Pyogenic liver abscess as endemic disease, Taiwan

Klebsiella pneumoniae Liver Abscess and Metastatic Endophthalmitis

Introduction. Klebsiella pneumoniae is a well-known cause of liver abscess. Higher rates of liver abscess associated with Klebsiella pneumoniae are seen in Taiwan. Metastatic endophthalmitis is a common complication associated with a poor prognosis despite aggressive therapy. Case Report. We report a case of a 67-year-old Korean female with Klebsiella pneumoniae liver abscess. The patient developed metastatic endophthalmitis and ultimately succumbed to her disease despite aggressive medical and surgical treatment. Conclusion. Dissemination of Klebsiella pneumoniae is associated with significant morbidity and mortality. Liver abscesses preferably should be treated with percutaneous drainage, but surgical treatment is needed in some cases. Metastatic spread to the eye is a common complication that must be treated aggressively with intravenous antibiotics and surgical intervention if necessary.

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.

Genetic analysis of capsular polysaccharide synthesis gene clusters in 79 capsular types of Klebsiella spp

A total of 79 capsular types have been reported in Klebsiella spp., whereas capsular polysaccharide synthesis (cps) regions were available in only 22 types. Due to the limitations of serotyping, complete repertoire of cps will be helpful for capsular genotyping. We therefore resolved the rest 57 cps and conducted comparative analysis. Clustering results of 1,515 predicted proteins from cps loci categorized proteins which share similarity into homology groups (HGs) revealing that 77 Wzy polymerases were classified into 56 HGs, which indicate the high specificity of wzy between different types. Accordingly, wzy-based capsular genotyping could differentiate capsule types except for those lacking wzy (K29 and K50), those sharing identical wzy (K22 vs. K37); and should be carefully applied in those exhibited high similarity (K12 vs. K41, K2 vs. K13, K74 vs. K80, K79 vs. KN1 and K30 vs. K69). Comparison of CPS structures in several capsular types that shared similarity in their gene contents implies possible functions of glycosyltransferases. Therefore, our results provide complete set of cps in various types of Klebsiella spp., which enable the understandings of relationship between genes and CPS structures and are useful for identification of documented or new capsular types.

Splenectomy Correlates With Increased Risk of Pyogenic Liver Abscess: A Nationwide Cohort Study in Taiwan

OBJECTIVES

Little is known about the risk of pyogenic liver abscess in patients with splenectomy. We explored the relationship between splenectomy and pyogenic liver abscess in Taiwan.

METHODS

We conducted a nationwide cohort analysis using the hospitalization dataset of the Taiwan National Health Insurance Program. We included 17,779 subjects aged 20-84 years who underwent splenectomy in 1998 to 2010 (splenectomy group) and 70,855 randomly selected subjects without splenectomy (non-splenectomy group). Both groups were matched by sex, age, other comorbidities, and hospitalization year of receiving splenectomy. The incidence of pyogenic liver abscess at the end of 2011 was measured. The multivariable Cox proportional hazard regression model was used to estimate the hazard ratios and 95% confidence intervals for pyogenic liver abscess associated with splenectomy and other comorbidities.

RESULTS

The overall incidence rate was 3.75-fold higher in the splenectomy group than that in the non-splenectomy group (2.15 vs 0.57 per 1000 person-years; 95% confidence interval, 3.57-3.94). After controlling for potential confounding factors, the adjusted hazard ratio of pyogenic liver abscess was 3.89 in subjects with splenectomy (95% confidence interval, 3.20-4.72) when compared with subjects without splenectomy. In further analysis, the hazard ratio markedly increased to 14.34 for those with splenectomy and having any of the assessed comorbidities, including alcoholism, biliary stone, chronic kidney disease, chronic liver diseases, and diabetes mellitus (95% confidence interval, 10.61-19.39).

CONCLUSIONS

Patients with splenectomy are at an increased risk of developing pyogenic liver abscess, particularly when they have comorbid conditions.

Zolpidem Use Associated With Increased Risk of Pyogenic Liver Abscess: A Case-Control Study in Taiwan

The purpose of this study was to explore the association between zolpidem use and pyogenic liver abscess in Taiwan.This was a population-based case-control study using the database of the Taiwan National Health Insurance Program since 2000 to 2011. We identified 1325 patients aged 20 to 84 years with the first-attack of pyogenic liver abscess as the cases, and 5082 patients without pyogenic liver abscess matched with sex, age, comorbidities, and index year of hospitalization for pyogenic liver abscess as the controls. Patients whose last remaining 1 tablet for zolpidem was noted ≤7 days before the date of admission for pyogenic liver abscess were defined as current use of zolpidem. Patients whose last remaining 1 tablet for zolpidem was noted >7 days before the date of admission for pyogenic liver abscess were defined as late use of zolpidem. Patients who never received 1 prescription for zolpidem were defined as never use of zolpidem. A multivariable unconditional logistic regression model was used to measure the odds ratio (OR) and 95% confidence interval (CI) to explore the association between zolpidem use and pyogenic liver abscess.After adjustment for possible confounding variables, the adjusted OR of pyogenic liver abscess was 3.89 for patients with current use of zolpidem (95% CI 2.89, 5.23), when compared with those with never use of zolpidem. The adjusted OR decreased to 0.85 for those with late use of zolpidem (95% CI 0.70, 1.03), but without statistical significance.Current use of zolpidem is associated with the increased risk of pyogenic liver abscess. Physicians should take the risk of pyogenic liver abscess into account when prescribing zolpidem.

