Comparison of pyogenic liver abscesses caused by hypermucoviscous Klebsiella pneumoniae and non-Klebsiella pneumoniae pathogens in Beijing: a retrospective analysis

Demographics and prognosis of patients with pyogenic liver abscess due to Klebsiella pneumonia or other species

Background

Pyogenic liver abscess (PLA) is a potentially life-threatening intra-abdominal infection. We compared the clinical features, treatments, and prognoses of patients who had Klebsiella pneumonia pyogenic liver abscess (KPPLA) and non-Klebsiella pneumonia pyogenic liver abscess (non-KPPLA).

Methods

A retrospective analysis was used to compare the medical records of KPPLA and non-KPPLA patients with positive pus cultures at a single hospital in China from January 2017 to December 2019.

Results

We examined 279 patients with definitively established PLA, 207 (74.2 %) with KPPLA, and 72 with non-KPPLA. The non-KPPLA group had a higher Charlson comorbidity index, longer hospital stay, longer duration of fever, and greater hospital costs. Multivariate analysis showed that alcohol intake (OR: 2.44, P = 0.048), cancer (OR: 4.80, P = 0.001), ICU admission (OR: 10.61, P = 0.026), resolution of fever OR: 1.04, P = 0.020), and a positive blood culture (OR: 2.87, P = 0.029) were independent predictors of primary treatment failure. Percutaneous needle aspiration (PNA) and pigtail catheter drainage (PCD) provided satisfactory outcomes, but PNA led to shorter hospital stays and reduced costs, especially in KPPLA patients whose abscesses were smaller than 10 cm.

Conclusion

KPPLA and non-KPPLA patients had some differences in comorbidities and treatment strategies, and non-KPPLA patients had a significantly worse prognosis.

Successful treatment of invasive liver abscess syndrome caused by Klebsiella variicola with intracranial infection and septic shock: A case report

BACKGROUND

Klebsiella variicola (K. variicola) is a member of the Klebsiella genus and is often misidentified as Klebsiella pneumoniae. In this report, we present a rare case of invasive liver abscess caused by K. variicola.

CASE SUMMARY

We report a rare case of liver abscess due to K. variicola. A 57-year-old female patient presented with back pain for a month. She developed a high-grade fever associated with chills, and went into a coma and developed shock. The clinical examinations and tests after admission confirmed a diagnosis of primary liver abscess caused by K. variicola complicated by intracranial infection and septic shock. The patient successfully recovered following early percutaneous drainage of the abscess, prompt appropriate antibiotic administration, and timely open surgical drainage.

CONCLUSION

This is a case of successful treatment of invasive liver abscess syndrome caused by K. variicola, which has rarely been reported. The findings of this report point to the need for further study of this disease.

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

(1) Background: Cryptogenic Klebsiella pneumoniae liver abscesses are an invasive infection with or without extra hepatic involvement in the absence of hepatobiliary disease or abdominal malignancy. Most of the evidence has emanated from reports from Asia, and previous studies in the Americas have limited clinical characterization. (2) Methods: To understand this syndrome's characteristics on our continent, we conducted a scoping review to identify adult cases of idiopathic, community-acquired monomicrobial K. pneumoniae liver abscess in the Americas. (3) Results: We identified 144 cases spanning 1978-2022. Most cases were reported in males that had traveled or migrated from Southeast or East Asia with diabetes mellitus. Extrahepatic involvement and bacteremia were common, including seeding to the lungs, ocular structures, and central nervous system. Although limited by sample size, the most commonly reported genes were magA or rmpA. Concomitant percutaneous drainage and third generation cephalosporins (alone or in combination with other antibiotics) were frequently used, yet pooled fatality occurred in 9% of the reported cases. (4) Conclusions: The features of cryptogenic K. pneumoniae liver abscess in the Americas mirror those described in Asia, confirming its global dissemination. This condition is increasingly being reported in our continent and carries significant clinical impact due to its systemic invasiveness.

