Morphological and adhesive properties of Klebsiella pneumoniae biofilms

Abstract

<jats:p>Background and Aim: The study of biofilm-forming ability of Gram-negative microflora has great practical importance for assessing the effectiveness of antibiotic therapy and finding new ways to diagnose and inhibit the growth of biofilms. This is because poor penetration of antibacterial drugs into the biofilm can lead to the selection of resistant strains and has a consequence evident by the occurrence of relapse of infection in animals. This study aimed to evaluate morphological and densitometric indicators of biofilm formation as well as adhesive properties of Klebsiella pneumoniae. Materials and Methods: K. pneumoniae was cultured at 37°C for 2-144 h in vitro. The specimens for optical microscopy were prepared by fixation with a 1:1 alcohol-ether mixture for 10 min and stained with a 0.5% solution of gentian violet for 2 min, and the optical density index was evaluated at a wavelength of 490 nm. Further, the adhesive properties of the microorganisms were determined at a concentration of 1 billion/ml and a suspension of ram erythrocytes at a concentration of 100 million/ml when cultured at 37°C for 24 h. Blood smears were prepared and stained with 0.5% gentian violet. Results: K. pneumonia cultured at 37°C after 24 h on the meat peptone agar formed large, convex, mucous, and white colonies (d=3.0-6.0 mm). With the growth in the meat and peptone broth, uniform turbidity of the medium was observed. Analyzing the optical density indices (density, D), it was found that K. pneumoniae were good producers of biofilms (D=0.528±0.31). Data for indicators of adhesive properties of K. pneumoniae were as follows: Average adhesion index, 4.56±0.14; adhesion coefficient, 1.07±0.52; and adhesion index, 4.26±0.07. The studied bacteria had high adhesive activity. A direct correlation dependence (R=0.94) of the optical density of biofilms (D≥0.514-0.551) and AAI (4.15±0.28-4.76±0.75) was established. Conclusion: This study has demonstrated that K. pneumoniae had high adhesive activity, was strong producer of biofilms, and the optical density of the sample exceeded the optical density of the control by more than 4 times.</jats:p>

Morphological characteristics of Candida albicans, Candida krusei, Candida guilliermondii, and Candida glabrata biofilms, and response to farnesol

“…Evidence is accumulating to support the contention that they are integral “superorganisms,” leading a social way of life. Biofilms are a key factor that ensures the preservation of many species [ 1 ]. In the external environment, about 99.9% of all microorganisms are able to form biofilms.…”

First evidence of Klebsiella pneumoniae infection in Aceh cattle: Pathomorphology and antigenic distribution in the lungs

“…The polysaccharide capsule is also important because it favors the attachment to the cell surface and the formation of biofilms [ 6 - 9 ]. In addition, lipopolysaccharides (LPSs) mediate the resistance to complement-mediated and neutrophil-mediated bactericidal activity, as well as the resistance to multiple antibiotics activity [ 9 , 10 ].…”

“…The polysaccharide capsule is also important because it favors the attachment to the cell surface and the formation of biofilms [6][7][8][9]. In addition, lipopolysaccharides (LPSs) mediate the resistance to complement-mediated and neutrophil-mediated bactericidal activity, as well as the resistance to multiple antibiotics activity [9,10]. K. pneumoniae is considered one of the most important pathogens in public health because they are animal-borne bacterial pathogens (zoonoses) [1].…”

Effects of farnesol and lyticase on the formation of Candida albicans biofilm

“…is a function of adhesiveness, invasiveness, hydrolase production, and dimorphic switching (i.e., the morphological transition from yeast form to a mycelial form). Yeast morphology is required for dissemination, and mycelial morphology is needed for invasion [5][6][7]. The transcriptional control of adhesion, formation of biofilms, filamentation and production of extracellular polymeric substances, and ability to interact with other species in biofilms in vivo determine virulence, protection from immune response, and fungicidal drug resistance [8,9].…”