Extended-spectrum Beta-lactamases Encoding Genes among Salmonella Enterica serovar Typhi Isolates in Patients with Typhoid Fever from four Academic Medical Centers Lagos, Nigeria.

BACKGROUND: There is scarce information about the occurrence of extended-spectrum ß-lactamases (ESBLs) in Salmonella enterica serovar Typhi (S. Typhi) from patients with typhoid fever. OBJECTIVE: To study the antimicrobial resistance and ESBL encoding genes among S. Typhi isolates in aforesaid patients from Lagos, Nigeria. METHODS: S. Typhi isolates were collected from blood samples of typhoid fever patients from 4 academic medical centers in Lagos, Nigeria. The identification of isolates and their antibiotic susceptibility testing were performed by standard bacteriological techniques and disc diffusion method, respectively. The production of ESBLs was investigated using combination disk test (CDT) and polymerase chain reaction (PCR). RESULTS: A total of 27 S. Typhi isolates was collected. All isolates were susceptible to imipenem and nitrofurantoin. Fifteen (55.6%) isolates were multidrug-resistant (MDR). The CDT test showed 11 (40.7%) ESBL producer isolates. However, the PCR revealed a higher occurrence rate for ESBL producers (66.7%, n = 18/27). The ESBL genes were as follows: blaCTX-M (37.0%, n = 10/27), blaSHV (18.5%, n = 5/27), and blaTEM (44.4%, n = 12/27). All ESBL positive S. Typhi isolates were MDR. CONCLUSIONS: This study showed the emergence of ESBL-harboring S. Typhi in patients with typhoid fever from Nigeria.

Genetic polymorphisms in malaria vaccine candidate Plasmodium falciparum reticulocyte-binding protein homologue-5 among populations in Lagos, Nigeria.

BACKGROUND: Vaccines are the most reliable alternative to elicit sterile immunity against malaria but their development has been hindered by polymorphisms and strain-specificity in previously studied antigens. New vaccine candidates are therefore urgently needed. Highly conserved Plasmodium falciparum reticulocyte-binding protein homologue-5 (PfRH5) has been identified as a potential candidate for anti-disease vaccine development. PfRH5 is essential for erythrocyte invasion by merozoites and crucial for parasite survival. However, there is paucity of data on the extent of genetic variations on PfRH5 in field isolates of Plasmodium falciparum. This study described genetic polymorphisms at the high affinity binding polypeptides (HABPs) 36718, 36727, 36728 of PfRH5 in Nigerian isolates of P. falciparum. This study tested the hypothesis that only specific conserved B and T cell epitopes on PfRH5 HABPs are crucial for vaccine development. METHODS: One hundred and ninety-five microscopically confirmed P. falciparum samples collected in a prospective cross-sectional study of three different populations in Lagos, Nigeria. Genetic diversity and haplotype construct of Pfrh5 gene were determined using bi-directional sequencing approach. Tajima's D and the ratio of nonsynonymous vs synonymous mutations were utilized to estimate the extent of balancing and directional selection in the pfrh5 gene. RESULTS: Sequence analysis revealed three haplotypes of PfRH5 with negative Tajima's D and dN/dS value of - 1.717 and 0.011 ± 0.020, respectively. A single nucleotide polymorphism, SNP (G → A) at position 608 was observed, which resulted in a change of the amino acid cysteine at position 203 to tyrosine. Haplotype and nucleotide diversities were 0.318 ± 0.016 and 0.0046 ± 0.0001 while inter-population genetic differentiation ranged from 0.007 to 0.037. Five polypeptide variants were identified, the most frequent being KTKYH with a frequency of 51.3%. One B-cell epitope, 151 major histocompatibility complex (MHC) class II T-cell epitopes, four intrinsically unstructured regions (IURs) and six MHC class I T-cell epitopes were observed in the study. Phylogenetic analysis of the sequences showed clustering and evidence of evolutionary relationship with 3D7, PAS-2 and FCB-2 RH5 sequences. CONCLUSIONS: This study has revealed low level of genetic polymorphisms in PfRH5 antigen with B- and T-cell epitopes in intrinsically unstructured regions along the PfRH5 gene in Lagos, Nigeria. A broader investigation is however required in other parts of the country to support the possible inclusion of PfRH5 in a cross-protective multi-component vaccine.

Genome Analysis of Multidrug-Resistant Escherichia coli Isolated from Poultry in Nigeria.

