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

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

PURPOSE

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Late onset of microbial keratitis after laser in situ keratomileusis surgery: case series

PURPOSE

To report predisposing factors, clinical features, microbiology spectrum, antibiotic resistance, antimicrobial therapy, and outcomes of patients with a previous laser in situ keratomileusis (LASIK) surgery and diagnosed with presumed microbial keratitis.

SETTING

Sydney Eye Hospital, Sydney, New South Wales, Australia.

DESIGN

Retrospective case review.

METHODS

Patients were identified from pathology and hospital coding data from 2012 to 2016. Inclusion criteria were all patients with a previous LASIK surgery, a presumed diagnosis of microbial keratitis, and a corneal scrape performed and aged older than 18 years. Demographics, clinical details, and outcomes were collated from the medical records.

RESULTS

Sixteen patients were included, with median age of 41.5 years (range 22 to 85 years) and 56.2% of women. The median time between LASIK procedure and microbial keratitis presentation was 38.3 months (interquartile range 6.7 to 77.45 months). Cultures were positive for bacteria in 12 (75%) of 16 scrapes. Of the bacterial isolates, 12 (85.7%) were gram-positive and 2 (14.3%) gram-negative. Sensitivity profiles for the isolated bacteria were similar between fortified antibiotics (cefalotin and gentamicin) and commercial products (chloramphenicol and ofloxacin). Complications included the need for tectonic grafts, nonhealing epithelial defects, thinning, and neovascularization.

CONCLUSIONS

Late onset of keratitis after LASIK can occur with no positive cultures for nontuberculous mycobacteria, no interface involvement, and no other usual features reported in case series of infectious keratitis in LASIK patients. It has a similar clinical course to non-LASIK keratitis, such that the surgery may not have been a risk factor for infection.

Bilateral Non-tuberculous Mycobacterial Keratitis After Small Incision Lenticule Extraction

PURPOSE

To report a case of bilateral non-tuberculous mycobacterial keratitis after small incision lenticule extraction (SMILE) that was successfully treated with oral and topical fortified antibiotics.

METHODS

Case report and literature review.

RESULTS

An otherwise healthy 21-year-old woman presented with culture-proven bilateral Mycobacterium abscessus keratitis 8 days after undergoing SMILE, showing multiple white stromal infiltrates in the interface in both eyes. Progressive, diffuse flap edema followed by pocket abscess, exudation in the anterior chamber, granulation tissue formation in the pocket, intrastromal neovascularization, and eventually partial resolution of corneal opacity were noted after topical and oral antibiotic treatment for 6 months. Her corrected distance visual acuity was 20/32 and 20/50 in the right and left eyes, respectively, 12 months after initial presentation.

CONCLUSIONS

This is the first report of successful medical management of bilateral non-tuberculous mycobacterial keratitis after SMILE. The manifestations are different from and even more difficult to treat than those of keratitis after LASIK. [J Refract Surg. 2018;34(9):633-636.].

Identification of the Infection Source of an Outbreak of Mycobacterium Chelonae Keratitis After Laser in Situ Keratomileusis

PURPOSE

Nontuberculous mycobacteria keratitis is a rare but challenging complication of laser in situ keratomileusis (LASIK). This study was conducted to determine the source(s) of infection in a cluster of cases of keratitis after LASIK and to describe this outbreak and patients' outcomes.

METHODS

In this retrospective, case series, single-center study, 86 patients were included who underwent LASIK or photorefractive keratectomy between December 2011 and February 2012. Corneal scrapes from the affected eyes, samples of tap and distilled water, water from the reservoir of the distilling equipment, steamer, and autoclave cassette; antiseptic and anesthetic solutions and surgical instrument imprints were cultivated in liquid and on solid media. Gram-negative bacteria and yeasts were identified using automated systems and mycobacteria by polymerase chain reaction-restriction enzyme analysis of the hsp65 gene (PRA-hsp65) and DNA sequencing. Mycobacterial isolates were typed by pulsed-field gel electrophoresis. The cases and outcomes are described. The main outcome measure was identification of the source(s) of the mycobacterial infections.

