What antibiotic (abx) is recommended for a patient with a history of Acinetobacter infection and a current urinary tract infection (UTI)?

From the Guidelines

For a urinary tract infection (UTI) with a history of Acinetobacter, carbapenems like meropenem (1g IV every 8 hours) or imipenem-cilastatin (500mg IV every 6 hours) are recommended as first-line therapy, as suggested by the most recent guidelines 1. When considering treatment options, it's essential to note that Acinetobacter baumannii is often multidrug-resistant, making susceptibility testing crucial 1.

• Alternatives to carbapenems include colistin (loading dose of 9 million units followed by 4.5 million units every 12 hours) or polymyxin B if the strain is carbapenem-resistant, as recommended by the 2016 clinical practice guidelines 1.
• Amikacin (15mg/kg IV once daily) may also be effective, but its use should be guided by susceptibility testing and clinical response.
• Treatment duration is typically 7-14 days depending on infection severity, and empiric therapy should be adjusted based on culture results and clinical response, with oral step-down therapy only if susceptibility is confirmed.
• The European Society of Clinical Microbiology and Infectious Diseases (ESCMID) guidelines from 2022 suggest against using cefiderocol for the treatment of infections caused by CRAB, and conditionally recommend against polymyxin-meropenem combination therapy or polymyxin-rifampin combination therapy 1.
• For patients with severe and high-risk CRAB infections, combination therapy including two in vitro active antibiotics among the available antibiotics (polymyxin, aminoglycoside, tigecycline, sulbactam combinations) may be considered, as suggested by the ESCMID guidelines 1.

From the FDA Drug Label

1.2 Urinary Tract Infections (complicated and uncomplicated) Imipenem and Cilastatin for Injection, USP (I.V.) is indicated for the treatment of urinary tract infections (complicated and uncomplicated) caused by susceptible strains of Enterococcus faecalis, Staphylococcus aureus (penicillinase-producing isolates), Enterobacter species, Escherichia coli, Klebsiella species, Morganella morganii, Proteus vulgaris, Providencia rettgeri, Pseudomonas aeruginosa. 1.7 Skin and Skin Structure Infections Imipenem and Cilastatin for Injection, USP (I.V.) is indicated for the treatment of skin and skin structure infections caused by susceptible strains of ... Acinetobacter species, ...

For a patient with a history of Acinetobacter and a UTI, the recommended antibiotic is Imipenem and Cilastatin for Injection, USP (I.V.) 2.

• Key points:
  • The drug label indicates that Imipenem and Cilastatin for Injection, USP (I.V.) is effective against Acinetobacter species.
  • It is also indicated for the treatment of urinary tract infections (complicated and uncomplicated).

From the Research

Treatment Options for UTI caused by Acinetobacter

• The recommended treatment options for UTI caused by Acinetobacter are limited due to its multidrug-resistant nature 3.
• Carbapenems, such as imipenem, meropenem, and doripenem, are considered the mainstay of treatment for Acinetobacter infections, although carbapenem-resistant strains have been increasingly reported 3.
• Other treatment options for Acinetobacter infections include polymyxins E and B, sulbactam, piperacillin/tazobactam, tigecycline, and aminoglycosides 3.
• Colistin has been shown to be effective against Acinetobacter baumannii, with a study demonstrating its efficacy in treating urinary tract infections caused by this pathogen 4, 5.
• Tigecycline-based regimens have also been used to treat complicated urinary tract infections caused by carbapenem-resistant gram-negative bacteria, including Acinetobacter baumannii 6.

Considerations for Treatment

• The choice of treatment should be guided by knowledge of the susceptibility patterns of strains present in the geographical area 3.
• The optimal treatment for Acinetobacter nosocomial infections has not been established, especially for multidrug-resistant strains, and well-designed clinical studies are necessary to guide clinicians on the best therapeutic approach 3.
• It is essential to use antimicrobials wisely to avoid resistance development, especially when treating infections caused by multidrug-resistant organisms 7.