Increase In Multidrug-resistant Bacteria Research Articles

Whole-genome sequencing of Klebsiella pneumoniae MDR circulating in a pediatric hospital setting: a comprehensive genome analysis of isolates from Guayaquil, Ecuador

BackgroundKlebsiella pneumoniae is the major cause of nosocomial infections worldwide and is related to a worsening increase in Multidrug-Resistant Bacteria (MDR) and virulence genes that seriously affect immunosuppressed patients, long-stay intensive care patients, elderly individuals, and children. Whole-Genome Sequencing (WGS) has resulted in a useful strategy for characterizing the genomic components of clinically important bacteria, such as K. pneumoniae, enabling them to monitor genetic changes and understand transmission, highlighting the risk of dissemination of resistance and virulence associated genes in hospitals. In this study, we report on WGS 14 clinical isolates of K. pneumoniae from a pediatric hospital biobank of Guayaquil, Ecuador.ResultsThe main findings revealed pronounced genetic heterogeneity among the isolates. Multilocus sequencing type ST45 was the predominant lineage among non-KPC isolates, whereas ST629 was found more frequently among KPC isolates. Phylogenetic analysis suggested local transmission dynamics. Comparative genomic analysis revealed a core set of 3511 conserved genes and an open pangenome in neonatal isolates. The diversity of MLSTs and capsular types, and the high genetic diversity among these isolates indicate high intraspecific variability. In terms of virulence factors, we identified genes associated with adherence, biofilm formation, immune evasion, secretion systems, multidrug efflux pump transporters, and a notably high number of genes related to iron uptake. A large number of these genes were detected in the ST45 isolate, whereas iron uptake yersiniabactin genes were found exclusively in the non-KPC isolates. We observed high resistance to commonly used antibiotics and determined that these isolates exhibited multidrug resistance including β-lactams, aminoglycosides, fluoroquinolones, quinolones, trimetropins, fosfomycin and macrolides; additionally, resistance-associated point mutations and cross-resistance genes were identified in all the isolates. We also report the first K. pneumoniae KPC-3 gene producers in Ecuador.ConclusionsOur WGS results for clinical isolates highlight the importance of MDR in neonatal K. pneumoniae infections and their genetic diversity. WGS will be an imperative strategy for the surveillance of K. pneumoniae in Ecuador, and will contribute to identifying effective treatment strategies for K. pneumoniae infections in critical units in patients at stratified risk.

Tailoring Mesoporous Silica-Coated Silver Nanoparticles and Polyurethane-Doped Films for Enhanced Antimicrobial Applications.

The global increase in multidrug-resistant bacteria poses a challenge to public health and requires the development of new antibacterial materials. In this study, we examined the bactericidal properties of mesoporous silica-coated silver nanoparticles, varying the core sizes (ca. 28 nm and 51 nm). We also investigated gold nanoparticles (ca. 26 nm) coated with mesoporous silica as possible inert metal cores. To investigate the modification of antimicrobial activity after the surface charge change, we used silver nanoparticles with a silver core of 28 nm coated with a mesoporous shell (ca. 16 nm) and functionalized with a terminal amine group. Furthermore, we developed a facile method to create mesoporous silica-coated silver nanoparticles (Ag@mSiO2) doped films using polyurethane (IROGRAN®) as a polymer matrix via solution casting. The antibacterial effects of silver nanoparticles with different core sizes were analyzed against Gram-negative and Gram-positive bacteria relevant to the healthcare and food industry. The results demonstrated that gold nanoparticles were inert, while silver nanoparticles exhibited antibacterial effects against Gram-negative (Escherichia coli and Salmonella enterica subsp. enterica serovar Choleraesuis) and Gram-positive (Bacillus cereus) strains. In particular, the larger Ag@mSiO2 nanoparticles showed a minimum inhibitory concentration (MIC) and a minimum bactericidal concentration (MBC) of 18 µg/mL in the Salmonella strain. Furthermore, upon terminal amine functionalization, reversing the surface charge to positive values, there was a significant increase in the antibacterial activity of the NPs compared to their negative counterparts. Finally, the antimicrobial properties of the nanoparticle-doped polyurethane films revealed a substantial improvement in antibacterial efficacy. This study provides valuable information on the potential of mesoporous silica-coated silver nanoparticles and their applications in fighting multidrug-resistant bacteria, especially in the healthcare and food industries.

