Isolation and characterization of Ochrobactrum anthropi and Ochrobactrum pecoris from caecal content of commercial turkeys.

Two Gram negative, micro-aerophilic, non-motile and non-spore-forming coccoid bacteria were isolated from female turkey caecal samples collected from a slaughterhouse. The biochemical reaction profiles (API 20 E and API 20 NE) typed both strains as Ochrobactrum anthropi. On the basis of 16S rRNA gene and recA gene sequence similarities the strains were identified as O. anthropi and Ochrobactrum pecoris, respectively. Both strains were highly resistant against beta-lactam antibiotics, chloramphenicol and sulphonamides but variable in susceptibility to ciprofloxacin, gentamicin and tetracycline. This is the first time that Ochrobactrum species were isolated from an avian host, i.e. turkey.

Differentiation of Campylobacter species by surface-enhanced laser desorption/ionization-time-of-flight mass spectrometry.

The genus Campylobacter contains several, widespread pathogens causing food-borne diseases of zoonotic nature in humans. In case of outbreaks, the differentiation of closely related Campylobacter is essential for epidemiological studies, which investigate the routes of geographical spread and ways of transmission. Recent advances in mass spectrometry (MS) have shown that matrix-assisted laser desorption/ionization-time-of-flight (MALDI-TOF) MS is a valuable tool for speciation of bacteria such as Campylobacter. Surface-enhanced laser desorption/ionization (SELDI)-TOF-MS is a specific MALDI-TOF application that combines a chip-based chromatographic enrichment of proteins with TOF-MS. This pilot study aims at investigating for the first time whether SELDI-TOF-MS can be applied for discrimination of Campylobacter at the level of species and even strains. Campylobacter type-strains and isolates from different regions were cultured and subsequently subjected to physicochemical lysis. Protein lysates were then applied on CM10 and IMAC30 ProteinChip Array surfaces and analyzed using a PCS 4000 SELDI Protein Chip System (Bio-Rad Laboratories). By comparison of the spectra from Campylobacter jejuni, Campylobacter coli, Campylobacter upsaliensis, and Campylobacter lari, 166 and 160 different protein peaks were observed (p<0.05) using CM10 and IMAC30 chips, respectively. Development of classification trees, comprising 2-4 of these peaks, allows for discrimination of different Campylobacter species and even strains. Moreover, species and strains can be sufficiently separated from each other by hierarchical cluster analysis. Thus, SELDI-TOF-MS is a promising tool to differentiate Campylobacter species and even strains. Species/strain-specific ions observed in addition to well-established markers identified by MALDI-TOF might be of value for future Campylobacter-identifying algorithms. To further clarify the potential advantages of this method, our results have to be validated against several independent test datasets of, preferably, a multitude of prospectively collected different isolates and compared with other typing techniques.