Fortified Amikacin Research Articles

MYCOBACTERIUM ABSCESSUS SCLERAL BUCKLE INFECTION.

To report the successful management of a rare case of Mycobacterium abscessus scleral buckle infection. Case report. A 63-year-old woman with a history of sarcoid anterior uveitis and macula-off retinal detachment repaired by scleral buckle and pars plana vitrectomy presented with eye pain, redness, and purulent drainage in the left eye. Slit-lamp examination showed superonasal scleral buckle exposure, purulent conjunctival discharge, corneal edema, nongranulomatous keratic precipitates, and anterior chamber cell and flare. The patient underwent urgent scleral buckle removal. Intraoperatively, an area of scleral thinning without perforation underneath the exposed buckle was discovered and covered with a scleral patch graft, and an amniotic membrane graft was used to cover an area of bare sclera with significant conjunctival scarring and retraction. Cultures grew M. abscessus panresistant except to amikacin. After 6 weeks of fortified amikacin drops and a long taper of topical steroid therapy for persistent postoperative anterior uveitis, the patient's symptoms resolved. Mycobacterium is an emerging causative agent of scleral buckle infections. Our report provides insights about the management of such cases.

Nocardia keratitis following corneal cross linking for keratoconus

We report a case of Nocardia keratitis following corneal cross-linking for progressive keratoconus. A 26-year-old otherwise healthy woman underwent crosslinking for keratoconus in her left eye. She presented with corneal infiltrates with a wreath-like pattern, on the seventh postoperative day. Gram's and acid-fast staining revealed Nocardia. She was managed with topical fortified amikacin 2.5% eye drops. The keratitis resolved to leave dense vascularization which was managed with topical prednisolone 1% eye drops.

Acute interface infectious keratitis with multidrug resistant Klebsiella and Escherichia Coli following deep anterior lamellar keratoplasty

Acute interface infectious keratitis (AIIK) is a rare and devastating complication following lamellar keratoplasty. Here, we report a case of AIIK following deep anterior lamellar keratoplasty (DALK) caused by double gram-negative bacilli and required urgent therapeutic penetrating keratoplasty (TPK). Microbiology revealed co-infection with Klebsiella and E. Coli sensitive only to colistin. Donor rim culture also grew Klebsiella. TPK was successful in controlling the infection and the patient responded to topical fortified amikacin and ciprofloxacin. Since optical quality tissue was used, the patient regained 20/40 vision postoperatively. This report highlights that immediate TPK and intense antimicrobial therapy can salvage these eyes with good visual outcome.

An Unusual Case of Nonhealing Granulomatous Keratitis Caused by Mycobacterium chelonae in a Healthy Middle Aged Adult.

Purpose. To report a rare presentation of culture positive Mycobacterium chelonae (M. chelonae) corneal ulcer and its management. Case Report. We report a rare case with history of chronic pain and blurriness of vision. Examination revealed chronic nonhealing paracentral corneal ulcer inferiorly at 5 to 7 o'clock meridian with anterior chamber cells 1+ unresponsive to routine antibiotic and antifungal medications with Mantoux test (MT) positivity in a middle aged nondiabetic patient with no prior obvious history of trauma, ocular surgery, and contact lens usage. Discussion. Ziehl Neelsen (ZN) staining in nonhealing ulcer revealed acid fast bacilli typical of M. chelonae with subsequent culture positivity in Lowenstein Jensen (LJ) medium. Subsequent treatment with topical fortified amikacin and tobramycin resulted in rapid healing of corneal ulcer. Conclusion. M. chelonae presenting as a chronic nonhealing corneal ulcer spontaneously occurring in a healthy young adult with no predisposing factor draws the need to have a good index of suspicion by performing ZN stain and culture and its subsequent successful management with topical fortified amikacin and tobramycin.

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.

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.

Treatment and outcome of nocardia keratitis.

To report our experience in treatment and outcome ofNocardia keratitis. Medical and microbiology records of seven cases of culture-provenNocardia keratitis seen between January 1997 and March 1999 were reviewed retrospectively. In all patients, corneal scrapings were obtained for direct microscopic evaluation and culture. Drug sensitivity was determined by the Kirby-Bauer disk-diffusion method. The minimum inhibitory concentration of ciprofloxacin and amikacin for these isolates was determined by agar dilution method. Response to medical therapy and the end result were analyzed. By the in vitro Kirby-Bauer disk-diffusion techniques, all isolates were sensitive to amikacin; six of these isolates were sensitive to gentamicin and four were sensitive to ciprofloxacin. The minimum inhibitory concentration (MIC) of amikacin for all isolates by the agar-dilution technique was well below the MIC breakpoint forNocardia resistance, whereas the MIC of ciprofloxacin was above the MIC breakpoint forNocardia resistance. All patients responded to medical therapy. The corneal infection resolved in three patients after treatment with ciprofloxacin, in one patient after fortified gentamicin, and in three patients after fortified amikacin. Outcome details were available for six patients. There was good visual recovery in four patients, with visual acuity of 20/25 or better in three. The cornea of two patients developed nonvascularized scars, and in four patients in whom the infiltrates were peripheral, vascularization was seen. Although patients ofNocardia keratitis may respond to other antibiotics, amikacin appears to be a drug of choice. In this small series, when appropriate therapy was initiated,Nocardia keratitis resolved promptly with good visual recovery.

