Acanthamoeba T4 genotype associated with keratitis infections in Tunisia

Epidemiology of free-living amoebae infections in Africa: a review

FLA-related conditions are a rare medical occurrence. Despite their rarity, they are considered a public health concern for two reasons: the absence of a regular treatment regimen in the case of central nervous system infections and the fast progression of the symptoms leading to fatal outcomes. A total of 358 articles were retrieved from different databases (91 from PubMed, 26 from NCBI, 138 from Academia, 102 from Science Direct, and one from IJMED). 7 (46.6%) clinical cases came from Egypt, 2 (13.3%) cases of FLA infection came from Nigeria, 3 (20%) cases came from the Gambia, and 1 (6.6%) case was reported from African countries like Algeria, Tunisia, South Africa, and Zambia. Medical conditions caused by free-living amoeba are considered significant public health concerns. These ubiquitous organisms can cause both fatal and debilitating health conditions. Immediate diagnosis of cases and proper hygienic practices are necessary to provide direct medical intervention. They may be the key to reducing the morbidity and mortality rates from FLA-acquired infections. Although several government-led initiatives have been implemented to mitigate a plethora of parasitic diseases, the case of FLA-related conditions in African countries has yet to be realized.

Genotype distribution of Acanthamoeba in keratitis: a systematic review

Acanthamoeba spp. are among the most worldwide prevalent protozoa. It is the causative agent of a disease known as Acanthamoeba keratitis, a painful and severe sight-threatening corneal infection that can lead to blindness. In recent years, the prevalence of Acanthamoeba keratitis has rapidly increased, growing its importance to human health. This systematic review aims to assess the distribution of Acanthamoeba sp. genotypes causing keratitis around the world, considering the sample collected type and the used identification method. Most of the cases were found in Asia and Europe. Not surprisingly, the T4 genotype was the most prevalent worldwide, followed by T3, T15, T11, and T5. Furthermore, the T4 genotype contains a higher number of species. Given the differences in pathology, susceptibility to treatment, and clinical outcome between distinct genotypes, it is essential to genotype isolates from Acanthamoeba keratitis cases to help to establish a better correlation between in vitro and in vivo activities, resulting in better drug therapies and successful treatment in cases of this important ocular infection.

Cluster of Post-Operative Endophthalmitis Caused by Acanthamoeba T10 Genotype - A First Report

PURPOSE

To report a cluster of postoperative Acanthamoeba endophthalmitis after routine cataract surgeries.

METHODS

A brief summary of sentinel events leading to the referral of 4 patients of postoperative endophthalmitis to our hospital is followed by clinical descriptions and the various diagnostic approaches and interventions used. Genotyping and phylogenetic analysis are also discussed.

RESULTS

Four cases of postoperative cluster endophthalmitis, presumed to be bacterial and treated as such, were referred to our hospital. The presence of an atypical ring infiltrate in the first case facilitated the diagnosis of Acanthamoeba endophthalmitis. All patients had vitritis, corneal involvement, and scleral inflammation. Multiple diagnostic methods, such as corneal scrapings, confocal microscopy, aqueous and vitreous taps, scleral abscess drainage, histopathological studies, polymerase chain reaction, and genotyping and phylogenetic analyses of isolated Acanthamoeba, were used to confirm the diagnosis of endophthalmitis and to establish the extent of ocular involvement. Various medical and therapeutic interventions used to control the infections were also documented. The isolated Acanthamoeba were confirmed as belonging to the T10 genotype, an environmentally and clinically rare variety.

CONCLUSIONS

This is the first report of a cluster of postoperative T10 genotype Acanthamoeba endophthalmitis, occurring after routine cataract surgery in immunocompetent individuals. Contrary to current perceptions, a rapidly evolving infection can occur with Acanthamoeba.

The impact of water crises and climate changes on the transmission of protozoan parasites in Africa

Waterborne protozoa (WBP) are important cause of several outbreaks all over the world. The report system of WBP in Africa is weak. More than one third of African countries (21/54) reported WBP with absent reports in the remaining countries (33/54). The top reported WBP were Cryptosporidium, Giardia, FLA and Entamoeba contaminating different African water resources. Other protozoa were less documented even though it is abundant and robust. More than one protozoa were detected in contaminated African water including drinking sources, a prediction index to popular epidemics and real presence of undocumented WBP outbreaks. Risk factors in Africa were observed to be abundant and multi-factorial 'socioeconomic, governmental, pathogen in water and climate change. Climate change is an important factor impacting Africa. Increasing droughts in Africa with other extreme weather events will lead to water crises. Incidence and transmission of WBP will change, with new manifested strains/species. Recognizing future consequences of water crises in Africa are important. Governments and population unity will be needed to protect against expected raise and spread of WBP diseases and water shortages.

Morphological and molecular identification of free living amoeba isolated from hospital water in Tunisia

Free-living amoebae (FLA) are opportunistic and ubiquitous protozoa that are widely found in various environmental sources. They are known to cause serious human infections. The aim of our study was to detect FLA and Acanthamoeba spp. in hospital water circuits. Eighty-four water samples were collected over a period of 4 months (September-December 2011) from different wards of the Sfax University Hospital (surgical services, intensive care unit, operating theater, and water storage tanks). FLA were detected in 53.5 % of samples as follows: surgical services (80 %), operating theater and surgical intensive care unit (13.3 %), medical intensive care unit (0 %), water storage tanks (6.6 %). The predominant morphotype was the acanthopodial (89 %). The others morphotypes were as follows: monopodial (40 %), dactylopodial (22 %), rugosa (62 %), eruptive (24 %), fan shaped (18 %), and polypodial (18 %). Acanthamoeba was found in 40 samples (47.6 %). 64.2 % of isolates were identified as Acanthamoeba spp. by PCR, using primers to amplify a region of 18S rDNA which showed variation in the product length. Sequence analysis of five PCR products identified Acanthamoeba sp. These isolates belong to T4, T10, and T11 genotypes, and to our knowledge this is the first report of the T10 and T11 genotype in Tunisia.The occurrence of potentially pathogenic FLA in the hospital environment may represent a health risk for patients, since these organisms can cause severe opportunistic illness and also can harbor pathogenic agents. Thus, increased awareness regarding these parasites and recognition of their importance, particularly in immunocompromised patients is crucial.