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Muthuirulandi Sethuvel, D. P.

Publications and source records attributed to Muthuirulandi Sethuvel, D. P..

8 recordsLinked to original sources

ompC/F mutations drive XDR phenotype and lineage defining super clones of E. coli: Sequential events and consequences

Multi-drug resistant Escherichia coli is an increasing public health problem. Though, PBP3 insertions with blaNDM, blaCMY and blaOXA-48 like is restricted to South-East Asia with few reports from USA. The study suggests ompC/F variants as a core factor to classify ESBL (E), non-ESBL (NE), and ESBL with PBP3 and carbapenemases (EPBP3) clones. EPBP3 results in treatment complication, as most of the time, E. coli with PBP3 insertions co-carries blaNDM (87.5%), blaCMY (96.3%) and blaOXA-48 like (88.8%) implicating it as a predisposing factor for carbapenemase gene acquirement. Cefiderocol and cefepime/zidebactam are the choice against EPBP3 E. coli. Evolutionary BEAST analysis revealed consecutive events of YRIN and YRIK insertions in PBP3 gene leading to a surge in MDR E. coli clones. Further, emergence of the super clones STs 410, 405, 167 and 617 featuring these phenotypes is a major threat for developing and developed countries, which needs close monitoring. ImportanceThe manuscript describes various E. coli resistant genotypes across the globe and their importance in the choice of antimicrobial for treatment. The study identified six clades based on ompC and ompF mutations with a strong correlation to PBP3 insertions co-carried with beta-lactamases including blaNDM. Though, the ompC and ompF mutations were reported to precede the acquisition of carbapenemases in E. coli, clade segregation based on AMR genes as observed in this study reveals the ompC and ompF genes as a potential biomarker for AMR clade identification in E. coli. Currently, cefiderocol and cefepime/zidebactam seems to be the only choice to cover the AMR mechanism mediated by PBP3 insertions. Further, emergence of the super clones STs 410, 405, 167 and 617 featuring these PBP3 phenotypes is a major threat for developing and developed countries, which needs close monitoring.

genomics↗

Re-sensitising XDR biofilms using a combination of bacteriophage cocktails and colistin: a natural approach

Persistent antibiotic use results in the rise of antimicrobial resistance with limited or no choice for multidrug resistant (MDR) and extensively drug resistant (XDR) bacteria. This necessitates a need for alternative therapy to effectively combat clinical pathogens that are resistant to last resort antibiotics. The study investigates hospital sewage as a potential source of bacteriophages to control MDR/XDR bacterial pathogens. 81 samples were screened for phages against selected clinical pathogens. 10 phages were isolated against A. baumannii, 5 phages against K. pneumoniae and 16 phages obtained against P. aeruginosa. The novel phages were observed to be strain-specific with a complete growth inhibition of up to 6 hrs. Phage plus colistin combinations further reduced the MBEC of colistin up to 16 folds. Notably, cocktail of phages exhibited supreme efficacy with complete killing at 0.5-1 {micro}g/ml colistin concentrations. Thus, phages specific to clinical strains has a higher edge in treating nosocomial pathogens with their proven anti-biofilm efficacy. In addition, analysis of phage genomes revealed close phylogenetic relations with phages reported from Europe, China and other neighbouring countries. This study serves as a reference and can be extended to other antibiotics and phage types to assess optimum synergistic combinations to combat various drug resistant pathogens in the ongoing AMR crisis.

microbiology↗

Mosaic antimicrobial resistance/virulence plasmid in hypervirulent ST2096 Klebsiella pneumoniae in India: The rise of a new superbug?

