Erythromycin Research Articles

Fabrication and characterization of boric acid-crosslinked ethyl cellulose and polyvinyl alcohol films as potential drug release systems for topical drug delivery.

In this study, boric acid (BA) is employed as a crosslinking agent to improve the characteristics of two commonly used polymeric films, ethyl cellulose (EC) and polyvinyl alcohol (PVA), for topical drug delivery applications. The developed films are characterized by FTIR spectroscopy and SEM analysis. The results show that the surfaces of the prepared films are even and transparent, except for the BA-modified EC sample. The initial cumulative release for erythromycin (EM) is found to be 0.30 and 0.36 mg/mL for EC and PVA films, which drops to 0.25 and 0.20 mg/mL after BA crosslinking, respectively, after 1 h at 25 °C. Further, the developed formulations are stable for 75 days. Also, the antibacterial activity of the developed formulations is investigated against S. aureus (ATCC® 25923™ and ATCC® 29213™). The obtained data confirm that the application of BA as the crosslinking agent extends the release of EM from EC and PVA polymeric films. The findings of this study suggest that BA-crosslinked EC and PVA films are promising carriers for controlled topical drug delivery applications.

Comparison of antimicrobial resistance in thermophilic Campylobacter strains isolated from conventional production and backyard poultry flocks

ABSTRACT 1. The aim of this study was to compare the resistance pattern of thermophilic Campylobacter spp. isolated from conventional production (n = 34) and backyard poultry flocks (n = 36) from Rio de Janeiro State, Brazil. The disc diffusion method and statistical tests were used for investigation and analysis of the resistance pattern of Campylobacter spp. isolated from different rearing systems. 2. Antimicrobial resistance percentages to amoxycillin with clavulanic acid (AMC), ampicillin (AMP), ceftiofur (CTF), ciprofloxacin (CIP), enrofloxacin (ENO), erythromycin (ERI), gentamicin (GEN) and tetracycline (TET) were 32.4%, 44.1%, 67.6%, 97.1%, 82.4%, 26.5%, 5.9% and 38.2% in conventional production flocks respectively, while the backyard flock’s resistance levels were 0.0%, 13.9%, 69.4%, 100.0%, 91.7%, 5.6%, 0.0% and 16.7%, respectively. 3. Campylobacter spp. from conventional poultry production was more resistant to AMC, AMO, ERI and TET (P > 0.05) when compared to strains from backyard poultry. A higher frequency of resistance to fluoroquinolones (FLQ), CIP and ENO, was observed in strains from both systems, demonstrating the spread of resistant strains among poultry production environments.

Hand Microbiome And Resistant Strains From Cell Phones Of Health Personnel

Purpose:To investigate the hand microbiome of Health Personnel and the flora transferred to their hands from cell phones. Methods:The study was conducted in a tertiary care hospital over 3 months in 50 health personnel. Their dominant hand was placed on agar plates to establish the hand microbiome. After sanitizing and drying their hands, and using their phones for a few minutes, another handprint was taken to identify the bacteria on the phone. The bacteria were identified by standard microbiologic techniques. Results:Organisms identified in the normal microbiome included coagulase negative Staphylococci (CoNS, 90%), Klebsiella pneumoniae (16%), E. coli (8%), Staphylococcus aureus (4%), Pseudomonas aeruginosa (2%) and Acinetobacter spp. (2%). CoNS isolated were found to be resistant to co-amoxiclav (41.67%), cotrimoxazole (20.83%), erythromycin (20.83%) and clindamycin (20.83%). Maximum resistance was observed towards co-amoxiclav. The repeat handprint showed the colony count as decreased by four times. Bacteria found were CoNS (92%), E. coli (4%), Enterococcus (4%), Klebsiella (2%) and Acinetobacter (2%). Antibiotic sensitivity was similar here with additional resistance to cefepime and cefoxitin by CoNS. Conclusion:Hand microbiome of health personnel comprises bacteria that are dangerous to immunocompromised individuals and our phones are effectively transmitting multidrug resistant bacteria to our hands within a few moments of contact. There was also a notable lack of S. aureus in our samples, while many other studies have shown it to be a common nosocomial pathogen, found on hands of health personnel. Keywords:Hand microbiome, Health Personnel, Antibiotic resistance, cell phone

