The Epidemiology of Childhood Pneumococcal Disease in the United States in the Era of Conjugate Vaccine Use

ABO-incompatible heart transplantation-evolution of a revolution

In the 1990s, neonates born with severe congenital heart disease faced more than 50% mortality awaiting an ABO-compatible (ABOc) transplant donor. This desperate situation, together with knowledge of gaps in the adaptive immune system in early childhood, led to the clinical exploration of intentional ABO-incompatible (ABOi) heart transplantation. In 2001, West et al. reported the first series of 10 infants in Canada. Since then, consideration of ABOi heart donors has become the standard of care for children awaiting transplantation in the first few years of life, resulting in reduced wait times and better organ utilization with noninferior post-transplant outcomes compared to ABOc recipients. This state-of-the-art review discusses the clinical development and evolution, underlying and resulting immunological aspects, current challenges, and future directions of ABOi heart transplantation.

Clinical management of fever in children in Brazil: practical recommendations from an expert panel

The objective of this study was to answer several questions related to the assessment and treatment of fever, as well as other controversies that exist during its management in pediatric patients. First, an advisory board with medical experts was conducted to discuss the clinical journey of these patients, considering the main challenges and possible solutions. After this discussion, a non-systematic literature review was performed, between November 2019 and January 2020, to collect the most relevant evidence available in the scientific databases MEDLINE, Lilacs, and SciELO. A narrative review was carried out based on scientific evidence and on extensive experience of experts in clinical practice. The experts developed a set of recommendations and clarifications about the assessment of the severity of fever in pediatrics, the need for treatment and the choice of the most appropriate antipyretic. The most common controversies in the management of fever in pediatric patients were also addressed, such as alternating antipyretics, persistent fever, and dose equivalence. In primary management of pediatric patients, fever should be seen as a relevant symptom that requires treatment with antipyretics in potentially more complex or severe cases, when it causes discomfort to children or is associated with infectious diseases.

Association of Bacteremia with Vaccination Status in Children Aged 2 to 36 Months

OBJECTIVE

To determine the association between bacteremia and vaccination status in children aged 2-36 months presenting to a pediatric emergency department.

STUDY DESIGN

Retrospective cohort study of children aged 2-36 months with blood cultures obtained in the pediatric emergency department between January 2013 and December 2017. The exposure of interest was immunization status, defined as number of Haemophilus influenzae type B (Hib) and Streptococcus pneumoniae vaccinations, and the main outcome positive blood culture. Subjects with high-risk medical conditions were excluded.

RESULTS

Of 5534 encounters, 4742 met inclusion criteria. The incidence of bacteremia was 1.5%. The incidence of contaminated blood culture was 5.0%. The relative risk of bacteremia was 0.79 (95% CI 0.39-1.59) for unvaccinated and 1.20 (95% CI 0.52-2.75) for undervaccinated children relative to those who had received age-appropriate vaccines. Five children were found to have S pneumoniae bacteremia and 1 child had Hib bacteremia; all of these subjects had at least 3 sets of vaccinations. No vaccine preventable pathogens were isolated from blood cultures of unvaccinated children. We found no S pneumoniae or Hib in children 2-6 months of age who were not fully vaccinated due to age (95% CI 0-0.13%) and the contamination rate in this group was high compared with children 7-36 months (6.6% vs 3.7%).

CONCLUSIONS

Bacteremia in young children is an uncommon event. Contaminated blood cultures were more common than pathogens. Bacteremia from S pneumoniae or Hib is uncommon and, in this cohort, was independent of vaccine status.

Interaction of Macrophages and Cholesterol-Dependent Cytolysins: The Impact on Immune Response and Cellular Survival

Cholesterol-dependent cytolysins (CDCs) are key virulence factors involved in many lethal bacterial infections, including pneumonia, necrotizing soft tissue infections, bacterial meningitis, and miscarriage. Host responses to these diseases involve myeloid cells, especially macrophages. Macrophages use several systems to detect and respond to cholesterol-dependent cytolysins, including membrane repair, mitogen-activated protein (MAP) kinase signaling, phagocytosis, cytokine production, and activation of the adaptive immune system. However, CDCs also promote immune evasion by silencing and/or destroying myeloid cells. While there are many common themes between the various CDCs, each CDC also possesses specific features to optimally benefit the pathogen producing it. This review highlights host responses to CDC pathogenesis with a focus on macrophages. Due to their robust plasticity, macrophages play key roles in the outcome of bacterial infections. Understanding the unique features and differences within the common theme of CDCs bolsters new tools for research and therapy.

