Stenotrophomonas maltophilia endogenous endophthalmitis: clinical presentation, antibiotic susceptibility, and outcomes

Global mapping of antibiotic resistance rates among clinical isolates of Stenotrophomonas maltophilia: a systematic review and meta-analysis

INTRODUCTION

Infections caused by Stenotrophomonas maltophilia are clinically important due to its intrinsic resistance to a broad range of antibiotics. Therefore, selecting the most appropriate antibiotic to treat S. maltophilia infection is a major challenge.

AIM

The current meta-analysis aimed to investigate the global prevalence of antibiotic resistance among S. maltophilia isolates to the develop more effective therapeutic strategies.

METHOD

A systematic literature search was performed using the appropriate search syntax after searching Pubmed, Embase, Web of Science and Scopus databases (May 2023). Statistical analysis was performed using Pooled and the random effects model in R and the metafor package. A total of 11,438 articles were retrieved. After a thorough evaluation, 289 studies were finally eligible for inclusion in this systematic review and meta-analysis.

RESULT

Present analysis indicated that the highest incidences of resistance were associated with doripenem (97%), cefoxitin (96%), imipenem and cefuroxime (95%), ampicillin (94%), ceftriaxone (92%), aztreonam (91%) and meropenem (90%) which resistance to Carbapenems is intrinsic. The lowest resistance rates were documented for minocycline (3%), cefiderocol (4%). The global resistance rate to TMP-SMX remained constant in two periods before and after 2010 (14.4% vs. 14.6%). A significant increase in resistance to tigecycline and ceftolozane/tazobactam was observed before and after 2010.

CONCLUSIONS

Minocycline and cefiderocol can be considered the preferred treatment options due to low resistance rates, although regional differences in resistance rates to other antibiotics should be considered. The low global prevalence of resistance to TMP-SMX as a first-line treatment for S. maltophilia suggests that it remains an effective treatment option.

Triple Gram-negative bacterial endophthalmitis following intravitreal injection

PURPOSE

To describe a puzzling case of endophthalmitis caused by three unusual bacteria after intravitreal injection, its outcome, and underlying questions.

FINDINGS

A 70-year-old female patient was diagnosed with acute endophthalmitis following intravitreal aflibercept injection for age-related macular degeneration. A standard tap and inject procedure was performed. Microbiological analyses on the anterior chamber and vitreous samples yielded the presence of three non-fermenting Gram-negative rods: Pseudomonas stutzeri, Stenotrophomonas maltophilia, and Ochrobactrum anthropi. The outcome was favorable after intravitreal injections of vancomycin and ceftazidime, with an almost complete recovery of the visual acuity to its baseline level. No potential source of infection was identified.

CONCLUSION

Endophthalmitis following intravitreal injection can be caused by a wide variety of bacteria, including some rare Gram-negative species. They can sometimes co-exist in a single patient, but their virulence may vary greatly. Due to the variable antibiotic susceptibility and frequent multiresistance associated with non-fermenting Gram-negative rods, a prompt microbiological approach is required. Favorable outcome can be achieved with standard management.

Antimicrobial Susceptibility, Minimum Inhibitory Concentrations, and Clinical Profiles of Stenotrophomonas maltophilia Endophthalmitis

Stenotrophomonas maltophilia has been reported in various ocular infections, including keratitis, conjunctivitis, preseptal cellulitis, and endophthalmitis, all of which may lead to vision loss. However, the S. maltophilia strain is resistant to a wide variety of antibiotics, including penicillins, third-generation cephalosporins, aminoglycosides, and imipenem. In this study, we retrospectively reviewed the clinical characteristics, antibiotic susceptibility, antimicrobial minimum inhibitory concentrations (MICs), and visual outcomes for S. maltophilia endophthalmitis. The data of 9 patients with positive S. maltophilia cultures in a tertiary referral center from 2010 to 2019 were reviewed. Cataract surgery (n  =  8, 89%) was the most common etiology, followed by intravitreal injection (n  =  1, 11%). S. maltophilia’s susceptibility to levofloxacin and moxifloxacin was observed in 6 cases (67%). Seven isolates were resistant to sulfamethoxazole-trimethoprim (78%). The MIC₉₀ for S. maltophilia was 256, 256, 256, 8, 12, 12, 12, and 8 μg/mL for amikacin, cefuroxime, ceftazidime, tigecycline, sulfamethoxazole-trimethoprim, levofloxacin, galtifloxacin, and moxifloxacin, respectively. Final visual acuity was 20/200 or better in 5 patients (56%). Fluoroquinolones and tigecycline exhibited low antibiotic MIC₉₀. Therefore, the results suggest that fluoroquinolones can be used as first-line antibiotics for S. maltophilia endophthalmitis.

