scholarly journals Removal of antibiotic resistance genes in secondary effluent by slow filtration-NF process

2021 ◽  
Author(s):  
Lihua Sun ◽  
Yao Ma ◽  
Yu Ding ◽  
Xiaoyu Mei ◽  
Yehui Liu ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Population Structure ◽  
Resistance Genes ◽  
Filtration Rate ◽  
Microbial Population ◽  
Antibiotic Resistance Genes ◽  
Secondary Effluent ◽  
Combined Process ◽  
Optimal Filtration ◽  
Slow Filtration

Abstract In this study, the combined process of slow filtration and low pressure nanofiltration (NF) has been used to deeply remove the antibiotic resistance genes (ARGs) in a secondary effluent, and the mechanism of ARGs removal has been subsequently explored. It is observed that the optimal filtration rate for the slow filtration without biofilm, slow filtration with the aerobic heterotrophic biofilm, slow filtration with the nitrification biofilm and slow filtration with the denitrification biofilm to remove tet A, tet W, sul I, sul II and DOC is 20 cm/h, and the slow filtration with the aerobic heterotrophic biofilm exhibits the highest removal amount. The slow filtration with biofilms removes a high extent of free ARGs. As compared with the direct NF of the secondary effluent and the slow filtration without biofilm-NF, the slow filtration with the aerobic heterotrophic biofilm-NF combined process exhibits the best ARGs removal effect. The microbial population structure and the high filtration rate in the aerobic heterotrophic biofilmand promote the removal of ARGs. Strengthening the removal of 16S rDNA, intI 1 and DOC can improve the ARGs removal effect of the combined process. Overall, the slow filtration-NF combined process is a better process for removing ARGs.

scholarly journals Removal of antibiotic resistance genes from secondary effluent by processes combining nano-iron, ultrasound-activated persulfate, and ultrafiltration

2021 ◽  
Author(s):  
Lihua Sun ◽  
Hao Tong ◽  
Cheng Gao ◽  
Yehui Liu ◽  
Cuimin Feng
Keyword(s):  
Antibiotic Resistance ◽  
Resistance Genes ◽  
Sewage Treatment ◽  
Antibiotic Resistance Genes ◽  
Oxidation Mechanism ◽  
Environmental Pollutant ◽  
Secondary Effluent ◽  
Class 1 Integron ◽  
Class 1 ◽  
Activated Persulfate

Abstract Antibiotic resistance genes (ARGs), as a new type of environmental pollutant which threaten human health, have been detected in the effluent of sewage treatment systems. In this study, the removal from water of ARGs, 16S rRNA, class 1 integron (intI1), and dissolved organic carbon (DOC) were investigated using processes combining nano-iron (nFe), ultrasound (US), activated persulfate (PS) and ultrafiltration (UF). The oxidation mechanism was also studied. The results showed that both nFe and US activation could improve the oxidative effect of PS, and the effect of nFe was better than that of US. Compared with PS-UF, nFe/PS-UF and US/PS-UF significantly enhanced the removal of various ARGs and DOC. nFe/PS-UF was the most effective treatment, reducing cell-associated and cell-free ARGs by 1.74–3.14-log and 1.00–2.61-log, respectively, while removing 30% of DOC. Pre-oxidation methods using PS, nFe/PS, and US/PS significantly enhanced the efficacy of UF for removing DOC with molecular weights above 50 kDa and below 10 kDa, but the removal of DOC between 10 and 50 kDa decreased. The free radicals SO4·− and ·OH were shown to participate in the process of ARGs oxidation.

scholarly journals Removal of Antibiotic Resistance Genes at Two Conventional Wastewater Treatment Plants of Louisiana, USA

Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1729 ◽  
Author(s):  
Ocean Thakali ◽  
John P. Brooks ◽  
Shalina Shahin ◽  
Samendra P. Sherchan ◽  
Eiji Haramoto
Keyword(s):  
Antibiotic Resistance ◽  
Wastewater Treatment ◽  
Resistance Genes ◽  
Wastewater Treatment Plants ◽  
Quantitative Polymerase Chain Reaction ◽  
Antibiotic Resistance Genes ◽  
Resistance Mechanisms ◽  
Secondary Effluent ◽  
Integrase Gene ◽  
Final Effluent

Wastewater treatment plants (WWTPs) represent all known types of antibiotic resistance mechanisms and are considered as the critical points for the spread of antibiotic resistance genes (ARGs). The purpose of this study is to investigate the removal of a Class 1 integrase gene (intI1) and a selected set of ARGs (blaTEM, ermF, mecA, and tetA) at two conventional WWTPs by using chlorination in Louisiana, USA. We collected 69 wastewater samples (23 each from influent, secondary effluent, and final effluent) and determined the concentrations of ARGs by using quantitative polymerase chain reaction. All tested ARGs, except for mecA, were detected in 83–96% and 30–65% of influent and final effluent samples, respectively. Although the ARGs underwent approximately 3-log10 reduction, two WWTPs on an average still released 3.3 ± 1.7 log10 copies/mL of total ARGs studied in the effluents. Chlorination was found to be critical in the significant reduction of total ARGs (p < 0.05). Correlation analysis and the ability of intI1 to persist through the treatment processes recommend the use of intI1 as a marker of ARGs in effluents to monitor the spread of antibiotic resistance in effluents. Our study suggests that conventional WWTPs using chlorination do not favor the proliferation of antibiotic resistance bacteria and ARGs during wastewater treatment.

