scholarly journals Comparison of Colistin MIC by Microbroth Dilution, E-Test and Vitek-2, in Isolates of Acinetobacter spp. Isolated from Bloodstream Infections

2021 ◽  
Vol 8 (12) ◽  
pp. 218-233
Author(s):  
Nazir Ahmad Var ◽  
Nisar Ahmad Wani ◽  
Syed Khurshid Ahmad
Keyword(s):  
Antimicrobial Resistance ◽  
Reference Method ◽  
Bloodstream Infections ◽  
Test Methods ◽  
Hospital Environment ◽  
Dilution Method ◽  
Acinetobacter Species ◽  
Antibiotic Susceptibility Test ◽  
Testing Susceptibility ◽  
Vitek 2

Background: Acinetobacter species are leading cause of nosocomial infections, causing significant morbidity and mortality globally including India. Being persistent in the hospital environment and rapidly developing resistance to a wide variety of antibiotics are the most important features of this pathogen. The present study aimed to compare Colistin MIC of Acinetobacter species isolated from the blood samples by E test and Vitek 2 to the standard broth micro dilution test. Methodology: Two antibiotic susceptibility test methods, The Vitek-2 and the E test, against the reference broth micro dilution method in terms of the various parameters such as Reproducibility, reliability, cost and time effectiveness. Data obtained from the current study regarding antimicrobial resistance of Acinetobacter species recovered from clinical specimens referred to microbiology laboratory of SKIMS and was analyzed by using SPSS20.0. Results: Out of 100 isolates of Acinetobacter species analyzed from blood specimens the distribution of Acinetobacter species according to different clinical diagnosis of patients 89% were A. baumannii and 11% were A. lwoffii. Seventy three percent of them were from males and 27% of them were from females with a mean age of 39.6 (SD±27.46). Regarding the specimen and isolate sources, the majority were from ICU (54%), Surgical ward (26%), Medical ward (16%) and 4% from Outpatient department of SKIMS. Significant descending trends of antimicrobial resistance was shown for Amoxicillin/Clavulanic acid, Cefoperazone/ Sulbactam combination, Cotrimoxazole (100%), Levofloxacin (92%) Piperacillin/Tazobactam, Ciprofloxacin (90%), Cephalosporins (>80%), Imipenem and Meropenem (76%), Amikacin (68%), Gentamycin (67%), Tigecycline (11%) and 0% for Colistin respectively. Conclusion: from the study it could be concluded that the best reference method for testing susceptibility to the Polymyxins still remains to be defined. However, in routine clinical practice in most regions worldwide, where a reference method can hardly be implemented, the interpretation of Colistin susceptibility should preferably be based on results of automated systems such as Vitek-2 or the E test. The micro broth Dilution method remains the most reliable and reproducible, however most tedious and time-consuming method. Colistin remains a very effective, least resisted drug for MDR Acinetobacter species as compared by all the three methods. Keywords: Acinetobacter species; Antimicrobial resistance; Colistin; E test and Vitek 2.

Antibiotic Resistance of Salmonella Isolated from Hog, Beef, and Chicken Carcass Samples from Provincially Inspected Abattoirs in Ontario

2004 ◽  
Vol 67 (3) ◽  
pp. 448-455 ◽  
Author(s):  
C. LARKIN ◽  
C. POPPE ◽  
B. MCNAB ◽  
B. MCEWEN ◽  
A. MAHDI ◽  
...  
Keyword(s):  
Antimicrobial Resistance ◽  
The United States ◽  
Test Methods ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Chicken Carcass ◽  
Resistance Patterns ◽  
Agar Dilution ◽  
Microbroth Dilution ◽  
Good Agreement

