The new epidemiology of nosocomial bacterial infections in cirrhosis: therapeutical implications

Derivation of a score to predict infection due to multi-drug resistant Pseudomonas aeruginosa: A tool for guiding empirical antibiotic treatment

BACKGROUND

Multidrug-resistant Pseudomonas aeruginosa (MDR-PSA) constitutes an emerging health problem. A predictive score of MDR-PSA infection would let early adaptation of empirical antibiotic therapy.

METHODS

We performed a single-center case-control (1:2) retrospective study including 100 patients with MDR-PSA and 200 with non-MDR-PSA infection. Cases and controls were matched by site of infection, clinical characteristics and immunosuppression. A point risk score for prediction of MDR-PSA infection was derived from a logistic regression model. Secondary outcomes (clinical improvement, complications and discharge) were also compared.

RESULTS

Cases with MDR-PSA infection were younger than controls (67.5 vs. 73.0 years; P=0.031) and have more frequently cirrhosis (9% vs. 2%; P=0.005). Independent risk factors for MDR-PSA infection were prior antibiotic treatment (80% vs. 50.5%; P<0.001), prior colonization with MDR bacteria (41% vs. 13.5%; P<0.001), hospital-acquired infection (63% vs. 47%; P=0.009), and septic shock at diagnosis (33% vs. 14%; P<0.001). Adequate therapy was less frequent in MDR-PSA infections (31% vs. 66.5% for empirical therapy; P<0.001). The risk score included: previous MDR-PSA isolation (11 points), prior antibiotic use (3 points), hospital-acquired infection (2 points), and septic shock at diagnosis (2 points). It showed an area under the curve of 0.755 (95% CI: 0.70-0.81) and allowed to classify individual risk into various categories: 0-2 points (<20%), 3-5 points (25-45%), 7-11 points (55-60%), 13-16 points (75-87%) and a maximum of 18 points (93%).

CONCLUSIONS

Infections due to MDR-PSA have a poorer prognosis than those produced by non-MDR-PSA. Our score could guide empirical therapy for MDR-PSA when P. aeruginosa is isolated.

Sustained impact of nosocomial-acquired spontaneous bacterial peritonitis in different stages of decompensated liver cirrhosis

Background & aims

Bacterial infections, in particular a spontaneous bacterial peritonitis (SBP), are a major threat in patients with liver cirrhosis. Recently, it has been shown that the impact on mortality might be underestimated by established risk-scores. Onset of infection was suggested to define a distinct stage of cirrhosis. However, it remains unclear whether all stages of decompensated cirrhosis are equally affected. Moreover, if there is such a distinct stage, it must be determined whether it is reversible after the infection has resolved.

In this study we aimed to further analyze the impact of a current as well as a resolved SBP in different stages of decompensated liver cirrhosis.

Methods

A number of 579 patients with liver cirrhosis and ascites were included. MELD-score was used to determine the stage of liver disease. Low (<15), intermediate (15–25) and high (>25) MELD-groups were compared. Patients were followed up for 90 days. Primary endpoint was overall mortality. Statistical analyses were performed using the log-rank test, Cox regression and competing risk analysis.

Results

Mortality was significantly higher in patients with nosocomial-acquired SBP (nSBP) compared to patients without SBP (p<0.001;HR = 2.05). However, the most prominent difference in mortality was documented in the intermediate MELD-group (nSBP: p = 0.02;HR = 2.10). Importantly, mortality in nSBP patients remained increased even after the initial nSBP episode had resolved (p<0.01;HR = 1.90). Again, this was only significant in those with intermediate MELD-scores (p = 0.02;HR = 2.28). While a current as well as a resolved nSBP were significantly linked to a higher mortality, neither of them did increase the likelihood for liver transplantation.

Conclusions

Development of nSBP is independently associated with increased mortality supporting the concept of a distinct status of cirrhosis. Importantly, the prognosis remains unfavorable even after resolution of nSBP. This could be particularly relevant for patients with intermediate MELD-scores, who have limited chances for a donor liver.

Causative agents and outcome of spontaneous bacterial peritonitis in cirrhotic patients: community-acquired versus nosocomial infections

Background

Spontaneous bacterial peritonitis (SBP) is a serious complication and common cause of death in patients with liver cirrhosis. This study was conducted to compare the microbiological characteristics, drug resistance, and treatment outcomes for nosocomial SBP and community-acquired SBP.

Methods

A retrospective study was performed on 334 patients with culture-positive SBP at Beijing Youan Hospital, China, between January 2012 and December 2016. The medical records for these patients were reviewed, and their clinical and laboratory data were analyzed.