Advances in the Microbiology of Stenotrophomonas maltophilia

Stenotrophomonas maltophilia is an opportunistic pathogen of significant concern to susceptible patient populations. This pathogen can cause nosocomial and community-acquired respiratory and bloodstream infections and various other infections in humans. Sources include water, plant rhizospheres, animals, and foods. Studies of the genetic heterogeneity of S. maltophilia strains have identified several new genogroups and suggested adaptation of this pathogen to its habitats. The mechanisms used by S. maltophilia during pathogenesis continue to be uncovered and explored. S. maltophilia virulence factors include use of motility, biofilm formation, iron acquisition mechanisms, outer membrane components, protein secretion systems, extracellular enzymes, and antimicrobial resistance mechanisms. S. maltophilia is intrinsically drug resistant to an array of different antibiotics and uses a broad arsenal to protect itself against antimicrobials. Surveillance studies have recorded increases in drug resistance for S. maltophilia, prompting new strategies to be developed against this opportunist. The interactions of this environmental bacterium with other microorganisms are being elucidated. S. maltophilia and its products have applications in biotechnology, including agriculture, biocontrol, and bioremediation.

Clinical and Optical Coherence Tomography Angiographic Features in Patients with Postcataract Stenotrophomonas maltophilia Endophthalmitis

Purpose

To report the clinical presentations and optical coherence tomography (OCT) angiographic features of patients with postcataract surgery endophthalmitis due to Stenotrophomonas maltophilia. Methods. A retrospective observational study of 4 patients who developed S. maltophilia endophthalmitis after cataract surgery. Pars plana vitrectomy (PPV) was performed to control the infection. Patients were followed up for six months. Complete ophthalmological examination results were collected before and after PPV.

Results

Patients' response to PPV therapy was excellent and the infection was cured in all cases. OCTA showed that, at the one-month follow-up, the vascular density (VD) and perfusion density (PD) in the superficial capillary plexus (SCP) were significantly lower than those in healthy collateral eyes. As time went on, the SCP-VD and SCP-PD values gradually improved.

Conclusions

With early PPV, the infection caused by S. maltophilia can be cured. OCTA provides a quantitative noninvasive assessment to evaluate the severity and prognosis of patients with S. maltophilia endophthalmitis.

Clinical characteristics and prognostic factors of patients with Stenotrophomonas maltophilia infections

INTRODUCTION:

Stenotrophomonas maltophilia earlier had limited pathogenic potential, but now with growing degree of immunosuppression in general population, it is being recognized as an important nosocomial pathogen.

METHODOLOGY:

A retrospective 7 years study was carried out to determine the clinical characteristics of all patients with Stenotrophomonas infections, antibiotic resistance pattern, and risk factors associated with hospital mortality. All patients with Stenotrophomonas culture positivity were identified and their medical records were reviewed. Risk factor associated with hospital mortality was analyzed.

RESULTS:

A total of 123 samples obtained from 88 patients were culture positive. Most patients presented with bacteremia (45, 51%) followed by pneumonia (37, 42%) and skin and soft tissue infections (6, 7%). About 23 of 88 Stenotrophomonas infected patients had co-infection. Percentage resistance to cotrimoxazole; 8 (5.4%) was lower than that for levofloxacin; 18 (12%). Twenty-eight patients died during hospital stay. Intensive Care Unit admission (P = 0.0002), mechanical ventilation (P = 0.0004), central venous catheterization (P = 0.0227), urethral catheterization (P = 0.0484), and previous antibiotic intake (P = 0.0026) were independent risk factors associated with mortality.

CONCLUSION:

Our findings suggest that Stenotrophomonas can cause various infections irrespective of patient's immune status and irrespective of potential source. Thus, Stenotrophomonas should be thought of as potential pathogen and its isolation should be looked with clinical suspicion.

Resurgence of Global Opportunistic Multidrug-resistant Stenotrophomonas maltophilia

CONTEXT

Stenotrophomonas maltophilia is a known nosocomial pathogen which is intrinsically resistant to multiple antibiotics. In India, S. maltophilia infection has only few case reports.

AIM

To determine the incidence of S. maltophilia infection from clinical isolates based on the specimen type, antibiotic susceptibility pattern, and impact on outcome.

SETTINGS AND DESIGN

One-year retrospective study was done at a tertiary liver care center.

METHODS

Patients with S. maltophilia isolation in clinical samples were selected. Serial levels of serum procalcitonin and total leukocyte count were recorded. Environmental surveillance was done from the wards of S. maltophilia isolation as part of routine practice.

STATISTICAL ANALYSIS

Continuous data were compared using Kruskal-Wallis test/Mann-Whitney test. The categorical data were compared by Chi-square/Fisher's exact test, wherever necessary. Besides this, an appropriate analysis like survival was carried out at the time of data analysis.

RESULTS

One hundred isolates were obtained from eighty patients of six wards. The greatest number (44/100, 44%) were from the Liver Coma Intensive Care Unit and the lowest (3/100) from the day care. Isolation from the respiratory samples was 1.32% and bloodstream infection 0.6%. Of 100 isolates, 12 (12%) were resistant to both trimethoprim-sulfamethoxazole and levofloxacin.

CONCLUSION

S. maltophilia was effectively isolated from the hospital environment, with two of hand impression and three of water samples' positive. Patients with respiratory infection had most S. maltophilia isolates. Antibiotic susceptibility revealed more resistance than reported in this region.