Clinical characteristics and management of 106 patients with pyogenic liver abscess in a traditional Chinese hospital

This is a retrospective study of clinical data from 106 patients with pyogenic liver abscess (PLA) treated in a traditional Chinese hospital during the eight years preceding this publication. We aimed to provide evidence to improve the diagnosis accuracy and the treatment strategies for PLAs. We collected records of patients treated at the Guangxing Hospital, which is affiliated to the Zhejiang Traditional Chinese University in Hangzhou, and we collected their general background information, laboratory and imaging features, and clinical manifestations and outcomes to perform a retrospective analysis. Diabetes mellitus (45.3%, 48/106), biliary calculi (36.8%, 39/106), and history of abdominal surgery (15.1%, 16/106) were the three most common PLA risk factors present in our cohort. Fever and chills (95.3%, 101/106), right upper quadrant pain/epigastric discomfort (68.9%, 73/106), nausea and vomiting (38.8%, 41/106), and cough and sputum (14.2%, 15/106) were the most common clinical manifestations of PLA. Most patients had the abscesses in the right liver lobe, and the most commonly found bacteria were Klebsiella pneumoniae (54.8%, 42/76), Escherichia coli (35.1%, 27/76), and Streptococcus pneumoniae (3.9%, 3/76). Liver Doppler ultrasound is a conventional and effective method to identify liver abscesses. Most patients were treated using a percutaneous puncture under B-ultrasound guidance. Most patients (n = 104 or 98.1%) were cured, one patient (0.9%) died, and one was discharged with multiple abscesses post treatment.

A complex presentation of an uncommon disease: Gas-forming pyogenic liver abscess complicated by septic pulmonary emboli and muscle abscesses, a case report and review of the literature

Background

Pyogenic liver abscess (PLA) is the most common type of visceral abscess. Its variable clinical presentation depends on patient demography, underlying conditions, causative pathogens as well as the size of the abscess. Most cases are secondary to enteric pathogens that cause focal liver disease. Gas-forming pyogenic liver abscess (GFPLA) is a rare subgroup of PLA characterized by the presence of gas within the abscess. The disease is associated with diabetes mellitus (DM) while Klebsiella penumoniae is the most frequently isolated pathogen. Despite appropriate evaluation and management, secondary complications are common with significant morbidity and mortality that necessitate prompt recognition and management.

Case presentation

We present a case of a 46-year-old gentleman from Bangladesh who presented to the emergency department with fever, chills, and right upper quadrant abdominal discomfort. Evaluation revealed elevated inflammatory markers with high blood glucose and a subdiaphragmatic lucency on a plain chest radiograph. The suspected underlying visceral infection was confirmed by abdominal ultrasonography and computed tomography which demonstrated an emphysematous abscess of 8 cm in diameter in the right liver lobe.Because of clinical instability, the patient was admitted to the medical intensive care unit (MICU) where he received appropriate supportive management with antimicrobials and percutaneous drainage of the abscess. Cultures collected from blood, the abscess, and urine grew a sensitive strain of Klebsiella pneumoniae. During his stay in the MICU, he complained of dyspnea. A CT pulmonary angiography was suggestive of septic emboli. A few days later, the patient started to complain of left gluteal pain and an US revealed a deep left gluteal abscess which required drainage. Cultures of the pus grew the same sensitive strain of Klebsiella pneumoniae. After receiving 6 weeks of parenteral antimicrobial therapy a repeated US revealed complete resolution of the abscess in the liver. Outpatient follow up showed favorable recovery.

Conclusion

Gas-forming pyogenic liver abscess (GFPLA) is a rare manifestation of pyogenic liver abscess that usually occurs in patients with poorly controlled DM. Despite appropriate evaluation, morbidity remains high therefore timely recognition and anticipation of complications is important.

Siderophore iucA of hypermucoviscous Klebsiella pneumoniae promotes liver damage in mice by inducing oxidative stress

The hypermucoviscosity/hypervirulent K. pneumoniae (hvKP) is a dominant cause of pyogenic liver abscess (PLA) and has contributed to the endemicity of disease in Asian country. The siderophore aerobactin (iucA) is highly expressed in hvKP and acting virulence role during hvKP infection. However, its role in the PLA is poorly understood. We constructed iucA deletion mutant (ΔiucA-hvKP852) and used animal study to characterize the role of siderophore iucA in K. pneumoniae liver abscess. The animal experiments showed that ΔiucA-hvKP852 strain had lower virulence in mice compared to hvKP852 wild type strain. At 24 h after infection, only two of ten mice developed liver abscess during infection with ΔiucA-hvKP852 strain, while nine of ten mice infected with wild type hvKP852 strain showed multiple lesions of liver abscess. The liver tissue infected with ΔiucA-hvKP852 exhibited low reactive oxygen stress levels compared to those infected by wild type hvKP852 strain (P < 0.05). The results suggest that siderophore iucA play an important role in the liver abscess by inducing oxidative stress.

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iucA positive strains produces more siderophore than iucA negative hvK. pneumoniae.

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Siderophore production is positively related with Oxidative stress in hvK. pneumoniae.

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iucA enhances oxidative stress in liver and forms liver abscess during hvK. pneumoniae infection.

