Long-term mortality of patients with septic ocular or central nervous system complications from pyogenic liver abscess: a population-based study

Literature- and Experience-Based Consensus for Acute Post-operative Endophthalmitis and Endogenous Endophthalmitis in Taiwan

Clinical practices on acute post-operative and endogenous endophthalmitis (EnE) are highly variable among clinicians due to a lack of up-to-date, high-quality evidential support. An expert consensus is thus much needed. A panel consisting of ten retinal specialists in Taiwan was organized. They evaluated relevant literature and developed key questions regarding acute post-operative and EnE that are cardinal for practice but yet to have conclusive evidence. The panel then attempted to reach consensus on all the key questions accordingly. There were eight key questions proposed and their respective consensus statements were summarized as follows: Gram staining and culture are still the standard procedures for the diagnosis of endophthalmitis. Vitrectomy is recommended to be performed earlier than the timing proposed by the Endophthalmitis Vitrectomy Study (EVS). Routine intracameral antibiotic injection for post-cataract surgery endophthalmitis prophylaxis is not recommended because of potential compounding error hazards and a lack of support from high-quality studies. Routine fundus examination is recommended for all patients with pyogenic liver abscess. In EnE, vitrectomy is recommended if diffused and dense vitritis is present, or if the disease progresses. These consensus statements may work as handy guidance or reference for clinical practices of acute post-operative and EnE.

Microevolution of CG23-I Hypervirulent Klebsiella pneumoniae during Recurrent Infections in a Single Patient

CG23-I lineage constitutes the majority of hypervirulent Klebsiella pneumoniae. A diabetic patient suffered six episodes of infections caused by CG23-I K. pneumoniae. A total of nine isolates were collected in 2020. We performed whole-genome sequencing to elucidate the within-patient evolution of CG23-I K. pneumoniae. The maximum pairwise difference among the nine longitudinally collected isolates was five single nucleotide polymorphisms. One of the mutations was at the Asp87 position of GyrA. Four indels were identified, including an initiator tRNAfMet duplication, a tRNAArg deletion, a 7-bp insertion, and a 22-bp deletion. All 9 isolates had the genomic features of CG23-I K. pneumoniae, a chromosome-borne ICEKp10, and a large virulence plasmid. The carriage of a complete set of genes for the biosynthesis of colibactin by ICEKp10 gave the nine isolates an ability to cause DNA damage to RAW264.7 cells. Compared with the initial isolate, the last isolate with an additional copy of initiator tRNAfMet grew faster in a nutrient-limiting condition and exhibited enhanced virulence in BALB/c mice. Collectively, we characterized the within-patient microevolution of CG23-I K. pneumoniae through an in-depth comparison of genome sequences. Using the in vitro experiments and mouse models, we also demonstrated that these genomic alterations endowed the isolates with advantages to pass through in vivo selection. IMPORTANCE CG23-I is a significant lineage of hypervirulent Klebsiella pneumoniae. This study characterizes the within-patient microevolution of CG23-I K. pneumoniae. Selective pressures from continuous use of antibiotics favored point mutations contributing to bacterial resistance to antibiotics. The duplication of an initiator tRNAfMet gene helped CG23-I K. pneumoniae proliferate to reach a maximal population size during infections. For longer persistence inside a human host, the large virulence plasmid evolved with more flexible control of replication through duplication of the iteron-1 region. With the genomic alterations, the last isolate had a growth advantage over the initial isolate and exhibited enhanced virulence in BALB/c mice. This study gives us a deeper understanding of the genome evolution during the within-patient pathoadaptation of CG23-I K. pneumoniae.

Klebsiella pneumoniae liver abscess with purulent meningitis and endogenous endophthalmitis: A case report

This is a rare but typical case of a Klebsiella pneumoniae liver abscess with migratory infections including purulent meningitis and endogenous endophthalmitis. The patient had a chief complaint of 7 days of fever, 4 days of blurry vision, and 4 h of glossolalia. Ultrasound scan and computed tomography (CT) suggested a liver abscess. Both blood and drainage fluid cultures grew K. pneumoniae with a high mucosal phenotype. The patient was finally diagnosed with a K. pneumoniae liver abscess, purulent meningitis, and endogenous K. pneumoniae endophthalmitis in the right eye. Ultrasound-guided percutaneous catheter drainage (PCD) of the liver abscess was performed, and meropenem was used to control infection. The patient was given 0.1 ml of vancomycin (10 g/L) and 0.1 ml of ceftazidime (20 g/L) were by intravitreal injection for the treatment of endophthalmitis. The infection was gradually controlled after such treatments. The patient was discharged from our hospital with an improved condition. However, during the time of follow-up, she developed complications due to severe pneumonia and eventually died in a local hospital. This case revealed that a rapid diagnosis followed by appropriate treatment would improve prognosis and prevent severe metastatic complications.

Metagenome Analysis of the Bacterial Characteristics in Invasive Klebsiella Pneumoniae Liver Abscesses

Background

Klebsiella pneumoniae liver abscess (KPLA) combined with extrahepatic migratory infection (EMI) is defined as invasive KPLA (IKPLA) and is associated with a poor prognosis. The mechanism of IKPLA formation is yet to be elucidated. In this study, metagenomic sequencing was used to compare the bacterial characteristics between IKPLA and KPLA to explore the underlying mechanism of invasiveness.

