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

Molecular characteristics and biofilm formation capacity of nontypeable Haemophilus influenza strains isolated from lower respiratory tract in children

With the widespread introduction of the Hib conjugate vaccine, Nontypeable Haemophilus influenzae (NTHi) has emerged as the predominant strain globally. NTHi presents a significant challenge as a causative agent of chronic clinical infections due to its high rates of drug resistance and biofilm formation. While current research on NTHi biofilms in children has primarily focused on upper respiratory diseases, investigations into lower respiratory sources remain limited. In this study, we collected 54 clinical strains of lower respiratory tract origin from children. Molecular information and drug resistance features were obtained through whole gene sequencing and the disk diffusion method, respectively. Additionally, an in vitro biofilm model was established. All clinical strains were identified as NTHi and demonstrated the ability to form biofilms in vitro. Based on scanning electron microscopy and crystal violet staining, the strains were categorized into weak and strong biofilm-forming groups. We explored the correlation between biofilm formation ability and drug resistance patterns, as well as clinical characteristics. Stronger biofilm formation was associated with a longer cough duration and a higher proportion of abnormal lung imaging findings. Frequent intake of β-lactam antibiotics might be associated with strong biofilm formation. While a complementary relationship between biofilm-forming capacity and drug resistance may exist, further comprehensive studies are warranted. This study confirms the in vitro biofilm formation of clinical NTHi strains and establishes correlations with clinical characteristics, offering valuable insights for combating NTHi infections.

Bacteriological Profile of Chronic Rhinosinusitis and Adenotonsillitis: Evaluating the Role of Biofilm Production and Multidrug Resistance

There is significant evidence that the etiology of chronic otorhinolaryngology infections such as chronic rhinosinusitis, adenotonsillitis, and otitis media depends on biofilms. As biofilm-forming bacteria can be resistant to the immune system, antibiotics, and other treatments, biofilm infections are often chronic. To identify the genus and species of the clinical isolates obtained from the swabs collected from the patients with chronic infections of the nasal and paranasal sinus, nasopharynx, and oropharynx and to evaluate phenotypic and genotypic methods for the detection of biofilms and antimicrobial resistance among the isolated organisms. A total of 100 patients with chronic rhinosinusitis and adenotonsillitis participated in this study. Various clinical samples from the nasal cavity, nasopharynx, and oropharynx were obtained and subjected to microbiological analysis and biofilm-forming capacity by three methods: tube methods, Congo red staining, and microtiter plate method. The various specific genes were amplified by polymerase chain reaction. The amplified gene products were separated by gel electrophoresis. This was a prospective cohort study conducted on a total of 100 patients with chronic rhinosinusitis and adenotonsillitis. The age of the study participants was between 7 and 53 years with a mean age of 29.22 ± 15.03. This study included 54 (54%) nasal tissue samples and 46 (46%) adenotonsillar tissue. The frequently cultured organisms are coagulase-negative staphylococci (17%), E. coli (10%), Citrobacter (10%), and Klebsiella (7%). Staphylococcus aureus (4), and Methicillin-resistant Staphylococcus aureus (3) produced strong biofilm. Acenobacter (3), Citrobacter (4), and E. coli (4) showed moderate biofilm production. Coagulase-negative Staphylococcus aureus (11), E. coli (6), and Klebsiella (7) showed weak biofilm formation. Citrobacter (6), and Coagulase negative Staphylococcus aureus (6) were negative for biofilm production. Staphylococcus aureus expressed mecA gene (3) and Panton-Valentine Leukocidin gene (2), Pseudomonas expressed mucA gene (2), Citrobacter expressed blaCARB-2 (4) qnrA gene (2), E. coli expressed bla SHV (2) and bla TEM1 gene (2) and Klebsiella expressed Kfu (2) and uge (1). Acenobacter was negative for blaIMP1, blaVIM2 genes. This study adds to the information on the common pathogens-forming biofilms in various nasal pathologies and adenotonsillitis. The knowledge that a particular organism has a higher biofilm-forming capacity will help to sensitize the physician that factors such as biofilms may be at play and take appropriate measures.

