SEVERE COMMUNITY-ONSET PNEUMONIA: EVOLVING BACTERIAL MICROBIOLOGY

Abstract

SESSION TITLE: Outcomes in Pneumonia and NTMSESSION TYPE: Rapid Fire Original InvPRESENTED ON: 10/17/2022 12:15 pm - 1:15 pmPURPOSE: Current guidelines have eliminated the concept of healthcare-associated pneumonia (HCAP) in favor of classifying patients with community-onset pneumonia (CoP) as either having or lacking risk factors for antibiotic-resistant bacterial pathogens. However, this paradigm is predicated on understanding the microbiology of these infections. Moreover, the implications of this approach for patients with severe CoP necessitating mechanical ventilation (MV), as opposed to those with less severe pneumonia, remain unknown.METHODS: We retrospectively identified all adult patients during 2019 who were admitted with CoP requiring MV. Pneumonia was diagnosed based on clinical criteria (eg, fever, elevated leukocyte count, sputum production) along with radiologic evidence of a new infiltrate. One investigator reviewed all images to ensure this criterion was fulfilled. All patients with suspected pneumonia underwent lower airway sampling with a blind bronchoscopic brush. The type and distribution of bacterial pathogens isolated served as the primary endpoint. The proportion of subjects with potentially antibiotic-resistant infections represented a secondary endpoint. We excluded patients who were chronically ventilated or who were transferred from other facilities.RESULTS: The final cohort included 84 subjects (mean age 63.2+/-15.6 years, 34.5% female). The group was severely ill and the median Acute Physiology and Chronic Health Evaluation Score equaled 22 while 44.0 % presented in shock. Most infections were monomicrobial (96.4%). Approximately 42.5% of pathogens were Gram-positive organisms. The most commonly isolated bacteria included: Methicillin susceptible Staphylococcus aureus (23.0%), Haemophilus influenzae (11.5%), Klebsiella spp (11.5%) and Streptococcus pneumoniae (10.3%). Pseudomonas aeruginosa was recovered in 10.3% of patients while methicillin resistant S. aureus was seen in 9.2% of subjects. Potentially multidrug resistant bacteria were seen in nearly one in four patients.CONCLUSIONS: A varied mix of pathogens lead to severe CoP necessitating MV. Failure to recognize the diversity of pathogens isolated in this scenario may lead to administration of initially inappropriate antibiotic therapy, an important predictor of outcome in severe infection.CLINICAL IMPLICATIONS: Appreciating local patterns of microbiology is crucial for ensuring appropriate antimicrobial prescribing.DISCLOSURES: No relevant relationships by Syed Nazeer MahmoodNo relevant relationships by Cindy McCartneyNo relevant relationships by Namratha Seetharam MedaNo relevant relationships by Andrew Shorr, value=HonorariaRemoved 03/17/2022 by Andrew ShorrNo relevant relationships by Christian Woods SESSION TITLE: Outcomes in Pneumonia and NTM SESSION TYPE: Rapid Fire Original Inv PRESENTED ON: 10/17/2022 12:15 pm - 1:15 pm PURPOSE: Current guidelines have eliminated the concept of healthcare-associated pneumonia (HCAP) in favor of classifying patients with community-onset pneumonia (CoP) as either having or lacking risk factors for antibiotic-resistant bacterial pathogens. However, this paradigm is predicated on understanding the microbiology of these infections. Moreover, the implications of this approach for patients with severe CoP necessitating mechanical ventilation (MV), as opposed to those with less severe pneumonia, remain unknown. METHODS: We retrospectively identified all adult patients during 2019 who were admitted with CoP requiring MV. Pneumonia was diagnosed based on clinical criteria (eg, fever, elevated leukocyte count, sputum production) along with radiologic evidence of a new infiltrate. One investigator reviewed all images to ensure this criterion was fulfilled. All patients with suspected pneumonia underwent lower airway sampling with a blind bronchoscopic brush. The type and distribution of bacterial pathogens isolated served as the primary endpoint. The proportion of subjects with potentially antibiotic-resistant infections represented a secondary endpoint. We excluded patients who were chronically ventilated or who were transferred from other facilities. RESULTS: The final cohort included 84 subjects (mean age 63.2+/-15.6 years, 34.5% female). The group was severely ill and the median Acute Physiology and Chronic Health Evaluation Score equaled 22 while 44.0 % presented in shock. Most infections were monomicrobial (96.4%). Approximately 42.5% of pathogens were Gram-positive organisms. The most commonly isolated bacteria included: Methicillin susceptible Staphylococcus aureus (23.0%), Haemophilus influenzae (11.5%), Klebsiella spp (11.5%) and Streptococcus pneumoniae (10.3%). Pseudomonas aeruginosa was recovered in 10.3% of patients while methicillin resistant S. aureus was seen in 9.2% of subjects. Potentially multidrug resistant bacteria were seen in nearly one in four patients. CONCLUSIONS: A varied mix of pathogens lead to severe CoP necessitating MV. Failure to recognize the diversity of pathogens isolated in this scenario may lead to administration of initially inappropriate antibiotic therapy, an important predictor of outcome in severe infection. CLINICAL IMPLICATIONS: Appreciating local patterns of microbiology is crucial for ensuring appropriate antimicrobial prescribing. DISCLOSURES: No relevant relationships by Syed Nazeer Mahmood No relevant relationships by Cindy McCartney No relevant relationships by Namratha Seetharam Meda No relevant relationships by Andrew Shorr, value=Honoraria Removed 03/17/2022 by Andrew Shorr No relevant relationships by Christian Woods