Rhinovirus in acute otitis media

Streptococcus salivarius Probiotics to Prevent Acute Otitis Media in Children: A Randomized Clinical Trial

Importance

New approaches for the prevention of acute otitis media (AOM), the most common reason for antibiotic use in children, are needed.

Objective

To assess the efficacy of the Streptococcus salivarius K12 oral probiotics in the primary prevention of AOM.

Design, Setting, and Participants

This double-blind, randomized placebo-controlled clinical trial was conducted from August 1, 2020, to May 31, 2021, at 50 day care centers in the Oulu region of Finland. A total of 827 children aged 1 to 6 years attending day care were included. The exclusion criteria consisted of ongoing antimicrobial prophylaxis or immunodeficiency. The follow-up time was 6 months and was completed on May 31, 2021. Data were analyzed from October 24, 2022, to September 16, 2023, based on intention to treat.

Intervention

Eligible participants were randomly allocated to receive 1 daily dose of a S salivarius K12 product or placebo every evening for 6 months. A daily dose was defined as 1 sachet of soluble oral powder for children younger than 3 years or 1 chewable tablet for children 3 years or older containing 1 × 109 colony-forming units of S salivarius K12.

Main Outcomes and Measures

The primary outcome was the proportion of children with at least 1 episode of AOM requiring antimicrobial therapy within 6 months of randomization. All physician visits and purchases of antimicrobial drugs were retrieved from the electronic national medical record and prescription register. The primary outcome was met if the legal guardian had purchased an antimicrobial prescription for AOM.

Results

A total of 827 children with a mean (SD) age of 4.1 (1.6) years (433 boys [52.4%]) were randomized to S salivarius K12 oral products (n = 413) or placebo (n = 414). Thirty-four children (8.2%) in the S salivarius group and 24 children (5.8%) in the placebo group experienced at least 1 episode of AOM requiring antimicrobial therapy during the 6-month follow-up period (relative risk, 1.42 [95% CI, 0.86-2.34]; proportion difference, -2.44% [95% CI, -5.94% to 1.09%]; P = .17). Time to first AOM episode did not differ between the groups (174 [95% CI, 171-177] days in the S salivarius group vs 176 [95% CI, 173-179] days in the placebo group; P = .18).

Conclusions and Relevance

In this randomized placebo-controlled clinical trial, the daily use of the S salivarius K12 products for 6 months did not reduce the occurrence of AOM. New approaches for primary prevention of AOM among children are needed.

Trial Registration

ClinicalTrialsRegister.eu Identifier: 2020-001076-14.

The role of rhinovirus in children hospitalized for acute respiratory disease, Santa Fe, Argentina

Human rhinoviruses (HRVs) were historically considered upper airway pathogens. However, they have recently been proven to cause infections in the lower respiratory tract, resulting in hospitalization of children with pneumonia, bronchiolitis, and chronic pulmonary obstruction. In this report, HRV frequency and seasonality are described together with patient clinical-epidemiological aspects. From a total of 452 surveyed samples, the HRV nucleic acids was detected in 172 (38.1%) and found in every month of the study year. 60% of inpatients with acute respiratory infection (ARI) associated with HRV were under 6 months of age and 31% had a clinical history, being preterm birth and recurrent wheezing the prevailing conditions. The most frequent discharge diagnoses were pneumonia (35.2%), bronchiolitis (32.4%), and bronchitis (12.4%). Fifteen point nine percent of patients required admission into intensive care units. The results obtained in this study demonstrated the association between HRV and children hospitalizations caused by ARI.

Rhinovirus infections in western Sweden: a four-year molecular epidemiology study comparing local and globally appearing types

Human rhinovirus (HRV) is a highly prevalent pathogen and a major cause of acute respiratory tract infection (ARTI). HRV express less seasonality than other viral ARTIs, which typically appear as seasonal epidemics lasting for 1–2 months. The aim of this study was to investigate the seasonal patterns of HRV types over four consecutive years in one geographic region. HRV identified in respiratory samples from 114 patients over a four-year period were analysed by VP4/VP2 sequencing. HRV-A was found in 64, HRV-B in 11 and HRV-C in 37 cases. Overall, 33 different HRV-A types, nine B types and 21 C types were found. As many as 21 of the HRV types appeared during several seasons, with a maximum time-span of four years. Some types appeared during successive seasons and, in some cases, phylogenetic analysis indicated extended periods of circulation locally. Most of the strains were closely related to HRV identified in other parts of the world during the same time period. HRV strains that circulate locally represent many types and seem to reflect that HRV infections are highly globalised. The existence of simultaneous or successive epidemics with different HRV types in combination with the ability of each type to remain in the local population over extended periods of time may contribute to explaining the high rate of HRV infections.

