Salmonella spp salmonella typhi

Код	Наименование услуг	Цена, руб.	Доступность экспресс	Ед. измер.	Материалы	Заказать
022	Сальмонеллез с дифференцировкой (Salmonella spp., S. typhimurium, S. enteritidis)	850 p (Время исполнения до 72 часов)	1 исслед.	N V R E C

Животные: собаки, кошки, лошади, рептилии, птицы, МРС, КРС, грызуны

Цель исследования:
предназначен для выявления ДНК бактерий Salmonella spp. с дифференциацией типов Salmonella typhimurium и Salmonella enteridis методом полимеразной цепной реакции (ПЦР) с гибридизационно-флуоресцентной детекцией продуктов ПЦР в режиме реального времени

Для исследования используют:
1) Фекалии от птиц, рептилий
2) Ректальные смывы от млекопитающих
3) Молоко (для КРС, МРС),
4) Кровь с ЭДТА при подозрении на бактериемию и септицеми
5) Рвотные массы, промывные воды желудка.
6) Аутопсийный материал и биопсийный материал
паренхиматозные органы с очагами поражения
7) Абортированный плод и материал от него.
(не менее 3-х органов)

Правила отбора проб для исследования: 1) Для исследования фекалии собирается в стерильную посуду в количестве не менее 5 гр. Доставляется в лабораторию в течение 24 ч после взятия. 2) Венозная кровь отбирается в пробирки, содержащие антикоагулянт ЭДТА в количестве не менее 1 мл 3) Молоко от КРС и МРС собирается в стерильную посуду в количестве не менее 100 мл. Доставляется в лабораторию в течение 24 ч после взятия. 4) Рвотные массы, промывные воды желудка собирается в стерильную посуду в количестве не менее 50 мл. 5) Из органов и тканей вырезают кусочки не более 5 х 5 х 5 см, каждый орган помещается в отдельный герметичный пакет, подписывается. Органы, расфасованные в пакеты, от одного животного складываются в общий пакет и маркируются идентификатором животного. Доставляются в лабораторию в течение 2-х часов после отбора. При невозможности соблюсти данное требование, отобранный пат материал замораживается и через 1 сутки в замороженном виде доставляется в лабораторию, размораживание при транспортировке не допускается. 6) Абортированные плоды весом до 1 кг берется целиком. Плод помещается в отдельный чистый пакет, маркируется. Если вес плода более 1 кг, то необходимо оформить в БД вскрытие плода и взятие органов для исследования (паренхиматозные органе не менее 3-х проб). Стабильность ДНК в пробах: Материал хранится: • клинического материала (кровь, молоко) до проведения исследования хранится в холодильной камере в течение суток при температуре от 2 °С до 8 °С. • Секционный материал (паренхиматозные органы) хранить в морозильной камере 1 неделю при температуре не выше минус 16 °С, длительно – при температуре не выше минус 68 °С

1. Сальмонеллёзы распространены повсеместно. 2. Переносчиками сальмонеллёзов выступают как млекопитающие и птицы, так и рептилии, амфибии, рыбы и членистоногие, в т.ч. с\х животные, собаки, кошки, грызуны, домашняя птица, экзотические животные, рептилии, аквариумные рыбы. 3. Сальмонеллы подразделяются на несколько типов: узкоспециализированные (заражают только определённых хозяев), ограниченные (в основном заражают определённого хозяина, но иногда могут заражать и других животных\человека) и общего типа (широко распространены, заражают большой спектр хозяев). К общему типу относят S. Typhimurium и S. Enteritidis. 4. Переносчиками S. Typhimurium и S. Enteritidis являются все виды животных, перечисленные в пункте 2. На долю этих типов сальмонелл приходится 75% всех изолятов, выделяемых в настоящее время от больных людей, что указывает на их высокую распространённость и высокую патогенность. Необходимость определения этих типов сальмонелл у домашних животных связана с их высокой эпизоотологической опасностью для животных и хозяина-человека. 5. Редко встречающиеся типы сальмонелл также представляют опасность как для здоровья животных, так и для здоровья человека, однако распространены локально. Поэтому для диагностики этих типов подходят тест-системы, определяющие сальмонелл до рода (Salmonella spp.), без определения серотипов. Это особенно важно при работе с с\х и экзотическими животными

Key facts

• Salmonella is 1 of 4 key global causes of diarrhoeal diseases.
• Most cases of salmonellosis are mild; however, sometimes it can be life-threatening. The severity of the disease depends on host factors and the serotype of Salmonella.
• Antimicrobial resistance is a global public health concern and Salmonella is one of the microorganisms in which some resistant serotypes have emerged, affecting the food chain.
• Basic food hygiene practices, such as "cook thoroughly", are recommended as a preventive measure against salmonellosis.

