Agneza Dešić-Brkić

Cecilija Žilih-Ostojić

Gorana Dokuzović

Mirna Tomljanović-Veselski

Zdenka Topolovac

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Colonization of Venous Leg Ulcers by MicroorganismsMirna Tomljanović-Veselski, Cecilija Žilih-Ostojić, Zdenka Topolovac, Agneza Dešić-Brkić, Gorana DokuzovićDepartment of Dermatology and Venereology, Dr. Josip Benčević General Hospital, Slavonski Brod, CroatiaCorresponding author:Mirna Tomljanović-Veselski, MD, MSDepartment of Dermatology and VenereologyDr. Josip Benčević General Hospital Andrije Štampara 42HR-35000 Slavonski Brod  Croatia mirna.tomljanovic-veselski@sb.htnet.hrReceived: April 10, 2004.Accepted: December 9, 2004.SUMMARY The aim of the study was to identify the microorgan-isms that most commonly colonize leg ulcers. The study included 70 patients of both sexes, aged 31-85 years. There were 49 (70%) female and 21 (30%) male patients, mean age 69.16 and 61.62 years, respectively. Nineteen different types of microorganisms were isolated in study patients: one in 18, two in 38, and three pathogens in 13 patients. Only one of study patients had four mi-croorganisms isolated at the time. The most common microorgan-isms were Pseudomonas aeruginosa found in 25 and Streptococ-cus aureus in 19 patients. KEY WORDS: venous leg ulcers; colonization, microorganism; Pseudomonas aeruginosa; Staphylococcus aureusINTRODUCTION Venous hypostatic ulcer is an open wound, usually located on the lower leg skin damaged by chronic venous stasis. Chronic venous hyperten-sion with consequential cutaneous capillary bed distention and increased capillary wall permeabili-ty plays a major role in the development of venous ulcer (1-3). The prevalence of venous hypostatic ulcer in the population has been estimated to 1% (4). Chronic wounds are not sterile as they are usually colonized but not necessarily infected by microorganisms, implying that antibacterial treat-ment may not always be required. In case of wound infection, pain and inﬂammation of the surround-ing tissue occur, accompanied by pronounced ex-udation and suppuration, occasionally with fever and lymphadenitis. Although the process remains localized, healing of the wound is retarded. Staph-yloccocus aureus, alone or in combination with other gram-negative bacteria, is the bacterium most commonly isolated in venous leg ulcers (5).  PATIENTS AND METHODS The study included 70 patients (49 female and 21 male) aged 31-85, with venous leg ulcers, hos-pitalized at Department of Dermatology and Ve-nereology, Dr. Josip Benčević General Hospital, Slavonski Brod. Wound swab was obtained after 24 hours of saline application. The specimen was obtained from the wound edge towards healthy skin or from the deepest part of the wound ex-pected to contain the highest number of patho-gens. The specimen was immediately transferred to Laboratory of Microbacteriology, Public Health Institute of the Brod-Posavina County for analy-sis. Specimens were put on a solid medium (blood agar and Salmonella Shigella Agar SS-agar), and on a liquid medium (thioglycolate medium, ﬂuid). The specimen was incubated in aerobic condi-tions, thermo status, for 18-24 hours in an atmo-sphere with 5%-10% CO2 at 35° C. History data showed the patients had not been taking any par-enteral, per os or topical antimicrobial therapy for a week before the study.RESULTS The study included 70 patients, mean age 65.39 (age range 31-85) years. There were 49 (70%) female and 21 (30%) male patients, mean age 69.16 and 61.62 years, respectively (Figs. 1 Acta Dermatovenerol Croat  2005;13(2):104-107 CLINICAL ARTICLE104ACTA DERMATOVENEROLOGICA CROATICAand 2). The largest number of patients were in the 7th and 8th decade of life. The duration of venous leg ulcers was found to considerably vary (Fig. 3). A total of 19 different pathogens were isolated in 155 isolates obtained from study patients (Table 1). Pseudomonas aeruginosa was the most com-mon pathogen isolated in 25 patients, followed by Staphylococcus aureus found in 19, and Staphy-lococcus epidermidis, Serratia marcescens and Pseudomonas spp. in 16 patients each (Fig. 4). Less commonly isolated pathogens were Entero-coccus spp., Acinetobacter, Proteus vulgaris, En-terobacter spp., Klebsiella pneumoniae, Providen-cia spp., Klebsiella spp. and Citrobacter spp. Ulcers are usually contaminated by sev-eral pathogens. In our group, a single pathogen was isolated in 17 patients, whereas two patho-gens were