Background
Methods
Strains collection and examination
Serotyping
Drug susceptibility test
Detection of point mutations in gyrA, gyrB, parC, and parE
Gene | Sequence (5′–3′) | Product size (bp) | Annealing temperature (°C) |
---|---|---|---|
gyrA
| F: TACACCGGTCAACATTGAGG R: TTAATGATTGCCGCCGTCGG | 648 | 60 |
gyrB
| F: CAAACTGGCGGACTGTCAGG R: TTCCGGCATCTGACGATAGA | 345 | 60 |
parC
| F: GTCTGAACTGGGCCTGAATGC R: AGCAGCTCGGAATATTTCGACAA | 248 | 60 |
parE
| F: ATGCGTGCGGCTAAAAAAGTG R: TCGTCGCTGTCAGGATCGATAC | 289 | 60 |
qnrA
| F: ATTTCTCACGCCAGGATTTG R: GATCGGCAAAGGTTAGGTCA | 515 | 50 |
qnrB
| F: GATCGTGAAAGCCAGAAAGG R: ACGATGCCTGGTAGTTGTCC | 468 | 54 |
qnrC
| F: GGGTTGTACATTTATTGAATC R: TCCACTTTACGAGGTTCT | 446 | 50 |
qnrD
| F: CGAGATCAATTTACGGGGAATA R: AACAAGCTGAAGCGCCTG | 581 | 50 |
qnrS
| F: ACGACATTCGTCAACTGCAA R: TAAATTGGCACCCTGTAGGC | 416 | 55 |
aac(6′)-Ib-cr
| F: GCAACGCAAAAACAAAGTTAGG R: GTGTTTGAACCATGTACA | 560 | 55 |
qepA
| F: GCAGGTCCAGCAGCGGGTAG R: CTTCCTGCCCGAGTATCGTG | 217 | 60 |
Detection of PMQR
Statistical analysis
Results
Bacterial isolation
Fluoroquinolone susceptibility testing
Mutations in DNA gyrase and topoisomerase IV genes
Mutations in gyrA gene
Mutations | 2012 (n = 120) | 2013 (n = 114) | 2014 (n = 85) | 2015 (n = 81) | Total (n = 400) |
---|---|---|---|---|---|
Ser83Leu | 79.2 (95) | 75.4 (86) | 75.3 (64) | 70.4 (57) | 75.5 (302) |
Asp87Asn/ Gly | 65.0 (78) | 50.9 (58) | 61.2 (52) | 50.6 (41) | 57.3 (229) |
Asp87Asn | 24.2 (29) | 24.6 (28) | 41.2 (35) | 37.0 (30) | 30.5 (122) |
Asp87 Gly | 40.8 (49) | 26.3 (30) | 20.1 (17) | 13.6 (11) | 26.8 (107) |
His211Tyr | 75.0 (90) | 74.6 (85) | 75.3 (64) | 69.1 (56) | 73.8 (295) |
Gln517Arg | 5.8 (7) | 3.5 (4) | 2.5 (2) | 0.0 (0) | 3.3 (13) |
Ser80Ile | 77.5 (93) | 75.4 (86) | 75.3 (64) | 67.9 (55) | 74.5 (298) |
Ser129Pro | 33.3 (40) | 41.2 (47) | 52.9 (45) | 24.7 (20) | 38.0 (152) |
Mutations in parC gene
Mutation in gyrB and parE genes
Mutations and fluoroquinolone susceptibility
Point mutations | NAL-S & NOR-S strainsa (n = 93) | NAL-R strainsb (n = 303) | NAL-R & NOR-S strains (n = 84) | NOR-R strains (n = 148) |
---|---|---|---|---|
No mutation | 46 (49.5) | 10 (3.3) | 5 (6.0) | 5 (3.4) |
GyrA-Ser83Leu | 14 (15.1) | 286 (94.4) | 77 (91.7) | 138 (93.2) |
GyrA-Asp87Asn/Gly | 11 (11.8) | 217 (71.6) | 28 (33.3) | 122 (82.4) |
GyrA-His211Tyr | 13 (13.9) | 280 (92.4) | 74 (88.1) | 135 (91.2) |
GyrB-Gln517Arg | 3 (3.2) | 10 (3.3) | 3 (3.6) | 3 (2.0) |
ParC-Ser80Ile | 15 (16.1) | 281 (92.7) | 75 (89.3) | 135 (91.2) |
ParC-Ser129Pro | 35 (37.6) | 116 (38.3) | 37 (44.0) | 48 (32.4) |
GyrA-Ser83Leu & ParC-Ser80Ile | 13 (13.9) | 280 (92.4) | 75 (89.3) | 134 (90.5) |
GyrA-Ser83Leu & ParC-Ser80Ile & GyrA-Asp87Asn/Gly | 11 (11.8) | 216 (71.3) | 28 (33.3) | 121 (81.8) |
