Leitbakteria of microbial biofilm communities causing occlusion of biliary stents

Clinical characteristics, aetiology and mortality/recurrence risk factors of acute cholangitis in patients with and without biliary stent

OBJECTIVES

Acute cholangitis is one of the most frequent complications in patients carrying biliary stents. The aim of our study is to analyze the demographic and clinical characteristics, as well as the microbiological profile and evolution of patients with acute bacteremic cholangitis, comparing them based upon they were or not biliary stent carriers.

METHODS

We performed a retrospective analysis of all consecutive patients over 18 years-old with a stent placement in our center between 2008 and 2017 were included. We compared them with our prospective cohort of patients with a diagnosis of acute bacteremic cholangitis. Primary outcome was 30-day mortality. Secondary outcome was clinical cure at day 7, 14-day mortality and 90-day recurrence.

RESULTS

Two hundred and seventy-three patients were analyzed, including 156 in the stent-related (SR) and 117 in the stent not-related (SNR) group, respectively. Stent-related colangitis patients were younger, with more comorbidities and with a greater severity of infection. Escherichia coli and Klebsiella pneumonia were the most frequent isolation. Enterococcus spp. was the third most frequent isolation in SR group but were uncommon in SNR patients; where E. coli was the most prevalent microorganism. Septic shock (HR 3.44, 95% [CI 1.18-8.77]), inadequate empirical treatment (HR 2.65, 95% CI [1.38-.7.98]) and advanced neoplasia (HR 2.41, 95% CI [1.55-6.44]) were independent 30-day mortality risk factors. The 90-day recurrence rate significantly higher in those patients with stent-related cholangitis (29% vs. 13%, p=0.016) and stent replacement was associated with lower recurrence rate (HR 0.38, 95% CI [0.11-0.77]).

CONCLUSIONS

Clinical and microbiological profile, as well as outcome of patients with SR and SNR cholangitis were different. In SR group, recurrence rate was high and stent replacement was associated with a lower risk.

Clinical characteristics, aetiology and mortality/recurrence risk factors of acute cholangitis in patients with and without biliary stent

OBJECTIVES

Acute cholangitis is one of the most frequent complications in patients carrying biliary stents. The aim of our study is to analyze the demographic and clinical characteristics, as well as the microbiological profile and evolution of patients with acute bacteremic cholangitis, comparing them based upon they were or not biliary stent carriers.

METHODS

We performed a retrospective analysis of all consecutive patients over 18 years-old with a stent placement in our center between 2008 and 2017 were included. We compared them with our prospective cohort of patients with a diagnosis of acute bacteremic cholangitis. Primary outcome was 30-day mortality. Secondary outcome was clinical cure at day 7, 14-day mortality and 90-day recurrence.

RESULTS

Two hundred and seventy-three patients were analyzed, including 156 in the stent-related (SR) and 117 in the stent not-related (SNR) group, respectively. Stent-related colangitis patients were younger, with more comorbidities and with a greater severity of infection. Escherichia coli and Klebsiella pneumonia were the most frequent isolation. Enterococcus spp. was the third most frequent isolation in SR group but were uncommon in SNR patients; where E. coli was the most prevalent microorganism. Septic shock (HR 3.44, 95% [CI 1.18-8.77]), inadequate empirical treatment (HR 2.65, 95% CI [1.38-.7.98]) and advanced neoplasia (HR 2.41, 95% CI [1.55-6.44]) were independent 30-day mortality risk factors. The 90-day recurrence rate significantly higher in those patients with stent-related cholangitis (29% vs. 13%, p=0.016) and stent replacement was associated with lower recurrence rate (HR 0.38, 95% CI [0.11-0.77]).

CONCLUSIONS

Clinical and microbiological profile, as well as outcome of patients with SR and SNR cholangitis were different. In SR group, recurrence rate was high and stent replacement was associated with a lower risk.