Results

A total of 155 (46.4%) patients with nosocomial SBP and 179 (53.6%) with community-acquired SBP were included in this study. From the patients’ ascitic fluids, 334 pathogenic strains, including 178 Gram-negative bacterial strains, 138 Gram-positive bacterial strains and 18 other microbial strains were isolated. E. coli was the major pathogen (24.3%), followed by Klebsiella pneumoniae (12.0%) and Enterococcus faecium (10.5%). The proportion of Enterococcus was significantly higher in the patients with nosocomial SBP (6.1% vs. 27.7%, P < 0.001) than in the patients with community-acquired SBP. The main pathogens isolated from the nosocomial infections were significantly more resistant to the first-line recommended drug. Compared with community-acquired SBP, nosocomial SBP had a poorer outcome (36.8% vs. 24.6%; P = 0.016). The independent predictors for 30-day mortality included nosocomial infection, Child-Pugh classification, hepatocellular carcinoma, renal failure and hepatic encephalopathy.

Conclusion

Gram-negative bacteria were the major pathogens involved in SBP in the cirrhotic patients. The strains isolated from the patients with nosocomial SBP displayed higher drug resistance than those isolated from patients with community-acquired SBP. Compared with community-acquired SBP, nosocomial SBP had a poorer outcome. When choosing drug treatments, the acquisition site of infection and the local epidemiological situation should be taken into account.

Noninvasive screening identifies patients at risk for spontaneous bacterial peritonitis caused by multidrug-resistant organisms

Background and aims

Spontaneous bacterial peritonitis (SBP) is a severe complication of decompensated cirrhosis. The prevalence of multidrug-resistant organisms (MDROs) in patients with cirrhosis is increasing. Identification of patients at risk for SBP due to MDROs (ie, SBP with the evidence of MDROs or Stenotrophomonas maltophilia in ascitic culture, MDRO-SBP) is crucial to the early adaptation of antibiotic treatment in such patients. We therefore investigated whether MDROs found in ascitic cultures can also be found in specimens determined by noninvasive screening procedures.

Patients and methods

This retrospective study was conducted at the liver center of the University Hospital Frankfurt, Germany. Between 2011 and 2016, patients with cirrhosis were included upon diagnosis of SBP and sample collection of aerobic/anaerobic ascitic cultures. Furthermore, the performance of at least one complete MDRO screening was mandatory for study inclusion.

Results

Of 133 patients diagnosed with SBP, 75 (56.4%) had culture-positive SBP and 22 (16.5%) had MDRO-SBP. Multidrug-resistant Escherichia coli (10/22; 45.5%) and vancomycin-resistant enterococci (7/22; 36.4%) resembled the major causatives of MDRO-SBP. Rectal swabs identified MDROs in 17 of 22 patients (77.3%) who developed MDRO-SBP with a time-dependent sensitivity of 77% and 87% after 30 and 90 days upon testing, while negative predictive value was 83% and 76%, respectively. The majority of patients were included from intensive care unit or intermediate care unit.

Conclusion

MDRO screening may serve as a noninvasive diagnostic tool to identify patients at risk for MDRO-SBP. Patients with decompensated cirrhosis should be screened for MDROs from the first day of inpatient treatment onward.

Sepsis in cirrhosis: emerging concepts in pathogenesis, diagnosis and management

Infections and sepsis are more common in cirrhotic than in the general population and constitute the commonest cause of sudden worsening and death. The diagnosis of systemic inflammatory syndrome and sepsis are challenging in cirrhotics due to an underlying a state of hyperdynamic circulation. Further, poor nutritional and bone marrow reserves lead to modest host immune response, the so called immunoparalysis state and the outcome of antibiotic therapy is suboptimal. In this review, a comprehensive description of current and emerging concepts in the pathogenesis and diagnosis of sepsis with importance to current and novel biomarkers for diagnosis of sepsis in cirrhosis is presented. Furthermore, novel treatment options and preventive strategies are discussed to improve the overall survival.

Extensively drug-resistant bacteria are an independent predictive factor of mortality in 130 patients with spontaneous bacterial peritonitis or spontaneous bacteremia

AIM: To evaluate the epidemiology and outcomes of culture-positive spontaneous bacterial peritonitis (SBP) and spontaneous bacteremia (SB) in decompensated cirrhosis.

METHODS: We prospectively collected clinical, laboratory characteristics, type of administered antibiotic, susceptibility and resistance of bacteria to antibiotics in one hundred thirty cases (68.5% males) with positive ascitic fluid and/or blood cultures during the period from January 1, 2012 to May 30, 2014. All patients with SBP had polymorphonuclear cell count in ascitic fluid > 250/mm³. In patients with SB a thorough study did not reveal any other cause of bacteremia. The patients were followed-up for a 30-d period following diagnosis of the infection. The final outcome of the patients was recorded in the end of follow-up and comparison among 3 groups of patients according to the pattern of drug resistance was performed.

