Migratory birds as the vehicle of transmission of multi drug resistant extended spectrum β lactamase producing Escherichia fergusonii,an emerging zoonotic pathogen

The acquisition of multi-drug resistance (MDR) genes by pathogenic bacterial bugs and their dispersal to different food webs has become a silent pandemic. The multiplied use of different antibacterial therapeutics during COVID-19 pandemic has accelerated the process among emerging pathogens. Wild migratory birds play an important role in the spread of MDR pathogens and MDR gene flow due to the consumption of contaminated food and water. Escherichia fergusonii is an emerging pathogen of family Enterobacteriaceae and commonly causes disease in human and animals. The present study focused on the isolation of E. fergusonii from blood, saliva, and intestine of selected migratory birds of the Hazara Division. The sensitivity of isolated strains was assessed against ten different antibiotics. The isolation frequency of E. fergusonii was 69%. In blood samples, a high rate of resistance was observed against ceftriaxone (80%) followed by ampicillin (76%) whereas, in oral and intestinal samples, ceftriaxone resistant strains were 56% and 57% while ampicillin resistance was 49% and 52% respectively. The overall ceftriaxone and ampicillin-resistant cases in all three sample sources were 71% and 65% respectively. In comparison to oral and intestinal samples, high numbers of ceftriaxone-resistant strains were isolated from the blood of mallard while ampicillin-resistant strains were observed in blood samples of cattle egrets. 16S rRNA-based confirmed strains of E. fergusonii were processed for detection of CTX-M and TEM-1 gene through Polymerase chain reaction (PCR) after DNA extraction. Hundred percent ceftriaxone resistant isolates possessed CTX-M and all ampicillin-resistant strains harbored TEM-1 genes. Amplified products were sequenced by using the Sanger sequencing method and the resulted sequences were checked for similarity in the nucleotide Database through the BLAST program. TEM-1 gene showed 99% and the CTX-M gene showed 98% similar sequences in the Database. The 16S rRNA sequence and nucleotide sequences for TEM-1 and CTX-M genes were submitted to Gene Bank with accession numbers LC521304, LC521306, LC521307 respectively. We posit to combat MDR gene flow among the bacterial pathogens across different geographical locations, regular surveillance of new zoonotic pathogens must be conducted.     

Specific Antimicrobial Synergism of Synthetic Hydroxy Isothiocyanates with Aminoglycoside Antibiotics

Hydroxy isothiocyanates, especially 2-(4-hydroxy-phenyl)ethyl isothiocyanate (hITC), were examined for antimicrobial synergism with several antibiotics against Escherichia coli and Staphylococcus aureus, using a multiwell plate system. hITC had antibacterial synergism, specifically with aminoglycoside antibiotics. The synergism was observed in synthetic medium (M9 minimal medium) or soybean casein digest broth, but not in nutrient broth. Synergism was seen in the presence of certain sugars such as glucose, fructose, and maltose in the medium.     

Effects of Chemical Products on Fire Blight Suppression,and Fruit Production and Quality in Apple (<i>Malus domestica</i> Borkh.) cv. Golden Glory

Antibiotics are widely used in fire blight management programs, yet there are no studies that demonstrate the evaluation of their efficacy in Mexico. Therefore, the present study was conducted to investigate the effects of the active ingredients in five commercial products (Kasumin^® 2L, Agrygent Plus^®, Agricultural Terramycin^®, Agrimicin^® 100, and Actigard^®) on fire blight suppression, and fruit yield and quality of apple (Malus domestica Borkh.) cv. Golden Glory. The experiment was conducted in a commercial orchard using a completely randomized block design, with six treatments: (1) Oxytetracycline [Ox], 110 mg L⁻¹; (2) Kasugamycin [Kas], 4.7 mL L⁻¹; (3) Oxytetracycline + Gentamicin [Ox + Gen], 48 mg L⁻¹+12 mg L⁻¹; (4) Streptomycin + Oxytetracycline [Str + Ox], 90 mg L⁻¹+9 mg L⁻¹; (5) Acibenzolar-S-methyl [ASM], 70 mg L⁻¹; and (6) Control, only water, with four replications, and three 11-year-old trees as an experimental unit. Variables of infection including flowers, shoots and fruits, yield and fruit quality were evaluated. All treatments suppressed infection in flowers, shoots, and fruits. ASM provided the highest levels of reduction of flower and shoot infection, while Kas had the least effect on the reduction of infection in these variables. The Ox + Gen treatment had the greatest suppression of fruit infection, and the best results on fruit yield and quality, followed by Ox and ASM. This is the first study conducted to evaluate the efficacy of the active ingredients of five commercial products used for the management of fire blight in apple trees in Mexico.     

Sulfonamide phenylalanine (SPA) series of analogues as an antibacterial,antifungal, anticancer agents along with p53 tumor suppressor-DNA complex inhibitor – part 1

Abstract

A series of N-[1-benzyl-2-oxo-2-substituted(ethyl)] benzene/p-toluene sulfonamide (K1–K12) are synthesized. Structure of the synthesized analogues has been confirmed by FT-IR, ¹H & ¹³C NMR and ESI-MS spectroscopic techniques. All the synthesized analogues (K1–K12) have also been examined for their in-vitro antibacterial and antifungal activities. Compounds showed good antibacterial and antifungal activity against standard drug. Anticancer study has been carried out on three cancer cell lines PC-3, MCF-7 and A549 on two different concentrations (mg/mL and μg/mL). The K4 sulfonamide analogue showed better anticancer activity amongst all analogues against PC-3 and A549 cell lines. K4 inhibit G0/G1 phase in cell-cycle analysis experiment. All synthesized molecules (K1–K12) dock at junction p53-DNA and make hydrogen bonded with residues of p53 protein as per docking study. ADMET predictions of synthesized phenylalanine sulfonamide analogues (K1–K12) has been done using ‘Lipinski rule’ and it has been observed that all synthesized analogues did not violate the rule. Electronic, chemical properties and mulliken atomic charges of analogues were calculated using density functional theory (DFT).

