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

The most common symptoms of Salmonella Enteritidis include fever, diarrhea, vomiting, abdominal cramps, muscle aches, and headache. These symptoms generally occur between 12-72 hours after the bacteria has been ingested and last anywhere from 4-7 days. Healthy individuals can usually rid themselves of the bacteria on their own; however, children, elderly people, and those with compromised immune systems may require additional treatment [18].

Once established in the intestine, the bacteria's virulence factors go to work. An enterotoxin results in the release of fluids from the cell into the lumen. This factor is responsible for the diarrhea and vomiting symptoms. Next, the endotoxin results in the release of endogenous pyrogens from the host cell, causing a fever in the victim. Lastly, the cytotoxin is responsible for the disintegration of the cytoplasm.

ampicillin, amoxicillin, ciprofloxacin, or trimethoprim/sulfamethozazole

monella spp. (-) (99)

Salmonella enterica ATCC® 14028 A 24hr 35°C Aerobic Growth; colorless to amber colonies

Salmonella enterica ATCC® 14028 A 24hr 35°C Aerobic Growth; colonies colorless

Temperature Most Salmonella serotypes can grow over the temperature range 7 – 48 ºC, but growth is slow at temperatures below 10 ºC. Reports suggesting that some serotypes can grow at temperatures as low as 4 ºC are not universally accepted. Nevertheless Salmonella is able to survive for extended periods in chilled and frozen foods. The majority of Salmonella serotypes are not particularly heat resistant and are usually killed by pasteurisation processes. D-values are typically 1 – 10 mins at 60 ºC and less than 1 min at 70 ºC, with typical z-values of 4 – 5 ºC. However, there are some important exceptions. Some rare serotypes such as S. Senftenberg are much more heat resistant (approximately 10 – 20 times) than others at high water activities, and some foods with high fat content or low water activity reduce the effectiveness of heat treatments that would normally destroy the cells. pH A few Salmonella serotypes can grow over a range of pH values from 3.7- 9.5 under otherwise ideal conditions, but the optimum is 6.5 – 7.5. Although Salmonella cannot grow under very acid conditions, the cells are able to survive for some time in acid environments. Water activity Salmonellae are not able to grow in dry environments and require water activity values of at least 0.94 to multiply in foods. The cells will die out at lower water activities values, but inactivation can be extremely slow in some products (measured in years), particularly those with very low moisture and high fat content, such as chocolate. Salmonella may also survive for some time on dry food production surfaces. Atmosphere All salmonellae can grow with or without oxygen (facultative anaerobes) and in atmospheres containing high levels of carbon dioxide (possibly up to 80 % in some conditions). Chemicals Salmonella is not especially resistant to sanitisers used in the food industry, but is able to form protective biofilms if cleaning is inadequate.

Salmonella has evolved to live in the gastrointestinal tracts of animals and so the primary sources of contamination are animals and their faeces. Many different animals can be infected with Salmonella, often without suffering from any obvious symptoms. Birds, rodents, reptiles, frogs, fish and snails can all carry the bacteria. This can result in contamination of soil and surface waters, leading to infection of food animals and contamination of fruits and vegetables, herbs, spices, seeds, nuts and shellfish. Food animals can also become infected via their feed or from other infected animals.

Ampicillin is a penicillin beta-lactam antibiotic used in the treatment of bacterial infections caused by susceptible, usually gram-positive, organisms. The name "penicillin" can either refer to several variants of penicillin available, or to the group of antibiotics derived from the penicillins. Ampicillin has in vitro activity against gram-positive and gram-negative aerobic and anaerobic bacteria. The bactericidal activity of Ampicillin results from the inhibition of cell wall synthesis and is mediated through Ampicillin binding to penicillin binding proteins (PBPs). Ampicillin is stable against hydrolysis by a variety of beta-lactamases, including penicillinases, and cephalosporinases and extended spectrum beta-lactamases.Mechanism of actionBy binding to specific penicillin-binding proteins (PBPs) located inside the bacterial cell wall, Ampicillin inhibits the third and last stage of bacterial cell wall synthesis. Cell lysis is then mediated by bacterial cell wall autolytic enzymes such as autolysins; it is possible that Ampicillin interferes with an autolysin inhibitor.

The resistance to Cm is known to be me-diated by the plasmid-located enzymes called chlo-ramphenicol acetyltransferases (CAT) (Cannon et al., 1990), or by the nonenzymatic chloramphenicol resistance gene cmlA (Dorman and Foster, 1982), that encodes an efflux pump.

