Usability and Performance of CHROMagar STEC Medium in Detection of Shiga Toxin-Producing Escherichia coli Strains

Hirvonen, Jari J.; Siitonen, Anja; Kaukoranta, Suvi-Sirkku

doi:10.1128/jcm.01754-12

Cited by 74 publications

(59 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Furthermore, due to easier identification of suspicious colonies, the CHROMagar STEC medium proved to be an effective supplemental medium for isolation, especially of more virulent (LEE-positive) STEC serotypes, as described previously by others (46)(47)(48). The medium also supported the growth of EAEC (O104: H4) and EPEC (O88:H25 and ONT:H31), suggesting that it could also be a useful tool for the support of EAEC and EPEC isolation, as described previously (49).…”

Section: Discussionmentioning

confidence: 99%

Assessing the Public Health Risk of Shiga Toxin-Producing Escherichia coli by Use of a Rapid Diagnostic Screening Algorithm

et al. 2015

View full text Add to dashboard Cite

dShiga toxin-producing Escherichia coli (STEC) is an enteropathogen of public health concern because of its ability to cause serious illness and outbreaks. In this prospective study, a diagnostic screening algorithm to categorize STEC infections into risk groups was evaluated. The algorithm consists of prescreening stool specimens with real-time PCR (qPCR) for the presence of stx genes. The qPCR-positive stool samples were cultured in enrichment broth and again screened for stx genes and additional virulence factors (escV, aggR, aat, bfpA) and O serogroups (O26, O103, O104, O111, O121, O145, O157). Also, PCR-guided culture was performed with sorbitol MacConkey agar (SMAC) and CHROMagar STEC medium. The presence of virulence factors and O serogroups was used for presumptive pathotype (PT) categorization in four PT groups. The potential risk for severe disease was categorized from high risk for PT group I to low risk for PT group III, whereas PT group IV consists of unconfirmed stx qPCRpositive samples. In total, 5,022 stool samples of patients with gastrointestinal symptoms were included. The qPCR detected stx genes in 1.8% of samples. Extensive screening for virulence factors and O serogroups was performed on 73 samples. After enrichment, the presence of stx genes was confirmed in 65 samples (89%). By culture on selective media, STEC was isolated in 36% (26/73 samples). Threshold cycle (C T ) values for stx genes were significantly lower after enrichment compared to direct qPCR (P < 0.001). In total, 11 (15%), 19 (26%), 35 (48%), and 8 (11%) samples were categorized into PT groups I, II, III, and IV, respectively. Several virulence factors (stx 2 , stx 2a , stx 2f , toxB, eae, efa1, cif, espA, tccP, espP, nleA and/or nleB, tir cluster) were associated with PT groups I and II, while others (stx 1 , eaaA, mch cluster, ireA) were associated with PT group III. Furthermore, the number of virulence factors differed between PT groups (analysis of variance, P < 0.0001). In conclusion, a diagnostic algorithm enables fast discrimination of STEC infections associated with a high to moderate risk for severe disease (PT groups I and II) from less-virulent STEC (PT group III). Shiga toxin-producing Escherichia coli (STEC) is a zoonotic pathogen frequently identified as causative agent of acute diarrheal disease in humans. The outcomes of STEC infections may range from asymptomatic carriage and mild diarrhea to severe disease, such as hemorrhagic colitis (HC) and hemolytic-uremic syndrome (HUS) (1-3).Based on pathogenic properties, a subgroup of STEC is also designated enterohemorrhagic E. coli (EHEC); this subgroup of stx-positive strains also contains the locus of enterocyte effacement (LEE) pathogenicity island (4). EHEC belongs to certain serotypes that are frequently associated with outbreaks and lifethreatening illnesses (5). Worldwide, the most common EHEC serotype both in outbreaks and in sporadic cases of severe disease is E. coli O157:H7 (4, 6, 7). Consequently, public health and regulatory responses have been focuse...

show abstract

Section: Discussionmentioning

confidence: 99%

Assessing the Public Health Risk of Shiga Toxin-Producing Escherichia coli by Use of a Rapid Diagnostic Screening Algorithm

et al. 2015

View full text Add to dashboard Cite

show abstract

“…In combination with selective substrates, chromogenic culture can be used for the isolation of certain groups of microbes (1) or even for one particular pathogen (4). These media have been shown to improve the culturebased methodology by decreasing the total turnaround time and by increasing the differentiation and detection of the target microbes of interest (2,4,5).…”

mentioning

confidence: 99%

Performance of Sa Select , a Chromogenic Medium for Detection of Staphylococci in Clinical Specimens

Hirvonen¹,

Kerttula²,

Kaukoranta³

2014

J Clin Microbiol

Self Cite

View full text Add to dashboard Cite

bIn a preliminary study, known staphylococcus (n ‫؍‬ 86) and other microbial (n ‫؍‬ 12) isolates were plated on three chromogenic media, SaSelect (Bio-Rad, Hercules, CA, USA), CHROMagar Staph. aureus (CHROMagar Microbiology, Paris, France), and S. aureus ID (bioMérieux, Marcy l'Etoile, France). The sensitivities of all the media to detect Staphylococcus aureus after 24 h of incubation were high (100.0%). However, their specificities varied at 93.3% (95% confidence interval [CI], 86.0% to 100.0%) (CHROMagar Staph. aureus), 97.8% (95% CI, 93.5% to 100.0%) (S. aureus ID), and 100.0% (SaSelect). SaSelect also showed the highest sensitivity for recovery and differentiation of other staphylococci. As the best performing chromogenic medium, SaSelect was then prospectively compared to conventional culture and identification tests for the detection of staphylococci from 2,780 clinical specimens. A total of 1,589 staphylococcal isolates were recovered. Of these, 912 were S. aureus and 677 were other staphylococci. The sensitivity and specificity of SaSelect to detect S. aureus in clinical specimens after 24 h of incubation were 99.6% and 99.9% (95% CI, 99.2% to 100.0% and 99.8% to 100.0%), respectively, whereas the sensitivity and specificity using conventional plates combined with laboratory identification methods were 96.8% and 99.5% (95% CI, 95.7 to 97.9% and 99.2% to 99.8%). For the recovery and preliminary identification of other staphylococci, the sensitivity and specificity of SaSelect were 94.4% and 99.9%. SaSelect is a well-performing chromogenic medium that significantly improved the detection of staphylococci, especially S. aureus, compared to conventional culture (P < 0.0001).

