FIG. 4.
Colony morphology (A), cell-cell autoaggregation (B), phase-contrast microscopy (C), and immunofluorescence microscopy with anti-Ag43 serum (D) of the capsule-producing K. pneumoniae strain C105 containing either (i) pBR322 (control) or (ii) pHHA147 (Ag43+) and the capsule-negative strain C105 NCV containing either (iii) pBR322 (control) or (iv) pHHA147 (Ag43+). The frizzy colony morphology and cell-cell aggregation imparted by Ag43 is prevented by the concomitant surface expression of the K. pneumoniae K35 capsule.