Ocular infections in sub-Saharan Africa in the context of high HIV prevalence

Recent advances of aggregation‐induced emission in body surface organs

The surface organs mainly comprise the superficial layers of various parts of the mammalian body, including the skin, eyes, and ears, which provide solid protection against various threats to the entire body. Damage to surface organs could lead to many serious diseases or even death. Currently, despite significant advancements in this field, there remain numerous enigmas that necessitate expeditious resolution, particularly pertaining to diagnostic and therapeutic objectives. The advancements in nanomedicine have provided a significant impetus for the development of novel approaches in the diagnosis, bioimaging, and therapy of superficial organs. The aggregation‐induced emission (AIE) phenomenon, initially observed by Prof. Ben Zhong Tang, stands out due to its contrasting behavior to the aggregation‐caused quenching effect. This discovery has significantly revolutionized the field of nanomedicine for surface organs owing to its remarkable advantages. In this review of literature, we aim to provide a comprehensive summary of recent advances of AIE lumenogen (AIEgen)‐based nanoplatforms in the fields of detection, diagnosis, imaging, and therapeutics of surface organ‐related diseases and discuss their prospects in the domain. It is hoped that this review will help attract researchers’ attention toward the utilization of this field for the exploration of a wider range of biomedical and clinical applications.

Ocular manifestations of people living with HIV in Tunisia

Background

Ocular involvement is a common complication of human immunodeficiency virus (HIV). Knowledge about this topic in Tunisia is limited.

Objective

To investigate ophthalmic manifestations in patients living with HIV in Tunisia.

Method

This was an observational study, performed between January 2007 and December 2016. We included patients with ocular disorders related to HIV. The data were recorded retrospectively from chart review.

Results

Amongst 98 people living with HIV (PLWH), 36 participants (55 eyes) had ocular manifestations. The mean age was 32.2 ± 5.6 years. Twenty-four patients were men and 12 were women. The mean value of CD4+ T-cell count was 156.5 ± 4.2 cells/µL. Bilateral lesions were found in 19 eyes. Best corrected visual acuity was better than 6/12 in 36 eyes. The most common ocular finding was dry eye syndrome (22%), cotton-wool spots (20%) and retinal haemorrhage (16%) followed by cytomegalovirus (CMV) retinitis (9%), anterior uveitis (7%), toxoplasmosis (4%) and tuberculosis retinochoroiditis (7%) Herpetic keratitis (5%), Herpes zoster ophthalmicus (2%) and syphilitic chorioretinitis (2%). Papilledema was found in three eyes (5%). Panuveitis was observed in four eyes (7%): three of them were associated with chorioretinal toxoplasmosis, syphilitic chorioretinitis and CMV retinitis. The fourth was attributable to immune recovery uveitis. A CD4+ T-cell count of ≤ 200 cells/µL was found to be an independent risk factor for developing posterior segment manifestations.

Conclusion

Various ophthalmic manifestations were observed in PLWH. The most common lesion was retinopathy. Ocular involvement can be serious leading to poor visual prognosis, which requires close collaboration between the ophthalmologist and infectious disease physician.

Common bacterial causes of external ocular infections, associated risk factors and antibiotic resistance among patients at ophthalmology unit of Felege Hiwot Referral Hospital, Northwest Ethiopia: a cross-sectional study

BACKGROUND

Ocular infections are a serious public health problem in Ethiopia with increased incidence of morbidity and blindness. Empirical therapy with topical ophthalmic broad spectrum antibiotic formulations is also a prevailing practice. The aim of this study was to determine the bacterial causes of external ocular infections (EOIs), antimicrobial resistance and its associated risk factors among patients at Felege Hiwot Referral Hospital, Northwest Ethiopia.

METHODS

A hospital based cross - sectional study was conducted from 1 February to 30 April 2019. Patients with EOIs were consecutively included from 1 February to 30 April, 2019. Data were collected using structured questionnaire by face-to-face interview and complemented with patient card review. Conjunctival, eyelid margin and lacrimal sac swabs were collected aseptically. Bacterial species were identified using standard bacteriological techniques. Antimicrobial susceptibility testing was done using Kirby-Bauer disk diffusion method. Binary logistic regression analysis was calculated to identify the factors associated with EOIs. P.value (p) < < 0.05 was considered as statistically significant.

