Meeting the Challenge of Antimicrobial Resistance in Cirrhosis: The Invisible Threat That Lies Within

Infections in cirrhosis

Cirrhosis is an immune dysfunction state, and as such, patients with cirrhosis are susceptible to bacterial, fungal, and viral infections. Because of infection, these patients have a propensity to develop multiorgan failure, which is associated with high mortality. Bacterial infections are the most prevalent type of infection in patients with cirrhosis, with the prevalence of bacterial infections in patients admitted for an acute decompensating event ranging from 24% to 29%. Together with invasive fungal infections, bacterial infections are the most severe. Multidrug-resistant organisms have been evolving at a rapid and alarming rate around the world, which presents enormous challenges. The development of effective measures for the prevention, early detection, and treatment of infections in patients with cirrhosis is challenging, given the rising incidence of infections in this patient population.

The distribution profiles of tetracycline resistance genes in rice: Comparisons using four genotypes

The potential transmission of antibiotic resistance genes (ARGs) from the rhizosphere to plants and humans poses a significant concern. This study aims to investigate the distribution of tetracycline resistance genes (TRGs) in rice using four genotypes and identify the primary source of TRGs in grains. Quantitative polymerase chain reaction (qPCR) was employed to determine the abundance of seven TRGs and intI1 in four rice varieties and three partitions during the jointing and heading stages, respectively. The analysis of the bacterial community was conducted to elucidate the underlying mechanism of the profiles of TRGs. It was observed that tetZ was predominantly present in the rhizosphere and endoroot, whereas tetX became dominant in grains. The relative abundances of TRGs and intI1 exhibited significant variations across both the variety and partition. However, no significant differences were observed in grains, where the abundances of TRGs were several orders of magnitude lower compared to those in the rhizosphere. Nevertheless, the potential risk of the dissemination of TRGs to humans, particularly those carried by potential pathogens in grains, warrants attention. The increased likelihood of TRGs accumulation in the rhizosphere and endoroot of hybrid rice varieties, as opposed to japonica varieties, may be attributed to the heightened metabolic activities of their roots. The significant associations observed between intI1 and TRGs, coupled with the substantial alterations in potential hosts for intI1 across various treatments, indicate that intI1-mediated horizontal gene transfer plays a role in the diverse range of bacterial hosts for TRGs. The study also revealed that rhizosphere bacteria during the jointing stage serve as the primary contributors of TRGs in grains through the endoroot junction. The findings indicate that Japonica rice varieties exhibit superior control over TRGs compared to hybrid varieties, emphasizing the need for early interventions throughout the entire growth period of rice.

Antibiotic resistance in patients with liver cirrhosis: Prevalence and current approach to tackle

Regardless of etiology, complications with bacterial infection in patients with cirrhosis are reported in the range of 25%-46% according to the most recent data. Due to frequent episodes of bacterial infection and repetitive antibiotic treatment, most often with broad-spectrum gram negative coverage, patients with cirrhosis are at increased risk of encountering multidrug resistant bacteria, and this raises concern. In such patients, extended-spectrum beta-lactamase and AmpC-producing Enterobacterales, methicillin- or vancomycin-resistant Staphylococcus aureus, vancomycin-resistant Enterococci, carbapenem-resistant Pseudomonas aeruginosa, and Acinetobacter baumannii, all of which are difficult to treat, are the most common. That is why novel approaches to the prophylaxis and treatment of bacterial infections to avoid antibiotic resistance have recently been developed. At the same time, our knowledge of resistance mechanisms is constantly updated. This review summarizes the current situation regarding the burden of antibiotic resistance, including the prevalence and mechanisms of intrinsic and acquired resistance in bacterial species that most frequently cause complications in patients with liver cirrhosis and recent developments on how to deal with multidrug resistant bacteria.

Management of Multidrug-Resistant Infections in Cirrhosis

The World Health Organization describes antimicrobial resistance as one of the biggest threats to global health, food security, and development with indiscriminate use of antimicrobials globally driving the emergence of multidrug-resistant bacteria, resistant to 60% of antimicrobials in some countries. Infections with multidrug-resistant organisms (MDROs) have increased in recent decades in patients with cirrhosis, who are frequently prescribed antibiotics, regularly undergo invasive procedures such as large volume paracentesis, and have recurrent hospitalizations, posing a particular risk in this already immunocompromised cohort of patients. In this review, we explore mechanisms underlying this vulnerability to MDRO infection; the effect of bacterial infections on disease course in cirrhosis; prevalence of MDROs in patients with cirrhosis; outcomes following MDRO infection; fungal infections; antibiotics and their efficacy; and management of MDRO infections in terms of detection, antimicrobial and nonantimicrobial treatments, prophylaxis, antibiotic stewardship, the gut microbiome, and technological interventions.

Multiple bacterial virulence factors focused on adherence and biofilm formation associate with outcomes in cirrhosis

BACKGROUND & AIMS

Altered gut microbiota is associated with poor outcomes in cirrhosis, including infections and hepatic encephalopathy (HE). However, the role of bacterial virulence factors (VFs) is unclear. Aim: Define association of VFs with cirrhosis severity and infections, their linkage with outcomes, and impact of fecal microbiota transplant (FMT).

METHODS

VF abundances were determined using metagenomic analysis in stools from controls and cirrhosis patients (compensated, HE-only, ascites-only, both and infected). Patients were followed for 90-day hospitalizations and 1-year death. Stool samples collected before/after a placebo-controlled FMT trial were also analyzed. Bacterial species and VFs for all species and selected pathogens (Escherichia, Klebsiella, Pseudomonas, Staphylococcus, Streptococcus, and Enterococcus spp) were compared between groups. Multi-variable analyses were performed for clinical biomarkers and VFs for outcome prediction. Changes in VFs pre/post-FMT and post-FMT/placebo were analyzed. Results: We included 233 subjects (40 controls, 43 compensated, 30 HE-only, 20 ascites-only, 70 both, and 30 infected). Decompensated patients, especially those with infections, had higher VFs coding for siderophores, biofilms, and adhesion factors versus the rest. Biofilm and adhesion VFs from Enterobacteriaceae and Enterococcus spp associated with death and hospitalizations independent of clinical factors regardless of when all VFs or selected pathogens were analyzed. FMT was associated with reduced VF post-FMT versus pre-FMT and post-placebo groups.

CONCLUSIONS

Virulence factors from multiple species focused on adhesion and biofilms increased with decompensation and infections, associated with death and hospitalizations independent of clinical factors, and were attenuated with FMT. Strategies focused on targeting multiple virulence factors could potentially impact outcomes in cirrhosis.

PRESENTATIONS

Portions of this manuscript were an oral presentation in the virtual International Liver Congress 2021.

ABBREVIATIONS

VF: virulence factors, HE: hepatic encephalopathy, FMT: Fecal microbiota transplant, PPI: proton pump inhibitors, LPS: lipopolysaccharides, VFDB: Virulence factor database, OTU: operational taxonomic units, SBP: spontaneous bacterial peritonitis, UTI: urinary tract infections, MRSA: methicillin resistant Staphylococcus aureus, VRE: vancomycin-resistant Enterococcus, MAAsLin2: Microbiome Multivariable Associations with Linear Models, LPS: lipopolysaccharides, AKI: acute kidney injury.