scholarly journals Evaluation of Genotypic and Phenotypic Methods to Detect Carbapenemase Production in Gram-Negative Bacilli

2017 ◽  
Vol 63 (3) ◽  
pp. 723-730 ◽  
Author(s):  
Allison R McMullen ◽  
Melanie L Yarbrough ◽  
Meghan A Wallace ◽  
Angela Shupe ◽  
Carey-Ann D Burnham
Keyword(s):  
Carbapenem Resistance ◽  
Accurate Method ◽  
Genetic Determinants ◽  
Accurate Identification ◽  
Gram Negative ◽  
Healthcare Facilities ◽  
Carbapenem Resistant ◽  
Phenotypic Screen ◽  
Acinetobacter Baumannii Complex ◽  
Phenotypic Methods

Abstract BACKGROUND Carbapenemase-producing gram-negative bacteria (CP-GNB) are an urgent and expanding public health threat. Rapid and accurate identification of these organisms facilitates infection prevention efforts in healthcare facilities. The objective of our study was to evaluate methods to detect and identify CP-GNB. METHODS We examined 189 carbapenem-resistant GNB(CR-GNB), including Enterobacteriaceae, Pseudomonas aeruginosa, and Acinetobacter baumannii complex, using 3 different methods: 2 methods to screen isolates of GNB for carbapenemase production [the carbapenem inactivation method (CIM) and 2 chromogenic agars] and a molecular method (Cepheid GeneXpert Carba-R) to identify the mechanism of carbapenem resistance and the associated resistance genes (blaKPC, blaNDM, blaIMP, blaOXA-48-like, and blaVIM). RESULTS The CIM was a simple and inexpensive phenotypic screen to differentiate between CR-GNB and CP-GNB, with improved analytical performance characteristics and inter-reader correlation compared to the modified Hodge test. Both chromogenic agars evaluated (HardyCHROM CRE and chromID CARBA) were able to support growth of most of the organisms tested, including isolates possessing the blaOXA-48-like gene. However, these media had a low analytical specificity for carbapenemase production, with breakthrough of CR-GNB that did not produce a carbapenemase. The Xpert Carba-R assay was rapid and easy to perform, and demonstrated 100% positive and negative agreement for characterization of genetic determinants of carbapenem resistance. CONCLUSIONS Screening by CIM followed by the Xpert Carba-R PCR is an accurate method for detecting and characterizing CP-GNB, including Enterobacteriaceae, P. aeruginosa, and A. baumannii complex.

scholarly journals Performance of the BD Phoenix CPO detect assay for detection and classification of carbapenemase-producing organisms

2020 ◽  
Author(s):  
Laura Berneking ◽  
Anna Both ◽  
Benjamin Berinson ◽  
Armin Hoffmann ◽  
Marc Lütgehetmann ◽  
...  
Keyword(s):  
Susceptibility Testing ◽  
Carbapenem Resistance ◽  
Alternative Methods ◽  
Gram Negative Bacteria ◽  
Accurate Identification ◽  
Gram Negative ◽  
Carbapenem Resistant ◽  
Gradient Diffusion ◽  
Assay Performance

AbstractIncreasing worldwide, prevalence of carbapenem-resistant gram-negative bacteria demands urgent a need for rapid detection and accurate identification of carbapenemases. The BD Phoenix CPO detect (PCD) assay possesses an in-built capacity for parallel susceptibility testing and detection of carbapenemases. Here, the ability of the assay to detect and classify carbapenemase production was tested in a collection of carbapenem-resistant Enterobacterales and non-fermentative gram-negative rods. The ability of the PCD assay to detect and classify carbapenemases was investigated in a collection of 194 clinical, carbapenem-resistant isolates (Enterobacterales [n = 65]; non-fermentative gram-negative rods [n = 129]). AST results were compared to MICS determined by gradient diffusion to determine accuracy of the PCD assay. The accuracy of the PCD assay to detect carbapenemases was compared to the results of molecular isolate characterization using a LDT multiplex carbapenemase PCR assay. All 194 isolates classified as carbapenem-resistant by reference susceptibility testing were also classified correctly as CRO by the PCD assay. Performance analysis of the PCD assay to detect carbapenemase production revealed an overall sensitivity of 98.29% and specificity of 17.95% for the detection of carbapenemase production. For the classification of carbapenemases classes A, B, and D, the PCD correctly classified 79.17% Enterobacterales and 67.16% non-fermentative gram-negative rods. The PCD assay is a reliable tool for the detection of carbapenem resistance and allows for parallel analysis of carbapenemase production. However, while sensitivity is high, low specificity in carbapenemase detection and erroneous classification demands mandatory confirmation by alternative methods, especially in non-fermentative gram-negative bacteria.

