Droplets generated from toilets during urination as a possible vehicle of carbapenem-resistant Klebsiella pneumoniae

BACKGROUND

In the health care setting, infection control actions are fundamental for containing the dissemination of multidrug-resistant bacteria (MDR). Carbapenemase-producing Enterobacterales (CPE), especially Klebsiella pneumoniae (CR-KP), can spread among patients, although the dynamics of transmission are not fully known. Since CR-KP is present in wastewater and microorganisms are not completely removed from the toilet bowl by flushing, the risk of transmission in settings where toilets are shared should be addressed. We investigated whether urinating generates droplets that can be a vehicle for bacteria and explored the use of an innovative foam to control and eliminate this phenomenon.

METHODS

To study droplet formation during urination, we set up an experiment in which different geometrical configurations of toilets could be reproduced and customized. To demonstrate that droplets can mobilize bacteria from the toilet bowl, a standard ceramic toilet was contaminated with a KPC-producing Klebsiella pneumoniae ST101 isolate. Then, we reproduced urination and attached culture dishes to the bottom of the toilet lid for bacterial colony recovery with and without foam.

RESULTS

Rebound droplets invariably formed, irrespective of the geometrical configuration of the toilet. In microbiological experiments, we demonstrated that bacteria are always mobilized from the toilet bowl (mean value: 0.11 ± 0.05 CFU/cm2) and showed that a specific foam layer can completely suppress mobilization.

CONCLUSIONS

Our study demonstrated that droplets generated from toilets during urination can be a hidden source of CR-KP transmission in settings where toilets are shared among colonized and noncolonized patients.

Characteristics of and risk factors for biliary pathogen infection in patients with acute pancreatitis

Background

Infection in patients with acute pancreatitis, especially severe acute pancreatitis patients, is a common and important phenomenon, and the distributions and drug resistance profiles of bacteria causing biliary infection and related risk factors are dynamic. We conducted this study to explore the characteristics of and risk factors for bacterial infection in the biliary tract to understand antimicrobial susceptibility, promote the rational use of antibiotics, control multidrug-resistant bacterial infections and provide guidance for the treatment of acute pancreatitis caused by drug-resistant bacteria.

Methods

The distribution of 132 strains of biliary pathogenic bacteria in patients with acute pancreatitis from January 2016 to December 2020 were analyzed. We assessed drug resistance in the dominant Gram-negative bacteria and studied the drug resistance profiles of multidrug-resistant bacteria by classifying Enterobacteriaceae and nonfermentative bacteria. We then retrospectively analyzed the clinical data and risk factors associated with 72 strains of Gram-negative bacilli, which were divided into multidrug-resistant bacteria (50 cases) and non-multidrug-resistant bacteria (22 cases).

Results

The main bacteria were Escherichia coli, Acinetobacter baumannii, Klebsiella pneumoniae and Pseudomonas aeruginosa. Extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli had a 66.67% detection rate. Acinetobacter baumannii had more than 50.00% drug resistance to carbapenems, ESBL-producing Klebsiella pneumoniae had 100.00% drug resistance, and Pseudomonas aeruginosa had 66.67% resistance to carbapenems. Multivariate logistic regression analysis suggested that the administration of third- or fourth-generation cephalosporins was an independent risk factor for Gram-negative multidrug-resistant biliary bacterial infection in acute pancreatitis patients.

Conclusion

Drug resistance among biliary pathogens in acute pancreatitis patients remains high; therefore, rational antimicrobial drug use and control measures should be carried out considering associated risk factors to improve diagnosis and treatment quality in acute pancreatitis patients.

A cluster of Achromobacter xylosoxidans led to identification of Pseudomonas aeruginosa and Serratia marcescens contamination at a long-term-care facility

A cluster of Achromobacter xylosoxidans, an emerging multidrug-resistant aquaphilic bacterium, was identified in 3 long-term-care facility residents. As Pseudomonas aeruginosa and Serratia marcescens were also present in clinical specimens, we conducted an investigation of all 3 water-associated species and identified P. aerguniosa and S. marcescens contamination at the facility. Sequencing analysis linked P. aeruginosa to a clinical isolate. Findings highlight the need for precautionary measures to prevent transmission of water-associated multidrug-resistant bacteria in long-term-care facilities.

