Dissemination of Extended-Spectrum β-Lactamase- and AmpC β-Lactamase-Producing Escherichia coli within the Food Distribution System of Ho Chi Minh City, Vietnam

Contamination of retail market meat with extended-spectrum beta-lactamase genes in Vietnam

The contamination of retail meat with antibiotic-resistant bacteria poses a substantial public health risk because of the potential spread of these bacteria within communities. The contamination of retail meat with extended-spectrum beta-lactamase (ESBL)-producing bacteria was investigated in four cities in Vietnam using real-time PCR, employing ESBL marker genes. This method provides a more comprehensive assessment of ESBL-producing bacterial contamination in meat samples than culture-based methods because it directly detects resistance genes from the extracted sample DNA. Retail meats in Vietnam were substantially contaminated with ESBL genes [54 % (n = 46) and 48 % (n = 49) of chicken and pork samples, respectively]. No significant differences in ESBL gene detection rates were observed between chicken and pork. The most frequently detected ESBL gene was blaTEM, followed by blaSHV, whereas blaCTX-M was found in only 4-8 % of the samples. Ho Chi Minh City showed significantly higher contamination rates for both chicken and pork than those in other cities. ESBL-producing Escherichia coli strains were isolated from contaminated meat samples and genomically analyzed. All isolated strains carried blaCTX-M, with some harboring blaTEM, whereas blaSHV was not detected. Although IncFIB plasmids were prevalent among the ESBL-producing E. coli strains, the variability in resistance gene profiles suggested that the endemic spread of specific resistance gene-carrying plasmids was unlikely. Overall, these findings highlight the effectiveness of the ESBL gene detection method and the high levels of ESBL-producing E. coli in retail meat.

AmpC β-lactamases detected in Southeast Asian Escherichia coli and Klebsiella pneumoniae

Objectives

AmpC β-lactamases are neglected compared with ESBL as a cause of third-generation cephalosporin (3GC) resistance in Enterobacterales in low- and middle-income countries and the burden is unknown. The aim of this study was to investigate the presence of AmpC β-lactamase-producing Escherichia coli and Klebsiella pneumoniae in clinical specimens from three clinical research laboratories in Southeast Asia.

Methods

Stored clinical isolates of E. coli and K. pneumoniae resistant to ceftriaxone or ceftazidime or cefpodoxime and ESBL confirmation test negative were screened using MASTDISCS AmpC, ESBL and Carbapenemase Detection Set-D72C. Short-read WGS was performed to identify ampC genes.

Results

Of 126 isolates collected between 2010 and 2020, 31 (24.6%) and 16 (12.7%) were phenotypically AmpC and inducible AmpC positive by MASTDISCS testing, respectively. All inducible AmpC isolates were ceftriaxone susceptible and 97.7% of AmpC/inducible AmpC isolates tested against cefoxitin were resistant. Through WGS, 17 and eight different STs were detected for the AmpC/inducible AmpC E. coli and K. pneumoniae isolates, respectively. Twelve different β-lactamase resistance genes were detected, with bla CMY-2 most commonly in AmpC-positive isolates (20/31; 64.5%; 15 chromosomal, five plasmid). All inducible AmpC-positive isolates had the bla DHA-1 gene (seven chromosomal, nine plasmid).

Conclusions

Though uncommon, AmpC and inducible AmpC β-lactamases in E. coli and K. pneumoniae are an important cause of infection in Southeast Asia. With current testing methods, these infections may be going undetected, resulting in patients receiving suboptimal treatment.

Whole-Genome Sequence Analysis of Antibiotic Resistance, Virulence, and Plasmid Dynamics in Multidrug-Resistant E. coli Isolates from Imported Shrimp

We analyzed antimicrobial resistance and virulence traits in multidrug-resistant (MDR) E. coli isolates obtained from imported shrimp using whole-genome sequences (WGSs). Antibiotic resistance profiles were determined phenotypically. WGSs identified key characteristics, including their multilocus sequence type (MLST), serotype, virulence factors, antibiotic resistance genes, and mobile elements. Most of the isolates exhibited resistance to gentamicin, streptomycin, ampicillin, chloramphenicol, nalidixic acid, ciprofloxacin, tetracycline, and trimethoprim/sulfamethoxazole. Multilocus sequence type (MLST), serotype, average nucleotide identity (ANI), and pangenome analysis showed high genomic similarity among isolates, except for EC15 and ECV01. The EC119 plasmid contained a variety of efflux pump genes, including those encoding the acid resistance transcriptional activators (gadE, gadW, and gadX), resistance-nodulation-division-type efflux pumps (mdtE and mdtF), and a metabolite, H1 symporter (MHS) family major facilitator superfamily transporter (MNZ41_23075). Virulence genes displayed diversity, particularly EC15, whose plasmids carried genes for adherence (faeA and faeC-I), invasion (ipaH and virB), and capsule (caf1A and caf1M). This comprehensive analysis illuminates antimicrobial resistance, virulence, and plasmid dynamics in E. coli from imported shrimp and has profound implications for public health, emphasizing the need for continued surveillance and research into the evolution of these important bacterial pathogens.

Prevalence and Antimicrobial Resistance of Escherichia coli Isolates from Chicken Meat in Romania

The current study was conducted in order to analyze the prevalence of Escherichia coli (E. coli) in samples of chicken meat (100 chicken meat samples), as well as to evaluate the antimicrobial susceptibility of these isolates. A total of 30 samples were positive for E. coli among the collected chicken samples. Most isolates proved to be highly resistant to tetracycline (80%), ampicillin (80%), sulfamethoxazole (73.33%), chloramphenicol (70%) and nalidixic acid (60%). Strong resistance to ciprofloxacin (56.66%), trimethoprim (50%), cefotaxime (46.66%), ceftazidime (43.33%) and gentamicin (40%) was also observed. Notably, one E. coli strain also proved to be resistant to colistin. The antimicrobial resistance determinants detected among the E. coli isolates recovered in our study were consistent with their resistance phenotypes. Most of the isolates harbored the tetA (53.33%), tetB (46.66%), blaTEM (36.66%) and sul1 (26.66%) genes, but also aadA1 (23.33%), blaCTX (16.66%), blaOXA (16.66%), qnrA (16.66%) and aac (10%). In conclusion, to the best of our knowledge, this is among the first studies analyzing the prevalence and antimicrobial resistance of E. coli strains isolated from chicken meat in Romania and probably the first study reporting colistin resistance in E. coli isolates recovered from food sources in our country.

Antibiotic Resistance Profiles and Molecular Characteristics of blaCMY-2-Carrying Salmonella enterica Serovar Albany Isolated from Chickens During 2013-2020 in South Korea

The production of β-lactamase by nontyphoidal Salmonella has become a public health issue throughout the world. In this study, we aimed to investigate the antimicrobial resistance profiles and molecular characteristics of β-lactamase-producing Salmonella enterica serovar Albany isolates. A total of 434 Salmonella Albany were obtained from feces and carcasses of healthy and diseased food-producing animals [cattle (n = 2), pigs (n = 3), chickens (n = 391), and ducks (n = 38)] during 2013-2020. Among the 434 Salmonella Albany isolates, 3.7% showed resistance to cefoxitin, and all the cefoxitin-resistant isolates were obtained from chickens. Moreover, Salmonella Albany isolates demonstrated high resistance to nalidixic acid (99.3%), trimethoprim/sulfamethoxazole (97.9%), ampicillin (86.6%), chloramphenicol (86.6%), and tetracycline (85.7%), as well as higher rates of multidrug resistance were detected in cefoxitin-resistant isolates compared to cefoxitin-susceptible isolates. All cefoxitin-resistant isolates harbored CMY-2-type β-lactamase and belonged to seven different pulsotypes, with type IV-b (43.75%) and IV-a (25%) making up the majority. In addition, genes encoding cefoxitin resistant of all blaCMY-2-harboring Salmonella Albany isolates were horizontally transmitted to a recipient Escherichia coli J53 by conjugation. Furthermore, 93.75% (15/16) of conjugative plasmids harboring blaCMY-2 genes belong to ST12/CC12-IncI1. Genetic characteristics of transmitted blaCMY-2 genes were associated with ISEcp1, which can play an essential role in the effective mobilization and expression of these genes. Salmonella Albany containing blaCMY-2 in chickens can potentially be transferred to humans. Therefore, it is necessary to restrict antibiotic use and conduct continuous monitoring and analysis of resistant bacteria in the poultry industry.

