scholarly journals Comparative Analysis of Prevalence and Antibiotic Resistance in Vancomycin-Resistant Enterococcus from Clinical Samples – Demographics and Phenotypes

2021 ◽  
Vol 8 (2) ◽  
pp. 57-65
Author(s):  
Folasade Muibat Adeyemi ◽  
Nana-Aishat Yusuf ◽  
Rashidat Ronke Adeboye ◽  
Odunola Oluwaseun Oluwajide ◽  
Ajibade Kwashie Ako-Nai
Keyword(s):  
Antibiotic Resistance ◽  
Skin Lesions ◽  
Multidrug Resistant ◽  
Resistance Mechanisms ◽  
Phenotypic Characterization ◽  
Clinical Samples ◽  
Vancomycin Resistant Enterococcus ◽  
Southwest Nigeria ◽  
Vancomycin Resistant

Background: Of all enterococci species, the most renowned clinically as multidrug-resistant pathogens are Enterococcus faecium and Enterococcus faecalis. Vancomycin-resistant Enterococcus (VRE) species are the principal cause of opportunistic hospital-acquired infections, due to numerous resistance mechanisms. Methods: In this study, the prevalence and antibiotic resistance profiles of VRE according to clinical sources from three selected hospitals in Southwest-Nigeria were investigated. Altogether, 431 samples (urine, rectal, and wound swabs - caesarian section (CS), automobile accidents, and other skin lesions and abrasions) were collected from three selected hospitals in Osun State, Nigeria. Established techniques were employed for the recovery of enterococci and screening for VRE while antibiotic susceptibility tests were carried out by disc diffusion technique. Results: Altogether, 208 (48.3%) enterococci strains were recovered from which 85 (40.9%) were VRE. E. faecium predominated at 71.8% (61/85) and E. faecalis at 28.2% (24/85) as determined by phenotypic characterization. VRE isolates exhibited 100%, 97.6%, and 92.9% resistance to ampicillin, clindamycin, and quinupristin-dalfopristin (Q/D) respectively. The least resistance in-vitro was to tigecycline (27.1%). None of the antibiotics exhibited 100% activity against all the isolates. vanA resistant phenotype was prevalent at 65.9%. E. faecium from all study locations displayed higher levels of resistance than E. faecalis. Multiple antibiotic resistance (MAR) indices in all VRE isolates were ≥0.2, all being multidrug-resistant. Conclusions: The high prevalence rate along with the high level of multidrug resistance observed in the present study is worrisome and poses a continuous threat in the therapy of illnesses triggered by VRE as vancomycin was perceived as a drug of choice to curb enterococcal infections.

scholarly journals 1280. In-Vitro Activity of Cefiderocol, Imipenem/Relebactam, & Ceftazidime/Avibactam in Ceftolozane/Tazobactam Resistant Strains of Multidrug Resistant Pseudomonas aeruginosa

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S655-S655
Author(s):  
Daniel Navas ◽  
Angela Charles ◽  
Amy Carr ◽  
Jose Alexander
Keyword(s):  
Multidrug Resistant ◽  
Resistance Mechanisms ◽  
Vitro Activity ◽  
Clinical Isolates ◽  
Resistance Testing ◽  
Clinical Samples ◽  
In Vitro Activity ◽  
Carbapenemase Gene ◽  
Resistant Strains