Salmonella is a gram negative rods genus belonging to the Enterobacteriaceae family. Within 2 species, Salmonella bongori and Samonella enterica, over 2500 different serotypes or serovars have been identified to date. Salmonella is a ubiquitous and hardy bacteria that can survive several weeks in a dry environment and several months in water.

While all serotypes can cause disease in humans, a few are host-specific and can reside in only one or a few animal species: for example, Salmonella enterica serotype Dublin in cattle and Salmonella enterica serotype Choleraesuis in pigs. When these particular serotypes cause disease in humans, it is often invasive and can be life-threatening. Most serotypes, however, are present in a wide range of hosts. Typically, such serotypes cause gastroenteritis, which is often uncomplicated and does not need treatment, but disease can be severe in the young, the elderly, and patients with weakened immunity. This group features Salmonella enterica serotype Enteritidis and Salmonella enterica serotype Typhimurium, the two most important serotypes of Salmonella transmitted from animals to humans in most parts of the world.

The disease

Salmonellosis is a disease caused by the bacteria Salmonella. It is usually characterized by acute onset of fever, abdominal pain, diarrhoea, nausea and sometimes vomiting.

The onset of disease symptoms occurs 6–72 hours (usually 12–36 hours) after ingestion of Salmonella, and illness lasts 2–7 days.

Symptoms of salmonellosis are relatively mild and patients will make a recovery without specific treatment in most cases. However, in some cases, particularly in children and elderly patients, the associated dehydration can become severe and life-threatening.

Although large Salmonella outbreaks usually attract media attention, 60–80% of all salmonellosis cases are not recognized as part of a known outbreak and are classified as sporadic cases, or are not diagnosed as such at all.

Sources and transmission

• Salmonella bacteria are widely distributed in domestic and wild animals. They are prevalent in food animals such as poultry, pigs, and cattle; and in pets, including cats, dogs, birds, and reptiles such as turtles.
• Salmonella can pass through the entire food chain from animal feed, primary production, and all the way to households or food-service establishments and institutions.
• Salmonellosis in humans is generally contracted through the consumption of contaminated food of animal origin (mainly eggs, meat, poultry, and milk), although other foods, including green vegetables contaminated by manure, have been implicated in its transmission.
• Person-to-person transmission can also occur through the faecal-oral route.
• Human cases also occur where individuals have contact with infected animals, including pets. These infected animals often do not show signs of disease.

Treatment

Treatment in severe cases is electrolyte replacement (to provide electrolytes, such as sodium, potassium and chloride ions, lost through vomiting and diarrhoea) and rehydration.

Routine antimicrobial therapy is not recommended for mild or moderate cases in healthy individuals. This is because antimicrobials may not completely eliminate the bacteria and may select for resistant strains, which subsequently can lead to the drug becoming ineffective. However, health risk groups such as infants, the elderly, and immunocompromised patients may need to receive antimicrobial therapy. Antimicrobials are also administered if the infection spreads from the intestine to other body parts. Because of the global increase of antimicrobial resistance, treatment guidelines should be reviewed on a regular basis taking into account the resistance pattern of the bacteria based on the local surveillance system.

Prevention methods

Prevention requires control measures at all stages of the food chain, from agricultural production, to processing, manufacturing and preparation of foods in both commercial establishments and at home.

Preventive measures for Salmonella in the home are similar to those used against other foodborne bacterial diseases (see recommendations for food handlers below).

The contact between infants/young children and pet animals that may be carrying Salmonella (such as cats, dogs, and turtles) needs careful supervision.

National and regional surveillance systems on foodborne diseases are important means to know and follow the situation of these diseases and also to detect and respond to salmonellosis and other enteric infections in early stages, and thus to prevent them from further spreading.

Recommendations for the public and travellers

The following recommendations will help ensure safety while travelling:

• Ensure food is properly cooked and still hot when served.
• Avoid raw milk and products made from raw milk. Drink only pasteurized or boiled milk.
• Avoid ice unless it is made from safe water.
• When the safety of drinking water is questionable, boil it or if this is not possible, disinfect it with a reliable, slow-release disinfectant agent (usually available at pharmacies).
• Wash hands thoroughly and frequently using soap, in particular after contact with pets or farm animals, or after having been to the toilet.
• Wash fruits and vegetables carefully, particularly if they are eaten raw. If possible, vegetables and fruits should be peeled.

• A guide on safe food for travellers

Recommendations for food handlers

WHO provides the following guidance for people handling food:

• Both professional and domestic food handlers should be vigilant while preparing food and should observe hygienic rules of food preparation.
• Professional food handlers who suffer from fever, diarrhoea, vomiting or visible infected skin lesions should report to their employer immediately.
• The WHO Five keys to safer food serve as the basis for educational programmes to train food handlers and educate consumers. They are especially important in preventing food poisoning. The five keys to Safer Food are:
  • keep clean
  • separate raw and cooked
  • cook thoroughly
  • keep food at safe temperatures
  • use safe water and raw materials.

