Comparison of Antimicrobial Susceptibility Testing of Isolates from Blood Cultures by Direct Inoculation Method and PHOENIX

Background: Bloodstream infection (BSI) is an important cause of serious morbidity and mortality for hospitalized patients. Empirically Gram stain of bacteria gives the first clue for the etiology of infection and medical treatment. But the delayed treatment on 1 or 2 days after phenotypic identification and drug susceptibility testing may cause potential danger to patients. Rapid drug susceptibility testing can provide earlier information to guide treatment and in less time than bacterial culture and sensitivity testing, for antibiotics therapy. Methods: In this study, we excluded samples of polymicrobial bacteremia. We collected isolates from 815 infection episodes caused by Escherichia coli (57%), Klebsiella pneumoniae (20.16%), Enterobacter cloacae (6%), Ps. aeruginosa (9.1%), Stenotrophomonas maltophilia (3.1%), and Acinetobacter baumannii (3.1%) in a 10-month period. We identified those bacteria with direct susceptibility test with the use of Phoenix100 (BD) during a 10-month period. Results: The results of direct susceptibility were concordant (99%-100%) with those obtained from Phoenix100. Conclusion: These results have the potential to guide clinicians to initiate an early antimicrobial therapy in febrile patients with sepsis shock.