E. coli

Background

This is one of the most common bacterial infections in man. It has garnered recent noteriety because of infected beef in the United States.

OUTLINE

Epidemiology

Disease Associations

Pathogenesis

Laboratory/Radiologic/Other Diagnostic Testing

Gross Appearance and Clinical Variants

Histopathological Features and Variants

Special Stains/Immunohistochemistry/Electron Microscopy

Differential Diagnosis

Prognosis and Treatment

Commonly Used Terms

EPIDEMIOLOGY CHARACTERIZATION

SYNONYMS

INCIDENCE

AGE RANGE-MEDIAN

SEX (M:F)

GEOGRAPHY

DISEASE ASSOCIATIONS CHARACTERIZATION

HEMOLYTIC UREMIC SYNDROME

PATHOGENESIS CHARACTERIZATION

LABORATORY/RADIOLOGIC/
OTHER TESTS
CHARACTERIZATION

RADIOLOGIC

LABORATORY MARKERS

PCR

Comparison of DNA hybridization and PCR assays for detection of putative pathogenic enteroadherent Escherichia coli.

Scaletsky IC, Fabbricotti SH, Aranda KR, Morais MB, Fagundes-Neto U.

Department of Microbiology, Immunology, and Parasitology, Universidade Federal de Sao Paulo, Escola Paulista de Medicina, Sao Paulo, SP, Brazil CEP 04023-062.
J Clin Microbiol 2002 Apr;40(4):1254-8 Abstract quote
The correlation of the different adherence patterns with DNA probes and PCR primers for the identification of Escherichia coli was analyzed in isolates from children, less than 2 years of age with or without diarrhea, from different regions of Brazil. A total of 1,428 isolates obtained from 338 patients and 322 control children were studied. The enteropathogenic E. coli (EPEC) adherence factor (EAF) probe was shown to be as good as the HEp-2 adhesion assay for the detection of typical EPEC strains. The DNA probes used to detect diffusely adhering E. coli and enteroaggregative E. coli (EAEC) showed low sensitivities (64 and 50%, respectively), and the best method of identifying these organisms in clinical research remains the HEp-2 adherence assay.

The "bundle-forming pilus" (BFP) and the EAEC PCR assays could be used instead of the DNA probes as a screening method for typical EPEC and EAEC carrying the EAEC probe sequence in the clinical laboratory. In our study, only typical EPEC strains that carried EAF and BFP were associated with acute diarrhea.

GROSS APPEARANCE/
CLINICAL VARIANTS CHARACTERIZATION

GENERAL

VARIANTS

INFANCY

Virulence factors of Escherichia coli isolated from female reproductive tract infections and neonatal sepsis.

Cook SW, Hammill HA, Hull RA.

Department of Biology, Houston Baptist University, TX, USA.
Infect Dis Obstet Gynecol 2001;9(4):203-7 Abstract quote
OBJECTIVE: The presence of enterobacteria such as Escherichia coli in the vagina of normal women is not synonymous with infection. However, vaginal E. coli may also cause symptomatic infections. We examined bacterial virulence properties that may promote symptomatic female reproductive tract infections (RTI) and neonatal sepsis.

METHODS: E. coli isolated as the causative agent from cases of vaginitis (n = 50), tubo-ovarian abscess (n = 45) and neonatal sepsis (n = 45) was examined for selected phenotypic and genetic virulence properties. Results were compared with the frequency of the same properties among fecal E. coli not associated with disease.

RESULTS: A significantly greater proportion of infection E. coli exhibited D-mannose resistant hemagglutination compared with fecal E. coli (p < 0.01). This adherence phenotype was associated with the presence of P fimbriae (pap) genes which were also significantly more prevalent among isolates from all three infection sites (p < 0.01). The majority of pap+ isolates contained the papG3 allele (Class II) regardless of infection type. Increased frequency of Type IC genes among vaginitis and abscess isolates was also noted. No significant differences in frequency of other bacterial adherence genes, fim, sfa, uca (gaf or dra were observed. E. coli associated with vaginitis was significantly more likely to be hemolytic (Hly+) than were fecal isolates (p < 0.05). The Hly+ phenotype was also more prevalent among tubo-ovarian abscess and neonatal sepsis isolates (p < 0.08).

