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Background: The last-resort classes of antibiotics with the best success in treating severe Pseudomonas aeruginosa (P. aeruginosa) infections caused by drug-resistant P. aeruginosa are carbapenems. So, we aimed to assess the frequency of carbapenemresistant genes in P. aeruginosa. Methods: Samples isolated from critically ill patients at Intensive Care Units (ICUs) and surgical wards in Minia, Egypt were examined for imipenem-resistance phenotypically by Modified Hodge test (MHT) and Modified carbapenem inactivation method (mCIM) test and genotypically by PCR. Results: Fifty isolates (64%) of P. aeruginosa were resistant to carbapenems (imipenem and meropenem), of which: 16 (32%) were (MHT) positive and 26 (52 %) were (mCIM)- positive. Regarding resistance genes, blaIMP, blaVIM, and blaKPC were detected in 14%, 20%, and 48% of the carbapenem resistant Pseudomonas aeruginosa (CRPA) isolates; respectively, while blaGIM, blaSIM, blaNDM-1 and blaSPM-1 were not detected. Conclusion: There is a high prevalence of multi-drug resistant (MDR) strains of P. aeruginosa. Doctors should pay attention to carbapenem resistance. mCIM test was much more sensitive than MHT for phenotypic detection of CRPA isolates. blaKPC gene was the most frequently detected gene. [ABSTRACT FROM AUTHOR]

Background: Carbapenem-resistant Enterobacterales (CRE) are an urgent global public health problem. CRE infections are associated with high mortality and have limited available effective treatment. Carbapenemase enzymes are encoded by genes on mobile genetic elements, such as plasmids, which are highly transmissible between organisms and increase the potential spread of resistance. The study aim was to detect carbapenemase production in Gram negative bacilli by phenotypic (CarbaNP and mCIM only or in conjunction with eCIM) and genotypic (Xpert Carba-R) methods. Material and methods: The various clinical samples were processed as per standard recommended procedures. Identification and antibiotic susceptibility test were done by using GN cards and AST N280 & AST N281 cards of Vitek 2 Compact (bioMérieux) respectively. Phenotypic (CarbaNP and mCIM only or in conjunction with eCIM) and genotypic (Xpert Carba-R) methods were used for detection of carbapenemases. Result: 144 carbapenem-resistant Gram-negative bacilli isolated from various ICUs includes Klebsiella pneumoniae 52.7% (76/144) followed by Escherichia coli 18.05% (26/144) and 15.9% (23/144) Acinetobacter baumannii. Phenotypic test (CarbaNP and mCIM and or in conjunction with eCIM) showed sensitivity of 90%, 100% and 93.75% respectively. Genotypic test of 40 isolates showed predominant expression of NDM in 82.5% (33/40) isolates followed by OXA-48 in 40% (16/40). Conclusion: The study showed mCIM as the most useful diagnostic test with less economic burden to the patients. There is an urgent need for more sensitive, rapid, highly precise and accurate genotypic test which is less expensive and less labor-intensive.

Antimicrobial resistance (AMR) in Gram negative bacteria (GNB) has become a critical health concern across the globe. Unveiling of β-lactamase, extended spectrum β-lactamase (ESBL) and AmpC β-lactamase producing bacteria has led to the development of multidrug-resistant organisms (MDRO’s). Carbapenems are considered to be very effective in morbid infections caused by MDRO’s. Now, the upsurge of carbapenem resistance among GNB is an issue of concern as these infections are very difficult to treat. Rapid and reliable methods to detect these CPO’s in all Microbiology laboratories is essential to streamline the antimicrobial therapy. Accordingly, this study is conducted to determine the enormity of CPO’s among clinical isolates by various phenotypic tests along with differentiation of serine β-lactamases from metallo-β-lactamases. This is a Prospective Cross-sectional study meticulously planned & conducted for a period of one year. Among the 76 suspected Carbapenemase Producing Organisms (CPO’s), 42% were Klebsiella spp. followed by Escherichia coli (25%), Pseudomonas aeruginosa (24%), Citrobacter spp. (5%) and Proteus spp. (4%). Out of the total isolates 82% of the isolates were confirmed as CPO’s by Carba NP test, whereas 93% by mCIM test. 53% of the total isolates tested were Serine-β-lactamase producers and 41% were Metallo-β-lactamase producers. In conclusion, Carba NP test and mCIM in conjunction with eCIM test could be considered as reliable phenotypic diagnostic methods for carbapenemase detection to guide the clinicians for initiating antibiotic therapy.

Background: Carbapenems are frequently used as a last resort antibiotic in the treatment of infections due to multidrug-resistant Enterobacteriaceae. Their alarming increase worldwide is worrisome and is left with very restricted therapeutic alternatives. Objectives: This study compares the various phenotypic methods for detection of carbapenemase producers in Klebsiella species isolated from different clinical samples. Methods: All specimens received for culture and sensitivity were processed as per standard guidelines. Identification of Klebsiella spp. was done using biochemical tests as per standard guidelines. Carbapenemase production was detected phenotypic screening methods as per CLSI guidelines. Confirmation done by using Modified Hodge Test, Modified carbapenem inactivation method (mCIM) and EDTA-modified carbapenem inactivation method (eCIM) Results: Out of total 160 Klebsiella isolates test for carbapenemase production 101 (63.1%) was positive. MHT was positive in 76.2% isolates, whereas MCIM and ECIM were positive in 91.1% isolates. The sensitivity, specificity and PPV of MHT with MCIM were 82.6%, 88.9%, and 98.7% respectively, whereas sensitivity, specificity and PPV of ECIM with MCIM were 100%, 100%, and 100% respectively. Conclusion: MCIM in conjunction with ECIM test could be considered as more reliable phenotypic diagnostic methods for carbapenemase detection than the MHT in conjuction with the MCIM. [ABSTRACT FROM AUTHOR]

Antimicrobial resistance (AMR) in Gram negative bacteria (GNB) has become a critical health concern across the globe. Unveiling of b-lactamase, extended spectrum b-lactamase (ESBL) and AmpC b-lactamase producing bacteria has led to the development of multidrug-resistant organisms (MDRO's). Carbapenems are considered to be very effective in morbid infections caused by MDRO's. Now, the upsurge of carbapenem resistance among GNB is an issue of concern as these infections are very difficult to treat. Rapid and reliable methods to detect these CPO's in all Microbiology laboratories is essential to streamline the antimicrobial therapy. Accordingly, this study is conducted to determine the enormity of CPO's among clinical isolates by various phenotypic tests along with differentiation of serine b-lactamases from metallo-b-lactamases. This is a Prospective Cross-sectional study meticulously planned & conducted for a period of one year. Among the 76 suspected Carbapenemase Producing Organisms (CPO's), 42% were Klebsiella spp. followed by Escherichia coli (25%), Pseudomonas aeruginosa (24%), Citrobacter spp. (5%) and Proteus spp. (4%). Out of the total isolates 82% of the isolates were confirmed as CPO's by Carba NP test, whereas 93% by mCIM test. 53% of the total isolates tested were Serine-b-lactamase producers and 41% were Metallo-b-lactamase producers. In conclusion, Carba NP test and mCIM in conjunction with eCIM test could be considered as reliable phenotypic diagnostic methods for carbapenemase detection to guide the clinicians for initiating antibiotic therapy. [ABSTRACT FROM AUTHOR]

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We describe a case of carbapenem resistant E. coli isolated from urine in an 87-year-old woman with recurrent urinary tract infections. Using whole genome sequencing (WGS), we identified the carbapenem resistance mechanism to be a combination of ompC porin loss and plasmid-mediated AmpC gene blaCMY-2 , which was not detected by routine molecular and phenotypic carbapenemase assays. Our case raises a concern for the limitation of current CRE screening tools for emerging resistance mechanisms and demonstrates the utility of WGS as a better tool for characterization of CRE in the clinical setting.

