Stenotrophomonas Maltophilia Research Articles

Accelerated electrochemical antibiotic susceptibility testing using disposable electrodes and Resazurin.

A bench study comparing the performance of a novel test lung with a conventional model.

We report the discovery of 4'-thiothymidine (4'sT), a sulfur-containing nucleoside antibiotic produced by the nematode symbiont Photorhabdus asymbiotica. 4'sT exhibits antibacterial activity against Escherichia coli, Stenotrophomonas maltophilia, and Klebsiella pneumoniae. The production of 4'sT was increased in rifampicin-resistant mutants. Heterologous expression of the radical SAM enzyme-containing gene cluster confirmed its biosynthetic origin. Resistant mutants mapped to tdk, which encodes thymidine kinase in the thymidine salvage pathway. Mechanistic studies revealed that 4'sT is a prodrug activated via the thymidine salvage pathway and incorporated into DNA, where it inhibits replication and triggers the SOS response. Clinical E. coli isolates were resistant, but inhibition of de novo thymidylate synthesis with trimethoprim rendered them highly susceptible, indicating that strain-selective activity is governed by differences in thymidine metabolism. These findings highlight the role of metabolic context in determining antibiotic selectivity and demonstrate the utility of rifampicin resistance for assessing silent biosynthetic gene clusters to discover new antimicrobial compounds.IMPORTANCEIntroducing novel antibiotics is essential to counter the spread of drug-resistant pathogens. Here, we report the discovery of 4'-thiothymidine (4'sT), a nucleoside antibiotic from the nematode symbiont Photorhabdus asymbiotica, identified through activation of a silent biosynthetic gene cluster. 4'sT features an unusual 4'-thiosugar moiety. We identified its biosynthetic gene cluster, including a radical SAM enzyme presumably involved in sulfur incorporation. 4'sT exhibits strain-selective activity that is governed by differences in thymidine metabolism rather than variations in the molecular target. These findings expand our knowledge of antibiotics with unusual selective activity.

Stenotrophomonas maltophilia (S. maltophilia) is a multidrug-resistant opportunistic pathogen. There are an increasing number of case reports on S. maltophilia infections in recent years, and the species is becoming a public health concern. Many studies have focused on profiling and pangenome of the species, particularly on their antibiotic resistance and virulence genes. However, there is a lack of studies on mobile genetic elements (MGEs), a subset of pangenome that significantly contributes to the diversity, stability, and plasticity of a population. In this study, 20 genomes of S. maltophilia were downloaded from the NCBI Genome database. The genomes were subjected to profiling of MGEs, their impact on the population structures, and the evaluation of evolutionary trends of the core genomes. The cataloguing of MGEs indicated active horizontal gene transfer events in the S. maltophilia’s population. Multiple virulence and drug resistance genes were predicted within and outside of the MGEs. We observed multiple chromosomal rearrangements in the genomes, most likely caused by MGEs, affecting up to approximately 50% of a single genome sequence. A high number of linkage disequilibrium sites were also predicted in the core genomes. This study provides insights into stability in the core and plasticity in the accessory regions in the S. maltophilia population.

Stenotrophomonas maltophilia causes severe infections with limited treatment options. Aztreonam-avibactam demonstrates in vitro activity against this important pathogen with an MIC90 of 4/4 mg/L, but the efficacy of this agent is unknown. Herein, we used the neutropenic thigh infection model to assess in vivo efficacy against S. maltophilia. S. maltophilia isolates (n = 27) resistant to aztreonam (MIC ≥64 mg/L) and with aztreonam-avibactam MICs between 2/4 and >16/4 mg/L were examined using a neutropenic murine thigh infection model. Pharmacokinetic studies were performed for the development of a human-simulated regimen (HSR) of aztreonam-avibactam (1.5-0.5 g q6h, 3h infusion) to mimic the human free plasma exposure profile. Efficacy of the aztreonam-avibactam HSR was defined as ≥1 log10 cfu/thigh reduction at 24 h compared with baseline bacterial burden. Among investigated isolates, the mean baseline bacterial burden in the model was 6.22 ± 0.16 log10 cfu/thigh. Without treatment, isolates grew on average to 7.81 ± 0.44 log10 cfu/thigh at 24 h. With aztreonam-avibactam HSR administration, 78% (7/9), 67% (6/9), 29% (2/7) and 0% (0/2) reached ≥1 log10 cfu/thigh reduction at MICs of 2/4, 4/4, 8/4 and ≥16/4 mg/L, respectively. Aztreonam-avibactam HSR demonstrated in vivo efficacy against the majority of S. maltophilia isolates with MIC ≤4/4 mg/L in a neutropenic murine thigh infection model. These results provide decision support to standards development organizations for determination of susceptibility breakpoints for aztreonam-avibactam against S. maltophilia.

