title: Clinical features and risk factors of mortality for bacteremia due to community-onset healthcare-associated methicillin-resistant S. aureus.
abstract: Studies comparing adult community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) and community-onset healthcare-associated MRSA (COHCA MRSA bacteremia have not been available. From 1 January 2010 through 30 October 2010, a prospective observational program was conducted among all patients aged >16 years with positive Staphylococcus aureus blood cultures within 48 h after their arrival at the emergency department of our hospital. Clinical course of infection and infection foci of bacteremia were evaluated. Resistance to oxacillin was confirmed with the presence of mecA gene examined by polymerase chain reaction. Presence of TSST-1, PVL gene, SCCmec elements (I-V), mecA gene, and multilocus sequence typing were identified through methods described elsewhere. Univariate and multivariate analysis revealed that chronic renal failure was significantly more common in COHCA-MRSA than in CA-MRSA. In addition, APACHE III score was significantly higher in COHCA-MRSA than in CA-MRSA. Both the 7-day and 30-day mortality rates in COHCA-MRSA, 14.6% (7/48) and 29.2% (14/48), respectively, were higher than those in CA-MRSA without a significant difference. SCCmec II was more common in COHCA-MRSA, but SCCmecVT was more common in CA-MRSA. The majority of MRSA isolates belonged to ST59, ST239, and ST5. ST59 was significantly more common in CA-MRSA, while ST239 was nearly equally common in both CA-MRSA and COHCA-MRSA. SCCmec III and II isolates were the first and second most resistant to the antibiotics commonly used for S. aureus, whereas SCCmecVT isolates were the most susceptible to these antibiotics. We conclude that, although both CA-MRSA and COHCA-MRSA bacteremia had community onset, these 2 MRSA infections were different in underlying diseases, risk of mortality, SCCmec types, sequence types, and antimicrobial susceptibility. It is more appropriate to understand the MRSA pathogen and clinical features based on etiology and ST types than based on the location of disease onset. CA-MRSA and HCA-MRSA should be differentiated also based on etiology and ST types, in addition to location of acquisition.
authors: Division of Infectious Diseases, Chang Gung Memorial Hospital, Keelung, and Chang Gung University, Kwei-Shan, Tao-Yuan, Taiwan. lee.sch@msa.hinet.net
authors: Sai-Cheong
authors: SC
authors: Lee
authors: Chao-Wei
authors: CW
authors: Lee
authors: Hsiang-Ju
authors: HJ
authors: Shih
authors: Meng-Jiun
authors: MJ
authors: Chiou
authors: Lai-Chu
authors: LC
authors: See
authors: L K
authors: LK
authors: Siu
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D016470:Bacteremia / Q000382:microbiology* / Q000401:mortality*; D001426:Bacterial Proteins / Q000235:genetics; D001427:Bacterial Toxins / Q000235:genetics; D015373:Bacterial Typing Techniques; D017714:Community-Acquired Infections / Q000382:microbiology / Q000401:mortality*; D024901:Drug Resistance, Multiple, Bacterial; D004768:Enterotoxins / Q000235:genetics; D005260:Female; D006801:Humans; D008297:Male; D055624:Methicillin-Resistant Staphylococcus aureus / Q000145:classification / Q000187:drug effects / Q000302:isolation & purification*; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D015999:Multivariate Analysis; D010068:Oxacillin / Q000627:therapeutic use; D046915:Penicillin-Binding Proteins; D011446:Prospective Studies; D012307:Risk Factors; D018089:Superantigens / Q000235:genetics
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004768:Enterotoxins; D046915:Penicillin-Binding Proteins; D018089:Superantigens; C030107:enterotoxin F, Staphylococcal; C487789:mecA protein, Staphylococcus aureus; D010068:Oxacillin