Transmission Of Antibiotic Resistance Research Articles

Screening and Identification of Antibiotic Resistant Gene int1 in Coliforms Isolated From Drinking Water

Antibiotic-resistance genes carried by coliforms in drinking water is a concerning issue for public health in Bangladesh. This research was carried out to identify coliforms in drinking water and to understand the importance of the int1 gene of coliforms in the spread of resistance to bacterial antibiotics through consumption of contaminated water. A total of 31 drinking water samples were collected from restaurants ( n = 18), health center ( n = 9), and residences ( n = 4) located in Chattogram City, Bangladesh. The isolation and identification of coliforms was performed on selective media with a combination of biochemical and molecular analysis. PCR amplification of the LacZ, uidA and int1 genes was carried out for the identification of the coliform and fecal coliform and antibiotic resistant gene, respectively. Antimicrobial susceptibility test was performed according to the Kirby-Bauer disk diffusion method with McFarland standard against three selective antibiotics including co-trimoxazole, ciprofloxacin, and ampicillin. Of 31 drinking water samples, coliforms were detected within 32% ( n = 10) of the water samples, nine samples were collected in restaurants and one sample in a residence. But no coliform was detected in the drinking water of the health center. Among the identified coliforms, the prevalence of fecal coliforms and the int1 gene was 60% ( n = 6) and 40% ( n = 4), relatively. All isolates containing the int1 microbial-resistance gene were resistant to ampicillin.This study shows that drinking water consumed in different restaurants located in Chattogram, Bangladesh is contaminated by antibiotic-resistant gene bearing coliforms that not only increase the risk of water-borne disease, but also may be the major cause of antibiotic resistance transmission in this part of Bangladesh.

The risk of transmitting antibiotic resistance through endophytic bacteria.

Antibiotic resistance is a global human health threat distributed across humans, animals, plants, and the environment. Under the One-Health concept (humans, animals, and environment), the contamination of water bodies and soil by antibiotic-resistant bacteria cannot be dissociated from its potential transmission to humans. Edible plants can be colonized by a vast diversity of bacteria, representing an important link between the environment and humans in the One-Health triad. Based on multiple examples of bacterial groups that comprise endophytes reported in edible plants, and that have close phylogenetic proximity with human opportunistic pathogens, we argue that plants exposed to human-derived biological contamination may represent a path of transmission of antibiotic resistance to humans.

Interactions and associated resistance development mechanisms between microplastics, antibiotics and heavy metals in the aquaculture environment

AbstractMicroplastics (MPs), antibiotics and heavy metals unavoidably contaminate the aquaculture environment, with serious ecological and human health consequences. Antibiotic‐resistance genes (ARGs) and metal resistance genes (MRGs) are induced in microorganisms in the environment as a defence mechanism against antibiotics and heavy metals respectively. Furthermore, heavy metals in the aquaculture environment will cause bacteria to employ antibiotic resistance through co‐selection (co‐resistance or cross‐resistance) and other potential mechanisms. MPs may also act as potential carriers of multidrug resistance in aquaculture environments because they are hotspots for the enrichment and transmission of antibiotic resistance. Multidrug‐resistant (MDR) microorganisms in the aquaculture environment may infiltrate aquatic organisms via the food chain (eg MDR‐microorganisms→myctophids→ tuna/ squid/ whales/ seabirds/ seals), and after long‐term enrichment, they may gain access to the human body, posing a major risk to aquaculture and human health. As a result, this review article summarises contamination of MPs, heavy metal and antibiotics in global aquaculture settings; discusses the generation of ARGs, MRGs and common selection mechanisms for resistance development and emphasises the role of MPs as hot spots for antibiotic‐resistance selective enrichment, as well as potential carriers of multi‐drug‐resistant genes (MDRGs), in the aquaculture environment, posing an increasing threat to aquaculture and even human health.

