A multiresistant clone of Pseudomonas aeruginosa sequence type 773 spreading in a burn unit in Orumieh, Iran

Yousefi S, Nahaei MR, Farajnia S, Aghazadeh M, Iversen A, Edquist P, Maa˜ tallah M, Giske CG.
A multiresistant clone of Pseudomonas aeruginosa sequence type 773 spreading in a burn unit in
Orumieh, Iran. APMIS 2013; 121: 146–52.
Herein, we describe the phenotypic and genotypic characterization of a multiresistant clone of
Pseudomonas aeruginosa disseminating in a burn unit in Orumieh, Iran. A total of 58 isolates of
P. aeruginosa were collected during August 2007 and June 2008. Minimum inhibitory concentrations
(MICs) of P. aeruginosa isolates were determined against 11 antimicrobial agents by E test. Serotyping,
pulsed-field gel electrophoresis (PFGE), and multilocus sequence typing (MLST) were used for
studying the clonal relationship among the isolates. Antibiotic susceptibility testing revealed that
most of the isolates were multidrug resistant and colistin was the antibiotic with the highest activity.
Pseudomonas aeruginosa isolates fell into nine different serotypes, and O10 and O11 were the most
common. PFGE analyses showed 12 different genotypes and 68.1% of isolates showed more than
80% similarity, indicating possible clonal relatedness. These isolates were found to belong to the
same sequence type, ST773. This sequence type has earlier been reported from China, and a double
locus variant of this ST has been found earlier in France in a PER-1 extended-spectrum b-lactamase-
producing P. aeruginosa.