Non-covalent interactions and charge transfer in the CO 2 activation by low-valent group 14 complexes.

CONTEXT: The CO 2 activation by low-valent group 14 catalysts encompasses the rupture of varied covalent bonds in a single transition state through a concerted pathway. The bond between the central main group atom and the hydride in the complex is elongated to trigger the formation of the C-H bond with CO 2 accompanied by the concomitant formation of the E-O bond between the complex and CO 2 to lead the corresponding formate product. Prior studies have established that besides the apolar nature of CO 2 , its initial interaction with the complex is primarily governed by electrostatic interactions. Notably, other stabilizing interactions and the transfer of charge between catalysts and CO 2 during the initial phases of the reaction have been ignored. In this study, we have quantified the non-covalent interactions and charge transfer that facilitate the activation of CO 2 by group 14 main group complex. Our findings indicate that electrostatic interactions predominantly stabilize the complex and CO 2 in the reactant region. However, induction energy becomes the main stabilizing force as the reaction progresses towards the transition state, surpassing electrostatics. Induction contributes about 50% to the stabilization at the transition state, followed by electrostatics (40%) and dispersion interactions (10%). Atomic charges calculated with the minimal basis iterative stockholder (MBIS) method reveal larger charge transfer for the back-side reaction path in which CO 2 approaches the catalysts in contrast to the front-side approach. Notably, it was discovered that a minor initial bending of CO 2 to approximately 176 ∘ initiates the charge transfer process for all systems. Furthermore, our investigation of group 14 elements demonstrates a systematic reduction in both activation energies and charge transfer to CO 2 while descending in group 14. METHODS: All studied reactions were characterized along the reaction coordinate obtained with the intrinsic reaction coordinate (IRC) methodology at the M06-2X/6-31 g(d,p) level of theory. Gibbs free energy in toluene was computed using electronic energies at the DLPNO-CCSD(T)/cc-pVTZ-SSD(E) level of theory. Vibrational and translational entropy corrections were applied to provide a more accurate description of the obtained Gibbs free energies. To better characterize the changes in the reaction coordinate for all reactions, the reaction force analysis (RFA) has been employed. It enables the partition of the reaction coordinate into the reactant, transition state, and product regions where different stages of the mechanism occur. A detailed characterization of the main non-covalent driving forces in the initial stages of the activation of CO 2 by low-valent group 14 complexes was performed using symmetry-adapted perturbation theory (SAPT). The SAPT0-CT/def2-SVP method was employed for these computations. Charge transfer descriptors based on atomic population using the MBIS scheme were also obtained to complement the SAPT analyses.

Characterization of Chlorhexidine Resistance Among Clinical Isolates of Coagulase-Negative Staphylococcus Species in a Tertiary Care Center, Chennai.

Background Coagulase-negative Staphylococci (CoNS) are potential pathogens and are often associated with healthcare-associated infections (HAIs). Chlorhexidine (CHX) is the most widely used antiseptic to reduce colonization and infection by all Staphylococci, including CoNS. Resistance to CHX among CoNS has been observed over the past few years, consequent to its widespread use. Phenotypic tolerance or reduced susceptibility to CHX is conferred by plasmid-mediated qac group of genes, mainly qacA/B and smr, which cause activation of efflux pumps over the bacterial cell wall. This study aims to characterize the phenotypic and genotypic resistance exhibited by CoNS species against CHX. Methods After ethical approval, 148 consecutive, non-repetitive isolates of clinically significant CoNS species of hospitalized patients, isolated from blood samples and exudative specimens, were included in the study. Speciation was performed by conventional biochemical identification and automated methods. Antimicrobial susceptibility testing was performed by disc diffusion technique and for vancomycin by minimum inhibitory concentration (MIC) determination, as per Clinical Laboratory Standards Institute (CLSI) M-100 2023 guidelines. Methicillin resistance was detected using a cefoxitin disc. MIC for CHX was performed by agar dilution method; reduced susceptibility was considered when MIC to CHX ≥4 µg/mL. The simplex polymerase chain reaction (PCR) was carried out with suitable controls to detect qacA/B and smr. Statistical analysis was conducted to determine the association of qacA/B and smr genes with MIC of CHX in the study isolates. Results Fifteen different species of CoNS were obtained from clinical samples. A high percentage of resistance was observed against various classes of antibiotics. Methicillin resistance was observed in 69.6% (103/148) of isolates. Of 148 CoNS, 52.7% (78/148) of isolates exhibited reduced susceptibility to CHX with an MIC ≥4 µg/mL. These isolates exhibited a higher percentage of methicillin resistance (75.6%, 59/78). By PCR, 34.5% (51/148) of isolates carried either or both genes. Gene qacA/B was solely detected in 27.02% (40/148) of isolates, of which 14 were CHX-tolerant and the remaining 26 were CHX-susceptible. Gene smr was solely detected in 4.1% (6/148) of isolates comprising three isolates each in CHX-tolerant and susceptible categories. There were 3.4% (5/148) of isolates that harbored both genes, of which only one isolate was CHX-susceptible, while the other four were CHX-tolerant. A proportion of isolates that were phenotypically tolerant to CHX did not carry either or both genes. A significant statistical association was found between reduced susceptibility to CHX and the presence of antiseptic resistance genes in the study isolates (p-value=0.033942). Conclusion To our knowledge, this is the first study from South India to investigate CHX resistance among CoNS using phenotypic and genotypic methods. The rise of antiseptic resistance among CoNS is an emerging threat to current infection control practices. The presence of qacA/B and smr genes, especially in CHX susceptible isolates, is concerning since these resistance genes are located on transferable plasmids, and the isolates can develop resistance eventually upon exposure to CHX.