RESULTS: Gram-positive-cocci (GPC) were found in half of the cases. The most prevalent organisms in a descending order were Escherichia coli (33), Enterococcus spp (30), Streptococcus spp (25), Klebsiella pneumonia (16), S. aureus (8), Pseudomanas aeruginosa (5), other Gram-negative-bacteria (GNB) (11) and anaerobes (2). Overall, 20.8% of isolates were multidrug-resistant (MDR) and 10% extensively drug-resistant (XDR). Health-care-associated (HCA) and/or nosocomial infections were present in 100% of MDR/XDR and in 65.5% of non-DR cases. Meropenem was the empirically prescribed antibiotic in HCA/nosocomial infections showing a drug-resistance rate of 30.7% while third generation cephalosporins of 43.8%. Meropenem was ineffective on both XDR bacteria and Enterococcus faecium (E. faecium). All but one XDR were susceptible to colistin while all GPC (including E. faecium) and the 86% of GNB to tigecycline. Overall 30-d mortality was 37.7% (69.2% for XDR and 34.2% for the rest of the patients) (log rank, P = 0.015). In multivariate analysis, factors adversely affecting outcome included XDR infection (HR = 2.263, 95%CI: 1.005-5.095, P = 0.049), creatinine (HR = 1.125, 95%CI: 1.024-1.236, P = 0.015) and INR (HR =1.553, 95%CI: 1.106-2.180, P = 0.011).

CONCLUSION: XDR bacteria are an independent life-threatening factor in SBP/SB. Strategies aiming at restricting antibiotic overuse and rapid identification of the responsible bacteria could help improve survival.

Multiresistant bacterial infections in liver cirrhosis: Clinical impact and new empirical antibiotic treatment policies

Recently, important changes have been reported regarding the epidemiology of bacterial infections in liver cirrhosis. There is an emergence of multiresistant bacteria in many European countries and also worldwide, including the United States and South Korea. The classic empirical antibiotic treatment (third-generation cephalosporins, e.g., ceftriaxone, cefotaxime or amoxicillin-clavulanic acid) is still effective in infections acquired in the community, but its failure rate in hospital acquired infections and in some health-care associated infections is high enough to ban its use in these settings. The current editorial focuses on the different epidemiology of bacterial infections in cirrhosis across countries and on its therapeutic implications.

New determinants of prognosis in bacterial infections in cirrhosis

Despite major advances in the knowledge and management of liver diseases achieved in recent decades, decompensation of cirrhosis still carries a high burden of morbidity and mortality. Bacterial infections are one of the main causes of decompensation. It is very important for clinical management to be aware of the population with the highest risk of poor outcome. This review deals with the new determinants of prognosis in patients with cirrhosis and bacterial infections reported recently. Emergence of multiresistant bacteria has led to an increasing failure rate of the standard empirical antibiotic therapy recommended by international guidelines. Moreover, it has been recently reported that endothelial dysfunction is associated with the degree of liver dysfunction and, in infected patients, with the degree of sepsis. It has also been reported that relative adrenal insufficiency is frequent in the non-critically ill cirrhotic population and it is associated with a higher risk of developing infection, severe sepsis, hepatorenal syndrome and death. We advise a change in the standard empirical antibiotic therapy in patients with high risk for multiresistant infections and also to take into account endothelial and adrenal dysfunction in prognostic models in hospitalized patients with decompensated cirrhosis.

Bacterial infections in cirrhosis: a position statement based on the EASL Special Conference 2013

Bacterial infections are very common and represent one of the most important reasons of progression of liver failure, development of liver-related complications, and mortality in patients with cirrhosis. In fact, bacterial infections may be a triggering factor for the occurrence of gastrointestinal bleeding, hypervolemic hyponatremia, hepatic encephalopathy, kidney failure, and development of acute-on-chronic liver failure. Moreover, infections are a very common cause of repeated hospitalizations, impaired health-related quality of life, and increased healthcare costs in cirrhosis. Bacterial infections develop as a consequence of immune dysfunction that occurs progressively during the course of cirrhosis. In a significant proportion of patients, infections are caused by gram-negative bacteria from intestinal origin, yet gram-positive bacteria are a frequent cause of infection, particularly in hospitalized patients. In recent years, infections caused by multidrug-resistant bacteria are becoming an important clinical problem in many countries. The reduction of the negative clinical impact of infections in patients with cirrhosis may be achieved by a combination of prophylactic measures, such as administration of antibiotics, to reduce the occurrence of infections in high-risk groups together with early identification and management of infection once it has developed. Investigation on the mechanisms of altered gut microflora, translocation of bacteria, and immune dysfunction may help develop more effective and safe methods of prevention compared to those that are currently available. Moreover, research on biomarkers of early infection may be useful in early diagnosis and treatment of infections. The current manuscript reports an in-depth review and a position statement on bacterial infections in cirrhosis.

