Direct or DNA Extraction-Free Amplification and Quantification of Foodborne Pathogens.

The use of direct nucleic acid amplification of pathogens from food matrices has the potential to reduce time to results over DNA extraction-based approaches as well as traditional culture-based approaches. Here we describe protocols for assay design and experiments for direct amplification of foodborne pathogens in food sample matrices using loop-mediated isothermal amplification (LAMP) and polymerase chain reaction (PCR). The examples provided include the detection of Escherichia coli in milk samples and Salmonella in pork meat samples. This protocol includes relevant reagents and methods including obtaining target sequences, assay design, sample processing, and amplification. These methods, though used for specific example matrices, could be applied to many other foodborne pathogens and sample types.

Establishment of a Rapid Detection Method for Highly Virulent Klebsiella Pneumoniae Based on Multienzyme Isothermal Rapid Amplification Technology.

BACKGROUND: This study aimed to establish a method for the rapid detection of highly virulent Klebsiella pneumoniae (hvKP) by using multienzyme isothermal rapid amplification (MIRA) technology. The laboratory can quickly, accurately, and conveniently diagnose highly virulent Klebsiella pneumoniae infection. METHODS: For this study, 7 laboratory standard strains and 184 clinical isolates (including 70 strains of Klebsiella pneumoniae) were collected and screened for highly virulent Klebsiella pneumoniae based on its colony morphology, wire drawing test, and next-generation sequencing (NGS) results. Based on the nucleic acid sequence of the peg344 gene of highly virulent Klebsiella pneumoniae on GenBank (no. AP006726.1), specific conserved regions were selected to design MIRA and real-time fluorescence quantitative PCR (qPCR) specific primers and probes. The MIRA and qPCR methods were used to detect the tested strain, and the specificity, sensitivity, and clinical performance of the MIRA method for detecting hvKP were evaluated. RESULTS: In total, 21 cases of hvKP were screened from clinical isolates. The MIRA detection method utilizes specific primers and probes to transmit significant fluorescence signals at 39°C, and the detection process takes 30 minutes. The specificity test results showed that only hvKP had a specific amplification curve, while the rest of non-highly virulent Klebsiella pneumoniae (non-hvKP) had no specific amplification curve. The sensitivity test results showed that the sensitivity of MIRA for detecting hvKP is 7 × 102 CFU/mL, which is consistent with the sensitivity of the real-time fluorescence qPCR method. A simultaneous detection of 184 clinical isolates was accomplished by using MIRA and qPCR methods. Twenty-one strains of hvKP have specific amplification curves, while the remaining 163 strains of non-hvKP have no specific amplification curves. The accuracy of both methods for detecting hvKP is 100%. CONCLUSIONS: The established multienzyme isothermal rapid amplification (MIRA) has the following characteristics: a short detection time, high sensitivity, and a strong specificity, and it can be used as a powerful tool for an early diagnosis and epidemiological monitoring of hvKp.

Evolving strategies in microbe identification-a comprehensive review of biochemical, MALDI-TOF MS and molecular testing methods.

Detection and identification of microorganisms are the first steps to guide susceptibility testing and enable clinicians to confirm diseases and guide therapy. The faster the pathogen identification is determined, the quicker the appropriate treatment can be started. In the clinical microbiology laboratory, multiple methodologies can be used to identify organisms, such as traditional biochemical testing or more recent methods like MALDI TOF MS and nucleic acid detection/identification assays. Each of these techniques has advantages and limitations, and clinical laboratories need to determine which methodology is best suited to their particular setting in terms of clinical needs, availability of technical expertise and cost. This article presents a concise review of the history, utilization, advantages and limitations of the main methods used for identifying microorganisms in microbiology laboratories.

Point-of-care CRISPR-based Diagnostics with Premixed and Freeze-dried Reagents.

