Selective Plating Research Articles

A role for the stringent response in ciprofloxacin resistance in Pseudomonas aeruginosa

Pseudomonas aeruginosa is a major cause of nosocomial infections and the leading cause of chronic lung infections in cystic fibrosis and chronic obstructive pulmonary disease patients. Antibiotic treatment remains challenging because P. aeruginosa is resistant to high concentrations of antibiotics and has a remarkable ability to acquire mutations conferring resistance to multiple groups of antimicrobial agents. Here we report that when P. aeruginosa is plated on ciprofloxacin (cipro) plates, the majority of cipro-resistant (ciproR) colonies observed at and after 48 h of incubation carry mutations in genes related to the Stringent Response (SR). Mutations in one of the major SR components, spoT, were present in approximately 40% of the ciproR isolates. Compared to the wild-type strain, most of these isolates had decreased growth rate, longer lag phase and altered intracellular ppGpp content. Also, 75% of all sequenced mutations were insertions and deletions, with short deletions being the most frequently occurring mutation type. We present evidence that most of the observed mutations are induced on the selective plates in a subpopulation of cells that are not instantly killed by cipro. Our results suggests that the SR may be an important contributor to antibiotic resistance acquisition in P. aeruginosa.

Occurrence and persistence of multidrug-resistant Enterobacterales isolated from urban, industrial and surface water in Monastir, Tunisia

The One Health approach of antimicrobial resistance highlighted the role of the aquatic environment as a reservoir and dissemination source of resistance genes and resistant bacteria, especially due to anthropogenic activities. Resistance to extended-spectrum cephalosporins (ESC) conferred by extended-spectrum beta-lactamases (ESBLs) in E. coli has been proposed as the major marker of the AMR burden in cross-sectoral approaches. In this study, we investigated wastewater, surface water and seawater that are subjected to official water quality monitoring in Monastir, Tunisia. While all but one sample were declared compliant according to the official tests, ESC-resistant bacteria were detected in 31 (19.1 %) samples. Thirty-nine isolates, coming from urban, industrial and surface water in Monastir, were collected and characterized using antibiograms and whole-genome sequencing. These isolates were identified as 27 Escherichia coli (69.3 %) belonging to 13 STs, 10 Klebsiella pneumoniae (25.6 %) belonging to six STs, and two Citrobacter freundii (5.1 %). We observed the persistence and dissemination of clones over time and in different sampling sites, and no typically human-associated pathogens could be identified apart from one ST131. All isolates presented a blaCTX-M gene – blaCTX-M-15 (n = 22) and blaCTX-M-55 (n = 8) being the most frequent variants – which were identified on plasmids (n = 20) or on the chromosome (n = 19). In conclusion, we observed ESC resistance in rather ubiquitous bacteria that are capable of surviving in the water environment. This suggests that including the total coliform count and the ESBL count as determined by bacterial growth on selective plates in the official monitoring would greatly improve water quality control in Tunisia.

Carbapenem-resistant Acinetobacter baumannii carrier detection: a simple and efficient protocol.

Carbapenem-resistant Acinetobacter baumannii (CRAB) is a substantial cause of nosocomial infections, classified among the most significant multidrug-resistant pathogens by the World Health Organization and by the US Centers for Disease Control. Limiting the spread of CRAB is an important goal of infection control, but laboratory methods for identification of CRAB carriers are not standardized. In this work, we compared different selective agar plates, tested the efficiency of A. baumannii identification by PCR for species-specific genes, and used PCR-based detection of common resistance genes to confirm the carbapenem-resistant phenotype. During a prospective study, we also determined the optimal sample enrichment time. Based on our results, we propose a simple and efficient protocol for the detection of CRAB carriage using skin sampling, short enrichment, selection on appropriate agar plates, and PCR-based identification, resulting in a turn-around time of 24 hours.

