# | Rank | Similarity | Title + Abs. | Year | PMID |
|---|---|---|---|---|---|
| 0 | 1 | 2 | 3 | 4 | 5 |
| 4848 | 0 | 1.0000 | BioF is a novel B2 metallo-β-lactamase from Pseudomonas sp. isolated from an on-farm biopurification system. Antimicrobial resistance represents a major global health concern and environmental bacteria are considered a source of resistance genes. Carbapenems are often used as the last antibiotic option to treat multidrug-resistant bacteria. Metallo-β-lactamases (MBLs) are able to render resistance to almost all β-lactam antibiotics, including carbapenems. Unfortunately, there are no inhibitors against MBLs for clinical use. Subclass B2 MBLs are the only enzymes working as strict carbapenemases, under-represented, encoded in chromosome genes and only functional as mono-zinc enzymes. Despite current efforts in MBLs inhibitor development, B2 carbapenemase activity is especially difficult to suppress, even in vitro. In this study we characterized BioF, a novel subclass B2 MBL identified in a new environmental Pseudomonas sp. strain isolated from an on-farm biopurification system (BPS). Although bla(BioF) is most likely a chromosomal gene, it is found in a genomic island and may represent a step previous to the horizontal transmission of B2 genes. The new B2 MBL is active as a mono-zinc enzyme and is a potent carbapenemase with incipient activity against some cephalosporins. BioF activity is not affected by excess zinc and is only inhibited at high metal chelator concentrations. The discovery and characterization of B2 MBL BioF as a potent carbapenemase in a BPS bacterial isolate emphasizes the importance of exploring antibiotic resistances existing in the environmental microbiota under the influence of human activities before they could emerge clinically. | 2022 | 34725905 |
| 9932 | 1 | 0.9998 | Beta-lactam resistance mechanisms in gram-negative bacteria. Beta-lactam antibiotics are commonly used to treat a variety of bacterial infections. Gram-negative bacteria have evolved several resistance mechanisms including altered permeability and beta-lactamase production. New trends in resistance are emerging amongst clinical isolates which may reflect the choice of beta-lactam employed. | 1986 | 2856616 |
| 5022 | 2 | 0.9998 | HIV Drugs Inhibit Transfer of Plasmids Carrying Extended-Spectrum β-Lactamase and Carbapenemase Genes. Antimicrobial-resistant (AMR) infections pose a serious risk to human and animal health. A major factor contributing to this global crisis is the sharing of resistance genes between different bacteria via plasmids. The WHO lists Enterobacteriaceae, such as Escherichia coli and Klebsiella pneumoniae, producing extended-spectrum β-lactamases (ESBL) and carbapenemases as "critical" priorities for new drug development. These resistance genes are most often shared via plasmid transfer. However, finding methods to prevent resistance gene sharing has been hampered by the lack of screening systems for medium-/high-throughput approaches. Here, we have used an ESBL-producing plasmid, pCT, and a carbapenemase-producing plasmid, pKpQIL, in two different Gram-negative bacteria, E. coli and K. pneumoniae Using these critical resistance-pathogen combinations, we developed an assay using fluorescent proteins, flow cytometry, and confocal microscopy to assess plasmid transmission inhibition within bacterial populations in a medium-throughput manner. Three compounds with some reports of antiplasmid properties were tested; chlorpromazine reduced transmission of both plasmids and linoleic acid reduced transmission of pCT. We screened the Prestwick library of over 1,200 FDA-approved drugs/compounds. From this, we found two nucleoside analogue drugs used to treat HIV, abacavir and azidothymidine (AZT), which reduced plasmid transmission (AZT, e.g., at 0.25 μg/ml reduced pCT transmission in E. coli by 83.3% and pKpQIL transmission in K. pneumoniae by 80.8% compared to untreated controls). Plasmid transmission was reduced by concentrations of the drugs which are below peak serum concentrations and are achievable in the gastrointestinal tract. These drugs could be used to decolonize humans, animals, or the environment from AMR plasmids.IMPORTANCE More and more bacterial infections are becoming resistant to antibiotics. This has made treatment of many infections very difficult. One of the reasons this is such a large problem is that bacteria are able to share their genetic material with other bacteria, and these shared genes often include resistance to a variety of antibiotics, including some of our drugs of last resort. We are addressing this problem by using a fluorescence-based system to search for drugs that will stop bacteria from sharing resistance genes. We uncovered a new role for two drugs used to treat HIV and show that they are able to prevent the sharing of two different types of resistance genes in two unique bacterial strains. This work lays the foundation for future work to reduce the prevalence of resistant infections. | 2020 | 32098822 |
