Prevalence of colistin-resistant Escherichia coli harbouring mcr-1 in raw beef and ready-to-eat beef products in Egypt

Identification of mcr-2 and mcr-3 Genes in Colistin-Resistant E. coli O157:H7 Isolated From Raw Meat Samples in Beirut, Lebanon

Colistin is a last-resort antibiotic used to treat multidrug-resistant Gram-negative bacterial infections. The global emergence of colistin resistance has been attributed to plasmid-mediated mobile colistin resistance (mcr) genes. In Lebanon, bacteria carrying the mcr-1 gene have increasingly been identified in food animal sources. This study is aimed at detecting colistin-resistant Shiga toxigenic Escherichia coli O157:H7 in raw meat samples from local markets in the suburbs of Beirut and evaluating their antimicrobial resistance profiles. A total of 50 meat samples, including 25 minced beef and 25 burger samples, were collected and analyzed. Antimicrobial resistance patterns were determined using the Kirby-Bauer method, while colistin resistance and the presence of mcr-2 and mcr-3 genes were assessed using broth microdilution and PCR amplification techniques. Among these samples, 23 (46%) tested positive for E. coli O157:H7. Resistance to ampicillin and amoxicillin/clavulanic acid was observed in 96% of the samples, while 61% were resistant to trimethoprim/sulfamethoxazole, and 43% to chloramphenicol. Notably, 87% of the samples displayed colistin resistance, with a minimum inhibitory concentration (MIC) of ≥ 4 μg/mL. The mcr-2 gene was present in four isolates (17.4%), and the mcr-3 gene was identified in 10 isolates (43.4%). This study is the first to document the presence of plasmid-mediated colistin resistance genes, mcr-2 and mcr-3, in E. coli O157:H7 strains in Lebanon. These findings highlight a serious public health concern for the Lebanese community. Therefore, the responsible use of antibiotics across all healthcare sectors, combined with strict hygiene measures in food handling, is essential to control the spread of colistin-resistant genes.

A comprehensive review of antibiotic resistance gene contamination in agriculture: Challenges and AI-driven solutions

Since their discovery, the prolonged and widespread use of antibiotics in veterinary and agricultural production has led to numerous problems, particularly the emergence and spread of antibiotic-resistant bacteria (ARB). In addition, other anthropogenic factors accelerate the horizontal transfer of antibiotic resistance genes (ARGs) and amplify their impact. In agricultural environments, animals, manure, and wastewater are the vectors of ARGs that facilitate their spread to the environment and humans via animal products, water, and other environmental pathways. Therefore, this review comprehensively analyzed the current status, removal methods, and future directions of ARGs on farms. This article 1) investigates the origins of ARGs on farms, the pathways and mechanisms of their spread to surrounding environments, and various strategies to mitigate their spread; 2) determines the multiple factors influencing the abundance of ARGs on farms, the pathways through which ARGs spread from farms to the environment, and the effects and mechanisms of non-antibiotic factors on the spread of ARGs; 3) explores methods for controlling ARGs in farm wastes; and 4) provides a comprehensive summary and integration of research across various fields, proposing that in modern smart farms, emerging technologies can be integrated through artificial intelligence to control or even eliminate ARGs. Moreover, challenges and future research directions for controlling ARGs on farms are suggested.

A Systematic Review and Comprehensive Analysis of mcr Gene Prevalence in Bacterial Isolates in Arab Countries

BACKGROUND

The resurgence of colistin has become critical in combating multidrug-resistant Gram-negative bacteria. However, the emergence of mobilized colistin resistance (mcr) genes presents a crucial global challenge, particularly in the Arab world, which includes regions with unique conditions and ongoing conflicts in some parts.

METHODS

To address this issue, a systematic review was conducted using multiple databases, including Cochrane, PubMed, Scopus, Web of Science, and Arab World Research Source.

RESULTS

A total of 153 studies were included, revealing substantial heterogeneity in the prevalence of mcr genes across 15 Arab countries, with notable findings indicating that Egypt and Lebanon reported the highest number of cases. The analysis indicated that the most prevalent sequence types were ST10, ST101, and ST1011, all of which are Escherichia coli strains linked to significant levels of colistin resistance and multiple antimicrobial resistance profiles.