Abstract Background The activity of imipenem/relebactam (I/R), ceftazidime/avibactam (CZA) and cefiderocol (FDC) were evaluated against clinical isolates of multidrug resistant (MDR) strains of P. aeruginosa which was resistant to ceftolozane/tazobactam (C/T). The recent increase of MDR P. aeruginosa strains isolated from clinical samples has prompted research and development of new antimicrobials that can withstand its multiple resistance mechanisms. C/T is an effective option for treatment of MDR P. aeruginosa in our facility with only 10% of resistance in MDR strains, but the emergence of resistance may occur due to the presence of a carbapenemase gene or an ampC mutation. Methods Antimicrobial susceptibility testing for C/T Etest® (bioMérieux, Inc.) were performed on all MDR strains initially screened by the VITEK2® (bioMérieux, Inc.). 10% (n=20) of all MDR isolates were resistant to C/T by the CLSI 2019 breakpoints. These resistant isolates were tested for presence of a carbapenemase gene using the GeneXpert CARBA-R (Cepheid®) PCR and against CZA Etest® (bioMérieux, Inc.) I/R gradient strips (Liofilchem®) and FDC broth microdilution (Thermo Scientific™ Sensititre™). Results A total of 20 clinical isolates of MDR P. aeruginosa resistant to C/T were tested following standardized CLSI protocols and techniques. All 20 isolates were screened for the presence of a carbapenemase gene (blaVIM, blaNDM, blaKPC, blaOXA-48, blaIMP). A blaVIM gene was detected in 6 (30%) out of 20 isolates. FDC demonstrated the greatest activity with 85% (n=17) of susceptible isolates (CLSI MIC <4µg/dL). CZA (CLSI MIC <8µg/dL) and I/R (FDA MIC <2µg/dL) showed 15% (n=3) and 10% (n=2) of susceptible isolates respectively. FDC was active against all 6 blaVIM isolates, where all 6 strains were resistant to CZA and I/R as expected. 3 isolates tested non-susceptible against FDC; additional characterization was not performed at this time. Conclusion Based on these results, FDC demonstrated the greatest in-vitro activity against C/T resistant strains of MDR P. aeruginosa. FDC also demonstrated activity against all 6 MDR P. aeruginosa carrying blaVIM gene. FDC is a strong option to consider on MDR P. aeruginosa strains based on a resistance testing algorithm and a cost/effective protocol. Disclosures All Authors: No reported disclosures

scholarly journals Is there any association between antibiotic resistance and virulence genes in Enterococcus isolates?

2019 ◽  
Vol 6 (12) ◽  
pp. 310-315
Author(s):  
Nergis Aşgın ◽  
Emre Taşkın
Keyword(s):  
Antibiotic Resistance ◽  
Virulence Genes ◽  
Multidrug Resistant ◽  
Automated System ◽  
High Frequencies ◽  
Resistant Strains ◽  
Vancomycin Resistant ◽  
High Level

Objective: In this study, we aim to determine the frequency of antibiotic resistance and five virulence genes in Enterococcus species and the relationship between antibiotic resistance and virulence genes. Material and Methods: A total of 86 Enterococcus strains isolated from inpatients between 2015 and 2016 were included. Identification and antibiotic susceptibilities of strains were determined using a BD Phoenix fully automated system. The presence of virulence-associated genes (esp, gel E, asa1, hyl, and cyl) were investigated by using PCR method. Results: Of the 86 Enterococcus strains, 53 (61.6%) and 33 (38.4%) were Enterococcus faecium and Enterococcus faecalis, respectively. Vancomycin and high-level gentamicin resistance (HLGR) in E. faecalis strains were 0.6% and 60.6%, respectively. Furthermore, 52 of the 53 E. faecium strains were both vancomycin-resistant and HLGR. The frequency of esp, gel E, asa1, cyl, and hyl was 91.9%, 60.5%, 54.7%, 43%, and 26.7%, respectively.  The asa 1, cyl, and gel E genes were detected at high frequencies in vancomycin-susceptible and non-HLGR strains, whereas hyl gene was detected at high frequencies in vancomycin-resistant and HLGR strains. Conclusion: Virulence genes were more frequent in vancomycin-susceptible and non-HLGR Enterococcus strains than in the resistant strains. Although infections caused by multidrug-resistant strains are difficult to treat, it should be considered that susceptible strains have more virulence genes. This may reduce the in vivo efficacy of drugs and lead to treatment failures. Therefore, in addition to the in vitro susceptibilities of drugs, clinical efficacy should be monitored.

