Table 2. FQ-resistance markers in NTS, reported by WGS.
The number of isolates sequenced is indicated by ‘n’. ‘Source’ indicates whether samples were of human (H) or animal (A) origin. The percentage of sequenced isolates containing FQ-resistance markers is reported under ‘% FQR markers’. The right panel of the table provides an overview of the identified (combinations of) FQ-resistance mechanisms. Each line represents a combination of FQ markers that was observed in the respective study. Mutations in gyrase (gyr) and topoisomerase IV (par) encoding genes are provided as resulting changes in residue, and presented per gene and per identified combination. na, Not available.
| Reference | Region or country | n | NTS serovar | Source | % FQR markers | FQ-resistance marker | ||||
|---|---|---|---|---|---|---|---|---|---|---|
| PMQR | Mutations in gyr and par | |||||||||
| gyrA | gyrB | parC | parE | |||||||
| [67] | Scotland | 290 | Typhimurium DT104 | H, A | 13 | – | Ser83Phe | – | – | – |
| – | Asp87G | – | – | – | ||||||
| – | Asp87Asn | – | – | – | ||||||
| [10] | Africa, Asia, Europe, Americas | 675 | Enteritidis | H, A | 0.15 | – | – | – | – | – |
| Africa | 496 | qnrS | – | – | – | – | ||||
| [69] | USA | 640 | 12 NTS serotypes | H | 3 | – | Asp87Tyr | – | – | – |
| – | Ser83Phe | – | – | – | ||||||
| – | Asp87Tyr+Ser83Phe | – | Ser80Ile | – | ||||||
| qnrS | – | – | – | – | ||||||
| qnrB | – | – | – | – | ||||||
| qnrB+oqxA+oqXB | – | – | – | – | ||||||
| [68] | USA (New York and Washington) | 90 | Typhimurium | H | 7 | qnrS | – | – | – | – |
| oqxA, oqxB | Asp87Tyr | – | – | – | ||||||
| oqxA, oqxB | Ser83Tyr | – | – | – | ||||||
| qnrB | – | – | – | – | ||||||
| oqxA, oqxB | Asp87Asn | – | – | – | ||||||
| – | Asp87Asn | – | – | – | ||||||
| [66] | USA, Europe | 659 | 4,[4],12:i:- | A | 5 | qnrB, qnrS | – | – | – | – |
| [64] | Morocco, unknown | 153 | Chester | H | 54 | qnrS, qnrB | – | – | – | – |
| [81] | South Asia, South-East Asia and Oceania | 115 | Weltevreden | H, A | na | qnrD, qnrS | – | – | – | – |
| oqxA, oqxB | – | – | – | – | ||||||
| [80] | Southern China | 44 | Weltevreden | H | 5 | qnrD | – | – | – | – |
| qnrS | – | – | – | – | ||||||
| [65] | Chile | 30 | Enteritidis | A | 7 | qnrB | – | – | – | – |
| 2018* | Vietnam | na | Typhimurium | H | na | qnrS | Asp87Asn | – | – | – |
*S. Baker, personal communication (2018).