Abstract
Background:
Klebsiella pneumoniae is an important human and animal pathogen that causes a wide spectrum of infections.

Aim:
This study attempted to isolate and characterize K. pneumoniae from the respiratory tract of Aceh cattle.

Methods:
Pneumonic lung tissue and tracheal swabs were collected from a slaughterhouse in Banda Aceh city and the district of Aceh Besar. The isolates were identified using biochemical tests (indole, methyl red, Voges–Proskauer, sulfide indole motility, and citrate utilization) and polymerase chain reaction (PCR) to amplify the rpoB gene. The hypermucoviscous phenotype was determined by the string test. The presence of the capsule cluster genes MagA, k2A, and wzx-K5 was used to characterize the capsular serotypes K1, K2, and K5, respectively.

Results:
A total of 54 K. Pneumoniae isolates were obtained from 38 of 61 (62.3%) cattle. Twenty-two isolates (40.7%) were positive for the K1 genes, 16 isolates (29.6%) were positive for the K2 genes, and 16 isolates (29.6%) were negative for K1, K2, and K5 genes and classified into non-K1/K2/K5. The rmpA gene was detected in 62.5% and 63.6% of K2 and K1 isolates, respectively. mrkD and ent genes were detected in all isolates, and ytbs was detected in 72.7% and 75% of K1 and K2 isolates, respectively.

Conclusion:
Numerous K. pneumoniae serotypes were involved in infecting Aceh cattle, and serotype K1 had the highest prevalence.

Key words: Aceh cattle, Capsular serotype, Klebsiella pneumoniae, Pneumonic lung, Virulence genes