scholarly journals Low Occurrence of Virulence Determinants in Vancomycin-Resistant Enterococcus from Clinical Samples in Southwest Nigeria

2021 ◽  
Vol In Press (In Press) ◽  
Author(s):  
Folasade Muibat Adeyemi ◽  
Nana-Aishat Yusuf ◽  
Rashidat Ronke Adeboye ◽  
Omotayo Opemipo Oyedara
Keyword(s):  
Virulence Factors ◽  
Molecular Identification ◽  
Resistance Genes ◽  
Clinical Samples ◽  
Screening Methods ◽  
Vancomycin Resistant Enterococcus ◽  
Virulence Determinants ◽  
Southwest Nigeria ◽  
Vancomycin Resistant ◽  
Polymerase Chain

Background: The virulence factors of enterococci play a major role in the pathogenicity of enterococcal strains. Objectives: This study aimed to evaluate virulence factors and detect selected virulence and resistance genes in vancomycin-resistant Enterococcus (VRE) from clinical samples from southwest Nigeria. Methods: The VRE isolates (n = 85) recovered from clinical samples were characterized using conventional microbiology techniques, and molecular identification was made with ddlE primers. Phenotypic screening for five virulence determinants and detection of virulence and resistance genes using a polymerase chain reaction were carried out. Results: Phenotypic identification revealed 61 Enterococcus faecium and 24 Enterococcus faecalis. All the isolates hydrolyzed bile. Moreover, 88.2% of the isolates produced biofilm; however, 72.9% of the isolates produced gelatinase enzyme. Altogether, six isolates (7%) produced all five virulence factors. The least virulence factor expressed by the two species E. faecium and E. faecalis was DNase at 21.3% and 29.2% followed by cytolysin at 27.9% and 41.7%, respectively. Only 25 isolates (29.4%), including 23 E. faecium (37.7%) and only 2 (8.3%) E. faecalis isolates, revealed bands with molecular identification. Additionally, VRE isolates showed bands for asa1 (16%); only 1 (4%) isolate had the hyl gene and vanB gene, respectively. Conclusions: The absence of vanA and low detection of vanB resistance genes suggest the possible presence of other van types and emphasizes the need for further investigations on the incidence of other van genes using molecular screening methods in enterococci isolates in Nigeria for surveillance purposes. Moreover, the low occurrence of virulence genes implies that there might be other mediators of pathogenicity involved in Enterococcus virulence traits.

scholarly journals 1221. Genomic Factors Affecting the Efficacy of Antimicrobial Therapy in Daptomycin-, Linezolid-, Vancomycin-Resistant Enterococcus faecium (DLVRE)

2021 ◽  
Vol 8 (Supplement_1) ◽  
pp. S700-S701
Author(s):  
Samuel W Gatesy ◽  
Nathan B Pincus ◽  
William Justin Moore ◽  
Omar Al-Heeti ◽  
Tejas Joshi ◽  
...  
Keyword(s):  
Antimicrobial Resistance ◽  
Real Time ◽  
Antimicrobial Therapy ◽  
Resistance Mechanisms ◽  
Clinical Microbiology Laboratory ◽  
Vancomycin Resistant Enterococcus ◽  
Single Chromosome ◽  
Vancomycin Resistant ◽  
Synergy Testing

