Emergence of trimethoprim resistance gene dfrG in Staphylococcus aureus causing human infection and colonization in sub-Saharan Africa and its import to Europe.

OBJECTIVES: Co-trimoxazole (trimethoprim/sulfamethoxazole) is clinically valuable in treating skin and soft tissue infections (SSTIs) caused by community-associated methicillin-resistant Staphylococcus aureus (MRSA). The genetic basis of emerging trimethoprim/sulfamethoxazole resistance in S. aureus from Africa is unknown. Such knowledge is essential to anticipate its further spread. We investigated the molecular epidemiology of trimethoprim resistance in S. aureus collected in and imported from Africa. METHODS: Five hundred and ninety-eight human S. aureus isolates collected at five locations across sub-Saharan Africa [Gabon, Namibia, Nigeria (two) and Tanzania] and 47 isolates from travellers treated at six clinics in Europe because of SSTIs on return from Africa were tested for susceptibility to trimethoprim, sulfamethoxazole and trimethoprim/sulfamethoxazole, screened for genes mediating trimethoprim resistance in staphylococci [dfrA (dfrS1), dfrB, dfrG and dfrK] and assigned to spa genotypes and clonal complexes. RESULTS: In 313 clinical and 285 colonizing S. aureus from Africa, 54% of isolates were resistant to trimethoprim, 21% to sulfamethoxazole and 19% to trimethoprim/sulfamethoxazole. We found that 94% of trimethoprim resistance was mediated by the dfrG gene. Of the 47 S. aureus isolates from travellers with SSTIs, 27 (57%) were trimethoprim resistant and carried dfrG. Markers of trimethoprim resistance other than dfrG were rare. The presence of dfrG genes in S. aureus was neither geographically nor clonally restricted. CONCLUSIONS: dfrG, previously perceived to be an uncommon cause of trimethoprim resistance in human S. aureus, is widespread in Africa and abundant in imported S. aureus from ill returning travellers. These findings may foreshadow the loss of trimethoprim/sulfamethoxazole for the empirical treatment of SSTIs caused by community-associated MRSA.

High incidence of carbapenemase-producing Pseudomonas aeruginosa clinical isolates from Lagos, Nigeria.

Background: Carbapenem-resistant Pseudomonas aeruginosa strains are on the rise worldwide. This study characterized clinical isolates of P. aeruginosa from three Nigerian hospitals for carbapenem resistance. Methods: Strains isolated from wounds (n = 88), urine/catheter tips (n = 25), sputum/tracheotomy aspirates (n = 5), ear swabs (n = 4) and vaginal swabs (n = 1) were identified by MALDI-TOF and antibiotic susceptibility testing was performed using the VITEK 2 system. The genomic DNA of each isolate was subject to sequencing using Illumina and Oxford nanopore technology. Bioinformatics analyses were performed to detect antimicrobial resistance genes, clonal affiliations and phylogenetic relations of 123 non-duplicate P. aeruginosa isolates, whereas assembly of the nanopore reads using the plasmIDent pipeline enabled the identification of plasmids. Results: Forty-three percent of the isolates were resistant to all antibiotic categories tested. More than 40% of the isolates were resistant to the carbapenems imipenem and/or meropenem (39% and 44%, respectively). Among the meropenem-resistant isolates, 48 (89%) carried at least one carbapenemase gene. The predominant one was bla NDM-1 (n = 34), which conferred resistance to all five antibiotic categories and highly increased the MICs of both meropenem and imipenem. The other recurrent carbapenemase genes were bla VIM-2 (n = 4), and bla VIM-5-like (n = 11), which co-existed with bla NDM-1 in two isolates. Conclusions: The study revealed a high rate of carbapenem resistance and conjugative, broad host range plasmids carrying carbapenemase-encoding genes, especially the NDM-1 type, among isolates of P. aeruginosa. This may forebode the emergency of ubiquitous carbapenem resistance urging the implementation of infection control and antimicrobial stewardship strategies in Nigerian hospitals.

