Shigella spp.

I. Organism Information

A. Taxonomy Information
  1. Species:
    1. Shigella. :
      1. GenBank Taxonomy No.: 620
      2. Description: In 1898, Japanese bacteriologist K. Shiga used bacterial culture to investigate an epidemic of acute dysentery in Japan. Using the serum from one of his patients, he was able to identify the epidemic agent in the feces of 34 out of 36 cases. Shiga characterized these bacteria by simple biochemical tests. The organism was named Shiga bacillus. Shigella spp. cause dysentery by invading the colonic mucosa. Shigella bacteria multiply within colonic epithelial cells, cause cell death and spread laterally to infect and kill adjacent epithelial cells, causing mucosal ulceration, inflamation and bleeding. Complications of Shigella infection are haemolytic-uraemic syndrome (HUS), seizures, sepsis, and toxic megacolon. Shigella infections are more severe in children who are malnourished and have a greater adverse effect on nutritional status than do infections with enteric pathogens that cause watery diarrhea. In several areas of the world, Shigella bacteria are resistant to available and affordable antibiotics (Website2).
      3. Variant(s):
        • Shigella flexneri. :
          • GenBank Taxonomy No.: 623
          • Description: Simon Flexner, in the early 1900s, first isolated a mannitol-fermenting strain of Shigella from dysentery patients in the Philippines which has now been designated as Shigella flexneri. As it is a highly infectious pathogen, the infectious dose of S. flexneri is extremely low. Bacteria are spread by personal contact or exposure to contaminated food and water, creating severe outbreaks in areas of minimal sanitary conditions. S. flexneri is the predominant specie in endemic areas, accounting for approximately 50% of culture-positive disease (Website2).
B. Lifecycle Information :
  1. Shigella lifecycle one stage (Website4, Website5, Website6):
    1. Shape: Shigella cells are rod-shaped.
    2. Picture(s):
      1. SEM Image of Shigella dysenteriae (Website 63):

        Description: Scanning Electron Micrograph of Shigella dysenteriae - Gram-negative, enteric, facultatively anaerobic, rod prokaryote; causes bacterial dysentery. This species is most often found in water contaminated with human feces. Magnification: x2,200.
      2. SEM Image of Shigella sonnei (Website 63):

        Description: Scanning Electron Micrograph of Shigella sonnei - Gram-negative, facultatively anaerobic, rod prokaryote; causes shigellosis (bacterial dysentery). This species is most often linked to infection from food. Magnification: x3,500.
    3. Other:
      1. ShigellaShigella are nonmotile, nonspore-forming, facultatively anaerobic gram-negative bacilli from the family Enterobacteriaceae.
C. Genome Summary:
  1. Genome of Shigella flexneri.
    1. Shigella Chromosome:
      1. GenBank Accession Number: AE005674
      2. Size: 4, 607 kb (Jin et al., 2002, Website40).
      3. Gene Count: 4,434 open reading frames (Jin et al., 2002, Website40).
      4. Description: There are several potential bacteriophage-transmitted PAIs (pathogenicity islands), many translocations, inversions and deletions of the corresponding E. coli DNA segments, and numerous pseudogenes. The presence of large numbers of pseudogenes has been postulated to be one of the main reasons that Shigella became a solely human pathogen (Jin et al., 2002).
    2. Shigella Plasmid pCP301:
      1. GenBank Accession Number: AF386526
      2. Size: 221 618 bp (Jin et al., 2002).
      3. Gene Count: 267 open reading frames (Jin et al., 2002, Website41).
      4. Description: Shigella flexneri 2a strain 301 virulence plasmid pCP301 (Jin et al., 2002, Website41).

