Β-lactam Antibiotic Resistance Genes Research Articles

Unde venis? Bacterial resistance from environmental reservoirs to lettuce: tracking microbiome and resistome over a growth period.

Fresh produce is suggested to contribute highly to shaping the gut resistome. We investigated the impact of pig manure and irrigation water quality on microbiome and resistome of field-grown lettuce over an entire growth period. Lettuce was grown under four regimes, combining soil amendment with manure (with/without) with sprinkler irrigation using river water with an upstream wastewater input, disinfected by UV (with/without). Lettuce leaves, soil, and water samples were collected weekly and analyzed by bacterial cultivation, 16S rRNA gene amplicon sequencing, and shotgun metagenomics from total community DNA. Cultivation yielded only few clinically relevant antibiotic-resistant bacteria (ARB), but numbers of ARB on lettuce increased over time, while no treatment-dependent changes were observed. Microbiome analysis confirmed a temporal trend. Antibiotic resistance genes (ARGs) unique to lettuce and water included multidrug and β-lactam ARGs, whereas lettuce and soil uniquely shared mainly glycopeptide and tetracycline ARGs. Surface water carried clinically relevant ARB (e.g. ESBL-producing Escherichia coli or Serratia fonticola) without affecting the overall lettuce resistome significantly. Resistance markers including biocide and metal resistance were increased in lettuce grown with manure, especially young lettuce (increased soil contact). Overall, while all investigated environments had their share as sources of the lettuce resistome, manure was the main source especially on young plants. We therefore suggest minimizing soil-vegetable contact to minimize resistance markers on fresh produce.

Occurrence and distribution of antibiotic resistance genes in urban rivers with black-odor water of Harbin, China

Antibiotic resistance gene contamination in polluted rivers remains a widely acknowledged environmental issue. This study focused on investigating the contamination conditions of antibiotic resistance genes (ARGs) in Harbin’s urban black-odor rivers, specifically Dongfeng Ditch and Hejia Ditch. The research employed a SmartChip Real-Time PCR System to explore the types, abundance, and distribution of ARGs in diverse habitats, such as surface water and sediment. Additionally, the study examined the correlation of ARGs with mobile genetic elements (MGEs) and various environmental factors. It was found that antibiotic resistance genes were prevalent in both water and sediment within the black-odor ditches. The dominant types of ARGs identified included aminoglycoside, sulfonamide, multidrug-resistant, and β-lactam ARGs. Notably, the top four ARGs, in terms of relative abundance, were sul1, fox5, qacEdelta1-01 and aadA1. Most categories of ARGs have significant positive connections with MGEs, indicating that the enrichment and spreading of ARGs in rivers are closely related to MGEs. Based on the correlation analysis, it is found that environmental factors such as dissolved oxygen (DO), ammonia nitrogen (NH4–N), and phosphate (PO4–P) played a substantial role in influencing the variations observed in ARGs. By employing a risk assessment framework based on the human association, host pathogenicity, and mobility of ARGs, the identification of seven high-risk ARGs was achieved. In addition, it is important to assess the environmental risk of ARGs from multiple perspectives (abundance,detection rateand mobility). This study provides a significant reference regarding the presence of ARGs contamination in urban inland black-odor rivers, essential for assessing the health risks associated with ARGs and devising strategies to mitigate the threat of antibiotic resistance.

Genetic profile and characterization of antimicrobial resistance in Acinetobacter baumannii post-COVID-19 pandemic: a study in a tertiary hospital in Recife, Brazil.

