Comparison of virulence genes and structural differences of multiple Campylobacter genomes. Campylobacter

Campylobacter. Members of this genus are one of the most common causes of bacterial gastroenteritis (campylobacteriosis). Usually the symptoms are abdominal pain, fever, diarrhea, and cramps, but the illness can sometimes be fatal and some infected individuals develop a syndrome (Guillain-Barre) in which the nerves connecting the spinal cord to the brain are damaged. C. jejuni is the main cause of campylobacteriosis, but other species can also cause infection, including C. coli, C. upsaliensis, and C. lari. Comparison of these organisms helped elucidate some potential virulence mechanisms. C. jejuni strain RM1221, isolated from a chicken carcass, was compared to the previously sequenced C. jejuni strain NCTC 11168. Four large integrated elements were responsible for the major differences between the genomes of these two strains. The C. coli RM2228 genome also exhibited a great deal of synteny with the genome of C. jejuni strain RM1221, however, C. lari, and C. upsaliensis displayed little synteny with RM1221. Differences in homopolymeric tracts were found during the comparison, which may affect phase variation in some virulence genes. C. upsaliensis shows the greatest variation in these tracts. There are also variations in lipooligosaccharide genes and other genes that contribute to pathogenesis. A novel virulence locus, licABCD, was discovered in RM3195, which has similarity to genes involved in choline metabolism. Some of these genes also affect cell wall molecules such as lipooligosaccharide and teichoic acids that are involved in attachment to host cells and are found in Haemophilus influenzae, Neisseria sp., and Streptococcus pneumoniae. There were also differences in antibiotic resistance mechanisms which may reflect antibiotic usage in the host organism these microbes normally inhabit.