II. Epidemiology Information

A. Outbreak Locations:
  1. Shigella is the primary causative agent of bacillary dysentery throughout the developing world. According to the World Health Organisation, the annual number of Shigella episodes throughout the world was estimated to be 164.7 million, of which 163.2 million were in developing countries (with 1.1 million deaths) and 1.5 million in industrialized countries. A total of 69% of all episodes and 61% of all deaths attributable to shigellosis involved children under 5 years of age (Kotloff et al., 1999). Shigella infection in the USA. A total of 59,527 cases of laboratory-confirmed Shigella infection were reported to the US National Shigella Surveillance System over the 5-year period 1990-94 (average 11,900 per year) (Kotloff et al., 1999). Over the same period, an additional 27,899 cases were reported from states not participating in the US National Shigella Surveillance System, yielding a total number of 87,426 Shigella cases for the USA, i.e. an average of 17500-18000 cases per year (Kotloff et al., 1999, Website9). This corresponds to 6.5 cases per 100,000 population (Kotloff et al., 1999). Shigellosis, which continues to have an important global impact, cannot be adequately controlled with the existing prevention and treatment measures (Kotloff et al., 1999).
B. Transmission Information:
  1. From: Homo sapiens To: Homo sapiens
    Mechanism: Shigella bacteria are spread from one infected person to another through fecal-oral transmition. Shigella cells are present in the diarrheal stools of infected persons while they are sick and for a week or two afterwards. Persons who have a Shigella infection have Shigella bacteria in their stool and frequently have Shigella bacteria on their hands. Vehicles - food and water. Food prepared by this person may easily become contaminated with Shigella bacteria. Water usually becomes contaminated with Shigella bacteria when sewage enters the drinking water supply. Approximately 20% of cases of shigellosis are transmitted via contaminated food or water (Mead et al., 1999).

C. Environmental Reservoir:
  1. Environmental Reservoir :
    1. Description: Humans are the only natural reservoir (Website22).
    2. Survival Information: Shigella may survive in faecally contaminated materials but not very long (Zaika, 2002). Shigella cells are known to survive in soiled linen for up to seven weeks, in fresh water from five to eleven days, in salt water for 12-30 hours, in dust at room temperature for six weeks, in sour milk for four weeks, and in kitchen refuse for approximately 1-4 days. Shigella survived for up to 14 days in tomato juice and apple juice stored at 7 degrees celcius. The shortest survival time (2-8 d) was observed in apple juice at 22 degrees celcius. Shigella cells were recovered after 48 h from strawberries and fruit salad kept at 4 degrees celcius (Bagamboula et al., 2002). Shigella organisms are killed by heat used in processing or cooking, and they do not survive well in acidic foods (pH below 4.5) (Website6, Website11, Zaika, 2002, Website17, Website26, Bagamboula et al., 2002).
D. Intentional Releases:
  1. Intentional Release information :
    1. Description: Shigella infection.
    2. Emergency contact: If you believe that you have been exposed to a biological or chemical agent, or if you believe an intentional biological threat will occur or is occurring, contact your local health department and/or your local police or other law enforcement agency. CDC Emergency Response Hotline (24 hours) 770-488-7100. Call communicable disease epidemiology 206-361-2914 or the food program 360-586-1249. Call USDA's Meat and Poultry Hotline at 1-800-535-4555, 10 a.m. to 4 p.m., Eastern Time. In the Washington, DC area, call (202) 720-3333. TTY: 1-800-256-7072 (Website7, Website8).

III. Infected Hosts

  1. Human:
    1. Taxonomy Information:
      1. Species:
        1. Human:
          • GenBank Taxonomy No.: 9606
          • Scientific Name: Homo sapiens (Website39)
          • Description: Only people (and possibly monkeys) can spread Shigella. Common pets, farm animals, and wild animals cannot spread these bacteria (Website3).

    2. Infection Process:
      1. Infectious Dose: Infectious dose is 10-1000 bacterial cells (Website13, Website17).
      2. Description: Shigella infection is characterized by invasion of the intestinal mucosa. The invasive process remains localized to the colonic and rectal mucosa, thereby causing major inflammatory destruction that accounts for a dysenteric syndrome, thus the bacillary dysentery. In many cases, however, shigellosis causes only a watery diarrhea comparable to that observed with noninvasive pathogens (Weir, 2002).

