Battling Resistance: Understanding Antibiotic Resistance in Pseudomonas sp. from Kinniya and Wahawa Hot Springs

Certain Pseudomonas species can cause human diseases. This study focused on identifying antibiotic-resistant genes (ARG) in Pseudomonas species isolated from geothermal hot springs in Sri Lanka, specifically Kinniya (KY)(n=15) and Wahawa (WH)(n=2). Antibiotic sensitivity tests (ABST) were conducted using the Kirby-Bauer disk diffusion method for kanamycin, gentamycin, streptomycin, and ciprofloxacin. Real-time PCR with gene-specific primers was employed to detect aminoglycoside and quinolone-resistant genes (aph (3’)-VI, aac (6’)-I, aac (3)-II, gyrA, ParC). Out of the 17 examined isolates (Pseudomonas sp., n=11; Pseudomonas aeruginosa, n=6), Pseudomonas sp. from KY displayed resistance to all antibiotics, while WH showed resistance only to gentamycin and streptomycin. Resistance to two or more antibiotics was higher in the genus Pseudomonas sp. (75.54%) than in Pseudomonas aeruginosa (25.33%). The most frequently identified ARG was gyrA (66.66%), particularly in KY isolates. Notably, aac(3)-II and gyrA were detected in both WH isolates. The gyrA is the commonly found quinolone-resistance gene, and aac(3)-II is the aminoglycoside resistance gene. The gyrA and aac (3)-II were the most common co-existing resistance gene pattern (23.52%). Pseudomonas sp. exhibited co-existing resistance genes in 58.88% of cases, while 29.41% of P. aeruginosa isolates harbored them. Antibiotic-resistant Pseudomonas spp. were found in both hot springs, but fewer isolates from Wahawa (n=2) limit clear comparison with Kinniya. KY is more urbanized or populated by tourists than WH; there may be higher exposure to antibiotics from human activities. This study highlights the complexity of antibiotic resistance in Pseudomonas species from geothermal hot springs, emphasizing the importance of comprehensive genetic analysis for understanding their resistance patterns.