Potential involvement of Campylobacter curvus and Haemophilus parainfluenzae in preterm birth.

A woman presented with prelabour premature preterm rupture of membranes and delivered extremely preterm at 26 weeks by caesarean section. Histopathology of the placenta indicated moderately severe histological chorioamnionitis with dense infiltration of the chorionic plate by neutrophils. Two sets of low and high vaginal swabs were taken from the mother. A set sent for microbiological analysis at the hospital yielded negative results. The second set was analysed employing culture-independent high-throughput sequencing methods and revealed significant infections with Campylobacter curvus and Haemophilus parainfluenzae. This is the first report of C. curvus infection in the female genital tract that has been identified in a woman who delivered preterm. The case supports the need to review the standard culture methods employed for microbial analyses in hospitals.

Identification of disulfide reductases in Campylobacterales: a bioinformatics investigation.

Disulfide reductases of host-colonising bacteria are involved in the expression of virulence factors, resistance to drugs, and elimination of toxic compounds. Large-scale genome analyses of 281 prokaryotes identified CXXC and CXXC-derived motifs in each microorganism. The total number of these motifs showed correlations with genome size and oxygen tolerance of the prokaryotes. Specific bioinformatic analyses served to identify putative disulfide reductases in the Campylobacterales Campylobacter jejuni, Helicobacter pylori, Wolinella succinogenes and Arcobacter butzleri which colonise the gastrointestinal tract of higher animals. Three filters applied to the genomes of these species yielded 35, 25, 28 and 34 genes, respectively, encoding proteins with the characteristics of disulfide reductases. Ten proteins were common to the four species, including four belonging to the thioredoxin system. The presence of thioredoxin reductase activities was detected in the four bacterial species by observing dithiobis-2-nitrobenzoic acid reduction with beta-nicotinamide adenine dinucleotide phosphate as cofactor. Phylogenetic analyses of the thioredoxin reductases TrxB(1) and TrxB(2) of the four Campylobacterales were performed. Their TrxB(1) proteins were more closely related to those of Firmicutes than to the corresponding proteins of other Proteobacteria. The Campylobacterales TrxB(2) proteins were closer to glutathione reductases of other organisms than to their respective TrxB(1) proteins. The phylogenetic features of the Campylobacterales thioredoxin reductases suggested a special role for these enzymes in the physiology of these bacteria.