Source Of Antibiotic Resistance Research Articles

Distribution of Antibiotic Resistance in a Mixed-Use Watershed and the Impact of Wastewater Treatment Plants on Antibiotic Resistance in Surface Water.

The aquatic environment has been recognized as a source of antibiotic resistance (AR) that factors into the One Health approach to combat AR. To provide much needed data on AR in the environment, a comprehensive survey of antibiotic-resistant bacteria (ARB), antibiotic resistance genes (ARGs), and antibiotic residues was conducted in a mixed-use watershed and wastewater treatment plants (WWTPs) within the watershed to evaluate these contaminants in surface water. A culture-based approach was used to determine prevalence and diversity of ARB in surface water. Low levels of AR Salmonella (9.6%) and Escherichia coli (6.5%) were detected, while all Enterococcus were resistant to at least one tested antibiotic. Fewer than 20% of extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae (17.3%) and carbapenem-resistant Enterobacteriaceae (CRE) (7.7%) were recovered. Six ARGs were detected using qPCR, primarily the erythromycin-resistance gene, ermB. Of the 26 antibiotics measured, almost all water samples (98.7%) had detectable levels of antibiotics. Analysis of wastewater samples from three WWTPs showed that WWTPs did not completely remove AR contaminants. ARGs and antibiotics were detected in all the WWTP effluent discharges, indicating that WWTPs are the source of AR contaminants in receiving water. However, no significant difference in ARGs and antibiotics between the upstream and downstream water suggests that there are other sources of AR contamination. The widespread occurrence and abundance of medically important antibiotics, bacteria resistant to antibiotics used for human and veterinary purposes, and the genes associated with resistance to these antibiotics, may potentially pose risks to the local populations exposed to these water sources.

Novel, non-colonizing, single-strain live biotherapeutic product ADS024 protects against Clostridioides difficile infection challenge in vivo.

The Centers for Disease Control and Prevention estimate that Clostridioides difficile (C. difficile) causes half a million infections (CDI) annually and is a major cause of total infectious disease death in the United States, causing inflammation of the colon and potentially deadly diarrhea. We recently reported the isolation of ADS024, a Bacillus velezensis (B. velezensis) strain, which demonstrated direct in vitro bactericidal activity against C. difficile, with minimal collateral impact on other members of the gut microbiota. In this study, we hypothesized that in vitro activities of ADS024 will translate in vivo to protect against CDI challenge in mouse models. To investigate the in vivo efficacy of B. velezensis ADS024 in protecting against CDI challenge in mouse models. To mimic disruption of the gut microbiota, the mice were exposed to vancomycin prior to dosing with ADS024. For the mouse single-dose study, the recovery of ADS024 was assessed via microbiological analysis of intestinal and fecal samples at 4 h, 8 h, and 24 h after a single oral dose of 5 × 108 colony-forming units (CFU)/mouse of freshly grown ADS024. The single-dose study in miniature swine included groups that had been pre-dosed with vancomycin and that had been exposed to a dose range of ADS024, and a group that was not pre-dosed with vancomycin and received a single dose of ADS024. The ADS024 colonies [assessed by quantitative polymerase chain reaction (qPCR) using ADS024-specific primers] were counted on agar plates. For the 28-d miniature swine study, qPCR was used to measure ADS024 levels from fecal samples after oral administration of ADS024 capsules containing 5 × 109 CFU for 28 consecutive days, followed by MiSeq compositional sequencing and bioinformatic analyses to measure the impact of ADS024 on microbiota. Two studies were performed to determine the efficacy of ADS024 in a mouse model of CDI: Study 1 to determine the effects of fresh ADS024 culture and ADS024 spore preparations on the clinical manifestations of CDI in mice, and Study 2 to compare the efficacy of single daily doses vs dosing 3 times per day with fresh ADS024. C. difficile challenge was performed 24 h after the start of ADS024 exposure. To model the human distal colon, an anerobic fecal fermentation system was used. MiSeq compositional sequencing and bioinformatic analyses were performed to measure microbiota diversity changes following ADS024 treatment. To assess the potential of ADS024 to be a source of antibiotic resistance, its susceptibility to 18 different antibiotics was tested. In a mouse model of CDI challenge, single daily doses of ADS024 were as efficacious as multiple daily doses in protecting against subsequent challenge by C. difficile pathogen-induced disease. ADS024 showed no evidence of colonization based on the observation that the ADS024 colonies were not recovered 24 h after single doses in mice or 72 h after single doses in miniature swine. In a 28-d repeat-dose study in miniature swine, ADS024 was not detected in fecal samples using plating and qPCR methods. Phylogenetic analysis performed in the human distal colon model showed that ADS024 had a selective impact on the healthy human colonic microbiota, similarly to the in vivo studies performed in miniature swine. Safety assessments indicated that ADS024 was susceptible to all the antibiotics tested, while in silico testing revealed a low potential for off-target activity or virulence and antibiotic-resistance mechanisms. Our findings, demonstrating in vivo efficacy of ADS024 in protecting against CDI challenge in mouse models, support the use of ADS024 in preventing recurrent CDI following standard antibiotic treatment.