Isolation of Multi-Drug Resistant Potential Pathogenic Bacteria From Blow Fly Collected From Different Areas of Dhaka City

The research work was conducted for isolation and identification of potential pathogenic bacteria from blow fly (Calliphora spp.) and to investigate their antibiotic susceptibility. For this purpose, 20 blow flies were collected from 4 selected areas (Curzon Hall, Dhaka Medical College Hospital, Fruit Store and Fish Market) of Dhaka city. A total of 40 samples (20 from external surface and 20 from alimentary gut homogenates) were prepared from the blow flies. Among the total 20 flies, 3(15%) were collected from Curzon Hall and 5(12.5%) isolates were obtained from them; 6(30%) flies were collected from DMCH which had 11(27.5%) isolates; 5(25%) flies were collected from fruit stores and 10(25%) isolates were collected from there; 6(30%) flies were collected from fish market and 14(35%) isolates were collected from there. The isolated bacteria were presumptively identified as Escherichia coli, 12 (30%); Salmonella spp., 8 (20%); Shigella spp., 4(10%); Enterobacter spp., 3 (7.5%); Klebsiella spp., 2 (5%); Bacillus spp., 7 (17.5%) and Staphylococcus spp., 4 (10%) in number which were based on morphology as observed under microscope as well as cultural and biochemical properties. All of these isolates were resistant to various antibiotics. Bacterial susceptibility showed that E. coli isolates were highly resistant (66.6%) to Penicillin, Salmonella spp. mostly resistant (62.5%) to Penicillin and Tetracycline. Klebsiella spp. Isolates were 100% resistant to Penicillin and 100% sensitive to Ciprofloxacin, Imipenem and Tetracycline. In case of Shigella spp. and Enterobacter spp., 75% and 100% isolates were resistant to Penicillin respectively. Among the Staphylococcus spp. isolates, 75% were resistant to Ampicillin and Penicillin. In case of Bacillus spp. isolates, 57.2% were resistant to Penicillin and 100% sensitive to Imipenem. Antibiotic resistance of these species affect our human health also. This study demonstrated the potential of blow flies as a vector of various pathogenic microorganisms and a mode of transmission of antibiotic resistance. Bangladesh J. Zool. 49 (2): 205-214, 2021

Distribution of antibiotic resistance genes from human and animal origins to their receiving environments: A regional scale survey of urban settings

Antibiotic resistance is a growing problem for ecosystem health and public healthcare. Hence, the transmission of antibiotic resistance from human and animal origins to natural environments requires careful investigation. In this study, nine antibiotic resistance genes (ARGs), three mobile genetic elements (MGEs), and their relations with antibiotics, heavy metals, and microbiota were investigated in 16 sample sites (Xinxiang, China). Fluoroquinolones (0.13–14.22 μg/L) were most abundant in hospital effluent and oxytetracycline (251.86–5817.47 μg/kg) in animal manure. Animal manure showed the highest levels of zinc (80.79–2597.14 mg/kg) and copper (32.47–85.22 mg/kg), possibly affecting the prevalence of intI1 and aac(6′)-Ib genes. Aminoglycoside and sulfonamide resistance genes (aac(6’)-Ib, aadA, and sul1) were the main ARGs in this area. In addition, the detected ARGs and MGEs were higher in animal manure than in hospital effluent, except for the sul1 gene. On the other hand, the incomplete removal of antibiotics (29.76–100%), heavy metals (31.25–100%), and ARGs (1–3 orders of magnitude) in MWWTPs resulted in the accumulation of these contaminants in the receiving river. Network analysis suggested that the potential hosts (Jeotgalibaca, Atopostipes, Corynebacterium_1, etc.) of ARGs were more predominant in animal manure rather than hospital effluent, indicating a higher ARG transfer potential in animal manure compared with hospital sources. These results provide useful insights into the different migration and dissemination routes of antibiotics, heavy metals, ARGs, and microbiota from anthropogenic and animal origins to their receiving environments via MWWTP discharge and manure fertilization.

Antibiotic resistance in the environment.

