Rapid and sensitive diagnosis of Acanthamoeba keratitis by loop-mediated isothermal amplification

Ultrasensitive and rapid diagnostic tool for detection of Acanthamoeba castellanii

Acanthamoeba keratitis is a devastating infectious disease of the cornea caused by an opportunistic amoeba, Acanthamoeba castellanii. It is poorly recognized, and diagnostic delays can lead to irreversible damage to the vision. The gold standard for diagnosis has been a sample culture that lasts approximately 2 weeks. Nevertheless, the essence of time has led to the need for an accurate and fast technique to detect A. castellanii from a sample. We developed both traditional and quantitative real-time-PCR-based methods to detect A. castellanii in less than 3 hours and with the sensitivity of one amoeba. Diagnostic laboratories can select the best-suited method for their purposes from 2 comparable methods. The correct treatment can be initiated from the emergency room when the diagnosis has been made quickly within a few hours, hence saving the patient from long-term complications.

Diagnosis of Acanthamoeba Keratitis: Past, Present and Future

Acanthamoeba keratitis (AK) is a painful and sight-threatening parasitic corneal infection. In recent years, the incidence of AK has increased. Timely and accurate diagnosis is crucial during the management of AK, as delayed diagnosis often results in poor clinical outcomes. Currently, AK diagnosis is primarily achieved through a combination of clinical suspicion, microbiological investigations and corneal imaging. Historically, corneal scraping for microbiological culture has been considered to be the gold standard. Despite its technical ease, accessibility and cost-effectiveness, the long diagnostic turnaround time and variably low sensitivity of microbiological culture limit its use as a sole diagnostic test for AK in clinical practice. In this review, we aim to provide a comprehensive overview of the diagnostic modalities that are currently used to diagnose AK, including microscopy with staining, culture, corneal biopsy, in vivo confocal microscopy, polymerase chain reaction and anterior segment optical coherence tomography. We also highlight emerging techniques, such as next-generation sequencing and artificial intelligence-assisted models, which have the potential to transform the diagnostic landscape of AK.

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.

Diagnostic armamentarium of infectious keratitis: A comprehensive review

Infectious keratitis (IK) represents the leading cause of corneal blindness worldwide, particularly in developing countries. A good outcome of IK is contingent upon timely and accurate diagnosis followed by appropriate interventions. Currently, IK is primarily diagnosed on clinical grounds supplemented by microbiological investigations such as microscopic examination with stains, and culture and sensitivity testing. Although this is the most widely accepted practice adopted in most regions, such an approach is challenged by several factors, including indistinguishable clinical features shared among different causative organisms, polymicrobial infection, long diagnostic turnaround time, and variably low culture positivity rate. In this review, we aim to provide a comprehensive overview of the current diagnostic armamentarium of IK, encompassing conventional microbiological investigations, molecular diagnostics (including polymerase chain reaction and mass spectrometry), and imaging modalities (including anterior segment optical coherence tomography and in vivo confocal microscopy). We also highlight the potential roles of emerging technologies such as next-generation sequencing, artificial intelligence-assisted platforms. and tele-medicine in shaping the future diagnostic landscape of IK.

Efficient nested-PCR-based method development for detection and genotype identification of Acanthamoeba from a small volume of aquatic environmental sample

Acanthamoeba spp. are opportunistic human pathogens that cause granulomatous amoebic encephalitis and keratitis, and their accurate detection and enumeration in environmental samples is a challenge. In addition, information regarding the genotyping of Acanthamoeba spp. using various PCR methods is equally critical. Therefore, considering the diverse niches of habitats, it is necessary to develop an even more efficient genotyping method for Acanthamoeba spp. detection. This study improved the sensitivity of detection to avoid underestimation of Acanthamoeba spp. occurrence in aquatic environmental samples, and to accurately define the pathogenic risk by developing an efficient PCR method. In this study, a new nested genotyping method was established and compared with various PCR-based methods using in silico, lab, and empirical tests. The in silico test showed that many PCR-based methods could not successfully align specific genotypes of Acanthamoeba, except for the newly designed nested PCR and real-time PCR method. Furthermore, 52 water samples from rivers, reservoirs, and a river basin in Taiwan were analysed by six different PCR methods and compared for genotyping and detection efficiency of Acanthamoeba. The newly developed nested-PCR-based method of genotyping was found to be significantly sensitive as it could effectively detect the occurrence of Acanthamoeba spp., which was underestimated by the JDP-PCR method. Additionally, the present results are consistent with previous studies indicating that the high prevalence of Acanthamoeba in the aquatic environment of Taiwan is attributed to the commonly found T4 genotype. Ultimately, we report the development of a small volume procedure, which is a combination of recent genotyping PCR and conventional real-time PCR for enumeration of aquatic Acanthamoeba and acquirement of biologically meaningful genotyping information. We anticipate that the newly developed detection method will contribute to the precise estimation, evaluation, and reduction of the contamination risk of pathogenic Acanthamoeba spp., which is regularly found in the water resources utilised for domestic purposes.

