Serotype distribution in pneumococcal acute otitis media with ruptured tympanic membrane or sepsis in Germany

Incidence of acute otitis media in children < 16 years old in Germany during 2014-2019

BACKGROUND

Acute otitis media (AOM) remains a common infection in children despite the introduction of pneumococcal conjugate vaccines. This study estimated AOM incidence rates (IRs) over time in children < 16 years old in Germany following PCV13 introduction.

METHODS

AOM episodes were identified in the InGef healthcare claims database from 2014-2019 in children aged < 16 years. Each AOM episode was classified as either simple or recurrent. Recurrent AOM was defined as 3 or more episodes identified within a 6-month period; or 4 or more episodes within a 12-month period with at least one episode in the prior 6 months. AOM-related surgical procedures within 12 months and complications within 21 days of an AOM episode were also identified. Annual IRs were calculated as number of episodes/child-years (CY) at risk. 95% Confidence intervals (95%CI) were calculated using the Wilson method. The Mann-Kendall test was used to assess trends over time.

RESULTS

Between 2014 and 2019, the study population comprised 916,805 children with 327,726 AOM episodes, of which 15% (49,011) of all episodes were identified as recurrent AOM and 85% (278,715) as simple AOM. There were significant declines in AOM (p = 0.003) in the study population overall and in all age groups over the study period; from 101 (95%CI 101-102)/1000 CY to 79 (95%CI 78-80)/1000 CY in the total study population, from 209 (95%CI 206-212)/1000 CY to 147 (95%CI 145-150)/1000 CY in < 2-year-olds, from 239 (95%CI 237-242) to 179 (95%CI 177-182)/1000 CY in 2-4-year-olds, and from 50 (95%CI 49-50) to 38 (95%CI 37-39)/1000 CY in 5-15-year-olds. No significant trends were identified for AOM-related surgical procedures over the study period; however, AOM-related complications overall increased (p = 0.003).

CONCLUSION

Between 2014 and 2019, AOM incidence overall declined in children aged 0-15 years in Germany. Over the study period, the incidence of complicated AOM cases increased, however the incidence of AOM-related surgical procedures remained constant. Despite the impact of PCV13, the burden associated with AOM in Germany remains substantial.

Bacterial Spectrum of Spontaneously Ruptured Otitis Media in a 7-Year, Longitudinal, Multicenter, Epidemiological Cross-Sectional Study in Germany

We analyzed middle ear fluid (MEF) and nasopharyngeal swabs (NPS) from spontaneously ruptured acute otitis media (AOM) cases occurring in children under 5 years in Germany. The aim of the study was the assessment of disease burden and bacterial etiology in the era of routine pneumococcal vaccination. Furthermore, we aimed to compare isolates from MEF with isolates from NPS and to analyze the Streptococcus pneumoniae serotype distribution. We analyzed MEF and NPS samples in children 2 months to 5 years for vaccination status, frequency of bacterial strains, serotype/emm-type distribution of S. pneumoniae, Haemophilus influenzae, and Streptococcus pyogenes; and intraindividual correlation between MEF and NPS. From 2008 to 2014, MEF samples were collected from 2,138 subjects of which 2,001 (93.6%) also provided an NPS sample. In 851 of 2,138 MEF samples (39.8%), we identified organisms with confirmed pathogenic potential—S. pyogenes: 315 (14.7%), S. pneumoniae: 170 (8.0%), Staphylococcus aureus: 168 (7.9%), H. influenzae: 133 (6.2%), and Moraxella catarrhalis. Among NPS samples, 1,018 (50.9%) contained S. pneumoniae, 775 (38.7%) H. influenzae, 648 (32.4%) M. catarrhalis, and 344 (17.2%) S. pyogenes. Over the seven study years, the number of AOM patients steadily decreased, while the recruiting base remained constant. S. pneumoniae MEF isolates decreased by 86%, with serotype 3 being the most prevalent (25.7–42.9%). PCV13-non-PCV7-non-3 serotypes reduced to 0%. Among NPS, PCV7 serotypes decreased from 14.1 to 3.7%, PCV10: 17.6 to 3.7%, and PCV13: 55.3 to 25.7%. PCV13-non-PCV7-non-3 serotypes increased in the first 3 years of the study (17.1–22.9%), then decreased to 4.6% in year 7. Non-typeable H. influenzae reduced from 87.1 to 41.7% in MEF and from 91.4 to 54.2% in NPS. MEF and NPS isolates from the same subject were identical for 91.9% of S. pneumoniae, 99.0% of S. pyogenes, and 83.3% of H. influenzae. Among PCV7-vaccinated children, 5.6% had a PCV7 vaccine type in the MEF sample, and among PCV13-vaccinated children, 51.7% had a PCV13 serotype. Among non-vaccinated children, the percentages were 14.8 and 70.4. Pneumococcal conjugate vaccination has impacted the prevalence and etiology of spontaneously ruptured otitis media among children in Germany. Overall case numbers and pneumococcal vaccine type cases have strongly decreased.

