Carrying Resistance Genes Research Articles

Emergence of Multidrug-Resistant NDM-5-Producing ST307 Klebsiella pneumoniae in Uruguay, 2023.

Carbapenem and colistin-resistant Klebsiella pneumoniae pose a significant threat to public health, particularly in intensive care units, due to high morbidity and mortality rates. This study aimed to analyze five NDM carbapenemase-producing multidrug-resistant K. pneumoniae isolates from different hospitals. Antimicrobial susceptibility testing, hypermucoviscosity analysis, biofilm production assessment, MLST, PCR, and whole-genome sequencing were conducted. All isolates harbored NDM-5 metallo-β-lactamase, belonging to MLST 307, were biofilm producers and exhibited a stop codon (Q30) along MgrB. Genomic analysis revealed multiple-replicon plasmids carrying resistance genes, notably blaNDM-5, blaCTX-M-15, rmtB, and qnrB1, with complex genetic structures encoding several mobile genetic elements, including the Tn3 family and IS26. All isolates harbored wzi173 (capsule-locus KL102), iutA (a siderophore-associated gene), and the type 3 fimbriae mrkABCDFHIJ operon. The core genome single nucleotide polymorphisms (SNPs) analysis suggests the circulation of two strains of ST307 clone (SNPs range differences 4-77). These findings highlight the potential plasticity of the high-risk ST307 clone and the urgent need for surveillance and intervention strategies to combat antimicrobial resistance. To our knowledge, this is the first report of K. pneumoniae ST307 carrying blaNDM-5 and the first description of ST307 in Uruguay. The presence of blaNDM-5 and pan-aminoglycoside resistance rmtB genes are identified for the first time in Uruguay.

Genome drafting of nosocomial infection CRE Klebsiella pneumoniae confirming resistance to colistin and eravacycline, carrying blaNDM-1, mcr-1, and blaKPC-2, in neonatology from November to December 2023

BackgroundCarbapenem-resistant Klebsiella pneumoniae (CRKP) is a critical pathogen in healthcare settings, associated with high mortality due to its extensive antibiotic resistance. In this study, we report an outbreak of CRKP in a neonatal intensive care unit (NICU) within a 200-bed tertiary hospital. The main goal of this study was to characterize the phenotypic and genomic profiles of the CRKP isolates involved in the outbreak and to gain insights into their resistance mechanisms and transmission dynamics within the NICU.MethodsThe study was conducted between November and December 2023 in a 5-bed NICU. Monthly surveillance cultures were performed to monitor colonization and infection with multidrug-resistant organisms. CRKP isolates were obtained from blood and nasal swabs of affected neonates. Identification and antimicrobial susceptibility testing were initially conducted using the Vitek®2 system with an N-395 card and further confirmed by 16S rRNA sequencing. Whole-genome sequencing (WGS) and antimicrobial resistance (AMR) profiling were performed to identify resistance genes and virulence factors. For genetic analysis, both Illumina short-read and Nanopore long-read sequencing were used, followed by hybrid assembly for enhanced genome resolution. Plasmid and resistance gene profiles were determined using AMRFinder and PlasmidFinder databases.ResultsA total of three CRKP isolates (designated Kp1, Kp2, and Kp3) were identified. Kp1 and Kp2 belonged to sequence type (ST) ST23 and were genetically near-identical, differing by a single allele, while Kp3 was of a distinct sequence type, ST2096, with 245 allelic differences from Kp1 and Kp2. All isolates were resistant to colistin and carried resistance genes, including mcr-1 and blaNDM-1,blaKPC2 confirming carbapenem resistance. Efflux pump genes and aminoglycoside resistance genes were also detected, providing a multifaceted defence against antibiotics. Plasmid analysis identified several incompatibility groups (IncFI, IncHI, IncFIB, IncX), indicating the potential for horizontal gene transfer of resistance determinants.ConclusionThis study highlights the complexity of CRKP outbreaks in neonatal care, with isolates exhibiting resistance mechanisms that complicate treatment. The plasmid profiles suggest these strains are reservoirs for multidrug-resistant genes, emphasizing the need for strict infection control and ongoing genomic surveillance. For neonatal care, these resistance challenges increase the risk of treatment failures and mortality, underscoring the importance of enhanced infection prevention and novel therapeutic strategies.

