Frequency Of Isolation Research Articles

Fruit Anthracnose on Cavendish bananas Caused by Colletotrichum fructicola in Guangxi, China.

Cavendish banana (Musa spp. AAA group) is one of the main fruit crops worldwide. It is widely planted in Guangdong, Hainan, Guangxi, Fujian and Yunnan provinces in southern China. In November 2020, banana fruits with anthracnose symptoms were collected from Dayu Town (N 23.17°, E 109.80°), Guigang City, and Chengjun Town (N 22.60°, E 110.00°), Yulin City, Guangxi Province, China, where the disease was found on about 70% of the banana plants, and on individual fruit, up to 10% of the surface was covered with symptoms. The symptoms initially began with rust-colored spots on the surface of the immature fruit, which gradually became sunken and cracked as the disease progressed. Small tissues (5×5 mm) from the pericarp at the junction of disease and health were surface-disinfected in 75% ethanol for 10 s, 2% sodium hypochlorite (NaClO) for 1 min, and washed three times in sterile water. Tissue pieces were placed on potato dextrose ager (PDA) and incubated at 25°C. Fifty-nine morphologically similar colonies were obtained after 5 days of incubation, with 100% isolation frequency. Of 59 isolates, GG1-3 isolated from Guigang City and YL4-2 isolated from Yulin City were selected as representative strains for intensive study. Mycelia were off-white for both isolates and conidia obtained from PDA were cylindrical, unicellular, hyaline and obtuse ends, with sizes of 11.5 ± 1.8×3.9 ± 0.8 µm (n=60) and 11.5 ± 1.6×4.1 ± 0.6 µm (n=60) for GG1-3 and YL4-2, respectively (Prihastuti et al. 2009). Genomic DNA was extracted from 7-day-old aerial mycelia using a DNAsecure Plant Kit (Tiangen Biotech, China). The internal transcribed spacer (ITS), the intergenic region of apn2 and MAT1-2-1 (ApMAT) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) were amplified and sequenced (White et al. 1990; Silva et al.2012; Templeton et al. 1992). Sequences were deposited in GenBank (ITS, OR596961 to OR596962; GAPDH, OR661771 to OR661772; APMAT, OR661773 to OR661774) and showed 100% identities with the corresponding type strains sequences of C. fructicola. Phylogenetic tree was constructed with software raxmlGUI v.2.0.0 based on sequences of multiple loci (ITS, GAPDH and ApMAT) and Maximum Likelihood method. Phylogenetic analysis revealed that the two isolates and C. fructicola were clustered in the same clade, with 94% bootstrap support. According to morphology and phylogenetic analysis, the two isolates GG1-3 and YL4-2 were identified as C. fructicola. For pathogenicity tests, healthy fruits were surface sterilized with 75% ethanol followed by a wash with sterilized water. Five adjacent needle punctures in a 5-mm-diameter circle were made with a sterilized needle on healthy fruits, followed by inoculation with 20 μL of conidial suspension (106 spores/ml), and sterilized water was used as controls. All banana fruit were incubated in a humid chamber at 28°C. After 4 days, all inoculated fruits showed visible symptoms and had rust-colored spots on the margins, while control banana fruits remained symptomless. The fungus was isolated from the inoculated fruit and the isolates were found to match the morphological and molecular characteristics of the original isolates, confirming Koch's hypothesis. To our knowledge, this is the first report of fruit anthracnose on Cavendish bananas caused by C. fructicola in China. This study will provide valuable information for prevention and management of anthracnose on banana fruit.

Improving Sound Insulation in Low Frequencies by a Three-Component Cladding Acoustic Metamaterial Panel

In this paper, a three-component cladding acoustic metamaterial panel with good sound insulation effect in the low-frequency range is proposed. The sound transmission loss of metamaterial panels under different structural configurations and different material parameters is investigated by combining finite element simulation calculations with experimental research. The results show that the closer the center of gravity of the scatterer is to the substrate, the better the stability of the resonance unit, the wider the range of effective sound isolation frequencies, and the higher the degree of normalization. The filling rate of the scatterer is maintained at about 0.5 to obtain a better sound insulation effect. At the same time, choosing lower density materials for the substrate and metal materials with high density and high modulus of elasticity for the scatterer can maximally widen the bandgap and allows for low-frequency sound insulation below 600 Hz. This approach improves the low-frequency sound insulation efficiency of acoustic metamaterials. The results provide important explanations and references for a deeper understanding of the sound insulation mechanism and the effects of different parameters on sound insulation.

