scholarly journals Comparison of Different Phenotypic Tests versus PCR in the Detection of Carbapenemase-Producing Pseudomonas aeruginosa Isolates in Hamadan, Iran

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Masoumeh Beig ◽  
Mohammad Taheri ◽  
Mohammad Reza Arabestani
Keyword(s):  
Pseudomonas Aeruginosa ◽  
High Sensitivity ◽  
Test Method ◽  
Clinical Samples ◽  
Predictive Values ◽  
Carbapenem Resistant ◽  
Accurate Detection ◽  
Phenotypic Methods ◽  
Sensitivity Specificity ◽  
Phenotypic Tests

In recent years, the prevalence of carbapenem-resistant Pseudomonas aeruginosa isolates has become a worldwide concern. Rapid and accurate detection of carbapenemase-producing P. aeruginosa isolates is so important. The aim of this study was to evaluate the performance of the phenotypic methods such as Modified Hodge test (MHT), CarbaNP (CNPt), combined double-disk synergy test (CDDT), and carbapenem inactivation method (CIM) for rapid and accurate detection of clinical carbapenemase production of P. aeruginosa isolates. This study was performed on 97 P. aeruginosa strains, which were isolated from clinical samples in Hamadan hospitals, western Iran in 2017-2018. Antibiotic susceptibility testing was performed using disk diffusion and minimum inhibitory concentration (MIC) by E-test method. We evaluated the performance of MHT, CarbaNP, CDDT, and CIM tests in comparison to polymerase chain reaction (PCR) for the detection of carbapenemase-producing isolates. Additionally, the presence of carbapenem-resistant genes was investigated using the PCR method. Our findings showed that the highest resistance was to cefoxitin (94.8%). Moreover, among the carbapenem antibiotics, the highest resistance was to imipenem (49.4%). Among the 49 carbapenem-resistant isolates, 42 (85.7%) isolates were MIC positive. The results of phenotypic tests showed that CarbaNP, CIM, CDDT, and MHT tests were positive in (48/49, 97.95%), (46/49, 93.87%), (27/49, 57.44%), and (25/49, 53.19%) of isolates, respectively. CarbaNP and CIM tests showed high sensitivity, specificity, positive predictive values (PPV), and negative predictive values (NPV) compared to PCR in P. aeruginosa isolates. CarbaNP and CIM tests are highly sensitive and specific tests for identifying carbapenemase-producing P. aeruginosa isolates.

scholarly journals Evaluation of HiCrome KPC Agar for the Screening of Carbapenem-Resistant Enterobacterales Colonization in the ICU Setting of a Tertiary Care Hospital

2021 ◽  
Author(s):  
Ashoka Mahapatra ◽  
K Nikitha ◽  
Sutapa Rath ◽  
Bijayini Behera ◽  
Kavita Gupta
Keyword(s):  
Tertiary Care ◽  
High Sensitivity ◽  
Care Hospital ◽  
Predictive Values ◽  
Klebsiella Pneumoniae Carbapenemase ◽  
Carbapenem Resistant ◽  
Rectal Swabs ◽  
Control And Prevention ◽  
Indian Setting ◽  
Sensitivity Specificity

Abstract Background Spread of carbapenem-resistant Enterobacterales (CRE) is a significant concern in intensive care unit (ICU) settings. Approaches to routine screening for CRE colonization in all ICU patients vary depending on institutional epidemiology and resources. The present study was aimed to evaluate the performance of HiCrome Klebsiella pneumoniae carbapenemase (KPC) agar for the detection of CRE colonization in ICU settings taking the Centers for Disease Control and Prevention (CDC) recommended method as reference. Methods Two-hundred and eighty rectal swabs (duplicate) from 140 patients were subjected to CRE detection in HiCrome KPC agar and MacConkey agar (CDC criteria). Results Using CDC method, total 41 CRE isolates were recovered comprising of 29 E scherichia coli, 11 Klebsiella, and 1 Enterobacter spp. On the other hand, 49 isolates of CRE recovered from 140 rectal swabs using HiCrome KPC agar, out of which 33 were E. coli, 15 Klebsiella, and 1 Enterobacter sp. Statistical Analysis Sensitivity, specificity, negative, and positive predictive values of CRE screening by HiCrome KPC agar were found to be 100% (91.4–100), 91.9% (84.8–95.8), 83.6% (70.9–91.4), and 100% (95.9–100), respectively, taking the CDC recommended method as reference. Conclusion HiCrome KPC agar has high sensitivity in screening CRE colonization. Further studies are needed to establish its applicability for detecting the predominant circulating carbapenemases in the Indian setting.