The emergence of antimicrobial-resistant Salmonella organisms, especially Salmonella Typhimurium DT104, has been reported in many countries, including the United States and Canada. The purposes of this study were to determine the antimicrobial resistance patterns of Salmonella isolated from hog, beef, and chicken carcasses from provincially inspected abattoirs in Ontario and to determine the agreement between the agar dilution method and the microbroth dilution method for measurement of antimicrobial resistance of the isolates. Antimicrobial resistance of Salmonella isolates from hogs (n = 71), beef (n = 24), and chicken (n = 295) to amikacin, ampicillin, cephalothin, chloramphenicol, ciprofloxacin, gentamicin, streptomycin, sulfamethoxazole,and tetracycline was determined using the two methods. None of the 390 isolates were resistant to ciprofloxacin at levels of 0.125 μg/ml. All chicken and hog isolates were sensitive to amikacin, whereas all beef isolates were sensitive to both amikacin and gentamicin. Multiple antimicrobial resistance (resistance to more than one antimicrobial) was found in 29% of bovine isolates and 42% of porcine isolates using both methods for testing and in 42% by the agar dilution and 33% by the microbroth dilution methods in the chicken isolates. Overall, there was good agreement between the two test methods for resistance to most of the antimicrobials, with disagreement found in the results in 1.3% of the isolates for ampicillin and sulfamethoxazole, 8.2% for streptomycin, 5.6% for cephalothin, and 1.0% of the isolates for tetracycline. The lack of agreement between the two test methods was found mostly among the chicken isolates.

scholarly journals Comparison of Automated and Manual Methods for Antimicrobial Susceptibility Testing

2020 ◽  
pp. 43-48
Author(s):  
Asifa Bhat ◽  
Dekyong Angmo ◽  
Shaista Nazir
Keyword(s):  
Klebsiella Pneumoniae ◽  
Antimicrobial Susceptibility ◽  
Error Rate ◽  
Antimicrobial Agents ◽  
Reference Method ◽  
Multidrug Resistant ◽  
Dilution Method ◽  
Automated Method ◽  
Broth Microdilution Method ◽  
Vitek 2

Background: Carbapenems are considered the broadest-spectrum β-lactam agents and are often required for treatment of severe hospital-acquired infections caused by multidrug-resistant Gram-negative organisms. Minimum inhibitory concentrations (MICs) are important in diagnostic laboratories to confirm resistance of microorganisms to an antimicrobial agent and also to monitor the activity of new antimicrobial agents. Aims and Objectives: To compare the MIC obtained by Broth Microdilution method (BMD) with that of Vitek-2(automated method) for recovered isolates of Klebsiella pneumoniae. Materials and Methods: Prospective study conducted over a period of one year. It included all isolates of Klebsiella pneumoniae recovered from blood culture of the patients. The identification and antimicrobial susceptibility was done on Vitek-2.These Isolates were subjected to Microbroth dilution method for MIC determination. Results: Out of the 55 meropenem resistant  isolates by vitek-2, 20(36.3%) had MIC of ≥256 µg/ml followed by 18(32.7%) isolates with a MIC of 128 µg/ml, followed by 11(20%) isolates with MIC of 64 µg/ml and 6(10.9%) isolates with MIC of 32 µg/ml. Also among 15 meropenem sensitive isolates by Vitek-2, 13(86.7%) had MIC of ≤0.5 µg/ml, followed by two (13.3%) isolates with MIC of 2 µg/ml. Results obtained by vitek 2 were compared with those from BMD(the reference method), which showed a 13.3% minor error rate and no major or very major error rate. Conclusion: Overall, the Vitek 2 performance was comparable to that of BMD for testing a limited number of Klebsiella pneumoniae isolates.

scholarly journals Comparison of different methods of determining β-lactam susceptibility in clinical strains of Pseudomonas aeruginosa

2009 ◽  
Vol 58 (5) ◽  
pp. 625-629 ◽  
Author(s):  
Eva Torres ◽  
Rosa Villanueva ◽  
Germán Bou
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Reference Method ◽  
Test System ◽  
Testing Susceptibility ◽  
Vitek 2 ◽  
High Level ◽  
Resistance Rates ◽  
Susceptibility And Resistance ◽  
Good Agreement

