"this book addresses important themes in the molecular epidemiology of bacterial pathogens ... Another consistent strength of this book is the detailed coverage of antibiotic resistance across the entire spectrum of food and waterborne pathogens ... for clinicians, food or environmental scientists, or public health officials interested in gaining a foundation in the molecular microbiology of this important group of pathogens, this book would provide an excellent foundation. Alternatively, for those with expertise in specific organisms, this book provides an interesting look across the spectrum of food and waterborne bacterial pathogens." from Jason B. Harris (Harvard Medical School, Boston, USA) writing in Clin. Inf. Dis. (2013) read more ...

Foodborne and Waterborne Bacterial Pathogens: Epidemiology, Evolution and Molecular Biology Edited by: Shah M. Faruque ISBN: 978-1-908230-06-5 Publisher: Caister Academic Press Publication Date: July 2012 Cover: hardback "an excellent foundation" (Clin. Inf. Dis.)

"well-written and informative chapters on stress systems ... on high scientific level and with extensive references ... chapters of this book are worth reading" from Erhard Bremer (Marburg, Germany) writing in Biospektrum (2013) 19: 107-111 read more ...

Stress Response in Microbiology Edited by: Jose M. Requena ISBN: 978-1-908230-04-1 Publisher: Caister Academic Press Publication Date: June 2012 Cover: hardback "well-written and informative" (Biospektrum)

"useful tables and overviews summarizing the state of knowledge on Salmonella pathogenesis ... great overviews and insights into Salmonella biology and useful frameworks for future studies." from James M. Slauch (University of Illinois, Urbana-Champaign, USA) writing in ASM Microbe (2012) 7: 333-334 read more ...

Salmonella: From Genome to Function Edited by: Steffen Porwollik ISBN: 978-1-904455-73-8 Publisher: Caister Academic Press Publication Date: January 2011 Cover: hardback "great overviews and insights" (ASM Microbe)

"there is a wealth of detailed, up-to-date information on the epidemiology, pathogenesis and molecular biology of these pathogens written by experts in the field. This book would very useful to those studying gastrointestinal bacterial pathogens or food and water microbiology at postgraduate level and as a reference for specialists working in this area." from Kathie Grant (Health Protection Agency, UK) writing in Microbiology Today (2013) read more ...

Foodborne and Waterborne Bacterial Pathogens: Epidemiology, Evolution and Molecular Biology Edited by: Shah M. Faruque ISBN: 978-1-908230-06-5 Publisher: Caister Academic Press Publication Date: July 2012 Cover: hardback "a wealth of detailed, up-to-date information" (Microbiol. Today)

from Riikka Laukkanen-Ninios and Maria Fredriksson-Ahomaa writing in Foodborne and Waterborne Bacterial Pathogens: Epidemiology, Evolution and Molecular Biology:

Enteropathogenic yersiniosis is caused due to foodborne infection with Yersinia enterocolitica and Y. pseudotuberculosis. Several virulence factors have been identified that are common to these two pathogens even though Y. pseudotuberculosis is genetically more related to Y. pestis, which is typically transmitted by fleas and not through foods. Diarrhoea and abdominal pain are the most dominant symptoms for Y. enterocolitica and Y. pseudotuberculosis infections. Occasionally, complications such as joint pain and skin rash may occur, typically among adults. Most human cases are caused by Y. enterocolitica. The reported cases are mainly sporadic and outbreaks are uncommon. However, outbreaks of Y. pseudotuberculosis infection, often in school children, have occurred in Finland, Russia and Japan. The most important transmission route is proposed to be via contaminated foods even though these pathogens have seldom been isolated from foods. The low isolation rates are probably due to the low sensitivity of the culture methods. Y. enterocolitica infections have been linked to raw or under-cooked pork and pork products while Y. pseudotuberculosis infections have been linked to raw fresh produce and surface water. Pigs are so far the most important reservoir for human pathogenic Y. enterocolitica. The principal reservoir of Y. pseudotuberculosis is believed to be wild animals, especially rodents and birds. Transmission routes of these pathogens from animals to humans are mostly unknown.

Further reading: Foodborne and Waterborne Bacterial Pathogens: Epidemiology, Evolution and Molecular Biology

from Sangmi Lee, Robin M. Siletzky and Sophia Kathariou writing in Foodborne and Waterborne Bacterial Pathogens: Epidemiology, Evolution and Molecular Biology:

Listeria monocytogenes is a Gram-positive foodborne pathogen that causes a severe, potentially fatal illness (listeriosis) in animals and humans. The only human pathogen within the genus Listeria, this bacterium is equipped with sophisticated mechanisms to invade mammalian cells and proliferate inracellularly. Population genetics data indicate that some groups of L. monocytogenes are more frequently associated with human listeriosis. However, the ecology and potentially unique characteristics of such groups remain to be elucidated. This review discusses recent advances in the epidemiology of listeriosis and epidemic-associated clonal groups; the characterization of pathogenicity of L. monocytogenes; the evolution of Listeria species and L. monocytogenes; and the increasingly recognized importance of Listeria phages in the ecology of L. monocytogenes in food processing facilities.

