Clinicomicrobiological Profile of Podiatric Infections

A Prospective, Cross-Sectional Study

Swathi Holla V R, MSc; Sevitha Bhat, MBBS, MD; Archana Bhat K, MBBS, MD; and Shalini Shenoy Mulki, MBBS, MD

Disclosures

Wounds. 2023;35(7):E229-E235. 

In This Article

Abstract and Introduction

Abstract

Introduction: Podiatric infections are common in patients with and without diabetes. Biofilm detection would aid in determining the severity of foot infections and preventive strategies to manage them.

Objective: The authors studied the clinicomicrobiological profile of podiatric infections.

Materials and Methods: Organisms from podiatric specimens were identified and the antibiotic susceptibility of the organisms determined using standard microbiological methods. Organisms were screened for biofilm production using the microtiter plate method. Staphylococcus aureus isolates were screened for ica, cna, and hlg genes by multiplex PCR.

Results: A total of 117 patients were included in the study, and specimens from 71 patients were culture positive (60.6%). Gram-negative bacteria were predominant (n = 88 [73.3%]). S aureus (n = 32 [26.7%]) was the most common isolate. The rate of biofilm production was 54.2%. Pseudomonas aeruginosa was the most prevalent biofilm producer (82.8%). The study revealed a statistically significant association of biofilm formation with MDR, MRSA, and prior antibiotic therapy with multiple (≥4) antibiotics.

Conclusion: Isolation of MRSA or MDR strain from diabetic foot infections could alert the clinician to the possibility of treatment failure with a single drug regimen owing to associated biofilm production. Detection of biofilm producers and subsequent early debridement and/or cleaning of wounds might prevent chronic infection.

Introduction

Local infections of the foot, ankle, and lower extremity are known as podiatric infections. Podiatric infections are more frequent in countries where a considerable part of the population walks barefoot.[1] Individuals with diabetes have a lifetime risk of 25% in developing a DFU, thus diabetic foot problems remain a serious public health concern and DFUs continue to be a burden worldwide.[2] A previous study from India revealed that cellulitis was the most common foot infection among both those without diabetes (52%) and with diabetes (40%).[1] Peripheral vascular disease, peripheral neuropathy, and trauma are some of the risk factors for DFU. DFU accounts for the majority of lower extremity amputation globally.[3] Ulcer swab cultures are inferior to deep tissue and/or bone biospy because these specimens are more prone to contamination by superficial normal flora.[4] Bone biopsy is the most effective way to identify the true pathogen. However, deep tissue samples obtained by debridement of foot ulcers have taken the place of bone biopsy culture.[3,4]

There is a paucity of published data on the clinicomicrobiological profile of podiatric infections from parts of southwestern India. A previous study found Staphylococcus aureus to be the most prevalent gram-positive isolate (70.37%) and members of Enterobacterales (67%) and Pseudomonas aeruginosa (33%) to be the most prevalent gram-negative isolates.[4]

Biofilm production by bacteria is the cause of many persistent infections. Detection of biofilm assists in tailoring antibiotic therapy, optimizing treatment duration, and determining the necessity of surgical intervention, ultimately improving infection management and patient outcomes.[4,5] Therefore, the authors of the current study aimed to screen for biofilm production in these common isolates.

The ica A, C, B, and D genes have been associated with cell aggregation and biofilm development. In a study by Elboshra et al,[5] the ica gene was the most prevalent (73.9%), followed by cna (29.2 %) and hlg (7.6%). In this context, the authors of the current study aimed to screen for the common virulence gene carriage in S aureus for epidemiological purposes.

Medical professionals and clinical microbiologists in developing countries are equally concerned about the growing threat posed by MDR organisms. Hence, the authors of this study evaluated the microbiological profile, antibiogram, treatment, and clinical outcomes of podiatric infections to formulate a comprehensive treatment plan, especially in patients with diabetes.

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