Antibiotic Resistance: From the Bench to Patients

The challenge of antimicrobial resistance (AMR): current status and future prospects

Antimicrobial resistance (AMR) represents a critical global threat, compromising the effectiveness of antibacterial drugs as bacteria adapt and survive exposure to many classes of these drugs. This phenomenon is primarily fueled by the widespread overuse and misuse of antibacterial drugs, exerting selective pressure on bacteria and promoting the emergence of multi-resistant strains. AMR poses a top-priority challenge to public health due to its widespread epidemiological and economic implications, exacerbated not only by the diminishing effectiveness of currently available antimicrobial agents but also by the limited development of genuinely effective new molecules. In addressing this issue, our research aimed to examine the scientific literature narrating the Italian situation in the common European context of combating AMR. We sought to delineate the current state of AMR and explore future prospects through an analysis of strategies to counter antibacterial drug resistance. Adopting the "One Health" model, our objective was to comprehensively engage diverse sectors, integrate various disciplines, and propose programs, policies, and regulations. This narrative review, based on PubMed research related to antibiotic resistance, emphasizes the urgent need for a coordinated and proactive approach at both national and European levels to mitigate the impact of AMR and pave the way for effective strategies to counter this global health challenge.

Custom-printed microfluidic chips using simultaneous ratiometric fluorescence with "Green" carbon dots for detection of multiple antibiotic residues in pork and water samples

In the evolving field of food safety, rapid and precise detection of antibiotic residues is crucial. This study aimed to tackle this challenge by integrating advanced inkjet printing technology with sophisticated microfluidic paper-based analytical devices (µPADs). The µPAD design utilized "green" quantum dots synthesized via an eco-friendly hydrothermal method using green white mulberry leaves as the carbon source, serving as the key fluorescent detection material. The action mechanism involved a photoinduced electron transfer system using red carbon dots (CDs) as electron donors and blue CDs combined with two-dimensional layered molybdenum disulfide (MoS2) nanosheets as electron acceptors. This system could quickly detect antibiotics within 10 min in pork and water samples, demonstrating high sensitivity and recovery rates: 6.5 pmol/L at 99.75%-110% for sulfadimethoxine, 3.3 pmol/L at 99%-105% for sulfamethoxazole, and 8.5 pmol/L at 98.5%-105% for tetracycline. It achieved a relative standard deviation under 5%, ensuring reliability and reproducibility. The fabricated sensor offered a promising application for the rapid and efficient on-site detection of antibiotic residues in food.

Insights into Allosteric Inhibition of the AcrB Efflux Pump: Role of Distinct Binding Pockets, Protomer Preferences, and Crosstalk Disruption

AcrB, a key component in bacterial efflux processes, exhibits distinct binding pockets that influence inhibitor interactions. In addition to the well-known distal binding pocket within the periplasmic domain, a noteworthy pocket amidst the transmembrane (TM) helices serves as an alternate binding site for inhibitors. The bacterial efflux mechanism involves a pivotal functional rotation of the TM protein, inducing conformational changes in each protomer and propelling drugs toward the outer membrane domain. Surprisingly, inhibitors binding to the TM domain display a preference for L protomers over T protomers. Metadynamics simulations elucidate that Lys940 in the TM domain of AcrB can adopt two conformations in L protomers, whereas the energy barrier for such transitions is higher in T protomers. This phenomenon results in stable inhibitor binding in l protomers. Upon a detailed analysis of unbinding pathways using random accelerated molecular dynamics and umbrella sampling, we have identified three distinct routes for ligand exit from the allosteric site, specifically involving regions within the TM domains─TM4, TM5, and TM10. To explore allosteric crosstalk, we focused on the following key residues: Val452 from the TM domain and Ala831 from the porter domain. Surprisingly, our findings reveal that inhibitor binding disrupts this communication. The shortest path connecting Val452 and Ala831 increases upon inhibitor binding, suggesting sabotage of the natural interdomain communication dynamics. This result highlights the intricate interplay between inhibitor binding and allosteric signaling within our studied system.

Screening Tests for the Interaction of Rubus idaeus and Rubus occidentalis Extracts with Antibiotics against Gram-Positive and Gram-Negative Human Pathogens

WHO (World Health Organization) reports from recent years warn about the growing number of antibiotic-resistant bacterial strains. Therefore, there is an urgent need to constantly search for new substances effective in the fight against microorganisms. Plants are a rich source of chemical compounds with antibacterial properties. These compounds, classified as secondary metabolites, may act independently or support the action of currently used antibiotics. Due to the large number of metabolites isolated from the plant kingdom and new plant species being studied, there is a need to develop new strategies/techniques or modifications of currently applied methods that can be used to select plant extracts or chemical compounds isolated from them that enter into positive, synergistic interactions with currently used antibiotics. One such method is the dual-disk synergy test (DDST). It involves the diffusion of active compounds in the agar environment and influencing the growth of microorganisms grown on it. The method was used to assess the interaction of extracts from the fruit and shoots of some cultivated varieties of Rubus idaeus and Rubus occidentalis with selected antibiotics. The research was conducted on strains of bacteria pathogenic to humans, including Staphylococcus aureus, Corynebacterium diphtheriae, Escherichia coli, Pseudomonas aeruginosa, Helicobacter pylori, and Candida albicans, showing synergy, antagonism, or lack of interaction of the tested substances-plant extract and antibiotic. As a result, it was found that the diffusion method is useful in screening tests to assess the impact of antibiotic-herbal substance interactions on Gram-positive and Gram-negative microorganisms.

Market-ready U-AST kit: simple, fast, cost-effective solution for concurrently detecting urinary tract infection and antibiotic resistance

There is an increasing demand for an inexpensive, quick, accessible, and simple method for the detection of urinary tract infection (UTI) together with the antibiotic-resistance profile of the infection-causing bacteria. Our primary goal is to assist doctors in prescribing antibiotics that will quickly treat infections and reduce the likelihood of antibiotic resistance spreading throughout the community. To this end, a urinary tract infection antibiotic-sensitivity test (U-AST) kit was developed for the validation of bacterial infection in the urinary tract and determination of the antibiotic-resistance profile of the bacteria in a short time. The U-AST kit was standardized using standard strains of bacteria, specifically Escherichia coli, Enterococcus faecalis, Pseudomonas aeruginosa, Vibrio cholerae, and Pseudomonas species. Further, the kit was validated using 50 clinical urine samples with variation in their physical and chemical parameters, and the resistance pattern against five therapeutically important antibiotics were tested. The results acquired using the U-AST kit showed a 100% similarity to those acquired using the laboratory-based gold standard method. Interestingly, the U-AST kit required a maximum of 9 h to understand the bacterial contamination and resistance profile of the bacterial community, which was observed by a simple color change. The same result can be obtained using the gold standard method but requires 36-72 h, a sophisticated microbiology method, and skilled microbiologists. Other methods can also predict infection quickly with the aid of sophisticated instrumentation; however, understanding the antibiotic-resistance pattern is not possible. To the best of our understanding, this is a unique technique for the quick, easy, and inexpensive detection of UTI with antibiotic sensitivity testing and does not require a special laboratory set-up or expert personnel. The commercialization of the developed clinically validated U-AST kit is currently underway.

Antimicrobial Peptides towards Clinical Application-A Long History to Be Concluded

Antimicrobial peptides (AMPs) are molecules with an amphipathic structure that enables them to interact with bacterial membranes. This interaction can lead to membrane crossing and disruption with pore formation, culminating in cell death. They are produced naturally in various organisms, including humans, animals, plants and microorganisms. In higher animals, they are part of the innate immune system, where they counteract infection by bacteria, fungi, viruses and parasites. AMPs can also be designed de novo by bioinformatic approaches or selected from combinatorial libraries, and then produced by chemical or recombinant procedures. Since their discovery, AMPs have aroused interest as potential antibiotics, although few have reached the market due to stability limits or toxicity. Here, we describe the development phase and a number of clinical trials of antimicrobial peptides. We also provide an update on AMPs in the pharmaceutical industry and an overall view of their therapeutic market. Modifications to peptide structures to improve stability in vivo and bioavailability are also described.

Operando investigation of the synergistic effect of electric field treatment and copper for bacteria inactivation

As the overuse of chemicals in our disinfection processes becomes an ever-growing concern, alternative approaches to reduce and replace the usage of chemicals is warranted. Electric field treatment has shown promising potential to have synergistic effects with standard chemical-based methods as they both target the cell membrane specifically. In this study, we use a lab-on-a-chip device to understand, observe, and quantify the synergistic effect between electric field treatment and copper inactivation. Observations in situ, and at a single cell level, ensure us that the combined approach has an enhancement effect leading more bacteria to be weakened by electric field treatment and susceptible to inactivation by copper ion permeation. The synergistic effects of electric field treatment and copper can be visually concluded here, enabling the further study of this technology to optimally develop, mature, and scale for its various applications in the future.