The Autofluorescence Patterns of Acanthamoeba castellanii, Pseudomonas aeruginosa and Staphylococcus aureus: Effects of Antibiotics and Tetracaine

Acanthamoeba Keratitis (AK) can lead to substantial vision loss and morbidity among contact lens wearers. Misdiagnosis or delayed diagnosis is a major factor contributing to poor outcomes of AK. This study aimed to assess the effect of two antibiotics and one anaesthetic drug used in the diagnosis and nonspecific management of keratitis on the autofluorescence patterns of Acanthamoeba and two common bacteria that may also cause keratitis. Acanthamoeba castellanii ATCC 30868, Pseudomonas aeruginosa ATCC 9027, and Staphylococcus aureus ATCC 6538 were grown then diluted in either PBS (bacteria) or ¼ strength Ringer’s solution (Acanthamoeba) to give final concentrations of 0.1 OD at 660 nm or 10⁴ cells/mL. Cells were then treated with ciprofloxacin, tetracycline, tetracaine, or no treatment (naïve). Excitation–emission matrices (EEMs) were collected for each sample with excitation at 270–500 nm with increments in 5 nm steps and emission at 280–700 nm at 2 nm steps using a Fluoromax-4 spectrometer. The data were analysed using MATLAB software to produce smoothed color-coded images of the samples tested. Acanthamoeba exhibited a distinctive fluorescence pattern compared to bacteria. The addition of antibiotics and anaesthetic had variable effects on autofluorescence. Tetracaine altered the fluorescence of all three microorganisms, whereas tetracycline did not show any effect on the fluorescence. Ciprofloxacin produced changes to the fluorescence pattern for the bacteria, but not Acanthamoeba. Fluorescence spectroscopy was able to differentiate Acanthamoeba from P. aeruginosa and S. aureus in vitro. There is a need for further assessment of the fluorescence pattern for different strains of Acanthamoeba and bacteria. Additionally, analysis of the effects of anti-amoebic drugs on the fluorescence pattern of Acanthamoeba and bacteria would be prudent before in vivo testing of the fluorescence diagnostic approach in the animal models.

Single Administration of a Biodegradable, Separable Microneedle Can Substitute for Repeated Application of Eyedrops in the Treatment of Infectious Keratitis

Infectious keratitis is mainly treated with topical antibiotics. To achieve and maintain the required therapeutic concentration in the cornea where the tear fluid continuously rinses the surface, the antibiotics must be frequently applied, even while the patient is sleeping, and oral medication is sometimes required. However, the inevitably poor compliance and avascular nature of the cornea decrease drug bioavailability. In this study, a single microneedle (MN) is injected into the cornea to substitute for the repeated application of eyedrops in the treatment of infectious keratitis. After comparing the mechanical integrity and drug release profiles of three different drug-tips, the drug-tip with the "high" drug concentration that releases 12.5 ng drug within 3 days is applied to a cornea to evaluate the transferability and in vivo drug release. In the treatment of infectious keratitis with repeated application of eyedrops for six consecutive days, a single MN injection is substituted for the initial 3 days of eyedrop applications. The progression remains similarly attenuated after 3 days without eyedrops, and comparable efficacy is achieved on day 6 when combined with delayed eyedrop treatment from day 3. Thus, the single administration of a biodegradable MN can substitute for the repeated application of eyedrops in the treatment of infectious keratitis.