Impact of Von Willebrand Factor on Bacterial Pathogenesis

Von Willebrand factor (VWF) is a mechano-sensitive protein with crucial functions in normal hemostasis, which are strongly dependant on the shear-stress mediated defolding and multimerization of VWF in the blood stream. Apart from bleeding disorders, higher plasma levels of VWF are often associated with a higher risk of cardiovascular diseases. Herein, the disease symptoms are attributed to the inflammatory response of the activated endothelium and share high similarities to the reaction of the host vasculature to systemic infections caused by pathogenic bacteria such as Staphylococcus aureus and Streptococcus pneumoniae. The bacteria recruit circulating VWF, and by binding to immobilized VWF on activated endothelial cells in blood flow, they interfere with the physiological functions of VWF, including platelet recruitment and coagulation. Several bacterial VWF binding proteins have been identified and further characterized by biochemical analyses. Moreover, the development of a combination of sophisticated cell culture systems simulating shear stress levels of the blood flow with microscopic visualization also provided valuable insights into the interaction mechanism between bacteria and VWF-strings. In vivo studies using mouse models of bacterial infection and zebrafish larvae provided evidence that the interaction between bacteria and VWF promotes bacterial attachment, coagulation, and thrombus formation, and thereby contributes to the pathophysiology of severe infectious diseases such as infective endocarditis and bacterial sepsis. This mini-review summarizes the current knowledge of the interaction between bacteria and the mechano-responsive VWF, and corresponding pathophysiological disease symptoms.

Epidemiology of pneumococcal diseases in Spain after the introduction of pneumococcal conjugate vaccines

In Spain, the use of pneumococcal conjugate vaccines (PCVs) has led to a decrease in the incidence of vaccine serotypes causing invasive and non-invasive disease in vaccinated and unvaccinated children and adults. Further, the coverage of most of the resistant serotypes by vaccines resulted in an overall decline in antibiotic resistance. As an undesirable effect, there was an increase in the non-vaccine serotypes causing infection, especially serotypes 1, 7F and 19A after PCV7 and serotype 8 after PCV13 approval, this making the beneficial effect of vaccination less apparent. The inclusion of PCVs in childhood vaccination schedules, its approval for use in healthy adults and the increasing number of serotypes covered by the vaccines in development are strong strategies in the fight against pneumococcal disease. Nonetheless, the epidemiology of Streptococcus pneumoniae infections must be still under surveillance to detect new changes, given the high capacity for recombination and adaptability of this always-surprising microorganism.

Bacterial spectrum of spontaneously ruptured otitis media in the era of pneumococcal conjugate vaccination in Germany

Otitis media is a common pediatric disease and the main reason for antibiotic prescription in children. Before implementation of routine childhood pneumococcal vaccination in Germany, serotypes contained in the seven-valent pneumococcal conjugate vaccine (PCV) were among the most frequent pneumococcal serotypes responsible for acute otitis media (AOM). This report describes the first 3 years of a prospective, multicenter, epidemiological cross-sectional study examining the bacteriology of middle ear fluids (MEF) and nasopharyngeal swabs (NPS) of children 2 months to 5 years of age with spontaneously perforated AOM in the era of routine pneumococcal vaccination. MEF was obtained from 963 subjects; NPS from 877. Reported case numbers steeply decreased over the three study years even though the recruiting base remained the same. Among subjects with relevant bacterial growth in their MEF swabs, 113 (11.7%) had Streptococcus pyogenes, 97 (10.1%) Staphylococcus aureus, 88 (9.1%) Streptococcus pneumoniae, 63 (6.5%) Haemophilus influenzae, and 8 (0.8%) Moraxella catarrhalis. S. pneumoniae isolates decreased from 41 (9.3%) in year 1 to 12 (5.7%) in year 3 (p = 0.128). PCV7 serotypes accounted for only 7.9% (n = 7) of isolated pneumococci. Of the 877 subjects with NPS cultures, 465 (53.0%) carried S. pneumoniae, 314 (35.8%) H. influenzae, 292 (33.3%) M. catarrhalis, and 110 (12.5%) S. pyogenes; 79.4% (n = 765) of the children were vaccinated with at least one dose of PCV. Carriage of pneumococci was slightly lower in vaccinated (47.8%) than in unvaccinated (52.7%) children (p = 0.254). PCV7 serotypes were carried by 9.6% of unvaccinated children but by only 4.2% of vaccinated children, resulting in a 56.3% vaccine effectiveness.

CONCLUSIONS

Following universal PCV7 immunization, a clear epidemiological impact of pneumococcal conjugate vaccination was observed as PCV7 serotypes have almost disappeared among AOM.

Microbiological characterization of Streptococcus pneumoniae and non-typeable Haemophilus influenzae isolates as primary causes of acute otitis media in Bulgarian children before the introduction of conjugate vaccines

Background

Pneumococcal and Haemophilus influenzae type b (Hib) vaccines were introduced in our national immunisation program in April 2010. The aims of this retrospective, laboratory-based study were to determine the serotypes and antibiotic resistance of Streptococcus pneumoniae and H. influenzae isolates from middle ear fluid (MEF) collected before the introduction of immunization.