CONCLUSIONS

By analyzing the diverse findings from different Arab countries, this review lays a critical foundation for future research and highlights the necessity for enhanced surveillance and targeted interventions to address the looming threat of colistin resistance in the region.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42024584379.

First Report on the Occurrence and Antibiotic Resistance Profile of Colistin-Resistant Escherichia coli in Raw Beef and Cow Feces in Vietnam

Colistin-resistant Escherichia coli (COE) has been recently recognized as a serious threat to animal and human health. This study aimed to determine the prevalence and antibiotic resistance profile of COE isolated from raw beef and cow feces in Vietnam. Our results showed that 16% (16/100) and 32% (32/100) of raw beef and cow feces samples were positive for COE, respectively. A total of 48 COE strains were isolated, with 16 originating from raw beef and 32 from cow feces samples. The antibiotic susceptibility test revealed that the COE isolates were highly resistant to ampicillin, tetracycline, florfenicol, trimethoprim/sulfamethoxazole, streptomycin, and nalidixic acid, with resistance rates ranging from 66.67% to 87.5%. In addition, 87.5% of the isolates were identified to be multidrug-resistant strains. Further molecular characterization indicated that all COE isolates carried the mcr-1 gene, with 16 of them also harboring blaCTX-M-55 genes. Taken together, the findings in this study demonstrate that raw beef and cow feces are important sources of COE, which can be potentially transmitted to humans through the food chain.

Potential public health hazards related to consumption of poultry contaminated with antibiotic resistant Listeria monocytogenes in Egypt

Listeria monocytogenes is an important foodborne pathogen that incorporated into many serious infections in human especially immunocompromised individuals, pregnant women, the elderly, and newborns. The consumption of food contaminated with such bacteria is considered a source of potential risk for consumers. Therefore, a total of 250 poultry purchased in highly popular poultry stores besides 50 swabs from workers hands in the same stores, in Mansoura City had been tested for the L. monocytogenes prevalence, virulence genes, and antibiotic resistance profile illustrating the health hazards from such poultry. The L. monocytogenes were recovered from 9.6% of poultry samples while not detected from workers hand swabs. The antimicrobial susceptibility of 24 L. monocytogenes strains against 24 antibiotics of seven different classes revealed high susceptibility rates to erythromycin (79.17%), streptomycin (66.67%), gentamycin (66.67%), vancomycin (58.33%), chloramphenicol (58.33%) and cefotaxime (41.67%). The majority (79.2%) of L. monocytogenes were classified as multidrug resistant strains with high resistance to tetracyclines and β-lactams antibiotics while 16.7% of the strains were categorized as extensively resistant ones. The iap virulence-specific determination gene had been detected in all recovered L. monocytogenes isolates while 83.33 and 70.83% of the isolates harbored hylA and actA genes. In addition, the study confirmed the capability of most L. monocytogenes isolates for biofilm formation by moderate to strong production and the quantitative risk assessment illustrated the risk of developing listeriosis as the risk value exceeded 100. The current results illustrate that poultry meat can be a source of pathogenic antibiotic resistant strains that may cause infection with limited or no treatment in immunosuppressed consumers via the food chain.

The occurrence and molecular detection of mcr-1 and mcr-5 genes in Enterobacteriaceae isolated from poultry and poultry meats in Malaysia