Assessment of door handles as potential reservoirs of drug-resistant enterococci

BackgroundFomites have long been known to play a key role in the spread of disease causing agents. Hospital-associated fomites in particular have been linked with transmission of members of the Enterococci sp which are key human pathogens. Few studies have explored the role non-hospital door handles might play as potential sources of these isolates. This study therefore set out to explore this role.ResultsA total of hundred toilet and office door handles in a tertiary institution in Rivers State, Nigeria, were sampled using the swab and rinse method. The presence and drug susceptibility of Enterococcus was determined using the selective bile esculin agar (BEA) and standard microbiological methods. Growth on BEA was observed in 71% of cases, with more growth (38/50, 76%) observed from toilet door handles. Only 35% of samples produced the characteristic black pigmentation associated with Enterococcus sp. Six different bacterial groups were identified from this subset with Enterococcus sp. making up only 14% (5/35) of the isolates. All (100%) Enterococci were isolated from toilet door handles. Antibiotic susceptibility testing revealed very high levels of resistance (80–100%) against 75% of the test antibiotics. An analysis of the antibiotic resistance pattern of each isolate revealed 11 unique antibiogram patterns. Only 2 of these patterns were associated with the enterococci, with majority (4/5) exhibiting resistance to Augmentin (AUG), Ceftazidime (CAZ), Ceftriaxone (CTR), Cefuroxime (CRX), Cloxacillin (CXC), Erythromycin (ERY), Gentamicin (GEN), Ofloxacin (OFL) (antibiogram of AUG–CAZ–CRX–CTR–CXC–ERY). None of the enterococci, however, was resistant to vancomycin.ConclusionThis study reports low level contamination of door handles by enterococci. Identical antibiogram patterns linked with majority of the enterococci could however point at the occurrence of a single clone perhaps indicating single source contamination. Reports of high levels of ampicillin resistance among these isolates are problematic as ampicillin–gentamicin combination is the treatment of choice for nosocomial enterococci pathogens.

Isolation, Molecular Detection and Antibiogram of Multi-drug Resistant Salmonella Typhimurium DT104 from Selected Dairy Farms in Mymensingh, Bangladesh

The Salmonella typhimurium DT104, an emerging cause of human illness has received an increasing attention due to its multidrug resistant properties. Since it has been isolated from human and other sources including food-producing animals around the world; it has become a worldwide public health concern. Therefore, the present study was designed to isolate, identify and study the antibiogram profile of multidrug resistant S. typhimurium DT104 from several dairy farms in Mymensingh district, Bangladesh. A total of 135 fecal samples from diarrhoeic cattle were collected aseptically and subjected for bacterial isolation, molecular detection using PCR followed by antibiogram study. Salmonella spp. could be isolated from a total of 39 (28.88%) samples based on cultural and staining methods which were further confirmed by PCR using invA gene specific primers. However, out of 39 Salmonella spp., 6 isolates were confirmed as S. typhimurium DT104 strain. Results of the antibiotic resistance patterns demonstrated that 100% (39/39) isolates were resistant to erythromycin followed by tetracycline (73.68%), colistin (89.47%), ampicillin (47.36%), gentamicin (21.05%), ciprofloxacin (31.57%), streptomycin (42.10%), enrofloxacin (10.52%) and chlormphenicol (31.57%). Moreover, about 23.07% isolates were resistant to more than 5 antibiotics. However, all the isolates were found to be sensitive to amikacin. These results suggest that antibiotic resistant S. typhimurium DT104 strain has been circulating in dairy cattle in Bangladesh which is alarming and may impose threat to livestock and public health due to lack of proper hygienic management. This study will be helpful for the selection of proper antibiotics against salmonellosis in cattle.

