Antibacterial activity of Mangifera indica seed extracts combined with common antibiotics against multidrug-resistant Pseudomonas aeruginosa and Acinetobacter baumannii isolates

In this project, we employed ethanolic (EMI) and aqueous (AMI) extracts of mango (Mangifera indica L., Anacardiaceae) fruit seeds as a modulator of antibiotic resistance against multidrug-resistant (MDR) Pseudomonas aeruginosa and Acinetobacter baumannii to evaluate natural compounds isolated from by-products or waste of edible plants. We also investigated the effect of these extracts alone and in combination with standard classes of antibiotics in the desired strains. M. indica seeds were processed and exploited using ethanol and water. The minimum inhibitory concentrations (MICs) of clinical isolates were examined against EMI and AMI extracts, followed by seven antibiotics of ceftazidime, ciprofloxacin, penicillin, amikacin, meropenem, ampicillin, and colistin. The checkerboard method evaluated the synergistic action between mango kernel extract (EMI) and seven antibiotics. EMI extract significantly revealed antimicrobial properties against MDR A. baumannii and P. aeruginosa with synergistic effects with the applied antibiotics. The considerable antibacterial efficacy of ethanolic extract of M. indica seeds can have great curative value as antibacterial drugs against infections caused by MDR P.aeruginosa and A. baumannii

A Comparative Study on Visual Detection of <i>Mycobacterium tuberculosis</i> by Closed Tube Loop-Mediated Isothermal Amplification: Shedding Light on the Use of Eriochrome Black T

Loop-mediated isothermal amplification is a promising candidate for the rapid detection of Mycobacterium tuberculosis. However, the high potential for carry-over contamination is the main obstacle to its routine use. Here, a closed tube LAMP was intended for the visual detection of Mtb to compare turbidimetric and two more favorable colorimetric methods using calcein and hydroxy naphthol blue (HNB). Additionally, a less studied dye (i.e., eriochrome black T (EBT)) was optimized in detail in the reaction for the first time. Mtb purified DNA and 30 clinical specimens were used to respectively determine the analytical and diagnostic sensitivities of each method. The turbidimetric method resulted in the best analytical sensitivity (100 fg DNA/reaction), diagnostic sensitivity and specificity (100%), and time-to-positivity of the test (15 min). However, this method is highly prone to subjective error in reading the results. Moreover, HNB-, calcein-, and EBT-LAMP could respectively detect 100 fg, 1 pg, and 1 pg DNA/reaction (the analytical sensitivities) in 30, 15, and 30 min, while the diagnostic sensitivity and specificity were respectively 93.3% and 100% for them all. Interestingly, EBT-LAMP showed the lowest potential for subjective error in reading the results. This report helps judiciously choose the most appropriate visual method, taking a step forward toward the field applicability of LAMP for the detection of Mtb, particularly in resource-limited settings

Modified genome comparison method: a new approach for identification of specific targets in molecular diagnostic tests using Mycobacterium tuberculosis complex as an example

Abstract Background The first step of designing any genome-based molecular diagnostic test is to find a specific target sequence. The modified genome comparison method is one of the easiest and most comprehensive ways to achieve this goal. In this study, we aimed to explain this method with the example of Mycobacterium tuberculosis complex and investigate its efficacy in a diagnostic test. Methods A specific target was identified using modified genome comparison method and an in-house PCR test was designed. To determine the analytical sensitivity and specificity, 10 standard specimens were used. Also, 230 specimens were used to determine the clinical sensitivity and specificity. Results The identity and query cover of our new diagnostic target (5KST) were ≥ 90% with M. tuberculosis complex. The 5KST-PCR sensitivity was 100% for smear-positive, culture-positive and 85.7% for smear-negative, culture-positive specimens. All of 100 smear-negative, culture-negative specimens were negative in 5KST-PCR (100% clinical specificity). Analytical sensitivity of 5KST-PCR was approximately 1 copy of genomic DNA per microliter. Conclusions Modified genome comparison method is a confident way to find specific targets for use in diagnostic tests. Accordingly, the 5KST-PCR designed in this study has high sensitivity and specificity and can be replaced for conventional TB PCR tests