The Distribution and Resistance of Pathogens Among Solid Organ Transplant Recipients with Pseudomonas aeruginosa Infections

Recurrent Outbreak of Carbapenem-Resistant IMP-1-Producing Pseudomonas aeruginosa in Kidney Transplant Recipients: The Impact of Prolonged Patient Colonization

BACKGROUND

Infections by carbapenem-resistant Pseudomonas aeruginosa (CRPA) have been associated with high morbidity and mortality among solid organ recipients.

OBJECTIVES

To delineate the epidemiological and molecular characteristics of a recurrent outbreak of imipenem (IMP)-producing P. aeruginosa (CRPA) among kidney transplant (KT) recipient METHODS: We described a recurring CRPA outbreak in a KT ward, divided into two periods: before unit closure (Feb 2019-2020) and after reopening (Aug 2020-Dec 2023). Routine surveillance cultures (SCs) were performed using axillary-perineum-rectal swabs with immunochromatographic tests. A case-control study identified risk factors for CRPA acquisition. Pulsed-field gel electrophoresis and whole genome sequencing characterized the strains.

RESULTS

After reopening, new cases arose from patients previously colonized, peaking 18 months later. A total of 67 KT recipients with CRPA-IMP-producing strains were identified. All except one sequenced strain belonged to the ST446 clone, differing by a maximum of 110 single nucleotide polymorphisms. Forty-five (67.2%) cases were identified through SC, with 45.7% showing intermittent SC positivity. Patients remained colonized for up to 623 days. Twenty-four (35.8%) patients had infections, with the most common site being the urinary tract. Identified risk factors included older age, deceased donor, re-transplantation, reoperation, carbapenem or quinolone use, lymphopenia, hospital stay >10 days, and the first 60 days post-KT.

CONCLUSION

KT recipients can harbor CRPA for extended periods, and detecting CRPA-colonized patients is challenging. These characteristics highlight the patient as the major source and a critical point in outbreak control.

Burden and Management of Multi-Drug Resistant Organism Infections in Solid Organ Transplant Recipients Across the World: A Narrative Review

Solid organ transplant (SOT) recipients are particularly susceptible to infections caused by multidrug-resistant organisms (MDRO) and are often the first to be affected by an emerging resistant pathogen. Unfortunately, their prevalence and impact on morbidity and mortality according to the type of graft is not systematically reported from high-as well as from low and middle-income countries (HIC and LMIC). Thus, epidemiology on MDRO in SOT recipients could be subjected to reporting bias. In addition, screening practices and diagnostic resources may vary between countries, as well as the availability of new drugs. In this review, we aimed to depict the burden of main Gram-negative MDRO in SOT patients across HIC and LMIC and to provide an overview of current diagnostic and therapeutic resources.

Pseudomonas aeruginosa Pneumonia: Evolution of Antimicrobial Resistance and Implications for Therapy

Pseudomonas aeruginosa (PA), a non-lactose-fermenting gram-negative bacillus, is a common cause of nosocomial infections in critically ill or debilitated patients, particularly ventilator-associated pneumonia (VAP), and infections of urinary tract, intra-abdominal, wounds, skin/soft tissue, and bloodstream. PA rarely affects healthy individuals, but may cause serious infections in patients with chronic structural lung disease, comorbidities, advanced age, impaired immune defenses, or with medical devices (e.g., urinary or intravascular catheters, foreign bodies). Treatment of pseudomonal infections is difficult, as PA is intrinsically resistant to multiple antimicrobials, and may acquire new resistance determinants even while on antimicrobial therapy. Mortality associated with pseudomonal VAP or bacteremias is high (> 35%) and optimal therapy is controversial. Over the past three decades, antimicrobial resistance (AMR) among PA has escalated globally, via dissemination of several international multidrug resistant "epidemic" clones. We discuss the importance of PA as a cause of pneumonia including health care-associated pneumonia, hospital-acquired pneumonia, VAP, the emergence of AMR to this pathogen, and approaches to therapy (both empirical and definitive).

Antibiotic-Resistant Infections and Treatment Challenges in the Immunocompromised Host: An Update

This article reviews antibiotic resistance and treatment of bacterial infections in the growing number of patients who are immunocompromised: solid organ transplant recipients, the neutropenic host, and persons with human immunodeficiency virus and AIDS. Specific mechanisms of resistance in both gram-negative and gram-positive bacteria, as well as newer treatment options are addressed elsewhere and are only briefly discussed in the context of the immunocompromised host.