Thermophilic <i>Pseudomonas aeruginosa</i> strain Ch39 isolated from Chignahuapan hot springs in Puebla, Mexico

Thermophilic bacteria have specific metabolic specializations to survive at high temperatures. This study focuses on Pseudomonas aeruginosa strain Ch39, a new isolate from mineral-rich thermal water from Chignahuapan, Puebla, Mexico. Biochemical testing, whole genome sequencing, and antimicrobial resistance profiling of strain Ch39 yielded significant detailed results. Genome sequencing yielded a high-quality 6.68 Mb assembly with a GC content of 66.13%, and annotation identified 4 356 protein-coding genes, including heat shock and antibiotic resistance genes. Comparative analysis of growth kinetics with the reference strains ATCC 27853 and PAO1 showed that Ch39 exhibited good growth and thermotolerance, with viability at 45°C, due to putative genetic adaptations such as heat shock proteins. Antibiotic resistance profiling showed variability in resistance profiles and the presence of resistance genes. In particular, strain Ch39 showed increased minimum inhibitory concentrations for some of the antibiotics tested, such as tetracycline (>1000 µg/mL), compared to the control strains. The observations made here emphasize the thermoadaptation of the strain and its suitability as a reservoir for antibiotic-resistance genes. This study expands our understanding of the thermophilic adaptation of P. aeruginosa and its ecological and clinical significance.