A qualitative assessment of the diagnosis and management of ventilator-associated pneumonia among critical care clinicians exploring opportunities for diagnostic stewardship.

BACKGROUND: Prompt diagnosis and intervention for ventilator-associated pneumonia (VAP) is critical but can lead to overdiagnosis and overtreatment. OBJECTIVES: We investigated healthcare provider (HCP) perceptions and challenges associated with VAP diagnosis, and we sought to identify opportunities for diagnostic stewardship. METHODS: We conducted a qualitative study of 30 HCPs at a tertiary-care hospital. Participants included attending physicians, residents and fellows (trainees), advanced practice providers (APPs), and pharmacists. Interviews were composed of open-ended questions in 4 sections: (1) clinical suspicion and thresholds for respiratory culture ordering, (2) preferences for respiratory sample collection, (3) culture report interpretation, and (4) VAP diagnosis and treatment. Interviews transcripts were analyzed using Nvivo 12 software, and responses were organized into themes. RESULTS: Overall, 10 attending physicians (75%) and 16 trainees (75%) trainees and APPs believed they were overdiagnosing VAP; this response was frequent among HCPs in practice 5-10 years (91%, n = 12). Increased identification of bacteria as a result of frequent respiratory culturing, misinterpretation of culture data, and fear of missing diagnosis were recognized as drivers of overdiagnosis and overtreatment. Although most HCPs rely on clinical and radiographic changes to initiate work-up, the fear of missing a diagnosis leads to sending cultures even in the absence of those changes. CONCLUSIONS: HCPs believe that VAP overdiagnosis and overtreatment are common due to fear of missing diagnosis, overculturing, and difficulty distinguishing colonization from infection. Although we identified opportunities for diagnostic stewardship, interventions influencing the ordering of cultures and starting antimicrobials will need to account for strongly held beliefs and ICU practices.

A Case of Bartonella Quintana Culture-Negative Endocarditis.

BACKGROUND Culture-negative Bartonella quintana endocarditis is challenging to diagnose and is associated with high mortality rates. Diagnostic confirmation of Bartonella quintana infection requires specialized assays, as identifying Bartonella henselae endocarditis by serology can be difficult due to the high rate of serological cross-reactivity. This is a case report of culture-negative Bartonella quintana endocarditis that was diagnosed with epidemiologic data, histology, and nucleic acid amplification testing. CASE REPORT A 28-year-old man with a history of homelessness was admitted to hospital with worsening productive cough, weight loss, and abdominal pain. A transthoracic echocardiogram (TTE) showed pulmonary valve vegetation and several aortic valve vegetations. His hospital course was complicated by cardiogenic shock and septic shock requiring transfer to a tertiary care medical intensive care unit. Although blood cultures remained negative for bacterial infection, serology testing was positive for Bartonella henselae and Bartonella quintana IgM and IgG. Nucleic acid amplification testing for 16S ribosomal RNA (rRNA) using valve tissue was diagnostic for Bartonella quintana. CONCLUSIONS This case of culture-negative Bartonella quintana endocarditis demonstrates the use of diagnostic nucleic acid amplification methods to confirm the diagnosis.

Ventilator-Associated Pneumonia: Diagnostic Test Stewardship and Relevance of Culturing Practices.

PURPOSE OF REVIEW: Ventilator-associated pneumonia (VAP) is one of the most common infections in the ICU. Prompt diagnosis is vital as mortality increases with delayed antibiotic therapy. However, accurate diagnosis is challenging due to non-specific clinical features in a complicated patient cohort. Microbiological culture data remains a crucial aspect in confirming diagnosis. RECENT FINDINGS: Literature data comparing the benefit of invasive respiratory sampling to non-invasive is inconclusive. Differences in culturing practices translate in overidentification of organisms of unclear significance. Positive culture data in a low pre-test probability does not differentiate between true infection and colonization resulting in overtreatment. Furthermore, there are also opportunities for modifying the reporting of respiratory tract cultures that can better guide antimicrobial therapy. Under the umbrella of antimicrobial stewardship, diagnostic stewardship can be incorporated to create a systematic approach that would target culturing practices to match the right pre-test probability. Ideal outcome will be targeting cultures to the right patient population and minimizing unnecessary treatment.