TABLE 1.
Prevalence of hVISA based on method of screening/detection, origin of study, and isolate selection
| Screening testa | Confirmationa | Country or region (reference[s]) | Isolate source | No. of MRSA isolates | No. (%) of hVISA isolates detected |
|---|---|---|---|---|---|
| No screening test | Macromethod Etest | Israel (37, 38) | Blood | 487 | 43 (8.8) |
| Singapore (16) | Blood | 56 | 3 (5.4) | ||
| USA (41) | Blood | 489 | 71 (14.5) | ||
| PAP-AUC | Australia (8, 24) | Blood/any | 170 | 64 (37.6) | |
| World (4) | Blood | 65 | 19 (29.2) | ||
| Japan (42) | Blood | 20 | 2 (10) | ||
| Simplified PAP | USA (14, 45, 56) | Blood | 738 | 3 (0.4) | |
| Europe (50) | Any | 302 | 0 (0) | ||
| Germany (20) | Any | 85 | 7 (8.2) | ||
| Simplified PAP | PAP | Asia (52) | Any | 1,357 | 58 (4.3) |
| Spain (2) | Device related | 19 | 14 (73.7) | ||
| Japan (22, 29) | Any | 7,774 | 35 (0.5) | ||
| Korea (32, 33) | Any | 4,045 | 24 (0.6) | ||
| Germany (6) | Any | 367 | 2 (0.5) | ||
| Variation of simplified PAP | PAP | Greece (30) | Any | 72 | 1 (1.4) |
| Italy (39) | Any | 179 | 2 (1.1) | ||
| Thailand (36, 58) | Any | 1,049 | 15 (1.4) | ||
| France (44) | Any | 171 | 2 (1.2) | ||
| Mexico (12) | Any | 152 | 1 (0.7) | ||
| Belgium (13) | Any | 2,145 | 4 (0.2) | ||
| Macromethod Etest | PAP | USA (35) | Any | 982 | 2 (0.2) |
| PAP-AUC | USA (46, 47) | Blood/any | 3,299 | 140 (4.2) | |
| Ireland (15) | Any | 3,189 | 73 (2.3) | ||
| UK (34) | Blood/nasal | 2,550 | 86 (3.4) | ||
| Canada (1) | Any | 475 | 25 (5.3) | ||
| Screening agar | PAP | Turkey (49) | Any | 256 | 46 (18) |
| Belgium (43) | Nasal/skin | 455 | 3 (0.7) | ||
| Korea (9) | Any | 37,856 | 18 (<0.1) | ||
| PAP-AUC | France (19) | Any | 2,300 | 255 (11.1) | |
| China (55) | Any | 200 | 26 (13) | ||
| USA (31) | Blood | 22 | 3 (13.6) | ||
| Simplified PAP | France (5) | Any | 48 | 13 (27.1) | |
| MIC based | UK (3) | Any | 11,242 | 0 (0) | |
| Hong Kong (61) | Blood | 52 | 3 (5.8) | ||
| MIC based | PAP | USA (18) | Blood | 30 | 0 (0) |
| Total | 82,698 | 1,063 (1.3) |
Screening and/or confirmation testing included the following tests. For a more detailed discussion on the performance of each test, see reference 25. Simplified population analysis profile (PAP): growth of (1 to 30) colonies on brain heart infusion agar supplemented with 4 mg/liter vancomycin at 48 h is considered positive for hVISA. Variations of simplified PAP include using different inoculum sizes (>10 μl), inoculum concentrations (>0.5 McFarland standard), media (Mueller-Hinton agar), antibiotics (teicoplanin), and/or vancomycin concentrations (3 or 6 mg/liter). PAP: hVISA is present when the graph of isolated colonies on brain heart infusion agar or Mueller-Hinton agar plotted against increasing vancomycin concentration at 48 h is similar to that for the reference (Mu3) strain. Analysis can be standardized using the area under the curve (PAP-AUC) with hVISA being confirmed when the ratio of the test strain to the control strain (Mu3) is between 0.9 and 1.3. Macromethod (2 McFarland standard) Etest on brain heart infusion agar is defined as positive for hVISA if the vancomycin and teicoplanin MICs are ≥8 μg/ml or the teicoplanin MIC is ≥12 μg/ml for the isolate. Screening agars: ≥1 colony isolated after 24 to 48 h on either brain heart infusion agar or Mueller-Hinton agar supplemented with vancomycin or teicoplanin is considered positive for hVISA. MIC-based testing includes standard Etest or vancomycin broth microdilution of resistant subpopulations.