Acute upper airway obstruction caused by Stenotrophomonas maltophilia soft tissue infection

Comparative In Vivo Antibacterial Activity of Human-Simulated Exposures of Cefiderocol and Ceftazidime against Stenotrophomonas maltophilia in the Murine Thigh Model

Cefiderocol is a novel siderophore cephalosporin that utilizes bacterial ferric iron transports to cross the outer membrane. Cefiderocol shows high stability against all classes of β-lactamases, rendering it extremely potent against carbapenem- and multidrug-resistant Gram-negative organisms. Using a neutropenic murine thigh model, we compared the efficacies of human-simulated exposures of cefiderocol (2 g Q8H 3 h infusion) and ceftazidime (2 g Q8H 2 h infusion) against Stenotrophomonas maltophilia, an emerging opportunistic Gram-negative organism associated with serious and often fatal nosocomial infections. Twenty-four S. maltophilia isolates were studied, including isolates resistant to ceftazidime, trimethoprim-sulfate, and/or levofloxacin. The thighs were inoculated with bacterial suspensions of 10⁸ CFU/mL and the human-simulated regimens were administered over 24 h. Efficacy was measured as the change in log₁₀CFU/thigh at 24 h compared with 0 h controls. Cefiderocol human-simulated exposure demonstrated potent bacterial killing; mean bacterial reduction at 24 h was -2.67 ± 0.68 log₁₀CFU/thigh with ≥ 2 log-reduction achieved in 21 isolates (87.5%) and ≥ 1 log-reduction achieved in the remaining three isolates (12.5%). In comparison, ceftazidime human-simulated exposure produced mean bacterial reduction of -1.38 ± 1.49 log₁₀CFU/thigh among 10 ceftazidime-susceptible isolates and mean bacterial growth of 0.64 ± 0.79 log₁₀CFU/thigh among 14 ceftazidime-non-susceptible isolates. While ceftazidime showed modest efficacy against most susceptible isolates, humanized cefiderocol exposures resulted in remarkable in vivo activity against all S. maltophilia isolates examined, inclusive of ceftazidime-non-susceptible isolates. The potent in vitro and in vivo activity of cefiderocol supports the development of this novel compound for managing S. maltophilia infections.

Stenotrophomonas maltophilia: emerging disease patterns and challenges for treatment

Stenotrophomonas maltophilia is a ubiquitous organism associated with opportunistic infections. In the immunocompromised host, increasing prevalence and severity of illness is observed, particularly opportunistic bloodstream infections and pneumonia syndromes. In this article, the classification and microbiology are outlined, together with clinical presentation, outcomes and management of infections due to S. maltophilia. Although virulence mechanisms and the genetic basis of antibiotic resistance have been identified, a role for standardized and uniform reporting of antibiotic sensitivity is not defined. Infections due to S. maltophilia have traditionally been treated with trimethoprim-sulfamethoxazole, ticarcillin-clavulanic acid, or fluoroquinolone agents. The use of combination therapies, newer fluoroquinolone agents and tetracycline derivatives is discussed. Finally, measures to prevent transmission of S. maltophilia within healthcare facilities are reported, especially in at-risk patient populations.

Therapeutic options for Stenotrophomonas maltophilia infections beyond co-trimoxazole: a systematic review

BACKGROUND

Stenotrophomonas maltophilia has emerged as an important opportunistic pathogen, causing infections whose management is often problematic due to its inherent resistance to many antibiotics, making co-trimoxazole the main therapeutic option. However, there are cases in which either due to antimicrobial resistance or allergic reactions and intolerance to co-trimoxazole this antibiotic cannot be administered. We sought to evaluate the available clinical evidence regarding potentially effective alternative antibiotics for the treatment of S. maltophilia infections.

METHODS

The literature search was performed in the PubMed and Scopus databases. The search string used was 'Stenotrophomonas maltophilia OR Xanthomonas maltophilia'.

RESULTS

Thirty-one case reports and 5 case series were retrieved including a total of 49 patients with a variety of infections. Twenty of 49 cases (40.8%) were treated with ciprofloxacin as monotherapy or in combination with other antibiotics; 12 of 49 cases (24.5%) were treated with ceftriaxone- or ceftazidime-based regimens; and 6 of 49 cases (12.2%) were treated with ticarcillin- or ticarcillin/clavulanate-based regimens. The cure or improvement rates were 18 cases (90%), 8 (75%) and 4 (66.7%), respectively. The remaining 11 patients received various antimicrobials including aminoglycoside-based regimens, carbapenems, levofloxacin, chloramphenicol, aztreonam, minocycline and other beta-lactams.

CONCLUSIONS

The limited available data suggest that ciprofloxacin, ceftazidime or ceftriaxone, and ticarcillin/clavulanate, alone or in combination with other antibiotics, may be considered as alternative options beyond co-trimoxazole.