Occurrence, genetic characterization, and antibiotic susceptibility of Cronobacter spp. isolated from low water activity functional foods in Brazil.

Cronobacter spp. are bacterial pathogens isolated from a wide variety of foods. This study aims at evaluating the occurrence of Cronobacter spp. in low water activity functional food samples, detect the presence of virulence genes, and determine the antibiotic susceptibility of strains. From 105 samples, 38 (36.2%) were contaminated with Cronobacter spp. The species identified by polymerase chain reaction (PCR) and sequencing analyses (rpoB and fusA genes, respectively) were C. sakazakii (60.3%), C. dublinensis (25.4%), C. turincensis (9.5%), and C. malonaticus (4.8%). Nineteen fusA alleles were identified, including four new alleles. The virulence genes were identified by PCR and all isolates were positive for ompX and sodA genes, 60.3% to cpa gene, and 58.7% to hly gene. Using the disk diffusion method, antibiotic susceptibility to twelve antibiotics was assessed twice, separated by a 19-month period. In the first test, the isolates showed diverse antibiotic susceptibility profiles, with nineteen isolates (30.2%) being multi-drug resistant (resistant to three or more antibiotic classes), in the second, the isolates were susceptible to all antibiotics. Cronobacter spp. in functional foods demonstrates the need for continued investigation of this pathogen in foods, and further research is needed to clarify the loss of resistance of Cronobacter strains.

Mechanistic insight into the synergistic antimicrobial potential of Fagonia indica Burm.f. extracts with cefixime.

Fagonia indica Burm.f. is known for its anti-infective character and has been studied in the present work as a synergistic remedy against resistant bacterial strains. Initially, phytochemicals were quantified in n-Hexane (n-Hex), ethyl acetate (E.A), methanol (MeOH), and aqueous (Aq.) extracts by Total Phenolic Content (TPC), Total Flavonoid Content (TFC) and Reverse Phase High Performance Liquid Chromatography (RP-HPLC) analysis. Later, after establishing an antibacterial resistance profile for extracts and antibiotics against gram-positive and gram-negative strains, synergism was evaluated in combination with cefixime through time-kill kinetics and bacterial protein estimation studies. Topographic images depicting synergism were obtained by scanning electron microscopy for Methicilin-resistant Staphylococcus aureus (MRSA) and Resistant Escherichia coli (R.E. coli). Results showed the presence of maximum phenolic (28.4 ± 0.67 µg GAE/mg extract) and flavonoid (11 ± 0.42 µg QE/mg extract) contents in MeOH extract. RP-HPLC results also displayed maximum polyphenols in MeOH extract followed by E.A extract. Clinical strains were resistant to cefixime whereas these were moderately inhibited by all extracts (MIC 150-300 µg/ml) except Aq. extract. E.A and n-Hex extracts demonstrated maximum synergism (Fractional inhibitory concentration index (FICI) 0.31) against R.E. coli. The n-Hex extract displayed total synergism against R.P. a with a 4-fold reduction in cefixime dose. Time-kill kinetics showed maximum inhibition of gram-negative bacterial growth from 3 to 12 h when treated at FICI and 2FICI values with > 10-fold reduction of the extracts' dose. All combinations demonstrate > 70 % protein content inhibition with bacterial cell wall disruption in SEM images. Fortunately, FICI concentrations have low hemolytic potential (<5%). Conclusively, F. indica extracts can mitigate antimicrobial resistance against cefixime and can be investigated in detail by in vivo and mechanistic studies.

Synthesis of Bimetallic BiPO4/ZnO Nanocomposite: Enhanced Photocatalytic Dye Degradation and Antibacterial Applications.