Cationic covalent organic framework nanosheets as the coating layer of commercial separator for high-efficiency lithium-sulfur batteries.

Ion-selective separators, are crucial and in high demand for maximizing the performance of lithium-sulfur (Li-S) batteries, which can conduct lithium ions while efficiently blocking polysulfides. However, commercial separators cannot effectively block the shuttle of polysulfides after multiple cycles due to their large porosity and easy dissolution, resulting in a reduced battery life. Herein, a covalent organic framework nanosheets (CON) ion-coated separator is prepared on the commercial separator. Due to the smaller pore size of CON-TFSI compared to polysulfides, the CON-TFSI modified separator can effectively block the polysulfide from migrating across the separator. By incorporating this innovative functional layer, Li-S batteries demonstrate outstanding performance. In a Li-S battery featuring a sulfur loading of 0.6 mg/cm2, it attains an initial discharge specific capacity of up to 891.9 mA h g-1, and exhibits the capacity retention of 54.6 % after 500 cycles at a current density of 0.2 C. This work offers a fresh perspective on the advancement of high-performance membranes for Li-S batteries.

Antibiogram profiling and detection of icaA and blaZ genes from Staphylococcus aureus and coagulase-negative Staphylococcus spp. of healthy bovine raw milk sample origin.

Objective: This study focused on the antibiogram profiling of Staphylococcus aureus and coagulase-negative Staphylococcus spp. (CoNS) and the detection of icaA and blaZ genes from bovine raw milk samples. Materials and Methods: Bovine milk samples were collected from dairy farms, and Staphylococcus spp. were isolated and identified via conventional and molecular screening. Disk diffusion test (DDT) was implemented to determine the resistance pattern. Biofilm and ß-lactamase-producing Staphylococcus spp. were identified via amplification of the icaA and blaZ genes. Methicillin-resistant Staphylococcus aureus and CoNS were identified by DDT and PCR of the mecA gene. Results: From 63 samples, 35 were confirmed as Staphylococcus spp., of which 16 (25.39%) S. aureus isolates were coagulase-positive, while 19 (30.16%) were negative. PCR confirmed that 50% (8/16) of S. aureus and 36.84% (7/19) of CoNS possessed the icaA gene. All S. aureus isolates were found resistant to penicillin-G (P) both phenotypically and genotypically. The isolates were also resistant to erythromycin (ERY) and oxytetracycline (TET). While CoNS showed high to reduced resistance against P, TET, ERY, and azithromycin, no S. aureus isolates were resistant to sulfamethoxazole, while 10.53% of CoNS isolates were. All S. aureus and CoNS isolates were susceptible to vancomycin and gentamicin. MR was exhibited by 37.5% of S. aureus and 42.10% of CoNS isolates. Moreover, S. aureus and CoNS had 56.25% and 52.63% multidrug-resistant (MDR) isolates, respectively. Conclusion: The present study revealed the presence of a biofilm-producing, MDR staphylococcal strain in milk that might endanger consumers. Routine surveillance and monitoring, along with antimicrobial resistance learning, can reduce risks.

Carbon utilization and storage through rehabilitation of groundwater wells.

According to the Intergovernmental Panel on Climate Change (IPCC) of the United Nations (UN), rise in atmospheric concentration of carbon dioxide (CO 2 ) due to anthropogenic factors is considered as the primary driver for global climate change. With almost every major corporation around the world working towards their "net-zero goals", it is becoming increasingly important to have more technologies that can help reduce carbon footprint. Achieving sequestration of CO 2 in the subsurface through Carbon Capture Utilization and Storage (CCUS) technologies like CO 2 -Enhanced Oil Recovery, CO 2 -Enhanced Geothermal Systems, CO 2 -Enhanced Coal Bed Methane, etc. is well accepted. We introduce yet another attractive CCUS opportunity through well rehabilitation. Aqua Freed® and Aqua Gard® are well-known well rehabilitation and preventive well maintenance technologies that utilize (inject underground) liquid CO 2 for the purpose. The goal of this study was to quantify the storage capacity of Aqua Freed® and Aqua Gard®, and establish their CCUS credentials. Depending on the well being serviced, these technologies can inject up to 40 US tons of CO 2 per well. Based on field data collection and statistical modeling, we estimated that 82-96% (median 90%) of the injected CO 2 remains in the subsurface post injection. Overall, our results and analysis of the US market suggest that using CO 2 for well rehabilitation and maintenance has a storage potential of several megatonnes of CO 2 annually in the US alone.

