Distribution Of Antibiotic-resistant Bacteria Research Articles

Spatial Distribution and Seasonal Variation of Antibiotic-Resistant Bacteria in an Urban River in Northeast China

As the largest freshwater river flowing through Harbin, the Songhua River is a standby water source. It is very important to know the species and distribution of antibiotic-resistant bacteria (ARB) in the river. In this study, five antibiotics were selected to screen and identify ARB in spring and autumn. The results showed that the concentration of cefotaxime-resistant bacteria was the highest, and the maximum concentration at S6 in spring was up to 1.40 × 104 CFU/mL. In spring and autumn, bacteria resistant to three antibiotics were screened at S1 of the Songhua River, and bacteria resistant to five antibiotics were screened at S6. No multiple antibiotic-resistant bacteria (MARB) were screened in the other four sites in autumn, while MARB were screened in the other three samples except S2 in spring. In all sample areas in spring and autumn, the probability of screening MARB at S1 and S6 was the highest, reaching 100%. The identification results of 16S rDNA polymerase chain reaction (PCR) products of ARB showed that a total of 51 ARB strains from 15 bacterial genera were screened in the Songhua River, of which 20 ARB strains were from Pseudomonas. Among the 15 bacterial genera, bacteria from 8 bacterial genera have pathogenicity. The results of this study revealed the concentration, spatial distribution, and seasonal variation of culturable ARB in the Songhua River, providing data support for the remediation of antibiotic resistance gene (ARG) pollution in the river.

Distribution of antibiotic resistant bacteria and genes in sewage and surrounding environment of Tórshavn, Faroe Islands

Several studies have investigated the effects of swimming in sewage-polluted recreational beach water, highlighting the associated health hazards. To mitigate potential pathogen transmission, it is imperative that the polluted water is released away from recreational waters and foreshores, where children tend to play. At present, domestic sewage in the Faroe Islands solely undergoes primary wastewater treatment within primary settling tanks before being discharged into the ocean. Effluents are a major anthropogenic source of antibiotic resistance genes and antibiotic resistant bacteria, which are released into the environment. The aim of this study was to investigate antibiotic resistant Gram-negative bacteria and antibiotic resistance genes in influents and effluents of wastewater subjected solely to primary treatment, along with their release into the environment during both summer and winter. Water samples were collected from influents and effluents as well as with increasing distance away from the wastewater outlet and from nearby tidepools. Samples were cultured on MacConkey agar with four different antibiotics for detection of antibiotic-resistant bacteria and antibiotic resistance genes were quantified by droplet digital PCR. All multi-drug resistant bacteria were identified using the API 20E kit. We observed an overall decrease of the abundance of Gram-negative bacteria from the effluents compared to influents, however, we observed the opposite trend in the antibiotic resistance genes. Antibiotic resistant bacteria and antibiotic resistance genes in addition to multi-drug resistant bacteria were found in the surrounding oceanic and several terrestrial tidepool samples. Of the multi-drug resistant bacteria, we found, e.g., Escherichia coli, P. aeruginosa, and A. hydrophila species, which can be pathogenic, potentially causing an infection if encountering a host. These results indicate a relatively wide pollution range of the effluents from the septic tank and treated sewage released into the environment, posing a potential hazard for both humans and wildlife.

Occurrence and environmental risks of contaminants of emerging concern across the River Athi Basin, Kenya, in dry and wet seasons

Globally, the environmental occurrence of Contaminants of Emerging Concern (CECs) including pharmaceuticals (PhACs), personal care products (PCPs) and modern polar pesticides has raised ecological and human health awareness. However, as the developed world races against time to establish regulatory measures to mitigate their effects, developing nations including Kenya are lagging behind, partly due to unavailability of adequate data. In this work, a multi-residue analysis of 86 CECs was carried out on 198 surface water and 18 effluent samples collected at 24 sites across the River Athi basin area, Kenya, in both dry and rainy seasons. Overall, 57 CECs comprising 31 PhACs (0.4 ng L−1–142 μg L−1), 6 PCPs (0.7–570 ng L−1) and 20 pesticides (0.3 ng L−1–8.3 μg L−1) were detected. The maximum loads varied from 217 g day−1 (PCPs) to 46 kg day−1 (PhACs). Individually, carbamazepine, nevirapine, sulfamethoxazole and DEET were the most ubiquitous CECs, with detection frequencies (DF) higher than 80 %. The highest concentrations were observed at river sites that are heavily impacted by informal settlements, highlighting the critical role of slums in urban rivers pollution. At least 8 CECs including acetamiprid, alachlor, atrazine, diuron, nevirapine and paracetamol show potential risk to algae, Daphnia magna and fish, as exemplified by Risk Quotients (RQ) up to 174. Similarly, potential risk of antibiotic resistant bacteria development is evident (RQ up to 64), being driven by metronidazole, sulfamethoxazole and trimethoprim. Ultimately, further studies on the occurrence and distribution of antibiotic resistant bacteria within the basin and among the communities consuming untreated river water for drinking is merited.

