Molecular characterisation and antimicrobial resistance of Streptococcus agalactiae isolates from dairy farms in China
, , , , , , , et | 16 juin 2023
À propos de cet article
Publié en ligne: 16 juin 2023
Pages: 161 - 167
Reçu: 23 déc. 2022
Accepté: 25 avr. 2023
DOI: https://doi.org/10.2478/jvetres-2023-0027
Mots clés
© 2023 Xiaojiao Ma et al., published by Sciendo
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.
Antimicrobial resistance of Streptococcus agalactiae isolates
| Antimicrobial | Phenotypic isolates (n = 21) | MIC (μg/mL) | ||||
|---|---|---|---|---|---|---|
| Susceptible | Intermediate | Resistant | Range | MIC50 | MIC90 | |
| penicillin | 21 (100%) | 0 | 0 | ≤0.13–>64.00 | 0.13 | 0.25 |
| ampicillin | 15 (71.4%) | 0 | 6 (28.6%) | ≤0.13–>64.00 | 0.25 | 1.00 |
| amoxicillin/clavulanic acid | 18 (85.7%) | 1 (4.8%) | 2 (9.5%) | ≤0.25/0.12–>128.00/64.00 | 0.25/0.12 | 0.50/0.25 |
| oxacillin | 19 (90.5%) | 0 | 2 (9.5%) | ≤0.25–>128.00 | 0.50 | 1.00 |
| cephalothin | 19 (90.5%) | 0 | 2 (9.5%) | ≤0.25–>128.00 | 0.25 | 2.00 |
| ceftiofur | 20 (95.2%) | 0 | 1 (4.8%) | ≤0.25~>128.00 | 0.25 | 0.50 |
| erythromycin | 8 (38.1%) | 3 (14.3%) | 10 (47.6%) | ≤0.25–>128.00 | 4.00 | 128.00 |
| clindamycin | 8 (38.1%) | 1 (4.8%) | 12 (52.1%) | ≤0.13–>64.00 | 32.00 | 64.00 |
| gentamicin | 20 (95.2%) | 0 | 1 (4.8%) | ≤0.25–>128.00 | 1.00 | 4.00 |
| doxycycline | 6 (28.6%) | 8 (38.1%) | 7 (33.3%) | ≤0.25–>128.00 | 8.00 | 16.00 |
| florfenicol | 20 (95.2%) | 0 | 1 (4.8%) | ≤0.25–>128.00 | 2.00 | 4.00 |
| tetracycline | 3 (14.3%) | 0 | 18 (85.7%) | ≤0.25–>128.00 | 64.00 | 128.00 |
| kanamycin | 14 (66.7%) | 4 (19.0%) | 3 (14.3%) | ≤0.50–>256.00 | 16.00 | 64.00 |
| ciprofloxacin | 14 (66.7%) | 3 (14.3%) | 4 (19.0%) | ≤0.13–>64.00 | 1.00 | 16.00 |
| sulfisoxazole | 15 (71.4%) | 0 | 6 (28.6%) | ≤2.00–>1024.00 | 4.00 | 1024.00 |
| sulfamethoxazole | 20 (95.2%) | 0 | 1 (4.8%) | ≤0.12/2.40–>64.00/1216.00 | 0.25/4.80 | 0.50/9.50 |
Primer sequence of drug resistance gene of Streptococcus agalactiae
| Resistance gene | Primer sequence (5-3’) | Annealing temperature (°C) | PCR product size (base pairs) | Reference |
|---|---|---|---|---|
| F: GTGGAGTACTACTACATTTACGAG |
55 | 359 | 31 | |
| F: GCGGAACATTGCATTTGAGGG |
51 | 538 | ||
| F: GGATCGATAGTAGCCATGGG |
53 | 516 | ||
| F: CGCTACATTTGCGAGACTCAG |
55 | 569 | ||
| F: TCTAAAAAGCATGTAAAAGAA |
52 | 645 | 27 | |
| F: GAAAAGGTACTCAACCAAATA |
52 | 639 | ||
| F: CGTAGCATTGGAACAGC |
50 | 316 | ||
| F: CCTACCTATTGTTTGTGGAA |
57 | 944 | 4 |
Serotyping and sequence types in 21 Streptococcus agalactiae strains
| ST | Allelic profile | Number of isolates in MLST (%) | Serotypes (Number of isolates) | ||||||
|---|---|---|---|---|---|---|---|---|---|
| 103 | 16 | 1 | 6 | 2 | 9 | 9 | 2 | 11 (52.4%) | Ia ( |
| 312 | 13 | 1 | 1 | 13 | 1 | 9 | 5 | 2 (9.5%) | II ( |
| 67 | 13 | 1 | 1 | 13 | 1 | 1 | 5 | 1 (4.8%) | II ( |
| 309 | 13 | 1 | 1 | 2 | 1 | 9 | 1 | 1 (4.8%) | III ( |
| 1878 | 13 | 1 | 1 | 13 | 1 | 204 | 5 | 6 (28.6%) | II ( |
The correlations between resistance phenotypes and drug resistance genes of Streptococcus agalactiae isolates
| Antimicrobial classes | Resistant gene | Number of strains with genotype | Number of phenotypes of resistance | Consistency rate (%) |
|---|---|---|---|---|
| tetracyclines | 10 | 18 | 55.6% | |
| 7 | 38.9% | |||
| 0 | 0 | |||
| 2 | 11.1% | |||
| macrolides | 0 | 10 | 0 | |
| 8 | 80.0% | |||
| 0 | 0 | |||
| lincosamides | 0 | 12 | 0 |