[Atypical agents of wound infection and targeted samples]

All open wounds are primarily contaminated and subsequently colonized by microorganisms, predominantly bacteria. Only about 30% of chronic wounds are also infected. Factors which favor the development of infection are the following: large quantity of bacteria, presence of virulence factors, their quantity and number, predominantly the synergy of aerobic and anaerobic bacteria, and formation of biofilm. Common agents of infection of acute and chronic wounds are Staphylococcus aureus, MRSA, Streptococcus beta-haemolyticus, Pseudomonas aeruginosa, Bacteroides spp., and Candida albicans. Difference between acute and chronic wound is in the predominance of individual agents, with an observation that Staphylococcus aureus is predominant in both cases. Atypical agents of chronic wound infection are rare, unusual, not found in the area in which we live, not proven by standard microbiological methods, but molecular methods are needed instead. They are predominantly opportunists, varying in the expression of virulence factors, or they have changed their phenotype characteristics and are not the agents of primary wound infections. They are the agents of secondary infections. Atypical agents of the chronic wound infection are diverse, from the anaerobe group, Peptoniphilus spp., Anaerococcus spp., Bacteroides ureolyticus, Finegoldia magma, the group of gram positive rods of the Corynebacterium genus, the group of bacteria from aquatic environment Mycobacterium fortuitum complex, and Vibrio alginolyticus. The targeted samples are biopsy sample as the "gold standard" and/or aspirate, when a significant quantity of exudate is present. Targeted samples are obligatory when there is a progression and decomposition of the base of the wound, increase in the size or depth of the wound, isolation of multiresistant microbes, or absence of clinical response to empirical antimicrobial therapy. In the diagnosis of opportunistic pathogens or atypical agents of chronic wound infection, it is necessary to be thorough, meticulous, and conduct revision of the patient, diagnosis, treatment and samples. Crucial for the detection of the agents atypical wound infection is discussion and agreement with clinical microbiologist. Essential for the quality diagnosis is decontamination of the wound before taking targeted samples. The targeted sample is biopsy specimen as the "gold standard", less frequently aspirate, depending on the quantity and content of the wound. Swab as a sample is not recommended. If there is no other choice, only exceptionally surface swabs may be taken, but only under the following conditions: decontamination of the wound with the application of Levine's or Z-technique of taking of swabs.