Background: The aim of the study was to evaluate blood modified carbapenem inactivation method (mCIM) and automated susceptibility via VITEK2 compact system directly from positive blood culture bottles. Methods: The study was carried out using 54 strains positive for carbapenemase genes (OXA-48 type, KPC-type, NDM-type, and VIM-type) by multiplex PCR and 30 strains negative for these genes as controls, these strains were inoculated into blood culture bottles and then tested phenotypically for carbapenem resistance by mCIM and Vitek2 AST directly from the blood culture bottle. Results: MCIM was positive for all tested CPE strains and negative for the control strains with a 100% sensitivity, specificity and agreement with the PCR results. While vitek2 system had a sensitivity of 96%. Conclusion: Both methods save time when performed directly from the blood culture bottle that should guide appropriate administration of antimicrobials targeting bloodstream infections caused by carbapenemase producing Enterobacteriaceae. The mCIM is superior in being inexpensive requires basic reagents available in all microbiology laboratories with minimal processing compared to other tests and gives positive results with different carbapenemase classes.

Pseudomonas aeruginosa is inherently resistant to many drugs. It is now an emerging opportunistic pathogen of clinical relevance. The emergence of carbapenemases is another major concern. Initiation of appropriate therapy is of paramount importance thus highlighting the need of active surveillance for newer emerging resistance trends for better infection control. To study the resistance pattern of P. aeruginosa isolates obtained from lab specimens and to determine the production of ESBL and Carbapenemase among them. A hospital-based cross-sectional study was carried out in the Department of Microbiology, Government medical college Thrissur, among P. aeruginosa isolates obtained from lab specimens, from January 2018 – December 2018. 162 isolates were studied. Antimicrobial susceptibility testing was done by Kirby – Bauer disc diffusion method, extended-spectrum beta-lactamase (ESBL) production was confirmed by and phenotypic confirmatory disc diffusion test. Carbapenemase detection was done using the modified carbapenemase inactivation (mCIM) method. The obtained data was analysed. Among 162 isolates 83% were non-multidrug-resistant (MDR) strains and 17% were MDR strains. 22% of ceftazidime resistant isolates were ESBL producers. 6.2% isolates were resistant to imipenem. Among the imipenem resistant isolates, Carbapenemase production was seen in 30% isolates by mCIM test. According to our study, the most effective antibiotic against P. aeruginosa were imipenem and cefoperazone/sulbactam showing resistance in 6.3% and 6.9% isolates respectively. The diversity of antibiotic resistance mechanisms and the emergence of carbapenem resistance is a threat that limits treatment choices. This suggests the need for ongoing antimicrobial susceptibility studies in the future.

Introduction: The main concern in the 21st century is antibiotic resistance. Early detection of carbapenem-resistant Klebsiella pneumoniae infections can lower morbidity and death rates. Due to a shortage of alternative medicines, multidrug-resistant (MDR) and carbapenem-resistant Klebsiella pneumonia have become major therapeutic challenges in various countries. To ascertain the frequency of carbapenem-resistant Klebsiella pneumoniae isolates and their antibiogram profile is done in order to create therapeutic and infectioncontrol advice. Materials and Methods: A total of 366 Klebsiella pneumoniae isolates collected from various clinical samples are subjected to initial identification and they are screened and confirmed for carbapenemase production by phenotypic methods based on CLSI and for genotypic detection polymerase chain reaction is done. Results: Among them, 90 isolates showed carbapenem resistance. 90 isolates of carbapenem-resistant Klebsiella pneumoniae were subjected to phenotypic detection of carbapenemase enzyme synthesis using MHT, mCIM, and eCIM. Out of which, 75 isolates showed positive for MHT, 80 isolates showed positive for mCIM, 70 isolates showed positive for eCIM. In genotypic detection 80 isolates were positive for mCIM. PCR is performed for mCIM positive isolates in which the NDM gene was positive for 70 isolates and KPC the gene was positive for 10 isolates these PCR findings correlate with the phenotypic detection method mCIM and eCIM respectively. Discussion: In this study, confirmatory tests mCIM (Carbapenemase detection) were determined to be the most significant and reliable method. Also, it can be performed in routine microbiological testing. Since these correlate with results of PCR, this will aid in the detection of antibiotic resistance and judicious use of antibiotics. [ABSTRACT FROM AUTHOR]

Background: The aim of the study was to evaluate blood modified carbapenem inactivation method (mCIM) and automated susceptibility via VITEK2 compact system directly from positive blood culture bottles. Methods: The study was carried out using 54 strains positive for carbapenemase genes (OXA-48 type, KPC-type, NDM-type, and VIM-type) by multiplex PCR and 30 strains negative for these genes as controls, these strains were inoculated into blood culture bottles and then tested phenotypically for carbapenem resistance by mCIM and Vitek2 AST directly from the blood culture bottle. Results:MCIM was positive for all tested CPE strains and negative for the control strains with a 100% sensitivity, specificity and agreement with the PCR results. While vitek2 system had a sensitivity of 96%. Conclusion: Both methods save time when performed directly from the blood culture bottle that should guide appropriate administration of antimicrobials targeting bloodstream infections caused by carbapenemase producing Enterobacteriaceae. The mCIM is superior in being inexpensive requires basic reagents available in all microbiology laboratories with minimal processing compared to other tests and gives positive results with different carbapenemase classes. [ABSTRACT FROM AUTHOR]