Multidrug-resistant strains (MDRs) are becoming a major concern in a variety of settings, including water treatment and the medical industry. Well-dispersed catalysts such as BiPO4, ZnO nanoparticles (NPs), and different ratios of BiPO4/ZnO nanocomposites (NCs) were synthesized through hydrothermal treatments. The morphological behavior of the prepared catalysts was characterized using XRD, Raman spectra, PL, UV-Vis diffuse reflectance spectroscopy (UV-DRS), SEM, EDX, and Fe-SEM. MDRs were isolated and identified by the 16s rDNA technique as belonging to B. flexus, B. filamentosus, P. stutzeri, and A. baumannii. The antibacterial activity against MDRs and the photocatalytic methylene blue (MB) dye degradation activity of the synthesized NPs and NCs were studied. The results demonstrate that the prepared BiPO4/ZnO-NCs (B1Z4-75:300; NCs-4) caused a maximum growth inhibition of 20 mm against A. baumannii and a minimum growth inhibition of 12 mm against B. filamentosus at 80 µg mL-1 concentrations of the NPs and NCs. Thus, NCs-4 might be a suitable alternative to further explore and develop as an antibacterial agent. The obtained results statistically justified the data (p ≤ 0.05) via one-way analysis of variance (ANOVA). According to the results of the antibacterial and photocatalytic study, we selected the best bimetallic NCs-4 for the photoexcited antibacterial effect of MDRs, including Gram ve+ and Gram ve- strains, via UV light irradiation. The flower-like NCs-4 composites showed more effectiveness than those of BiPO4, ZnO, and other ratios of NCs. The results encourage the development of flower-like NCs-4 to enhance the photocatalytic antibacterial technique for water purification.

Current State of Knowledge Regarding WHO High Priority Pathogens-Resistance Mechanisms and Proposed Solutions through Candidates Such as Essential Oils: A Systematic Review.

Combating antimicrobial resistance (AMR) is among the 10 global health issues identified by the World Health Organization (WHO) in 2021. While AMR is a naturally occurring process, the inappropriate use of antibiotics in different settings and legislative gaps has led to its rapid progression. As a result, AMR has grown into a serious global menace that impacts not only humans but also animals and, ultimately, the entire environment. Thus, effective prophylactic measures, as well as more potent and non-toxic antimicrobial agents, are pressingly needed. The antimicrobial activity of essential oils (EOs) is supported by consistent research in the field. Although EOs have been used for centuries, they are newcomers when it comes to managing infections in clinical settings; it is mainly because methodological settings are largely non-overlapping and there are insufficient data regarding EOs' in vivo activity and toxicity. This review considers the concept of AMR and its main determinants, the modality by which the issue has been globally addressed and the potential of EOs as alternative or auxiliary therapy. The focus is shifted towards the pathogenesis, mechanism of resistance and activity of several EOs against the six high priority pathogens listed by WHO in 2017, for which new therapeutic solutions are pressingly required.

Selected N-Terpenyl Organoselenium Compounds Possess Antimycotic Activity In Vitro and in a Mouse Model of Vulvovaginal Candidiasis.

In the present work, a series of N-terpenyl organoselenium compounds (CHB1-6) were evaluated for antimycotic activity by determining the minimum inhibitory concentration (MIC) for each compound in fluconazole (FLU)-sensitive (S1) and FLU-resistant (S2) strains of Candida albicans (C. albicans). The most active compounds in the MIC screen were CHB4 and CHB6, which were then evaluated for cytotoxicity in human cervical cancer cells (KB-3-1) and found to be selective for fungi. Next, CHB4 and CHB6 were investigated for skin irritation using a reconstructed 3D human epidermis and both compounds were considered safe to the epidermis. Using a mouse model of vulvovaginal candidiasis (VVC), CHB4 and CHB6 both exhibited antimycotic efficacy by reducing yeast colonization of the vaginal tract, alleviating injury to the vaginal mucosa, and decreasing the abundance of myeloperoxidase (MPO) expression in the tissue, indicating a reduced inflammatory response. In conclusion, CHB4 and CHB6 demonstrate antifungal activity in vitro and in the mouse model of VVC and represent two new promising antifungal agents.