Mapping the Evolution of Hypervirulent Klebsiella pneumoniae

Highly invasive, community-acquired Klebsiella pneumoniae infections have recently emerged, resulting in pyogenic liver abscesses. These infections are caused by hypervirulent K. pneumoniae (hvKP) isolates primarily of capsule serotype K1 or K2. Hypervirulent K1 isolates belong to clonal complex 23 (CC23), indicating that this clonal lineage has a specific genetic background conferring hypervirulence. Here, we apply whole-genome sequencing to a collection of K. pneumoniae isolates to characterize the phylogenetic background of hvKP isolates with an emphasis on CC23. Most of the hvKP isolates belonged to CC23 and grouped into a distinct monophyletic clade, revealing that CC23 is a unique clonal lineage, clearly distinct from nonhypervirulent strains. Separate phylogenetic analyses of the CC23 isolates indicated that the CC23 lineage evolved recently by clonal expansion from a single common ancestor. Limited grouping according to geographical origin was observed, suggesting that CC23 has spread globally through multiple international transmissions. Conversely, hypervirulent K2 strains clustered in genetically unrelated groups. Strikingly, homologues of a large virulence plasmid were detected in all hvKP clonal lineages, indicating a key role in K. pneumoniae hypervirulence. The plasmid encodes two siderophores, aerobactin and salmochelin, and RmpA (regulator of the mucoid phenotype); all these factors were found to be restricted to hvKP isolates. Genomic comparisons revealed additional factors specifically associated with CC23. These included a distinct variant of a genomic island encoding yersiniabactin, colibactin, and microcin E492. Furthermore, additional novel genomic regions unique to CC23 were revealed which may also be involved in the increased virulence of this important clonal lineage.

IMPORTANCE

During the last 3 decades, hypervirulent Klebsiella pneumoniae (hvKP) isolates have emerged, causing severe community-acquired infections primarily in the form of pyogenic liver abscesses. This syndrome has so far primarily been found in Southeast Asia, but increasing numbers of cases are being reported worldwide, indicating that the syndrome is turning into a globally emerging disease. We applied whole-genome sequencing to a collection of K. pneumoniae clinical isolates to reveal the phylogenetic background of hvKP and to identify genetic factors associated with the increased virulence. The hvKP isolates primarily belonged to clonal complex 23 (CC23), and this clonal lineage was revealed to be clearly distinct from nonhypervirulent strains. A specific virulence plasmid was found to be associated with hypervirulence, and novel genetic determinants uniquely associated with CC23 were identified. Our findings extend the understanding of the genetic background of the emergence of hvKP clones.

Endogenous endophthalmitis complicated by pyogenic liver abscess: a review of 17 years' experience at a single center

BACKGROUND

Endogenous endophthalmitis is a rare complication of pyogenic liver abscess. It is a devastating intraocular infection which constitutes a vision-threatening emergency. Recently, a significant increase in the incidence of endogenous endophthalmitis associated with pyogenic liver abscess has been reported in East Asia. In this study, the authors investigated the incidence, risk factors, clinical features, and treatment outcomes of endogenous endophthalmitis arising as a complication of pyogenic liver abscess.

METHODS

The medical records of 8 cases of endogenous endophthalmitis associated with a pyogenic liver abscess treated from 1997 to 2013 at a single tertiary hospital in Korea were retrospectively reviewed.

RESULTS

Median patient age was 71.1 ± 9.8 years. The most common underlying disease was diabetes mellitus (4 patients, 50%). Klebsiella pneumoniae was isolated from all patients, and all were treated with intravenous antibiotics including ceftriaxone. Seven patients received an intravitreal injection. Four patients needed additional surgical interventions. Outcomes were generally poor; only 1 patient achieved a slight improvement in visual outcome.

CONCLUSION

Old age, diabetes mellitus, and K. pneumoniae infection could predispose the development of endogenous endophthalmitis in patients with a pyogenic liver abscess. Physicians should pay attention to ocular symptoms as early diagnosis and intensive treatment are required to achieve improvements in visual 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.

Transfer of CMY-2 Cephalosporinase from Escherichia coli to Virulent Klebsiella pneumoniae Causing a Recurrent Liver Abscess

A CMY-2-producing capsular type K2 Klebsiella pneumoniae strain (TVGHKP93) with multidrug resistance was isolated from a recurrent liver abscess in a patient who also carried a CMY-2-producing Escherichia coli strain (TVGHEC01) in the stool. TVGHKP93 retained its high virulence compared with that of the isogenic strain (TVGHKP60) with wild-type resistance from the first liver abscess. Our conjugation experiment showed the successful transfer of the blaCMY-2-carrying plasmid from TVGHEC01 into TVGHKP60. The transconjugant showed both high virulence and the multidrug-resistant phenotype, as did TVGHKP93.

Association between periodontal disease and septicemia due to pyogenic hepatic abscess

Case of a 65 year-old man with type-2 diabetes mellitus for<br />15 years who complained of abdominal pain in the right upper<br />quadrant associated with unquantified fever and weight loss<br />over a period of 25 days. In the emergency room, he presented<br />tachycardia, tachypnea and fever of 37 º C, diffuse abdominal<br />pain from light palpation without peritoneal irritation or<br />right upper quadrant tenderness upon fist percussion test.<br />Within a few hours the patient evolved to septic shock and<br />required transfer to the intermediate care unit. The abdominal<br />computerized axial tomography showed multiloculated<br />hepatic abscess. Percutaneous drainage was performed with<br />the culture positive for Escherichia coli and Fusobacterium<br />spp. Then, the differential diagnosis was made between<br />pyogenic or amebic liver abscess. Subsequently, oral cavity<br />examination revealed severe periodontal disease with coronal<br />destruction; therefore, extraction was scheduled.

Multi-organ failure secondary to a Clostridium perfringens gaseous liver abscess following a self-limited episode of acute gastroenteritis

BACKGROUND

Clostridium perfringens is an unusual pathogen responsible for the development of a gas-forming pyogenic liver abscess. Progression to septicemia with this infection has amplified case fatality rates.

CASE REPORT

We report a case of an 81-year-old lady with pyogenic liver abscess with gas formation that was preceded by an acute gastroenteritis. The most common precipitating factors are invasive procedures and immunosuppression. Clostridium perfringens was unexpectedly isolated in the drained abscess, as well as blood. It is a normal inhabitant of the human bowel and a common cause of food poisoning, notoriously leading to tissue necrosis and gas gangrene.