Molecular diagnostics by Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-based detection have high diagnostic accuracy and attributes that are suitable for use at point-of-care settings such as fast turnaround times for results, convenient simple readouts, and no requirement of complicated instruments. However, the reactions can be cumbersome to perform at the point of care due to their many components and manual handling steps. Herein, we provide a step-by-step, optimized protocol for the robust detection of disease pathogens and genetic markers with recombinase-based isothermal amplification and CRISPR-based reagents, which are premixed and then freeze-dried in easily stored and ready-to-use formats. Premixed, freeze-dried reagents can be rehydrated for immediate use and retain high amplification and detection efficiencies. We also provide a troubleshooting guide for commonly found problems upon preparing and using premixed, freeze-dried reagents for CRISPR-based diagnostics, to make the detection platform more accessible to the wider diagnostic/genetic testing communities.

Real-time qPCR coupled with high-resolution melting curve analysis for the detection of the internal transcribed spacer 1 of Angiostrongylus costaricensis.

Abdominal angiostrongyliasis (AA) is a zoonotic and severe parasitic infection caused by Angiostrongylus costaricensis. AA is currently diagnosed by the observation of A. costaricensis-compatible structures in biopsies or the detection of antibodies in serological tests. However, molecular methods targeting homologous sequences of A. costaricensis have not been designed before, and therefore, an HRM-coupled qPCR was developed to detect the internal transcribed spacer 1 (ITS1) of the parasite. The present assay successfully amplified DNA of A. costaricensis obtained from different hosts and identified slight sequence differences through the HRM analysis. The detection limit of the HRM-qPCR was 0.00036 ng/µL, 1.0 ng/µL, and 0.1 ng/µL when A. costaricensis DNA was diluted in nuclease-free water, whole blood, and sera, respectively, which highlights its potential use for cell-free DNA detection. Moreover, the reaction did not cross-amplify DNA of Angiostrongylus cantonensis, Strongyloides stercoralis, and other nematodes, thus emphasizing its specificity. Additionally, the assay tested positive in formalin-fixed paraffin embedded biopsies with visible A. costaricensis adults or eggs, but not in samples without evident parasites or a low number of larvae, which suggests that the reaction is useful for confirming the presence of the nematode in clinical samples. Finally, DNA of sera from patients with AA was evaluated with the HRM-qPCR but none tested positive, possibly due to long storage periods of the samples which could have led to cfDNA degradation. These results indicate that this assay may be useful in the confirmation of AA and its prospection for cell-free DNA detection protocols.

Criteria for second generation comparator tests in validation of novel HPV DNA tests for use in cervical cancer screening.

While HC2 and GP5+/6+ PCR-EIA were pivotal in test validation of new HPV assays, they represent the first generation of comparator tests based upon technologies that are not in widespread use anymore. In the current guideline, criteria for second-generation comparator tests are presented that include more detailed resolution of HPV genotypes. Second-generation comparator tests should preferentially target only the 12 genotypes classified as carcinogenic (IARC-group I), and show consistent non-inferior sensitivity for CIN2+ and CIN3+ and specificity for ≤CIN1 compared to one of the first-generations comparators, in at least three validation studies using benchmarks of 0.95 for relative sensitivity and 0.98 for relative specificity. Validation should take into account used storage media and other sample handling procedures. Meta-analyses were conducted to identify the assays that fulfill these stringent criteria. Four tests fulfilled the new criteria: (1) RealTime High-Risk HPV Test (Abbott), (2) Cobas-4800 HPV test (Roche Molecular System), (3) Onclarity HPV Assay (BD Diagnostics), and (4) Anyplex II HPV HR Detection (Seegene), each evaluated in three to six studies. Whereas the four assays target 14 carcinogenic genotypes, the first two identify separately HPV16 and 18, the third assay identifies five types separately and the fourth identifies all the types separately.

Development and evaluation of a rapid visual loop-mediated isothermal amplification assay for the tcdA gene in Clostridioides difficile detection.

