Stenotrophomonas maltophilia as an Emerging Ubiquitous Pathogen: Looking Beyond Contemporary Antibiotic Therapy

Abstract

Stenotrophomonas maltophilia is a commensal and an emerging pathogen earlier noted in broad-spectrum life threatening infections among the vulnerable, but more recently as a pathogen in immunocompetent individuals. The bacteria are consistently being implicated in necrotizing otitis, cutaneous infections including soft tissue infection and keratitis, endocarditis, meningitis, acute respiratory tract infection (RTI), bacteraemia (with/without hematological malignancies), tropical pyomyositis, cystic fibrosis, septic arthritis, among others. S. maltophilia is also an environmental bacteria occurring in water, rhizospheres, as part of the animals' microflora, in foods, and several other microbiota. This review highlights clinical reports on S. maltophilia both as an opportunistic and as true pathogen. Also, biofilm formation as well as quorum sensing, extracellular enzymes, flagella, pili/fimbriae, small colony variant, other virulence or virulence-associated factors, the antibiotic resistance factors, and their implications are considered. Low outer membrane permeability, natural MDR efflux systems, and/or resistance genes, resistance mechanisms like the production of two inducible chromosomally encoded β-lactamases, and lack of carefully compiled patient history are factors that pose great challenges to the S. maltophilia control arsenals. The fluoroquinolone, some tetracycline derivatives and trimethoprim-sulphamethaxole (TMP-SMX) were reported as effective antibiotics with good therapeutic outcome. However, TMP-SMX resistance and allergies to sulfa together with high toxicity of fluoroquinolone are notable setbacks. S. maltophilia's production and sustenance of biofilm by quorum sensing enhance their virulence, resistance to antibiotics and gene transfer, making quorum quenching an imperative step in Stenotrophomonas control. Incorporating several other proven approaches like bioengineered bacteriophage therapy, Epigallocatechin-3-gallate (EGCG), essential oil, nanoemulsions, and use of cationic compounds are promising alternatives which can be incorporated in Stenotrophomonas control arsenal.

Characterization of maltocin S16, a phage tail‐like bacteriocin with antibacterial activity againstStenotrophomonas maltophiliaandEscherichia coli

“…Stenotrophomonas maltophilia is a ubiquitous microbe in the environment (Ryan et al ). Most recently, the organism is being recognized as an important nosocomial pathogen associated with increasing morbidity and mortality (Brooke ; Adegoke et al ). Both environmental and clinical isolates of S. maltophilia are highly resistant to a wide range of commonly used antibiotics (Sánchez et al ; Sánchez ).…”

Stenotrophomonas maltophilia Meningitis in a Term Healthy Neonate: A Case Report and Literature Review

“…Populations at risk for S. maltophilia meningitis are typically immunocompromised patients, those who had neurosurgical procedures, preterm babies, and patients in need of prolonged hospitalization [2]. To our knowledge, only seven reports of S. maltophilia meningitis have been published to date, all of who had at least one of the above risk factors (Table 2).…”

“…S. maltophilia is now of rising importance since it is a multidrug resistant organism that is associated with high morbidity and mortality. It is known to cause a wide spectrum of serious infections, including bacteremia, endocarditis, ocular infections, urinary tract infections, skin and soft tissue infections, pyomyositis, sepsis, and meningitis [2]. S. maltophilia meningitis in pediatrics is very rare with only very few cases reported since 1977.…”

Panel 7 – Pathogenesis of otitis media – a review of the literature between 2015 and 2019

“…Stenotrophomonas maltophilia is a commensal Gram-negative bacterium that is associated with potentially life-threatening infections in immunocompromised individuals. However, recent information suggest that this organism has emerged as a novel pathogen also in immunocompetent individuals where, among other infections, it causes necrotizing OM [107]. Its ability to form biofilms are thought to increase its survival in the middle ear and treatment is complicated by its already high level of antibiotic-resistance.…”