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1.
Electron. j. biotechnol ; 46: 8-13, jul. 2020. tab, graf
Article in English | LILACS | ID: biblio-1223212

ABSTRACT

BACKGROUND: Poly-3-hydroxybutyrate (PHB) can be efficiently produced in recombinant Escherichia coli by the overexpression of an operon (NphaCAB) encoding PHB synthetase. Strain improvement is considered to be one of critical factors to lower the production cost of PHB in recombinant system. In this study, one of key regulators that affect the cell growth and PHB content was confirmed and analyzed. RESULT: S17-3, a mutant E. coli strain derived from S17-1, was found to be able to achieve high cell density when expressing NphaCAB with the plasmid pBhya-CAB. Whole genome sequencing of S17-3 revealed genetic alternations on the upstream regions of csrA, encoding a global regulator cross-talking between stress response, catabolite repression and other metabolic activities. Deletion of csrA or expression of mutant csrA resulted in improved cell density and PHB content. CONCLUSION: The impact of gene deletion of csrA was determined, dysfunction of the regulators improved the cell density of recombinant E. coli and PHB production, however, the detail mechanism needs to be further clarified.


Subject(s)
Escherichia coli/metabolism , Hydroxybutyrates/metabolism , Repressor Proteins/genetics , Biopolymers/genetics , Recombinant Proteins , RNA-Binding Proteins/genetics , Gene Deletion , Escherichia coli Proteins/genetics , Escherichia coli/genetics , Metabolic Engineering , Ligases/metabolism
2.
Mem. Inst. Oswaldo Cruz ; 115: e190469, 2020. graf
Article in English | SES-SP, LILACS, SES-SP | ID: biblio-1135243

ABSTRACT

BACKGROUND Oxidative stress is responsible for generating DNA lesions and the 8-oxoguanine (8-oxoG) is the most commonly lesion found in DNA damage. When this base is incorporated during DNA replication, it could generate double-strand DNA breaks and cellular death. MutT enzyme hydrolyzes the 8-oxoG from the nucleotide pool, preventing its incorporation during DNA replication. OBJECTIVES To investigate the importance of 8-oxoG in Leishmania infantum and L. braziliensis, in this study we analysed the impact of heterologous expression of Escherichia coli MutT (EcMutT) enzyme in drug-resistance phenotype and defense against oxidative stress. METHODS Comparative analysis of L. braziliensis and L. infantum H2O2 tolerance and cell cycle profile were performed. Lines of L. braziliensis and L. infantum expressing EcMutT were generated and evaluated using susceptibility tests to H2O2 and SbIII, cell cycle analysis, γH2A western blotting, and BrdU native detection assay. FINDINGS Comparative analysis of tolerance to oxidative stress generated by H2O2 showed that L. infantum is more tolerant to exogenous H2O2 than L. braziliensis. In addition, cell cycle analysis showed that L. infantum, after treatment with H2O2, remains in G1 phase, returning to its normal growth rate after 72 h. In contrast, after treatment with H2O2, L. braziliensis parasites continue to move to the next stages of the cell cycle. Expression of the E. coli MutT gene in L. braziliensis and L. infantum does not interfere in parasite growth or in susceptibility to SbIII. Interestingly, we observed that L. braziliensis EcMutT-expressing clones were more tolerant to H2O2 treatment, presented lower activation of γH2A, a biomarker of genotoxic stress, and lower replication stress than its parental non-transfected parasites. In contrast, the EcMutT is not involved in protection against oxidative stress generated by H2O2 in L. infantum. MAIN CONCLUSIONS Our results showed that 8-oxoG clearance in L. braziliensis is important to avoid misincorporation during DNA replication after oxidative stress generated by H2O2.


Subject(s)
Humans , Animals , Mice , Rats , Pyrophosphatases/genetics , Pyrophosphatases/metabolism , Superoxide Dismutase/metabolism , Leishmania braziliensis/drug effects , Leishmania infantum/drug effects , Escherichia coli Proteins/genetics , Escherichia coli , Guanine/analogs & derivatives , Antimony/toxicity , Rabbits , Superoxide Dismutase/genetics , Leishmania braziliensis/enzymology , Leishmania infantum/enzymology , Oxidative Stress/drug effects , Oxidative Stress/physiology , Escherichia coli Proteins/metabolism , Guanine/pharmacology , Hydrogen Peroxide/toxicity , Antiprotozoal Agents/pharmacology
3.
Chinese Journal of Biotechnology ; (12): 2104-2112, 2020.
Article in Chinese | WPRIM | ID: wpr-878470

ABSTRACT

Shikimic acid is an intermediate metabolite in the synthesis of aromatic amino acids in Escherichia coli and a synthetic precursor of Tamiflu. The biosynthesis of shikimic acid requires blocking the downstream shikimic acid consuming pathway that leads to inefficient production and cell growth inhibition. In this study, a dynamic molecular switch was constructed by using growth phase-dependent promoters and degrons. This dynamic molecular switch was used to uncouple cell growth from shikimic acid synthesis, resulting in the production of 14.33 g/L shikimic acid after 72 h fermentation. These results show that the dynamic molecular switch could redirect the carbon flux by regulating the abundance of target enzymes, for better production.


