Pseudomonas aeruginosa: an uncommon cause of diabetic foot infection
Background:
Pseudomonas aeruginosa has traditionally been considered a common pathogen in diabetic foot infection (DFI), yet the 2012 Infectious Diseases Society of America guideline for DFI states that "empiric therapy directed at P aeruginosa is usually unnecessary." The objective of this study was to evaluate the frequency of P aeruginosa isolated from bone or tissue cultures from patients with DFI.
Methods:
This study is a cross-sectional survey of diabetic patients presenting with a foot infection to an urban county hospital between July 1, 2012, and December 31, 2013. All of the patients had at least one debridement procedure during which tissue or bone cultures from operative or bedside debridements were obtained. The χ(2) test and the t test of means were used to determine relationships between variables and the frequency of P aeruginosa in culture.
Results:
The median number of bacteria isolated from DFI was two. Streptococcus spp and Staphylococcus aureus were the most commonly isolated organisms; P aeruginosa was isolated in only five of 112 patients (4.5%). The presence of P aeruginosa was not associated with the patient's age, glycosylated hemoglobin level, tobacco abuse, the presence of osteomyelitis, a prescription for antibiotic drugs in the preceding 3 months, or the type of operative procedure.
Conclusions:
Pseudomonas aeruginosa was an infrequent isolate from DFI in this urban, underserved diabetic population. The presence of P aeruginosa was not associated with any measured risk factors. By introducing a clinical practice guideline, we hope to discourage frontline providers from using routine antipseudomonal antibiotic drugs for DFI.
Insights
Pseudomonas aeruginosa is rarely found in diabetic foot infections (DFI). This study found it in only 4.5% of cases, suggesting routine antibiotic treatment for this pathogen in DFI is unnecessary.
Area of Science:
- Infectious Diseases
- Microbiology
- Diabetology
Background:
- Pseudomonas aeruginosa is often assumed to be a common cause of diabetic foot infections (DFI).
- However, current guidelines suggest empiric therapy for P. aeruginosa in DFI is typically not required.
- This study aimed to determine the actual prevalence of P. aeruginosa in DFI.
Purpose of the Study:
- To evaluate the frequency of Pseudomonas aeruginosa (P. aeruginosa) isolation from bone or tissue cultures in patients with diabetic foot infections (DFI).
- To assess the association between P. aeruginosa presence and various patient and clinical factors.
Main Methods:
- A cross-sectional survey was conducted on diabetic patients with foot infections between July 2012 and December 2013.
- Tissue or bone cultures were obtained during debridement procedures.
- Statistical tests (chi-squared and t-tests) were used to analyze the frequency of P. aeruginosa and its relationship with other variables.
Main Results:
- The median number of bacterial isolates per DFI was two.
- Streptococcus spp. and Staphylococcus aureus were the most common bacteria found.
- P. aeruginosa was isolated in only 4.5% (5 out of 112) of patients and showed no association with age, HbA1c, smoking, osteomyelitis, recent antibiotic use, or procedure type.
Conclusions:
- Pseudomonas aeruginosa is an infrequent pathogen in diabetic foot infections within this urban, underserved population.
- No measured risk factors were associated with the presence of P. aeruginosa.
- Clinical practice guidelines should discourage routine use of antipseudomonal antibiotics for DFI based on these findings.
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