Methods

S. pneumoniae (n = 128) and H. influenzae (n = 40) strains isolated from MEF of children with AOM between 1994 and 2011 were studied. MICs were determined by a microdilution assay. Serotyping of S. pneumoniae was done by Quellung method and PCR capsular typing was used for H. influenzae. Macrolide resistance genes were detected by PCR for erythromycin resistant S. pneumoniae (ERSP). DNA sequencing of ftsI gene was performed for ampicillin nonsusceptible H. influenzae.

Results

The most common serotypes found among children with pneumococcal AOM were 19 F (20.3%), 6B (15.6%), and 19A (10.9%). The potential coverage rates by the PCV7, PCV10 and PCV13 of children aged < 5 years were 63.6%, 66.4% and 85.5%, respectively. Reduced susceptibility to oral penicillin was seen in 68.1%; resistance to erythromycin was 46.9%. We found erm(B) gene in 56.7% of the ERSP, mef(E) gene in 25%; 15% harbored both genes erm(B) + mef(E) and 3.3% had mutations of L4 ribosomal protein. Of the 40 H. influenzae isolates 97.5% were nontypeable. Nonsusceptibility to ampicillin occurred in 25%. Ampicillin resistance groups were: β-lactamase-positive ampicillin resistant (BLPAR) strains (10%), β-lactamase-negative ampicillin resistant (BLNAR) strains (12.5%) and β-lactamase-positive amoxicillin-clavulanate resistant (BLPACR) strains (2.5%). Among BLNAR and BLPACR most of the isolates (5/6) belonged to group II, defined by the Asn526Lys substitution.

Conclusions

The levels of antibiotic resistance among S. pneumoniae and H. influenzae causing severe AOM in children are high in our settings. The existence of multidrug-resistant S. pneumoniae serotype 19A is of particular concern. The rate of BLNAR and BLPACR strains among H. influenzae isolates was 15%.

Identification and characterization of the bacterial etiology of clinically problematic acute otitis media after tympanocentesis or spontaneous otorrhea in German children

Background

Acute Otitis Media (AOM) is an important and common disease of childhood. Bacteria isolated from cases of clinically problematic AOM in German children were identified and characterized.

Methods

In a prospective non-interventional study in German children between 3 months and less than 60 months of age with Ear, Nose and Throat Specialist –confirmed AOM, middle ear fluid was obtained by tympanocentesis (when clinically indicated) or by careful sampling of otorrhea through/at an existing perforation.

Results

In 100 children with severe AOM, Haemophilus influenzae was identified in 21% (18/21, 85.7% were non-typeable [NTHi]), Streptococcus pneumoniae in 10%, S. pyogenes in 13% and Moraxella catarrhalis in 1%. H. influenzae was the most frequently identified pathogen in children from 12 months of age. H. influenzae and S. pneumoniae were equally prevalent in children aged 3–11 months, but S. pyogenes was most frequently isolated in this age group. NTHi AOM disease appeared prevalent in all ages.

Conclusions

NTHi, S. pneumoniae and S. pyogenes are implicated as important causes of complicated AOM in children in Germany. NTHi disease appears prevalent in all ages. The impact of vaccination to prevent NTHi and S. pneumoniae AOM may be substantial in this population and is worth investigating.

Regulation of virulence gene expression resulting from Streptococcus pneumoniae and nontypeable Haemophilus influenzae interactions in chronic disease

Chronic rhinosinusitis (CRS) is a common inflammatory disease of the sinonasal cavity mediated, in part, by polymicrobial communities of bacteria. Recent molecular studies have confirmed the importance of Streptococcus pneumoniae and nontypeable Haemophilus influenzae (NTHi) in CRS. Here, we hypothesize that interaction between S. pneumoniae and NTHi mixed-species communities cause a change in bacterial virulence gene expression. We examined CRS as a model human disease to validate these polymicrobial interactions. Clinical strains of S. pneumoniae and NTHi were grown in mono- and co-culture in a standard biofilm assay. Reverse transcriptase real-time PCR (RTqPCR) was used to measure gene expression of key virulence factors. To validate these results, we investigated the presence of the bacterial RNA transcripts in excised human tissue from patients with CRS. Consequences of physical or chemical interactions between microbes were also investigated. Transcription of NTHi type IV pili was only expressed in co-culture in vitro, and expression could be detected ex vivo in diseased tissue. S. pneumoniae pyruvate oxidase was up-regulated in co-culture, while pneumolysin and pneumococcal adherence factor A were down-regulated. These results were confirmed in excised human CRS tissue. Gene expression was differentially regulated by physical contact and secreted factors. Overall, these data suggest that interactions between H. influenzae and S. pneumoniae involve physical and chemical mechanisms that influence virulence gene expression of mixed-species biofilm communities present in chronically diseased human tissue. These results extend previous studies of population-level virulence and provide novel insight into the importance of S. pneumoniae and NTHi in CRS.