Demographics, Radiological Findings, and Clinical Outcomes of Klebsiella pneumonia vs. Non-Klebsiella pneumoniae Pyogenic Liver Abscess: A Systematic Review and Meta-Analysis with Trial Sequential Analysis

Pyogenic liver abscess (PLA) is a common cause of hepatobiliary sepsis. Klebsiella pneumoniae (KP) is the most common organism causing PLA. Evidence is scarce on the demographics, radiological findings, and outcomes of KPPLA versus non-KPPLA (N-KPPLA). PubMed, Embase, The Cochrane Library, and Scopus were systematically searched until 14 May 2022 for studies comparing KPPLA and N-KPPLA. Exclusion criteria were single-arm studies. Primary outcomes were mortality (30-day/in-hospital) and metastatic complications. There were 16 studies, including 5127 patients (KPPLA n = 3305, N-KPPLA n = 1822). Patients with KPPLA were younger (mean difference: −2.04 years, p = 0.02). History of hepatobiliary disease (Odds ratio (OR) 0.30, 95% CI: 0.20, 0.46) and malignancy (OR 0.26, 95% CI: 0.16, 0.42) were less common in KPPLA. KPPLA was associated with lower incidence of multiple abscesses (OR 0.52, 95% CI: 0.35, 0.76, p < 0.001) and bilobar abscesses (OR 0.60, 95% CI: 0.49, 0.74, p < 0.001). KPPLA has higher overall metastatic complications (KPPLA 9.7% vs. N-KPPLA 4.8%, OR 3.16, 95% CI: 2.00, 4.99, p < 0.001), but lower mortality (KPPLA 3.9% vs. N-KPPLA 7.6%, OR 0.51, 95% CI: 0.34, 0.78, p < 0.001). Trial sequential analysis showed conclusive evidence that KPPLA has lower mortality than N-KPPLA. In conclusion, KPPLA has lower mortality than N-KPPLA.

Emergence of K1 ST23 and K2 ST65 hypervirulent klebsiella pneumoniae as true pathogens with specific virulence genes in cryptogenic pyogenic liver abscesses Shiraz Iran

Hypervirulent Klebsiella pneumoniae (hvKp) pathotype is emerging worldwide in pyogenic liver abscesses (PLAs). However, the role of virulence factors in pathogenicity remains unclear. On the other hand, the epidemiology of PLAs in Iran is unknown. From July 2020 to April 2022, bacterial species were isolated and identified from the drainage samples of 54 patients with PLAs. K. pneumoniae as the most common pathogen of pyogenic liver abscesses was identified in 20 (37%) of the 54 patients. We analyzed the clinical and microbiological characteristics of K. pneumoniae-related pyogenic liver abscesses. Antibiotic susceptibility testes and string test were performed. 16S rRNA, antibiotic resistance, and virulence genes were determined by polymerase chain reaction amplification. Clonal relatedness of isolates was identified by multilocus sequence typing. Virulence levels were assessed in the Galleria mellonella larval infection model. Four hvKp isolates (K1/K2) were found to be responsible for cryptogenic PLAs, and 16 classical K. pneumoniae isolates (non-K1/K2) were associated with non-cryptogenic PLAs. Three capsular serotype K1 strains belonged to sequence type 23 (ST23) and one K2 strain to ST65. Meanwhile, the non-K1/K2 strains belonged to other STs. ST231 was the most common strain among the classical K. pneumoniae strains. Compared with the non-K1/K2 strains, capsular serotypes K1/K2 strains were less resistant to antibiotics, had positive string test results, and had more virulence genes. In Galleria mellonella, a concentration of 10⁶ colony-forming units of the K1 hvKp strain resulted in 100% death at 24 hours, confirming the higher virulence of the hvKp strain compared with cKp. K. pneumoniae isolates represented that the acquisition of any plasmid or chromosomal virulence genes contributes to pathogenicity and high prevalence in PLAs. Meanwhile, hvKp isolates with a specific genetic background were detected in cryptogenic PLAs.

Klebsiella pneumoniae liver abscess with endophthalmitis in a diabetic man with gallstones

Invasive liver abscess syndrome (ILAS) is caused by Klebsiella pneumoniae and is typically seen in people from East Asia, often with diabetes and gallstones. ILAS includes metastatic sequelae of the infection, commonly to the eyes. The case described below occurred in a London hospital. The patient's abscess was diagnosed on CT and MRI and he developed endophthalmitis secondary to metastatic spread of the infection. He was treated with intravenous and intravitreal antibiotics and discharged with a plan for vitrectomy and cholecystectomy as an outpatient. We discuss the epidemiology, risk factors, pathogenesis, prognosis and management of this rare condition. There have been a number of recent reports of cases of this nature outside of Asia and we believe greater awareness is required. A high index of suspicion should be held for the potential development of metastases in patients of this demographic presenting with abscesses of this nature.