The advent of antimicrobials-resistant (AMR), including colistin-resistant bacteria, poses a significant challenge to animal and human health, food safety, socio-economic growth, and the global environment. This study aimed to ascertain the colistin resistance prevalence and molecular mechanisms of colistin resistance in Enterobacteriaceae. The colistin resistance was determined using broth microdilution assay, PCR; and Sanger sequencing of mcr genes responsible for colistin resistance in Enterobacteriaceae (n = 627), including Escherichia coli (436), Salmonella spp. (n = 140), and Klebsiella pneumoniae (n = 51), obtained from chicken and chicken meats. Out of 627 Enterobacteriaceae, 8.6% of isolates exhibited colistin resistance phenotypically. Among these colistin resistant isolates, 9.3% (n = 37) were isolated from chicken meat, 7.2% (n = 11) from the cloacal swab of chicken and 7.9% (n = 6) from the litter samples. Overall, 12.96% of colistin-resistant isolates were positive with mcr genes, in which mcr-1 and mcr-5 genes were determined in 11.11% and 1.85% of colistin-resistant isolates, respectively. The E. coli isolates obtained from chicken meats, cloacal swabs and litter samples were found positive for mcr-1, and Salmonella spp. originated from the chicken meat sample was observed with mcr-5, whereas no mcr genes were observed in K. pneumoniae strains isolated from any of the collected samples. The other colistin resistance genes, including mcr-2, mcr-3, mcr-4, mcr-6, mcr-7, mcr-8, mcr-9, and mcr-10 were not detected in the studied samples. The mcr-1 and mcr-5 genes were sequenced and found to be 100% identical to the mcr-1 and mcr-5 gene sequences available in the NCBI database. This is the first report of colistin resistance mcr-5 gene in Malaysia which could portend the emergence of mcr-5 harboring bacterial strains for infection. Further studies are needed to characterize the mr-5 harbouring bacteria for the determination of plasmid associated with mcr-5 gene.

Antimicrobial Resistance Profiles and Co-Existence of Multiple Antimicrobial Resistance Genes in mcr-Harbouring Colistin-Resistant Enterobacteriaceae Isolates Recovered from Poultry and Poultry Meats in Malaysia

The co-existence of the colistin resistance (mcr) gene with multiple drug-resistance genes has raised concerns about the possibility of the development of pan-drug-resistant bacteria that will complicate treatment. This study aimed to investigate the antibiotic resistance profiles and co-existence of antibiotic resistance genes among the colistin-resistant Enterobacteriaceae isolates recovered from poultry and poultry meats. The antibiotic susceptibility to various classes of antibiotics was performed using the Kirby-Bauer disk diffusion method and selected antimicrobial resistance genes were detected using PCR in a total of 54 colistin-resistant Enterobacteriaceae isolates including Escherichia coli (E. coli) (n = 32), Salmonella spp. (n = 16) and Klebsiella pneumoniae (K. pneumoniae) (n = 6) isolates. Most of the isolates had multi-drug resistance (MDR), with antibiotic resistance against up to seven classes of antibiotics. All mcr-harbouring, colistin-resistant Enterobacteriaceae isolates showed this MDR (100%) phenotype. The mcr-1 harbouring E. coli isolates were co-harbouring multiple antibiotic resistance genes. The seven most commonly identified resistance genes (^blaTEM, tetA, floR, aac-3-IV, aadA1, fosA, aac(6_)-lb) were detected in an mcr-1-harbouring E. coli isolate recovered from a cloacal swab. The mcr-5 harbouring Salmonella spp. isolate recovered from poultry meats was positive for ^blaTEM, tetA, floR, aac-3-IV, fosA and aac(6_)-lb genes. In conclusion, the colistin-resistant Enterobacteriaceae with mcr genes co-existing multiple clinically important antimicrobial resistance genes in poultry and poultry meats may cause potential future threats to infection treatment choices in humans and animals.

The menace of colistin resistance across globe: Obstacles and opportunities in curbing its spread

Colistin-resistance in bacteria is a big concern for public health, since it is a last resort antibiotic to treat infectious diseases of multidrug resistant and carbapenem resistant Gram-negative pathogens in clinical settings. The emergence of colistin resistance in aquaculture and poultry settings has escalated the risks associated with colistin resistance in environment as well. The staggering number of reports pertaining to the rise of colistin resistance in bacteria from clinical and non-clinical settings is disconcerting. The co-existence of colistin resistant genes with other antibiotic resistant genes introduces new challenges in combatting antimicrobial resistance. Some countries have banned the manufacture, sale and distribution of colistin and its formulations for food producing animals. However, to tackle the issue of antimicrobial resistance, a one health approach initiative, inclusive of human, animal, and environmental health needs to be developed. Herein, we review the recent reports in colistin resistance in bacteria of clinical and non-clinical settings, deliberating on the new findings obtained regarding the development of colistin resistance. This review also discusses the initiatives implemented globally in mitigating colistin resistance, their strength and weakness.

