Survival in the environment is a possible key factor for the expansion ofEscherichia colistrains producing extended-spectrum β-lactamases

An Overview of the Antimicrobial Activity of Polymeric Nanoparticles Against Enterobacteriaceae

Bacterial resistance is considered one of the most important public health problems of the century, due to the ability of bacteria to rapidly develop resistance mechanisms, which makes it difficult to treat infections, leading to a high rate of morbidity and mortality. Based on this, several options are being sought as an alternative to currently available treatments, with a particular focus on nanotechnology. Nanomaterials have important potential for use in medical interventions aimed at preventing, diagnosing and treating numerous diseases by directing the delivery of drugs. This review presents data on the use of polymeric nanoparticles having in vitro and in vivo activity against bacteria belonging to the Enterobacteriaceae family.

Impact of Sediment Concentration on the Survival of Wastewater-Derived blaCTX-M-15-Producing E. coli, and the Implications for Dispersal into Estuarine Waters

The environmental cycling of antibiotic-resistant bla_CTX-M-15-producing E. coli following release from wastewater treatment plants is a major public health concern. This study aimed to (i) assess the impact of sediment concentrations on the rate of their inactivation following release from human wastewater into freshwater, and (ii) simulate their subsequent dispersal to the nearby coastline during a “worst-case” event where heavy rainfall coincided with high spring tide in the Conwy Estuary, North Wales. Freshwater microcosms of low, medium and high turbidity were inoculated with bla_CTX-M-15-producing E. coli, then exposed to ultraviolet (UV) radiation. Typical regional wintertime exposure to UV was found to be insufficient to eradicate E. coli, and in highly turbid water, many bacteria survived simulated typical regional summertime UV exposure. Modelling results revealed that bla_CTX-M-15-producing E. coli concentrations reduced downstream from the discharge source, with ~30% of the source concentration capable of dispersing through the estuary to the coast, taking ~36 h. Offshore, the concentration simulated at key shellfisheries and bathing water sites ranged from 1.4% to 10% of the upstream input, depending on the distance offshore and tidal regime, persisting in the water column for over a week. Our work indicates that the survival of such organisms post-release into freshwater is extended under typical wintertime conditions, which could ultimately have implications for human health.

Bathroom contamination by antibiotic-resistant Enterobacterales (ESBLPE and CPE): an experimental study

BACKGROUND

Extended-spectrum β-lactamase-producing Enterobacterales (ESBLPE) and carbapenemase-producing Enterobacterales (CPE) cause serious infections. Their presence in urine may lead to environmental contamination potentially responsible for cross-transmission.

AIM

To evaluate the level of spraying and contamination after emptying urine in the toilet and rinsing in the sink, a common practice in the healthcare setting.

METHODS

For each test, the procedure was similar: seat raised, emptying urinal bottle into the toilet at the height of the bowl, rinsing in the sink and flushing. To study splash-drops, water and fluorescein were mixed in the urinal bottle. In each area, the splash-drops frequency and level were assessed with UV. To study contamination, three ESBLPE and one CPE were diluted in saline, 10⁶/mL. Contamination was assessed by sampling before, immediately after and 3 h after the test. The swabs were cultured and the colonies counted and identified.

FINDINGS

The areas at the highest risk of spraying were the toilet bowl contour (N = 36/36), the underside of the toilet seat (N = 34) and the inside of the sink (N = 34). Except for gloves (N = 14), there was low clothing contamination. The most frequently contaminated areas were inside the sink (40/48), where the highest levels of contamination were found (14/48).

CONCLUSION

Emptying the urinal bottles in the toilet followed by sink rinsing is associated with a significant risk of projection and contamination, depending on the area (highest risk at the sink), but the bacteria did not survive beyond 3 h. This practice, which carries a risk of cross-transmission, should be reviewed.

MOLECULAR CHARACTERIZATION OF FECAL ESCHERICHIA COLI ISOLATED FROM ZOO ANIMALS

Accredited zoos and animal parks play an important role in animal health research and conservation, providing important insights on matters of public health including zoonotic infectious diseases and antimicrobial resistance (AMR). The emergence and spread of AMR is a complex phenomenon that jeopardizes human and animal health and also threatens the long-term survival of endangered species. The presence of β-lactamases in clinical isolates is particularly significant as they can jeopardize the efficacy of critically important antimicrobials. Although the presence of β-lactamases and extended-spectrum β-lactamases (ESBLs) producing Enterobacteriaceae in zoo animals has been reported, data are not available for northern European countries. In addition, few data are available on phylogenetic grouping of Escherichia coli isolated from zoo animals that can provide additional information on the host-bacterium relationship and on the pathogenicity of isolates. This study aimed to characterize fecal E. coli isolated from 33 healthy zoo animals from 22 species in Ireland, using conventional and molecular microbiological methods. All E. coli isolates were ampicillin resistant, but combined resistance to amoxicillin and clavulanic acid was not detected. Three E. coli isolates sampled from one Amur tiger, one Bornean orangutan, and one Southern white rhino were multidrug resistant, and blaTEM was detected in E. coli recovered from the Amur tiger and the Bornean orangutan. Other β-lactamases, including ESBLs and AmpCs and plasmid-mediated mcr-1 and mcr-2, were not detected. Overall, E. coli isolates investigated were susceptible to the majority of the antimicrobials tested, and only two animals shed E. coli carrying β-lactamase-encoding genes. The majority of isolates belonged to phylogenetic group B1. The screening of the AMR phenotype and genotype of zoo animal E. coli provides useful data that is relevant to antimicrobial stewardship in the zoo veterinary services and relevant to the bank of knowledge needed for tackling AMR.