Further reading: Foodborne and Waterborne Bacterial Pathogens: Epidemiology, Evolution and Molecular Biology

from T. Ramamurthy and M. John Albert writing in Foodborne and Waterborne Bacterial Pathogens: Epidemiology, Evolution and Molecular Biology:

There are five categories of diarrhoeagenic Escherichia coli (DEC) namely enterotoxigenic, enteropathogenic, enterohaemorrhagic, enteroinvasive and enteroaggregative. They have evolved from nonpathogenic commensal strains by acquisition of specific virulence genes through mobile genetic elements. Their pathogenesis differs and they produce distinct clinical syndromes and pathological lesions and have different epidemiological characteristics. The virulence genes are carried on plasmids, bacteriophages, transposons or pathogenicity islands. DEC produce an array of virulence factors which include colonization factors, enterotoxins, cytotoxins, haemolysins, invasins etc. The diseases they produce range from acute watery diarrhea to dysentery to bloody diarrhoea with haemolytic uraemic syndrome. Even though the major burden of the disease is in the developing world, no part of the world is free from them, and EHEC infections are predominant in developed countries. A variety of molecular tools have been developed to study the diversity and transmission of these pathogens. Even though attempts are being made, no ideal vaccine exists against any category of DEC, therefore maintaining appropriate food and water hygiene are the only ways to keep the infections under control. We must also be on guard against the emergence of new pathogenic strains. The recent emergence of a hybrid enteroaggregative-haemorrhagic E. coli with the rare serotype of O104:H4 in Germany that caused high mortality rates is a case in point.

Further reading: Foodborne and Waterborne Bacterial Pathogens: Epidemiology, Evolution and Molecular Biology

from Marie Yeung and Kathryn J. Boor writing in Foodborne and Waterborne Bacterial Pathogens: Epidemiology, Evolution and Molecular Biology:

As a natural inhabitant of the marine environment, Vibrio parahaemolyticus is frequently present in seafood, and particularly in oysters. V. parahaemolyticus can multiply rapidly under favorable conditions, but also may exist in a viable but non-culturable state under unfavorable conditions. A small subset of this species can cause human disease, with acute gastroenteritis as the predominant clinical manifestation. Two pore-forming hemolysins, thermostable direct hemolysin (TDH) and TDH-related hemolysin (TRH), are recognized as contributors to V. parahaemolyticus pathogenesis. Therefore, many detection methods for pathogenic strains focus on determining the presence of the genes encoding these hemolysins or on detection of beta-hemolysis on Wagatsuma agar (i.e. the Kanagawa Phenomenon). Serotyping and molecular fingerprinting techniques are also used to subtype Vibrio parahaemolyticus isolates. One of the most effective strategies for preventing Vibrio parahaemolyticus infection from consumption of raw or uncooked seafood is to reduce seafood post-harvest storage temperatures to prevent the growth of this species.

Further reading: Foodborne and Waterborne Bacterial Pathogens: Epidemiology, Evolution and Molecular Biology

from Iddya Karunasagar and Anusha Rohit writing in Foodborne and Waterborne Bacterial Pathogens: Epidemiology, Evolution and Molecular Biology:

Vibrio vulnificus is a normal inhabitant of warm estuarine environments all over the world and may be associated with a wide variety of seafood. In susceptible individuals with underlying liver disease, diabetes or other immunocompromised condition and consuming raw seafood, the organism can cause primary septicaemia with a mortality rate of over 50%. A number of putative virulence factors such as capsule, cytotoxic factors, iron acquisition factors and factors responsible for evading the immune system of the host have been described and multiple factors seem to be involved in causing disease symptoms. The organism can be isolated, identified and enumerated by traditional microbiological methods as well as molecular methods such as polymerase chain reaction (PCR) and real time PCR. Clinical strains can be generally distinguished from most environmental strains by genetic fingerprinting techniques. The organism does not grow at temperatures below 13°C and therefore an important control measure is to cool the seafood to temperatures below this within a few hours of harvest. The organism is sensitive to mild heat, which can be used as a postharvest treatment method to minimise the risk of infection. Relaying shellfish to waters with salinity of >30 ppt has also been found to be an important control measure.

Further reading: Foodborne and Waterborne Bacterial Pathogens: Epidemiology, Evolution and Molecular Biology

from Shah M. Faruque and John J. Mekalanos writing in Foodborne and Waterborne Bacterial Pathogens: Epidemiology, Evolution and Molecular Biology:

Vibrio cholerae belonging to O1 and O139 seropgroups cause cholera, a life-threatening diarrhoeal disease, which spreads through consumption of water and food contaminated with the pathogen. Other serogroups of V. cholerae are also occasionally associated with mild to moderate enteric infections. Although V. cholerae is a human pathogen, the bacteria are part of the normal aquatic flora in estuarine and brackish waters, and thus are able to persist in the environment outside the human host. The ability of V. cholerae strains to cause disease in humans depends on their virulence gene content, which varies between pathogenic and nonpathogenic strains. Horizontal transfer of critical virulence genes among different V. cholerae strains, as well as microevolution of bacterial genes contribute significantly to the emergence of V. cholerae strains with altered antigenic and pathobiological properties. Seasonal cholera epidemics may selectively enrich genetic variants with unique properties that promote transmission or environmental persistence. The ecosystem comprising V. cholerae, the aquatic environment and the human host offers an understanding of the complex relationship between pathogenesis and the evolution of a typical waterborne bacterial pathogen.

