Background
Methods
Clinical isolates
Antimicrobial susceptibility tests
Detection of quinolone resistance determinants (QRDs) and aminoglycoside resistance determinants (ARDs)
Evaluation of concordance among methods
Results
Prevalence of the QRDs and ARDs among CRE
Species (no. of isolates) | QDRs and ADRs expressed | No. of isolates |
---|---|---|
Escherichia coli (18) |
qnrA
| 2 |
qnrA + oqxB
| 1 | |
aac(6′)-Ib-cr + qnrA
| 6 | |
aac(6′)-Ib-cr + qnrB
| 1 | |
aac(6′)-Ib-cr + NPMA
| 2 | |
aac(6′)-Ib-cr + qnrA + RmtB
| 2 | |
aac(6′)-Ib-cr + qnrA + NPMA
| 3 | |
oqxB + qnrA
| 1 | |
Enterobacter cloacae (20) |
aac(6′)-Ib-cr + qnrA + qnrB
| 9 |
aac(6′)-Ib-cr + qnrA + qnrB + qnrS
| 1 | |
aac(6′)-Ib-cr + qnrB + qnrS
| 1 | |
aac(6′)-Ib-cr + qnrA + oqxB + oqxA+ RmtA
| 1 | |
aac(6′)-Ib-cr + qnrA
| 2 | |
aac(6′)-Ib-cr + qnrA + qepA
| 1 | |
aac(6′)-Ib-cr
| 2 | |
qnrA
| 2 | |
aac(6′)-Ib-cr + qnrA + qnrS
| 1 | |
Klebsiella pneumoniae (31) |
qnrA
| 3 |
qnrA + RmtB
| 1 | |
qnrA + RmtA
| 2 | |
qnrA + qnrB + oqxA + oqxB
| 1 | |
qnrA + oqxA+ RmtA
| 1 | |
qnrA + qnrS + oqxB
| 1 | |
qnrA + qnrS + oqxA + oqxB + RmtA
| 1 | |
aac(6′)-Ib-cr + qnrA
| 1 | |
aac(6′)-Ib-cr + qnrA + oqxA
| 1 | |
aac(6′)-Ib-cr + qnrA + oqxB
| 3 | |
aac(6′)-Ib-cr + qnrA + qepA
| 1 | |
aac(6′)-Ib-cr + qnrA + qnrS + oqxB
| 1 | |
aac(6′)-Ib-cr + qnrA + oqxA + oqxB
| 8 | |
aac(6′)-Ib-cr + qnrA + qnrS+ oqxA + oqxB
| 1 | |
aac(6′)-Ib-cr + qnrA + qnrB + oqxB+ RmtA
| 1 | |
aac(6′)-Ib-cr + qnrA + qnrB + qnrS + oqxB + oqxA + RmtA
| 1 | |
aac(6′)-Ib-cr + qnrA + oqxB + oqxA + NPMA
| 1 | |
aac(6′)-Ib-cr + oqxB+ oqxA
| 1 | |
oqxA + oqxB
| 1 | |
Klebsiella oxytoca (4) |
aac(6′)-Ib-cr + qnrA
| 3 |
aac(6′)-Ib-cr + qnrB+ qnrS
| 1 | |
Enterobacter aerogenes (1) |
aac(6′)-Ib-cr + qnrB + qnrS
| 1 |
Resistance rates with reference agar dilution method
Testing methoda
| Testing results (%, [no. of strains]) | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
CIP | LEV | GEN | AMK | |||||||||
S | I | R | S | I | R | S | I | R | S | I | R | |
ADM | 37.3% (28) | 9.3% (7) | 53.3% (40) | 52.0% (39) | 10.7% (8) | 37.3% (28) | 17.3% (13) | 1.3% (1) | 81.3% (61) | 74.7% (56) | 10.7% (8) | 14.7%(11) |
Vitek-2 | 40.0% (30) | 8.0% (6) | 52.0% (39) | 52.0% (39) | 1.3% (1) | 46.7% (35) | 20.0% (15) | 2.7% (2) | 77.3% (58) | 86.7% (65) | 0 | 13.3%(10) |
Phoenix | 33.3% (25) | 8.0% (6) | 53.3% (40) | 42.7% (32) | 8.0% (6) | 48.0% (36) | 18.7% (14) | 4.0% (3) | 77.3% (58) | 84.0% (63) | 1.3% (1) | 14.7% (11) |
Microscan | 29.3% (22) | 8.0% (6) | 62.7% (47) | 45.3% (34) | 6.7% (5) | 48.0% (36) | 22.7% (17) | 4.0% (3) | 73.3% (55) | 80.0% (60) | 5.3% (4) | 14.7% (11) |
Performance on susceptibility of three automatic systems
Antibiotics | System (concns in mg/l) | % agreement in clinical categories | % essential agreement | No. of errors of different types (%) | ||
---|---|---|---|---|---|---|
Very major | Major | Minor | ||||
CIP | WalkAway (0.12, 1, 2) | 76.0 | 81.3 | 2 (0.2) | 4 (0.4) | 4 (0.4) |
BD Phoenix (0.12, 0.25,0.5, 1,2) | 80.0 | 88.0 | 2 (0.2) | 1 (0.1) | 4 (0.4) | |
Vitek-2 (0.25, 0.5,1, 2, 4) | 85.4 | 84.0 | 3 (0.3) | 2 (0.2) | 7 (0.8) | |
LEV | Walkaway (4, 8) | 78.7 | 86.7 | 2 (0.2) | 2 (0.2) | 3 (0.3) |
BD Phoenix (2, 4, 8) | 77.3 | 84.0 | 1 (0.1) | 2 (0.2) | 4 (0.4) | |
Vitek-2 (1, 2,4, 8, 16) | 81.3 | 81.3 | 3 (0.3) | 3 (0.3) | 7 (0.8) | |
GEN | Walkaway (4, 8) | 86.7 | 89.3 | 5 (0.6) | 1 (0.1) | 2 (0.2) |
BD Phoenix (2, 4, 8) | 90.7 | 90.7 | 3 (0.3) | 2 (0.2) | 3 (0.3) | |
Vitek-2 (1, 2,4, 8, 16) | 89.3 | 90.7 | 3 (0.3) | 2 (0.2) | 3 (0.3) | |
AMK | Walkaway (8, 16, 32) | 92.0 | 94.7 | 1 (0.1) | 1 (0.1) | 0 |
BD Phoenix (8, 16, 32) | 90.7 | 89.3 | 1 (0.1) | 1 (0.1) | 1 (0.1) | |
Vitek-2 (8, 16, 32) | 88.0 | 84.0 | 2 (0.2) | 1 (0.1) | 1 (0.1) |