Establishment of an Acanthamoeba keratitis mouse model confirmed by amoebic DNA amplification

Acanthamoeba castellanii, the causative agent of Acanthamoeba keratitis (AK), occurs mainly in contact lens users with poor eye hygiene. The findings of many in vitro studies of AK, as well as the testing of therapeutic drugs, need validation in in vivo experiments. BALB/c mice were used in this study to establish in vivo AK model. A. castellanii cell suspensions (equal mixtures of trophozoites and cysts) were loaded onto 2-mm contact lens pieces and inserted into mouse eyes that were scratched using an ophthalmic surgical blade under anesthesia and the eyelids of the mice were sutured. The AK signs were grossly observed and PCR was performed using P-FLA primers to amplify the Acanthamoeba 18S-rRNA gene from mouse ocular tissue. The experimental AK mouse model was characterized by typical hazy blurring and melting of the mouse cornea established on day 1 post-inoculation. AK was induced with at least 0.3 × 10⁵ A. castellanii cells (optimal number, 5 × 10⁴), and the infection persisted for two months. The PCR products amplified from the extracted mouse eye DNA confirmed the development of Acanthamoeba-induced keratitis during the infection periods. In conclusion, the present AK mouse model may serve as an important in vivo model for the development of various therapeutic drugs against AK.

Acanthamoeba keratitis in a mouse model using a novel approach

CONTEXT

Acanthamoeba is increasingly implicated in causing keratitis in patients wearing contact lens or ocular trauma and has a poor prognosis. Establishment of an animal model is critical to study the disease pathology, pathogenesis and to evaluate anti-amoebic drugs. Some studies have used contact lenses to establish Acanthamoeba keratitis (AK) in a mouse model, which is expensive and not very successful as lenses get dislodged.

OBJECTIVE

To assess the feasibility of using parafilm (Bemis Company Inc., USA) as an alternative to contact lens for the establishment of AK in the mouse model.

METHODS

Thirty-six Balb/c mice in three groups of six mice each for two strains of Acanthamoeba were used to induce AK. Three experimental approaches used were; i) Acanthamoeba impregnated contact lens, ii) Acanthamoeba impregnated parafilm and iii) scratching followed by inoculation of Acanthamoeba suspension. In all three models, tarsorrhaphy was performed. Infection was evaluated by clinical examination and also through microscopic examination of corneal scrapings and corneal sections.

RESULTS

AK model was successfully established with parafilm whereas only one mouse developed AK with the use of contact lens and none with scratching and Acanthamoeba inoculation.

CONCLUSION

The use of parafilm is convenient, reliable and cheaper and can be considered an alternative to contact lenses to induce AK in a mouse model.

WITHDRAWN: Acanthamoeba keratitis in a mouse model using a novel approach

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Intracorneal injection of a detachable hybrid microneedle for sustained drug delivery

There are increasing demands for long-term and controlled corneal drug delivery to treat various ocular diseases. Although biodegradable ocular inserts or contact lenses have been developed, the invasiveness and inefficiency of the approaches still need to be improved. Microneedle (MN) technology can deliver therapeutic molecules to the eye in a minimally invasive manner. However, the current ocular MN technology is limited to either short-term corneal drug delivery or retinal drug delivery by suprachoroidal injection. For long-term and minimally invasive corneal drug delivery, we have developed a detachable biodegradable MN that can be delivered to the inside of the cornea for sustained drug release. The detachable and biodegradable MN is a hybrid MN consisting of a drug-loaded biodegradable tip and a supporting base. The hybrid MN can be applied to the cornea by impact insertion, and it leaves only the drug-loaded biodegradable tip within the corneal tissue so that it can release the drug for a certain period. By concentration-controlled molding, the dimension of drug-loaded MN tips was precisely controlled and their detachability was optimized. The detachable tip and a supporting base were assembled to form a hybrid MN by pressure-assisted transfer molding. We carefully optimized the dimension of the drug-tip, injection dwell time, and insertion depth to achieve effective intracorneal injection of the drug-tip. The detachable hybrid MN was applied to an Acanthamoeba keratitis model wherein a biodegradable drug-tip was successfully delivered to the inside of the mouse cornea in vivo. Follow-up of the MN-treated cases for 7 days confirmed the therapeutic efficacy of the detachable biodegradable MN tips. STATEMENT OF SIGNIFICANCE: For the treatment of infectious diseases in the cornea, such as keratitis, eye drops need to be applied topically every hour for a couple of days. This is extremely uncomfortable, and poor compliance to such tightly scheduled drug administration can result in permanent scar formation in the cornea. In this work, we demonstrate a simple and rapid injection of biodegradable microneedle tips in the corneal tissue wherein the tips can deliver antibacterial drugs for 4 days to treat keratitis. Unlike other patch-style microneedle technologies, this approach allows for insertion depth-controlled and highly localized injection of detachable individual microneedle tips to the diseased tissue for sustained drug delivery. This overcomes the limitations of patch-style microneedles such as short-term drug delivery and unnecessary blockage of tissue.

