Fatal community-acquired bloodstream infection caused by Klebsiella variicola: A case report

BACKGROUND: Klebsiella pneumoniae (K. pneumoniae) is an infective microorganism of worldwide concern because of its varied manifestations and life-threatening potential. Genetic analyses have revealed that subspecies of K. pneumoniae exhibit higher virulence and mortality. However, infections with Klebsiella subspecies are often misdiagnosed and underestimated in the clinic because of difficulties in distinguishing K. pneumoniae from its subspecies using routine tests. This case study reports the rapid and fatal effects of K. pneumoniae subspecies. CASE SUMMARY: A 52-year-old male patient was febrile and admitted to hospital. Examinations excluded viral and fungal causes along with mycoplasma/chlamydia and parasitic infections. Bacterial cultures revealed blood-borne K. pneumoniae sensitive to carbapenem antibiotics, although corresponding treatment failed to improve the patient’s symptoms. His condition worsened and death occurred within 72 h of symptom onset from sepsis shock. Application of the PMseq-DNA Pro high throughput gene detection assay was implemented with results obtained after death showing a mixed infection of K. pneumoniae and Klebsiella variicola (K. variicola). Clinical evidence suggested that K. variicola rather than K. pneumoniae contributed to the patient’s poor prognosis. CONCLUSION: This is the first case report to show patient death from Klebsiella subspecies infection within a short period of time. This case provides a timely reminder of the clinical hazards posed by Klebsiella subspecies and highlights the limitations of classical laboratory methods in guiding anti-infective therapies for complex cases. Moreover, this report serves as reference for physicians diagnosing similar diseases and provides a recommendation to employ early genetic detection to aid patient diagnosis and management.