Subject(s)
Escherichia coli/genetics , Escherichia coli Proteins/genetics , Industrial Microbiology/methods , Metabolic Engineering , Shikimic Acid/metabolism
4.
Braz. j. infect. dis ; 23(3): 203-206, May-June 2019. graf
Article in English | LILACS | ID: biblio-1039226

ABSTRACT

ABSTRACT Global dissemination of mcr-like genes represents a serious threat to public health since it jeopardizes the effectiveness of colistin, an antibiotic used as a last-resort treatment against highly antibiotic-resistant bacteria. In 2017, a mcr-1-positive isolate of Escherichia coli was found in Chile for the first time. Herein we report the genetic features of this strain (UCO-457) by whole-genome sequencing (WGS) and conjugation experiments. The UCO-457 strain belonged to ST4204 and carried a 285 kb IncI2-type plasmid containing the mcr-1 gene. Moreover, this plasmid was transferred by conjugation to an E. coli J53 strain at high frequency. The isolate harbored the cma, iroN, and iss virulence genes and did carry resistance genes to trimethoprim/sulfamethoxazole and fluoroquinolones. Other antibiotic resistance determinants such as β-lactamases-encoding genes were not detected, making the isolate highly susceptible to these antibiotics. Our results revealed that such susceptible isolates could be acting as platforms to disseminate plasmid-mediated colistin resistance. Based on this evidence, we consider that mcr-like prevalence deserves urgent attention and should be examined not only in highly resistant bacteria but also in susceptible isolates.


Subject(s)
Humans , Escherichia coli Proteins/genetics , Escherichia coli/genetics , Escherichia coli Infections/microbiology , Outpatients , Chile , Escherichia coli/drug effects , Disk Diffusion Antimicrobial Tests , Anti-Bacterial Agents/pharmacology
5.
Braz. j. microbiol ; 49(4): 936-941, Oct.-Dec. 2018. tab, graf
Article in English | LILACS | ID: biblio-1039269

ABSTRACT

ABSTRACT Shigatoxigenic and enteropathogenic Escherichia coli with virulence and multidrug resistance profile were isolated from Nile tilapia. This study finding is of great importance to public health because they help understand this pathogen epidemiology in fish and demonstrate how these animals can transmit E. coli related diseases to humans.


Subject(s)
Humans , Animals , Enteropathogenic Escherichia coli/isolation & purification , Shiga-Toxigenic Escherichia coli/isolation & purification , Fishes/microbiology , Phylogeny , Food Contamination/analysis , Consumer Product Safety , Escherichia coli Proteins/genetics , Enteropathogenic Escherichia coli/classification , Enteropathogenic Escherichia coli/genetics , Shiga-Toxigenic Escherichia coli/classification , Shiga-Toxigenic Escherichia coli/genetics , Meat/microbiology
6.
Braz. j. microbiol ; 49(3): 569-574, July-Sept. 2018. tab, graf
Article in English | LILACS | ID: biblio-951794

ABSTRACT

Abstract Multidrug-resistant microorganisms are of great concern to public health. Genetic mobile elements, such as plasmids, are among the most relevant mechanisms by which bacteria achieve this resistance. We obtained an Escherichia coli strain CM6, isolated from cattle presenting severe diarrheic symptoms in the State of Querétaro, Mexico. It was found to contain a 70 kb plasmid (pMEX01) with a high similarity to the pHK01-like plasmids that were previously identified and described in Hong Kong. Analysis of the pMEX01 sequence revealed the presence of a blaCTX-M-14 gene, which is responsible for conferring resistance to multiple β-lactam antibiotics. Several genes putatively involved in the conjugative transfer were also identified on the plasmid. The strain CM6 is of high epidemiological concern because it not only displays resistance to multiple β-lactam antibiotics but also to other kinds of antibiotics.


Subject(s)
Animals , Cattle , Plasmids/genetics , Cattle Diseases/microbiology , Drug Resistance, Bacterial , beta-Lactams/pharmacology , Escherichia coli/drug effects , Escherichia coli/genetics , Escherichia coli Infections/veterinary , Anti-Bacterial Agents/pharmacology , Plasmids/metabolism , beta-Lactamases/genetics , beta-Lactamases/metabolism , Microbial Sensitivity Tests , Escherichia coli Proteins/genetics , Escherichia coli Proteins/metabolism , Escherichia coli/metabolism , Escherichia coli Infections/microbiology , Mexico
7.
Braz. j. microbiol ; 49(3): 471-480, July-Sept. 2018. tab, graf
Article in English | LILACS | ID: biblio-951821

ABSTRACT

Abstract Escalating burden of antibiotic resistance that has reached new heights present a grave concern to mankind. As the problem is no longer confined to clinics, we hereby report identification of a pandrug resistant Escherichia coli isolate from heavily polluted Delhi stretch of river Yamuna, India. E. coli MRC11 was found sensitive only to tobramycin against 21 antibiotics tested, with minimum inhibitory concentration values >256 µg/mL for amoxicillin, carbenicillin, aztreonam, ceftazidime and cefotaxime. Addition of certain heavy metals at higher concentrations were ineffective in increasing susceptibility of E. coli MRC11 to antibiotics. Withstanding sub-optimal concentration of cefotaxime (10 µg/mL) and mercuric chloride (2 µg/mL), and also resistance to their combinatorial use, indicates better adaptability in heavily polluted environment through clustering and expression of resistance genes. Interestingly, E. coli MRC11 harbours two different variants of blaTEM (blaTEM-116 and blaTEM-1 with and without extended-spectrum activity, respectively), in addition to mer operon (merB, merP and merT) genes. Studies employing conjugation, confirmed localization of blaTEM-116, merP and merT genes on the conjugative plasmid. Understanding potentialities of such isolates will help in determining risk factors attributing pandrug resistance and strengthening strategic development of new and effective antimicrobial agents.


