The use and abuse of antibiotics and the development of antibiotic resistance

Insect Cuticle Protein Nanoassemblies without Nonspecific Immune Response for Acute Methicillin-Resistant Staphylococcus aureus Pneumonia Remission

The emergence and proliferation of methicillin-resistant Staphylococcus aureus (MRSA) pneumonia poses a significant global public health threat. Herein, the significant remission effect against acute MRSA pneumonia was realized through the insect cuticle protein (OfCPH-2) nanoassemblies without nonspecific immune response. The lung repair results could be attributed to the transforming of M1-type to M2-type macrophage polarization and the repression of Th17 cell differentiation in mice spleens through the intervention of OfCPH-2 nanoassemblies. These findings offer a valuable insight into the application of insect protein-based materials as effective antidrug resistant strain agents as well as a powerful strategy for acute MRSA pneumonia.

Exploiting β-Lactams-Induced Lysis and DNA Fragmentation for Rapid Molecular Antimicrobial Susceptibility Testing of Neisseria Gonorrhoeae via Dual-Digital PCR

The evolution of antimicrobial resistance (AMR) presents substantial challenges to global medical health systems. Neisseria gonorrhoeae (N. gonorrhoeae), in particular, has developed resistance to all currently available antimicrobials. Addressing this issue necessitates not only discovering new antimicrobials but also deepening the understanding of bacterial responses to these agents, which can lead to new markers for rapid antimicrobial susceptibility testing (AST). Such advancements can enhance treatment outcomes and promote antimicrobial stewardship. In this study, single-cell techniques, including live-cell imaging, flow cytometry, and digital polymerase chain reaction (PCR) are utilized, to investigate the lysis dynamics and molecular features of N. gonorrhoeae upon exposure to β-lactam antimicrobials. Distinct patterns of bacterial lysis and DNA fragmentation are uncovered in susceptible strains. Leveraging these discoveries, A microfluidic dual-digital PCR approach that combines single-cell and single-molecule analyses, facilitating rapid and efficient phenotypic molecular AST for N. gonorrhoeae against β-lactams is developed. This proof-of-concept validation demonstrates the effectiveness of the method in accessing antimicrobial susceptibility across a range of bacterial strains, contributing valuable insights for advancing the battle against AMR.

Risk factors and mortality rates of carbapenem-resistant Gram-negative bacterial infections in intensive care units

Background

The prevalence of hospital-acquired infections caused by carbapenem-resistant gram-negative bacteria (CRGNB) is increasing worldwide. Several risk factors have been associated with such infections. The present study aimed to identify risk factors and determine the mortality rates associated with CRGNB infections in intensive care units.

Methods

This retrospective case-control study was conducted at Erciyes University Hospital (Kayseri, Turkey) between January 2017 and December 2021. Demographic and laboratory data were obtained from the Infection Control Committee data and record system. Patients who had CRGNB infection 48-72 h after hospitalization were assigned to the case group, while those who were not infected with CRGNB during hospitalization formed the control group. Risk factors, comorbidity, demographic data, and mortality rates were compared between the two groups.

Results

Approximately 1449 patients (8.97%) were monitored during the active follow-up period; of those, 1171 patients were included in this analysis. CRGNB infection developed in 14 patients (70.00%) who had CRGNB colonization at admission; in 162 (78.26%) were colonized during hospitalization, whereas 515 (54.56%) were not colonized. There was no significant difference in age, sex (male/female) or comorbidities. The total length of hospital stay was statistically significantly longer (P=0.001) in the case group (median: 24 [interquartile range: 3-378] days) than the control group (median: 16 [interquartile range: 3-135] days). The rates of colonization at admission (25.5%; vs. 10.6%, P=0.001) and mortality (64.4% vs. 45.8%, P=0.001) were also significantly higher in the cases than in the control group, respectively. In the univariate analysis, prolonged hospitalization, the time from intensive care unit admission to the development of infection, presence of CRGNB colonization at admission, transfer from other hospitals, previous antibiotic use, enteral nutrition, transfusion, hemodialysis, mechanical ventilation, tracheostomy, reintubation, central venous catheter, arterial catheterization, chest tube, total parenteral nutrition, nasogastric tube use, and bronchoscopy procedures were significantly associated with CRGNB infections (P <0.05). Multivariate analysis identified the total length of stay in the hospital (odds ratio [OR]=1.02; 95% confidence interval [CI]: 1.01 to 1.03; P=0.001), colonization (OR=2.19; 95% CI: 1.53 to 3.13; P=0.001), previous antibiotic use (OR=2.36; 95% CI: 1.53 to 3.62; P=0.001), intubation (OR=1.59; 95% CI: 1.14 to 2.20; P=0.006), tracheostomy (OR=1.42; 95% CI: 1.01 to 1.99; P=0.047), and central venous catheter use (OR=1.62; 95% CI: 1.20 to 2.19; P=0.002) as the most important risk factors for CRGNB infection.

Conclusions

Colonization, previous use of antibiotics, and invasive interventions were recognized as the most important risk factors for infections. Future research should focus on measures for the control of these parameters.

Antibiotic Susceptibility Profiling of Gram-Positive and Gram-Negative Bacterial Isolates in a Tertiary Care Hospital: Establishment of an Antibiogram

Introduction Antimicrobial resistance poses a significant global healthcare challenge in the management of bacterial infections, which is frequently attributed to rapid bacterial adaptations. This study aims to develop an antibiogram for a tertiary care hospital, providing comprehensive antibiotic sensitivity profiles for Gram-positive and Gram-negative bacteria. It informs healthcare providers of antibiotic resistance trends, enabling informed treatment decisions and enhanced infection control measures. Methods We conducted a six-month prospective observational study, during which we gathered and analyzed data from the microbiology laboratory to identify patterns of antimicrobial sensitivity. Subsequently, the data underwent analysis and interpretation using the respected WHONET software, a readily available tool designed for this specific task. Our methodology adhered to the guidelines established by the Clinical & Laboratory Standards Institute for the standardization of antibiogram generation procedures, and these guidelines are easily integrated into the WHONET software for analytical purposes. Results There were a total of 357 isolates across various hospital departments, comprising 13 distinct bacterial species. Among them, nine were identified as Gram-negative bacteria, accounting for 262 (73.3%) isolates. Escherichia coli accounted for 131 (36.6%) isolates, while Klebsiella accounted for 62 (17.3%), emerging as the predominant species among them. The remaining four bacterial species were identified as Gram-positive bacteria, totaling 95 (26.6%) isolates, with Staphylococcus aureus being the most frequently isolated species at 51 (14.2%), followed by Enterococcus at 26 (7.2%). Subsequent analysis using the WHONET software facilitated the creation of an antibiogram. Among the Gram-negative bacteria, E. coli displayed high sensitivity (100%) to aztreonam and clindamycin, followed by nitrofurantoin (98%), imipenem (94%), and meropenem (95%). However, it exhibited decreased sensitivity to ampicillin (25%), cefuroxime (34%), and ceftriaxone (39%). Conversely, among the Gram-positive bacteria, S. aureus demonstrated 100% sensitivity to ampicillin, amoxiclav, cefazolin, teicoplanin, linezolid, rifampicin, nitrofurantoin, and cefotaxime. However, it exhibited zero sensitivity to vancomycin and only 6% sensitivity to cotrimoxazole. Conclusion This study advances the understanding of antibiotic susceptibility in a tertiary care setting and provides an invaluable tool for optimizing treatment strategies, enhancing infection control measures, and combating antibiotic resistance.

BENEFITS OF A CLINICAL PATHWAY IN TOTAL KNEE ARTHROPLASTY

Objective

Demonstrate whether a multiprofessional Clinical Pathway Program in Total Knee Arthroplasty (CPPA) contributesto optimizing hospital care.

Method

Retrospective study of medical data of care indicators in 310 patients divided into two groups: A- who underwent arthroplasty in the last biennium before the introduction of the CPPA (n=144) and group B- who underwent TKA in the biennium after the introduction of the CPPA (n=166).

Results

Postoperative showed a significant difference in favor of group B over group A for hospitalization time in days 4.33 ± 2.79 and 5.4 ± 1.67 (p<0.001), time of prophylactic antibiotic in hours 28.13 ± 33.77 and 81.49 ± 40.91 (p<0.001), referral to the intensive care unit 40.9% and 73.4% (p<0.001), initiation of thromboprophylaxis within 24 hours 97.9% and 82.5% (p<0.001), use of elastic stockings and/or intermittent compression prescribed for thromboprophylaxis 89.5% and 31.2% (p<0.001), initiation of rehabilitation within 24 hours 90.1% and 66.1% (p<0.001), readmissions within 30 days 4.1% and 3% (p = 0.76), readmissions 90 days 2.7% and 6.6% (p = 0.183), transfusions 5.5% and 15.2% (p = 0.033).

Conclusion

The implementation of a multiprofessional CPPA contributed to the implementation of care protocols, favoring greater patient safety. Level of Evidence III; Retrospective Comparative Study.