Background: The tcdA gene codes for an important toxin produced by Clostridioides difficile (C. difficile), but there is currently no simple and cost-effective method of detecting it. This article establishes and validates a rapid and visual loop-mediated isothermal amplification (LAMP) assay for the detection of the tcdA gene. Methods: Three sets of primers were designed and optimized to amplify the tcdA gene in C. difficile using a LAMP assay. To evaluate the specificity of the LAMP assay, C. difficile VPI10463 was used as a positive control, while 26 pathogenic bacterial strains lacking the tcdA gene and distilled water were utilized as negative controls. For sensitivity analysis, the LAMP assay was compared to PCR using ten-fold serial dilutions of DNA from C. difficile VPI10463, ranging from 207 ng/µl to 0.000207 pg/µl. The tcdA gene of C.difficile was detected in 164 stool specimens using both LAMP and polymerase chain reaction (PCR). Positive and negative results were distinguished using real-time monitoring of turbidity and chromogenic reaction. Results: At a temperature of 66 °C, the target DNA was successfully amplified with a set of primers designated, and visualized within 60 min. Under the same conditions, the target DNA was not amplified with the tcdA12 primers for 26 pathogenic bacterial strains that do not carry the tcdA gene. The detection limit of LAMP was 20.700 pg/µl, which was 10 times more sensitive than that of conventional PCR. The detection rate of tcdA in 164 stool specimens using the LAMP method was 17% (28/164), significantly higher than the 10% (16/164) detection rate of the PCR method (X2 = 47, p < 0.01). Conclusion: LAMP method is an effective technique for the rapid and visual detection of the tcdA gene of C. difficile, and shows potential advantages over PCR in terms of speed, simplicity, and sensitivity. The tcdA-LAMP assay is particularly suitable for medical diagnostic environments with limited resources and is a promising diagnostic strategy for the screening and detection of C. difficile infection in populations at high risk.

A colorimetric reverse-transcription loop-mediated isothermal amplification method targeting the L452R mutation to detect the Delta variant of SARS-CoV-2.

The rapid spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has triggered global difficulties for both individuals and economies, with new variants continuing to emerge. The Delta variant of SARS-CoV-2 remains most prevalent worldwide, and it affects the efficacy of coronavirus disease 2019 (COVID-19) vaccination. Expedited testing to detect the Delta variant of SARS-CoV-2 and monitor viral transmission is necessary. This study aimed to develop and evaluate a colorimetric reverse-transcription loop-mediated isothermal amplification (RT-LAMP) technique targeting the L452R mutation in the S gene for the specific detection of the Delta variant. In the test, positivity was indicated as a color change from purple to yellow. The assay's 95% limit of detection was 57 copies per reaction for the L452R (U1355G)-specific standard plasmid. Using 126 clinical samples, our assay displayed 100% specificity, 97.06% sensitivity, and 98.41% accuracy in identifying the Delta variant of SARS-CoV-2 compared to real-time RT-PCR. To our knowledge, this is the first colorimetric RT-LAMP assay that can differentiate the Delta variant from its generic SARS-CoV-2, enabling it as an approach for studying COVID-19 demography and facilitating proper effective control measure establishment to fight against the reemerging variants of SARS-CoV-2 in the future.

Diagnostic value of the Xpert MTB/RIF assay combined with endobronchial ultrasonography with a guide sheath for peripheral nodular pulmonary tuberculosis.

