Editing Coliform bacteria (section)

== General ==
Typical genera include:<ref>{{cite report | title = The Microbiology of Drinking Water (2002) – Part 1 – Water Quality and Public Health | work = Environment Agency | location = Bristol, UK | url = http://www.standingcommitteeofanalysts.co.uk/archive/The_microbiology_of_drinking_water__part_1__water_quality_and_public_health_2002.pdf }}{{Dead link|date=December 2023 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>
* ''[[Citrobacter]] ''are [[peritrichous]] facultative anaerobic bacilli between 0.6–6 μm in length.<ref name=":3">{{Cite web | work = Public Health Agency of Canada |date=2012-04-30 |title=Pathogen Safety Data Sheets: Infectious Substances – Citrobacter spp. |url=https://www.canada.ca/en/public-health/services/laboratory-biosafety-biosecurity/pathogen-safety-data-sheets-risk-assessment/citrobacter.html |access-date=2022-03-23 }}</ref> ''Citrobacter'' species inhabit intestinal flora without causing harm, but can lead to urinary tract infections, [[bacteremia]], brain abscesses, [[pneumonia]], intra abdominal sepsis, meningitis, and joint infections if they are given the opportunity.<ref name=":3" /> Infections of a ''Citrobacter'' species has a mortality rate between 33–48%, with infants and [[immunocompromised]] individuals being more susceptible.<ref name=":3" />
* ''[[Enterobacter]] ''are motile, flagellated bacilli known for causing infections such as [[bacteremia]], respiratory tract infections, [[urinary tract infection]]s, infections of areas where surgery occurred, and in extreme cases [[meningitis]], [[sinusitis]] and [[osteomyelitis]].<ref name=":4">{{cite book | vauthors = Ramirez D, Giron M | chapter = Enterobacter Infections |date=2022 |url=http://www.ncbi.nlm.nih.gov/books/NBK559296/ | title = StatPearls |place=Treasure Island (FL) |publisher=StatPearls Publishing |pmid=32644722 |access-date=2022-03-23 }}</ref> To determine the presence of ''Enterobacter'' in a sample, they are first grown on MacConkey agar to confirm they are [[lactose]] fermenting.<ref name=":4" /> An indole test will differentiate ''Enterobacter'' from ''Escherichia'', as ''Enterobacter'' are [[indole]] negative and ''Escherichia'' is positive.<ref name=":4" /> ''Enterobacter'' are distinguished from ''Klebsiella'' because of their differences in motility.<ref name=":4" />
* ''[[Klebsiella]] ''are non-motile, Gram-negative bacilli ranging from 1–2 μm in length.<ref name=":5">{{cite book  | vauthors = Chart H | chapter = 27 – Klebsiella, enterobacter, proteus and other enterobacteria: Pneumonia; urinary tract infection; opportunist infection |date=2012-01-01 | title = Medical Microbiology | edition = Eighteenth |pages=290–297 | veditors = Greenwood D, Barer M, Slack R, Irving W |place=Edinburgh |publisher=Churchill Livingstone |language=en |doi=10.1016/b978-0-7020-4089-4.00042-1 |isbn=978-0-7020-4089-4 }}</ref> They are facultative anaerobes with a capsule composed of complex acid [[polysaccharide]]s that allows them to withstand drying for several months.<ref name=":5" /> ''[[Klebsiella pneumoniae]]'' is the most common ''Klebsiella'' species found in humans, the [[gastrointestinal tract]]s of animals, in sewage and in soil.<ref name="Berman_2019">{{cite book | vauthors = Berman JJ | chapter = Chapter 3 – Bacteria |date=2019-01-01  | title = Taxonomic Guide to Infectious Diseases | edition = Second |pages=39–119 | veditors = Berman JJ |publisher=Academic Press |language=en |doi=10.1016/b978-0-12-817576-7.00003-1 |isbn=978-0-12-817576-7 | s2cid = 239067047 }}</ref> On carbohydrate-rich media, ''Klebsiella'' colonies appear greyish-white in colour with a mucosal outer surface.<ref name=":5" /> The media used for selecting for ''Klebsiella'' species in a mixed sample is an agar including ornithine, raffinose, and Koser citrate, where members of this genus will form yellow, wet-looking colonies.<ref>{{cite journal | vauthors = Bruce SK, Schick DG, Tanaka L, Jimenez EM, Montgomerie JZ | title = Selective medium for isolation of Klebsiella pneumoniae | journal = Journal of Clinical Microbiology | volume = 13 | issue = 6 | pages = 1114–1116 | date = June 1981 | pmid = 7019238 | doi = 10.1128/jcm.13.6.1114-1116.1981 | pmc = 273960 }}</ref>
* ''[[Escherichia]] ''species normally inhabit the human intestine and those of other warm-blooded animals, and are the most commonly responsible for causing disease in humans.<ref name="Berman_2019" /> ''[[Escherichia coli]]'' specifically is the most common organism seen in the human intestine and are known to cause a variety of diseases in humans.<ref name=":7">{{Cite book | vauthors = Bennett JE, Dolin R, Blaser MJ |title=Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases  |publisher=Elsevier |date = August 2019 |isbn=9780323482554 |pages=2669–2685 |language=English}}</ref> Most ''E. coli'' strains are motile and have obtained many of their [[Virulence factor|virulence]] features from [[horizontal gene transfer]].<ref name=":7" /> There are several different pathotypes of ''E. coli'' causing [[Gastrointestinal tract|gastrointestinal]] syndromes: diarrheagenic ''E. coli'' (DEC), enterotoxigenic ''E. coli'' (ETEC); EPEC; Shiga toxin–producing''E. coli'' (STEC), which includes EHEC; enteroaggregative ''E. coli'' (EAEC); and enteroinvasive ''E. coli'' (EIEC).<ref name=":7" /> There are different ways to identify ''E. coli'' based on variation of their O, H and K polysaccharides on their cell surface or by using selective medias.

