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Background: Pseudomonas aeruginosa is one of the most important causes of nosocomial infections that easily gains resistance to many antibiotics. This opportunistic pathogen is a major health hazard particularly in immunocompromised patients and patients with surgical wound infection. P. aeruginosa may be originated from different sources and comprises a high colonization and transmission capacity. The aim of this study is to determine the antimicrobial susceptibility pattern of the P. aeruginosa isolates and to investigate the potential sources of infection in surgical site infected patients by genotyping using RAPD-PCR. Methodology: samples were taken from patients (217), health staff (30), environment (88) and antiseptics and hand washing solutions (60). After isolation and identification of P. aeruginosa, antimicrobial susceptibility testing was performed using disc diffusion method. DNA was extracted from the isolates and RAPD-PCR method was applied to the DNA extract using a short single primer of 272. The technique created repetitive electrophoresis patterns which was used for genotypic differentiation. Results: 24.8% of patient samples were positive for P. aeruginosa and 10% of staff hand samples were positive. The highest frequency of pseudomonas isolation from environmental samples was from mops (55.6%) followed by door handles (44.4%) and sinks (40%). The RAPD typing method gave higher discriminatory index (0.807) than antibiogram (0.617). Epidemiological linkages were proven by analyzing antibiogram and RAPD-PCR typing data. Conclusion: hand hygiene, environmental cleaning and disinfection of patient objects to reduce environmental reservoirs of P. aeruginosa. It is better to limit the usage of antibiotics in the hospitals as ceftolozane-tazobactam and ceftazidime-avibactam to be used only when absolutely needed. RAPD molecular typing method was superior to antibiotic typing and should be used in tracing the source of infection. [ABSTRACT FROM AUTHOR]

Background: The growing incidence of multidrug resistant (MDR) bacterial infections has become a public health crisis. This work aims to evaluate the in-vitro activity of silver nanoparticles (AgNPs), alone and in combination with the antimicrobials amikacin and ceftazidime, against MDR Gram-negative bacilli (GNB) isolated from clinical cases in Zagazig University Hospitals. Methods: In a cross sectional study, MDR GNB were isolated from different clinical specimens and were tested to determine the minimal inhibitory concentration (MIC), minimal bactericidal concentration (MBC) and bactericidal activity of AgNPs using broth microdilution method. The effect of combining subMIC levels of AgNPs (MIC/2 and MIC/4) with amikacin and ceftazidime, was also determined by broth microdilution. Results: A total of 63 MDR GNB was obtained during the study period (22 E. coli, 17 Klebsiella, 15 Pseudomonas aeruginosa and 9 Acinetobacter isolates). AgNPs demonstrated a bactericidal effect on all tested isolates with an MBC/MIC ratio of less than 4. When combined with amikacin, a synergistic effect was demonstrated on all tested E.coli and Klebsiella isolates at AgNPs MIC/2 and on 45.4%, 40% and 77.8% of E.coli, P.aeruginosa and Acinetobacter isolates, respectively at MIC/4. In combination with ceftazidime, AgNPs exhibited a synergistic effect on 100% of E. coli and 88.2% Klebsiella at both MIC/2 and MIC/4 and on 40% of P. aeruginosa isolates at AgNPs MIC/4. Conclusions: AgNPs exert a bactericidal activity on MDR GNB as well as a synergistic effect when combined with amikacin and ceftazidime suggesting them as a new weapon in the war against MDR GNB. [ABSTRACT FROM AUTHOR]

Fecal contamination of drinking water is a major health problem which accounts for many cases of diarrhea mainly in infants and foreigners. This contamination is a complex interaction of many parameters. Antibiotic resistance among bacterial isolates complicates the problem. The study was done to identify fecal contamination of drinking water by Diarrheagenic Antibiotic-Resistant Escherichia coli in Zagazig city and to trace reasons for such contamination, three hundred potable water samples were investigated for E. coli existence. Locations of E. coli positive samples were investigated in relation to population density, water source, and type of water pipe. Sixteen E. coli strains were isolated. Antibiotic sensitivity was done and enterotoxigenic, enteropathogenic, and enterohaemorrhagic virulence genes were investigated by PCR. Probability of fecal contamination correlated with higher population density, with increased distance from Zagazig water plant, and with asbestos cement water pipes. Resistance to at least one antimicrobial drug was found in all isolates. Virulence genes were detected in a rate of 26.27%, 13.13%, 20%, 6.67%, and 33.33% for LT, ST, stx1, stx2, and eae genes, respectively. This relatively high frequency of fecal contamination points towards the high risk of developing diarrhea by antibiotic resistant DEC in low socioeconomic communities particularly with old fashion distribution systems. [ABSTRACT FROM AUTHOR]