BackgroundThe World Health Organization has identified Stenotrophomonas maltophilia (SM) as a high-risk antibiotic-resistant pathogen. Notably, determining the effectiveness of current antibiotics against SM is challenging, leading to improper therapy and the spread of resistance. This study assessed how an artificial intelligence-clinical decision support system (AI-CDSS) utilizing mass spectrometry data to predict resistance enhances prescribing decisions and boosts survival.MethodsThis randomized controlled trial (ISRCTN16278872) involved 400 healthcare professionals, with 1,600 SM infections randomized in a 1:1 ratio to either standard practice (control, n = 800) or an AI-CDSS predicting resistance 1 day earlier (intervention, n = 800). Outcomes were assessed by healthcare professionals using structured surveys on days 3, 5, 7, and 14 after treatment initiation. Patient mortality was analyzed over a 14-day follow-up period.ResultsThe AI-CDSS group demonstrated significantly higher confidence (p < 0.001) in antibiotic prescription, decision-making efficiency, and appropriate antibiotic selection across all time points. Mortality was lower in the AI-CDSS group (92/800, 11.5%) than in the control group (121/800, 15.1%) (p = 0.03). Effective antibiotic choices and reliance on the AI-CDSS during the critical early stages of treatment contributed to improved patient outcomes.ConclusionsImplementation of the AI-CDSS in a clinical trial setting enhances prescribing confidence, improves decision-making and antibiotic selection, reduces mortality, and demonstrates clinical potential.Trial registrationISRCTN, ISRCTN16278872. Registered 28 June 2024, https://www.isrctn.com/ISRCTN16278872.Supplementary InformationThe online version contains supplementary material available at 10.1186/s13012-025-01453-4.

Guideline for antimicrobial treatment of multidrug-resistant Gram-negative infections: practice recommendations of the Brazilian Society of Infectious Diseases.

Introduction. Puerperal sepsis is still a life-threatening obstetric complication worldwide, even in settings with advanced medical resources. Clinical manifestations may be subtle and atypical during pregnancy and the puerperium, leading to delays in recognition and treatment. Multidrug-resistant organisms such as Stenotrophomonas maltophilia further complicate management, often requiring aggressive multidisciplinary approaches. Case presentation. We present a case of vaginal hematoma and peripartum infection with Stenotrophomonas maltophilia accompanied by multiple organ dysfunction syndrome. Conclusions. The presence of pelvic contusion leads to sepsis caused by multiple infections in the peripartum period and can significantly increase the incidence of diseases associated with bleeding, infection, surgery, and blood product transfusions. The clinical condition of the patient may be worsened in the presence of pre-existing conditions prior to pregnancy.

This study explores the interactions among bio inoculants and zinc nano-fertilizer and their combined effects on strawberry growth and yield metrics in an effort to improve agricultural methods. The present investigation was carried out, with the objective to assess the impact of nano zinc, the viability of co-inoculating AMF and selenobacteria, as well as their potential interactions on morphological and nutritional traits of strawberry. Combinations arranged in a randomized complete block design comprising two levels of AM fungi and three levels of selenobacteria and nano zinc oxide each. The interaction of AM fungi × selenobacteria × nano zinc oxide application reveals that maximum height of plants (25.31 cm) and maximum number of runners per plant (36.75) were recorded in the interaction, where plants were rhizoinoculated with AM fungi, selenobacterial strain Stenotrophomonas maltophilia and foliar application of nano zinc oxide @ 200 ppm. Whereas, increase in the number of leaves with corresponding enhanced leaf area were produced in the interaction, AM fungi, selenobacterial strain Stenotrophomonas maltophilia and foliar application of nano zinc oxide @ 100ppm) alongwith maximum leaf phosphorus (0.46 %) and manganese content (46.28%).

