Dissemination of the Transmissible Quinolone-Resistance Gene qnrS1 by IncX Plasmids in Nigeria

The plasmid-encoded quinolone resistance gene qnrS1 was recently found to be commonly associated with ciprofloxacin resistance in Nigeria. We mapped the qnrS1 gene from an Escherichia coli isolate obtained in Nigeria to a 43.5 Kb IncX2 plasmid. The plasmid, pEBG1, was sufficient to confer ciprofloxacin non-susceptibility, as well as tetracycline and trimethoprim resistance, on E. coli K-12. Deletion analysis confirmed that qnrS1 accounted for all the ciprofloxacin non-suceptibility conferred by pEBG1 and tetracycline and trimethoprim resistance could be attributed to tetAR and dfrA14 genes respectively. While it contained a complete IncX conjugation system, pEBG1 was not self-transmissible likely due to an IS3 element inserted between the pilX5 and pilX6 genes. The plasmid was however efficiently mobilizable. pEBG1 was most similar to another qnrS1-bearing IncX2 plasmid from Nigeria, but both plasmids acquired qnrS1 independently and differ in their content of other resistance genes. Screening qnrS1-positive isolates from other individuals in Nigeria revealed that they carried neither pEBG1 nor pNGX2-QnrS1 but that IncX plasmids were prevalent. This study demonstrates that the IncX backbone is a flexible platform that has contributed to qnrS1 dissemination in Nigeria

INTESTINAL PARASITES, NUTRITIONAL STATUS AND COGNITIVE FUNCTION AMONG PRIMARY SCHOOL PUPILS IN ILE-IFE, OSUN STATE, NIGERIA

Background: Intestinal parasites are a cause of morbidity and mortality throughout the world particularly in developing countries and they are common health problems of children. This study determined the prevalence of intestinal parasites among primary school children, assessed risk factors predisposing to infection and the nutritional status with cognitive function of the pupils. Materials and Methods: It was a cross sectional study and 384 pupils from six public primary schools in Ile-Ife were enrolled. Anthropometric measurements were obtained using standard procedures. The intelligence quotients of the pupils were assessed using the Draw-a-person- test. Stool samples were collected and examined. Data was processed using SPSS Inc USA version 17. Statistical analysis was done using frequency, percentages, tables and Pearson’s chisquare was used to determine the association between intestinal parasites, nutritional status and cognitive function. Results: The prevalence of intestinal parasites in the study population was 24% with double infection occurring in 3.2%. Ascaris lumbricoides most prevalent 22.1%, Hookworm 3.4%, Hymenolepis nana 0.3%. Intestinal parasites were present in those that use bush and refuse dump for defeacation. The nutritional status of the pupils showed 95.8% normal weight, 3.6% underweight and 0.5% overweight. In terms of cognition, 65.4% mentally deficient, 14.3% mentally dull and 20.3% average. Conclusion: Intestinal parasites were prevalent among primary school children and use of bush or refuse dump for defeacation was a risk factor. There was no association between intestinal parasites, nutritional status and cognition

Regional Dissemination of a Trimethoprim-Resistance Gene Cassette via a Successful Transposable Element

Antimicrobial resistance is a growing international problem. We observed a 50% increase in the prevalence of trimethoprim resistance among fecal Escherichia coli from healthy Nigerian students between 1998 and 2005, a trend to increase that continued in 2009.A PCR-based screen revealed that 131 (43.1%) of isolates obtained in Nigeria in 2005 and 2009 carried integron-borne dfrA cassettes. In the case of 67 (51.1%) of these isolates, the cassette was a class 1-integron-borne dfrA7 gene, which has been reported at high prevalence from E. coli isolates from other parts of Africa. Complete sequencing of a 27 Kb dfrA7-bearing plasmid from one isolate located the dfrA7 gene within a Tn21-type transposon. The transposon also contained an IS26-derived bla/sul/str element, encoding resistance to β-lactams, sulphonamides and streptomycin, and mercury resistance genes. Although the plasmid backbone was only found in 12 (5.8%) of trimethoprim-resistant isolates, dfrA7 and other transposon-borne genes were detected in 14 (16.3%) and 32 (26.3%) of trimethoprim resistant isolates collected in Nigeria in 2005 and 2009, respectively. Additionally, 37 (19.3%) of trimethoprim-resistant E. coli isolates collected between 2006 and 2008 from Ghana were positive for the dfrA7 and a transposon marker, but only 4 (2.1%) harbored the plasmid backbone.Our data point to transposition as a principal mechanism for disseminating dfrA7 among E. coli from Nigeria and Ghana. On-going intensive use of the affordable broad-spectrum antibacterials is likely to promote selective success of a highly prevalent transposable element in West Africa

