Monitoring and Molecular Characterization of Staphylococcus aureus Isolated from Chronic Wounds.

OBJECTIVE: Researchers analyzed chronic wounds treated with 2% hydrogel to determine whether the presence of methicillin-resistant Staphylococcus aureus (MRSA) is related to the presence of clinical signs of infection. METHODS: Thirty-five patients were recruited for this descriptive study using a quantitative approach. Staphylococcus aureus was identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry. Antibiotic susceptibility was determined using a disk diffusion test according to Clinical and Laboratory Standards Institute standards. Polymerase chain reaction, pulsed-field gel electrophoresis, and multilocus sequence typing were performed. Statistical analyses were performed using Spearman correlation coefficients for the variables MRSA and clinical signs of infection. MAIN OUTCOME MEASURES: The identification of MRSA or methicillin-sensitive S aureus (MSSA), presence or absence of an infection in the wound, and molecular characterization of bacteria were measured. MAIN RESULTS: Of the 35 patients analyzed, 8 (22.9%) were classified as having an infection in their wounds. Spearman ρ indicated a strong positive correlation between the increase in the number of clinical signs of infection and MSSA (P =.84), but only a moderate positive correlation with MRSA (P =.60). The S aureus clonal pattern was unique for each of the major bacteria isolated. Global MRSA sequence-type clones (ST-1 and ST-72) were detected in 2 patients. CONCLUSIONS: Compared with those colonized by MSSA, chronic wounds colonized by MRSA did not display a strong correlation with the presence of a greater number of clinical signs of infection.

Prevalence, Antimicrobial Susceptibility, and Clonal Diversity of Pseudomonas aeruginosa in Chronic Wounds.

PURPOSE: Our purposes in this study were to (1) identify Pseudomonas aeruginosa strains collected from swabs of chronic wounds, (2) evaluate the susceptibility of P. aeruginosa strains to various antimicrobials, (3) detect the presence of virulence factors exoenzyme S (exoS) and exoenzyme U (exoU) in P. aeruginosa strains, and (4) evaluate wound colonization by P. aeruginosa via pulsed-field gel electrophoresis (PFGE). DESIGN: Descriptive research using a quantitative approach. SAMPLE AND SETTING: Swabs from 43 adults with chronic wounds treated in an outpatient setting in Niterói City, Brazil, were included using convenience sampling. METHODS: Swabs were collected at 2 points during treatment, 30 to 45 days apart. P. aeruginosa isolates were identified using matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry. Antimicrobial susceptibility testing was performed using the disk diffusion method. The presence of exoS and exoU genes was evaluated using polymerase chain reaction. Genotyping diversity was determined through PFGE. RESULTS: Forty-eight P. aeruginosa isolates were detected in chronic wounds, and 3 were multidrug resistant (6%). Resistance to aztreonam and ciprofloxacin was observed in 48% and 27% of isolates, respectively. The presence of the exoS gene was verified in 54% of isolates, and 27% were positive for the exoU gene. In most wounds, P. aeruginosa strains had the same genetic characteristics at the 2 time points analyzed, indicating that the wound beds remained colonized. CONCLUSIONS: P. aeruginosa was present in 75% of tested chronic wound samples, and the same clones persisted for more than 1 month. In addition, most bacteria contained virulence genes that were associated with high potential to establish infection. The use of silver in chronic wounds may be associated with multidrug resistance in P. aeruginosa; therefore, it is important to avoid colonization by these bacteria.

Ciprofloxacin-Resistant Kerstersia gyiorum Isolated From a Chronic Wound in Brazil: A Case Report.

The presence of Kerstersia gyiorum in lower leg wounds has been reported in case studies from several countries. OBJECTIVE: This study evaluated the antimicrobial susceptibility profile of K gyiorum isolated from a chronic wound. METHODS: An 85-year-old woman with chronic venous insufficiency presented to an intermediate care unit in Niteroi City, Rio de Janeiro, Brazil, with an instep chronic wound of 14 cm² with wound duration of 6 months. K gyiorum was identified by matrix-assisted laser desorption ionization-time of flight, confirmed by 16S rRNA partial sequence analysis, and classified as resistant for ciprofloxacin by reagent strips(minimum inhibitory concentration [MIC] = 32 µg/mL) and the broth macrodilution method (MIC = 8 µg/mL). Intermediate resistance for ciprofloxacin was verified by microscan (MIC = 2 µg/mL). CONCLUSION: The authors identified the first, to their knowledge, lower leg wound with K gyiorum in Brazil and verified that it was ciprofloxacin resistant.