Methods

Clinical details, imaging, and microbial features were retrospectively evaluated by medical record review. Metagenomic sequencing was performed on the pus samples of liver abscesses whose culture results were indicative of monomicrobial Klebsiella pneumoniae (K. pneumoniae). Bacterial diversity and composition in IKPLA and KPLA were comparatively analyzed, and the key pathways and genes that may affect invasiveness were further explored.

Results

Sixteen patients were included in this study. Five patients with EMI were included in the IKPLA group, and the other eleven patients without EMI were assigned to the KPLA group. There was no statistical difference in the hypermucoviscous phenotype and serotype of K. pneumoniae between the two groups. The bacterial diversity of IKPLA was lower than that of KPLA. The abundant taxa in the IKPLA group were primarily species of unclassified Enterobacteriaceae and K. pneumoniae. The KPLA group had a high abundance of the genera Tetrasphaera and Leuconostoc. Metabolic pathway genes represented most of the enriched genes in IKPLA. Fourteen pathogenic genes with significant differences in abundance were identified between the two groups, including ybtS, fepC, phoQ, acrB, fimK, magA, entC, arnT, iucA, fepG, oqxB, entA, tonB, and entF (p < 0.001).

Conclusion

The diversity and bacterial composition of IKPLA were significantly different from those of KPLA. Microbiological changes in the abscess, activation of the related metabolic pathways, and the pathogenic gene expression may constitute a novel mechanism that regulates the invasiveness of KPLA.

Clinical features and development of Sepsis in Klebsiella pneumoniae infected liver abscess patients: a retrospective analysis of 135 cases

Background

Klebsiella pneumoniae is a primary pathogen of pyogenic liver abscess (PLA). However, little data are available on combination with sepsis. In this study, we aimed to evaluate the clinical characteristics and prognostic differences of PLA patients with sepsis.

Methods

This retrospective cohort study was conducted to investigate 135 patients with confirmed Klebsiella pneumoniae-caused liver abscesses (KPLA) from a tertiary teaching hospital, from 2013 to 2019. The patients were divided into two groups, KPLA with sepsis and KPLA without sepsis. The demographic characteristics, clinical features as well as laboratory and microbiologic findings were analyzed.

Results

A total of 135 patients with KPLA were analyzed. The mean age of patients was 60.9 ± 12.7 years, and the percentage of men was 59.3%. Among them, 37/135 (27.4%) of patients had sepsis and the mortality rate was 1.5%. The most common symptom was fever (91.1%). KPLA patients with sepsis had a significantly higher proportion of frailty, diarrhea, fatty liver, chronic renal insufficiency, and hepatic dysfunction compared to KPLA patients without sepsis (p < 0.05). Antibiotic therapy and percutaneous drainage were most frequently therapeutic strategy. Furthermore, the incidences of sepsis shock and acute respiratory distress syndrome were higher in the sepsis group compared to the non-sepsis group. As for metastatic infections, the lung was the most common site. In addition, KPLA patients with sepsis showed respiratory symptoms in 11 patients, endophthalmitis in 4 patients, and meningitis in 1 patient.

Conclusion

Our findings emphasize that KPLA patients combined with or without sepsis have different clinical features, but KPLA patients with sepsis have higher rates of complications and metastatic infections. Taken together, further surveillance and control of septic spread is essential for KPLA patients.

Analysis of the clinical characteristics of 202 patients with liver abscess associated with diabetes mellitus and biliary tract disease

OBJECTIVE

Clinical characteristics of patients with pyogenic liver abscess (PLA) of varying etiologies may be different. This study aimed to analyze the clinical characteristics, pathogenic bacteria, treatment, and prognosis of patients with PLA associated with diabetes and biliary disease.

METHODS

Clinical, imaging, and laboratory data from 202 inpatients with PLA were retrospectively analyzed.

RESULTS

Eighty-eight patients (43.6%) had a history of diabetes, 73 (36.1%) had a history of underlying biliary tract disease, and 24 (11.9%) had both the diseases. The level of C-reactive protein (CRP) increased in 99.2% (119/120) patients, and the level of procalcitonin (PCT) increased in 95.5% (148/155) patients. The main pathogen of PLA was Klebsiella pneumoniae. The incidence of bloodstream infection increased by 34.4% (22/64) in patients with PLA that was associated with diabetes mellitus, and that of K. pneumoniae infection was 88.6% (39/44). The readmission rate for patients with PLA with underlying biliary diseases was 10.2 to 12.5%.

CONCLUSION

The main pathogen of PLA is K. pneumoniae, which is sensitive to most antibiotics. Patients with PLA associated with diabetes were more likely to have bloodstream infections, and the recurrence rate of PLA with underlying biliary diseases was higher than without biliary duct disease.