Escherichia coli is one of the most common commensal bacteria of the gastrointestinal tract of humans and warm-blooded animals. Contaminated poultry can lead to disease outbreaks in consumers causing massive economic losses in the poultry industry. Additionally, commensal E. coli can harbor antibiotic resistance genes that can be transferred to other bacteria, including pathogens, in a colonized human host. In a previous study on antimicrobial resistance of E. coli from food animals from Nigeria, multidrug-resistant E. coli were detected. Three of those isolates were selected for further study using whole-genome sequencing due to the extensive drug resistance exhibited. All of the isolates carried the extended-spectrum ß-lactamase (ESBL) genes, blaCTX-M15 and blaTEM-1, whereas one isolate harbored an additional ESBL, blaOXA-1. All of the tetracycline-resistant isolates carried tet(A). The genes aac3-IIa and aacA4, conferring resistance to aminoglycosides, were identified in an E. coli isolate resistant to gentamicin and tobramycin. In two E. coli isolates, dfrA14, qnrS1, and sulII, were detected conferring resistance to trimethoprim, fluoroquinolones, and sulfonamides, respectively. The third isolate carried dfrA17, no fluoroquinolone resistance gene, an additional sulI gene, and a chloramphenicol resistance gene, catB3. Mutations in candidate genes conferring resistance to fosfomycin and fluoroquinolones were also detected. Several efflux systems were detected in all the E. coli isolates and virulence-associated genes related to serum resistance, motility, and adhesion. E. coli and non-E. coli origin prophages were also identified in the isolates. The results underline the higher resolution power of whole-genome sequencing for investigation of antimicrobial resistance, virulence, and phage in E. coli.

Characterization of Vibrio cholerae Strains Isolated from the Nigerian Cholera Outbreak in 2010.

We examined clinical samples from Nigerian patients with acute watery diarrhea for Vibrio cholerae during the 2010 cholera outbreak. A total of 109 suspected isolates were characterized, but only 57 V. cholerae strains could be confirmed using multiplex real-time PCR as well as rpoB sequencing and typed as V. cholerae O:1 Ogawa biotype El Tor. This finding highlighted the need for accurate diagnosis of cholera in epidemic countries to implement life-saving interventions.

Genotyping by randomly amplified polymorphic DNA of bacteriocin producing Lactobacillus acidophilus strains from Nigeria.

Yogurt and starter culture producers are still searching strains of Lactobacillus acidophilus to produce healthier yogurt with a longer shelf life and better texture, taste, and quality. This study determined the genotyping of bacteriocin producing Lactobacillus acidophilus strains recovered from Nigerian yogurts. Yogurt samples were collected from four different states of South West regions of Nigeria. Isolates were obtained from MRS Medium and biochemically characterized. This was further confirmed by API50CH. The bacteriocin positivity and activity was determined. Genomic characterization of our Lactobacillus acidophilus strains was done with randomly amplified polymorphic DNA-PCR. All yogurt samples containing Lactobacillus acidophilus strains meet the probiotic requirement of ≥10(6) cfu/mL. The gel picture revealed 6 RAPD clonal types of Lactobacillus acidophilus strains with RAPD type C observed to be more common. Significant differences existed in the mean growth inhibition zone (t = -7.32, P < 0.05 for E. coli ATCC; t = -6.19, P < 0.05 for E. coli clinical isolates; t = -6.16, P < 0.05 for Enterobacter sp; t = -11.92, P < 0.05 for Salmonella typhi, t = -1.10, P > 0.05 Staphylococcus aureus). No correlation between the bacteriocin production, activity, and their RAPD clonal division (X(2) = 7.49, P = 0.1610, df = 5). In conclusion, L. acidophilus isolated in Nigeria samples met the probiotic requirements of ≥10(6) cfu/mL and produce bacteriocins with good spectrum of activity.

Whole genome sequencing and phylogenetic analysis of SARS-CoV-2 strains isolated during the COVID-19 pandemic in Nigeria.

