Association between microbial characteristics and poor outcomes among patients with methicillin-resistant Staphylococcus aureus pneumonia: a retrospective cohort study

Table 3 Patient characteristics, microbial characteristics, or treatments associated with strain type (N = 65)

Characteristics	USA100 N = 36	USA300 N = 29	P-value
Patient characteristics
Gender: Female	16 (44 %)	9 (31 %)	0.269
Age ≥55 years	24 (67 %)	11 (38 %)	0.021
Hospital admission within previous 12 months	21 (58 %)	11 (38 %)	0.102
Hospital-acquired infection	10 (28 %)	12 (41 %)	0.249
Previous MRSA infection or colonization	8 (22 %)	5 (17 %)	0.618
Positive influenza test	1 (3 %)	2 (7 %)	0.582
Post-infection length of stay: median (IQR), in days^a	6 (2–18)	12 (4–24)	0.232
Charlson Comorbidity Index score: median (IQR)	2 (1–3)	2 (0–4)	0.778
30-day mortality^b	11 (31 %)	4 (14 %)	0.111
Antimicrobial prescribed
Linezolid	11 (31 %)	2 (7 %)	0.018
Vancomycin	33 (92 %)	29 (100 %)	0.247
Microbial characteristics
agr dysfunction	8 (22 %)	4 (14 %)	0.384
Toxic shock syndrome toxin-1	1 (3 %)	0 (0 %)	1.000
hVISA	1 (3 %)	0 (0 %)	1.000
Arginine catabolic mobile element	1 (3 %)	23 (79 %)	<0.001
Panton-Valentine leukocidin	0 (0 %)	26 (90 %)	<0.001
SCCmec
Type II	35 (97 %)	4 (14 %)	<0.001
Type IV	0 (0 %)	25 (86 %)	<0.001

IQR interquartile range, SCCmec staphylococcal cassette chromosome mec, agr accessory gene regulator, PFGE pulsed-field gel electrophoresis, hVISA heterogeneous vancomycin-intermediate S. aureus
^aDefined as the day the first respiratory or blood culture that grew MRSA was collected until the day the patient was either discharged from the hospital or died
^bDefined as death occurring within the first 30 days after the day when the first respiratory or blood culture that grew MRSA was obtained

ISSN: 2047-2994