Distribution of antibiotic resistant bacteria in different soil types following manure application

Distribution of antibiotic resistant bacteria in different soil types following manure application

Prevalence and distribution of antibiotic-resistant bacteria in the rhizosphere and rhizoplane of Suaeda salsa and Sporobolus alterniflorus grown in a pristine environment

Antibiotic-resistant bacteria (ARB) are believed to have originated from pristine soil environments. However, the prevalence of ARB in the root-associated niches of plants grown in these environments, as well as the distribution patterns of ARB in the rhizosphere and rhizoplane—two critical root-associated niches—remains elusive. In this study, we investigated the prevalence and distribution of ARB in the rhizosphere and rhizoplane of two main plant species, Suaeda salsa and Sporobolus alterniflorus, grown in a pristine environment in Yancheng, China, to address these questions. In total,181 bacterial strains were isolated from the root-associated niches of the two plant species. Strong niche differentiation of the bacterial community between the rhizosphere and rhizoplane was identified by both bacterial isolation- and high-throughput 16S ribosomal RNA gene (rDNA) sequencing-based analyses. In total, 69.06 % of the isolated bacterial strains were classified as ARB, with strains resistant to β-lactam class antibiotics and polymyxin being predominant. The relative abundance of ARB in the rhizoplane was higher than that in the rhizosphere for both plant species. Furthermore, variations were noted in the prevalence and distribution of ARB in the root-associated niches between the two species. Several pathogenic ARBs, such as Stenotrophomonas maltophilia, were identified among the isolated strains. A representative S. maltophilia strain was sequenced, and several important antibiotic resistance- and pathogenicity-associated genes were identified in its genome. These findings provide novel insights into the prevalence and distribution patterns of ARB in the rhizosphere and rhizoplane of plants grown in pristine environments.

Isolation and genotypic characterization of extended-spectrum beta-lactamase-producing Escherichia coli O157:H7 and Aeromonas hydrophila from selected freshwater sources in Southwest Nigeria

The proliferation of antibiotic-resistant bacteria and antimicrobial resistance is a pressing public health challenge because of their possible transfer to humans via contact with polluted water sources. In this study, three freshwater resources were assessed for important physicochemical characteristics as well as heterotrophic and coliform bacteria and as potential reservoirs for extended-spectrum beta-lactamase (ESBL) strains. The physicochemical characteristics ranged from 7.0 to 8.3; 25 to 30 °C, 0.4 to 93 mg/L, 0.53 to 8.80 mg/L and 53 to 240 mg/L for pH, temperature, dissolved oxygen (DO), biological oxygen demand (BOD5) and total dissolved solids, respectively. The physicochemical characteristics mostly align with guidelines except for the DO and BOD5 in some instances. Seventy-six (76) Aeromonas hydrophila and 65 Escherichia coli O157: H7 isolates were identified by preliminary biochemical analysis and PCR from the three sites. Among these, A. hydrophila displayed higher frequencies of antimicrobial resistance, with all 76 (100%) isolates completely resistant to cefuroxime and cefotaxime and with MARI ≥ 0.61. The test isolates showed more than 80% resistance against five of the ten test antimicrobials, with resistance against cefixime, a cephalosporin antibiotic being the highest at 95% (134/141). The frequency of the detection of the resistance genes in the A. hydrophila isolates generally ranged between 0% (blaSHV) and 26.3% (blaCTX-M), while the frequency of detection among the E. coli O157:H7 isolates ranged between 4.6% (blaCTX-M) and 58.4% (blaTEM). Our findings indicate that the distribution of antibiotic-resistant bacteria with diverse ESBL-producing capabilities and virulence genes in freshwater sources potentially threatens public health and the environment.

