Rapid Detection of vanA Resistance Gene from E. faecalis Clinical Isolates Using Duplex Loop-Mediated Isothermal Amplification and Triplex PCR Assay

Today, the spread of vancomycin-resistant strains isolated from Enterococcus faecalis (E. faecalis) has become a major health concern worldwide. Therefore, it is essential to provide a rapid and sensitive assay for identifying vanA gene for timely and appropriate antimicrobial control of resistant enterococcal infections. For this purpose, a cross-sectional study was performed on different clinical specimens of enterococci from Imam Reza hospital, Kermanshah, Iran. The antimicrobial susceptibility testing was determined by disk diffusion and MIC methods. Triplex-PCR and duplex-LAMP assays were also used to identify vanA E. faecalis resistance gene isolates. The results of this study shown that out of 108 Enterococcus isolates, 86, 18, 2, 1, and one isolates of E. faecalis, E. faecium, E. avium, E. psudoavium, and E. raffinosus were identified, respectively. On the other hand, E. faecalis was confirmed in 87 and 88 isolates using duplex-LAMP and triplex PCR, respectively. The LAMP primer set designed in this study can reliably identify seven distinct regions of the vanA gene, and finally the sensitivity, specificity, and the positive and negative predictive values of LAMP assay were shown to be 94.19%, 72.73%, 76.19%, and 93.10%, respectively. In general, sample processing, isothermal reaction and result reporting were completed using the LAMP assay in 75 minutes. Our findings suggest that LAMP assay has been approved as an alternative to the vancomycin resistance Enterococcus genotype (vanA and vanB) compared to other methods and has the advantage of being rapid, time-consuming, and easy for diagnosis.

Evaluation of the loop-mediated isothermal amplification assay for Staphylococcus aureus detection: a systematic review and meta-analysis

Background

Staphylococcus aureus can cause many diseases and even death. It’s important to detect Staphylococcus aureus rapidly and reliably. The accuracy of a novel test named LAMP in detecting Staphylococcus aureus is unclear. Therefore, a systematic review and meta-analysis were conducted to evaluate the accuracy of the LAMP assay for Staphylococcus aureus detection.

Methods

Four databases were searched for relevant studies. Meta-DiSc 1.4.0 and Stata 12.0 were used for statistical analysis. At the same time, we used QUADAS-2 to assess the studies we included. Two groups of subgroup analysis were done to differentiate the diagnostic effects of various LAMP tests and in cases of different gold standards.

Results

11 studies were identified and 19 2 × 2 contingency tables were extracted in our study. The results showed that both pooled sensitivity and specificity of the LAMP assay were 99% (95% CI 99–100).

Conclusion

The LAMP assay demonstrated high sensitivity and specificity in diagnosing Staphylococcus aureus.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12941-022-00522-6.

Recent Developments in Phenotypic and Molecular Diagnostic Methods for Antimicrobial Resistance Detection in Staphylococcus aureus: A Narrative Review

Staphylococcus aureus is an opportunistic pathogen responsible for a wide range of infections in humans, such as skin and soft tissue infections, pneumonia, food poisoning or sepsis. Historically, S. aureus was able to rapidly adapt to anti-staphylococcal antibiotics and become resistant to several classes of antibiotics. Today, methicillin-resistant S. aureus (MRSA) is a multidrug-resistant pathogen and is one of the most common bacteria responsible for hospital-acquired infections and outbreaks, in community settings as well. The rapid and accurate diagnosis of antimicrobial resistance in S. aureus is crucial to the early initiation of directed antibiotic therapy and to improve clinical outcomes for patients. In this narrative review, I provide an overview of recent phenotypic and molecular diagnostic methods for antimicrobial resistance detection in S. aureus, with a particular focus on MRSA detection. I consider methods for resistance detection in both clinical samples and isolated S. aureus cultures, along with a brief discussion of the advantages and the challenges of implementing such methods in routine diagnostics.