BACKGROUND: Today, the fight against the bacteria causing foodborne diseases is of particular importance in the packaging of seafood. It is therefore vital to find new compounds with antibacterial properties.OBJECTIVES: In the present study, antibacterial properties of synthetic nanocomposite zinc chromite-zinc aluminate (ZnCr2O4-ZnAl2O4) on E. coli and Pseudomonas aeruginosa were studied.METHODS: After synthesis of nanocomposite, antibacterial activity of nanocomposite zinc chromite-zinc aluminate was evaluated via disk diffusion method, Minimum Inhibition Concentration (MIC), and Minimum Bactericidal Concentration (MBC) using the microdilution method.RESULTS: The results of this study revealed a higher sensitivity reaction of Pseudomonas aeruginosa (18.6±1.2 mm) compared to E. coli (12.7 ± 1.4 mm). No significant differences were observed between Gentamicin antibiotic and synthetic nanocomposite against Pseudomonas aeruginosa (P<0.05). The minimum MIC and MBC concentrations were seen in Pseudomonas aeruginosa (1.66 mg/ml) and the maximum concentration of MIC belonged to E. coli (5 mg/ml).CONCLUSIONS: In this study, the effects of nanoparticles on these gram-negative bacteria could be attributed to the small diameter of the ions, and hence the greater penetrability of these nanoparticles despite the wall's resistance. Based on the results, zinc chromite-zinc aluminate nanocomposite showed a better performance compared with gram-negative bacteria, specifically Pseudomonas aeruginosa resistant bacteria, and could be used for further studies in fisheries product packaging.

BACKGROUND: Heparin is a sulfated glycosaminoglycan. Blood is a common source for DNA detection in all kinds of samples, and anticoagulants such as heparin and ethylenediaminetetraacetic acid (EDTA) are used to prevent coagulation. Because heparin has a strong inhibitory effect on polymerase chain reaction (PCR), it is not used in samples that will be tracked by DNA. There are physical, chemical, and enzymatic methods to eliminate the inhibitory effect of heparin on PCR test.OBJECTIVES: First, to compare the intensity of the inhibitory effect of two anticoagulants, heparin, and EDTA, on the Real-Time PCR (qPCR), and then to investigate the impact of the heparinase enzyme present in the medium culture extract of Pseudomonas aeruginosa, on removing the inhibitory effect of heparin during the real-time PCR.METHODS: In the present study, two blood samples containing heparin and EDTA were subjected to a real-time PCR test to check the intensity of the inhibitory effect. Then, the medium culture extract of Pseudomonas aeruginosa was added to the heparinized blood sample infected with Escherichia coli bacteria in two groups with different conditions. In the first group, the DNA in the heparinized blood sample was extracted by the phenol-chloroform isoamyl alcohol method. Then, these samples were incubated with the extract of Pseudomonas aeruginosa bacteria culture medium at different hours, but in the second group, the samples were incubated at different hours before DNA extraction. Also, the DNA concentration in both groups was measured by a Nanodrop device, and finally, all samples were subjected to a real-time PCR test.RESULTS: The results of the research samples showed that although the heparinized blood sample contains more DNA concentration than the EDTA blood sample, it completely prevents genome replication. Also, incubating heparinized blood with Pseudomonas aeruginosa culture medium extract before DNA extraction for more than 24 hours removes the inhibitory effect of heparin during the real-time PCR, even at a lower cycle threshold than the EDTA-containing sample.CONCLUSIONS: The Pseudomonas aeruginosa culture medium extract may enable researchers to use heparinized blood samples for genome amplification and diagnosis without using expensive and limited commercial heparinase enzyme.

To analyze the major outer membrane proteins (OMPs) of the sensitive or resistant Pseudomonas aeruginosa strains, the OMPs were separated from the cellular elements by sarcosyl extraction method. OMPs profiles were conducted by SDSpolyacrylamide gel electrophoresis. Amoxicillin clavulanic acid (AMC) sensitive P.aeruginosa serotype K showed four protein bands; 35.713, 31.159, 26.107 and 22.869 KD. While AMC sensitive P. aeruginosa serotype H showed three bands of 35.713, 27.164 and 23.174 KD. Whereas AMC resistant P. aeruginosa serotype G, that was positive for the blaTEM gene by the PCR, modified its protein pattern. It has five protein bands of 52.142, 38.525, 30.690, 27.164 and 22.569 KD. These findings suggested that blaTEM gene and the outer membrane protein barrier are contributed to the resistance to amoxicillin clavulanic acid in P. aeruginosa. To determine a possible relationship between the resistance of P. aeruginosa and the production of antibodies against its outer membrane protein, antibodies against OMPs of AMC sensitive and resistant P. aeruginosa strains were prepared in mice and evaluated by ELISA. Our results showed that there was no association between immunogenicity of the outer membrane proteins and resistance of P. aeruginosa to antibiotics.