    3. Disease Information:
      1. Bacillary dysentery, Shigellosis :
        1. Pathogenesis Mechanism: Shigella is the causative agent of bacillary dysentery in humans. Colonization of intestinal epithelial cells by this pathogen induces an intense inflammatory reaction that leads to destruction of the colonic mucosa (Sansonetti, 1998). Shigella has the ability to enter epithelial cells and to spread from cell to cell, properties that are key determinants of bacterial virulence (Parsot and Sansonetti, 1996). Upon contact with epithelial cells, Shigella induces the formation of cell extensions that reach several tens of microns in length, rise above the apical cell surface at the site of bacterial interaction, and engulf the bacterium in a large vacuole in a process reminiscent of macropinocytosis (Sansonetti and Egile, 1998, Nhieu and Sansonetti, 1999). Once internalized, Shigella lyses the phagosomal membrane and multiplies freely in the cell cytosol. During this multiplication phase, Shigella moves intracellularly by polymerizing actin at one pole of the bacterial body (Sansonetti and Egile, 1998). Using this actin-based motility, the bacterium induces protrusions that invade neighboring cells. After lysis of both protrusion and recipient cell membranes, Shigella reinitiates its intercellular cycle and can spread within the cell monolayer without an extracellular step. Both cell entry and intracellular motility are examples of bacterial manipulation of processes controlling the host cytoskeletal dynamics (Sansonetti, 1998, Parsot and Sansonetti, 1996, Sansonetti and Egile, 1998, Nhieu and Sansonetti, 1999).

        2. Incubation Period: The Shigella infection incubation period is usually 16 to 72 hours (but may range 12 to 96 hours) after being exposed (Website15, Website16).

        3. Prognosis: The Shigella infection is generally self-limited. The infection usually resolves in 5 to 7 days but in some persons, especially young children and the elderly, the diarrhea can be so severe that the patient requires hospitalization (Website18, Website19).

        4. Diagnosis Overview: The diagnosis of Shigellosis is usually made by finding Shigella bacteria in a stool sample. This is most often accomplished by collecting a stool specimen from the ill patient and sending it to a laboratory for analysis. During Shigellosis, Shigella cells are excreted in large numbers in the stool (10e6-10e8 bacterial cells per gram) (Website24, Website25, Website26).

        5. Symptom Information :
          • Shigella Infection Symptoms:
            • Description: Symptoms: Acute abdominal pain or cramping: This symptom is pain in the abdominal area, stomach region, or belly (often referred to as stomach pain). Tenesmus (crampy rectal pain): Tenesmus is the constant feeling of the need to empty the bowel, accompanied by pain, cramping, and involuntary straining efforts. Watery diarrhea: The passage of an increased amount of stool. This is frequently considered to be 3 or more stools per day, or excessively watery and unformed stool. Chronic diarrhea occurs when loose or more frequent stools persist for longer than two weeks. Nausea and vomiting: Nausea is the sensation leading to the urge to vomit. To vomit is to force the contents of the stomach up through the esophagus and out of the mouth. Acute fever: Normal body temperature varies amongst people, but the average is 98.6 degrees fahrenheit (37 degrees celcius). If the temperature is 99 to 100 degrees fahrenheit, this may represent a low-grade fever. Body temperature of 100 degrees fahrenheit or above is classified as fever. Blood, mucus, or pus in stool: Blood in the stool; Stool - black or tarry (Website20, Website21, Website22, Website23).