isolated in 38, three pathogens in 13, and four pathogens in only one patient (Fig. 5). DISCUSSION Chronic venous ulcers are usually colonized by microorganisms, however, wound infection with the isolated pathogens is extremely rare and ac-companied by a typical clinical picture. None of our patients had wound infection. Pseudomonas aeruginosa is the agent most commonly isolated from venous ulcers, followed by Staphylococ-cus aureus, Staphylococcus epidermidis, Ser-ratia marcescens, Proteus spp., etc. Eriksson et al. (5) report on Staphylococcus aureus, and Schraibmann (6) on gram-negative microorgan-isms as the most commonly isolated pathogens. Pathogen                 nPseudomonas aeruginosaStaphylococcus aureusStaphylococcus epidermidisSerratia marcescensPseudomonas spp.Acinectobacter spp.DiphtheroidsStreptococcus spp.Streptococcus β-hemolytic group GProteus mirabilis Morganella morganiiEscherichia coliEnterobacter spp.Klebsiella pneumoniaeKlebsiella spp.Providencia spp.Proteus vulgarisCitrobacter spp.Enterococcus spp. 25191616161212655433332221Table 1. Number of pathogens isolated in study patients (N=155)Figure 1. Sex distribution of pathogens isolated in study patients.Figure 2. Age distribution of pathogens isolated in study patients. Normal skin ﬂora consists of a great variety of bacteria, fungi and protozoa. The composition of normal skin ﬂora depends on the patient’s general condition, age, pregnancy, nutritional status, per-sonal hygiene, and living conditions. Normal skin ﬂora usually contains the aerobes Staphylococ-cus epidermidis, Staphylococccus saprophyticus, Streptococcaceae and Peptococcaceae, and the anaerobes diphtheroids (7). Staphylococcus aureus belongs to the family of gram-positive cocci, and is characterized by fast and easy development of resistance to antibiotics. Staphylococcus aureus produces many enzymes and exotoxins involved in the pathogenesis of in-Figure 3. Distribution patients according to ulcer durationTomljanović-Veselski et al:    Acta Dermatovenerol CroatColonization of leg ulcers with microorganisms  2005;13(2):104-107105Figure 1. Sex distribution of pathogens isolated in study patients. 70%30%male femaleFigure 2. Age distribution of pathogens isolated in study patients. 452202460 5 10 15 20 2530-4041-5051-6061-7071-8081-90agenumberFigure 3. Distribution patients according to ulcer duration 25201051 180510152025301 5 10 15 20 25 30Ulcer duration (yrs)ACTA DERMATOVENEROLOGICA CROATICAfections. The characteristic staphylococcal infec-tions are abscess, furuncle, carbuncle, wound in-fection, impetigo contagiosa and SSSS syndrome (8). Staphylococcus aureus is a common cause of nosocomial infections, especially in immunocom-promised patients (8). Pseudomonas aeruginosa is a gram-negative anaerobic bacterium. Although a usual saprophyte in humans, it rarely causes infection in immunocom-petent, normal individuals. The infection caused by this microorganism is mostly associated with a fail-ure in the body’s mechanisms of defense, which may imply disruption of a physical barrier such as skin. Pseudomonas aeruginosa shows high afﬁnity for skin defects, including superinfection, especial-ly in hospitalized patients. The infection caused by this pathogen is characterized by blue-green dis-coloration and typical malodor. This infection may remain localized, however, fulminant spread of the infection has also been described (9). Besides these most common causative agents of chronic wound contamination, those less fre-quently observed include Enterobacteriaceae, Escherichia coli, Klebsiella and Proteus, which were also found in our study patients (10). The rate of isolation of these pathogens is by far lower. Apart from Staphylococcus aureus and Pseudo-monas aeruginosa, Staphylococcus epidermidis was most commonly detected in our patients, fol-lowed by Serratia marcescens, diphtheroids and Pseudomonas spp. Acinetobacter spp., group G β-hemolytic streptococci, Proteus vulgaris, Entero-bacter spp., Streptococcus spp., Proteus mirabi-lis, etc. are extremely rarely observed, and in our study were isolated in one patient each (Table 1). In physiologic conditions, different bacteria colonize body surface. A low count of pathogenic bacteria is not associated with an increase in the rate of inﬂammation, however, high colonization may lead to inﬂammation. The presence of Staph-ylococcus aureus count of 105-106/mm2 has been described as sufﬁcient to induce infection in stan-dard conditions (10).  