To investigate the genetic profile and characterize antimicrobial resistance, including the main β-lactam antibiotic resistance genes, in Acinetobacterbaumannii isolates from a tertiary hospital in Recife-PE, Brazil, in the post-COVID-19 pandemic period. Acinetobacter baumannii isolates were collected between 2023 and 2024 from diverse clinical samples. Antimicrobial resistance testing followed standardized protocols, with β-lactamase-encoding genes detected via PCR and sequencing. Investigation into ISAba1 upstream of blaOXA-carbapenemase and blaADC genes was also conducted. Genetic diversity was assessed through ERIC-PCR. Among the 78 A. baumannii, widespread resistance to multiple antimicrobials was evident. Various acquired β-lactamase-encoding genes (blaOXA-23,-24,-58,-143, blaVIM, and blaNDM) were detected. Furthermore, this is the first report of blaVIM-2 in A. baumannii isolates harboring either the blaOXA-23-like or the blaOXA-143 gene in Brazil. Molecular typing revealed a high genetic heterogeneity among the isolates, and multi-clonal dissemination. The accumulation of genetic resistance determinants underscores the necessity for stringent infection control measures and robust antimicrobial stewardship programs to curb multidrug-resistant strains.

Microplastics in anoxic/aerobic membrane bioreactor (A/O-MBR): Characteristics, biofilms, degradation and carrier for antibiotic resistance genes

Wastewater treatment plants (WWTPs)are proposed as one of the ways for microplastics (MPs) to enter the water environment. MPs as the carrier of other pollutants, the inevitable aging process will change the characteristics and fate of MPs. Herein, the physicochemical property alteration, microbial community evolution and antibiotic resistance genes (ARGs) occurrence of the aged MPs surface were analyzed in A/O-MBR system. Remarkable alteration in MPs surface properties, which included the decrease in hydrophobicity and the increase in oxygen-containing functional groups, led to aging of MPs. Aging MPs are more likely to grow biofilms, which further increased the probability of microbial colonization. The genera Hydrogenophaga, Exiguobacterium, Enterobacter, Vibrio, Flavobacterium and Bacillus on MPs surface showed higher degradation potential. ARGs determination results indicated that MPs could enrich ARGs on their surface, and the relative abundance of β-lactam ARGs on different MPs surfaces was the highest. The above research results indicated that MPs in sewage treatment systems not only undergo aging, but also carry ARGs, causing further harm to the environment.

Analysis of Bacterial Communities and Antibiotic Resistance Genes in the Aquaculture Area of Changli County

In order to understand the distribution of microorganisms and various antibiotic resistance genes in the aquaculture area of Changli County, Qinhuangdao, high-throughput sequencing technology was used in this study. We utilized 16S rDNA gene sequencing and metagenome sequencing methods to analyze the seawater, sediment, and gut contents of the local fish Synechogobius hasta in the aquaculture area in spring. The results showed that Proteobacteria, Firmicutes, and Bacteroidota were the dominant bacteria in seawater; and Proteobacteria, Crenarchaeota, Acidobacter, and Actinobaciota were rich in the sediment; whereas Proteobacteria, Cyanobacteria, Firmicutes, and Bacteroidota were in relatively high abundance in fish gut contents. The microbial diversity of sediment samples was the most abundant, followed by seawater samples, and the microbial diversity of fish intestinal contents was the lowest. Moreover, the microbial diversity of similar samples was relatively similar, and the microbial diversity of different types of samples was quite different. For samples at different sites, there were significant differences between seawater samples at each site, and there were small differences between sediment samples at each site, and some sediment sample groups did not have significant differences in microbial composition. In all sample groups, five β-lactam antibiotic resistance genes (blaOXA-325, cepS, blaCARB-20, blaOXA-55, and blaTRU-1) and four aminoglycoside antibiotic resistance genes[aac(6')-IIb, amrA, aac(6')-Ie-aph(2″)-Ia, and aph(3')-Vc] were detected. There was also a certain correlation between antibiotic resistance genes and microbial communities.

