new_n_lost
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DONT HAVE ANSWER TO THIS EITHER SO ANY CLUES
A 2-year-old girl has had fever and bloody diarrhea for 10 days. A stool culture obtained 7 days ago grew Salmonella species sensitive to amoxicillin. A blood culture was negative. Despite beginning oral amoxicillin therapy 4 days ago, her diarrhea has persisted. Current examination shows no other abnormalities except for a temperature of 38.6 C (101.5 F). Which of the following is the most likely explanation for the failure of amoxicillin to improve her symptoms?
A) Amoxicillin does not alter the course of Salmonella enteritidis
B) Amoxicillin has caused pseudomembranous colitis
C) Amoxicillin is absorbed at the level of the jejunum, leaving no drug to be delivered to the colon
D) Oral amoxicillin is not absorbed into the systemic circulation in the presence of diarrhea
E) Salmonella has expressed an inducible ß-lactamase that inactivates amoxicillin
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| me007
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a.
antibiotic treatment does not shorten the illness or reduce symptoms,
it may prolong excretion of organisms,
incr frequency of carrier state,
and select mutants resistent to antibiotics
from Levinson
also course of disease usually a few days.
what would you do if it would be your pt?
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| new_n_lost
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I wud obviously change the Antiobiotic but the Question here is y the diarrhea is persistent.
My feeling regarding A was that how come An Orgainism which is sensitive to an antibiotic 7 days ago hasnt altered the course of the disease. its n orally administered drug maybe is being less absorbed in th eGut due to diarrhea ??
Can Salmonella develop b-lactamse which is inactivating the drug.
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| po
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found this relevant,
http://pediatrics.aappublications.org/cgi/content...
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| epica
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Ans is E (sure)
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| drmike11
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The answer is C for the reason it lists there. Ampicillin and amoxicillin are both effective against salmonella. Note in the question stem it is given that this strain is sensitive to these beta lactamase antibiotics which rules out choice A and E. B conflicts with choice C since if there is no drug getting past the jejunum it cannot very well cause pseudomembranous colitis (PC). Also, there is no history of moderate to severe abdominal pain ususally associated with PC.
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| new_n_lost
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drMike................ Buddy Pseudo Membranous Colitis is caused by Clostridium Difficile not by Salmonella while administration of Ampicillin/Amoxicillin.
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| drmike11
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new_n_lost wrote:
drMike................ Buddy Pseudo Membranous Colitis is caused by Clostridium Difficile not by Salmonella while administration of Ampicillin/Amoxicillin.
Just to clear things up, Pseudomembranous colitis (2 words not 3) is indeed caused by C. diff and there is no disagreement there. C. diff is a component of the human flora of the large gut. When broad spectrum antibiotics (most notoriously, amp/amox and clindamycin) enter the large gut they tend to kill off other normal flora which uduslly keeps C. diff in check. Once that good flora is killed by the antibiotic, c diff. can run rampant and cause PC. If the drug does not make it to the large gut in sufficent concentration then it cannot wipe out the good flora and so the good flora keeps c. diff in check and there is no PC. Choice C and my above explaination do not contradict this logic.
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| new_n_lost
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drmike11 wrote:
The answer is C for the reason it lists there. Ampicillin and amoxicillin are both effective against salmonella. Note in the question stem it is given that this strain is sensitive to these beta lactamase antibiotics which rules out choice A and E. B conflicts with choice C since if there is no drug getting past the jejunum it cannot very well cause pseudomembranous colitis (PC). Also, there is no history of moderate to severe abdominal pain ususally associated with PC.
SO u R essentially saying that Ampicillin will cause PC n if thats not it then ur reason is that cos of Diarrhea the drug isnt getting absorbed in the intestine. BTW Cud u tell me tht where does Ampicillin/ Amoxicillin get absorbed in the GI anyway.
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| new_n_lost
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And Just for the Sake of Discussion Bloody Diarrhea is commonly a presentation of Colitis or problems of the Large intestine such as IBD or Infectious Cause. this a typical Salmonella Enterocolitis which does mimic IBD. Mostly in Acute settings without much of dehydration the Management of Antibiotics is done PO unless required otherwise. Then Amipicillin can only be resisted by inducing B-lactamases. Now if there were a choice where it wud have said tha tcuase of Persistent Diarrhea is Amipicillin itself then it wud have been the answer but from the Current Questin Choices Provided i wud the best answer wud be Choice E.
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| drmike11
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I'm saying amoxacillin is absorbed well. Whereas ampicillin is poorly absorbed.
If you wanted drug to get to the large gut, use ampicillin since it is poorly absorbed and will remain in the gut the whole way through.
I think this question is testing the concept of amp vs amoxicillin's absorption.
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| Mikeland
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Could help.
