Bacteria In Africa Research Articles

In silico studies and antimicrobial investigation of synthesised novel N-acylhydrazone derivatives of indole

Indole is an exceptional scaffold in the discovery and design of drugs with different mechanisms and biological activity. Numerous research has been conducted on N-acylhydrazones of indole and its derivatives, however, no account of the synthesis, molecular docking and the antimicrobial activities of the eleven synthesised compounds has never been reported. The study was therefore designed to synthesize, characterize, carry out molecular docking and determine the antimicrobial activities of novel N-acylhydrazone derivatives of indole.Aldol condensation of synthesised hydrazides with aromatic aldehydes led to the formation of the N-acylhydrazone derivatives of indole. The structure of the compounds were confirmed by proton nuclear magnetic Resonance (1H NMR) and electron impact mass spectrometry (EIMS). The N-acylhydrazones were screened against ten microbes (four fungi three Gram-positive bacteria, and three Gram-negative bacteria) at concentrations of 100 to 6.26 mg/mL, using agar well diffusion and fungi carpeted antimicrobial assays. Gentamicin (5 mg/mL) was the positive control for bacteria while tioconazole (70%) was used for fungi. The molecular docking studies was done and the docking scores recorded accordingly on four antimicrobial receptors with PDB codes (3CR7, 3FHV, 6L1L and 6SPC).The synthesised compounds displayed moderate activity against the test organisms with the zone of inhibitions range 24 ± 0.00 to 18 ± 0.70 mm at 100 mg/mL as compared to the standards (gentamicin 10 µg/mL (36 ± 1.41), tioconazole 70% (26 ± 4.24)). All synthesised N-acylhydrazone derivatives exhibited a good number of hydrophobic interactions, classical and non-classical hydrogen bonding with the docked protein enzymes. Compound 10 and 1 were predicted to exhibit highest binding energy of -9.7 and -9.2 kcal/mole respectively with the binding site of 6SPC. Other compounds were found to have higher predicted binding energies than the standard drugs. Previously, there has been no report on the synthesis of N-acylhydrazone derivatives of Indole used in this study, their molecular docking and antimicrobial analyses is being reported for the first time. Since microbial resistance poses a major threat to human health globally, this research screened the synthesised compounds on fungi and bacteria and were found to be active against the selected microbes. These compounds if ameliorated, will reduce the uncontrollable rise in the multidrug-resistant (MDR) bacteria in Africa and in the universe.Therefore, since the synthesised N-acylhydrazone derivatives have potential in inhibiting microbial growth and showed good binding parameters with the tested enzymes, they could be effectively developed into antimicrobial agents useful for treating a wide range of microbial infections. Further research should conducted on the drugability, toxicity, minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of the drug compounds.

Prevalence and Traits of Mobile Colistin Resistance Gene Harbouring Isolates from Different Ecosystems in Africa.

The mobile colistin resistance (mcr) gene threatens the efficacy of colistin (COL), a last-line antibiotic used in treating deadly infections. For more than six decades, COL is used in livestock around the globe, including Africa. The use of critically important antimicrobial agents, like COL, is largely unregulated in Africa, and many other factors militate against effective antimicrobial stewardship in the continent. Currently, ten mcr genes (mcr-1 to mcr-10) have been described. In Africa, mcr-1, mcr-2, mcr-3, mcr-5, mcr-8, and mcr-9 have been detected in isolates from humans, animals, foods of animal origin, and the environment. These genes are harboured by Escherichia coli, Klebsiella, Salmonella, Citrobacter, Enterobacter, Pseudomonas, Aeromonas, Alcaligenes, and Acinetobacter baumannii isolates. Different conjugative and nonconjugative plasmids form the backbone for mcr in these isolates; however, mcr-1 and mcr-3 have also been integrated into the chromosome of some African strains. Insertion sequences (ISs) (especially ISApl1), either located upstream or downstream of mcr, class 1 integrons, and transposons, are drivers of mcr in Africa. Genes coding multi/extensive drug resistance and virulence are colocated with mcr on plasmids in African strains. Transmission of mcr to/among African strains is nonclonal. Contact with mcr-habouring reservoirs, the consumption of contaminated foods of animal/plant origin or fluid, animal-/plant-based food trade and travel serve as exportation, importation, and transmission routes of mcr gene-containing bacteria in Africa. Herein, the current status of plasmid-mediated COL resistance in humans, food-producing animals, foods of animal origin, and environment in Africa is discussed.