Overview of the Risks of Antibiotic Contamination of Dairy Products

Antibiotics are widely used in animal husbandry for livestock treatment, as well as in feed additives, as growth promoters. Antibiotics are sometimes used to preserve food and extend shelf life in the food industry. One can often encounter the falsification of agricultural raw materials and finished products with antibiotics for the same purposes. Antibiotics can get into food through animals. Milk and dairy products occupy an important place among food products; they are especially necessary for the younger generation. Currently, antibiotics are considered a serious factor in the contamination of food products, as well as a source of antibiotic resistance and food allergies. The international community is concerned about the problem associated with the steady development of pathogenic microorganisms’ resistance to the drugs currently in use. According to expert estimates, about 700 thousand people die every year globally due to the resistance of pathogenic microorganisms. As a result, the problem of negative impact of antibiotics on humans becomes crucial. Different countries, the WHO, the WTO, and the EAEU, which includes the Russian Federation, adopt regulations and special laws that limit the use of antibiotics in the agro-industrial complex. Therefore, the problem of studying the risks of contamination of food and dairy products with antibiotics is a pressing matter.

Occurrence and Characteristics of Staphylococcus aureus Strains along the Production Chain of Raw Milk Cheeses in Poland.

Cheeses produced from unpasteurized milk by traditional production methods may contain many groups of microorganisms, including Staphylococcus aureus. The aim of this study was to determine the occurrence of S. aureus in the artisanal cheese production chain from unpasteurized milk. We investigated the prevalence of S. aureus strains isolated from various stages of artisanal cheese of unpasteurized milk production from farms in the northeastern and southern parts of Poland and characterized them. Characterization included antimicrobial susceptibility by microbroth dilution and biofilm formation by in vitro assay. Among all strains, the presence of enterotoxigenic genes and genes involved with biofilm formation and antibiotic resistance were screened by PCR-based methods. A total of 180 samples were examined. A high percentage of strains were resistant to penicillin (54/58.1%) and tobramycin (32/34.4%). Some tested isolates also showed resistance to the macrolide class of antibiotics: azithromycin, clarithromycin, and erythromycin at 17/18.3%, 15/16.1%, and 21/22.6%, respectively. Among tested isolates, we also found phenotypic resistance to oxacillin (9/9.7%) and cefoxitin (12/12.9%). The blaZ gene encoding penicillin resistance was the most common gene encoding antibiotic resistance among the tested strains. All isolates showing phenotypic resistance to cefoxitin possessed the mecA gene. The study also evaluated the prevalence of biofilm-associated genes, with eno the most frequently associated gene. Eighty-nine out of 93 S. aureus isolates (95.7%) possessed at least one enterotoxin-encoding gene. The results of this study showed that production of raw milk cheeses may be a source of antibiotic resistance and virulent S. aureus. Our results suggest that artisanal cheese producers should better control production hygiene.

Dynamics of Genotypic and Phenotypic Antibiotic Resistance in a Conventional Wastewater Treatment Plant in 2 Years.