Development of a quantitative real-time nucleic acid sequence-based amplification assay with an internal control using molecular beacon probes for selective and sensitive detection of human rhinovirus serotypes

Evidence demonstrating that human rhinovirus (HRV) disease is not exclusively limited to the upper airways and may cause lower respiratory complications, together with the frequency of HRV infections and the increasing number of immunocompromised patients underline the need for rapid and accurate diagnosis of HRV infections. In this study, we developed the first quantitative real-time nucleic acid sequence-based amplification assay with an internal control using molecular beacon probes for selective and sensitive detection of human rhinovirus serotypes. We described a simple method to accurately quantify RNA target by computing the time to positivity (TTP) values for HRV RNA. Quantification capacity was assessed by plotting these TTP values against the starting number of target molecules. By using this simple method, we have significantly increased the diagnostic accuracy, precision, and trueness of real-time NASBA assay. Specificity of the method was verified in both in silico and experimental studies. Moreover, for assessment of clinical reactivity of the assay, NASBA has been validated on bronchoalveolar lavage (BAL) specimens. Our quantitative NASBA assay was found to be very specific, accurate, and precise with high repeatability and reproducibility.

Minimum Infective Dose of the Major Human Respiratory and Enteric Viruses Transmitted Through Food and the Environment

Viruses are a significant cause of morbidity and mortality around the world. Determining the minimum dose of virus particles that can initiate infection, termed the minimum infective dose (MID), is important for the development of risk assessment models in the fields of food and water treatment and the implementation of appropriate infection control strategies in healthcare settings. Both respiratory and enteric viruses can be shed at high titers from infected individuals even when the infection is asymptomatic. Presence of pre-existing antibodies has been shown to affect the infectious dose and to be protective against reinfection for many, but not all viruses. Most respiratory viruses appear to be as infective in humans as in tissue culture. Doses of <1 TCID50 of influenza virus, rhinovirus, and adenovirus were reported to infect 50% of the tested population. Similarly, low doses of the enteric viruses, norovirus, rotavirus, echovirus, poliovirus, and hepatitis A virus, caused infection in at least some of the volunteers tested. A number of factors may influence viruses' infectivity in experimentally infected human volunteers. These include host and pathogen factors as well as the experimental methodology. As a result, the reported infective doses of human viruses have to be interpreted with caution.

Molecular characterization of a variant rhinovirus from an outbreak associated with uncommonly high mortality

BACKGROUND

Human rhinoviruses (HRVs) are the most frequent cause of acute upper respiratory tract infection, however, they are also known to replicate in the lower respiratory tract and associate with more severe respiratory illnesses. An outbreak of HRV occurred in a long-term facility in Santa Cruz, California with unusually high morbidity and mortality.

OBJECTIVES

To identify viral characteristics associated with this unique outbreak, genetic relationships between these clinical isolates (SCRVs) and prototype strains of rhinovirus were investigated.

STUDY DESIGN

Sequence homology and phylogenetic analyses of the SCRV VP4/VP2 region were performed in conjunction with all HRV prototypes. Due to the importance of the 5'noncoding region (NCR) and the structural genes to viral replication and host immune responses, respectively, we focused on a segment of the HRV genome which includes these regions. Molecular models of SCRV were also assessed.

RESULTS

SCRV showed closest similarity to HRV82 with some divergence from the prototype. Amino acid differences were concentrated within predicted neutralization epitopes within VP2, VP3 and VP1.

CONCLUSION

Sequence analyses and differences in cell culture growth characteristics suggest that this virus is a variant of HRV which has distinctive properties from its respective prototype strain.

Microbiology of acute otitis media in children with tympanostomy tubes: prevalences of bacteria and viruses

Background. Bacteria are found in 50%–90% of cases of acute otitis media (AOM) with or without otorrhea, and viruses are found in 20%–49% of cases. However, for at least 15% of patients with AOM, the microbiological etiology is never determined. Our aim was to specify the full etiology of acute middle ear infection by using modern microbiological methods concomitantly for bacterial and viral detection.

Methods. The subjects were 79 young children having AOM with new onset (<48 h) of otorrhea through a tympanostomy tube. Middle ear fluid samples were suctioned from the middle ear through the tympanostomy tube. Bacteria were sought by culture and polymerase chain reaction; viruses were analyzed by culture, antigen detection, and polymerase chain reaction.

Results. At least 1 respiratory tract pathogen was noted in 76 children (96%). Bacteria were found in 73 cases (92%), and viruses were found in 55 (70%). In 52 patients (66%), both bacteria and viruses were found. Bacteria typical of AOM were detected in 86% of patients. Picornaviruses accounted for 60% of all viral findings.

Conclusions. In the great majority of children, AOM is a coinfection with bacteria and viruses. The patent tympanostomy tube does not change the spectrum of causative agents in AOM. A microbiological etiology can be established in practically all cases.

