Chronic infection sustained by a Pseudomonas aeruginosa High-Risk clone producing the VIM-1 metallo-β-lactamase in a cystic fibrosis patient after lung transplantation

Investigating Pseudomonas aeruginosa population structure and frequency of cross-infection in UK cystic fibrosis clinics - a reference laboratory perspective

BACKGROUND

We aimed to describe the UK Pseudomonas aeruginosa population structure amongst people with cystic fibrosis (PWCF), and to examine evidence for cross-infection.

METHODS

Variable Number Tandem Repeat (VNTR) typing was performed on 4640 isolates from 2619 PWCF received from 55 hospital laboratories between 2017 and 2019. A combination of whole genome sequence (WGS)-based analysis of four clusters from one hospital, and epidemiological analysis of shared strains in twelve hospitals evaluated cross-infection.

RESULTS

Of 2619 PWCF, 1324 (51%) harboured common clusters or known transmissible strains, while 1295 carried unique strains/those shared among small numbers of patients. Of the former, 9.5% (250 patients) harboured the Liverpool epidemic strain (LES), followed in prevalence by clone C (7.8%; 205 patients), cluster A (5%;130 patients), and cluster D (3.6%; 94 patients). WGS analysis of 10 LES isolates, 9 of cluster D and 6 isolates each of cluster A and clone C from one hospital revealed LES formed the tightest cluster (between 7 and 205 SNPs), and cluster D the loosest (between 53 and 1531 SNPs). Hospital-specific shared strains were found in some centres, although cross-infection was largely historical, with few new acquisitions. Fifty-nine PWCF (2.3%) harboured "high-risk" clones; one ST235 isolate carried a blaIMP-1 allele.

CONCLUSION

Of 2619 PWCF who had P. aeruginosa isolates submitted for VNTR, 51% harboured either common clusters or known transmissible strains, of which LES was the most common. Limited evidence of recent patient-to-patient strain transmission was found, suggesting cross-infection prevention measures and surveillance effectively reduce transmission.

Management of Multidrug Resistant Infections in Lung Transplant Recipients with Cystic Fibrosis

Cystic fibrosis (CF) is an inherited multisystem disease characterised by bronchiectasis and chronic respiratory infections which eventually cause end stage lung disease. Lung transplantation (LTx) is a well-established treatment option for patients with CF-associated lung disease, improving survival and quality of life. Navigating recurrent infections in the setting of LTx is often difficult, where immune suppression must be balanced against the constant threat of infection. Sepsis/infections are one of the major contributors to post-LTx mortality and multiresistant organisms (eg, Burkholderia cepacia complex, Mycobacterium abscessus complex, Scedosporium spp. and Lomentospora spp.) pose a significant threat to survival. This review will summarize current and novel therapies to assist with the management of multiresistant bacterial, mycobacterial, viral and fungal infections which threaten the CF LTx cohort.

Combination of aztreonam, ceftazidime-avibactam and amikacin in the treatment of VIM-1 Pseudomonas aeruginosa ST235 osteomyelitis

We describe a challenging case of patient with metallo-beta-lactamase-producing Pseudomonas aeruginosa sternal osteomyelitis following aortic valve replacement with biological prosthesis. The strain exhibited a multidrug-resistance phenotype carrying the bla_VIM-1 gene and belonged to the high-risk clone sequence type ST235. The patient was successfully treated with surgical debridement plus antibiotic therapy with ceftazidime/avibactam, aztreonam, and amikacin. Time-kill curves showed that this triple antibiotic combination at 1 × MIC was strongly synergic after 8 h, achieving 99.9% killing and maintaining this until 48 h.

Fatal respiratory infection due to ST308 VIM-1-producing Pseudomonas aeruginosa in a lung transplant recipient: case report and review of the literature

Background

Data regarding the prevalence of metallo-β-lactamases (MBLs) among Pseudomonas aeruginosa isolates in cystic fibrosis patients are scarce. Furthermore, there is limited knowledge on the effect of MBL production on patient outcomes. Here we describe a fatal respiratory infection due to P. aeruginosa producing VIM-type MBLs in a lung transplant recipient and the results of the subsequent epidemiological investigation.

Case presentation

P. aeruginosa isolates collected in the index patient and among patients temporally or spatially linked with the index patient were analyzed in terms of antibiotic susceptibility profile and MBL production. Whole-genome sequencing and phylogenetic reconstruction were also performed for all P. aeruginosa isolates producing VIM-type MBLs. A VIM-producing P. aeruginosa strain was identified in a lung biopsy of a lung transplant recipient with cystic fibrosis. The strain was VIM-1-producer and belonged to the ST308. Despite aggressive treatment, the transplant patient succumbed to the pulmonary infection due to the ST308 strain. A VIM-producing P. aeruginosa strain was also collected from the respiratory samples of a different cystic fibrosis patient attending the same cystic fibrosis center. This isolate harbored the blaVIM-2 gene and belonged to the clone ST175. This patient did not experience an adverse outcome.

Conclusions

This is the first description of a fatal infection due to P. aeruginosa producing VIM-type MBLs in a lung transplant recipient. The circulation of P. aeruginosa isolates harboring MBLs pose a substantial risk to the cystic fibrosis population due to the limited therapeutic options available and their spreading potential.