Evaluation of LAMP assay using phenotypic tests and conventional PCR for detection of bla NDM-1 and bla KPC genes among carbapenem-resistant clinical Gram-negative isolates

2013 ◽  
Vol 62 (10) ◽  
pp. 1540-1544 ◽  
Author(s):  
Rachana Solanki ◽  
Lavanya Vanjari ◽  
Nagapriyanka Ede ◽  
Akhila Gungi ◽  
Amarendranath Soory ◽  
...  
Keyword(s):  
Point Of Care ◽  
Lamp Assay ◽  
Cost Effective ◽  
Turnaround Time ◽  
Conventional Pcr ◽  
Gram Negative ◽  
Carbapenem Resistant ◽  
Phenotypic Methods ◽  
Sensitivity Specificity ◽  
Phenotypic Tests

Carbapenem-resistant pathogens cause infections associated with significant morbidity and mortality. This study evaluates the use of the loop-mediated isothermal amplification (LAMP) assay for rapid and cost-effective detection of bla NDM-1 and bla KPC genes among carbapenem-resistant Gram-negative bacteria in comparison with conventional PCR and existing phenotypic methods. A total of 60 carbapenem-resistant clinical isolates [Escherichia coli (15), Klebsiella pneumoniae (22), Acinetobacter baumannii (23)] were screened for the presence of carbapenemases (bla KPC and bla NDM-1) using phenotypic methods such as the modified Hodge test (MHT) and combined disc test (CDT) and molecular methods such as conventional PCR and LAMP assay. In all, 47/60 isolates (78.3 %) were MHT positive while 48 isolates were positive by CDT [46.6 % positive with EDTA, 30 % with 3′ aminophenylboronic acid (APB) plus EDTA and 1.6 % with APB alone]. Isolates showing CDT positivity with EDTA or APB contained bla NDM-1 and bla KPC genes, respectively. bla NDM-1 was present as a lone gene in 28 isolates (46.7 %) and present together with the bla KPC gene in 19 isolates (31.7 %). Only one E. coli isolate had a lone bla KPC gene. The LAMP assay detected either or both bla NDM-1 and bla KPC genes in four isolates that were missed by conventional PCR. Neither gene could be detected in 12 (20 %) isolates. The LAMP assay has greater sensitivity, specificity and rapidity compared to the phenotypic methods and PCR for the detection of bla NDM-1 and bla KPC. With a turnaround time of only 2–3 h, the LAMP assay can be considered a point-of-care assay.

scholarly journals Prevalence of metallo-β-lactamase genes among Pseudomonas aeruginosa isolated from various clinical samples in China

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Wei Wang ◽  
Xiaoya Wang
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antibiotic Susceptibility ◽  
Ethylenediaminetetraacetic Acid ◽  
Carbapenem Resistance ◽  
Opportunistic Pathogen ◽  
Detection Methods ◽  
Clinical Samples ◽  
Routine Practice ◽  
Carbapenem Resistant ◽  
High Prevalence

