Positive and negative viral associations in patients with acute respiratory tract infections in primary care: the ECOVIR study.

Introduction: Acute respiratory infections (ARIs) are the most common viral infections encountered in primary care settings. The identification of causal viruses is still not available in routine practice. Although new strategies of prevention are being identified, knowledge of the relationships between respiratory viruses remains limited. Materials and methods: ECOVIR was a multicentric prospective study in primary care, which took place during two pre-pandemic seasons (2018-2019 and 2019-2020). Patients presenting to their General practitioner (GP) with ARIs were included, without selecting for age or clinical conditions. Viruses were detected on nasal swab samples using a multiplex Polymerase Chain Reaction test focused on 17 viruses [Respiratory Syncytial Virus-A (RSV-A), RSV-B, Rhinovirus/Enterovirus (HRV), human Metapneumovirus (hMPV), Adenovirus (ADV), Coronaviruses (CoV) HKU1, NL63, 229E, OC43, Influenza virus (H1 and H3 subtypes), Influenza virus B, Para-Influenza viruses (PIVs) 1-4, and Bocavirus (BoV)]. Results: Among the 668 analyzed samples, 66% were positive for at least one virus, of which 7.9% were viral codetections. The viral detection was negatively associated with the age of patients. BoV, ADV, and HRV occurred more significantly in younger patients than the other viruses (p < 0.05). Codetections were significantly associated with RSV, HRV, BoV, hMPV, and ADV and not associated with influenza viruses, CoV, and PIVs. HRV and influenza viruses were negatively associated with all the viruses. Conversely, a positive association was found between ADV and BoV and between PIVs and BoV. Conclusion: Our study provides additional information on the relationships between respiratory viruses, which remains limited in primary care.

The Role of Biomarkers in Influenza and COVID-19 Community-Acquired Pneumonia in Adults.

Pneumonia is a growing problem worldwide and remains an important cause of morbidity, hospitalizations, intensive care unit admission and mortality. Viruses are the causative agents in almost a fourth of cases of community-acquired pneumonia (CAP) in adults, with an important representation of influenza virus and SARS-CoV-2 pneumonia. Moreover, mixed viral and bacterial pneumonia is common and a risk factor for severity of disease. It is critical for clinicians the early identification of the pathogen causing infection to avoid inappropriate antibiotics, as well as to predict clinical outcomes. It has been extensively reported that biomarkers could be useful for these purposes. This review describe current evidence and provide recommendations about the use of biomarkers in influenza and SARS-CoV-2 pneumonia, focusing mainly on procalcitonin (PCT) and C-reactive protein (CRP). Evidence was based on a qualitative analysis of the available scientific literature (meta-analyses, randomized controlled trials, observational studies and clinical guidelines). Both PCT and CRP levels provide valuable information about the prognosis of influenza and SARS-CoV-2 pneumonia. Additionally, PCT levels, considered along with other clinical, radiological and laboratory data, are useful for early diagnosis of mixed viral and bacterial CAP, allowing the proper management of the disease and adequate antibiotics prescription. The authors propose a practical PCT algorithm for clinical decision-making to guide antibiotic initiation in cases of influenza and SARS-CoV-2 pneumonia. Further well-design studies are needed to validate PCT algorithm among these patients and to confirm whether other biomarkers are indeed useful as diagnostic or prognostic tools in viral pneumonia.

Pathophysiology of Influenza D Virus Infection in Specific-Pathogen-Free Lambs with or without Prior Mycoplasma ovipneumoniae Exposure.

Polymicrobial pneumonias occur frequently in cattle, swine, and sheep, resulting in major economic losses. Individual pathogens comprising these complex infections may be mild on their own but can instead exhibit synergism or increase host susceptibility. Two examples of such pathogens, Mycoplasma ovipneumoniae (M. ovipneumoniae) and influenza D viruses (IDVs), naturally infect domestic sheep. In sheep, the role of M. ovipneumoniae in chronic nonprogressive pneumonia is well-established, but the pathogenesis of IDV infection has not previously been studied. We utilized a specific-pathogen-free sheep flock to study the clinical response to IDV infection in naïve vs. M. ovipneumoniae-exposed lambs. Lambs were inoculated intranasally with M. ovipneumoniae or mock infection, followed after four weeks by infection with IDV. Pathogen shedding was tracked, and immunological responses were evaluated by measuring acute phase response and IDV-neutralizing antibody titers. While lamb health statuses remained subclinical, M. ovipneumoniae-exposed lambs had significantly elevated body temperatures during IDV infection compared to M. ovipneumoniae-naïve, IDV-infected lambs. Moreover, we found a positive correlation between prior M. ovipneumoniae burden, early-infection IDV shedding, and IDV-neutralizing antibody response. Our findings suggest that IDV infection may not induce clinical symptoms in domestic sheep, but previous M. ovipneumoniae exposure may promote mild IDV-associated inflammation.