Abstract Background Nosocomial acquisition of vancomycin-resistant Enterococcus (VRE) is one of the most challenging problems in healthcare. As Enterococcus isolates are increasingly resistant to vancomycin, clinicians now rely on alternative antimicrobial therapies including linezolid and daptomycin (DAP) to treat infections. For multidrug-resistant (MDR) VRE, combination therapy with beta-lactams and daptomycin has been shown to be effective. Methods Following initiation of empiric DAP and ceftaroline (CPT) for an MDR E. faecium bloodstream infection (VRE_001), we aimed to determine if there existed in vitro synergy between both agents that supported their clinical use. Combination synergy testing was performed using E-test strips and minimal inhibitory concentrations (MICs) were read at 24 hours. For whole genome sequence-based analysis (WGS), genomic DNA from VRE_001 was used for both short read (Illumina MiSeq) and long-read sequencing (MinION, Nanopore). The complete genome was assembled and the NCBI AMRFinderPlus program used to identify known resistance mechanisms. Results Original MICs of VRE_001 from the clinical microbiology laboratory at Northwestern Memorial revealed an MDR E. faecium (Table 1). Combination synergy testing in the experimental laboratory revealed only modest amounts of synergy between CPT and DAP (Table 2). Following WGS, VRE_001 was identified as an ST-584 E. faecium with a 3.2 Mbp genome, including a single chromosome and five plasmids. WGS analysis revealed several mechanisms of antimicrobial resistance (Table 3) genetically supporting the observed MDR-DLVRE phenotype. Conclusion Our investigational antimicrobial testing allowed for real-time in vitro analysis of synergistic MICs in a case of DLVRE bacteremia. Despite the fact that in vitro testing of CPT and DAP did not support the clinical usage of combination antimicrobial therapy, the patient cleared their blood cultures. WGS of VRE_001 revealed a plethora of antimicrobial resistance mechanisms including three mutations that explain high levels of DAP resistance. Synergy testing is not routinely available in most clinical laboratories, but rapid implementation of investigational MIC testing paired with genomic analysis may one day successfully support real-time clinical decision making. Disclosures All Authors: No reported disclosures

scholarly journals Clinically Relevant Gram-Negative Resistance Mechanisms Have No Effect on the Efficacy of MC-1, a Novel Siderophore-Conjugated Monocarbam

2012 ◽  
Vol 56 (12) ◽  
pp. 6334-6342 ◽  
Author(s):  
Craig J. McPherson ◽  
Lisa M. Aschenbrenner ◽  
Brian M. Lacey ◽  
Kelly C. Fahnoe ◽  
Margaret M. Lemmon ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Outer Membrane ◽  
Negative Resistance ◽  
Multidrug Resistant ◽  
Resistance Mechanisms ◽  
Gram Negative ◽  
Content Type ◽  
Pharmacologically Active

ABSTRACTThe incidence of hospital-acquired infections with multidrug-resistant (MDR) Gram-negative pathogens is increasing at an alarming rate. Equally alarming is the overall lack of efficacious therapeutic options for clinicians, which is due primarily to the acquisition and development of various antibiotic resistance mechanisms that render these drugs ineffective. Among these mechanisms is the reduced permeability of the outer membrane, which prevents many marketed antibiotics from traversing this barrier. To circumvent this, recent drug discovery efforts have focused on conjugating a siderophore moiety to a pharmacologically active compound that has been designed to hijack the bacterial siderophore transport system and trick cells into importing the active drug by recognizing it as a nutritionally beneficial compound. MC-1, a novel siderophore-conjugated β-lactam that promotes its own uptake into bacteria, has exquisite activity against many Gram-negative pathogens. While the inclusion of the siderophore was originally designed to facilitate outer membrane penetration into Gram-negative cells, here we show that this structural moiety also renders other clinically relevant antibiotic resistance mechanisms unable to affect MC-1 efficacy. Resistance frequency determinations and subsequent characterization of first-step resistant mutants identified PiuA, a TonB-dependent outer membrane siderophore receptor, as the primary means of MC-1 entry intoPseudomonas aeruginosa. While the MICs of these mutants were increased 32-fold relative to the parental strainin vitro, we show that this resistance phenotype is not relevantin vivo, as alternative siderophore-mediated uptake mechanisms compensated for the loss of PiuA under iron-limiting conditions.

scholarly journals Production of a New Thiopeptide Antibiotic, TP-1161, by a Marine Nocardiopsis Species

