scholarly journals A transferrable IncL/M plasmid harboring a gene encoding IMP-1 metallo-β-lactamase in clinical isolates of Enterobacteriaceae

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Nobuyoshi Mori ◽  
Tatsuya Tada ◽  
Satoshi Oshiro ◽  
Kyoko Kuwahara-Arai ◽  
Teruo Kirikae ◽  
...  

Abstract Background The worldwide spread of carbapenemase-producing Enterobacteriaceae (CPE) has reduced the clinical utility of carbapenems. Plasmids often play an important role in the spread of genes encoding drug-resistance factors, especially in the horizontal transfer of these genes among species of Enterobacteriaceae. This study describes a patient infected with three species of CPE carrying an identical transferrable IncL/M plasmid. Methods Clinical isolates of CPE were collected at St. Luke’s International Hospital, Tokyo, Japan, from 2015 to 2019. Three species of CPE isolates, Enterobacter cloacae, Klebsiella aerogenes and Serratia marcescens, were isolated from a patient who developed severe gallstone pancreatitis associated with bloodstream infection, with all three isolates producing IMP-1 metallo-β-lactamase. The complete sequences of the plasmids of the three isolates were determined by both MiSeq and MinION. The medical chart of this patient was retrospectively reviewed conducted to obtain relevant clinical information. Results The three CPE species carried an IncL/M plasmid, pSL264, which was 81,133 bp in size and harbored blaIMP-1. The genetic environment surrounding blaIMP-1 consisted of int1-blaIMP-1-aac(6’)-IIc-qacL-qacEdelta1-sul1-istB-IS21. Conjugation experiments showed that S. marcescens could transmit the plasmid to E. cloacae and K. aerogenes. In contrast, pSL264 could not transfer from E. cloacae or K. aerogenes to S. marcescens. Conclusion The IncL/M plasmid pSL264 harboring blaIMP-1 was able to transfer among different species of Enterobacteriaceae in a patient receiving long-term antimicrobial treatment. The worldwide emergence and spread of IncL/M plasmids harboring carbapenemase-encoding genes among species of Enterobacteriaceae is becoming a serious public health hazard.

2020 ◽  
Vol 14 (07) ◽  
pp. 772-780
Author(s):  
Eveline Zuniga ◽  
Nilson Roberti Benites ◽  
Aline Santana da Hora ◽  
Priscila Luiza Mello ◽  
Marco Antonio Laes ◽  
...  

Introduction: Staphylococci are the most important agents associated with bovine mastitis. This study aimed at characterizing resistance factors to antimicrobials in Staphylococcus spp. isolated from the milk of cows with subclinical mastitis. Methodology: In vitro resistance of 243 Staphylococcus spp. isolates to antimicrobials commonly used in clinical practice was evaluated. The detection and expression of genes encoding resistance mecA (gene encoding penicillin binding protein 2a) mecALGA251 (mecA homologue), blaZ (gene encoding penicillin resistance), femA and femB (genes encoding essential factors - A and B - for the expression of methicillin resistance) and aacA-aphD (gene encoding for a bifunctional enzyme that confers resistance to gentamicin) using PCR and RT-PCR was investigated. Results: One or more genes encoding resistance to different antimicrobials were detected in 184 Staphylococcus spp. samples. The femA and femB genes were the most frequent. Regarding the variables’ detection (N = number of strains) and expression (% of strains), the following results were obtained: blaZ (N = 40 – 82.5%), femA (N = 147 – 47.6%), aacAaphD (N = 30 – 43.3%), femB (N = 138 – 29.7%), mecA (N = 33 – 27.3%), mecALGA251 (N = 01 – 0.0%). There was a higher occurrence of phenotypic resistant strains for amoxicillin, ampicillin and penicillin in isolates positive for detection and/or expression of blaZ gene when compared with the other genes. Conclusions: The present study provides new information on genotypic traits of Staphylococcus isolates from bovine subclinical mastitis especially regarding the evaluation of expression of genes associated with antimicrobial resistance in Staphylococcus spp. using molecular tools.