Antimicrobial resistance and biofilm formation of Escherichia coli in a Vietnamese Pangasius fish processing facility

This study aimed to investigate the occurrence, antibiotic resistance, and biofilm formation of Escherichia coli in the Vietnamese Pangasius fish processing facility. Among 144 samples including Pangasius fish, wash water, food contact surfaces, and personnel gloves, 18 E. coli isolates was detected and characterized. The E. coli was detected most frequently in wash water samples (22%, 8/36), followed by Pangasius fish (18%, 8/45). According to the antibiotic susceptibility test by the disc diffusion method, isolates showed the highest resistance against sulfamethoxazole/trimethoprim (45%), followed by tetracycline (39%), whereas all the E. coli isolates were susceptible to meropenem and fosfomycin. Notably, 39% of the isolates (7/18) were found to be multidrug resistant while no E. coli isolates were confirmed as extended-spectrum β-lactamase producers by the double-disk synergy test. The potency to form biofilm on the polystyrene surface of E. coli isolates indicated that 44% of the isolates (8/18) were classified as weak, 39% (7/18) as moderate, and 17% (3/18) as strong biofilm formers. Interestingly, multidrug resistant E. coli isolates were observed in moderate and strong biofilm producers. Additionally, either slightly acidic hypochlorous water with 40 mg/L of available chlorine or sodium hypochlorite with 100 mg/L of available chlorine exhibited a significant reduction in biofilm mass and biofilm cells of E. coli isolates. This study may provide helpful information about the actual state of E. coli isolates for effective control in the fish processing plant.

Prevalence and Types of Extended-Spectrum β-Lactamase-Producing Bacteria in Retail Seafood

Objectives: To assess prevalence and types of extended-spectrum β-lactamase (ESBL)-producing bacteria in retail seafood. Methods: A literature review was completed according to international guidelines for systematic reviews, except for being performed by a single reviewer. Kruskal-Wallis and Dunn tests were used to determine statistical differences between continents or seafood types. Results: Among 12,277 hits, 42 publications from 2011 to 2023 were deemed relevant to the review's objectives. The median prevalence of ESBL-contaminated products was 19.4%. A significantly lower prevalence was observed in Europe (p = 0.006) and Africa (p = 0.004) compared to Asia. Amongst the 2053 isolates analyzed in the selected studies, 44.8% were ESBL-positive. The predominant type was CTX-M (93.6%), followed by TEM (6.7%) and SHV (5.0%). Only 32.6% and 18.5% of the CTX-M-positive isolates were typed to group and gene level, respectively. While group 1 (60.2%) was prevalent over group 9 (39.8%) among Enterobacterales, the opposite trend was observed in Vibrio spp. (60.0% vs. 40.0%). Information at gene level was limited to Enterobacterales, where CTX-M-15 was the most prevalent (79.2%). Conclusions: On average, one in five seafood products sold at retail globally is contaminated with ESBL-producing Enterobacterales of clinical relevance. Our findings highlight a potential risk for consumers of raw seafood, especially in Asia.

Zoonotic sources and the spread of antimicrobial resistance from the perspective of low and middle-income countries

BACKGROUND

Antimicrobial resistance is an increasing challenge in low and middle-income countries as it is widespread in these countries and is linked to an increased mortality. Apart from human and environmental factors, animal-related drivers of antimicrobial resistance in low- and middle-income countries have special features that differ from high-income countries. The aim of this narrative review is to address the zoonotic sources and the spread of antimicrobial resistance from the perspective of low- and middle-income countries.

MAIN BODY

Contamination with extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli is highest in poultry (Africa: 8.9-60%, Asia: 53-93%) and there is a risk to import ESBL-producing E. coli through poultry meat in Africa. In aquacultures, the proportion of ESBL-producers among E. coli can be high (27%) but the overall low quality of published studies limit the general conclusion on the impact of aquacultures on human health. ESBL-producing E. coli colonization of wildlife is 1-9% in bats or 2.5-63% birds. Since most of them are migratory animals, they can disperse antimicrobial resistant bacteria over large distances. So-called 'filth flies' are a relevant vector not only of enteric pathogens but also of antimicrobial resistant bacteria in settings where sanitary systems are poor. In Africa, up to 72.5% of 'filth flies' are colonized with ESBL-producing E. coli, mostly conferred by CTX-M (24.4-100%). While methicillin-resistant Staphylococcus aureus plays a minor role in livestock in Africa, it is frequently found in South America in poultry (27%) or pork (37.5-56.5%) but less common in Asia (poultry: 3%, pork: 1-16%).

CONCLUSIONS

Interventions to contain the spread of AMR should be tailored to the needs of low- and middle-income countries. These comprise capacity building of diagnostic facilities, surveillance, infection prevention and control in small-scale farming.

Common presence of plasmid encoding blaCTX-M-55 in extended-spectrum β-lactamase-producing Salmonella enterica and Escherichia coli isolates from the same edible river fish

The transmission of potentially life-threatening plasmid-mediated antibiotic-resistant bacteria poses a major threat to public health. This study aimed to determine the presence of commonly observed plasmids encoding plasmid-mediated antibiotic-resistance genes in Salmonella and Escherichia coli isolates from fishery products. Eighty river fishes were purchased from retail stores and supermarkets in Vietnam. Only Salmonella-positive fishes were used for antibiotic-resistant E. coli isolation. Salmonella serotyping was performed using Salmonella antisera. Isolated bacterial DNA was extracted, and antibiotic susceptibility, resistance genes, and replicon typing were determined. Our results showed that Salmonella was isolated from 12.5% (10/80) of the river fishes. Cefotaxime-resistant Salmonella was isolated from 3.8% (3/80) of the fishes and colistin-resistant Salmonella from 1.3% (1/80) . Salmonella serotyping revealed Potsdam, Schwarzengrund, Bardo/Newport, Give, Infantis, Kentucky, and Typhimurium. Multiplex polymerase chain reaction revealed the presence of extended-spectrum β-lactamase-related genes blaCTX-M-55 and blaCTX-M-65 and the colistin resistance gene mcr-1. To date, no study has reported an antibiotic-resistance plasmid present in multiple bacteria collected from the same food. Thus, horizontal transmission of antibiotic-resistance plasmids may occur at the food level.

Evaluation of Retail Meat as a Source of ESBL Escherichia coli in Tamaulipas, Mexico

In recent decades, the appearance of a group of strains resistant to most β-lactam antibiotics, called extended-spectrum β-lactamases (ESBLs), has greatly impacted the public health sector. The present work aimed to identify the prevalence of ESBL-producing Escherichia coli strains in retail meat from northeast Tamaulipas. A total of 228 meat samples were obtained from 76 different stores. A prevalence of E. coli ESBL of 6.5% (15/228) was detected. All (15/15) of the ESBL strains were multiresistant. Altogether, 40% (6/15) of the strains showed the presence of class 1 integrons. The isolates identified with bla_CTX-M (20%) also showed co-resistance with the tet (A and B), str (A and B), and sul (2 and 3) genes. A total of 20% of the strains belonged to the B2 and D phylogroups, which are considered pathogenic groups. None of the ESBL-positive strains contained any of the virulence gene factors tested. The presence of ESBL-producing E. coli strains in meat indicates a potential risk to the consumer. Although most of these strains were classified as commensals, they were found to serve as reservoirs of multiresistance to antimicrobials and, therefore, are potential routes of dispersion of this resistance to other bacteria.