        6. Treatment Information:
          • Oral rehydration. : Mild to moderate dehydration is common in patients with Shigellosis. Dehydration is caused by loss of fluid in stools, evaporation of water through the skin due to fever, and reduced fluid intake because of anorexia. Hyponatraemia (low levels of sodium in the blood) is a particular problem for Shigellosis. Oral rehydration therapy should be given and in most cases. Giving intravenous fluids increases the risk of infection and is expensive. Oral rehydration solution contains enough sodium to increase its level in the patient's blood, if it is low (Website27).
            • Applicable: Shigella infection.
          • Antibiotic-Ciprofloxacin. : Ciprofloxacin (Cipro) -- Fluoroquinolone with activity against streptococci, Salmonella, and most gram-negative organisms, but has no activity against anaerobes. Inhibits bacterial DNA synthesis and, consequently, bacterial growth. Adult Dose: A normal prescription of cipro would consist of 1,500mg tablet every 12 hours (2x daily) for 7-10 days. A stronger regimen of cipro would consist of 1,500mg tablet every 8 hours (3x daily) for 7-10 days. Pediatric Dose: Not recommended 18 years - Administer as in adults (Website28, Website29).
            • Applicable: Shigella infection.
            • Contraindicator: Ciprofloxacin is contraindicated in patients with documented hypersensitivity (Website29).
            • Complication: Coadministration with antacids, iron salts, and zinc salts may reduce serum levels; administer antacids 2-4 h before or after taking fluoroquinolones; cimetidine may interfere with metabolism of fluoroquinolones; reduces therapeutic effects of phenytoin; probenecid may increase serum concentrations; may increase toxicity of theophylline, caffeine, cyclosporine, and digoxin (monitor digoxin levels); may increase effects of anticoagulants (Website29).
            • Drug Resistance: A few strains showed intermediate susceptibility to ciprofloxacin (4%) by disk diffusion test (Dutta et al., 2002).
          • Antibiotic-Cotrimoxazole. : Cotrimoxazole (also called trimethoprim (TMP) - sulfamethoxazole (SMX). Sulfonamide derivative. Inhibits bacterial growth by blocking synthesis of dihydrofolic acid. Adult Dose: TMP 160mg and SMX 800mg twice a day for 5 days. Children: TMP 5mg/kg and SMX 25mg/kg twice a day for 5 days. Pediatric Dose: Less then 2 months: Not recommended. More then 2 months: 8-10 mg/kg/d PO divided bid (based on TMP component) (Website29, Website30).
            • Applicable: Shigella infection.
            • Contraindicator: Cotrimoxazole is contraindicated in patients with documented hypersensitivity (Website29).
            • Complication: Coadministration with dapsone may increase blood levels of both drugs; coadministration of diuretics increases incidence of thrombocytopenia purpura in elderly patients; phenytoin levels may increase with coadministration; may potentiate effects of methotrexate in bone marrow depression; hypoglycemic response to sulfonylureas may increase with coadministration; may increase levels of zidovudine (Website29).
            • Drug Resistance: Shigella resistance to cotrimoxazole was observed in 34% of the Shigella isolates (Batikhi, 2002).
          • Antibiotic-Norfloxacin. : First introduced in 1986, norfloxacin belongs to a class of drugs called fluoroquinolones. Norfloxacin is a very potent antibiotic that can block the function of DNA gyrase needed for DNA replication. Dose: 400mg twice a day (interval 12 hours) for 7-10 days (Website31, Website32).
            • Applicable: Shigella infection.
            • Contraindicator: Patients hypersensitive to norfloxacin or chemically related quinolones. Pregnancy and lactation (Website33).
            • Drug Resistance: Antimicrobial susceptibility testing of Shigella spp. showed a high degree of resistance to the commonly used antimicribials, including ampicillin (41%), cotrimoxazole (95%), tetracycline (87%), and nalidixic acid (59%), and low level resistance against norfloxacin (9%) and ciprofloxacin (6%) (Noyogi and Pazhani, 2003).
          • Antibiotic-Ampicillin. : Used in treatment of gastroenteritis, invasive disease, and enteric fever. Adult Dose: 500-3000 mg IV q4-6h; not to exceed 12 g/d. Pediatric Dose: 200-300 mg/kg/d IV divided q6h; not to exceed 12 g/d (Website29).
            • Applicable: Shigella infection.
            • Contraindicator: Documented hypersensitivity interactions. Coadministration with allopurinol may increase risk of rash (Website29).
            • Complication: Pregnancy: Usually safe but benefits must outweigh the risks. Adjust dose in renal failure; breastfeeding infants may have bowel flora modification, allergic response, and interference of culture results for fever workup (Website29).
            • Drug Resistance: Shigella resistance to ampicillin was observed in 77.0% of the Shigella isolates (Batikhi, 2002).