Antibiotic resistance is a global health challenge, involving the transfer of bacteria and genes between humans, animals and the environment. Although multiple barriers restrict the flow of both bacteria and genes, pathogens recurrently acquire new resistance factors from other species, thereby reducing our ability to prevent and treat bacterial infections. Evolutionary events that lead to the emergence of new resistance factors in pathogens are rare and challenging to predict, but may be associated with vast ramifications. Transmission events of already widespread resistant strains are, on the other hand, common, quantifiable and more predictable, but the consequences of each event are limited. Quantifying the pathways and identifying the drivers of and bottlenecks for environmental evolution and transmission of antibiotic resistance are key components to understand and manage the resistance crisis as a whole. In this Review, we present our current understanding of the roles of the environment, including antibiotic pollution, in resistance evolution, in transmission and as a mere reflection of the regional antibiotic resistance situation in the clinic. We provide a perspective on current evidence, describe risk scenarios, discuss methods for surveillance and the assessment of potential drivers, and finally identify some actions to mitigate risks.

Identification of the Plasmid-Mediated Colistin Resistance Gene mcr-1 in Escherichia coli Isolates From Migratory Birds in Guangdong, China.

We determined the prevalence and transmission characteristics of mcr-1-positive Escherichia coli (MCRPEC) isolates from migratory birds Anser indicus in Guangdong, China. We identified 22 MCRPEC from 303 A. indicus fecal samples (7.3%) in Guangzhou, Zhaoqing, and Futian. The mcr-1 gene coexisted with 24 other types of antibiotic resistance genes (ARG), and 11 ARGs were highly prevalent at levels >50%. The MCRPEC displayed a diversity of sequence types (ST), and 19 distinct STs were identified with ST10, ST1146, and ST1147 as the most prevalent. In addition, these MCRPEC from birds were closely related phylogenetically to those from other sources in China. Whole-genome sequencing analysis demonstrated that mcr-1 was located on IncX4 (n=9, 40.9%), IncI2 (n=5, 22.7%) and IncP (n=1, 4.5%) plasmids and the latter shared an identical plasmid backbone with other sources. These results highlight the significance of migratory birds in the transmission of antibiotic resistance and provide powerful evidence that migratory birds are potential transmitters of antibiotic resistance.

IS1294 Reorganizes Plasmids in a Multidrug-Resistant Escherichia coli Strain.

ABSTRACTThe aims of this study were to elucidate the role of IS1294 in plasmid reorganization and to analyze biological characteristics of cointegrates derived from different daughter plasmids. The genetic profiles of plasmids in Escherichia coli strain C21 and its transconjugants were characterized by conjugation, S1 nuclease pulsed-field gel electrophoresis (S1-PFGE), Southern hybridization, whole-genome sequencing (WGS) analysis, and PCR. The traits of cointegrates were characterized by conjugation and stability assays. blaCTX-M-55-bearing IncI2 pC21-1 and nonresistant IncI1 pC21-3, as conjugative helper plasmids, were fused with nonconjugative rmtB-bearing IncN-X1 pC21-2, generating cointegrates pC21-F1 and pC21-F2. Similarly, pC21-1 and pC21-3 were fused with nonconjugative IncF33:A−:B− pHB37-2 from another E. coli strain to generate cointegrates pC21-F3 and pC21-F4 under experimental conditions. Four cointegrates were further conjugated into the E. coli strain J53 recipient at high conjugation frequencies, ranging from 2.8 × 10−3 to 3.2 × 10−2. The formation of pC21-F1 and pC21-F4 was the result of host- and IS1294-mediated reactions and occurred at high fusion frequencies of 9.9 × 10−4 and 2.1 × 10−4, respectively. Knockout of RecA resulted in a 100-fold decrease in the frequency of plasmid reorganization. The phenomenon of cointegrate pC21-F2 and its daughter plasmids coexisting in transconjugants was detected for the first time in plasmid stability experiments. IS26-orf-oqxAB was excised from cointegrate pC21-F2 through a circular intermediate at a very low frequency, which was experimentally observed. To the best of our knowledge, this is the first report of IS1294-mediated fusion between plasmids with different replicons. This study provides insight into the formation and evolution of cointegrate plasmids under different drug selection pressures, which can promote the dissemination of MDR plasmids.IMPORTANCE The increasing resistance to β-lactams and aminoglycoside antibiotics, mainly due to extended-spectrum β-lactamases (ESBLs) and 16S rRNA methylase genes, is becoming a serious problem in Gram-negative bacteria. Plasmids, as the vehicles for resistance gene capture and horizontal gene transfer, serve a key role in terms of antibiotic resistance emergence and transmission. IS26, present in many antibiotic-resistant plasmids from Gram-negative bacteria, plays a critical role in the spread, clustering, and reorganization of resistance determinant-encoding plasmids and in plasmid reorganization through replicative transposition mechanisms and homologous recombination. However, the role of IS1294, present in many MDR plasmids, in the formation of cointegrates remains unclear. Here, we investigated experimentally the intermolecular recombination of IS1294, which occurred with high frequencies and led to the formation of conjugative MDR cointegrates and facilitated the cotransfer of blaCTX-M-55 and rmtB, and we further uncovered the significance of IS1294 in the formation of cointegrates and the common features of IS1294-driven cointegration of plasmids.

