The global burden of diabetes is steadily rising, with approximately 171 million individuals currently affected1. Projections suggest this number may climb to 366 million by the year 2030. According to the World Health Organization, India bears the largest share of this burden, with an estimated increase of 87 million diabetes cases expected by 20302. Diabetes Mellitus is a chronic metabolic disorder characterized by elevated blood glucose (sugar) levels due to either insufficient insulin production by the pancreas, ineffective use of insulin by the body's cells, or a combination of both. This condition leads to prolonged hyperglycemia, which, if left unmanaged, can result in serious complications affecting the eyes, kidneys, nerves, heart, and blood vessels3. The prevalence of diabetes-associated complications, including foot infections, have been increasing in India and other countries.4-6 Multidrug-resistant organisms (MDROs) are bacteria that are resistant to current antibiotic therapy and, therefore, difficult to treat. MDROs can cause serious local and systemic infections that can be severely debilitating and even life threatening. Diabetic wounds tend to be polymicrobial and are often colonized by multidrug-resistant (MDR) organisms such as Staphylococcus aureus (including MRSA), Pseudomonas aeruginosa, Klebsiella spp., and Escherichia coli7,8. In contrast, nondiabetic wounds, though not immune to infection, generally display a less complex microbial profile and lower resistance burden9. Antimicrobial resistance (AMR) has become a global public health crisis, with higher prevalence observed in low- and middle-income countries due to inappropriate antibiotic prescribing, poor infection control practices, and over-the-counter antibiotic availability10. India is particularly affected, ranking among the top countries in antibiotic consumption and resistance emergence11. Studies have shown that inappropriate empirical antibiotic use in wound infections contributes significantly to the emergence of multidrug-resistant (MDR) organisms, making treatment outcomes unpredictable and resource-intensive12-13 The comparative microbiological and resistance profiles of diabetic and nondiabetic wound infections remain underexplored, especially in tertiary care hospitals in India. There is a pressing need for localized data to guide evidence-based empirical therapy and antimicrobial stewardship. This study aims to compare the prevalence and antibiotic resistance patterns of microbial isolates from infected wounds in diabetic versus nondiabetic patients. The findings are expected to enhance clinical decision-making, contribute to the rational use of antibiotics, and inform infection prevention policies within tertiary care settings.

Data collection and study guidelines This observational study included 80 patients, 40 in each group, involving patients previously diagnosed with diabetic or non-diabetic patients with infected wound who are attending surgery outpatient or admitted in surgery wards, SICU and also burn unit in K R Hospital, Mysore Medical College and Research Institute. Specimens will be collected as pus samples or wound swabs and processed and sent for the culture and sensitivity. Their antibiotic susceptibilities were recorded. A pre-designed and pre-tested structured proforma was used to collect the necessary information. The following data were collected and assessed: demographic details of the patients, diabetic status, diagnosis of patient, baseline examination findings wound culture and sensitivity, antibiotic sensitivity testing, and the total number of antibiotics to which the organism demonstrated resistance was recorded to identify multi-drug resistance among the isolated bacteria. Patient Inclusion and Exclusion Criteria in the Study All patients aged between 18-89 diabetic and non-diabetic patients with infected wound (such as infected diabetic foot ulcers, infected varicose ulcers, infected burn wounds, infected traumatic wounds, surgical site infections, infected bite wounds etc.). And yielding a positive urine culture were included. For the selection of diabetic patients, we considered a random blood sugar level greater than 200 mg/dl or diagnosed with diabetes mellitus with a treatment duration of more than one year Positive wound culture. Patients below 18 years and above 89 years and patients with history of chronic renal or hepatic failure, terminally ill patients, patients who refused to give consent, and pregnant women were excluded. Statistical Analysis: Data collected will be analysed using descriptive statistical methods: mean, standard deviation, frequency and percentage. Interferential test like Chi-square test will be used for intragroup comparison and p values < =0.05 will be considered to be of statistical significance. All the above statistical analysis will be performed using SPSS software for windows version 28.

