CONICET | Buscador de Institutos y Recursos Humanos

INTRODUCTION: Chlamydiae are obligate intracellular pathogens widely distributed in nature. Most of the species included in the Chlamydiaceae family infect humans and animals, causing chronic or acute pathologies. Spheniscus magellanicus is the most abundant penguin of this genre and nests in the coast and islands of Argentina?s Patagonia. Reports on avian chlamydiosis in penguins are rare and often assumed to be caused by Chlamydia psittaci.OBJECTIVE: The aim of this study was to investigate the presence of Chlamydiaceae spp., and C. psittaci in particular, in cloacal samples of Spheniscus magellanicus penguins from Patagonia, Argentina.MATERIALS AND METHODS: Cloacal swabs from penguins were collected, conserved in SPG and included in this study during 2014 and 2015. DNA extraction was performed using a commercial kit according to manufacturer´s instructions. Each sample was tested first for the presence of Chlamydiaceae spp. using a real-time Polymerase Chain Reaction (qPCR) (1). On each Chlamydiaceae-positive sample, a specific qPCR were conducted targeting C. psittaci ompA gene (1). Samples Chlamydiaceae spp. positive but C. psittaci negative, were further analyzed by 16S-23S PCR according to Sachse et al. 2014 (2). In order to identify the species involved, 16S-23S PCR products were sequenced. Cell culture was attempted on Chlamydiaceae spp. positive samples on LLCMK2 cell line according to Sachse et al. 2014 (2).RESULTS: A total of 102 cloacal swabs were included in this study, 74 collected during 2014 and 28 in 2015. All penguins were in good health condition at sampling time. A total of 33 cloacal samples out of the 102 were positive for Chlamydiaceae qPCR (32.3%), 24 were detected in samples collected in 2014 (32.4%) and nine were detected in samples collected in 2015 (32.1%). C. psittaci was not detected by qPCR in any of the Chlamydiaceae qPCR positive samples. Cell culture was attempted unsuccessfully on the 33 Chlamydiaceae spp. positive samples. In one sample a 16S-23S PCR product was obtained and sequenced. The analysis revealed a novel Chlamydia-like bacterium related to a previously found in faecal specimens from seabirds from the Bering Sea (3). DISCUSSION: These results show the presence of Chlamydiaceae spp. but not C. psittaci in cloacal samples from penguins. The fact that we could not establish the species involved in 32 Chlamydiaceae positive samples could be due to low DNA content in the samples, or to the existence of a still unknown species. Moreover, Chlamydia excretion is known to be low and intermittent in asymptomatic birds, perhaps also contributing to low DNA content. Also, Chlamydia-like DNA could be degraded in this type of samples because it may come from the environment (amoeba) or from the penguin?s diet (fish). CONCLUSIONS: This work demonstrates a high frequency (32.3%) of Chlamydiaceae spp. in samples from Spheniscus magellanicus collected over a two year period in Patagonia, Argentina. Zoonotic relevance of Chlamydiaceae spp. found in this study among asymptomatic penguins is still unknown and requires further investigation.