First report of leaf spot disease caused by Neopestalotiopsis rosae on Lonicera caerulea L. in Heilongjiang Province, China.

Recently, interest in cultivating blue honeysuckle (Lonicera caerulea L.) for horticulture and medicinal uses has grown (Sharma and Lee 2021). Between September 2022 and September 2023, a leaf spot disease (Fig. S1) was observed on approximately 20% of 'Lanjingling' blue honeysuckles grown in a 0.18 ha field in Qiqihar city (123.43°E, 47.92°N), Heilongjiang Province, China. Infected plants displayed black leaf spots that expanded to cover the entire leaf. Small, 3 to 4 mm segments of infected tissue were surface sterilized with 75% ethanol for 30 s and 5% sodium hypochlorite (NaOCl) for 3 min, rinsed three times with sterile distilled water, dried on paper towels, and plated in 9 cm Petri dishes containing potato dextrose agar (PDA) (Ma et al. 2023). To induce sporulation, nine purified cultures (Fig. S2) with similar culture characteristics were finally obtained from ten infected plants and they displayed a conidia morphology consistent with Neopestalotiopsis spp., no other fungi were isolated, and the isolation frequency was 90%. Conidiomata (Fig. S3) were brown to black and distributed in concentric rings with an average size of 261.98 (60.30-451.80) μm (n = 50). The conidia (Fig. S3) were fusoid and had four septa, straight to slightly curved, with an average size of 23.48 (13.50-30.30) × 5.42 (4.50-9.30) μm(n = 50), while basal and apical cells were hyaline and the three middle cells were brown with darker septa. PCR amplification was performed with ITS1/ITS4 (White et al. 1990), EFl-728F/EF1-986R (Carbone and Kohn 1999), and Btub2Fd/Btub4Rd (Glass and Donaldson 1995) primers from the genomic DNA of the LD-330. Sequences of ITS (PP033584), TEF (PP048757), and TUB (PP048758) revealed 99 to 100% (499/500, 255/255, and 481/486) shared identity with Neopestalotiopsis rosae sequences (NR145243, KM199524, and KM199430) (Rebollar-Alviter et al. 2020). Therefore, based on morphological characteristics and molecular phylogeny, LD-330 was identified as N. rosae. Six two-year-old healthy plants of the 'Lanjingling' cultivar were selected for a pathogenicity test (Yan et al. 2023). The leaves were surface disinfected with 75% alcohol and then wiped with sterilized water three times. Three plants were inoculated with 10 ml of LD-330 conidial suspension (1 × 106 spores/ml) or with sterile water as an experimental control, respectively. All plants were in closed plastic bag, incubated in a greenhouse at 28 ℃ and 75% relative humidity (RH) under a 12-h light/dark cycle, and each experiment was performed three times (Rebollar-Alviter et al. 2020). Typical leaf spot symptoms were observed on inoculated leaves after 14 days (Fig. S4), whereas no symptoms were detected on water-treated leaves. The same pathogen was reisolated from infected leaves, displayed the same morphological and molecular traits, and was again identified as N. rosae, confirming Koch's postulate. Neopestalotiopsis rosae was previously reported on pecan (Gao et al. 2022), causing black leaf spot disease in China. To our knowledge, this is the first report of a blue honeysuckle leaf spot caused by N. rosae in China and specifically in the Heilongjiang province which has the largest blue honeysuckle cultivation area in the country. Future research should be directed toward developing comprehensive management measures.

Pressure-guided evaluation of pulmonary vein occlusion during cryoballoon pulmonary vein isolation for atrial fibrillation compared to contrast-guided approach