CONCLUSIONS: E. coli isolated from female RTI and neonatal sepses possess unique properties that may enhance their virulence. These properties are similar to those associated with other E. coli extra-intestinal infections, indicating that strategies such as vaccination or bacterial interference that may be developed against urinary tract infections (UTI) and other E. coli extra-intestinal infections may also prevent selected female RTI.

Invasive Escherichia coli infection in infancy: clinical manifestation, outcome, and antimicrobial susceptibility.

Huang YS, Wang SM, Liu CC, Yang YJ.

Department of Pediatrics, National Cheng Kung University Hospital, Tainan, Taiwan, ROC.
J Microbiol Immunol Infect 2002 Jun;35(2):103-8 Abstract quote
Escherichia coli is the second most common bacterium isolated from the blood of neonates with sepsis. During a 12-year period from January 1988 through December 2000, E. coli sepsis or central nervous system infections were diagnosed in a total of 46 infants (M/F ratio, 3.6:1) in a tertiary care medical center.

These infants were stratified into 3 groups according to age at disease onset. Group A include infants at birth to 7 days old; Group B, 7 days to 1 month old; and Group C, beyond 1 month old. Among them, 13 had sepsis, 24 had urosepsis, and 9 had meningitis or meningoencephalitis. All patients with central nervous system infections were younger than 40 days old. In the urosepsis group, 22 (91.7%) of 24 patients were younger than 6 months old with a male predominance (M/F ratio, 20:4), and 7 (29.2%) of 24 had urinary tract anomaly. Nine (68%) of 13 patients with sepsis had underlying disease. The most common clinical signs and symptoms were fever (89.1%), followed by tachycardia (71.7%), ill looking (50%), poor feeding (30.4%), and tachypnea (23.9%). The significant laboratory findings were elevated C-reactive protein (60.9%), and leukocytosis (56.5%) with left shifting (43.5%). Antimicrobial susceptibility test of the isolates showed a 67.7% resistant rate to ampicillin and a 35.5% resistant rate to chloramphenicol between 1994 and 2000. No significant increase in the resistance rate of the strains was noted compared with results from 2 studies conducted at different periods of time (1988-1993 and 1994-2000). Two infants with central nervous system infection died and 5 experienced major neurological sequelae.

The clinical spectrum of invasive E. coli infections is age-related and associated with the underlying conditions. The prognosis was related to the development of central nervous system complications.

SPONTANEOUS BACTERIAL PERITONITIS

Spontaneous bacterial peritonitis (SBP): clinical, laboratory, and prognostic features. A single-center experience.
Thanopoulou AC, Koskinas JS, Hadziyannis SJ.

Academic Department of Medicine, Hippokration General Hospital, 114 Vas. Sophia's Street, 115 27, Athens, Greece
Eur J Intern Med 2002 May;13(3):194-198 Abstract quote
BACKGROUND: The aim of the present study was to assess the clinical and laboratory characteristics, the course, and the factors influencing the hospital mortality and relapse rate of spontaneous bacterial peritonitis (SBP) in cirrhotic patients admitted in a single University Hospital in Greece.

METHODS: The study comprises the evaluation of 81 cirrhotic patients who developed SBP during a 30-month period.

RESULTS: The occurrence of SBP was independent of the etiology of liver disease and was symptomatic in 66/81 patients (82%). Encephalopathy, as presenting symptom, occurred mainly in Child C patients. Ascitic fluid culture was positive in 20 patients (25%); E. coli (60%) and Enterococcus faecalis (14%) were the most common bacteria isolated. Empirical treatment was effective in 94% of patients. Renal impairment was observed in 21 patients (26%), six of whom developed hepatorenal syndrome. Total mortality was 10% and was related to the existence of symptoms (P<0.01), ascetic fluid polymorphonuclear cell count (P<0.05), bilirubin levels (P<0.01), and kidney function at the beginning of the episode (P<0.01). The relapse rate was 24.6% and was related to the Child stage (P<0.01).

CONCLUSIONS: SBP was asymptomatic in a substantial number of patients. Deterioration of renal function was frequently observed and was the main cause of death. The low (10%) in-hospital mortality seems to be related to earlier diagnosis and treatment. Relapse was associated with the severity of liver disease.

URINARY TRACT

Roles of host and bacterial virulence factors in the development of upper urinary tract infection caused by Escherichia coli.

