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1.
Sci Rep ; 14(1): 7331, 2024 03 27.
Artigo em Inglês | MEDLINE | ID: mdl-38538851

RESUMO

The selection of stable reference genes for the normalization of reverse transcription quantitative real-time PCR (RT-qPCR) is generally overlooked despite being the crucial element in determining the accuracy of the relative expression of genes. In the present study, the stability of seven candidate reference genes: actin (act), α-tubulin (atub), ß-tubulin (btub), translation elongation factor 1-α (ef1), elongation factor 2 (ef2), ubiquitin-conjugating enzyme (ubc) and 40S ribosomal protein S3A (ws21) in Phytophthora capsici has been validated. The validation was performed at six infection time points during its interaction with its susceptible host Piper nigrum, two developmental stages, and for the combined dataset. Four algorithms: geNorm, NormFinder, BestKeeper, and the ΔCt method were compared, and a comprehensive ranking order was produced using RefFinder. The overall analysis revealed that ef1, ws21, and ubc were identified as the three most stable genes in the combined dataset, ef1, ws21, and act were the most stable at the infection stages, and, ef1, btub, and ubc were most stable during the developmental stages. These findings were further corroborated by validating the P. capsici pathogenesis gene NPP1 expression. The findings are significant as this is the first study addressing the stability of reference genes for P. capsici-P. nigrum interaction studies.


Assuntos
Phytophthora , Piper nigrum , Reação em Cadeia da Polimerase em Tempo Real/métodos , Phytophthora/genética , Algoritmos , Genes de Plantas , Padrões de Referência , Perfilação da Expressão Gênica/métodos
2.
Microbiol Spectr ; 12(2): e0251123, 2024 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-38214512

RESUMO

Colistin resistance in Acinetobacter baumannii is mediated by multiple mechanisms. Recently, mutations within pmrABC two-component system and overexpression of eptA gene due to upstream insertion of ISAba1 have been shown to play a major role. Thus, the aim of our study is to characterize colistin resistance mechanisms among the clinical isolates of A. baumannii in India. A total of 207 clinical isolates of A. baumannii collected from 2016 to 2019 were included in this study. Mutations within lipid A biosynthesis and pmrABC genes were characterized by whole-genome shotgun sequencing. Twenty-eight complete genomes were further characterized by hybrid assembly approach to study insertional inactivation of lpx genes and the association of ISAba1-eptA. Several single point mutations (SNPs), like M12I in pmrA, A138T and A444V in pmrB, and E117K in lpxD, were identified. We are the first to report two novel SNPs (T7I and V383I) in the pmrC gene. Among the five colistin-resistant A. baumannii isolates where complete genome was available, the analysis showed that three of the five isolates had ISAba1 insertion upstream of eptA. No mcr genes were identified among the isolates. We mapped the SNPs on the respective protein structures to understand the effect on the protein activity. We found that majority of the SNPs had little effect on the putative protein function; however, some SNPs might destabilize the local structure. Our study highlights the diversity of colistin resistance mechanisms occurring in A. baumannii, and ISAba1-driven eptA overexpression is responsible for colistin resistance among the Indian isolates.IMPORTANCEAcinetobacter baumannii is a Gram-negative, emerging and opportunistic bacterial pathogen that is often associated with a wide range of nosocomial infections. The treatment of these infections is hindered by increase in the occurrence of A. baumannii strains that are resistant to most of the existing antibiotics. The current drug of choice to treat the infection caused by A. baumannii is colistin, but unfortunately, the bacteria started to show resistance to the last-resort antibiotic. The loss of lipopolysaccharides and mutations in lipid A biosynthesis genes are the main reasons for the colistin resistance. The present study characterized 207 A. baumannii clinical isolates and constructed complete genomes of 28 isolates to recognize the mechanisms of colistin resistance. We showed the mutations in the colistin-resistant variants within genes essential for lipid A biosynthesis and that cause these isolates to lose the ability to produce lipopolysaccharides.


