Synthetic chemical preservatives are widely used in the food industry to delay the deterioration caused by microbial growth, enzyme activities and oxidation reactions. The last few decades have witnessed marked interest in finding natural food preservatives due to the potential health damage of synthetic preservatives; consumers have become skeptical of consuming foods containing these additives. Polyphenols used as natural preservatives that can be extracted from fruits, vegetables, herbs and spices provide the best alternative for partial or complete replacement of their synthetic analogues. The present study’s emphasis was on employing different plant extracts to be efficiently used as antimicrobial agents for developing replacements for the synthetic chemical additives in food products. The study also investigated the antimicrobial potentialities of five medicinal plants, widely used in Egypt (sumac, tamarind, rosemary, roselle and lemon) against six microbial markers (E. coli, P. aeruginosae, B. subtilis, S. aureus, Penicillium sp. and A. niger.). Sumac extracts showed the best activity against all tested microorganisms, producing the widest inhibition zones ranging from 14 to 45 mm, followed by tamarind and roselle extracts, with inhibition zones ranging from 8–36 and 8–34 mm, respectively. On the other hand, extracts of rosemary and lemon showed variable antimicrobial activity. All extracts from all tested plants were less active against fungal species than bacterial species. In all cases, the organic extracts (80% methanol, 80% ethanol) showed the same or greater activity than the aqueous extracts. In addition, the methanolic extracts showed the strongest and broadest spectrum. The most sensitive strain to plant extracts was B. subtilis, while the most resistant strain was P. aeruginosae. The MIC and MBC or MFC values of methanolic extracts were assayed using the broth dilution method. Sumac extract showed the best activity against all tested microorganisms with the lowest values of MIC and MBC or MFC (from 0.260 to 0.877 and 0.310 to 1.316 mg/mL, respectively, for bacteria, and from 1.975 to 2.5 and 2.5 to 4.444 mg/mL, respectively, for fungi). Interestingly, the tested extracts inhibited microbial growth in tomato paste and pasteurized cow milk for a long storage period (increase shelf life) as compared to the control samples. In conclusion, herbal and spice extracts could be successfully applied as natural antimicrobials for the elimination of food borne microbes and pathogen growth.

Micrococcus luteus (M. luteus) is an emerging opportunistic fish pathogen. This study was carried out to investigate incidence of M. luteus infection among Oreochromis niloticus (O. niloticus) farms at Al Dakhla city, New Valley Governorate, Egypt through clinical and bacteriological examinations and to determine antimicrobial susceptibility of M. luteus isolates and the minimum inhibitory concentration (MIC) of silver nanoparticles (AgNPs) and zinc oxide nanoparticles (ZnONPs) against M. luteus isolates. O. niloticus samples (n=150) were collected from several farms at Al Dakhla city from March to October 2019 and they were clinically and bacteriologically examined. Suspected isolates were identified as M. luteus by the morphological and biochemical characteristics then by 16S rRNA gene sequencing and phylogenetic analysis where 14 isolates were identified as M. luteus from the examined O. niloticus with prevalence of 9.3%. M. luteus isolates were biochemically identical except in arginine dehydrolase, Vogus-Proskauer and urease tests results. O. niloticus infected with M. luteus showed excessive skin pigmentation, loss of scales, hemorrhages and ulcers on the body, congestion and rot of fins, corneal opacity, exophthalmia and congested enlarged liver, spleen and kidney. Antimicrobial susceptibility of M. luteus isolates revealed that they were sensitive to penicillin, ampicillin/sulbactam, amoxicillin/clavulanic acid, norfloxacin, chloramphenicol and tetracycline, while were resisantant to cefotaxime, amikacin, tobramycin, erythromycin and ciprofloxacin. Furthermore, it was found that MIC of AgNPs against M. luteus isolates was 100µg/ml while M. lutues isolates were resistant to all ZnONPs concentrations used in this study. This study reported fish infection with M. luteus for the first time in Egypt and its results will be a starting point for the further studies to investigate prevalence and distribution of M. luteus infection among fishes in Egypt and the plan of its prevention.

