Enterobacteriaceae resistant to third-generation cephalosporins and quinolones in fresh culinary herbs imported from Southeast Asia

Streamlined fabrication of AuPtRh trimetallic nanoparticles supported on Ti3C2MXene for enhanced photocatalytic activity in cephalosporins degradation

The escalating prevalence of cephalosporin antibiotics in wastewater poses a serious threat to public health and environmental balance. Thus, it is crucial to develop effective methods for removing cephalosporin antibiotics from water sources. Herein, we propose the use of AuPtRh trimetallic nanoparticles supported on Ti3C2MXene as a photocatalyst for the degradation of cephalosporin antibiotics. Initially, AuPtRh nanoparticles were uniformly grown onto Ti3C2MXene sheets using one-step reduction technique. The prepared AuPtRh/Ti3C2MXene exhibited a complete degradation of cefixime and ceftriaxone sodium, while an impressive degradation efficiency of 91.58 % for cephalexin was achieved after 60 min of exposure to visible light, surpassing the performance of its individual AuPtRh nanoparticles and Ti3C2MXene. The enhanced photoactivity of AuPtRh/Ti3C2MXene was resulted from improved light absorption capacity and efficient generation, separation, and transfer of charge carriers driven by the formation of heterojunction between AuPtRh and Ti3C2MXene. Electron paramagnetic resonance and radicals trapping experiments results revealed that •O2- and h+ are the principal reactive species governing the degradation of cephalosporins. The photocatalyst exhibited excellent stability and could be reused four times without significant loss in efficiency. Our study highlights the potential of MXene composites for environmental remediation, offering insights into designing sustainable AuPtRh/Ti3C2MXene photocatalyst for water pollutant degradation.

Human carriage of ESBL/pAmpC-producing Escherichia coli and Klebsiella pneumoniae in relation to the consumption of raw or undercooked vegetables, fruits, and fresh herbs

We investigated to what extent the consumption of raw or undercooked vegetables, fruits, and fresh herbs influences carriage rates of ESBL/pAmpC-producing Escherichia coli and Klebsiella pneumoniae (ESBL-E/K) in the general population. We assessed long-term carriage and changes in ESBL-E/K prevalence over time, by comparing the results to findings in the same population 5 years earlier. Between July and December 2021, participants sent in two fecal samples and questionnaires, 3 months apart. Food frequency questionnaires were sent on a monthly basis. Fecal samples were cultured and screened for ESBL-E/K, and phenotypically positive isolates were sequenced. Multivariable logistic regression models were established to assess the association between the consumption of fresh produce and ESBL-E/K carriage. The ESBL-E/K prevalence was 7.6% [41/537; 95% confidence interval (CI): 5.7-10.2] in the first sampling round and 7.0% (34/489; 95% CI: 5.0-9.6) in the second. Multivariable models did not result in statistical significance for any of the selected fruit and vegetable types. Trends for increased carriage rates were observed for the consumption of raspberry and blueberry in the summer period. ESBL-E/K prevalence was comparable with the prevalence in the same cohort 5 years earlier (7.5%; 95% CI: 5.6-10.1%). In six persons (1.2%) a genetically highly homologous ESBL-E/K was found. In conclusion, the contribution of the consumption of raw fruits, vegetables, and herbs to ESBL-E/K carriage in humans in the Netherlands is probably low. Despite COVID-19 containment measures (e.g., travel restrictions, social distancing, and hygiene) the ESBL-E/K prevalence was similar to 5 years earlier. Furthermore, indications for long-term carriage were found.IMPORTANCEESBL-producing bacteria are resistant against important classes of antibiotics, including penicillins and cephalosporines, which complicates treatment of infections. Food is one of the main routes of transmission for carriage of these bacteria in the general population. Although fruits, vegetables, and herbs are generally less frequently contaminated with ESBL-producing bacteria compared to meat, exposure might be higher since these products are often eaten raw or undercooked. This research showed that the contribution of the consumption of raw or undercooked fresh produce to ESBL-E/K carriage in the general Dutch population was low. No specific types of fruit or vegetables could be identified that gave a higher risk of carriage. In addition, we demonstrated the presence of genetically highly homologous ESBL-E/K in six persons after a period of 5 years, indicative for long-term carriage.

2-Undecanone alleviates asthma by inhibiting NF-κB pathway

Asthma is characterized by airway inflammation and remodeling. 2-Undecanone (methyl nonyl ketone), a volatile organic compound originating from Houttuynia cordata, has the potential to ameliorate inflammatory diseases. This study aimed to explore potential benefits of 2-undecanone in asthma. 2-Undecanone (100, 200, or 400 mg/kg) was administered intragastrically to ovalbumin (OVA)-challenged BALB/c mice. Lung tissues were collected to observe histopathological changes, and bronchoalveolar lavage fluid (BALF) was collected for the detection of inflammatory cells and cytokine production. The results showed that 2-undecanone ameliorated OVA-induced pathologic changes of lungs, including reducing inflammatory cell infiltration, goblet cell hyperplasia, and airway smooth muscle thickness. The number of inflammatory cells and the levels of IL-4, IL-5, IL-13, and IgE in BALF were decreased by 2-undecanone in asthmatic mice. Furthermore, abnormal activation of NF-κB pathway in lung tissues of asthmatic mice was impeded by 2-undecanone. In vitro, 2-undecanone (12.5, 25, or 50 µM) suppressed platelet-derived growth factor-BB-induced proliferation and migration of primary airway smooth muscle cells (ASMCs), and inhibited the switching of ASMCs from contractile phenotype to synthetic phenotype. Consistently, 2-undecanone blocked NF-κB activation in ASMCs. Collectively, 2-undecanone relieves asthma through alleviating airway inflammation and remodeling, and this beneficial effect is achieved by inhibiting NF-κB pathway.

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.

Enrofloxacin Promotes Plasmid-Mediated Conjugation Transfer of Fluoroquinolone-Resistance Gene qnrS

This study aimed to determine the effect of enrofloxacin (ENR) on the transfer of the plasmid-mediated quinolone resistance (PMQR) gene qnrS from opportunistic pathogen Escherichia coli (E2) to Salmonella Enteritidis (SE211) and to analyze the resistance characteristics of SE211-qnrS isolates. The plasmid carrying qnrS gene of E2 was sequenced by Oxford Nanopore technology. The plasmid carrying qnrS gene belonged to incompatibility group IncY. In vitro, the transfer experiment of IncY plasmid was performed by the liquid medium conjugation method. The conjugation transfer frequency of the IncY plasmid was 0.008 ± 0.0006 in the absence of ENR, 0.012 ± 0.003 in 1/32 MIC_ENR, 0.01 ± 0.008 in 1/8 MIC_ENR, and 0.03 ± 0.015 (Mean±SD) in 1/2 MIC_ENR, respectively. After inoculation of E. coli E2 and SE211, chickens were treated with different doses of ENR (3.03, 10, and 50 mg/kg b.w.) for 7 days consecutively. To screen the SE211-qnrS strains from intestinal tract of chickens, the resistance genes and susceptibility of isolates were identified. The amount of E. coli E2 and the copy number of qnrS gene in the chicken intestinal tract were determined by colony counting and qPCR, respectively. In vivo, more SE211-qnrS strains were isolated from the treated group compared with the untreated group. SE211-qnrS strains not only obtained IncY plasmid, but also showed similar resistance phenotype as E2. In conclusion, ENR treatment can promote the spread of a IncY-resistance plasmid carrying the qnrS fluoroquinolone-resistance gene in Escherichia coli and the development of drug-resistant bacteria.

