The document discusses community-acquired pneumonia (CAP), including its pathophysiology as an acute infection of the pulmonary tissue acquired outside of the hospital. It provides details on the diagnosis, presentation, and treatment of CAP, noting that typical bacteria include Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis. Empiric antibiotic treatment options for CAP are outlined depending on a patient's risk factors, comorbidities, and severity of illness.

1. 1
Background: Community-acquired pneumonia (CAP)
Pathophysiology: The bugs behind it all
 Diagnosis: Chest X-ray (CXR)+ Symptoms
o Infiltrates on CXR
o Fever
o Dyspnea
o Cough
o
 Acute infection of pulmonary tissue
acquired OUTSIDE of the hospital.
 USA: 1.5 million unique CAP
hospitalizations each year.
Community Acquired Pneumonia
Anna Sandler
PharmD Candidate, 2023
 Risk factors:
o Older age
o Chronic comorbidities
o Viral respiratory tract infections
o Smoking and alcohol overuse
 Typical bacteria
o Streptococcus pneumoniae
(G+)
o Haemophilus influenzae (G-)
o Moraxella catarrhalis (G-)
o Staphylococcus aureus (G+)
o Klebsiella spp. (G-)
o Escherichia coli (G-)
o Anaerobes
 Atypical bacteria
o Legionella spp.
o Mycoplasma pneumoniae
o Chlamydia pneumoniae
 Respiratory viruses*
*Influenza A and B, SARS-CoV-2, rhinoviruses, adenoviruses
**Age (1 point/year), nursing home residency (+10), comorbidities (liver disease + 20; CV disease +10; renal disease +10; CHF
+10;) positive for fever +15; tachycardia; +15; increased respiratory rate +20, pleural effusion +10, elevated BUN +20
Diagnosis, Presentation, and Disposition
 Disposition:
o Pneumonia Severity Index (PSI) > CURB-65
o Score based on different risk factors**

2. 2
Condition Standard Prior respiratory isolation of MRSA or
PsA
Rcent hospitalization
and IV antibiotics +
locally validated riks
factors for MRSA or or
PsA
Nonsevere
inpatient
β Lactam + macrolide or rFLQ
 Ampicillin/sulbactam
 Cefotaxime
 Ceftriaxoe
 Ceftaroline
 Azithromycin
Add covergae and obtain
cultures/nasal PCR
 MRSA: Vancomycin or
linezolid
 PsA: piperacillin-tazobactam,
cefepime, mereopenem,
imipenem
Obtain cultures and add
coverage ONLY if
results are positive
Severe
inpatient****
β Lactam + macrolide or
β Lactam +rFLQ
Add covergae and obtain
cultures/nasal PCR
Add coverage and
obtain cultures
Condition Regimen Comments
No comorbidities or risk
factors for methicillin
resistant Staphylococcus
aureus (MRSA )or
Pseudomonas aeruginosa
(PsA)
 Amoxicillin 1g TID
 Doxycycline 100 mg BID
 Macrolide
Macrolide only
recommended in areas with
pneumococcal resistance to
macrolides <25%
Comorbidities*** Combination therapy:
 Amoxicillin/clavulanate or
 Cefpodoxime or cefuroxime
+
 Macrolide or doxycycline 100 mg BID
o Azithromycin
o Clarithromycin
Monotherapy
Respiratory fluoroquinolone (rFLQ)
 Levofloxacin 750 mg daily
 Moxifloxacin
 Gemifloxacin
No preference between
amoxicillin/clavulante and
cephalosporin when used in
combination treatment
Treatment: Outpatient-Empiric treatment; No < total of 5 days
Treatment: Inpatient-Obtain cultures and gram stain; No < total of 5 days
*** Chronic heart, lung, liver, or renal disease; diabetes mellitus, malignancy, asplenia
**** Either one major criterion or at least three minor criteria have to be met; minor: RR ≥ 30, breaths/min uremia w/ BUN ≥ 20
mg/dL, leukopenia w/ count < 4000 cells/uL; major criteria: septic shock w/ need for pressors, respiratory failure requiring
mechanical ventilation

