Iron Is Critical for Mucosal-Associated Invariant T Cell Metabolism and Effector Functions.

Mucosal-Associated Invariant T (MAIT) cells are a population of innate T cells that play a critical role in host protection against bacterial and viral pathogens. Upon activation, MAIT cells can rapidly respond via both TCR-dependent and -independent mechanisms, resulting in robust cytokine production. The metabolic and nutritional requirements for optimal MAIT cell effector responses are still emerging. Iron is an important micronutrient and is essential for cellular fitness, in particular cellular metabolism. Iron is also critical for many pathogenic microbes, including those that activate MAIT cells. However, iron has not been investigated with respect to MAIT cell metabolic or functional responses. In this study, we show that human MAIT cells require exogenous iron, transported via CD71 for optimal metabolic activity in MAIT cells, including their production of ATP. We demonstrate that restricting iron availability by either chelating environmental iron or blocking CD71 on MAIT cells results in impaired cytokine production and proliferation. These data collectively highlight the importance of a CD71-iron axis for human MAIT cell metabolism and functionality, an axis that may have implications in conditions where iron availability is limited.

Toward a Universal Unit for Quantification of Antibiotic Resistance Genes in Environmental Samples.

Surveillance of antibiotic resistance genes (ARGs) has been increasingly conducted in environmental sectors to complement the surveys in human and animal sectors under the "One-Health" framework. However, there are substantial challenges in comparing and synthesizing the results of multiple studies that employ different test methods and approaches in bioinformatic analysis. In this article, we consider the commonly used quantification units (ARG copy per cell, ARG copy per genome, ARG density, ARG copy per 16S rRNA gene, RPKM, coverage, PPM, etc.) for profiling ARGs and suggest a universal unit (ARG copy per cell) for reporting such biological measurements of samples and improving the comparability of different surveillance efforts.

Longitudinal analysis of client appointment adherence under Universal Test and Treat strategy: A stepped-wedge trial.

OBJECTIVES: Universal Test and Treat (UTT) strategies are being adopted across sub-Saharan Africa based on clinical benefits to morbidity and mortality and to attain targets of the Joint United Nations Programme on HIV/AIDS (UNAIDS). Universal Test and Treat is expected to change the client population at clinics, due to more asymptomatic HIV clients initiating antiretroviral therapy (ART). We assessed the impact of UTT on client appointment adherence at 14 government-managed health facilities in Eswatini's public sector health system. METHODS: We assessed the impact of UTT on client adherence to appointment schedules from 2014 to 2017 in a stepped-wedge trial. Repeated measures analysis was used to assess adherence to each scheduled appointment (primary definition: presenting for care within 7 days after the scheduled appointment), adjusting for time, age, sex, stage, marital status, ART status and facility. RESULTS: Among 3354 clients (62.1% female; 57.4% < 35 years), a median (interquartile range) of 10 (6-15) appointments were scheduled during follow-up. In a multivariable-adjusted model, appointment adherence was significantly greater in clients who were female [odds ratio (OR) = 1.38, 95% confidence interval (CI): 1.25-1.52], older (e.g. 40 to < 50 years vs. < 20 years; OR = 1.45, 95% CI: 1.00-2.09), married (OR = 1.31, 95% CI: 1.19-1.44), had lower WHO stage at study enrolment (1-2 vs. 3-4: OR = 1.26, 95% CI: 1.13-1.41), and were currently on ART (OR = 3.55, 95% CI: 2.62-4.82). However, UTT strategy was not significantly associated with client adherence to scheduled appointments (OR = 1.02, 95% CI: 0.72-1.45). CONCLUSIONS: Despite transitioning to UTT, there was no change in visit adherence, a reassuring finding given the large volume of clients currently being initiated at earlier stages of HIV.

The Impact of Immediate Initiation of Antiretroviral Therapy on Patients' Healthcare Expenditures: A Stepped-Wedge Randomized Trial in Eswatini.