Further reading: Foodborne and Waterborne Bacterial Pathogens: Epidemiology, Evolution and Molecular Biology

from Indrani Karunasagar, Krishna Kumar and G. Balakrish Nair writing in Foodborne and Waterborne Bacterial Pathogens: Epidemiology, Evolution and Molecular Biology:

Members of the Vibrionaceae family occurring in marine environment are responsible for many of the reported cases of infection worldwide. Among these, Vibrio parahaemolyticus is an important food-borne pathogen transmitted through contaminated seafood. Historically, food poisoning due to V. parahaemolyticus occurred as sporadic cases caused by different serotypes without the clustering of one particular serotype. With the emergence of the pandemic clone belonging to O3:K6 serotype in Kolkata, India, in 1996, the epidemiology of this organism changed abruptly causing large outbreaks and rapid hospitalizations. This new highly virulent strain is now globally disseminated. This review traces the epidemiology of the pandemic strain of V. parahaemolyticus, its emergence, molecular characteristics and clonal dissemination.

Further reading: Foodborne and Waterborne Bacterial Pathogens: Epidemiology, Evolution and Molecular Biology

"brings together 17 expert groups to review aspects of the stress response in bacteria, mycoplasmas, yeast and a range of protozoans. Chapters are of reasonable size, well (and currently) referenced and show a common style, which is a mark of good editing ... well and sensibly illustrated ... will be of interests to bacteriologists, parasitologists and the growing number of scientists interested in the cell stress response." from Brian Henderson (University College London, UK) writing in Microbiology Today (2012) read more ...

Stress Response in Microbiology Edited by: Jose M. Requena ISBN: 978-1-908230-04-1 Publisher: Caister Academic Press Publication Date: June 2012 Cover: hardback "well and sensibly illustrated" (Micro. Today)

from Shah M. Faruque writing in Foodborne and Waterborne Bacterial Pathogens: Epidemiology, Evolution and Molecular Biology:

Recent studies have provided remarkable insights to our general understanding of the epidemiology, genetics, and ecology of foodborne and waterborne bacterial pathogens. Some of these bacteria have recently been reclassified with updated nomenclature; identification methods have also improved substantially with more extensive use of molecular approaches. The bulk of information generated in different areas of research in these pathogenic organisms have been summarized to provide an over all impression of the progress made. Future directions for research into these organisms have also been discussed with a view to understanding general themes of bacterial pathogens, that cause foodborne and waterborne diseases. In addition, available preventive measures to reduce incidences of disease due to these organisms have been discussed.

Further reading: Foodborne and Waterborne Bacterial Pathogens: Epidemiology, Evolution and Molecular Biology

from Lieneke I. Bouwman and Jos P.M. van Putten writing in Foodborne and Waterborne Bacterial Pathogens: Epidemiology, Evolution and Molecular Biology:

Campylobacter species are one of the leading causes of bacterial foodborne disease. Campylobacter survives and flourishes in a variety of environmental niches but causes pathology mainly in humans. The pathogenesis of the disease is still poorly understood, and currently only a few Campylobacter virulence determinants have been proposed. Recent studies indicate that Campylobacter displays extensive genome plasticity and a range of environmental adaptation, that likely contribute to the success of the pathogen. In this review, we will discuss the state-of-the-art of the epidemiology, molecular biology, and pathogenesis of Campylobacter infection.

Further reading: Foodborne and Waterborne Bacterial Pathogens: Epidemiology, Evolution and Molecular Biology

from E. Fidelma Boyd writing in Foodborne and Waterborne Bacterial Pathogens: Epidemiology, Evolution and Molecular Biology:

The acquisition of new phenotypes by bacteria is largely driven by horizontal gene transfer (HGT), a process that is ubiquitous among bacteria and universally present among enteric pathogens. The common vectors of HGT in enteric pathogens include phages, pathogenicity islands and plasmids, all genetic elements that can encode virulence factors essential for host colonization and infection. In this review, Salmonella enterica, Escherichia coli, Vibrio cholerae and V. parahaemolyticus are discussed in terms of their virulence genes encoded within mobile and integrative genetic elements and their role in the mechanism of pathogenesis.

