Epidemiologic study of conjunctivitis-otitis syndrome

Ceftriaxone use for acute otitis media: Associated factors in a large U.S. primary care population

BACKGROUND

Clinicians in the authors' primary care academic practice have anecdotally perceived an increased use of intramuscular (IM) ceftriaxone, particularly for otitis-conjunctivitis in recent years (pre-pandemic). Increasing rates of ceftriaxone administration for acute otitis media (AOM) may be an important marker of antimicrobial resistance.

OBJECTIVE

We aimed to characterize the population of patients who received ceftriaxone for treatment of AOM, testing our hypothesis that patients with concomitant conjunctivitis would have increased rates of ceftriaxone receipt.

DESIGN/METHODS

We reviewed cases of AOM at a large U.S. primary care practice from August 2017 to July 2019. We determined the association between each of the following variables and ceftriaxone injection using multivariate analysis: age at AOM diagnosis, provider type, insurance (public vs private), season of year, and presence of conjunctivitis.

RESULTS

There were 6028 AOM episodes in 5195 patients resulting in a total of 7688 patient encounters. Of these episodes, 642 (10.7%) had a concurrent diagnosis of conjunctivitis; 362 (6.0%) ultimately received ceftriaxone. Conjunctivitis was the strongest predictor of treatment with ceftriaxone. The proportion of episodes with conjunctivitis treated with ceftriaxone was 14.5% (93/642) versus 5.0% (269/5386) without conjunctivitis (p < 0.0001). Patients who received ceftriaxone were younger; mean age (SD) for patients receiving ceftriaxone was 14.0 (8.8) months versus 25.0 (23.4) months (p < 0.0001).

CONCLUSION(S)

There is a strong correlation between the presence of conjunctivitis and receipt of IM ceftriaxone in this large U.S. academic primary care clinic. Younger age was also associated with ceftriaxone treatment. Further study on emerging resistance patterns and implications for management of AOM in young children is warranted.

New Approach to the Surveillance of Pediatric Infectious Diseases From Ambulatory Pediatricians in the Digital Era

BACKGROUND

Many ambulatory networks in several countries have established syndromic surveillance systems to detect outbreaks of different illnesses. Here, we describe a new Pediatric and Ambulatory Research in Infectious diseases network that combined automated data extraction from the computers of primary care pediatricians.

METHODS

Pediatricians who used the same software, AxiSanté 5-Infansoft for electronic medical records were specially trained in infectious diseases, encouraged to comply with French treatments' recommendations, use of point-of-care tests and vaccination guidelines. Infectious disease diagnoses in children <16 years old in the records triggered automatic data extraction of complete records. A quality control process and external validation were developed.

RESULTS

From September 2017 to February 2020, 107 pediatricians enrolled 57,806 children (mean age 2.9 ± 2.6 years at diagnosis) with at least one infectious disease diagnosis among those followed by the network. Among the 118,193 diagnoses, the most frequent were acute otitis media (n = 44,924, 38.0%), tonsillopharyngitis (n = 13,334, 11.3%), gastroenteritis (n = 12,367, 10.5%), influenza (n = 11,062, 9.4%), bronchiolitis (n = 10,531, 8.9%), enteroviral infections (n = 8474, 7.2%) and chickenpox (n = 6857, 5.8%). A rapid diagnostic test was performed in 84.7% of cases of tonsillopharyngitis and was positive in 44%. The antibiotic recommendations from French guidelines were strictly followed: amoxicillin was the most prescribed antibiotic and less than 10% of presumed viral infections were treated.

CONCLUSIONS

This "tailor-made" network set up with quality controls and external validation represents a new approach to the surveillance of pediatric infectious diseases in the digital era and could highly optimize pediatric practices.

