A compound of the Formula I: wherein: R 4 is: (a) linear, branched or cyclic alkyl of up to 6 carbon atoms; (b) -(CH 2) x -R 13B, wherein: x is 1-4, and R 13B is -NH 2 or -N + H 3; (c) -(CH 2) x -R 13C, wherein: x is 1-4, and R 13C is -N(R 13D) 2 or-N + (R 13D) 3 wherein R 13D is a linear or branched alkyl of up to 4 carbon atoms; (d) -CH 2 NH-C -O-C(CH 3) 3; or (e) -CH 2 -NH-C -[(CH 2) 2 -O-] y -(CH 2) 2 -R 13E, wherein, y is 1 to 4 and R 13E is -NH 2, -N + H 3, or -N + (CH 3) 3; R 8 is a moiety of the formula: wherein R 8a is -H, or a linear, branched or cyclic alkyl of up to four carbon atoms; A is (a) -CH 2 -; or (b) a moiety of the formula: wherein R 3 is: (i) linear, branched or cyclic alkyl of up to 6 carbon atoms; (ii) -(CH 2) z -R 14A, wherein: z is 1-4, and R 14A is -NH 2 or -N + H 3; (iii) -(CH 2) z -R 14B, wherein: z is 1-4, and R 14B is -N(CH 3) 2 or -N + (CH 3) 3; or (iv) -CH2-NH-C -[(CH 2) y' -O-] 2 -(CH 2) 2 -R 14C, wherein, y' is 1 to 6, and R 14C is -NH 2, -N + H 3, or -N + (CH 3) 3; B is: (a) a moiety of the formula: wherein: R 1 is -H or -NH-C -CH 3; R 2 is -H or -C -R 15A, wherein R 15A is -NH 2, -N + H 3, or - N + (CH 3) 3; and C 1 is -CH 2 - or -(CH 2) 2 -O-; or (b) a moiety of the formula: D is: (a) a moiety of the formula: or (b) a moiety of the formula: wherein R 12 is -H or-CHs; and E is: (a) a moiety of the formula: or (b) a moiety of the formula: or a pharmaceutically acceptable salt thereof; wherein when a compound of Formula I, or a pharmaceutically acceptable salt thereof, is a compound of Formula IV: or a pharmaceutically acceptable salt thereof, and B 2 is: then R 15A may additionally be -N(CH 3) 2. R 4 is: (a) linear, branched or cyclic alkyl of up to 6 carbon atoms; (b) -(CH 2) x -R 13B, wherein: x is 1-4, and R 13B is -NH 2 or -N + H 3; (c) -(CH 2) x -R 13C, wherein: x is 1-4, and R 13C is -N(R 13D) 2 or-N + (R 13D) 3 wherein R 13D is a linear or branched alkyl of up to 4 carbon atoms; (d) -CH 2 NH-C -O-C(CH 3) 3; or (e) -CH 2 -NH-C -[(CH 2) 2 -O-] y -(CH 2) 2 -R 13E, wherein, y is 1 to 4 and R 13E is -NH 2, -N + H 3, or -N + (CH 3) 3; R 8 is a moiety of the formula: wherein R 8a is -H, or a linear, branched or cyclic alkyl of up to four carbon atoms; A is (a) -CH 2 -; or (b) a moiety of the formula: wherein R 3 is: (i) linear, branched or cyclic alkyl of up to 6 carbon atoms; (ii) -(CH 2) z -R 14A, wherein: z is 1-4, and R 14A is -NH 2 or -N + H 3; (iii) -(CH 2) z -R 14B, wherein: z is 1-4, and R 14B is -N(CH 3) 2 or -N + (CH 3) 3; or (iv) -CH2-NH-C -[(CH 2) y' -O-] 2 -(CH 2) 2 -R 14C, wherein, y' is 1 to 6, and R 14C is -NH 2, -N + H 3, or -N + (CH 3) 3; (a) -CH 2 -; or (b) a moiety of the formula: wherein R 3 is: (i) linear, branched or cyclic alkyl of up to 6 carbon atoms; (ii) -(CH 2) z -R 14A, wherein: z is 1-4, and R 14A is -NH 2 or -N + H 3; (iii) -(CH 2) z -R 14B, wherein: z is 1-4, and R 14B is -N(CH 3) 2 or -N + (CH 3) 3; or (iv) -CH2-NH-C -[(CH 2) y' -O-] 2 -(CH 2) 2 -R 14C, wherein, y' is 1 to 6, and R 14C is -NH 2, -N + H 3, or -N + (CH 3) 3; (i) linear, branched or cyclic alkyl of up to 6 carbon atoms; (ii) -(CH 2) z -R 14A, wherein: z is 1-4, and R 14A is -NH 2 or -N + H 3; (iii) -(CH 2) z -R 14B, wherein: z is 1-4, and R 14B is -N(CH 3) 2 or -N + (CH 3) 3; or (iv) -CH2-NH-C -[(CH 2) y' -O-] 2 -(CH 2) 2 -R 14C, wherein, y' is 1 to 6, and R 14C is -NH 2, -N + H 3, or -N + (CH 3) 3; B is: (a) a moiety of the formula: wherein: R 1 is -H or -NH-C -CH 3; R 2 is -H or -C -R 15A, wherein R 15A is -NH 2, -N + H 3, or - N + (CH 3) 3; and C 1 is -CH 2 - or -(CH 2) 2 -O-; or (b) a moiety of the formula: (a) a moiety of the formula: wherein: R 1 is -H or -NH-C -CH 3; R 2 is -H or -C -R 15A, wherein R 15A is -NH 2, -N + H 3, or - N + (CH 3) 3; and C 1 is -CH 2 - or -(CH 2) 2 -O-; or R 1 is -H or -NH-C -CH 3; R 2 is -H or -C -R 15A, wherein R 15A is -NH 2, -N + H 3, or - N + (CH 3) 3; and C 1 is -CH 2 - or -(CH 2) 2 -O-; or (b) a moiety of the formula: D is: (a) a moiety of the formula: or (b) a moiety of the formula: wherein R 12 is -H or-CHs; and (a) a moiety of the formula: or (b) a moiety of the formula: wherein R 12 is -H or-CHs; and E is: (a) a moiety of the formula: or (b) a moiety of the formula: or a pharmaceutically acceptable salt thereof; wherein when a compound of Formula I, or a pharmaceutically acceptable salt thereof, is a compound of Formula IV: or a pharmaceutically acceptable salt thereof, and B 2 is: then R 15A may additionally be -N(CH 3) 2. (a) a moiety of the formula: or (b) a moiety of the formula: or a pharmaceutically acceptable salt thereof; wherein when a compound of Formula I, or a pharmaceutically acceptable salt thereof, is a compound of Formula IV: or a pharmaceutically acceptable salt thereof, and B 2 is: then R 15A may additionally be -N(CH 3) 2. or a pharmaceutically acceptable salt thereof; wherein when a compound of Formula I, or a pharmaceutically acceptable salt thereof, is a compound of Formula IV: or a pharmaceutically acceptable salt thereof, and B 2 is: then R 15A may additionally be -N(CH 3) 2.