Bacterial etiology of chronic osteomyelitis involving anaerobes

Abstract EN

Objective : to identify common bacterial causes in chronic osteomyelitis, to verify the role of anaerobic microorganisms in chronic osteomyelitis, and to assess the reliability of swab from discharging sinuses, and from abscess aspirate in chronic osteomyelitis.

Material and Methods : the study included 184 patients suffering from chronic osteomyelitis, 141 males and 43 females, ranging in age between 4-78 years with mean 40.5 years.

The patients presented with chronic discharging sinus in 152 patients or acute flare up in 32 patients ; they were divided according to causes into two broad categories haematogenous in 52 patients and exogenous in 132 patients.

Specimens were taken from infected bone debridement during surgery, other specimens taken from sinus discharge or aspirated from bone abscesses.

All specimens were inoculated on different culture media and incubated both aerobically and anaerobically.

Results : the majority of cases of chronic osteomyelitis involved long bones specially the femur and tibia (64.6 %).

Aerobic microorganisms were found in 134 patients (73 %), staph.

aureus and pseudomonas were the commonest aerobic isolates.

In fifty cases (27 %), the causative microorganisms were anaerobic.

Anaerobes were found to be mixed with aerobes in 34 cases (68 %), while pure anaerobes were obtained in 16 cases (32 %).

Peptostreptococcus and Bacteroides were the dominant anaerobic isolates.

The reliability of culture of abscesses aspirate in comparison with bone debridement culture is 93.3 %.

The reliability of culture of sinus discharge in comparison with bone debridement culture is 42.7 %, while for anaerobic infection is 26 %.

Conclusion : chronic osteomyelitis commonly affect adult males in long bones.

The exogenous causes were the commonest.

Aerobic isolates were the major cause, and anaerobic bacteria were an important other causative agents.

Anaerobes usually isolated in prolonged persistent infection and pure anaerobes in older patients.

The cultures of aspirate from bone abscesses were reliable way in diagnosis, while cultures from discharging sinuses had low diagnostic reliability and lower for anaerobic infection.