Pyogenic Liver Abscess Risk in Patients With Newly Diagnosed Type 2 Diabetes Mellitus: A Nationwide, Population-Based Cohort Study

Background: To date, no comprehensive epidemiological study exists on pyogenic liver abscess (PLA) risk in patients with newly diagnosed type 2 diabetes mellitus (T2DM) worldwide. Methods: We conducted a retrospective cohort study by using data from Taiwan National Health Insurance Research Database (NHIRD) to examine the association between newly diagnosed T2DM and PLA. The T2DM cohort included patients newly diagnosed as having T2DM (ICD-9-CM:250) from 2000 to 2009, with follow-up until December 31, 2011. The comparison cohort was then recruited through 1:4 random frequency matching with the T2DM cohort. Finally, the adjusted hazard ratios for PLA were compared between the T2DM and comparison cohorts, which included 44,728 patients with T2DM and 178,912 patients without DM respectively. Results: In T2DM cohort, 166 patients were diagnosed as having PLA (incidence rate = 5.87 per 10,000 person-years) and in comparison cohort, 238 patients were diagnosed as having PLA (incidence rate = 2.06 per 10,000 person-years). The T2DM cohort exhibited higher PLA risk than did the comparison cohort (hazard ratio = 2.83, 95% confidence interval = 2.32-3.46). Furthermore, the adjusted hazard ratio for PLA risk in T2DM cohort was the highest in those who were younger, man and with duration of DM <2 years. In the T2DM cohort, the most common PLA causative agent was Klebsiella pneumonia (KP). In addition, PLA risk was high in T2DM patients with gallstone and cholecystitis. Compared with comparison cohort, patients with T2DM prescribed acarbose has a lower PLA risk, however glyburide significantly increased PLA risk in T2DM cohort. Conclusion: In patients with newly diagnosed T2DM, PLA risk was high and acarbose might reduce PLA risk.

Klebsiella pneumoniae-related invasive liver abscess syndrome complicated by purulent meningitis: a review of the literature and description of three cases

Background

Klebsiella pneumoniae (K. pneumoniae) invasive liver abscess syndrome (ILAS) with purulent meningitis was rarely identified the mainland of China. Last winter, we received 3 cases of K. pneumoniae meningitis and all of them died in a short time. We report these cases in order to find the reason of high mortality and discuss effective effort to improve these patients’ prognosis.

Case presentation

Three patients with uncontrolled diabetes developed live abscess and purulent meningitis. Upon admission, the clinical manifestations, laboratory result of blood and cerebrospinal fluid (CSF) and imaging examinations were compatible with K. pneumoniae ILAS which had metastasis infection of meningitis. Even with timely adequate antibiotic therapy and strict glycemic control, all of the patients’ condition deteriorated rapidly and died in a short time.

Conclusion

The reason of patients’ poor prognosis might be the absence of liver abscess drainage, high level of CSF protein which indicates severe inflammation and unknown special but stronger virulence factors of K. pneumoniae the patients’ living place Zhangjiakou. Strict glycemic control, early drainage of liver abscess and appropriate antibiotic application are recommended for treating this condition, further progress on the pathogenesis and treatment of K. pneumoniae meningitis may help patients gain a better prognosis.

Clinical Features and Prognosis of Gas-Forming and Non-Gas-Forming Pyogenic Liver Abscess: A Comparative Study

Background: Gas-forming pyogenic liver abscess (GFPLA) accounts for up to 30% of all pyogenic liver abscess (PLA) cases. However, little is known of the differences in clinical features and prognosis between GFPLA and non-GFPLA. Aim: This retrospective study compared the clinical features and prognosis of GFPLA and non-GFPLA. Patients and Methods: Data for 392 patients with PLA treated from January 1, 2007 to December 31, 2016 were reviewed. Gas-forming pyogenic liver abscess was defined as gas in the abscess. Liver abscesses were considered non-GFPLA (n = 326) or GFPLA (n = 66). The clinical features and outcomes of patients with GFPLA were compared with that of patients without GFPLA. Results: The groups were similar in gender ratio, age, smoking, drinking, and comorbidities. Klebsiella pneumoniae was the most common pathogenic bacteria, but the negative rate of bacterial culture of the non-GFPLA group was higher than that of the GFPLA. In etiologies, the GFPLA group had more biliary source infection and less cryptogenic infection. In addition, the GFPLA group had a higher rate of previous hepatobiliary surgery, especially biliary enteric anastomosis. Compared with the non-GFPLA group, the percentage of the GFPLA group with antibiotic agents combined with percutaneous drainage was higher, whereas the percentages given antibiotic agents alone and antibiotic agents combined with surgical drainage were lower. Patients with GFPLA had higher rates of sepsis and pleural effusion, and longer hospital stays than did non-GFPLA patients. No patient died during hospitalization. Conclusions: The GFPLA group had more biliary source infection and less cryptogenic infection in etiologies. Gas-forming pyogenic liver abscess is associated with past hepatobiliary surgery, especially biliary enteric anastomosis and has high rates of sepsis and long hospitalization. Thus, the patients with PLA with a history of hepatobiliary surgery should be monitored more closely in the early stage of the PLA. It needs to be recognized as a distinct clinical entity.