ABO-incompatible heart transplantation

PURPOSE OF REVIEW

ABO-incompatible (ABOi) heart transplantation (HTx) in young children has evolved from an experimental approach to a standard allocation option in many countries. Clinical and immunological research in ABOi transplantation has revealed insight into the immature immune system and its role in superior graft acceptance in childhood and antigen-specific tolerance.

RECENT FINDINGS

Multicenter experience has confirmed equal actuarial survival, freedom from rejection, and graft vasculopathy comparing ABOi with ABO-compatible HTx. Observations of reduced antibody production and B-cell immunity toward the donor blood group have been confirmed in long-term follow-up. Mechanisms contributing to tolerance in this setting involve the interplay between B-cells and the complement system and the development of B-cell memory. Better characterization of the ABH polysaccharide antigens has improved diagnostic methods and clinical assessment of blood group antibodies. Boundaries regarding age, immune maturity, and therapeutic interventions to extend the applicability of ABOi HTx have been explored and resulted in data that may be useful for HTx patients beyond infancy and ABOi transplantation of other organs. Tolerance of ABH antigens possibly extends to HLA response.

SUMMARY

The review provides insight into the clinical evolution of ABOi HTx and associated immunologic discoveries. Current experiences and boundaries are discussed together with recent and potential future developments for utilization in other patient and age groups.

Dynamic capsule restructuring by the main pneumococcal autolysin LytA in response to the epithelium

Bacterial pathogens produce complex carbohydrate capsules to protect against bactericidal immune molecules. Paradoxically, the pneumococcal capsule sensitizes the bacterium to antimicrobial peptides found on epithelial surfaces. Here we show that upon interaction with antimicrobial peptides, encapsulated pneumococci survive by removing capsule from the cell surface within minutes in a process dependent on the suicidal amidase autolysin LytA. In contrast to classical bacterial autolysis, during capsule shedding, LytA promotes bacterial survival and is dispersed circumferentially around the cell. However, both autolysis and capsule shedding depend on the cell wall hydrolytic activity of LytA. Capsule shedding drastically increases invasion of epithelial cells and is the main pathway by which pneumococci reduce surface bound capsule during early acute lung infection of mice. The previously unrecognized role of LytA in removing capsule to combat antimicrobial peptides may explain why nearly all clinical isolates of pneumococci conserve this enzyme despite the lethal selective pressure of antibiotics.

Pneumococci produce a carbohydrate capsule that protects them against components of the host immune system but sensitizes them to host antimicrobial peptides. Here, Kietzman et al. show that pneumococci respond to antimicrobial peptides by capsule shedding, which requires the main autolysin LytA.

Nasopharyngeal Carriage, Capsular and Molecular Serotyping and Antimicrobial Susceptibility of Streptococcus pneumoniae among Asymptomatic Healthy Children in Egypt

Streptococcus pneumoniae is a major cause of childhood morbidity and mortality worldwide with increasing antimicrobial resistance. 600 randomly chosen asymptomatic healthy children aged 2-60 months attending Alexandria University Children's Hospital were evaluated for prevalence of nasopharyngeal (NP) carriage of S. pneumoniae. Prevalence of NP carriage was 29.2% (n = 175/600) Capsular serotyping was done using Quellung reaction. Vaccine covered serotypes (VST) represented 67.4% while non-vaccine serotypes (NVST) were 32.6%. The most common VST isolated were 19F (24.6%), 6B (14.3%) and 6A (10.9%). Confirmation of serotyping was performed by multiplex PCR which showed 100% concordance with the Quellung reaction. Antimicrobial susceptibility testing showed penicillin non-susceptibility of 15% (using non-meningitis penicillin MIC breakpoints) and 55% (using meningitis penicillin MIC breakpoints). Highest resistance was found in sulphamethoxazole-trimethoprim (55%), tetracyclins (49%), erythromycin (40%) and clindamycin (25%). This study revealed the epidemiological importance to evaluate regularly the prevalence, serotypes and the increasing antimicrobial resistance of S. pneumoniae in the community.

