[Resistance monitoring working group: resistance to erythromycin, ciprofloxacin, and tetracycline in human isolates of Campylobacter spp. in the Czech Republic tested by the EUCAST standard method]

Abstract

Study aim: To determine the frequency of Campylobacter spp. isolated from humans in the Czech Republic and to test their susceptibility to antimicrobials commonly used to treat campylobacteriosis by the standard EUCAST method.

Material and methods: Consecutive Campylobacter isolates recovered from clinical specimens in 49 microbiological laboratories within one month in 2013 were identified using matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS). Susceptibility to erythromycin, ciprofloxacin, and tetracycline was tested by the microdilution method and the results were interpreted based on the EUCAST clinical breakpoints to differentiate between susceptible and resistant strains.

Results: Of the study set of 769 Campylobacter spp. strains, 90.1 % were assigned to C. jejuni, 9.8 % to C. coli, and a single strain to C. fetus (0.1 %). Except one blood isolate of C. jejuni, all other isolates were recovered from the stool. Ciprofloxacin resistance (MIC > 0.5 mg/l) was detected in 61.9 % strains of C. jejuni and in 72.0 % strains of C. coli, tetracycline resistance (MIC > 2 mg/l) was detected in 32.0 % of strains of both species, and erythromycin resistance was found in 0.3 % of strains of C. jejuni (MIC > 8 mg/l) and in 2.7 % of strains of C. coli (MIC > 4 mg/l). A C. coli strain was multidrug resistant (i.e. resistant to all three antimicrobials tested).

Conclusions: Despite the fact that most Campylobacter infections in humans cure on their own, the resistance of the causative strains to the antimicrobials of choice and alternative agents needs to be studied because of its relevance to the treatment of severe cases that require antibiotics. Resistance to macrolides was found rather infrequently in this study in both C. jejuni (0.1 %) and C. coli (2.7 %) strains. Nevertheless, alarming is ciprofloxacin resistance confirmed in 61.9 % of C. jejuni strains and 72.0 % C. coli strains. As the species C. coli is more often resistant to antimicrobials than C. jejuni and ciprofloxacin along with other fluoroquinolones is commonly used to treat severe food-borne and generalized infections, it is crucial to identify the Campylobacter strains to the species level and to test their susceptibility to relevant antibiotics by a valid and reproducible method to be able to provide an effective therapy.