Prevalence of Streptococcus pneumoniae in conjunctival flora and association with nasopharyngeal carriage among children in a Vietnamese community

Conjunctival pneumococcal serotypes among members of a community have not been investigated well. We determined the prevalence and association of Streptococcus pneumoniae in the nasopharynx and conjunctiva among children in a community before pneumococcal conjugate vaccine introduction. In October 2016, conjunctival and nasopharyngeal swabs were collected from children (< 24 months old) and nasopharyngeal swabs from mothers in Nha Trang, Vietnam. Quantitative lytA PCR and DNA microarray were performed to detect and serotype S. pneumoniae. The association between S. pneumoniae in the nasopharynx and conjunctiva was evaluated using multivariable logistic regression model. Among 698 children, 62 (8.9%, 95% CI 6.9-11.2%) were positive for S. pneumoniae in the conjunctiva. Non-encapsulated S. pneumoniae were most commonly identified, followed by serotypes 6A, 6B, and 14. Nasopharyngeal and conjunctival detection were positively associated (aOR 47.30, 95% CI 24.07-92.97). Low birth-weight, day-care attendance, and recent eye symptoms were independently associated with S. pneumoniae detection in the conjunctiva (aOR 11.14, 95% CI 3.76-32.98, aOR 2.19, 95% CI 1.45-3.31, and aOR 3.59, 95% CI 2.21-5.84, respectively). Serotypes and genotypes in the conjunctiva and nasopharynx matched in 87% of the children. Three mothers' nasopharyngeal pneumococcal samples had matched serotype and genotype with their child's in the conjunctiva and nasopharynx. S. pneumoniae presence in nasopharynx and conjunctiva were strongly associated. The high concordance of serotypes suggests nasopharyngeal carriage may be a source of transmission to the conjunctiva.

Predominant role of Haemophilus influenzae in the association of conjunctivitis, acute otitis media and acute bacterial paranasal sinusitis in children

Haemophilus influenzae is a predominant pathogen for conjunctivitis, acute otitis media and acute bacterial paranasal sinusitis in children. We undertook this study to investigate the possible association among these diseases. Children younger than 18-year-old with a diagnosis of bacterial conjunctivitis plus acute otitis media and/or acute bacterial paranasal sinusitis during 2009-2018 were included. Sampling for bacterial cultures was obtained from the lower palpebral conjunctiva and/or ear discharge with cotton-tipped swabs. A total of 67 children were recruited and the age was 29.5 (± 22.4) months in average. Fifty-seven children had conjunctivitis-otitis media syndrome and eight of them had a concurrent diagnosis of acute paranasal sinusitis. Ten children had conjunctivitis and acute paranasal sinusitis simultaneously. Clusters in household were observed in 50.7% children. Most common isolates were Haemophilus influenzae (70%), Moraxella catarrhalis (18%), and Staphylococcus aureus (8%). Antibiotic resistance rate of H. influenzae was 80% for ampicillin, 18% for amoxicillin-clavulanate, and 11% for the second or third-generation cephalosporins. Apart from well-known conjunctivitis-otitis media syndrome, acute paranasal sinusitis may also be linked to conjunctivitis with a similar pathogenic process. Simultaneous presence of these infections may guide the choice of empiric antibiotics toward H. influenzae.

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

Background

Biofilm production by Haemophilus influenzae and Streptococcus pneumoniae has been implicated in the pathogenesis of otitis media, mainly in chronic and recurrent cases. We studied the “in vitro” biofilm production by these 2 species isolated alone or together from the nasopharynx of children with acute otitis media.

Methods

The studied strains were from 3 pneumococcal conjugate vaccine (PCV) periods: pre-PCV7, post-PCV7/pre-PCV13 and post-PCV13. A modified microtiter plate assay with crystal violet stain was used to study the biofilm production of 182 H. influenzae and 191 S. pneumoniae strains.

Results

Overall, 117/181 (64.6%) H. influenzae and 128/191 (66.8%) S. pneumoniae strains produced biofilm. The proportion of biofilm-producing H. influenzae strains was greater with than without the isolation of S. pneumoniae in the same sample (75.5% vs 52.3%, p = 0.001). Conversely, the proportion of biofilm-producing S. pneumoniae strains was not affected by the presence or not of H. influenzae (66.3% vs 67.4%). S. pneumoniae serotypes 6B, 15B/C, 19A, 35F and 35B were the better biofilm producers (80%). Serotypes 11A, 14, 15A, 19F and 19A were more associated with H. influenzae biofilm-producing strains. Overall, 89/94 (94.6%) of cases with combined isolation showed biofilm production by S. pneumoniae or H. influenzae.