Development of sensitizer peptide-fused endolysin Lys1S-L9P acting against multidrug-resistant gram-negative bacteria

The advent of multidrug-resistant (MDR) bacteria poses a major threat to public health, garnering attention to novel antibiotic replacements. Endolysin, a bacteriophage-derived cell wall-degrading enzyme, is a promising alternative to conventional antibiotics. However, it is challenging to control Gram-negative bacteria due to the presence of the outer membrane that shields the peptidoglycan layer from enzymatic degradation. To overcome this threshold, we constructed the fusion endolysin Lys1S-L9P by combining endolysin LysSPN1S with KL-L9P, a sensitizer peptide known to extend efficacy of antibiotics by perturbing the outer membrane of Gram-negative bacteria. In addition, we established a new endolysin purification procedure that increases solubility allowing a 4-fold increase in production yield of Lys1S-L9P. The sensitizer peptide-fused endolysin Lys1S-L9P exhibited high bactericidal effects against many MDR Gram-negative pathogens and was more effective in eradicating biofilms compared to LysSPN1S. Moreover, Lys1S-L9P showed potential for clinical use, maintaining stability at various storage temperatures without cytotoxicity against human cells. In the in vivo Galleria mellonella model, Lys1S-L9P demonstrated potent antibacterial activity against MDR Gram-negative bacteria without inducing any toxic activity. This study suggest that Lys1S-L9P could be a potential biocontrol agent to combat MDR Gram-negative bacteria.

Enhanced Transdermal Peptide-Modified Flexible Liposomes for Efficient Percutaneous Delivery of Chrysomycin A to Treat Subcutaneous Melanoma and Intradermal MRSA Infection

Superficial skin diseases, including skin infections and tumors, are common healthcare burdens. In this study, the in vivo activity of chrysomycin A (CA) is explored, and a transdermal liposomal CA formulation is further constructed for the simultaneous treatment of cutaneous melanoma and cutaneous methicillin-resistant Staphylococcus aureus (MRSA) infection. The prepared liposomes (TD-LP-CA) display a strong antitumor effect with an IC50 value of less than 0.1 µm in B16-F10 cells, suppress the proliferation of MRSA with a minimum inhibitory concentration (MIC) of 1 µm, and eradicate established MRSA biofilms at 10× MIC in vitro. More importantly, TD-LP-CA shows enhanced stratum corneum (SC) penetration, reaching more than 500 µm beneath the skin's surface due to modification with the TD peptide, and demonstrates excellent subcutaneous tumor penetration after skin application in vivo. TD-LP-CA displays an excellent therapeutic effect against intradermal MRSA infection in mice after topical dermal administration, as well as a moderate inhibitory effect on subcutaneous melanoma with a 75% tumor inhibition rate. The liposomes prepared herein can be a promising carrier for transcutaneous CA transfer for the treatment of superficial diseases such as skin tumors and infections due to their ability to overcome the skin barrier.

Eugenol works synergistically with colistin against colistin-resistant Pseudomonas aeruginosa and Klebsiella pneumoniae isolates by enhancing membrane permeability

Colistin is a potent antibiotic for the treatment of carbapenem-resistant Gram-negative bacteria and is considered a last-resort drug. Unfortunately, the incidence of colistin-resistant bacteria isolated from patients is continuously growing due to clinical reuse of colistin. In this study, we found that the combination of colistin and eugenol has a significant synergistic antibacterial effect and reverses the sensitivity of colistin-resistant Pseudomonas aeruginosa and Klebsiella pneumoniae against colistin, as confirmed by checkerboard and time-kill assays. Crystal violet staining and scanning electron microscopy revealed colistin and eugenol's synergistic antibiofilm action. Concerning the synergy mechanism, the results revealed that the combination of eugenol and colistin increases membrane permeability and causes considerable membrane damage, further inhibiting bacteria synergistically. Meanwhile, up to 500 µg/mL of eugenol is non-toxic to RAW 264.7 cells, and the colistin/eugenol combination is also efficacious in vivo, as demonstrated by the Galleria mellonella infection model. Our findings indicate that the colistin/eugenol combination is a viable treatment option for colistin-resistant P. aeruginosa and K. pneumoniae clinical infections. IMPORTANCE Colistin is used as a last resort for severe infections caused by multidrug-resistant Gram-negative bacteria, however, colistin resistance is increasing. As a result, we investigated the synergistic effect of eugenol/colistin combination, and the results revealed significant antibacterial and antibiofilm action. Eugenol may help clinical colistin-resistant Pseudomonas aeruginosa and Klebsiella pneumoniae recover their susceptibility. These findings suggest that combining eugenol and colistin may be a viable treatment option for colistin-resistant pathogen clinical infections.

Activity fingerprinting of AMR β-lactamase towards a fast and accurate diagnosis

Antibiotic resistance has become a serious threat to global public health and economic development. Rapid and accurate identification of a patient status for antimicrobial resistance (AMR) are urgently needed in clinical diagnosis. Here we describe the development of an assay method for activity fingerprinting of AMR β-lactamases using panels of 7 β-lactam antibiotics in 35 min. New Deli Metallo β-lactamase-1 (NDM-1) and penicillinase were demonstrated as two different classes of β-lactamases. The panel consisted of three classes of antibiotics, including: penicillins (penicillin G, piperacillin), cephalosporins (cefepime, ceftriaxone, cefazolin) and carbapenems (meropenem and imipenem). The assay employed a scheme combines the catalytic reaction of AMR β-lactamases on antibiotic substrates with a flow-injected thermometric biosensor that allows the direct detection of the heat generated from the enzymatic catalysis, and eliminates the need for custom substrates and multiple detection schemes. In order to differentiate classes of β-lactamases, characterization of the enzyme activity under different catalytic condition, such as, buffer composition, ion strength and pH were investigated. This assay could provide a tool for fast diagnosis of patient AMR status which makes possible for the future accurate treatment with selected antibiotics.

Joining Forces against Antibiotic Resistance: The One Health Solution

Antibiotic resistance is a significant global health concern that affects both human and animal populations. The One Health approach acknowledges the interconnectedness of human health, animal health, and the environment. It emphasizes the importance of collaboration and coordination across these sectors to tackle complex health challenges such as antibiotic resistance. In the context of One Health, antibiotic resistance refers to the ability of bacteria to withstand the efficacy of antibiotics, rendering them less effective or completely ineffective in treating infections. The emergence and spread of antibiotic-resistant bacteria pose a threat to human and animal health, as well as to the effectiveness of medical treatments and veterinary interventions. In particular, One Health recognizes that antibiotic use in human medicine, animal agriculture, and the environment are interconnected factors contributing to the development and spread of antibiotic resistance. For example, the misuse and overuse of antibiotics in human healthcare, including inappropriate prescribing and patient non-compliance, can contribute to the selection and spread of resistant bacteria. Similarly, the use of antibiotics in livestock production for growth promotion and disease prevention can contribute to the development of antibiotic resistance in animals and subsequent transmission to humans through the food chain. Addressing antibiotic resistance requires a collaborative One Health approach that involves multiple participants, including healthcare professionals, veterinarians, researchers, and policymakers.

Isolation of a bacteriophage targeting Pseudomonas aeruginosa and exhibits a promising in vivo efficacy

Pseudomonas aeruginosa is an important pathogen that causes serious infections. Bacterial biofilms are highly resistant and render bacterial treatment very difficult, therefore necessitates alternative antibacterial strategies. Phage therapy has been recently regarded as a potential therapeutic option for treatment of bacterial infections. In the current study, a novel podovirus vB_PaeP_PS28 has been isolated from sewage with higher lytic activity against P. aeruginosa. Isolated phage exhibits a short latent period, large burst size and higher stability over a wide range of temperatures and pH. The genome of vB_PaeP_PS28 consists of 72,283 bp circular double-stranded DNA, with G + C content of 54.75%. The phage genome contains 94 open reading frames (ORFs); 32 for known functional proteins and 62 for hypothetical proteins and no tRNA genes. The phage vB_PaeP_PS28 effectively inhibited the growth of P. aeruginosa planktonic cells and displayed a higher biofilm degrading capability. Moreover, therapeutic efficacy of isolated phage was evaluated in vivo using mice infection model. Interestingly, survival of mice infected with P. aeruginosa was significantly enhanced upon treatment with vB_PaeP_PS28. Furthermore, the bacterial load in liver and kidney isolated from mice infected with P. aeruginosa and treated with phage markedly decreased as compared with phage-untreated P. aeruginosa-infected mice. These findings support the efficacy of isolated phage vB_PaeP_PS28 in reducing P. aeruginosa colonization and pathogenesis in host. Importantly, the isolated phage vB_PaeP_PS28 could be applied alone or as combination therapy with other lytic phages as phage cocktail therapy or with antibiotics to limit infections caused by P. aeruginosa.