One hundred and one randomly selected (2003–2005) clinical isolates of Pseudomonas aeruginosa were used to assess the quantitative (MIC) and qualitative (susceptibility category) agreement between the microdilution broth reference method (RM) and disc diffusion (DD), Etest and the VITEK 2 automated susceptibility test system for determination of the susceptibility of P. aeruginosa to piperacillin (PIP), PIP–tazobactam (TZP), ceftazidime (CAZ), aztreonam (ATM) cefepime (FEP) and imipenem (IMP). The results obtained by the RM were compared with those obtained by the other methods. The RM and DD were performed according to CLSI criteria. Etest and VITEK 2 were according to the manufacturer's instructions. The Advanced Expert System (AES), which interprets MICs generated by VITEK 2, was modified with new rules of interpretation. Overall, VITEK 2 showed the lowest MIC90 values for the six antibiotics. The RM categorical testing (susceptibility and resistance) rates with P. aeruginosa were 11.8 and 88.1 for PIP, 22.7 and 77.2 for TZP, 14.8 and 78.2 for CAZ, 12.8 and 54.4 for ATM, 16.8 and 75.3 for FEP, and 7.9 and 90.1 for IMP, respectively. Very major errors (false susceptible) were only detected for ATM and FEP with DD and for IMP with three methods. Major errors (false resistant) were generally acceptable for all antibiotics except TZP. VITEK 2 yielded a high level of minor errors (trends toward false susceptibility), mainly with CAZ and FEP. A good agreement was obtained for all antibiotics/methods assayed, thus highlighting the importance of the AES for categorization of β-lactam susceptibility in P. aeruginosa.

scholarly journals Comparative evaluation of six phenotypic methods for detecting extended-spectrum beta-lactamase-producing Enterobacteriaceae

2014 ◽  
Vol 8 (04) ◽  
pp. 408-415 ◽  
Author(s):  
Rajkumar Manojkumar Singh ◽  
Huidrom Lokhendro Singh
Keyword(s):  
Sensitivity And Specificity ◽  
Reference Method ◽  
Clinical Isolates ◽  
Dilution Method ◽  
Beta Lactamase ◽  
Extended Spectrum Beta Lactamase ◽  
Extended Spectrum ◽  
Vitek 2 ◽  
Phenotypic Methods ◽  
Disk Test

Introduction: Various conventional phenotypic methods and automated systems have been evaluated for extended-spectrum beta-lactamase (ESBL) detection. There is a paucity of data comparing these methods using the same clinical isolates in eastern and north-eastern parts of India. The present study was designed to compare the capacity of six phenotypic methods to detect ESBLs in clinical isolates of Enterobacteriaceae. Methodology: A total of 206 non-duplicate clini­cal isolates of Enterobacteriaceae, obtained over a period of six months (July to December, 2012), were tested by the Vitek 2, double disk synergy tests (30 mm, 20 mm, and modified method), combined disk test, and ESBL Etest to evaluate their ability to detect ESBLs. Minimal inhibitory concentration (MIC) by the agar dilution method was used as the reference method. Result: The reference method detected ESBLs in 57 (27.7%) isolates. Among the six methods, the combined disk test demonstrated an overall agreement of 100% with the MIC. The Vitek 2 showed a sensitivity and specificity of 91.8% and 97.24%, respectively, with a positive predictive value of 93.33%. The sensitivities of the conventional methods ranged from 83% to 94%. The highest sensitivity and specificity were shown by combined disk (93.44%) and double disk synergy (100%) techniques, respectively. Conclusion: In our setting, Vitek 2 showed an acceptable capacity to detect ESBL isolates as it improved the turnover time (6 to 8 hours) in comparison to conventional phenotypic methods, which took a minimum of 24 hours. However, the combined disk test achieved the highest sensitivity.  

scholarly journals Australian Group on Antimicrobial Resistance (AGAR) Australian Gram-negative Sepsis Outcome Programme (GNSOP) Annual Report 2018

2020 ◽  
Vol 44 ◽  
Author(s):  
Jan M Bell ◽  
Thomas Gottlieb ◽  
Denise A Daley ◽  
Geoffrey W Coombs
Keyword(s):  
Antimicrobial Resistance ◽  
Bloodstream Infections ◽  
Generation Cephalosporin ◽  
Acinetobacter Species ◽  
Gram Negative ◽  
Prevalence Studies ◽  
E Coli ◽  
Carbapenemase Gene ◽  
Resistance Rates ◽  
Outcome Programme