Wastewater treatment plants (WWTPs) are considered a sink and a source of antibiotic resistance. In this study, we applied both culture-dependent and SmartChip-based culture-independent approaches for the investigation of antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs) at Jungnang (JN), located in the Han River, Seoul, South Korea, for 2 years, i.e., 2017 and 2018. The JN WWTP reduced the diversity and abundance of ARB and ARGs but was not sufficient for removing them all. Interestingly, through the treatment process in the JN WWTP, the composition of diverse multidrug-resistant (MDR) bacteria was concentrated mainly into some genera of the Gammaproteobacteria class (Citrobacter, Escherichia-Shigella, and Stenotrophomonas), which could be key carriages to spread ARGs into the environments. In addition, SmartChip analyses showed that the relative abundance and the number of ARGs were significantly decreased from the influents to the effluents in both 2017 and 2018. SmartChip analyses for 2 years also allowed to notify the core ARGs in the influents and the effluents with the presence of clinically relevant core ARGs, such as vanC, blaOXA, and blaNDM, which persisted in the treatment process. Considering diverse bacterial mechanisms for exchanging and transferring ARGs, the occurrence of MDR bacteria and core ARGs could be a source for the blooming of the antibiotic resistome in the WWTP and nearby environments.

Proteomic Network of Antibiotic-Induced Outer Membrane Vesicles Released by Extensively Drug-Resistant Elizabethkingia anophelis.

ABSTRACTElizabethkingia anophelis, a nonfermenting Gram-negative bacterium, causes life-threatening health care-associated infections. E. anophelis harbors multidrug resistance (MDR) genes and is intrinsically resistant to various classes of antibiotics. Outer membrane vesicles (OMVs) are secreted by Gram-negative bacteria and contain materials involved in bacterial survival and pathogenesis. OMVs specialize and tailor their functions by carrying different components to challenging environments and allowing communication with other microorganisms or hosts. In this study, we sought to understand the characteristics of E. anophelis OMVs under different antibiotic stress conditions. An extensively drug-resistant clinical isolate, E. anophelis C08, was exposed to multiple antibiotics in vitro, and its OMVs were characterized using nanoparticle tracking analysis, transmission electron microscopy, and proteomic analysis. Protein functionality analysis showed that the OMVs were predominantly involved in metabolism, survival, defense, and antibiotic resistance processes, such as the Rag/Sus family, the chaperonin GroEL, prenyltransferase, and an HmuY family protein. Additionally, a protein-protein interaction network demonstrated that OMVs from imipenem-treated E. anophelis showed significant enrichments in the outer membrane, adenyl nucleotide binding, serine-type peptidase activity, the glycosyl compound metabolic process, and cation binding proteins. Collectively, the OMV proteome expression profile indicates that the role of OMVs is immunologically relevant and related to bacterial survival in antibiotic stress environments rather than representing a resistance point.IMPORTANCE Elizabethkingia anophelis is a bacterium often associated with nosocomial infection. This study demonstrated that imipenem-induced E. anophelis outer membrane vesicles (OMVs) are immunologically relevant and crucial for bacterial survival under antibiotic stress conditions rather than being a source of antibiotic resistance. Furthermore, this is the first study to discuss the protein-protein interaction network of the OMVs released by E. anophelis, especially under antibiotic stress. Our findings provide important insights into clinical antibiotic stewardship.

Worldwide Prevalence of mcr-mediated Colistin-Resistance Escherichia coli in Isolates of Clinical Samples, Healthy Humans, and Livestock-A Systematic Review and Meta-Analysis.

Background: Antimicrobial resistance is a serious public-health problem throughout the world. Escherichia coli, the most common Gram-negative microorganism, has developed different resistance mechanisms, making treating infections difficult. Colistin is considered a last-resort drug in the treatment of infections caused by E. coli. Plasmid-mediated mobile-colistin-resistant (mcr) genes in E. coli, now disseminated globally, are considered a major public-health threat. Humans, chickens, and pigs are the main reservoirs for E. coli and the sources of antibiotic resistance. Hence, an up-to-date and precise estimate of the global prevalence of mcr resistance genes in these reservoirs is necessary to understand more precisely the worldwide spread and to more effectively implement control and prevention strategies. Methodology: Publications were identified in the PubMed database on the basis of the PRISMA guidelines. English full-text articles were selected from December 2014 to March 2021. Descriptive statistics and a meta-analysis were performed in Excel and R software, respectively. Colistin resistance was defined as the molecular-genetic detection of the mcr genes. The crude and estimated prevalence were calculated for each host and continent. The studies were divided into two groups; community-based when they involved isolates from healthy humans, chickens, or pigs, and clinical studies when they involved only hospital, outpatient, or laboratory isolates. Results: A total of 1278 studies were identified and 218 were included in this systematic review and meta-analysis, divided into community studies (159 studies) and clinical studies (59 studies). The general prevalence of mcr-mediated colistin-resistant E. coli (mcrMCRE) was 6.51% (n = 11,583/177,720), reported in 54 countries and on five continents; Asia with 119 studies followed by Europe with 61 studies registered the most articles. Asia reported the major diversity of mcr-variants (eight of nine, except mcr-2). Worldwide, chickens and pigs proved to be the principal reservoir of mcr with an estimated prevalence of 15.8% and 14.9%, respectively. Healthy humans and clinical isolates showed a lower prevalence with 7.4% and 4.2% respectively. Conclusions: In this systematic review and meta-analysis, the worldwide prevalence of mcr in E. coli isolated from healthy humans, chickens, and pigs was investigated. A wide prevalence and distribution of mcr genes was demonstrated on all continents in E. coli isolates from the selected reservoirs. Understanding the epidemiology and occurrence in the reservoirs of mcr in E. coli on different continents of the world facilitates tracing how mcr genes are transmitted and determining the infection risks for humans. This knowledge can be used to reduce the incidence of zoonotic transmission by implementing the appropriate control programs.