Application of nematicide avermectin enriched antibiotic-resistant bacteria and antibiotic resistance genes in farmland soil

The extensive use of antibiotics in medicine and agriculture has resulted in the accumulation of antibiotic-resistant microorganisms and antibiotic resistance genes (ARGs) in environments, which threaten human health and contaminate environment. Nematicide avermectin is widely applied to control root-knot nematodes. The effect of five-years application of avermectin on rhizosphere microbiome and resistome of sick tobacco plants in farmland were investigated in present study. The environmental risks of avermectin was assessed adequately. Metagenomic method was used to analyze antibiotic-resistant bacteria and antibiotic resistance genes in the avermectin-treated soil. The abundance and distribution of antibiotic-resistant bacteria and their antibiotic resistance genes were affected by avermectin application. The antibiotic resistant Proteobacteria occupied the highest percentage (36%) in rhizosphere soil and carried 530 ARGs. Opportunistic human pathogens carrying antibiotic resistance genes were enriched in the avermectin-treated soil. Avermectin application increased the counts of many types of antibiotic resistance genes. The relative abundances of genes adeF, BahA, fusH, ileS, and tlrB in the avermectin-treated soil were significantly greater than in the untreated control soil. Different resistance mechanisms were revealed in the avermectin-treated soil. The efflux of antibiotic (670 ARGs), inactivation of antibiotic (475 ARGs), and alteration of antibiotic target (267 ARGs) were the main resistance mechanisms. Rigid control the avermectin dose and use frequency and other pesticides can decrease soil antibiotic resistance genes and protect agricultural products’ safety and public health. Overall, application of nematicide avermectin enriched antibiotic-resistant bacteria and antibiotic resistance genes in farmland soil, which should be on the alert for environment protection.

Distribution analysis of tetracycline resistance genes in Escherichia coli isolated from floor surface and effluent of pig slaughterhouses in Banten Province, Indonesia.

Slaughterhouses and their effluents could serve as a "hotspot" for the occurrence and distribution of antibiotic-resistant bacteria in the environment. This study aimed to understand the distribution of tetracycline resistance genes in Escherichia coli isolated from the floor surface and effluent samples of pig slaughterhouses in Banten Province, Indonesia. Ten samples, each from floor surface swabs and effluents, were collected from 10 pig slaughterhouses in Banten Province. Escherichia coli strains were isolated and identified by referring to the protocol of the Global Tricycle Surveillance extended-spectrum beta-lactamase E. coli from the WHO (2021). Quantitative real-time polymerase chain reaction (qPCR) was used to detect the tet genes. The tetA, tetB, tetC, tetM, tetO, and tetX genes were distributed in the isolates from the floor surface samples, and the tetA, tetC, tetE, tetM, tetO, and tetX genes were distributed in the isolates from the effluent samples. The tetO gene (60%) was the most dominant gene in the isolates from floor surface samples, while the tetA gene was the dominant one in the isolates from the effluent samples (50%). The tetA + tetO gene combination was the dominant pattern (15%) in the E. coli isolates. The high prevalence and diversity of the tet genes in floor surface and effluent samples from pig slaughterhouses in Banten Province indicated that the transmission of the tet genes had occurred from pigs to the environment; thus, this situation should be considered a serious threat to public health.

Antibiogram Analysis of Escherichia coli Isolates Recovered from Dog Faeces

Antimicrobial resistance is a global problem affecting animals and humans. Improper use of antibiotics by humans, inefficient prevention and control of infections, poor hygiene and sanitation, are causes for the emergence and distribution of antibiotic resistant bacteria. The role of pets is quite significant as disseminators of antimicrobial-resistant bacteria. This study was planned to analyze the antibiotic susceptibility profile of Escherichia coli isolated from dog faeces. The dog faecal samples (n=5) collected from Veterinary Clinical Complex, College of Veterinary and Animal Science, Navania were subjected to bacteriological examination for the isolation and identification of Escherichia coli. The isolates were confirmed by PCR to detect the species specific uspA gene. Antimicrobial susceptibility testing was done to determine the antibiotic susceptibility pattern of the isolates. In the present study, it was revealed that out of 5 dog faecal samples analyzed, E coli was isolated from 4 samples. The PCR analysis revealed a specific amplification of 884 bp product of the uspA gene among the isolates. Further on analyzing the antibiogram, it was found that chloramphenicol, oxytetracycline, azithromycin, ampicillin, co-trimoxazole and ceftriaxone were effective against E. coli. While, the isolates were resistant to amoxicillin and trimethoprim. Therefore, it was concluded that the screening of cultures by antimicrobial susceptibility testing will not only help in deciding the right antibiotic for treatment but also identify the shifting trends of antimicrobial resistance.