Further reading: Foodborne and Waterborne Bacterial Pathogens: Epidemiology, Evolution and Molecular Biology

from Shah M. Faruque writing in Foodborne and Waterborne Bacterial Pathogens: Epidemiology, Evolution and Molecular Biology:

Foodborne and waterborne bacterial pathogens are a major cause of mortality in developing countries and cause significant morbidity in developed nations. Some countries carry a disproportionately heavy burden of these infectious diseases due to inadequate resources to provide sanitation and hygienic facilities, and safe water. The most important bacterial pathogens transmitted through contaminated water and food include species or strains of Salmonellae, Vibrio (e.g., V. cholerae, V. parahemolyticus, V. vulnificus); Shigella (S. dysnteriae, S. flexneri, S. sonnie, S. boydii); Escherichia coli, Yersinia, Staphylococcus and Campylobacter. The pathogenic mechanisms of these bacteria involve synergistic actions of multiple virulence factors produced by the pathogen after infecting the host. Besides carrying sets of virulence genes which are often horizontally transferred between strains, many of these bacteria may also carry precise genetic programs that allow them to adapt and survive in water leading to enhanced transmission or prolonged persistence in the aquatic environment. Understanding the epidemiology, pathogenesis and evolution of these pathogens can contribute significantly to control foodborne and waterborne diseases.

Further reading: Foodborne and Waterborne Bacterial Pathogens: Epidemiology, Evolution and Molecular Biology

from Julien Brillard and Véronique Broussolle writing in Stress Response in Microbiology:

Among the soil bacteria of the spore former genus Bacillus, the human pathogens mostly belong to the B. cereus group. This species is divided in seven phylogenetic groups, with particular traits in virulence, and particular growth temperature ranges, where each of these seven phylogenetic groups corresponds to a specific "thermotype", showing clear differences in ability to grow at low or high temperatures. After a temperature downshift, changes that occur in the bacterial cell include a decrease of the membrane fluidity, a stabilisation of secondary structures of nucleic acids which consequently causes a decreased efficiency in transcription and translation, a misfolding of some proteins, etc. The bacterial cell response involves various mechanisms which, among the Bacillus genus, have been mostly studied in Bacillus subtilis. This chapter focuses on current research about B. cereus low-temperature adaptation, compared to what is well described in B. subtilis.

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from Indrani Karunasagar, Patit Paban Bhowmick and Deekshit Vijaya Kumar writing in Foodborne and Waterborne Bacterial Pathogens: Epidemiology, Evolution and Molecular Biology:

Foodborne and waterborne infections due to Salmonella species are a major concern worldwide. Several virulence genes have been identified in Salmonella and located in clusters called Salmonella Pathogenicity Island (SPI). There are 17 Pathogenicity Islands of Salmonella reported to date. Salmonella possess two distinct type three secretion system (T3SS) encoded by genes present in two different SPI viz. SPI-1 and SPI-2 that play an important role in adhesion, invasion and survival in the host cells. It has been also reported that a variety of Salmonella phenotypes associated with bioluminescence, biofilm formation, conjugation, motility, competence, and antibiotic production, are regulated in response to signaling molecules of quorum-sensing systems. The development of resistance to various antibiotics (particularly in Asian countries) including extended-spectrum cephalosporins worldwide is a cause of concern. Some variants of Salmonella have developed multidrug-resistance as an integral part of the genetic material of the organism, and are therefore likely to retain their drug-resistance genes even when antimicrobial drugs are no longer used. The role of plasmids, bacteriophages, transposons and integrons in the transfer of resistance genes is discussed.

Further reading: Foodborne and Waterborne Bacterial Pathogens: Epidemiology, Evolution and Molecular Biology

from G. P. Pazhani and T. Ramamurthy writing in Foodborne and Waterborne Bacterial Pathogens: Epidemiology, Evolution and Molecular Biology:

Shigella species are often associated with diarrhoea/dysentery among children in developing countries of Asia-African regions and also cause foodborne infections in developed countries. During infection, this pathogen secretes a number of effectors via the type III secretion system. Recently, Shigella-infected cases have increased considerably in Asia, but the death rate decreased substantially due to nutritional and clinical interventions. Antimicrobials reduce the episodes of shigellosis. However, multiple antibiotic resistance in shigellae have increased over the years due to improper use of antimicrobials in the treatment of diarrhoea. Several mechanisms such as plasmids and other mobile genetic elements are involved in the transmission of resistance in shigellae. Due to poor efficacy of many of the existing Shigella vaccines, none has been licensed for use in endemic areas. This chapter reviews our current understanding of mechanism involved in the pathogenesis of Shigella, antimicrobial resistance and also its epidemiological importance and clinical management of shigellosis.

