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1.
BMC Microbiol ; 24(1): 136, 2024 Apr 24.
Article in English | MEDLINE | ID: mdl-38658819

ABSTRACT

OBJECTIVES: In the recent years, multidrug resistant (MDR) neonatal septicemia-causing Enterobacterales has been dramatically increased due to the extended-spectrum beta-lactamases (ESBLs) and AmpC enzymes. This study aimed to assess the antibiotic resistance pattern, prevalence of ESBLs/AmpC beta-lactamase genes, and Enterobacterial Repetitive Intergenic Consensus Polymerase Chain Reaction (ERIC-PCR) fingerprints in Enterobacterales isolated from neonatal sepsis. RESULTS: In total, 59 Enterobacterales isolates including 41 (69.5%) Enterobacter species, 15 (25.4%) Klebsiella pneumoniae and 3 (5.1%) Escherichia coli were isolated respectively. Resistance to ceftazidime and cefotaxime was seen in all of isolates. Furthermore, all of them were multidrug-resistant (resistant to three different antibiotic categories). The phenotypic tests showed that 100% of isolates were ESBL-positive. Moreover, AmpC production was observed in 84.7% (n = 50/59) of isolates. Among 59 ESBL-positive isolates, the highest percentage belonged to blaCTX-M-15 gene (66.1%) followed by blaCTX-M (45.8%), blaCTX-M-14 (30.5%), blaSHV (28.8%), and blaTEM (13.6%). The frequency of blaDHA, blaEBC, blaMOX and blaCIT genes were 24%, 24%, 4%, and 2% respectively. ERIC-PCR analysis revealed that Enterobacterales isolates were genetically diverse. The remarkable prevalence of MDR Enterobacterales isolates carrying ESBL and AmpC beta-lactamase genes emphasizes that efficient surveillance measures are essential to avoid the more expansion of drug resistance amongst isolates.


Subject(s)
Anti-Bacterial Agents , Bacterial Proteins , Drug Resistance, Multiple, Bacterial , Enterobacteriaceae Infections , Microbial Sensitivity Tests , Neonatal Sepsis , beta-Lactamases , beta-Lactamases/genetics , Humans , Iran/epidemiology , Infant, Newborn , Drug Resistance, Multiple, Bacterial/genetics , Enterobacteriaceae Infections/microbiology , Enterobacteriaceae Infections/epidemiology , Anti-Bacterial Agents/pharmacology , Prevalence , Bacterial Proteins/genetics , Neonatal Sepsis/microbiology , Neonatal Sepsis/epidemiology , Enterobacteriaceae/genetics , Enterobacteriaceae/drug effects , Enterobacteriaceae/enzymology , Enterobacteriaceae/isolation & purification , Klebsiella pneumoniae/genetics , Klebsiella pneumoniae/drug effects , Klebsiella pneumoniae/isolation & purification , Klebsiella pneumoniae/enzymology , Enterobacter/genetics , Enterobacter/drug effects , Enterobacter/isolation & purification , Enterobacter/enzymology , Escherichia coli/genetics , Escherichia coli/drug effects , Escherichia coli/isolation & purification
2.
J Glob Antimicrob Resist ; 37: 48-52, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38430961

ABSTRACT

OBJECTIVES: KHM-1-metallo-ß-lactamase-producing Enterobacterales strains, of which only a few have been found, were isolated from four inpatients in Osaka, Japan during 2016 to 2020. We compared whole genomes of the four KHM-1-producing isolates, including one Enterobacter hormaechei subsp. hoffmannii, one Escherichia coli, and two Citrobacter freundii. METHODS: These isolates were characterized by whole-genome sequencing, comparative analysis of blaKHM-1-encoding plasmids with earlier reported plasmids, and antimicrobial susceptibility tests. RESULTS: Multilocus sequence typing classified the E. hormaechei subsp. hoffmannii isolate to ST78, the E. coli isolate to ST354, and the two C. freundii isolates to ST95. These isolates harboured various antimicrobial resistance genes aside from blaKHM-1 on their chromosomes and plasmids. In all four isolates, blaKHM-1 was located on 137 kbp to 213 kbp plasmids of IncC replicon type. Although there were common resistance genes such as blaKHM-1-ISEc68, class I integron cassette, and fosG, the four blaKHM-1-encoding plasmids were distinguishable into two lineages based on differences of the resistance gene components and their surrounding regions. CONCLUSION: Because no epidemiological contact was observed among the inpatients, the blaKHM-1-encoding IncC plasmids might have spread horizontally to multiple bacterial species through repeated recombination and insertion.


