Small Animal Review

The sensitivity profiles of many organisms isolated from reptiles are not well understood, thereby making empirical antibacterial use ahead of culture and sensitivity testing problematic. An article by Tang et al (2020) (Journal of the American Veterinary Medical Association doi.org/10.2460/javma.257.3.305) reports on the commonest bacteria isolated from reptilian samples and their antimicrobial susceptibility patterns. Cultures from 61 samples submitted from a variety of reptile groups and several different sites yielded 129 isolates.

Gram-negative bacteria comprised 96/129 isolates with a wide variety of genera evident. Gram-negative bacteria were generally susceptible to aminoglycosides (not neomycin), second-generation fluoroquinolones (not orbifloxacin) and third-generation cephalosporins. They were usually resistant to penicillin, first- and second-generation cephalosporins, clindamycin and azithromycin (16/22). Enterococcus species were often susceptible to chloramphenicol, gentamicin, and penicillin and were resistant to amikacin, fluoroquinolones, ceftazidime, clindamycin, and trimethoprim-potentiated sulphonamide (TMS). All Staphylococcus species were widely susceptible.

The authors recommend the use of amikacin or tobramycin rather than gentamicin for Gram-negative infections because of lower toxicity, but say TMS is a useful empirical antimicrobial as it is less toxic and many Gram-negative bacterias are sensitive to it (not Pseudomonas). For the empirical treatment of Gram-positive bacteria the authors recommend doxycycline and a penicillin, pending culture and sensitivity results.