The association between antimicrobials and the antimicrobial-resistant phenotypes and resistance genes of Escherichia coli isolated from hospital wastewaters and adjacent surface waters in Sri Lanka

Molecular Basis of Yeasts Antimicrobial Activity-Developing Innovative Strategies for Biomedicine and Biocontrol

In the context of the growing concern regarding the appearance and spread of emerging pathogens with high resistance to chemically synthetized biocides, the development of new agents for crops and human protection has become an emergency. In this context, the yeasts present a huge potential as eco-friendly agents due to their widespread nature in various habitats and to their wide range of antagonistic mechanisms. The present review focuses on some of the major yeast antimicrobial mechanisms, their molecular basis and practical applications in biocontrol and biomedicine. The synthesis of killer toxins, encoded by dsRNA virus-like particles, dsDNA plasmids or chromosomal genes, is encountered in a wide range of yeast species from nature and industry and can affect the development of phytopathogenic fungi and other yeast strains, as well as human pathogenic bacteria. The group of the "red yeasts" is gaining more interest over the last years, not only as natural producers of carotenoids and rhodotorulic acid with active role in cell protection against the oxidative stress, but also due to their ability to inhibit the growth of pathogenic yeasts, fungi and bacteria using these compounds and the mechanism of competition for nutritive substrate. Finally, the biosurfactants produced by yeasts characterized by high stability, specificity and biodegrability have proven abilities to inhibit phytopathogenic fungi growth and mycelia formation and to act as efficient antibacterial and antibiofilm formation agents for biomedicine. In conclusion, the antimicrobial activity of yeasts represents a direction of research with numerous possibilities of bioeconomic valorization as innovative strategies to combat pathogenic microorganisms.

Prevalence of diverse antimicrobial resistance genes and bacteria in sewage treatment plant-derived sludge environment

Antimicrobial resistance (AMR) contamination in the environment is one of the most significant worldwide threats of the 21st century. Since sludge is heavily exposed to diverse contaminants, including pharmaceuticals, the inhabitant bacterial population is expected to exhibit resistance to antimicrobial agents. In this study, sewage treatment plant (STP) sludge samples were analyzed to assess the antibiotic-resistant bacterial population, abundance of AMR genes (ermF, qnrS, Sul1, blaGES, blaCTX-M, and blaNDM), and mobile genetic elements (intl1 and IS26). Out of 16, six bacterial isolates exhibited resistance to 13 antibiotics with a high multiple antibiotic resistance index (MARI) (0.93) and high metal tolerance. Quantitative polymerase chain reaction showed the abundance of target genes ranging from 6.6 × 103 to 6.5 × 108 copies g-1 sludge. The overall outcome reveals that STP sludge comprised varied multidrug-resistant bacterial populations. It will give insights into the functions of heavy metals and biofilm development in the selection and spread of AMR genes and the associated bacteria. Therefore, the application of sludge needs proper screening for AMR and metal contamination prior to its countless applications. This study will contribute immensely to the risk analysis of STP effluents on environmental health, including control of AMR transmission.

Antibiotic resistance through the lens of One Health: A study from an urban and a rural area in Sri Lanka

This study aimed to investigate and compare the proportion of AMR Escherichia coli (E. coli) between urban (Dompe in the Western province) and rural (Dambana in the Sabaragamuwa province) areas in Sri Lanka. The overall hypothesis of the study is that there is a difference in the proportion of AMR E. coli between the urban and the rural areas. Faecal samples were collected from healthy humans (n = 109), dairy animals (n = 103), poultry (n = 35), wild mammals (n = 81), wild birds (n = 76), soil (n = 80) and water (n = 80) from both areas. A total of 908 E. coli isolates were tested for susceptibility to 12 antimicrobials. Overall, E. coli isolated from urban area was significantly more likely to be resistant than those isolated from rural area. The human domain of the area had a significantly higher prevalence of AMR E. coli, but it was not significantly different in urban (98%) and rural (97%) areas. AMR E. coli isolated from dairy animals, wild animals and water was significantly higher in the urban area compared with the rural area. There was no significant difference in the proportion of multidrug resistance (MDR) E. coli isolated from humans, wild animals and water between the two study sites. Resistant isolates found from water and wild animals suggest contamination of the environment. A multi-sectorial One Health approach is urgently needed to control the spread of AMR and prevent the occurrences of AMR in Sri Lanka.

