Biodegradation of 17 ß-estradiol by Serratia marcescens and Stenotrophomonas tumulicola co-culture isolated from a sewage treatment plant in Upper Egypt.

Background and Objectives: 17 ß-estradiol (E2) is an important pollutant of the aquatic system. It is responsible for sexual disruptions in the majority of aquatic organisms. This study aimed to search for bacteria with high potential degradation of E2 as an important method for bioremediation. Materials and Methods: Sewage water samples were collected and treated to isolate bacterial strains which were identified by conventional methods and 16S ribosomal RNA gene sequence analysis. The biodegradation of E2 by the isolated strains was evaluated under different environmental conditions. Results: Two bacterial strains were recovered from sewage water samples and identified as Stenotrophomonas tumulicola and Serratia marcescens, (named ASc2 and ASc5 respectively). Co-culture of the two strains showed biodegradation of approximately 93.6 % of E2 (50 mg. L-1) within 48 hours. However, the biodegradation capacity of the same E2 concentration was 69.4% and 71.2% for ASc2 and ASc5 each alone, respectively. The optimum cultivation conditions for efficient E2 biodegradation by co-culture were 5% (v/v) inoculation volume with 50 mg. L-1 of E2 as the initial concentration at pH 7 and 30°C within 48 hours inoculation period. Conclusion: This study detected new bacterial strains that are capable of rapid degradation of estrogen as an environmental pollutant.

New potent ciprofloxacin-uracil conjugates as DNA gyrase and topoisomerase IV inhibitors against methicillin-resistant Staphylococcus aureus.

A series of ciprofloxacin-uracil conjugates 5a-t were synthesized and identified by 1H NMR, 13C NMR, mass spectroscopy and elemental analyses. The antibacterial results revealed that the new derivatives exhibited better activity against Gram-positive than the Gram-negative strains; most of the target compounds exhibited good activities against S. aureus ATCC 6538. Compounds 5b and 5g possess the highest activities with MICs of 1.25 and 2.37 µM, respectively, which are more potent than the parent drug ciprofloxacin, MIC, 7.58 µM. In addition, they also exhibited potent activities against MRSA AUMC 261 with MICs, 0.031 and 0.046 µM respectively, higher than ciprofloxacin with MIC, 0.57 µM. Moreover, compounds 5b and 5g showed potent inhibitory activities against DNA gyrase (IC50 = 1.72 and 5.72 µM) and topoisomerase IV (4.36 and 7.77 µM) compared to ciprofloxacin with IC50 values 0.66 and 8.16 µM, respectively. The molecular docking study revealed that compounds 5b and 5g may formed stable interaction with the active sites of DNA gyrase and topoisomerase IV similar to ciprofloxacin. Hence, 5b and 5g are considered promising antibacterial candidated against MRSA AUMC 261 strains that requires further optimization.

An innovative dual recognition aptasensor for specific detection of Staphylococcus aureus based on Au/Fe3O4 binary hybrid.

Pathogenic bacteria cause disease outbreaks and threaten human health, prompting the research on advanced detection assays. Herein, we developed a selective molecular imprinted aptasensor for sensitive and prompt quantitation of Staphylococcus aureus (S. aureus) bacteria. The aptasensor was constructed by immobilization of aptamer on gold nanoparticles modified magnetic nanoparticles (apt-AuNPs@ Fe3O4). A functional monomer (o-phenylenediamine, o-phen) was electro-polymerized on the surface of the as-synthesized nanocomposite in the presence of a template (S. aureus). After removing S. aureus, the formed imprinted sites were available to extract pathogenic bacteria from complicated matrices. The surface morphology of the as-fabricated nanocomposites was characterized using different spectroscopic and electrochemical methods. Moreover, we thoroughly evaluated factors affecting the synthesis and determination procedures. The molecular imprinted aptasensor exhibited a wide linear range of 101-107 CFU mL-1 with a Limit of Detection, LOD (signal to noise = 3) of 1 CFU mL-1. The aptasensor detected S. aureus in milk, conduit water, and apple juice samples with good recoveries % and satisfactory relative standard deviations (RSDs %) values.

Prevalence of some virulence factors and genotyping of hospital-acquired uropathogenic Escherichia coli isolates recovered from cancer patients.