Epidemic Trends and Biofilm Formation Mechanisms of Haemophilus influenzae: Insights into Clinical Implications and Prevention Strategies

Haemophilus influenzae (H. influenzae) is a significant pathogen responsible for causing respiratory tract infections and invasive diseases, leading to a considerable disease burden. The Haemophilus influenzae type b (Hib) conjugate vaccine has notably decreased the incidence of severe infections caused by Hib strains, and other non-typable H. influenzae (NTHi) serotypes have emerged as epidemic strains worldwide. As a result, the global epidemic trends and antibiotic resistance characteristics of H. influenzae have been altered. Researches on the virulence factors of H. influenzae, particularly the mechanisms underlying biofilm formation, and the development of anti-biofilm strategies hold significant clinical value. This article provides a summary of the epidemic trends, typing methods, virulence factors, biofilm formation mechanisms, and prevention strategies of H. influenzae. The increasing prevalence of NTHi strains and antibiotic resistance among H. influenzae, especially the high β-lactamase positivity and the emergence of BLNAR strains have increased clinical difficulties. Understanding its virulence factors, especially the formation mechanism of biofilm, and formulating effective anti-biofilm strategies may help to reduce the clinical impact. Therefore, future research efforts should focus on developing new approaches to prevent and control H. influenzae infections.

Otopathogens in the middle ear and nasopharynx of children with recurrent acute otitis media

OBJECTIVE

This study aimed to describe the microbiology of the middle ear and nasopharynx, determining the prevalence of Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis in a group of children vaccinated with pneumococcal conjugate vaccine (PCV) who underwent ventilation tube insertion for recurrent acute otitis media.

METHODS

We analyzed 278 middle ear effusion and 139 nasopharyngeal samples obtained from 139 children who underwent myringotomy and ventilation tube insertion for recurrent acute otitis media between June 2017 and June 2021. The children's ages ranged from 9 months to 9 years, 10 months, with a median of 21 months. The patients had no signs of acute otitis media or respiratory tract infection and were not on antibiotic therapy at the time of the procedure. The middle ear effusion and nasopharyngeal samples were collected with an Alden-Senturia aspirator and a swab, respectively. Bacteriological studies and multiplex PCR were performed for the detection of the three pathogens. Direct molecular determination of pneumococcal serotypes was performed by real-time PCR. The chi-square test was used to verify associations between categorical variables and measures of strength of association based on prevalence ratios, considering a 95% confidence interval a 5% significance level.

RESULTS

Vaccination coverage was 77.7% with the basic regimen plus booster dose and 22.3% with the basic regimen alone. Middle ear effusion culture identified H. influenzae in 27 children (19.4%), S. pneumoniae in 7 (5.0%), and M. catarrhalis in 7 (5.0%). PCR detected H. influenzae in 95 children (68.3%), S. pneumoniae in 52 (37.4%), and M. catarrhalis in 23 (16.5%), a three-to seven-fold increase compared to culture. In the nasopharynx, culture isolated H. influenzae in 28 children (20.1%), S. pneumoniae in 29 (20.9%), and M. catarrhalis in 12 (8.6%). PCR identified H. influenzae in 84 children (60.4%), S. pneumoniae in 58 (41.7%), and M. catarrhalis in 30 (21.5%), a two-to three-fold increase in detection. The most common pneumococcal serotype was 19A, both in the ears and the nasopharynx. In the ears, of the 52 children who had pneumococcus, 24 (46.2%) had serotype 19A. In the nasopharynx, of the 58 patients who had pneumococcus, 37 (63.8%) had serotype 19A. Of all 139 children, 53 (38.1%) had polymicrobial samples (more than 1 of the 3 otopathogens) in the nasopharynx. Of the 53 children who had polymicrobial samples in the nasopharynx, 47 (88.7%) also had 1 of the 3 otopathogens in the middle ear, mainly H. influenzae (40%-75.5%), especially when it was found in the nasopharynx in conjunction with S. pneumoniae.