Occurrence and distribution of antibiotic resistant bacteria and genes in the Fuhe urban river and its driving mechanism

Antibiotic resistance genes (ARGs) in urban rivers can affect human health via the food chain and human pathogenic bacteria diffusion. Sediment can be a sink for ARGs, causing second sources of ARG contamination through diffusion. Therefore, we evaluated the effects of total petroleum hydrocarbons (TPHs) and phytoplankton on the distribution of the ARGs in the sediment and water of Fuhe river in Baoding city, China. The ARGs and human pathogenic bacteria in urban river were analyzed, and the phytoplankton and bacterial abundance, TPH, and physicochemical parameters ranked using the partial least squares path modelling (PLS-PM) and aggregated boosted tree (ABT) analysis. The main ARGs in Fuhe river sediment were sulfonamide and tetracycline resistance genes, with sul2 exhibiting the highest level. The main human pathogenic bacteria in the pathogens pool were Clostridium, Bacillus and Burkholderiaceae, with Clostridium demonstrating a positive correlation with SulAfolP01. The PLS-PM analysis confirmed that, among the multiple drivers, water physicochemical factors, TPH, phytoplankton, and heavy metals positively and directly affected the ARG profiles in sediment while sediment heavy metals and bacterial communities did the similar effect. These factors (nutrient factors, heavy metals, and TPH) in water and sediment posed the opposite total effect on ARGs in the sediment, suggesting medium factors should have a conclusive effect on the distribution of ARGs in the sediment. The ABT analysis showed that dissolved oxygen (DO), total nitrogen (TN) and Chlorophyta were the most important factors affecting the ARGs distribution in the water, while TN affected the distribution of the genes in the sediment.

Applicability of bio-synthesized nanoparticles in fungal secondary metabolites products and plant extracts for eliminating antibiotic-resistant bacteria risks in non-clinical environments

The abundance of antibiotic-resistant bacteria in the prawn pond effluents can substantially impact the natural environment. The settlement ponds, which are the most common treatment method for farms wastewater, might effectively reduce the suspended solids and organic matter. However, the method is insufficient for bacterial inactivation. The current paper seeks to highlight the environmental issue associated with the distribution of antibiotic resistant bacteria (ARB) from prawn farm wastewater and their impact on the microbial complex community in the surface water which receiving these wastes. The inactivation of antibiotic-resistant bacteria in prawn wastewater is strongly recommended because the presence of antibiotic-resistant bacteria in the environment causes water pollution and public health issues. The nanoparticles are more efficient for bacterial inactivation. They are widely accepted due to their high chemical and mechanical stability, broad spectrum of radiation absorption, high catalytic activity, and high antimicrobial activity. Many studies have examined the use of fungi or plants extract to synthesis zinc oxide nanoparticles (ZnO NPs). It is evident from recent papers in the literature that green synthesized ZnO NPs from microbes and plant extracts are non-toxic and effective. ZnO NPs inactivate the bacterial cells as a function for releasing reactive oxygen species (ROS) and zinc ions. The inactivation of antibiotic-resistant bacteria tends to be more than 90% which exhibit strong antimicrobial behavior against bacterial species.

Distribution of antibiotic-resistant bacteria in aerobic composting of swine manure with different antibiotics

