ABSTRACTWhile characterizing the intestinal bacterial community of broiler chickens, we detected ε-proteobacterial DNA in the ilea of 3-day-old commercial broiler chicks (J. Lu, U. Idris, B. Harmon, C. Hofacre, J. J. Maurer, and M. D. Lee, Appl. Environ. Microbiol.69:6816-6824, 2003). The sequences exhibited high levels of similarity toCampylobacter jejuniandCampylobacter colisequences, suggesting that chickens can carryCampylobacterat a very young age.Campylobactersp. was detected by PCR in all samples collected from the ilea of chicks that were 3 to 49 days old; however, it was detected only in the cecal contents of chickens that were at least 21 days old. In order to determine whether the presence ofCampylobacterDNA in young chicks was due to ingestion of the bacteria in food or water, we obtained commercial broiler hatching eggs, which were incubated in a research facility until the chicks hatched. DNA sequencing of the amplicons resulting fromCampylobacter-specific 16S PCR performed with the ileal, cecal, and yolk contents of the day-of-hatching chicks revealed thatCampylobacterDNA was present before the chicks consumed food or water. The 16S rRNA sequences exhibited 99% similarity toC. jejuniandC. colisequences and 95 to 98% similarity to sequences of other thermophilicCampylobacterspecies, such asC. lariandC. upsaliensis. The presence ofC. coliDNA was detected by specific PCR in the samples from chicks obtained from a commercial hatchery; however, noCampylobacterwas detected by culturing. In order to determine whether the same strains of bacteria were present in multiple levels of the integrator, we culturedCampylobactersp. from a flock of broiler breeders and their 6-week-old progeny that resided on a commercial broiler farm. The broiler breeders had been given fluoroquinolone antibiotics, and we sought to determine whether the same fluoroquinolone-resistant strain was present in their progeny. The isolates were typed by pulsed-field gel electrophoresis, which confirmed that the parental and progeny flocks contained the same strain of fluoroquinolone-resistantC. coli. These data indicate that resistantC. colican be present in multiple levels of an integrated poultry system and demonstrated that molecular techniques or more sensitive culture methods may be necessary to detect early colonization byCampylobacterin broiler chicks.
Dissemination of Fluoroquinolone-Resistant Campylobacter spp. within an Integrated Commercial Poultry Production System