Subject(s)
Metals, Heavy/pharmacology , Drug Resistance, Multiple, Bacterial , Rivers/microbiology , Escherichia coli/drug effects , Anti-Bacterial Agents/pharmacology , Operon , beta-Lactamases/genetics , beta-Lactamases/metabolism , Microbial Sensitivity Tests , Escherichia coli Proteins/genetics , Escherichia coli Proteins/metabolism , Escherichia coli/isolation & purification , Escherichia coli/enzymology , Escherichia coli/genetics , India
8.
Braz. j. microbiol ; 49(supl.1): 107-112, 2018. tab, graf
Article in English | LILACS | ID: biblio-1039271

ABSTRACT

Abstract Avian pathogenic Escherichia coli (APEC) isolates from apparently healthy free range helmeted guineafowl were characterized. Most of them had a high frequency of virulence associated genes, multi drug resistance and high pathogenicity. We demonstrated that helmeted guineafowl have potential to transmit antibiotic resistant APEC to other species including humans.


Subject(s)
Animals , Bird Diseases/microbiology , Escherichia coli/isolation & purification , Escherichia coli Infections/veterinary , Escherichia coli Proteins/genetics , Escherichia coli Proteins/metabolism , Drug Resistance, Bacterial , Virulence Factors/genetics , Virulence Factors/metabolism , Galliformes/microbiology , Escherichia coli/classification , Escherichia coli/drug effects , Escherichia coli/genetics , Escherichia coli Infections/microbiology , Anti-Bacterial Agents/pharmacology
9.
Braz. j. microbiol ; 48(4): 760-763, Oct.-Dec. 2017. tab
Article in English | LILACS | ID: biblio-889158

ABSTRACT

ABSTRACT Psittacine birds have been identified as reservoirs of diarrheagenic Escherichia coli, a subset of pathogens associated with mortality of children in tropical countries. The role of other orders of birds as source of infection is unclear. The aim of this study was to perform the molecular diagnosis of infection with diarrheagenic E. coli in 10 different orders of captive wild birds in the state of São Paulo, Brazil. Fecal samples were analyzed from 516 birds belonging to 10 orders: Accipitriformes, Anseriformes, Columbiformes, Falconiformes, Galliformes, Passeriformes, Pelecaniformes, Piciformes, Psittaciformes and Strigiformes. After isolation, 401 E. coli strains were subjected to multiplex PCR system with amplification of genes eae and bfp (EPEC), stx1 and stx2 for STEC. The results of these tests revealed 23/401 (5.74%) positive strains for eae gene, 16/401 positive strains for the bfp gene (3.99%) and 3/401 positive for stx2 gene (0.75%) distributed among the orders of Psittaciformes, Strigiformes and Columbiformes. None of strains were positive for stx1 gene. These data reveal the infection by STEC, typical and atypical EPEC in captive birds. The frequency of these pathotypes is low and restricted to few orders, but the data suggest the potential public health risk that these birds represent as reservoirs of diarrheagenic E. coli.


Subject(s)
Animals , Birds/microbiology , Disease Reservoirs/microbiology , Enteropathogenic Escherichia coli/isolation & purification , Shiga-Toxigenic Escherichia coli/isolation & purification , Animals, Wild/microbiology , Birds/classification , Brazil , Escherichia coli Proteins/genetics , Escherichia coli Proteins/metabolism , Enteropathogenic Escherichia coli/classification , Enteropathogenic Escherichia coli/genetics , Enteropathogenic Escherichia coli/metabolism , Shiga-Toxigenic Escherichia coli/classification , Shiga-Toxigenic Escherichia coli/genetics , Shiga-Toxigenic Escherichia coli/metabolism , Animals, Wild/classification
10.
Clinics ; 72(10): 642-644, Oct. 2017.
Article in English | LILACS | ID: biblio-1039534

ABSTRACT

OBJECTIVE: We describe an IncX4 pHC891/16mcr plasmid carrying mcr-1 in a colistin-resistant and carbapenem-susceptible E. coli isolate (HC891/16), ST156, which caused a blood infection in a Brazilian patient with gallbladder adenocarcinoma. METHODS: Strain HC891/16 was subjected to whole genome sequencing using the MiSeq Platform (Illumina, Inc., USA). Assembly was performed using Mira and ABACAS. RESULTS: The isolates showed resistance only to ciprofloxacin, ampicillin and cefoxitin, and whole-genome sequencing revealed the presence of aac(6')Ib-cr and blaTEM1. CONCLUSION: Our findings warn of the possible silent dissemination of colistin resistance by carbapenem-susceptible mcr-1 producers, as colistin susceptibility is commonly tested only among carbapenem-resistant isolates.