Abstract Introduction Single-shot ablation devices (e.g. cryoballoon [CB] technique) have simplified pulmonary vein isolation (PVI) for interventional treatment of atrial fibrillation (AF). Vein occlusion is mainly assessed utilizing contrast media (CM) during CB ablation. However, this approach entails possible risks, including renal impairment and adverse contrast-related allergic reactions. Furthermore, the assessment of pulmonary venography is often challenging and necessitates fluoroscopy exposure. Purpose The primary objective of this study is to compare procedural data and outcome of pressure-guided (PG) vs. conventional (CM) assessment of vein occlusion. Methods and results From 07/2018 to 12/2022, 915 patients with AF (59% paroxysmal) undergoing CB-PVI at our hospital were prospectively enrolled (single-center experience). 369 (40,3%) patients (age 64,5 ± 10 years; 154 females 41,7%) underwent PVI with the use of CM (CM group), while in 546 (59,7%) cases (age 65,3 ± 10 years; 222 females 40,6%) pressure curve assessment (PG group) was exclusively used to guide the procedure (and no contrast was given). Compared with the CM approach, pressure-guided procedures had lower X-ray time (9,5±5min vs 6,4±3,5min, P<0,0001) and X-ray dose (586±546cGy/cm2 vs 96,7±93 cGy/cm2, P<0,0001). Procedure time (PG: 90,3±20,1min, CM: 92,7±22,7 min, p:0,1 ) and ablation time (PG: 1352 ± 365 min, CM: 1393 ± 651 min, p: 0,2) were not different between groups. There was no significant difference observed in the BMI between the two groups, with a mean value of ca. 28.2 ± 4 kg/m2. In 79 redo-procedures, persistent isolation of all pulmonary veins was observed in 11/45 (25%) patients in the CM group and 21/34 (61%) patients in the PG group (p: 0.001). Conclusion Compared to current (CM) assessment of vein occlusion, pressure monitoring is associated with less X-ray exposure during the index procedure and more frequent durable isolation of all PVs during repeat study for recurrence.

Fusarium pseudograminearum biomass and toxin accumulation in wheat tissues with and without Fusarium crown rot symptoms.

Fusarium crown rot (FCR) is an important and devastating disease of wheat (Triticum aestivum) caused by the fungus Fusarium pseudograminearum and related pathogens. Using two distinct susceptible cultivars, we investigated the isolation frequencies of F. pseudograminearum and quantified its biomass accumulation and the levels of the associated toxins deoxynivalenol (DON) and DON-3-glucoside (D3G) in inoculated field-grown wheat plants. We detected F. pseudograminearum in stem, peduncle, rachis, and husk tissues, but not in grains, whereas DON and D3G accumulated in stem, rachis, husk, and grain tissues. Disease severity was positively correlated with the frequency of pathogen isolation, F. pseudograminearum biomass, and mycotoxin levels. The amount of F. pseudograminearum biomass and mycotoxin contents in asymptomatic tissue of diseased plants were associated with the distance of the tissue from the diseased internode and the disease severity of the plant. Thus, apparently healthy tissue may harbor F. pseudograminearum and contain associated mycotoxins. This research helps clarify the relationship between F. pseudograminearum occurrence, F. pseudograminearum biomass, and mycotoxin accumulation in tissues of susceptible wheat cultivars with or without disease symptoms, providing information that can lead to more effective control measures.

Dual-function of energy harvesting and vibration isolation via quasi-zero stiffness piezoelectric mechanism

Industry 4.0 realizes intelligent interconnection through the sensor group of the Internet of Things. A key challenge is to achieve the self-powering of sensors and stable operation of precision instruments. This paper introduces a dual-functional structure (VIPEH) integrating energy harvesting (EH) and vibration isolation (VI) based on the quasi-zero stiffness (QZS) piezoelectric mechanism. The paper analyzes the nonlinear statics of piezoelectric flexible beams under large deformations and conducts parametric analysis. A nonlinear dynamic model with electromechanical coupling was developed to investigate the impact of mechanical and electrical parameters on the system's dynamic bifurcation behavior, EH, and VI performance. Finally, an experimental setup is created to evaluate the VIPEH's characteristics. Sweep frequency excitation experiments demonstrate that the initial isolation frequency of VIPEH is lower than 1.4 Hz. The important thing is that VIPEH can still power the sensor based on the isolation frequency, and the output power of a single piezoelectric material can reach 3.19 mW. This not only enables the isolation of low-frequency vibrations but also presents a highly promising application for achieving self-powering in sensor clusters within the context of Industry 4.0 and the IoTs.