Assuntos
Infecções por Acinetobacter , Acinetobacter baumannii , Humanos , Colistina/farmacologia , Acinetobacter baumannii/genética , Lipídeo A , Proteínas de Bactérias/genética , Farmacorresistência Bacteriana/genética , Infecções por Acinetobacter/microbiologia , Testes de Sensibilidade Microbiana , Antibacterianos/farmacologia , Genômica , Carbapenêmicos/farmacologia
3.
Infect Dis Ther ; 12(5): 1319-1335, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-37062023

RESUMO

INTRODUCTION: The objective of this study was to examine the evolution of carbapenem-resistant Klebsiella pneumoniae (CRKp) infections and their impact at a tertiary care hospital in South India. METHODS: A comparative analysis of clinical data from two prospective cohorts of patients with CRKp bacteremia (C1, 2014-2015; C2, 2021-2022) was carried out. Antimicrobial susceptibilities and whole genome sequencing (WGS) data of selected isolates were also analyzed. RESULTS: A total of 181 patients were enrolled in the study, 56 from C1 and 125 from C2. CRKp bacteremia shifted from critically ill patients with neutropenia to others (ICU stay: C1, 73%; C2, 54%; p = 0.02). The overall mortality rate was 50% and the introduction of ceftazidime-avibactam did not change mortality significantly (54% versus 48%; p = 0.49). Oxacillinases (OXA) 232 and 181 were the most common mechanisms of resistance. WGS showed the introduction of New Delhi metallo-ß-lactamase-5 (NDM-5), higher genetic diversity, accessory genome content, and plasmid burden, as well as increased convergence of hypervirulence and carbapenem resistance in C2. CONCLUSIONS: CRKp continues to pose a significant clinical threat, despite the introduction of new antibiotics. The study highlights the evolution of resistance and virulence in this pathogen and the impact on patient outcomes in South India, providing valuable information for clinicians and researchers.

4.
Eur J Clin Microbiol Infect Dis ; 42(5): 645-651, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-36905566

RESUMO

Carbapenem-resistant Acinetobacter baumannii (CRAB) is often difficult to treat. Considering the current circumstances, there is an unquestionable need for new therapeutic options to treat CRAB infections. In the present study, the synergistic activity of sulbactam-based combination was determined against genetically characterized CRAB isolates. Non-duplicate CRAB isolates (n = 150) recovered from blood culture and endotracheal aspirates were included in this study. The minimum inhibitory concentrations (MICs) of tetracyclines (minocycline, tigecycline, eravacycline) and their comparators (meropenem, sulbactam, cefoperazone/sulbactam, ceftazidime/avibactam, and colistin) were determined using the microbroth dilution method. Six isolates were tested for the synergistic activity of various sulbactam-based combinations using time-kill experiments. Tigecycline and minocycline showed a wide spread of MICs with most isolates in the range of 1 to 16 mg/L. The MIC90 of eravacycline (0.5 mg/L) was four dilutions lower than that of tigecycline (8 mg/L). Minocycline with sulbactam was the most active dual combination against OXA-23 like (n = 2) and NDM with OXA-23 like producers (n = 1), which resulted in ≥ 2 log10 kill. The combination of ceftazidime-avibactam with sulbactam showed ≥ 3 log10 kill against all the three tested OXA-23 like producing CRAB isolates, but showed no activity against dual carbapenemase producers. Sulbactam with meropenem showed ≥ 2 log10 kill against one OXA-23 like producing CRAB isolate. The findings suggest that sulbactam-based combination may confer therapeutic benefits against CRAB infections.


Assuntos
Infecções por Acinetobacter , Acinetobacter baumannii , Humanos , Sulbactam/farmacologia , Sulbactam/uso terapêutico , Minociclina/uso terapêutico , Meropeném/uso terapêutico , Tigeciclina/uso terapêutico , Infecções por Acinetobacter/tratamento farmacológico , Infecções por Acinetobacter/microbiologia , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Testes de Sensibilidade Microbiana , Sinergismo Farmacológico
5.
J Oral Maxillofac Pathol ; 26(2): 259-262, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35968168

RESUMO

Glomus tumors are uncommon, benign solitary tumors derived from the glomus apparatus. We report here a case of a malignant glomus tumor in an 8-year-old child presenting as a multilocular ill-defined radiolucency of the mandible. The lesion microscopically showed sheets of round basophilic cells with high nuclear-cytoplasmic ratio, indistinct cell boundaries, nuclear hyperchromatism and nuclear pleomorphism. Immunohistochemically, the tumor was positive for vimentin and smooth muscle actin.

