Colistin susceptibility testing by Etest and disk diffusion methods

Galani, Irene; Kontopidou, Flora; Souli, María; Rekatsina, Panagiota-Danai; Koratzanis, Evangelos; Deliolanis, John; Giamarellou, Helen

doi:10.1016/j.ijantimicag.2008.01.011

Cited by 129 publications

(101 citation statements)

References 29 publications

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“…Besides testing colistin susceptibility by Vitek 2 compact system, the disc diffusion method using 10 μg disc was also done (≤ 12 mm = resistant and ≥ 14 mm = susceptible) [16]. Since neither the current CLSI nor EUCAST provided disc diffusion zone diameter breakpoints for colistin against Acinetobacter spp., and since both recommended that colistin testing should be performed by dilution method and interpreted according to MIC, colistin susceptibility disc diffusion results were compared against broth microdilution method (as a reference method) [ …”

Section: Disc Diffusion Testmentioning

confidence: 99%

In Vitro Activity of Colistin and Vancomycin or Azithromycin Combinations on Extensively Drug Resistant Acinetobacter baumannii Clinical Isolates

Okasha¹,

Meheissen²

2017

AiM

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Background: Extensively drug resistant Acinetobacter baumannii (XDR-AB) presents an increasing challenge to health care in Egypt as they are among the most common bacteria isolated in hospital setting. Treatment of such infections usually involves the use of antimicrobial agents in combination. Various combinations have been proposed, with colistin serving as the backbone in many of them even for colistin resistant isolates. Aim: The study was conducted in order to test the in vitro combined effects of colistin and vancomycin or azithromycin against (XDR-AB) causing infections at Alexandria Main University Hospital in Egypt, in an attempt to detect the possibility of a beneficial combination therapy. Material/Methods: Thirty XDR-AB clinical isolates were included in the study. Antibiotic susceptibility testing was performed using automated Vitek 2 compact system and disc diffusion method. Colistin antibiotic disc diffusion test was compared with broth microdilution method. Organisms were also tested against colistin and vancomycin or azithromycin in combination using checkerboard synergy test and FICI (Fractional Inhibitory Concentration Index) was calculated. Synergy was defined as a FICI of ≤0.5. Results: On comparing the two methods used to detect susceptibility to colistin to broth microdilution for MIC (minimum inhibitory concentration) determination, as a reference method, the Vitek showed 100% categorical agreement (CA), on the other hand, the disc diffusion showed CA of 93% with very major errors. Synergy was detected for all isolates (100%) when combining colistin with vancomycin (FICI mean = 0.08). As for azithromycin, 21 strains had FICI range from 0.7 to 1.001, denoting indifference; the remaining 9 strains showed synergy with FICI range from 0.06 to 0.241. The mean colistin/azithromycin FICI was 0.71 for the 30 isolates. Conclusion: These findings suggest that regimens containing vancomycin may confer therapeutic benefit for infection due to XDR-AB; however, other methods (time-kill assay) should be used to confirm such synergy. Furthermore, the optimal combination treatment for serious XDR-AB infection should be addressed in a prospective clinical trial.

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Section: Disc Diffusion Testmentioning

confidence: 99%

In Vitro Activity of Colistin and Vancomycin or Azithromycin Combinations on Extensively Drug Resistant Acinetobacter baumannii Clinical Isolates

Okasha¹,

Meheissen²

2017

AiM

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“…Colistin susceptibility was also performed using a disk diffusion method. 43 Stool samples from healthy food animal farm workers, water samples, and swabs from fresh and cooked foods, healthy food animals, and fresh pork meat samples were inoculated onto MacConkey agar, MacConkey agar supplemented with ceftriaxone, mannitol salt agar (selective for Staphylococci), and enterococcal agar supplemented with vancomycin [selective for vancomycin-resistant Enterococcus species (VRE)]. The inoculated plates were incubated at 35uC for 24 hours.…”

Section: Bacterial Culture and Antibiotic Susceptibility Testmentioning

confidence: 99%

Prevalence of antibiotic resistant bacteria in healthy adults, foods, food animals, and the environment in selected areas in Thailand