Membrane filtration for enumeration of Listeria monocytogenes at low levels on salad leaf

The reference method BS EN ISO 11290-2:2017 is insufficiently sensitive to enumerate Listeria monocytogenes in most commercially prepared leaf salads. A more sensitive method for enumerating low levels of Listeria spp. is required to evaluate the impact of process changes and the effect of Listeria control mechanisms in chilled foods including salad leaf. Membrane filtration allows larger volumes of food to be tested but care must be taken to avoid excessive pigmentation of the membranes by damage to leaf during sample preparation and bag homogenisation. Blue-green colonies can be identified after 48 h of incubation of the membranes on Listeria Ottaviani and Agosti selective agar plates, these colonies are indicative of Listeria spp., but halo zones cannot be distinguished. Results obtained by this technique are reported showing enumeration of 5 CFU/g added L. monocytogenes.

Biodiversity of hydrolytic enzymes-producing soil bacteria from a Durian Park, Jombang, Indonesia: Beneficial prospect for sustainable agriculture

Abstract. Ni’matuzahroh, Affandi M, Supriyanto A, Rustantina B, Jaiyah LA, Rahmawati A, Nurhayati H, Sari SK, Khiftiyah AM, Huri D. 2024. Biodiversity of hydrolytic enzymes-producing soil bacteria from a Durian Park, Jombang, Indonesia: Beneficial prospect for sustainable agriculture. Biodiversitas 25: 392-403. Biofertilizer is an alternative to chemical fertilizer that can enhance plant growth but is specific to certain plants and soils. Various biofertilizers have been produced, but the specific biofertilizers to enhance durian growth have not been widely available. This study aims to determine the potential of hydrolytic enzyme-producing bacteria, one of the microbial components of biofertilizers, in the De Durian Park (DDP) area, Wonosalam, Jombang District, Indonesia. The bacteria were isolated using the selective medium plating technique. The obtained isolates were screened for their ability to produce cellulase, amylase, protease, and lipase. The clear zone around the colony indicated the ability of the isolates to produce hydrolytic enzymes, and then the clear zone index was obtained. The best three isolates for each enzyme production were characterized macroscopically, microscopically, and biochemically, then identified using 16S rRNA gene sequence analysis. Fifty-two isolates were successfully obtained from the soil of DDP. The best three cellulolytic bacteria had indices ranging from 1.83 to 2.14, categorized as moderate-strong, identified as Bacillus anthracis, B. pacificus, and B. cereus. The amylolytic bacteria ranged from 1.25 to 1.35, categorized as moderate, and identified as Bacillus anthracis, B. paranthracis, and B. paramycoides. The proteolytic bacteria ranged from 1.33 to 1.50, categorized as moderate, identified as B. pumilus, B. paramycoides, and B. cereus. The lipolytic bacteria ranged from 1.94 to 3.87, categorized as moderate-strong, and were identified as Enterobacter sichuanensis, B. pacificus, and E. asburiae. These cellulolytic, amylolytic, proteolytic, and lipolytic bacteria have the potency as candidates for a biofertilizer formula.

Selective near-infrared laser programming for shape-memory polymer–carbon nanotube composite material 4D printing

Abstract Light stimulation can realise the remote control of the deformation of the specific position of 4D printing structure. Shape-memory polymer–carbon nanotube (CNT) composite materials, with outstanding near-infrared photothermal conversion rate and shape-memory ability, is one type of the most popular light responsive smart materials. However, current studies focused on the photothermal effect and shape-memory applications of light-responsive shape-memory polymer composite (SMPC) sheet structures, and there is no research on the photothermal effect in the depth direction of light-responsive SMPC three-dimensional structures. Here, we prepared a UV curable, mechanically robust, and highly deformable shape-memory polymer (IBBA) as the matrix of light responsive SMPC. CNTs were added as photothermal conversion materials. We explore the photothermal effect of near-infrared laser on the surface and depth of IBBA–CNT composites cube. Shape-memory experiments show that different folded shapes can be obtained by selective near-infrared laser programming. Selective near-infrared laser programming three-dimensional movable type plate shows a programming application in depth direction of three-dimensional light-responsive intelligent structure. This research extends the application of near-infrared laser in 4D printing to the depth direction of intelligent structures, which will bring more complex and interesting 4D printing structures in the future.

