Abstract: |
The primary objectives were to isolate and identify Klebsiella pneumoniae (K. pneumoniae),
and determine the antimicrobial resistance patterns and biofilm formation abilities of the isolates.
Additionally, the study aimed to investigate the antimicrobial and anti-biofilm effects of cinnamon
oil against K. pneumoniae isolates. A cross-sectional study was conducted from March 2022 to
April 2023 to collect 200 samples (including 156 nasal swabs and 44 lung specimens) from pneumonic
sheep and goats admitted to the Veterinary Teaching Hospital of Zagazig University, Egypt.
K. pneumoniae was isolated from a total of 72 (36%) samples, with 53 (73.6%) isolates recovered from
nasal swabs and 19 (26.4%) from lung samples. Among the samples, 52 (36.9%) were from sheep and
20 (33.9%) were from goats. Antimicrobial susceptibility testing of the 72 K. pneumoniae isolates to
18 antimicrobials revealed that all isolates were resistant to ampicillin, amoxicillin/clavulanic acid, cefotaxime,
ceftriaxone, tetracycline, colistin, fosfomycin, and trimethoprim/sulphamethoxazole. None
of the isolates were resistant to amikacin, imipenem, and norfloxacin. Multidrug resistance (MDR)
was observed in all K. pneumoniae isolates recovered from sheep and goats. The average MAR index
was 0.71, ranging from 0.50 to 0.83. Regarding biofilm formation, among the K. pneumoniae isolates
with a high MAR index (n = 30), 10% exhibited strong formation, 40% showed moderate formation,
43.3% displayed weak formation, and 6.7% did not form biofilms. Additionally, the biofilm-forming
genes treC and fimA were present in all 28 biofilm-forming K. pneumoniae isolates, while the mrkA
gene was detected in 15 (53.6%) of the 28 isolates. MDR K. pneumoniae isolates with strong biofilm
formation abilities were treated with cinnamon oil at varying concentrations (100%, 75%, 50%, and
25%). This treatment resulted in inhibition zone diameters ranging from 35 to 45 mm. Cinnamon
oil exhibited lower minimum inhibitory concentration and minimum bactericidal concentration
values compared to norfloxacin for all isolates. Additionally, cinnamon oil significantly reduced the
expression of biofilm-associated genes (treC, fimA, and mrkA) when compared to isolates treated with
norfloxacin or untreated. In conclusion, this study identified a high level of MDR K. pneumoniae
with strong and moderate biofilm formation abilities in pneumonic sheep and goats in Sharika
Governorate, Egypt. Although cinnamon oil demonstrated potential antibacterial and anti-biofilm
properties against K. pneumoniae, further research is required to investigate its effectiveness in treating
K. pneumoniae infections in pneumonic sheep and goats.
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