A Retrospective Descriptive Study of Staphylococcus Species Isolated from Canine Specimens Submitted to a Diagnostic Laboratory in South Africa, 2012-2017.

There is a scarcity of published studies on the occurrence of Staphylococcus spp. Among dogs in South Africa. The objective of the study was to characterise the Staphylococcus spp. Isolated from dog samples submitted to a veterinary diagnostic laboratory in South Africa in terms of time, place, and person. This study utilised a dataset of 1627 positive Staphylococcus isolates obtained from a veterinary diagnostic laboratory in South Africa from 2012 to 2017. Out of the 1627 confirmed isolates, 10 different species of Staphylococcus were identified. Among these, 92.0% were classified as coagulase-positive staphylococci (CoPS), 6.0% were coagulase-negative staphylococci (CoNS), and 3.0% were coagulase-variable. Male dogs contributed just over half (53.2%) of the Staphylococcus isolates, while female dogs contributed the remaining 46.8%. The largest proportion of isolates (23.2%) were obtained from dogs aged ≥ 9 years, with the highest number of isolates originating from KwaZulu-Natal Province (45.0%) and the least from Northern Cape Province (0.1%). Out of the total samples included in the records, the majority (46.0%) were skin specimens. The number of Staphylococcus isolates recorded showed limited variation between the seasons (24.3% in autumn, 26.3% in winter, 26.0% in spring, and 24.0% in summer). This study highlighted the diversity of Staphylococcus spp. isolated from dogs, and the burden of staphylococcal carriage among dogs in South Africa. Further research is required to examine the factors that contribute to the observed discrepancies in the proportions of Staphylococcus spp. between the provinces.

Co-resistance to methicillin and clindamycin among coagulase-negative staphylococci isolates recovered from pet food in Brazil.

Pet food have been considered as possible vehicles of bacterial pathogens. The sudden boom of the pet food industry due to the worldwide increase in companion animal ownership calls for pet food investigations. Herein, this study aimed to determine the frequency, antimicrobial susceptibility profile, and molecular characteristics of coagulase-negative staphylococci (CoNS) in different pet food brands in Brazil. Eighty-six pet food packages were screened for CoNS. All isolates were identified at species level by MALDI-TOF MS and species-specific PCR. Antimicrobial susceptibility testing was performed by disc diffusion and broth microdilution (vancomycin and teicoplanin only) methods. The D-test was used to screen for inducible clindamycin phenotype (MLS-B). SCCmec typing and detection of mecA, vanA, vanB, and virulence-encoding genes were done by PCR. A total of 16 (18.6 %) CoNS isolates were recovered from pet food samples. Isolates were generally multidrug-resistant (MDR). All isolates were completely resistant (100 %) to penicillin. Resistances (12.5 % - 75 %) were also observed for fluoroquinolones, sulfamethoxazole-trimethoprim, tetracycline, rifampicin, erythromycin, and tobramycin. Isolates were susceptible to vancomycin (MICs <0.25-1 µg/mL) and teicoplanin (MICs <0.25-4 µg/mL). Intriguingly, 3/8 (37.5 %) CoNS isolates with the ERYRCLIS antibiotype expressed MLS-B phenotype. All isolates harboured blaZ gene. Seven (43.8 %) isolates carried mecA; and among them, the SCCmec Type III was the most frequent (n = 5/7; 71.4 %). Isolates also harboured seb, see, seg, sej, sem, etb, tsst, pvl, and hla toxin virulence-encoding genes (6.3 % - 25 %). A total of 12/16 (75 %) isolates were biofilm producers, while the icaAB gene was detected in an S. pasteuri isolate. Herein, it is shown that pet food is a potential source of clinically important Gram-positive bacterial pathogens. To the best of our knowledge, this is the first report of MLS-B phenotype and MR-CoNS in pet food in Latin America.

Advanced photocatalysis as a viable and sustainable wastewater treatment process: A comprehensive review.

