Prevalence Of Resistance Genes Research Articles

Current examining methods and mathematical models of horizontal transfer of antibiotic resistance genes in the environment.

The increasing prevalence of antibiotic resistance genes (ARGs) in the environment has garnered significant attention due to their health risk to human beings. Horizontal gene transfer (HGT) is considered as an important way for ARG dissemination. There are four general routes of HGT, including conjugation, transformation, transduction and vesiduction. Selection of appropriate examining methods is crucial for comprehensively understanding characteristics and mechanisms of different HGT ways. Moreover, combined with the results obtained from different experimental methods, mathematical models could be established and serve as a powerful tool for predicting ARG transfer dynamics and frequencies. However, current reviews of HGT for ARG spread mainly focus on its influencing factors and mechanisms, overlooking the important roles of examining methods and models. This review, therefore, delineated four pathways of HGT, summarized the strengths and limitations of current examining methods, and provided a comprehensive summing-up of mathematical models pertaining to three main HGT ways of conjugation, transformation and transduction. Finally, deficiencies in current studies were discussed, and proposed the future perspectives to better understand and assess the risks of ARG dissemination through HGT.

Prevalence of Plasmid-Mediated Quinolone Resistance Genes in Pseudomonas aeruginosa Clinical Strains in Northwest Iran

Prevalence of Plasmid-Mediated Quinolone Resistance Genes in Pseudomonas aeruginosa Clinical Strains in Northwest Iran

Temporal Dynamics and Contribution of Phage Community to the Prevalence of Antibiotic Resistance Genes in a Full-Scale Sludge Anaerobic Digestion Plant.

Anaerobic digestion (AD) is an important biological resource recovery process, where microorganisms play key roles for material transformation. There has been some knowledge about the prokaryotic community and antibiotic resistance genes (ARGs) in AD, but there has been very limited knowledge of phages. In this study, samples from a full-scale AD plant were collected over 13 months, sequenced, and analyzed for viral and prokaryotic metagenomes. Totally, 3015 viral operational taxonomic units (vOTUs) were detected, mostly assigned to Caudoviricetes. The phage community had faster temporal variation than the prokaryotic community. Warm seasons harbored a higher abundance of both temperate phages and broad host-range phages. Seven ARGs of 6 subtypes were carried by 20 vOTUs, a representative ermT gene was synthesized and expressed, and the resistance activity in the host was examined, confirming the real activity of virus-carried ARGs in the AD process. Some of the ARGs were horizontally transferred between the phage and prokaryotic genomes. However, phage infection was not found to contribute to ARG transfer. This study provided an insight into the ecological patterns of the phage community, confirmed the antibiotic resistance activity of virus-carried ARGs, evaluated the contribution of phages on the ARG prevalence, and laid the foundation for the control strategies of the community and antibiotic resistance in the AD process.

Distribution of resistance genes and resistance profile of methicillin-resistant Staphylococcus aureus among animal handlers in Animal Market, Jos

The problems associated with bacteria resistance to antibiotics are increasing despite spirited efforts to overcome the menace and its many attendants’ negative implications on human health and the related burden of failure by health institutions. The study characterized and determined the prevalence of resistance genes among animal handlers in livestock markets within Jos, Nigeria. Nose lining secretions and skin surface samples (384) were collected and bacteria were isolated from them. Isolates were characterized for methicillin and multidrug resistance, after which mecA and mecC presence was determined using molecular method. Seven bacterial species were isolated with the genus Staphylococcus having two species had 52.0% prevalence on skin surface and in nasal secretions. Thirty-three Staphylococcus aureus isolates were methicillin-resistant, and 37 skin surface and 34 nose secretions isolates were multidrug-resistant. mecA genes were present in 18 methicillin-resistant Staphylococcus aureus isolates obtained from the skin surface and 12 isolates from the nose lining. The study confirmed the presence of a high number of methicillin-resistant Staphylococcus aureus (MRSA) with mecA resistance regulatory gene.

Analysis of Antimicrobial Resistance in Bacterial Pathogens Recovered from Food and Human Sources: Insights from 639,087 Bacterial Whole-Genome Sequences in the NCBI Pathogen Detection Database.