Application of Erythromycin and/or Raoultella sp. Strain MC3 Alters the Metabolic Activity of Soil Microbial Communities as Revealed by the Community Level Physiological Profiling Approach.

Erythromycin (EM), a macrolide antibiotic, by influencing the biodiversity of microorganisms, might change the catabolic activity of the entire soil microbial community. Hence, the goal of this study was to determine the metabolic biodiversity in soil treated with EM (1 and 10 mg/kg soil) using the community-level physiological profiling (CLPP) method during a 90-day experiment. In addition, the effect of soil inoculation with antibiotic-resistant Raoultella sp. strain MC3 on CLPP was evaluated. The resistance and resilience concept as well as multifactorial analysis of data was exploited to interpret the outcomes obtained. EM negatively affected the metabolic microbial activity, as indicated by the values of the CLPP indices, i.e., microbial activity expressed as the average well-color development (AWCD), substrate richness (R), the Shannon–Wiener (H) and evenness (E) indices and the AWCD values for the six groups of carbon substrate present in EcoPlates until 15 days. The introduction of strain MC3 into soil increased the degradative activity of soil microorganisms in comparison with non-inoculated control. In contrast, at the consecutive sampling days, an increase in the values of the CLPP parameters was observed, especially for EM-10 + MC3-treated soil. Considering the average values of the resistance index for all of the measurement days, the resistance of the CLPP indices and the AWCD values for carbon substrate groups were categorized as follows: E > H > R > AWCD and polymers > amino acids > carbohydrates > miscellaneous > amines > carboxylic acids. The obtained results suggest a low level of resistance of soil microorganisms to EM and/or strain MC3 at the beginning of the exposure time, but the microbial community exhibited the ability to recover its initial decrease in catabolic activity over the experimental period. Despite the short-term effects, the balance of the soil ecosystem may be disturbed.

Adsorption of pharmaceuticals from aqueous solutions using biochar derived from cotton gin waste and guayule bagasse

Biochars produced from cotton gin waste (CG) and guayule bagasse (GB) were characterized and explored as potential adsorbents for the removal of pharmaceuticals (sulfapyridine-SPY, docusate-DCT and erythromycin-ETM) from aqueous solution. An increase in biochar pyrolysis temperature from 350 οC to 700 οC led to an increase in pH, specific surface area, and surface hydrophobicity. The electronegative surface of all tested biochars indicated that non-Coulombic mechanisms were involved in adsorption of the anionic or uncharged pharmaceuticals under experimental conditions. The adsorption capacities of Sulfapyridine (SPY), Docusate (DCT) and Erythromycin (ETM) on biochar were influenced by the contact time and solution pH, as well as biochar specific surface area and functional groups. Adsorption of these pharmaceutical compounds was dominated by a complex interplay of three mechanisms: hydrophobic partitioning, hydrogen bonding and π–π electron donor–acceptor (EDA) interactions. Despite weaker π–π EDA interactions, reduced hydrophobicity of SPY− and increased electrostatic repulsion between anionic SPY− and the electronegative CG biochar surface at higher pH, the adsorption of SPY unexpectedly increased from 40% to 70% with an increase in pH from 7 to 10. Under alkaline conditions, adsorption was dominated by the formation of strong negative charge-assisted H-bonding between the sulfonamide moiety of SPY and surface carboxylic groups. There seemed to be no appreciable and consistent differences in the extent of DCT and ETM adsorption as the pH changed. Results suggest the CG and GB biochars could act as effective adsorbents for the removal of pharmaceuticals from reclaimed water prior to irrigation. High surface area biochars with physico-chemical properties (e.g., presence of functional groups, high cation and anion exchange capacities) conducive to strong interactions with polar-nonpolar functionality of pharmaceuticals could be used to achieve significant contaminant removal from water.Graphic