Distribution of the Study Population A total of 80 patients, evenly distributed into non-diabetic and diabetic groups, included 29 (72.5%) males and 11 (27.5%) females in the non-diabetic group, and 26 (65%) males and 14 (35%) females in the diabetic group. The mean age of patients was 50 years (ranging from 18 to 80 years) in the non-diabetic group and 62 years (ranging from 38 to 80 years) in the diabetic group. Details are provided in Table 1. Table 1: Age and Gender-wise Distribution of Patients in the Studied Population GROUP MEAN AGE GENDER MALE FEMALE DIABETIC (N=40) 62 Years 26 (65%) 14 (35%) NON-DIABETIC (N=40) 50 Years 29 (72.5%) 11 (27.5%) Where N= Number of patients included in the group Comparison of diagnosis:- In the present study, various diagnoses were compared between diabetic and non-diabetic patients. Cellulitis was the most common diagnosis in both groups, accounting for 14 cases among diabetics and 12 among non-diabetics. Diabetic foot was seen exclusively in diabetic patients (10 cases), while burns were reported only in non-diabetics (4 cases). Foot ulcers were more frequent in non-diabetics (10 cases) compared to diabetics (1 case). Other conditions like abscesses, carbuncles, gangrene, osteomyelitis, and surgical site infections were observed in both groups to varying extents. A statistically significant difference was observed in the pattern of diagnoses between the two groups Table 2: Comparison of diagnosis Diagnosis Groups Total Diabetic Non diabetic Abscess 4 2 6 Burns 0 4 4 Carbuncle 3 0 3 Cellulitis 14 12 26 Diabetic foot 10 0 10 Fournier’s gangrene 1 3 4 Foot ulcer 1 10 11 Gangrene 3 1 4 Osteomyelitis 1 0 1 Surgical site infection 3 8 11 Total 40 40 80 Distribution of Microorganisms As shown in Figure 1A and 1B, microorganisms primarily belonged to seven different species. Gram-negative bacteria constituted approximately 16 (96.66%) and 21 (90%) of total isolates in the diabetic and non-diabetic groups, respectively, with the remaining being gram-positive. The most prevalent organism among all patients was Staphylococcus Aureas, accounting for (19)43.33% in non-diabetic and (13)50% in diabetic patients. E.Coli, Klebsiella, Pseudomonas, Streptococci, Proteusand Citrobater were common in both groups, with varying percentages. Results of Antibiotic Sensitivity and Resistance Patterns of Common Microorganisms among Diabetic and Non-Diabetic Table 2 summarizes microbial sensitivity and resistance patterns in diabetic and non-diabetic patients. Ciprofloxacin resistance was high in both groups (85% in diabetics vs. 60% in non-diabetics), though the difference was not statistically significant (p=0.819). Ceftazidime resistance was seen in 67.5% of diabetic and 47.5% of non-diabetic patients, with sensitivity higher in non-diabetics (27.5%) than diabetics (15%). Ampicillin, Cefotaxime, and Cefoperazone also showed moderate levels of resistance across both groups, with no significant difference in sensitivity. Imipenem and Meropenem demonstrated high sensitivity rates in both diabetic (52.5% and 45%, respectively) and non-diabetic patients (70% and 50%, respectively), indicating strong efficacy. Linezolid showed excellent sensitivity in both groups (55% in diabetics, 45% in non-diabetics) and low resistance rates. Cotrimoxazole showed borderline statistical significance (p=0.054), with greater resistance among diabetics (30%) than non-diabetics (12.5%). Drugs like Gentamicin, Amikacin, and Colistin exhibited variable resistance, but were generally more effective in non-diabetic patients. Piperacillin–tazobactam was effective in both groups, showing high sensitivity (22.5% in diabetics, 37.5% in non-diabetics). Overall, while resistance patterns varied between diabetic and non-diabetic patients, most differences were not statistically significant. The findings highlight the importance of personalized antibiotic selection based on comorbid conditions such as diabetes Multi drug resistance Multidrug resistance (MDR), defined as resistance to ≥ three antimicrobial agents [34], was observed in 100% of diabetic patients. Among non-diabetics, 81.66% (49/60) exhibited MDR. Three (2.5%) of the isolates were resistant to one antibiotic, and eight of them demonstrated resistance to two antibiotics. S.no Name of the drug Drug resistance Drug sensitivity P-value Diabetic Non-diabetic Diabetic Non-diabetic 1 Ciprofloxacin 34(85%) 24(60%) - 6(15%) 0.819 2 Ceftazidime 27(67.5%) 19(47.5%) 6(15%) 11(27.5%) 0.172 3 Ampicillin 10(25%) 8(20%) 3(7.5%) 6(15%) 0.42 4 Cefotaxime 15(37.5%) 19(47.5%) 6(15%) 8(20%) 1.0 5 Cefoperazone 16(40%) 10(25%) 7(17.5%) 9(22.5%) 0.42 6 Ofloxacin 22(15%) 32(80%) - 3(7.5%) 0.276 7 Cotrimoxazole 12(30%) 5(12.5%) 7(12.5%) 12(30%) 0.054 8 Imipenem 4(10%) 3(7.5%) 21(52.5%) 28(70%) 0.688 9 Amoxy Clavulinic Acid 26(65%) 10(25%) 4(10%) 5(12.5%) 0.135 10 Meropenem 5(12.5%) 2(5%) 18(45%) 20(50%) 0.414 11 Liezolid 12(30%) 9(22.5%) 22(55%) 18(45%) 1.0 12 Gentamicin 20(50%) 13(3.2%) 10(25%) 15(37.5%) 0.197 13 Amikacin 6(15%) 12(30%) 1(10%) 6(15%) 0.626 14 Colistin 1(2.5%) - 19(47.5%) 25(62.5%) 0.381 15 Piperacillin-azobactam 3(7.5%) 1(2.5%) 9(22.5%) 15(37.5%) 0.285