3. 3
Brand/generic Class/Coverage CAP dosing Adverse Drug Reactions
(ADRSs)/Pearls
Role in CAP
Amoxicillin/Moxatag Beta lactam (BL)-
Penicillin
G+
1 gm PO TID Renally dose adjusted
ADRs:
N/D
Headache
Agitation, anxiety,
seizures, anaphylaxis
Healthy outpatients with no
comorbidities or low risk of
resistant pathogens
Amoxicillin-
clavulanate/Augmentin
Beta lactam-Beta
lactamase inhibitor
(BLBLi)
G+
500mg/125mg
PO TIB
875 mg/125 mg
PO BID
2000 mg/125mg
PO BID
Renally dose adjusted
ADRs: N/V/D, rash, SJS,
thrombocytopenia,
hemolytic anemia,
agitation, anxiety
Part of combination therapy in
outpatients with comorbidities
Ampicillin-
sulbactam/Unasyin
BLBLi
G+,
Enterobacteriaceae
(EB) anaerobes
1.5-3 IV g every
6 hours
Renally dose adjusted
ADRs: Injection site
reactions
Rash, diarrhea
Part of combination therapy in
non-severe or severe inpatient
Piperacillin-tazobactam
/Zosyn
BLBLi
G+, EB, PsA,
anaerobes
4.5 g IV every 6
hours
Renally dose adjusted
ADRs: Diarrhea,
flushing,
thrombophlebitis,
anaphylaxis
Part of combination therapy in
non-severe or severe inpatient
for added PsA coverage
Ceftriaxone/Rocephin BL-third generation
cephalosporin
G+, EB
1-2 g IV daily Not renally dose
adjusted DO NOT use in
hyperbilirubinemic
neonates
DO NOT coadminister
with calcium-containing
solutions
ADRs: Injection site
reaction, pruritis, skin
rash, flushing, anemia,
thrombocytopenia,
increased LFTs
Part of combination therapy in
non-severe or severe inpatient
Ceftaroline/Teflaro BL-fifth generation
cephalosporin
G+, EB, MRSA
600 mg Q12H Renally dose adjusted
ADRs: pruritis, d/n,
anemia, increased LFTs,
anaphylaxis
Part of combination therapy in
non-severe or severe inpatient
Drug Table

4. 4
Cefuroxime/Ceftin BL-second
generation
cephalosporin
G+, EB
500 mg PO BID Renally dose adjusted
ADRs: Diarrhea,
thrombophlebitis, N/V,
increased LFTs
Part of combination therapy in
outpatients with comorbidities
Cefepime/Maxipime BL-fourth
generation
cephalosporin
G+, EB, PsA,
2g IV Q8H Renally dose adjusted
ADRs: Injection site
reactions, skin rash,
D/N/V
Part of combination therapy in
non-severe or severe inpatient
for added PsA coverage
Meropenem/Merrem BL-carbapenem
G+, EB, PsA,
anaerobes
1 g IV Q8H Renally dose adjusted
DDI with valproic acid
decreased levels+
increased risk of
seizures
ADRs: skin rash,
diarrhea, flatulence,
anemia, injection site
reaction, seizures,
Part of combination therapy in
non-severe or severe inpatient
for added PsA coverage
Doxycycline/Vibramycin Tetracycline
G+, MSSA, MRSA,
EB, Atypicals
100 mg PO BID Not renally dose
adjusted
Counseling: Sitting
upright to minimize
esophageal irritation,
photosensitivity,
separating from divalent
and trivalent cations by
2 hours
Avoid in pregnant
women and children > 8
years old due to binding
of growing teeth and
bones
ADRs: N/V/D
Healthy outpatients with no
comorbidities or low risk of
resistant pathogens or as part
of combination therapy in
outpatients with comorbidities