Mechanisms of total phosphorus removal and reduction of β-lactam antibiotic resistance genes by exogenous fungal combination activated sludge

This study utilized Trichoderma and activated sludge to construct combined activated sludge (TAS). The metagenomic approach was employed to examine the shifts in microbial community structure and function of TAS under amoxicillin stress and investigate the mechanism underlying the reduction of β-lactam antibiotic resistance genes (β-ARGs). The findings demonstrated that the elevated aundance of glpa, glpd, ugpq, glpq, and glpb were primarily responsible for the reduction in total phosphorus (TP) removal by TAS. The increased abundance of Proteobacteria and Verrucomicrobia led to enhanced expression of ugpb, phnd, and phne, thereby improving the TP removal of TAS. Furthermore, antibiotic inactivation has gradually become the primary antibiotic resistance mechanism in TAS. Specifically, an increase in the abundance of OXA-309 in TAS will decrease the probability of amoxicillin accumulation in TAS. A decrease in β-ARGs diversity confirmed this. This study presents a novel approach to reducing antibiotic and ARG accumulation in sludge.

Multidrug-resistant Enterobacter spp. in wastewater and surface water: Molecular characterization of β-lactam resistance and metal tolerance genes

Among the ESKAPE group pathogens, Enterobacter spp. is an opportunistic Gram-negative bacillus, widely dispersed in the environment, that causes infections. In the present study, samples of hospital wastewater, raw and treated urban wastewater, as well as surface receiving water, were collected to assess the occurrence of multidrug-resistant (MDR) Enterobacter spp. A molecular characterization of β-lactam antibiotic resistance and metal tolerance genes was performed. According to identification by MALDI-TOF MS, 14 isolates were obtained: 7 E. bugandensis, 5 E. kobei, and 2 E. cloacae. The isolates showed resistance mainly to β-lactam antibiotics, including those used to treat infections caused by MDR bacteria. Multiple antibiotic resistance index was calculated for all isolates. It allowed verify whether sampling points showed a high risk due to antibiotic resistant Enterobacter spp., as well as to determine if the isolates have been in environments with a frequent antibiotic use. Twelve isolates showed β-lactam antibiotic resistance gene, being the blaKPC widely detected. Regarding metal tolerance, 13 isolates showed at least two genes that encode metal tolerance mechanisms. Overall, metal tolerance mechanisms to silver, copper, mercury, arsenic and tellurium were found. New data on metal tolerance mechanisms dispersion and antibiotic-resistance characterization of the E. bugandensis and E. kobei species were here provided. The occurrence of MDR Enterobacter spp. in analyzed samples draws attention to an urgent need to put control measures into practice. It also evidences waterborne spread of clinically important antibiotic-resistant bacteria recognized as critical priority pathogens.

Urbanization led to the abundance of Gram-negative, chemo-organo-heterotrophs, and antibiotic resistance genes in the downstream regions of the Ganga River water of India.

The present investigation assesses the bacterial microbiome and antibiotic resistance genes (ARGs) of the river Ganga from Uttarakhand (upstream region; US group) and Uttar Pradesh (downstream region; DS group) regions using a 16S rRNA amplicon-based metagenomic approach. Gram-negative, aerobic, and chemo-organotrophic bacteria made up the majority of the bacterial genera during the overall analysis. Physicochemical analysis revealed a higher concentration of nitrate and phosphate in the downstream sites of the Ganga River. The prevalence of Gemmatimonas, Flavobacterium, Arenimonas, and Verrucomicrobia in the water of the DS region indicates a high organic load. Pseudomonas and Flavobacterium emerged as the most prevalent genera among the 35 significantly different shared genera (p-value < 0.05) in the US and DS regions, respectively. Overall antibiotic resistance analysis of the samples showed the dominance of β-lactam resistance (33.92%) followed by CAMP (cationic antimicrobial peptide) resistance (27.75%), and multidrug resistance (19.17%), vancomycin resistance (17.84%), and tetracycline resistance (0.77%). While comparing, the DS group exhibited a higher abundance of ARGs over the US group, where the CAMP resistance and β-lactam ARGs were dominant in the respective regions. The correlation (p-value < 0.05) analysis showed that most bacteria exhibit a significant correlation with tetracycline resistance followed by the phenicol antibiotic. The present findings draw attention to the need for regulated disposal of multiform human-derived wastes into the Ganga River to reduce the irrepressible ARGs dissemination.