Microbiology ◽  
2004 ◽  
Vol 150 (4) ◽  
pp. 967-978 ◽  
Author(s):  
C. Viana-Niero ◽  
P. E. de Haas ◽  
D. van Soolingen ◽  
S. C. Leão

The Mycobacterium tuberculosis genome contains four highly related genes which present significant similarity to Pseudomonas aeruginosa genes encoding phospholipase C enzymes. Three of these genes, plcA, plcB and plcC, are organized in tandem (locus plcABC). The fourth gene, plcD, is located in a different region. This study investigates variations in plcABC and plcD genes in clinical isolates of M. tuberculosis, Mycobacterium africanum and ‘Mycobacterium canettii’. Genetic polymorphisms were examined by PCR, Southern blot hybridization, sequence analysis and RT-PCR. Seven M. tuberculosis isolates contain insertions of IS6110 elements within plcA, plcC or plcD. In 19 of 25 M. tuberculosis isolates examined, genomic deletions were identified, resulting in loss of parts of genes or complete genes from the plcABC and/or plcD loci. Partial plcD deletion was observed in one M. africanum isolate. In each case, deletions were associated with the presence of a copy of the IS6110 element and in all occurrences IS6110 was transposed in the same orientation. A mechanism of deletion resulting from homologous recombination of two copies of IS6110 was recognized in a group of genetically related M. tuberculosis isolates. Five M. tuberculosis isolates presented major polymorphisms in the plcABC and plcD regions, along with loss of expression competence that affected all four plc genes. Phospholipase C is a well-known bacterial virulence factor. The precise role of phospholipase C in the pathogenicity of M. tuberculosis is unknown, but considering the potential importance that the plc genes may have in the virulence of the tubercle bacillus, the study of isolates cultured from patients with active tuberculosis bearing genetic variations affecting these genes may provide insights into the significance of phospholipase C enzymes for tuberculosis pathogenicity.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
José Francisco Cruz-Pérez ◽  
Roxana Lara-Oueilhe ◽  
Cynthia Marcos-Jiménez ◽  
Ricardo Cuatlayotl-Olarte ◽  
María Luisa Xiqui-Vázquez ◽  
...  

AbstractThe plant growth-promoting bacterium Azospirillum brasilense contains several genes encoding proteins involved in the biosynthesis and degradation of the second messenger cyclic-di-GMP, which may control key bacterial functions, such as biofilm formation and motility. Here, we analysed the function and expression of the cdgD gene, encoding a multidomain protein that includes GGDEF-EAL domains and CHASE and PAS domains. An insertional cdgD gene mutant was constructed, and analysis of biofilm and extracellular polymeric substance production, as well as the motility phenotype indicated that cdgD encoded a functional diguanylate protein. These results were correlated with a reduced overall cellular concentration of cyclic-di-GMP in the mutant over 48 h compared with that observed in the wild-type strain, which was recovered in the complemented strain. In addition, cdgD gene expression was measured in cells growing under planktonic or biofilm conditions, and differential expression was observed when KNO3 or NH4Cl was added to the minimal medium as a nitrogen source. The transcriptional fusion of the cdgD promoter with the gene encoding the autofluorescent mCherry protein indicated that the cdgD gene was expressed both under abiotic conditions and in association with wheat roots. Reduced colonization of wheat roots was observed for the mutant compared with the wild-type strain grown in the same soil conditions. The Azospirillum-plant association begins with the motility of the bacterium towards the plant rhizosphere followed by the adsorption and adherence of these bacteria to plant roots. Therefore, it is important to study the genes that contribute to this initial interaction of the bacterium with its host plant.


Genetics ◽  
1993 ◽  
Vol 133 (4) ◽  
pp. 999-1007
Author(s):  
R G Gregerson ◽  
L Cameron ◽  
M McLean ◽  
P Dennis ◽  
J Strommer

Abstract In most higher plants the genes encoding alcohol dehydrogenase comprise a small gene family, usually with two members. The Adh1 gene of Petunia has been cloned and analyzed, but a second identifiable gene was not recovered from any of three genomic libraries. We have therefore employed the polymerase chain reaction to obtain the major portion of a second Adh gene. From sequence, mapping and northern data we conclude this gene encodes ADH2, the major anaerobically inducible Adh gene of Petunia. The availability of both Adh1 and Adh2 from Petunia has permitted us to compare their structures and patterns of expression to those of the well-studied Adh genes of maize, of which one is highly expressed developmentally, while both are induced in response to hypoxia. Despite their evolutionary distance, evidenced by deduced amino acid sequence as well as taxonomic classification, the pairs of genes are regulated in strikingly similar ways in maize and Petunia. Our findings suggest a significant biological basis for the regulatory strategy employed by these distant species for differential expression of multiple Adh genes.


