The role of Mycoplasma in upper respiratory infections

Mycoplasma pneumoniae is a common cause of upper and lower respiratory tract infections. Pneumonia is the most clinically important manifestation, but tracheobronchitis and various nonspecific upper respiratory tract symptoms are more typically seen in clinical settings. M. pneumoniae can cause pharyngitis with or without concomitant lower respiratory tract involvement, but it is less commonly detected in other upper respiratory conditions such as otitis media, sinusitis, and the common cold. A variety of methods exist for laboratory diagnosis of M. pneumoniae infection, including culture, serology, and the polymerase chain reaction assay, but each has limitations. This article provides a summary of recent studies that have evaluated the role of M. pneumoniae in upper respiratory tract infections; a brief discussion of its cell biology, pathogenic mechanisms, and epidemiology; and recommendations for laboratory diagnosis and management.     

Otitis media among children in day care: epidemiology and pathogenesis

Acute and persistent middle-ear effusions are the most common complications of upper respiratory illness in young children. Knowledge of the impact of day care attendance on the incidence and prevalence of these conditions is not as complete as is desirable. Several studies suggest that the incidence of acute otitis media may be higher in children who attend group and home day care, but from these studies it is difficult to assess the magnitude of the risk of otitis media related to day care attendance. Research by Danish investigators indicates that the point prevalence of middle-ear effusion may be two to four times higher in children younger than four years old attending group day care centers than in children cared for at home or in smaller home day care settings. Recent epidemiologic and laboratory investigations have begun to elucidate the role of viral infections and of virus-bacteria interaction in the pathogenesis of acute middle-ear effusion. A thorough understanding of the relationship between day care attendance and the occurrence of otitis media with effusion would require studies that quantify the differential risk of disease in different care settings and that relate illness risk to the epidemiology of both viral and bacterial infections of the upper respiratory tract in the different environments. This type of research has not yet been conducted.     

What Does Tympanostomy Tube Placement in Children Teach Us About the Association Between Atopic Conditions and Otitis Media?

Otitis media is the most common infection second only to viral upper respiratory infection in the outpatient setting. Tympanostomy tube insertion (TTI) is the most common ambulatory surgical procedure in the USA. While many risk factors for otitis media have been identified, atopic conditions have been underrecognized as risk factors for recurrent and persistent otitis media. Given that asthma and other atopic conditions are the most common chronic conditions during childhood, it is worth examining the association between atopic conditions and risk of otitis media, which can provide insight into how atopic conditions influence the risk of microbial infections. This paper focuses its discussion on otitis media; however, it is important that the association between atopic conditions and risk of otitis media be interpreted in the context of the association of atopic conditions with increased risks of various microbial infections.     

Pharmacotherapy to prevent the complications of allergic rhinitis.

Allergic rhinitis is an immunologic disease with effects that extend beyond the symptoms that occur subsequent to allergen exposure. A reduced quality of life and medical conditions such as asthma, sinusitis and otitis media are well recognized complications of allergic rhinitis. Craniofacial abnormalities, nasal ployps, and respiratory infections have been linked to allergic rhinitis, but the evidence is conflicting. This article reviews the complications of allergic rhinitis, their prevalences, possible mechanisms for their relationship to allergic rhinitis, and the prevention of these complications via pharmacologic treatment of allergic rhinitis.     

Pneumococcal Disease and its Prevention with Polyvalent Pneumococcal Polysaccharide Vaccines—A Review

Summary: Polyvalent pneumococcal polysaccharide vaccines have been shown to be safe, immunogenic and efficacious and are becoming available for use in patients at high risk of developing pneumococcal infections.
Precise estimates of the role of the pneumococcus in human respiratory disease are difficult to obtain, as this organism is also a frequent commensal of the upper respiratory tract; and as the optimal techniques for the identification and proof of its role are not widely used. Nevertheless, the pneumococcus remains the principal cause of adult pneumonia and paediatric otitis media, and is also an important cause of death from bacteremia and meningitis.
At present it seems likely that in Australia these vaccines will be most useful amongst people over the age of 50 years, those with chronic systemic disease, alcoholics, splenectomized individuals and disadvantaged groups such as Australian aborigines, all of whom are particularly susceptible to pneumo-coccal bacteremia which has a considerable mortality rate. The possibility of preventing pneumococcal otitis media in childhood is still being evaluated. Studies of the role played by the various pneumococcal serotypes in Australian populations are urgently needed.     