Both Amp and amox can cause PC and there is not a significative difc. bet. amoc and amp in absortion both can reach the Large instes. and cause PC. See
http://www.medscape.com/viewarticle/437034_7
"Antibiotics are a common cause of diarrhea. Antibiotics affect the bacteria that normally exist in the large intestine.[15] Broad-spectrum antibiotics kill both the pathogenic and normal colonic flora.[41] A consequence of antibiotic therapy is Clostridium difficile-associated diarrhea (CDAD).[42]C difficile-associated diarrhea occurs because the antibiotic allows the overgrowth of C difficile, which does not typically colonize the colon of a healthy adult.[42] Although most antibiotics can cause CDAD,[15] the antibiotics most commonly associated with CDAD are clindamycin, ampicillin, amoxicillin, and the cephalosporins.[42] Other antibiotics associated with CDAD, but less frequently, include erythromycin, other penicillins, quinolones, and trimethoprim-sulfamethoxazole. Multiple courses of antibiotics or repeated antibiotic therapy increase the risk of infection.[5]C difficile-associated diarrhea can occur as a result of both oral and parenteral antibiotic therapy"
For me asw is "A"
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| webjeee
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Mikeland wrote:Could help. Both Amp and amox can cause PC and there is not a significative difc. bet. amoc and amp in absortion both can reach the Large instes. and cause PC. See http://www.medscape.com/viewarticle/437034_7 "Antibiotics are a common cause of diarrhea. Antibiotics affect the bacteria that normally exist in the large intestine.[15] Broad-spectrum antibiotics kill both the pathogenic and normal colonic flora.[41] A consequence of antibiotic therapy is Clostridium difficile-associated diarrhea (CDAD).[42]C difficile-associated diarrhea occurs because the antibiotic allows the overgrowth of C difficile, which does not typically colonize the colon of a healthy adult.[42] Although most antibiotics can cause CDAD,[15] the antibiotics most commonly associated with CDAD are clindamycin, ampicillin, amoxicillin, and the cephalosporins.[42] Other antibiotics associated with CDAD, but less frequently, include erythromycin, other penicillins, quinolones, and trimethoprim-sulfamethoxazole. Multiple courses of antibiotics or repeated antibiotic therapy increase the risk of infection.[5]C difficile-associated diarrhea can occur as a result of both oral and parenteral antibiotic therapy" For me asw is "A"
so b?
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| monam84
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i agree with me007 its (A), you do NOT use antibiotics against salmonella enteriditis, but you DO you use it for salmonella typhi (present differently with rose spots on abdomen and can lead to carrier status in gallbladder). Note the difference in course of action between the two. Antibiotics used for salm. enteriditis is not appropriate because it prolongs the course of the disease.
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| hanwin
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My answer is A.
It is written in Laurence( Phar TXT)
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| SILVER
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A.
lippincott:- Amox. is completely absorbed so, it isn't appropriate therapy for t/m of salmonella and shigella derived enteritis because therapeautically effective levels do not reach the organisms in the intestinal crypts.
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| new_n_lost
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http://www.cdc.gov/ncidod/dbmd/diseaseinfo/salmon... Read the Article n Comment Plz
Damn the pg is not opening up.
Edited by new_n_lost on 05/10/07 - 11:03 PM
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| ruhighazi
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Salmonella is sensitive to amoxicillin in this patient, so resistance is not the answer(although the mechanism of resistance is plasmid-mediated).The main point is that the antibiotics don’t change the course of the dz.The symptoms are usually self-limited and have not been demonstrated to be altered by short courses of antibiotics.
The diarrhea of Salmonella gastroenteritis may be grossly bloody, lasting 3-5 days. Fever (usually high & often with chills) is the hallmark of dz.
I think this patient does not need antibiotics at all. Bloody diarrhea is the nature of this dz. The treatment of uncomplicated enterocolitis (as in this pt) is symptomatic only. Malnourished or severely ill pts, those with sickle cell dz, and those with suspected bacteremia, pts<3 mo or >50 yr old & immunocompromised pts should be treated for 3-5 days with TMP-SMX, ampicillin or ciprofloxacin.
(Ref: CMDT, 2005 & Harrison’s, 2005, Nelson essential of pediatrics, 2002)
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| jole
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so with everything said and done;is A the answer or E?
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| Addicudo
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Its A then .. !! Good question .. good discussion .. !! 
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| new_n_lost
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well i cant some how feel the answer is E My gut Feeling 
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| sherry39
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ans is eeeee.
3c,s of typhoid....cipro,chlorampheni.,3rd gen cephalo
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| DRFP
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A 2-year-old girl has had fever and bloody diarrhea for 10 days. A stool culture obtained 7 days ago grew Salmonella species sensitive to amoxicillin. A blood culture was negative. Despite beginning oral amoxicillin therapy 4 days ago, her diarrhea has persisted. Current examination shows no other abnormalities except for a temperature of 38.6 C (101.5 F). Which of the following is the most likely explanation for the failure of amoxicillin to improve her symptoms?
A) Amoxicillin does not alter the course of Salmonella enteritidis
B) Amoxicillin has caused pseudomembranous colitis
C) Amoxicillin is absorbed at the level of the jejunum, leaving no drug to be delivered to the colon
D) Oral amoxicillin is not absorbed into the systemic circulation in the presence of diarrhea
E) Salmonella has expressed an inducible ß-lactamase that inactivates amoxicillin
Ampicillin and AMoxicillin are well known to have a side effect of pseudomembranous colitis, All PCN's can do this as well as a lot of the ABX
I think the answer is E though.
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| SmokyWaters
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its E....salmonella acquires resistance very fast...
plus it takes only a day to get induced...
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