Cefotaxime-, Ciprofloxacin-, and Extensively Drug-Resistant Escherichia coli O157:H7 and O55:H7 in Camel Meat

The present study aimed to explore for the first time the occurrence and the antimicrobial resistance profiles of E. coli O157:H7 and O55:H7 isolates in camel meat in Egypt. Among the 110 camel meat samples examined using standardized microbiological techniques, 10 (9.1%) and 32 (29.1%) were positive for E. coli O157:H7 and E. coli O55:H7, respectively. In total, 24 isolates were verified as E. coli O157:H7, while 102 isolates were confirmed serologically as E. coli O55:H7. Multiplex PCR revealed the existence of eaeA, stx1, stx2, and EHEC-hlyA among E. coli O157:H7 and O55:H7 isolates (n = 126) at various percentages. According to their resistance against 14 antibiotics, 16.7% and 83.3% of O157:H7 isolates and 8.6% and 76.5% of O55:H7 isolates were classified into extensively drug-resistant and multi-drug-resistant, respectively, whereas 29.4% and 22.2% of E. coli isolates were resistant to cefotaxime and ciprofloxacin, respectively. The study results emphasize that camel meat may be a vehicle for multi- and extensively drug-resistant E. coli O157:H7 and O55:H7 strains, indicating a potential threat to public health. Further studies based on the molecular evidence of the antimicrobial resistance genes and enrolling a larger number of samples are recommended for a better understanding of the antimicrobial resistance phenomenon of camel-meat-originating pathogenic E. coli strains.

β-Lactamase Producing Escherichia coli Encoding blaCTX-M and blaCMY Genes in Chicken Carcasses from Egypt

Escherichia coli with multidrug resistance and β-lactamase genes may constitute a great public health hazard due to the potential for their transmission to humans through the food chain. This study determined the prevalence, antibiotic resistance profiles, phylogroups, and β-lactamase genes of E. coli isolates from chicken carcasses marketed in Mansoura, Egypt. Interestingly, E. coli was detected in 98% (98/100) of the chicken carcasses examined, which seemed among the highest contamination rates by E. coli worldwide. From the 425 genetically verified uidA gene-positive E. coli, 85 isolates were further studied for antimicrobial resistance profiles, phylogroups, and β-lactamase genes. Interestingly, 89.41% of E. coli (76/85) strains tested against 24 different antibiotics were multidrug-resistant. Of the examined 85 E. coli isolates, 22 (25.88%) isolates harbored bla_CTX-M and were resistant to ampicillin, cefazoline, and ceftriaxone, while three of them were resistant to ceftazidime besides. Nine (10.59%) E. coli strains harbored AmpC- β-lactamase bla_CMY and were resistant to ampicillin. One isolate co-carried bla_CMY and bla_CTX-M genes, though it was negative for the bla_TEM gene. Of the 35 isolates that harbored either extended-spectrum β-lactamase (ESBL) and/or AmpC β-lactamase genes, six strains (17.14%) were assigned to pathogenic phylogroup F and one to phylogroup E, whereas 28 (80%) isolates belonged to commensal phylogenetic groups.

Evolution and implementation of One Health to control the dissemination of antibiotic-resistant bacteria and resistance genes: A review