A multicentre point prevalence study of antibiotics utilization in hospitalized patients in an urban secondary and a tertiary healthcare facilities in Nigeria: findings and implications.

OBJECTIVES: The understanding of antimicrobial utilization patterns is pertinent to successful implementation of the National Action Plans on Antimicrobial Resistance (AMR). There is, however, limited information on antibiotics utilization in Nigeria. This study was undertaken to build on existing information and provide direction for appropriate interventions including Antibiotics Stewardship Programs (ASP). METHOD: A Point Prevalence Study (PPS) was conducted in two public urban health facilities in Lagos, Nigeria using a design adapted from the European Center for Disease Prevention and Control (ECDC) and Global-PPS surveys. RESULTS: The prevalence of antibiotics use was 80.6% administered mostly parenterally (83.1% of total prescriptions) with concerns with extended surgical antibiotics prophylaxis. The mostly used antibiotics in the secondary hospital were parenteral metronidazole (32.4%), ceftriaxone (27.5%), and amoxicillin + clavulanate (8.2%) while the mostly used in the tertiary hospital were ceftriaxone (25.3%), parenteral metronidazole (19.1%), and amoxicillin + clavulanate (9.3%). There was an appreciable lack of specific functional capacities, policies, and processes to promote appropriate antimicrobial use in both hospitals. CONCLUSIONS: There is high rate of antibiotics utilization in these facilities with lack of institutional frameworks and processes for ensuring appropriate antibiotic use. The study provides the information needed to improve future antimicrobial use in hospitals and reduce AMR.

Improving the Understanding of the Immunopathogenesis of Lymphopenia as a Correlate of SARS-CoV-2 Infection Risk and Disease Progression in African Patients: Protocol for a Cross-sectional Study.

BACKGROUND: The COVID-19 pandemic, caused by SARS-CoV-2, continues to impact health systems throughout the world with serious medical challenges being imposed on many African countries like Nigeria. Although emerging studies have identified lymphopenia as a driver of cytokine storm, disease progression, and poor outcomes in infected patients, its immunopathogenesis, as well as environmental and genetic determinants, remain unclear. Understanding the interplay of these determinants in the context of lymphopenia and COVID-19 complications in patients in Africa may help with risk stratification and appropriate deployment of targeted treatment regimens with repurposed drugs to improve prognosis. OBJECTIVE: This study is designed to investigate the role of vitamin D status, vasculopathy, apoptotic pathways, and vitamin D receptor (VDR) gene polymorphisms in the immunopathogenesis of lymphopenia among African people infected with SARS-CoV-2. METHODS: This cross-sectional study will enroll 230 participants, categorized as "SARS-CoV-2 negative" (n=69), "COVID-19 mild" (n=32), "hospitalized" (n=92), and "recovered" (n=37), from two health facilities in Lagos, Nigeria. Sociodemographic data, travel history, and information on comorbidities will be obtained from case files and through a pretested, interview-based structured questionnaire. Venous blood samples (5 mL) collected between 8 AM and 10 AM and aliquoted into EDTA (ethylenediaminetetraacetic acid) and plain tubes will be used for complete blood count and CD4 T cell assays to determine lymphopenia (lymphocyte count <1000 cells/µL) and CD4 T lymphocyte levels, as well as to measure the concentrations of vitamin D, caspase 3, soluble vascular cell adhesion molecule-1 (sVCAM-1), and soluble Fas ligand (sFasL) using an autoanalyzer, flow cytometry, and ELISA (enzyme-linked immunosorbent assay) techniques. Genomic DNA will be extracted from the buffy coat and used as a template for the amplification of apoptosis-related genes (Bax, Bcl-2, BCL2L12) by polymerase chain reaction (PCR) and genotyping of VDR (Apa1, Fok1, and Bsm1) gene polymorphisms by the PCR restriction fragment length polymorphism method and capillary sequencing. Total RNA will also be extracted, reverse transcribed, and subsequently quantitated by reverse transcription PCR (RT-PCR) to monitor the expression of apoptosis genes in the four participant categories. Data analyses, which include a test of association between VDR gene polymorphisms and study outcomes (lymphopenia and hypovitaminosis D prevalence, mild/moderate and severe infections) will be performed using the R statistical software. Hardy-Weinberg equilibrium and linkage disequilibrium analyses for the alleles, genotypes, and haplotypes of the genotyped VDR gene will also be carried out. RESULTS: A total of 45 participants comprising 37 SARS-CoV-2-negative and 8 COVID-19-recovered individuals have been enrolled so far. Their complete blood counts and CD4 T lymphocyte counts have been determined, and their serum samples and genomic DNA and RNA samples have been extracted and stored at -20 °C until further analyses. Other expected outcomes include the prevalence and distribution of lymphopenia and hypovitaminosis D in the control (SARS-CoV-2 negative), confirmed, hospitalized, and recovered SARS-CoV-2-positive participants; association of lymphopenia with CD4 T lymphocyte level, serum vitamin D, sVCAM-1, sFasL, and caspase 3 levels in hospitalized patients with COVID-19; expression levels of apoptosis-related genes among hospitalized participants with COVID-19, and those with lymphopenia compared to those without lymphopenia; and frequency distribution of the alleles, genotypes, and haplotypes of VDR gene polymorphisms in COVID-19-infected participants. CONCLUSIONS: This study will aid in the genotypic and phenotypic stratification of COVID-19-infected patients in Nigeria with and without lymphopenia to enable biomarker discovery and pave the way for the appropriate and timely deployment of patient-centered treatments to improve prognosis. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/21242.

