[Clinical distribution and antimicrobial resistance analysis of 754 pathogenic bacteria in diabetic foot infection]

Abstract

Objective: To explore the microbiological profiles and antibiotic susceptibility patterns of organisms isolated from diabetic foot ulcers so as to provide selection rationales of antibiotics.

Methods: A retrospective study was conducted on the microbiological profiles and antibiotic susceptibilities in 754 strains of pathogens isolated from 519 patients with diabetic foot ulcers at our hospital from January 2010 to August 2013. The inter-group data were compared by Chi-square test.

Results: There were 322 (62.0%) males and 197 (38.0%) females. Their mean age was (67.7 ± 12.3) (30-93) years, duration of diabetes 10 (0-40) years, duration of lower-limb lesion 1.0 (0.0-72.0) months and HbA1c (9.09% ± 2.28%). Among 444 (85.5%) cases, a total of 754 strains of pathogens were isolated. Gram-positive aerobes were the most frequently isolated (47.3%, 357 strains) and followed by gram-negative aerobes and fungus (40.3% vs 12.3%, 304 vs 93 strains respectively). With rising Wagner's grades, bacterial floras transformed from Gram-positive cocci to Gram-negative rods while fungus and composite infections increased. And 122 strains were of multi drug resistant organisms (MDRO). Among 357 strains of Gram-positive bacteria, Staphylococcus aureus, Staphylococcus epidermidis and Enterococcus faecalis were dominating floras. Staphylococcus was highly resistant to penicillin G, erythromycin, and oxacillin while vancomycin and linezolid were the most effective agents against gram-positive bacteria. Among 304 strains of gram-negative bacteria, enterobacteria were the most prevalent, including 48 strains of Escherichia coli, 34 strains of Proteus mirabilis and 31 strains of Proteus vulgaris. And there were 29 strains of Pseudomonas aeruginosa. Enterobacteria were highly resistant to ampicillin, followed by bactrim and furadantin while meropenem, imipenem, piperacillin/sulbactam, sulperazone and cefepime were the most effective agents. The predominant fungus was Blastomyces albicans.

Conclusions: In patients with severe diabetic foot ulcers, Gram-negative rods predominate while the prevalence of fungus and composite infections increases. Vancomycin and imipenem maintain highly antibacterial activity. It is essential to pay attention to pathogen survey and use antibiotics more rationally.