Respiratory viral infections other than SARS CoV-2 among the North Indian patients presenting with acute respiratory illness during the first COVID-19 wave.

Acute respiratory infections due to viral or bacterial etiology can cause 60 deaths per one lakh population. Viral etiology is more common as compared to bacterial, but lack of definite diagnosis leads to increased usage of empirical antibiotics. During the first wave of the COVID-19 pandemic, there was a need to identify co-infections especially in severe acute respiratory illness (SARI) patients to identify it as one of the cofactors for increased severity of illness and to identify the causative agents in COVID-19 negative individuals. The SARS CoV-2 real time PCR was carried out using ICMR approved kits and the other respiratory viruses were detected using the multiplex commercially available real time  kit. A total of 186 patients presenting with either SARI (89.8%) or influenza like illness (10.2%) were included in the study. Out of these, 43 (23.1%) were positive for SARS CoV-2 RNA and 2 (4.6%) patients with SARI showed concomitant infection with either human rhinovirus or human respiratory syncytial virus . Out of 143 patients negative for SARS CoV-2, 35 (24.5%) were positive for one or more microbial infections and 28 (19.6%) infected with other respiratory viral infection most common being human rhinovirus. The results suggest that viral coinfections are significantly higher among COVID-19 negative individuals (24.5% vs 4.6%) presenting with respiratory illness as compared to COVID-19 positive individuals possibly due to viral interference and competitive advantage of SARS-CoV-2 in modulating the host immunity. Further detailed research is required for the understanding of mechanisms of viral co-infection.

Epidemiology and Clinical Impact of Respiratory Coinfections at Diagnosis of Pneumocystis jirovecii Pneumonia.

BACKGROUND: The role of respiratory coinfections at diagnosis of Pneumocystis jirovecii pneumonia (PcP) on clinical impact has been underestimated. METHODS: A retrospective observational study was conducted January 2011 to April 2019 to evaluate respiratory coinfections at diagnosis of PcP patients in 2 tertiary care hospitals. Coinfection was defined by identification of pathogens from P. jirovecii-positive samples. RESULTS: Of 7882 respiratory samples tested for P. jirovecii during the 8-year study, 328 patients with diagnosis of PcP were included. Mean age was 56.7 (SD 14.9) years, 193 (58.8%) were male, 74 (22.6%) had positive HIV serology, 125 (38.1%) had viral coinfection, 76 (23.2%) bacterial coinfection, and 90-day mortality was 25.3%. In the overall population, 90-day mortality was independently associated with solid tumor underlying disease (odds ratio [OR], 11.8; 95% confidence interval [CI], 1.90-78.0; P = .008), sepsis-related organ failure assessment score (SOFA) at admission (OR, 1.62; 95% CI, 1.34-2.05; P< .001), and cytomegalovirus (CMV) respiratory coinfection (OR, 3.44; 95% CI, 1.24-2.90; P = .02). Among HIV-negative patients, respiratory CMV coinfection was associated with worse prognosis, especially when treated with adjunctive corticosteroid therapy. CONCLUSIONS: Respiratory CMV coinfection at PcP diagnosis was independently associated with increased 90-day mortality, specifically in HIV-negative patients.

Bordetella bronchiseptica promotes adherence, colonization, and cytotoxicity of Streptococcus suis in a porcine precision-cut lung slice model.

Bordetella (B.) bronchiseptica and Streptococcus (S.) suis are major pathogens in pigs, which are frequently isolated from co-infections in the respiratory tract and contribute to the porcine respiratory disease complex (PRDC). Despite the high impact of co-infections on respiratory diseases of swine (and other hosts), very little is known about pathogen-pathogen-host interactions and the mechanisms of pathogenesis. In the present study, we established a porcine precision-cut lung slice (PCLS) model to analyze the effects of B. bronchiseptica infection on adherence, colonization, and cytotoxic effects of S. suis. We hypothesized that induction of ciliostasis by a clinical isolate of B. bronchiseptica may promote subsequent infection with a virulent S. suis serotype 2 strain. To investigate this theory, we monitored the ciliary activity by light microscopy, measured the release of lactate dehydrogenase, and calculated the number of PCLS-associated bacteria. To study the role of the pore-forming toxin suilysin (SLY) in S. suis-induced cytotoxicity, we included a SLY-negative isogenic mutant and the complemented mutant strain. Furthermore, we analyzed infected PCLS by histopathology, immunofluorescence microscopy, and field emission scanning electron microscopy. Our results showed that pre-infection with B. bronchiseptica promoted adherence, colonization, and, as a consequence of the increased colonization, the cytotoxic effects of S. suis, probably by reduction of the ciliary activity. Moreover, cytotoxicity induced by S. suis is strictly dependent on the presence of SLY. Though the underlying molecular mechanisms remain to be fully clarified, our results clearly support the hypothesis that B. bronchiseptica paves the way for S. suis infection.

