Green Synthesized Iron-Coated Silver Nanoparticles: Economic Bimetallic Nanoparticles Potential Against Methicillin-Resistance Staphylococcus aureus

Iron coating was introduced as one of the novel techniques to improve physicochemical and biological properties of silver nanoparticles (AgNPs). In the current experiment, impact of iron coating on the antimicrobial potency of AgNPs was investigated against methicillin-resistance Staphylococcus aureus (MRSA). To obtain more accurate data about the antimicrobial potency of examined nanostructures, the experiment was done on the 10 isolates of MRSA which were isolated from skin lesions. AgNPs and iron-coated AgNPs (Fe@AgNPs) were fabricated based on a green one-pot reaction procedure. Minimal inhibitory concentration (MIC) of Fe@AgNPs was not significantly different with MIC of AgNPs against eight out of 10 examined MRSA isolates. Also, by iron coating a reduction in the minimal inhibitory concentration (MIC) of AgNPs was observed against two MRSA isolates. The average MIC of AgNPs against 10 MRSA isolates was calculated to be 2.16 ± 0.382 mg/mL and this value was reduced to 1.70 ± 0.638 mg/mL for Fe@AgNPs. However, this difference was not considered significant statistically (P-value > 0.05). From productivity point of view, it was found that iron coating would improve the productivity of the synthesis reaction more than fivefold. Productivity of AgNPs was calculated to be 1.02 ± 0.07 g/L, meanwhile this value was 5.25 ± 0.05 g/L for Fe@AgNPs. Iron coating may provide another economic benefit to reduce final price of AgNPs. It is obvious that the price of a particular nanostructure made of silver and iron is significantly lower than that of pure silver. These findings can be considered for the fabrication of economic and potent antimicrobial nanoparticles.

The Response of Susceptible and Pyrethroid-Resistant Blattella germanica (Dyctioptera: Blattellidae) to Shelter-Associated Cues

In this work, it was studied the role of faeces in the location and permanence in a shelter in susceptible and pyrethroid-resistant individuals of Blattella germanica (Linnaeus 1767). Additionally, the effect of different concentrations of palmitic acid on the modulation of these behaviours was tested. A shelter constituted by a square cardboard structure was offered to susceptible as well as to resistant specimens. The shelter bases were treated with faecal extracts obtained from susceptible or resistant cockroaches, or with solutions of palmitic acid. The behaviour of susceptible as well as resistant specimens was analysed using infrared videography software. Susceptible's faecal extract attracted both specimens since the time spent by cockroaches to locate the treated shelters was lower, whereas the faecal extract from resistant insects did not elicit any effect on both strains. Faecal extracts showed an arrestant effect on both strains, suggested by the time spent inside the shelter that was significantly higher in their presence. On the other hand, treatment with palmitic acid produced an attractant or a repellent effect depending on the concentration and strain. The tested lower concentration was attractant to susceptible insects, but did not produce any effect on resistant ones. In addition, the higher concentrations did not produce any effect on susceptible individuals, but resulted repellent for resistant ones. Palmitic acid did not produce an arrestant effect on the strains as there was not an increase in time spent inside the shelter in the presence of this substance. An increase in the number of visits to the shelter and to the periphery was also observed in shelters treated with the faecal extract and with the lower concentration of palmitic acid. These results show that compounds of the susceptible faeces were attractant to cockroaches of both strains, while faecal extracts from resistant insects were not. Moreover, a dual effect of palmitic acid was observed, being attractant at low concentrations and repellent as concentration increased. Additionally, a difference in the concentration threshold at which the effect of this substance changes was observed between strains.