Fluoroquinolones as an alternative treatment for Klebsiella pneumoniae liver abscess and impact on hospital length of stay

Klebsiella pneumoniae liver abscess (KPLA) is an endemic disease in East Asia. Patients with KPLA usually require prolonged intravenous (i.v.) β-lactam therapy and hospitalisation. Fluoroquinolones have high oral bioavailability and the potential to shorten the duration of i.v. therapy. The aim of this study was to investigate the feasibility of fluoroquinolones as an alternative treatment for KPLA in Taiwan. Consecutive patients with KPLA in a medical centre in Taiwan between July 2012 and August 2019 were retrospectively enrolled. Clinical characteristics and outcomes were compared between cases treated with β-lactams and fluoroquinolones. A multivariate logistic regression model and propensity-score adjusted analysis were performed to identify independent risk factors for prolonged hospitalisation. A total of 234 patients with KPLA were identified during the study period. Most patients received β-lactams (n = 199; 85.0%), whilst only 35 (15.0%) received fluoroquinolones as the major therapy. Fluoroquinolones had similar clinical efficacy to β-lactams even in critically ill patients. Patients treated with fluoroquinolones had a shorter i.v. antibiotics duration (18.9 ± 7.6 days vs. 28.5 ± 14.7 days; P < 0.001) and hospital length of stay (LOS) (20.9 ± 8.3 days vs. 29.5 ± 16.2 days; P < 0.001) than patients treated with β-lactams. Major therapy with fluoroquinolones was an independent protective factor for hospital LOS > 14 days in all patients and for hospital LOS > 21 days in critically ill patients. In conclusion, fluoroquinolones were an effective alternative treatment for KPLA that resulted in a shorter duration of i.v. therapy and hospital LOS.

Molecular and Clinical Characterization of Multidrug-Resistant and Hypervirulent Klebsiella pneumoniae Strains from Liver Abscess in Taiwan

Hypervirulent Klebsiella pneumoniae strains are the major cause of liver abscesses throughout East Asia, and these strains are usually antibiotic susceptible. Recently, multidrug-resistant and hypervirulent (MDR-HV) K. pneumoniae strains have emerged due to hypervirulent strains acquiring antimicrobial resistance determinants or the transfer of a virulence plasmid into a classic MDR strain. In this study, we characterized the clinical and microbiological properties of K. pneumoniae liver abscess (KPLA) caused by MDR-HV strains in Taiwan. Patients with community onset KPLA were retrospectively identified at Taipei Veterans General Hospital during January 2013 to May 2018. Antimicrobial resistance mechanisms, capsular types, and sequence types were determined. MDR-HV strains and their parental antimicrobial-susceptible strains further underwent whole-genome sequencing (WGS) and in vivo mice lethality tests. Thirteen MDR-HV strains were identified from a total of 218 KPLA episodes. MDR-HV strains resulted in similar outcomes to antimicrobial-susceptible strains. All MDR-HV strains were traditional hypervirulent clones carrying virulence capsular types. The major resistance mechanisms were the overexpression of efflux pumps and/or the acquisition of ESBL or AmpC β-lactamase genes. WGS revealed that two hypervirulent strains had evolved to an MDR phenotype due to mutation in the ramR gene and the acquisition of an SHV-12-bearing plasmid, respectively. Both these MDR-HV strains retained high virulence compared to their parental strains. The spread of MDR-HV K. pneumoniae strains in the community raises significant public concerns, and measures should be taken to prevent the further acquisition of carbapenemase and other resistance genes among these strains in order to avoid the occurrence of untreatable KPLA.

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.

Hypervirulent Klebsiella pneumoniae

Hypervirulent K. pneumoniae (hvKp) is an evolving pathotype that is more virulent than classical K. pneumoniae (cKp). hvKp usually infects individuals from the community, who are often healthy. Infections are more common in the Asian Pacific Rim but are occurring globally. hvKp infection frequently presents at multiple sites or subsequently metastatically spreads, often requiring source control. hvKp has an increased ability to cause central nervous system infection and endophthalmitis, which require rapid recognition and site-specific treatment. The genetic factors that confer hvKp's hypervirulent phenotype are present on a large virulence plasmid and perhaps integrative conjugal elements. Increased capsule production and aerobactin production are established hvKp-specific virulence factors. Similar to cKp, hvKp strains are becoming increasingly resistant to antimicrobials via acquisition of mobile elements carrying resistance determinants, and new hvKp strains emerge when extensively drug-resistant cKp strains acquire hvKp-specific virulence determinants, resulting in nosocomial infection. Presently, clinical laboratories are unable to differentiate cKp from hvKp, but recently, several biomarkers and quantitative siderophore production have been shown to accurately predict hvKp strains, which could lead to the development of a diagnostic test for use by clinical laboratories for optimal patient care and for use in epidemiologic surveillance and research studies.

Epidemiology and Mortality-Related Prognostic Factors in Endophthalmitis

Purpose

Endophthalmitis describes any intraocular inflammation that involves both the posterior and anterior segments and is divided into endogenous and exogenous types according to its pathogenesis. The incidence of endophthalmitis and its risk factors have been extensively evaluated. However, few studies have explored the mortality rate in patients diagnosed with endophthalmitis.

Methods

We obtained data entered into the National Health Insurance Research Database (NHIRD) from 2000 to 2013. The data collected included all discharge diagnoses of endophthalmitis in inpatients. Baseline characteristics, comorbidities, and prognostic factors were evaluated.

Results

This study identified 7764 patients who were diagnosed with endophthalmitis in Taiwan from 2000 to 2013. The mortality rate was 0.97% (75/7764), and the mean age was 63.57 ± 15.72 years. Epidemiological characteristics were compared as "with or without" for different systemic comorbidities, and the results indicated that the adjusted odds ratio (AOR) was significantly higher in cases comorbid with renal disease (AOR 2.864, P = 0.001), septicemia (AOR 8.886, P < 0.001), pneumonia (AOR 2.072, P = 0.030), and tumors (AOR 7.437, P < 0.001). However, comorbidity with diabetes mellitus (DM) lowered the AOR by 0.500-fold (P = 0.026). There was no significant difference in ORs between patients comorbid with hypertension, depression, anxiety, hyperlipidemia, thyrotoxicosis, liver disease, or injury (all P > 0.05).