Detection of rhinoviruses by tissue culture and two independent amplification techniques, nucleic acid sequence-based amplification and reverse transcription-PCR, in children with acute respiratory infections during a winter season

Five hundred seventeen consecutive nasopharyngeal aspirates were collected between October 1998 and May 1999 for episodes of acute respiratory tract infections in children presenting at the University Hospital of Antwerp. Culture and nucleic acid amplification techniques--nucleic acid sequence-based amplification (NASBA) and reverse transcription-PCR (RT-PCR)--were applied to detect rhinoviruses (RVs). Other respiratory viruses were detected by immunofluorescence (IF) analysis of the specimens and IF analysis of shell vial cultures. Among the 517 specimens, 219 viral agents were identified. They were, in decreasing order, rhinoviruses (93 [18.0%]), respiratory syncytial virus (76 [14.7%]), adenoviruses (16 [3.1%]), influenza viruses (15 [2.9%]), enteroviruses (15 [2.9%]), and herpes simplex virus (4 [0.8%]). For the evaluation of rhinovirus detection, culture positivity and/or a positive reaction in the two independent amplification methods was used as an expanded "gold standard." Based on this standard, the sensitivity, specificity, positive predictive value, and negative predictive value of culture were 44.7, 100, 100, and 99.8%, and those of NASBA and RT-PCR were 85.1, 98.3, 83.3, and 98.5% and 82.9, 93.4, 55.7, and 98.2%, respectively. NASBA and RT-PCR produced comparable results and were significantly more sensitive than virus culture. RVs showed the highest incidence in acute respiratory tract infections in children.

Improved detection of rhinoviruses by nucleic acid sequence-based amplification after nucleotide sequence determination of the 5' noncoding regions of additional rhinovirus strains

The isothermal nucleic acid sequence-based amplification (NASBA) system was applied for the detection of rhinoviruses using primers targeted at the 5' noncoding region (5' NCR) of the viral genome. The nucleotide sequence of the 5' NCRs of 34 rhinovirus isolates was determined to map the most conserved regions and design more appropriate primers and probes. The assay amplified RNA extracted from 30 rhinovirus reference strains and 88 rhinovirus isolates, it did not amplify RNA from 49 enterovirus isolates and other respiratory viruses. The assay allows one to discriminate between group A and B rhinoviruses. Sensitivities for the detection of group B and group A rhinoviruses was 20 and 200 50% tissue culture infective doses, respectively.

Importance of respiratory viruses in acute otitis media

Acute otitis media is usually considered a simple bacterial infection that is treated with antibiotics. However, ample evidence derived from studies ranging from animal experiments to extensive clinical trials supports a crucial role for respiratory viruses in the etiology and pathogenesis of acute otitis media. Viral infection of the upper respiratory mucosa initiates the whole cascade of events that finally leads to the development of acute otitis media as a complication. The pathogenesis of acute otitis media involves a complex interplay between viruses, bacteria, and the host's inflammatory response. In a substantial number of children, viruses can be found in the middle-ear fluid either alone or together with bacteria, and recent studies indicate that at least some viruses actively invade the middle ear. Viruses appear to enhance the inflammatory process in the middle ear, and they may significantly impair the resolution of otitis media. Prevention of the predisposing viral infection by vaccination against the major viruses would probably be the most effective way to prevent acute otitis media. Alternatively, early treatment of the viral infection with specific antiviral agents would also be effective in reducing the occurrence of acute otitis media.

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 virus-specific interventions is sparse. In this article, the epidemiology, pathogenesis, diagnosis, and management of viral otitis media are reviewed.

Daily home tympanometry to study the pathogenesis of otitis media

A study was conducted to define the temporal relationship between a parent-identified cold episode and the diagnosis of otitis media. Forty children were studied in their homes with the use of daily tympanometry, symptom diaries and weekly otoscopy. A total of 136 patients identified colds, and 43 episodes of otitis media were recorded. New episodes of otitis media were observed in 22% of all colds, and 63% of all otitis media episodes occurred during a cold.

Phylogenetic analysis of rhinovirus isolates collected during successive epidemic seasons

Human rhinoviruses (HRV) have been shown to be the major causative agent for mild respiratory infections, but also associated with more serious diseases, such as acute otitis media and pneumonia in children, and asthma. Despite the economical and medical importance of HRV, little is known about the circulation and genetic diversity of HRV during a given season. The aim of this study was to genetically characterize HRV strains causing acute respiratory infections in a cohort of small children during a 2 years follow-up time. Genetic relationships between 61 HRV field isolates were studied using partial genomic sequencing in the VP4/VP2 region (420 nt) and phylogenetic analysis of these sequences. Sequences from the clinical isolates clustered in the two previously known phylogenetic clades, the designated genetic group 2 (including HRV 14) being more predominant. The maximum genetic variation within group 1 was 32.3% and within group 2 it was 32.7%. Several distinct clusters could be observed, some of which were strictly seasonal, whereas some other variants were detected during several seasons. The results of this study show striking genetic diversity of the HRV strains circulating in a given community during a short time.

Genetic clustering of all 102 human rhinovirus prototype strains: serotype 87 is close to human enterovirus 70

Human rhinoviruses (HRV), common agents of respiratory infections, comprise 102 designated serotypes. The genetic relationships of HRV prototype strains and the possibility of using genetic identification of a given HRV field strain were studied. Genomic sequences in the VP4/VP2 region were obtained from all 102 prototype strains. Phylogenetic analysis included 61 recently isolated Finnish field strains. Seventy-six out of the 102 prototype strains clustered in the HRV genetic group A and 25 in group B. Serotype 87 clustered separately and together with human enterovirus 70. The 'percentage' interserotypic differences were generally similar to those between different enterovirus serotypes, but for six pairs of HRV serotypes they were less than 10%. The maximum variation in genetic group A was 41% at the nucleotide level and 28% at the amino acid level, and in genetic group B 34% and 20%, respectively. Judging from the observed interserotypic differences, the 61 Finnish field isolates might represent as many as 19 different serotypes. One cluster of the field strains did not directly associate with any of the prototype strains and might represent a new serotype. However, larger numbers of field isolates of known serotype need to be characterized, possibly also in the VP1 region, to evaluate the feasibility of genetic typing of HRV strains.