Antibiotic resistance is a serious threat to humanity and its environment. Aberrant usage of antibiotics in the human, animal, and environmental sectors, as well as the dissemination of resistant bacteria and resistance genes among these sectors and globally, are all contributing factors. In humans, antibiotics are generally used to treat infections and prevent illnesses. Antibiotic usage in food-producing animals has lately emerged as a major public health concern. These medicines are currently being utilized to prevent and treat infectious diseases and also for its growth-promoting qualities. These methods have resulted in the induction and spread of antibiotic resistant infections from animals to humans. Antibiotics can be introduced into the environment from a variety of sources, including human wastes, veterinary wastes, and livestock husbandry waste. The soil has been recognized as a reservoir of ABR genes, not only because of the presence of a wide and varied range of bacteria capable of producing natural antibiotics but also for the usage of natural manure on crop fields, which may contain ABR genes or antibiotics. Fears about the human health hazards of ABR related to environmental antibiotic residues include the possible threat of modifying the human microbiota and promoting the rise and selection of resistant bacteria, and the possible danger of generating a selection pressure on the environmental microflora resulting in environmental antibiotic resistance. Because of the connectivity of these sectors, antibiotic use, antibiotic residue persistence, and the existence of antibiotic-resistant bacteria in human-animal-environment habitats are all linked to the One Health triangle. The pillars of support including rigorous ABR surveillance among different sectors individually and in combination, and at national and international level, overcoming laboratory resource challenges, and core plan and action execution should be strictly implemented to combat and contain ABR under one health approach. Implementing One Health could help to avoid the emergence and dissemination of antibiotic resistance while also promoting a healthier One World. This review aims to emphasize antibiotic resistance and its regulatory approaches from the perspective of One Health by highlighting the interconnectedness and multi-sectoral nature of the human, animal, and environmental health or ill-health facets.

Investigation of the Phenolic Component Bioavailability Using the In Vitro Digestion/Caco-2 Cell Model, as well as the Antioxidant Activity in Chinese Red Wine

Red wine is a well-known alcoholic beverage, and is known to have phenolic compounds (PCs), which contribute to its antioxidant activity and have other beneficial advantages for human health. The aim of this study was to evaluate the effect of the simulated gastro-intestinal digestion and the Caco-2 transepithelial transport assay on the PCs, bioavailability, and the antioxidant capacity of red wines. The contents of PCs in red wine were significantly reduced during most of the digestion phases. Phenolic acid had the greatest permeability, while the flavonols had the weakest. The bioavailability of PCs ranged from 2.08 to 24.01%. The result of the partial least squares structural equation model showed that the three phenols were positively correlated with the antioxidant activity of red wine. The contribution of anthocyanins was the largest (0.8667).

Molecular Characterization of Extended-Spectrum ß-lactamase Producers, Carbapenemase Producers, Polymyxin-Resistant, and Fosfomycin-Resistant Enterobacterales Among Pigs from Egypt

OBJECTIVES

To perform the first prospective surveillance evaluating the occurrence of genes encoding colistin resistance, fosfomycin resistance, carbapenemase or extended-spectrum ß-lactamases (ESBLs) among Enterobacterial isolates recovered from the gut flora of pigs from Egypt.

METHODS

Between February and April 2020, eighty-one rectal swabs were collected from pigs in a slaughterhouse, Cairo, Egypt. Samples were screened for different resistance mechanisms using SuperPolymyxin, ChromID ESBL, SuperFOS, SuperCarba selective agar plates. Antimicrobial susceptibility testing was performed for all isolates using disk diffusion and broth microdilution techniques. PCR screening was performed for ESBLs, carbapenemases, mcr, and fosA genes. Mating-out assays, multilocus sequence typing analysis and plasmid typing were also performed.

RESULTS

A high prevalence of ESBLs, carbapenemases, fosfomycin and colistin resistance genes was evidenced among those isolates. The predominant ESBL identified was bla_CTX-M-15, followed by bla_CTX-M-9. We also identified bla_NDM-5 and bla_OXA-244. fosA3, fosA4, and fosA6 were identified in E. coli isolates. In addition, eleven MCR-1 producers were recovered. Notably, co-occurrence of ESBL genes and mcr or fosA genes was observed. MLST analysis revealed a high clonal diversity, ruling out the dissemination of one major clone. IncFIB-type was predominantly present among ESBL- and FosA-producers. The bla_NDM-5 gene was carried on an IncX4-type, although the bla_OXA-244 gene was chromosomally located. The mcr-1 gene was carried on a diversity of plasmids (IncI2, IncX4, and IncHI2).

CONCLUSIONS

These results raise serious public health concerns as Egyptian pig meat could serve as a reservoir for the antimicrobial resistance genes (ARGs) leading to worldwide dissemination.