Molecular Characterization of Bacterial Isolates from Soil Samples and Evaluation of their Antibacterial Potential against MDRS.

Some soil microbes, with their diverse inhabitance, biologically active metabolites, and endospore formation, gave them characteristic predominance and recognition among other microbial communities. The present study collected ten soil samples from green land, agricultural and marshy soil sites of Khyber Pakhtunkhwa, Pakistan. After culturing on described media, the bacterial isolates were identified through phenotypic, biochemical and phylogenetic analysis. Our phylogenetic analysis revealed three bacterial isolates, A6S7, A1S6, and A1S10, showing 99% nucleotides sequence similarity with Brevibacillus formosus, Bacillus Subtilis and Paenibacillus dendritiformis. The crude extract was prepared from bacterial isolates to assess the anti-bacterial potential against various targeted multidrug-resistant strains (MDRS), including Acinetobacter baumannii (ATCC 19606), Methicillin-resistant Staphylococcus aureus (MRSA) (BAA-1683), Klebsiella pneumoniae (ATCC 13883), Pseudomonas aeruginosa (BAA-2108), Staphylococcus aureus (ATCC 292013), Escherichia coli (ATCC25922) and Salmonella typhi (ATCC 14028). Our analysis revealed that all bacterial extracts possess activity against Gram-negative and Gram-positive bacteria at a concentration of 5 mg/mL, efficiently restricting the growth of E. coli compared with positive control ciprofloxacin. The study concluded that the identified species have the potential to produce antimicrobial compounds which can be used to control different microbial infections, especially MDRS. Moreover, the analysis of the bacterial extracts through GC-MS indicated the presence of different antimicrobial compounds such as propanoic acid, oxalic acid, phenol and hexadecanoic acid.

[Project to Reduce Cases of Drug-Resistant Strain Colonization in the Intensive Care Unit Using a Chlorhexidine Gluconate Bath].

BACKGROUND: Drug-resistant strains of bacteria are associated with severe consequences such as bacteremia, shock, and death, and increase hospital stay durations and medical health expenses. Therefore, reducing the spread of drug-resistant strains is a priority concern. PURPOSE: This project was developed to reduce the number of colonization cases of drug-resistant strains and subsequently increase the quality of care provided in our intensive care unit. RESOLUTIONS: In this project, a chlorhexidine gluconate (CHG) bath standard protocol and CHG bath skill checklist were established, education and training courses were planned, a regular bed curtain replacement schedule and sink cleaning protocols were implemented, and regular audits were conducted. RESULTS: Immediately following project implementation (October - December 2018), the average monthly cases of Vancomycin-resistant enterococci colonization decreased from 6.08 to 4.33, and the average monthly cases of multi-drug resistant Acinebacter baumannii colonization decreased from 4.08 to 1.33. Furthermore, between January and July 2019, the average monthly cases of colonization for the abovementioned bacteria numbered 4 and 0.86, respectively, which met the level of reduction targeted in this project. CONCLUSIONS: The results of this project indicate that implementing CHG bed baths is effective in reducing the incidence of drug resistant strain colonization and rate of related infections in patients. CHG bed baths should be applied clinically to improve the quality of intensive care.

Adaptation to Antimicrobials and Pathogenicity in Mycoplasmas: Development of Ciprofloxacin-Resistance and Evolution of Virulence in Acholeplasma laidlawii.

For the first time it was shown that the development of resistance to ciprofloxacin in vitro in Acholeplasma laidlawii, a mycoplasma which is widely spread in nature and which is the main contaminant of cell cultures and vaccines, is associated with diverse pathways of virulence evolution: virulome and virulence differ significantly between ciprofloxacin-resistant strains, including those with the same level of antimicrobial resistance.

Synthesis and anti-pseudomonal activity of new ß-Ala modified analogues of the antimicrobial peptide anoplin.

