Viruses and atypical bacteria in the respiratory tract of immunocompromised and immunocompetent patients with airway infection

Ten-year retrospective data analysis reveals frequent respiratory co-infections in hospitalized patients in Augsburg

Clinical data on the types of respiratory pathogens which are most frequently engaged in respiratory co-infections of children and adults are lacking. We analyzed 10 years of data on a total of over 15,000 tests for 16 viral and bacterial pathogens detected in clinical samples at the University Hospital of Augsburg, Germany. Co-infection frequencies and their seasonal patterns were examined using a proportional distribution model. Co-infections were detected in 7.3% of samples, with a higher incidence in children and males. The incidence of interbacterial and interviral co-infections was higher than expected, whereas bacterial-viral co-infections were less frequent. H. influenzae, S. pneumoniae, rhinovirus, and respiratory syncytial virus (RSV) were most frequently involved. Most co-infections occurred in winter, but distinct summer peaks were also observed, which occurred even in children, albeit less pronounced than in adults. Seasonality of respiratory (co-)infections decreased with age. Our results suggest to adjust existing testing strategies during high-incidence periods.

Herpesviridae and Atypical Bacteria Co-Detections in Lower Respiratory Tract Samples of SARS-CoV-2-Positive Patients Admitted to an Intensive Care Unit

Shortly after the emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), cases of viral, bacterial, and fungal coinfections in hospitalized patients became evident. This retrospective study investigates the prevalence of multiple pathogen co-detections in 1472 lower respiratory tract (LRT) samples from 229 SARS-CoV-2-positive patients treated in the largest intensive care unit (ICU) in Slovenia. In addition to SARS-CoV-2, (rt)RT-PCR tests were used to detect cytomegalovirus (CMV), Epstein-Barr virus (EBV), herpes simplex virus 1 (HSV-1), herpes simplex virus 2 (HSV-2), varicella zoster virus (VZV), and atypical bacteria: Chlamydia pneumoniae, Mycoplasma pneumoniae and Legionella pneumophila/spp. At least one co-detection was observed in 89.1% of patients. EBV, HSV-1, and CMV were the most common, with 74.7%, 58.1%, and 38.0% of positive patients, respectively. The median detection time of EBV, HSV-1, and CMV after initial SARS-CoV-2 confirmation was 11 to 20 days. Bronchoalveolar lavage (BAL) and tracheal aspirate (TA) samples showed equivalent performance for the detection of EBV, CMV, and HSV-1 in patients with both available samples. Our results indicate that SARS-CoV-2 infection could be a risk factor for latent herpesvirus reactivation, especially HSV-1, EBV, and CMV. However, additional studies are needed to elucidate the clinical importance of these findings.

Incidence of Respiratory Syncytial Virus Infection in Older Adults: Limitations of Current Data

INTRODUCTION

Respiratory syncytial virus (RSV) is an important cause of severe respiratory illness in older adults and adults with respiratory or cardiovascular comorbidities. Published estimates of its incidence and prevalence in adult groups vary widely. This article reviews the potential limitations affecting RSV epidemiology studies and suggests points to consider when evaluating or designing them.

METHODS

Studies reporting the incidence or prevalence of RSV infection in adults in high-income Western countries from 2000 onwards were identified via a rapid literature review. Author-reported limitations were recorded, together with presence of other potential limitations. Data were synthesized narratively, with a focus on factors affecting incidence estimates for symptomatic infection in older adults.

RESULTS

A total of 71 studies met the inclusion criteria, most in populations with medically attended acute respiratory illness (ARI). Only a minority used case definitions and sampling periods tailored specifically to RSV; many used influenza-based or other criteria that are likely to result in RSV cases being missed. The great majority relied solely on polymerase chain reaction (PCR) testing of upper respiratory tract samples, which is likely to miss RSV cases compared with dual site sampling and/or addition of serology. Other common limitations were studying a single season, which has potential for bias due to seasonal variability; failure to stratify results by age, which underestimates the burden of severe disease in older adults; limited generalizability beyond a limited study setting; and absence of measures of uncertainty in the reporting of results.