Gram-Negative ESKAPE Bacteria Surveillance in COVID-19 Pandemic Exposes High-Risk Sequence Types of Acinetobacter baumannii MDR in a Tertiary Care Hospital

The interruption of bacteriological surveillance due to the COVID-19 pandemic brought serious consequences, such as the collapse of health systems and the possible increase in antimicrobial resistance. Therefore, it is necessary to know the rate of resistance and its associated mechanisms in bacteria causing hospital infections during the pandemic. The aim of this work was to show the phenotypic and molecular characteristics of antimicrobial resistance in ESKAPE bacteria in a Mexican tertiary care hospital in the second and third years of the pandemic. For this purpose, during 2021 and 2022, two hundred unduplicated strains of the ESKAPE group (Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumannii) were collected from various clinical sources and categorized by resistance according to the CLSI. An analysis of variance (ANOVA) complemented by the Tukey test was performed to search for changes in antimicrobial susceptibility profiles during the study period. Finally, the mechanisms of resistance involved in carbapenem resistance were analyzed, and the search for efflux pumps and high-risk sequence types in A. baumannii was performed by multilocus analysis (MLST). The results showed no changes in K. pneumoniae resistance during the period analyzed. Decreases in quinolone resistance were identified in E. coli (p = 0.039) and P. aeruginosa (p = 0.03). Interestingly, A. baumannii showed increases in resistance to penicillins (p = 0.004), aminoglycosides (p < 0.001, p = 0.027), carbapenems (p = 0.027), and folate inhibitors (p = 0.001). Several genes involved in carbapenem resistance were identified (blaNDM, blaVIM, blaOXA, blaKPC, blaOXA-40, and blaOXA-48) with a predominance of blaOXA-40 and the adeABCRS efflux pump in A. baumannii. Finally, MLST analysis revealed the presence of globally distributed sequence types (ST369 and ST758) related to hospital outbreaks in other parts of the world. The results presented demonstrate that the ESKAPE group has played an important role during the COVID-19 pandemic as nosocomial antibiotic-resistant pathogens and in particular A. baumannii MDR as a potential reservoir of resistance genes. The implications of the increases in antimicrobial resistance in pathogens of the ESKAPE group and mainly in A. baumannii during the COVID-19 pandemic are analyzed and discussed.

Resistance mechanisms for Gram-negative bacteria-specific lipopeptides, turnercyclamycins, differ from that of colistin

IMPORTANCE

Bacterial resistance to antibiotics is a crisis. Acinetobacter baumannii is among the CDC urgent threat pathogens in part for this reason. Lipopeptides known as turnercyclamycins are produced by symbiotic bacteria that normally live in marine mollusks, where they may be involved in shaping their symbiotic niche. Turnercyclamycins killed Gram-negative pathogens including drug-resistant Acinetobacter, but how do the mechanisms of resistance compare to other lipopeptide drugs? Here, we define resistance from a truncation of MlaA, a protein involved in regulating bacterial membrane phospholipids. Intriguingly, this resistance mechanism only affected one turnercyclamycin variant, which differed only in two atoms in the lipid tail of the compounds. We could not obtain significant resistance to the second turnercyclamycin variant, which was also effective in an infection model. This study reveals an unexpected subtlety in resistance to lipopeptide antibiotics, which may be useful in the design and development of antibiotics to combat drug resistance.

A three-in-one nanoplatform with photo/chemodynamic activities combined with glutathione depletion for treating bacterial infections

The misuse of antibiotics leading to bacterial multidrug resistance is responsible for severe infectious diseases and a significant cause of mortality worldwide, resulting in numerous human disasters. Photodynamic antibacterial therapy (PDAT) is a promising strategy against multiantibiotic-resistant bacteria, but its antibacterial activity is greatly limited by reduced glutathione (GSH) in bacteria. In this study, we constructed a nanoplatform through the formation of metal chelating complexes (FeP) between ferric and pyrophosphate ions, with subsequent adsorption of the photosensitizer ZnPc(COOH)8 (octa-carboxyl substituted zinc phthalocyanine) mediated by polylysine (PL) on the surface. The nanocomplexes FeP@PL:ZnPc(COOH)8 exhibited the capacity of GSH depletion and chemodynamic activity, which synergistically enhanced PDAT efficacy. FeP@PL:ZnPc(COOH)8 possessed the excellent antibacterial activity in vivo and in vitro, which might be attributed to the increased production of reactive oxygen species (ROS), reduced GSH level in bacteria, improved bacterial uptake, and enhanced destruction of the bacterial outer membrane. Moreover, FeP@PL:ZnPc(COOH)8 exhibited accelerated wound healing efficacy and the ability to recognize bacteria-infected wounds, rendering it an effective theranostic nanoplatform for bacterial infections. The construction strategy of nanocomplexes in this study holds theoretical and practical significance for high-efficiency synergistic photodynamic and chemodynamic antibacterial therapy.

Antibacterial and antivirulence factor activities of protein hydrolysates from Phatthalung Sangyod rice (Oryza sativa L.) seeds against zoonotic and foodborne pathogens

Background and Aim

Antimicrobial resistance is an emerging public health threat. Foodborne illnesses are typically caused by bacteria, such as Escherichia coli, Pseudomonas aeruginosa, Bacillus cereus, and Staphylococcus aureus, which are frequently resistant to common antimicrobial agents. Rice is a staple grain in most parts of the world. Our previous work showed that Phatthalung Sangyod rice seed protein hydrolysates (SYPs), especially SYP4, exhibit antifungal activity against several fungal species that are pathogenic for both humans and animals and are non-cytotoxic to animal red blood cells. In this study, we aimed to determine the effects of the bioactive peptides in SYPs against several pathogenic bacteria in humans and animals.

Materials and Methods

After isolating SYP1, it was treated as follows: heated (SYP2), and hydrolyzed using pepsin (SYP3), and proteinase K (SYP4). Then, we used 500 μg of protein to evaluate the antibacterial effects on four pathogenic bacteria, including E. coli, P. aeruginosa, B. cereus, and S. aureus, using agar well diffusion. Using a broth microdilution assay, we determined the minimum inhibitory and bactericidal concentration (MIC and MBC, respectively) values of active SYPs. Using the agar well diffusion and microtube incubation methods, we also assessed the inhibitory effects of SYPs on the bacterial quorum sensing (QS) activity of Chromobacterium violaceum. Sangyod rice seed protein hydrolysates were evaluated for their ability to inhibit the biofilm formation of bacterial cells by a crytal violet assay. Furthermore, using the dropping method, we tested the inhibitory effects of SYPs on the bacterial pigments pyocyanin in P. aeruginosa and staphyloxanthin in S. aureus.

Results

Our results showed that the crude protein lysate (SYP1) did not exhibit antibacterial activity against any of the test bacteria. Intriguingly, after boiling (SYP2) and enzymatic hydrolysis (SYP3 and SYP4), the protein hydrolysates were transformed into bioactive peptides and displayed antibacterial properties against all of the test bacteria at a concentration of 500 μg as determined by agar well diffusion. SYP4 demonstrated the highest antibacterial activity as it completely inhibited all test strains, with inhibition zones ranging from 16.88 ± 0.25 to 21.25 ± 0.5 mm, and also yielded the highest MIC/MBC values against P. aeruginosa, B. cereus, and E. coli, at 256 and >256 μg/mL, respectively. We observed that at least 256 μg/mL of SYP4 is required to exhibit optimal antibacterial activity. At 16-128 μg/mL, it exhibited antibiofilm activity against S. aureus. Furthermore, at 256 μg/mL, SYP4 inhibited pyocyanin in P. aeruginosa and staphyloxanthin in S. aureus. Although SYP2 and SYP3 displayed weak antibacterial activity and their MIC values could not be obtained for all bacteria, they showed strong QS inhibition in C. violaceum at 256 μg protein. Moreover, SYP2 and SYP3, at a minimum concentration of 32 μg/mL, significantly reduced violacein production. SYP3 also showed biofilm reduction activity on S. aureus at least 16-512 μg/mL.

Conclusion

Sangyod Phatthalung protein hydrolysates exerted excellent inhibitory effects against the growth of bacteria and their virulence factors, such as QS, biofilm formation, and/or pigment production. These factors include zoonotic and foodborne pathogens. Therefore, daily consumption of Sangyod Phatthalung rice might reduce the risk of bacterial pathogenesis and foodborne diseases. In conclusion, functional foods or alternate methods of treating bacterial illnesses may be developed in humans and animals.

Synthesis, antimicrobial properties and in silico studies of aryloxyacetic acid derivatives with hydrazone or thiazolidine-4-one scaffold

In this work, twenty hydrazide-hydrazone and 4-thiazolidinone derivatives were synthesized starting from m-cresol. Antimicrobial evaluation was carried out by microdilution method against Enterococcus faecalis and Staphylococcus aureus as Gram-positive bacteria and Escherichia coli and Pseudomonas aeruginosa as Gram-negative bacteria, and three pathogenic fungi Candida albicans, Candida parapsilosis and Candida krusei. Some compounds possessed considerable antimicrobial properties against the tested microorganisms, particularly against E. coli. 4-Thiazolidinones containing 3-methoxyphenyl and 3,5-dichlorophenyl moieties (4h and 4i) were found to be the most active derivatives with MICs of 2 μg/mL against E. coli. N'-[(3,5-dichlorophenyl)methylidene]-2-(3-methylphenoxy)acetohydrazide (3i) also displayed antifungal activity against Candida krusei that was comparable to fluconazole. Calculated drug-likeness and ADMET parameters of the most active compounds confirmed their potential as antimicrobial drug candidates. Molecular docking investigations were carried out in the thiamine diphosphate-binding site of pyruvate dehydrogenase multienzyme complex E1 component (PDHc-E1) to clarify the potential antibacterial mechanism against E. coli. The results showed the potential and importance of developing new hydrazones and 4-thiazolidinones that would be effective against microbial strains.Communicated by Ramaswamy H. Sarma.

