Dina Ezzat - Academia.edu (original) (raw)

Papers by Dina Ezzat

Research paper thumbnail of Changes in Outer Membrane Proteins of Benzalkonium Chloride Adapted Pseudomonas Aeruginosa and Mutations in GyrA and ParC Genes

Medical Journal of Cairo University, 2019

Background: Benzalkonium Chloride (BC) is widely used in hospitals, industry and cosmetics. Adapt... more Background: Benzalkonium Chloride (BC) is widely used in hospitals, industry and cosmetics. Adaptation of Pseu-domonas aeruginosa to BC was increased. This adaptation may lead to the emergence of cross-resistance to other disinfectants and antibiotics. Little attention has been focused on the resistant mechanisms.

Research paper thumbnail of Efficacy Of Combination Of Glutaraldehyde And Benzalkonium Chloride Against Multidrug-Resistant Gram Negative Bacteria Isolated From Hospitals.

Journal of Applied Sciences Research, 2012

Due to the growing number of outbreaks of nosocomial infections in hospitals, it has been shown ... more Due to the growing number of outbreaks of nosocomial infections in hospitals, it has been shown that the appropriate environmental hygienic and disinfection practices can be very helpful to hospital infection control. The aim of this study was to evaluate the efficacy of glutaraldehyde and benzalkonium chloride alone and in combination against antibiotic-resistant hospital Gram-negative bacteria (GNB) isolated. Twenty one isolates of antibiotic-resistance GNB (11 strains of Escherichia coli, 5 strains of Salmonella typhi, 3 strains of klebsiella pneumoniae and 2 strains of Pseudomonas aeruginosa) were selected from seventy one GNB which had been collected of some clinical hospitals in Cairo, Egypt. These were evaluated to determine the minimal inhibitory concentration (MIC) values of Glutaraldehyde and Benzalkonium Chloride, separately and in combinations. In addition, to choice one isolate from each strain. MIC for both agents alone or in combination was recorded. Whereas, MIC results of glutaraldehyde was 3000 mg/L for E.coli, K. pneumoniae, P. aeruginosa and S. typhi, and MIC results of benzalkonium chloride was 256 mg/L for K. pneumoniae and S. typhi and also was 64 mg/L and 128 mg/L for E. coli and P. aeruginosa, respectively. In addition, the microbicidal effect was determined by using quantitative suspension tests log10 reductions of test bacteria after contact times 15 sec., 1 and 5 minutes. The best log10 reductions of glutaraldehyde was concentration 2000 mg/L for K. pneumoniae after 1 & 5 minutes, While, it was 3000 mg/L against E. coli, S. typhi and P. aeruginosa after 1 & 5 minutes. The log10 reductions of benzalkonium chloride was concentration 256 mg/L for K. pneumoniae after one minute, E. coli at concentration 512 mg/L after contact 15 second and against, S. typhi after 5 minutes at concentration 128 mg/L. and The preferred log10 reductions of combinations was 2000 mg/L of glutaraldehyde plus 8 mg/L of benzalkonium chloride after contact five minutes against E. coli and S. typhi, after one minute against K. pneumoniae and 15 second contact for P. aeruginosa.

Research paper thumbnail of Correlation between resistance of Pseudomonas aeruginosa to benzalkonium chloride and expression of efflux pump genes ARTICLE INFO

Study of cross-resistance to other antimicrobial agents and efflux pump (EP) resistance mechanism... more Study of cross-resistance to other antimicrobial agents and efflux pump (EP) resistance mechanism in benzalkonium chloride (BC) adapted Pseudomonas aeruginosa isolates. Minimum inhibitory concentration (MIC) of BC of 88 P. aeruginosa isolates that collected from clinical settings in Egypt and cross-resistance of BC-adapted isolates to other antimicrobial agents were determined by agar dilution method. EP regulatory genes (i.e., MexR, NfxB, MexT, and MexZ) were detected by PCR in BC adapted isolates, and then EP activity of isolates which have these four genes was determined by cartwheel method followed by sequencing for the isolate which showed the highest EP activity. Finally; the expression of EP genes (MexA, MexC, MexE, and MexX) was determined in the same isolate by realtime polymerase chain reaction (RT-PCR) in presence and absence of the most potent efflux pump inhibitor (EPI). Twenty isolates were BC-adapted with MIC 2,048 mg/l, showed cross-resistance to cetrimide and ciprofloxacin but not to other disinfectants used. The isolate no. 87 selected to be sequenced. Mutation founded in MexR (V126E) and MexZ (L138R) genes. By RT-PCR, sertraline (the most potent EPI used) decreased the expression of the EP genes to three-folds. These results demonstrate that EP was the major mechanism of resistance to BC.