Objectives: The emergence and spread of SARS-CoV-2 have stimulated ongoing research into the virus transmission dynamics, circulating variants, and potential mutations. This study was conducted to understand the genomic dynamics of the epidemic in Nigeria. Design: Whole genome sequencing was conducted on SARS-CoV-2 samples collected during the first and second outbreaks using the Oxford Nanopore MinION sequencing platform. Phylogenetic analysis was conducted, and genomes were grouped into different pangolin lineages. Results: The study revealed four circulating SARS-CoV-2 variants. The Alpha (B.1.1.7) variant was the most prevalent (32.7%), followed by Beta (B.1 B.1.1, L.3, and B.1.1.318) (30.8%), Eta (B.1.525) (28.9%), and Delta (B.1.617, AY.1, AY.109, and AY.36) (7.7%). Phylogenetic analysis revealed three clusters with four Nextstrain clades (20I, 20B, 21D, and 21J). The Alpha lineages (B.1.1.7) clustered with references from Italy. The Beta lineages (Clade 20B) (B.11, B.11318, and L3) and sub-lineage B.11 were distinct. Sub-lineage B.11318 is clustered with references from the USA, whereas sub-lineage L3 is clustered with references from Russia, the Philippines, Australia, and Japan. The 21D and 21J, belonging to two Pango lineages, Eta (B.1525) and Delta (B.1.617 and AY.109), showed high genetic similarity. Conclusion: The phylogenetic relatedness of the lineages suggests multiple virus introduction, which could be a source of more virulent, locally adapted variants.

16S rRNA metagenomics data on the bacterial communities in integrated poultry-fish farm ponds.

In an integrated poultry-fish (IPF) farming system, fish and bird are reared simultaneously. It is a common practice in Sub-Saharan Africa countries like Nigeria, Cameroon, Madagascar, and Benin, offering economic benefits to farmers and minimizing farm running costs. It seems like another way for farmers to manage poultry waste as it is a common practice in IPF farm settings to feed reared fishes with wastes emanating from the poultry. This work provides dataset on the bacterial taxonomic profile and abundance in IPF farm pond water samples using the 16S rRNA sequencing approach. Using ZymoBIOMICS®-96 MagBead DNA Kit, total DNA was extracted from pond water samples collected from IPF farm located at Ila-Orangun, Osun State, Southwest Nigeria (Long: 8° 1' N; Lat: 4° 54' E) during two sampling visits. The V3-V4 region of the rRNA gene was amplified and sequenced on the Miseq Illumina sequencing platform. Raw reads obtained after demultiplexing were analyzed using DADA2 pipeline to obtain distinctive or unique amplicon sequence variants which were grouped into Operational Taxonomic Units (OTUs) based on similarities. Taxonomy assignment was performed using UCLUST and Bayesian classifier from QIIME v.1.9.1 with the Zymo Research Database as reference. The phyla Proteobacteria (26.7%), Actinobacteria (26.0%), Firmicutes (13.1%), and Cyanobacteria (10.1%) dominated the 35 phyla obtained from the OTUs. Interestingly, the abundance of bacterial pathogens commonly associated with human infections was low. The sequence and sample data have been deposited in NCBI database under Sequence Read Archive (SRA) with Bioproject identification number PRJNA760919 (Accession number: SRX12020336 - SRX12020346). The dataset obtained can bridge the gap of limited information on the impact of IPF farming on pond bacterial diversity, a critical factor for considerations as regards food safety, fish, and public health.

Serum levels of leptin in Nigerian patients with sickle cell anaemia.

BACKGROUND: Several studies have shown that the pathophysiology of homozygous sickle cell anaemia (SCA) results in a myriad of metabolic, nutritional, haematological and clinical effects that interact with other co-morbid factors to determine the quality of life and life expectancy of afflicted patients. Because of its critical roles in nutrition and metabolism, inflammation, haematopoiesis and cellular immunity, this study determined the plasma levels of leptin in steady and unsteady states of HbSS in Nigerian patients. METHODS: A total of 51 SCA patients aged 5 - 35 years with 34 (61.8%) being females who were either on admission or visiting four medical centres in Lagos, Nigeria together with 22 non-SCD controls aged 5 -30 years comprising 12 (54.5%) females were enrolled after obtaining their informed consent and ethical approval. Patients were further stratified into steady and unsteady cases of SCA based on clinical presentations, while blood samples collected by venipuncture from each of the study participants were analyzed haematologically for full blood count and HbF level and microscopically for malaria, while plasma leptin was assayed using ELISA method. Body composition defined by weight, fat mass and body mass index (BMI) was determined using standard methods. Data obtained for cases and controls were analyzed statistically. RESULTS: Twenty - one patients had unsteady HbSS and elicited greater and significant (P < 0.05) reduction in fat mass, BMI, HbF and eosinophil count but elevated mean total leukocyte, count, level of irreversibly sickled cells and P. falciparum parasitaemia (4613.7 vs. 749.6 - 1078.4 parasites/uL), pyrexia rate (58.3 vs. 25.8%) when compared with steady state patients or non-SCD controls. Compared to the control, significant decreases in plasma leptin before and after controlling for body fat that was worsened by crisis were observed among the SCD patients. Unlike the non-SCD controls, leptin correlated non-significantly (P > 0.05) with all body composition indices measured in the patients except for fat mass in unsteady cases. Multivariate regression analysis identified ESR and RC as independent predictor of low plasma leptin concentration in the SCA patients. CONCLUSIONS: Base on these findings, we conclude that plasma level of leptin is further decreased in the unsteady state of HbSS, shows poor correlation with adiposity and malarial infection but has inflammation and poor reticulocyte response as independent predictors among Nigerian patients.