Mucosal immunization with the live attenuated vaccine SPY1 induces humoral and Th2-Th17-regulatory T cell cellular immunity and protects against pneumococcal infection

Mucosal immunization with attenuated vaccine can protect against pneumococcal invasion infection, but the mechanism was unknown. Our study found that mucosal delivery with the live attenuated SPY1 vaccine strain can confer T cell- and B cell-dependent protection against pneumococcal colonization and invasive infection; yet it is still unclear which cell subsets contribute to the protection, and their roles in pneumococcal colonization and invasion remain elusive. Adoptive transfer of anti-SPY1 antibody conferred protection to naive μMT mice, and immune T cells were indispensable to protection examined in nude mice. A critical role of interleukin 17A (IL-17A) in colonization was demonstrated in mice lacking IL-17A, and a vaccine-specific Th2 immune subset was necessary for systemic protection. Of note, we found that SPY1 could stimulate an immunoregulatory response and that SPY1-elicited regulatory T cells participated in protection against colonization and lethal infection. The data presented here aid our understanding of how live attenuated strains are able to function as effective vaccines and may contribute to a more comprehensive evaluation of live vaccines and other mucosal vaccines.

Serotype-independent protection against pneumococcal infections elicited by intranasal immunization with ethanol-killed pneumococcal strain, SPY1

The 23-valent polysaccharide vaccine and the 7-valent pneumococcal conjugate vaccine are licensed vaccines that protect against pneumococcal infections worldwide. However, the incidence of pneumococcal diseases remains high in low-income countries. Whole-cell vaccines with high safety and strong immunogenicity may be a favorable choice. We previously obtained a capsule-deficient Streptococcus pneumoniae mutant named SPY1 derived from strain D39. As an attenuated live pneumococcal vaccine, intranasal immunization with SPY1 elicits broad serotype-independent protection against pneumococcal infection. In this study, for safety consideration, we inactivated SPY1 with 70% ethanol and intranasally immunized BALB/c mice with killed SPY1 plus cholera toxin adjuvant for four times. Results showed that intranasal immunization with inactivated SPY1 induced strong humoral and cellular immune responses. Intranasal immunization with inactivated SPY1 plus cholera toxin adjuvant elicited effective serotype-independent protection against the colonization of pneumococcal strains 19F and 4 as well as lethal infection of pneumococcal serotypes 2, 3, 14, and 6B. The protection rates provided by inactivated SPY1 against lethal pneumococcal infection were comparable to those of currently used polysaccharide vaccines. In addition, vaccine-specific B-cell and T-cell immune responses mediated the protection elicited by SPY1. In conclusion, the 70% ethanol-inactivated pneumococcal whole-cell vaccine SPY1 is a potentially safe and less complex vaccine strategy that offers broad protection against S. pneumoniae.

Will there ever be a universal Staphylococcus aureus vaccine?

Developing a universal vaccine for S. aureus is a top priority but to date we have only had failures in human clinical trials. Given the plethora of bacterial virulence factors, broad range of the health of humans at-risk for infections, lack of any information regarding immune effectors mediating protection for any manifestation of S. aureus infection and overall competence of this organism as a colonizer, commensal and pathogen, we may just simply have to accept the fact that we will not get a universal vaccine. Antigenic variation is a major challenge for some vaccine targets and for many conserved targets the organism can easily decrease or even eliminate expression to avoid immune effectors without compromise to infectivity and ability to cause disease. Studies of human immune responses similarly have been unable to identify any clear mediators of immunity and data from such studies can only eliminate those found not to be associated with protection or that might serve as a marker for individuals with a higher level of resistance to infection. Animal studies are not predictive of success in humans and unlikely will be except in hindsight if and when we develop an efficacious vaccine. Successful vaccines for other bacteria based on capsular polysaccharides have not worked to date for S. aureus, and laboratory studies combining antibody to the major capsular serotypes and the other S. aureus surface polysaccharide, poly-N-acetyl glucosamine, unexpectedly showed interference not augmentation of immunity. Potential pathways toward vaccine development do exist but for the foreseeable future will be based on empiric approaches derived from laboratory-based in vitro and animal tests and not on inducing a known immune effector that predicts human resistance to infection.