BackgroundLivestock manure is an important reservoir of antibiotic-resistant bacteria (ARB) and antibiotic-resistance genes (ARGs). The bacterial community structure and diversity are usually studied using high-throughput sequencing that cannot provide direct evidence for ARB changes. Thus, little is known about the distribution of ARB, especially in the presence of different antibiotics in composting process. In this study, the fate of ARB was investigated in aerobic composting of swine manure, using chlortetracycline, sulfamethoxazole, lincomycin, and ciprofloxacin as typical antibiotics. The abundance and species of ARB were analyzed systematically to evaluate their ecological risk at different stages of composting.ResultsThe absolute abundance of total ARB decreased, while the relative abundance increased on day 2. The relative abundance of lincomycin-resistant bacteria was higher than other ARBs during the whole composting process. The absolute abundance of four ARBs was 9.42 × 106–2.51 × 102 CFU/g (lincomycin- > chlortetracycline- > sulfamethoxazole- > ciprofloxacin- > multiple antibiotic-resistant bacteria), and they were not completely inactivated at the end of composting. Antibiotics led to a partial proliferation of ARBs including Corynebacterium, Sporosarcina, Solibacillus, and Acinetobacter. Especially, Corynebacterium, a pathogenic genus, was observed in chlortetracycline and lincomycin treatments.ConclusionAmong the antibiotics studied, lincomycin showed the highest ecological risk, due to it expanded the range of lincomycin-resistant bacteria at the phyla level (Firmicutes, Actinobacteria, and Proteobacteria). The principal co-ordinates analysis indicated that the bacterial community structure was primarily associated with the composting stages rather than antibiotic types. Possible potential hosts and the related to the decrease of ARGs abundance were indicated based on the network analysis. The decrease of culturable Proteobacteria and the increase of culturable Firmicutes (Solibacillus, Bacillus) partially explained the high degradation rate of various ARGs with the progress of composting in this study. These results provided important information for the control of antibiotic resistance in composting.

Distribution of Antibiotic-Resistant Bacteria in the Livestock Farm Environments

The surroundings of livestock farms, including dairy farms, are known to be a major source of development and transmission of antibiotic-resistant bacteria. To control antibioticresistant bacteria in the livestock breeding environment, farms have installed livestock wastewater treatment facilities to treat wastewater before discharging the final effluent in nearby rivers or streams. These facilities have been known to serve as hotspots for inter-bacterial antibiotic-resistance gene transfer and extensively antibiotic-resistant bacteria, owing to the accumulation of various antibiotic-resistant bacteria from the livestock breeding environment. This review discusses antibiotic usage in livestock farming, including dairy farms, livestock wastewater treatment plants as hotspots for antibiotic resistant bacteria, and nonenteric gram-negative bacteria from wastewater treatment plants, and previous findings in literature.

Antibiotic Resistance of Bacteria in Two Marine Mammal Species, Harbor Seals and Harbor Porpoises, Living in an Urban Marine Ecosystem, the Salish Sea, Washington State, USA

The pervasive use of antibiotics in human medicine, veterinary medicine, and agriculture can result in a significant increase in the spread and environmental persistence of antibiotic resistance in marine ecosystems. This study describes the presence and distribution of antibiotic-resistant bacteria in Salish Sea harbor seals (Phoca vitulina) and harbor porpoises (Phocoena phocoena) and evaluates species, age class, and geographic differences in resistance patterns. Isolates from 95 dead-stranded animals (74 seals/21 porpoises) were tested for resistance to a suite of 15 antibiotics. Of the 95 sampled, 85 (89%) (67 seals/18 porpoises) successfully yielded 144 isolates, with 37% resistant to at least one antibiotic and 26% multi-drug resistant (24% and 39% of seal and porpoise isolates, respectively). Overall, and by study region, porpoises were significantly more likely to harbor resistant organisms compared to seals. Significant differences between age classes were noted for the antibiotics amoxicillin, cephalexin, and cefovecin. Overall isolate resistance was significantly greater in porpoises than seals for several individual antibiotics. Multiple antibiotic resistance (MAR) indices greater than 0.2 were observed in 55% of multi-drug resistant isolates, suggesting seal and porpoise exposure to anthropogenic pollution. The relatively high and disparate prevalence of antibiotic resistance in these common, but ecologically dissimilar, marine mammals reflects a potentially large environmental pool of antibiotic resistant organisms in the Salish Sea or inherently different resistance gene patterns between the two species.

