## 5 Bridging Concept and Practice in the Implementation of National Surveillance Studies  
Despite the current consensus in the literature that _C. trachomatis_ remains largely susceptible to first-line antimicrobials, the global landscape of AMR would benefit from a proactive surveillance in this case as well to prevent the emergence of undetected resistance patterns. The lack of standardized and routine antimicrobial sensitivity testing for _C. trachomatis_ contributes to a gap in knowledge regarding potential shifts in its resistance profile [58], most notably in high-prevalence regions with extensive antibiotic usage. Given the documented cases of reduced susceptibility and occasional treatment failures [8; 9; 10; 11], it can be argued that there is a need for much more national surveillance studies that systematically assess _C. trachomatis_ sensitivity to commonly prescribed antimicrobial agents. A proposed surveillance algorithm to conduct such monitoring is presented in Table 2 and a simplified diagram in Figure 1. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Step** & **Process** & **Description** \\ \hline \multirow{2}{*}{1} & Clinical case identification or & Recognizing suspected _C. trachomatis_ infections in primary, secondary, and tertiary \\  & screening programs & care as well as in STI clinics in symptomatic individuals; conducting targeted \\  & & screening programs to detect _C. trachomatis_ infections in asymptomatic individuals \\ \hline \multirow{2}{*}{2} & Sample collection and transport & Collecting urogenital, anorectal, and pharyngeal specimen for testing while \\  & & ensuring proper storage and transport to clinical microbiology laboratories \\ \hline \multirow{2}{*}{3} & Laboratory confirmation of infection & Performing nucleic acid amplification tests for diagnosis; if positive, alerting \\  & & clinicians in step 1 for more samples (if necessary) to conduct AST \\ \hline \multirow{2}{*}{4} & \multirow{2}{*}{Conducting AST of isolates} & Conducting culture-based AST and/or molecular assays to detect resistance \\  & & markers (contingent upon availability in the reference laboratory) \\ \hline \multirow{2}{*}{5} & \multirow{2}{*}{Data integration and analysis} & Aggregating results to identify shifts in MICs and other resistance patterns/trends \\  & & across different settings; developing regional and national antibiograms \\ \hline \multirow{2}{*}{6} & \multirow{2}{*}{Genomic investigation} & Employing whole-genome sequencing and next-generation sequencing to monitor \\  & & resistance-associated mutations and strain evolution (contingent upon availability) \\ \hline \multirow{2}{*}{7} & \multirow{2}{*}{Surveillance reporting} & Sharing findings with healthcare providers on all levels, public health agencies, \\  & & and relevant stakeholders to inform further decisions \\ \hline \multirow{2}{*}{8} & \multirow{2}{*}{Guideline updates and policy} & Adjusting treatment protocols (if necessary) and national healthcare policies based \\  & & on the analysis of surveillance data to guide clinical action and \\  & & policy development \\ \hline \end{tabular} Abbreviations: AST— antimicrobial susceptibility testing; MC—minimal inhibitory concentration; STI—sexually transmitted infections.  
\end{table} 
Table 2: Proposed surveillance algorithm to monitor _Chlamydia trachomatis_ (_C. trachomatis_) antimicrobial susceptibility trends. A viable strategy should integrate both phenotypic and genotypic approaches to obtain a full picture of antimicrobial susceptibility trends. Traditional cell culture-based AST methods remain valuable for assessing MICs and MCCs, yet their labor-intensive nature and lack of standardized breakpoints hinder their routine application [56; 57; 70]. On the other hand, molecular methods--with examples such as PCR-based resistance marker detection and next-generation sequencing (NGS)--offer rapid, high-throughput insights into genetic determinants of resistance [31; 64; 65].