Titel: Molecular surveillance of carbapenemase-producing Pseudomonas aeruginosa at three medical centres in Köln, Deutschland
ID: 56/PRV
Art: Abstractautor
Session: Workshop 11
Multi Drug Resistance: When, Who and Where does that take us? (FG PR, StAG HY)

Referent: Andreas Friedrich Wendel (Köln)

Abstract - Text


P. aeruginosa is a leading nosocomial pathogen. Resistance to carbapenems is either mediated via efflux pumps, loss of porin or carbapenemases. Carbapenemase-producing P. aeruginosa (CPP) strains are known to cause outbreaks and harbour a genetic reservoir. However, little surveillance data is available at the local level. The study was conducted in three medical centres in Cologne (one tertiary and one secondary care centre and one children hospital, 1500 beds).


Identification and susceptibility testing were performed with VITEK 2 system (bioMérieux). P. aeruginosa non-susceptible to piperacillin, ceftazidime, cefepime, imipenem, meropenem and ciprofloxacin (4MRGN according to the German classification) isolated from clinical and screening specimens from 2015 to 2017 were analysed. A two-step algorithm to detect carbapenemases was performed (phenotypic tests followed by PCR and sequencing). In case of contradictory results, isolates were sent to the German National Reference Centre. Inhibition zone diameters were determined with imipenem alone and in combination with (a) 930 mg EDTA or (b) 4000 mg Cloxacillin (difference of (a) ≥ 5 mm or (b) < 6 mm resp. was considered to be indicative of a carbapenemase). Subsequently CDT-positive isolates were further analysed by PCR and sequencing. CPP isolates were further genotyped by RAPD.


Seventy first 4MRGN-P. aeruginosa isolates were available for further analysis, of which 21 were CPP as follows: blaVIM-1 (n=2), blaVIM-2 (n=17), blaIMP (n=1) and blaNDM/blaGES (n=1). 15 CPP were hospital-acquired (specimen collected more than two days after admission), mostly from intensive care units (80%) and nearly all (except one) from the tertiary care centre. RAPD typing revealed two different clusters of VIM-2-producing P. aeruginosa containing 13 and 2 isolates each. However, using conventional epidemiology, we were only able to confirm three patient-to-patient transmissions and one room-to-patient transmission.


These data give insight into the epidemiology of CPP in three centres in Germany over a period of three years. Carbapenemases are a relevant resistance mechanism in 4MRGN-P. aeruginosa, VIM-2 being the most common carbapenemase. Genetically related strains seem to be endemic in the region. The results support the need for a local molecular surveillance system.