Research paper thumbnail of Changes in Outer Membrane Proteins of Benzalkonium Chloride Adapted Pseudomonas Aeruginosa and Mutations in GyrA and ParC Genes

Medical Journal of Cairo University, 2019

Background: Benzalkonium Chloride (BC) is widely used in hospitals, industry and cosmetics. Adapt... more Background: Benzalkonium Chloride (BC) is widely used in hospitals, industry and cosmetics. Adaptation of Pseu-domonas aeruginosa to BC was increased. This adaptation may lead to the emergence of cross-resistance to other disinfectants and antibiotics. Little attention has been focused on the resistant mechanisms.

Research paper thumbnail of Efficacy Of Combination Of Glutaraldehyde And Benzalkonium Chloride Against Multidrug-Resistant Gram Negative Bacteria Isolated From Hospitals.

Journal of Applied Sciences Research, 2012

Due to the growing number of outbreaks of nosocomial infections in hospitals, it has been shown ... more Due to the growing number of outbreaks of nosocomial infections in hospitals, it has been shown that the appropriate environmental hygienic and disinfection practices can be very helpful to hospital infection control. The aim of this study was to evaluate the efficacy of glutaraldehyde and benzalkonium chloride alone and in combination against antibiotic-resistant hospital Gram-negative bacteria (GNB) isolated. Twenty one isolates of antibiotic-resistance GNB (11 strains of Escherichia coli, 5 strains of Salmonella typhi, 3 strains of klebsiella pneumoniae and 2 strains of Pseudomonas aeruginosa) were selected from seventy one GNB which had been collected of some clinical hospitals in Cairo, Egypt. These were evaluated to determine the minimal inhibitory concentration (MIC) values of Glutaraldehyde and Benzalkonium Chloride, separately and in combinations. In addition, to choice one isolate from each strain. MIC for both agents alone or in combination was recorded. Whereas, MIC results of glutaraldehyde was 3000 mg/L for E.coli, K. pneumoniae, P. aeruginosa and S. typhi, and MIC results of benzalkonium chloride was 256 mg/L for K. pneumoniae and S. typhi and also was 64 mg/L and 128 mg/L for E. coli and P. aeruginosa, respectively. In addition, the microbicidal effect was determined by using quantitative suspension tests log10 reductions of test bacteria after contact times 15 sec., 1 and 5 minutes. The best log10 reductions of glutaraldehyde was concentration 2000 mg/L for K. pneumoniae after 1 & 5 minutes, While, it was 3000 mg/L against E. coli, S. typhi and P. aeruginosa after 1 & 5 minutes. The log10 reductions of benzalkonium chloride was concentration 256 mg/L for K. pneumoniae after one minute, E. coli at concentration 512 mg/L after contact 15 second and against, S. typhi after 5 minutes at concentration 128 mg/L. and The preferred log10 reductions of combinations was 2000 mg/L of glutaraldehyde plus 8 mg/L of benzalkonium chloride after contact five minutes against E. coli and S. typhi, after one minute against K. pneumoniae and 15 second contact for P. aeruginosa.

Research paper thumbnail of Correlation between resistance of Pseudomonas aeruginosa to benzalkonium chloride and expression of efflux pump genes ARTICLE INFO

Study of cross-resistance to other antimicrobial agents and efflux pump (EP) resistance mechanism... more Study of cross-resistance to other antimicrobial agents and efflux pump (EP) resistance mechanism in benzalkonium chloride (BC) adapted Pseudomonas aeruginosa isolates. Minimum inhibitory concentration (MIC) of BC of 88 P. aeruginosa isolates that collected from clinical settings in Egypt and cross-resistance of BC-adapted isolates to other antimicrobial agents were determined by agar dilution method. EP regulatory genes (i.e., MexR, NfxB, MexT, and MexZ) were detected by PCR in BC adapted isolates, and then EP activity of isolates which have these four genes was determined by cartwheel method followed by sequencing for the isolate which showed the highest EP activity. Finally; the expression of EP genes (MexA, MexC, MexE, and MexX) was determined in the same isolate by realtime polymerase chain reaction (RT-PCR) in presence and absence of the most potent efflux pump inhibitor (EPI). Twenty isolates were BC-adapted with MIC 2,048 mg/l, showed cross-resistance to cetrimide and ciprofloxacin but not to other disinfectants used. The isolate no. 87 selected to be sequenced. Mutation founded in MexR (V126E) and MexZ (L138R) genes. By RT-PCR, sertraline (the most potent EPI used) decreased the expression of the EP genes to three-folds. These results demonstrate that EP was the major mechanism of resistance to BC.