Antiseptic sutures: clinical evaluation of microbiological efficacy

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1 DOI /s ORIGINAL PAPER Antiseptic sutures: clinical evaluation of microbiological efficacy Antonio Di Lonardo & Davide Lazzeri & Adriana Mosca & Alessandro Oliverio & Giuseppe Miragliotta & Christian Pascone & Tommaso Agostini Received: 30 December 2010 / Accepted: 30 March 2011 # Springer-Verlag 2011 Abstract The use of antiseptic sutures may constitute an interesting way to prevent early contamination of surgical wounds by microorganisms found in the environment and in the surgically sectioned cutaneous adnexa responsible for potential complications due to infection. This clinical study compares two different sutures: Polyglactin 910 plus Triclosan and Polyglactin 910. Twenty-nine patients (15 males and 14 females), aged between 22 and 53 years, were enrolled. All wounds were sutured half way using Polyglactin 910 plus Triclosan with the remaining half sutured using Polyglactin 910 of similar calibre. For each group, one or two stitches being removed on the third day, with the remaining stitches being removed on the seventh day, and then culture tests, biochemical tests and Polyglactin 910 plus Triclosan in vitro inhibition tests were conducted. Overall, 188 suture fragments were analysed. For the sutures removed after 3 days (30 for each group), the following observations were made: Polyglactin 910 plus Triclosan group, one contamination (3.3%) with Pseudomonas aeruginosa; and Polyglactin 910 group, 14 colonisations (46.6%), predominantly with Staphylococcus aureus. For the suture fragments removed on day 7 (128 in total), the following were observed: Polyglactin 910 plus Triclosan group (67 fragments), nine contaminations (13.4%) with a slight predominance of S. aureus (four cases) and P. aeruginosa (three); and Polyglactin 910 group (61 fragments), 56 contaminations (91.8%) with a marked predominance for S. aureus (43). Compared to Polyglactin 910, Polyglactin 910 plus Triclosan was less colonised by bacteria, thanks to the bacteriostatic effect of Triclosan. The reduced microbial colonisation of sutures may contribute towards better control of complications due to surgical wound infections. Keywords Surgical wound infection. Antiseptic sutures. Polyglactin 910. Polyglactin 910 plus Triclosan. Soft tissue injury Ethical standards All human studies have been approved by the appropriate ethics committee and have therefore been performed in accordance with the ethical standards laid down in the 1964 Declaration of Helsinki and its later amendments. All persons gave their informed consent prior to their inclusion in the study. Details that might disclose the identity of the subjects under study should be omitted. A. Di Lonardo : D. Lazzeri : A. Oliverio : C. Pascone : T. Agostini (*) Burns Center Unit, Hospital of Pisa, Cisanello, Pisa, Italy tommasoagostini@ymail.com A. Mosca : G. Miragliotta Microbiology Division, MIDIM Department, University of Bari, Bari, Italy Introduction Surgical wounds are frequently complicated by infections of varying degrees of precociousness and severity, giving rise to a range of clinical problems and prolonging hospitalisation with increased healthcare costs [1 10]. Such risks occur from many factors, such as the type of operation performed (clean or dirty), the general condition of the patient or the duration of surgery. The numerous aspects relating to the methods by which surgical wound infections develop are not entirely known [1 10]. It would be especially interesting to clarify the origin of the microorganisms giving rise to infection. Normally, after a clean surgical wound suture, it is