Evaluation of oxidative markers in women with invasive cervical cancer in Lagos, Nigeria.

Epidemiological studies have showed that low levels of antioxidants induce the generation of free radicals leading to DNA damage and further mutations seen in cancer. This study evaluated the effects of oxidative markers on the occurrence and severity of cervical cancer at the Lagos University Teaching Hospital. This was an analytical cross-sectional study carried out among women with histological diagnosis of invasive cervical cancer and their healthy cancer-free comparison group. Venous blood samples were collected from each participant for measurements of antioxidants (erythrocyte glutathione and vitamin C) and malondialdehyde (a marker of lipid peroxidation). Descriptive statistics were carried out for relevant demographic and clinical data. Associations between continuous variables were tested using the independent sample t-test or the analysis of variance for normally distributed data or the Mann-Whitney U test for skewed data, whereas categorical variables were compared using the χ2 test. p < 0.05 was considered statistically significant. The mean level of malondialdehyde (MDA) was statistically higher in women with cervical cancer than in their cancer-free counterparts (p = 0.032). However, the mean glutathione (32.6 ± 6.2 versus 14.2 ± 6.1 mg/dL; p = 0.019) and vitamin C (12.4 ± 2.3 versus 14.6 ± 2.4 µmol/L; p = 0.001) levels were significantly lower in the case group compared to the cancer-free group. There are statistically increasing mean levels of MDA (p = 0.017) and decreasing mean levels of vitamin C (p = 0.004) with increasing stages of the disease. This study showed that women with cervical cancer have low levels of antioxidants and an increased level of the oxidative marker. The levels of these markers become more pronounced as the disease progresses. This will, therefore, form the basis for the conduct of future randomised controlled trials of antioxidant supplementations among cervical cancer patients in sub-Saharan Africa.

The Emergence of Klebsiella pneumoniae with Reduced Susceptibility Against Third Generation Cephalosporins and Carbapenems in Lagos Hospitals, Nigeria.

This study investigated the prevalence of Klebsiella (K.) pneumoniae isolates among clinical samples of patients in four medical centers in Lagos, Nigeria and the burden of extended-spectrum beta-lactamases (ESBL) and carbapenem-resistant K. pneumoniae (CRKP) strains. Different samples (stool, blood, urine, wound swabs and nasal swabs) from 127 patients with suspected Gram-negative infections based on on-site performed Gram-stain from four public hospitals between March and September 2015 were analyzed. K. pneumoniae was identified in 43 (34%) patients. Resistance rates of these 43 strains according to the CLSI breakpoints were as followed: cotrimoxazole (90.7%), cefuroxime (74.4%), ofloxacin (55.8%), ceftazidime (46.5%), and cefixime (35%). Three isolates (7%) were resistant to imipenem. All isolates were susceptible to amoxicillin/clavulanic acid and nitrofurantoin. The prevalence of ESBL-producing, MDR and CRKP strains was 69.8%, 62.8%, and 7.0%, respectively. Of the ESBL-producing isolates, two K. pneumoniae isolates obtained from urine harbored both blaSHV and blaCTX-M-1, and a third isolate from urine harbored only the blaCTX-M-1. This study revealed the emergence of CRKP isolates and blaCTX-M-1 and blaSHV co-harboring K. pneumoniae strains in Lagos hospitals. The emergence of CRKP strains is an early warning signal for carbapenem antibiotics' prudent use with concern for their efficacies.

