Table 2.
Modifications in efflux pump regulators in isolates with the EPO phenotype.
| Gene sequence | Type of Modification | Total (n=90) | HNCH (n=50) | HAL (n=40) | Modifications |
|---|---|---|---|---|---|
| MexAB-OprM regulators | |||||
| mexR | No mutationa | 39 | 21 | 18 | — |
| Amino acid substitution | 42 | 23 | 19 | V126E (39)/L131P (1)/V126E, L131P (1)/V126E, P143L (1) | |
| Amino acid deletion | 0 | 0 | 0 | ||
| Amino acid insertion | 0 | 0 | 0 | — | |
| Frameshift | 0 | 0 | 0 | — | |
| No amplification | 9 | 6 | 3 | — | |
| Stop | 0 | 0 | 0 | — | |
| nalC | No mutation | 10 | 4 | 6 | — |
| Amino acid substitution | 77 | 43 | 34 | G71E, S209R (54)/G71E, A145V, S209R (5)/G71E, S209R, P210L (5)/G71E (4)/ G71E, A186T (4)/G71E, D79R, S209R (2)/G71E, H150Q, M151P, D152E, E153R, (1)/G71E, E153Q (1)/S209R (1) | |
| Amino acid deletion | 0 | 0 | 0 | — | |
| Amino acid insertion | 0 | 0 | 0 | — | |
| Frameshift | 1 | 1 | 0 | Δnt234–243 + G71E | |
| No amplification | 2 | 2 | 0 | — | |
| Stop | 0 | 0 | 0 | — | |
| nalD | No mutation | 64 | 35 | 29 | — |
| Amino acid substitution | 8 | 6 | 2 | T188A (4)/L44P (1)/D187S (1)/L194R (1)/Q134H, Q142H, A145P, D147H, E148K, C149R, H154P, R160K, D176E, D185Y, G206S, S209I (1) | |
| Amino acid deletion | 0 | 0 | 0 | — | |
| Amino acid insertion | 0 | 0 | 0 | — | |
| Frameshift | 16 | 8 | 8 | Δnt397–398 (7)/Δnt263–279 (6)/Δnt391 (2)/Δnt451–461 (1) | |
| No amplification | 2 | 1 | 1 | ||
| Stop | 0 | 0 | 0 | — | |
| MexEF-OprN regulators | |||||
| mexT | No mutationb | 82 | 47 | 35 | — |
| Amino acid substitution | 3 | 1 | 2 | D290E (1)/V269E (1)/G148A, G238R, A249P (1) | |
| Amino acid deletion | 0 | 0 | 0 | — | |
| Amino acid insertion | 0 | 0 | 0 | — | |
| Frameshift | 0 | 0 | 0 | — | |
| No amplification | 5 | 2 | 3 | — | |
| Stop | 0 | 0 | 0 | — | |
| mexS | No mutationb | 50 | 31 | 19 | — |
| Amino acid substitution | 3 | 1 | 2 | V73A (2)/ G224S (1) | |
| Amino acid deletion | 0 | 0 | 0 | — | |
| Amino acid insertion | 0 | 0 | 0 | — | |
| Frameshift | 0 | 0 | 0 | — | |
| No amplification | 37 | 18 | 19 | — | |
| Stop | 0 | 0 | 0 | — | |
HNCH: Hospital Nacional Cayetano Heredia, HAL: Hospital Arzobispo Loayza,
In bold are both marked relevant modifications as well as amino acid change patterns previously described by Quale et al.26. The slanted line (/) separates different patterns of modifications.
The symbol Δnt means nucleotide deletion being noted the first and last nucleotides deleted.
The amino acid changes located after a frameshift are numbered following the sequence of the wild type strain without considering the presence of this frameshift, and therefore do not represent the protein produced and are only reported for facilitating epidemiological interpretations.
In parenthesis, the number of each specific alteration or combined alterations described. In all cases if a relevant modification was found the sequences are listed in this section, irrespectively of the remaining modifications detected.
aIn isolates in which no mutation was observed, the MexAB-OprM regulator sequences were identical to those of P. aeruginosa PAO1 (GenBank: AE004091.2).
bIn all isolates in which PCR amplification was obtained, the mexS and mexT genes were identical to those of P. aeruginosa PA14 (GenBank: CP000438).