Increase of multidrug-resistant bacteria after the COVID-19 pandemic in a major teaching Hospital in Sicily (2018-2021)

IntroductionThe COVID-19 pandemic has further highlighted the continuing threat of antimicrobial resistance (AMR) to global health and economic development. In the last two decades, AMR has raised increasing concern, with an estimated 4.95 million deaths globally due to bacterial AMR in 2019 alone.The aim of this study was to analyse the impact of the pandemic on the spread of multidrug-resistant organisms (MDROs) using data from the Hospital “P. Giaccone” in Palermo, comparing pre-pandemic and pandemic periods. MethodsThis observational study involved adult patients who were discharged from the hospital between 01 January 2018 and 31 December 2021. Hospital Discharge Cards were linked with microbiological laboratory reports to assess MDRO isolations. SARS-CoV-2 positivity during hospitalisation was evaluated using the National Institute of Health surveillance system. ResultsA total of 58 427 hospitalisations were evaluated in this study. Half the patients were aged over 65 years (N=26 984) and most admissions were in the medical area (N=31 716). During the hospitalisation period, there were 2681 patients (5%) with MDROs isolations, and 946 patients (2%) were positive for SARS-CoV-2. Multivariable analyses showed that during 2020 and 2021, there was a significantly increased risk of isolation of Staphylococcus aureus, Acinetobacter baumannii, and Klebsiella pneumoniae. Age, weight of the Diagnosis-Related Group (DRG), wards with higher intensity of care, and length-of-stay were associated with a higher risk of MDRO isolation. ConclusionThis study provides new insights into the impact of the COVID-19 pandemic on MDRO isolation and has important implications for infection control and prevention efforts in healthcare facilities. Age, DRG-weight, and longer hospital stays further increased the risk of MDRO isolation. Thus, it is imperative to improve and follow hospital protocols to prevent healthcare-associated infections.

Microbiological Air Quality and Antibiotic Resistance in Isolated Bioaerosols from Various Activities in Zanjan, Iran

Introduction: The aim of this study is the isolation and primary identification of isolated bioaerosols sampled from different locations, as well as determining their antibiotic resistance profile for the selected bacteria.
 Materials and Methods: The air samples were collected from 35 stations in 17 buildings (bank, public, healthcare and industrial). An air-sampling pump (Flite3-SKC) with a flow rate of 14.1 l/min was used for five minutes at the respiratory height. The total bacterial count and primary identification were carried out, then the antibiotic susceptibility tests for ten selected antibiotics were conducted by the disk diffusion method. 
 Results: The bacterial population varied at a range of 128-5503 CFU/m3, and the fruit and vegetable bazaar of Zanjan showed the highest population of bioaerosols. The bioaerosols population among industrial samples was high. Most isolates were determined as gram-positive Cocci (> 70%) and Bacillus spp, respectively. The most antibiotic-resistant bacteria were related to manufacturing activities, showing resistance to Chloramphenicol and Trimethoprim/ Sulfamethoxazole (72%).
 Conclusion: The type of activity affects the bacterial population and antibiotic resistance in industrial uses. The increase of multi-drug resistant bacteria, especially in medical settings, is known as a community health challenge and needs more attention.

Treatment of Ventriculitis and Meningitis After Neurosurgery Caused by Carbapenem-Resistant Enterobacteriaceae (CRE): A Challenging Topic.

Post-neurosurgical infection is a common complication of neurosurgery, and serious infection can threaten the life of patients. In recent years, the increase in multidrug-resistant bacteria, especially carbapenem-resistant Enterobacteriaceae (CRE), has proved fatal to patients. Although there are a few cases of CRE meningitis and few clinical trials have been carried out, it has attracted increasing attention with the increasing probability of its occurrence, especially considering that there are few successful cases. An increasing number of studies are also looking for the risk factors and clinical symptoms of CRE intracranial infection. In terms of treatment, some new antibiotics are gradually being used in the clinic, but due to the complicated drug-resistant mechanism of CRE and the obstruction of the blood‒brain barrier (BBB), the therapeutic effect is still very poor. In addition, obstructive hydrocephalus and brain abscess caused by CRE meningitis are still important causes of patient death and are also difficult to treat.