High frequency of multidrug-resistant Escherichia coli from cattle in the Cerrado and Pantanal biomes of Brazil

The indiscriminate use of antimicrobials has led to the emergence of resistant bacteria, especially pathogenic strains of Escherichia coli, which are associated with diseases in animals and humans. The aim of the present study was to characterize E. coli isolates in calves with regards to the presence of virulence genes and investigate the resistance of the isolates to different antimicrobials. Between 2021 and 2023, 456 fecal samples were collected from calves in the Pantanal and Cerrado biomes of the state of Mato Grosso do Sul, Brazil. All samples were subjected to microbiological analysis and disc diffusion antibiogram testing. The polymerase chain reaction method was used to detect virulence genes. Bacterial growth was found in 451 of the 456 samples and biochemically identified as Escherichia coli. All 451 isolates (100 %) exhibited some phenotypic resistance to antimicrobials and 67.62 % exhibited multidrug resistance. The frequency of multidrug-resistant isolates in the Cerrado biome was significantly higher than that in the Pantanal biome (p = 0.0001). In the Cerrado, the most common pathotype was Shiga toxin-producing Escherichia coli (STEC) (28 %), followed by toxigenic Escherichia coli (ETEC) (11 %), enterohemorrhagic Escherichia coli (EHEC) (8 %) and enteropathogenic Escherichia coli (EPEC) (2 %). In most cases, the concomitant occurrence of pathotypes was more common, the most frequent of which were ETEC + STEC (33 %), ETEC + EHEC (15 %) and ETEC + EPEC (3 %). The STEC pathotype (30 %) was also found more frequently in the Pantanal, followed by EHEC (12 %), ETEC (9 %) and EPEC (6 %). The STEC pathotype had a significantly higher frequency of multidrug resistance (p = 0.0486) compared to the other pathotypes identified. The frequency of resistance was lower in strains from the Pantanal biome compared to those from the Cerrado biome. Although some factors are discussed in this paper, it is necessary to clarify the reasons for this difference and the possible impacts of these findings on both animal and human health in the region.

Dynamic analysis and performance evaluation of inerter fractional nonlinear quasi-zero stiffness isolator on a multi-span bridge under moving load

In this paper we propose a new vibration isolator system, which combines the advantages of a quasi-zero stiffness (QZS) isolator, a damper exhibiting fractional properties and an inerter, to reduce the vibrations of a multi-span continuous beam bridge excited by moving loads. The inerter produces a fictitious mass amplification effect to improve the controller performance and the fractional order takes into account the previous state of the viscoelastic material. After formulating the dynamics equation using beam theory, the amplitude response is determined analytically using the averaging method. The results obtained from the analytical study are validated using the direct numerical simulation method (Newton–Leipnik method). By comparing the isolation performance of the FQZS (fractional quasi-zero stiffness) isolator and the IFQZS (inerter fractional quasi-zero stiffness) isolator, it is shown that the addition of inertance can significantly suppress the tendency of the curve to slope to the right, allowing us to have a wider isolation frequency range on force transmissibility while improving the efficiency of the isolator. One also shows that increasing the fractional parameter contributes to a decrease in the vibration amplitude of the structure, the amplitude of the force transmitted and the area in which unstable solutions appear. However, beyond a certain value of the fractional parameter, we observe an increase in the latter. In order to further extend the study, bifurcation diagram, phase portrait, time history and power spectral density are explored.

Reducing vibration isolation frequency in an X-shaped two-stage nonlinear system

Reducing vibration isolation frequency in an X-shaped two-stage nonlinear system

Microbiological findings in infective endocarditis, event predictor and prognostic value

Abstract Funding Acknowledgements None. Introduction In infective endocarditis, microbial isolation can be related to the prognosis of the disease. Identify the cause of endocarditis can help decide further management appropriate. Our purpose was to evaluate the most frequent microbiological findings in our healthcare area, as well as their association with prognostic determinants. Material and Methods Retrospective, observational, single-center study*. Based on a registry of patients diagnosed with infective endocarditis during the years 2016-2022 in a reference hospital with cardiac surgery. Patients with infective endocarditis were analyzed according to their type of microbial isolation, observing the microbial epidemiology and comparing these groups according to their baseline characteristics (age, sex, risk factors), the different therapeutic management in each group (type of antibiotic treatment used, surgical intervention, surgical indication etc.) and compared the groups according to the frequency of different prognostic determinants and events (Reinfection, Embolism, Shock, Mortality, local complications, etc.). To analyze the differences in events between different groups of microorganisms, the Chi square statistic of Homogeneity was used, and a significance level of p<0.05 was established. Results 162 patients were analyzed for an average of 66 years. The rate of positive blood cultures was 93%. The most frequently isolated microorganisms were, Figure 1. Patients who suffered from S. aureus endocarditis (with a mean age also of 66±10 years) had a higher prevalence of pacemaker infections and were complicated by septic shock more frequently (43%, p<0.01) than patients with other types of microorganism isolation. However, we did not have high surgery rates, and we did not observe significant differences in terms of recurrence or mortality, despite being a very virulent microorganism. On the other hand, S.Epidermidis (which is associated with early prosthetic valve endocarditis) is the microorganism most closely related with abscesses, fistulas or other perivalvular involvements (34%, p=0.04), in relation to endocarditis after valve surgery. This group also appears to have a greater tendency, although not significant, to cause AV blocks. Furthermore, S.Epidermidis was the group of patients that most frequently underwent surgery (62% p<0.001) Figure 2. Conclusions In this study, we have observed a higher frequency of isolation of E. feacalis, with significant differences in comparison to other series, and a significantly higher number of recurrences in comparison to other microorganisms. S. aureus is the microorganism most linked to shock, but it is also the one with the lowest number of undergone surgeries, despite being comparable populations. In valve prosthetic endocarditis, S. epidermidis was the most frequent pathogen isolated, and was more frequently associated with perivalvular involvement and the need for surgery.