Phenotypic diagnosis and genotypic identification of Bacillus cereus causing subclinical mastitis in cows.

Bovine mastitis is a disease that affects dairy cows and impacts the global dairy industry. Bacillus spp. can infect the mammary gland during lactation, intramammary treatment, or dry cow therapy. This study aimed to isolate and identify Bacillus spp. in raw milk samples from cows with subclinical mastitis from dairy farms in Beheira, Giza, Alexandria, and Menoufia Governorate, Egypt. We also investigated their antibiotic sensitivity and detected the enterotoxigenic and antibiotic resistance genes. A total of 262 milk samples (15-20 ml each) were examined microscopically, biochemically, and phenotypically. A polymerase chain reaction was used for genotypic identification and detecting antibiotic-resistance and enterotoxigenic genes. Antibiotic sensitivity was tested using the agar well diffusion test. Bacillus cereus was identified in 47.7% of samples. Nhe and hblD enterotoxin genes were found in 93.64% (103/110) and 91.82% (101/110) of the samples, respectively. Tetracycline and β-lactam antibiotic-resistance genes were present in 0% (0/110) and 98.18% (108/110), respectively, of the samples. All isolates were resistant to cefepime, cefixime, and oxacillin, while they were susceptible to amoxicillin-clavulanic, chloramphenicol, ampicillin/sulbactam, and levofloxacin. These results highlight the need to promote awareness regarding B. cereus, the most common pathogen causing mastitis in Egyptian dairy cows. We also emphasized that antibiotic misuse during mastitis is a potential public health threat.

Periodontal pathogens and antibiotic resistance genes in individuals with chronic generalized periodontitis

Relevance. Considering the role of personalized medicine in dental practice, the accumulation of knowledge about the genetic determinants of bacterial resistance and the use of antibacterial drugs, the learning of periodontal microbiota, sensitivity to antimicrobial drugs, the identification of key periodontal pathogens will allow predicting the development mechanisms of inflammatory periodontal diseases and monitoring and prescribing effective antibacterial therapy.Aim. The study aimed to determine the prevalence of pathogens and the occurrence of antibiotic resistance genes in individuals with chronic generalized periodontitis (CGP).Materials and methods. Clinical and laboratory examinations studied 163 subjects aged 18 to 45 years, of which there were 100 patients with inflammatory periodontal diseases and 63 subjects with intact periodontium. The study obtained periodontal pocket and gingival crevice swabs. The real-time PCR isolated marker bacteria and resistance genes to glycopeptide and β-lactam antibiotics.Results. The patients with chronic periodontitis demonstrated a periodontal pathogen detection rate of 96.4 %. Among the isolated periodontal pathogens, bacteria of the red complex were the most common: T. forsythia (81%; p &lt; 0.001), T. denticola (63%; p = 0.054) and P. gingivalis (69%; p &lt; 0.001). In healthy individuals with intact periodontium, P. gingivalis (12.7%), T. denticola (47.62%), and T. forsythia (36.51%) prevailed in the studied material, i.e., gingival fluid. The mean ratio of bone loss in relation to the root length (the Fuchs Index) was 0.83 ± 0.03 in patients with mild CGP and 0.71 ± 0.05 with moderate CGP. The β-lactam antibiotic resistance genes appeared to occur frequently (%). So, TEM and SHV genes were in 72% and 26%. The control group demonstrated the TEM gene in 41.27% (p &lt; 0.001) and the SHV gene in 4.76% (p &lt; 0.001).The group with CGP appeared to have resistance genetic markers: MecA to cephalosporins (15%) and OXA-51 to carbapenems (9%). The control group detected MecA (6.35%; p = 0.0948), while OXA-51 markers were absent (p = 0.014). Both groups did not show resistance genes to other antibiotic groups (AB).Conclusion. The "red complex" microorganisms T. forsythia, T. denticola and P. gingivalis, which were the most frequent during the progression of bone destruction, appeared to play the leading role in the onset and progression of inflammatory periodontal diseases.The oral microbiome can serve as a reservoir for the transfer of resistance genes: the study results indicate a high incidence rate (%) of β-lactam antibiotic resistance genes in the group of patients with chronic periodontitis. The group with chronic periodontitis revealed TEM and SHV genes in 72% and 26%, respectively. The group with intact periodontium also demonstrated a high occurrence rate of the TEM gene in 58.3 % of cases.

