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Background: Multidrug-resistant (MDR) Gram negative superbugs are considered among the most important causes of healthcare associated infections and these resistant isolates are usually present in association with biofilms rather than planktonic existence. Objectives: This study aimed to assess the ability of EDTA, Kojic acid, and CuONPs to inhibit the phenomenon of biofilm formation by multidrug-resistant Gram-negative superbugs. Methodology: Gram negative bacilli were isolated on suitable media and identified biochemically by vitek-2 biochemical identification system. MDR isolates were tested for biofilm formation by tissue culture plate method, biofilm-producing isolates were exposed EDTA and Kojic acid by certain concentration and to copper oxide nanoparticle (CuONPs) by multiple gradual concentrations and re-tested for biofilm-production by the same method. Results: EDTA and Kojic acid reduced the biofilm-formation ability of the tested isolates by 85.4 % and 65.5% respectively with reduced mean optical density (OD) reading to (0.0267± 0.051) and (0.063± 0.108) respectively with a high statistically significant difference (p<0.0001). A concentrationdependent biofilm-inhibition effect was observed with different concentrations of CuO NPs (125-2000 µg/ml) for all the tested isolates regardless the genus and the species. Conclusion: there was a remarkable biofilm-inhibition effect for the three tested non-antibiotic substances; the use of these substances can provide a solution for the problem of difficulty in treatment of nosocomial infections due to MDR biofilm-forming Gram-negative superbugs.

Emerging pathogens known as multidrug-resistant (MDR) bacteria have resistance characteristics that have a major negative impact on human health. The emergence of microbes resistant to currently available medications has been influenced by the misuse of antibiotics. A number of methods, such as the change of antibiotics, the alteration of target sites, and the production of biofilms, are used by pathogenic bacteria to build resistance. Healthcare professionals are very concerned about bacterial colonization on surfaces in the form of biofilms because it can lead to chronic infections. It is currently urgently needed in both medicine and industry to create novel defenses against the growth of biofilms and planktonic infections, particularly strains that are resistant to antibiotics. The use of nanoparticles could be a potential solution in case of ineffectiveness of conventional methods for eliminating biofilms and the rising issue of antibiotic resistance. Metal oxide nanoparticles, like copper oxide, are among the many nanoparticles (NPs) that have attracted the greatest attention and promise. Existing biofilms are encouraged to be destroyed by copper oxide nanoparticles, which also inhibit formation of new ones. The primary cause is the toxicity of copper ions for plankton and biofilm cells. Many metal oxide nanoparticles have shown biological characteristics that are significantly more favorable than those of the parent metals NPs. For this reason, the metal oxide NPs sparked the most interest from scientific community.

Background: MRSA strains are now resistant many antibiotic groups, such as tetracyclines, aminoglycosides, and lincosamides, and become difficult to treat. Aminoglycosides are valuable antibiotics used for treatment of a variety of staphylococcal infections. Objectives: The aim of this study is to detect aminoglycoside resistance in various hospital acquired and community MRSA strain and to identify the genetic basis of this resistance. Methodology: MRSA strains were isolated and identified manually and VITEK 2 system, antibiotic susceptibility of the isolates was tested by VITEK 2 system and the MIC of various aminoglycosides was measured by E test. Conventional PCR was used to detect the genes responsible for aminoglycoside resistance among the isolates. Results: (33.3%) of CA- MRSA isolates were resistant to Amikacin, (20.8%) to Kanamicin and (37.5%) to Gentamicin, while (65.8%) of HAMRSA strains were resistant to Amikacin, (73.7%) to Kanamycin and (71.1%) to Gentamicin. the aac (6’)-Ie/aph (2”) gene was found in 58.3 % of the strains of CAIs and in 68.4% of the strains of HAIs. There is no significant difference between HAIs and CAIs harboring aac (6’)-Ie/aph (2”) gene (p value 0.419). While aph (3)-IIIa gene was found in 45.8% of the strains of CAIs and in 44.7% of the strains of HAIs. Conclusion: There was a non-significant difference between HAIs and CAIs harboring aph (3)-IIIa gene (p value 0.933). It is important to control development of aminoglycosideresistance in MRSA strains and to monitor the potential developing of new aminoglycoside resistant genes.