Further reading: Foodborne and Waterborne Bacterial Pathogens: Epidemiology, Evolution and Molecular Biology

from Isabel Delany and Kate L. Seib writing in Stress Response in Microbiology:

Mechanisms to sense, avoid and scavenge oxidants as well as repair damaged biomolecules are important survival and virulence factors of the obligate human pathogens Neisseria meningitidis and Neisseria gonorrhoeae. These bacteria are routinely exposed to several forms of oxidative and nitrosative stress during colonisation and interaction with the host, of which superoxide, hydrogen peroxide and nitric oxide are some of the key oxidants that result in damage to the bacteria. However, the pathogenic Neisseria express an array of defense mechanisms to combat oxidative and nitrosative stress, such as catalase, superoxide dismutase, nitric oxide reductase, as well as thiol-based defenses and proteins involved in metal homeostasis and repair of damage to DNA and proteins. The expression of these defenses is tightly regulated by a series of transcription factors containing redox-sensitive active sites, including OxyR, Fur, PerR/Zur, FNR, MseR, LexA NsrR, NmlR, which sense and maintain the redox homeostasis of the cell.

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from Kaisar Ali Talukder and Ishrat Jahan Azmi writing in Foodborne and Waterborne Bacterial Pathogens: Epidemiology, Evolution and Molecular Biology:

Shigellosis, also known as acute bacillary dysentery, produces inflammatory reactions and ulceration on the intestinal epithelium followed by bloody or mucoid diarrhoea. Shigellosis is caused by any one of the four species or groups of Shigella, namely, S. dysenteriae, S. flexneri, S. boydii, and S. sonnei. At least 54 serotypes or subtypes of Shigella are currently recognized, of which S. dysenteriae has 16 serotypes, S. flexneri has 17 serotypes and subserotypes, S. boydii has 20 and S. sonnei has a single serotype. Shigellosis can occur in sporadic, epidemic and pandemic forms. To develop an effective vaccine it is important to monitor the prevalent serotypes and their changes around the world because immunity to Shigella is serotype specific. The genetic variability between serotypes and emergence of atypical strains accentuates the problems to the development of an effective vaccine. In view of the emergence of new strains with altered characteristics than the ones established globally for many years, there is also a need for revising the nomenclature for the three groups of Shigella: flexneri, boydii and dysenteriae. This chapter discusses the recent serotyping scheme of Shigella with special focus on the emergence of new variants and the necessity to make an updated scheme. Furthermore, the epidemiology, phenotypic and molecular characteristics, population genetics and clinical impact of these variants have been described.

Further reading: Foodborne and Waterborne Bacterial Pathogens: Epidemiology, Evolution and Molecular Biology

from Mahbubur Rahman writing in Foodborne and Waterborne Bacterial Pathogens: Epidemiology, Evolution and Molecular Biology:

The genus Salmonella has three species namely Salmonella enterica, Salmonella bongori and Salmonella subterranean. The type species S. enterica is further classified into six subspecies: enterica (subsp. I), arizonae (subsp. IIIa), diarizonae (subsp. IIIb), houtenae (subsp. IV), indica (subsp. VI), and salamae (subsp. II). Salmonella strains belong to over 50 serogroups based on the O antigen, and to over 2500 serovars (each having a unique combination of somatic O, flagellar H1 and H2 antigens). Most of these serovars (1,531) belong to Salmonella subsp., enterica, and cause more than 99% of the diseases in humans including gastroenteritis and enteric fever (typhoid). Genome sequencing and comparative genomic analysis of 28 S. enterica serovars identified similarity of core regions of the genomes, together with evidence of recombination and rearrangement, genomic degradation, pseudogenes and clonal diversity both within and among the serovars. Genomic comparisons of host-restricted (S. Typhi, S. Paratyphi and S. Gallinarum) and host-adapted (S. Typhimurium and S. Enteridis) S. enterica serovars indicate that genomic degradation is a common evolutionary mechanism for host adaptation and increased pathogenicity of Salmonella. Drug resistances in Salmonella is mainly due to Salmonella genomic island 1 (an integrative mobile element) carrying various antibiotic resistance gene clusters, and to conjugative R plasmids which confer resistance to many antibiotics including extended-spectrum cephalosporins. Continuous genetic re-assortment in Salmonella leading to increased virulence and the emergence of resistance to multiple drugs are of significant public health concern.

Further reading: Foodborne and Waterborne Bacterial Pathogens: Epidemiology, Evolution and Molecular Biology

from Alfonso Olivos-García, Emma Saavedra, Erika Rubí Luis-García, Mario Nequiz and Ruy Pérez-Tamayo writing in Stress Response in Microbiology:

Several species belonging to the genus Entamoeba can colonize the mouth or the human gut; only Entamoeba histolytica, however, is pathogenic to the host, causing the disease amebiasis. This illness is responsible for one hundred thousand human deaths per year worldwide, affecting mainly underdeveloped countries. Throughout its entire life cycle, or invasion of human tissues, the parasite is constantly subjected to stress conditions. Under in vitro culture, this microaerophilic parasite can tolerate up to 5% oxygen concentrations; however, during tissue invasion the parasite has to cope with the higher oxygen content found in well perfused tissues (4-14%) and with reactive oxygen and nitrogen species (ROS and NOS, respectively) derived from both host and parasite. In almost all living cells, a low-dose, tightly regulated generation of ROS and NOS mediates several physiological functions such as growth, differentiation and metabolism; an excess of ROS and NOS, however, damages DNA, proteins and lipids, leading to cell death. In this chapter we review the latest findings regarding the physiological and pathological molecular functions of oxidative and nitrosative stresses in E. histolytica and discuss whether the molecules involved in the antioxidant system of the parasite can be appropriate drug targets for the treatment of amebiasis.

