Effects of seven antibiotics on the growth and development of Phaenicia sericata (Diptera: Calliphoridae) larvae.

Maggot therapy is used for patients with severe tissue destruction, who often receive antibiotics concurrently. Therefore, we studied the effects on maggots of ampicillin, cefazolin, ceftizoxime, clindamycin, gentamicin, mezlocillin, and vancomycin in concentrations of 1, 10, 100, and 1,000 times the average minimum bactericidal or bacteriostatic concentration against highly susceptible organisms. There was a reduction in larval survival in media with gentamicin at concentrations of 1,000 times the average pharmacologic level, or 4,000 micrograms/ml (2.7% survival), versus lower concentrations (80-88% survival). Maturation of the surviving pupae to adults also was decreased at this concentration. Media with cefazolin concentrations of 100 times the average bacteristatic level, or 800 micrograms/ml, also led to a significant decrease in larval survival (70% versus 80-88%). There were no differences in larval survival, rate of maturation, or pupal weights for organisms reared on media containing ampicillin, ceftizoxime, clindamycin, mezlocillin, or vancomycin. P. sericata matured normally--and thus can be used therapeutically--when exposed to standard pharmacologic levels of the 7 antibiotics tested. Furthermore, the methods employed herein may be helpful to forensic entomologists attempting to develop models for drug ingestion by maggots.