Successful management of severe post-LASIK Mycobacterium abscessus keratitis with topical amikacin and linezolid, flap ablation, and topical corticosteroids

Infectious Keratitis After Keratorefractive Surgery: Update and Review of the Literature

OBJECTIVES

To summarize the clinical manifestations, microbiological profile, treatment, and prognosis of corneal infections after different keratorefractive surgery.

METHODS

To obtain relevant studies, English-language databases, including PubMed, Ovid Embase, Web of Science, and CLNAHL, were searched from January 1979 to March 2022. The fundamentals of the literature, clinical characteristics, pathogens, and treatments were retrieved for each included article.

RESULTS

Eighty-four studies involving 306 infectious eyes were included in this review. Risk factors of potential infection included a history of blepharitis, contact lens usage, and contaminated surgical instruments. The mean onset time was 22.9±38.7 days (range: 1 day to 3 years). The most common organism isolated from infectious keratitis after keratorefractive surgery were Staphylococcus aureus , followed by Mycobacterium and coagulase-negative Staphylococcus . Most of the infections after refractive procedures were sensitive to medical treatment alone, and the ultimate best-corrected visual acuity after medical treatment was as follows: 20/20 or better in 82 cases (37.0%), 20/40 or better in 170 cases (76.5%), and worse than 20/40 in 52 cases (23.5%). Surgical interventions including flap lift, flap amputation, ring removal, and keratoplasty were performed in 120 eyes (44.5%).

CONCLUSIONS

Most infections after keratorefractive surgery occur within a week, whereas more than half of the cases after laser-assisted in situ keratomileusis happen after about a month. Gram-positive cocci and mycobacterium are the most common isolates. Infections after LASIK, intracorneal ring (ICR) implantation, and small incision lenticule extraction, which primarily occur between the cornea layers, require irrigation of the tunnels or pocket with antibiotics.

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.

Bacterial keratitis: identifying the areas of clinical uncertainty

Bacterial keratitis is a common corneal infection that is treated with topical antimicrobials. By the time of presentation there may already be severe visual loss from corneal ulceration and opacity, which may persist despite treatment. There are significant differences in the associated risk factors and the bacterial isolates between high income and low- or middle-income countries, so that general management guidelines may not be appropriate. Although the diagnosis of bacterial keratitis may seem intuitive there are multiple uncertainties about the criteria that are used, which impacts the interpretation of investigations and recruitment to clinical studies. Importantly, the concept that bacterial keratitis can only be confirmed by culture ignores the approximately 50% of cases clinically consistent with bacterial keratitis in which investigations are negative. The aetiology of these culture-negative cases is unknown. Currently, the estimation of bacterial susceptibility to antimicrobials is based on data from systemic administration and achievable serum or tissue concentrations, rather than relevant corneal concentrations and biological activity in the cornea. The provision to the clinician of minimum inhibitory concentrations of the antimicrobials for the isolated bacteria would be an important step forward. An increase in the prevalence of antimicrobial resistance is a concern, but the effect this has on disease outcomes is yet unclear. Virulence factors are not routinely assessed although they may affect the pathogenicity of bacteria within species and affect outcomes. New technologies have been developed to detect and kill bacteria, and their application to bacterial keratitis is discussed. In this review we present the multiple areas of clinical uncertainty that hamper research and the clinical management of bacterial keratitis, and we address some of the assumptions and dogma that have become established in the literature.

Severe Pulmonary Mycobacterium abscessus Cases Due to Co-Infection with Other Microorganisms Well Treated by Clarithromycin and Sitafloxacin in Japan

Background

Mycobacterium abscessus frequently causes severe infections, yet its pathophysiological features and treatment regimens have not been established.

Case Report

We present five cases of severe pneumonia due to Mycobacterium abscessus infection in Japan. All cases were diabetic patients, with possible acceleration to pneumonia due to co-infection with other microorganisms. However, following a short period of hospitalization and combination therapy with intravenous imipenem/cilastatin and amikacin, all the cases were successfully treated as outpatients with oral clarithromycin and sitafloxacin.

Conclusion

M. abscessus infections can become severe in the presence of diabetes mellitus and co-infection with other chronic infectious organisms. Sitafloxacin might be a key drug in the treatment of M. abscessus infection in future.

Mycobacterium abscessus Associated Peritonitis with CAPD Successfully Treated Using a Linezolid and Tedizolid Containing Regimen Suggested Immunomodulatory Effects

Patient: Female, 38-year-old

Final Diagnosis: Peritonitis

Symptoms: Abdominal and/or epigastric pain

Medication:—

Clinical Procedure: —

Specialty: Infectious Diseases

Treatment-Resistant Bacterial Keratitis: Challenges and Solutions

Bacterial keratitis is an important ophthalmic emergency and one of the most common causes of corneal blindness. The main causes of treatment resistance in bacterial keratitis are failure to eliminate predisposing factors, misdiagnosis and mistreatment. At first, exogenous, local and systemic predisposing factors that disturbing ocular surface must be eliminated to improve corneal ulcers and to prevent recurrences. Smears and scrapings for staining and culture are indispensable diagnostic tools for cases of sight-threatening keratitis (centrally located, multifocal, characterized by melting, painful). Main treatment agents in bacterial keratitis treatment are topical antibiotics. Until the results of culture antibiograms reach the ophthalmologist, empirical antibiotic selections based on direct microscopic examination and gram stain findings are the most appropriate initial treatment approach currently. S. aureus and coagulase-negative staphylococci (CoNS), the most common gram-positive agents, have resistance rates of more than 30% for fluoroquinolone and methicillin. Multidrug resistance rates are similarly high in these microorganisms. P. aeruginosa is the most common gram-negative micro-organism, in case of multidrug-resistant isolates, both functional and anatomical prognosis of the eyes are very poor. In cases of sight-threatening and resistant keratitis, antibiotic susceptibility testing containing imipenem, colistin, and linezolid is seeming to be an important requirement. Despite its efficiency limited to superficial cases, a nonpharmaceutical anti-infective treatment option such as corneal crosslinking for bacterial keratitis is an emerging hope, while antibiotic resistance increases.

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Looking beyond Typical Treatments for Atypical Mycobacteria

The genus Mycobacterium comprises not only the deadliest of bacterial pathogens, Mycobacterium tuberculosis, but several other pathogenic species, including M. avium and M. abscessus. The incidence of infections caused by atypical or nontuberculous mycobacteria (NTM) has been steadily increasing, and is associated with a panoply of diseases, including pulmonary, soft-tissue, or disseminated infections. The treatment for NTM disease is particularly challenging, due to its long duration, to variability in bacterial susceptibility profiles, and to the lack of evidence-based guidelines. Treatment usually consists of a combination of at least three drugs taken from months to years, often leading to severe secondary effects and a high chance of relapse. Therefore, new treatment approaches are clearly needed. In this review, we identify the main limitations of current treatments and discuss different alternatives that have been put forward in recent years, with an emphasis on less conventional therapeutics, such as antimicrobial peptides, bacteriophages, iron chelators, or host-directed therapies. We also review new forms of the use of old drugs, including the repurposing of non-antibacterial molecules and the incorporation of antimicrobials into ionic liquids. We aim to stimulate advancements in testing these therapies in relevant models, in order to provide clinicians and patients with useful new tools with which to treat these devastating diseases.

Mycobacterium abscessus subsp. bolletii keratitis: rare case reported in Brazil

In this report, we described a rare case of Mycobacterium abscessus subsp. bolletii keratitis in a young healthy male, in the absence of risk factors.