Exploring patterns of serum CRP level reduction in response to treatment initiation in Latvian patients with pulmonary tuberculosis: the impact of Mycobacterium tuberculosis genotype

In tuberculosis (TB), serum CRP levels vary with patient- and disease-related factors, and fail-ure to achieve a two-fold reduction within the first two weeks may indicate adverse treatment outcomes. Given reported Mycobacterium tuberculosis (Mtb) genotype-related variability in immune response and clinical presentation, this study evaluated whether Mtb genotype influ-ences early changes in serum CRP levels. Clinically relevant data, including serum CRP levels at baseline (CRPb) and 10–12 days after treatment initiation (CRP10–12d), were retrieved from patients’ medical records (n=35). Whole-genome sequencing was performed on all patients’ Mtb isolates, and TB-Profiler was used to assign genotypes and detect drug resistance-associated genomic variants, interpreted alongside phenotypic drug susceptibility (DS) data. Overall, considerable Mtb genotype diversity was observed: LAM (28.6%), T (25.7%), Bei-jing (17.1%), Haarlem and Ural (11.4% each), and others (5.8%). Patients infected with Mtb of LAM/Ural genotypes more frequently had lung cavitations, lower body mass index, and higher CRPb levels than those infected with T/Haarlem or Beijing genotypes, although differ-ences were not statistically significant. DS cases (n=27) were further analysed for treatment-specific effects. In 10–12 days, serum CRP levels significantly declined in the LAM/Ural and T/Haarlem groups (p=0.011 and p=0.025, respectively) but not in the Beijing group (p=1.000). CRP10–12d levels followed a similar pattern to CRPb, with higher values found in patients in-fected with LAM/Ural genotypes. In conclusion, the observed trends align with previous re-ports and suggest that the Mtb genotype may influence early CRP dynamics. The clinical sig-nificance of these findings is yet to be established.