CONCLUSIONS

We report a case of gas-forming pyogenic liver abscess and bacteremia progressing to fatal septic shock, caused by an uncommon Clostridium perfringens isolate.

Pyogenic liver abscess correlates with increased risk of acute pancreatitis: a population-based cohort study

BACKGROUND

The aim of this study was to explore whether there is a relationship between pyogenic liver abscess (PLA) and subsequent risk of acute pancreatitis in Taiwan.

METHODS

Using inpatients claims data from the Taiwan National Health Insurance Program, we identified 30 866 subjects aged 20-84 years with the first-attack of PLA from 2000 to 2010 as the PLA group and randomly selected 123 464 subjects without PLA as the non-PLA group. The incidence of the first attack of acute pancreatitis at the end of 2010 and the risk associated with PLA and other comorbidities were measured.

RESULTS

The overall incidence of acute pancreatitis was 3.84-fold greater in the PLA group than in the non-PLA group (4.61 vs 1.19 events per 1000 person-years; 95% CI, 3.43-4.29). After controlling for potential confounding factors, the adjusted hazard ratio of acute pancreatitis was 3.00 (95% CI, 2.62-3.43) for the PLA group, as compared to the non-PLA group. Further analysis showed that compared to subjects with neither PLA nor comorbidities, patients with PLA and hypertriglyceridemia, biliary stones, alcoholism, or hepatitis C had greater risk of acute pancreatitis than those with PLA alone.

CONCLUSIONS

PLA correlates with increased risk of subsequent acute pancreatitis. Comorbidities, including hypertriglyceridemia, biliary stones, alcoholism, and hepatitis C, may enhance the risk of developing acute pancreatitis.

Risk factors and clinical outcomes for spontaneous rupture of pyogenic liver abscess

OBJECTIVE

To evaluate the risk factors and clinical outcomes in patients with spontaneous rupture of pyogenic liver abscess (PLA).

METHODS

A total of 602 patients diagnosed with PLA between January 2004 and July 2013 were retrospectively analyzed. Among them, 23 patients experienced a spontaneous rupture of liver abscess (SRLA).

RESULTS

The prevalence of SRLA was 3.8%. Using multivariate analysis, liver cirrhosis (OR 4.651, P = 0.009), gas-forming abscesses (OR 3.649, P = 0.026), abscess ≥6 cm in diameter (OR 10.989, P = 0.002) and other septic metastases (OR 1.710, P = 0.047) were risk factors for SRLA. Regarding the site of rupture, 20 (87.0%) patients had a localized rupture, specifically, subphrenic abscess in 3 (13.0%), peri-hepatic abscess in 10 (43.5%), localized peritoneal abscess in 3 (13.0%) and empyema in 4 (17.5%); and the other 3 (13%) had peritonitis. Ruptures resulting in peritonitis require urgent surgery, whereas localized ruptures were managed with surgical or percutaneous drainage in addition to appropriate antibiotics. The in-hospital mortality rate of SRLA was 4.3%.

CONCLUSION

Patients with cirrhosis, having abscess ≥6 cm in diameter, gas-forming abscesses and other septic metastases in those with PLA should be monitored closely and may need early intervention for SRLA.

Identification of an immuno-dominant protein from Klebsiella pneumoniae strains causing pyogenic liver abscess: implication in serodiagnosis

Background

Klebsiella pneumoniae has emerged worldwide as a cause of pyogenic liver abscess (PLA) often complicated by meningitis and endophthalmitis. Early detection of this infectious disease will improve its clinical outcome. Therefore, we tried to isolate immunodominant proteins secreted by K. pneumoniae strains causing PLA.

Results

The secreted proteins of the NTUH-K2044 strain were separated by two-dimensional electrophoresis and then immunoblotted using convalescent sera from patients with K. pneumoniae PLA. A ~30-kDa immunodominant protein was then identified. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) revealed an open reading frame (KP1_p307) located on the pK2044 plasmid and bioinformatic analysis identified this protein as a signal peptide of unknown function. The KP1_p307 gene was more prevalent in PLA strains and capsular type K1/K2 strains, but disruption of this gene in NTUH-K2044 strain did not decrease virulence in mice. Ten of fourteen (71%) sera from patients with K. pneumoniae PLA were immunoreactive with the recombinant KP1_p307 protein. Seroconversion demonstrated by a rise in serum titer in serial serum samples confirmed that antibodies against the KP1_p307 protein were elicited after infection.

Conclusions

The KP1_p307 protein could be used as an antigen for early serodiagnosis of K. pneumoniae PLA, particularly in K1/K2 PLA strains.

Identification of capsular types in carbapenem-resistant Klebsiella pneumoniae strains by wzc sequencing and implications for capsule depolymerase treatment

Klebsiella pneumoniae is an important human pathogen associated with a variety of diseases, and the prevalence of multidrug-resistant K. pneumoniae (MDRKP) is rapidly increasing. Here we determined the capsular types of 85 carbapenem-resistant K. pneumoniae (CRKP) strains by wzc sequencing and investigated the presence of carbapenemases and integrons among CRKP strains. Ten CRKP strains (12%) were positive for carbapenemase (imipenemase, 6/85 strains; K. pneumoniae carbapenemase, 3/85 strains; Verona integron-encoded metallo-β-lactamase, 1/85 strains). Capsular type K64 accounted for 32 CRKP strains (38%), followed by K62 (13%), K24 (8%), KN2 (7%), and K28 (6%). Sequence types (STs) were determined by multilocus sequence typing (MLST), and the results indicated that ST11, which accounted for 47% of these CRKP strains (40/85 strains), was the major ST. We further isolated a K64-specific capsule depolymerase (K64dep), which could enhance serum and neutrophil killing in vitro and increase survival rates for K64 K. pneumoniae-inoculated mice. The toxicity study demonstrated that mice treated with K64dep showed normal biochemical parameters and no significant histopathological changes of liver, kidney, and spleen, indicating that enzyme treatment did not cause toxicity in mice. Therefore, the findings of capsular type clustering among CRKP strains and effective treatment with capsule depolymerase for MDRKP infections are important for capsule-based vaccine development and therapy.