Origami-inspire quasi-zero stiffness structure for flexible low-frequency vibration isolation

As an emerging technology, origami exhibits rich nonlinear static and dynamic properties. However, simulating creases remains a key challenge hindering practice application, especially for volumetric (deformable) origami. Inspired by the bistable behavior and axial-rotational coupling mechanism of triangulated cylindrical origami (TCO), this paper proposes a novel combined truss-spring structure with additional inertial mechanism (TCTS-RIM) for low-frequency vibration isolation. Unlike pure TCO, the TCTS-RIM uses elastic linkages to simulate all creases and modifies crease positions, enhancing physical realization in engineering applications and offering tunable stiffness and inertia on demand. Static analysis shows the modified truss-spring structure in TCTS-RIM has superior quasi-linear negative stiffness compared to pure TCO, which enables a very wide quasi-zero stiffness (QZS) range via linear spring compensation. The wide QZS range for different loads can be realized by setting appropriate structural parameters. From system dynamic equations, nonlinear inertia, nonlinear quadratic force, and nonlinear damping due to RIM are identified and discussed. The Alternating frequency–time harmonic balance method is used to obtain the displacement transmissibility, and its parametric influencing investigations verify that the proposed TCTS-RIM has excellent low-frequency vibration isolation performance and rich tunability. Comparative discussions show the wide QZS range significantly reduces the resonance frequency, broadens the isolation frequency band, and yields superior dynamic performance versus pure TCO isolators. Moreover, equivalent mass, anti-resonance and softening behavior induced by the rotational inertia mechanism further enhance low-frequency vibration isolation performance. An experimental prototype is built, and experimental results validate the correctness of the theoretical analyses. This work presents a simple mechanical implementation of volumetric origami, which may progress the engineering applications of origami and provide a viable approach to low-frequency vibration control.

Microbiological Profile and Susceptibility Pattern of Bacterial Blood Culture Isolates in COVID-19 Patients with Septicemia from a Designated COVID Hospital in Pune

In severe Coronavirus disease 2019 (COVID-19), bloodstream infections (BSIs) are an increasing cause of morbidity and mortality. In critically ill patients with COVID-19, we aimed to evaluate the prevalence, clinical profiles, and outcomes of BSIs. This single-center prospective investigation was conducted at a tertiary care hospital in Western India. All patients (>18 years of age) hospitalized in the intensive care unit (ICU) or ward with RT-PCR-confirmed COVID-19 were included. Demographic information, clinical proficiency, and antibiotic resistance patterns were assessed. Of the 550 patients admitted to the COVID ICU, subsequent BSIs occurred in 7.45% of patients. Gram-negative pathogens comprised a significant proportion of BSIs (53/73, 72.6%). The most frequent isolates were Klebsiella pneumoniae (22/73, 30.1%), Acinetobacter baumannii (11/73,15.06%), and Escherichia coli (7/23, 9.58%). In 57.8% of the cases, multidrug-resistant organisms (MDRO) were discovered. The Enterococcus and K. pneumoniae families comprise the majority of MDRO. Gram-negative bacteria (30.18% [16/53]) were resistant to carbapenems. Increased total leukocyte count, mechanical ventilation, and the presence of comorbidities were significantly associated with the incidence of BSIs. In COVID-19-linked BSIs, we discovered a high frequency of A. baumannii. Clinicians should be aware of potential BSIs in the presence of comorbidities, elevated leukocyte count, and mechanical ventilation. To improve the results, empirical antibiotics must be started promptly, and the situation must be de-escalated quickly. The most frequent isolates were A. baumannii and K. pneumoniae ([11/73, 15.06%] and [22/73, 30.1%], respectively). To reduce the incidence of MDRO, infection control procedures should be strictly followed in patients with multidrug resistance.