Virological and serological analysis of rhinovirus infections during the first two years of life in a cohort of children

The occurrence of rhinovirus infections in a cohort of 329 children during the first 2 years of life was determined by virus detection and serological methods. Rhinovirus detection on nasopharyngeal aspirates and middle ear fluids comprised a combination of virus isolation in HeLa Ohio cells and a reverse transcription-polymerase chain reaction (RT-PCR)-hybridization assay on the inoculated cell cultures. Nasopharyngeal aspirates were collected when the child was referred to the study clinic because of respiratory symptoms. Nasopharyngeal aspirates and middle ear fluids were collected after clinical diagnosis of an acute otitis media. Complement-fixing antibodies to rhinovirus were determined from scheduled serum specimens collected at 6, 12, 18, and 24 months of age and from paired sera taken in the cases of acute otitis media. Rhinovirus infections were shown to be common in infants, 24% of the children had complement-fixing antibodies at the age of 6 months and 22% had had at least one rhinovirus episode indicated by virus detection. At the age of 2 years, 91.3% of the children had rhinovirus-specific antibodies, while 79% of the children had experienced rhinovirus infection as judged by the virus detection tests. However, the complement-fixation assay was poor as a diagnostic test. Of 458 acute otitis media episodes studied, 41% were shown to be associated with a rhinovirus by RT-PCR-hybridization, while significant fourfold rise in rhinoviral antibodies was detected only in 7% of the cases.

Early detection of acute rhinovirus infections by a rapid reverse transcription-PCR assay

The development of a rhinovirus (RV)-RNA-specific reverse transcription (RT)-PCR assay is complicated by the close homology between the RV and enterovirus (EV) genomes in the highly conserved 5'-noncoding region, which is chosen for primer design in most RT-PCR assays. We have developed a sensitive, rapid, and RV-specific nested RT-PCR assay and have used it to test nasopharyngeal aspirates from 556 patients presenting with acute respiratory tract infections. RV RNA was detected by nested RT-PCR not only in all of 52 samples that were RV positive by virus isolation methods but also in 124 of 367 samples that were negative by virus isolation methods and enzyme-linked immunosorbent assay (ELISA). In addition, in 23 of 137 samples that were positive for a different respiratory virus by virus isolation and/or ELISA, RV RNA was detected by RT-PCR. EVs, adenoviruses, respiratory syncytial viruses, coronaviruses, and influenza and parainfluenza viruses, including clinical isolates as well as stock viruses, were not amplified in our RV-specific RT-PCR assay, indicating that this assay was highly specific. The processing time was less than 2 days for the RT-PCR, as opposed to up to 2 weeks for virus isolation. These results indicate that nested RT-PCR is more sensitive than conventional methods for the detection of RV in patients experiencing acute respiratory tract infections and represents the only reliable tool for the early laboratory diagnosis of RV infections. This is especially important in light of new opportunities for therapy currently being developed.

The role of respiratory viruses in otitis media

Evidence derived from numerous studies ranging from animal experiments to extensive clinical trials supports a crucial role for respiratory viruses in acute otitis media. Viral infection of the upper respiratory tract initiates the whole cascade of events that ultimately leads to development of acute otitis media, and viruses contribute to the pathogenesis of this disease by several mechanisms. Recent data indicate that at least some types of viruses actively invade the middle ear and may also interfere with the outcome of otitis media. The availability of effective vaccines against the principal viruses predisposing to acute otitis media could be expected to result in a substantial reduction in the incidence of this disease.

Role of viruses in the pathogenesis of acute otitis media

To date there is ample evidence suggesting a crucial role for respiratory viruses in the pathogenesis of AOM. Respiratory viral infection appears to initiate the cascade of events that finally leads to development of AOM (Fig. 1). The pathogenesis of AOM is complicated, involving a network of factors, some probably not yet identified, which affect each other in a time-dependent manner. Increased knowledge of the detailed mechanisms of viral infection, the host inflammatory response during URI and the interaction between viruses and bacteria could lead to major advances in the prevention of AOM.

Increasing importance of viruses in acute otitis media

Acute otitis media is generally considered a simple bacterial infection that can be effectively treated with antibiotics. However, despite the extensive use of broad-spectrum antibiotics, poor clinical response to treatment of acute otitis media is common in children. Numerous studies ranging from animal experiments to extensive clinical studies have clearly demonstrated that respiratory viruses play a crucial role in the aetiology and pathogenesis of acute otitis media. Viral infection of the upper respiratory tract initiates the whole cascade of events that finally leads to the development of acute otitis media as a complication. Respiratory viruses induce a release of inflammatory mediators in the nasopharynx, increase bacterial colonization and adherence, and have a suppressive effect on the host's immune defense. Recent data indicate that at least some types of viruses actively invade the middle ear. Viruses also seem to enhance the inflammatory process in the middle ear and impair the outcome of the disease. Vaccines against the major viruses predisposing to acute otitis media hold a great promise for the prevention of this disease. Major advances in the management of acute otitis media will require further research into the mechanisms of viral infection, viral-bacterial interaction and the host inflammatory response during viral infection.