The Australian Group on Antimicrobial Resistance (AGAR) performs regular period-prevalence studies to monitor changes in antimicrobial resistance in selected enteric gram-negative pathogens. The 2018 survey was the sixth year to focus on bloodstream infections, and included Enterobacterales, Pseudomonas aeruginosa and Acinetobacter species. Eight thousand three hundred and fifty isolates, comprising Enterobacterales (7,512, 90.0%), P. aeruginosa (743, 8.9%) and Acinetobacter species (95, 1.1%), were tested using commercial automated methods. The results were analysed using Clinical and Laboratory Standards Institute (CLSI) and European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoints (January 2019). Of the key resistances, resistance to the third-generation cephalosporin, ceftriaxone, was found in 13.4%/13.4% of Escherichia coli (CLSI/EUCAST criteria), and 9.4%/9.4% of Klebsiella pneumoniae. Resistance rates to ciprofloxacin were 15.2%/15.2% for E. coli, 11.3%/11.3% for K. pneumoniae, 7.4%/7.4% for Enterobacter cloacae complex, and 3.6%/7.7% for P. aeruginosa. Resistance rates to piperacillin-tazobactam were 3.0%/6.0%, 4.3%/7.9%, 18.2%/22.0%, and 5.1%/11.1% for the same five species respectively. Thirty-one isolates from 27 patients were shown to harbour a carbapenemase gene: 14 blaIMP-4 (11 patients), including one with blaIMP-4+blaOXA-23, four blaKPC (three patients), three blaOXA-48, three blaNDM, three blaGES. two blaOXA-181, and two blaOXA-23.

scholarly journals Impact of Efflux Pump Inhibitor Carbonyl-Cyanide M-Chlorophenylhydrazone in Multidrug Resistant AcinetobacterSpecies Isolates from Sterile Body Fluids

2020 ◽  
Author(s):  
Shahid Raza ◽  
Hitender Gautam ◽  
Bhavna Maheshwari ◽  
Sarita Mohapatra ◽  
Seema Sood ◽  
...  
Keyword(s):  
Antimicrobial Resistance ◽  
Antimicrobial Susceptibility ◽  
Efflux Pump ◽  
Body Fluids ◽  
Efflux Pump Inhibitor ◽  
Acinetobacter Species ◽  
Acinetobacter Junii ◽  
Carbonyl Cyanide ◽  
Vitek 2 ◽  
Sterile Body Fluids

Introduction: Antimicrobial resistance of Acinetobacter baumannii(A. baumannii) are rapidly emerging, becoming non-responsive to most of the commonly prescribed antibiotics and leaving us with few treatment options and galloping treatment costs. Aim: To study the effect of Efflux Pump Inhibitor (EPI) Carbonyl Cyanide 3-Chlorophenylhydrazone (CCCP) on Multidrug Resistance (MDR) A. baumannii isolates from different sterile body fluids. Materials and Methods: A total of 40 Acinetobacter species isolates from different sterile body fluids i.e., Cerebrospinal Fluid (CSF), ascitic fluid, pleural fluid, and peritoneal fluid were collected and identified by Matrix Assisted Laser Desorption/Ionisation-Time Of Flight (MALDI-TOF), Biomerieux, France. Minimum Inhibitory Concentration (MIC) of A. baumannii was determined by automated VITEK-2 Antimicrobial Susceptibility Testing (AST) system (Biomerieux, France). In addition, MIC of the isolates, grown on Mueller-Hinton Agar (MHA) plate with 15 μg/mL with EPI CCCP (Sigma Aldrich, US) was determined. For Tigecycline, MIC was determined by Broth Microdilution (BMD) method. Results: Out of 40 isolates, 34 (85%) were A. baumannii and 6 (15%) were Acinetobacter junii. Most of the Acinetobacter spps were MDR and only susceptible to few antibiotics. Most effective antibiotic was Tigecycline 25 (73.52%) followed by Co-trimoxazole 10 (29.41%). Similarly, Out of 40 isolates, 2 to 64 folds reductions in MIC was observed due to CCCP in 10 (25%) isolates for various antibiotics. Likewise, for Tigecycline, 2 to 4 folds reductions in MIC value (One strain changed from intermediate to sensitive) was observed by VITEK-2 AST which corroborated with reduction in MIC by BMD after addition of CCCP. Conclusion: MDR A. baumannii are spreading rapidly. There is the need to overcome the antimicrobial resistance by investigating resistance inhibiting substance that will help to restore antimicrobial susceptibility and bringing back the existing antibiotics in prescription.