Subject(s)
Humans , Female , Aged , Carbapenems/pharmacology , Bacteremia/drug therapy , Colistin/pharmacology , Escherichia coli Proteins/drug effects , Escherichia coli/drug effects , Anti-Bacterial Agents/pharmacology , Plasmids/drug effects , Brazil , Microbial Sensitivity Tests , Escherichia coli Proteins/isolation & purification , Escherichia coli Proteins/genetics , Drug Resistance, Multiple, Bacterial , Escherichia coli/isolation & purification , Escherichia coli/genetics , Escherichia coli Infections/drug therapy
11.
Rev. Soc. Bras. Med. Trop ; 50(3): 315-320, May-June 2017. tab
Article in English | LILACS | ID: biblio-896964

ABSTRACT

Abstract INTRODUCTION: Pseudomonas aeruginosa is one of the most common nosocomial pathogens. The emergence of extended spectrum β-lactamases (ESBLs) has been increasingly reported as a major clinical concern worldwide. The main aim of the present study was to determine the distribution of bla OXA, bla PER-1, bla VEB-1, and bla GES-1 genes among ESBL-producing P. aeruginosa isolated from two distinct provinces in Iran. METHODS: In this study, a total of 75 (27.5%) ESBL-producing isolates were identified from 273 P. aeruginosa isolates collected from patients in Qazvin and Tehran. Phenotypic detection of ESBLs and antimicrobial susceptibility testing were performed according to the Clinical and Laboratory Standards Institute guidelines. PCR and sequencing were employed to detect bla OXA-1, bla OXA, bla GES-1, bla PER-1, and bla VEB-1 genes. Isolate genetic relationships were evaluated by repetitive extragenic palindromic sequence-based PCR (REP-PCR). RESULTS: In total, 59 (78.7%) of the ESBL-producing isolates showed multidrug resistance. The highest rates of susceptibility were observed against colistin (75 isolates, 100%) and polymyxin B (75, 100%) followed by amikacin (44, 58.7%), and piperacillin-tazobactam (40, 53.3%). The bla OXA-1 (37.3%) gene was the most common of the genes investigated, followed by bla OXA-4 (32%), bla GES-1 (16%), and bla VEB-1 (13.3%). REP-PCR identified three different genotypes: types A (89.3%), B (6.7%), and C (4%). CONCLUSIONS: We found a significant presence of bla OXA-1, bla OXA-4, bla GES-1, and bla VEB-1 genes among P. aeruginosa isolates, highlighting the need for suitable infection control strategies to effectively treat patients and prevent the further distribution of these resistant organisms.


Subject(s)
Humans , Male , Female , Pseudomonas aeruginosa/genetics , beta-Lactamases/genetics , Drug Resistance, Multiple, Bacterial/genetics , Anti-Bacterial Agents/pharmacology , Pseudomonas aeruginosa/drug effects , Pseudomonas aeruginosa/enzymology , Microbial Sensitivity Tests , Polymerase Chain Reaction , Escherichia coli Proteins/genetics , Genes, Bacterial , Genotype , Iran
12.
Braz. j. microbiol ; 47(2): 414-416, Apr.-June 2016. graf
Article in English | LILACS | ID: lil-780834

ABSTRACT

Abstract Escherichia coli is the major causative agent of human cystitis. In this study, a preliminary molecular analysis carried out by PCR (polymerase chain reaction) demonstrated that 100% of 31 E. coli strains isolated from patients with recurrent UTIs (urinary tract infections) showed the presence of the curli fimbria gene (csgA). Curli fimbria is known to be associated with bacterial biofilm formation but not with the adhesion of human cystitis-associated E. coli. Therefore, this work aimed to study how curli fimbria is associated with uropathogenic E. coli (UPEC) as an adhesion factor. For this purpose, the csgA gene was deleted from strain UPEC-4, which carries three adhesion factor genes (csgA, fimH and ompA). The wild-type UPEC-4 strain and its mutant (ΔcsgA) were analyzed for their adhesion ability over HTB-9 (human bladder carcinoma), Vero (kidney cells of African green monkey) and HUVEC (human umbilical vein) cells in the presence of α-D-mannose. All the wild-type UPEC strains tested (100%) were able to adhere to all three cell types, while the UPEC-4 ΔcsgA mutant lost its adherence to HTB-9 but continued to adhere to the HUVEC and Vero cells. The results suggest that curli fimbria has an important role in the adhesion processes associated with human UPEC-induced cystitis.


Subject(s)
Humans , Adhesins, Escherichia coli/metabolism , Cystitis/microbiology , Escherichia coli Proteins/metabolism , Escherichia coli Infections/microbiology , Uropathogenic Escherichia coli/metabolism , Bacterial Adhesion , Gene Expression Regulation, Bacterial , Sequence Deletion , Adhesins, Escherichia coli/genetics , Escherichia coli Proteins/genetics , Uropathogenic Escherichia coli/genetics
13.
Braz. j. microbiol ; 47(2): 337-344, Apr.-June 2016. tab, graf
Article in English | LILACS | ID: lil-780846