Conclusion

This study emphasizes the high proportion of biofilm production by H. influenzae and S. pneumoniae strains isolated from the nasopharynx of children with acute otitis media, which reinforces the results of studies suggesting the importance of biofilm in the pathogenesis of acute otitis media.

Electronic supplementary material

The online version of this article (10.1186/s12879-018-3657-9) contains supplementary material, which is available to authorized users.

Infantile Acute Conjunctivitis Induced by β-Lactamase-Positive Amoxicillin-Clavulanate-Resistant Strain of Haemophilus influenzae: A Report of Three Cases

This study is a retrospectively recruited case series. We report three infants with acute conjunctivitis induced by β-lactamase–positive, ampicillin/clavulanic acid-resistant strains of Haemophilus influenzae (BLPACR). Patients with BLPACR-positive cultures were recruited from among 5,107 patients with inflammatory diseases of the ocular surface who underwent examinations, including bacterial culturing of conjunctival sac or corneal scrapings, between 2000 and 2015. Three BLPACR-positive patients were recruited, including a 10-month-old boy, a 4-month-old girl, and a 7-month-old girl. All three demonstrated BLPACR conjunctivitis. The clinical findings in these patients included fever, mucopurulent discharge, lid swelling, and conjunctival hyperemia. Samples of conjunctival swabs were obtained from all three infants, and BLPACR was isolated from all these conjunctival swabs. Antimicrobial susceptibility testing showed sensitivity to levofloxacin and resistance to ampicillin, cefaclor, and clarithromycin. We conclude that in infantile BLPACR conjunctivitis, simultaneous investigation for the determination of causative organism and antibiotic susceptibility testing are crucial aspects of the medical treatment.

Prevention of early episodes of otitis media by pneumococcal vaccines might reduce progression to complex disease

Otitis media is a common childhood infection of the middle ear and a major cause of morbidity. This multifactorial disease manifests as a spectrum of clinical syndromes from uncomplicated acute otitis media to more complex recurrent and chronic cases (frequently polymicrobial), with the major pathogens involved being Streptococcus pneumoniae and non-typeable Haemophilus influenzae. Pneumococcal conjugate vaccines (PCVs) target only a few serotypes that cause otitis media; however, results from studies suggest that existing PCVs can prevent early episodes of disease associated with vaccine serotypes, resulting in a reduction of subsequent complex cases caused by non-vaccine serotypes and other otopathogens, which contribute considerably to the disease burden. In this Review, we discuss the role of pneumococcus in the disease continuum and assess clinical evidence showing the effect of prevention of early episodes on the complex interplay between bacterial species implicated in otitis media.

Non typable-Haemophilus influenzae biofilm formation and acute otitis media

BACKGROUND

Non-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.

METHODS

We 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).

RESULTS

At 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).

CONCLUSION

We 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.

Non-typeable Haemophilus influenzae, an under-recognised pathogen

Non-typeable Haemophilus influenzae (NTHi) is a major cause of mucosal infections such as otitis media, sinusitis, conjunctivitis, and exacerbations of chronic obstructive pulmonary disease. In some regions, a strong causal relation links this pathogen with infections of the lower respiratory tract. In the past 20 years, a steady but constant increase has occurred in invasive NTHi worldwide, with perinatal infants, young children, and elderly people most at risk. Individuals with underlying comorbidities are most susceptible and infection is associated with high mortality. β-lactamase production is the predominant mechanism of resistance. However, the emergence and spread of β-lactamase-negative ampicillin-resistant strains in many regions of the world is of substantial concern, potentially necessitating changes to antibiotic treatment guidelines for community-acquired infections of the upper and lower respiratory tract and potentially increasing morbidity associated with invasive NTHi infections. Standardised surveillance protocols and typing methodologies to monitor this emerging pathogen should be implemented. International scientific organisations need to raise the profile of NTHi and to document the pathobiology of this microbe.