Due to the rise of antibiotic-resistant bacteria around the world, AMPs (antimicrobial peptides), depending on non-specific membrane mechanism and low tendency to develop bacterial resistance, attract widespread attentions as novel antimicrobial alternatives for treating bacterial infections. In this study, a series of new ß-Ala modified-antimicrobial peptide analogues of anoplin were designed and synthesized, and their biological activities were described. Most of the new peptides showed perfect antimicrobial activities against two antibiotic-sensitive Pseudomonas aeruginosa strains and three clinical isolates of multidrug-resistant P. aeruginosa strains without significant hemolysis or cytotoxicity. More significantly, Ano-1ß and Ano-8ß (substituting positions 1 and 8 of anoplin with ß-Ala, respectively) exhibited the best antimicrobial potency. Additionally, the two new peptides were stable under physiological conditions and displayed preferable in vivo antimicrobial activity with less acute toxicity. Notably, Ano-1ß and Ano-8ß hardly generated resistance in contrast to conventional antibiotics rifampicin and gentamicin, and they exhibited better anti-biofilm activity and synergistic or additive effects in combination with conventional antibiotics. What's more, Ano-1ß and Ano-8ß had strong membrane disruption as evidenced by outer membrane permeabilization and cytoplasmic membrane depolarization assays. Confocal laser scanning microscopy and scanning electron microscopy further demonstrated that the two new peptides could destroy the bacterial membrane integrity. Collectively, the incorporation of ß-Ala was a reasonable approach for new antimicrobial peptides design, and the new peptides Ano-1ß and Ano-8ß might be promising antimicrobial candidates in combating the increasing antibiotic-resistant bacteria.

Molecular characterization of serine/threonine protein phosphatase of Eimeria tenella.

Avian coccidiosis is a widespread and economically significant poultry disease caused by several Eimeria species, including Eimeria tenella. Previously, E. tenella serine/threonine protein phosphatase (EtSTP) was found to be differentially expressed in drug-sensitive (DS) and drug-resistant strains using RNA-seq. In the present study, we found that transcription and translation levels of EtSTP were higher in diclazuril-resistant (DZR) strains and maduramicin-resistant (MRR) strains than in DS strains using quantitative real-time PCR (qPCR) and Western blotting. Enzyme activity results indicated that the catalytic activity of EtSTP was higher in the two drug-resistant strains than in DS strains. Western blot and qPCR analysis also showed that expression levels of EtSTP were higher in unsporulated oocysts (UO) and second-generation merozoites (SM). Indirect immunofluorescence localization showed that EtSTP was located in most areas of the parasite with the exception of refractile bodies, and fluorescence intensity was enhanced during development. In vitro inhibition experiments showed that the ability of sporozoites (SZ) to invade cells was significantly decreased after treatment with anti-rEtSTP antibody. These results indicated that EtSTP acted mainly during the developmental and reproductive stages of the parasite and may be related to the resistance of coccidia to external drug pressure.

Antibiofilm coatings through atmospheric pressure plasma for 3D printed surgical instruments.

Recently, medical applications for 3D printing are expanding rapidly and are expected to revolutionize health care, specifically, manufacturing surgical guides and protective face mask against coronavirus (COVID-19). These instruments come in contact with the human tissues, being necessary 3D printed materials free of pathogenic microbes or other contaminants. Therefore, they must be sterilized to avoid that bacteria can attach to the surface and produce biofilm. With the aim of avoiding bacterial biofilm formation and minimize the health risks, acrylic acid (AcAc) coatings applied by plasma-polymerization have been deposited on 3D printed polylactic acid (PLA) Petri dishes. Six antimicrobial-resistant clinical and two susceptible control strains of Pseudomonas aeruginosa and Staphylococcus aureus species were analyzed. AcAc coatings provide the surface with greater hydrophilicity and, consequently, the formation of a hydration layer, whose thickness is related to the surface roughness. This hydration layer could explain the reduction of bacterial attachment and, consequently, the biofilm formation. Antibiofilm coatings are more successful against P. aeruginosa strains than against S. aureus ones; due to some coatings presents a smaller topography scale than the P. aeruginosa length, reducting the contact area between the bacteria and the coating, and causing a potential rupture of the cellular membrane. AcAc coatings with less number of plasma passes were more effective, and showed up to a 50% relative biofilm reduction (in six of the eight strains studied) compared with the untreated plates.

