Egyptian Society of Biological SciencesEgyptian Academic Journal of Biological Sciences, G. Microbiology2090-087211120191201Relation of Coxsackie B3 and B4 Viral Infections for Development of type 1 Diabetes Mellitus in Children: A Case-Control Study1122557510.21608/eajbsg.2019.25575ENBilal R.M.Department of Microbiology, College of Medicine, University of AnbarMothana A.AL-ZobaeiDepartment of Microbiology, College of Medicine, University of AnbarZaid R.AL-AniDepartment of Pediatric, College of Medicine, University of Anbar, IraqJournal Article20190122<strong>Background:</strong> Human Type 1 diabetes (T1D), previously called Juvenile-onset diabetes is one of the most common chronic, multifactorial diseases of autoimmune origin with a strong genetic component, affecting about 542 000 children in the world and represents about 5-10% of all cases of diabetes. Human enteroviruses (HEVs), particularly Coxsackie B viruses (CVBs), might trigger the onset of type 1 diabetes (T1D).<br /> <strong>Objectives:</strong> Find out any relation between the Coxsackie virus type B3 & B4 infections in addition to GAD65 autoantibodies and the development of T1DM<br /> <strong>Patients and Methods:</strong> A matched case-control study was conducted and sixty cases and 120 controls were enrolled in the study.Enzyme-Linked Immunoassay (ELIZA) technique was used to detect IgM and IgG in serum against the Coxsackie B3 , B4 and GAD65 (Glutamic Acid Decarboxylase 65) autoantibodies of both cases and controls. Qualitative detection of the RNA of the Coxsackie B3 & B4 viruses in the cases and controls by the conventional PCR method using suitable primers in both cases and control. Molecular detection of the CB3 and CB4 RNA was done using according to the manufacturers’ instruction.<br /> <strong>Results:</strong>The following risk factors were found to be independently associated with illness, it were significantly associated with illness and at higher risk of T1DM : CB4 IgM Positivity (OR 47 [95% = 6.1-364.1], p = 0.0002).), CB4 RNA Positive (OR 39.6 [95%CI= 5.1 – 309], p = 0.0004 IgG Antibodies against both CVB3 and GAD65 (OR 32.9 [95%CI = 4.2 - 258.7], p = 0.0009). , GAD65 IgG Positivity (OR 11.8 [95% CI = 4.4 – 31.2], p = 0.001).and IgM Antibodies against both CB4 andGAD65 (OR 8.8 [95%CI = 2.7 – 28.2], p = 0.0002).<br /> other risk factors like CB3 IgM Positivity (OR 1.7 [95%CI = 0.6 – 4.5] p= 0.2),CB3 IgG Positivity((OR 1.3 [95%CI = 0.7-2.4], p=0.3).CB4 IgG Positivity(OR 2.1 [95%CI = 0.9-44], p = 0.06) and IgM -Antibodies against both CB3andGAD65 ((OR 1.3 [95%CI = 0.3 – 5.0], p = 0.6) with a moderately increased risk of illness, but these were not statistically significant.<br /> CB3 RNA Positive (OR 0.8 [95%CI= 0.3 -1.9] p = 0.6), GAD65 IgM Positivity (OR 0.7 [95%CI = 0.4 – 1.5], p = 0.7), IgG Antibodies against both CB4-GAD65 (OR 0.9 [95%CI = 2.9 – 8.8], p = 0.05) was not associated with illness as these were not statistically significant with the decreased risk of illness and has protective role against infection with T1D.<br /> <strong>Conclusions:</strong> We propose that children aged less than 17 years are at risk of T1D infection if exposure to CB4 whereas CB3 has protective role.https://eajbsg.journals.ekb.eg/article_25575_01974009d1c40273410e3915c934e70e.pdfEgyptian Society of Biological SciencesEgyptian Academic Journal of Biological Sciences, G. Microbiology2090-087211120191201Antibiogram of Pseudomonas aeruginosa Isolated from Burn& Wound Infections Among Inpatients and Outpatients Attending to Ramadi Teaching Hospital in Ramadi, Iraq.13222879410.21608/eajbsg.2019.28794ENMohammed A.Al.FahadawiBacteriology Department, Ramadi Teaching Hospital, Ramadi CityWaleed I.Al.ObadiMicrobiology Department, College of Medicine, AL-Anbar UniversityAbdullah S.-HasanDermatology Department, College of Medicine, Al-Anbar UniversityJournal Article20190111<strong>Background:</strong><em> Pseudomonas aeruginosa</em> is Gram- Negative bacterium and one of causing of Hospital and community-acquired infections. Over and improper use of antibiotics leads to significant changes in microbial genetic ecology of the bacterium that leads to the spread of multidrug resistance which become now a global problem. The study aimed to determine the prevalence of <em>Pseudomonas aeruginosa</em> burn &wound infections and their antibiograms toward common commercial antibiotics. <br /> <strong>Patients and Methods: </strong>Swabs were taken from patients with burn and wound infections. Specimens were examined microscopically as soon as possible (within one hour) by direct Gram-stained smears and indirectly by cultivation aerobically using suitable culture media. Bacterial isolates were diagnosed and confirmed using suitable diagnostic techniques. The antibiotics susceptibility was determined by the Kirby Bauer Disc diffusion method and the results were interpreted according to the Clinical and Laboratory Standards Institute (CLSI) guidelines2018.<br /> <strong>Results:</strong> A total of 34 isolates of <em>Pseudomonas aeruginosa</em> were isolated from a burn and wound infections during a period of six months, from September 20l8 to March 20l9. Antibiogram of <em>Pseudomonas </em>indicatedthatmost of isolates were resistant to Ceftriaxone (94.1%), Ceftazidime (94.1%), Cefotaxime (91.2%), Amikacin(61.8%), piperacillin(52.9%) and to a lesser extent to Gentamicin(35.3% ), Aztreonam(29.4%), and Tobramycin(26.5%). On the other hand most of the isolates were sensitive to Norfloxacin(76.5%), Ciprofloxacin(85.3%), Meropenem and Imipenem(91.2%)..