Biofilm reduction potential of 0.02% polyhexanide irrigation solution in several types of urethral catheters

Background Long-term use of urethral catheters is associated with high risk of urinary tract infection (UTI) and blockage. Microbial biofilms are a common cause of catheter blockage, reducing their lifetime and significantly increasing morbidity of UTIs. A 0.02% polyhexanide irrigation solution developed for routine mechanical rinsing shows potential for bacterial decolonization of urethral catheters and has the potential to reduce or prevent biofilm formation. Methods Using an in vitro assay with standard market-leading types of catheters artificially contaminated with clinically relevant bacteria, assays were carried out to evaluate the biofilm reduction and prevention potential of a 0.02% polyhexanide solution versus no intervention (standard approach) and irrigation with saline solution (NaCl 0.9%). The efficiency of decolonization was measured through microbial plate count and membrane filtration. Results Irrigation using a 0.02% polyhexanide solution is suitable for the decolonization of a variety of transurethral catheters. The effect observed is significant compared to irrigation with 0.9% saline solution (p = 0.002) or no treatment (p = 0.011). No significant difference was found between irrigation with 0.9% saline solution and no treatment (p = 0.74). Conclusions A 0.02% polyhexanide solution is able to reduce bacterial biofilm from catheters artificially contaminated with clinically relevant bacteria in vitro. The data shows a reduction of the viability of thick bacterial biofilms in a variety of commercially available urinary catheters made from silicone, latex-free silicone, hydrogel-coated silicone and PVC. Further research is required to evaluate the long-term tolerability and efficacy of polyhexanide in clinical practice.

Comprehensive genome data analysis establishes a triple whammy of carbapenemases, ICEs and multiple clinically relevant bacteria

Carbapenemases inactivate most β-lactam antibiotics, including carbapenems, and have frequently been reported among Enterobacteriaceae , Acinetobacter spp. and Pseudomonas spp. Traditionally, the horizontal gene transfer of carbapenemase-encoding genes (CEGs) has been linked to plasmids. However, given that integrative and conjugative elements (ICEs) are possibly the most abundant conjugative elements among prokaryotes, we conducted an in silico analysis to ascertain the likely role of ICEs in the spread of CEGs among all bacterial genomes (n=182 663). We detected 17 520 CEGs, of which 66 were located within putative ICEs among several bacterial species (including clinically relevant bacteria, such as Pseudomonas aeruginosa , Klebsiella pneumoniae and Escherichia coli ). Most CEGs detected within ICEs belong to the IMP, NDM and SPM metallo-beta-lactamase families, and the serine beta-lactamase KPC and GES families. Different mechanisms were likely responsible for acquisition of these genes. The majority of CEG-bearing ICEs belong to the MPFG, MPFT and MPFF classes and often encode resistance to other antibiotics (e.g. aminoglycosides and fluoroquinolones). This study provides a snapshot of the different CEGs associated with ICEs among available bacterial genomes and sheds light on the underappreciated contribution of ICEs to the spread of carbapenem resistance globally.

ESKAPE Bacteria and Extended-Spectrum-β-Lactamase-Producing Escherichia coli Isolated from Wastewater and Process Water from German Poultry Slaughterhouses

ABSTRACT The wastewater of livestock slaughterhouses is considered a source of antimicrobial-resistant bacteria with clinical relevance and may thus be important for their dissemination into the environment. To get an overview of their occurrence and characteristics, we investigated process water (n = 50) from delivery and unclean areas as well as wastewater (n = 32) from the in-house wastewater treatment plants (WWTPs) of two German poultry slaughterhouses (slaughterhouses S1 and S2). The samples were screened for ESKAPE bacteria (Enterococcus spp., Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter spp.) and Escherichia coli. Their antimicrobial resistance phenotypes and the presence of extended-spectrum-β-lactamase (ESBL), carbapenemase, and mobilizable colistin resistance genes were determined. Selected ESKAPE bacteria were epidemiologically classified using different molecular typing techniques. At least one of the target species was detected in 87.5% (n = 28/32) of the wastewater samples and 86.0% (n = 43/50) of the process water samples. The vast majority of the recovered isolates (94.9%, n = 448/472) was represented by E. coli (39.4%), the A. calcoaceticus-A. baumannii (ACB) complex (32.4%), S. aureus (12.3%), and K. pneumoniae (10.8%), which were widely distributed in the delivery and unclean areas of the individual slaughterhouses, including their wastewater effluents. Enterobacter spp., Enterococcus spp., and P. aeruginosa were less abundant and made up 5.1% of the isolates. Phenotypic and genotypic analyses revealed that the recovered isolates exhibited diverse resistance phenotypes and β-lactamase genes. In conclusion, wastewater effluents from the investigated poultry slaughterhouses exhibited clinically relevant bacteria (E. coli, methicillin-resistant S. aureus, K. pneumoniae, and species of the ACB and Enterobacter cloacae complexes) that contribute to the dissemination of clinically relevant resistances (i.e., blaCTX-M or blaSHV and mcr-1) in the environment. IMPORTANCE Bacteria from livestock may be opportunistic pathogens and carriers of clinically relevant resistance genes, as many antimicrobials are used in both veterinary and human medicine. They may be released into the environment from wastewater treatment plants (WWTPs), which are influenced by wastewater from slaughterhouses, thereby endangering public health. Moreover, process water that accumulates during the slaughtering of poultry is an important reservoir for livestock-associated multidrug-resistant bacteria and may serve as a vector of transmission to occupationally exposed slaughterhouse employees. Mitigation solutions aimed at the reduction of the bacterial discharge into the production water circuit as well as interventions against their further transmission and dissemination need to be elaborated. Furthermore, the efficacy of in-house WWTPs needs to be questioned. Reliable data on the occurrence and diversity of clinically relevant bacteria within the slaughtering production chain and in the WWTP effluents in Germany will help to assess their impact on public and environmental health.