Antimicrobial Resistance and Comparative Genome Analysis of Klebsiella pneumoniae Strains Isolated in Egypt

Klebsiella pneumoniae is an important human pathogen in both developing and industrialised countries that can causes a variety of human infections, such as pneumonia, urinary tract infections and bacteremia. Like many Gram-negative bacteria, it is becoming resistant to many frontline antibiotics, such as carbapenem and cephalosporin antibiotics. In Egypt, K. pneumoniae is increasingly recognised as an emerging pathogen, with high levels of antibiotic resistance. However, few Egyptian K. pneumoniae strains have been sequenced and characterised. Hence, here, we present the genome sequence of a multidrug resistant K. pneumoniae strain, KPE16, which was isolated from a child in Assiut, Egypt. We report that it carries multiple antimicrobial resistance genes, including a blaNDM-1 carbapenemase and extended spectrum β-lactamase genes (i.e., blaSHV-40, blaTEM-1B, blaOXA-9 and blaCTX-M-15). By comparing this strain with other Egyptian isolates, we identified common plasmids, resistance genes and virulence determinants. Our analysis suggests that some of the resistance plasmids that we have identified are circulating in K. pneumoniae strains in Egypt, and are likely a source of antibiotic resistance throughout the world.

Animal source food eating habits of outpatients with antimicrobial resistance in Bukavu, D.R. Congo

BackgroundAntibiotic resistance is a public health concern in Democratic Republic Congo and worldwide. It is usually caused by antibiotic over prescription or dispensing practices. The consumption of animal source food (ASF) could be another source of antibiotic resistance but is rarely studied. The objective of the study was to evaluate the eating habits of ASF by outpatients with antimicrobial resistance through an analysis of (i) the association of their antimicrobial resistance with ASF consumption; (ii) the influence of the types of ASF on their antimicrobial resistance. MethodsThis is a retrospective analytical study conducted at three major Hospitals in Bukavu City (D. R. Congo). A total number of 210 patients, whose samples (mainly faeces and urine) had been subjected to bacterial examination, was included in this study. Morphological, biochemical and antibiotic susceptibility (using disc diffusion method) tests were performed on the samples. This served to isolate and identify resistant bacteria. Afterwards, patients responded to questions about the types and quantity of ASF eaten in the last week. We analysed data using descriptive statistics, logistic regression and non-parametric ranking tests.ResultsEscherichia coli (37.1%), Klebsiella pneumonae (14.7%), and Staphylococcus aureus (13.8%) were the most prevalent bacteria. E. coli (68.4%) and K. pneumonae (87.5%) were multidrug resistant (MDR), while S. aureus (7.7%) was minor. Low beef (O.R. 0.737, C.I. 0.542–1.002) and pork (O.R. 0.743, C.I. 0.560 – 0.985) consumption led to significantly (p < 0.05) lower risks of resistance to ciprofloxacin. Patients eating three different ASF per week had the highest resistance score (20.67) and high consumption rates of goat meat, pork and milk (41.5%).ConclusionThe findings of this study suggest a contribution of human nutrition to antimicrobial resistance frequency. Our results show the existence of a high prevalence of multi-drug resistant bacteria in patients for which eating beef, pork and drinking milk are major risk factors. Therefore, a stricter control of antibiotic usage in livestock production and of their presence in ASF is recommended.