CONCLUSION

The prevalence of bacteria in a group of Brazilian children immunized with the PCV who required ventilation tube insertion for recurrent acute otitis media was similar to that reported in other parts of the world after the advent of PCV. H. influenzae was the most frequent bacteria, both in the nasopharynx and the middle ear, while S. pneumoniae serotype 19A was the most common pneumococcus in the nasopharynx and middle ear. Polymicrobial colonization of the nasopharynx was strongly associated with detection of H. influenzae in the middle ear.

Biofilm-Forming Bacteria Implicated in Complex Otitis Media in Children in the Post-Heptavalent Pneumococcal Conjugate Vaccine (PCV7) Era

Background: Chronic media with effusion (COME) and recurrent acute otitis media (RAOM) are closely related clinical entities that affect childhood. The aims of the study were to investigate the microbiological profile of otitis-prone children in the post-PCV7 era and, to examine the biofilm-forming ability in association with clinical history and outcome during a two-year post-operative follow-up. Methods: In this prospective study, pathogens from patients with COME and RAOM were isolated and studied in vitro for their biofilm-forming ability. The minimum inhibitory concentrations (MIC) of both the planktonic and the sessile forms were compared. The outcome of the therapeutic method used in each case and patient history were correlated with the pathogens and their ability to form biofilms. Results: Haemophilus influenzae was the leading pathogen (35% in COME and 40% in RAOM), and Streptococcus pneumoniae ranked second (12% in COME and 24% in RAOM). Polymicrobial infections were identified in 5% of COME and 19% of RAOM cases. Of the isolated otopathogens, 94% were positive for biofilm formation. Conclusions: This is the first Greek research studying biofilm formation in complex otitis media-prone children population in the post-PCV7 era. High rates of polymicrobial infections, along with treatment failure in biofilms, may explain the lack of antimicrobial efficacy in otitis-prone children.

Antibacterial activity of medicinal plants in Indonesia on Streptococcus pneumoniae

Streptococcus pneumoniae is a human pathogenic bacterium able to cause invasive pneumococcal diseases. Some studies have reported medicinal plants having antibacterial activity against pathogenic bacteria. However, antibacterial studies of medicinal plants against S. pneumoniae remains limited. Therefore, this study aims to describe the antibacterial activity of medicinal plants in Indonesia against S. pneumoniae. Medicinal plants were extracted by maceration with n-hexane, ethanol, ethyl acetate and water. Antibacterial activity was defined by inhibition zone and minimum inhibitory concentration (MIC). Bactericidal activity was measured by culture and time-killing measurement. Methods used to describe the mechanism of action of the strongest extract were done by absorbance at 595 nm, broth culture combined with 1% crystal violet, qRT-PCR targeting lytA, peZT and peZA, and transmission electron microscope to measure bacterial lysis, antibiofilm, LytA and peZAT gene expression, and ultrastructure changes respectively. Among 13 medicinal plants, L. inermis Linn. ethyl acetate extract showed the strongest antibacterial activity against S. pneumoniae with an MIC value of 0,16 mg/ml. Bactericidal activity was observed at 0,16 mg/ml for 1 hour incubation. Lawsonia inermis extract showed some mechanism of actions including bacterial lysis, antibiofilm, and ultrastructure changes such as cell wall disruption, decreasing cell membrane integrity and morphological disorder. Increasing of lytA and decreasing of peZA and peZT expression were also observed after incubation with the extract. In addition, liquid chromatography mass spectrophotometer showed phenolic compounds as the commonest compound in L. inermis ethyl acetate extract. This study describes the strong antibacterial activity of L. inermis with various mechanism of action including ultrastructure changes.