Understanding the role of foods in the emergence and spread of antimicrobial resistance necessitates the initial documentation of antibiotic resistance genes within bacterial species found in foods. Here, the NCBI Pathogen Detection database was used to query antimicrobial resistance gene prevalence in foodborne and human clinical bacterial isolates. Of the 1,843,630 sequence entries, 639,087 (34.7%) were assigned to foodborne or human clinical sources with 147,788 (23.14%) from food and 427,614 (76.88%) from humans. The majority of foodborne isolates were either Salmonella (47.88%), Campylobacter (23.03%), Escherichia (11.79%), or Listeria (11.3%), and the remaining 6% belonged to 20 other genera. Most foodborne isolates were from meat/poultry (95,251 or 64.45%), followed by multi-product mixed food sources (29,892 or 20.23%) and fish/seafood (6503 or 4.4%); however, the most prominent isolation source varied depending on the genus/species. Resistance gene carriage also varied depending on isolation source and genus/species. Of note, Klebsiella pneumoniae and Enterobacter spp. carried larger proportions of the quinolone resistance gene qnrS and some clinically relevant beta-lactam resistance genes in comparison to Salmonella and Escherichia coli. The prevalence of mec in S. aureus did not significantly differ between meat/poultry and multi-product sources relative to clinical sources, whereas this resistance was rare in isolates from dairy sources. The proportion of biocide resistance in Bacillus and Escherichia was significantly higher in clinical isolates compared to many foodborne sources but significantly lower in clinical Listeria compared to foodborne Listeria. This work exposes the gaps in current publicly available sequence data repositories, which are largely composed of clinical isolates and are biased towards specific highly abundant pathogenic species. We also highlight the importance of requiring and curating metadata on sequence submission to not only ensure correct information and data interpretation but also foster efficient analysis, sharing, and collaboration. To effectively monitor resistance carriage in food production, additional work on sequencing and characterizing AMR carriage in common commensal foodborne bacteria is critical.

Understanding associations between antimicrobial agents usage and antimicrobial resistance genes prevalence at the community level using wastewater-based epidemiology: A Spanish pilot study

Understanding the development and spread of antimicrobial resistance (AMR) is important for combating this global threat for public health. Wastewater-based epidemiology (WBE) is a complementary approach to current surveillance programs that minimizes some of the existing limitations. The aim of the present study is to explore WBE for monitoring antibiotics and antibiotic resistance genes (ARGs) in wastewater samples collected during 2021/2022 from the city of Castellon (Spain). Eighteen commonly prescribed antibiotics have been selected and measured by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS), with triple quadrupole mass analysers. Moreover, qPCR for specific ARGs has been performed to obtain information of these genes in co-presence with antibiotics. All selected ARGs, along with a total of 11 antibiotics, were identified. The highest population-normalized daily loads were observed for the macrolide azithromycin, followed by the quinolones ciprofloxacin and levofloxacin. Subsequently, daily consumption estimates based on wastewater data were compared with prescription data of antibiotics. Statistical analyses were conducted to explore if there is correlation between antibiotics and ARGs. While no correlations were found between antibiotics and their corresponding ARGs, certain correlations (p < 0.05) were identified among non-corresponding ARGs. In addition, a strong positive correlation was found between the sum of all antibiotics and the intl1 gene. Moreover, population-normalized ARG loads significantly correlate with the 16S rRNA-normalized ARG loads, serving as an indicator for population size. Results provide a baseline for future work and a proof-of-concept emphasising the need for future work and long-term surveillance, and highlight the need of similar programs at a regional and global levels worldwide.

Hygiene practices and antibiotic resistance among dental and medical students: a comparative study.