Antibiotic Resistance and Phylogeny of Pseudomonas spp. Isolated over Three Decades from Chicken Meat in the Norwegian Food Chain.

Pseudomonas is ubiquitous in nature and a predominant genus in many foods and food processing environments, where it primarily represents major food spoilage organisms. The food chain has also been reported to be a potential reservoir of antibiotic-resistant Pseudomonas. The purpose of the current study was to determine the occurrence of antibiotic resistance in psychrotrophic Pseudomonas spp. collected over a time span of 26 years from retail chicken in Norway and characterize their genetic diversity, phylogenetic distribution and resistance genes through whole-genome sequence analyses. Among the 325 confirmed Pseudomonas spp. isolates by 16S rRNA gene sequencing, antibiotic susceptibility profiles of 175 isolates to 12 antibiotics were determined. A subset of 31 isolates being resistant to ≥3 antibiotics were whole-genome sequenced. The isolates were dominated by species of the P. fluorescens lineage. Isolates susceptible to all antibiotics or resistant to ≥3 antibiotics comprised 20.6% and 24.1%, respectively. The most common resistance was to aztreonam (72.6%), colistin (30.2%), imipenem (25.6%) and meropenem (12.6%). Resistance properties appeared relatively stable over the 26-year study period but with taxa-specific differences. Whole-genome sequencing showed high genome variability, where isolates resistant to ≥3 antibiotics belonged to seven species. A single metallo-betalactmase gene (cphA) was detected, though intrinsic resistance determinants dominated, including resistance–nodulation (RND), ATP-binding cassette (ABC) and small multidrug resistance (Smr) efflux pumps. This study provides further knowledge on the distribution of psychrotrophic Pseudomonas spp. in chicken meat and their antibiotic resistance properties. Further monitoring should be encouraged to determine food as a source of antibiotic resistance and maintain the overall favorable situation with regard to antibiotic resistance in the Norwegian food chain.

Antibiotic Resistance Phenotypes among Escherichia coli Isolated from Sachet and Pipe-Borne Water from Selected Local Government Areas of Kaduna State, Nigeria

The presence of coliform bacteria such as Escherichia coli (E. coli) in water used for drinking is of great public health concern due to the risk it poses to consumers. This risk is exacerbated when the bacteria are resistant to commonly used antibiotics. This study aimed at determining the antibiotic resistant phenotypes among E. coli isolated from sachet water (Pure water) and municipal pipe-borne water in selected local government areas of Kaduna state, Nigeria. A total of 105 water samples (69 sachet water and 36 municipal pipe-borne water) were subjected to bacterial isolation following standard methods and the isolated E. coli were subjected to antibiotic susceptibility testing to ten (10) commonly used antibiotics. The isolation rates of the organism were 14.4% and 22.9% in sachet and pipe-borne water respectively. The isolates were all (100%) susceptible to gentamicin, and also showed high susceptibility to amoxicillin-clavulanic acid (83.3%), chloramphenicol (94.5%), cefotaxime (94.5%) and sulphamethoxazole - trimethoprim (100%). On the other hand, 9 isolates (50%) showed various resistance patterns with 3 isolates being resistant to up to seven (7) antibiotics, with resistance patterns TE, NA, C, CIP, CTX, AMP, AML and TE, NA, AMC, SXT, CIP, AMP, AML. Eight out of the 9 resistant isolates showed resistance to Nalidixic acid and 7 showed resistance to Tetracycline. These results indicate that drinking water in the study area is a source of antibiotic resistance. It is obvious that more attention needs to be focused on ensuring the safety and potability of drinking water in the study area.&#x0D;

