The clinical efficacy of two semi-quantitative wound-swabbing techniques in identifying the causative organism(s) in infected cutaneous wounds

Abstract

A prospective randomised controlled trial of two paired wound-swabbing techniques (Levine versus Z) was conducted to establish which method was more effective in determining the presence of bacteria in clinically infected wounds. The Levine technique involves rotating the wound swab over a 1-cm(2) area of the wound; the Z technique involves rotating the swab between the fingers in a zigzag fashion across the wound without touching the wound edge. Fifty patients were recruited into the study with acute (42%) and chronic wounds (58%). Overall, the Levine technique detected significantly more organisms than the Z technique (P≤ 0· 001). When acute and chronic wounds were analysed separately, the Levine technique again detected more organisms in both acute (P≤ 0· 001) and chronic wounds (P≤ 0· 001). We conclude that the Levine technique is superior to the Z technique and this result may be because of the Levine technique's ability to express fluid from the wound bed and thereby sampling a greater concentration of microorganisms from both the surface and slightly below the surface of the wound.

Swab Versus Biopsy for the Diagnosis of Chronic Infected Wounds

“…Subsequently, a continuous monthly database alert was set up, using the same search strategy and inclusion criteria, leading to 2 more published articles beyond the date of the original time frame and bringing the final selection to 6 articles. 42,43 …”

Molecular and Culture-Based Assessment of the Microbial Diversity of Diabetic Chronic Foot Wounds and Contralateral Skin Sites

“…Data in Tables 2 and 3 show semiquantitative growth data from chronic wound tissue samples and intact-skin swabs, respectively. Tissue samples were grouped based on the isolation or absence of pathogenic wound organisms (1,22,25). From the organisms cultured, S. aureus was the only overt pathogen identified using the defined assessment parameters (1,22,25).…”

“…Tissue samples were grouped based on the isolation or absence of pathogenic wound organisms (1,22,25). From the organisms cultured, S. aureus was the only overt pathogen identified using the defined assessment parameters (1,22,25). Intact-skin swabs produced comparatively low numbers of skin-associated bacteria, with no sample producing moderate to heavy growth of any bacterial isolate.…”

“…Residual samples of homogenized tissue were archived at Ϫ80°C for bacterial DNA extraction. Bacterial species isolated from the four quadrants were reported as scant (Ͻ10 colonies), light (first quadrant), moderate (second quadrant), or heavy (third-fourth quadrant) growth according to methods outlined and validated by Angel et al (1) and Healy and Freedman (22). Bacterial identification was based upon colony morphology, Gram staining, catalase reaction, latex coagulase reaction tests, Lancefield group reaction to identify ␤-hemolytic strepto- a Commonly isolated wound-associated pathogens which may be indicative of infection (25).…”

Management of venous leg ulcers: Clinical practice guidelines of the Society for Vascular Surgery® and the American Venous Forum

“…119,120 Deep wound tissue cultures should be reserved for wounds colonized with multiple micro-organisms when the bacterial pathogen is not clear from surface cultures, for biofilm infections, or for recurrent or persistent infection despite appropriate antimicrobial therapy. [121][122][123][124][125] When VLUs do not respond to standard wound and compression therapy, contributing factors should be considered, including infection and possible misdiagnosis. Whereas evidence does not support an absolute time frame, most evidence and clinical practice guidelines suggest tissue biopsy considerations within 4 to 6 weeks of nonresponsiveness to standard treatment.…”