Dr Pin-Kuei Fu., M.D., Ph.D., Associate Professor
Director of respiratory care unit, Department of Critical Care Medicine
Taichung Veterans General Hospital

Dr Pin-Kuei Fu, an attending physician at the Taichung Veterans General Hospital, provides insights into therapeutic strategies for community-acquired pneumonia (CAP) in the context of the ongoing coronavirus disease 2019 (COVID-19) pandemic.

Q1. Given the similarities between symptoms associated with pneumonia and COVID-19, how do you differentiate between the two infections in your practice?

The primary challenge associated with differentiating between pneumonia and COVID-19 is that most people with COVID-19 infections present with mild symptoms. Results from chest x-rays, for instance, reveal that patients with COVID-19 present with mild infiltration in their lungs, which are not discernible from CAP. However, some symptoms enable doctors to differentiate between the two conditions. Loss of taste and loss of smell, for instance, are signs that could indicate that the patient is infected with COVID-19.¹

Another key differentiator between CAP and COVID-19 is the manifestation of dyspnoea. Shortness of breath is a key indication that the patient could be suffering from a COVID-19 infection.¹ In our department, we have observed that ~20% of patients with COVID-19 present with dyspnoea. Some of these patients require oxygen support; in severe cases, patients deteriorate into respiratory failure.

Q2. How has the management of patients with pneumonia changed during the current pandemic?

CAP can be classified as being caused by either typical or atypical pathogens.² Typical pathogens involved in CAP include Mycoplasma pneumoniae, Legionella and Chlamydia pneumoniae. The most common pathogen involved in CAP is Streptococcus pneumoniae.³ In Taiwan, about 1% of CAPs involve pulmonary tuberculosis. COVID-19 can be classified as atypical pneumonia.

Due to the ongoing COVID-19 pandemic, doctors are now more conscious of COVID-19 infections in their patients. In Taiwan, patients are assessed for COVID-19 risk based on their contact and travel histories. Patients who are deemed to be at risk of infection are administered a polymerase chain reaction (PCR) or antibody test. Patients who test positive for COVID-19 infection are treated using remdesivir. The standard treatment regimen for this population of patients also includes either a combination of quinolones and beta-lactams, or beta-lactams and macrolides.

Q3. Empirical coverage with antibacterial therapy is prominently featured in the Taiwanese guidelines for the treatment of community-acquired pneumonia in adults. With the possibility of patients presenting with COVID-19-related pneumonia, has the approach to empiric therapy changed in your practice?

The fundamental principle guiding empiric therapy of CAP has not changed due to the pandemic. The current guidelines for empiric treatment cover both typical and atypical CAP.

COVID-19 can be classified as a variant of atypical pneumonia; patients present with non-typical symptoms such as loss of taste, loss of smell, and dyspnoea. These symptoms are similar to those present in patients infected by other viral infections, such as influenza. Hence, the current guidelines for CAP remain relevant and cover both typical and atypical pathogens, the latter of which includes the COVID-19 virus.

Q4. During the SARS-CoV epidemic in 2003, there was an increase in the number of patients in whom methicillin-resistant Staphylococcus aureus (MRSA) was detected.⁴ Given the various commonalities between SARS-CoV and COVID-19, are doctors more worried about pneumonia caused by multi-drug resistant pathogens in Taiwan? Has this affected the way you approach patients at higher risk of infection with these strains of bacteria?

In my experience, I have encountered patients with COVID-19 as well as MRSA. I have also seen patients with concurrent fungal infections, (such as aspergillosis). Five risk factors have been identified for MRSA in patients with CAP: i) hospitalisation ≥2 days in the previous 90 days; ii) use of antibiotics in the previous 90 days; iii) chronic haemodialysis in the previous 30 days; iv) prior MRSA colonisation; v) congestive heart failure, and vi) gastric acid suppression.⁵ These factors should be considered when prescribing antibiotics for empiric coverage.

Patients who have been infected with influenza are also at a higher risk of aspergillosis infections.⁶ During the H1N1 epidemic in Taiwan, patients with H1N1 infections were also found to be co-infected with aspergillosis. Similarly, patients with COVID-19 infections have also been found to be co-infected with aspergillosis. Viral infections are known to damage the bronchiole, leading to increased susceptibility to aspergillus pneumonia. As such, doctors need to be mindful about potential co-infections with MRSA or aspergillosis in patients with COVID-19.

Q5. Since the start of the COVID-19 pandemic, there have been concerns prompted by the widespread use of antibiotics when treating patients. In your clinical practice, have there been similar concerns? If so, what measures have been adopted to curb this problem?

Precision medicine and targeted therapy are important strategies to help mitigate problems associated with the widespread use of antibiotics. The difficulty associated with CAP is that the causative pathogen is unknown during early assessments of the patients. Hence, it is essential to undertake testing to narrow down the potential causative pathogen. When prescribing antibiotics for empiric treatment, doctors rely on local reports detailing common pathogens involved in CAP in patients in the region. In Taiwan, for instance, the most common pathogen implicated in CAP is pneumococcus; diabetes patients are commonly infected with Klebsiella pneumoniae. Hence, empiric therapy is tailored to target these pathogens. Typically, empiric coverage involves the use of broad-spectrum antibiotics to maximise coverage. When the causative pathogen is identified following testing, patients are taken off broad-spectrum antibiotics and switched to narrow-spectrum antibiotics that are known to be effective specifically for the causative pathogen.

References

1. Romano CM et al. Braz J Med Biol Res 2020;53:e10475.
2. Centers for Disease Control and Prevention. Atypical Pneumonia. Available at: https://www.cdc.gov/pneumonia/atypical/index.html. Accessed October 2020.
3. Brown JS. Clin Med (Lond) 2012;12:538–43.
4. Yap FH et al. Clin Infect Dis2004;39:511–6.
5. Wunderink RG. Am J Crit Care Med 2013;188:896–8.
6. Denning DW, Chakrabarti A. Lancet Infect Dis 2017;17:e357–66.