Clinical Spectrum and Outcomes of Cryptogenic Klebsiella pneumoniae Liver Abscess in the Americas: A Scoping Review

Diversity of hypervirulent Klebsiella pneumoniae clones causing cryptogenic liver abscesses and metastatic complications in Argentina

Cryptogenic liver abscesses (CLA) caused by hypervirulent Klebsiella pneumoniae (hvKP) strains are emerging in Western countries. The aim of the study was to describe the clinical characteristics of patients from Argentina with hvKP-related CLA as well as the molecular analysis of isolated strains. A retrospective chart review of 15 patients hospitalized in 8 hospitals of Argentina between October 2015 and November 2018 was performed. PCR assays for genes associated with capsular and multilocus sequence typing (MLST) determination and virulence factors were conducted in 8 hvKP isolates from these patients. We found that the mean age of patients was 60 years, 73% of them were men and 40% suffered from diabetes. Bacteremia was detected in 60% of them and 73% had ≥1 metastatic foci of infection. There were no in-hospital deaths, but two patients with endophthalmitis required eye enucleation. Of the 8 studied isolates, 4 belonged to K1 and 4 to K2 serotypes, with the rpmA and iroB genes being present in all of them, and isolates 7 and 5 also harboring the iucA and the rmpA2 genes, respectively. MSLT analysis showed that most of the K1 serotypes belonged to ST23 while a diverse MLST pattern was observed among the K2 strains. In addition, the four hvKP strains associated with metastatic complications and belonging to three distinct sequence types, exhibited the rpmA, iroB and iuc virulence genes. We were able to demonstrate important morbidity associated with this syndrome, a significant diversity in the hvKP clones causing CLA in Argentina, and the potential utility of the rpmA and iroB genes as predictors of virulence.

Aggressive Infection by K1/ST1265 Klebsiella pneumoniae Leading to Multiple Abscesses: Case Report and Literature Review

Hypervirulent Klebsiella pneumoniae (hvKp) has attracted increasing attention in recent years. Diabetes and serotype K1 or K2 are risk factors for invasive liver abscess syndrome including liver abscesses and the metastatic complications such as bacteremia, meningitis, endophthalmitis, and necrotizing fasciitis. Simultaneous infections of the liver, lungs, prostate, brain, and eyes are exceedingly rare. In this paper, a 41-year-old male patient who presented with a 4-day history of fever with polydipsia and polyuria and untreated diabetes deteriorated dramatically with sepsis, prostate abscess, lung abscess, liver abscess and intracranial infection as well as endophthalmitis. He was diagnosed with infection by K1/ST1265 hypervirulent Klebsiella pneumoniae and after treatment with antibiotics and abscess drainage, while the patient still passed away. K1/ST1265 hvKp exhibits exceptionally high virulence and invasiveness, necessitating broad awareness and vigilant monitoring.

Prognostic risk factors for pyogenic liver abscess caused by Klebsiella pneumoniae

BACKGROUND

Pyogenic liver abscess (PLA) caused by Klebsiella pneumoniae can vary in severity, and several risk factors for the development of organ dysfunction in PLA have been implicated. However, few studies to date have explored the most common risk factors for clinical severity.

METHODS

We conducted a study on patients with PLA caused by Klebsiella pneumoniae between February 2013 and December 2022.Using logistic regression analysis, we sought to identify factors associated with positive blood culture, septic shock, and intensive care unit (ICU) admission.

RESULTS

After included 200 patients, we found that an elevated procalcitonin (PCT) level (p = 0.03), higher glucose level (p = 0.03), and lower total cholesterol (TC) level (p = 0.01) were associated with a higher likelihood of positive blood bacteriological culture. Additionally, an increased PCT level (p = 0.02) and lower TC level (p < 0.01) were associated with an elevated risk of septic shock. Furthermore, a higher PCT level (p < 0.01) was associated with a higher probability of ICU admission.

CONCLUSION

In patients with PLA caused by Klebsiella pneumoniae, the PCT, glucose, and TC levels were found to be associated with positive blood culture, septic shock, and ICU admission.

Clinical characteristics, effectiveness and cost of different treatment methods for invasive Klebsiella pneumoniae liver abscess syndrome

OBJECTIVES

Bacterial liver abscess is one of the common infectious diseases of the digestive system. Invasive Klebsiella pneumoniae liver abscess syndrome (IKLAS) refers to cases where, in addition to liver abscess, there are migratory infections foci or other invasive manifestations. The clinical characteristics and risk factors of IKLAS are not fully elucidated, and there is a lack of research on the effectiveness and cost-effectiveness of different treatment methods. This study aims to compare the clinical characteristics of patients with IKLAS and non-IKLAS, and explore effective and economical treatment methods.

