Multidrug-resistant Microorganisms Research Articles

Emergence of colistin-resistant Enterobacter cloacae and Raoultella ornithinolytica carrying the phosphoethanolamine transferase gene, mcr-9, derived from vegetables in Japan.

Colistin, a last-line antimicrobial agent, is recommended for the treatment of severe infections caused by multidrug-resistant (MDR) microorganisms. However, reports on plasmid-mediated mobilized colistin resistance (mcr) genes have prompted the importance of routine colistin resistance surveillance. Herein, we report the emergence of Enterobacter cloacae CST17-2 and Raoultella ornithinolytica CST129-1 carrying an mcr-9.1 gene in vegetables from Japan. A total of 308 colistin-resistant isolates were retrieved from 200 fresh vegetables in Hiroshima Prefecture, Japan. PCR detection of mcr-1 to mcr-9 was conducted. While none of the isolates detected positive for mcr-1 to mcr-8 genes, we found two (0.65%) positive strains, E. cloacae CST17-2 and R. ornithinolytica CST129-1, that harbored mcr-9.1 allele. These isolates were subjected to phenotypic susceptibility testing, whole-genome sequencing (WGS), PCR-based replicon typing, and conjugation experiment. We found that both isolates had high colistin resistance [minimum inhibitory concentration (MIC) 16 or >64 µg/mL] and showed MDR phenotypes. WGS of both isolates revealed mcr-9 on a plasmid of the IncHI2/HI2A backbone. The mcr-9-bearing plasmid, pCST17-2_1, was self-transferable, although the pCST129-1_1 plasmid was not. Despite being colistin-resistant, the so-called two-component regulatory operon, qseBC, which induces polymyxin resistance, was absent from the genetic arrangements downstream of mcr-9 in R. ornithinolytica CST129-1. Nonetheless, a conjugation experiment demonstrated that mcr-9 in a Raoultella-type background is capable of mediating colistin resistance. In silico genomic analysis and comparison revealed distinct genetic structures surrounding mcr-9, especially in the downstream vicinities. The E. cloacae CST17-2 strain is of sequence-type ST738, a sequence type that has emerged in mcr-9.1-containing E. cloacae. Remarkably, we report the first mcr-9-carrying colistin-resistant Enterobacteriaceae isolated from Japanese vegetables, which is a grave public health concern. Our findings highlight the importance of strict epidemiological monitoring to track and/or prevent further dissemination of mcr homologs across the vegetable industry.IMPORTANCEPlasmid-mediated mobile colistin-resistance genes have been recognized as a global threat because they jeopardize the efficacy of colistin in therapeutic practice. Here, we described the genetic features of two mcr-9.1-carrying Gram-negative bacteria with a colistin-resistant phenotype derived from vegetables in Japan. The colistin-resistant mcr-9.1, which has never been detected in vegetables, was located on a large plasmid in Enterobacter cloacae CST17-2 and Raoultella ornithinolytica CST129-1, suggesting a high chance of horizontal gene transfer. To the best of our knowledge, this is the first report of mcr-9 in R. ornithinolytica. This study indicates that fresh vegetables might be a potential source for the transmission of mcr-9 genes encoding resistance to frontline (colistin) and clinically relevant antimicrobials. The study also provides additional consideration for colistin use and the relevance of routine surveillance in epidemiological perspective to curb the continuous spread of mcr alleles.

Pharmacotechnical aspects of a stable probiotic formulation toward multidrug-resistance antibacterial activity: design and quality control

As a well-known group of the probiotic family, the Lactobacillus has increasingly contributed to hindering the growth of pathogens, particularly resistant species, in the last decades. Since antibiotic resistance has become a severe problem in global healthcare systems and considerably increased the mortality and morbidity rate in infectious diseases, we aimed to obtain a new stable formulation of Lactobacillus to overcome resistant infections. For this purpose, we designed various gel formulations containing Lactobacillus rhamnosus (L. rhamnosus) as an active pharmaceutical ingredient (API) in a water base and oil base gel, evaluated the probiotic stability in formulation to obtain an optimum formulation, and finally, investigated the antibacterial activities of that against two common hospital-associated multidrug-resistant pathogens, methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus (VRE). Furthermore, the pharmaceutical aspects of the optimum formulation, including stability, homogeneity, spreadability, pH value, conductivity, and rheological behavior, were assessed.The results indicated that the optimum formulation based on glycerol exhibited desirable pharmaceutical properties, including long-term stability, a perfect level of homogeneity, an acceptable range of spreadability with pseudo-plastic thixotropic behavior, and a promising antibacterial potential against MRSA and VRE. Our findings indicate that this novel probiotic formulation could be an excellent candidate to cope with antibiotic-resistant species, representing a hopeful treatment potential for topical applications, particularly in incurable infections. However, further in vivo studies seem warranted to evaluate their bactericidal activity against multi-drug resistant microorganisms.