• Five keys to safer food

Recommendations for producers of fruits, vegetables and fish

The WHO Five keys to growing safer fruits and vegetables: promoting health by decreasing microbial contamination and the Five keys to safer aquaculture products to protect public health provide rural workers, including small farmers who grow fresh fruits and vegetables and fish for themselves, their families and for sale in local market with key practices to prevent microbial contamination.

The Five keys to growing safer fruits and vegetables are:

• Practice good personal hygiene.
• Protect fields from animal faecal contamination.
• Use treated faecal waste.
• Evaluate and manage risks from irrigation water.
• Keep harvest and storage equipment clean and dry.

• Five keys to growing safer fruits and vegetables

The Five keys to safer aquaculture products to protect public health are:

• Practice good personal hygiene.
• Clean the pond site.
• Manage water quality.
• Keep fish healthy.
• Use clean harvest equipment and containers.

• Five keys to safer aquaculture products to protect public health

WHO response

In partnership with other stakeholders, WHO is strongly advocating the importance of food safety as an essential element in ensuring access to safe and nutritious diets. WHO is providing policies and recommendations that cover the entire food chain from production to consumption, making use of different types of expertise across different sectors.

WHO is working towards the strengthening of food safety systems in an increasingly globalized world. Setting international food safety standards, enhancing disease surveillance, educating consumers and training food handlers in safe food handling are amongst the most critical interventions in the prevention of foodborne illnesses.

WHO is strengthening the capacities of national and regional laboratories in the surveillance of foodborne pathogens, such as Campylobacter and Salmonella.

WHO is also promoting the integrated surveillance of antimicrobial resistance of pathogens in the food chain, collecting samples from humans, food and animals and analysing data across the sectors.

WHO, jointly with FAO, is assisting Member States by coordinating international efforts for early detection and response to foodborne disease outbreaks through the network of national authorities in Member States.

WHO also provides scientific assessments as basis for international food standards, guidelines and recommendations developed by the FAO/WHO Codex Alimentarius Commission to prevent foodborne diseases.

Salmonella spp., which includes the agents of typhoid fever, Salmonella typhi, paratyphi and non-typhoidal serotypes including Salmonella typhimurium and enteritidis, which cause gastroenteritis and focal infections. Prior to 1983 it was believed that these were separate species, hence they each have species names. We now know that these are all part of one species. They are classified as serologic variants based on their antigen variation in lipopolysaccharide and flagella. Though technically incorrect, clinically the species names are still widely used.

For typhoid fever, the typical therapy for susceptible strains is an oral fluoroquinolone (ciprofloxicin 500mg or ofloxicin 400mg bid for 5-7 days). Nalidixic resistance has been used as a marker for fluoroquinolone resistance, and higher dose treatment with ciprofloxicin 750mg bid has been successful for these strains. Recently, small numbers of nalidixic acid susceptible, fluoroquinolone resistant strains have been isolated from Africa and Asia, making specific testing for fluoroquinolone resistance essential.

A reasonable alternative therapy is oral azithromycin: 1g every day for 5 days or 1g day 1 followed by 6 days of 500mg.

Ceftriaxone, cefotaxime, and oral cefixime are also alternatives.

Despite susceptibility testing that indicates that S. typhi are susceptible to aminoglycosides and first and second generation cephalosporins, these antibiotics are clinically ineffective and should not be used.

Other alternative therapies for susceptible strains include ampicillin 1g qid, amoxicillin 1g TID, chloramphenicol 500mg qid, and trimethoprim-sulfamethoxazole 1 double strength tablet BID for 14-21 days. These agents are inexpensive, but antibiotic resistance and availability limits their use (oral chloramphenicol is not available in the United States).

Patients with persistent nausea, vomiting, diarrhea, or altered mental status should be treated with parenteral therapy with a third-generation cephalosporin or fluoroquinolone for at least 10 days or 5 days after fever is resolved.

High dose dexamethasone therapy (initial dose 3mg/kg followed by 1mg/kg every 6 hours for 48 hours) should be considered for individuals with shock, obtundation, stupor, or coma.

Chronic carriage of S. typhi can be treated with 4-6 weeks of an antibiotic. Antibiotic therapy includes treatment with oral amoxicillin, trimethoprim-sulfamethoxazole, ciprofloxacin, or norfloxacin. Removal of anatomic abnormalities, such as gallstones or kidney stones combined with antibiotic therapy may be required in the less than 20% who fail to have eradication with antibiotic therapy alone.

