gms | German Medical Science

Objective: Analysis of the taxonomic structure of sepsis pathogens in cancer patients with bacteriemia/fungemia during their stay in ICU, using automated microbiological systems, and rapid identification of bacterial and fungal pathogens from blood.

Methods: Microbiological study of blood samples, obtained during 182 episodes of sepsis 2011–2013, was conducted using haemoanalyzer BACTEC FX 400 with subsequent identification by MALDI-TOF MS Microflex. Preparation with MALDI Sepsityper Kit 50 required only 20 minutes to identify microorganism from the blood after a positive signal of haemanalyzer. Antimicrobial susceptibility testing was performed with MicroscanWalkAway (Siemens, Germany). Clinical significance of blood culture was determined in accordance with the CDC criteria.

Results: 158 bacterial and fungal strains were analyzed. Gram-negative rods accounted for 53.8 %, gram-positive cocci – for 35.4% (p <0.02) and fungi – for 10.8 %. Klebsiella pneumoniae (28.5%) and Acinetobacter baumannii (13.9%) prevailed among gram-negative rods, as the result of two sequential epidemiological outbreaks of nosocomial infection in ICU. These strains were multidrug-resistant and resistant to carbapenems. Klebsiella pneumoniae was sensitive only to amikacin and tigecycline, but the treatment with these drugs was ineffective with mortality rate of 66%. A.baumannii had extreme drug-resistance and was susceptible only to colistin. MIC A.baumannii for sulbactam did not exceed 32mkg/mkl, permitting the use of high doses of ampicillin/sulbactam (24g/day) with a good success. Other enterobacteria accounted for 5.1%, Pseudomonas aeruginosa for 3.2%, Stenotrophomonas maltophilia for 3.2%, coagulase-negative staphylococci for 25.3% and Staphylococcus aureus for 0,6%. Enterococci were presented with E.faecium (5.1%) and E.faecalis (4.4%). Fungi were presented with Candida spp. with the prevalence of C.parapsilosis (7.0%), C.guillermondii accounted for 2.5% and C.albicans for 1.3%.

Conclusion: The use of modern microbiological analyzers and rapid identification methods of preparation to identification helps to reduce the time for obtaining microbiological results and to assign rational antimicrobial therapy in a shorter time.