FIG 1.

Representative chromatograms of the peptidoglycan composition and percent cross-linking of wild-type A. baumannii ATCC 17978 and ATCC 17978 overexpressing OXA-23. Overnight cultures were diluted to an OD₆₀₀ of 0.02 and supplemented with 2 mM IPTG. Cultures were grown shaking at 37°C to an OD₆₀₀ of 0.8, and then cells were pelleted by centrifugation. Whole peptidoglycan was purified and processed as described by Schaub and Dillard (36). Peptidoglycan was subjected to high performance liquid chromatography (HPLC) separation and LC-MS identification in triplicate. The solid bars to the left of the chromatograms denote 0.25 AU (absorbance units). Muropeptides associated with the identified fractions are listed in Table S2 in the supplemental material.