# | Rank | Similarity | Title + Abs. | Year | PMID |
|---|---|---|---|---|---|
| 0 | 1 | 2 | 3 | 4 | 5 |
| 5047 | 0 | 1.0000 | Phenotypic and Genotypic Characterization of Pan-Drug-Resistant Klebsiella pneumoniae Isolated in Qatar. In secondary healthcare, carbapenem-resistant Enterobacterales (CREs), such as those observed in Klebsiella pneumoniae, are a global public health priority with significant clinical outcomes. In this study, we described the clinical, phenotypic, and genotypic characteristics of three pan-drug-resistant (PDR) isolates that demonstrated extended resistance to conventional and novel antimicrobials. All patients had risk factors for the acquisition of multidrug-resistant organisms, while microbiological susceptibility testing showed resistance to all conventional antimicrobials. Advanced susceptibility testing demonstrated resistance to broad agents, such as ceftazidime-avibactam, ceftolozane-tazobactam, and meropenem-vaborbactam. Nevertheless, all isolates were susceptible to cefiderocol, suggested as one of the novel antimicrobials that demonstrated potent in vitro activity against resistant Gram-negative bacteria, including CREs, pointing toward its potential therapeutic role for PDR pathogens. Expanded genomic studies revealed multiple antimicrobial-resistant genes (ARGs), including bla(NMD-5) and bla(OXA) derivative types, as well as a mutated outer membrane porin protein (OmpK37). | 2024 | 38534710 |
| 1556 | 1 | 0.9998 | Resistance to Colistin in Klebsiella Pneumoniae: A 4.0 Strain? The global rise of multidrug-resistant gram-negative bacteria represents an increasing threat to patient safety. From the first observation of a carbapenem-resistant gram-negative bacteria a global spread of extended-spectrum beta-lactamases and carbapenemases producing Klebsiella pneumoniae has been observed. Treatment options for multidrug-resistant K. pneumoniae are actually limited to combination therapy with some aminoglycosides, tigecycline and to older antimicrobial agents. Unfortunately, the prevalence of colistin-resistant and tigecycline-resistant K. pneumoniae is increasing globally. Infection due to colistin-resistant K. pneumoniae represents an independent risk factor for mortality. Resistance to colistin in K. pneumoniae may be multifactorial, as it is mediated by chromosomal genes or plasmids. The emergence of transmissible, plasmid-mediated colistin resistance is an alarming finding. The absence of new agents effective against resistant Gram-negative pathogens means that enhanced surveillance, compliance with infection prevention procedures, and antimicrobial stewardship programs will be required to limit the spread of colistin-resistant K. pneumoniae. | 2017 | 28626539 |
| 5046 | 2 | 0.9997 | Molecular mechanisms of colistin- and multidrug-resistance in bacteria among patients with hospital-acquired infections. AIM: The increasing burden of resistance in Gram-negative bacteria (GNB) is becoming a major issue for hospital-acquired infections. Therefore, understanding the molecular mechanisms is important. METHODOLOGY: Resistance genes of phenotypically colistin-resistant GNB (n = 60) were determined using whole genome sequencing. Antimicrobial susceptibility patterns were detected by Vitek®2 & broth microdilution. RESULTS: Of these phenotypically colistin-resistant isolates, 78% were also genetically resistant to colistin. Activation of efflux pumps, and point-mutations in pmrB, and MgrB genes conferred colistin resistance among GNB. Eight different strains of K. pneumoniae were identified and ST43 was the most prominent strain with capsular type-specific (cps) gene KL30. DISCUSSION: These results, in combination with rapid diagnostic methods, will help us better advice appropriate antimicrobial regimens. | 2023 | 37753358 |
| 1551 | 3 | 0.9997 | Mechanisms of Resistance in Gram-Negative Urinary Pathogens: From Country-Specific Molecular Insights to Global Clinical Relevance. Urinary tract infections (UTIs) are the most frequent hospital infections and among the most commonly observed community acquired infections. Alongside their clinical importance, they are notorious because the pathogens that cause them are prone to acquiring various resistance determinants, including extended-spectrum beta-lactamases (ESBL); plasmid-encoded AmpC β-lactamases (p-AmpC); carbapenemases belonging to class A, B, and D; qnr genes encoding reduced susceptibility to fluoroquinolones; as well as genes encoding enzymes that hydrolyse aminoglycosides. In Escherichia coli and Klebsiella pneumoniae, the dominant resistance mechanisms are ESBLs belonging to the CTX-M, TEM, and SHV families; p-AmpC; and (more recently) carbapenemases belonging to classes A, B, and D. Urinary Pseudomonas