Introduction
Most common Health Care Associated Infections (HAI) are Urinary tract infection (UTI) – 33%, Pneumonia – 15%, Surgical Site Infections (SSI) – 15%, Blood stream infections – 13%, & other miscellaneous infections – 24%. 1 SSI is defined as infection at the surgical site that occurs within 30 days of the surgical procedure or within one year – if there is an implant or foreign body such as prosthetic heart valve or joint prosthesis. 2 Wound infections are always multifactorial.3 Risk factors for SSI include co-morbidity, malnutrition, nicotine, 4 suture and implanted foreign material.6, 5 SSI increases morbidity & mortality in post surgical patients 3, & also increases hospital stay, it affects quality of life and increases financial burden to healthcare system. 10, 9, 8, 7 it may lead to major complications such as sepsis and death. 11 Patient related risk factors are smoking, obesity and diabetes. 14, 13, 12, 10 Skin preparation with antiseptic and preoperative antibiotic prophylaxis for clean-contaminated and contaminated surgery have proved efficient for decreasing SSI. 15 SSI, It’s diagnosis consist of the infection with manifestations of pain, oedema, tenderness, redness, dehiscence, or positive culture from material or pus from surgical site. SSI are classified into superficial incisional SSI, deep incisional SSI, & organ/space SSI.16 Triclosan coated sutures reduce the colonization of bacteria 7 & biofilm formation on suture material.17 Sutures in contaminated tissues may enhance penetration of micro organisms in deeper tissues & biofilm formation and this may protect organisms from host defence mechanism. 19, 18, 3 One of the risk factors is the foreign material which includes suture. 16 Commonly isolated pathogens from SSI are Staphylococcus aureus, CONS, Enterococcus species, E.coli & resistant pathogens like MRSA & candida (due to widespread use of broad spectrum anti-microbial agents.) [bailey] Triclosan was developed in 1960 & it is antibacterial as well as antifungal agent used in toothpastes, detergents, hand wash antiseptic solutions, soaps, toys etc.20, 7 It’s use in health industry started in 1972 & has been used in hand rubs, skin antiseptics, ointments, impregnated/coated catheters & sutures.11 Triclosan (2,4,4’-tricloro-2’-hydroxydiphenyl ether) is a broad spectrum biocide, non specifically disrupting the bacterial cell membrane, targeting the Fab I gene which blocks the bacterial fatty acid synthesis through the action of enzyme enoyl-acyl carrier protein reductase (ENR).3 The triclosan is an antiseptic & not an antibiotic hence the risk of resistance is very low. 3 Various studies have been conducted & stated that toxicity due to triclosan are considered low & it showed highly significant results in lowering risk of SSI.21, 11 Triclosan having antimicrobial activity against Gram positive & Gram negative bacteria but less activity against P. aeroginosa.16 In this study we compared in vitro efficacy of triclosan coated polyglactin 910 suture with non – coated suture against common bacteria isolated from SSI.
Aims and Objectives
To compare in vitro efficacy of triclosan coated polyglactin 910 sutures with uncoated sutures against organisms isolated from SSI.
Materials and Methods
Inclusion criteria
All samples received for culture & sensitivity from surgical sites within given period.
Exclusion criteria
All isolates other than surgical site infections.
The study was carried out at Department of Microbiology, MGM Medical College & Hospital Aurangabad, Maharashtra from 2nd June 2017 to 2nd July 2017. In this period there were total 15 samples of SSI, out of these 09 samples were positive for bacterial isolates & 06 samples were sterile.
Table 1
Zone of Inhibition around coated and uncoated suture materials
Isolation & Identification of bacteria from SSI
Samples from SSI were inoculated in Nutrient agar, Blood agar & McConkey’s agar plates, incubated at 370C overnight & isolates were identified in Vitek 2 compact system. We have isolated MRCONS – 2, Acenetobacter baumanii – 2, MRSA – 1, Staphylococcus hemolyticus – 1, Enterobacter cloaceae complex – 1, E.coli – 1, & Klebsiella pnemoniae – 1.
