TABLE 1.
Clinical characteristics of 4 patients with Francisella tularensis PJIs
| Characteristica | Data by case no., countryb
|
|||
|---|---|---|---|---|
| 1, Switzerland (23) | 2, Czech Republic | 3, Ontario, Canada (2) | 4, Illinois, USA (3) | |
| Age (yr), sex | 84, female | 84, male | 68, male | 77, male |
| Yr of presentation | 2016 | 2016 | 1999 | 2017 |
| Affected joint | Knee | Knee | Knee | Hip |
| Immunosuppression | No | No | Rheumatoid arthritis (methotrexate) | No |
| Previous infection of affected joint | No | E. coli PJI infection 8 years prior, cured with DAIR | Enterococcus faecalis PJI, cured | No, but recent (7 days) revision THR due to pain and limited range of movement |
| Potential source of acquisition | Housing of rabbits in next-door house (infected dust?) | No apparent exposure, but abdominal symptoms prior to joint effusion are suggestive of intestinal tularemia | Hunter, tick bite 6 mo before arthroplasty | Hunter, no tick bite |
| Time to diagnosis after previous surgical intervention/revision | 12 years | 8 years | 6 months | 25 years; bullous lesion on shin 1 yr before onset of symptoms |
| Clinical findings | Erythema, joint pain, no fever | Fever, abdominal pain, confusion, painful knee effusion | Discharge from joint, no fever | Fever, joint pain |
| CRP concn (mg/liter) | 81 | 98 | NA | 16 |
| ESR (mm/h) | 69 | NA | 47 | 96 |
| Microbiology | ||||
| Positive culture status | Yes (6 out of 7), thioglycolate broth; sonication negative | Yes, Columbia 5% sheep blood agar | Yes, chocolate agar | Yes (out of 2), Vitek cultures |
| Type of sample | Tissue cultures | Joint aspiration | Joint aspiration | Joint aspiration |
| Days of cultivation until growth | 12 (blind subculture) | 4 | 3 | 7 |
| Molecular method | 16S rRNA gene and specific PCR negative in tissue sample; 16S rRNA gene sequencing of growing pathogen positive | 16S rRNA gene PCR and sequencing of the colonies grown on agar | Culture sequencing; F. tularensis tularensis bv. type B | NA |
| Serology result for F. tularensis | IgM, 232.6 U/ml (N, <10 U/ml); IgG, 126.4 U/ml (N, < 0 U/ml) | 1:80 titer (microagglutination) | 1:320 titer (microagglutination) | Results reported as positive from the lab without stating any titers |
| Finding in histopathology | Acute inflammation, wear of prosthesis | NA | NA | NA |
| Surgical treatment | 2-stage revision joint replacement | Repeated aspiration only | 2-stage revision joint replacement | DAIR |
| Antibiotic treatment | 6 wk; 100 mg doxycycline twice daily | 3 wk and 3 wk; 20 days of 100 mg doxycycline bd plus 10 days of 240 mg gentamicin od, followed by 20 days of 500 mg ciprofloxacin bd | 6 mo; ciprofloxacin-rifampin (unknown dose), initially no response to ciprofloxacin in monotherapy | 12 mo; 100 mg doxycycline bd |
| Cure (time to follow-up) | 2 years | 2 years | >6 months | 1 year |
| No. of healthcare workers who took postexposure antibiotic prophylaxis | 0 | 7 | Unknown | Unknown |
a
CRP, C-reactive protein; ESR, erythrocyte sedimentation rate; N, normal.
b
DAIR, debridement, antibiotics, implant retention; THR, total hip replacement; NA, not available; bd, twice daily; od, once daily.