Multidrug Resistant Bacteria Bacteria Research Articles

Enhancing antibacterial activity against multi-drug resistant wound bacteria: Incorporating multiple nanoparticles into chitosan-based nanofibrous dressings for effective wound regeneration

Wound infection continues to pose a significant challenge in the field of wound healing. Multi-drug resistant bacteria (MDR) make it even more complicated. Therefore, there is a pressing need to fabricate wound dressings with enhanced antimicrobial activity, particularly against MDR strains. In this study, we aimed to incorporate three antimicrobial nanoparticles into a chitosan-based nanofibrous mat (CS) and assess their antimicrobial activity against MDR bacteria. We fabricated CS mats incorporated with silver nanoparticles (CS-nAg), CuO nanoparticles (CS-nCuO), ZnO nanoparticles (CS-nZnO), a combination of Ag and CuO nanoparticles (CS-nAC), and a combination of Ag, CuO, and ZnO nanoparticles (CS-nACZ). The antimicrobial activity of these mats against MDR clinical isolates of four common wound bacteria including Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, and Acinetobacter baumannii were investigated. Each strain was tested using 10 isolates. According to in-vitro study, mats incorporated with a single type of nanoparticle demonstrated antimicrobial activity against certain isolates of P. aeruginosa, S. aureus, and E. coli. However, the antimicrobial activity was enhanced when multiple types of nanoparticles were combined (CS-nAC and CS-nACZ). Notably, CS-nACZ was the only mat that demonstrated antimicrobial activity against A. baumannii. In addition to its superior antimicrobial activity, CS-nACZ did not exhibit cytotoxicity towards fibroblasts. In an animal study using an infected wound rat model, the CS-nACZ mat demonstrated superior antimicrobial activity and excellent wound regeneration ability. These results suggest that the use of multiple nanoparticles in CS based wound dressing can lead to enhanced antimicrobial effects and effective wound regeneration.

Origin and Clinical Impact of Early Multidrug-Resistant (MDR) Contamination in Patients Undergoing Pancreaticoduodenectomy

Introduction: Infections caused by multidrug-resistant bacteria (MDR) occur more frequently after pancreaticoduodenectomy (PD) compared to other abdominal surgeries, and infective complications represent a major determinant of postoperative morbidity following PD. Preoperative biliary stent (PBS) placement often leads to biliary contamination, which plays a significant role in postoperative infections. The aim of this study is to evaluate the impact of MDR contamination on short-term postoperative outcomes in patients undergoing PD and to evaluate the relationship between MDR bacteria, PBS, and bile contamination. Methods: This is a retrospective study based on a prospectively maintained database including 825 consecutive patients who underwent pancreaticoduodenectomies (PDs). All procedures were performed by experienced pancreatic surgeons at a high-volume center and the patients were managed according to the same perioperative enhanced recovery protocol. Results: MDR bacteria were present in 17.5% of bile cultures, exclusively within the stented group. At the multivariate analysis, the development of major postoperative complications (MPC) was correlated with the presence of MDR bacteria in the bile (OR 1.66, 95% CI: 1.1–2.52; p = 0.02). MDR bacteria were detected early in the surgical drainage in 144 out of 825 patients (12.1%), with 72.2% having a previous biliary stent placement and 27.8% without stents (p < 0.001). Moreover, the development of an MPC was associated with the presence of MDR bacteria in the drainage (OR = 1.81, 95% CI: 1.21–2.73, p = 0.0042). Conclusions: We demonstrated that MDR contamination worsens the short-term outcomes of patients undergoing PDs. Specifically, when MDR bacteria are present in both the bile and drainage, there is a statistically significant increase in the incidence of major postoperative complications (MPC). Our data suggest that the majority of MDR surgical site infections stem from biliary contamination resulting from the placement of a preoperative biliary stent (PBS).

Mapping pathogenic bacteria resistance against common antibiotics and their potential susceptibility to methylated white kidney bean protein.

