Papers by alex owusu-ofori
Clinical Microbiology and Infection
BMC Infectious Diseases, 2021
Background Pneumococcal vaccine immunizations may be responsible for alterations in serotype epid... more Background Pneumococcal vaccine immunizations may be responsible for alterations in serotype epidemiology within a region. This study investigated the pneumococcal carriage prevalence and the impact of the 13-valent pneumococcal conjugate vaccine (PCV-13) on circulating serotypes among healthy children in Northern Ghana. Methods This was a cross sectional study conducted in the Kassena-Nankana districts of Northern Ghana from November to December during the dry season of 2018. Nasopharyngeal swabs collected from 193 participants were cultured per standard microbiological protocols and pneumococcal isolates were serotyped using the latex agglutination technique and the capsular Quellung reaction test. We examined for any association between the demographic characteristics of study participants and pneumococcal carriage using chi-square test and logistic regression. Results Of the 193 participants that were enrolled the mean age was 8.6 years and 54.4% were females. The carriage rate ...
Background Malaria remains an important public health threat claiming many lives particularly in ... more Background Malaria remains an important public health threat claiming many lives particularly in Sub-Saharan Africa. Light microscopy which is a blood-based test is the Gold standard for laboratory diagnosis of malaria in the clinical settings. The lack of sensitivity of Microscopy coupled with the challenges associated with blood sampling necessitates exploring alternative methods of identifying malaria cases. Aims and Objectives The aim of this study was to detect the presence of Plasmodium Lactate Dehydrogenase (pLDH) and Plasmodium falciparum Histidine-Rich Protein 2 (PfHRP2) in the saliva of suspected malaria patients and to compare the diagnostic accuracy of these saliva-borne biomarkers with the results of blood film microscopy using Nested PCR as the reference test. Methods The research was a comparative study. Matched saliva and blood samples of suspected malaria patients were collected. The blood samples were aliquoted into 2 smaller volumes and used to run blood film micr...
Open Forum Infectious Diseases, 2014
The Journal of Pediatrics, 2006
Objectives To improve algorithms for the identification of children at risk of dying of malaria i... more Objectives To improve algorithms for the identification of children at risk of dying of malaria in endemic areas. Study design In a prospective study of 2446 children with severe and complicated malaria admitted to a tertiary referral center in Ghana, West Africa, 12 clinical and laboratory signs were evaluated as indicators of death. Results A prolonged (>2 seconds) capillary refill time (pCRT) was identified as an independent prognostic indicator of death along with acidosis, coma, and respiratory distress. Among the clinical signs, pCRT increased the risk of dying from 4-fold to 11-fold when present in addition to coma and respiratory distress. Conclusions The recognition of pCRT as an independent indicator of death justifies its inclusion as a defining criterion of severe and complicated malaria and improves the use of clinical examinations in the triage of patients with malaria. As pCRT has been shown to reflect circulatory disturbances in children, it should be included in upcoming studies as a possible sign to indicate the need for intravenous fluid administration.
The Journal of Clinical Pharmacology, 2003
Clinical Infectious Diseases, 2003
The burden of malaria in regions of high endemicity frequently overwhelms hospitals' capacity to ... more The burden of malaria in regions of high endemicity frequently overwhelms hospitals' capacity to provide effective care. A rapid, simple method of identifying children who are at highest risk is vital to reduce mortality among hospitalized children. Multiple regression analysis identified prognostic variables predicting mortality in severely ill children admitted to a Ghanaian teaching hospital. These variables were compared in children with and without malaria. A total of 1492 (90.2%) of 1654 severely ill children referred for assessment had evaluable outcomes. Low Blantyre coma score (BCS), high blood lactate level, and high body mass index were independent predictors of mortality among children with malaria (area under the receiver operating characteristic curve [AUC/ROC], 0.84). In children without malaria, BCS and lactate level also predicted mortality, but the addition of respiratory distress and hematocrit improved the model (AUC/ROC, 0.77). Predictors of mortality in children with malaria differ from those for other severe illnesses and reflect differences in underlying pathophysiological processes. Infection with Plasmodium falciparum afflicts ∼400 million individuals and kills 1 million children annually . In sub-Saharan Africa, more than one-half of the beds in pediatric wards may be occupied by children with severe malaria. This burden of ill children frequently overwhelms available diagnostic and treatment
Clinical Infectious Diseases, 2010
Although international policies recommend that blood for transfusion should be screened for trans... more Although international policies recommend that blood for transfusion should be screened for transfusiontransmitted infections, malaria screening is not performed in most malaria-endemic countries in sub-Saharan Africa. Our literature review identified 17 relevant studies from the period 1980-2009 and indicated that the median prevalence of malaria among 33,029 blood donors was 10.2% (range, 0.7% in Kenya to 55.0% in Nigeria). Malaria screening methods, including microscopy (used in 16 of 17 studies), are either insensitive or impractical for donor screening in resource-poor countries. Even if a suitable screening method were available, rejection of malaria-positive donors would jeopardize the blood supply. Only 1 study established the prevalence of parasitemia among transfusion recipients. This review highlights the need for more evidence about the clinical impact of transfusion-transmitted malaria to justify the policy of screening for blood for malaria in areas of endemicity and for a critical analysis of the feasibility of implementing such a policy and its effect on blood supply.