Assessment of the Bacterial Pollution and Detection of Antibiotic Resistance Genes in Benin: Case of the Hydrographic Channel Complex Cotonou-Nokoué Lake.

The study aims to document the level of contamination of the aquatic ecosystem of the Cotonou-Lake Nokoué canal hydrographic complex by multidrug-resistant bacteria and their resistance genes. For this purpose, water samples were taken from several points of the complex and from the sediments at the depth of the lake. Samples of several species of freshly caught fish products from the lake were also collected. Bacteriological analyses were carried out according to the AFNOR standard (NF U: 47–100). The identification of the different bacterial species isolated was then carried out using the API 20E gallery and specific biochemical tests. The antibiogram of the strains was performed according to the recommendations of the EUCAST. Molecular characterization of the identified strains was carried out by searching for resistance and virulence genes. The results obtained revealed the presence of several bacterial species in water samples and in sediment and intestine samples of fishery products with a predominance of Gram-negative bacilli. The resistance profile of Gram-negative bacilli showed a total resistance to metronidazole (100%). 23% of the strains were also resistant to ciprofloxacin, 41% to amoxicillin, and 60% to aztreonam. Of the Gram-positive cocci identified, 66% was resistant to vancomycin, 7.5% to ciprofloxacin, 71% to erythromycin, and 22% to tetracycline. Regarding the genes sought, blaTEM (46%), blaSHV (24%), and blaCTX-M-15 (31%) were present in the genome of Gram-negative bacilli as resistance genes and fimH (41%) as virulence gene. As for Gram-positive cocci, the van B gene was completely absent. The van A was present at 6.25% in Staphylococcus aureus and mecA at 21.88 and 33.33%, respectively, in Staphylococcus aureus and coagulase-negative staphylococci strains. The high resistance of isolated bacterial strains is a matter of concern and calls for a rational use of antibiotics in order to avoid the transmission of antibiotic resistance from the environment to humans.

Migratory birds travelling to Bangladesh are potential carriers of multi-drug resistant Enterococcus spp., Salmonella spp., and Vibrio spp.