AbstractBackgroundPseudomonas aeruginosa is an opportunistic pathogen which is associated with nosocomial infections and causes various diseases including urinary tract infection, pneumonia, soft-tissue infection and sepsis. The emergence of P. aeruginosa-acquired metallo-β-lactamase (MBL) is most worrisome and poses a serious threat during treatment and infection control. The objective of this study was to identify antibiotic susceptibility, phenotypic detection of MBL production and to determine the prevalence of MBL genes in carbapenem-resistant P. aeruginosa isolated from different clinical samples.MethodsA total of 329 non-duplicate P. aeruginosa isolated from various clinical samples from two hospitals in China between September 2017 and March 2019 were included in this study. Phenotypic detection of MBL was performed by the combined detection method using imipenem and imipenem-ethylenediaminetetraacetic acid (EDTA) discs. MBL-encoding genes including blaVIM-1, blaVIM-2, blaIMP-1, blaIMP-2, blaSPM-1, blaSIM, blaNDM-1 and blaGIM were detected by polymerase chain reaction (PCR).ResultsOf the 329 P. aeruginosa, majority of the isolates were resistant to imipenem (77.5%) followed by meropenem (64.7%). Of the 270 P. aeruginosa isolates tested, 149 (55.2%) isolates were found to be positive for MBL detection. Of the different samples, 57.8% (n = 26) of P. aeruginosa isolated from blood were found to be positive for MBL production. Of the various MBL genes, blaIMP-1 (28.2%) was the most predominant gene detected followed by blaVIM-2 (18.8%), blaVIM-1 (16.1%), blaNDM-1 (9.4%), blaIMP-2 (6.7%), blaSIM (6.0%), blaSPM-1 (4.0%) and blaGIM (1.3%) genes.ConclusionsThe high resistance of P. aeruginosa toward imipenem and meropenem and the high prevalence of blaIMP-1 and blaVIM-2 set the alarm on the increasing, perhaps the increased, carbapenem resistance. In addition to routine antibiotic susceptibility testings, our results emphasize the importance of both the phenotypic and genotypic MBL detection methods in routine practice for early detection of carbapenem resistance and to prevent further dissemination of this resistant pathogen.

scholarly journals Investigation of Metallo-Beta-Lactamases in Carbapenem Resistant Pseudomonas aeruginosa Strains by Phenotypic and Genotypic Methods

2020 ◽  
Vol 25 (3) ◽  
pp. 301-307
Author(s):  
M. Duygu Aksoy ◽  
H. Murat Tuğrul
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Ethylenediaminetetraacetic Acid ◽  
Carbapenem Resistance ◽  
Beta Lactamase ◽  
Bacterial Strains ◽  
Beta Lactamases ◽  
Carbapenem Resistant ◽  
Synergy Test ◽  
Phenotypic Tests ◽  
Positive Controls

Introduction: Carbapenem resistant Pseudomonas aeruginosa strains cause serious problems in treatment. A large number of identified metallo-beta-lactamase (MBL) enzymes produced by P. aeruginosa are one of the most important mechanisms in resistance to carbapenems. MBL genes are located on the chromosome or plasmid, and they can easily spread between different bacterial strains. The activities of these enzymes are zinc-dependent, and they are inhibited by ethylenediaminetetraacetic acid (EDTA). Therefore, this advantage is used in MBL identification tests. In this study, it was aimed to determine MBL among P. aeruginosa strains. Materials and Methods: MBL existence was investigated in 35 P. aeruginosa strains accepted to be mildly susceptible/resistant to any of the carbapenem group of antibiotics through phenotypic and genotypic methods. Phenotypic tests were performed as double disk synergy test (DDST), combined disk diffusion tests (CDDT) by using 0.1 M and 0.5 M EDTA, MBL E-test, and modified Hodge test (MHT). blaIMP, blaVIM, blaGIM, blaSIM, blaSPM genes and blaNDM gene were investigated by multiplex polimerase chain reaction (PCR) and PCR, respectively. Escherichia coli ATCC 25922 and P. aeruginosa ATCC 27853 standard bacteria were used in tests. VIM-1, VIM-2, IMP-13, SPM-1, NDM-1 type MBL-producing P. aeruginosa strains were used as positive controls. Results: Among the carbapenems resistant P. aeruginosa isolates, positivity of MBL was found as 54.2% by MBL E-test, 42.8% by DDST, 94.2% and 37.1% by CDDT method using 0.5 M and 0.1 M EDTA, respectively. Modified Hodge test and genotypic method did not detect MBL. Conclusion: In order to correctly evaluate the results of the phenotypic method, the investigation of resistance genes by molecular methods is also required. The most common metallo-beta-lactamase enzymes responsible for resistance to carbapenem in Pseudomonas were not observed. It was thought that different mechanisms might be responsible for the identified carbapenem resistance.

