Modulation of Pathogenicity

1 - 20 . (canceled)

21 . A compound of Formula XIII, or a pharmaceutically acceptable derivative thereof:

wherein

A 7 is independently C═O, C═S, SO 2 , CH—OR 13 , C═NR 12 , or CH 2 —CHOR 13 ;

A 8 is independently C(R 14 ) 2 , O, S, or NR 12 ;

A 9 is independently C═O, C═S, SO 2 , CH—OR 13 , C═NR 12 , or CH 2 —CHOR 13 ;

m is0, or 1;

q is 0, or 1;

r is 0, or 1;

R 12 is independently H, CH 3 , CH 2 —CH 3 , C 6 H 5 , OCH 3 , OCH 2 —CH 3 , OH, or SH;

R 13 is independently H, CH 3 , or CH 2 —CH 3 ;

R 14 is independently H, alkyl, alkoxy, OH, or SH;

A 5 is a C 3 -C 16 alkyl group optionally substituted by one or more substituents R 3 ; or A 5 is an oxazole group which may be substituted by one or more substituents R 8 , R 8′ or R 9 ,

A 6 is an oxazole group which may be substituted by one or more substituents R 8 , R 8′ or R 9 ,

R 3 is independently OR 4 , SR 4 , hydroxyalkyl, hydroxyalkylamino, cycloalkyl, halogen, haloalkyl, haloalkyloxy, NO 2 , CN, SO 2 NR 4 R 5 , CONR 4 R 5 , COR 4 , CO 2 R 4 , SO 2 R 4 , SO 3 R 4 , NR 4 R 5 , alkyl, or aryl;

R 4 is H, alkyl, cycloalkyl, aryl or heteroaryl;

R 5 is H, alkyl, aryl or heteroaryl, O-alkyl, O-aryl, or O-heteroaryl; and

R 8 , R 8′ , R 9 is independently methyl, ethyl, t-butyl, CN, halogen, haloalkoxy, haloalkyl, OH, alkoxy, NR 4 R 5 , or COOR 4 .

22 . The compound according to claim 21 , wherein A 5 is a C 3 -C 16 alkyl group optionally substituted by one or more substituents R 3 .

23 . The compound according to claim 21 , wherein R 4 is alkyl.

24 . The compound according to claim 21 wherein A 6 is a 1,3-oxazole.

25 . The compound according to claim 22 wherein A 6 is a 1,3-oxazole.

26 . The compound according to claim 21 wherein m is 1.

27 . The compound according to claim 24 wherein m is 1.

28 . The compound according to claim 25 wherein m is 1.

29 . The compound according to claim 27 wherein r is 1.

30 . The compound according to claim 28 wherein r is 1.

31 . The compound according to claim 29 wherein r is 1.

32 . The compound according to claim 30 wherein A 8 is CH 2 .

33 . The compound according to claim 31 wherein A 8 is CH 2 .s

34 . The compound according to claim 32 wherein A 7 is C═O.

35 . The compound according to claim 33 wherein A 7 is C═O.

36 . The compound according to claim 34 wherein A 9 is C═O.

37 . The compound according to claim 35 wherein A 9 is C═O.

38 . The compound according to claim 21 wherein r is 1, m is 1, q is 1, A 7 is C═O, A 9 is C═O, A 8 is CH 2 , R 12 is H, A 5 is an optionally substituted C 5 -C 10 alkyl group and A 6 is an optionally substituted 1,2- or 1,3-oxazole group.

39 . The compound according to claim 38 , wherein the 1,2- or 1,3-oxazole group is substituted with methyl or —C≡N or both.

40 . The compound according to claim 21 , selected from the group consisting of compounds 19, 20, 21, 22, 23, 24, 25, 26, 27, and 28 of Table 2.

41 . A pharmaceutical composition comprising a compound according to claim 21 , and a pharmaceutically acceptable diluent or carrier.

42 . A method for regulating quorum sensing system of a microorganism comprising contacting the microorganism with a composition comprising a compound according to claim 21 .

43 . The method according to claim 42 , wherein the microorganism is a bacterium.

44 . The method according to claim 43 , wherein the microorganism is a gram negative bacterium.

45 . The method according to claim 42 , wherein quorum sensing of the microorganism is inhibited.

46 . A method for treating or preventing bacterial infection in a patient in need thereof, the method comprising administering to the patient an effective amount of a pharmaceutical composition according to claim 41 .

47 . The method according to claim 46 , wherein the bacterial infection is endocarditis, respiratory and pulmonary infections, bacteremia, central nervous system infections, ear infections including external otitis, eye infections, bone and joint infections, urinary tract infections, gastrointestinal infections and skin and soft tissue infections including wound infections, pyoderma and dermatitis which are caused by Pseudomonas aeruginosa ; pulmonary infections caused by Burkholderia cepacia , gastroenteritis and wound infections caused by Aeromonas hydrophila , sepsis in tropical and subtropical areas caused by Chromobacterium violaceum , diarrhoea with blood and haemolytic uremic syndrome (HUS) caused by Escherichia coli , yersiniosis triggered by Yersinia enterocolitica and Y. pseudotuberculosis , and transfusion-related sepsis and fistulous pyoderma caused by Serratia liquefaciens.

48 . The method according to claim 47 , wherein the pulmonary infection is in an immunocompromized or cystic fibrosis patient.

49 . A method for treating biofilm or inhibiting of the formation of biofilm on an object, wherein the biofilm comprises at least a bacterium having a quorum sensing system, the method comprising regulating the quorum sensing system of the bacterium according to claim 42 .

50 . The method according to claim 49 , wherein the object is medical instrument, a medical device, a preparation of disinfectant, a preparation of cleaning solution, a personal hygiene article, a toiletry, a cosmetic preparation, a ship hull, an industrial system, or an environmental system.

51 . The method according to claim 50 , wherein the industrial system or environmental system is selected from the group consisting of a food processing system, a oil recovery system, a paper manufacturing plant, a water treatment plant, a water distribution system, and a refrigeration system.

52 . The method according to claim 42 , wherein a plant disease is treated or damage to the plants caused by an infection by the microorganism is prevented or alleviated.