BACKGROUND: The diagnosis of peripheral isolated nodular lesions that are suspected as pulmonary tuberculosis (PTB) is challenging, which are not easily accessible via conventional bronchoscopy. This study evaluated the combined use of Xpert MTB/RIF assay and endobronchial ultrasonography with a guide sheath (EBUS-GS) for detecting MTB infection in peripheral lung bands, for early detection of PTB. METHODS: The clinical data of 232 patients with suspected peripheral nodular PTB who underwent EBUS-GS between June 2020 and October 2023 were retrospectively reviewed. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and area under the curve (AUC) of acid-fast bacilli smear, culture, Xpert MTB/RIF assay, and pathological examination were calculated. To assess diagnostic accuracy, the results of the four methods were directly compared with the final clinical diagnosis. RESULTS: In total, 146 and 86 patients were clinically diagnosed with peripheral nodular PTB and non-PTB, respectively. The sensitivity, specificity, PPV, NPV, and AUC values of combined Xpert MTB/RIF assay and EBUS-GS were 47.26%, 100.0%, 100.0%, 52.76%, and 0.74; those of acid-fast bacilli smear were 8.22%, 97.67%, 85.71%, 38.53%, and 0.53; those of culture were 31.51%, 100.0%, 100.0%, 46.24%, and 0.66; and those of pathological examination were 23.97%, 97.67%, 94.59%, 43.08%, and 0.61, respectively. CONCLUSION: The diagnostic accuracy of the combined Xpert MTB/RIF assay and EBUS-GS was significantly better than that of other conventional tests. Hence, this novel technique can be routinely applied for diagnosing and managing peripheral nodular PTB.

Evaluation of molecular and bacteriological detection methods performed on the formalin-fixed paraffin-embedded biopsy samples collected from endometrial and lymph node tuberculosis suspected patients.

BACKGROUND: Endometrial Tuberculosis is one of the most common gynecological problems known to have serious implications for the quality of life like infertility. The commonly practiced histopathology solely relies on the suggestive feature of Tuberculosis (TB) with low specificity. Regarding the alternative bacteriological and molecular detection tools, little evidence was generated on their utility in the diagnosis of endometrial tuberculosis in Ethiopia. Therefore, we aim to investigate the detection rate of molecular and bacteriological detection methods on formalin-fixed paraffin-embedded biopsy samples for the diagnosis of endometrial and lymph node TB. METHODS: A retrospective cross-sectional study was conducted on 90 formalin fixed paraffin embedded biopsy samples from patients with gynecologic and lymph problems collected between 2018 and 2022 at St. Paul's Hospital Millennium Medical College, Addis Ababa, Ethiopia. SPSS version 26 was used for statistical analysis. The diagnostic performance was calculated using the histopathology method as the reference standard. Cohen's Kappa value was used to measure the level of agreement. A test with a P-value of < 0.05 was considered statistically significant. RESULTS: A total of 90 samples were analyzed in the current study. Auramine O, GeneXpert MTB/RIF assay, and Real-Time PCR tests have shown a detection rate of 32/90 (36%), 43/90 (47.8%), and 54/90 (60%) respectively (P ≤ 0.01). The sensitivity and specificity of AO were 38.1% and 95% respectively. RT PCR showed superior sensitivity followed by GeneXpert MTB/RIF assay, 70% and 58.6%. AO and molecular methods have shown a similarly low level of agreement with histopathology (Kappa value = 0.2). CONCLUSIONS: In a resource-limited setting, the selection of diagnostic tools needs careful attention. Putting the patients on anti-TB treatments based solely on histopathological findings may lead to undesired and adverse complications. Therefore, applying molecular and bacteriological detection methods along with histopathology, could help minimize inappropriate antimicrobial use.

Viral diarrheas - newer advances in diagnosis and management.

PURPOSE OF REVIEW: Viruses are the most common etiological agents of diarrhea in children. Despite rotavirus vaccine introduction, rotavirus remains as the leading cause of death globally, followed by norovirus, which represents a diagnostic challenge. Here, we describe new advances in the diagnosis and management of viral diarrheas. RECENT FINDINGS: Although immunoassays are widely used for their fast turnaround time and low cost, molecular techniques have become the most reliable diagnostic method due to their high sensitivity and capacity to analyze multiple pathogens in gastrointestinal panels. Isothermal nucleic acid amplification assays (LAMP and RPA) are promising techniques since they do not require sophisticated equipment and can be used as point-of-care testing. CRISPR/Cas nucleic acid detection systems are new diagnostic methods with great potential. Several recent published articles describe the role of human intestinal enteroids to characterize norovirus infection, to test new drugs, and for vaccine development. The interaction between the human gut microbiota and gastrointestinal viral infections has been extensively reviewed and offers some innovative mechanisms for therapeutic and preventive measures. SUMMARY: Although important advances have been made, more research is needed to address remaining challenges and further improve diagnostic capabilities and better management strategies for this critical infectious disease.