RESULTS

Eight (15 eyes) of 86 patients (172 eyes) who underwent LASIK developed infections postoperatively; no patients who underwent photorefractive keratectomy developed infections. Mycobacterium chelonae was isolated from 4 eyes. The distilled water collected in the surgical facility contained the same M. chelonae strain isolated from the patients' eyes. Different gram-negative bacteria and yeasts were isolated from samples collected at the clinic but not from the patients' eyes.

CONCLUSIONS

Tap water distilled locally in surgical facilities may be a source of infection after ocular surgery and its use should be avoided.

Bilateral Mycobacterium chelonae Keratitis after Phacoemulsification Cataract Surgery

The purpose of this manuscript is to report the case of an 81-year-old patient who presented with bilateral keratitis after phacoemulsification surgery. Cultures came back positive for Mycobacterium chelonae. Despite aggressive topical and systemic antimicrobial treatment, the patient developed a corneal perforation in both eyes, treated with corneal glue in the right eye and corneoscleral patch in the left eye. After two years of follow-up, patient was free of infection in the right eye with visual acuity of 20/200 and the left eye progressed to phthisis bulbi. We present an unusual case of bilateral Mycobacterium chelonae keratitis associated with phacoemulsification cataract surgery. This case represents the importance of making clinicians aware of this devastating infection and highlights the need for better management to improve outcomes.

Discovery of novel antimycobacterial drug therapy in biofilm of pathogenic nontuberculous mycobacterial keratitis

PURPOSE

The potential of slow-growing mycobacteria to form biofilms in human tissues contributes to the problem of establishing an effective treatment strategy. The purpose of this study was to examine new antibiotic strategies to enhance current treatment options for these infections.

METHODS

Sensitivities of Mycobacterium fortuitum ATCC 49404 and Mycobacterium chelonae ATCC 35752 were evaluated for different antimicrobials singly and in combination using broth microdilution and FICI (Fractional Inhibitory Concentration Index) synergy screening. Anti-biofilm effects were evaluated in an 8-well chamber slide biofilm model. The efficacy of a new treatment strategy was validated using the novel neutropenic mouse keratitis model and monitored by slit-lamp microscopy, confocal microscopy, and colony forming unit measurements.

RESULTS

We reported the very first evidence that these organisms develop corneal biofilms by the accumulation of extracellular DNA (eDNA) and the presence of microcolonies using a novel mycobacterial neutropenic mouse keratitis model. The combination of amikacin and gatifloxacin or besifloxacin was more effective than the current gold-standard drug, amikacin, and we developed a novel treatment strategy (amikacin + gatifloxacin + DNase), the destruction of biofilm matrix component, eDNA, which increased the efficacy of the new antibiotic combination for treating mycobacterial infection in in vitro (P = 0.002) and in vivo (P = 0.001) compared to its respective control.

CONCLUSION

Biofilms have a role in mycobacterial keratitis leading to poor treatment outcomes in clinical practice and the use of combination therapy (amikacin + gatifloxacin + DNase) could be a useful new treatment option.

Nontuberculous Mycobacteria in Saudi Arabia and Gulf Countries: A Review

Nontuberculous Mycobacteria (NTM) are causing growing health problems worldwide. This is indicated by an increasing amount of scientific reports showing not only well-identified species reemerging but also emergence of new species. The emergence and reemergence of NTM are particularly worrying in developing countries due to scarce published data and improper identification. Here we aimed to examine the main epidemiological aspects and diagnostic challenges associated with NTM in countries of the Gulf Cooperation Council (GCC) and compare these findings to the international arena findings. Data revealed that countries of the GCC are largely dominated by rapidly growing mycobacteria species such as M. fortuitum (29%) and M. abscessus (17%) with high rate of definitive respiratory diseases. On the other hand, most of the developed countries are dominated by slowly growing mycobacteria such as MAC, M. kansasii, and M. gordonae. More efforts are needed, however, to gain insights into NTM issues in countries of the GCC.