Upper respiratory tract infections in general practice: diagnosis,antibiotic prescribing,duration of symptoms and use of diagnostic tests

A diagnosis/antibiotic prescribing study was performed in 5 counties in Sweden for 1 week in November 2000. As part of this study, the characteristics and clinical management of patients with upper respiratory tract infections (n = 2899) in primary care were analyzed. Almost half of the patients were aged < 15 y and one-fifth of the patients consulted out of hours. Of all patients seeking primary care for upper respiratory tract infections, 56.0% were prescribed an antibiotic. Almost all patients who were given the diagnoses streptococcal tonsillitis, acute otitis media or acute sinusitis were prescribed antibiotics, compared to 10% of patients with common cold or acute pharyngitis. The most frequently prescribed antibiotic was penicillin V (79.2%) and this was even more pronounced out of hours, when the diagnoses otitis media and streptococcal tonsillitis were more frequently used. In patients with common cold and acute pharyngitis, the percentage who received antibiotics increased with increasing length of symptoms and increasing CRP levels. In patients with acute pharyngitis or streptococcal tonsillitis, antibiotics were prescribed less frequently provided streptococcal tests were performed. The management of patients with upper respiratory tract infections in general practice seems to be in good agreement with current Swedish guidelines. However, the study indicates some areas for improvement. The diagnosis of acute sinusitis seems to have been overestimated and used only to justify antibiotic treatment.     

Otitis Media in Infancy and the Development of Asthma and Atopic Disease

Otitis media is a frequent respiratory infection of early childhood and it is important to fully understand the long-term complications and sequelae. Literature examining otitis media in early childhood and subsequent development of atopic disease is sparse despite there being vast literature on the association between respiratory infections and atopic disease. Current data support the hypothesis that otitis media infections in early life, especially frequent or severe infections, influence the developing immune system, resulting in increased risk for asthma. Recent findings have also reported an association between otitis media and eczema. Atopic children and those with a family history of atopy appear to be at greater risk. Future work should investigate the specific mechanisms involved. It is possible that vaccines and preventive strategies aimed at reducing the burden of otitis media could also reduce the burden of childhood asthma and atopic disease.     

Antibiotic resistance of oral anaerobic bacteria and their effect on the management of upper respiratory tract and head and neck infections

Anaerobes of oral origin are common in chronic upper respiratory tract and other head and neck infections. Anaerobes are the predominant components of the normal human oropharyngeal flora, and are therefore a common cause of bacterial infections of the upper respiratory tract that are of endogenous origin. These bacteria can be isolated in chronic otitis media, sinusitis, and tonsillitis, and their complications. Anaerobes also predominate in deep oral and neck infections and abscesses. Their isolation requires appropriate methods of collection, transportation, and cultivation of specimens. In addition to their active pathogenic role in these infections, many anaerobes express an indirect effect through their ability to produce the enzyme beta-lactamase. This enables these organisms to shield non-beta-lactamase-producing bacteria (BLPB) from penicillins. Inadequate therapy against BLPB may lead to clinical failures. Treatment of anaerobic infection is complicated by their slow growth, their polymicrobial nature, and the growing resistance of anaerobic bacteria to antimicrobials. Antimicrobial therapy is often the only form of therapy needed, whereas in other instances it is an important adjunct to a surgical approach. Because anaerobes generally are isolated mixed with aerobic organisms, therapy should provide for adequate coverage of both types of pathogens.     

The role of anaerobic bacteria in upper respiratory tract and other head and neck infections

Anaerobes are common pathogens in chronic upper respiratory tract and head and neck infections. They can be recovered in chronic otitis media and sinusitis, play a role in tonsillitis, and predominate in complications of these infections, causing deep oral and neck infections and abscesses. In addition to their direct pathogenicity, they play an indirect role through the production of the enzyme β-lactamase, “shielding” non-β-lactamase-producing bacteria from penicillins. Failure to provide adequate therapy against anaerobes may lead to clinical failures. Management of anaerobic infection is complicated by the slow growth of these organisms, by their polymicrobial nature, and by their growing resistance to antimicrobials. Antimicrobials are often the only form of therapy needed, but surgical approach is needed in some cases. Because anaerobes often are mixed with aerobic organisms, the antimicrobials given should provide adequate coverage against all pathogens.     