Short-term antibiotic therapy for the most common bacterial respiratory infections in infants and children

Overuse and misuse of antibiotics have strongly accelerated the progressive increase in bacterial antimicrobial resistance (AMR). The evidence that antimicrobial selective pressure was greater the longer the antibiotic therapy was continued has led some experts to reconsider duration of antibiotic therapy testing the use of short-term drug administration. If as effective as long-term therapy, short-term therapy could have been an easy measure to limit AMR emergence. In the present narrative review, whether present knowledge on short-term therapy of acute streptococcal pharyngitis (ASF), acute otitis media (AOM) and mild to moderate community-acquired pneumonia (CAP) allows systematic use of short-term therapy in infants and children with these diseases is discussed. Literature analysis showed that reducing the duration of antibiotic therapy for some of the most common pediatric respiratory infections could be a valid measure to contain the antibiotic abuse and the consequent impact on the emergence of AMR. Several data seem to indicate that this type of intervention is possible, as short-term therapy has been found as effective as the traditionally recommended long-term therapy in some cases of ASF, AOM and mild to moderate CAP. However, further studies are needed to better characterize infants and children who can have benefit with short-term antibiotic therapy in common bacterial respiratory infections.

Prevalence and distribution of antimicrobial resistance in effluent wastewater from animal slaughter facilities: A systematic review

The extensive use of antibiotics in food animal production and disposal of untreated wastewater from food animal slaughter facilities may create a shift in microbiomes of different ecosystems by generating reservoirs of antimicrobial resistance along the human-animal-environmental interface. This epidemiological problem has been studied, but its magnitude and impact on a global scale is poorly characterised. A systematic review was done to determine global prevalence and distribution patterns of antimicrobial resistance in effluent wastewater from animal slaughter facilities. Extracted data were stratified into rational groups for secondary analyses and presented as percentages. Culture and sensitivity testing was the predominant method; Escherichia spp., Enterococcus spp., and Staphylococcus aureus were the most targeted isolates. Variable incidences of resistance were detected against all major antimicrobial classes including reserved drugs such as ceftazidime, piperacillin, gentamicin, ciprofloxacin, and chloramphenicol; the median frequency and range in resistant Gram-negative isolates were: 11 (0-100), 62 (0-100), 8 (0-100), 14 (0-93) and 12 (0-62) respectively. Ciprofloxacin was the most tested drug with the highest incidences of resistance in livestock slaughterhouses in Iran (93%), Nigeria (50%) and China (20%), and poultry slaughterhouses in Germany (21-81%) and Spain (56%). Spatial global distribution patterns for antimicrobial resistance were associated with previously reported magnitude of antibiotic use in livestock or poultry farming and, the implicit existence of jurisdictional policies to regulate antibiotic use. These data indicate that anthropogenic activities in farming systems are a major contributor to the cause and dissemination of antimicrobial resistance into the environment via slaughterhouse effluents.

Shape Matters: Highly Selective Antimicrobial Bottle Brush Copolymers via a One-Pot RAFT Polymerization Approach

The one-pot synthesis of antimicrobial bottle brush copolymers is presented. Reversible addition-fragmentation chain-transfer (RAFT) polymerization is used for the production of the polymeric backbone, as well as for the grafts, which were installed using a grafting-from approach. A combination of N-isopropyl acrylamide and a Boc-protected primary amine-containing acrylamide was used in different compositions. After deprotection, polymers featuring different charge densities were obtained in both linear and bottle brush topologies. Antimicrobial activity was tested against three clinically relevant bacterial strains, and growth inhibition was significantly increased for bottle brush copolymers. Blood compatibility investigations revealed strong hemagglutination for linear copolymers and pronounced hemolysis for bottle brush copolymers. However, one bottle brush copolymer with a 50% charge density revealed strong antibacterial activity and negligible in vitro blood toxicity (regarding hemolysis and hemagglutination tests) resulting in selectivity values as high as 320. Membrane models were used to probe the mechanism of shown polymers that was found to be based on membrane disruption. The trends from bioassays are accurately reflected in model systems indicating that differences in lipid composition might be responsible for selectivity. However, bottle brush copolymers were found to possess increased cytotoxicity against human embryonic kidney (HEK) cells compared with linear analogues. The introduced synthetic platform enables screening of further, previously inaccessible parameters associated with the bottle brush topology, paving the way to further improve their activity profiles.

Comparing In Vitro Faecal Fermentation Methods as Surrogates for Phage Therapy Application

The human microbiome and its importance in health and disease have been the subject of numerous research articles. Most microbes reside in the digestive tract, with up to 10¹² cells per gram of faecal material found in the colon. In terms of gene number, it has been estimated that the gut microbiome harbours >100 times more genes than the human genome. Several human intestinal diseases are strongly associated with disruptions in gut microbiome composition. Less studied components of the gut microbiome are the bacterial viruses called bacteriophages that may be present in numbers equal to or greater than the prokaryotes. Their potential to lyse their bacterial hosts, or to act as agents of horizontal gene transfer makes them important research targets. In this study in vitro faecal fermentation systems were developed and compared for their ability to act as surrogates for the human colon. Changes in bacterial and viral composition occurred after introducing a high-titre single phage preparation both with and without a known bacterial host during the 24 h-long fermentation. We also show that during this timeframe 50 mL plastic tubes can provide data similar to that generated in a sophisticated faecal fermenter system. This knowledge can guide us to a better understanding of the short-term impact of bacteriophage transplants on the bacteriomes and viromes of human recipients.

Antibiotic resistant bacteria: A bibliometric review of literature

Antibiotic-resistant bacteria (ARB) are a serious threat to the health of people and the ecological environment. With this problem becoming more and more serious, more countries made research on the ARB, and the research number has been sharply increased particularly over the past decade. Therefore, it is quite necessary to globally retrace relevant researches on the ARB published from 2010 to 2020. This will help researchers to understand the current research situation, research trends and research hotspots in this field. This paper uses bibliometrics to examine publications in the field of ARB from 2010 to 2020 that were retrieved from the Web of Science (WOS). Our study performed a statistical analysis of the countries, institutions, journals, authors, research areas, author keywords, Essential Science Indicators (ESI) highly cited papers, and ESI hotspots papers to provide an overview of the ARB field as well as research trends, research hotspots, and future research directions in the field. The results showed that the number of related studies is increasing year by year; the USA is most published in the field of ARB; China is the most active in this field in the recent years; the Chinese Acad Sci published the most articles; Sci. Total Environ. published the greatest number of articles; CM Manaia has the most contributions; Environmental Sciences and Ecology is the most popular research area; and "antibiotic resistance," "antibiotics," and "antibiotic resistance genes" were the most frequently occurring author keywords. A citation analysis showed that aquatic environment-related antibiotic resistance is a key research area in this field, while antimicrobial nanomaterial-related research is a recent popular topic.

Bacteria-Adhesive Nitric Oxide-Releasing Graphene Oxide Nanoparticles for MRPA-Infected Wound Healing Therapy

A bacteria-infected wound can lead to being life-threatening and raises a great economic burden on the patient. Here, we developed polyethylenimine 1.8k (PEI_1.8k) surface modified NO-releasing polyethylenimine 25k (PEI_25k)-functionalized graphene oxide (GO) nanoparticles (GO-PEI_25k/NO-PEI_1.8k NPs) for enhanced antibacterial activity and infected wound healing via binding to the bacterial surface. In vitro antibacterial activity and in vivo wound healing efficacy in an infected wound model were evaluated compared with NO-releasing NPs (GO-PEI_25k/NO NPs). Surface modification with PEI_1.8k can enhance the ability of nanoparticles to adhere to bacteria. GO-PEI_25k/NO-PEI_1.8k NPs released NO in a sustained manner for 48 h and exhibited the highest bactericidal activity (99.99% killing) against methicillin-resistant Staphylococcus aureus (MRSA) and multidrug-resistant Pseudomonas aeruginosa (MRPA) without cytotoxicity to L929 mouse fibroblast cells at 0.1 mg/mL. In the MRPA-infected wound model, GO-PEI_25k/NO-PEI_1.8k NPs showed 87% wound size reduction while GO-PEI_25k/NO NPs showed 23% wound size reduction at 9 days postinjury. Masson trichrome and hematoxylin and eosin staining revealed that GO-PEI_25k/NO-PEI_1.8k NPs enhanced re-epithelialization and collagen deposition, which are comparable to healthy mouse skin tissue. GO-PEI_25k/NO-PEI_1.8k NPs hold promise as effective antibacterial and wound healing agents.

Determining the Antibiofilm Efficacy of Oregano Gel in an Ex Vivo Model of Percutaneous Osseointegrated Implants

Biofilm contamination is common in patients with percutaneous osseointegrated (OI) implants, leading to frequent infections, irritation, and discomfort. Reported infection rates soar up to 65% as the recalcitrant nature of biofilms complicates treatment. There is persistent need for therapies to manage biofilm burden. In response, we formulated and tested oregano essential oil in a topical gel as a potential biofilm management therapy. We developed an ex vivo system based on an established ovine OI implant model with Staphylococcus aureus ATCC 6538 biofilms as initial inocula. Gel was administered to the samples across a period of five days. Samples were quantified and colony forming unit (CFU) counts were compared against a positive control (initial bacterial inocula without treatment). Significant biofilm reduction was observed in samples treated with oregano gel compared to controls, demonstrating the potential of an oregano oil-based gel as a biofilm management therapy at the skin-implant interface of percutaneous OI implants.