Abstract Purpose Timely detection of carbapenemases is essential for developing strategies to control the spread of infections by carbapenem-resistant isolates. The purpose of this study was to determine the epidemiology of carbapenemase genes among carbapenem-resistant isolates of Acinetobacter baumannii, Klebsiella pneumoniae, and Escherichia coli. In addition, the efficacy of the modified Hodge test (MHT), Carba NP test, and modified carbapenem inactivation method (mCIM) were compared. Methods A total of 122 carbapenem-resistant clinical isolates including 77 K. pneumoniae, 39 A. baumannii, and six E. coli were collected from hospitalized patients. Three phenotypic methods, including the MHT, Carba NP test, and mCIM were used for investigation of carbapenemase production. In addition, polymerase chain reaction (PCR) was performed to detect carbapenemase-encoding genes. Result The sensitivity and specificity of the MHT were 75.0% and 100%, respectively. In addition, Carba NP displayed 80.8% sensitivity and 100% specificity, whereas the sensitivity and specificity were 90.4% and 100% for the mCIM test, respectively. Among carbapenem-resistant isolates, 70, 84, and 87 isolates exhibited positive results according to the MHT, Carba NP test, and mCIM, respectively. PCR indicated the presence of one or more carbapenemase genes in 119 of carbapenem-resistant isolates, with bla KPC and bla VIM being the most commonly encountered. Co-production of ‘KPC and OXA-48’, ‘KPC and VIM’, and ‘KPC and IMP’ was detected in three, nine, and seven isolates, respectively. Conclusion Our results confirm that the mCIM test is a useful tool for the reliable detection of carbapenemase activity in enterobacterial isolates, especially in clinical microbiological laboratories with limited resources.

Objectives: Many multidrug-resistant Gram-negative bacilli (MDR-GNB) harbour multiple β-lactamases. The aim of this study was to assess the impact of multiple β-lactamase carriage on the accuracy of susceptibility tests and extended-spectrum β-lactamase (ESBL) and carbapenemase confirmation methods. Methods: A total of 50 MDR-GNB, of which 29 carried multiple β-lactamases, underwent broth microdilution (BMD) and disk diffusion (DD) testing as well as confirmation tests for ESBLs and carbapenemases. Whole-genome sequencing (WGS) was used for β-lactamase gene identification. Results: Categorical agreement of BMD and DD testing results ranged from 86.5 to 97.7% for 10 β-lactam agents. BMD and DD algorithms for ESBL detection were highly variable; 6 of 8 positive strains carried an ESBL plus a carbapenemase or an AmpC enzyme, which may confound antimicrobial selection. The sensitivity and specificity of the modified carbapenem inactivation method (mCIM) were both 100%, whilst mCIM and EDTA-modified carbapenem inactivation method (eCIM) when used together to differentiate serine from metallo-β-lactamase carriage were both 96%. Xpert® Carba-R results (in vitro diagnostic test) were consistent with WGS results. Predicting phenotypic carbapenem resistance from WGS data overall showed 100% specificity but only 66.7% sensitivity for Enterobacterales isolates that were non-susceptible to imipenem and meropenem. Conclusions: Multiple β-lactamases in MDR-GNB does not impact DD results, the utility of mCIM/eCIM tests, or Xpert Carba-R results. However, ESBL algorithms produced inconsistent results and predicting carbapenem resistance from WGS data was problematic in such strains.

Abstract Background Carbapenemase-resistant Enterobacteriaceae (CRE) cause many serious infections resulting in increasing treatment cost, prolonged hospitalization, and mortality rate. Reduced expression and/or mutations of porins and the presence of carbapenemase promote Enterobacteriaceae survival under carbapenem treatments. Development of accurate methods for the detection of antimicrobial resistance is required not only for therapy but also to monitor the spread of resistant bacteria or resistance genes throughout the hospital and community. In this study, we aimed to evaluate the phenotypic methods, Modified Hodge test (MHT), modified carbapenem inactivation method (mCIM), and EDTA-CIM (eCIM) for the detection of carbapenemase-producing Enterobacteriaceae (CPE). Results The results showed that mCIM had a sensitivity of 100% and a specificity of 100%, whereas the MHT had a sensitivity of 84.8% and a specificity of 97.8% for the 195 CRE isolates tested (105 CPE and 90 non-CPE isolates). The sensitivity of the mCIM/eCIM to detect metallo-carbapenemases in this study was 89.3% and the specificity was 98.7% as compared to the genotypic PCR detection. Conclusions These findings indicate that the mCIM combined with eCIM is useful for detecting and distinguishing different types of carbapenemase in Enterobacteriaceae.

Carbapenemase-producing Enterobacterales (CPE) isolates increasingly carry oxacillinase-48 (OXA-48)-like enzymes encoded by bla OXA-48-like , which can confer high levels of carbapenem resistance. This aims to determine the prevalence of CPE and genetic variation among bla (CRE) isolates were recovered from clinical samples. CRE were evaluated using standard biochemical tests and MIC test strips. Carbapenemase production was assessed through the modified Hodge test (MHT), modified carbapenem inactivation method (mCIM), and EDTA-modified carbapenem inactivation method (eCIM). Detection of OXA-48-like -carrying isolates recovered from Prapokklao Hospital in Chanthaburi Province, Thailand in 2016-2017. In total, 122 carbapenem-resistant Enterobacterales (CRE) isolates were recovered from clinical samples. CRE were evaluated using standard biochemical tests and MIC test strips. Carbapenemase production was assessed through the modified Hodge test (MHT), modified carbapenem inactivation method (mCIM), and EDTA-modified carbapenem inactivation method (eCIM). Detection of bla OXA-48-like mutations was conducted via PCR and confirmed by Sanger sequencing. Among these CRE isolates, 72 (59.02%), 44 (36.07%), 3 (2.46%), and 3 (2.46%) were Klebsiella pneumoniae , respectively. The MHT identified carbapenemase production in 108 isolates (88.52%). Based on the mCIM, 81 isolates (66.39%) were carbapenemase producers. Seventy-three isolates (59.84%) were eCIM-positive, indicating metallo-β-lactamase production. Three distinct genetic variants of the Escherichia coli , Enterobacter aerogenes , and Enterobacter cloacae , respectively. The MHT identified carbapenemase production in 108 isolates (88.52%). Based on the mCIM, 81 isolates (66.39%) were carbapenemase producers. Seventy-three isolates (59.84%) were eCIM-positive, indicating metallo-β-lactamase production. Three distinct genetic variants of the bla OXA-48-like gene were identified among the isolates, including the wild-type and two point mutation types harboring the mutations E168Q and S171A (mutation type 1) and E168Q, S171A, and R214S (mutation type 2). Multiple-sequence alignment and in silico analysis revealed variation of R214 located in the β5-β6 loop. This study identified bla OXA-48-like point mutation groups and carbapenemase production, predominantly metallo-β-lactamases, among CRE isolates, especially K. pneumoniae and E. coli . These findings highlight the importance of implementing stringent infection control measures and active antimicrobial resistance surveillance to combat the spread of difficult-to-treat, metallo-β-lactamase-producing CRE in healthcare settings., Importance: In this study, we aimed to investigate genetic variation and CPE among bla OXA-48-like carrying isolates recovered from Prapokklao Hospital, Chanthaburi Province, Thailand, during 2016-2017. A total of 122 carbapenem-resistant Enterobacterales (CRE) were recovered from clinical samples in Prapokklao Hospital. All CRE samples were confirmed by standard biochemical tests and minimum inhibitory concentration (MIC) test strips (E-test). The carbapenemase production was determined using the modified Hodge test (MHT), the modified carbapenem inactivation method (mCIM), and EDTA-CIM (eCIM). Three single mutations (E168Q, S171A, and R214S) were characterized in this study. This mutation might reflect the hydrolysis of the modified β-lactam spectrum, especially carbapenem, by OXA-48-like. Our report provides evidence of the bla OXA-48-like point mutation and carbapenemase-producing phenotype of CRE detected in this healthcare setting. Effective control measures and active surveillance of drug resistance in nosocomial pathogens are crucial for controlling diseases associated with difficult-to-treat bacteria.

