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ABSTRACT: Background
To evaluate the in vitro activities of plazomicin and comparator aminoglycosides and elucidate the underlying aminoglycoside resistance mechanisms among carbapenemase-producing K. pneumoniae isolates collected during a nationwide surveillance study in Greek hospitals.Methods
Three hundred single-patient carbapenemase-producing K. pneumoniae isolates were studied, including 200 KPC-, 50 NDM-, 21 VIM-, 14 KPC & VIM-, 12 OXA-48-, two NDM & OXA- and one KPC & OXA-producing isolates. Susceptibility testing was performed by broth microdilution, and minimum inhibitory concentrations (MICs) interpreted per EUCAST breakpoints. Carbapenemase-, aminoglycoside modifying enzyme- and 16S rRNA methylase- encoding genes were detected by PCR.Results
Of 300 isolates tested, 5.7% were pandrug resistant and 29.3% extensively drug resistant. Plazomicin inhibited 87.0% of the isolates at ?2?mg/L, with MIC50/MIC90 of 0.5/4?mg/L. Apramycin (a veterinary aminoglycoside) inhibited 86.7% of the isolates at ?8?mg/L and was the second most active drug after plazomicin, followed by gentamicin (S, 43%; MIC50/MIC90, 4/>?256) and amikacin (S, 18.0%; MIC50/MIC90, 32/128). Twenty-three (7.7%) isolates (16 KPC-, 6 VIM- and one KPC & OXA-48-producers) exhibited MICs ?64?mg/L for plazomicin, and harbored rmtB (n =?22) or armA (n =?1). AAC(6')-?b was the most common aminoglycoside modifying enzyme (84.7%), followed by AAC(3?)-IIa (25.3%), while those two enzymes were co-produced by 21.4% of the isolates.Conclusions
Plazomicin retains activity against most carbapenemase-producing K. pneumoniae isolated from Greek hospitals, with MICs consistently lower than those of the other aminoglycosides, even in the presence of aminoglycoside modifying enzymes. Dissemination of 16S- rRNA methylases in 8% of the isolates is an unwelcome event that needs strict infection control measures and rigorous stewardship interventions.
SUBMITTER: Galani I
PROVIDER: S-EPMC6377745 | biostudies-literature | 2019 Feb
REPOSITORIES: biostudies-literature
BMC infectious diseases 20190215 1
<h4>Background</h4>To evaluate the in vitro activities of plazomicin and comparator aminoglycosides and elucidate the underlying aminoglycoside resistance mechanisms among carbapenemase-producing K. pneumoniae isolates collected during a nationwide surveillance study in Greek hospitals.<h4>Methods</h4>Three hundred single-patient carbapenemase-producing K. pneumoniae isolates were studied, including 200 KPC-, 50 NDM-, 21 VIM-, 14 KPC & VIM-, 12 OXA-48-, two NDM & OXA- and one KPC & OXA-producing ...[more]