As antibiotics cannot inhibit multidrug-resistant bacteria (MDR), continuous research is mandatory to find other antibacterials from natural resources. Native legume proteins and their modified forms exhibited broad spectra of high antimicrobial activities. Sixteen bacterial isolates were mapped for antibiotic resistance, showing resistance in the range of (58-92%) and (42-92%) in the case of the Gram-negative and Gram-positive bacteria, respectively. White native Phaseolus vulgaris protein (NPP) was isolated from the seeds and methylated (MPP). The MIC range of MPP against 7 MDR bacteria was 10-25 times lower than NPP and could (1 MIC) considerably inhibit their 24h liquid growth. MPP showed higher antibacterial effectiveness than Gentamycin, the most effective antibiotic against Gram-positive bacteria and the second most effective against Gram-negative bacteria. However, MPP recorded MICs against the seven studied MDR bacteria in the 1-20µg/mL range, the same for Gentamycin. The combination of Gentamycin and MPP produced synergistic effects against the seven bacteria studied, as confirmed by the Transmission Electron Microscopic images. The antimicrobial activity of MPP against the seven MDR bacteria remained stable after two years of cold storage at 8-10°C as contrasted to Gentamycin, which lost 20-72% of its antimicrobial effectiveness.

Role of multidrug-resistant bacteria in weaning from invasive mechanical ventilation

BackgroundAlthough multidrug-resistant bacteria (MDR) are common in patients undergoing prolonged weaning, there is little data on their impact on weaning and patient outcomes.MethodsThis is a retrospective analysis of consecutive patients who underwent prolonged weaning and were at a university weaning centre from January 2018 to December 2020. The influence of MDR colonisation and infection on weaning success (category 3a and 3b), successful prolonged weaning from invasive mechanical ventilation (IMV) with or without the need for non-invasive ventilation (NIV) compared with category 3c (weaning failure 3cI or death 3cII) was investigated. The pathogen groups considered were: multidrug-resistant gram-negative bacteria (MDRGN), methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus spp. (VRE).ResultsA total of 206 patients were studied, of whom 91 (44.2%) showed evidence of MDR bacteria (32% VRE, 1.5% MRSA and 16% MDRGN), with 25 patients also meeting the criteria for MDR infection. 70.9% of the 206 patients were successfully weaned from IMV, 8.7% died. In 72.2% of cases, nosocomial pneumonia and other infections were the main cause of death. Patients with evidence of MDR (infection and colonisation) had a higher incidence of weaning failure than those without evidence of MDR (48% vs. 34.8% vs. 21.7%). In multivariate analyses, MDR infection (OR 4.9, p = 0.004) was an independent risk factor for weaning failure, along with male sex (OR 2.3, p = 0.025), Charlson Comorbidity Index (OR 1.2, p = 0.027), pH (OR 2.7, p < 0.001) and duration of IMV before admission (OR 1.01, p < 0.001). In addition, MDR infection was the only independent risk factor for death (category 3cII), (OR 6.66, p = 0.007).ConclusionPatients with MDR infection are significantly more likely to die during the weaning process. There is an urgent need to develop non-antibiotic approaches for the prevention and treatment of MDR infections as well as clinical research on antibiotic stewardship in prolonged weaning as well as in ICUs.

Prevalence and risk factors associated with drug resistant bacteria in neonatal and pediatric intensive care units: A retrospective study in Saudi Arabia.

Successful empirical antibiotic therapy for infected patients with multi drug resistant bacteria (MDR) can be challenging task in various healthcare settings, including neonatal and pediatric intensive care units (NICU and PICU, respectively), unless an up-to-date comprehensive local antibiogram data is available. Thus, this project aimed to investigate the prevalence of MDR among PICU and NICU patients as well as the identification of risk factors associated with recovered MDR bacteria. This was a retrospective study of PICU and NICU patients admitted with bacterial infection of MDR organisms between October 2020 and May 2021. Frequency distribution, Chi-square test were applied to verify the significance differences among subgroups and to identify risk factor associated with each group. About 36.4% of recruited patients were neonates, while the remaining percentage (63.6%) were pediatric. The most predominant site of infection among these patients were revealed as urinary tract (35%), followed by bloodstream (20.0%), wound/skin (12.9%) and respiratory system (11.4%). Methicillin-resistant Staphylococcus aureus (MRSA) was identified as the most common microbe across these sites of infections (30.7%), followed by Escherichia coli (25.0%), Klebsiella pneumoniae (22.9%) and Serratia (10.0%). High mortality rate was significantly associated with patients who were on mechanical ventilators (28.9%, OR 5.5; 95% CI), followed by patients had invasive operation (27.5%, OR, 8.04; 95% CI) and those who required a total parental nutrition (TPN) since almost one-half of these cases have (46.2%) died. In addition, mortality rate was relatively higher among patients infected with species of Serratia (28.6%) and Enterobacter (20.0%). These data highlighted that MRSA was the main MDR bacteria isolated from PICU and NICU followed by gram-negative bacteria, which were associated with high mortality rate. Therefore, infection control measures and continuous monitoring of emerging MDR bacteria should be applied to limit the bacterial infections in NICU and PICU patients.