Acanthamoeba keratitis: An emerging disease among microbial keratitis in the Cap Bon region of Tunisia

INTRODUCTION

The aim of this study was to describe the prevalence of AK among microbial keratitis as well as their clinical features and to compare their risk factors to those of other infectious keratitis, over the last five years in a referral center in the region of Cap Bon, Tunisia, North Africa.

METHODS

A retrospective review of the charts of 230 patients (230 eyes) diagnosed with presumed infectious keratitis between January 2011 and December 2016 at the department of ophthalmology of the university hospital of Nabeul in Tunisia. After a detailed ocular examination using standard technique, corneal scrapes were performed under aseptic conditions from each ulcer. Plates were incubated at 30 °C and screened daily for Amoeba. The treatment was adjusted according to the results of microbiological findings and the response of initial treatment. The mean follow up was 11.4 months (1 month-26 months).

RESULTS

A total of 230 corneas were scraped. The prevalence of Acanthamoeba keratitis was 6% (14 cases of 230). All cases of Acanthamoeba keratitis with a history of contact lenses were diagnosed thanks to the test of Contact lenses, their cases or their storage solution, while their corneal scrapings were negative. The corneal scraping was positive for Acanthamoeba only in 4 cases of 14. Acanthamoeba was identified more in young patients (92.8%). Significantly, more patients (54 of 74; 73%) with fungal keratitis and Acanthamoeba keratitis (11 of14; 78.6%) were rural population The most cases of Acanthamoeba keratitis (10 of 14; 71.4%) used contact lenses. Ocular injury was identified in 4 cases of 14 AK (28,5%). Coexistent ocular disease was seen in seven cases of 14 (50%). Of the 230 microbial keratitis, an early diagnosis (≤30 days) was done in 200 cases (86.95%), while a late diagnosis (≥30 days) was made in 30 cases (13%). In AK, most cases (11 of 14; 78,5%) were diagnosed with a delay of more than 30 days. Slit-lamp examination showed stromal infiltrate in 12 cases (85,7%), hypopion in 2 cases (14,3%), immunitary ring in 2 cases (14,3%) and radial keratoneuritis in one case (7,1%).

CONCLUSION

Contact lenses were identified as the main risk factor of Acanthamoeba keratitis in our study. The diagnosis of AK should be considered in case of atypical keratitis especially among CL wearers in the rural regions of CapBon where the rules of hygiene are not respected.

Associated factors, diagnosis and management of Acanthamoeba keratitis in a referral Center in Southern China

BACKGROUND

To analyse the associated factors, diagnosis, clinical manifestations and therapeutic effects of Acanthamoeba keratitis at a tertiary ophthalmic centre in Southern China.

METHODS

A retrospective clinical study was performed in fifteen patients who were admitted to Zhongshan Ophthalmic Centre (ZOC) from January 2004 to December 2014. The patients' pathogenesis-associated factors were analysed, and preoperative diagnoses were determined using corneal scraping cultures and/or confocal microscopy followed. All diagnoses were confirmed by postoperative pathological examinations. At follow-up, best-corrected visual acuity (BCVA), the recurrence rate and graft transparency were evaluated to assess therapeutic effects.

