Isolation and Antibiogram of Clostridium tetani from Clinically Diagnosed Tetanus Patients

Abstract

Clostridium tetani, the etiologic agent of tetanus, produces a toxin that causes spastic paralysis in humans and other vertebrates. This study was aimed for isolation, identification, and determination of antimicrobial susceptibility of C. tetani from clinically diagnosed tetanus patients. Isolation was done from deep-punctured tissues of the foot and arm injuries of 80 clinically diagnosed tetanus patients from the Pakistan Institute of Medical Sciences hospital. We successfully screened out five C. tetani isolates out of 80 samples based on the strain-specific characteristics confirmed through biochemical testing and toxin production. A disc diffusion method was used for antimicrobial susceptibilities and C. tetani isolates showed susceptibility to cefoperazone, chloramphenicol, metronidazole, penicillin G, and tetracycline, but were found to be resistant to erythromycin and ofloxacin. During animal testing, all the infected mice developed symptoms of tetanus. The results showed that identification of C. tetani is possible using biochemical and molecular tools and that the strains of C. tetani isolated had not developed resistance against the antibiotics most often used for the treatment of tetanus.

Figure 1.

Detection of tetanospasmin gene (TetX) by PCR. Lanes A–H represent five clinical isolates of Clostridium tetani: C. tetani strains A, B, D, G, H, respectively. The size for tetanospasmin gene is 750 bp for lanes 2–6, lane M shows the molecular weight size marker (1 Kb marker, Fermentas).

Figure 2.

Mice showing the effects of injected cultured toxin (A) after 12 hours, (B) after 24 hours, with stiffness in tails and limbs, (C) at 72 hours, with death of mice.