scholarly journals Evaluation of different phenotypic tests for detection of metallo-β-lactamases in imipenem-resistant Pseudomonas aeruginosa

2017 ◽  
Vol 9 (04) ◽  
pp. 249-253 ◽  
Author(s):  
Rohit Sachdeva ◽  
Babita Sharma ◽  
Rajni Sharma
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Large Scale ◽  
Wide Spectrum ◽  
Carbapenem Resistance ◽  
Resistance Mechanisms ◽  
Clinical Samples ◽  
Resistant Strains ◽  
Synergy Test ◽  
Phenotypic Tests ◽  
Simple Screening

Abstract PURPOSE: Pseudomonas aeruginosa causes a wide spectrum of infections including bacteremia, pneumonia, urinary tract infection, etc., Metallo-beta-lactamase (MBL) producing P. aeruginosa is an emerging threat and cause of concern as they have emerged as one of the most feared resistance mechanisms. This study was designed to know the prevalence of MBL production in P. aeruginosa and to evaluate the four phenotypic tests for detection of MBL production in imipenem-resistant clinical isolates of P. aeruginosa. METHODS: Totally, 800 isolates of P. aeruginosa isolated from various clinical samples were evaluated for carbapenem resistance and MBL production. All imipenem-resistant strains were tested for carabapenemase production by modified Hodge test. Screening for MBL production was done by double-disc synergy test and combined disc test (CDT). Confirmation of MBL production was done by the E-test (Ab BioDisk, Solna, Sweden). RESULTS: Out of the 800 isolates of P. aeruginosa, 250 isolates were found resistant to imipenem. Based on the results of E-test, 147 (18.37%) isolates of P. aeruginosa were positive for MBL production. The CDT has the highest sensitivity and specificity for the detection of MBL production as compared to other tests. CONCLUSION: The results of this study are indicative that MBL production is an important mechanism of carbapenem resistance among P. aeruginosa. Use of simple screening test like CDT will be crucial step toward large-scale monitoring of these emerging resistant determinants. Phenotypic test for MBL production has to be standardized, and all the isolates should be routinely screened for MBL production.

scholarly journals Comparative Evaluation of Four Phenotypic Methods for Detection of Class A and B Carbapenemase-Producing Enterobacteriaceae in China

2018 ◽  
Vol 56 (8) ◽  
Author(s):  
Menglan Zhou ◽  
Danchen Wang ◽  
Timothy Kudinha ◽  
Qiwen Yang ◽  
Shuying Yu ◽  
...  
Keyword(s):  
Predictive Value ◽  
Comparative Evaluation ◽  
Detection Sensitivity ◽  
Detection Methods ◽  
Content Type ◽  
Class A ◽  
Carbapenem Resistant ◽  
Class B ◽  
Phenotypic Methods ◽  
Sensitivity Specificity

ABSTRACT The objective of this study was to evaluate the performance of four phenotypic methods in the detection of carbapenemase-producing Enterobacteriaceae (CPE) in China. We evaluated the performance of four carbapenemase detection methods, the modified Hodge test (MHT), the Carba NP test, the meropenem hydrolysis assay (MHA) with 1- and 2-h incubation, and the modified carbapenem inactivation method (mCIM) with meropenem, imipenem, and ertapenem, on 342 carbapenem-resistant Enterobacteriaceae isolates (CRE) in China. PCR was used as the gold standard. The 2-h-incubation MHA performed the best in carbapenemase detection (overall sensitivity, specificity, positive predictive value, and negative predictive value all 100%). Second was the Carba NP test, with a sensitivity of 99.6%. The 1-h-incubation MHA performed poorly in Klebsiella pneumoniae carbapenemase (KPC) detection (sensitivity, 71.3%). For mCIM, the best performance was observed with the meropenem disk. The MHT exhibited the worst performance, with a specificity of 88.8%. All assays except 1-h-incubation MHA, which failed to identify 68 KPC-2s, had a sensitivity of >98% in the detection of 172 KPCs. Likewise, all assays had a sensitivity of >95% in the detection of 70 class B carbapenemases, except for MHT (82.9%). The 2-h-incubation MHA significantly improved the accuracy in CPE detection compared with that for 1-h incubation and performed the best in the detection of class A and B carbapenemases. Our findings suggest that the MHA is the most practical assay for carbapenemase detection. For those who cannot afford the associated equipment, both the Carba NP test and mCIM are good alternatives with regard to the practical requirements of time and cost.