Adaptation of a Commercial Qualitative BAX® Real-Time PCR Assay to Quantify Campylobacter spp. in Whole Bird Carcass Rinses.

Poultry is the primary reservoir of Campylobacter, a leading cause of gastroenteritis in the United States. Currently, the selective plating methodology using selective agars, Campy Cefex and Modified Charcoal Cefoperazone Deoxycholate agar, is preferentially used for the quantification of Campylobacter spp. among poultry products. Due to the specific nature of Campylobacter, this methodology is not sensitive, which can lead to skewed detection and quantification results. Therefore, Campylobacter detection and quantification methods are urgently needed. The objective was to develop a shortened enrichment-based quantification method for Campylobacter (CampyQuant™) in post-chill poultry rinsates using the BAX® System Real-Time PCR assay for Campylobacter. The specificity and sensitivity for the detection of C. jejuni, C. coli, and C. lari in pure culture were determined. The BAX® System Real-Time PCR assay consistently detected and identified each species 100% of the time with an enumeration range of 4.00 to 9.00 Log10 CFU/mL. Enrichment time parameters for low-level concentrations (0.00, 1.00, and 2.00 Log10 CFU/mL) of Campylobacter using the BAX® System Real-Time PCR assay were elucidated. It was determined that an enrichment time of 20 h was needed to detect at least 1.00 Log10 CFU/mL of Campylobacter spp. Using the BAX® System Real-Time PCR assay for Campylobacter. As a result, time of detection, detection limits, and enrichment parameters were used to develop the CampyQuant™ linear standard curve using the detected samples from the BAX® System Real-Time PCR assay to quantify the levels in post-chill poultry rinsates. A linear fit equation was generated for each Campylobacter species using the cycle threshold from the BAX® System Real-Time PCR assay to estimate a pre-enrichment of 1.00 to 4.00 Log10 CFU/mL of rinsates detected. The statistical analyses of each equation yielded an R2 of 0.93, 0.76, and 0.94 with a Log10 RMSE of 0.64, 1.09, and 0.81 from C. jejuni, C. coli, and C. lari, respectively. The study suggests that the BAX® System Real-Time PCR assay for Campylobacter is a more rapid, accurate, and efficient alternative method for Campylobacter enumeration.

Low-Cost, Compact Quadrupole Mass Filters with Unity Mass Resolution via Ceramic Resin Vat Photopolymerization.

This study reports novel, compact, and additively manufactured quadrupole mass filters (QMFs) with adequate filtering performance for practical mass spectrometry applications. The QMFs are monolithically fabricated via vat photopolymerization of glass-ceramic resin using 57µm×57µm×100µm voxels, and selective electroless plating of nickel-boron. Experimental characterization of QMF prototypes at 1.74MHz using FC-43 yields 131Da peaks with 0.50Da full width at half maximum (260 resolution), surpassing the resolution of reported miniaturized counterparts under similar conditions, and being on par with commercial, non-miniaturized, heavier devices. The sensitivity of the 3D-printed devices is estimated at 0.13mATorr-1 (comparable to that of optimized, commercial counterparts), while the devices attained up to 250Da of mass range (limited by the driving electronics). The work is of interest to low-cost, capable mass spectrometry, 3D-printed instruments, and in-space manufacturing of complex instrumentation.

