In Vitro Antibacterial Efficacy of Sutures Coated With Aloe vera and Ciprofloxacin: A Comparative Evaluation.

BACKGROUND: Sutures which are used for wound approximation can act as a reservoir of microbes at the surgical site leading to increased chances of surgical site infection (SSI). Sutures used in oral cavity are continuously bathed in saliva which results in wicking. Several studies on sutures treated with nanoparticles, antibacterial agent and various drugs to advance the therapeutical value of surgical sutures are in consideration, drug-eluting sutures has been notable in research to deliver localized effect on the site of incision. Ciprofloxacin and Aloe vera are routinely used agents in coating sutures. AIM: This study is to evaluate the antibacterial efficacy and oral biofilm inhibition of Ciprofloxacin and Aloe vera coated 3-0 silk sutures in comparison to uncoated sutures against E.coli.
MATERIAL AND METHODS: Equal segments of ciprofloxacin and aloe vera coated 3-0 silk sutures are to be incubated in E.coli culture media (blood agar) at 37°C for 24 hours in aerobic atmosphere. Plain uncoated suture served as control. Assessment was done using Total Colony Forming Units and biofilm inhibition potential of sutures. Results awaited.
RESULTS: The zone of inhibition around ciprofloxacin coated suture is nearly double than that of with Aloe vera indicted that antibacterial efficacy of ciprofloxacin is more comparatively. No inhibition zone around uncoated plain 3-0 braided silk shows that it has no significant antibacterial activity.
CONCLUSION: Within limitation of our study, it can be concluded that both ciprofloxacin and Aloe vera coated sutures have antibacterial property against gram negative E. coli and can have a promising role in prevention of SSI although it would require further in vivo validation.

INTRODUCTION

According to the World Health Organization, chronic periodontitis is one of the common dental diseases affecting human population with a prevalence rate of 10%–15%.[1] Periodontal diseases are bacterial infections associated with a complex microbiota of the dental biofilm, composed mainly by anaerobic gram-negative species. These microorganisms induce a local and systemic inflammatory response that will lead to periodontal tissue destruction, which can be often treated with surgical management.[2] Success of any surgical intervention depends on proper wound closure and absence of bacteria at the healing site. Surgical site plaque accumulation is one of the challenging problems leading to unfavorable healing. Sutures that are used for wound closure can act as a reservoir of microbes at the surgical site, leading to increased chances of surgical site infection (SSI).[3]

Sutures used in oral cavity are constantly bathed in saliva containing 7.5 × 108 microorganisms per milliliter. This results in continuous wicking of microorganisms along the suture at the surgical site, which results in a prolonged inflammatory response and SSI.[4]

According to the National Nosocomial Infections Surveillance System, Staphylococcus aureus, coagulase-negative staphylococci and enterococci spp., and Escherichia coli are among the most frequently isolated pathogens at surgical sites.[5] Ciprofloxacin was shown to have activity against a broad range of bacteria and was particularly effective against the Enterobacteriaceae and various oral pathogens.[6] Ciprofloxacin had an extremely wide range of antibacterial activity, inhibiting aerobic and anaerobic cocci and bacilli at low concentrations.[7] In addition to antibiotics, natural antibacterial agents have a great potential to be used as prophylactic agents against wound infections, mainly because antibiotic resistance may be circumvented.[8]

Aloe barbadensis Mill. (Aloe vera) belongs to Liliaceae family and has potent antibacterial, antifungal, and antiviral properties.[9] The antimicrobial effects of A. vera have been attributed to the plant’s natural anthraquinones.[10] The antimicrobial agents of A. vera gel were reported to effectively kill or greatly reduce or eliminate the growth of S. aureus, Klebsiella pneumoniae, Streptococcus pyogenes, Pseudomonas aeruginosa, E. coli, Propionibacterium acne, Helicobacter pylori, and Salmonella typhi.[11] Conceivably, the complexity of the subgingival microbiota of periodontitis may favor the colonization by these “non-oral species.” A significantly higher prevalence of E. coli, Enterococcus faecalis, K. pneumoniae, P. aeruginosa, and S. aureus was observed in periodontitis patients compared to periodontally healthy subjects.[12]

There is no available study that has compared antibacterial activity of ciprofloxacin and A. vera. This study is to evaluate the antibacterial efficacy and oral biofilm inhibition of 3-0 silk sutures coated with ciprofloxacin and A. vera in comparison to uncoated sutures against E. coli.

MATERIALS AND METHODS

The study used an in vitro experimental design and was conducted in the Department of Microbiology, SRM Institute of Medical Sciences, Potheri, Tamil Nadu, India. Drug coating of sutures was carried out at the College of Pharmacy, SRM Institute of Science and Technology, Chennai, Tamil Nadu, India.

Study groups

Group I: sutures coated with ciprofloxacin

Group II: sutures coated with A. vera

Group III: uncoated sutures (negative control)

Laboratory procedures

Pretreatment of sutures

The 3-0 silk sutures were scoured to remove any traces of impurities on their surface. The silk suture was scoured in 1% NaOH solution for 1 minute at room temperature and washed with distilled water.