Antibody to a conserved antigenic target is protective against diverse prokaryotic and eukaryotic pathogens

Microbial capsular antigens are effective vaccines but are chemically and immunologically diverse, resulting in a major barrier to their use against multiple pathogens. A β-(1→6)-linked poly-N-acetyl-d-glucosamine (PNAG) surface capsule is synthesized by four proteins encoded in genetic loci designated intercellular adhesion in Staphylococcus aureus or polyglucosamine in selected Gram-negative bacterial pathogens. We report that many microbial pathogens lacking an identifiable intercellular adhesion or polyglucosamine locus produce PNAG, including Gram-positive, Gram-negative, and fungal pathogens, as well as protozoa, e.g., Trichomonas vaginalis, Plasmodium berghei, and sporozoites and blood-stage forms of Plasmodium falciparum. Natural antibody to PNAG is common in humans and animals and binds primarily to the highly acetylated glycoform of PNAG but is not protective against infection due to lack of deposition of complement opsonins. Polyclonal animal antibody raised to deacetylated glycoforms of PNAG and a fully human IgG1 monoclonal antibody that both bind to native and deacetylated glycoforms of PNAG mediated complement-dependent opsonic or bactericidal killing and protected mice against local and/or systemic infections by Streptococcus pyogenes, Streptococcus pneumoniae, Listeria monocytogenes, Neisseria meningitidis serogroup B, Candida albicans, and P. berghei ANKA, and against colonic pathology in a model of infectious colitis. PNAG is also a capsular polysaccharide for Neisseria gonorrhoeae and nontypable Hemophilus influenzae, and protects cells from environmental stress. Vaccination targeting PNAG could contribute to immunity against serious and diverse prokaryotic and eukaryotic pathogens, and the conserved production of PNAG suggests that it is a critical factor in microbial biology.

Pediatric acute mastoiditis in the post-pneumococcal conjugate vaccine era

OBJECTIVES/HYPOTHESIS

To determine whether the characteristics of acute mastoiditis in children have changed in the post-heptavalent pneumococcal conjugate vaccine (PCV7) era.

STUDY DESIGN

Case series.

METHODS

Clinical data for all patients admitted for acute mastoiditis at an urban tertiary children's hospital from July 1, 1996, to June 30, 2009, were reviewed. Patients with a known immune deficiency or cholesteatoma were excluded. Patients were divided into pre-PCV7 (July 1996 to December 2002; n = 38) and post-PCV7 (January 2003 to June 2009; n = 58) groups. Statistical analyses were used to compare the two groups.

RESULTS

Ninety-six children met the inclusion criteria. There was a 53% increase in admission for acute mastoiditis in the post-PCV7 era. The pre- and post-PCV7 groups had similar demographic features, presenting history, signs and symptoms, laboratory study results, and medical management. Computed tomography scan abnormalities seen in the two groups were similar except for subperiosteal abscess, which was seen more frequently in the post-PCV7 group. Streptococcus pneumoniae was the most common pathogen isolated in both groups. The patients in the post-PCV7 group had shorter hospital stays, despite undergoing more extensive surgery to address their disease.

CONCLUSIONS

The number of acute mastoiditis admissions did not decrease with the widespread use of PCV7. Computed tomography findings and surgical procedures required to address acute mastoiditis indicate that the post-PCV7 group had more advanced disease. S pneumoniae remains the main pathogen in acute mastoiditis, and its nonsusceptibility to penicillin and ceftriaxone may be increasing.

Absence of donor-specific anti-HLA antibodies after ABO-incompatible heart transplantation in infancy: altered immunity or age?

