Prognostic value of pneumococcal urinary antigen test in community-acquired pneumonia

Intrapulmonary Vaccination Induces Long-lasting and Effective Pulmonary Immunity against Staphylococcus aureus Pneumonia

Background

Staphylococcus aureus causes community- and hospital-acquired pneumonia linked to a high mortality rate. The emergence and rapid transmission of multidrug-resistant S. aureus strains has become a serious health concern, highlighting the challenges associated with the development of a vaccine to combat S. aureus pneumonia.

Methods

This study evaluated the effects of intrapulmonary immunization on the immune response and protection against S. aureus lung infection in a respiratory mouse model using a subunit vaccine.

Results

Compared with the intranasal immunized mice, the intrapulmonarily immunized mice had lower levels of pulmonary bacterial colonization and lethality, accompanied by alleviated lung inflammation with reduced proinflammatory cytokines and increased levels of interleukin-10 and antimicrobial peptide following intrapulmonary challenge. Optimal protection was associated with increased pulmonary antibodies and resident memory T cells. Moreover, intrapulmonary immunization provided long-lasting pulmonary protection for at least 6 months, with persistent cellular and humoral immunity in the lungs.

Conclusions

Vaccine reaching the deep lung by intrapulmonary immunization plays a significant role in the induction of efficacious and long-lasting immunity against S. aureus in the lung parenchyma. Hence, intrapulmonary immunization can be a strategy for the development of a vaccine against S. aureus pneumonia.

Immunization through the intrapulmonary route with a subunit of S. aureus vaccine elicited tissue resident memory T cells and antigen-specific antibodies in the lungs, and provided optimal and long-term protection against S. aureus pneumonia.

Bacterial pneumonia coinfection and antimicrobial therapy duration in SARS-CoV-2 (COVID-19) infection

Background

Bacterial respiratory coinfection in the setting of SARS-CoV-2 infection remains poorly described. A description of coinfection and antimicrobial usage is needed to guide ongoing antimicrobial stewardship.

Objectives

To assess the rate of empirical antimicrobial treatment in COVID-19 cases, assess the rate and methods of microbiological sampling, assess the rate of bacterial respiratory coinfections and evaluate the factors associated with antimicrobial therapy in this cohort.

Methods

Inpatients with positive SARS-CoV-2 PCR were recruited. Antibiotic prescription, choice and duration were recorded. Taking of microbiological samples (sputum culture, blood culture, urinary antigens) and culture positivity rate was also recorded. Linear regression was performed to determine factors associated with prolonged antimicrobial administration.

Results

A total of 117 patients were recruited; 84 (72%) were prescribed antimicrobial therapy for lower respiratory tract infections. Respiratory pathogens were identified in seven (6%) patients. The median duration of antimicrobial therapy was 7 days. C-reactive protein level, oxygen requirement and positive cultures were associated with prolonged duration of therapy.

Conclusions

The rate of bacterial coinfection in SARS-CoV-2 is low. Despite this, prolonged courses of antimicrobial therapy were prescribed in our cohort. We recommend active antimicrobial stewardship in COVID-19 cases to ensure appropriate antimicrobial prescribing.

Performance of pneumococcal urinary antigen test in patients with community-onset pneumonia: a propensity score-matching study

BACKGROUND/AIMS

Although pneumococcal urinary antigen tests (PUATs) have universally been used for the diagnosis of pneumococcal pneumonia, data on the efficacy of these exams are limited. The objective of our study was to investigate the clinical impact of the PUAT in patients with community-onset pneumonia (CO-pneumonia).

METHODS

We conducted a retrospective cohort study of patients diagnosed with CO-pneumonia. Patients were classified according to their PUAT results and were matched using the propensity score-matching method. The primary outcome was 30-day mortality.

RESULTS

A total of 1,257 patients were identified and 163 (13.0%) demonstrated positive PUAT results. The sensitivity and specificity values of PUAT for overall pneumococcal pneumonia were 56.5% and 91.4%, respectively. In the full cohort, there were no significant differences in 30-day mortality between the two groups (6.1% in the positive PUAT group vs. 8.2% in the negative PUAT group, p = 0.357). However, in the propensity-matched cohort, the 30-day mortality rates were lower in the positive PUAT group (5.6% vs. 17.4%, p = 0.001). With respect to secondary outcomes, the proportion of patients with potentially drug-resistant pathogens, changes in antibiotics, and failure rates of initial antibiotic therapy were significantly lower in the positive PUAT group than in the negative PUAT group of the propensity-matched cohort.

CONCLUSION

We found that the sensitivity of the index test was low and specificity was high in this clinical setting. And our findings suggest that positive PUAT results may be associated with favorable clinical outcomes in patients with CO-pneumonia.

The change in age distribution of CAP population in Korea with an estimation of clinical implications of increasing age threshold of current CURB65 and CRB65 scoring system

Background

CURB65 and CRB65 score are simple and popular methods to estimate the mortality in patients with community-acquired pneumonia (CAP). Although there has been a global increase in life expectancy and population ageing, we are still using the same age threshold derived from patients in late 1990s to calculate the scores. We sought to assess the implication of using higher age threshold using Korean population data and a single center hospital records.

Methods

Using Korean National Health Insurance Service-National Sample Cohort (NHIS-NSC), we analyzed annual age distribution of CAP patients in Korea from 2005 to 2013 and report how patients aged >65 years increased over time. We also assessed annual change in test characteristics of various age threshold in Korean CAP population. Using a single center hospital registry of CAP patients (2008–2017), we analyzed test characteristics of CURB65 and CRB65 scores with various age thresholds.

Results

116,481 CAP cases were identified from NHIS-NSC dataset. The proportion of patients aged >65 increased by 1.01% (95% CI, 0.70%-1.33%, P<0.001) every year. In the sample Korean population dataset, age threshold showed its peak AUROC (0.829) at 70. In the hospital dataset, 7,197 cases were included for analysis. The AUROC of both CRB65 and CURB65 was maximized at 71. When CRB71 was applied instead of CRB65 for hospital referral using score <1 to define a low-risk case, the potential hospital referral was significantly decreased (72.9% to 64.6%, P<0.001) without any significant increase in 1-month mortality in the low risk group (0.6% to 0.7%, P = 0.690).

Conclusion

There was a significant age shift in CAP population in Korea. Increasing the current age threshold of CURB65 (or CRB65) could be a viable option to reduce ever-increasing hospital referrals and admissions of CAP patients.