Molecular characterization and analysis of drug resistance-associated protein enolase 2 of Eimeria tenella

Eimeria tenella, an intestinal parasite, has brought huge economic losses to the poultry industry. The prevalence and severity of the development of drug resistance has increased the challenge of coccidiosis control. We previously identified the enolase 2 of E. tenella (EtENO2) was differentially expressed in drug-sensitive (DS) and drug-resistant strains using RNA-seq. In this study, the expression of EtENO2 in diclazuril-resistant (DZR), maduramicin-resistant (MRR), and salinomycin-resistant (SMR) strains was analyzed by quantitative real-time PCR (qRT-PCR) and western blots. EtENO2 was highly expressed in several drug-resistant strains compared with the DS strain. The qRT-PCR showed that the transcription level of EtENO2 in the field-isolated resistant strains was upregulated compared with the DS strain. The enzyme activity results indicated that the catalytic activity of EtENO2 in the drug-resistant strains was higher than in the DS strain. In addition, qRT-PCR and western blots showed that the expression level of EtENO2 was higher in second generation merozoites (SM) and unsporulated oocysts (UO) than that in sporozoites (SZ) and sporulated oocysts (SO). Immunofluorescence localization revealed that EtENO2 was distributed throughout SZ and SM and on the surface of the parasites. After the SZ invasion DF-1 cells, it was also observed on the parasitophorous vacuole membrane. Our secretion experiments found that EtENO2 could be secreted outside the SZ. This study indicated that EtENO2 might be related to the interaction between E. tenella and host cells and be involved in the development of E. tenella resistance to some anticoccidial drugs.

Detection of quorum sensing virulence factor genes and its consanguinity to antibiotic sensitivity profile in the clinical isolates of Pseudomonas aeruginosa

Objectives

Virulent strains of Pseudomonas aeruginosa exhibit multidrug resistance by intrinsic and extrinsic mechanisms which are regulated by quorum sensing signalling systems. This includes the production of auto-inducers and their transcriptional activators to activate various virulence factors resulting in host infections. The present study is thus aimed to detect the virulence factor production, quorum sensing activity, and susceptibility pattern of P. aeruginosa to antibiotics from clinical specimens.

Materials and Methods

A total of 122 isolates of P. aeruginosa were phenotypically characterized by standard protocols and were categorized into MDR and non-MDR based on the antibiotic susceptibility profiles. Pyocyanin, alkaline protease and elastase production were assessed by qualitative and quantitative methods. Crystal violet assay was carried out for the quantification of biofilms. The genetic determinants of virulence were detected by PCR.

Results

Out of the 122 isolates, 80.3% of isolates were MDR and the production of virulence factors was in positive correlation with the presence of genetic determinants and 19.6% were non-MDR, but still showed the production of virulence factors, as confirmed by both phenotypic and genotypic methods. Few carbapenem-resistant strains were detected which did not show the production of virulence factors by both methods.

Conclusion

The study concludes, though the strains were non-MDR, they were still capable of producing the virulence factors which may be responsible for the dissemination and chronicity of the infection caused by P. aeruginosa.

Molecular characterization and analysis of the ATPase ASNA1 homolog gene of Eimeria tenella in a drug sensitive strain and drug resistant strains

The widespread use of drugs has exacerbated the resistance of Eimeria tenalla to anti-coccidial drugs. Using RNA-seq, we previously found the ATPase ASNA1 homolog of E. tenella (EtASNA1) was differentially expressed in resistant strains and drug sensitive (DS) strain. In our study, we used western blotting and quantitative real-time PCR (qRT-PCR) to analyze the translational and transcriptional levels of EtASNA1 in a diclazuril-resistant (DZR) strain, maduramicin-resistant (MRR) strain, salinomycin-resistant (SMR) strain, and DS strain and found EtASNA1 was highly expressed in three drug-resistant strains. The qRT-PCR and western blotting results also showed that the expression levels of EtASNA1 increased with increasing drug concentration, and the transcription levels of the DZR strains isolated from the field were higher than those of the DS strain. In addition, we used in vivo and in vitro tests to analyze the changes of EtASNA1 expression after DZR, MRR, and DS strain infections in chickens, and in vitro inoculation of DF-1 cells in the presence of drugs. The addition of drugs caused expression to be upregulated. The results of qRT-PCR and western blotting also showed that the expression levels of EtASNA1 in second-generation merozoites (SM) and unsporulated oocysts (UO) were significantly higher than those in the other two developmental stages. The immunofluorescence localization of EtASNA1 indicated that the protein was distributed throughout the sporozoites (SZ) and SM, except for the refractile bodies of SZ. In vitro inhibition experiments showed that anti-EtASNA1 antibody incubation significantly inhibited SZ invasion of DF-1 cells. The above results showed that EtASNA1 may be related to host cell invasion of E. tenella and may be involved in the development of E. tenella resistance to some drugs.