Sodium Salicylate as Feed Additive in Broilers: Absence of Toxicopathological Findings.

Antimicrobial growth promoters (AGPs) in animal production have been related to the increase in multidrug-resistant bacteria. The AGP ban in many countries has highlighted the growing need for alternatives for feed additives. Considering the non-antibiotic anti-inflammatory theory of AGPs, chicks received three different doses of sodium salicylate (SS) in feed (10, 30, 90 mg/kg), basal diet (BD) was used as a negative control, and zinc bacitracin (ZB) was used as a positive control. Chicks were individually housed to increase the accuracy of the dose of SS ingested. Performance parameters and footpad dermatitis were evaluated weekly, while haematology, serum biochemistry, histopathology, and tibial dyschondroplasia were determined on Days 21 and 42. A linear dose-dependent decrease in haemoglobin concentration was observed, but the values were within the normal reference range. Among all the other evaluated parameters, no relevant differences between treatments were observed; however, not even the AGP group performed better than the control group. It is possible that the conditions in which the birds were raised were not stressful enough to allow for anti-inflammatories to demonstrate their beneficial effects on performance. Studies should be conducted where the animals are exposed to commercial conditions, as the presence of natural stressors could allow a better evaluation of the efficacy of the anti-inflammatory agent as a growth promoter.

Multidrug-resistant and potentially pathogenic Enterobacteriaceae found in a tertiary hospital sewage in southeastern Brazil

Hospital sewage is considered an environment with the potential to favor the spread and increase of multidrug-resistant bacteria (MDR). The increase in antimicrobial resistance is one of the greatest global threats today. Therefore, this study aimed to evaluate the profile of antimicrobial susceptibility and virulence factors in Enterobacteriaceae isolated from the sewage of a tertiary hospital located in southeastern Brazil. For bacterial isolation, membrane filtering, serial dilution, and spread-plate techniques were used. The bacterial isolates were identified using the MALDI-TOF (matrix-assisted laser desorption ionization-time of flight) technique. Antimicrobial susceptibility profile was performed by disk-diffusion test. Virulence genes were screened by Polymerase Chain Reaction (PCR) and the hypermucoviscosity phenotype by string test. In total, 13 enterobacteria distributed in three species were identified (Klebsiella pneumoniae, Escherichia coli, and Citrobacter freundii) and 76.9% (n = 10) were classified as MDR. Two K. pneumoniae demonstrated the hypermucoviscosity phenotype. The virulence genes ycfM and entB were detected in all K. pneumoniae isolates (other genes found were fimH, mrkD, and kfu). The results indicated that the sewage from the analyzed hospital receives MDR bacteria and has the potential to contaminate and spread through the environment.

Genomic features of in vitro selected mutants of Escherichia coli with decreased susceptibility to tigecycline

The increase in multidrug-resistant bacteria has reached an alarming rate globally, making it necessary to understand the underlying mechanisms mediating resistance in order to discover new therapeutics. Tigecycline (TGC) is a last-resort antimicrobial agent for the treatment of serious infections caused by extensively drug-resistant Enterobacteriaceae. The TGC-resistant Escherichia coli mutants were obtained by exposing three different TGC-susceptible isolates belonging to ST131 (n=2) and ST405 (n=1) to increasing concentrations of TGC. The genetic alterations associated with reduced susceptibility to TGC were identified using whole genome sequencing. The fitness cost of TGC resistance acquisition, as well as incidence of cross-resistance, was also investigated. The TGC minimum inhibitory concentrations (MICs) of in vitro selected mutants were elevated 8 to 32 times compared with ancestral strains. Inactivating mutations (frameshift and nonsense) or amino acid substitutions were identified in genes encoding proteins with diverse functions, including AcrAB efflux pump or its regulators (lon and marR), Lipopolysaccharides (LPS) inner core biosynthesis enzymes (waaQ and eptB), ribosomal S9 protein (rpsI), and RNA polymerase β subunit. In most cases (but not all), acquisition of TGC resistance was associated with a fitness cost. While TGC resistance development was associated with cross-resistance to other members of the tetracycline family and chloramphenicol, hypersensitivity to nitrofurantoin was identified among heptose III-less LPS mutants. TGC resistance among the studied mutants was found to be multifactorial with extrusion by efflux transports being the most common mechanism. The LPS inner core biosynthesis pathway, as well as ribosomal S9 protein, could be additional targets for TGC resistance.