Subject(s)
Anti-Bacterial Agents , Citrobacter freundii , Enterobacter , Enterobacteriaceae Infections , Microbial Sensitivity Tests , Multilocus Sequence Typing , Plasmids , Whole Genome Sequencing , beta-Lactamases , beta-Lactamases/genetics , Humans , Japan , Plasmids/genetics , Enterobacteriaceae Infections/microbiology , Anti-Bacterial Agents/pharmacology , Enterobacter/genetics , Enterobacter/isolation & purification , Enterobacter/drug effects , Enterobacter/enzymology , Enterobacter/classification , Citrobacter freundii/genetics , Citrobacter freundii/drug effects , Citrobacter freundii/isolation & purification , Escherichia coli/genetics , Escherichia coli/drug effects , Escherichia coli/isolation & purification , Inpatients , Drug Resistance, Multiple, Bacterial/genetics , Genome, Bacterial
3.
Microbiol Spectr ; 9(3): e0199821, 2021 12 22.
Article in English | MEDLINE | ID: mdl-34937191

ABSTRACT

In the context of a recent rise in prevalence of NDM-encoding carbapenemase-producing Enterobacterales (CPE) in the province of QC, Canada, the genetic environment of blaNDM-1 was investigated. Three NDM-producing clinical isolates of Enterobacter hormaechei recovered from hospitalized patients involved in a putative outbreak were further characterized by whole-genome sequencing (WGS). Two isolates were confirmed by pulsed-field gel electrophoresis and WGS to be closely related. In addition to a ∼128 kb IncFII conjugative multidrug-resistance (MDR) plasmid, these isolates possessed a ∼45 kb mobilizable IncR MDR plasmid containing 2 MDR regions: a complex class 1 integron harboring blaNDM-1 and 7 other AMR genes, and the IS26-mph(A)-mrx-mphR(A)-IS6100 azithromycin resistance unit. The predicted antimicrobial resistance (AMR) genes correlated with the antimicrobial susceptibility testing results. The multidrug-resistant phenotype in addition to the presence of two important mobile genetic elements, suggest a potent role as a reservoir of antibiotic resistance for such a small IncR plasmid. IMPORTANCE Analyzing the genetic environment of clinically relevant MDR genes can provide information on the way in which such genes are maintained and disseminated. Understanding this phenomenon is of interest for clinicians as it can also provide insight on where these genes might have been sourced, possibly supporting outbreak investigations.


Subject(s)
Anti-Bacterial Agents/pharmacology , Azithromycin/pharmacology , Enterobacter/drug effects , Enterobacter/genetics , Enterobacteriaceae Infections/microbiology , Plasmids/genetics , beta-Lactamases/metabolism , Disease Outbreaks , Drug Resistance, Bacterial , Enterobacter/enzymology , Enterobacter/isolation & purification , Enterobacteriaceae Infections/epidemiology , Humans , Microbial Sensitivity Tests , Plasmids/metabolism , Quebec/epidemiology , beta-Lactamases/genetics
4.
Antimicrob Resist Infect Control ; 10(1): 166, 2021 11 29.
Article in English | MEDLINE | ID: mdl-34844659

ABSTRACT

ABSRACT: BACKGROUND: To describe the course and intervention of an hospital-wide IMI-Producing Enterobacter ludwigii outbreak. METHODS: This was an outbreak interventional study, done at a tertiary care center in Tel-Aviv, Israel. Data was collected on the course of the outbreak and the demographic and clinical characteristics of all patients involved in the outbreak. The intervention measures included patients' cohorting, contact isolation precautions, environmental cleaning and screening of contacts. The molecular features and phylogeny of outbreak-related isolates were studied by whole-genome based analysis. RESULTS: The outbreak included 34 patients that were colonized by IMI-Producing E. ludwigii and were identified in 24 wards throughout the hospital. Colonization was identified in the first 72 h of admission in 13/34 patients (38.2%). Most patients (91.2%) were admitted from home and had relatively low level of comorbidities. The majority of them (88%) had no recent use of invasive catheters and none had previous carriage of other multi-drug resistant bacteria. All available isolates harbored the blaIMI-17 allele and belonged to Sequence-Type 385. With the exception of two isolates, all isolates were closely related with less than a 20-SNP difference between them. CONCLUSIONS: This outbreak had most likely originated in the community and subsequently disseminated inside our institution. More studies are required in order to elucidate the epidemiology of IMI-Producing E. ludwigii and the possible role of environmental sources in its dissemination.