Exploring the use of cluster analysis to assess antibiotic stewardship in critically-ill neonates in a low resource setting

BackgroundSepsis is the third leading cause of neonatal death in low and middle-income countries, accounting for one third of all deaths in Ethiopia. A concerning issue is the increasing number of multidrug-resistant microorganisms facilitated by suboptimal antibiotic stewardship. The study aims to identify clusters of newborns switching antibiotic lines for sepsis in a neonatal intensive care unit (NICU) in Ethiopia, and to explore their potential association with sepsis outcomes.MethodsA retrospective cohort study was conducted including all newborns discharged with a diagnosis of probable neonatal sepsis from the St. Luke Catholic Hospital NICU between April and July 2021. The antibiotic management protocol included two lines according to WHO guidelines and a third line based on internal hospital guidelines. In the cluster analysis, the Gower distance was estimated based on the antibiotics employed in the different lines and the duration of each line. Mortality and respiratory distress (RD) were the response variables.ResultsIn the study period, 456 newborns were admitted to the NICU and 196 (42.8%) had probable neonatal sepsis. Four antibiotic management clusters were identified. Cluster 1 (n = 145, 74.4%) had no antibiotic switches, using only the first line. Cluster 2 (n = 26, 13.3%) had one switch from the first to the second line. Cluster 4 (n = 9, 4.6%) had two switches: from first to second and then to third line. In cluster 3 (n = 15, 7.7%), newborns were switched from ceftriaxone/cloxacillin as second line to off-protocol antibiotics. There were no differences in sex, age, weight on admission or crude mortality between clusters. Cluster 3 included a higher frequency of infants who did not breathe at birth (53.3%, p = 0.011) and that necessitated bag ventilation (46.7%, p = 0.039) compared to the other clusters.ConclusionsThe first antibiotic line failed in one out of four newborns with probable sepsis while third-generation cephalosporins were insufficient in one in ten patients. Cluster analysis can provide valuable insights into antibiotic treatment patterns and their potential implications. This approach may support antibiotic stewardship and aid in contrasting antimicrobial resistance in limited resource settings.

Multiple drug resistant enterobacteria from biofilms in some tap water supplies in a Nigerian university

Tap outlets have been found to contain biofilms, which are a consortium of bacteria, fungi, viruses and protozoa. These microorganisms, especially Gram negative bacteria, could be pathogenic and highly resistant to antibiotics, leading to an increase in the prevalence of diseases worldwide. The university community depends on water from boreholes for consumption and domestic uses; as such, the need to identify the Gram negative bacteria is expedient. The main objective of this research is to determine the potability of the water released from the taps, and ultimately reduce the incidence of biofilm-related water infections. Water samples were collected from five boreholes and five tap outlets were swabbed with a sterile swab stick. Coliforms were estimated from the water samples using the Most Probable Number (MPN) technique. Gram negative bacteria were isolated and identified from the swabbing using standard bacteriological and biochemical tests. The antibiotic resistance patterns of the isolates were also determined, and the genes responsible for the multiple antibiotic resistance were identified using the DNA extraction and Polymerase Chain Reaction (PCR) methods. Bacterial counts of the samples ranged from 6.0×105cfu/mL to 1.4×106cfu/mL. MPN values of the tap water samples ranged from 4 to 1100+cfu/100mL, which exceeded the WHO standards of water quality. A total of 31 bacteria were isolated, of which 8 (25.8%) were Pseudomonas sp, 7 (22.6%) were Proteus sp, 4 (12.9%) were Klebsiella sp, 4 (12.9%) were Escherichia coli, 3 (9.7%) were Enterobacter sp, 3 (9.7%) were Citrobacter sp and 2 (6.5%) were Salmonella sp. All the bacteria showed multiple drug resistance to different antibiotics used, especially the cephalosporins. The gene found to be responsible for the cephalosporin resistance was the TEM - 445. Tap swabbing and water samples were found to contain a high value of coliforms (4 – 1100cfu/100mL), showing heavy faecal pollution, many of which could be pathogenic microorganisms that renders the water unfit for human consumption. The presence of these multidrug resistant microorganisms in the tap outlets could pose a serious threat to public health.

In vitro activity of cefiderocol and other newly approved antimicrobials against multi-drug resistant Gram-negative pathogens recovered in intensive care units in Spain and Portugal.