2010 ◽  
Vol 76 (15) ◽  
pp. 4969-4976 ◽  
Author(s):  
Kerstin Engelhardt ◽  
Kristin F. Degnes ◽  
Michael Kemmler ◽  
Harald Bredholt ◽  
Espen Fj�rvik ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Molecular Taxonomy ◽  
Multidrug Resistant ◽  
Peptide Antibiotic ◽  
Indicator Organisms ◽  
Bacterial Strains ◽  
Pcr Screening ◽  
Vancomycin Resistant ◽  
Antibacterial And Antifungal

ABSTRACT Twenty-seven marine sediment- and sponge-derived actinomycetes with a preference for or dependence on seawater for growth were classified at the genus level using molecular taxonomy. Their potential to produce bioactive secondary metabolites was analyzed by PCR screening for genes involved in polyketide and nonribosomal peptide antibiotic synthesis. Using microwell cultures, conditions for the production of antibacterial and antifungal compounds were identified for 15 of the 27 isolates subjected to this screening. Nine of the 15 active extracts were also active against multiresistant Gram-positive bacterial and/or fungal indicator organisms, including vancomycin-resistant Enterococcus faecium and multidrug-resistant Candida albicans. Activity-guided fractionation of fermentation extracts of isolate TFS65-07, showing strong antibacterial activity and classified as a Nocardiopsis species, allowed the identification and purification of the active compound. Structure elucidation revealed this compound to be a new thiopeptide antibiotic with a rare aminoacetone moiety. The in vitro antibacterial activity of this thiopeptide, designated TP-1161, against a panel of bacterial strains was determined.

scholarly journals Persistent Bacteremia fromPseudomonas aeruginosawithIn VitroResistance to the Novel Antibiotics Ceftolozane-Tazobactam and Ceftazidime-Avibactam

2016 ◽  
Vol 2016 ◽  
pp. 1-5 ◽  
Author(s):  
Louie Mar Gangcuangco ◽  
Patricia Clark ◽  
Cynthia Stewart ◽  
Goran Miljkovic ◽  
Zane K. Saul
Keyword(s):  
Susceptibility Testing ◽  
Resistance Mechanism ◽  
Multidrug Resistant ◽  
Resistance Mechanisms ◽  
Blood Cultures ◽  
The Novel ◽  
First Case ◽  
Persistent Bacteremia ◽  
Novel Antibiotics

Ceftazidime-avibactam and ceftolozane-tazobactam are new antimicrobials with activity against multidrug-resistantPseudomonas aeruginosa. We present the first case of persistentP.aeruginosabacteremia within vitroresistance to these novel antimicrobials. A 68-year-old man with newly diagnosed follicular lymphoma was admitted to the medical intensive care unit for sepsis and right lower extremity cellulitis. The patient was placed empirically on vancomycin and piperacillin-tazobactam. Blood cultures from Day 1 of hospitalization grewP.aeruginosasusceptible to piperacillin-tazobactam and cefepime identified using VITEK 2 (Biomerieux, Lenexa, KS). Repeat blood cultures from Day 5 grewP.aeruginosaresistant to all cephalosporins, as well as to meropenem by Day 10. Susceptibility testing performed by measuring minimum inhibitory concentration byE-test (Biomerieux, Lenexa, KS) revealed that blood cultures from Day 10 were resistant to ceftazidime-avibactam and ceftolozane-tazobactam. The Verigene Blood Culture-Gram-Negative (BC-GN) microarray-based assay (Nanosphere, Inc., Northbrook, IL) was used to investigate underlying resistance mechanism in theP.aeruginosaisolate but CTX-M, KPC, NDM, VIM, IMP, and OXA gene were not detected. This case report highlights the well-documented phenomenon of antimicrobial resistance development inP.aeruginosaeven during the course of appropriate antibiotic therapy. In the era of increasing multidrug-resistant organisms, routine susceptibility testing ofP. aeruginosato ceftazidime-avibactam and ceftolozane-tazobactam is warranted. Emerging resistance mechanisms to these novel antibiotics need to be further investigated.

Sign in / Sign up

Export Citation Format

Share Document