Non-typhoidal Salmonella gastroenteritis is usually self-limited and does not require antibiotic therapy; fluid and electrolyte replacement should be administered. Antimicrobial therapy to prevent bacteremia, which occurs in less than 5% of patients, should be considered for those younger than 3 months of age, those older than 50 years of age who have atherosclerosis because of the risk for endovascular infection, those with prosthetic devices, immunosuppression, arthritis, or other endovascular abnormalities. Such prophylaxis should be continued only during the period a patient with Salmonella gastroenteritis is febrile. Non-typhoidal Salmonella bacteremia requires parenteral therapy and a search for endovascular infection. Individuals with HIV and a first episode of bacteremia should be treated with oral therapy for 6 weeks.

Salmonella typhi and paratyphi can only infect humans and, therefore, can be acquired only from ill individuals or chronic carriers who fecally contaminate food or water. In the United States, all cases are from travelers or outbreaks related to chronic carriers. The greatest risk is in travelers to South-central and Southeast Asia that have the highest incidence of typhoid fever, although Mexico and Haiti represent significant risk. The incidence in the United States is low, with less than 500 cases per year. In contrast, worldwide estimates are approximately 27 million cases of typhoid and paratyphoid fever worldwide. The incidence of typhoid fever increases with poor sanitation and lack of access to quality water supplies. The incidence is greater in endemic regions in children and young adults.

The incidence of non-typhoidal Salmonella infections continues to increase worldwide and has doubled during the last 2 decades in the United States. Non-typhoidal Salmonella, of which there are more than 2,000 serotypes, colonize many animals and can be acquired from many food sources, including meat, eggs, poultry, and a variety of fresh and processed foods. Recent outbreaks have included fresh vegetables, frozen dinners, dairy products, peanut butter, and orange juice. The second most common serotype, Salmonella enteritidis, can colonize and penetrate into the developing chicken oviduct and, hence, can be present in the egg yolk of fresh eggs, leading to recommendations to completely cook eggs.

Hospitalized patients should be maintained on enteric precautions. Transmission to healthcare workers is unusual and low risk, although outbreaks have been reported to be related to contaminated bed linens, noncompliance with barrier precautions, and fecally incontinent institutionalized individuals.

Theoretically, with proper dietary precautions, typhoid can be prevented in most travelers. Vaccination is recommended for those traveling to endemic areas at high risk for typhoid fever, including South-central and Southeast Asia, South America, Latin America, Africa, and the Caribbean. Vaccination is not a substitute for good dietary practice, as vaccinated individuals can contract the disease. Two vaccines are commercially available, an oral and a parenteral vaccine are also available. Ty21a is an oral attenuated live vaccine given on sequential days in four doses with a booster after 5 years. It is contraindicated in pregnant women, the immunosuppressed, those on antibiotic therapy, and those younger than 6 years of age. The parenteral Vi polysaccharide vaccine is given IM with a booster every 2 years and is not administered to those younger than 2 years of age because of poor response to this type of vaccine.

Anti-infective prophylaxis is not recommended.

Both humoral- and cell-mediated immunity are required for protection against Salmonella. Humans with deficiencies in interferon-gamma and IL-12 receptor pathways are particularly susceptible to non-typhoidal Salmonellae. Those who have HIV, have received a transplant, or have a lymphoproliferative disease have increased susceptibility to Salmonellae.

HIV-infected individuals, those with low stomach acidity, including those on antacids, residents of nursing homes, neonates, those treated with TNF-alpha antagonists, persons with sickle cell disease (osteomyelitis is a one manifestation), patients who have lymphoproliferative diseases, and transplant recipients are at higher risk. Also, those with underlying TNF/IL-12 receptor defects and neutrophil defects are more susceptible.

In non-typhoidal salmonellosis, there is acute neutrophil infiltration of the bowel. This is absent in typhoid fever, and, instead, one sees enlargement of the Peyer’s Patches and recruitment of macrophages and monocytes with lymphoid enlargement and proliferation.

Salmonella typhi and paratyphi cause enteric fever, a syndrome associated with fever and abdominal pain. Non-typhoidal Salmonella cause gastroenteritis. Approximately 5% of patients with gastroenteritis develop bacteremia, which can lead to focal infections, particularly endovascular infections in those with atherosclerotic cardiovascular disease.

Typhoidal infections can be associated with relapse. The most common complications are intestinal bleeding and perforation. Neurological complications can occur because of meningitis and other poorly understood central nervous system (CNS) phenomena.

Non-typhoidal Salmonella can cause dehydration, and toxic megacolon is a rare complication. Focal infections of the endovascular tissues can result in acute rupture and bleeding.

