What is the treatment for a non-lactose fermenter (NLF) infection?

From the Guidelines

For the treatment of non-lactose fermenter infections, such as those caused by Pseudomonas aeruginosa, the use of antipseudomonal beta-lactams like piperacillin-tazobactam or cefepime, often in combination with an aminoglycoside, is recommended as initial empiric therapy. The choice of antibiotic should be guided by the severity of the infection, the site of infection, and local resistance patterns, as highlighted in the 2017 WSES guidelines for the management of intra-abdominal infections 1.

Key considerations in the treatment of non-lactose fermenter infections include:

• The use of broad-spectrum antibiotics with activity against Pseudomonas aeruginosa, such as piperacillin-tazobactam or cefepime, for initial empiric therapy in healthcare-associated infections or in patients at risk for multidrug-resistant organisms.
• Combination therapy with an aminoglycoside may be considered for synergistic effect, especially in severe infections or in patients with sepsis.
• The importance of adjusting antibiotic therapy based on culture and sensitivity results, as non-lactose fermenters can exhibit intrinsic resistance mechanisms.
• The role of newer antibiotics, such as ceftolozane/tazobactam and ceftazidime/avibactam, which have been approved for the treatment of complicated intra-abdominal infections, including those caused by multidrug-resistant gram-negative bacteria.

In terms of specific treatment regimens, the following options may be considered:

• Piperacillin-tazobactam (4.5g IV every 6-8 hours) or cefepime (2g IV every 8-12 hours) for initial empiric therapy.
• Addition of an aminoglycoside, such as gentamicin (5-7mg/kg IV daily), for synergistic effect in severe infections.
• Use of carbapenems, such as meropenem (1g IV every 8 hours), for multidrug-resistant strains.
• Consideration of newer antibiotics, such as ceftolozane/tazobactam or ceftazidime/avibactam, for the treatment of complicated intra-abdominal infections caused by multidrug-resistant gram-negative bacteria, as recommended by recent guidelines 1.

It is essential to note that the treatment of non-lactose fermenter infections requires a tailored approach, taking into account the specific organism, infection site, and local resistance patterns, as well as the patient's clinical condition and risk factors for multidrug-resistant organisms.

From the FDA Drug Label

Lower Respiratory Tract Infections caused by Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae, Proteus mirabilis, Pseudomonas aeruginosa, Haemophilus influenzae, Haemophilus parainfluenzae, or penicillin-susceptible Streptococcus pneumoniae. Infectious Diarrhea caused by Escherichia coli (enterotoxigenic strains), Campylobacter jejuni, Shigella boydii†, Shigella dysenteriae, Shigella flexneri or Shigella sonnei† when antibacterial therapy is indicated.

Non-lactose fermenter treatment can be achieved with ciprofloxacin (PO) for infections caused by Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae, Proteus mirabilis, or Pseudomonas aeruginosa 2.

• Key points:
  • Ciprofloxacin is effective against various non-lactose fermenters.
  • It is essential to perform culture and susceptibility tests before treatment to ensure the bacteria are susceptible to ciprofloxacin.
  • Therapy with ciprofloxacin may be initiated before test results are known, but appropriate therapy should be continued based on the results.

From the Research

Treatment Options for Non-Lactose Fermenters

• The treatment of non-lactose fermenters, such as certain strains of Escherichia coli, can be challenging due to their resistance to various antibiotics 3.
• According to a study published in 2020, treatment options for urinary tract infections (UTIs) caused by multidrug-resistant (MDR) Pseudomonas spp. include fluoroquinolones, ceftazidime, cefepime, piperacillin-tazobactam, carbapenems, and fosfomycin 4.
• Another study published in 2020 discussed the treatment of less common non-lactose-fermenting Gram-negative bacteria, such as Stenotrophomonas maltophilia and Burkholderia cepacia complex, and highlighted the importance of using novel β-lactam/β-lactamase inhibitors and cefiderocol 5.
• A review of ciprofloxacin published in 1988 noted that it is a broad-spectrum antibacterial drug effective against many Gram-negative bacteria, but its use may be limited by the development of resistance 6.
• Ceftriaxone, a third-generation cephalosporin, has been shown to be effective against a wide range of bacterial infections, including those caused by non-lactose fermenters, but its use may be limited by resistance in certain strains 7.

Antibiotic Resistance and Treatment

• The development of antibiotic resistance is a major concern in the treatment of non-lactose fermenters, and the use of broad-spectrum antibiotics may contribute to the emergence of resistant strains 4, 3.
• The use of novel antibiotics, such as cefiderocol and finafloxacin, may provide alternative treatment options for infections caused by MDR bacteria 4, 5.
• It is essential to use antibiotics wisely and to monitor the development of resistance to ensure the effective treatment of non-lactose fermenters 4, 3.

Specific Treatment Recommendations

• For UTIs caused by ESBL-producing Enterobacteriaceae, treatment options include nitrofurantoin, fosfomycin, pivmecillinam, amoxicillin-clavulanate, and carbapenems 4.
• For UTIs caused by carbapenem-resistant Enterobacteriaceae, treatment options include ceftazidime-avibactam, meropenem/vaborbactam, and colistin 4.
• For infections caused by less common non-lactose-fermenting Gram-negative bacteria, treatment recommendations are based on the specific pathogen and its resistance profile 5.