Dealing with MDR bacteria and biofilm in the post-antibiotic era: Application of antimicrobial peptides-based nano-formulation

The rapid development of multidrug-resistant (MDR) bacteria due to the improper and overuse of antibiotics and the ineffective performance of antibiotics against the difficult-to-treat biofilm-related infections (BRIs) have urgently called for alternative antimicrobial agents and strategies in combating bacterial infections. Antimicrobial peptides (AMPs), owing to their compelling antimicrobial activity against MDR bacteria and BRIs without causing bacteria resistance, have attracted extensive attention in the research field. With the development of nanomaterial-based drug delivery strategies, AMPs-based nano-formulations have significantly improved the therapeutic effects of AMPs by ameliorating their hydrolytic stability, half-life in vivo, and solubility as well as reducing the cytotoxicity and hemolysis, etc. This review has comprehensively summarized the application AMPs-based nano-formulation in various bacterial infections models, including bloodstream infections (specifically sepsis), pulmonary infections, chronic wound infections, gastrointestinal infections, among others. The design of the nanomaterial-based drug delivery systems and the therapeutic effects of the AMPs-based nano-formulations in literature have been categorized and in details discussed. Overall, this review provides insights into the advantages and disadvantages of the current developed AMPs-based nano-formulations in literature for the treatment of bacterial infections, bringing inspirations and suggestions for their future design in the way towards clinical translation.

Spontaneous bacterial peritonitis and extraperitoneal infections in patients with cirrhosis

Infections are a frequent complication and a major cause of death among patients with cirrhosis. The important impact of infections in general and especially spontaneous bacterial peritonitis on the course of disease and prognosis of patients with cirrhosis has been recognized for many years. Nevertheless, such importance has recently increased due to the comprehension of infection as one of the most prominent risk factors for patients to develop acute-on-chronic liver failure. Furthermore, the issue of infections in cirrhosis is a focus of increasing attention because of the spreading of multidrug resistant bacteria, which is an emerging concern among physicians assisting patients with cirrhosis. In the present paper, we will review the current epidemiology of infections in patients with cirrhosis and particularly that of infections caused by resistant bacteria, demonstrating the relevance of the subject. Besides, we will discuss the current recommendations on diagnosis and treatment of different kinds of infections, including spontaneous bacterial peritonitis, and we will highlight the importance of knowing local microbiological profiles and choosing empirical antibiotic therapy wisely. Finally, we will debate the existing evidences regarding the role of volume expansion with albumin in patients with cirrhosis and extraperitoneal infections, and that of antibiotic prophylaxis of spontaneous bacterial peritonitis.

[Pathogenic bacteria characteristics and antimicrobial treatment plan for liver cirrhosis combined with spontaneous bacterial peritonitis]

Spontaneous bacterial peritonitis (SBP) is a common complication in patients with liver cirrhosis, and it is also an important inducement for patients with liver cirrhosis to develop into an acute decompensated stage, and thereby has become the concern and difficulties of clinical treatment. SBP pathogenic bacteria varies with time and region, and the confirmed detection rate of Gram-positive bacteria and multidrug-resistant bacteria has been increasing year by year. Therefore, whether the antimicrobial treatment plan based on the previous guidelines is still applicable remains to be further explored. This paper focuses on introducing the pathogenic bacteria characteristics for cirrhosis combined with SBP in different study populations, different regions, different time, and different infection modes, and further summarizes empirical antimicrobial treatment plan according to the changes of SBP pathogenic bacteria, in order to provide theoretical basis for clinical treatment.

The antibacterial activity of fluoroquinolone derivatives: An update (2018-2021)

Bacterial infection is amongst the most common diseases in community and hospital settings. Fluoroquinolones, exerting the antibacterial activity through binding to type II bacterial topoisomerase enzymes, DNA gyrase and topoisomerase IV, are mainstays of chemotherapy. At present, fluoroquinolones are the most valuable antibacterial agents used popularly. However, the emergence of more virulent and resistant pathogens by the development of either mutated DNA-binding proteins or efflux pump mechanism for fluoroquinolones results in an urgent demand to develop new fluoroquinolones to withstand the drug resistance and to obtain a broader spectrum of activity. This review aims to outline the recent advances of fluoroquinolone derivatives with antibacterial potential and to summarize the structure-activity relationship (SAR) so as to provide an insight for rational design of more active candidates, covering articles published between January 2018 and June 2021.