The cyclic octapeptide antibiotic argyrin B inhibits translation by trapping EF-G on the ribosome during translocation

Argyrins are a family of naturally produced octapeptides that display promising antimicrobial activity against Pseudomonas aeruginosa. Argyrin B (ArgB) has been shown to interact with an elongated form of the translation elongation factor G (EF-G), leading to the suggestion that argyrins inhibit protein synthesis by interfering with EF-G binding to the ribosome. Here, using a combination of cryo-electron microscopy (cryo-EM) and single-molecule fluorescence resonance energy transfer (smFRET), we demonstrate that rather than interfering with ribosome binding, ArgB rapidly and specifically binds EF-G on the ribosome to inhibit intermediate steps of the translocation mechanism. Our data support that ArgB inhibits conformational changes within EF-G after GTP hydrolysis required for translocation and factor dissociation, analogous to the mechanism of fusidic acid, a chemically distinct antibiotic that binds a different region of EF-G. These findings shed light on the mechanism of action of the argyrin-class antibiotics on protein synthesis as well as the nature and importance of rate-limiting, intramolecular conformational events within the EF-G-bound ribosome during late-steps of translocation.

Genetic, antimicrobial resistance profile andmortality rates of Acinetobacter baumanniiinfection in Brazil: A systematic reviewMirian.

The increase of multidrug-resistant bacteria - including Acinetobacter baumannii (A. baumannii) - has been reported globally. The aim of this systematic review was to determine the risk factors of A. baumannii infection, its resistance profile, reservoirs and mortality rates in Brazil. Data from over 3,000 patients were included. Results suggested that A. baumannii is widely transmitted in Brazil and the endemic clones ST1, ST15, ST 25, ST79, ST162 and ST730 were the most reported; also, blaOXA23, blaOXA51 and blaOXA143 were common resistant genes. The risk factors for A. baumannii infection included the procedure of using invasive devices, previous antibiotic therapy, hemodialysis, comorbidities and higher scores on the Sequential Organ Failure Assessment (SOFA). Two out of five studies identified multidrug resistant A. baumannii to polymyxin. Mortality rates varied between 43.7% to 81%, except for the ST25 strain in which there was a 100% mortality rate. Mortality was associated with sepsis, respiratory infection, septic shock, old age (>60 years) and administration of norepinephrine. Nonetheless, this review highlights the need for more data on A. baumannii infection across Brazil to support public policies aiming to control and prevent the dissemination of this bacteria.

Prevalence and characterisation of carbapenemase encoding genes in multidrug-resistant Gram-negative bacilli.