Fluoroquinolone E-Testing against Pseudomonas Aeruginosa and Streptococcus Pneumoniae

2002 ◽  
Vol 18 (5) ◽  
pp. 241-247
Author(s):  
Eric G Sahloff ◽  
Benjamin P Smith ◽  
Steven J Martin
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Streptococcus Pneumoniae ◽  
Clinical Laboratory ◽  
Reference Method ◽  
Test Methods ◽  
National Committee ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Drug Activity ◽  
Agar Dilution

Objectives and Design: The use of fluoroquinolones has increased against antibiotic-resistant pathogens such as Streptococcus pneumoniae and Pseudomonas aeruginosa. The E-test (AB Biodisk, Solna, Sweden) is now commonly used for susceptibility testing of fluoroquinolones against these organisms. The purpose of the present study was to evaluate the accuracy and correlation of minimum inhibitory concentrations (MICs) determined by E-testing with a National Committee for Clinical Laboratory Standards reference standard, agar-dilution MIC testing. E-test and agar dilution MICs were compared for ciprofloxacin, levofloxacin, gatifloxacin, and moxifloxacin against clinical isolates of S. pneumoniae (n = 53) and P. aeruginosa (n = 62). Main Outcome Measures: MICs were determined by use of agar dilution and E-test methods. Essential agreement was defined as MICs from both methods within ± 1 log2 dilution. Categorical agreement compared MIC interpretations: susceptible, intermediate, or resistant. Categorical disagreement between methods was reported as very major, major, or minor errors. Results: E-tests produced lower MICs than the reference method for ciprofloxacin, gatifloxacin, and moxifloxacin versus P. aeruginosa. For S. pneumoniae, E-test MICs tended to be higher for all fluoroquinolones. The best correlation between testing methods was seen with levofloxacin. Essential agreement occurred more frequently with P. aeruginosa in the lower range of MICs and with S. pneumoniae in the higher range of MICs. Categorical agreement was greater than 90% for the 460 comparisons. Two very major errors (false-susceptible) occurred for gatifloxacin versus P. aeruginosa. Conclusions: For the determination of fluoroquinolone susceptibility against S. pneumoniae and P. aeruginosa, E-testing is a simple tool for clinical use, and few very major or major errors in susceptibility interpretation occur for either organism. For determining fluoroquinolone MICs, E-testing may overestimate drug activity against P. aeruginosa and underestimate drug activity versus S. pneumoniae compared with the agar dilution method. These differences could affect appropriate antimicrobial selection, leading to suboptimal outcomes.

scholarly journals Multidrug resistance pattern of Acinetobacter species isolated from clinical specimens referred to the Ethiopian Public Health Institute: 2014 to 2018 trend anaylsis

PLoS ONE ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. e0250896
Author(s):  
Zeleke Ayenew ◽  
Eyasu Tigabu ◽  
Elias Syoum ◽  
Semira Ebrahim ◽  
Dawit Assefa ◽  
...  
Keyword(s):  
Health Care ◽  
Multidrug Resistance ◽  
Antimicrobial Resistance ◽  
Health Care Facilities ◽  
Hospital Environment ◽  
Infection Prevention And Control ◽  
Time Range ◽  
Reference Laboratory ◽  
Acinetobacter Species ◽  
Clinical Specimens