Subject(s)
Bacterial Proteins/genetics , Cross Infection/epidemiology , Disease Outbreaks/statistics & numerical data , Enterobacter/pathogenicity , Enterobacteriaceae Infections/epidemiology , Enterobacteriaceae Infections/transmission , Hospitals/statistics & numerical data , beta-Lactamases/genetics , Adult , Aged , Aged, 80 and over , Anti-Bacterial Agents/therapeutic use , Bacterial Proteins/biosynthesis , Bacterial Typing Techniques , Cross Infection/microbiology , Disease Outbreaks/prevention & control , Electrophoresis, Gel, Pulsed-Field , Enterobacter/drug effects , Enterobacter/enzymology , Enterobacter/genetics , Enterobacteriaceae Infections/drug therapy , Female , Humans , Infection Control/methods , Israel/epidemiology , Male , Microbial Sensitivity Tests , Middle Aged , Multilocus Sequence Typing , beta-Lactamases/biosynthesis
5.
Int J Mol Sci ; 22(11)2021 May 31.
Article in English | MEDLINE | ID: mdl-34072783

ABSTRACT

Marine mammals have been described as sentinels of the health of marine ecosystems. Therefore, the aim of this study was to investigate (i) the presence of extended-spectrum ß-lactamase (ESBL)- and AmpC-producing Enterobacterales, which comprise several bacterial families important to the healthcare sector, as well as (ii) the presence of Salmonella in these coastal animals. The antimicrobial resistance pheno- and genotypes, as well as biocide susceptibility of Enterobacterales isolated from stranded marine mammals, were determined prior to their rehabilitation. All E. coli isolates (n = 27) were screened for virulence genes via DNA-based microarray, and twelve selected E. coli isolates were analyzed by whole-genome sequencing. Seventy-one percent of the Enterobacterales isolates exhibited a multidrug-resistant (MDR) pheno- and genotype. The gene blaCMY (n = 51) was the predominant ß-lactamase gene. In addition, blaTEM-1 (n = 38), blaSHV-33 (n = 8), blaCTX-M-15 (n = 7), blaOXA-1 (n = 7), blaSHV-11 (n = 3), and blaDHA-1 (n = 2) were detected. The most prevalent non-ß-lactamase genes were sul2 (n = 38), strA (n = 34), strB (n = 34), and tet(A) (n = 34). Escherichia coli isolates belonging to the pandemic sequence types (STs) ST38, ST167, and ST648 were identified. Among Salmonella isolates (n = 18), S. Havana was the most prevalent serotype. The present study revealed a high prevalence of MDR bacteria and the presence of pandemic high-risk clones, both of which are indicators of anthropogenic antimicrobial pollution, in marine mammals.


Subject(s)
Aquatic Organisms/microbiology , Enterobacter/enzymology , Mammals/microbiology , Salmonella/enzymology , beta-Lactamases/biosynthesis , Animals , Anti-Bacterial Agents/pharmacology , Bacterial Proteins/genetics , Bacterial Typing Techniques , Drug Resistance, Bacterial , Enterobacter/drug effects , Enterobacter/genetics , Enterobacter/isolation & purification , Genotype , Microbial Sensitivity Tests , Salmonella/drug effects , Salmonella/genetics , Salmonella/isolation & purification , Virulence Factors/genetics , beta-Lactamases/genetics
6.
Pediatr Infect Dis J ; 40(8): 738-740, 2021 08 01.
Article in English | MEDLINE | ID: mdl-33742614

ABSTRACT

In a cohort of 257 infants with congenital heart disease admitted to the pediatric intensive care unit, 22 infants had positive cultures for extended-spectrum beta-lactamase or AmpC Gram-negative bacteria. These infants had longer exposure to broad-spectrum antibiotics, greater support with invasive devices and longer intensive care and hospital lengths of stay.


Subject(s)
Bacterial Proteins , Cross Infection/microbiology , Gram-Negative Bacterial Infections/complications , Heart Defects, Congenital/complications , beta-Lactam Resistance , beta-Lactamases , Case-Control Studies , Citrobacter/enzymology , Cohort Studies , Critical Illness , Enterobacter/enzymology , Escherichia coli/enzymology , Female , Hospitals, Pediatric , Humans , Infant , Intensive Care Units, Pediatric , Klebsiella/enzymology , Male , Prevalence , Retrospective Studies , Risk Factors , Serratia/enzymology
7.
Microb Drug Resist ; 27(7): 895-903, 2021 Jul.
Article in English | MEDLINE | ID: mdl-33090918

