Adherence of methicillin-resistant Staphylococcus pseudintermedius to suture materials commonly used in small animal surgery

Characterizing biofilm formation of Staphylococcus pseudintermedius in different suture materials

Staphylococcus pseudintermedius is the primary cause of pyoderma and surgical site infection (SSI) in dogs, and biofilm formation is the main reason for persistent SSI. The presence of biofilm in medical devices can directly impact treatment. Methicillin-resistant S. pseudintermedius (MRSP) emerged rapidly in companion animals, limiting treatment options. MRSP is a public health problem since zoonotic transmission can occur. The study seeks to evaluate biofilm formation capacity via Staphylococcus pseudintermedius collected from dogs affected by topical infections, in suture materials commonly used in companion animal surgery. We tested segments of four types of sutures. Biofilm production was measured by staining with safranin and colorimetric absorbance measurement. We calculated colony-forming units (CFUs) for each type of sutures and visualized biofilm via Scanning Electron Microscopy (SEM) images. The genes associated with biofilm formation (icaA and icaD) were identified using PCR. The colorimetric tests showed that the biofilm is most abundantly formed on the cotton sutures and polyglactin 910. The ability to form biofilm on polypropylene and nylon sutures has also been demonstrated, although at varying intensities. PCR revealed the presence of the two genes (icaA and icaD) in all the isolates. We used a positive control using a reference strain and negative control without bacteria for comparisons. Suture material allowing biofilm formation makes it difficult to prevent and treat surgical site infections. Therefore, it is important to know which suture thread is more susceptible to biofilm formation by bacteria to prevent possible secondary infections at surgical sites.

Two Novel Bacteriophages Control Multidrug- and Methicillin-Resistant Staphylococcus pseudintermedius Biofilm

As a primary bacterial pathogen in companion animals, Staphylococcus pseudintermedius has zoonotic potential. This pathogen exhibits multidrug resistance, including resistance to methicillin, and biofilm-forming ability, making it hard to eradicate with antimicrobial agents. One potential alternative is bacteriophage therapy. In this study, we first characterized the antimicrobial resistance profile of S. pseudintermedius from canine samples and isolated two novel bacteriophages, pSp-J and pSp-S, from canine pet parks in South Korea to potentially control S. pseudintermedius. The biological characteristics of phages were assessed, and the phages could infect most of the methicillin-resistant S. pseudintermedius strains. We found that these phages were stable under the typical environment of the body (~37°C, pH 7). We also assessed bacterial lysis kinetics using the two phages and their cocktail, and found that the phages could prevent biofilm formation at low doses and could degrade biofilm at high doses. Taken together, this study demonstrates that bacteriophages pSp-J and pSp-S isolated in this study can be used to potentially treat methicillin-resistant S. pseudintermedius.

Randomized, controlled clinical trial to assess the effect of antimicrobial-impregnated suture on the incidence of surgical site infections in dogs and cats

OBJECTIVE

To evaluate the prophylactic efficacy of triclosan-coated (TC) suture in preventing surgical site infections (SSIs) in dogs and cats undergoing surgical procedures.

ANIMALS

862 animals (794 dogs and 68 cats).

PROCEDURES

Incidences of SSI of surgical wounds closed with TC suture and surgical wounds closed with non-TC suture occurring between the time of surgery and 1 month postoperatively were compared. Animals were randomly assigned to TC or non-TC suture groups. When TC suture was assigned, all suture available as TC material was used rather than non-TC suture. Presence of an SSI was determined by an owner questionnaire or direct examination.

RESULTS

Overall, 50 of 862 (5.8%) animals developed SSIs. Incidence of SSI was 6% (24/428) in the non-TC suture group and 6% (26/434) in the TC suture group. No significant difference was found in the incidence of SSI between groups. No significant difference was detected in the incidence of incisional problems (eg, redness, dehiscence, and seroma formation) between animals in which TC suture was used and those in which non-TC suture was used. On multivariable analysis, other factors were associated with increased SSI rates, including an incision length > 10 cm, surgery performed by the soft tissue surgery department, and anesthesia duration of > 240 minutes.

CONCLUSIONS AND CLINICAL RELEVANCE

No significant difference in incidence of SSI was detected between animals undergoing surgical procedures performed with non-TC versus TC suture.

Investigation of the in vitro antimicrobial activity of triclosan-coated suture material on bacteria commonly isolated from wounds in dogs

OBJECTIVE

To investigate in vitro effects of triclosan coating of suture materials on the growth of clinically relevant bacteria isolated from wounds in dogs.

SAMPLE

6 types of suture material and 10 isolates each of methicillin-susceptible Staphylococcus pseudintermedius, methicillin-resistant S pseudintermedius, Escherichia coli, and AmpC β-lactamase and extended-spectrum β-lactamase-producing E coli from clinical wound infections.

PROCEDURES

Isolates were cultured on Mueller-Hinton agar with 3 types of triclosan-coated suture, uncoated counterparts of the same suture types, and positive and negative controls. Zones of inhibition (ZOIs) were measured after overnight incubation. Sustained antimicrobial activity assays were performed with susceptible isolates. The ZOI measurements and durations of sustained antimicrobial activity were compared among suture types and isolates by statistical methods. Suture surface characteristics and bacterial adherence were evaluated qualitatively with scanning electron microscopy.