Factors associated with positive blood cultures in children in nine African and Asian countries : the ACORN2 surveillance network

Funding: This research was funded in whole by the Wellcome Trust [222156/Z/20/Z]. CAG was funded by a Postdoctoral Mobility Fellowship from the Swiss National Science Foundation (grant number P500PM_217605).Background Blood culture (BC) in children has relatively low diagnostic yield and high contamination rates, limiting cost-effectiveness. We aimed to determine readily available baseline characteristics to identify hospitalised children with a likelihood of higher diagnostic yield in low- and middle-income countries. Methods We used data from ACORN2, a prospective clinical surveillance network including 19 hospitals across Africa and Asia. We included participants <18 years, hospitalised for a suspected infection, prescribed parenteral antibiotics and with a BC sample. Sociodemographic and clinical data were recorded for each infection episode and linked to routine microbiology data. We described true pathogen (non-contaminant) BC positivity proportion and performed mixed-effects logistic regression, with study site and patient as the random effect, to identify factors associated with BC positivity. Results Of the 26 407 paediatric infection episodes, 17 815 (67%) had a BC sample and 15 384 were included in the analysis. BC results were: true pathogens in 689 (4.5%), contaminants in 1399 (9%) and uncertain pathogens in 143 (0.9%). In the multivariable model, factors associated with a positive BC were age (29 days–12-month-olds OR 1.33, 95% CI 1.06 to 1.66 and 5–18 year-olds OR 1.62, 95% CI 1.30 to 2.01 vs 1–4 year-olds), number of clinical severity signs (OR 1.29, 95% CI 1.18 to 1.40 per one sign) and hospital acquired infection (OR 3.05, 95% CI 2.30 to 4.06 vs community-acquired). Suspected diagnosis of sepsis (OR 2.09, 95% CI 1.67 to 2.61), gastrointestinal/abdominal (OR 2.36, 95% CI 1.78 to 3.13), skin and soft tissue or bone (OR 3.64, 95% CI 2.57 to 5.14) and genitourinary infection (OR 2.22, 95% CI 1.39 to 3.56) were more likely to have a positive BC, compared with respiratory infections. Conclusion We confirmed the low BC yield among hospitalised children. We identified groups for which diagnostic stewardship efforts to increase BC uptake should be prioritised and others in which it could be limited in times of financial or logistic constraints.Peer reviewe

High Level Plasmid-Mediated Quinolone Resistance in Clinical Infections at a Tertiary Healthcare Institution in South-West Nigeria

Abstract Background Plasmid-mediated quinolone resistance (PMQR) has become a growing clinical concern worldwide. Recent reports from Nigeria revealed that qunolone resistant clinical isolates have become commomplace. However, few reports regarding the prevalence of PMQR are available. Hence, this study aimed to determine the prevalence of PMQR genes in qunolone resistant clinical isolates from a tertiary care hospital in Nigeria. Methods This was a cross-sectional hospital based study involving 390 non-repetitive Gram negative bacilli from diverse clinical infections. The isolates were characterized by the MicrobactTM identification kit and their susceptibility patterns determined by the Kirby-Bauer disc diffusion technique. All quinolone resistant isolates were investigated for the carriage of PMQR genes by multiplex polymerase chain reaction (PCR). Data analysis was with appropriate descriptive and inferential statistics.Results The isolates were distributed as Escherichia coli (n=121; 31.0%), Klebsiella species (n= 112;28.7%), Pseudomonas aeruginosa (n=59;15.1%), Proteus species (n=43;11.0%), Salmonella species (n=6;1.3%) and others. They were commonly resistant to nalidixic (62.6%), co-amoxiclav (57.7%); norfloxacin (52.3%), ofloxacin(52.1%) and ciprofloxacin(51.0%), but were least resistant to imipenem; (n=36; 9.2%). Out of 244 isolates that were resistant to at least one quinolone, 180 (73.8%) harboured one or more PMQR gene with a high prevalence of efflux-mediating determinants (qepA, 22.5%; oqxAB, 21.1%), and the aminoglycoside acetyltransferase (aac(6’)-Ib-cr, 19.7%). Proportionately low level of target-protecting determinants; qnrB, 13.2%; qnrS, 8.7%; qnrA, 5.9%; qnrD, 4.5% and qnrC, 4.2% were found in these isolates.Conclusion There is high level quinolone resistance and wide distribution of PMQR genes in clinical isolates in Nigeria with a preponderance of Efflux-mediating determinants and the aminoglycoside acetyltransferase. This emphasizes the need for regular resistance surveillance and antimicrobial stewardship to guide the appropriate and judicious use of antibiotics.</jats:p

High Level Plasmid-Mediated Quinolone Resistance in Clinical Infections at a Tertiary Healthcare Institution in South-West Nigeria