ICU-Acquired Colonization and Infection Related to Multidrug-Resistant Bacteria in COVID-19 Patients: A Narrative Review.

A large proportion of ICU-acquired infections are related to multidrug-resistant bacteria (MDR). Infections caused by these bacteria are associated with increased mortality, and prolonged duration of mechanical ventilation and ICU stay. The aim of this narrative review is to report on the association between COVID-19 and ICU-acquired colonization or infection related to MDR bacteria. Although a huge amount of literature is available on COVID-19 and MDR bacteria, only a few clinical trials have properly evaluated the association between them using a non-COVID-19 control group and accurate design and statistical methods. The results of these studies suggest that COVID-19 patients are at a similar risk of ICU-acquired MDR colonization compared to non-COVID-19 controls. However, a higher risk of ICU-acquired infection related to MDR bacteria has been reported in several studies, mainly ventilator-associated pneumonia and bloodstream infection. Several potential explanations could be provided for the high incidence of ICU-acquired infections related to MDR. Immunomodulatory treatments, such as corticosteroids, JAK2 inhibitors, and IL-6 receptor antagonist, might play a role in the pathogenesis of these infections. Additionally, a longer stay in the ICU was reported in COVID-19 patients, resulting in higher exposure to well-known risk factors for ICU-acquired MDR infections, such as invasive procedures and antimicrobial treatment. Another possible explanation is the surge during successive COVID-19 waves, with excessive workload and low compliance with preventive measures. Further studies should evaluate the evolution of the incidence of ICU-acquired infections related to MDR bacteria, given the change in COVID-19 patient profiles. A better understanding of the immune status of critically ill COVID-19 patients is required to move to personalized treatment and reduce the risk of ICU-acquired infections. The role of specific preventive measures, such as targeted immunomodulation, should be investigated.

Covid-19 with Methicillin-Resistant Staphylococcus Aureus: Based on Two Cases in Diponegoro National Hospital

Background: Coronavirus disease 19 (COVID-19) has become pandemic in the world with a board spectrum of clinical presentation. Secondary infection of methicillin-resistant staphylococcus aureus (MRSA) affects morbidity and mortality in patients with COVID-19.Case: We reported two COVID-19 patients with MRSA hospitalized in intensive care unit (ICU) of Diponegoro National Hospital. The first patient was 61-year-old woman that was referred from another hospital with confirmed COVID-19 infection and acute respiratory distress syndrome and had been intubated. Diabetes mellitus and hypertension were known as comorbid. On day 4 of treatment in ICU, blood culture results showed MRSA infection and antibiotic therapy was replaced with Vancomycin. The patient had clinical improvement and was discharge from the hospital on the 36th day of treatment. The second one was 51-year-old woman admitted with probable COVID-19, type II Diabetes Mellitus and hypertension. On day 9th the patient was transferred to ICU because of respiratory failure, blood culture on day 15th show a result of MRSA and antibiotic therapy was replaced with vancomycin. She declined intubation procedures and died on day 20.Discussion: Antibiotic resistance has become one of the important things in infection management in the world. Multidrug-resistant bacteria (MDR) cause treatment failure which increases the risk of death and cost. MRSA has become one of the most important MDR bacteria during the last decade causing severe infections in health facilities. Complications of bacterial infection in COVID-19, especially bacteremia increases the severity and mortality of severe patients.Conclusion: Coinfection of MRSA in COVID-19 patients can affect the clinical outcome. One of important risk factor is history or prolonged hospitalized. Other factors are comorbidity of the patient and appropriate therapy is needed to reduce mortality in Intensive Care Unit.

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.

