Topical Amikacin Research Articles

Atypical mycobacterial keratitis: Clinical outcome in nonrefractive surgery cases.

To identify the predisposing factors, clinico-microbiological profiles, and treatment responses in patients with atypical mycobacterial keratitis. The study retrospectively analyzed patients who presented at a tertiary eyecare center in eastern India with atypical mycobacterial keratitis between 2008 and 2021. The diagnostic criteria included cases positive for acid-fast bacilli on Ziehl-Nielsen stain or culture. The antibiotic susceptibility pattern was observed, and treatment was initiated accordingly. Out of the 29 cases, ocular predisposing factors were present in 62.1% with an antecedent history of trauma, and vegetative matter was the most common risk factor. There was no predisposing association with systemic conditions in any case. A long lag time was observed between the onset of corneal infection and presentation in 79.3% of cases, with the average time being 43.7 days. Clinical signs mimicked fungal keratitis in most cases. Typical cracked windshield appearance was only observed in two cases. Two patients presented with clinical pictures like peripheral ulcerative keratitis. Topical amikacin was used as treatment in 28 cases. Based on disk diffusion assay, 28 (96.5%) isolates were sensitive to amikacin. Twelve (41.3%) were sensitive to vancomycin, six (20.6%) to gatifloxacin, six (20.6%) to ciprofloxacin, and four (13.7%) to moxifloxacin. Twelve participants showed good final visual acuity posttreatment, which improved to over two lines of Snellen's visual acuity chart (44.5%). Atypical mycobacteria keratitis may not present with classically described clinical features. The duration of presentation, clinical presentation, special microbiological stains, targeted therapy, and antibiotic susceptibility patterns are the key to successfully managing these intractable infections and obtaining favorable outcomes.

Mycobacterium abscessus Corneal Ulcer with Conjunctival Toxicity due to Topical Amikacin

Purpose: This report presents a case of repeated toxic conjunctival necrosis caused by amikacin eye drops in a patient with a corneal ulcer induced by Mycobacterium abscessus (M. abscessus).Case summary: During treatment for herpetic keratitis with complaints of conjunctival hyperemia and eye pain in the right eye for 1 month. Slit-lamp microscopy revealed a circular corneal epithelial defect and stromal infiltration of her right eye. Gram staining and culture were performed, and eye drops were prescribed for empirical treatment. The bacterial culture grew M. abscessus. Antibiotic susceptibility tests showed resistance to quinolone. The patient was prescribed amikacin eye drops and the corneal epithelial defects improved. Two weeks later, circular conjunctival epithelial defects and hyperemia were observed on the inferior conjunctiva. Conjunctival necrosis caused by amikacin was suspected. The amikacin eye drops were discontinued and the conjunctival lesion improved. However, the patient’s corneal ulcer recurred. The amikacin eye drops were restarted, but conjunctival toxicity recurred, so she was treated with topical clarithromycin and moxifloxacin. The eye drops were gradually reduced and the lesion healed leaving mild corneal opacity.Conclusions: M. abscessus-induced keratitis resistant to quinolone antibiotics requires long-term combined therapy with multiple drugs. Amikacin eye drops should be used carefully as conjunctival toxicity may occur.

Citrobacter keratitis: predisposing factors and clinical characteristics

PurposeTo report predisposing factors, clinical presentation, antibiotic sensitivity, and management of Citrobacter-caused infectious keratitis.MethodsWe retrospectively reviewed the medical records of culture-proven cases of Citrobacter keratitis in a tertiary referral center for 8 years (from January 2012 to September 2020). Demographic data of the patients, predisposing factors, and presenting signs were extracted.ResultsEighteen cases of microbial keratitis due to Citrobacter spp. were identified. The median age of the patients was 66 years (range: 10–89, interquartile range : 59–81). Thirteen patients were male and 5 were female. Multiple predisposing factors were identified in all eyes, including ocular surface disease (n = 8), previous corneal surgery (n = 6), and history of ocular trauma (n = 6). Five patients were diabetic. Corrected distance visual acuity (CDVA) of patients was light perception (LP) in 8 patients, hand motion (HM) in 7, counting fingers (CF) at 1 m in 1, and CF at 2 m in 2 patients. Thirteen eyes exhibited hypopyon. An area of corneal thinning was observed in 7 eyes (38.9%). Endophthalmitis due to infectious keratitis developed in one patient. In vitro susceptibility testing confirmed high sensitivity to ceftazidime and aminoglycosides. Medical management consisted primarily of topical amikacin (20 mg/ml) combined with topical cefazoline (50 mg/ml) (72.2%). Surgical tectonic procedures were carried out in 7 eyes (38.9%).ConclusionCitrobacter spp. is a rare cause of bacterial keratitis.Previous keratoplasty and ocular surface problems are important risk factors. The prognosis is not good and surgical tectonic intervention is required in many cases to resolve the corneal infection.