Healthcare students' hand and smartphone hygiene is critical due to potential pathogenic and antibiotic-resistant bacteria transmission. This study evaluates hygiene practices in medical and dental students at Kuwait University, exploring antibiotic resistance gene prevalence. Swab samples were collected from the hands and smartphones of 32 medical and 30 dental students. These samples were cultured on Columbia Blood Agar and McConkey Agar plates to quantify bacterial colony-forming units (CFUs). The extracted DNA from these colonies underwent RT-PCR to identify antibiotic resistance genes, including tem-1, shv, blaZ, and mecA. Additionally, a questionnaire addressing hygiene practices was distributed post-sample collection. Medical students exhibited more frequent hand hygiene compared to dental students (P ≤ 0.0001). Although significantly fewer bacterial CFUs were found on medical students' smartphones (mean = 35 ± 53) than dental students' (mean = 89 ± 129) (P ≤ 0.05), no significant differences were observed in CFU counts on their hands (medical: mean = 17 ± 37; dental: mean = 96 ± 229). Detection of at least one of the targeted antibiotic resistance genes on medical (89% hands, 52% smartphones) and dental students' (79% hands, 63% smartphones) was not statistically significant. However, the prevalence of two genes, tem-1 and shv, was significantly higher on medical students' hands (78% and 65%, respectively) than on dental students' hands (32% and 28%, respectively). Clinically significant prevalence of antibiotic resistance genes were found on medical and dental students' hands and smartphones, emphasizing the importance of ongoing education regarding hand hygiene and smartphone disinfection. This continuous reinforcement in the curriculum is crucial to minimizing the risk of cross-contamination.

Antimicrobial resistance landscape in a metropolitan city context using open drain wastewater-based metagenomic analysis

One Health concept recognizes the inextricable interactions of diverse ecosystems and their subsequent effect on human, animal and plant health. Antimicrobial resistance (AMR) is a major One Health concern and is predicted to cause catastrophes if appropriate measures are not implemented. To understand the AMR landscape in a south Indian metropolitan city, metagenomic analysis of open drains was performed. The data suggests that in January 2022, macrolide class of antibiotics contributed the highest resistance of 40.1% in the city, followed by aminoglycoside- 24.4%, tetracycline- 11.3% and lincosamide- 6.7%. The ‘mutations in the 23S rRNA gene conferring resistance to macrolide antibiotics’ were the major contributor of resistance with a prevalence of 39.7%, followed by ‘16s rRNA with mutation conferring resistance to aminoglycoside antibiotics’- 22.2%, ‘16S rRNA with mutation conferring resistance to tetracycline derivatives’- 9.2%, and ‘23S rRNA with mutation conferring resistance to lincosamide antibiotics’- 6.7%. The most prevalent antimicrobial resistance gene (ARG) ‘mutations in the 23S rRNA gene conferring resistance to macrolide antibiotics’ was present in multiple pathogens including Escherichia coli, Campylobacter jejuni, Acinetobacter baumannii, Streptococcus pneumoniae, Pseudomonas aeruginosa, Neisseria gonorrhoeae, Klebsiella pneumoniae and Helicobacter pylori. Most of the geographical locations in the city showed a similar landscape for AMR. Considering human mobility and anthropogenic activities, such an AMR landscape could be common across other regions too. The data indicates that pathogens are evolving and acquiring antibiotic resistance genes to evade antibiotics of multiple major drug classes in diverse hosts. The outcomes of the study are relevant not only in understanding the resistance landscape at a broader level but are also important for identifying the resistant drug classes, the mechanisms of gaining resistance and for developing new drugs that target specific pathways. This kind of surveillance protocol can be extended to regions in other developing countries to assess and combat the problem of antimicrobial resistance.

Mapping the widespread distribution and transmission dynamics of linezolid resistance in humans, animals, and the environment

