Activity of temocillin against ESBL-, AmpC-, and/or KPC-producing Enterobacterales isolated in Poland

Abstract

We evaluated the in vitro effectiveness of temocillin and several commonly used antimicrobials against Enterobacterales bacteria in isolates from Polish patients. We tested 400 isolates: 260 extended-spectrum β-lactamase (ESBL)- and/or ampC β-lactamase (AmpC)-producing isolates; 40 Klebsiella pneumoniae carbapenemase (KPC)-producing isolates; and 100 ESBL-, AmpC-, and KPC-negative isolates. The minimal inhibitory concentrations (MICs) of temocillin and 16 other antimicrobials were determined by reference microdilution. We also determined the activities of fosfomycin and ceftazidime/avibactam in KPC-producing isolates. The antibiotic sensitivities were interpreted according to EUCAST, BSAC, and CLSI criteria. Overall, 91% of the isolates were susceptible to temocillin using the urinary tract infection breakpoint (≤ 32 mg/L), and 61.8% were susceptible using the systemic infection breakpoint (≤ 8 mg/L). Meropenem and imipenem were the most active drugs (MIC50 values of 0.06 and 0.5 mg/L, respectively). Colistin and ertapenem (both MIC50 = 0.12 mg/L) were less active than meropenem or imipenem, but some strains were 77% susceptible to each of them. Among the KPC-producing isolates, 42.5% had MIC values of ≤ 32 mg/L (urinary tract infection breakpoint), but 100% were resistant to temocillin (systemic infection breakpoint). Ceftazidime/avibactam was active against 100% of the KPC-producing isolates, and fosfomycin was active against 40%. The empirical susceptibility rate observed among the urinary isolates suggests that temocillin may be considered as an alternative to carbapenems in the absence of KPC-producing bacteria. With regard to isolates from other sources, temocillin might be useful as a documented therapy agent or an empirical treatment in hospitals with a low prevalence of ESBL/AmpC-producing strains.