Prevalence and Risk Factors for Colonization with Carbapenem-Resistant Microorganisms in Patients Admitted to a Multidisciplinary Hospital

Relevance. In the last decade, there has been an increase in the isolation of antibiotic-resistant microorganisms in community settings. Colonization and asymptomatic carriage of extended-spectrum beta-lactamase and carbapenemase producers can be a precursor to the development of an infectious process and a significant factor in the pathogenesis of healthcare-associated infections. Understanding the risk factors for community-acquired colonization with antibiotic-resistant microorganisms is necessary for targeted screening and timely implementation of measures to prevent the spread of resistance in hospitals.The aim. To determine significant risk factors for colonization with antibiotic-resistant gram-negative microorganisms and carriage of carbapenem resistance genes in patients admitted to a multidisciplinary hospital.Materials & Methods. A prospective single-center crosssectional study was conducted at the Moscow Multidisciplinary Clinical Center «Kommunarka» from 15.09.2022 to 15.08.2023. The study included 733 patients aged 18 to 94 years. Biological samples were taken from the rectum, upper and lower respiratory tract. The obtained samples were examined by real-time polymerase chain reaction (PCR) with hybridization-fluorescent detection of amplification products to identify carbapenemase genes and by culture method to determine colonization with carbapenemresistant bacteria. Identification of isolated microorganisms was performed using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), and antibiotic susceptibility was determined by the Kirby-Bauer disk diffusion method on Mueller-Hinton agar. The results of susceptibility testing were interpreted based on EUCAST v12.0, v13.0, and v13.1 criteria.Results. Carriage of carbapenemase genes was detected in 12.6% of patients admitted to the hospital, while colonization with carbapenem-resistant bacteria was found in 2.7%. In the majority of patients (66.7%), the rectum was the only site of gene carriage. However, only 18.1% of these patients showed rectal colonization with carbapenem-resistant bacteria. This discrepancy is likely due to the higher sensitivity of molecular genetic methods compared to culture-based techniques. From a clinical perspective, the detection of nucleic acids by PCR can serve as an equivalent to pathogen detection in biological material. Multivariate analysis identified 5 independent predictors of colonization: cytostatic therapy, transfer from another hospital, need for vasopressor support, antibiotic use in the previous 3 months, and male gender.Conclusion. The identified risk factors allow for the identification of a highrisk patient cohort for targeted screening, enabling timely administration of appropriate antibiotic therapy and implementation of measures to prevent the spread of carbapenem resistance in the hospital.

Prevalence of Uropathogenic E. Coli, Antimicrobial Susceptibility Profiles and Carriage of Extended-Spectrum Beta-Lactamases Genes at Mama Lucy Hospital, Kenya

Purpose: Urinary tract infection (UTI) is a common bacterial infection affecting millions worldwide. Escherichia coli (E. coli) is the most prevalent causative agent of UTIs. This study aimed to determine the prevalence, antimicrobial susceptibility profiles and carriage of ESβL resistance genes among uropathogenic E. coli recovered from adults at Mama Lucy Hospital. Methodology: A cross-sectional study was conducted. A purposive method was used to obtain 347 urine samples from patients who presented with symptoms suggestive of UTI and were cultured for E. coli using cysteine lactose electrolyte-deficient agar and eosin methylene blue agar. The collected urine samples were also subjected to dipstick analysis and microscopy. Questionnaires were used to collect sociodemographic data and possible risk factors for urinary tract infections. The recovered isolates were identified using conventional biochemical tests. Antimicrobial susceptibility profiles were determined using the Kirby diffusion disc method. The occurrence of ESβLs, including TEM, OXA, SHV, and CTX-M, was determined by polymerase chain reaction (PCR). Findings: The overall prevalence rate of UTIs was 23.7%, whereas the E. coli prevalence rate was 13.3%. The isolates presented high levels of resistance to trimethoprim-sulfamethoxazole (81.3%), amoxicillin-clavulanic acid (66.7%), ciprofloxacin (62.5%), tetracycline (60.4%), ceftriaxone (54.2%), and cefoxitin (54.2%), whereas they were more susceptible to meropenem (14.6%), chloramphenicol (12.5%), and nitrofurantoin (8.3%). A total of 25 of the 46 E. coli isolates were screened for ESβL genes. TEM was the most common gene21/25 (84%), SHV12/25 (48%), OXA 7/25 (28%), and CTX-M 18/25 (66.1%), which indicates a high frequency of β-lactamase gene production among UTIs causing E. coli. Unique Contribution to Theory, Practice and Policy: Based on these findings, current treatment guidelines should be revised to prevent increasing antimicrobial resistance through continuous surveillance, screening for extended-spectrum beta-lactamase genes, routine culture and antibiotic sensitivity testing. Additionally, the prevalence of UTIs should be continuously monitored to monitor trends that form a basis for preventive and treatment guidelines, such as policy development and prudent use of antibiotics, to reduce the increasing UTI burden in the population.