Is Brucella excreted in cattle faeces? – Evidence from Punjab, India

Brucellosis is a neglected zoonosis that affects animals and people in much of the underdeveloped world. The disease is endemic in cattle in Punjab, India and controlling it is a public health challenge. Dairy farmers and farm labour commonly handle cattle faeces with bare hands and personal protective equipments are not used. No studies have been conducted about the shedding of Brucella species in faeces of sero positive cattle in the state. This study aimed to isolate and identify the Brucella species from faeces of sero positive cattle in Punjab, India. Faecal samples were collected from 350 Brucella sero positive cattle in Ludhiana district of Punjab, India. Isolation was performed using a pre-enriched Brucella selective broth medium as well as Brucella selective medium agar plates containing horse serum and Brucella selective supplements. Isolates were identified using Gram staining technique and rapid slide agglutination test, and then confirmed by using bcsp31 and 16s rRNA genus specific PCR. Isolates were further identified up to species level by using Bruce-Ladder multiplex PCR. Fourteen Brucella species were isolated, all of which showed coccobacilli on gram staining, positive rapid slide agglutination test and amplification of bcsp31 and 16s rRNA genes. Of the 14 isolates, 11 were identified as Brucella abortus and 3 were identified as Brucella melitensis. The study demonstrates that animal faeces could pose a potential risk for animal and human health and faeces of seropositive cattle must be handled with care.

Performance of Selective Plated Copper Coatings on Stainless Steel 316L and Nickel Alloy Ni201: Microstructure, Microhardness, Wear Resistance, and Corrosion Resistance

This study investigates the properties and performance of selective plated copper coatings on stainless steel 316L and nickel alloy Ni201 substrates, using acidic and alkaline electrolyte solutions. The analysis encompasses surface microstructure, elemental distribution, microhardness, surface roughness, wear resistance, and corrosion resistance of the coatings. The results demonstrate that the selective plated copper coatings exhibit a uniform and continuous deposition, free from visible irregularities or structural imperfections. Notably, the alkaline copper coatings exhibit significantly higher microhardness values compared to the acidic coatings, irrespective of the substrate materials. Surface roughness measurements reveal an increase in roughness after wear testing for all coatings, with the alkaline coatings showing lower initial roughness values and superior wear resistance compared to the acidic coatings. Concerning corrosion resistance, the alkaline copper coatings display a higher susceptibility to corrosion compared to the acidic coatings. Generally, the findings underscore the effectiveness of the selective plating process in producing high-quality, uniform, and defect-free copper coatings on stainless steel and nickel alloy substrates.

Study the Antibacterial Mechanism of Diclofenac and its Activity Alone or Combined with Ciprofloxacin in Treating Urinary Tract Infection

This study aimed to compare the effects of diclofenac, ciprofloxacin and their combination groups on urine tract infection (U.T.I.s) caused by resistance E coli 0157 H7 in vitro and in vivo. Two hundred urine samples were collected from adult women patients suffering from U.T.I.s from February 2022 to July 2022. The urine specimen was cultured on the blood agar and then incubated at 37°C for (1-2) days; MacConkey agar is the media used for determining the biochemistry results, and identification by Rapidchek test which was performed on typical colonies from the selective plate. The M.I.C effect of Diclofenac began at (25600µg/ml) against resistance E coli 0157H7 while M.I.C of ciprofloxacin it was at (0.96mg/ml), but M.I.C of a combination between (diclofenacn+ciprofloxacin) it was at (400+0.48) mg/ml. Resistance induction assay,with the ciprofloxacin has increased four times, while with the diclofenac has doubled, whilst the combination between (diclofenacn+ciprofloxacin) has no changed after 21 days, according to M.I.C.in the time-kill assay, it was proved that the ciprofloxacin and the combination between (diclofenacn+ciprofloxacin) works after 6 hours, compared to the diclofenac, which started to reduce bacterial counting after 40. After that, the examination was carried out by scanning electronic microscope (S.E.M.) to exam the mechanics of diclofenac,work which was found that it was works as anti-biofilm In this study, forty-eighth (48) rabbits were used and divided into six groups as follow positive control (P.C.), negative control (N.C.), diclofenac (D.C.) in 1mg/kg group, ciprofloxacin (C.I.P.)in7mg/kg group, combination (ciprofloxacin 3.5 mg/kg+diclofenac1mg/kg)COM1 group and combination (ciprofloxacin 1.75 mg/kg+diclofenac1mg/kg) com2 All animals (injected with 0.1 ml in CFU E coli 0157 H7 by urinary catheterization route excepting negative control all group excepting negative control resulted in a significant increase in pus cell, epithelium cell concentration in the urine after three days E coli 0157 H7 infection comparison with negative control while in all experimental period after (14 days) showed no significant (P < 0.05) between positive control (P.C.) and diclofenac treated groups but combination COM1 group and com2 decrease significantly (P< 0.05) after (seven and fourteen) days comparison with positive control. diclofenac can be combined with antibiotics as an anti-virulence agent, enhancing the immune system's ability to eradicate infection