The antimicrobial resistance is a significant public health threat, particularly for healthcare-associated infections caused by carbapenem-resistant Gram-negative pathogens which are increasingly reported worldwide. The aim of this study was to provide data on the in vitro antimicrobial activity of cefiderocol and that of commercially available comparator antibiotics against a defined collection of recent clinical multi-drug resistant (MDR) microorganisms, including carbapenem resistant Gram-negative bacteria collected from different regions in Spain and Portugal. A total of 477 clinical isolates of Enterobacterales, Pseudomonas aeruginosa, Acinetobacter baumannii and Stenotrophomonas maltophilia were prospectively (n=265) and retrospectively (n=212) included (2016-2019). Susceptibility testing was performed using standard broad microdilution and results were interpreted using CLSI-2021 and EUCAST-2021 criteria. Overall, cefiderocol showed a good activity against Enterobacterales isolates, being 99.5% susceptible by CLSI and 94.5% by EUCAST criteria. It also demonstrated excellent activity against P. aeruginosa and S. maltophilia isolates, all being susceptible to this compound considering CLSI breakpoints. Regarding A. baumannii (n=64), only one isolate was resistant to cefiderocol. Our results are in agreement with other studies performed outside Spain and Portugal highlighting its excellent activity against MDR gram-negative bacteria. Cefiderocol is a therapeutic alternative to those available for the treatment of infections caused by these MDR bacteria.

Pre-transplant multidrug-resistant infections in liver transplant recipients-epidemiology and impact on transplantation outcome.

Cirrhotic patients are highly exposed to healthcare services and antibiotics. Although pre-liver transplantation (LT) infections are directly related to the worsening of liver function, the impact of these infections on LT outcomes is still unclear. This study aimed to identify the effect of multidrug-resistant microorganism (MDRO) infections before LT on survival after LT. Retrospective study that included patients who underwent LT between 2010 and 2019. Variables analyzed were related to patients' comorbidities, underlying diseases, time on the waiting list, antibiotic use, LT surgery, and occurrences post-LT. Multivariate analyses were performed using logistic regression, and Cox regression for survival analysis. A total of 865 patients were included; 351 infections were identified in 259 (30%) patients, of whom 75 (29%) had ≥1 pre-LT MDRO infection. The most common infection was spontaneous bacterial peritonitis (34%). The agent was identified in 249(71%), 53(15%) were polymicrobial. The most common microorganism was Klebsiella pneumoniae (18%); the most common MDRO was ESBL-producing Enterobacterales (16%), and carbapenem-resistant (CR) Enterobacterales (10%). Factors associated with MDRO infections before LT were previous use of therapeutic cephalosporin (p=.001) and fluoroquinolone (p=.001), SBP prophylaxis (p=.03), ACLF before LT (p=.03), and days of hospital stay pre-LT (p<.001); HCC diagnosis was protective (p=.01). Factors associated with 90-day mortality after LT were higher MELD on inclusion to the waiting list (p=.02), pre-LT MDRO infection (p=.04), dialysis after LT (p<.001), prolonged duration of LT surgery (p<.001), post-LT CR-Gram-negative bacteria infection (p<.001), and early retransplantation (p=.004). MDRO infections before LT have an important impact on survival after LT.

Trends of HAI and AMR in Italian intensive care units: findings from the SPIN-UTI network

Abstract Introduction Healthcare-associated infections (HAIs) and antimicrobial resistance (AMR) pose a significant burden on Public Health. Although it is undeniable that the COVID-19 pandemic provoked challenges in routine clinical practices and surveillance, especially in intensive care units (ICUs), its impact on HAIs and AMR is still highly debated. The present analysis describes trends of HAIs and multidrug-resistant (MDR) microorganisms in Italian ICUs from 2006 to 2021. Methods According to the European Center for Disease Prevention and Control (ECDC) protocol, we used data on nearly 22,000 patients and 4,500 isolates from the “Italian Nosocomial Infections Surveillance in Intensive Care Units, SPIN-UTI” project. The study population consists of all patients admitted to Italian ICUs for more than 48 hours. Isolates of Pseudomonas aeruginosa, Acinetobacter baumannii, Escherichia coli and Klebsiella pneumoniae were classified as MDR if susceptible to at least one antimicrobial agent in three or more antibiotic classes. Results Overall, the incidence density of HAIs increased from 17.1 per 1,000 patient-days in 2006-2007 to 24.1 in 2020-2021. Part of this increase can be attributed to the increasing incidence density of pneumoniae (p &amp;lt; 0.001). Although the proportion of MDR microorganisms did not significantly change over the years, increasing trends were evident in the incidence density of MDR isolates for A. baumannii (from 1.3 to 3.2 per 1,000 patient-days) and K. pneumoniae (from 0.5 to 3.1 per 1,000 patient-days). By contrast, the proportion of methicillin-resistant Staphylococcus aureus decreased from 46.9% in 2006 to 30.2% in 2021 (p-&amp;lt;0.05). Conclusions Our analysis shows an increasing trend in the incidence of HAIs and MDR microorganisms in Italian ICUs. This scenario has been surely worsened by the COVID-19 pandemic. It is still unclear, however, if the increasing incidence of AMR can be attributed to an overall increase in HAIs or to other causes. Key messages • In Italian ICUs, the incidence of HAIs and MDR microorganisms increased from 2006 to 2021. • Further studies should be conducted to estimate the impact of COVID-19 pandemic on HAIs and AMR.