Viral-Bacterial Synergy in Otitis Media: Implications for Management

Despite the extensive use of broad-spectrum antibiotics, poor clinical response to the treatment of acute otitis media is common. Evidence derived from numerous studies during the past two decades supports a crucial role for respiratory viruses in the etiology and pathogenesis of acute otitis media, and recent studies indicate that viruses may also have a profound adverse effect on the resolution of this disease. Viruses seem to interact with bacteria and enhance the local inflammatory process in the middle ear. Effective adjuvant therapies are needed to improve outcome in children with otitis media. Increasing knowledge of the role of viruses, viral-bacterial interaction, and host inflammatory mechanisms in otitis media may lead to major improvements in the management of this disease.

Rapid detection of human rhinoviruses in nasopharyngeal aspirates by a microwell reverse transcription-PCR-hybridization assay

A rapid and sensitive microwell reverse transcription (RT)-PCR-hybridization assay was developed to detect human rhinoviruses in clinical specimens and cell culture suspensions. Two hundred three nasopharyngeal aspirates collected from children with symptoms of respiratory disease were analyzed by a classical rolling-tube cell culture method, microwell culture of HeLa Ohio cell monolayers, and RT-PCR with detection of the amplicons in a microwell hybridization assay. The RT-PCR was also done with harvests of the microwell cultures. RNA was extracted with a commercial kit, and the RT-PCR procedure was carried out with microtiter-format equipment. A confirmatory test that exploited a blocking oligonucleotide at the hybridization step was developed to reliably identify marginally positive specimens. Of the 203 nasopharyngeal aspirate specimens, rhinovirus or rhinoviral RNA was detected in 111 specimens (55%). Ninety-eight specimens (48%) were found to be positive by RT-PCR of the original nasopharyngeal aspirates, while the conventional rolling-tube cell culture method yielded 52 (26%) positive specimens. This RT-PCR method with solid-phase hybridization is easy to perform, sensitive, and specific and will be especially useful for analysis of large numbers of clinical specimens.

Prevalence of various respiratory viruses in the middle ear during acute otitis media

BACKGROUND

Vaccines against respiratory viruses may be able to reduce the frequency of acute otitis media. Although the role of respiratory viruses in the pathogenesis of acute otitis media is well established, the relative importance of various viruses is unknown.

METHODS

We determined the prevalence of various respiratory viruses in the middle-ear fluid in 456 children (age, two months to seven years) with acute otitis media. At enrollment and after two to five days of antibiotic therapy, specimens of middle-ear fluid and nasal-wash specimens were obtained for viral and bacterial cultures and the detection of viral antigens. The viral cause of the infections was also assessed by serologic studies of serum samples obtained during the acute illness and convalescence.

RESULTS

A specific viral cause of the respiratory tract infections was identified in 186 of the 456 children (41 percent). Respiratory syncytial virus was the most common virus identified in middle-ear fluid: it was detected in the middle-ear fluid of 48 of the 65 children (74 percent) infected by this virus (P< or =0.04 for the comparison with any other virus). Parainfluenza viruses (15 of 29 children [52 percent]) and influenzaviruses (10 of 24 children [42 percent]) were detected in the middle-ear fluid significantly more often than enteroviruses (3 of 27 children [11 percent]) or adenoviruses (1 of 23 children [4 percent]) (P< or =0.01 for all comparisons).

CONCLUSION

Respiratory syncytial virus is the principal virus invading the middle ear during acute otitis media. An effective vaccine against upper respiratory tract infections caused by respiratory syncytial virus may reduce the incidence of acute otitis media in children.

Analysis of adult otitis media: polymerase chain reaction versus culture for bacteria and viruses

Recent studies using the polymerase chain reaction (PCR) have identified bacterial and viral genomic sequences in culture-negative pediatric middle ear effusions. To evaluate this technique in adults, 19 effusions were analyzed to compare bacterial and viral culture and PCR detection of Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, and adenovirus. Effusions from 4 subjects positive for human immunodeficiency virus (HIV) were analyzed by PCR for HIV virus. Three of 19 effusions were culture-positive for bacteria, and 0 of 19 for viruses. Fifteen of 19 effusions were PCR-positive for bacterial genomic sequences, and 0 of 19 for adenovirus. Thirteen of 15 PCR-positive specimens demonstrated S pneumoniae, 5 of 15 H influenzae, and 0 of 13 M catarrhalis. All 4 effusions from HIV-positive subjects were PCR-positive for HIV. No effusion was culture-positive and PCR-negative. These results confirm that culture-negative middle ear effusions contain genomic sequences from bacterial pathogens. Finding of HIV RNA and DNA in effusion from HIV-positives suggests replicating virus in this fluid.