The gastrointestinal antibiotic resistome in pediatric leukemia and lymphoma patients.

Most children with leukemia and lymphoma experience febrile neutropenia. These are treated with empiric antibiotics that include β-lactams and/or vancomycin. These are often administered for extended periods, and the effect on the resistome is unknown. We examined the impact of repeated courses and duration of antibiotic use on the resistome of 39 pediatric leukemia and lymphoma patients. Shotgun metagenome sequences from 127 stool samples of pediatric oncology patients were examined for abundance of antibiotic resistance genes (ARGs) in each sample. Abundances were grouped by repeated courses (no antibiotics, 1-2 courses, 3+ courses) and duration (no use, short duration, long and/or mixed durationg) of β-lactams, vancomycin and "any antibiotic" use. We assessed changes in both taxonomic composition and prevalence of ARGs among these groups. We found that Bacteroidetes taxa and β-lactam resistance genes decreased, while opportunistic Firmicutes and Proteobacteria taxa, along with multidrug resistance genes, increased with repeated courses and/or duration of antibiotics. Efflux pump related genes predominated (92%) among the increased multidrug genes. While we found β-lactam ARGs present in the resistome, the taxa that appear to contain them were kept in check by antibiotic treatment. Multidrug ARGs, mostly efflux pumps or regulators of efflux pump genes, were associated with opportunistic pathogens, and both increased in the resistome with repeated antibiotic use and/or increased duration. Given the strong association between opportunistic pathogens and multidrug-related efflux pumps, we suggest that drug efflux capacity might allow the opportunistic pathogens to persist or increase despite repeated courses and/or duration of antibiotics. While drug efflux is the most direct explanation, other mechanisms that enhance the ability of opportunistic pathogens to handle environmental stress, or other aspects of the treatment environment, could also contribute to their ability to flourish within the gut during treatment. Persistence of opportunistic pathogens in an already dysbiotic and weakened gastrointestinal tract could increase the likelihood of life-threatening blood borne infections. Of the 39 patients, 59% experienced at least one gastrointestinal or blood infection and 60% of bacteremia's were bacteria found in stool samples. Antimicrobial stewardship and appropriate use and duration of antibiotics could help reduce morbidity and mortality in this vulnerable population.

Beta-Lactam Antibiotic Resistance Genes in the Microbiome of the Public Transport System of Quito, Ecuador.

Multidrug-resistant bacteria present resistance mechanisms against β-lactam antibiotics, such as Extended-Spectrum Beta-lactamases (ESBL) and Metallo-β-lactamases enzymes (MBLs) which are operon encoded in Gram-negative species. Likewise, Gram-positive bacteria have evolved other mechanisms through mec genes, which encode modified penicillin-binding proteins (PBP2). This study aimed to determine the presence and spread of β-lactam antibiotic resistance genes and the microbiome circulating in Quito's Public Transport (QTP). A total of 29 station turnstiles were swabbed to extract the surface environmental DNA. PCRs were performed to detect the presence of 13 antibiotic resistance genes and to identify and to amplify 16S rDNA for barcoding, followed by clone analysis, Sanger sequencing, and BLAST search. ESBL genes blaTEM-1 and blaCTX-M-1 and MBL genes blaOXA-181 and mecA were detected along QPT stations, blaTEM being the most widely spread. Two subvariants were found for blaTEM-1, blaCTX-M-1, and blaOXA-181. Almost half of the circulating bacteria found at QPT stations were common human microbiota species, including those classified by the WHO as pathogens of critical and high-priority surveillance. β-lactam antibiotic resistance genes are prevalent throughout QPT. This is the first report of blaOXA-181 in environmental samples in Ecuador. Moreover, we detected a new putative variant of this gene. Some commensal coagulase-negative bacteria may have a role as mecA resistance reservoirs.