Characteristics and Global Occurrence of Human Pathogens Harboring Antimicrobial Resistance in Food Crops: A Scoping Review

Background

The role of the crop environment as a conduit for antimicrobial resistance (AMR) through soil, water, and plants has received less attention than other sectors. Food crops may provide a link between the agro-environmental reservoir of AMR and acquisition by humans, adding to existing food safety hazards associated with microbial contamination of food crops.

Objectives

The objectives of this review were: (1) to use a systematic methodology to characterize AMR in food crop value chains globally, and (2) to identify knowledge gaps in understanding exposure risks to humans.

Methods

Four bibliographic databases were searched using synonyms of AMR in food crop value chains. Following two-stage screening, phenotypic results were extracted and categorized into primary and secondary combinations of acquired resistance in microbes of concern based on established prioritization. Occurrence of these pathogen-AMR phenotype combinations were summarized by sample group, value chain stage, and world region. Sub-analyses on antimicrobial resistance genes (ARG) focused on extended-spectrum beta-lactamase and tetracycline resistance genes.

Results

Screening of 4,455 citations yielded 196 studies originating from 49 countries, predominantly in Asia (89 studies) and Africa (38). Observations of pathogen-phenotype combinations of interest were reported in a subset of 133 studies (68%). Primary combinations, which include resistance to antimicrobials of critical importance to human medicine varied from 3% (carbapenem resistance) to 13% (fluoroquinolones), whereas secondary combinations, which include resistance to antimicrobials also used in agriculture ranged from 14% (aminoglycoside resistance) to 20% (aminopenicillins). Salad crops, vegetables, and culinary herbs were the most sampled crops with almost twice as many studies testing post-harvest samples. Sub-analysis of ARG found similar patterns corresponding to phenotypic results.

Discussion

These results suggest that acquired AMR in opportunistic and obligate human pathogens is disseminated throughout food crop value chains in multiple world regions. However, few longitudinal studies exist and substantial heterogeneity in sampling methods currently limit quantification of exposure risks to consumers. This review highlights the need to include agriculturally-derived AMR in monitoring food safety risks from plant-based foods, and the challenges facing its surveillance.

High Carriage Rate of the Multiple Resistant Plasmids Harboring Quinolone Resistance Genes in Enterobacter spp. Isolated from Healthy Individuals

Antimicrobial-resistant bacteria causing intractable and even fatal infections are a major health concern. Resistant bacteria residing in the intestinal tract of healthy individuals present a silent threat because of frequent transmission via conjugation and transposition. Plasmids harboring quinolone resistance genes are increasingly detected in clinical isolates worldwide. Here, we investigated the molecular epidemiology of plasmid-mediated quinolone resistance (PMQR) in Gram-negative bacteria from healthy service trade workers. From 157 rectal swab samples, 125 ciprofloxacin-resistant strains, including 112 Escherichia coli, 10 Klebsiella pneumoniae, two Proteus mirabilis, and one Citrobacter braakii, were isolated. Multiplex PCR screening identified 39 strains harboring the PMQR genes (including 17 qnr,19 aac(6')-Ib-cr, and 22 oqxA/oqxB). The genome and plasmid sequences of 39 and 31 strains, respectively, were obtained by short- and long-read sequencing. PMQR genes mainly resided in the IncFIB, IncFII, and IncR plasmids, and coexisted with 3-11 other resistance genes. The high PMQR gene carriage rate among Gram-negative bacteria isolated from healthy individuals suggests the high-frequency transmission of these genes via plasmids, along with other resistance genes. Thus, healthy individuals may spread antibiotic-resistant bacterial, highlighting the need for improved monitoring and control of the spread of antibiotic-resistant bacteria and genes in healthy individuals.

Transmission of Escherichia coli from Manure to Root Zones of Field-Grown Lettuce and Leek Plants

Pathogenic Escherichia coli strains are responsible for food-borne disease outbreaks upon consumption of fresh vegetables and fruits. The aim of this study was to establish the transmission route of E. coli strain 0611, as proxy for human pathogenic E. coli, via manure, soil and plant root zones to the above-soil plant compartments. The ecological behavior of the introduced strain was established by making use of a combination of cultivation-based and molecular targeted and untargeted approaches. Strain 0611 CFUs and specific molecular targets were detected in the root zones of lettuce and leek plants, even up to 272 days after planting in the case of leek plants. However, no strain 0611 colonies were detected in leek leaves, and only in one occasion a single colony was found in lettuce leaves. Therefore, it was concluded that transmission of E. coli via manure is not the principal contamination route to the edible parts of both plant species grown under field conditions in this study. Strain 0611 was shown to accumulate in root zones of both species and metagenomic reads of this strain were retrieved from the lettuce rhizosphere soil metagenome library at a level of Log 4.11 CFU per g dry soil.

A review of antimicrobial resistance in imported foods

Antimicrobial resistance is one of the most serious threats to medical science. Food supply is recognized as a potential source of resistant bacteria, leading to the development of surveillance programs targeting primarily poultry, pork, and beef. These programs are limited in scope, not only in the commodities tested, but also in the organisms targeted (Escherichia coli, Salmonella, and Campylobacter); consequently, neither the breadth of food products available nor the organisms that may harbour clinically relevant and (or) mobile resistance genes are identified. Furthermore, there is an inadequate understanding of how international trade in food products contributes to the global dissemination of resistance. This is despite the recognized role of international travel in disseminating antimicrobial-resistant organisms, notably New Delhi metallo-beta-lactamase. An increasing number of studies describing antimicrobial-resistant organisms in a variety of imported foods are summarized in this review.

Microbial Safety of Smoothie Drinks from Fresh Bars Collected in Slovakia

Among the many consumers in Slovakia, smoothies are nowadays gaining popularity. Smoothie drinks are prepared from raw fruits and vegetables. Therefore, their microbiological safety depends on hygiene standards. The aim of this work was to monitor and quantify selected sensitive and antibiotic-resistant microorganisms present in collected smoothies. Twenty analyzed smoothie samples were collected from six food service establishments (fresh bars) in the capital city of Slovakia, Bratislava. Antibiotic-resistant bacteria were found in at least one of each fresh bar. Antibiotic-resistant coliform bacteria prevailed, especially in green smoothies or juices containing more vegetable ingredients. Resistance to ampicillin, ciprofloxacin, tetracycline, chloramphenicol, and gentamicin was observed in the case of coliform bacteria. More than half of the smoothie drink samples did not contain resistant enterococci. On the other hand, vancomycin-resistant enterococci were detected in 20% of samples. The most frequently isolated antibiotic-resistant strains belonged to the Enterobacter spp. or Klebsiella spp. genus. In the last part of the work, the pretreatment effect of smoothie components on the selected microorganisms' counts in the final product was investigated. Washing ingredients with an aqueous solution of a biocide agent containing silver and hydrogen peroxide proved to be the most effective way to decrease bacterial counts.

