non typhoid salmonellosis

Non-Typhoidal Non-Typhoidal SalmonellosisSalmonellosis

Infectious Diseases, AIDS & Clinical Infectious Diseases, AIDS & Clinical Immunology Research Center TbilisiImmunology Research Center Tbilisi

Non-typhoidal Salmonellosis, is one of the most common and widely distributed foodborne diseases, with tens of millions of human cases occurring worldwide every year.

In the United States, the incidence of NTS In the United States, the incidence of NTS infection has doubled in the past 2 decades.infection has doubled in the past 2 decades.

In 2009 there were 14 million cases of NTS.In 2009 there were 14 million cases of NTS.

EtiologyEtiology

Salmonellae are gram negative, non-spore Salmonellae are gram negative, non-spore forming, facultatively anaerobic bacilli.forming, facultatively anaerobic bacilli.

Most commonly non-typhoidal Most commonly non-typhoidal salmonellosis caused by salmonellosis caused by S. typhimuriumS. typhimurium or or S. enteritidis.S. enteritidis.

SalmonellaSalmonella was first discovered in 1884 by was first discovered in 1884 by Dr. DE Salmon.Dr. DE Salmon.

EpidemiologyEpidemiology

The incidence of nontyphoidal salmonellosis The incidence of nontyphoidal salmonellosis (NTS) is highest during the rainy season in (NTS) is highest during the rainy season in tropical climates and during the warmer tropical climates and during the warmer months in temperate climates, coinciding with months in temperate climates, coinciding with the peak in food-borne outbreaks.the peak in food-borne outbreaks.

Rates of morbidity and mortality associated Rates of morbidity and mortality associated with NTS are highest among the elderly, with NTS are highest among the elderly, infants, and immunocompromised individuals.infants, and immunocompromised individuals.

EpidemiologyEpidemiology

Unlike S. typhi and S. paratyphi, whose Unlike S. typhi and S. paratyphi, whose only reservoir is humans, NTS can be only reservoir is humans, NTS can be acquired from multiple animal reservoirs. acquired from multiple animal reservoirs.

Transmission is most commonly Transmission is most commonly associated with animal food products, associated with animal food products, especially eggs, poultry, undercooked especially eggs, poultry, undercooked ground meat, dairy products and fresh ground meat, dairy products and fresh produce contaminated with animal waste.produce contaminated with animal waste.

Prevalence in AnimalsPrevalence in Animals

86%

50%

1-36%2-20%

6%Center for Food Security and Public Health, Center for Food Security and Public Health,

Iowa State University, 2011Iowa State University, 2011

In animals, asymptomatic In animals, asymptomatic SalmonellaSalmonella infections are common.infections are common.

Overall, approximately 1-3% of domestic Overall, approximately 1-3% of domestic animals are thought to carry animals are thought to carry SalmonellaSalmonella spp. but the prevalence can be much spp. but the prevalence can be much higher in some species.higher in some species.

Reptile-associated Salmonella infection Reptile-associated Salmonella infection more commonly leads to hospitalization more commonly leads to hospitalization and more frequently involves infants than and more frequently involves infants than do other Salmonella infections.do other Salmonella infections.

Increasing antibiotic resistance in Increasing antibiotic resistance in NTS species is a global problem NTS species is a global problem and has been linked to the and has been linked to the widespread use of antimicrobial widespread use of antimicrobial agents in food animals.agents in food animals.

Clinical ManifestationsClinical Manifestations

In humans, salmonellosis varies from In humans, salmonellosis varies from a self-limiting gastroenteritis to a self-limiting gastroenteritis to septicemia.septicemia.

– GastroenteritisGastroenteritis– Bacteremia and endovascular Bacteremia and endovascular

infectionsinfections– Localized infectionsLocalized infections

GastroenteritisGastroenteritis

Infection with NTS most often results in Infection with NTS most often results in gastroenteritis indistinguishable from that caused gastroenteritis indistinguishable from that caused by other enteric pathogens.by other enteric pathogens.

Nausea, vomiting and diarrhea occur 6–48 h after Nausea, vomiting and diarrhea occur 6–48 h after the ingestion of contaminated food or water. the ingestion of contaminated food or water.

Patients often experience abdominal cramping Patients often experience abdominal cramping and fever (38–39°C). and fever (38–39°C).

Diarrheal stools are usually loose, Diarrheal stools are usually loose, nonbloody and of moderate volume. nonbloody and of moderate volume.