Urinary tract virulence genes in extended-spectrum beta-lactamase E. coli from dairy cows, beef cattle, and small ruminants

Extended-spectrum β-lactamase Escherichia coli is an important cause of urinary tract infections in humans. ESBL producers E. coli were reported in food-producing animals, but no previous study reported the virulence potential of these isolates. Thus, this study determined the virulence potential of ESBL producers E. coli isolates from 518 beef feces, 610 dairy cow feces, 305 dairy cow milk, 503 sheep milk and 445 goat milk samples. A total of 278 isolates; specifically, 130 from beef feces, 39 from the cow's feces, 42 from cow's milk, 44 from sheep milk and 23 from goats' milk were isolated and then tested for 14 virulence genes by polymerase chain reaction. After that, the correlation of virulence genes presence among the isolates was determined statistically. Overall, 97% of the isolates carried fimH, 39% carried iroN _{E. coli} and 32% carried papC. The kpsMT K1, cnf1, papAH, papG allele II & III, papG allele II, and kpsMT II were carried by 6 to 23% of the isolates, while less than 6% of the isolates carried papG allele III, papG allele I, Univcnf, iutA and hlyA. About 68.2% of the isolates carried two or more virulence genes and 41.8% carried three or more. Moreover, the isolates had 71 different profiles of virulence genes, where the most common profiles were fimH alone (86 isolate), fimH + iroN _{E. coli} (35 isolate), fimH + papC (20 isolate), and fimH + papC + iroN _{E. coli} (13 isolate). The adhesion, capsule synthesis and toxins secretion genes were significantly associated (p ˂ 0.01) with each other. These results call for awareness about the risk of food animals as reservoirs of ESBL uropathogenic E. coli that would threaten public health and limits the treatment options for urinary tract infections.

Prevalence and Antimicrobial Resistance of Escherichia coli, Salmonella and Vibrio Derived from Farm-Raised Red Hybrid Tilapia (Oreochromis spp.) and Asian Sea Bass (Lates calcarifer, Bloch 1970) on the West Coast of Peninsular Malaysia

Antibiotics are widely used in intensive fish farming, which in turn increases the emergence of antimicrobial-resistant (AMR) bacteria in the aquatic environment. The current study investigates the prevalence and determines the antimicrobial susceptibility of E. coli, Salmonella, and Vibrio in farmed fishes on the west coast of Peninsular Malaysia. Over a period of 12 months, 32 aquaculture farms from the Malaysian states of Selangor, Negeri Sembilan, Melaka, and Perak were sampled. Both E. coli and Salmonella were highly resistant to erythromycin, ampicillin, tetracycline, and trimethoprim, while Vibrio was highly resistant to ampicillin and streptomycin. Resistance to the antibiotics listed as the highest priority and critically important for human therapy, such as colistin in E. coli (18.1%) and Salmonella (20%) in fish, is a growing public health concern. The multi-drug resistance (MDR) levels of E. coli and Salmonella in tilapia were 46.5% and 77.8%, respectively. Meanwhile, the MDR levels of E. coli, Salmonella, V. parahaemolyticus, V. vulnificus and V. cholerae in Asian seabass were 34%, 100%, 21.6%, 8.3% and 16.7%, respectively. Our findings provide much-needed information on AMR in aquaculture settings that can be used to tailor better strategies for the use of antibiotics in aquaculture production at the local and regional levels.

Abundance of colistin-resistant Escherichia coli harbouring mcr-1 and extended-spectrum β-lactamase-producing E. coli co-harbouring blaCTX-M-55 or -65 with blaTEM isolates from chicken meat in Vietnam

Although the spread of plasmid-mediated antibiotic-resistant bacteria is a public health concern, food contamination with plasmid-mediated antibiotic-resistant Escherichia coli in Vietnam has not been well investigated. This study aimed to describe the prevalence of colistin-resistant, carbapenem-resistant, and endemic bla_CTX-M in extended-spectrum β-lactamase (ESBL) producing E. coli isolates. Colistin and carbapenem-resistant ESBL-producing E. coli were isolated from chickens in Vietnam and Japan. Colistin-resistant and AmpC/ESBL-producing E. coli (52% and 93%, respectively) were detected in chickens from Vietnam, in comparison to 52.7%, AmpC/ESBL-producing E. coli found in chicken from Japan. Carbapenem-resistant E. coli has not been isolated in Vietnam and Japan. Genotyping revealed that colistin-resistant E. coli harboured mcr-1, and most of the AmpC/ESBL-related genes were bla_CTX-M-55 and bla_CTX-M-65 together with bla_TEM in Vietnamese chickens and bla_CMY-2 in Japanese chickens. Multi-drug resistance analysis showed that ESBL-producing E. coli isolates had greater resistance to quinolones, streptomycin, and chloramphenicol than colistin-resistant E. coli isolates from Vietnam, suggesting the selection of multiple antibiotic resistance genes in ESBL-producing E. coli. In conclusion, colistin-resistant E. coli was detected in approximately half of the chicken samples, the majority of which harboured mcr-1. The high prevalence of ESBL-producing E. coli has remained constant in the last 5 years. The predominant bla_CTX-M in ESBL-producing E. coli was bla_CTX-M-55 or bla_CTX-M-65, with the coexistence of bla_TEM in Vietnam. These results can be implemented in monitoring systems to overcome the development of antimicrobial resistance.

Occurrence, Antimicrobial Resistance Profile, and Characterization of Extended-spectrum β-Lactamase-Producing Escherichia coli Isolates from Minced Meat at Local Markets in Thailand

Extended-spectrum β-lactamase (ESBL)-producing Escherichia coli exhibits strong multidrug resistance (MDR) to ampicillin and third-generation cephalosporins. This study examined the occurrence, antimicrobial susceptibility, and molecular genetic features of ESBL-producing E. coli isolates from three commonly consumed minced meat varieties, namely pork, chicken, and beef. In total, 150 samples were collected from 10 local markets in Thailand. ESBL-producing E. coli was identified in 78 samples (52%), and minced chicken meat was most contaminated (79.17%). The isolates exhibited potential susceptibility to amikacin (96.16%) and carbapenems (91-95%). However, ESBL-producing E. coli displayed strong resistance to ampicillin and cefpodoxime (100%) and high MDR to 3-5 antibiotic classes (94.87%). Most presumptive ESBL producers harbored ESBL resistance genes (97.44%), most commonly bla_TEM (78.21%). Indeed, our results demonstrated that raw minced meat has a high occurrence of ESBL-producing E. coli harboring ESBL resistance genes, highlighting the importance of implementation of sanitary handling practices to reduce microbial contamination in commercial meat as well as the need for consumer education on safe handling and cooking of meat products.

Genomic insights into the circulation of pandemic fluoroquinolone-resistant extra-intestinal pathogenic Escherichia coli ST1193 in Vietnam

Extra-intestinal pathogenic Escherichia coli (ExPEC) ST1193, a globally emergent fluoroquinolone-resistant clone, has become an important cause of bloodstream infections (BSIs) associated with significant morbidity and mortality. Previous studies have reported the emergence of fluoroquinolone-resistant ExPEC ST1193 in Vietnam; however, limited data exist regarding the genetic structure, antimicrobial resistance (AMR) determinants and transmission dynamics of this pandemic clone. Here, we performed genomic and phylogenetic analyses of 46 ST1193 isolates obtained from BSIs and healthy individuals in Ho Chi Minh City, Vietnam, to investigate the pathogen population structure, molecular mechanisms of AMR and potential transmission patterns. We further examined the phylogenetic structure of ST1193 isolates in a global context. We found that the endemic E. coli ST1193 population was heterogeneous and highly dynamic, largely driven by multiple strain importations. Several well-supported phylogenetic clusters (C1-C6) were identified and associated with distinct bla _CTX-M variants, including bla _CTXM-27 (C1-C3, C5), bla _CTXM-55 (C4) and bla _CTXM-15 (C6). Most ST1193 isolates were multidrug-resistant and carried an extensive array of AMR genes. ST1193 isolates also exhibited the ability to acquire further resistance while circulating in Vietnam. There were phylogenetic links between ST1193 isolates from BSIs and healthy individuals, suggesting these organisms may both establish long-term colonization in the human intestinal tract and induce infections. Our study uncovers factors shaping the population structure and transmission dynamics of multidrug-resistant ST1193 in Vietnam, and highlights the urgent need for local One Health genomic surveillance to capture new emerging ExPEC clones and to better understand the origins and transmission patterns of these pathogens.