Degradation and mineralization of erythromycin by heterogeneous photocatalysis using SnO2-doped TiO2 structured catalysts: Activity and stability

Heterogeneous photocatalysis was used for the degradation and mineralization of erythromycin (ERY), with a consequent production of carboxylic acids. For that, a series of TiO2 and Ti1-xSnxO2 structured catalysts, namely M1 to M5, was prepared using the washcoating method, with the catalytic coatings being deposited onto stainless steel meshes. Besides, the catalytic activity of the prepared systems was compared to that of the commercial mesh (CM). The results showed that the prepared TiO2 structured catalyst (M1) presented better ERY oxidation than the CM one, what was associated to the higher catalyst load and to the anatase/rutile ratio. Considering the Sn-doped structured catalysts, for M2, M4 and M5 catalysts, lower ERY mineralization and high formation of carboxylic acids were found, when compared to the M3 catalyst. The improved M3 activity was attributed to the formation of a staggered gap (type II heterojunction), providing better charge separation. In this situation, a high generation of hydroxyl radicals is obtained, resulting on a higher ERY mineralization. By the obtained results it is possible to determine that the addition order and the type of Sn compound added in the washcoating process, affects the catalytic activity due to the formation of a solid solution and to the type of produced heterostructures. The M3 catalyst also showed high stability in long-term tests up to 44 h of reaction. The results provide insights into the development of an inexpensive structured catalyst production method and its influence in the stability of the photocatalyst, as well as in its applicability on water/wastewater treatment.

Characterization and clonal representation of MRSA strains in Tuzla Canton, Bosnia and Herzegovina, from 2009 to 2017.

Aim To characterize methicillin-resistant S. aureus (MRSA) strains phenotypically and genotypically and to determine their clonal affiliation, representation and antibiotic resistance profile. Methods A total of 62 randomly selected MRSA isolates of different clinical samples collected from 2009 to 2017 were phenotypically and genotypically analysed. Phenotypic analyses were performed by standard microbiological procedures, and using VITEK 2/AES instrument as well as MALDI-TOF (matrix-assisted laser desorption/ionization) technology. Genotypic characterization included spa, MLST (multilocus sequence typing) and SCCmec typing, and detection of the Panton-Valentine leukocidin (PVL) and other enterotoxin encoding genes. Results The largest number of isolates, 21 (33.87%) belonged to ST228-MRSA-I, spa type t041, t1003 and t001. Other major clones were: ST239-MRSA-III, spa type t037 and t030 (27.41%); ST8-MRSA-IV, spa type t008 and t121 (12.9%); ST247-MRSA-I, spa type t051 (4.83%). PVL was detected in 10 isolates (SCCmec IV/V). During 2009 and 2010 the most frequent MRSA strain was South German clone, ST228-MRSA-I (80% and 90%, respectively), while in later years it was replaced with Brazilian-Hungarian clone ST239-MRSA-III (75% in 2015 and 2016). The South German clone, spa type t041 in 90.48% of cases was resistant to clindamycin, ciprofloxacin, erythromycin, cefoxitin, gentamicin, kanamycin, tobramycin and penicillin, while 70.58% samples of the Brazilian-Hungarian clone spa type t037 were additionally resistant to tetracycline and rifampicin. Conclusion This research can supplement the existing knowledge about the clonal distribution of MRSA in Bosnia and Herzegovina and their sensitivity to antibiotics in order to improve the national control of these infections.

