Infective endocarditis caused by Enterobacteriaceae: phenotypic and molecular characterization of Escherichia coli and Klebsiella pneumoniae in Rio de Janeiro, Brazil

Abstract

The etiological agent for infective endocarditis (IE), a life-threatening disease, is usually gram-positive bacteria. However, gram-negative bacteria can rarely cause IE and 4% of cases are associated with morbidity and mortality. This study aimed to characterize Escherichia coli and Klebsiella pneumoniae isolates from the blood of patients with IE. The characteristics of blood isolates were compared with those of urinary isolates from patients with urinary tract infections (UTIs). The results of this study revealed that K. pneumoniae isolates from patients with IE were phylogenetically related to those from patients with UTI. Additionally, the resistance phenotype, resistance gene, virulence gene, and plasmid profiles were similar between the blood and urinary isolates. The isolates belonging to the sequence types (STs) 76, 36, 101 (K. pneumoniae), and 69 (E. coli) are reported to be associated with drug resistance. The Enterobacteriaceae isolates from patients with IE did not produce extended-spectrum β-lactamase or carbapenemase. Additionally, this study investigated the virulence phenotype, biofilm formation ability, and the ability to adhere to the epithelial cells in vitro of the isolates. The isolates from patients with IE exhibited weaker biofilm formation ability than the urinary isolates. All isolates from patients with IE could adhere to the renal epithelial cells. However, three isolates from patients with UTIs could not adhere to the epithelial cells. The closely related K. pneumoniae isolates (648, KP1, KP2, KP3, and KP4) could not form biofilms or adhere to the epithelial cells. In summary, the molecular analysis revealed that the genetic characteristics of IE-causing K. pneumoniae and E. coli were similar to those of UTI-causing isolates. These isolates belonged to the STs that are considered treatable. Genetically similar isolates did not exhibit the same virulence phenotype. Thus, these non-hypervirulent clones must be monitored as they can cause complex infections in susceptible hosts.

Trends of Infective Endocarditis at Two Teaching Hospitals: A 12-Year Retrospective Cohort Study in Rio de Janeiro, Brazil

“…The Enterobacteriaceae family is a rare cause of IE, and it was identified in 9% of patients in this cohort. In a previous publication, it was shown that the molecular characteristics of Escherichia coli and Klebsiella pneumoniae isolated from the blood of patients with IE were similar to those isolated from urine; therefore, urinary tract infections should be monitored as a source of bacteremia and IE [ 27 ].…”

ANTIMICROBIAL AND ANTIBIOFILM PROPERTIES OF Combretum platypetalum subsp. oatesii (Rolfe) Exell (Combretaceae) EXTRACTS

“…However, bio-guided or structure-directed isolation will corroborate these findings. The results were also analyzed by a supervised multivariate classification and pattern recognition (Figure 3) output from partial least squares (PLS) at a P-value of 0.003 and a non-supervised principal component Among the bacterial species, the antimicrobial activity against K. pneumoniae is a significant finding because of the rise in isolates producing beta-lactamase and carbapenemase [37]. C. platypetalum was more efficacious against fungi than bacteria, with the MIC for most fungi averaging at 0.0156 mg/mL and the best fungicidal concentration of 0.063 mg/mL observed in the ethyl acetate extract of the maceration extraction method against C. neoformans and C. glabrata, respectively (Tables 1 and 2).…”