METHODS

This retrospective study collected medical records of patients with Klebsiella pneumoniae liver abscess treated at Xiangya Hospital of Central South University from January 2010 to December 2023. A total of 201 patients were included, dividing into an IKLAS group (n=37) and a non-IKLAS group (n=164). Differences in demographics, symptoms and signs, laboratory indicators, imaging characteristics, comorbidities, treatment methods, treatment outcomes, and direct treatment costs between 2 groups were analyzed. The study also compared the effectiveness and costs of different treatment methods.

RESULTS

Compared with the non-IKLAS group, the proportion of patients with diabetes, Quick Sequential Organ Failure Assessment (qSOFA)≥2, immune deficiency, anemia, and thrombocytopenia in the IKLAS group was higher, and the level of procalcitonin at the onset in the IKLAS group was also higher (all P<0.05). In terms of symptoms and signs, the IKLAS group had a higher proportion of visual abnormalities and a lower proportion of complaints of abdominal pain (both P<0.05). In terms of complications, the incidence of combined pleural effusion, pulmonary infection, acute renal failure, respiratory failure, and multiple organ failure was higher in the IKLAS group (all P<0.05). The IKLAS group had a higher proportion of patients treated with antibiotics alone (24.32% vs 11.59%), while the non-IKLAS group had a higher proportion of patients treated with antibiotics combined with puncture and drainage (86.59% vs 64.86%, both P<0.05). The overall effective rate of the IKLAS group (83.78%) was lower than that of the non-IKLAS group (95.73%), and the treatment and drug costs were higher (all P<0.05). The treatment method of antibiotics combined with surgical resection of infectious foci showed a 100% improvement rate, antibiotics combined with abscess puncture and drainage had an 84.9% improvement rate, and in antibiotics alone had an 82.1% improvement rate, with statistical differences among the 3 treatment methods (P<0.05). In terms of treatment costs, antibiotics alone were the most expensive (P<0.05).

CONCLUSIONS

Patients with IKLAS have poorer prognosis and higher direct medical costs. The combination of abscess puncture and drainage or surgery has a higher improvement rate and lower hospitalization costs compared to antibiotics alone, suggesting that surgical intervention may reduce antibiotic costs and save medical expenses.

Elevated 68 Ga-FAPI Activity in Klebsiella pneumoniae Invasion Syndrome

ABSTRACT

Klebsiella pneumoniae invasion syndrome is a rare disease associated with primary liver abscess and secondary extrahepatic infection. We report a case of K. pneumoniae invasion syndrome with elevated 68 Ga-FAPI uptake, mimicking malignancy with multiple metastases. Our case illustrated that K. pneumoniae invasion syndrome should be considered as a possible etiology when diagnosing multiple 68 Ga-FAPI-avid liver foci with metastatic lesions. Besides, PET/CT could be an integrated tool to search for systemic occult lesions in K. pneumoniae invasion syndrome.

Pyogenic liver abscess associated with Klebsiella oxytoca: Mimicking invasive liver abscess syndrome

A pyogenic liver abscess (PLA) is a space-occupying lesion in the liver that is associated with significant morbidity and mortality. We herein present the case of a Japanese 76-year-old man who visited our hospital with fever and back pain lasting 3 weeks after endoscopic treatment for common bile duct stones. He was accompanied by poorly controlled diabetes mellitus (DM) with an HbA1c of 9.7 %. Laboratory tests disclosed elevated C-reactive protein level (22.1 mg/dL) and white cell count (11,910/μL). Abdominal computed tomography (CT) revealed hypodense lesions in the right liver lobe, with abdominal ultrasonography showing an echogenicity-mixed hypoechoic lesion. Percutaneous needle aspiration of a liver lesion was performed under suspicion of a PLA. Subsequent enhanced CT and magnetic resonance imaging confirmed the hepatic lesions in the right lobe as well as a septic pulmonary embolism, right hepatic vein thrombosis, spondylodiscitis, and a retroperitoneal abscess. Gram staining of the abscess drainage revealed gram-negative bacteria. The above findings indicated invasive liver abscess syndrome (ILAS) caused by Klebsiella pneumoniae. However, further examination of blood, urine, and abscess drainage cultures revealed positivity for Klebsiella oxytoca. This case illustrates that K. oxytoca may cause ILAS-like symptoms. Screening for systemic metastatic infection should be considered in patients with PLA due to K. oxytoca in whom therapeutic intervention has been delayed, especially in patients with poorly controlled DM.