Distribution Characteristics and Risk Assessment of PPCPs in Surface Water and Aquatic Organisms in Chaoshan Coastal Area along the South China Sea

To investigate the occurrence, distribution, and potential risks of pharmaceuticals and personal care products (PPCPs) in the South costal area of China, a total of 20 PPCPs in water and aquatic organisms (fish, crab, and shellfish), obtained from 7 coastal rivers of the Chaoshan area, were determined using solid-phase extraction (SPE) and high performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS). The results showed that up to 16 to 18 kinds of PPCPs could be detected in the rivers and aquatic organisms of the Chaoshan area, and the concentrations of PPCPs in the rivers and organisms ranged from 0.30-2223 ng ·L-1 to 0.143-80.3 ng ·g-1, respectively, with a high detection rate for many pollutants. Significant differences were observed in the samples of water and organisms. The total concentration of PPCPs in the rivers of the Chaoshan area was in the order of Huanggang River > Lianjiang River > Huangjiang River > Longjiang River > Luohe River > Rongjiang River > Hanjiang River, with the dominance of sulfamethoxazole (SMX) and caffeine (CAF). The total concentrations of PPCPs in the aquatic organisms from the Huanggang River, Hanjiang River, Lianjiang River, and Luohe River were higher than the concentrations of PPCPs in the aquatic organisms from the Longjiang River and Rongjiang River, with a dominance of trimethoprim (TMP), SMX, and CAF. The total concentration of PPCPs in fish was significantly higher than that in crab and shellfish. The results of bioconcentration factor (BCF) showed that a variety of PPCPs were accumulated in the organisms from the Chaoshan rivers; among them, the BCF value in fish was higher, which was more likely to bioaccumulate than crabs and shellfish. The ecological risks in terms of risk quotient (RQ) for 12 typical PPCPs were assessed in the Chaoshan area. It was discovered that the risk for fleas and algae was significantly higher than that for fish. The RQ values of SMX, erythromycin (ERY), and sulfadiazine (SDZ) were all greater than 1, which posed potential ecological risks for algae in the Huanggang River and Lianjiang Rivers and for fleas in the Huangjiang River.

Efficacy and Safety of Enteral Erythromycin Estolate in Combination With Intravenous Metoclopramide vs Intravenous Metoclopramide Monotherapy in Mechanically Ventilated Patients With Enteral Feeding Intolerance: A Randomized, Double-Blind, Controlled Pilot Study.

In this pilot study, we aimed to determine the efficacy and safety of enteral erythromycin estolate in combination with intravenous metoclopramide compared to intravenous metoclopramide monotherapy in mechanically ventilated patients with enteral feeding intolerance. This randomized, double-blind, controlled pilot study included 35 mechanically ventilated patients with feeding intolerance who were randomly assigned to receive 10-mg metoclopramide intravenously every 6-8 hours in combination with 250-mg enteral erythromycin estolate (study group) or placebo every 6 hours for 7 days. The primary outcome was an administered-to-target energy ratio of ≥80% at 48 hours, indicating a successful feeding. Secondary, prespecified outcomes were daily average gastric residual volume (GRV), total energy intake, administered-to-target energy ratio, hospital length of stay, in-hospital mortality, and 28-day mortality. The rate of successful feeding was not significantly different between the study and placebo groups (47.1% and 61.1%, respectively; P = .51). The average daily GRV was significantly lower in the study group than in the placebo group (β = 91.58 [95% Wald CI, -164.35 to -18.8]), determined by generalized estimating equation. Other secondary outcomes were comparable, and the incidence of adverse events was not significantly different between the 2 groups. One common complication was cardiac arrhythmia, which was mostly self-terminated. Although the combination therapy of enteral erythromycin estolate and intravenous metoclopramide reduced GRV, the successful feeding rate and other patient-specific outcomes did not improve in mechanically ventilated patients with feeding intolerance.