Pharmacological importance of TG12 from tachykinin and its toxicological behavior against multidrug-resistant bacteria Klebsiella pneumonia

Development of antimicrobial drugs against multidrug-resistant (MDR) bacteria is a great focus in recent years. TG12, a short peptide molecule used in this study was screened from tachykinin (Tac) protein of an established teleost Channa striatus (Cs) transcriptome. Tachykinin cDNA has 345 coding sequence, that denotes a protein contained 115 amino acids; in which a short peptide (TG12) was identified at 83-94. Tachykinin mRNA upregulated in C. striatus treated with Aeromonas hydrophila and Escherichia coli lipopolysaccharide (LPS). The mRNA up-regulation was studied using real-time PCR. The up-regulation tachykinin mRNA pattern confirmed the immune involvement of tachykinin in C. striatus during infection. Further, the identified peptide, TG12 was synthesized and its toxicity was demonstrated in hemolytic and cytotoxic assays using human erythrocytes and human dermal fibroblast cells, respectively. The toxicity study exhibited that the toxicity of TG12 was similar to negative control, phosphate buffer saline (PBS). Moreover, the antibiogram of TG12 was active against Klebsiella pneumonia ATCC 27736, a major MDR bacterial pathogen. Further, the antimicrobial activity of TG12 against pathogenic bacteria was screened using minimum inhibitory concentration (MIC) and anti-biofilm assays, altogether TG12 showed potential activity against K. pneumonia. Fluorescence assisted cell sorter flow cytometer analysis (FACS) and field emission scanning electron microscopy (FESEM) was carried on TG12 with K. pneumonia; the results showed that TG12 significantly reduced K. pneumonia viability as well as TG12 disrupt its membrane. In conclusion, TG12 of CsTac is potentially involved in the antibacterial immune mechanisms, which has a prospectus efficiency in pharma industry against MDR strains, especially K. pneumonia.

Antibacterial properties of Allium sativum L. against the most emerging multidrug-resistant bacteria and its synergy with antibiotics

Garlic has long been known as the most effective plant species in treatment of bacterial infections. Considering the vast potential of garlic as a source of antimicrobial drugs, this study is aimed to evaluate the antibacterial activity of Allium sativum extracts and their interactions with selected antibiotics against drug-sensitive and multidrug-resistant isolates of emerging bacterial pathogens that are frequently found in healthcare settings. As shown by the in vitro data obtained in this study, the whole Allium sativum extract inhibited the growth of a broad range of bacteria, including multidrug-resistant strains with bactericidal or bacteriostatic effects. Depending on the organism, the susceptibility to fresh garlic extract was comparable to the conventional antibiotic gentamycin. Since the combinations of fresh garlic extract with gentamycin and ciprofloxacin inhibited both the drug sensitive and MDR bacteria, in most cases showing a synergistic or insignificant relationship, the potential use of such combinations may be beneficial, especially in inhibiting drug-resistant pathogens. The study results indicate the possibility of using garlic as e.g. a supplement used during antibiotic therapy, which may increase the effectiveness of gentamicin and ciprofloxacin.

Dose recommendations for intravenous colistin in pediatric patients from a prospective, multicenter, population pharmacokinetic study

OBJECTIVES

The aim of this study was to describe the population pharmacokinetics of intravenous colistin use in children and to propose optimal dosage regimens.

METHODS

A prospective, multicenter, population pharmacokinetic (PPK) study was conducted. Phoenix 64 version 8.3 was used for the PPK analysis. Simulations were performed to estimate the probability of target attainment for patients achieving target plasma colistin average steady-state concentrations (C_ss,avg).

RESULTS

A total of 334 plasma colistin concentrations were obtained from 79 pediatric patients with a median age (interquartile range) of 2.6 years (0.8-6.8 years); 73 (92.4%) were admitted to intensive care units. Colistin pharmacokinetics were adequately described by a one-compartment model with first-order elimination along with serum creatinine (SCr) as a significant covariate in colistin clearance. The simulation demonstrated that the recommended dose of 5 mg of colistin base activity (CBA)/kg/day resulted in 18.2-63.0% probability of achieving a target C_ss,avg of 2 mg/l. With a lower targeted C_ss,avg of 1 mg/l, colistin dosing with 7.5 mg and 5 mg of CBA/kg/day were adequate for children with SCr levels of 0.1-0.3 mg/dl and >0.3 mg/dl, respectively.

CONCLUSIONS

SCr is a significant covariate in colistin clearance in children. Colistin dosing should be selected according to the patient's SCr level and the desired target C_ss,avg.