Immediate initiation of antiretroviral therapy (ART) for all people living with HIV has important health benefits but implications for the economic aspects of patients' lives are still largely unknown. This stepped-wedge cluster-randomized controlled trial aimed to determine the causal impact of immediate ART initiation on patients' healthcare expenditures in Eswatini. Fourteen healthcare facilities were randomly assigned to transition at one of seven time points from the standard of care (ART eligibility below a CD4 count threshold) to the immediate ART for all intervention (EAAA). 2261 patients living with HIV were interviewed over the study period to capture their past-year out-of-pocket healthcare expenditures. In mixed-effects regression models, we found a 49% decrease (RR 0.51, 95% CI 0.36, 0.72, p < 0.001) in past-year total healthcare expenditures in the EAAA group compared to the standard of care, and a 98% (RR 0.02, 95% CI 0.00, 0.02, p < 0.001) decrease in spending on private and traditional healthcare. Despite a higher frequency of HIV care visits for newly initiated ART patients, immediate ART initiation appears to have lowered patients' healthcare expenditures because they sought less care from alternative healthcare providers. This study adds an important economic argument to the World Health Organization's recommendation to abolish CD4-count-based eligibility thresholds for ART.

RESUMEN: El inicio inmediato de la terapia antirretroviral (TAR) para todas las personas que viven con VIH tiene importantes beneficios para la salud, pero aún se desconocen las implicaciones en el aspecto económico. Este ensayo controlado aleatorizado por clústers (CRT por sus siglas en inglés) por grupos en distintas etapas pretende determinar el impacto del inicio inmediato de la TAR en los gastos sanitarios de los pacientes en Eswatini. Catorce centros sanitarios fueron asignados aleatoriamente a la transición en uno de los siete periodos de la asistencia estándar (elegibilidad para la TAR en niveles definidos de recuento de CD4) a la intervención de TAR inmediato para todos (EAAA). Se entrevistó a 2.261 pacientes con VIH a lo largo del estudio para conocer sus gastos sanitarios del año anterior. Según los modelos de regresión de efectos mixtos, se observó un descenso del 49% (RR: 0,51; IC del 95%: 0,36, 0,72; p<0,001) en el gasto sanitario total del año anterior en el grupo de la EAAA, y un descenso del 98% (RR 0,02; IC del 95%: 0,00, 0,02; p<0,001) en el gasto en asistencia sanitaria privada y tradicional. A pesar de una mayor frecuencia de visitas deatención de VIH para los pacientes que recién comenzaron laTAR, la aplicación inmediata de laTAR redujo los gastos sanitarios de los pacientes dado que buscaron menos atención de proveedores de asistencia sanitaria alternativos. Este estudio añade un importante argumento económico a la recomendación de la Organización Mundial de la Salud de abolir las restricciones de elegibilidad para la terapia antirretroviral basados en el recuento de CD4.

Getting to 90-90-90: Experiences from the MaxART Early Access to ART for All (EAAA) Trial in Eswatini.

PURPOSE OF REVIEW: The MaxART Consortium-led by the Eswatini Ministry of Health-implemented multiple interventions between 2012 and 2017 to achieve UNAIDS 90-90-90 targets. We summarize key findings from community outreach strategies in support of the first 90 goal, and from the Early Access to ART for All (EAAA) trial on the implementation of a "Treat All" strategy to achieve the second and third 90 goals within a government-managed public health system. RECENT FINDINGS: The MaxART Consortium demonstrated that "Fast Track," a problem-solving approach, was effective at increasing testing coverage in the community. Compared with baseline data at 3 months prior to the start of the Fast Track, there was a 273% proportional increase in HIV tests conducted among adolescent males, adolescent females, and adult men, and 722% over baseline for adolescent males. The MaxART EAAA trial further showed that implementation of the Treat All policy was associated with significant two-fold shorter time from enrollment into care to ART initiation than under the standard CD4+ cell threshold-based treatment guidelines. Finally, through the MaxART trial, Eswatini was able to identify areas for further investment, including addressing the system-side barriers to routine viral load monitoring, and designing and implementing innovative community-based approaches to reach individuals who were not more routinely accessing HIV testing and counseling services. As low- and middle-income countries adopt the Treat All approach in their national HIV care and treatment guidelines, further implementation science research is needed to understand and address the system-level barriers to achieving the benefits of Treat All for HIV-infected individuals and those at risk.