Development of a highly specific LAMP assay for detection of Sarcocystis tenella and Sarcocystis gigantea in sheep.

Sarcocystis infection in sheep has caused significant economic losses in the livestock industry, and the genetic similarity among Sarcocystis species highlights the need for precise diagnostic methods in sheep. This study developed a loop-mediated isothermal amplification (LAMP) method targeting COX-1 and 28S rRNA genes to detect Sarcocystis tenella and Sarcocystis gigantea, respectively. The LAMP method exhibited high specificity, selectively amplifying target DNA sequences without cross-reactivity with closely related protozoa, such as Toxoplasma gondii and Neospora caninum. Detection limits were determined as 3 × 105 copies/L for S. tenella and 6 × 104 copies/L for S. gigantea, enabling sensitive identification of low-level infections. Comparative analysis with conventional PCR on sheep cardiac tissues demonstrated a higher LAMP detection rate (80.0% vs 66.7%). In conclusion, the LAMP method offers superior sensitivity to conventional PCR, allows visual confirmation of results, and provides a rapid diagnostic tool for identifying S. tenella and S. gigantea infection in sheep. However, due to the limitation of sample availability, we were unable to assess all Sarcocystis species that use sheep as intermediate hosts, which warrants further research.

Comparative analysis of metagenomic and targeted next-generation sequencing for pathogens diagnosis in bronchoalveolar lavage fluid specimens.

Background: Although the emerging NGS-based assays, metagenomic next-generation sequencing (mNGS) and targeted next-generation sequencing (tNGS), have been extensively utilized for the identification of pathogens in pulmonary infections, there have been limited studies systematically evaluating differences in the efficacy of mNGS and multiplex PCR-based tNGS in bronchoalveolar lavage fluid (BALF) specimens. Methods: In this study, 85 suspected infectious BALF specimens were collected. Parallel mNGS and tNGS workflows to each sample were performed; then, we comparatively compared their consistency in detecting pathogens. The differential results for clinically key pathogens were confirmed using PCR. Results: The microbial detection rates of BALF specimens by the mNGS and tNGS workflows were 95.18% (79/83) and 92.77% (77/83), respectively, with no significant difference. mNGS identified 55 different microorganisms, whereas tNGS detected 49 pathogens. The comparative analysis of mNGS and tNGS revealed that 86.75% (72/83) of the specimens were complete or partial concordance. Particularly, mNGS and tNGS differed significantly in detection rates for some of the human herpesviruses only, including Human gammaherpesvirus 4 (P<0.001), Human betaherpesvirus 7 (P<0.001), Human betaherpesvirus 5 (P<0.05) and Human betaherpesvirus 6 (P<0.01), in which tNGS always had higher detection rates. Orthogonal testing of clinically critical pathogens showed a total coincidence rate of 50% for mNGS and PCR, as well as for tNGS and PCR. Conclusions: Overall, the performance of mNGS and multiplex PCR-based tNGS assays was similar for bacteria and fungi, and tNGS may be superior to mNGS for the detection of DNA viruses. No significant differences were seen between the two NGS assays compared to PCR.

Synergy of Xpert (MTB/RIF) and Line probe assay for detection of rifampicin resistant strains of Mycobacterium tuberculosis.