The initial stage of the infection proceeds free from any clinical signs of the disease, how-ever, the bacteria keep penetrating the body where they multiply at a fast rate. Our patients showed no signs of wound infection or erysip-elas, thus topical therapy was used in most pa-tients. The subsequent course, i.e. development of infection, depends on the infectiosity, virulence and invasiveness of the agent, and on the gen-eral condition and immune status of the patient. Figure 4. Percentage of pathogens isolated in study patients Swab sampling for bacteriologic testing is not necessary in routine wound care. It is only recom-mended when one or more signs or symptoms indicative of wound infection are present, e.g., cel-lulitis, elevated temperature, pain, skin redness, lymphangitis, or ulcer enlargement. The diagnosis may be confounded by acute dermatitides such as contact dermatitis with erythema and wound en-largement. The management of venous leg ulcers includes systemic antibiotic therapy according to antibiotic sensitivity report. Cellulitis, a common complica-tion of venous leg ulcers, may be mistaken for noninfective erythema and edema that frequently surround the ulcer. Cellulitis is accompanied by the signs of tension or pain, lymphangitis, fever, nausea and leukocytosis (11,12).CONCLUSION Venous ulcers are chronic wounds that are ob-ligatorily colonized by microorganisms. The pres-ence of microorganisms need not imply an infec-tion. In the absence of the clinical signs of infec-tion, there is little evidence that wound healing is retarded by bacteria. Figure 5. Pathogen distribution according to num-ber of samplesTomljanović-Veselski et al:    Acta Dermatovenerol CroatColonization of leg ulcers with microorganisms  2005;13(2):104-10710616.13%12.26%10.32%10.32%10.32%7.74%7.74%2.58%22.58%Pseudomonas aeruginosa Staphylococcus aureusStaphylococcus epidermidis Serratia marcescensPseudomonas spp. Acinetobacter spp.Diphtheroids Morganella morganiiOther16.13%12.26%10.32%10.32%10.32%7.74%7.74%2.58%22.58%Pseudomonas aeruginosa Staphylococcus aureusStaphylococcus epidermidis Serratia marcescensPseudomonas spp. Acinetobacter spp.Diphtheroids Morganella morganiiOtherFigure 5. Pathogen distribution according to number of samples 17381310102030401 samples 2 samples 3 samples 4 samplesACTA DERMATOVENEROLOGICA CROATICA References1. Budimičić D. Bolest krvnih žila i hemoragijske bolesti kože. In: Lipozenčić J, editor. Dermatovenerologija. Zagreb: Naklada Zadro; 1999. p. 190-6.2. Budimčić D. Bolest krvnih i limfnih žila. In: Dobrić I, et al., editors. Dermatovenerologija. Zagreb: Grafo-plast; 1994. p. 235-46.3. Hofman RD. Oedema and the management of ve-nous ulcers: update on the physiology of oedema and its effects on healing in venous ulceration. J Wound Care 1998;7:334-45.4. Callam MJ, Ruckley CV, Harper DR, Dale JJ. Chronic ulceration of the leg: extent of the problem and provision of care. Br Med J 1985;290:1855-6.5. Eriksson G, Eklund AE, Kallings LD. The clinical signiﬁcance of bacterial growth in venous leg ul-cers. Scand J Infect Dis 1984;16:175-80.6. Schraibmann IG. The signiﬁcance of β-haemolytic streptococci in chronic leg ulcers. Ann R Coll Surg 1990;72:123-4.7. Niedner R, Schopf E. Wound infections and antibac-terial therapy. In: Westerhof W, editor. Leg ulcers. Amsterdam, London: Elsevier; 1993. p. 193-303.8. Vukadinović MV. Staﬁlokoki. In: Kalenić S, Mlinarić-Missoni E, editors. Medicinska bakteriologija i mikrobiologija. Zagreb: Prehrambeno tehnološki inžinjering; 1995. p. 192-8.9. Vranješ J. Pseudomonas acinetobacter. In: Kalenić S, Mlinarić-Missoni E, editors. Medicinska bakte-riologija i mikrobiologija. Zagreb: Prehrambeno tehnološki inžinjering; 1995. p. 237-46.10. Brook I. Secondary bacterial infections complicating skin lesions. J Med Microbiol 2002;51:808-1012.11. Elder DM, Kenneth EG. Venous disease: how to heal and prevent chronic leg ulcers. Geriatrics 1995;8:30-6.12. Douglas WS, Simpson NB. Guidelines for man-agement of chronic venous leg ulceration. Report of a multidisciplinary workshop. Br J Dermatol 1995;132:446-52.Tomljanović-Veselski et al:   Acta Dermatovenerol CroatColonization of leg ulcers with microorganisms  2005;13(2):104-107107For skin protection from cold, windy and wet weather, use Nivea cream.From the Nivea collection of Zlatko Puntijar (1929)

Colonization of Venous Leg Ulcers by Microorganisms

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