Table. Results of PCR and serologic tests for rickettsial illness among 416 patients, Chittagong Medical College Hospital, Chittagong, Bangladesh, August 2014–September 2015*.
| Organism and test type | No. positive/no. tested (%) |
|---|---|
| Orientia tsutsugamushi | 70/416 (16.8) |
| Blood PCR, rPCR 47-kDa positive | 45/414 (10.9) |
| nPCR 47 kDa positive | 45/45 (100) |
| nPCR 56 kDa positive | 45/45 (100) |
| Eschar swab, rPCR 47 kDa and n56kDa positive; crust (n = 1), swab (n = 3) | 3/416 (0.7) |
| Indirect immunofluorescence assay | 57/415 (13.7) |
| Admission titer >3,200 | 54/415 (13.0) |
| 4-fold rise to >3,200 | 31/255 (12.1) |
| PCR+ and serology+, 32/70 (45.7% of ST positives) | 32/413 (7.7) |
| PCR+ and serology–, 13/70 (18.6% ST positives) | 13/413 (3.1) |
| PCR– and serology+, 25/70 (35.7% of ST positives) |
25/413 (6.0) |
| Rickettsia spp. | 29/416 (7.0) |
| Blood PCR, rPCR 17 kDa positive | 23/414 (5.6) |
| nPCR 17 kDa positive | 16/23 (69.6) |
| Rickettsia typhi, 24/29 (83.0%) of Rickettsia spp. | 24/416 (5.8) |
| Blood PCR | 17/414 (4.1) |
| rPCR OmpB positive | 12/414 (2.9) |
| nPCR 17-kDa sequencing | 15/16 (93.8) |
| Indirect immunofluorescence assay | 15/415 (3.6) |
| Admission titer >3,200 | 11/415 (2.7) |
| 4-fold rise to >3,200 | 5/255 (2.0) |
| PCR+ and serology+, 8/24 (33.3% of MT positives) | 8/413 (1.9) |
| PCR+ and serology–, 9/24 (37.5% of MT positives) | 9/413 (2.2) |
| PCR– and serology+, 7/24 (29.1% of MT positives) | 7/413 (1.7) |
| Undifferentiated Rickettsia spp., 3/29 (10.3% of Rickettsia spp.) | 3/416 (0.7) |
| rPCR 17-kDa positive, ompB negative | 3/416 (0.7) |
| nPCR 17-kDa negative, gltA negative | 3/416 (0.7) |
| MT serology negative | 3/416 (0.7) |
| Rickettsia felis | 2/416 (0.5) |
| Blood PCR, 17-kDa rPCR and nPCR | 1/416 (0.2) |
| Eschar swab, 17-kDa rPCR and nPCR |
1/416 (0.2) |
| All rickettsial illnesses† | 96/416 (23.1) |
*MT, murine typhus; nPCR, nested PCR; rPCR, real-time PCR; ST, scrub typhus. †Twenty-nine patients had evidence of Rickettsia spp. Infection; 70 had evidence of O. tsutsugamushi infection. Because 2 case-patients had mixed blood O. tsutsugamushi and Rickettsia spp. infections and 1 case-patient with O. tsutsugamushi infection in addition to an eschar-positive swab for R. felis, the total number of rickettsial illness cases was 96.