The Effect of Antibiotic-Cycling Strategy on Antibiotic-Resistant Bacterial Infections or Colonization in Intensive Care Units: A Systematic Review and Meta-Analysis.

BACKGROUND: Antibiotic-resistant bacteria, especially multidrug-resistant strains, play a key role in impeding critical patients from survival and recovery. The effectiveness of the empiric use of antibiotics in the circling manner in intensive care units (ICUs) has not been analyzed in detail and remains controversial. Therefore, this systematic review and meta-analysis were conducted to evaluate antibiotic-cycling effect on the incidence of antibiotic-resistant bacteria. METHODS: We searched PubMed, Embase, the Cochrane Central Register of Controlled Trials, and Web of Science for studies focusing on whether a cycling strategy of empiric use of antibiotics could curb the prevalence of antibiotic-resistant bacteria in ICUs. The major outcomes were risk ratios (RRs) of antibiotic-resistant infections or colonization per 1,000 patient days before and after the implementation of antibiotic cycling. A random-effects model was adopted to estimate results in consideration of clinical heterogeneity among studies. The registration number of the meta-analysis is CRD42018094464. RESULTS: Twelve studies, involving 2,261 episodes of resistant infections or colonization and 160,129 patient days, were included in the final analysis. Based on the available evidence, the antibiotic-cycling strategy did not reduce the overall incidence of infections or colonization with resistant bacteria (RR = 0.823, 95% CI 0.655-1.035, p = .095). In subgroup analyses, the cycling strategy cut down the incidence of resistant bacteria more significantly than baseline period (p = .028) but showed no difference in comparison with mixing strategy (p = .758). LINKING EVIDENCE TO ACTION: Although the cycling strategy performed better than relatively free usage of antibiotics in the baseline period on reducing resistant bacteria, the cycling strategy did not show advantage when compared with the mixing strategy in subgroup analyses. In addition, these viewpoints still need more evidence to confirm.

Risk factors for mortality in patients with Stenotrophomonas maltophilia bacteremia and clinical impact of quinolone-resistant strains.

BACKGROUND: Stenotrophomonas maltophilia is an important nosocomial pathogen. This pathogen has intrinsic or acquired resistance to a number of antibiotics classes. Furthermore, Stenotrophomonas infections have been associated with high mortality, mainly in immunocompromised patients. Accordingly, we conducted a retrospective cohort study on the clinical data, microbiological characteristics, and outcomes of patients with S. maltophilia (SM) bacteremia. METHODS: A retrospective cohort study was conducted at two tertiary care referral hospitals in Seoul, South Korea. Data were collected between January 2006 and December 2015 from electric medical records. Our analysis aimed to identify the risk factors associated with crude mortality, as well as the predictive factors of quinolone-resistant strains in SM bacteremia patients. RESULTS: A total of 126 bacteremia patients were enrolled in the study. The mortality rate was 65.1%. On multivariable analysis, hypoalbuminemia (odds ratio [OR], 5.090; 95% confidence interval [CI], 1.321-19.621; P = 0.018), hematologic malignancy (OR, 35.567; 95% CI, 2.517-502.515; P = 0.008) and quinolone-resistant strains (OR, 7.785; 95% CI, 1.278-47.432; P = 0.026) were independent risk factors for mortality. Alternatively, usage of an empirical regimen with quinolone (OR, 0.172; 95% CI, 0.034-0.875; P = 0.034) was an independent protective factor for mortality. The multivariable analysis of predictive factors revealed that high Charlson comorbidity index (OR, 1.190; 95% CI, 1.040-1.361; P = 0.011) and indwelling of a central venous catheter (CVC) (OR, 3.303; 95% CI, 1.194-9.139; P = 0.021) were independent predisposing factors associated with quinolone-resistant strains in SM bacteremia patients. CONCLUSIONS: Our findings suggest that a high Charlson comorbidity score and indwelling of a CVC were significantly independent predictors of quinolone-resistant strains in SM bacteremia patients. Therefore, we need to carefully consider the antibiotic use in SM bacteremia patients with these predictive factors.