Colonization by Streptococcus pneumoniae among children in Porto Velho, Rondônia, Western Brazilian Amazon

Streptococcus pneumoniae is one of the primary pathogens that are associated with acute respiratory infections (ARI) that cause high rates of morbidity and mortality among children under five years of age in developed and developing countries. This study aimed to determine the prevalence of nasopharyngeal colonization, the antimicrobial resistance profile, and the capacity for biofilm formation by S. pneumoniae isolated from children aged 0-6 years with ARI throughout the Porto Velho-RO. A total of 660 swabs were collected from children with ARI. Molecular and biochemical tests were performed to characterize the isolates. The disk-difusion method and the E-test were used for antimicrobial sensitivity testing (TSA). Biofilm formation capacity was assessed using microtiter plate assays, and serotype detection was acheived using polymerase chain reaction (PCR) analyses. The colonization rate for S. pneumoniae was 8.9% (59/660) and exhibited a high prevalence in children under 23 months of age 64.4% (38/59). The observed serotypes were 9V and 19F with frequencies of 1.7% (1/59) and 13.6% (8/59), respectively. The antimicrobial susceptibility test revealed 100% (59/59) sensitivity to vancomycin. In contrast, trimethoprim and oxacillin exhibited high resistance rates of 76.3% (45/59) and 52.5% (31/59), respectively. Of the biofilm-forming isolates, 54.8% (23/42) possessed resistance to some antimicrobials. In this study, S. pneumoniae showed high rates of antimicrobial resistance and the ability to form biofilms, as these are factors that favor bacterial persistence and can cause serious damage to the host.

Targeting bacteria causing otitis media using nanosystems containing nonspherical gold nanoparticles and ceragenins

Aim: To evaluate the antibacterial and antibiofilm activity of ceragenin-conjugated nonspherical gold nanoparticles against the most common agents of otitis media. Methods: Minimal inhibitory and bactericidal concentrations and colony-counting assays, as well as colorimetric and fluorimetric methods, were used to estimate the antibacterial activity of compounds in phosphate-buffered saline and human cerumen. The nanosystems' biocompatibility and ability to decrease IL-8 release was tested using keratinocyte cells. Results: The tested compounds demonstrated strong antimicrobial activity against planktonic and biofilm cultures at nontoxic doses due to the induction of oxidative stress followed by the damage of bacterial membranes. Conclusion: This study indicates that ceragenin-conjugated nonspherical gold nanoparticles have potential as new treatment methods for eradicating biofilm-forming pathogens associated with otitis media.

Nasopharyngeal carriage rates and serotype distribution of Streptococcus pneumoniae among school children with acute otitis media in Central Java, Indonesia

Streptococcus pneumoniae is a common bacterial pathogen that causes acute otitis media (AOM) in children. In this study, we investigated nasopharyngeal carriage rates and serotype distributions of S. pneumoniae among school children with AOM in Banyumas Regency, Central Java, Indonesia, from 2018 to 2019. Nasopharyngeal swab specimens and demographic data were collected from 122 children between the ages of 6 and 12. The specimens were cultured for the identification of S. pneumoniae, and serotyping was performed using a sequential multiplex PCR assay. We found that the S. pneumoniae carriage rate was 73 % (89/122) among children with AOM. Serotypes 23A (11 %) and 6A/6B (10 %) were the most common serotypes among the 91 cultured S. pneumoniae strains, followed by 3 (8 %), 14 (7 %), 6C/6D (7 %), 11A/11D (6 %), 15B/15C (4 %) and 35 B (4 %). Moreover, 41 % of the strains could be covered by the 13-valent pneumococcal conjugate vaccine, PCV13. In conclusion, high nasopharyngeal carriage rates of S. pneumoniae were found in school children with AOM, with almost half of the strains being the vaccine-type. This finding provides a baseline for nasopharyngeal carriage of S. pneumoniae in school children with AOM and supports the implementation of pneumococcal conjugate vaccines in Indonesia.

