Emergence of colistin resistant K.pnenomonia isolates in Payvand clinical and specialty laboratory ; a ۶ month survey

Background and Aim : Emergence of multi drug resistant bacteria (MDR, resistant to ۳ classesof antibiotics ) and more serious extensively drug-resistant bacteria (XDR, almost resistant to allor all approved antimicrobial agents) are global challenges. Colistin, is the last available antibioticfor treatment of carbapenem resistant enterobacteriacea. So, in this study emergence of colistinresistant K. pnenomonia isolates in Payvand clinical and specialty laboratory was evaluated in a ۶month study.Methods : From Sep ۲۰۲۱ to March ۲۰۲۲, ۵۷۳۶ different clinical samples from ۵۸۶۵ patients whoreferred to Payvand clinical and specialty laboratory were included in this study. Further colonyisolation was done based on standard protocol using bacterial media, streak culture and routineincubation at ۳۷ºC. Bacterial identification and antimicrobial test (AST) was done by usingautomated Vitec۲ system (Biomerieux, France) and using GN ۲ and GN۷۶ cards respectivelybased on the CLSI protocol. The AST were reported as minimum inhibitory concentration (MIC).Colistin resistant was done on selected XDR K. pnenumonia isolates using N۲۴۰ card. Furtherstatistical analysis was done.Results : ۸۶۳ of ۵۷۳۶ (۱۵.۰۴%) of clinical samples (including: broncoalveolar lavage (Bal),sputum, wound, blood and urine) were culture positive. Of them ۱۳۰ isolates were identified as K.pneumonia and ۱۶.۹۲% (۲۲/۱۳۰) of them were resistant to all tested antibiotics (including: Amp,TZP, CFZ, Fox, Caz, CRO, FEP, ERTA, IMP, An, GM, CP, Levo, FM and SXT) and identifiedas extended drug resistant (XDR). These ۲۲ XDR K. pneumonia strains were isolated from ۱۲female and ۸ male patients. ۱۲/۲۲ K, pneumonia isolates showed intermediate resistant (I) and ۱۰were colistin resistant(R).Conclusion : Although, sample collection of only a clinical laboratory in Tehran is a limitation ofthis study but high rate of XDR K. pneumonia with no susceptibility to colistin seems alarmingand needs especial notification on antibiotic stewardship, infection control and antibioticprescription.

کلیدواژه ها:

klebsiella pneumonia ، Colistin ، resistant