Antibiotic Resistant Enterobacteriaceae in Milk Alternatives

The consumption of non-dairy milk is on the rise due to health benefits. Although there is increasing inclination towards milk alternatives (MA), there is limited data on antibiotic resistant bacteria in these substitutes. The aim of this study was to investigate antimicrobial resistance of bacteria isolated from MA. A total of 138 extracts from almonds (n = 63), cashew nuts (n = 36), and soybeans (n = 39) were analyzed for Enterobacteriaceae. The identification of the bacteria was based on biochemical and PCR methods. Antibiotic sensitivity was determined by using the Kirby-Bauer disk diffusion technique. Overall, 31% (43 of 138) of extracts were positive for Enterobacteriaceae. Ten bacterial species were identified, of which Enterobacter cloacae (42.7%) and Enterobacter cancerogenus (35.4%) were the most predominant species (p < 0.05). Antibiotic resistance was exhibited to vancomycin (88.3%), novobiocin (83.8%), erythromycin (81.1%), which was significantly higher (p < 0.05) than in tetracycline (59.5%), cefpodoxime (30.6%), and nalidixic acid (6.3%). There was no resistance displayed to kanamycin and imipenem. ERY-NOV-VAN-TET and ERY-NOV-CEP-VAN-TET were the most common resistant patterns displayed by Enterobacter cloacae. The findings of this study suggest that MAs, though considered healthy, may be a reservoir of multidrug resistant opportunist pathogens.

Genetic Comparison of ESBL-Producing Escherichia coli from Workers and Pigs at Vietnamese Pig Farms

We analyzed and compared genomes of Extended Spectrum Beta-Lactamase (ESBL)-producing Escherichia coli from pigs and pig farm workers at 116 farms in Vietnam. Analyses revealed the presence of blaCTX-M-55, blaCTX-M-27, blaCTX-M-15, blaCTX-M-14, blaCTX-M-3, blaCTX-M-65, blaCTX-M-24, blaDHA-1, and blaCMY2 in both hosts. Most strains from pigs contained quinolones (qnr) and colistin resistance genes (mcr-1 and mcr-3). Isolates predominantly harbored more than one plasmid replicon and some harbored plasmid replicons on the same contigs as the ESBL genes. Five strains from farm workers of ST38 (2), ST69 (1), and ST1722 (2) were classified as either uropathogenic E. coli (UPECHM)/extraintestinal pathogenic E. coli (ExPECJJ) or UPECHM, and the remaining were genetically distinct commensals. A high heterogeneity was found among the ESBL-producing E. coli from pigs and workers, with most isolates belonging to unrelated phylogroups, serogroups, and sequence types with >4046 Single-Nucleotide Polymorphisms-(SNPs). In comparing the genomes of pig isolates to those from humans, it appeared that ESBL-producing E. coli in workers did not predominantly originate from pigs but were rather host-specific. Nevertheless, the occurrence of ESBL-producing E. coli carrying plasmid-mediated colistin and quinolone resistance genes in pigs could represent a potential source for horizontal transmission to humans through food rather than direct contact.

Antibiotic Resistance Profiles and Molecular Characteristics of Extended-Spectrum Beta-Lactamase (ESBL)-Producing Escherichia coli and Klebsiella pneumoniae Isolated From Shrimp Aquaculture Farms in Kerala, India

This study was undertaken to evaluate the prevalence of extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli and Klebsiella pneumoniae in selected shrimp aquaculture farms (n = 37) in Kerala, South India and to characterize the isolates using molecular tools. Overall, a low prevalence of ESBL-producers was found in the farms, most likely due to the reduced antibiotic usage in the shrimp farming sector. Out of the 261 samples (77 shrimp and 92 each of water and sediment), 14 (5.4%) tested positive for ESBL-E. coli or ESBL-K. pneumoniae. A total of 32 ESBL-E. coli and 15 ESBL- K. pneumoniae were recovered from these samples. All ESBL isolates were cefotaxime-resistant with minimal inhibitory concentration (MIC) ≥32 μg/ml. Of all isolates, 9 (28.1%) E. coli and 13 (86.7%) K. pneumoniae showed simultaneous resistance to tetracycline, ciprofloxacin, and trimethoprim-sulfamethoxazole. PCR analysis identified CTX-M group 1 (bla CTX-M-15 ) as the predominant ESBL genotype in both E. coli (23, 71.9%) and K. pneumoniae (15, 100%). Other beta-lactamase genes detected were as follows: bla TEM and bla SHV (11 K. pneumoniae), bla CTX-M group 9 (9 E. coli), and bla CMY-2 (2 E. coli). Further screening for AMR genes identified tetA and tetB (13, 40.6%), sul1 (11, 34.4%), sul2 (9, 28.1%), catA and cmlA (11, 34.4%), qepA and aac(6')-Ib-cr (9, 28.1%) and strAB and aadA1 (2, 6.3%) in E. coli, and qnrB (13, 86.7%), qnrS (3, 20%), oqxB (13, 86.7%), tetA (13, 86.7%), and sul2 (13, 86.7%) in K. pneumoniae isolates. Phylogenetic groups identified among E. coli isolates included B1 (4, 12.5%), B2 (6, 18.8%), C (10, 31.3%), D (3, 9.4%), and E (9, 28.1%). PCR-based replicon typing (PBRT) showed the predominance of IncFIA and IncFIB plasmids in E. coli; however, in K. pneumoniae, the major replicon type detected was IncHI1. Invariably, all isolates of K. pneumoniae harbored virulence-associated genes viz., iutA, entB, and mrkD. Epidemiological typing by pulsed-field gel electrophoresis (PFGE) revealed that E. coli isolates recovered from different farms were genetically unrelated, whereas isolates of K. pneumoniae showed considerable genetic relatedness. In conclusion, our findings provide evidence that shrimp aquaculture environments can act as reservoirs of multi-drug resistant E. coli and K. pneumoniae.

Antimicrobial-Resistant Escherichia coli Strains and Their Plasmids in People, Poultry, and Chicken Meat in Laos

Antimicrobial resistant (AMR) Enterobacterales are widely distributed among the healthy population of the Indochinese peninsula, including Laos. However, the local reservoir of these pathogens are currently not known and possible sources such as agricultural settings and food have rarely been analyzed. In this work, we investigated the extended-spectrum cephalosporin- (ESC-) and colistin-resistant Escherichia coli strains (CST-R-Ec) isolated from the gut of local people, feces of poultry, and from chicken meat (60 samples each group) in Laos. Whole-genome sequencing (WGS) analysis based on both short- and long-read sequencing approaches were implemented. The following prevalence of ESC-R-Ec and CST-R-Ec were recorded, respectively: local people (70 and 15%), poultry (20 and 23.3%), and chicken meat (21.7 and 13.3%). Core-genome analysis, coupled with sequence type (ST)/core-genome ST (cgST) definitions, indicated that no common AMR-Ec clones were spreading among the different settings. ESC-R-Ec mostly possessed bla_CTX–M–15 and bla_CTX–M–55 associated to ISEcp1 or IS26. The majority of CST-R-Ec carried mcr-1 on IncX4, IncI2, IncP1, and IncHI1 plasmids similar or identical to those described worldwide; strains with chromosomal mcr-1 or possessing plasmid-mediated mcr-3 were also found. These results indicate a high prevalence of AMR-Ec in the local population, poultry, and chicken meat. While we did not observe the same clones among the three settings, most of the bla_CTX–Ms and mcr-1/-3 were associated with mobile-genetic elements, indicating that horizontal gene transfer may play an important role in the dissemination of AMR-Ec in Laos. More studies should be planned to better understand the extent and dynamics of this phenomenon.

Skewness in the literature on infectious livestock diseases in an emerging economy - the case of Vietnam

Livestock production has increased in many emerging economies, but productivity is often substantially impaired by infectious diseases. The first step towards improved livestock health and productivity is to map the presence of livestock diseases. The objective of this review was to summarize studies conducted on such diseases in an emerging economy, Vietnam, and thereby identifying knowledge gaps that may inform the design of surveillance and control programs. Few studies were found to evaluate the distribution of infectious livestock diseases other than avian influenza. Also, many regions with dense livestock populations had received little attention in terms of disease investigation. A large proportion of the studies dealt with zoonoses and food-borne infections which might be due to funding agencies priorities. On the contrary, studies targeting infections that affect livestock and their productivity were few. We think that this limitation in scientific reports on infectious diseases that only affect livestock productivity is a common phenomenon in low and lower middle income countries. More science-based data on such diseases would help policymakers to prioritize which livestock diseases should be subject to animal health programs aimed to support rural livelihoods and economic development.

