P2447 Pivmecillinam susceptibility in urinary tract infections - a prospective study of an old in the new multidrug-resistance era

Frieder Fuchs*1, Axel Hamprecht1 2

1Institut für Medizinische Mikrobiologie, Immunologie und Hygiene, Köln, Germany, 2DZIF (German Centre for Infection Research), partner site Cologne-Bonn

Background:

The increase in antibiotic resistance of Enterobacteriaceae has complicated the treatment of urinary tract infections (UTI), since few options for oral therapy remain. Pivmecillinam (PCM) is an oral beta- lactam antibiotic which has regained interest because of low resistance in Enterobacteriaceae. Recently been released in Germany, few susceptibility data of PCM are available. Therefore, we prospectively analysed PCM susceptibility in all Escherichia coli, Klebsiella spp. and Proteus mirabilis isolates in two cohorts: I all urine samples from a single community hospital from 11/2016-3/2017 and II all urines with multidrug-resistant isolates (MDR) sent to the Institute for Medical Microbiology.

Material/methods:

UTI isolates were identified by MALDI-TOF mass spectrometry. Susceptibility testing was done by Vitek2 except for PCM which was tested by disk diffusion according to EUCAST standards. In case of PCM resistance and for all MDR, minimal inhibitory concentrations (MICs) were determined using MIC test strips (Liofilchem, Roseto degli Abruzzi, Italy).

Results:

In group I, E. coli was the most frequent species (N=257), followed by Klebsiella spp. (N=41) and P. mirabilis (N=30). In E. coli resistance to PCM was observed in 4.3% of all (11/257) and in 10% of ESBL-/AmpC-producing isolates (4/41). Ten percent of Klebsiella spp. (4/41) and 13% (4/30) of P. mirabilis were PCM resistant. In group II (MDR, mostly ESBL) 105 isolates of E. coli (N=86) and Klebsiella spp. (N=19) were tested. PCM was susceptible in 92% (87/105), including two of three carbapenemase-producers (all K. pneumoniae OXA-48).

Conclusions:

The study confirmed the good activity of PCM against the most important Enterobacteriaceae causing UTI. Susceptibility of PCM is higher in E. coli than in Klebsiella spp. or P. mirabilis. Additionally, in MDR Enterobacteriaceae the susceptibility of PCM is high compared to most other , including - and only slightly lower than or (Figure 1). PCM therapy should be considered in uncomplicated UTI as an oral agent with high susceptibility, especially in patients with known MDRs.