Isolation of Antibiotic Resistant Bacteria from Rivers in Kelantan, Malaysia

Antibiotic resistant bacteria have been a major concern due to the problems that they may pose in terms of public and environmental health. This present study aimed to investigate the presence of antibiotic resistance among bacterial strains isolated from rivers and to determine the impact of various human activities on the distribution of antibiotic resistant bacteria. Bacteria were isolated from river water samples of Lebir River (Point 1 and Point 2) and Kelantan River (Point 3 and Point 4). Antibiotic susceptibility test was conducted on the bacterial isolates against six types of antibiotics (ampicillin, gentamycin, tetracycline, chloramphenicol, rifampicin and ciprofloxacin) was performed, followed by characterization and identification of the isolates using a series of biochemical tests. The findings show the presence of antibiotic resistant bacteria in all four samples, indicating the relationship between the resistance of isolates and the human activities within the vicinity of the area. A total of 27 bacterial isolates were successfully isolated from the rivers and predicted as Actinomyces sp., Arachnia sp., Streptomyces sp., Streptococcus sp., Enterococcus sp., Bacillus sp., Clostridium sp., Neisseria sp., Veillonella sp., Bacteroides sp., Salmonella sp., Shigella sp., Proteus sp., Enterobacter sp., Klebsiella sp., Escherichia sp, Pseudomonas sp., Aeromonas sp., Vibrio sp. Staphylococcus sp., Micrococcus sp., Actinobacillus sp., and Flavobacterium sp. However, further analysis of the antibiotic resistant bacteria is recommended to further identify and understand them due to the potential risk that they may pose to human and environment.

Environmental Factors and Pollution Stresses Select Bacterial Populations in Association With Protists

Digestion-resistant bacteria (DRB) refer to the ecological bacterial group that can be ingested, but not digested by protistan grazers, thus forming a specific type of bacteria-protist association. To test the hypothesis that the environment affects the assembly of DRB in protists, a mixotrophic ciliate, Paramecium bursaria, and a heterotrophic ciliate, Euplotes vannus, were reared at different temperatures, light conditions, and concentration gradients of antibiotic oxytetracycline and heavy metals. Community profiling indicated that the composition of DRB in both species varied significantly across the manipulated conditions, except for in P. bursaria under light/dark treatments. Clone library analysis of bacterial 16S rRNA genes showed that DRB were diverse. Pseudomonas became more abundant during the warmer treatment of P. bursaria, whereas the dominance of Pseudoalteromonas weakened and Vibrio became more abundant in E. vannus at a higher temperature. During the treatment of diel light:dark cycles, Aestuariibacter and Alteromonas were selected for in E. vannus but not Pseudoalteromonas, which was highly represented in the all-light and alldark treatments. In contrast, P. bursaria consistently hosted Nevskia, Curvibacter, and Asticcacaulis under all light conditions. There were many bacterial species co-resistant to oxytetracycline and to protistan digestion, in which Sphingomonas, Alteromonas, Aestuariibacter, Puniceicoccaceae (Verrucomicrobia), Pseudomonas, and Sulfitobacter were frequently abundant. Flectobacillus and Aestuariibacter were major lead-resistant bacteria associated with the studied protists. Acinetobacter and Hydrogenophaga were abundant in the P. bursaria treated with a high dose of mercury. Aestuariibacter was found as a dominant group of DRB in E. vannus across all cadmium treatments. In summary, this study demonstrates for the first time that environmental stress selects for bacterial populations associated with protists and that there are diverse bacterial species that not only are resistant to pollution stresses but can also survive protistan predation. This work highlights that bacteria-protists associations need to be taken into account in understanding ecological and environmental issues, such as resilience of bacterial community and function, microbial co-occurrence, and quantity and distribution of antibiotic resistant bacteria and genes.

Spatial relationships between small-holder farms coupled with livestock management practices are correlated with the distribution of antibiotic resistant bacteria in northern Tanzania

We examined the spatial distribution of antibiotic-resistant coliform bacteria amongst livestock from three distinct cultural groups, where group-level differences in practices (e.g., antibiotic use) may influence the magnitude of antibiotic resistance, while livestock interactions (e.g., mixing herds, shared markets) between these locations may reduce heterogeneity in the distribution of antibiotic resistant bacteria. Data was collected as part of a larger study of antibiotic-resistance in northern Tanzania. Simple regression and generalized linear regression were used to assess livestock management and care practices in relation to the prevalence of multidrug-resistant (MDR) coliform bacteria. Simple and multivariable logistic regression were then used to identify how different management practices affected the odds of households being found within MDR “hotspots.” Households that had a higher median neighbourhood value within a 3000 m radius showed a significant positive correlation with livestock MDR prevalence (β = 4.33, 95% CI: 2.41–6.32). Households were more likely to be found within hotspots if they had taken measures to avoid disease (Adjusted Odds Ratio (AOR) 1.53, CI: 1.08—2.18), and if they reported traveling less than a day to reach the market (AOR 2.66, CI: 1.18—6.01). Hotspot membership was less likely when a greater number of livestock were kept at home (AOR 0.81, CI: 0.69–0.95), if livestock were vaccinated (AOR 0.32, CI: 0.21—0.51), or if distance to nearest village was greater (AOR 0.46, CI: 0.36–0.59). The probability of MDR increases when herds are mixed, consistent with evidence for passive transmission of resistant bacteria between animals. Reduced MDR with vaccination is consistent with many studies showing reduced antibiotic use with less disease burden. The neighbourhood effect has implications for design of intervention studies.

