scholarly journals Development and evaluation of a LAMP assay for differentiating Carbapenem-Resistant Acinetobacter baumannii clinical strains harboring blaOXA-23

2019 ◽  
Author(s):  
Puyuan Li ◽  
Wenkai Niu ◽  
Yun Fang ◽  
Dayang Zou ◽  
Huiying Liu ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Sensitivity And Specificity ◽  
Antimicrobial Susceptibility ◽  
Susceptibility Testing ◽  
Surrogate Marker ◽  
Lamp Assay ◽  
Antimicrobial Susceptibility Testing ◽  
Clinical Samples ◽  
Lamp Method ◽  
Carbapenem Resistant

Abstract Background Acinetobacter baumannii (A. baumannii) is an important nosocomial pathogen in hospital-acquired infections, and the resistance to carbapenems has been observed increasingly worldwide. Oxacillinase produced by blaOXA-23 is one of the predominant carbapenem resistance mechanisms in A. baumannii, which is highly prevalent worldwide, especially in China. The rapid identification of blaOXA-23 may give a valuable hint for the administration of directed antimicrobial therapy. Method In this study, we aimed to develop a LAMP-based detection for the blaOXA-23 gene; clinical samples of A. baumannii were used to determine the sensitivity and specificity of this method compared to phenotypic antimicrobial susceptibility testing and traditional PCR method. MLST was performed to investigate the epidemiology of A. baumannii bacterial population. Results Compared to the antimicrobial susceptibility testing, the sensitivity and specificity of LAMP in detecting blaOXA-23 was 88.4% and 97.7%, respectively. However, the LAMP method was found to be much simpler and the result could be available in a shorter period (within 60 minutes) when compared to conventional PCR and phenotypic susceptibility testing. The 113 isolates could be clustered into 30 sequence types (STs), and majority (83/113) of these strains belong to clonal complex 92 (CC92), which is also the dominant CC in the China. Conclusion The LAMP-based method detected blaOXA-23 in a much simpler way, by which could provide timelier results for differentiating the carbapenem-resistant Acinetobacter baumannii than conventional methods. Consequently, blaOXA-23 may potentially serving as surrogate marker for the presence of CRAB in patients with serious infections in clinic.

Occurrence of Non-Fermenting Gram-Negative Bacilli and Their In Vitro Susceptibility Pattern by Vitek 2 at a Tertiary Care Teaching Hospital – An Observational Study

2021 ◽  
Vol 8 (8) ◽  
pp. 429-434
Author(s):  
Atit Dineshchandra Shah ◽  
Urvashi Natubhai Limbachia ◽  
Bhavin K. Prajapati ◽  
Lata Patel ◽  
Dharati Tusharbhai Shah ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Multidrug Resistance ◽  
Antimicrobial Susceptibility ◽  
Susceptibility Testing ◽  
Tertiary Care ◽  
Carbapenem Resistance ◽  
Antimicrobial Susceptibility Testing ◽  
Clinical Samples ◽  
Gram Negative ◽  
Vitek 2

BACKGROUND Non fermenting gram-negative bacilli (NFGNB) are a group of heterogenous, aerobic and non-sporing saprophytic bacteria, found as commensals in humans and other animals primarily causing opportunistic healthcare-associated infections. They are innately resistant to many antibiotics and are known to acquire resistance by various mechanisms. They pose a particular difficulty for the healthcare community because multidrug resistance is common and increasing among them and a number of strains have now been identified that exhibit pan drug resistance. This study was conducted to isolate and identify various non-fermenter gram negative bacilli (NFGNB), to study their antibiotic sensitivity pattern and their clinical significance from various clinical samples. METHODS A study was undertaken from March 2019 to February 2020 to isolate NFGNB from various clinical samples received for culture and sensitivity in the department of microbiology in a tertiary care hospital, Ahmedabad. Non lactose fermenting colonies on MacConkey agar plates were further processed by Vitek 2 to identify them and to study their antimicrobial susceptibility testing (AST). RESULTS A total of 2010 NFGNB were isolated from various clinical samples and their AST was evaluated by Vitek 2. Pseudomonas aeruginosa (52.7 %) and Acinetobacter baumannii (36.5 %) were the most common NFGNB isolated. Carbapenem resistance was 93 % for Acinetobacter species and 61 % for Pseudomonas species. CONCLUSIONS Accurate and rapid identification and antimicrobial susceptibility testing of NFGNB help in early initiation of appropriate antimicrobial therapy and proper management of patients thereby help in reducing emergence of MDR strains of NFGNB, mortality and overall hospital stay. KEYWORDS NFGNB – Non-Fermenting Gram-Negative Bacilli, Multidrug Resistance, Pan Drug Resistance, Carbapenem Resistance