Cellular modes of action of the methanol extract from the aerial parts of Psychotria sycophylla (K.Schum.) Petit (Rubiaceae) against multidrug-resistant bacteria

Background: Infectious diseases caused by multidrug-resistant bacteria (MDR) remain a global health issue. The population uses several plants from the Cameroonian pharmacopeia to treat bacterial infections. The methanol extract from the aerial parts of Psychotria sycophylla (K.Schum.) Petit (Rubiaceae) (PSA) previously showed antibacterial activities against MDR bacteria. In the present study, the antibacterial activities of PSA were determined in the presence of an efflux pump inhibitor (EPI), phenylalanine-arginine β-naphthylamide (PAβN). The effects of PSA on the bacterial membrane and its ability to inhibit the bacterial biofilm were also assessed. Methods: The evaluation of antibacterial activity of PSA in the presence of PAβN was evaluated using the microdilution method. The modification of the bacterial membrane permeability as well as the inhibition of biofilm were evaluated using spectrophotometric methods. Results: When tested with PAβN, the inhibitory effects of PSA increased vis à vis all the tested bacteria. PSA also destroyed the bacterial membrane and showed significant inhibition of biofilms of Escherichia coli AG102 strain. Conclusion: The reported data provide complementary information on the antibacterial effect of Psychotria sycophylla and might be helpful in formulating a phytomedicine to combat infections due to multidrug-resistant bacteria. Keywords: Bacteria; modes of action; multidrug resistance; Psychotria sycophylla; Rubiaceae.

Photodynamic inactivation of multidrug-resistant bacteria in wastewater effluent using green phytochemicals as a natural photosensitizer

The control of multidrug-resistant bacteria (MDRB) is a great challenge in the 21st century. Photodynamic treatment (PDT) is one of the promising approaches to control MDRB. In the process, powerful oxidants such as reactive oxygen species (ROS) are produced, which cause cytotoxic damage and cell death of bacteria. This study examined a new and environment-friendly strategy for the photodynamic inactivation of two MDRB (Escherichia coli and Staphylococcus aureus) and total coliform (TC) in wastewater effluent using two phytochemicals, pyrogallol (PGL) and terpinolene (TPN), along with white and blue light-emitting diode (LED) light. Fourier-transform infrared spectroscopy (FTIR) of the phytochemicals confirmed the presence of different phenolic and aromatic compounds, which can enhance the generation of ROS alongside inactivating the bacterial cells. In the PDT process, white LED light was more active in controlling MDRB than blue LED light. After 80 min irradiation with white LED light (17 mW/cm2), the MDRB bacteria were eradicated completely at a minimum inhibitory concentration (MIC) dose (0.156 mg/mL for E. coli and 0.078 mg/mL for S. aureus) of PGL. In addition, light intensity was an important parameter in photodynamic disinfection. The TC in the secondary effluent was inactivated completely by both phytochemicals after 60 min of exposure to white LED light with an intensity of 80 mW/cm2. The photosensitizing activity of phytochemicals was analyzed by a bactericidal and imidazole-RNO assay. These assays showed that PGL contributed to the generation of •OH radicals, whereas TPN produced 1O2 in the PDT process. Transmission electron microscopy (TEM) confirmed bacterial cell disruption after treatment. Overall, PDT using the phytochemicals as PS is a sustainable approach to control the MDRB and TC in wastewater successfully.

Tigecycline susceptibility among multi-drug resistant bacteria: A 7-year retrospective study

The emergence and spread of multidrug-resistant bacteria (MDR) are major public health issues worldwide. The objective of this study is to evaluate the microbiological efficacy of tigecycline against multi-drug-resistant bacteria and to explore its potential place in clinical practice. A retrospective study was carried out over 7 years, from January 2015 to December 2021, at the Avicenne Military Hospital. Were collected all bacteriological samples received for diagnostic purposes at the microbiology laboratory. Tigecycline susceptibility was tested among 846 isolates among the 4293 isolates during the study period. The overall frequency of MDR bacteria was of 14,3%. 60% of the MDR bacteria isolated were susceptible, 35% were declared resistant and 5% were declared intermediate. Co-resistance levels in MDR bacteria are high. Tigecycline remained active in vitro on most of the MDR bacteria tested. The susceptibility rates for tigecycline found were respectively 76%, 57%, and 34%, for the ESBL Enterobacteriaceae strains, the CPEs, and the multi-drug resistant Acinetobacter baumanii strains. In this study, the MDR bacteria isolated showed overall satisfying susceptibility rates to tigecycline.