Combination of Meropenem and Zinc Oxide Nanoparticles; Antimicrobial Synergism, Exaggerated Antibiofilm Activity, and Efficient Therapeutic Strategy against Bacterial Keratitis

Pseudomonas aeruginosa is an opportunistic gram-negative human pathogen that causes a wide range of infections, including nosocomial infections. Aside from the intrinsic and acquired antimicrobial resistance against many classes of antibiotics, P. aeruginosa can produce an extracellular polymeric matrix called "biofilm" that protects bacteria from antibiotics and harmful factors. Biofilm enables P. aeruginosa to develop chronic infections. This study assessed the inhibitory action of ZnO-nanoparticles against biofilms formed by multidrug-resistant P. aeruginosa strains. A collection of 24 clinical strains of P. aeruginosa were tested for their antimicrobial resistance against different antibiotics using the disk diffusion method. The antibiofilm activity of ZnO-NPs was assessed using the microtiter plate biofilm assay. The application of ZnO-NPs dramatically modulated the resistance profile and biofilm activity of P. aeruginosa. The combination of ZnO-NPs and meropenem showed synergistic antipseudomonal activity with lower MICs. The scanning electron microscope (SEM) micrographs revealed complete inhibition of biofilms treated with the meropenem-ZnO-NPs combination. Reduced expression of biofilm regulating genes lasR, pslA, and fliC was detected, reflecting the enhanced antibiofilm effect of ZnO-NPs. In vivo application of this antimicrobial mixture completely cured P. aeruginosa-induced keratitis in rats. Our findings represent a dual enhancement of antibacterial and antibiofilm activity via the use of meropenem-ZnO-NPs combination against carbapenem-resistant P. aeruginosa infections.

Antibiotic prescribing amongst South African general practitioners in private practice: an analysis of a health insurance database

Objectives

To investigate the appropriateness of antibiotic prescribing among GPs in the private primary healthcare sector in South Africa.

Methods

An anonymized national database of claims for antibiotic prescriptions was obtained from a large medical insurer. Antibiotic prescriptions were categorized based on International Classification of Diseases (ICD-10) codes as ‘appropriate’, ‘potentially appropriate’ and ‘inappropriate’ using a classification scheme developed by Chua et al. (BMJ 2019; 364: k5092). Further assessments of antibiotic choice, dosage and duration of treatment were carried out to determine the appropriateness of ‘appropriate’ and ‘potentially appropriate’ prescriptions in comparison with treatment guidelines.

Results

In February 2018, 188 141 antibiotics were prescribed for 174 889 patients who consulted GPs in the private sector. Penicillins were the most frequently prescribed antibiotic class, making up 40.7% of all antibiotics prescribed. Amoxicillin/clavulanic acid was the most frequently prescribed antibiotic, making up 28.6% of all antibiotics prescribed. Diseases of the respiratory system generated the highest number of prescriptions, making up 46.1% of all diagnoses. Of all prescriptions, 8.8% were appropriate, 32.0% were potentially appropriate, 45.4% were inappropriate and 13.8% could not be assessed. Of the appropriately and potentially appropriately prescribed antibiotics, 30.8% were correct antibiotic selections. Of the correctly selected antibiotics for adults, 57.7% had correct doses. Of the antibiotics prescribed with correct doses for adults, 76.7% had correct dosage frequencies and durations of treatment.

Conclusions

The study revealed that antibiotics were frequently prescribed inappropriately by GPs in the private primary healthcare sector. There is thus a need to develop stewardship interventions in the sector.

3D printed scaffold for repairing bone defects in apical periodontitis

Objectives

To investigate the feasibility of the 3D printed scaffold for periapical bone defects.

Methods

In this study, antimicrobial peptide KSL-W-loaded PLGA sustainable-release microspheres (KSL-W@PLGA) were firstly prepared followed by assessing the drug release behavior and bacteriostatic ability against Enterococcus faecalis and Porphyromonas gingivalis. After that, we demonstrated that KSL-W@PLGA/collagen (COL)/silk fibroin (SF)/nano-hydroxyapatite (nHA) (COL/SF/nHA) scaffold via 3D-printing technique exhibited significantly good biocompatibility and osteoconductive property. The scaffold was characterized as to pore size, porosity, water absorption expansion rate and mechanical properties. Moreover, MC3T3-E1 cells were seeded into sterile scaffold materials and investigated by CCK-8, SEM and HE staining. In the animal experiment section, we constructed bone defect models of the mandible and evaluated its effect on bone formation. The Japanese white rabbits were killed at 1 and 2 months after surgery, the cone beam computerized tomography (CBCT) and micro-CT scanning, as well as HE and Masson staining analysis were performed on the samples of the operation area, respectively. Data analysis was done using ANOVA and LSD tests. (α = 0.05).

Results

We observed that the KSL-W@PLGA sustainable-release microspheres prepared in the experiment were uniform in morphology and could gradually release the antimicrobial peptide (KSL-W), which had a long-term antibacterial effect for at least up to 10 days. HE staining and SEM showed that the scaffold had good biocompatibility, which was conducive to the adhesion and proliferation of MC3T3-E1 cells. The porosity and water absorption of the scaffold were (81.96 ± 1.83)% and (458.29 ± 29.79)%, respectively. Histological and radiographic studies showed that the bone healing efficacy of the scaffold was satisfactory.

Conclusions

The KSL-W@PLGA/COL/SF/nHA scaffold possessed good biocompatibility and bone repairing ability, and had potential applications in repairing infected bone defects.

Clinical significance The 3D printed scaffold not only has an antibacterial effect, but can also promote bone tissue formation, which provides an alternative therapy option in apical periodontitis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12903-022-02362-4.

Bacteriophage and endolysin engineering for biocontrol of food pathogens/pathogens in the food: recent advances and future trends

Despite advances in modern technologies, various foodborne outbreaks have continuously threatened the food safety. The overuse of and abuse/misuse of antibiotics have escalated this threat due to the prevalence of multidrug-resistant (MDR) pathogens. Therefore, the development of new methodologies for controlling microbial contamination is extremely important to ensure the food safety. As an alternative to antibiotics, bacteriophages(phages) and derived endolysins have been proposed as novel, effective, and safe antimicrobial agents and applied for the prevention and/or eradication of bacterial contaminants even in foods and food processing facilities. In this review, we describe recent genetic and protein engineering tools for phages and endolysins. The major aim of engineering is to overcome limitations such as a narrow host range, low antimicrobial activity, and low stability of phages and endolysins. Phage engineering also aims to deter the emergence of phage resistance. In the case of endolysin engineering, enhanced antibacterial ability against Gram-negative and Gram-positive bacteria is another important goal. Here, we summarize the successful studies of phages and endolysins treatment in different types of food. Moreover, this review highlights the recent advances in engineering techniques for phages and endolysins, discusses existing challenges, and suggests technical opportunities for further development, especially in terms of antimicrobial agents in the food industry.

Cyclic Analogs of Desferrioxamine E Siderophore for 68Ga Nuclear Imaging: Coordination Chemistry and Biological Activity in Staphylococcus aureus

As multidrug-resistant bacteria are an emerging problem and threat to humanity, novel strategies for treatment and diagnostics are actively sought. We aim to utilize siderophores, iron-specific strong chelating agents produced by microbes, as gallium ion carriers for diagnosis, applying that Fe(III) can be successfully replaced by Ga(III) without losing biological properties of the investigated complex, which allows molecular imaging by positron emission tomography (PET). Here, we report synthesis, full solution chemistry, thermodynamic characterization, and the preliminary biological evaluation of biomimetic derivatives (FOX) of desferrioxamine E (FOXE) siderophore, radiolabeled with ⁶⁸Ga for possible applications in PET imaging of S. aureus. From a series of six biomimetic analogs, which differ from FOXE with cycle length and position of hydroxamic and amide groups, the highest Fe(III) and Ga(III) stability was determined for the most FOXE alike compounds–FOX 2-4 and FOX 2-5; we have also established the stability constant of the Ga-FOXE complex. For this purpose, spectroscopic and potentiometric titrations, together with the Fe(III)–Ga(III) competition method, were used. [⁶⁸Ga]Ga-FOXE derivatives uptake and microbial growth promotion studies conducted on S. aureus were efficient for compounds with a larger cavity, i.e., FOX 2-5, 2-6, and 3-5. Even though showing low uptake values, Fe-FOX 2-4 seems to be also a good Fe-source to support the growth of S. aureus. Overall, proposed derivatives may hold potential as inert and stable carrier agents for radioactive Ga(III) ions for diagnostic medical applications or interesting starting compounds for further modifications.

In this work, the authors have investigated a set of novel ferrioxamine E analogs as potential Ga-68 chelators and tools for infection imaging.