Antibiotic exposure enriches streptococci carrying resistance genes in periodontitis plaque biofilms.

Periodontitis is not always satisfactorily treated with conventional scaling and root planing, and adjunctive use of antibiotics is required in clinical practice. Therefore, it is important for clinicians to understand the diversity and the antibiotic resistance of subgingival microbiota when exposed to different antibiotics. In this study, subgingival plaques were collected from 10 periodontitis patients and 11 periodontally healthy volunteers, and their microbiota response to selective pressure of four antibiotics (amoxicillin, metronidazole, clindamycin, and tetracycline) were evaluated through 16S rRNA gene amplicon and metagenomic sequencing analysis. Additionally, sensitive and resistant strains were isolated and cultured in vitro for resistance evaluation. Cultivation of subgingival microbiota revealed the oral microbiota from periodontitis patients were more resistant to antibiotics than that of healthy. Significant differences were also observed for the microbial community between with and without antibiotics (especially amoxicillin and tetracycline) treated in periodontitis group. Overall, after the two antibiotics (amoxicillin and tetracycline) exposed, the oral subgingival microbiota in periodontitis patients exhibited different diversity and composition. Streptococcus may account for oral biofilm-specific antibiotic resistance in periodontitis. This provides information for personalized treatment of periodontitis.

An Epidemiological Study on Salmonella in Tibetan Yaks from the Qinghai-Tibet Plateau Area in China.

Salmonella is an important foodborne pathogen that can cause a range of illnesses in humans; it has also been a key focus for monitoring in the field of public health, including gastroenteritis, sepsis, and arthritis, and can also cause a decline in egg production in poultry and diarrhea and abortion in livestock, leading to death in severe cases, resulting in huge economic losses. This study aimed to investigate the isolation rate, antimicrobial resistance, serotypes, and genetic diversity of Salmonella isolated from yak feces in various regions on the Qinghai-Tibet Plateau. A total of 1222 samples of yak dung were collected from major cities in the Qinghai-Tibet Plateau area, and the sensitivity of the isolated bacteria to 10 major classes of antibiotics was determined using the K-B paper disk diffusion method for drug susceptibility. Meanwhile, the serotypes of the isolated bacteria were analyzed using the plate agglutination test for serum antigens, and their carriage of drug resistance and virulence genes was determined using PCR and gel electrophoresis experiments. The isolated bacteria were also classified using MLST (Multi-Locus Sequence Typing). The overall isolation rate for Salmonella was 18.25% (223/1222), and the results of the antibiotic susceptibility tests showed that 98.65% (220/223) of the isolated bacteria were resistant to multiple antibiotics. In the 223 isolates of Salmonella, eight classes of 20 different resistance genes, 30 serotypes, and 15 different types of virulence genes were detected. The MLST analysis identified 45 distinct sequence types (STs), including five clonal complexes, of which ST34, ST11, and ST19 were the most common. These findings contribute valuable information about strain resources, genetic profiles, and typing data for Salmonella in the Qinghai-Tibet Plateau area, facilitating improved bacterial surveillance, identification, and control in yak populations. They also provide certain data supplements for animal Salmonella infections globally, filling research gaps.

Acinetobacter baumannii Co-Resistant to Extended Spectrum Beta-Lactamases and Carbapenemases in Six Peruvian Hospital Centers