| 4844 | 3 | 0.9998 | Genetic basis of molecular mechanisms in β-lactam resistant gram-negative bacteria. Antibiotic-resistant bacteria are considered one of the major global threats to human and animal health. The most harmful among the resistant bacteria are β-lactamase producing Gram-negative species (β-lactamases). β-lactamases constitute a paradigm shift in the evolution of antibiotic resistance. Therefore, it is imperative to present a comprehensive review of the mechanisms responsible for developing antimicrobial resistance. Resistance due to β-lactamases develops through a variety of mechanisms, and the number of resistant genes are involved that can be transferred between bacteria, mostly via plasmids. Over time, these new molecular-based resistance mechanisms have been progressively disclosed. The present review article provides information on the recent findings regarding the molecular mechanisms of resistance to β-lactams in Gram-negative bacteria, including CTX-M-type ESBLs with methylase activity, plasmids harbouring phages with β-lactam resistance genes, the co-presence of β-lactam resistant genes of unique combinations and the presence of β-lactam and non-β-lactam antibiotic-resistant genes in the same bacteria. Keeping in view, the molecular level resistance development, multifactorial and coordinated measures may be taken to counter the challenge of rapidly increasing β-lactam resistance. | 2021 | 34119627 |
| 9928 | 4 | 0.9998 | The emergence and implications of metallo-beta-lactamases in Gram-negative bacteria. The increase in Gram-negative broad-spectrum antibiotic resistance is worrisome, particularly as there are few, if any, ''pipeline'' antimicrobial agents possessing suitable activity against Pseudomonas spp. or Acinetobacter spp. The increase in resistance will be further enhanced by the acquisition of metallo-beta-lactamase (MBL) genes that can potentially confer broad-spectrum beta-lactam resistance. These genes encode enzymes that can hydrolyse all classes of beta-lactams and the activity of which cannot be neutralised by beta-lactamase inhibitors. MBL genes are often associated with aminoglycoside resistant genes and thus bacteria that possess MBL genes are often co-resistant to aminoglycosides, further compromising therapeutic regimes. Both types of genes can be found as gene cassettes carried by integrons that in turn are embedded within transposons providing a highly ambulatory genetic element. The dissemination of MBL genes is typified by the spread of blaVIM-2, believed to originate from a Portuguese patient in 1995, and is now present in over 20 counties. The increase in international travel is likely to be a contributory factor for the ascendancy of mobile MBL genes as much as the mobility among individual bacteria. Fitness, acquisition and host dependency are key areas that need to be addressed to enhance our understanding of how antibiotic resistance spreads. There is also a pressing need for new, and hopefully novel, compounds active against pan-resistant Gram-negative bacteria--a growing problem that needs to be addressed by both government and industry. | 2005 | 16209700 |
| 4860 | 5 | 0.9997 | The rise of carbapenem-resistant Acinetobacter baumannii. Acinetobacter spp. are Gram-negative bacteria that have become one of the most difficult pathogens to treat. The species A. baumannii, largely unknown 30 years ago, has risen to prominence particularly because of its ability to cause infections in immunocompromised patients. It is now a predominant pathogen in many hospitals as it has acquired resistance genes to virtually all antibiotics capable of treating Gram-negative bacteria, including the fluoroquinolones and the cephalosporins. Some members of the species have accumulated these resistance genes in large resistance islands, located in a "hot-spot" within