BackgroundThe rise of linezolid resistance has been widely observed both in clinical and non-clinical settings. However, there were still data gaps regarding the comprehensive prevalence and interconnections of linezolid resistance genes across various niches.ResultsWe screened for potential linezolid resistance gene reservoirs in the intestines of both humans and animals, in meat samples, as well as in water sources. A total of 796 bacteria strains out of 1538 non-duplicated samples were identified to be positive for at least one linezolid resistance gene, optrA, poxtA, cfr, and cfr(D). The prevalence of optrA reached 100% (95% CI 96.3–100%) in the intestines of pigs, followed by fish, ducks, and chicken at 77.5% (95% CI 67.2–85.3%), 62.0% (95% CI 52.2–70.9%), and 61.0% (95% CI 51.2–70.0%), respectively. The meat and water samples presented prevalences of 80.0% (95% CI 70.6–87.0%) and 38.0% (95% CI 25.9–51.9%), respectively. The unreported prevalence of the cfr(D) gene was also relatively higher at 13.0% (95% CI 7.8–21.0%) and 19.0% (95% CI 10.9–25.6%) for the feces samples of ducks and pigs, respectively. Enterococci were the predominant hosts for all genes, while several non-enterococcal species were also identified. Phylogenetic analysis revealed a significant genetic distance among linezolid resistance gene reservoirs, with polyclonal structures observed in strains within the same niche. Similar genetic arrays harboring assorted insertion sequences or transposons were shared by reservoirs displaying heterogeneous backgrounds, though large diversity in the genetic environment of linezolid resistance genes was also observed.ConclusionsThe linezolid resistance genes were widespread among various niches. The horizontal transfer played a crucial role in driving the circulation of linezolid resistance reservoirs at the human-animal-environment interfaces.96S1xiBHwsMdUXcKCqEsW5Video

Phenotypic, molecular detection, and Antibiotic Resistance Profile (MDR and XDR) of Aeromonas hydrophila isolated from Farmed Tilapia zillii and Mugil cephalus

In the present study, Aeromonas hydrophila was isolated from Tilapia zillii and Mugil cephalus samples collected during different seasons from various Suez Canal areas in Egypt. The prevalence of A. hydrophila, virulence genes, and antibiotic resistance profile of the isolates to the commonly used antibiotics in aquaculture were investigated to identify multiple drug resistance (MDR) and extensive drug-resistant (XDR) strains. In addition, a pathogenicity test was conducted using A. hydrophila, which was isolated and selected based on the prevalence of virulence and resistance genes, and morbidity of natural infected fish. The results revealed that A. hydrophila was isolated from 38 of the 120 collected fish samples (31.6%) and confirmed phenotypically and biochemically. Several virulence genes were detected in retrieved A. hydrophila isolates, including aerolysin aerA (57.9%), ser (28.9%), alt (26.3%), ast (13.1%), act (7.9%), hlyA (7.9%), and nuc (18.4%). Detection of antibiotic-resistant genes revealed that all isolates were positive for blapse1 (100%), blaSHV (42.1%), tetA (60.5%), and sul1 (42.1%). 63.1% of recovered isolates were considered MDR, while 28.9% of recovered isolates were considered XDR. Some isolates harbor both virulence and MDR genes; the highest percentage carried 11, followed by isolates harboring 9 virulence and resistance genes. It could be concluded that the high prevalence of A. hydrophila in aquaculture species and their diverse antibiotic resistance and virulence genes suggest the high risk of Aeromonas infection and could have important implications for aquaculture and public health.

Comparison of tet(X4)-containing contigs assembled from metagenomic sequencing data with plasmid sequences of isolates from a cohort of healthy subjects.

Recently discovered tet(X) gene variants have provided new insights into microbial antibiotic resistance mechanisms and their potential consequences for public health. This study focused on detection, analysis, and characterization of Tet(X4)-positive Enterobacterales from the gut microbiota of a healthy cohort of individuals in Singapore using cultivation-dependent and cultivation-independent approaches. Twelve Tet(X4)-positive Enterobacterales strains that were previously obtained from the cohort were fully genome-sequenced and comparatively analyzed. A metagenomic sequencing (MS) data set of the same samples was mined for contigs that harbored the tet(X4) resistance gene. The sequences of tet(X4)-containing contigs and plasmids sequences were compared. The presence of the resistance genes floR and estT (previously annotated as catD) was detected in the same cassette in 10 and 12 out of the 12 tet(X4)-carrying plasmids, respectively. MS detected tet(X4)-containing contigs in 2 out of the 109 subjects, while cultivation-dependent analysis previously reported a prevalence of 10.1%. The tet(X4)-containing sequences assembled from MS data are relatively short (~14 to 33 kb) but show high similarity to the respective plasmid sequences of the isolates. Our findings show that MS can complement efforts in the surveillance of antibiotic resistance genes for clinical samples, while it has a lower sensitivity than a cultivation-based method when the target organism has a low abundance. Further optimization is required if MS is to be utilized in antibiotic resistance surveillance.IMPORTANCEThe global rise in antibiotic resistance makes it necessary to develop and apply new approaches to detect and monitor the prevalence of antibiotic resistance genes in human populations. In this regard, of particular interest are resistances against last-resort antibiotics, such as tigecycline. In this study, we show that metagenomic sequencing can help to detect high abundance of the tigecycline resistance gene tet(X4) in fecal samples from a cohort of healthy human subjects. However, cultivation-based approaches currently remain the most reliable and cost-effective method for detection of antibiotic-resistant bacteria.