scholarly journals An overview of carbapenem, its resistance and therapeutic options for infections caused by carbapenem resistant bacteria

2020 ◽  
Vol 9 (9) ◽  
pp. 1454
Author(s):  
Hari P. Nepal ◽  
Rama Paudel
Keyword(s):  
Bacterial Infections ◽  
Carbapenem Resistance ◽  
Therapeutic Options ◽  
Resistant Bacteria ◽  
Gram Negative Bacteria ◽  
Beta Lactam ◽  
Gram Negative ◽  
Penicillin Binding Proteins ◽  
Carbapenem Resistant ◽  
The World

Carbapenems are beta-lactam drugs that have broadest spectrum of activity. They are commonly used as the drugs of last resort to treat complicated bacterial infections. They bind to penicillin binding proteins (PBPs) and inhibit cell wall synthesis in bacteria. Important members that are in clinical use include doripenem, ertapenem, imipenem, and meropenem. Unlike other members, imipenem is hydrolyzed significantly by renal dehydropeptidase; therefore, it is administered together with an inhibitor of renal dehydropeptidase, cilastatin. Carbapenems are usually administered intravenously due to their low oral bioavailability. Most common side effects of these drugs include nausea, vomiting, diarrhea, skin rashes, and reactions at the infusion sites. Increasing resistance to these antibiotics is being reported throughout the world and is posing a threat to public health.  Primary mechanisms of carbapenem resistance include expulsion of drug and inactivation of the drug by production of carbapenemases which may not only hydrolyze carbapenem, but also cephalosporin, penicillin, and aztreonam. Resistance especially among Gram negative bacteria is of much concern since there are only limited therapeutic options available for infections caused by carbapenem resistant Gram-negative bacterial pathogens. Commonly used drugs to treat such infections include polymyxins, fosfomycin and tigecycline.

scholarly journals Near-infrared Spectroscopy evaluations for rapid differentiation of carbapenem resistant Enterobacteriaceae from susceptible strains

2020 ◽  
Author(s):  
Bushra Alharbi ◽  
Maggy T. Sikulu-Lord ◽  
Anton Lord ◽  
Hosam M Zowawi ◽  
Ella Trembizki
Keyword(s):  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Predictive Accuracy ◽  
Bacterial Species ◽  
Carbapenem Resistance ◽  
Accurate Identification ◽  
Carbapenem Resistant ◽  
Global Threat ◽  
Carbapenem Resistant Enterobacteriaceae

AbstractAntimicrobial resistance (AMR) caused by Carbapenem-Resistant Enterobacteriaceae (CRE) is a global threat. Accurate identification of these bacterial species with associated AMR is critical for their management. While highly accurate methods to detect CRE are available, they are costly, timely and require expert skills making their application infeasible in low-resource settings. Here, we investigated the potential of Near-infrared Spectroscopy (NIRS) for a range of applications; i) the detection and differentiation of isolates of two pathogenic Enterobacteriaceae species, Klebsiella pneumoniae and Escherichia coli and, ii) the differentiation of carbapenem resistant and susceptible K. pneumoniae. NIRS has successfully differentiated between K. pneumoniae and E. coli isolates with a predictive accuracy of 89.04% (95% CI; 88.7-89.4%). K. pneumoniae isolates harbouring carbapenem resistance determinants were differentiated from susceptible K. pneumoniae strains with an accuracy of 85% (95% CI; 84.2-86.1%). To our knowledge, this is the largest demonstration of a proof of concept for the utility and feasibility of NIRS for rapidly differentiating between K. pneumoniae from E.coli as well as from carbapenem resistant K. pneumoniae from susceptible strains.

