The results of the radial assays were confirmed using liquid broth assays for antimicrobial activity, and showed that lysozyme and β defensin-2 could act synergistically against S. pneumoniae 6B.
These results were confirmed using the liquid broth assay and additionally showed that β defensin-2 had a potent, dose-dependent effect on the growth of S. pneumoniae, even at concentrations as low as 2.5 μg/ml.
Susceptibilities were determined by automated microdilution broth testing (Neg/Urine Combo panel, Dade Behring Inc .. Resistance to imipenem and meropenem was confirmed by using Kirby-Bauer disk diffusion, according to the National Council for Clinical Laboratory Standards (NCCLS) guidelines.
Identification was confirmed by using the API 32GN system (bioMérieux, Marcy-l'Etoile, France). A. baumannii strains were also tested for the ability to grow at 44°C in Trypticase soy broth (Oxoid, Unipath Ltd ,Basingstoke, UK).
Oxacillin susceptibility of the isolates was confirmed by broth microdilution (5 ) with plates read manually.
The antimicrobial susceptibility profile of Kp13 was confirmed by broth microdilution.
Linezolid resistance was confirmed at the Centers for Disease Control and Prevention CDCC, Atlanta, GA, USA) by use of the broth-dilution method; the MIC was >16 µg/mL for all isolates tested.
After species identification was confirmed, MICs were determined by reference broth microdilution method according to Clinical and Laboratory Standards Institute guidelines (11 ).
Isolates were confirmed as MTBC using the BACTEC® para-nitro-acetyl amino-hydroxy-propiophenone (NAP) susceptibility method [ 23] after 4 weeks and stored at – 80 °C in 7H9 broth supplemented with OADC and glycerol for future analysis.