Genetic diversity and co-prevalence of ESBLs and PMQR genes among plasmid-mediated AmpC β-lactamase-producing Klebsiella pneumoniae isolates causing urinary tract infection

Klebsiella pneumoniae is an opportunistic pathogen that frequently causes nosocomial urinary tract infection (UTI). The aim of this study was to investigate the prevalence of extended-spectrum β-lactamases (ESBL), plasmid-mediated quinolone resistance (PMQR) genes, in acquired AmpC (ac-AmpC) β‑lactamase‑producing K. pneumoniae isolates from patients with nosocomial UTI and to characterize the transmissibility of plasmids harbouring multiple resistance genes. From January 2017 to June 2018, we collected 46 ac-AmpC-producing K. pneumoniae isolates causing UTI from a tertiary care hospital in China. Antimicrobial susceptibility assays showed that non-susceptibility of all isolates to third-generation cephalosporin and fluoroquinolone was very high (>80%). Diverse types of ESBLs and PMQR genes, including bla_SHV-12 (n = 23), bla_SHV-27 (n = 1)_, bla_SHV-28 (n = 2)_, bla_SHV-33 (n = 4), bla_CTX-M-3 (n = 24)_, bla_CTX-M-14 (n = 6)_, bla_CTX-M-15 (n = 6)_, bla_CTX-M-22 (n = 1) and bla_OXA-10 (n = 26)_, as well as qnrA (n = 2), qnrB (n = 39) and qnrS (n = 2) genes were identified amongst AmpC-producing K. pneumoniae isolates. The bla_AmpC, qnrB and several ESBLs genes from six strains harbouring multiple AmpC (at least two ampC) were co-transferrable to recipients via conjugation or electroporation, with IncFIA, IncFIB and IncA/C being the dominant replicons. Conserved genetic context associated with the mobilization of bla_ampC genes was detected. Forty-six isolates were categorized into 25 enterobacterial repetitive intergenic consensus (ERIC) types, and the 6 isolates harbouring multiple AmpC genes belonged to ST1 lineage. This work reports that the emergence of plasmids co-harbouring multiple resistance determinants and mediating the local prevalence in K. pneumoniae causing UTI in China.

Shared Extended-Spectrum β-Lactamase-Producing Salmonella Serovars between Agricultural and Aquatic Environments Revealed through invA Amplicon Sequencing

The presence of antibiotic-resistant Salmonella spp. in the environment is of great public health interest, worldwide. Furthermore, its extended-spectrum β-lactamase (ESBL)-producing strains constitute an emerging global health concern due to their limited treatment options in hospital. Therefore, this study aimed at characterising and tracking nonresistant and ESBL-producing Salmonella spp. from agricultural settings to nearby water sources highlighting their antibiotic resistance genes (ARG) and virulence factor (VF) distribution using a combination of both culture-dependent and independent methods. Furthermore, this study investigated the diversity and shared serovars among sampled matrices using amplicon sequencing of the invasion gene A (invA) of Salmonella spp. The results showed that soil had the highest prevalence of Salmonella spp. (62.5%, 65/104) and ESBL-producing Salmonella (34.6%, 36/104). For typed ARG, the most commonly detected gene was blaOXA with 75% (30/40), followed by blaCTX-M 67.5% (27/40),blaTEM 40% (16/40) and sul1 30% (12/40) gene; blaSHV gene was not detected in isolated ESBL-producing Salmonella spp. For VF, the most detected gene was invA (96.9%, 38/40), followed by spaM (17.5%, 7/40), spiC (40%, 16/40), orfL (32.5%, 13/40), misL 32.5% (13/40) and pipD 32.5 (13/40). For diversity analysis, soil, manure, irrigation water and nearby freshwater revealed 81, 68, 12 and 9 serovars, respectively. Soil, manure, irrigation water and freshwater stream samples shared five serovars, which indicated circulation of ESBL-producing Salmonella spp. within the agricultural environment and nearby water sources. Soil is therefore identified as one of the major reservoirs of ESBL-producing Salmonella spp. It is concluded that agricultural environment contamination may have a direct relationship with the presence of antibiotic-producing Salmonella in freshwater streams.

The Role of Pea (Pisum sativum) Seeds in Transmission of Entero-Aggregative Escherichia coli to Growing Plants

Crop plants can become contaminated with human pathogenic bacteria in agro-production systems. Some of the transmission routes of human pathogens to growing plants are well explored such as water, manure and soil, whereas others are less explored such as seeds. Fenugreek seeds contaminated with the entero-hemorrhagic Escherichia coli O104:H4 were suspected to be the principle vectors for transmission of the pathogen to sprouts at the food-borne disease outbreak in Hamburg and surrounding area in 2011. In this study we raised the questions of whether cells of the entero-aggregative E. coli O104:H4 strain 55989 is capable of colonizing developing plants from seeds and if it would be possible that, via plant internalization, these cells can reach the developing embryonic tissue of the next generation of seeds. To address these questions, we followed the fate of strain 55989 and of two other E. coli strains from artificially contaminated seeds to growing plants, and from developing flower tissue to mature seeds upon proximate introductions to the plant reproductive organs. Escherichia coli strains differing in origin, adherence properties to epithelial cells, and virulence profile were used in our experimentation to relate eventual differences in seed and plant colonization to typical E. coli properties. Experiments were conducted under realistic growth circumstances in greenhouse and open field settings. Entero-aggregative E. coli strain 55989 and the two other E. coli strains were able to colonize the root compartment of pea plants from inoculated seeds. In roots and rhizosphere soil, the strains could persist until the senescent stage of plant growth, when seeds had ripened. Colonization of the above-soil parts was only temporary at the start of plant growth for all three E. coli strains and, therefore, the conclusion was drawn that translocation of E. coli cells via the vascular tissue of the stems to developing pea seeds seems unlikely under circumstances realistic for agricultural practices. Proximate introductions of cells of E. coli strains to developing flowers also did not result in internal seed contamination, indicating that internal seed contamination with E. coli is an unlikely event. The fact that all three E. coli strains showed stronger preference for the root-soil zones of growing pea plants than for the above soil plant compartments, in spite of their differences in clinical behaviour and origin, indicate that E. coli in general will colonize root compartments of crop plants in production systems.

