Determination of bacterial isolate profiles, their antimicrobial susceptibility patterns and trends of antibiotic use in patients with open fractures.

Abstract

Background: Open fractures are a high burden both locally and globally. Their commonest complication is wound infection, which often escalates to sepsis, osteomyelitis, amputation and even death. The morbidity and mortality from these infections is particularly high in developing countries. The use of prophylactic antibiotics is one of the most effective strategies to prevent infection. The selection of antibiotics for both prophylactic and empiric therapy must be guided by the institution’s microbial profile and susceptibility patterns of possible infecting organisms. Study objective: To determine the microbial profile and susceptibility patterns of bacterial isolates from infected open fractures. Design: Descriptive Cross-Sectional Study. Setting: Orthopedic wards at Kenyatta National Hospital. Patient and methods: Patients presenting to the hospital with open appendicular skeleton fractures whose wounds developed infection were recruited into the study. Their baseline characteristics as well as details relating to the fracture patterns were recorded. The wounds were assessed for infection after the 3rd and 8th day following initial debridement. Swab specimens were collected for Microscopy Culture and Sensitivity. The profile of cultured isolates were recorded as well as their antimicrobial susceptibility patterns. The prescribed antibiotics and their duration was also recorded. Data was analyzed in IBM SPSS version 22. Means, median and proportions were used to analyze the descriptive. Results: There were 45 (73%) gram negative and 17 (27%) gram positive bacterial isolates. The most pre-dominant bacterial isolate was Pseudomonas aeruginosa at 21 (34%). There were 17 (27%) Staph. aureus isolates, 12 (20%) E.Coli, 10 (16%) Proteus mirabilis and 2(3%) Klebsiella pneumoniae isolates. Among the Gram positive isolates, there was high resistance against Benzyl penicillin (100%), Amoxicillin Clavulanate (82%), Erythromycin (80%), Cefuroxime (75%), Ceftriaxone 60% and Clindamycin (50%). There were 4 Methicillin Resistant staph. aureus isolates. There was 100% sensitivity to Meropenem, Amikacin, Vancomycin, Piperacillin and Linezolid. Among the Gram Negative isolates, there was high resistance to Clindamyci (100%), Erythromycin (100%), Amoxicillin Clavulanate (94%), Ampicillin (80%), Cefuroxime (68%), Rifampicin (65%) and Ceftriaxone (54%). There was 100% sensitivity to Meropenem, Amikacin and Piperacillin. More than 80% of the isolates showed resistance to more than 3 commonly used drugs. The most commonly prescribed prophylactic antibiotics were intravenous Ceftriaxone and Cefuroxime, either singly or in combination with Metronindazole, for a duration of 4-5 (58%) days and 2-3 days (39%). Conclusion: There was a higher proportion of gram negative (73%) than gram positive (27%) bacterial isolates, with high antimicrobial resistance to the commonly used prophylactic antibiotics. The duration of antimicrobial prophylaxis is longer than the recommend for open fractures.