Biofilms of Pathogenic Nontuberculous Mycobacteria Targeted by New Therapeutic Approaches

Microbial infections of the cornea are potentially devastating and can result in permanent visual loss or require vision-rescuing surgery. In recent years, there has been an increasing number of reports on nontuberculous mycobacterial infections of the cornea. Challenges to the management of nontuberculous mycobacterial keratitis include delayed laboratory detection, low index of clinical suspicion, poor drug penetration, slow response to therapy, and prolonged use of antibiotic combinations. The ability of nontuberculous mycobacteria to evade the host immune response and the ability to adhere and to form biofilms on biological and synthetic substrates contribute to the issue. Therefore, there is an urgent need for new antimicrobial compounds that can overcome these problems. In this study, we evaluated the biofilm architectures for Mycobacterium chelonae and Mycobacterium fortuitum in dynamic flow cell chamber and 8-well chamber slide models. Our results showed that mycobacterial biofilms were quite resistant to conventional antibiotics. However, DNase treatment could be used to overcome biofilm resistance. Moreover, we successfully evaluated a new antimicrobial compound (AM-228) that was effective not only for planktonic mycobacterial cells but also for biofilm treatment and was compared favorably with the most successful “fourth-generation” fluoroquinolone, gatifloxacin. Finally, a new treatment strategy emerged: a combination of DNase with an antibiotic was more effective than an antibiotic alone.

Use of Topical Besifloxacin in the Treatment of Mycobacterium chelonae Ocular Surface Infections

PURPOSE

To present the clinical outcome of 3 cases of ocular surface infections by Mycobacterium chelonae treated with besifloxacin (0.6%, Besivance; Bausch & Lomb, Tampa, FL).

METHODS

In this retrospective review of a small case series, we reviewed the medical records of 3 clinical patients with M. chelonae infection involving the ocular surface. Besifloxacin was used as an adjunct in 2 cases of keratitis and as the principal therapeutic agent in a case of nodular conjunctivitis.

RESULTS

Two patients who presented with culture-proven M. chelonae keratitis initially had been treated with topical amikacin and oral clarithromycin for 6 months in the first case and for 2 months in the second without complete resolution. Topical besifloxacin was added as an adjunct therapy to amikacin with progressive weaning of clarithromycin. Both cases of keratitis eventually resolved without recurrence after discontinuation of topical amikacin and besifloxacin. A third patient presented with nodular conjunctival inflammation, which initially had been treated with topical ciprofloxacin and corticosteroids without improvement. One nodular lesion was excised and submitted for microbial culture, which revealed the growth of M. chelonae. Marked improvement of the conjunctivitis was noted after 3 weeks of treatment with topical besifloxacin. Complete resolution of the conjunctival nodules was achieved after 10 weeks of treatment with besifloxacin.

CONCLUSIONS

Topical besifloxacin seems to be a useful adjunct agent in the treatment of nontuberculous mycobacterial keratitis by M. chelonae and may be viable for use as a first-line agent in cases of nodular conjunctivitis by M. chelonae.

Nontuberculous Mycobacterial Ocular Infections: A Systematic Review of the Literature

Nontuberculous or atypical mycobacterial ocular infections have been increasing in prevalence over the past few decades. They are known to cause periocular, adnexal, ocular surface and intraocular infections and are often recalcitrant to medical therapy. These infections can potentially cause detrimental outcomes, in part due to a delay in diagnosis. We review 174 case reports and series on nontuberculous mycobacterial (NTM) ocular infections and discuss etiology, microbiology, risk factors, diagnosis, clinical presentation, and treatment of these infections. History of interventions, trauma, foreign bodies, implants, contact lenses, and steroids are linked to NTM ocular infections. Steroid use may prolong the duration of the infection and cause poorer visual outcomes. Early diagnosis and initiation of treatment with multiple antibiotics are necessary to achieve the best visual outcome.