    4. Prevention:
      1. Preventing Shigellosis:
        • Description: How can a Shigella infection be prevented? The spread of Shigella from an infected person can be stopped by frequent and careful hand washing with soap and water. People who have shigellosis or any diarrhea should not prepare food for others until they have been shown to no longer be carrying the bacterium. Basic food safety precautions will also help to prevent shigellosis. Shigella organisms are killed by heat used in cooking. Drink water only if it has been chlorinated (most tap water) or treated with ozone (most bottled water). Consume only pasteurized dairy products. Simple precautions taken while traveling to the developing world can prevent getting shigellosis. Drink only treated or boiled water, and eat only cooked hot foods or fruits you peel yourself. The same general precautions can prevent traveler's diarrhea caused by all pathogens (Meng and Doyle, 2002, Website12).

    5. Model System:

      No model system information is currently available here.

IV. Labwork Information

A. Biosafety Information:
  1. General biosafety information :
    • Biosafety Level: Biosafety Level 2.
    • Precautions:
      • Shigella may be present in feces, urine, and in food, feed, and environmental materials. Ingestion or parenteral inoculation are the primary laboratory hazards. The importance of aerosol exposure is not known. Recommended Precautions: Biosafety Level 2 practices, containment equipment, and facilities are recommended for activities with clinical materials and cultures known to contain or potentially contain the microorganism. Animal Biosafety Level 2 practices, containment equipment, and facilities are recommended for activities with experimentally or naturally infected animals (Website34).
B. Culturing Information:
  1. Shigella Culturing Method :
    1. Description: Shigella Broth (Website35).

    2. Medium:
      1. BROTH BASE: Tryptone 20 g. K2HPO4 2 g. KH2PO4 2 g. NaCl 5 g. Glucose 1 g. Tween 80 1.5 ml. Distilled water 1.0 liter. Autoclave 15 min at 121 degrees celcius. Final pH, 7.0 0.2. NOVOBIOCIN SOLUTION: Weigh 50 mg novobiocin into 1 liter distilled water. Sterilize by filtration through 0.45 m membrane. Add 2.5 ml of this concentrated novobiocin solution to 225 ml base. Final concentration of novobiocin (0.55 g/ml). This broth is a specially formulated medium for Shigella, novobiocin is added to provide a selective environment. Pour supernatant into sterile 500 ml Erlenmeyer flask. Adjust pH, if necessary, to 7.0 0.2 with sterile 1 N NaOH or 1 N HCl. Place flask in anaerobic jar with fresh catalyst, insert GasPak and activate by adding water. Incubate jars in water bath for 20 h (Website35).
    3. Optimal Temperature: Incubate jars in 44 degrees celcius water bath (Website35).
    4. Optimal pH: Final pH 7.0 0.2 (Website35).
C. Diagnostic Tests :
  1. Organism Detection Tests:
    1. Gram Staining:
      1. Time to Perform: minutes-to-1-hour
      2. Description: Shigella cells are Gram (-) bacilli. Gram-staining is a four- part procedure which uses certain dyes to make a bacterial cell stand out against its background. The specimen should be mounted and heat fixed on a slide before you proceed to stain it (Website36, Website37).
      3. False Positive: Not using enough decolorizer may yield a false Gram (+) result (Website36).
      4. False Negative: Using too much decolorizer could result in a false Gram (-) result (Website36).

  2. Immunoassay Tests:

    No immuno-assay tests available here.