Incidence, Risk Factors and Clinical Outcomes of Patients with Hypermucoviscoid Klebsiella in a Tertiary Intensive Care Unit

Background and Objectives:

Hypermucoviscoid Klebsiella(hvKP), a dreaded variant of Klebsiella, so far, fewer cases were reported from the community. This study was designed to evaluate the incidence of hvKP isolates, risk factors for hvKP infections, antibiotic sensitivity pattern and clinical outcome including morbidity and mortality.

Patients and Setting:

Patients who have got admitted under medical intensive care unit (MICU) and had positive culture of Klebsiella infections.

Materials and Methods:

This study was conducted at department of MICU at a tertiary care hospital between January 2018 and December 2018. A standardized proforma was prepared and data was collected, which includes basic demographics of the patients, co-morbidities, clinical details and mortality. This study was approved by the Institutional Review Board and Ethics Committee.

Results:

A total of 165 patients (males, 123; 74.5%) had Klebsiella pneumoniae infection during the study period, out of whom 32 was hvKP (19.4%). The mean age was 53.1 ± 16.8 years. Among the 32 hvKP patients, 22 (68.8%) were hospital acquired infection (HAI) and 10 were (31.2%) community acquired infection. The overall mortality rate of hvKP infection was 56.2% (18/32). The incidence of mortality rate was similar in patients having pan-drug sensitive and in patients with extreme drug-resistance (61.9% vs. 66.7%; P = 0.831). HAI is significantly associated with multi drug resistance of hvKP (odds ratio [OR], 7.917; P < 0.05) and diabetes is associated with increased risk of hvKP related mortality (OR, 5.250; P = 0.054).

Conclusions:

Our study results showed, increased incidence of HAI with hvKP predominantly associated with pneumonia and increase in trend of drug resistance with two cases being pan resistant. More number of studies are required to evaluate the existing antibiotics strategy and steps to curb the spread of this dreaded infection.

A retrospective study of pyogenic liver abscess caused primarily by Klebsiella pneumoniae vs. non-Klebsiella pneumoniae: CT and clinical differentiation

PURPOSE

The incidence of Klebsiella pneumoniae pyogenic liver abscesses (KP-PLA) is increasing. However, its diagnosis and treatment are often delayed, leading to complications. In this study, we aimed to retrospectively compare computed tomographic (CT) features of KP-PLAs with those of abscesses caused by other bacterial pathogens (non-KP-PLAS) and to further identify prognostic factors for PLA.

METHODS

Data of 219 study patients including clinical presentation, comorbid conditions, metastatic infection, treatment duration, and mortality were retrospectively collated. CT characteristics of abscesses were recorded. Etiology was established by pus and/or blood culture. The differentiating CT features and clinical findings were compared between the monomicrobial KP-PLA and non-KP-PLA groups. Furthermore, factors related to in-hospital case fatality were analyzed.

RESULTS

Multivariate analysis identified thin-walled abscesses, absent rim enhancement, metastatic infection, and absence of underlying biliary tract disease as significant predictors of KP-PLA. With 3/4 criteria applied in combination, a specificity of 96.5% was achieved for KP-PLA diagnosis. The in-hospital mortality rate was 3.7%. Multivariate analysis revealed that diabetes mellitus (P = 0.031), multiple abscesses (P = 0.026), internal gas bubble (P = 0.041), metastatic infection (P = 0.004), and septic shock (P = 0.002) were significantly associated with mortality.

CONCLUSION

Thin-walled abscess, metastatic infection, absence of rim enhancement, and absence of underlying biliary tract disease are potentially useful CT findings for early KP-PLA diagnosis.

