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Bacterial Adaptation during Chronic Respiratory Infections.

Cullen L, McClean S - Pathogens (2015)

Bottom Line: These adaptations can occur due to environmental pressures in the lung such as inflammatory responses, hypoxia, nutrient deficiency, osmolarity, low pH and antibiotic therapies.Phenotypic adaptations in bacterial pathogens from acute to chronic infection include, but are not limited to, antibiotic resistance, exopolysaccharide production (mucoidy), loss in motility, formation of small colony variants, increased mutation rate, quorum sensing and altered production of virulence factors associated with chronic infection.More recently, the adaptations that other chronically colonising respiratory pathogens, including Staphylococcus aureus, Burkholderia cepacia complex and Haemophilus influenzae undergo during chronic infection have also been investigated.

View Article: PubMed Central - PubMed

Affiliation: Centre of Microbial Host Interactions, Institute of Technology Tallaght, Dublin 24, Ireland. Louise.cullen@postgrad.ittdublin.ie.

ABSTRACT
Chronic lung infections are associated with increased morbidity and mortality for individuals with underlying respiratory conditions such as cystic fibrosis (CF) and chronic obstructive pulmonary disease (COPD). The process of chronic colonisation allows pathogens to adapt over time to cope with changing selection pressures, co-infecting species and antimicrobial therapies. These adaptations can occur due to environmental pressures in the lung such as inflammatory responses, hypoxia, nutrient deficiency, osmolarity, low pH and antibiotic therapies. Phenotypic adaptations in bacterial pathogens from acute to chronic infection include, but are not limited to, antibiotic resistance, exopolysaccharide production (mucoidy), loss in motility, formation of small colony variants, increased mutation rate, quorum sensing and altered production of virulence factors associated with chronic infection. The evolution of Pseudomonas aeruginosa during chronic lung infection has been widely studied. More recently, the adaptations that other chronically colonising respiratory pathogens, including Staphylococcus aureus, Burkholderia cepacia complex and Haemophilus influenzae undergo during chronic infection have also been investigated. This review aims to examine the adaptations utilised by different bacterial pathogens to aid in their evolution from acute to chronic pathogens of the immunocompromised lung including CF and COPD.

No MeSH data available.


Related in: MedlinePlus

Selection and adaptation. Examples of selective pressures to which chronically colonising respiratory pathogens are exposed and the adaptations that they undergo, in order to enhance chances of survival.
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pathogens-04-00066-f001: Selection and adaptation. Examples of selective pressures to which chronically colonising respiratory pathogens are exposed and the adaptations that they undergo, in order to enhance chances of survival.

Mentions: Virulence factors or determinants are often non-essential to the pathogen but, if lost, they inevitably result in attenuated virulence [15]. Bacterial virulence factors are commonly in direct contact with the host or are involved in concealing the pathogen from the host immune system [16]. For example, outer membrane proteins (OMPs) are essential in adhesion, colonisation, intra-cellular invasion, antimicrobial resistance and intracellular communication processes [17]. The proteins can be considerably immunogenic [18]. In addition, the polysaccharide cell wall and capsule have anti-phagocytic properties required for immune evasion. Microbial secretory proteins are involved both in host microbe interactions and in tissue damage. The cell wall and outer membrane moieties such as lipopolysaccharide (LPS) are involved in recognition and host inflammation [16]. It is inevitable that in order for microbial pathogens and populations to chronically colonise a host, they need to adapt to the host environment and evolve over time within the host (Figure 1). The two key drivers for this are the enhanced survival and proliferation of the adapted pathogen to the host environment together with avoiding detection and destruction by the host immune system. Many, but not all, pathogens persist in the lung due to a down regulation of virulence factors and pathogen associated molecular patterns (PAMPS) to avoid detection by the host (Table 1). This review will focus on adaption of pathogens to the host lung during chronic colonisation. The majority of the research has focused on CF-associated pathogens; however, adaptations of bacteria associated with COPD have also been included.