ESBL and AmpC β-Lactamase Encoding Genes in E. coli From Pig and Pig Farm Workers in Vietnam and Their Association With Mobile Genetic Elements

Animals are considered important sources of ESBL/AmpC-producing bacteria in humans. We analyzed indications of transfer of ESBL/AmpC genes between pigs and pig farmers in Vietnam by analyzing whole genome sequences of 114 ESBL/AmpC-producing E. coli isolated from the two hosts, and performed conjugation experiments and plasmid profiling to confirm that such transfer could have happened. ESBL-encoding genes detected in pigs and pig farmers included bla _CTX-M-55, bla _CTX-M-27, bla _CTX-M-65, bla _CTX-M-15, bla _CTX-M-14, bla _CTX-M-3, bla _CTX-M-24, and bla _CARB-2, and AmpC β-lactamases included bla _CMY-2, bla _DHA-1, and bla _CMY-42. The most frequent ESBL gene, bla _CTX-M-55, was carried on plasmid with replicons types IncF, IncX, IncH, IncN, IncR, and IncP. The insertion transposases downstream of the bla _CTX-M-55 gene were different in plasmids carried by different strains. The second most detected gene, bla _CTX-M-27, is found in a stable genetic arrangement with the same flanking transposons seen across strains, and the gene was located on similar conjugal IncF plasmid types, suggesting a horizontal spread of these plasmids. In three strains, we observed a novel bla _CTX-M-27 harboring IncF type of plasmid which had not been reported before. Its closest reference in NCBI was the non-ESBL Salmonella Typhimurium plasmid pB71 that might have experienced an insertion of bla _CTX-M-27. Our data also point to an emergence of plasmids co-carrying ESBL genes, mcr genes, quinolones and other antimicrobials resistance determinants, and such plasmids require special attention. Plasmids phylogeny confirmed that the bla _CTX-M-55 encoding plasmids varied considerably, while those encoding bla _CTX-M-27 were closely related. Plasmids harboring both ESBL genes were confirmed to be conjugative and not to differ in transfer efficacy. The isolates carrying the plasmids, even those with plasmids of similar types, showed wide genetic variation with high number of SNPs, suggesting horizontal spread of plasmids into different clonal lines. Their virulence profiles did not confirm to known pathotypes, suggesting that unrelated commensals are a main reservoir for ESBL and AmpC β-lactamases in both humans and pigs. Overall, despite evidence of transferability of plasmids in the analyzed strains, our findings do not support that ESBL-producing E. coli from pigs or their ESBL/AmpC encoding plasmids are commonly spread to workers in close contact with the animals.

High Carriage Rate of Extended-Spectrum β-Lactamase-Producing Escherichia coli and Klebsiella Species among Poultry Meat Vendors in Dar es Salaam: The Urgent Need for Intervention to Prevent the Spread of Multidrug-Resistant Pathogens

Background

Bacteria possessing extended-spectrum beta-lactamase (ESBL), especially E. coli and Klebsiella species, are problematic, particularly in hospitalized patients. Poultry meat vendors are at risk of carrying ESBL-producing bacteria when processing and handling meat products in an unhygienic environment. There is limited information on the carriage rate of ESBL-producing pathogens among poultry meat vendors that necessitated the conduction of the study.

Method

A cross-sectional study was conducted among poultry meat vendors in Dar es Salaam, Tanzania. Participants provided rectal swabs in transport media upon instruction. The primary isolation of ESBL-producing bacteria was carried out using MacConkey agar supplemented with ceftazidime. Identification of isolates relied on conventional methods. Double-disk synergy was the method used to confirm ESBL-producing isolates. We performed descriptive statistics using Statistical Package for Social Sciences version 23. A p value < 0.05 was considered statistically significant.

Results

A total of 300 participants were recruited from five districts, with a mean age of 27.2 ± 6.7 years. The majority was male (67.3%), and 74.7% worked as poultry meat vendors for more than one year. Out of 300 participants, 107 (35.7%) had confirmed ESBL-producing E. coli and Klebsiella spp. The majority of confirmed ESBL-producing isolates was E. coli (78.5%). Participants from Ubungo District had significantly higher carriage of ESBL-producing Escherichia coli and Klebsiella spp. (48.0%, 95% CI: 34.8–47.7) than Temeke District (21.4%, 95% CI: 13.4–32.4). Only 28.0% of participants had access to latrines at the workplace, and all working areas lacked access to running water.

Conclusion

The study revealed a relatively high fecal carriage rate of ESBL-producing E. coli and Klebsiella spp. among poultry meat vendors. Poor working environments and hygienic practices are risks for spread of these multidrug-resitant pathogens.

Impact of Sodium Alginate Packaging Film Synthesized Using Syzygium cumini Seed Extract on Multi Drug Resistant Escherichia coli Isolated from Raw Buffalo Meat

A total of 50 Escherichia coli were isolated from buffalo meat and their antibiotic profiling was carried out. 90% E. coli isolates showed resistant to two or more classes of 21 commonly used antibiotics. Moreover, there was also variation in resistance/sensitivity behavior towards antibiotics. Highest resistance was found to be against methicillin (84%) in the isolates followed by vancomicin (70%), sulphadiazine (68%) and cefaclor (66%), whereas, resistance was less common for kanamycin (8%) and chloramphenicol (4%). ECMB1, ECMA2, ECMA8, ECMS9 and ECMA31 strains showed highest MDR pattern with presence of ^bla CTX-M, qnr S and qnr B resistant genes. ECMB1 strain was resistant to 14 antibiotics belonging to 7 different classes. Therefore, ECMB1 was selected for further studies. Sodium Alginate Film incorporated with 10, 20, and 30% ethanolic extract of Syzygium cumini (EESC) were formulated and characterized using state-of-art techniques. A dose-dependent antibacterial activity against E. coli ECMB1 was recorded by the films made from EESC (EESCF). The growth kinetics of E. coli strain ECMB1 showed 9% decrease in log CFU when it was cultured in 30% EESCF as compared to control cells after 12 h of growth. Present finding highlight the efficacy and possible use of EESCF as meat packaging film to prevent food spoilage caused by MDR bacteria.

Escherichia coli as Commensal and Pathogenic Bacteria Among Food-Producing Animals: Health Implications of Extended Spectrum β-lactamase (ESBL) Production

Simple Summary

This revision is about the problem of Escherichia coli as a commensal and pathogenic bacterium among food-producing animals and health implications. Escherichia coli may play an important ecological role and can be used as a bioindicator of antimicrobial resistance. All animal species used for food production, as well as humans, carry E. coli in their intestinal tract; plus, the genetic flexibility and adaptability of this bacteria to constantly changing environments allows it to acquire a great number of antimicrobial resistance mechanisms. The majority of E. coli strains are commensals inhabiting the intestinal tract of humans and warm-blooded animals and rarely causes diseases. However, E. coli also remains as one of the most frequent causes of several common bacterial infections in humans and animals. All over the word, antibiotic resistance is commonly detected among commensal bacteria from food-producing animals, raising important questions on the potential impact of antibiotic use in animals and the possible transmission of these resistant bacteria to humans through the food chain. The use, in food-producing animals, of antibiotics that are critically important in human medicine has been implicated in the emergence of new forms of resistant bacteria, including new strains of multidrug-resistant foodborne bacteria, such as extended spectrum β-lactamase (ESBL)-producing E. coli.

Abstract

Escherichia coli are facultative, anaerobic Gram-negative rods with many facets. Within resistant bacterial populations, they play an important ecological role and can be used as a bioindicator of antimicrobial resistance. All animal species used for food production, as well as humans, carry E. coli in their intestinal tracts; plus, the genetic flexibility and adaptability of this bacteria to constantly changing environments allows it to acquire a great number of antimicrobial resistance mechanisms. Thus, the prevalence of antimicrobial resistance in these commensal bacteria (or others, such as enterococci) can be a good indicator for the selective pressure caused by the use of antimicrobial agents, providing an early warning of the emergence of antimicrobial resistance in pathogens. As many as 90% of E. coli strains are commensals inhabiting the intestinal tracts of humans and warm-blooded animals. As a commensal, it lives in a mutually beneficial association with its hosts and rarely causes diseases. However, E. coli also remains as one of the most frequent causes of several common bacterial infections in humans and animals. In humans, it is the prominent cause of enteritis, community- and hospital-acquired urinary tract infection (UTI), septicemia, postsurgical peritonitis, and other clinical infections, such as neonatal meningitis, while, in farm animals, it is more prominently associated with diarrhea. On a global scale, E. coli can be considered the most important human pathogen, causing severe infection along with other major bacterial foodborne agents, such as Salmonella spp. and Campylobacter. Thus, the importance of resistance in E. coli, typically considered a benign commensal, should not be underestimated.

