Assessment of the Presence of Resistance Genes Detected from the Environment and Selected Food Products in Benin

Environmental Risk Factors Contributing to the Spread of Antibiotic Resistance in West Africa

Antibiotic resistance is a well-documented global health challenge that disproportionately impacts low- and middle-income countries. In 2019, the number of deaths attributed to and associated with antibiotic resistance in Western Sub-Saharan Africa was approximately 27 and 115 per 100,000, respectively, higher than in other regions worldwide. Extensive research has consistently confirmed the persistent presence and spread of antibiotic resistance in hospitals, among livestock, within food supply chains, and across various environmental contexts. This review documents the environmental risk factors contributing to the spread of antibiotic resistance in West Africa. We collected studies from multiple West African countries using the Web of Science and PubMed databases. We screened them for factors associated with antibiotic-resistant bacteria and resistance genes between 2018 and 2024. Our findings indicate that antibiotic resistance remains a significant concern in West Africa, with environmental pollution and waste management identified as major factors in the proliferation of antibiotic-resistant bacteria and resistance genes between 2018 and 2024. Additional contributing factors include poor hygiene, the use of antibiotics in agriculture, aquaculture, and animal farming, and the transmission of antibiotic resistance within hospital settings. Unfortunately, the lack of comprehensive genetic characterization of antibiotic-resistant bacteria and resistance genes hinders a thorough understanding of this critical issue in the region. Since antibiotic resistance transcends national borders and can spread within and between countries, it is essential to understand the environmental risk factors driving its dissemination in West African countries. Such understanding will be instrumental in developing and recommending effective strategies nationally and internationally to combat antibiotic resistance.

Comparative analysis of virulence gene profiles of Escherichia coli from human and non-human sources in Rivers State, Nigeria

Traditionally, the presence of virulence features has been thought to be a key factor in differentiating pathogenic from commensal strains. An understanding of the virulence potential of Escherichia coli isolates from various sources is essential to shed light on potential contamination/transmission rates between the various sources. This study was therefore aimed at exploring the occurrence of specific virulence genes and gene profiles associated with E. coli from human and non-human sources in Rivers State, Nigeria. Two hundred samples from human (urine and faeces) and non-human (soil and poultry droppings) sources (50 each) were analysed using standard microbiological procedures. DNA was extracted from isolates presumptively identified as E. coli using the Presto Mini gDNA Bacteria-Kit Quick protocol following the manufacturer's instructions. Isolate identities were confirmed using E. coli-specific 16S rRNA primers, and confirmed isolates were screened for the presence of six virulence genes [afimbriae binding adhesin (afa), type 1 fimbriae (fimH) and P-fimbrial usher protein (papC)], iron acquisition systems: aerobactin (aer), cytotoxic necrotizing factor I (cnf1) and alpha-hemolysin (hly). Results showed that all isolates harboured at least one of the tested virulence genes, with fimH (97%) as the most prevalent virulence gene and papC the least commonly occurring (35%). A higher occurrence of virulence genes was noted in non-human isolates, though hly and cnf were not detected at all in any of the isolates studied (0%). Ten different profiles were observed with the afaCc-aer-fimH profile the most commonly occurring virulence gene profile being in general (33.3%). For non-human isolates, however, aer-afaCc-fimH-papC was the most commonly occurring profile (42.9%). This study shows that the test E. coli from human and non-human sources do not carry distinct virulence gene profiles. Studies on a larger subset of isolates would however be necessary to determine if the virulence genes tested in this study really cannot be used to tell whether an isolate is from a human source or not in the South-South of Nigeria.

Prevalence, antibiotic resistance, and virulence gene profile of Escherichia coli strains shared between food and other sources in Africa: A systematic review

Background and Aim

Foodborne diseases caused by Escherichia coli are prevalent globally. Treatment is challenging due to antibiotic resistance in bacteria, except for foodborne infections due to Shiga toxin-producing E. coli, for which treatment is symptomatic. Several studies have been conducted in Africa on antibiotic resistance of E. coli isolated from several sources. The prevalence and distribution of resistant pathogenic E. coli isolated from food, human, and animal sources and environmental samples and their virulence gene profiles were systematically reviewed.

Materials and Methods

Bibliographic searches were performed using four databases. Research articles published between 2000 and 2022 on antibiotic susceptibility and virulence gene profile of E. coli isolated from food and other sources were selected.