6.
Front Microbiol ; 13: 869653, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35783393

RESUMO

With the excessive genome plasticity, Acinetobacter baumannii can acquire and disseminate antimicrobial resistance (AMR) genes often associated with mobile genetic elements (MGEs). Analyzing the genetic environment of resistance genes often provides valuable information on the origin, emergence, evolution, and spread of resistance. Thus, we characterized the genomic features of some clinical isolates of carbapenem-resistant A. baumannii (CRAb) to understand the role of diverse MGEs and their genetic context responsible for disseminating carbapenem resistance genes. For this, 17 clinical isolates of A. baumannii obtained from multiple hospitals in India between 2018 and 2019 were analyzed. AMR determinants, the genetic context of resistance genes, and molecular epidemiology were studied using whole-genome sequencing. This study observed an increased prevalence of bla OXA-23 followed by dual carbapenemases, bla OXA-23 , and bla NDM . This study identified three novel Oxford MLST sequence types. The majority of the isolates belonged to the dominant clone, IC2, followed by less prevalent clones such as IC7 and IC8. This study identified variations of AbaR4 and AbGRI belonging to the IC2 lineage. To the best of our knowledge, this is the first study that provides comprehensive profiling of resistance islands, their related MGEs, acquired AMR genes, and the distribution of clonal lineages of CRAb from India.

7.
J Cell Biochem ; 122(12): 1946-1957, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34597421

RESUMO

Emerging nosocomial strains of Acinetobacter baumannii are of recent concern as they are expressing extensive drug resistance (XDR). Using whole-genome sequencing and molecular characterisation analysis, the current study reveals the presence of carbapenemase genes in 92.86% of studied Indian isolates. These included blaOXA-51 , blaOXA-23 , blaOXA-58 , and blaNDM genes, with over a third expressing dual carbapenemase genes. As per the MLST scheme, IC2Oxf /CC2Pas was the predominant clone, with 57.14% isolates belonging to this lineage. The presence of these carbapenemase genes resulted in sulbactam (SUL) resistance (MIC: 16-256 µg/ml) in all of the studied isolates. The efficacy of durlobactam (DUR), a novel ß-lactamase inhibitor that also inhibits PBP2 was assessed through in silico intermolecular interaction analysis. Several nonsynonymous single nucleotide polymorphisms were identified in PBP2 (G264S, I108V, S259T) and PBP3 (A515V, T526S) sequences. Minimal variations were recorded in the protein backbone dynamics in active-site motifs of wild-type and mutants, which correlated with negligible binding energy fluctuations for the PBP3-SUL (-5.85 ± 0.04 kcal/mol) and PBP2-DUR (-5.16 ± 0.66 kcal/mol) complexes. Furthermore, higher binding affinities and low inhibition constants were noted in OXA23-DUR (-7.36 kcal/mol; 4.01 µM), OXA58-DUR (-6.44 kcal/mol; 19.07 µM), and NDM-DUR (-6.82 kcal/mol; 10.01 µM) complexes when compared with the conventional drugs avibactam and aztreonam. Stable interaction profiles of DUR with carbapenemases can possibly restore SUL activity against both PBP3WT and PBP3MTs . The study establishes the efficacy of the novel SUL-DUR combination as a successful treatment strategy in combating emerging XDR strains of A. baumannii.