Plasmid Replicons and ß-Lactamase-Encoding Genes of Multidrug-Resistant Escherichia coli Isolated from Humans and Food Animals in Lagos, Southwest Nigeria.

As resistance to the ß-lactam class of antibiotics has become a worldwide problem, multidrug-resistant (MDR) human (n = 243) and food animal (n = 211) isolates from Lagos, Nigeria were further tested to characterize ß-lactamase-encoding genes and plasmid replicons. Four ß-lactamase-encoding genes (blaCMY, blaCTX-M, blaOXA, and blaTEM) were detected using PCR-based replicon typing, 13 and 17 different replicons were identified using a subset of MDR E. coli from humans (n = 48) and animals (n = 96), respectively. Replicon types FIB and X2 were detected in equal numbers (2/48; 4.2% each) from human isolates, while type Y (16/96; 16.7%) was the most common type from animals. Only two replicon types, FIB and Y, were detected in both groups; all other types were confined to one group or the other, but not both. Using conjugation, replicon type Y, present in three donors, transferred in all three instances, whereas FIA transferred in 75% (3/4) of the matings. This study showed that ß-lactamase genes were prevalent in MDR E. coli from both humans and animals in Nigeria and also contained diverse plasmid replicons. As the replicon-associated genes were mobile, they are likely to continue disseminating among E. coli and facilitating transfer of associated ß-lactamase genes in this region.

Impact of training of mothers, drug shop attendants and voluntary health workers on effective diagnosis and treatment of malaria in Lagos, Nigeria.

BACKGROUND: The National Malaria Eradication Program and international agencies are keen on scaling up the use of malaria rapid diagnostic tests (mRDTs) and artemisinin-based combination therapies (ACTs) for effective diagnosis and treatment of the disease. However, poor diagnostic skills and inappropriate treatment are limiting the efforts. In Nigeria, a large proportion of infected patients self-diagnose and treat while many others seek care from informal drug attendants and voluntary health workers. AIMS: This study describes the impact of training voluntary health workers, drug shop attendants, and mothers on effective case detection and treatment of malaria in Lagos, Nigeria. METHODS: We trained mothers accessing antenatal care, drug shop attendants, and voluntary health workers selected from the three districts of Lagos, on the use of histidine-rich protein-2-based mRDTs and ACTs. Pre- and post-training assessments, focus group discussions (FGDs), and in-depth interviews (IDIs) were carried out. RESULTS: The knowledge, attitude, and skill of the participants to achieve the goal of "test, treat, and track" using mRDT and ACTs were low (11%-55%). There was a low awareness of other non-malaria fevers among mothers. Self-medication was widely practiced (31.3%). FGDs and IDIs revealed that health-care providers administered antimalarials without diagnosis. Training significantly improved participants' knowledge and expertise on the use of mRDTs and ACTs (P = 0.02). The participants' field performance on mRDT use was significantly correlated with their category (bivariate r = 0.51, P = 0.001). There was no statistically significant association between the participants' level of education or previous field experience and their field performance on mRDT (r = 0.12, P = 0.9; χ 2= 38, df = 2 and P = 0.49). CONCLUSION: These findings suggest that training of stakeholders in malaria control improves diagnosis and treatment of malaria. However, a broader scope of training in other settings may be required for an effective malaria control in Nigeria.

Association between erythrocyte Na+K+-ATPase activity and some blood lipids in type 1 diabetic patients from Lagos, Nigeria.