Genetic characteristics of Haemophilus influenzae and Streptococcus pneumoniae isolated from children with conjunctivitis-otitis media syndrome

Acute conjunctivitis is the most common ocular disorders among children and frequently concomitant with acute otitis media (AOM) as conjunctivitis-otitis syndrome. In this study, we evaluated prevalence of causative pathogens and PCR-based genotypes of Haemophilus influenzae and Streptococcus pneumoniae among children with conjunctivitis-otitis media syndrome. Nontypeable H. influenzae (NTHi) is identified most often at 61.8% in conjunctiva exudates followed by S. pneumoniae at 28.2% and Moraxella catarrhalis at 19.1%. Genetic β-lactamase nonproducing ampicillin resistant (gBLNAR) strains of NTHi and genetic penicillin resistant S. pneumoniae (gPRSP) were identified at 72.1% and at 74.2% among conjunctiva isolates by polymerase chain reaction (PCR), respectively. Pneumococcal strains having either ermB or mefE genes were identified at 93.5% among conjunctiva isolates. The restriction fragment of patterns of 89.7% pairs of H. influenzae isolates and 100% pairs of pneumococcal isolates from conjunctiva exudates, middle ear fluids (MEFs) and nasopharyngeal swabs were identical. In contrast to the previous reports, most prevalent strains from conjunctivitis-otitis media syndrome was BLNAR H. influenzae in this study. The causative pathogen responsible for acute conjunctivitis will be originated from the nasopharynx. In the absence of MEFs one can possibly rely on the nasopharyngeal culture to guide an appropriate treatment.

Efficacy and safety of azithromycin 1.5% eye drops in paediatric population with purulent bacterial conjunctivitis

Objective

To determine the efficacy and safety of azithromycin 1.5% eye drops in a paediatric population with purulent bacterial conjunctivitis.

Patients and methods

This was a multicentre, international, randomised, investigator-masked study in 286 children with purulent discharge and bulbar conjunctival injection. Patients received either azithromycin 1.5% eye drops (twice daily for 3 days) or tobramycin 0.3% eye drops (every 2 h for 2 days, then four times daily for 5 days). Clinical signs were evaluated on day (D) 0, 3 and 7, and cultures on D0 and D7. The primary variable was the clinical cure (absence of bulbar conjunctival injection and discharge) on D3 in the worse eye for patients with positive cultures on D0.

Results

286 patients (mean age 3.2 years; range 1 day–17 years) were included; 203 had positive cultures on D0. Azithromycin was superior to tobramycin in clinical cure rate on D3 (47.1% vs 28.7%, p=0.013) and was non-inferior to tobramycin on D7 (89.2% vs 78.2%, respectively). Azithromycin treatment eradicated causative pathogens, including resistant species, with a similar resolution rate to tobramycin (89.8% vs 87.2%, respectively). These results were confirmed in a subgroup of patients younger than 24 months old.

Conclusions

Azithromycin 1.5% eye drops provided a more rapid clinical cure than tobramycin 0.3% eye drops in the treatment of purulent bacterial conjunctivitis in children, with a more convenient twice-a-day dosing regimen.

Use of the Chinchilla model to evaluate the vaccinogenic potential of the Moraxella catarrhalis filamentous hemagglutinin-like proteins MhaB1 and MhaB2

Moraxella catarrhalis causes significant health problems, including 15–20% of otitis media cases in children and ∼10% of respiratory infections in adults with chronic obstructive pulmonary disease. The lack of an efficacious vaccine, the rapid emergence of antibiotic resistance in clinical isolates, and high carriage rates reported in children are cause for concern. In addition, the effectiveness of conjugate vaccines at reducing the incidence of otitis media caused by Streptococcus pneumoniae and nontypeable Haemophilus influenzae suggest that M. catarrhalis infections may become even more prevalent. Hence, M. catarrhalis is an important and emerging cause of infectious disease for which the development of a vaccine is highly desirable. Studying the pathogenesis of M. catarrhalis and the testing of vaccine candidates have both been hindered by the lack of an animal model that mimics human colonization and infection. To address this, we intranasally infected chinchilla with M. catarrhalis to investigate colonization and examine the efficacy of a protein-based vaccine. The data reveal that infected chinchillas produce antibodies against antigens known to be major targets of the immune response in humans, thus establishing immune parallels between chinchillas and humans during M. catarrhalis infection. Our data also demonstrate that a mutant lacking expression of the adherence proteins MhaB1 and MhaB2 is impaired in its ability to colonize the chinchilla nasopharynx, and that immunization with a polypeptide shared by MhaB1 and MhaB2 elicits antibodies interfering with colonization. These findings underscore the importance of adherence proteins in colonization and emphasize the relevance of the chinchilla model to study M. catarrhalis–host interactions.