Assuntos
Infecções por Acinetobacter , Acinetobacter baumannii , Compostos Azabicíclicos/farmacologia , Farmacorresistência Bacteriana Múltipla , Mutação , Proteínas de Neoplasias , Sulbactam/farmacologia , Infecções por Acinetobacter/tratamento farmacológico , Infecções por Acinetobacter/genética , Infecções por Acinetobacter/metabolismo , Acinetobacter baumannii/genética , Acinetobacter baumannii/metabolismo , Combinação de Medicamentos , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Farmacorresistência Bacteriana Múltipla/genética , Humanos , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismo
8.
Access Microbiol ; 2(8): acmi000140, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32974602

RESUMO

Carbapenem resistance in Acinetobacter baumannii is due to bla OXA-23, which is endemic in India. Recently, the sporadic presence of bla OXA-58 as well as the occurrence of dual carbapenemases were observed. The mobility as well as the dissemination of these resistance genes were mainly mediated by various mobile genetic elements. The present study was aimed at characterizing the genetic arrangement of bla OXA-23, bla NDM-1 and bla OXA-58 identified in two complete genomes of carbapenem-resistant A. baumannii (CRAB). Complete genomes obtained using a hybrid-assembly approach revealed the accurate arrangement of Tn2006 with bla OXA-23, ISAba125 with bla NDM and ISAba3 with bla OXA-58. In addition, the association of IntI1 integrase with the bla CARB-2 gene and several virulence factors required for type-IV pili assembly, motility and biofilm formation have been identified. The current study provided deeper insight into the complete characterization of insertion sequences and transposons associated with the carbapenem-resistant genes using short reads of IonTorrent PGM and long reads of MinIon in A. baumannii .

9.
Indian J Med Microbiol ; 38(1): 24-31, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32719205

RESUMO

Background: Acinetobacter baumannii has become a common pathogen causing hospital-acquired infections (HAIs). Although acquiring any nosocomial infection is associated with increased mortality, we do not know if the acquisition of Acinetobacter infection confers a worse prognosis as compared to non-Acinetobacter-related HAI. The aim of the current study is to compare the clinical outcomes of ventilator-associated pneumonia (VAP) and central line associated blood stream infections (CLABSIs) caused by A. baumannii with those caused by other bacterial pathogens. Materials and Methods: This prospective cohort study was conducted among critically ill adults admitted to a tertiary care hospital in South India from January 2013 to June 2014. We enrolled patients who developed new-onset fever ≥48 h after admission and fulfilled pre-specified criteria for VAP or CLABSI. The patients were followed up until the primary outcomes of death or hospital discharge. Results: During the study period, 4047 patients were admitted in the intensive care units, among which 129 eligible HAI events were analysed. Of these, 95 (73.6%) were VAP, 34 (26.4%) were CLABSI, 78 (60.4%) were A. baumannii-related HAI (AR-HAI) and 51 (39.6%) were non-A. baumannii-related HAI (NAR-HAI). Mortality among AR-HAI was 57.6% compared to 39.2% in NAR-HAI (P = 0.04) which on multivariate analysis did not achieve statistical significance, although the trend persisted (odds ratio [OR] = 4.2, 95% confidence interval [CI]: 0.95-18.4, P = 0.06). The acquisition of VAP due to A. baumannii was associated with poor ventilator outcomes even after adjusting for confounders (adjusted OR = 3.5, 95% CI: 1.07-11.6, P = 0.04). Conclusion: In our cohort of critically ill adults with VAP and CLABSI, AR-HAI was associated with poor ventilator outcomes and a trend towards higher mortality. These findings add to the evidence suggesting that A. baumannii is a dangerous pathogen, perhaps even more so than others.