OBJECTIVES: This study aimed to determine the prevalence of virulence factors among uropathogenic Escherichia coli (UPEC) isolates from cancer patients and to investigate their genetic diversity using ERIC-PCR. METHODS: A total of 42 E. coli were recovered from urine samples from cancer patients admitted to Assiut University Hospital. PCR was used to detect the presence of three virulence genes (papC, iutA and cnf1). Genetic diversity of the isolates was determined using the ERIC-PCR fingerprinting method, and amplified products were separated by agarose gel electrophoresis. Gel electrophoresis banding patterns were used for dendrogram generation using NTSYSpc software. RESULTS: Among the 42 UPEC isolates, papC was the most common virulence gene (55% of isolates), followed by iutA (38%) and cnf1 (2%). ERIC-PCR successfully produced multiple amplicons (range 2-11 bands) in each strain, with molecular weights ranging from 285 to 3000 bp. Some UPEC isolates had identical ERIC-PCR profiles (identical banding patterns), whilst 22 UPEC isolates had different ERIC-PCR profiles. The phylogenetic dendrogram of ERIC-PCR showed that the 42 isolates can be differentiated into three major clusters (I, II and III), with cluster I representing 76% of isolates, cluster II representing 19% and cluster III representing 5%. CONCLUSIONS: The results of this study suggest that both papC and iutA genes may have an important role in the pathogenesis of overt urinary tract infection. Dendrogram analysis of the ERIC-PCR profiles revealed that all UPEC isolates were assigned into three main clusters, indicating the spread of distinct clonal groups that are responsible for hospital-acquired infections.

Multiple Drug Resistance Patterns in Various Phylogenetic Groups of Hospital-Acquired Uropathogenic E. coli Isolated from Cancer Patients.

Cancer patients are more susceptible to several bacterial infections, particularly urinary tract infections caused by uropathogenic E. coli (UPEC). The objective of this work was detection and the phylogenetic characterization of hospital-acquired isolates of uropathogenic E. coli in cancer patients and the determination of its relation with antibiotic resistance. A total of 110 uropathogenic E. coli responsible for hospital-acquired urinary tract infections in cancer patients were included in this study. A triplex PCR was employed to segregate different isolates into four different phylogenetic groups (A, B1, B2 and D). Drug resistance was evaluated by the disc diffusion method. All of the isolates were multiple drug-resistant (MDR) and 38.18% of all UPEC isolates were extended-spectrum beta-lactamase (ESBL) producers from which 52% were positive for the blaCTX-M gene, 40% for the blaTEM gene, and 17% for the blaSHVgene. Among 42 ESBL-producing uropathogenic E. coli isolates, the majority belonged to phylogenetic group B2 (43%), followed by group D (36%), group A (19%) and group B1 (2%). Our results have shown the emergence of MDR isolates among uropathogenic E. coli with the dominance of phylogenetic group B2. Groups A and B1 were relatively less common. The most effective drug in all phylogenetic groups was imipenem.

The Inc FII Plasmid and its Contribution in the Transmission of blaNDM-1 and blaKPC-2 in Klebsiella pneumoniae in Egypt.

The emergence of blaKPC-2 and blaNDM-1 producing Klebsiella pneumoniae represents a great problem in many Egyptian hospitals. One hundred and twenty-six K. pneumoniae isolates from patients admitted to Assiut University Hospital were identified by an API20E kit. Carbapenemase-producing K. pneumoniae (CPKP) was detected by the modified carbapenem inactivation method (mCIM), the EDTA-modified carbapenem inactivation method (eCIM), and an E-test. Based on the polymerase chain reaction, all isolates were negative for bla-VIM-1 and bla-IMP-1, fifteen of these isolates were positive for both blaKPC-2 and blaNDM-1, two isolates were positive for blaKPC-2 only, and twenty-eight isolates were positive for bla-NDM-1 only. Although one isolate was positive for the string test, all CPKP isolates were negative for capsular genes. Only 71.1% of CPKP transferred their plasmids to their corresponding transconjugants (E. coli J53). The resistance patterns of the clinical isolates and their transconjugates were similar, except for 12 isolates, which showed differences with their transconjugates in the resistance profile of four antibiotics. Molecular typing of the plasmids based on replicon typing showed that Inc FIIK and FII plasmids predominated in isolates and their transconjugants carrying blaKPC-2 and/or blaNDM-1. Conjugative Inc FII plasmids play an important role in the spread of CPKP, and their recognition is essential to limit their spread.