Conclusions

Among inpatients with endophthalmitis, predictors of mortality include renal disease, septicemia, pneumonia, neoplasia, a greater burden of comorbidity (especially catastrophic illness), longer hospital stays (more than 11 days), and higher medical costs. Interestingly, DM decreased the OR for inpatient mortality.

High mortality among patients infected with hypervirulent antimicrobial-resistant capsular type K1 Klebsiella pneumoniae strains in Taiwan

Capsular type K1 Klebsiella pneumoniae, highly virulent strains which are common in Asian countries, can cause pyogenic infections. These hypervirulent strains are usually susceptible to most antimicrobials, except for ampicillin. Little is known regarding the clinical and molecular characteristics of antimicrobial-resistant K1 K. pneumoniae strains. This retrospective study evaluated patients infected with capsular type K1 K. pneumoniae strains in a Taiwanese medical centre between April 2013 and March 2016. Antimicrobial-resistant strains were defined based on non-susceptibility to antimicrobial agents except ampicillin. We compared the clinical outcome of patients infected with and without antimicrobial-resistant strains. The in vivo virulence, genetic relatedness, and resistance mechanisms of these hypervirulent antimicrobial-resistant strains were also investigated. A total of 182 capsular type K1 K. pneumoniae strains were identified, including 18 antimicrobial-resistant strains. The 28-day mortality rate among the 18 cases caused by antimicrobial-resistant strains was significantly higher than that among 164 cases caused by antimicrobial-sensitive strains (50% vs. 10.4%, P < 0.001). Infection with antimicrobial-resistant strain independently increased the 28-day mortality risk. Most antimicrobial-resistant strains were not clonally related, and they exhibited high in vivo virulence in a mouse lethality experiment. The major resistance mechanisms involved the presence of β-lactamases and the overexpression of efflux pumps. In conclusion, hypervirulent antimicrobial-resistant capsular type K1 K. pneumoniae strains can predispose to a fatal outcome. These strains may represent an emerging threat to public health in Taiwan.

Pneumonia is an independent risk factor for pyogenic liver abscess: A population-based, nested, case-control study

Background

Bacteremic pneumonia is considered a potential cause of distal organ abscess formation. Therefore, we hypothesize that pneumonia is a risk factor for pyogenic liver abscess (PLA).The aim of this study is to explore the association between pneumonia and PLA.

Methodology/Principal findings

A nationwide, population-based, nested, case–control study was conducted using data from the Taiwan National Health Insurance Research Database. In total, 494 patients with PLA and 1,976 propensity score matched controls were enrolled. Conditional logistic regression was used to estimate adjusted odds ratios (aORs) in patients with exposure to pneumonia before PLA. After matched and adjusted for confounding factors including age, sex, urbanization, income, chronic liver disease, alcohol-related disease, biliary stone, chronic kidney disease, diabetes mellitus, chronic liver disease, and cancer, hospitalization for pneumonia remained an independent risk factor for PLA with an aORs of 2.104 [95% confidence interval (CI) = 1.309–3.379, p = 0.0021]. Moreover, the aORs were significantly higher among patients hospitalized for pneumonia within 30 days (aORs = 10.73, 95% CI = 3.381–34.054), 30–90 days (aORs = 4.698, 95% CI = 1.541–14.327) and 90–180 (aORs = 4.000, 95% CI = 1.158–13.817) days before PLA diagnosis.

Conclusion

Pneumonia is an independent risk factor for subsequent PLA. Moreover, hospitalization for pneumonia within 180 days before PLA diagnosis was associated with an increased risk of PLA.

Recent upper gastrointestinal panendoscopy increases the risk of pyogenic liver abscess

AIM

To investigate the association between a recent gastrointestinal (GI) endoscopy and the subsequent risk of pyogenic liver abscess (PLA).

METHODS

We designed a nested case control study. Using the Taiwan National Health Insurance Research Database, 2135 patients with a first diagnosis of PLA were identified from 1998 to 2011. Another 10675 patients without PLA matched by age and sex were selected as reference controls. We identified and compared the possible risk factors for PLA and GI endoscopies performed before the index date (when PLA was diagnosed) between the two cohorts. Multivariate analysis was conducted to examine the risk of PLA within the 90 d after the GI endoscopies.

RESULTS

Patients with a history of diabetes [adjusted odds ratio (aOR) = 4.92, 95%CI: 1.78-13.61], end-stage renal disease (aOR = 3.98, 95%CI: 1.45-10.91), biliary tract infection (aOR = 2.68, 95%CI: 2.11-3.40), liver cirrhosis (aOR = 2.19, 95%CI: 1.39-3.46), GI malignancies (aOR = 5.68, 95%CI: 4.23-7.64), appendicitis (aOR = 3.16, 95%CI: 2.27-4.41), diverticulitis (aOR = 1.64, 95%CI: 1.01-2.64), and recent endoscopic retrograde cholangiopancreatography (aOR = 27.04, 95%CI: 11.65-62.72) were significantly associated with an increased risk of PLA. After adjusting for the above risk factors and the frequency of outpatient department visits and abdominal ultrasounds during 90 d before the index date, an upper GI panendoscopy (aOR = 2.75, 95%CI: 2.05-3.69) but not a lower GI endoscopy (aOR = 1.07, 95%CI: 0.62-1.86) was significantly associated with PLA.