Objectives: The aim of this study was to describe the phenotypic and molecular characteristics of Acinetobacter baumannii isolates carrying resistance genes to beta-lactams and carbapenems in six Peruvian public hospital centers. Materials and methods: The susceptibility of bacterial isolates was determined using the automated MicroScan system, with interpretation according to the M100 S30 CLSI 2020. Resistance genes were identified by conventional polymerase chain reaction (PCR), and PCR products were visualized by 1% agarose gel electrophoresis. Results: Nine strains (TRU1, PM1, PM2, CUS1, CUS2, CUS3, CAL1, CAL2 and CAL3) out of a total of 21 strains in the study were reactivated, showing resistance of 77.8% to imipenem, ciprofloxacin and cefepime, followed by 66.7% resistance to meropenem and ceftazidime, indicating marked multidrug resistance. In addition, the detection of the group A beta-lactamase genes blaCTX-M and blaTEM was confirmed, showing co-resistance in strains CUS1, CUS2 and CUS3, despite their unusual presence in this pathogen, also determined by the presence of the group D carbapenemase blaOXA in strain CUS3, the only strain to show co-resistance of the three groups. Conclusion: The prevalence of Acinetobacter baumannii resistant to extended-spectrum beta-lactamases and carbapenemases in Peruvian public centers represents a critical challenge for the treatment of infections. Rigorous surveillance, infection control strategies, and the development of alternative therapies are urgently needed to address this growing bacterial resistance.

The association between the genetic structures of commonly incompatible plasmids in Gram-negative bacteria, their distribution and the resistance genes.

Incompatible plasmids play a crucial role in the horizontal transfer of antibiotic resistance in bacteria, particularly in Gram-negative bacteria, and have thus attracted considerable attention in the field of microbiological research. In the 1970s, these plasmids, housing an array of resistance genes and genetic elements, were predominantly discovered. They exhibit a broad presence in diverse host bacteria, showcasing diversity in geographic distribution and the spectrum of antibiotic resistance genes. The complex genetic structure of plasmids further accelerates the accumulation of resistance genes in Gram-negative bacteria. This article offers a comprehensive review encompassing the discovery process, host distribution, geographic prevalence, carried resistance genes, and the genetic structure of different types incompatible plasmids, including IncA, IncC, IncF, IncL, IncM, IncH, and IncP. It serves as a valuable reference for enhancing our understanding of the role of these different types of plasmids in bacterial evolution and the dissemination of antibiotic resistance.

A ‘Tuba Drain’ incorporated in sink drains reduces counts of antibiotic-resistant bacterial species at the plughole: a blinded, randomized trial in 36 sinks in a hospital outpatient department with a low prevalence of sink colonization by antibiotic-resistant species

Multi-resistant Gram-negative bacteria (GNB) survive in hospital drains in traps that contain water and may ascend into the sink because of splashes, or biofilm growth. To investigate whether the 'Tuba Drain' (TD) a long, bent, continually descending copper tube between the sink outlet and the trap prevents the ascent of bacteria. After initial laboratory tests confirmed that the TD prevented bacteria in the U-bend from splashing upwards into the sink outlet, TDs were assessed in a randomized, blinded trial in a hospital outpatient department built in 2019. Sinks were paired into those with a similar clinical exposure and each member of each pair was randomized to receive either new, standard plumbing up to and including the trap (18 sinks) or the same new standard plumbing but including the TD inserted between the sink outlet and trap. Bacterial counts in swabs from the sink outlets were determined blindly before and monthly after the plumbing change for a year. GNB that are associated with clinical infection and carriage of resistance genes, Pseudomonas aeruginosa, Acinetobacter baumanii, Stenotrophomonas maltophilia and all Enterobacterales were the organisms of primary interest and termed target bacteria. The TDs fitted into the required spaces and functioned without problems. The geometric means (over months) of the counts of target bacteria in TD-plumbed sinks was lower than those in their paired controls, P=0.012 (sign test, two-tailed). Prevalence of target bacteria in sinks was low. TDs were effective for reducing target bacteria in sinks.

Longitudinal genomic surveillance of a UK intensive care unit shows a lack of patient colonisation by multi-drug-resistant Gram-negative bacterial pathogens.