Prevalence and Shifts in Antibiotic Use in an Italian Hospital: A Comparison of 2016 and 2022 Data

Abstract Background Antibiotics are among the most commonly prescribed drugs, but inappropriate prescription rates (molecule, duration or dosage) remain high, leading to the selection of multidrug-resistant microorganisms. This study aims to describe the most commonly used antibiotics in our hospital and compare them to 2016 data. Methods Conducted in November 2022 at the Azienda Ospedaliera Universitaria delle Marche of Ancona (Italy), the study followed the protocol proposed by the European Center for Disease Prevention and Control (ECDC). Patients admitted to wards before 8 a.m. and not discharged at the time of the survey were included. Data from 2022 were compared to the 2016 study. Results In 2022, 41.7% (N = 284) of the 681 patients were taking at least one antibiotic, with 400 antibiotic therapies administered, of which 90.5% were given parenterally. Among the patients on antimicrobial therapy, 40% were being treated for a community infection, 27% for a hospital acquired infection and 19% for surgical prophylaxis. Among all the antimicrobial prescriptions used, the most used class of antibiotics in 2022 was penicillin / beta lactamase inhibitor (21.6%, N = 86), followed by third-generation cephalosporins (11.8%, N = 47), carbapenems (11.6%, N = 46), glycopeptides (8.8%, N = 35), first-generation cephalosporins (8.8%, N = 35) and fluoroquinolones (7.0%, N = 28). Data from 2016 registered a 21.2% prevalence of penicillin / beta lactamase inhibitor, 15.7% of fluoroquinolones, 14.7% of third-generation cephalosporins, 10.5% first-generation cephalosporins, 7.6% of carbapenems and 4.1% of glycopeptides. Conclusions The prevalence of antibiotics used in our hospital has changed after six years. This shift may be due to new patterns of bacterial resistance and new antimicrobial drugs (e.g. cefiderocol). Key messages • Our study found a shift in prevalence of antibiotic use in our hospital after six years. • Penicillin/beta lactamase inhibitors are still the most commonly used antibiotics in our hospital.

Comparative Investigation into the Roles of Imipenem:Cyclodextrin Complexation and Antibiotic Combination in Combatting Antimicrobial Resistance in Gram-Negative Bacteria.

Extensively drug-resistant (XDR), multidrug-resistant (MDR) and pandrug-resistant (PDR) Gram-negative microorganisms (GNBs) are considered a significant global threat. β-lactam and aminoglycoside combinations and imipenem:cyclodextrin inclusion complexes were studied for the treatment of lethal GNBs. This is because of the broad empiric coverage of the two drugs and their possession of different spectra of activity. Two cyclodextrins (β- and hydroxy propyl β-cyclodextrins) were utilized for inclusion complex formation with imipenem using the physical and kneading methods. In silico investigation using the molecular docking and Fourier-infrared spectroscopy (FTIR) were employed to estimate binding constant and confirm complex formation, respectively. The in vitro effects of amikacin and imipenem combination in comparison to the effect of imipenem-β- and hydroxy propyl β-cyclodextrin (CD) complexes against Klebsiella spp. and Acinetobacter baumannii were studied. The isolated microorganisms' antimicrobial responsiveness to various antibiotics (19 antibiotics) was evaluated. It was found that piperacillin/tazobactam and gentamycin (resistance rates were 33.3% and 34%, respectively) were the most effective antimicrobials. The in vitro studies have been performed by the checkerboard technique and time-killing assay. The studied combination of amikacin and imipenem showed a substantial drop in bacterial count (p < 0.05). The in vitro studies demonstrated a synergism for the investigated combination. Conventional PCR was used in molecular studies to identify the resistance genes bla IMP and aac (6')-Ib. The blaIMP and aac (6')-Ib were recorded in 38.2% and 3.6% of the studied isolates, respectively. The in vitro studies showed synergistic effects among the tested antibiotics with FICIs of ≤0.5. Finally, the study compared the reduction in bacterial count between the tested antibiotic combinations and imipenem:CD physical and kneaded mixtures. Imipenem:CD inclusion complexes demonstrated a significant bacterial count reduction over the antibiotic combination. These results highlight the emerging role of CDs as safe biofunctional excipients in the combat against superbug bacterial resistance.