BACTERIOLOGICAL ANALYSIS OF URINARY TRACT INFECTIONS AT HYDERABAD, SINDH

Urinary Tract Infections (UTI) is a condition in which micro-organisms multiply within the tract to establish infection. The aim of this study was to assess bacteriological profiling of UTI in Hyderabad, Pakistan. Isolation and identification of bacterial uropathogens were carried out using standard microbiological methods such as microscopic analysis, cultural characteristics, and biochemical testing. A total of 320 urine samples were investigated for bacteriological analysis. Among them, 116 (36.26%) urine samples yielded bacterial growth, which included 74 (23.12%) female and 42 (13.13%) male patients. Bacterial distribution revealed that the most frequent isolate was Escherichia. coli which accounted 60.34% (n=70) of the isolates followed by Klebsiella pneumoniae 13.79% (n=16), Pseudomonas aeruginosa 7.76% (n=9), Enterococcus spp. 7.76% (n=9), Streptococcus spp. 4.31% (n=5), Staphylococcus aureus 3.4% (n=4), Proteus mirabilis 2.59% (n=3). It is concluded that the, bacteriological profiling of urine samples revealed seven different uropathogens circulating in Hyderabad with high prevalence of E. coli.

Frequency of carbapenem resistant providencia stuartii isolation from clinical samples in relation to colistin consumption in the ICU of a tertiary hospital before and during the pandemic (2019–2022)

Frequency of carbapenem resistant providencia stuartii isolation from clinical samples in relation to colistin consumption in the ICU of a tertiary hospital before and during the pandemic (2019–2022)

Antimicrobial susceptibility and resistome of Actinobacillus pleuropneumoniae in Taiwan: a next-generation sequencing analysis

Actinobacillus pleuropneumoniae infection causes a high mortality rate in porcine animals. Antimicrobial resistance poses global threats to public health. The current study aimed to determine the antimicrobial susceptibilities and probe the resistome of A. pleuropneumoniae in Taiwan. Herein, 133 isolates were retrospectively collected; upon initial screening, 38 samples were subjected to next-generation sequencing (NGS). Over the period 2017–2022, the lowest frequencies of resistant isolates were found for ceftiofur, cephalexin, cephalothin, and enrofloxacin, while the highest frequencies of resistant isolates were found for oxytetracycline, streptomycin, doxycycline, ampicillin, amoxicillin, kanamycin, and florfenicol. Furthermore, most isolates (71.4%) showed multiple drug resistance. NGS-based resistome analysis revealed aminoglycoside- and tetracycline-related genes at the highest prevalence, followed by genes related to beta-lactam, sulfamethoxazole, florphenicol, and macrolide. A plasmid replicon (repUS47) and insertion sequences (IS10R and ISVAp11) were identified in resistant isolates. Notably, the multiple resistance roles of the insertion sequence IS10R were widely proposed in human medicine; however, this is the first time IS10R has been reported in veterinary medicine. Concordance analysis revealed a high consistency of phenotypic and genotypic susceptibility to florphenicol, tilmicosin, doxycycline, and oxytetracycline. The current study reports the antimicrobial characterization of A. pleuropneumoniae for the first time in Taiwan using NGS.

Characteristics of antibiotic sensitivity of Acinetobacter baumannii bv. tryptophandestruens and Acinetobacter baumannii clinical isolates