Emerging worldwide in the past decade, there has been a significant increase in multidrug-resistant bacteria from serious nosocomial infections, especially carbapenemase-producing Gram-negative bacilli that have emerged worldwide. The objective of this study is to investigate carbapenem resistance in Gram-negative bacilli bacteria using phenotypic detection, antimicrobial resistance profiles and genotypic characterisation methods. 200 Gram-negative bacilli isolates were collected from different clinical specimens. All clinical samples were exposed to isolation and identification of significant pathogens applying bacteriological examination and an automated Vitek-2 system. The isolates were subjected to susceptibility tests by the Vitek-2 automated system and those isolates that were resistant to beta-lactam drugs, including carbapenems, third-generation cephalosporines or cefoxitin, were selected for phenotyping using Carba plus disc system assay for detection of carbapenemase-producing isolates. These isolates were further confirmed by molecular detection. PCR was used for the detection carbapenem-resistant genes (OXA-48, IMP, NDM, VIM, and KPC). 110 (55%) of 200 Gram-negative bacilli were identified as beta-lactam-resistant isolates. The frequency of carbapenem-resistant isolates was calculated to be 30.9% (n = 34/110). A collection totalling 65/110 (59%) isolates were identified as carbapenemase producers by phenotypic method. Moreover, among the 65 carbapenemase-producing Gram-negative isolates with a positive phenotype-based result, 30 (46%), 20 (30%) and 18 (27%) isolates were positive for OXA-48, KPC and MBL enzymes, respectively, as well as the production of 27% of AmpC with porin loss. Tigecycline was the most effective antibiotic that affected 70% of MDR isolates, but high rates of resistance were detected to other tested antimicrobials. Of interest, a high incidence of MDR, XDR and PDR profiles were observed among all carbapenemase-producing isolates. 36% (24/65) of the tested isolates were MDR to 3 to 5 antimicrobial classes. 29% (17/65) of the recovered isolates were XDR to 6 to 7 antimicrobial classes. Alarmingly, 24% (16/65) of isolates displayed PDR to all the tested 8 antimicrobial classes. Genotype assay, including 53 phenotypically confirmed carbapenemase-producing isolates of Gram-negative bacilli, found 51(96%) isolates were harbouring one or more genes. The most common carbapenemase gene was bla NDM 83% (44/53) followed by bla OXA-48 75% (40/53), bla VIM 49% (26/53) and bla IMP 43% (23/53), while the gene bla KPC was least frequent 7% (4/53). 92% (46/51) of isolates were involved in the production of more than one carbapenemase gene. This study demonstrated the emergence of carbapenemase-producing Gram-negative pathogens implicated in healthcare-related infections. Accurate identification of carbapenem-resistant bacterial pathogens is essential for patient treatment, as well as the development of appropriate contamination control measures to limit the rapid spread of pathogens. Tigecycline exhibited potent antimicrobial activity against MDR, XDR and PDR-producing strains that establish a threatening alert which indicates the complex therapy of infections caused by these pathogens.

Synthesis of Chitosan-Coated Silver Nanoparticle Bioconjugates and Their Antimicrobial Activity against Multidrug-Resistant Bacteria

The increase in multidrug-resistant bacteria represents a true challenge in the pharmaceutical and biomedical fields. For this reason, research on the development of new potential antibacterial strategies is essential. Here, we describe the development of a green system for the synthesis of silver nanoparticles (AgNPs) bioconjugated with chitosan. We optimized a Prunus cerasus leaf extract as a source of silver and its conversion to chitosan–silver bioconjugates (CH-AgNPs). The AgNPs and CH-AgNPs were characterized using transmission electron microscopy (TEM), dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FT-IR), ultraviolet–visible spectroscopy (UV–Vis), and zeta potential measurement (Z-potential). The cytotoxic activity of AgNPs and CH-AgNPs was assessed on Vero cells using the 3-[4.5-dimethylthiazol-2-yl]-2.5-diphenyltetrazolium bromide (MTT) cell proliferation assay. The antibacterial activity of AgNPs and CH-AgNPs synthesized using the green system was determined using the broth microdilution method. We evaluated the antimicrobial activity against standard ATCC and clinically isolated multisensitive (MS) and multidrug-resistant bacteria (MDR) Escherichia coli (E. coli), Enterococcus faecalis (E. faecalis), Klebsiella pneumonia (K. pneumoniae), and Staphylococcus aureus (S. aureus), using minimum inhibitory concentration (MIC) assays and the broth dilution method. The results of the antibacterial studies demonstrate that the silver chitosan bioconjugates were able to inhibit the growth of MDR strains more effectively than silver nanoparticles alone, with reduced cellular toxicity. These nanoparticles were stable in solution and had wide-spectrum antibacterial activity. The synthesis of silver and silver chitosan bioconjugates from Prunus cerasus leaf extracts may therefore serve as a simple, ecofriendly, noncytotoxic, economical, reliable, and safe method to produce antimicrobial compounds with low cytotoxicity.

