scholarly journals Effect of antibiotic combinations by break-point checkerboard plate and disk diffusion method against drug-resistant Pseudomonas aeruginosa

2014 ◽  
Vol 63 (1) ◽  
pp. 18-23
Author(s):  
Hiromi MORISHIGE ◽  
Yoshihito OTSUKA ◽  
Akihiro TOGUCHI ◽  
Masako HIRATA ◽  
Kohei HASHIMOTO ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Break Point ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
Drug Resistant ◽  
Disk Diffusion Method

scholarly journals Phenotypic screening of metallo--lactamase in multi-drug-resistant Pseudomonas aeruginosa using a combined disk diffusion method

2013 ◽  
Vol 7 (45) ◽  
pp. 5195-5199 ◽  
Author(s):  
Erfani Yousef ◽  
Fallah Fatemeh ◽  
Sadat Sajadi Nia Raheleh ◽  
Rasti Arezoo ◽  
Heydarian Moghadam Mohammad
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
Phenotypic Screening ◽  
Drug Resistant ◽  
Disk Diffusion Method

Ceftazidime – Avibactam susceptibility among carbapenem-resistant Enterobacterales in a pilot study in Turkey

2021 ◽  
Author(s):  
Hasan Selcuk Ozger ◽  
Ebru Evren ◽  
Serap Suzuk Yildiz ◽  
Cigdem Erol ◽  
Fatma Bayrakdar ◽  
...  
Keyword(s):  
Practical Method ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
Drug Resistant ◽  
Chain Reaction ◽  
Disk Diffusion Method ◽  
Carbapenem Resistant ◽  
Therapeutic Choice ◽  
Polymerase Chain

AbstractThis study aimed to detect carbapenemase genes and to determine the in vitro susceptibility of Ceftazidime-Avibactam (CZA) in Enterobacterales isolates. Carbapenemase genes were detected by polymerase chain reaction. CZA sensitivity of isolates was evaluated with broth microdilution (BMD) and disk diffusion methods. A total of 318 carbapenem-resistant Enterobacterales isolates were included. Most of the isolates (n = 290, 91.2%) were identified as Klebsiella pneumoniae. The most common carbapenemase type was OXA-48 (n = 82, 27.6%). CZA susceptibility was evaluated in 84 isolates with OXA-48 and KPC carbapenemase activity. Both BMD and disk diffusion methods revealed that 95.2% of the isolates were sensitive to CZA; whereas, 4 (4.76%) isolates were resistant to CZA. Among colistin resistant isolates, 96.5% (n = 80) of them were susceptible to CZA. Our study demonstrated high in vitro efficacy of CZA in Enterobacterales isolates producing OXA-48 carbapenemase. High susceptibility rates against colistin resistant isolates which generally are also pan drug resistant, makes CZA a promising therapeutic choice for difficult-to-treat infections. Due to its high correlation with the BMD, disk diffusion method is a suitable and more practical method in detecting CZA in vitro activity.

scholarly journals Comparison of Agar Diffusion Methodologies for Antimicrobial Susceptibility Testing of Pseudomonas aeruginosa Isolates from Cystic Fibrosis Patients

2000 ◽  
Vol 38 (5) ◽  
pp. 1818-1822 ◽  
Author(s):  
Jane L. Burns ◽  
Lisa Saiman ◽  
Susan Whittier ◽  
Davise Larone ◽  
Jay Krzewinski ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Pseudomonas Aeruginosa ◽  
Susceptibility Testing ◽  
Correlation Coefficients ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
Broth Microdilution ◽  
Disk Diffusion Method ◽  
Agar Diffusion ◽  
Broth Microdilution Method

Pseudomonas aeruginosa is the most common pathogen infecting the lungs of patients with cystic fibrosis (CF). Improved antimicrobial chemotherapy has significantly increased the life expectancy of these patients. However, accurate susceptibility testing of P. aeruginosa isolates from CF sputum may be difficult because the organisms are often mucoid and slow growing. This study of 597 CF isolates of P. aeruginosa examined the correlation of disk diffusion and Etest (AB BIODISK, Solna, Sweden) results with a reference broth microdilution method. The rates of interpretive errors for 12 commonly used antipseudomonal antimicrobials were determined. The disk diffusion method correlated well (zone diameter versus MIC) for all of the agents tested. However, for mucoid isolates, correlation coefficients (r values) for piperacillin, piperacillin-tazobactam, and meropenem were <0.80. The Etest correlation with reference broth microdilution results (MIC versus MIC) was acceptable for all of the agents tested, for both mucoid and nonmucoid isolates. Category interpretation errors were similar for the disk diffusion and Etest methods with 0.4 and 0.1%, respectively, very major errors (false susceptibility) and 1.1 and 2.2% major errors (false resistance). Overall, both agar diffusion methods appear to be broadly acceptable for routine clinical use in susceptibility testing of CF isolates of P. aeruginosa.

