Stenotrophomonas maltophilia as a part of normal oral bacterial flora in captive snakes and its susceptibility to antibiotics

Only little is known about normal oral bacterial flora in captive snakes containing Stenotrophomonas maltophilia. This microbe has been reported as a causative agent of numerous infections in reptiles. Therefore, the goal of the study was to detect its presence in the mouths of a significant number of healthy captive snakes and determining its susceptibility to antibiotics at 30 and 37 °C. The isolates were obtained in 1999–2005 from mouth swabs of 115 snakes of 12 genera and 22 species—most often Elaphe guttata (24 individuals; 20.9%). Susceptibility to 24 antibiotics was tested by the microdilution method. The microbe was demonstrated in 34 (29.6%) individuals. Overall, 47 strains of S. maltophilia were acquired. Evaluation using PFGE profiles and antibiograms resulted in confirmation of one strain of S. maltophilia in 23 (20.0%) individuals, two strains in nine (7.8%) and three in two (1.8%) snakes. All tested antibiotics were more effective at 37 °C, with the partial exception of cotrimoxazole and cefoperazone/sulbactam. At a temperature of 37 °C, the lowest frequency of resistance to levofloxacin (no resistant strains), cotrimoxazole and ofloxacin (97.9% of susceptible strains) was recorded. At 30 °C, the most active agents were cotrimoxazole (97.9% of susceptible strains), levofloxacin (91.5%) and ofloxacin (85.1%). In conclusion, S. maltophilia is present in the mouths of about one third of healthy captive snakes, showing good susceptibility to cotrimoxazole, some fluoroquinolones and aminoglycosides. The antibiotics (particularly aminoglycosides) are more effective at 37 °C.