Antimicrobial resistance (AMR) is a major health crisis globally. Migratory birds could be a potential source for antibiotic resistant (ABR) bacteria. Not much is known about their role in the transmission of ABR in Bangladesh. In this study, a total of 66 freshly dropped fecal materials of migratory birds were analyzed. Bacterial isolation and identification were based on cultural properties, biochemical tests, and polymerase chain reaction (PCR). The disk diffusion method was employed to evaluate antibiogram profiles. By PCR, out of 66 samples, the detection rate of Enterococcus spp. (60.61%; 95% confidence interval: 48.55–71.50%) was found significantly higher than Salmonella spp. (21.21%; 95% CI: 13.08–32.51%) and Vibrio spp. (39.40%; 95% CI: 28.50–51.45%). Enterococcus isolates were frequently found resistant (100–40%) to ampicillin, streptomycin, meropenem, erythromycin, and gentamicin; Salmonella isolates were frequently resistant (72–43%) to chloramphenicol, tetracycline, ampicillin, streptomycin, and erythromycin; and Vibrio spp. isolates were frequently resistant (77–31%) to vancomycin, ampicillin, erythromycin, tetracycline, and streptomycin. In addition, 60% (95% CI: 44.60–73.65%) Enterococcus spp., 85.71% (95% CI: 60.06–97.46%) Salmonella spp., and 76.92% (95% CI: 57.95–88.97%) Vibrio spp. isolates were multi-drug resistant (MDR) in nature. Three isolates (one from each bacterium) were found resistant against six classes of antibiotics. The bivariate analysis revealed strong associations (both positive and negative) between several antibiotic pairs which were resistant to isolated organisms. To the best of our knowledge, this is the first study in detecting MDR Enterococcus spp., Salmonella spp., and Vibrio spp. from migratory birds travelling to Bangladesh. Frequent detection of MDR bacteria from migratory birds travelling to Bangladesh suggests that these birds have the potential to carry and spread ABR bacteria and could implicate potential risks to public health. We recommend that these birds should be kept under an AMR surveillance program to minimize the potential risk of contamination of the environment with ABR as well as to reduce their hazardous impacts on health.

Metagenomic profiles and health risks of pathogens and antibiotic resistance genes in various industrial wastewaters and the associated receiving surface water

The aquatic environment may represent an essential route for transmission of antibiotic resistance to opportunistic human pathogens. Since industrial wastewater is discharged into the river after treatment, understanding the distribution of antibiotic resistance genes (ARGs) in river systems and the possibility of pathogens acquiring antibiotic resistance are challenges with far-reaching significance. This work mainly studied distribution profiles of pathogens and ARGs, and compared their health risk in various industrial wastewater with that of river water. Results showed that 166 pathogens were concurrently shared by the six water samples, with Salmonella enterica and Pseudomonas aeruginosa being the most abundant, followed by Fusarium graminearum and Magnaporthe oryzae. The similar composition of the pathogens suggests that pathogens in river water may mainly come from sewage discharge of slaughterhouses and that changes in water quality contribute significantly to the prevalence of these pathogens. Of the 57 ARG types detected, bacitracin was the most abundant, followed by sulfonamide, chloramphenicol, tetracycline, and aminoglycoside. Strikingly, the wastewater from a pharmaceutical factory producing Chinese medicine was also rich in bacA, sul1, mexW, mexB, mexF and oprn. It can be seen from the co-occurrence patterns that pathogens and the main ARGs have strong co-occurrence. Higher abundance of offensive virulence factors in industrial wastewater and their strong correlation with pathogens containing ARGs suggest higher microbiological risk. These findings highlight the need to assess ARG acquisition by pathogens in the surface water of human-impacted environments where pathogens and ARGs may co-thrive.

Environmental Spread of Antibiotic Resistance.

Antibiotic resistance represents a global health concern. Soil, water, livestock and plant foods are directly or indirectly exposed to antibiotics due to their agricultural use or contamination. This selective pressure has acted synergistically to bacterial competition in nature to breed antibiotic-resistant (AR) bacteria. Research over the past few decades has focused on the emergence of AR pathogens in food products that can cause disease outbreaks and the spread of antibiotic resistance genes (ARGs), but One Health approaches have lately expanded the focus to include commensal bacteria as ARG donors. Despite the attempts of national and international authorities of developed and developing countries to reduce the over-prescription of antibiotics to humans and the use of antibiotics as livestock growth promoters, the selective flow of antibiotic resistance transmission from the environment to the clinic (and vice-versa) is increasing. This review focuses on the mechanisms of ARG transmission and the hotspots of antibiotic contamination resulting in the subsequent emergence of ARGs. It follows the transmission of ARGs from farm to plant and animal food products and provides examples of the impact of ARG flow to clinical settings. Understudied and emerging antibiotic resistance selection determinants, such as heavy metal and biocide contamination, are also discussed here.