Inoculum size-insensitive susceptibility determination of urine sample based on in-situ measurement of inducible enzyme activity after 20 min of antibiotic exposure

BackgroundThe empirical antibiotic therapies for bacterial infections cause the emergence and propagation of multi-drug resistant bacteria, which not only impair the effectiveness of existing antibiotics but also raise healthcare costs. To reduce the empirical treatments, rapid antimicrobial susceptibility testing (AST) of causative microorganisms in clinical samples should be conducted for prescribing evidence-based antibiotics. However, most of culture-based ASTs suffer from inoculum effect and lack differentiation of target pathogen and commensals, hampering their adoption for evidence-based antibiotic prescription. Therefore, rapid ASTs which can specifically determine pathogens’ susceptibilities, regardless of the bacterial load in clinical samples, are in urgent need. ResultsWe present a pathogen-specific and inoculum size-insensitive AST to achieve the reliable susceptibility determination on Escherichia coli (E. coli) in urine samples. The developed AST is featured with an 1 h sample-to-result workflow in a filter, termed on-filter AST. The AST results can be obtained by using an inducible enzymatic assay to in-situ measure the cell response of E. coli collected from urine after 20 min of antibiotic exposure. The calculated detection limit of our AST (1.95 × 104 CFU/mL) is much lower than the diagnosis threshold of urinary tract infections. The specific expression of the inducible enzyme enables on-filter AST to correctly profile the susceptibilities of target pathogen to multi-type antibiotics without the interference from commensals. We performed the on-filter AST on 1 mL urine samples with bacterial loads varying from 105 CFU/mL to 107 CFU/mL and compared the results to that of standard method, demonstrating its insensitivity to inoculum size. SignificanceThe developed AST is demonstrated to be of high sensitivity, specificity, and insensitive to inoculum size. With further developments for additional bacteria and clinical validation, on-filter AST is promising as a rapid and reliable surrogate of culture-based AST to promote the evidence-based prescription at the first visit and minimize the emergency of new multi-drug resistant microorganisms.

Prevalence of Colonization with Multidrug-Resistant Bacteria: Results of a 5-Year Active Surveillance in Patients Attending a Teaching Hospital.

Combating antimicrobial resistance (AMR) requires comprehensive efforts, such as screening to identify patients colonized by multidrug-resistant microorganisms (MDROs). The primary purpose of this study was to estimate the AMR pattern of methicillin-resistant Staphylococcus aureus (MRSA) isolated from nasal surveillance swabs and MDROs isolated from pharyngeal and rectal surveillance swabs in patients attending a teaching hospital. Data were sought retrospectively, from 1 January 2017 to 31 December 2021, from the records produced by the hospital microbiology laboratory. Duplicate isolates, defined as additional isolates of the same microorganism with identical antibiograms, were excluded. Among Staphylococcus aureus isolates from nasal swabs, 18.2% were oxacillin-resistant. Among Gram-negative bacteria, 39.8% of Klebsiella pneumoniae and 83.5% of Acinetobacter baumannii isolates were carbapenem-resistant. Resistance to three antibiotic categories was high among Acinetobacter baumannii (85.8%) and Klebsiella pneumoniae (42.4%). The present data highlight a high prevalence of MDRO colonization among patients admitted to the hospital and suggest that screening for MDROs could be an important tool for infection control purposes, especially in geographical areas where limiting the spread of MDROs is crucial. The results also underline the importance of active surveillance, especially for carbapenem-resistant, Gram-negative bacteria in reducing their transmission, especially in high-risk units.

