P. aeruginosa is a gram-negative non-sporulating bacillus that belongs to the phylum of Proteobacteria. It can adapt and thrive in different niches, ranging from water/soil to plant/animal tissues. Even though it is commonly found in the environment, it frequently causes infections in plants and animals (1). Luke (1862) was the first to report P. aeruginosa in infections as he observed rod-shaped particles in blue-green pus of some infections. This coloration is a hallmark of P. aeruginosa infections as the microorganism produces the pigment pyocyanin (2).
Most of the clinical cases of P. aeruginosa infections are related with the compromised host defense. It can cause both acute and chronic infections. An acute infection is ventilator-associated pneumonia, which is aggressive and commonly leads to septic shock and death. P. aeruginosa is noted for its …show more content…
aeruginosa has the ability to cope with the host, as it can seek out essential nutrients, avoid eradication by the host immune system and manipulate host cell responses for its own benefit. Most of these strategies are employed by the secretion of virulence factors, which is mediated by secretion systems. Virulence factors can display several activities helpful for bacterial adaptation or pathogenicity, allowing the microorganism to successfully colonize and infect individuals (4).
In gram-negative bacteria, secretion systems are multi-protein complexes that span the cell envelope. Six secretion systems have been described thus far, named as type I secretion system (T1SS) to type VI secretion system (T6SS). P. aeruginosa possesses a broad panel of secretion systems as it encodes five of them (T1SS, T2SS, T3SS, T5SS, T6SS). In some cases, it expresses multiple copies of secretion systems including three evolutionary T6SS clusters; named H1-H3-T6SS gene clusters, making P. aeruginosa an ideal organism to study T6SS (Figure 1) (5).
1.4 The Type VI secretion
Most of the clinical cases of P. aeruginosa infections are related with the compromised host defense. It can cause both acute and chronic infections. An acute infection is ventilator-associated pneumonia, which is aggressive and commonly leads to septic shock and death. P. aeruginosa is noted for its …show more content…
aeruginosa has the ability to cope with the host, as it can seek out essential nutrients, avoid eradication by the host immune system and manipulate host cell responses for its own benefit. Most of these strategies are employed by the secretion of virulence factors, which is mediated by secretion systems. Virulence factors can display several activities helpful for bacterial adaptation or pathogenicity, allowing the microorganism to successfully colonize and infect individuals (4).
In gram-negative bacteria, secretion systems are multi-protein complexes that span the cell envelope. Six secretion systems have been described thus far, named as type I secretion system (T1SS) to type VI secretion system (T6SS). P. aeruginosa possesses a broad panel of secretion systems as it encodes five of them (T1SS, T2SS, T3SS, T5SS, T6SS). In some cases, it expresses multiple copies of secretion systems including three evolutionary T6SS clusters; named H1-H3-T6SS gene clusters, making P. aeruginosa an ideal organism to study T6SS (Figure 1) (5).
1.4 The Type VI secretion