Hitchhikers in Honey: An investigation of the inhibitory mechanisms of bacteria found in honey

Honey has a stable physiochemical composition that contributes to its long shelf life and has been noted as an antimicrobial substance for centuries. Although it is common knowledge that honey affords some antimicrobial properties, the specific mechanisms behind this remain elusive. This paper hypothesizes that the microorganisms in certain raw honeys contribute towards their antimicrobial properties. In our study, we analyzed several raw and processed honey samples to determine their microbial constituents. The antimicrobial potential of the isolated microbes was tested using several clinically relevant bacteria including Escherichia coli, Staphylococcus aureus, Staphylococcus epidermidis and Pseudomonas aeruginosa. Of the tested honeys, Manuka (New Zealand) and Wildflower honey (Tennessee, USA) contained microorganisms exhibiting antimicrobial activity. All the isolated colonies grew on MacConkey and Mannitol agar and generated bands for the 16S rRNA gene implying that they were bacteria. This paper concludes that bacteria isolated from honey could be a new area of research within the topic of antimicrobial honey samples.

Comprehensive genome data analysis establishes a triple whammy of carbapenemases, ICEs and multiple clinically-relevant bacteria

Carbapenemases inactivate most β-lactam antibiotics, including carbapenems and have been frequently reported among Enterobacteriaceae, Acinetobacter spp. and Pseudomonas spp. Traditionally, the horizontal gene transfer of carbapenemase encoding genes (CEGs) has been linked to plasmids. However, given that integrative and conjugative elements (ICEs) are possibly the most abundant conjugative elements among prokaryotes, we conducted an in-silico analysis to ascertain the likely role of ICEs in the spread of CEGs among all bacterial genomes (n=182,663). We detected 17,520 CEGs, of which 66 were located within putative ICEs among several bacterial species (including clinically-relevant bacteria as Pseudomonas aeruginosa, Klebsiella pneumoniae and Escherichia coli). Most CEGs detected within ICEs belong to the IMP, NDM and SPM metallo-beta-lactamase families, and the serine beta-lactamase KPC and GES families. Different mechanisms were likely responsible for acquisition of these genes. The majority of CEG-bearing ICEs belong to the MPFG, MPFT and MPFF classes and often encode resistance to other antibiotics (e.g., aminoglycosides and fluoroquinolones). This study provides a snapshot of the different CEGs associated with ICEs among available bacterial genomes and sheds light on the underappreciated contribution of ICEs to the spread of carbapenem resistance globally.Author NotesAll supporting data has been provided within the article or through supplementary data files. Supplementary material is available with the online version of this article.Impact StatementCarbapenems are commonly used to treat severe infections in humans. Resistance is often mediated by carbapenemases. These enzymes degrade carbapenems and are frequently present in plasmids. Here, we demonstrate that common carbapenemase-encoding genes (CEGs) found in clinical isolates (e.g. blaKPC, blaGES, blaIMP, blaNDM, blaVIM) can also be located within integrative and conjugative elements (ICEs). CEG-bearing ICEs belong to three mating-pair formation families. These mobile elements may be particularly important in bacteria where plasmids do not seem to play a significant role in the spread of antibiotic resistance genes, as Pseudomonas spp. This study considerably expands the knowledge of the repertoire of CEGs-bearing ICEs among clinically-relevant bacterial pathogens, such as Pseudomonas aeruginosa, Klebsiella pneumoniae and Escherichia coli.Data SummaryAll the bacterial genomes scanned in this study have been deposited previously in the National Center for Biotechnology Information genome database and are listed on the supplementary tables. The extracted 66 ICEs in fasta format and the outputs for the profile HMMs scanned on the 386 putative MGEs identified in this study are deposited on figshare at https://figshare.com/projects/_Comprehensive_genome_data_analysis_establishes_a_triple_whammy_of_carbapenemases_ICEs_and_multiple_clinically-relevant_bacteria/78369.