The aim of the study was to determine the sensitivity of the bacteria of the biovar Acinetobacter baumannii bv. tryptophandestruens to antibiotics used to treat Acinetobacter-infection. The object of the study was 86 primary clinical isolates of A. baumannii, of which 34 strains of A. baumannii bv. tryptophandestruens isolated in the microbiological laboratory of the Military Medical Academy in 2021–2022. Species identification of bacteria was carried out by MALDI-ToF mass spectrometry. The biovar tryptophandestruens of A. baumannii was determined on a dense chromogenic medium. The sensitivity of A. baumannii isolates to antibiotics was determined by a “Vitek 2 compact” microbiological analyzer (bioMerieux, France). Clinical categories of isolates sensitivity to antibiotics (S) were identified based on the boundary values of minimum suppressive concentrations (MSC, mg/L) established by the European Committee for the Determination of Sensitivity to Antimicrobial Preparates (EUCAST), version 11.0. Isolates of A. baumannii bv. tryptophandestruens and groups of isolates of other A. baumannii very rarely sensitive to meropenem (8.8±4.6%; 3.8±2.6%, respectively, p 0.05), ciprofloxacin (5.8±4.0; 9.6±4.1%, p 0.05). Strains sensitive to gentamicin are rarely represented in both groups (26.7±7.55; 19.3±5.5%, p 0.05) trimethoprim/sulfamethoxazole (38.8±8.3%; 23.6±5.3%, p 0.05). Sensitivity to polymyxin B was preserved in all strains of both groups (100%). Strains of the tryptophandestruens biovar A. baumannii group surpass strains of the other strain of A. baumannii group in the frequency of isolates with MSC50% tigecycline (MSC50% — 0.5 mg/l; MSC50% — 2 mg/l, respectively), and also have significantly more strains with MSC 0.5 mg/l (52.9% and 15.4%, respectively, p 0.01 ). Thus, the clinical isolates of the biovar A. baumannii bv. tryptophandestruens have no significant differences with isolates of other strains of A. baumannii in the frequency of strains sensitive (S) to meropenem, ciprofloxacin, gentamicin, trimethoprim/sulfamethoxazole, polymyxin B, but they differ in terms of sensitivity to tigecycline — a higher frequency of strains with an MSC of 0.5 mg/l (p 0.01) and an MSC of 50%.

Antibiotic resistance of microorganisms isolated from the urine of patients before surgical treatment for benign prostatic hyperplasia: results from a 7-year single-center study

Introduction. The tendency of microorganisms to develop resistance mechanisms is a widely discussed and significant problem worldwide. Studying regional differences in the qualitative characteristics of microorganisms provides valuable information for empirically preventing and treating infectious complications, as well as providing an enhanced understanding of the variability in microbial community properties within the clinical context of diseases and patients' comorbidity status.Objective. To assess the antibiotic resistance of microorganisms isolated in high titers from the urine samples of patients with benign prostate hyperplasia (BPH) prior to surgery.Materials & Methods. This single-center, retrospective study conducted from March 2016 to February 2023 included 59 suprapubic-draining BPH-patients (Group I), 46 drainage-free BPH-patients with leukocyturia (Group II), and 44 drainage-free BPH-patients and no leukocyturia (Group III). Inclusion criteria: indications for BPH surgery, no history of sexually transmitted diseases, no symptoms of urinary tract infection, and no prostate cancer. The patient's voluntary informed consents to participate were also obtained.Results. The rates of resistance to ciprofloxacin in patients of Group I were statistically significantly higher compared to Group II (85.7% vs 55.6%, p = 0.002). Resistance of gram-negative microorganisms to meropenem and imipenem was higher in Group III compared to Group I (31.1% vs 13.7%, p = 0.006 for meropenem and 44.5% vs 9.8%, p = 0.001 for imipenem, respectively). Resistance of Gram-positive microorganisms to ampicillin in Groups I to III was 13.6%,6.3% and 20.0%, respectively with no significant difference between groups (p > 0.05). However, there was extremely high resistance among verified Gram-positive organisms to all the drugs in the fluoroquinolone class (ciprofloxacin, norfloxacin, levofloxacin) ranged from 63.6% to 80.0%.Conclusion. The present study demonstrates that the isolation frequency of antibiotic-resistant microorganisms from the urine sample of drainage-free BPH-patients or no clinical and laboratory signs of inflammation in the urinary tract is high. The presence of antibiotic resistance provides risks for developing difficult-to-control infectious complications. Currently, assessment of urine-derived microbial antibiotic resistance should be considered in every BPH-patient with indications for surgical management of bladder outlet obstruction, regardless of the presence of risk factors.

