The mechanism of ROS regulation of antibiotic resistance and antimicrobial lethality.

Misuse and overuse of antibiotics have led to serious resistance problems that pose a grave threat to human health. How to solve the increasing antibiotic resistance problem is a huge challenge. Besides the traditional strategy of developing novel antimicrobial agents, exploring ways to enhance the lethal activity of antibiotics currently available is another feasible approach to fight against resistance. Recent studies showed that ROS plays an important role in regulating both antibiotic resistance and antimicrobial lethality. ROS produced by sublethal levels of antibiotic induces antibiotic resistance through activating drug efflux pumps via MarR(Multiple antibiotic resistance repressor)-MarA(Multiple antibiotic resistance activator), triggers the protective function against stress via SoxR (Superoxide response transcriptional regulator)-SoxS (Superoxide response transcription factor), and promotes mutagenesis by induction of SOS system. On the contrary, ROS triggered by lethal levels of antibiotic promotes bacterial killing and suppresses resistance. In addition to the concentration of antibiotic, the role of ROS in mediating antimicrobial resistance and bacterial killing is also regulated by a series of genetic regulators (e.g. MazEF, Cpx, SoxR, MarRAB). Thus, how ROS contribute to antimicrobial resistance and bacterial killing is complex. In this review, we summarized the mechanism of ROS in regulating antibiotic resistance and antimicrobial lethality, which may provide references and guidance for finding new ways to enhance antimicrobial lethality of currently available antimicrobials and battling antibiotic resistance.

Evaluation of the diagnostic performance of an immunochromatographic test for Chlamydia trachomatis.

Objectives: To evaluate the diagnostic performance of different brands of immunochromatographic test (ICT) reagents for Chlamydia trachomatis using homogenized samples to provide a reference for reagent quality control. Methods: Eight commercially available ICT reagents were evaluated, of which three used the latex method and five used the colloidal gold method. Analytical performance evaluation using a pure culture broth of C. trachomatis, as well as clinical application validation using cervical epithelial cell samples acquired from the research subjects, were conducted. The concentration of C. trachomatis was quantified using a nucleic acid amplification test. Results: The limit of detection (LOD) of different ICT reagents in the analytical performance evaluation varied from 9.5 × 103 to 1 × 105 IFU/mL, and only one reagent met the LOD specified in the manufacturer's instructions. Likewise, only one reagent in the clinical application validation achieved the analytical LOD, four reagents were 2.1-4.2-fold of the analytical LODs, and three reagents failed to detect positive results in clinical samples. Conclusions: The diagnostic performance of different methods and different brands of ICT reagents in clinical practice was different from the manufacturer's instructions and the results of laboratory evaluation. The diagnostic performance of reagents should be evaluated before they are actually used in clinical practice.

Association between treatment failure in patients with early syphilis and penicillin resistance-related gene mutations of Treponema pallidum: Protocol for a multicentre nested case-control study.

Background: The widespread occurrence of syphilis remains a global public health problem. Although penicillin has been recommended as the first-line therapy for syphilis for more than 70 years, treatment failure occurs in 10-20% of patients with early syphilis. Recent studies have reported varied single-nucleotide polymorphisms (SNPs) of Treponema pallidum related to penicillin resistance. The clinical relevance of these SNPs to treatment failure in patients with early syphilis is unresolved. In this work, a protocol is developed to evaluate the association between treatment failure in patients with early syphilis and penicillin resistance-related gene mutations of T. pallidum. Methods: A multicentre nested case-control study is designed, and patients who are diagnosed with early syphilis and treated with penicillin will be recruited for the study cohort. Before the first treatment, baseline information and biological specimens will be collected from the subjects, and serological tests for syphilis will be performed. Each participant will be followed up at 1, 3, 6, 9, and 12 months after the first treatment, and the clinical manifestations and serum non-treponemal test titres will be evaluated at each follow-up. Patients who will fail treatment are defined as cases, and those who will respond to treatment are defined as controls. Tests for SNPs related to penicillin-binding proteins and Tp47 will be performed in these cases and controls. Survival analysis is used performed to identify gene mutations of T. pallidum related to penicillin resistance and their combinations associated with treatment failure. Discussion: This protocol provides a practical clinical study design that illustrates the role of gene mutations of T. pallidum related to penicillin resistance in the treatment outcome of patients with early syphilis.