Plant variety and soil type influence Escherichia coli O104:H4 strain C227/11ϕcu adherence to and internalization into the roots of lettuce plants.

Human disease outbreaks caused by pathogenic Escherichia coli are increasingly associated with the consumption of contaminated fresh produce. Internalization of enteroaggregative/enterohemorrhagic E. coli (EAEC/EHEC) strains into plant tissues may present a serious threat to public health. In the current study, the ability of the fluorescing Shiga toxin-negative E. coli O104:H4 strain C227/11ϕcu/pKEC2 to adhere to and to internalize into the roots of Lactuca sativa and Valerianella locusta grown in diluvial sand (DS) and alluvial loam (AL) was investigated. In parallel, the soil microbiota was analyzed by partial 16S rRNA gene sequencing. The experiments were performed in a safety level 3 greenhouse to simulate agricultural practice. The adherence of C227/11ϕcu/pKEC2 to the roots of both plant varieties was increased by at least a factor three after incubation in DS compared to AL. Compared to V. locusta, internalization into the roots of L. sativa was increased 12-fold in DS and 108-fold in AL. This demonstrates that the plant variety had an impact on the internalization ability, whereas for a given plant variety the soil type also affected bacterial internalization. In addition, microbiota analysis detected the inoculated strain and showed large differences in the bacterial composition between the soil types.

Antibiotic resistance in grass and soil.

Antibiotic resistance is currently one of the greatest threats to human health. The global overuse of antibiotics in human medicine and in agriculture has resulted in the proliferation and dissemination of a multitude of antibiotic resistance genes (ARGs). Despite a large proportion of antibiotics being used in agriculture, little is understood about how this may contribute to the overall antibiotic resistance crisis. The use of manure in agriculture is a traditional and widespread practice and is essential for returning nutrients to the soil; however, the impact of continuous manure application on the environmental microbiome and resistome is unknown. The use of antibiotics in animal husbandry in therapeutic and sub-therapeutic doses creates a selective pressure for ARGs in the gut microbiome of the animal, which is then excreted in the faeces. Therefore, the application of manure to agricultural land is a potential route for the transmission of antibiotic-resistant bacteria from livestock to crops, animals and humans. It is of vital importance to understand the mechanisms behind ARG enrichment and its maintenance both on the plant and within the soil microbiome to mitigate the spread of this resistance to animals and humans. Understanding this link between human health, animal health, plant health and the environment is crucial to inform implementation of new regulations and practice regarding antibiotic use in agriculture and manure application, aimed at ensuring the antibiotic resistance crisis is not aggravated.

Extreme Symptom Burden for Patients With COVID-19 at the End of Life; Extrapolation of Knowledge Gained to Achieve Sustained Comfort and Dignity for all Patients in Their Last Days of Life1.

BACKGROUND: We describe two complex cases in the setting of COVID-19 at the End of Life, to enhance learning for all patients. CASE PRESENTATION: Maintenance of sustained comfort in two cases required multiple drugs, specifically selected for symptoms that necessitated three separate pumps delivering continuous 24-hour subcutaneous infusion. CASE MANAGEMENT: Management of sustained comfort included opioid, midazolam, anti-secretory, diclofenac for intractable temperature, phenobarbital for extreme agitation, in one, where seizure activity was present, while insomnia, was a prominent feature of another. Management of Akatasia was also required. CASE OUTCOME: Attention to each individual patient's rapidly evolving symptoms, during the dying phase, with a thorough differential diagnosis, wa s vitally important in the context of a 'Good Death'. This was achieved in both cases, reflected by evidence at the bedside of comfort and a minimum need for 'as required' drugs in the last days of life. CONCLUSIONS: COVID-19 being a new illness, we need to prospectively study the symptom burden/clustering at End of Life and learn from management of this new disease for other illnesses also. Further research is required to develop protocols on; when does Midazolam dose reach tolerance and when should an alternative drug such as phenobarbital for sustained Gamma-Aminobutyric Acid effects be initiated; examine the optimal approach to sustained temperature control; be cognisant of extrapyramidal side effects of drugs used at End of Life and consider looking at a lack of need for 'as required' drugs in the last days of life as an outcome measure of sustained comfort.