show abstract

“…The development of a universal medium for STEC is difficult for many reasons, including the low STEC density and potential inhibitors in stool specimens and the absence of culture characteristics common to all the various unrelated E. coli lineages that have acquired stx-harboring bacteriophages (18). Recently, new chromogenic media not based on sorbitol fermentation were developed to improve the detection of O157 (19) or the most prevalent EHEC serogroups (20,21). CHROMagar STEC medium (CHROMagar Microbiology, Paris, France) allows the growth and presumptive identification (mauve colonies) of Ϸ75% of STEC isolates in a vast collection of isolates encompassing 20 to 40 dif-…”

mentioning

confidence: 99%

“…CHROMagar STEC medium (CHROMagar Microbiology, Paris, France) allows the growth and presumptive identification (mauve colonies) of Ϸ75% of STEC isolates in a vast collection of isolates encompassing 20 to 40 dif-ferent serotypes, including the most common serotypes of EHEC (20,21). This chromogenic medium has also been evaluated for use with stools, but on a very limited scale (47 stool specimens), such that definitive conclusions about the suitability of this medium could not be drawn (20).…”

mentioning

confidence: 99%

Evaluation of CHROMagar STEC and STEC O104 Chromogenic Agar Media for Detection of Shiga Toxin-Producing Escherichia coli in Stool Specimens

et al. 2013

View full text Add to dashboard Cite

The performance of CHROMagar STEC and CHROMagar STEC O104 (CHROMagar Microbiology, Paris, France) media for the detection of Shiga toxin-producing Escherichia coli (STEC) was assessed with 329 stool specimens collected over 14 months from patients with suspected STEC infections (June 2011 to August 2012). The CHROMagar STEC medium, after an enrichment broth step, allowed the recovery of the STEC strain from 32 of the 39 (82.1%) Shiga toxin-positive stool specimens, whereas the standard procedure involving Drigalski agar allowed the recovery of only three additional STEC strains. The isolates that grew on CHROMagar STEC medium belonged to 15 serotypes, including the prevalent non-sorbitol-fermenting (NSF) O157:H7, O26: H11, and O104:H4 serotypes. The sensitivity, specificity, and positive and negative predictive values for the CHROMagar STEC medium were between 89.1% and 91.4%, 83.7% and 86.7%, 40% and 51.3%, and 98% and 98.8%, respectively, depending on whether or not stx-negative eae-positive E. coli was considered atypical enteropathogenic E. coli (EPEC) or STEC that had lost Shiga toxin genes during infection. In conclusion, the good performance of CHROMagar STEC agar medium, in particular, the high negative predictive value, and its capacity to identify NSF O157:H7 as well as common non-O157 STEC may be useful for clinical bacteriology, public health, and reference laboratories; it could be used in addition to a method targeting Shiga toxins (detection of stx genes by PCR, immunodetection of Shiga toxins in stool specimens, or Vero cell cytotoxicity assay) as an alternative to O157 culture medium. This combined approach should allow rapid visualization of both putative O157 and non-O157 STEC colonies for subsequent characterization, essential for real-time surveillance of STEC infections and investigations of outbreaks. C ertain strains of Shiga toxin-producing Escherichia coli (STEC) are important causes of food-borne disease in industrialized countries. The clinical manifestations of STEC infections range from mild diarrhea to severe and specific complications, such as hemolytic-uremic syndrome (HUS), which occurs primarily in young children (1, 2). These STEC strains associated with human infections are also called enterohemorrhagic E. coli (EHEC). Animals, and especially cattle, serve as reservoirs for STEC. Transmission occurs via ingestion of contaminated food or water, person-to-person contact, direct animal contact, and exposure to the environment. STEC strains are characterized by their ability to produce toxins related to those of Shigella dysenteriae type 1 (3): two types have been described among STEC isolates, Shiga toxin 1 and Shiga toxin 2, respectively, encoded by the stx 1 and stx 2 genes carried on temperate bacteriophages (4, 5). Most STEC isolates also carry the chromosomally located locus of enterocyte effacement (LEE), a pathogenicity island, first described in enteropathogenic E. coli (EPEC). LEE promotes the development of attaching-and-effacing lesions in the host intestinal mucosa c...

show abstract

Usability and Performance of CHROMagar STEC Medium in Detection of Shiga Toxin-Producing Escherichia coli Strains

Cited by 74 publications

References 24 publications

Assessing the Public Health Risk of Shiga Toxin-Producing Escherichia coli by Use of a Rapid Diagnostic Screening Algorithm

Assessing the Public Health Risk of Shiga Toxin-Producing Escherichia coli by Use of a Rapid Diagnostic Screening Algorithm

Performance of Sa Select , a Chromogenic Medium for Detection of Staphylococci in Clinical Specimens

Evaluation of CHROMagar STEC and STEC O104 Chromogenic Agar Media for Detection of Shiga Toxin-Producing Escherichia coli in Stool Specimens

Contact Info

Product

Resources

About