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. 2017 Apr 6;12(4):e0174908. doi: 10.1371/journal.pone.0174908

Fig 1. Spectra obtained by MHA.

Fig 1

A) The spectrum obtained for the pure meropenem (arrived with ice) showed the peaks corresponding to the intact drug (384 ±1 Da) and to its sodium salts (406 ±1 Da; 428 ±1 Da); the spectrum obtained for the carbapenemase-nonproducing reference strain (K. pneumoniae ATCC BAA-1706) showed the same peaks as the pure meropenem, while the 2 carbapenemase-producing reference strains (K. pneumoniae ATCC BAA-1705, blaKPC positive, and K. pneumoniae ATCC BAA-2146, blaNDM positive) gave the peaks corresponding to the meropenem degradation (358 ±1 Da, the decarboxylated product) and to its sodium salts (380 ±1 Da; 402 ±1 Da; 424 ±1 Da). B) Example of spectra obtained for clinical samples tested with pure meropenem arrived with ice: a carbapenemase-nonproducing strain and two carbapenemase-producing strains, one of which (K. pneumoniae No. 1135 strain) showing the peaks corresponding to both the pure meropenem and the degradation products of the drug.