Outcomes of Nontuberculous Mycobacterial Keratitis After Clear Corneal Incision Phacoemulsification Surgery: A Case Series of 6 Eyes in South Florida.

The purpose of this study was to present the successful management and outcomes in a series of 6 cases of culture-positive nontuberculous mycobacterial keratitis after clear corneal incision phacoemulsification surgery. This is a case series of 6 consecutive eyes that presented at the Cornea Division at an academic institution, diagnosed with culture-positive nontuberculous mycobacterial keratitis after phacoemulsification surgery. Six eyes of 5 patients were included. The mean interval from cataract surgery to presentation was 7.7 weeks. All cases presented with intrastromal abscesses adjacent to corneal incisions, and 2 had scleral extension of the infection. Isolated organisms were Mycobacterium abscessus (n = 4), Mycobacterium chelonae (n = 1), and Mycobacterium mucogenicum (n = 1). All cases were treated with topical amikacin 8 mg/mL for 10.5 weeks on average. All cases received either oral clarithromycin at 500 mg twice-daily dosage or oral azithromycin at 500 mg daily. Two patients with scleral abscesses underwent surgical debridement with amniotic membrane grafts. All 6 eyes achieved infection resolution and good visual recovery, with the final visual acuity ranging from 20/20 to 20/60. None of the patients experienced recurrence of infection. Prompt medical treatment with combined topical and oral therapy can lead to infection resolution and favorable visual recovery. Early surgical intervention can ensure good outcomes in cases of scleral extension.

Microbial keratitis due to infection with Citrobacter freundii

We report a unique case of Citrobacter freundii keratitis in a 35-year-old male presented with a paracentral corneal ulcer secondary to injury with a tile particle. Clinically, it seemed like a fungal ulcer. However, the bacterial culture was positive for Citrobacter freundii, which responded to topical amikacin and ceftazidime. Citrobacter freundii is a facultative anaerobic gram-negative bacterium belonging to the family of Enterobacteriaceae being associated with external eye infections; while this is another report of it being associated with microbial keratitis.

An unusual case of Mycobacterium chelonae in contact lens solution

Importance: Microbial keratitis is an increasing complication amongst contact lens wearers. In the absence of positive cultures, there should be a high index of suspicion for uncommon pathogens including acanthamoeba, herpes simplex, fungi and mycobacteria. Our unique case highlights mycobacteria as serious a pathogen which requires aggressive therapy. Successful treatment of mycobacteria could result in good visual potential. Observations: We describe an original case of presumed Mycobacterium chelonae infection and management in an elderly contact lens wearer with a protracted clinical course of bilateral non-healing epithelial defects. The patient initially did not reveal she was a contact lens wearer. She later confessed to washing contact lens with domestic tap water, but later changed this practice by using a contact lens disinfecting solution. Inspection of her contact lens solution revealed expiry 3 years earlier, from which Mycobacterium chelonae was eventually isolated. Resolution of her keratitis only occured after triple antibiotic therapy of topical amikacin, moxifloxacin and azithromycin supported by oral clarithromycin. She later underwent penetrating keratoplasty in both eyes, with good visual outcome. Conclusions and relevance: To the best of our knowledge, this is the first reported case of bilateral Mycobacterium chelonae keratitis arising from contaminated CL solution. This case illustrates the importance of considering Mycobacterium in the differential diagnoses when treating non healing keratitis. It is important to enquire about contact lens wear and hygiene in all keratitis cases, regardless of patient age. There is a need to create public awareness regarding the potential serious risk of CL wear and safe CL practice that includes monitoring by eye care professionals.