Nontuberculous mycobacteria in Middle East: Current situation and future challenges

Nontuberculous mycobacteria (NTM) are a diverse group of bacterial species that are distributed in the environment. Many of these environmental bacteria can cause disease in humans. The identification of NTM in environmental sources is important for both clinical and epidemiological purposes. In this study, the distribution of NTM species from environmental and clinical samples in the Middle East was reviewed. In order to provide an overview of NTM, as well as recent epidemiological trends, all studies addressing NTM in the Middle East from 1984 to 2014 were reviewed. A total of 96 articles were found, in which 1751 NTM strains were isolated and 1084 of which were obtained from clinical samples, 619 from environmental samples and 48 were cited by case reports. Mycobacterium fortuitum was the most common rapid growing mycobacteria (RGM) isolated from both clinical (269 out of 447 RGM; 60.1%) and environmental (135 out of 289 RGM; 46.7%) samples. Mycobacterium avium complex (MAC) was the most common slow growing mycobacteria (SGM) isolated from clinical samples (140 out of 637 SGM; 21.9%). An increasing trend in NTM isolation from the Middle East was noted over the last 5years. This review demonstrates the increasing concern regarding NTM disease in the Middle East, emphasizing the need for regional collaboration and coordination in order to respond appropriately.

Ocular penetration and pharmacokinetics of topical clarithromycin eye drops to rabbits

PURPOSE

To evaluate the ocular pharmacokinetics of clarithromycin (CLA) eye drops topically applied to the corneas of rabbits.

METHODS

One 50-μL drop of CLA (0.25%) was administered to each New Zealand white rabbit in a single dose group, and one 50-μL drop of CLA was administered 6 times at 5-min intervals to each rabbit in a loading dose group. The effect of debridement on corneal penetration was also investigated in a de-epithelium group. The drug concentrations in the cornea and aqueous humor (AH) were assayed using high-performance liquid chromatography with tandem mass spectrometry (HPLC-MS/MS) analysis.

RESULTS

Maximum CLA levels were achieved in the corneas and AH at 15 and 60 min, respectively, in the intact epithelium eyes in the single dose group (24.54±10.64 μg/g and 0.78±0.22 μg/mL, respectively, mean±the standard error of the mean, n=8). In the loading dose group, 30 min after the last application, the CLA level in the corneas reached 92.26±17.62 μg/g. In the loading dose group, the drug levels in the corneas and AH were significantly increased compared with the drug levels in the corneas with the intact epithelium and de-epithelium eyes in the single dose group at the corresponding time points (P<0.05). The estimated CLA half-lives in the corneas and AH for the intact eyes were 103.28 and 132.61 min, respectively.

CONCLUSION

Therapeutic CLA levels can be achieved in rabbit corneas after topically applying the drug with eye drops.

Non-tuberculous mycobacterial keratitis

Non-tuberculous mycobacteria are environmental, opportunistic pathogens that are increasingly being recognized as important causes of many human diseases. Among them, rapidly growing mycobacteria are the most notorious organisms causing infectious keratitis. Non-tuberculous mycobacterial (NTM) keratitis commonly occurs after trauma or refractive surgery, and can masquerade as fungal, herpetic or amoebic keratitis. Therefore, the diagnosis is often delayed. Prolonged medical treatment and judicious surgical debridement are required in order to eradicate the pathogens. Combination therapy with aminoglycosides, macrolides and fluoroquinolones improves the prognosis and decreases the occurrence of drug resistance. However, regardless of the development of new diagnostic techniques and antimicrobials, NTM keratitis remains a clinical challenge for most ophthalmologists. In this article, we provide a concise introduction to the epidemiological features and clinical characteristics of NTM keratitis, and the modern diagnostic tools used for it. We also summarize the current concepts of prevention and treatment for this potentially devastating condition.