Antimicrobial peptides: An alternative to antibiotic for mitigating the risks of Antibiotic resistance in aquaculture

The utilization of antibiotics increases the prevalence of antibiotic resistance genes (ARGs) in various matrices and poses the potential risk of ARG transmission, garnering global attention. Antimicrobial peptides (AMPs) represent a promising novel category of antimicrobials that may address the urgent issue of antibiotic resistance. Here, a zebrafish cultivation assay in which zebrafish were fed a diet supplemented with AMP (Cecropin A) or antibiotics was conducted to determine the effects of the intervention on the microorganisms and antibiotic resistance spectrum in zebrafish gut samples. Cecropin A treatment decreased the α-diversity of the microbiota. Moreover, NMDS (nonmetric multidimensional scaling) results revealed that the β-diversity in the microbiota was more similar between the control (CK) and Cecropin A samples than between the antibiotic treatment groups. The absolute quantity of ARGs in the AMP treatment was less than that observed in the antibiotic treatment. The findings indicated that FFCH7168, Chitinibacter and Cetobacterium were the most significant biomarkers detected in the CK, Cecropin A and antibiotic treatments, respectively. Although the use of antibiotics notably enhanced the occurrence of multidrug-resistant bacteria, the application of Cecropin A did not lead to this phenomenon. The results indicated that the application of AMPs can effectively manage and control ARGs in aquaculture.

Outbreak of colistin and carbapenem-resistant Klebsiella pneumoniae ST16 co-producing NDM-1 and OXA-48 isolates in an Iranian hospital

BackgroundColistin and carbapenem-resistant Klebsiella pneumoniae (Col-CRKP) represent a significant and constantly growing threat to global public health. We report here an outbreak of Col-CRKP infections during the fifth wave of COVID-19 pandemic.MethodsThe outbreak occurred in an intensive care unit with 22 beds at a teaching university hospital, Isfahan, Iran. We collected eight Col-CRKP strains from seven patients and characterized these strains for their antimicrobial susceptibility, determination of hypermucoviscous phenotype, capsular serotyping, molecular detection of virulence and resistance genes. Clonal relatedness of the isolates was performed using MLST.ResultsThe COVID-19 patients were aged 24–75 years with at least 50% pulmonary involvement and were admitted to the intensive care unit. They all had superinfection caused by Col-CRKP, and poor responses to antibiotic treatment and died. With the exception of one isolate that belonged to the ST11, all seven representative Col-CRKP strains belonged to the ST16. Of these eight isolates, one ST16 isolate carried the iucA and ybtS genes was identified as serotype K20 hypervirulent Col-CRKP. The blaSHV and blaNDM-1 genes were the most prevalent resistance genes, followed by blaOXA-48 and blaCTX-M-15 and blaTEM genes. Mobilized colistin-resistance genes were not detected in the isolates.ConclusionsThe continual emergence of ST16 Col-CRKP strains is a major threat to public health worldwide due to multidrug-resistant and highly transmissible characteristics. It seems that the potential dissemination of these clones highlights the importance of appropriate monitoring and strict infection control measures to prevent the spread of resistant bacteria in hospitals.

