Phenotypic and genotypic detection of carbapenemase production among gram negative bacteria isolated from hospital acquired infections

Vamsi, Sreeja K.; Moorthy, Rama S.; Hemiliamma, Mary N.; Reddy, Rama B. Chandra; chanderakant, Deepak J.; Sirikonda, Shravani

doi:10.15537/smj.2022.43.3.20210809

Cited by 16 publications

(15 citation statements)

References 24 publications

(36 reference statements)

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“…More than one carbapenemase gene was detected among 79/80 Klebsiella isolates and in all E. coli isolates. These findings were similarly stated by other researchers [ 18 , 20 , 30 , 31 , 34 – 36 ]. Hereby, the high prevalence of more than one carbapenemase gene in Enterobacterales isolates may illustrate the hastily propagating resistance.…”

Section: Discussionsupporting

confidence: 91%

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Ceftazidime-Avibactam plus aztreonam synergistic combination tested against carbapenem-resistant Enterobacterales characterized phenotypically and genotypically: a glimmer of hope

Taha

Kader²,

Shawky³

et al. 2023

Ann Clin Microbiol Antimicrob

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Background Carbapenemase-producing Enterobacterales (CPE) show rapid global dissemination and pose a significant therapeutic challenge. This study aimed to characterize carbapenemase-producing Klebsiella spp. and Escherichia coli (E. coli) phenotypically and genotypically and evaluate the effect of ceftazidime/ avibactam plus aztreonam combination. Methods A total of 219 Klebsiella species and 390 E. coli strains were isolated from clinical samples, in which 80 Klebsiella spp. and 20 E coli isolates were resistant to tested carbapenems (imipenem, ertapenem, meropenem) by disk diffusion/broth dilution method and Vitek-2 compact system. MASTDISCS Combi Carba plus discs and real time PCR were used to determine type of carbapenemase phenotypically and genotypically, respectively. Interestingly, the synergistic effect between ceftazidime-avibactam (E-test) and aztreonam (disc) was tested against the CPE isolates. Results Out of the carbapenem-resistant isolates, 76.25% Klebsiella spp. isolates were extensively drug-resistant (XDR) while 18.75% were pan drug-resistant (PDR), and 5% were multidrug-resistant (MDR). Regarding E. coli, 5% were PDR, 20% were MDR and 75% were XDR. More than one carbapenemase gene was detected in 99% of the isolates. In comparison between MAST-Carba plus discs and PCR results, sensitivity and specificity were (85.42–97.92%) in Klebsiella spp., and (69.64–100%) in E. coli, respectively. Moreover, a strong association was detected between both test results among Klebsiella spp. (p < 0.001) and E. coli (p = 0.012) isolates. Finally, ceftazidime-avibactam and aztreonam combination showed a synergistic effect in 98.8% of Klebsiella spp. and 95% of E coli. All 16 PDR isolates showed synergy. Conclusion This synergistic effect spots the light on new therapeutics for XDR and PDR CPE.

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Section: Discussionsupporting

confidence: 91%

“…Several recent studies have reported similar results, in which carbapenem resistance was more prevalent in Klebsiella spp. than E. coli [8,[14][15][16][17][18][19].…”

Section: Discussionmentioning

confidence: 99%

Ceftazidime-Avibactam plus aztreonam synergistic combination tested against carbapenem-resistant Enterobacterales characterized phenotypically and genotypically: a glimmer of hope

Taha

Kader²,

Shawky³

et al. 2023

Ann Clin Microbiol Antimicrob

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“…These urges evaluating and regular updates on the sensitivity/specificity values of the existed phenotypic and genotypic diagnostic methods of the most common circulating CPGN pathogens. Although, the phenotypic detection and molecular characterization of CPGN pathogens had been previously reported in literature [13][14][15][16], still more studies are urgently required to validate the laboratory performance (sensitivity/specificity/positive predictive value/negative predictive value) of the respective phenotypic methods and to correlate them with the different types of carbapenemase enzymes [1,14]. Therefore, in this study we aimed to evaluate the performance of four major phenotypic approaches namely MHT, mCIM, BCT, combined disk test by EDTA (CDT) for detecting CPGN pathogens.…”

Section: Introductionmentioning

confidence: 99%

Insights on the performance of phenotypic tests versus genotypic tests for the detection of carbapenemase-producing Gram-negative bacilli in resource-limited settings