CONCLUSIONS

A significant proportion of studies are likely to underestimate the incidence of RSV infection in older adults, although the effect size is unclear and there is also potential for overestimation. Well-designed studies, together with increased testing for RSV in patients with ARI in clinical practice, are required to accurately capture both the burden of RSV and the potential public health impact of vaccines.

Effect of influenza vaccination in solid organ transplant recipients: A nationwide population-based cohort study

Vaccination can prevent influenza in solid organ transplant (SOT) recipients. Using a modified season-specific approach over nine consecutive influenza seasons, we investigated influenza vaccination coverage and effectiveness in a population-based nationwide cohort study that included all SOT recipients aged ≥18 years who were living in Denmark from December 1, 2007 to April 1, 2016. The primary outcome was the season-specific risk of all-cause pneumonia admission. Secondary outcomes were season-specific influenza-related admission, intensive care unit (ICU) admission, and all-cause mortality. Crude and adjusted hazard ratios (aHRs) with 95% confidence intervals (CIs) were estimated using Cox proportional hazards regression models. In total, 11 381 person-years of follow-up data were collected from 5745 SOT recipients, 48% of whom were vaccinated. Influenza vaccination was associated with a reduced risk of all-cause pneumonia admission (aHR, 0.83; 95% CI, 0.69-0.99; p = .035) and all-cause mortality (aHR, 0.60; 95% CI, 0.47-0.76; p = .001), but not influenza-related admission (aHR, 0.75; 95% CI, 0.46-1.22; p = .24) or ICU admission (aHR, 0.84; 95% CI, 0.67-1.06; p = .14) during the same season. Despite these benefits, uptake of influenza vaccination among SOT recipients was low. Therefore, annual influenza vaccination needs to be prioritized.

Mapping human papillomavirus, Epstein-Barr virus, cytomegalovirus, adenovirus, and p16 in laryngeal cancer

PURPOSE

Apart from tobacco and alcohol, viral infections are proposed as risk factors for laryngeal cancer. The occurrence of oncogenic viruses including human papilloma virus (HPV) and Epstein-Barr virus (EBV), in laryngeal squamous cell carcinoma (LSCC) varies in the world. Carcinogenesis is a multi-step process, and the role of viruses in LSCC progression has not been clarified. We aimed to analyze the presence and co-expression of HPV, EBV, human cytomegalovirus (HCMV) and human adenovirus (HAdV) in LSCC. We also investigated if p16 can act as surrogate marker for HPV in LSCC.

METHODS

Combined PCR/microarrays (PapilloCheck®) were used for detection and genotyping of HPV DNA, real-time PCR for EBV, HCMV and HAdV DNA detection, and EBER in situ hybridization (EBER-ISH) for EBV detection in tissue from 78 LSCC patients. Additionally, we analyzed p16 expression with immunohistochemistry.

RESULTS

Thirty-three percent (26/78) of LSCC tumor samples were EBV positive, 9% (7/78) HCMV positive and 4% (3/78) HAdV positive. Due to DNA fragmentation, 45 samples could not be analyzed with PapilloCheck®; 9% of the remaining (3/33) were high-risk HPV16 positive and also over-expressed p16. A total of 14% (11/78) of the samples over-expressed p16.

CONCLUSION

These findings present a mapping of HPV, EBV, HCMV and HAdV, including the HPV surrogate marker p16, in LSCC in this cohort. Except for EBV, which was detected in a third of the samples, data show viral infection to be uncommon, and that p16 does not appear to be a specific surrogate marker for high-risk HPV infection in LSCC.