Hypervirulent K. pneumoniae (HvKp) is typically associated with ST23 clone; however, hvKp is also emerging from clones ST11, ST15 and ST147, which are also multi-drug resistant (MDR). Here, we aimed to characterise nine novel MDR hvKp isolates harbouring mosaic plasmids simultaneously carrying antimicrobial resistance (AMR) and virulence genes. Nine HvKp isolates obtained from hospitalised patients in southern India were characterized for antimicrobial susceptibility and hypervirulence phenotypes. All nine hvKp isolates were subjected to whole genome sequencing (WGS) using Ilumina HiSeq2500 and a subset of four were sequenced using Oxford Nanopore MinION. Among the nine isolates, seven were carbapenem-resistant, two of which carried blaNDM-5 on an IncFII plasmid and five carried blaOXA-232 on a ColKP3 plasmid. The virulence determinants were encoded in a mosaic plasmid ([~]320 Kbp) that formed as a result of its insertion in a IncFIB-IncHI1B plasmid co-integrate. The mosaic plasmid carried AMR genes (aadA2, armA, blaOXA-1, msrE, mphE, sul1 and dfrA14) in addition to rmpA2, iutA and iucABCD virulence genes. Interestingly the mosaic plasmid carried its own type IV-A3 CRISPR-cas system that is likely able to target the acquisition of IncF plasmid with the help of a traL spacer. The convergence of virulence and AMR is the biggest threat among invasive K. pneumoniae infections. However, increasing reports of the presence of mosaic plasmid carrying both AMR and virulence genes suggests MDR-hvKp isolates are no longer confined to selected clones and the containment of such isolates is very challenging. IMPORTANCEKlebsiella pneumoniae is an opportunistic pathogen that commonly associated with hospital-acquired infections in the urinary tract, respiratory tract, lung, wound sites. The organism has gained notoriety by acquiring additional genetic traits to become either hypervirulent (HV) phenotype or multidrug resistant (MDR) phenotype. Though the infections by both these phenotypes were very challenging to treat, the MDR K. pneumonia (MDR-Kp) were remained in the hospital settings while HV K. pneumonia (hvKp) strains were mostly originated from the community settings. In a recent turn of events, the evolution of MDR-Kp and hvKp has converged as both clones found to carry both MDR plasmids and virulence plasmid. These convergent strains are challenging to treat and is associated with higher mortality rate. As the recent hvKp isolates harbour mosaic plasmid encoding both AMR and virulence determinants there is a need to investigate the evolution of these pathogens. The significance of our research is in characterising the novel mosaic plasmid identified in MDR-hvKp isolates that belong sequence type (ST) 2096. Tracking the possible evolution pathway of MDR-hvKPs would greatly help in the proper surveillance and management of this superbugs. RepositoriesThe whole genome sequences of the present study isolates have been deposited in GenBank, NCBI, with accession numbers CP053765 - CP053770, CP053771 - CP053780, CP058798-CP058806, JAARNO010000001.1 - JAARNO010000005.1, JAAQSG000000000, JAARNJ000000000, JAARMH000000000 and JAAQTC000000000

genomics↗

The influence of biofilm formation on carbapenem resistance in clinical Klebsiella pneumoniae infections: phenotype vs genome-wide analysis

Klebsiella pneumoniae is one of the leading causes of nosocomial infections. Carbapenem-resistant (CR) K. pneumoniae are on the rise in India. The biofilm forming ability of K. pneumoniae further complicates patient management. There is still a knowledge gap on the association of biofilm formation with patient outcome and carbapenem susceptibility, which is investigated in the present study.K. pneumoniae isolates from patients admitted in critical care units with catheters and ventilators were included. K. pneumoniae (n = 72) were tested for antimicrobial susceptibility as recommended by CLSI 2019 and subjected to 96-well microtitre plate biofilm formation assay. Based on optical density at 570 nm isolates were graded as strong, moderate and weak biofilm formers. Subset of strong biofilm formers were subjected to whole genome sequencing and a core genome phylogenetic analysis in comparison with global isolates were performed. Biofilm formation was compared for an association with the carbapenem susceptibility and with patient outcome. Statistical significance, correlations and graphical representation were performed using SPSS v23.0.Phenotypic analyses showed a positive correlation between biofilm formation and carbapenem resistance. Planktonic cells observed to be susceptible in vitro exhibited higher MICs in biofilm structure. The biofilm forming ability had a significant association with the morbidity/mortality. Infections by stronger biofilm forming pathogens significantly (P<0.05) resulted in fewer ‘average days alive’ for the patient (3.33) in comparison to those negative for biofilms (11.33). Phylogenetic analysis including global isolates revealed the clear association of sequence types with genes for biofilm mechanism and carbapenem resistance. Carbapenemase genes were found specific to each clade. The known hypervirulent clone-ST23 with wcaG, magA, rmpA, rmpA2 and wzc with a lack of mutation for hyper-capsulation might be poor biofilm formers. Interestingly, ST15, ST16, ST307 and ST258 – reported global high-risk clones were wcaJ negative indicating the high potential of biofilm forming capacity. Genes wabG and treC for CPS, bcsA and pgaC for adhesins, luxS for quorum sensing were common in all clades in addition to genes for aerobactin (iutA), allantoin (allS), type I and III fimbriae (fimA, fimH, mrkD) and pili (pilQ, ecpA).This study is the first of its kind to compare genetic features of antimicrobial resistance with a spectrum covering most of the genetic factors for K. pneumoniae biofilm. These results highlight the importance of biofilm screening to effectively manage nosocomial infections by K. pneumoniae. Further, data obtained on epidemiology and associations of biofilm and antimicrobial resistance genetic factors will serve to enhance our understanding on biofilm mechanisms in K. pneumoniae.Competing Interest StatementThe authors have declared no competing interest.View Full Text

genomics↗

Phylogenetic and evolutionary analysis reveals the recent dominance of ciprofloxacin resistant S. sonnei and local persistence of S. flexneri clones in India