In our era, water pollution not only poses a serious threat to human, animal, and biotic life but also causes serious damage to infrastructure and the ecosystem. A set of physical, chemical, and biological technologies have been exploited to decontaminate and/or disinfect water pollutants, toxins, microbes, and contaminants, but none of these could be ranked as sustainable and scalable wastewater technology. The photocatalytic process can harmonize the sunlight to degrade certain toxins, chemicals, microbes, and antibiotics, present in water. For example, transition metal oxides (ZnO, SnO2, TiO2, etc.), when integrated into an organic framework of graphene or nitrides, can bring about more than 90% removal of dyes, microbial load, pesticides, and antibiotics. Similarly, a modified network of graphitic carbon nitride can completely decontaminate petrochemicals. The present review will primarily highlight the mechanistic aspects for the removal and/or degradation of highly concerned contaminants, factors affecting photocatalysis, engineering designs of photoreactors, and pros and cons of various wastewater treatment technologies already in practice. The photocatalytic reactor can be a more viable and sustainable wastewater treatment opportunity. We hope the researcher will find a handful of information regarding the advanced oxidation process accomplished via photocatalysis and the benefits associated with the photocatalytic-type degradation of water pollutants and contaminants.

Antibiotic Susceptibility and Biofilm Production among Coagulase Negative Staphylococci Isolated from Clinical Samples at Tertiary Care Hospital.

BACKGROUND: Coagulase Negative Staphylococci have been widely associated with medical device implant treatment and immune-compromised patients. Despite having increasing interest in Coagulase Negative Staphylococci, few studies from Nepal have reported the association of these organisms with urinary tract infections, conjunctivitis, high vaginal swabs, and cerebrospinal fluid. This study was carried out to determine antibiotic susceptibility pattern and biofilm production among Coagulase Negative Staphylococci isolated from clinical samples at tertiary care hospital. METHODS: This study was a hospital based cross-sectional study in which 3690 clinical samples were included. Isolation and identification of isolates was done following standard microbiological protocol. Coagulase Negative Staphylococci were identified phenotypically on the basis of gram staining, slide and tube coagulase test and by various sugar fermentation tests. Antibiotic susceptibility test was done following Kirby Bauer disk diffusion method (Clinical and Laboratory Standards Institute 2020). Biofilm production was determined by Tissue Culture Plate technique. RESULTS: A total of 113 isolates of Coagulase Negative Staphylococci were detected. Among them S. epidermidis (45.1%), S. saprophyticus (23.9%), S. haemolyticus (16.8%), S. hominis (5.3%), S. capitis (2.7%), -----S. cohini (1.8%), S. lugdunensis (1.8%) and S. sciuri (2.7%) were identified phenotypically. All isolates were found to be resistant against Ampicillin and 111 (98.2%) were sensitive against Linezolid.23.9% of CoNS were strong biofilm producers, 19.5% moderate and 56.6 % were non/weak biofilm producers. CONCLUSIONS: It requires susceptibility test for prescribing antibiotics against Coagulase Negative Staphylococci in hospital and the misuse of antibiotics should be prevented.

Perspective: How can risks to patients be limited during spine surgeons' learning curves?

Background: Learning curves (LC) are typically defined by the number of different spinal procedures surgeons must perform before becoming "proficient," as demonstrated by reductions in operative times, estimated blood loss (EBL), length of hospital stay (LOS), adverse events (AE), fewer conversions to open procedures, along with improved outcomes. Reviewing 12 studies revealed LC varied widely from 10-44 cases for open vs. minimally invasive (MI) lumbar diskectomy, laminectomy, transforaminal lumbar interbody fusion (TLIF), anterior lumbar interbody fusion (ALIF), and oblique/extreme lateral interbody fusions (OLIF/XLIF). We asked whether the risks of harm occurring during these LC could be limited if surgeons routinely utilized in-person/intraoperative mentoring (i.e., via industry, academia, or well-trained colleagues). Methods: We evaluated LC for multiple lumbar operations in 12 studies. Results: These studies revealed no LC for open vs. MI lumbar diskectomy. LC required 29 cases for MI laminectomy, 10-44 cases for MI TLIF, 24-30 cases for MI OLIF, and 30 cases for XLIF. Additionally, the LC for MI ALIF was 30 cases; one study showed that 32% of major vascular injuries occurred in the first 25 vs. 0% for the next 25 cases. Shouldn't the risks of harm to patients occurring during these LC be limited if surgeons routinely utilized in-person/intraoperative mentoring? Conclusions: Twelve studies showed that the LC for at different MI lumbar spine operations varied markedly (i.e., 10-44 cases). Wouldn't and shouldn't spine surgeons avail themselves of routine in-person/intraoperative mentoring to limit patients' risks of injury during their respective LC for these varied spine procedures ?

Staphylococcus haemolyticus: An updated review on nosocomial infections, antimicrobial resistance, virulence, genetic traits, and strategies for combating this emerging opportunistic pathogen.