CONCLUSION

An upper GI panendoscopy performed before 90 d may increase the risk of PLA.

Two unusual cases of successful treatment of hypermucoviscous Klebsiella pneumoniae invasive syndrome

BACKGROUND

A few Japanese cases of hypermucoviscous Klebsiella pneumoniae (K. pneumoniae) invasive syndrome have recently been reported. Although extrahepatic complications from bacteremic dissemination have been observed, infected aneurysms are rare. Furthermore, the primary source of infection is generally a liver abscess, and is rarely the prostate. Therefore, we report two atypical cases of hypermucoviscous K. pneumoniae invasive syndrome.

CASE PRESENTATION

The first case was an 81-year-old Japanese man with no significant medical history, who was referred to our hospital for vision loss in his right eye. Contrast-enhanced whole-body computed tomography revealed abscesses in the liver and the prostate, and an infected left internal iliac artery aneurysm. Contrast-enhanced head magnetic resonance imaging revealed brain abscesses. Cultures of the liver abscess specimen and aqueous humor revealed K. pneumoniae with the hypermucoviscosity phenotype, which carried the magA gene (mucoviscosity-associated gene A) and the rmpA gene (regulator of mucoid phenotype A). We performed enucleation of the right eyeball, percutaneous transhepatic drainage, coil embolization of the aneurysm, and administered a 6-week course of antibiotic treatment. The second case was a 69-year-old Japanese man with diabetes mellitus, who was referred to our hospital with fever, pollakiuria, and pain on urination. Contrast-enhanced whole-body computed tomography revealed lung and prostate abscesses, but no liver abscesses. Contrast-enhanced head magnetic resonance imaging revealed brain abscesses. The sputum, urine, prostate abscess specimen, and aqueous humor cultures revealed K. pneumoniae with the hypermucoviscosity phenotype, which carried magA and rmpA. We performed enucleation of the left eyeball, percutaneous drainage of the prostate abscess, and administered a 5-week course of antibiotic treatment.

CONCLUSIONS

Hypermucoviscous K. pneumoniae can cause infected aneurysms, and the prostate can be the primary site of infection. We suggest that a diagnosis of hvKP invasive syndrome should be considered in all patients who present with K. pneumoniae infection and multiple organ abscesses.

The emergence of Klebsiella pneumoniae liver abscess in non-diabetic patients and the distribution of capsular types

Background

Klebsiella pneumoniae is the most common pathogen of community-acquired pyogenic liver abscess in East Asia. Diabetes mellitus (DM) is a well-established risk factor for K. pneumoniae liver abscess (KPLA). However, reports regarding the emergence of KPLA in non-diabetic patients are limited.

Results

A total 230 patients with KPLA from a medical center in Taiwan were identified retrospectively. The rate of DM in patients with KPLA was 44.4 % in 2011, 57.9 % in 2012, 44.9 % in 2013, 35.0 % in 2014, and 53.5 % in 2015. Diabetic patients had higher rate of gas-forming abscesses than non-diabetic patients, but the clinical outcomes were not different. The six virulent capsular types (K1, K2, K5, K20, K54, and K57) accounted for 90.2 % of all K. pneumoniae isolates, and were more prevalent in non-diabetic than diabetic patients (93.9 vs 85.9 %, P = 0.048). The six virulent capsular types were also more prevalent in the group with optimal glycemic levels (Non-DM and DM with HbA1c level <7 %) than the DM group with HbA1c level ≥7 % (93.9 vs 84.3 %, P = 0.022).

Conclusion

Klebsiella pneumoniae liver abscess has emerged in non-diabetic patients in Taiwan. Diabetic patients were at higher risk of acquiring gas-forming abscesses. Non diabetic patients and diabetic patients with optimal glycemic levels are more susceptible to the virulent capsular types of K. pneumoniae.

Pyogenic Liver Abscess: A Retrospective Study of 105 Cases in an Emergency Department from East China

BACKGROUND

Pyogenic liver abscesses have become common in emergency departments (EDs) in recent years in Shanghai, China due to a variety of risk factors contributory to the disease.

OBJECTIVE

To review our experience in managing pyogenic liver abscesses to aid in the current management of this complex condition.

METHODS

This retrospective study was conducted to collect and analyze information from adult patients diagnosed with liver hepatic abscesses who were admitted to Ren Ji Hospital during the period from January 1, 2010 to December 31, 2015. The demographic data, etiology, underlying diseases, clinical presentation, imaging features, laboratory examinations, microbiological tests, treatment, and clinical outcomes were analyzed.

RESULTS

The data of a total 105 patients were retrospectively analyzed. The mean age of the patients was 62.0 ± 13.5 years. The etiology was predominantly hepatobiliary disease (43/105, 40.1%) or diabetes mellitus (42/105, 40.0%). During hospitalization, 12 patients (11.4%) with septic shock required intensive care. One patient died, yielding a 0.9% fatality rate. In addition to empiric antimicrobial therapy, 66/105 (62.9%) patients underwent ultrasound-guided percutaneous drainage of the liver abscess at diagnosis. Only 3 patients required surgical intervention. Bacterial culture of pyogenic fluids revealed 25 positive results of 66 cases (37.9%). Among them, Klebsiella pneumoniae was the primary pathogen detected in 15 cases (60.0%).

