Methodological comparison of different antibiotic susceptibility testing for mucoid Pseudomonas aeruginosa / 中华检验医学杂志

ABSTRACT

Objective To compare the difference of three methods testing the antibiotic susceptibility of mucoid Pseudomonas aeruginosa in order to provide accurate and reliable antibiotic susceptibility result for clinic.Methods A total of 630 mucoid Pseudomonas aeruginosa were collected from Linyi People′s Hospital during January 2015 to December 2016.They mainly come from respiratory medicine and the most common specimen source was sputum.All specimens were examined in 2 h.The strains isolated from the same patient were discarded.Antibiotic susceptibility was tested by the automatic microorganism analyzer VITEK2 compact, E-test, which was reference method, and K-B disk.The results of three methods were analyzed and compared by χ2 test.Results The result of E-test showed that antibiotic sensitivity of 630 mucoid Pseudomonas aeruginosa was above 52.7% except for Cefepime (39.2%).The result of K-B disk was compared with E-test, the antibiotic sensitivity of mucoid Pseudomonas aeruginosa to imipenem (72.4% vs 52.7%) and amikacin (48.6% vs 71.1%)had significant difference (χ2=8.283 7 and 10.533 8, P<0.05).The result of VITEK2 compact showed that the antibiotic susceptibility of mucoid Pseudomonas aeruginosa to imipenem(70.8% vs 52.7%), cefepime(60.8% vs 39.2%), gentamicin (87.6% vs 74.1%)and levofloxacin(81.3% vs 65.4%) was significant higher than the result of E-test (χ2=6.935 2,9.331 2,5.885 6 and 6.466 5, P<0.05).For tobramycin, piperacillin/tazobactam and ciprofloxacin, the result of three methods is more consistent.Compared to VITEK2 compact, the consistency between K-B disk and E-test was higher.The rate of very major error and major error were between 0.0%-4.8% (Amikacin 12.2%) and minor error was 4.6%-20.3%.Conclusions The drug sensitivity of mucoid Pseudomonas aeruginosa is different between various methods.The result of K-B disk and E-test using blood MH is more reliable than VITEK2 compact.