Staphylococcus haemolyticus, a key species of the Staphylococcus genus, holds significant importance in healthcare-associated infections, due to its notable resistance to antimicrobials, like methicillin, and proficient biofilms-forming capabilities. This coagulase-negative bacterium poses a substantial challenge in the battle against nosocomial infections. Recent research has shed light on Staph. haemolyticus genomic plasticity, unveiling genetic elements responsible for antibiotic resistance and their widespread dissemination within the genus. This review presents an updated and comprehensive overview of the clinical significance and prevalence of Staph. haemolyticus, underscores its zoonotic potential and relevance in the one health framework, explores crucial virulence factors, and examines genetics features contributing to its success in causing emergent and challenging infections. Additionally, we scrutinize ongoing studies aimed at controlling spread and alternative approaches for combating it.

Daptomycin Use for Persistent Coagulase-Negative Staphylococcal Bacteremia in a Neonatal Intensive Care Unit.

During the last two decades, the incidence of late-onset sepsis (LOS) has increased due to improved survival of premature neonates. Persistent bacteremia (PB) in LOS is defined as more than two positive blood cultures obtained on different calendar days during the same infectious episode. Although rare, PB should be treated aggressively to prevent adverse outcomes. Daptomycin, a lipopeptide antibiotic, has been used in neonates with persistent coagulase-negative staphylococci (CoNS) bacteremia with promising results, but studies reporting on the efficacy and safety of the agent are scarce. The purpose of this study was to evaluate the efficacy and safety of daptomycin use for persistent CoNS bacteremia in a neonatal cohort. This is a retrospective, observational, single-center study of neonates treated with daptomycin during 2011-2022 in the Tertiary Neonatal Intensive Care Unit (NICU) of the University General Hospital of Patras, Greece. For the years 2011-2022, there were 3.413 admissions to the NICU. During the last 3 years (2020-2022)-the active epidemiological surveillance period-123 infants (out of 851 admissions, 14.4%) developed CoNS bacteremia (LOS). During the study period, twelve infants with PB were treated with daptomycin. They had a median gestational age of 32 weeks (IQR 31-34) and mean (SD) birth weight of 1.840 (867) grams. CoNS bacteremia isolates were s. epidermidis (50%), s. haemolyticus (20%), s. hominis (20%) and s. warneri (10%). The decision to start daptomycin (6 mg/kg/dose twice daily) was taken on median day 10 (ΙQR 7-15) of infection. None of the infants had focal complications or meningitis. Daptomycin therapy caused no renal, hepatic, muscular or gastrointestinal adverse events. One neonate developed seizures, and one death occurred due to multiple complications of prematurity. Most infants (11/12) were successfully treated and eventually had negative blood culture. Daptomycin monotherapy showed an adequate cure rate in premature neonates with persistent CoNS bacteremia in a tertiary NICU. In our study, daptomycin was effective and well tolerated; the safety profile, however, needs to be confirmed in larger studies and randomized controlled trials.

Genetic Diversification and Resistome of Coagulase-Negative Staphylococci from Nostrils of Healthy Dogs and Dog-Owners in La Rioja, Spain.

Coagulase-negative staphylococci (CoNS) species in healthy dogs and their owners could be transferred between these hosts and carry diverse antimicrobial resistance (AMR) genes of public health concern. This study determined the frequency, diversity, and AMR genes of nasal CoNS from healthy dogs and in-contact people as well as the rate of intra-household (between healthy dogs and dog-owners) transmission of CoNS. Nasal samples were collected and processed from 34 dogs and 41 humans from 27 households, and CoNS identification was done by MALDI-TOF-MS. The AMR determinants and genetic lineages were determined by PCR/sequencing. A total of 216 CoNS isolates were initially obtained and identified, and the AMR phenotypes were determined. From these, 130 non-repetitive CoNS were selected (one isolate of each species per sample or more than one if they presented different AMR phenotypes) and further characterized. The predominant species from dog carriers were S. epidermidis (26.5%), S. hominis (8.8%), and S. cohnii (8.8%), whereas in the human carriers, the predominant ones were S. epidermidis (80.4%), S. lugdunensis (9.8%), and S. hominis (9.8%). Intra-host species diversity (>one CoNS species) was detected in 37.5% of dogs and 21.6% of dog-owners. Conversely, 50% of dogs and 70.3% of dog-owners had intra-species AMR diversity (2-4 AMR-CoNS profiles). About 20% were susceptible to all antimicrobial agents tested, 31.5% displayed a multidrug resistance phenotype, and 17.4% were mecA-positive, located in SCCmec type V (24.2%), III (18.1%), IVc (12.1%), and II (6.1%). The other mec-A positive CoNS isolates (39.5%) had non-typeable SCCmec. The highest AMR rates were found against erythromycin (32.3%/mph(C), msr(A)) and mupirocin (20.8%/mupA), but the resistance rates for other antimicrobial agents were <10% each. Remarkably, one linezolid-resistant S. epidermidis-ST35 isolate was identified and mediated by four amino acid substitutions in L3 and one in L4 ribosomal proteins. Dogs and dog-owners as carriers of S. epidermidis with similar AMR patterns and genetic lineages (ST59, ST61, ST166 and ST278) were detected in four households (14.8%). Diverse CoNS carriage and moderate level of AMR were obtained from this study. The detection of CoNS carrying diverse SCCmec elements and intra-species AMR diversity highlights the roles of dog ownership in the potential transmission of antimicrobial-resistant CoNS in either direction.