scholarly journals Searching for the Fetal Alcohol Behavioral Phenotype

2020 ◽  
Vol 7 ◽  
pp. 2333794X2094133
Author(s):  
Gideon Koren ◽  
Asher Ornoy
Keyword(s):  
High Sensitivity ◽  
Behavioral Phenotype ◽  
Narrative Review ◽  
Screening Tools ◽  
Fetal Alcohol ◽  
Predictive Values ◽  
Published Evidence ◽  
Sensitivity Specificity ◽  
Fetal Alcohol Spectrum

This narrative review presents the emerging published evidence on the existence of a phenotypic behavior in children with fetal alcohol spectrum behavior. Such a phenotype, exhibiting high sensitivity, specificity, and predictive values, may assist clinicians and families in identifying children who often miss some of the information needed for full diagnosis, but who may benefit from these screening tools in mobilizing help to these youngsters and their families.

scholarly journals Reproducibility and validity of portable haemoglobinometer for the diagnosis of anaemia in children under the age of 5 years

2020 ◽  
Vol 9 ◽  
Author(s):  
Alessandra da Silva Pereira ◽  
Inês Rugani Ribeiro de Castro ◽  
Flávia Fioruci Bezerra ◽  
José Firmino Nogueira Neto ◽  
Ana Carolina Feldenheimer da Silva
Keyword(s):  
Venous Blood ◽  
Intraclass Correlation ◽  
Age Groups ◽  
Capillary Blood ◽  
Test Method ◽  
Automated System ◽  
Accuracy Rate ◽  
Predictive Values ◽  
Sensitivity Specificity ◽  
Good Agreement

Abstract Portable haemoglobinometers have been used in order to estimate the prevalence of anaemia in diverse settings. However, few studies have been conducted to evaluate their performance in children of different age groups in distinct epidemiological contexts. To evaluate the reproducibility and reliability of a portable haemoglobinometer for the diagnosis of anaemia in children <5 years Hb was measured in the venous blood of 351 children <5 years by an automated system (standard method) and in three capillary blood samples, using a portable haemoglobinometer (HemoCue®; test method). The reproducibility of the device and of the test method was evaluated using the intraclass correlation coefficient (ICC) (Hb in its continuous form), κ and prevalence-adjusted bias-adjusted κ (PABAK) (categorised variable: anaemia: yes/no). For test method validation, Bland–Altman analyses were performed and sensitivity, specificity, accuracy rate, positive predictive value (PPV) and negative predictive values (NPV) were calculated. The haemoglobinometer presented good device reproducibility (ICC = 0·79) and reasonable method reproducibility (puncture, collection and reading) (ICC = 0·71). Superficial and fair agreement (κ) and good agreement (PABAK) were observed among the diagnoses obtained through the test method. The prevalence of anaemia was 19·1 and 19·7 % using the standard and the test method, respectively, with no statistically significant differences. The test method presented higher specificity (87·7 %) and NPV (88·3 %) than sensitivity (50·7 %) and PPV (49·3 %), and intermediary accuracy rate (57·8 %). HemoCue® showed good device reproducibility and reasonable method reproducibility, as well as good performance in estimating the prevalence of anaemia. Nevertheless, it showed a fair reliability and low individual diagnostic accuracy.

scholarly journals Accuracy of a new hysteroscopic method in the assessment of tubal patency: Hysteroscopic Chromotubation