RESULTS

The main pathogenic factors observed in the fifteen patients were a history of injury or a foreign body entering the eyes (12 cases). In all, Acanthamoeba keratitis was preoperatively diagnosed in 5 cases using corneal scraping cultures or confocal microscopy. Ocular symptoms included redness, photophobia, tearing, and blurred vision. Penetrating keratoplasty was performed in thirteen patients, and postoperative pathological examinations were performed to confirm these diagnoses. The logarithm of the minimum angle of resolution (logMAR) of visual acuity was significantly improved after keratoplasty (p < 0.01). No recurrence was observed, and approximately 90% of the corneal grafts were found to be transparent during the follow-up period.

CONCLUSIONS

Corneal trauma may be the main pathogenic factor that causes Acanthamoeba keratitis in southern China. Corneal scraping combined with confocal microscopy was helpful for achieving a correct diagnosis. Early keratoplasty combined with amoebicidal therapy is an effective treatment strategy in Acanthamoeba keratitis.

A DNA dot hybridization model for molecular diagnosis of parasitic keratitis

Purpose

Developing a DNA dot hybridization model for diagnosing parasitic keratitis.

Methods

Newly designed oligonucleotide probes for detecting Acanthamoeba and microsporidia were tested with target reference strains of Acanthamoeba (n = 20) and microsporidia (n = 3), and non-target microorganisms, including bacteria (n = 20) and fungi (n = 20). These probes, which had passed the preliminary tests, were then assembled as a parasite dot hybridization (PDH) model for assessing 33 clinical samples from patients with clinically suspected Acanthamoeba and microsporidia keratitis, including eight positives for Acanthamoeba, 13 positives for microsporidia, and 12 negatives for both pathogens.

Results

Two probes for detecting Acanthamoeba and two for detecting microsporidia passed the tests using target and non-target strains and then were assembled in the PDH model. For clinical samples, one Acanthamoeba-positive sample (proved with pathology) was falsely negative according to the PDH assay. The sensitivity and specificity of the PDH assay for diagnosing Acanthamoeba keratitis were 87.5% and 100%, respectively, while the sensitivity and specificity for diagnosing microsporidia keratitis were 100%. The infectious agent of all clinical samples of microsporidia keratitis was identified as Vittaforma corneae with DNA sequencing, while those of Acanthamoeba keratitis were caused by four species of Acanthamoeba, with Acanthamoeba castellanii found in four samples (50%, 4/8).

Conclusions

The PDH model has the potential to be a molecular assay for diagnosing Acanthamoeba and microsporidia keratitis. However, a prospective clinical study might be needed before the model is adopted in routine clinical practice.

Detection of Acanthamoeba spp. in water samples collected from natural water reservoirs, sewages, and pharmaceutical factory drains using LAMP and PCR in China

Various species of amoebas belonging to the genus Acanthamoeba are widely distributed in many parts of the world. Some strains of these protozoans may exist as parasites and pose risks to human health as causative agents of serious human diseases. Currently in China there is a lack of information about the distribution of Acanthamoeba strains in the environment. Accordingly, 261 environmental water samples taken from rivers, sewage, and pharmaceutical factory drains were collected in Qinghai Province, China. The material was filtered and then analysed with both LAMP and PCR assays. Of the samples examined, Acanthamoeba DNA was found in 32 (14.68%) samples with the use of LAMP; in 13 of these samples, DNA from this amoeba was also detected using PCR. Sequencing of selected positive samples confirmed that the PCR products were fragments of the Acanthamoeba 18S rRNA gene and that isolates represent the T4 genotype, known as the most common strain related to AK cases. The results indicate that surface water, as well as water taken from sewage and pharmaceutical drains, may be a source of acanthamoebic strains potentially pathogenic for humans in China. It has been also demonstrated that LAMP assays is more sensitive than PCR and can be regarded as useful tool for screening the environment for Acanthamoeba spp.

Evaluation of loop-mediated isothermal amplification assay for rapid diagnosis of Acanthamoeba keratitis

BACKGROUND

The clinical features of Acanthamoeba keratitis (AK) are non-specific and closely resemble bacterial, viral and fungal keratitis.

