Determination of Colistin Resistance by Simple Disk Diffusion Test Using Modified Mueller-Hinton Agar

Uwizeyimana, Jean Damascene; Kim, Daewon; Lee, Hyun‐Sook; Byun, Jung Hyun; Yong, Dongeun

doi:10.3343/alm.2020.40.4.306

Cited by 20 publications

(18 citation statements)

References 22 publications

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“…The microdilution broth method, as well as the Etest, determine MIC values that can be used by clinicians to address antibiotic therapy options; whereas, the disk diffusion is a qualitative test based on a diameter of inhibition zone, which cannot be easily converted into a MIC value, but only allowing to describe bacteria as “drug susceptible”, “intermediate” and “drug resistant”. Although simple and performed in many laboratories, the disk diffusion assay presents some limitations including low reproducibility and inaccurate inhibition diameter determination [ 26 , 27 , 28 , 29 ]. The results from disk diffusion test performed for cefiderocol on our MDR A. baumannii clinical isolates, were not fully coherent with data obtained by using the “gold standard” broth dilution method due to the variability observed amongst technical replicates.…”

Section: Discussionmentioning

confidence: 99%

In Vitro Antimicrobial Activity of the Siderophore Cephalosporin Cefiderocol against Acinetobacter baumannii Strains Recovered from Clinical Samples

et al. 2021

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Background: Cefiderocol is a siderophore cephalosporin that exhibits antimicrobial activity against most multi-drug resistant Gram-negative bacteria, including Enterobacterales, Pseudomonas aeruginosa, Acinetobacter baumannii, and Stenotrophomonas maltophilia. Methods: A total of 20 multidrug-resistant A. baumannii strains were isolated from 2020 to 2021, molecularly characterized and tested to assess the in vitro antibacterial activity of cefiderocol. Thirteen strains were carbapenem-hydrolysing oxacillinase OXA-23-like producers, while seven were non-OXA-23-like producers. Minimum inhibitory concentrations (MICs) were determined by broth microdilution, considered as the gold standard method. Disk diffusion test was also carried out using iron-depleted CAMHB plates for cefiderocol. Results: Cefiderocol MICs ranged from 0.5 to 1 mg/L for OXA-23-like non-producing A. baumannii strains and from 0.25 to >32 mg/L for OXA-23-like producers, using the broth microdilution method. Cefiderocol MIC90 was 8 mg/L. Diameter of inhibition zone of cefiderocol ranged from 18 to 25 mm for OXA-23-like non-producers and from 15 to 36 mm for OXA-23-like producers, using the diffusion disk method. A large variability and a low reproducibility were observed during the determination of diameter inhibition zone. Molecular characterization showed that all isolates presented the ISAba1 genetic element upstream the blaOXA-51. Among OXA-23-like non-producers, four were blaOXA-58 positive and two were negative for all the resistance determinants analyzed. Conclusions: Cefiderocol showed in vitro antimicrobial activity against both carbapenem-susceptible and non-susceptible A. baumannii strains, although some OXA-23-like producers were resistant. Further clinical studies are needed to consolidate the role of cefiderocol as an antibiotic against MDR A. baumannii.

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Section: Discussionmentioning

confidence: 99%

In Vitro Antimicrobial Activity of the Siderophore Cephalosporin Cefiderocol against Acinetobacter baumannii Strains Recovered from Clinical Samples

et al. 2021

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“…We adopted the Simple Disk diffusion method using modified muller-hinton agar as described by Uwizeyimana et al to test the susceptibility of all the multidrug-resistant (MDR) gram-negative bacteria (GNB) (32/67) to colistin [ 34 ]. Briefly, an isolate suspension equivalent to 0.5 McFarland standard was prepared and plated on modified Mueller–Hinton agar 30% (5.1 g/L) (Oxoid, United Kingdom), allowed to dry for 3–5 min, a 10 mg colistin disk was placed and incubated overnight at 35℃ in 5% CO2.…”

Section: Methodsmentioning

confidence: 99%

Multidrug resistant bacterial infections in severely ill COVID-19 patients admitted in a national referral and teaching hospital, Kenya