A review of the biotransformations of priority pharmaceuticals in biological wastewater treatment processes

Wastewater effluent discharges have been considered as one of the main sources of synthetic chemicals entering into the aquatic environment. Even though they occur at low concentrations, pharmaceutically active compounds (PhACs) can have an impact on ecological toxicity that affects aquatic organisms. Moreover, new regulations in development toward preserving water quality reinforces the increasing need to monitor and abate some PhACs in wastewater treatment plants (WWTPs), where they are typically only partially eliminated. Unlike most previous reviews, we have focussed on how the main biological and chemical molecular factors impact the biotransformations of key PhACs in biological WWTP processes. Biotransformations have been found to be an important contributor towards the removal of PhACs from WWTP effluents. This review paper critically assesses these aspects and the recent advances that have been achieved in wastewater treatment processes for biodegradation of 7 PhACs; namely the non-steroidal anti-inflammatory drug (NSAID) diclofenac (DCF); the macrolide antibiotics azithromycin (AZM), erythromycin (ERY) and clarithromycin (CLR); the two natural estrogens estrone (E1) and 17β-estradiol (E2), and the synthetic estrogen 17α-ethinylesradiol (EE2). These represent the micropollutants of the EU Watch list in Decision 2015/495/EU that are most relevant to WWTPs due to their frequent detection. The metabolic pathways, transformation products and impact of relevant factors to biological WWTP processes is addressed in this review. The biokinetics of PhAC biodegradation in different engineered bioprocesses is also discussed. Promising technologies and operational strategies that are likely to have a high impact on controlling PhAC releases are highlighted and future research needs are also proposed.

Effect of Sub-MICs of Macrolides on the Sensitivity of Pseudomonas aeruginosa to Nitrosative Stress: Effectiveness against P. aeruginosa with and without Multidrug Resistance.

Sub-MICs of the 14-membered macrolides erythromycin (EM) and clarithromycin (CAM) decreased the growth of Pseudomonas aeruginosa PAO1 and increased its sensitivity to endogenous and exogenous nitrosative stress. However, a 16-membered macrolide, josamycin (JM), was not or less effective. In 9 of 13 non-multidrug-resistant P. aeruginosa (non-MDRP) and 9 of 27 MDRP ST235 strains, the sub-MIC of EM induced significant reductions in bacterial numbers following treatment with a nitric oxide donor.

Antimicrobial Resistance of Campylobacter spp. Causing Human Infection in Australia: An International Comparison.

The study investigates the prevalence of antimicrobial resistance in Campylobacter jejuni and Campylobacter coli in gastroenteritis patients in the eight most populous regions in Australia and compares the prevalence of antimicrobial resistance in Europe and North America. A total of 164 Campylobacter isolates were collected from patients with campylobacteriosis and tested for susceptibility to six antimicrobials using ETEST® strips and compared with reports from Europe and the United States. Genomes were sequenced on Illumina NextSeq to identify genetic determinants of resistance. Phenotypically, 1.8%, 14.0%, 14.6%, and 20.1% of isolates were resistant to erythromycin (ERY), ampicillin, tetracycline (TET), and ciprofloxacin (CIP), respectively. Comparing published phenotypic results of antimicrobial resistance in several European countries and the United States with these Australian isolates reveals that rates observed in Australia are among the lowest observed for ERY, CIP, and TET for both C. coli and C. jejuni. For each antimicrobial tested, concordance between resistance phenotype and genotype ranged from 66.6% to 100.0%. This study highlights that, among industrialized countries, Portugal and Spain have very high levels of antimicrobial resistance in C. jejuni and C. coli, especially when compared with the United Kingdom, United States, and Australia.

Predictive models for the degradation of 4 pharmaceutically active compounds in municipal wastewater effluents by the UV/H2O2 process