Anthropogenic influence shapes the distribution of antibiotic resistant bacteria (ARB) in the sediment of Sundarban estuary in India

The abundance and dissemination of antibiotic resistance genes as emerging environmental contaminants have become a significant and growing threat to human and environmental health. Traditionally, investigations of antibiotic resistance have been confined to a subset of clinically relevant antibiotic-resistant bacterial pathogens. During the last decade it became evident that the environmental microbiota possesses an enormous number and diversity of antibiotic resistance genes, some of which are very similar to the genes circulating in pathogenic microbiota. Recent studies demonstrate that aquatic ecosystems are potential reservoirs of antibiotic-resistant bacteria (ARBs) and antibiotic resistance genes (ARGs). Therefore, these aquatic ecosystems serve as potential sources for their transmission of ARGs to human pathogens. An assessment of such risks requires a better understanding of the level and variability of the natural resistance background and the extent of the anthropogenic impact. We have analyzed eight sediment samples from Sundarban mangrove ecosystem in India, collected at sampling stations with different histories of anthropogenic influences, and analyzed the relative abundance of the blaTEM gene using quantitative real-time PCR. The blaTEM gene abundance strongly correlated with the respective anthropogenic influences (polyaromatic hydrocarbon, heavy metals etc.) of the sampling stations. Besides, 18 multidrug-resistant (ampicillin, kanamycin, vancomycin, and tetracycline resistant) bacterial strains (ARBs) were isolated and characterized. Moreover, the effect of different antibiotics on the biofilm forming ability of the isolates was evaluated quantitatively under a variety of experimental regimes. This is the first report of preservation and possible dissemination of ARGs in the mangrove ecosystem.

Proliferation of Ciprofloxacin resistant bacteria in polluted sediments of Musi river, India

Improper disposal of domestic sewage and effluents from drug manufacturing units for several years has resulted in the accumulation of pollutants in Musi river sediments. There were no studies carried out before to quantify the antibiotic resistance in this river, despite the fact that its sediments are loaded with antibiotics. The present study investigated the relationship between the proliferation of ciprofloxacin resistant culture with the occurrence of fluoroquinolone and heavy metals in sediments of Musi River. The fluoroquinolones concentration in river sediments were observed in high concentration (13336.4 ng/g) and were found to be positively correlated with the occurrence of ciprofloxacin resistant bacteria (r = 0.386 to 0.675, p<0.05). The occurrence of heavy metals was also in positive correlation with the distribution of antibiotic resistant bacteria in the river (r = 0.454 to 0.881, p<0.05). This study indicated the spread of antibiotic resistance in polluted river sediments which might pose a serious threat to public health as the river water is used for irrigation, drinking, and recreational purposes; and needs an immediate risk assessment and mitigation strategies.

Proliferation of Ciprofloxacin Resistant Bacteria in Polluted Sediments of Musi River, India

ABSTRACTImproper disposal of domestic sewage and effluents from drug manufacturing units for several years has resulted in the accumulation of pollutants in Musi river sediments. There were no studies carried out before to quantify the antibiotic resistance in this river, despite the fact that its sediments are loaded with antibiotics. The present study investigated the relationship between the proliferation of ciprofloxacin resistant culture with the occurrence of fluoroquinolone and heavy metals in sediments of Musi River. The fluoroquinolones concentration in river sediments were observed in high concentration (13336.4 ng/g) and were found to be positively correlated with the occurrence of ciprofloxacin resistant bacteria (r = 0.386 to 0.675, p < 0.05). The occurrence of heavy metals was also in positive correlation with the distribution of antibiotic resistant bacteria in the river (r = 0.454 to 0.881, p < 0.05). This study indicated the spread of antibiotic resistance in polluted river sediments that might pose a serious threat to public health as the river water is used for irrigation, drinking, and recreational purposes; and needs an immediate risk assessment and mitigation strategies.