Oral flora of domestic cats in Hong Kong: Identification of antibiotic-resistant strains.

BACKGROUND: As the clinical outcome of bite-associated infection is related to the oral commensals, evaluating their composition and antibiotic susceptibility pattern can provide more information for the antibiotic treatment of wound infections and increase the awareness of the multidrug-resistant bacteria in cat oral flora. AIMS: This study was conducted to identify the various bacterial species in the oral cavity of cats. It aimed to identify the composition of cat oral flora and antibiotic resistant bacterial stains. MATERIALS AND METHODS: Twenty-two cats were sampled for bacterial evaluation. Matrix-assisted laser desorption/ionization time of flight mass spectrometry was used to provide rapid and reliable detection and identification of the bacterial species. Antibiotic susceptibility tests were performed in the identified isolates to determine the antibiotic susceptibility pattern and to detect the multidrug-resistant bacteria in the cat oral cavities. RESULTS: A total of 54 isolates were identified, Pasteurella was the genus most commonly isolated from the oral cavity of cats (19/54, 35.19%), followed by Neisseria spp. (8/54, 14.81%) and Staphylococcus spp. (7/54, 12.96%). Uncommon oral flora were isolated from the samples, including Pasteurella canis, Inquilinus limosus and the Enterobacteriaceae family of Escherichia coli, Klebsiella pneumoniae and Serratia marcescens. Fourteen different multidrug-resistant bacteria were detected, including Pasteurella species (4/14), Bacillus species (2/14), Neisseria species (3/14), Escherichia species (1/14) and Staphylococcus species (4/14). DISCUSSION AND CONCLUSIONS: This study's findings will increase the understanding of the composition of cat oral flora in Hong Kong, which can provide more evidence-based information for the prophylactic treatment of patients with cat bite infections. Moreover, the study identified and detected the antibiotic resistance pattern and multidrug-resistant bacteria in the cat oral cavity, which can help cat owners increase their awareness of maintaining regular oral hygiene for their cats to prevent the spread of pathogens from cats to humans.

Involvement of caspase-4 in IL-1 beta production and pyroptosis in human macrophages during dengue virus infection.

Caspase-4 physically interacts with caspase-1 and is believed to be a proinflammatory caspase that can induce the inflammatory form of programmed cell death (pyroptosis) and the release of mature interleukin (IL)-1ß. However, the function of caspase-4 in dengue virus infection is not yet fully understood. We examined the function of caspase-4 in IL-1ß production and pyroptosis during dengue virus serotype-2 (DENV-2) infection in human macrophages. In this study, DENV-2 infection increased IL-1ß protein level with activated caspase-4 activity. Using primary macrophages, we observed that caspase-4 induces activation of caspase-1 and secretion of IL-1ß in response to DENV-2 infection, without the need for secondary signals to stimulate the assembly of the inflammasome. These findings indicate that the regulation of caspase-1 activity by capsase-4 could represent a unique mechanism. Our data suggest that caspase-4 is upstream of caspase-1 in the pathway that regulates pyroptosis and IL-1ß synthesis in macrophages during DENV-2 infection.