-
Clinical Infectious Diseases : An... Sep 2019Understanding the nuances of AmpC β-lactamase-mediated resistance can be challenging, even for the infectious diseases specialist. AmpC resistance can be classified... (Review)
Review
Understanding the nuances of AmpC β-lactamase-mediated resistance can be challenging, even for the infectious diseases specialist. AmpC resistance can be classified into 3 categories: (1) inducible chromosomal resistance that emerges in the setting of a β-lactam compound, (2) stable derepression due to mutations in ampC regulatory genes, or (3) the presence of plasmid-mediated ampC genes. This review will mainly focus on inducible AmpC resistance in Enterobacteriaceae. Although several observational studies have explored optimal treatment for AmpC producers, few provide reliable insights into effective management approaches. Heterogeneity within the data and inherent selection bias make inferences on effective β-lactam choices problematic. Most experts agree it is prudent to avoid expanded-spectrum (ie, third-generation) cephalosporins for the treatment of organisms posing the greatest risk of ampC induction, which has best been described in the context of Enterobacter cloacae infections. The role of other broad-spectrum β-lactams and the likelihood of ampC induction by other Enterobacteriaceae are less clear. We will review the mechanisms of resistance and triggers resulting in AmpC expression, the species-specific epidemiology of AmpC production, approaches to the detection of AmpC production, and treatment options for AmpC-producing infections.
Topics: Anti-Bacterial Agents; Bacterial Proteins; Drug Resistance, Bacterial; Enterobacter cloacae; Enterobacteriaceae; Enterobacteriaceae Infections; Humans; beta-Lactamases; beta-Lactams
PubMed: 30838380
DOI: 10.1093/cid/ciz173 -
Clinical Microbiology Reviews Dec 2019Surveillance studies have shown that OXA-48-like carbapenemases are the most common carbapenemases in in certain regions of the world and are being introduced on a... (Review)
Review
Surveillance studies have shown that OXA-48-like carbapenemases are the most common carbapenemases in in certain regions of the world and are being introduced on a regular basis into regions of nonendemicity, where they are responsible for nosocomial outbreaks. OXA-48, OXA-181, OXA-232, OXA-204, OXA-162, and OXA-244, in that order, are the most common enzymes identified among the OXA-48-like carbapenemase group. OXA-48 is associated with different Tn variants on IncL plasmids and is endemic in North Africa and the Middle East. OXA-162 and OXA-244 are derivatives of OXA-48 and are present in Europe. OXA-181 and OXA-232 are associated with IS, Tn on ColE2, and IncX3 types of plasmids and are endemic in the Indian subcontinent (e.g., India, Bangladesh, Pakistan, and Sri Lanka) and certain sub-Saharan African countries. Overall, clonal dissemination plays a minor role in the spread of OXA-48-like carbapenemases, but certain high-risk clones (e.g., sequence type 147 [ST147], ST307, ST15, and ST14 and ST38 and ST410) have been associated with the global dispersion of OXA-48, OXA-181, OXA-232, and OXA-204. Chromosomal integration of within Tn occurred among ST38 isolates, especially in the United Kingdom. The detection of with OXA-48-like enzymes using phenotypic methods has improved recently but remains challenging for clinical laboratories in regions of nonendemicity. Identification of the specific type of OXA-48-like enzyme requires sequencing of the corresponding genes. Bacteria (especially and ) with , , and are emerging in different parts of the world and are most likely underreported due to problems with the laboratory detection of these enzymes. The medical community should be aware of the looming threat that is posed by bacteria with OXA-48-like carbapenemases.