Hidden suppressive interactions are common in higher-order drug combinations

SummaryThe rapid increase of multi-drug resistant bacteria has led to a greater emphasis on multi-drug combination treatments. However, some combinations can be suppressive—that is, bacteria grow faster in some drug combinations than when treated with a single drug. Typically, when studying interactions, the overall effect of the combination is only compared with the single-drug effects. However, doing so could miss “hidden” cases of suppression, which occur when the highest order is suppressive compared with a lower-order combination but not to a single drug. We examined an extensive dataset of 5-drug combinations and all lower-order—single, 2-, 3-, and 4-drug—combinations. We found that a majority of all combinations—54%—contain hidden suppression. Examining hidden interactions is critical to understanding the architecture of higher-order interactions and can substantially affect our understanding and predictions of the evolution of antibiotic resistance under multi-drug treatments.

Feasibility of an inhaled antibiotic/adjuvant dry powder combination using an experimental design approach

The global increase of multidrug resistant bacteria and the lack of new classes of antibiotic especially those targeting Gram-negative pathogens are leaving the clinicians disarmed to treat numerous bacterial infections. Recently, the design of adjuvants able to enhance antibiotics activities appears to be one of the most promising investigated solutions to circumvent this problem. In this context, we have recently identified a new polyamino-isoprenyl derivative NV716 able to potentiate, at a very low concentration the activity of doxycycline against resistant P. aeruginosa bacterial strains by increasing its intracellular concentration. In this study we will report an experimental protocol to optimize a dry powder for inhalation ensuring the simultaneous delivery of an antibiotic (doxycycline) and an adjuvant (the polyaminoisoprenyl derivative NV716 since aerosol therapy could allow a rapid drug administration and target the respiratory system by avoiding the first pass effect and minimizing undesirable systemic effects. Thus, an experimental design was carried out permitting to identify the influence of several factors on the aerosolization efficiency of our combination and allowing us to find the right composition and manufacture leading to the best optimization of the simultaneous delivery of the two compounds in the form of an inhalable powder. More precisely, the powders of the two active ingredients were prepared by freeze drying and their aerosolization was improved by the addition of carrier particles of lactose inhalation grade. Under these conditions, the best formulation was defined by combining the optimal factors leading to the best aerodynamic properties’ values (the lowest MMAD (Mass Median Aerodynamic Diameter) and the highest FPF (Fraction of Fine Particles)) without even using sophisticated engineering techniques. Finally, our results suggest that these molecules could be successfully delivered at the requested concentration in the lungs and then able to decrease drug consumption as well as increase treatment efficacy.

The Importance of Early Management of Severe Biliary Infection: Current Concepts

BackgroundThe incidence of biliary infections is rising worldwide and has become one of the main reasons for emergency admissions.MethodsThis is a narrative review of the literature emphasizing news concepts related to the early management of biliary diseases.ResultsThe bacteriology is frequently polymicrobial, with a progressive increase of multidrug resistant bacteria. The form of presentation is variable, and the mortality rate may reach 20%. When cholecystitis or cholangitis is suspected, ultrasound is the gold standard imaging test. Depending on the severity of presentation, local resistances, and risk factors for multiresistant organisms, the most appropriate empirical antibiotic treatment must be initiated. In acute cholecystitis, cholecystectomy plays the main therapeutic role. In patients not suitable for surgery, percutaneous cholecystostomy is a valid alternative for source control. Treatment of severe cholangitis is based on the drainage of the bile duct and antibiotic therapy.ConclusionsBiliary infections are serious conditions that can lead to sepsis and death. The introduction of new internationally accepted guidelines, based on clinical presentation, laboratory tests, and imaging, provides a platform for their timely diagnosis and management. Early severity assessment, initiation of intravenous antibiotics, and source control are fundamental to improving morbidity and mortality.

Afyonkarahisar Sağlık Bilimleri Üniversitesi Sağlık Uygulama ve Araştırma Merkezi Yatan Hasta Kümülatif Antibiyotik Duyarlılık Raporu (2020)