Response of Antibiotic Resistance Genes and Related Microorganisms to Arsenic during Vermicomposting of Cow Dung.

Antibiotic resistance pollution in livestock manure is a persistent issue that has drawn public attention. Vermicomposting is an ecofriendly biological process that can render livestock manure harmless and resourceful. However, little is known about the impact of vermicomposting on antibiotic resistance in livestock manure under stress caused by potentially toxic arsenic levels. Herein, lab-scale vermicomposting was performed to comprehensively evaluate the shift in antibiotic resistance genes (ARGs) and related microorganisms in fresh earthworm casts as well as vermicompost product health (i.e., nutrient availability and enzyme activity) when they were fed on arsenic-contaminated cow manure. The results showed that the earthworms' interaction with cow dung led to a significant reduction in ARG concentrations, especially for tetracycline ARGs (tet-ARGs), β-lactam ARGs (bla-ARGs), and quinolone ARGs (qnr-ARGs). However, arsenic significantly enhanced ARG accumulation in earthworm casts in a dose-dependent manner. Moreover, vermicomposting increased the percentage of Bacteroidota in the converted products. Furthermore, arsenic exposure at low concentrations promoted the proliferation of Proteobacteria, whereas high concentrations had little effect on Proteobacteria. Our study provides valuable insight into the changes in the antibiotic resistome and related microorganisms during vermicomposting of arsenic-amended cow manure, and it is crucial to explain the environmental impact of earthworms and improve our understanding of the reciprocal benefits of soil invertebrates.

Enhanced removal of antibiotic resistance genes and human bacterial pathogens during anaerobic digestion of dairy manure via addition of manure biochar.

In this study, the response of antibiotic resistance genes (ARGs), mobile gene elements (intI1), and human bacterial pathogens (HBPs) to addition of manure biochar (1-10g/L) was studied in anaerobic digestion (AD) at 20-55°C for treating dairy manure. Twelve ARGs comprising five tetracycline resistance genes, two sulfonamide resistance genes, two macrolide resistance genes, three β-lactam antibiotic resistance genes, and intI1 were analyzed by quantitative PCR. High-throughput sequencing data were matched against a database of putative 538 HBPs. Significant removal of ARGs (except for tetO and ermB) and intI1 was observed in all the samples. Manure biochar resulted in significant removal of ARGs and HBPs; however, negative effects were also observed in some conditions. This is the first study to provide to explore the fates of ARGs and HBPs by adding manure biochar to AD.

Prevalence of antibiotic resistance genes in drinking and environmental water sources of the Kathmandu Valley, Nepal.

Antibiotic-resistant bacteria-associated infections are responsible for more than 1.2 million annual deaths worldwide. In low- and middle-income countries (LMICs), the consumption of antibiotics for human and veterinary uses is not regulated effectively. Overused and misused antibiotics can end up in aquatic environments, which may act as a conduit for antibiotic resistance dissemination. However, data on the prevalence of antibiotic resistance determinants in aquatic environments are still limited for LMICs. In this study, we evaluated the prevalence and concentration of antibiotic resistance genes (ARGs) in different drinking and environmental water sources collected from the Kathmandu Valley, Nepal, using droplet digital polymerase chain reaction to understand the current situation of ARG contamination. River water and shallow dug well water sources were the most contaminated with ARGs. Almost all samples contained sul1 (94%), and intI1 and tet(A) were detected in 83 and 60% of the samples, respectively. Maximum ARG concentration varied between 4.2 log10 copies/100 ml for mecA and 9.3 log10 copies/100 ml for sul1. Significant positive correlations were found between ARGs (r > 0.5, p < 0.01), except for mecA, qnrS, and vanA. As sul1 and intI1 were detected in almost all samples, the presence of these genes in a given sample may need to be considered as background antibiotic resistance in LMICs. Therefore, monitoring of ARGs, such as β-lactam ARGs, quinolone resistance genes, and vancomycin resistance genes, may provide a better picture of the antibiotic resistance determinants in aquatic environments of LMICs.