INTRODUCTION: Early diagnosis and successful treatment of drug-resistant tuberculosis (TB) demands rapid, precise, and consistent diagnostic methods to minimise the development of resistance. Therefore, this comparative study was designed to evaluate the diagnostic performance of Xpert (MTB/RIF) and Line probe assay (LPA) for detecting drug-resistant TB. METHODOLOGY: This study comprised 389 (279 pulmonary and 110 extrapulmonary) samples from patients suspected of having TB. All samples were subjected to Xpert (MTB/RIF), LPA, solid culture, and drug-susceptibility testing. Out of 320 samples, only 180 culture (gold standard) positive were included in the final evaluation. The diagnostic characteristics for methods used were determined by calculating diagnostic sensitivity, specificity, and predictive values. The agreement between all methods was determined by calculating the kappa coefficient. RESULTS: The sensitivity and specificity for Xpert (MTB/RIF) for detecting TB were 88.5% and 96.4%, respectively, against the solid culture. On the other hand, LPA showed sensitivity and specificity at 94.3% and 100%, respectively. Xpert (MTB/RIF) showed moderate agreement (kappa 0.65, p < 0.01) - (73.3% sensitivity; 97.6% specificity) for the detection of rifampicin resistance. However, LPA achieved better diagnostic accuracy (kappa 0.80, p < 0.01) - (84.6% sensitivity; 98.4% specificity) against drug-resistant TB. CONCLUSIONS: Xpert (MTB/RIF) and LPA have outstanding diagnostic sensitivity and specificity against RIF resistance with a shorter turnaround time, which could result in a substantial therapeutic outcome. Our findings showed LPA superiority over Xpert (MTB/RIF) for drug resistance. However, due to operational challenges, the requirement of technical expertise and infrastructure issues, LPA cannot be used as point-of-care testing in resource-limited countries.

An at-home and electro-free COVID-19 rapid test based on colorimetric RT-LAMP.

INTRODUCTION: In the fight against virus-caused pandemics like COVID-19, diagnostic tests based on RT-qPCR are essential, but they are sometimes limited by their dependence on expensive, specialized equipment and skilled personnel. Consequently, an alternative nucleic acid detection technique that overcomes these restrictions, called loop-mediated isothermal amplification following reverse transcription (RT-LAMP), has been broadly investigated. Nevertheless, the developed RT-LAMP assays for SARS-CoV-2 detection still require laboratory devices and electrical power, limiting their widespread use as rapid home tests. This work developed a flexible RT-LAMP assay that gets beyond the drawbacks of the available isothermal LAMP-based SARS-CoV-2 detection, establishing a simple and effective at-home diagnostic tool for COVID-19. METHODOLOGY: A multiplex direct RT-LAMP assay, modified from the previously developed test was applied to simultaneously identify the two genes of SARS-CoV-2. We used a colorimetric readout, lyophilized reagents, and benchmarked an electro-free and micropipette-free method that enables sensitive and specific detection of SARS-CoV-2 in home settings. RESULTS: Forty-one nasopharyngeal swab samples were tested using the developed home-testing RT-LAMP (HT-LAMP) assay, showing 100% agreement with the RT-qPCR results. CONCLUSIONS: This is the first electrically independent RT-LAMP assay successfully developed for SARS-CoV-2 detection in a home setting. Our HT-LAMP assay is thus an important development for diagnosing COVID-19 or any other infectious pandemic on a population scale.

An alternative colorimetric RT-LAMP assay for the rapid detection of SARS-CoV-2: development and validation in Thailand.

INTRODUCTION: COVID-19, an emerging infectious disease caused by SARS-CoV-2, continues to be a global public health threat. The development of a colorimetric reverse transcription loop-mediated isothermal amplification (RT-LAMP) can extend the availability of simple, reliable molecular tests for the rapid detection of COVID-19. METHODOLOGY: The RT-LAMP assay was developed using a new primer set targeting a portion of SARS-CoV-2 orf8. The method was validated at 63 ºC for 60 minutes with naked-eye visualization of the color change. The clinical performance was compared to a real-time reverse transcription-polymerase chain reaction (rtRT-PCR) using 273 RNA samples extracted from nasopharyngeal swab specimens. RESULTS: The developed RT-LAMP was specific to SARS-CoV-2 with a limit of detection at 15 RNA copies per reaction. The assay demonstrated diagnostic accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of 90.48% (95% CI: 86.36-93.68%), 87.00% (95% CI: 81.53-91.33%), 100% (95% CI: 95.07-100%), 100% (95% CI: not available), and 73.74% (95% CI: 66.22-80.07%), respectively, compared to the rtRT-PCR. The greatest sensitivity of 98.03% (95% CI: 94.34-99.59%) was demonstrated in samples with the cycle threshold (Ct) values < 30 cycles. CONCLUSIONS: The RT-LAMP method in this study showed good performance. The assay can increase the scope of laboratory testing for rapidly detecting SARS-CoV-2 in Thailand. Due to a decrease in COVID-19 cases, its application is beneficial when commercial alternatives are unavailable.