Isolation and characterization of lytic phage TUN1 specific for Klebsiella pneumoniae K64 clinical isolates from Tunisia

BACKGROUND

Multidrug-resistant Klebsiella pneumoniae spp. (kp) are emerging agents of severe infections of the respiratory, urinary tract and wounds that can progress to fatal septicemia. The use of bacteriophages is currently being considered as an effective alternative or adjuvant to antibiotic therapy.

RESULTS

In this study, we report capsule (K)-typing of 163 carbapenem-resistant Kp (CRKP) isolated 2014-2018 at the Military Hospital of Instruction of Tunis (MHT), Tunisia, by partial amplification and sequencing of the Kp wzi gene. The most prevalent K-type overall was K64 with 50.3% followed by K17 and K27 (22.7 and 11.0%, respectively). K64 Kp strains were most common and associated with increased case/fatality rates, especially at the intensive care unit (ICU). Using a K64 Kp strain we isolated and characterized a lytic Kp phage, vB_KpP_TUN1 (phage TUN1), from wastewater samples of the ICU at the MHT. TUN1 belongs to the Autographiviridae family and specifically digests K64 Kp capsules most probably via a depolymerase encoded by gp47. Furthermore, we successfully assembled phage TUN1 in a non-replicative host (E. coli) raising the possibility of in vitro assembly in the absence of live bacterial hosts. We propose that phage TUN1 is a promising candidate to be used as an adjuvant or an alternative to antibiotic therapy in CRKP infections, facilitating regulatory approval of phage therapy.

CONCLUSIONS

K64, K17 and K27 are the most common wzi capsule types in this geographical location in Northern Africa. The lytic phage TUN1 efficiently lyses K64 Kp strains associated with increased case/fatality rates at body temperature. Together with its ability to be rescued in a non-replicative host these features enhance the utility of this phage as an antibacterial agent.

Prevalence of multidrug-resistant bacteria in Ethiopia: a systematic review and meta-analysis

OBJECTIVES

Multidrug-resistant (MDR) bacteria are a significant public-health threat worldwide, especially in low- and middle-income countries. Comprehensive data are important to understand the magnitude of multidrug resistance (MDR), however these are not available in Ethiopia.

METHODS

Five electronic databases and grey literature of Addis Ababa University Repository were searched for data regarding the prevalence of MDR bacteria in Ethiopia. OpenMetaAnalyst R1.3 was used for analysis using a random-effects model to determine the effect size. Heterogeneity among articles was checked using the inconsistency index (I²). Funnel plot was used to check for publication bias. The quality of each article was checked using the Newcastle-Ottawa checklist adapted for cross-sectional studies.

RESULTS

Through database searching, 2094 articles were identified, of which 37 fulfilled the study inclusion criteria. This review comprises 6856 bacteria, of which 4949 isolates were MDR. The overall pooled prevalence of MDR was 70.5% (95% CI 64.9-76.1%), with considerable heterogeneity (I² = 97.48%, P < 0.001). Funnel plot revealed no publication bias. Sidama (81.7%) had the highest MDR and Tigray (51.1%) the lowest. The greatest source of MDR was from multiple sites of infection (MSI) (76.8%); the least was from bloodstream infections (62.9%). MDR was higher in studies conducted on hospital-acquired infections (72.1%) compared with both hospital- and community-acquired infections (69.8%).

CONCLUSION

Our study indicates a high prevalence of MDR in Ethiopia. Sidama region, MSI and hospital-acquired infections showed the highest MDR in subgroup analysis. Regional hospitals should implement infection prevention and proper use of antibiotics in the community.

Long-term complications and implant survival rates after cranioplastic surgery: a single-center study of 392 patients