Contact Lens-associated Nocardial Necrotizing Scleritis

A 52 year-old, contact lens-wearing man presented with progressive right eye pain and redness for one month. He had been evaluated and treated for necrotizing scleritis by multiple eye care specialists prior to presentation. He underwent a complete systemic work-up for both autoimmune and infectious causes of scleritis, including a culture. The culture revealed heavy growth of Nocardia asteroides complexes. The patient was treated with topical amikacin and oral Bactrim. Following several weeks of antibiotic treatment, the patient's infection resolved completely, and his visual acuity returned to baseline status. Nocardia is a rare but potentially devastating cause of necrotizing scleritis that may affect contact lens wearers without an associated keratitis. Prompt recognition and early treatment with appropriate antimicrobial agents are critical to achieve a favorable outcome.

Nocardia transvalensis keratitis: an emerging pathology among travelers returning from Asia

BackgroundThe incidence rate of Nocardia keratitis is increasing, with new species identified thanks to molecular methods. We herein report a case of Nocardia transvalensis keratitis, illustrating this emerging pathology among travellers returning from Asia.Case presentationA 23-year-old man presented with a 10-week history of ocular pain, redness, and blurred vision in his right eye following a projectile foreign body impacting the cornea while motor biking in Thaïland. At presentation, a central epithelial defect with a central whitish stromal infiltrate associated with pinhead satellite infiltrates was observed. Identification with 16S rRNA PCR sequencing and microbiological culture of corneal scraping and revealed N. transvalensis as the causative organism. Treatment was initiated with intensive topical amikacin, oral ketoconazole and oral doxycycline. After a four-week treatment period, the corneal infiltrate decreased so that only a faint subepithelial opacity remained.ConclusionNocardia organisms should be suspected as the causative agent of any case of keratitis in travelers returning from Asia. With appropriate therapy, Nocardia keratitis resolves, resulting in good visual outcome.

Infectious Scleritis after Subtenon Triamcinolone Acetonide Injection

Purpose: To report a case of Staphylococcus epidermidis infection after subtenon injection (STI) of triamcinolone acetonide (TA). Design: Interventional case report.Methods: A 20-year-old patient with corneal graft rejection received STI of TA after insufficient response to topical and oral corticosteroids.Results: After conjunctival necrosis, necrotizing scleritis progressed although topical and systemic steroids were discontinued. Systemic ciprofloxacin, topical fortified amikacin, and vancomycine drops were used. Complete recovery was obtained after 3 weeks. Smears and cultures showed Staphylococcus epidermidis infection.Conclusions: Although uncommon, infectious scleritis can occur following uncomplicated subconjunctival corticosteroid injections. Infectious scleritis can be very difficult to diagnose as it may mimic an immune mediated disease. If the conjunctiva is suspected to be involved, a smear should always be taken. Prevention by sterilizing the injection site (prep and drape) and strong antibiotic prophylaxis are recommended to reduce the risk of the infectious scleritis.

Infectious keratitis outbreak after laser in situ keratomileusis at a single laser center in Japan

To evaluate an outbreak of infectious keratitis after laser in situ keratomileusis (LASIK) at a single laser center in Japan. Tokyo Dental College, Chiba, Japan. Case series. Relevant demographic and clinical data were obtained from case records using a standardized multicenter questionnaire at 12 major hospitals. The clinical manifestations, management, and outcomes were analyzed. Thirty-nine eyes of 30 patients developed infectious keratitis after LASIK at the specified clinic. Cases of infection continued to appear over a 5-month period. The most common interval between LASIK and the onset of infection was within 2 weeks (36 eyes, 92.3%). Slitlamp manifestation included granular opacity beneath flap (71.8%), multiple infiltration (66.7%), and epithelial defect (30.8%). Mycobacterium was identified as the causative organism in 9 eyes (23.1%). In most cases, topical amikacin, arbekacin, and erythromycin in addition to fourth-generation fluoroquinolones were effective. Flap amputation was necessary in 10 eyes (25.6%) of 10 patients. Decimal visual acuity at initial presentation was worse than 0.10 in 14 eyes (35.9%), 0.15 to 0.50 in 8 eyes (20.5%), and 0.60 to 0.90 in 7 eyes (17.9%) and was better than 1.00 in 10 eyes (25.6%). Final decimal visual acuity was worse than 0.10 in 2 eyes (5.1%), 0.15 to 0.50 in 5 eyes (12.8%), and 0.60 to 0.90 in 11 eyes (28.2%) and was better than 1.00 in 21 eyes (53.8%). Mycobacterium was identified as the causative organism of this outbreak. This study shows the possibility of an epidemic of post-LASIK infectious keratitis.