Benzoxazine-grafted-chitosan biopolymer films with inherent disulfide linkage: Antimicrobial properties

Synthesis and fabrication of naturally sourced biopolymers, especially chitosan, grafted with renewable small molecules have recently attracted attention as efficient antimicrobial agents and are highly desired for sustainable material development. Advantageous inherent functionalities in biobased benzoxazine extend the possibility of crosslinking with chitosan which holds immense potential. Herein, a low-temperature, greener facile methodology is adopted for the covalent confinement of benzoxazine monomers bearing aldehyde and disulfide linkages within chitosan to form benzoxazine-grafted-chitosan copolymer films. The association of benzoxazine as Schiff base, hydrogen bonding, and ring-opened structures enabled the exfoliation of chitosan galleries, and such host-guest mediated interactions demonstrated outstanding properties like hydrophobicity, good thermal, and solution stability due to the synergistic effects. Furthermore, the structures empowered excellent bactericidal properties against both E. coli and S. aureus as investigated by GSH loss, live/dead fluorescence microscopy, and morphological alteration on the cell surface by SEM. The work provides the benefits of disulfide-linked benzoxazines on chitosan, offering a promising avenue for general and eco-friendly usage in wound-healing and packaging material.

Antimicrobial Resistance Development Pathways in Surface Waters and Public Health Implications

Human health is threatened by antibiotic-resistant bacteria and their related infections, which cause thousands of human deaths every year worldwide. Surface waters are vulnerable to human activities and natural processes that facilitate the emergence and spread of antibiotic-resistant bacteria in the environment. This study evaluated the pathways and drivers of antimicrobial resistance (AR) in surface waters. We analyzed antibiotic resistance healthcare-associated infection (HAI) data reported to the CDC's National Healthcare Safety Network to determine the number of antimicrobial-resistant pathogens and their isolates detected in healthcare facilities. Ten pathogens and their isolates associated with HAIs tested resistant to the selected antibiotics, indicating the role of healthcare facilities in antimicrobial resistance in the environment. The analyzed data and literature research revealed that healthcare facilities, wastewater, agricultural settings, food, and wildlife populations serve as the major vehicles for AR in surface waters. Antibiotic residues, heavy metals, natural processes, and climate change were identified as the drivers of antimicrobial resistance in the aquatic environment. Food and animal handlers have a higher risk of exposure to resistant pathogens through ingestion and direct contact compared with the general population. The AR threat to public health may grow as pathogens in aquatic systems adjust to antibiotic residues, contaminants, and climate change effects. The unnecessary use of antibiotics increases the risk of AR, and the public should be encouraged to practice antibiotic stewardship to decrease the risk.

Green phytoextracts as natural photosensitizers in LED-based photodynamic disinfection of multidrug-resistant bacteria in wastewater effluent

The photodynamic treatment (PDT) process is a promising technology to control emerging pollutants and antimicrobial resistance problems in the water environment. The reactive oxygen species (ROS) produced when natural and nontoxic photosensitizers (PS) are exposed to light are the key functional components of the PDT process that can effectively achieve microbial inactivation with minimal negative impact. This study examined the application of green phytoextracts from two plants, Chamaecyparis obtusa and Moringa oleifera, as natural photosensitizers for the white light-emitting diode (LED) based photodynamic disinfection of multidrug-resistant (MDR) and total coliforms (TC) from secondary effluent in full-scale municipal wastewater treatment plants. Gas chromatography-mass spectrometry and Fourier transform infrared spectroscopy showed that the phytoextracts contained 57 compounds, particularly aromatic and phenolic hydroxyl compounds. The phytoextracts showed an excellent activity as a PS compared to the intrinsic antibacterial effect. Under a light intensity of 17 mW/cm², the complete inactivation (6.55 Log CFU/mL) was observed at an irradiation time of 100 min for Escherichia coli ART-2 and 80 min for Staphylococcus aureus, meaning that E. coli was resistant. The light intensity was an important factor influencing photodynamic disinfection. For the complete disinfection of TC satisfying the water reclamation regulation, the irradiation time requirement was 20 min under a light intensity of 80 mW/cm². During the photodynamic reaction, a significant amount of ROS was generated from the phytoextracts as the light irradiation time was increased. The major ROS was singlet oxygen (¹O₂, Type II) during the initial 40 min of reaction time and hydroxyl radical (•OH, Type I) after 40 min until complete inactivation.