Circulation of Shiga Toxin-Producing Escherichia coli Phylogenetic Group B1 Strains Between Calve Stable Manure and Pasture Land With Grazing Heifers

Escherichia coli strains carrying Shiga toxins 1 and 2 (stx₁ and stx₂), intimin (eae), and hemolysin (ehxA) production genes were found in grass shoot, rhizosphere soil, and stable manure samples from a small-scale cattle farm located at the center of Netherlands, using cultivation-dependent and -independent microbiological detection techniques. Pasture land with grazing heifers in the first year of sampling in 2014 and without grazing cattle in 2015 was physically separated from the stable that housed rose calves during both years. Manure from the stable was applied to pasture via injection into soil once per year in early spring. Among a variety of 35 phylogenetic distinctly related E. coli strains, one large group consisting of 21 closely resembling E. coli O150:H2 (18), O98:H21 (2), and O84:H2 (1) strains, all belonging to phylogenetic group B1 and carrying all screened virulence traits, was found present on grass shoots (10), rhizosphere soil (3), and stable manure (8) in 2014, but not anymore in 2015 when grazing heifers were absent. Presence and absence of these strains, obtained via enrichments, were confirmed via molecular detection using PCR-NALFIA in all ecosystems in both years. We propose that this group of Shiga toxin-producing E. coli phylogenetic group B1 strains was originally introduced via stable manure injection into the pasture. Upon grazing, these potential pathogens proliferated in the intestinal track systems of the heifers resulting in defecation with higher loads of the STEC strain onto the grass cover. The STEC strain was further smeared over the field via the hooves of the heifers resulting in augmentation of the potential pathogen in the pasture in 2014, whereas in 2015, in the absence of heifers, no augmentation occurred and only a more diverse group of potentially mild virulent E. coli phylogenetic group A and B1 strains, indigenous to pasture plants, remained present. Via this model, it was postulated that human pathogens can circulate between plants and farm animals, using the plant as an alternative ecosystem. These data indicate that grazed pasture must be considered as a potential carrier of human pathogenic E. coli strains and possibly also of other pathogens.

Epidemiology of Enterobacter cloacae strains producing a carbapenemase or metallo-beta-lactamase in Vietnamese clinical settings in 2014-2017

Introduction. Little is known about the epidemiology of Enterobacter cloacae strains producing a carbapenemase or metallo-beta-lactamase in Vietnamese hospitals.Aim. This study analysed E. cloacae strains resistant to imipenem or meropenem that had been isolated from patients admitted to one of the largest hospitals in Vietnam in 2014-2017.Methodology. Eighteen Vietnamese (VN) strains were subjected to whole-genome sequencing and their sequences compared with those of 17 E. cloacae strains carrying a carbapenemase or metallo-beta-lactamase in the database (db strains).Results. Although the distribution of virulence factors did not differ significantly between VN and db strains, all 18 VN isolates harboured blaNDM-1, phylogenetic analysis revealed a high clonality of the VN strains. Bayesian phylogenetic analysis suggested that the VN strains speciated relatively recently.Conclusions. Several prevalent clones of carbapenem-resistant E. cloacae have circulated within Vietnamese hospitals. Adequate measures are needed to prevent their further spread.

Identification of antimicrobial resistant bacteria from plant-based food products imported into Canada

The role of plant-based foods in the epidemiology of antimicrobial resistance has been inadequately studied. In this investigation, resistant organisms from vegetables, fruits and spices imported into Canada were identified and characterized. A total of 143 products imported from primarily Asian and African countries were purchased from international markets in Saskatoon, Saskatchewan. Samples were selectively cultured for bacterial species where resistance is known to be emerging. The proportions of samples positive for each organism were as follows: E. coli (n = 13, 9.1%), Salmonella spp. (n = 2, 1.4%), ESBL producing Enterobacter spp. (n = 2, 1.4%) and K. pneumoniae (n = 2, 1.4%), S. aureus (n = 7, 4.9%) and Enterococcus spp. (n = 66, 46.2%). Antimicrobial minimum inhibitory concentrations were determined by broth micro-dilution and agar-dilution. Based on the susceptibility of each organism, isolates were screened for resistance genes (β-lactamases and plasmid mediated quinolones resistance determinants) by PCR. Extended-spectrum β-lactamase producing Enterobacteriaceae and methicillin resistant S. aureus (MRSA) were identified from 6/143 (4.2%) and 2/143 (1.4%) of samples respectively. The qnrB, qnrS and aac(6')-Ib-cr plasmid mediated quinolone resistance determinants were identified in 2/143 (1.4%) of samples tested. None of the Enterobacteriaceae isolates were resistant to meropenem or colistin. Similarly, all Enterococcus isolates remained susceptible to ampicillin, penicillin and vancomycin. Finding multi-drug resistant bacteria which are frequently isolated from human infections is concerning, although the contribution of the global food trade to the dissemination of resistance remains cryptic. These results suggest that imported plant-based foods may be an underappreciated source of clinically relevant resistant organisms. Further study is required to address these gaps in our understanding of the epidemiology of resistance, and the magnitude of the risk posed to human health by these organisms.

Decreasing prevalence of contamination with extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-E) in retail chicken meat in the Netherlands

Retail chicken meat is a potential source of extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-E). In the past decade, vast national efforts were undertaken to decrease the antibiotic use in the veterinary sector, resulting in a 58% decrease in antibiotic sales in the sector between 2009 and 2014. This decrease in antibiotic use was followed by a decrease in ESBL-E prevalence in broilers. The current study investigates the prevalence of contamination with ESBL-E in retail chicken meat purchased in the Netherlands between December 2013 and August 2015. It looks at associations between the prevalence of contamination with ESBL-E and sample characteristics such as method of farming (free-range or conventional), supermarket chain of purchase and year of purchase. In the current study, 352 chicken meat samples were investigated for the presence of ESBL-E using selective culture methods. Six samples were excluded due to missing isolates or problems obtaining a good quality sequence leaving 346 samples for further analyses. Of these 346 samples, 188 (54.3%) were positive for ESBL-E, yielding 216 ESBL-E isolates (Escherichia coli (n = 204), Klebsiella pneumoniae (n = 11) and Escherichia fergusonii (n = 1)). All ESBL-E isolates were analysed using whole-genome sequencing. The prevalence of contamination with ESBL-E in retail chicken meat decreased from 68.3% in 2014 to 44.6% in 2015, absolute risk difference 23.7% (95% confidence interval (CI): 12.6% - 34.1%). The ESBL-E prevalence was lower in free-range chicken meat (36.4%) compared with conventional chicken meat (61.5%), absolute risk difference 25.2% (95% CI: 12.9% - 36.5%). The prevalence of contamination with ESBL-E varied between supermarket chains, the highest prevalence of contamination was found in supermarket chain 4 (76.5%) and the lowest in supermarket chain 1 (37.8%). Pairwise isolate comparisons using whole-genome multilocus sequence typing (wgMLST) showed that clustering of isolates occurs more frequently within supermarket chains than between supermarket chains. In conclusion, the prevalence of contamination with ESBL-E in retail chicken in the Netherlands decreased over time; nevertheless, it remains substantial and as such a potential source for ESBL-E in humans.