Yeast mannan rich fraction positively influences microbiome uniformity, productivity associated taxa, and lay performance.

BACKGROUND: Alternatives to antibiotic as growth promoters in agriculture, such as supplemental prebiotics, are required to maintain healthy and high performing animals without directly contributing to antimicrobial resistance bioburden. While the gut microbiota of broiler hens has been well established and successfully correlated to performance, to our knowledge, a study has yet to be completed on the effect of prebiotic supplementation on correlating the mature laying hen productivity and microbiota. This study focused on establishing the impact of a yeast derived prebiotic, mannan rich fraction (MRF), on the cecal microbiota of late laying hens. This study benefitted from large sample sizes so intra- and intergroup variation effects could be statistically accounted for. RESULTS: Taxonomic richness was significantly greater at all taxonomic ranks and taxonomic evenness was significantly lower for all taxonomic ranks in MRF-supplemented birds (P < 0.005). Use of principal coordinate analyses and principal component analyses found significant variation between treatment groups. When assessed for compositional uniformity (an indicator of flock health), microbiota in MRF-supplemented birds was more uniform than control birds at the species level. From a food safety and animal welfare perspective, Campylobacter jejuni was significantly lower in abundance in MRF-supplemented birds. In this study, species associated with high weight gain (an anticorrelator of performance in laying hens) were significantly lower in abundance in laying hens while health-correlated butyrate and propionate producing species were significantly greater in abundance in MRF-supplemented birds. CONCLUSIONS: The use of prebiotics may be a key factor in controlling the microbiota balance limiting agri-food chain pathogen persistence and in promoting uniformity. In previous studies, increased α- and ß-diversity indices were determinants of pathogen mitigation and performance. MRF-supplemented birds in this study established greater α- and ß-diversity indices in post-peak laying hens, greater compositional uniformity across samples, a lower pathogenic bioburden and a greater abundance of correlators of performance.

Environmental microbiome diversity and stability is a barrier to antimicrobial resistance gene accumulation.

When antimicrobial resistant bacteria (ARB) and genes (ARGs) reach novel habitats, they can become part of the habitat's microbiome in the long term if they are able to overcome the habitat's biotic resilience towards immigration. This process should become more difficult with increasing biodiversity, as exploitable niches in a given habitat are reduced for immigrants when more diverse competitors are present. Consequently, microbial diversity could provide a natural barrier towards antimicrobial resistance by reducing the persistence time of immigrating ARB and ARG. To test this hypothesis, a pan-European sampling campaign was performed for structured forest soil and dynamic riverbed environments of low anthropogenic impact. In soils, higher diversity, evenness and richness were significantly negatively correlated with relative abundance of >85% of ARGs. Furthermore, the number of detected ARGs per sample were inversely correlated with diversity. However, no such effects were present in the more dynamic riverbeds. Hence, microbiome diversity can serve as a barrier towards antimicrobial resistance dissemination in stationary, structured environments, where long-term, diversity-based resilience against immigration can evolve.

Trends in obstetric anal sphincter injury in spontaneous vaginal delivery versus operative vaginal delivery over a 10-year period: Lessons learned.