Table 1

Virulence Factors:

Mechanism of Action Sulfamethoxazole inhibits bacterial synthesis of dihydrofolic acid by competing with paraaminobenzoic acid (PABA). Trimethoprim blocks the production of tetrahydrofolic acid from dihydrofolic acid by binding to and reversibly inhibiting the required enzyme, dihydrofolate reductase. Thus, SEPTRA blocks two consecutive steps in the biosynthesis of nucleic acids and proteins essential to many bacteria. Mechanism of Resistance In vitro studies have shown that bacterial resistance develops more slowly with SEPTRA than with either trimethoprim or sulfamethoxazole alone. SEPTRA has have been shown to be active against most strains of the following microorganisms, both in vitro and in clinical infections as described in the INDICATIONS AND USAGE section.

Salmonella can also actively invade both phagocytic and non-phagocytic cells using a type III secretion system (T3SS), T3SS1.

nternalization into host cells

DNA gyrase has two subunits, which in turn have two subunits each, i.e. 2A and 2B subunits. The A and B subunits together bind to DNA, hydrolyze ATP, and introduce negative supertwists. The A subunit carries out nicking of DNA, B subunit introduces negative supercoils, and then A subunit reseals the strands. Fluoroquinolones bind to the A subunit and interfere with its strand cutting and resealing function.

were recalled due to evidence of Salmonella contamination.[9]

Mechanism Of Action The bactericidal action of ciprofloxacin results from inhibition of the enzymes topoisomerase II (DNA gyrase) and topoisomerase IV (both Type II topoisomerases), which are required for bacterial DNA replication, transcription, repair, and recombination. Mechanism Of Resistance The mechanism of action of fluoroquinolones, including ciprofloxacin, is different from that of penicillins, cephalosporins, aminoglycosides, macrolides, and tetracyclines; therefore, microorganisms resistant to these classes of drugs may be susceptible to ciprofloxacin. Resistance to fluoroquinolones occurs primarily by either mutations in the DNA gyrases, decreased outer membrane permeability, or drug efflux. In vitro resistance to ciprofloxacin develops slowly by multiple step mutations. Resistance to ciprofloxacin due to spontaneous mutations occurs at a general frequency of between < 10-9 to 1x10-6 .

Investigation of the Outbreak

Always wash hands thoroughly with soap and water right after touching livestock, equipment for animals, or anything in the area where animals live and roam. This is especially important to do before preparing or consuming food or drink for yourself or others. Adults should supervise hand washing for young children. Use hand sanitizer if soap and water are not available right away. Use dedicated shoes, work gloves, and clothing that you only use when working with livestock. Keep these items outside of your home. Do not eat or drink in the areas where livestock live and roam. Do not allow toys, pacifiers, spill-proof cups, baby bottles, strollers, or similar items in livestock areas. Wash hands after removing any clothes and shoes you wore while working with livestock. Work with your veterinarian to keep your livestock healthy.

Nalidixic acid resistance was observed in 13.3%

Since 1996, an increasing number of S. Enteritidis isolates submitted to NARMS have been resistant to nalidixic acid

The main habitat where Salmonella is found is in the intestines of animals and humans (figure 4). Typical vectors of Salmonella enterica include chicken including their eggs, swine, dairy and beef cattle, and sometimes even insects, rodents, and other farm animals.

Here, it binds to the wall of the intestine, and through some special proteins that it makes in response to the particular conditions in the intestine it actually penetrates the barrier between us and the outside. Once it has gained access to our insides, it is taken to the liver or spleen. For most other bacteria, this journey would kill them, however Salmonella has evolved mechanisms to prevent our immune system from doing its job efficiently. In the liver, the Salmonella can grow again, and be released back into the intestine. Of course, not all of the Salmonella pass through the intestinal wall, and many of them are expelled from the intestine in the diarrhea. In regions with poor sanitation, these bacteria can than survive in the soil or in rivers and infect the next person, cow, chicken or mouse that comes along.

Salmonella are traced back to dairy, poultry and meat products, but Salmonella can grow on just about any food. Chickens and eggs are particular high risk foods.

binds to the wall of the intestine, and through some special proteins that it makes in response to the particular conditions in the intestine it actually penetrates the barrier between us and the outside. Once it has gained access to our insides, it is taken to the liver or spleen.

