Introduction
Diabetes Mellitus is a chronic disorder affecting a large population & acts as a major public health problem in India.1 Infected foot ulcer is a common cause of morbidity in diabetic patients, leading to dreaded complications like gangrene & amputations.2 Three main factors responsible for this are neuropathy, angiopathy & immunopathy. Neuropathy is the most important factor: minor irritations & trauma can lead to life threatening infections without the patient feeling the changes. 3
Most diabetic foot diseases are valid crises: Anti-toxin treatment ought to be begun quickly to work on the possibilities rescuing the appendage.4 Contaminations are frequently polymicrobial, Multi drug safe & related with deficient glycemic control. Subsequently, there is a requirement for consistent observation of safe microscopic organisms to give the premise to exact treatment & lessen the gamble of intricacies. 5
Many examinations have given an account of the bacteriology of Diabetic Foot Contaminations throughout recent years, however the outcomes have been shifted & frequently incongruous. These errors could be because of the distinctions in the causative life forms which has happened over the long haul, topographical varieties or the sort & the seriousness of the contamination, as announced in the examinations.6 The current review was embraced to decide the bacteriological profile of Diabetic foot ulcer in our space.
Materials and Methods
This is a cross-sectional, observational study conducted over a period of 6 months (November 2021 to April 2022) in the Department of Microbiology. The study includes 110 samples from patients with Diabetic foot ulcer attending the outpatient department of Surgery. The ulcer grading was done according to Wagner Meggitt classification. Patients with ulcer grade one or more were included in the study & patients with grade zero or limb amputations were excluded from the study.
Specimen like pus, exudates or tissue biopsy were obtained from the ulcer. Pus & exudates were collected from the margin & the base of the ulcer using two sterile swabs & transported in a sterile test tube. Tissue biopsy was taken using a sterile blade in wedge shape including the base & margin of the ulcer & transported in sterile normal saline. The specimens were sent immediately to the microbiology laboratory for further processing.
One swab was used for Gram’s staining & the second swab was used to inoculate on Blood agar & MacConkey agar for the isolation of aerobic bacteria. The Gram stained smear was examined under microscope for the presence of pus cells & bacteria. The inoculated plates were incubated overnight at 37ᵒC. The bacterial growth obtained was identified based on morphology, cultural characteristics & biochemical reactions according to standard protocol.7 The antibiotic susceptibility testing of the isolated bacteria was done by Kirby Bauer’s Disc Diffusion method on Mueller Hinton agar using the antibiotics & interpretation was done based on CLSI (Clinical Laboratory Standard Institute) Guidelines. Due to lack of facilities, anaerobic culture was not done. Results were analyzed for aerobic bacteria only.
Results
Among 110 clinically diagnosed cases of diabetic foot ulcer that were included in the study 73 (66.4%) showed monomicrobial growth, 29 (26.4%) showed polymicrobial growth & 8 (7.2%) cases were sterile on culture (Table 1).
Table 1
Number of bacteria isolated from Diabetic foot ulcer
|
Monomicrobial growth |
73 |
66.4% |
|
Polymicrobial growth |
29 |
26.4% |
|
No Growth |
08 |
7.2% |
|
Total |
110 |
100% |
In our study, 134 aerobic bacteria were isolated from 110 diabetic patients. 102 (76.1%) were Gram negative bacilli & 32 (23.9%) were Gram positive cocci. Further distribution of pathogens is depicted in Table 2. Among Gram negative bacilli, E. coli (18.6%) was the most common isolate followed by Klebsiella spp (17.1%), Citrobacter spp (11.2%), Pseudomonas spp (7.5%), Proteus spp (7.5%), Enterobacter spp (7.5%), Non-fermenting Gram negative bacilli (5.2%) & Acinetobacter spp (1.5%). Among Gram positive cocci, Staphylococci aureus (11.9%) was frequently isolated followed by Coagulase negative Staphylococci (4.5%) & Enterococci spp (7.5%) respectively.
Table 2
Various Bacteria identified from diabetic foot ulcer
In the present study, most of the Gram-negative bacilli were sensitive to Amikacin (61.8%) followed by Gentamicin (56.9%), Meropenem (50.9%), Imepenem (49.0%), Piperacillin-tazobactum (43.1%), Ciprofloxacin (30.4%), Cefipime (23.5%), Amoxyclav (16.6%), Ceftrixone (12.7%) & less sensitivity to Cephotaxime (10.8%) shown in Table 3.