Recent Progress of Photothermal Therapy Based on Conjugated Nanomaterials in Combating Microbial Infections

Photothermal therapy has the advantages of non-invasiveness, low toxicity, simple operation, a broad spectrum of antibacterial ability, and non-proneness to developing drug resistance, which provide it with irreplaceable superiority in fighting against microbial infection. The effect of photothermal therapy is closely related to the choice of photothermal agent. Conjugated nanomaterials are potential candidates for photothermal agents because of their easy modification, excellent photothermal conversion efficiency, good photostability, and biodegradability. In this paper, the application of photothermal agents based on conjugated nanomaterials in photothermal antimicrobial treatment is reviewed, including conjugated small molecules, conjugated oligomers, conjugated polymers, and pseudo-conjugated polymers. At the same time, the application of conjugated nanomaterials in the combination of photothermal therapy (PTT) and photodynamic therapy (PDT) is briefly introduced. Finally, the research status, limitations, and prospects of photothermal therapy using conjugated nanomaterials as photothermal agents are discussed.

An overview of gram-negative bacteria with difficult-to-treat resistance: definition, prevalence, and treatment options

INTRODUCTION

Difficult-to-treat resistance (DTR) is a newly proposed resistance phenotype characterized by resistance to all first-line drugs. The emergence of DTR as a new resistance phenotype has significant implications for clinical practice. This new concept has the potential to be widely used instead of traditional phenotypes.

AREAS COVERED

This study carried out a detailed analysis about the definition, application, and evolution of various resistance phenotypes. We collected all the research articles on Gram-negative bacteria with difficult-to-treat resistance (GNB-DTR), analyzed the DTR in each region and each bacterial species. The advantages and doubts of DTR, the dilemma of GNB-DTR infections and the potential therapeutic strategies are summarized in the review.

EXPERT OPINION

Available studies show that the prevalence of GNB-DTR is not optimistic. Unlike traditional resistance phenotypes, DTR is more closely aligned with the clinical treatment perspective and can help with the prompt selection of an appropriate treatment plan. Currently, potential treatment options for GNB-DTR include a number of second-line drugs and novel antibiotics. However, the definition of first-line drugs is inherently dynamic. Therefore, the DTR concept based on first-line drugs needs to be continuously updated and refined, considering the emergence of new antibiotics, resistance characteristics, and pathogen prevalence in different regions.

In Vitro Investigation of the Antibacterial Activity of Salamander Skin Peptides

Given the current and future costs of antibiotic-resistant bacteria to human health and economic productivity, there is an urgent need to develop new antimicrobial compounds. Antimicrobial peptides are a promising alternative to conventional antibiotics and other antimicrobials. Amphibian skin is a rich source of bioactive compounds, but the antibacterial properties of salamander skin peptides have been neglected. Here, we examined the in vitro ability of skin peptides from 9 species of salamander representing 6 salamander families to inhibit the growth of ESKAPE pathogens, which are bacteria that have developed resistance to conventional antibiotics. We also examined whether the skin peptides caused lysis of human red blood cells. Skin peptides from Amphiuma tridactylum had the greatest antimicrobial properties, completely inhibiting the growth of all bacterial strains except for Enterococcus faecium. Likewise, skin peptides from Cryptobranchus alleganiensis completely inhibited the growth of several of the bacterial strains. In contrast, skin peptide mixtures from Ambystoma maculatum, Desmognathus fuscus, Eurycea bislineata, E. longicauda, Necturus beyeri, N. maculosus, and Siren intermedia did not completely inhibit bacterial growth even at the highest concentrations. Finally, none of the skin peptide mixtures caused lysis of human red blood cells. Together, we demonstrate that salamander skin produces peptides with potent antibacterial properties. It remains to elucidate the peptide sequences and their antibacterial mechanisms.

Epidemiology of community origin of major multidrug-resistant ESKAPE uropathogens in a paediatric population in South-East Gabon

BACKGROUND

Urinary tract infections (UTIs) in children are very common. They are often associated with a high risk of sepsis and death. In recent years, antibiotic-resistant uropathogens ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacteriaceae) are increasingly encountered in UTIs. These bacteria, usually multidrug-resistance (MDR), extensive drug-resistance (XDR), pandrug-resistance (PDR), Extended-spectrum cephalosporin-resistance (ESC), Usual Drug Resistance (UDR), Difficult-to-Treat Resistance (DTR) and Carbapenem-resistance Enterobacteriales (CRE), represent a global threat for the management of paediatric UTIs. The aim of this study was to determine the epidemiology of community origin and antibiotic sensitivity of major ESKAPE uropathogens in paediatric UTIs in South-East Gabon.

METHODS

The study involved 508 children aged 0-17 years. Identification of bacterial isolates was carried out using Vitek-2 compact automated system and the antibiogram with the disk diffusion and microdilution methods according to the European Committee on Antimicrobial Susceptibility Testing recommendations. Logistic regression analysis was used to assess the impact of patients' socio-clinical characteristics on uropathogens phenotype in both univariate and multivariate analysis.

RESULTS

The prevalence of UTIs was 59%. E. coli (35%) and K. pneumoniae (34%) were the main ESKAPE involved in UTIs followed by Enterococcus spp. (8%) and S. aureus (6%). Among major ESKAPE, DTR-E. coli (p = 0.01), CRE-E. coli (p = 0.02) and XDR-E. coli (p = 0.03), Trimethoprim-sulfamethoxazole-resistant bacteria (p = 0.03) were associated with abdomino-pelvic pain. While MDR-E. coli (p < 0.001), UDR-E. coli (p = 0.02), ESC-E. coli (p < 0.001), MDR- Enterococcus (p = 0.04), UDR- Enterococcus (p = 0.02), bacteria resistant to Ampicillin (p < 0.01), Cefotaxime (p = 0.04), Ciprofloxacin (p < 0.001), Benzylpenicillin (p = 0.03) and Amikacin (p = 0.04) were more frequent among male children. MDR-Enterococcus (p < 0.01), bacteria resistant to Amoxicillin-clavulanic acid (p = 0.03), Cefalotin (p = 0.01), Ampicillin (p = 0.02) and Gentamicin (p = 0.03) were associated with treatment failure. In addition, Trimethoprim-sulfamethoxazole-resistant bacteria (p = 0.03) was associated with recurrent UTIs while those resistant to Ciprofloxacin was associated with pollakiuria (p = 0.01) and urinary burning (p = 0.04). Furthermore, UDR-K. pneumoniae (p = 0.02) was more frequent in neonates and infants.

CONCLUSION

This study determined the epidemiology of ESKAPE uropathogens in paediatric UTIs. It found a high prevalence of paediatric UTIs associated with children's socio-clinical characteristics and diverse bacterial antibiotic resistance phenotypes.

Antibiotics and Bacterial Resistance-A Short Story of an Endless Arms Race

Despite the undisputed development of medicine, antibiotics still serve as first-choice drugs for patients with infectious disorders. The widespread use of antibiotics results from a wide spectrum of their actions encompassing mechanisms responsible for: the inhibition of bacterial cell wall biosynthesis, the disruption of cell membrane integrity, the suppression of nucleic acids and/or proteins synthesis, as well as disturbances of metabolic processes. However, the widespread availability of antibiotics, accompanied by their overprescription, acts as a double-edged sword, since the overuse and/or misuse of antibiotics leads to a growing number of multidrug-resistant microbes. This, in turn, has recently emerged as a global public health challenge facing both clinicians and their patients. In addition to intrinsic resistance, bacteria can acquire resistance to particular antimicrobial agents through the transfer of genetic material conferring resistance. Amongst the most common bacterial resistance strategies are: drug target site changes, increased cell wall permeability to antibiotics, antibiotic inactivation, and efflux pumps. A better understanding of the interplay between the mechanisms of antibiotic actions and bacterial defense strategies against particular antimicrobial agents is crucial for developing new drugs or drug combinations. Herein, we provide a brief overview of the current nanomedicine-based strategies that aim to improve the efficacy of antibiotics.

