Cross resistance:

• Type of acquired resistance in which resistant bacteria to one drug also become resistant to other drug without having exposed to latter.
• Common among clinically related drugs those share same MOA or attachment.
• It is further divided into two types: Complete and Incomplete

Complete Cross Resistance/ Two-way Cross Resistance:

• In this type of cross-resistance bacteria resistant to one antimicrobial drug are also resistant to second drug and vice-versa.
• Ex; cross-resistance between neomycin & kanamycin and erythromycin & clindamycin.

Partial Cross-Resistance/ One Way Cross Resistance:

• In this type of cross-resistance bacteria resistant to one antimicrobial are also resistant to 2^nd drug but resistant to 2^nd drug doesnot lead to resistance to 1^st antimicrobial drug
• Ex: Resistance to gentamicin leads to resistance to kanamycin but resistance to kanamycin & streptomycin doesnot necessarily be resistant to gentamicin.