Role of Surfactant Protein D in Experimental Otitis Media

Surfactant protein D (SP-D) is a C-type collectin and plays an important role in innate immunity and homeostasis in the lung. This study studied SP-D role in the nontypeable Haemophilus influenzae (NTHi)-induced otitis media (OM) mouse model. Wild-type C57BL/6 (WT) and SP-D knockout (KO) mice were used in this study. Mice were injected in the middle ear (ME) with 5 μL of NTHi bacterial solution (3.5 × 105 CFU/ear) or with the same volume of sterile saline (control). Mice were sacrificed at 3 time points, days 1, 3, and 7, after treatment. We found SP-D expression in the Eustachian tube (ET) and ME mucosa of WT mice but not in SP-D KO mice. After infection, SP-D KO mice showed more intense inflammatory changes evidenced by the increased mucosal thickness and inflammatory cell infiltration in the ME and ET compared to WT mice (p < 0.05). Increased bacterial colony-forming units and cytokine (IL-6 and IL-1β) levels in the ear washing fluid of infected SP-D KO mice were compared to infected WT mice. Molecular analysis revealed higher levels of NF-κB and NLRP3 activation in infected SP-D KO compared to WT mice (p < 0.05). In vitro studies demonstrated that SP-D significantly induced NTHi bacterial aggregation and enhanced bacterial phagocytosis by macrophages (p < 0.05). Furthermore, human ME epithelial cells showed a dose-dependent increased expression of NLRP3 and SP-D proteins after LPS treatment. We conclude that SP-D plays a critical role in innate immunity and disease resolution through enhancing host defense and regulating inflammatory NF-κB and NLRP3 activation in experimental OM mice.

Non-typeable Haemophilus influenzae chronic colonization in chronic obstructive pulmonary disease (COPD)

Haemophilus influenzae is the most common cause of bacterial infection in the lungs of chronic obstructive pulmonary disease (COPD) patients and contributes to episodes of acute exacerbation which are associated with increased hospitalization and mortality. Due to the ability of H. influenzae to adhere to host epithelial cells, initial colonization of the lower airways can progress to a persistent infection and biofilm formation. This is characterized by changes in bacterial behaviour such as reduced cellular metabolism and the production of an obstructive extracellular matrix (ECM). Herein we discuss the multiple mechanisms by which H. influenzae contributes to the pathogenesis of COPD. In particular, mechanisms that facilitate bacterial adherence to host airway epithelial cells, biofilm formation, and microbial persistence through immune system evasion and antibiotic tolerance will be discussed.

Pneumococcal susceptibility to antibiotics in carriage: a 17 year time series analysis of the adaptive evolution of non-vaccine emerging serotypes to a new selective pressure environment

BACKGROUND

Pneumococcal conjugate vaccine (PCV) implementations led to major changes in serotype distribution and antibiotic resistance in carriage, accompanied by changes in antibiotic consumption.

OBJECTIVES

To assess the dynamic patterns of antimicrobial non-susceptibility across non-PCV13 serotypes following PCV implementations.

METHODS

We conducted a quasi-experimental interrupted time series analysis based on a 17 year French nationwide prospective cohort. From 2001 to 2018, 121 paediatricians obtained nasopharyngeal swabs from children with acute otitis media who were aged 6 months to 2 years. The main outcome was the rate of penicillin-non-susceptible pneumococci (PNSP), analysed by segmented regression.

RESULTS

We enrolled 10 204 children. After PCV13 implementation, the PNSP rate decreased (-0.5% per month; 95% CI -0.9 to -0.1), then, after 2014, the rate slightly increased (+0.7% per month; 95% CI +0.2 to +1.2). Global antibiotic use within the previous 3 months decreased over the study period (-22.2%; 95% CI -33.0 to -11.3), but aminopenicillin use remained high. Among the main non-PCV13 serotypes, four dynamic patterns of penicillin susceptibility evolution were observed, including unexpected patterns of serotypes emerging while remaining or even becoming penicillin susceptible. In contrast to PNSP strains, for these latter patterns, the rate of co-colonization with Haemophilus influenzae increased concomitant with their emergence.

