Abstract
Pseudomonas aeruginosa( P. aeruginosa) is an aerobic Gram-negativebacterium that is implicated in the development of severe systemic infections among pediatric patients. It is identified in hospitalized chronically ill pediatric patients in association with genitourinary, respiratory tract, and skin or soft tissue infections as well as severe and life-threating infection including sepsis. A variety of immunologic mechanisms play a vital role in the host defense mechanisms against invasive infections with P. aeruginosa. Rarely, specific inborn errors of immune function are implicated in deficiencies that predispose to invasive infections with P. aeruginosa. Innate immune function including germ-line encoded pattern recognition receptors such as toll-like receptors (TLRs) and their downstream signaling is vital in the host defense against P. aeruginosa through the generation of antimicrobial peptides, cytokines/chemokines, and shaping of adaptive immune responses. Herein, we describe a previously healthy two-year-old female with an invasive skin, soft tissue, and central nervous system infection secondary to P. aeruginosa. The invasive nature of this infection prompted a careful evaluation for an inborn error of immunity. Decreased cytokine response to agonists of TLRs was documented. Targeted sequencing of interleukin-1 receptor-associated kinase (IRAK)-4 documented a homozygous deletion of exons 8-13 consistent with IRAK-4 deficiency. This report provides a vital educative message in the existing scientific literature by underscoring the importance of considering inborn errors of immunity in all patients with severe P. aeruginosa infections. Functional assessments of immune function often in combination with sequencing can accurately assign a diagnosis in a timely fashion allowing for definitive treatment and the use of necessary supportive care.
Highlights
Pseudomonas aeruginosa (P. aeruginosa) is an opportunistic aerobic Gram-negative bacterial pathogen associated with a variety of genitourinary (UTI), pulmonary as well as skin and soft tissue infections (SSTI) in hospitalized pediatric patients often in association with significant morbidity.[1]
Invasive P. aeruginosa infections have been described in the setting of inborn errors of immunity including antibody deficiencies Bruton (BTK), combined immunodeficiency disorders, defects of phagocytes, defects in actin-polymerization (Wiskott-Aldrich syndrome, MKL1-deficiency), chronic neutropenia and innate immunity including defects in canonical NFKB-signaling (e.g., NEMO/NFKBIA) as well as those that impair the downstream signaling of toll-like receptors (TLRs), such as defects in interleukin-1 receptor-associated kinase (IRAK)-4 and myeloid differentiation factor 88 (MyD88).[2,3]
We describe the presence of an invasive soft tissue and central nervous system infection with P. aeruginosa in a previously healthy two-year-old female which prompted evaluation for an inborn error of immunity
Summary
Pseudomonas aeruginosa (P. aeruginosa) is an opportunistic aerobic Gram-negative bacterial pathogen associated with a variety of genitourinary (UTI), pulmonary as well as skin and soft tissue infections (SSTI) in hospitalized pediatric patients often in association with significant morbidity.[1]. Case report A previously healthy two-year-old Hispanic female was evaluated for left hip and knee pain associated with a fever and a refusal to ambulate She had been given cephalexin for presumed insect bites on her back and legs. Her family history was negative for consanguinity and inborn errors of immunity She was afebrile and her physical examination demonstrated a 3 cm circular erythematous lesion on mid left back which was non-indurated. Following the diagnosis of IRAK-4 deficiency she was start prophylaxis with intravenous immunoglobulin (0.5 g/kg/ dose intravenously every 4 weeks) as well as amoxicillin (250 mg orally each day) From her diagnosis at 2 years of age until 4 years of age she continued to experience infrequent infectious complications including a urinary tract infection (Escherichia coli), left knee swelling in association with a abscess (methicillin-susceptible Staphylococcus aureus), and a single admission for fever, cough, and post-tussive emesis. She remains compliant with her prophylaxis therapy with intravenous immunoglobulin therapy and amoxicillin which she has tolerated without complications
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