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from Ewa WaŁecka and Jacek Bania writing in Stress Response in Microbiology:

L. monocytogenes is a food-borne pathogen widespread in the environment. The majority of human listeriosis is associated with consumption of contaminated food. It has the ability to invade many types of nonphagocytic cells and spread from cell to cell, crossing important barriers in host organism. Despite intensified surveillance in food manufacturing serious cases of listeriosis are still reported. Before L. monocytogenes causes disease it has to endure adverse conditions encountered in food during its processing and storage, such as supraoptimal temperatures, low pH, high osmolarity, presence of oxidants. In the human intestinal tract L. monocytogenes must overcome another set of challenges as the low pH of the stomach, volatile fatty acids, low oxygen levels, osmotic stress, nutrient variability, bile stress and natural flora in the intestine. To survive in hostile environment bacteria adjust their metabolism which involves expression of stress response genes. Consequently, bacteria synthesize proteins that repair damages, maintain the cell stability, eliminate the stress factor, and restore homeostasis. The stress response not only affects L. monocytogenes resistance to subsequent doses of stress factors, but can also alter the pathogen's virulence.

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from Melissa L. Madsen and F. Chris Minion writing in Stress Response in Microbiology:

Because mycoplasmas lack cell walls and have a limited genome capacity, there has been interest in their regulation of gene expression in these unique organisms. Their restriction to the host environment only adds to the intrigue. That environment, however, is not constant, changing with the host adaption to colonization and disease by the mycoplasma. This review focuses on the types of stresses the mycoplasma might encounter in vivo including heat shock, oxidative stress, osmolarity shifts, hormone exposure, and iron deprivation. Biofilm studies are included because of their use by other pathogens as a defense measure to resist killing in the host. The field of mycoplasmology is still in its infancy, particularly in regards to gene regulatory mechanisms. There have even been suggestions that mycoplasmas may not have the capacity to respond to changing environmental conditions. The studies reported here, however, show unequivocally that mycoplasmas do respond to their environment by altering transcription rates. How that is accomplished is still unknown except in one instance, heat shock. In summary, like all bacteria, mycoplasmas respond to their environment. That response may be limited, but it appears essential to their survival.

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from Sylke Müller and Christian Doerig writing in Stress Response in Microbiology:

The life cycle of malaria parasites comprises a complex succession of developmental stages occurring in two different hosts, the human patient and the mosquito vector. In both hosts, the parasite encounters hostile environments and must deal with stresses such as immune responses, sharp temperature shifts and exposure to drugs; partly because of large-scale haemoglobin degradation in the infected erythrocyte and resulting haeme release, oxidative stress is another challenge that the parasite must face. In contrast to other eukaryotes where stress response is largely mediated through a well-defined and robust transcriptional response, it appears that malaria parasites opted for a different strategy. In line with the largely fixed transcriptional programme that characterises the progression of the organisms through their life cycle stages, the transcriptional response to several stresses (such as drug treatments) consists primarily of low-amplitude, genome-wide changes of transcript abundance. However, recent findings suggest that specific transcriptome adaptations, that affect selected aspects of the parasites' physiology, also occur. Overall, the absence in the parasite's kinome of classical stress response mediators such as SAPKs/JNKs, together with the relative scarcity in transcription factors, suggest a low level of flexibility of the parasite in implementing classical eukaryotic stress response pathways. Post-transcriptional mechanisms are expected to play crucial roles in stress response in Plasmodium as exemplified by the demonstrated involvement of an eIF2alpha kinases in response to starvation stress.

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from Marcelo A. Comini, Andrea Medeiros and Bruno Manta writing in Stress Response in Microbiology:

African trypanosomes (Trypanosoma brucei sp.) are unicellular eukaryotic organisms that undergo a complex life cycle shuttling between an invertebrate (vector) and a mammalian host. The parasites have evolved sophisticated and efficient mechanisms to cope with, and adapt to, different environmental conditions. Distinct physical (temperature, pH, osmotic pressure) and biological (endo- and exo-biotic molecules, antibodies, proteases, etc) stimuli acting individually or in a concerted manner induce an adaptive response in the parasite. Depending on the nature and extent of the stress, the cellular response can be transient or long-term and associated with minor or major morphological and metabolic changes. In this chapter we compile the most significant molecular and biological aspects related to the mechanisms and components of the stress response of T. brucei to adapt and survive in the bloodstream of mammals.