Pharmaceutically active compounds (PhACs) have been frequently detected in aquatic environment and raised concerns because of their environmental persistence and potential ecological risk, especially carbamazepine (CBZ), erythromycin (ERY), atenolol (ATL) and clofibric acid (CA). The UV/H2O2 advanced oxidation process was considered as an effective process to remove pharmaceuticals in wastewater. Because of the diverse structure of pharmaceuticals and the various wastewater matrices, this study established two models to predict the degradation of 4 PhACs in wastewater by UV/H2O2. Besides, the degradation pathway and toxicity of 4 PhACs by UV/H2O2 were explored. The degradation of 4 PhACs by UV/H2O2 followed the pseudo first-order kinetics pattern. The degradation rate of pharmaceuticals decreased as CBZ > ATL > CA > ERY. A kinetic model combining the steady state concentrations of HO∙ successfully predicted the degradation process of pharmaceuticals in 14 secondary municipal wastewater effluents. Also, a water matrix prediction model by response surface methodology (RSM) was established to estimate the degradation of pharmaceuticals well. A detailed and systematic comparison of two models in the objectives of models, predicting target contaminants, types of wastewater and parameters of models was made. In addition, the tentative transformation pathways of 4 PhACs by UV/H2O2 were proposed. 4 PhACs after UV/H2O2 treatment enhanced the toxicity, and prolongation of treatment time can reduce the toxicity on the luminescence.

Erythromycin inhibits neutrophilic inflammation and mucosal disease by upregulating DEL-1.

Macrolide antibiotics exert antiinflammatory effects; however, little is known regarding their immunomodulatory mechanisms. In this study, using 2 distinct mouse models of mucosal inflammatory disease (LPS-induced acute lung injury and ligature-induced periodontitis), we demonstrated that the antiinflammatory action of erythromycin (ERM) is mediated through upregulation of the secreted homeostatic protein developmental endothelial locus-1 (DEL-1). Consistent with the anti-neutrophil recruitment action of endothelial cell-derived DEL-1, ERM inhibited neutrophil infiltration in the lungs and the periodontium in a DEL-1-dependent manner. Whereas ERM (but not other antibiotics, such as josamycin and penicillin) protected against lethal pulmonary inflammation and inflammatory periodontal bone loss, these protective effects of ERM were abolished in Del1-deficient mice. By interacting with the growth hormone secretagogue receptor and activating JAK2 in human lung microvascular endothelial cells, ERM induced DEL-1 transcription that was mediated by MAPK p38 and was CCAAT/enhancer binding protein-β dependent. Moreover, ERM reversed IL-17-induced inhibition of DEL-1 transcription, in a manner that was dependent not only on JAK2 but also on PI3K/AKT signaling. Because DEL-1 levels are severely reduced in inflammatory conditions and with aging, the ability of ERM to upregulate DEL-1 may lead to a novel approach for the treatment of inflammatory and aging-related diseases.

Antibiotic Resistance of Legionella pneumophila in Clinical and Water Isolates-A Systematic Review.

The current systematic review investigates the antibiotic susceptibility pattern of Legionella pneumophila isolates from the 1980s to the present day, deriving data from clinical and/or water samples from studies carried out all over the world. Eighty-nine papers meeting the inclusion criteria, i.e., “Legionella pneumophila” and “resistance to antibiotics”, were evaluated according to pre-defined validity criteria. Sixty articles referred to clinical isolates, and 18 articles reported water-related L. pneumophila isolates, while 11 articles included both clinical and water isolates. Several methods have been proposed as suitable for the determination of MICs, such as the E-test, broth and agar dilution, and disk diffusion methods, in vivo and in vitro, using various media. The E-test method proposed by the European Society of Clinical Microbiology and Infectious Diseases (EUCAST) seems to be the second most frequently used method overall, but it is the preferred method in the most recent publications (2000–2019) for the interpretation criteria. Erythromycin has been proved to be the preference for resistance testing over the years. However, in the last 19 years, the antibiotics ciprofloxacin (CIP), erythromycin (ERM), levofloxacin (LEV) and azithromycin (AZM) were the ones that saw an increase in their use. A decrease in the sensitivity to antibiotics was identified in approximately half of the reviewed articles.