Effects of iron oxide (Fe3 O4 ) nanoparticles on Escherichia coli antibiotic-resistant strains.

AIMS: Antibiotic resistance of different bacteria requires the development of alternative approaches for overcoming this phenomenon. The antibacterial effects of iron oxide (Fe3 O4 ) nanoparticles (NPs) (from 50 to 250 µg ml-1 ) on Escherichia coli antibiotic-resistant strains have been aimed. METHODS AND RESULTS: The study was performed with ampicillin-resistant E. coli DH5α-pUC18 and kanamycin-resistant E. coli pARG-25 stains. Specific growth rate of bacteria (µ), lag phase duration and colony-forming units (CFU) were determined to evaluate growth properties. Fe3 O4 NPs (average size of 10·64 ± 4·73 nm) coated with oleic acid and synthesized by modified co-precipitation method were used. The medium pH, H+ efflux, membrane H+ conductance, redox potential determinations and H2 yield assay were done using potentiometer methods. Growth properties were changed by NPs in concentration-dependent manner. NPs decreased (up to twofold) H+ -fluxes through bacterial membrane more in E. coli in the presence of the N,N'-dicyclohexylcarbodiimide, inhibitor of ATPase, indicating that antibacterial activity of these NPs was connected with ATP-associated metabolism. Membrane-associated H2 production was lowered up to twofold. Moreover, the synergetic interactions of NPs and antibiotics were found: combination of NPs and antibiotics provided the higher H+ conductance, lower H+ -fluxes and H2 yield. CONCLUSIONS: Fe3 O4 NPs can be suggested as alternative antibacterial agents, which can substitute antibiotics in different applications. SIGNIFICANCE AND IMPACT OF THE STUDY: The antibacterial effects of Fe3 O4 NPs on the growth properties and membrane activity of E. coli antibiotic-resistant strains have been demonstrated. These NPs have potential as antibacterial agents, which can substitute for antibiotics in bacterial disease treatment in biomedicine, pharmaceutical and environmental applications.

Design, synthesis and molecular modeling studies on novel moxifloxacin derivatives as potential antibacterial and antituberculosis agents.

Twenty-one novel alkyl/acyl/sulfonyl substituted fluoroquinolone derivatives were designed, synthesized and evaluated for their anti-tuberculosis and antibacterial activity. The targeted compounds were synthesized by the introduction of alkyl, acyl or sulfonyl moieties to the basic secondary amine moiety of moxifloxacin. Structures of the compounds were enlightened by FT-IR, 1H NMR, 13C NMR and HRMS data besides elemental analysis. Compounds were initially tested in vitro for their anti-mycobacterial activity against Mycobacterium tuberculosis H37Rv using microplate alamar blue assay. Minimal inhibitory concentration (MIC) values of all compounds were found between > 25.00-0.39 µg/mL while compounds 1, 2 and 13 revealed an outstanding activity against M. tuberculosis H37Rv with MIC values of 0.39 µg/mL. Activities of compounds 1-21 against to a number of Gram-positive and Gram-negative bacteria and fast growing mycobacterium strain were also investigated by agar well diffusion and microdilution methods. According to antimicrobial activity results, compound 13 was found the most potent derivative with a IC50 value of <1.23 µg/mL against Staphylococcus aureus and clinical strain of methicillin-resistant clinical strain of S. aureus.