Positive Effect of Helicobacter pylori Treatment on Outcome of Patients With Chronic Spontaneous Urticaria

OBJECTIVES

The association between Helicobacter pylori and chronic spontaneous urticaria (CSU) is controversial. Therefore, we aimed to directly diagnose H pylori by polymerase chain reaction (PCR) in gastric tissue from patients with CSU and to investigate the association between H pylori eradication therapy and CSU remission.

METHODS

Twenty-seven of 72 patients with CSU who were positive for H pylori stool antigen and PCR in gastric biopsy specimens were randomized to receive either anti-H pylori treatment or placebo.

RESULTS

Patients with H pylori were found to have significantly lower hemoglobin concentrations with microcytic hypochromic anemia and a significantly higher occurrence of dyspepsia symptoms. All H pylori-treated patients (except two) showed significant improvement of the urticaria itching and red wheals after 2 weeks of therapy compared with the placebo group (P < .001). The response rate to treatment was 85.7% (12 patients; 95% confidence interval, 64.3%-100.0%). The two patients who failed to eradicate H pylori had an H pylori strain resistant to amoxicillin.

CONCLUSIONS

An association was observed between CSU and presence of H pylori infection in the gastric tissue. Whether this is a causal relationship or not remains to be discovered, but treatment of H pylori can significantly improve the symptoms of CSU.

Molecular epidemiological study of multidrug-resistant tuberculosis isolated from sputum samples in Eastern Cape, South Africa

Drug-resistant tuberculosis prevalence is still a global challenge. Making it imperative to examine the molecular epidemiology of drug resistant tuberculosis. Molecular epidemiology methods can evaluate transmission patterns and risk factors, ascertain transmission cases of multidrug-resistant tuberculosis (MDR-TB) and furthermore determine transmission patterns in a human populace. This work focuses on MDR-TB isolates in distinguishing them into several species and genotyping the MDR-TB isolates, mainly for epidemiological studies using the genomic regions of difference and the spoligotyping techniques. A total of 184 deoxyribonucleic acid isolated from sputum samples that showed resistance against the two major first-line anti-tuberculosis drugs (Rifampicin and Isoniazid) were examined. The deoxyribonucleic acid samples were amplified with primers specific for each flanking region of the genomic regions of difference for the identification of different MTBC species. Isolates were further characterized into different lineages using the spoligotyping commercial kit. The M. tuberculosis species was detected in 83.7% (154/184) of the deoxyribonucleic acid isolates, followed by the M. caprae in 8.7% (16/184) and the least detected species was the M. africanum in 2.2% (4/184). Nineteen spoligotype international types (SITs) were identified in this study. The pre-existing shared types were from 94.6% (174/184) isolates with 1.1% (2/184) isolates recognized as orphans and 4.3% (8/184) isolates were not found in the SITVIT database. The predominant family (spoligotype) was the Beijing with 67.4% (124/184) strains. This study gives a general overview of drug resistant strains and the circulating strains in the Eastern Cape, South Africa and it shows that the common Mycobacteria in the province is the Beijing strain.

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-β-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-β-d-glucopyranosyl-aloesaponarin-I (5) and 3-(2´,3´,4´,6´-Tetra-O-acetyl-β-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-β-d-glucopyranosyl substituent at the C3 position of the anthraquinone might have an effect against the influenza AH1N1 virus.