Bacterial Adaptation during Chronic Respiratory Infections.

Cullen L, McClean S - Pathogens (2015)

Selection and adaptation. Examples of selective pressures to which chronically colonising respiratory pathogens are exposed and the adaptations that they undergo, in order to enhance chances of survival.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4384073&req=5

pathogens-04-00066-f001: Selection and adaptation. Examples of selective pressures to which chronically colonising respiratory pathogens are exposed and the adaptations that they undergo, in order to enhance chances of survival.
Mentions: Virulence factors or determinants are often non-essential to the pathogen but, if lost, they inevitably result in attenuated virulence [15]. Bacterial virulence factors are commonly in direct contact with the host or are involved in concealing the pathogen from the host immune system [16]. For example, outer membrane proteins (OMPs) are essential in adhesion, colonisation, intra-cellular invasion, antimicrobial resistance and intracellular communication processes [17]. The proteins can be considerably immunogenic [18]. In addition, the polysaccharide cell wall and capsule have anti-phagocytic properties required for immune evasion. Microbial secretory proteins are involved both in host microbe interactions and in tissue damage. The cell wall and outer membrane moieties such as lipopolysaccharide (LPS) are involved in recognition and host inflammation [16]. It is inevitable that in order for microbial pathogens and populations to chronically colonise a host, they need to adapt to the host environment and evolve over time within the host (Figure 1). The two key drivers for this are the enhanced survival and proliferation of the adapted pathogen to the host environment together with avoiding detection and destruction by the host immune system. Many, but not all, pathogens persist in the lung due to a down regulation of virulence factors and pathogen associated molecular patterns (PAMPS) to avoid detection by the host (Table 1). This review will focus on adaption of pathogens to the host lung during chronic colonisation. The majority of the research has focused on CF-associated pathogens; however, adaptations of bacteria associated with COPD have also been included.

Bottom Line: These adaptations can occur due to environmental pressures in the lung such as inflammatory responses, hypoxia, nutrient deficiency, osmolarity, low pH and antibiotic therapies.Phenotypic adaptations in bacterial pathogens from acute to chronic infection include, but are not limited to, antibiotic resistance, exopolysaccharide production (mucoidy), loss in motility, formation of small colony variants, increased mutation rate, quorum sensing and altered production of virulence factors associated with chronic infection.More recently, the adaptations that other chronically colonising respiratory pathogens, including Staphylococcus aureus, Burkholderia cepacia complex and Haemophilus influenzae undergo during chronic infection have also been investigated.

View Article: PubMed Central - PubMed

Affiliation: Centre of Microbial Host Interactions, Institute of Technology Tallaght, Dublin 24, Ireland. Louise.cullen@postgrad.ittdublin.ie.

ABSTRACT
Chronic lung infections are associated with increased morbidity and mortality for individuals with underlying respiratory conditions such as cystic fibrosis (CF) and chronic obstructive pulmonary disease (COPD). The process of chronic colonisation allows pathogens to adapt over time to cope with changing selection pressures, co-infecting species and antimicrobial therapies. These adaptations can occur due to environmental pressures in the lung such as inflammatory responses, hypoxia, nutrient deficiency, osmolarity, low pH and antibiotic therapies. Phenotypic adaptations in bacterial pathogens from acute to chronic infection include, but are not limited to, antibiotic resistance, exopolysaccharide production (mucoidy), loss in motility, formation of small colony variants, increased mutation rate, quorum sensing and altered production of virulence factors associated with chronic infection. The evolution of Pseudomonas aeruginosa during chronic lung infection has been widely studied. More recently, the adaptations that other chronically colonising respiratory pathogens, including Staphylococcus aureus, Burkholderia cepacia complex and Haemophilus influenzae undergo during chronic infection have also been investigated. This review aims to examine the adaptations utilised by different bacterial pathogens to aid in their evolution from acute to chronic pathogens of the immunocompromised lung including CF and COPD.

No MeSH data available.


Related in: MedlinePlus