Assuntos
Infecções por Acinetobacter/mortalidade , Acinetobacter baumannii/isolamento & purificação , Pneumonia Associada à Ventilação Mecânica/microbiologia , Pneumonia Associada à Ventilação Mecânica/mortalidade , Adulto , Estado Terminal/mortalidade , Farmacorresistência Bacteriana Múltipla , Feminino , Seguimentos , Humanos , Índia , Unidades de Terapia Intensiva , Tempo de Internação , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Resultado do Tratamento
10.
J Infect Public Health ; 13(7): 1022-1028, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31874816

RESUMO

OBJECTIVES: Acinetobacter baumannii emerged as a major nosocomial pathogen responsible for infections. In this study, we report the molecular characterization, association of insertion sequences and sequence types of clinical isolates of carbapenem resistant A. baumannii. MATERIALS AND METHODS: A total of 763 non-duplicate isolates of A. baumannii received from 8 centres across India during January 2014 to December 2017 were studied. Susceptibility testing was done by Kirby-Bauer method. PCR was performed for detection of extended spectrum ß-lactamases, metallo ß-lactamases, oxacillinases and ISAba1. Mapping PCR was performed to identify the position of ISAba1 with respect to blaOXA-23 like and blaOXA-51 like gene. MLST was performed to identify the sequence type. Whole genome sequencing was done to decipher the genetic arrangement of ISAba1 with blaOXA-23 like and with blaOXA-51 like. RESULTS: All the isolates were resistant to imipenem and meropenem. blaOXA-23 like was the predominant carbapenemase. All isolates were positive for ISAba1. The common sequence types were ST848, ST451 and ST1305 which belongs to International clone II. Whole genome sequencing showed considerable variation in the insertion site location. CONCLUSIONS: In conclusion, high prevalence of blaOXA-23 like in A. baumannii and its association with ISAba1 and sequence types belonging to IC-II facilitates the successful dissemination of these extremely drug resistant strains.


Assuntos
Infecções por Acinetobacter/epidemiologia , Acinetobacter baumannii/efeitos dos fármacos , Acinetobacter baumannii/genética , Carbapenêmicos/farmacologia , Farmacorresistência Bacteriana/genética , Infecções por Acinetobacter/genética , Infecções por Acinetobacter/microbiologia , Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Elementos de DNA Transponíveis/genética , Humanos , Imipenem/farmacologia , Índia , Meropeném/farmacologia , Testes de Sensibilidade Microbiana , Tipagem de Sequências Multilocus , Reação em Cadeia da Polimerase , beta-Lactamases/genética
11.
Indian J Med Microbiol ; 37(2): 147-162, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31745014

RESUMO

The prime goal of molecular epidemiology is to identify the origin and evolution of pathogens, which can potentially influence the public health worldwide. Traditional methods provide limited information which is not sufficient for outbreak investigation and studying transmission dynamics. The recent advancement of next-generation sequencing had a major impact on molecular epidemiological studies. Currently, whole-genome sequencing (WGS) has become the gold standard typing method, especially for clinically significant pathogens. Here, we aimed to describe the application of appropriate molecular typing methods for global antimicrobial resistance surveillance system pathogens based on the level of discrimination and epidemiological settings. This shows that sequence-based methods such as multi-locus sequence typing (MLST) are widely used due to cost-effectiveness and database accessibility. However, WGS is the only method of choice for studying Escherichia coli and Shigella spp. WGS is shown to have higher discrimination than other methods in typing Klebsiella pneumoniae, Acinetobacter baumannii and Salmonella spp. due to its changing accessory genome content. For Gram positives such as Streptococcus pneumoniae, WGS would be preferable to understand the evolution of the strains. Similarly, for Staphylococcus aureus, combination of MLST, staphylococcal protein A or SCCmec typing along with WGS could be the choice for epidemiological typing of hospital- and community-acquired strains. This review highlights that combinations of different typing methods should be used to get complete information since no one standalone method is sufficient to study the varying genome diversity.