Key Issues Surrounding Appropriate Antibiotic Use for Prevention of Surgical Site Infections in Low- and Middle-Income Countries: A Narrative Review and the Implications.

BACKGROUND: There is a concern with the growing use of antimicrobials across countries increasing antimicrobial resistance (AMR) rates. A key area within hospitals is their use for the prevention of surgical site infections (SSI) with concerns with timing of the first dose, which can appreciably impact on effectiveness, as well as duration with extended prophylaxis common among low- and middle-income countries (LMICs). This is a concern as extended duration increases utilization rates and AMR as well as adverse events. Consequently, there is a need to document issues of timing and duration of surgical antibiotic prophylaxis (SAP) among LMICs together with potential ways forward to address current concerns. METHODS: Narrative review of timings and duration of SAP among LMICs combined with publications documenting successful approaches to improve SAP to provide future direction to all key stakeholder groups. RESULTS: There were documented concerns with the timing of the first dose of antibiotics, with appropriate timing as low as 6.7% in Egypt, although as high as 81.9% in Turkey. There was also an extensive duration of SAP, ranging from long duration times in all patients in a study in Nigeria with a mean of 8.7 days and 97% of patients in Egypt to 42.9% of patients in Pakistan and 35% in Turkey. Successful interventions to improve SAP typically involved multiple approaches including education of all key stakeholder groups, monitoring of usage against agreed guidelines,as well as quality targets. Multiple approaches typically improved timing and duration as well as reduced costs. For instance, in one study appropriateness increased from 30.1% to 91.4%, prolonged duration reduced to 5.7% of patients, and mean costs of antibiotics decreased 11-fold. CONCLUSION: There are considerable concerns with the timing and duration of SAP among LMICs. Multiple interventions among LMICs can address this providing future directions.

Strategies to Improve Antimicrobial Utilization with a Special Focus on Developing Countries.