Synthesis and Evaluation of Antibacterial Activity of 1,2,3-Triazole and Ether Derivatives of Paeonol

Multi-drug-resistant bacteria (MDR) are the cause of different infections and diseases that have affected humanity for a long time, and have been an emerging global health problem that has led to increased morbidity and mortality. The growing emergence of MDR bacteria has underlined the need for development and discovery of new antibacterial compounds. In this context, a series of new paeonol 1,2,3-triazole and ether derivatives were synthesized using copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) reaction and nucleophilic substitution. Paeonol has been a natural product widely studied due to its many biological activities, as well as its derivatives. Three ether derivatives (two unpublished) and ten triazole derivatives (six unpublished) of paeonol were obtained, which were determined by nuclear magnetic resonance (NMR), Fourier transform infrared spectrometry (FTIR), Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR MS) and six of them by X-rays, which is the first study of this type presented for these compounds. All the synthesized compounds were evaluated as antibacterial agents against Staphylococcus aureus and Escherichia coli, obtaining a minimum inhibitory concentration (MIC) above 100 µg mL-1. The results showed that CuAAC and nucleophilic substitution were very useful to obtain new paeonol triazole and ether derivatives and the products were obtained in yields from 21.3 to 98.5%. The advantages of these reactions (high yield in most compounds, reaction time, low impurities) show that using the method to produce new derivatives is advisable thus assisting in the discovery of new potential bioactive compounds.

Hospital liquid waste contaminated with multidrug-resistant bacteria raises a public health hazard alert in Brazil.

The spread of multidrug-resistant bacteria (MDR) is a global concern because it poses a serious threat to public health. The inadequate handling of Health Services Waste (HSW) and, therefore, the incorrect disposal of infected liquids can cause contamination of the environment, the emergence of diseases caused by MDR bacteria, and the loss of the population's quality of life. The present study aimed to survey the bacteria and their antimicrobial resistance profiles, present in the liquid residues from infected surgeries performed in fiveyears, often discharged into the sewage network of a large tertiary hospital located in the city of Uberlândia, which is considered one of the main economic and demographic centers of Brazil. A systematic and retrospective survey of the medical records of patients who underwent infected surgeries from January 2015 to December 2019 was carried out at the referred hospital. The bacterial species were previously identified and characterized for the antimicrobial susceptibility profile by the VITEK 2 automated system (bioMérieux, Brazil). In the evaluated period, 1658 infected surgeries were performed and the results showed 661 bacterial strains distributed in 48 different species, being Staphylococcus aureus the most prevalent species. The vast majority (85.6%) showed some type of antimicrobial resistance among these strains, with more than half (54.6%) being MDR. The results of this work raise an alert and concern for the risks to the environment and public health by dumping these infected liquid wastes directly into the sewage system without proper prior decontamination.

Surveillance of antimicrobial resistant bacteria in flies (Diptera) in Rio de Janeiro city

Antimicrobial-resistant bacteria were isolated from muscoid dipterans collected at five different areas of Rio de Janeiro city, in proximity to hospitals. Extracts obtained by maceration of flies were diluted and used as inocula for different culture media, with or without antibiotic (ceftriaxone 1 mg/L) supplementation. Purified isolates were submitted to antimicrobial susceptibility testing (AST). Bacterial identification was performed by MALDI TOF Microflex LT (Bruker Daltonics). A total of 197 bacterial strains were obtained from 117 dipterous muscoids. Forty-two flies (35.9%) carried bacteria resistant to at least one antimicrobial, while 7 insects (5.9%) carried multidrug-resistant bacteria (MDR), which were all members of the family Enterobacteriaceae. Among 10 MDR bacteria (5%), 5 strains (2,5%) were positive by PCR for one or more of the following antibiotic resistance genes: aac(6’)-Ib, blaTEM-1, blaCTX-M-15, blaKPC-2 and blaNDM-1. Analysis of variance (ANOVA) and cluster analysis compared the number of resistant isolates per collection point and showed that a single location was statistically different from the others with regard to resistance. Although there are still no criteria to determine the environmental contamination by resistant bacteria the fact that they have been isolated from flies is an indication of a disseminated contamination. As such, these insects may be useful in monitoring programs of antibiotic resistance in non-hospital environments, where they could function as sentinels.

Biosynthesis of silver nano-drug using Juniperus excelsa and its synergistic antibacterial activity against multidrug-resistant bacteria for wound dressing applications.