Typhoid fever is diagnosed by culture of blood, bone marrow, stool, or intestinal secretions. The sensitivity of blood culture alone is low (40-80%). Culture of buffy coat or the lysis centrifugation method for culturing blood can improve sensitivity. Bone-marrow culture and examination should be performed if the diagnosis is strongly suspected. The duodenal string test is also another non-invasive culture method for isolation of S. typhi. Stool cultures in children have higher sensitivity for culture of S. typhi (60%) versus adults (27%). A number of serologic tests for S. typhi have been developed, among which the most widely used is the Widal test, but it is neither sensitive nor specific and is not recommended.

Non-typhoidal gastroenteritis is diagnosed by stool culture. Bacteremia and focal infections are diagnosed by blood cultures or direct culture of infected tissue.

Salmonellae are Gram-negative bacilli that measure 2-3 by 0.4-0.6 uM in size. They are motile and have typical Enterobacteriaceae characteristics, including fermentation of glucose, reduction of nitrates, and do not produce cytochrome oxidase.

Freshly passed stool can be cultured on low selectivity agar medium (MacConkey, deoxycholate) and intermediate selectivity medium (Salmonella-Shigella, xylose-lysine-deoxycholate, or Hektoen) used to screen for enteric pathogens. Increasingly, laboratories use selective chromogenic medium, such as CHROMagar, for primary isolation. In the case of low numbers of organisms, enrichment using tetrathionate and selenite enrichment broths can be used. The organisms can be detected on semi-selective media, such as MacConkey agar, which colorimetrically identify lactose fermentation. Less than 1% of Salmonellae ferment lactose. The differential metabolism of sugars can be used to distinguish Salmonellae serotypes. S. typhi is the only organism that does not produce gas on sugar fermentation. Commercially available polyvalent antisera can be used to identify common serotypes or groups. Because the organism is reportable to public health authorities, it can then be sent to a reference lab for further identification.

There are polymerase chain reaction (PCR)-based tests, and some are commercially available; however, none have currently replaced culture methods, and the clinical sensitivity and specificity are not known.

The pathogen uses intracellular entrance, survival, and replication within the phagosome as a virulence strategy. The replication of bacteria allows innate immune stimulation that leads to inflammation and disease manifestations. The bacteria sense host environments through specific environmental sensors, remodel their surface to resist innate immune killing, and modify the host through delivery of more than 50 virulence proteins using type III secretion systems, which translocate proteins across host membranes to promote bacterial entrance and phagosome remodeling.

Reorganization of the host cytoskeleton and delivery of specific effector proteins to the cytoplasm in the intestinal tract stimulates inflammatory responses that lead to neutrophil infiltration and diarrhea in the intestinal tract. In typhoidal Salmonella infection, organisms are predominately intracellular, and this allows for a chronic febrile illness that requires antibiotics with intracellular killing capacity to resolve the infection. Relapsing disease may also occur from intracellular foci.

CDC Yellow Book Recommendations for International Travel 2012. 2012. (This is a standard reference from the US Centers for Disease Control and Prevention providing data about health risks for international travelers. It is updated every two years.)

Mandell, GL, Douglas, RG, Bennett, JE, Mandell, Gerald L., Bennett, John E., Dolin, Raphael. Mandell, Douglas, and Bennett’s Principles and Practice of Infectious Diseases. 2009. (This print and online reference manual contains detailed information on the diagnosis, treatment and epidemiology of infectious diseases, and it contains more detail on treatment recommendations in the chapter Salmonella Species, Including Salmonella Typhi, 2887-2903.)

Guerrant, RL, Walker, DH, Weller, PF. “Nontyphoidal Salmonellosis”. Tropical Infectious Diseases: Principles, Pathogens and Practice (Expert Consult – Online and Print). 2011. (Contains sections related to treatment, diagnosis and epidemiology, as well as on prevention of infection by the organism.)

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PATHOGEN SAFETY DATA SHEET - INFECTIOUS SUBSTANCES

NAME: Salmonella enterica spp. (formerly Salmonella choleraesuis)

SYNONYM OR CROSS REFERENCE: Salmonella enterica spp. - Salmonellosis.

Serotype Typhi - Typhoid fever, Enteric fever, Typhus abdominalis, Salmonella enterica serotype Typhi.

Serotype Choleraesuis - Salmonella septicaemia, hog cholera, hog typhoid, Samonella enterica serotype Choleraesuis, salmonellosis.

Serotype Paratyphi - Enteric fever, Paratyphoid fever, Salmonella Paratyphi type A, B and C, Salmonella enterica serotype Paratyphoid A, B and C.