Searching for Strep A in the clinical environment during a human challenge trial: a sub-study protocol.

Streptococcus pyogenes (also known as group A Streptococcus , Strep A) is an obligate human pathogen with significant global morbidity and mortality. Transmission is believed to occur primarily between individuals via respiratory droplets, but knowledge about other potential sources of transmission via aerosols or the environment is limited. Such knowledge is required to design optimal interventions to control transmission, particularly in endemic settings. We aim to detail an experimental methodology to assess the transmission potential of Strep A in a clinical environment. We will examine potential sources of transmission in up to 20 participants recruited to the Controlled human infection for penicillin against Streptococcus pyogenes (CHIPS) Trial. Three approaches to understanding transmission will be used: the use of selective agar settle plates to capture possible droplet or airborne spread of Strep A; measurement of the possible distance of Strep A droplet spread during conversation; and environmental swabbing of personal and common high-touch items to detect the presence of Strep A on hard and soft surfaces. All methods are designed to allow for an assessment of transmission potential by symptomatic, asymptomatic and non-cases. Ethical approval has been obtained through Bellberry Human Research Ethics Committee (approval 2021-03-295). Trial registration number: ACTRN12621000751875. Any results elicited from these experiments will be of benefit to the scientific literature in improving our knowledge of opportunities to prevent Strep A transmission as a direct component of the primordial prevention of rheumatic fever. Findings will be reported at local, national and international conferences and in peer-reviewed journals.

Beneficial microbial consortium improves winter rye performance by modulating bacterial communities in the rhizosphere and enhancing plant nutrient acquisition.

The beneficial effect of microbial consortium application on plants is strongly affected by soil conditions, which are influenced by farming practices. The establishment of microbial inoculants in the rhizosphere is a prerequisite for successful plant-microorganism interactions. This study investigated whether a consortium of beneficial microorganisms establishes in the rhizosphere of a winter crop during the vegetation period, including the winter growing season. In addition, we aimed for a better understanding of its effect on plant performance under different farming practices. Winter rye plants grown in a long-time field trial under conventional or organic farming practices were inoculated after plant emergence in autumn with a microbial consortium containing Pseudomonas sp. (RU47), Bacillus atrophaeus (ABi03) and Trichoderma harzianum (OMG16). The density of the microbial inoculants in the rhizosphere and root-associated soil was quantified in autumn and the following spring. Furthermore, the influence of the consortium on plant performance and on the rhizosphere bacterial community assembly was investigated using a multidisciplinary approach. Selective plating showed a high colonization density of individual microorganisms of the consortium in the rhizosphere and root-associated soil of winter rye throughout its early growth cycle. 16S rRNA gene amplicon sequencing showed that the farming practice affected mainly the rhizosphere bacterial communities in autumn and spring. However, the microbial consortium inoculated altered also the bacterial community composition at each sampling time point, especially at the beginning of the new growing season in spring. Inoculation of winter rye with the microbial consortium significantly improved the plant nutrient status and performance especially under organic farming. In summary, the microbial consortium showed sufficient efficacy throughout vegetation dormancy when inoculated in autumn and contributed to better plant performance, indicating the potential of microbe-based solutions in organic farming where nutrient availability is limited.

