Case StudyCase StudyPathogenic BacteriologyPathogenic Bacteriology

20092009

Case # 65Case # 65Maria NavarreteMaria Navarrete

Luu, HelenLuu, HelenChiu, AllenChiu, Allen

Case SummaryCase Summary

The patient was am 8-year-old male with a 2-day The patient was am 8-year-old male with a 2-day history of diarrhea. He presented with worsening history of diarrhea. He presented with worsening diarrhea (14 movements that day) which had become diarrhea (14 movements that day) which had become bloody. He also complained of pain upon defecation bloody. He also complained of pain upon defecation and had vomited once. He had attended a cookout and had vomited once. He had attended a cookout previously and claimed that his mother had made him previously and claimed that his mother had made him eat a hamburger that was “pink inside” even though eat a hamburger that was “pink inside” even though he” he did not like it.” he” he did not like it.”

Culture of stool specimen on Culture of stool specimen on MacConkey-sorbitol MacConkey-sorbitol

Key Information Pointing to DiagnosisKey Information Pointing to Diagnosis

AgeAge - 8-year old- 8-year old

SymptomsSymptoms 2-day diarrhea2-day diarrhea Bloody diarrheaBloody diarrhea VomitVomit DehydrationDehydration Pain upon defecationPain upon defecation

HistoryHistory Consumption of undercooked meatConsumption of undercooked meat

Physical examinationPhysical examination White blood count of 13, 100/μl with 9,700 neutrophils per μlWhite blood count of 13, 100/μl with 9,700 neutrophils per μl Abundant polymorphonuclear cells in a methylene blue stain of fecesAbundant polymorphonuclear cells in a methylene blue stain of feces He was treated with trimethoprim-sulfamethoxazole and intravenous fluid He was treated with trimethoprim-sulfamethoxazole and intravenous fluid

therapy for dehydration. His condition improved and was discharged 24 hours therapy for dehydration. His condition improved and was discharged 24 hours later.later.

DiagnosisDiagnosis

EnterohemorrhagicEnterohemorrhagic

Escherichia coli Escherichia coli serotype serotype O157:H7O157:H7

InfectionInfection

EnterobacteriaceaeEnterobacteriaceae Escherichia coli Escherichia coli serotypeserotype O157:H7 O157:H7 Enterohemorragic (EHEC)Enterohemorragic (EHEC) Gram –Gram – RodRod MotileMotile Sorbitol negative Sorbitol negative

ClassificationClassification

www.mikerickman.com/ www.mikerickman.com/

Diseases and Pathogenesis of Disease Diseases and Pathogenesis of Disease Caused by Pathogen Caused by Pathogen E. coli O157:H7E. coli O157:H7

DiseasesDiseases Hemorrhagic diarrheaHemorrhagic diarrhea ColitisColitis Hemolytic-uremic syndrome (HUS)Hemolytic-uremic syndrome (HUS)

PathogenesisPathogenesis E. coli O157:H7 E. coli O157:H7 has O, H, antigens.has O, H, antigens. E. coli O157:H7 produces two toxins: verotoxin I and verotoxin II.E. coli O157:H7 produces two toxins: verotoxin I and verotoxin II.

Verotoxin I is a phage-encoded cytotoxin identical to the shiga toxin.Verotoxin I is a phage-encoded cytotoxin identical to the shiga toxin. E. coli O157:H7 E. coli O157:H7 attaches via pili to the intestinal mucosa and liberates attaches via pili to the intestinal mucosa and liberates

the shiga-like toxin.the shiga-like toxin.

Diagnosis/Isolation/Identification/ of Diagnosis/Isolation/Identification/ of E. coli O157:H7E. coli O157:H7

Stool culture on MacConkey agar containing sorbitol Stool culture on MacConkey agar containing sorbitol (SMAC)(SMAC) Appear colorless with heavy growthAppear colorless with heavy growth

Serotyping with Serotyping with E. coli O157:H7E. coli O157:H7 antiserum antiserum 4-methylum-belliferyl 4-methylum-belliferyl ββ-D-glucoronide (MUG) biochemical -D-glucoronide (MUG) biochemical

testtest E. coli O157:H7 rarely produces the enzymeE. coli O157:H7 rarely produces the enzyme ββ-D--D-

glucoronidase; therefore, if enzyme is present a glucoronidase; therefore, if enzyme is present a fluorescent product is formed.fluorescent product is formed.

