Wound infection continues to be problematic in clinical practice where empirical treatment of infection is routine. A wound is defined as any injury that damages the skin and therefore compromises its protective function. A retrospective study to determine the causative organisms of wound infections and their antimicrobial susceptibility pattern in the Hopes hospital and laboratory, Nnewi, Anambra State of Nigeria. Records of wound swabs collected from 60 patients with high suspicion of wound infection were analysed. Smears of the wound swabs were inoculated on appropriate media and cultured. Bacterial isolates were Gram stained and microscopically examined. Biochemical and sugar fermentation tests were done to identify pathogen species. The Kirby-Bauer disk diffusion method was used for antibiotic testing. Prevalence of wound infection was 83.3%. Most bacteria were Gram negative rods with Klebsiella pneumoniae being the most prevalent pathogen isolated. The bacterial isolates exhibited a high degree of resistance to antibiotics tested (50% – 100%). All isolates were resistant to zinnacef and tarivid and almost all the isolates were susceptible to streptomycin. There was a significant association between the age group and the aetiological agent. Sex did not exert any effect on the prevalence, aetiological agent or antimicrobial resistance pattern. I suggest a multidisciplinary approach to wound management, routine microbiological surveillance of wounds, rational drug use and institution of strong infection control policies.
TABLE OF CONTENTS
Table of contents v
List of tables viii
List of figure ix
Literature review 4
Materials and methods 11
- Materials for the study 11
- Area of the study 11
- Sampling Area 11
- Sample used 11
- Inclusion criteria 11
- Exclusion criteria 12
- Number of Samples 12
- Sample Collection 12
- Time of collection 12
- Site of the wound 12
- Types of wound 12
- Media used for study 12
- Preparation of media 13
- Control 13
- Inoculation of wound sample 14
- Incubation of inoculated plates 14
- Subculturing of colonies 14
- Preservation of pure cultures 15
- Identification of isolates 16
- Microscopic identification 16
- Biochemical tests 17
- Antisusceptibility testing 21
LIST OF TABLES
- Age distribution of patients with significant bacterial growth 24
- Distribution of isolated organisms within age groups 25
- Distribution of isolated organisms amongst gender 26
- Frequency of wound types 27
- Frequency of the wound sites 28
- Frequency of bacterial isolates from the wound swabs 29
- Frequency of micro organism according to wound types 30
- Sugar fermentation results of isolated organisms 31
- Biochemical results of the isolated organisms 32
- Antisusceptibility pattern of isolated organism 33
LIST OF FIGURES
Figure 1 Frequency of bacterial isolates from wound swabs 30
Appendix 1: Statistical analysis
1.1 Distribution of isolated organisms within age groups 39
1.2 Distribution of isolated organisms amongst gender 42
1.3 Frequency of wound types 45
1.4 Frequency of the wound sites 47
- Frequency of micro organism according to wound types 49
Appendix 2: Materials and methods 51
The primary function of intact skin is to control microbial population that live on the skin surface and to prevent underlying tissue from becoming colonized and invaded by potential pathogens (Ndip et. al., 2007). Exposure of subcutaneous tissue following a loss of skin integrity (i.e. wound) provides a moist, warm and nutritious environment that is conducive to microbial colonization and proliferation.
A wound is defined as any injury that damages the skin and therefore compromises its protective function. An acute wound is generally caused by external damage to the skin, including abrasions, minor cuts, lacerations, puncture wounds, bites, burns and surgical incisions. A wound is a breakdown in the protective function of the skin; the loss of continuity of epithelium, with or without loss of underlying connective tissue (Leaper and Harding, 1998). Wounds can be accidental, pathological or post operative. All wounds contain bacteria but majority of the wounds do no get infected. There are many variables that can promote wound infection when there is a discontinuity of skin barrier. This include both host and organism related factors like bacterial load and type, immune competence of host co-morbid like diabetes mellitus, etc (Mir et. al., 2012). An infection of this breach in continuity constitutes wound infection. Wound infection is thus the presence of pus in a lesion as well as the general or local features of sepsis such as pyrexia, pain and indurations.
Wound infections are one of the most common hospital acquired infections and are an important cause of morbidity and account for 70-80% mortality (Gottrup et al., 2005; Wilson et al., 2004). Wound infections can be caused by different groups of micro organisms like bacteria, fungi and protozoa. However, different micro organisms can exist in polymicrobial communities especially in the margins of wounds and in chronic wounds (Percevil and Bowler, 2001). Infection is one of the major causes of morbidity and mortality in hospitalized patients irrespective of the cause as it delays healing (Pondei et al., 2013). It also causes longer hospital stay and increased expenses. In order to recognise early signs and symptoms of infections in a wound, whether complicated or not, skilled and vigilant team of doctors and paramedical staff is required (Moore and Romanelli, 2006).
Wound infections have been a problem in the field of surgery for a long time. Advances in control of infections have not completely eradicated the problem because of development of resistance. Antimicrobial resistance can increase complications and costs associated with procedures and treatment. An infected wound complicates the postoperative course and results in prolonged stay in the hospital and delayed recovery. Most bacteria live on our skin, in the nasopharynx, gastrointestinal tract and other parts of the body with little potential for causing disease because of first line defence within the body. Surgical operation, trauma, burns, diseases, nutrition and other factors affect these defences. The skin barrier is disrupted by every skin incision, and microbial contamination is inevitable despite the best skin preparation.
Knowledge of the causative agents of wound infection in a specific geographic region will therefore will be useful in the selection of antimicrobial for empirical therapy. Antimicrobial resistance can increase complications and costs associated with procedures and treatment (Anguzu and Olila, 2007).
Statement of Research Problem
Wound infections have been a problem in the field of medicine for a long time. The presence of foreign materials increases the risk of serious infection even with relatively small bacterial inoculums (Rubins, 2006). Advances in control of infections have not completely eradicated the problem because of development of resistance. Antimicrobial resistance can increase complications and costs associated with procedures and treatment.
Aim of the study
This study was therefore designed to determine the aetiological agents of the wound infections and their antimicrobial susceptibility pattern.