Assuntos
Anti-Infecciosos , Doenças Transmissíveis/epidemiologia , Doenças Transmissíveis/etiologia , Resistência Microbiana a Medicamentos , Anti-Infecciosos/farmacologia , Anti-Infecciosos/uso terapêutico , Doenças Transmissíveis/tratamento farmacológico , Doenças Transmissíveis/transmissão , Surtos de Doenças , Geografia , Saúde Global , Humanos , Epidemiologia Molecular , Tipagem Molecular/métodos , Vigilância da População , Sequenciamento Completo do Genoma
12.
Future Sci OA ; 5(6): FSO395, 2019 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-31285840

RESUMO

Acinetobacter species have emerged as one of the most clinically important pathogens. The phenotypic techniques which are currently available are insufficient in accurately identifying and differentiating the closely related and clinically important Acinetobacter species. Here, we discuss the advantages and limitations of the conventional phenotypic methods, automated identification systems, molecular methods and MALDI-TOF in the precise identification and differentiation of Acinetobacter species. More specifically, several species of this genus are increasingly reported to be of high clinical importance. Molecular characterization such as of bla OXA-51-like PCR together with rpoB sequencing has high discriminatory power over the conventional methods for Acinetobacter species identification, especially within the Acinetobacter calcoaceticus-Acinetobacter baumannii complex.

13.
J Pharm Bioallied Sci ; 11(Suppl 2): S285-S288, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31198354

RESUMO

INTRODUCTION: Dermatoglyphics means the study of skin markings or patterns on fingers, hands, and feet. Dermatoglyphics is a heritable trait that is considered as a usual phenotype in criminology. Dermatoglyphics acts as a scientific method for identification of an individual and it is constant till demise. OBJECTIVES: This study was conducted to correlate the dermatoglyphics and blood grouping of 150 dental students. MATERIALS AND METHODS: A pro forma was prepared on a durable white paper, rubber stamp ink pads were used for smearing each finger, imprints were taken, and each pattern of fingerprint was observed by powerful hand lens and recorded. Note was made of the sex, age, and ABO and Rh blood group for studying the relationship between types of fingerprints and relation to ABO and Rh blood type. Fingerprint was taken using the INK method as illustrated by Cummins and Mildo. Fingerprint patterns (loops, whorls, and arches) and blood data were collected. RESULTS: In this study, 38% of subjects belonged to O blood group followed by A, B, and AB, and 96.77% of subjects were Rh-positive and 3.23% were Rh-negative. CONCLUSIONS: This study shows the association between distribution of dermatoglyphics, ABO, Rh blood group, and gender.

14.
Indian J Med Res ; 149(2): 240-246, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-31219089

RESUMO

Background & objectives: Acinetobacter baumannii is an opportunistic pathogen responsible for causing nosocomial infections. A. baumannii develops resistance to various antimicrobial agents including carbapenems, thereby complicating the treatment. This study was performed to characterize the isolates for the presence of various ß-lactamases encoding genes and to type the isolates to compare our clones with the existing international clones across five centres in India. Methods: A total 75 non-repetitive clinical isolates of A. baumannii from five different centres were included in this study. All the isolates were confirmed as A. baumannii by bl aOXA-51-likePCR. Multiplex PCR was performed to identify the presence of extended spectrum ß-lactamases (ESBL) and carbapenemases. Multilocus sequence typing was performed to find the sequence type (ST) of the isolates. e-BURST analysis was done to assign each ST into respective clonal complex. Results: blaOXA-51-likewas present in all the 75 isolates. The predominant Class D carbapenemase was blaOXA-23-likefollowed by Class B carbapenemase, blaNDM-like. Class A carbapenemase was not observed. blaPER-likewas the predominant extended spectrum ß-lactamase. ST-848, ST-451 and ST-195 were the most common STs. Eight-novel STs were identified. e-BURST analysis showed that the 75 A. baumannii isolates were clustered into seven clonal complexes and four singletons, of which, clonal complex 208 was the largest. Interpretation & conclusions: Most of the isolates were grouped under clonal complex 208 which belongs to the international clonal lineage 2. High occurrence of ST-848 carrying blaOXA-23-likegene suggested that ST-848 could be an emerging lineage spreading carbapenem resistance in India.