Carbapenem-resistant Pseudomonas aeruginosa (CRPA) has become the leading cause of health care-associated infections. Treatment is difficult due to the lack of an effective antimicrobial therapy, and mortality is high. This study investigated the occurrence of CRPA in farm animals (buffaloes and cattle), livestock drinking water, and humans in Egypt. A total of 180 samples were examined: 50 faecal each from buffaloes and cattle, 30 of livestock drinking water, and 50 stool from humans. The samples were cultured on cetrimide agar and the plates were incubated aerobically at 37°C for 24 h. The isolates were examined for the presence of the blaKPC, blaOXA₋₄₈, and blaNDM carbapenemase-encoding genes using PCR and investigated for the exotoxin A (toxA) gene. The toxA gene from carbapenem- group resistant isolates was phylogenetically analysed. P. aeruginosa was isolated from buffaloes, cattle, drinking water, and humans, with occurrences of 40%, 34%, 10%, and 20%, respectively. Carbapenem resistance genes were found in 60%, 59%, 67%, and 70% in buffalo, cattle, water and human samples, respectively. The toxA gene was detected in 80% of samples. The phylogenetic analysis showed that cattle and water sequences were in one cluster and more related to each other than to human isolates. Occurrence of CRPA among farm animals, drinking water, and humans was high, reflecting the environmental origin of P. aeruginosa and highlighting contaminated water as a potential transmitter of CRPA to livestock and next to humans.

The emergence of antibiotic-resistant bacteria has led to increased bacterial infections that are difficult to treat. Bacteriophage therapy presents a potential solution to this problem. In this study, three phages isolated from different water sources in Ismailia were identified as potential candidates for bacteriophage therapy to control Pseudomonas aeruginosa bacteria. The phages were characterized according to morphology, host range, physical characteristics, and genetic differences. Based on their head and tail features, TEM images were utilized to identify two phages from the Siphoviridae family and one from the Myoviridae family. The phages were also tested for their tolerance to different physical and chemical factors such as temperature, pH, salinity, chloroform, and exposure to the laser, blood plasma, and essential oils. The three phages exhibited different preferences and tolerances to these factors, suggesting that they may be effective against different bacterial strains of P. aeruginosa in different environments. The study demonstrates the potential of phage therapy as an alternative to antibiotic therapy and highlights the importance of understanding phage characteristics in developing effective phage formulations.

Pseudomonas aeruginosa (P. aeruginosa) is one of the most common causative agents causing mastitis in dairy cattle, which is primarily responsible for the dairy farms' significant economic losses. The purpose of this study was to investigate the prevalence, antimicrobial sensitivity profiling, phenotypic detection of extended-spectrum ß-lactamase (ESBL) producing isolates, molecular identification of major virulence factors (toxA, lasB, and exoS), and biofilm profiles of P. aeruginosa strains isolated from mastitis milk. A total of 200 mastitic milk samples were collected from cows and subjected to bacteriological examination. Suspected colonies were confirmed by PCR targeting the 16S rRNA gene. Positive isolates were genotypically examined to determine the presence of virulence factors (toxA, lasB, and exoS). An antimicrobial susceptibility test was carried out on all positive isolates. The phenotypic detection of ESBL was done using the combination disc test (CDT) and the double disc synergy test (DDST). Finally, biofilm production was accessed through the tube adherent method (TA). Among the total samples, P. aeruginosa was identified in 15% (n = 30) of the retrieved isolates. Virulence genes (toxA, exoS, and lasB) were detected in 100%, 83.3%, and 66.6% of isolates, respectively. Antimicrobial susceptibility testing showed high sensitivity to imipenem, meropenem, ciprofloxacin, colistin, and gentamicin, while all isolates were completely resistant to amoxicillin, penicillin, ceftazidime, ceftriaxone, streptomycin, erythromycin, doxycycline, and spectinomycin. CDT confirmed ESBL production in 15 isolates (50%) and DDST confirmed it in 10 isolates (33.3%). Biofilm formation by the TA method revealed that 33.3% were strong, 33.3% were moderate, 16.6% were weak, and 16.6% were nonadherent isolates. In conclusion, P. aeruginosa strains on dairy farms that harbor virulence genes, produce biofilm, and are resistant to the most popular antimicrobial drug can be hazardous not only to the dairy industry but also for public health.

