Infectious Keratitis Caused by Stenotrophomonas maltophilia and Yeast Simultaneously

Clinical and Microbiological Spectra and Therapeutic Outcomes of Polymicrobial Keratitis

PURPOSE

The aim of this study was to evaluate the risk factors, microbiology, and treatment outcomes of polymicrobial keratitis (PMK).

METHODS

We retrospectively analyzed 65 patients diagnosed with PMK between 2016 and 2019. The clinical and microbiological characteristics and outcomes were evaluated. The primary outcome measure was clinical resolution of keratitis. Absolute success (group A) was defined as resolution of infection with medical treatment, qualified success (group B) was resolution with medical therapy and additional minor procedures, and failure (group C) was defined as worsening of infection and presence of corneal melting or perforation requiring therapeutic penetrating keratoplasty or evisceration.

RESULTS

Of 4764 cases of microbial keratitis, PMK was identified in 65 eyes of 65 patients (1.36%). Infiltrate was central in 60% (39 eyes). Predisposing factors were higher in group C and included uncontrolled diabetes mellitus in 25% (7/28), history of trauma/foreign body in 57.1% (16/28), and poor presenting visual acuity (0.9 for group A vs. 1.79 for group B vs. 3.00 logarithm of the minimum angle of resolution for group C; P = 0.02). Microbiological profiling revealed that a majority (95%: 62/65) had bacterial with fungal keratitis. High fluoroquinolone resistance was noted (57%; 34/59). Absolute success was achieved in 28.3% (17/60), qualified success in 16.6% (10/60), and treatment failure was noted in 55% (33/60). The final best corrected visual acuity in group A was significantly better than that in group B and C (0.44 vs. 3.00 vs. 2.78; P < 0.001).

CONCLUSIONS

PMK is extremely rare but responds poorly to medical therapy. Bacterial with fungal etiology is predominant. Early surgical intervention to improve overall outcome is advocated.

Clinical Features and Management of Stenotrophomonas Maltophilia Keratitis

Introduction

Stenotrophomonas maltophilia keratitis is an uncommon infectious disease of the cornea. The clinical features, antibiotic susceptibility, and clinical outcomes of S. maltophilia keratitis were investigated in this study.

Methods

Between January 2015 and February 2020, the medical records of 16 patients with culture-proven S. maltophilia-associated infectious keratitis were retrospectively reviewed. Clinical data were analyzed regarding risk factors, clinical presentation, antibiotic susceptibility, and clinical outcomes.

Results

The average age of the patients was 56.24 ± 24.84 years. The most common risk factors for S. maltophilia keratitis were trauma (6/16, 37.5%), use of contact lenses (6/16, 37.5%), and herpes simplex virus keratitis (3/16, 18.8%), which caused ocular instability. Regarding the antibiotic sensitivities, most isolates (15/16, 93.8%) were susceptible to fluoroquinolones, 87.5% (14/16) of them to aminoglycosides, and 81.3% (13/16) of them to beta-lactams. Patients were classified into two groups according to the initial antibiotic eye drops, and there were significant differences in the final visual acuity between two groups: mixed fluoroquinolone, beta-lactam, aminoglycoside group, and mixed beta-lactam and aminoglycoside groups (p = 0.039).

Conclusion

Ocular infection due to S. maltophilia is an opportunistic infection followed by instability of the ocular surface. In cases of S. maltophilia infection, mixed use of fluoroquinolone, beta-lactam, and aminoglycoside should be considered for treatment of choice.

Successful Control of a Co-Infection Caused by Candida albicans and Pseudomonas aeruginosa in Keratitis

Nowadays, the co-infection of different classes of pathogens is a major concern. The objective of this study was to develop a successful therapy for keratitis caused by the co-infection of Candida sp. with Pseudomonas sp, which is difficult to cure. The study is based on a 47 years old male farmer showing redness and watering in the right eye for 15-days. ; Methods: The microbiological examination was performed to isolate the causative organisms, i.e. Pseudomonas aeruginosa and Candida albicans. They were cultured separately along with their co-culture and treated with ciprofloxacin and amphotericin B during the growing stage to predict a definite cure. ; Results: Scanning electron microscope (SEM) results confirmed the inter-specific interaction between the two different types of microorganisms. Amphotericin-B and Ciprofloxacin showed the least MIC value for both organisms in co-culture. ; Conclusion: Treatment with Amphotericin-B and 5% ciprofloxacin effectively hindered the growth of Pseudomonas aeruginosa and Candida albicans, the co-infection of which caused keratitis. This therapy may be successfully implied for such cases of co-infection in the future.