Antimicrobial Resistance in Agri-Food Chain and Companion Animals as a Re-emerging Menace in Post-COVID Epoch: Low-and Middle-Income Countries Perspective and Mitigation Strategies

Antimicrobial resistance (AMR) leads to enormous financial losses from issues such as high morbidity, mortality, man-days lost, hospital length of stay, health-care, and social costs. In humans, over prescription of antimicrobials, which is presumably higher during COVID, has been identified as the major source of selection for antimicrobial resistant bacteria; however, use of antimicrobials in food and companion animals, fish, and vegetables, and the environmental resistance gene pool, also play important roles. The possibilities of unnecessary use of antibiotics as prophylaxis during and after COVID in livestock and companion animals exist in low-and middle-income countries. A considerable loss in gross domestic product (GDP) is also projected in low-and middle-income countries (LMICs) due to AMR by the year 2050, which is further going to be reduced due to economic slowdown in the post-COVID period. Veterinary hospitals dedicated to pets have cropped up, especially in urban areas of LMICs where use of antimicrobials has also been increased substantially. The inevitable preventive habit built up during COVID with the frequent use of hand sanitizer might trigger AMR due to the presence of cross-resistance with disinfectants. In LMICs, due to the rising demand for animal protein, industrial food animal production (IFAP) is slowly replacing the small-scale backyard farming system. The lack of stringent regulations and monitoring increased the non-therapeutic use of antimicrobials in industrial farms where the persistence of antimicrobial resistant bacteria has been associated with several factors other than antimicrobial use, such as co-resistance, cross-resistance, bacterial fitness, mixing of new and old animals, and vectors or reservoirs of bacterial infection. The present review describes types of antimicrobials used in agri-food chains and companion animals in LMICs with identification of the gap in data, updated categories of prevalent antimicrobial resistant bacteria, the role of animal farms as reservoirs of resistant bacteria, and mitigation strategies, with a special focus on the pivotal strategy needed in the post-COVID period.

Extended-spectrum beta-lactamase-producing Escherichia coli harbouring sul and mcr-1 genes isolates from fish gut contents in the Mekong Delta, Vietnam

This study investigated the existence of sulfonamides and colistin resistance genes among extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli recovered from fish gut in Vietnam and evaluated the susceptibility patterns of the ESBL-producing E. coli to relevant antimicrobials. A total of 88 ESBL-producing E. coli isolates were analysed for the presence of the ESBLs, sul (1, 2, 3) and mcr (1-3) genes by PCR. Antimicrobial resistance phenotypes of isolates were determined by disc diffusion. Results showed that: (i) A high prevalence of 94·3% of sulfonamide resistance was observed in 88 isolates. Moreover, the existence of 2·3% of ESBL-producing E. coli harbouring mcr-1 gene were detected; (ii) The phylogenetic types A and B1 were most frequent, and the bla_CTX-M group1 and bla_TEM genes encoding ESBL were detected in 47·7% of the isolates; (iii) ESBL-producing E. coli harbouring mcr-1 gene exhibited resistance to 11 antibiotics. The existence of mcr-1 and sul1,2,3 genes and the extremely high level of multiple drug resistance in all ESBL-producing E. coli isolates obtained from sampled fish in Vietnam is a major concern. Therefore, it is imperative to monitor ESBL-producing E. coli in the river waters of Vietnam.

The presence of colistin resistance gene mcr-1 and -3 in ESBL producing Escherichia coli isolated from food in Ho Chi Minh City, Vietnam

Colistin is indicated for the treatment of multidrug-resistant gram-negative bacterial infections. However, the spread of colistin-resistant bacteria harbouring an mcr gene has become a serious concern. This study investigated local foods in Vietnam for contamination with colistin-resistant bacteria. A total of 261 extended-spectrum β-lactamase (ESBL)- and AmpC-producing Escherichia coli isolates from 330 meat and seafood products were analysed for colistin susceptibility and the presence of mcr genes. Approximately, 24% (62/261) of ESBL- or AmpC-producing E. coli isolates showed colistin resistance; 97% (60/62) of colistin-resistant isolates harboured mcr-1, whereas 3% (2/62) harboured mcr-3. As the result of plasmid analysis of two strains, both plasmids harbouring mcr-3 revealed that plasmid replicon type was IncFII. Sequencing analysis indicated that an insertion sequence was present near mcr-3, suggesting that IncFII plasmids harbouring mcr-3 could be transferred to other bacterial species by horizontal transfer of the plasmid or transfer with some insertion sequence. In conclusion, ESBL-producing E. coli and AmpC-producing E. coli have acquired colistin resistance because 24% of such isolates show colistin resistance and 3% of the colistin-resistant strains harbour mcr-3. We reported the present of the mcr-3-carrying ESBL-producing E. coli isolated from pork in Vietnam.

Detection of Antibiotic Resistance in Escherichia coli Strains: Can Fish Commonly Used in Raw Preparations such as Sushi and Sashimi Constitute a Public Health Problem?

HIGHLIGHTS

Forty-five E. coli isolates were recovered from fresh fish. Three of the E. coli isolates produced ESBL. ESBL-producing E. coli isolates harbored the bla_CTX-M-1 and bla_TEM genes. The presence of ESBL-producing E. coli may represent a serious public health problem.

Diversity in prevalence and characteristics of ESBL/pAmpC producing E. coli in food in Germany

The spread of extended-spectrum β-lactamases (ESBLs) in Escherichia coli is a major public health issue and ESBL-producing bacteria are frequently reported in livestock. For the assessment of the role of the foodborne transmission pathway in Germany, detailed data on the prevalence and characteristics of isolates of food origin are necessary. The objective of this study was to describe the prevalence of cefotaxime resistant E. coli as well as ESBL/pAmpC-producing E. coli and their characteristics in foods in Germany. Out of 2256 food samples, the highest prevalence of cefotaxime resistant E. coli was observed in chicken meat (74.9%), followed by turkey meat (40.1%). Prevalence in beef, pork and minced meat was considerably lower (4.2-15.3%). Whereas 18.0% of the raw milk samples, collected at farm level were positive, this was true only for few cheese samples (1.3%). In one out of 399 vegetable samples a cefotaxime-resistant E. coli was isolated. ESBL resistance genes of the CTX-M-group (10.1% of all samples) were most frequently detected, followed by genes of the pAmpC (2.6%), SHV (2.0%) and TEM (0.8%) families. Distribution of ESBL/AmpC-encoding E. coli resistance genes and E. coli phylogroups was significantly different between the chicken related food samples and all other food items. Our study results reflect that consumers might get exposed to ESBL/pAmpC-producing E. coli through several food chains. These results together with those collected at primary production and in the human population in other studies will allow more detailed analysis of the foodborne pathways, considering transmission from livestock populations to food at retail and to consumers in Germany.

Pathogenic potential and the role of clones and plasmids in beta-lactamase-producing E. coli from chicken faeces in Vietnam

BACKGROUND

Antimicrobial resistance (AMR) in food-producing animals is a global public health issue. This study investigated AMR and virulence profiles of E. coli isolated from healthy chickens in Vietnam. E. coli were isolated from fecal samples collected in five chicken farms located in the provinces of Hoa Binh, Thai Nguyen and Bac Giang in the North of Vietnam. These isolates were examined by disk diffusion for their AMR, PCR for virulence and AMR genes, pulsed-field gel electrophoresis for relatedness between blaCMY-2/blaCTX-M-positive isolates, electroporation for transferability of blaCMY-2 or blaCTX-M genes and sequencing for mutations responsible for ciprofloxacin resistance.