scholarly journals A Biosensor Platform for Rapid Antimicrobial Susceptibility Testing Directly From Clinical Samples

2011 ◽  
Vol 185 (1) ◽  
pp. 148-153 ◽  
Author(s):  
Kathleen E. Mach ◽  
Ruchika Mohan ◽  
Ellen Jo Baron ◽  
Mei-Chiung Shih ◽  
Vincent Gau ◽  
...  
Keyword(s):  
Antimicrobial Susceptibility ◽  
Susceptibility Testing ◽  
Antimicrobial Susceptibility Testing ◽  
Clinical Samples

scholarly journals Cefiderocol Antimicrobial Susceptibility Testing against Multidrug-Resistant Gram-Negative Bacilli: a Comparison of Disk Diffusion to Broth Microdilution

2020 ◽  
Vol 59 (1) ◽  
pp. e01649-20 ◽  
Author(s):  
C. Paul Morris ◽  
Yehudit Bergman ◽  
Tsigedera Tekle ◽  
John A. Fissel ◽  
Pranita D. Tamma ◽  
...  
Keyword(s):  
Antimicrobial Susceptibility ◽  
Susceptibility Testing ◽  
Multidrug Resistant ◽  
Antimicrobial Susceptibility Testing ◽  
Disk Diffusion ◽  
Broth Microdilution ◽  
Gram Negative ◽  
Content Type ◽  
Carbapenem Resistant ◽  
Alternative Approach

ABSTRACTAntimicrobial susceptibility testing (AST) of cefiderocol poses challenges because of its unique mechanism of action (i.e., requiring an iron-depleted state) and due to differences in interpretative criteria established by the Clinical and Laboratory Standards Institute (CLSI), U.S. Food and Drug Administration (FDA), and European Committee on Antimicrobial Susceptibility Testing (EUCAST). Our objective was to compare cefiderocol disk diffusion methods (DD) to broth microdilution (BMD) for AST of Gram-negative bacilli (GNB). Cefiderocol AST was performed on consecutive carbapenem-resistant Enterobacterales (CRE; 58 isolates) and non-glucose-fermenting GNB (50 isolates) by BMD (lyophilized panels; Sensititre; Thermo Fisher) and DD (30 μg; research-use-only [RUO] MASTDISCS and FDA-cleared HardyDisks). Results were interpreted using FDA (prior to 28 September 2020 update), EUCAST, and investigational CLSI breakpoints (BPs). Categorical agreement (CA), minor errors (mE), major errors (ME), and very major errors (VME) were calculated for DD methods. The susceptibilities of all isolates by BMD were 72% (FDA), 75% (EUCAST) and 90% (CLSI). For DD methods, EUCAST BPs demonstrated lower susceptibility at 65% and 66%, compared to 74% and 72% (FDA) and 87% and 89% (CLSI) by HardyDisks and MASTDISCS, respectively. CA ranged from 75% to 90%, with 8 to 25% mE, 0 to 19% ME, and 0 to 20% VME and varied based on disk, GNB, and BPs evaluated. Both DD methods performed poorly for Acinetobacter baumannii complex. There is considerable variability when cefiderocol ASTs are interpreted using CLSI, FDA, and EUCAST breakpoints. DD offers a convenient alternative approach to BMD methods for cefiderocol AST, with the exception of A. baumannii complex isolates.