Role of viruses in middle-ear disease

Taken together, there is ample evidence suggesting a role for viruses in the pathogenesis of OM. This evidence comes from numerous studies performed in animals and in vitro cell cultures, as well as in adults and children with URI and OM. Viruses induce host immune and inflammatory responses that result in pathology of the ET and the middle ear, and predispose the host in various ways to secondary bacterial infection. A suggested mechanism for the pathogenesis of OM following respiratory viral infection is presented in Figure 1.

Comparison of PCR primer pairs in the detection of human rhinoviruses in nasopharyngeal aspirates

The development of a rapid and highly sensitive PCR assay for the detection of human rhinoviruses (HRVs) in nasopharyngeal aspirates is described. Two simple and fast commercial RNA extraction methods and four primer pairs were compared. The most sensitive RNA extraction method (Ultraspec) and primer pair (A) were applied to detection of HRV RNA in 49 nasopharyngeal aspirates, of which 31 had previously been found culture-positive for HRVs. All culture-positive specimens were found positive by PCR. In addition, four of the 18 culture-negative samples were positive by PCR. Primer pair A, however, is not specific for rhinoviruses; it also amplifies enteroviruses, and thus an additional hybridization step with an HRV-specific probe is needed for group-specific diagnosis. The assay was able to detect an amount of HRV-1B RNA corresponding to 0.01 infected cells. In addition, about 50 ag (about 10 genomes) of purified HRV-1B and CBV-3 RNA still gave a signal with this primer pair.

Risk factors for lower respiratory complications of rhinovirus infections in elderly people living in the community: prospective cohort study

OBJECTIVE

To assess the role of rhinoviruses in elderly people living in the community.

DESIGN

Prospective community based surveillance of elderly people, without intervention. Subjects were telephoned weekly to identify symptomatic upper respiratory tract infections. Symptoms and impact of illnesses were monitored, and specimens were collected for diagnostic serology and human rhinovirus polymerase chain reaction.

SETTING

Leicestershire, England.

SUBJECTS

533 subjects aged 60 to 90.

MAIN OUTCOME MEASURES

Symptoms, restriction of activity, medical consultations, and antibiotic use during 96 rhinovirus infections. Adjusted odds ratios for lower respiratory syndromes with respect to smoking and health status.

RESULTS

A viral cause was established in 211 (43%) of 497 respiratory illnesses; rhinoviruses were identified in 121 (24%) and as single pathogens in 107. The median duration of the first or only rhinovirus infection in the 96 people with 107 rhinovirus infections was 16 days; 18 of the 96 patients were confined to bed and 25 were unable to cope with routine household activities. Overall, 60 patients with rhinovirus infections had lower respiratory tract syndromes; 41 patients consulted their doctor, 31 of them (76%) receiving antibiotics. One patient died. Logistic regression analysis showed that chronic medical conditions increased the estimated probability of lower respiratory rhinovirus illness by 40% (95% confidence interval 17% to 68%) and smoking by 47% (14% to 90%). There were almost six times as many symptomatic rhinovirus infections as influenza A and B infections.

CONCLUSIONS

Rhinoviruses are an important cause of debility and lower respiratory illness among elderly people in the community. Chronic ill health and smoking increase the likelihood of lower respiratory complications from such infections. The overall burden of rhinovirus infections in elderly people may approach that of influenza.

Incidence of acute otitis media associated with group A and B respiratory syncytial virus infections

The comparative association of respiratory syncytial virus group A and B infections with acute otitis media was determined by analysing the hospital records of children with community-acquired respiratory syncytial virus infection during three successive outbreaks from 1987 to 1992. Of 326 episodes analysed, 192 (59%) were caused by group A and 134 (41%) by group B infections. Acute otitis media was diagnosed in 101 (75%) children with group B infection, compared with 119 (62%) with group A infection (p = 0.01). Group A infections were more often associated with wheezing (71% versus 59% in group B; p = 0.02) and oxygen therapy in inpatients (48% versus 31%, respectively; p = 0.008). The higher incidence of acute otitis media associated with group B infections was observed both after adjustment for potential confounding variables and during each outbreak.

Detection of enteroviruses and rhinoviruses in clinical specimens by PCR and liquid-phase hybridization

A sensitive method based on PCR followed by liquid-phase hybridization for detection of enterovirus and rhinovirus RNAs in clinical specimens and cell culture supernatants is described. RNA was extracted from stool samples, throat swabs, nasopharyngeal aspirates, cerebrospinal fluid, urine, and plasma with a commercial phenol-guanidinium-chloroform reagent and purified on a polysulfone membrane, on which the reverse transcriptase reaction was also done. Two sets of oligonucleotide primers from the 5' noncoding region of picornaviruses were selected for DNA amplification of 153-bp (enterovirus) and 120-bp (rhinovirus) regions. Double-stranded amplicons were digested into single strands with T7 gene 6 exonuclease and quantitated by an assay using a europium-labeled probe, streptavidin- and biotinylated probe-coated microtitration wells, and time-resolved fluorometry. The sensitivity of the assay was about one template molecule when purified coxsackievirus A9 RNA was used. All enterovirus prototype strains, except echoviruses 22 and 23, and clinical isolates grown in cell culture or suckling mice were strongly positive by the enterovirus PCR-hybridization, as were selected prototype strains and untyped isolates of rhinoviruses by the rhinovirus PCR-hybridization. In a series of 100 clinical specimens tested, the results for 92 agreed with virus culture results. The detection method described will be useful in etiopathogenic studies on enteroviruses and rhinoviruses.

