scholarly journals Comparative analysis of disk diffusion and liquid medium microdillution methods for testing the antibiotic susceptibility patterns of anaerobic bacterial strains isolated from intra-abdominal infections

2011 ◽  
Vol 1 (6) ◽  
pp. 209-220 ◽  
Keyword(s):  
Antibiotic Susceptibility ◽  
Bacterial Resistance ◽  
Empiric Therapy ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
Dilution Method ◽  
Bacterial Strains ◽  
Disk Diffusion Method ◽  
Broth Microdilution Method ◽  
Abdominal Infections

The antibiotic resistance aspects concerning the bacterial strains isolated from intra-abdominal infections signify at present a major problem of therapy. The empiric pre-operatory antimicrobial therapy plays a key role in the management and course of the intra-abdominal infections, an inappropriate therapy resulting in a poor outcome of the clinical cases and an increase of bacterial resistance. The purpose of the present paper was to compare the results of the antibiotic susceptibility of some selected anaerobic strains to certain antibiotics used in the empiric therapy of intra-abdominal infections, achieved by two different methods, in order to select for the current practice the most reliable, simple and rapid one. We have found a good correlation between the results obtained by the standard, Brucella broth microdilution method recommended by CLSI and the disk diffusion method (recommended by Bailey and Scott, 2002), for all tested antibiotics, demonstrating the possibility to use this last simplified method as an alternative to the laborious and time-consuming dilution method, for the routine testing of the antibiotic susceptibility of anaerobic stranis isolated in severe infections.

scholarly journals Antibiotic Susceptibility Profile of Clostridium Difficile Bacteria Isolated from Older Residents of a Nursing Home in Iran

Salmand ◽  
2021 ◽  
Vol 15 (4) ◽  
pp. 496-505
Author(s):  
Ahmad Ghasemi ◽  
◽  
Ashraf Mohabati Mobarez ◽  
Ehsan Mostafavi ◽  
◽  
...  
Keyword(s):  
Nursing Home ◽  
Clostridium Difficile ◽  
Antibiotic Susceptibility ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Disk Diffusion Method ◽  
Nosocomial Diarrhea ◽  
Agar Dilution

Objectives: Clostridium difficile (C. diff) is a gram-positive anaerobic bacterium knwon as the most common cause of nosocomial diarrhea in nursing homes. The antibiotic susceptibility profile is the basic way for successful treatment due to antimicrobial resistance. This present study aims to assess the antibiotic susceptibility profile of C. diff isolated from older residents of a nursing home in Tehran, Iran. Methods & Materials: Forty-two isolates of C. diff were used in this study collected from 289 residents of Kahrizak Nursing Home. Antibiotic susceptibility testing was conducted by using disk-diffusion method, agar dilution method, and Epsilometer test (E-test). Results: All C. diff strains were susceptible to Metronidazole, Vancomycin, Rifampicin, Linezolid and Tigecycline. By using the disk-diffusion method, the highest rate of resistance was related to Clindamycin (100%), Levofloxacin (96.2%), Imipenem (81%), Azithromycin (61%) and Erythromycin (54.8%). All C. diff strains were susceptible to Metronidazole under E-test. Furthermore, 100% and 59.5% of strains were susceptible to Vancomycin and Erythromycin, respectively under agar dilution test. Conclusion: C. diff strains are sensitive to Vancomycin and Metronidazole. These two antibiotics can be used to treat C. diff infections in older adults. The disk diffusion method can be used as a screening test to determine antibiotic resistance.

scholarly journals Bacteriologic Profile and Antibiogram of Blood Culture Isolates in a Pediatric Care Unit

2010 ◽  
Vol 2 (02) ◽  
pp. 085-088 ◽  
Author(s):  
Kavitha Prabhu ◽  
Sevitha Bhat ◽  
Sunil Rao
Keyword(s):  
Blood Culture ◽  
Antibiotic Susceptibility ◽  
Disk Diffusion ◽  
Pediatric Care ◽  
Diffusion Method ◽  
Bacterial Strains ◽  
Biochemical Tests ◽  
Disk Diffusion Method ◽  
Gram Negative ◽  
Screening And Surveillance