ABSTRACT

Carbapenemase production is constantly increasing among different Enterobacterales species. We analyzed the microbiological characteristics and population structure of all carbapenemase-producing Enterobacter spp. (CP-Ent) isolates recovered at the Ramón y Cajal Hospital between 2005 and 2018. Overall, 178 CP-Ent isolates (60.7% colonization, 39.3% clinical) were recovered from 165 hospitalized patients (165/176, 93.7%; medical [102/165], surgical [34/165], and intensive care unit [29/165] areas), emergency unit (4/176, 2.3%), and ambulatory patients (7/176, 4.0%). In addition, three CP-Ent were found in environmental sources. Clinical samples were mainly urine (37.1%). The most frequent matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF)-identified species were Enterobacter cloacae (n = 85) and Enterobacter asburiae (n = 49). hsp60 gene sequencing showed a higher species diversity than MALDI-TOF: 70 Enterobacter hormaechei-clusters III, VI, VIII; 69 Enterobacter roggenkampii-IV; 15 Enterobacter kobei-II; 9 E. asburiae-I; 3 Enterobacter ludwigii-V; and 1 E. cloacae subsp. dissolvens-XII. Nine Klebsiella aerogenes were also identified. Overall, a high clonal diversity (Simpson Diversity Index >0.90) was found among CP-Ent-clusters. Environmental isolates were clonally related to clinical ones. Amikacin and tigecycline showed the highest susceptibility (>93%). VIM-1 (n = 133/181, 73.5%) and OXA-48 (n = 34/181, 18.8%) carbapenemases were predominant, followed by KPC-2 (n = 9/181, 5.0%), KPC-3 (n = 2/181, 1.1%), VIM-2 (n = 1/181, 0.6%), and two coproducers (VIM-1+KPC-2 and VIM-1+KPC-3). Extended-spectrum beta-lactamase (ESBL) coproduction (14.4%) emerged in 2012, mainly associated with blaSHV-12 (p < 0.001), E. roggenkampii (p < 0.001), and colonization (p = 0.03). VIM-1- and OXA-48-CP-Ent fecal carriers increased in our hospital, particularly between 2011 and 2018 (p < 0.001). Moreover, KPC and OXA-48 producers emerged in 2010 and 2012, respectively. They superimposed over VIM producers, which were persistently recovered since first detection in 2005. These results depict increased complexity over time of CP-Ent.


Subject(s)
Anti-Bacterial Agents/pharmacology , Bacterial Proteins/biosynthesis , Enterobacter/enzymology , Enterobacter/isolation & purification , beta-Lactamases/biosynthesis , Enterobacter/drug effects , Hospitals, University , Humans , Microbial Sensitivity Tests , Spain/epidemiology
8.
Int J Mol Sci ; 21(22)2020 Nov 12.
Article in English | MEDLINE | ID: mdl-33198306

ABSTRACT

Since the discovery of penicillin by Alexander Fleming in 1929 as a therapeutic agent against staphylococci, ß-lactam antibiotics (BLAs) remained the most successful antibiotic classes against the majority of bacterial strains, reaching a percentage of 65% of all medical prescriptions. Unfortunately, the emergence and diversification of ß-lactamases pose indefinite health issues, limiting the clinical effectiveness of all current BLAs. One solution is to develop ß-lactamase inhibitors (BLIs) capable of restoring the activity of ß-lactam drugs. In this review, we will briefly present the older and new BLAs classes, their mechanisms of action, and an update of the BLIs capable of restoring the activity of ß-lactam drugs against ESKAPE (Enterococcus spp., Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp.) pathogens. Subsequently, we will discuss several promising alternative approaches such as bacteriophages, antimicrobial peptides, nanoparticles, CRISPR (clustered regularly interspaced short palindromic repeats) cas technology, or vaccination developed to limit antimicrobial resistance in this endless fight against Gram-negative pathogens.


Subject(s)
Anti-Bacterial Agents/pharmacology , Drug Resistance, Multiple, Bacterial , beta-Lactamases/metabolism , Acinetobacter baumannii/drug effects , Acinetobacter baumannii/enzymology , Animals , Bacteriophages , CRISPR-Cas Systems , Carbapenems/pharmacology , Enterobacter/drug effects , Enterobacter/enzymology , Enterococcus/drug effects , Enterococcus/enzymology , Humans , Klebsiella pneumoniae/drug effects , Klebsiella pneumoniae/enzymology , Metal Nanoparticles/chemistry , Microbial Sensitivity Tests , Pore Forming Cytotoxic Proteins/pharmacology , Pseudomonas aeruginosa/drug effects , Pseudomonas aeruginosa/enzymology , Staphylococcus aureus/drug effects , Staphylococcus aureus/enzymology , Vaccination , beta-Lactamase Inhibitors/pharmacology
9.
J Basic Microbiol ; 60(8): 699-711, 2020 Aug.
Article in English | MEDLINE | ID: mdl-32510669

ABSTRACT

Bis(2-hydroxyethyl) terephthalate (BHET) is an important compound produced from poly(ethylene terephthalate) (PET) cleavage. It was selected as the representative substance for the study of PET degradation. A bacterial strain HY1 that could degrade BHET was isolated and identified as Enterobacter sp. The optimal temperature and pH for BHET biodegradation were determined to be 30°C and 8.0, respectively. The half-life of degradation was 70.20 h at an initial BHET concentration of 1,000 mg/L. The results of metabolites' analysis by liquid chromatograph-mass spectrometer revealed that BHET was first converted to mono-(2-hydroxyethyl) terephthalate (MHET) and then to terephthalic acid. Furthermore, an esterase-encoding gene, estB, was cloned from strain HY1, and the expressed enzyme EstB was characterized. The esterase has a molecular mass of approximately 25.13 kDa, with an isoelectric point of 4.68. Its optimal pH and temperature were pH 8.0 and 40°C, respectively. The analysis of the enzymatic products showed that EstB could hydrolyze one ester bond of BHET to MHET. To the best of authors' knowledge, this is the first report on the biodegradation characteristics of BHET by a member of the Enterobacter genus.