Antimicrobial Resistance Trends in Staphylococcus aureus Strains Carried by Poultry in North of Morocco: A Preliminary Analysis

The transmission of antibiotic resistance to human population through food consumption is a global public health threat. This study aimed to assess the nasopharyngeal carriage of S. aureus in poultry and to investigate antimicrobial susceptibility and virulence-associated genes. Nasopharyngeal swabs were collected from chickens at the slaughterhouse of Tangier and immediately transported to the microbiological laboratory for phenotypic identification and assessment of antibiotic susceptibility. The presence of 16S rRNA, nuc, mecA, mecC, Panton–Valentine leukocidin (PVL), and the toxic shock syndrome toxin 1 (TSST-1) genes were detected by PCR analysis for all isolates. Overall, 548 nasopharyngeal swabs were collected, of which 17 (3.4%) were S. aureus positive. More than half of the strains (54%) were resistant to penicillin, 29.4% to tetracycline, 23.5% to erythromycin, and 17% showed resistance to ciprofloxacin. The mecA and mecC were not identified in any of the recovered isolates. Of the S. aureus recovered, 29.41% of the isolates were found to be toxinogenic; 17.64% and 11.76% were positive for PVL and TSST-1 encoding genes, respectively. The trends of antibiotic resistance and the toxinogenic S. aureus carried by the poultry intended for consumption in Tangier present a huge concern. Preventive and containment measures should be implemented in order to limit the dissemination of resistance genes through the food chain and to reduce their increased rate.

Using Green Sea Turtles ( Chelonia mydas ) as Essential Bio‐indicators for Monitoring Antibiotic Resistance in Marine Environments Worldwide: A Critical Appraisal

The development and environmental transmission of antibiotic resistance (ABR) pathogens is of global public health concern. In marine environments, this problem is associated at least in part, with pollution due to anthropogenic activities such as discharging wastewater and industrial waste run-off. Herein we systematically reviewed and evaluated the incidence of ABR identified in Green sea turtles and their propensity to be used as bio-indicators for monitoring ABR in marine environments because of their highly migratory nature and reliance on sea vegetation. ABR was identified using standard culture and sensitivity tests; quantitatively represented as percentages of confirmed bacterial isolates. Studied sites to date are represented by clusters in the Arabian Sea and the Pacific and Atlantic oceans; frequencies of identified multidrug resistant bacteria (MDRB) were: 78 ± 16%, 42 ± 13% and 16% respectively. Antimicrobials of the beta-lactam class were associated with the highest cumulative frequency of resistance (103%) compared to quinonolones (31%) and aminoglycosides (30%) across all sites. This data seems to reflect concerted, global efforts to reserve and minimise the use of aminoglycosides and quinolones. These ABR patterns mirror trends in the use of antibiotics in anthropogenic activities generally. However, there is a need to establish direct associations between ABR in sea turtles with wastewater and other anthropogenic activities in marine environments worldwide.

Antibiotic Resistance in Wastewater Treatment Plants and Transmission Risks for Employees and Residents: The Concept of the AWARE Study.

Antibiotic resistance has become a serious global health threat. Wastewater treatment plants may become unintentional collection points for bacteria resistant to antimicrobials. Little is known about the transmission of antibiotic resistance from wastewater treatment plants to humans, most importantly to wastewater treatment plant workers and residents living in the vicinity. We aim to deliver precise information about the methods used in the AWARE (Antibiotic Resistance in Wastewater: Transmission Risks for Employees and Residents around Wastewater Treatment Plants) study. Within the AWARE study, we gathered data on the prevalence of two antibiotic resistance phenotypes, ESBL-producing E. coli and carbapenemase-producing Enterobacteriaceae, as well as on their corresponding antibiotic resistance genes isolated from air, water, and sewage samples taken from inside and outside of different wastewater treatment plants in Germany, the Netherlands, and Romania. Additionally, we analysed stool samples of wastewater treatment plant workers, nearby residents, and members of a comparison group living ≥1000 m away from the closest WWTP. To our knowledge, this is the first study investigating the potential spread of ESBL-producing E. coli, carbapenemase-producing Enterobacteriaceae, and antibiotic resistance genes from WWTPs to workers, the environment, and nearby residents. Quantifying the contribution of different wastewater treatment processes to the removal efficiency of ESBL-producing E. coli, carbapenemase-producing Enterobacteriaceae, and antibiotic resistance genes will provide us with evidence-based support for possible mitigation strategies.