ABSTRACT

Abstract Fecal bacteria are considered to be a potential reservoir of antimicrobial resistance genes in the aquatic environment and could horizontally transfer these genes to autochthonous bacteria when carried on transferable and/or mobile genetic elements. Such circulation of resistance genes constitutes a latent public health hazard. The aim of this study was to characterize the variable region of the class 1 integron and relate its genetic content to resistance patterns observed in antimicrobial-resistant Escherichia coli isolated from the surface waters of Patos Lagoon, Southern Brazil. Genetic diversity of the isolates and presence of the qacEΔ1 gene, which confers resistance to quaternary ammonium compounds, were also investigated. A total of 27 isolates were analyzed. The variable region harbored dfrA17, dfrA1 and dfrA12 genes, which confer resistance to trimethoprim, and aadA1, aadA5 and aadA22 genes that encode resistance to streptomycin/spectinomycin. Most of the isolates were considered resistant to quaternary ammonium compounds and all of them carried the qacE Δ1 gene at the 3′ conserved segment of the integron. ERIC-PCR analyses of E. coli isolates that presented the integrons showed great genetic diversity, indicating diverse sources of contamination in this environment. These results suggest that fecal bacteria with class 1 integrons in aquatic environments are potentially important reservoirs of antibiotic-resistance genes and may transfer these elements to other bacteria that are capable of infecting humans.


Subject(s)
Integrons , Escherichia coli/isolation & purification , Escherichia coli/genetics , Fresh Water/microbiology , Anti-Bacterial Agents/pharmacology , Phylogeny , Genetic Variation , Brazil , Escherichia coli Proteins/genetics , Escherichia coli Proteins/metabolism , Escherichia coli/drug effects , Escherichia coli/metabolism
14.
Mem. Inst. Oswaldo Cruz ; 111(5): 349-354, May 2016. graf
Article in English | LILACS | ID: lil-782047

ABSTRACT

During its life cycle Leishmania spp. face several stress conditions that can cause DNA damages. Base Excision Repair plays an important role in DNA maintenance and it is one of the most conserved mechanisms in all living organisms. DNA repair in trypanosomatids has been reported only for Old World Leishmania species. Here the AP endonuclease from Leishmania (L.) amazonensis was cloned, expressed in Escherichia coli mutants defective on the DNA repair machinery, that were submitted to different stress conditions, showing ability to survive in comparison to the triple null mutant parental strain BW535. Phylogenetic and multiple sequence analyses also confirmed that LAMAP belongs to the AP endonuclease class of proteins.


Subject(s)
DNA Damage/genetics , DNA Repair/genetics , DNA-(Apurinic or Apyrimidinic Site) Lyase/genetics , Escherichia coli/genetics , Leishmania braziliensis/genetics , Mutation/genetics , Amino Acid Sequence , Escherichia coli Proteins/genetics , Escherichia coli/enzymology , Molecular Sequence Data
15.
Braz. j. microbiol ; 46(3): 875-878, July-Sept. 2015. tab, ilus
Article in English | LILACS | ID: lil-755809

ABSTRACT

The invasin gimB (genetic island associated with human newborn meningitis) is usually found in ExPEC (Extraintestinal Pathogenic Escherichia coli) such as UPEC (uropathogenic E. coli), NMEC (neonatal meningitis E. coli) and APEC (avian pathogenic E. coli). In NMEC, gimB is associated with the invasion process of the host cells. Due to the importance of E. coli as a zoonotic agent and the scarce information about the frequency of gimB-carrying strains in different animal species, the aim of this study was to investigate the presence of gimB in isolates from bovine, swine, canine and feline clinical samples. PCR was conducted on 196 isolates and the identity of the amplicons was confirmed by sequencing. Of the samples tested, only E. coli SB278/94 from a bovine specimen was positive (1/47) for gimB, which represents 2.1% of the bovine isolates. The ability of SB278/94 to adhere to and invade eukaryotic cells was confirmed by adherence and gentamicin-protection assays using HeLa cells. This is the first study that investigates for gimB in bovine, canine and feline E. coli isolates and shows E. coli from the intestinal-bovine samples harboring gimB.

.


Subject(s)
Animals , Cats , Cattle , Dogs , Humans , Bacterial Adhesion/genetics , Cat Diseases/microbiology , Cattle Diseases/microbiology , Dog Diseases/microbiology , Escherichia coli Proteins/genetics , Escherichia coli/pathogenicity , Intestines/microbiology , Swine Diseases/microbiology , Virulence Factors/genetics , Base Sequence , Cell Line, Tumor , Escherichia coli Infections/microbiology , Escherichia coli/genetics , Escherichia coli/isolation & purification , Genes, Bacterial , Gentamicins/pharmacology , HeLa Cells , Polymerase Chain Reaction , Sequence Analysis, DNA , Swine
16.
Rev. argent. microbiol ; 47(2): 88-94, June 2015. tab
Article in Spanish | LILACS | ID: lil-757146

ABSTRACT

En la provincia del Chaco, el agua subterránea representa una fuente alternativa, y muchas veces única, para el consumo humano; esta es utilizada en el 14 % de los hogares. A pesar de que se reconoce el riesgo de la exposición al agua contaminada, la prevalencia de los diferentes patotipos de Escherichia coli en ambientes acuáticos no ha sido bien caracterizada. E. coli enteroagregativo (ECEA) es un patógeno emergente cuya importancia en la salud pública mundial se incrementó y quedó claramente establecida en los últimos años. El objetivo del presente trabajo fue detectar la presencia de ECEA típico mediante el reconocimiento de los factores de virulencia aap, AA probe y aggR por reacción en cadena de la polimerasa, en fuentes de agua subterráneas de la provincia del Chaco. Se identificó E. coli en 36 (38,7 %) de las 93 muestras estudiadas, provenientes de diferentes localidades. De esos 36 aislamientos, se identificaron 6 (16,7 %) portadores de los genes de ECEA, lo que representa una prevalencia del 6,4 % considerando las 93 fuentes de agua subterránea estudiadas. De esos 6 aislamientos, 3 eran portadores del gen aap, 2 del gen AA probe y uno de la combinación aggR/aap. El presente trabajo representa el primer aporte en el estudio de la presencia y distribución de genes de virulencia de ECEA en fuentes de agua subterránea de la región.