IntroductionEmerging evidence suggests that the blood microbiome may influence the progression of HIV infection and immune restoration. This study aims to comprehensively characterize blood microbiota alterations associated with HIV infection and antiretroviral therapy (ART), and to evaluate their potential as microbial indicators for assessing infection status and immune restoration.MethodsWe recruited 91 participants, including 31 treatment-naïve HIV-infected individuals, 30 ART-treated individuals with undetectable viral loads, and 30 healthy controls. Blood samples were collected for metagenomic sequencing and immunological profiling.ResultsHIV infection profoundly disrupted blood microbiota diversity and composition, with a marked reduction in α-diversity and enrichment of opportunistic pathogens such as Pseudomonas aeruginosa, Acinetobacter baumannii and Stenotrophomonas maltophilia, alongside depletion of beneficial taxa like Bifidobacterium longum. ART partially restored microbial diversity but did not fully reestablish a healthy microbiota. Correlation analysis revealed that Acinetobacter pittii, Xanthomonas campestris and Diaphorobacter nitroreducens were significantly associated with viral load, suggesting their potential role in HIV progression. Additionally, after ART, Acinetobacter junii and Pseudomonas putida were significantly correlated with the CD4/CD8 ratio, indicating their potential role in immune restoration.DiscussionThese findings provide new insights into the interactions between blood microbiota and HIV progression. The identified blood microbiota may serve as potential indicators for evaluating HIV infection status and treatment efficacy, offering a basis for microbial-based diagnostic and therapeutic strategies.

Knowledge of novel and revised bacterial taxonomy facilitates routine operations in the medical microbiology laboratory and communication with important stakeholders. Notable new gram-positive taxa accepted in 2024 include the clinically significant Staphylococcus brunensis sp. nov., as well as Streptococcus suis subsp. hashimotonensis subsp. nov., which can be delineated from other Streptococcus suis subsp. by possession of the Lancefield group A antigen. Four novel Enterobacterales species are discussed, plus a novel eighth family Gallaecimonadaceae. One of these, Providencia huashanensis sp. nov. is clinically significant and harbors multiple genetic determinants that encode antimicrobial resistance mechanisms. Stenotrophomonas forensis sp. nov., derived from specimen transport medium, was determined to be a distinct component within the Stenotrophomonas maltophilia complex. Bartonella tamiae sp. nov. has become officially recognized as the agent of the first culture-confirmed bartonelloses in Thailand. Significant taxonomic revisions include the return of Chlamydophila caviae to the Chlamydia genus, creation of the novel Metaclostridioides genus for Clostridioides mangenotii, and reclassification of two Kocuria spp. into two subspecies of Kocuria rosea. Clinical updates are provided for 13 past Journal of Clinical Microbiology taxonomic compendium entries for which extensive clinical data were not previously available. These include potential clinical significance for non-vaginalis species of the Gardnerella genus and for Pandoraea commovens in a non-cystic fibrosis setting.

Recognizing and updating bacterial names is key to communication between the veterinary clinical microbiology laboratory, veterinarians, and clients. Moraxella oculi sp. nov., distinct from Moraxella bovis and Moraxella bovoculi, was isolated from a cow with infectious bovine keratoconjunctivitis. Several respiratory pathogens were recognized, including Neisseria leonii sp. nov. described from rabbits, Mannheimia indoligenes sp. nov. described from cattle in Europe, and Moraxella haemolytica sp. nov. described from a goat in China. Stenotrophomonas forensis sp. nov. is a novel designation within the Stenotrophomonas maltophilia complex associated with isolates derived from horses. New additions to the Campylobacter genus included Campylobacter californiensis sp. nov., recovered from bovine feces during a raw milk-associated outbreak of campylobacteriosis in humans. Taxonomic revisions were most notable in Gram-positive organisms. A species within genus Jeotgalicoccus has been renamed, and the subspecies designation Kocuria rosea subsp. polaris comb. nov. has been created. Streptococcus suis was revised to Streptococcus suis subsp. suis subsp. nov. in recognition of the initial description of Streptococcus suis subsp. hashimotonensis subsp. nov., which was isolated from people in Japan with bite wounds from boars. Chlamydophila caviae, which causes respiratory disease and abortion in guinea pigs and is zoonotic, has been revised to Chlamydia caviae comb. nov.