In vitro evaluation of anthraquinones from Aloe vera (Aloe barbadensis Miller) roots and several derivatives against strains of influenza virus.

Aloe vera is a crop of wide economic value of worldwide distribution, and a rich source of quinone components. Recently, antiviral aloe anthraquinones had been reported against human influenza virus. In the present work two anthraquinones, aloesaponarin-I (1) and aloesaponarin-II (2) were isolated from A. vera roots, and six derivatives were obtained by methylation (3), acetylation (4) and O-glycosyl (5-6) reactions starting from (1). Additionally, a new Tetra-O-acetyl-ß-d-glucopyranosyl derivative from 2 was also prepared. All compounds were evaluated against two strains of influenza virus AH1N1 by cytopathic effect reduction assay (CPE). The antiviral activity was determined by the ability of compounds to inhibit virus replication on Madin Darby Canine Kidney cells (MDCK). New derivatives 3-(2´,3´,4´,6´-Tetra-O-acetyl-ß-d-glucopyranosyl-aloesaponarin-I (5) and 3-(2´,3´,4´,6´-Tetra-O-acetyl-ß-d-glucopyranosyl- aloesaponarin-II (7) showed a cytopathic reduction effect against influenza strain A/Yucatán/2370/09 with IC50 of 30.77 and 13.70 µM, and against the virus A/Mexico/InDRE797/10 with IC50 of 62.28 and 19.47 µM, respectively. To assess the effect of derivatives 5 and 7 during one cycle of replication (0-10 h), a time-of-addition experiment was performed. As a result it was found that both compounds were most effective when added 6-10 h post-infection and significantly inhibited viral titre (> 70%) at the concentrations of 50 and 100 µM. Based on the structural analysis of the compounds, it was suggested that the Tetra-O-acetyl-ß-d-glucopyranosyl substituent at the C3 position of the anthraquinone might have an effect against the influenza AH1N1 virus.

Potent Antitrypanosomal Activities of 3-Aminosteroids against African Trypanosomes: Investigation of Cellular Effects and of Cross-Resistance with Existing Drugs.

Treatment of animal African trypanosomiasis (AAT) requires urgent need for safe, potent and affordable drugs and this has necessitated this study. We investigated the trypanocidal activities and mode of action of selected 3-aminosteroids against Trypanosoma brucei brucei. The in vitro activity of selected compounds of this series against T. congolense (Savannah-type, IL3000), T. b. brucei (bloodstream trypomastigote, Lister strain 427 wild-type (427WT)) and various multi-drug resistant cell lines was assessed using a resazurin-based cell viability assay. Studies on mode of antitrypanosomal activity of some selected 3-aminosteroids against Tbb 427WT were also carried out. The tested compounds mostly showed moderate-to-low in vitro activities and low selectivity to mammalian cells. Interestingly, a certain aminosteroid, holarrhetine (10, IC50 = 0.045 ± 0.03 µM), was 2 times more potent against T. congolense than the standard veterinary drug, diminazene aceturate, and 10 times more potent than the control trypanocide, pentamidine, and displayed an excellent in vitro selectivity index of 2130 over L6 myoblasts. All multi-drug resistant strains of T. b. brucei tested were not significantly cross-resistant with the purified compounds. The growth pattern of Tbb 427WT on long and limited exposure time revealed gradual but irrecoverable growth arrest at ≥ IC50 concentrations of 3-aminosteroids. Trypanocidal action was not associated with membrane permeabilization of trypanosome cells but instead with mitochondrial membrane depolarization, reduced adenosine triphosphate (ATP) levels and G2/M cell cycle arrest which appear to be the result of mitochondrial accumulation of the aminosteroids. These findings provided insights for further development of this new and promising class of trypanocide against African trypanosomes.