Tseng CC, Wu JJ, Liu HL, Sung JM, Huang JJ.

Division of Nephrology, Department of Internal Medicine, National Cheng Kung University Hospital, Tainan, Taiwan, Republic of China.

Am J Kidney Dis 2002 Apr;39(4):744-52 Abstract quote
Aims of this study are to identify host and Escherichia coli virulence factors associated with upper urinary tract infection (UTI) by comparing them with those for lower UTI and determining the association between major predisposing host factors for upper UTI and urovirulence genes for E coli.

Host factors and urovirulence genes of E coli associated with bacteremia in patients with upper UTI and their interactions also were studied. One hundred thirty-nine adult patients who fulfilled clinical diagnostic criteria for upper (n = 81) or lower UTI (n = 58) caused by E coli between January 1997 and December 1999 were retrospectively enrolled into this study. Old age (> or =60 years), male sex, diabetes with poor blood glucose control (ie, glycosylated hemoglobin A1C > or = 8.1%), immunosuppression, and urinary tract obstruction were more frequently associated host factors for patients with upper UTI than for those with lower UTI. Using polymerase chain reaction, the papG class II allele was detected more frequently for E coli strains isolated from patients with upper UTI than for those from patients with lower UTI (85% versus 52%; P < 0.0001).

Multivariate analysis showed that diabetes with poor blood glucose control, immunosuppression, urinary tract obstruction, and papG class II allele were independently associated with upper UTI. For patients without these three predisposing host factors, the prevalence of papG class II allele was significantly greater in those with upper UTI than those with lower UTI. However, the papG class II allele was less prevalent in strains isolated from patients with upper UTI with urinary tract obstruction or with two of the three predisposing host factors. In addition, both univariate and multivariate analyses showed that old age and papG class II allele were risk factors for the development of E coli bacteremia in patients with upper UTI. In conclusion, both host and E coli virulence factors contribute to the development of upper UTI, and less virulent strains can cause upper UTI in hosts with predisposing factors.

HISTOLOGICAL TYPES CHARACTERIZATION

GENERAL

VARIANTS

SPECIAL STAINS/IMMUNOPEROXIDASE/
OTHER CHARACTERIZATION

SPECIAL STAINS

IMMUNOPEROXIDASE

DIFFERENTIAL DIAGNOSIS KEY DIFFERENTIATING FEATURES

PROGNOSIS AND TREATMENT CHARACTERIZATION

PROGNOSTIC FACTORS

HEMOLYTIC UREMIC SYNDROME

Risk of hemolytic uremic syndrome after antibiotic treatment of Escherichia coli O157:H7 enteritis: a meta-analysis.

Safdar N, Said A, Gangnon RE, Maki DG.

Department of Medicine, University of Wisconsin Medical School and University of Wisconsin Hospital and Clinics, Madison, WI 53792-5158, USA.
JAMA 2002 Aug 28;288(8):996-1001 Abstract quote
CONTEXT: The use of antibiotics for treatment of Escherichia coli O157:H7 infection has become controversial since a recent small study found that it may increase the risk of hemolytic uremic syndrome (HUS). However, other larger studies have reported a protective effect or no association.

OBJECTIVE: To determine whether antibiotic therapy for E coli O157:H7 enteritis increases the risk of HUS.

DATA SOURCES: PubMed and MEDLINE computer searches were performed for studies published from January 1983 to February 2001 using the key words hemolytic uremic syndrome, risk factor, antibiotics, and Escherichia coli O157:H7. Reference lists of relevant publications were reviewed, and 12 experts in the field were contacted to identify additional reports. No language restrictions were applied to the search.

STUDY SELECTION: Studies were included if they reported a series of patients with documented E coli O157:H7 enteritis, some of whom developed HUS; had clear definitions of HUS; and had adequate data delineating the relationship between antibiotic therapy and the occurrence of HUS. Nine of the 26 identified studies fulfilled these criteria.

DATA EXTRACTION: Two authors (N.S. and A.S.) independently reviewed each report identified by the searches and recorded predetermined information relevant to the inclusion criteria. A pooled odds ratio was calculated using a fixed-effects model, with assessment of heterogeneity among the studies.

DATA SYNTHESIS: The pooled odds ratio was 1.15 (95% confidence interval, 0.79-1.68), indicating that there does not appear to be an increased risk of HUS with antibiotic treatment of E coli O157:H7 enteritis. Incomplete reporting of data in individual studies precluded adjustment for severity of illness.