Isolation, identification, and antibiogram studies of Escherichia coli from ready-to-eat foods in Mymensingh, Bangladesh

Background and Aim

Ready-to-eat (RTE) foods are widely used at home, restaurants, and during festivals in Bangladesh. So it is very important to investigate possible microbial contamination in RTE foods. Therefore, this study aimed to determine the total coliform count (TCC), isolate, identify, and characterize the Escherichia coli in RTE foods. The antimicrobial sensitivity of E. coli obtained from RTE foods was also performed using 12 commonly used antibiotics.

Materials and Methods

A total of 100 RTE food samples were collected aseptically and comprised of ten samples each: Burger, pizza, sandwich, chicken roll, chicken meat loaf, chicken fry, salad vegetable, ice-cream, yogurt, and milkshake sold in Mymensingh City. Samples were inoculated onto Eosin methylene blue agar and incubated at 37°C for 24 h. Isolation and identification of bacteria were performed based on cultural, staining, and biochemical properties, followed by a polymerase chain reaction.

Results

The TCC in Chicken meat loaf, burger, pizza, sandwich, salad vegetable ice-cream, and yogurt samples were 3.57 ± 0.96, 3.69 ± 0.08, 3.50 ± 0.60, 2.60 ± 0.20, 4.09 ± 0.29, 4.44 ± 0.25, and 3.14 ± 0.30 mean log colony-forming units ± standard deviation/mL, respectively. The study found a higher prevalence of E. coli in RTE salad vegetable products than in RTE meat and milk products. Forty percent of the mixed vegetable salad samples showed positive results for E. coli. Whereas E. coli prevalence in RTE meat and milk products was 20% and 16.7%, respectively. All the 21 isolates were subjected to antibiotic susceptibility test against 12 different antibiotics. It was observed that 46.1% were susceptible, 16.6% were intermediate, 46.1% were resistant, and 47.6% were multidrug-resistant (MDR) among seven different antibiotic classes. E. coli isolates were resistant to cephalexin, ceftazidime, oxytetracycline, and ampicillin and sensitive to gentamycin, followed by kanamycin, ceftriaxone, colistin, and enrofloxacin.

Conclusion

The study revealed that RTE foods are a serious issue from a public health point of view. To achieve a safer level of E. coli in RTE foods sold for human consumption, public food outlets must improve hygienic and good production procedures. Moreover, MDR E. coli in these foods pose serious public health threats.

Prevalence and characteristics of the mcr-1 gene in retail meat samples in Zhejiang Province, China

Considering the serious threat to food safety and public health posed by pathogens with colistin resistance, colistin was banned as a growth promoter in 2017 in China. In recent years, the resistance rate of Escherichia coli isolated from animal intestines or feces to colistin has decreased. However, the prevalence and characteristics of the mcr-1 gene in retail meat have not been well explored. Herein, 106 mcr-1-negative and 16 mcr-1-positive E. coli isolates were randomly recovered from 120 retail meat samples and screened using colistin. The 106 E. coli isolates showed maximum resistance to sulfafurazole (73.58%) and tetracycline (62.26%) but susceptibility to colistin (0.00%). All 16 mcr-1-positive E. coli isolates showed resistance to colistin, were extended spectrum beta-lactamase (ESBL)-positive and exhibited complex multidrug resistance (MDR). For these 16 isolates, 17 plasmid replicons and 42 antibiotic resistance genes were identified, and at least 7 antibiotic resistance genes were found in each isolate. Acquired disinfectant resistance genes were identified in 75.00% (12/16) of the isolates. Furthermore, comparative genomic and phylogenetic analysis results indicated that these 16 mcr-1-positive E. coli isolates and the most prevalent mcr-1-harboring IncI2 plasmid in this study were closely related to other previously reported mcr-1-positive E. coli isolates and the IncI2 plasmid, respectively, showing their wide distribution. Taken together, our findings showed that retail meat products were a crucial reservoir of mcr-1 during the colistin ban period and should be continuously monitored.