2018 ◽  
Vol 24 (2) ◽  
pp. 82
Author(s):  
Burak Yucel ◽  
Emine Demirel ◽  
Sefa Kelekci ◽  
Kerem Doga Seckin ◽  
Osama Shawki
Keyword(s):  
Methylene Blue ◽  
Cohort Study ◽  
Gold Standard ◽  
Uterine Cavity ◽  
High Sensitivity ◽  
Office Hysteroscopy ◽  
Predictive Values ◽  
Tubal Patency ◽  
Infertile Women ◽  
Sensitivity Specificity

<p><strong>Objective</strong></p><p>The aim of this study was to evaluate the diagnostic accuracy of hysteroscopic chromopertubation (HCT) in the assessment of tubal patency by comparing its results with laparoscopic chromopertubation (LCT).</p><p><strong>Study Design</strong></p><p>The population of this prospective cohort study consisted of both fertile and infertile women. Sixty-four women were included to the study. HCT was assessed by the observation of the transport of highly concentrated methylene blue from uterine cavity to tubal ostia. The results of HCT were compared with the results of LCT as a gold standard. The accuracy of HCT, sensitivity, specificity, positive and negative predictive values in diagnosing tubal patency were calculated.<strong></strong></p><p><strong>Results</strong></p><p>The results of HCT and LCT were evaluated for right and left tubes, separately. One hundred and twenty-eight tubes were determined. Sensitivity, specificity, positive and negative predictive values for HCT were; 85.85%, 59.09%, 91% and 46.43%, respectively.</p><p><strong>Conclusion </strong></p><p>This study’s result showed that HCT had high sensitivity and moderate specificity values in the assessment of tubal patency. HCT during office hysteroscopy could give the chance to practitioners to assess tubal patency without subjecting the patient to multiple procedures.<strong></strong></p>

scholarly journals Molecular characterization of resistance mechanisms in Pseudomonas aeruginosa isolates resistant to carbapenems

2018 ◽  
Vol 11 (12) ◽  
pp. 935-943 ◽  
Author(s):  
Mona Shaaban ◽  
Ahmed Al-Qahtani ◽  
Mohammed Al-Ahdal ◽  
Rasha Barwa
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Real Time ◽  
Real Time Pcr ◽  
Treatment Options ◽  
Carbapenem Resistance ◽  
Pulse Field ◽  
Diffusion Method ◽  
Clinical Samples ◽  
Pcr Analysis ◽  
Carbapenem Resistant

Introduction: Emergence of carbapenem resistance in Pseudomonas aeruginosa increases the therapeutic dilemma. In this study, we investigated various mechanisms involved in the resistance of P. aeruginosa clinical isolates to carbapenems. Methodology: P. aeruginosa isolates were isolated from different clinical samples. The antimicrobial susceptibility was evaluated by disc diffusion method. Carbapenemases were detected among carbapenem resistant isolates. Expression level of mexB and oprD was determined by real-time PCR. Molecular relatedness among isolates was detected based on pulse-field gel electrophoresis (PFGE). Results: Ninety P. aeruginosa isolates were purified from clinical specimens. High levels of resistance to imipenem and meropenem were detected in 16 isolates. PCR analysis of carbapenemases indicated the prevalence of Verona integron-encoded metallo-beta-lactamase (VIM); four isolates produced only VIM enzymes (VIM-1 or VIM-2), while the remaining twelve co-produced both VIM-1 or VIM-2 and NDM enzymes. Additionally, real-time PCR analysis elucidated high expression levels of mexB in seven of the carbapenem resistant isolates and low expression of oprD in seven isolates. The identified carbapenem-resistant isolates were clustered into eleven PFGE profiles where clusters E1 and E2 involved isolates exhibiting multiple carbapenemase genes (blaNDM-1, blaVIM-1 and blaVIM-2). Conclusion: Various mechanisms underlying carbapenem resistance have been detected in our P. aeruginosa cohort of isolates. Emergence of P. aeruginosa as a reservoir of multiple carbapenemases is increasing over time limiting the treatment options to this serious infection. This increases the urgency for infection control practices to reduce the incidence of this infection.

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