Genomic and Resistance Epidemiology of Gram-Negative Bacteria in Africa: a Systematic Review and Phylogenomic Analyses from a One Health Perspective.

Antibiotic resistance (AR) remains a major threat to public and animal health globally. However, AR ramifications in developing countries are worsened by limited molecular diagnostics, expensive therapeutics, inadequate numbers of skilled clinicians and scientists, and unsanitary environments. The epidemiology of Gram-negative bacteria, their AR genes, and geographical distribution in Africa are described here. Data were extracted and analyzed from English-language articles published between 2015 and December 2019. The genomes and AR genes of the various species, obtained from the Pathosystems Resource Integration Center (PATRIC) and NCBI were analyzed phylogenetically using Randomized Axelerated Maximum Likelihood (RAxML) and annotated with Figtree. The geographic location of resistant clones/clades was mapped manually. Thirty species from 31 countries and 24 genera from 41 countries were analyzed from 146 articles and 3,028 genomes, respectively. Genes mediating resistance to β-lactams (including bla TEM-1, bla CTX-M, bla NDM, bla IMP, bla VIM, and bla OXA-48/181), fluoroquinolones (oqxAB, qnrA/B/D/S, gyrA/B, and parCE mutations, etc.), aminoglycosides (including armA and rmtC/F), sulfonamides (sul1/2/3), trimethoprim (dfrA), tetracycline [tet(A/B/C/D/G/O/M/39)], colistin (mcr-1), phenicols (catA/B, cmlA), and fosfomycin (fosA) were mostly found in Enterobacter spp. and Klebsiella pneumoniae, and also in Serratia marcescens, Escherichia coli, Salmonella enterica, Pseudomonas, Acinetobacter baumannii, etc., on mostly IncF-type, IncX3/4, ColRNAI, and IncR plasmids, within IntI1 gene cassettes, insertion sequences, and transposons. Clonal and multiclonal outbreaks and dissemination of resistance genes across species and countries and between humans, animals, plants, and the environment were observed; Escherichia coli ST103, K. pneumoniae ST101, S. enterica ST1/2, and Vibrio cholerae ST69/515 were common strains. Most pathogens were of human origin, and zoonotic transmissions were relatively limited.IMPORTANCE Antibiotic resistance (AR) is one of the major public health threats and challenges to effective containment and treatment of infectious bacterial diseases worldwide. Here, we used different methods to map out the geographical hot spots, sources, and evolutionary epidemiology of AR. Escherichia coli, Klebsiella pneumoniae, Salmonella enterica, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter spp., Neisseria meningitis/gonorrhoeae, Vibrio cholerae, Campylobacter jejuni, etc., were common pathogens shuttling AR genes in Africa. Transmission of the same clones/strains across countries and between animals, humans, plants, and the environment was observed. We recommend Enterobacter spp. or K. pneumoniae as better sentinel species for AR surveillance.

Carbapenemase-Producing Non-Glucose-Fermenting Gram-Negative Bacilli in Africa, Pseudomonas aeruginosa and Acinetobacter baumannii: A Systematic Review and Meta-Analysis.