CHARACTERISTICS: Salmonella enterica is one of two Salmonella species (enterica and bongori) and a member of the Enterobacteriaceae family (1, 2). Salmonella enterica spp. is subdivided into 6 subspecies (enterica (I), salamae (II), arizonae (IIIa), diarizonae (IIIb), houtenae (IV) and indica (VI) ). The usual habitat for subspecies enterica (I) is warm-blooded animals (1-3). The usual habitat for subspecies II, IIIa, IIIb, IV and VI is cold-blooded animals and the environment (2). All species of Salmonella can infect humans. Salmonella enterica subspecies enterica has 2610 different serotypes; the most well known being serotypes Typhi, Paratyphi, Enteriditis, Typhimurium and Choleraesuis (1). The serotypes are characterized by three surface antigens: the flagellar “H” antigen, the oligosaccharide “O” antigen and the polysaccharide “Vi” antigen (found in Typhi and Paratyphi serotypes) (4). Salmonella enterica is a facultative anaerobe and is a gram negative, motile and non-sporing rod that is 0.7-1.5 by 2.0-5.0 µm in size (4-6).

PATHOGENICITY/TOXICITY: Salmonella enterica can cause four different clinical manifestations: gastroenteritis, bacteremia, enteric fever, and an asymptomatic carrier state (7) . It is more common in children under the age of 5, adults 20-30 year olds, and patients 70 years or older (7) .

Gastroenteritis: Gastroenteritis or “food poisoning” is usually characterized by sudden nausea, vomiting, abdominal cramps, diarrhea, headache chills and fever up to 39 ºC (6-9). The symptoms can be mild to severe and may last between 5-7 days (7, 8). The Typhimurium serotype is the most common cause of gastroenteritis and there are an estimated 1.3 billion cases and 3 million deaths annually (1.4 million cases and 600 deaths in the US alone) due to non-typhoidal Salmonella (2, 9, 10). In well resourced countries with low levels of invasive complications, the mortality rate due to non-typhoidal Salmonella is lower then 1% (10); however, in developing countries, the mortality rate can be as high as 24% (10).

Bacteremia: Bacteremia occurs in 3-10% of individuals infected with Salmonella enterica and certain serotypes (particularly serotype Choleraesuis) have higher mortality rates (4, 11). Immunosuppressed individuals and patients with comorbid medical conditions (e.g. HIV-AIDS, diabetes, mellitus, malignancy, corrhosis, chronic granulomatous disease, sickle cell disease, lymphoproliferative disease, or collagen vascular disease) have a higher risk of developing bacteremia due to a Salmonella infection (4, 7). Bacteremia can cause septic shock; endocarditis, especially in patients older then 50 or with heart conditions; infection of the aorta, especially in patients with pre-existing atherosclerotic disease; liver, spleen, and biliary tract infections in patients with underlying structural abnormalities; mesenteric lymphadenitis; osteomyelitis in long bones and vertebrae; urinary tract infection; pneumonia; pulmonary abscess; brain abscess; subdural and epidural empyema; meningitis; CNS infections (rarely); and death (4, 7).

Enteric fever: Also known as typhoid fever, this infection is caused by serotypes Typhi and Paratyphi (7, 12). Enteric fever is characterized by fever (rising within 72 hours after the onset of illness) and headache, brachycardia, faint rose-colored rash on the abdomen and chest, anorexia, abdominal pain, myalgias, malaise, diarrhea (more common in children) or constipation (more common in adults), hepatosplenomegaly, segmental ileus, meningismus, and neuropsychiatric manifestations (4, 7). Less common symptoms are sore throat, cough, and bloody diarrhoea (4). Complications include myocarditis, encephalopathy, intravascular coagulation, infections of the biliary tree and intestinal tract, urinary tract infection, and metastatic lesions in bone, joints, liver, and meninges (7, 8). The most severe complication (occurs in about 3% of patients) is haemorrhage due to perforations of the terminal ileum of proximal colon walls (4, 7). If untreated, the fever can last for weeks; however, with proper antimicrobial therapy, patients usually recover within 10-14 days (7). The disease is milder in children and, if treated, has a mortality rate of less then 1%; untreated cases can have a mortality rate greater then 10 % (2, 4).

EPIDEMIOLOGY: Infections with Salmonella enterica occur worldwide; however, certain diseases are more prevalent in different regions. Non-typhoid salmonellosis is more common in industrialized countries whereas enteric fever is mostly found in developing countries (with the most cases in Asia) (4, 12). There are about 1.3 billion cases of non-typhoid salmonellosis worldwide each year and the WHO estimates that there are 17 million cases and over 500,000 deaths each year caused by typhoid fever (4, 10). There is a peak in disease in the summer and fall, and it is most common in children (2, 7, 9). In the developing world, salmonellosis contributes to childhood diarrhoea morbidity and mortality as bacteria are responsible for about 20% of cases (4, 13). Epidemics of salmonellosis have been reported in institutions such as hospitals and nursing homes (7).

