A eukaryotic-type signalling system of Pseudomonas aeruginosa contributes to oxidative stress resistance, intracellular survival and virulence

Table 2 Production of virulence factors by PAO1 and ΔpppA-ppk A and MIC profiles

	Strain
	PAO1			Δ pppA - ppk A
Virulence factor	24 h	48 h	72 h	24 h	48 h	72 h
elastases - elastine degradation	+	+	+	+	+	+
elastases - casein degradation			+			+
pyocyanin	+	+	+	+	+	+
pyoverdine (OD₄₀₅/OD₆₀₀)^a	0.68 (± 0.032)			0.39 (± 0.054)
phospholipase C	+			+
swarming motility	+			+
swimming motility	+			+
twitching motility			+			+
alginate		+			+
MIC (μg•ml ^-1 ) ^b	PAO1			Δ *pppA* - *ppk* A
chloramphenicol	25			55
carbenicillin	35			75

+ sign indicates positive reaction or manifestation
^a The pyoverdine values are expressed as OD₄₀₅ values of culture supernatants normalized to cell density at OD₆₀₀. Averages based on three independent assays are presented. The numbers in the parentheses represents standard errors of the means. The differences between the mutant and wild-type strain are statistically significant (P < 0.05).
^b The data are representative of four replicates.

ISSN: 1471-2164