anne
Forum Elite
Topics: 41
Posts: 348
|
A 34-year-old HIV-infected patient is admitted for fever of unknown origin and is noted to have a new heart murmur. Physical findings include splinter hemorrhages, Janeway lesions, and focal neurological findings. Blood cultures are obtained but no organisms are found. What is the organism most likely to be causing this patient's endocarditis?
A. Eikenella
B. N. gonorrhoeae
C. S. aureus
D. S. pneumoniae
E. T. cruzi
|
| usmleasr
Forum Guru
Topics: 105
Posts: 970
|
C.s.aureus :roll:
|
| anne
Forum Elite
Topics: 41
Posts: 348
|
the answer is A,but we'll have to figure out how 
|
| asmi
Forum Hero
Topics: 1043
Posts: 4,609
|
:roll:
|
| elsa
Forum Junior
Topics: 5
Posts: 46
|
The answer is Eikenella.Infective endocarditis include acute and subacute bacterial endocarditis as well as nonbacterial endocarditis.Staph aureus is the leading case of endocarditis in pediatric patient. Staph endocarditis is most common in patient with no underlying heart disease. Viridans group strep is common after dental procedure. Grp D enterococci are seen after lower bowel or genitourinary manipulation. Pseudomonas aureginosa or serratia mercescens is seen on IV drug user. Eikenella corrodens belong to HACEK organism. This are group of gram negative rods that have in common.
1. they are slow growth in culture
2. They have an ability to case endocarditis
Eikenella corroden is also a normal flora of the oral cavity. THe patient in this case is immunocompromise.
H- Haemophilus aphrophilus and H. paraphophilus
A- actinomycete concomitans
C-cardiobacterium
E- Eikenella corrodens
K- kingella kingae
___________________
elsa
|
| piter
Forum Elite
Topics: 34
Posts: 191
|
elsa your explanation is great!
|
| Idiopathic
Forum Guru
Topics: 19
Posts: 641
|
W/HIV Px you have to assume IV drug user and it would almost have to be S. Aureus. I am not saying your explanation is wrong, but the whole HACEK group only accounts for about 8% of endocarditis.
As I write this, I remember something Goljan told us just yesterday...IV drug users can have a risk of Eikenella if they lick their needles before injecting...interesting. I would still say s. aureus over all others, but thats just me.
|
| asmi
Forum Hero
Topics: 1043
Posts: 4,609
|
cool,thanks idio and elsa
|
| bactitech
Forum Elite
Topics: 25
Posts: 496
|
On plates, Eikenella usually takes 2 days to show up. Its colony morphology is very typical and is easily identified by commercial systems, but you can presumptively ID it by colony morphology and positive oxidase testing.
I can't tell you the last time I saw E. corrodens in a blood culture. I usually see them in abscesses with some sort of "oral" origin (human bite wounds....).
I would imagine, however, that most commercial blood culture systems would be able to grow this organism if it were present in the blood, as they are extremely sensitive to any growth in the bottles. The broths in the commercial systems are pretty "souped up" to accommodate growth of extremely fastidious organisms.
If one would suspect this organism, please let the lab know. The standard hold time for blood cultures is now pretty much 5 days everywhere. We can change that easily to a longer period if fungi or weird stuff is suspected by a few buttons pushed on the machine to incubate longer. We hold fungal bloods 14 days - more than enough time for E. corrodens to show up.
Call micro and let them know if you're suspecting fastidious bugs.
___________________
Clinical Microbiology since 1974
|
| Malaysian
Forum Guru
Topics: 28
Posts: 778
|
whats staph. endocarditis?
|
| bactitech
Forum Elite
Topics: 25
Posts: 496
|
Endocarditis caused by Staphylococci.
http://www.helenacardiology.com/photo%20album/pat...
http://home.coqui.net/myrna/myocar.htm
I found this stuff on google in less than a minute :-).
___________________
Clinical Microbiology since 1974
|
|
| |
| | | | | | | | | | | |