HOST RANGE: For serotypes causing non-typhoidal salmonellosis, the primary hosts are domestic and wild animals such as cattle, swine, poultry, wild birds, and pets (particularly reptiles) as well as flies (8, 14, 15) . Humans are usually the final host (8) . For Salmonella Typhi, humans are the only known host (7) .

INFECTIOUS DOSE: The infectious dose varies with the serotype. For non-typhoidal salmonellosis, the infectious dose is approximately 10 3 bacilli (4, 7) . For enteric fever, the infectious dose is about 10 5 bacilli by ingestion (4, 6, 7) . Patients with achlorhydria, depressed cell-mediated immunity, or who are elderly may become infected with at a lower infectious dose (4, 7) . The infectious dose may also be dependent on the level of acidity in the patient’s stomach (4) .

MODE OF TRANSMISSION: Human infection usually occurs when consuming contaminated foods and water, contact with infected feces, as well as contact with infective animals, animal feed, or humans (2, 4, 7, 8, 16) . Foods that pose a higher risk include meat, poultry, milk products, and egg products (7-9) . In hospitals, the bacteria have been spread by personnel in pediatric wards, either on their hands or on inadequately disinfected scopes (5, 17) . Flies can infect foods which can also be a risk for transmission to humans (18, 19) .

INCUBATION PERIOD: For non-typhoidal salmonellosis, the incubation period is variable, depends on the inoculum size, and usually ranges between 5 and 72 hours (8) . For typhoid fever, the incubation period can be between 3 and 60 days, although most infections occur 7-14 days after contamination (4) . The incubation period for typhoid fever is highly variable and depends on inoculum size, host susceptibility, and the bacterial strain (2, 4) .

COMMUNICABILITY: Humans can spread the disease for as long as they shed the bacterium in their feces (20) . Certain carriers shed the bacteria for years and 5 % of patients recovering from non-typhoidal salmonellosis can shed the bacteria for 20 weeks (7) . Animals can have a latent or carrier state where they excrete the organism briefly, intermittently or persistently (4) .

RESERVOIR: For non-typhoidal salmonellosis, the reservoir hosts are domestic and wild animals such as cattle, swine, poultry, wild birds, flies and pets (particularly reptiles), as well as other humans (with the chronic carrier state) (7, 8, 14, 18) . For serotype Typhi, humans with the chronic carrier state are the only reservoir for the disease (7, 14) .

ZOONOSIS: Yes. Transmission between animals and humans occur when humans are in contact with infective animals and their feces (2, 8) .

VECTORS: Flies are a possible indirect vector as they may transmit the bacterium to foods (19) .

DRUG SUSCEPTIBILITY: Susceptible to chloramphenicol, ciproflaxin, amoxicillin, co-trimoxazole, trimethprim-sulfonamid, cephalosporins and norfloxacin (4, 8) . Some resistance to chloramphenicol has been reported and, in 1989, 32% of strains were multi-drug resistant (2, 4, 17) .

SUSCEPTIBILITY TO DISINFECTANTS: Gram negative bacteria are susceptible to 2-5% phenol, 1% sodium hypochlorite, 4% formaldehyde, 2% glutaraldehyde, 70% ethanol, 70% propanol, 2% peracetic acid, 3-6% hydrogen peroxide, quaternary ammonium compounds and iodophors; however, Salmonella spp. is resistant to nitrites (6, 17).

PHYSICAL INACTIVATION: Susceptible to moist heat (121 ºC for at least 15 minutes) and dry heat (170 ºC for at least 1 hour) (17) . Salmonella spp. can also be disinfected with ozone (17) .

SURVIVAL OUTSIDE HOST: Serotype Choleraesuis can survive in wet swine feces for at least 3 months and in dry swine feces for at least 13 months (21) . Serotype Dublin can survive in feces spread on concrete, rubber, and polyester for almost six years (17) . Serotype Typhimurium can survive in cattle slurry for 19-60 days, cattle manure for 48 days, soil for 231 days, and water for up to 152 days (22, 23) . Flies have been shown to excrete certain serotypes for 8 days and bed bugs can excrete bacilli for up to 21 days (15, 24) . Certain serotypes have been shown to survive on fingertips for up to 80 minutes, depending on the inoculum size (25) . Salmonella serotypes have been found to live up to 63 days on lettuce, 231 days on parsley, 32 weeks in pecans, 10 months on refrigerated cheddar cheese, 9 months in butter, up to 63 days in frozen yogurt, and up to 20 weeks on frozen minced beef and chicken (26-28) .

SURVEILLANCE: Monitor for symptoms. Confirm diagnosis by isolation from stool or blood and by serotyping to identify the serotype (7, 8) .

Note: All diagnostic methods are not necessarily available in all countries.