ANTIBIOTIC RESISTANCE IN BACTERIAL PATHOGENS ISOLATED FROM CATTLE DUNG AND ITS CONTAMINATED SOIL

&#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; Cattle dung is used as organic fertilizer and alternative source of fuel or biogas but could also be a source of antibiotic resistance genes in the environment. This study isolated, identified and assessed antibiotic susceptibility pattern of bacteria from cattle dung and its contaminated soil. Bacteria isolation and identification were based on standard techniques while hemolytic activity was used to confirm potential pathogenic bacteria. Antibiotic susceptibility pattern of isolated pathogens were assayed by disk diffusion method. Among isolated bacteria, Staphylococcus spp had highest occurrence of 23.8 % while Micrococcus spp was the least at 1.3 %. Hemolytic bacteria isolates were Staphylococcus aureus (16.5 %), Bacillus spp (17.4 %), Nocardia spp (4.6 %), Escherichia coli (29.4 %), Pseudomonas spp (13.8 %), Serratia marcersens (2.8 %) and Salmonella spp (15.6 %). High resistance (100 %) against Ampiclox (30 µg) was observed in all Staphylococcus aureus and Bacillus spp isolates while Pseudomonas aeruginosa isolates showed 100 % resistance to Ofloxacin (30 µg). Most Gram-positive bacterial isolates were majorly resistant to Beta lactams while Gram negative bacteria were resistant to Fluoroquinolones antibiotics. Multiple antibiotics resistant index (MARI) was measured at greater than 0.2, and was observed in 71.5 % of the hemolytic pathogens. Antibiotics resistance in hemolytic bacterial pathogens from this study is indicative of environmental sources of antibiotic resistance and possible adverse effects on human health.

Association of carvacrol with ceftazidime and cefepime against Klebsiella pneumoniae

Klebsiella pneumoniae is an important opportunistic pathogen responsible for considerable rates of nosocomial infections. In addition, this species is an important source of antibiotic resistance, presenting a great capacity to acquire plasmids with genes that give them resistance to multiple antibacterials, which makes it necessary to develop therapeutic alternatives. The combination of phytochemicals and classic drugs has been shown to be beneficial. Based on this, this study aimed to investigate the potential use of carvacrol in combination with the antibacterials classically used in clinical practice ceftazidime and cefepime, in order to optimize the treatment of these infections. The association was carried out using the checkerboard method. The observed result for 100% of the strains analyzed was an additive effect in the combination of carvacrol with ceftazidime and carvacrol with cefepime. Thus, carvacrol has potential use as an adjunct in the treatment of infections caused by K. pneumoniae in combination with ceftazidime and cefepime, due to the additive effect shown in the combination with both drugs. Structural changes can be made to improve this observed effect. This research opens perspectives for more studies that aim to analyze the effects of the combination of carvacrol with other antibacterial drugs.

Prevalence of qnrVC Genes in Pseudomonas aeruginosa Clinical Isolates from Guangdong, China.

Pseudomonas aeruginosa is a serious nosocomial pathogen with high morbidity and mortality due to the increasing resistance to antibiotics in recent years. qnrVC genes have been proven as a source of antibiotic resistance, but relationship with Pseudomonas aeruginosa remains not clear. We aimed to investigate the prevalence and molecular characteristics of qnrVC genes in P. aeruginosa clinical isolates. A total of 874 nonduplicate clinical isolates were collected in Guangdong, China, between January 2011 and June 2015. The presence of qnrVC genes and their genotypes were determined using PCR amplification and DNA sequencing. Antibiotic susceptibilities were tested, and the genetic relatedness of qnrVC-positive isolates were analyzed by multi-locus sequence typing (MLST) and pulsed field gel electrophoresis (PFGE). Consequently, we found 2.3% of P. aeruginosa isolates were present with qnrVC genes, displaying more resistant to various antibiotics. Phylogenetic analysis of qnrVC-positive strains revealed that antibacterial resistance among qnrVC-positive P. aeruginosa isolates in Guangdong probably emerged from multiple sources and was not spread by clonal strains.

Occurrence Of The Co-Selection Phenomenon In Non-Clinical Environments

Abstract Multi-resistant bacterial strains currently present the main health problem worldwide. Numerous public health organizations call for the prevention, and control the spread, of antibiotic resistance from any sources. From the literature data, it is well known that agricultural areas are a source of antibiotic resistance because of the use of antibiotics and heavy metals to promote plant and animal growth. Moreover, natural water reservoirs and soil not used for agriculture are also sources of multi-drug resistant bacteria. In recent years bacteria resistant to antibiotics and heavy metals have been isolated from heavy-metal contaminated soils and from metallophytes. Therefore, it seems that heavy metals, an environmental pollutant, may also be a selection factor that promotes the spread of antibiotic resistance. The co-selection phenomenon of resistant genes is most often connected with the lack of bacterial susceptibility to antibiotics and heavy metals. Co-selection occurs when different resistant genes that enable resistance to different stress conditions are located on the same mobile genetic elements, or when the same genes determine resistance to different stress conditions. This article presents the current state of knowledge about the co-selection phenomenon observed in bacteria isolated from nonclinical environments. 1. Introduction. 2. Co-selection mechanisms. 2.1. Cross-resistance. 2.2. Co-resistance. 2.3. Co-regulation. 3. Factors promoting spread of co-selection. 4. Occurrence of co-selection in non-clinical environments. 4.1. Areas used for agriculture. 4.2. Areas not used agriculturally. 4.3. Natural water reservoirs. 4.4. Plant endosphere. 5. Co-occurence of resistant genes in different environmental genomes. 6. Summary