2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Yan Le Ho ◽  
Pui Fong Ng ◽  
Sotheenathan Krishinan ◽  
Basheer Ahamed Abdul Kareem

Abstract Background Papillary fibroelastomas are rare but benign cardiac tumour that are often found on cardiac valvular surfaces. Their clinical manifestations ranging from clinically asymptomatic to substantial complications that are usually secondary to systemic embolism. Multiple theories have been proposed to explain the pathophysiology of its formation. Case presentation We reported a rare case of large papillary fibroelastoma in the right atrium of a young gentleman which was complicated with pulmonary embolism. Transthoracic echocardiography identified a large pedunculated mass measuring 3.4cmX3.4cmX2cm in right atrium with stalk attached to interatrial septum. The intracardiac mass was resected surgically, which revealed papillary fibroelastoma in histology examination. Conclusion Differential diagnosis of intracardiac masses requires clinical information, laboratory tests and imaging modalities including echocardiography. Incidentally discovered papillary fibroelastomas are treated on the basis of their sizes, site, mobility and potential embolic complications. Due to the embolic risk inherent to intraacardiac masses, surgical resection represents an effective curative protocol in treating both symptomatic and asymptomatic right sided and left sided papillary fibroelastomas, with excellent long term postoperative prognosis.


2021 ◽  
Vol 11 (6) ◽  
pp. 526
Author(s):  
Yejin Lee ◽  
Youn Jung Kim ◽  
Hong-Keun Hyun ◽  
Jae-Cheoun Lee ◽  
Zang Hee Lee ◽  
...  

Hereditary dentin defects can be categorized as a syndromic form predominantly related to osteogenesis imperfecta (OI) or isolated forms without other non-oral phenotypes. Mutations in the gene encoding dentin sialophosphoprotein (DSPP) have been identified to cause dentinogenesis imperfecta (DGI) Types II and III and dentin dysplasia (DD) Type II. While DGI Type I is an OI-related syndromic phenotype caused mostly by monoallelic mutations in the genes encoding collagen type I alpha 1 chain (COL1A1) and collagen type I alpha 2 chain (COL1A2). In this study, we recruited families with non-syndromic dentin defects and performed candidate gene sequencing for DSPP exons and exon/intron boundaries. Three unrelated Korean families were further analyzed by whole-exome sequencing due to the lack of the DSPP mutation, and heterozygous COL1A2 mutations were identified: c.3233G>A, p.(Gly1078Asp) in Family 1 and c.1171G>A, p.(Gly391Ser) in Family 2 and 3. Haplotype analysis revealed different disease alleles in Families 2 and 3, suggesting a mutational hotspot. We suggest expanding the molecular genetic etiology to include COL1A2 for isolated dentin defects in addition to DSPP.


Author(s):  
Vanessa Kogel ◽  
Stefanie Trinh ◽  
Natalie Gasterich ◽  
Cordian Beyer ◽  
Jochen Seitz

AbstractAstrocytes are the most abundant cell type in the brain and crucial to ensure the metabolic supply of neurons and their synapse formation. Overnutrition as present in patients suffering from obesity causes astrogliosis in the hypothalamus. Other diseases accompanied by malnutrition appear to have an impact on the brain and astrocyte function. In the eating disorder anorexia nervosa (AN), patients suffer from undernutrition and develop volume reductions of the cerebral cortex, associated with reduced astrocyte proliferation and cell count. Although an effect on astrocytes and their function has already been shown for overnutrition, their role in long-term undernutrition remains unclear. The present study used primary rat cerebral cortex astrocytes to investigate their response to chronic glucose starvation. Cells were grown with a medium containing a reduced glucose concentration (2 mM) for 15 days. Long-term glucose starvation increased the expression of a subset of pro-inflammatory genes and shifted the primary astrocyte population to the pro-inflammatory A1-like phenotype. Moreover, genes encoding for proteins involved in the unfolded protein response were elevated. Our findings demonstrate that astrocytes under chronic glucose starvation respond with an inflammatory reaction. With respect to the multiple functions of astrocytes, an association between elevated inflammatory responses due to chronic starvation and alterations found in the brain of patients suffering from undernutrition seems possible.