aeruginosa isolates harbour metallo-beta-lactamases (MBLs) and ESBLs belonging to PER and GES families, while carbapenemases of class D are found in urinary Acinetobacter baumannii isolates. The identification of resistance mechanisms in routine diagnostic practice is primarily based on phenotypic tests for the detection of beta-lactamases, such as the double-disk synergy test or Hodge test, while polymerase chain reaction (PCR) for the detection of resistance genes is mostly pursued in reference laboratories for research purposes. As the emergence of drug-resistant bacterial strains poses serious challenges in the management of UTIs, this review aimed to appraise mechanisms of resistance in relevant Gram-negative urinary pathogens, to provide a detailed map of resistance determinants in Croatia and the world, and to discuss the implications of these resistance traits on diagnostic approaches. We summarized a sundry of different resistance mechanisms among urinary isolates and showed how their prevalence highly depends on the local epidemiological context, highlighting the need for tailored interventions in the field of antimicrobial stewardship. | 2021 | 33925181 |
| 5700 | 4 | 0.9997 | Gram-negative bacterial colonization in the gut: Isolation, characterization, and identification of resistance mechanisms. BACKGROUND: The gut microbiome is made up of a diverse range of bacteria, especially gram-negative bacteria, and is crucial for human health and illness. There is a great deal of interest in the dynamic interactions between gram-negative bacteria and their host environment, especially considering antibiotic resistance. This work aims to isolate gram-negative bacteria that exist in the gut, identify their species, and use resistance-associated gene analysis to define their resistance mechanisms. METHODS: Samples were collected from all patients who had a stool culture at a tertiary care center in Lebanon. Each type of bacteria that was identified from the stool samples was subjected to critical evaluations, and all discovered strains underwent antimicrobial susceptibility testing. Polymerase chain reaction was used to profile the genes for Carbapenem-resistant Enterobacteriaceae (CRE), Extended-spectrum beta-lactamase (ESBL), and that of Pseudomonas aeruginosa strains. RESULTS: Escherichia coli, Klebsiella species, and Pseudomonas aeruginosa turned out to be the predominant microbiota members. Escherichia coli strains had a high frequency of extended-spectrum beta-lactamase genes, with the most discovered gene being bla CTX-M. Additionally, a considerable percentage of isolates had carbapenemase-resistant Enterobacteriaceae genes, suggesting the rise of multidrug-resistant strains. Multidrug resistance genes, such as bla mexR, bla mexB, and bla mexA, were found in strains of Pseudomonas aeruginosa, highlighting the possible difficulties in treating infections brought on by these bacteria. CONCLUSION: The findings highlight the critical importance of effective surveillance and response measures to maintain the effectiveness of antibiotics considering the introduction of multidrug resistance genes in Pseudomonas aeruginosa and ESBL and CRE genes in Escherichia coli. | 2024 | 39216133 |
| 2264 | 5 | 0.9997 | Assessment of three antibiotic combination regimens against Gram-negative bacteria causing neonatal sepsis in low- and middle-income countries. Gram-negative bacteria (GNB) are a major cause of neonatal sepsis in low- and middle-income countries (LMICs). Although the World Health Organization (WHO) reports that over 80% of these sepsis deaths could be prevented through improved treatment, the efficacy of the currently recommended first- and second-line treatment regimens for this condition is increasingly affected by high rates of drug resistance. Here we assess three well known antibiotics, fosfomycin, flomoxef and amikacin, in combination as potential antibiotic treatment regimens by investigating the drug resistance and genetic profiles of commonly isolated GNB causing neonatal sepsis in LMICs. The five most prevalent bacterial isolates in the NeoOBS study (NCT03721302) are Klebsiella pneumoniae, Acinetobacter baumannii, E. coli, Serratia marcescens and Enterobacter cloacae complex. Among these isolates, high levels of ESBL and carbapenemase encoding genes are detected along with resistance to ampicillin, gentamicin and cefotaxime, the current WHO recommended empiric regimens. The three new combinations show excellent in vitro activity against ESBL-producing K. pneumoniae and E. coli isolates. Our data should further inform and support the clinical evaluation of these three antibiotic combinations for the treatment of neonatal sepsis in areas with high rates of multidrug-resistant Gram-negative bacteria. | 2024 | 38729951 |