Epidemiology and clinical outcome of pyogenic liver abscess: an analysis from the National Health Insurance Research Database of Taiwan, 2000-2011

BACKGROUND

The epidemiology of pyogenic liver abscess continues to change and the issue of antimicrobial therapy is controversial. This study investigated the epidemiology and clinical outcomes of antimicrobial therapy.

METHODS

The annual incidence rates, demographic data, underlying diseases, complications, length of stay, mortality rates, and antimicrobial therapy were analyzed using the data retrieved from the Longitudinal Health Insurance Database 2000, Taiwan, from 2000 to 2011.

RESULTS

The annual incidence of pyogenic liver abscess for all age groups increased gradually in Taiwan from 10.83 per 100,000 person-years in 2000 to 15.45 per 100,000 person-years in 2011. Pyogenic liver abscess occurred more commonly in patients with male sex, of older age (>50 years), and lower family income. Among the 1522 adult patients with pyogenic liver abscess, 537 (35.3%) patients had diabetes mellitus, 165 (10.8%) patients had complications, 234 (15.4%) patients received mechanical ventilation, and 361 (23.7%) patients had a stay in intensive care; the mortality rate was 8.2% (125/1522). There were 426 (28%) patients treated with cefazolin and 158 (10.4%) patients treated with extended-spectrum cephalosporins. There were no statistically significant differences in the length of stay and mortality rates between these two groups (20.2 days vs. 23.1 days; and 7.5% vs. 10.1%, respectively).

CONCLUSION

The clinical outcomes of pyogenic liver abscess treated with cefazolin were comparable to those treated by extended-spectrum cephalosporins. Extended-spectrum cephalosporins should be used for severe complications, such as meningitis and endophthalmitis. Further surveillance of epidemiology and cohort analysis of antimicrobial therapy are important.

D-galactan II is an immunodominant antigen in O1 lipopolysaccharide and affects virulence in Klebsiella pneumoniae: implication in vaccine design

In the O1 strain of Klebsiella, the lipopolysaccharide (LPS) O-antigen is composed of D-galactan I and D-galactan II. Although the composition of the O1 antigen of Klebsiella was resolved more than two decades, the genetic locus involved in the biosynthesis of D-galactan II and the role of D-galactan II in bacterial pathogenesis remain unclear. Here, we report the identification of the D-galactan II-synthesizing genes by screening a transposon mutant library of an acapsulated Klebsiella pneumoniae O1 strain with bacteriophage. K. pneumoniae strain deleted for wbbY exhibited abrogated D-galactan II production; altered serum resistance and attenuation of virulence. Serologic analysis of K. pneumoniae clinical isolates demonstrated that D-galactan II was more prevalent in community-acquired pyogenic liver abscess (PLA)—causing strains than in non-tissue-invasive strains. WbbY homologs, WbbZ homologs, and lipopolysaccharide structures based on D-galactan II also were present in several Gram-negative bacteria. Immunization of mice with the magA-mutant (K⁻₁ O₁) (that is, with a LPS D-galactan II-producing strain) provided protection against infection with an O1:K2 PLA strain. Our findings indicate that both WbbY and WbbZ homologs are sufficient for the synthesis of D-galactan II. D-galactan II represents an immunodominant antigen; is conserved among multiple species of Gram-negative bacteria and could be a useful vaccine candidate.

Predictors of therapy failure in a series of 741 adult pyogenic liver abscesses

BACKGROUND

Adult pyogenic liver abscess (PLA) is a major hepato-biliary infection. We aim to identify risk factors associated with therapy failure.

METHODS

Retrospective study of 741 PLA patients (2001-2011) and comparison with earlier data (1994-1997). Risk factors associated with therapy failure were identified with multivariate analysis.

RESULTS

Incidence of PLA is 86/100 000 admissions, with average size 5.75 cm. 68% of PLA were secondary to Klebsiella pneumoniae and there is increasing extended-spectrum beta-lactamase (ESBL) resistance. Compared with 1990s, there is an increasing annual incidence (from 18 to 67). Elderly age (≥55-years-old), presence of multiple abscesses, malignancy as etiology and patients who underwent endoscopic intervention are independent predictors for failure of antibiotics-only therapy while average intravenous antibiotics duration and average abscess size are not. ECOG performance status ≥2, pre-existing hypertension and hyperbilirubinaemia are independent predictors for failure of percutaneous therapy while the presence of multiple abscesses and average abscess size are not.

CONCLUSION

There is an increasing PLA incidence with increasing ESBL resistance. Percutaneous drainage should be considered early for elderly patients (≥55-years-old), with multiple abscesses, malignancy as etiology or who required endoscopic intervention. We should have a low threshold for surgical intervention for patients with ECOG performance status ≥2, co-morbidity of hypertension or hyperbilirubinaemia.

The incidence, risk factors, and outcomes of acute kidney injury in patients with pyogenic liver abscesses

BACKGROUND

Acute kidney injury (AKI) can occur in various infectious conditions. Liver abscess is relatively rare, but can lead to sepsis and/or other severe complications. Few studies of AKI in patients with a liver abscess have been conducted. Therefore, we analyzed the clinical and laboratory data of AKI in patients with a liver abscess.

METHODS

We retrospectively reviewed the medical records of patients who were diagnosed with a liver abscess from January 2000 to March 2013. The study included 404 patients with a liver abscess confirmed by clinical presentation and computed tomography.

RESULTS

AKI occurred in 137 patients (34 %). As per RIFLE classification, renal injury was graded as either at risk of renal dysfunction (35.8 %), renal injury (47.4 %), and renal failure (16.5 %). AKI occurred more frequently in males and patients with liver cirrhosis (P < 0.001 and P = 0.005). Patients with AKI had lower serum albumin and higher AST and ALT levels than did patients without AKI. Bacteria were frequently isolated in AKI patients from blood culture and liver abscess aspirates (P < 0.001 and P = 0.007). The occurrence of septic shock was positively correlated with AKI (P = 0.002) and AKI was more frequent in patients with chronic kidney disease (P = 0.04). Higher mortality was observed in CKD patients accompanied by AKI (P < 0.001). Three patients with AKI underwent hemodialysis; two patients who had initially normal renal function completely recovered whereas one CKD patient progressed to ESRD, requiring maintenance hemodialysis.

