Screening for other sexually transmitted infections, including syphilis and HIV, is important when you've been diagnosed with a new chlamydia infection.
Having a sexual relationship with one partner (monogamous) who is not infected is one way to avoid chlamydia. The proper use of condoms during intercourse usually prevents infection.
Centers for Disease Control and Prevention (CDC). Update to CDC's sexually transmitted diseases treatment guidelines, 2006: fluoroquinolones no longer recommended for treatment of gonococcal infections. MMWR Morb Mortal Wkly Rep. 2007;56:332-336.
Centers for Disease Control and Prevention. Workowski KA, Berman SM. Diseases characterized by urethritis and cervicitis. Sexually transmitted diseases treatment guidelines 2006. MMWR Morb Mortal Wkly Rep. 2006;55:35-49.