Hypervirulent Klebsiella pneumoniae - clinical and molecular perspectives

Hypervirulent Klebsiella pneumoniae (hvKp) has emerged as a concerning global pathogen. hvKp is more virulent than classical K. pneumoniae (cKp) and capable of causing community-acquired infections, often in healthy individuals. hvKp is carried in the gastrointestinal tract, which contributes to its spread in the community and healthcare settings. First recognized in Asia, hvKp arose as a leading cause of pyogenic liver abscesses. In the decades since, hvKp has spread globally and causes a variety of infections. In addition to liver abscesses, hvKp is distinct from cKp in its ability to metastasize to distant sites, including most commonly the eye, lung and central nervous system (CNS). hvKp has also been implicated in primary extrahepatic infections including bacteremia, pneumonia and soft tissue infections. The genetic determinants of hypervirulence are often found on large virulence plasmids as well as chromosomal mobile genetic elements which can be used as biomarkers to distinguish hvKp from cKp clinical isolates. These distinct virulence determinants of hvKp include up to four siderophore systems for iron acquisition, increased capsule production, K1 and K2 capsule types, and the colibactin toxin. Additionally, hvKp strains demonstrate hypermucoviscosity, a phenotypic description of hvKp in laboratory conditions that has become a distinguishing feature of many hypervirulent isolates. Alarmingly, multidrug-resistant hypervirulent strains have emerged, creating a new challenge in combating this already dangerous pathogen.

Diagnosis efficacy of CEUS for hepatic inflammatory lesions

Purpose

In this study, the efficacy of US/CEUS and clinicopathologic parameters in differential diagnosis of hepatic inflammatory lesions were evaluated.

Methods

This was a retrospective study in which CEUS imaging was performed on 182 patients. Among these patients, 44 patients had hepatic inflammatory lesions and 138 patients had malignant lesions. The ultrasound (US), CEUS, and clinicopathologic parameters with respect to differential diagnosis of hepatic inflammatory lesions were analyzed.

Results

Irregular lesion shape and unclear margin were commonly seen in hepatic inflammatory lesions by US/CEUS examination. Hypoenhancement in arterial phase (AP) and portal venous phase (PVP), and isoenhancement in delayed phase (DP) were more commonly found in inflammatory lesions rather than malignant lesions [9% (4/44), 68% (30/44), and 16% (7/44) vs 2% (3/138), 11% (15/138), 1% (1/138), respectively; P < .05]. The enhancement coverage was also a significant indicator for the differentiation of inflammatory lesions and malignant lesions (P < .05). History of hepatitis or cirrhosis, and higher serum alpha‐fetoprotein (AFP) level were indicators for malignant lesions, while liver parasites and higher body temperature were indicators for inflammatory lesions. When the US/CEUS findings were combined with clinicopathologic parameters, the diagnostic accuracy of inflammatory lesions could reach 93.3%, with sensitivity, specificity, positive predictive value, and negative predictive value of 63.64%, 96.03%, 84.85%, and 88.32%, respectively.

Conclusion

The US/CEUS findings combined with clinical characteristics can accurately differentiate hepatic inflammatory lesions and malignant lesions. The results of study will improve the diagnostic confidence for hepatic inflammatory lesions.

Prognostic nomogram for the combination therapy of percutaneous catheter drainage and antibiotics in pyogenic liver abscess patients

PURPOSE

To identify the predictors for recovery of pyogenic liver abscess (PLA) patients treated with percutaneous catheter drainage (PCD) and antibiotics, and then develop an effective nomogram to predict the recovery time.

MATERIALS AND METHODS

The retrospective study included consecutive PLA patients treated with PCD and antibiotics. We defined the overall recovery time (ORT) as the time from the PCD procedure to the time of clinical success or failure. Based on the ORT, its predictors were identified with univariate and multivariate analyses. Then, a nomogram was developed to predict the ORT, and was internally validated by using Harrell's c statistic.

RESULTS

A total of 116 patients and 142 PCD procedures with a median ORT of 15.0±10.6 days were included. Gas-formation (GF; HR: 0.486 [95% CI 0.312-0.757]; P = 0.001), diabetes mellitus (DM; HR: 0.455 [95% CI 0.303-0.682]; P<0.001), and preinterventional septic shock (PSS; HR: 0.276 [95% CI 0.158-0.483]; P < 0.001) were identified as predictors for the ORT of combination therapy after univariate and multivariate analyses, which indicated a significantly longer ORT than those patients without. The prognostic analyses demonstrated that the more predictors (GF, DM, and PSS) a patient exhibited, the longer ORT for the combination therapy. A nomogram was developed to predict the ORT and revealed high accuracy, with Harrell's c statistic of 0.73.

CONCLUSION

GF, DM, and PSS were predictors for the recovery of PLA patients treated with PCD and antibiotics. The nomogram was effective in predicting the ORT of combination therapy.

A Nationwide Screen of Carbapenem-Resistant Klebsiella pneumoniae Reveals an Isolate with Enhanced Virulence and Clinically Undetected Colistin Heteroresistance

The convergence of hypervirulence and multidrug resistance in Klebsiella pneumoniae is a significant concern. Here, we report the first screen for hypermucoviscosity, a trait associated with increased virulence, using a U.S. surveillance collection of carbapenem-resistant (CR) K. pneumoniae isolates. We identified one hypermucoviscous isolate, which carried a gene encoding the KPC-3 carbapenemase, among numerous resistance genes. The strain further exhibited colistin heteroresistance undetected by diagnostics. This convergence of diverse resistance mechanisms and increased virulence underscores the need for enhanced K. pneumoniae surveillance.