Clinical Evaluation of Meropenem-Vaborbactam Combination for the Treatment of Urinary Tract Infection: Evidence to Date

As antimicrobial resistance continues to grow, one of the biggest threats includes the members of the Enterobacterales order presenting with carbapenem resistance (CRE). Meropenem-vaborbactam, along with other beta-lactam/beta-lactamase agents, has been developed to help combat this growing concern and is currently approved to treat complicated urinary tract infections (cUTI), as well as acute pyelonephritis (AP), in the USA. Vaborbactam is a novel beta-lactamase inhibitor designed specifically to optimize and restore the activity of meropenem against resistant Enterobacterales. Vaborbactam inhibits a number of beta-lactamases, including in vitro activity against extended-spectrum beta-lactamases (ESBL) and the Klebsiella pneumoniae carbapenemase (KPC) group. KPC represents one of the most clinically relevant carbapenemase in the USA, accounting for the majority of carbapenemase-producing CRE. Meropenem-vaborbactam has been studied in the two Phase 3, noninferiority trials, TANGO I and TANGO II. TANGO I compared meropenem-vaborbactam against piperacillin-tazobactam in patients with cUTIs and was found to be noninferior for overall success and microbial eradication. TANGO II expanded to other disease states (bacteremia, hospital-acquired/ventilator-associated bacterial pneumonia [HAP/VAP], complicated intra-abdominal infection [cIAI], cUTI/AP) and was found to be noninferior against best available therapy (BAT) with respect to clinical cure at the end of treatment and the test of cure. Meropenem-vaborbactam maintained the established safety profile of meropenem alone, with headache as the most common adverse event in both phase 3 studies. Overall, clinical efficacy has been demonstrated and suggests the use of meropenem-vaborbactam for the treatment of cUTI is an option.

Metallic Nanosystems in the Development of Antimicrobial Strategies with High Antimicrobial Activity and High Biocompatibility

Antimicrobial resistance is a major and growing global problem and new approaches to combat infections caused by antibiotic resistant bacterial strains are needed. In recent years, increasing attention has been paid to nanomedicine, which has great potential in the development of controlled systems for delivering drugs to specific sites and targeting specific cells, such as pathogenic microbes. There is continued interest in metallic nanoparticles and nanosystems based on metallic nanoparticles containing antimicrobial agents attached to their surface (core shell nanosystems), which offer unique properties, such as the ability to overcome microbial resistance, enhancing antimicrobial activity against both planktonic and biofilm embedded microorganisms, reducing cell toxicity and the possibility of reducing the dosage of antimicrobials. The current review presents the synergistic interactions within metallic nanoparticles by functionalizing their surface with appropriate agents, defining the core structure of metallic nanoparticles and their use in combination therapy to fight infections. Various approaches to modulate the biocompatibility of metallic nanoparticles to control their toxicity in future medical applications are also discussed, as well as their ability to induce resistance and their effects on the host microbiome.

Development and Evaluation of the Efficacy and Toxicity of a New Hybrid Antimicrobial Peptide MY8

BACKGROUND

Antibiotics have led to significant advancements in medicine. Unfortunately, they were faced with the emergence of pathogen resistance. According to the World Health Organization, antimicrobial resistance has been declared one of humanity's top ten global public health threats. The risk of those bacteria is not only from their being resistant to multi-antibiotics but also from their ability to form biofilms, which can be 1,000 times more resistant than planktonic bacteria.

METHOD

This study used rational design to hybridize two antimicrobial peptides, aiming to enhance their efficacy and stability with reduced toxicity.

RESULTS

The MY8 novel peptide was designed from the parent peptides BMAP-27 and CAMP 211-225. Some amino acid modifications were introduced to the hybrid peptide to improve its physicochemical properties guided by several software. Its antimicrobial activity has been studied against gram-negative and gram-positive strains, which showed broad-spectrum activity with MIC values against planktonic bacteria ranging from 0.125 to 25 μM. In contrast, 25-200 μM were needed to eradicate biofilms. Moreover, the MY8 peptide showed synergism with four conventional antibiotics., It also showed reduced toxicity against mammalian cells and a slight hemolysis tendency towards erythrocytes.

CONCLUSION

The design of the MY8 peptide was successful, resulting in a novel, potent, broad-spectrum antimicrobial peptide with reduced toxicity and possible synergism with conventional antibiotics.

Phenotypic and Genotypic Characterization of Carbapenem-Resistant Enterobacteriaceae Recovered from a Single Hospital in China, 2013 to 2017

Objective

Carbapenem-resistant Enterobacteriaceae (CRE) have become an increasingly common cause of healthcare-related infections and present a serious challenge to clinical treatment. This study examined the phenotypic, genotypic characterization, clinical, and microbiological data of CRE in the Huizhou Municipal Central Hospital.

Methods

We conducted a phenotypic susceptibility evaluation and whole genome sequence analysis for 52 CRE strains isolated from 37 patients and 2 medical device-related samples during 2013-2017 to characterize risk factors, antimicrobial resistance profiles, dominant clones and hospital transmission.

Results

Long-term hospitalization, treatment time with antibiotics and use of invasive devices were linked to the risk of CRE infection. The carbapenem resistance genes (CRGs) we found included bla_NDM (82.7%), bla_IMP (19.2%) and bla_KPC (3.8%), Escherichia coli (44.2%) and Klebsiella pneumoniae (44.2%) were the dominant species we identified, and the type of CRG carried by isolates was highly correlated with species. The coexistence of CRGs with a variety of other antibiotic resistance genes leads to an increased prevalence of high resistance levels for CRE to β-lactams and other antibiotic classes such as aminoglycosides and fluoroquinolones. These isolates were sensitive only to colistin and tigecycline. In addition to this, we observed significantly genomic diversity of CRE isolates in this hospital. Importantly, we found that long-term transmission of multiple CRE clones had occurred at this hospital between various wards.

Conclusion

Evaluating and improving the current infection control strategies may be necessary, and reducing nosocomial transmission remains the primary control element for CRE infections in China.

Massive sequencing of the V3-V4 hypervariable region of bronchoalveolar lavage from patients with COVID-19 and VAP reveals the collapse of the pulmonary microbiota

Background. The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic is a predisposing factor for the development of healthcare-associated infections, of which ventilator-associated pneumonia (VAP) is one.Hypothesis. VAP is caused by ESKAPE bacteria and other pathogens not detected by microbiological culture.Aim. To elucidate the bacterial pathogens of severe coronavirus disease 2019 (COVID-19) and VAP patients by massive sequencing and to predict their degree of relationship with the age and sex of the patients.Methods. Analysis of ribosomal libraries of the V3-V4 hypervariable region obtained by Illumina sequencing of bronchoalveolar lavages from COVID-19 and VAP (first wave) patients from Hospital Juárez de México.Results. Acinetobacter and Pseudomonas were the main bacterial genera in the bronchoalveolar lavages (BALs) analysed. Other members of the ESKAPE group, such as Enterococcus and Klebsiella, were also identified. Taxonomic composition per patient showed that non-ESKAPE genera were present with significant relative abundances, such as Prevotella, Stenotrophomas, Enterococcus, Mycoplasma, Serratia and Corynebacterium. Kruskal-Wallis analysis proved that VAP acquisition is an adverse event that is not influenced by the sex and age of COVID-19 patients.Discussion. Metagenomic findings in COVID-19/VAP patients highlight the importance of implementing comprehensive microbiological diagnostics by including alternative tools for the detection of the causal agents of healthcare-associated infections (HAIs).Conclusions. Timely identification of bacteria 'not sought' in diagnostic bacteriology laboratories will allow specific and targeted treatments. Implications for the restricted diagnosis of VAP causative agents in COVID-19 patients and the presence of pathogens not detected by classical microbiology are analysed and discussed.

MRSA in Humans, Pets and Livestock in Portugal: Where We Came from and Where We Are Going

Over the years, molecular typing of methicillin-resistant S. aureus (MRSA) has allowed for the identification of endemic MRSA strains and pathogenic strains. After reaching a peak of predominance in a given geographic region, MRSA strains are usually replaced by a new strain. This process is called clonal replacement and is observed worldwide. The worldwide spread of hospital-associated MRSA (HA-MRSA), community-associated MRSA (CA-MRSA) and livestock-associated MRSA (LA-MRSA) clones over the last few decades has allowed this microorganism to be currently considered a pandemic. In Portugal, most HA-MRSA infections are associated with EMRSA-15 (S22-IV), New York/Japan (ST5-II) and Iberian (ST247-I) clones. Regarding the strains found in the community, many of them are frequently associated with the hospital environment, namely the Pediatric, Brazilian and Iberian clones. On the other hand, a strain that is typically found in animals, MRSA clonal complex (CC) 398, has been described in humans as colonizing and causing infections. The ST398 clone is found across all animal species, particularly in farm animals where the economic impact of LA-MRSA infections can have disastrous consequences for industries. In contrast, the EMRSA-15 clone seems to be more related to companion animals. The objective of this review is to better understand the MRSA epidemiology because it is, undoubtedly, an important public health concern that requires more attention, in order to achieve an effective response in all sectors.

Meeting the Unmet Need in the Management of MDR Gram-Positive Infections with Oral Bactericidal Agent Levonadifloxacin

Levonadifloxacin (intravenous) and its oral prodrug alalevonadifloxacin are broad-spectrum antibacterial agents developed for the treatment of difficult-to-treat infections caused by multidrug-resistant Gram-positive bacteria, especially methicillin-resistant Staphylococcus aureus, atypical bacteria, anaerobic bacteria, and biodefence pathogens as well as Gram-negative bacteria. Levonadifloxacin has a well-defined mechanism of action involving a strong affinity for DNA gyrase as well as topoisomerase IV. Alalevonadifloxacin with widely differing solubility and oral bioavailability has pharmacokinetic profile identical to levonadifloxacin. Unlike existing MRSA drugs such as vancomycin and linezolid, which cause unfavorable side effects like nephrotoxicity, bone-marrow toxicity, and muscle toxicity, levonadifloxacin/alalevonadifloxacin has demonstrated superior safety and tolerability features with no serious adverse events. Levonadifloxacin/alalevonadifloxacin could be a useful weapon in the battle against infections caused by resistant microorganisms and could be a preferred antibiotic of choice for empirical therapy in the future.