Results

In total, 64 articles were selected from 14 African countries: 45% of the studies were conducted on food, 34% on animal samples, 21% on human disease surveillance, and 13% on environmental samples. According to these studies, E. coli is resistant to ~50 antimicrobial agents, multidrug-resistant, and can transmit at least 37 types of virulence genes. Polymerase chain reaction was used to characterize E. coli and determine virulence genes.

Conclusion

A significant variation in epidemiological data was noticed within countries, authors, and sources (settings). These results can be used as an updated database for monitoring E. coli resistance in Africa. More studies using state-of-the-art equipment are needed to determine all resistance and virulence genes in pathogenic E. coli isolated in Africa.

Characterization of uropathogenic Escherichia coli phylogroups associated with antimicrobial resistance, virulence factor distribution, and virulence-related phenotypes

In this study, we compared the characteristics of different uropathogenic Escherichia coli phylogroups. A total of 844 E. coli isolated from urine were enrolled and the antimicrobial susceptibility of E. coli to 22 antibiotics was determined by disk diffusion test. The distribution of phylogroups and 20 virulence factor genes was determined by PCR. Phenotypes associated with bacterial virulence, including motility, biofilm formation, and the production of curli and siderophore, were examined. Phylogroup B2 was dominant in our isolates (64.8%), followed by phylogroups D (8.6%), B1 (7.8%), F (6.0%), C (4.5%), A (3.1%), untypable (2.8%), E (1.8%), and clade I (0.5%). The prevalence of multidrug-resistant strains was highest in phylogroup C (86.8%), followed by E (80.0%), F (75.0%), and D (71.2%). Moreover, 23.5% of the phylogroup F E. coli were extensively drug-resistant. Phylogroup B2 E. coli had an average of the highest virulence factor genes (10.1 genes/isolate). Compared to phylogroup B2 E. coli, phylogroups F and clade I E. coli had higher motility while phylogroup C E. coli had lower motility. >60% of phylogroups A and C E. coli showed very low curli production. In contrast, 14%, 10%, and 7%, of E. coli in phylogroups F, B2, and E, produced a very high amount of curli, respectively. Surprisingly, phylogroup A E. coli showed the highest virulence to larvae, followed by phylogroups B2 and C. In summary, we first characterized and revealed that the antimicrobial resistance, virulence gene distribution, motility, and curli production, were associated with in E. coli phylogroups.

Taxonomic characterization of Pseudomonas hygromyciniae sp. nov., a novel species discovered from a commercially purchased antibiotic

In an attempt to identify novel bacterial species, microbiologists have examined a wide range of environmental niches. We describe the serendipitous discovery of a novel gram-negative bacterial species from a different type of extreme niche: a purchased vial of antibiotic. The vial of antibiotic hygromycin B was found to be factory contaminated with a bacterial species, which we designate Pseudomonas hygromyciniae sp. nov. The proposed novel species belongs to the P. fluorescens complex and is most closely related to P. brenneri, P. proteolytica, and P. fluorescens. The type strain Pseudomonas hygromyciniae sp. nov. strain SDM007T (SDM007T) harbors a novel 250 kb megaplasmid which confers resistance to hygromycin B and contains numerous other genes predicted to encode replication and conjugation machinery. SDM007T grows in hygromycin concentrations of up to 5 mg/mL but does not use the antibiotic as a carbon or nitrogen source. While unable to grow at 37°C ruling out its ability to infect humans, it grows and survives at temperatures between 4 and 30°C. SDM007T can infect plants, as demonstrated by the lettuce leaf model, and is highly virulent in the Galleria mellonella infection model but is unable to infect mammalian A549 cells. These findings indicate that commercially manufactured antibiotics represent another extreme environment that may support the growth of novel bacterial species. IMPORTANCE Physical and biological stresses in extreme environments may select for bacteria not found in conventional environments providing researchers with the opportunity to not only discover novel species but to uncover new enzymes, biomolecules, and biochemical pathways. This strategy has been successful in harsh niches such as hot springs, deep ocean trenches, and hypersaline brine pools. Bacteria belonging to the Pseudomonas species are often found to survive in these unusual environments, making them relevant to healthcare, food, and manufacturing industries. Their ability to survive in a variety of environments is mainly due to the high genotypic and phenotypic diversity displayed by this genus. In this study, we discovered a novel Pseudomonas sp. from a desiccated environment of a sealed antibiotic bottle that was considered sterile. A close genetic relationship with its phylogenetic neighbors reiterated the need to use not just DNA-based tools but also biochemical characteristics to accurately classify this organism.