Despite of the great efforts to develop effective control programs for mastitis, it is still one of the most economically important diseases in dairy cattle herds. Pseudomonas aeruginosa is a member of coliform Gram-negative bacteria causing treatment-resistant clinical or sub-clinical mastitis in dairy cows. This study aimed to evaluate the influence of affection with clinical P. aeruginosa mastitis on some oxidative stress biomarkers, inflammatory cytokines and proteins, in addition to some complement factors in Holstein dairy cows. Affection with P. aeruginosa mastitis evoked a state of oxidative stress which accompanied with depletion of cellular enzymatic and non-enzymatic anti-oxidants and elevation of lipid peroxide and advanced oxidation protein product (AOPP) level. Additionally, this affection stimulated the release of some inflammatory cytokines and proteins, enhanced activity of caspase-1. In contrary, the level of complement factor 2 (C2), complement fragments C3b and complement fragment C5a has been decreased upon affection with mastitis. In conclusion, marked oxidative stress state and enhanced release of inflammatory cytokines and proteins with complement system defective activation may share in pathogenesis and virulence of P. aeruginosa-induced clinical mastitis in dairy cattle.

About 8 year-old castrated male Yorkshire terrier was presented for evaluation of dysuria, stranguria, hemtauria, and pollakiuria. On history taking, dysuria first was observed three months ago and these signs were waxed and waned. Physical examination revealed mild left perineal swelling. On routine laboratory examination, no significant findings were identified. Positive contrast urogram identified peritoneal herniation of urinary bladder. Urinalysis showed proteinuria and hematuria.

Kishk is a traditional dry fermented dairy product prepared from a mixture of salted sour butter milk or yoghurt with wheat grains. Goal was to evaluate the microbiological quality, together with isolation and identification of LAB from kishk and assessed their protective effects against E. coli and Pseudomonas aeruginosa in vitro and in vivo. One hundred samples of kishk were randomly obtained from farmers’ houses and food stores in the Assuit province, Egypt. Total viable count and, total yeasts and molds were performed by plating the samples on selective media. Further, LAB were isolated on de Man Rogosa and Sharpe (MRS) agar and identified by biochemical tests. The antagonistic effect of the obtained LAB was evaluated against two of foodborne patogens (E. coli and Pseudomonas aeruginosa) in vitro using well diffusion method and in vivo after inoculation in cow’s milk. The average count of total bacterial counts and, total yeasts and molds were 8.13 ± 0.09 and 2.92 ± 0.16 log10 CFU/g, respectively. On the basis of phenotypical examination, LAB were identified and classified into three groups of LAB namely Lactobacillus, Leuconostoc and Lactococcus. Notably, LAB had more inhibitory activity against against E. coli in comparison to Pseudomonas aeruginosa in vitro. However, there was no changes in the mean count of the tested organisms versus control group after inoculation in milk. This study discovered that kishk contain LAB bacteria that have antagonistic properties on E. coli and Pseudomonas aeruginosa. Hence, kishk could be a useful candidate for the human health.

Poultry bacterial pathogen is a major problem in poultry farms, with serious consequences for poultry and human. Two hundred samples of apparently health and freshly died broiler were collected from different commercial farms at Sharkia governorate, Egypt. Salmonella spp. detected in (29%) of examined specimens and serologically identified into S. Typhimurium, S. Kentucky, S. Infantis, S. Enteritidis and S. Agama with percentages 9.5%, 6.5%, 5%, 4.5% and 3.5%, respectively. Meanwhile, Pseudomonas spp. detected in (19%), the most prevalent serotype was P. aeruginosa O2, O5, O9, and O11. However, the antimicrobial-resistant strains of pathogens continuously emerge, with ineffective of medical treatments, thus, the isolates were examined for detection of multidrug resistant (MDR), doxycycline exhibited the highest antimicrobial activity against Salmonella spp. (55.17%); and ceftriaxone and doxycycline against Pseudomonas spp. (52.63%). Uniplex PCR examination for ampC, stn, tetA(B), integrase genes on MGEs were detected in all Salmonella spp. isolates, and mexR, tetA (B), integrase genes in all examined MDR P. aeruginosa isolates, meanwhile, exoU detected in 80% on MGEs. A novel antibacterial strategy was achieved to minimize economic burdens and the health associated with antimicrobial resistance which obliterate pathogens without any adverse effects on poultry and human. Therefore, the application of a trial using M. Oleifera nanoemulsion in order to control the multidrug resistant genes expression. These findings demonstrated that M. oleifera nanoemulsion was a good choice to its potential as a drug that can be used against Salmonella and P. aeruginosa in poultry industry.