The aim of this study was to investigate the prevalence of intestinal colonization by major multidrug-resistant (MDR) bacteria and fungi in patients with hematological malignancies (HM) and its relationship with subsequent bloodstream infections (BSIs). The study was performed between December 2023 and June 2024 at the University Hospital "Saint Marina", Varna, Bulgaria. A total of 180 HM patients were screened for intestinal colonization by 3rd generation cephalosporin-resistant (3rdGCephR) and carbapenem-resistant (CR) Enterobacterales, Pseudomonas aeruginosa, Stenotrophomonas maltophilia, Vancomycin-Resistant Enterococci (VRE) and Candida sp. according to our own protocol. Blood cultures were taken according to clinical indications. Multiplex PCR was used to detect beta-lactamase genes in all invasive Enterobacterales isolates. A total of 100 patients (55.6%) were colonized by one or more of the screened agents. Among these, 88 patients were MDR carriers (48.9%, 88/180) and the highest colonization rates were found for CR Klebsiella pneumoniae (CRKP) (42%), Candida sp. (34%), VRE (25%) and 3rdGCephR Escherichia coli (23%). A total of 29 patients (16.1%; 29/180) developed BSIs, with K. pneumoniae responsible for 44.8%. Of these, 76.9% (10/13) were CR and blaNDM positive isolates. Related BSIs were diagnosed in 57.9% of the MDR carriers with BSIs (11/19). The related BSIs percentage according to the colonizing agent was 21.4% for CRKP (9/42), 7.1% for 3rdGCephR K. pneumoniae (1/14) and 25% for P. aeruginosa (1/4). CRKP colonization was significantly higher among patients with CRKP BSIs than those with non-CRKP BSIs (P < 0.001). The MDR intestinal colonization, specifically by CRKP is an important source for subsequent BSIs in this high-risk patient population.

Bioconversion for ursodeoxycholic acid using β-cyclodextrin included-chenodeoxycholic acid via immobilized cells of Xanthomonas maltophilia.

Sulfamethoxazole/trimethoprim is utilized to treat various infections, but its use can be limited by hyperkalaemia. Sodium zirconium cyclosilicate is a potassium binder, which has been shown to lower potassium in chronic kidney disease. To determine the safety and efficacy of sodium zirconium cyclosilicate for patients experiencing sulfamethoxazole/trimethoprim-induced hyperkalaemia. Patients receiving treatment with sulfamethoxazole/trimethoprim and sodium zirconium cyclosilicate therapy concomitantly for at least 48 h between 2021 and 2024 were identified. Efficacy was evaluated by potassium change from baseline, proportion of patients achieving normokalaemia by 24 and 48 h, and time to potassium normalization. Safety was assessed by evaluating hypokalaemia occurrence while on sodium zirconium cyclosilicate therapy. There were 22 patients included. The median total daily dose of sulfamethoxazole/trimethoprim was 960 mg or 15 mg/kg/day. Fifteen patients (68%) were treated for confirmed Stenotrophomonas maltophilia or Pneumocystis pneumonia infections. Eight patients (36%) received a loading dose of sodium zirconium cyclosilicate 10 g three times daily for 48 h prior to receiving 10 g daily. The median difference in potassium at baseline and the end of sodium zirconium cyclosilicate therapy was 0.9 mmol/L. Fourteen patients of 22 (64%) and 19 of 21 patients (90%) achieved normokalaemia by 24 and 48 h, respectively. The median time to potassium normalization was 23.5 h. There were no instances of hypokalaemia while on sodium zirconium cyclosilicate therapy. Sodium zirconium cyclosilicate was efficacious at lowering elevated potassium in patients receiving sulfamethoxazole/trimethoprim therapy without inducing hypokalaemia. This suggests sodium zirconium cyclosilicate may be considered in patients with treatment-limiting hyperkalaemia due to sulfamethoxazole/trimethoprim, especially when sulfamethoxazole/trimethoprim is preferred therapy.

PurposeChemotherapy remains the primary treatment for haematological malignancies (HMs). While recent therapeutic advances have improved patient survival, treatment-induced immunosuppression and prolonged neutropenia significantly elevate the risks of bloodstream infection (BSI), contributing to higher mortality. This study identifies risk factors for BSI in pediatric HM patients, aiming to establish evidence-based protocols for infection prevention and risk stratification, thereby informing targeted healthcare policies to reduce complications and improve treatment outcomes.Patients and MethodsWe retrospectively analyzed 682 pediatric HM patients presenting with fever at our institution, including 98 BSI-confirmed cases.Results were statistically compared across multiple aspects.ResultsPediatric HM patients with bloodstream infection showed significantly higher AML prevalence (47.96% vs 33.22%, P = 0.005) and Gram-negative bacteria predominance (66.33%), notably Escherichia coli (E. coli) (27.55%). Stenotrophomonas maltophilia infection rates were significantly higher in lymphoma patients than in other hematological malignancies (P < 0.05). Multivariable analysis identified four modifiable risk factors: peak body temperature (OR = 5.468, 95% CI 3.407–8.775, P < 0.001), duration of neutropenia (OR = 1.181, 95% CI 1.120–1.245, P < 0.001), febrile neutropenia (OR = 8.193, 95% CI 3.574–18.780, P < 0.001), and invasive procedures (OR = 4.265, 95% CI 1.920–9.474, P < 0.001).ConclusionTo reduce BSI complications in pediatric HM patients, we recommend implementing risk-stratified temperature protocols and strict neutropenia control (≤7 days), emphasizing rigorous clinical criteria for invasive procedures (PICC). These findings provide an evidence base for healthcare policies aimed at reducing infection-related mortality through optimized treatment protocols and enhanced clinical care standards.

