Objective: Although the use of prophylactic antibiotics has been shown to significantly decrease the incidence of meningitis after neurosurgery, its effect on extra-neurosurgical-site infections has not been documented. The authors explore the effect of risk-stratified, protocol-based perioperative antibiotic prophylaxis on nosocomial infections in an audit of 31 927 consecutive routine and emergency neurosurgical procedures.
Methods: Infection rates were objectively quantified by bacteriological positivity on culture of cerebrospinal fluid (CSF), blood, urine, wound swab, and tracheal aspirate samples derived from patients with clinicoradiological features of sepsis. Infections were recorded as pulmonary, wound, blood, CSF, and urinary. The total numbers of hospital-acquired infections and the number of patients infected were also recorded. A protocol of perioperative antibiotic prophylaxis of variable duration stratified by patient risk factors was introduced in 2000, which was chosen as the historical turning point. The chi test was used to compare infection rates. A P value of <0.05 was considered significant.
Results: A total of 31 927 procedures were performed during the study period 1994-2006; 5171 culture-proven hospital-acquired infections (16.2%) developed in 3686 patients (11.6%). The most common infections were pulmonary (4.4%), followed by bloodstream (3.5%), urinary (3.0%), CSF (2.9%), and wound (2.5%). The incidence of positive tracheal, CSF, blood, wound, and urine cultures decreased significantly after 2000. Chemoprophylaxis, however, altered the prevalent bacterial flora and may have led to the emergence of methicillin-resistant Staphylococcus aureus.
Conclusion: A risk-stratified protocol of perioperative antibiotic prophylaxis may help to significantly decrease not only neurosurgical, but also extra-neurosurgical-site body fluid bacteriological culture positivity.