Effects of Photodynamic Therapy on Rapidly Growing Nontuberculous Mycobacteria Keratitis

The authors investigated the antimicrobial effect of methylene blue (MB)-mediated photodynamic therapy (PDT) on Mycobacterium fortuitum keratitis. In the in vitro study, the mycobacterial suspension and colonies were treated with the following: no MB, no light (normal control); MB and no light (dye control); light and no MB (light control); MB and light (PDT). Morphologic characteristics were examined by transmission electron microscopy. The bactericidal effects of combined PDT and antibiotic therapy (ciprofloxacin, moxifloxacin, and amikacin) were determined using the broth microdilution technique. Twenty-one rabbits with Mycobacterium keratitis were randomly divided into three groups (no treatment, topical amikacin treatment, and PDT combined with amikacin treatment). The clinical features of keratitis were scored and graded before treatment and before euthanatization. The diseased corneas were trephined for quantitative bacteriologic analysis to determine the antibacterial efficacy of the treatment. In the in vitro tests, the bacterial count had a 2-log reduction immediately after PDT treatment at 100 J/cm(2) with 10(-3)% MB. After PDT at 100 J/cm(2) with 10(-2)% MB, almost no viable bacteria were detected. PDT had a synergistic antimicrobial effect in combination with antibiotics. The phototoxicity occurred in the cytoplasm first and then disrupted the mycobacterial cell walls by lysis. In the rabbit keratitis model, combined PDT resulted in significantly less bacterial burden (P < 0.01) than in the amikacin group. This study demonstrated the effectiveness of MB-mediated PDT against Mycobacterium fortuitum. PDT could be a potential alternative treatment for nontuberculous mycobacterial corneal infections.

Keratitis after Implantation of Intrastromal Corneal Ring Segments (Intacs) Aided by Femtosecond Laser for Keratoconus Correction: Case Report and Description of the Literature

The majority of reported cases of infectious keratitis after intrastromal corneal ring segment implantation have been described after mechanical implantation of the segments. We present a case of keratitis after implantation of intrastromal corneal ring segments (Intacs) aided by femtosecond laser for keratoconus correction and review the relevant literature. A 31-year-old woman with keratoconus underwent uneventful sequential implantation of intrastromal corneal ring segments (Intacs) aided by femtosecond laser performed 6 weeks apart. Two months after surgery in the second eye, she complained of red eye, pain, and decreased vision of 2 days' duration. Left eye visual acuity was 20/100. Slit-lamp examination of the left eye revealed a stromal infiltrate at the lower segment near the incision site. The infiltrate progressed despite topical treatment of vancomycin and ceftazidime. Cultures were negative. The inferior segment was removed and the inferior channel irrigated with antibiotics. One day later significant fibrin and 1-mm hypopyon were detected in the anterior chamber Significant improvement was observed after adding topical amikacin and amphotericin B. Six months later, a small stromal scar is present at the inferior incision site and best-corrected visual acuity is 20/25. To our knowledge, this is the second reported case of keratitis after implantation of intrastromal corneal ring segments (Intacs) aided by femtosecond laser for keratoconus correction. Prompt and adequate treatment is essential to prevent irreversible reduction of visual acuity.

Oral moxifloxacin and topical amikacin for Mycobacterium abscessus keratitis after laser in situ keratomileusis

We report a case of Mycobacterium abscessus keratitis after elective laser in situ keratomileusis in a 19-year-old woman. The infection started 3 weeks after uneventful surgery, and the patient received multiple antimicrobial treatments without response. A corneal scrape isolate showed an acid-fast bacterium that was subsequently confirmed by culture to be M abscessus. Prompt treatment of oral moxifloxacin 400 mg twice daily and hourly topical amikacin 2.5% was started. Recovery occurred within the first week of treatment, with complete resolution 3 weeks after presentation. The final uncorrected distance visual acuity was 6/9. We comment on other reports of post-LASIK keratitis caused by M abscessus, the in vitro sensitivity to antibiotic agents described in the literature, and the use of oral moxifloxacin as a potential good alternative treatment based on its good ocular bioavailability, which in our case allowed resolution without the need for surgical intervention.

