Distribution and Antibiotic Resistance Patterns of Pathogenic Bacteria in Patients With Chronic Cutaneous Wounds in China

Background: To determine the distribution and antimicrobial susceptibility pattern of pathogenic bacteria in patients with chronic cutaneous wounds on a national scale.

Methods: A retrospective study was conducted using the data recorded between January 1, 2018 and January1, 2020 in 195 hospitals across China. After screening the data, 815 patients with chronic wounds were finally analyzed. The data collected included information about the patients' general condition and local cutaneous wound assessments, especially microbial culture and antibiotic susceptibility tests. The analyses were performed using SPSS Version 26.

Results: The study included 815 patients (290 [35.6%] females; 63 [50–74] years). The most common causes of chronic cutaneous wounds were diabetes (183, 22.5%), infection (178, 21.8%), and pressure (140, 17.2%). Among these, 521(63.9%) samples tested yielded microbial growth, including 70 (13.4%) polymicrobial infection and 451 (86.6%) monomicrobial infection. The positive rate of microbial culture was highest in wound tissue of ulcers caused by infection (87.6%), followed by pressure (77.1%), diabetes (68.3%), and venous diseases (67.7%). Bates-Jensen wound assessment tool (BWAT) scores >25 and wounds that lasted for more than 3 months had a higher positive rate of microbial culture. BWAT scores >25 and wounds in the rump, perineum, and feet were more likely to exhibit polymicrobial infection. A total of 600 strains were isolated, of which 46.2% (277 strains) were Gram-positive bacteria, 51.3% (308 strains) were Gram-negative bacteria, and 2.5% (15 strains) were fungi. The most common bacterial isolates were Staphylococcus aureus (29.2%), Escherichia coli (11.5%), Pseudomonas aeruginosa (11.0%), Proteus mirabilis (8.0%), and Klebsiella pneumoniae (5.8%). The susceptibility tests showed that 116 cultured bacteria were Multidrug resistant (MDR) strains. The resistance rates of S. aureus were 92.0% (161/175) to penicillin, 58.3% (102/175) to erythromycin, and 50.9% (89/175) to clindamycin. Vancomycin was the most effective antibiotic (0% resistance rate) against all Gram-positive bacteria. Besides, the resistance rates of E. coli were 68.1% (47/69) to ampicillin, 68.1% (47/69) to ciprofloxacin, 60.9% (42/69) to levofloxacin. However, all the isolated Gram-negative bacteria showed low resistance rates to tigecycline (3.9%) and amikacin (3.6%).

Conclusions: The distribution of bacteria isolated from chronic cutaneous wounds varies with the BWAT scores, causes, duration, and the location of wounds. Multidrug resistance is a serious health issue, and therefore antibiotics used in chronic wounds must be under strict regulation. Our findings may help clinicians in making informed decisions regarding antibiotic therapy.