Systemic infection is an important risk factor for the development cognitive impairment and neurodegeneration in older people. Animal experiments show that systemic challenges with live bacteria... Show moreSystemic infection is an important risk factor for the development cognitive impairment and neurodegeneration in older people. Animal experiments show that systemic challenges with live bacteria cause a neuro-inflammatory response, but the effect of age on this response in these models is unknown. Young (2 months) and middle-aged mice (13-14 months) were intraperitoneally challenged with live Escherichia coli (E. coli) or saline. The mice were sacrificed at 2, 3 and 7 days after inoculation; for all time points, the mice were treated with ceftriaxone (an antimicrobial drug) at 12 and 24 h after inoculation. Microglial response was monitored by immunohistochemical staining with an ionized calcium-binding adaptor molecule 1 (Iba-1) antibody and flow cytometry, and inflammatory response by mRNA expression of pro- and anti-inflammatory mediators. We observed an increased microglial cell number and moderate morphologically activated microglial cells in middle-aged mice, as compared to young mice, after intraperitoneal challenge with live E. coli. Flow cytometry of microglial cells showed higher CD45 and CD11b expressions in middle-aged infected mice compared to young infected mice. The brain expression levels of pro-inflammatory genes were higher in middle-aged than in young infected mice, while middle-aged infected mice had similar expression levels of these genes in the systemic compartment. We conclude that systemic challenge with live bacteria causes an age-dependent neuro-inflammatory and microglial response. Our data show signs of an age-dependent disconnection of the inflammatory transcriptional signature between the brain and the systemic compartment. Show less
The carriage of two important pathogens of pigs, that is enterotoxigenic Escherichia coli (ETEC) and Clostridioides difficile, was investigated in 104 cloacal samples from wild griffon vultures ... Show moreThe carriage of two important pathogens of pigs, that is enterotoxigenic Escherichia coli (ETEC) and Clostridioides difficile, was investigated in 104 cloacal samples from wild griffon vultures (Gyps fulvus) fed on pig carcasses at supplementary feeding stations (SFS), along with their level of antimicrobial resistance (AMR). E. coli was isolated from 90 (86.5%) samples, but no ETEC was detected, likely because ETEC fimbriae confer the species specificity of the pathogen. Resistance to at least one antimicrobial agent was detected in 89.9% of E. coli isolates, with AMR levels being extremely high (>70%) for tetracycline and streptomycin and very high (>50%) for ampicillin and sulfamethoxazole-trimethoprim. Resistance to other critically important antimicrobials such as colistin and extended-spectrum cephalosporins was 2.2% and 1.1%, respectively, and was encoded by the mcr-1 and bla(SHV-12) genes. Multidrug resistance was displayed by 80% of the resistant E. coli, and bla(SHV-12) gene shared plasmid with other AMR genes. In general, resistance patterns in E. coli from vultures mirrored those found in pigs. Clostridioides difficile was detected in three samples (2.9%); two of them belonged to PCR ribotype 078 and one to PCR ribotype 126, both commonly found in pigs. All C. difficile isolates were characterized by a moderate-to-high level of resistance to fluoroquinolones and macrolides but susceptible to metronidazole or vancomycin, similar to what is usually found in C. difficile isolates from pigs. Thus, vultures may contribute somewhat to the environmental dissemination of some pig pathogens through their acquisition from pig carcasses and, more importantly, of AMR for antibiotics of critical importance for humans. However, the role of vultures would likely be much lesser than that of disposing pig carcasses at the SFS. The monitoring of AMR, and particularly of colistin-resistant and ESBL-producing E. coli, should be considered in pig farms used as sources of carcasses for SFS. Show less
Hoogland, I.C.M.; Westhoff, D.; Engelen-Lee, J.Y.; Melief, J.; Seron, M.V.; Houben-Weerts, J.H.M.P.; ... ; Beek, D. van de 2018
Antimicrobial resistance of bacteria is a worldwide and ever-growing problem, directly linked to the use of antimicrobial drugs. Resistant bacteria emerge under the selective pressure of... Show moreAntimicrobial resistance of bacteria is a worldwide and ever-growing problem, directly linked to the use of antimicrobial drugs. Resistant bacteria emerge under the selective pressure of antibiotics. In hospitals, where large-scale usage of antibiotics is common, bacteria frequently become resistant to several antibiotics which causes serious problems for the treatment of patients with infections by these microorganisms. Well-known (multi)-resistant bacteria causing problems in many countries all over the world are methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci, penicillin-resistant pneumococci, extended-spectrum betalactamase-producing Klebsiella pneumoniae, carbapenem-resistant Acinetobacter baumannii, and multiresistant Mycobacterium tuberculosis Show less
In bacteria, what __drives__ the process of cell division is unknown. Possibly, forces generated by an internal protein ring (termed __the Z-ring__) are responsible for the division process, but... Show moreIn bacteria, what __drives__ the process of cell division is unknown. Possibly, forces generated by an internal protein ring (termed __the Z-ring__) are responsible for the division process, but direct evidence is lacking. Here we describe the development of a method to measure forces in a single dividing bacterium. Using optical tweezers, forces can be measured on optically trapped micron-sized beads. To attach such a bead to a living bacterium, one of its outer membrane proteins is engineered to present a binding epitope on the cell surface. We show that it is possible to attach a bead to this __molecular handle__ via a DNA-molecule, and characterize the strength of this molecular construct. Finally, we show that genetic fusion of the surface exposed protein domain to an internal domain with mid-cell affinity can alter the localization pattern of the exposed domain. Our findings suggest that it is possible to create a fusion protein that exposes a binding epitope and localizes specifically to the division site. Show less