Bacterial lysates (OM-85 BV): a cost-effective proposal in order to contrast antibiotic resistance

Background

Chronic Obstructive Pulmonary Disease (COPD) is one of the most frequent pathologies in which antibiotics are used because 50% of the exacerbations are attributable to a bacterial infection. The aims of our study were: i) to perform a meta-analysis on the efficacy of the bacterial lysate OM-85 BV in preventing acute exacerbations in patients with COPD; ii) to evaluate whether this preventive treatment can lead to significant savings for the National Health Service (NHS).

Methods

A systematic research was conducted in the electronic database MEDLINE (PubMed) in June 2017-July 2020, collecting evidences without time restrictions. Only randomized controlled trials (RCTs) were included. The keywords used were “OM 85 BV AND chronic bronchitis” and “OM 85 BV AND COPD”. A cost-effectiveness analysis (CEA) was performed considering the costs for a treatment with OM-8BV, the costs for the treatment of an acute exacerbation and the number of prevented exacerbations.

Results

59 publications were found, but the meta-analysis was conducted on 13 studies that met the inclusion criteria. OM-85 BV is responsible of a statistically significant reduction in the mean number of COPD exacerbations (p < 0.01; WMD = -0.86; CI 95%: -1.38, -0.34) and in the days of antibiotic therapy (p < 0.01; WMD = -9.49; CI 95%: -11.93, -7.05). The cost-effectiveness ratio with a negative value is in favor to treatment.

Conclusions

OM-85 BV is effective in reducing exacerbations, and could lead to significant savings for the NHS. Moreover, reducing the number of exacerbations it could avoid an over-use of antibiotics and the consequent antibiotic resistance.

Fecal Microbiome and Resistome Profiling of Healthy and Diseased Pakistani Individuals Using Next-Generation Sequencing

In this paper, we aimed to characterize the fecal microbiome and its resistomes of healthy and diseased subjects infected with multidrug-resistant Escherichia coli using next-generation sequencing (NGS). After initial screening, 26 stools samples belonging to healthy (n = 13) and diseased subjects (n = 13) were selected and subjected to NGS. A total of 23 and 42 antibiotic-resistant genes (ARGs) conferring resistance to 6 and 9 classes of antibiotics were identified in the resistomes of healthy and diseased subjects, respectively. Bacteroidetes were found to be the major phylum in both healthy and diseased subjects; however, Proteobacteria was predominantly present in the diseased subjects only. Microbial dysbiosis and predominance of various ARGs in the resistome of diseased subjects reflect the excessive usage of antibiotics in Pakistan and warrants immediate attention to regulate the use of various antimicrobials.

Development of Antimicrobial Phototreatment Tolerance: Why the Methodology Matters

Due to rapidly growing antimicrobial resistance, there is an urgent need to develop alternative, non-antibiotic strategies. Recently, numerous light-based approaches, demonstrating killing efficacy regardless of microbial drug resistance, have gained wide attention and are considered some of the most promising antimicrobial modalities. These light-based therapies include five treatments for which high bactericidal activity was demonstrated using numerous in vitro and in vivo studies: antimicrobial blue light (aBL), antimicrobial photodynamic inactivation (aPDI), pulsed light (PL), cold atmospheric plasma (CAP), and ultraviolet (UV) light. Based on their multitarget activity leading to deleterious effects to numerous cell structures-i.e., cell envelopes, proteins, lipids, and genetic material-light-based treatments are considered to have a low risk for the development of tolerance and/or resistance. Nevertheless, the most recent studies indicate that repetitive sublethal phototreatment may provoke tolerance development, but there is no standard methodology for the proper evaluation of this phenomenon. The statement concerning the lack of development of resistance to these modalities seem to be justified; however, the most significant motivation for this review paper was to critically discuss existing dogma concerning the lack of tolerance development, indicating that its assessment is more complex and requires better terminology and methodology.

Prevalence of antimicrobial use in a tertiary academic hospital: a venue for antimicrobial stewardship programs

OBJECTIVE

To quantify antimicrobial use in inpatients setting as part of antimicrobial stewardship program surveillance.

METHOD

Antimicrobial use was obtained using a pre-designed data collection form in this point prevalence study. Setting: The study was conducted in a tertiary academic hospital in the North of Jordan on 13 August 2018. Main outcome measures: antimicrobial use was determined using two methods: defined daily use (DDD) and days of therapy (DOT).

RESULTS

This study identified antimicrobial use in 144 patients. Carbapenems, glycopeptides, and piperacillin-tazobactam were the most utilized antimicrobials in the inpatients' setting in both measures DDD and DOT. The highest prescription rate of antibiotics was in the internal medicine wards (49.8 DDD/100 admissions), followed by surgery wards (33.2 DDD/100 admissions) and intensive care unit (20.6 DDD/100 admissions).

CONCLUSION

This surveillance study addressed patterns of antimicrobial usage in inpatients settings in a tertiary care hospital in Jordan. This practice is feasible and could be adopted routinely by antimicrobial stewardship programs.

Supramolecular self-assembled drug delivery system (SADDs) of vancomycin and tocopherol succinate as an antibacterial agent: in vitro, in silico and in vivo evaluations

In this study self-assembled drug delivery system (SADDs) composed of a hydrophobic d-α-tocopherol succinate (TS) and a hydrophilic vancomycin (VCM) were formulated, and its potential for enhancing the antibacterial activity of VCM against Staphylococcus aureus (SA) and Methicillin-resistant Staphylococcus aureus (MRSA) were explored. The SADDs were synthesized via supramolecular complexation, then characterized for in silico, in vitro and in vivo studies. In silico studies confirmed the self-assembly of VCM/TS into NPs. The size, surface charge and drug loading of the SADDs was ˂100 nm, -27 mV and 68%, respectively. The SADDs were non-hemolytic and biosafe. A sustained release of VCM from SADDs was noted, with 52.2% release after 48 hr. The in vitro antibacterial test showed a twofold decrease in Minimum inhibitory concentration (MIC) against SA and MRSA, and a significantly higher reduction in MRSA biofilms compared to bare VCM. Further, in silico studies confirmed strong and stable binding of TS to MRSA efflux pumps. The in vivo study using mice skin infection models showed a 9.5-fold reduction in bacterial load after treatment with SADDs, in comparison with bare VCM. These findings affirmed that VCM/TS NPs as a promising novel nano-delivery for treating bacterial infections.

Two IncHI2 Plasmid-Mediated Colistin-Resistant Escherichia coli Strains from the Broiler Chicken Supply Chain in Zhejiang Province, China

ABSTRACT

Colistin is used as one of the last-resort drugs against lethal infections caused by carbapenem-resistant pathogens of the Enterobacteriaceae family. Enterobacteriaceae bacteria carrying the mcr-1 colistin resistance gene are emerging in livestock and poultry, posing a serious threat to human health. However, there have been few reports about the prevalence and transmission of mcr-1 along the regional chicken supply chain. In this study, the complete sequences of mcr-1-positive Escherichia coli ST2705 and ST206 isolates obtained by screening 129 chilled chicken samples and 251 chicken fecal samples were investigated. Both of these isolates showed resistance to colistin, and importantly, the complete sequence of the mcr-1-positive E. coli ST2705 in China was reported for the first time. The mcr-1 gene was located on the IncHI2 plasmids pTBMCR421 (254,365 bp) and pTBMCR401 (230,964 bp) in strains ECCNB20-2 and ECZP248, respectively. Comparative analysis of mcr-1-bearing IncHI2 plasmids showed a marked similarity, indicating that these plasmids are very common and have the ability to be efficient vehicles for mcr-1 dissemination among humans, animals, and food. Furthermore, an insertion (ISKpn26) in Tn6330 (ISApl1-mcr-1-pap2-ISApl1) was identified in the plasmid pTBMCR401 and then compared; this insertion might affect the adaptability and stability of Tn6330. Taken together, these findings suggest that the IncHI2 plasmid might be a main factor affecting the transmission of mcr-1 in the chicken supply chain and that the genetic context of the mcr-1-bearing IncHI2 plasmid is constantly evolving.

HIGHLIGHTS

Label-Free Electrochemical Microfluidic Chip for the Antimicrobial Susceptibility Testing

The emergence and spread of antibiotic-resistant bacteria is a global threat to human health. An accurate antibiotic susceptibility test (AST) before initiating the treatment is paramount in the treatment and bacterial resistance control. However, the current AST methods either are complex, use chemical and biological labels, lack multiplexing, are expensive, or are too slow to be used for routine screening. The primary objective of the current study is to develop an automated electrochemical microfluidic chip (EMC) for simple and rapid AST. The microfluidic channels and gold microelectrodes were designed for the automation of antibiotic mixing and distribution in multiple test chambers and for electrical signal measurements. The designed chip was tested for AST with E. coli samples, and the results were compared with conventional broth microdilution. The presented EMC provided rapid bacterial count and AST in 170 and 150 min, respectively, while the conventional broth microdilution evaluates in 450 and 240 min, respectively. The rapid AST capability of the EMC was further demonstrated with the artificial urine samples, and the results were obtained in 270 min, which was 90 min faster than the broth microdilution method. Additionally, the minimum inhibitory concentration (MIC) was evaluated on the EMC and compared with the results from an AlamarBlue assay. The experimental results indicate the sensitivity of the chip, minimum loss of antibiotics, and eventually, reduction in the evolution of antibiotic resistance. Cumulatively, we have developed an automated, label-free, economical, rapid, robust, and user-friendly EMC for the evaluation of AST in urine samples.