''[[Escherichia coli]]'' (''E. coli'') can be distinguished from most other coliforms by its ability to ferment lactose at 44&nbsp;°C in the [[fecal coliform]] test, and by its growth and color reaction on certain types of culture media. When cultured on an [[eosin methylene blue]] (EMB) plate, a positive result for ''E. coli'' is metallic green colonies on a dark purple medium. Also can be cultured on Tryptone Bile X-Glucuronide (TBX) to appear as blue or green colonies after incubation period of 24 hours. Escherichia coli have an incubation period of 12–72 hours with the optimal growth temperature being 37&nbsp;°C. Unlike the general coliform group, ''E. coli'' are almost exclusively of fecal origin and their presence is thus an effective confirmation of fecal contamination. Most strains of ''E. coli'' are harmless, but some can cause serious illness in humans. Infection symptoms and signs include [[human blood|bloody]] [[diarrhea]], [[stomach]] [[cramp]]s, [[vomiting]] and occasionally, [[fever]]. The bacteria can also cause [[pneumonia]], other [[respiratory illness]]es and [[urinary tract infection]]s.<ref>{{cite web |url=http://www.textbookofbacteriology.net/e.coli.html |title=Pathogenic ''E. coli'' |access-date=2007-11-30 | vauthors = Todar K |work=Online Textbook of Bacteriology |publisher=University of Wisconsin–Madison Department of Bacteriology}}</ref><ref>{{cite web | title=''Escherichia coli''| work=CDC National Center for Emerging and Zoonotic Infectious Diseases| url=https://www.cdc.gov/ecoli/index.html/ | access-date=2012-10-02}}</ref>

An easy way to differentiate between different types of coliform bacteria is by using an [[eosin methylene blue]] agar plate.<ref name=":0">{{cite journal | vauthors = Leininger DJ, Roberson JR, Elvinger F | title = Use of eosin methylene blue agar to differentiate Escherichia coli from other gram-negative mastitis pathogens | journal = Journal of Veterinary Diagnostic Investigation | volume = 13 | issue = 3 | pages = 273–275 | date = May 2001 | pmid = 11482612 | doi = 10.1177/104063870101300319 | s2cid = 22611000 | doi-access = free }}</ref> This plate is partially inhibitory to Gram (+) bacteria, and will produce a color change in the Gram (-) bacterial colonies based on lactose [[fermentation]] abilities.<ref name=":0" /> Strong lactose fermenters will appear as dark blue/purple/black, and ''E.coli'' (which also ferments lactose) colonies will be dark colored, but will also appear to have a metallic green sheen. Other coliform bacteria will appear as thick, slimy colonies, with non-fermenters being colorless, and weak fermenters being pink.{{citation needed|date=January 2021}}
[[File:Coli levine.JPG|thumb|''E. coli'' on EMB agar]]

=== Incidence of coliform outbreaks ===

==== ''Escherichia coli'' O157 ====
As of November 15, 2021, seven states in the USA declared ten cases of illnesses from an ''E. coli'' O157:H7 strain.<ref name=":8">{{Cite web | work = Center for Food Safety and Applied Nutrition |date=2022-01-06 |title=Outbreak Investigation of E. Coli O157:H7 – Spinach (November 2021) |url=https://www.fda.gov/food/outbreaks-foodborne-illness/outbreak-investigation-e-coli-o157h7-spinach-november-2021 | publisher = U.S. Food and Drug Administration  |language=en}}</ref> These cases were reported from October 15, 2021 through October 27, 2021 and an investigation was carried out by the Minnesota Department of Agriculture and FDA.<ref name=":8" /> It was concluded that packages of spinach collected from homes of infected people were contaminated with a strain of ''E. coli'' that matched the strain causing illness.<ref name=":8" /> This was determined by performing [[whole genome sequencing]] on the strain extracted from the spinach and comparing it to the strain taken from infected individuals.<ref name=":8" />