In Vitro Antibiotic Susceptibility of Rapidly Growing Nontuberculous Mycobacteria Isolated from Patients with Microbial Keratitis

Purpose: This study was undertaken to determine the antibiotic susceptibility and minimum inhibitory concentrations (MIC) of amikacin, tobramycin, ciprofloxacin, gatifloxacin, azithromycin, and clarithromycin against rapidly growing nontuberculous mycobacteria isolated from patients with keratitis.Methods: A total of 15 rapidly growing nontuberculous mycobacteria isolated from corneal scrapings of keratitis patients from January 1999 through December 2007 were subjected to antimicrobial susceptibility testing by the E-Test to amikacin, tobramycin, ciprofloxacin, gatifloxacin, azithromycin, and clarithromycin.Results: Out of 15 isolates, 13 were identified as Mycobacterium chelonae complex and 2 as Mycobacterium fortuitum complex. Based on minimum inhibitory concentration (MIC) cut off, all 15 (100%) isolates were sensitive to amikacin, azithromycin, and clarithromycin, 13 (86%) were sensitive to tobramycin, nine (60%) to gatifloxacin, and only 6 (40%) to ciprofloxacin. The MIC range was 0.25–4 µg/ml for amikacin, 0.5–1 µg/ml for azithromycin, 0.125–1 µg/ml for clarithromycin, 0.5–16 µg/ml for ciprofloxacin, and 0.25–16 µg/ml for tobramycin. MIC90 for amikacin was 2 µg/ml, azithromycin 1 µg/ml, clarithromycin 0.75 µg/ml, ciprofloxacin 8 µg/ml, gatifloxacin 8 µg/ml, and for tobramycin it was 4 µg/ml.Conclusions: All the isolates were sensitive to amikacin, azithromycin, and clarithromycin, but the MIC values of clarithromycin and azithromycin were lower than amikacin. Based on in vitro susceptibility results it appears that the topical amikacin in combination with oral clarithromycin or azithromycin is the best treatment option for rapidly growing nontuberculous mycobacterial keratitis.

A case of amniotic membrane transplantation in non-healing Nocardia asteroides keratitis

A patient with severe non-healing microscopically proven Nocardia keratitis was treated with maximal topical amikacin followed by amniotic membrane transplantation (AMT) 2 months later (single-layer epithelial side-down). Epithelial healing was achieved, but neovascularization continued. This case report indicates that AMT combined with topical antibiotic provides pain relief and allows epithelial healing in severe Nocardia keratitis.

Outbreak of Nocardia keratitis after photorefractive keratectomy : Clinical, microbiological, histopathological, and confocal scan study

Nocardia keratitis occurred in 4 eyes of 3 patients (2 women and 1 man) who had photorefractive keratectomy (PRK) by the same surgeon at the same center. Two eyes of the first 2 patients required lamellar keratectomy to debulk the involved stroma and obtain specimens for microbiological and histopathological evaluation. Light microscopic examination disclosed gram-positive and acid-fast filaments of Nocardia that were confirmed by the microbiological results. Diagnosis of Nocardia keratitis in the third case was not as challenging as in the first 2 cases because of a high index of suspicion. Confocal scans of all cases disclosed hyperreflective and slender, fibril-like structures in the corneal stroma. All eyes responded favorably to topical amikacin and the infection resolved without recurrence. The most probable cause of the outbreak was inadequate attention to sterility during surgery.