2022

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Background Bacterial infections are a common complication in patients with seasonal viral respiratory tract infections and are associated with poor prognosis, increased risk of intensive care unit admission and 29–55% mortality. Yet, there is limited data on the burden of bacterial infections among COVID-19 patients in Africa, where underdeveloped healthcare systems are likely to play a pertinent role in the epidemiology of the COVID-19 pandemic. Here, we evaluated the etiologies, antimicrobial resistance profiles, risk factors, and outcomes of bacterial infections in severely ill COVID-19 patients. Methods A descriptive cross-sectional study design was adopted in severely ill COVID-19 patients at Kenyatta National Hospital, Kenya, from October to December 2021. We used a structured questionnaire and case report forms to collect sociodemographics, clinical presentation, and hospitalization outcome data. Blood, nasal/oropharyngeal swabs and tracheal aspirate samples were collected based on the patient's clinical presentation and transported to the Kenyatta National Hospital microbiology laboratory for immediate processing following the standard bacteriological procedures. Results We found at least one bacterial infection in 44.2% (53/120) of the patients sampled, with a 31.7% mortality rate. Pathogens were mainly from the upper respiratory tract (62.7%, 42/67), with gram-negative bacteria dominating (73.1%, 49/67). Males were about three times more likely to acquire bacterial infection (p = 0.015). Those aged 25 to 44 years (p = 0.009), immunized against SARS-CoV-2 (p = 0.027), and admitted to the infectious disease unit ward (p = 0.031) for a short length of stay (0–5 days, p < 0.001) were more likely to have a positive outcome. Multidrug-resistant isolates were the majority (64.3%, 46/67), mainly gram-negative bacteria (69.6%, 32/46). The predominant multidrug-resistant phenotypes were in Enterococcus cloacae (42.9%, 3/7), Klebsiella pneumonia (25%, 4/16), and Escherichia coli (40%, 2/5). Conclusion Our findings highlight a high prevalence of multidrug-resistant bacterial infections in severely ill COVID-19 patients, with male gender as a risk factor for bacterial infection. Elderly Patients, non-SARS-CoV-2 vaccination, intensive care unit admission, and long length of hospital stay were associated with poor outcomes. There is a need to emphasize strict adherence to infection and prevention at KNH-IDU and antimicrobial stewardship in line with local and global AMR control action plans.

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“…The culture was incubated at the selected levels of temperature using WFT scienti c incubator. The bacterial metabolites produced in the growth media were extracted in methanol and subjected to analysis of their APA against Pseudomonas aeruginosa and Escherichia coli in terms of zone of inhibition (ZOI) by the simple disk-diffusion method in Mueller Hinton agar (Uwizeyimana et al 2020). The Pseudomonas aeruginosa (CDC-54, PAO1) and Escherichia coli K12 (NCTC 10538) strains were obtained from the frozen stock (-80°C) of Biodiversity Collection Section (BDCS), Nuclear Institute of Agriculture and Biology (NIAB) Faisalabad, Pakistan.…”

Section: Anti-pathogenic Activity Of Bacterial Metabolitesmentioning

confidence: 99%

Response-surface optimization of anti-pathogenic activity of metabolic extracts obtained from rhizobacteria of Parthenium hysterophorus

Yousaf

Ibrahim

Nawaz

et al. 2022

Preprint

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The anti-pathogenic activity (APA) of the metabolic extracts obtained from rhizobacteria of Parthenium hysterophorus was optimized by constructing a tri-factorial central composited design in the response surface methodology. The colonies of the rhizobacteria isolated from the rhizospheric soil of P. hysterophorus were identified microscopically. The pink and yellow-colored colonies were cultured at five levels of three culture variables including pH (5, 6, 7, 8, and 9), incubation temperature (IT: 24, 28, 32, 36, and 40°C), and incubation time (It: 24, 48, 72, 96, and 120 h). The bacterial metabolites were extracted in methanol and analyzed for their APA against Pseudomonas aeruginosa and Escherichia coli. A statistically significant linear positive effect of pH was observed on the APA of both of the bacterial extracts and quadratic negative effect on APA of yellow-colored extracts against each of the selected pathogens. The It showed a significant linear positive effect on APA of the pink-colored extract against E. coli and that of the yellow-colored extract against the selected pathogens. It also showed quadratic negative effects on the APA of both of the bacterial extracts against the selected pathogens. However, the IT in the selected range showed no significant effect on the APA of the selected bacterial metabolites against the selected pathogens.

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Determination of Colistin Resistance by Simple Disk Diffusion Test Using Modified Mueller-Hinton Agar

Cited by 20 publications

References 22 publications

In Vitro Antimicrobial Activity of the Siderophore Cephalosporin Cefiderocol against Acinetobacter baumannii Strains Recovered from Clinical Samples

In Vitro Antimicrobial Activity of the Siderophore Cephalosporin Cefiderocol against Acinetobacter baumannii Strains Recovered from Clinical Samples

Multidrug resistant bacterial infections in severely ill COVID-19 patients admitted in a national referral and teaching hospital, Kenya

Response-surface optimization of anti-pathogenic activity of metabolic extracts obtained from rhizobacteria of Parthenium hysterophorus

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