OBJECTIVE: To evaluate trends in the incidence of women with obstetric anal sphincter injuries (OASIS) over a 10-year period comparing spontaneous vaginal delivery (SVD) and operative vaginal delivery (OVD). METHODS: A retrospective study was performed in which all women who underwent vaginal delivery over a 10-year period (n = 86 242, 2009-2018) at the Rotunda Hospital were reviewed. The overall incidence of OASIS was compared with incidence rates stratified by parity and type of vaginal birth. RESULTS: The 10-year vaginal delivery rate was 69% (n = 59 187) where 24 580 women (42%) were primiparous and 34 607 women (58%) were multiparous. SVD rate was 74% and OVD rate was 26%. The overall incidence of OASIS was 2.9%. The incidence of OASIS in OVD was 5.5% and the incidence in SVD was 2%. Of 498 multipara who sustained OASIS, 366 (73%) had an SVD without episiotomy compared with 14 (3%) who had an episiotomy. There was a significant reduction of OASIS over the 10-year period in primipara who had an OVD but no reduction in the other groups. CONCLUSION: The primiparous OVD group had a significant reduction of OASIS. Continued education around perineal protection and episiotomy at SVD could positively impact further reduction in OASIS, particularly in the SVD groups.

Comparison of soil and grass microbiomes and resistomes reveals grass as a greater antimicrobial resistance reservoir than soil.

Grasslands cover a large proportion of global agricultural landmass used to feed herbivores and ruminants and link the environment to the food chain via animals onto humans. However, most scientific studies of antimicrobial resistance and microbiomes at the environmental - animal nexus have focused on soil or vegetables rather than grasslands. Based on previous microbiome phyllosphere-soil studies we hypothesised that the microbiome and resistomes across soil and grass would have a core of shared taxa and antimicrobial resistance genes (ARGs), but that in addition each would also have a minority of unique signatures. Our data indicated grass contained a wider variety and higher relative abundance of ARGs and mobile genetic elements (MGEs) than soil with or without slurry amendments. The microbiomes of soil and grass were similar in content but varied in the composition proportionality. While there were commonalities across many of the ARGs present in soil and on grass their correlations with MGEs and bacteria differed, suggesting a source other than soil is also relevant for the resistome of grass. The variations in the relative abundances of ARGs in soil and on grass also indicated that either the MGEs or the bacteria carrying the ARGs comprised a higher relative abundance on grass than in soil. We conclude that while soil may be a source of some of these genes it cannot be the source for all ARGs and MGEs. Our data identifies grass as a more diverse and abundant reservoir of ARGs and MGEs in the environment than soil, which is significant to human and animal health when viewed in the context of grazing food animals.

Differential impact of swine, bovine and poultry manure on the microbiome and resistome of agricultural grassland.

Land spreading of animal manure is an essential process in agriculture. Despite the importance of grassland in global food security the potential of the grass phyllosphere as a reservoir of antimicrobial resistance (AMR) is unknown. Additionally, the comparative risk associated with different manure sources is unclear. Due to the One Health nature of AMR there is an urgent need to fully understand the risk associated with AMR at the agriculture - environmental nexus. We performed a grassland field study to assess and compare the relative and temporal impact of bovine, swine and poultry manure application on the grass phyllosphere and soil microbiome and resistome over a period of four months, using 16S rRNA amplicon sequencing and high-throughput quantitative PCR (HT-qPCR). The soil and grass phyllosphere contained a diverse range of antimicrobial resistance genes (ARGs) and mobile genetic elements (MGEs). Manure treatment was found to introduce ARGs belonging to clinically important antimicrobial classes, such as aminoglycoside and sulphonamide into grass and soil. Temporal analysis of ARGs and MGEs associated with manure treatment indicated ARGs patterns were similar across the different manure types in the manure treated soil and grass phyllosphere. Manure treatment resulted in the enrichment in members of the indigenous microbiota and the introduction of manure associated bacteria, with this impact extending past the recommended six-week exclusion period. However, these bacteria were in low relative abundance and manure treatment was not found to significantly impact the overall composition of the microbiome or resistome. This provides evidence that the current guidelines facilitate reduction of biological risk to livestock. Additionally, in soil and grass samples MGEs correlated with ARGs from clinically important antimicrobial classes, indicating the key role MGEs play in horizontal gene transfer in agricultural grassland. These results demonstrate the role of the grass phyllosphere as an under-studied sink of AMR.