Groundwater is an important source of drinking water for many communities in Northern Argentina; particularly, in the province of Chaco, where about 14 % of households use this natural resource. Enteroaggregative Escherichia coli is an emerging pathogen whose global importance in public health has increased in recent years. Despite the significant risk of disease linked to contaminated water exposure, the prevalence of E. coli pathotypes in aquatic environments is still not so well defined. The aim of the present study was to detect the presence of typical enteroaggregative E. coli through the recognition of its virulence factors aap, AA probe and aggR by molecular techniques. A total of 93 water samples from different small communities of Chaco were analyzed. E. coli was identified in 36 (38.7 %) of the tested samples. Six strains isolated from different samples harbored the studied genes. Of these 6 isolates, 3 carried the aap gene, 2 the AA probe and the last one the combination of aap/aggR genes. The prevalence of E. coli isolates harboring enteroaggregative virulence genes in groundwater sources was 6.4 %. This work represents the first contribution to the study of the presence and distribution of virulence genes of EAEC in groundwater sources in this region of Argentina.


Subject(s)
Escherichia coli Proteins/genetics , Escherichia coli/genetics , Genes, Bacterial , Groundwater/microbiology , Trans-Activators/genetics , Water Pollution , Argentina , Escherichia coli Proteins/physiology , Escherichia coli/isolation & purification , Escherichia coli/pathogenicity , Trans-Activators/physiology , Virulence/genetics , Water Supply
17.
Rev. argent. microbiol ; 47(2): 95-102, June 2015. tab
Article in English | LILACS | ID: lil-757147

ABSTRACT

The aim of this study was to perform a current molecular characterization of bovine pathogenic Escherichia coli strains isolated from random samplings in Argentinean dairy farms. Rectal swabs were obtained from 395 (63.7 %) healthy and 225 (36.3 %) diarrheic calves, belonging to 45 dairy farms in Cordoba Province, Argentina. E. coli isolates were examined for virulence genes (f5, f41, f17, sta, stb, lt, eae, vt) using PCR and the prevalence of E. coli virulence profiles was spatially described in terms of spatial distribution. A total of 30.1 % isolates were found to be positive for at least one of the virulence genes. Depending on the different gene combinations present, 11 virulence profiles were found. Most of the isolates analyzed had a single gene, and no combination of fimbrial and enterotoxin gene was predominant. There was no association between the frequency and distribution of E. coli virulence genes and calf health status. Most of the virulence profiles were compatible with ETEC strains and showed a homogeneous distribution over the sampled area. A clustering pattern for E. coli virulence profiles could not be recognized. This work provides updated information on the molecular characterization of pathogenic E. coli strains from dairy herds in Cordoba, Argentina. These findings would be important to formulate prevention programs and effective therapies for diarrhea in calves caused by E. coli.


El objetivo de este trabajo fue realizar una caracterización molecular actualizada de cepas patógenas bovinas de Escherichia coli aisladas de un muestreo aleatorio en tambos de una de las principales zonas lecheras de Argentina. Se obtuvieron hisopados rectales de 395 terneros neonatos sanos (63,7 %) y 225 diarreicos (36,3 %) pertenecientes a 45 tambos de la provincia de Córdoba, Argentina. Los genes de virulencia f5, f41, f17, sta, stb, lt, eae y vt se analizaron mediante PCR y se investigó la prevalencia de los perfiles de virulencia en función de la distribución geográfica. La prevalencia de aislamientos de E. coli patogénicos con al menos un gen de virulencia fue del 30,1 %. Once perfiles de virulencia fueron identificados, dependiendo de la combinación de genes presentes. La mayor parte de las muestras presentó un solo gen de virulencia, y no predominó ninguna combinación de genes de fimbrias y toxinas. No hubo asociación entre la frecuencia y la distribución de los genes de virulencia y el estado de salud de los terneros. La mayoría de los perfiles de virulencia fueron compatibles con cepas ECET y se distribuyeron cubriendo toda el área geográfica muestreada. No se reconoció ningún patrón de agrupamiento espacial para dichos perfiles. Este trabajo provee información actualizada sobre la caracterización molecular de E. coli patógena en rodeos lecheros de Córdoba, Argentina. Estos resultados serían importantes para formular programas preventivos y terapias eficaces contra la diarrea bovina causada por E. coli.