RESULTS

Up to 99% of indicator isolates were multidrug resistant. Resistance to third-generation cephalosporins (3GC) was encoded by both blaCTX-M and blaCMY-2 genes; blaCTX-M genes being of genotypes blaCTX-M-1, - 14, - 15, - 17, - 57 and - 87, whereas ciprofloxacin resistance was due to mutations in the gyrA and parC genes. Some isolates originating from farms located in different provinces of Vietnam were found to be closely related, suggesting they may have been disseminated from a same source of contamination. Plasmids may also have played a role in the diffusion of 3GC-resistance as the blaCMY-2 gene was located on plasmids A/C and I1, and the blaCTX-M gene variants were carried by I1, FIB, R and HI1. Plasmids carrying the blaCMY-2/blaCTX-M genes also co-transferred resistance to other antimicrobials. In addition, isolates potentially capable of infecting humans, of which some produced blaCMY-2/blaCTX-M, were identified in this study.

CONCLUSIONS

Both clones and plasmids could be involved in the dissemination of 3GC-resistant E. coli within and between chicken farms in Vietnam. These results demonstrate the necessity to monitor AMR and control antimicrobial use in poultry in Vietnam.

Prevalence and risk factors for faecal carriage of Extended Spectrum β-lactamase producing Enterobacteriaceae among food handlers in lower basic schools in West Coast Region of The Gambia

BACKGROUND

The isolation of Extended spectrum βlactamase (ESBLs) producing Enterobacteriaceae among food handlers and their implication as sources of food borne outbreaks are a public health concern. This study seeks to investigate the prevalence of faecal carriage of these bacteria among food handlers in the West Coast Region of The Gambia.

METHOD

This study enrolled 600 participants from 60 Lower Basic Schools in West Coast Region of the country. Stool samples collected from the participants were presumptively screened for the ESBLs producing Enterobacteriaceae, using Drigalski agar, supplemented with 2mg/L cefotaxime. The bacterial colonies that grew on each Drigalski agar were tested for ESBL production by the double disk synergy test as recommended by Clinical and Laboratory Standard Institute (CLSI-2015). The confirmatory analysis for ESBL was determined as the zone of inhibition of cefotaxime and/or ceftazidime to ≥5mm from that of cefotaxime /clavulanicacid and/or ceftazidime/clavulanic acid. The presumptive screening of isolates for AmpC phenotypes was done by testing the organism against cefoxitin. The prevalence of the ESBL carriage was presented in percentages. The association of risk factors to the faecal carriage of ESBLs producing Enterobacteriaceae was performed by Pearson Chi-squared and Fishers Exact at (p ≤ 0.05).

RESULT

The prevalence of faecal carriage ESBL producing Enterobacteriaceae among food handlers was 5.0% (28/565). We found50% (14/28) and3.57% (1/28) ESBL producing bacteria were presumptive AmpC and carbapenemase resistance phenotype. Themost abundant ESBL producing Enterobacteriaceae were Klebsiella spp 32.1% (9/28) and Escherichia spp 28.6% (8/28). The use of antibiotics in the last 3 months was found to be significantly associated (P = 0.012) with the faecal carriage of ESBLs producing Enterobacteriaceae.

CONCLUSION

The prevalence of faecal carriage of ESBLs producing Enterobacteriaceae among food handlers in the Gambia is low. The history to use of the antibiotics in the last three months was found to be significantly associated with this prevalence. Therefore, the institution of a robust antimicrobial surveillance and treatment of patients with such infections are necessary to curb the spread of these multidrug resistant bacteria in the country. Rational prescription and usage of the antibiotics especially cephalosporin should be advocated both in public and private health facilities.

Investigation of Extended-Spectrum and AmpC β-Lactamase-Producing Enterobacteriaceae from Retail Seafood in Berlin, Germany

Retail seafood in Berlin, Germany, was investigated to detect the prevalence and quantitative load of Enterobacteriaceae that produce extended-spectrum β-lactamase (ESBL) and AmpC β-lactamase (AmpC). A total of 160 raw seafood samples were screened for the presence of these bacteria using MacConkey agar supplemented with 1 mg/L cefotaxime after nonselective enrichment. Isolated species were subsequently identified using matrix-assisted laser desorption-ionization time-of-flight analysis. ESBL and AmpC production was tested by the disk diffusion method, and ESBL and AmpC genes were characterized using real-time and conventional PCR assays with DNA sequencing. Spread plating was used for quantification of ESBL- and AmpC-producing Enterobacteriaceae. Overall, these bacteria were detected in 21.3% of seafood samples (34 of 160 samples) with prevalences of 22.5 and 20% for shrimp and bivalves, respectively. Of the positive samples, 91.2% contained an ESBL- or AmpC-producing Enterobacteriaceae load of <100 CFU/g (lower detection limit), and 8.8% contained 100 to 1,000 CFU/g. Among the 45 Enterobacteriaceae isolates, Klebsiella pneumoniae (13 isolates) and Escherichia coli (12 isolates) were the predominant species. ESBL and AmpC genes were detected in 33 isolates, with the majority of isolates harboring bla_CTX-M (27.3%), bla_CMY (21.2%), or bla_DHA (21.2%). Our study highlights the hazard associated with seafood containing ESBL- and AmpC-producing Enterobacteriaceae in Germany. Even though the contamination levels were low, the high prevalence of ESBL- and AmpC-producing Enterobacteriaceae in seafood might be of concern to public health because of the potential transmission of these bacteria from seafood to humans through the food chain.

ESBL-producing Escherichia coli and Its Rapid Rise among Healthy People

Since around the 2000s, Escherichia coli (E. coli) resistant to both oxyimino-cephalosporins and fluoroquinolones has remarkably increased worldwide in clinical settings. The kind of E. coli is also identified in patients suffering from community-onset infectious diseases such as urinary tract infections. Moreover, recoveries of multi-drug resistant E. coli from the feces of healthy people have been increasingly documented in recent years, although the actual state remains uncertain. These E. coli isolates usually produce extended-spectrum β-lactamase (ESBL), as well as acquisition of amino acid substitutions in the quinolone-resistance determining regions (QRDRs) of GyrA and/or ParC, together with plasmid-mediated quinolone resistance determinants such as Qnr, AAC(6')-Ib-cr, and QepA. The actual state of ESBL-producing E. coli in hospitalized patients has been carefully investigated in many countries, while that in healthy people still remains uncertain, although high fecal carriage rates of ESBL producers in healthy people have been reported especially in Asian and South American countries. The issues regarding the ESBL producers have become very complicated and chaotic due to rapid increase of both ESBL variants and plasmids mediating ESBL genes, together with the emergence of various "epidemic strains" or "international clones" of E. coli and Klebsiella pneumoniae harboring transferable-plasmids carrying multiple antimicrobial resistance genes. Thus, the current state of ESBL producers outside hospital settings was overviewed together with the relation among those recovered from livestock, foods, pets, environments and wildlife from the viewpoint of molecular epidemiology. This mini review may contribute to better understanding about ESBL producers among people who are not familiar with the antimicrobial resistance (AMR) threatening rising globally.

Drug resistance, AmpC-β-lactamase and extended-spectrum β-lactamase-producing Enterobacteriaceae isolated from fish and shrimp

The present study aims to detect the production of extended-spectrum beta-lactamases (ESBL) by enterobacteria isolated from samples of fresh shrimp and fish obtained from the retail trade of the city of Sobral, Ceará State, Brazil. All bacterial isolates were submitted to identification and antimicrobial susceptibility testing using aminopenicillin, beta-lactamase inhibitors, carbapenem, 1st, 2nd, 3rd and 4th generation cephalosporins, and monobactam. Three types of beta-lactamases - ESBL, AmpC and KPC - were investigated. 103 strains were identified, and the most frequent species in shrimp and fish samples was Enterobacter cloacae (n = 54). All the strains were resistant to penicillin and more than 50% of the isolates were resistant to ampicillin and cephalothin. Resistance to three 3rd generation cephalosporins (cefotaxime, ceftriaxone and ceftazidime) and one fourth generation cephalosporin (cefepime) was detected in two isolates of E. cloacae from shrimp samples. Phenotypic detection of AmpC was confirmed in seven strains. The ESBL was detected in two strains of E. cloacae from shrimp samples. No strain showed KPC production. These data can be considered alarming, since food (shrimp and fish) may be carriers of enterobacteria resistant to drugs of clinical interest.