BACKGROUND: Altered levels of erythrocyte Na+K+-ATPase, atherogenic and anti-atherogenic lipid metabolites have been implicated in diabetic complications but their pattern of interactions remains poorly understood.This study evaluated this relationship in Nigerian patients with Type 1 diabetes mellitus. METHODS: A total of 34 consented Type 1 diabetic patients and age -matched 27 non-diabetic controls were enrolled. Fasting plasma levels of total cholesterol, triglycerides and HDL-cholesterol were determined spectrophotometrically and LDL-cholesterol estimated using Friedewald formula. Total protein content and Na+K+-ATPase activity were also determined spectrophotometrically from ghost erythrocyte membrane prepared by osmotic lysis. RESULTS: Results indicate significant (P < 0.05) reduction in Na+K+-ATPase activity in the Type 1 diabetic patients (0.38 +/- 0.08 vs. 0.59 +/- 0.07 microM Pi/mgprotein/h) compared to the control but with greater reduction in the diabetic subgroup with poor glycemic control (n = 20) and in whom cases of hypercholesterolemia (8.8%), hypertriglyceridemia (2.9%) and elevated LDL-cholesterol (5.9% each) were found. Correlation analyses further revealed significant (P < 0.05) inverse correlations [r = -(0.708-0.797] between all the atherogenic lipid metabolites measured and Na+K+-ATPase in this subgroup contrary to group with good glycemic control or non-diabetic subjects in which significant (P < 0.05) Na+K+-ATPase and HDL-C association were found (r = 0.427 - 0.489). The Na+K+-ATPase from the diabetic patients also exhibited increased sensitivity to digoxin and alterations in kinetic constants Vmax and Km determined by glycemic status of the patients. CONCLUSION: It can be concluded that poor glycemic control evokes greater reduction in erythrocyte Na+K+-ATPase activity and promote enzyme-blood atherogenic lipid relationships in Type 1 diabetic Nigerian patients.

Pro-inflammatory Cytokine Response and Genetic Diversity in Merozoite Surface Protein 2 of Plasmodium falciparum Isolates from Nigeria.

BACKGROUND: Polymorphisms in Plasmodium falciparum merozoite surface protein-2 (msp-2) and associated parasite genetic diversity which varies between malaria-endemic regions remain a limitation in malaria vaccine development. Pro-inflammatory cytokines are important in immunity against malaria, understanding the influence of genetic diversity on cytokine response is important for effective vaccine design. METHODS: P. falciparum isolates obtained from 300 Nigerians with uncomplicated falciparum malaria at Ijede General Hospital, Ijede (IJE), General Hospital Ajeromi, Ajeromi (AJE) and Saint Kizito Mission Hospital, Lekki, were genotyped by nested polymerase chain reaction of msp-2 block 3 while ELISA was used to determine the pro-inflammatory cytokine response to describe the genetic diversity of P. falciparum. RESULTS: Eighteen alleles were observed for msp-2 loci. Of the 195 isolates, 61 (31.0%) had only FC27-type alleles, 38 (19.7%) had only 3D7-type alleles, and 49.3% had multiple parasite lines with both alleles. Band sizes were 275-625 bp for FC27 and 150-425 bp for 3D7. Four alleles were observed from LEK, 2 (375-425 bp) and 2 (275-325 bp) of FC27-and 3D7-types, respectively; 12 alleles from AJE, 9 (275-625 bp) and 3 (325-425 bp) of FC27-types and 3D7-types, respectively; while IJE had a total of 12 alleles, 9 (275-625 bp) and 3 (325-425 bp) of FC27-types and 3D7-types, respectively. Mean multiplicity of infection (MOI) was 1.54. Heterozygosity (HE) ranged from 0.77 to 0.87 and was highest for IJE (0.87). Cytokine response was higher among <5 years and was significantly associated with MOI (P > 0.05) but with neither parasite density nor infection type. CONCLUSION: P. falciparum genetic diversity is extensive in Nigeria, protection via pro-inflammatory cytokines have little or no interplay with infection multiplicity.

Draft Genome Sequence Analysis of Multidrug-Resistant Escherichia coli Strains Isolated in 2013 from Humans and Chickens in Nigeria.

Here, we present the draft genome sequences of nine multidrug-resistant Escherichia coli strains isolated from humans (n = 6) and chicken carcasses (n = 3) from Lagos, Nigeria, in 2013. Multiple extended-spectrum ß-lactamase (ESBL) genes were identified in these isolates.

Extended-spectrum Beta-lactamases Encoding Genes among Salmonella Enterica serovar Typhi Isolates in Patients with Typhoid Fever from four Academic Medical Centers in Lagos, Nigeria