Key biochemical tests are fermentation of glucose, negative urease reaction, lysine decarboxylase, negative indole test, H2S production, and fermentation of dulcitol. Serological confirmation tests typically use polyvalent antisera for flagellar (H) and somatic (O) antigens

a pre-enrichment culture in a non-selective liquid medium such as buffered peptone water, incubated at 37oC for 18 hours. Modified pre-enrichment methods may be necessary for samples containing inhibitory compounds. The pre-enrichment culture is then typically subcultured into two different selective enrichment media, such as Rappaport Vasiliadis Soy broth (RVS) and Muller-Kauffmann Tetrathionate-Novobiocin (MKTTn) broth, and incubated for a further 24 hours at 41.5oC (RVS) or 37oC (MKTTn). The selective enrichment culture is usually inoculated on to at least two selective agar media and incubated at 37oC for 24 hours. The ISO method specifies the XLD agar and one optional selective medium. A variety of alternatives are available, including Bismuth Sulphite agar, Brilliant Green agar and Hektoen Enteric agar. A number of selective chromogenic agar media specifically designed for the differentiation of Salmonella colonies are commercially available. Typical Salmonella colonies on selective agar are subcultured onto non-selective media prior to confirmatory testing.

non-spore forming, usually motile rods

blood, urine, feces, food and feed and environmental materials

RESISTANCE OF CONCERN

Background: Salmonella enterica subsp. enterica serovar Poona (antigenic formula 1,13,22:z:1,6:[z44],[z59]) is a serovar of the O:13 (G) serogroup.  This serovar has been isolated from found animal and produce sources.

There were 216 gastroenteritis cases reported from 20 November to 4 December 2007. The causative agent was identified as Salmonella enterica subspecies enterica serotype Enteritidis for 14 out of 20 cases tested. The vehicle of transmission was traced to cream cakes produced by a bakery and sold at its retail outlets (P < 0.001, OR = 143.00, 95% Cl = 27.23–759.10). More than two-thirds of the 40 Salmonella strains isolated from hospitalized cases, food samples and asymptomatic food handlers were of phage type 1; the others reacted but did not conform to any phage type. The phage types correlated well with their unique antibiograms. The ribotype patterns of 22 selected isolates tested were highly similar, indicating genetic relatedness. The dendrogram of the strains from the outbreak showed distinct clustering and correlation compared to the non-outbreak strains, confirming a common source of infection.

Diseases which result from pathogenic microorganisms are of two types: infection and intoxication. Foodborne infection is caused by the ingestion of food containing live bacteria which grow and establish themselves in the human intestinal tract. Foodborne intoxication is caused by ingesting food containing toxins formed by bacteria which resulted from the bacterial growth in the food item. The live microorganism does not have to be consumed.

Growth; red slant, yellow butt, gas positive, black butt (H 2 S produced)

Infection: occurs when live bacterial cells are ingested. These bacterial cells can then grow in the digestive tract and cause symptoms. An example of a bacterial infection is Salmonella infection.

BIOCHEMICAL TESTS

Bismuth sulfite agar: Salmonellae produce black colonies. Blood Agar: S. typhi and S. paratyphi usually produce non-hemolytic smooth white colonies. MacConkey Agar: Non lactose fermenting smooth colonies i.e. pale colonies Deoxycholate Citrate Agar (DCA): Salmonella appear as pale colonies.

Temperature range: 6-46 oC (43-115 oF) Optimum Temperature: 37oC (98.6oF) pH range: 4.1-9.0 Optimum pH: 6.5 - 7.5

Salmonella Enteritidis — the most common Salmonella serotype — accounted for 36 percent of infections resistant to nalidixic acid (resistance to nalidixic acid relates to decreased susceptibility to ciprofloxacin, a widely used fluoroquinolone drug).

Susceptible to chloramphenicol, ciproflaxin, amoxicillin, co-trimoxazole, trimethprim-sulfonamid, cephalosporins and norfloxacin

Specificity of coloration

LIMITATIONS OF THE METHOD

chromID® Salmonella Media

Salmonella ASAP™ Chromogenic Media

chromID® Salmonella Ref 43621 (20 plates) Chromogenic media for the isolation and differentiation of Salmonella Direct from specimen Pink to mauve Click here to view product flyer.Click here for an evaluation sample of this media. chromID® Salmonella/Hektoen bi-plate Ref 43465 (20 bi-plates) Chromogenic media for the isolation and differentiation of Salmonella combined with Hektoen Optimized growth of Salmonella while still providing for the recovery of Shigella and other Gram negative organisms Click here for an evaluation sample of this media.

Salmonellae are capable of producing biofilms providing the organism with an exopolysaccharide matrix that inhibits chemical attack against chlorine [132–134]

Salmonella is considered to be mesophilic with some strains being able to survive at extremely low or high temperatures (2°C to 54°C).