Nocardia transvalensis Resistant to Amikacin: An Unusual Cause of Microbial Keratitis

To report a case of microbial keratitis caused by Nocardia transvalensis with resistance to amikacin. Case report. A 51-year-old man was referred with a 10-week history of ocular pain, photophobia, redness, and blurred vision. At his initial presentation, a corneal foreign body was removed and he was diagnosed with anterior uveitis, with commencement of topical corticosteroid therapy and ofloxacin. Despite treatment, he experienced ongoing foreign body sensation and glare. At presentation to our clinic, a central epithelial defect with multiple stromal infiltrates in a wreath pattern was identified and a diagnosis of infective keratitis was made. He was initially commenced on topical amikacin, oral trimethoprim-sulfamethoxazole, and oral voriconazole. Corneal scraping confirmed Nocardia species. Microbiological culture revealed N. transvalensis as the causative organism, with resistance to several antibiotics, including amikacin. Clinically, there was only partial response of the keratitis to initial therapy. Treatment was changed to oral trimethoprim-sulfamethoxazole and topical ciprofloxacin, with eventual clinical improvement. This is the first reported case of N. transvalensis keratitis. In patients with Nocardia keratitis and only partial response to amikacin treatment, this isolate should be considered as it is resistant to aminoglycoside antibiotics.

Fourth-generation fluoroquinolone-resistant mycobacterial keratitis after laser in situ keratomileusis

We report a case of mycobacterial keratitis resistant to fourth-generation fluoroquinolones after laser in situ keratomileusis (LASIK) with fourth-generation fluoroquinolone prophylaxis. While receiving moxifloxacin post LASIK, the patient was diagnosed with moxifloxacin-resistant Mycobacterium chelonae keratitis. Culture susceptibilities revealed isolates resistant to moxifloxacin and gatifloxacin, and treatment with topical amikacin and clarithromycin with oral doxycycline and clarithromycin along with flap amputation was necessary to control the infection. This case demonstrates the potential limitations in the coverage of these antibiotic agents.

Necrotizing nocardial scleritis after combined penetrating keratoplasty and phacoemulsification with intraocular lens implantation: a case report and review of the literature

We report the history and clinical presentation of an 88-year-old female with Fuchs dystrophy who developed an acute anterior necrotizing scleritis in her left eye 23 months after an uncomplicated combined penetrating keratoplasty and phacoemulsification with intraocular lens implantation which progressed to slceral perforation with uveal prolapses. The patient underwent a complete systemic work-up for both autoimmune and infectious causes of scleritis. Surgical specimens of the area of scleral perforation were sent for histology and microbiologic studies. Analysis of surgical specimens revealed the presence of culture-proven Nocardia asteroides as a causative agent for the patient's scleral perforation. Results of her systemic autoimmune work-up were not conclusive. Successful treatment with tectonic scleral reinforcement with donor corneal tissue and preserved pericardium, oral and topical trimethoprim-sulfamethoxazole and topical amikacin salvaged the globe and increased vision. The patient's final best-corrected visual acuity sixteen months after her last operation remains 20/70. Prompt surgical intervention with submission of appropriate specimens for pathological diagnosis and microbiology, along with consultation with rheumatologic and infectious disease specialists, are mandatory to minimize visual loss in cases of suspected infectious necrotizing scleritis.

Recalcitrant Post-LASIK Mycobacterium chelonae Keratitis Eradicated after the Use of Fourth-Generation Fluoroquinolone

To report a patient with Mycobacterium chelonae keratitis after LASIK and discuss therapeutic measures. Interventional case report and literature review. A healthy, 25-year-old man presented 6 weeks after LASIK with infectious keratitis in the left eye. Scrapings were obtained from the central stromal bed after lifting the flap and inoculated on culture media. Response to medical treatment. Mycobacterium chelonae was identified from stromal bed scrapings. The protracted course of the infection necessitated surgical debridement and flap amputation with slow and suboptimal response to prolonged (14 weeks) treatment with topical amikacin 3.3%, clarithromycin 1%, and levofloxacin 0.5%. The substitution of levofloxacin 0.5% with gatifloxacin 0.3% resulted in closure of the epithelial defect within 1 week and resolution of the infiltrates in 3 weeks. The combined regimen of gatifloxacin 0.3%, amikacin 3.3%, and clarithromycin 1% was continued for a total of 4 months. The patient remains infection free 1 year after stopping all antibiotics. Treatment of post-LASIK nontuberculous mycobacteria remains a challenge. Institution of combination therapy including fortified amikacin, clarithromycin 1%, and a fourth-generation fluoroquinolone appeared to be beneficial in this patient.