Chuck Vega, MD, on Managing CABP for the Most Common Presentations

In this podcast, Chuck Vega, MD, speaks about how to treat patients with community-acquired bacterial pneumonia (CABP) and how it is managed for the most common presentations, including the typical bacterial pathogens that cause CABP, the most common symptoms, treatment guidelines, and standard workup of CABP. This podcast is part 1 of a 3-part series on managing CABP. 

Additional Resources:

For more information on community-acquired bacterial pneumonia, visit our CABP Resource Center

Chuck Vega, MD, is a clinical professor of family medicine, the assistant dean for Culture and Community Education, and the director of the Program in Medical Education for the Latino Community at the University of California, Irvine in Irvine, California.



Jessica Bard: Hello, everyone, and welcome to another installment of "Podcast360," your go‑to resource for medical news and clinical updates. I'm your moderator, Jessica Bard, with Consultant360 Specialty Network.

Community‑acquired bacterial pneumonia, CABP, is the leading cause of hospitalizations in the United States. Dr Chuck Vega is here to speak with us today about how CABP is generally treated and managed for the most common presentations.

Dr Vega is a Clinical Professor of Family Medicine, the Assistant Dean for Culture and Community Education, and the director of the program in medical education for the Latino community at the University of California Irvine in Irvine, California.

Thank you for joining us today, Dr Vega. What are the typical bacterial pathogens that cause CABP?

Dr Chuck Vega: I think that's a great question. It's always good to start with the microbiology of a given infection. It's worth pulling out and thinking about the scope of CABP a little bit. Community‑acquired pneumonia ‑‑ it's amazingly common ‑‑ so the counts were 4.5 million outpatient and emergency room visits in the United States every year.

It's one of the most common reasons for hospitalization among adults, as well. About 650 adults are hospitalized with community‑acquired pneumonia every year per 100,000 population in the United States. It's something that we've all been familiar with. We're pretty familiar with the cause of organisms, as well.

The biggest one is still Streptococcus pneumoniae, followed by Haemophilus influenzae. Morecsilla catarrhalis is less common, but it's also there in those top pathogens causing CABP. It's worth noting that the microbiology is changing with CABP. Pneumococcus is the most common bacteria, but the overall incidence of pneumococcal pneumonia is actually decreasing.

One of the big reasons for that is vaccination. About 70 percent of US adults 65 and over have received the pneumococcal vaccine and that's great. It would be great if it was 95 percent, but we can see that that vaccine is having a difference.

It's also having a difference at a much younger age. We're now vaccinating infants routinely against pneumococcus. That is protecting their grandparents really, interestingly enough. That is reducing the pool of pneumococcus out there because kids spread it fairly easily and can spread it to more vulnerable older adults.

It's also worth noting that respiratory viruses have been detected in approximately one‑third of cases of community‑acquired pneumonia, as well. Pneumococcal pneumonia is becoming less common. We're increasingly recognizing viruses as an important cause of community‑acquired pneumonia overall.

Jessica: What are the most common symptoms of CABP?

Dr Vega: I imagine a lot of the folks listening to this podcast can rattle them off, too, because they see these folks all the time. Those who present with a cough, particularly a productive cough with sputum. Having fever or chest pain. Having dyspnea.

It's worth noting that no individual symptom or even a constellation of symptoms, is adequate for the diagnosis of pneumonia without chest imaging. In one study, they looked at the positive predictive value of the combination of fever, tachycardia, rales, and hypoxia ‑‑ mild hypoxia, less than 95 percent oxygen saturation.

They took a look at the patients who had respiratory complaints pertaining to primary care. The positive predictive value of that constellation ‑‑ which is certainly all of those things ‑‑ suggests pneumonia to me. The positive predictive value was still less than 60 percent compared with a chest radiograph as a reference standard.

It's not always easy to identify based on symptoms and signs alone. Particularly in very old and very young patients. Anybody who has some kind of potential immunosuppression can be a lot more subtle in terms of the presentation. We think about things more like altered mental status or just generalized fatigue could actually be a symptom of pneumonia.