We report here the synthesis of silver nanoparticles (AgNPs) from an aqueous extract of Juniperus excelsa and their use as an antimicrobial agent on their own or in combination with antibiotics in inhibiting multidrug-resistant bacteria (MDR). One strategy of bacterial infection control in wound healing is AgNP biosynthesis. We collected bacterial strains of patient skin infections from Al-Adwani Hospital. Phenotyping, biotyping, and molecular characterizations were applied using 16S rRNA gene analysis of bacterial isolates. Our results identified tested MDR bacteria Staphylococcus aureus strains (methicillin-resistantand methicillin-susceptible) and Proteus mirabilis. Gas chromatography/mass spectrometry (GC/MS) analysis was used to identify the Juniperus excelsa biomolecules in the leaf extract acting as both reducing and capping agents in the biosynthesis of AgNPs. The AgNPs appeared hexagonal and spherical in shape upon transmission electron microscope (TEM) analysis. The AgNP sizes ranged from 16.08 to 24.42nm. X-ray diffraction (XRD) analysis confirmed the crystalline nature of the particles. The minimum inhibitory concentrations (MICs) of the AgNPs against the tested MDR bacteria ranged from 48 to 56µg/ml, while the minimum bactericidal concentrations (MBCs) of the AgNPs against the tested strains ranged from 72 to 96µg/ml. The AgNPs showed a good synergistic efficacy with Cefaclor, Cefoxitin, and Erythromycin. Their efficiency showed a threefold increase in the inhibition of tested strains when used in wound dressing, due to the AgNPs potentially activating the antibiotics. Consequently, we can use AgNPs with Cefaclor, Cefoxitin, and Erythromycin antibiotics as alternative antimicrobial agents, and they could be utilized in wound dressing to prevent microbial infections.

Trends in bacterial bloodstream infections and resistance in immuno-compromised patients with febrile neutropenia: a retrospective analysis.

Bacterial infections remain a major cause of morbidity and mortality in immunocompromised children. From the onset of fever, an early administration of broad-spectrum antibiotics is begun; this strategy could induce emergence of multi-drug resistant bacteria (MDR). We describe the incidence and microbiological spectrum, including MDR bacteria of bacterial documented blood-stream infections (BSI) in immunocompromised children. A retrospective, descriptive study was conducted in a tertiary referral centre in France from January 2014 to December 2017. Our cohort included a large scale of patients with febrile neutropenia: haematological and oncological malignancies, haematopoietic stem cell transplantations, severe combined immunodeficiency syndromes. BSI were defined by positive blood culture samples associated with fever. Among 760 febrile neutropenia episodes in 7301 admitted patients, we identified 310 documented BSI with a mean of 7.4 BSI/1000 patient bed days. Only 2.9% BSIs were caused by MDR bacteria, none vancomycin resistant. Coagulase-negative staphylococci were identified in 49.7% BSI and Staphylococcus aureus caused 6.5% infections. Gram-negative bacilli accounted for 21.6% of isolated bacteria, Pseudomonas for 4.8%. The incidence of BSI annually decreased by 0.75% (p = 0.002).Conclusion: With a step-down strategy at 48h of initial broad-spectrum antibiotic therapy, we reported a low number of MDR bacteria, no deaths related to BSI. What is Known: • Bacterial bloodstream infections are a leading cause of morbidity and mortality in immunocompromised children • Multi-drug resistant bacteria are emerging worldwide. What is New: • Initial broad-spectrum antibiotic therapy with a step-down strategy at 48h: no deaths related to bloodstream infections with a low number of resistant bacteria. • Parental and nurse stewardship to decrease bloodstream infections incidence with a drop of staphylococcal infections.

Acquisition of multidrug-resistant bacteria and colistin resistance genes in French medical students on internships abroad