Association Between Antibiotic Resistance and Integron Class2 Among Commonsal Escherichia coli Genotypic Groups

Antibiotic therapies can not affect only on the pathogenic bacteria, but also commensal microorganisms in the humans gut, which might serve as a reservoir of antimicrobial resistance genes. fecal Escherichia coli (E. coli) is often considered as a good indicator for selection pressure imposed by antimicrobial use. The goal of this study was to determine genotyping groups of commonsal E. coli and investigate the frequency of integrons class 2 and antibiotic resistance among them. So detect the association of integron class2 with antibiotic resistance (single and multiple drug resistance) that may be transport horizontally in bacterial populations. In this study 301isolates of commonsal E. coli were isolated from stools obtained from healthy individuals with age from 1to 80 years. All isolates were tested for their susceptibility against 16 antimicrobial agents and subjected to conventional polymerase chain reactions (PCR) for detection integrons and multiplex PCR for genotyping analysis. Present results showed that group B2 represent the majority of the collected isolates&#x0D; (63%) followed by group A (23%) and D (14%) but no strains were found to belong to group B1. Also results revealed that 10% of isolates have integron class 2 that mainly related to genotypic group B2. High resistance observed for most antibiotics especially ampicilln, amoxcillin, lincomycin, cephalexin while resistance to amikacin and gentamicin was less common. Antibiotic resistance mainly appeared in integron positive isolates. In conclusion, high prevalence of antibiotic resistance especially among integron class 2 positive isolates that indicated role of gut flora as reservoir and source of antibiotic resistance. &#x0D; Antibiotic therapies can not affect only on the pathogenic bacteria, but also commensal microorganisms in the humans gut, which might serve as a reservoir of antimicrobial resistance genes. fecal Escherichia coli (E. coli) is often considered as a good indicator for selection pressure imposed by antimicrobial use. The goal of this study was to determine genotyping groups of commonsal E. coli and investigate the frequency of integrons class 2 and antibiotic resistance among them. So detect the association of integron class2 with antibiotic resistance (single and multiple drug resistance) that may be transport horizontally in bacterial populations. In this study 301isolates of commonsal E. coli were isolated from stools obtained from healthy individuals with age from 1to 80 years. All isolates were tested for their susceptibility against 16 antimicrobial agents and subjected to conventional polymerase chain reactions (PCR) for detection integrons and multiplex PCR for genotyping analysis. Present results showed that group B2 represent the majority of the collected isolates&#x0D; (63%) followed by group A (23%) and D (14%) but no strains were found to belong to group B1. Also results revealed that 10% of isolates have integron class 2 that mainly related to genotypic group B2. High resistance observed for most antibiotics especially ampicilln, amoxcillin, lincomycin, cephalexin while resistance to amikacin and gentamicin was less common. Antibiotic resistance mainly appeared in integron positive isolates. In conclusion, high prevalence of antibiotic resistance especially among integron class 2 positive isolates that indicated role of gut flora as reservoir and source of antibiotic resistance.

Importance and implications of antibiotic resistance development in livestock and wildlife farming in South Africa: A Review

Antibiotic resistance (ABR) is regarded as one of today’s major global health challenges. The development of ABR in nature is a complex phenomenon with many influencing factors, of which the farming industry is labelled a significant contributor. The transfer of ABR to humans, which usually occurs via the food chain, is of concern for human health. A food source that is increasing in popularity is game meat, which is farmed widely in South Africa. The natural environment, including wildlife, is not isolated from the rest of the farm, and thus could be a source of ABR or possibly a transfer vector. It is therefore important to assess the ABR situation in wildlife species and the factors that influence its emergence and transfer. Elements that play a part in the development of ABR in game species include certain harvesting and slaughtering and other farming practices and closer contact with humans and other farm animals. Additionally, natural transfer vectors include wind, water, manure, crops and animals. Worryingly, there is lack of knowledge of this situation owing to inadequate monitoring, documentation and control of antibiotics in the farming industry. The objective of this review was to gain better understanding of this situation, which would aid in the development of surveillance systems and methods to prevent or hinder the development of ABR in wildlife species. Keywords: Antimicrobial resistance, food-borne pathogens, game meat, surveillance systems, zoonoses

Prevalence of antibiotic resistance genes in bacterial communities associated with Cladophora glomerata mats along the nearshore of Lake Ontario.