Earache

Earache, a common emergency department presentation, may be caused by a variety of conditions, some distant from the ear. This article discusses the diagnosis and treatment of acute otitis media, otitis media with effusion, otitis externa, otitis media with ruptured tympanic membrane or tympanostomy tubes, malignant otitis externa, mastoiditis and petrositis, traumatic ruptured tympanic membrane, cerumen impactions, and foreign bodies in the ears.

The diagnosis and management of acute otitis media

This evidence-based clinical practice guideline is a revision of the 2004 acute otitis media (AOM) guideline from the American Academy of Pediatrics (AAP) and American Academy of Family Physicians. It provides recommendations to primary care clinicians for the management of children from 6 months through 12 years of age with uncomplicated AOM. In 2009, the AAP convened a committee composed of primary care physicians and experts in the fields of pediatrics, family practice, otolaryngology, epidemiology, infectious disease, emergency medicine, and guideline methodology. The subcommittee partnered with the Agency for Healthcare Research and Quality and the Southern California Evidence-Based Practice Center to develop a comprehensive review of the new literature related to AOM since the initial evidence report of 2000. The resulting evidence report and other sources of data were used to formulate the practice guideline recommendations. The focus of this practice guideline is the appropriate diagnosis and initial treatment of a child presenting with AOM. The guideline provides a specific, stringent definition of AOM. It addresses pain management, initial observation versus antibiotic treatment, appropriate choices of antibiotic agents, and preventive measures. It also addresses recurrent AOM, which was not included in the 2004 guideline. Decisions were made on the basis of a systematic grading of the quality of evidence and benefit-harm relationships. The practice guideline underwent comprehensive peer review before formal approval by the AAP. This clinical practice guideline is not intended as a sole source of guidance in the management of children with AOM. Rather, it is intended to assist primary care clinicians by providing a framework for clinical decision-making. It is not intended to replace clinical judgment or establish a protocol for all children with this condition. These recommendations may not provide the only appropriate approach to the management of this problem.

Pathogens implicated in acute otitis media failures after 7-valent pneumococcal conjugate vaccine implementation in France: distribution, serotypes, and resistance levels

BACKGROUND

Before 7-valent pneumococcal conjugate vaccine (PCV7) implementation in France, several studies had described the microbiology of acute otitis media (AOM) treatment failures. The causative pathogens were Streptococcus pneumoniae (Sp) followed by nontypable Haemophilus influenzae (NTHi). The aim of this study was to describe the epidemiology of pathogens involved in AOM treatment failures or recurrences.

METHODS

This French multicentric prospective study enrolled 143 children with AOM treatment failure between 2007 and 2009 observed by 8 ear, nose, and throat specialists. Failure was defined as the persistence of AOM symptoms after at least 48 hours of antibiotic therapy or their recurrence within 4 days after the end of treatment. Standardized history and physical examination findings were recorded, and culture of middle ear fluid (MEF) was obtained.

RESULTS

Mean age was 16.9 ± 9.9 months (median, 13.7). Eighty-eight percent of children had received more than 1 dose of PCV7, and 70.6% attended day care. The most common antibiotic used at the time of treatment failure or recurrence was a combination of amoxicillin and clavulanate (51.1%). Bacteriologic sampling demonstrated that in 35% of cases (n=50), no otopathogen was cultured at the time of treatment failure or recurrence. Similar proportions of Sp and NTHi were observed in the 86 patients (60.1%) from whom only a single species was recovered from MEF (46.5% for Sp, n=40 and 45.3% for NTHi, n=39). Among Sp strains, 4.4% were penicillin susceptible, 77.8% were penicillin intermediate, and 17.8% were fully penicillin resistant, and serotype 19A represented 84.5% of all serotypes detected. Among NTHi isolates, 15.5% (n=7) were β-lactamase-producing strains (including 2 strains with only this mechanism of resistance), and strains with reduced susceptibility by changes in protein binding to penicillin (β-lactamase-negative ampicillin resistant strains) represented 35.5% of cases. Among the 50 sterile MEF samples, polymerase chain reaction was performed in 32, of which 4 were positive for HI, 3 for Sp, and 3 for both.

