engleski

Biofilm-forming ability, antimicrobial susceptibility and proteomic phenotypes of Klebsiella pneumoniae strains isolated on a turkey farm

Klebsiella pneumoniae is often recognized as a multidrug resistant species which represents a growing clinical problem in human and veterinary medicine. Although it is usually an environmental contaminant, it has an important role in spreading antimicrobial resistance genes to clinically important species. We investigated the biofilm-forming ability, antimicrobial susceptibility and proteomic phenotypes of thirteen K. pneumoniae strains isolated on a turkey farm. The study included strains isolated from six flocks during the routine health monitoring. Ten strains were isolated from the birds, two from the cardboard transport boxes of 1-day old poults, and one from the feeding system. The birds were submitted to necropsy and sampled upon indication, the feeding system tray was swabbed, and the transport boxes were sampled by scraping and collecting the feces. Bacterial identification was based on morphology, biochemical properties, and Bruker Microflex LT MALDI-TOF Mass Spectrometry. Biofilm- forming ability was tested using quantitative adherence assay on microtiter plates. Strains were tested in quadruplicate and the assay was performed twice. Antimicrobial susceptibility was determined using disk diffusion assay on Mueller-Hinton agar. The assay was performed with fourteen antibiotics and the inhibition diameters were interpreted according to EUCAST standards. The proteomic phenotypes of the strains were compared using principal component analysis and the minimum spanning tree generated with MALDI Biotyper. All strains were multidrug resistant, with the highest resistance rates to amoxicillin and lincomycin (100%), and enrofloxacin, flumequine and norfloxacin (76, 92%). The proteomic analysis showed nine lineages, with the cut-off value set at a 100-distance level. There was no significant link between the tissue and flock of origin with the proteomic similarity of the strains. The results of the biofilm quantification showed that 23, 08% and 76, 92% of the investigated strains were moderate and strong biofilm producers, respectively. Although the farm is successfully implementing the antibiotic reduction strategy, the detected levels of multidrug resistance were high, while the biofilm-forming ability of the strains additionally reduces the efficacy of antimicrobials and disinfectants. The results confirm the important role of K. pneumoniae as a reservoir of resistance genes and indicate a need for continuous surveillance.

Klebsiella pneumoniae ; turkey ; MALDI-TOF MS ; disk diffusion ; biofilm ; resistance ; antibiotic

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