β-lactamase genes transmission influenced by tetracycline, sulfonamide and β-lactams antibiotics contamination in the on-site farm soil

The prevalence of antibiotic resistance genes (ARGs), which have been identified as emerging environmental pollutants that pose a considerable risk to human health is widespread. The formation and transmission of ARGs are mainly associated with the antibiotic stress in an environment. And the abundance of ARGs also influenced by other categories antibiotics. The geographic information system was used to visualize the relative abundance of 28 types of ARGs and concentration of 18 types of antibiotics. The concentration of tetracycline antibiotics (TCs) and sulfonamide antibiotics (SAs) decreased gradually with increasing soil depth, while that of β-lactams (β-Ls) showed an increasing trend. The results revealed that TCs accounted for the largest proportion of all antibiotics. Furthermore, the abundance of β-lactam ARGs (β-RGs) increased with TCs and β-Ls increased. The abundance of tetracycline ARGs (TRGs) remained relatively stable with increasing concentrations of all antibiotics, while that of sulfonamide ARGs (SRGs) showed a decreasing trend. Although the abundance of β-RGs significantly increased with increasing levels of TCs and β-Ls. However, β-RGs were not significantly correlated with β-Ls, but with TCs. This study provided visual and comprehensive insights into the correlation between the distribution of typical antibiotics and ARGs and analyzed the synergy or antagonism between different antibiotics and ARGs. It is significant for soil remediation to reduce the likelihood of ARGs entering into and spreading in the human food chain via milk and beef consumption.

Seasonal Variation and Influencing Factor Analysis of Antibiotic Resistance Genes in Water Supply Reservoirs of Central China

This study quantified an integron gene intI1 and 19 antibiotic resistance genes(ARGs) to identify the ARGs pollution characteristics in 11 drinking water reservoirs of central China. The results indicated that the ARGs abundance did not change significantly over time in the studied reservoir waterbodies. Tetracycline, sulfonamide, and β-lactam ARGs were dominant. The high abundance and detection rate of two sulfonamide ARGs(sul1 and sul2) suggested that they were the predominant ARGs. No polymyxin resistance genes(mcr-1) were detected, which indicated that the antibiotic restriction policy of China has achieved positive outcomes. Compared with that in other environmental media, the ARGs abundance in the reservoir environment was low. The correlation analysis showed relevance between the water quality indicators and the ARGs, which suggested that the water quality indexes can be used as ARGs pollution indicators in the reservoir environment. The abundance and detection rate of carbapenem ARGs were low owing to their dosage restriction and high degradability. Tetracycline ARGs were closely related to the other resistance gene types, which might have been due to horizontal gene transfer. Although the overall correlation between intI1 and ARGs was modest, it might be the main reason for the spread of several individual ARGs in the reservoir environment.

Tracing Antibiotic Resistance Genes along the Irrigation Water Chain to Chive: Does Tap or Surface Water Make a Difference?

Irrigation water is well known as potential source of pathogens in fresh produce. However, its role in transferring antibiotic resistance determinants is less well investigated. Therefore, we analyzed the contribution of surface and tap water to the resistome of overhead-irrigated chive plants. Field-grown chive was irrigated with either surface water (R-system) or tap water (D-system), from planting to harvest. Water along the two irrigation chains as well as the respective plants were repeatedly sampled and screened for 264 antibiotic resistance genes (ARGs) and mobile genetic elements (MGEs), using high-capacity qPCR. Differentially abundant (DA) ARGs were determined by comparing the two systems. On R-chive, β-lactam ARGs, multidrug-resistance (MDR) determinants, and MGEs were most abundant, while D-chive featured DA ARGs from the vancomycin class. Diversity and number of DA ARGs was the highest on young chives, strongly diminished at harvest, and increased again at the end of shelf life. Most ARGs highly enriched on R- compared to D-chive were also enriched in R- compared to D-sprinkler water, indicating that water played a major role in ARG enrichment. Of note, blaKPC was detected at high levels in surface water and chive. We conclude that water quality significantly affects the resistome of the irrigated produce.

