
Full text loading...
Category: Clinical Microbiology
Escherichia, Shigella, and Salmonella, Page 1 of 2
< Previous page | Next page > /docserver/preview/fulltext/10.1128/9781555816728/9781555814632_Chap35-1.gif /docserver/preview/fulltext/10.1128/9781555816728/9781555814632_Chap35-2.gifAbstract:
Members of the genus Shigella are phenotypically similar to Escherichia coli and, with the exception of Shigella boydii serotype 13, would be considered the same species by DNA-DNA hybridization analysis and whole-genome sequence analysis. The dynamic nature of the Shiga toxin-converting phages has implications for diagnostic testing for Shiga toxin-producing E. coli (STEC). Since STEC strains can lose critical virulence genes, some researchers have proposed that multiple virulence-associated genes, as well as conserved genes, be used to diagnose infections by these bacteria. This concept would also apply to other pathotypes of E. coli, as most of them carry critical virulence genes on mobile genetic elements. A preliminary report can be issued as soon as a presumptive identification of Salmonella is obtained. In most situations, a presumptive identification is based on phenotypic traits determined by either traditional or commercial systems or by reactivity with Salmonella O grouping antisera. A confirmed identification requires both phenotypic identification and O group or serotype determination. As national surveillance systems depend on the receipt of serotype information for Salmonella strains isolated in the United States, laboratories should follow the procedures recommended by their state health departments for submitting Salmonella isolates for further characterization, including complete serotyping. The antimicrobial susceptibilities of typhoidal Salmonella strains and strains from normally sterile sites should be determined, and the strains should be forwarded to a reference or public health laboratory for complete phenotypic identification and serotyping.
Full text loading...
Biochemical reactions of the six species of Escherichia and selected members of the family Enterobacteriaceae a
a Values are percentages of isolates tested with positive test results within 1 or 2 days of incubation at 35 to 37°C. Reactions for isolates that become positive after 2 days are not considered. Data were compiled from findings published by Ewing et al. ( 68 ), Wathen-Grady et al. ( 208 , 209 ), Ansaruzzaman et al. ( 8 ), Pryamukhina and Khomenko ( 163 ), and Farmer ( 71 ) and from unpublished findings from the reference laboratory at the CDC (1972 to 2005).
b Excludes strains previously identified as S. boydii 13.
Biochemical reactions of the six species of Escherichia and selected members of the family Enterobacteriaceae a
a Values are percentages of isolates tested with positive test results within 1 or 2 days of incubation at 35 to 37°C. Reactions for isolates that become positive after 2 days are not considered. Data were compiled from findings published by Ewing et al. ( 68 ), Wathen-Grady et al. ( 208 , 209 ), Ansaruzzaman et al. ( 8 ), Pryamukhina and Khomenko ( 163 ), and Farmer ( 71 ) and from unpublished findings from the reference laboratory at the CDC (1972 to 2005).
b Excludes strains previously identified as S. boydii 13.
Frequently encountered serotypes of diarrheagenic E. coli a
a Outbreak-related serotypes are shown in bold. NM, nonmotile; NT, not typeable.
Frequently encountered serotypes of diarrheagenic E. coli a
a Outbreak-related serotypes are shown in bold. NM, nonmotile; NT, not typeable.
Partial listing of commercial suppliers of reagents for detection of STECa
a This table is not intended to be a comprehensive listing. The FDA has not approved all of these reagents for use with clinical specimens. This table does not include reagents or tests specifically intended for examination of food, water, or environmental specimens. The online version of the Bacteriological Analytical Manual lists many tests for food specimens (http://www.fda.gov). Inclusion does not constitute endorsement by the CDC or ASM.
Partial listing of commercial suppliers of reagents for detection of STECa
a This table is not intended to be a comprehensive listing. The FDA has not approved all of these reagents for use with clinical specimens. This table does not include reagents or tests specifically intended for examination of food, water, or environmental specimens. The online version of the Bacteriological Analytical Manual lists many tests for food specimens (http://www.fda.gov). Inclusion does not constitute endorsement by the CDC or ASM.
Differentiation of E. coli and Shigella
a Abbreviations: +, 90% or more positive within or 2 days; –, no reaction (90% or more) in 7 days; d, different reactions [+, (+), +]. Adapted from Ewing ( 66 ).
b Nonmotile, anaerogenic biotypes sometimes referred to as Alkalescens-Dispar bioserotypes.
Differentiation of E. coli and Shigella
a Abbreviations: +, 90% or more positive within or 2 days; –, no reaction (90% or more) in 7 days; d, different reactions [+, (+), +]. Adapted from Ewing ( 66 ).
b Nonmotile, anaerogenic biotypes sometimes referred to as Alkalescens-Dispar bioserotypes.
Phenotypic reactions useful for differentiating Salmonella species and subspecies a
a Reactions after incubation at 37°C. +, 90% (or more) of stains were positive within 1 or 2 days; (+), positive reaction after 3 or more days; –, no reaction (90% or more) in 7 days; d, different reactions [+, (+), –]; KCN, potassium cyanide; ONPG, o-nitrophenyl-β-D-galactopyranoside. (Adapted from reference 66 with permission of the publisher.)
b A total of 67% were positive.
c A total of 15% were positive.
d A total of 85% were positive.
e A total of 22% were positive.
f A total of 15% were positive.
g A total of 44% were positive.
h A total of 60% were positive.
i A total of 30% were positive.
j Sodium potassium tartrate ( 66 ).
Phenotypic reactions useful for differentiating Salmonella species and subspecies a
a Reactions after incubation at 37°C. +, 90% (or more) of stains were positive within 1 or 2 days; (+), positive reaction after 3 or more days; –, no reaction (90% or more) in 7 days; d, different reactions [+, (+), –]; KCN, potassium cyanide; ONPG, o-nitrophenyl-β-D-galactopyranoside. (Adapted from reference 66 with permission of the publisher.)
b A total of 67% were positive.
c A total of 15% were positive.
d A total of 85% were positive.
e A total of 22% were positive.
f A total of 15% were positive.
g A total of 44% were positive.
h A total of 60% were positive.
i A total of 30% were positive.
j Sodium potassium tartrate ( 66 ).