In the US, Salmonella is the leading foodborne pathogen, causing the largest number of deaths and has the highest cost burden [12]. The annual costs associated with salmonellosis for 2010 were estimated at $2.71 billion for 1.4 million cases [13]. The highest numbers of Salmonella outbreaks from the past decade are related to land animals, with poultry as a main reservoir (Table 2). More than 70% of human salmonellosis in the US has been attributed to the consumption of contaminated chicken, turkey, or eggs [14]. From 1998 to 2008, approximately 145 Salmonella outbreaks have been associated with poultry while 117 outbreaks were associated with eggs, causing illnesses in 2580 and 2,938 people, respectively [14].

The main niche of Salmonella serovars is the intestinal tract of humans and farm animals. It can also be present in the intestinal tract of wild birds, reptiles, and occasionally insects. Feedstuff, soil, bedding, litter, and fecal matter are commonly identified as sources of Salmonella contamination in farms [7–10]. As Salmonella colonizes the gastrointestinal tract, the organisms are excreted in feces from which they may be transmitted by insects and other animals to a large number of places and are generally found in polluted water. Salmonellae do not originate in water; therefore their presence denotes fecal contamination [6]. Humans and animals that consume polluted water may shed the bacteria through fecal matter continuing of the cycle of contamination.

Current recommendations are to treat most patients with uncomplicated Salmonella infection with supportive therapy and no antimicrobial agents. Antimicrobial therapy should be considered for patients who are severely ill (for example, those with severe diarrhea, high fever, or manifestations of extraintestinal infection) and for gastroenteritis caused by Salmonella species in people at increased risk of invasive disease (infants aged <3 months, older adults aged ≥60 years, and the debilitated or immunosuppressed). Fluoroquinolones are often employed for empiric treatment of patients with moderate to severe travelers’ diarrhea; azithromycin and rifaximin are also commonly used. Resistance to antimicrobial agents varies by serotype and geographic region. Resistance to older antimicrobial agents (chloramphenicol, ampicillin, and trimethoprim-sulfamethoxazole) has been present for many years, and resistance to both fluoroquinolones and third-generation cephalosporins has increased.

About 90% of isolates are obtained from routine stool culture, but isolates are also obtained from blood, urine, and material from sites of infection. Isolates of salmonellae are needed for serotyping and antimicrobial susceptibility testing.

Gastroenteritis is the most common clinical presentation of nontyphoidal Salmonella infection. The incubation period of nontyphoidal salmonellosis is 6–72 hours, but illness usually occurs within 12–36 hours after exposure. Illness is commonly manifested by acute diarrhea, abdominal pain, fever, and sometimes vomiting. The illness usually lasts 4–7 days, and most people recover without treatment. Approximately 5% of people develop bacteremia or focal infection (such as meningitis or osteomyelitis). Salmonellosis outcomes differ by serotype. Infections with some serotypes, including Dublin and Choleraesuis, are more likely to result in invasive infections. Rates of invasive infections and death are generally higher among infants, older adults, and people with immunosuppressive conditions (including HIV), hemoglobinopathies, and malignant neoplasms.

Nontyphoidal salmonellae are a leading cause of bacterial diarrhea worldwide; they are estimated to cause 94 million cases of gastroenteritis and 115,000 deaths globally each year. The risk of Salmonella infection among travelers returning to the United States varies by region of the world visited. In one analysis, the incidence of laboratory-confirmed infections from 2004 through 2009 was 7.1 cases per 100,000 among travelers to Latin American and Caribbean, 5.8 cases per 100,000 among travelers to Asia, and 25.8 cases per 100,000 among travelers to Africa. The true number of illnesses is much higher, because most ill people do not have a stool specimen tested. Travelers with salmonellosis were most likely to report visiting the following countries: Mexico (38% of travel-associated salmonellosis), India (9%), Jamaica (7%), the Dominican Republic (4%), China (3%), and the Bahamas (2%). Salmonella infection and carriage has been reported among internationally adopted children.

Usually through the consumption of food or water contaminated with animal feces. Transmission can also occur through direct contact with infected animals or their environment and directly between humans.

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).

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).

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).

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).

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).

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).

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).

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).

The usual habitat for subspecies enterica (I) is warm-blooded animals (1-3).

Salmonella enterica causes ≈1 million illnesses and >350 deaths annually in the United States (1). Among >2,500 known serotypes, S. enterica serotype Enteritidis is one of the most commonly reported causes of human salmonellosis in most industrialized countries (2).

Secreted proteins are of major importance for the pathogenesis of infectious diseases caused by Salmonella enterica. A remarkable large number of fimbrial and non-fimbrial adhesins are present in Salmonella, and mediate biofilm formation and contact to host cells. Secreted proteins are also involved in host cell invasion and intracellular proliferation, two hallmarks of Salmonella pathogenesis.[4]