The Activities of Antimicrobials Against Isolates and Evaluation of Clinical Outcomes Among Treatment Regimens in Patients with Infections: A Retrospective Multicenter Cohort Study.

Purpose: , a multidrug-resistant pathogen can cause hospital-acquired infections such as pneumonia, or bloodstream infection. infection is associated with high mortality rates. This retrospective study examined the antimicrobial susceptibility profile of clinical isolates and evaluated clinical outcomes, treatment regimens, and risk factors associated with 30-day mortality or treatment failure of infections at three tertiary care hospitals in Central Thailand.

Patients And Methods: The characteristics, microbiological data, and clinical treatment outcomes were derived from medical records obtained from three tertiary care hospitals in Central Thailand from January 2017 to October 2022. The primary outcomes were treatment failure and 30-day mortality. The antimicrobial susceptibility rates of trimethoprim-sulfamethoxazole (TMP-SMX), levofloxacin, and ceftazidime were determined by minimum inhibitory concentration (MIC), which were based on broth microdilution and clear zone diameters using the disk diffusion method. However, we also report the susceptibility of minocycline and tigecycline in some clinical strains (n = 149) and determined by MIC with E-test method.

Results: The antimicrobial susceptibility rates to TMP-SMX, levofloxacin, and ceftazidime were 97.1%, 93%, and 55.3%, respectively. The treatment failure rate and 30-day mortality were 66.3% and 49%, respectively. Significant factors associated with treatment failure included APACHE II score ≥15 (OR 3.37, 95% confidence interval (CI) 1.46-7.76), polymicrobial infections (OR 3.20, 95% CI 1.35-7.55). The significant factors associated with reduced treatment failure was treatment with TMP-SMX-based regimen (OR 0.29, 95% CI 0.11-0.76). The 30-day mortality rate was associated with APACHE II score ≥15 (OR 3.27, 95% CI 1.45-7.39) and septic shock (OR 2.53, 95% CI 1.36-4.69).

Conclusion: The results indicate a high mortality rate for infection. The predictive factors for an unfavourable outcome were severity of illness, septic shock, and non-use of TMP-SMX. Therefore, a TMP-SMX-based regimen is recommended for the treatment of infections.