Multidrug-Resistant Gram-Negative Bacteria in Burn Patients
Laura Ruegsegger1, Jamie Xiao1, Arash Naziripour1
1Division of Infectious Diseases, University of North Carolina, Chapel Hill, North Carolina, USA.
Abstract:
Patients with burn injuries are at high risk for infectious complications, and infections are the most common cause of death after the first 72 h of hospitalization. Hospital-acquired infections caused by multidrug resistant (MDR) Gram-negative bacteria (GNB) in this population are concerning. Here, we evaluated carriage with MDR GNB in patients in a large tertiary-care burn intensive care unit. Twenty-nine patients in the burn unit were screened for intestinal carriage. Samples were cultured on selective media. Median time from admission to the burn unit to first sample collection was 9 days (IQR 5 - 17 days). In 21 (72%) patients, MDR GNB were recovered; the most common bacterial species isolated was Pseudomonas aeruginosa, which was found in 11/29 (38%) of patients. Two of these patients later developed bloodstream infections with P. aeruginosa. Transmission of KPC-31-producing ST22 Citrobacter freundii was detected. Samples from two patients grew genetically similar C. freundii isolates that were resistant to ceftazidime-avibactam. On analysis of whole-genome sequencing, blaKPC-31 was part of a Tn4401b transposon that was present on two different plasmids in each C. freundii isolate. Plasmid curing experiments showed that removal of both copies of blaKPC-31 was required to restore susceptibility to ceftazidime-avibactam. In summary, MDR GNB colonization is common in burn patients and patient-to-patient transmission of highly resistant GNB occurs. These results emphasize the ongoing need for infection prevention and antimicrobial stewardship efforts in this highly vulnerable population.
Insights
Multidrug-resistant Gram-negative bacteria (MDR GNB) colonization is common in burn intensive care units. Patient-to-patient transmission of highly resistant GNB, including ceftazidime-avibactam-resistant Citrobacter freundii, was detected, highlighting infection control needs.
Area of Science:
- Infectious Diseases
- Microbiology
- Critical Care Medicine
Background:
- Patients with severe burn injuries face a high risk of infectious complications, a leading cause of mortality after 72 hours of hospitalization.
- Hospital-acquired infections caused by multidrug-resistant Gram-negative bacteria (MDR GNB) are a significant concern in burn intensive care units.
Purpose of the Study:
- To evaluate the prevalence of intestinal carriage of MDR GNB in patients admitted to a tertiary-care burn intensive care unit.
- To investigate the potential for patient-to-patient transmission of specific MDR GNB strains.
Main Methods:
- Screening of 29 burn unit patients for intestinal carriage of MDR GNB using selective culture media.
- Isolation and identification of bacterial species, with a focus on MDR GNB.
- Whole-genome sequencing and plasmid analysis of key isolates, including ceftazidime-avibactam-resistant Citrobacter freundii.
- Plasmid curing experiments to confirm the role of specific genes in resistance.
Main Results:
- MDR GNB were recovered from 21 out of 29 (72%) patients.
- Pseudomonas aeruginosa was the most common species (38%), with two patients developing bloodstream infections.
- Transmission of KPC-31-producing ST22 Citrobacter freundii was identified, including isolates resistant to ceftazidime-avibactam.
- Whole-genome sequencing revealed the blaKPC-31 gene within a Tn4401b transposon on different plasmids in C. freundii.
Conclusions:
- Colonization with MDR GNB is highly prevalent in burn intensive care unit patients.
- Patient-to-patient transmission of highly resistant GNB, such as ceftazidime-avibactam-resistant C. freundii, occurs within this setting.
- Robust infection prevention and antimicrobial stewardship programs are crucial for managing these vulnerable patients.
Related Concept Videos
01:30Development of Antibiotic Resistance
01:28Acute Pyelonephritis II: Diagnostic Studies and Management
01:31Defense Against Bacterial Pathogens
Phagocytes
Phagocytes are the frontline soldiers of the immune system. They include neutrophils and macrophages. Neutrophils are the most abundant type of white blood cell and are quickly mobilized to the site of infection. Macrophages are larger cells that patrol...
01:22Burn Injuries
The damage results in the death of skin cells, which can lead to a massive loss of fluid. Dehydration, electrolyte imbalance, and renal and circulatory failure follow, which can be fatal. Burn patients are treated with intravenous fluids to offset...
01:28Pneumonia IV: Management
Bacterial Pneumonia Treatment
For bacterial pneumonia, antibiotics serve as the cornerstone of therapy. Initial treatment often begins with empirical antibiotics, tailored to the anticipated causative organism and adjusted based on culture results. Key antibiotic choices include:
01:28Pulmonary Tuberculosis V
Latent tuberculosis infection occurs when TB bacteria are present in a person's body, but are not causing illness or symptoms. It is not contagious, and preventive treatment is crucial to avoid the...