ELISA or latex agglutination to detect O157 antigenELISA or latex agglutination to detect O157 antigen Latex test to detect H7 antigenLatex test to detect H7 antigen

Therapy, Prevention and Prognosis of Therapy, Prevention and Prognosis of Patient Infected with Patient Infected with E. coli 0157:H7E. coli 0157:H7

Most people recover without specific treatment in five to 10 days. Antibiotics Most people recover without specific treatment in five to 10 days. Antibiotics should not be used for the treatment of should not be used for the treatment of E. coli 0157:H7E. coli 0157:H7 infection due that infection due that some antibiotics may increase the risk of complications.some antibiotics may increase the risk of complications.

To prevent To prevent E. coli 0157:H7E. coli 0157:H7 infections, do not eat undercooked hamburger or infections, do not eat undercooked hamburger or other ground beef products. Drink only pasteurized milk, juice or cider. other ground beef products. Drink only pasteurized milk, juice or cider. Wash fruits and vegetables thoroughly, especially those that will not be Wash fruits and vegetables thoroughly, especially those that will not be cooked. cooked.

Children under five years and the elderly should avoid eating alfalfa sprouts. Children under five years and the elderly should avoid eating alfalfa sprouts. Immunocompromised patients are also susceptible to Immunocompromised patients are also susceptible to E. coli 0157:H7.E. coli 0157:H7.

People who are infected with People who are infected with E. coli 0157:H7E. coli 0157:H7, especially children, should , especially children, should wash their hands carefully with soap after using the toilet to reduce the risk wash their hands carefully with soap after using the toilet to reduce the risk of spreading the disease.of spreading the disease.

Prevalence and potential link between Prevalence and potential link between E. coli O157:H7 E. coli O157:H7 isolated isolated from drinking water, meat and vegetables and stools of from drinking water, meat and vegetables and stools of diarrhoeic confirmed and non-confirmed HIV⁄AIDS patients diarrhoeic confirmed and non-confirmed HIV⁄AIDS patients in the Amathole District – South Africain the Amathole District – South Africa Abong’o B.O et al, 2008, Journal of Applied Microbiology, Abong’o B.O et al, 2008, Journal of Applied Microbiology, volvol:105. p-p. :105. p-p.

424–431.424–431. Stool collection from confirmed and non-confirmed patients from a referral Stool collection from confirmed and non-confirmed patients from a referral

hospital in The Amathole district in Africa were tested for hospital in The Amathole district in Africa were tested for E. coli E. coli O157:H7. O157:H7. Water samples and meat samples collected from rural Water samples and meat samples collected from rural communities incommunities in The Amathole district where these patients reside were The Amathole district where these patients reside were collected and tested for the presence of collected and tested for the presence of E. coli O157:H7.E. coli O157:H7.

Researchers found that 74 out of 131 stool samples of HIV/AIDS patients Researchers found that 74 out of 131 stool samples of HIV/AIDS patients contained contained E. coli O157:H7.E. coli O157:H7. They also found that 46 out of 180 water They also found that 46 out of 180 water samples contained and 64 out of 180 meat and meat products samples samples contained and 64 out of 180 meat and meat products samples contained contained E. coli O157:H7.E. coli O157:H7.

Researchers also fount that the prevalence of Researchers also fount that the prevalence of E. coli O157:H7 wE. coli O157:H7 was as correlated to the poor living and unhygienic of these patients. correlated to the poor living and unhygienic of these patients.

Researchers urge for prompt monitoring of water and food products in Researchers urge for prompt monitoring of water and food products in underserved communities to control underserved communities to control E. coli O157:H7 E. coli O157:H7 infections.infections.

This article was important for the prevention of This article was important for the prevention of E. coli O157:H7 in HIV E. coli O157:H7 in HIV patients living in underserved communities.patients living in underserved communities.