Topics: Clinical Laboratory Techniques; Enterobacteriaceae; Enterobacteriaceae Infections; Geography, Medical; Global Health; Humans; Molecular Diagnostic Techniques; Phylogeny; Public Health Surveillance; beta-Lactamases
PubMed: 31722889
DOI: 10.1128/CMR.00102-19 -
Clinics in Laboratory Medicine Jun 2017Carbapenem-resistant Enterobacteriaceae (CRE) have emerged as a major threat. Commonly used antibiotics are generally inactive against CRE. Therefore, timely detection... (Review)
Review
Carbapenem-resistant Enterobacteriaceae (CRE) have emerged as a major threat. Commonly used antibiotics are generally inactive against CRE. Therefore, timely detection of CRE is of paramount importance. Among CRE, those producing carbapenem-hydrolyzing β-lactamase enzymes (carbapenemase-producing Enterobacteriaceae) are particularly of concern because they tend to spread, and treatment is difficult. The carbapenemase groups most commonly encountered include KPC, NDM, and OXA-48. Treatment options are limited and include combinations of polymyxins, tigecycline, aminoglycosides, or carbapenems; newer agents with activity against CRE and better safety profiles are becoming available and will likely emerge as the preferred therapy.
Topics: Anti-Bacterial Agents; Carbapenems; Enterobacteriaceae; Microbial Sensitivity Tests; beta-Lactam Resistance; beta-Lactamases
PubMed: 28457352
DOI: 10.1016/j.cll.2017.01.005 -
Revista Chilena de Infectologia :... Jun 2022
Topics: Enterobacteriaceae; Enterobacteriaceae Infections; Humans
PubMed: 36156693
DOI: 10.4067/s0716-10182022000200319 -
Euro Surveillance : Bulletin Europeen... Feb 2018Background and aimPlasmid-mediated colistin resistance mechanisms have been identified worldwide in the past years. A multiplex polymerase chain reaction (PCR) protocol...
Background and aimPlasmid-mediated colistin resistance mechanisms have been identified worldwide in the past years. A multiplex polymerase chain reaction (PCR) protocol for detection of all currently known transferable colistin resistance genes ( to , and variants) in was developed for surveillance or research purposes. We designed four new primer pairs to amplify , , and gene products and used the originally described primers for to obtain a stepwise separation of ca 200 bp between amplicons. The primer pairs and amplification conditions allow for single or multiple detection of all currently described genes and their variants present in . The protocol was validated testing 49 European and isolates of animal origin. Multiplex PCR results in bovine and porcine isolates from Spain, Germany, France and Italy showed full concordance with whole genome sequence data. The method was able to detect and as singletons or in different combinations as they were present in the test isolates. One new variant, , was also identified. This method allows rapid identification of -positive bacteria and overcomes the challenges of phenotypic detection of colistin resistance. The multiplex PCR should be particularly interesting in settings or laboratories with limited resources for performing genetic analysis as it provides information on the mechanism of colistin resistance without requiring genome sequencing.
Topics: Anti-Bacterial Agents; Colistin; Enterobacteriaceae; Enterobacteriaceae Infections; Escherichia coli Proteins; Humans; Membrane Proteins; Microbial Sensitivity Tests; Multiplex Polymerase Chain Reaction; Plasmids; Salmonella; Transferases (Other Substituted Phosphate Groups)
PubMed: 29439754
DOI: 10.2807/1560-7917.ES.2018.23.6.17-00672 -
EcoSal Plus Jun 2019Plasmids are ubiquitous in the microbial world and have been identified in almost all species of bacteria that have been examined. Their localization inside the... (Review)
Review
Plasmids are ubiquitous in the microbial world and have been identified in almost all species of bacteria that have been examined. Their localization inside the bacterial cell has been examined for about two decades; typically, they are not randomly distributed, and their positioning depends on copy number and their mode of segregation. Low-copy-number plasmids promote their own stable inheritance in their bacterial hosts by encoding active partition systems, which ensure that copies are positioned in both halves of a dividing cell. High-copy plasmids rely on passive diffusion of some copies, but many remain clustered together in the nucleoid-free regions of the cell. Here we review plasmid localization and partition (Par) systems, with particular emphasis on plasmids from and on recent results describing the localization properties and molecular mechanisms of each system. Partition systems also cause plasmid incompatibility such that distinct plasmids (with different replicons) with the same Par system cannot be stably maintained in the same cells. We discuss how partition-mediated incompatibility is a consequence of the partition mechanism.