Evaluation of an in vitro model with a novel statistical approach to measure differences in bacterial survival of extended-spectrum β-lactamase-producing Escherichia coli on an inanimate surface

Background

The role of environmental contamination in the transmission of Enterobacteriaceae is increasingly recognized. However, factors influencing the duration of survival in the environment have not yet been extensively studied. In this study, we developed and evaluated an in vitro model with a novel statistical approach to accurately measure differences in bacterial survival, that can be used to model the effects of multiple factors/conditions in future experiments.

Methods

Two extended-spectrum β-lactamase (ESBL)-producing Escherichia coli (E. coli) isolates were used for this in vitro experiment: a CTX-M-15-producing E. coli sequence type (ST) 131 and a CTX-M-1-producing E. coli ST10 isolate. Each strain was 1:1 diluted in sterile water, sterile saline or sheep blood. Cover glasses (18 × 18 mm) were inoculated with the dilution and subsequently kept at room temperature. Bacterial survival on the glasses was determined hourly during the first day, once daily during the following 6 days, and from day 7 on, once weekly up to 100 days. The experiment was repeated six times for each strain, per suspension fluid.

Results

Viable bacteria could be detected up to 70 days. A biphasic survival curve for all suspension fluids was observed, whereby there was a rapid decrease in the number of viable bacteria in the first 7 h, followed by a much slower decrease in the subsequent days.

Conclusions

We found a difference in survival probability between E. coli ST10 and ST131, with a higher proportion of viable bacteria remaining after 7 h for ST131, particularly in sheep blood.

Clonal expansion of environmentally-adapted Escherichia coli contributes to propagation of antibiotic resistance genes in beef cattle feedlots

Livestock wastewater lagoons represent important environmental reservoirs of antibiotic resistance genes (ARGs), although factors contributing to their proliferation within these reservoirs remain poorly understood. Here, we characterized Escherichia coli from feedlot cattle feces and associated wastewater lagoons using CRISPR1 subtyping, and demonstrated that while generic E. coli were genetically diverse, populations were dominated by several 'feedlot-adapted' CRISPR types (CTs) that were widely distributed throughout the feedlot. Moreover, E. coli bearing beta-lactamase genes, which confer reduced susceptibility to third-generation cephalosporin's, predominantly belonged to these feedlot-adapted CTs. Remarkably, the genomic region containing the CRISPR1 allele was more frequently subject to genetic exchange among wastewater isolates compared to fecal isolates, implicating this region in environmental adaptation. This allele is proximal to the mutS-rpoS-nlpD region, which is involved in regulating recombination barriers and adaptive stress responses. There were no loss-of-function mutS or rpoS mutations or beneficial accessory genes present within the mutS-rpoS-nlpD region that would account for increased environmental fitness among feedlot-adapted isolates. However, comparative sequence analysis revealed that protein sequences within this region were conserved among most feedlot-adapted CTs, but not transient fecal CTs, and did not reflect phylogenetic relatedness, implying that adaptation to wastewater environments may be associated with genetic variation related to stress resistance. Collectively, our findings suggest adaptation of E. coli to feedlot environments may contribute to propagation of ARGs in wastewater lagoons.

A new drug design strategy: Killing drug resistant bacteria by deactivating their hypothetical genes

Despite that a bacterial genome is complicated by large numbers of horizontally transferred (HT) genes and function unknown hypothetical (FUN) genes, the Genic-Transcriptional-Stop-Signals-Ratio (TSSR) of a genome shows that HT and FUN genes are complementary to all other genes in the genome. When HT or certain FUN genes are omitted from the Escherichia coli K-12 genome, its Genomic-TSSR value becomes totally incomparable to other E. coli strains. The Genic-TSSR correlation tree of a pathogen shows that some FUN genes would form a unique cluster. Removing these genes by site-specific mutation or gene-knockout should lead to the demise of this pathogen.

Level of decontamination after washing textiles at 60°C or 70°C followed by tumble drying

BACKGROUND

Several major outbreaks in healthcare facilities have occurred with the emergence of multi-resistant bacteria. A possible route for dissemination is the hospital textiles and inadequate laundering of them. The aim of this study was to develop an easy-to-use method for simulating the laundering process of hospital textiles, and thereafter apply the method when evaluating the decontaminating efficacy of two different washing temperatures.

METHODS

The laundering process, including tumble drying, took place at two professional laundries. Enterococcus faecium was used as bioindicator.

RESULTS

The results showed that a lowering of the washing temperature from 70°C to 60°C did not affect the decontamination efficacy; the washing cycle alone reduced the number of bacteria with 3-5 log10 CFU, whereas the following tumble drying reduced the bacterial numbers with another 3-4 log10 CFU, yielding the same final result independent of washing temperature. Without tumble drying, there was an obvious risk of adding non-fermenting gram-negative bacteria to the fabric. These bacteria originated from the washing cycle.

CONCLUSION

A simple method to simulate hospital laundering was developed. To save energy, it is possible to use a washing temperature of 60°C, but the washing cycle should be followed by tumble drying, and the whole laundering process needs to be monitored to maintain sufficient textile hygiene.