the bacterial chromosome. The only conventional remaining treatment options were the carbapenems. However, A. baumannii possesses an inherent class D β-lactamase gene (blaOXA-51-like) that can have the ability to confer carbapenem resistance. Additionally, mechanisms of carbapenem resistance have emerged that derive from the importation of the distantly related class D β-lactamase genes blaOXA-23 and blaOXA-58. Although not inducible, the expression of these genes is controlled by mobile promoters carried on ISAba elements. It has also been found that other resistance genes including the chromosomal class C β-lactamase genes conferring cephalosporin resistance are controlled in the same manner. Colistin is now considered to be the final drug capable of treating infections caused by carbapenem-resistant A. baumannii; however, strains are now being isolated that are resistant to this antibiotic as well. The increasing inability to treat infections caused by A. baumannii ensures that this pathogen more than ranks with MRSA or Clostridium difficile as a threat to modern medicine. | 2013 | 22894617 |
| 4845 | 6 | 0.9997 | The changing epidemiology of resistance. Antibiotic resistance is now a linked global problem. Dispersion of successful clones of multidrug resistant (MDR) bacteria is common, often via the movement of people. Local evolution of MDR bacteria is also important under the pressure of excessive antibiotic use, with horizontal gene transfer providing the means by which genes such as bla(CTX-M) spread amongst different bacterial species and strains. Beta-lactamase production is a common resistance mechanism in Gram-negative bacteria, and the rapid dissemination of novel genes reflects their evolution under the selective pressure of antibiotic usage. Many Enterobacteriaceae now carry broad-spectrum beta-lactamases such as CTX-M, with particular genotypes associated with different geographical regions. The spread of these enzymes has compromised the clinical utility of a number of beta-lactam classes and with the spread of genes such as bla(KPC), carbapenems may be increasingly compromised in the future. High-level fluoroquinolone resistance (mainly caused by gyrA mutations) has also been shown to be associated with CTX-M and CMY-type enzymes, commonly due to co-carriage on conjugative plasmids of the gene for the aminoglycoside-inactivating enzyme AAC-6(1)-Ib-cr and qnr genes (which confer low-level resistance), allowing the easy selection of gyrA mutants in the host strain. Resistance in Gram-positive bacteria is also widely distributed and increasing, with the emergence of community-associated methicillin-resistant Staphylococcus aureus (MRSA) blurring the distinction between hospital and community strains. Antibiotic use and environmental factors all have a role in the emergence and spread of resistance. This article reviews some of the new mechanisms and recent trends in the global spread of MDR bacteria. | 2009 | 19675017 |
| 4875 | 7 | 0.9997 | An Overview of the Genetic Mechanisms of Colistin-Resistance in Bacterial Pathogens: An Indian Perspective. Colistin resistance in bacteria is a growing global issue, given its role as a critical last-resort antibiotic, particularly for treating Gram-negative bacterial infections. Pathogens adopt multiple resistance mechanisms, mediated either by plasmids or chromosomal changes. Some of the most frequently observed strategies include the occurrence of plasmid-borne mobile colistin resistance (mcr) genes, enhanced efflux pump activity, mutations in the regulatory systems, and alterations in the lipid A structure. This article provides an overview of the studies investigating the genetic mechanisms underlying colistin resistance in nosocomial Gram-negative bacteria from India. A total of 37 studies were identified through online searches across various databases, including PubMed, ScienceDirect, and Web of Science. These studies were reviewed to examine bacterial species and their mechanisms of colistin resistance. Over 26 (70.27%) studies were focused on Klebsiella pneumoniae. The most commonly reported mechanism of colistin resistance involved mutations in the two-component systems pmrAB and phoPQ. Plasmid-mediated colistin-resistant mcr genes were identified in 22 studies (18.18%). Four studies reported the overexpression of efflux pump genes as a mechanism of colistin resistance. This article provides a comprehensive summary of these studies, emphasizing the presence of diverse resistance mechanisms across various pathogens. It underscores the necessity for future genomic research on a broader range of pathogens to investigate the prevalence of different mechanisms of colistin resistance in the various regions of India. | 2025 | 40078264 |
