Otitis media pathogens – A life entrapped in biofilm communities

Abstract

Otitis media is a group of inflammatory diseases of the middle ear with great impact on children worldwide. The most common reported bacterial pathogens are Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis. Over the last years, the role of biofilms formed by otopathogens that contribute to otitis media recurrence and chronicity has been established. An improved understanding of the properties of biofilms formed by these bacteria, which factors influence them, and how these affect the host inflammatory response is important for the development of novel strategies for the treatment of otitis media. This review focuses on the biofilm nature that the most prevalent otopathogens adopt in otitis media infections. In addition, new treatment approaches targeting biofilms are highlighted.

Understanding tolerance to cell wall–active antibiotics

“…234 tolerance for Gram-negatives, though case studies suggest instances of similar unexplained treatment failure despite the organism's in vitro susceptibility to antibiotics. 249,261,272 Conversely, some studies have failed to show a clear correlation between tolerance and clinical outcomes; however, these studies are difficult to interpret due to their use of several antibiotics and the aforementioned problems with tolerance definitions and measurements. Mortality of a pediatric population with S. aureus bacteremia correlated more strongly with comorbidities than with tolerance (defined as MBC/MIC >10), 212 but these infections were treated with combination therapy.…”

“…As is apparent from these examples, most clinical studies on tolerance have focused on the classical Gram‐positive model organisms of tolerance research, namely, members of the genera Staphylococcus and Streptococcus . Much less is known about the clinical significance of tolerance for Gram‐negatives, though case studies suggest instances of similar unexplained treatment failure despite the organism's in vitro susceptibility to antibiotics 249,261,272 …”

“…Much less is known about the clinical significance of tolerance for Gram‐negatives, though case studies suggest instances of similar unexplained treatment failure despite the organism's in vitro susceptibility to antibiotics. 249 , 261 , 272 …”

Clinical Relevance and Molecular Pathogenesis of the Emerging Serotypes 22F and 33F of Streptococcus pneumoniae in Spain

“…For instance, serotypes 11A and 35B, which are serotypes frequently associated to multidrug resistance, are good biofilm formers (Domenech et al, 2015). Biofilm formation is a critical aspect from the pathogenesis perspective because S. pneumoniae has been reported to form biofilms in the upper respiratory tract (Wu et al, 2017;Iverson et al, 2019;Silva and Sillankorva, 2019) and nasopharyngeal colonization is the initial step in this process and the prerequisite for developing IPD (Bogaert et al, 2004). Interestingly, active infection is also associated to pneumococcal biofilms in meningitis by binding to brain microvascular endothelial cells and in persistent respiratory infection affecting patients with cystic fibrosis or chronic obstructive pulmonary disease (COPD) (Orihuela et al, 2009;Vidal et al, 2013;Vandevelde et al, 2014;Dennis et al, 2018).…”

In vitro enhancement of ciprofloxacin, tobramycin, and nystatin activity by irradiated aqueous garlic extract against multidrug-resistant pathogens causing otitis media

“…The most common cause of OM is fluid accumulation behind the eardrum because of eustachian tube dysfunction [4]. This leads to the development and accumulation of potentially pathogenic bacteria, fungi, yeasts and viruses in the fluid [5], resulting in recurrent and aggressive reappearance of OM infections. Misuse of antimicrobial agents resulted in the development of multidrug-resistant (MDR) strains, leading to health and economic issues [6].…”