RESUMEN
Staphylococcus pseudintermedius is a commensal and an opportunistic pathogen in dogs, and is also an opportunistic pathogen in humans. Here we report about a case of bacteraemia with a fatal outcome in a 77-year-old co-morbid male likely caused by a S. pseudintermedius and the investigation into the possible transmission from the two dogs in the patient's household. The two dogs carried the same S. pseudintermedius strain, but this dog strain was unrelated to the strain from the patient. In contrast to the patient strain, the dog strain showed reduced susceptibility to several antibiotics and both dogs had received antibiotic treatment prior to sampling. So, it is conceivable that these treatments can have eliminated the patient's strain between the transmission event and the dog sampling. It is also worth noting that the patient strain was positive for the expA gene, which encodes an exfoliative toxin closely related to the S. aureus exfoliative toxin B. This toxin has been linked to canine pyoderma, but its effect on humans remains unknown. Transmission of S. pseudintermedius was confirmed in the household between the dogs. However, we could not verify that the dogs were the source for the S. pseudintermedius in the patient.
RESUMEN
The aim of the study was to use culture, qPCR and seM sequencing to map Streptococcus equi subspec. equi (S.equi) isolates in long term carrier animals. A strangles outbreak affecting 41 Icelandic horses was followed to determine strangles free status using nasal and/or guttural pouch lavages collected serially on eleven separate occasions over 13 months. Ten persistent carriers, of which eight had repeated culture positive samples for S. equi, were selected for the study. Of 115 samples collected, 61 were S. equi positive on qPCR; from which 32 were also culture positive. Amplification of parts of the gene encoding the M-protein seM was performed on isolated colony material (n = 32) or, where only PCR product was obtained, directly on the DNA sample (n = 29) with a nested amplification approach. The seM sequence could be determined for six of the 29 samples that were solely qPCR positive. The outbreak was due to a S. equi strain of seM type 72. Three months after initial sampling isolates from two horses had seM gene sequences with one amino acid change. After six months S. equi with truncated seM genes were found in two horses; one variant in a single horse once, and in the other horse a variant that persisted and that was later identified in two additional horses. Non- mucoid S. equi colonies were found in two horses. Importantly, after acute strangles outbreaks many horses not only remain persistently qPCR positive for S. equi but are also intermittently culture positive.