Background and aim Urinary tract infections represent a substantial portion of healthcare-associated infections due to E. coli and Klebsiella . Carbapenems are broad-spectrum antibiotics considered highly effective in treating infections caused by multidrug-resistant bacteria. Carbapenem-resistant  Enterobacteriaceae ( CRE), including carbapenem-producing E. coli and Klebsiella isolates, have become a major concern as they limit treatment options. The study aims to determine the prevalence of carbapenemase-producing E. coli and Klebsiella while also comparing the effectiveness of two detection methods, namely the modified carbapenem inactivation method (mCIM) and modified Hodge test (MHT). Materials and methods A cross-sectional study was conducted from July 2022 to June 2023 in a tertiary care hospital, in Karad, Satara, India. Three hundred urinary isolates of E. coli (150) and Klebsiella (150) were studied. These isolates were tested for antimicrobial susceptibility testing. Two phenotypic methods, the modified carbapenem inactivation method (mCIM) and the modified Hodge test (MHT), were used to study carbapenemase production. Results Out of three hundred isolates, carbapenemase production was detected in 72 isolates (24%) by the modified Hodge test (MHT) and in 111 isolates (37%) by the modified carbapenem inactivation method (mCIM). Among the MHT-positive isolates, 46 (63.8%) were identified as Klebsiella and 26 (36.1%) as E. coli . In contrast, of the mCIM-positive isolates, 68 (61.2%) were Klebsiella , and 43 (38.7%) were E. coli . A total of 41 Klebsiella (27.33%) and 25 E. coli (16.66%) isolates tested positive by both methods, highlighting variability in detection rates between the two methods. Conclusion This study observed MHT and mCIM to be accurate for the detection of carbapenemase among carbapenem-resistant isolates. However, the mCIM demonstrated greater sensitivity compared to the MHT., Competing Interests: Human subjects: Consent was obtained or waived by all participants in this study. Institutional Ethics Committee of Krishna Institute of Medical Sciences, Krishna Vishwa Vidyapeeth (Deemed To Be University), Karad issued approval 231/2023-2024. The authors affirm that this study adhered to ethical standards and received approval from Institutional Ethics Committee of Krishna Institute of Medical Sciences, Krishna Vishwa Vidyapeeth (Deemed To Be University), Karad, under protocol number 231/2023-2024. Animal subjects: All authors have confirmed that this study did not involve animal subjects or tissue. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Arumugam et al.)

Carbapenem-resistant Enterobacterales, particularly those that produce carbapenemases, pose a significant public health concern due to very limited treatment options. The timely identification of carbapenemase-producing Enterobacterales (CPE) is essential for putting in place efficient infection control measures and selecting appropriate antimicrobial therapies, thereby improving the clinical outcome of the patient. The purpose of this systematic review is to compare the diagnostic accuracy and practicality between two phenotypic tests, namely the modified carbapenem inactivation method (mCIM) and carbapenemase Nordmann-Poirel (Carba NP) test, in detecting carbapenemase production by Enterobacterales and thereby aiding the clinician in making a decision to choose an appropriate test for their phenotypic detection. This systematic review involved combining sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), accuracy, diagnostic odds ratio with 95% confidence interval (CIs), Forest plot for sensitivity and specificity, and plotting suitable summary receiver operating characteristic curve with the area under the curve. Of the 20 studies included in this review, the overall effect sizes of Carba NP and mCIM with 95% CIs were as follows: sensitivity, 91% (86-96%) and 97% (95-99%); specificity, 93% (88-97%) and 97% (93-100%); PPV, 97% and 98%; NPV, 79% and 90%; accuracy, 93% and 97%; diagnostic odds ratio, 1487.8879 and 8527.5541; and AUC, 0.85 and 1, respectively. In conclusion, the mCIM method showed superior sensitivity (97%), specificity (97%), and accuracy compared to the Carba NP test in detecting carbapenemase production, even though both these methods had a few technical limitations. The Carba NP test is rapid, affordable, and dependable, whereas mCIM is more accurate and cost-effective but time-consuming. We propose that both tests can be reliably used for screening of carbapenemase production in Enterobacterales, as endorsed by the Clinical and Laboratory Standards Institute even in resource-limited clinical laboratories, in the order of prioritizing the mCIM method first and then followed by the Carba NP test when situation demands expedited results., Competing Interests: Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Suriya R et al.)

The pressure-velocity coupling method of MCIM (Mass Corrected Interpolation Method) and different solution algorithms of this method were previously developed and tested for steady and unsteady incompressible flows. But the effect of under-relaxation factors in cell-face velocities and the main equations never have been investigated. On the other hand, this method and its different algorithms never have been compared with similar and more common methods in the formulation of primitive variables and non-staggered grid arrangements. In this paper, the accuracy, performance, and computational efficiency of the different solution algorithms of MCIM are compared with the well-known PWIM (Pressure Weighted Interpolation Method) of Rhie & Chow. In this study, a fully coupled, segregated approach without any pressure correction and SIMPLE-like segregated algorithms are proposed for two methods of MCIM and PWIM on the control volume-based finite element (CVFEM) framework. Also, for each method, the proper under-relaxation factors for the main equations and cell-face velocities are introduced. The accuracy and performance of the proposed algorithms are demonstrated by solving different steady and unsteady benchmark problems, and the results of both methods for different algorithms are compared. The results indicate that the both methods have spatial 2nd-order accuracy approximately and are not very different from each other. The results also show that the numerical dissipation of the MCIM is much less than PWIM. Comparing the computational cost of the different algorithms of both methods shows that the coupled algorithm of the MCIM for steady and unsteady problems with different time steps and various grid numbers is at least 10% better than other algorithms. [ABSTRACT FROM AUTHOR]