scholarly journals Performance of Vitek 2 for Antimicrobial Susceptibility Testing of Acinetobacter baumannii, Pseudomonas aeruginosa, and Stenotrophomonas maltophilia with Vitek 2 (2009 FDA) and CLSI M100S 26th Edition Breakpoints

2016 ◽  
Vol 55 (2) ◽  
pp. 450-456 ◽  
Author(s):  
April M. Bobenchik ◽  
Eszter Deak ◽  
Janet A. Hindler ◽  
Carmen L. Charlton ◽  
Romney M. Humphries
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Acinetobacter Baumannii ◽  
Antimicrobial Susceptibility ◽  
Stenotrophomonas Maltophilia ◽  
Susceptibility Testing ◽  
Antimicrobial Susceptibility Testing ◽  
Broth Microdilution ◽  
Content Type ◽  
Vitek 2 ◽  
Improved Performance

ABSTRACTThe performances of Vitek 2 AST-GN69 and AST-XN06 cards were compared to Clinical and Laboratory Standards Institute (CLSI) reference broth microdilution (BMD) for 99 isolates ofPseudomonas aeruginosa, 26Acinetobacter baumanniiisolates, and 11Stenotrophomonas maltophiliaisolates. In total, 15 antimicrobials were evaluated, with 11 forP. aeruginosa, 14 forA. baumannii, and 2 forS. maltophilia. Categorical agreement (CA) was assessed using both Vitek 2 breakpoints and 2016 CLSI M100S 26th edition breakpoints. The essential agreement values forP. aeruginosa,A. baumannii, andS. maltophiliawere 99.5%, 99.2%, and 100%, respectively. The CA values forP. aeruginosa,A. baumannii, andS. maltophiliawere 94.1%, 92.7%, and 95.5%, respectively, by the Vitek 2 breakpoints, and 93.4%, 92.3%, and 95.5%, respectively, by the CLSI breakpoints. Overall, the Vitek 2 performance was comparable to that of BMD using both Vitek 2 breakpoints and 2016 CLSI M100S 26th edition breakpoints. Improved performance was noted for the reformulated piperacillin-tazobactam and imipenem found on the AST-GN69 card, with no very major or major errors noted when using the CLSI breakpoints.

scholarly journals Performance Evaluation of BD Phoenix NMIC-413 Antimicrobial Susceptibility Testing Panel for Imipenem, Meropenem, and Ertapenem Against Clinical Carbapenem-Resistant and Carbapenem-Susceptible Enterobacterales

2021 ◽  
Vol 8 ◽  
Author(s):  
Jingjia Zhang ◽  
Peiyao Jia ◽  
Ying Zhu ◽  
Ge Zhang ◽  
Yingchun Xu ◽  
...  
Keyword(s):  
Antimicrobial Susceptibility ◽  
Susceptibility Testing ◽  
Antimicrobial Susceptibility Testing ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
Screening Methods ◽  
Major Error ◽  
Disk Diffusion Method ◽  
Suitable Alternative ◽  
Carbapenem Resistant