Occurrence of Third-Generation Cephalosporins-Resistant Klebsiella pneumoniae in Fresh Fruits and Vegetables Purchased at Markets in Algeria

This study aimed to characterize third-generation cephalosporin (3GC)-resistant Klebsiella pneumoniae isolated from fresh fruits and vegetables purchased at Bejaia city, Algeria. K. pneumoniae isolates were identified by MALDI-TOF. Susceptibility to antibiotics was tested by the disk diffusion method. Whole genome sequencing (WGS) was carried out to determine sequence type (ST), plasmid incompatibility group (Inc.), and acquired antimicrobial resistance gene presence. A total of 13 3GC-resistant K. pneumoniae strains were isolated. WGS identified bla_CTX-M-15 in 11 extended-spectrum-beta-lactamases (ESBL)-K. pneumoniae and bla_DHA-1 in 2 AmpC-K. pneumoniae. The aac(6')lb-cr gene was identified in 8 out of 13 isolates. Multilocus sequence typing (MLST) evidenced five different STs, namely ST14, ST45, ST219, ST236, and ST882. MDR K. pneumoniae contaminated fresh fruits and vegetables, often eaten raw and inappropriately washed, may represent an underestimated public health threat. This study highlights that hygiene measures during harvesting and retail process are of utmost importance to limit further ESBL/AmpC spread to the consumer households.

Transferable Mechanisms of Quinolone Resistance from 1998 Onward

While the description of resistance to quinolones is almost as old as these antimicrobial agents themselves, transferable mechanisms of quinolone resistance (TMQR) remained absent from the scenario for more than 36 years, appearing first as sporadic events and afterward as epidemics. In 1998, the first TMQR was soundly described, that is, QnrA. The presence of QnrA was almost anecdotal for years, but in the middle of the first decade of the 21st century, there was an explosion of TMQR descriptions, which definitively changed the epidemiology of quinolone resistance. Currently, 3 different clinically relevant mechanisms of quinolone resistance are encoded within mobile elements: (i) target protection, which is mediated by 7 different families of Qnr (QnrA, QnrB, QnrC, QnrD, QnrE, QnrS, and QnrVC), which overall account for more than 100 recognized alleles; (ii) antibiotic efflux, which is mediated by 2 main transferable efflux pumps (QepA and OqxAB), which together account for more than 30 alleles, and a series of other efflux pumps (e.g., QacBIII), which at present have been sporadically described; and (iii) antibiotic modification, which is mediated by the enzymes AAC(6')Ib-cr, from which different alleles have been claimed, as well as CrpP, a newly described phosphorylase.

Characterization of a multidrug-resistant Klebsiella pneumoniae ST607-K25 clone responsible for a nosocomial outbreak in a neonatal intensive care unit

PURPOSE

Multidrug-resistant Klebsiella pneumoniae strains are regularly involved in hospital outbreaks. This study describes an ESBL-producing K. pneumoniae clone (ST607-K25) responsible for a nosocomial outbreak in a neonatal intensive care unit.

METHODOLOGY

Fourteen strains isolated from 13 patients were included. Antimicrobial susceptibility testing was performed by the agar diffusion method. A clonal link was first investigated by fingerprinting (ERIC-PCR and REP-PCR) then confirmed by MLST. Characterization was performed by molecular detection and identification of several drug resistance and virulence determinants.

RESULTS

All strains expressed the same antibiotype, combining ESBL production, fluoroquinolones and aminoglycoside resistance, except for one which remained susceptible to fluoroquinolones. Fingerprinting methods confirmed the clonal link and MLST identified a ST607 clone. Molecular investigations revealed: (I) genes encoding for two narrow-spectrum beta-lactamases (SHV-1 and TEM-1) and an ESBL (CTX-M-15); (II) absence of any chromosomal mutation in quinolone resistance-determining- regions (QRDR) of gyrA/gyrB and parC/parE genes; (III) genes encoding for three plasmid-mediated quinolone-resistance (PMQR) determinants: oqxAB (14/14), aac(6')-Ib-cr (14/14) and qnrB (13/14); (IV) production of a K25 capsule; and (V) carriage of three genes encoding for virulence factors: mrkD (type 3 fimbriae) (14/14), ybts (yersiniabactin) (12/14) and entB (enterobactin) (14/14).

CONCLUSION

We described a multidrug-resistant Kp ST607 clone responsible for a nosocomial outbreak in vulnerable and premature newborns. Molecular investigations allowed us to identify several resistance factors responsible for ESBL production (CTX-M-15) and quinolone resistance (three PMQR determinants). The detection of a gene (ybtS) belonging to the high-pathogenicity island yersiniabactin could partly explain its high colonization and diffusion potential.

Cephalosporin antibiotics in the aquatic environment: A critical review of occurrence, fate, ecotoxicity and removal technologies

Due to their widespread occurrence in the aquatic environment, human and veterinary cephalosporin antibiotics have been studied as water pollutants. In order to characterize environmental risks of this compound class, this review evaluates relevant data about physicochemical properties, occurrence, ecotoxicity and degradation of cephalosporins. Although application of cephalosporins is rather low compared to other antibiotics and their environmental life-time is believed to be short (i.e. days), the available data is insufficient to draw conclusions on their environmental relevance. Few studies concerning the fate of cephalosporins in soil are available, while hydrolysis and photo-degradation are suggested as the main attenuation processes in the aquatic environment. Cephalosporins have been detected in different aqueous matrices in concentrations ranging from 0.30 ng L^-1 to 0.03 mg L^-1, with sewage and wastewater being the main matrices with positive findings. For wastewater treatment purposes, several technologies have been tested for the abatement of cephalosporins, including photolysis and adsorption. In most cases, the technology employed led to complete or significant removal (>95%) of parental drugs but few authors reported on cephalosporins' metabolites and transformation products. Furthermore, the present ecotoxicological data are insufficient for comprehensive ecological risk quotient calculations. Considering the total of 53 cephalosporins, effective values (EC, LC, NOAEC, NOAEL, etc.) are only available for around 30% of parental drugs and are very scarce for cyanobacteria, which is considered to be the most sensitive group of organisms to antibiotics. Furthermore, it has been demonstrated that cephalosporins' transformation products can be more toxic and more persistent than the parental drugs. Few investigations considering this possibility are available. Consequently, more effort on ecotoxicological data generation and verification of biological inactivation of cephalosporins-related products is needed. Likewise, the lack of natural depletion rates and knowledge gaps on mixture effects for cephalosporins' degradation and toxicity have to be overcome.