Colonization, resistance to bile, and virulence properties of Escherichia coli strains: Unusual characteristics associated with biliary tract diseases

Escherichia coli is the species that is most frequently isolated from bile of patients with biliary tract diseases. This study was aimed to investigate any association between resistance and virulence properties of these isolates with occurrence of the diseases. A total of 102 bile samples were obtained from patients subjected to endoscopic retrograde cholangiopancreatography for different biliary diseases. Clinical data were collected and culture of the bile samples was done on selective media. Resistance of characterized Escherichia coli isolates to deoxycholate sodium (0-7%) and nineteen antibiotics was determined and PCR using 16 pairs of primers targeting stx1, stx2, exhA, eae, bfp, agg, pcvd432, lt, st, ipaH, pic, pet, ast, set, sen, and cdtB genes was done. Our results showed a statistically significant association between E. coli colonization and existence of common bile duct and gallbladder stones (p value 0.028). Out of the 22 E. coli strains (22/102) multidrug resistance phenotype was present in 95.45%. None of the strains belonged to common E. coli pathotypes. However, bfp + EhxA-hly, bfp + astA, bfp + EhxA-hly + pic, and EhxA-hly + pic + astA, bfp, and astA genotypes were detected in these strains. bfp (7/22, 31.8%) and astA (5/22, 22.7%) were among most frequent virulence factors in these strains. Results of this study showed significant association between colonization of E. coli and choledocholithiasis. Unusual existence of virulence gene combinations in these strains and their resistance to DOC and multiple classes of antibiotics could be considered as possible causes of their persistence in this harsh microenvironment.

Epidemiology and Resistance Patterns of Bacterial and Fungal Colonization of Biliary Plastic Stents: A Prospective Cohort Study

Background

Plastic stents used for the treatment of biliary obstruction will become occluded over time due to microbial colonization and formation of biofilms. Treatment of stent-associated cholangitis is often not effective because of inappropriate use of antimicrobial agents or antimicrobial resistance. We aimed to assess the current bacterial and fungal etiology of stent-associated biofilms, with particular emphasis on antimicrobial resistance.

Methods

Patients with biliary strictures requiring endoscopic stent placement were prospectively enrolled. After the retrieval of stents, biofilms were disrupted by sonication, microorganisms were cultured, and isolates were identified by matrix-associated laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry and/or biochemical typing. Finally, minimum inhibitory concentrations (MICs) were determined for various antimicrobial agents. Selected stents were further analyzed by fluorescence in situ hybridization (FISH).

Results

Among 120 patients (62.5% males, median age 64 years) with biliary strictures (35% malignant, 65% benign), 113 double pigtail polyurethane and 100 straight polyethylene stents were analyzed after a median indwelling time of 63 days (range, 1–1274 days). The stent occlusion rate was 11.5% and 13%, respectively, being associated with a significantly increased risk of cholangitis (38.5% vs. 9.1%, P<0.001). Ninety-five different bacterial and 13 fungal species were detected; polymicrobial colonization predominated (95.8% vs. 4.2%, P<0.001). Enterococci (79.3%), Enterobacteriaceae (73.7%), and Candida spp. (55.9%) were the leading pathogens. Candida species were more frequent in patients previously receiving prolonged antibiotic therapy (63% vs. 46.7%, P = 0.023). Vancomycin-resistant enterococci accounted for 13.7%, extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae with co-resistance to ciprofloxacin accounted for 13.9%, and azole-resistant Candida spp. accounted for 32.9% of the respective isolates.

Conclusions

Enterococci and Candida species play an important role in the microbial colonization of biliary stents. Therefore, empirical antimicrobial treatment of stent-associated cholangitis should be guided toward enterococci, Enterobacteriaceae, streptococci, anaerobes, and Candida. To determine causative pathogens, an accurate microbiological analysis of the extracted stent(s) may be helpful.

Role of preoperative biliary stents, bile contamination and antibiotic prophylaxis in surgical site infections after pancreaticoduodenectomy

BACKGROUND

The routine use of preoperative biliary drainage before pancreaticoduodenectomy (PD) remains controversial. This observational retrospective study compared stented and non-stented patients undergoing PD to assess any differences in post-operative morbidity and mortality.

METHODS

A total of 180 consecutive patients who underwent PD and had intra-operative bile cultures performed between January 2010 and February 2013 were retrospectively identified. All patients received peri-operative intravenous antibiotic prophylaxis, primarily cefazolin.