Pseudomonas aeruginosa is inherently resistant to many drugs. It is now an emerging opportunistic pathogen of clinical relevance. The emergence of carbapenemases is another major concern. Initiation of appropriate therapy is of paramount importance thus highlighting the need of active surveillance for newer emerging resistance trends for better infection control. To study the resistance pattern of P. aeruginosa isolates obtained from lab specimens and to determine the production of ESBL and Carbapenemase among them. A hospital-based cross-sectional study was carried out in the Department of Microbiology, Government medical college Thrissur, among P. aeruginosa isolates obtained from lab specimens, from January 2018 - December 2018. 162 isolates were studied. Antimicrobial susceptibility testing was done by Kirby - Bauer disc diffusion method, extended-spectrum beta-lactamase (ESBL) production was confirmed by and phenotypic confirmatory disc diffusion test. Carbapenemase detection was done using the modified carbapenemase inactivation (mCIM) method. The obtained data was analysed. Among 162 isolates 83% were non multidrug-resistant (MDR) strains and 17% were MDR strains. 22% of ceftazidime resistant isolates were ESBL producers. 6.2% isolates were resistant to imipenem. Among the imipenem resistant isolates, Carbapenemase production was seen in 30% isolates by mCIM test. According to our study, the most effective antibiotic against P. aeruginosa were imipenem and cefoperazone/sulbactam showing resistance in 6.3% and 6.9% isolates respectively. The diversity of antibiotic resistance mechanisms and the emergence of carbapenem resistance is a threat that limits treatment choices. This suggests the need for ongoing antimicrobial susceptibility studies in the future. [ABSTRACT FROM AUTHOR]

ABSTRACT Recently, various blaKPC-2 variants resistant to ceftazidime-avibactam have begun to emerge in clinical settings, but it is unclear which testing method is most appropriate for detecting these variants. Strains were subjected to antimicrobial susceptibility testing using the broth microdilution method. Four carbapenemase detection methods, modified carbapenem inactivation method (mCIM) and EDTA carbapenem inactivation method (eCIM), APB/EDTA (carbapenemase inhibitor APB [3-aminophenylboronic acid] and EDTA enhancement method), NG-test Carba 5, and GeneXpert Carba-R were used to try to detect KPC-2 variants in 19 Klebsiella pneumoniae isolates. Among those blaKPC-2 variants, blaKPC-33-, blaKPC-35-, blaKPC-71-, blaKPC-76-, blaKPC-78-, and blaKPC-79-positive isolates accounted for 26.3% (5/19), 15.8% (3/19), 5.3% (1/19), % 42.1% (8/19), 5.3% (1/19), and 5.3% (1/19), respectively. All 19 K. pneumoniae carrying blaKPC-2 variants showed resistance to ceftazidime-avibactam (MICs:16 to >64 mg/L), and 14 strains were susceptible to imipenem (MICs: 0.25 to 1 mg/L). None of the blaKPC-2 variants could be detected using either the mCIM or the APB/EDTA method, while five strains carrying blaKPC-2 variants (blaKPC-35, blaKPC-78, and blaKPC-79) tested KPC positive when using NG-test Carba 5. However, GeneXpert Carba-R was able to detect blaKPC-2 variants (harboring blaKPC-33, blaKPC-35, blaKPC-71, blaKPC-76, blaKPC-78, and blaKPC-79) carried by all 19 K. pneumoniae. The emergence of new KPC variants poses an increased challenge for carbapenemase detection methods, and laboratories should use the appropriate assays to accurately detect these variants. IMPORTANCE Carbapenemase detection is essential for the appropriate treatment of CRE infections. Several clinical laboratories have begun using relevant carbapenemase assays such as mCIM and eCIM, the APB/EDTA method, NG-test Carba 5, and GeneXpert Carba-R to detect carbapenemases. Nevertheless, some of these methods may have limitations for detecting blaKPC-2 variants. Additionally, there has been little relevant research on evaluate the differences between these standard methods for detecting blaKPC-2 variants. Therefore, we investigated the reliability of these classic methods for assessing 19 K. pneumoniae with blaKPC-2 variants. Our results showed that none of the blaKPC-2 variants could be detected using either the mCIM or APB/EDTA method, while five strains (harboring blaKPC-35, blaKPC-78,and blaKPC-79) tested KPC positive when using NG-test Carba 5. GeneXpert Carba-R could detect six blaKPC-2 variants carried by all 19 K. pneumoniae. This study may be valuable for clinical laboratories in their efforts to test for various blaKPC-2 variants.

ABSTRACT Rapid detection and reporting of carbapenemase-producing Enterobacterales (CPE) is one of the top priorities of clinical microbiology laboratories. The Clinical and Laboratory Standards Institute recommends the modified carbapenem inactivation method (mCIM) as the preferred method for this purpose, but it requires a broth incubation process which can be cumbersome. Here, we compared the performance of mCIM with three alternative rapid CPE detection methods against a collection of genetically defined CPE, with most carrying blaIMP, and non-CPE clinical isolates. The sensitivities of mCIM, simplified carbapenem inactivation method (sCIM), Rapidec Carba NP, and NG-Test Carba 5 were 98.0%, 54.9%, 90.2%, and 72.5%, whereas the specificities were 89.5%, 84.2%, 89.5%, and 100%, respectively. Modification of the interpretive criteria of sCIM increased its sensitivity to 88.2% and specificity to 89.5%. The results suggest that mCIM is currently the optimal method for CPE detection in an epidemiological setting where CPE-producing IMP group carbapenemase is predominant. While sCIM is easier to perform, it requires further validation before it can be widely adopted as an alternative to mCIM in the clinical laboratory. IMPORTANCE Simple identification methods for carbapenemase-producing Enterobacterales are required for the clinical laboratory. The simplified carbapenem inactivation method (sCIM) is a carbapenemase detection method that can be performed with less hands-on time than mCIM, but its sensitivity and specificity were suboptimal compared with other phenotypic detection methods when tested against a collection of IMP-producing CPE. Insufficient inactivation of imipenem from inadequate inoculation was suspected as the cause. While sCIM is easier to perform, it requires optimization before it can be widely adopted as an alternative to mCIM in the clinical laboratory.

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. [ABSTRACT FROM AUTHOR]

Introduction: The rising incidence of carbapenem resistance in Enterobacterales and Pseudomonas aeruginosa is a concern. Since carbapenemase production is the primary resistance mechanism, detecting and identifying the genes responsible for it is crucial to effectively monitor its spread., Objective: This study aims to detect positivity for the modified carbapenem inactivation method (mCIM) and ethylenediaminetetraacetic acid (EDTA)-carbapenem inactivation method (eCIM) for the detection of carbapenemase-producing Enterobacterales and Pseudomonas aeruginosa ., Methods: Methods: A cross-sectional study was carried out at a tertiary care hospital, including 250 clinical isolates of Enterobacterales and Pseudomonas aeruginosa . These isolates exhibited resistance to at least one of the carbapenems as determined by the VITEK AST 2 System (bioMérieux, USA). The isolates were subjected to mCIM testing, and those that tested positive were further tested using eCIM. The results were interpreted in accordance with the guidelines provided by the Clinical and Laboratory Standards Institute (CLSI) 2023., Results: Out of the total 250 carbapenem-resistant Enterobacterales and Pseudomonas aeruginosa isolates, 151 (60.4%) were Klebsiella pneumonia, 44 (17.6%) were Escherichia coli, 10 (4.0%) were Enterobacter cloacae , 6 (2.4%) were Providencia spp ., 4 (1.6%) were Serratia marcescens , 4 (1.6%) were Proteus mirabilis and 31 (12.4%) were Pseudomonas aeruginosa . Positivity for the mCIM was observed in 96% (240 out of 250) of the isolates. Of the mCIM-positive isolates, 234 (97.5%) also tested positive for eCIM, indicating metallo-β-Lactamase (MLB) production. A statistically significant association was found between both mCIM and eCIM positivity and the degree of resistance to carbapenem (p<0.05) . Conclusion: This study shows that the inexpensive method, a combination of mCIM and eCIM assists in differentiating between serine carbapenemase producers and MLB producers, thereby guiding the selection of appropriate therapy and useful in infection control in resource-limited settings., Competing Interests: Human subjects: Consent was obtained or waived by all participants in this study. Institutional Ethics Committee at Kalinga Institute of Medical Sciences, Bhubaneswar issued approval KIIT/KIMS/IEC/1344/2023. The study was approved by the Institutional Ethics Committee (reference no. KIIT/KIMS/IEC/1344/2023. Animal subjects: All authors have confirmed that this study did not involve animal subjects or tissue. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Verma et al.)