scholarly journals Genome-Wide Identification of Carbapenem-Resistant Gram- Negative Bacterial (CR-GNB) Isolates Retrieved From Hospitalized Patients in Bihar, India

2021 ◽  
Author(s):  
Namrata Kumari ◽  
Mukesh Kumar ◽  
Amit Katiyar ◽  
Abhay Kumar ◽  
Pallavi Priya ◽  
...  
Keyword(s):  
Resistance Genes ◽  
Carbapenem Resistance ◽  
Cross Sectional Study ◽  
Clinical Isolates ◽  
Cross Sectional ◽  
Gram Negative ◽  
Carbapenem Resistant ◽  
Genome Wide ◽  
Synergy Test ◽  
Global Threat

Abstract Carbapenemase-producing clinical isolates are becoming more common over the world, posing a severe public health danger, particularly in developing nations like India. Carbapenem-resistant Gram-negative bacterial (CR-GNB) infection has become a fast-expending global threat with limited antibiotic choice and significant mortality. The aim of this study was to highlight the carbapenem-resistance among clinical isolates of hospital admitted patients in Bihar, India. A cross-sectional study was conducted with 101 clinical isolates of E. coli, K. pneumoniae, A. baumannii, and P. aeruginosa. All GNB isolates were tested for their antimicrobial susceptibility using double disc synergy test / modified hodge test (DDST/MHT) and subsequently confirmed carbapenemase-producing isolates were evaluated for carbapenem-resistance genes using whole-genome sequencing (genotypically) method. The overall percentage of carbapenem-resistance among GNB was (17/101) 16.83%. The AMR analysis demonstrates a significantly high prevalence of blaCTX−M followed by blaSHV, blaTEM, blaOXA and blaNDM β-lactams carbapenem-resistance genes among clinical isolates of GNB. Co-occurrence of carbapenemase-encoding genes with blaNDM was found in 70.6% of carbapenemase-producing isolates. Our study highlights the mechanism of carbapenem-resistance to curb the overwhelming threat posed by emergence of drug-resistance in India.

scholarly journals Using Molecular Diagnostics to Develop Therapeutic Strategies for Carbapenem-Resistant Gram-Negative Infections

2021 ◽  
Vol 11 ◽  
Author(s):  
Fred C. Tenover
Keyword(s):  
Carbapenem Resistance ◽  
Multidrug Resistant ◽  
Therapeutic Strategies ◽  
Beta Lactam ◽  
Gram Negative ◽  
Molecular Tests ◽  
Negative Results ◽  
Carbapenem Resistant ◽  
Class B ◽  
Global Threat

Infections caused by multidrug-resistant Gram-negative organisms have become a global threat. Such infections can be very difficult to treat, especially when they are caused by carbapenemase-producing organisms (CPO). Since infections caused by CPO tend to have worse outcomes than non-CPO infections, it is important to identify the type of carbapenemase present in the isolate or at least the Ambler Class (i.e., A, B, or D), to optimize therapy. Many of the newer beta-lactam/beta-lactamase inhibitor combinations are not active against organisms carrying Class B metallo-enzymes, so differentiating organisms with Class A or D carbapenemases from those with Class B enzymes rapidly is critical. Using molecular tests to detect and differentiate carbapenem-resistance genes (CRG) in bacterial isolates provides fast and actionable results, but utilization of these tests globally appears to be low. Detecting CRG directly in positive blood culture bottles or in syndromic panels coupled with bacterial identification are helpful when results are positive, however, even negative results can provide guidance for anti-infective therapy for key organism-drug combinations when linked to local epidemiology. This perspective will focus on the reluctance of laboratories to use molecular tests as aids to developing therapeutic strategies for infections caused by carbapenem-resistant organisms and how to overcome that reluctance.