ABSTRACT Background: There is scarce information about the occurrence of extended-spectrum β-lactamases (ESBLs) in Salmonella enterica serovar Typhi (S. Typhi) from patients with typhoid fever. Objective: To study the antimicrobial resistance and ESBL encoding genes among S. Typhi isolates in aforesaid patients from Lagos, Nigeria. Methods: S. Typhi isolates were collected from blood samples of typhoid fever patients from 4 academic medical centers in Lagos, Nigeria. The identification of isolates and their antibiotic susceptibility testing were performed by standard bacteriological techniques and disc diffusion method, respectively. The production of ESBLs was investigated using combination disk test (CDT) and polymerase chain reaction (PCR). Results: A total of 27 S. Typhi isolates was collected. All isolates were susceptible to imipenem and nitrofurantoin. Fifteen (55.6%) isolates were multidrug-resistant (MDR). The CDT test showed 11 (40.7%) ESBL producer isolates. However, the PCR revealed a higher occurrence rate for ESBL producers (66.7%, n = 18/27). The ESBL genes were as follows: blaCTX-M (37.0%, n = 10/27), blaSHV (18.5%, n = 5/27), and blaTEM (44.4%, n = 12/27). All ESBL positive S. Typhi isolates were MDR. Conclusions: This study showed the emergence of ESBL-harboring S. Typhi in patients with typhoid fever from Nigeria.

Prevalence and multidrug resistance of Escherichia coli from community-acquired infections in Lagos, Nigeria.

INTRODUCTION: The emergence of multidrug resistance (MDR; resistance to ≥ 2 more antimicrobials) in Escherichia coli is of concern due to complications encountered in treatment. METHODOLOGY: In this study, prevalence, antimicrobial resistance, and genetic characteristics of MDR community isolates of E. coli from Lagos, Nigeria were determined. Urine and stool samples were obtained from outpatients attending Lagos State hospitals and from animal handlers in abattoirs, poultries, and open markets, from December 2012 to July 2013. RESULTS: Approximately 50% of urine (200/394) and 88% of stool samples (120/136) were positive for E. coli. Based upon ß-lactamase production, a subset of those isolates was selected for further study. Of the 22 antimicrobials tested, E. coli exhibited resistance to all antimicrobials except amikacin and piperacillin/tazobactam. The highest levels of resistance were to tetracycline (182/247; 73.7%), trimethoprim/sulfamethoxazole (152/247; 61.5%), and ampicillin (147/247; 59.1%). Resistance to the cephalosporins ranged from 1.6%-15% including the third- and fourth-generation cephalosporins, cefpodoxime (20/247; 8.1%) and cefepime (4/247; 1.6%), respectively. MDR was observed in 69.6% (172/247) of the isolates. Forty-eight E. coli resistant to at least five antimicrobials were selected for further analysis using pulsed-field gel electrophoresis; seven distinct clusters were observed among the diverse patterns. Of the 48 MDR E. coli, 30 different sequence types (ST) were detected using multilocus sequence typing, including four ST131. CONCLUSIONS: This study demonstrated circulating MDR E. coli in the Nigerian community. Monitoring of antimicrobial resistance in developing countries is necessary to optimize empiric treatment and the prudent use of antimicrobials.

bla CTX-M-I group extended spectrum beta lactamase-producing Salmonella typhi from hospitalized patients in Lagos, Nigeria.

PURPOSE: The global spread of bla CTX-M-I extended-spectrum beta-lactamase (ESBL)-producing Salmonella spp. remains a major threat to treatment and control. Evidence of emergence and spread of this marker are lacking in Nigeria. This study investigated bla CTX-M-I ESBL production among Salmonella isolates from hospitalized patients. METHODS: Patients (158 total) made up of two groups were evaluated. Group A was composed of 135 patients with persistent pyrexia and group B was composed of 23 gastroenteritis patients and their stool samples. Samples were cultured, and isolates were identified and were subjected to antibiotic susceptibility testing by standard methods. Isolates were further screened for ESBL production, bla CTX-M-I genes and transferability by double disk synergy test, plasmid extraction, polymerase chain reaction, and conjugation experiment. RESULTS: Thirty-five (25.9%) Salmonella isolates were identified from group A, of which 74.3% were S. typhi, 22.9% were S. paratyphi and two (5.7%) were invasive non-typhoidal S. enteritidis. Nine Plasmodium falciparum infections were recorded, four of which were identified as co-infections with typhoidal Salmonella. Only two (8.7%) S. enteritidis samples were obtained from group B (P>0.05). A total of 24 isolates were ESBL-positive, eliciting resistance to five to seven antibiotics, and were multiple-drug resistant. ESBL production due to the bla CTX-M-I gene cluster was detected in eleven (45.8%) Salmonella isolates. Nine (81.8%) of the eleven bla CTX-M-I ESBL producers were S. typhi and two (18.2%) isolates were S. enteritidis. Four of nine S. typhi bla CTX-M-I ESBL-producing strains harbored 23 kb self-transmissible plasmid that was co-transferred with cefotaxime and augmentin resistance to Escherichia coli j53-2 transconjugants. CONCLUSION: This study revealed the emergence of bla CTX-M-I S. typhi as an agent of persistent pyrexia with potential to spread to other Enterobacteriaceae in Lagos, Nigeria. Cautionary prescription and judicious use of third-generation cephalosporins, particularly cefotaxime, for the treatment of typhoid fever and routine screening for P. falciparum co-infection with ESBL-producing Salmonella in the laboratories during diagnosis of persistent pyrexia conditions in patients are recommended.

