Chapter 44: Antibiotics Part 2 – Aminoglycosides & Fluoroquinolones

A central focus is the urgent threat posed by multidrug-resistant organisms (MDROs), such as methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus (VRE), and strains producing extended-spectrum beta-lactamases (ESBLs) or Klebsiella pneumoniae carbapenemase (KPC). The potent aminoglycosides, including gentamicin and tobramycin, are bactericidal agents primarily used for serious gram-negative infections, often in combination with other antibiotics to achieve a synergistic effect. Due to their associated risks of nephrotoxicity (kidney damage) and ototoxicity (hearing/balance impairment), these drugs require therapeutic drug monitoring, focusing on achieving appropriate trough levels, especially because their effectiveness is based on concentration-dependent killing. Quinolones, or fluoroquinolones (e.g., ciprofloxacin, levofloxacin), are broad-spectrum, bactericidal antibiotics that halt bacterial growth by disrupting DNA synthesis. While highly effective for many systemic and complicated urinary tract infections, they carry serious adverse effects, including a mandated warning for increased risk of tendinitis and tendon rupture, as well as potential for cardiac dysrhythmias linked to QT interval prolongation. Miscellaneous antibiotics covered include clindamycin, which, although useful for anaerobic and chronic bone infections, is strongly linked to pseudomembranous colitis; metronidazole, essential for anaerobic and gynecological infections and requiring patients to avoid alcohol; and vancomycin hydrochloride, the drug of choice for MRSA infections. Vancomycin also demands rigorous therapeutic monitoring and slow infusion rates to prevent vancomycin infusion reaction. Drugs like linezolid and colistimethate sodium are discussed as crucial options for highly resistant pathogens like VRE and KPC-producing bacteria, respectively. Across all these potent classes, nursing care emphasizes comprehensive assessment of renal and neurological function, strict adherence to infusion guidelines, and detailed patient teaching regarding drug interactions, symptom monitoring, and proper hand hygiene to combat the spread of MDROs.