Subject(s)
Bacterial Proteins/metabolism , Enterobacter/metabolism , Esterases/metabolism , Phthalic Acids/metabolism , Amino Acid Sequence , Bacterial Proteins/chemistry , Bacterial Proteins/genetics , Biodegradation, Environmental , Enterobacter/classification , Enterobacter/enzymology , Enterobacter/genetics , Esterases/chemistry , Esterases/genetics , Hydrogen-Ion Concentration , Hydrolysis , Kinetics , Molecular Weight , Phylogeny , Substrate Specificity , Temperature
10.
Biomolecules ; 10(6)2020 06 22.
Article in English | MEDLINE | ID: mdl-32580522

ABSTRACT

The present study described the extracellular synthesis of silver nanoparticles (AgNPs) using environmental bacterial isolate Citrobacter spp. MS5 culture supernatant. To our best knowledge, no previous study reported the biosynthesis of AgNPs using this bacterial isolate. The biosynthesized AgNPs were characterized using different techniques like UV-Vis spectroscopy, fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) equipped with energy dispersive X-ray (EDX). The analysis of UV-Vis spectra revealed absorption maxima at 415 nm due to surface plasmon resonance (SPR) indicated the formation of AgNPs and FTIR spectrum confirmed the participation of proteins molecule in AgNPs synthesis. XRD and EDX spectrum confirmed the metallic and crystalline nature of AgNPs. TEM and SEM showed spherical nanoparticles with a size range of 5-15 nm. The biosynthesized AgNPs showed effective independent as well as enhanced combined antibacterial activity against extended spectrum ß-lactamase (ESBL) producing multidrug resistant Gram-negative bacteria. Further, effective antifungal activity of AgNPs was observed towards pathogenic Candida spp. The present study provides evidence for eco-friendly biosynthesis of well-characterized AgNPs and their potential antibacterial as well as antifungal activity.


Subject(s)
Anti-Bacterial Agents/pharmacology , Antifungal Agents/pharmacology , Citrobacter/chemistry , Metal Nanoparticles/chemistry , Silver/pharmacology , beta-Lactamase Inhibitors/pharmacology , Anti-Bacterial Agents/biosynthesis , Anti-Bacterial Agents/chemistry , Antifungal Agents/chemistry , Antifungal Agents/metabolism , Candida/drug effects , Citrobacter/isolation & purification , Citrobacter/metabolism , Enterobacter/drug effects , Enterobacter/enzymology , Escherichia coli/drug effects , Escherichia coli/enzymology , Klebsiella pneumoniae/drug effects , Klebsiella pneumoniae/enzymology , Microbial Sensitivity Tests , Particle Size , Silver/chemistry , Silver/metabolism , Surface Properties , beta-Lactamase Inhibitors/chemistry , beta-Lactamase Inhibitors/metabolism , beta-Lactamases/metabolism
11.
J Agric Food Chem ; 68(18): 5232-5240, 2020 May 06.
Article in English | MEDLINE | ID: mdl-32293876

ABSTRACT

Patulin contamination is a worldwide concern due to its significant impact on human health. Several yeast strains have been screened for patulin biodegradation; however, little information is available on bacterial strains and their mechanism of degradation. In the present study, we isolated a bacterial strain TT-09 and identified it as Enterobacter cloacae subsp. dissolvens based on the BioLog system and 16S rDNA phylogenetic analysis. The strain was demonstrated to be able to transform patulin into E-ascladiol. Isobaric tags for relative and absolute quantitation and reverse transcription quantitative polymerase chain reaction analyses provided evidence that ribonucleoside diphosphate reductase (NrdA), an important enzyme involved in DNA biosynthesis, plays a crucial role in patulin degradation. Deletion of nrdA resulted in a total loss in the ability to degrade patulin in TT-09. These results indicate a new function for NrdA in mycotoxin biodegradation. The present study provides evidence for understanding a new mechanism of patulin degradation and information that can be used to develop new approaches for managing patulin contamination.