BackgroundAcquisition of multidrug resistant bacteria (MDR) and colistin resistance genes by international travellers has been demonstrated. Studies conducted in medical students during internships abroad are scant. MethodsNasopharyngeal, rectal, and vaginal swabs samples were collected from 382 French medical students before and after travel to investigate the acquisition of MDR bacteria. The bacterial diversity in the samples was assessed by culture on selective media. We also genetically characterised the isolates of MDR bacteria including Extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-E), methicillin-resistant Staphylococcus aureus (MRSA), and Carbapenemase-producing Enterobacteriacae (CPE) using the real-time polymerase chain reaction method. The samples were collected from 293 students and were investigated for mcr colistin-resistance genes using RT-PCR directly on the samples, followed by conventional PCR and sequencing. ResultsA proportion of 29.3% (112/382) of the participants had acquired ESBL-E and 2.6% (10/382) had acquired CPE. The most common species and ESBL-E encoding gene were Escherichia coli (125/127 isolates, 98.4%) and blaCTX-M-A (121/127, 95.3%), respectively. A proportion of 6.8% (20/293) of the participants had acquired mcr-1 genes, followed by mcr-3 (1/293, 0.3%) and mcr-8 (1/293, 0.3%). We found that taking part in humanitarian missions to orphanages (aRR = 2.01, p < 0.0001), being in contact with children during travel (aRR = 1.78, p = 0.006), the primary destination of travel being Vietnam (aRR = 2.15, p < 0.0001) and north India (aRR = 2.41, p = 0.001), using antibiotics during travel (aRR = 1.77, p = 0.01), and studying in 2018 (aRR = 1.55, p = 0.03) were associated with the acquisition of ESBL-E. When the primary destination of travel was Vietnam (aRR = 2.74, p < 0.0001) and the year of study was 2018 (aRR = 1.93, p < 0.002), this was associated with acquisition of colistin resistance genes. ConclusionMedical students are at a potential risk of acquiring ESBL-E, CPE and colistin resistance genes. A number of risk factors have been identified, which may be used to develop targeted preventive measures.

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.

Multidrug-Resistant Bacteria Isolated from Different Aquatic Environments in the North of Spain and South of France.

Due to the global progress of antimicrobial resistance, the World Health Organization (WHO) published the list of the antibiotic-resistant “priority pathogens” in order to promote research and development of new antibiotics to the families of bacteria that cause severe and often deadly infections. In the framework of the One Health approach, the surveillance of these pathogens in different environments should be implemented in order to analyze their spread and the potential risk of transmission of antibiotic resistances by food and water. Therefore, the objective of this work was to determine the presence of high and critical priority pathogens included in the aforementioned list in different aquatic environments in the POCTEFA area (North Spain–South France). In addition to these pathogens, detection of colistin-resistant Enterobacteriaceae was included due its relevance as being the antibiotic of choice to treat infections caused by multidrug resistant bacteria (MDR). From the total of 80 analyzed samples, 100% of the wastewater treatment plants (WWTPs) and collectors (from hospitals and slaughterhouses) and 96.4% of the rivers, carried antibiotic resistant bacteria (ARB) against the tested antibiotics. Fifty-five (17.7%) of the isolates were identified as target microorganisms (high and critical priority pathogens of WHO list) and 58.2% (n = 32) of them came from WWTPs and collectors. Phenotypic and genotypic characterization showed that 96.4% were MDR and resistance to penicillins/cephalosporins was the most widespread. The presence of bla genes, KPC-type carbapenemases, mcr-1 and vanB genes has been confirmed. In summary, the presence of clinically relevant MDR bacteria in the studied aquatic environments demonstrates the need to improve surveillance and treatments of wastewaters from slaughterhouses, hospitals and WWTPs, in order to minimize the dispersion of resistance through the effluents of these areas.

GC-MS-FID characterization and antibacterial activity of the Mikania cordifolia essential oil and limonene against MDR strains

The present study evaluated the effect of the essential oil of Mikania cordifolia (EOMc) and its major constituent limonene alone or associated with antibacterial drugs against Multidrug Resistant Bacteria (MDR). To evaluate the antibacterial activity, the minimum inhibitory concentrations (MIC) of the oil and limonene against Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus were determined. The antibiotic-modulating activity was assessed using subinhibitory concentrations (MIC/8) of these substances in combination with conventional antibacterial drugs. Although no relevant antibacterial activity of the natural products was detected, both substances modulated the action of antibiotics against resistant bacteria. The EOMc demonstrated the best modulating effect against P. aeruginosa, presenting synergistic effects when associated with gentamicin and norfloxacin. In addition, the oil reduced the MIC of norfloxacin against E. coli as well as reduced the MIC of gentamicin against S. aureus. On the other hand, the best effect of limonene was obtained against S. aureus. Thus, it is concluded that the essential oil Mikania cordifolia and the isolated compound limonene do not have clinically significant antibacterial effect, but modulate the action of antibiotics against MDR bacteria.