Phage Lysogeny and Inhibition of Biofilm Formation

描述（由申请人提供）：我们之前报道了铜绿假单胞菌（P. aeruginosa）的转导噬菌体的分离和表征，命名为DMS3，最初从该生物的临床菌株中分离出来。我们实验室最近的研究发现了这种溶原性噬菌体的新作用——在所有体外测试条件下抑制表面附着群落（称为生物膜）形成的能力。DMS3在对实验室菌株P. aeruginosa PA14或几种临床菌株进行溶原作用时，会导致溶原在我们测试的每种条件下都无法形成生物膜，包括在各种碳源（葡萄糖、酪胺酸、LB、精氨酸、有机酸）和各种表面（即PVC和聚苯乙烯塑料、玻璃）上的生长，并且不会影响细菌的生长。这表明噬菌体DMS3的溶原性干扰了铜绿假单胞菌形成生物膜所需的中心途径。虽然我们的大多数研究都涉及噬菌体DMS3，但我们也从铜绿假单胞菌的临床分离株中分离出了几个额外的噬菌体，这些噬菌体也能抑制铜绿假单胞菌的生物膜形成。初步证据表明，其中一种被命名为DMS577的噬菌体与DMS3不同。综上所述，这些数据表明噬菌体DMS3和其他噬菌体可以调节铜绿假单胞菌启动表面附着生活方式的能力。

DESCRIPTION (provided by applicant): We previously reported the isolation and characterization of a transducing phage of P. aeruginosa, designated DMS3, originally isolated from a clinical strain of this organism. Recent studies in our lab have uncovered a new role for this lysogenic bacteriophage - the ability to inhibit the formation of surface- attached communities (known as biofilms) under all in vitro conditions tested. DMS3, when lysogenizing the laboratory strain P. aeruginosa PA14 or several clinical strains, results in a lysogen unable to make a biofilm under every condition we have tested, including growth on a variety of carbon sources (glucose, casamino acids, LB, arginine, organic acids) and on a variety of surfaces (i.e., PVC & polystyrene plastic, glass), and does so without affecting bacterial growth, indicating that lysogeny by phage DMS3 interferes with a central pathway required for biofilm formation by P. aeruginosa. While most of our studies have involved phage DMS3, we also have isolated several additional phages from clinical isolates of P. aeruginosa that also inhibit biofilm formation by P. aeruginosa. Preliminary evidence suggests that one such phage, designated DMS577, is distinct from DMS3. Taken together, these data indicate that phage DMS3 and other phages can modulate the ability of P. aeruginosa to initiate a surface-attached lifestyle. We hypothesize that lysogeny by phage DMS3 or DMS577 blocks biofilm formation by interfering with an essential component of the biofilm formation pathway. The interaction of bacteria and their phages are striking examples of polymicrobial infections resulting in the bacterium acquiring new virulence factors, evolving new pathogenic traits and increasing the ability of the phage-lysogenized microbe to cause disease in a wide range of hosts. Our data suggest that as part of a polymicrobial infection with P. aeruginosa, bacteriophages DMS3 and DMS577 may have the ability to influence the nature and outcome of infections, including chronic suppurative otitis media. To test the hypotheses above, we propose the following Specific Aims for this R21 application: Specific Aim I. Determine the phage DMS3-encoded functions required to inhibit biofilm formation. Specific Aim 2. Determine the step in biofilm formation blocked by phage lysogeny. Specific Aim III. Determine DMA sequence of phage DMS577 and the mechanism by which DMS577 interferes with biofilm formation.