ABSTRACT Background / Aims: Septicemia is one of the important causes of mortality and morbidity in neonates and children. Blood culture is the gold standard for the diagnosis. Emergence of multidrug resistant bacterial strains is a major problem in the management of sepsis. Present study was undertaken to identify the common bacterial pathogens associated with pediatric sepsis and to determine their antibiotic susceptibility pattern. Materials and Methods: Blood cultures from 185 suspected cases of sepsis were examined. The growths from the subcultures were identified by conventional biochemical tests. Antibiotic susceptibility testing was performed by modified Kirby-Bauer disk diffusion method and drug resistant strains in primary screening were further processed for extended spectrum beta lactamases (ESBL) and methicillin resistant Staphylococcus aureus (MRSA) status by combination disk method (ESBL) and oxacillin disk diffusion method (MRSA). Results: Out of the 185 cultures obtained from suspected cases, 81 (44%) were culture positive. Fifty-two (35%) of the culture isolates were Gram negative bacilli. Twenty-eight (64%) of the isolates were Gram positive cocci. One case was of mixed infection. The prevalence of MRSA in 41 strains of S. aureus was found to be 29% (12 strains). The overall prevalence of ESBL producers among 28 Gram negative bacterial isolates was found to be 32% (9 strains). Conclusion: This study stresses the need for the continuous screening and surveillance for antibiotic resistance in pediatric care unit.

scholarly journals Screening commercial teat disinfectants against bacteria isolated from bovine milk using disk diffusion

2019 ◽  
Vol 12 (5) ◽  
pp. 629-637 ◽  
Author(s):  
Sarah Rose Fitzpatrick ◽  
Mary Garvey ◽  
Kieran Jordan ◽  
Jim Flynn ◽  
Bernadette O'Brien ◽  
...  
Keyword(s):  
Bacterial Species ◽  
Screening Method ◽  
Bovine Milk ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
Bacterial Strains ◽  
Disk Diffusion Method ◽  
Associated Bacteria ◽  
Bacterial Inhibition ◽  
Milk Samples

Background and Aim: Teat disinfection is an important tool in reducing the incidence of bovine mastitis. Identifying the potential mastitis-causing bacterial species in milk can be the first step in choosing the correct teat disinfectant product. The objective of this study was to screen commercial teat disinfectants for inhibition against mastitis-associated bacteria isolated from various types of milk samples. Materials and Methods: Twelve commercially available teat disinfectant products were tested, against 12 mastitis-associated bacteria strains isolated from bulk tank milk samples and bacterial strains isolated from clinical (n=2) and subclinical (n=3) quarter foremilk samples using the disk diffusion method. Results: There was a significant variation (7-30 mm) in bacterial inhibition between teat disinfection products, with products containing a lactic acid combination (with chlorhexidine or salicylic acid) resulting in the greatest levels of bacterial inhibition against all tested bacteria (p<0.05). Conclusion: In this study, combined ingredients in teat disinfection products had greater levels of bacterial inhibition than when the ingredients were used individually. The disk diffusion assay is a suitable screening method to effectively differentiate the bacterial inhibition of different teat disinfectant products.

scholarly journals Comparison of methods for the determination of antimicrobial resistance in Campylobacter spp. human and the food chain isolates

2008 ◽  
Vol 52 (No. 4) ◽  
pp. 169-174
Author(s):  
M. Holasova ◽  
R. Karpiskova ◽  
S. Karpiskova ◽  
V. Babak ◽  
J. Schlegelova
Keyword(s):  
Nalidixic Acid ◽  
Antimicrobial Agents ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Disk Diffusion Method ◽  
Microdilution Method ◽  
Study Results ◽  
Agar Dilution