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from N. Kaye Horstman and Andrew J. Darwin writing in Stress Response in Microbiology:

Pathogenic Yersinia species have long been studied as important causes of human disease and as model organisms to understand widely conserved mechanisms of bacterial virulence. Like all bacteria, these pathogens must respond to a variety of potentially damaging conditions to ensure their survival. This chapter begins by introducing the pathogenic Yersinia and the aspects of their lifestyles that are likely to require successful response to stress. The emphasis is primarily on conditions relevant to pathogenesis. Then, some genome-wide transcription and gene function studies that have identified or implicated stress response mechanisms are summarized. Next, more focused analyses of response to increased and decreased temperature, encounter with macrophages, and macrophage-like conditions are covered in more detail. Finally, the so-called extracytoplasmic stress responses (ESRs) that are activated by changes to the cell envelope will be described. Several of these ESRs have been directly associated with the infectious process in Yersinia. Inactivation of one, the phage-shock-protein (Psp) system, completely attenuates Y. enterocolitica. As a result, the Psp system has become the most extensively studied Yersinia stress response. Therefore, the final section specifically describes the regulation and function of this critical stress response system.

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from Richard W. Stokes writing in Stress Response in Microbiology:

There are many species of mycobacteria, some of which are pathogens of man. Mycobacterium tuberculosis, the etiological agent of tuberculosis, is a major pathogen of man with about one third of the world's population being infected. It resides within host macrophages where it can survive in a dormant state for the lifetime of the host with about 10% of all infections resulting in disease. This environment results in the bacteria being exposed to numerous stresses including nutrient deprivation, reduced oxygen availability, exposure to pH changes and exposure to the antimicrobial activities of the host's cell-mediated immune response. The bacterium responds with its own defense mechanisms that include the increased expression of stress proteins (also called heat shock proteins). This review describes the regulation and function of the major stress proteins within mycobacteria such as the GroEL, GroES and DnaK homologues along with hspX (alpha-crystallin) and others. The multiple copies of cpn60 (GroEL homologue) that are found within mycobacteria are discussed along with their putative roles as chaperonins but also as "moonlighting" proteins with roles in immunomodulation and receptor/ligand interactions that facilitate the pathogenesis of M. tuberculosis.

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from Suzanne Humphrey, Tom J. Humphrey and Mark A. Jepson writing in Stress Response in Microbiology:

Salmonella enterica are the causative agents of a spectrum of diseases, including enteric fever and self-limiting gastroenteritis and remain significant foodborne pathogens throughout both the developed and developing worlds. The ability to actively invade and reside within gut epithelia and macrophages is an important process in the establishment of Salmonella infection, generating localised inflammatory responses and facilitating systemic spread of the pathogen within the host. Many environments, including food matrices, the external environment and conditions within the host, present a range of stressful challenges that Salmonella must overcome in order to survive and establish infection. Salmonella utilise a diverse range of stress response strategies, including expression of alternative RNA polymerase sigma factors, uptake of compatible solutes, increased expression of genes encoding uptake or efflux pumps, and production of proteins with roles in protecting and repairing stress-induced damage, in order to facilitate their survival in suboptimal and stressful growth environments. Additionally, the ability of Salmonella to undergo morphological changes during stress exposure and rapidly recover from stress conditions commonly encountered within food matrices represents a pertinent issue for food processing and public health.

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from Jacqueline Abranches and Josá A. Lemos writing in Stress Response in Microbiology:

The genus Streptococcus is comprised of a diverse group of organisms, which includes food-associated, commensal and pathogenic species. The importance of this genus to the food industry and the capacity of certain species to infect animals and humans make streptococci one of the best-studied Gram-positive bacteria. In this chapter, we will describe the stress responses of the four major pathogenic streptococcal species: Streptococcus mutans, the etiologic agent of dental caries, S. pyogenes (commonly known as Group A Streptococcus or GAS), responsible for a variety of suppurative disesases as well as life-threatening invasive infections and post-infection sequelae, S. agalactiae (Group B Streptococcus or GBS), a major bacterial pathogen associated with neonatal infections, and S. pneumoniae, the leading causative agent of bacterial pneumoniae. In the following pages, the description of the stress response mechanisms for each individual species is presented in the context of the environmental stress condition. In addition to highlighting the cross-species conservation of certain stress reponses, this organization will allow the reader to follow the progresses obtained in each species, and, at the same time, identify areas that have been poorly explored.

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from Eulàlia de Nadal and Francesc Posas writing in Stress Response in Microbiology:

Adaptation to environmental stress requires changes in many aspects of cellular physiology essential for cell survival, such as gene expression, translation, metabolism, morphogenesis or cell cycle progression. Accordingly, the ability of eukaryotic cells to survive and thrive within adverse environments depends on rapid and robust stress responses. Stress-activated protein kinases (SAPKs) pathways are key elements on intracellular stress-signalling networks to respond and adapt to extracellular changes. In this review, we describe the different mechanisms used by model yeasts Saccharomyces cerevisiae and Schizosaccharomyces pombe, as well as the pathogenic fungus Candida albicans, to sense and transduce stress signals to SAPKs in response to osmo, heat and oxidative stresses. Moreover, other signalling pathways related to stress are discussed. Although much remains to be learned, studies from yeast have served to understand how stress signalling molecules adjust precise and efficient adaptation strategies to maximize cell survival in response to extracellular stimuli.