Insights into the spatiotemporal occurrence and mixture risk assessment of household and personal care products in the waters from rivers to Laizhou Bay, southern Bohai Sea

Household and personal care products (HPCPs) are a kind of contaminants closely related to daily life, capturing worldwide concern. To our knowledge, this is the first attempt focusing on the spatiotemporal occurrence and mixture risk of HPCPs in the waters from rivers to Laizhou Bay. Nine HPCPs were quantitated in 216 water samples gathered from Laizhou Bay and its adjacent rivers in 2018, 2019, and 2021 to reveal the spatiotemporal occurrence and mixture ecological risks in Laizhou Bay. Eight HPCPs were detected with detection frequencies ranging from 74% to 100%. The total concentrations were in the ranges 105-721 ng L^-1 in river water and 51.3-332 ng L^-1 in seawater. The HPCPs were dominated by p-hydroxybenzoic and triclosan, which together contributed over 75% of the total HPCPs. The average level of the total HPCP concentration in the summer of 2018 (96.1 ng L^-1) was slightly exceed that in the spring of 2019 (91.6 ng L^-1), which is associated with the higher usage of HPCPs and enhanced tourism during summer. However, the highest total concentrations were found in spring of 2021 (124 ng L^-1 in average), which was attribute to a higher level of methylparaben, a predominant paraben used as preservatives in commercial pharmaceuticals of China. Influenced by riverine inputs and ocean currents, higher HPCP concentrations in Laizhou Bay were found nearby the estuary of Yellow River and the southern part of the bay. Triclosan should be given constant concern considering its medium to high risks (RQ > 0.1) in nearly 80% of the water samples. The cumulative risk assessment in two approaches revealed that HPCP mixtures generally elicit medium or high risk to three main aquatic taxa. Considering the worldwide outbreak of COVID-19, the levels and risks of multiple HPCPs in natural waters requires constant attention in future studies.

Occurrence of Pharmaceutically Active Compounds and Potential Ecological Risks in Wastewater from Hospitals and Receiving Waters in Sri Lanka

The presence of pharmaceutically active compounds (PACs) in the environment and their associated hazards is a major global health concern; however, data on these compounds are scarce in developing nations. In the present study, the existence of 39 non-antimicrobial PACs and six of their metabolites in wastewater from hospitals and adjacent surface waters in Sri Lanka was investigated from 2016 to 2018. The highest amounts of the measured chemicals, including the highest concentrations of atorvastatin (14,620 ng/L) and two metabolites, mefenamic acid (12,120 ng/L) and o-desmethyl tramadol (8700 ng/L), were detected in wastewater from the largest facility. Mefenamic acid, gemfibrozil, losartan, cetirizine, carbamazepine, and phenytoin were detected in all the samples. The removal rates in wastewater treatment were 100% for zolpidem, norsertaline, quetiapine, chlorpromazine, and alprazolam. There was substantial variation in removal rates of PACs among facilities, and the overall data suggest that treatment processes in facilities were ineffective and that some PAC concentrations in the effluents were increased. The estimated risk quotients revealed that 14 PACs detected in water samples could pose low to high ecological risk to various aquatic organisms. Compounds such as ibuprofen, tramadol, and chlorpromazine detected in untreated and treated wastewater at these facilities pose a high risk to several aquatic organisms. Our study provides novel monitoring data for non-antimicrobial PAC abundance and the associated potential ecological risk related to hospitals and urban surface waters in Sri Lanka and further offers valuable information on pre-COVID-19 era PAC distribution in the country. Environ Toxicol Chem 2022;41:298-311. © 2021 SETAC.

Fate of land-based antibiotic resistance genes in marginal-sea sediment: Territorial differentiation and corresponding drivers

No large-scale investigations on fate of land-based antibiotic resistance genes (ARGs) in marginal sea have been reported. The Yellow Sea which is an important marginal sea was selected to investigate the fate, territorial differentiation, and drivers of target ARGs in marginal-sea sediments. ARGs might spread from land to sea with the average absolute abundance of total ARGs in marine/coastal sediments reaching 1.23 × 10⁴/9.79 × 10⁴ copies/g. The Yellow Sea Cold Water Mass was firstly observed to possibly have potential inhibition effect on occurrence of ARGs in marine sediments. Marine sediments showed significant difference from coastal sediments by considering ARGs, microbial community, and sediment features. Network analysis showed that interaction between ARGs and microbial community in coastal sediments was more frequent than that in marine sediment. The anthropogenic factors posed high positive effect on ARGs in marine/coastal sediments with contribution coefficient of 0.524/1.094 while bacterial community mainly posed positive effect on ARGs in marine sediments with contribution coefficient of 0.475, illustrating that spread and proliferation of land-based ARGs in marine sediments might be mainly affected by anthropogenic and microbial factors. These findings provided new information on fate and drivers of ARGs in marginal sea.