scholarly journals Evaluation of Etests and the disk diffusion method for assessment of the activity of ceftazidime-avibactam against Enterobacterales and Pseudomonas aeruginosa in China

2020 ◽  
Author(s):  
Qi Wang ◽  
Feifei Zhang ◽  
Zhanwei Wang ◽  
Hongbin Chen ◽  
Xiaojuan Wang ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Random Selection ◽  
Alternative Methods ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
Broth Microdilution ◽  
Antimicrobial Susceptibility Test ◽  
Disk Diffusion Method ◽  
Gram Negative ◽  
Selection Group

Abstract Background: Gram-negative bacilli, particularly Enterobacterales and Pseudomonas aeruginosa, often acquire antimicrobial resistance. Ceftazidime-avibactam was approved for use in China in 2019. However, currently available commercial antimicrobial susceptibility test kits have not yet been developed. Here, we evaluated the Etest and disk diffusion method for assessment of the efficacy of ceftazidime-avibactam against Enterobacterales and P. aeruginosa in China. Results: In total, 194 Enterobacterales and 77 P. aeruginosa isolates, which were divided into a random selection group (140 Enterobacterales and 54 P. aeruginosa isolates) and a stock group (46 Enterobacterales and 31 P. aeruginosa isolates), were assessed by the Etest, disk diffusion, and broth microdilution (BMD) methods. Minimum inhibitory concentrations (MICs) and zone diameters were interpreted according to the CLSI M100 30th edition. For all 271 Enterobacterales and P. aeruginosa isolates, no very major errors were found using Etests. The overall categorical agreement rates (CA%) of Etests for Enterobacterales and P. aeruginosa were 99.5% (193/194) and 96.1% (74/77), respectively. The overall essential agreement rates (EA%) of Etests for Enterobacterales and P. aeruginosa were 95.9% (186/194) and 94.8% (73/77), respectively. In both the random selection and stock groups, EA% and CA% values of Etests exceeded 90%. Overall CA% values of the disk diffusion method for Enterobacterales and P. aeruginosa were 98.5% (191/194) and 93.5% (71/77), respectively. There was no linear relationship between zone diameter and BMD MIC. Conclusions: For Enterobacterales and P. aeruginosa, Etests and the disk diffusion method could have better performance as alternative methods to meet the needs of clinical treatment interpretation. Application of the disk diffusion method in Enterobacterales was superior to that in P. aeruginosa.

scholarly journals Performance Evaluation of the Gradient Diffusion Strip Method and Disk Diffusion Method for Ceftazidime–Avibactam Against Enterobacterales and Pseudomonas aeruginosa: A Dual-Center Study

2021 ◽  
Vol 12 ◽  
Author(s):  
Jingjia Zhang ◽  
Gang Li ◽  
Ge Zhang ◽  
Wei Kang ◽  
Simeng Duan ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Carbapenem Resistance ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
Major Error ◽  
Beta Lactam ◽  
Disk Diffusion Method ◽  
Strip Method ◽  
Gradient Diffusion

Objectives: Ceftazidime–avibactam is a novel synthetic beta-lactam + beta-lactamase inhibitor combination. We evaluated the performance of the gradient diffusion strip method and the disk diffusion method for the determination of ceftazidime–avibactam against Enterobacterales and Pseudomonas aeruginosa.Methods: Antimicrobial susceptibility testing of 302 clinical Enterobacterales and Pseudomonas aeruginosa isolates from two centers were conducted by broth microdilution (BMD), gradient diffusion strip method, and disk diffusion method for ceftazidime–avibactam. Using BMD as a gold standard, essential agreement (EA), categorical agreement (CA), major error (ME), and very major error (VME) were determined according to CLSI guidelines. CA and EA rate &gt; 90%, ME rate &lt; 3%, and VME rate &lt; 1.5% were considered as acceptable criteria. Polymerase chain reaction and Sanger sequencing were performed to determine the carbapenem resistance genes of all 302 isolates.Results: A total of 302 strains were enrolled, among which 182 strains were from center 1 and 120 strains were from center 2. A percentage of 18.21% (55/302) of the enrolled isolates were resistant to ceftazidime–avibactam. The CA rates of the gradient diffusion strip method for Enterobacterales and P. aeruginosa were 100% and 98.65% (73/74), respectively, and the EA rates were 97.37% (222/228) and 98.65% (73/74), respectively. The CA rates of the disk diffusion method for Enterobacterales and P. aeruginosa were 100% and 95.95% (71/74), respectively. No VMEs were found by using the gradient diffusion strip method, while the ME rate was 0.40% (1/247). No MEs were found by using the disk diffusion method, but the VME rate was 5.45% (3/55). Therefore, all the parameters of the gradient diffusion strip method were in line with acceptable criteria. For 31 blaKPC, 33 blaNDM, 7 blaIMP, and 2 blaVIM positive isolates, both CA and EA rates were 100%; no MEs or VMEs were detected by either method. For 15 carbapenemase-non-producing resistant isolates, the CA and EA rates of the gradient diffusion strips method were 100%. Whereas the CA rate of the disk diffusion method was 80.00% (12/15), the VME rate was 20.00% (3/15).Conclusion: The gradient diffusion strip method can meet the needs of clinical microbiological laboratories for testing the susceptibility of ceftazidime–avibactam drugs. However, the VME rate &gt; 1.5% (5.45%) by the disk diffusion method. By comparison, the performance of the gradient diffusion strip method was better than that of the disk diffusion method.