RESULTS

A total of 360 patients took part in the study and majority of them were males (64.7%). The median age of study participants was 59.5 years. Overall, 208(57.8%) (95%CI = 52.6- - 62.8%) of patients had culture confirmed bacterial EOIs. The proportion of culture confirmed EOIs was 60.4% among conjunctivitis cases and 55.8% among blepharitis. Ocular trauma (P < < 0.001), ocular disease (P < < 0.001) and having eye allergy (P = 0.027) were significantly associated with EOIs. The most frequent isolates were S. aureus (37%), K. pneumoniae (13.5%), Proteus(7.2%) spp., S. pneumoniae (4.3%), Citrobacter spp. (3.4%) and P. aeruginosa (2.9%). Gram positive isolates were resistant to penicillin in 87% and ampicillin in 86.2%. Gram negative isolates were resistant to ampicillin (87.5%). P.aeruginosa isolates (85.3%) were resistant to piperacillin and 50% were resistant to tobramycin. Overall, 45.2% of the isolates were multi-drug resistant. The percentage of multi-drug resistance was 80% among Enterobacter isolates and 64.3% among K. pneumoniae.

CONCLUSIONS

Bacterial external ocular infections linked with multi-drug resistance and resistance to penicillin, ampicillin, tetracycline and piperacillin are high. Therefore, empirical treatment of eye infections in the study area needs to be monitored by regular antimicrobial-susceptibility testing of isolates.

The Changing Global Epidemic of HIV and Ocular Disease

Purpose: Overview of the evolving epidemiology of human immunodeficiency virus (HIV)-related ocular disease over time. Method: Narrative review. Results: HIV enhances susceptibility to opportunistic eye infections, has direct pathogenic effects, and places patients at risk of immune recovery inflammatory syndromes in previously infected eyes after starting highly-active antiretroviral therapy (HAART). Widespread availability of HAART has resulted in a decrease of infectious ocular conditions such as cytomegalovirus retinitis, toxoplasmic retinitis, squamous cell carcinoma of the conjunctiva, and microvascular retinopathy. However, large coexisting burdens of tuberculosis, herpesvirus infection and syphilis (among others) continue to contribute to the burden of ocular disease, especially in low-resource settings. Growing risks of cataract, retinopathy and retinal nerve fiber thinning can affect patients with chronic HIV on HAART; thought due to chronic inflammation and immune activation. Conclusion: The changing epidemic of ocular disease in HIV-infected patients warrants close monitoring and identification of interventions that can help reduce the imminent burden of disease.

Outcome of therapeutic deep anterior lamellar keratoplasty in advanced Acanthamoeba keratitis

Purpose

To report and analyze the outcomes of therapeutic deep anterior lamellar keratoplasty (DALK) in patients with advanced Acanthamoeba keratitis (AK).

Methods

Medical records of microbiologically confirmed AK, underwent DALK from 2004 to 2017, were reviewed and the data related to early and late outcome including complications were retrieved. Outcome of cases with largest diameter of infiltrate ≥8 mm at the time of surgery (advanced keratitis) were analyzed and compared with those with less severe keratitis (infiltrate size less than 8 mm).

Results

Out of 23 patients of AK in whom DALK was performed, ten (43.4%) patients had advanced keratitis. Mean age of these patients was 38.7 ± 8.6 years (range, 25 to 56). Median visual acuity at presentation was 2.78 (IQR, 1.79-3.0) that improved to 1.79 (IQR, 0.70-2.78) postoperatively. Early complications included recurrence of AK in 2 (20%), Descemet's membrane detachment in 5 (50%), and persistent epithelial defect in 3 (30%) cases. Overall, 6 (60%) grafts failed, whereas 4 (40%) patients had clear graft at their last follow-up. Median follow-up of these cases was 5 months (IQR, 1.4-11.4). One graft developed stromal rejection, which resolved with increased dose of corticosteroids. In comparison, DALK performed for less severe keratitis (N = 13) had 1 (7.6%) recurrence and 2 (15.8%) grafts failure (OR, 8.25). The probability of one-year graft survival and eradication of infection was 32% and 74.1%, respectively, in advanced cases compared to 91.6% and 83.9% in less severe cases.

Conclusion

Outcome of DALK in advanced Acanthamoeba keratitis is less favorable compared to those carried out for less severe keratitis cases.