Vulnerable patients in an intensive care unit (ICU) setting are at high risk of infection from bacteria including gut-colonising Escherichia coli and Klebsiella species. Complex ICU procedures often depend on successful antimicrobial treatment, underscoring the importance of understanding the extent of patient colonisation by multi-drug-resistant organisms (MDROs) in large UK ICUs. Previous work on ICUs globally uncovered high rates of colonisation by transmission of MDROs, but the situation in UK ICUs is less understood. Here, we investigated the diversity and antibiotic resistance gene (ARG) carriage of bacteria present in one of the largest UK ICUs at the Queen Elizabeth Hospital Birmingham (QEHB), focusing primarily on E. coli as both a widespread commensal and a globally disseminated multi-drug-resistant pathogen. Samples were taken during highly restrictive coronavirus disease 2019 (COVID-19) control measures from May to December 2021. Whole-genome and metagenomic sequencing were used to detect and report strain-level colonisation of patients, focusing on E. coli sequence types (STs), their colonisation dynamics and antimicrobial resistance gene carriage. We found a lack of multi-drug resistance (MDR) in the QEHB. Only one carbapenemase-producing organism was isolated, a Citrobacter carrying bla KPC-2. There was no evidence supporting the spread of this strain, and there was little evidence overall of nosocomial acquisition or circulation of colonising E. coli. Whilst 22 different E. coli STs were identified, only 1 strain of the pandemic ST131 lineage was isolated. This ST131 strain was non-MDR and was found to be a clade A strain, associated with low levels of antibiotic resistance. Overall, the QEHB ICU had very low levels of pandemic or MDR strains, a result that may be influenced in part by the strict COVID-19 control measures in place at the time. Employing some of these infection prevention and control measures where reasonable in all ICUs might therefore assist in maintaining low levels of nosocomial MDR.

Whole-genome sequencing of clinical isolates of Klebsiella michiganensi in China carrying blaIPM-4 and blaNDM-1

AimThis study aimed to analyze the prevalence, phenotypes, and carriage of resistance genes of carbapenem-resistant Klebsiella michiganensis strains isolated in our hospital. Methodology: Four K. michiganensis strains were collected from January 2015 to December 2023. Antimicrobial susceptibility was tested using 21 antibiotics with the BD Phoenix™ M50 System. Whole-genome sequencing of the four strains was performed on an Illumina NovaSeq 6000 platform. Species identification was performed using Kleborate software, sequence type (ST) was performed using MLST, and prediction of antibiotic resistance genes and virulence genes were performed using ABRicate. PlasmidFinder was used to search for plasmids. Whole genome data from 211 strains of carbapenem-resistant K. michiganensis were downloaded from the NCBI database; together with the strains in this study, these data were used to construct an phylogenetic tree using genome single nucleotide polymorphisms (SNP). ResultsAntimicrobial susceptibility showed that K. michiganensis was highly resistant to β-lactams. For the three carbapenems, strain WF0046 was only resistant to ertapenem, while WF0047, WF0052, and WF0053 were resistant to all three carbapenems tested. The four strains of K. michiganensis only showed complete sensitivity to polymyxin E and tigecycline. The four K. michiganensis strains were found to have 43 resistance genes, and all carried carbapenem resistance genes; WF0046 carried the carbapenem resistance gene blaIMP-4, while the other three strains carried blaNDM-1. Among the other resistance genes, β-lactam resistance genes were predicted most (11 types), followed by eight types of aminoglycoside resistance genes. Of the strains characterized in this study, WF0046 belonged to ST158, WF0047 belonged to ST40, WF0052 belonged to ST533, and WF0053 belonged to ST13. These four strains, along with 211 carbapenem-resistant K. michiganensis strains downloaded from NCBI, were divided into five clades; WF0052 belonged to clade A, WF0046 belonged to clade C, and WF0047 and WF0053 both belonged to clade D. The four strains had relatively distant genetic relationships; WF0046, WF0047, and WF0053 were closely related to strains of human origin from other regions of China, while WF0052 was genetically close with a strain of K. michiganensis isolated in the United States. ConclusionThe strains of K. michiganensis from our hospital were resistant to multiple antibiotics, and all strains carried carbapenem resistance genes along with multiple other antibiotic resistance genes. The phylogenetic results showed that these four strains had distant genetic relationships and different ST types, indicating that they came from different sources and the possibility of polyclonal transmission.

Antimicrobial Resistance Gene Carriage is not Associated with Uremic Toxin Levels in Chronic Kidney Disease Patients

In chronic kidney disease (CKD), uremic toxin molecules build up and risk of infection increase overtime, making the presence of antimicrobial resistant (AMR) bacteria in the gut more problematic with advancing disease. This study assessed if serum levels of uremic toxins and gut carriage of AMR genes are correlated in individuals with CKD. Whole metagenomic sequencing of stool samples and measured levels of 4 uremic toxins from 21 individuals with CKD were obtained. Multivariable, multivariate linear regression was performed with total abundance of AMR genes and abundance of specific drug classes of AMR genes as outcome variables and serum levels of four uremic toxins as predictor variables. Beta diversity differences of AMR genes were visualized using non-metric multidimensional scaling (NMDS) based on robust Aitchison distances and tested using PERMANOVA. There were no significant associations between uremic toxin levels and AMR gene abundance, or with any of the drug classes of AMR genes. There were no significant differences in beta diversity of AMR genes. These null findings suggest that increased uremic toxin levels are not associated with an increase in AMR carriage, and therefore uremia does not appear to be a direct cause of increased resistant bacteria in patients with more severe CKD.