FIRST AID/TREATMENT: Treatment depends on the clinical symptoms presented by the patient.

Gastrotenteritis: Fluid and electrolyte replacement as well as control of the nausea and vomiting are the usual treatments for these symptoms (7, 8). Antibiotic treatment is not usually used; however, it may be necessary for neonates, children, the elderly, and the immunosuppressed, in which case ciproflaxin, co-trimoxazole, ampicillin, and cephalosporins may be used (4, 7, 8).

Bacteremia: Antibiotic treatment is used to treat bacteremia (e.g. ciproflaxin, co-trimoxazole, ampicillin, or cephalosporins), especially for neonates, children, the elderly, and the immunosuppressed (7, 8) .

Enteric fever: Chloramphenicol is the most common antibiotic used for enteric fever although ampicillin, trimethoprim-sulfonamid, cephalosporins, ciproflaxin, and norfloxacin are also being used to treat the disease (4, 7) .

Asymptomatic carrier state: Carriers can be treated with ciproflaxin in order to reduce the spread of the infectious agent (8) .

IMMUNIZATION: There is no vaccine to prevent non-typhoidal salmonellosis currently available (14). Three vaccines (2 parenteral and 1 oral) are licensed for use in the US and should be considered for those working with serotype Typhi in a laboratory setting and for travellers who are going to spend extended periods of time in endemic areas (4, 7, 14). The vaccines available offer moderate protection against typhoid fever; however, they do not protect against the Paratyphi serotype of the bacterium (12). It has been shown that a live oral vaccine protects 70% of children inoculated in endemic areas (7). Vaccination is not recommended for pregnant women and patients with HIV-AIDS (29).

PROPHYLAXIS: Antibiotics can be used as prophylaxis in at-risk individuals (for example neonates and the immunocompromised) (7) . Clean water supplies, sanitation, and treatment of carriers are the best prophylactic measures to prevent the spread of enteric fever in endemic areas (7) .

LABORATORY-ACQUIRED INFECTIONS: Until 1974, 258 cases and 20 deaths due to laboratory-acquired typhoid fever were reported (6) . 48 cases of salmonellosis were reported until 1976 (2) . 64 cases and 2 deaths due to Salmonella spp. infections were reported between 1979 and 2004, most of them associated with S. Typhi (30) .

SOURCES/SPECIMENS: All Salmonella enterica subspecies (with the exception of serotype Typhi) are found in blood, urine, feces, food and feed and environmental materials (14) . Serotype Typhi is found in blood, urine, feces and bile (14) .

PRIMARY HAZARDS: Primary hazards when working with Salmonella enterica are accidental parenteral inoculation and ingestion (14) . The risk associated with aerosol exposure is not yet known (14) .

SPECIAL HAZARDS: Infected animals are a risk (for all serotypes except Typhi and Paratyphi) (14) .

RISK GROUP CLASSIFICATION: Risk group 2 (31) . The risk group associated with Salmonella enterica ssp. reflects the species as a whole, but does not necessarily reflect the risk group classification of every subspecies.

CONTAINMENT REQUIREMENTS: Containment level 2 practices, safety equipment and facilities are recommended for work involving infectious or potentially infectious materials, animals, or cultures. Containment level 3 practices and procedures are recommended for activities with serotype typhi that might generate aerosols or large quantities of organisms. These containment requirements apply to the species as a whole, and may not apply to each subspecies within the species.

PROTECTIVE CLOTHING: Lab coat. Gloves when direct skin contact with infected materials or animals is unavoidable. Eye protection must be used where there is a known or potential risk of exposure to splashes (32) .

SPILLS: Allow aerosols to settle, then, wearing protective clothing, gently cover the spill with absorbent paper towel and apply appropriate disinfectant, starting at the perimeter and working towards the center. Allow sufficient contact time before starting the clean up (32) .

DISPOSAL: All wastes should be decontaminated before disposal either by steam sterilization, incineration or chemical disinfection (32) .

STORAGE: The infectious agent should be stored in a sealed and identified container (32) .

REGULATORY INFORMATION: The import, transport, and use of pathogens in Canada is regulated under many regulatory bodies, including the Public Health Agency of Canada, Health Canada, Canadian Food Inspection Agency, Environment Canada, and Transport Canada. Users are responsible for ensuring they are compliant with all relevant acts, regulations, guidelines, and standards.

UPDATED: August 2010

PREPARED BY: Pathogen Regulation Directorate, Public Health Agency of Canada.

Although the information, opinions and recommendations contained in this Pathogen Safety Data Sheet are compiled from sources believed to be reliable, we accept no responsibility for the accuracy, sufficiency, or reliability or for any loss or injury resulting from the use of the information. Newly discovered hazards are frequent and this information may not be completely up to date.