First report of a blaVIM-1 metallo-β-lactamase-possessing Klebsiella michiganensis

OBJECTIVES

Klebsiella michiganensis is an emerging pathogen. Like Klebsiella pneumoniae, this species is able to acquire antibiotic resistance genes (ARGs) via mobile genetic elements. In this context, K. michiganensis isolates producing carbapenemases of KPC, NDM, IMP and OXA-48-like types have already been reported. Here we characterised a strain (BD-50-Km) isolated from a rectal swab of a Turkish patient hospitalised in Switzerland.

METHODS

Species identification was initially performed using MALDI-TOF/MS. Antimicrobial susceptibility testing was done by the microdilution method. Whole-genome sequencing (WGS) was performed with both Illumina and Nanopore platforms and was used to confirm species identification, to characterise plasmids and to perform core-genome analyses.

RESULTS

BD-50-Km was initially identified as Klebsiella oxytoca and showed reduced susceptibility to imipenem. However, WGS indicated that the isolate was actually K. michiganensis. BD-50-Km carried the bla_VIM-1 gene associated with a rare class 1 integron (In87) located on a pST1 196 kb IncC plasmid. This plasmid shares its backbone with many other IncC plasmids found in different species (including five K. michiganensis), but not the same In87 and the remaining region harbouring various ARGs. BD-50-Km belongs to the novel ST342. Moreover, core-genome analysis (single nucleotide variant analysis) showed that BD-50-Km was not closely related to any K. michiganensis strains deposited in NCBI (n = 212), including the 38 so far reported as possessing carbapenemase genes.

CONCLUSION

This is the first report of a bla_VIM-possessing K. michiganensis clinical isolate. The spread of plasmid-mediated VIM carbapenemases in this emerging pathogen represents an additional threat to our therapeutic armamentarium.

Lung resection in hematologic patients with pulmonary invasive fungal disease

BACKGROUND

Pulmonary invasive fungal disease is a frequent complication in patients with hematologic malignancies. Surgical resection in addition to antifungal therapy is an option for selected cases but often feared because of immunosuppression.

METHODS

We analyzed the outcome of 71 patients undergoing lung resection for pulmonary invasive fungal disease. Most patients had leukemia, 44 underwent high-dose chemotherapy, and 18 underwent stem cell transplantation.

RESULTS

On the day of surgery, 44 patients were neutropenic, and 41 had a platelet count < 50 × 109/L. Forty-five nonanatomic (atypical) resections and 26 lobectomies were performed. Fungal infection was histologically proven in 53 patients. Reoperation was needed in four patients (bronchial stump dehiscence, persistent air leak, chylothorax, and seroma). Minor complications at the site of surgery occurred in 14 patients. In only two, there was an uncontrolled disseminated fungal infection. Overall, mortality at 30 days was 7% (five of 71). Long-term survival was mainly influenced by the underlying hematologic disease.

CONCLUSIONS

Lung resection is a therapeutic option for hematologic patients with pulmonary fungal infection. Despite immunosuppression, the perioperative morbidity and mortality is acceptable, and, therefore, the prognosis is not determined by the surgical intervention.