Laser‐Activated Selective Electroless Plating on 3D Structures via Additive Manufacturing for Customized Electronics

AbstractThis work proposes a facile and economical hybrid additive manufacturing (HAM)technology combining fused deposition modeling (FDM) 3D printing and laser‐activated selective electroless plating (ELP) for fabricating full functional end‐use 3D customized electronics. A functional acrylonitrile butadiene styrene (ABS) filament doped with dicopper hydroxide phosphate (Cu2(OH)PO4) catalysts is developed for FDM 3D printing. The 3D printed structure is selectively laser‐activated to generate CuI plating seeds on the ABS surface and then electrolessly plated. The poor surface finish, especially the layer lines, is an intrinsic defect of extrusion 3D printing, which not only affected the fabrication quality of the 3D substrates but also the electrical performance of the attached circuitry. Herein, a chemical polishing process based on acetone vapor is explored and characterized to significantly improve the surface quality and thereby the electrical performance of the attached copper layer. In this way, highly conductive metallic circuitry can be freeformly deposited and patterned on the 3D structure which is extremely attractive for customized 3D electronics. To show the application potential of this technology, a 3D conformal 555 timer astable oscillator circuit board and a hot‐wire flowmeter are developed as demonstrators.

Development of a Polymicrobial Checkerboard Assay as a Tool for Determining Combinatorial Antibiotic Effectiveness in Polymicrobial Communities.

The checkerboard assay is a well-established tool used to determine the antimicrobial effects of two compounds in combination. Usually, data collected from the checkerboard assay use visible turbidity and optical density as a readout. While helpful in traditional checkerboard assays, these measurements become less useful in a polymicrobial context as they do not enable assessment of the drug effects on the individual members of the community. The methodology described herein allows for the determination of cell viability through selective and differential plating of each individual species in a community while retaining much of the high-throughput nature of a turbidity-based analysis and requiring no specialized equipment. This methodology further improves turbidity-based measurements by providing a distinction between bacteriostatic versus bactericidal concentrations of antibiotics. Herein, we use this method to demonstrate that the clinically used antibiotic combination of ceftazidime and gentamicin works synergistically against Pseudomonas aeruginosa in monoculture but antagonistically in a polymicrobial culture also containing Acinetobacter baumannii, Staphylococcus aureus, and Enterococcus faecalis, highlighting the fundamental importance of this methodology in improving clinical practices. We propose that this method could be implemented in clinical microbiology laboratories with minimal impact on the overall time for diagnosis.

Favourable IOCG and polymetallic environs in Marwar - Khetri, NW Indian Shield imprints from aerogeophysical data analysis

The analysis of aeromagnetic data reveals two significant broad oval-shaped aeromagnetic anomalies oriented in the NE-SW direction, west of Laxmangarh and east of Fatehpur. These significant anomalies identified beneath sand-alluvium-covered areas of Rajasthan's Marwar region are of a low dominance nature. These magnetic signatures are associated with gravity gradients in the regional Bouguer gravity map. Magnetic anomalies and subsurface modeling revealed that the remanence source had a high magnetic susceptibility. The ground gravity profiles across the Laxmangarh anomaly show a high gravity variation of 5 mGal/km. The integration of geochemical distribution patterns, spectrometric elemental concentrations, different ratios, and composite image maps has brought out alteration/shear zones that are favourable for mineralization. The results of selective 2D-profiles, plate modeling, and 3D-inversion modeling of these anomalies reveal that the depth of the causative source varies from 300 to 1000 m. The higher-order magnetic susceptibilities, geochemical dispersion pattern, and spectrometric ratio maps and composite images distinguished hydrothermal alteration zones characterised by potassium enrichment. The results indicate the possibility of concealed source rocks with high magnetic mineral content (magnetite, maghemite, titanomaghemite, pyrrhotite, and franklinite?) and a relatively high density. The geophysical signatures observed around Fatehpur and Laxmangarh, with high magnetic contrast, low dominance, and remanence coupled with high gravity values, as well as hydrothermal alteration zones, appear to have striking similarities with the geophysical and geochemical scenarios of some of Australia's Iron Oxide Copper-Gold (IOCG) prospects in the Gawler, Arunta, Tennant, and Mount Isa regions. Therefore, these anomalous areas may be explored for the possibilities of an IOCG or polymetallic type of mineral.