Take Home MessageTake Home Message

E. coli 0157:H7E. coli 0157:H7 causes hemorrhagic diarrhea, colitis, and HUS. causes hemorrhagic diarrhea, colitis, and HUS. E. coli 0157:H7 illness produces watery diarrhea, bloody diarrhea, abdominal E. coli 0157:H7 illness produces watery diarrhea, bloody diarrhea, abdominal

cramps, and a low grade fever or no fever.cramps, and a low grade fever or no fever. E. coli 0157:H7 may be potentially fatal for young children and the elderly.E. coli 0157:H7 may be potentially fatal for young children and the elderly. E. coli 0157:H7 may be identified by stool culture using SMAC, serotyping, and E. coli 0157:H7 may be identified by stool culture using SMAC, serotyping, and

detection of shiga-like toxins.detection of shiga-like toxins. Antibiotics should not be used for the treatment of Antibiotics should not be used for the treatment of E. coli 0157:H7E. coli 0157:H7 infection due infection due

to higher production of shiga-like toxin.to higher production of shiga-like toxin. Cook all meat thoroughly, wash all vegetables, and do not drink unpasteurized Cook all meat thoroughly, wash all vegetables, and do not drink unpasteurized

dairy products and juices.dairy products and juices. Transmission of Transmission of E. coli 0157:H7 is through the consumption of undercooked E. coli 0157:H7 is through the consumption of undercooked

processed meat, unpasteurized dairy products and juices, and bean sproutsprocessed meat, unpasteurized dairy products and juices, and bean sprouts . . E. coli 0157:H7 is an important potential human pathogen.E. coli 0157:H7 is an important potential human pathogen.

ReferencesReferences

Abong’o, B. O., and M. N.B. Momba. "Prevalence and potential link Abong’o, B. O., and M. N.B. Momba. "Prevalence and potential link between between E. coli O157:H7E. coli O157:H7 isolated from drinking water, meat and isolated from drinking water, meat and vegetables and stools of diarrhoeic confirmed and non-confirmed vegetables and stools of diarrhoeic confirmed and non-confirmed

HIV⁄AIDS patients in the Amathole District – South Africa." HIV⁄AIDS patients in the Amathole District – South Africa." Journal Journal of Applied Microbiologyof Applied Microbiology 105 (Jan.-Feb. 2008): 424–431. 105 (Jan.-Feb. 2008): 424–431.

Centers for Disease Control and Prevention. "Centers for Disease Control and Prevention. "Escherichia coliEscherichia coli General General Information ." Information ." Centers for Disease Control and PreventionCenters for Disease Control and Prevention. 27 Mar. 2008.. 27 Mar. 2008. Department of Health and Human Services. 11 Mar. 2009 Department of Health and Human Services. 11 Mar. 2009 <http://www.cdc.gov/nczved/dfbmd/disease_listing/stec_gi.html>. <http://www.cdc.gov/nczved/dfbmd/disease_listing/stec_gi.html>.

Mahon, Connie R., Donald C. Lehman, and George Manuselis. Mahon, Connie R., Donald C. Lehman, and George Manuselis. Diagnostic MicrobiologyDiagnostic Microbiology. 3rd ed. St. Louis: Saunders, 2007. . 3rd ed. St. Louis: Saunders, 2007.

McQueen, Nancy. "Enterobacteriaceae." Unpublished notes. CaliforniaMcQueen, Nancy. "Enterobacteriaceae." Unpublished notes. California State University Los Angeles. Biology and Microbiology State University Los Angeles. Biology and Microbiology Department. Winter 2009.Department. Winter 2009.

Rickman, Mike. "A Colorful Editorial Cartoon Accompanying a Column About an Rickman, Mike. "A Colorful Editorial Cartoon Accompanying a Column About an E. coliE. coli Outbreak." Cartoon. Outbreak." Cartoon. Mike RickmanMike Rickman. 11 Mar. 2009 <http://www.mikerickman.com/mike/illustration/ . 11 Mar. 2009 <http://www.mikerickman.com/mike/illustration/

index.shtml>. index.shtml>.