Antimicrobial resistance (AMR) is a high priority across countries as it increases morbidity, mortality and costs. Concerns with AMR have resulted in multiple initiatives internationally, nationally and regionally to enhance appropriate antibiotic utilization across sectors to reduce AMR, with the overuse of antibiotics exacerbated by the COVID-19 pandemic. Effectively tackling AMR is crucial for all countries. Principally a narrative review of ongoing activities across sectors was undertaken to improve antimicrobial use and address issues with vaccines including COVID-19. Point prevalence surveys have been successful in hospitals to identify areas for quality improvement programs, principally centering on antimicrobial stewardship programs. These include reducing prolonged antibiotic use to prevent surgical site infections. Multiple activities centering on education have been successful in reducing inappropriate prescribing and dispensing of antimicrobials in ambulatory care for essentially viral infections such as acute respiratory infections. It is imperative to develop new quality indicators for ambulatory care given current concerns, and instigate programs with clear public health messaging to reduce misinformation, essential for pandemics. Regular access to effective treatments is needed to reduce resistance to treatments for HIV, malaria and tuberculosis. Key stakeholder groups can instigate multiple initiatives to reduce AMR. These need to be followed up.

COVID-19 rapid diagnostic test could contain transmission in low- and middle-income countries.

BACKGROUND: Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has impacted heavily on global health. Although real-time polymerase chain reaction (RT-PCR) is the current diagnostic method, challenges for low- and middle-income countries (LMICs) necessitate cheaper, higher-throughput, reliable rapid diagnostic tests (RDTs). OBJECTIVE: We reviewed the documented performance characteristics of available COVID-19 RDTs to understand their public health utility in the ongoing pandemic, especially in resource-scarce LMIC settings. METHODS: Using a scoping review methodology framework, common literature databases and documentary reports were searched up to 22 April 2020, irrespective of geographical location. The search terms included 'SARS-CoV-2 AND serological testing' and 'COVID-19 AND serological testing'. RESULTS: A total of 18 RDTs produced in eight countries, namely China (6; 33.33%), the United States (4; 22.22%), Germany (2; 11.11%), Singapore (2; 11.11%), Canada, Kenya, Korea and Belgium (1 each; 5.56%), were evaluated. Reported sensitivity ranged from 18.4% to 100% (average = 84.7%), whereas specificity ranged from 90.6% to 100% (average = 95.6%). The testing time ranged from 2 min to 30 min. Of the 12 validated RDTs, the IgM/IgG duo kit with non-colloidal gold labelling system was reported to elicit the highest sensitivity (98% - 100%) and specificity (98% - 99% for IgG and 96% - 99% for IgM). CONCLUSION: We found reports of high sensitivity and specificity among the developed RDTs that could complement RT-PCR for the detection of SARS-CoV-2 antibodies, especially for screening in LMICs. However, it is necessary to validate these kits locally.

High proportion of carbapenemase-producing Escherichia coli and Klebsiella pneumoniae among extended-spectrum ß-lactamase-producers in Nigerian hospitals.

OBJECTIVES: Carbapenem-resistant Enterobacterales are a global problem, however little is known about the burden and origin of carbapenem resistance in Africa. The objectives of this study were to determine the proportion of carbapenem-resistant isolates among extended-spectrum ß-lactamase-producing Enterobacterales (ESBL-E), to identify the underlying mechanisms of resistance and to assess the population structure of carbapenem-resistant isolates from Nigeria. METHODS: ESBL-E isolates (n = 175) from infections were collected at four hospitals in Lagos, Nigeria, from July 2016 to January 2018 and were screened for carbapenem resistance using a VITEK®2 automated system. All carbapenem-resistant ESBL-E (CRE) were screened for blaKPC, blaCTX-M, blaCMY-2, blaNDM, blaVIM, blaIMP, blaOXA-181 and blaOXA-48 genes. Genotyping of randomly selected isolates was performed by whole-genome sequencing. RESULTS: The isolates included Escherichia coli (n = 113; 64.6%) and Klebsiella pneumoniae (n = 62; 35.4%). Of the 175 ESBL-E isolates, 48 (27.4%) were resistant to carbapenems (15 E. coli and 33 K. pneumoniae). CRE isolates carried blaNDM (n = 30; 62.5%), blaNDM + blaOXA-181 (n = 10; 20.8%), blaOXA-181 (n = 2; 4.2%) and blaNDM + blaOXA-48 (n = 1; 2.1%); no carbapenemase gene was detected in 5 isolates (10.4%). The isolates showed low diversity and were mainly associated with multilocus sequence typing (MLST) sequence types ST410 for E. coli and ST395 and ST147 for K. pneumoniae. CONCLUSION: Carbapenem resistance is frequent among ESBL-E in Nigeria and is mainly associated with blaNDM. Genotyping suggested that the observed clones possibly originated from Southeast Asia.