Mutations and serotypes
Serotypes | Mutation | Years | Total | |||
---|---|---|---|---|---|---|
2012 (%a) | 2013 (%b) | 2014 (%c) | 2015 (%d) | |||
2a (n = 156) |
gyrA-Asp87Asn | 59.6 (28/47) | 53.7 (22/41) | 63.6 (21/33) | 82.9 (29/35) | 64.1 (100/156) |
gyrA-Asp87Gly | 23.4 (11/47) | 9.8 (4/41) | 15.2 (5/33) | 14.3 (5/35) | 16.0 (25/156) | |
1a (n = 75) |
gyrA-Asp87Asn | 0.0 (0/25) | 10.7 (3/28) | 53.8 (7/13) | 0.0 (0/9) | 13.3 (10/75) |
gyrA-Asp87Gly | 88.0 (22/25) | 39.3 (11/28) | 23.1 (3/13) | 33.3 (3/9) | 52.0 (39/75) | |
2b (n = 66) |
gyrA-Asp87Asn | 0.0 (0/21) | 10.5 (2/19) | 8.3 (1/12) | 7.1 (1/14) | 6.1 (4/66) |
gyrA-Asp87Gly | 76.2 (16/21) | 68.4 (13/19) | 58.3 (7/12) | 21.4 (3/14) | 59.1 (39/66) | |
1b (n = 61) |
gyrA-Asp87Asn | 0.0 (0/20) | 0.0 (0/10) | 0.0 (0/12) | 0.0 (0/19) | 0.0 (0/61) |
gyrA-Asp87Gly | 0.0 (0/20) | 0.0 (0/10) | 0.0 (0/12) | 0.0 (0/19) | 0.0 (0/61) |
Characterization of PMQR genes
Isolate number | Serotype | Year of isolation | City | Antibiotic susceptibility | Target gene mutations | PMQR determinants | ||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
NAL | NOR |
gyrA
|
gyrB
|
parC
| ||||||||
F12002 | 3b | 2012 | Nantong | R | R |
qnrB
| ||||||
F12019 | 2b | 2012 | Yangzhou | R | I | Ser83Leu | Asp87Gly | His211Tyr | Ser80Ile |
aac(6′)-Ib-cr
| ||
F12037 | 2a | 2012 | Zhenjiang | S | I | Ser83Leu | His211Tyr | Ser80Ile |
aac(6′)-Ib-cr
| |||
F12066 | 4c | 2012 | Xuzhou | R | R | Ser83Leu | His211Tyr | Ser80Ile |
aac(6′)-Ib-cr
| |||
F12099 | 2b | 2012 | Yangzhou | R | I | Ser83Leu | Asp87Gly | His211Tyr | Ser80Ile | Ser129Pro |
aac(6′)-Ib-cr
| |
F12149 | 4c | 2012 | Xuzhou | R | S | Ser83Leu | His211Tyr | Ser80Ile | Ser129Pro |
aac(6′)-Ib-cr
| ||
F12150 | 2a | 2012 | Xuzhou | R | I | Ser83Leu | His211Tyr | Ser80Ile | Ser129Pro |
aac(6′)-Ib-cr
| ||
F13055 | 4c | 2013 | Changzhou | R | R | Ser83Leu | His211Tyr | Ser80Ile | Ser129Pro |
qnrS
| ||
F13140 | 1a | 2013 | Yangzhou | S | S | Ser83Leu | His211Tyr | Gln517Arg | Ser80Ile |
aac(6′)-Ib-cr
| ||
F14054 | 2b | 2014 | Suqian | R | I | Ser83Leu | Asp87Asn | His211Tyr | Ser80Ile |
aac(6′)-Ib-cr, qnrS
| ||
F15099 | 2a | 2015 | Taizhou | R | R | Ser83Leu | Asp87Asn | His211Tyr | Ser80Ile |
qnrS
| ||
F15100 | 2a | 2015 | Taizhou | R | R | Ser83Leu | Asp87Asn | His211Tyr | Ser80Ile |
qnrS
| ||
F15101 | 2a | 2015 | Taizhou | R | R | Ser83Leu | Asp87Asn | His211Tyr | Ser80Ile |
qnrS
| ||
F15105 | 2a | 2015 | Taizhou | R | R | Ser83Leu | Asp87Asn | His211Tyr | Ser80Ile |
qnrS
| ||
F15106 | 2a | 2015 | Taizhou | R | R | Ser83Leu | Asp87Asn | His211Tyr | Ser80Ile | Ser129Pro |
qnrS
| |
F15107 | 2a | 2015 | Taizhou | R | R | Ser83Leu | Asp87Asn | His211Tyr | Ser80Ile |
qnrS
|