Topics: Bacterial Proteins; Enterobacteriaceae; Plasmids; Replicon
PubMed: 31187729
DOI: 10.1128/ecosalplus.ESP-0003-2019 -
Virologica Sinica Feb 2015The Enterobacteriaceae are a class of gram-negative facultative anaerobic rods, which can cause a variety of diseases, such as bacteremia, septic arthritis,... (Review)
Review
The Enterobacteriaceae are a class of gram-negative facultative anaerobic rods, which can cause a variety of diseases, such as bacteremia, septic arthritis, endocarditis, osteomyelitis, lower respiratory tract infections, skin and soft-tissue infections, urinary tract infections, intra-abdominal infections and ophthalmic infections, in humans, poultry, animals and fish. Disease caused by Enterobacteriaceae cause the deaths of millions of people every year, resulting in enormous economic loss. Drug treatment is a useful and efficient way to control Enterobacteriaceae infections. However, with the abuse of antibiotics, drug resistance has been found in growing number of Enterobacteriaceae infections and, as such, there is an urgent need to find new methods of control. Bacteriophage therapy is an efficient alternative to antibiotics as it employs a different antibacterial mechanism. This paper summarizes the history of bacteriophage therapy, its bacterial lytic mechanisms, and the studies that have focused on Enterobacteriaceae and bacteriophage therapy.
Topics: Animals; Bacteriophages; Biological Therapy; Enterobacteriaceae; Enterobacteriaceae Infections; History, 20th Century; History, 21st Century; Humans
PubMed: 25662887
DOI: 10.1007/s12250-014-3543-6 -
Nature Reviews. Microbiology Mar 2020Gram-negative bacteria and their complex cell envelope, which comprises an outer membrane and an inner membrane, are an important and attractive system for studying the... (Review)
Review
Gram-negative bacteria and their complex cell envelope, which comprises an outer membrane and an inner membrane, are an important and attractive system for studying the translocation of small molecules across biological membranes. In the outer membrane of Enterobacteriaceae, trimeric porins control the cellular uptake of small molecules, including nutrients and antibacterial agents. The relatively slow porin-mediated passive uptake across the outer membrane and active efflux via efflux pumps in the inner membrane creates a permeability barrier. The synergistic action of outer membrane permeability, efflux pump activities and enzymatic degradation efficiently reduces the intracellular concentrations of small molecules and contributes to the emergence of antibiotic resistance. In this Review, we discuss recent advances in our understanding of the molecular and functional roles of general porins in small-molecule translocation in Enterobacteriaceae and consider the crucial contribution of porins in antibiotic resistance.
Topics: Anti-Bacterial Agents; Bacterial Outer Membrane Proteins; Biological Transport; Cell Membrane; Drug Resistance, Bacterial; Enterobacteriaceae; Porins
PubMed: 31792365
DOI: 10.1038/s41579-019-0294-2 -
Antimicrobial Resistance and Infection... 2019OqxAB efflux pump has been found to mediate multidrug resistance (MDR) in various bacteria over the past decades. The updates on the nature and epidemiology of OqxAB... (Review)
Review
BACKGROUND
OqxAB efflux pump has been found to mediate multidrug resistance (MDR) in various bacteria over the past decades. The updates on the nature and epidemiology of OqxAB efflux pump need to be fully reviewed to broaden our understanding of this MDR determinant.
METHODS
A literature search using the keyword of "oqxAB" was conducted in the online databases of Pubmed and ISI Web of Science with no restriction on the date of publication. The 87 publications were included into this review as references due to their close relevance to the nature and/or epidemiology of OqxAB efflux pump.