Rapid culture-amplified immunofluorescent test for the detection of human rhinoviruses in clinical samples: evidence of a common epitope in culture

Ohio HeLa cells in multichamber slides were inoculated with nasal samples from patients presenting with common cold symptoms and incubated at 33 degrees C with gentle shaking for 48 hours. The cultures were fixed with cold acetone, and viral antigens were detected by immunofluorescence using an antirhinovirus type 2 (HRV-2) polyclonal serum. Of 158 samples, 58 (36.7%) and 57 (36%) were positive for HRV by virus isolation (confirmed by acid lability test) and by culture-amplified immunofluorescent (CAIF) test, respectively. The correlation between the two tests was highly significant (P = 0.0001). Nasal washings or nasal/throat swabs were equally suitable for detecting virus by isolation but not by CAIF. On the other hand, nasal washings were better than nasal/throat swabs for detecting HRV by CAIF. In an ELISA system, the polyclonal anti-HRV-2 serum recognized a rhinovirus antigen expressed in situ within 48 hr postinfection by all the 11 HRV serotypes investigated. However, 60 hr postinfection, the anti-HRV-2 serum recognized only homologous and closely related HRV antigens. These results suggest that a rhinovirus "common" antigen may be expressed some 48 hr after infection of Ohio HeLa cells with rhinoviruses. The CAIF test provides a sensitive, rapid and reliable procedure to detect wild-type rhinovirus infection as well as a clear alternative to detection by isolation.

Nasal and otologic effects of experimental influenza A virus infection

Past studies showed that experimental rhinovirus colds in adults resulted in eustachian tube dysfunction and abnormal middle ear pressures. In the present study, the symptoms and pathophysiologic findings accompanying experimental influenza viral infection were documented. A total of 33 healthy adult volunteers were intranasally challenged with an influenza A/Kawasaki/86 (H1N1) virus and cloistered over a 9-day postchallenge period to monitor for evidence of infection, signs and symptoms of illness, and the extent and frequency of pathophysiologic responses of the nose, eustachian tube, and middle ear. Results showed a protective effect of high (> or = 16) prechallenge specific hemagglutination-inhibition antibody titer on the rate of infection and the magnitude and extent of provoked symptoms and pathophysiologic findings. Infected subjects with low (< 16) prechallenge serum antibody titers (n = 21) developed significant respiratory illness. These subjects also had objectively measurable increases in nasal secretion production, and decreased nasal patency and mucociliary clearance rates. More than 80% of the infected subjects developed eustachian tube dysfunction, and approximately 80% had middle ear underpressures of less than -100 mm H2O on study days 4 and 5. Five of 21 infected subjects with low prechallenge antibody titers had otoscopic evidence of otitis media with effusion. These results support a causal role for viral upper respiratory tract infection in the pathogenesis of otitis media, possibly mediated by the early development of eustachian tube dysfunction and abnormal middle ear pressure.

Effect of viral respiratory tract infection on outcome of acute otitis media

We prospectively studied 271 infants and children (2 months to 7 years of age) with acute otitis media (AOM) for viral and bacterial causes, outcome at the end of therapy, and frequency of recurrence within 1 month. Comprehensive virologic methods, including viral antigen detection, cell culture, and serologic studies, were used to diagnose viral infection of the respiratory tract, middle ear, or both. Evidence of viral infection was found in 46% (124/271) of patients with AOM. Sixty-six patients (24%) had virus or viral antigen in the middle ear fluid; 50 of these patients (76%) also had bacteria in middle ear fluid, and 16 (24%) had virus alone. More patients with AOM and combined bacterial and viral infection (51%) had persistent otitis (3 to 12 days after institution of antibiotic treatment), compared with those with only bacterial otitis (35%; p = 0.05) or patients with only viral infection (19%; p less than 0.01). Of patients with only viral infection, 4 of 10 with virus in middle ear fluid had persistent otitis, compared with none of 11 patients who had virus only in nasal wash specimens or whose viral infection was diagnosed only by serologic studies. Our data suggest that viruses interact with bacteria and that concurrent viral infection can significantly worsen the clinical course of bacterial AOM. The presence of virus in middle ear fluid may contribute to the pathogenesis and outcome of bacterial AOM. The mechanism of these interactions deserve further investigation.

Pneumonia in childhood: etiology and response to antimicrobial therapy

A prospective eight-month study was carried out in 50 children admitted to hospital for radiologically confirmed community-acquired pneumonia. A potential causative agent of infection was identified in 44 (88%) cases. Using virus isolation, virus antigen detection and enzyme immunoassay serology, respiratory virus infection was diagnosed in 30 (60%) patients. Antibody assays for seven bacteria and antigen detection from serum and urine for Streptococcus pneumoniae produced evidence of bacterial infection in 31 (62%) cases. Streptococcus pneumoniae (38%), respiratory syncytial virus (30%) and Mycoplasma pneumoniae (20%) were the most common causative agents. A mixed infection was diagnosed in 25 (50%) episodes. Nine patients failed to respond to antibiotics within 24 h after onset of treatment. Three of them had a pure viral infection, three a mixed viral-bacterial infection, two a Mycoplasma pneumoniae infection mixed with other bacteria and one a pure Mycoplasma pneumoniae infection. All three Mycoplasma pneumoniae infections were initially treated with penicillin.