Antibiotic resistance and ESBL production in Escherichia coli from various sources in Aba metropolis, Nigeria

BACKGROUND

The increase in multidrug resistance (MDR) among pathogenic bacteria responsible for infectious diseases has led to lack of effectiveness of some antibiotics. The ability of Escherichia coli to harbor resistant genes has made the treatment of infections a major challenge. This study was carried out to assess antibiotic resistance and extended-spectrum beta-lactamase (ESBL) production of E. coli from various sources in Aba metropolis, Nigeria.

RESULTS

From a total of 350 samples collected from clinical and non-clinical sources, 137 were presumptively identified as E. coli by standard phenotypic methods and 83 were confirmed as E. coli by the detection of E. coli specific 16S rRNA gene fragments. The majority of these isolates (52, 62.7%) were from non-clinical sources. The clinical isolates, however, exhibited a higher level of resistance against 62.5% of tested antibiotics. Both group of isolates exhibited similar levels (58.1% vs 53.9%) of MDR, though. A low rate of ESBL production was observed (1.2%) following phenotypic detection of ESBL-producing abilities using the double-disc synergy test. An assessment of the presence of three beta-lactamase gene genotypes (bla_TEM, bla_SHV and bla_CTX-M) revealed that none of the three predominant ESBL genotypes was identified in this study.

CONCLUSIONS

This study reports high levels of antibiotic resistance in both clinical and non-clinical E. coli isolates. Though higher rates of resistance were observed among the non-clinical isolates, both group of organisms had similar levels of MDR. Strikingly, however, was the low level of ESBL producers detected in this study and the absence of the three main genotypes associated with ESBL production in this study.

Is Africa ready for mobile colistin resistance threat?

Antimicrobial resistance is a growing public health problem and a threat to effective treatment and prevention of an array of infections caused by bacteria. Africa is already faced with many socio-economic and health crises. Many countries in Africa can seldom boast of a standardized health care facility comparable to those in developed countries. Yet, the non-therapeutic use of COL has been banned in developed countries. However, in Africa, except for South Africa, COL is an over-the-counter (OTC) medication sold and dispensed by non-professionals/without a veterinarian's supervision. The ban of non-therapeutic COL in developed countries has proven to reduce the development of mobile colistin resistance (MCR) in humans and animals. The unregulated use of COL has been proven to select pathogenic and commensal bacteria resistance. A transmissible plasmid-mediated colistin determinant, mobile COL resistance (mcr) gene, which is rapidly transferred/acquired horizontally or laterally intra/inter-species/genera, has been reported. A highly promiscuous mobile genetic element like plasmids containing transposons, insertion sequences, and integrons aid the carriage/rapid transfer and acquisition of these mcr genes. Hence, we highlight the danger posed by escalating colistin (COL) resistance in the continent and the impetus to halt the indiscriminate and non-therapeutic use of COL to protect public health.

Emergence of Multidrug-Resistant Escherichia coli Producing CTX-M, MCR-1, and FosA in Retail Food From Egypt

In this study, multidrug-resistant (MDR) Escherichia coli isolates from retail food and humans assigned into similar Multilocus Sequence Types (MLST) were analyzed using whole genome sequencing (WGS). In silico analysis of assembled sequences revealed the existence of multiple resistance genes among the examined E. coli isolates. Of the six CTX-M-producing isolates from retail food, bla _CTX-M-14 was the prevalent variant identified (83.3%, 5/6). Two plasmid-mediated fosfomycin resistance genes, fosA3, and fosA4, were detected from retail food isolates (one each from chicken and beef), where fosA4 was identified in the chicken isolate 82CH that also carried the colistin resistance gene mcr-1. The bla _CTX-M-14 and fosA genes in retail food isolates were located adjacent to insertion sequences ISEcp1 and IS26, respectively. Sequence analysis of the reconstructed mcr-1 plasmid (p82CH) showed 96-97% identity to mcr-1-carrying IncI2 plasmids previously identified in human and food E. coli isolates from Egypt. Hierarchical clustering of core genome MLST (HierCC) revealed clustering of chicken isolate 82CH, co-harboring mcr-1 and fosA4 genes, with a chicken E. coli isolate from China at the HC200 level (≤200 core genome allelic differences). As E. coli co-harboring mcr-1 and fosA4 genes has only been recently reported, this study shows rapid spread of this genotype that shares similar genetic structures with regional and international E. coli lineages originating from both humans and food animals. Adopting WGS-based surveillance system is warranted to facilitate monitoring the international spread of MDR pathogens.