CONCLUSIONS

In a context of continuing high antibiotic selective pressure, a progressive increase in PNSP rate was observed after 2014. However, we highlighted an unexpected variability in dynamic patterns of penicillin susceptibility among emerging non-PCV13 serotypes. Antibiotic resistance may not be the only adaptive mechanism to antimicrobial selective pressure, and co-colonization with H. influenzae may be involved.

Anatomical site-specific immunomodulation by bacterial biofilms

PURPOSE OF REVIEW

The human body plays host to bacterial biofilms across diverse anatomical sites. The treatment of pathogenic biofilm infection is confounded by their high rate of antibiotic resistance. Therefore, it is critical to understand the interplay between these biofilms and the host immune system to develop new tactics to combat these infections.

RECENT FINDINGS

Bacterial biofilms and the components they produce affect and are affected by the host immune system. Host anatomical sites represent distinct niches in which defined bacterial biofilms are able to form and interact with the host immune system. For persistent colonization to occur, the bacteria must either avoid or suppress the host immune system, or induce an immune response that facilitates their perpetuation.

SUMMARY

Commensal bacterial biofilms form a protective barrier against colonization by pathogens. Using similar mechanisms, bacteria modulate the immune system to orchestrate persistence and sometimes disease. Clinicians must balance the need to avoid disturbing beneficial commensal biofilms with the difficulty in preventing or treating pathogenic bacterial biofilms such as those that develop on medical implants and open wounds.

Asian Sand Dust Particles Increased Pneumococcal Biofilm Formation in vitro and Colonization in Human Middle Ear Epithelial Cells and Rat Middle Ear Mucosa

INTRODUCTION

Air pollutants such as Asian sand dust (ASD) and Streptococcus pneumoniae are risk factors for otitis media (OM). In this study, we evaluate the role of ASD in pneumococcal in vitro biofilm growth and colonization on human middle ear epithelium cells (HMEECs) and rat middle ear using the rat OM model.

METHODS

S. pneumoniae D39 in vitro biofilm growth in the presence of ASD (50-300 μg/ml) was evaluated in metal ion-free BHI medium using CV-microplate assay, colony-forming unit (cfu) counts, resazurin staining, scanning electron microscopy (SEM), and confocal microscopy (CF). Biofilm gene expression analysis was performed using real-time RT-PCR. The effects of ASD or S. pneumoniae individually or on co-treatment on HMEECs were evaluated by detecting HMEEC viability, apoptosis, and reactive oxygen species (ROS) production. In vivo colonization of S. pneumoniae in the presence of ASD was evaluated using the rat OM model, and RNA-Seq was used to evaluate the alterations in gene expression in rat middle ear mucosa.

RESULTS

S. pneumoniae biofilm growth was significantly (P < 0.05) elevated in the presence of ASD. SEM and CF analysis revealed thick and organized pneumococcal biofilms in the presence of ASD (300 μg/ml). However, in the absence of ASD, bacteria were unable to form organized biofilms, the cell size was smaller than normal, and long chain-like structures were formed. Biofilms grown in the presence of ASD showed elevated expression levels of genes involved in biofilm formation (luxS), competence (comA, comB, ciaR), and toxin production (lytA and ply). Prior exposure of HMEECs to ASD, followed by treatment for pneumococci, significantly (P < 0.05) decreased cell viability and increased apoptosis, and ROS production. In vivo experiment results showed significantly (P < 0.05) more than 65% increased bacteria colonization in rat middle ear mucosa in the presence of ASD. The apoptosis, cell death, DNA repair, inflammation and immune response were differentially regulated in three treatments; however, number of genes expressed in co-treatments was higher than single treatment. In co-treatment, antimicrobial protein/peptide-related genes (S100A family, Np4, DEFB family, and RATNP-3B) and OM-related genes (CYLD, SMAD, FBXO11, and CD14) were down regulated, and inflammatory cytokines and interleukins, such as IL1β, and TNF-related gene expression were elevated.

