The bacteriology of open fractures in Ile-Ife, Nigeria

Abstract

Background: The objective of this study is to determine the pattern of bacterial isolates and antibiotic sensitivity profile in open fractures. Fifty-nine patients with open fractures of the lower limb long bones were studied. The majority of the cases were Gustilo and Anderson types II 21(35.6%), and IIIA 16(27.1%).

Method: The patients were assessed by history taking, physical examination, and plain radiographs. Wound swabs were taken for bacteriological studies. Other necessary investigations were also done. During wound debridement open fractures were classified into Grades I, II and III using the Gustilo-Anderson method of classification.

Results: The infection rate was 45.8%. Gram-positive cocci and Gram-negative rods were isolated. On the whole Staphylococcus aureus 13(25%), and Coagulase-negative staphylococci (CONS) 14(26.9%), were the commonest organisms isolated. The commonest Gram-negative rods that were isolated from the wounds were Proteus mirabilis 9(17.3%), and Pseudomonas aeruginosa 8(15.4%). Multiple organisms were commonly isolated from the wounds. While all the organisms isolated showed very good sensitivity to gentamicin, cloxacillin and ofloxacin, most of the organisms were resistant to penicillin, ampicillin and tetracycline. The sensitivity ranged from 62.5% to 100%. Coagulase-negative Staphylococci (CONS) showed sensitivity to the widest range of antibiotics which included penicillin, ampicillin, chloramphenicol, gentamicin, cloxacillin and ofloxacin. The sensitivity ranged from 35.7% to 100%. There was statistically significant difference between the open tibial and femoral fracture cases with respect to the interval between injury and debridement time (p = 0.008); the rate of wound infection (p = 0.021); and the occurrence of osteomyelitis (p = 0.023). The commonest complications observed were wound infection 27(45.8%), and delayed fracture union 26(44.1%), which were commoner in the open tibial fractures.

Conclusion: This study shows that Staphylococcus aureus and coagulase-negative staphylococci (CONS) were the commonest organisms associated with open fracture of the lower limbs in our centre and that delay in the initial wound debridement was a major predisposing factor to wound infection.