Subject(s)
Animals , Animals, Newborn/microbiology , Cattle Diseases/epidemiology , Cattle/microbiology , Diarrhea/veterinary , Escherichia coli Infections/veterinary , Escherichia coli/isolation & purification , Genes, Bacterial , Argentina/epidemiology , Cattle Diseases/microbiology , Dairying , Diarrhea/epidemiology , Diarrhea/microbiology , Enterotoxins/genetics , Escherichia coli Infections/epidemiology , Escherichia coli Infections/microbiology , Escherichia coli Proteins/genetics , Escherichia coli/genetics , Escherichia coli/pathogenicity , Fimbriae, Bacterial/genetics , Prevalence , Sampling Studies , Virulence/genetics
18.
Dental press j. orthod. (Impr.) ; 20(2): 29-34, Mar-Apr/2015. tab, graf
Article in English | LILACS | ID: lil-745854

ABSTRACT

OBJECTIVE: The purpose of this study was to assess the influence of magnification and superimposition of structures on CBCT-generated lateral cephalometric radiographs (LCR) using different segments of the cranium. METHODS: CBCT scans of 10 patients were selected. Four LCR were generated using Dolphin Imaging(r) software: full-face, right side, left side and center of the head. A total of 40 images were imported into Radiocef Studio 2(r), and the angles of the most common cephalometric analyses were traced by the same observer twice and within a 10-day interval. Statistical analyses included intraexaminer agreement and comparison between methods by means of intraclass correlation coefficient (ICC) and Bland-Altman agreement tests. RESULTS: Intraexaminer agreement of the angles assessed by ICC was excellent (> 0.90) for 83% of measurements, good (between 0.75 and 0.90) for 15%, and moderate (between 0.50 and 0.75) for 2% of measurements. The comparison between methods by ICC was excellent for 68% of measurements, good for 26%, and moderate for 6%. Variables presenting wider confidence intervals (> 6o) in the Bland-Altman tests, in intraexaminer assessment, were: mandibular incisor angle, maxillary incisor angle, and occlusal plane angle. And in comparison methods the variables with wider confidence interval were: mandibular incisor, maxillary incisor, GoGn, occlusal plane angle, Frankfort horizontal plane (FHP), and CoA. CONCLUSION: Superimposition of structures seemed to influence the results more than magnification, and neither one of them significantly influenced the measurements. Considerable individual variability may occur, especially for mandibular and maxillary incisors, FHP and occlusal plane. .


OBJETIVO: o objetivo do presente estudo foi avaliar a influência da sobreposição estrutural e da magnificação nas radiografias cefalométricas laterais (RCL) geradas por meio de tomografias computadorizadas de feixe cônico (TCFC), usando diferentes segmentos do crânio. MÉTODOS: foram selecionadas 10 tomografias de pacientes. Quatro RCL foram geradas usando Dolphin Imaging, sendo face total, lado direito, lado esquerdo e o centro da cabeça. Um total de 40 imagens foi importado para o Radiocef Studio, e os ângulos das análises cefalométricas mais comuns foram medidos pelo mesmo observador, duas vezes, em um intervalo de 10 dias. As análises estatísticas incluíram concordância intraexaminador e comparação entre os métodos por meio do coeficiente de correlação intraclasse (ICC) e testes de concordância de Bland-Altman. RESULTADOS: a concordância intraexaminador dos ângulos avaliados pelo ICC foi excelente (> 0,90) para 83% das medições, boa (entre 0,75 e 0,90) para 15%, e moderada (entre 0,50 e 0,75) para 2% das medições. A comparação entre os métodos por ICC foi excelente para 68% das medições, boa para 26% e moderada para 6%. As variáveis que apresentaram intervalos de confiança mais amplos (> 6°) nos testes de Bland-Altman, na avaliação intraexaminador, foram: incisivo superior, incisivo inferior e plano oclusal, enquanto nos métodos de comparação, as variáveis com intervalos de confiança mais amplos foram: incisivo inferior, incisivo superior, GoGn, ângulo do plano oclusal, plano horizontal de Frankfort e CoA. CONCLUSÃO: a sobreposição estrutural pareceu influenciar os resultados mais do que a magnificação, mas os métodos não influenciaram significativamente as medições. Considerável variabilidade individual pode ocorrer especialmente para os incisivos superiores e inferiores, plano horizontal de Frankfort e plano oclusal. .


Subject(s)
DNA Repair , Deoxyguanosine/analogs & derivatives , Escherichia coli Proteins/genetics , Escherichia coli/genetics , Gene Expression Regulation, Bacterial , Mutagenesis/radiation effects , Sugar Acids/metabolism , Biological Assay , DNA Breaks, Double-Stranded , DNA Polymerase beta/genetics , DNA Polymerase beta/metabolism , Deoxyguanosine/chemistry , Deoxyguanosine/metabolism , Escherichia coli Proteins/metabolism , Escherichia coli/metabolism , Escherichia coli/radiation effects , Flap Endonucleases/genetics , Flap Endonucleases/metabolism , Furans/chemistry , Furans/metabolism , Gamma Rays , Mutation , Plasmids , Sugar Acids/chemistry
19.
Clinics ; 70(2): 144-151, 2/2015. tab, graf
Article in English | LILACS | ID: lil-741418

