Choosing an empirical antibacterial treatment to treat blood circulation infections caused by Gram-negative pathogens in patients with allergic reactions to β-lactam antibiotics is often a difficult decision for the doctor, as these are the β -lactams which are considered first-line drugs for the treatment of these conditions in most clinical guidelines..

Each year, approximately 500,000 hospital patients in the United States report having allergic reactions to first-line drugs and most commonly report an allergy to penicillin. Besides penicillins, the β-lactams group also includes cephalosporins and carbapenems. If the patient has a history of β-lactam intolerance, they are usually prescribed antimicrobial drugs from other groups, which are second-line drugs for the treatment of the most serious infections. Most often, allergic reactions occur to penicillins or cephalosporins and are manifested by a rash, itching, anaphylaxis, less often other reactions.

The objective of a retrospective study conducted in 3 university medical centers in the United States was to compare the frequency of clinical treatment failure in adult patients with anamnestic data for intolerance to β-lactams having received either antibiotics. β-lactams are antimicrobial agents from other groups. The results of this work were published in the December issue of the Journal of Allergy and Clinical Immunology.

In the study, the treatment groups were classified into β-lactams or non-β-lactams depending on the empirical choice of antibiotics. Clinical ineffectiveness was assessed 72 to 96 hours after the start of antibiotic therapy. A fever of 38.0 ° C and above, the need to use or increase the need to use vasopressors, transfer to the intensive care unit, the need for mechanical ventilation or death have been considered to be signs of clinical treatment failure. Also during the study, hypersensitivity reactions were recorded if they occurred in the patient in the context of the prescribed antibacterial treatment.

In total, the analysis included data from 552 patients: 433 patients in the β-lactam group (78.4%) and 119 patients in the non-β-lactam group (21.6%). It turned out that the frequency of failure of clinical treatment was higher in the group of non-β-lactam antibiotics (38.7% vs 27.4%, p = 0.03). In addition, in the group of non-β-lactams, there was a lower frequency of overlap by the antibiotic empirically prescribed pathogens subsequently selected (74.8% vs 91, 7%, p less than 0.001).

The most common manifestation of clinical ineffectiveness was an increase in temperature above 38.0 ° C 72 to 96 hours after the start of empiric antibiotic therapy (group of non-β-lactams - 22.7% vs 13.9% in the β-lactams group, p = 0.016). After adjusting the data on mechanical ventilation, use of vasopressors and the APACHE II score, it turned out that when non-β-lactams are used, the frequency of ineffectiveness of clinical treatment increases almost twice (the adjusted odds ratio is 1.9, p = 0.012).

Hypersensitivity reactions occurred in 16 of 552 patients (2.9%), of which 13 patients (2.5%) hypersensitivity reactions occurred while using β-lactams to treat infections of blood circulation caused by Gram negative pathogens. However, no case of fatal outcome from the development of an allergic reaction to β-lactams has been recorded.

Thus, in patients with a history of allergic reactions to β-lactams and the presence of blood circulation infections caused by Gram-negative pathogens, the use of this group of antimicrobial agents is associated with a more frequent low clinical treatment failure. The low incidence of hypersensitivity reactions provides further evidence of a fairly low risk of developing cross-allergic reactions between different classes of β-lactams. The results of this study support the current practice of using β-lactams precisely, not alternative antimicrobials from other groups in cases where gram-negative pathogens must overlap.