Five-year change of prevalence and risk factors for infection and mortality of carbapenem-resistant Klebsiella pneumoniae bloodstream infection in a tertiary hospital in North China

BACKGROUND

There are few studies focused on carbapenem-resistant Klebsiella pneumoniae (CRKP) bloodstream infection (BSI). The aim of this study is to identify the prevalence and risk factors for infection and mortality of CRKP BSI.

METHODS

Susceptibility of Klebsiella pneumoniae (KP) isolated from blood samples and the proportion of CRKP were recorded annually. One hundred sixty-four patients with CRKP and 328 with carbapenem-susceptible Klebsiella pneumoniae (CSKP) BSI were categorized as the case group and control group to identify risk factors for CRKP infection and mortality by univariable analysis and multivariable logistic-regression analysis.

RESULTS

The proportion and mortality of CRKP BSI increased significantly, with the percentage of KP in BSI increasing from 7 to 12% from 2014 to 2019 with a concomitant resistance to meropenem increasing from 16.7 to 41.8%. Compared with CSKP group, patients in CRKP group had longer hospitalization time before bacteremia (median 14 vs 4, P < 0.001) and longer total hospitalization time (median 31 vs 19, P < 0.001). The proportion of admission to ICU was higher (70.7% vs 17.7%, P < 0.001), and APACHE II score was higher (median 12 vs 8, P < 0.001). The mortality in CRKP group was 43.9% (72/164), while 14.9% (49/328) in CSKP group (p < 0.001). KP detection in other sites(P = 0.036, OR 1.964), blood purification(P = 0.018, OR 3.326), bronchoscopy(P = 0.011, OR 5.423), surgery (P = 0.001, OR 3.084), carbapenem use(P = 0.001, OR 3.395), tigecycline use(P = 0.006, OR 4.595) were independent risk factors for CRKP BSI. Previous hospitalization (P = 0.048, OR 2.755), long hospitalization (P = 0.003, OR 1.035), bone marrow puncture (P = 0.037, OR3.856), use of β-lactamase inhibitor (P = 0.005, OR 3.890) were independent risk factors for mortality in CRKP BSI.

CONCLUSION

The prevalence and mortality of CRKP BSI are still increasing. Timely treatment of KP infection in other site, strengthening the hospital infection control of blood purification, bronchoscopy and surgery, control the use of carbapenem and tigecycline, may help to prevent CRKP BSI. More preventative hospital resources are needed for severely ill patients with prolonged hospitalizations and intensive care.

Phylogenetic analysis and screening of antimicrobial and cytotoxic activities of culturable bacteria associated with the ascidian Botryllus schlosseri

AIMS

Isolating culturable bacteria associated with ascidian (Botryllus schlosseri) and investigating their bioactivities to discover new marine microbial resources with potential to produce novel bioactive natural products.

METHODS AND RESULTS

A total of 357 bacteria were isolated from the ascidian B. schlosseri from the coast of Weihai in the north Yellow Sea, China. Of these, 203 isolates were identified by 16S rRNA gene sequencing and they belonged to 52 genera from 30 families in five phyla. The antimicrobial activities and cytotoxic activities of all isolates were determined. Of the 357 isolates, 135 isolates demonstrated antimicrobial activities, and the crude extracts of five isolates showed strong cytotoxicity against human hepatocellular carcinoma Bel 7402 or human cervical carcinoma HeLa cells.

CONCLUSIONS

Our study revealed the diversity of bacteria associated with the ascidian B. schlosseri and reported a broad spectrum of antimicrobial and cytotoxic activities displayed by these isolates.

SIGNIFICANCE AND IMPACT OF THE STUDY

Our results suggest that the culturable bacteria associated with the ascidian B. schlosseri may be a potential source for novel bioactive compounds.

High-throughput method for Antibiotic Susceptibility Testing based on Fluorescein Quenching by Bacteria: Application to Urinary Tract Infection

We recently reported a sugar-induced bacterial release of 13-Docosenamide and its ability to quench fluorescein. This simple handle to monitor bacterial growth is readily applicable to develop a quicker antibiotic sensitivity testing method along with a low-cost field-use optical instrumentation. Conditions were standardized to perform this new procedure in the most preferred and CLSI-recommended microdilution format in 12-well strips. A simple and portable optoelectronic prototype was used to capture the image and read the fluorescence signal of the culture medium of the 12-well strips. This new Fluorescence Quenching Method along with the device enabled the choice of the right antibiotic within 8 h of sample collection from the patient. It was compliant to the Clinical Laboratory Standard Institute’s quality control guidelines. Clinical assessment of the method using 440 urine samples from Urinary Tract Infection patients against 21 routinely used antibiotics showed a 94.3% match with the results of the Standard Disk Diffusion method. This new method saves the precious time taken for and the cost of antibiotic susceptibility testing for quicker and effective treatment with better compliance.

l-aspartic acid promotes fish survival against Vibrio alginolyticus infection through nitric oxide-induced phagocytosis

Bacterial infection severely impairs aquaculture development throughout the world. Despite the use of antibiotics to control bacterial infection, few other options are available especially in the area of complex ecosystem and various types of fish. In search for novel approaches in controlling bacterial infection, we adopt zebrafish, Danio reiro, as infection host and the bacteria, Vibrio alginolyticus, as pathogen to explore potential metabolites that boost host's capability to eliminate bacterial infection. By comparing the metabolome of dying fish, l-aspartic acid is a metabolite of differential abundance between the dying fish and surviving fish upon Vibrio alginolyticus infection. Exogenous l-aspartic acid increases fish survival rate from 46.67% to 76.67%. We further demonstrated that l-aspartic acid drives the production of nitrogen oxide that promotes phagocytosis. Whereas the inhibition of nitrogen oxide synthase would abolish l-aspartic acid-triggered phagocytosis as well as in vivo protective ability to V. alginolyticus. The importance of nitrogen oxide production in fish survival is also consistent with the observation in the dying fish that showed increased urea production but not nitrogen oxide. Thus, our results exemplify a novel approach in promoting fish survival in an eco-friendly way.

Patterns of self-medication with antibiotics in Maputo City: a qualitative study

Background

Mozambique classifies but does not yet enforce antibiotics as prescription-only-medicine (POM) allowing the public access to a variety of antibiotics that otherwise are provided on prescription. This contributes to the growing practice of self-medication with antibiotics (SMA) which systematically exposes individuals to the risk of developing antibiotic resistance, antibiotic side effects and increases the health service costs and morbidity. This study aimed at describing the patterns of SMA among Maputo city pharmacy customers.

Methods

A qualitative study conducted between October 2018 and March 2019 was developed with thirty-two pharmacy customers and seventeen pharmacists. Using convenience sampling, customers were recruited after buying antibiotics without prescription from nine private pharmacies. Of the thirty-two participants, twenty participated in in-depth interviews and twelve in two focus groups discussions (FGD) with six participants each. Purposive sampling and a snowball technique were used to recruit pharmacists. The transcripts were coded and analyzed using latent content analysis. Nvivo 11 was used to store and retrieve the data. The COREQ (Tong, 2007) checklist for interviews and FGD was performed.

Results

Customers admitted practices of SMA, pharmacists admitted dispensing a variety of antibiotics without prescription. Non-prescribed antibiotics (NPA) were obtained through five different patterns including; using the generic name, describing the physical appearance and using empty package, describing symptoms or health problem to pharmacists, using old prescriptions and sharing antibiotics with family, friends, and neighbors.

Conclusion

Different patterns of SMA are contributing to the indiscriminate use of antibiotics among customers. The NPA utilization is perceived as an expression of self-care where participants experience self-perceived symptoms and indulge in self-treatment as a method of caring for themselves. Moreover, antibiotics are mostly used to treat diseases that do not necessarily need antibiotics. Strong and effective public health education and promotion initiatives should be implemented to discourage inappropriate utilization of antibiotics and SMA practices.