ABSTRACT

OBJECTIVE: To analyze steroidogenesis-related gene expression in the rat ovary exposed to melatonin supplementation. METHODS: Thirty-two virgin adult female rats were randomized to two groups as follows: the control group GI received vehicle and the experimental group GII received melatonin supplementation (10 µg/night per animal) for 60 consecutive days. After the treatment, animals were anesthetized and the collected ovaries were immediately placed in liquid nitrogen for complementary deoxyribonucleic acid microarray analyses. A GeneChip¯ Kit Rat Genome 230 2.0 Affymetrix Array was used for gene analysis and the experiment was repeated three times for each group. The results were normalized with the GeneChip¯ Operating Software program and confirmed through analysis with the secondary deoxyribonucleic acid-Chip Analyzer (dChip) software. The data were confirmed by real-time reverse transcription polymerase chain reaction analysis. Genes related to ovarian function were further confirmed by immunohistochemistry. RESULTS: We found the upregulation of the type 9 adenylate cyclase and inhibin beta B genes and the downregulation of the cyclic adenosine monophosphate response element modulator and cytochrome P450 family 17a1 genes in the ovarian tissue of GII compared to those of the control group. CONCLUSION: Our data suggest that melatonin supplementation decreases gene expression of cyclic adenosine monophosphate, which changes ovarian steroidogenesis. .


Subject(s)
Humans , Escherichia coli Infections/microbiology , Urinary Tract Infections/microbiology , Uropathogenic Escherichia coli/pathogenicity , Escherichia coli Proteins/genetics , India/epidemiology , Prevalence , Uropathogenic Escherichia coli/genetics
20.
Rev. argent. microbiol ; 46(3): 175-181, oct. 2014. tab
Article in Spanish | LILACS | ID: lil-734579

ABSTRACT

En este estudio se determinó el perfil de distribución de grupos filogéneticos y la detección genética de factores de virulencia en cepas de Escherichia coli uropatógena (ECUP) productoras de ß-lactamasa CTX-M-15. Veintiocho cepas fueron aisladas de pacientes con infección del tracto urinario (ITU) que asistieron al Laboratorio de Salud Pública del estado Mérida, Venezuela, durante el lapso comprendido entre enero 2009 y julio 2011. La determinación de los grupos filogenéticos y la detección de seis genes de virulencia, fimH, fyuA, kpsMTII, usp, PAI y papAH, se realizó mediante amplificación por PCR. Quince cepas de 28 se ubicaron principalmente en el filogrupo A, seguidos por el B2 (12/28) y D (1/28). No se observó una relación directa entre la recurrencia o gravedad de la ITU y la distribución de los filogrupos. Todos los factores de virulencia estudiados se encontraron con la frecuencia más alta en el grupo B2. El perfil de virulencia prevalente estuvo conformado por la asociación de tres genes principales: fimH, fyuA y kpsMTII y en menor frecuencia, por la presencia de otros determinantes como usp, PAI y/o papAH. Estos resultados indican que la mayoría de ECUP estuvieron dotadas de tres propiedades virulentas importantes: adhesión, captación de hierro y evasión de la fagocitosis, las cuales favorecieron la producción de ITU recurrentes. Este es el primer trabajo que describe la asociación de grupos filogenéticos con el potencial de virulencia de cepas de ECUP productoras de ß-lactamasa CTX-M-15 en Venezuela.


In this study, the distribution of phylogenetic groups and the genetic detection of virulence factors in CTX-M-15 ß-lactamase-producing uropathogenic Escherichia coli (UPEC) strains were analyzed. Twenty eight strains were isolated between January 2009 and July 2011 from patients with urinary tract infection (UTI) who attended the Public Health Laboratory at Mérida, Venezuela. Determination of phylogenetic groups and detection of six virulence genes, fimH, fyuA, kpsMTII, usp, PAI and papAH, were performed by PCR amplification. Fifteen of the 28 isolates were mainly located in the phylogenetic group A, followed by B2 (12/28) and D (1/28). No direct relationship between the severity or recurrence of UTI and the distribution of phylogroups was observed. All studied virulence factors were found in group B2 strains with the highest frequency. The prevalent virulence profile included the combination of three main genes: fimH, kpsMTII and fyuA and, to a lesser extent, the presence of other determinants such as usp, PAI and/or papAH. These results indicate that virulent UPEC incorporated three important properties: adhesion, iron uptake and evasion of phagocytosis, which favored the production of recurrent UTI. This is the first report describing the association of phylogenetic groups with the potential virulence of CTX-M-15 ß-lactamase producing UPEC strains in Venezuela.


Subject(s)
Adolescent , Adult , Aged , Aged, 80 and over , Child , Female , Humans , Male , Middle Aged , Pregnancy , Young Adult , Community-Acquired Infections/microbiology , Escherichia coli Infections/microbiology , Escherichia coli Proteins/analysis , Escherichia coli/classification , Urinary Tract Infections/microbiology , beta-Lactamases/analysis , Bacterial Adhesion/genetics , Comorbidity , Community-Acquired Infections/epidemiology , Disease Susceptibility , DNA, Bacterial/genetics , Escherichia coli Infections/epidemiology , Escherichia coli Proteins/genetics , Escherichia coli/enzymology , Escherichia coli/genetics , Escherichia coli/isolation & purification , Genes, Bacterial , Iron/metabolism , Phagocytosis , Phylogeny , Pregnancy Complications, Infectious/microbiology , Recurrence , Urinary Tract Infections/epidemiology , Venezuela/epidemiology , Virulence/genetics , beta-Lactamases/genetics
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