With a microdilution method, using the commercial diagnostic test Sensititre Susceptibility Plates for Campylobacter MIC (Trek Diagnostic Systems, Cleveland, OH, USA), disk diffusion and agar dilution method, resistance to six antimicrobial agents were examined in a reference strain <i>Campylobacter jejuni</i> ATCC 33560 and 73 thermo-tolerant isolates of <i>Campylobacter</i> spp. For the microdilution method and all tested antimicrobial agents, our determined values of microbiological breakpoints of resistant strains were suggested as the minimum inhibitory concentration (MIC<sub>R</sub>) for ciprofloxacin &ge; 0.5, erythromycin &ge; 4, gentamicin &ge; 4, nalidixic acid &ge; 32 and tetracycline &ge; 4 &mu;g/ml. On the basis of our study results, strains resistant to clindamycin were MIC<sub>R</sub> &ge; 2 &mu;g/ml for the dilution methods and a zone diameter R ≤ 16 mm for the disk diffusion method. Comparison of the results of the resistance examination, a microdilution method and disk diffusion method with the reference agar dilution method, showed that all compared methods yielded identical results with the exception of the resistance determination in erythromycin and nalidixic acid. The errors were mostly the result of the interpretation criteria for MIC<sub>R</sub> of agar dilution method and different conditions of cultivation used. However, the compared methods, provide results comparable with the reference method having greater convenience of measurement.

scholarly journals Inaccuracy of the Disk Diffusion Method Compared with the Agar Dilution Method for Susceptibility Testing of Campylobacter spp.

2011 ◽  
Vol 50 (1) ◽  
pp. 52-56 ◽  
Author(s):  
Mirva Lehtopolku ◽  
Pirkko Kotilainen ◽  
Pauli Puukka ◽  
Ulla-Maija Nakari ◽  
Anja Siitonen ◽  
...  
Keyword(s):  
Susceptibility Testing ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Disk Diffusion Method ◽  
Agar Dilution ◽  
Campylobacter Spp

scholarly journals Categorizing susceptibility of clinical isolates of Candida auris to amphotericin B, caspofungin, and fluconazole utilizing the CLSI M44-A2 disk diffusion method

2021 ◽  
Author(s):  
Natalie S. Nunnally ◽  
Tajah Damm ◽  
Shawn R. Lockhart ◽  
Elizabeth L. Berkow
Keyword(s):  
Amphotericin B ◽  
Accurate Method ◽  
Clinical Isolates ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
Broth Microdilution ◽  
Candida Auris ◽  
Disk Diffusion Method ◽  
Microdilution Method ◽  
Broth Microdilution Method

We evaluated the CLSI M44ed3E disk diffusion method in comparison with the CLSI M27ed4 broth microdilution method for caspofungin and fluconazole and the Etest method for amphotericin B to categorize susceptibility of 347 clinical isolates of Candida auris. Utilizing the zone diameter cutoffs established here we observed the overall categorial agreement between the two methods. For caspofungin, concordant results were observed for 98% of isolates with <1% very major and 1% major errors. For fluconazole, concordant results were observed for 91% of isolates with 1% very major and 8% major errors. For amphotericin B, concordant results were observed for 74% of isolates with <1% very major errors and 25% major errors. The disk diffusion approach provides an accurate method for determining the susceptibility of C. auris for caspofungin and fluconazole, and for identification of at least 75% of amphotericin B-susceptible isolates.