Bacterial locomotion is integral to acquiring resources and getting access to new niches. Swarming, a type of motility where flagellated bacteria cooperatively move together across a semi solid surface, is one example of how bacteria can colonize new territories. This collective behavior is temporally and spatially orchestrated, requiring task specialization of community members. In this study, we paired a swarming bacterium, Paenibacillus amylolyticus, with a non-swarmer, Stenotrophomonas maltophilia, to investigate the impact on fitness of each strain. In dual-species conditions, the community swarm became significantly thicker and improved the ability of S. maltophilia to range into new territories. Swarming enabled P. amylolyticus to cross barriers of antimicrobials, whereas the thicker, dual-species swarm did not empower S. maltophilia to cross. Comparative studies of population dynamics revealed that over time, monospecies swarms of P. amylolyticus entered a state unable to grow despite still showing reductase activity. However, in a dual-species swarm, S. maltophilia rescued P. amylolyticus from this state. This rescue is attributed to the pH stabilization that occurs in this two-species combination, where S. maltophilia alkalizes the environment, thereby providing a more favorable environment for P. amylolyticus.

Stenotrophomonas maltophilia is an emerging multidrug-resistant pathogen increasingly associated with urinary tract infections (UTIs). This report the isolation of S. maltophilia from a full-term pregnant woman in Al-Bayda City, Libya, who presented with symptomatic UTI. Antimicrobial susceptibility testing was performed using both broth microdilution and the automated Render MA120 system. The isolate exhibited resistance to multiple antibiotic classes, with statistically significant differences in susceptibility patterns (p &lt; 0.001). Notably, nitrofurantoin and rifampin demonstrated unexpected in vitro activity, suggesting potential therapeutic alternatives. The patient was initially treated empirically with Trimethoprim/Sulfamethoxazole, but her symptoms persisted. Following targeted therapy with Ceftazidime and supportive care, clinical improvement was achieved. This report underscores the importance of early identification, antimicrobial stewardship, and region-specific surveillance in managing resistant infections during pregnancy, while also highlighting the need to balance maternal treatment efficacy with fetal safety. Keywords: Urinary tract infection; pregnancy; Stenotrophomonas maltophilia; multidrug resistance; antibiotic susceptibility; Libya; case report; maternal-fetal outcomes; antimicrobial stewardship; emerging uropathogen

Stenotrophomonas maltophilia is an emerging, multidrug-resistant pathogen increasingly associated with nosocomial infections, particularly in immunocompromised patients such as those undergoing allogeneic hematopoietic stem cell transplantation or affected by oncological diseases. Therapeutic options are limited due to intrinsic and acquired resistance mechanisms, including β-lactamases and efflux pumps. Although minocycline and trimethoprim-ulfamethoxazole are standard treatments, recent evidence suggests that eravacycline, a novel fluorocycline, may be effective in vitro, though clinical data remain scarce. Two cases of S. maltophilia bloodstream infection (BSI) in immunocompromised patients were reviewed. Both patients received eravacycline as part of combination therapy, following microbiological identification of the pathogen. Clinical course, microbiological outcomes, and antibiotic regimens were analyzed. Both patients, affected by acute myeloid leukemia and cholangiocarcinoma, developed S. maltophilia BSI after prolonged exposure to broad-spectrum antibiotics. Eravacycline (1 mg/kg every 12 hours) was included in both regimens. Blood cultures cleared within 48 hours in both cases. One patient died due to fungal complications, but S. maltophilia BSI was microbiologically controlled in both. These findings suggest a potential role for eravacycline in treating S. maltophilia BSI when standard options are limited. Further clinical studies are needed to establish efficacy and appropriate therapeutic use.

Methylparaben, as an environmental contaminant, compromises water disinfection under real conditions.