Staphylococcus capitis Central-Line-Associated Bloodstream Infections in the Neonatal Intensive Care Unit: A Single-Center, Four-Year Experience in Central-Line Management during Sepsis Treatment.

Coagulase-negative staphylococci (CoNS) are reportedly responsible for 50-60% of bloodstream infections in very preterm (<1500 g) infants in neonatal intensive care units (NICUs). Staphylococcus capitis is an increasingly prevalent pathogen in the neonatal setting, frequently causing central-line-associated bloodstream infections (CLABSIs) that can be difficult to eradicate. Central venous catheter (CVC) removal versus in situ treatment with CoNS CLABSIs is a controversial treatment strategy with no clear consensus. We reviewed all S. capitis CLABSIs in our NICU between 2019 and 2022, focusing on the role of catheter removal in eradication. Among the 25 patients, 17 CVCs were removed after diagnosis, leading to a 76.5% eradication rate in this group. Three infants had a persistently positive blood culture after CVC substitution. A new catheter was then inserted after a 48 h washout period, resulting in resolution of the infection. Only two of the eight patients (25%) who retained their catheter after diagnosis achieved infection eradication with antibiotic therapy alone. When feasible, catheter removal seems to be the most effective strategy for eradicating S. capitis CLABSIs, sometimes even requiring a 48 h washout period before reinsertion. Further studies on this topic are needed to better standardize the management of this type of infection.

Coagulase-negative staphylococci are the main causes of bacterial meningitis in duck.

Since September 2018, serious meningitis has been found on some breeding-duck farms in Shandong Province, China. A large number of ducks exhibit severe neurological symptoms. The ducks were randomly selected for laboratory testing. Duck brain samples were collected using standard sterile techniques, and the staphylococci isolates were detected in 404 (70.14%) out of 576 brain samples. A total of 525 coagulase-negative staphylococci (CoNS) strains were isolated, including 6 species: Staphylococcus sciuri (S. sciuri) (67.24%, 353/525), Staphylococcus epidermidis (S. epidermidis) (9.71%, 51/525), Staphylococcus saprophyticus (S. saprophyticus) (8.38%, 44/525), Staphylococcus lentus (S. lentus) (7.62%, 40/525), Staphylococcus haemolyticus (S. haemolyticus) (2.48%, 13/525), and Staphylococcus xylosus (S. xylosus) (4.57%, 24/525). Mixed strain infections were detected in 121 (29.95%) infected presentations. The antimicrobial susceptibility testing indicated that 40.38% of the isolates exhibited multi-drug resistance, and 53.90% of the strains were methicillin-resistant strains by amplification of the methicillin resistance gene (mecA) gene. Through experimental reproduction of the disease, we determined that the CoNS strains were the leading pathogens causing bacterial meningitis in ducks. Although these CoNS strains does not directly cause the death of sick ducks, they still cause large economic losses due to the retarded growth and development of the sick ducks, lower feed returns, and lower grades of processed duck products. The results of this study will contribute to our understanding of the epidemiology and pathogenesis of CoNS and be helpful in the prevention and treatment of the infection.

Characterization of virulence factors and antimicrobial resistance in Staphylococcus spp. isolated from clinical samples.

The virulence factors, antibiotic resistance patterns, and the associated genetic elements have been investigated in Staphylococcus species. A total of 100 strains has been isolated from clinical samples in the Microbiology Laboratory of Hesperia Hospital, Modena, Italy, and identified as Staphylococcus aureus (65), Staphylococcus epidermidis (24), Staphylococcus hominis (3), Staphylococcus saprophyticus (3), and Staphylococcus warneri (5). All the strains were analyzed to determine phenotypic and genotypic characters, notably the virulence factors, the antibiotics susceptibility, and the genetic determinants. The highest percentage of resistance in Staphylococcus spp. was found for erythromycin and benzylpenicillin (87% and 85%, respectively). All S. aureus, two S. epidermidis (8.3%), and one S. saprophyticus (33.3%) strains were resistant to oxacillin. The methicillin resistance gene (mecA) was detected by polymerase chain reaction (PCR) amplification in 65 S. aureus strains and in 3 coagulase-negative staphylococci (CoNS) (8.6%). With regard to the virulence characteristics, all the S. aureus were positive to all virulence tests, except for slime test. Among the CoNS isolates, 19 (79.1%) S. epidermidis and one (33.3%) S. saprophyticus strains resulted positive for the slime test only. The results obtained are useful for a more in-depth understanding of the function and contribution of S. aureus and CoNS antibiotic resistance and virulence factors to staphylococcal infections. In particular, the production of slime is very important for CoNS, a virulence factor frequently found in infections caused by these strains. Further investigations on the genetic relatedness among strains of different sources will be useful for epidemiological and monitoring purposes and will enable us to develop new strategies to counteract the diffusion of methicillin-resistant S. aureus (MRSA) and CoNS strains not only in clinical field, but also in other related environments.