As of February 7, 2022, the provinces of Alberta and Saskatchewan in Canada reported a collective fourteen confirmed cases of ''E. coli'' O157 strain illnesses.<ref name=":9">{{Cite web | work = Public Health Agency of Canada |date=2022-01-29 |title=Public Health Notice: Outbreak of E. coli infections linked to Hankook (Korean characters only) brand Original Kimchi |url=https://www.canada.ca/en/public-health/services/public-health-notices/2022/outbreak-e-coli-infections-linked-handkook-brand-original-kimchi.html |access-date=2022-03-24 }}</ref> These were reported between December 2021 and January 2022, and the Public Health Agency of Canada (PHAC), the Canadian Food Inspection Agency (CFIA), and Health Canada were able to determine a specific brand of Original Kimchi to be the source of the organism.<ref name=":9" /> On January 28, 2022 and February 6, 2022, the CFIA issued a recall on Hankook Original Kimchi.<ref name=":9" />

=== Detection of coliform bacteria in drinking water ===

==== PCR ====
Amplification of the [[beta-galactosidase]] gene is used to detect coliforms in general, because all coliform organisms produce this compound.<ref name=":1">{{cite journal | vauthors = Rompré A, Servais P, Baudart J, de-Roubin MR, Laurent P | title = Detection and enumeration of coliforms in drinking water: current methods and emerging approaches | journal = Journal of Microbiological Methods | volume = 49 | issue = 1 | pages = 31–54 | date = March 2002 | pmid = 11777581 | doi = 10.1016/S0167-7012(01)00351-7 }}</ref> The [[Amplification of DNA|amplification]] of the beta-D glucuronidase is used to detect ''E. coli,'' or the amplification of their [[verotoxin]] gene(s) to detect verotoxin-producing ''E. coli.''<ref name=":1" /><ref>{{cite journal | vauthors = Holland JL, Louie L, Simor AE, Louie M | title = PCR detection of Escherichia coli O157:H7 directly from stools: evaluation of commercial extraction methods for purifying fecal DNA | journal = Journal of Clinical Microbiology | volume = 38 | issue = 11 | pages = 4108–4113 | date = November 2000 | pmid = 11060076 | pmc = 87549 | doi = 10.1128/JCM.38.11.4108-4113.2000 }}</ref>

==== Chemiluminescent in-situ hybridization ====
Specific areas of the [[16S rRNA]] in the ''Enterobacteriaceae'' genus are bound by [[oligonucleotide]] probes, which aids in monitoring the quality of drinking water.<ref name=":1" /> Specifically, ''E. coli'' is labelled with a soybean peroxidase-labeled peptide nucleic acid (PNA) probes that bind to a specific sequence in their 16S rRNA. When used in conjunction with a [[Chemiluminescence|chemiluminescent]] substrate, light is produced where each colony of ''E. coli'' is located, indicating that they are present in the sample.<ref>{{cite journal | vauthors = Stender H, Broomer AJ, Oliveira K, Perry-O'Keefe H, Hyldig-Nielsen JJ, Sage A, Coull J | title = Rapid detection, identification, and enumeration of Escherichia coli cells in municipal water by chemiluminescent in situ hybridization | journal = Applied and Environmental Microbiology | volume = 67 | issue = 1 | pages = 142–147 | date = January 2001 | pmid = 11133438 | pmc = 92533 | doi = 10.1128/aem.67.1.142-147.2001 | bibcode = 2001ApEnM..67..142S }}</ref>

==== Violet red bile agar ====
The solid medium is used to grow lactose-fermenting coliforms and utilizes a neutral red [[pH indicator]]. Pink colonies appear when lactose is fermented and are surrounded by [[bile]] that has [[Precipitation (chemistry)|precipitated]] out. To confirm if these colonies are coliforms, they are transferred to brilliant green lactose bile (BGLB) and incubated. If gas is visible after incubation, it can be confirmed that the sample had coliforms present.<ref name=":2">{{Citation |title=Water quality. Enumeration of Escherichia coli and coliform bacteria |url=http://dx.doi.org/10.3403/bseniso9308 |publisher=BSI British Standards |doi=10.3403/bseniso9308 |access-date=2022-03-03|url-access=subscription }}</ref>

==== Membrane filter method ====
Test samples are filtered through standard filter paper and then transferred to M-endo or LES Endo Agar mediums. Colonies appear pinkish-red with green metallic sheen after 22–24 hours of incubation. These colonies can be confirmed as coliforms if they are inoculated in [[Lauryl tryptose broth|lauryl tryptose]] (LST), produce gas, and then inoculated in BGLB. If there is gas production in the BGLB tubes, the test is positive for the presence of coliform bacteria.<ref name=":2" />{{clear}}