Importance of Host Factors in Human Salmonellosis Caused by Multiresistant Strains of Salmonella

Abstract

Antimicrobial resistance patterns of Salmonella isolates from persons in randomly selected urban and rural counties in the United States were examined along with clinical and epidemiological characteristics of the host. Multiresistant strains, isolated from 66 (12.2%) of 542 persons evaluated, were associated with five of 20 variables in univariate analyses: serotype heidelberg, host of Hispanic origin, host exposure to penicillins within four weeks before stool culture, age greater than or equal to 60 years, and regular antacid use. By multiple linear regression, the first three variables were each significantly associated with infections due to multiresistant Salmonella. One or more of the last three variables, thought to be host factors that may promote disease, were present for persons yielding 38% of multiresistant strains but only 12% of sensitive strains (P less than .001). The relatively large proportion of multiresistant Salmonella among isolates from persons with these risk factors suggests that to cause disease, resistant organisms are more dependent than are sensitive organisms on host characteristics.

Host Transmission of Salmonella enterica Serovar Typhimurium Is Controlled by Virulence Factors and Indigenous Intestinal Microbiota

“…Regardless of the source of Salmonella serovar Typhimurium, these results suggest an important role for the intestinal microbiota in regulating the levels and shedding of enteric Salmonella serovar Typhimurium. The data may have some relevance to understanding how antibiotic therapy is a risk factor for the development of salmonellosis (47), gastroenteritis associated with antibiotic-resistant Salmonella serovar Typhimurium (19), and increased transmission of antibioticresistant S. enterica strains in poultry (3). Therefore, alterations in the intestinal microbiota caused by antibiotic use may induce fecal shedding and transmission of enteric pathogens.…”

Public Health Consequences of Use of Antimicrobial Agents in Food Animals in the United States

“…46 Similarly, in studies of sporadic salmonellosis, preceding treatment with an antimicrobial was a risk factor for a resistant infection compared to susceptible infections. 34,37,48 Physicians should be aware that, as foodborne pathogens become increasingly resistant, treating patients with antimicrobials, regardless of the reason, increases the risk for that patient to develop a subsequent infection caused by resistant foodborne bacteria. The public health impact of this potentiation effect is more cases of illness and larger outbreaks.…”

Selective antimicrobial modulation of the intestinal tract by norfloxacin in human volunteers and in gnotobiotic mice associated with a human fecal flora

“…However, final appreciation of changes in colonization resistance during antibiotic treatments will only be possible by observing the actual colonization of patients during clinical trials. Such appreciation is important, because antibiotic treatments are associated with increased susceptibility to intestinal pathogens (16,21) and might be a risk factor associated with antibiotic-resistant gram-negative bacteremia in neutropenic patients. We are grateful to J. P. Craig for the gift of V. cholerae 569B and to F. Denis for the gift of S. flexneri DKR115 and V. parahaemolyticus J525C.…”