Rigidifying AIEgens in covalent organic framework nanosheets for electrochemiluminescence enhancement: TABE-PZ-CON as a novel emitter for microRNA-21 detection.

Enhancing electrochemiluminescence (ECL) properties of luminophores is a hot direction in the current ECL field. Herein, we found that covalent rigidification of the aggregation-induced emission luminogens (AIEgens) TABE (TABE = tetra-(4-aldehyde-(1,1-biphenyl))ethylene) into covalent organic framework nanosheets (TABE-PZ-CON, PZ = piperazine) could result in stronger ECL emission than those of TABE aggregates and TABE monomers. We termed the interesting phenomenon "covalent rigidification-triggered electrochemiluminescence (CRT-ECL) enhancement". The superior ECL performance of TABE-PZ-CON not only because massive TABE luminogens were covalently assembled into the rigid TABE-PZ-CON network, which limited the intramolecular motions of TABE and hampered the radiationless transition, but also because the ultrathin porous TABE-PZ-CON significantly reduced the transportation distance of ions, electrons, and coreactants, which enabled the electrochemical excitation of more TABE luminogens and thus enhanced the ECL efficiency. Bearing in mind the exceptional ECL performance of TABE-PZ-CON, it was utilized as a high-efficient ECL indicator in combination with the DNA walker and duplex-specific nuclease-assisted target recycling amplification strategies to design an "off-on" ECL biosensor for the ultrasensitive assay of microRNA-21, exhibiting a favorable response range (100 aM-1 nM) with an ultralow detection limit of 17.9 aM. Overall, this work offers a valid way to inhibit the intramolecular motions of AIEgens for ECL enhancement, which gives a new vision for building high-performance AIEgen-based ECL materials, thus offering more chances for assembling hypersensitive ECL biosensors.

Pros and Cons on Use of Live Viral Vaccines in Commercial Chicken Flocks.

The poultry industry is the largest source of meat and eggs for the growing human population worldwide. Key concerns in poultry farming are nutrition, management, flock health, and biosecurity measures. As part of the flock health, use of live viral vaccines plays a vital role in the prevention of economically important and common viral diseases. This includes diseases and production losses caused by Newcastle disease virus, infectious bronchitis virus, infectious laryngotracheitis virus, infectious bursal disease virus, Marek's disease virus, chicken infectious anemia virus, avian encephalomyelitis virus, fowlpox virus, and avian metapneumovirus. These viruses cause direct and indirect harms, such as financial losses worth millions of dollars, loss of protein sources, and threats to animal welfare. Flock losses vary by type of poultry, age of affected animals, co-infections, immune status, and environmental factors. Losses in broiler birds can consist of high mortality, poor body weight gain, high feed conversion ratio, and increased carcass condemnation. In commercial layers and breeder flocks, losses include higher than normal mortality rate, poor flock uniformity, drops in egg production and quality, poor hatchability, and poor day-old-chick quality. Despite the emergence of technology-based vaccines, such as inactivated, subunit, vector-based, DNA or RNA, and others, the attenuated live vaccines remain as important as before. Live vaccines are preferred in the global veterinary vaccine market, accounting for 24.3% of the global market share in 2022. The remaining 75% includes inactivated, DNA, subunit, conjugate, recombinant, and toxoid vaccines. The main reason for this is that live vaccines can induce innate, mucosal, cellular, and humoral immunities by single or multiple applications. Some live vaccine combinations provide higher and broader protection against several diseases or strains of viruses. This review aimed to explore insights on the pros and cons of attenuated live vaccines commonly used against major viral infections of the global chicken industry, and the future road map for improvement.