Table 3
Antibiotic susceptibilitypattern of Gram negative bacilli
Table 4
Antibiotic susceptibility pattern of Staphylococci
Table 5
Antibiotic susceptibility pattern of Enterococci
|
Antibiotic |
Number (n=10) |
Percentage (%) |
|
Vancomycin |
10 |
100% |
|
Linezolid |
10 |
100% |
|
Amoxyclav |
08 |
80% |
|
Tetracycline |
06 |
60% |
|
Ciprofloxacin |
06 |
60% |
|
High Level Gentamicin |
05 |
50% |
|
Penicillin |
04 |
40% |
|
Cefotaxime |
03 |
30% |
Table 6
Antibiotic susceptibility pattern of isolated Gram negative bacilli
Table 7
Antibiotic susceptibility pattern of isolated Gram positive cocci
The sensitivity pattern of Staphylococci is shown in Table 4. All the Staphylococcal isolates showed 100% sensitivity to Vancomycin & Linezolid followed by Clindamycin (77.2%), Gentamicin (63.6%), Ciprofloxacin (63.6%), Tetracycline (63.6%), Erythromycin (40.9%), Amoxyclav (31.8%), Cephotaxime (18.2%). None of the isolates were sensitive to Penicillin.
All the Enterococci isolates showed sensitivity to Vancomycin & Linezolid. The sensitivity to Amoxyclav was 80% followed by Tetracycline (60%), Ciprofloxacin (60%), High Level Gentamicin (50%), Penicillin (40%) & Cephotaxime (30%) shown in Table 5.
Sensitivity pattern of isolated Gram negative bacilli & Gram positive cocci is presented in Table 6, Table 7 respectively. Amikacin was the most susceptible antibiotic to all bacterial isolates & Cephalosporins were the most resistant antibiotics. Non-fermenters (Pseudomonas spp, Acinetobacter spp & others) showed decreased sensitivity to carbapenems compared to Enterobacteriaceae (E. coli, Klebsiella spp, Citrobacter spp, Proteus spp, Enterobacter spp). Both the Acinetobacter isolates showed resistance to all antibiotics that were tested. In our study 13.7% of Gram negative bacilli were Extended Spectrum Beta Lactamase (ESBL) producers & 31.2% of Staphylococci were MRSA.
Discussion
Diabetic foot ulcer is a significant entanglement of Diabetes mellitus. Untreated diabetic foot ulcers will become tainted prompting different outcomes like gangrene or removal of the appendage.8 The diabetic foot contaminations are for the most part blended bacterial diseases. In our review, 26.4% of cases showed polymicrobial development which is as per numerous different examinations. 9, 10, 11
In the current review, bacterial profile of diabetic foot ulcer showed lion's share of Gram negative microorganisms (76.1%) more than Gram positive microbes (23.9%) & overwhelming confines were individuals from Enterobacteriaceae which is likewise seen in different examinations. 12, 13 It is consistently important to assess various microorganisms contaminating the injury on a normal premise notwithstanding standard glycemic control, wound care, careful debridement, pressure-offloading & keeping up with satisfactory blood supply.14 to execute focused on & right antimicrobial treatment, having information & consciousness of the normal culpable microbes in diabetic foot infections is fundamental. 15
In the current review, the most often detached microorganisms is E. coli (18.6%) trailed by Klebsiella spp (17.1%), S. aureus (11.9%) & Citrobacter spp (11.2%) which is like review done by Ako-Nai et al.16 conversely, different examinations show S. aureus & Pseudomonas spp as dominating microorganisms. 17, 18, 19, 20
Our review shows that the detached microorganisms had different responsiveness designs against normally utilized anti-microbials. A large portion of Gram-negative bacilli were impervious to routine anti-toxins like cephalosporins & Non fermenters showed diminished aversion to carbapenems. Greater part of gram-positive cocci showed protection from Penicillin, Cefotaxime & Erythromycin which corresponds with the aftereffects of different investigations.
Diabetic foot ulcers are exceptionally inclined to colonization with antimicrobial-safe life forms, including methicillin-safe Staphylococcus aureus & expanded range beta-lactamase delivering gram negative creatures.21 In our review 13.7% of Gram-negative bacilli were ESBL makers & 31.2% of Staphylococci were MRSA. In a concentrate by Saraswathy KM et al, 68.8% of the Gram-negative bacilli were ESBL makers & 21% of Staphylococci were impervious to Methicillin.
Factors liable for MDR might be regular hospitalization, utilization of wide range anti-infection agents, lacking careful source decrease, persistent injuries, silly utilization of anti-microbials, & the exchange of obstruction qualities. To lighten what is happening & furthermore to decrease the pace of removal, clinicians ought to recommend anti-infection agents normally, convenient & adequately & there ought to be occasional oversights on the medication utilization by the individual association. Clinicians ought to change to culture report based utilization of smaller range treatment. A satisfactory & ideal careful mediation is fundamental to accomplish contamination source decrease.22 In this way, early identification of causative microbes & determination of suitable anti-toxins in view of the antimicrobial testing is need of great importance for the legitimate administration of diabetic foot ulcer.
Conclusion
Diabetic foot ulcer infections are one of the major problems in diabetic patients & requires a team approach for its effective management. E. coli, Klebsiella spp, S. aureus & Pseudomonas spp were found to be the prevalent bacteria & unfortunately these bacteria have shown increased resistance to most effective antibiotics. Hence, there is need for periodic bacteriological evaluation which improves treatment outcome, reduces complications as well as emergence of multidrug resistance.
