Table 2.
Yield of Investigations performed on patients with meningitis and a negative Gram stain
| New Orleans cohort (N = 205) n (%) |
Houston cohort (N = 118) n (%) |
All cohorts (N = 323) n (%) |
|
|---|---|---|---|
| Viral causes tested | |||
| Positive serum HIV test | 61/140 (43·6) | 14/75 (18·7) | 75/215 (34·9) |
| Any positive viral PCR on CSF* | 14/37 (37·8) | 17/91 (18·7) | 31/128 (24·2) |
| Positive CSF viral culture | 1/121 (0·8) | 0/20 (0) | 1/141 (0·8) |
| Positive arbovirus test in CSF or serum† | 2/42 (4·8) | 13/58 (22·4) | 15/100 (15) |
| Positive CMV IGM serum and negative IgG | 3/63 (4·8) | 1/30 (3·3) | 4/93 (4·3) |
| Positive for lymphocytic choriomeningitis IgM serum | 2/54 (3·7) | 1/22 (4·5) | 3/76 (3·9) |
| Positive EBV IgM serum | 1/29 (3·4) | 2/28 (7·1) | 3/57 (5·3) |
| Bacterial, fungal and other causes tested | |||
| Growth on CSF bacterial culture | 6/205 (2·9) | 7/118 (5·9) | 13/323 (4) |
| Positive blood cultures | 7/149 (4·7) | 8/78 (10·3) | 15/227 (6·6) |
| Positive RPR serum | 1/103 (0·9) | 2/43 (4·6) | 3/146 (2·1) |
| Positive cryptococcal antigen on CSF | 6/88 (6·8) | 2/55 (3·6) | 8/143 (5·6) |
| Positive VDRL on CSF | 1/91 (1·1) | 2/50 (4) | 3/141 (2·1) |
| Growth on CSF fungal culture | 6/90 (6·7) | 2/50 (4) | 8/140 (5·7) |
| Growth on CSF TB cultures | 2/59 (3·4) | 0/47 (0) | 2/106 (1·9) |
| Positive Mycoplasma IgM serum | 2/51 (3·9) | 2/36 (5·5) | 4/87 (4·6) |
| Positive cryptococcal antigen serum | 2/64 (3·1) | 1/23 (4·3) | 3/87 (3·4) |
| Positive for Bartonella serum | 1/45 (2·2) | 1/30 (3·3) | 2/75 (2·6) |
| Positive leptospirosis antibody serum | 0/45 (4·4) | 0/23 (0) | 0/68 (0) |
| Positive Rocky Mountain spotted fever IgM serum | 3/25 (12) | 1/22 (4·5) | 4/47 (8·5) |
| Positive for Ehrlichia (by IFA) serum | 1/28 (3·6) | 0/18 (0) | 1/46 (2·2) |
| Positive CSF BinaxNOW S. pneumoniae | 0/0 (0) | 1/38 (2·6) | 1/38 (2·6) |
PCR, Polymerase chain reaction; CSF, cerebral spinal fluid; CMV, cytomegalovirus; EBV, Epstein–Barr virus; RPR, rapid plasma reagin; VDRL, Venereal Disease Research Laboratory; IFA, immunofluorescence assay.
IFA, Immunofluorescence assay (CSF BinaxNow S. pneumonia; Alere, USA) is a rapid immunochromatographic CSF assay.
Refers to having at least one PCR for either herpes simplex 1 and 2, varicella zoster virus or enterovirus (not all four were checked for every patient).
Included enzyme immunoassay serology for California encephalitis, western and eastern equine encephalitis, St Louis encephalitis, West Nile virus (not all five were tested for every patient).