CONCLUSION: Our meta-analysis did not show a higher risk of HUS associated with antibiotic administration. A randomized trial of adequate power, with multiple distinct strains of E coli O157:H7 represented, is needed to conclusively determine whether antibiotic treatment of E coli O157:H7 enteritis increases the risk of HUS.

TREATMENT

ANTBIOTICS

Antibiotic use and Escherichia coli resistance trends for quinolones and cotrimoxazole in Sweden.

Farra A, Skoog G, Wallen L, Kahlmeter G, Kronvall G, Sorberg M; Swebact Study Group.

Infectious Disease Section, Karolinska Hospital, Stockholm, Sweden
Scand J Infect Dis 2002;34(6):449-55 Abstract quote
Resistance rates among Escherichia coli isolates for quinolones and cotrimoxazole were analysed at 12 Swedish hospitals, and compared with antibiotic use. Resistance figures for E. coli were retrieved from the diagnostic microbiology service databases for the period 1989-99, and antibiotic sales figures were obtained from the National Corporation of Swedish Pharmacies.

At the 2 university teaching hospitals included, norfloxacin resistance of E. coli increased significantly (p < 0.001) from 0% to 2.7% and 2.5%, respectively. Ciprofloxacin resistance increased (p < 0.001) in parallel. Quinolone use increased until 1992; subsequently, sales have remained at a stable level. The increase in norfloxacin and ciprofloxacin resistance started relatively simultaneously in all hospitals, around 1991. Cotrimoxazole resistance has also been increasing significantly in most hospitals, in spite of decreasing sales of cotrimoxazole and trimethoprim. Similar trends could be seen in blood isolates from the same hospitals for the period 1991-98.

Clinical laboratory data are subject to bias but surveillance over longer periods of time provides a useful method for detecting trends in increasing resistance and therefore functions as a resistance warning system.

Henry JB. Clinical Diagnosis and Management by Laboratory Methods. Twentieth Edition. WB Saunders. 2001.
Rosai J. Ackerman's Surgical Pathology. Eight Edition. Mosby 1996.
Sternberg S. Diagnostic Surgical Pathology. Third Edition. Lipincott Williams and Wilkins 1999.
Weedon D. Weedon's Skin Pathology. Second Edition. Churchill Livingstone. 2002.
Fitzpatrick's Dermatology in General Medicine. 5th Edition. McGraw-Hill. 1999.
Robbins Pathologic Basis of Disease. Sixth Edition. WB Saunders 1999.