Acinetobacter baumannii from grass: novel but non-resistant clones.

Acinetobacter baumannii is one the most worrisome nosocomial pathogens, which has long been considered almost mainly as a hospital-associated bacterium. There have been some studies about animal and environmental isolates over the last decade. However, little effort has been made to determine if this pathogen dwells in the grass. Here, we aim to determine the evolutionary relationships and antibiotic resistance of clones of A. baumannii sampled from grass to the major human international clones and animal clones. Two hundred and forty genomes were considered in total from four different sources for this study. Our core and accessory genomic epidemiology analyses showed that grass isolates cluster in seven groups well differentiated from one another and from the major human and animal isolates. Furthermore, we found new sequence types under both multilocus sequence typing schemes: two under the Pasteur scheme and seven for the Oxford scheme. The grass isolates contained fewer antibiotic-resistance genes and were not resistant to the antibiotics tested. Our results demonstrate that these novel clones appear to have limited antibiotic resistance potential. Given our findings, we propose that genomic epidemiology and surveillance of A. baumannii should go beyond the hospital settings and consider the environment in an explicit One Health approach.

Education and Training Adaptations for Health Workers during the COVID-19 Pandemic: A Scoping Review of Lessons Learned and Innovations.

Introduction: The COVID-19 pandemic has considerably impacted the clinical education and training of health workers globally, causing severe disruptions to learning environments in healthcare facilities and limiting the acquisition of new clinical skills. Consequently, urgent adaptation measures, including simulation training and e-learning, have been implemented to mitigate the adverse effects of clinical education. This scoping review aims to assess the impact of COVID-19 on medical education and training, examine the implemented adaptation measures, and evaluate their effectiveness in improving health workers' education and training during the pandemic. Methods: Employing the PRISMA-ScR framework and Arksey and O'Malley's methodological guidance, we conducted a scoping review, systematically searching PubMed, medRxiv, Google, and DuckDuckGo databases to account for the grey literature. The search included studies published between 1 December 2019 and 13 October 2021, yielding 10,323 results. Of these, 88 studies focused on health worker education and training during the pandemic. Results: Our review incorporated 31,268 participants, including physicians, medical trainees, nurses, paramedics, students, and health educators. Most studies (71/88, 81%) were conducted in high-income and lower-middle-income countries. The pandemic's effects on health workers' clinical skills and abilities have necessitated training period extensions in some cases. We identified several positive outcomes from the implementation of simulation training and e-learning as adaptation strategies, such as enhanced technical and clinical performance, increased confidence and comfort, and an expanded global educational outreach. Conclusions: Despite challenges like insufficient practical experience, limited interpersonal interaction opportunities, and internet connectivity issues, simulation training, e-learning, and virtual training have proven effective in improving clinical education and training during the COVID-19 pandemic. Further research is required to bolster preparedness for future pandemics or similar situations.

First Peoples' knowledge leads scientists to reveal 'fairy circles' and termite linyji are linked in Australia.

In the past, when scientists encountered and studied 'new' environmental phenomena, they rarely considered the existing knowledge of First Peoples (also known as Indigenous or Aboriginal people). The scientific debate over the regularly spaced bare patches (so-called fairy circles) in arid grasslands of Australian deserts is a case in point. Previous researchers used remote sensing, numerical modelling, aerial images and field observations to propose that fairy circles arise from plant self-organization. Here we present Australian Aboriginal art and narratives, and soil excavation data, that suggest these regularly spaced, bare and hard circles in grasslands are pavement nests occupied by Drepanotermes harvester termites. These circles, called linyji (Manyjilyjarra language) or mingkirri (Warlpiri language), have been used by Aboriginal people in their food economies and for other domestic and sacred purposes across generations. Knowledge of the linyji has been encoded in demonstration and oral transmission, ritual art and ceremony and other media. While the exact origins of the bare circles are unclear, being buried in deep time and Jukurrpa, termites need to be incorporated as key players in a larger system of interactions between soil, water and grass. Ecologically transformative feedbacks across millennia of land use and manipulation by Aboriginal people must be accounted for. We argue that the co-production of knowledge can both improve the care and management of those systems and support intergenerational learning within and across diverse cultures.