Viral otitis media

Acute otitis media (AOM) and viral upper respiratory tract infections (URIs) represent the two most common diseases affecting the human population, and account for substantial patient morbidity and health care costs. Epidemiologic and experimental studies suggest that URIs play a causal role in the pathogenesis of AOM. Specifically, viruses can either invade the middle ear (ME) space and invoke an inflammatory response that culminates in ME effusion formation and consequent symptoms, or URIs might cause eustachian-tube dysfunction, resulting in negative ME pressures and subsequent ME effusion (hydrops ex vacuo theory). The events responsible for the inflammatory response of the human ME following viral exposure have not been well characterized. Although many prophylactic and therapeutic interventions have been evaluated for the treatment of AOM, the information on virusspecific interventions is sparse. In this article, the epidemiology, pathogenesis, diagnosis, and management of viral otitis media are reviewed.     

Air pollution and Otitis media: A review of evidence from epidemiologic studies

Otitis media (main types: acute otitis media and otitis media with effusion) is one of the most common childhood infections, particularly before the age of 3 years. The main causes are viral and/or bacterial ear infections, commonly accompanied by or following upper respiratory tract infection. Besides these infections, other risk factors, such as male sex, young age, genetic predisposition, low socioeconomic status, low vitamin A and C intake, and bottle-feeding are discussed. There is indication that exposure to environmental tobacco smoke is a major environmental risk factor, although additional effects of the exposure to ambient air pollutants is uncertain. Although some studies reported statistically significant increased risk for otitis media in children with high exposure to ambient air pollutants, the risks were not consistent among the studies. Owing to the scarcity of available data, far-reaching conclusions cannot be drawn yet. However, the evidence of an increased risk for environmental tobacco smoke exposure and identified increased risk for ambient air pollution exposure in some studies should stimulate future research using otitis media as one of the major outcomes in air pollution epidemiology.     

The Use of Probiotics in Head and Neck Infections

Recurrent episodes of infections in the upper respiratory tract are very common. The pathogenesis behind these recurrences is still not well understood, but much attention has been paid to the adherence of the microorganisms to epithelial structures and to the protective function of the normal bacterial flora (bacterial interference). Thus, in vitro as well as in vivo studies have shown that both aerobic and anaerobic bacteria of the normal flora in the upper respiratory tract can hinder the growth of pathogens and the establishment of a renewed infection. Studies have shown that lack of interfering bacteria facilitates recurrence of these diseases. Recolonization with interfering alpha-streptococci has been performed successfully in acute streptococcal pharyngotonsillitis, as well as in acute otitis media. The number of recurrences has significantly been lowered in these diseases after recolonization with alpha-streptococci, which is the dominating normal bacteria in the upper respiratory tract. Several mechanisms have been proposed to be responsible for this interaction, such as competition of the adhering sites at the epithelial cells, production of hydrogen peroxide, competition for nutritients, and production of specific growth inhibiting factors such as bacteriocins. Other human components like lactoferrin are also important in the defense against microorganisms, and are important parts of the unspecific and specific immune system.     

Nontypeable Haemophilus influenzae (NTHi) epidemiology

While most systemic pediatric Haemophilus influenzae infections are caused by the type b strain (Hib), nontypeable H. influenzae: (NTHi) has been considered a respiratory tract pathogen common in local infection such as acute otitis media, acute pneumonia, secondary chronic respiratory disease and other otorhinolaryngologic infections. Recent findings show, however, that NTHi also causes invasive infections such as meningitis, bacteremia, and lower respiratory tract infections such as pneumonia. A review of NTHi epidemiology from the 1990s onward shows that NTHi causes significant morbidity in pediatric acute otitis media, sinusitis, conjunctivitis and lower respiratory diseases such as pneumonia in Japan. This summary also reviews the worldwide influence of Streptococcus pneumoniae and Hib vaccines on causative pathogens, and several studies about increasing incidence of invasive infections due to NTHi. This review also touches on the emergence of treatment- and drug-resistant H. influenzae, which are now major public health challenges. As a cause of bacterial pediatric infection, NTHi is an important target for prevention.     