Application of manure from cattle administered antibiotics has sustained multi-year impacts on soil resistome and microbial community structure

In agroecosystems, application of manure from livestock treated with antibiotics has the potential to spread antibiotic compounds, resistant bacteria, and antibiotic resistance genes (ARGs) to soil. Although environmental transmission of antibiotic resistance is a major human health concern, few studies have looked at long-term effects on soil microbial communities from applying manure from livestock administered antibiotics. We examined the impacts of three years of repeated manure additions from cattle under different antibiotic treatments on microbial community structure and ARG abundances. While manure additions altered both soil bacterial and fungal communities, manure from cattle administered antibiotics further altered soil bacterial communities, but not fungal, compared to manure from antibiotic-free cattle. Furthermore, addition of manure from antibiotic-free cattle resulted in increased abundances of several ARGs compared to soil with no manure inputs, but manure from cattle administered antibiotics did not change overall profiles of ARG abundances compared to manure from antibiotic-free cattle. Finally, although bacterial and fungal community structure and ARG abundances varied among years, manure treatment effects on each were persistent during the full three-year period. Taken together, our results suggest that manure and antibiotic impacts on soil microbial communities can persist for long periods of repeated manure application. Furthermore, soil management strategies for addressing the antibiotic resistance crisis should consider the broader context of manure management.

Human Colonization with Extended-Spectrum Beta-Lactamase-Producing E. coli in Relation to Animal and Environmental Exposures in Bangladesh: An Observational One Health Study.

Background:Human exposure to intensively farmed livestock is a potential risk for transmission of antibiotic-resistant bacteria (ARB) but few studies have assessed the relative role of animal vs. environmental sources of ARB in low-resource community settings.Objectives:We conducted an observational study to compare ARB colonization and antibiotic-resistant gene prevalence and abundance in humans with high or low exposure to poultry in rural households, commercial poultry farms, and urban markets in Bangladesh.Methods:Extended-spectrum (ESBL)-producing and carbapenem-resistant E. coli were quantified in feces from adults with high or low poultry exposure (, respectively), poultry (), drinking water (), and wastewater () from 40 rural households, 40 poultry farms, and 40 urban markets.Results:ESBL-producing E. coli (ESBL-EC) prevalence was 67.5% (95% CI: 61.0, 74.0) in samples from adults, 68.0% (95% CI: 61.5, 74.5) in samples from poultry, and 92.5% (95% CI: 87.7, 97.3) in wastewater samples. Carbapenem-resistant E. coli prevalence was high in market wastewaters [30% (95% CI: 15.0, 45.0)] but low in humans (1%) and poultry (1%). Human, poultry, and wastewater isolates shared common resistance genes: , qnr, and . Human colonization was not significantly associated with exposure to poultry or setting (rural, farm, or market). Ninety-five percent of commercial poultry farms routinely administered antibiotics. Susceptibility tests were significantly different in household vs. farm and market poultry isolates for four of seven antibiotic classes. In human isolates, there were no differences except aminoglycoside resistance (16.4% high vs. 4.4% low exposure, ). Urban market wastewaters and poultry samples had significantly higher concentrations of ESBL-EC () and () compared with samples from farms and rural households.Discussion:ESBL-EC colonization was high in humans but not significantly associated with exposure to poultry. Bidirectional transmission of antibiotic resistance is likely between humans, poultry, and the environment in these community settings, underlining the importance of One Health mitigation strategies. https://doi.org/10.1289/EHP7670

Polyphasic characterization of carbapenem-resistant Klebsiella pneumoniae clinical isolates suggests vertical transmission of the blaKPC-3 gene.