| 2515 | 6 | 0.9997 | High-risk Pseudomonas aeruginosa clones harboring β-lactamases: 2024 update. Carbapenem-resistant Pseudomonas aeruginosa is defined by the World Health Organization as a "high priority" in developing new antimicrobials. Indeed, the emergence and spread of multidrug-resistant (MDR) or extensively drug-resistant (XDR) bacteria increase the morbidity and mortality risk of infected patients. Genomic variants of P. aeruginosa that display phenotypes of MDR/XDR have been defined as high-risk global clones. In this mini-review, we describe some international high-risk clones that carry β-lactamase genes that can produce chronic colonization and increase infected patients' morbidity and mortality rates. | 2025 | 39850428 |
| 1571 | 7 | 0.9997 | Klebsiella pneumoniae ST147 harboring bla(NDM-1), multidrug resistance and hypervirulence plasmids. The spread of hypervirulent (hv) and carbapenem-/multidrug-resistant Klebsiella pneumoniae is an emerging problem in healthcare settings. The New Delhi metallo-β-lactamase-1 (bla(NDM-1)) is found in Enterobacteriaceae including K. pneumoniae. The bla(NDM-1) is capable of hydrolyzing β-lactam antibiotics which are used for treatment of severe infections caused by multidrug-resistant Gram-negative bacteria. This is associated with the unacceptably high mortality rate in immunocompromised burn injury patients. This study reports on the characterization of bla(NDM-1) gene and virulence factors in hv carbapenem-/multidrug-resistant K. pneumoniae ST147 in the burns unit of a tertiary teaching hospital during routine surveillance. Two K. pneumoniae strains were obtained from wounds of burn-infected patients from May 2020 to July 2021. The hypervirulence genes and genetic context of the bla(NDM-1) gene and mobile genetic elements potentially involved in the transposition of the gene were analyzed. We identified a conserved genetic background and an IS26 and open reading frame flanking the bla(NDM-1) gene that could suggest its involvement in the mobilization of the gene. The plasmid harbored additional antibiotic resistance predicted regions that were responsible for resistance to almost all the routinely used antibiotics. To ensure the identification of potential outbreak strains during routine surveillance, investigations on resistance genes and their environment in relation to evolution are necessary for molecular epidemiology.IMPORTANCEData obtained from this study will aid in the prompt identification of disease outbreaks including evolving resistance and virulence of the outbreak bacteria. This will help establish and implement antimicrobial stewardship programs and infection prevention protocols in fragile health systems in countries with limited resources. Integration of molecular surveillance and translation of whole-genome sequencing in routine diagnosis will provide valuable data for control of infection. This study reports for the first time a high-risk clone K. pneumoniae ST147 with hypervirulence and multidrug-resistance features in Ghana. | 2024 | 38315028 |
| 1574 | 8 | 0.9997 | Plethora of Resistance Genes in Carbapenem-Resistant Gram-Negative Bacteria in Greece: No End to a Continuous Genetic Evolution. Carbapenem-resistant Gram-negative bacteria are a public health threat that requires urgent action. The fact that these pathogens commonly also harbor resistance mechanisms for several other antimicrobial classes further reduces patient treatment options. The present study aimed to provide information regarding the multidrug resistance genetic background of carbapenem-resistant Gram-negative bacteria in Central Greece. Strains from a tertiary care hospital, collected during routine practice, were characterized using a DNA microarray-based assay. Various different resistance determinants for carbapenems, other beta-lactams, aminoglycosides, quinolones, trimethoprim, sulfonamides and macrolides were detected among isolates of the same sequence type. Eighteen different multidrug resistance genomic profiles were identified among the twenty-four K. pneumoniae ST258, seven different profiles among the eight K. pneumoniae ST11, four profiles among the six A. baumannii ST409 and two among the three K. oxytoca. This report describes the multidrug resistance genomic background of carbapenem-resistant Gram-negative bacteria from a tertiary care hospital in Central Greece, providing evidence of their continuous genetic evolution. | 2022 | 35056608 |
