Clinical Research on Foot & Ankle
Open Access

Staphylococcus Aureus; Antibiotic

Introduction

Diabetes patients frequently develop foot ulcers; the prevalence rate can reach 25%. The spread of infection to soft tissue and skeletal structures is a primary contributing cause of lower-limb amputation from these lesions, which frequently become infected. The most frequently isolated pathogen in diabetic foot infections is Staphylococcus aureus (DFIs) [1]. Staphylococcal infections develop and spread as a result of a number of virulence factors acting in concert with the host's immunological state. Due to the enormous heterogeneity in the structure and mode of action of bacterial factors, certain metabolic and adhesion qualities are conferred upon the bacteria, as well as defence against the vast majority of innate immune effectors. Although their role in staphylococcal infection is still unclear, S. aureus's epidermal differentiation factor (EDIN) and EDIN-like factors are among those with a known method of action. The tiny host protein RhoA is the target of a class of bacterial exotoxins, including EDIN. The host cell actin cytoskeleton is significantly regulated by this small GTPase. Numerous research on cell biology have shown that RhoA inhibition has a negative effect on the cohesiveness of epithelial and endothelial barriers, which is likely to favour bacterial spread. EDIN factors appear to play a part in bacterial colonisation and host tissue invasion, according to a vast number of research looking at the effects of RhoA inhibition. Two clonal complexes and a variety of virulence factors, according to a prior multicenter investigation on clinical isolates of S. aureus, can be utilised to distinguish between healthy and unhealthy diabetic foot ulcers. In fact, we found a connection between the colonising S. aureus strains with a successful outcome and the clonal complexes CC5/CC8 [2-5]. We also identified a collection of virulence variables, including sea, sei, lukDE, and cap8, that are linked to worse DFU outcomes. Two highly frequent factors, lukDE and hlgv, were shown to be acceptable genetic markers to predict risk of infection by S. aureus by a more in-depth investigation of virulence factors linked to infecting strains utilising DNA array technology (p 0.005).

Method utilize

After obtaining informed consent, we prospectively enrolled a sample of outpatients seeking treatment for any type of DFU between 1 April 2008 and 30 June 2010 at one of 12 participating French foot clinics. The local ethics committee gave its blessing to this study, which was conducted in conformity with the 2000 revision of the Declaration of Helsinki. If a patient hadn't had any antibiotics in the previous week, they were included in the study. A qualified physician checked each patient to determine the severity of the infection. Wounds were classified as either infected or uninfected based on the IDSA-IWGDF criteria [6]. Following wound debridement, tissue biopsy, needle aspiration, or swabbing the wound base were used to collect samples for bacterial culture, which were then sent right away to the bacteriology department.

Scientific analysis

At the INSERM laboratory in Nîmes, France, every strain of S. aureus that was gathered for the study was examined. The Alere StaphyType DNA microarray was used in accordance with the previously described techniques and procedures. In 5 hours, the test was able to simultaneously screen several markers. Two edin-isofoms, edinA and edinB, are among the 334 target sequences covered by the DNA microarray. Sequences for primers and probes have already been published. Each S. aureus strain's DNA was extracted, and markers were found following amplification and hybridization. By using this approach, strains' clonal complexes (CC) are identified. A group of strains (clones) that are sufficiently similar to one another to be said to have a common ancestor may be the best way to define a CC [7].

Medical and microbiological information

195 patients were enrolled throughout the research period. At the outset, 75 wounds (38.5%) were deemed to be clean, whereas 120 were deemed to be infected. 18 patients (24%) returned to the outpatient department during the follow-up period as a result of a wound that was rapidly getting worse: four acquired a grade 2 ulcer, 12 a grade 3 ulcer, and two a grade 4 ulcer. At the follow-up visit, 33 patients (44%) had their wound not fully re-epithelialized: a sample for bacterial culture was obtained, and the outcome was considered as favourable. In 24 patients (32%), the wound was considered healed [8]. At baseline, S. aureus isolate was found to be positive for edin (A and B) genes in 14 patients (7.2%): six isolates were recovered from the patients with clinically uninfected DFUs (8%). 24 of the initially uninfected wounds totally healed throughout the follow-up period, while 33 wounds improved but weren't closed, and 18 wounds got worse. At first, no strain of S. aureus from the healed lesions tested positive for edin genes. Four of the six uninfected DFUs containing edin-positive S. aureus had a favourable result (66.7%), but two (33.3%) rapidly deteriorated (within 30 days) with the appearance of a grade 4 DFI. Notably, whether the outcome was favourable or not, a S. aureus strain was recovered from the second bacterial sampling done in those uninfected ulcers that were not fully healed at the follow-up visit. We discovered here that S. aureus edin-positive strains were more frequently found in severe grade 3/4 ulcers. 7.2% (14/195) of the isolates were edin-positive. Only one (0.5%) of the 14 edin-positive S. aureus strains tested positive for edin-A, while 13 (6.7%) tested positive for edin-B, according to DNA array analysis. A colonising sample included the S. aureus strain that was edin-A positive [9]. Five patients and eight patients with grade 3/4 infected ulcers had colonisation samples with edin-B-positive bacteria recovered from them. Only the two rapidly and seriously deteriorating DFUs were found to have edin-B-positive S. aureus in the second bacterial sampling that was done on the uninfected wounds that had not fully healed. In the four DFUs with favourable outcome, the strains isolated at follow-up no longer harboured any edin-isoforms; moreover, these strains were not the same as initially assessed by difference [10].

Discussion

DFUs are vulnerable to infections that could progress rapidly, necessitate the amputation of lower extremities, and even result in death. Due to the neuropathy and/or ischemia's masking effects, it may be difficult to tell colonisation from infection in DFUs from a clinical standpoint. In order to examine the distribution of bacterial variables across infecting and colonising strains of S. aureus, monomicrobial DFI constitutes a novel paradigm in people. Although a number of factors work together to give S. aureus its virulence potential, those linked to strains that colonise grade 1 DFUs are likely to play a minor influence in virulence and particularly in invasion. A singleton close to CC8 (edin-A, n = 1), a singleton associated with ST152-MSSA (edin-B, n = 1), a singleton associated with CC80-MRSA (edin-B, n = 2), and a singleton associated with CC25/28-MSSA (edin-B, n = 10) are the four primary groups that the clonal complex analysis shows the edin- Here, we discovered a ST152-MSSA strain that is edin-B positive and et D negative. Importantly, this strain appeared negative for the haemolysin (hlgv) and the leukocidin (lukDE) genes, which have been defined as two highly prevalent virulence markers of infectious strains in DFU. Given that the edinB-positive ST152 strain of S. aureus was isolated from a Grade 4 ulcer, this result further emphasizes the interest in screening edin-B as a surrogate maker to discriminate colonizing from infecting strains of S. aureus in DFU.

Conclusion

The discovery of some CCs and virulent genes in grade 1 ulcers challenges the conventional wisdom that clinically uninfected ulcers should not receive antibiotic therapy and calls into question the use of antibiotics in apparently uninfected DFU. In fact, the lack of CC5/CC8 in the colonising bacteria and the presence of CC25/28 and/or the genes for lukDE, hlgv, and edin suggest that antibiotic therapy is necessary as a therapeutic approach. But until to now, most of the methods we employed were in the realm of study.

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