Cranioplasty (CP) is a standard procedure in neurosurgical practice for patients after (decompressive) craniectomy. However, CP surgery is not standardized, is carried out in different ways, and is associated with considerable complication rates. Here, we report our experiences with the use of different CP materials and analyze long-term complications and implant survival rates. We retrospectively studied patients who underwent CP surgery at our institution between 2004 and 2014. Binary logistic regression analysis was performed in order to identify risk factors for the development of complications. Kaplan-Meier analysis was used to estimate implant survival rates. A total of 392 patients (182 females, 210 males) with a mean age of 48 years were included. These patients underwent a total of 508 CP surgeries. The overall complication rate of primary CP was 33.2%, due to bone resorption/loosening (14.6%) and graft infection (7.9%) with a mean implant survival of 120 ± 5 months. Binary logistic regression analysis showed that young age (< 30 years) (p = 0.026, OR 3.150), the presence of multidrug-resistant bacteria (p = 0.045, OR 2.273), and cerebrospinal fluid (CSF) shunt (p = 0.001, OR 3.137) were risk factors for postoperative complications. The use of titanium miniplates for CP fixation was associated with reduced complication rates and bone flap osteolysis as well as longer implant survival rates. The present study highlights the risk profile of CP surgery. Young age (< 30 years) and shunt-dependent hydrocephalus are associated with postoperative complications especially due to bone flap autolysis. Furthermore, a rigid CP fixation seems to play a crucial role in reducing complication rates.

The efficiency of cleaning in intensive care units: A systematic review

OBJECTIVES

This review aims to analyze the studies on cleaning practices and the efficiency of the cleaning carried out in environments that have a great risk of resistant microorganism infection, such as intensive care units.

METHODS

In this study, a retrospective literature review was undertaken of the relevant publications between the years 2005 and 2020, using the keywords "Cross Infection, Infection Control, Multidrug-Resistant Bacteria, Intensive Care, Room Cleaning, Environmental Cleaning, Hospital-Associated Infection"; using the international databases Pubmed, CINAHL and EBSCO and domestic database ULAKBIM on search engines. Titles and abstracts of all relevant articles found on electronic searches were reviewed by the researchers independently. The Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols guideline and Patient, Intervention, Comparison, Outcomes, Study design model were used in analysing the studies.

RESULTS

The selected studies were reviewed in four main categories: Materials used in cleaning, the period between taking environmental samples, cleaning methods, and the efficiency of cleaning. Among the studies included herein, eight were randomized controlled trials, three were retrospective intervention studies, two were case-control studies and one was a retrospective cohort study.

CONCLUSIONS

Today, the assessment of cleaning in environments can be evaluated by different methods, but there are advantages and disadvantages of these methods. Therefore, in the relevant literature, it is suggested that cleaning must be evaluated by several methods, not only one. Also, training the staff that carries out the cleaning and rewarding correct behavior by giving feedback are important approaches to increase the efficiency of cleaning. It is suggested that cleaning must be carried out every day, regularly with effective methods and equipment; frequency of cleaning during epidemics must be increased, institutions must prepare cleaning manuals according to evidence-based guidelines that are recognized at an international level.

Tandem fecal microbiota transplantation cycles in an allogeneic hematopoietic stem cell transplant recipient targeting carbapenem-resistant Enterobacteriaceae colonization: a case report and literature review

BACKGROUND

Due to limited antibiotic options, carbapenem-resistant Enterobacteriaceae (CRE) infections are associated with high non-relapse mortality after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Also, intestinal CRE colonization is a risk factor for subsequent CRE infection. Several clinical studies have reported successful fecal microbiota transplantation (FMT) for the gut decontamination of a variety of multidrug-resistant bacteria (MDRB), even in immunosuppressed patients. Similarly, other studies have also indicated that multiple FMTs may increase or lead to successful therapeutic outcomes.

CASE PRESENTATION

We report CRE colonization in an allo-HSCT patient with recurrent CRE infections, and its successful eradication using tandem FMT cycles at 488 days after allo-HSCT. We also performed a comprehensive microbiota analysis. No acute or delayed adverse events (AEs) were observed. The patient remained clinically stable with CRE-negative stool culture at 26-month follow-up. Our analyses also showed some gut microbiota reconstruction. We also reviewed the current literature on decolonization strategies for CRE.

CONCLUSIONS

CRE colonization led to a high no-relapse mortality after allo-HSCT; however, well-established decolonization strategies are currently lacking. The successful decolonization of this patient suggests that multiple FMT cycles may be potential options for CRE decolonization.

