Table 3.
Summary of main findings from studies assessing the relationship between vancomycin MIC and prognosis in MSSA bacteraemia and left-sided IE
| Study | Design | SAB/IE (n) | Overall mortality | Genetic factors | Main outcomes analysis | |
|---|---|---|---|---|---|---|
|
| ||||||
| Low VAN MIC (<1.5 μg/mL) | High VAN MIC (≥1.5 μg/mL) | |||||
| Kalil, 2014 [11] | Systematic review and metaanalysis | SAB (8291, both MRSA and MSSA) | 25.8% (1430/5551) | 26.8% (734/2740) | NA | RD 1.6% (95% CI −2.3 to 5.6); p 0.43 (for absolute risk of mortality, combining 30-day mortality and in- hospital mortality) |
| Holmes, 2011 [1] | Prospective multicentre cohort study | SAB (532; 266 of which MSSA treated with β-lactams only) | 12.2% (24/193) | 26.8% (18/68) | NA | p 0.011 (for 30-day mortality) |
| Holmes, 2014 [12] | Analysis of a subset of strains from [1] | SAB (252 MSSA isolates) | NA | NA | Associated to HVM: CC8, agr dysfunction, agr genotype II, blaZ, sea, clfA, splA and ACME locus Associated to LVM: CC22, CC88 and CC188 | Associated to HVM: CC8 p <0.001), agr dysfunction (p 0.014), agr genotype II (p 0.043), blaZ (p 0.002), sea (p <0.001), clfA (p <0.001), splA (p <0.001) and ACME locus (p 0.02). Associated to LVM: CC22 (p <0.001), CC88 (p <0.001) and CC188 (p 0.002) |
| Aguado, 2011 [2] | Retrospective, single-centre cohort | Catheter- related SAB (99, all MSSA) | 10.5% (8/76) | 26.1% (6/23) | NA | p 0.13 (for 30-day mortality) OR = 22.9, (95% CI 6.7 to 78.1) for complicated SAB |
| López-Cortés, 2015 [4] | Prospective, single-centre cohort | SAB (135, all MSSA) | 23.6% (25/106) | 10.3% (3/29) | No differences in agr distribution or absence of δ-haemolysin between isolates with HVM and those with LVM. HVM was not more frequent in specific clones | RR = 0.44 (95% CI 0.14 to 1.35) for 14-day mortality |
| Viedma, 2014 [3] | Retrospective, single-centre cohort | SAB (84, all MSSA) | 24.1%, (7/29) | 45.5% (25/55) | HVM: agr II polymorphism: 17.2% ; average levels of RNAIII gene expression: ΔCt 1.5 ± 2.11 LVM: agr II polymorphism: 41.8% ; average levels of RNAIII gene expression: ΔCt 4.05 ± 3.29 |
In-hospital mortality: p 0.057 agr dysfunction: p 0.023. RNAIII expression: p <0.01 |
| Cervera, 2014 [5] | Prospective, single-centre cohort | MSSA IE (93) | 31% (16/53) | 53% (21/40) | NA | In-hospital mortality: p 0.035; Patients with HVM presented significantly more severe embolic events |
| Current study | Prospective, multicentre cohort | MSSA IE (62) | 32% (9/28) | 27% (9/34) | HVM: agrII polymorphism: 19% LVM: agrII polymorphism: 38% |
In-hospital mortality: p 0.780. agrII polymorphism: p 0.157 |
CI, confidence interval; HVM, high vancomycin MIC; IE, infective endocarditis; LVM, low vancomycin MIC; MIC, minimum inhibitory concentration; MRSA, methicillin-resistant Staphylococcus aureus; MSSA, methicillin-susceptible S. aureus; NA, not addressed; OR, odds ratio; RD, relative difference; RR, relative risk; SAB, S. aureus bacteraemia; VAN, vancomycin.