Metabolic Characterization of Peripheral Host Responses to Drainage-Resistant Klebsiella pneumoniae Liver Abscesses by Serum 1H-NMR Spectroscopy

Purpose: To explore the metabolic characterization of host responses to drainage-resistant Klebsiella pneumoniae liver abscesses (DRKPLAs) with serum 1H-nuclear magnetic resonance (NMR) spectroscopy.

Materials and Methods: The hospital records of all patients with a diagnosis of a liver abscess between June 2015 and December 2016 were retrieved from an electronic hospital database. Eighty-six patients with Klebsiella pneumoniae (K. pneumoniae) liver abscesses who underwent percutaneous drainage were identified. Twenty patients with confirmed DRKPLAs were studied. Moreover, we identified 20 consecutive patients with drainage-sensitive Klebsiella pneumoniae liver abscesses (DSKPLAs) as controls. Serum samples from the two groups were analyzed with 1H NMR spectroscopy. Partial least squares discriminant analysis (PLS-DA) was used to perform 1H NMR metabolic profiling. Metabolites were identified using the Human Metabolome Database, and pathway analysis was performed with MetaboAnalyst 3.0.

Results: The PLS-DA test was able to discriminate between the two groups. Five key metabolites that contributed to their discrimination were identified. Glucose, lactate, and 3-hydroxybutyrate were found to be upregulated in DRKPLAs, whereas glutamine and alanine were downregulated compared with the DSKPLAs. Pathway analysis indicated that amino acid metabolisms were significantly different between the DRKPLAs and the DSKPLAs. The D-glutamine and D-glutamate metabolisms exhibited the greatest influences.

Conclusions: The five key metabolites identified in our study may be potential targets for guiding novel therapeutics of DRKPLAs and are worthy of additional investigation.

Gas-forming pyogenic liver abscess: A world review

BACKGROUNDS/AIMS

Gas-forming pyogenic liver abscess (GFPLA) has an incidence of up to 30% of all pyogenic liver abscesses (PLA). GFPLA has higher mortality compared to non-GFPLA. Mere presence of gas within abscess may not determine clinical outcome. Hence it is important to study biologic characteristics that make GFPLA a distinct clinical entity. The aim of this study was to conduct a world review on GFPLA.

METHODS

We conducted literature searches in PubMed using the following MeSH terms: "gas forming" AND "Liver abscess, pyogenic", "gas" AND "Liver abscess, pyogenic", "gas" AND "Liver abscess", "gas forming" AND "Liver abscess". Thirteen case series including 313 GFPLA patients were included. Age, gender, diabetes mellitus (DM), bacteriology, underlying etiology, symptoms, investigations, operative indications, and mortality rates were tabulated.

RESULTS

GFPLA is often cryptogenic. There was no difference in age, gender, or symptomatology between GFPLA and non-GFPLA patients. DM was more common in patients with GFPLA compared to that in non-GFPLA patients (mean: 83.5% vs. 38.3%). Klebsiella pneumoniae is the most common causative pathogen. GFPLA has higher mortality compared to non-GFPLA (mean: 30.3% vs. 9%).

CONCLUSIONS

GFPLA is associated with DM and monomicrobial Klebsiella pneumoniae infection. GFPLA has high mortality. It needs to be recognized as a distinct clinical entity.

A Klebsiella pneumoniae liver abscess presenting with myasthenia and tea-colored urine: A case report and review of 77 cases of bacterial rhabdomyolysis

RATIONALE

Rhabdomyolysis is a well-known syndrome in clinical practice, although rhabdomyolysis caused by a liver abscess is rarely reported and the patient may lack symptoms that are associated with a primary site of infection. Early recognition of this possibility is needed to avoid diagnostic delay and facilitate treatment. We report the case of a 71-year-old woman with a Klebsiella pneumoniae (KP) pyogenic liver abscess who presented with myasthenia and tea-colored urine and also review the 77 reported cases of bacterial rhabdomyolysis.

PATIENT CONCERNS

The patient was 71 years old and presenting with a 7-day history of myasthenia and a 3-day history of tea-colored urine, but without fever or abdominal pain.