The Spectrum of Microbial Keratitis: An Updated Review

Background:

In microbial keratitis, infection of the cornea can threaten vision through permanent corneal scarring and even perforation resulting in the loss of the eye. A literature review was conducted by Karsten, Watson and Foster (2012) to determine the spectrum of microbial keratitis. Since this publication, there have been over 2600 articles published investigating the causative pathogens of microbial keratitis.

Objective:

To determine the current spectrum of possible pathogens implicated in microbial keratitis relative to the 2012 study.

Methods:

An exhaustive literature review was conducted of all the peer-reviewed articles reporting on microbial pathogens implicated in keratitis. Databases including MEDLINE, EMBASE, Scopus and Web of Science were searched utilising their entire year limits (1950-2019).

Results:

Six-hundred and eighty-eight species representing 271 genera from 145 families were implicated in microbial keratitis. Fungal pathogens, though less frequent than bacteria, demonstrated the greatest diversity with 393 species from 169 genera that were found to cause microbial keratitis. There were 254 species of bacteria from 82 genera, 27 species of amoeba from 11 genera, and 14 species of virus from 9 genera, which were also identified as pathogens of microbial keratitis.

Conclusion:

The spectrum of pathogens implicated in microbial keratitis is extremely diverse. Bacteria were most commonly encountered and in comparison, to the review published in 2012, further 456 pathogens have been identified as causative pathogens of microbial keratitis. Therefore, the current review provides an important update on the potential spectrum of microbes, to assist clinicians in the diagnosis and treatment of microbial keratitis.

Opportunistic ocular infections in the setting of HIV

PURPOSE OF REVIEW

The aim of this review is to highlight recent changes in opportunistic ocular infections (OOIs) in the era of modern combination antiretroviral therapy (cART), in the setting of HIV-infected patients.

RECENT FINDINGS

Improvements in modern cART has led to a progressive decline in the incidence of OOIs and mortality among patients with AIDS. Not only has there been a decreasing incidence of cytomegalovirus (CMV) retinitis, but there also has been a decline in progression of such retinitis when it does occur in AIDS patients, since the introduction of cART. Nevertheless, CMV retinitis remains the major cause of vision loss in AIDS patients. Although the incidence of CMV retinitis has declined overall, the incidence of ocular syphilis has increased during the cART era. Moreover, the impact of having HIV plays a role with respect to multidrug-resistant (MDR) tuberculosis and has resulted in a high prevalence of presumed ocular tuberculosis in HIV/MDR-TB co-infected patients. Although immune reconstitution uveitis (IRU) has been an important cause of visual deficits in developed countries, OOIs remain an important cause of blindness in the developing world.

SUMMARY

Reconstituting the immune system with effective cART while increasing accessibility of screening examinations is key to the success of blindness prevent in HIV-infected individuals, particularly in developing countries.

Microbial contamination of multiple-use bottles of fluorescein ophthalmic solution

BACKGROUND

The contamination of ophthalmic solutions in ophthalmic practices remains an important cause of a myriad of secondary eye infections and a source of aggravation of ocular disorders such as corneal ulcers and keratitis. The aim of this study was to investigate the possible microbial contamination of fluorescein sodium dye solutions used in eye clinics in Ghana.

METHODS

Fluorescein sodium solutions were collected from various eye clinics in Ghana. Twenty-one samples of multiple-use fluorescein ophthalmic solutions were collected from various regions in Ghana. Eighteen unopened bottles yet to be used were also collected to serve as controls from the same facilities. The solutions were inoculated in different culture plates (blood agar, MacConkey agar, Sabouraud dextrose agar and plate count agar). The resulting microbial growth was identified using standard microbial identification techniques. Susceptibility tests were performed to ascertain the clinical importance of the organisms identified.

RESULTS

Positive cultures were recorded for all 21 multiple-use bottles (in-use) collected, but there were no positive cultures for the unopened bottles (yet to be used). Six different genera of bacteria were identified from fluorescein solutions, including resistant strains of Staphylococci spp., Bacillus spp., Klebsiella spp., Pseudomonas spp., Haemophilus spp. and Bordetella spp. Pseudomonas spp. were the most common bacterial contaminants. For fungi contaminations, Aspergillus spp., Penicillium spp. and Cladosporium spp. were isolated. The most common fungal contaminants were Aspergillus spp.

CONCLUSIONS

Multiple-use bottles of fluorescein solution used in eye clinics in Ghana were contaminated with clinically important strains of bacteria and fungi.