A rapid and reliable method for early Legionella pneumophila identification and characterization in support of the epidemiology study.

Legionnaires' disease is a severe pneumonia predominantly caused by Legionella pneumophila (Lp), whose major reservoirs are artificial water systems. As most human infections are caused by L. pneumophila serogroup 1 (Lp1), a reliable method for Lp distinction can be crucial for bacterial spread prevention. As the ability to withstand in environments and to cause the waterborne disease is strongly related to specific genes, the identification of virulent strains can be of great relevance to implement water environmental monitoring and to contain harmful outbreaks to public health. We aimed to test an assay for Lp identification among different Legionella species, and to determine the serogroups. Additionally, we investigated the carriage of virulence and antimicrobial resistance genes. A total of 90 Legionella spp. isolates identified by phenotypic tests were subjected to the designed quantitative PCR assay targeting specific mip for Lp, wzm for Lp1, pvcA and ahpD for biofilm production. Eleven serogroups were investigated in all our isolates tested positive for mip gene, subsequently analyzed for 12 virulence and 8 antimicrobial resistance genes. Only the 70 Lp isolates were positive for mip. Out of 27 Lp isolates belonging to serogroup 1 based on agglutination test, 23 (85.2%) carried wzm. The presence of ahpD and pvcA was found in 94.3 and 98.6% of Lp isolates, respectively. By multiplex PCR, all 23 wzm-positive strains were confirmed as serogroup 1 that was the most predominant (33%). At least one virulence gene was detected in all Lp isolates. The most frequent gene was ispE (100%), followed by issD (96%), icmK and enhC (93%), cpxA (91%), rtxA2 (74%), lvhB8-B9 (61%), and prpA (54%). The other genes were less diffused in Lp strains (rtxA1, 44%; lvhB3-B4, 47%; pvcB, 27%; lvrE, 24%). Of the macrolide resistance genes, the ereA was found in 84% of Lp strains, while only 14 (20%) harbored the lpeAB among the efflux pump genes. The assays validated in this study enable the simultaneous Lp and Lp1 detection. The differentiation of Lp strains according to their virulence properties could be useful to predict the bacterial ability to survive and to cause the disease.

Development of pyramided mung bean lines carrying resistance genes for Cercospora leaf spot disease and bruchids

Development of pyramided mung bean lines carrying resistance genes for Cercospora leaf spot disease and bruchids

Molecular Typing of Potentially Pathogenic Escherichia coli Isolated from Fresh Pasta Filata Venezuelan Cheeses

Background. Fresh pasta filata cheese is considered as one of the most important foods in the Venezuelan diet. It is typically produced by small-scale producers using raw milk. The objective of this research was to molecularly characterize the pathogenic potential of Escherichia coli strains isolated from pasta filata cheese manufactured and marketed in Venezuela. Methodology. In the period between January and March of 2019, a total of 36 strains of E. coli were isolated from a variety of pasta filata cheeses including 17 samples of mozzarella, 16 of telita, and 3 of guayanés. These strains were isolated according to the Venezuelan Commission of Industrial Standards (COVENIN) and identified by conventional methods (biochemical and phenotypic tests). Antimicrobial susceptibility was determined using the disk diffusion technique. Phylogenetic grouping and detection of virulence genes were performed by Polymerase Chain Reaction amplification. Diversity and genetic relationships were determined by Rep-PCR. Results: All strains were susceptible to the tested antibiotics. Phylogroup A (n=19) was the most frequent (52.8%), followed by groups D (n=11; 30.6%), and B1 (n=2; 5.6%). The majority of isolates carried at least two virulence genes, one coding for adhesion mechanisms (fimH) and the other for iron uptake (fyuA). Only one strain of phylogroup A presented a profile consisting of four virulence genes (fimH, fyuA, kpsMT II, and papAH). Four strains that could not be classified according to Clermont's scheme carried resistance genes as well. A heterogeneous population structure was observed by Rep-PCR of the strains. Conclusion: Results support the hypothesis that the E. coli strains isolated from the three types of pasta filata cheeses manufactured and marketed in Venezuela have identical characteristics and virulence factors to Extraintestinal Pathogenic E. coli strains observed in animals and humans, posing a potential health risk. Therefore, it is essential to improve hygienic and sanitary controls at all stages of cheese production and to implement measures for epidemiological surveillance of potentially pathogenic bacterial strains present in Venezuelan, artisanal pasta filata cheeses.