Gamma-ray irradiation as an effective method for mitigating antibiotic resistant bacteria and antibiotic resistance genes in aquatic environments

The prevalence of antibiotic resistance genes (ARGs) in municipal wastewater treatment plants (MWTPs) has emerged as a significant environmental concern. Despite advanced treatment processes, high levels of ARGs persist in the secondary effluent from MWTPs, posing ongoing environmental risks. This study explores the potential of gamma-ray irradiation as a novel approach for sterilizing antibiotic-resistant bacteria (ARB) and reducing ARGs in MWTP secondary effluent. Our findings reveal that gamma-ray irradiation at an absorbed dose of 1.6 kGy effectively deactivates all culturable bacteria, with no subsequent revival observed after exposure to 6.4 kGy and a 96-h incubation in darkness at room temperature. The removal efficiencies for a range of ARGs, including tetO, tetA, blaTEM-1, sulI, sulII, and tetW, were up to 90.5% with a 25.6 kGy absorbed dose. No resurgence of ARGs was detected after irradiation. Additionally, this study demonstrates a considerable reduction in the abundances of extracellular ARGs, with the transformation efficiencies of extracellular tetracycline and sulfadiazine resistance genes decreasing by 56.3–81.8% after 25.6 kGy irradiation. These results highlight the effectiveness of gamma-ray irradiation as an advanced and promising method for ARB sterilization and ARG reduction in the secondary effluent of MWTPs, offering a potential pathway to mitigate environmental risks associated with antibiotic resistance.

Deciphering soil resistance and virulence gene risks in conventional and organic farming systems

Organic farming is a sustainable agricultural practice emphasizing natural inputs and ecological balance, and has garnered significant attention for its potential health and environmental benefits. However, a comprehensive evaluation of the emergent contaminants, particularly resistance and virulence genes within organic farming system, remains elusive. Here, a total of 36 soil samples from paired conventional and organic vegetable farms were collected from Jiangsu province, China. A systematic metagenomic approach was employed to investigate the prevalence, dispersal capability, pathogenic potential, and drivers of resistance and virulence genes across both organic and conventional systems. Our findings revealed a higher abundance of antibiotic resistance genes (ARGs), biocide resistance genes (BRGs), and virulence factor genes (VFGs) in organic farming system, with ARGs exhibiting a particularly notable increase of 10.76% compared to the conventional one. Pathogens such as Pseudomonas aeruginosa, Escherichia coli, and Mycobacterium tuberculosis were hosts carrying all four gene categories, highlighting their potential health implications. The neutral community model captured 77.1% and 71.9% of the variance in community dynamics within the conventional and organic farming systems, respectively, indicating that stochastic process was the predominant factor shaping gene communities. The relative smaller m value calculated in organic farming system (0.021 vs 0.023) indicated diminished gene exchange with external sources. Moreover, farming practices were observed to influence the resistance and virulence gene landscape by modifying soil properties, managing heavy metal stress, and steering mobile genetic elements (MGEs) dynamics. The study offers insights that can guide agricultural strategies to address potential health and ecological concerns.

The impact of polymorphic variants of interferon receptor genes on COVID-19 severity and antibiotic resistance

Single nucleotide substitutions in gene sequence associated with conformational changes in protein receptor or in expression of interferon receptors may explain variations in human susceptibility to infection and severity of COVID-19 along with other well-known risk factors. The study aimed to investigate associations between polymorphic variants of interferon receptor genes, COVID-19 severity and prevalence of antibiotic resistance genes in the gut microbiota. Materials and methods. The study was conducted using a random sample of Arkhangelsk population aged 42 to 76 years (n = 305). The research involved gathering COVID-19 data from the Federal Register, conducting blood tests for SARS-CoV-2 antibodies and polymorphic interferon receptor gene variants, and identifying antibiotic resistance genes in stool samples. Results. During the first 12–15 months of the COVID-19 pandemic, 17.4% of the study participants had symptomatic COVID-19, while 32.8% were asymptomatic. By the Autumn of 2022, symptomatic COVID-19 cases rose up to 36.4%, while asymptomatic cases increased to 61.3%. We reveal an association between the CC genotype of the IFNAR1 gene rs2257167 variant, the presence of the T allele of IFNAR2 gene rs2229207 variant, the CCTT haplotype and symptomatic COVID-19. The GCTC haplotype was associated with pneumonia and COVID-19 severity. In November 2022, macrolide resistance genes were observed in 98.4% of cases, whereas those to beta-lactams and glycopeptides — in 26.9% and 13.8% cases, respectively. Resistance to three classes of antibiotics was observed in 4.9% and was more frequently detected in individuals with the ССТТ haplotype. Genes encoding beta-lactamases were more often found in individuals with the GCTC haplotype, those who had COVID-19 with pneumonia and those who received hospital treatment. Glycopeptide resistance genes were associated with the CC genotype of the rs2257167 variant of IFNAR1 gene. Conclusion. We identified genetic determinants of susceptibility, symptomatic infection and COVID-19 severity. The associations between polymorphic variants of interferon receptor genes and COVID-19 severity can be used to identify people with a genetic predisposition to severe infection and to determine priority groups for vaccination, including the prevention of antibiotic resistance in complicated course of viral infections.