Communicated by Ramaswamy H. Sarma     

链霉素抗性突变--纳他霉素高产菌株的选育研究

应用链霉素抗性筛选法,将经过紫外线诱变处理的纳他霉素生产菌——褐黄孢链霉菌(Streptomyces gilvosporeus)ATC13326的孢子涂布在含有链霉素最小抑制浓度(0．6μg／mL)的培养基平板上,获得了122株链霉素抗性突变株。其中纳他霉素产量高于出发菌株的有13株,产量阳性效率达到10．6％,同时获得了产抗生素能力为出发菌株1．46倍的突变株SG-56。     

Targeting Brucella melitensis with polymeric nanoparticles containing streptomycin and doxycycline

Treatment and eradication of intracellular pathogens such as Brucella is difficult because infections are localized within phagocytic cells and most antibiotics, although highly active in vitro , do not actively pass through cellular membranes. Thus, an optimum strategy to treat these infections should address targeting of active drugs to the intracellular compartment where the bacteria replicate, and should prolong the release of the antibiotics so that the number of doses and associated toxicity can be reduced. We incorporated streptomycin and doxycycline into macromolecular nanoplexes with anionic homo- and block copolymers via cooperative electrostatic interactions among the cationic drugs and anionic polymers. The approach enabled simultaneous binding of both antibiotics into the nanoplexes, and their use resulted in an improvement in performance as compared with the free drugs. Administration of two doses of the nanoplexes significantly reduced the Brucella melitensis load in the spleens and livers of infected BALB/c mice. The nanoplexes were more effective than free drugs in the spleens (0.72-log and 0.51-log reductions, respectively) and in the livers (0.79-log and 0.42-log reductions, respectively) of the infected mice. Further research regarding the design of optimum nanoplex structures will be directed towards alterations in both the core and the shell properties to investigate the effects of the rates and pathways of entry into immune cells where the brucellae replicate.     

An improved procedure for protoplast microelectrofusion and culture of Nicotiana tabacum intraspecific somatic hybrids: plant regeneration and initial proofs on organelle segregation

Somatic hybrids were produced between haploid Nicotiana tabacum L. cv. Petite Havana (wild type) and haploid streptomycin resistant (SR1) mutant by an improved version of microelectrofusion of preselected pairs of protoplasts and the culture of fusion products in a nurse culture. Resistance of diploid plants regenerated from 20 somatic hybrid clones was tested at low concentration of streptomycin in the light as well as at high concentrations of streptomycin in the dark. In two independent hybrid lines, plants resistant in the light but sensitive in the dark were found. The existence of this plant type indicates a segregation of chloroplasts and mitocondria in somatic hybrid clones. It is suggested that microelectrofusion of preselected pairs of protoplasts combined with a reliable nurse culture might be a good technique for controlled somatic hybridization, cell reconstitution and partial gene transfer to different plant species. It might also be used to follow and analyse organelle segregation in somatic hybrid clones. The possibility that mitochondria might be resistant to streptomycin in the SR1 mutant is also discussed.     

链霉素对鸟听觉毒性作用的研究

目的：了解链霉素对鸟听觉毒性的作用。方法：选33只健康成年虎皮鹦鹉,不同剂量的链霉素肌肉注射15日,脑干听觉诱发电位测试外周的听觉敏度和听觉通路中神经的传导和传递能力。结果：链霉素对鸟听觉有毒性作用。结论：用链霉素处理鸟可以制作聋鸟模型。     

Biochemical studies with bi-resistant mutants (ethambutol plus streptomycin and isoniazid plus streptomycin) ofMycobacterium smegmatis ATCC 607

Biochemical characteristics of bi-resistant mutants (resistant to ethambutol plus streptomycin or isoniazid plus streptomycin) of mycobacteria isolated by replica plating fromMycobacterium smegmatis ATCC were compared with those of the drug-susceptible strains. Reduced incorporation of [¹⁴C]uracil, [³H]lysine and [¹⁴C]acetate into RNA, protein and phospholipids respectively was seen in the resistant mutants. Total phosphorlipids were enhanced in ethambutol plus streptomycin resistant mutant and decreased in isoniazid plus streptomycin resistant mutant. There were similar changes in levels of individual phospholipids. The resistant mutants revealed an accumulation of phospholipids in the cell wall, and a marked decrease of phospholipids in the cell membrane in comparison to the susceptible strain. Several qualitative alterations in the polypeptide profile (with respect to number and molecular weight) of the crude protein extract and of different subcellular compartments were seen in the resistant mutants.     

Prophage lambda at unusual chromosomal locations. II. Mutations induced by bacteriophage lambda in Escherichia coli K12

An Escherichia coli strain deleted for the primary λ attachment site was lysogenized with λ at secondary sites. Some lysogens became mutants because of prophage insertion in the affected gene. Mutagenesis by phage λ is not random with respect to the gene affected: most mutants were pro, although certain other genes could be mutated at lower frequencies. In the case of several independent ilv and gal mutants, the sites of prophage insertion were in the same segment of the ilv region and galT gene respectively. The galT location may also be a preferred site for the insertion of DNAs other than prophage λ. Insertion of prophage λ within an operon can reduce the expression of operator-distal genes. A trpC λ insertion mutant expresses the operator-distal trpB function constitutively at a low level. This expression probably derives from a promoter located in the left arm of the prophage.