Subject(s)
Bacterial Proteins/metabolism , Enterobacter/enzymology , Patulin/metabolism , Ribonucleoside Diphosphate Reductase/metabolism , Bacterial Proteins/genetics , Biodegradation, Environmental , Enterobacter/classification , Enterobacter/genetics , Enterobacter/metabolism , Phylogeny , Ribonucleoside Diphosphate Reductase/genetics
12.
Nat Commun ; 11(1): 466, 2020 01 24.
Article in English | MEDLINE | ID: mdl-31980604

ABSTRACT

Carbapenem-resistant Enterobacteriaceae (CRE) represent an urgent threat to human health. Here we report the application of several complementary whole-genome sequencing (WGS) technologies to characterise a hospital outbreak of blaIMP-4 carbapenemase-producing E. hormaechei. Using Illumina sequencing, we determined that all outbreak strains were sequence type 90 (ST90) and near-identical. Comparison to publicly available data linked all outbreak isolates to a 2013 isolate from the same ward, suggesting an environmental source in the hospital. Using Pacific Biosciences sequencing, we resolved the complete context of the blaIMP-4 gene on a large IncHI2 plasmid carried by all IMP-4-producing strains across different hospitals. Shotgun metagenomic sequencing of environmental samples also found evidence of ST90 E. hormaechei and the IncHI2 plasmid within the hospital plumbing. Finally, Oxford Nanopore sequencing rapidly resolved the true relationship of subsequent isolates to the initial outbreak. Overall, our strategic application of three WGS technologies provided an in-depth analysis of the outbreak.


Subject(s)
Bacterial Proteins/biosynthesis , Bacterial Proteins/genetics , Carbapenem-Resistant Enterobacteriaceae/enzymology , Carbapenem-Resistant Enterobacteriaceae/genetics , Disease Outbreaks , Enterobacter/enzymology , Enterobacter/genetics , Enterobacteriaceae Infections/epidemiology , beta-Lactamases/biosynthesis , beta-Lactamases/genetics , Burns/microbiology , Carbapenem-Resistant Enterobacteriaceae/pathogenicity , Cross Infection/epidemiology , Cross Infection/microbiology , Drug Resistance, Multiple, Bacterial/genetics , Enterobacter/isolation & purification , Enterobacteriaceae Infections/microbiology , Genome, Bacterial , Humans , Queensland/epidemiology , R Factors/genetics , Sanitary Engineering , Tertiary Care Centers , Whole Genome Sequencing/methods , beta-Lactam Resistance/genetics
13.
Appl Environ Microbiol ; 86(2)2020 01 07.
Article in English | MEDLINE | ID: mdl-31676473

ABSTRACT

The organoarsenical feed additive 4-hydroxy-3-nitrobenzenearsonic acid (roxarsone [ROX]) is widely used and released into the environment. We previously showed a two-step pathway of ROX transformation by Enterobacter sp. strain CZ-1 involving the reduction of ROX to 3-amino-4-hydroxyphenylarsonic acid (3-AHPAA) and the acetylation of 3-AHPAA to N-acetyl-4-hydroxy-m-arsanilic acid (N-AHPAA) (K. Huang, H. Peng, F. Gao, Q. Liu, et al., Environ Pollut 247:482-487, 2019, https://doi.org/10.1016/j.envpol.2019.01.076). In this study, we identified two nhoA genes (nhoA1 and nhoA2), encoding N-hydroxyarylamine O-acetyltransferases, as responsible for 3-AHPAA acetylation in Enterobacter sp. strain CZ-1. The results of genetic disruption and complementation showed that both nhoA genes are involved in ROX biotransformation and that nhoA1 is the major 3-AHPAA acetyltransferase gene. Quantitative reverse transcription-PCR analysis showed that the relative expression level of nhoA1 was 3-fold higher than that of nhoA2 Each of the recombinant NhoAs was overexpressed in Escherichia coli BL21 and homogenously purified as a dimer by affinity chromatography. Both purified NhoAs catalyzed acetyl coenzyme A-dependent 3-AHPAA acetylation. The Km values of 3-AHPAA for NhoA1 and NhoA2 were 151.5 and 428.3 µM, respectively. Site-directed mutagenesis experiments indicated that two conserved arginine and cysteine residues of each NhoA were necessary for their enzyme activities.IMPORTANCE Roxarsone (ROX) is an organoarsenic feed additive that has been widely used in poultry industries for growth promotion, coccidiosis control, and meat pigmentation improvement for more than 70 years. Most ROX is excreted in the litter and dispersed into the environment, where it is transformed by microbes into different arsenic-containing compounds. A major product of ROX transformation is N-acetyl-4-hydroxy-m-arsanilic acid (N-AHPAA), which is also used as a clinical drug for treating refractory bacterial vaginosis. Here, we report the cloning and functional characterization of two genes encoding N-hydroxyarylamine O-acetyltransferases, NhoA1 and NhoA2, in Enterobacter sp. strain CZ-1, which catalyze the acetylation of 3-amino-4-hydroxyphenylarsonic acid (3-AHPAA) formed by the reduction of ROX to N-AHPAA. This study provides new insights into the function of N-hydroxyarylamine O-acetyltransferase in the transformation of an important organoarsenic compound.