Assuntos
Infecções por Acinetobacter/tratamento farmacológico , Acinetobacter baumannii/genética , Farmacorresistência Bacteriana Múltipla/genética , beta-Lactamases/genética , Infecções por Acinetobacter/epidemiologia , Infecções por Acinetobacter/genética , Infecções por Acinetobacter/microbiologia , Acinetobacter baumannii/efeitos dos fármacos , Acinetobacter baumannii/patogenicidade , Carbapenêmicos/efeitos adversos , Carbapenêmicos/uso terapêutico , Genótipo , Humanos , Índia/epidemiologia , Testes de Sensibilidade Microbiana , Epidemiologia Molecular , Reação em Cadeia da Polimerase Multiplex
15.
Methods Mol Biol ; 1946: 1-15, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30798539

RESUMO

Specimen collection and processing is an important aspect of clinical microbiology laboratory. The reports are dependent on the quality of the specimen and the time between the collection and processing. Appropriate methodology needs to be followed for the collection, amount, type, labeling, transportation, and processing of the specimens especially for organism like Acinetobacter species. Various biochemical tests are used for identification of various organisms. Such identification depends on the ability of organisms to produce certain enzymes or to utilize certain compound to be identified by biochemical tests.


Assuntos
Acinetobacter , Técnicas Bacteriológicas , Manejo de Espécimes , Acinetobacter/classificação , Acinetobacter/isolamento & purificação , Acinetobacter/fisiologia , Algoritmos , Humanos , Manejo de Espécimes/métodos , Fluxo de Trabalho
16.
Methods Mol Biol ; 1946: 17-22, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30798540

RESUMO

Acinetobacter baumannii is considered to be an important nosocomial pathogen responsible for various outbreaks that have resulted in a need for effective epidemiological typing methods. Different typing methods are available for A. baumannii epidemiological studies. Currently, the phenotypic typing methods are not being used and replaced by various molecular methods. In this chapter, two important epidemiological typing methods, pulsed-field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST), are discussed.


Assuntos
Infecções por Acinetobacter/epidemiologia , Infecções por Acinetobacter/microbiologia , Acinetobacter baumannii/classificação , Acinetobacter baumannii/genética , Infecção Hospitalar/epidemiologia , Infecção Hospitalar/microbiologia , Surtos de Doenças , Técnicas de Genotipagem , Eletroforese em Gel de Campo Pulsado/métodos , Genótipo , Humanos , Epidemiologia Molecular , Tipagem de Sequências Multilocus/métodos
17.
Methods Mol Biol ; 1946: 23-37, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30798541

RESUMO

Serial twofold dilution methods are most commonly used to identify the antimicrobial activities of antibiotics. This can be achieved by different methods like broth dilution or agar dilution. Though these methods are simple, they can be influenced by various experimental factors and result in discrepancy. The following protocol has been validated for Acinetobacter species, including A. baumannii. It is important to include appropriate control strains to determine the minimum inhibitory concentration values and to compare the experiment results.


Assuntos
Acinetobacter/genética , Anti-Infecciosos/farmacologia , Testes de Sensibilidade Microbiana , Infecções por Acinetobacter/tratamento farmacológico , Infecções por Acinetobacter/microbiologia , Antibacterianos/farmacologia , Testes de Sensibilidade a Antimicrobianos por Disco-Difusão , Humanos , Testes de Sensibilidade Microbiana/métodos , Fluxo de Trabalho
18.
J Med Microbiol ; 67(9): 1340-1347, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30016226