Isolation, Identification and Antibiotic Resistance of Different Clinical Isolates in Savar Area, Bangladesh

Introduction: The rise of multidrug-resistant (MDR) microorganisms, which pose a grave threat, has made choosing antibiotics to treat bacterial infections incredibly challenging. The prescription antibiotics have to consistently be effective against the identified related infections. Thus the research team wanted to find the antibiotic sensitivity profiles and pathogenic bacterial isolates in various patient specimens. Methods: The collection of 403 clinical samples of throat swabs, sputum, blood, stool, and urine from people of both genders and various ages was performed aseptically. Identification was carried out by microscopic, cultural, biochemical, and serological analysis. Finally, the disk diffusion method by Kirby-Bauer was employed to determine antibiotic responsiveness profiling. Results: A total of 93 samples (23.08%) were identified as positive isolates comprising 28.74% (25/87) of urine culture, followed by 24.32% (27/111) of blood, 23.08% (15/65) of stool, 20% (07/35) of throat swabs, and 18.1% (19/105) of sputum culture. Gram-negative bacteria 81(87.1%) showed more prevalence than Gram-positive bacteria 12 (12.90%). The most frequently identified isolates were Klebsiella spp. (24%), Salmonella spp. (23%), E. coli (17%), Pseudomonas spp. (5%), and Enterococcus spp. (3%). The infections showed more prevalence within the age group of 16-46 years (60.2%) and among males (48%) than females (46%). Conclusions: It was found that E. coli was the most abundant bacteria isolated from urine, Klebsiella spp. was the most abundant bacteria isolated from sputum and throat swabs, and Shiga toxin-producing Escherichia coli was the most abundant bacteria isolated from stool. Amikacin, Ciprofloxacin, Gentamicin, Imipenem, and Levofloxacin were considerably effective antibiotics, whereas Cefotaxime, Ceftazidime, Cefuroxime, Mecillinam, and Meropenem were least effective.

Food-Borne Diseases and their Impact on Health

Food safety remains a vulnerable issue in the face of foodborne disease outbreaks, which have significant consequences for individuals, the food industry, and the economy. This article aimed to investigate the impact of food borne diseases on food quality along with the public health concerns related to contaminated foods. This study was conducted through secondary data extracted from the literature on an emerging and concerning topic, which revealed that the emergence of antibiotic resistance in foodborne bacteria has a significant impact on public health. Resistant bacterial infections pose considerable costs to society and threats to food safety and the health of the population as a whole. Multidrug-resistant microorganisms causing illnesses possess several biological mechanisms to counteract the drugs’ effectiveness and avoid being killed by them. It has been extracted that foodborne illnesses are caused by bacterial infections from various pathogens, including Clostridium perfringens, Clostridium botulinum, Listeria monocytogenes, Vibrio spp., Shigella spp., Escherichia coli, Campylobacter spp., and Salmonella spp. Foodborne illness epidemiological surveillance methods are powerful tools for monitoring the phenomenon that occurs in populations. These population-based approaches, focused on advancing technology and advanced molecular subtyping available to public health laboratories, are essentially suitable for cooperation with foodborne diseases correlated with cluster-produced and widely distributed food products.

Programa de detección y control de la infección y colonización de enterobacterias productoras de carbapenemasas en una Unidad de Cuidados Intensivos Pediátricos en Colombia

IntroductionCarbapenemase-producing Enterobacteriaceae (CPEs) are one of the multidrug-resistant microorganisms of greatest public health concern because they are a major cause of nosocomial infections, leading to higher costs, hospital stays, and increased mortality. This problem is increasingly frequent in the pediatric population with mortality rates due to associated infections of up to 50%. With this paper we would like to present and describe our experience in the implementation of a CLD detection and control program in our PICU. MethodsA system of detection and screening through a search policy that defines the groups at risk and detects patients at risk of colonization by CLD, makes timely isolation of patients colonized with positive CLD and patients considered at risk of colonization pending the results of the culture, finally the control and monitoring of patients colonized by CLD. ResultsDuring the period from 2017 - 2020, 1548 patients were admitted to the PICU of the Hospital Universitario Fundación Santa Fe de Bogotá and it was determined that 6.1% of these met at least one risk factor for colonization by CLD; consequently, 95 screenings were performed in 4 years. At the end of the period studied, a cumulative incidence of CLD colonization of 18.94% was obtained among patients with risk factors. ConclusionsWe cannot analyze the factors associated with survival or find a significantly lower or higher survival rate by age; but at the end of follow-up we can affirm that this active surveillance strategy favors the rapid stratification of patient risk and the timely initiation of adequate antimicrobial therapy in early stages of infection. Also, timely and targeted treatment has been shown to improve clinical outcomes in high-risk patient populations, including patients with hematologic pathologies, and allows the development of personalized sepsis care plans.