CONCLUSIONS

Among children with AOM treatment failures in France, Sp and NTHi were equally distributed; 19A was the main Sp serotype, and the main resistance mechanism for NTHi was β-lactamase-negative ampicillin resistance.

Use of the chinchilla model for nasopharyngeal colonization to study gene expression by Moraxella catarrhalis

Young adult chinchillas were atraumatically inoculated with Moraxella catarrhalis via the nasal route. Detailed histopathologic examination of nasopharyngeal tissues isolated from these M. catarrhalis-infected animals revealed the presence of significant inflammation within the epithelium. Absence of similar histopathologic findings in sham-inoculated animals confirmed that M. catarrhalis was exposed to significant host-derived factors in this environment. Twenty-four hours after inoculation, viable M. catarrhalis organisms were recovered from the nasal cavity and nasopharynx of the animals in numbers sufficient for DNA microarray analysis. More than 100 M. catarrhalis genes were upregulated in vivo, including open reading frames (ORFs) encoding proteins that are involved in a truncated denitrification pathway or in the oxidative stress response, as well as several putative transcriptional regulators. Additionally, 200 M. catarrhalis genes were found to be downregulated when this bacterium was introduced into the nasopharynx. These downregulated genes included ORFs encoding several well-characterized M. catarrhalis surface proteins including Hag, McaP, and MchA1. Real-time reverse transcriptase PCR (RT-PCR) was utilized as a stringent control to validate the results of in vivo gene expression patterns as measured by DNA microarray analysis. Inactivation of one of the genes (MC ORF 1550) that was upregulated in vivo resulted in a decrease in the ability of M. catarrhalis to survive in the chinchilla nasopharynx over a 3-day period. This is the first evaluation of global transcriptome expression by M. catarrhalis cells in vivo.

Hag mediates adherence of Moraxella catarrhalis to ciliated human airway cells

Moraxella catarrhalis is a human pathogen causing otitis media in infants and respiratory infections in adults, particularly patients with chronic obstructive pulmonary disease. The surface protein Hag (also designated MID) has previously been shown to be a key adherence factor for several epithelial cell lines relevant to pathogenesis by M. catarrhalis, including NCIH292 lung cells, middle ear cells, and A549 type II pneumocytes. In this study, we demonstrate that Hag mediates adherence to air-liquid interface cultures of normal human bronchial epithelium (NHBE) exhibiting mucociliary activity. Immunofluorescent staining and laser scanning confocal microscopy experiments demonstrated that the M. catarrhalis wild-type isolates O35E, O12E, TTA37, V1171, and McGHS1 bind principally to ciliated NHBE cells and that their corresponding hag mutant strains no longer associate with cilia. The hag gene product of M. catarrhalis isolate O35E was expressed in the heterologous genetic background of a nonadherent Haemophilus influenzae strain, and quantitative assays revealed that the adherence of these recombinant bacteria to NHBE cultures was increased 27-fold. These experiments conclusively demonstrate that the hag gene product is responsible for the previously unidentified tropism of M. catarrhalis for ciliated NHBE cells.

Periorbital and orbital infections

Practitioners frequently have the opportunity to manage the child for whom the chief complaint is a swollen eye. Some children have trivial or self-limited disorders, but others can have sight- or life-threatening problems. Noninfectious causes of the swollen eye include blunt trauma, tumor, local edema, and allergy. Infectious causes can be preseptal or orbital in origin. The differential diagnosis and management of these conditions are considered in this article.

Regions important for the adhesin activity of Moraxella catarrhalis Hag

BACKGROUND

The Moraxella catarrhalis Hag protein, an Oca autotransporter adhesin, has previously been shown to be important for adherence of this respiratory tract pathogen to human middle ear and A549 lung cells.