Case Report on Pleural Empyema Thoracis and Urinary Tract Infection Caused by Chromobacterium violaceum from Lagos, Nigeria.

Chromobacterium violaceum has been implicated as an important cause of invasive diseases such as septicaemia in neonates and immune-compromised adults with high risk of misdiagnosis, mistreatment, and poor outcomes. Here, we report three new cases of C. violaceum infections in three different hospitalised patients with empyema thoracis (one case) and urinary tract infections (two cases) in a tertiary Hospital in Lagos, Nigeria, and the diagnosis was confirmed with the MALDI-TOF MS instrument. The patients were admitted and treated with parenteral antibiotics (ciprofloxacin, cefotaxime, and ceftriaxone) and discharged after clinical cure. Clinical and Laboratory findings from this study revealed C. violaceum as an emerging and an "underdiagnosed" pathogen causing human infections in Nigeria with ciprofloxacin identified as an effective empirical treatment. Follow-up of cases treated with microbiologically efficacious antibiotics indicates a good treatment outcome.

Persistent Staphylococcus aureus nasal colonization in ambulatory human immunodeficiency virus-infected patients in Nigeria: Risk factors and molecular features.

This longitudinal study on Staphylococcus aureus colonization in Nigerian human immunodeficiency virus patients (n = 187) found a trend towards a higher proportion of persistent S. aureus carriage in patients with advanced human immunodeficiency virus infection, low CD4+ cell counts, and a predominance of isolates belonging to ST8/spa-CC064 in persistent carriers.

Clonal expansion accounts for an excess of antimicrobial resistance in Staphylococcus aureus colonising HIV-positive individuals in Lagos, Nigeria.

Nasal colonisation with Staphylococcus aureus is a risk factor for invasive infection in human immunodeficiency virus (HIV)-positive individuals. This study aimed to characterise colonising S. aureus from regions with a high HIV prevalence. Single nasal swabs were taken from a total of 374 HIV-positive and 370 healthy individuals. Overall, 202 S. aureus carriers were detected. Compared with healthy individuals, HIV-positive subjects were more likely to be S. aureus nasal carriers (33% vs. 21%; P=0.0001). Isolates from HIV-positive individuals were more often resistant to meticillin (16% vs. 8%; P=0.13), chloramphenicol (47% vs. 16%; P<0.0001), sulfamethoxazole/trimethoprim (SXT) (90% vs. 55%; P<0.0001) and ciprofloxacin (18% vs. 0%; P<0.0001). Strains belonging to the spa clonal complexes 3772/ST25 and 064/ST8 were significantly more often isolated from HIV-positive individuals and exhibited greater resistance to ciprofloxacin, SXT and chloramphenicol (spa-CC 3772) or to meticillin (spa-CC 064), respectively. Panton-Valentine leukocidin gene content was high overall and was equally distributed between isolates from HIV-positive and healthy individuals (33% vs. 30%). Genotypic characteristics of colonising isolates were similar to those reported to cause invasive infection in Nigeria. The HIV pandemic contributes to the evolution of antimicrobial resistance in S. aureus. Measures to contain antimicrobial resistance of S. aureus in Nigeria must target risk groups such as HIV-positive individuals.