| 1552 | 9 | 0.9997 | Evolution of β-Lactam Antibiotic Resistance in Proteus Species: From Extended-Spectrum and Plasmid-Mediated AmpC β-Lactamases to Carbapenemases. The management of infectious diseases has proven to be a daunting task for clinicians worldwide, and the rapid development of antibiotic resistance among Gram-negative bacteria is making it even more challenging. The first-line therapy is empirical, and it most often comprises β-lactam antibiotics. Among Gram-negative bacteria, Proteus mirabilis, an important community and hospital pathogen associated primarily with urinary tract and wound infection, holds a special place. This review's aim was to collate and examine recent studies investigating β-lactam resistance phenotypes and mechanisms of Proteus species and the global significance of its β-lactam resistance evolution. Moreover, the genetic background of resistance traits and the role of mobile genetic elements in the dissemination of resistance genes were evaluated. P. mirabilis as the dominant pathogen develops resistance to expanded-spectrum cephalosporins (ESC) by producing extended-spectrum β-lactamases (ESBL) and plasmid-mediated AmpC β-lactamases (p-AmpC). β-lactamase-mediated resistance to carbapenems in Enterobacterales, including Proteus spp., is mostly due to expression of carbapenemases of class A (KPC); class B (metallo-β-lactamases or MBLs of IMP, VIM, or NDM series); or class D or carbapenem-hydrolyzing oxacillinases (CHDL). Previously, a dominant ESBL type in P. mirabilis was TEM-52; yet, lately, it has been replaced by CTX-M variants, particularly CTX-M-14. ESC resistance can also be mediated by p-AmpC, with CMY-16 as the dominant variant. Carbapenem resistance in Proteus spp. is a challenge due to its intrinsic resistance to colistin and tigecyclin. The first carbapenemases reported belonged to class B, most frequently VIM-1 and NDM-5. In Europe, predominantly France and Belgium, a clonal lineage positive for OXA-23 CHDL spreads rapidly undetected, due to its low-level resistance to carbapenems. The amazing capacity of Proteus spp. to accumulate a plethora of various resistance traits is leading to multidrug or extensively drug-resistant phenotypes. | 2025 | 40142401 |
| 1572 | 10 | 0.9997 | Phenotypic and Genomic Characterization of AmpC-Producing Klebsiella pneumoniae From Korea. The prevalence of multidrug-resistant gram-negative bacteria has continuously increased over the past few years; bacterial strains producing AmpC β-lactamases and/or extended-spectrum β-lactamases (ESBLs) are of particular concern. We combined high-resolution whole genome sequencing and phenotypic data to elucidate the mechanisms of resistance to cephamycin and β-lactamase in Korean Klebsiella pneumoniae strains, in which no AmpC-encoding genes were detected by PCR. We identified several genes that alone or in combination can potentially explain the resistance phenotype. We showed that different mechanisms could explain the resistance phenotype, emphasizing the limitations of the PCR and the importance of distinguishing closely-related gene variants. | 2018 | 29611388 |
| 1579 | 11 | 0.9997 | Inverse Association between the Existence of CRISPR/Cas Systems with Antibiotic Resistance, Extended Spectrum β-Lactamase and Carbapenemase Production in Multidrug, Extensive Drug and Pandrug-Resistant Klebsiella pneumoniae. Antimicrobial resistance, with the production of extended-spectrum β-lactamases (ESBL) and carbapenemases, is common in the opportunistic pathogen, Klebsiella pneumoniae. This organism has a genome that can contain clustered regularly interspaced short palindromic repeats (CRISPRs), which operate as a defense mechanism against external invaders such as plasmids and viruses. This study aims to determine the association of the CRISPR/Cas systems with antibiotic resistance in K. pneumoniae isolates from Iraqi patients. A total of 100 K. pneumoniae isolates were collected and characterized according to their susceptibility to different antimicrobial agents. The CRISPR/Cas systems were detected via PCR. The phenotypic detection of ESBLs and carbapenemases was performed. The production of ESBL was detected in 71% of the isolates. Carbapenem-resistance was detected in 15% of the isolates, while only 14% were susceptible to all antimicrobial agents. Furthermore, the bacteria were classified into multidrug (77%), extensively drug-resistant (11.0%) and pandrug-resistant (4.0%). There was an inverse association between the presence of the CRISPR/Cas systems and antibiotic resistance, as resistance was higher in the absence of the CRISPR/Cas system. Multidrug resistance in ESBL-producing and carbapenem-resistant K. pneumoniae occurred more frequently in strains negative for the CRISPR/Cas system. Thus, we conclude that genes for exogenous antibiotic resistance can be acquired in the absence of the CRISPR/Cas modules that can protect the bacteria against acquiring foreign DNA. | 2023 | 37370299 |