CONCLUSIONS

Pyogenic liver abscesses have become common in EDs in Shanghai, China. The early recognition of the disease, prompt use of empirical antimicrobial therapy, initiation of drainage in the appropriate patients, and controlling the underlying conditions were crucial for preventing severe sepsis and improving the outcome.

Proton pump inhibitor use significantly increases the risk of cryptogenic liver abscess: a population-based study

BACKGROUND

Proton pump inhibitors (PPIs) increase gastric pH and impair defence mechanisms against ingested pathogens, which may result in the overgrowth of virulent Klebsiella pneumoniae in the intestine and subsequent liver abscess.

AIM

We investigated the possible association between PPIs use and cryptogenic liver abscess in Taiwan.

METHODS

We conducted a population-based case-control study using data from the National Health Insurance Research Database. A total of 958 adult cases of liver abscess and 3832 age- and sex-matched control patients were enrolled during 2000-2010. Conditional logistic regression was used to estimate the adjusted odds ratios (ORs) in patients using PPIs before cryptogenic liver abscess.

RESULTS

The adjusted OR associating current use of PPIs (prescription within the past 30 days) with cryptogenic liver abscess was 4.7 [95% confidence interval (CI), 2.9-7.8], and recent use of PPIs (prescription within the past 31-90 days) with cryptogenic liver abscess was 2.9 (95% CI, 1.4-6.1). A dose-response relationship was apparent for cumulative dose of PPIs within 90 days. Adjusted OR was highest among the patients receiving PPIs more than 60 cumulative defined daily dose (OR = 6.5, 95% CI, 2.8-14.9).

CONCLUSION

Proton pump inhibitor therapy within the past 90 days was associated with an increased risk of cryptogenic liver abscess.

TREM-1 promotes survival during Klebsiella pneumoniae liver abscess in mice

Klebsiella pneumoniae liver abscess (KPLA) is prevalent in East Asia. Liver abscess can develop after translocation of K. pneumoniae from a patient's bowel into the liver via the portal circulation. TREM-1 (triggering receptor expressed on myeloid cells 1) amplifies inflammatory signaling during infection, but its role in KPLA is poorly understood. We used an animal study to characterize the role of TREM-1 in KPLA. We compared survival rates, bacterial burdens in tissues, inflammatory cytokine levels, and histology findings between wild-type and Trem-1 knockout (KO) mice after oral inoculation of capsular type K1 K. pneumoniae. Translocation of K. pneumoniae to mesenteric lymph nodes and liver was examined, and intestinal permeability, antimicrobial peptide expression, and the clearance of K. pneumoniae in the small intestine were determined. In the absence of TREM-1, KPLA model mice showed increased K. pneumoniae dissemination, enhanced liver and systemic inflammation, and reduced survival. Impaired bacterial clearance in the small intestine causes enhanced K. pneumoniae translocation, which renders Trem-1 KO mice more susceptible to K. pneumoniae oral infection. In conclusion, TREM-1-mediated bacterial clearance in the small intestine is an important immune response against K. pneumoniae. TREM-1 deficiency enhances K. pneumoniae translocation in the small intestine and increases mortality rates in mice with KPLA.

Liver abscess due to Klebsiella pneumoniae: risk factors for metastatic infection

INTRODUCTION

Klebsiella pneumoniae-associated liver abscess (KPLA) is often accompanied by extrahepatic complications. We investigated the clinical features and outcomes of patients with and without metastatic infections and compared the 2 groups.

METHODS

We retrospectively reviewed the medical records of 161 patients with KPLA who were admitted to 2 tertiary referral hospitals in Korea.

RESULTS

In total, 9.9% had a metastatic infection. The most commonly involved distant sites were the eyes (n = 7) and the lungs (n = 6). In multivariate analysis, diabetes mellitus as an underlying disease (odds ratio (OR) 2.30, 95% confidence interval (CI) 1.05-9.51; p = 0.03) and a platelet count < 80,000/mm(3) (OR 11.60, 95% CI 2.53-53.26; p = 0.002) were associated with metastatic infection. Extended-spectrum beta-lactamase (ESBL) production was not observed in K. pneumoniae from patients with metastatic infection, whereas 3.4% of the bacteria in patients without metastatic infection had ESBL production. However, this difference was not statistically significant (p = 0.45). The in-hospital mortality rate was not significantly different (0% vs. 2.8%; p = 0.52). By multivariate analysis, the Acute Physiology and Chronic Health Evaluation II (APACHE II) score was independently associated with mortality among patients with KPLA (OR 1.5, 95% CI 1.12-2.00; p = 0.006).

CONCLUSIONS

Clinicians must be aware of potential metastatic infections in patients with KPLA, especially if they have diabetes mellitus and thrombocytopenia. The APACHE II score was predictive of mortality in patients with KPLA.

Clinical characteristics and economic consequence of Klebsiella pneumoniae liver abscess in Taiwan

BACKGROUND

Klebsiella pneumoniae liver abscess (KPLA) has emerged as an endemic disease in Taiwan, and its prevalence has been increasing in east Asian countries in the past three decades. The utilization of healthcare resources associated with KPLA is assumed to be substantial, and may be of future concern. This study investigated the clinical characteristics and economic burden of KPLA in Taiwan in 2011 and 2012.

