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From sepsis to necrotizing enterocolitis with appendiceal perforation: a case report of successful salvage therapy with aztreonam–avibactam in an extremely preterm infant with NDM-producing Klebsiella pneumoniae

Year: 2026

Type: article

Abstract: Infections caused by New Delhi metallo-β-lactamase (NDM)-producing Klebsiella pneumoniae represent a major therapeutic challenge in neonatology, particularly in extremely preterm infants, for whom effective options are limited and dosing and safety data for last-resort agents such as aztreonam-avibactam remain scarce. We report the case of a male infants born at 24 +2 weeks of gestation with a birth weight of 530 g who developed Klebsiella pneumoniae sepsis with poor clinical response to aztreonam combined with polymyxin B. His clinical course was complicated by pulmonary hemorrhage, disseminated intravascular coagulation, necrotizing enterocolitis, appendiceal perforation, and suspected necrotizing fasciitis. Blood and ascitic fluid metagenomic next-generation sequencing (mNGS) identified NDM-producing carbapenem-resistant K. pneumoniae . Given the lack of effective alternatives and ongoing clinical deterioration, off-label intravenous aztreonam-avibactam was initiated as salvage therapy. Marked clinical improvement was observed within 4 days after aztreonam-avibactam treatment, blood mNGS converted to negative by day 6, and skin and gastrointestinal manifestations resolved after 10 days of treatment, and no adverse events considered attributable to aztreonam-avibactam were identified. This case suggests that aztreonam-avibactam may be a viable salvage option for life-threatening NDM-producing K. pneumoniae infections in extremely preterm infants, though prospective pharmacokinetic and safety data in this population are urgently warranted.

Source: Frontiers in Pharmacology

DOI: 10.3389/fphar.2026.1919037