Preparation of sutures coated with A. vera

A. vera powder was purchased and authenticated. Under magnetic stirrer for 2 hours, 10% w/v of the powder was extracted in ethanol and concentrated under reduced pressure, and then used for coating the sutures [Figure 1]. Previously scoured sutures were dipped in the aforementioned solution and dried in desiccator similar to that of the ciprofloxacin-coated suture and evaluated for its antibacterial activity.

Figure 1

Ethanolic extract of Aloe vera

Preparation of sutures coated with ciprofloxacin

The scoured sutures were cut into small pieces and autoclaved at 121°C for 15 minutes to ensure a sterilized suture for the study. The sutures were coated using dip coating method, to ensure a uniform coating, by dipping in 5% ciprofloxacin solution and left to stand overnight. Later, the sutures were dried in a desiccator to remove the solvent adsorbed on to surface. The dried sutures were evaluated for its antibacterial activity. Similarly, another set of sutures was dipped and dried in the same way but without drug; these sutures were referred to as control sutures [Figure 2].

Figure 2

Ciprofloxacin solution in ethanol

Zone of inhibition assay

The zone of inhibition assay is a crucial parameter used to evaluate the antimicrobial efficacy of the coated sutures. For this intent, E. coli bacteria (ATCC 25922) was selected for the study and cultured on liquid nutrient medium for 24 hours to form bacterial medium [Figure 3]. The cultured bacterial suspension at a concentration of 1 × 108 colony-forming unit per milliliter was inoculated on to Muller Hinton agar medium in a Petri plate to form even bacterial overlay. Then, the sutures coated with A. vera and ciprofloxacin, and uncoated sutures were placed on the bacterial overlay and gently pressed in. Bacterial inhibition zones of all the three sutures were calculated and photographed after incubating for 24 hours at 37°C [Figure 4].

Figure 3

Escherichia coli (ATCC 25922™)

Figure 4

Inoculation of Escherichia coli

RESULTS

The zone of inhibition around ciprofloxacin-coated suture is nearly double than that around A. vera-coated suture, which indicted comparatively higher antibacterial efficacy of ciprofloxacin. The absence of any zone of inhibition around uncoated plain 3-0 braided silk shows that it has no significant antibacterial activity [Table 1 and Figure 5].

Table 1

Zone of inhibition measurements around sutures against Escherichia coli

	Group I (ciprofloxacin)	Group II (Aloe vera)	Group III (Control)
Zone of inhibition (mm)	36	10	0

Figure 5

Zone of inhibition around sutures

DISCUSSION

An in vivo study conducted by Storch et al.[13] showed that polyglactin 910 suture coated with triclosan inhibits bacterial colonization of suture after direct in vivo challenge with S. aureus in a guinea pig model. A study performed on pediatric patients by Ford et al.[14] observed that there is decreased incidence of postoperative pain and diminished edema with triclosan-coated sutures as compared to standard polyglactin 910 (noncoated) suture.

In a study conducted by Katz et al.[15], using radiolabeled bacteria, authors stated that bacterial adherence to suture materials can play a significant role in the induction of SSI. According to Brown et al.[16], intraoral suture removal can lead to bacteremia, which is a potential risk factor for developing bacterial endocarditis in high-risk patients.

Sethi et al.[17] concluded that both triclosan- and chlorhexidine-coated sutures have antibacterial property against periodontal pathogens and can have a promising role in the prevention of SSIs although it would require further in vivo validation. According to Zeiler and Grohe[18], ciprofloxacin showed rapid bactericidal action against organisms in both the logarithmic and stationary growth phases. It also had a wider spectrum of activity against gram-negative organisms. Accordingly in our study, ciprofloxacin showed a significant zone of inhibition around suture against E. coli. According to Lawrence et al.[11], A. vera leaf contains more than 75 nutrients and 200 active compounds, including 20 minerals, 18 amino acids, and 12 vitamins. These rich constituents give the A. vera gel special property of early healing and less scaring along with antimicrobial property.[11] Likewise, in our study also A. vera showed a certain amount of antibacterial activity but less when compared with that of ciprofloxacin. In our study, ciprofloxacin-coated suture showed more significant zone of inhibition against E. coli in comparison to suture coated with A. vera and plain uncoated suture. Walker et al.[19] conducted a study using chlorhexidine (4.0% v/v) as an antibacterial coating on suture against methicillin-resistant Staphylococcus aureus (MRSA), Staphylococcus epidermis, and E. coli, with Vicryl Plus as a positive control. It was found that the chlorhexidine-coated suture and Vicryl Plus had statistically equivalent zone of inhibition when tested against MRSA and S. epidermis, whereas statistically significant zone of inhibition was observed when chlorhexidine-coated suture was tested against E. coli.[19] From the results of the current study, it is evident that both the antibacterial sutures are effective against periodontal pathogens. But ciprofloxacin-coated sutures showed comparatively high antibacterial effect against E. coli.

CONCLUSION

The antibacterial-coated sutures have a promising potential in preventing the colonization of periodontal pathogens around them, thereby inhibiting biofilm formation. Within the limitation of our study, it can be concluded that both the sutures coated with ciprofloxacin and A. vera have antibacterial property against gram-negative E. coli and can have a promising role in the prevention of SSI, although it would require further in vivo validation.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.