Flying under the Radar: Community‐Acquired Methicillin‐Resistant Staphylococcus Aureus Necrotizing Pneumonia in HIV Patients

1University of California, San Francisco, San Francisco, CA
2University of California, San Francisco, San Francisco, CA
3University of California, San Francisco, San Francisco, CA

Meeting: Hospital Medicine 2010, April 8-11, Washington, D.C.

Abstract number: 302

Case Presentation:

A 54‐year‐old man with HIV presented with 2 weeks of flulike illness and 1 day of fever, dyspnea, and pleuritic chest pain. He had a recent CD4 count of 385/mm3, an undetectable viral load, and no history of opportunistic infections, alcohol abuse, or association with health care. On exam he was febrile, tachycardic, tachypneic. and hypoxic to 89% on room air. He appeared moderately ill, and his pulmonary exam revealed diffuse rhonchi and wheezes bilaterally. Labs showed a profound neutrophil‐predominant leukocytosis and an arterial blood gas with mild respiratory acidosis, hypoxia, and an A‐a gradient of 509. Chest x‐ray revealed patchy densities at the right lung base; chest CT confirmed a right lower lobe consolidation with cystic spaces consistent with necrotizing pneumonia. The patient was admitted for community‐acquired pneumonia (CAP) and sepsis, and empirically started on vancomycin, piperacillin/tazobaclam. and azithromycin given the severity of his illness. His blood and sputum cultures grew methicillin‐resistant Staphylococcus aureus (MRSA), sensitive to gentamycin, trimethoprim/sulfamethoxazole, tetracycline, and vancomycin (MIC = 1 μg/mL). He was treated with vancomycin initially, then linezolid when his respiratory status worsened. After a 26‐day hospital stay, he was discharged, completed 8 weeks of linezolid, and required home oxygen.

Discussion:

Hospitalists frequently manage lung diseases in HIV patients and should identify community‐acquired MRSA (CA‐MRSA) as a cause of necrotizing pneumonia in this population. Though CA‐MRSA is recognized as an emerging cause of CAP in the immunocompetent population, often affecting young and previously healthy patients, there are few reports in HIV patients, despite having a 10‐fold increased risk for bacterial pneumonia. Typically, CA‐MRSA pneumonia is preceded by a viral prodrome and is associated with hemoptysis, high fever, leukopenia, hypotension, and chest x‐ray with multilobular infiltrates and/or cavitation. CA‐MRSA pneumonia is frequently fatal, and patients who recover from it often require ventilatory assistance and prolonged hospital stays. The clinical presentation and course are similar in HIV patients, although bacteremia is more common.

Conclusions:

Despite autopsy reports of bacterial pneumonia as the most frequent pulmonary complication in HIV and S. aureus as the second most common bacterial culprit. CA‐MRSA may not be “on the radar“ as a cause of CAP in HIV patients. Given the substantial morbidity and mortality seen with CA‐MRSA pneumonia, and the possibility of increased frequency in HIV patients, providers should consider CA‐MRSA earlier in HIV patients presenting with severe CAP and may choose to initiate broader antibiotic regimens than that recommended by current IDSA/ATS guidelines tc cover MRSA. Vancomycin and linezolid are recommended for CA‐MRSA pneumonia; however, as a monotherapy, linezolid may be preferred because it achieves higher lung concentrations and decreases toxin production.

Author Disclosure:

D. Kuo, none; W. Pendergraft, none; L. Mazotti, none.

To cite this abstract:

Kuo D, Pendergraft W, Mazotti L. Flying under the Radar: Community‐Acquired Methicillin‐Resistant Staphylococcus Aureus Necrotizing Pneumonia in HIV Patients. Abstract published at Hospital Medicine 2010, April 8-11, Washington, D.C. Abstract 302. Journal of Hospital Medicine. 2010; 5 (suppl 1). https://www.shmabstracts.com/abstract/flying-under-the-radar-communityacquired-methicillinresistant-staphylococcus-aureus-necrotizing-pneumonia-in-hiv-patients/. Accessed October 17, 2019.

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