RESULTS
The gene generally locates on chromosome and/or plasmids flanked by IS26-like elements in clinical isolates of and , conferring low to intermediated resistance to quinoxalines, quinolones tigecycline, nitrofurantoin, several detergents and disinfectants (benzalkonium chloride, triclosan and SDS). It could co-spread with other antimicrobial resistance genes (, and etc.), virulence genes and heavy metal resistance genes ( and operons). Both RarA (activator) and OqxR (repressor) play important roles on regulation of the expression of OqxAB.
CONCLUSIONS
The dissemination of gene may pose a great risk on food safety and public health. Further investigation and understanding of the natural functions, horizontal transfer, and regulation mechanism of the OqxAB efflux pump will aid in future strategies of antimicrobial usage.
Topics: Bacteria; Drug Resistance, Multiple, Bacterial; Enterobacteriaceae; Food Safety; Genes, Bacterial; Genes, MDR; Humans; Klebsiella pneumoniae; Plasmids; Public Health
PubMed: 30834112
DOI: 10.1186/s13756-019-0489-3 -
BMC Microbiology Dec 2022Acute Oak Decline (AOD) is a decline disease first reported on native oaks in the UK, but in recent years reports from further afield such as Europe and the Middle East,...
Description of a novel species of Leclercia, Leclercia tamurae sp. nov. and proposal of a novel genus Silvania gen. nov. containing two novel species Silvania hatchlandensis sp. nov. and Silvania confinis sp. nov. isolated from the rhizosphere of oak.
BACKGROUND
Acute Oak Decline (AOD) is a decline disease first reported on native oaks in the UK, but in recent years reports from further afield such as Europe and the Middle East, indicate that the distribution and host range is increasing at an alarming rate. The stem weeping symptoms of the disease partially develop due to polymicrobial-host interaction, caused by several members of the order Enterobacterales. While investigating the rhizosphere soil of AOD-unaffected trees, termed 'healthy' trees, and diseased oaks suffering from Acute Oak Decline (AOD), an enrichment method designed for enhanced recovery of Enterobacterales led to the recovery of several isolates that could not be classified as any existing species. These isolates showed a close relationship to the genus Leclercia, of which both species are of clinical importance, but the type species Leclercia adecarboxylata also displays plant growth-promoting properties in the rhizosphere.
RESULTS
Partial sequencing of four housekeeping genes revealed similarity to the genus Leclercia with varying degrees of relatedness. As such a complete polyphasic approach was used to determine the true taxonomic position of these isolates. This involved whole genome sequencing, phylogenomic analysis, phylogenetic analysis of both the 16S rRNA and four housekeeping gene sequences, combined with phenotypic testing and fatty acid analysis. Both the phylogenomic and phylogenetic analyses separated the isolates into four clusters, two of which were contained in the Leclercia clade. The remaining two clusters formed a separate lineage far removed from any currently defined species. Further investigation into the role of the isolates as plant growth-promoting bacteria as well as plant pathogens was investigated computationally, revealing a number of plant growth-promoting traits as well as virulence genes related to motility, adhesion and immune modulation.
CONCLUSION
Based on the genotypic and phenotypic data presented here, these isolates could be differentiated from each other and their closest neighbours. As such we propose the description of Leclercia tamurae sp. nov. (type strain H6S3 = LMG 32609 = CCUG 76176), Silvania gen. nov., Silvania hatchlandensis sp. nov. (type strain H19S6 = LMG 32608 = CCUG 76185) and Silvania confinis sp. nov. (type strain H4N4 = LMG 32607 = CCUG 76175). Due to their interesting protein annotations and alignments, these species warrant further investigation for their role in relation to plant health.
Topics: Quercus; Rhizosphere; Phylogeny; RNA, Ribosomal, 16S; Enterobacteriaceae; Gammaproteobacteria
PubMed: 36460957
DOI: 10.1186/s12866-022-02711-x