Genomic characterization of methicillin-resistant Staphylococcus aureus isolated from patients attending regional referral hospitals in Tanzania

BackgroundMethicillin-resistant Staphylococcus aureus (MRSA) colonization increases the risk of subsequent infection by MRSA strain complex interlinking between hospital and community-acquired MRSA which increases the chance of drug resistance and severity of the disease.ObjectiveGenomic characterization of Staphylococcus aures strains isolated from patients attending regional referral hospitals in Tanzania.MethodologyA laboratory-based cross-sectional study using short read-based sequencing technology, (Nextseq550,Illumina, Inc. San diego, California, USA). The samples used were collected from patients attending selected regional referral hospitals in Tanzania under the SeqAfrica project. Sequences were analyzed using tools available in the center for genomic and epidemiology server, and visualization of the phylogenetic tree was performed in ITOL 6.0. SPSS 28.0 was used for statistical analysis.ResultsAmong 103 sequences of S. aureus, 48.5% (50/103) carry the mecA gene for MRSA. High proportions of MRSA were observed among participants aged between 18 and 34 years (52.4%), in females (54.3%), and among outpatients (60.5%). The majority of observed MRSA carried plasmids rep5a (92.0%), rep16 (90.0%), rep7c (90.0%), rep15 (82.0%), rep19 (80.0%) and rep10 (72.0%). Among all plasmids observed rep5a, rep16, rep20, and repUS70 carried the blaZ gene, rep10 carried the erm(C) gene and rep7a carried the tet(K) gene. MLST and phylogeny analysis reveal high diversity among MRSA. Six different clones were observed circulating at selected regional hospitals and MRSA with ST8 was dominant.ConclusionThe study reveals a significant presence of MRSA in Staphylococcus aureus strains from Tanzanian regional hospitals, with nearly half carrying the mecA gene. MRSA is notably prevalent among young adults, females, and outpatients, showing high genetic diversity and dominance of ST8. Various plasmids carrying resistance genes indicate a complex resistance profile, highlighting the need for targeted interventions to manage MRSA infections in Tanzania.

Antibiotic resistance gene dynamics in the commensal infant gut microbiome over the first year of life

Colonization of the infant gut is an important developmental process characterized by high carriage of antimicrobial resistance genes (ARGs) and high abundances of pathobionts. The horizontal transfer of ARGs to pathogenic bacteria represents a major public health concern. However, there is still a paucity of longitudinal studies surveilling ARGs in healthy infant guts at high temporal resolution. Furthermore, we do not yet have a clear view of how temporal variation in ARG carriage relates to the dynamics of specific bacterial populations, as well as community virulence potential. Here, we performed deep shotgun metagenomic sequencing of monthly fecal samples from a cohort of 12 infants, covering the first year of life to interrogate the infant gut microbiome for ARG content. We further relate ARG dynamics to the dynamics of taxa, virulence potential, as well as the potential for ARG mobilization. We identify a core resistome dominated by efflux systems typically associated with Enterobacteriaceae. Overall ARG carriage declined over the first year of life and showed strong contemporaneous correlation with the population dynamics of Proteobacteria. Furthermore, the majority of ARGs could be further mapped to metagenome-assembled genomes (MAGs) classified to this phylum. We were able to assign a large number of ARGs to E. coli by correlating the temporal dynamics of individual genes with species dynamics, and we show that the temporal dynamics of ARGs and virulence factors are highly correlated, suggesting close taxonomic associations between these two gene classes. Finally, we identify ARGs linked with various categories of mobile genetic elements, demonstrating preferential linkage among mobility categories and resistance to different drug classes. While individual variation in ARG carriage is substantial during infancy there is a clear reduction over the first year of life. With few exceptions, ARG abundances closely track the dynamics of pathobionts and community virulence potential. These findings emphasize the potential for development of resistant pathogens in the developing infant gut, and the importance of effective surveillance in order to detect such events.