RESULTS

ZOIs were generated only by triclosan-coated materials; triclosan-coated suture had sustained antimicrobial activity (inhibition) for 3 to 29 days against all tested pathogens. The ZOIs around triclosan-coated suture were significantly greater for S pseudintermedius isolates than for E coli isolates. Bacterial adherence to uncoated polyglactin-910 was greatest, followed by triclosan-coated polyglactin-910, and then uncoated monofilament sutures, with least adherence to coated monofilament sutures.

CONCLUSIONS AND CLINICAL RELEVANCE

Surface characteristics of suture materials may be as important or more important than triclosan coating for microbial inhibition; however, triclosan coating appeared to affect bacterial adherence for multifilament sutures. Triclosan-coated, particularly monofilament, sutures inhibited pathogens commonly isolated from wounds of dogs, including multidrug-resistant bacteria. Further studies are required to assess clinical efficacy of triclosan-coated suture materials in vivo.

Ex vivo comparison of intradermal closures with conventional monofilament suture vs unidirectional barbed suture in dogs

OBJECTIVE

To evaluate the mechanical properties, strength, and quality of seal provided by continuous intradermal suture lines closed with barbed suture vs monofilament suture.

STUDY DESIGN

Experimental study.

SAMPLE POPULATION

Forty-eight full-thickness wounds in canine cadavers.

METHODS

Four-centimeter-long parasagittal cutaneous wounds were created in canine cadavers. Each intradermal closure was closed with smooth monofilament suture and terminated with a 2 + 1 Aberdeen knot (n = 24) or a unidirectional barbed suture terminated with a single end pass (n = 24). Wounds (n = 12/group) were harvested, and a servohydraulic machine applied tensile load perpendicular to the long axis of the suture line. A load-displacement curve was generated; maximum load, displacement, stiffness, and mode of construct failure were recorded. Harvested wounds were placed in a watertight construct to measure the volume of fluid leaking over 3 minutes at 1.0 ± 0.1 psi.

RESULTS

Stiffness did not differ between constructs (P > .05). Incisions closed with monofilament sutures sustained higher maximum load (311.21 N ± 87.40) and displacement at failure (21.19 mm ± 4.51) compared with those with barbed sutures (116.38 N ± 42.82 and 15.03 mm ± 2.32, respectively, P < .05). Closures with monofilament sutures leaked more (4.38 mL ± 7.90) compared with those with barbed sutures (0.15 mL ± 0.43, P < .05).

CONCLUSION

Monofilament sutures resulted in stronger constructs, whereas barbed suture constructs provided a better watertight seal.

CLINICAL SIGNIFICANCE

While unidirectional barbed sutures may improve watertight skin closure, surgeons should consider using conventional monofilament sutures when mechanical strength of the closure is of primary concern.

Comparison of Knotless Barbed Suture Versus Monofilament Suture in the Oral Cavity of Cats

The present study compares a knotless, barbed, absorbable suture material against a conventional monofilament absorbable suture material in oral mucosal wound closure. The parameters measured include time of closure and differences in healing at 2 and 4 weeks postoperatively. A prospective study comparing a knotless, barbed suture system with conventional absorbable sutures was undertaken in 19 cats. Nineteen cats had full mouth extractions performed. Following the extraction procedures, the incisions in the arcades (maxillary and mandibular) were apposed with the barbed, knotless suture system in a continuous pattern on one side and with a conventional smooth suture in an interrupted pattern on the other. Suturing times for each arcade were recorded. The material used to close the first side of each cat varied. Healing, dehiscence, and other complications were assessed at 2 and 4 weeks postoperatively. The average closure time (± standard deviation) per quadrant with conventional monofilament suture was 8.7 (±1.3) minutes, while barbed suture required an average of 5.1 (±1.1) minutes per quadrant to complete the suture. This difference (95% confidence interval) of 3.6 (±3.2-4.1) minutes per quadrant was statistically significant ( P < .001). Dehiscence and ranula-like swelling formation were noted as uncommon postoperative complications, but the differences were not significant between the groups. Barbed, knotless sutures resulted in faster closure times than conventional, simple interrupted, monofilament sutures with similar healing and complication rates. To the author’s knowledge, there is no current literature comparing conventional absorbable monofilament sutures to a knotless, barbed, absorbable suture system for closure of oral mucosal incisions in cats.

Polymer sutures for simultaneous wound healing and drug delivery - A review

Drug delivery using suitable polymeric devices has gathered momentum in the recent years due to their remarkable properties. The versatility of polymeric materials makes them reliable candidates for site targeted drug release. Among them biodegradable sutures has received considerable attention because they offer great promises in the realm of drug delivery. Sutures have been found to be an effective strategy for the delivery of antibacterial agents or anti-inflammatory drugs to the surgical site. Recent developments yielded sutures with improved mechanical properties, but designing sutures with all the desirable properties is still under investigation. This review is an attempt to analyze the recent developments pertaining to biologically active sutures emphasizing their potential as drug delivery vehicle.