RESULTS

The present study demonstrates that adherence of M. catarrhalis isogenic hag mutant strains to the human epithelial cell lines Chang (conjunctival) and NCIH292 (lung) is reduced by 50-93%. Furthermore, expressing Hag in a heterologous Escherichia coli background substantially increased the adherence of recombinant bacteria to NCIH292 cells and murine type IV collagen. Hag did not, however, increase the attachment of E. coli to Chang cells. These results indicate that Hag directly mediates adherence to NCIH292 lung cells and collagen, but is not sufficient to confer binding to conjunctival monolayers. Several in-frame deletions were engineered within the hag gene of M. catarrhalis strain O35E and the resulting proteins were tested for their ability to mediate binding to NCIH292 monolayers, middle ear cells, and type IV collagen. These experiments revealed that epithelial cell and collagen binding properties are separable, and that residues 385-705 of this ~2,000 amino acid protein are important for adherence to middle ear and NCIH292 cells. The region of O35E-Hag encompassing aa 706 to 1194 was also found to be required for adherence to collagen. In contrast, beta-roll repeats present in Hag, which are structural features conserved in several Oca adhesins and responsible for the adhesive properties of Yersinia enterocolitica YadA, are not important for Hag-mediated adherence.

CONCLUSION

Hag is a major adherence factor for human cells derived from various anatomical sites relevant to pathogenesis by M. catarrhalis and its structure-function relationships differ from those of other, closely-related autotransporter proteins.

Identification of aMoraxella catarrhalisgene that confers adherence to various human epithelial cell linesin vitro

Moraxella catarrhalis is a pathogen of the human airways. We found that expression of the M. catarrhalis gene mcmA by Escherichia coli increases adherence to epithelial cells 100-fold. Furthermore, we discovered that disrupting mcmA decreases M. catarrhalis adherence to laryngeal and lung cells, which are relevant to pathogenesis by the bacterium.

What is new in otitis media?

The "wait and see" approach in acute otitis media (AOM), consisting of postponing the antibiotic administration for a few days, has been advocated mainly to counteract the increased bacterial resistance in respiratory infections. This approach is not justified in children less than 2 years of age and this for several reasons. First, AOM is an acute inflammation of the middle ear caused in about 70% of cases by bacteria. Redness and bulging of the tympanic membrane are characteristic findings in bacterial AOM. Second, AOM is associated with long-term dysfunction of the inflamed eustachian tube (ET), particularly in children less than 2 years of age. In this age group, the small calibre of the ET together with its horizontal direction result in impaired clearance, ventilation and protection of the middle ear. Third, recent prospective studies have shown poor long-term prognosis of AOM in children below 2 years with at least 50% of recurrences and persisting otitis media with effusion (OME) in about 35% 6 months after AOM. Viruses elicit AOM in about 30% of children. A prolonged course of AOM has been observed when bacterial and viral infections are combined because viral infection is also associated with ET dysfunction in young children. Bacterial and viral testing of the nasopharyngeal aspirate is an excellent tool both for initial treatment and recurrence of AOM. Antibiotic treatment of AOM is mandatory in children less than 2 years of age to decrease inflammation in the middle ear but also of the ET particularly during the first episode. The best choice is amoxicillin because of its superior penetration in the middle ear. Streptococci pneumoniae with intermediary bacterial resistance to penicillin are particularly associated with recurrent AOM. Therefore the dosage of amoxicillin should be 90 mg/kg per day in three doses. In recurrent AOM with beta-lactamase-producing bacilli, amoxicillin should be associated with clavulanic acid at a dose of 6.4 mg/kg per day. The duration of the treatment is not established yet but 10 days is reasonable for a first episode of AOM. OME may be a precursor initiating AOM but also a complication thereof. OME needs a watchful waiting approach. When associated with deafness for 2-3 months in children over 2 years of age, an antibiotic should be given according to the results of the bacterial resistance in the nasopharyngeal aspirate. The high rate of complications of tympanostomy tube insertion outweighs the beneficial effect on hearing loss. The poor results of this procedure are due to the absence of effects on ET dysfunction. Pneumococcal vaccination has little beneficial effects on recurrent AOM and its use in infants needs further studies. Treatment with amoxicillin is indicated in all children younger than 2 years with a first episode of AOM presenting with redness and bulging of the tympanic membrane. Combined amoxicillin and clavulanic acid should be given in patients with beta-lactamase-producing bacteria. The duration of treatment is estimated to be at least 10 days depending on the findings by pneumo-otoscopy and tympanometry. Bacterial and viral testing of the nasopharyngeal aspirate is highly recommended particularly in children in day care centres as well as for regular follow-up. The high recurrence rate is due to the long-lasting dysfunction of the eustachian tube and the immune immaturity of children less than 2 years of age.