MATERIALS AND METHODS

We compared loop-mediated isothermal amplification (LAMP) with microscopy, non-nutrient agar (NNA) culture and polymerase chain reaction (PCR) in clinical suspects of AK.

RESULTS

Of 52 clinical samples (42 AK suspects and 10 proven bacterial, viral or fungal keratitis), 3 were positive by direct microscopy (sensitivity 60%, confidence interval [CI]: 17%-92.7%), and 5 by NNA culture, 18S rDNA PCR and LAMP (sensitivity 100%, CI: 46.3%-100%). The limit of detection of Acanthamoeba DNA was 1 pg/μl by both LAMP and PCR.

CONCLUSION

PCR and LAMP assays targeting 18S rDNA gene were found particularly suitable for a rapid and accurate diagnosis of AK. LAMP assay takes 2-3 h lesser than PCR, and thus offers a rapid, highly sensitive and specific, simple and affordable diagnostic modality for patients suspected of AK, especially in resource limited settings.

Detection methods for milk pathogenic bacteria by loop-mediated isothermal amplification

Milk is a common food, which is consumed all over the world. It is an important source of calcium. Meanwhile, it provides abundant protein, minerals and vitamins. However, pathogenic bacteria which exist in milk not only causes nutrition loss, but also produces toxins which may cause diarrhea, food poisoning, and even death. In order to control the microbial level of raw milk and eliminate the contamination of materials, this assay applied loop-mediated isothermal amplification to explore a new way to detect enterotoxigenic Escherichia coli (ETEC) in raw milk. The best reaction condition in detecting ETEC from raw milk was confirmed to be: 0.016 μM each of forward outer primer (primer F3) and backward outer primer (primer B3), 0.128 μM each of forward inner primer (primer FIP) and backward inner primer (primer BIP), 0.45 μM deoxy-ribonucleoside triphosphate (dNTPs), 2IU Bst DNA polymerase large fragment and template DNA were incubated at 63°C for 60 min. LAMP was proved to be specific, rapid and sensitive in detecting pathogenic bacteria which exist in milk.

Acanthamoeba keratitis: improving the Scottish diagnostic service for the rapid molecular detection of Acanthamoeba species

Acanthamoeba species are responsible for causing the potentially sight-threatening condition, Acanthamoeba keratitis, which is commonly associated with contact lens use. In this report, we highlight the challenges faced using conventional laboratory identification methods to identify this often under-reported pathogen, and discuss the reasons for introducing the first national service in Scotland for the rapid and sensitive molecular identification of Acanthamoeba species. By comparing culture and molecular testing data from a total of 63 patients (n = 80 samples) throughout Scotland presenting with ocular eye disease, we describe the improvement in detection rates where an additional four positive cases were identified using a molecular assay versus culture. The testing of a further ten patients by confocal imaging is also presented. This report emphasizes the importance of continuing to improve clinical laboratory services to ensure a prompt, correct diagnosis and better prognosis, in addition to raising awareness of this potentially debilitating opportunistic pathogen.

Molecular inversion probe: a new tool for highly specific detection of plant pathogens

Highly specific detection methods, capable of reliably identifying plant pathogens are crucial in plant disease management strategies to reduce losses in agriculture by preventing the spread of diseases. We describe a novel molecular inversion probe (MIP) assay that can be potentially developed into a robust multiplex platform to detect and identify plant pathogens. A MIP has been designed for the plant pathogenic fungus Fusarium oxysporum f.sp. conglutinans and the proof of concept for the efficiency of this technology is provided. We demonstrate that this methodology can detect as little as 2.5 ng of pathogen DNA and is highly specific, being able to accurately differentiate Fusarium oxysporum f.sp. conglutinans from other fungal pathogens such as Botrytis cinerea and even pathogens of the same species such as Fusarium oxysporum f.sp. lycopersici. The MIP assay was able to detect the presence of the pathogen in infected Arabidopsis thaliana plants as soon as the tissues contained minimal amounts of pathogen. MIP methods are intrinsically highly multiplexable and future development of specific MIPs could lead to the establishment of a diagnostic method that could potentially screen infected plants for hundreds of pathogens in a single assay.