| 1666 | 12 | 0.9997 | Detection of PhoP-mediated colistin resistance in Gram-negative bacteria without mcr genes in human population in the Ho Municipality, Ghana. INTRODUCTION: Antimicrobial resistance (AMR) has become a global public health threat, with colistin emerging as a last-resort treatment option for multidrug-resistant Gram-negative infections. However, the emergence of colistin resistance, mediated by mechanisms like mutations in the PhoP gene, raises concerns about the future utility of this antibiotic. This study aimed to determine the prevalence of PhoP-mediated colistin resistance in Gram-negative bacteria isolated from the stool of residents in the Ho Municipality, Ghana. METHODS: In this cross-sectional study, 110 stool samples were collected from June 2021 to December 2022. Gram-negative bacteria were isolated, and colistin susceptibility was determined by broth microdilution. Genomic DNA from resistant isolates was extracted and sequenced using the Nanopore platform to detect the presence of the PhoP gene. RESULTS: Of the 107 Gram-negative isolates, 57 % were resistant to colistin. The PhoP gene was detected in 61.4 % of the colistin-resistant isolates, with the highest prevalence observed in Proteus mirabilis, Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae. CONCLUSION: The study reveals a high prevalence of PhoP-mediated colistin resistance among Gram-negative bacteria colonizing residents in the Ho Municipality, highlighting the role of the gut microbiota as a reservoir for antibiotic resistance. Continued surveillance and a collaborative One Health approach are crucial to address this growing threat. | 2024 | 39524735 |
| 1573 | 13 | 0.9997 | Genomic Analysis of a Pan-Resistant Isolate of Klebsiella pneumoniae, United States 2016. Antimicrobial resistance is a threat to public health globally and leads to an estimated 23,000 deaths annually in the United States alone. Here, we report the genomic characterization of an unusual Klebsiella pneumoniae, nonsusceptible to all 26 antibiotics tested, that was isolated from a U.S. PATIENT: The isolate harbored four known beta-lactamase genes, including plasmid-mediated bla(NDM-1) and bla(CMY-6), as well as chromosomal bla(CTX-M-15) and bla(SHV-28), which accounted for resistance to all beta-lactams tested. In addition, sequence analysis identified mechanisms that could explain all other reported nonsusceptibility results, including nonsusceptibility to colistin, tigecycline, and chloramphenicol. Two plasmids, IncA/C2 and IncFIB, were closely related to mobile elements described previously and isolated from Gram-negative bacteria from China, Nepal, India, the United States, and Kenya, suggesting possible origins of the isolate and plasmids. This is one of the first K. pneumoniae isolates in the United States to have been reported to the Centers for Disease Control and Prevention (CDC) as nonsusceptible to all drugs tested, including all beta-lactams, colistin, and tigecycline.IMPORTANCE Antimicrobial resistance is a major public health threat worldwide. Bacteria that are nonsusceptible or resistant to all antimicrobials available are of major concern to patients and the public because of lack of treatment options and potential for spread. A Klebsiella pneumoniae strain that was nonsusceptible to all tested antibiotics was isolated from a U.S. PATIENT: Mechanisms that could explain all observed phenotypic antimicrobial resistance phenotypes, including resistance to colistin and beta-lactams, were identified through whole-genome sequencing. The large variety of resistance determinants identified demonstrates the usefulness of whole-genome sequencing for detecting these genes in an outbreak response. Sequencing of isolates with rare and unusual phenotypes can provide information on how these extremely resistant isolates develop, including whether resistance is acquired on mobile elements or accumulated through chromosomal mutations. Moreover, this provides further insight into not only detecting these highly resistant organisms but also preventing their spread. | 2018 | 29615503 |