Potential transmission opportunity of CTX-M-producing Escherichia coli on a large-scale chicken farm in Vietnam

OBJECTIVES

Extended-spectrum β-lactamase (ESBL)-producing Escherichia coli have disseminated worldwide. This study investigated bla_CTX-M-positive E. coli on a large-scale Vietnamese chicken farm and analysed whether there was any difference in prevalence and molecular characteristics of bla_CTX-M-positive E. coli between the farm and the Vietnamese community.

METHODS

Faecal samples were collected from 24 human individuals and 38 chickens from the large-scale chicken farm as well as 51 humans and 36 chickens from the community. All samples were collected between June 2013 and June 2014 in Bavi Province in the Red River Delta region of Vietnam. Molecular characterisation of CTX-M-producing E. coli and genetic relatedness among the isolates were evaluated by conventional typing methods. Antimicrobial susceptibility of the isolates was evaluated by the disk diffusion method.

RESULTS

The prevalence of bla_CTX-M-positive E. coli was 83.3%, 71.1%, 54.9% and 13.9% in farm workers, farm chickens, community individuals and community backyard chickens, respectively. On average, bla_CTX-M-positive E. coli isolates from farm chickens were resistant to 8.3 different antibiotics. The average number of detected aminoglycoside-modifying enzyme genes (3.4 genes) and the detection rate of the plasmid-mediated colistin resistance gene mcr-1 (33.3%) were higher in bla_CTX-M-positive E. coli isolated from farm chickens compared with other sampling groups. In addition, two types of indistinguishable pulsed-field gel electrophoresis (PFGE) patterns were observed in six bla_CTX-M-65-positive E. coli and three bla_CTX-M-55-positive E. coli from farm chickens.

CONCLUSIONS

These results suggest a more frequent transmission opportunity of bla_CTX-M-positive E. coli on the large-scale Vietnamese chicken farm.

Antimicrobial resistance profiles and molecular characterization of Escherichia coli strains isolated from healthy adults in Ho Chi Minh City, Vietnam

In this study, we attempted to isolate Escherichia coli from healthy adults in Ho Chi Minh City, Vietnam, and characterized its antimicrobial resistance profile, extended-spectrum β-lactamase (ESBL) genotype, phylogenetic grouping and virulence gene profile. A total of 103 E. coli isolates were obtained, and most of them were antimicrobial resistant such to streptomycin (80.6%), tetracycline (67.0%), ampicillin (65.0%), sulfamethoxsazole/trimethoprim (48.5%), nalidixic acid (43.7%), chloramphenicol (34.0%), cefotaxime (15.5%), ciprofloxacin (15.5%), kanamycin (12.6%), ceftazidime (10.7%), fosfomycin (4.9%) and gentamicin (2.9%). However, all these E. coli strains were susceptible to imipenem. Surprisingly, of 103 strains, 74 (71.8%) and 43 (41.7%) strains showed resistance to more than 3 and 5 classes of antimicrobials, respectively. Furthermore, 10 E. coli strains were ESBL-producers and positive for bla_CTX-M genes (7 for bla_CTX-M-9 and 3 for bla_CTX-M-1), while five were additionally positive for bla_TEM genes. S1-nuclease pulsed-field gel electrophoresis analysis revealed that 7 and 3 strains of E. coli carry bla_CTX-M genes on their large plasmid and chromosome, respectively. Phylogenetic analysis exhibited that majority of the E. coli strains was grouped into A (44.7%), followed by B1 (23.3%), B2 (18.4%) and D (13.6%). Virulence genes associated with diarrheagenic E. coli, such as astA, EAF, eaeA, elt and eagg were also detected in ESBL-producing E. coli as well as antimicrobial resistant strains. These data suggest that commensal E. coli of healthy human could be a reservoir for antimicrobial resistance determinants and some of them might be harmful to human.

Prevalence, antibiotic resistance, and extended-spectrum and AmpC β-lactamase productivity of Salmonella isolates from raw meat and seafood samples in Ho Chi Minh City, Vietnam

Salmonellosis is a type of foodborne disease caused by Salmonella enterica and is a frequent cause of childhood diarrhea in Vietnam. Of particular concern is the dissemination of multidrug-resistant Salmonella, as extended-spectrum β-lactamase (ESBL)-positive isolates were recently detected in children in Vietnam. In the present study, the prevalence and antibiotic resistance of Salmonella isolates obtained from 409 raw meat and seafood samples collected between October 2012 and March 2015 from slaughterhouses, wholesale fish market, and retail markets in Ho Chi Minh City, Vietnam were examined. A high rate of Salmonella contamination was detected in the pork (69.7%), poultry (65.3%), beef (58.3%), shrimp (49.1%), and farmed freshwater fish samples (36.6%). A total of 53 Salmonella serovars were found, of which S. Rissen, S. Weltevreden, S. London, S. Anatum, S. Typhimurium, and S. Corvallis were the most prevalent. In addition, 4 monophasic S. Typhimurium strains were identified using a PCR method for the detection of a specific IS200 fragment within the fliB-fliA intergenic region. The Salmonella isolates had a high prevalence (62.2%) of resistance to antimicrobial agents, particularly tetracycline (53.3%), ampicillin (43.8%), chloramphenicol (37.5%), and trimethoprim/sulfamethoxazole (31.3%). Isolates with resistance to three or more classes of antimicrobials were found (41.1%). Especially, isolates such as S. monophasic Typhimurium, S. Schwarzengrund, S. Indiana, S. Newport, S. Saintpaul and S. Bovismorbificans exhibited resistance to 6 classes of antimicrobials (3.3%). All 7 S. Indiana strains were resistant to between 4 and 6 classes of antimicrobials, including ciprofloxacin, which is commonly used for the treatment of human Salmonella infections. Two fish isolates were confirmed to be CTX-M-55 ESBL-producing Salmonella serovars Bovismorbificans and Newport, and five CMY-2 AmpC-producing Salmonella isolates of serovars Braenderup (4) and Typhimurium (1) were detected in poultry samples. The findings from this study, which is the first report of ESBL- and AmpC-producing Salmonella isolates from food in Vietnam, indicate that multidrug-resistant Salmonella are widely disseminated not only in meats, but also in seafood, within the food distribution system of Vietnam. The presence of these multidrug-resistant strains is a public health concern and suggests that the use of antimicrobial agents in both humans and animals in Vietnam should be tightly controlled.

Prevalence and Antimicrobial Susceptibility of Enterobacteriaceae Isolated from Retail Pepper in Vietnam

To investigate the microbial quality of retail pepper in Vietnam, the enumeration and detection of Enterobacteriaceae and the screening of cefotaxime (CTX)-resistant coliforms were performed by using 84 commercial samples. Although Enterobacteriaceae were isolated from 78 samples, the number of Enterobacteriaceae was lower than 1.0 log CFU/g in 46 samples. For the detection of Enterobacteriaceae with the International Organization for Standardization methods, Salmonella spp., Escherichia coli, Klebsiella pneumoniae, Cronobacter sakazakii, and Enterobacter cloacae complex were isolated from 5, 12, 36, 19, and 30 samples, respectively. During screening of CTX-resistant coliforms, K. pneumoniae, C. sakazakii, and E. cloacae complex were isolated from 8, 1, and 21 samples, respectively. Seven K. pneumoniae and seven E. cloacae complex isolates obtained in the screening of CTX-resistant coliforms were resistant to at least one of the three third-generation cephalosporins (CTX, ceftazidime, and cefpodoxime). Moreover, one E. cloacae complex cluster IV and all K. pneumoniae isolates were positive for extended-spectrum β-lactamase genes or plasmid-mediated AmpC β-lactamase genes or both. Additionally, two extended-spectrum β-lactamase-producing K. pneumoniae isolates and one AmpC β-lactamase-producing E. cloacae complex cluster IV isolate were positive for the plasmid-mediated quinolone resistance determinants and also had amino acid alterations in the quinolone resistance-determining regions of GyrA and ParC. Furthermore, 10 E. cloacae complex isolates were positive for the plasmid-mediated fosfomycin resistance gene fosA. As pepper is often consumed without a heating process, the possible spread to humans of foodborne, opportunistic, and nosocomial infection pathogens or resistance genes from foods prepared or seasoned with pepper cannot be excluded. Therefore, it is necessary to handle pepper by using hygienic conditions during the cultivation, harvesting and processing steps.