Antimicrobial resistance and molecular genotyping of Salmonella enterica serovar Enteritidis clinical isolates from Guizhou province of Southwestern China

Salmonella enterica serovar Enteritidis (S. Enteritidis) is the most common and essential serotype that causes salmonellosis in Guizhou province. This study aimed to investigate the antimicrobial resistance (AMR) and molecular genotyping of 79 S. Enteritidis clinical isolates from 2011 to 2016 in Guizhou, China. Antimicrobial resistance and minimum inhibitory concentrations (MICs) of S. Enteritidis clinical isolates were detected by micro broth dilution method against ten classes 16 antimicrobial agents, and molecular genotyping were examined by pulsed-field gel electrophoresis (PFGE) and multiple-locus variable-number tandem repeat analysis (MLVA). All (100%) isolates showed resistance to at least one antimicrobial. Resistance to nalidixic acid (98.7%) was the highest, followed by sulfamethoxazole (87.3%) and ampicillin (77.2%). The majority of isolates (92.4%) showed decreased susceptibility to ciprofloxacin. Resistance to the third and fourth-generation cephalosporins was observed. Twenty-six AMR profiles were observed, and the predominant AMR profile was ampicillin-streptomycin-sulfamethoxazole-amoxicillin/clavulanic acid-nalidixic acid. A high burden of multidrug resistance (MDR) (81.0%) was found. Seventy-nine S. Enteritidis isolates were divided into 33 different pulsotypes (PTs), and the most frequent PT was PT18. Twenty-six different MLVA types (MTs) were generated with seven VNTR loci analysis of these isolates. The dominant PTs and MTs were persistent during 2011-2016. S. Enteritidis clinical isolates showed higher genetic diversity using PFGE combined with MLVA grouped into 60 PT-MT genotypes. No correlation was observed between genotypes, AMR profiles and geographic location. These data revealed the characteristics of AMR and molecular genotyping of S. Enteritidis clinical isolates in Guizhou province. These results highlight that strengthening the AMR and molecular genotyping surveillance is essential to prevent and control salmonellosis in Guizhou. PFGE combined with MLVA should be powerful tools for the molecular genotyping of S. Enteritidis isolates.

Risk factors for carbapenem-resistant Klebsiella pneumoniae infection: A meta-analysis

OBJECTIVES

Rates of nosocomial infections caused by carbapenem-resistant Klebsiella pneumoniae (CRKP) have increased. A meta-analysis was conducted to explore risk factors for CRKP infection in order to provide a theoretical basis for reducing the CRKP infection rate and actively preventing CRKP infection.

METHODS

Online databases, including PubMed, EMBASE, OVID, ClinicalKey, CNKI, CBM, Wanfang Database and CHKD, were searched from inception up to 31 October 2018 for articles regarding risk factors for CRKP infection. Relevant articles were retrieved, supplemented by retrospective and manual search literature. RevMan 5.3 software was used for statistical analysis.

RESULTS

A total of 30 articles comprising 5075 cases were included in the study, of which 24 were in English and 6 were in Chinese. The results showed that age, sex and diabetes mellitus were not associated with CRKP infection. The odds ratio (95% confidence interval) of risk factors for CRKP infection were as follows: immunosuppression, 1.47 (1.14-1.90); ICU admission, 3.25 (2.36-4.47); antibiotic exposure, 2.53 (1.56-4.11); carbapenem exposure, 3.99 (2.86-5.56); quinolone exposure, 1.75 (1.38-2.22); glycopeptide exposure, 3.08 (1.93-4.91); β‑lactam/β‑lactamase inhibitor (BL/BLI) exposure, 2.28 (1.37-3.80); surgery, 1.59 (1.08-2.34); mechanical ventilation, 2.91 (1.96-4.31); central venous catheterisation, 2.93 (2.00-4.28); indwelling catheter, 2.62 (1.65-4.17); and nasogastric intubation, 2.38 (1.22-4.62).

CONCLUSION

Immunosuppression, ICU admission, antibiotic exposure (including carbapenems, quinolones, glycopeptides and BL/BLIs), surgery, mechanical ventilation, central venous catheterisation, indwelling catheter and nasogastric intubation were identified as risk factors for CRKP infection and should to be considered in clinical practice.

Prophylactic Palmitoylethanolamide Prolongs Survival and Decreases Detrimental Inflammation in Aged Mice With Bacterial Meningitis

Easy-to-achieve interventions to promote healthy longevity are desired to diminish the incidence and severity of infections, as well as associated disability upon recovery. The dietary supplement palmitoylethanolamide (PEA) exerts anti-inflammatory and neuroprotective properties. Here, we investigated the effect of prophylactic PEA on the early immune response, clinical course, and survival of old mice after intracerebral E. coli K1 infection. Nineteen-month-old wild type mice were treated intraperitoneally with two doses of either 0.1 mg PEA/kg in 250 μl vehicle solution (n = 19) or with 250 μl vehicle solution only as controls (n = 19), 12 h and 30 min prior to intracerebral E. coli K1 infection. The intraperitoneal route was chosen to reduce distress in mice and to ensure exact dosing. Survival time, bacterial loads in cerebellum, blood, spleen, liver, and microglia counts and activation scores in the brain were evaluated. We measured the levels of IL-1β, IL-6, MIP-1α, and CXCL1 in cerebellum and spleen, as well as of bioactive lipids in serum in PEA- and vehicle-treated animals 24 h after infection. In the absence of antibiotic therapy, the median survival time of PEA-pre-treated infected mice was prolonged by 18 h compared to mice of the vehicle-pre-treated infected group (P = 0.031). PEA prophylaxis delayed the onset of clinical symptoms (P = 0.037). This protective effect was associated with lower bacterial loads in the spleen, liver, and blood compared to those of vehicle-injected animals (P ≤ 0.037). PEA-pre-treated animals showed diminished levels of pro-inflammatory cytokines and chemokines in spleen 24 h after infection, as well as reduced serum concentrations of arachidonic acid and of one of its metabolites, 20-hydroxyeicosatetraenoic acid. In the brain, prophylactic PEA tended to reduce bacterial titers and attenuated microglial activation in aged infected animals (P = 0.042). Our findings suggest that prophylactic PEA can counteract infection associated detrimental responses in old animals. Accordingly, PEA treatment slowed the onset of infection symptoms and prolonged the survival of old infected mice. In a clinical setting, prophylactic administration of PEA might extend the potential therapeutic window where antibiotic therapy can be initiated to rescue elderly patients.

A School-Based Educational Intervention for School-Aged Children and Caregivers about Rational Use of Antibiotics in Urban Areas of Shaanxi Province: A Study Protocol for a Randomized Controlled Research

(1) Background: Antibiotic resistance is an imperative public health issue globally. Major factors that are resulting in this trend are the irrational and excessive use of antibiotics. Children account for a greater population of antibiotics use, therefore, an educational intervention on the rational use of antibiotics for children and caregivers will be beneficial. (2) Methods: A randomized controlled and parallel group study of fifth grade children and their caregivers will be evaluated in four primary schools in Baoji and Weinan of the Shaanxi Province. Two primary schools will be randomly selected for the educational intervention and two schools will serve as a control group. In the intervention arm, educational interventions will be conducted among caregivers and their children. The intervention measures include interactive training sessions, booklets, and printed or electronic educational materials that will be given to the caregivers or the school-aged children. In the control arm, no interventions will be implemented. Baseline data collected from June, 2018 and the intervention will last for three months. Knowledge-Attitude-Practice (KAP) questionnaires will be used to evaluate the caregivers’ knowledge, their attitude, and their practice. Knowledge-Retention questionnaires will be used to assess the children’s knowledge about microbes, antibiotics, and hygiene. (3) Discussion: This study is a unique comprehensive intervention targeting both children and their caregivers. We hypothesize a decrease in the irrational use of antibiotics among the studied population. Hence, this result would provide evidence for policy makers and educational departments for the implementation of similar interventions on the rational use of antibiotics.

Humanome Versus Microbiome: Games of Dominance and Pan-Biosurveillance in the Omics Universe

Global governance of pathogens such as Ebola virus and infectious diseases is central to global health, and to innovation in systems medicine. Worrisomely, the gaps in human immunity and healthcare services combined with novel pathogens emerging by travel, biotechnological advances, or the rupture of the host-species barrier challenge infectious diseases' global governance. Such biorisks and biothreats may scale up to global catastrophic biological risks (GCBRs) spatiotemporally, either as individual or as collective risks. The scale and intensity of such threats challenge current thinking on surveillance, and calls for a move toward pan-biosurveillance. New multilayered, cross-sectoral, and adaptable strategies of prevention and intervention on GCBRs should be developed, considering human hosts in entirety, and in close relationship with other hosts (plants and animals). This also calls for the "Humanome," which we introduce in this study as the totality of human subjects plus any directly dependent biological or nonbiological entities (products, constructs, and interventions). Surveillance networks should be implemented by integrating communications, diagnostics, and robotics/aeronautics technologies. Suppression of pathogens must be enforced both before and during an epidemic outbreak, the former allowing more drastic measures before the pathogens harbor the host. We propose in this expert review that microbiome-level intervention might particularly prove as an effective solution in medical and environmental scales against traditional, currently emerging, and future infectious threats. We conclude with a discussion on the ways in which the humanome and microbiome contest and cooperate, and how this knowledge might usefully inform in addressing the GCBRs, bioterrorism, and associated threats in the pursuit of pan-biosurveillance.