The prevalence of antibiotic resistance genes of carbopenemases of the metallo-β-lactamase group in enterobacteria strains isolated from patients of a multidisciplinary hospital in a region with a developed petrochemical industry

The research work included strains of Klebsiella pneumonaie (n = 128) isolated from patients of a multidisciplinary hospital in a large industrial city. The antibiotic sensitivity of the isolated pure cultures was studied in relation to the most popular antibacterial drugs in clinical practice (in the amount of 21), by the standard disco-diffusion method. Identification of resistance genes was carried out by PCR using commercial reagent kits «AmpliSens MDR-MBL-FL», «AmpliSens MDR-KPC/OXA-48‑FL». The results of determining the sensitivity of isolates isolated from the lower respiratory tract revealed low activity of amoxicillin/clavulanic acid, cephalosparins of the III and IV generation (ceftazidim, cefotaxime, cefepim). 86.7 % of isolates are resistant to the aminoglycoside group — amikacin, and 100 % are resistant to gentamicin. Meropenem was the most active of the carbapenem group — 26.6 %, about 7 % are sensitive to ertapenem. From the group of fluoroquinolones, the sensitivity varied from 20 to 30 %. The greatest activity of all drugs was shown by ticarcillin / clavulanate — 33.3 %. A high proportion of strains of Kl. pneumoniae with a phenotype of multiple resistance has been established. The identification of resistance genes made it possible to establish their diversity in antibiotic-resistant isolates, a high proportion (26.6 %) of multi-resistant strains with the absence of the studied genes, and the combination of VIM + NDM + OXA-48 genes, identified in every second studied strain, prevails. Thus, the analysis of the prevalence of antibiotic resistance genes of carbopenemases of the metallo- β-lactamase group in enterobacteria strains isolated from patients of a multidisciplinary hospital in a region with a developed petrochemical industry showed the predominance of isolates (53.9 %) with the production of a combination of three antibiotic resistance genes (VIM + NDM + OXA-48). Isolates containing two genes simultaneously (NDM + OXA-48 and VIM + OXA-48) identified in 7.8 and 6.3 %. Isolates containing a single gene (carbapenemase Kl. Pneumoniae) amounted to 5.4 %.

Epidemiological investigation and β-lactam antibiotic resistance of Riemerella anatipestifer isolates with waterfowl origination in Anhui Province, China

Riemerella anatipestifer (R. anatipestifer) is a highly pathogenic and complex serotypes waterfowl pathogen with inherent resistance to multiple antibiotics. This study was aimed to investigate the antibiotic resistance characteristics and genomic features of R. anatipestifer isolates in Anhui Province, China in 2023. A total of 287 cases were analysed from duck farms and goose farms, and the R. anatipestifer isolates were subjected to drug resistance tests for 30 antimicrobials. Whole genome sequencing (WGS) and bioinformatics analysis were performed on the bacterial genomes, targeting the β-lactam resistance genes. The results showed that a total of 74 isolates of R. anatipestifer were isolated from 287 cases, with a prevalence of 25.8%. The antimicrobial susceptibility testing (AST) revealed that all the 74 isolates were resistant to multiple drugs, ranging from 13 to 26 kinds of drugs. Notably, these isolates showed significant resistance to aminoglycosides and macrolides, which are also commonly used in clinical practices. Data revealed the presence of several β-lactamase-related genes among the isolates, including a novel blaRASA-1 variant (16.2%), the class A extended-spectrum β-lactamase blaRAA-1 (12.2%), and a blaOXA-209 variant (98.6%). Functional analysis of the variants blaRASA-1 and blaOXA-209 showed that the blaRASA-1 variant exhibited activity against various β-lactam antibiotics while their occurrence in R. anatipestifer were not common. The blaOXA-209 variant, on the other hand, did not perform any β-lactam antibiotic resistance. Furthermore, we observed that blaRAA-1 could undergo horizontal transmission among different bacteria via the insertion sequence IS982. In conclusion, this study delves into the high prevalence of R. anatipestifer infection in waterfowl in Anhui, China. The isolated strains exhibit severe drug resistance issues, closely associated with the prevalence of antibiotic resistance genes (ARG). Additionally, our research investigates the β-lactam antibiotic resistance mechanism in R. anatipestifer.