Synergistic action of endophytic fungi secondary metabolites against multidrug-resistant strains of Staphylococcus aureus

The global threat to treatment of infections associated with multidrug-resistant microorganisms as well as side effects associated with combination therapy calls for the urgent development of new medicines to address these challenges. Endophytic fungi are efficient bio synthesizers and offer a wide array of these reliable bioactive compounds. The present study is aimed at evaluating the effect of combined extracts of endophytic fungi isolated from the leaves of Musa paradisiaca against multidrug-resistant Staphylococcus aureus (MRSA) strains. Screening for multidrug resistance was carried out using the Kirby-Bauer disc diffusion assay followed by a preliminary assay of endophytic fungal extracts bioactivity using agar diffusion assay against selected MRSA. A synergistic study using checkerboard assay technique was performed, then extracts were subjected to quantitative evaluation of secondary metabolites using Gas Chromatography with Flame Ionization Detector. Axenic cultures of five endophytic fungi from M. paradisiaca (EMp1-Emp5) were isolated from the sampled leaves. All the endophytic fungal extracts inhibited the growth of all the multi-drug resistant Staphylococcus aureus at 0.5 mg/mL. Varying inhibition zones that were concentration-dependent were observed. The combined effects of EMp3 and EMp5 extracts at 9:1; 8:2; 4:6; 3:7; and 2:8 combination ratios produced synergistic effects against S. aureus (S18) with very low Fractional inhibitory Concentrations of 0.03:0.01, 0.01:0.01, 0.006:0.02, 0.01:0.04 and 0.01:0.1 mg/mL respectively. Several bioactive secondary metabolites such as anthocyanin, (-) epicatechin, naringenin, resveratrol, catechin, rutin, phenol were produced by the fungal endophytes. Our findings further affirm fungal endophytes associated with M. paradisiaca leaves as producers of natural antibacterial agents with synergistic potentials.

Investigation of Phytochemicals and Antibacterial Activity of Persicaria odorata (L.) Methanolic Leaf Extract Against Selected Bacteria

Multidrug-resistant microorganisms pose serious threats, especially to children from developing countries. Due to this concern, there is a greater need to develop potentially effective antibacterial agents from natural resources. This study aimed to investigate the phytochemical compounds of Persicaria odorata (L.) methanolic leaf extract and its antibacterial activity against selected bacteria. Agar well diffusion and broth microdilution were used to test gram-positive (Staphylococcus aureus and Bacillus cereus) and gram-negative bacteria (Salmonella enterica serovar typhimurium and Shigella flexneri). The bacteria were treated with P. odorata (L.) leaves extracted using methanol and diluted with 10% Dimethyl-sulfoxide (DMSO). P. odorata (L.) leaf extract was highly effective against S. aureus at a concentration of 1,000 mg/mL. Gram-positive bacteria had the lowest MIC and MBC values. The qualitative phytochemical analysis of the methanolic extract of P. odorata (L.) leaves indicated the presence of antibacterial compounds such as phenols, flavonoids, terpenoids, and tannins. In conclusion, P. odorata (L.) leaves which have been widely used in cuisines and traditional medicine also possess the potential to serve as an antibacterial agent.

Evaluation of In Vitro Antimicrobial, Antioxidant, and Anti-Quorum Sensing Activity of Edible Mushroom (Agrocybe aegerita).

In the present study, ethanol extract obtained from the mycelial culture of Agrocybe aegerita was evaluated for its antioxidant activity as well for its potential to inhibit the virulence factor responsible for quorum-sensing activity and antibiofilm activity of pathogenic Pseudomonas aeruginosa PAO1 strain. The extract of mushroom at different concentrations showed percentage inhibition in a dose-dependent manner for DPPH and nitric oxide assays with the lowest as 38.56 ± 0.11% and 38.87 ± 0.04% at 50 µg/mL and the highest as 85.63 ± 0.12% and 82.34 ± 0.12% at 200 µg/mL. FTIR analysis confirmed the presence of functional group -OH, O-H bending bonds, C=C stretching, pyranose ring, and H-C-H stretch, confirming the presence of phenol, carotenoid, and ascorbic acid. HPLC analysis revealed that the concentration of gallic acid present in the extract is 27.94 mg/100 g which is significantly (p < 0.05) more than the concentration of rutin (i.e., 7.35 mg/100 g). GC-MS analysis revealed the presence of 5-methyl-1-heptanol, 2-heptadecenal, phthalic acid, butyl hept-4-yl ester, 2-dodecanol, benzoic acid, TMS derivative. The extract showed significantly (p < 0.05) more inhibition of pyocyanin (61.32%) and pyoverdine (54.02%). At higher concentrations of mushroom extract, there was a significant (p < 0.05) reduction (56.32%) in the swarming motility of the test organism. The extract showed 72.35% inhibition in biofilm formation. Therefore, it has been concluded from the present study that mushroom extract, which is rich in phenolic compounds interferes with the virulence factor responsible for quorum sensing, thereby inhibiting biofilm formation, and can be utilized as therapeutic agents against multi-drug resistant pathogenic microorganisms.

