Volume 29, Number 8—August 2023
Research Letter
Case of Extensively Drug-Resistant Shigella sonnei Infection, United States
Hosoon Choi, Dhammika H. Navarathna, Brennon L. Harston, Munok Hwang, Brandon Corona, Ma Rowen San Juan, and Chetan Jinadatha
Table
Antimicrobial MICs and putative resistance genes of Shigella sonnei strain MB23166 from a case of XDR S. sonnei infection, United States*
| Antimicrobial | MIC | Interpretation | Putative resistance genes |
|---|---|---|---|
| First-line antimicrobial treatment† | |||
| Ciprofloxacin | ≥4 | R | qnrB19, gyrA (p.S83L) |
| Ceftriaxone | ≥64 | R | blaCTX-M-27 |
| Azithromycin |
≥256 |
R |
mph(A) |
| Alternative antimicrobial treatment† | |||
| Ampicillin | ≥32 | R | blaCTX-M-27 |
| Trimethoprim/sulfamethoxazole |
≥320 |
R |
sul1, sul2, dfrA1, dfrA17 |
| Other antimicrobials used for the patient before identification of XDR Shigella | |||
| Metronidazole | ≥256 | R | NA |
| Piperacillin/tazobactam | 64 | I | NA |
| Doxycycline |
24 |
R |
tet(A) |
| Potential antimicrobials for XDR Shigella | |||
| Fosfomycin | 1.5 | S | NA |
| Ertapenem | ≤0.5 | S | NA |
| Imipenem | ≤0.25 | S | NA |
| Meropenem | ≤0.25 | S | NA |
| Tigecycline | ≤0.5 | S | NA |
| Mecillinam (pivmecillinam) |
0.032 |
S |
NA |
| Other antimicrobials | |||
| Amoxicillin/clavulanic acid | 4 | S | NA |
| Cefotetan | ≤4 | S‡ | NA |
| Cefoxitin | ≤4 | S‡ | NA |
| Ceftizoxime | ≤1 | S‡ | NA |
| Amikacin | 4 | S‡ | NA |
| Gentamicin | ≤1 | S‡ | NA |
| Tobramycin | 2 | S‡ | NA |
| Nitrofurantoin | ≤16 | S | NA |
| Aztreonam | 4 | S | blaCTX-M-27 |
| Ampicillin/sulbactam | ≥32 | R | NA |
| Ticarcillin | ≥128 | R | blaCTX-M-27 |
| Piperacillin | ≥128 | R | blaCTX-M-27 |
| Cephalothin | ≥64 | R | NA |
| Cefazolin | ≥64 | R | NA |
| Cefuroxime | ≥64 | R | NA |
| Cefuroxime/axetil | ≥64 | R | NA |
| Cefpodoxime | ≥8 | R | NA |
| Cefotaxime | 16 | I | blaCTX-M-27 |
| Ceftazidime | ≥64 | R | blaCTX-M-27 |
| Cefepime | ≥64 | R | blaCTX-M-27 |
| Nalidixic acid | ≥32 | R | gyrA (p.D87G), gyrA (p.S83L) |
| Levofloxacin | ≥8 | R | NA |
| Moxifloxacin | ≥8 | R | NA |
| Norfloxacin | ≥16 | R | NA |
| Tetracycline | ≥16 | R | tet(A) |
| Chloramphenicol | 16 | I | NA |
*I, intermediate; NA, not applicable; R, resistant; S, susceptible; XDR, extensively drug-resistant. †According to 2017 Infectious Diseases Society of America guidelines (https://www.idsociety.org). ‡Although susceptible in vitro, not effective clinically for Shigella species according to Clinical and Laboratory Standards Institute Performance Standards for Antimicrobial Susceptibility Testing, 32nd edition(https://clsi.org).
Page created: June 07, 2023
Page updated: July 20, 2023
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