CONCLUSION

AKI is relatively common in patients with liver abscess. Physicians should therefore attempt to prevent, detect, and manage AKI early in patients with liver abscess.

Initial presentations and final outcomes of primary pyogenic liver abscess: a cross-sectional study

Background

Although pyogenic liver abscess (PPLA) fatalities are decreasing owing to early diagnosis and effective treatments, PPLA-associated complications still exist. The purpose of this study was to analyze the characteristic features of initial presentations and final outcomes of PPLA caused by different pathogens.

Methods

This retrospective study collected and analyzed information regarding initial presentations and final outcomes in patients diagnosed with PPLA at admitted at Changhua Christian Hospital from January 1 to December 31, 2010.

Results

During the study period, we analyzed the records of a total of 134 patients with documented PPLA. There were no significant causative pathogen-related differences in symptoms at initial presentation. Compared with the survivor group, patients in the mortality group were characterized by male gender (p < 0.001), malignancy (p < 0.001), respiratory distress (p =0.007), low blood pressure (p = 0.024), jaundice (p = < 0.001), rupture of liver abscess (p < 0.001), endophthalmitis (p = 0.003), and multiple organ failure (p < 0.001). No patients received liver transplantation or were diagnosed with HIV during the study period. According to univariate logistic regression analysis, gender (OR = 1.185, 95% CI: 0.284–11.130, p = 0.006), malignancy (OR = 2.067, 95% CI: 1.174–13.130, p = 0.004), respiratory distress (OR = 1.667, 95% CI: 1.164–14.210, p = 0.006), low blood pressure (OR = 2.167, 95% CI: 2.104–13.150, p = 0.003), jaundice (OR = 1.9, 95% CI: 1.246–3.297, p = 0.008), rupture of liver abscess (OR = 5.167, 95% CI: 2.194–23.150, p = 0.003), endophthalmitis (OR = 2.167, 95% CI: 1.234–13.140, p = 0.005), and multiple organ failure (OR = 3.067, 95% CI: 1.184–15.150, p = 0.001) differed significantly between the mortality and survivor groups.

Conclusion

Although the initial presentations of PPLA caused by different pathogens were similar, there were significant differences in mortality in cases involving: (1) male patients, (2) malignancy, (3) initial respiratory distress, (4) initial low blood pressure, (5) jaundice, (6) rupture of liver abscess, (7) endophthalmitis, , and (8) multiple organ failure. We strongly recommend using a severity score of the disease to determine the risk of mortality for each patient with PPLA. In order to prevent complications and reduce mortality, more attention must be paid to high-risk PPLA patients.

First isolate of KPC-2-producing Klebsiella pneumonaie sequence type 23 from the Americas

KPC-2-producing Klebsiella pneumoniae isolates mainly correspond to clonal complex 258 (CC258); however, we describe KPC-2-producing K. pneumoniae isolates belonging to invasive sequence type 23 (ST23). KPC-2 has scarcely been reported to occur in ST23, and this report describes the first isolation of this pathogen in the Americas. Acquisition of resistant markers in virulent clones could mark an evolutionary step toward the establishment of these clones as major nosocomial pathogens.

Pyogenic liver abscess in end-stage renal disease patients: a nationwide longitudinal study

End-stage renal disease (ESRD) patients are more prone to infectious disease because of their immunocompromised status. However, the association between pyogenic liver abscess (PLA) and ESRD remains not clear. The aim of our study is to evaluate the incidence, risk factors, and outcomes of PLA in ESRD patients. We recruited all incident ESRD patients from the Taiwan National Health Insurance database from 1998 to 2006. The incidence rate of PLA in ESRD patients was compared with that of a randomly selected non-ESRD control group matched for age, sex gender, Charlson comorbidity score, diabetes mellitus, and cirrhosis. Among the 57,761 incident dialysis patients, there were 538 cases of PLA. The incidence rate of PLA was 18.20 per 10,000 person-years in the ESRD cohort and 6.34 per 10,000 person-years in matched control cohort. The rate of PLA was significantly higher in the ESRD cohort (hazard ratio 3.63, 95% confidence interval 2.83-4.65, P < 0.001). The mortality rates of PLA were higher in the ESRD cohort than those in matched control cohort. Diabetes mellitus was an independent risk factor for mortality of PLA. Compared with non-ESRD patients, ESRD patients have a higher risk of PLA and poorer outcomes.

Emerging K1 serotype Klebsiella pneumoniae primary liver abscess: three cases presenting to a single university hospital in Norway

Key Clinical Message

Community-acquired Klebsiella pneumoniae primary liver abscess (KLA) has been emerging worldwide over the past two decades and with high incidence in Asia. The presence of specific virulence characteristics is a risk factor for a syndrome with metastatic complications. This report signals an increasing emergence in Northern Europe.

Pyogenic liver abscess as a warning sign for primary liver cancer: a nationwide population-based study

BACKGROUND

There have been no large-scale population-based studies to estimate the subsequent risk of primary liver cancer (PLC) among patients with pyogenic liver abscess (PLA). This study aimed to provide relevant data.

MATERIALS AND METHODS

The Taiwan Longitudinal Health Insurance Database for the years 2000 and 2005 was used. The PLA group were adult inpatients who were newly diagnosed with PLA from 2000 to 2008. The control group was randomly selected and matched with the PLA group in terms of age, sex, and date in which medical treatment was sought other than for PLA.