5. 5
Levofloxacin/Levaquin rFLQ
G+, EB, PsA,
atypicals
750 mg PO or IV
once daily
Renally dose adjusted
BBW: Associated with
serious ADRs such as
tendinitis and tendon
rupture, CNS effects,
Contraindication:
Myasthenia gravis
ADRs: D/N/V,
photosensitivity,
hyperglycemia,
hyperkalemia, risk of
aortic aneurysm and
dissection
Counseling: seeking care
if sudden chest pain
occurs, separating from
cations
 Monotherapy in
outpatients with
comorbidities or risk
factors for resistant
pathogens
 Monotherapy in non-
severe inpatients
 Part of combination
therapy in severe
inpatients
Moxifloxacin/Avelox rFLQ
G+, EB, PsA,
atypicals,
anaerobes
400 mg PO or IV
daily
Not renally dose
adjusted
BBW: Associated with
serious ADRs such as
tendinitis and tendon
rupture, CNS effects,
Cis: Myasthenia gravis
ADRs: D/N/V,
hyperglycemia,
hyperkalemia, risk of
aortic aneurysm and
dissection, QTc
prolongation
Counseling: seeking care
if sudden chest pain
occurs, separating from
cations,
 Monotherapy in
outpatients with
comorbidities or risk
factors for resistant
pathogens
 Monotherapy in non-
severe inpatients
 Part of combination
therapy in severe
inpatients

6. 6
Vancomycin/Vancocin Glycopeptide
antibiotic
G+, MRSA,
15 mg/kg IV
Q12H, adjusted
based on levels
At Advocate
Aurora Health
(AAH)-hospital-
based guidelines
Renally dose adjusted
Monitor target trough
levels
ADRs: Injection site
reactions,
nephrotoxicity,
ototoxicity, Red man
syndrome
Part of combination therapy in
non-severe or severe inpatient
for added MRSA coverage
Linezolid/Zyvox Oxazolidinone
G+, MRSA,
600 mg IV Q12H Not renally dose
adjusted
ADRs:
Thrombocytopenia, rare
peripheral or optical
neuropathy
Part of combination therapy in
non-severe or severe inpatient
for added MRSA coverage
Azithromycin/Zithromax Macrolide
G+, EB, atypical
Outpatient: 500
mg PO on first
day then 250
mg PO daily
Inpatient: 500
mg IV daily
Potent CYP3A4 inhibitor
Not renally excreted
ADRs: dose-related
diarrhea, QTc
prolongation
 Part of combination
therapy in outpatients
with comorbidities or
risk factors
 Potentially as
monotherapy in healthy
outpatients without
comorbidities
 Part of combination
therapy in non-severe
or severe inpatient
Clarithromycin Macrolide
G+, EB, atypical
Outpatient: 500
mg PO BID or
1000 mg PO
daily (ER
product)
Inpatient: 500
mg PO BID
Potent CYP3A4 inhibitor
Not renally excreted
ADRs: dose-related
diarrhea, QTc
prolongation>
azithromycin, metallic
taste
 Part of combination
therapy in outpatients
with comorbidities or
risk factors
 Potentially as
monotherapy in healthy
outpatients without
comorbidities
 Part of combination
therapy in non-severe
or severe inpatient
Color Meaning
Left column color Antibiotic class
Light green, right column Use in both outpatient and inpatient
Salmon pink, right column Use in outpatient
Red, right column Use in inpatient
G+: Gram positive, generally includes streptococcus, methicillin-susceptible Staphylococcus aureus (MSSA) , and enterococci; note, all
cephalosporins lack coverage against enterococci

7. 7
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http://www.ncbi.nlm.nih.gov/books/NBK169248
Picture links:
 https://www.mayoclinic.org/diseases-conditions/pneumonia/symptoms-causes/syc-20354204
 https://www.uptodate.com/contents/image/print?imageKey=ID%2F118722&topicKey=ID%2F11
7561&source=see_link
 https://www.researchgate.net/figure/Pneumonia-Severity-Index-PSI-Score-and-
Interpretation_fig3_5667210
 https://www.mayoclinic.org/diseases-conditions/pneumonia/multimedia/chest-x-ray-showing-
pneumonia/img-20005827
References

8. 8