Shigella is the second leading cause of bacterial diarrhea worldwide. Recently S. sonnei seems to be replacing S. flexneri in low and middle-income countries undergoing economic development. Despite this, studies focusing on these species at genomic level remain largely unexplored. Here we compared the genome sequences of S. flexneri and S. sonnei isolated from India with the publically available genomes of global strains. Our analysis provide evidence for the long term persistence of all PGs of S. flexneri and the recent dominance of ciprofloxacin-resistant S. sonnei lineage in India. Within S. flexneri PGs, majority of the study isolates belonged to PG3 within the predominance of serotype 2. For S. sonnei, the current pandemic involves globally distributed MDR clones that belong to Central Asia lineage III. The presence of such epidemiologically-dominant lineages in association with stable AMR determinants results in the successful survival in the community.

genomics↗

First Indian report on Genome-wide Comparison of Multidrug-Resistant Escherichia coli from Blood Stream Infections

BackgroundMultidrug-resistant (MDR) E. coli with extended-spectrum {beta}-lactamases (ESBLs) is becoming endemic in health care settings around the world. Baseline data on virulence and AMR of specific lineages of E. coli circulating in developing countries like India is currently lacking.\n\nMethodsWhole-genome sequencing was performed for 60 MDR E. coli isolates. Genome-wide analysis was performed at single nucleotide polymorphism (SNP) level resolution to identify the relation between the isolates in context of time, virulence and AMR determinants possessed.\n\nResultsGenome comparison revealed the presence of ST-131 global MDR and ST410 as emerging-MDR clades of E. coli. AMR gene profile for cephalosporin and carbapenem resistance differed between the clades. Genotypes blaCTX-M-15 and blaNDM-5 were common among cephalosporinases and carbapenemases, respectively. For aminoglycoside resistance, rmtB was positive for 31.7% of the isolates, of which 30% were co-harboring carbapenemases. Further, the FimH types and virulence gene profile positively correlated with the SNP based phylogeny, which also revealed the evolution of MDR clones among the study population with temporal accumulation of SNPs. The predominant clone was ST167 (blaNDM lineage) followed by ST405 (global clone ST131 equivalent) and ST410 (fast spreading high risk clone).\n\nConclusionsThis is the first report on the whole genome analysis of MDR E. coli lineages circulating in India. Data from this study will provide public health agencies a baseline portfolio of AMR and virulence in pathogenic E. coli in the region.

genomics↗

First hybrid complete genome of Aeromonas veronii reveals chromosome-mediated novel structural variant mcr-3.19 from human clinical specimen

BackgroundRecent findings substantiate the origin of plasmid-mediated colistin resistance gene mcr-3 from Aeromonads. The present study aimed to screen the plasmid-mediated colistin resistance among 30 clinical multidrug resistant (MDR) Aeromonas spp.\n\nResultsThe presence of mcr-1, mcr-2, mcr-3, and mcr-4 were screened by PCR, which revealed mcr-3 in a colistin susceptible isolate (FC951). All other isolates were negative for mcr genes. Sequencing of FC951 revealed that mcr-3 (mcr-3.19) identified was different from previously reported variants and had 95.62 and 95.28% nucleotide similarity with mcr-3.3 and mcr-3.10 gene. A hybrid assembly using IonTorrent and MinION reads revealed structural genetic information of mcr-3.19 with an insertion of ISAs18 within the gene. Due to this, mcr-3.19 was non-expressive which makes FC951 susceptible to colistin. Further, in silico sequence and protein structural analysis confirmed the new variant. To the best of our knowledge, this is the first report on novel mcr-3 variant (mcr-3.19).\n\nConclusionsThe significant role of mcr-like genes in different Aeromonas species remains unknown and needs additional investigation to understand the insights on colistin resistance mechanism.

microbiology↗

Genetic diversity of clinical Bordetella pertussis ST2 strains in comparison with vaccine reference strains of India

Pertussis is a highly contagious disease of the respiratory tract caused by Bordetella pertussis, a bacteria that lives in the mouth, nose, and throat. Current study reports the highly accurate complete genomes of two clinical B. pertussis strains from India for the first time. The analysis revealed insertional elements flanked by IS481, which has been previously regarded as the important component for bacterial evolution. The two B. pertussis clinical strains exhibited diversity through genome degradation when compared to whole-cell pertussis vaccine reference strains of India. These isolates harboured multiple genetic virulence traits and toxin subunits, which belonged to sequence type ST2. The genome information of Indian clinical B. pertussis strains will serve as a baseline data to decipher more information on the genome evolution, virulence factors and their role in pathogenesis for effective vaccine strategies.

microbiology↗