Staphylococcal infections in poultry are taking an increasing significance and both coagulase positive Staphylococci (CoPS) and coagulase negative Staphylococci (CoNS) can cause infections in poultry. On the other hand, methicillin resistance Staphylococci (MRS) is a global problem currently and MRS are often has multidrug resistance (MDR) against variety of the other antibiotics. This study was performed to investigate incidence of CoPS and CoNS and their characteristics among Japanese quails and broiler chickens in some farms at Qena Governorate Therefore, 80 Japanese quail samples of 3-4 weeks old and 70 broiler chicken samples of 21-25 days old were collected from different localities in Qena Governorate during the period from October 2020 to March 2021 for analysis. Bacterial isolates were identified as Staphylococci through phenotypic characteristics and PCR assay target 16s rRNA gene of Staphylococci, additionally CoPS were divided into Staphylococcus aureus (S. aureus) and other coagulase positive Staphylococci (OCoPS) by PCR assay target nuc gene of S. aureus. Bacteriologically, 11 Staphylococcus isolates were isolated from Japanese quail samples with percentage of (13.75%) and they identified as S. aureus (n=2), OCoPS (n=2) and CoNS (n=7) while 5 CoNS isolates were isolated and identified from broiler chicken samples with percentage of (7.14%). Examination of Staphylococcus isolates for their ability to form biofilm by Microtiter plate (MTP) and Congo Red Agar (CRA) tests revealed that all isolates were biofilm producer but with varied grades of biofilm production and the correlation rate between MTP and CRA tests for detection of biofilm-producing Staphylococci were 93.75%. Antimicrobial susceptibility testing of Staphylococcus isolates revealed that all the isolates were resistant to ampicillin, oxacillin, cefazolin, cefotaxime, vancomycin, erythromycin and clindamycin and they had antibiotic sensitivity to ciprofloxacin (87.5%) followed by gentamicin (75.0%), amoxicillin/clavulanic acid (62.5%), oxytetracycline (25%) and chloramphenicol (12.5%). On the other hand, screening Staphylococcus isolates by PCR for presence of mecA, blaz and vanA resistance genes revealed that (81.25%), (56.25%) and (31.25%) of the isolates harbor these genes respectively and each MRS harbor one gene of mecA and blaz at least. The present study demonstrates that Japanese quails and chickens harbor multidrug-resistant bacteria that could be transmitted to human.

An important food-producing sector in Egypt is aquaculture and fisheries; however, several pathogenic microorganisms lead to high mortalities and significant economic losses. The occurrence of Psychrobacter glacincola infection among 180 wild marine fishes collected from the Red sea at Hurghada, Egypt were investigated in the present study. The disease prevalence rate was 6.7%. The recovered isolates were subjected to biochemical and molecular identification. The study also investigated pathogenicity and the antibiogram profile of the recovered isolates. The clinical examination of the infected fish revealed various signs that included lethargy and sluggish movement, hemorrhages and ulcers on the body and the operculum, scale loss, and fin congestion and rot, especially at the tail fin. Furthermore, during postmortem examination, congestion of the liver, spleen, and kidney was observed. Interestingly, 12 isolates were recovered and were homogenous bacteriologically and biochemically. The phylogenetic analysis based on 16S rRNA gene confirmed that MRB62 identified strain was closely related the genus Psychrobacter and identified as P. glacincola and was pathogenic to Rhabdosargus haffara fish, causing 23.3% mortality combined with reporting a series of clinical signs similar to that found in naturally infected fishes. The present study also showed that P. glacincola isolates were sensitive to all antibiotics used for sensitivity testing. Our findings add to the body of knowledge regarding the occurrence of pathogenic P. glacincola infection in Egyptian marine fishes and its potential effects on fish. Future large-scale surveys exploring this bacterium among other freshwater and marine fishes in Egypt would be helpful for the implementation of effective strategies for the prevention and control of this infection are warranted.

Quail farms become widely spread in Egypt as a source of meat. Early mortality of quail chicks is one of quail breeding limiting factors. This study was performed to study role of some Enterobacteriaceae as a parable cause of early mortality in South Valley University quail farm, characterize isolates phenotypically and serologically, determine their antimicrobial sensitivity and to screen all isolates for presence of florfenicol resistance gene (floR), Quaternary ammonium compounds resistance gene (QacA/B) and class 1 integrons gene (Int1) and to screen E. coli, Salmonella and K. pneumoniae isolates for intimin encoding gene (eaeA), invasive encoding gene (invA) and mucoviscosity associated gene (magA) respectively. Therefore, 80 freshly dead or moribund Japanese quail chicks under 12 days of age were collected from this farm during the period from December 2020 to April 2021 for clinical assessment and bacterial isolation. Totally, 14 E. coli, 6 Salmonella and 1 K. pneumoniae isolates were isolated and phenotypically identified from the internal organs of the examined quail chicks with percentage of (17.5%), (7.5%) and (1.25%) respectively. E. coli isolates belonged to 5 different O-serogroups comprising O86 (28.6%), O78 (21.4%), O26 (14.3%), O55 (14.3%) and O164 (7.1%) in addition to 2 nontypeable isolates (14.3%) while all Salmonella isolates were serologically identified as S. Typhimurium with antigenic formula 1,4,[5],12:i:1,2. All isolates were weak biofilm producer except (33.3%) of S. Typhimurium isolates and showed Congo red binding activity except (28.6%) of E. coli isolates while only (14.3%) of E. coli isolates had hemolytic activity. Antimicrobial susceptibility testing for the isolates to 10 different antibiotics revealed that all the isolates were sensitive only to chloramphenicol and oxytetracycline except (42.9%) and (85.7%) of E. coli isolates respectively and to azithromycin except (35.7%) of E. coli isolates and K. pneumoniae. PCR revealed that all the isolates harbor Int1 and floR genes, (100%) and (33.3%) of S. Typhimurium isolates harbor invA and QacA/B genes respectively and only (21.4%) of E. coli isolates harbor eaeA and QacA/B genes. It was concluded that E. coli and S. Typhimurium are a major cause of early mortality of Japanese quail chicks.