DIAGNOSES

Laboratory testing in our case revealed rhabdomyolysis, and blood culture revealed KP. Abdominal ultrasonography revealed a hypoechoic enclosed mass, and computed tomography (CT) revealed an enclosed low-density mass (8.3 × 6.6 × 6.1 cm). The main diagnoses were a pyogenic liver abscess with rhabdomyolysis.

INTERVENTIONS

Empirically intravenous piperacillin-sulbactam and intravenous potassium treatment, as well as fluid infusions and other supportive treatments were provided after admission. After the diagnosis was confirmed and susceptibility test results were available, we adjusted the antibiotics to cefoperazone and sulbactam, which were maintained for 6 weeks.

OUTCOMES

The patient's symptoms relieved and the abnormal laboratory parameters corrected. Follow-up abdominal ultrasonography at 24 months after her discharge revealed that the abscess had disappeared.

LESSONS

Early recognition and careful consideration of the underlying cause of rhabdomyolysis are critical to improving the patient's prognosis. Thus, physicians should carefully consider the underlying cause in elderly patients who present with rhabdomyolysis, as they may lack symptoms of a primary infection.

Antimicrobial Resistance of Hypervirulent Klebsiella pneumoniae: Epidemiology, Hypervirulence-Associated Determinants, and Resistance Mechanisms

Klebsiella pneumoniae is one of the most clinically relevant species in immunocompromised individuals responsible for community-acquired and nosocomial infections, including pneumonias, urinary tract infections, bacteremias, and liver abscesses. Since the mid-1980s, hypervirulent K. pneumoniae, generally associated with the hypermucoviscosity phenotype, has emerged as a clinically significant pathogen responsible for serious disseminated infections, such as pyogenic liver abscesses, osteomyelitis, and endophthalmitis, in a generally younger and healthier population. Hypervirulent K. pneumoniae infections were primarily found in East Asia and now are increasingly being reported worldwide. Although most hypervirulent K. pneumoniae isolates are antibiotic-susceptible, some isolates with combined virulence and resistance, such as the carbapenem-resistant hypervirulent K. pneumoniae isolates, are increasingly being detected. The combination of multidrug resistance and enhanced virulence has the potential to cause the next clinical crisis. To better understand the basic biology of hypervirulent K. pneumoniae, this review will provide a summarization and discussion focused on epidemiology, hypervirulence-associated factors, and antibiotic resistance mechanisms of such hypervirulent strains. Epidemiological analysis of recent clinical isolates in China warns the global dissemination of hypervirulent K. pneumoniae strains with extensive antibiotic resistance in the near future. Therefore, an immediate response to recognize the global dissemination of this hypervirulent strain with resistance determinants is an urgent priority.

First case report of non-human primates (Alouatta clamitans) with the hypervirulent Klebsiella pneumoniae serotype K1 strain ST 23: A possible emerging wildlife pathogen

BACKGROUND

Hypervirulent strain of Klebsiella pneumoniae genotype K1 isolates have recently emerged, causing severe pyogenic liver abscess complicated by devastating metastatic infections in humans.

METHODS

We describe a short outbreak of the non-human primate (NHP) research center, associated with a hypervirulent K. pneumoniae. The genetic similarity of the strains was evaluated by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) techniques, and virulence encoding genes were detected by polymerase chain reaction (PCR).

RESULTS

The isolates were phenotypically like strains causing community-acquired invasive liver abscess syndrome in humans. All strains exhibited identical PFGE patterns and were found to belong to ST23 and presented a hypermucovisity phenotype and possessed magA and rmpA gene.

CONCLUSION

This is the first case report of NHPs caused by K. pneumoniae displaying a hypermucoviscosity phenotype and belonging to capsular serotypes K1 and ST23.

Metastatic endophthalmitis and thyroid abscess complicating Klebsiella pneumoniae liver abscess

The thyroid is resistant to infection due to its anatomical and physiological characteristics. We present a rare case of invasive liver abscess with metastatic thyroid abscess and endogenous endophthalmitis in a previously healthy 55-year-old female patient without diabetes or other medical illness. This report raises an important question of the virulence of Klebsiella pneumoniae as an increasingly common causative agent of liver abscess.

Klebsiella pneumoniae invasive liver abscess syndrome with purulent meningitis and septic shock: A case from mainland China

We present a rare case of invasive liver abscess syndrome due to Klebsiella pneumoniae (K. pneumoniae) with metastatic meningitis and septic shock. A previously healthy, 55-year-old female patient developed fever, liver abscess, septic shock, purulent meningitis and metastatic hydrocephalus. Upon admission, the clinical manifestations, laboratory and imaging examinations were compatible with a diagnosis of K. pneumoniae primary liver abscess. Her distal metastasis infection involved meningitis and hydrocephalus, which could flare abruptly and be life threatening. Even with early adequate drainage and antibiotic therapy, the patient’s condition deteriorated and she ultimately died. To the best of our knowledge, this is the first case of K. pneumoniae invasive liver abscess syndrome with septic meningitis reported in mainland China. Our findings reflect the need for a better understanding of the epidemiology, risk factors, complications, comorbid medical conditions and treatment of this disease.