Purpose: The infection of carbapenem-resistant Enterobacterales (CRE) has become a major clinical and healthcare problem worldwide. The screening methods of CRE have been extensively developed but still need improving [e.g., tests with accurate and simple minimum inhibitory (MICs)]. In this study, the performance of the BD Phoenix NMIC-413 AST panel was evaluated against clinical CRE and carbapenem-susceptible Enterobacterales (CSE) in China. The panel was first evaluated in the Chinese clinical lab.Methods: Antimicrobial susceptibility testing of 303 clinical Enterobacterales isolates were conducted by broth microdilution (BMD), Phoenix NMIC-413 AST panel, and disk diffusion method for imipenem, ertapenem, and meropenem. Considering BMD is a gold standard, essential agreement (EA), categorical agreement (CA), minor error (MIE), major error (ME), and very major error (VME) were determined according to CLSI guidelines. CA and EA > 90%, ME <3%, and VME <1.5% were considered as acceptable criteria. Polymerase chain reaction and sanger sequencing were performed to determine the β-lactamase genotypes of CRE isolates.Results: Three hundred and three isolates included 195 CREs and 108 CSEs were enrolled according to the BMD-MIC values of three carbapenems. Tested CREs showing 100 blaKPC−2-positive organisms, 31 blaIMP-positive organisms, 28 blaNDM-positive organisms, 5 blaVIM-positive organisms, 2 both blaIMP and blaVIM-positive organisms, 2 blaOXA−48-positive organisms, and 27 isolates without carbapenemase genes. For the Phoenix NMIC-413 method, CA and EA rates >93%, MIE rates <5%, ME rates <1.75%, and VME rates were 0%, across the three drugs. For the disk diffusion method, the CA rates for three drugs were all >93%, while the MIE and ME rates were all <5 and <3%, respectively. VME rate was 3.28% for imipenem, exceeded the cut-off value specified by CLSI M52, 0 and 0.56% for ertapenem and meropenem, separately.Conclusion: Based on the genomic data, the detection of CRE and CSE was more reliable using the BD Phoenix NMIC-413 panel compared to the BMD and disk approaches. Therefore, our study supports the use of BD Phoenix NMIC-413 panel as a suitable alternative to BMD for the detection of carbapenem resistant isolates in a clinical setting.

scholarly journals Multicenter Evaluation of the New Etest Gradient Diffusion Method for Piperacillin-Tazobactam Susceptibility Testing of Enterobacterales, Pseudomonas aeruginosa, and Acinetobacter baumannii Complex

2019 ◽  
Vol 58 (2) ◽  
Author(s):  
Sergio García-Fernández ◽  
Yohann Bala ◽  
Tom Armstrong ◽  
María García-Castillo ◽  
Carey-Ann D. Burnham ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Acinetobacter Baumannii ◽  
Antimicrobial Susceptibility ◽  
Susceptibility Testing ◽  
Hospital Setting ◽  
Antimicrobial Susceptibility Testing ◽  
International Standards ◽  
Diffusion Method ◽  
Content Type ◽  
Gradient Diffusion

ABSTRACT Piperacillin-tazobactam (P/T) is a β-lactam–β-lactamase inhibitor combination frequently used in the hospital setting. Etest is a gradient diffusion method that represents an alternative to broth microdilution (BMD) for performing antimicrobial susceptibility testing. We conducted a multicenter evaluation of the performance of the new P/T Etest compared to that of BMD following U.S. Food and Drug Administration (FDA) and International Standards Organization (ISO) standard ISO 20776-2 criteria using Clinical and Laboratory Standards Institute (CLSI)-FDA and European Committee on Antimicrobial Susceptibility Testing (EUCAST) interpretive breakpoints, respectively. A total of 977 isolates (775 Enterobacterales isolates, 119 Pseudomonas aeruginosa isolates, and 83 Acinetobacter baumannii complex isolates) were tested. Overall essential agreement (EA) was 96.4% and 96.6% for Enterobacterales when FDA and ISO 20776-2 criteria, respectively, were followed. EA was 98.3% for P. aeruginosa and 91.6% for the A. baumannii complex when both the FDA and ISO criteria were followed. Applying CLSI-FDA breakpoints, categorical agreement (CA) reached 93.0%, 93.3%, and 89.2% for the Enterobacterales, P. aeruginosa, and the A. baumannii complex, respectively. Two very major errors (VMEs; 1.1%) were found among the Enterobacterales (for 2 Klebsiella pneumoniae isolates). No additional major errors (MEs) or VMEs were found. Applying EUCAST breakpoints, CA was 94.8% and 95.8% for Enterobacterales and P. aeruginosa, respectively (no breakpoints are currently available for the A. baumannii complex). No VMEs were observed among the Enterobacterales, but 2 (0.4%) MEs were found. Among the P. aeruginosa isolates, 2 (6.9%) VMEs and 3 (3.3%) MEs were observed. These errors resulted when P/T Etest MICs were 1 doubling dilution apart from the BMD MICs. In conclusion, the new P/T Etest represents an accurate tool for performing antimicrobial susceptibility testing of Enterobacterales, P. aeruginosa, and A. baumannii complex isolates with limited category errors.

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