CONCLUSION

ASD presence increased the generation of pneumococcal biofilms and colonization.

Bacterial biofilm in adenoids of children with chronic otitis media. Part II: a case-control study of nasopharyngeal microbiota, virulence, and resistance of biofilms in adenoids

Background: We previously described that adenoid tissue in children with chronic otitis media (COM) contained more mucosal biofilms than adenoid tissue removed for hypertrophy.Aims/objectives: The aim of the second part was to characterize nasopharyngeal microbiota and explore virulence of the most common middle ear pathogens.Material and methods: Bacteriological analysis was performed following a culture-based approach on the samples recovered from 30 patients of COM group (15 biofilm-positive and 15 biofilm-negative) and from 30 patients of a control group (15 biofilm-positive and 15 biofilm-negative). Virulence factors of Streptococcus pneumoniae, Streptococcus pyogenes, and Haemophilus influenzae were investigated.Results: The most frequent species were Firmicutes followed by Proteobacteria and Actinobacteria. The presence of biofilm was statistically associated with an increase of the number of bacterial species and Firmicutes phylum regardless of the condition (case/control). No virulence factors associated with invasive isolates were found for the most common middle ear pathogens.Conclusions and significance: This case-control study demonstrated that the presence of COM plus biofilm was associated with a given microbiota which contained more Firmicutes. Our study allows a better understanding of physiopathological mechanisms involved in chronic otitis media and paves the way for further investigations.

Photoinactivation of Moraxella catarrhalis Using 405-nm Blue Light: Implications for the Treatment of Otitis Media

Moraxella catarrhalis is one of the major otopathogens of otitis media (OM) in childhood. M. catarrhalis tends to form biofilm, which contributes to the chronicity and recurrence of infections, as well as resistance to antibiotic treatment. In this study, we aimed to investigate the effectiveness of antimicrobial blue light (aBL; 405 nm), an innovative nonpharmacological approach, for the inactivation of M. catarrhalis OM. M. catarrhalis either in planktonic suspensions or 24-h old biofilms were exposed to aBL at the irradiance of 60 mW cm^-2 . Under an aBL exposure of 216 J cm^-2 , a >4-log₁₀ colony-forming units (CFU) reduction in planktonic suspensions and a >3-log₁₀ CFU reduction in biofilms were observed. Both transmission electron microscopy and scanning electron microscopy revealed aBL-induced morphological damage in M. catarrhalis. Ultraperformance liquid chromatography results indicated that protoporphyrin IX and coproporphyrin were the two most abundant species of endogenous photosensitizing porphyrins. No statistically significant reduction in the viability of HaCaT cells was observed after an aBL exposure of up to 216 J cm^-2 . Collectively, our results suggest that aBL is potentially an effective and safe alternative therapy for OM caused by M. catarrhalis. Further in vivo studies are warranted before this optical approach can be moved to the clinics.

A Cross-Reactive Protein Vaccine Combined with PCV-13 Prevents Streptococcus pneumoniae- and Haemophilus influenzae-Mediated Acute Otitis Media

Acute otitis media is one of the most common childhood infections worldwide. Currently licensed vaccines against the common otopathogen Streptococcus pneumoniae target the bacterial capsular polysaccharide and confer no protection against nonencapsulated strains or capsular types outside vaccine coverage. Mucosal infections such as acute otitis media remain prevalent, even those caused by vaccine-covered serotypes. Here, we report that a protein-based vaccine, a fusion construct of epitopes of CbpA to pneumolysin toxoid, confers effective protection against pneumococcal acute otitis media for non-PCV-13 serotypes and enhances protection for PCV-13 serotypes when coadministered with PCV-13. Having cross-reactive epitopes, the fusion protein also induces potent antibody responses against nontypeable Haemophilus influenzae and S. pneumoniae, engendering protection against acute otitis media caused by emerging unencapsulated otopathogens. These data suggest that augmenting capsule-based vaccination with conserved, cross-reactive protein-based vaccines broadens and enhances protection against acute otitis media.