Penetration of Amikacin into Aqueous Humor of Rabbits

Amikacin is an aminoglycoside antibiotic that has poor corneal penetration due to its hydrophilic properties. The purpose of this study was to compare and evaluate the penetration of amikacin sulfate into aqueous humor of the rabbit eye when applied by different routes and concentrations, namely 100 or 250 mg/ml topical fortified amikacin eye drops, 100 or 250 mg/ml amikacin-embedded soft contact lenses and 25 mg subconjunctival amikacin injection. One hour after application, amikacin was not detectable in any of the 100 mg/ml concentration groups. High levels of amikacin above the minimum inhibitory concentration for susceptible bacteria were detected when applied subconjunctivally and by 250 mg/ml topical fortified routes. Topical fortified amikacin 250 mg/ml reached the highest value in the aqueous (p < 0.05). Our results point out the poor corneal penetration of amikacin in standard concentrations from the intact rabbit cornea and that subconjunctival injections might provide satisfactory penetration.

Clinicopathologic Study of Satellite Lesions in Nontuberculous Mycobacterial Keratitis

Multifocal stromal infiltrates or “satellite lesions” have been considered a characteristic feature of fungal keratitis. We examined two patients with nontuberculous mycobacterial keratitis who clinically presented with satellite lesions. The keratitis consisted of multifocal stromal infiltrates with indistinct white and fluffy margins. Both patients received topical fortified amikacin therapy with poor response. Lamellar keratectomy or penetrating keratoplasty was performed, respectively, in the two patients because of progressive stromal thinning and enlarging satellite lesions. Histopathologically, the main lesions consisted of dense infiltration of inflammatory cells with numerous acid-fast bacilli, while the satellite lesions were composed chiefly of inflammatory cells with fewer mycobacteria. Besides fungal keratitis, nontuberculous mycobacterial keratitis should also be considered when satellite lesions are present.

Topical ciprofloxacin for treating nontuberculous mycobacterial keratitis

This study aimed to evaluate the clinical efficacy of topical ciprofloxacin for treating Mycobacterium fortuitum and Mycobacterium chelonae keratitis refractory to amikacin therapy. A prospective clinical trial of topical ciprofloxacin treatment for nontuberculous mycobacterial keratitis was conducted. Eleven patients with nontuberculous mycobacterial keratitis diagnosed from 1992 to 1996 were enrolled. All 11 patients were treated initially with topical fortified amikacin, but only 2 patients responded. The other nine patients, four with M. fortuitum and five with M. chelonae keratitis, were refractory to amikacin therapy and received topical ciprofloxacin treatment. Bacterial culture and drug susceptibility tests using the broth microdilution method were performed on all 11 patients. The clinical response to amikacin or ciprofloxacin treatment was judged by corneal re-epithelialization and density and/or size of corneal infiltrates. M. chelonae isolates were more resistant to amikacin and ciprofloxacin than M. fortuitum isolates based on the in vitro susceptibility test. Clinically, three patients with M. fortuitum keratitis were responsive to ciprofloxacin therapy; however, only one patient with M. chelonae keratitis responded to the same therapy. Topical ciprofloxacin offers a therapeutic alternative for nontuberculous mycobacterial keratitis, which was refractory to amikacin treatment. However, topical ciprofloxacin was more effective for treating M. fortuitum keratitis than for M. chelonae keratitis.

Mycobacterium chelonae Keratitis

We report a case of Mycobacterium chelonae keratitis following corneal injury by a foreign body. Diagnosis was made by Ziehl-Neelsen staining and Löwenstein-Jensen culture of corneal scrapings. On the basis of the in vitro susceptibility testing, the patient was treated with topical fortified amikacin. Given the lack of response to this therapy, we decided to carry out a debridement of the infiltrative areas to eliminate infected tissue, and to use an amikacin-soaked collagen shield supplemented every 4 h with topical fortified amikacin to promote healing of the debrided area and to potentiate the effects of the antibiotic therapy. After this treatment, clinical resolution was observed and a further acid-fast stain and culture for mycobacterium were negative. Debridement of the infiltrative areas could be used in cases of mycobacterium keratitis when early diagnosis is made and before the corneal infection has become widespread.

Mycobacterium chelonei Keratitis After Radial Keratotomy

Two patients who had undergone radial keratotomy developed delayed postoperative infectious keratitis. Both patients had surgery at the same outpatient facility, and their procedures had been performed by the same surgeon. The corneal lesions appeared similar in both cases, consisting of white irregular infiltrates with radiating projections and fluffy, indistinct margins. Although they were found at all levels, the lesions were most concentrated in the mid-to-deep stroma and were associated with overlying epithelial defects. In both cases, Mycobacterium chelonei was isolated from corneal biopsy specimens. Both patients were treated with topical fortified amikacin; in one there was complete resolution of the corneal infiltrates with medical therapy alone. Although the other patient's lesions initially appeared to resolve with medical therapy, she eventually required corneal transplantation because of recurrence of the infiltrates. Histopathologically, the infiltrates consisted of myriads of acid-fast bacteria with rare inflammatory cell infiltrations.

A case of nocardia keratitis treated successfully with topical amikacin

Keratitis caused by the nocardia species is rare in clinical practice and can cause confusion during treatment because it often mimics fungal keratitis. This is a case of nocardia keratitis occurring in a forty-year-old lady without any predisposing factors. It was initially treated as fungal keratitis, then as herpes simplex viral keratitis, but once the organism was known, it was successfully treated with topical fortified amikacin 14 mg/ml (1.4 %). Delay in diagnosis can occur in nocardia keratitis due to its rarity in occurrence. It responds well if proper therapy is instituted on time.