|Miller, William - Bill|
Submitted to: Applied and Environmental Microbiology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 12/12/2006
Publication Date: 2/10/2007
Citation: Chan, K., Miller, W.G., Mandrell, R.E., Kathariou, S. 2007. Association of erythromycin susceptibility and absence of intervening sequences in 23s ribosomal rna genes of campylobacter coli isolated from turkeys.. Applied and Environmental Microbiology. 73(4)1208-1214 Interpretive Summary: Campylobacter species are the primary cause of human bacterial gastroenteritis in the world. Therefore, drug resistance in this pathogen is of concern as antibiotics used previously to treat Campylobacter infections can no longer be used. As Campylobacter becomes resistant to an increasing number of antibiotics, the options for clinical treatment diminish greatly. The antibiotic erythromycin is currently the drug of choice for treating Campylobacter infections. Predictably, the prevalence of erythromycin resistance in this bacterium is increasing. Erythromycin resistance is due to a well-characterized mutation linked often to an inserted segment of DNA. This study found that erythromycin resistance is prevalent in Campylobacter coli but not in C. coli strains that originate from turkeys and belong to a peculiar group of C. coli/C. jejuni hybrids.
Technical Abstract: Certain Campylobacter strains have been found to harbor a transcribed intervening sequence (IVS) in at least one copy of the 23S ribosomal RNA gene. Following transcription, the IVS is excised, leading to fragmentation of the 23S rRNA. The origin and possible functions of the IVS are unknown. Furthermore, the distribution of IVS-harboring strains within Campylobacter populations is poorly understood. In this study, 83 Campylobacter coli turkey strains, which were subtyped recently by multilocus sequence typing (MLST), were characterized in terms of their IVS content and antibiotic susceptibility. Fifty-eight strains were found to contain IVSs in all three 23S rRNA genes; only one of these strains was susceptible to erythromycin. In the other 25 strains, IVSs were absent in at least one of the three 23S rRNA genes. All of these 25 strains were susceptible to erythromycin and, according to an MLST study, they belong to a cluster of strains containing the C. jejuni aspA103 allele. Natural transformation showed that the IVS and erythromycin resistance determinant could be transferred simultaneously.