Clinical Features, Antibiotic Susceptibility Profile, and Outcomes of Infectious Keratitis Caused by Stenotrophomonas maltophilia

PURPOSE

Stenotrophomonas maltophilia, an uncommon cause of infectious keratitis, is difficult to treat because of its resistance to multiple antibiotics. The purpose of this study is to describe the clinical features, antibiotic susceptibility profile, and outcomes of S. maltophilia keratitis.

METHODS

A retrospective review of records from 1987 to 2016 identified 26 eyes of 26 patients who were treated at the Bascom Palmer Eye Institute for an S. maltophilia corneal ulcer. Clinical data were analyzed as to predisposing factors, clinical presentation, antibiotic susceptibility, treatment selection, and clinical outcomes.

RESULTS

Median age at presentation was 65 years (range, 16-98). Twelve patients were using topical corticosteroids, 8 patients had a history of penetrating keratoplasty, and 9 were contact lens wearers. All patients received topical antibiotics, 2 required therapeutic penetrating keratoplasty, and 1 was enucleated. At presentation, 57.7% (15/26) of the patients had visual acuity of 20/400 or worse. At the final visit, only 30.4% (7/23) of the patients had visual acuity worse than 20/400, whereas 65.2% (15/23) of the patients had 20/100 or better. Almost all isolates (25/26, 96.2%) were susceptible to fluoroquinolones and 77.3% (17/22) of them to polymyxin B/trimethoprim. Only 33.3% (5/15) of the tested isolates were susceptible to aminoglycosides and 58.3% (7/12) to cephalosporins.

CONCLUSIONS

Infectious keratitis due to S. maltophilia presents a treatment challenge because of its resistance to aminoglycosides and cephalosporins, which are typically used for empiric broad-spectrum gram-negative coverage as fortified solutions. Fluoroquinolones and polymyxin B/trimethoprim should be considered instead in cases of S. maltophilia infection.

Clinical Characteristics of Stenotrophomonas maltophilia Keratitis

PURPOSE

Stenotrophomonas maltophilia is an important opportunistic pathogen but an uncommon cause of corneal infections. This study aimed to report the clinical features, antibiotic susceptibility, treatments, and visual outcomes of S. maltophilia keratitis.

METHODS

The medical records of 21 patients with culture-proven S. maltophilia-associated infectious keratitis in our hospital between January 1, 2003, and December 31, 2014, were retrospectively reviewed. The clinical features of patients with S. maltophilia keratitis were compared with those of patients from 17 previously reported cases.

RESULTS

The most common risk factors for S. maltophilia keratitis were preexisting corneal disease or previous corneal surgery (16), followed by soft contact lens wear (9). Nine patients (42.9%) were multifactorial. Polymicrobial infections was detected in 12 eyes (57.1%). All S. maltophilia isolates were susceptible to levofloxacin and moxifloxacin. A total of 17 of 21 patients (81.0%) had favorable responses to topical antimicrobial treatment, and 10 (47.6%) required surgical intervention for promotion of reepithelialization (6) and corneal perforation (4). Final vision ranged from light perception to 20/20. The clinical features of S. maltophilia keratitis in our cases and in previously reported cases were similar.

CONCLUSIONS

S. maltophilia keratitis primarily affects patients with compromised ocular surfaces. S. maltophilia demonstrates in vitro susceptibility and a strong clinical response to fluoroquinolones.

Stenotrophomonas maltophilia endophthalmitis following cataract surgery: clinical and microbiological results

Background

Stenotrophomonas maltophilia is a Gram-negative organism known to cause opportunistic infections. It is a rare source of endophthalmitis, often in the setting of trauma, but has been reported following cataract extraction. The purpose of this study was to evaluate antimicrobial sensitivities, clinical characteristics, and treatment outcomes in patients with endophthalmitis caused by S. maltophilia following cataract extraction.