Antimicrobial Susceptibility and Molecular Characterization of Escherichia coli Recovered from Milk and Related Samples

There is a rising concern about illnesses resulting from milk consumption due to contamination by pathogenic microorganisms including Escherichia coli. This study examined the occurrence and antimicrobial susceptibility of E. coli isolated from cow milk and related samples. Furthermore, partial sequencing was done to ascertain the genetic relatedness and possible cross contamination among the samples. In all, 250 samples, that is, 50 each of raw milk, cow teat, milkers’ hands, milking utensils, and fecal matter of cows, were cultured for the identification of E. coli. E. coli was detected in 101/250 samples (40.4%). Milk and fecal samples recorded the highest percentages of 68.0% and 66.0%, respectively. Forty-two (42) E. coli strains examined for antimicrobial resistance showed an overall 25.5% resistance, 15.0% intermediate resistance, and 59.5% susceptibility. The isolates had a high level of resistance to teicoplanin (100.0%), but were susceptible to chloramphenicol (95.2%) and azithromycin (92.9%). The Multiple Antibiotic Resistance (MAR) index pattern ranged from 0.1 to 0.5, and 40.5% exhibited multiple drug resistance. The E. coli strains formed 11 haplotypes, and a phylogenic tree analysis showed relatedness among the isolates in other African countries. This observation is an indication of cross contamination among the milk and its related samples.

Potent Activity of a High Concentration of Chemical Ozone against Antibiotic-Resistant Bacteria

BACKGROUND

Health care-associated infections (HAIs) are a significant public health problem worldwide, favoring multidrug-resistant (MDR) microorganisms. The SARS-CoV-2 infection was negatively associated with the increase in antimicrobial resistance, and the ESKAPE group had the most significant impact on HAIs. The study evaluated the bactericidal effect of a high concentration of O3 gas on some reference and ESKAPE bacteria.

MATERIAL AND METHODS

Four standard strains and four clinical or environmental MDR strains were exposed to elevated ozone doses at different concentrations and times. Bacterial inactivation (growth and cultivability) was investigated using colony counts and resazurin as metabolic indicators. Scanning electron microscopy (SEM) was performed.

RESULTS

The culture exposure to a high level of O3 inhibited the growth of all bacterial strains tested with a statistically significant reduction in colony count compared to the control group. The cell viability of S. aureus (MRSA) (99.6%) and P. aeruginosa (XDR) (29.2%) was reduced considerably, and SEM showed damage to bacteria after O3 treatment Conclusion: The impact of HAIs can be easily dampened by the widespread use of ozone in ICUs. This product usually degrades into molecular oxygen and has a low toxicity compared to other sanitization products. However, high doses of ozone were able to interfere with the growth of all strains studied, evidencing that ozone-based decontamination approaches may represent the future of hospital cleaning methods.

Multicenter surveillance of in vitro activities of cefepime-zidebactam, cefepime-enmetazobactam, omadacycline, eravacycline, and comparator antibiotics against Enterobacterales, Pseudomonas aeruginosa, and Acinetobacter baumannii complex causing bloodstream infection in Taiwan, 2020

OBJECTIVES

: To determine the in vitro activities of novel and comparator antibiotics against gram-negative bacteria (GNB) in Taiwan.

METHODS

: Isolates of Escherichia coli (n = 335), Klebsiella pneumoniae (n = 316; 144 isolates with hyperviscosity characteristics), Pseudomonas aeruginosa (n = 271), Acinetobacter baumannii complex species (n = 187), and non-typhoidal Salmonella species (n = 226), Shigella species (n = 13) from miscellaneous culture sources were collected in 2020 in Taiwan. The MICs of the isolates to test antibiotics were determined using the broth microdilution method. GeneXpert was used to detect genes encoding carbapenemases among the carbapenem-non-susceptible (NS) Enterobacterales isolates.

RESULTS

: The MIC values of the cefepime-enmetazobactam combination against extended-spectrum β-lactamase-producing E. coli and K. pneumoniae isolates (MIC₉₀ ≤ 0.5 mg/L), bla_KPC-harboring E. coli isolates (0.25 mg/L; n = 2), and 80% of bla_OXA-48-like gene-harboring K. pneumoniae isolates (≤2 mg/L) were low. The MIC ranges of the cefepime-zidebactam against carbapenemase-producing Enterobacterales isolates (irrespective of the carbapenemase type [MIC₉₀ ≤ 4 mg/L]) and carbapenem-NS or ceftolozane-tazobactam-NS P. aeruginosa isolates (MIC₉₀ value, 8 mg/L) were significantly lower than those of the cefepime-enmetazobactam.

CONCLUSIONS

: The efficacy of novel antibiotics against important drug-resistant GNB must be monitored and validated during the clinical treatment of patients.

Quorum sensing inhibition of hordenine analogs on Pseudomonas aeruginosa and Serratia marcescens

Quorum sensing (QS) plays an essential role in virulence factor production, biofilm formation, and antimicrobial resistance. As a potent QS inhibitor, hordenine can inhibit both QS and biofilm formation in Pseudomonas aeruginosa and Serratia marcescens. In this work, we tested the QS inhibitory potential of 27 hordenine analogs against QS and biofilm formation in P. aeruginosa and S. marcescens. Among the tested analogs, seven (12, 28, 27, 26, 2, 23, and 7) exhibited strong QS inhibitory activity against P. aeruginosa, five of which (12, 28, 27, 26, and 2) showed better inhibitory activity than hordenine. In addition, seven analogs (28, 12, 23, 7, 26, 2, and 27) exhibited better biofilm inhibition against P. aeruginosa than hordenine. Four analogs (7, 28, 2, and 12) showed QS inhibitory activity against S. marcescens, two of which (7 and 28) demonstrated better inhibitory activity than hordenine. Furthermore, analog 7 showed similar biofilm inhibition against S. marcescens as hordenine. Structure-activity relationship (SAR) analysis indicated that the inhibitory activities of the analogs were related to four factors, i.e., carbon chain length, presence or absence of an α,β-C Created by potrace 1.16, written by Peter Selinger 2001-2019 ]]>C bond, amino group with/without lipophilic group, such as methyl group, and hydroxyl group in benzene ring.

Novel mesoporous silica nanocarriers containing gold; a rapid diagnostic tool for tuberculosis

Tuberculosis (TB) is major health concern and reason of deaths from decades to current date. Even though with a lot of advancements, diagnostic techniques, and discovery of standard antibiotics TB remains crucial challenge and can create worst scenario for human health in near future. Nanoparticles play emerging role in diagnosis and treatment of TB. In this study, we developed mesoporous silica nanoparticles containing gold (MSNs@GNPs) for rapid diagnosis and treatment of TB. The physicochemical characterization revealed effective surface morphology and particles diameter, that is applicable for in vitro applications. The in vitro antimicrobial analysis revealed that the designed MSNs@GNPs has retained significantly lower minimal inhibitory concentration (MIC) values and can effectively demolish mycobacterium tuberculosis (Mtb). Furthermore, the diagnosis efficiency of the MSNs@GNPs was evaluated by calorimetric analysis. Which demonstrates that MSNs@GNPs can be used for rapid diagnosis of the tuberculosis when applied on in vitro culture of the Mtb. The current study needs further verification on human's clinical samples from tuberculosis patients. However, MSNs@GNPs can be a versatile clinical approach for the rapid diagnosis and clinical treatment of the tuberculosis.

Antibiotic Resistance Profile of Common Bacteria Isolated from Blood Stream, Lower Respiratory Tract and Urinary Infections in Intensive Care Unit in Saudi Arabia: A Retrospective Study

Background

The rate of infections in the intensive care units (ICUs) is rising, mainly because of the increasing use of invasive procedures and specialized devices. This study aimed to identify the antibiotic resistance profile of common bacteria isolated from lower respiratory tract infections (LRTIs), bloodstream infections (BSIs), and urinary infections (UTIs) in ICUs in Saudi Arabia.

Methods

In the current retrospective study, the isolates and antibiotic resistance were collected from the Electronic Medical Record (EMR) for respiratory, blood, and urine samples. The study sample compromised 96 patients admitted to the ICU at least for 48 hours and have a central venous catheter (CVC) between November 1, 2020, and January 31, 2021.