The primary objective of this study was to compare the resistance pattern to multiple antibiotics used in wound infection among diabetic and non-diabetic patients to determine if diabetes plays any role in the drug resistance pattern. Our study also aims to identify the most common organism causing wound infection, which was found to be staphylococcus aureus in both the groups. The present study reveals a predominance of Gram-negative organisms in wound infections of both diabetic (96.66%) and non-diabetic (90%) patients, aligning with Shanmugam et al., and also Staphylococcus aureus emerged as the most common isolate in both groups, with higher prevalence in diabetics (50% vs. 43.33%), consistent with findings by Gadepalli et al., who highlighted its frequent methicillin resistance and associated treatment challenges14. In contrast, non-diabetic wounds showed a slightly broader spectrum of pathogens, suggesting that factors like hygiene practices, trauma, and hospitalization duration could influence colonization patterns. Studies like those by Tentolouris et al. and Lipsky et al. emphasize the role of host immunity and wound care protocols in shaping microbial profiles15-16. The antimicrobial resistance patterns observed in our study reflect significant therapeutic challenges in managing wound infections, especially in diabetic individuals. Ciprofloxacin resistance was notably high in both diabetic (85%) and non-diabetic (60%) patients. Although not statistically significant, this trend is in line with reports by Ramakant et al., who found widespread fluoroquinolone resistance among Gram-negative isolates in diabetic foot infections, likely due to overuse and empirical prescribing practices15. Ceftazidime resistance was also higher in diabetics (67.5%) compared to non-diabetics (47.5%). A similar pattern was documented by Zubair et al., who reported reduced cephalosporin efficacy in diabetic wounds, particularly among E. coli and Klebsiella isolates8. This may be attributed to extended-spectrum β-lactamase (ESBL) production, commonly seen in diabetic patients with recurrent or chronic infections. Carbapenems, specifically Imipenem and Meropenem, demonstrated relatively high sensitivity in both groups, with non-diabetics showing slightly better outcomes (70% vs. 52.5% for Imipenem). This supports the findings by Lipsky et al., who noted the retained efficacy of carbapenems in complicated skin and soft tissue infections, particularly in multidrug-resistant organisms 17. Linezolid showed excellent sensitivity in both groups (55% diabetics, 45% non-diabetics), making it a reliable option for Gram-positive infections, especially methicillin-resistant Staphylococcus aureus (MRSA). This is consistent with the study by Tentolouris et al., where Linezolid was highlighted as a key agent in managing resistant Gram-positive cocci in diabetic foot ulcers18. The study found a high prevalence of multidrug resistance (MDR), with all diabetic patients (100%) and 81.66% of non-diabetic patients showing resistance to ≥3 antibiotic classes. This aligns with studies by Zubair et al. and Shanmugam et al., which link MDR in diabetics to prolonged infections, repeated antibiotic use, and poor glycemic control8. Non-diabetics showed relatively lower MDR, consistent with Banu et al.19. The presence of biofilm-forming organisms like Pseudomonas and Klebsiella, as noted by Ramakant et al. and James et al., may further contribute to resistance in chronic diabetic wounds 15,20. These findings emphasize the need for targeted antibiotic therapy, routine sensitivity testing, and strict stewardship.

Patients with diabetes suffering from wound infections exhibited a notably higher occurrence of multidrug-resistant (MDR) bacterial strains compared to non-diabetic individuals. While Staphylococcus aureus remained the most frequently detected pathogen across both groups, Gram-negative bacteria were found more commonly in diabetic patients. Despite the overall resistance patterns, antibiotics such as Imipenem, Meropenem, Amikacin, and Linezolid continued to show strong effectiveness against the isolated organisms. These results highlight the importance of performing regular culture and sensitivity testing for infected wounds, especially in diabetic individuals, to ensure targeted and effective antibiotic therapy. Rational use of antimicrobials, along with proactive measures including optimal blood sugar control, proper wound care, and timely medical or surgical intervention, are critical to managing infections and reducing antimicrobial resistance in this high-risk group

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