Determination of carbapenemase genes in clinical isolates using Cepheid Xpert Carba-R

2021 ◽  
pp. 16-19
Author(s):  
N. I. Gabrielyan ◽  
V. G. Kormilitsyna ◽  
V. K. Zaletaeva ◽  
A. V. Krotevich ◽  
I. A. Miloserdov ◽  
...  
Keyword(s):  
Targeted Therapy ◽  
Infection Control ◽  
Resistance Genes ◽  
Carbapenem Resistance ◽  
Critical Issue ◽  
Sensitivity Study ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Carbapenem Resistant

Detection of carbapenem resistance genes is a critical issue for hospitals due to possible recommendations for infection control and targeted therapy. The Cepheid Xpert instrument, a Carba-R test for the detection and differentiation of five common carbapenemase genes, was tested from September 2020 to February 2021. As part of the approbation, 20 tests were provided. This review presents the results of the approbation of a relatively regular sensitivity study on Siemens WalkAway‑96 plus. Cepheid Xpert Carba-R analysis has been shown to be an accurate and fast tool for detecting colonization by carbapenem-resistant gram-negative bacteria, which can help limit the spread of these organisms in hospitals.

scholarly journals Near-Infrared Spectroscopy Evaluations for the Differentiation of Carbapenem-Resistant from Susceptible Enterobacteriaceae Strains

Diagnostics ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 736
Author(s):  
Bushra Alharbi ◽  
Maggy Sikulu-Lord ◽  
Anton Lord ◽  
Hosam M. Zowawi ◽  
Ella Trembizki
Keyword(s):  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Predictive Accuracy ◽  
Bacterial Species ◽  
Carbapenem Resistance ◽  
Accurate Identification ◽  
E Coli ◽  
Carbapenem Resistant ◽  
Global Threat

Antimicrobial Resistance (AMR) caused by Carbapenem-Resistant Enterobacteriaceae (CRE) is a global threat. Accurate identification of these bacterial species with associated AMR is critical for their management. While highly accurate methods to detect CRE are available, they are costly, timely and require expert skills, making their application infeasible in low-resource settings. Here, we investigated the potential of Near-Infrared Spectroscopy (NIRS) for a range of applications: (i) the detection and differentiation of isolates of two pathogenic Enterobacteriaceae species, Klebsiella pneumoniae and Escherichia coli, and (ii) the differentiation of carbapenem resistant and susceptible K. pneumoniae. NIRS has successfully differentiated between K. pneumoniae and E. coli isolates with a predictive accuracy of 89.04% (95% CI; 88.7–89.4%). K. pneumoniae isolates harbouring carbapenem-resistance determinants were differentiated from susceptible K. pneumoniae strains with an accuracy of 85% (95% CI; 84.2–86.1%). To our knowledge, this is the largest proof of concept demonstration for the utility and feasibility of NIRS to rapidly differentiate between K. pneumoniae and E. coli as well as carbapenem-resistant K. pneumoniae from susceptible strains.

scholarly journals Detection and Characterization of Carbapenem resistant Gram-negative bacilli isolates recovered from hospitalized patients at Soba University Hospital, Sudan

2020 ◽  
Author(s):  
Hana S. Elbadawi ◽  
Kamal M. Elhag ◽  
Elsheikh Mahgoub ◽  
Hisham N Altayb ◽  
Francine Ntoumi ◽  
...  
Keyword(s):  
Resistance Genes ◽  
Nosocomial Infections ◽  
Carbapenem Resistance ◽  
Clinical Isolates ◽  
University Hospital ◽  
P Value ◽  
Relative Distribution ◽  
Gram Negative ◽  
Carbapenem Resistant ◽  
Carbapenemase Gene