Supplementation of ginger root extract into broiler chicken diet: effects on growth performance and immunocompetence

Ginger contains bioactive compounds that possess anti-inflammatory and antimicrobial properties. In this study, 432-day-old Ross 708 broiler male chicks were randomly allocated to 6 dietary treatments to investigate the effect of ginger root extract (GRE) on immunocompetence and growth performance to 6 wk of age. Treatment 1 (CON) consisted of chicks fed a corn-soybean meal (SBM), a base diet without GRE. Treatment 2 (MX) chicks were given basal diets containing bacitracin methylene disalicylate (BMD) at 0.055 g/kg. Treatments 3 (GRE-0.375%), 4 (GRE-0.75%), 5 (GRE-1.5%), and 6 (GRE-3%) were fed similar diet to control with GRE supplemented at 0.375%, 0.75%, 1.5%, and 3%, respectively. Moreover, HPLC analysis of GRE was carried out to determine the concentration of bioactive compounds found in GRE. Each treatment consisted of 6 replicate pens with 12 chicks/pen. Bodyweight (BW) and feed conversion ratio (FCR) were recorded. Results show that the concentration of bioactive compounds increased with increasing GRE supplementation. Likewise, dietary GRE supplementation did not have any detrimental effect on growth performance parameters up to 1.5%, as values for BWG was not different from CON and MX; however, 3% GRE had the poorest FCR and a lower BWG as compared to other treatments. On d 27 and d 41, fecal and cecal concentrations of total bacteria count (TBC), Escherichia coli, Lactobacillus spp., and Bifidobacterium spp enumerated using selective plating media showed that GRE supplementation significantly reduced (P < 0.05) the amount of TBC and E. coli but increased the number of beneficial microorganisms such as Lactobacillus spp. and Bifidobacterium spp. On d 20, no significant differences were observed (P > 0.05) among all treatments for antibody titer against Newcastle disease virus and total IgY antibodies; however, on d 27, GRE-0.75% had the highest value for both immune indicators and was not different from MX. Dietary supplementation of GRE up to 1.5% enhanced the immune system and suppressed E. coli while promoting the growth of healthy bacteria, without any detrimental effect on growth performance.

Prevalence of Colonization With Antibiotic-Resistant Organisms in Hospitalized and Community Individuals in Bangladesh, a Phenotypic Analysis: Findings From the Antibiotic Resistance in Communities and Hospitals (ARCH) Study

Abstract Background Low- and middle-income countries bear a disproportionate burden of antimicrobial resistance (AMR) but often lack adequate surveillance to inform mitigation efforts. Colonization can be a useful metric to understand AMR burden. We assessed the colonization prevalence of Enterobacterales with resistance to extended-spectrum cephalosporins, carbapenems, colistin, and methicillin-resistant Staphylococcus aureus among hospital and community dwellers. Methods Between April and October 2019, we conducted a period prevalence study in Dhaka, Bangladesh. We collected stool and nasal specimens from adults in 3 hospitals and from community dwellers within the hospitals’ catchment area. Specimens were plated on selective agar plates. Isolates underwent identification and antibiotic susceptibility testing using Vitek 2. We performed descriptive analysis and determined population prevalence estimates accounting for clustering at the community level. Results The majority of both community and hospital participants were colonized with Enterobacterales with resistance to extended-spectrum cephalosporins (78%; 95% confidence interval [95% CI], 73–83; and 82%; 95% CI, 79–85, respectively). Thirty-seven percent (95% CI, 34–41) of hospitalized patients were colonized with carbapenems compared with 9% (95% CI, 6–13) of community individuals. Colistin colonization prevalence was 11% (95% CI, 8–14) in the community versus 7% (95% CI, 6–10) in the hospital. Methicillin-resistant Staphylococcus aureus colonization was similar in both community and hospital participants (22%; 95% CI, 19–26 vs 21% (95% CI, 18–24). Conclusions The high burden of AMR colonization observed among hospital and community participants may increase the risk for developing AMR infections and facilitating spread of AMR in both the community and hospital.