Increased Risk of Pyogenic Liver Abscess Among Patients With Colonic Diverticular Diseases: A Nationwide Cohort Study

Whether patients with diverticular diseases exhibit a higher risk of developing pyogenic liver abscess (PLA) remains inconclusive.From the inpatient claims in Taiwan's National Health Insurance Research Database, we identified 54,147 patients diagnosed with diverticulosis in the 1998 to 2010 period and 216,588 controls without the disorder. The 2 cohorts were matched by age, sex, and admission year, and were followed up until the end of 2010 to estimate the risk of PLA.Overall, the incidence of PLA was 2.44-fold higher in the diverticular-disease group than in the controls (11.5 vs 4.65 per 10,000 person-year). The adjusted hazard ratio (aHR) of PLA was 2.11 (95% confidence interval [CI], 1.81-2.44) for the diverticular-disease group, according to a multivariate Cox proportional hazards regression model. The age-specific data showed that the aHR for the diverticular-disease group, compared with the controls, was the highest inpatients younger than 50 years old (aHR, 4.03; 95% CI, 2.77-5.85). Further analysis showed that the diverticular-disease group exhibited an elevated risk of PLA regardless of whether patients had diverticulitis.The patients with diverticular diseases exhibited a higher risk of PLA.

Emergence of Carbapenem-Resistant Serotype K1 Hypervirulent Klebsiella pneumoniae Strains in China

We report the emergence of five carbapenem-resistant K1 hypervirulent Klebsiella pneumoniae (hvKP) strains which caused fatal infections in hospital patients in Zhejiang Province, China, upon entry through surgical wounds. Genotyping results revealed the existence of three genetically related strains which exhibited a new sequence type, ST1797, and revealed that all strains harbored the magA and wcaG virulence genes and a plasmid-borne bla(KPC-2) gene. These findings indicate that K1 hvKP is simultaneously hypervirulent, multidrug resistant, and transmissible.

Molecular epidemiology and virulence factors of pyogenic liver abscess causing Klebsiella pneumoniae in China

The molecular epidemiology and prevalence of virulence factors of isolates from patients with Klebsiella pneumoniae liver abscess (KLA) in mainland China are unknown. Klebsiella pneumoniae isolates were obtained from drainage samples aseptically collected from patients with pyogenic liver abscess (PLA). The genetic similarity of KLA isolates was analyzed by pulsed-field gel electrophoresis. The hypermucoviscosity (HV) phenotype was identified by a positive string test. The K1 and K2 genotypes, the pLVPK-derived genetic loci, aerobactin gene, kfu and alls were detected by PCR amplification. The sequence types (STs) were identified by multilocus sequence typing. Among the 51 non-repetitive KLA isolates, 49 PFGE types have been identified. In total, 19 (37.2%) and 14 (27.4%) of the 51 KLA isolates belonged to clonal complex (CC) 23 and CC65, respectively, while the other 18 isolates (35.3%) were defined as other STs. CC23 consisted of only K1 strains, while CC65 included only K2 strains. All non-K1/K2 strains were classified as STs other than CC23 and CC65. Approximately 70.6% (36/51) of KLA isolates exhibited an HV phenotype. Both K1 and K2 isolates presented significantly higher prevalence of the pLVPK-derived loci than non-K1/K2 isolates. The K1 isolates had a significantly higher prevalence of the kfu and allS genes than K2 and non-K1/K2 isolates, while the K2 isolates exhibited higher repA prevalence than K1 and non-K1/K2 isolates. The majority of KLA isolates belonged to CC23K1 and CC65K2, while other STs with non-K1/K2 capsular types have also been identified. The virulent factors exhibited diverse distribution among the different clones of KLA isolates.

Occult pyogenic liver abscess in an adolescent with type 2 diabetes

Pyogenic liver abscess is a rare complication of diabetes, usually seen in adults greater than 50 years of age who have had diabetes for many years. We describe an 18-year-old male with type 2 diabetes found to have a pyogenic liver abscess caused by Klebsiella pneumoniae, and show accompanying images from his evaluation for fever of unknown origin (FUO). We conclude that in a child or adolescent with FUO and diabetes, occult pyogenic liver abscess must be considered.