[Antibiotic resistance in patients after serial intravitreal injections]. / Rezistentnost' k antibiotikam u patsientov na fone mnogokratnykh intravitreal'nykh in''ektsii.

Despite the lack of convincing data on the effectiveness of antibiotic therapy in the prevention of Post-Injection Endophthalmitis (PIE), the use of topical antibiotics for intravitreal injections is still a common practice. Frequent, monthly use of antibiotics results in changes of the composition of conjunctival flora and spontaneous mutations of bacteria, and leads to selective survival of resistant and virulent strains that can cause serious damage inside the eye.

[Conjunctival microflora and its antibiotic sensitivity after serial intravitreal injections]. / Mikroflora kon''iunktivy i ee chuvstvitel'nost' k antibiotikam posle mnogokratnykh intravitreal'nykh in''ektsii.

INTRODUCTION: The approach to post-procedure management of patients undergoing intravitreal injections should be unified and consistent. Frequent use of antibiotic drugs leads to generation of resistant conjunctival strains. PURPOSE: To study the composition of conjunctival microflora and its antibiotic susceptibility in patients who received 20 or more intravitreal injections and concomitant antibiotic therapy, and in a group of patients of the same age without history of intravitreal injections or ophthalmological operations. MATERIAL AND METHODS: A total of 40 inoculations were performed (20 patients in each group, 40 eyes). In case of culture growth, species identification and antibiotic sensitivity of the microorganisms were investigated using automated identification and susceptibility testing system BD Phoenix 100. RESULTS: Culture growth was observed in 70% of the control group patients. All isolated microorganisms were different types of staphylococci - Staphylococcus epidermidis (78.57%), S. caprae (7.14%), S. hominis (7.14%), and S. aureus (7.14%). In the second group, we observed culture growth in 55% of cases. Eleven cultures were Gram-positive bacteria: S. epidermidis (72.73%), S. haemolyticus (18.18%), S. aureus (9.09%). Gram-negative Pseudomonas aeruginosa was detected in 1 patient. In the control group, multi-resistant cultures accounted for 42.86%. In the group of patients with multiple intravitreal injections, 75% of cases showed multiresistance (9 out of 12 isolates). In the group of patients who have undergone 20 or more injections, greatest resistance was observed to penicillin G, doxycycline, gentamicin, erythromycin, clindamycin, moxifloxacin, fusidic acid, chloramphenicol, and trimethoprim/sulfamethoxazole compared to the control group. CONCLUSION: Overuse of antibiotics in the management of patients receiving intravitreal injections leads to selection of resistant strains.

[New possibilities in antibacterial treatment of intra-abdominal infections caused by multiresistant microflora]. / Novye vozmozhnosti antibakterial'noi terapii intraabdominal'nykh infektsii, vyzvannykh polirezistentnoi mikrobnoi floroi.

AIM: To determine the place of new drugs with activity against multidrug resistant strains of microorganisms in the treatment of complicated intraabdominal infections. MATERIAL AND METHODS: The incidence and distribution of pathogens isolated from intra-abdominal specimens in patients with intra-abdominal infections are analyzed. RESULTS: The current situation on the growth of resistant strains among pathogens causing intra-abdominal infections is rewied. New combined drugs for the treatment of multidrug resistant infections - ceftolozane/tazobactam and ceftazidim/avibactam plus metronidazole, has been suggested. Their potential role in empiric and targeted antibacterial treatment of complicated intraabdominal infections is defined. CONCLUSION: Taking into consideration local monitoring data and risk factors of multi resistant strains Ceftolozane/tazobactam in combination with metronidazole can be used in empiric regime of treatment. Due to the high activity on carbapenem resistant strains of Klebsiella pneumonia and the lack of alternatives, it is advisable to use Ceftazidim/avibactam for the targeted therapy.