Background Studies have reported that the existence of CP bacteria in Africa, but, in general, comprehensive data about the molecular epidemiology of CP organisms are limited. Therefore, this systematic review and meta-analysis expound the pooled prevalence of CP P. aeruginosa and CP A. baumannii clinical isolates in Africa. It also identified the diversity of carbapenemases or their encoding genes among the isolates in Africa. Lastly, the review observed the trends of these CP isolates in Africa. Methods A comprehensive search was performed between July 2019 and October 2019 in the following databases: PubMed, Google Scholar, and African Journal online. The included articles were published only in English. The screening was done by two authors independently. The data extracted on Excel spreadsheet were transferred to STATA 11 software for analysis. Results From a total of 1,454 articles searched, 42 articles were eligible. Most of the studies were conducted in the North Africa region. But there was no report from Central Africa. The pooled prevalence of CP P. aeruginosa and CP A. baumannii among the clinical specimens in Africa was 21.36% and 56.97%, respectively. OXA-23 and VIM were the most prevailing carbapenemase among P. aeruginosa and A. baumannii, respectively. The cumulative meta-analysis revealed a relative increment of the prevalence of CP P. aeruginosa over time in Africa but it showed a higher prevalence of CP A. baumannii isolates across years. Conclusion The review revealed a high pooled prevalence of CP A. baumannii clinical isolates in Africa which needs urgent action. Moreover, the emergence of concomitant carbapenemases, especially OXA-23 + NDM among CP A. baumannii, was also an alarming problem.

Molecular epidemiology and mechanisms of antibiotic resistance in Enterococcus spp., Staphylococcus spp., and Streptococcus spp. in Africa: a systematic review from a One Health perspective.

A systematic review of antibiotic-resistant Gram-positive bacteria in Africa from a One Health perspective is lacking. Here, we report result from a search for English-language articles on the resistance mechanisms and clonality of Gram-positive bacteria in Africa between 2007 and 2019 reported in PubMed, Web of Science, ScienceDirect, and African Journals OnLine; 172 studies from 22 different African countries were identified. Resistance genes, such as mecA, erm(B), erm(C), tet(M), tet(K), tet(L), vanB, vanA, vanC, and tet(O), were found to be common. Staphylococcus spp., Enterococcus spp., and Streptococcus spp. were the main species reported by the studies, with clones such as Staphylococcus aureus ST5 (n=218 isolates), ST8 (n=127 isolates), ST80 (n=133 isolates), and ST88 (n=117 isolates), and mobile genetic elements such as IS16 (n=28 isolates), IS256 (n=96), Tn916 (n=107 isolates), and SCCmec (n=4437 isolates) identified. SCCmec IV (n=747 isolates) was predominant, followed by SCCmec III (n=305 isolates), SCCmec II (n=163 isolates), SCCmec V (n=135 isolates), and SCCmec I (n=79 isolates). Resistance to penicillin (n=5926 isolates), tetracycline (n=5300 isolates), erythromycin (n=5151 isolates), rifampicin (n=3823 isolates), gentamycin (n=3494 isolates), sulfamethoxazole/trimethoprim (n=3089 isolates), and ciprofloxacin (n=2746 isolates) was common in most reports from 22 countries. Clonal dissemination of resistance across countries and between humans, animals, and the environment was observed. Resistance rates ranged from 1.4% to 100% for 15 of the studies; 10 were One Health-related studies. Strict infection control measures, antimicrobial stewardship, and periodic One Health epidemiological surveillance studies are needed to monitor and contain the threat of increasing antibiotic resistance in Africa.

Correction: Classes 1 and 2 integrons in faecal Escherichia coli strains isolated from mother-child pairs in Nigeria.

[This corrects the article DOI: 10.1371/journal.pone.0183383.].

Classes 1 and 2 integrons in faecal Escherichia coli strains isolated from mother-child pairs in Nigeria.