Characteristics of Carbapenem-Resistant Enterobacteriaceae in Ready-to-Eat Vegetables in China

Vegetables harboring bacteria resistant to antibiotics are a growing food safety issue. However, data concerning carbapenem-resistant Enterobacteriaceae (CRE) in ready-to-eat fresh vegetables is still rare. In this study, 411 vegetable samples from 36 supermarkets or farmer's markets in 18 cities in China, were analyzed for CRE. Carbapenemase-encoding genes and other resistance genes were analyzed among the CRE isolates. Plasmids carrying carbapenemase genes were studied by conjugation, replicon typing, S1-PFGE southern blot, restriction fragment length polymorphism (RFLP), and sequencing. CRE isolates were also analyzed by pulsed-field gel electrophoresis (PFGE). Ten vegetable samples yielded one or more CRE isolates. The highest detection rate of CRE (14.3%, 4/28) was found in curly endive. Twelve CRE isolates were obtained and all showed multidrug resistance: Escherichia coli, 5; Citrobacter freundii, 5; and Klebsiella pneumoniae, 2. All E. coli and C. freundii carried bla_NDM, while K. pneumoniae harbored bla_KPC−2. Notably, E. coli with bla_NDM and ST23 hypervirulent Klebsiella pneumoniae (hvKP) carrying bla_KPC−2 were found in the same cucumber sample and clonal spread of E. coli, C. freundii, and K. pneumoniae isolates were all observed between vegetable types and/or cities. IncX3 plasmids carrying bla_NDM from E. coli and C. freundii showed identical or highly similar RFLP patterns, and the sequenced IncX3 plasmid from cucumber was also identical or highly similar (99%) to the IncX3 plasmids from clinical patients reported in other countries, while bla_KPC−2 in K. pneumoniae was mediated by similar F35:A-:B1 plasmids. Our results suggest that both clonal expansion and horizontal transmission of IncX3- or F35:A-:B1-type plasmids may mediate the spread of CRE in ready-to-eat vegetables in China. The presence of CRE in ready-to-eat vegetables is alarming and constitutes a food safety issue. To our knowledge, this is the first report of either the C. freundii carrying bla_NDM, or K. pneumoniae harboring bla_KPC−2 in vegetables. This is also the first report of ST23 carbapenem-resistant hvKP strain in vegetables.

Characterization of Escherichia coli strains isolated from raw vegetables

Vegetables are an important part of the human diet. Sometimes, contamination by pathogenic Escherichia coli can be underestimated; moreover there is a risk of antibiotic resistance spreading via the food chain. The purpose of this study was to examine the prevalence of Escherichia coli in fresh vegetables sold in retail market in the Czech Republic and to evaluate the risk to human health. Antibiotic resistance against 12 antibiotics, the presence of 12 virulence and 15 resistance genes were determined among 15 isolated strains. Most of tested strains belonged to B1 phylogenetic group, less frequently represented was B2 and D phylogroup. These results indicate that most strains are probably of human origin. All E. coli strains were resistant to at least one of twelve tested antibiotics. A multidrug resistance was observed in four strains. In this study, the presence of virulence factors Einv and papC and also genes encoding toxins (CNF1, CNF2) was detected. Nevertheless, none strain can be considered as STEC or EHEC. The widespread appearance of a growing trend associated with the prevalence of antibiotic resistance among enterobacterial isolates is undeniable and the possibility of transfer to humans cannot be ignored. Nevertheless, these results indicate that raw vegetables sold in the retail market can constitute a potential health risk for consumers.

Extended-Spectrum β-Lactamase, AmpC, and MBL-Producing Gram-Negative Bacteria on Fresh Vegetables and Ready-to-Eat Salads Sold in Local Markets

We investigated the occurrence of extended-spectrum β-lactamase (ESBL), AmpC, and carbapenemase-producing Gram-negative bacteria isolated from 160 samples of fresh vegetables (n = 80) and ready-to-eat (RTE) prepacked salads (n = 80). Phenotypic and genotypic analyses were carried out on the isolates in terms of the species present and relative resistance. Resistance to β-lactam antibiotics was found in only 44 (24 from fresh vegetables and 20 from RTE salads) of a total of 312 Gram-negative strains (14.1%). The prevalence of ESBL-producing strains from fresh vegetables was 83.3% (20/24) and 16.7% (4/24) for AmpC. Among the 20 bacterial isolates from RTE salads, 80% (16/20) were identified as ESBL-producing strains and the remaining 20% (4/20) as MBL-producing strains. PCR and sequencing confirmed the presence of bla_SHV-12, bla_CTX-M-1, bla_CTX-M-15, bla_RHAN-1, bla_ACC-1, bla_DHA-1, bla_VIM-1, and bla_IMP-1. Seven different replicons were identified, where IncHI1, FIA, and I1 were the most representative types; when compared with the Inc types, isolates from fresh vegetables and RTE salads were similar. The location of genes on a conjugative plasmid was confirmed by positive results obtained with conjugation assays. Our study has demonstrated the occurrence and distribution of ESBL/AmpC and MBL strains in fresh vegetables and RTE salads in Italy and possible public health risks associated with consumption of these fresh products.

Faecal carriage of CTX-M extended-spectrum beta-lactamase-producing Enterobacteriaceae among street children dwelling in Mwanza city, Tanzania

BACKGROUND

Data on ESBL carriage of healthy people including children are scarce especially in developing countries. We analyzed the prevalence and genotypes of ESBL-producing Enterobacteriaceae (EPE) in Tanzanian street children with rare contact to healthcare facilities but significant interactions with the environment, animals and other people.

METHODOLOGY/ PRINCIPLE FINDINGS

Between April and July 2015, stool samples of 107 street children, who live in urban Mwanza were analyzed for EPE. Intestinal carriage of EPE was found in 34 (31.8%, 95% CI; 22.7-40.3) children. Of the 36 isolates from 34 children, 30 (83.3%) were Escherichia coli (E. coli) and six Klebsiella pneumoniae (K. pneumoniae). Out of 36 isolates, 36 (100%), 35 (97%), 25 (69%) and 16 (44%) were resistant to tetracycline, trimethoprim-sulfamethoxazole, ciprofloxacin and gentamicin, respectively. Beta-lactamase genes and the multilocus sequence types of E. coli and K. pneumoniae were characterized. ESBL gene blaCTX-M-15 was detected in 75% (27/36) of ESBL isolates. Sequence types (STs) 131, 10, 448 and 617 were the most prevalent in E. coli. Use of local herbs (OR: 3.5, 95% CI: 1.51-8.08, P = 0.003) and spending day and night on streets (OR: 3.6, 95% CI: 1.44-8.97, P = 0.005) were independent predictors of ESBL carriage.

CONCLUSIONS/ SIGNIFICANCE

We observed a high prevalence of blaCTX-M-15 in EPE collected from street children in Tanzania. Detection of E. coli STs 131, 10, 38 and 648, which have been observed worldwide in animals and people, highlights the need for multidisciplinary approaches to understand the epidemiology and drivers of antimicrobial resistance in low-income countries.