Abstract Background:Antimicrobial resistance (AMR) poses a threat to global health security. Whilst over the past decade, there has been an increase in reports of nosocomial infections globally caused by carbapenem resistant Gram-negative bacilli (GNB), data from Africa have been scanty. We performed a study of carbapenem resistance genes among GNB isolated from patients treated in hospitals in Khartoum state, Sudan.Methods:A cross-sectional study was conducted at Soba University Hospital (SUH) and Institute of Endemic Diseases, University of Khartoum for the period October 2016 to February 2017. A total of 206 GNB isolates from different clinical specimens were analyzed for carbapenem resistance genes using phenotypic tests and affirmed by genes detection. Multiplex PCR was performed for each strain to detect the carbapenemase genes, including the blaNDM, blaVIM, blaIMP, blaKPC, and blaOXA-48. In addition to blaCTXM, blaTEM and blaSHV. DNA sequencing and bioinformatics analysis were used to detect genes subtypes.Findings:Of 206 isolates, 171 (83%) were confirmed resistant phenotypically and 121 (58.7%) isolates were positive for the presence of one or more carbapenemase gene. New Delhi metallo-β-lactamase (NDM) types were the most predominant genes, blaNDM 107(88.4%). Others included blaIMP 7 (5.7%), blaOXA-48 5(4.1%), blaVIM 2 (1.6%) and blaKPC 0 (0%). Co- resistance genes with NDM producing GNB were detected in 87 (81.3%) of all blaNDM positive isolates. A significant association between phenotypic and genotypic resistance was observed (P- value < 0.001). NDM-1 was the most sub type was observed in 75 isolates (70 %), other subtypes were NDM- 5 and NDM-6. Infections due to Carbapenem resistant GNB are increasing at SUH, with the blaNDM being the prevalent genes among clinical isolates and belong to the Indian lineage.Conclusions:The frequency of carbapenemase producing bacilli was found to be improperly high in Khartoum hospitals. NDM was found to be the most prevalent carbapenemase gene among clinical isolates. Close surveillance across all hospitals in Sudan is required. The relative distribution of Carbapenemase genes among GNB in nosocomial infections in Africa needs to be defined.

scholarly journals Emerging resistance to carbapenem among Gram-negative bacteria in a tertiary care hospital

2020 ◽  
Vol 11 (SPL2) ◽  
pp. 153-156
Author(s):  
Pooja Nair ◽  
Renu Mathews ◽  
Kalyani M
Keyword(s):  
Minimum Inhibitory Concentration ◽  
Inhibitory Concentration ◽  
Tertiary Care Hospital ◽  
Tertiary Care ◽  
Carbapenem Resistance ◽  
Clinical Samples ◽  
Care Hospital ◽  
Gram Negative ◽  
Carbapenem Resistant ◽  
Diffusion Technique

The emergence of bacterial antibiotic resistance is a cardinal concern in the health care system. The spread of resistance in Enterobacteriaceae and non-fermenters to the currently available drugs make the treatment of serious nosocomial infections troublesome.  The purpose of the study is to find out the carbapenem resistance among Gram-negative bacilli in a tertiary care hospital. Antibiotic susceptibility pattern of 1913 aerobic Gram-negative bacilli isolated from clinical samples was made for a period of 6 months. All the isolates were tested for susceptibility to antibiotics by the Kirby-Bauer disc diffusion technique according to CLSI guidelines. Carbapenemase production was confirmed by the Modified Hodge Test (MHT). Minimum Inhibitory Concentration (MIC) by Epsilometer (E) test was performed (for Imipenem and Meropenem) for carbapenem-resistant strains. A total of 1731 clinical samples, 1913 Gram-negative bacilli were isolated. 1476 (77.1%) were Enterobacteriaceae and 433 (22.6%) were non-fermenters. 54 were carbapenemase-producing Gram-negative bacilli. Meropenem E test was done for carbapenemase-producing Gram-negative bacilli. The minimum inhibitory concentration for Meropenem ranged from 0.002μg/ml to 32μg/ml. To overcome the problem of emerging resistance, combined interaction and cooperation of microbiologists, clinicians and the infection control team is needed.

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