Sensitive and Specific Loop-Mediated Isothermal Amplification Assays for Detection of Salmonella, CTX-M-1 Group Genes, mph(A), and ermB in Stool and Blood Samples Based on Orange to Green Visible Dye.

Salmonella is a globally prevalent foodborne bacterium, and ceftriaxone and azithromycin have been regarded as drugs of choice for treating Salmonella infections, particularly in children. With the growing incidence of ceftriaxone and azithromycin resistance in Salmonella, there is an urgent requirement for a rapid and dependable gene testing approach to enhance the efficacy of treating Salmonella infections. Utilizing the orange to green visible dye approach, this study developed loop-mediated isothermal amplification (LAMP) assays for the sensitive and specific detection of Salmonella, ceftriaxone and azithromycin resistance genes (including CTX-M-1 group, mph(A), and ermB genes) in stool and blood samples. The specificity and sensitivity of primers during the LAMP assays for detection of Salmonella, CTX-M-1 group, mph(A), and ermB genes were determined in this study. The detection threshold for Salmonella was found to be 1.5 × 103 colony-forming units (CFU)/mL, while it was 1.5 × 102 CFU/mL for CTX-M-1 group genes (including blaCTX-M-3, blaCTX-M-15, and blaCTX-M-55), 1.5 × 102 CFU/mL for mph(A), and 1.5 × 102 CFU/mL for ermB, showing 10-103-fold, 103-fold, and 105-fold increased sensitivity compared with the polymerase chain reaction assay, respectively. Results indicated that the LAMP primers designed for Salmonella, CTX-M-1 group, mph(A), and ermB genes possess high specificity (100%) and sensitivity (over 94%). This novel approach advocates its application in detecting Salmonella, CTX-M-1 group, mph(A), and ermB genes.

Acoustic, aerodynamic, and vibrational effects of ventricular folds adduction in an ex vivo experiment.

Objectives: The excessive adduction of ventricular folds has been observed in patients with dysphonia and professional singers. Whether these changes in the ventricular folds are the cause or just a result of disease progression remains unclear, and their potential pathological and physiological implications are yet to be determined. This study aimed to examine the impact of different degrees of ventricular adduction on acoustics, aerodynamics, and vocal fold vibration. Methods: The excised models of mild and severe ventricular adduction were established. We recorded the vibration pattern of vocal folds and ventricular folds and measured acoustic metrics, including fundamental frequency (F0), Jitter, Shimmer, harmonic-to-noise ratio (HNR), and sound pressure level (SPL). Furthermore, we evaluated the aerodynamics index through phonation threshold pressure (PTP), phonation instability pressure (PIP), mean flow rate (MFR), phonation threshold flow (PTF), and phonation instability flow (PIF). Results: Irregular vibrations of the ventricular fold were observed during ventricular adduction. Notably, mild and severe ventricular adduction conditions showed a significant increase in PTP, Shimmer, and Jitter, whereas MFR, PIF, and HNR decreased compared with the control condition. Conclusions: Ventricular adduction leads to the deterioration of acoustic and aerodynamic parameters. The aperiodic and irregular vibration of the ventricular folds may be responsible for this phenomenon, although further experiments are warranted. Understanding the functioning of ventricular folds can be beneficial in directing the treatment of muscle tension dysphonia and improving voice training techniques.Level of evidence: level 4.

Change of Phonation in Canines Without Vocal Fold Paralysis After Vocal Processes Resection.

The effects of the vocal processes resection on phonation in an animal without vocal fold paralysis have not been clarified. The present study used an in vivo animal model with vocal processes resection and excised larynges phonation model to investigate the effects of the vocal processes resection on phonation. Six months after resection of bilateral vocal fold processes, glottal airflow, subglottal air pressure, acoustic signals, and ultra-high-speed video images were recorded in the excised larynges phonation model of canine. Glottal aerodynamic parameters were estimated by calculation of subglottal pressure and glottal flow. Histological analyses of the scarred were assessed for wound healing completion. In the vocal processes resection group, fundamental frequency(F0) and vocal intensity decreased, and the Jitter and Shimmer increased significantly. The phonation threshold power(PTW) of the vocal processes resection was significantly higher than controls. The vibratory amplitude of the vocal fold posterior and visual vocal fold vibration length increased. Expression of collagen I-III in scarred tissue samples in vocal process resection was similar to controlling soft tissue specimens around vocal process cartilage, and collagen fiber formed matured thick bundles. The results suggest that the F0, voice quality, and vocal intensity significantly decreased after complete wound healing of vocal processes resection in canines without vocal folds paralysis. The higher PTW and posterior scarred vocal vibration may be the dynamic reasons.