A review of some medicinal plants with the potential to defeat antimicrobial resistance: Cases of Benin, Togo, Ghana, Burkina Faso, and Cape Verde

Antimicrobial resistance (AMR) is a global public health problem. In the alternatives being explored for developing new antimicrobials, medicinal plants occupy an important place, particularly in Africa, where they are widely used. This review aims to analyze the potential of medicinal plants from Benin, Togo, Ghana, Burkina-Faso, and Cape Verde in the fight against AMR. A bibliographic search was conducted to explore scientific databases such as PubMed and Google Scholar. During this search, particular attention was given to epidemiological data related to AMR in these countries, medicinal plants traditionally used to treat microbial infections and medicinal plants that have been shown to be active on multidrug-resistant microbial strains. In total, 94 manuscripts were investigated. Epidemiological data showed that the problem of AMR is worsening in each target country. In addition, several medicinal plants have been demonstrated to be effective against microbial strains resistant to conventional antibiotics. A total of 532 medicinal plants were identified according to their ethnomedical uses for the treatment of microbial infections. Scientific evidence was collected on the antimicrobial potential of 91 plants. This study showed the potential of medicinal plants in the fight against AMR. Their documented traditional use, coupled with the evidence of efficacy provided, make them interesting sources for developing new antimicrobials.

Characterisation and antibiotic resistance of Yersinia enterocolitica from various meat categories, South Africa

Yersinia enterocolitica infections impose a significant public health and socioeconomic burden on human population in many countries. The current study investigated the prevalence, antimicrobial resistance profile and molecular diversity of Y. enterocolitica in meat and meat products across various retail outlets in selected provinces of South Africa (SA). In a cross-sectional study, a total of 581 retail meat and meat products were collected from four cities across three provinces of SA. Samples were from beef and pork products, which included 292 raw intact, 167 raw processed, and 122 ready-to-eat (RTE) meats. Samples were analysed using classical microbiological methods for isolation, identification and biotyping of Y. enterocolitica. Conventional polymerase chain reaction (PCR) was performed for confirmation, serotyping, screening of virulence (n = 11) and antimicrobial resistance (n = 18) genes. Phenotypic antimicrobial resistance profiles were determined against 12 antibiotics discs, using disc diffusion method. The overall prevalence of 12% (70/581) was reported across all cities with contamination proportion reported in samples collected from raw intact 15% (43/292), followed by raw processed 11% (18/167) and RTE meats 7% (9/122). All positive isolates were of biotype 1A with 7% (5/70) belonging to bioserotype 1A/O:8. Most of the isolates harboured ymoA, ystB, fepD, ail, fepA, invA and myfA virulence genes. High antimicrobial resistance frequency was observed for ampicillin (94%), cephalothin (83%) and amoxicillin (41%), respectively. Of the 18 tested antimicrobial resistance genes, blaTEM was the most predominant (40%) followed by cmlA (21%). This study reveals the presence of antimicrobial resistant Y. enterocolitica possessing virulent genes of public health importance in products of animal origin, therefore, health monitoring and surveillance of this pathogen is required.

Pseudomonas fluorescens Complex and Its Intrinsic, Adaptive, and Acquired Antimicrobial Resistance Mechanisms in Pristine and Human-Impacted Sites

Pseudomonas spp. are ubiquitous microorganisms that exhibit intrinsic and acquired resistance to many antimicrobial agents. Pseudomonas aeruginosa is the most studied species of this genus due to its clinical importance. In contrast, the Pseudomonas fluorescens complex consists of environmental and, in some cases, pathogenic opportunistic microorganisms. The records of antimicrobial-resistant P. fluorescens are quite scattered, which hinders the recognition of patterns. This review compiles published data on antimicrobial resistance in species belonging to the P. fluorescens complex, which were identified through phylogenomic analyses. Additionally, we explored the occurrence of clinically relevant antimicrobial resistance genes in the genomes of the respective species available in the NCBI database. Isolates were organized into two categories: strains isolated from pristine sites and strains isolated from human-impacted or metal-polluted sites. Our review revealed that many reported resistant phenotypes in this complex might be related to intrinsic features, whereas some of them might be ascribed to adaptive mechanisms such as colistin resistance. Moreover, a few studies reported antimicrobial resistance genes (ARGs), mainly β-lactamases. In-silico analysis corroborated the low occurrence of transferable resistance mechanisms in this Pseudomonas complex. Both phenotypic and genotypic assays are necessary to gain insights into the evolutionary aspects of antimicrobial resistance in the P. fluorescens complex and the possible role of these ubiquitous species as reservoirs of clinically important and transmissible ARGs.