. 2021 Oct 9;10(10):1226. doi: 10.3390/antibiotics10101226

Table 1.

Recommended treatment approach for Stenotrophomonas infection.

Agent	Line of Treatment	Notes on Clinical Use
Trimethoprim-Sulfamethoxazole (TMP-SMX)	First line	Increasing resistance amongst cystic fibrosis patients Optimized dosing essential (15–20 mg/kg TMP-component in divided doses every 6–8 h)
Fluoroquinolones	First line	Low resistance barrier Caution in deep-seated infections or anticipated duration of use >14 days Levofloxacin most studied—recommended dose 750 mg every 24 h, moxifloxacin a viable alternative
Tetracyclines	First line	Favorable tolerability profile and large volume of distribution to tissues Susceptibility generally retained in the context of TMP-SMX and/or levofloxacin resistance Minocycline preferred agent—200 mg loading dose, followed by 100 mg every 12 h Susceptibility of tigecycline and eravacycline mirror minocycline; tigecycline 100mg loading dose then 50 mg every 12 h; however, if S. maltophilia MIC > 0.5 µg/mL, then recommend 200 mg loading dose, then 100 mg every 12 h Low drug recovery from urine and lower serum levels should raise caution with treatment for bacteremia and urinary infections; utilization of high dosing regimens may be preferred in these circumstances
Cefiderocol	Salvage	Favorable reported MIC (minimum inhibitory concentration) data Limited to experimental and animal models Utility primarily in XDR ¹ isolates
Ceftazidime/Avibactam + Aztreonam	Salvage	Efficacy is largely in vitro Clinical evidence limited to case reports Susceptibility testing for combination therapy not routinely available Ceftazidime/Avibactam 2.5 gm every 8 h CONCURRENT Aztreonam 2 gm every 8 h (8 gm daily if septic shock) Used in XDR ¹ isolates
Combination therapy amongst first/second line agents and alternatives	Possible options	Lack of evidence to support routine clinical benefit or reduction in emergence of resistance Success limited to case reports/series Can be considered in deep seated/polymicrobial infections; still standard of care in endocarditis/endovascular disease
Polymyxins	Possible options	Susceptibility testing difficult to perform and concern for heterogenous resistance Use limited by toxicity and reported lower efficacy compared to preferred options Can be used as empiric therapy pending alternative options When used for pneumonia-intravenous and nebulized therapy recommended

¹ Extensively drug-resistant Stenotrophomonas species, defined by resistance by CLSI breakpoints to TMP-SMX, levofloxacin, and minocycline.