| 4839 | 8 | 0.9997 | beta-Lactamases: protein evolution in real time. The evolution and spread of bacteria resistant to beta-lactam antibiotics has progressed at an alarming rate. Bacteria may acquire resistance to a given drug by mutation of pre-existing genes or by the acquisition of new genes from other bacteria. One ongoing example of these mechanisms is the evolution of new variants of the TEM and SHV beta-lactamases with altered substrate specificity. | 1998 | 9746943 |
| 4843 | 9 | 0.9997 | The Efficacy of Isolated Bacteriophages from Pig Farms against ESBL/AmpC-Producing Escherichia coli from Pig and Turkey Farms. Extended-spectrum β-lactamases (ESBLs) and AmpC β-lactamases are plasmid (but also chromosomally) encoded enzymes found in Enterobacteriaceae, determining resistance to a variety of important antibiotics including penicillins, cephalosporins, and monobactams. In recent decades, the prevalence of ESBL/AmpC-producing bacteria has increased rapidly across the world. Here, we evaluate the potential use of bacteriophages in terms of a reduction of antibiotic-resistant bacteria in healthy animals. The aim of our studies was to isolate bacteriophages capable of destroying ESBL/AmpC-producing Escherichia coli isolated from livestock habitats. The efficacy of isolated phages against ESBL/AmpC E. coli strains varies, but creation of a phage cocktail with broad activity spectrum is possible. This may indicate that the role of phages may not be limited to phage therapy, but bacterial viruses may also be applied against spread of bacteria with antibiotic resistance genes in the environment. We also addressed the hypothesis, that phages, effective for therapeutic purposes may be isolated from distant places and even from different environments other than the actual location of the targeted bacteria. This may be beneficial for practical purposes, as the construction of effective phage preparations does not require access to disease outbreaks. | 2017 | 28405193 |
| 4863 | 10 | 0.9997 | Carbapenem Resistance in Gram-Negative Bacteria: The Not-So-Little Problem in the Little Red Dot. Singapore is an international travel and medical hub and faces a genuine threat for import and dissemination of bacteria with broad-spectrum resistance. In this review, we described the current landscape and management of carbapenem resistance in Gram-negative bacteria (GNB) in Singapore. Notably, the number of carbapenem-resistant Enterobacteriaceae has exponentially increased in the past two years. Resistance is largely mediated by a variety of mechanisms. Polymyxin resistance has also emerged. Interestingly, two Escherichia coli isolates with plasmid-mediated mcr-1 genes have been detected. Evidently, surveillance and infection control becomes critical in the local setting where resistance is commonly related to plasmid-mediated mechanisms, such as carbapenemases. Combination antibiotic therapy has been proposed as a last-resort strategy in the treatment of extensively drug-resistant (XDR) GNB infections, and is widely adopted in Singapore. The diversity of carbapenemases encountered, however, presents complexities in both carbapenemase detection and the selection of optimal antibiotic combinations. One unique strategy introduced in Singapore is a prospective in vitro combination testing service, which aids physicians in the selection of individualized combinations. The outcome of this treatment strategy has been promising. Unlike countries with a predominant carbapenemase type, Singapore has to adopt management strategies which accounts for diversity in resistance mechanisms. | 2016 | 27681907 |