2 deemed essential to protect it against environmental contamination using near hermetic dressings. On the other hand, what would we do if we were aware that bacteria can contaminate the wound from inside rather than outside? Indeed, the skin is a major source of bacteria, mycetes and viruses, which not only reside on the epidermal surface, but extensively penetrate deep inside the cutaneous adnexa (sweat glands, sebaceous glands and hair follicles) [1 3]. When the skin is incised using a sterile scalpel, the cutaneous adnexa located along the line of incision is dissected exposing the biological (sweat and sebum) and the microbiological content of the inside of the wound. Hence, independent of the environmental bacterial flora and the efficacy of the antiseptic procedure adopted prior to incision, at the precise time when the surgical wound is created, it may become contaminated by the content of the cutaneous adnexa. The saprophytic bacterial flora, immersed in an ideal serum protein and blood culture medium, will tend to proliferate rapidly, especially if the immune defences of the host are compromised, or if antibiotic cover is inadequate. Concomitant with the irritation induced by other adnexal components (sebum and sweat), bacterial proliferation enhances the normal inflammatory response due to the tissue repair processes. Since increased inflammation also corresponds to increased exudate production, imbibition of the wound margins can also occur, with obvious negative effects (tissue maceration, hypoxia due to reduced capillary perfusion resulting from compression and impaired oxygen diffusion) this results in delayed healing, greater susceptibility to infection and poor tissue repair with potential pathological scarring. It is likely that such pathogenic mechanisms are effectively managed by the immune response in normoergic patients [1 10]. However, in hypoergic patients, such as in the cases of major trauma, major burns and exhausted cancer patients subjected to long and complex destructive surgery, reduced immune efficiency might promote the progression of such events leading to severe infections. Thus, it is essential to reassess and modify preventive strategies, also considering them potential sources of contamination, in order to more effectively combat the potential onset of such significant complications [1 5]. The application of sutures with antiseptic action, for example, may represent an interesting strategic weapon, capable of acting precisely on the bacterial flora residing in the cutaneous adnexa. Indeed, by passing through the structures of the cutaneous adnexa, the suture could immediately become contaminated and spread germs along its entire path. In theory, the presence of an antiseptic could limit this phenomenon, making the onset of localised infections less likely. Study aim The clinical study was conducted in collaboration with the Microbiology Division, establishing the following aims: 1. To verify whether the intralesional portions of the sutures used showed signs of microbial colonisation at 3 and 7 days after suturing a skin wound. Documentation of microbial colonisation of the sutures inside the wound would provide a reason for the use of antiseptic sutures. 2. To compare the type of colonisation and the bacterial load detected on the sutures with Triclosan (Polyglactin 910 plus Triclosan) compared to the sutures without Triclosan (Polyglactin 910) over time. It is important to understand any benefits resulting from the use of antiseptic sutures and the length of time these benefits last. Indeed, there would be no point using antiseptic sutures if, on its removal, there was colonisation similar to that of traditional sutures. 3. To test the sensitivity of the microorganisms isolated to Triclosan. It is useful to understand the types of germs most frequently involved and verify their sensitivity to the antiseptic under test. 4. To evaluate variations in the incidence of surgical wound infections. Materials and methods Twenty-nine patients (15 male and 14 female), aged between 22 and 53 years, were enrolled between January and March Out of these, 25 patients had undergone minor outpatient surgical operations (removal of skin tumours), while four came from the Accident and Emergency Department for the treatment of traumatic wounds within a maximum of 1 h from the trauma. Patients with pre-existing skin disorders, drug addicts, pregnant women and patients with dysmetabolic and/or systemic diseases were excluded. All patients were informed beforehand about the type of study proposed and gave their consent. After thorough cleaning, disinfection and haemostasis of the wounds, external button suturing was performed: one half of the wound was sutured using Polyglactin 910 plus Triclosan 4/0 5/0 (Polyglactin 910 plus Triclosan group), the other half with Polyglactin 910 of equal calibre (Polyglactin 910 group). No prophylaxis and/or antibiotic therapy was performed. Patients were subsequently subjected to regular outpatient check-ups (on alternating days and no more than 3 days) with dressings applied according to

3 Fig. 1 Polyglactin 910 plus Triclosan in vitro inhibition testing (USP test 4/0) need. The sutures were removed in accordance with the following plan: One or two stitches were removed early from each half of the wound on day three, with the remaining stitches removed after 7 days, on average. The intralesional portion of each suture, recognisable by the greater humidity and altered colour, was dissected under sterile conditions. Each fragment was placed in an individual sterile tube and sent immediately to the microbiology laboratory. The investigation was approved by the local ethical committee at the University Hospital in Bari, Italy. suture was immersed in one plate, and an analogous fragment of Polyglactin 910 4/0 immersed in the other. The plates were incubated at 37 C overnight and the inhibitory action assayed. Results A total of 188 suture fragments were analysed: of these, 60 (30 for each test group) were removed on day 3 (Fig. 3) and 128 (67 study group, 61 control group) removed after 7 days (Fig. 4). Surgical wound infection was not recorded in any of the cases. Microbiological testing The suture fragments were seeded on blood agar plates (Brucella agar+4% sheep s blood) within 2 h until removal. The plates were incubated overnight at 37 C. Afterwards, the bacteria grown were identified by evaluating the following: colony appearance, Gram staining and biochemical testing. The bacteria isolated from each suture fragment were then subjected to Polyglactin 910 plus Triclosan in vitro inhibition testing (Figs. 1 and 2). A bacterial suspension in isotonic saline (10 8 cells/ml) was seeded in duplicate onto plates containing Mueller Hinton medium. Part of a 5-cm-long section of a Polyglactin 910 plus Triclosan 4/0 Fig. 2 Polyglactin 910 plus Triclosan in vitro inhibition testing (S. aureus)