Exploring the Role of the Environment as a Reservoir of Antimicrobial-Resistant Campylobacter: Insights from Wild Birds and Surface Waters.

Antimicrobial resistance (AMR) is a growing global health challenge, compromising bacterial infection treatments and necessitating robust surveillance and mitigation strategies. The overuse of antimicrobials in humans and farm animals has made them hotspots for AMR. However, the spread of AMR genes in wildlife and the environment represents an additional challenge, turning these areas into new AMR hotspots. Among the AMR bacteria considered to be of high concern for public health, Campylobacter has been the leading cause of foodborne infections in the European Union since 2005. This study examines the prevalence of AMR genes and virulence factors in Campylobacter isolates from wild birds and surface waters in Luxembourg. The findings reveal a significant prevalence of resistant Campylobacter strains, with 12% of C. jejuni from wild birds and 37% of C. coli from surface waters carrying resistance genes, mainly against key antibiotics like quinolones and tetracycline. This study underscores the crucial role of the environment in the spread of AMR bacteria and genes, highlighting the urgent need for enhanced surveillance and control measures to curb AMR in wildlife and environmental reservoirs and reduce transmission risks to humans. This research supports One Health approaches to tackling antimicrobial resistance and protecting human, animal, and environmental health.

Genomic Evaluation of Multidrug-Resistant Extended-Spectrum β-Lactamase (ESBL)-Producing Escherichia coli from Irrigation Water and Fresh Produce in South Africa: A Cross-Sectional Analysis.

Escherichia coli, both commensal and pathogenic, can colonize plants and persist in various environments. It indicates fecal contamination in water and food and serves as a marker of antimicrobial resistance. In this context, 61 extended-spectrum β-lactamase (ESBL)-producing E. coli from irrigation water and fresh produce from previous studies were characterized using whole genome sequencing (Illumina MiSeq). The Center for Genomic Epidemiology and Galaxy platforms were used to determine antimicrobial resistance genes, virulence genes, plasmid typing, mobile genetic elements, multilocus sequence typing (MLST), and pathogenicity prediction. In total, 19 known MLST groups were detected among the 61 isolates. Phylogroup B1 (ST58) and Phylogroup E (ST9583) were the most common sequence types. The six ST10 (serotype O101:H9) isolates carried the most resistance genes, spanning eight antibiotic classes. Overall, 95.1% of the isolates carried resistance genes from three or more classes. The blaCTX-M-1, blaCTX-M-14, and blaCTX-M-15 ESBL genes were associated with mobile genetic elements, and all of the E. coli isolates showed a >90% predicted probability of being a human pathogen. This study provided novel genomic information on environmental multidrug-resistant ESBL-producing E. coli from fresh produce and irrigation water, highlighting the environment as a reservoir for multidrug-resistant strains and emphasizing the need for ongoing pathogen surveillance within a One Health context.

Breaking the Cycle: A Yeast Mannan-Rich Fraction Beneficially Modulates Egg Quality and the Antimicrobial Resistome Associated with Layer Hen Caecal Microbiomes under Commercial Conditions.

Antibiotics and antibiotic growth promoters have been extensively employed in poultry farming to enhance growth performance, maintain bird health, improve nutrient uptake efficiency, and mitigate enteric diseases at both sub-therapeutic and therapeutic doses. However, the extensive use of antimicrobials in poultry farming has led to the emergence of antimicrobial resistance (AMR) in microbial reservoirs, representing a significant global public health concern. In response, non-antibiotic dietary interventions, such as yeast mannan-rich fraction (MRF), have emerged as a promising alternative to modulate the gut microbiota and combat the AMR crisis. This study investigated whether a yeast mannan-rich fraction containing feed supplement impacted the performance of laying hens, their microbiomes, and the associated carriage of antimicrobial resistance genes under commercial conditions. High-throughput DNA sequencing was utilised to profile the bacterial community and assess changes in the antibiotic resistance genomes detected in the metagenome, the "resistome", in response to MRF supplementation. It was found that supplementation favourably influenced laying hen performance and microbial composition. Notably, there was a compositional shift in the MRF supplemented group associated with a lower relative abundance of pathobionts, e.g., Escherichia, Brachyspira and Trueperella, and their AMR-encoded genes, relative to beneficial microbes. Overall, the findings further demonstrate the ability of prebiotics to improve laying hen performance through changes associated with their microbiome and resistome.