Bacterial meningitis in cirrhotic patients: case series and description of the prognostic role of acute renal failure

Management of bacterial and fungal infections in end stage liver disease and liver transplantation: Current options and future directions

Patients with liver cirrhosis are susceptible to infections due to various mechanisms, including abnormalities of humoral and cell-mediated immunity and occurrence of bacterial translocation from the intestine. Bacterial infections are common and represent a reason for progression to liver failure and increased mortality. Fungal infections, mainly caused by Candida spp., are often associated to delayed diagnosis and high mortality rates. High level of suspicion along with prompt diagnosis and treatment of infections are warranted. Bacterial and fungal infections negatively affect the outcomes of liver transplant candidates and recipients, causing disease progression among patients on the waiting list and increasing mortality, especially in the early post-transplant period. Abdominal, biliary tract, and bloodstream infections caused by Gram-negative bacteria [e.g., Enterobacteriaceae and Pseudomonas aeruginosa (P. aeruginosa)] and Staphylococcus spp. are commonly encountered in liver transplant recipients. Due to frequent exposure to broad-spectrum antibiotics, invasive procedures, and prolonged hospitalizations, these patients are especially at risk of developing infections caused by multidrug resistant bacteria. The increase in antimicrobial resistance hampers the choice of an adequate empiric therapy and warrants the knowledge of the local microbial epidemiology and the implementation of infection control measures. The main characteristics and the management of bacterial and fungal infections in patients with liver cirrhosis and liver transplant recipients are presented.

The Road to Infection: Host-Microbe Interactions Defining the Pathogenicity of Streptococcus bovis/Streptococcus equinus Complex Members

The Streptococcus bovis/Streptococcus equinus complex (SBSEC) comprises several species inhabiting the animal and human gastrointestinal tract (GIT). They match the pathobiont description, are potential zoonotic agents and technological organisms in fermented foods. SBSEC members are associated with multiple diseases in humans and animals including ruminal acidosis, infective endocarditis (IE) and colorectal cancer (CRC). Therefore, this review aims to re-evaluate adhesion and colonization abilities of SBSEC members of animal, human and food origin paired with genomic and functional host-microbe interaction data on their road from colonization to infection. SBSEC seem to be a marginal population during GIT symbiosis that can proliferate as opportunistic pathogens. Risk factors for human colonization are considered living in rural areas and animal-feces contact. Niche adaptation plays a pivotal role where Streptococcus gallolyticus subsp. gallolyticus (SGG) retained the ability to proliferate in various environments. Other SBSEC members have undergone genome reduction and niche-specific gene gain to yield important commensal, pathobiont and technological species. Selective colonization of CRC tissue is suggested for SGG, possibly related to increased adhesion to cancerous cell types featuring enhanced collagen IV accessibility. SGG can colonize, proliferate and may shape the tumor microenvironment to their benefit by tumor promotion upon initial neoplasia development. Bacteria cell surface structures including lipotheichoic acids, capsular polysaccharides and pilus loci (pil1, pil2, and pil3) govern adhesion. Only human blood-derived SGG contain complete pilus loci and other disease-associated surface proteins. Rumen or feces-derived SGG and other SBSEC members lack or harbor mutated pili. Pili also contribute to binding to fibrinogen upon invasion and translocation of cells from the GIT into the blood system, subsequent immune evasion, human contact system activation and collagen-I-binding on damaged heart valves. Only SGG carrying complete pilus loci seem to have highest IE potential in humans with significant links between SGG bacteremia/IE and underlying diseases including CRC. Other SBSEC host-microbe combinations might rely on currently unknown mechanisms. Comparative genome data of blood, commensal and food isolates are limited but required to elucidate the role of pili and other virulence factors, understand pathogenicity mechanisms, host specificity and estimate health risks for animals, humans and food alike.

Risk factors and outcome of bacterial infections in cirrhosis

Viable and non-viable pathological bacterial translocation promote a self-perpetuating circle of dysfunctional immune activation and systemic inflammation facilitating infections and organ failure in advanced cirrhosis. Bacterial infections and sepsis are now recognized as a distinct stage in the natural progression of chronic liver disease as they accelerate organ failure and contribute to the high mortality observed in decompensated cirrhosis. The increasing knowledge of structural, immunological and hemodynamic pathophysiology in advanced cirrhosis has not yet translated into significantly improved outcomes of bacterial infections over the last decades. Therefore, early identification of patients at the highest risk for developing infections and infection-related complications is required to tailor the currently available measures of surveillance, prophylaxis and therapy to the patients in need in order to improve the detrimental outcome of bacterial infections in cirrhosis.

Management of infections in cirrhotic patients: report of a consensus conference

The statements produced by the consensus conference on infection in end-stage liver disease promoted by the Italian Association for the Study of the Liver, are here reported. The topics of epidemiology, risk factors, diagnosis, prophylaxis, and treatment of infections in patient with compensated and decompensated liver cirrhosis were reviewed by a scientific board of experts who proposed 26 statements that were graded according to level of evidence and strength of recommendation, and approved by an independent jury. Each topic was explored focusing on the more relevant clinical questions. By systematic literature search of available evidence, comparison and discussion of expert opinions, pertinent statements answering specific questions were presented and approved. Short comments were added to explain the basis for grading evidence particularly on case of controversial areas.

Bacterial infections other than spontaneous bacterial peritonitis in cirrhosis

Cirrhotic patients are immunocompromised with a high risk of infection. Proinflammatory cytokines and hemodynamic circulation derangement further facilitate the development of serious consequences of infections. Other than spontaneous bacterial peritonitis, bacteremia and bacterial infections of other organ systems are frequently observed. Gram-negative enteric bacteria are the most common causative organism. Other bacterial infections, such as enterococci, Vibrio spp., Aeromonas spp., Clostridium spp., Listeria monocytogenes, Plesiomonas shigelloides and Mycobacterium tuberculosis are more prevalent and more virulent. Generally, intravenous third generation cephalosporins are recommended as empirical antibiotic therapy. Increased incidences of gram-positive and drug-resistant organisms have been reported, particularly in hospital-acquired infections and in patients receiving quinolones prophylaxis. This review focuses upon epidemiology, microbiology, clinical features and treatment of infections in cirrhosis other than spontaneous bacterial peritonitis, including pathogen-specific and liver disease-specific issues.