et al. 2022

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Background: Carbapenemase-producing Gram-negative (CPGN) bacteria impose life-threatening infections with limited treatment options. Rigor and rapid detection of CPGN-associated infections is usually associated with proper treatment and better disease prognosis. Accordingly, this study aimed at evaluating the phenotypic methods versus genotypic methods used for the detection of such pathogens and determining their sensitivity/specificity values. Methods: A total of 71 CPGN bacilli (30 Enterobacterales and 41 non-glucose-fermenting bacilli) were tested for the carbapenemase production by the major phenotypic approaches including, the modified Hodge test (MHT), modified carbapenem inactivation method (mCIM), combined disk test by EDTA (CDT) and blue-carba test (BCT). The obtained results were statistically analyzed and correlated to the obtained resistant genotypes that were determined by using polymerase chain reactions (PCR) for the detection of the major carbapenemase-encoding genes covering the three classes (Class A, B, and D) of carbapenemases. Results: In comparison to PCR, the overall sensitivity/specificity values for detection of carbapenemase-producing organism were 65.62%/100% for MHT, 68.65%/100% for mCIM, 55.22%/100% for CDT and 89.55%/75% for BCT. The sensitivity/specificity values for carbapenemase-producing Enterobacterales were, 74%100% for MHT, 51.72%/ 100% for mCIM, 62.07%/100% for CDT and 82.75%/100% for BCT. The sensitivity/specificity values for carbapenemase-producing non-glucose fermenting bacilli were, 62.16%/100% for MHT, 81.57%/100% for mCIM, 50/100% for CDT and 94.74%/66.66% for BCT. Considering these findings, BCT possess a relatively high performance for the efficient and rapid detection of carbapenemase producing isolates. Statistical analysis showed significant association (p < 0.05) between blaNDM and/or blaVIM genotypes with MHT/CDT; blaKPC/blaGIM genotypes with CDT and blaGIM genotype with BCT. Conclusion: The current study provides an update on the performance of the phenotypic tests which are varied depending on the tested bacterial genera and the type of the carbapenemase. The overall sensitivity/specificity values for detection of CPO were 65.62%/100% for MHT, 68.65%/100% for mCIM, 55.22%/100% for CDT and 89.55%/75% for BCT. Based on its respective diagnostic efficiency and rapid turnaround time, BCT is more likely to be recommended in a resource-limited settings particularly, when molecular tests are not available.

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“…45 Furthermore, other studies stated that bla NDM was the predominant gene. 46,47 The major differences were likely due to different geographic region, antibiotics policy in different health care settings and methods of gene identification. 48 In our study, more than one resistance gene was detected in different isolates.…”

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confidence: 99%

Carbapenem-Resistant Gram-Negative Bacilli Causing Ventilator Associated Pneumonia: Study of MASTDISCS Combi Carba Plus for Detection of Carbapenemase Producing Enterobacterales

Hegazy¹,

Bahey²,

Hagar³

et al. 2022

IDR

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Background: Ventilator-associated pneumonia (VAP) caused by carbapenem-resistant gram-negative bacteria has been proven to be an escalating public health challenge in Egypt owing to its high mortality rate and raised health care costs. Purpose: Detection of carbapenem-resistant gram-negative bacilli among VAP patients, genotypic identification of carbapenemase genes in the isolated strains with evaluation of their impact on patient outcome and detection of carbapenemase-producing enterobacterales by MASTDISCS combi Carba plus disc system. Methods: Broncho-alveolar lavage fluid (BALF) and endotracheal aspirate were collected aseptically from clinically suspected VAP patients. Pathogen identification and antibiotic sensitivity testing were done. Carbapenemase-encoding genes (bla KPC , bla NDM , and bla OXA-48 ) were tested by PCR in all carbapenem-resistant gram-negative isolates. Performance of MASTDISCS combi Carba plus in isolated Enterobacterales was assessed in relation to the PCR results. Results: Eighty-three carbapenem-resistant gram-negative isolates were detected. The most frequent pathogens were Klebsiella pneumoniae, Acinetobacter baumannii and Pseudomonas aeruginosa representing 34.9%, 20.5% and 18.1%, respectively. bla KPC was the predominant gene. Patients with persistent mechanical ventilation less than 15 days and Pseudomonas aeruginosa infection were significantly associated with a higher death rate. MAST-Carba plus had the highest sensitivity, specificity, positive and negative predictive values for detecting OXA-48 carbapenemases representing 81.8%, 92.5%, 75% and 94.9%, respectively. Conclusion: Worse outcome in VAP patients was associated with carbapenem-resistant gram-negative bacilli. MASTDISCS combi Carba plus is an efficient simple method for identification of different carbapenemases among enterobacterales.

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Phenotypic and genotypic detection of carbapenemase production among gram negative bacteria isolated from hospital acquired infections

Abstract: Objectives: To identify the carbapenemase producing Gram-negative bacteria )GNB( by phenotypic methods and to confirm the presence of resistant genes using realtime polymerase chain reaction )PCR(. Methods:This was a prospective study carried out at the

Cited by 16 publications

References 24 publications

Ceftazidime-Avibactam plus aztreonam synergistic combination tested against carbapenem-resistant Enterobacterales characterized phenotypically and genotypically: a glimmer of hope

Ceftazidime-Avibactam plus aztreonam synergistic combination tested against carbapenem-resistant Enterobacterales characterized phenotypically and genotypically: a glimmer of hope

Insights on the performance of phenotypic tests versus genotypic tests for the detection of carbapenemase-producing Gram-negative bacilli in resource-limited settings

Carbapenem-Resistant Gram-Negative Bacilli Causing Ventilator Associated Pneumonia: Study of MASTDISCS Combi Carba Plus for Detection of Carbapenemase Producing Enterobacterales

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