| 2229 | 14 | 0.9997 | A pentaplex real-time PCR assay for rapid identification of major beta-lactamase genes KPC, NDM, CTX, CMY, and OXA-48 directly from bacteria in blood. Introduction. Antibiotic resistance, particularly in cases of sepsis, has emerged as a growing global public health concern and economic burden. Current methods of blood culture and antimicrobial susceptibility testing of agents involved in sepsis can take as long as 3-5 days. It is vital to rapidly identify which antimicrobials can be used to effectively treat sepsis cases on an individual basis. Here, we present a pentaplex, real-time PCR-based assay that can quickly identify the most common beta-lactamase genes (Klebsiella pneumoniae carbapenemase (KPC); New Delhi metallo-beta-lactamase (NDM); cefotaximase-Munich (CTX-M); cephamycin AmpC beta-lactamases (CMY); and Oxacillinase-48 (OXA-48)) from pathogens derived directly from the blood of patients presenting with bacterial septicemia.Aim. To develop an assay which can rapidly identify the most common beta-lactamase genes in Carbapenem-resistant Enterobacteriaceae bacteria (CREs) from the United States.Hypothesis/Gap Statement. Septicemia caused by carbapenem-resistant bacteria has a death rate of 40-60 %. Rapid diagnosis of antibiotic susceptibility directly from bacteria in blood by identification of beta-lactamase genes will greatly improve survival rates. In this work, we develop an assay capable of concurrently identifying the five most common beta-lactamase and carbapenemase genes.Methodology. Primers and probes were created which can identify all subtypes of Klebsiella pneumoniae carbapenemase (KPC); New Delhi metallo-beta-lactamase (NDM); cefotaximase-Munich (CTX); cephamycin AmpC beta-lactamase (CMY); and oxacillinase-48 (OXA-48). The assay was validated using 13 isolates containing various PCR targets from the Centre for Disease Control Antimicrobial Resistance Isolate Bank Enterobacterales Carbapenemase Diversity Panel. Blood obtained from volunteers was spiked with CREs and bacteria were separated, lysed, and subjected to analysis via the pentaplex assay.Results. This pentaplex assay successfully identified beta-lactamase genes derived from bacteria separated from blood at concentrations of 4-8 c.f.u. ml(-1).Conclusion. This assay will improve patient outcomes by supplying physicians with critical drug resistance information within 2 h of septicemia onset, allowing them to prescribe effective antimicrobials corresponding to the resistance gene(s) present in the pathogen. In addition, information supplied by this assay will lessen the inappropriate use of broad-spectrum antimicrobials and prevent the evolution of further antibiotic resistance. | 2021 | 34878374 |
| 2518 | 15 | 0.9997 | Plasmids Carrying Antimicrobial Resistance Genes in Gram-Negative Bacteria. Gram-negative bacteria are prevalent pathogens associated with hospital-acquired infections (HAI) that are a major challenge for patient safety, especially in intensive care units [...]. | 2022 | 36014095 |
| 5045 | 16 | 0.9997 | Emergence of colistin-resistance in extremely drug-resistant Acinetobacter baumannii containing a novel pmrCAB operon during colistin therapy of wound infections. BACKGROUND: Colistin resistance is of concern since it is increasingly needed to treat infections caused by bacteria resistant to all other antibiotics and has been associated with poorer outcomes. Longitudinal data from in vivo series are sparse. METHODS: Under a quality-improvement directive to intensify infection-control measures, extremely drug-resistant (XDR) bacteria undergo phenotypic and molecular analysis. RESULTS: Twenty-eight XDR Acinetobacter baumannii isolates were longitudinally recovered during colistin therapy. Fourteen were susceptible to colistin, and 14 were resistant to colistin. Acquisition of colistin resistance did not alter resistance to other antibiotics. Isolates had low minimum inhibitory concentrations of an investigational aminoglycoside, belonged to multi-locus sequence type 94, were indistinguishable by pulsed-field gel electrophoresis and optical mapping, and harbored a novel pmrC1A1B allele. Colistin resistance was associated with point mutations in the pmrA1 and/or pmrB genes. Additional pmrC homologs, designated eptA-1 and eptA-2, were at distant locations from the operon. Compared with colistin-susceptible isolates, colistin-resistant isolates displayed significantly enhanced expression of pmrC1A1B, eptA-1, and eptA-2; lower growth rates; and lowered fitness. Phylogenetic analysis suggested that colistin resistance emerged from a single progenitor colistin-susceptible isolate. CONCLUSIONS: We provide insights into the in vivo evolution of colistin resistance in a series of XDR A. baumannii isolates recovered during therapy of infections and emphasize the importance of antibiotic stewardship and surveillance. | 2013 | 23812239 |