Introduction: Carbapenems are broad spectrum β Lactam antibiotics & are the last resort to control infections caused by gram negative bacteria. The increasing resistance to these antibiotics is an alarming sign. CRE (Carbapenem resistant Enterobacteriaceae) is reported due to acquisition of carbapenemase genes or association with decreased outer membrane permeability with β lactamases with weak carbapenemase activity. Methods: Total 123 culture positive blood samples from our tertiary care hospital were included in which carbapenem resistance was identified and the resistant strains were assessed for carbapenemase production by Modified Hodge Test (MHT) & Modified Carbapenemase inactivation method (mCIM) simultaneously. Results: Out of total 896 blood samples received, 123 isolates were members of Enterobacteriaceae family. The maximum isolates were Escherichia coli 39(31.70%) next was Klebsiella pneumoniae, Klebsiella oxytoca, Klebsiella aerogenes, Citrobacter freundii. Carbapenem resistance was seen in 19(15.44%) isolates. The positivity rate by MHT was 11 (57.89%) while by mCIM was 17(89.47%). Conclusion: Prevalence of carbapenem resistance was 15.44%.

Purpose: Timely detection of carbapenemases is essential for developing strategies to control the spread of infections by carbapenem-resistant isolates. The purpose of this study was to determine the epidemiology of carbapenemase genes among carbapenem-resistant isolates of Acinetobacter baumannii, Klebsiella pneumoniae, and Escherichia coli. In addition, the efficacy of the modified Hodge test (MHT), Carba NP test, and modified carbapenem inactivation method (mCIM) were compared. Methods: A total of 122 carbapenem-resistant clinical isolates including 77 K. pneumoniae, 39 A. baumannii, and six E. coli were collected from hospitalized patients. Three phenotypic methods, including the MHT, Carba NP test, and mCIM were used for investigation of carbapenemase production. In addition, polymerase chain reaction (PCR) was performed to detect carbapenemase-encoding genes. Result: The sensitivity and specificity of the MHT were 75.0% and 100%, respectively. In addition, Carba NP displayed 80.8% sensitivity and 100% specificity, whereas the sensitivity and specificity were 90.4% and 100% for the mCIM test, respectively. Among carbapenem-resistant isolates, 70, 84, and 87 isolates exhibited positive results according to the MHT, Carba NP test, and mCIM, respectively. PCR indicated the presence of one or more carbapenemase genes in 119 of carbapenem-resistant isolates, with blaKPC and blaVIM being the most commonly encountered. Co-production of ‘KPC and OXA-48’, ‘KPC and VIM’, and ‘KPC and IMP’ was detected in three, nine, and seven isolates, respectively. Conclusion: Our results confirm that the mCIM test is a useful tool for the reliable detection of carbapenemase activity in enterobacterial isolates, especially in clinical microbiological laboratories with limited resources. [ABSTRACT FROM AUTHOR]

Background: Carbapenem antibiotics are important therapeutic agents in the health care setting, they are frequently used as an empiric therapy for life-threatening infections as well as infections with multi-drug-resistant gram-negative bacilli. Carbapenemaseproducing Carbapenem-Resistant Enterobacteriaceae (CRE) are a significant public health challenge worldwide. The detection of carbapenemases productions in CRE strains is performed by phenotypic and genotypic methods. The phenotypic methods target carbapenemases production but provide no guidance regarding the specific carbapenemases types, while the genotypic diagnosis has the benefit of determining the exact mechanism conferring carbapenems resistance. Aim: Improvement of the antibiotic policy and infection control strategies in Suez Canal University Hospitals in Ismailia; through adequate detection of carbapenem resistance in the hospitals. Methods: All the CRE isolates were tested by the phenotypic methods (mCIM & eCIM) test to detect carbapenemases production, and screened by the conventional PCR for the presence of five carbapenemase genes, namely blaKPC, blaIMI, blaVIM, blaNDM, blaOXA-48. Results: The study showed that (53/155) 34.1% of the Enterobacteriaceae isolates were carbapenems resistant. Carbapenemases activity was detected in (36/53) 67.9% of the examined CRE isolates using mCIM test (20/36)37.8% showed Metallocarbapenemases and (16/36) 30.2% showed Serine- carbapenemases by eCIM test. 60.4% (32/53) were sensitive to colistin. While by PCR, all the isolates (100%) harbor one or more carbapenemases genes. (51/53) 96.2% were proved to harbor blaOXA-48 gene, (47/53) 88.7% were proved to harbor blaNDM gene, (28/53) 52.8%, were proved to harbor blaVIM,gene, the percentage of blaIMI, blaKPC isolation was (17/53) 32.1%, (4/53)7.5% respectively. Conclusion: High frequencies of carbapenemase genes among CRE isolates. [ABSTRACT FROM AUTHOR]

Rapid and accurate detection can help optimize patient treatment and improve infection control against nosocomial carbapenemase-producing organisms (CPO). In this study, a total of 217 routine clinical isolates (Enterobacterales and A. baumannii), including 178 CPOs and 39 non-CPOs, were tested to evaluate the performance of six phenotypic carbapenemase detection and classification assays, i.e., BD Phoenix CPO detect panel, Rapidec Carba-NP, O.K.N detection kit, and three carbapenem inactivation methods (CIMs; mCIM, eCIM, sCIM). The overall detection sensitivity and specificity were 98.78% (95.21–99.79%) and 79.49% (63.06–90.13%), respectively, for the BD phoenix CPO P/N test; 91.93% (86.30–95.45%) and 100% (88.83–100%), respectively, for the Rapidec Carba-NP; 98.06% (94.00–99.50%) and 97.44% (84.92–99.87%), respectively, for mCIM; and 96.89% (92.52–98.85%) and 94.87% (81.37–99.11%), respectively, for sCIM. The classification sensitivity and specificity for the BD phoenix CPO Ambler test, the O.K.N detection kit, and the mCIM and eCIM were 56.71% (48.75–64.34%) and 94.87% (81.37–99.11%), 99.28% (95.43–99.96%) and 100% (88.83–100%), and 92.90% (87.35–96.23%) and 97.44% (84.92–99.87%), respectively. All detection assays were reliable in detecting carbapenemase. However, the Rapidec Carba-NP and mCIM were insufficient in detecting OXA-48-like enzymes. The BD phoenix CPO detect panel had a strong ability to detect carbapenemase but failed to classify 48/59 (81.36%) KPC, 8/52 (15.38%) NDM, 8/22 (36.36%) OXA-23-like, and 6/11 (54.55%) dual enzymes. The O.K.N detection kit accurately detected and differentiated KPC, NDM, and OXA-48-like enzymes existing alone or in combination. The results of this study will support reliable laboratory work tools and promote therapeutic and infection control decisions.