The frequency of bacterial isolation of <i>Clostridium</i> spp. and their associations in various forms of clostridiosis in cattle

The article presents the results of isolation of Clostridium spp. bacteria and their associations from cattle with different clinical forms of clostridiosis. From 2016 to 2023, 910 samples of biomaterial collected from cows, heifers and calves under 6 months of age, as well as from stillborn calves and aborted fetuses in case of reproductive pathologies in cows were investigated by bacteriological methods. The following species play a major role in the etiology of bovine clostridiosis: C. perfringens, C. septicum, C. novyi (C. oedematiens), C. histolyticum and C. sordellii. C. histolyticum (65.2%), C. septicum (45.6), C. perfringens (29.7) and C. sporogenes (26.1) were isolated most frequently from cows and heifers, while C. sordellii (1.7) and C. novyi (0.9%) were isolated less frequently. Clostridium spp. bacteria of six species were isolated from animals in enterotoxemia and enteritis, and five species in vaginitis and endometritis. In other clinical forms of the disease, bacteria of four species were isolated from cows and heifers. The spectrum of bacteria involved in the development of abomasitis, enteritis and enterotoxemia in calves was similar and represented by four bacterial species: C. histolyticum, C. septicum, C. perfringens and C. sporogenes. Bacteria of five species were isolated from the calves with septicaemic form of the disease. The peculiarities of clinical manifestation and the course of clostridiosis in cattle depended on the species composition of pathogens and their associations. Diseases caused by Clostridium spp. bacteria were acute or subacute, characterized by visible lesions of organs and tissues in a few hours after the animal showed signs of disease and in most cases ended in death.

Gas-Spring Quasi-Zero Stiffness Air Damping Isolator for Vertical Vibration Control of Indoor Substation Excited by Metro Loads

To mitigate the metro-induced vertical vibration of the indoor substation structure, this study proposes a gas-spring quasi-zero stiffness air damping isolator (AD-QZSI) with excellent low dynamic stiffness and high-static stiffness characteristics. The working principle and mechanical properties of the AD-QZSI are introduced and studied through theoretical and numerical methods. A model for substation considering soil–structure–equipment interaction is established using the software ABAQUS, its accuracy is validated based on a series of measured data from actual projects, and the AD-QZSI’s simulation method and parameter design method are described in detail. The air damper’s stiffness [Formula: see text] is integrated into the isolator’s mechanical model, theoretically and numerically achieving an accurate simulation of AD-QZSI’s nonlinear mechanical properties. The numerical results have an error of less than 5% with the measured data, indicating that the model is able to better capture the actual structure’s dynamic characteristics and is reasonable to be employed for subsequent analysis. Numerical results show that AD-QZSI can significantly reduce the structural vertical vibration, and its control effect is better in the whole frequency band, in particular, the effect is also visible in the low-frequency band, indicating that its vibration isolation frequency band is wider than that of traditional QZS isolator. With the vibration source distance increasing, the control effect of AD-QZSI presents a tendency to decrease and then level off, and its vibration isolation gain is weakened by the continuous increase of the damping ratio greater than 0.01. Moreover, the equipment’s dynamic amplification factor of the isolated structure decreases significantly. Finally, the proposed AD-QZSI can obtain ideal quasi-zero stiffness characteristics by adjusting the air pressure, and the adopted air damper belongs to the green low-carbon components, featuring great practical value and application prospects.

Determination of fungal root and stem rot agents of melons grown in Kumluca/Antalya

Kumluca has an important place in terms of greenhouse vegetable cultivation. Melon is among one of the main vegetables grown in the district on about 3200 decare of land. Various diseases cause decrease in the yield and quality of melons grown undercover in Türkiye. Among them, Fusarium wilt and gummy stem blight diseases especially have caused significant losses in recent years. In this research, the incidence and severity of the root and stem rot disease in Kumluca were determined by surveys made in 72 melon greenhouses in this area. Plant and soil samples were taken to the laboratory and isolations were made. As a result, Fusarium oxysporum and Didymella bryoniae were the most frequently isolated pathogens from the plant samples, followed by other Fusarium species. Fungi with the highest isolation frequency from the soil samples were Fusarium spp., Rhizoctonia solani and Macrophomina phaseolina. In the pathogenicity test, F. oxysporum, F. solani, F. verticillioides, M. phaseolina and R. solani isolates caused severe symptoms on melon seedlings. Virulence of the F. oxysporum isolates on different cucurbit species was also investigated and it was determined that they caused severe wilting on melon and watermelon seedlings, while symptoms on squash and cucumber were moderate or slight. Additionally, reactions of five melon cultivars (Yusufbey, Çıtırex, Niovi, Ferdevs and Memory) commonly grown in the region against D. bryoniae were investigated using randomly selected four pathogen isolates. All the cultivars were susceptible to the disease.