Antimicrobial peptides with symmetric structures against multidrug-resistant bacteria while alleviating antimicrobial resistance

In response to the dramatically increasing antimicrobial resistance, a series of new symmetric peptides were designed and synthesized in this study by a "WWW" motif as the symmetric center, arginine as the positive charge amino acid and the terminus symmetrically tagged with hydrophobic amino acids. Amongst the new symmetric peptide FRRW (FRRWWWRRF-NH₂) presented the highest cell selectivity for bacteria over mammalian cell and exerted excellent antimicrobial potential against a broad of bacteria, especially difficult-to-kill multidrug-resistant strains clinical isolates. FRRW also displayed perfect stability in physiological salt ions and rapid killing speed as well as acted on multiple mechanisms including non-receptor mediated membrane and intra-molecular mechanisms. Importantly, FRRW emerged a low tendency of resistance in contrast to traditional antibiotics ciprofloxacin and gentamicin. What's more, FRRW could resist or alleviate or even reverse the ciprofloxacin- and gentamicin-resistance by changing the permeability of bacterial membrane and inhibiting the efflux pumps of bacteria. Furthermore, FRRW exhibited remarkable effectiveness and higher safety in vivo than polymyxin B. In summary, the new symmetric peptide FRRW was promised to be as a new antimicrobial candidate for overcoming the increasing bacterial resistance.

Antibacterial fatty acids: An update of possible mechanisms of action and implications in the development of the next-generation of antibacterial agents

The antibacterial activity of fatty acids (FA) is well known in the literature and represents a promising option for developing the next-generation of antibacterial agents to treat a broad spectrum of bacterial infections. FA are highly involved in living organisms' defense system against numerous pathogens, including multidrug-resistant bacteria. When combined with other antibacterial agents, the remarkable ability of FA to enhance their bactericidal properties is a critical feature that is not commonly observed in other naturally-occurring compounds. More reviews focusing on FA antibacterial activity, traditional and non-traditional mechanisms and biomedical applications are needed. This review is intended to update the reader on the antibacterial properties of recent FA and how their chemical structures influence their antibacterial activity. This review also aims to better understand both traditional and non-traditional mechanisms involved in these recently explored FA antibacterial activities.

Phage therapy as strategy to face post-antibiotic era: a guide to beginners and experts

Interest in the therapeutic use of bacteriophages (phages) has emerged in recent years, driven mainly by the antimicrobial resistance crisis. This review aimed to summarize some important studies addressing the use of phages as a therapeutic alternative for multiresistant bacterial infections. To this end, a literature search was conducted to address the efficacy and versatility of phage therapy, the advantages and disadvantages of its use, and potential limitations for the application of phage therapy that need to be overcome, especially in Western countries. Thus, this review highlights that phage therapy may be a promising route in the treatment of infections caused by multidrug-resistant pathogens and that a combined approach has the potential to prolong the life of the current available antimicrobials. In addition, standardized clinical trials using monoclonal or polyclonal phages, alone or in combination with antimicrobials, are crucial to determine the real potential of these treatments in clinical practice.

Prevalence of multidrug-resistant bacteria colonisation among asylum seekers in western Switzerland

The recent increase of migration to Europe represents a risk of increased the prevalence of multidrug-resistant (MDR) bacteria. We conducted a cross-sectional study among asylum seekers admitted at two hospitals in Switzerland. Of the 59 patients included, 9 (14%) were colonised by a MDR bacteria, including 5 (8.5%) methicilin-resistant Staphylococcus aureus (MRSA) and 4 (6.8%) extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae. No patient carried both ESBL-producing bacteria and MRSA. None of the patients carried a vancomycin-resistant Enterococcus (VRE) or a carbapenem-resistant Enterobacteriaceae (CRE). Colonisation with MDR bacteria was not associated with hospitalisation abroad or recent arrival in Switzerland. Whole genome sequencing analysis allowed us to exclude transmission between patients. The prevalence of MDR bacteria carriage is moderate among asylum seekers in western Switzerland. Further surveillance studies are necessary to determine if there is a risk of dissemination of pathogens into the local population.

Microbial evolution of vascular graft infections in a tertiary hospital based on positive graft cultures

BACKGROUND

Vascular graft infections are a serious complication in vascular surgery. Correct antibiotic therapy targeted to the most likely infecting species is essential to treat these patients, although the bacterial epidemiology and pathogenesis are still not completely understood. We analyzed the behavior of vascular graft infections and the microbiologic patterns of resistance.

METHODS

A 10-year (2008-2018), single-center, retrospective cohort study was performed of all patients admitted with vascular graft infection identified by positive direct graft cultures. An extensive microbiologic study was performed to analyze the bacterial strains, antibiotic resistance and sensitivity, and prevalence stratified by the year.