RESULTS

There were 1,987 patients each in the PLA and control groups. In total, 56 had PLC, 48 (2.4%, 601.5 per 100,000 person-years) from the PLA group, and 8 from the control group. After adjusting for potential covariates, the hazard ratio of PLC for the PLA group was 3.4 times that of the control group (95% confidence interval = 1.6-7.3, p <0.001). The PLC risk for the PLA group was significantly higher within the first year after PLA diagnosis (hazard ratio: 35.4) as compared with the control group and became insignificant (hazard ratio: 2.0, 95% confidence interval = 0.8-4.9) more than one year after PLA diagnosis.

CONCLUSIONS

Patients with PLA have a higher rate of PLC than matched controls, especially within the first year after the diagnosis of PLA, suggesting PLA is a warning sign for PLC.

First Case of Liver Abscess in Scandinavia Due to the International Hypervirulent Klebsiella Pneumoniae Clone ST23

This is the first case report from Scandinavia of a pyogenic liver abscess caused by a Klebsiella pneumoniae isolate belonging to the international hyper virulent clone ST23. The patient, an 85-year old Caucasian, had no history of foreign travel or any classical predisposing factors for infection. The isolate was hypermucoviscous of capsular serotype K1 and carried the virulence factors aerobactin, allS, kfu and rmpA.

Epidemiology and mortality of liver abscess in end-stage renal disease dialysis patients: Taiwan national cohort study

BACKGROUND AND OBJECTIVES

To determine the incidence rates and mortality of liver abscess in ESRD patients on dialysis.

DESIGN SETTING PARTICIPANTS & MEASUREMENTS

Using Taiwan's National Health Insurance Research Database, we collected data from all ESRD patients who initiated dialysis between 2000 and 2006. Patients were followed until death, end of dialysis, or December 31, 2008. Predictors of liver abscess and mortality were identified using Cox models.

RESULTS

Of the 53,249 incident dialysis patients identified, 447 were diagnosed as having liver abscesses during the follow-up period (224/100,000 person-years). The cumulative incidence rate of liver abscess was 0.3%, 1.1%, and 1.5% at 1 year, 5 years, and 7 years, respectively. Elderly patients and patients on peritoneal dialysis had higher incidence rates. The baseline comorbidities of diabetes mellitus, polycystic kidney disease, malignancy, chronic liver disease, biliary tract disease, or alcoholism predicted development of liver abscess. Overall in-hospital mortality was 10.1%.

CONCLUSIONS

The incidence of liver abscess is high among ESRD dialysis patients. In addition to the well known risk factors of liver abscess, two other important risk factors, peritoneal dialysis and polycystic kidney disease, were found to predict liver abscess in ESRD dialysis patients.

Role of C-reactive protein in response-guided therapy of pyogenic liver abscess

BACKGROUND

Protocols for antibiotic treatment of pyogenic liver abscess (PLA) are usually based on clinicians' own experience without any validation. Our study was to evaluate the clinical implication of C-reactive protein (CRP) in predicting treatment outcome and adequacy of antibiotic therapy of PLA.

PATIENTS AND METHODS

Patients with PLA in whom white blood cell (WBC) count, erythrocyte sedimentation rate (ESR), and CRP were checked regularly during the clinical course were included. The prolife of CRP during the clinical course was compared with that of ESR and WBC. The usefulness of CRP in predicting the chance of recovery and adequacy of antibiotic therapy was examined.

RESULTS

From 2000 to 2011, 109 patients with PLA underwent regular monitoring of WBC, ESR, and CRP. Except for ESR, both WBC and CRP showed an initial rapid reduction in first 3 weeks, followed by a relatively slow decrease. From week 3 to week 6, the CRP ratio (relative to CRP at week 1) of patients with and without adverse events (i.e. including mortality) was compared; a significant difference was found at week 3 (P=0.001), week 4 (P=0.004), week 5 (P=0.011), and week 6 (P=0.018), whereas no statistically significant difference was found in the WBC ratio over the same period. By week 3, a CRP ratio of 0.423 or less was a marker of good outcome (sensitivity 0.846; specificity 0.667) and was also a marker of adequacy of antibiotic therapy of 5 weeks or less (sensitivity 0.786; specificity 0.714) if the ratio was 0.278 or less.

CONCLUSION

Weekly CRP measurement was useful in the identification of patients with PLA with good outcome and adequacy of antibiotic therapy of 5 weeks or less.

Capsule deletion via a λ-Red knockout system perturbs biofilm formation and fimbriae expression in Klebsiella pneumoniae MGH 78578

Background

Klebsiella pneumoniae is a leading cause of hospital-acquired urinary tract infections and pneumonia worldwide, and is responsible for many cases of pyogenic liver abscess among diabetic patients in Asia. A defining characteristic of this pathogen is the presence of a thick, exterior capsule that has been reported to play a role in biofilm formation and to protect the organism from threats such antibiotics and host immune challenge.

Findings

We constructed two knockout mutants of K. pneumoniae to investigate how perturbations to capsule biosynthesis alter the cellular phenotype. In the first mutant, we deleted the entire gene cluster responsible for biosynthesis of the extracellular polysaccharide capsule. In the second mutant, we deleted the capsule export subsystem within this cluster. We find that both knockout mutants have lower amounts of capsule but produce greater amounts of biofilm. Moreover, one of the two mutants abolishes fimbriae expression as well.

Conclusions

These results are expected to provide insight into the interaction between capsule biosynthesis, biofilm formation, and fimbriae expression in this organism.

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.