Resistant/susceptible classification of respiratory tract pathogenic bacteria based on volatile organic compounds profiling

Resistance to antibiotics is an emerging and growing threat. To address this threat, attempts are being made by researchers to identify the Volatile Organic Compounds (VOCs) of bacteria. It is believed that unique combinations could be found among the VOCs produced by each microorganism. The current study aimed to identify and compare the VOCs of antibiotic-resistant and standard strains of Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Acinetobacter baumannii and Klebsiella pneumoniae. A polymer of divinylbenzene /carboxen /polydimethylsiloxane was applied for absorption of volatile compounds in headspace bacterial samples in form of a solid phase micro-extraction fiber holder. Gas chromatography-mass spectrometry technique was used for identification of volatile compounds. The analysis of the VOCs indicated that some VOCs appeared only in standard strains while others were common only among resistant strains. Exclusive VOCs to a specific strain were also detected. This study demonstrated that resistant strains of bacteria produced VOCs that were different from those of the standard strains. In addition, VOCs released by bacteria after passing the logarithmic growth phase showed no significant differences. The identification of VOCs can be a precise way to differentiate bacterial species, also it can be said that the VOCs produced by different pathogenic microorganisms can be the suitable biomarkers for their detection.

Three new platinum complexes containing fluoroquinolones and DMSO: Cytotoxicity and evaluation against drug-resistant tuberculosis

This work describes the synthesis, characterization and biological evaluation of three platinum complexes of the type [Pt(DMSO)(L)Cl]Cl, in which L represents a fluoroquinolone, namely, ciprofloxacin (cpl), ofloxacin (ofl), or sparfloxacin (spf). The new complexes were characterized by elemental analysis, high-resolution mass spectrometry (HRESIMS) and ¹H, ¹³C and ¹⁹⁵Pt NMR (nuclear magnetic resonance). The spectral data suggest that the fluoroquinolones act as bidentate ligands coordinated to Pt(II) through the nitrogen atoms of the piperazine ring. Microbiological assays against wild type Mycobacterium tuberculosis (ATCC 27294) showed that all complexes have been very potent, exhibiting antitubercular potency at concentrations <2 μM, although none of the complexes presented higher potency than established anti-TB drugs. As to the resistant strains, the complex with sparfloxacin, [Pt(DMSO)(spf)Cl]Cl exhibited the best potential against most Mycobacterium tuberculosis clinical isolates. The cytotoxicity of these compounds was also evaluated in three breast cell lines: MCF-10 (a healthy cell), MCF-7 (a hormone responsive cancer cell) and MDA-MB-231 (triple negative breast cancer cell). In both tumor cell lines, [Pt(DMSO)(spf)Cl]Cl was more active and more selective than cisplatin. Flow cytometry analysis revealed that [Pt(DMSO)(spf)Cl]Cl induced late apoptotic cell death in MDA-MB-231 cells.

Antitubercular activity of 1,2,3-triazolyl fatty acid derivatives

A collection of 1,2,3-triazoles unsaturated fatty acid mimics were efficiently synthesized by click chemistry. The 1,4-disubstituted analogs prepared covered different alkyl chain lengths and triazole positions. The compounds were subsequently tested against Mycobacterium tuberculosis, being most of them active with some of the analogs displaying activity at micromolar concentration. The most potent member of the series has the triazole moiety on the C-2 position with a carbon chain of eight or ten carbon atoms. The 1,5-isomers of the most active analog were significantly less active than the original isomer. The activity of the selected hit was assayed on several clinical MTB multi-drug resistant strains providing the same MIC.

Antiplasmodial activity of new 4-aminoquinoline derivatives against chloroquine resistant strain

Emergence and spread of multidrug resistant strains of Plasmodium falciparum has severely limited the antimalarial chemotherapeutic options. In order to overcome the obstacle, a set of new side-chain modified 4-aminoquinolines were synthesized and screened against chloroquine-sensitive (3D7) and chloroquine-resistant (K1) strains of P. falciparum. The key feature of the designed molecules is the use of methylpiperazine linked α, β(3)- and γ-amino acids to generate novel side chain modified 4-aminoquinoline analogues. Among the evaluated compounds, 20c and 30 were found more potent than CQ against K1 and displayed a four-fold and a three-fold higher activity respectively, with a good selectivity index (SI=5846 and 11,350). All synthesized compounds had resistance index between 1.06 and >14.13 as against 47.2 for chloroquine. Biophysical studies suggested that this series of compounds act on heme polymerization target.