Antimicrobial Agents and Chemotherapy, 2001
We present the first population pharmacokinetic analysis of quinine in patients with Plasmodium f... more We present the first population pharmacokinetic analysis of quinine in patients with Plasmodium falciparum malaria. Ghanaian children (n = 120; aged 12 months to 10 years) with severe malaria received an intramuscular loading dose of quinine dihydrochloride (20 mg/kg of body weight). A two-compartment model with first-order absorption and elimination gave post hoc estimates for pharmacokinetic parameters that were consistent with those derived from non-population pharmacokinetic studies (clearance [CL] = 0.05 liter/h/kg of body weight; volume of distribution in the central compartment [V 1] = 0.65 liter/kg; volume of distribution at steady state = 1.41 liter/kg; half-life at β phase = 19.9 h). There were no covariates (including age, gender, acidemia, anemia, coma, parasitemia, or anticonvulsant use) that explained interpatient variability in weight-normalized CL and V 1. Intramuscular quinine was associated with minor, local toxicity in some patients (13 of 108; 12%), and 11 patien...
PLoS ONE, 2008
Background. The objective was to evaluate the safety, reactogenicity and immunogenicity of the AM... more Background. The objective was to evaluate the safety, reactogenicity and immunogenicity of the AMA-1-based blood-stage malaria vaccine FMP2.1/AS02A in adults exposed to seasonal malaria. Methodology/Principal Findings. A phase 1 double blind randomized controlled dose escalation trial was conducted in Bandiagara, Mali, West Africa, a rural town with intense seasonal transmission of Plasmodium falciparum malaria. The malaria vaccine FMP2.1/AS02A is a recombinant protein (FMP2.1) based on apical membrane antigen-1 (AMA-1) from the 3D7 clone of P. falciparum, adjuvanted with AS02A. The comparator vaccine was a cell-culture rabies virus vaccine (RabAvert). Sixty healthy, malaria-experienced adults aged 18-55 y were recruited into 2 cohorts and randomized to receive either a half dose or full dose of the malaria vaccine (FMP2.1 25 mg/AS02A 0.25 mL or FMP2.1 50 mg/AS02A 0.5 mL) or rabies vaccine given in 3 doses at 0, 1 and 2 mo, and were followed for 1 y. Solicited symptoms were assessed for 7 d and unsolicited symptoms for 30 d after each vaccination. Serious adverse events were assessed throughout the study. Titers of anti-AMA-1 antibodies were measured by ELISA and P. falciparum growth inhibition assays were performed on sera collected at pre-and post-vaccination time points. Transient local pain and swelling were common and more frequent in both malaria vaccine dosage groups than in the comparator group. Anti-AMA-1 antibodies increased significantly in both malaria vaccine groups, peaking at nearly 5-fold and more than 6-fold higher than baseline in the half-dose and full-dose groups, respectively. Conclusion/Significance. The FMP2.1/AS02A vaccine had a good safety profile, was well-tolerated, and was highly immunogenic in malaria-exposed adults. This malaria vaccine is being evaluated in Phase 1 and 2 trials in children at this site. Trial Registration. ClinicalTrials.gov NCT00308061
British Microbiology Research Journal, 2015
Background: Ghana launched its National Action Plan (NAP) to curb the spread of AMR in 2017. The ... more Background: Ghana launched its National Action Plan (NAP) to curb the spread of AMR in 2017. The current study was designed to gather data on the public perception concerning antibiotic use by surveying a population at Kejetia market in Kumasi with the aim of informing the design and implementation of public health campaigns linked to the NAP in Ghana. Method: A cross sectional study was conducted at the Kejetia market in Kumasi, Ghana between November 2017 and January 2018. Participants were adults over 18 years of age and data were gathered via a questionnaire regarding participants’ perceptions on the acquisition, use and disposal of antibiotics. Results: The number of participants was 302 of which nearly 60% were female. Statistically significant associations were identified between gender and level of education (p<0.05, Fisher’s exact test). Amoxicillin and metronidazole were the most commonly used antibiotics. Females were three times more likely to use these agents for dia...