2002 ◽  
Vol 46 (6) ◽  
pp. 1823-1830 ◽  
Author(s):  
Jean-Denis Docquier ◽  
Fabrizio Pantanella ◽  
Francesco Giuliani ◽  
Maria Cristina Thaller ◽  
Gianfranco Amicosante ◽  
...  

ABSTRACT The sequenced chromosome of Caulobacter crescentus CB15 encodes a hypothetical protein that exhibits significant similarity (30 to 35% identical residues) to metallo-β-lactamases of subclass B3. An allelic variant of this gene (divergent by 3% of its nucleotides) was cloned in Escherichia coli from C. crescentus type strain DSM4727. Expression studies confirmed the metallo-β-lactamase activity of its product, CAU-1. The enzyme produced in E. coli was purified by two ion-exchange chromatography steps. CAU-1 contains a 29-kDa polypeptide with an alkaline isoelectric pH (>9), and unlike the L1 enzyme of Stenotrophomonas maltophilia, the native form is monomeric. Kinetic analysis revealed a preferential activity toward penicillins, carbapenems, and narrow-spectrum cephalosporins, while oxyimino cephalosporins were poorly or not hydrolyzed. Affinities for the various β-lactams were poor overall (Km values were always >100 μM and often >400 μM). The interaction with divalent ion chelators appeared to occur by a mechanism similar to that prevailing in other members of subclass B3. In C. crescentus, the CAU-1 enzyme is produced independently of β-lactam exposure and, interestingly, the bla CAU determinant is bracketed by three other genes, including two genes encoding enzymes involved in methionine biosynthesis and a gene encoding a putative transcriptional regulator, in an operon-like structure. The CAU-1 enzyme is the first example of a metallo-β-lactamase in a member of the α subdivision of the class Proteobacteria.


2017 ◽  
Vol 18 (1) ◽  
pp. 40-46 ◽  
Author(s):  
Ji Min Lee ◽  
Woo Chul Chung ◽  
Hea Jung Sung ◽  
Yeon-Ji Kim ◽  
Gun Jung Youn ◽  
...  

1996 ◽  
Vol 16 (8) ◽  
pp. 4305-4311 ◽  
Author(s):  
X Liu ◽  
B Li ◽  
GorovskyMA

Although variants have been identified for every class of histone, their functions remain unknown. We have been studying the histone H2A variant hv1 in the ciliated protozoan Tetrahymena thermophila. Sequence analysis indicates that hv1 belongs to the H2A.F/Z type of histone variants. On the basis of the high degree of evolutionary conservation of this class of histones, they are proposed to have one or more distinct and essential functions that cannot be performed by their major H2A counterparts. Considerable evidence supports the hypothesis that the hv1 protein in T. thermophila and hv1-like proteins in other eukaryotes are associated with active chromatin. In T. thermophila, simple mass transformation and gene replacement techniques have recently become available. In this report, we demonstrate that either the HTA1 gene or the HTA2 gene, encoding the major H2As, can be completely replaced by disrupted genes in the polyploid, transcriptionally active macronucleus, indicating that neither of the two genes is essential. However, only some of the HTA3 genes encoding hv1 can be replaced by disrupted genes, indicating that the H2A.F/Z type variants have an essential function that cannot be performed by the major H2A genes. Thus, an essential gene in T. thermophila can be defined by the fact that it can be partially, but not completely, eliminated from the polyploid macronucleus. To our knowledge, this study represents the first use of gene disruption technology to study core histone gene function in any organism other than yeast and the first demonstration of an essential gene in T. thermophila using these methods. When a rescuing plasmid carrying a wild-type HTA3 gene was introduced into the T. thermophila cells, the endogenous chromosomal HTA3 could be completely replaced, defining a gene replacement strategy that can be used to analyze the function of essential genes.


Sign in / Sign up

Export Citation Format

Share Document