Results

66 (68.8%) of the study sample were males, and 30 (31.2%) were females. LRTIs were the most common isolates (51 samples), followed by BSIs (28 samples) and UTIs (17 samples). The isolated pathogens in this study were Klebsiella pneumoniae (K. pneumoniae) (59.4%), Coagulase-negative staphylococci (CoNS) (11.5%), Escherichia coli (E. coli) (8.4%), Acinetobacter baumannii (A. baumannii) (7.3%), and Staphylococcus aureus (S. aureus) (6.2%). BSI were frequently caused by CoNS (35.7%) and K. pneumoniae (35.7%), while Methicillin-resistant Staphylococcus aureus (MRSA) represented 10.7% of BSI. Vancomycin, Synercid, and Teicoplanin were the commonly used antibiotics and showed 100% sensitivity among S. aureus, including MRSA, while almost 100% resistance was observed for penicillin and oxacillin against the same organisms. The maximum resistance was observed with aztreonam (96.4%), ampicillin (87.3%), followed by co-amoxiclav (83.9%), cotrimoxazole (79.5%) and cephalosporin group antibiotics.

Conclusions

Strict adherence to infection prevention practices and wise use of antibiotics are recommended to slow the spread of antimicrobial resistance (AMR).

Antibiotic resistance in microbes: History, mechanisms, therapeutic strategies and future prospects

Antibiotics have been used to cure bacterial infections for more than 70 years, and these low-molecular-weight bioactive agents have also been used for a variety of other medicinal applications. In the battle against microbes, antibiotics have certainly been a blessing to human civilization by saving millions of lives. Globally, infections caused by multidrug-resistant (MDR) bacteria are on the rise. Antibiotics are being used to combat diversified bacterial infections. Synthetic biology techniques, in combination with molecular, functional genomic, and metagenomic studies of bacteria, plants, and even marine invertebrates are aimed at unlocking the world's natural products faster than previous methods of antibiotic discovery. There are currently only few viable remedies, potential preventive techniques, and a limited number of antibiotics, thereby necessitating the discovery of innovative medicinal approaches and antimicrobial therapies. MDR is also facilitated by biofilms, which makes infection control more complex. In this review, we have spotlighted comprehensively various aspects of antibiotics viz. overview of antibiotics era, mode of actions of antibiotics, development and mechanisms of antibiotic resistance in bacteria, and future strategies to fight the emerging antimicrobial resistant threat.

No Correlation between Biofilm Formation, Virulence Factors, and Antibiotic Resistance in Pseudomonas aeruginosa: Results from a Laboratory-Based In Vitro Study

Pseudomonas aeruginosa (P. aeruginosa) possesses a plethora of virulence determinants, including the production of biofilm, pigments, exotoxins, proteases, flagella, and secretion systems. The aim of our present study was to establish the relationship between biofilm-forming capacity, the expression of some important virulence factors, and the multidrug-resistant (MDR) phenotype in P. aeruginosa. A total of three hundred and two (n = 302) isolates were included in this study. Antimicrobial susceptibility testing and phenotypic detection of resistance determinants were carried out; based on these results, isolates were grouped into distinct resistotypes and multiple antibiotic resistance (MAR) indices were calculated. The capacity of isolates to produce biofilm was assessed using a crystal violet microtiter-plate based method. Motility (swimming, swarming, and twitching) and pigment-production (pyoverdine and pyocyanin) were also measured. Pearson correlation coefficients (r) were calculated to determine for antimicrobial resistance, biofilm-formation, and expression of other virulence factors. Resistance rates were the highest for ceftazidime (56.95%; n = 172), levofloxacin (54.97%; n = 166), and ciprofloxacin (54.64%; n = 159), while lowest for colistin (1.66%; n = 5); 44.04% (n = 133) of isolates were classified as MDR. 19.87% (n = 60), 20.86% (n = 63) and 59.27% (n = 179) were classified as weak, moderate, and strong biofilm producers, respectively. With the exception of pyocyanin production (0.371 ± 0.193 vs. non-MDR: 0.319 ± 0.191; p = 0.018), MDR and non-MDR isolates did not show significant differences in expression of virulence factors. Additionally, no relevant correlations were seen between the rate of biofilm formation, pigment production, or motility. Data on interplay between the presence and mechanisms of drug resistance with those of biofilm formation and virulence is crucial to address chronic bacterial infections and to provide strategies for their management.

Genetic characterization of Carbapenem-Resistant Escherichia coli from China, 2015-2017

BACKGROUND

The molecular characteristics of carbapenem-resistant Escherichia coli (CREco) remain unclear.

METHODS

We conducted a multi-center bacterial resistance monitoring project from 2015 to 2017.The minimum inhibitory concentrations ofCREco were determined bybroth microdilution method. The genome sequencing of CREcoisolates was performed, and single-nucleotide polymorphism (SNP) was analyzed.

RESULTS

A total of 144CREcoisolatescollected from 10 cities in China were involved in this study. ST167 (n = 43) is the most popular type, followed by ST410(n = 14), ST131(n = 9). There were 102 (70.83%) CREco isolates that produced various NDMs, including NDM-1 (n = 16), NDM-4(n = 1), NDM-5(n = 79), NDM-6(n = 2) and NDM-9(n = 4). In addition, 15 isolates produced KPC-2, three isolates wereIMP-4 positive, and three isolates produced OXA-48. Genetic relatedness and phylogenetic analysis showed that isolates with the same ST had a high degree of homology. Some STs (including ST167, ST410, ST131, ST46, ST405 and ST617) exhibited a trend of outbreak.

CONCLUSIONS

The majority of CREco belonged to ST167, followed by ST410 and ST131, and most of them carried various NDM-coding genes. The spread of high-risk clones of CREco has occurred in different regions of China.

Clonal Dissemination of Multiple Carbapenemase Genes in Carbapenem-Resistant Enterobacterales Mediated by Multiple Plasmids in China

Background

Carbapenem-resistant Enterobacterales (CRE) are rapidly increasing worldwide in last two decades and lead few antibiotics for treatment. The molecular epidemiology of CRE in China was investigated to provide basis for clinical rational use of antibiotics and prevent its spread.

Methods

All CRE isolates in this study were collected from 11 hospitals from October 2015 to July 2018. The isolates were subjected to antimicrobial susceptibility tests, PCR molecular identification, pulsed-field gel electrophoresis, and multilocus sequence typing.

Results

Among the 399 CRE isolates, 51.6% (206/399) harbored carbapenemase genes. Three carbapenemase genes were detected, namely bla _KPC-2, bla _NDM-1, and bla _IMP at rates of 29.8% (119/399), 17.5% (70/399), and 4.0% (16/399), respectively. In Klebsiella pneumoniae (350) and Escherichia coli (26), bla _KPC-2 (33.4%, 117/350) and bla _NDM-1 (61.5%, 16/26) were the predominant genes. The most common genes in the CRE isolates were bla _KPC (85.5%) and bla _NDM-1 (76.5%) from adults and children, respectively. Particularly, ST11 K. pneumoniae with bla _KPC-2 harbored by IncFII plasmids were distributed in both general and primary hospitals, suggesting a clonal transmission pattern at these sites. In addition, the clonal distribution of ST2407 K. pneumoniae with bla _NDM-1 located on IncX3 plasmids and bla _IMP-38-positive ST307 K. pneumoniae were detected in a children's hospital.

Conclusion

The distribution of carbapenemase genes differed among strains and age groups. Multiple carbapenemase genes in the CRE strains were clonally disseminated in the tested regions mediated by multiple plasmids. Therefore, CRE monitoring should be increased and measures should be adopted to prevent its transmission.

Knowledge and Awareness of Physicians About Rational Antibiotic Use and Antimicrobial Resistance Before and After Graduation: A Cross-Sectional Study Conducted in Malatya Province in Turkey

BACKGROUND

We aimed to evaluate the level of theoretical knowledge of rational antibiotic use and awareness about emergence of multidrug resistance (MDR) among the senior students at a medical school and the actively-working family physicians.

METHODS

This cross-sectional research was carried out between 1 February and 30 April 2019 in Malatya province. Two-hundred twenty-five senior students in the Inonu University Medical School (Group 1) and 230 actively-working family physicians in Malatya primary health care services who were found to be eligible (Group 2) were included in this study. Power analysiscalculated the minimum of 240 participants with a proportion difference of 0.18 between the groups, a type I error of 0.05 and a type II error of 0.20. A questionnaire including seven sections and 28 questions was applied to the participants.

RESULTS

Doctors were more hesitant in pre-graduation and more self-confident in the post-graduation period for the decision to start antibiotic treatment. In addition, doctors forget their theoretical knowledge of antibiotics over time and are unable to follow current developments after graduation. The most important concern in the pre-graduation period was the choice of antibiotics from the wrong group, while in the post-graduation period it is the fear of the presence of unproven infection.

CONCLUSION

Physicians' antibiotic prescribing habits, attitudes and behaviors vary before and after graduation. Sustainable education for antibiotic use for physicians after graduation can contribute positively to reduce of antimicrobial resistance rates and to increase awareness about the use of rational antibiotics.

First insights into molecular basis identification of 16 s ribosomal RNA gene of Staphylococcus aureus isolated from Sudan

Objective

In this study, we analyzed the molecular evolution of Staphylococcus aureus isolates using 16S rRNA gene and phylogenetic analysis to detect the prevalence of S. aureus infections in Sudan.

Results

Molecular detection of S. aureus has shown that 20 (43.47%) of patients were positive for S. aureus. The phylogenetic tree of 16S rRNA sequences was divided into three lineages of S. aureus isolates detected from wound infections in Sudan. Nucleotides base-pair substitution was appeared at position 249. This mutation do not linked with Macrolides, Lincosamides and Streptogramines b resistant phenotype. Further studies should investigate the effect of that mutation on resistance to other antibiotics.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13104-021-05569-w.