scholarly journals Population Structure, Antibiotic Resistance, and Uropathogenicity of Klebsiella variicola

mBio ◽  
2018 ◽  
Vol 9 (6) ◽  
Author(s):  
Robert F. Potter ◽  
William Lainhart ◽  
Joy Twentyman ◽  
Meghan A. Wallace ◽  
Bin Wang ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Population Structure ◽  
Resistance Genes ◽  
Clinical Importance ◽  
Antibiotic Resistance Genes ◽  
Phylogenetic Structure ◽  
Content Type ◽  
Tract Infections

ABSTRACT Klebsiella variicola is a member of the Klebsiella genus and often misidentified as Klebsiella pneumoniae or Klebsiella quasipneumoniae. The importance of K. pneumoniae human infections has been known; however, a dearth of relative knowledge exists for K. variicola. Despite its growing clinical importance, comprehensive analyses of K. variicola population structure and mechanistic investigations of virulence factors and antibiotic resistance genes have not yet been performed. To address this, we utilized in silico, in vitro, and in vivo methods to study a cohort of K. variicola isolates and genomes. We found that the K. variicola population structure has two distant lineages composed of two and 143 genomes, respectively. Ten of 145 K. variicola genomes harbored carbapenem resistance genes, and 6/145 contained complete virulence operons. While the β-lactam blaLEN and quinolone oqxAB antibiotic resistance genes were generally conserved within our institutional cohort, unexpectedly 11 isolates were nonresistant to the β-lactam ampicillin and only one isolate was nonsusceptible to the quinolone ciprofloxacin. K. variicola isolates have variation in ability to cause urinary tract infections in a newly developed murine model, but importantly a strain had statistically significant higher bladder CFU than the model uropathogenic K. pneumoniae strain TOP52. Type 1 pilus and genomic identification of altered fim operon structure were associated with differences in bladder CFU for the tested strains. Nine newly reported types of pilus genes were discovered in the K. variicola pan-genome, including the first identified P-pilus in Klebsiella spp. IMPORTANCE Infections caused by antibiotic-resistant bacterial pathogens are a growing public health threat. Understanding of pathogen relatedness and biology is imperative for tracking outbreaks and developing therapeutics. Here, we detail the phylogenetic structure of 145 K. variicola genomes from different continents. Our results have important clinical ramifications as high-risk antibiotic resistance genes are present in K. variicola genomes from a variety of geographic locations and as we demonstrate that K. variicola clinical isolates can establish higher bladder titers than K. pneumoniae. Differential presence of these pilus genes inK. variicola isolates may indicate adaption for specific environmental niches. Therefore, due to the potential of multidrug resistance and pathogenic efficacy, identification of K. variicola and K. pneumoniae to a species level should be performed to optimally improve patient outcomes during infection. This work provides a foundation for our improved understanding of K. variicola biology and pathogenesis.

Quintuplex PCR to Detect Antibiotic Resistance Genes in Streptococcus pneumoniae

2016 ◽  
Vol 1 (2) ◽  
pp. 22 ◽  
Author(s):  
Navindra Kumari Palanisamy ◽  
Parasakthi Navaratnam ◽  
Shamala Devi Sekaran
Keyword(s):  
Antibiotic Resistance ◽  
Streptococcus Pneumoniae ◽  
Resistance Genes ◽  
Bacterial Pathogen ◽  
Antibiotic Resistance Genes ◽  
Pcr Amplification ◽  
Penicillin Resistance ◽  
Penicillin Binding Proteins ◽  
Efflux Mechanism ◽  
Mic Value

Introduction: Streptococcus pneumoniae is an important bacterial pathogen, causing respiratory infection. Penicillin resistance in S. pneumoniae is associated with alterations in the penicillin binding proteins, while resistance to macrolides is conferred either by the modification of the ribosomal target site or efflux mechanism. This study aimed to characterize S. pneumoniae and its antibiotic resistance genes using 2 sets of multiplex PCRs. Methods: A quintuplex and triplex PCR was used to characterize the pbp1A, ermB, gyrA, ply, and the mefE genes. Fifty-eight penicillin sensitive strains (PSSP), 36 penicillin intermediate strains (PISP) and 26 penicillin resistance strains (PRSP) were used. Results: Alteration in pbp1A was only observed in PISP and PRSP strains, while PCR amplification of the ermB or mefE was observed only in strains with reduced susceptibility to erythromycin. The assay was found to be sensitive as simulated blood cultures showed the lowest level of detection to be 10cfu. Conclusions: As predicted, the assay was able to differentiate penicillin susceptible from the non-susceptible strains based on the detection of the pbp1A gene, which correlated with the MIC value of the strains.

Sign in / Sign up

Export Citation Format

Share Document