Objective: Broad-spectrum antibiotics used in empirical treatment lead to an increase in multidrug-resistant bacteria in intensive care units and hospital wards. Cumulative antibiotic susceptibility reports can guide the correct selection of empirical therapy and development of antibiotic resistance policies. In this study, we aimed to prepare a one-year inpatient cumulative antibiotic susceptibility report for our hospital. Method: Identification of bacteria and antibiotic susceptibility tests were performed with the automated VITEK 2 (bioMérieux, France) system and antibiogram results were evaluated according to the recommendations of The European Committee on Antimicrobial Susceptibility Testing (EUCAST, 2021). The cumulative antibiotic susceptibility report has been prepared according to the criteria in the Analysis and Presentation of Cumulative Antimicrobial Susceptibility Test Data (CLSI 2014, M39-A4). Results: In this study, 1490 isolates were analysed. Vancomycin, teicoplanin, linezolid, and tigecycline were effective against gram positive agents. While tigecycline and cefuroxime were effective against enteric Escherichia coli isolates, nitrofurantoin and meropenem can be used in empirical treatment in urinary enterics. It has been observed that the most effective antibiotics against Proteus mirabilis were meropenem and amikacin. It was found that among the enteric and urinary enteric bacteria, there was no antibiotic option to be preferred in empirical treatment against Klebsiella pneumoniae isolates. Tigecycline was the most effective antibiotic against Acinetobacter baumannii isolates, whereas tobramycin was the most effective antibiotic against Pseudomonas aeruginosa isolates. Conclusion: Empirical treatment options for gram-negative and gram-positive bacteria are limited, and we believe that close monitoring of cumulative antibiotic reports will improve and reduce antibiotic resistance rates.

Comparative antioxidant and antimicrobial properties of Lentinula edodes Donko and Koshin varieties against priority multidrug-resistant pathogens

The problematic increase in multidrug-resistant bacteria translates into the urgent need to discover novel and effective antimicrobial substances. Herein, mushrooms could be a promising alternative of natural source of new antimicrobials. The present work aimed to compare the phytochemical composition and antimicrobial activity of methanol and aqueous crude extracts of Lentinula edodes var. Koshin and Donko. Disk diffusion method was used to screen the antimicrobial activity and to assess the synergistic effect of the mushroom extracts. Microdilution method was used to determine the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC). Phytochemical characterization of mushrooms extracts was achieved by analysis of total phenols, ortho-diphenols content and its antioxidant activity. The results noticed a positive relation between phenolic compounds content, antioxidant activity, and antimicrobial capacity of the mushroom's extracts. The L. edodes var. Koshin aqueous extracts, which contained the highest amount of total phenolic compounds, exhibited the highest scavenging capacity of ABTS which, in turns, exhibited the highest antimicrobial efficacy in inhibiting the growth of methicillin-resistant Staphylococcus aureus. Moreover, the combination between mushrooms extracts and commercial antibiotics showed favorable synergistic effects against tested bacteria. These results suggest that L. edodes var. Koshin may represent an important and valuable therapeutic source of compounds to be used against multidrug-resistant bacteria.

Enhanced Antibacterial Activity of Silver Nanoparticles Combined with Hydrogen Peroxide Against Multidrug-Resistant Pathogens Isolated from Dairy Farms and Beef Slaughterhouses in Egypt.

PurposeThe last few decades have witnessed a rapid and global increase in multidrug-resistant bacteria (MDR) emergence.MethodsThe aim of the current study is to isolate the most common MDR bacteria from dairy farms and beef slaughterhouses followed by evaluation of their antimicrobial resistance pattern and assessment of the antibacterial activity of AgNPs-H2O2 as an alternative to conventional antibiotics. In this regard, 200 samples were collected from two dairy farms and one beef slaughterhouse located in Dakhliya Governorate, Egypt.ResultsInterestingly, out of 120 collected samples from dairy farms, the prevalence of the isolated strains was 26.7, 23.3, 21.7, 16.7, and 11.7% for S. typhimurium, E. coli O157:H7, L. monocytogenes, K. pneumoniae and P. aeruginosa, respectively. Meanwhile, the overall prevalence was 30, 25, 22.5, 17.5, and 5% for E. coli O157:H7, L. monocytogenes, S. typhimurium, P. aeruginosa, and K. pneumoniae, respectively, for the 80 samples collected from a beef slaughterhouse. The antimicrobial susceptibility pattern elucidated that all isolated strains exhibited resistance to at least four of the tested antimicrobials, with multiple-antibiotic resistance index values (MAR) ranging between 0.44 and 0.88. Furthermore, the commercial AgNPs-H2O2 product was characterized by transmission electron microscopy (TEM) and zeta potential that showed spherical particles with a surface charge of −0.192 mV. The antimicrobial activity of synergized nano-silver (AgNP) with H2O2 product toward MDR strains was assessed via measuring minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and time-kill curve.ConclusionThe present data report high prevalence rates of MDR pathogens in dairy farms and abattoirs. More importantly, AgNPs-H2O2 exerted broad-spectrum bactericidal activity toward MDR bacterial strains, suggesting their promising usage as safe, ecofriendly, cost-effective antibacterial agents. To our knowledge, this study is a pioneer in investigating the potential alternative antimicrobial role of silver nanoparticles for control of multiple drug-resistant pathogens in Egypt.