Patterns of Uveitis at Two University-Based Referral Centres in Cape Town, South Africa

Purpose: To analyze the pattern of uveitis at two tertiary hospitals in South Africa which has a high prevalence of HIV, TB and syphilis. Methods: Data of 198 patients were obtained retrospectively between August 2014 and August 2016, including patient demographics, clinical examination, special investigations and final diagnosis. Results: Infectious uveitis was the most common aetiological category (47%), followed by idiopathic (34.8%) and non-infectious (18.2%). Syphilis was the most common identifiable cause (16.2%). Other important causes were toxoplasmosis, herpes viruses, tuberculosis and HLA-B27. HIV positive patients, who constituted 40% of the study population, were more likely to present with a posterior or panuveitis (relative risk 1.50, 95% CI 1.19-1.89) and more likely to have an infectious cause compared to HIV negative patients (relative risk 2.47, 95% CI 1.82-3.35). Conclusions: This study emphasizes the importance of HIV testing and investigations for infectious causes of uveitis, especially syphilis, in this population.

A Focus on the Epidemiology of Uveitis

PURPOSE

Uveitis is a common, sight-threatening inflammatory ocular disease and includes multiple heterogeneous clinical entities. The prevalence of various types of uveitis depends upon multiple factors, such as age, sex, race, geographic distribution, environmental influence, genetics, and social habits. Epidemiologic research of uveitis is necessary to understand the etiology and immunopathogenesis of this group of diseases. The present study attempts to concentrate on the most recent information on the epidemiology of uveitis and compare it with previous knowledge.

METHODS

An extensive literature search was performed in the Medline database (PubMed) and included surveys completed until 2015. Articles that reported prevalence and incidence were studied. References cited in the articles were also studied.

RESULTS

The incidence and prevalence of uveitis differs based on age, anatomic location of the inflammatory process (anterior, intermediate, posterior uveitis, panuveitis), gender, histopathology (granulomatous, non-granulomatous), type of inflammatory process (acute, chronic, recurrent), and etiology (infectious, non-infectious). Prevalence differs by geographic location. Idiopathic anterior uveitis is the most common form of uveitis in the community. Infectious causes are common (30-60%) in the developing countries. Herpes and toxoplasmosis are the leading infectious causes of uveitis. Non-infectious uveitic conditions are generally more common in the developed world. An increase in the prevalence of infectious etiologies, including tuberculosis and syphilis, has been seen in developed countries. Introduction of new treatment options has also changed patterns of disease.

CONCLUSIONS

Introduction of new uveitis entities, changes in the incidence of already known disease and increased availability of diagnostic testing have all altered the epidemiology of uveitis in recent years. Knowledge of regional patterns of disease is essential. A more detailed classification of uveitis with the establishment of uniform diagnostic criteria and prospective population based studies would certainly benefit epidemiologic research and clinical practice.

Uveitis is predominantly of infectious origin in a high HIV and TB prevalence setting in rural South Africa

AIMS

To determine the burden of disease in a unique sample of patients with uveitis from a rural South African setting.

METHODS

Data in this cross-sectional study were collected from patients presenting with uveitis (n=103) at the ophthalmology outpatient department of three hospitals in rural South Africa. Demographic and clinical data were collected, and laboratory analysis of aqueous humour, serological evaluation and routine diagnostics for tuberculosis (TB) were performed.

RESULTS

Sixty-six (64%) participants were HIV infected. Uveitis was predominantly of infectious origin (72%) followed by idiopathic (16%) and autoimmune (12%). Infectious uveitis was attributed to herpes virus (51%), Mycobacterium tuberculosis (24%) and Treponema pallidum (7%) infection. HIV-infected individuals were more likely to have infectious aetiology of uveitis compared with HIV-uninfected individuals (83% vs 51%; p=0.001).

CONCLUSIONS

Microbial aetiology of uveitis is common in areas where HIV and TB are endemic. In these settings, a high index of suspicion for infectious origin of uveitis is warranted.

Good visual outcome of tuberculous chorioretinitis after ART initiation in a HIV-infected patient

Mycobacterium tuberculosis infection is an important cause of sight-threatening chorioretinitis in HIV-infected individuals living in M. tuberculosis endemic areas. We present a case of tuberculous chorioretinitis in a HIV-infected man after recent initiation of antiretroviral therapy in rural South Africa, who had nearly complete resolution of clinical signs and symptoms after standard tuberculosis treatment. His presentation was most likely associated with immune reconstitution inflammatory syndrome.