Table 1.
PCR primers used for determination of L. monocytogenes serogroups
| Target gene | Primer name | Primer sequence (5′ → 3′) |
|---|---|---|
| lmo0737 | lmo0737F | AGGGCTTCAAGGACTTACCC |
| lmo0737R | ACGATTTCTGCTTGCCATTC | |
| lmo1118 | lmo1118F | AGGGGTCTTAAATCCTGGAA |
| lmo1118R | CGGCTTGTTCGGCATACTTA | |
| ORF2819 | ORF2819F | AGCAAAATGCCAAAACTCGT |
| ORF2819R | CATCACTAAAGCCTCCCATTG | |
| ORF2110 | ORF2110F | AGTGGACAATTGATTGGTGAA |
| ORF2110R | CATCCATCCCTTACTTTGGAC | |
| Prs | prsR | GCTGAAGAGATTGCGAAAGAAG |
| prsF | CAAAGAAACCTTGGATTTGCGG |
Table 2.
Antimicrobial resistance by sample origin of Listeria monocytogenes isolates from food and food-production environments in Poland
| Antimicrobial agents | Number (%) of isolates* | |||||||
|---|---|---|---|---|---|---|---|---|
| Serogroup IIa (n =146) | Serogroup IVb (n = 137) | |||||||
| Raw meat (n = 31) | Ready-to-eat food (n = 63) | Food-production environment (n = 52) | Total (%) | Raw meat (n = 21) | Ready-to-eat food (n = 108) | Food-production environment (n = 8) | Total (%) | |
| AMP | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| AXO | 17 | 38 | 40 | 95 (65.1)** | 21 | 98 | 7 | 126 (92.0)** |
| CIP | 0 | 1 | 2 | 3 (2.1) | 0 | 1 | 0 | 1 (0.7) |
| CLI | 8 | 17 | 8 | 33 (22.6) | 2 | 25 | 0 | 27 (19.7) |
| ERY | 0 | 0 | 1 | 1 (0.7) | 0 | 0 | 0 | 0 |
| GAT | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| GEN | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| LEVO | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 1 (0.7) |
| LZD | 1 | 1 | 0 | 2 (1.4) | 0 | 5 | 0 | 5 (3.6) |
| OXA | 9 | 25 | 6 | 40 (27.4)** | 11 | 79 | 3 | 93 (67.9)** |
| PEN | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| SYN | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| RIF | 0 | 1 | 0 | 1 (0.7) | 0 | 0 | 0 | 0 |
| STR | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| TET | 0 | 1 | 0 | 1 (0.7) | 0 | 1 | 0 | 1 (0.7) |
| SXT | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| VAN | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
1 AMP – ampicillin; AXO – ceftriaxone; CIP – ciprofloxacin; CLI – clindamycin; ERY – erythromycin; GAT – gatifloxacin; GEN – gentamicin; LEVO – levofloxacin; LZD – linezolid; OXA – oxacillin; PEN – penicillin; SYN – quinupristin/dalfopristin; RIF – rifampicin; STR – streptomycin; TET – tetracycline; SXT – trimethoprim/sulfamethoxazole; VAN – vancomycin
Table 3.
Antimicrobial resistance profiles of Listeria monocytogenes isolates from food and food-production environments in Poland
| Antimicrobial resistance profile | Number (%) of resistant isolates | ||
|---|---|---|---|
| Serogroup IIa (n = 119) | Serogroup IVb (n = 130) | Total (n = 249) | |
| AXO | 59 (49.6)* | 35 (26.9)* | 94 (37.8) |
| OXA | 14 (11.8)* | 3 (2.3)* | 17 (6.8) |
| CLI | 1 (0.8) | 0 | 1 (0.4) |
| AXO-OXA | 9 (7.6)* | 63 (48.5)* | 72 (28.9) |
| AXO-CLI | 14 (11.8)* | 0* | 14 (5.6) |
| CLI-OXA | 8 (6.7)** | 1 (0.8)* | 9 (3.6) |
| AXO-CIP | 1 (0.8) | 1 (0.8) | 2 (0.8) |
| AXO-TET | 0 | 1 (0.8) | 1 (0.4) |
| CLI-LZD | 1 (0.8) | 0 | 1 (0.4) |
| AXO-CLI-OXA | 7 (5.9)* | 20 (15.4)* | 27 (10.8) |
| AXO-CIP-TET | 1 (0.8) | 0 | 1 (0.4) |
| AXO-OXA-RIF | 1 (0.8) | 0 | 1 (0.4) |
| AXO-CIP-OXA | 1 (0.8) | 0 | 1 (0.4) |
| AXO-CLI-ERY | 1 (0.8) | 0 | 1 (0.4) |
| AXO-CLI-LZD | 1 (0.8) | 0 | 1 (0.4) |
| AXO-CLI-LZD-OXA | 0** | 5 (3.8)** | 5 (2.0) |
| AXO-CLI-LEVO-OXA | 0 | 1 (0.8) | 1 (0.4) |
Fig. 1.
Relationship between serogroup, source of isolate and antimicrobial resistance of Listeria monocytogenes identified among the most numerous antimicrobial resistance profiles
AXO – ceftriaxone; OXA – oxacillin; CLI – clindamycin; RTE – ready-to eat food; FPE – food production environment