Hop Extract: An Efficacious Antimicrobial and Anti-biofilm Agent Against Multidrug-Resistant Staphylococci Strains and Cutibacterium acnes.

Bacteria belonging to Staphylococcus genus, in particular methicillin-resistant Staphylococcus aureus and multidrug-resistant Staphylococcus epidermidis, together with Cutibacterium acnes are the main strains involved in skin disease. The increase in multidrug-resistant bacteria has revived attention on natural compounds as alternative agents for the treatment management. Among these, hop extract, a hydroalcoholic solution obtained from experimental crops of Humulus lupulus L. variety cascade (hop), displays diverse biological properties including an antimicrobial one. The aim of this study was to evaluate the antimicrobial activity and the capacity to inhibit the biofilm formation of a characterized hop extract against S. aureus and S. epidermidis multidrug-resistant strains and against a C. acnes strain. The hop extract was characterized by (i) phytochemical analysis through a reversed-phase high-performance liquid chromatography (HPLC)–fluorimetric method, (ii) biocompatibility test with Artemia salina L., (iii) cytotoxicity against two cell lines, (iv) docking analysis, and (v) antimicrobial and antibiofilm activities by detection of zones inhibition, minimal inhibitory concentrations (MICs), biomass quantification, and cell viability. The hop extract was biocompatible and non-cytotoxic at all tested concentrations. HPLC analysis revealed significant levels of gallic acid, resveratrol, and rutin. This last compound was the most representative displaying a high affinity against PBP2a and KAS III (Ki values in the submicromolar range). The characterized hop extract showed a good antimicrobial action with MICs ranging from 1 to 16 μg/mL and was able to inhibit the biofilm formation of all tested strains, except for two S. aureus strains. The biofilm formed in presence of the hop extract was significantly reduced in most cases, even when present at a concentration of 1/4 MIC. The live/dead images showed a remarkable inhibition in the biofilm formation by hop extract with a weak killing action. Overall, the tested hop extract is a good candidate to further explore for its use in the prevention of infection particularly, by multidrug-resistant Gram-positive pathogens.

Antimicrobial use for treatment of healthcare-associated infections and bacterial resistance in a reference neonatal unit

ObjectiveThe use of broad-spectrum antimicrobials, such as third and fourth-generation, are responsible for emergence of multidrug-resistant microorganisms in neonatal units. Furthermore, antimicrobial daily doses are not standardized in neonatology. This study aimed to investigate the association between the use of antimicrobial broad spectrum to bacterial sensitivity profile in a referral unit of neonatal progressive care. MethodsThis is a cohort study conducted in a referral neonatal progressive care unit from January 2008 to December 2016. The data of all hospitalized neonates was collected daily. The infection criteria used were the standardized national criteria, based on definitions of Center for Diseases Control and Prevention. In this study, the use of antimicrobials was evaluated as antimicrobial-day (ATM-day) and the ratio of multidrug-resistant microorganisms per 1000 ATM-day of broad spectrum was also calculated. The study was approved by the Institutional Review Board of the Universidade Federal de Minas Gerais (ETIC 312/08 e CAAE 58973616.2.0000.5149). ResultsFrom 2008 to 2016, 2751 neonates were hospitalized, corresponding to 60,656 patient-days. The ratio of multidrug-resistant microorganisms per 1000 ATM-day of broad spectrum was 1,3 in the first period and 4,3 in the second period (p=0,005). ConclusionIt was observed that use of broad-spectrum antimicrobials, especially those with coverage for Gram-negative bacteria, was associated with an increase of multidrug-resistant bacteria.