BackgroundAntimicrobial resistance among enteric bacteria in Africa is increasingly mediated by integrons on horizontally acquired genetic elements. There have been recent reports of such elements in invasive pathogens across Africa, but very little is known about the faecal reservoir of integron-borne genes.Methods and findingsWe screened 1098 faecal Escherichia coli isolates from 134 mother-child pairs for integron cassettes by PCR using primers that anneal to the 5’ and 3’ conserved ends of the cassette regions and for plasmid replicons. Genetic relatedness of isolates was determined by flagellin and multi-locus sequence typing. Integron cassettes were amplified in 410 (37.5%) isolates and were significantly associated with resistance to trimethoprim and multiple resistance. Ten cassette combinations were found in class 1 and two in class 2 integrons. The most common class 1 cassette configurations were single aadA1 (23.4%), dfrA7 (18.3%) and dfrA5 (14.4%). Class 2 cassette configurations were all either dfrA1-satI-aadA1 (n = 31, 7.6%) or dfrA1-satI (n = 13, 3.2%). A dfr cassette was detected in 294 (31.1%) of trimethoprim resistant strains and an aadA cassette in 242 (23%) of streptomycin resistant strains. Strains bearing integrons carried a wide range of plasmid replicons of which FIB/Y (n = 169; 41.2%) was the most frequently detected. Nine isolates from five different individuals carried the dfrA17-aadA5-bearing ST69 clonal group A (CGA). The same integron cassette combination was identified from multiple distinct isolates within the same host and between four mother-child pairs.ConclusionsIntegrons are important determinants of resistance in faecal E. coli. Plasmids in integron-containing strains may contribute to dispersing resistance genes. There is a need for improved surveillance for resistance and its mechanisms of dissemination and persistence and mobility of resistance genes in the community and clinical settings.

The spread of carbapenemase-producing bacteria in Africa: a systematic review

Carbapenems are the last line of defence against ever more prevalent MDR Gram-negative bacteria, but their efficacy is threatened worldwide by bacteria that produce carbapenemase enzymes. The epidemiology of bacteria producing carbapenemases has been described in considerable detail in Europe, North America and Asia; however, little is known about their spread and clinical relevance in Africa. We systematically searched in PubMed, EBSCOhost, Web of Science, Scopus, Elsevier Masson Consulte and African Journals Online, international conference proceedings, published theses and dissertations for studies reporting on carbapenemase-producing bacteria in Africa. We included articles published in English or French up to 28 February 2014. We calculated the prevalence of carbapenemase producers only including studies where the total number of isolates tested was at least 30. Eighty-three studies were included and analysed. Most studies were conducted in North Africa (74%, 61/83), followed by Southern Africa (12%, 10/83), especially South Africa (90%, 9/10), West Africa (8%, 7/83) and East Africa (6%, 6/83). Carbapenemase-producing bacteria were isolated from humans, the hospital environment and community environmental water samples, but not from animals. The prevalence of carbapenemase-producing isolates in hospital settings ranged from 2.3% to 67.7% in North Africa and from 9% to 60% in sub-Saharan Africa. Carbapenemase-producing bacteria have been described in many African countries; however, their prevalence is poorly defined and has not been systematically studied. Antibiotic stewardship and surveillance systems, including molecular detection and genotyping of resistant isolates, should be implemented to monitor and reduce the spread of carbapenemase-producing bacteria.

Staphylococcus aureus, Streptococcus pneumoniae, and Streptocccus pyogenes DNA are common in febrile patients in Senegal