Specific B-cell tolerance toward donor blood group antigens develops in infants after ABO-incompatible heart transplantation, whereas their immune response toward protein antigens such as HLA has not been investigated. We assessed de novo HLA-antibodies in 122 patients after pediatric thoracic transplantation (28 ABO-incompatible) and 36 controls. Median age at transplantation was 1.7 years (1 day to 17.8 year) and samples were collected at median 3.48 years after transplantation. Antibodies were detected against HLA-class I in 21 patients (17.2%), class II in 18 (14.8%) and against both classes in 10 (8.2%). Using single-antigen beads, donor-specific antibodies (DSAs) were identified in six patients (all class II, one additional class I). Patients with DSAs were significantly older at time of transplantation. In patients who had undergone pretransplant cardiac surgeries, class II antibodies were more frequent, although use of homografts or mechanical heart support had no influence. DSAs were absent in ABO-incompatible recipients and class II antibodies were significantly less frequent than in children with ABO-compatible transplants. This difference was present also when comparing only children transplanted below 2 years of age. Therefore, tolerance toward the donor blood group appears to be associated with an altered response to HLA beyond age-related effects.

Evaluating Children with Otitis Media for Bacteremia or Urinary Tract Infection

Background. It is unclear if clinicians evaluate for concurrent bacteremia or UTI in young patients diagnosed with acute otitis media (AOM). Objectives. To describe how often, and under which circumstances, emergency providers investigate for bacteremia or UTI in 2–36 month olds with AOM. Methods. Cases of AOM were analyzed from the 2001–2004 National Hospital Ambulatory Medical Care Survey (NHAMCS)-Emergency Department dataset. Results. AOM was diagnosed in 17% of the 10,847 recorded visits of 2–36 month olds. Of these visits, laboratory testing included: CBC: 7%, Blood culture: 4%, urinalysis or urine culture: 5%, and any of these tests: 9%. Rates of testing for 2–6 month olds with temperature ≥ 38.0 (CBC: 13%, blood culture: 9%, urinalysis or urine culture: 7%, any of the tests: 14%) were not significantly different from testing of patients aged 6–12 months, or 12–36 months (all P > .1). Patients with temperature of ≥39.0 were more likely to have all tests, with the exception of urine investigation, than patients with temperature between 38.0 and 38.9. Conclusions. 17% of 2–36 month old patients seen in the emergency department are diagnosed with AOM. Investigating for bacteremia or UTI in these patients is not routine, even in febrile infants.

Bacterial genome variability and its impact on vaccine design

The majority of currently available successful vaccines induce host responses against antigens that are highly conserved in the targeted pathogens. The diphtheria, tetanus, and pertussis vaccines confer protection by inducing neutralizing antibodies to the conserved bacterial toxins that are the major virulence factors. The Hemophilus influenzae B vaccine induces responses to conserved epitopes in the sugar structure of the bacterial capsular polysaccharide. However, the efficacy of more recently developed vaccines is limited by antigen variation, which also presents a challenge for future vaccine development. This review will explore bacterial genome variability and its impact on vaccine development.

Bloodstream infections: evolution and trends in the microbiology workload, incidence, and etiology, 1985-2006