A systematic review and meta-analysis of antimicrobial resistance in paediatric acute otitis media

OBJECTIVE OF REVIEW

Acute otitis media (AOM) is the largest cause of antimicrobial prescriptions amongst children in developed countries. Excessive and inappropriate prescribing is known to drive antimicrobial resistance, but less is known of antimicrobial resistance in AOM-associated bacteria.

TYPE OF REVIEW & SEARCH STRATEGY

We conducted a systematic review and meta-analysis of bacterial prevalence and antimicrobial resistance in studies of paediatric AOM identified from Ovid Medline, Embase and the Cochrane library.

RESULTS

From 48 unique studies, 15,871 samples were included. Only 0.67 (CI 0.63-0.71) of all ear samples grew a bacterial pathogen. The most common bacterial causes of AOM in children were Streptococcus pneumoniae 0.30 (CI 0.27-0.32), Haemophilus influenza 0.23 (CI 0.20-0.26), and Moraxella catarrhalis 0.05 (CI 0.04-0.06). Resistance patterns varied amongst organisms and antimicrobial agents. The pooled proportion of bacterial culture-positive episodes of AOM that could be effectively treated with amoxicillin was 0.85 (CI 0.76-0.94), erythromycin was 0.64 (0.48-0.78) and amoxicillin-clavulanate was 0.95 (CI 0.85-0.98).

CONCLUSION

We have demonstrated the bacteriology and antimicrobial resistance patterns of AOM. Of samples which grew bacteria, on average approximately 15% of isolates demonstrated resistance to amoxicillin; a typical first-line agent. Greater understanding of local bacteriology and resistance patterns is needed to enable improved antimicrobial stewardship.

Diagnosis and treatment of biofilm infections in children

PURPOSE OF REVIEW

Biofilm-associated infections cause difficulties in the management of childhood chronic infections and other diseases, due to the invasive nature of interventions which are often necessary for definitive management. Despite their importance, there are challenges in diagnosing biofilm infections and gaps in clinicians' understanding regarding the significance of biofilms.

RECENT FINDINGS

Many chronic infections associated with biofilms remain difficult or impossible to eradicate with conventional therapy. Surgical intervention, implant removal or long-term intermittent or suppressive antimicrobial therapy may be required. There are still significant challenges in detecting biofilms which presents a barrier in clinical practice and research. Novel therapies to disrupt biofilms are currently under investigation, which may help reduce the impact of antimicrobial resistance.

SUMMARY

Biofilm-associated infection should be considered wherever there is clinical concern for an infection affecting prosthetic material, where there is a predisposing condition such as suppurative lung disease; or in the setting of chronic or relapsing infections which may be culture negative. New diagnostic methods for detecting biofilms are a research priority for both clinical diagnosis and the ability to conduct high quality clinical trials of novel antibiofilm interventions.

Determination of Biofilm-Forming Capacity of Otopathogens Isolated from Discharging Ears in Children with Chronic Otitis Media

Chronic otitis media is a common disease of the developing world with persistent ear discharge, leading to major complications. This study describes the microorganisms isolated from the middle ear and nasopharynx of children with chronically discharging ears. Middle ear and nasopharyngeal swabs from 89 children were studied, and the microorganisms isolated were assessed for biofilm-forming ability. Methicillin-susceptible Staphylococcus aureus was common in the nasopharynx, while the middle ear showed predominantly pseudomonas and Methicillin-resistant S. aureus. Pseudomonas aeruginosa showed strong biofilm formation, whereas Escherichia coli, Proteus sp. and Providentia sp. were weak biofilm producers. S. aureus isolates were negative for biofilm formation.