Salmonella Biofilms
Salmonella Biofilms: From food to human disease
from Robert W. Crawford, Geoffrey Gonzalez-Escobedo and John S. Gunn writing in Salmonella: From Genome to Function
Bacterial biofilms are increasingly implicated as burdens to food and public safety. Over the past few decades, we have learned that this sessile environment provides diverse species of bacteria selective advantages in natural, medical, and industrial ecosystems, as well as resistance to commonly administered antibiotics and protection from host immune responses during chronic infection of humans and animals. Salmonella spp. are food-borne pathogens that remain a critical health concern in impoverished and industrialized nations. In the laboratory, salmonellae have been shown to form biofilms on a variety of surfaces. These Salmonella spp. biofilms have been found to contaminate plant and animal food sources to cause human disease upon consumption, and/or to enhance salmonellae colonization of and persistence at sites of infection.
Further reading: Salmonella: From Genome to Function
from Robert W. Crawford, Geoffrey Gonzalez-Escobedo and John S. Gunn writing in Salmonella: From Genome to Function
Bacterial biofilms are increasingly implicated as burdens to food and public safety. Over the past few decades, we have learned that this sessile environment provides diverse species of bacteria selective advantages in natural, medical, and industrial ecosystems, as well as resistance to commonly administered antibiotics and protection from host immune responses during chronic infection of humans and animals. Salmonella spp. are food-borne pathogens that remain a critical health concern in impoverished and industrialized nations. In the laboratory, salmonellae have been shown to form biofilms on a variety of surfaces. These Salmonella spp. biofilms have been found to contaminate plant and animal food sources to cause human disease upon consumption, and/or to enhance salmonellae colonization of and persistence at sites of infection.
Further reading: Salmonella: From Genome to Function
Salmonella evolution
Evolutionary trends associated with niche specialization as modeled by whole genome analysis of egg-contaminating Salmonella enterica serovar Enteritidis
from Jean Guard, Devendra Shah, Cesar A. Morales and Doug Call writing in Salmonella: From Genome to Function
The mosaic nature of the Salmonella enterica genome facilitates its access to multiple environments. Many large scale genomic events have been described that contribute to the combinatorial complexity of the pathogenic Salmonellae. However, the impact of small scale genetic change occurring at the level of single nucleotide polymorphism (SNP) on the emergence of niche specialization is just now becoming appreciated. A recent review describes concepts behind the evolution that culminated in the remarkable ability of Salmonella enterica serovar Enteritidis to contaminate and survive in the internal content of eggs produced by otherwise healthy hens. Evidence suggests that combinations of SNPs facilitate niche specialization by Salmonella enterica. However, few typing methods incorporate unbiased strategies for their detection. Selection of appropriate biological assays for ranking SNPs and combinations of SNPs for their impact on the ability of Salmonella enterica to propagate outbreaks, pandemics and disease will be a significant challenge to improve the safety of the food supply.
Further reading: Salmonella: From Genome to Function
from Jean Guard, Devendra Shah, Cesar A. Morales and Doug Call writing in Salmonella: From Genome to Function
The mosaic nature of the Salmonella enterica genome facilitates its access to multiple environments. Many large scale genomic events have been described that contribute to the combinatorial complexity of the pathogenic Salmonellae. However, the impact of small scale genetic change occurring at the level of single nucleotide polymorphism (SNP) on the emergence of niche specialization is just now becoming appreciated. A recent review describes concepts behind the evolution that culminated in the remarkable ability of Salmonella enterica serovar Enteritidis to contaminate and survive in the internal content of eggs produced by otherwise healthy hens. Evidence suggests that combinations of SNPs facilitate niche specialization by Salmonella enterica. However, few typing methods incorporate unbiased strategies for their detection. Selection of appropriate biological assays for ranking SNPs and combinations of SNPs for their impact on the ability of Salmonella enterica to propagate outbreaks, pandemics and disease will be a significant challenge to improve the safety of the food supply.
Further reading: Salmonella: From Genome to Function
Salmonella classification
New approaches in sub-species level Salmonella classification
from Burkhard Malorny, Elisabeth Hauser and Ralf Dieckmann writing in Salmonella: From Genome to Function:
Salmonellae form a complex group of bacteria consisting of two species, 6 subspecies and more than 2,500 serovars (serotypes). Salmonella identification below species level is most often limited to phenotypic typing methods such as biochemical and serological identification, which are costly, time-consuming and do not always reflect the evolution of Salmonella groups. Newer methods for Salmonella typing and subtyping include genome-based methods such as pulsed field gel electrophoresis (PFGE), Multiple Loci VNTR Analysis (MLVA), Multilocus sequence typing (MLST) and (multiplex-) PCR-based methods. In the last years further molecular typing technologies were evaluated for this purpose. A recent review discusses some of these emerging technologies and gives an outlook on future developments with a focus on oligonucleotide microarrays, spectroscopic methods such as MALDI-TOF mass spectrometry and special developments such as bead-based suspension arrays using Luminex technology and DNA sequence-based approaches. These new techniques promise significant advantages compared to traditional culture-based methods with respect to speed, ease of use, reliability and automation.
Further reading: Salmonella: From Genome to Function
from Burkhard Malorny, Elisabeth Hauser and Ralf Dieckmann writing in Salmonella: From Genome to Function:
Salmonellae form a complex group of bacteria consisting of two species, 6 subspecies and more than 2,500 serovars (serotypes). Salmonella identification below species level is most often limited to phenotypic typing methods such as biochemical and serological identification, which are costly, time-consuming and do not always reflect the evolution of Salmonella groups. Newer methods for Salmonella typing and subtyping include genome-based methods such as pulsed field gel electrophoresis (PFGE), Multiple Loci VNTR Analysis (MLVA), Multilocus sequence typing (MLST) and (multiplex-) PCR-based methods. In the last years further molecular typing technologies were evaluated for this purpose. A recent review discusses some of these emerging technologies and gives an outlook on future developments with a focus on oligonucleotide microarrays, spectroscopic methods such as MALDI-TOF mass spectrometry and special developments such as bead-based suspension arrays using Luminex technology and DNA sequence-based approaches. These new techniques promise significant advantages compared to traditional culture-based methods with respect to speed, ease of use, reliability and automation.
Further reading: Salmonella: From Genome to Function