Copyright of Journal of Modern Laboratory Medicine is the property of Journal of Modern Laboratory Medicine Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In over eighty years, despite successive antibiotics discoveries, the rapid advent of multidrug resistance among bacterial pathogens has jolted our misapprehension of success over them. Resistance is spreading faster than the discovery of new antibiotics/antimicrobials. Therefore, the search for better antimicrobials/additives becomes prudent. A water-soluble curcumin derivative (Curaq) was synthesised, employing a Cu (I) catalysed 1, 3-cyclo addition reaction; it has been evaluated as a potential treatment for multidrug-resistant isolates and as an antibiotic adjuvant for meropenem against hypervirulent multidrug-resistant Klebsiella pneumoniae isolates. We also investigated its solubility and effect over carbapenemase activity. Additionally, we investigated its impact on the AcrAB-TolC system. We found that Curaq inhibited bacterial growth at a minimal concentration of 16 µg/mL; at a 32 µg/mL concentration, it killed bacterial growth completely. Only nine (9.4%) Klebsiella isolates were sensitive to meropenem; however, after synergising with Curaq (8 µg/mL), 85 (88.54%) hvKP isolates became sensitive to the drug. The Curaq also inhibited the AcrAB-TolC efflux system at 1 µg/mL concentration by disrupting the membrane potential and causing depolarisation. The kinetic parameters obtained also indicated its promise as a carbapenemase inhibitor. These results suggest that Curaq can be an excellent drug candidate as a broad-spectrum antibacterial and anti-efflux agent.

Introduction: Carbapenems have become one of the last resort of antimicrobials. But in last few years, Carbapenem Resistant Enterobacteriaceae (CRE) have been reported worldwide. Various phenotypic tests have been proposed for detection of carbapenemase activity including the newer modified Carbapenem Inactivation Method (mCIM) as advised by Clinical Laboratory Standard Institute (CLSI) 2017 guidelines. Aim: Detection of CRE from clinical specimens with new mCIM method and its comparative evaluation with phenotypic and genotypic methods. Materials and Methods: Study was conducted between January 2017 and December 2017 at KIMS, Karad. Total 66 CRE, isolated from 1634 clinical specimens and identified by VITEK 2 (Biomerieux, France) were included in the study. Phenotype screening was done by mCIM (CLSI 2017) method and was compared with Modified Hodge test (MHT) and Combined Disc Test (CDT) methods. Klebsiella pneumoniae ATCC BAA-1705 and Klebsiella pneumoniae ATCC BAA-1706 were used as positive and negative controls respectively. Molecular confirmation of these isolates for carbapenemase producing genes blaNDM-1, blaOXA-48, blaKPC was done by multiplex Polymerase Chain Reaction (PCR) study. Results: Klebsiella pneumoniae (n=35) outnumbered the other bacterial species among 66 CRE included in the study. mCIM was positive for 65 (98.48%) out of 66 isolates while MHT and CDT was positive for 50 (75.75%) and 59 (89.39%) of CRE isolates respectively. All the CRE isolates showed presence of at least one carbapenemase producing gene. Conclusion: The mCIM method is simple, less subjective, cost effective, reproducible and most sensitive method and plays important role in detection and prevention of spread of CRE, thereby, reducing morbidity and mortality, especially where there is lack of automation and molecular diagnostic facility.

Introduction: Carbapenems are broad spectrum ß Lactam antibiotics & are the last resort to control infections caused by gram negative bacteria. The increasing resistance to these antibiotics is an alarming sign. CRE (Carbapenem resistant Enterobacteriaceae) is reported due to acquisition of carbapenemase genes or association with decreased outer membrane permeability with ß lactamases with weak carbapenemase activity. Methods: Total 123 culture positive blood samples from our tertiary care hospital were included in which carbapenem resistance was identified and the resistant strains were assessed for carbapenemase production by Modified Hodge Test (MHT) & Modified Carbapenemase inactivation method (mCIM) simultaneously. Results: Out of total 896 blood samples received, 123 isolates were members of Enterobacteriaceae family. The maximum isolates were Escherichia coli 39(31.70%) next was Klebsiella pneumoniae, Klebsiella oxytoca, Klebsiella aerogenes, Citrobacter freundii. Carbapenem resistance was seen in 19(15.44%) isolates. The positivity rate by MHT was 11 (57.89%) while by mCIM was 17(89.47%). Conclusion: Prevalence of carbapenem resistance was 15.44%. [ABSTRACT FROM AUTHOR]

Aim: The purpose of the study was to determine the epidemiology of carbapenemase genes among carbapenem-resistant Enterobacteriaceae and evaluate the Carba NP and modified carbapenem inactivation method (mCIM) tests in their detection. Materials and Methods: A total of 287 nonduplicated Enterobacteriaceae isolates, which were at least resistant to one of the carbapenems, were identified and detected for carbapenemase genes by multiplex PCR covering blaKPC, blaNDM, blaVIM, blaIMP, and blaOXA-48-like. All positive genes were then sequenced. These isolates were phenotypically tested for the production of carbapenemases by mCIM and Carba NP tests to evaluate the efficacy of these methods. Results: Seven species of carbapenem-resistant isolates mainly Klebsiella pneumoniae, Escherichia coli, and Enterobacter cloacae were detected. Of these isolates, three families of carbapenemase genes, including blaNDM (blaNDM-1, -4, -5, -9), blaOXA (blaOXA-48, -181, -232), and blaIMP-14, were found. Of these, 223 (77.70%) carried at least one of the carbapenemase genes. The blaNDM was detected in 160/223 (71.75%) isolates, of which 153/160 (95.63%) were the blaNDM-1. Three types of the blaOXA-48-like group, blaOXA-48, blaOXA-181, and blaOXA-232, were found, 91/104 (87.5%) harbored the blaOXA-232. In addition, 25.11% (56/223) of the carbapenemase-producing isolates harbored a combination of blaNDM and blaOXA-48-like. Phenotypic detection methods, mCIM and Carba NP, showed 100% sensitivity and specificity to blaNDM, blaIMP-14, and blaOXA-48, while the mCIM was positive in all blaOXA-181 and blaOXA-232 isolates, only 12.5% (1/8) and 28.95% (11/38), respectively, were detected by the Carba NP test. Conclusions: This study revealed a unique prevalence of carbapenemase genes in Bangkok, Thailand, as well as demonstrated the efficacy and limitation of phenotypic detection methods of carbapenemase in the area where blaNDM-1 and blaOXA-232 were predominant. [ABSTRACT FROM AUTHOR]