Information available on bloodstream infection (BSI) is usually restricted to short periods of time, certain clinical backgrounds, or specific pathogens, or is just outdated. We conducted the current prospective study of patients with BSI in a 1750-bed teaching hospital to evaluate workload trends and the incidence and etiology of BSI in a general hospital during the last 22 years, including the acquired immunodeficiency syndrome (AIDS) era. The main outcome measures were laboratory workload, trends in incidence per 1000 admissions and per 100,000 population of different microorganisms, and the impact of the human immunodeficiency virus (HIV) epidemic in the period 1985-2006.From 1985 to 2006 we had 27,419 episodes of significant BSI (22,626 patients). BSI incidence evolved from 16.0 episodes to 31.2/1000 admissions showing an annual increase of 0.83 episodes/1000 admissions (95% confidence interval, 0.61-1.05; p < 0.0001). The evolution of the incidence per 1000 admissions and per 100,000 population of different groups of microorganisms was as follows: Gram positives 8.2 to 15.7/1000 admissions and 66.8 to 138.3/100,000 population; Gram negatives 7.8 to 16.2/1000 admissions and 63.5 to 141.9/100,000 population; anaerobes 0.5 to 1.3/1000 admissions and 4.1 to 11.7/100,000 population; and fungi 0.2 to 1.5/1000 admissions and 1.7 to 12.5/100,000 population. All those differences were statistically significant. We observed the emergence of multiresistant Gram-positive and Gram-negative microorganisms. At least 2484 episodes of BSI (9.1%) occurred in 1822 patients infected with HIV. The incidence of BSI in HIV-infected patients increased from 1985 and reached a peak in 1995 (17.6% of BSI). Since 1995, the decrease was continuous, and in 2006 only 3.9% of all BSI episodes occurred in HIV-positive patients in our institution. We conclude that the BSI workload has increased in modern microbiology laboratories. Gram-positive pathogens have overtaken other etiologic agents of BSI. Our observation shows the remarkable escalation of some resistant pathogens, and the rise and relative fall of BSI in patients with HIV.

Live attenuated Streptococcus pneumoniae strains induce serotype-independent mucosal and systemic protection in mice

Streptococcus pneumoniae is an important human pathogen causing both mucosal (otitis media and pneumonia) and systemic (sepsis and meningitis) diseases. Due to increasing rates of antibiotic resistance, there is an urgent need to improve prevention of pneumococcal disease. Two currently licensed vaccines have been successful in reducing pneumococcal disease, but there are limitations with their use and effectiveness. Another approach for prevention is the use of live attenuated vaccines. Here we investigate the safety and protection induced by live attenuated strains of S. pneumoniae containing combinations of deletions in genes encoding three of its major virulence determinants: capsular polysaccharide (cps), pneumolysin (ply), and pneumococcal surface protein A (pspA). Both the cps and ply/pspA mutants of a virulent type 6A isolate were significantly attenuated in a mouse model of sepsis. These attenuated strains retained the ability to colonize the upper respiratory tract. A single intranasal administration of live attenuated vaccine without adjuvant was sufficient to induce both systemic and mucosal protection from challenge with a high dose of the parent strain. Immunization with cps mutants demonstrated cross-protective immunity following challenge with a distantly related isolate. Serum and mucosal antibody titers were significantly increased in mice immunized with the vaccine strains, and this antibody is required for full protection, as microMT mice, which do not make functional, specific antibody, were not protected by immunization with vaccine strains. Thus, colonization by live attenuated S. pneumoniae is a potentially safe and less complex vaccine strategy that may offer broad protection.

Immunization update

Although the development and licensure of new vaccines over the last 2 years has generated a lot of excitement as well as debate, there is a lot more to come. Not discussed in this article. licensure of another long-awaited vaccine albeit for use in adults was that for herpes zoster. The second HPV and rotavirus vaccines are awaiting approval in the US. Next in line are the vaccines both prophylactic as well as therapeutic against HIV. Topics of debate over the new vaccines include discussions amongst practices as to the affordability and cost of the new vaccines as well as the ethical debate amongst lawmakers and the general public regarding the rights and wrongs of compulsory vaccination against HPV. Another ongoing discussion is regarding the availability of approved vaccines. Shortages have been seen with several of the childhood vaccines including heptavalent pneumococcal conjugate vaccine, tetravalent meningococcal conjugate vaccine, hepatitis A vaccine, as well as the ongoing saga with influenza vaccines. Across the globe while the struggle against polio continues, there is encouraging news regarding the reduction in measles-related deaths, particularly in Africa. The last few years have indeed been landmark years in infectious disease research as the search continues for better and safer vaccines globally.

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.

Streptococcus pneumoniae pilus subunits protect mice against lethal challenge

Streptococcus pneumoniae is a major public health threat worldwide. The recent discovery that this pathogen possesses pili led us to investigate their protective abilities in a mouse model of intraperitoneal infection. Both active and passive immunization with recombinant pilus subunits afforded protection against lethal challenge with the S. pneumoniae serotype 4 strain TIGR4.