RESULTS

A total of 72 vascular graft infections with positive graft cultures occurring in 65 patients were found. Their mean age was 67 ± 9.6 years, and 85% were men. Infection-related mortality was 11%. Of the 65 patients, 14 had undergone aortobifemoral bypass, 13 axillofemoral bypass, 5 femorofemoral bypass, 27 femoropopliteal bypass, and 4 femoral endarterectomy with synthetic patch angioplasty. The median interval from the index procedure to infection was longer for intracavitary than for extracavitary grafts (P = .011). Of the 72 infections, 48 were monomicrobial and 24 were polymicrobial. Gram-negative bacteria were predominantly identified in intracavitary graft infections (54%). In contrast, gram-positive bacteria were most frequent in the extracavitary graft group (58%). Multidrug-resistant bacterial species occurred more frequently in early graft infections (P = .002). Throughout the study duration, an overall decrease in gram-positive infections and an increase in gram-negative infections was observed, especially in extensively drug-resistant strains. A similar progression was found in all nosocomial infections.

CONCLUSIONS

The present study has shown that vascular graft infection microbiology changed in accordance with graft location and interval to infection from revascularization surgery and had also evolved over the study period with patterns similar to those for all nosocomial infections. This highlights the importance of studying the specific microbiology of each healthcare center and its relationship to vascular graft infections to achieve the best treatment possible.

AIEgens for microbial detection and antimicrobial therapy

Pathogenic microbes can cause infections or diseases in hosts and they pose ongoing threats to human health. Antibiotics have been taken an active role in treating a wide variety of infections or diseases since they were first introduced in the 1940s. However, the emergence of antibiotic-resistant microbes makes these previously effective drugs invalid regrettably. So it is urgently needed to accelerate research and development for new antimicrobial systems and strategies. Recently, luminogens with aggregation-induced emission characteristics (AIEgens) have emerged as powerful fluorescent tools for microbial detection and antimicrobial therapy. In this review, we highlighted the latest advancements of AIEgen-based biofunctional materials and systems in this research field. AIE fluorescent probes have the advantages of excellent sensitivity and rapid response, which make them useful for ultrafast bacterial imaging, bacteria classification, and pathogen discrimination. Early microbial detection and identification could help us study the mechanism of antibiotic resistance more scientifically. Moreover, the AIEgens-based photosensitizers (AIE-PSs) with strong photosensitization show good performance on the efficient elimination of multidrug-resistant bacteria and intracellular bacteria. At the end of the review, a short perspective on aggregate science is concluded.

Antibacterial and antibiofilm potential of silver nanoparticles against antibiotic-sensitive and multidrug-resistant Pseudomonas aeruginosa strains

Due to the severity of infections caused by P. aeruginosa and the limitations in treatment, it is necessary to find new therapeutic alternatives. Thus, the use of silver nanoparticles (AgNPs) is a viable alternative because of their potential actions in the combat of microorganisms, showing efficacy against Gram-positive and Gram-negative bacteria, including multidrug-resistant microorganisms (MDR). In this sense, the aim of this work was to conduct a literature review related to the antibacterial and antibiofilm activity of AgNPs against antibiotic-sensitive and multidrug-resistant Pseudomonas aeruginosa strains. The AgNPs are promising for future applications, which may match the clinical need for effective antibiotic therapy. The size of AgNPs is a crucial element to determine the therapeutic activity of nanoparticles, since smaller particles present a larger surface area of contact with the microorganism, affecting their vital functioning. AgNPs adhere to the cytoplasmic membrane and cell wall of microorganisms, causing disruption, penetrating the cell, interacting with cellular structures and biomolecules, and inducing the generation of reactive oxygen species and free radicals. Studies describe the antimicrobial activity of AgNPs at minimum inhibitory concentration (MIC) between 1 and 200 μg/mL against susceptible and MDR P. aeruginosa strains. These studies have also shown antibiofilm activity through disruption of biofilm structure, and oxidative stress, inhibiting biofilm growth at concentrations between 1 and 600 μg/mL of AgNPs. This study evidences the advance of AgNPs as an antibacterial and antibiofilm agent against Pseudomonas aeruginosa strains, demonstrating to be an extremely promising approach to the development of new antimicrobial systems.

Stewardship actions for device associated infections: An intervention study in the emergency intensive care unit

Improving the practices of antimicrobial use in hospitals, especially in developing countries, is a challenging duty.