From Farms to Markets: Gram-Negative Bacteria Resistant to Third-Generation Cephalosporins in Fruits and Vegetables in a Region of North Africa

The role of food in human exposure to antimicrobial-resistant bacteria is a growing food safety issue. The contribution of fruits and vegetables eaten raw to this exposure is still unclear. The evaluation of contamination levels of fruits, vegetables and the agricultural environment by third-generation cephalosporin (3GC)-resistant Gram-negative bacteria was performed by analyzing 491 samples of fruits and vegetables collected from 5 markets and 7 farms in Bejaia area, north-eastern Mediterranean coast of Algeria. Ninety soil samples and 45 irrigation water samples were also sampled in farms in order to assess them as potential inoculum sources. All samples were investigated at the same time on ceftazidime-containing selective media for 3GC-resistant Gram-negative bacteria detection and on Hektoen media, for Salmonella spp. presence. The bacteria isolated (n = 30) from fruits and vegetables, soil and irrigation water collected in the farms were almost all non-fermenting bacterial species (Stenotrophomonas, Acinetobacter, Pseudomonas, Ochrobactrum) except one strain of Enterobacter cloacae and two strains of Citrobacter murliniae, isolated on one cucumber and two tomato samples in the same farm. Greater diversity in bacterial species and antimicrobial resistance profiles was observed at markets: Enterobacteriaceae (n = 41) were as strongly represented as non-fermenting bacteria (n = 37). Among Enterobacteriaceae, E. cloacae (n = 21), and Klebsiella pneumoniae (n = 13) were the most common isolates. Most of the K. pneumoniae isolates were extended-spectrum beta-lactamase (ESBL) producers (n = 11). No Salmonella spp. was recovered in any sample. This study showed that fruits and vegetables including those which may be eaten up raw constitute a reservoir of 3GC-resistant Gram-negative bacteria and multi-drug resistant-bacteria in general that can be transferred to humans through food. The general public should be informed of this hazard for health in order to encourage good domestic hygiene practices. In addition, further investigation is needed throughout the production chain to enrol professionals in actions to reduce this contamination.

Antibiotic-Resistant Extended Spectrum ß-Lactamase- and Plasmid-Mediated AmpC-Producing Enterobacteriaceae Isolated from Retail Food Products and the Pearl River in Guangzhou, China

We conducted a survey in 2015 to evaluate the presence of extended spectrum β-lactamase (ESBL)- and plasmid-mediated AmpC-producing Enterobacteriaceae in retail food and water of the Pearl River in Guangzhou, China, as well as their antibiotic resistance profiles. Samples (88 fresh food samples and 43 water samples) from eight different districts were analyzed by direct plating and after enrichment. Multidrug-resistant strains were found in 41.7 and 43.4% of food and water samples, respectively. ESBLs were found in 3.4 and 11.6% of food and water samples, respectively, and AmpC producers were found in 13.6 and 16.3% of food and water samples, respectively. Molecular characterization revealed the domination of bla_CTX−Mgenes; plasmidic AmpC was of the type DHA-1 both in food and water samples. Thirteen of Fifty one β-lactamase-producing positive isolates were detected to be transconjugants, which readily received the β-lactamase genes conferring resistance to β-lactam antibiotics as well as some non-β-lactam antibiotics. These findings provide evidence that retail food and the river water may be considered as reservoirs for the dissemination of β-lactam antibiotics, and these resistance genes could readily be transmitted to humans through the food chain and water.

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.

Increasing Incidence of Extended-Spectrum β-Lactamase-Producing Escherichia coli in Community Hospitals throughout the Southeastern United States

OBJECTIVE To describe the epidemiology of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli (ESBL-EC) and Klebsiella pneumoniae (ESBL-KP) infections DESIGN Retrospective cohort SETTING Inpatient care at community hospitals PATIENTS All patients with ESBL-EC or ESBL-KP infections METHODS ESBL-EC and ESBL-KP infections from 26 community hospitals were prospectively entered into a centralized database from January 2009 to December 2014. RESULTS A total of 925 infections caused by ESBL-EC (10.5 infections per 100,000 patient days) and 463 infections caused by ESBL-KP (5.3 infections per 100,000 patient days) were identified during 8,791,243 patient days of surveillance. The incidence of ESBL-EC infections increased from 5.28 to 10.5 patients per 100,000 patient days during the study period (P=.006). The number of community hospitals with ESBL-EC infections increased from 17 (65%) in 2009 to 20 (77%) in 2014. The median ESBL-EC infection rates among individual hospitals with ≥1 ESBL-EC infection increased from 11.1 infections/100,000 patient days (range, 2.2-33.9 days) in 2009 to 22.1 infections per 100,000 patient days (range, 0.66-134 days) in 2014 (P=.05). The incidence of ESBL-KP infections remained constant over the study period (P=.14). Community-associated and healthcare-associated ESBL-EC infections trended upward (P=.006 and P=.02, respectively), while hospital-onset infections remained stable (P=.07). ESBL-EC infections were more common in females (54% vs 44%, P<.001) and Caucasians (50% vs 40%, P<.0001), and were more likely to be isolated from the urinary tract (61% vs 52%, P<.0001) than ESBL-KP infections. CONCLUSIONS The incidence of ESBL-EC infection has increased in community hospitals throughout the southeastern United States, while the incidence of ESBL-KP infection has remained stable. Community- and healthcare-associated ESBL-EC infections are driving the upward trend. Infect. Control Hosp. Epidemiol. 2015;37(1):49-54.

First detection of Klebsiella variicola producing OXA-181 carbapenemase in fresh vegetable imported from Asia to Switzerland

Background

The emergence and worldwide spread of carbapenemase-producing Enterobacteriaceae is of great concern to public health services. The aim of this study was to investigate the occurrence of carbapenemase-producing Enterobacteriaceae in fresh vegetables and spices imported from Asia to Switzerland.

Findings

Twenty-two different fresh vegetable samples were purchased in March 2015 from different retail shops specializing in Asian food. The vegetables included basil leaves, bergamont leaves, coriander, curry leaves, eggplant and okra (marrow). Samples had been imported from Thailand, the Socialist Republic of Vietnam and India. After an initial enrichment-step, carbapenemase-producing Enterobacteriaceae were isolated from two carbapenem-containing selective media (SUPERCARBA II and Brilliance CRE Agar). Isolates were screened by PCR for the presence of bla_KPC, bla_NDM, bla_OXA-48-like and bla_VIM. An OXA-181-producing Klebsiella variicola was isolated in a coriander sample with origin Thailand/Vietnam. The bla_OXA-181 gene was encoded in a 14′027 bp region flanked by two IS26-like elements on a 51-kb IncX3-type plasmid.

Conclusions

The results of this study suggest that the international production and trade of fresh vegetables constitute a possible route for the spread of carbapenemase-producing Enterobacteriaceae. The presence of carbapenemase-producing organisms in the food supply is alarming and an important food safety issue.

Nonmedical Uses of Antibiotics: Time to Restrict Their Use?