Subject(s)
Acetyltransferases/metabolism , Arsenicals/metabolism , Bacterial Proteins/metabolism , Enterobacter/metabolism , Acetylation , Enterobacter/enzymology , Metabolic Networks and Pathways
15.
Biochem Biophys Res Commun ; 519(2): 274-279, 2019 11 05.
Article in English | MEDLINE | ID: mdl-31493870

ABSTRACT

Lipases are widely present in various plants, animals and microorganisms, constituting a large category of enzymes. They have the ability to catalyze the cleavage of ester bonds. The lipase CinB from Enterobacter asburiae (E. asburiae) is an acetyl esterase. The primary amino acid sequence suggests that the EaCinB protein belongs to the α/ß-hydrolase (ABH) superfamily of the esterase/lipase superfamily. However, its molecular functions have not yet been determined. Here, we report the crystal structure of E. asburiae CinB at a 1.45 Šresolution. EaCinB contains a signal peptide, cap domain and catalytic domain. The active site of EaCinB contains the catalytic triad (Ser180-His307-Asp277) on the catalytic domain. The oxyanion hole is composed of Gly106 and Gly107 within the conserved sequence motif HGGG (amino acid residues 106-109). The substrate is accessible between the α1 and α2 helices or the α1 helix and catalytic domain. Narrow substrate pockets are formed by the α2 helix of the cap domain. Site-directed mutagenesis showed that EaCinB-W208H exhibits a higher catalytic ability than EaCinB-WT by approximately nine times. Our results provide insight into the molecular function of EaCinB.


Subject(s)
Enterobacter/enzymology , Lipase/chemistry , Lipase/metabolism , Crystallography, X-Ray , Lipase/genetics , Models, Molecular , Substrate Specificity
16.
mSphere ; 4(5)2019 09 11.
Article in English | MEDLINE | ID: mdl-31511372

ABSTRACT

An Enterobacter hormaechei isolate harboring blaVIM-4 and mcr-9 was recovered from a pediatric patient in a U.S. hospital. The blaVIM-4 and mcr-9 genes are carried on the same IncH12 plasmid, pME-1a. The isolate tested susceptible to colistin, without observed induction of colistin resistance. The mcr-9 gene is located between two insertion elements, IS903 and IS1, but lacks the downstream regulatory genes (qseC and qseB) found in other isolates that harbor mcr-9IMPORTANCE We describe the complete genome assembly and sequence of a clinical Enterobacter isolate harboring both blaVIM-4 and mcr-9 recovered from a pediatric patient in the United States with a history of travel to Egypt. Moreover, to the best of our knowledge, this is the first report of an Enterobacter isolate harboring both blaVIM-4 and mcr-9 from the United States. The blaVIM-4 and mcr-9 genes are carried on the same IncH12 plasmid, pME-1a. The isolate tested susceptible to colistin, without observed induction of colistin resistance. The mcr-9 gene is located between two insertion elements, IS903 and IS1, but lacks the downstream regulatory genes (qseC and qseB) found in other isolates that harbor mcr-9.


Subject(s)
Enterobacter/genetics , Enterobacter/isolation & purification , Genome, Bacterial , beta-Lactamases/genetics , Child, Preschool , Egypt , Enterobacter/enzymology , Enterobacteriaceae Infections/diagnosis , Enterobacteriaceae Infections/microbiology , Humans , Male , Plasmids/genetics , Sequence Analysis, DNA , Travel-Related Illness , United States
17.
Food Chem ; 298: 124999, 2019 Nov 15.
Article in English | MEDLINE | ID: mdl-31261010

ABSTRACT

Glycoside hydrolase family 8 (GH8) includes endoglucanases, lichenases, chitosanases and xylanases, which are essential for polysaccharides breakdown. In this work, we studied a thermally stable GH8 from the cellulose synthase complex of Enterobacter sp. R1, for deconstruction of ß-glucans. The biochemical characterization of the recombinant GH8ErCel showed high specificity towards barley ß-glucan and lichenan and lower activity on carboxymethylcellulose and swollen cellulose, yielding different length oligosaccharides. By molecular modeling, six conserved subsites for glucose binding and some possible determinants for its lack of xylanase and chitosanase activity were identified. GH8ErCel was active at a broad range of pH and temperature and presented remarkable stability at 60 °C. Additionally, it hydrolyzed ß-glucan from oat and wheat brans mainly to tri- and tetraoligosaccharides. Therefore, GH8ErCel may be a good candidate for enzymatic deconstruction of ß-glucans at high temperature in food and feed industries, including the production of prebiotics and functional foods.