OBJECTIVES

The aim of the study was to determine the effect of certain stewardship actions on the use of antibiotics for device-associated infections in the emergency intensive care unit in Egypt.

MEHODS

The intervention included establishment of AS team, design an antibiogram and preparation of antibiotic use guidelines, education, and infection prevention and control measures. Pre- and postinterventions surveys tookplace including: antibiotic prescription compliance, antibiotic cost, bacterial profile and antibiotic resistance rates.

RESULTS

Antibiotic prescription compliance improved, especially for prophylactic antibiotics prescription; in preintervention phase, 27.4% of cases received unindicated antibiotic prophylaxis vs 5.8% after intervention. A statistically significant decrease in cost after the intervention was reported (p = 0.04). Acinetobacter baumannii and Klebsiella pneumonia were the most frequently isolated pathogens (25.6%) and (21.8%) in pre and post-intervention phases respectively. A statistically significant decrease in the prevalence of MDR (X² = 11.9, p = 0.009) was observed. The most prevalent XDR is K-pneumonia (45% vs 17%) in phase 1&3. No pan drug-resistant isolates were detected.

CONCLUSION

Sound antibiotic guidelines coupled with effective infection control precautions and education would be a good intervention, particularly with a leadership commitment. The use of microbiology tests to direct prescribing decisions should be a underscored. Sustained research initiatives may support the proper implementation of AS programmes in limited resource settings.

FabI (enoyl acyl carrier protein reductase) - A potential broad spectrum therapeutic target and its inhibitors

Development of new anti-bacterial agents acting upon underexploited targets and thus evading known mechanisms of resistance is the need of the hour. The highly conserved and distinct bacterial fatty acid biosynthesis pathway (FAS-II), presents a validated and yet relatively underexploited target for drug discovery. FabI and its isoforms (FabL, FabK, FabV and InhA) are essential enoyl-ACP reductases present in several microorganisms. In addition, the components of the FAS-II pathway are distinct from the multi-enzyme FAS-I complex found in mammals. Thus, inhibition of FabI and its isoforms is anticipated to result in broad-spectrum antibacterial activity. Several research groups from industry and academic laboratories have devoted significant efforts to develop effective FabI-targeting antibiotics, which are currently in various stages of clinical development for the treatment of multi-drug resistant bacterial infections. This review summarizes all the natural as well as synthetic inhibitors of gram-positive and gram-negative enoyl ACP reductases (FabI). The knowledge of the reported inhibitors can aid in the development of broad-spectrum antibacterials specifically targeting FabI enzymes from S. aureus, S. epidermidis, B. anthracis, B. cereus, E. coli, P. aeruginosa, P. falciparum and M. tuberculosis.

Fecal Microbiota Transplant in a Patient Infected with Multidrug-Resistant Bacteria: A Case Report

Introduction

There has been a growing interest in fecal microbiota transplantation (FMT) as a way to manipulate gut microbiota, with potential benefit in patients infected with multidrug-resistant (MDR) bacteria.

Case Presentation

We present the case of an 87-year-old male with recurrent ascending cholangitis due to biliary atony and impaired biliary drainage after multiple biliary sphincterotomies and two papillary balloon dilations. In this context, a choledochoduodenostomy was performed, but the patient kept on having repeated episodes of acute cholangitis, resulting in multiple hospitalizations, every other week, with need of multiple broad-spectrum antibiotic courses, which led to bacteremias with MDR microorganisms. Several therapeutic strategies such as prophylactic antibiotics (including rifaximin), pre- and probiotics, prokinetics, and ursodeoxycholic acid were unsuccessfully attempted. After multidisciplinary case discussion, an FMT was proposed, with the aim of manipulating gut microbiota and decreasing MDR bacteremias. We first performed FMT via colonoscopy in September 2018, after which the patient still had 3 more hospitalizations for acute cholangitis, but isolated bacteria in blood cultures were resistant only to amoxicillin and clavulanic acid. Considering this apparent change in the microbial resistance profile, we performed a second FMT in January 2019 via the upper gastrointestinal route. During the next 4 months, the patient remained well. In April 2019, the patient relapsed again with three more episodes of cholangitis, for which we repeated the FMT via upper gastrointestinal endoscopy. No readmissions were observed during the next 4 months. All three FMTs were performed without complications.

Discussion and Conclusion

FMT seems to be a safe procedure and was effective in decreasing hospital admissions and changing the profile of MDR bacteria previously isolated from blood cultures.