Nontuberculous mycobacterial infection after clear corneal phacoemulsification cataract surgery: a report of 13 cases

PURPOSE

To review the patient profile, clinical presentation, management, and outcomes of nontuberculous mycobacterial (NTM) infection after clear corneal phacoemulsification.

METHODS

Review of consecutive cases diagnosed with NTM infection after phacoemulsification from 2004 to 2009. Demographic data, clinical characteristics, diagnosis, treatment, and outcomes were analyzed.

RESULTS

Thirteen eyes of 13 patients with mean age of 61.1 years, consisting of 7 men and 6 women were included. Twelve of 13 eyes (92%) underwent uncomplicated clear cornea phacoemulsification with posterior lens implant. Mean interval from surgery to onset of symptoms was 6.3 weeks, and time to referral ranged from 2 days to 9 months. Ten eyes (77%) presented with stromal wound abscess, whereas 3 (23%) appeared as iridocyclitis with posterior capsule plaques. Five eyes were clustered while the rest were isolated cases. All cases were culture positive for NTM. Two cases were treated medically, 3 had removal of lens implant and capsule, and 8 had penetrating keratoplasty with or without removal of lens implant, iridectomy, and/or pars plana vitrectomy. After a mean follow-up of almost 22 months, best-corrected visual acuity of 20/40 or better was achieved in half of the cases (54%). One case of recurrence was noted.

CONCLUSIONS

NTM infection should be suspected in patients presenting with corneal stromal wound abscess or iridocyclitis with posterior capsular plaques 6 to 7 weeks after phacoemulsification. Early diagnosis and treatment can lead to good outcomes, and management should include a combination of medical and surgical therapies.

Ocular infections caused by non-tuberculous mycobacteria: update on epidemiology and management

BACKGROUND

  To provide an update on the frequency, distribution, risk factors and in vitro susceptibility of ocular infections caused by non-tuberculous mycobacteria.

DESIGN

  Retrospective study of university clinic patients.

PARTICIPANTS

  One hundred thirty-nine patients with culture confirmed non-tuberculous mycobacteria infections seen at Bascom Palmer Eye Institute from January 1980 to July 2007.

METHODS

  Chart review of data collected included patients' demographics, risk factors, microbiological profiles and clinical outcomes.

MAIN OUTCOME MEASURES

  Frequency, distribution, risk factors and in vitro susceptibility of ocular infections caused by non-tuberculous mycobacteria.

RESULTS

  A total of 183 non-tuberculous mycobacteria isolates from 142 eyes were identified, with a fourfold increase in the number of eyes infected with non-tuberculous mycobacteria from 1980-1989 (13.4%) to 2000-2007 (56.3%). Eighty-three percent of non-tuberculous mycobacteria isolates were identified as M. abscessus/chelonae. The majority (91%) of isolates were recovered within 10 days. Common diagnoses included keratitis (36.6%), scleral buckle infections (14.8%) and socket/implant infections (14.8%). Identifiable risk factors were presence of biomaterials (63.1%), ocular surgery (24.1%) and steroid exposure (77%). The median time from diagnosis of culture positive non-tuberculous mycobacteria infection to resolution was 13 to 24 weeks. Combination therapy was used to treat 80% of infected eyes. In vitro susceptibility of non-tuberculous mycobacteria isolates were: amikacin, 81%; clarithromycin, 93%; and moxifloxacin, 21%.

CONCLUSIONS

  The incidence of ocular infections caused by non-tuberculous mycobacteria has increased within the last 8 years, with a high number of biomaterial associated infections among this group. Clinical diagnosis and microbiological confirmation of non-tuberculous mycobacteria infections remains challenging. Patient outcomes may be improved by early diagnosis, appropriate therapy and removal of biomaterials.