Commonly Used Terms

Bacteria

Last Updated 9/12/2002

GROSS APPEARANCE/ CLINICAL VARIANTS	CHARACTERIZATION
GENERAL
VARIANTS
INFANCY
Virulence factors of Escherichia coli isolated from female reproductive tract infections and neonatal sepsis. Cook SW, Hammill HA, Hull RA. Department of Biology, Houston Baptist University, TX, USA.	Infect Dis Obstet Gynecol 2001;9(4):203-7 Abstract quote OBJECTIVE: The presence of enterobacteria such as Escherichia coli in the vagina of normal women is not synonymous with infection. However, vaginal E. coli may also cause symptomatic infections. We examined bacterial virulence properties that may promote symptomatic female reproductive tract infections (RTI) and neonatal sepsis. METHODS: E. coli isolated as the causative agent from cases of vaginitis (n = 50), tubo-ovarian abscess (n = 45) and neonatal sepsis (n = 45) was examined for selected phenotypic and genetic virulence properties. Results were compared with the frequency of the same properties among fecal E. coli not associated with disease. RESULTS: A significantly greater proportion of infection E. coli exhibited D-mannose resistant hemagglutination compared with fecal E. coli (p < 0.01). This adherence phenotype was associated with the presence of P fimbriae (pap) genes which were also significantly more prevalent among isolates from all three infection sites (p < 0.01). The majority of pap+ isolates contained the papG3 allele (Class II) regardless of infection type. Increased frequency of Type IC genes among vaginitis and abscess isolates was also noted. No significant differences in frequency of other bacterial adherence genes, fim, sfa, uca (gaf or dra were observed. E. coli associated with vaginitis was significantly more likely to be hemolytic (Hly+) than were fecal isolates (p < 0.05). The Hly+ phenotype was also more prevalent among tubo-ovarian abscess and neonatal sepsis isolates (p < 0.08). CONCLUSIONS: E. coli isolated from female RTI and neonatal sepses possess unique properties that may enhance their virulence. These properties are similar to those associated with other E. coli extra-intestinal infections, indicating that strategies such as vaccination or bacterial interference that may be developed against urinary tract infections (UTI) and other E. coli extra-intestinal infections may also prevent selected female RTI.
Invasive Escherichia coli infection in infancy: clinical manifestation, outcome, and antimicrobial susceptibility. Huang YS, Wang SM, Liu CC, Yang YJ. Department of Pediatrics, National Cheng Kung University Hospital, Tainan, Taiwan, ROC.	J Microbiol Immunol Infect 2002 Jun;35(2):103-8 Abstract quote Escherichia coli is the second most common bacterium isolated from the blood of neonates with sepsis. During a 12-year period from January 1988 through December 2000, E. coli sepsis or central nervous system infections were diagnosed in a total of 46 infants (M/F ratio, 3.6:1) in a tertiary care medical center. These infants were stratified into 3 groups according to age at disease onset. Group A include infants at birth to 7 days old; Group B, 7 days to 1 month old; and Group C, beyond 1 month old. Among them, 13 had sepsis, 24 had urosepsis, and 9 had meningitis or meningoencephalitis. All patients with central nervous system infections were younger than 40 days old. In the urosepsis group, 22 (91.7%) of 24 patients were younger than 6 months old with a male predominance (M/F ratio, 20:4), and 7 (29.2%) of 24 had urinary tract anomaly. Nine (68%) of 13 patients with sepsis had underlying disease. The most common clinical signs and symptoms were fever (89.1%), followed by tachycardia (71.7%), ill looking (50%), poor feeding (30.4%), and tachypnea (23.9%). The significant laboratory findings were elevated C-reactive protein (60.9%), and leukocytosis (56.5%) with left shifting (43.5%). Antimicrobial susceptibility test of the isolates showed a 67.7% resistant rate to ampicillin and a 35.5% resistant rate to chloramphenicol between 1994 and 2000. No significant increase in the resistance rate of the strains was noted compared with results from 2 studies conducted at different periods of time (1988-1993 and 1994-2000). Two infants with central nervous system infection died and 5 experienced major neurological sequelae. The clinical spectrum of invasive E. coli infections is age-related and associated with the underlying conditions. The prognosis was related to the development of central nervous system complications.
SPONTANEOUS BACTERIAL PERITONITIS
Spontaneous bacterial peritonitis (SBP): clinical, laboratory, and prognostic features. A single-center experience. Thanopoulou AC, Koskinas JS, Hadziyannis SJ. Academic Department of Medicine, Hippokration General Hospital, 114 Vas. Sophia's Street, 115 27, Athens, Greece	Eur J Intern Med 2002 May;13(3):194-198 Abstract quote BACKGROUND: The aim of the present study was to assess the clinical and laboratory characteristics, the course, and the factors influencing the hospital mortality and relapse rate of spontaneous bacterial peritonitis (SBP) in cirrhotic patients admitted in a single University Hospital in Greece. METHODS: The study comprises the evaluation of 81 cirrhotic patients who developed SBP during a 30-month period. RESULTS: The occurrence of SBP was independent of the etiology of liver disease and was symptomatic in 66/81 patients (82%). Encephalopathy, as presenting symptom, occurred mainly in Child C patients. Ascitic fluid culture was positive in 20 patients (25%); E. coli (60%) and Enterococcus faecalis (14%) were the most common bacteria isolated. Empirical treatment was effective in 94% of patients. Renal impairment was observed in 21 patients (26%), six of whom developed hepatorenal syndrome. Total mortality was 10% and was related to the existence of symptoms (P<0.01), ascetic fluid polymorphonuclear cell count (P<0.05), bilirubin levels (P<0.01), and kidney function at the beginning of the episode (P<0.01). The relapse rate was 24.6% and was related to the Child stage (P<0.01). CONCLUSIONS: SBP was asymptomatic in a substantial number of patients. Deterioration of renal function was frequently observed and was the main cause of death. The low (10%) in-hospital mortality seems to be related to earlier diagnosis and treatment. Relapse was associated with the severity of liver disease.
URINARY TRACT
Roles of host and bacterial virulence factors in the development of upper urinary tract infection caused by Escherichia coli. Tseng CC, Wu JJ, Liu HL, Sung JM, Huang JJ. Division of Nephrology, Department of Internal Medicine, National Cheng Kung University Hospital, Tainan, Taiwan, Republic of China.	Am J Kidney Dis 2002 Apr;39(4):744-52 Abstract quote Aims of this study are to identify host and Escherichia coli virulence factors associated with upper urinary tract infection (UTI) by comparing them with those for lower UTI and determining the association between major predisposing host factors for upper UTI and urovirulence genes for E coli. Host factors and urovirulence genes of E coli associated with bacteremia in patients with upper UTI and their interactions also were studied. One hundred thirty-nine adult patients who fulfilled clinical diagnostic criteria for upper (n = 81) or lower UTI (n = 58) caused by E coli between January 1997 and December 1999 were retrospectively enrolled into this study. Old age (> or =60 years), male sex, diabetes with poor blood glucose control (ie, glycosylated hemoglobin A1C > or = 8.1%), immunosuppression, and urinary tract obstruction were more frequently associated host factors for patients with upper UTI than for those with lower UTI. Using polymerase chain reaction, the papG class II allele was detected more frequently for E coli strains isolated from patients with upper UTI than for those from patients with lower UTI (85% versus 52%; P < 0.0001). Multivariate analysis showed that diabetes with poor blood glucose control, immunosuppression, urinary tract obstruction, and papG class II allele were independently associated with upper UTI. For patients without these three predisposing host factors, the prevalence of papG class II allele was significantly greater in those with upper UTI than those with lower UTI. However, the papG class II allele was less prevalent in strains isolated from patients with upper UTI with urinary tract obstruction or with two of the three predisposing host factors. In addition, both univariate and multivariate analyses showed that old age and papG class II allele were risk factors for the development of E coli bacteremia in patients with upper UTI. In conclusion, both host and E coli virulence factors contribute to the development of upper UTI, and less virulent strains can cause upper UTI in hosts with predisposing factors.