Prevalence of Antibiotic Resistance of ESKAPE Pathogens Over Five Years in an Infectious Diseases Hospital from South-East of Romania

PURPOSE

This study aimed at identifying the main antimicrobial resistance of ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Escherichia coli) pathogens in a Romanian infectious diseases hospital. This antimicrobial resistance is a global threat, having high rates of multidrug resistance and limited treatment options.

PATIENTS AND METHODS

This retrospective study (2016-2020) assessed the antimicrobial resistance of ESKAPE pathogens isolated from the patient's biological samples. The microbiological diagnosis was performed by classical culture methods. The antimicrobial susceptibility analysis used the Kirby-Bauer disk-diffusion method and the method of minimum inhibiting concentration with the automated Vitek, according to the CLSI (Clinical and Laboratory Standards Institute) standards.

RESULTS

Included in this study were 4293 bacterial isolates: 67% Gram-negative bacilli, 31% Gram-positive cocci and 2% other morphotinctorial bacteria. ESKAPE pathogens were found in 97% of the bacterial isolates strains; E. coli (38.26%) and Staphylococcus aureus (26%) were the most prevalent. Most bacterial strains were isolated from urine cultures (45.6%), skin and soft tissue secretions/collections (35.9%) and also blood cultures (4.2%). Increased antimicrobial resistance was observed for methicillin-resistant Staphylococcus aureus (MRSA)s, extended spectrum beta-lactamase producing (ESBL) Enterobacterales, carbapenem-resistant (CR) Pseudomonas aeruginosa, Acinetobacter baumannii and Klebsiella pneumoniae. No vancomycin resistance was found for Enterococcus faecium. The highest prevalence rates of multidrug resistance were found in methicillin-resistant Staphylococcus aureus (86.6%), Acinetobacter baumannii (36.8%), Pseudomonas aeruginosa (29.1%) and Klebsiella pneumoniae (24.4%).

CONCLUSION

ESKAPE pathogens are frequently isolated in the infectious diseases hospital, with main antimicrobial resistance: ESBL, MRSA and CR. The local antimicrobial resistance pattern is essential in updating the local protocols and for appropriately prescribing antibiotics. Streamlining microbiological diagnosis and aligning with the European standards for antimicrobial susceptibility testing are necessary steps in harmonizing the regional network for good antimicrobial resistance control practices.

Pediatricians' Compliance to the Clinical Management Guidelines for Community-Acquired Pneumonia in Infants and Young Children in Pakistan

Community-acquired pneumonia (CAP) is among the most commonly prevailing acute infections in children that may require hospitalization. Inconsistencies among suggested care and actual management practices are usually observed, which raises the need to assess local clinical practices. The current study was conducted to evaluate pediatricians’ compliance with the standard clinical practice guidelines and their antibiotic-prescribing behavior for the management of CAP in children. Methods: A descriptive cross-sectional study was conducted using a self-administered questionnaire; which was provided to pediatricians by the researchers. Statistical analysis was performed with SPSS 25 Statistics; χ² tests (or Fisher-exact tests) with the p-value set at < 0.05 as the threshold for statistical significance. Results: The overall response rate was 59.2%. Male respondents were (n = 101; 42.6%), and the respondents (n = 163; 68.7%) were under 30 years of age. Amoxicillin (n = 122; 51.5%) was considered as the most commonly used first-line treatment for non-severe pneumonia, whereas a smaller proportion (n = 81; 34.2%) of respondents selected amoxicillin–clavulanate. Likewise, amoxicillin (n = 100; 42.2%) was the most popular choice for non-severe pneumonia in hospitalized children; however, if children had used antibiotics earlier to admission, respondents showed an inclination to prescribe a macrolide (n = 95; 40.0%) or second-generation cephalosporin (n = 90; 37.9%). More than 90% responded that children <6 months old with suspected bacterial CAP will probably receive better therapeutic care by hospitalization. Restricting exposure to the antibiotic as much as possible (n = 71; 29.9%), improving antibiotic prescribing (n = 59; 24.8%), and using the appropriate dose of antimicrobials (n = 29; 12.2%) were considered the major factors by the respondents to reduce antimicrobials resistance. Conclusions: The selection of antibiotics and diagnostic approach was as per the recommendations, but indication, duration of treatment, and hospitalization still can be further improved.

Use of antimicrobials and antimicrobial resistance in Nepal: a nationwide survey

Nepal suffers from high burden of antimicrobial resistance (AMR) due to inappropriate use of antibiotics. The main objective of this study was to explore knowledge, attitude and practices of antibiotics uses among patients, healthcare workers, laboratories, drug sellers and farmers in eight districts of Nepal. A cross-sectional survey was conducted between April and July 2017. A total of 516 individuals participated in a face-to-face interview that included clinicians, private drug dispensers, patients, laboratories, public health centers/hospitals and, livestock and poultry farmers. Out of 516 respondents, 62.8% (324/516) were patients, 16.9% (87/516) were clinicians, 6.4% (33/516) were private drug dispensers. A significant proportion of patients (42.9%; 139/324) thought that fever could be treated with antibiotics. Majority (79%; 256/324) of the patients purchased antibiotics over the counter. The knowledge of antibiotics used among patients increased proportionately with the level of education: literate only [AOR = 1.4 (95% Cl = 0.6-4.4)], versus secondary education (8-10 grade) [AOR = 1.8 (95% Cl = 1.0-3.4)]. Adult patients were more aware of antibiotic resistance. Use of antibiotics over the counter was found high in this study. Knowledge, attitude and practice related to antibiotic among respondents showed significant gaps and need an urgent effort to mitigate such practice.

Trends in antibiotic resistance for over 700,000 Escherichia coli positive urinary tract infections over six years (2014-2019) from a university teaching hospital

Introduction

Antibiotic microbial resistance (AMR) is a global health problem. Our aim was to review the resistance of Escherichia (E.coli) to antibiotics at our university hospital over a six-year period and see whether our protocol based antibiotic policy over this time led to any change in the resistance patterns.

Material and methods

Sensitivities of E.coli urine isolates between 2014–2019 (6-years) were sourced from the hospital and general practitioners in the community and collected from the microbiology department. Trends of resistance for amoxicillin, tazocin, cefalexin, ciprofloxacin, co-amoxiclav, gentamicin, nitrofurantoin, trimethoprim, amikacin, and pivmecillinam were examined using the Cochran-Armitage test.

Results

712,004 urine samples tested positive for E. coli. The overall resistance trends for cefalexin, nitrofurantoin and amikacin remained equivocal; increased for ciprofloxacin, co-amoxiclav, gentamicin, and tazocin; and decreased for fosfomycin, pivmecillinam, and trimethoprim.

Conclusions

Despite our protocol based antibiotic policy, although the overall antibiotic resistance remained stable, there was an increasing trend in antibiotic resistance for more commonly used antibiotics including ciprofloxacin, co-amoxiclav, gentamicin, and tazocin reflecting their overall use for prophylaxis and treatment. We plan to continue our policy of reviewing our antibiotic usage and the prescribing protocol with the microbiology department to minimize antibiotic resistance.

Optimal empiric treatment for KPC-2-producing Klebsiella pneumoniae infections in critically ill patients with normal or decreased renal function using Monte Carlo simulation

BACKGROUND

Limited clinical studies describe the pharmacodynamics of fosfomycin (FOS), tigecycline (TGC) and colistin methanesulfonate (CMS) in combination against KPC-producing Klebsiella pneumoniae (KPC-Kp). Population pharmacokinetic models were used in our study. Monte Carlo simulation was conducted to calculate probability of target attainment (PTA) and cumulative fraction of response (CFR) of each agent alone and in combination against KPC-Kp in patients with normal or decreased renal function.

RESULTS

The simulated regimen of FOS 6 g q8h reached ≥90% PTA against a MIC of 64 mg/L in patients with normal renal function. For patients with renal impairment, FOS 4 g q8h could provide sufficient antimicrobial coverage against a MIC of 128 mg/L. And increasing the daily dose could result to the cut-off value to 256 mg/L in decreased renal function. For TGC, conventional dosing regimens failed to reach 90% PTA against a MIC of 2 mg/L. Higher loading and daily doses (TGC 200/400 mg loading doses followed by 100 mg q12h/200 mg q24h) were needed. For CMS, none achieved 90% PTA against a MIC of 2 mg/L in normal renal function. Against KPC-Kp, the regimens of 200/400 mg loading dose followed by 100 q12h /200 mg q24h achieved > 80% CFRs regardless of renal function, followed by CMS 9 million IU loading dose followed by 4.5/3 million IU q12h in combination with FOS 8 g q8h (CFR 75-91%).

CONCLUSIONS

The use of a loading dose and high daily dose of TGC and CMS in combination with FOS can provide sufficient antimicrobial coverage against critically ill patients infected with KPC-Kp.

