Using multiple colours and fontfaces for axes labels in ggplot

customAxis.R

library(ggplot2)

fakedata = data.frame(
    Bacteria = c("G. vaginalis", "BVAB", "L. crispatus"),
    Count = log10(rlnorm(3*100, 13.5))
)

#create functions to map fontface and colour to bacteria category
#just using sapply
fontFaceFunction = function(bacteriaList)
    sapply(bacteriaList,  USE.NAMES = F,
     function(x)
      if (x == "BVAB") return("plain")
        else return("italic")
    )

#sapply and switch    
fontColourFunction = function(bacteriaList)
    sapply(bacteriaList,  USE.NAMES = F,
     switch, BVAB = "red", 'L. crispatus' = "blue", "black")


ggplot(data = fakedata, aes(x = Bacteria, y = Count)) +
  geom_boxplot() +
  scale_y_continuous(expression(paste("log"[10], "(Count)",sep = "")))  +
  scale_x_discrete("") +
  theme(
    text = element_text(family = "Times", size = 20),
    axis.text.x = element_text(
      angle = 45, hjust = 1, 
      face = fontFaceFunction(levels(fakedata$Bacteria)), 
      colour = fontColourFunction(levels(fakedata$Bacteria))
    )
  )