[Drug susceptibility and homologous analysis on Corynebacterium striatum strains isolated from inpatients]

To explore the molecular epidemiological features and in vitro susceptibility profile of Corynebacterium striatum strains isolated from different sites of inpatients, and further provide new data and idea for clinicians to better get knowledge of the clinical significance of Corynebacterium striatum.

Fourty-five strains of Corynebacterium striatum isolated from different sites of inpatients from November, 2013 to March, 2014 in Affiliated hospital of Inner Mongolian medical university, and microdilution method was employed to do in vitro antibiotics susceptibility test. Saline-cotton swab method was used to sample the surrounding environmental surfaces for Corynebacterium striatum carrying patients, and suspected colonies were further identified and in vitro drug susceptibility test were performed. Pulsed Field Gel Electrophoresis(PFGE) method was used to do molecular typing for 41 isolates of Corynebacterium striatum.

Fourty-five isolates of Corynebacterium striatum strains were mainly isolated from neurosurgical unit(21 isolates), respiratory unit(8 isolates) and intensive care unit(8 isolates), 39 isolates of which were isolated from lower respiratory tract. The 45 isolates presented an aggregate distribution in the following 3 months, which were December 2013, January 2014 and February 2014.In vitro antibiotics susceptibility test showed that MIC90 for penecillin, erythromycin, tetracycline, ciprofloxacin and clindamycin were 64 µg/ml or higher and the MIC90 for gentamicin, vancomycin and rifampicin were all 0.5 µg/ml. Only one isolate was sensitive to all of the antibiotics tested, except clindamycin. PFGE typing results showed that 41 isolates were divided into 7 genotypes, among which 0002 type and 0006 type were the predominant types and accounted for 63% (26/41) and 22% (9/41), respectively. The isolates from different patients showed high homology, which were isolated from the same unit during the same periods.For surrounding surfaces sampling, Corynebacterium striatum isolating rate was 40% (8/20). The isolates from environmental surfaces and those from the corresponding patients showed identical drug susceptibility profiles.

Corynebacterium striatum isolated from inpatients show multi-drug resistant profile, and different isolates from different patients are highly homologous. Specific units, such as neurosurgery unit, respiratory unit and intensive care unit, should reevaluate the clinical significance of Corynebacterium striatum and its relationship with clinical treatment measures supplemented.