Non typable-Haemophilus influenzae biofilm formation and acute otitis media

Abstract

BackgroundNon-typable Haemophilus influenzae (NT-Hi) infection is frequently associated with acute otitis media (AOM) treatment failure, recurrence or chronic otitis media. Persistence of otopathogens in a biofilm-structured community was implicated in these situations. Here, we compared biofilm production by H. influenzae strains obtained by culture of middle ear fluid (MEF) from children with AOM treatment failure and by strains isolated from nasopharyngeal (NP) samples from healthy children or those with AOM (first episode or recurrence). We aimed to evaluate an association of clinical signs and in vitro biofilm formation and establish risk factors of carrying a biofilm-producing strain.MethodsWe used a modification of the microtiter plate assay with crystal violet staining to compare biofilm production by 216 H. influenzae strains: 41 in MEF from children with AOM treatment failure (group MEF), 43 in NP samples from healthy children (NP group 1), 88 in NP samples from children with a first AOM episode (NP group 2, n = 43) or recurrent (NP group 3, n = 45) and 44 in NP samples from children with AOM associated with conjunctivitis (NP group 4).ResultsAt all, 106/216 (49%) H. influenzae strains produced biofilm as did 26/43 (60.5%) in NP samples from healthy children. Biofilm production in MEF samples and NP samples did not significantly differ (40.5% vs 60.5%, 55.8%, 56.8% and 31.1% for NP groups 1, 2, 3 and 4, respectively). On multivariate analysis, only presence of conjunctivitis was significantly associated with low biofilm production (OR = 0.3, CI [0.16-0.60], p = 0.001). The ampicillin resistance of H. influenzae produced by penicillin-binding protein modification was significantly associated with low biofilm production (p = 0.029).ConclusionWe found no association of biofilm production and AOM treatment failure or recurrence. Biofilm production was low from H. influenzae strains associated with conjunctivitis-otitis syndrome and from strains with modified penicillin-binding protein.

Trends in antibiotic resistance of Streptococcus pneumoniae and Haemophilus influenzae isolated from nasopharyngeal flora in children with acute otitis media in France before and after 13 valent pneumococcal conjugate vaccine introduction

“…Furthermore, PCV implementation may have led to an additional reduction in prescriptions [ 25 ]. The second hypothesis is more speculative: in our population, most Hi strains now produce biofilms [ 26 ], which allows for resistance to antibiotic treatments without another mechanism of resistance required [ 27 , 28 ].…”

Proteobacteria, extremophiles and unassigned species dominate in a tape-like showerhead biofilm

“…To address the ability of the isolates to form biofilms, a semi-quantitative static model which has been demonstrated to be a reliable and reproducible method for assessing biofilm formation in vitro was used. 13 , 14 , 25 Following the advice and approach of others, 25 a number of formulae (3 in total, see materials and methods and Table 1 ) were used on the raw data to offset variations in culture conditions, methodologies and environmental factors. Of the plate count isolates, only the Cupriavidus sp.…”

Biofilm production by Haemophilus influenzae and Streptococcus pneumoniae isolated from the nasopharynx of children with acute otitis media

“…Biofilm production was evaluated by a modification of the microtiter plate assay with crystal violet (CV) stain as described for NT- Hi [27]. This assay was based on the ability of bacteria to adhere to solid polystyrene surfaces by using biofilm.…”

“…Methods based on PCR techniques have been described, but they cannot discriminate between planktonic and biofilm-growing bacteria [26]. In our previous study, by using a modification of the microtiter plate assay with crystal violet (CV) stain, we found that 49% of H. influenzae strains isolated from children’s nasopharynx produced biofilm [27].…”