meghana jadhav
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A 45-year-old white male with a history of alcohol abuse and
periodontal disease is brought to the emergency room for a spiking
fever and chills. Physical examination is significant for signs of
lung consolidation. A chest x-ray shows a cavity in the right
lower lobe that has an air/fluid level. A transtracheal aspiration
is performed and the specimen is submitted to the laboratory for
routine cultures and Gram's stain. Based upon the clinical
presentation, which of the following would be the most likely finding?
A. Anaerobic bacteria
B. Aspergillus fumigatus
C. Entamoeba histolytica
D. Staphylococcus aureus
E. Streptococcus pyogenes
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megha
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| mjl1717
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anaerobic bacteria?
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| bactitech
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I am guessing anaerobic bacteria. However, please realize that, in real life, NOBODY performs transtracheal aspirations any more. I have worked in microbiology since 1974. I've seen maybe one in my lifetime, and that was back in 1974. It is a very risky procedure to perform. Usually, they'll do bronch washes, BAL's (bronchial alveolar lavage) sometimes with a protected brushing (the brush itself is sent for culture - it's the only thing we'll culture for anaerobes out of a respiratory specimen other than an actual aspirate in a syringe taken in surgery from an abscess) if they want to get a good specimen, but never a transtrach.
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| meghana jadhav
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yup
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megha
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| Malaysian
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This is lung abscess due to anaerobic bacteria.
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| mdwannabe
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sounds like actino. so G- !
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| mdwannabe
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and anaerobic
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| bactitech
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Actinomyces is a gram positive rod, NOT a gram negative. Bacteroides and Prevotella (formerly Bacteroides) are anaerobic gram negative rods. Lung abscesses can be due to many organisms from the mouth (the peridontal disease factor mentioned in the question) many of which are gram positive. These abscesses are mixed infections many times, although Bacteroides and sometimes Fusobacterium sp. (another anaerobic gram negative that can be found in the mouth) are also present. These organisms really stink - literally. I work on anaerobic cultures a lot and see Bacteroides in various cultures almost daily. Actino can be present, theoretically, but it's not one I see very often.
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| Renegade
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I agree with that; I wasn't sure about the Entamoeba but I'd go for anaero because of periodontal disease. However, what about the alcohol? Is it in any way connected to the disease :?: ...
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| bactitech
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Probably nothing more than that many alcoholics have lousy teeth. Their nutrition is bad, which leads to crummy gums ---> peridontal disease.
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| bactitech
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You wouldn't be seeing Entamoeba in a respiratory infection. That would either been in stool or a liver biopsy.
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| mani
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alcoholics are more prone to aspiration
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| mdwannabe
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I am sure it is actino. So anaerobe would be sufficient. None of the others fit the picture...the full picture that is.
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| bactitech
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http://www.ecureme.com/emyhealth/data/Lung_Absces...
http://www.chclibrary.org/micromed/00055380.html
http://www.emedicine.com/med/topic1332.htm
Please note that the last site says the following:
"In lung abscesses, anaerobes are recovered in up to 89% of the patients. In a study by Bartlett et al in 1974, 46% of patients with lung abscesses had only anaerobes isolated from sputum cultures while 43% of patients had a mixture of anaerobes and aerobes. The most common anaerobes are Peptostreptococcus, Bacteroides, Fusobacterium species, and microaerophilic streptococcus.
Other organisms that may infrequently cause lung abscess include Staphylococcus aureus, Streptococcus pyogenes, Streptococcus pneumoniae (rarely), Klebsiella pneumoniae, Haemophilus influenzae, Actinomyces species, Nocardia species, and gram-negative bacilli."
Actinomyces is listed as an INFREQUENT cause, and the organisms I listed are more common. Sorry, but I don't want you guys to come away with the wrong ideas. I work on these cultures all the time. We really don't see Actino very often.
As a footnote to this discussion, my husband was put on beta blockers for his high BP back in th early 80's. In the spring of '82, all of us were sick with URI's. Our daughter was 2 at the time, and we all grew Hemophilus influenzae from various sources. In May, my husband had a "routine" chest x-ray (they used to do those back then :-)) and they saw a shadow on his lung. Since he was a smoker at the time (2 packs a day, but he was only 31 years old then) he was sure it was cancer and quit cold turkey (thank goodness). I didn't think so, as he didn't have enough "pack years" under his belt for CA. The docs fooled around all summer and finally did a needle biopsy through his chest wall, as the spot didn't change in size. He was not sick at all, but his breath smelled bad. The aspirate grew Hemophilus influenzae. They figured that he got it because beta blockers are a broncho-constrictor and he has a touch of asthma. They put him on ampicillin IV (most of them were sensitive to it back then - not so now) and later by mouth for at least a month. They changed his BP meds and he was fine with no sequelae. His doctor was dumbfounded and couldn't believe that it was H. influenzae, as these are usually caused by anaerobes.
He still has high BP, but has never taken up smoking since.
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| fox
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Alcoholic with lung abscess....I think klbesiella would be the organism...especially given the cavitatory lesion. here is a reference from e-medicine:
Chest radiography
The organism usually involves one of the upper lobes; however, involvement of lower lobes is not uncommon.
The affected lobe typically appears swollen, producing the bulging fissure sign. This presentation is not necessarily exclusive to Klebsiella infection. Other organisms, such as H influenzae, may produce a similar radiographic appearance.
Cavitation, especially in the presence of a unilateral necrotizing pneumonia, strongly supports the possibility of a Klebsiella organism as the etiologic agent.
Pleural effusion, empyema, abscess formation, and pleural adhesions occur with increased frequency in patients with Klebsiella pneumonia.
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| bactitech
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Klebsiella is not one of the choices. It's also not an anaerobe. It is a lactose fermenting member of enterobacteriaceae.
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