A simple color absorption analysis of colorimetric loop-mediated isothermal amplification for detection of Raillietina spp. in clinical samples using a 3D-printed tube holder coupled with a smartphone camera and notebook screen.

A simple method has been developed for semi-quantitative analysis of the colorimetric output of loop-mediated isothermal amplification (LAMP) using a 3D-printed tube holder with a smartphone and notebook for the detection of Raillietina, which is the cause of Raillietiniasis affecting free-range chicken farming. In this method, a light is directed from a notebook screen to the LAMP products in the tube holder and the color absorption of the LAMP products is measured by using the appropriate smartphone application. It was found that the malachite green dye-coupled LAMP (MaG-LAMP) assay showed the highest sensitivity and specificity for detecting Raillietina without any cross-reaction with other related parasites and hosts. The limit of detection was 10 fg/µL of DNA. A total of 60 fecal samples were infectively confirmed by microscopic examination and the results of microscopy compared with those of MaG-LAMP and triplex PCR assays. Microscopy and MaG-LAMP based on the color absorption demonstrated high agreement in Raillietina detection with kappa = 1. Rapid, simple, cost-effective, and easy interpretation of colorimetric LAMP assays and their high sensitivity make them superior to PCR and morphological investigation, demonstrating the feasibility of this assay in point-of-care screening to support farm management and solve chicken health problems. Our study presents is an alternative diagnostic method using semi-quantitative analysis of colorimetric LAMP based on the differing solution color absorptions between positive and negative reactions for infectious disease diagnosis.

Molecular Diagnosis of Human Cutaneous Leishmaniasis and Identification of the Causative Leishmania Species in Iran: A Narrative Review

Cutaneous leishmaniasis (CL) is a common form of leishmaniasis in underdeveloped countries. Although CL tends to be self-limiting, it can cause significant scars and may progress to more severe manifestations. Additionally, Leishmania species vary in susceptibility to the available treatments. The selection of treatment and clinical outcome of CL depend on the accurate determination of the Leishmania species. This mini-review aims to provide an overview of the molecular diagnosis techniques such as PCR-based assays, nucleic acid sequence-based amplification, and loop-mediated isothermal amplification utilized in the identification of Leishmania species in Iran.

Establishment of LAMP-CRISPR/Cas12a for rapid detection of Escherichia coli O157:H7 and one-pot detection.

Escherichia coli O157:H7 is a pathogenic serotype of Escherichia coli. Consumption of food contaminated with E. coli O157:H7 could cause a range of diseases. Therefore, it is of great importance to establish rapid and accurate detection methods for E. coli O157:H7 in food. In this study, based on LAMP and combined with the CRISPR/cas12a system, a sensitive and specific rapid detection method for E. coli O157:H7 was established, and One-Pot detection method was also constructed. The sensitivity of this method could stably reach 9.2 × 10° CFU/mL in pure culture, and the whole reaction can be completed within 1 h. In milk, E. coli O157:H7 with an initial contamination of 7.4 × 10° CFU/mL only needed to be cultured for 3 h to be detected. The test results can be judged by the fluorescence curve or by visual observation under a UV lamp, eliminating instrument limitations and One-Pot detection can effectively prevent the problem of false positives. In a word, the LAMP-CRISPR/cas12a system is a highly sensitive and convenient method for detecting E. coli O157:H7.