Wound therapy via a photo-responsively antibacterial nano-graphene quantum dots conjugate

Common bacterial pathogens have become resistant to traditional antibiotics, representing an indispensable public health crisis. Photodynamic therapy (PDT), especially when common visible light sources are used as photodynamic power, is a promising bactericidal method. Based on the special photodynamic properties triggered by commonly available light emitting diode (LED) lamps, a kind of graphene quantum dots (GQDs) based composite system (termed GQDs@hMSN(EM)) was prepared through loading both GQDs and erythromycin (EM) into the hollow mesoporous silica nanoparticle (hMSN), aiming to achieve joint antimicrobial effect. Bacterial density experiments confirmed that GQDs@hMSN(EM) had combined antimicrobial effects from photodynamic effect and drug release on Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). In animal models, the healing degree of wounds infected by bacteria also confirmed that GQDs@hMSN(EM) group had the best therapeutic effect, with the significantly reduced inflammatory factors in blood. Different from traditional GQDs synthesized by solvothermal method, the as-prepared GQDs@hMSN can produce singlet oxygen (1O2) under light exposure to destroy the structure of bacteria, thus achieving highly efficient antimicrobial effect. The GQDs@hMSN(EM) in this work possesses good antimicrobial activity, sufficient drug loading, and controllable drug release ability, which provides a new opportunity for GQDs-based nanoplatform to enhance antimicrobial effect and reduce their drug resistance.

Energy-efficient erythromycin degradation using UV-LED (275 nm)/chlorine process: Radical contribution, transformation products, and toxicity evaluation

In this study, we investigated the degradation mechanism of erythromycin (ERY) during UV-LED/chlorine treatment using a 275-nm ultraviolet light-emitting diode (UV-LED). This wavelength is known to generate fewer disinfection byproducts (DBPs), and to have higher energy and photon yield efficiency compared to low pressure mercury (LP-UV) lamp which emits 254 nm of UV radiation. The degradation of ERY during the UV-LED/chlorine reaction followed pseudo-first-order kinetics. While Cl• and ClO• radicals along with other secondary radicals played key roles in the degradation of ERY at alkaline pH conditions, •OH radical was the main contributor at acidic pH conditions. Using ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QToF-MS), we tentatively identified six byproducts. Trace amounts of DBPs, such as chloroform (CHCl3) and chlorate (ClO3−) ions, were also detected at less than 0.3 mg/L. There was no residual antibiotic effect at the end of the UV-LED/chlorine reaction due to the complete degradation of important moieties, such as macrolide, in ERY. Toxicity decreased by 20% after 20 min during the UV-LED/chlorine process of ERY (1.0 mg/L) degradation. Finally, we confirmed the inactivation of ARB and ARG during the UV-LED/chlorine process.

Predicting DNA binding protein-drug interactions based on network similarity

BackgroundThe study of DNA binding protein (DBP)-drug interactions can open a breakthrough for the treatment of genetic diseases and cancers. Currently, network-based methods are widely used for protein-drug interaction prediction, and many hidden relationships can be found through network analysis. We proposed a DCA (drug-cluster association) model for predicting DBP-drug interactions. The clusters are some similarities in the drug-binding site trimmers with their physicochemical properties. First, DBPs-drug binding sites are extracted from scPDB database. Second, each binding site is represented as a trimer which is obtained by sliding the window in the binding sites. Third, the trimers are clustered based on the physicochemical properties. Fourth, we build the network by generating the interaction matrix for representing the DCA network. Fifth, three link prediction methods are detected in the network. Finally, the common neighbor (CN) method is selected to predict drug-cluster associations in the DBP-drug network model.ResultThis network shows that drugs tend to bind to positively charged sites and the binding process is more likely to occur inside the DBPs. The results of the link prediction indicate that the CN method has better prediction performance than the PA and JA methods. The DBP-drug network prediction model is generated by using the CN method which predicted more accurately drug-trimer interactions and DBP-drug interactions. Such as, we found that Erythromycin (ERY) can establish an interaction relationship with HTH-type transcriptional repressor, which is fitted well with silico DBP-drug prediction.ConclusionThe drug and protein bindings are local events. The binding of the drug-DBPs binding site represents this local binding event, which helps to understand the mechanism of DBP-drug interactions.