Jessica: Let's talk about the treatment guidelines. What are the treatment guidelines for patients with community‑acquired bacterial pneumonia?

Dr Vega: The treatment guidelines that I generally feel are most patient‑centered and that make sense in my practice in Santa Ana, California, come from the American Thoracic Society, and were written in 2019.

In terms of the standard workup, chest X‑ray, PA, and lateral is certainly required. In some patients ‑‑ especially those who are immunocompromised, as I mentioned ‑‑ you might need a chest CT to pick up more subtle findings because they're not mounting an inflammatory response to the pneumonia.

For outpatients ‑‑ which is the primary population I deal with ‑‑ that's it. They don't necessarily need any more testing. Unless they are not improving or they have some other outlying type of symptom or sign that really is concerning, they don't need other testing.

Patients with more moderate disease who are admitted to the hospital, they should get a sputum Gram stain, and culture routinely. Even then, that might be the end of the trail. Chest X‑ray, sputum Gram stain, and culture. That could be it if they are otherwise healthy, particularly if they respond fairly quickly to antibiotic therapy.

If the patient's more frail, if they have a number of high‑risk conditions, if they're immunosuppressed, then we have to think about a range of other testing. That's when blood cultures really can be most helpful. As well as doing a urinary antigen for pneumococcus. Considering even a Legionella PCR test would be reasonable.

Then getting a multiplex PCR in season for viruses such as influenza and RSV. Of course, now everybody gets tested for COVID. That's going to go across the board. As an overarching theme to the work of patient's pneumonias is that at this particular moment in time ‑‑ in June 2021, with the pandemic still going on ‑‑ COVID testing is necessary for everybody.

What's not necessary, but I see fairly frequently ‑‑ even among outpatients ‑‑ is the use of procalcitonin. That's generally not considered necessary to decide on whether to initiate antibiotic treatment for suspected CABP.

That was a lot on workup. Then treatment is fairly straightforward. Among healthy adults with pneumonia, amoxicillin, 1 gram, three times a day. Doxycycline, 100 milligrams, twice a day. I've used a lot of macrolides. I think they're good medications. Unfortunately, we see a pneumococcal resistance rising in this country against macrolides.

Therefore, macrolides really should only be used if the overall rate in the community of pneumococcal resistance is less than 25 percent. It's definitely limiting. I find that most patients do better on amoxicillin or doxycycline. Usually, I'll give a seven‑day course.

If they have some concern regarding, again, immunosuppression or some reason they may not improve as quickly on antibiotics, I might do a 10‑day course.

If they have more chronic diseases present, especially lung disease, diabetes ‑‑ which I see all the time ‑‑ that's going to mandate treatment with amoxicillin coagulate or encephalus foreign, then added in with either doxycycline or a macrolide. This may be two antibiotic therapy for those more at‑risk patients for complications.

The other option is to use a respiratory fluoroquinolone in those cases ‑‑ levofloxacin, moxifloxacin. Steroids should not be used routinely in patients with CABP. It's really reserved for those who are inpatients and who are doing very poorly. If they have septic shock, steroids could be considered. For a lot of healthy folks, they could actually reduce the immune response and make the infection worse.

Finally, I don't treat a ton of patients with severe community‑acquired bacterial pneumonia. For those patients, a beta‑lactam, plus a macrolide, is generally recommended over a beta‑lactam plus a fluoroquinolone. They'll get both in‑house, obviously, in the hospital, via IV treatment.

Jessica: Anything else you think that we've missed on that?

Dr Vega: No. These are the basics, but the basics do you right. With any guideline, of course, your clinical judgment with your patient supersedes the guidelines. This is not a dictation that you have to do exactly these things. I think it also helps you practice better stewardship of resources.

We've been so mindful of that over the past year with the COVID pandemic in terms of not ordering unnecessary tests in terms of not ordering unnecessary treatments that could spur more bacterial resistance over time.

Jessica: Thank you again for joining us today, Dr Vega. We really appreciate your time.

Dr Vega: Oh, it's my pleasure.

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