The global crisis of antibiotic resistance has reached a point where, if action is not taken, human medicine will enter a postantibiotic world and simple injuries could once again be life threatening. New antibiotics are needed urgently, but better use of existing agents is just as important. More appropriate use of antibiotics in medicine is vital, but the extensive use of antibiotics outside medical settings is often overlooked. Antibiotics are commonly used in animal husbandry, bee-keeping, fish farming and other forms of aquaculture, ethanol production, horticulture, antifouling paints, food preservation, and domestically. This provides multiple opportunities for the selection and spread of antibiotic-resistant bacteria. Given the current crisis, it is vital that the nonmedical use of antibiotics is critically examined and that any nonessential use halted.

Multidrug-Resistant and Extended Spectrum Beta-Lactamase-Producing Escherichia coli in Dutch Surface Water and Wastewater

OBJECTIVE

The goal of the current study was to gain insight into the prevalence and concentrations of antimicrobial resistant (AMR) Escherichia coli in Dutch surface water, and to explore the role of wastewater as AMR contamination source.

METHODS

The prevalence of AMR E. coli was determined in 113 surface water samples obtained from 30 different water bodies, and in 33 wastewater samples obtained at five health care institutions (HCIs), seven municipal wastewater treatment plants (mWWTPs), and an airport WWTP. Overall, 846 surface water and 313 wastewater E. coli isolates were analysed with respect to susceptibility to eight antimicrobials (representing seven different classes): ampicillin, cefotaxime, tetracycline, ciprofloxacin, streptomycin, sulfamethoxazole, trimethoprim, and chloramphenicol.

RESULTS

Among surface water isolates, 26% were resistant to at least one class of antimicrobials, and 11% were multidrug-resistant (MDR). In wastewater, the proportions of AMR/MDR E. coli were 76%/62% at HCIs, 69%/19% at the airport WWTP, and 37%/27% and 31%/20% in mWWTP influents and effluents, respectively. Median concentrations of MDR E. coli were 2.2×10(2), 4.0×10(4), 1.8×10(7), and 4.1×10(7) cfu/l in surface water, WWTP effluents, WWTP influents and HCI wastewater, respectively. The different resistance types occurred with similar frequencies among E. coli from surface water and E. coli from municipal wastewater. By contrast, among E. coli from HCI wastewater, resistance to cefotaxime and resistance to ciprofloxacin were significantly overrepresented compared to E. coli from municipal wastewater and surface water. Most cefotaxime-resistant E. coliisolates produced ESBL. In two of the mWWTP, ESBL-producing variants were detected that were identical with respect to phylogenetic group, sequence type, AMR-profile, and ESBL-genotype to variants from HCI wastewater discharged onto the same sewer and sampled on the same day (A1/ST23/CTX-M-1, B23/ST131/CTX-M-15, D2/ST405/CTX-M-15).

CONCLUSION

In conclusion, our data show that MDR E. coli are omnipresent in Dutch surface water, and indicate that municipal wastewater significantly contributes to this occurrence.

Detection of extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae in vegetables, soil and water of the farm environment in Tunisia

One-hundred-nine samples of 18 different farms (49 of food-vegetables, 41 of soil and 19 of irrigation water) and 45 vegetable food samples of 13 markets were collected in Tunisia. These samples were inoculated in MacConkey agar plates supplemented with cefotaxime (2 μg/ml). ESBL-producing Enterobacteriaceae (ESBL-Eb) were detected in 10 of the 109 farm samples (vegetables, 8.2%; soil, 7.3%; water, 15.8%), and in 4 of 45 vegetables of markets (8.9%), recovering 15 ESBL-Eb. Isolates and ESBL genes detected were: Escherichia coli (n=8: 5 blaCTX-M-1, 2 blaCTX-M-15 and one blaCTX-M-14), Citrobacter freundii (n=4: 3 blaCTX-M-15 and one blaSHV-12), Enterobacter hormaechei (n=2: 2 blaCTX-M-15) and Klebsiella pneumoniae (n=1, blaCTX-M-15). The ISEcp1 sequence was found upstream of blaCTX-M genes in 13 of 14 strains (in three cases truncated by IS5), and orf477 or IS903 downstream. Class 1 integrons were detected in five strains and contained two gene cassette arrangements (dfrA17-aadA5 and aadA1). Most isolates tested showed a multiresistant phenotype. All blaCTX-M-15-positive strains carried the aac(6')-1b-cr gene, that affects to amikacin-tobramycin-kanamycin-ciprofloxacin. Five ESBL-Eb strains carried genes of the qnr family. The 8 ESBL-positive E. coli isolates were typed as: ST58/B1 (n=3) and ST117/D, ST131/B2, ST10/A, ST23/A, and the new ST3496/D (one strain, each). From 1-2 plasmids were detected in all ESBL-positive E. coli isolates (63-179 kb). The ESBL genes were transferred by conjugation in 4 blaCTX-M-1-positive E. coli strains, and transconjugants acquired a 97 kb IncI1 plasmid. ESBL-Eb isolates are frequently disseminated in vegetable farms and potentially could be transmitted to humans through the food chain.

Complete Genome Sequences of IncI1 Plasmids Carrying Extended-Spectrum β-Lactamase Genes

Extended spectrum beta-lactamases (ESBLs) confer resistance to clinically relevant antibiotics. Often, the resistance genes are carried by conjugative plasmids which are responsible for dissemination. Five IncI1 plasmids carrying ESBLs from commensal and clinical Escherichia coli isolates were completely sequenced and annotated along with a non-ESBL carrying IncI1 plasmid.

Prevalence of antibiotic resistant bacteria in healthy adults, foods, food animals, and the environment in selected areas in Thailand

OBJECTIVES

The aim of this study was to determine the prevalence of antibiotic-resistant bacteria, especially extended-spectrum beta-lactamase (ESBL) producing Escherichia coli, in samples from healthy adults, foods, food animals, and the environment in selected areas of Thailand.

METHODS

Samples were collected from stool specimens from adult food factory and food animal farm workers, fresh and cooked foods sold at markets, rectal swabs of healthy pigs and chickens, fresh pork meat from slaughterhouses, water samples from canals as well as fish and shrimp farm ponds, and stagnant water sources on pig farms. Antibiotic susceptibility was determined using the disk diffusion or agar dilution methods. Extended-spectrum beta-lactamase production was assayed using a double disk diffusion method.

RESULTS

Among 544 healthy adult food factory workers, 75·5% were positive for ESBL producing E. coli, while 77·3% of E. coli isolated from 30 healthy animal farm workers were positive. Amongst healthy food animals, ESBL producing status among E. coli isolates were more commonly detected in pigs (76·7%) than broilers (40%). Extended-spectrum beta-lactamase producing E. coli seemed to be more prevalent in fresh meat samples than in fresh vegetables, in fresh foods than in cooked foods, and in water samples collected from the animal farms than those from canals and fish and shrimp ponds.

CONCLUSIONS

Extended-spectrum beta-lactamase producing E. coli isolates are prevalent amongst healthy individuals, foods along the food production chain from farms to consumers, and in the environment in selected areas in Thailand.