In – Vitro testing of Triclosan coated & uncoated sutures against the bacteria isolated from SSI
We have randomly taken the strains of MRSA, MRCONS, Staphylococcus hemolyticus, E. Coli, Klebsiella, & Acinetobacter species isolated from clinical samples of SSI & these strains were tested against triclosan coated & non coated sutures which are commercially available (Ethicon). Lawn culture of isolated organisms were made on Muller Hinton Agar (MHA) plates by using 0.5 McFarland standard (corresponds to 1.5 x 108 bacteria/ml) 7 of above strains by touching 4 to 5 colonies of each bacterium.16 Similar length of (4cm) of triclosan coated & non coated sutures cut with aseptic precautions & placed on half of inoculated plates each. 1 It is incubated overnight at 370C & examined for zone of inhibition after 48 hr.16 Zone of inhibition were measured perpendicular to mid-point of suture material in millimetre. 7
Results
Isolation & Identification of bacteria from SSI
Total 15 samples of SSI were taken, out of these 09 (60%) samples were positive for bacterial isolates & 06 (40%) samples were sterile, in a single month’s duration. Isolates were MRCONS – 2(22.2%), Acenetobacter baumanii – 2(22.2%), MRSA – 1(11.1%), Staphylococcus hemolyticus – 1(11.1%), Enterobacter cloaceae complex – 1(11.1%), E.coli – 1(11.1%), & Klebsiella pnemoniae – 1(11.1%).
In – Vitro testing of triclosan coated & uncoated sutures against the bacteria isolated from SSI
Each bacterium, was tested against triclosan coated & uncoated suture. The zone of inhibition around triclosan coated & uncoated sutures were measured. Wide zone of inhibition was found against triclosan coated sutures than uncoated sutures. The zone of inhibition against triclosan coated sutures were – for MRSA 13 to 14 mm, for Acenetobacter baumanii 11 mm, for MRCONS 14 to 16 mm, for Staphylococcus hemolyticus it was 15 mm, for Enterobacter cloaceae complex it was 8 mm, and for Klebsiella pnemoniae it was 8 mm. While there were no zone of inhibition against uncoated sutures by all organisms
Discussion
Triclosan coated sutures inhibit in vitro growth of MRCONS, Acenetobacter baumanii, MRSA, Staphylococcus hemolyticus, Enterobacter cloaceae complex, E.coli, & Klebsiella pnemoniae. The clinical efficacy of triclosan had been studied against uncoated sutures. Zone of inhibitions around coated and uncoated sutures were comparable with the study of Sarkar et al, S. Soumya et al and Prachi et al did not found any zone of inhibition around coated sutures in Enterococcus and Pseudomonas species, while as we did not have these isolates we could not have tested these organisms. Various studies depicted that, antimicrobial activity of triclosan coated sutures persisted for 96 hrs, 22 & for up to 7 days in aqueous environment. 23 While we have tested for 48 hrs as Sarkar et al and it is comparable with the findings. SSI commonly occur from commensal organisms such as coagulase negative staphylococci, diphtheroids, Pseudomonas, & Propionibacterium species which are consistently present on patient’s skin. Thus it is assumed that use of triclosan coated sutures could significantly reduce the SSI rate by inhibiting the growth of commensal organisms & thereby reducing the cost & duration of the hospital stay. Enterococcus & Pseudomonas are the exceptional organisms where these triclosan coated sutures were not show inhibition of growth. 3
Conclusion
In vitro antibacterial efficacy of Triclosan coated polyglactin 910 sutures is sufficient to inhibit or reduce the in vitro colonization of the suture materials by MRCONS, Acinetobacter baumanii, MRSA, Staphylococcus hemolyticus, Enterobacter cloaceae complex, E.coli, & Klebsiella pnemoniae compared to uncoated suture materials.
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