  3. Nucleic Acid Detection Tests: :
    1. Islam's Shigella PCR Detection:
      1. Time to Perform: 1-hour-to-1-day
      2. Description: Stool samples were collected from 41 patients with dysentery. DNA was extracted from the stool samples, and the target sequence of invasive plasmid antigen (ipaH) locus was amplified by PCR. The results of the PCR technique showed that a 700 bp fragment was generated in 18 of the 18 culture-positive and in 7 of the 23 culture-negative stools (Islam et al., 1998).
      3. Primers:
        • H8/15
          • Reverse: GCCGGTCAGCCACCCTA
          • Product
    2. Theron's Shigella Seminested PCR Detection:
      1. Time to Perform: 1-hour-to-1-day
      2. Description: A rapid seminested polymerase chain reaction (PCR) method for the specific, sensitive detection of virulent Shigella in spiked environmental water samples was developed. The PCR procedure coupled with an enrichment culture incubated for 6 h to detect Shigella organisms in culture. Treated sewage, ground, surface and drinking water samples, collected from various sources were seeded with Shigella and incubated in broth for 6 h before detection by seminested PCR. The primers specific for the invasion plasmid antigen gene (ipaH) of virulent Shigella produced a 620-bp fragment that was used as template for the seminested primer pair delineating a 400-bp fragment (Theron et al., 2001).
      3. Primers:
        • H8/15
          • Reverse: GCCGGTCAGCCACCCTC
          • Product
        • H8/10
          • Product
    3. Kong's Shigella PCR Detection:
      1. Time to Perform: 1-hour-to-1-day
      2. Description: The invasion plasmid antigen H (ipaH) gene of Shigella was used as the gene target for a rapid PCR method that allows the simultaneous detection, in a single tube, of six commonly encountered waterborne pathogens. The PCR assay developed in this study could provide a cost-effective and informative supplement to conventional microbiological methods for routine monitoring and risk assessment of water quality. The PCR assay was specific and rapid (Kong et al., 2002).
      3. Primers:
        • IpaH
          • Product
    4. Dutta's Shigella PCR Detection:
      1. Time to Perform: 1-hour-to-1-day
      2. Description: Enriched stool samples were subjected to PCR to amplify the target sequence of the invasive plasmid antigen (ipaH) locus, a multicopy element found on the chromosome and invasion plasmid. The stool PCR was positive in 24 of the 26 culture-positive and in 22 culture-negative stools. The sensitivity of enriched stool culture, colony hybridisation, and enriched stool PCR was found to be 54%, 60% and 96%, respectively, when each of the methods was compared to the total microbiologically confirmed cases of dysentery (Dutta et al., 2001).
      3. Primers:
        • IpaH
          • Product

    5. PCR-ELISA:
      1. Time to Perform: 1-hour-to-1-day
      2. Description: Detection of PCR products of the ipaH gene from Shigella by enzyme linked immunosorbent assay (ELISA) in diarrheal stool samples. The PCR-ELISA system involves the initial amplification of the target sequence incorporating a nucleotide (dUTP) labeled with digoxigenin. This labeled target sequence is then hybridized to a complementary ipaH-derived oligonucleotide that itself is labeled with biotin. Biotin forms a strong association with streptavidin, which is commercially available on a ready made ELISA plate; thus the hybrid digoxigenin-target sequence-biotin complex is added to the ELISA plate and binds via the biotin-streptavidin interaction. Detection of the bound complex is accomplished via a simple alkaline phosphatase labeled antibody directed against digoxigenin, with color developed using a suitable substrate. Forward primer H8: GTTCCTTGACCGCCTTTCCGATACCGTC Reverse primer H15: GCCGGTCAGCCACCCTCTGAGAGTAC (Sethabutr et al., 2000).

  4. Other Types of Diagnostic Tests:

    No other tests available here.