scholarly journals Distribution of Extended-spectrum β-lactamase and Metallo-β-lactamase-producing Pseudomonas aeruginosa in Tertiary Care Hospitals of Lahore, Pakistan

2019 ◽  
Vol 8 (1) ◽  
pp. 23-28 ◽  
Author(s):  
Syeda Aneela ◽  
Noor- Ul-Ain ◽  
Samyyia Abrar ◽  
Muhammad Saeed ◽  
Shahida Hussain ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Tertiary Care ◽  
Multidrug Resistant ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
Military Hospital ◽  
Disk Diffusion Method ◽  
Disk Diffusion Test ◽  
Extended Spectrum ◽  
Synergy Test

Background: Pseudomonas aeruginosa (P. aeruginosa) is an important bacterial pathogen most frequently associated with nosocomial infections, especially in immuno-compromised patients. Early detection of these life threatening, β-lactamase producing bacteria is essential for infection control and to prevent their dissemination. The aim of our study was to detect the presence of Extended-Spectrum β-Lactamase (ESBL) and Metallo-β-Lactamase (MBL) strains of Pseudomonas aeruginosa.Material and Methods: Eighty-eight identified strains of P. aeruginosa were collected from Chughtai Laboratories, Combined Military Hospital and Children Hospital, Lahore. These strains were sub-cultured and after confirming the cultural characteristics by Gram staining and colony morphology, manual biochemical identification was done. Susceptibility to various antibiotics and production of extended-spectrum β-lactamases (ESBLs) and metallo-β-lactamases (MBLs) were determined using modified Kirby Bauer disk diffusion method, double disk synergy test, combined disk synergy test (CDST) and inhibitor-potentiated disk diffusion test (IPD) respectively.Results: Out of eighty-eight strains tested, three were ESBL producers (3.4%) and eleven strains (12.5%) were found to be resistant to carbapenems. Of these, eight were MBL producers (72.7%). All these β-lactamase producing strains (14 strains) were multidrug-resistant (MDR). Piperacillin and piperacillin/tazobactam proved to be the most effective antibiotics in both types of β-lactamase producing strains.Conclusion: Our study shows noticeable emergence of β-lactamases (ESBLs & MBLs) in P. aeruginosa. All of these strains were MDR. It reveals a correlation of these β-lactamases with multidrug resistant genes.

scholarly journals Comparison of two disk diffusion and E-test methods in determining antibiotic susceptibility of Pseudomonas aeruginosa strains in isolated burn infections of Ahvaz City

2020 ◽  
Vol 19 (4) ◽  
pp. 646-651
Author(s):  
Changiz Ahmadizadeh ◽  
Mehrdad Pashazadeh
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Medical Science ◽  
Opportunistic Pathogen ◽  
Test Methods ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
Burn Patients ◽  
Human Beings ◽  
Disk Diffusion Method ◽  
Biochemical Identification

Background: Pseudomonas aeruginosa with widely distributed in nature, for human beings is considered an opportunistic pathogen that causes infections of broad-spectrum, including administrative, respiratory, septicemia and bacteremia and sepsis in patients with the burning city of Ahvaz. Method and Material: A total of 95isolates of Pseudomonas aeruginosa isolated from burn patients from January 2015 assemble and biochemical identification test, then they are antibiotic resistance in E. test and disk diffusion method were compared. Findings: From 95 different clinical isolates of Pseudomonas aeruginosa isolated from E. test with the highest sensitivity to the antibiotic ceftazidime , 70(68/73%) and ciprofloxacin 50 (63/52%) and gentamicin 48 (52 /50 %) and the antibiotic imipenem 44 (31/46%) were sensitive and disk diffusion method antibiotic ceftazidime, 67(52/70%) and the antibiotic Ciprofloxacin 51(68/53%) and safety antibiotic imipenem 49(57/51%) and gentamicin 48(52/50%) were sensitive. Conclusion: Statistically significant differences between E. test and disk diffusion antimicrobial susceptibility of there (p<0.05) and disk diffusion method can replace E. test, and also the most sensitive antibiotics, the antibiotics used The study of the isolated Pseudomonas is ceftazidime. Bangladesh Journal of Medical Science Vol.19(4) 2020 p.646-651