| 4857 | 11 | 0.9997 | The emergence of bacterial resistance and its influence on empiric therapy. The discovery of antimicrobial agents had a major impact on the rate of survival from infections. However, the changing patterns of antimicrobial resistance caused a demand for new antibacterial agents. Within a few years of the introduction of penicillin, the majority of staphylococci were resistant to that drug. In the 1960s the production of the semisynthetic penicillins provided an answer to the problem of staphylococcal resistance. In the early 1960s most Escherichia coli were susceptible to the new beta-lactam antibiotic ampicillin; by the end of that decade, plasmid-mediated beta-lactamase resistance was found in 30%-50% of hospital-acquired E. coli. Use of certain agents resulted in the selection of bacteria, such as Klebsiella, that are intrinsically resistant to ampicillin. The original cephalosporins were stable to beta-lactamase, but the use of these agents was in part responsible for the appearance of infections due to Enterobacter species, Citrobacter species, and Pseudomonas aeruginosa. These bacteria, as well as Serratia, were resistant to many of the available beta-lactam agents. Aminoglycosides initially provided excellent activity against most of the facultative gram-negative bacteria. However, the widespread dissemination of the genes that cause production of the aminoglycoside-inactivating enzymes altered the use of those agents. Clearly, the evolution of bacterial resistance has altered the prescribing patterns for antimicrobial agents. Knowledge that beta-lactam resistance to ampicillin or cephalothin is prevalent is causing physicians to select as empiric therapy either a combination of two or more agents or agents to which resistance is uncommon. The new cephalosporins offer a broad spectrum of anti-bacterial activity coupled with low toxicity. However, physicians must closely follow the changing ecology of bacteria when these agents are used, because cephalosporins can also select bacteria resistant to themselves and thereby abolish their value as empiric therapy. | 1983 | 6342103 |
| 4864 | 12 | 0.9997 | Colistin resistance mechanisms in Gram-negative bacteria: a Focus on Escherichia coli. Multidrug-resistant (MDR) Escherichia coli strains have rapidly increased worldwide, and effective antibiotic therapeutic options are becoming more restricted. As a polymyxin antibiotic, colistin has a long history of usage, and it is used as a final line of treatment for severe infections by Gram-negative bacteria (GNB) with high-level resistance. However, its application has been challenged by the emergence of E. coli colistin resistance. Hence, determining the mechanism that confers colistin resistance is crucial for monitoring and controlling the dissemination of colistin-resistant E. coli strains. This comprehensive review summarizes colistin resistance mechanisms in E. coli strains and concentrates on the history, mode of action, and therapeutic implications of colistin. We have mainly focused on the fundamental mechanisms of colistin resistance that are mediated by chromosomal or plasmid elements and discussed major mutations in the two-component systems (TCSs) genes and plasmids that transmit the mobilized colistin resistance resistant genes in E. coli strains. | 2023 | 36754367 |
| 1548 | 13 | 0.9997 | Metallo-beta-lactamases of Pseudomonas aeruginosa--a novel mechanism resistance to beta-lactam antibiotics. Since about twenty years, following the introduction into therapeutic of news beta-lactam antibiotics (broad-spectrum cephalosporins, monobactams and carbapenems), a very significant number of new beta-lactamases appeared. These enzymes confer to the bacteria which put them, the means of resisting new molecules. The genetic events involved in this evolution are of two types: evolution of old enzymes by mutation and especially appearance of new genes coming for some, from bacteria of the environment. Numerous mechanisms of enzymatic resistance to the carbapenems have been described in Pseudomonas aeruginosa. The important mechanism of inactivation carbapenems is production variety of b-lactam hydrolysing enzymes associated to carbapenemases. The metallo-beta-enzymes (IMP, VIM, SPM, GIM types) are the most clinically significant carbapenemases. P. aeruginosa posses MBLs and seem to have acquired them through transmissible genetic elements (plasmids or transposons associated with integron) and can be transmission to other bacteria. They have reported worldwide but mostly from South East Asia and Europe. The enzymes, belonging to the molecular class B family, are the most worrisome of all beta-lactamases because they confer resistance to carbapenems and all the beta-lactams (with the exception of aztreonam) and usually to aminoglycosides and quinolones. The dissemination of MBLs genes is thought to be driven by regional consumption of extended--spectrum antibiotics (e.g. cephalosporins and carbapenems), and therefore care must be taken that these drugs are not used unnecessarily. | 2008 | 18519228 |
