Capsule types of Klebsiella pneumoniae isolated from the genital tract of mares with metritis, extra-genital sites of healthy mares and the genital tract of stallions.

This research investigated the types of Klebsiella pneumoniae, a bacteria, found in the genital tracts of mares with metritis, in healthy mares, and in stallions. The researchers found that heavily encapsulated strains of a type known as K1 are linked with metritis in mares, a condition more common in racing breeds.

Research Method

• The research was done through a survey of K. pneumoniae collected from cervical swabs, feces, and nasal swabs of mares, and from samples from the genital tract of stallions.
• This survey was carried out from 1980 to 1986 in south-western Hokkaido, Japan.

Findings About K1

• K1 was found to be the most common bacteria type in cases of metritis, an inflammation of the uterus, in mares of racing breeds, appearing in 89.8% of cases.
• The same K1 type was also found in 30.0% of the stallions of racing breeds, collected from semen and fossa glandis swabs.
• It was noted that both heavily encapsulated and less heavily encapsulated K1 strains were found in the stallions.
• Mares that were bred to stallions carrying heavily encapsulated strains developed metritis, while those bred to stallions with less heavily encapsulated strains did not.

Findings About K39 and Untypable Strains

• K39 was found only in mares of draft breeds suffering from metritis and was not found in any of the tested mares of the racing breeds.
• Strains that could not be typed (untypable strains) were found in 8.0% of metritis cases in mares of racing breeds and in 36.8% of racing breed stallions.
• Untypable strains were also the most common type found in the feces (90.5%) and nasal swabs (75.0%) of healthy racing breed mares.

Implications

• The research findings suggest that heavily encapsulated strains of K1 are linked with metritis in mares, particularly those of racing breeds. This suggests that racehorse breeders should take this into account when breeding and managing their horses, as breeding mares with stallions carrying heavily encapsulated K1 strains can lead to metritis.
• The finding that K39 is found only in draft mares with metritis, and not in racing breed mares, suggests that this type may be a breed-specific marker or risk factor for metritis.
• The prevalence of untypable strains in healthy racing breed mares warrants further study.