Volume 8 Supplement 1

The College of Podiatry Annual Conference 2014: meeting abstracts

Open Access

Diabetic foot ulcer wound fluid: the effects of pH on DFU bacteria and infection

  • Carla McArdle1,
  • Katie Lagan1,
  • Sarah Spence2 and
  • David McDowell2
Journal of Foot and Ankle Research20158(Suppl 1):A8

https://doi.org/10.1186/1757-1146-8-S1-A8

Published: 20 April 2015

Background

Foot ulceration is one of the most significant complications of diabetes, and will affect 15-20% of people with diabetes at some point in their lives. Such ulcers frequently become infected with very serious sequelae which can often lead to amputation making diabetes is the most common cause of lower extremity amputations. Infections cause increased morbidity (and/or mortality) which means that they represent significant clinical events, requiring immediate attention in relation to local and systemic complications thus requiring well-coordinated management. Unfortunately diabetic foot infections (DFI) frequently fail to display overt signs and symptoms of infection including purulence, erythema, pain, tenderness, warmth and induration. This makes it difficult for clinicians to detect infection, and to make timely interventions to limit the highly undesirable consequences of DFIs. Alternative means of rapidly diagnosing infection are urgently required.

Aim

To determine if the presence/absence of microorganisms, and ultimately the presence of infection, are affected by diabetic foot ulcer (DFU) wound fluid pH.

Methods

DFUs of patients (n=55) were assessed in terms of presence/absence of clinical signs of infection as part of their routine clinical appointment at a High-Risk Foot Clinic. Wound fluid samples were also collected from the DFUs by filter paper absorption and/or pipette aspiration. The pH of samples was determined using a micro-electrode pH meter. Bacteria in the wound fluid were recovered by 24hr incubation in Tryptone Soya Broth, and plating on selective agars which included; MacConkey Agar (Staphylococcus spp, Enterobacter spp), Pseudomonas Agar Base (Pseudomonas spp). Chromocult Agar (E. Coli, Coliforms), Baird Parker Agar (Staphylococcus spp) and Columbia Blood Agar (Streptococcus spp). Organisms identified as Staphylococcus Aureus cultured on Muller Hinton Agar and and MRSA present detected using Oxacillin and Cefoxitin antibiotic disks.

Results

Sample pH values ranged from 6.2 to 8.5. Recovered bacteria included Pseudomonas, Enterobacter, Staphylococcus and Streptococcus spp. Correlations were observed between DFU fluid pH values, the presence/absence of these species and the presence/absence of clinical signs of infection. This presentation will discuss the potential clinical implications of these findings.

Conclusions

pH conditions within DFUs influence bacterial presence/absence in these wounds. pH conditions also influence the presence/absence of clinical signs of infection. Timely monitoring of DFU fluid pH could enhance clinicians’ abilities to rapidly detect and more effectively manage DFU infections. An improved understanding of the interactions between DFU pH and bacterial metabolism may identify ways to limit the duration and wider impact of DFU infections.

Governance compliance statement - Ethical approval and research governance has been granted for the clinical study to take place and all research governance procedures are being adhered to during the completion of the study.

Authors’ Affiliations

(1)
Centre for Health and Rehabilitation Technologies (CHaRT), School of Health Sciences, University of Ulster
(2)
School of Health Sciences, University of Ulster

References

  1. Amputee Statistical Database for the United Kingdom, 2007: Lower Limb Amputations Diabetes UK. The British Diabetic Association. 2011, [http://www.diabetes.org.uk]Google Scholar
  2. International Diabetes Federation, (2011) Global Diabetes Plan 2011-2021. [http://www.idf.org/sites/default/files/Global_Diabetes_Plan_Final.pdf]
  3. Jeffcoate W, Lipsky BA, Berendt AR, Cavanagh PR, Bus SA, Peters EJ, et al: Unresolved issues in the management of ulcers of the foot in diabetes. Diabetes Medicine. 2008, 25 (12): 1380-1389. 10.1111/j.1464-5491.2008.02573.x.View ArticleGoogle Scholar
  4. Lavery LA, Armstrong DG, Wunderich RP, Wendel CS, Lipsky BA: Risk factors for foot ulcerations in individuals with diabetes. Diabetes Care. 2006, 29 (6): 1288-1293. 10.2337/dc05-2425.View ArticlePubMedGoogle Scholar

Copyright

© McArdle et al; licensee BioMed Central Ltd. 2015

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.

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