Background: The repertoire of fever-causing bacteria in Africa has been neglected. This study aimed to compare the epidemiology of Staphyloccus aureus, Streptococcus pneumoniae, and Streptococcus pyogenes bacteremia in Senegal. Methods & Materials: From June 2010 to March 2012, we conducted a prospective study on 2,024 blood specimens from febrile patients from 5 different areas in Senegal and 400 non-febrile individuals from 1 of this area. Quantitative real-time PCR targeting Staphyloccus aureus, Streptococcus pneumoniae, and Streptococcus pyogenes were performed. Results: The prevalence of S. pneumoniae in febrile patients was 21.2% (429/2,024). Infections occurred primarily during the dry season rather than the rainy season (23.9% vs. 19%, respectively; p =0.01) and were significantly higher in patients less 16 years (24.8%) than older (13.2%; p<10-3). The highest prevalence was observed in Kedougou, reaching 32.6% andwas significantly higher than that of the 4 other sites: Casamance (25.3%, p =0.03), Keur Momar Sarr (21.5%; p=0.005), Niakhar (18%, p <10-3), and SineSaloum(16%;p<10-3). TheprevalenceofS. aureus in febrilepatients was 19.8% (400/2,024); infections occurred primarily during the rainy season rather than the dry season (25.1% vs. 13.3%, respectively; p <10-3). The occurrence of S. aureuswas not correlatedwith the age. The highest prevalence was observed in Kedougou, reaching 33% and was significantly higher than that of 3 other sites: Casamance (22.9%, p =0.003), Niakhar (16.1%, p <10-3), and SineSaloum (13%; p<10-3). The prevalence of S. pyogenes in febrile patients was 4.6% (93/2,024); infections occurred equally during the dry season and rainy seasons. The occurrence of S. pyogenes was higher in patients less 16 years (5.6%) than older (2%;p<10-3). The highest prevalence was observed in Niakhar reaching 10.1% and was significantly higher than that of the other sites: Kedougou (6.2%,p =0.001), Casamance (4.6%,p <10-3), KeurMomarSarr (4.5%; p<10-3), and Sine-Saloum (2%; p<10-3). Among apyretic people, 7 were positive for S. aureus (1.75%), 1 for S. pneumoniae (0.25%) and 0 for S. pyogenes. Conclusion: S. aureus and S. pneumoniae DNA are common in blood of patients with fever in Senegal.

The radiological manifestations of acute exacerbations of COPD

Background: The repertoire of fever-causing bacteria in Africa has been neglected. This study aimed to compare the epidemiology of Staphyloccus aureus, Streptococcus pneumoniae, and Streptococcus pyogenes bacteremia in Senegal. Methods & Materials: From June 2010 to March 2012, we conducted a prospective study on 2,024 blood specimens from febrile patients from 5 different areas in Senegal and 400 non-febrile individuals from 1 of this area. Quantitative real-time PCR targeting Staphyloccus aureus, Streptococcus pneumoniae, and Streptococcus pyogenes were performed. Results: The prevalence of S. pneumoniae in febrile patients was 21.2% (429/2,024). Infections occurred primarily during the dry season rather than the rainy season (23.9% vs. 19%, respectively; p =0.01) and were significantly higher in patients less 16 years (24.8%) than older (13.2%; p<10-3). The highest prevalence was observed in Kedougou, reaching 32.6% andwas significantly higher than that of the 4 other sites: Casamance (25.3%, p =0.03), Keur Momar Sarr (21.5%; p=0.005), Niakhar (18%, p <10-3), and SineSaloum(16%;p<10-3). TheprevalenceofS. aureus in febrilepatients was 19.8% (400/2,024); infections occurred primarily during the rainy season rather than the dry season (25.1% vs. 13.3%, respectively; p <10-3). The occurrence of S. aureuswas not correlatedwith the age. The highest prevalence was observed in Kedougou, reaching 33% and was significantly higher than that of 3 other sites: Casamance (22.9%, p =0.003), Niakhar (16.1%, p <10-3), and SineSaloum (13%; p<10-3). The prevalence of S. pyogenes in febrile patients was 4.6% (93/2,024); infections occurred equally during the dry season and rainy seasons. The occurrence of S. pyogenes was higher in patients less 16 years (5.6%) than older (2%;p<10-3). The highest prevalence was observed in Niakhar reaching 10.1% and was significantly higher than that of the other sites: Kedougou (6.2%,p =0.001), Casamance (4.6%,p <10-3), KeurMomarSarr (4.5%; p<10-3), and Sine-Saloum (2%; p<10-3). Among apyretic people, 7 were positive for S. aureus (1.75%), 1 for S. pneumoniae (0.25%) and 0 for S. pyogenes. Conclusion: S. aureus and S. pneumoniae DNA are common in blood of patients with fever in Senegal.

Enterotoxinogenic bacteria in Africa.

Enterotoxinogenic bacteria in Africa.