4 The following microbiological data were recorded for the fragments removed after 3 days: (a) (b) In the Polyglactin 910 plus Triclosan group: one contamination with Pseudomonas aeruginosa (incidence of 3.3%) In the Polyglactin 910 group: 14 positives (incidence of 46.6%) Staphylococcus aureus (nine), P. aeruginosa (three) and Candida albicans (two) On the other hand, the following were recorded for the 128 fragments removed after 7 days: (a) (b) 1 Polyglactin 910 plus Triclosan Polyglactin 910 Fig. 3 Number of contaminations after 3 days Polyglactin 910 plus Triclosan group (67 fragments): nine positives (incidence of 13.4%) S. aureus (four), P. aeruginosa (three), Acinetobacter (one) and Proteus (one) Polyglactin 910 group (61 fragments): 56 positives (incidence of 91.8%) S. aureus (43), P. aeruginosa (three), C. albicans (two), Escherichia coli (1) and Proteus (1) The bacterial load detected on the sutures was consistently lower on the Polyglactin 910 plus Triclosan fragments compared to the Polyglactin 910 fragments. Polyglactin 910 plus Triclosan inhibition test: Triclosan, the antiseptic present in Polyglactin 910 plus Triclosan sutures, is described as a very effective antimicrobial agent, especially towards Gram +ve bacteria (particularly S. aureus and Staphylococcus epidermidis), which are also the germs that are most frequently involved in wound contamination. Its bacteriostatic action is due to inhibition of bacterial lipid biosynthesis. It has poor systemic absorption and very low toxicity. The in vitro inhibition test has confirmed the marked S. aureus and S. epidermidis growth inhibitory action (growth inhibition halo of approximately 1 cm). On the other hand, it is ineffective towards Gram ve germs (P. aeruginosa and Acinetobacter). 14 Discussion This study demonstrates that sutures used for reconstructing clean skin wounds may soon become colonised by bacteria in the intralesional area, which is usually considered to be completely germ free. Presumably, these are bacteria that have migrated into the wound following the route of the suture itself or bacteria residing within the cutaneous epidermal adnexa released into the wound as a result of the surgical section or skin trauma. Microbial contamination increases progressively with passing time: indeed, on day 3 it is almost non-existent on the suture fragments with antiseptic (3.3%) and more evident on the traditional sutures (46.6%). After 7 days, microbial contamination increased slightly in the study group (13.4%) with a marked deterioration in the control group, where the presence of microorganisms was recorded on almost all samples (91.8%), thus documenting the greater efficacy of the antiseptic sutures. Furthermore, microbiological tests have shown that the antiseptic sutures, where colonised, consistently showed a low bacterial load (expressed as CFU) compared to the control sutures. From a clinical viewpoint, it should be emphasised that, in the presence of promoting factors, early colonisation of sutures can lead to complications in the form of infections. No surgical wound infections were documented in the patients enrolled, but it should be pointed out that there were no particular risk factors: intermediate age band, good state of health and minor surgical operations. In subjects weakened by severe pathologies or subjected to much more invasive surgery, the possibility that such foci might trigger localised infections is much higher and [1 10], consequently, the risk of morbidity will also be increased with consequently increased hospitalisation times and costs [1 10]. Such cases provide a strong incentive for the use of antiseptic sutures to be used for closing skin layers so as to combat Polyglactin 910 plus Triclosan Polyglactin 910 Fig. 4 Number of contaminations after 7 days 56 61

5 the potential effects of bacterial colonisation at all levels. With regard to the closure of skin layers, it should also be considered that a continuous intradermal suture is preferred to external button suturing. Indeed, the latter type of suture exposes the wound to a greater risk of contamination from the exterior, thanks to the possibility that the bacteria propagate at depth by following the numerous suture paths. Furthermore, by crossing the entire length of the wound, continuous intradermal suturing should guarantee a more uniform presence of antiseptic in the dermal layers, where the likelihood of contamination from adnexal structures is higher. References 1. Mangram AJ, Horan TC, Pearson MI, Silver LC, Jarvis WR (1999) Guideline for prevention of surgical site infection. Centres for disease control and prevention (CDC). Hospital Infection Control Practices Advisory Committee. Am J Infect Control 27 (2): Dohmen PMCE (2006) Influence of skin flora and preventive measures on surgical site infection during cardiac surgery. Surgical Infections 7(Supplement I):s13 s17 3. West H (2007) Postoperative wound infection in animals and man: comparative aspects. Am Surg 73(9): Lipsky BA, Weigelt JA, Gupta V, Killian A, Peng MM (2007) kin, soft tissue, bone, and joint infections in hospitalized patients: epidemiology and microbiological, clinical, and economic outcomes. Infect Control Hosp Epidemiol 28(II): Di Lonardo A (2007) Infective complication of the surgical site: pathogenetic hypothesis. Wound Care Times. Year V. No. 2/3. December 6. Williams M (2008) Infection control and prevention in perioperative practice. J Perioper Pract 18(7): Minchella A, Alonso S, Cazaban M, Lemoine MC, Sotto A (2008) Surveillance of surgical site infections after digestive surgery. Med Mal Infect 38(9): Olsen MA, Lefta M, Dietz JR, Brandt KE, Aft R, Matthews R, Mayfield J, Fraser VJ (2008) Risk factors for surgical site infection after major breast operation. J Am Coll Surg 207 (3): Marco F, Vallez R, Gonzalez P, Ortega L, de la Lama J, Lopez- Duran L (2007) Study of the efficacy of coated Vicryl plus antibacterial suture in an animal model of orthopaedic surgery. Surg Infect (Larchmt) 18(3): Suárez Grau JM, De Toro Crespo M, Docobo Durántez F, Rubio Chaves C, Martín Cartes JA, Docobo Pérez F (2007) Prevention of surgical infection using reabsorbable antibacterial suture (Vicryl Plus) versus reabsorbable conventional suture in hernioplasty. An experimental study in animals. Cir Esp 18 (6):