Boonyasiri

Tangkoskul

Seenama

et al. 2014

Pathogens and Global Health

121

110

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Objectives: The aim of this study was to determine the prevalence of antibiotic-resistant bacteria, especially extended-spectrum beta-lactamase (ESBL) producing Escherichia coli, in samples from healthy adults, foods, food animals, and the environment in selected areas of Thailand. Methods: Samples were collected from stool specimens from adult food factory and food animal farm workers, fresh and cooked foods sold at markets, rectal swabs of healthy pigs and chickens, fresh pork meat from slaughterhouses, water samples from canals as well as fish and shrimp farm ponds, and stagnant water sources on pig farms. Antibiotic susceptibility was determined using the disk diffusion or agar dilution methods. Extended-spectrum beta-lactamase production was assayed using a double disk diffusion method. Results: Among 544 healthy adult food factory workers, 75.5% were positive for ESBL producing E. coli, while 77.3% of E. coli isolated from 30 healthy animal farm workers were positive. Amongst healthy food animals, ESBL producing status among E. coli isolates were more commonly detected in pigs (76.7%) than broilers (40%). Extended-spectrum beta-lactamase producing E. coli seemed to be more prevalent in fresh meat samples than in fresh vegetables, in fresh foods than in cooked foods, and in water samples collected from the animal farms than those from canals and fish and shrimp ponds. Conclusions: Extended-spectrum beta-lactamase producing E. coli isolates are prevalent amongst healthy individuals, foods along the food production chain from farms to consumers, and in the environment in selected areas in Thailand.

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“…The conjugation experiment was carried out in mixed-broth cultures as previously described (15), and rifampin-resistant Escherichia coli EC600 (LacZ Ϫ Nal r Rif r ) was used as the recipient strain. The MICs of meropenem, imipenem, ertapenem, colistin, tigecycline, ceftazidime, ciprofloxacin, piperacillin-tazobactam, cefoxitin, and amikacin were determined by the Etest technique (AB bioMerieux, Sweden) according to the manufacturer's instructions, and the susceptibility breakpoints were interpreted as recommended by the Clinical and Laboratory Standards Institute (CLSI) and previous reports (5,9). Plasmid pKP048 from strain KP048 was completely sequenced by using a shotgun approach (15).…”

mentioning

confidence: 99%

Complete Nucleotide Sequence of Klebsiella pneumoniae Multidrug Resistance Plasmid pKP048, Carrying bla _KPC-2 , bla _DHA-1 , qnrB4 , and armA

Jiang

Wei

et al. 2010

Antimicrob Agents Chemother

109

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The Klebsiella pneumoniae multidrug resistance plasmid pKP048 was completely sequenced. This plasmid carries several important resistance determinants, such as bla KPC-2 , bla DHA-1 , qnrB4, and armA, which confer resistance to carbapenems, cephalosporins, fluoroquinolones, and aminoglycosides, respectively. Analysis of the finished 151,188-bp sequence data revealed 163 putative genes, 108 of which were assigned functions such as replication, stable inheritance, antibiotic resistance, a mobile element, conjugal transfer, and a restrictionmodification system, showing the strong phylogenetic mosaicism and plasticity of the plasmid.

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Colistin susceptibility testing by Etest and disk diffusion methods

Cited by 129 publications

References 29 publications

<i>In Vitro</i> Activity of Colistin and Vancomycin or Azithromycin Combinations on Extensively Drug Resistant <i>Acinetobacter baumannii</i> Clinical Isolates

<i>In Vitro</i> Activity of Colistin and Vancomycin or Azithromycin Combinations on Extensively Drug Resistant <i>Acinetobacter baumannii</i> Clinical Isolates

Prevalence of antibiotic resistant bacteria in healthy adults, foods, food animals, and the environment in selected areas in Thailand

Complete Nucleotide Sequence of Klebsiella pneumoniae Multidrug Resistance Plasmid pKP048, Carrying bla _KPC-2 , bla _DHA-1 , qnrB4 , and armA

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Colistin susceptibility testing by Etest and disk diffusion methods

Cited by 129 publications

References 29 publications

&lt;i&gt;In Vitro&lt;/i&gt; Activity of Colistin and Vancomycin or Azithromycin Combinations on Extensively Drug Resistant &lt;i&gt;Acinetobacter baumannii&lt;/i&gt; Clinical Isolates

&lt;i&gt;In Vitro&lt;/i&gt; Activity of Colistin and Vancomycin or Azithromycin Combinations on Extensively Drug Resistant &lt;i&gt;Acinetobacter baumannii&lt;/i&gt; Clinical Isolates

Prevalence of antibiotic resistant bacteria in healthy adults, foods, food animals, and the environment in selected areas in Thailand

Complete Nucleotide Sequence of Klebsiella pneumoniae Multidrug Resistance Plasmid pKP048, Carrying bla KPC-2 , bla DHA-1 , qnrB4 , and armA

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Product

Resources

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<i>In Vitro</i> Activity of Colistin and Vancomycin or Azithromycin Combinations on Extensively Drug Resistant <i>Acinetobacter baumannii</i> Clinical Isolates

<i>In Vitro</i> Activity of Colistin and Vancomycin or Azithromycin Combinations on Extensively Drug Resistant <i>Acinetobacter baumannii</i> Clinical Isolates

Complete Nucleotide Sequence of Klebsiella pneumoniae Multidrug Resistance Plasmid pKP048, Carrying bla _KPC-2 , bla _DHA-1 , qnrB4 , and armA