Minimal inhibitory concentration of ceftazidime and Co-trimoxazole for Stenotrophomonas maltophilia using E-test

Abstract

BackgroundStenotrophomonas maltophilia, previously named as Pseudomonas or Xanthomonas maltophilia, is an important nosocomial pathogenAimThe purpose of the present study was to investigate the prevalence of S. maltophilia in Iranian hospitals and its susceptibility to available antimicrobial agents.Setting and design:A cross-sectional study in Imam Khomeini Hospital affiliated to Tehran University of Medical Sciences.Materials and MethodsAll blood specimens were sent to the laboratory for blood culture and biochemical analysis. One hundred samples were positive for S. maltophilia. We used disk diffusion and E-test in order to determine minimal inhibitory concentration (MIC) of ceftazidime and co-trimoxazole as the first line antibiotics for S. maltophilia. The tests were performed and interpreted according to the guidelines of Clinical Laboratory Standards Institute (CLSI).Statistical analysis:Chi-square test and Kappa measurement of agreement were applied as appropriate.ResultsS. maltophilia was the most frequent pathogen (895 specimens; 38.9%) isolated from the samples which were mostly from emergency ward (780 specimens; 33.9%). Ceftazidime MIC50 and MIC90 were 2 and 32 μg/ml, respectively (sensitive ≤8 μg/ml and resistant ≥32 μg/ml according to CLSI guideline). MIC50 and MIC90 for co-trimoxazole were 0.5 and 2 μg/ml, respectively (sensitive ≤2 μg/ml and resistant ≥4 μg/ml according to CLSI guideline).ConclusionS. maltophilia is the most frequent pathogen in our hospital with a high susceptibility to both ceftazidime and co-trimoxazole.

Characterization of Phenotypic and Genotypic Diversity of Stenotrophomonas maltophilia Strains Isolated From Selected Hospitals in Iran

“…A study by Jamali et al. showed that susceptibility of S. maltophilia against ceftazidime was 82% with the MIC 50 and MIC 90 values of 2 and 32 μg/ml, respectively (Jamali et al., 2011). Shahla et al.…”

“…Jamali et al. showed about 60% susceptibility rate for TMP-SMX and the MIC 50 and MIC 90 values were 0.5 and 2 μg/ml (Jamali et al., 2011). In our study, based on the CLSI recommended dose of TMP-SMX, the resistance rate of 3.04% and the MIC 50% and MIC 90% values of 2.38 and 4.76 were found, respectively.…”

Antibiotic resistance, biofilm formation, and biofilm-associated genes among Stenotrophomonas maltophilia clinical isolates

“…A study by Farrell et al showed that susceptibility of S. maltophilia against ceftazidime was 32.51% in Latin America, North America, Asian-Pacific, and Europe [ 26 ]. In contrast, Jamali et al reported the susceptibility rate of 82% against this drug [ 27 ]. In our study, 100% and 95.29% of S. maltophilia were susceptible to minocycline and levofloxacin, respectively.…”

Medical Management of Endocarditis Caused by Stenotrophomonas maltophilia: A Case Report

“…8,10 Some in vitro data also support the use of cefepime, ceftazidime, tigecycline, and ticarcillin–clavulanic acid. 11 -13 To our knowledge, this is the first report of S maltophilia endocarditis that was treated with minocycline as an adjunct to other antibiotics.…”