Influence of soil use on prevalence of tetracycline, streptomycin, and erythromycin resistance and associated resistance genes.

This study examined differences in antibiotic-resistant soil bacteria and the presence and quantity of resistance genes in soils with a range of management histories. We analyzed four soils from agricultural systems that were amended with manure from animals treated with erythromycin and exposed to streptomycin and/or oxytetracycline, as well as non-manure-amended compost and forest soil. Low concentrations of certain antibiotic resistance genes were detected using multiplex quantitative real-time PCR (qPCR), with tet(B), aad(A), and str(A) each present in only one soil and tet(M) and tet(W) detected in all soils. The most frequently detected resistance genes were tet(B), tet(D), tet(O), tet(T), and tet(W) for tetracycline resistance, str(A), str(B), and aac for streptomycin resistance, and erm(C), erm(V), erm(X), msr(A), ole(B), and vga for erythromycin resistance. Transposon genes specific for Tn916, Tn1549, TnB1230, Tn4451, and Tn5397 were detected in soil bacterial isolates. The MIC ranges of isolated bacteria for tetracycline, streptomycin, and erythromycin were 8 to >256 µg/ml, 6 to >1,024 µg/ml, and 0.094 to >256 µg/ml, respectively. Based on 16S rRNA gene similarity, isolated bacteria showed high sequence identity to genera typical of soil communities. Bacteria with the highest MICs were detected in manure-amended soils or soils from agricultural systems with a history of antibiotic use. Non-manure-amended soils yielded larger proportions of antibiotic-resistant bacteria, but these had lower MICs, carried fewer antibiotic resistance genes, and did not display multidrug resistance (MDR).

Global protein responses of multidrug resistance plasmid-containing Escherichia coli to ampicillin, cefotaxime, imipenem and ciprofloxacin.

OBJECTIVES: This study compared the proteomics of Escherichia coli containing the multidrug resistance plasmid pEK499 under antimicrobial stress and with no antimicrobial. METHODS: We utilised mass spectrometry-based proteomics to compare the proteomes of the bacteria and plasmid under antimicrobial stress and no antimicrobial. RESULTS: Our analysis identified statistically significant differentially abundant (SSDA) proteins common to groups exposed to the ß-lactam antimicrobials but not ciprofloxacin, indicating a ß-lactam stress response to exposure from this class of drugs, irrespective of ß-lactam resistance or susceptibility. Data arising from comparisons of the proteomes of ciprofloxacin-treated E. coli and controls detected an increase in the relative abundance of proteins associated with ribosomes, translation, the TCA cycle and several proteins associated with detoxification, and a decrease in the relative abundance of proteins associated with the stress response, including oxidative stress. We identified changes in proteins associated with persister formation in the presence of ciprofloxacin but not the ß-lactams. The plasmid proteome differed across each treatment and did not follow the pattern of antimicrobial-antimicrobial resistance (AMR) protein associations: a relative increase was observed in the amount of CTX-M-15 in the presence of cefotaxime and ciprofloxacin, but not the other ß-lactams, suggesting regulation of CTX-M-15 protein production. CONCLUSION: The proteomic data from this study provided novel insights into the proteins produced from the chromosome and plasmid under different antimicrobial stresses. These data also identified novel proteins not previously associated with AMR or antimicrobial responses in pathogens, which may well represent potential targets of AMR inhibition.