균혈증을 동반한 황색포도알균 폐렴의 미생물 학적, 임상적 특성

Abstract

Background: There have been limited efforts to evaluate the clinical, microbiological characteristics, and outcomes in patients with Staphylococcus aureus (S. aureus) bacteremic pneumonia (SABP), despite its high mortality. Methods: A total of 164 patients with SABP from August 2008 to December 2020 at a tertiary hospital in South Korea were reviewed. Detailed clinical and microbiological data including genotyping for sequence type (ST), Staphylococcus protein A (spa), staphylococcal cassette chromosome mec (SCCmec), and virulence genes were evaluated. I compared the characteristics and outcomes of major ST versus other STs in methicillin- resistant S. aureus (MRSA) and methicillin-susceptible S. aureus (MSSA) bacteremic pneumonia, and analyzed the risk factors for 30-day mortality. Results: I found that ST8 MRSA and ST6 MSSA were significantly more prevalent in SABP, compared to S. aureus bacteremia (SAB) with other primary sources (P<0.001 and P=0.035, respectively). The 30-day mortality was significantly higher in both MRSA (31.6%, P<0.001) and MSSA bacteremic pneumonia (30.3%, P<0.001) compared to SAB with other primary sources. ST5-SCCmec IIb-t2460 was the most predominant clone (25/98, 25.5%) in MRSA bacteremic pneumonia, and ST5 MRSA that frequently harbored virulence genes such as sdrC, sec, sel, and tst, was significant predictor for 30-day mortality in the multivariate analysis (adjusted OR [aOR], 5.479; 95% confidence interval [CI], 1.440– 20.852; P=0.013). ST72-t126 was the most predominant clone (9/66, 13.6%) in MSSA bacteremic pneumonia, while no strain-specific clinical and microbiological characteristics were observed, compared to non-ST72 MSSA. Conclusions: This study demonstrates the microbiological characteristics of SABP which provides a better understanding of clinical characteristics and outcomes of SABP, and active infection control strategy to prevent healthcare-associated SABP should be considered. Keywords: Staphylococcus aureus, bacteremic pneumonia, sequence type, virulence genes, mortality