METHODS

Adult patients with KPLA were identified retrospectively in a tertiary medical center in Taiwan from January 2011 to December 2012. The clinical characteristics, total and daily hospitalization expenditure, and the risk factors for the costs of KPLA were analyzed.

RESULTS

Among patients with KPLA, the median cost was $5290.80 in US dollars, and the mean cost was $6337.50 ± $4363.40. Length of hospital stay was the only independent risk factor for the high total hospitalization expenditure. The duration of antibiotic use was nearly the same as the length of hospital stay. The prolonged stay in the general ward (≥21 days) also contributed to the high total cost of hospitalization. The independent risk factors for the high average daily cost of hospitalization were a higher Charlson Comorbidity Index and the requirement of intensive care on admission.

CONCLUSION

The current study is the first to demonstrate the high economic burden resulting from KPLA in a medical center in Taiwan. Standardizing the treatment protocol for KPLA inpatients and introducing an outpatient parenteral antimicrobial therapy center to reduce the length of stay may reduce costs, whereas development of a vaccine may be necessary to tackle endemic KPLA in the future.

Ampicillin and amoxicillin use and the risk of Klebsiella pneumoniae liver abscess in Taiwan

BACKGROUND

Klebsiella pneumoniae liver abscess (KPLA) is prevalent in East Asia. Use of amoxicillin/ampicillin may lead to overgrowth of K. pneumoniae in the intestine and predispose to KPLA. We used an animal study and nationwide population-based database to investigate the association between ampicillin/amoxicillin use and KPLA in Taiwan.

METHODS

In an animal study, ampicillin or sterile water was administered orogastrically in serotype K1 K. pneumoniae-colonized mice and the outcome was compared. We identified 855 cases with liver abscess and selected 3420 age- and sex-matched control subjects from the National Health Insurance Research Database. Conditional logistic regression was used to estimate the adjusted odds ratios (ORs) for the association between recent use of ampicillin/amoxicillin and KPLA.

RESULTS

Ampicillin administration predisposed K. pneumoniae-colonized mice to increased bacterial burden, liver abscess and necrosis, and lethality. The population-based study showed that the adjusted OR associating the use of ampicillin/amoxicillin within the past 30 days with KPLA was 3.5 (95% confidence interval, 2.5-5.1). No association was found with use in the past 31-90 days.

CONCLUSIONS

Ampicillin/amoxicillin therapy started within the past 30 days was associated with increased risk for KPLA. We should avoid the overuse of these antibiotics to prevent undesired disease in the endemic area.

Klebsiella pneumoniae liver abscess in diabetic patients: association of glycemic control with the clinical characteristics

Background

Klebsiella pneumoniae liver abscess (KPLA) has been reported with increasing frequency in East Asian countries in the past 3 decades, especially in Taiwan and Korea. Diabetes is a well-known risk factor for KPLA and highly associated with septic metastatic complications from KPLA. We investigated the association of glycemic control in diabetic patients with the clinical characteristics of KPLA in Taiwan.

Methods

Adult diabetic patients with KPLA were identified retrospectively in a medical center from January 2007 to January 2012. Clinical characteristics were compared among patients with different levels of current hemoglobin A1c (HbA_1c). Risk factors for metastatic infection from KPLA were analyzed.

Results

Patients with uncontrolled glycemia (HbA_1c ≥ 7%) were significantly younger than those with controlled glycemia (HbA_1c < 7%). Patients with uncontrolled glycemia had the trend to have a higher rate of gas-forming liver abscess, cryptogenic liver abscess, and metastatic infection than those with controlled glycemia. Cryptogenic liver abscess and metastatic infection were more common in the poor glycemic control group (HbA_1c value >; 10%) after adjustment with age. HbA_1c level and abscess < 5 cm were independent risk factors for metastatic complications from KPLA.

Conclusions

Glycemic control in diabetic patients played an essential role in the clinical characteristics of KPLA, especially in metastatic complications from KPLA.

Hypervirulent (hypermucoviscous) Klebsiella pneumoniae: a new and dangerous breed

A new hypervirulent (hypermucoviscous) variant of Klebsiella pneumoniae has emerged. First described in the Asian Pacific Rim, it now increasingly recognized in Western countries. Defining clinical features are the ability to cause serious, life-threatening community-acquired infection in younger healthy hosts, including liver abscess, pneumonia, meningitis and endophthalmitis and the ability to metastatically spread, an unusual feature for enteric Gram-negative bacilli in the non-immunocompromised. Despite infecting a healthier population, significant morbidity and mortality occurs. Although epidemiologic features are still being defined, colonization, particularly intestinal colonization, appears to be a critical step leading to infection. However the route of entry remains unclear. The majority of cases described to date are in Asians, raising the issue of a genetic predisposition vs. geospecific strain acquisition. The traits that enhance its virulence when compared with “classical” K. pneumoniae are the ability to more efficiently acquire iron and perhaps an increase in capsule production, which confers the hypermucoviscous phenotype. An objective diagnostic test suitable for routine use in the clinical microbiology laboratory is needed. If/when these strains become increasingly resistant to antimicrobials, we will be faced with a frightening clinical scenario.