Estudio recapitulativo- Pros y contras del uso de vacunas virales vivas en parvadas de pollos comerciales. La industria avícola es la mayor fuente de carne y huevos para la creciente población humana en todo el mundo. Las principales preocupaciones en la avicultura son la nutrición, el manejo, la salud de las parvadas y las medidas de bioseguridad. Como parte de la salud de las parvadas avícolas, el uso de vacunas virales vivas juega un papel vital en la prevención de enfermedades virales comunes y de importancia económica. Esto incluye enfermedades y pérdidas en la producción causadas por el virus de la enfermedad de Newcastle, el virus de la bronquitis infecciosa, el virus de la laringotraqueítis infecciosa, el virus de la enfermedad infecciosa de la bolsa, el virus de la enfermedad de Marek, el virus de la anemia infecciosa del pollo, el virus de la encefalomielitis aviar, el virus de la viruela aviar y el metapneumovirus aviar. Estos virus causan daños directos e indirectos, como pérdidas financieras valoradas en millones de dólares, pérdida de fuentes de proteínas y amenazas al bienestar animal. Las pérdidas en las parvadas avícolas varían según el tipo de aves, la edad de los animales afectados, las coinfecciones, el estado inmunológico y los factores ambientales. Las pérdidas en aves de engorde pueden consistir en una alta mortalidad, un pobre aumento de peso corporal, un alto índice de conversión alimenticia y un mayor decomiso de las canales. En las gallinas de postura comerciales y en las parvadas de reproductoras, las pérdidas incluyen una tasa de mortalidad superior a la normal, una escasa uniformidad de la parvada, caídas en la producción y calidad de los huevos, una pobre incubabilidad y una mala calidad de los pollitos de un día. A pesar de la aparición de vacunas de base tecnológica, como las inactivadas, subunitarias, vectoriales, de ADN o ARN, entre otras, las vacunas vivas atenuadas siguen siendo tan importantes como antes. Las vacunas vivas son las preferidas en el mercado mundial de vacunas para uso veterinario y representaron el 24.3% de la cuota de mercado mundial en el año 2022. El 75% restante incluye vacunas inactivadas, de ADN, de subunidades, conjugadas, recombinantes y toxoides. La razón principal de esto es que las vacunas vivas pueden inducir inmunidad innata, de mucosas, celular y humoral mediante aplicaciones únicas o múltiples. Algunas combinaciones de vacunas vivas brindan una protección mayor y más amplia contra varias enfermedades o cepas de virus. Esta revisión tuvo como objetivo explorar ideas sobre los pros y los contras de las vacunas vivas atenuadas comúnmente utilizadas contra las principales infecciones virales de la industria avícola mundial, y las rutas futuras para mejorar.

Resistome, mobilome, and virulome explored in clinical isolates derived from acne patients in Egypt: unveiling unique traits of an emerging coagulase-negative Staphylococcus pathogen.

Coagulase-negative staphylococci (CoNS) are a group of gram-positive staphylococcal species that naturally inhabit the healthy human skin and mucosa. The clinical impact of CoNS-associated infections has recently been regarded as a challenge for diagnosis and therapeutic options. CoNS-associated infections are primarily caused by bacterial resistance to antibiotics and biofilm formation. As antibiotics are still the most used treatment, this problem will likely persist in the future. The present study aimed to investigate the resistance and virulence of CoNS recovered from various acne lesions and explore their genetic basis. Skin swab samples were collected from participants with acne and healthy skin. All samples underwent conventional culture for the isolation of CoNS, MALDI-TOF confirmation, antibiotic susceptibility, and biofilm formation testing. A total of 85 CoNS isolates were recovered from the samples and preliminarily identified as Staphylococcus epidermidis. Isolates from the acne group (n = 60) showed the highest rates of resistance to penicillin (73%), cefoxitin (63%), clindamycin (53.3%), and erythromycin (48%), followed by levofloxacin (36.7%) and gentamycin (31.7%). The lowest rates of resistance were observed against tetracycline (28.3%), doxycycline (11.7%), and minocycline (8.3%). CoNS isolated from mild, moderate acne and healthy isolates did not show strong biofilm formation, whereas the isolates from the severe cases of the acne group showed strong biofilm formation (76.6%). Four extensively drug-resistant and strong biofilm-forming staphylococcal isolates recovered from patients with severe acne were selected for whole-genome sequencing (WGS), and their genomes were investigated using bioinformatics tools. Three of the sequenced genomes were identified as S. epidermidis; however, isolate 29AM was identified as Staphylococcus warneri, which is a newly emerging pathogen that is not commonly associated with acne and was not detected by MALDI-TOF. All the sequenced strains were multidrug-resistant and carried multiple resistance genes, including blaZ, mecA, tet(K), erm(C), lnuA, vgaA, dfrC, fusB, fosBx1, norA, and vanT, which were found to be located on plasmids and chromosomes. Virulence features were detected in all genomes in the presence of genes involved in adherence and biofilm formation (icaA, icaB, icaC, sdrG, sdrH, atl, ebh, and ebp). Only the S. warneri isolate 29AM contained immune evasion genes (capB, capC, acpXL, and manA), an anti-phagocytosis gene (cdsA), and other unique features. As a result of their potential pathogenicity and antibiotic resistance, CoNS must be monitored as an emerging pathogen associated with acne infections. To the best of our knowledge, this is the first report to isolate, identify, and correlate S. warneri with severe acne infections among Egyptian patients using WGS and bioinformatic analysis.