The alga Cladophora glomerata can erupt in nuisance blooms throughout the lower Great Lakes. Since bacterial abundance increases with the emergence and decay of Cladophora, we investigated the prevalence of antibiotic resistance (ABR) in Cladophora-associated bacterial communities up-gradient and down-gradient from a large sewage treatment plant (STP) on Lake Ontario. Although STPs are well-known sources of ABR, we also expected detectable ABR from up-gradient wetland communities, since they receive surface run-off from urban and agricultural sources. Statistically significant differences in aquatic bacterial abundance and ABR were found between down-gradient beach samples and up-gradient coastal wetland samples (ANOVA, Holm-Sidak test, p < 0.05). Decaying and free-floating Cladophora sampled near the STP had the highest bacterial densities overall, including on ampicillin- and vancomycin-treated plates. However, quantitative polymerase chain reaction analysis of the ABR genes ampC, tetA, tetB, and vanA from environmental communities showed a different pattern. Some of the highest ABR gene levels occurred at the 2 coastal wetland sites (vanA). Overall, bacterial ABR profiles from environmental samples were distinguishable between living and decaying Cladophora, inferring that Cladophora may control bacterial ABR depending on its life-cycle stage. Our results also show how spatially and temporally dynamic ABR is in nearshore aquatic bacteria, which warrants further research.

Antimicrobial Resistance in the Environment.

This review summarizes important publications from 2015 pertaining to the occurrence of antimicrobial resistance (AMR) in the environment. Emphasis is placed on sources of antibiotic resistance in the aquatic environment including wastewater treatment plants, hospitals, and agriculture, treatment and mitigation techniques, and surveillance and analysis methodologies for characterizing abundance data. As such, this review is organized into the following sections: i) occurrence of AMR in the environment, including surface waters, aquaculture, and wastewater ii) treatment technologies, and iii) technologies for rapid surveillance of AMR, iv) transmission between matrices, v) databases and analysis methods, and vi) gaps in AMR understanding.

Editorial: Special section of FEMS Microbiology Ecology on the environmental dimension of antibiotic resistance

The emergence of multi-drug-resistant human pathogens increasingly threatens the successful treatment of bacterial infections, and is now widely regarded as a global public health crisis. Antimicrobial resistance is a global problem, and managing resistance will require global action. As a start, many nations are now developing action plans to mitigate the development of antibiotic resistance. These action plans generally have three pillars, innovation, surveillance and stewardship; and are founded on the One Health concept. Namely, that humans and animals (companion and food animal producing) are inextricably linked to each other through the environment. Thus, research on the environmental dimension of antibiotic resistance has become a priority, within the broader context of maintaining the efficacy of antibiotics of crucial importance to human and animal medicine. This FEMS Microbiology Ecology thematic topic concerns recent progress made in our understanding of the environmental dimension of antibiotic resistance, here coined with the acronym EDAR. Most of the manuscripts were contributed by participants of the Third International Symposium on the Environmental Dimension of Antibiotic Resistance, EDAR3, held in Wernigerode, Germany in May 2015. The EDAR3 meeting follows EDAR2 held in Xiamen China in December 2013, and the original EDAR meeting held in Montebello Canada in March 2012. The consensus statement formulated by the participants of EDAR3 was ‘there are linkages between environmental sources of antibiotic resistance and resistance in clinical pathogens, and human activity can increase, expand and mobilize environmental genes responsible for resistance’. For more detail on the status of progress in the field there are several recent reviews that will be of interest (Finley et al . 2013; Durso and Cook 2014; Jechalke et al . 2014; Berendonk et al . 2015; Huijbers et al . 2015; Nesme and Simonet 2015; Williams-Nguyen et al. 2016). Here, we briefly … [↵][1]* Corresponding author: E-mail: kornelia.smalla{at}julius-kuehn.de [1]: #xref-corresp-1-1