Molecular Characterization of Tigecycline Non-Susceptibility among Extensively Drug-Resistant Acinetobacter baumannii Isolates of Clinical Origin

Chemotherapy ◽  
2021 ◽  
pp. 1-7
Author(s):  
Mehri Haeili ◽  
Ali Abdollahi ◽  
Amin Ahmadi ◽  
Amin Khoshbayan
Keyword(s):  
Acinetobacter Baumannii ◽  
Molecular Mechanisms ◽  
Efflux Pump ◽  
Genetic Alterations ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
Transcriptional Level ◽  
Drug Resistant ◽  
Disk Diffusion Method ◽  
Extensively Drug Resistant

<b><i>Introduction:</i></b> Tigecycline (TGC) is one of the last-resort therapeutic agents for treating infections caused by extensively drug resistant <i>Acinetobacter baumannii</i> isolates. Although resistance to TGC is not common, non-susceptible <i>A. baumannii</i> (NSAB) isolates have been described. In the current study, we aimed to assess the molecular mechanisms mediating TGC non-susceptibility in 5 clinical isolates of <i>A. baumannii</i> with reduced susceptibility to TGC. <b><i>Methods:</i></b> Susceptibility of isolates to TGC as well as various classes of antibiotics was evaluated by broth dilution and disk diffusion methods, respectively. The presence of <i>tetX</i> and <i>tetX1</i> genes was investigated by PCR. The nucleotide sequences of <i>adeR</i> and <i>adeS</i> genes were assessed by PCR amplicon sequencing. To evaluate the association between reduced susceptibility to TGC and upregulation of AdeABC efflux pump, transcriptional level of <i>adeB</i> gene was quantified by RT-qPCR analysis. <b><i>Results:</i></b> All 5 TGC-NSAB isolates had a TGC MIC of ≥4 mg/L and were resistant to all antimicrobials tested by disk diffusion method except for minocycline and doxycycline for which a susceptibility rate of 40% and 20% was observed, respectively. The <i>tetX/X1</i> genes were not detected in any isolates. All TGC non-susceptible isolates harbored genetic alterations in the <i>adeRS</i> operon, including AdeS G186V, N268H, and D60N and AdeR A136V and V120I substitutions among, which G186V and D60N were predicted by PROVEAN tool analysis as inactivating alterations. Reduced TGC susceptibility was associated with upregulation of AdeABC efflux pump in all TGC non-susceptible isolates. <b><i>Conclusion:</i></b> It can be concluded from our results that reduced susceptibility to TGC in the studied isolates was mainly mediated by genetic alterations in the AdeRS system, which resulted in overexpression of AdeABC efflux pump. Emergence of TGC non-susceptibility among isolates that had not been previously exposed to TGC is an issue of great concern.

Antibacterial Activity of Different Concentrations of Date Vinegar in Comparison to Ciprofloxacin against Multidrug-Resistance Pseudomonas aeruginosa Isolated from Infected Burn

2018 ◽  
Vol 16 (2) ◽  
pp. 96-99
Author(s):  
Ihsan S. Rabeea ◽  
Ali M.H. Janabi
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Treatment Strategies ◽  
Inhibition Zone ◽  
Current Treatment ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
Disk Diffusion Method ◽  
Local Toxicity ◽  
Agar Dilution

Background: Despite recent advances in burns management and antimicrobial chemotherapy, infection continues to be a tricky in the burns. Treatment of a burn infection especially in case of multi-drug resistant Pseudomonas aeruginosa is a big challenge in clinics and needs novel strategies. Miscarriage of the current treatment strategies to control several cases of burns infections, the systemic and local toxicity that are produced by many topical antibiotics (especially in children), and the delay of healing caused by several antiseptics, make a strong motive to find effective and safe products. Aim: This study aimed to investigate the in vitro activity of different concentration of date vinegar against P. aeruginosa in comparison to the ciprofloxacin, one of the antibiotics used in the treatment of burns infection by using disk diffusion method and agar dilution MICs assay. Results and Conclusion: The disk diffusion method revealed that mean inhibition zone of date vinegar at 100%, 50%, 20%, 10% and 5% were (50.9 ±0.27) mm, (30.5 ±0.24) mm, (25.9 ±0.29) mm, (18.3±0.22) mm, and (9.2±0.25) mm respectively while ciprofloxacin has mean inhibition zone (8.95 ±2.25) mm and MICs (1.25%). So the conclusion was that date vinegar exerted a good in vitro antimicrobial activity against all tested isolates.

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