Linezolid Resistance Genes and Mutations among Linezolid-Susceptible Enterococcus spp.-A Loose Cannon?

The National Reference Centre for Enterococci receives an increasing number of linezolid-resistant Enterococcus isolates. Linezolid (LIN) resistance is mediated by G2576T 23S rDNA gene mutations and/or acquisition of resistance genes (cfr, optrA, poxtA). There are anecdotal reports that those resistance traits may be present in phenotypically linezolid-susceptible isolates. We aimed to determine the prevalence of LIN resistance genes and mutations in enterococci with a LIN MIC of 4 mg/L in broth microdilution (EUCAST = susceptible) isolated from German hospital patients 2019-2021. LIN MICs were additionally determined by ETEST® and VITEK2. Selected strains were subjected to LIN selective pressure and growth was monitored with increasing antibiotic concentrations. We received 195 isolates (LIN MIC = 4 mg/L). In total, 78/195 (40%) isolates contained either a putative resistance gene, the G2576T mutation, or a combination thereof. Very major error was high for broth microdilution. The ability to predict phenotypic resistance from genotypic profile was highest for G2576T-mediated resistance. Selection experiments revealed that, in particular, E. faecium isolates with resistance gene mutations or poxtA rapidly adapt to MICs above the clinical breakpoint. In conclusion, LIN resistance genes and mutations can be observed in phenotypically linezolid-susceptible enterococci. Those isolates may rapidly develop resistance under LIN selective pressure potentially leading to treatment failure.

A longitudinal epidemiology study of fluoroquinolone-nonsusceptible Klebsiella pneumoniae reveals an increasing prevalence of qnrB and qnrS in Taiwan

BackgroundOur objective was to investigate the prevalence of plasmid-mediated quinolone resistance (PMQR) genes in fluoroquinolone-nonsusceptible Klebsiella pneumoniae (FQNSKP) in Taiwan, 1999–2022. MethodsA total of 938 FQNSKP isolates were identified from 1966 isolates. The presence of PMQR and virulence genes, antimicrobial susceptibility, capsular types, and PMQR-plasmid transferability were determined. ResultsAn increasing number of PMQR-containing FQNSKP isolates were observed over the study period. Our results showed that 69.0% (647 isolates) of FQNSKP isolates contained at least one PMQR gene, and 40.6%, 37.0%, and 33.9% of FQNSKP carried aac(6′)-Ib-cr, qnrB, and qnrS, respectively. None of FQNSKP carried qepA and qnrC. The most common combination of PMQR genes was aac(6′)-Ib-cr and qnrB (12.3%). The presence of PMQR genes is strongly related to resistance to aminoglycoside, cephalosporin, tetracycline, and sulfamethoxazole/trimethoprim in FQNSKP. The capsular serotype K64 is the most common serotype we tested in both the non-PMQR and PMQR FQNSKP isolates, while K20 showed a higher prevalence in PMQR isolates. The magA and peg-344 genes showed a significantly higher prevalence rate in non-PMQR isolates than in PMQR isolates. Eleven isolates that carried the PMQR and carbapenemase genes were identified; however, three successful transconjugants showed that the PMQR and carbapenemase genes were not located on the same plasmid. ConclusionsOur results indicated an increasing prevalence of PMQR genes, especially qnrB and qnrS, in FQNSKP in Taiwan. Moreover, the distribution of PMQR genes was associated with capsular serotypes and antimicrobial resistance gene and virulence gene distribution in FQNSKP.