Sex differences in the incidence and severity of respiratory tract infections

Sex is a significant epidemiological factor for several diseases. However, the role of sex in the development and outcome of various infections has not been extensively studied with the notable exception of urinary tract infections. We searched in the PubMed database to identify articles that could provide relevant data regarding sex differences in the incidence and severity of respiratory tract infections (RTIs). We extracted data from 84 relevant studies that provided information regarding sex differences in the incidence and severity of RTIs. Females are more commonly affected with infections of the upper respiratory tract, specifically sinusitis, tonsillitis, and otitis externa. On the other hand, males are more commonly affected with otitis media, croup, and most important, lower RTIs. It is also evident from the reviewed evidence that the course of most RTIs is more severe in males than in females, leading to higher mortality in males, especially in community-acquired pneumonia. In conclusion, the available data suggest that males are more susceptible than females to most types of RTIs in all age groups (adults and children). Overall, it seems that males develop RTIs more frequently than females, except for sinusitis, otitis externa, and probably tonsillitis. Anatomic, lifestyle, behavioural, and socioeconomic differences between males and females may explain the observed findings. The role of sex hormones in the regulation of the immune system may also contribute to the reported sex differences in the incidence and severity of the various types of RTIs, especially in adolescents and adults.     

The Role of <Emphasis Type="Italic">Helicobacter pylori</Emphasis> in Upper Respiratory System Infections: Is it More Than Colonization?

Helicobacter pylori (HP) is recognized as a common chronic human bacterial infection and is the most common cause of gastritis. Recent studies suggest an increased HP prevalence in patients with various extra-digestive inflammatory diseases. Since many respiratory diseases are characterized by chronic inflammation as well as increased immune response, and HP may enter the nasopharyngeal cavity by gastroesophageal reflux, an association between respiratory disorders and HP infection has been suggested. Several studies discover HP in clinical samples from the patients with upper respiratory system infections. Even some of them revealed a relief after the treatment directed to HP eradication. However some studies do not support this theory and whether this association means a definite proof of a causal relationship between HP and respiratory diseases needs to be clarified. In this study, we aimed to review the reports about the role of HP in upper respiratory system infections.     

Common variable immunodeficiency (CVID) presenting with malabsorption due to giardiasis.

Common variable immunodeficiency is characterized with B-cell and T-cell dysfunction and hypogammaglobulinemia. Recurrent bacterial infections, such as otitis media, chronic sinusitis and recurrent pneumonia due to diminished immunoglobulin (Ig) levels and impaired antibody production are frequently observed in common variable immunodeficiency. Almost half of the patients with common variable immunodeficiency have problems related to the gastrointestinal system. A 39-year-old woman was referred to our department with the complaint of chronic diarrhea. She had experienced diarrhea without mucus or blood in the last year and had lost 30 kg. In her medical history, she had suffered from recurrent upper and lower respiratory infections like sinusitis, otitis media and pneumonia since childhood. Serum immunoglobulin levels were low. There were no parasites or ova in her stool examinations. Esophagogastroduodenoscopy detected widespread macroscopic nodular appearance on duodenum, and biopsies from the duodenum revealed giardiasis invading the tissue. She was diagnosed as common variable immunodeficiency. After metronidazole therapy and intravenous immunoglobulin infusion was started, her diarrhea attacks ceased and she regained her normal weight. Common gastrointestinal system problems in patients with common variable immunodeficiency are lactose intolerance, lymphoid hyperplasia/diffuse lymphoid infiltration, loss of villi and infection, especially with Giardia lamblia. Giardiasis may lead to severe mucosal flattening and sometimes to lymphoid hyperplasia at the lamina propria of the duodenum. Medical history should be evaluated carefully regarding recurrent respiratory infections. In such cases with chronic diarrhea, common variable immunodeficiency should be kept in mind as a possible cause.