Bacterial infections in cirrhosis

Bacterial infections occur in 25-35 % of cirrhotics admitted to hospital. Health-care associated and hospital acquired (nosocomial) infections are the most common epidemiology, with community acquired infections less common (15-30 %). Spontaneous bacterial peritonitis and urinary infections are the most common sites, with spontaneous bacteremia, pneumonia, cellulitis and other sites being less common. The risk of infection is increased among subjects with more severe liver disease and an infection in the past 6 months. Bacteria are isolated from approximately half of patients with a clinical diagnosis of infection. Gram-negative enterobacteriaceae are the most common organisms among community acquired infections; Gram-positive cocci are the most common organisms isolated among subjects with nosocomial infections. Up to 30 % of hospital associated infections are with multidrug resistant bacteria. Consequently, empiric antibiotic therapy that is recommended for community acquired infections is often inadequate for nosocomial infections. Infections worsen liver function. In-hospital and 1-year mortality of cirrhotics with infections is significantly higher than among cirrhotics without infection. In-hospital complications of infections, such as severe sepsis and septic shock, and mortality, are increased among subjects with multidrug-resistant infections as compared with cirrhotics with susceptible bacteria. Short-term antibiotic prophylaxis of cirrhotics with upper gastrointestinal bleeding and long-term antibiotic prophylaxis of selected cirrhotics with spontaneous bacterial peritonitis reduces infections and improves survival. Albumin administration to cirrhotics with SBP and evidence of advanced liver disease improves survival. The benefit of albumin administration to cirrhotics with infections other than SBP is under investigation.

Changing options for prevention and treatment of infections in cirrhosis

OPINION STATEMENT

Bacterial infections are more frequent and severe in cirrhosis. Most prevalent infections are spontaneous bacterial peritonitis (SBP) and urinary infections followed by pneumonia, cellulitis and bacteremia. Cirrhosis increases the risk of sepsis, severe sepsis and death. Early diagnosis and adequate treatment of infections is essential in the management of cirrhotic patients. Recent data show that currently recommended empirical antibiotic therapy, mainly based on the use of β-lactams, is effective in community-acquired infections, but frequently fails in nosocomial and healthcare-associated infections. A marked increase in the prevalence of multidrug resistant (MDR) bacteria in the healthcare environment explains this finding. Patients developing nosocomial infections or with extended lengths of hospitalization are at higher risk for second infections that are associated with poor prognosis. Antibiotic strategies should therefore be selected according to the type, severity and site of acquisition of infection, and be adapted to the local epidemiological pattern of antibiotic resistance. Treatment of MDR bacteria requires the use of broader spectrum antibiotics (carbapenems) or those active against specific resistant bacteria (glycopeptides, linezolid, daptomycin, amikacin, colistin). Restriction of antibiotic prophylaxis to the high-risk populations, prevention of antibiotic overuse, and early de-escalation policies are also mandatory to prevent the spread of MDR bacteria in cirrhosis.

Patterns of antimicrobial resistance in the causative organisms of spontaneous bacterial peritonitis: a single centre, six-year experience of 1981 samples

Background/Aims. Spontaneous bacterial peritonitis (SBP) is one of the leading causes of morbidity and mortality in patients with cirrhosis. This study aims to determine the microbial agents of SBP and the pattern of antibiotic resistance, in a large number of ascitic samples. Methodology. In a cross-sectional, single center, hospital based study, 1981 consecutive ascitic fluid samples were recruited from 2005 to 2011. Samples were dichotomized into three-year periods, in order to assess the trend of resistance to the first-line empirical antibiotics. Results. SBP was found in 482 (24.33%) of samples, of which 314 (65.15%) were culture positive. The most prevalent isolated pathogen was E. coli (33.8%), followed by staphylococcus aureus (8.9%) and Enterococcus (8.6%). No significant changes in the proportion of gram-negative/gram-positive infections occurred during this period. A percentage of resistant strains to cefotaxime (62.5%, 85.7%), ceftazidim (73%, 82.1%), ciprofloxacin (30, 59.8%), ofloxacin (36.8%, 50%), and oxacilin (35%, 51.6%) were significantly increased. E. coli was most sensitive to imipenem, piperacillin-tazobactam, amikacin, ceftizoxime, and gentamicin. Conclusions. The microbial aetiology of SBP remains relatively constant. However, the resistance rate especially to the first-line recommended antibiotics was significantly increased. This pattern must be watched closely and taken into account in empirical antibiotic treatment.