V. References

A. Journal References:
Bagamboula et al., 2002: Bagamboula C, Uyttendaele M, Debevere J. Acid tolerance of Shigella sonnei and Shigella flexneri. Journal of Applied Microbiology. 2002; 93(3): 479 - 486. [PubMed: 12174047].
Batikhi, 2002: Batikhi M. Epidemiological study on Jordanian patients suffering from diarrhoea. The New Microbiologica. 2002; 25(4): 405 - 412. [PubMed: 12437219].
Dutta et al., 2001: Dutta S, Chatterjee A, Dutta P, Rajendran K, Roy S, Pramanik KC, Bhattacharya SK. Sensitivity and performance characteristics of a direct PCR with stool samples in comparison to conventional techniques for diagnosis of Shigella and enteroinvasive Escherichia coli infection in children with acute diarrhoea in Calcutta, India. Journal of Medical Microbiology. 2001; 50(8): 667 - 674. [PubMed: 11478669].
Dutta et al., 2002: Dutta S, Rajendran K, Roy V, Chatterjee A, Dutta P, Nair GB, Bhattacharya SK, Yoshida SI. Shifting serotypes, plasmid profile analysis and antimicrobial resistance pattern of shigellae strains isolated from Kolkata, India during 1995-2000. Epidemiology and Infection. 2002; 129(2): 235 - 243. [PubMed: 12403099].
Islam et al., 1998: Islam M, Hossain M, Hasan M, Rahman MM, Fuchs G, Mahalanabis D, Baqui AH, Albert MJ. Detection of Shigellae from stools of dysentery patients by culture and polymerase chain reaction techniques. Journal of Diarrhoeal Disease Research. 1998; 16(4): 248 - 251. [PubMed: 10453122].
Jin et al., 2002: Jin Q, Yuan Z, Xu J, Wang Y, Shen Y, Lu W, Wang J, Liu H, Yang J, Yang F, Zhang X, Zhang J, Yang G, Wu H, Qu D, Dong J, Sun L, Xue Y, Zhao A, Gao Y, Zhu J, Kan B, Ding K, Chen S, Cheng H, Yao Z, He B, Chen R, Ma D, Qiang B, Wen Y, Hou Y, Yu J. Genome sequence of Shigella flexneri 2a: insights into pathogenicity through comparison with genomes of Escherichia coli K12 and O157. Nucleic Acids Research. 2002; 30(20): 4432 - 4441. [PubMed: 12384590].
Kong et al., 2002: Kong R, Lee S, Law T, Law SH, Wu RS. Rapid detection of six types of bacterial pathogens in marine waters by multiplex PCR. Water Research. 2002; 36(11): 2802 - 2812. [PubMed: 12146868].
Kotloff et al., 1999: Kotloff K, Winickoff J, Ivanoff B, Clemens JD, Swerdlow DL, Sansonetti PJ, Adak GK, Levine MM. Global burden of Shigella infections: implications for vaccine development and implementation of control strategies. Bulletin of the World Health Organization. 1999; 77(8): 651 - 666. [PubMed: 10516787].
Mead et al., 1999: Mead P, Slutsker L, Dietz V, McCaig LF, Bresee JS, Shapiro C, Griffin PM, Tauxe RV. Food-related illness and death in the United States. Emerging Infectious Diseases. 1999; 5(5): 607 - 625. [PubMed: 10511517].
Meng and Doyle, 2002: Meng J, Doyle M. Introduction. Microbiological food safety. Microbes and Infection. 2002; 4(4): 395 - 397. [PubMed: 11932189].
Nhieu and Sansonetti, 1999: Nhieu G, Sansonetti P. Mechanism of Shigella entry into epithelial cells. Current Opinion in Microbiology. 1999; 2(1): 51 - 55. [PubMed: 10047558].
Noyogi and Pazhani, 2003: Noyogi SK, Pazhani GP Multiresistant Shigella Species Isolated from Childhood Diarrhea Cases in Kolkata, India. Japanese Journal of Infectious Diseases. 2003; 56(): 33 - 34. [PubMed: 10794934].
Parsot and Sansonetti, 1996: Parsot C, Sansonetti P. Invasion and the pathogenesis of Shigella infections. Current Topics in Microbiology and Immunology. 1996; 209: 25 - 42. [PubMed: 8742244].
Sansonetti, 1998: Sansonetti P. Molecular and cellular mechanisms of invasion of the intestinal barrier by enteric pathogens. The paradigm of Shigella. Folia Microbiologica. 1998; 43(3): 239 - 246. [PubMed: 9717250].
Sansonetti and Egile, 1998: Sansonetti P, Egile C. Molecular bases of epithelial cell invasion by Shigella flexneri. Antonie Van Leeuwenhoek. 1998; 74(4): 191 - 197. [PubMed: 10081579].
Sethabutr et al., 2000: Sethabutr O, Venkatesan M, Yam S, Pang LW, Smoak BL, Sang WK, Echeverria P, Taylor DN, Isenbarger DW. Detection of PCR products of the ipaH gene from Shigella and enteroinvasive Escherichia coli by enzyme linked immunosorbent assay. Diagnostic Microbiology and Infectious Disease. 2000; 37(1): 11 - 16. [PubMed: 10794934].
Theron et al., 2001: Theron J, Morar D, Du Preez M, Brozel VS, Venter SN. A sensitive seminested PCR method for the detection of Shigella in spiked environmental water samples. Water Research. 2001; 35(4): 869 - 874. [PubMed: 11235881].
Weir, 2002: Weir E. Shigella: wash your hands of the whole dirty business. Canadian Medical Association Journal. 2002; 167(3): 281 - 281. [PubMed: 12186178].
Zaika, 2002: Zaika L. Effect of organic acids and temperature on survival of Shigella flexneri in broth at pH 4. Journal of Food Protection. 2002; 65(9): 1417 - 1421. [PubMed: 12233851].
B. Book References:

No book references used.

C. Website References:
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Website2: The World Health Organization. Shigella. [ ].
Website3: Shigella an infectious foodborne illness. [ ].
Website4: World of Shigella. [ ].
Website5: Shigella picture. [ ].
Website6: MicroBioNet. [ ].
Website7: CDC. What to Do in an Emergency. [ ].
Website8: CDC. Information networks and other information sources. [ ].
Website9: Help for Shigellosis survivors. [ ].
Website10: Shigella fact sheet. [ ].
Website11: Shigella Infection. [ ].
Website12: About Shigella. [ ].
Website13: Shigella summary. [ ].
Website14: Food safety facts on Shigella. [ ].
Website15: I. Gastrointestinal infections and diarrhea. [ ].
Website16: II. Gastrointestinal infections and diarrhea. [ ].
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Website18: I. Shigella Enteritis. [ ].
Website19: The Doctor. Shigella. [ ].
Website20: II. Shigella Enteritis. [ ].
Website21: III. Shigella Enteritis. [ ].
Website22: eMedicine. Shigella Infection. [ ].
Website23: Food Safety Network. Shigella. [ ].
Website24: What You should know about shigellosis. [ ].
Website25: Pennhealth system. [ ].
Website26: Shigella - Dysentery. [ ].
Website27: Pediatrics: Vomiting, Diarrhea, and Dehydration. [ ].
Website28: Antibiotics. Cipro. [ ].
Website29: Salmonella, Shigella infection. [ ].
Website30: Shigellosis. Dialogue on diarrhea. [ ].
Website31: I. Norfloxacin. [ ].
Website32: II. Norfloxacin: Pharmacology. [ ].
Website33: III. Norfloxacin (Noroxin). [ ].
Website34: . CDC. Agent Summary Statements Section VII-A: Bacterial Agents. [ ].
Website35: Shigella Broth. [ ].
Website36: Gram-staining Procedure. [ ].
Website37: FDA. Microscopic Examination of Foods. [ ].
Website38: NCBI. Shigella flexneri. [ ].
Website39: NCBI. Homo sapiens. [ ].
Website40: NCBI. Shigella flexneri 2a. Complete genome. [ ].
Website41: Shigella flexneri 2a plasmid pCP301, complete sequence. [ ].
Website 63: Dennis Kunkel Microscopy, Inc. [ ].
D. Thesis References:

No thesis or dissertation references used.

VI. Curation Information