Comparison of fluoroquinolones: cytotoxicity on human corneal epithelial cells

PURPOSE

To compare the cytotoxicity of different fluoroquinolones (FQs) towards human corneal epithelial cells (HCECs).

METHODS

HCECs were incubated with FQs (norfloxacin, ciprofloxacin, ofloxacin, levofloxacin, moxifloxacin, and gatifloxacin), both as commercial ophthalmic formulations and as unpreserved solutions. Cells incubated in different formulations of gentamicin, cefazolin, and benzalkonium chloride (BAC) were also compared. A cell viability assay, using 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay, was used to evaluate the drug effects on cell viability after five incubation times (30 min, 1 h, 4 h, 8 h, and 24 h). Transepithelial electrical resistance (TEER) was measured with a voltohmmeter to help understand changes in paracellular permeability at five time points (4 h, 8 h, 12 h, 24 h, and 48 h). Cell morphology was observed with an inverted fluorescence microscope, with multiple stage position and in time-lapse mode.

RESULTS

The preserving solutions and BAC at concentrations above 0.005% significantly decreased cell viability, when assayed by MTS. Increased paracellular permeability and decreased membrane integrity were also observed by TEER measurements and inverted fluorescence microscopy. Ofloxacin and levofloxacin were both free of preservatives and showed the least cytotoxicity towards HCECs in commercial FQ eye drops.

CONCLUSIONS

The cytotoxicity observed with FQ eye drops seems to be caused mainly by the preservative, which induced a significant decrease in membrane integrity and increased paracellular permeability. We found the new generation of FQs (moxifloxacin and gatifloxacin) no less cytotoxic towards HCECs than the old generation ones.

Antibiotic susceptibility of conjunctival bacterial isolates from refractive surgery patients

PURPOSE

To determine the in vitro antibiotic susceptibility patterns of conjunctival bacterial flora isolated before surgery from patients undergoing refractive surgery.

DESIGN

In vitro laboratory investigation.

PARTICIPANTS

One hundred five eyes from 105 patients scheduled for refractive surgery at Balgensesang Ophthalmology Clinic between September 2005 and January 2006 were studied. Among 105 patients, 71 (67.6%) underwent LASIK using a femtosecond laser, 24 (22.9%) underwent LASIK using an automated microkeratome, 8 (7.6%) underwent LASEK, and 2 (1.9%) patients underwent phakic intraocular lens implantation.

METHODS

Preoperative conjunctival swab samples were inoculated directly in culture media at the bedside before topical anesthetic or antibiotic application. Blood agar, chocolate agar, thioglycolate broth, Sabouraud dextrose agar, and Ogawa media were used for bacterial, fungal, and mycobacterial cultures.

MAIN OUTCOME MEASURES

Minimum inhibitory concentrations (MICs) of ofloxacin (OFX), levofloxacin (LEV), gatifloxacin (GAT), moxifloxacin (MOX), gemifloxacin (GEM), and other commonly used antibiotics were determined using an E test.

RESULTS

From 105 patients, 73 (85%) coagulase-negative staphylococci (CNS), 2 (2.3%) Staphylococcus aureus, 1 (1.2%) Streptococcus pneumoniae, and 5 (4.8%) gram-negative bacilli were isolated. No fungi or mycobacteria were isolated. The MIC that would inhibit the growth of 90% of the tested bacterial isolates (MIC(90)) of OFX, LEV, GAT, MOX, and GEM for methicillin-susceptible CNS (n = 46) were 0.5 microg/ml, 0.19 microg/ml, 0.094 microg/ml, 0.047 microg/ml, and 0.023 microg/ml, respectively. The MIC(90) values for methicillin-resistant CNS (n = 27) were 32 microg/ml, 4 microg/ml, 1 microg/ml, 0.5 microg/ml, and 0.25 microg/ml, respectively (P<0.001).

