Results from the Survey of Antibiotic Resistance (SOAR) 2016-17 in Ukraine: data based on CLSI, EUCAST (dose-specific) and pharmacokinetic/pharmacodynamic (PK/PD) breakpoints.

OBJECTIVES

To determine antibiotic susceptibility of Streptococcus pneumoniae and Haemophilus influenzae isolates from community-acquired respiratory tract infections (CA-RTIs) collected in 2016-17 from Ukraine.

METHODS

MICs were determined by CLSI broth microdilution and susceptibility was assessed using CLSI, EUCAST (dose-specific) and pharmacokinetic/pharmacodynamic (PK/PD) breakpoints.

RESULTS

A total of 177 viable clinical isolates, including 78 S. pneumoniae and 99 H. influenzae, were collected. Overall, ∼98% of S. pneumoniae isolates were susceptible to penicillin by CLSI IV or EUCAST high-dose breakpoints and 73.1% were susceptible by CLSI oral or EUCAST low-dose IV breakpoints. Susceptibility rates of 76.9%-100% were observed for most antibiotics by all breakpoints except trimethoprim/sulfamethoxazole (41%-69.2%) and cefaclor, which showed the greatest difference between breakpoints: 0% by EUCAST, 28.2% by PK/PD and 73.1% by CLSI. All S. pneumoniae isolates were susceptible to amoxicillin/clavulanic acid by CLSI and PK/PD breakpoints. H. influenzae isolates were almost all β-lactamase negative (90.9%). One isolate was β-lactamase negative and ampicillin resistant (BLNAR) by CLSI and four isolates were BLNAR by EUCAST criteria. Susceptibility of isolates was high (≥90.9%) by CLSI breakpoints for all antibiotics tested except trimethoprim/sulfamethoxazole (61.6%). Susceptibility using EUCAST breakpoints was similar for ampicillin (90.9%) and amoxicillin/clavulanic acid (95%) but was low for cefuroxime (oral), where only 10.1% of isolates were susceptible. All S. pneumoniae and H. influenzae isolates were susceptible to the fluoroquinolones by all breakpoints. Susceptibility to ceftriaxone was also 100% for H. influenzae and ≥91% for S. pneumoniae isolates by all breakpoints. The application of different EUCAST breakpoints for low and higher doses for some of the antibiotics (amoxicillin, amoxicillin/clavulanic acid, ampicillin, penicillin, ceftriaxone, clarithromycin, erythromycin, levofloxacin and trimethoprim/sulfamethoxazole) allowed, for the first time in a SOAR study, the effect of raising the dosage on susceptibility to be quantified.

CONCLUSIONS

Antibiotic susceptibility in these respiratory tract pathogens was generally high in Ukraine. These data are important for empirical therapy choices in the treatment of CA-RTIs.