Multidrug Resistance Related to Biofilm Formation in Acinetobacter baumannii and Klebsiella pneumoniae Clinical Strains from Different Pulsotypes

Abstract

The emergence of Acinetobacter baumannii and Klebsiella pneumoniae strains in the hospital environment has been associated with the presence of multiple genetic elements, virulence factors and the ability to form biofilms. This study evaluated the biofilm formation ability of clinical and environmental A. baumannii and K. pneumoniae strains, isolated from various sources and presenting different molecular characteristics, resistance profiles and pulsed-field gel electrophoresis patterns. Fifty-three isolates were recovered from 2009 to 2014 in a Brazilian university hospital. Investigation of biofilm formation was performed for 10 strains of each species assessed by an initial adhesion assay, biofilm cell concentration and biofilm biomass, evaluated by quantitative assays in replicates, in three independent experiments. All strains of A. baumannii were able to attach to polystyrene plates, although two strains adhered to a lesser degree than the control. K. pneumoniae strains showed opposite behaviour, where only three strains adhered significantly when compared to the control. Quantitative evaluation revealed that in five A. baumannii and four K. pneumoniae isolates the biomass production could be characterised as moderate. None of the isolates were strong biofilm producers. Our results demonstrate: (1) biofilm formation is a heterogeneous property amongst A. baumannii and K. pneumoniae clinical strains and it was not associated with certain clonal types; (2) no relationship between multidrug resistance and biofilm production was observed; (3) more virulent K. pneumoniae strains tended to present higher production of biofilm.

Association of Antibiotic Resistance, Cell Adherence, and Biofilm Production with the Endemicity of NosocomialKlebsiella pneumoniae

“…Most interesting and intriguing was to find that nonendemic clones produced strong biofilms independent of ESBL production. In agreement with our results are the recent observations by de Campos et al, [ 11 ] who did not find a link between antimicrobial resistance and biofilm production in clinical isolates of K. pneumoniae and A. baumannii . However, our results contrast with other previous studies in which a direct relationship between the antimicrobial resistance and biofilm production has been shown [ 23 – 25 ].…”

“…While it appears that antibiotic resistance coupled to biofilm formation and extracellular fibrillar adhesive appendages have contributed to the global spread of K. pneumoniae and other gram-negative bacilli, the relationship among these factors has not been elucidated [ 11 ]. Recently, the relationship between virulence, multidrug resistance, and biofilm formation in clinical strains of Acinetobacter baumannii and K. pneumoniae was evaluated [ 11 ]. It was found that the ability to form biofilms was not associated with clonal types or multidrug resistance.…”

<em>Acinetobacter baumannii</em> biofilms: effects of physicochemical factors, virulence, antibiotic resistance determinants, gene regulation, and future antimicrobial treatments

“… 21 Environmental isolates collected from patients’ rooms at Federal University of Uberlandia Hospital in Brazil were also reported to produce biofilm. 22 These may suggest that the source of microbial cells may have a great impact on the capacity of the cells to produce biofilm.…”

High Adhesion and Increased Cell Death Contribute to Strong Biofilm Formation in Klebsiella pneumoniae

“…Recently, several studies report the association of antibiotic resistance with biofilm formation in clinical isolates of Klebsiella spp. [11][12][13][14]. Moreover, the role of fimbriae in adhesion and biofilm formation by Klebsiella is also well documented [15,16].…”