Evidence of Antibiotic Resistance from Population-Based Studies: A Narrative Review

The 20th century witnessed the dawn of the antibiotic revolution and is now facing the rising phenomenon of antibiotic resistance. In this narrative review, we aim to describe antibiotic resistance in clinical practice settings through population-based studies from different countries reporting the role of misuse of antibiotics in the development of resistance and the clinical and economic burden associated. The misuse of antibiotics was documented in the wide population as well as in hospitals and care facilities. It was mainly reported as over-use and inappropriate prescribing. Improper dosage regimens and longer treatment duration were regarded as pivotal factors related to antibiotic resistance; the emerging strategy of "antibiotic-de-escalation" could be the key to overcome these issues. The investigation of the self-medication attitude revealed widespread antibiotic use without following medical instructions or medical consultation. Moreover, several studies established the association of antibiotic resistance with increased risk of longer hospitalizations and mortality, highlighting the heavy clinical and economic burden of this phenomenon. In this narrative review, the widespread inappropriate use of antibiotics emerged as one of the main causes of antibiotic resistance, which negative outcomes call for the development of antibiotic stewardship programs and global surveillance networks.

N-chlorotaurine, a potent weapon against multiresistant bacteria

Aims

N‐chlorotaurine (NCT) is a body‐own mild oxidizing antiseptic that can be applied topically as a well‐tolerated anti‐infective at many body sites. The objective of this study was to demonstrate its activity against representative nosocomial multidrug‐resistant bacteria.

Methods and Results

The bactericidal activity of NCT was tested in quantitative killing assays against a panel of multiresistant Gram‐positive and Gram‐negative clinical isolates. N‐chlorotaurine (1%, 55 mmol l⁻¹) reduced the number of CFU of strains of methicillin‐resistant Staphylococcus aureus, linezolid‐resistant Staphylococcus epidermidis, vancomycin‐resistant, and linezolid‐ and vancomycin‐resistant Enterococcus faecium, 3MRGN and 4MRGN Escherichia coli, Pseudomonas aeruginosa, Acinetobacter baumannii and Klebsiella pneumoniae by at least 2 log₁₀ steps after 15 min and completely or nearly to the detection limit after 30 min at pH 7·1 and 37°C.

Conclusion

The activity of NCT against these clinical isolates is similar to that against non‐resistant ATCC strains and therefore not influenced by antibiotic resistance. This can be explained by the oxidizing and chlorinating mechanism of action of NCT, which leads to an attack of multiple targets in the microorganisms.

Significance and Impact of the Study

The bactericidal spectrum of NCT is not restricted by resistance against antibiotics. Therefore, it can be used against resistant strains, too.

Bloodstream Infections Caused by Carbapenem-Resistant Enterobacterales: Risk Factors for Mortality, Antimicrobial Therapy and Treatment Outcomes from a Prospective Multicenter Study

Purpose

Carbapenem-resistant Enterobacterales bloodstream infections (CRE BSIs) have a high mortality. However, an optimal antimicrobial treatment has not been determined. This study was conducted to evaluate the risk factors for mortality and provided potential therapeutic options for treatment of CRE infection.

Patients and Methods

We investigated patients with CRE BSIs from 18 hospitals across nine Chinese provinces from January to December 2019. Data were collected from the medical records according to a pre-established questionnaire. Antimicrobial susceptibility testing and DNA sequencing were performed to investigate the characteristics of isolates.

Results

A total of 208 patients enrolled; the overall 30-day mortality rate was 46.2%. The causative pathogen was carbapenem-resistant Klebsiella pneumoniae (CRKP) (85.6%). Patients infected by ST11-KL64 CRKP had a high sepsis/septic shock incidence rate (p < 0.05). Sepsis/septic shock, short duration of antimicrobial therapy and empirical using tigecycline were independent risk factors for mortality (p < 0.05 for each risks). Appropriate therapy had better survival benefit than inappropriate therapy (p = 0.003). No difference was identified between monotherapy and combination therapy (p = 0.105). Tigecycline as a frequently used antimicrobial had poor therapeutic effect on BSI patients (p < 0.001). Carbapenem-based treatment had a better therapeutic effect on patients infected by isolates with meropenem MIC ≤ 8 mg/L (p = 0.022). The patients who received short duration of antimicrobial therapy had poorer prognosis (p < 0.001) than the patients who received long duration of antimicrobial therapy.

Conclusion

Reducing the mortality of CRE BSIs need to comprehensively consider whether the antimicrobials were used appropriately, together with infection severity and CRE strains.

Epidemiology of Community Origin Escherichia coli and Klebsiella pneumoniae Uropathogenic Strains Resistant to Antibiotics in Franceville, Gabon

Introduction

Urinary tract infection is one of the major causes of consultation, microbiologic exploration, intensive use of antibiotics worldwide, and the second leading cause of clinical consultation in community practice. Many bacteria play a role in the urinary tract infections etiology, including Enterobacteriaceae such as Escherichia coli (E. coli) and Klebsiella spp.

Objective

The study’s main objective was to examine the epidemiology of E. coli and Klebsiella pneumoniae (K. pneumoniae) uropathogenic strains resistant to antibiotics in Franceville.

Methodology

The study was carried out between January 2018 and June 2019 in Franceville South-East Gabon. We examined a total of 1086 cytobacteriological urine samples. The identification of E. coli and K. pneumoniae strains was carried out using the Vitek-2 compact automated system and the antibiogram with the disk diffusion method according to the European Committee on Antimicrobial Susceptibility Testing recommendations.

Results

The prevalence of urinary tract infections was 29.2% (317/1086), of which 25.1% and 4.1% were mono-infections and co-infections, respectively. The prevalence of UTIs with E. coli was 28.7% (91/317) with a predominance of isolation in women. K. pneumoniae was responsible for 16.2% (61/317) of UTIs. E. coli and K. pneumoniae Uropathogenic strains showed resistance to beta-lactams, quinolones and cotrimoxazole, whereas Nitrofurantoin, Amikacin, Imipenem and Ertapenem were the most active antibiotics against E. coli and K. pneumoniae uropathogenic strains.

Conclusion

This study showed a high prevalence of urinary tract infections with a major implication of E.coli and K. pneumoniae strains. E. coli and K. pneumoniae presented high frequency of resistance to antibiotics, highlighting the need to adapt their use accordingly at the local level.

Detection of TEM and CTX-M Genes in Escherichia coli Isolated from Clinical Specimens at Tertiary Care Heart Hospital, Kathmandu, Nepal

Background: Antimicrobial resistance (AMR) among Gram-negative pathogens, predominantly ESBL-producing clinical isolates, are increasing worldwide. The main aim of this study was to determine the prevalence of ESBL-producing clinical isolates, their antibiogram, and the frequency of ESBL genes (bla_TEM and bla_CTX-M) in the clinical samples from patients. Methods: A total of 1065 clinical specimens from patients suspected of heart infections were collected between February and August 2019. Bacterial isolates were identified on colony morphology and biochemical properties. Thus, obtained clinical isolates were screened for antimicrobial susceptibility testing (AST) using modified Kirby–Bauer disk diffusion method, while ESBL producers were identified by using a combination disk diffusion method. ESBL positive isolates were further assessed using conventional polymerase chain reaction (PCR) to detect the ESBL genes bla_TEM and bla_CTX-M. Results: Out of 1065 clinical specimens, 17.8% (190/1065) showed bacterial growth. Among 190 bacterial isolates, 57.4% (109/190) were Gram-negative bacteria. Among 109 Gram-negative bacteria, 40.3% (44/109) were E. coli, and 30.2% (33/109) were K. pneumoniae. In AST, 57.7% (n = 63) Gram-negative bacterial isolates were resistant to ampicillin and 47.7% (n = 52) were resistant to nalidixic acid. Over half of the isolates (51.3%; 56/109) were multidrug resistant (MDR). Of 44 E. coli, 27.3% (12/44) were ESBL producers. Among ESBL producer E. coli isolates, 58.4% (7/12) tested positive for the bla_CTX-M gene and 41.6% (5/12) tested positive for the bla_TEM gene. Conclusion: Half of the Gram-negative bacteria in our study were MDR. Routine identification of an infectious agent followed by AST is critical to optimize the treatment and prevent antimicrobial resistance.

Antimicrobial Resistance in Escherichia coli Strains Isolated from Humans and Pet Animals

Throughout scientific literature, we can find evidence that antimicrobial resistance has become a big problem in the recent years on a global scale. Public healthcare systems all over the world are faced with a great challenge in this respect. Obviously, there are many bacteria that can cause infections in humans and animals alike, but somehow it seems that the greatest threat nowadays comes from the Enterobacteriaceae members, especially Escherichia coli. Namely, we are witnesses to the fact that the systems that these bacteria developed to fight off antibiotics are the strongest and most diverse in Enterobacteriaceae. Our great advantage is in understanding the systems that bacteria developed to fight off antibiotics, so these can help us understand the connection between these microorganisms and the occurrence of antibiotic-resistance both in humans and their pets. Furthermore, unfavorable conditions related to the ease of E. coli transmission via the fecal-oral route among humans, environmental sources, and animals only add to the problem. For all the above stated reasons, it is evident that the epidemiology of E. coli strains and resistance mechanisms they have developed over time are extremely significant topics and all scientific findings in this area will be of vital importance in the fight against infections caused by these bacteria.