The Epidemiology, Virulence and Antimicrobial Resistance of Invasive Klebsiella pneumoniae at a Children’s Medical Center in Eastern China

ObjectiveThis study investigated the epidemiology, virulence and drug resistance of invasive Klebsiella pneumoniae (K. pneumoniae) isolates at a children’s medical center in eastern China in order to obtain epidemiologic, virulence, and antimicrobial resistance data that can guide for the selection and development of anti-infection treatments.MethodsA total of 94 invasive K. pneumoniae strains were isolated from children between January 2016 and December 2020 at the Children’s Hospital of Soochow University. The strains were identified by mass spectrometry. The Kirby–Bauer method and VITEK 2 Compact system were used to analyze the antimicrobial susceptibility. Polymerase chain reaction (PCR) and sequencing was performed to detect the capsular serotypes, virulence-associated genes, β-lactam antibiotic resistance genes and multilocus sequence typing.ResultsThe PCR results showed that 87 strains (92.55%) of invasive K. pneumoniae were hypervirulent capsular serotypes, with K57 as the dominant capsular serotype (62.77%). All strains carried virulence-associated genes. Among them, 84 strains (89.36%) carried hypervirulence genes, with iroB (86.17%) being the predominant; meanwhile, other virulence genes, including wabG (100.00%), mrkD (98.94%), ycfM (96.81%), fimH (95.74%) and Uge (88.30%), were detected in most strains. All strains carried β-lactam antibiotic resistance genes; the main extended-spectrum β-lactamase gene was blaSHV-11 (86.17%) and the major AmpC cephalosporinase genes were blaFOX-1 (86.17%) and blaACT-1 (70.21%). Carbapenemase genes were detected in only a few isolates. Notably, 12 invasive K. pneumoniae isolates were identified as carbapenem-resistant and hypervirulent K. pneumoniae (CR-HVKP), and 14 other multidrug resistance (MDR) isolates were also detected.ConclusionThe results of this study reveal the epidemiology, virulence and antimicrobial resistance of invasive K. pneumoniae in pediatric patients. Both CR-HVKP and MDR strains were identified, which should be of great concern to clinicians.

Demonstrating an Integrated Antibiotic Resistance Gene Surveillance Approach in Puerto Rican Watersheds Post-Hurricane Maria.

Comprehensive surveillance approaches are needed to assess sources, clinical relevance, and mobility of antibiotic resistance genes (ARGs) in watersheds. Here, we examined metrics derived from shotgun metagenomic sequencing and relationship to human fecal markers (HFMs; crAssphage, enterococci) and anthropogenic antibiotic resistance markers (AARMs; intI1, sul1) in three distinct Puerto Rican watersheds as a function of adjacent land use and wastewater treatment plant (WWTP) input 6 months after Hurricane Maria, a category V storm. Relative abundance and diversity of total ARGs increased markedly downstream of WWTP inputs, with ARGs unique to WWTP and WWTP-impacted river samples predominantly belonging to the aminoglycoside and β-lactam resistance classes. WWTP and other anthropogenic inputs were similarly associated with elevated resistome risk scores and mobility incidence (M%). Contig analysis indicated a wide variety of mobile β-lactam ARGs associated with pathogens downstream of WWTP discharge that were consistent with regional clinical concern, e.g., Klebsiella pneumoniae contigs containing KPC-2 within an ISKpn6-like transposase. HFMs and AARMs correlated strongly with the absolute abundance of total ARGs, but AARMs better predicted the majority of ARGs in general (85.4 versus <2%) and β-lactam ARGs in particular. This study reveals sensitive, quantitative, mobile, clinically relevant, and comprehensive targets for antibiotic resistance surveillance in watersheds.