Rarely, NTS causes pseudoappendicitis or an Rarely, NTS causes pseudoappendicitis or an illness that mimics inflammatory bowel disease.illness that mimics inflammatory bowel disease.


Gastroenteritis caused by NTS is usually Gastroenteritis caused by NTS is usually self-limited. self-limited.

Diarrhea resolves within 3–7 days and Diarrhea resolves within 3–7 days and fever within 72 h. fever within 72 h.

Stool cultures remain positive for 4–5 Stool cultures remain positive for 4–5 weeks after infection and—in rare cases weeks after infection and—in rare cases of chronic carriage (<1%)—for >1 year.of chronic carriage (<1%)—for >1 year.


TreatmentTreatmentAntibiotic treatment usually is not Antibiotic treatment usually is not recommended and may prolong fecal carriage.recommended and may prolong fecal carriage.

Neonates, the elderly, and Neonates, the elderly, and immunosuppressed patients (e.g., transplant immunosuppressed patients (e.g., transplant recipients, HIV-infected persons) with NTS recipients, HIV-infected persons) with NTS gastroenteritis are especially susceptible to gastroenteritis are especially susceptible to dehydration and dissemination and may dehydration and dissemination and may require hospitalization and antibiotic therapy.require hospitalization and antibiotic therapy.

Bacteremia and Bacteremia and endovascular infectionsendovascular infections

Up to 8% of patients with NTS gastroenteritis Up to 8% of patients with NTS gastroenteritis develop bacteremia.develop bacteremia.

of these, 5–10% develop localized infections.of these, 5–10% develop localized infections.

Bacteremia is most common with S. Bacteremia is most common with S. choleraesuis and S. Dublin and among choleraesuis and S. Dublin and among infants, the elderly, and infants, the elderly, and immunocompromised patients.immunocompromised patients.


NTS endovascular infection should be NTS endovascular infection should be suspected in high-grade or persistent suspected in high-grade or persistent bacteremia, especially with preexisting bacteremia, especially with preexisting valvular heart disease, atherosclerotic valvular heart disease, atherosclerotic vascular disease or aortic aneurysm.vascular disease or aortic aneurysm.

Arteritis should be suspected in elderly Arteritis should be suspected in elderly patients with prolonged fever and back, patients with prolonged fever and back, chest, or abdominal pain developing after chest, or abdominal pain developing after an episode of gastroenteritis. an episode of gastroenteritis.


Endocarditis and arteritis are rare (<1% of Endocarditis and arteritis are rare (<1% of cases) but are associated with potentially cases) but are associated with potentially fatal complications, including valve fatal complications, including valve perforation, endomyocardial abscess, perforation, endomyocardial abscess, pericarditis, aneurysm rupture, aortoenteric pericarditis, aneurysm rupture, aortoenteric fistula and vertebral osteomyelitis.fistula and vertebral osteomyelitis.


In some areas of sub-Saharan Africa, NTS In some areas of sub-Saharan Africa, NTS may be among the most common causes—may be among the most common causes—or even the most common cause—of or even the most common cause—of bacteremia in children. bacteremia in children.

NTS bacteremia among these children is NTS bacteremia among these children is not associated with diarrhea and has been not associated with diarrhea and has been associated with nutritional status and HIV associated with nutritional status and HIV infection.infection.

Localized infectionsLocalized infections

Intraabdominal infectionsIntraabdominal infectionsIntraabdominal infections due to NTS are rare Intraabdominal infections due to NTS are rare and usually manifest as hepatic or splenic and usually manifest as hepatic or splenic abscesses or as cholecystitis.abscesses or as cholecystitis.Central nervous system infectionsCentral nervous system infectionsNTS meningitis most commonly develops in NTS meningitis most commonly develops in infants 1–4 months of age.infants 1–4 months of age.Pulmonary infectionsPulmonary infectionsNTS pulmonary infections usually present as NTS pulmonary infections usually present as lobar pneumonia, and complications include lobar pneumonia, and complications include lung bscess, empyema, and bronchopleural lung bscess, empyema, and bronchopleural fistula formation.fistula formation.