Subject(s)
Cellulase/chemistry , Cellulase/metabolism , Cellulose/metabolism , Enterobacter/enzymology , beta-Glucans/metabolism , Argentina , Carboxymethylcellulose Sodium/metabolism , Cellulase/genetics , Enterobacter/genetics , Enterobacter/isolation & purification , Enzyme Stability , Glucans/metabolism , Glucose/metabolism , Hydrogen-Ion Concentration , Hydrolysis , Oligosaccharides/metabolism , Recombinant Proteins/genetics , Recombinant Proteins/metabolism , Soil Microbiology , Substrate Specificity , Temperature , beta-Glucans/chemistry
18.
J Glob Antimicrob Resist ; 18: 52-54, 2019 09.
Article in English | MEDLINE | ID: mdl-31181270

ABSTRACT

OBJECTIVES: The aim of this study was to investigate the characteristics and complete genome sequence of an IMP-8, CTX-M-14, CTX-M-3 and QnrS1 co-producing multidrug-resistant Enterobacter asburiae isolate (EN3600) from a patient with wound infection. METHODS: Species identification was confirmed by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF/MS). Carbapenemase genes were identified by PCR and Sanger sequencing. The complete genome sequence of E. asburiae EN3600 was obtained using a PacBio RS II platform. Genome annotation was done by Rapid Annotation using Subsystem Technology (RAST) server. Acquired antimicrobial resistance genes (ARGs) and plasmid replicons were detected using ResFinder 2.1 and PlasmidFinder 1.3, respectively. RESULTS: The genome of E. asburiae EN3600 consists of a 4.8-Mbp chromosome and five plasmids. The annotated genome contains various ARGs conferring resistance to aminoglycosides, ß-lactams, fluoroquinolones, fosfomycin, macrolides, phenicols, rifampicin and sulfonamides. In addition, plasmids of incompatibility (Inc) groups IncHI2A, IncFIB(pECLA), IncFIB(pQil) and IncP1 were identified. The genes blaIMP-8, blaCTX-M-14 and blaCTX-M-3 were located on different plasmids. The blaIMP-8 gene was carried by an 86-kb IncFIB(pQil) plasmid. The blaCTX-M-3 and qnrS1 genes were co-harboured by an IncP1 plasmid. In addition, blaCTX-M-14 was associated with blaTEM-1B, blaOXA-1, catB3 and sul1 genes in a 116-kb non-typeable plasmid. CONCLUSION: To our knowledge, this is the first complete genome sequence of an E. asburiae isolate co-producing IMP-8, CTX-M-14, CTX-M-3 and QnrS1. This genome may facilitate the understanding of the resistome, pathogenesis and genomic features of Enterobacter cloacae complex (ECC) and will provide valuable information for accurate identification of ECC.


Subject(s)
Enterobacter/genetics , Whole Genome Sequencing , Wound Infection/microbiology , beta-Lactamases/genetics , Anti-Bacterial Agents/pharmacology , Bacterial Proteins/genetics , Drug Resistance, Multiple, Bacterial/genetics , Enterobacter/drug effects , Enterobacter/enzymology , Humans , Microbial Sensitivity Tests , Sequence Analysis, DNA
20.
J Med Microbiol ; 68(6): 952-956, 2019 Jun.
Article in English | MEDLINE | ID: mdl-31107204

ABSTRACT

Exploiting the immunosuppressive, analgesic and highly addictive properties of morphine could increase the success of a bacterial pathogen. Therefore, we performed sequence similarity searches for two morphine biosynthesis demethylases in bacteria. For thebaine 6-O-demethylase and codeine O-demethylase, we found strong alignments to three (Pseudomonas aeruginosa, Klebsiella pneumoniae and Acinetobacter baumannii) of the six ESKAPE pathogens (Enterococcus faecalis, Staphylococcus aureus, K. pneumoniae, A. baumannii, P. aeruginosa and Enterobacter species) that are commonly associated with drug resistance and nosocomial infections. Expression of the aligned sequence found in P. aeruginosa (NP_252880.1/PA4191) is upregulated in isolates obtained from cystic fibrosis patients. Our findings provide putative mechanistic targets for understanding the role of morphine in pathogenicity.


Subject(s)
Acinetobacter baumannii/enzymology , Cross Infection/microbiology , Enterobacter/enzymology , Klebsiella pneumoniae/enzymology , Oxidoreductases, O-Demethylating/genetics , Pseudomonas aeruginosa/enzymology , Staphylococcus aureus/enzymology , Acinetobacter baumannii/genetics , Amino Acid Sequence , Bacterial Proteins/genetics , Codeine/metabolism , Enterobacter/genetics , Humans , Klebsiella pneumoniae/genetics , Morphine Derivatives/metabolism , Opiate Alkaloids/administration & dosage , Pseudomonas aeruginosa/genetics , Sequence Alignment , Staphylococcus aureus/genetics , Thebaine/metabolism
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