| 4861 | 14 | 0.9997 | The Challenge of Global Emergence of Novel Colistin-Resistant Escherichia coli ST131. Escherichia coli ST131 is one of the high-risk multidrug-resistant clones with a global distribution and the ability to persist and colonize in a variety of niches. Carbapenemase-producing E. coli ST131 strains with the ability to resist last-line antibiotics (i.e., colistin) have been recently considered a significant public health. Colistin is widely used in veterinary medicine and therefore, colistin-resistant bacteria can be transmitted from livestock to humans through food. There are several mechanisms of resistance to colistin, which include chromosomal mutations and plasmid-transmitted mcr genes. E. coli ST131 is a great model organism to investigate the emergence of superbugs. This microorganism has the ability to cause intestinal and extraintestinal infections, and its accurate identification as well as its antibiotic resistance patterns are vitally important for a successful treatment strategy. Therefore, further studies are required to understand the evolution of this resistant organism for drug design, controlling the evolution of other nascent emerging pathogens, and developing antibiotic stewardship programs. In this review, we will discuss the importance of E. coli ST131, the mechanisms of resistance to colistin as the last-resort antibiotic against resistant Gram-negative bacteria, reports from different regions regarding E. coli ST131 resistance to colistin, and the most recent therapeutic approaches against colistin-resistance bacteria. | 2021 | 33913748 |
| 4862 | 15 | 0.9997 | Genetic Factors That Contribute to Antibiotic Resistance through Intrinsic and Acquired Bacterial Genes in Urinary Tract Infections. The overprescribing and misuse of antibiotics have led to the rapid development of multidrug-resistant bacteria, such as those that cause UTIs. UTIs are the most common outpatient infections and are mainly caused by Escherichia coli and Klebsiella spp., although some Gram-positive bacteria, such as Pseudomonas aeruginosa, have been isolated in many cases. The rise of antimicrobial-resistant bacteria is a major public health concern, as it is predicted to lead to increased healthcare costs and poor patient outcomes and is expected to be the leading cause of global mortality by 2050. Antibiotic resistance among bacterial species can arise from a myriad of factors, including intrinsic and acquired resistance mechanisms, as well as mobile genetic elements, such as transposons, integrons, and plasmids. Plasmid-mediated resistance is of major concern as drug-resistance genes can quickly and efficiently spread across bacterial species via horizontal gene transfer. The emergence of extended-spectrum β-lactamases (ESBLs) such as NDM-1, OXA, KPC, and CTX-M family members has conferred resistance to many commonly used antibiotics in the treatment of UTIs, including penicillins, carbapenems, cephalosporins, and sulfamethoxazole. This review will focus on plasmid-mediated bacterial genes, especially those that encode ESBLs, and how they contribute to antibiotic resistance. Early clinical detection of these genes in patient samples will provide better treatment options and reduce the threat of antibiotic resistance. | 2023 | 37374909 |
| 4846 | 16 | 0.9997 | Mobile fosfomycin resistance genes in Enterobacteriaceae-An increasing threat. Antimicrobial resistance is one of the major threats to the health and welfare of both humans and animals. The shortage of new antimicrobial agents has led to the re-evaluation of old antibiotics such as fosfomycin as a potential regimen for treating multidrug-resistant bacteria especially extended-spectrum-beta-lactamase- and carbapenemase-producing Enterobacteriaceae. Fosfomycin is a broad-spectrum bactericidal antibiotic that inhibits the initial step of the cell wall biosynthesis. Fosfomycin resistance can occur due to mutation in the drug uptake system or by the acquisition of fosfomycin-modifying enzymes. In this review, we focus on mobile fosfomycin-resistant genes encoding glutathione-S-transferase which are mainly responsible for fosfomycin resistance in Enterobacteriaceae, that is, fosA and its subtypes, fosC2, and the recently described fosL1-L2. We summarized the proposed origins of