Localized infectionsLocalized infections

Urinary and genital tract infectionsUrinary and genital tract infectionsUrinary tract infections caused by NTS present as Urinary tract infections caused by NTS present as either cystitis or pyelonephritis.either cystitis or pyelonephritis.NTS genital infections are rare and include ovarian NTS genital infections are rare and include ovarian and testicular abscesses, prostatitis and and testicular abscesses, prostatitis and epididymitis.epididymitis.Bone, joint, and soft tissue infectionsBone, joint, and soft tissue infectionsSalmonella osteomyelitis most commonly affects Salmonella osteomyelitis most commonly affects the femur, tibia, humerus, or lumbar vertebrae and the femur, tibia, humerus, or lumbar vertebrae and is most often seen in association with sickle cell is most often seen in association with sickle cell disease, hemoglobinopathies, or preexisting bone disease, hemoglobinopathies, or preexisting bone disease (e.g., fractures). disease (e.g., fractures).

DiagnosisDiagnosis

The diagnosis of NTS infection is based The diagnosis of NTS infection is based on isolation of the organism from on isolation of the organism from freshly passed stool or from blood or freshly passed stool or from blood or another ordinarily sterile body fluid.another ordinarily sterile body fluid.

Positive cultures of blood, stool or Positive cultures of blood, stool or other specimens are required for other specimens are required for diagnosis.diagnosis.

TreatmentTreatment Antibiotics should not be used routinely to treat Antibiotics should not be used routinely to treat

uncomplicated NTS gastroenteritis. uncomplicated NTS gastroenteritis.

The symptoms are usually self-limited and the The symptoms are usually self-limited and the duration of fever and diarrhea is not significantly duration of fever and diarrhea is not significantly decreased by antibiotic therapy.decreased by antibiotic therapy.

Antibiotic treatment has been associated with Antibiotic treatment has been associated with increased rates of relapse, prolonged increased rates of relapse, prolonged gastrointestinal carriage and adverse drug reactions.gastrointestinal carriage and adverse drug reactions.

Dehydration should be treated with fluid and Dehydration should be treated with fluid and electrolyte replacement.electrolyte replacement.

Preemptive antibiotic Preemptive antibiotic treatmenttreatment

Preemptive antibiotic treatment should be Preemptive antibiotic treatment should be considered for patients at increased risk for considered for patients at increased risk for invasive NTS infection, including invasive NTS infection, including neonates (probably up to 3 months of age); neonates (probably up to 3 months of age); Persons >50 years of age with suspected Persons >50 years of age with suspected atherosclerosis; atherosclerosis; patients with immunosuppression, cardiac patients with immunosuppression, cardiac valvular or endovascular abnormalities or valvular or endovascular abnormalities or significant joint disease.significant joint disease.

Antibiotic Therapy for Nontyphoidal Antibiotic Therapy for Nontyphoidal Salmonella Infection in AdultsSalmonella Infection in Adults

Indication Agent Dosage (route) Duration, days

Preemptive TreatmentCiprofloxacin 500 mg bid (PO) 2–3

Severe GastroenteritisCiprofloxacin

Trimethoprim-sulfamethoxazole

Amoxicillin

Ceftriaxone

500 mg bid (PO) or 400 mg q12h (IV)

160/800 mg bid (PO)

1 g tid (PO)

1–2 g/d (IV)

3–7


BacteremiaCeftriaxone

Ciprofloxacin

2 g/d (IV)

400 mg q12h (IV), then 500 mg bid (PO)

7–14

Endocarditis or ArteritisCeftriaxone

Ciprofloxacin

Ampicillin

2 g/d (IV)

400 mg q8h (IV), then 750 mg bid (PO)

2 g q4h (IV)

42


Meningitis

Ceftriaxone

Ampicillin

2 g q12 h (IV)

2 g q4h (IV)

14–21

Other Localized Infection

Ceftriaxone

Ciprofloxacin

Ampicillin

2 g/d (IV)

500 mg bid (PO) or 400 mg q12h (IV)

2 g q6h (IV)

14–28

PREVENTION AND CONTROLPREVENTION AND CONTROL monitoring of every step of food production, from monitoring of every step of food production, from

handling of raw animal or plant products to handling of raw animal or plant products to preparation of finished foods. preparation of finished foods.

Contaminated food can be made safe for Contaminated food can be made safe for consumption by pasteurization, irradiation, or proper consumption by pasteurization, irradiation, or proper cooking. cooking.

All cases of NTS infection should be reported to local All cases of NTS infection should be reported to local public health departments.public health departments.

Lastly, the prudent use of antimicrobial agents in Lastly, the prudent use of antimicrobial agents in both humans and animals is needed to limit the both humans and animals is needed to limit the emergence of MDR Salmonella.emergence of MDR Salmonella.

non typhoid salmonellosis

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