Background Acinetobacter species have been a leading cause of nosocomial infections, causing significant morbidity and mortality over the entire world including Ethiopia. The most important features of A. baumannii are its ability to persist in the hospital environment and rapidly develop resistance to a wide variety of antibiotics. This study aimed to determine trend of antimicrobial resistance in Acinetobacter species over a five years period. Method A retrospective data regarding occurrence and antimicrobial resistance of Acinetobacter species recovered from clinical specimens referred to the national reference laboratory was extracted from microbiology laboratory data source covering a time range from 2014 to 2018. Socio-demographic characteristics and laboratory record data was analyzed using SPSS 20. Results A total of 102 strains of Acinetobacter species were analyzed from various clinical specimens. Majority of them were from pus (33.3%) followed by blood (23.5%), urine (15.6%) and body fluid (11.7%). Significant ascending trends of antimicrobial resistance was shown for meropenem (12.5% to 60.7%), ceftazidime (82.1% to 100%), ciprofloxacin (59.4% to 74.4%), ceftriaxone (87.1% to 98.6%), cefepime (80.0% to 93.3%) and pipracillin- tazobactam (67.8% to 96.3%). However, there was descending trend of antimicrobial resistance for tobramycin (56.5% to 42.8%), amikacin (42.1% to 31.4%) and trimethoprim-sulfamethoxazole (79.0 to 68.2%). The overall rate of carbapenem non-susceptible and multidrug resistance rates in Acinetobacter species were 56.7% and 71.6%.respectively. Conclusion A five year antimicrobial resistance trend analysis of Acinetobacter species showed increasing MDR and resistance to high potent antimicrobial agents posing therapeutic challenge in our Hospitals and health care settings. Continuous surveillance and appropriate infection prevention and control strategies need to be strengthened to circumvent the spread of multidrug resistant pathogens in health care facilities.

scholarly journals Predictors of mortality in acute pancreatitis complicated with multidrug-resistant Klebsiella pneumoniae infection

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Di Wu ◽  
Junjie Ding ◽  
Yan Jia ◽  
Huanmiao Liu ◽  
Jie Xiao ◽  
...  
Keyword(s):  
Septic Shock ◽  
Drug Resistance ◽  
Acute Pancreatitis ◽  
Klebsiella Pneumoniae ◽  
Bloodstream Infections ◽  
Multidrug Resistant ◽  
Dilution Method ◽  
Predictors Of Mortality ◽  
Antibiotic Susceptibility Test ◽  
Resistance Rates

Abstract Background Multidrug-resistant (MDR) Klebsiella pneumoniae infections, from pancreatic infections to bloodstream infections, influence the mortality of patients with acute pancreatitis (AP) on the condition of limited antibiotic choices. The aim of this study was to investigate the predictor of mortality among AP patients complicated with MDR-K. pneumoniae infections. Methods Seventy-one AP patients who occurred MDR-K. pneumoniae infections from August 1st, 2016 to August 1st, 2020 were enrolled. MDR-K. pneumoniae was defined as the K. pneumoniae strain non-susceptible to at least one agent in three or more antimicrobial categories. MDR-K. pneumoniae isolates were confirmed by Vitek-2 system. Antibiotic susceptibility test was carried out using a micro broth dilution method. Clinical characteristics and drug-resistance rates were retrospectively reviewed, and the predictors of mortality were evaluated by univariate and multivariate analyses. Results The mortality rate of AP patients complicated with MDR-K. pneumoniae infections reached 46.5% (33 of 71), and pancreas (n = 53) was the most common site of MDR-K pneumoniae strains. The drug resistance rates of MDR-K. pneumoniae were high to 11 of 12 common antibiotics (more than 50.0%) except of tigecycline (23.9%). The predictor independently associated with mortality was septic shock (hazard ratio 2.959, 95% confidence intervals 1.396 – 6.272, P = 0.005). Conclusions More attention should be paid for pancreatic MDR-K. pneumoniae infections among AP patients The predictor for mortality of AP patients complicated with MDR-K. pneumoniae infection is septic shock. Therefore, further clinical investigations should focus on areas against septic shock.

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