The Moraxella catarrhalis autotransporter McaP is a conserved surface protein that mediates adherence to human epithelial cells through its N-terminal passenger domain

The protein McaP was previously shown to be an adhesin expressed by the Moraxella catarrhalis strain O35E, which also displays esterase and phospholipase B activities (J. M. Timpe et al., Infect. Immun. 71:4341-4350, 2003). In the present study, sequence analysis suggests that McaP is a conventional autotransporter protein that contains a 12-stranded beta-barrel transporter module (amino acids [aa] 383 to 650) linked to a surface-exposed passenger domain exhibiting lipolytic activity (aa 62 to 330). An in-frame deletion removing most of this predicted N-terminal passenger domain was engineered, and Escherichia coli expressing the truncated McaP protein exhibited greatly reduced adherence to A549 human lung epithelial cells compared to E. coli expressing wild-type McaP. Site-directed mutagenesis of a serine residue at position 62 of McaP, predicted to be important for the lipolytic activity of the protein, resulted in loss of hydrolysis of p-nitrophenyl ester of caproate. E. coli expressing this mutated McaP, however, adhered to A549 monolayers at levels greater than recombinant bacteria expressing the wild-type adhesin. These results indicate that the predicted passenger domain of McaP is involved in both the binding and the lipolytic activity of the molecule and demonstrate that the adhesive properties of McaP do not require its lipolytic activity. Sequence analysis of mcaP from eight Moraxella catarrhalis strains revealed that the gene product is highly conserved at the amino acid level (98 to 100% identity), and Western blot analysis demonstrated that a panel of 16 isolates all express McaP. Flow cytometry experiments using antibodies raised against various portions of McaP indicated that its predicted passenger domain as well as transporter module contain surface-exposed epitopes. In addition to binding to the surface of intact bacteria, these antibodies were found to decrease adherence of M. catarrhalis to A549 human lung cells by up to 47% and to reduce binding of recombinant E. coli expressing McaP by 98%. These results suggest that McaP should be considered as a potential vaccine antigen.

Impact of pneumococcal conjugate vaccine and of reduction of antibiotic use on nasopharyngeal carriage of nonsusceptible pneumococci in children with acute otitis media

BACKGROUND

Penicillin resistance among pneumococci has increased in the past 15 years. The implementation of widespread vaccination with the heptavalent pneumococcal conjugate vaccine (PCV7) and the reduction of inappropriate antibiotic use could help reduce antibiotic resistance.

METHODS

Between September 2001 and June 2004, 89 pediatricians distributed throughout France took part in this prospective study. We obtained 1906 nasopharyngeal swabs for culture from children aged 6 to 24 months with acute otitis media (AOM). At the same time as PCV7 was introduced into the routine immunization schedule, a plan to promote judicious antibiotic use was established. We recorded the frequency of antibiotic use, as well as the dates of immunization with PCV7.

RESULTS

The proportion of PCV7-vaccinated children (> or =1 dose) increased from 8.2% (year 1) to 61.4% (year 3). The proportion of children who received antibiotics within 3 months before enrollment decreased from 51.8% in year 1 to 40.9% in year 3 (P < 0.001). Overall pneumococcal carriage and carriage of PCV7 serotypes decreased during the 3-year period by 16% (P < 0.001) and 35% (P < 0.001), respectively. Rates of highly penicillin resistant strains (PRP) decreased yearly: 15.4%, 10.6%, 6.7% (P < 0.001), respectively. Risks for PRP carriage were 4.2% for immunized children who had not received antibiotics, 8.6% for those vaccinated who also had received antibiotics, 10.3% for unimmunized children who had not received antibiotics, and 16.2% for unimmunized children who had received antibiotics (P < 0.001).

CONCLUSION

Implementation of PCV7, combined with a reduction in antibiotic use, in a country with a high prevalence of antibiotic-resistant pneumococci appears to have a strong impact on the carriage of penicillin nonsusceptible pneumococci in children with AOM.