In Vitro Antimicrobial Activity of Javanese Tamarind Leaves Infusion (Tamarindus indica Linn.) in Escherichia coli

2015 ◽  
Vol 1 (1) ◽  
Author(s):  
Caroline Suryadi ◽  
Djaja Rusmana ◽  
Endang Evacuasiany
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Activity ◽  
Antimicrobial Effect ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
Dilution Method ◽  
Tamarindus Indica ◽  
Disk Diffusion Method ◽  
Average Growth ◽  
Zones Of Inhibition

Escherichia coli is the most common bacteria that cause diarrhea. Based on Kurniawati’s research, ethanol extract of tamarind leaves has an antimicrobial effect to Escherichia coli. This study aims to determine the antimicrobial effect using disk diffusion method, the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of tamarind leaves infusion against Escherichia coli. This research was done using a real laboratory experimental design with tamarind leaves infusion and Escherichia coli microbes as the research objects. Zones of inhibition were observed using disk diffusion method by putting the tamarind leaves infusion disks on Mueller-Hinton agars with Ampicillin antibiotic for comparison, followed by observing the MIC using macro broth dilution method  and MBC. The result of disk diffusion showed that tamarind leaves infusion had no zone of inhibition, whereas the mean value of the zones of inhibition of ampicillin is 17.2 mm. The MIC of tamarind leaves infusion is 62.5 mg/mL. Average growth of bacteria  for the MBC of tamarind leaves infusion at 125 mg/mL and 62.5 mg/mL concentration are 13 CFU/mL and >300 CFU/mL. It can be concluded that tamarind leaves infusion has antimicrobial activity effect against E.coli and that effect is bacteriostatic. Keywords: Tamarindus indica Linn, Escherichia coli, MIC, MBC

Biocide's susceptibility and frequency of biocide resistance genes and the effect of exposure to sub-inhibitory concentrations of sodium hypochlorite on antibiotic susceptibility of Stenotrophomonas maltophilia

2021 ◽  
Author(s):  
Safar Ali Alizadeh ◽  
Amir Javadi ◽  
Farhad Nikkhahi ◽  
Mohammad Rostamani ◽  
Mehdi Bakht ◽  
...  
Keyword(s):  
Sodium Hypochlorite ◽  
Resistance Genes ◽  
Antibiotic Susceptibility ◽  
Inhibitory Concentration ◽  
Microtiter Plate ◽  
Multidrug Resistant ◽  
Diffusion Method ◽  
Dilution Method ◽  
Disk Diffusion Method ◽  
Microtiter Plate Assay

Background: The overused of biocides in healthcare-facilities poses risk for emergence and spread of antibiotic resistance among nosocomial pathogens. Hospital-acquired infections due to S. maltophilia particularly in the immunocompromised patients have been increased. The objective of this study was to evaluate the susceptibility of S. maltophilia clinical isolates to commonly used biocides in hospitals, as well the frequency of biocides resistance gene among them. This study also intended to assess the effect of exposure of S. maltophilia isolates to sub-inhibitory concentrations of sodium hypochlorite upon the antimicrobial susceptibility patterns. Methods: This study included 97 S. maltophilia isolates. Biofilm formation was determined by microtiter plate assay. The susceptibility tests of five biocides were studied against all S. maltophilia isolates by microbroth dilution method. Susceptibility of isolates to antibiotics by disk diffusion method were compared before and after exposure to sub-inhibitory concentrations of sodium hypochlorite. Presence of qacE, qacEΔ1, SugE genes was screened by PCR. Results: Based on minimum inhibitory and bactericidal concentrations of biocides sodium hypochlorite 5% and ethyl alcohol 70% were the strongest and weakest against S. maltophilia isolates, respectively. The frequency of sugE gene resistance genes was found to be high (90.7%) in our clinical S. maltophilia isolates. None of the isolates carried qacE and qacEΔ1 gene. Exposure to sub-inhibitory concentration of sodium hypochlorite showed significantly change the susceptibility of isolates towards ceftazidime (P = .019), ticarcillin/clavulanate (P = .009). and chloramphenicol (P = .028). Conclusions: This study demonstrated that exposure to sub-inhibitory concentration of sodium hypochlorite leads to reduced antibiotic susceptibility and development of multidrug-resistant S. maltophilia strains.

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.

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