Characterization of Klebsiella sp. strain 10982, a colonizer of humans that contains novel antibiotic resistance alleles and exhibits genetic similarities to plant and clinical Klebsiella isolates

A unique Klebsiella species strain, 10982, was cultured from a perianal swab specimen obtained from a patient in the University of Maryland Medical Center intensive care unit. Klebsiella sp. 10982 possesses a large IncA/C multidrug resistance plasmid encoding a novel FOX AmpC β-lactamase designated FOX-10. A novel variant of the LEN β-lactamase was also identified. Genome sequencing and bioinformatic analysis demonstrated that this isolate contains genes associated with nitrogen fixation, allantoin metabolism, and citrate fermentation. These three gene regions are typically present in either Klebsiella pneumoniae clinical isolates or Klebsiella nitrogen-fixing endophytes but usually not in the same organism. Phylogenomic analysis of Klebsiella sp. 10982 and sequenced Klebsiella genomes demonstrated that Klebsiella sp. 10982 is present on a branch that is located intermediate between the genomes of nitrogen-fixing endophytes and K. pneumoniae clinical isolates. Metabolic features identified in the genome of Klebsiella sp. 10982 distinguish this isolate from other Klebsiella clinical isolates. These features include the nitrogen fixation (nif) gene cluster, which is typically present in endophytic Klebsiella isolates and is absent from Klebsiella clinical isolates. Additionally, the Klebsiella sp. 10982 genome contains genes associated with allantoin metabolism, which have been detected primarily in K. pneumoniae isolates from liver abscesses. Comparative genomic analysis of Klebsiella sp. 10982 demonstrated that this organism has acquired genes conferring new metabolic strategies and novel antibiotic resistance alleles, both of which may enhance its ability to colonize the human body.

Increased incidence of gastrointestinal cancers among patients with pyogenic liver abscess: a population-based cohort study

BACKGROUND & AIMS

The relationship between pyogenic liver abscess (PLA) and gastrointestinal (GI) cancer was first reported more than 20 years ago, yet little is known about this connection. We evaluated this association in a population-based, retrospective, cohort study.

METHODS

Using Taiwan National Health Insurance claims data, we collected data on a cohort of 14,690 patients with PLA diagnosed from 2000 to 2007. A reference cohort of 58,760 persons without PLA (controls) was selected from the same database, frequency matched by age, sex, and index year. Both cohorts were followed up until the end of 2009, and incidences of GI cancer were calculated.

RESULTS

The incidence of GI cancer was 4.30-fold higher among patients with PLA compared with controls (10.8 vs 2.51/1000 person-years). Site-specific analysis showed that the highest incidence of colorectal cancer was among patients with PLA and diabetes mellitus, followed by patients with PLA without diabetes and controls with diabetes (9.58, 5.76, and 1.49/10,000 person-years, respectively). The PLA cohort also had a high risk of small intestine cancer (adjusted hazard ratio [aHR], 12.7; 95% confidence interval [CI], 5.79-27.7) and biliary tract cancer (aHR, 9.56; 95% CI, 6.68-13.7). Their risk of pancreatic cancer (aHR, 2.51; 95% CI, 1.68-3.76) was also significant. However, patients with PLA did not have an increased risk of gastric cancer compared with controls.

CONCLUSIONS

In a population-based study, we found that the incidence of GI cancer is increased more than 4-fold among patients with PLA compared with controls. PLA might therefore be an indicator of GI cancer. Patients with PLA had the highest incidence of colorectal cancer, followed by cancers of the biliary tract, pancreas, and small intestine.

Pyogenic liver abscess and the emergence of Klebsiella as an etiology: a retrospective study

Objectives

Pyogenic liver abscess (PLA) is a significant, though uncommon, cause of morbidity in the United States. Recently, Klebsiella has emerged as an important cause of PLA. We analyzed the clinical course, microbiology, and treatment outcomes of patients discharged with PLA. In addition, we sought to examine the incidence of and risk factors for Klebsiella liver abscess (KLA).

Methods

We reviewed the charts of patients who discharged with PLA from two teaching hospitals in West Texas between January 1, 2007 and December 31, 2011.

Results

We identified 49 cases of PLA. Abscess cultures were positive in 23 (48%) patients. The mean age of the cohort was 56 years (range: 20–83 years). Sixty percent were male. The most frequent conditions associated with PLA were intra-abdominal infections (ten cases; 20%), diabetes mellitus (nine cases; 18%) and malignancy (nine cases; 18%). Klebsiella was the most commonly isolated species from the abscess cultures (seven cases; 30% of all positive abscess cultures). We used univariate and logistic regression analyses to identify the risk factors for KLA. Controlling for age, only malignancy was identified in our cohort as a risk factor for a Klebsiella liver abscess. The overall mortality was 2%.

Conclusion

Klebsiella is emerging as an important cause of liver abscesses. Malignancy may be an important risk factor for Klebsiella liver abscess.

Capsular types of Klebsiella pneumoniae revisited by wzc sequencing

Capsule is an important virulence factor in bacteria. A total of 78 capsular types have been identified in Klebsiella pneumoniae. However, there are limitations in current typing methods. We report here the development of a new genotyping method based on amplification of the variable regions of the wzc gene. Fragments corresponding to the variable region of wzc were amplified and sequenced from 76 documented capsular types of reference or clinical strains. The remaining two capsular types (reference strains K15 and K50) lacked amplifiable wzc genes and were proven to be acapsular. Strains with the same capsular type exhibited ≧94% DNA sequence identity across the variable region (CD1-VR2-CD2) of wzc. Strains with distinct K types exhibited <80% DNA sequence identity across this region, with the exception of three pairs of strains: K22/K37, K9/K45, and K52/K79. Strains K22 and K37 shared identical capsular polysaccharide synthesis (cps) genes except for one gene with a difference at a single base which resulted in frameshift mutation. The wzc sequences of K9 and K45 exhibited high DNA sequence similarity but possessed different genes in their cps clusters. K52 and K79 exhibited 89% wzc DNA sequence identity but were readily distinguished from each other at the DNA level; in contrast, strains with the same capsular type as K52 exhibited 100% wzc sequence identity. A total of 29 strains from patients with bacteremia were typed by the wzc system. wzc DNA sequences confirmed the documented capsular type for twenty-eight of these clinical isolates; the remaining strain likely represents a new capsular type. Thus, the wzc genotyping system is a simple and useful method for capsular typing of K. pneumoniae.

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.