Carbapenem-resistant Klebsiella pneumoniae are a major global threat in healthcare facilities. The propagation of carbapenem resistance determinants can occur through vertical transmission, with genetic elements being transmitted by the host bacterium, or by horizontal transmission, with the same genetic elements being transferred among distinct bacterial hosts. This work aimed to track carbapenem resistance transmission by K. pneumoniae in a healthcare facility. The study involved a polyphasic approach based on conjugation assays, resistance phenotype and genotype analyses, whole genome sequencing, and plasmid characterization by pulsed field gel electrophoresis and optical DNA mapping. Out of 40 K. pneumoniae clinical isolates recovered over two years, five were carbapenem- and multidrug-resistant and belonged to multilocus sequence type ST147. These isolates harboured the carbapenemase encoding blaKPC-3 gene, integrated in conjugative plasmids of 140 kbp or 55 kbp, belonging to replicon types incFIA/incFIIK or incN/incFIIK, respectively. The two distinct plasmids encoding the blaKPC-3 gene were associated with distinct genetic lineages, as confirmed by optical DNA mapping and whole genome sequence analyses. These results suggested vertical (bacterial strain-based) transmission of the carbapenem-resistance genetic elements. Determination of the mode of transmission of antibiotic resistance in healthcare facilities, only possible based on polyphasic approaches as described here, is essential to control resistance propagation.

Distribution of TET, AAC and CTX-M Genes among Antibiotic Resistant Escherichia coli Isolated From Poultry under Various Farming System of A and N Islands

Background: Transmission of antibiotic resistance from animal food chain to human through animal food-borne pathogens have led to increased public concern. Wider surveillance on prevalence of antibiotic resistance in E. coli will provide information on evolution of resistance in various geographical locations. The purpose of this study was to investigate the presence of antimicrobial resistance of E. coli isolates from poultry under various farming system in A and N Islands and resistance genes of tet, ctx-M and aac encoding the isolates. Methods: Isolates were obtained from cloacal swabs in poultry under various farming systems and tested against major antimicrobial derivatives to study multi drug resistance. The presence of genes associated with resistance to tetracycline (tet A), ESBL (CTX-M) and Gentamycin (aac(3)-IV) were determined by PCR. Result: A total of 126 cloacal samples were analysed out of which 31.38% of the E.coli isolates from poultry under various farming systems were producing extended spectrum beta-lactamases and were multiple antimicrobial resistant. Poultry birds of commercial farms showed higher resistance levels (37.5%) than organised farms (24.76%) and desi birds (31.88%). Results indicate a high level of multi-drug resistance is emerging even in desi birds. It is suggested that an antimicrobial resistance surveillance program is needed in A and N Islands in order to detect bacterial resistance among rural poultry production as the 80 percentage of total poultry population belong to desi birds.

Suggestions for Management and Control of Antibiotics in Farmland Soil in China

Antibiotics are important for sustaining the livestock and poultry industry in China; however, duo to the agricultural utilization of livestock and poultry manure, the risk of antibiotic resistance transmission becomes increasingly prominent. Therefore, the risk control of antibiotics and antibiotic resistance genes in the farmland soil becomes urgent in China. In this study, we summarizes the status of antibiotic pollution in the farmland soil in China, sorts out the problems regarding the management and control of emerging antibiotic pollutants in farmland soil, and proposes some measures for risk control of the antibiotics and antibiotic resistance genes. This study reveals that the emerging antibiotic pollutants have not been included in soil risk management and more attention should be paid to the pollution risks of the antibiotics and antibiotic resistance genes for the farmland soil. To this end, a strict veterinary drug regulatory mechanism should be established to control the risks from the source. Moreover, standards should be established for controlling antibiotic resistance in organic fertilizers, and technical guidelines should be created for regulating the treatment and application of antibiotics-containing manure, thus to reduce the amount of antibiotic resistance genes that enter into the environment. Meanwhile, human health risks caused by the generation and transfer of environmental antibiotic resistance should be assessed and studied and routine monitoring of antibiotic resistance in farmland soil should be conducted, thereby supporting the risk control of such pollutants using risk assessment.