Clinical and Bacteriological Analyses of Biofilm-Forming Staphylococci Isolated from Diabetic Foot Ulcers

Abstract

Background Diabetes mellitus is a chronic disease that is associated with increased morbidity and mortality. Unfortunately, foot ulcers and amputations due to diabetes are very common in developing countries. The purpose of this study was to characterize the clinical presentation of diabetic foot ulcer (DFU) infections, isolate the causative agent, and analyze the biofilm formation and distribution of biofilm-related genes among isolated Staphylococci. Material and Methods The study included 100 diabetic patients suffering from DFUs attending Assiut University Hospital. Swabs were collected and antimicrobial susceptibility testing of the isolates was performed. Biofilm formation was tested phenotypically among staphylococcal isolates and the frequency of different biofilm genes was analyzed by PCR. Clinical presentations of diabetic foot ulcers were correlated with bacterial genetic characteristics. Spa types were determined using DNA Gear-a software. Results Microbiological analysis showed that 94/100 of the DFUs were positive for bacterial growth. The majority of infections were polymicrobial (54%, n=54/100). Staphylococci were the most commonly detected organisms, of which S. aureus represented 37.5% (n=24/64), S. haemolyticus 23.4% (n=15/64), S. epidermidis 34.3% (n=22/64) and other CNS 4.7% (n=3/64). Interestingly, co-infection with more than one species of Staphylococci was observed in 17.1% (n=11/64) of samples. A high level of antibiotic resistance was observed, where 78.1% (n=50/64) of Staphylococci spp were multidrug-resistant (MDR). Phenotypic detection showed that all isolated Staphylococci were biofilm-formers with different grades. Analysis of biofilm-forming genes among Staphylococci showed that the most predominant genes were icaD, spa , and bap . Isolates with a higher number of biofilm-related genes were associated with strong biofilm formation. Sequencing of the spa gene in S. aureus showed that our isolates represent a collection of 17 different spa types. Conclusion The majority of DFUs in our hospital are polymicrobial. Staphylococci other than S.aureus are major contributors to infected DFUs. MDR and biofilm formation are marked among isolates, which is paralleled by the presence of different categories of virulence-related genes. All severely infected wounds were associated with either strong or intermediate biofilm formers. The severity of DFU is directly related to the number of biofilm genes.

Combining antibiotic‐loaded bone cement‐based free vastus lateralis muscle‐sparing flap with split‐thickness skin grafts: A reliable strategy for reconstructing diabetic foot ulcers at non‐weight‐bearing areas

“…Most DFU infections are polymicrobial, with Staphylococcus aureus , Pseudomonas aeruginosa and Escherichia coli being the primary pathogens. 21 , 22 In recent years, ALBC has been used to treat DFUs 23 , 24 , 25 , 26 as it is mixed with antibiotics such as gentamicin, tobramycin and vancomycin. 27 This mixture can continuously release antibiotics locally, slowly and effectively killing the bacteria commonly infecting DFUs, thus avoiding the systemic side effects of medications.…”

Down-regulation of β-lactam antibiotics resistance and biofilm formation by Staphylococcus epidermidis is associated with isookanin

“…During the initial attachment phase, the autolysin E (AltE) can mediate bacterial adhesion to hydrophobic surfaces, and secretion of autolysin is disturbed by the Esp protease of S. epidermidis ( Chen et al., 2013 ; Marek et al., 2021 ). After entering the aggregation phase, the accumulation-associated protein (Aap) can form fibrous structures on the cell surface and promote cell-to-cell interactions, and PIA-independent biofilms were mediated through Aap ( Mamdoh et al., 2023 ). Exopolysaccharides, cell surface proteins, and extracellular DNA are the main components of Staphylococcal biofilm formation, and biofilm exopolysaccharides are mainly polysaccharide intercellular adhesin (PIA) ( Mirzaei et al., 2019 ).…”

“…Exopolysaccharides, cell surface proteins, and extracellular DNA are the main components of Staphylococcal biofilm formation, and biofilm exopolysaccharides are mainly polysaccharide intercellular adhesin (PIA) ( Mirzaei et al., 2019 ). The ica locus can control the production of PIA from UDP-N-acetylglucosamine ( Mamdoh et al., 2023 ). Moreover, Staphylococcal accessory regulator A (SarA), biofilm-associated protein (Bap), RNA III, and QS system etc also can regulating the biofilm formation ( Mamdoh et al., 2023 ).…”

“…The ica locus can control the production of PIA from UDP-N-acetylglucosamine ( Mamdoh et al., 2023 ). Moreover, Staphylococcal accessory regulator A (SarA), biofilm-associated protein (Bap), RNA III, and QS system etc also can regulating the biofilm formation ( Mamdoh et al., 2023 ). Because of the very complex mechanism of biofilm formation, it hinders the treatment of bacterial diseases.…”

Antibacterial Activity Test of Gotu Kola Leaf Extract (Centella asiatica) Against Staphylococcus aureus Bacteria Isolated from Wounds of Diabetes Mellitus Patients

“…The most common microorganisms in the researcher's investigation were Staphylococcus sp. Staphylococcus aureus was the most common bacteria in ulcers (97%), Staphylococcus aureus is the most frequent pathogenic bacteria in diabetic feet, and 50% of isolated cases are methicillin-resistant (MRSA) (Anafo et al, 2021;Chiţǎ et al, 2013;Mamdoh et al, 2023;Taki et al, 2023). High antibiotic use generates difficulties and threatens world health, including bacterial resistance (Stachelek et al, 2021;Varela et al, 2021).…”