Further reading: Stress Response in Microbiology   Related publications

from Turán P. Ürményi, Deivid C. Rodrigues, Rosane Silva and Edson Rondinelli writing in Stress Response in Microbiology:

Trypanosoma cruzi, the causal agent of Chagas' disease, is a flagellated protozoan parasite with a complex life cycle that involves infecting an insect and a mammalian host. Several environmental stresses occur during its life cycle, such as heat, reactive oxygen species, and osmolarity changes, and the parasite has evolved a variety of stress responses to cope with these challenges. The stress responses range from synthesis of several proteins and small molecules to modulation of the activity of organelles, and they are essential for the parasite's viability and survival in both hosts. Here we review the components and operation of T. cruzi's stress response with emphasis on its relevance to the parasite's biology and to Chagas' disease transmission, pathogenesis and treatment.

Further reading: Stress Response in Microbiology   Related publications

from Jose M. Requena writing in Stress Response in Microbiology:

Leishmania parasites are unicellular protozoa descending from one of the oldest eukaryotic lineages. During its digenetic life cycle, Leishmania alternates between the alimentary tract of the sandfly vector as an extracellular promastigote and the acidic phagolysosomes of macrophage cells as an intracellular amastigote. Parasites must cope with varied and heterogeneous environments: changes in temperature, in pH, in nutrient and oxygen concentrations. Also, they must face the immune defences, such as complement factors, free radicals and other antimicrobial effectors. The focus of this chapter will be on our current knowledge of the different stress responses in Leishmania, ranging from description of the prototypical heat shock response to more specific responses found in this parasite. A comprehensive view on the implications of the stress response in parasite survival, in cytodifferentiation and in apoptotic processes will be presented. Future studies, which should be directed mainly to the uncovering of the stress sensors, signal transduction pathways and regulatory mechanisms leading to the induction of the appropriate stress response will be also discussed.

Further reading: Stress Response in Microbiology   Related publications

from Juan A. Ayala, Felipe Cava and Miguel A. de Pedro writing in Stress Response in Microbiology:

The cell envelope is the major line of defence against environmental threats. It is an essential but vulnerable structure that shapes the cell and counteracts the turgor pressure. It provides a sensory interface, a molecular sieve and a structural support, mediating information flow, transport and assembly of supramolecular structures. Therefore, maintenance of cell envelope integrity in the presence of deleterious conditions is crucial for survival. Several envelope stress responses, including two components regulatory systems (TCRS), of Escherichia coli are involved in the maintenance, adaptation and protection of the bacterial cell wall in response to a variety of stresses. Recent studies indicate that these stress responses exist in many Gram negative pathogens. Particular emphasis has been made on the identified TCRS and their activating signals. Another aspect of stress response is the generation of morphological modifications. Most bacteria alter shape when growth conditions change and upon symbiotic or parasitic processes. Any modification in cell shape is connected with cell wall metabolism and requires specific regulatory mechanisms. Recent advances support the existence of complex mechanisms mediating morphological responses to stress involving inter and intra-specific signalling.

Further reading: Stress Response in Microbiology   Related publications

from W. Brian Whitaker and E. Fidelma Boyd writing in Stress Response in Microbiology:

Members of the genus Vibrio are Gram-negative ubiquitous marine bacteria. They can be isolated directly from the water column but are perhaps most known for their association with eukaryotic organisms. In their association with eukaryotic hosts, be it pathogenic or symbiotic, these bacteria must respond to a variety of stress conditions present within the host environment. Often times, these stress response systems are vitally important for the vibrios to successfully establish in the host. Here, we will discuss the systems used by the three main human pathogens of the genus, V. cholerae, V. parahaemolyticus, and V. vulnificus as well as briefly discussing the stress response systems of V. fischeri, V. splendidus, and V. anguillarum, all of which form close associations with marine organisms.

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from Maria J. Figueras, Sergio O. Angel, Verónica M. Cóceres and Maria L. Alomar writing in Stress Response in Microbiology:

Toxoplasma gondii is an important pathogen of human and domestic animals. It has a complex life cycle which includes the transition from one host to another, being only exposed to the environment during one stage, as highly resistant oocysts. Interestingly, in the intermediate host (non-feline mammalians and birds) the parasite presents an asexual cycle with two stages that can interconvert without its passage in the definite host (felines). The asexual cycle is very important in the establishment of the infection and on its pathogenesis and it could be driven by different kind of stressors. Therefore, the response to environmental and host stresses is essential to their viability and successful progression through their life cycle. The heat shock proteins are key molecules not only in the resistance to different stressors, but they are also involved in the optimal differentiation as well as in other biological processes in T. gondii. This chapter summarizes the findings on different aspects of T. gondii stress responses and the implication of these processes in the biology and pathogenesis of this parasite.

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