Study of Inter-Species Social Interactions Among Bacterial Cells Using Computer Vision and Zeta Potential Analysis.

The interplay between the growth patterns of two or more bacterial species in a co-culture system is often overlooked in traditional microbiology. Analysing the behaviour of pathogens as part of a cohort of bacterial species becomes important because when under a high degree of stress or in large populations, bacterial species can develop mutants. However, the factors affecting the course of such social evolution remain unexplored. In this article, we have attempted to systematically study the social interaction in paired and triplet mixed cultures of Escherichia coli, Salmonella enterica serovar Typhimurium and Staphylococcus aureus. The method is based on computer vision analysis of selective agar plating of both pure and mixed cultures (plated after co-incubation) followed by Zeta potential measurements. Primarily, the social interactions between bacterial species, whether synergetic or antagonistic, are mediated through the exchange of electrical charges. The density of charges which are present on the bacterial surface can be characterised by measuring the Zeta potential. Studying the Zeta potential of co-cultures in various volume ratios aims at probing the effect of mixing of species on the resultant surface charge of the cells in the cohort. Based on the results, we explore how certain species electrically dominate over others in co-cultures, yet they co-exist. Most importantly, the surface charge modifications arising due to the social interactions can severely affect the bactericidal action of antimicrobial agents. To confirm this, the last section of the manuscript is dedicated to the antimicrobial susceptibility tests performed using the disc diffusion method on pure samples and consortia. The results are presented for eleven different antibiotics indicating significant alterations in the efficacy of some of the antimicrobial agents when used against co-cultures.

Colonization of Residents and Staff of an Italian Long-Term Care Facility and an Adjacent Acute Care Hospital Geriatrics Unit by Multidrug-Resistant Bacteria.

In 2022, we undertook a point prevalence screening study for Enterobacterales with extended-spectrum β-lactamases (ESBLs), high-level AmpC cephalosporinases and carbapenemases, and also methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE) in a long-term care facility (LTCF) and the associated acute-care hospital Geriatrics unit in Bolzano, Northern Italy. Urine samples and rectal, inguinal, oropharyngeal, and nasal swabs were plated on selective agar plates. Metadata of the patients, including demographic data, were collected, and risk factors for colonization were determined. ESBL, AmpC, carbapenemase, and quinolone resistance genes were investigated by the HybriSpot 12 PCR AUTO System. The following colonization percentages by multidrug-resistant (MDR) bacteria have been found in LTCF residents: all MDR organisms, 59.5%; ESBL producers, 46.0% (mainly CTX-M-type enzymes); carbapenemase producers, 1.1% (one Klebsiella pneumoniae with KPC-type); MRSA, 4.5%; VRE, 6.7%. Colonization by MDR bacteria was 18.9% for LTCF staff and 45.0% for Geriatrics unit patients. Peripheral vascular disease, the presence of any medical device, cancer, and a Katz Index of 0 were significant risk factors for colonization of LTCF residents by MDR bacteria in univariate and/or multivariate regression analysis. To conclude, the ongoing widespread diffusion of MDR bacteria in the LTCF suggests that efforts should be strengthened on MDR screening, implementation of infection control strategies, and antibiotic stewardship programs targeting the unique aspects of LTCFs. ClinicalTrials.gov ID: 0530250-BZ Reg01 30/08/2022.