| 1674 | 17 | 0.9997 | Bloodstream infections caused by multidrug-resistant gram-negative bacteria: epidemiological, clinical and microbiological features. BACKGROUND: Bloodstream infections (BSI) are associated with high morbidity and mortality. This scenario worsens with the emergence of drug-resistant pathogens, resulting in infections which are difficult to treat or even untreatable with conventional antimicrobials. The aim of this study is to describe the epidemiological aspects of BSI caused by multiresistant gram-negative bacilli (MDR-GNB). METHODS: We conducted a laboratory-based surveillance for gram-negative bacteremia over a 1-year period. The bacterial isolates were identified by MALDI-TOF/MS and the antimicrobial susceptibility testing was performed by VITEK®2. Resistance genes were identified through PCR assays. RESULTS: Of the 143 patients, 28.7% had infections caused by MDR-GNB. The risk factors for MDR bacteremia were male sex, age ≥ 60, previous antimicrobial use, liver disease and bacteremia caused by K. pneumoniae. K. pneumoniae was the most frequently observed causative agent and had the highest resistance level. Regarding the resistance determinants, SHV, TEM, OXA-1-like and CTX-M-gp1 were predominant enzymatic variants, whereas CTX-M-gp9, CTX-M-gp2, KPC, VIM, GES, OXA-48-like, NDM and OXA-23-like were considered emerging enzymes. CONCLUSIONS: Here we demonstrate that clinically relevant antibiotic resistance genes are prevalent in this setting. We hope our findings support the development of intervention measures by policy makers and healthcare professionals to face antibiotic resistance. | 2019 | 31296179 |
| 1680 | 18 | 0.9997 | Emergence of carbapenem resistant gram-negative pathogens with high rate of colistin resistance in Egypt: A cross sectional study to assess resistance trends during the COVID-19 pandemic. The current study investigated the temporal phenotypic and genotypic antimicrobial resistance (AMR) trends among multi-drug resistant and carbapenem-resistant Klebsiella pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa recovered from Egyptian clinical settings between 2020 and 2021. Bacterial identification and antimicrobial sensitivity of 111 clinical isolates against a panel of antibiotics were performed. Molecular screening for antibiotic resistance determinants along with integrons and associated gene cassettes was implemented. An alarming rate (98.2%) of these isolates were found to be phenotypically resistant to carbapenem. Although 23.9 % K. pneumoniae isolates were phenotypically resistant to colistin, no mobile colistin resistance (mcr) genes were detected. Among carbapenem-resistant isolates, bla(NDM) and bla(OXA-48)-like were the most prevalent genetic determinants and were significantly overrepresented among K. pneumoniae. Furthermore, 84.78% of K. pneumoniae isolates co-produced these two carbapenemase genes. The plasmid-mediated quinolone resistance genes (qnrS and qnrB) were detected among the bacterial species and were significantly more prevalent among K. pneumoniae. Moreover, Class 1 integron was detected in 82% of the bacterial isolates. This study alarmingly reveals elevated resistance to last-resort antibiotics such as carbapenems as well as colistin which impose a considerable burden in the health care settings in Egypt. Our future work will implement high throughput sequencing-based antimicrobial resistance surveillance analysis for characterization of novel AMR determinants. This information could be applied as a step forward to establish a robust antibiotic stewardship program in Egyptian clinical settings, thereby addressing the rising challenges of AMR. | 2024 | 38494251 |
| 1570 | 19 | 0.9996 | Genomic Insights into Two Colistin-Resistant Klebsiella pneumoniae Strains Isolated from the Stool of Preterm Neonate During the First Week of Life. Background: Klebsiella pneumoniae is a major opportunistic pathogen frequently associated with nosocomial infections, and often poses a major threat to immunocompromised patients. In our previous study, two K. pneumoniae (K36 and B13), which displayed resistance to almost all major antibiotics, including colistin, were isolated. Both isolates were not associated with infection and isolated from the stools of two preterm neonates admitted to the neonatal intensive care unit (NICU) during their first week of life. Materials and Methods: In this study, whole genome sequencing was performed on these two clinical multidrug resistant K. pneumoniae. We aimed to determine the genetic factors that underline the antibiotic-resistance phenotypes of these isolates. Results: The strains harbored bla(SHV-27), bla(SHV-71), and oqxAB genes conferring resistance to cephalosporins, carbapenems, and fluoroquinolones, respectively, but not harboring any known plasmid-borne colistin resistance determinants such as mcr-1. However, genome analysis discovered interruption of mgrB gene by insertion sequences gaining insight into the development of colistin resistance. Conclusion: The observed finding that points to a scenario of potential gut-associated resistance genes to Gram negative (K. pneumoniae) host in the NICU environment warrants attention and further investigation. | 2020 | 31545116 |