Abstract Background Plasmid-mediated quinolone resistance (PMQR) has become a growing clinical concern worldwide. Recent reports from Nigeria revealed that qunolone resistant clinical isolates have become commomplace. However, few reports regarding the prevalence of PMQR are available. Hence, this study aimed to determine the prevalence of PMQR genes in qunolone resistant clinical isolates from a tertiary care hospital in Nigeria. Methods This was a cross-sectional hospital based study involving 390 non-repetitive Gram negative bacilli from diverse clinical infections. The isolates were characterized by the MicrobactTM identification kit and their susceptibility patterns determined by the Kirby-Bauer disc diffusion technique. All quinolone resistant isolates were investigated for the carriage of PMQR genes by multiplex polymerase chain reaction (PCR). Data analysis was with appropriate descriptive and inferential statistics.Results The isolates were distributed as Escherichia coli (n=121; 31.0%), Klebsiella species (n= 112;28.7%), Pseudomonas aeruginosa (n=59;15.1%), Proteus species (n=43;11.0%), Salmonella species (n=6;1.3%) and others. They were commonly resistant to nalidixic (62.6%), co-amoxiclav (57.7%); norfloxacin (52.3%), ofloxacin(52.1%) and ciprofloxacin(51.0%), but were least resistant to imipenem; (n=36; 9.2%). Out of 244 isolates that were resistant to at least one quinolone, 180 (73.8%) harboured one or more PMQR gene with a high prevalence of efflux-mediating determinants (qepA, 22.5%; oqxAB, 21.1%), and the aminoglycoside acetyltransferase (aac(6’)-Ib-cr, 19.7%). Proportionately low level of target-protecting determinants; qnrB, 13.2%; qnrS, 8.7%; qnrA, 5.9%; qnrD, 4.5% and qnrC, 4.2% were found in these isolates.Conclusion There is high level quinolone resistance and wide distribution of PMQR genes in clinical isolates in Nigeria with a preponderance of Efflux-mediating determinants and the aminoglycoside acetyltransferase. This emphasizes the need for regular resistance surveillance and antimicrobial stewardship to guide the appropriate and judicious use of antibiotics.</jats:p

Multicenter Study of the Burden of Multidrug-Resistant Bacteria in the Etiology of Infected Diabetic Foot Ulcers

AbstractBackgroundInfected diabetic foot ulcer (IDFU) is a public health issue and a leading cause of non-traumatic limb amputation. Very few published data on IDFU is available in most West African countries. The objective of this study was to investigate the etiological agents of IDFU and the challenge of antibacterial drug resistance in the management of infections.MethodsThis was a prospective cross-sectional hospital-based study involving three tertiary healthcare facilities. Consecutive eligible patients presenting in the facilities were recruited. Tissue biopsies and/or aspirates were collected and cultured on a set of selective and non-selective media and incubated in appropriate atmospheric conditions for 24 to 72 hours. Isolates were identified by established standard methods. Antibiotic susceptibility testing was performed using modified Kirby-Bauer disc diffusion method. Specific resistance determinants were investigated by polymerase chain reaction-based protocols. Data analysis was done with SPSS version 20.ResultsNinety patients with clinical diagnosis of DFI were studied between July 2016 and April 2017. A total of 218 microorganisms were isolated, comprising 129 (59.2%) Gram-negative bacilli (GNB), 59 (27.1%) Gram-positive cocci (GPC) and 29 (13.2%) anaerobic bacteria. The top five facultative/aerobic bacteria encountered were: Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae and Citrobacter spp. representing 41 (18.8%), 23 (10.5%), 20 (9.2%), 19 (8.7%) and 19 (8.7%) isolates, in that order, respectively. The commonest anaerobes were Bacteroides spp., and Peptostreptococcus anaerobius which accounted for 7 (24.1%) and 6 (20.7%), respectively. Of the 93 IDFU cases, 74 (80%) were infected by multidrug-resistant (MDR) bacteria predominantly methicillin-resistant S. aureus, extended-spectrum β-lactamase-producing GNB, mainly of the CTX-M variety. Only 4 (3.1%) GNB were carbapenemase-producers encoded by blaVIM. Factors associated with presence of MDR bacteria were peripheral neuropathy (r= 4.05, P= 0.042) and duration of foot infection &gt;1 month(r= 7.63, P= 0.015).ConclusionsMDR facultative/aerobic bacteria are overrepresented amongst agents causing IDFU. A relatively low proportion of the etiological agents were anaerobic bacteria. This finding should help formulate empirical therapeutic options for managing IDFU. Furthermore, drastic reduction in inappropriate use of cocktail of antibiotics for IDFUs is advocated to combat infection by MDR bacteria in these patients.</jats:sec