Epidemiology
Disease Associations
Pathogenesis
Laboratory/Radiologic/Other Diagnostic Testing
Gross Appearance and Clinical Variants
Histopathological Features and Variants
Special Stains/Immunohistochemistry/Electron Microscopy
Differential Diagnosis
Prognosis and Treatment
Commonly Used Terms

EPIDEMIOLOGY	CHARACTERIZATION
SYNONYMS
INCIDENCE
AGE RANGE-MEDIAN
SEX (M:F)
GEOGRAPHY

DISEASE ASSOCIATIONS	CHARACTERIZATION
HEMOLYTIC UREMIC SYNDROME

LABORATORY/RADIOLOGIC/ OTHER TESTS	CHARACTERIZATION
RADIOLOGIC
LABORATORY MARKERS
PCR
Comparison of DNA hybridization and PCR assays for detection of putative pathogenic enteroadherent Escherichia coli. Scaletsky IC, Fabbricotti SH, Aranda KR, Morais MB, Fagundes-Neto U. Department of Microbiology, Immunology, and Parasitology, Universidade Federal de Sao Paulo, Escola Paulista de Medicina, Sao Paulo, SP, Brazil CEP 04023-062.	J Clin Microbiol 2002 Apr;40(4):1254-8 Abstract quote The correlation of the different adherence patterns with DNA probes and PCR primers for the identification of Escherichia coli was analyzed in isolates from children, less than 2 years of age with or without diarrhea, from different regions of Brazil. A total of 1,428 isolates obtained from 338 patients and 322 control children were studied. The enteropathogenic E. coli (EPEC) adherence factor (EAF) probe was shown to be as good as the HEp-2 adhesion assay for the detection of typical EPEC strains. The DNA probes used to detect diffusely adhering E. coli and enteroaggregative E. coli (EAEC) showed low sensitivities (64 and 50%, respectively), and the best method of identifying these organisms in clinical research remains the HEp-2 adherence assay. The "bundle-forming pilus" (BFP) and the EAEC PCR assays could be used instead of the DNA probes as a screening method for typical EPEC and EAEC carrying the EAEC probe sequence in the clinical laboratory. In our study, only typical EPEC strains that carried EAF and BFP were associated with acute diarrhea.

