Cerebrovascular complications occur in up to 40% of patients with IE.
2 Research has shown that initiation of antibiotic treatment can reduce the rate of neurological complications from 25% to only 6–6.3%,
3 which further highlights the need for rapid diagnosis and treatment of IE.
F hominis is a Gram-positive, alpha-haemolytic, catalase-negative coccus and was the first of the
Facklamia spp. described in 1997.
4 Facklamia spp. resemble viridans streptococci on 5% sheep blood agar and are thought to have previously been wrongly identified as part of this group of organisms.
Of the human clinical specimens that
Facklamia spp. have been isolated from, including blood cultures and cerebral spinal fluid, only one has been reported as from a male. It has been postulated that the female genital tract is the natural habitat of
Facklamia spp., in contrast to
S viridans whose natural habitat is the oropharynx.
5 Facklamia spp. have not previously been associated with IE. While some strains have shown resistance to penicillin, none has demonstrated resistance to vancomycin.
It is interesting to speculate whether this patient had developed the IE earlier at presentation of the first two multi-territory strokes. The previous ECG was re-examined with no evidence of vegetations. One study
6 found a median incubation period for IE of 10 days with the longest period being 2 months. However, the median time to diagnosis was 6 weeks.
Delay in diagnosis was thought to be due to mild and non-specific early manifestations and antibiotic use. During the initial admission, the patient had spiked a temperature and a rising CRP with some coinciding loose stools. It was thought this was due to a viral infection and the CRP did appear to improve. No blood cultures were sent at the time.
But what further complicates the case in retrospect is that there are reports of cases where traditional microbiological methods for microbial identification had incorrectly identified
Facklamia spp. as the causative organism in endocarditis only for 16S rRNA gene sequencing to identify the isolate as
Enterococcus faecalis.7 This raises the possibility that, in the present case, erroneous microbiological identification may have occurred; thereby, influencing the antibacterial treatment. However, whether this would have had an effect on patient prognosis is doubtful, in view of the severe sepsis and co-morbidities.
Nevertheless, this highlights the need for using 16S rRNA gene sequencing and other genetic tools when traditional microbiological identification methods identify pathogens not typically associated with serious infections, such as endocarditis, where misidentification of pathogens has the potential detrimental effect on patient prognosis. However one also has to bear in mind that the genetic tools have their own drawback, such as their cost, which is much greater compared to the traditional methods.
Learning points- IE is an important cause of ischaemic stroke and a high degree of suspicion is required for its timely diagnosis, as its early detection and subsequent initiation of treatment can have a positive impact on the prognosis.
- The finding of IE caused by F hominis in a male patient and the aggressive way in which the patient was affected highlights the need for further study of the Facklamia spp.
- Alpha-haemolytic streptococci isolated from blood cultures are frequently discarded as contaminants; therefore, it also draws to attention the need to consider the addition of Facklamia spp. to commercial rapid identification kits for Gram positive cocci.
- Consider using rRNA gene sequencing and other genetic tools when traditional microbiological identification methods identify pathogens not typically associated with serious infections, such as endocarditis.
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