Emergence ofFrancisella novicidaBacteremia, Thailand

Abstract

We report isolation of Francisella novicida-causing bacteremia in a woman from Thailand who was receiving chemotherapy for ovarian cancer. The organism was isolated from blood cultures and identifi ed by 16S rDNA and PPIase gene analyses. Diagnosis and treatment were delayed due to unawareness of the disease in this region.F rancisella novicida, a rare human pathogen, has recently been considered to be a subspecies of F. tularensis on the basis of DNA similarity (1,2). The reservoir and transmission route of F. novicida were not clearly defi ned. Since the fi rst isolation of F. novicida, to our knowledge, only 5 patients with suspected infection have been reported (3-5). F. novicida, however, has neither been isolated nor associated with human disease in Thailand. We report a case of F. novicida infection in a Thai patient who was undergoing chemotherapy. The StudyIn October 2007, a 37-year-old woman from Thailand sought treatment at Siriraj Hospital (a 2,400-bed university hospital in Bangkok, Thailand) with a history of fever for 1 week. She was a hairdresser residing in a suburban area of Prachuap Khiri Khan, a southern province of Thailand. She denied history of blood transfusion, animal contact, and travel abroad. She had not been aware of being bitten by insects recently. There was no incidence of unusual animal death in the area in which she resided. Five months before seeking treatment, she received a diagnosis of advanced stage clear cell adenocarcinoma of the ovary with metastasis to peritoneum, spleen, uterus, and multiple abdominal lymph nodes. Chemotherapy was planned. Initial laboratory screening showed increased liver enzyme levels and abnormal hepatitis markers confi rming chronic active hepatitis B virus infection. Chemotherapy was delayed while she was treated with lamivudine. A follow-up visit in early September showed that her liver function biochemistry results had returned to within normal limits. Chemotherapy with carboplastin and paclitaxel was then initiated.At the time of admission, 25 days after the start of chemotherapy, the patient had fever (39 o C), blood pressure 90/60 mm Hg, and pulse rate 75 beats/min. She also had an episode of gastrointestinal hemorrhage with melena. It was believed that fever and gastrointestinal bleeding were complications from chemotherapy; thus, microbiologic investigation was not promptly initiated. Abnormal laboratory fi ndings included anemia (hemoglobin 80 g/L) and leukocytosis with marked neutrophilia (Figure). Urine and stool cultures showed insignifi cant growth.Two samples of blood cultures from peripheral lines were obtained using BacT/Alert FA bottles (bioMérieux, Durham, NC, USA) on day 10 of hospital admission and incubated in the continuous monitoring BacT/Alert 3D system (bioMérieux). Both blood culture bottles grew small pleomorphic gram-negative coccobacillus after incubation for 2 days. Samples from positive bottles were subcultured onto 5% (vol/vol) sheep blood agar, MacConkey agar, and chocolate agar. A slow-growing bacterium was recove...

Identification of Francisella tularensis by Whole-Cell Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry: Fast, Reliable, Robust, and Cost-Effective Differentiation on Species and Subspecies Levels

“…We are not aware of any phenotypic identification system showing a similar fast, reliable, and safe performance. Modern, semi-or fully automated identification systems like Phoenix (BD, Heidelberg, Germany) or the Vitek 2 automated microbiology system (bioMérieux, Marcy l'Etoile, France), which are widely used in clinical microbiology, may be able to identify Francisella tularensis strains; however, detailed data on their validity are not published, and misidentification may occur (17). Furthermore, these systems are not able to discriminate between Francisella species or between subspecies of Francisella tularensis.…”

First indication for a functional CRISPR/Cas system in Francisella tularensis

“…novicida strain U112 is a water isolate from 1950 (Larson et al, 1955). There are further reports of several Ft. novicida-like bacteria isolated from humans (Birdsell et al, 2009;Clarridge et al, 1996;Hollis et al, 1989;Leelaporn et al, 2008;Whipp et al, 2003).…”

Subversion of Host Recognition and Defense Systems by Francisella spp

“…LVS causes a very mild infection in humans but can cause a lethal infection in mice and is therefore commonly used as a model to study Francisella pathogenesis. The closely related Francisella novicida species rarely causes disease in humans, though some cases have been documented (31,125). However, F. novicida is highly virulent in mice, has over 98% identity to F. tularensis at the DNA level (188), shares many of the same virulence genes (43), and is also used as a model system to study Francisella virulence.…”