Analysis of microbial etiology and mortality in patients with brain abscess.
OBJECTIVE
Despite the technological advancements in diagnostic and neurosurgical procedures, brain abscess continues to remain a potentially fatal central nervous system infection. In a prospective study we determined the predisposing factors and the microbiological profile of brain abscess. We also analyzed the mortality in patients with the type of infections identified.


METHODS
Over a period of 8 years (1997-2004), aspirated pus from 118 patients with brain abscess was directly inoculated into BACTEC PLUS+ aerobic and BACTEC PLUS+ anaerobic media immediately after collection and subcultured on solid media as appropriate. Predisposing factors, if any, were recorded in all patients. Mortality of patients during hospital stay was correlated with the type of infections identified.


RESULTS
Predisposing factors were identified in 94 (79.7%) patients, otogenic infection being the most common (37/118; 31.4%). Microorganisms were demonstrated in 96 (81.4%) patients, by culture in 89 (75.4%) patients and by Gram stain in 7 (5.9%) additional cases. A total of 105 organisms were isolated - 67 (63.8%) aerobes, 32 (30.5%) anaerobes, 5 (4.8%) mycobacteria and 1 (0.9%) fungus. Viridans streptococci (23.8%), Staphylococcus aureus (14.3%), Bacteroides fragilis group/species and Peptostreptococcus species (10.5% each) were the common isolates. Overall mortality was 14.4%; patients with Gram-negative infections had higher mortality than Gram-positive infections (6/20; 30% vs. 6/63; 9.5%; P=0.02).


CONCLUSIONS
Culture of pus immediately after aspiration in an automated system yields good results. Gram stain coupled with culture can guide the neurosurgeons better to treat their patients more rationally. Patients with Gram-negative infections need special attention in terms of management because of high mortality rate.
Prasad
Kashi N
KN
Department of Microbiology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, Uttar Pradesh 226014, India. knprasad@sgpgi.ac.in
Mishra
Asht Mangal
AM
Gupta
Deepti
D
Husain
Nuzhat
N
Husain
Mazhar
M
Gupta
Rakesh K
RK
D000293:Adolescent; D000328:Adult; D001420:Bacteria, Aerobic / Q000145:classification / Q000302:isolation & purification; D001421:Bacteria, Anaerobic / Q000145:classification / Q000302:isolation & purification; D001424:Bacterial Infections / Q000382:microbiology / Q000401:mortality; D001922:Brain Abscess / Q000382:microbiology* / Q000401:mortality*; D002648:Child; D002675:Child, Preschool; D003470:Culture Media; D005260:Female; D006090:Gram-Negative Bacteria / Q000145:classification / Q000302:isolation & purification; D006094:Gram-Positive Bacteria / Q000145:classification / Q000302:isolation & purification; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D012307:Risk Factors
D003470:Culture Media