NG-Test CARBA 5 (NG-Biotech) is a rapid in vitro multiplex immunoassay for the phenotypic detection and differentiation of the "big five" carbapenemase families (KPC, OXA-48-like, VIM, IMP, and NDM). Version 2 of this assay was evaluated alongside the Xpert Carba-R assay (Cepheid, Inc.), the modified carbapenem inactivation method (mCIM), and the CIMTris assay, with a collection of carbapenem-resistant non-fermenting Gram-negative bacilli comprising 138 Pseudomonas aeruginosa and 97 Acinetobacter baumannii isolates. Whole-genome sequencing (WGS) was used as the reference standard. For P. aeruginosa , NG-Test CARBA 5 produced an overall percentage agreement (OPA) with WGS of 97.1%, compared with 92.8% forXpert Carba-R and 90.6% for mCIM. For A. baumannii , as OXA-type carbapenemases (non-OXA-48) are not included, both the NG-Test CARBA 5 and Xpert Carba-R only had an OPA of 6.2%, while the CIMTris performed well with an OPA of 99.0%. The majority of A. baumannii isolates (95.9%) tested falsely positive for IMP on NG-Test CARBA 5; no IMP genes were found on WGS. No clear cause was found for this phenomenon; a cross-reacting protein antigen unique to A. baumannii is a possible culprit. NG-Test CARBA 5 performed well for carbapenemase detection in P. aeruginosa . However, results from A. baumannii isolates should be interpreted with caution., Competing Interests: The authors declare no conflict of interest.

Copyright of Journal of Modern Laboratory Medicine is the property of Journal of Modern Laboratory Medicine Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract: Measurements of gas temperature profiles in a large-scale test furnace are made by inverting the measured spectral data at 4.3μm band with inversion algorithms. A 3.4m-long stainless steel tube is employed as the test furnace through which flue gas flows. Three inversion algorithms are tested: modified constrained inversion method (MCIM), base function-based inversion method (BFIM) and BFIM-based MCIM (BCIM). The correlated-k (CK)-based WNB model is employed for calculation of spectral intensities during the inversion process. The overall performances of algorithms are scrutinized with the inversion results. To verify the accuracy, the inverted temperatures are compared with measured ones using thermocouples. BFIM is good for initial guess and MCIM is good for fine touch, while BCIM gives fairly good results for all cases considered. Thus, BCIM is considered to be applicable, with good accuracy and capability, to inverse problems in large-scale furnaces. [Copyright &y& Elsevier]

The spectral remote sensing (SRS) inversion technique to determine the complex, line-of-sight temperature distribution from gas emission data at CO2 4.3 μm is analytically investigated with two proposed algorithms. The modified constrained inversion method (MCIM) and the base function based inversion method (BFIM) are extensively tested to evaluate their convergence characteristics for practical applications. The MCIM shows good applicability only to relatively simple profiles, while the BFIM gives reasonable estimations even for multi-peak profiles provided that appropriate base functions are selected. Further, simultaneous inversion of temperature and concentration is tried and it is found to be accurately achieved when there is an inter-correlation between them. [Copyright &y& Elsevier]

Antimicrobial resistance (AMR) has been a leading issue for human health globally threatening the achievement of several of the Sustainable Development Goals (SDGs). Originated from Bacillus cereus , carbapenemases phenotype has been considered to be a major concern in AMR. In this study, the AMR identification rate of P. aeruginosa isolates and infections in FAHJU showed an obvious upward trend from 2012 to 2016. All 88 carbapenem-resistant P. aeruginosa strains were screened for carbapenemase phenotype by modified Carbapenem Inactivation Method (mCIM), and these results of mCIM were compared with traditional PCR results. The isolates of P. aeruginosa and infected patients showed obvious upward trend from 2012 to 2016. The drug resistance to common clinical antibiotics was serious that the clinical rational use of antibiotics should be strengthened, which is in accordance with the Global Antimicrobial Resistance and Use Surveillance System (GLASS) report. In comparison, the results of mCIM showed that 18 out of 88 CRPA strains were carbapenemase positive, which were completely consistent with the results yielded by PCR method. Therefore, it is convinced that this mCIM methodology is a simple and quick method for detected carbapenemases producing P. aeruginosa and has a potential capability in carbapenemases phenotype of pathogen like B. cereus , which will undoubtedly aid in the AMR therapy.

Rapid and accurate detection can help optimize patient treatment and improve infection control against nosocomial carbapenemase-producing organisms (CPO). In this study, a total of 217 routine clinical isolates (Enterobacterales and A. baumannii), including 178 CPOs and 39 non-CPOs, were tested to evaluate the performance of six phenotypic carbapenemase detection and classification assays, i.e., BD Phoenix CPO detect panel, Rapidec Carba-NP, O.K.N detection kit, and three carbapenem inactivation methods (CIMs; mCIM, eCIM, sCIM). The overall detection sensitivity and specificity were 98.78% (95.21–99.79%) and 79.49% (63.06–90.13%), respectively, for the BD phoenix CPO P/N test; 91.93% (86.30–95.45%) and 100% (88.83–100%), respectively, for the Rapidec Carba-NP; 98.06% (94.00–99.50%) and 97.44% (84.92–99.87%), respectively, for mCIM; and 96.89% (92.52–98.85%) and 94.87% (81.37–99.11%), respectively, for sCIM. The classification sensitivity and specificity for the BD phoenix CPO Ambler test, the O.K.N detection kit, and the mCIM and eCIM were 56.71% (48.75–64.34%) and 94.87% (81.37–99.11%), 99.28% (95.43–99.96%) and 100% (88.83–100%), and 92.90% (87.35–96.23%) and 97.44% (84.92–99.87%), respectively. All detection assays were reliable in detecting carbapenemase. However, the Rapidec Carba-NP and mCIM were insufficient in detecting OXA-48-like enzymes. The BD phoenix CPO detect panel had a strong ability to detect carbapenemase but failed to classify 48/59 (81.36%) KPC, 8/52 (15.38%) NDM, 8/22 (36.36%) OXA-23-like, and 6/11 (54.55%) dual enzymes. The O.K.N detection kit accurately detected and differentiated KPC, NDM, and OXA-48-like enzymes existing alone or in combination. The results of this study will support reliable laboratory work tools and promote therapeutic and infection control decisions. [ABSTRACT FROM AUTHOR]