Risk Factors for Contracting Salmonella Infection in Infants
Jones TF, Ingram LA, Fullerton KE, et al.
Pediatrics. 2006;118:2380-2387
The authors conducted this study in order to better describe the risk factors for contracting Salmonella infection in infants, a group at higher risk for invasive Salmonella disease and complications from both invasive and noninvasive Salmonella.
The data were collected from the Foodborne Diseases Active Surveillance Network, a collaborative effort of the Centers for Disease Control and Prevention, the US Food and Drug Administration, and other federal and state agencies. The data were collected in 2002-2004 utilizing population-based methods at 8 sites. The population surveyed included > 400,000 infants. Cases were infants (< 1 year old) with any non-Typhi Salmonella, were symptomatic, and were not known to be chronic carriers of Salmonella. These cases were not part of any investigated outbreak. Appropriate controls were identified from birth records of the respective local areas. Parents provided information by phone surveys to determine risk factors for Salmonella infection and to obtain other data, including demographic information, health information, environmental exposures, etc.
During the study period, there were over 7000 cases of non-Typhi Salmonella in the surveillance regions, with 9.4% of the cases (n = 677) occurring in infants. Fifteen of those cases were excluded for being part of outbreaks or being carriers. The authors were able to collect survey data on 67% of the eligible cases, and those not enrolled were similar to the cases that were enrolled in the study. There were 928 controls. Diarrhea (98%) and fever (73%) were present in a majority of cases, with vomiting being present in 33%. Fatalities were few at 0.5% (n = 2). Ninety-two percent of cases had Salmonella isolated from stool, and 7% had Salmonella bacteremia or meningitis (only 1 case had central nervous system Salmonella).
Numerous factors were associated with increased odds of having Salmonella infections, including attending daycare with another child who had diarrhea (OR 4.4, 95% CI 1.8-10.7), travel outside of the United States (OR 8.9, 95% CI 2.6-30.9), reptile exposure (OR 5.2), consumption of concentrated infant formula (as opposed to ready-mixed, OR 2.0), having ridden in a shopping cart with meat or poultry placed near the infant (OR 3.2), and consumption of any meat (OR 1.7).
Consumption of egg was not associated with Salmonella risk. Conversely, several factors were associated with decreased odds of contracting Salmonella, including breastfed infants (OR 0.5, 95% CI 0.3-0.6) and being able to crawl (OR 0.5). Reptile exposure was the largest contributor to cases, with consuming concentrated infant formula and riding in shopping cart near meat and poultry closely following.
The authors conclude that there are several factors that one can modify to reduce the risk of contracting Salmonella in infants and suggest that these factors could form the basis of interventions to reduce Salmonella infections in high-risk populations.
This article serves as an excellent reminder of risk factors to look for when considering whether an infant with diarrhea is at risk for Salmonella. Because of the nature of the data collection, it's not clear why consumption of concentrated formula (but not powdered) had an increased association with Salmonella, but storage procedures and preparation procedures could both contribute. It's notable that reptile exposure was the factor with the largest contribution to cases, even in this population of infants; it's important to ask about reptiles in the house even if infants are not as likely to play with them as older children.
Abstract
Jones TF, Ingram LA, Fullerton KE, et al.
Pediatrics. 2006;118:2380-2387
The authors conducted this study in order to better describe the risk factors for contracting Salmonella infection in infants, a group at higher risk for invasive Salmonella disease and complications from both invasive and noninvasive Salmonella.
The data were collected from the Foodborne Diseases Active Surveillance Network, a collaborative effort of the Centers for Disease Control and Prevention, the US Food and Drug Administration, and other federal and state agencies. The data were collected in 2002-2004 utilizing population-based methods at 8 sites. The population surveyed included > 400,000 infants. Cases were infants (< 1 year old) with any non-Typhi Salmonella, were symptomatic, and were not known to be chronic carriers of Salmonella. These cases were not part of any investigated outbreak. Appropriate controls were identified from birth records of the respective local areas. Parents provided information by phone surveys to determine risk factors for Salmonella infection and to obtain other data, including demographic information, health information, environmental exposures, etc.
During the study period, there were over 7000 cases of non-Typhi Salmonella in the surveillance regions, with 9.4% of the cases (n = 677) occurring in infants. Fifteen of those cases were excluded for being part of outbreaks or being carriers. The authors were able to collect survey data on 67% of the eligible cases, and those not enrolled were similar to the cases that were enrolled in the study. There were 928 controls. Diarrhea (98%) and fever (73%) were present in a majority of cases, with vomiting being present in 33%. Fatalities were few at 0.5% (n = 2). Ninety-two percent of cases had Salmonella isolated from stool, and 7% had Salmonella bacteremia or meningitis (only 1 case had central nervous system Salmonella).
Numerous factors were associated with increased odds of having Salmonella infections, including attending daycare with another child who had diarrhea (OR 4.4, 95% CI 1.8-10.7), travel outside of the United States (OR 8.9, 95% CI 2.6-30.9), reptile exposure (OR 5.2), consumption of concentrated infant formula (as opposed to ready-mixed, OR 2.0), having ridden in a shopping cart with meat or poultry placed near the infant (OR 3.2), and consumption of any meat (OR 1.7).
Consumption of egg was not associated with Salmonella risk. Conversely, several factors were associated with decreased odds of contracting Salmonella, including breastfed infants (OR 0.5, 95% CI 0.3-0.6) and being able to crawl (OR 0.5). Reptile exposure was the largest contributor to cases, with consuming concentrated infant formula and riding in shopping cart near meat and poultry closely following.
The authors conclude that there are several factors that one can modify to reduce the risk of contracting Salmonella in infants and suggest that these factors could form the basis of interventions to reduce Salmonella infections in high-risk populations.
This article serves as an excellent reminder of risk factors to look for when considering whether an infant with diarrhea is at risk for Salmonella. Because of the nature of the data collection, it's not clear why consumption of concentrated formula (but not powdered) had an increased association with Salmonella, but storage procedures and preparation procedures could both contribute. It's notable that reptile exposure was the factor with the largest contribution to cases, even in this population of infants; it's important to ask about reptiles in the house even if infants are not as likely to play with them as older children.
Abstract