Gunshot-related transport of micro-organisms from the skin of the entrance region into the bullet path

Abstract

The skin defect of a gunshot entrance wound is caused by the retrograde and anterograde displacement of skin particles. In the present study, we investigated whether gunshots to bacterially contaminated skin are associated with the transport of micro-organisms into the bullet path. The shots were fired into composite models of pig skin and gelatin blocks. The outer surface of the skin was covered with a thin layer of a defined bacterial suspension [green fluorescent protein-labelled Escherichia coli in the preliminary test and Staphylococcus epidermidis, DSM 1798, in the main test series]. After the bacterially contaminated fluid had dried, test shots were fired from a distance of 5 and 10 m using calibre .38 Special cartridges with different bullet types (round nose, truncated cone, hollow point and flat nose). Subsequent bacteriological analyses showed that all the bullet tracks in the gelatin serving as tissue simulant contained displaced micro-organisms from the skin surface. The results are presented and discussed with reference to the transport of skin particles into the depth of the wound track.

Gunshot-related displacement of skin particles and bacteria from the exit region back into the bullet path

“…Nine pieces of pig skin, each measuring 25×10 cm, were stained in a haematoxylin bath, dried and disinfected as described in a previous study [6]. Directly before the test shots, 1 ml of a bacterial suspension (S. epidermidis, DSM 1798, 10 8 CFU/ml) was applied to the skin surface (Fig.…”

“…On the other hand, the gunshot entrance wound is typically characterised by a skin defect that could be shown to be caused by anterograde and retrograde displacement of macroscopically visible and microscopically small skin particles [5]. Furthermore, it has been demonstrated that microorganisms from the skin of the entrance site are carried along the whole length of the bullet track and may therefore constitute a source of infection in gunshot victims [6].…”

“…Therefore, the present study was undertaken to investigate whether, in experimental gunshots, microorganisms can be displaced in a retrograde direction from the skin of the exit region back into the bullet path, thus creating a further source of infection in gunshot wounds. As in our previous experiments [6], we used composite models of gelatin and pig skin for test shots with different bullet types. A preliminary test was performed using gelatin blocks and pig skin contaminated with green fluorescent protein (GFPuv)-labelled bacteria to investigate whether a retrograde transport of microorganisms back into the bullet path can be demonstrated.…”

Micro-CT features of intermediate gunshot wounds covered by textiles

“…For each group (a cotton, b jeans, c leather, d nylon) and firing distance tested (5,15, and 30 cm), the macroscopic features of the fabrics and the underlying skin and the micro-CT reconstructions (frontal and lateral views) of the wounds are represented particular, it was assumed that the density of textile fibers in the bullet entrance was higher than that in the exit site. This general rule, however, has been recently questioned by Vennemann et al [26] in an experimental study performed on a porcine skin-gelatine model [27,28]. The authors observed a retrograde displacement of fibers from the clothing back into the bullet path.…”

Experimental simulation of reentry shots using a skin-gelatine composite model

“…The principal technical procedure has already been described in previous papers [4,7,20,21]. In order to imitate a reentry shot constellation, two cylindrical gelatine blocks (24×8 cm in size) were tightly wrapped in pieces of skin from the belly region of slaughtered pigs and arranged one behind the other by means of a metal rack which permitted the distance between the cylindrical segments to be varied (Fig.…”