Serum antibodies against respiratory tract viruses in episodes of acute otitis media

Although the findings of epidemiological studies have suggested viral respiratory tract infection (RTI) to be crucially involved in the development of acute otitis media (AOM), the relationship between AOM and viral RTI remains unclear. Serum samples, obtained in the acute and convalescent phases of 57 AOM episodes (in 35 children during the first three years of life) were analysed for IgG antibodies against influenza A viruses, influenza B viruses, parainfluenza virus type 1, respiratory syncytial virus and adenoviruses. One third of the AOM episodes (18/57) could be related to viral RTI, as evidenced by significant increases in viral serum antibody activity. Treatment failure occurred in four AOM episodes where increases in serum viral antibody activity were noted. In three of these failures, antibiotic treatment was unsuccessful despite the bacterial strains not being resistant to the drug used. This suggests that concomitant viral infection may be a determinant of treatment outcome in some AOM episodes.

Recurrent wheezy bronchitis and viral respiratory infections

Fifty four patients aged from 1 to 6 years who had had recurrent attacks of wheezy bronchitis were prospectively followed up for three months to find out if there was an association between different viral respiratory infections and episodes of wheezing. Of the 115 episodes of upper or lower respiratory tract symptoms, virus or Mycoplasma pneumoniae infection were diagnosed in 52 (45%). Thirty four of rhinoviruses. The patients had an average of 2.1 episodes of respiratory tract symptoms the total mean (SD) duration of which was 30 (2) days of the 92 days that followed. Wheezing occurred during 76 (66%) of the 115 episodes and during a third of these the patient was admitted to hospital because of severe dyspnoea. Wheezing started a mean (SD) of 43 (7) hours after the first symptoms of respiratory infection and persisted for 3.8 (4.2) days in patients in whom virus infection was diagnosed. The incidence of wheezing was not associated with IgE mediated atopy, with positive virological tests, or with fever during virus infection, but was associated with parental smoking and more than one sibling.

Rhinovirus in otitis media with effusion

We studied rhinovirus in the middle ear fluid of 61 children with subacute or chronic otitis media with effusion. Rhinovirus was recovered from the middle ear fluid of 5 children with subacute otitis media with effusion. The minimum duration of effusion was 32 to 60 days. Additionally, 1 patient had middle ear fluid that was positive for adenovirus. Bacterial pathogens were cultured from the middle ear fluid of 20 of 61 patients. Our finding that rhinovirus can be isolated from middle ear fluid after an asymptomatic period of several weeks suggests its possible role in the development of otitis media with effusion.

Respiratory virus infection as a cause of prolonged symptoms in acute otitis media

We studied respiratory viruses in 22 children with acute otitis media who had failed to improve after at least 48 hours of antimicrobial therapy. The mean duration of preenrollment antimicrobial therapy was 4.8 days. For comparison we studied 66 children with newly diagnosed acute otitis media. Respiratory viruses were isolated from middle ear fluid or from the nasopharynx, or both, significantly more often in the patients unresponsive to initial antimicrobial therapy than in the comparison patients (68% vs 41%, p less than 0.05). Viruses were recovered from the middle ear fluid in 32% of the study patients and from 15% of the comparison group. Bacteria were isolated from the middle ear fluid of four (18%) children in the study group; one child had an isolate resistant to initial antimicrobial therapy. All four children with bacteria in the middle ear fluid had evidence of concomitant respiratory virus infection. Our results indicate that respiratory virus infection is often present in patients with acute otitis media unresponsive to initial antimicrobial therapy, and may explain the prolongation of symptoms of infection. Resistant bacteria seem to be a less common cause of failure of the initial treatment.

Identification of rhinoviruses by cDNA probes

We have used nucleic acid hybridization for the detection and grouping of human rhinoviruses (HRV) according to their genetic relationships. Fifteen rhinovirus reference strains, seventy-one clinical isolates and four enteroviruses were propagated in cell cultures, spotted onto membrane filters and hybridized with radioactively labelled cDNA probes covering different parts of the genomes of HRV-1B, HRV-2, HRV-14, HRV-85 and HRV-89. When the rhinovirus and enterovirus reference strains were tested, the 5' probe of HRV-2 hybridized with thirteen of the fifteen HRV reference strains, with poliovirus type 3 and with ECHO virus 11. The HRV-14 5' probe reacted with eleven HRV reference strains and with all the enteroviruses studied. Sixty-nine of the 71 clinical isolates were recognised by the HRV-2 5' probe, whereas the HRV-14 probe from the same part of the genome hybridized with 54 field isolates. One of the two isolates that remained negative with the HRV-2 5' probe was detected with the HRV-2 probe that derived from the P2 region of the genome, and the other isolate was not detected by any of the probes. Probes from other parts than the 5' end of the genome were generally more specific, and clusters could be formed based on the reactivity of the HRV strains with these probes.