CONCLUSIONS

The most effective against conjunctival bacteria isolated from refractive surgery patients were GEM, MOX, and GAT; however, resistance to earlier-generation fluoroquinolones (OFX and LEV) is increasing among methicillin-resistant CNS. It may be a therapeutic option to use newer fluoroquinolones in patients undergoing refractive eye surgery to reduce such infections as methicillin-resistant CNS.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Atypical mycobacteria keratitis after laser in situ keratomileusis unresponsive to fourth-generation fluoroquinolone therapy

We report a case of post-laser in situ keratomileusis atypical mycobacteria infection unresponsive and resistant to fourth-generation fluoroquinolones, which highlights the importance of a high level of suspicion and the need for multidrug therapy for effective eradication.

Infectious keratitis

PURPOSE OF REVIEW

Infectious keratitis is a medical emergency. Improper management can lead to marked loss of vision. This review identifies recent trends in the study of infectious keratitis.

RECENT FINDINGS

A multicountry outbreak of Fusarium keratitis emphasizes that contact lens wear is a major risk factor for infectious keratitis. Acanthamoeba and fungal keratitis are the most expensive forms of infectious keratitis to treat. Noninvasive methods and molecular techniques have improved diagnosis of infectious keratitis. Fortified topical antibiotics and fluoroquinolones are still the mainstay of bacterial keratitis therapy. Voriconazole and new routes of administration of conventional antifungals appear promising for fungal keratitis. Antivirals and amelioration of host inflammatory response are promising for viral keratitis; the host response is also crucial in pathogenesis of Pseudomonas aeruginosa keratitis. Trauma-induced bacterial and fungal keratitis and contact lens-associated keratitis are preventable entities.

SUMMARY

Improved modalities of diagnosis and treatment have improved the outcome of infectious keratitis, but therapy of acanthamoebal, fungal and P. aeruginosa keratitis is still a challenge. Effective strategies must neutralize potential risk factors and counter host response overactivity without impairing killing of infecting microorganisms. Trauma-induced bacterial and fungal keratitis can be prevented.

Infectious and noninfectious keratitis after laser in situ keratomileusis

PURPOSE

To retrospectively review the occurrence, treatment, and visual outcomes associated with various etiologies of keratitis as a postoperative complication of laser in situ keratomileusis (LASIK) at an academic surgical center.

SETTING

John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA.

METHODS

The charts of 5618 post-LASIK patients (10 477 eyes) were reviewed for the development of keratitis. Occurrence rates, management regimens, and final best spectacle-corrected visual acuity (BSCVA) were reported for infectious and noninfectious keratitis etiologies.

RESULTS

Post-LASIK keratitis was diagnosed in 279 eyes. The keratitis was diagnosed as infectious in 33 eyes (12%) and as noninfectious in 246 eyes (88%). Infectious cases included 5 eyes (15%) with herpes simplex keratitis (HSV), 18 (55%) with adenoviral keratitis, and 10 (30%) with nonviral (including bacterial, fungal, and parasitic) keratitis. Of noninfectious cases, 193 (78%) were classified as diffuse lamellar keratitis (DLK), 36 (15%) as staphylococcal marginal hypersensitivity, and 17 (15%) as localized debris-related keratitis.

CONCLUSIONS

The occurrence of post-LASIK keratitis was 2.66%, with DLK being the most common diagnosis overall. The occurrence of noninfectious keratitis (2.34%) was 7.5 times greater than the occurrence of infectious keratitis (0.31%). Adenoviral keratitis had the best visual outcomes overall, with all 18 patients achieving 20/20 BSCVA. In contrast, all 5 eyes with HSV keratitis lost 1 or 2 lines of BSCVA. Excluding adenoviral keratitis, infectious etiologies had significantly worse visual outcomes than noninfectious etiologies at the 20/40 and 20/20 levels (P = .0013 and P<.001, respectively).