the different resistance determinants and highlighted the different plasmid types which are attributed to the dissemination of fosfomycin-modifying enzymes. Thereby, IncF and IncN plasmids play a predominant role. The detection of mobile fosfomycin-resistant genes in Enterobacteriaceae has increased in recent years. Similar to the situation in (East) Asia, the most frequently detected fosfomycin-resistant gene in Europe is fosA3. Mobile fosfomycin-resistant genes have been detected in isolates of human, animal, food, and environmental origin which leads to a growing concern regarding the risk of spread of such bacteria, especially Escherichia coli and Salmonella, at the human-animal-environment interface. | 2020 | 33128341 |
| 5028 | 17 | 0.9997 | The Current Burden of Carbapenemases: Review of Significant Properties and Dissemination among Gram-Negative Bacteria. Carbapenemases are β-lactamases belonging to different Ambler classes (A, B, D) and can be encoded by both chromosomal and plasmid-mediated genes. These enzymes represent the most potent β-lactamases, which hydrolyze a broad variety of β-lactams, including carbapenems, cephalosporins, penicillin, and aztreonam. The major issues associated with carbapenemase production are clinical due to compromising the activity of the last resort antibiotics used for treating serious infections, and epidemiological due to their dissemination into various bacteria across almost all geographic regions. Carbapenemase-producing Enterobacteriaceae have received more attention upon their first report in the early 1990s. Currently, there is increased awareness of the impact of nonfermenting bacteria, such as Acinetobacter baumannii and Pseudomonas aeruginosa, as well as other Gram-negative bacteria that are carbapenemase-producers. Outside the scope of clinical importance, carbapenemases are also detected in bacteria from environmental and zoonotic niches, which raises greater concerns over their prevalence, and the need for public health measures to control consequences of their propagation. The aims of the current review are to define and categorize the different families of carbapenemases, and to overview the main lines of their spread across different bacterial groups. | 2020 | 32316342 |
| 9931 | 18 | 0.9997 | New beta-lactamases in gram-negative bacteria: diversity and impact on the selection of antimicrobial therapy. Of the 340 discrete beta-lactamases that have been identified, the most important groups of enzymes that are continuing to proliferate include the plasmid-encoded cephalosporinases, the metallo-beta-lactamases, and the extended-spectrum beta-lactamases. Resistance to specific beta-lactam-containing antimicrobial agents frequently can be traced to a single beta-lactamase, but this task is becoming more difficult for the clinical microbiology laboratory. Other factors, such as multiple beta-lactamase production, transferable multidrug-resistance genes, alterations in outer-membrane porins, and possible antibiotic efflux, all may contribute to a resistance phenotype. Appreciation of these factors may help the physician make a more informed decision when choosing therapy to try to avoid selection of even more pathogenic strains. | 2001 | 11264037 |
| 4923 | 19 | 0.9997 | Genetic Resistance Determinants in Clinical Acinetobacter pittii Genomes. Antimicrobial-resistant pathogenic bacteria are an increasing problem in public health, especially in the healthcare environment, where nosocomial infection microorganisms find their niche. Among these bacteria, the genus Acinetobacter which belongs to the ESKAPE pathogenic group harbors different multi-drug resistant (MDR) species that cause human nosocomial infections. Although A. baumannii has always attracted more interest, the close-related species A. pittii is the object of more study due to the increase in its isolation and MDR strains. In this work, we present the genomic analysis of five clinically isolated A. pittii strains from a Spanish hospital, with special attention to their genetic resistance determinants and plasmid structures. All the strains harbored different genes related to β-lactam resistance, as well as different MDR efflux pumps. We also found and described, for the first time in this species, point mutations that seem linked with colistin resistance, which highlights the relevance of this comparative analysis among the pathogenic species isolates. | 2022 | 35625320 |