Viral Infection and Respiratory Exacerbation in Children: Results from a Local German Pediatric Exacerbation Cohort

Respiratory viruses play an important role in asthma exacerbation, and early exposure can be involved in recurrent bronchitis and the development of asthma. The exact mechanism is not fully clarified, and pathogen-to-host interaction studies are warranted to identify biomarkers of exacerbation in the early phase. Only a limited number of international exacerbation cohorts were studied. Here, we have established a local pediatric exacerbation study in Germany consisting of children with asthma or chronic, recurrent bronchitis and analyzed the viriome within the nasopharyngeal swab specimens derived from the entire cohort (n = 141). Interestingly, 41% of exacerbated children had a positive test result for human rhinovirus (HRV)/human enterovirus (HEV), and 14% were positive for respiratory syncytial virus (RSV). HRV was particularly prevalent in asthmatics (56%), wheezers (50%), and atopic (66%) patients. Lymphocytes were decreased in asthmatics and in HRV-infected subjects, and patients allergic to house dust mites were more susceptible to HRV infection. Our study thus confirms HRV infection as a strong 'biomarker' of exacerbated asthma. Further longitudinal studies will show the clinical progress of those children with a history of an RSV or HRV infection. Vaccination strategies and novel treatment guidelines against HRV are urgently needed to protect those high-risk children from a serious course of disease.

Treatment of the most common respiratory infections in children

Acute respiratory infections are the most common group of infective diseases in the pediatric population. Although the improvement of health care and vaccination program has led to a significant reduction in the incidence of certain respiratory infections, the combination of a high prevalence in vulnerable pediatric categories and uncritical prescription of antibiotics, due to the inability to adequately distinguish between viruses and bacterial etiology, still represents a significant challenge for the public health system. In order to promote rational antibiotic therapy with an overall improvement of both diagnostic and therapeutic principles, acute respiratory diseases have been the subject of consideration in numerous publications and national guidelines. Nonspecific clinical manifestations with pathogen heterogeneity and both anatomical and physiological characteristics of the child's respiratory system during growth and development have created the need for individualized therapy. Since the guidelines emphasize the undoubtful and crucial benefits of symptomatic therapy (e.g. analgesics in acute otitis media, supplemental oxygen in lower respiratory tract infections with hypoxemia), the use of antibiotics and corticosteroids is indicated in selected cases with a severe clinical picture. The choice of antibiotic depends on the clinical condition, presumed causative agent, and local epidemiologic circumstances. Respiratory support (oxygen therapy and/or artificial ventilation) is reserved for inpatient treatment of cases with a particularly severe clinical picture and associated complications.

Complicating Infections Associated with Common Endemic Human Respiratory Coronaviruses

Coronaviruses OC43, 229E, NL63, and HKU1 are endemic human respiratory coronaviruses that typically cause mild to moderate upper respiratory infections, similar to the common cold. They also may cause simple and complicated lower respiratory infections, otitis media, asthma exacerbations, gastroenteritis, and a few systemic complications. These viruses are usually seasonal (with winter dominance) and affect nearly all age groups. The seasonal and annual variation in virus prevalence has implications for understanding the concept of acquired immunity and its persistence or diminution. Coronaviruses generally have outbreak potential in susceptible populations of any age, particularly in patients with comorbidities, who tend to have increased clinical disease. These 4 coronaviruses are often found in the context of what appears to be coinfection with other pathogens, but especially other viruses. If coronaviruses are not specifically tested for, the sole detection of a viral copathogen would suggest the pathogen is the causative agent, when a coronavirus may be culpable, or both. The detection of these viruses in circumstances where respiratory viruses are generally sought in clinical samples is, therefore, justified. These pathogens can be chronically shed from the respiratory tract, which is more likely to occur among immunocompromised and complicated patients. These viruses share the potential for genetic drift. The genome is among the largest of RNA viruses, and the capability of these viruses to further change is likely underestimated. Given the potential disease among humans, it is justified to search for effective antiviral chemotherapy for these viruses and to consider uses in niche situations should effective therapy be defined. Whereas SARS-CoV-2 may follow the epidemiological pattern of SARS-CoV and extinguish slowly over time, there is yet concern that SARS-CoV-2 may establish itself as an endemic human respiratory coronavirus similar to OC43, 2299E, NL63, and HKU1. Until sufficient data are acquired to better understand the potential of SARS-CoV-2, continued work on antiviral therapy and vaccination is imperative.