Prevalence and Antimicrobial Resistance Profiles of Foodborne Pathogens Isolated from Dairy Cattle and Poultry Manure Amended Farms in Northeastern Ohio, the United States

Foodborne pathogens significantly impact public health globally. Excessive antimicrobial use plays a significant role in the development of the public health crisis of antibiotic resistance. Here, we determined the prevalence and antimicrobial resistance profiles of E. coli O157, Salmonella, L. monocytogenes, and Campylobacter isolated between 2016 and 2020 from small scale agricultural settings that were amended with dairy cattle or poultry manure in Northeastern Ohio. The total prevalence of the foodborne pathogens was 19.3%: Campylobacter 8%, Listeria monocytogenes 7.9%, Escherichia coli O157 1.8%, and Salmonella 1.5%. The prevalence was significantly higher in dairy cattle (87.7%) compared to poultry (12.2%) manure amended farms. Furthermore, the prevalence was higher in manure samples (84%) compared to soil samples (15.9%; p < 0.05). Multiple drug resistance was observed in 73%, 77%, 100%, and 57.3% of E. coli O157, Salmonella, L. monocytogenes, and Campylobacter isolates recovered, respectively. The most frequently observed resistance genes were mphA, aadA, and aphA1 in E. coli O157; blaTEM, tet(B), and strA in Salmonella; penA, ampC, lde, ermB, tet(O), and aadB in L. monocytogenes and blaOXA-61, tet(O), and aadE in Campylobacter. Our results highlight the critical need to address the dissemination of foodborne pathogens and antibiotic resistance in agricultural settings.

Isolation and molecular identification of extended spectrum beta-lactamase producing bacteria from urinary tract infection

BACKGROUND

Recent years, the treatment of multi-drug resistant bacteria and their effect are very difficult due to the virulence factors modification. Based on the world wide thread, we have tried to identify the ESBLs producing bacteria from urinary tract infection patients. In result, the highly antibiotic resistant effect of Pseudomonas aeruginosa and Klebsiella pneumoniae were identified.

METHODS

Initially, Hexa disc diffusion method was performed to detect the multi-drug resistant bacteria using respective antibiotics of HX066, HX033 and HX077, HX012 discs. Consecutively, the ESBL producing ability of confirmed multi drug resistant bacteria was performed to detect their ESBL producing ability using specific extended spectrum beta lactamase (ESBLs) detection discs of Hexa G-minus 24. Furthermore, the ESBL producing ability of the bacteria was confirmed by ESBLs detection Ezy MIC™ E-test stripe method.

RESULTS AND CONCLUSIONS

In result, 10, 5 and 4 mm and 10, 14 and 8 mm zone of inhibition against imipenem (IPM), Ticarcillin/Clavulanic acid (TCC), Cefoperazone (CPZ) and Ampicillin (AMP), Norfloxacin (NX), Nalidixic acid (NA) antibiotics for P. aeruginosa and 16, 22 and 10, 18 mm zone of inhibition against ceftazidime (CAZ), methicillin (MET), ampicillin amoxyclav (AMC), co-trimoxazole (COT) of the HX077 HX012 for K. pneumoniae were observed. Based on the Clinical & Laboratory Standards Institute (CLSI) guidelines, both the bacteria were more resistant to tested antibiotics and it could be developed more resistant against all the tested antibiotics. In addition, the phenotypic detection of ESBL production effect was also performed against both the selected uropathogens, and the results were shown ≥22 mm, ≥27 zone of inhibition against all the tested antibiotics. Further, the genetic identification of multi plux PCR result was shown TEM, SHV and CTX-m genes were present in both the selected uropathogens. Finally, our results were correlated each other and concluded that the selected uropathogens were multi drug resistant effect and also ESBLs producer.

A 'time bomb' in the human intestine-the multiple emergence and spread of antibiotic-resistant bacteria

Antibiotics have a strong killing effect on bacteria and are the first choice for the prevention and treatment of bacterial infectious diseases. Therefore, they have been widely used in the medical field, animal husbandry and planting industry. However, with the massive use of antibiotics, more and more antibiotic-resistant bacteria (ARB) have emerged. Because human intestines are rich in nutrients, have suitable temperature, and are high in bacterial abundance, they can easily become a hotbed for the spread of ARB and antibiotic-resistant genes (ARGs). When opportunistic pathogenic bacteria in the intestine acquire ARGs, the infectious diseases caused by such opportunistic pathogens will become more difficult to treat, or even impossible to cure. Therefore, ARB in the human intestine are like a 'time bomb'. In this review, we discuss the sources of intestinal ARB and the transmission routes of ARGs in the human intestine from the perspective of One Health. Further, we describe various methods to prevent the emergence of ARB and inhibit the spread of ARGs in the human intestine. Finally, we may be able to overcome ARB in the human intestine using an interdisciplinary 'One Health' approach.