An unpredicted side effect of prophylactic antibiotic use

We investigated the effects of cefazolin sodium (CS), on wound healing in rats.

Forty rats in which an incisional wound model was created by removing two skin strips (4×1 cm), and suturing the wound edges, were included. Four groups were formed in a randomized way with each having 10 rats. The Control group (Group 1) received 1 cc 0·9% NaCl twice daily, whereas Group 2 received single-dose preoperative 30 mg/kg CS, Group 3 received single-dose preoperative 30 mg/kg CS followed by the same dose for three postoperative days, and Group 4 received single-dose preoperative 30 mg/kg CS followed by the same dose for seven postoperative days (via i.p. route). On the first day of the study, as the wound was created, a skin strip of 1×1 cm area was collected for bacteriologic examination. On the third day, specimens were acquired from the incision for histopathologic examination. The rats were sacrificed on the seventh day and more specimens were gained for histopathologic, tensiometric, and bacteriologic tests.

Group 4 demonstrated disrupted normal skin flora; reduced inflammatory cell density, fibroblastic activity, and collagen density; and decreased wound tensile strength. The histopathologic findings with Groups 2 and 3 were as same as with Group 4 and wound tensile strength showed no significant difference compared with the Control group. Group 2 revealed no significant difference compared with the Control group with regard to all parameters.

Seven-day CS therapy had a negative effect on wound healing and changed the normal skin flora.