Salmonellosis Overview

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Questions and Answers

Which serotypes of Salmonella are restricted to human hosts?

Salmonella Gallinarum and Salmonella Pullorum

Salmonella Typhi and Salmonella Paratyphi (correct)

Salmonella Heidelberg and Salmonella Newport

Salmonella Enteritidis and Salmonella Typhimurium

What is the primary disease caused by nontyphoidal serotypes of Salmonella in humans?

Urinary Tract Infection

Meningitis

Pneumonia

Gastroenteritis (correct)

How are Salmonella serotypes primarily classified?

According to the somatic O antigen, surface Vi antigen, and flagellar H antigen (correct)

Based solely on their motility

Through their ability to ferment lactose

By their growth in different pH environments

What is the characteristic morphology of Salmonella bacteria?

Gram-negative, non-spore-forming bacilli Signup and view all the answers

What distinguishes the growth characteristics of Salmonella in laboratory settings?

They produce acid on glucose fermentation and reduce nitrates. Signup and view all the answers

Which statement is true about lactose fermentation among clinical isolates of Salmonella?

Only 1% of clinical isolates are lactose fermenters. Signup and view all the answers

What feature is true for Salmonella except for Salmonella Gallinarum and Salmonella Pullorum?

They are motile by means of peritrichous flagella. Signup and view all the answers

What is the total number of serotypes classified under the genus Salmonella?

Over 2500 Signup and view all the answers

What is the main method used by most laboratories to identify Salmonella serogroups?

Simple agglutination reactions Signup and view all the answers

Which serogroups are responsible for approximately 99% of Salmonella infections in humans?

A, B, C, D, E, Cl Signup and view all the answers

What factors contribute to the variation in the incidence of enteric fever?

Level of urbanization and sanitation conditions Signup and view all the answers

What is a key determinant of the incubation period and disease severity in Salmonella infections?

Ingested dose of organisms Signup and view all the answers

Which risk factor is associated with a higher likelihood of getting enteric fever?

Consumption of raw fruits and vegetables from sewage-treated fields Signup and view all the answers

What types of antibiotics are associated with multidrug-resistant strains of S.Typhi?

Chloramphenicol, ampicillin, trimethoprim Signup and view all the answers

Where is the incidence of paratyphoid fever observed to increase significantly?

India Signup and view all the answers

What is the infectious dose range for Salmonella to cause an infection?

200 to 10,000 CFU Signup and view all the answers

What type of strains have emerged in S.Typhi and S.Paratyphi due to increased fluoroquinolone use?

Strains with decreased susceptibility to ciprofloxacin Signup and view all the answers

Which strain is specifically associated with clinical failure of quinolone treatment?

Clone H.58 Signup and view all the answers

What percentage of travelers diagnosed with enteric fever had received the S.Typhi vaccine?

6% Signup and view all the answers

What is the percentage of recent S.Typhi isolates in the United States that are resistant to ampicillin, chloramphenicol, and TMP-SMX?

15% Signup and view all the answers

Which of the following statements regarding the clinical course of enteric fever is true?

Fever is present in more than 75% of cases. Signup and view all the answers

What has been the predominant demographic for S.Typhi-related enteric fever cases in the United States?

Young to middle-aged adults Signup and view all the answers

What is the main reason for the emergence of strains producing extended-spectrum β-lactamases?

Increased use of specific antibiotics Signup and view all the answers

What term best describes enteric fever based on its hallmark features?

Misnomer due to variable symptoms Signup and view all the answers

Study Notes

Salmonellosis

Salmonella is a genus of gram-negative bacteria that causes a wide range of diseases in humans and animals.
There are >2500 serotypes of Salmonella, with most of them being pathogenic to humans.
The majority of these serotypes cause gastroenteritis, but some can also cause localized infections and bacteremia.
Salmonella enterica subspecies enterica is responsible for most human salmonellosis cases.
The classification of Salmonella serotypes is based on surface antigens, including somatic O antigens, Vi antigens, and flagellar H antigens.
Salmonellae are facultatively anaerobic bacilli that are typically identified based on their growth characteristics.
All serotypes except for Salmonella Gallinarum-Pullorum are motile, and most produce gas during sugar fermentation.
Only 1% of clinical isolates ferment lactose.
Most Salmonella infections occur due to the ingestion of contaminated food or water.
The infectious dose can vary, with higher doses increasing the severity and incubation period of the infection.
Salmonella infections can spread through contaminated food and water, as well as through contact with infected animals or humans.
Typhoid fever is caused by Salmonella Typhi and is characterized by high fever, abdominal pain, and other symptoms.
Paratyphoid fever is caused by Salmonella Paratyphi and is similar to typhoid fever but is often milder.
Salmonella Typhi and Salmonella Paratyphi are restricted to human hosts.
The incubation period for typhoid and paratyphoid fever is typically 7-14 days.
Typhoid fever is endemic in many developing countries, particularly in regions with poor sanitation and access to clean water.
Typhoid fever is more common in urban areas and among young children and adolescents.
Multidrug-resistant (MDR) strains of Salmonella have emerged, posing a challenge for treatment.
MDR strains are commonly resistant to antibiotics like chloramphenicol, ampicillin, and trimethoprim.
Strains with decreased susceptibility to ciprofloxacin have also emerged, particularly in regions like the Indian subcontinent.
Extended-spectrum beta-lactamase (ESBL)-producing strains of Salmonella have also been identified, primarily in India and Nepal.
Typhoid fever is relatively uncommon in the United States, with most cases associated with recent international travel.
Domestically acquired typhoid cases in the US are often sporadic but can also occur due to contaminated food or carriers.
The clinical presentation of enteric fever can be variable.
Fever and abdominal pain are common symptoms but are not always present, making a high index of suspicion necessary.
The diagnosis of typhoid fever is often made based on clinical presentation, history, and laboratory tests like blood culture.
Treatment for typhoid fever typically involves antibiotics, with the choice of antibiotics depending on the susceptibility of the infecting strains.

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Description

Explore the details of Salmonella, a genus of bacteria responsible for various diseases in humans and animals. This quiz covers the serotypes, pathogenicity, and classification of Salmonella as well as its growth characteristics and infection causes. Test your knowledge on this important topic in microbiology.