Dominant serotype distribution and antimicrobial resistance profile of Shigella spp. in Xinjiang, China

Shigella represents one of the major diarrhea-inducing pathogens threatening public health, but its prevalence and antimicrobial resistance profile in Xinjiang Uygur Autonomous region, China, remains unclear. We conducted comprehensive investigation of Shigella serotype distribution and antimicrobial resistance pattern in Xinjiang, identifying 458 Shigella isolates between 2008 to 2014. Shigella flexneri was identified as predominant species, and several S. flexneri serotypes were isolated, including atypical serotypes 1c, 2c, and 4s. Dominant S. flexneri serotypes were 2a, 1b, 2b, and Xv, different from those generally dominant in China. A hybrid serotype pattern was observed, which included the major Chinese serotypes (2a, Xv) and those predominant in Pakistan (1b, 2b). Shigella sonnei was shown to have a lower frequency compared with that generally observed in China, but an increasing trend of infections associated with this pathogen was observed. Furthermore, a high frequency of drug resistance and different Shigella antimicrobial resistance patterns were demonstrated as well, including very severe resistance phenotypes, such as multidrug resistance and resistance to frontline antibiotics. Seventy-five cephalosporin-resistant Shigella isolates were frequently identified with the resistance determinants that can undergo horizontal transfer, such as bla_OXA, bla_TEM, bla_CTX-M, and integrons, facilitating the development of cephalosporin resistance among Shigella subtypes. Additionally, genetic analyses demonstrated that all 86 quinolone-resistant S. flexneri isolates possess 3–4 mutation sites in quinolone resistance-determining regions, primarily contributing to their resistance to quinolone. However, S. sonnei isolates were not shown to be quinolone resistant. Co-resistance to cephalosporins and quinolones was detected in 17 S. flexneri isolates, and these isolates were additionally multidrug resistant and carried β-lactamase genes and quinolone-resistance determinants. As is demonstrated in this study, dominant serotypes of Shigella were distributed in unique trend with dangerous drug resistance patterns. Novel strategies are urgently required to prevent the development of drug resistance among diarrhea-inducing pathogens.

Distribution of ARGs and MGEs among glacial soil, permafrost, and sediment using metagenomic analysis

Antibiotic resistance genes (ARGs) and mobile genetic elements (MGEs) can be identified with metagenomic analyses comparing relatively pristine and human-impacted environments. We collected samples from 3 different environments: glacial soil little affected by anthropogenic activity, deep permafrost dated to 5821 BP (before human antibiotics), and sediment from the Pearl River. Sulfonamides, tetracyclines, and fluoroquinolones were common in the sediment samples. Sulfonamides and tetracycline were not found in permafrost; tetracycline was also not found in glacial soil. ARGs from the sediment were more abundant and diverse than those from glacial soil and permafrost. More types of resistance mechanisms were also present in the sediment. The diversity of MGEs was significantly correlated with the abundance and diversity of ARGs. The result will help future workers to better understand the distribution of ARGs among environments more or less impacted by anthropogenic activities.

Antibiotic prescribing for acute respiratory infections in children in Jordan

Background

Most acute respiratory infections (ARIs) in children are due to viral etiology; however, over-prescribing of antibiotics for ARIs is common. The aim of this investigation was to identify antibiotic prescribing prevalence for children with ARIs and to identify predictors of broad-spectrum antibiotic prescribing.

Methods

This was a prospective cross sectional study in a sample of ambulatory care settings in Jordan. Children (<18 years) presenting with ARIs were assessed in terms of patient's demographics, antibiotic prescription and clinical diagnosis. Multivariable logistic regression analysis was used to identify predictors of broad-spectrum antibiotic prescription.

Results

Antibiotics were prescribed for 78.4% (4575/5829) of children with ARIs. Antibiotic prescription for ARIs for which antibiotics are not indicated was 69.2% (2688/3883). Broad-spectrum antibiotic prescription occurred in 51.1% (2337/4575) of all antibiotic-prescribed participants. Some of the predictors of broad-spectrum antibiotic prescription were: otitis media (OR 4.93 [95% CI 3.44-7.14]), tonsillitis (OR 6.03 [95% CI 4.39-8.33]), age 0-5 years (OR 1.17 [95% CI 1.02-1.38]) compared to age 6-12 years, fever (OR 2.14 [95% CI 1.78-2.59]), outpatient setting (OR 73 [95% CI 2.17-3.42]) and military sector (OR 2.29 [95% CI 1.82-2.90]).

Conclusions

Antibiotic prescribing is high and often inappropriate. Predictors of broad-spectrum antibiotic prescribing were identified. Health policy initiatives should involve all stakeholders to minimize inappropriate antibiotic prescription and to prevent poor outcomes associated with such practice.

Investigation of antimicrobial use at a tertiary care hospital in Southern Punjab, Pakistan using WHO methodology

Background

Globally, between 20 to 50% of antimicrobial consumption is inappropriate, causing significant impact on the quality of care, cost of therapy and incidence of adverse drug reactions. The purpose of this study was to investigate the prescribing patterns and utilization of antimicrobials in ten selected wards at Bahawal Victoria Hospital (BVH), Bahawalpur, Punjab, Pakistan.

Methods

A descriptive cross-sectional study was designed using the World Health Organization (WHO) indicators for antimicrobial use. Standard data collection forms were used in ten wards and the Pharmacy Department at BVH. Antimicrobial utilization patterns in terms of frequency and percentage were also determined. Systematic random sampling techniques were used to collect data from 1,000 prescription records out of 21,115 prescriptions written for the six months January to June 2016.

Results

For the hospital indicators, a formulary list or essential medicines list (FL/EML) was available, but standard treatment guidelines (STGs) for infectious diseases was not. The average number of days that key antimicrobials were out of stock was 3.3 days per month. The expenditure on antimicrobials as a percentage of the total medicines costs was 12.2%. For the prescribing indicators, the percentage of hospitalizations with antimicrobial(s) prescribed was 82.3%, and the average number of antimicrobials per hospitalization was 1.4 (SD = 0.6). The average duration of antimicrobial treatment per hospitalization was 5.4 days (SD = 3.2). The average cost of antimicrobials prescribed per hospitalization was USD 5.4 (SD = 6.7). None of the patients who were prescribed antimicrobials, received AM according to the STGs (pneumonia and cesarean section cases). Among the patient-care and supplemental indicators, the average duration of hospital stay of patients who received antimicrobials was 6.4 (SD = 4.3) days. The drug sensitivity testing was almost non-existent, with only 0.24% prescription records having drug sensitivity tests. Ceftriaxone (39.6%), metronidazole (23.4%) and cefotaxime (23.1%) were the top most frequently prescribed antimicrobials.

Conclusions

The results of the current study revealed less than optimal antimicrobial prescribing and utilization patterns of selected wards at BVH. Continuous education and training of physicians, and cost-effective policies could play an important role in promoting the rational use of antimicrobials in this setting.

Electronic supplementary material

The online version of this article (doi:10.1186/s13756-017-0199-7) contains supplementary material, which is available to authorized users.

Wireless electrostimulation: a new approach in combating infection?

Electrostimulation (ES), hitherto successfully employed in wound treatment, has shown potential in antimicrobial applications, suggesting its use as synergistic to or replacement of antibiotics. The differential susceptibility of pathogens and host tissue and organs to various ES modalities might allow selective use against specific infections. The use of ES is cheaper in terms of development/testing, routine application and environmental footprint. If extensive substitution of chemical compounds is achieved, the development of resistance might be reversed through negative selection. A promising setup of ES seems to be the noncontact current transfer, due to low amperage similar to innate bioelectricity, painlessness, simple logistics and low risk for treatment-caused infection.

Methanol Extract from Anogeissus leiocarpus (DC) Guill. et Perr. (Combretaceae) Stem Bark Quenches the Quorum Sensing of Pseudomonas aeruginosa PAO1

Background: Due to its extensive arsenal of virulence factors and inherent resistance to antibiotics, Pseudomonas aeruginosa is a threat particularly in immunocompromised patients. Considering the central role of quorum sensing in the production of virulence factors, inhibition of bacterial communication mechanism constitute an opportunity to attenuate pathogenicity of bacteria resistant to available antibiotics. Our study aimed to assess the anti-quorum sensing activity of Anogeissus leiocarpus, traditionally used in Burkina Faso, for the treatment of infected burn wounds. Methods: Investigations were carried out on methanol extract from A. leiocarpus stem bark. The reporter strains Chromobacterium violaceum CV026 and P. aeruginosa PAO1 derivatives were used to evidence any interference with the bacterial quorum sensing and expression of related genes. P. aeruginosa PAO1 was used to measure the impact on pyocyanin production. Results: At a sub-inhibitory concentration (100 µg/mL), A. leiocarpus methanol extract quenched the quorum sensing mechanism of P. aeruginosa PAO1 by down-streaming the rhlR gene, with a subsequent reduction of pyocyanin production. Moreover, the antioxidant polyphenols evidenced are able to reduce the oxidative stress induced by pyocyanin. Conclusion: The antioxidant and anti-quorum sensing activities of A. leiocarpus stem bark could justify its traditional use in the treatment of infected burn wounds.