamination was lower in wells surrounded by a frame and higher during the rainy season. The study confirms the overall poor microbiological quality of well water in a resource-poor area of Ghana. Well contamination with Salmonella poses a potential threat of infection, thus highlighting the important role of drinking water safety in infectious disease control

16S rRNA Gene Sequence-Based Identification of Bacteria in Automatically Incubated Blood Culture Materials from Tropical Sub-Saharan Africa.

BACKGROUND: The quality of microbiological diagnostic procedures depends on pre-analytic conditions. We compared the results of 16S rRNA gene PCR and sequencing from automatically incubated blood culture materials from tropical Ghana with the results of cultural growth after automated incubation. METHODS: Real-time 16S rRNA gene PCR and subsequent sequencing were applied to 1500 retained blood culture samples of Ghanaian patients admitted to a hospital with an unknown febrile illness after enrichment by automated culture. RESULTS: Out of all 1500 samples, 191 were culture-positive and 98 isolates were considered etiologically relevant. Out of the 191 culture-positive samples, 16S rRNA gene PCR and sequencing led to concordant results in 65 cases at species level and an additional 62 cases at genus level. PCR was positive in further 360 out of 1309 culture-negative samples, sequencing results of which suggested etiologically relevant pathogen detections in 62 instances, detections of uncertain relevance in 50 instances, and DNA contamination due to sample preparation in 248 instances. In two instances, PCR failed to detect contaminants from the skin flora that were culturally detectable. Pre-analytical errors caused many Enterobacteriaceae to be missed by culture. CONCLUSIONS: Potentially correctable pre-analytical conditions and not the fastidious nature of the bacteria caused most of the discrepancies. Although 16S rRNA gene PCR and sequencing in addition to culture led to an increase in detections of presumably etiologically relevant blood culture pathogens, the application of this procedure to samples from the tropics was hampered by a high contamination rate. Careful interpretation of diagnostic results is required

Fluoroquinolone-Resistant Salmonella enterica, Campylobacter spp., and Arcobacter butzleri from Local and Imported Poultry Meat in Kumasi, Ghana

Salmonella and Campylobacter are important gastroenteric pathogens. Arcobacter butzleri is an emerging enteric pathogen. Data on the frequencies of these poultry-associated pathogens on meat products sold in sub-Saharan Africa are scarce. This study aimed to analyze the frequency of Salmonella, Campylobacter, and Arcobacter antibiotic resistance and underlying mechanisms of resistance to fluoroquinolones in locally produced and imported poultry sold in urban Ghana. Chicken meat was collected and cultured on standard media. Bacterial strains were identified by biochemical methods and by mass spectrometry. Antibiotic susceptibility was tested by disk diffusion. Ciprofloxacin-resistant strains were assessed for molecular mechanisms of resistance. Among 200 samples, comprising 34% (n = 68) from the Ghanaian poultry industry and 66% (n = 132) from imports, 9% (n = 17) contained Salmonella, 11% (n = 22) Campylobacter, and 26.5% (n = 53) A. butzleri. Higher overall contamination frequencies were found in local meat. Most common Salmonella serovars identified were Kentucky (n/N = 5/16; 31%) and Poona (n/N = 4/16; 25%). Campylobacter were C. coli (n/N = 10/19; 53%) and C. jejuni (n/N = 9/19; 47%). Resistance to fluoroquinolones was high with 63% (n = 10), 75% (n = 15), and 52% (n = 25) in Salmonella, Campylobacter, and Arcobacter, respectively. A link between Salmonella Kentucky [sequence type (ST) 198] and a ciprofloxacin minimum inhibitory concentration of 16 μg/mL was found. Salmonella Poona-ST308 revealed transferable qnrB2 fluoroquinolone resistance genes. Markedly high frequencies of resistant Salmonella, Campylobacter, and Arcobacter predominant in locally produced meat represent a probable transmission reservoir for human infections. These findings highlight the need for implementation of surveillance systems that focus on food hygiene, use of antibiotics in animal husbandry, and continuous monitoring of the quality of meat products from imports.Peer Reviewe

Pathogens associated with hospitalization due to acute lower respiratory tract infections in children in rural Ghana : a case–control study

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

Malaria Coinfections in Febrile Pediatric Inpatients: A Hospital-Based Study From Ghana

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

Characterization of Salmonella enterica from invasive bloodstream infections and water sources in rural Ghana

Abstract 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