Methods

A retrospective case review of records from January 1, 1990 to June 30, 2010 was performed at the Bascom Palmer Eye Institute.

Results

Eight cases of S. maltophilia endophthalmitis were identified following cataract surgery. Initial visual acuity ranged from 20/200 to light perception. Time to diagnosis with cultures was 2–118 days. Patients received either intravitreal tap and inject (n = 5) or pars plana vitrectomy with intravitreal antibiotic injections (n = 3). All patients had vitreous or anterior chamber cultures positive for S. maltophilia. Seven of seven isolates tested were found to be sensitive to ceftazidime. Seven of eight isolates were sensitive to polymyxin B, six of eight isolates were sensitive to amikacin, and five of the seven isolates tested were sensitive to ciprofloxacin. Two of four tested isolates were sensitive to trimethoprim-sulbactam. All eight isolates were resistant to gentamicin and seven of the seven tested isolates were resistant to imipenem. All patients received intravitreal ceftazidime as part of the initial treatment regimen. Final visual acuity ranged from 20/25 to 4/200.

Conclusion

S. maltophilia endophthalmitis is a rare source of endophthalmitis following cataract surgery. A case series of eight independent patients is reported, along with antibiotic resistance profiles and clinical outcomes. Isolates showed sensitivity to ceftazidime, amikacin, and polymyxin, with variable sensitivity to other antibiotics, therefore differing from previous reports.

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.

Late-onset intrascleral dissemination of Stenotrophomonas maltophilia scleritis after pterygium excision

PURPOSE

To report a case of pterygium excision-related infectious scleritis with late-onset intrascleral dissemination.

METHODS

Case report.

RESULTS

A 72-year-old female patient was referred for Stenotrophomonas maltophilia scleritis after undergoing pterygium excision 18 years earlier. Surgical debridement and a tectonic corneal patch graft, along with conjunctival flap, were performed to repair the scleral defect after treatment with fortified topical and systemic antibiotics. However, intrascleral dissemination of scleritis occurred 5 months after the initial episode.

CONCLUSIONS

Intrascleral dissemination of S. maltophilia scleritis after pterygium excision might be delayed because of limited invasiveness and inherent resistance to several antibiotics. Long-term follow-up may be needed to protect against the possibility of late-onset intrascleral dissemination.

Clinical aspects and prognosis of mixed microbial (bacterial and fungal) keratitis

PURPOSE

To investigate the predisposing factors, clinical presentations, treatment results, and prognosis of keratitis caused by mixed infectious agents (bacteria and fungi).

METHODS

This is a retrospective study of cases with mixed bacterial and fungal keratitis, presented between January 2000 and December 2007 at a tertiary referral hospital. The study was performed to identify and analyze its risk factors, causative microbial organisms, clinical features, and therapeutic outcomes.

RESULTS

Thirty-three cases of mixed bacterial and fungal keratitis in 33 patients were identified. Twenty-one cases (64%) were men, and the mean age was 64.3 ± 10.3 years. The average follow-up time was 7.2 ± 6.6 months. The most common predisposing factor for mixed keratitis was a history of ocular trauma (46%), followed by ocular surface diseases (27%). The mean pretreatment infiltration size was 11.7 ± 12.7 mm. The most common causative organisms were Staphylococcus epidermidis and Fusarium species. Seventeen cases (52%) underwent various surgical interventions: evisceration in 7 eyes (21%), penetrating keratoplasty in 5 eyes (15%), amniotic membrane transplantation in 5 eyes (15%), and so on. Seventeen cases (52%) were included in the initial treatment failure group. The significant risk factor for initial treatment failure was a large ulcer size (size over 15 mm) (P = 0.031).

CONCLUSIONS

The most common risk factor for mixed bacterial and fungal keratitis was ocular trauma, and the most common combination was Staphylococcus epidermidis and Fusarium species. Usually, patients with mixed bacterial and fungal keratitis have poor prognosis. Thus, when the infectious keratitis is running an atypical course or found unresponsive to the initial medical treatment, the possibility of a mixed infection by bacterial and fungal organisms should be considered.