Molecular Docking Study of the C-10 Massoia Lactone Compound as an Antimicrobial and Antibiofilm Agent against Candida tropicalis.

Antimicrobial resistance is now considered a global health problem because it reduces the effectiveness of antimicrobial drugs. According to the World Health Organization (WHO), the highest mortality rate is associated with infections caused by multidrug-resistant microorganisms, with approximately 700,000 deaths worldwide each year. The aim of this study was to determine the potential of C-10 massoia lactone to inhibit the growth of fungi and C. tropicalis biofilm, and molecular docking studies were performed to determine the nature of the inhibition. The study was conducted using the microdilution method for antifungal and antibiofilm testing and designed with a molecular docking approach. Furthermore, an analysis using the scanning electron microscope (SEM) was performed to evaluate the mechanism of effect. The results obtained showed that C-10 massoia lactone can inhibit the growth of fungi by 84.21% w/v. Meanwhile, the growth of C. tropicalis biofilm in the intermediate phase was 80.23% w/v and in the mature phase was 74.23% w/v. SEM results showed that C-10 massoia lactone damaged the EPS matrix of C. tropicalis so that hyphal formation was hindered due to damage to fungal cells, resulting in a decrease in attachment, density, and lysis of C. tropicalis fungal cells. Based on molecular docking tests, C-10 massoia lactone was able to inhibit biofilm formation without affecting microbial growth, while docking C-10 massoia lactone showed a significant binding and has the potential as an antifungal agent. In conclusion, the C-10 massoia lactone compound has the potential as an antibiofilm against C. tropicalis, so it can become a new antibiofilm agent.

Microwave-assisted solvent-free synthesis of some novel thiazole substituted thiosemicarbazone analogues: Antimicrobial and anticancer studies.

The increased resistance to antibiotics has compelled researchers to devise novel active compounds targeting multidrug-resistant pathogenic microorganisms. A series of thiosemicarbazone derivatives were synthesized by reacting thiosemicarbazide with 2-aryl-4-formylthiazole, 2-aryl-5-formyl-4-methylthiazole, and/or 5-acetyl-2-aryl-4-methylthiazole compounds. These thiosemicarbazone-based thiazole adducts were evaluated for their inhibitory activities against tuberculosis H37Ra and Bovis BCG mycobacteria. Their cytotoxicity was assessed against two cancer cell lines: colonic carcinoma (HCT-116) and cervical cancer (HeLa). Notably, these thiosemicarbazones exhibited minimal cytotoxic effects on these cell lines even at their highest concentrations. Furthermore, the prepared thiosemicarbazone derivatives demonstrated significant antimicrobial efficacy against Bacillus subtilis and Staphylococcus aureus (gram-positive bacterial pathogens) as well as Escherichia coli and Pseudomonas fluorescens (gram-negative bacterial pathogens). While most of the prepared thiosemicarbazone derivatives exhibited moderate activity against Candida albicans (a fungal strain), their performance was notable. The thiosemicarbazone-based thiazole adducts were also successfully synthesized using a solvent-free approach under microwave irradiation. Compared with conventional reflux methods, the microwave-assisted technique yielded high thiazole yields within just 5 minutes, obviating the need for catalysis. This study signifies significant strides toward the rational design of more potent antimycobacterial agents.

The Contribution of Antimicrobial Peptides to Immune Cell Function: A Review of Recent Advances.

The development of novel antimicrobial agents to replace antibiotics has become urgent due to the emergence of multidrug-resistant microorganisms. Antimicrobial peptides (AMPs), widely distributed in all kingdoms of life, present strong antimicrobial activity against a variety of bacteria, fungi, parasites, and viruses. The potential of AMPs as new alternatives to antibiotics has gradually attracted considerable interest. In addition, AMPs exhibit strong anticancer potential as well as anti-inflammatory and immunomodulatory activity. Many studies have provided evidence that AMPs can recruit and activate immune cells, controlling inflammation. This review highlights the scientific literature focusing on evidence for the anti-inflammatory mechanisms of different AMPs in immune cells, including macrophages, monocytes, lymphocytes, mast cells, dendritic cells, neutrophils, and eosinophils. A variety of immunomodulatory characteristics, including the abilities to activate and differentiate immune cells, change the content and expression of inflammatory mediators, and regulate specific cellular functions and inflammation-related signaling pathways, are summarized and discussed in detail. This comprehensive review contributes to a better understanding of the role of AMPs in the regulation of the immune system and provides a reference for the use of AMPs as novel anti-inflammatory drugs for the treatment of various inflammatory diseases.