HISTOLOGICAL TYPES	CHARACTERIZATION
GENERAL
VARIANTS

SPECIAL STAINS/IMMUNOPEROXIDASE/ OTHER	CHARACTERIZATION
SPECIAL STAINS
IMMUNOPEROXIDASE

PROGNOSIS AND TREATMENT	CHARACTERIZATION
PROGNOSTIC FACTORS
HEMOLYTIC UREMIC SYNDROME
Risk of hemolytic uremic syndrome after antibiotic treatment of Escherichia coli O157:H7 enteritis: a meta-analysis. Safdar N, Said A, Gangnon RE, Maki DG. Department of Medicine, University of Wisconsin Medical School and University of Wisconsin Hospital and Clinics, Madison, WI 53792-5158, USA.	JAMA 2002 Aug 28;288(8):996-1001 Abstract quote CONTEXT: The use of antibiotics for treatment of Escherichia coli O157:H7 infection has become controversial since a recent small study found that it may increase the risk of hemolytic uremic syndrome (HUS). However, other larger studies have reported a protective effect or no association. OBJECTIVE: To determine whether antibiotic therapy for E coli O157:H7 enteritis increases the risk of HUS. DATA SOURCES: PubMed and MEDLINE computer searches were performed for studies published from January 1983 to February 2001 using the key words hemolytic uremic syndrome, risk factor, antibiotics, and Escherichia coli O157:H7. Reference lists of relevant publications were reviewed, and 12 experts in the field were contacted to identify additional reports. No language restrictions were applied to the search. STUDY SELECTION: Studies were included if they reported a series of patients with documented E coli O157:H7 enteritis, some of whom developed HUS; had clear definitions of HUS; and had adequate data delineating the relationship between antibiotic therapy and the occurrence of HUS. Nine of the 26 identified studies fulfilled these criteria. DATA EXTRACTION: Two authors (N.S. and A.S.) independently reviewed each report identified by the searches and recorded predetermined information relevant to the inclusion criteria. A pooled odds ratio was calculated using a fixed-effects model, with assessment of heterogeneity among the studies. DATA SYNTHESIS: The pooled odds ratio was 1.15 (95% confidence interval, 0.79-1.68), indicating that there does not appear to be an increased risk of HUS with antibiotic treatment of E coli O157:H7 enteritis. Incomplete reporting of data in individual studies precluded adjustment for severity of illness. CONCLUSION: Our meta-analysis did not show a higher risk of HUS associated with antibiotic administration. A randomized trial of adequate power, with multiple distinct strains of E coli O157:H7 represented, is needed to conclusively determine whether antibiotic treatment of E coli O157:H7 enteritis increases the risk of HUS.
TREATMENT
ANTBIOTICS
Antibiotic use and Escherichia coli resistance trends for quinolones and cotrimoxazole in Sweden. Farra A, Skoog G, Wallen L, Kahlmeter G, Kronvall G, Sorberg M; Swebact Study Group. Infectious Disease Section, Karolinska Hospital, Stockholm, Sweden	Scand J Infect Dis 2002;34(6):449-55 Abstract quote Resistance rates among Escherichia coli isolates for quinolones and cotrimoxazole were analysed at 12 Swedish hospitals, and compared with antibiotic use. Resistance figures for E. coli were retrieved from the diagnostic microbiology service databases for the period 1989-99, and antibiotic sales figures were obtained from the National Corporation of Swedish Pharmacies. At the 2 university teaching hospitals included, norfloxacin resistance of E. coli increased significantly (p < 0.001) from 0% to 2.7% and 2.5%, respectively. Ciprofloxacin resistance increased (p < 0.001) in parallel. Quinolone use increased until 1992; subsequently, sales have remained at a stable level. The increase in norfloxacin and ciprofloxacin resistance started relatively simultaneously in all hospitals, around 1991. Cotrimoxazole resistance has also been increasing significantly in most hospitals, in spite of decreasing sales of cotrimoxazole and trimethoprim. Similar trends could be seen in blood isolates from the same hospitals for the period 1991-98. Clinical laboratory data are subject to bias but surveillance over longer periods of time provides a useful method for detecting trends in increasing resistance and therefore functions as a resistance warning system.