Figure 4. Serum and PMN bactericidal activity in 6 clinical isolates in study of carbapenem-resistant, virulence plasmid–harboring Klebsiella pneumoniae isolates, United States. A–B) The indicated clinical isolates were cultured with 0%, 5%, 25%, or 83% NHS for 1 hour, and recovered viable bacteria were enumerated as both percentages (A) and absolute values (B). Asterisk (*) indicates p<0.05 vs. 0% serum by using a repeated-measures analysis of variance and Dunnett posttest; hash mark (#) indicates p<0.05 vs. ARLG-3254 in 25% or 83% NHS by using a t-test. C–D) Survival of clinical isolates determined following synchronized PMN phagocytosis assays at 30 or 60 min as described. Data are expressed as percentage survival (C) or colony-forming units (D). Results represent the mean (dots) + SD (error bars) of 3 separate experiments. Asterisk (*) indicates p<0.05 as determined by using a repeated-measures analysis of variance and Bonferroni posttest (selected pairs of data) or Kruskal-Wallis test and Dunn posttest for nonparametric analysis of ARLG-4744; hash mark (#) indicates p<0.05 vs. ARLG-3254 for 30 or 60 min in PMN by using a t-test. We conducted statistical analyses by using CFUs. NHS, normal human serum; PMN, polymorphonuclear neutrophils; ST, sequence type.