Background: Methicillin-resistant Staphylococcus aureus (MRSA) are a major cause of hospital- an... more Background: Methicillin-resistant Staphylococcus aureus (MRSA) are a major cause of hospital- and community-acquired infection. They can colonize humans and cause a wide range of infections including pneumonia, endocarditis and bacteraemia. We investigated the molecular mechanism of resistance and virulence of MRSA isolates from a teaching hospital in Ghana. Methodology: A total of 91 S. aureus isolates constituted the initial bacterial sample. Identification of S. aureus was confirmed by the VITEK 2 system. The cefoxitin screen test was used to detect MRSA and antibiotic susceptibility was determined using the VITEK 2 system. The resistance ( mecA , blaZ , aac-aph , ermC , and tetK ) and virulence ( lukS/F-PV , hla , hld and eta ) genes were amplified by polymerase chain reaction (PCR) and positive samples subjected to DNA sequencing. Pulsed field gel electrophoresis (PFGE) was used to ascertain the relatedness of the isolates. Results: Fifty-eight of 91 (63.7%) isolates were puta...
Two novel blaDIM-1- or blaIMP-1-containing genomic islands (GIs) were discovered by whole-genome ... more Two novel blaDIM-1- or blaIMP-1-containing genomic islands (GIs) were discovered by whole-genome sequence analyses in four extensively drug-resistant (XDR) Pseudomonas aeruginosa isolates from inpatients at a tertiary hospital in Ghana. The strains were of sequence type 234 (ST234) and formed a phylogenetic clade together with ST111, which is recognized as a global high-risk clone. ABSTRACT Two novel blaDIM-1- or blaIMP-1-containing genomic islands (GIs) were discovered by whole-genome sequence analyses in four extensively drug-resistant (XDR) Pseudomonas aeruginosa isolates from inpatients at a tertiary hospital in Ghana. The strains were of sequence type 234 (ST234) and formed a phylogenetic clade together with ST111, which is recognized as a global high-risk clone. Their carbapenem resistance was encoded by two Tn402-type integrons, In1592 (blaDIM-1) and In1595 (blaIMP-1), both carrying complete tni mobilization modules. In1595 was bound by conserved 25-bp inverted repeats (IRs) ...
INTRODUCTION: Salmonella infections cause significant morbidity and mortality, especially in reso... more INTRODUCTION: Salmonella infections cause significant morbidity and mortality, especially in resource-limited countries. The situation is worsened by widespread presence of multidrug resistant (MDR) strains, largely encoded on conjugative plasmids, but with little knowledge about how these plasmids are identified especially in low-middle income countries. We present findings of various plasmid variants possibly encoding MDR salmonella from Ghana. METHODS: this was a cross-sectional study involving individuals suspected of having salmonella infection presenting at two major hospitals in Ghana. Blood, stool and oropharyngeal specimens (OPS) were taken from consenting individuals between May, 2016 and January, 2018. Identification of salmonella was done using standard microbiological procedures. Total DNA was extracted from MDR salmonella isolates and PCR-based replicon typing (PBRT) performed using 30 replicons representative of the major incompatibility groups among Enterobacteriacea...