RESULTS

Overall incidence of post-operative surgical complications was 52.3 %, with no difference between stented and non-stented patients (53.4 % vs. 51.1 %; p = 0.875). However, stented patients had a significantly higher incidence of deep incisional surgical site infections (SSIs) (p = 0.038). In multivariate analysis, biliary stenting was confirmed as a risk factor for deep incisional SSIs (p = 0.044). Significant associations were also observed for cardiac disease (p = 0.010) and BMI ≥25 kg/m(2) (p = 0.045). Enterococcus spp. were the most frequent bacterial isolates in bile (74.5 %) and in drain fluid (69.1 %). In antimicrobial susceptibilty testing, all Enterococci isolates were cefazolin-resistant.

CONCLUSION

Given the increased risk of deep incisional SSIs, preoperative biliary stenting in patients underging PD should be used only in selected patients. In stented patients, an antibiotic with anti-enterococcal activity should be chosen for PD prophylaxis.

Short-Term Rhizosphere Effect on Available Carbon Sources, Phenanthrene Degradation, and Active Microbiome in an Aged-Contaminated Industrial Soil

Over the last decades, understanding of the effects of plants on soil microbiomes has greatly advanced. However, knowledge on the assembly of rhizospheric communities in aged-contaminated industrial soils is still limited, especially with regard to transcriptionally active microbiomes and their link to the quality or quantity of carbon sources. We compared the short-term (2-10 days) dynamics of bacterial communities and potential PAH-degrading bacteria in bare or ryegrass-planted aged-contaminated soil spiked with phenanthrene, put in relation with dissolved organic carbon (DOC) sources and polycyclic aromatic hydrocarbon (PAH) pollution. Both resident and active bacterial communities (analyzed from DNA and RNA, respectively) showed higher species richness and smaller dispersion between replicates in planted soils. Root development strongly favored the activity of Pseudomonadales within the first 2 days, and of members of Actinobacteria, Caulobacterales, Rhizobiales, and Xanthomonadales within 6-10 days. Plants slowed down the dissipation of phenanthrene, while root exudation provided a cocktail of labile substrates that might preferentially fuel microbial growth. Although the abundance of PAH-degrading genes increased in planted soil, their transcription level stayed similar to bare soil. In addition, network analysis revealed that plants induced an early shift in the identity of potential phenanthrene degraders, which might influence PAH dissipation on the long-term.

Do different implant surfaces exposed in the oral cavity of humans show different biofilm compositions and activities?

Osseointegrated dental implants play an important role in restorative dentistry. However, plaque accumulation may cause inflammatory reactions around the implants, sometimes leading to implant failure. In this in vivo study the influence of two physical hard coatings on bacterial adhesion was examined in comparison with a pure titanium surface. Thin glass sheets coated with titanium nitride (TiN), zirconium nitride (ZrN) or pure titanium were mounted on removable intraoral splints in two adults. After 60 h of intraoral exposure, the biofilms were analyzed to determine the number of bacteria, the types of bacteria [by applying single-strand conformation polymorphism (SSCP analysis) of 16S rRNA genes], and whether or not the bacteria were active (by SSCP analysis of 16S rRNA). The results showed that bacterial cell counts were higher on the pure titanium-coated glass sheets than on the glass sheets coated with TiN or ZrN. The lowest number of bacterial cells was present on theZrN-coated glass. However, the metabolic activity (RNA fingerprints) of bacteria on TiN- and ZrN-coated glass sheets seemed to be lower than the activity of bacteria on the titanium-coated surfaces, whereas SSCP fingerprints based on 16S rDNA revealed that the major 16S bands are common to all of the fingerprints, independently of the surface coating.

Exploring prokaryotic diversity: there are other molecular worlds

Prokaryotes are the major source of biological diversity on earth. This is not simply because of the large number of species present, or because of their diverse growth conditions and environmental niches populated by them, but because of the wealth of genes, metabolic pathways and molecular processes that are only found in prokaryotic cells. Therefore, Bacteria and Archaea (and their phages) cannot be considered any longer as miniaturized models of Eukaryotes, but as a genuine source of unique biological processes that are mediated by unique sets of genes and molecular devices. A true understanding of complex biological phenomena will require a deeper knowledge of this vast prokaryotic world. The second European Molecular Biology Organization (EMBO) conference on Molecular Microbiology entitled 'Exploring Prokaryotic Diversity' explored many aspects of this newly emerging interest in the prokaryotic world.