Prevalence and Molecular Characterization of Antimicrobial-Resistant Escherichia coli in Pig Farms, Slaughterhouses, and Terminal Markets in Henan Province of China

Escherichia coli is an important foodborne pathogen and also plays key roles in dissemination of antimicrobial resistance genes (ARGs). However, current data on the prevalence of antimicrobial-resistant E. coli at different nodes of the pork supplying chain are still limited. Herein, we investigated drug-resistant phenotypes and molecular characteristics of E. coli strains isolated from different pig farms, slaughterhouses, and terminal markets in the Henan Province of China. A total of 191 (70.74%), 140 (35.09%), and 77 (30.20%) E. coli strains were isolated from 270, 399, and 255 samples collected from pig farms, slaughterhouses, and retailing markets, respectively. Antimicrobial susceptibility testing revealed that these 408 strains showed severe antimicrobial resistance profiles. Approximately 93.19% (178/191), 66.43% (93/140), and 67.53% (52/77) of the isolates from farms, slaughterhouses, and terminal markets were resistant to three of the nine antibiotic classes tested, respectively. Multilocus sequence typing showed that sequence types (STs) 10 and ST101 were commonly identified among the isolates from farms, slaughterhouses, and terminal markets. Isolates belonging to these two STs carried multiple ARGs, conferring resistance to the antibiotics tested. Two important ARGs with great public health concerns (mcr-1 and bla_NDM-1) were found from these two STs. Isolates belonging to these two STs also carried several virulence factor-encoding genes, including astA, tsh, and traT, which might contribute to the pathogenesis of these isolates. The wide prevalence and distribution of these two STs in different nodes of pork supplying chain might represent a big public health threat and should receive more attention.

Review on the occurrence of the mcr-1 gene causing colistin resistance in cow's milk and dairy products

Both livestock farmers and the clinic use significant amount of antibiotics worldwide, in many cases the same kind. Antibiotic resistance is not a new phenomenon, however, it is a matter of concern that resistance genes (mcr - Mobilized Colistin Resistance - genes) that render last-resort drugs (Colistin) ineffective, have already evolved. Nowadays, there is a significant consumption of milk and dairy products, which, if not treated properly, can contain bacteria (mainly Gram-negative bacteria). We collected articles and reviews in which Gram-negative bacteria carrying the mcr-1 gene have been detected in milk, dairy products, or cattle. Reports have shown that although the incidence is still low, unfortunately the gene has been detected in some dairy products on almost every continent. In the interest of our health, the use of colistin in livestock farming must be banned as soon as possible, and new treatments should be applied so that we can continue to have a chance in fighting multidrug-resistant bacteria in human medicine.

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.

Prevalence and Loads of Fecal Pollution Indicators and the Antibiotic Resistance Phenotypes of Escherichia coli in Raw Minced Beef in Lebanon

Meat is an important source of high biological value proteins as well as many vitamins and minerals. In Lebanon, beef meats, including raw minced beef, are among the most consumed of the meat products. However, minced beef meat can also be an important source of foodborne illnesses. This is of a major concern, because food safety in Lebanon suffers from well-documented challenges. Consequently, the prevalence and loads of fecal coliforms and Escherichia coli were quantified to assess the microbiological acceptability of minced beef meat in Lebanon. Additionally, antibiotic resistance phenotypes of the E. coli were determined in response to concerns about the emergence of resistance in food matrices in Lebanon. A total of 50 meat samples and 120 E. coli isolates were analyzed. Results showed that 98% and 76% of meat samples harbored fecal coliforms and E. coli above the microbial acceptance level, respectively. All E. coli were resistant to at least one antibiotic, while 35% of the isolates were multidrug-resistant (MDR). The results suggest that Lebanon needs to (1) update food safety systems to track and reduce the levels of potential contamination in important foods and (2) implement programs to control the proliferation of antimicrobial resistance in food systems.