“…Some strains of Providencia alcalifaciens, but no strains of Providencia rettgeri or Providencia stuartii, are invasive in human cell lines (Albert et al, 1995;Janda et al, 1998;Sobreira et al, 2001;Maszewska et al, 2010). Strains of Providencia alcalifaciens isolated from diarrheal samples are able to invade several cultured mammalian cells in vitro, e.g., INT-407, HEp-2, HeLa, Vero, and Caco-2 (Guth and Perrella, 1996;Magalhaes et al, 1996;Janda et al, 1998;Murata et al, 2001;Maszewska et al, 2010). The pathogenicity of Providencia rettgeri against medflys, determined by assessing the effect of the bacteria on medfly egg hatching and development, has also been reported (Msaad Guerfali et al, 2018).…”