An Increasing Prominent Disease of Klebsiella pneumoniae Liver Abscess: Etiology, Diagnosis, and Treatment

Background. During the past two decades, Klebsiella pneumoniae (K. pneumoniae) had surpassed Escherichia coli (E. coli) as the predominant isolate from patients with pyogenic liver abscess (PLA) in Asian countries, the United States, and Europe, and it tended to spread globally. Since the clinical symptom is atypical, the accurate and effective diagnosis and treatment of K. pneumoniae liver abscesses (KLAs) are very necessary. Methods. Here, we have comprehensively clarified the epidemiology and pathogenesis of KLA, put emphases on the clinical presentations especially the characteristic radiographic findings of KLA, and thoroughly elucidated the most effective antibiotic strategy of KLA. Results. K1 serotype is strongly associated with KLA especially in diabetic patients. Computed tomography (CT) and ultrasound (US) were two main diagnostic methods of KLA in the past. Most of KLAs have solitary, septal lobular abscesses in the right lobe of liver, and they are mainly monomicrobial. Broad-spectrum antibiotics combined with the US-guided percutaneous drainage of liver abscesses can increase their survival rates, but surgical intervention still has its irreplaceable position. Conclusion. The imaging features contribute to the early diagnosis, and the percutaneous intervention combined with an aminoglycoside plus either an extended-spectrum betalactam or a second- or third-generation cephalosporin is a timely and effective treatment of KLA.

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.

Characteristics and outcomes of culture-negative versus culture-positive severe sepsis

Introduction

Culture-negative sepsis is a common but relatively understudied condition. The aim of this study was to compare the characteristics and outcomes of culture-negative versus culture-positive severe sepsis.

Methods

This was a prospective observational cohort study of 1001 patients who were admitted to the medical intensive care unit (ICU) of a university hospital from 2004 to 2009 with severe sepsis. Patients with documented fungal, viral, and parasitic infections were excluded.

Results

There were 415 culture-negative patients (41.5%) and 586 culture-positive patients (58.5%). Gram-positive bacteria were isolated in 257 patients, and gram-negative bacteria in 390 patients. Culture-negative patients were more often women and had fewer comorbidities, less tachycardia, higher blood pressure, lower procalcitonin levels, lower Acute Physiology and Chronic Health Evaluation II (median 25.0 (interquartile range 19.0 to 32.0) versus 27.0 (21.0 to 33.0), P = 0.001) and Sequential Organ Failure Assessment scores, less cardiovascular, central nervous system, and coagulation failures, and less need for vasoactive agents than culture-positive patients. The lungs were a more common site of infection, while urinary tract, soft tissue and skin infections, infective endocarditis and primary bacteremia were less common in culture-negative than in culture-positive patients. Culture-negative patients had a shorter duration of hospital stay (12 days (7.0 to 21.0) versus 15.0 (7.0 to27.0), P = 0.02) and lower ICU mortality than culture-positive patients. Hospital mortality was lower in the culture-negative group (35.9%) than in the culture-positive group (44.0%, P = 0.01), the culture-positive subgroup, which received early appropriate antibiotics (41.9%, P = 0.11), and the culture-positive subgroup, which did not (55.5%, P < 0.001). After adjusting for covariates, culture positivity was not independently associated with mortality on multivariable analysis.

Conclusions

Significant differences between culture-negative and culture-positive sepsis are identified, with the former group having fewer comorbidities, milder severity of illness, shorter hospitalizations, and lower mortality.

Capsular serotypes and multilocus sequence types of bacteremic Klebsiella pneumoniae isolates associated with different types of infections

We investigated the epidemiology of different serotypes of Klebsiella pneumoniae isolates causing bacteremic liver abscess (LA) using multilocus sequence typing (MLST). MLST and molecular typing were performed for 41 K1 (19 LA), 37 K2 (5 LA), and 33 non-K1/K2 (6 LA) isolates that were derived from a previous one-year K. pneumoniae bacteremia cohort. Capsular serotypes and rmpA of these isolates were determined by polymerase chain reaction (PCR) methods. Among the 41 K1 isolates, 39 were ST23 and the remaining two isolates were ST23 single-locus variant. There were 11 STs among K2 isolates. ST65 was the most common (n = 10), followed by ST86, ST373, and ST375. Only ST65 (n = 3), ST373 (n = 1), and ST375 (n = 1) caused LA, and ST65 was a three-locus variant of ST23. For non-K1/K2 isolates, the ST types varied widely. ST218 (K57) was the most common type (n = 6, 18 %), and it was a single-locus variant of ST23 and caused two cases of LA. The existences of rmpA among serotypes varied (100 % for K1, 89 % for K2, and 55 % for non-K1/K2). For isolates causing LA, all of them were positive for rmpA. For non-K1/K2 isolates causing infections other than LA, the positivity of rmpA ranged from 0 % (biliary tree infection) to 67 % (pneumonia). In this one-year cohort, all K1 isolates were ST23 or its single-locus variants, but the composition of ST types among K2 isolates was quite variable. ST23 and its one- (ST1005 and ST218) and three-locus (ST65) variants comprised 80 % of isolates causing LA.

Draft Genome Sequence of Klebsiella pneumoniae Isolate PR04

Klebsiella pneumoniae PR04 was isolated from a patient hospitalized in Malaysia. The draft genome sequence of K. pneumoniae PR04 shows differences compared to the reference sequences of K. pneumoniae strains MGH 78578 and NTUH-K2044 in terms of their genomic structures.

Fusobacterium necrophorum: a rare cause of hepatic abscess in an immunocompetent individual

In the present case a 30-year-old African American man was admitted with fever and chills secondary to two large hepatic abscesses diagnosed on an ultrasound. The patient was started on antibiotics after blood cultures were drawn. Initially the abscess was drained and showed dramatic improvement upon repeat imaging. The blood cultures revealed Gram-negative rods that were identified as Fusobacterium necrophorum. At that time the patient was switched to levofloxacin and metronidazole based on sensitivities. On this new antibiotic regime the patient improved dramatically. After just 5 days the patient was discharged home on oral antibiotics and was scheduled to follow-up in 1 week. In the present case we present a healthy 30-year-old man with no significant co-morbidities who developed a hepatic abscess from F necrophorum but successfully recovered after appropriate antibiotic treatment.