Transfusion
BACKGROUND Despite the promise of pathogen reduction for reducing transfusion-associated adverse ... more BACKGROUND Despite the promise of pathogen reduction for reducing transfusion-associated adverse events in sub-Saharan Africa, no health-economic assessment is publicly available. STUDY DESIGN AND METHODS We developed a mathematical risk reduction model to estimate the impact of nationwide whole blood pathogen reduction in Ghana on the incidence of six infectious and one non-infectious transfusion-associated adverse events. We estimated the lifetime direct healthcare costs and disability-adjusted life years lost for each adverse event. For HIV, HCV, and HBV, we simulated disease progression using Markov models, accounting for the likelihood and timing of clinical detection and treatment. We performed probabilistic and univariate sensitivity analysis. RESULTS Adding whole blood pathogen reduction to Ghana's blood safety portfolio would avert an estimated 19,898 (11,948-27,353) adverse events and 38,491 (16,444-67,118) disability-adjusted life years annually, primarily by averting sepsis (49%) and malaria (31%) infections. One year of pathogen reduction would cost an estimated $8,037,191 ($6,381,946-$9,880,760) and eliminate $8,656,389 ($4,462,614-$13,469,448) in direct healthcare spending on transfusion-associated adverse events. We estimate a 58% probability that the addition of pathogen reduction would reduce overall direct healthcare spending. Findings were most sensitive to uncertainty in the probability that a bacterially contaminated blood donation causes sepsis. CONCLUSION Whole blood pathogen reduction would substantially reduce the burden of known transfusion-associated adverse events in Ghana and may reduce overall healthcare spending. Additional benefits not captured by this analysis may include averting secondary transmission of infectious diseases, reducing non-medical costs, and averting new or re-emerging transfusion-transmitted infections.
Transfusion
Bacterial contamination of blood components (notably platelets) remains a leading infectious risk... more Bacterial contamination of blood components (notably platelets) remains a leading infectious risk to the blood supply. There has been extensive research in high‐income countries to characterize the risk of bacterial contamination along with adoption of strategies to mitigate that risk. By contrast, related data in Africa are lacking.
JAC-Antimicrobial Resistance
Background Actionable data on antimicrobial use is important when planning strategic intervention... more Background Actionable data on antimicrobial use is important when planning strategic interventions such as antimicrobial stewardship to address the challenge of drug resistance, particularly in resource-constrained settings. Objectives To assess the prevalence of antibiotic use, the pattern of commonly used antibiotics and patient factors that may be associated with the increased use of antibiotics in the study hospitals. Methods This was a cross-sectional study conducted using the WHO Methodology for Point Prevalence Surveys in hospitals. Chi-squared analysis, Fisher’s exact test and logistic regression were employed to analyse statistically the data obtained. Results The overall prevalence of antibiotic use in the hospitals was 60.5%. The commonest indications for antibiotic recommendations were community-acquired infections (36.5%), surgical prophylaxis (26.1%) and hospital-acquired infections (15.7%), among others. Very few (2.7%) of the patients had their samples taken for cult...
International Journal of Infectious Diseases
PLOS ONE
Background Plasmodium infection among children is a serious public health problem. Asymptomatic m... more Background Plasmodium infection among children is a serious public health problem. Asymptomatic malaria infection among humans serves as a significant reservoir for transmitting Plasmodium to uninfected Anopheles mosquitoes, fueling malaria endemicity and asymptomatic malaria may progress to clinical malaria. Therefore, prompt and accurate diagnosis of malaria infection is crucial for the management and control of malaria, especially in endemic areas. This study assessed the point prevalence of asymptomatic malaria infection and evaluated the performance of malaria Rapid Diagnostic Tests (RDT), light microscopy and nested PCR (nPCR) for the diagnosis of asymptomatic malaria infection in a paediatric population in the Atwima Nwabiagya North district, Ghana. Methods This cross-sectional study enrolled 500 asymptomatic children aged ≤ 5 years. After consent was obtained from a parent, blood samples were collected from each participant to assess for Plasmodium infection based on histidine rich protein-2 (pfHRP-2)-based malaria RDT, light microscopy and nPCR. Results The point prevalence of asymptomatic malaria by microscopy, RDT, and nPCR were 116/500 (23.2%), 156/500 (31.2%), and 184/500 (36.8%), respectively. Using nPCR as the reference, RDT presented with a perfect sensitivity (100.0%), specificity (100.0%), accuracy (100.0%), and reliability (100.0%) in detecting asymptomatic P. falciparum infection. Likewise, microscopy presented with an excellent specificity and high accuracy in detecting both P. falciparum (100.0%; 85.6%) and P. malariae (100.0%; 100.0%). However, the sensitivity (56.4%) and reliability (56.4%) of microscopy was low for both P. falciparum. Conclusion The findings of this study indicate a high point prevalence of asymptomatic Plasmodium infection among children in Atwima Nwabiagya North district, Ghana. In the absence of the more sensitive PCR, pfHRP-2-based malaria RDT provides substantial diagnostic sensitivity, specificity, accuracy and reliability and is superior to microscopy.
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Papers by alex owusu-ofori