Qualitative and Semi Quantitative Culture Assays of Bacterial Bioburden in Chronic Non Healing Superficial Wounds Before and After Electrical Stimulation and Invitro study on the Antibacterial Effects of Electrical Stimulation.

Mahesh Prabhu, S (2010) Qualitative and Semi Quantitative Culture Assays of Bacterial Bioburden in Chronic Non Healing Superficial Wounds Before and After Electrical Stimulation and Invitro study on the Antibacterial Effects of Electrical Stimulation. Masters thesis, Stanley Medical College, Chennai.


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INTRODUCTION : Humans are not germ free. Therefore, health is not absence of bacteria but is kindred to an elegant balance among humans, their resident or transient flora and flora of the environment. The intact skin and the mucous membrane are the most eloquent defenses for humans. Any damage or injury to integument disturbs this bastion and its equilibrium with the bacterial flora. A wound is a breach in the skin and the exposure of subcutaneous tissue following loss of skin integrity provides a moist, warm and nutritive environment that is conducive to microbial colonization and proliferation. Infection occurs when the bacteria accomplish penetration of the subcutaneous tissue and achieve an acute number. Wounds can be broadly categorized as having either an acute or chronic etiology. Irrespective of the nature of the cutaneous injury, acute wounds are expected to heal within a predictable time frame. Chronic wounds result from the disruption of the normal healing process and appear to be struck in the inflammatory phase with accumulation of excessive extra cellular matrix components and matrix proteinases. Each wound needs to be evaluated independently to assess which factors may be at play in disturbing the healing process. Local factors contributing to poor wound healing include infection, tissue hypoxia, repeated trauma, history of irradiation or the presence of necrotic tissue. Systemic factors include diabetes, ageing, malnutrition, obesity, smoking, immunodeficiency and certain medications. In this study, qualitative and semi quantitative aerobic bacterial cultural assay of tissue biopsies from chronic non healing superficial wound patients before and after electrical stimulation is compared with control. In vitro demonstration of the antibacterial effects of electrical stimulation also included in this study. AIMS AND OBJECTIVES : • To isolate and characterize the bacterial agents causing infections in chronic non healing superficial wounds. • Estimation of bacterial bio burden in the chronic non healing superficial wounds by semi quantitative culture assay before and after electrical stimulation. • To compare the effects of electrical stimulation in controlling the bacterial bio burden of chronic wounds with controls • To compare the healing rates of chronic wounds treated with and without electrical stimulation. • Clinico-Microbiological correlation of the effects of electrical stimulation on chronic non healing superficial wounds. • In vitro demonstration of antibacterial effects of electrical stimulation. MATERIALS AND METHODS : Randomized controlled Prospective study. This study was done in department of Microbiology, Stanley medical college, in association with department of plastic surgery, Govt. Stanley Hospital, Chennai. Study Period from June 2008 to May 2009. During this study period, patients with chronic non healing superficial wounds admitted to the department of Plastic surgery with various etiologies were included. Among the 38 patients selected, 36 patients had single ulcer and 2 patients each had two ulcers. All these ulcers were mostly present in the lower limbs except two ulcers which were present in the upper limbs. Out of the 40 wounds from 38 patients, 20 wounds were kept randomly in the study group and another 20 wounds were kept randomly in the control group. Study group- Electrical stimulation treatment was given for a period of 3 weeks. Control group - Without electrical stimulation only saline dressing was given for 3 weeks. None of the group was treated either with antibiotics or topical antiseptics. Inclusion Criteria: Patients with chronic superficial non healing wounds of varying etiology like diabetes, arterial, venous and pressure ulcers which do not heal in the expected time frame(about a month time) with conventional treatment like optimization of nutrition, moist dressings, debridement, infection resolution, repositioning, and off-loading of pressure. Patients of either sex with ages as and above 15 years. Patients who gave written informed consent to undergo this treatment modalities and various investigations. Patients who were not on systemic and topical antibiotics or antiseptics during this study period. Exclusion Criteria: • Patients on either systemic and topical antibiotics or antiseptics. • Malignant ulcer. • Any indication of thrombosis underlying the wound. • Chronic Osteomyelitis • Patients using cardiac pacemaker were excluded from the study. • Pregnant woman. RESULTS : All patients included in the study had wounds in the lower limbs except 2 patients who had wounds in the upper limbs. On analysis of the etiology of chronic wounds in this study, 14 diabetic ulcers; 10 arterial ulcers; 8 venous ulcers; 6 lymphatic ulcers and 2 unstable scars were present. Total number of patients included in this study were 38, among which 28were males (73.7%) and 10 were females (26.3%). Out of them, between 21- 30 years of age there were 5 males and 1 female, between 31-40 years 6 males and 1 female, between 41-50 years 8 males and 2 females, between 51-60 years 4 males and 3 females, between 61-70years 4 males and 2 females and between 71-80 years 1male and 1female. Most of the patients were in the age group between 41-50 yrs. The youngest patient was 23 years of age and the oldest was 76 years. Most of the patients with chronic ulcer were males. Out of 160 direct smears by Gram’s staining, 77smears showed positive screening in the rapid slide smear technique for Quantitative Assessment which was shown to reliably predict a critical microbial load of >1x105CFUs/ gram of tissue if a single or more micro organism was seen in the entire field under oil immersion objective by using 0.2 ml of tissue homogenate. 83 were reported as negative smear. CONCLUSION : The Microbiological profile of the chronic non healing wounds reveals a critical level of bioburden, Biofilm formation the polymicrobial flora, synergistic relationship between microorganisms and the presence of specific pathogens and their toxins all these causes a state of non healing in the chronic wounds . • Importance of quantitative microbiology is well reinforced in that it is not only helps to estimate the bioburden but also useful in the quantitative assessment of various treatment modalities out come. This also gives a clue to the clinician in deciding the timing of wound closure because the critical bacterial load of >105 CFUs /gm of tissue will badly affect the skin graft survival. • In this era of increasing multi drug resistance & hospital acquired infections; chronic non healing wound patients are clearly a high risk group for acquisition, carriage and dissemination of antibiotic resistant organisms to which antibiotic therapy should not be given merely on clinical grounds alone but it must be validated by the qualitative and quantitative microbiological assays. • The electricidal effects of electrical stimulation on the bacterial viability are clearly documented by in vivo & in vitro studies. • The electrical stimulation can be used adjunctively with other standard wound care management to enhance the wound healing.

Item Type: Thesis (Masters)
Uncontrolled Keywords: Qualitative and Semi Quantitative Culture Assays ; Bacterial Bioburden ; Chronic Non healing superficial wounds ; Electrical stimulation ; Invitro Study ; Antibacterial effects ; Electrical Stimulation.
Subjects: MEDICAL > Microbiology
Depositing User: Subramani R
Date Deposited: 16 Aug 2017 00:38
Last Modified: 16 Aug 2017 03:11
URI: http://repository-tnmgrmu.ac.in/id/eprint/1789

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