RESUMO

PURPOSE: This study aimed to characterize A. baumannii strains isolated from patients in an intensive care unit (ICU) setting. Molecular techniques were used to study clonal relatedness and determine a fast, efficient and cost-effective way of detecting persistent clones. METHODOLOGY: A. baumannii (n=17) were obtained in June and November 2015 from a single ICU setting in South India. DNA typing methods such as multilocus sequence typing (MLST), single-locus sequence-based typing (SBT) and DNA fingerprinting PCRs (M13, DAF4 and ERIC2) were employed to understand the association of clones. PCRs were performed for the antimicrobial resistance genes ISAba1-blaOXA-51-like, ISAba1-blaOXA-23-like, blaNDM-1, blaPER-7 and blaTEM-1, and the virulence genes cpa 1, cpa2 and pkf. RESULTS: The MLST showed some degree of corroboration with the other DNA typing methods. The M13 PCR was found to give better results than the other fingerprinting methods. ST848 (CC92) was the dominant strain isolated in both June and November. All isolates were blaOXA-51-like-positive, with 16 having ISAba1 upstream of the blaOXA-51-like and blaOXA-23-like genes. Genes such as blaNDM-1 (23 %, n=4), blaPER-7 (58.8 %, n=10), pkf (82 %, n=14), blaTEM-1 (5.8 %, n=1), cpa1 (5.8 %, n=1) and cpa2 (5.8 %, n=1) were also detected. CONCLUSION: M13 PCR can be used in routine environmental surveillance for the detection of persistent antibiotic resistant clones in an ICU setting because of its reliability and simplicity. Further studies based on greater sample size, conducted at the multi-centre level, can give us a better understanding of the reliability of the molecular methods that can be used for the detection of persistent clones in the hospital setting.


Assuntos
Infecções por Acinetobacter/microbiologia , Acinetobacter baumannii/isolamento & purificação , Biologia Molecular/métodos , Infecções por Acinetobacter/diagnóstico , Acinetobacter baumannii/classificação , Acinetobacter baumannii/efeitos dos fármacos , Acinetobacter baumannii/genética , Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Impressões Digitais de DNA/métodos , Farmacorresistência Bacteriana Múltipla , Humanos , Índia , Unidades de Terapia Intensiva/estatística & dados numéricos , Testes de Sensibilidade Microbiana , Tipagem de Sequências Multilocus/métodos , Reação em Cadeia da Polimerase/métodos , beta-Lactamases/genética , beta-Lactamases/metabolismo
19.
J Glob Antimicrob Resist ; 12: 155-156, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29410025

RESUMO

OBJECTIVES: Acinetobacter baumannii is a nosocomial pathogen responsible for various infections, including bloodstream infections, meningitis and ventilator-associated pneumonia. It is resistant to most antimicrobial agents, including colistin, and the development of colistin-resistant A. baumannii is of serious concern in the hospital setting. In this study, the whole-genome shotgun sequences of seven colistin-resistant A. baumannii isolates from bloodstream infections were characterised. METHODS: Colistin susceptibility testing was performed by broth microdilution. Whole genomes of all seven isolates were sequenced using an Ion Torrent™ PGM platform with 400-bp chemistry. RESULTS: All seven isolates were confirmed to be resistant to colistin, with minimum inhibitory concentrations (MICs) ranging from 8µg/mL to 64µg/mL. Various antimicrobial resistance genes were present. The mcr1-5 genes were absent in all seven isolates. Chromosomal mutations that could be responsible for colistin resistance were observed. Six isolates belonged to ST848 and one isolate belonged to ST451. CONCLUSION: Increased colistin resistance among clinical isolates of A. baumannii is alarming. Several mutations that could be responsible for colistin resistance were observed in all seven isolates. However, the significant contribution of these mutations requires further confirmation. However, genome information for these colistin-resistant A. baumannii isolates will be helpful for further comparative analysis.


Assuntos
Infecções por Acinetobacter/microbiologia , Acinetobacter baumannii/efeitos dos fármacos , Acinetobacter baumannii/genética , Antibacterianos/farmacologia , Bacteriemia/microbiologia , Colistina/farmacologia , Genoma Bacteriano , Acinetobacter baumannii/classificação , Acinetobacter baumannii/isolamento & purificação , Farmacorresistência Bacteriana , Humanos , Testes de Sensibilidade Microbiana
20.
Genome Announc ; 4(4)2016 Aug 11.
Artigo em Inglês | MEDLINE | ID: mdl-27516521

RESUMO

Acinetobacter baumannii is an important emerging pathogen that causes health care-associated infections. In this study, we determined the genome of a multidrug-resistant clinical strain, VB22595, isolated from a hospital in Southern India. The draft genome indicates that strain VB22595 encodes a genome of ~3.92 Mb in size and does not contain plasmid derived MCR-1 for colistin resistance.

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