Respiratory Microbial Co-infection With SARS-CoV-2.

Co-infection with additional pathogens is a well-known feature of pandemics. We determined the prevalence and type of a wide variety of respiratory pathogens in 12,075 United States subjects tested for SARS-CoV-2 infection in March and April 2020. Infections with other respiratory pathogens, which on their own produce at least some SARS-CoV-2 symptoms including mortality, were present in both SARS-CoV-2 + and SARS-CoV-2- subjects. Non-SARS-CoV-2 infection rates were significantly higher in SARS-CoV-2 + (86%) patients than SARS-CoV-2- patients (76%) (p < 0.0001). Among the co-pathogens present in both subject groups were K. pneumoniae and M. catarrhalis which can produce serious respiratory illness on their own, Advanced age and nursing home status were associated with higher SARS-CoV-2 + and co-infection rates. Testing for the presence of co-pathogens going forward will assist in the diagnosis and optimal treatment of suspected SARS-CoV-2 respiratory infections in the current pandemic.

Procalcitonin (PCT) levels for ruling-out bacterial coinfection in ICU patients with influenza: A CHAID decision-tree analysis.

OBJECTIVES: To define which variables upon ICU admission could be related to the presence of coinfection using CHAID (Chi-squared Automatic Interaction Detection) analysis. METHODS: A secondary analysis from a prospective, multicentre, observational study (2009-2014) in ICU patients with confirmed A(H1N1)pdm09 infection. We assessed the potential of biomarkers and clinical variables upon admission to the ICU for coinfection diagnosis using CHAID analysis. Performance of cut-off points obtained was determined on the basis of the binominal distributions of the true (+) and true (-) results. RESULTS: Of the 972 patients included, 196 (20.3%) had coinfection. Procalcitonin (PCT; ng/mL 2.4 vs. 0.5, p < 0.001), but not C-reactive protein (CRP; mg/dL 25 vs. 38.5; p = 0.62) was higher in patients with coinfection. In CHAID analyses, PCT was the most important variable for coinfection. PCT <0.29 ng/mL showed high sensitivity (Se = 88.2%), low Sp (33.2%) and high negative predictive value (NPV = 91.9%). The absence of shock improved classification capacity. Thus, for PCT <0.29 ng/mL, the Se was 84%, the Sp 43% and an NPV of 94% with a post-test probability of coinfection of only 6%. CONCLUSION: PCT has a high negative predictive value (94%) and lower PCT levels seems to be a good tool for excluding coinfection, particularly for patients without shock.

[Incidence and severity of pertussis in infants with a respiratory syncytial virus infection]. / Incidencia y gravedad de la tosferina en lactantes coinfectados por el virus respiratorio sincitial.

INTRODUCTION: Pertussis is a re-emerging disease that mostly affects infants. At this age, the severity can be affected by intercurrent infections such as respiratory syncytial virus (RSV). OBJECTIVES: To estimate the incidence of RSV infection during an epidemic period in patients hospitalized due to pertussis. The impact on the severity was also observed during hospitalization. PATIENTS AND METHOD: A descriptive study of cases diagnosed with pertussis admitted to a tertiary hospital over a 3year period, where the presence of co-infection with RSV was analyzed. The estimate of severity was estimated using the incidence of complications and the level of care required. RESULTS: From a total of 73 infants with pertussis, 34 occurred in a bronchiolitis season epidemic. A co-infection due to RSV was detected in 17 patients. The mean age was not significantly different compared to the non co-infected. The mean stay and the need for intensive care was similar in both groups. The need for oxygen therapy care and nutritional support was higher in the coinfected patients. CONCLUSIONS: Coinfection with RSV in infants hospitalized with pertussis occurred in ono in 2 patients during a RSV epidemic season, in infants of similar age. Severity in terms of stay, presence of apnea and admission to intensive care was similar, but more need for respiratory care and nutritional support was found.