Prevalence and Antimicrobial Resistance in Escherichia coli from Food Animals in Lagos, Nigeria.

Foodborne bacteria are often associated with human infections; these infections can become more complicated to treat if the bacteria are also resistant to antimicrobials. In this study, prevalence, antimicrobial resistance, and genetic relatedness of Escherichia coli among food producing animals from Lagos, Nigeria, was investigated. From December 2012 to June 2013, E. coli were isolated from fecal samples of healthy cattle, chicken, and swine. Antimicrobial susceptibility testing against 22 antimicrobials was performed using broth microdilution with the Sensititre™ system. Clonal types were determined by pulsed-field gel electrophoresis (PFGE). From the analysis, 211/238 (88.7%), 170/210 (81%), and 136/152 (89.5%) samples from cattle, chicken, and swine, respectively, were positive for E. coli. A subset of those isolates (n=211) selected based on ß-lactamase production was chosen for further study. Overall, E. coli exhibited the highest resistance to tetracycline (124/211; 58.8%), trimethoprim/sulfamethoxazole (84/211; 39.8%), and ampicillin (72/211; 34.1%). Approximately 40% of the isolates were pan-susceptible, and none of the isolates were resistant to amikacin, cefepime, ceftazidime, ertapenem, meropenem, or tigecycline. Among the resistant isolates, 28 different resistance patterns were observed; 26 of those were characterized as multi-drug resistant (MDR; resistance to ≥2 antimicrobials). One isolate was resistant to 13 different antimicrobials representing five different antimicrobial classes. Using PFGE, MDR E. coli were genetically diverse and overall did not group based on source; identical PFGE patterns were detected among isolates from different sources. These results suggest that isolates cannot be attributed to specific sources, and some may be present across all of the sources. Results from this study indicate that food-producing animals in Nigeria are a reservoir of MDR E. coli that may be transferred to humans via the food chain.

Assessment of competence of participants before and after 7-day intensive malaria microscopy training courses in Nigeria.

Background: The accuracy of malaria diagnosis by microscopy has been a challenge in health facilities in Nigeria due to poor competence of microscopists and inability to report on malaria species other than Plasmodium falciparum. Short microscopy courses were conducted to improve the skills of laboratory personnel to perform malaria microscopy in public health facilities in Nigeria. Materials and Methods: Seven-day malaria microscopy courses were conducted annually between 2011 and 2013 for microscopists in public health facilities. The training courses contained theoretical and practical sessions. Impact of the training was evaluated by practical and theoretical pre- and post-training assessments on malaria slide reading, parasite enumeration and basic malariology. Results: The 102 participants who completed the training consisted of medical laboratory scientists (62; 60.8%), medical laboratory technicians (24; 23.5%) and other healthcare workers (16; 15.7%). The knowledge of basic malariology (theory) at pre- and post-tests were 34% (95% CI 31.7-36.3%) and 74.9% (95% CI 71.8-78.0%), respectively (P<0.001). The mean slide reading detection, species and counting agreements in pre-training assessment were 48.9%, 27.9% and 0%, respectively, and in post-training 56.8%, 39.2% and 25%, respectively. The mean species agreements in picture test pre- and post-training were 21.9% and 55.1%, respectively. There were significant differences (P<0.05) in the median pre-test scores in picture tests and basic malariology of the three categories of participants but not in malaria slide reading and parasite counting tests. However, post-training, a significant difference in test scores of the three categories of participants was recorded only for basic malariology (P=0.0003). Conclusions: The 7-day malaria microscopy courses significantly increased the knowledge and microscopy skills of the trainees and were sufficient to bridge the significant difference in baseline microscopy skills of the different categories of trainees that participated in the training courses.