<br /> <strong>Conclusion</strong>: Carbapenems and fluoroquinolone antibiotics appeared to be the most effective agent against <em>P. aeruginosa</em> isolates. On the other hand, cephalosporins were quite not effective against <em>P.aeruginosa</em>. https://eajbsg.journals.ekb.eg/article_28794_8e99b91cfe1517974f2d86e1350a6dfc.pdfEgyptian Society of Biological SciencesEgyptian Academic Journal of Biological Sciences, G. Microbiology2090-087211120191201Antimicrobial Activity of Sarcophaga carnaria (Diptera: Sarcophagidae) Maggots' Body Extracts23333427510.21608/eajbsg.2019.34275ENMonee S.AmerDepartment of Zoology, Faculty of Science, Al-Azhar University, Nasr City, Cairo, EgyptAhmed Z.I.ShehataDepartment of Zoology, Faculty of Science, Al-Azhar University, Nasr City, Cairo, EgyptKotb M.HammadDepartment of Zoology, Faculty of Science, Al-Azhar University, Nasr City, Cairo, EgyptAhmed I.A.HasballahDepartment of Zoology, Faculty of Science, Al-Azhar University, Nasr City, Cairo, EgyptSaed M.SaedDepartment of Zoology, Faculty of Science, Al-Azhar University, Nasr City, Cairo, EgyptJournal Article20190311The present study evaluated the antibacterial and antifungal activities of <em>Sarcophaga carnaria</em> maggots' body different extracts. The extraction was carried out using petroleum ether, hexane, acetone and ethyl acetate. The obtained results revealed that all <em>S. carnaria</em>maggots' tested extracts evoked a variable activity against both Gram-positive bacteria (<em>Staphylococcus aureus, Staphylococcus pyogenes </em>and<em> Bacillus subtilis</em>) and Gram-negative bacteria (<em>Escherichia coli, Klebsiella pneumoniae </em>and<em> Pseudomonas aeruginosa</em>) depending on the solvent used in extraction. The highest antibacterial activity (growth- inhibition zone) was 17.0±0.55 and 16.4±0.61mm obtained by petroleum ether extract against <em>S .aureus </em>and <em>S.</em> <em>pyogenes</em> (Gram-positive bacteria). Meanwhile, petroleum ether, acetone and ethyl acetate extracts showed growth-inhibition zone of 16.0±0.46, 15.4±0.50 and 16.2±0.45mm against<em> B. subtilis,</em> respectively, compared with 28.2±0.33mm for the standard <em>(Ampicillin).</em> Also, acetone extract of <em>S. carnaria</em> maggots’ whole body exhibited no activity against all tested Gram- negative bacterial strains tested. Generally, petroleum ether extraction of <em>S. carnaria</em>maggots' whole body was the most effective against different bacteria species followed by hexane, ethyl acetate and acetone extractions. Also, Gram-positive bacterial strains were more sensitive to <em>S. carnaria</em>maggots' extracts than Gram-negative bacterial strains. In addition, petroleum ether and hexane extracts of<em> S. carnaria</em> maggots' whole body showed a variable antifungal activity against <em>A. flavus, A. fumigatus, C. albicans </em>and<em>G. candidum </em>fungal strains, whereas both acetone and ethyl acetate extracts from <em>S. carnaria</em> maggots’ whole body showed no activity against all tested fungi specieshttps://eajbsg.journals.ekb.eg/article_34275_986698a2aa746987b9ebd71d56012f8f.pdfEgyptian Society of Biological SciencesEgyptian Academic Journal of Biological Sciences, G. Microbiology2090-087211120191201Bacterial Infection in Male Infertility in Al-Anbar Province West Of Iraq.35403631910.21608/eajbsg.2019.36319ENDhuha A.AbbasBacteriology Department, Falluja Teaching Hospital ,AL-Anbar provinceAbbas O.Al.janabiMicrobiology Department , College of Medicine, University of AnbarWaleedN.Surgery Department, College of Medicine , University of AnbarJournal Article20190313 <strong>Background</strong>: The role of bacterial infections on male infertility has always been controversial due to the lack of decisive analytical tools for examining seminal fluid specimens. As a result, these infectious processes lead to deterioration of spermatogenesis, impairment of sperm function and/or obstruction of the seminal tract.<br /> Aims of the study: To investigate the role of bacterial infections in male infertility in the province of Al - Anbar, western Iraq and their pattern of susceptibility to antibiotics in vitro.<br /> Patients and methods: Semen specimen were collected and processed in accordance with standard microbiology techniques for routine culture and antibiotic susceptibility.<br /> Results: Out of 80 semen samples, bacteriospermia was observed in 42(52.5%). <em>E. coli </em>took first rank of isolation (13.7%), followed by <em>Klebsiella pneumoniae </em>(11.2%), while Coagulase negative <em>Staphylococcus </em>was shown in <em>(10%). </em>Regarding antibiogram, <em>E. coli </em>was found to be susceptible to Meropenem (100%), followed by Amikacin(81.8%) and Levofloxacin (81.8%).<br /> Conclusion:We can conclude from the study that is semen culture is an important diagnostic tool for all patients undergoing fertility investigations and bacteriospermia is an important cause of infertility, and for empirical treatment levofloxacin and meropenem seems to be drug of choice. The regular screening of bacterial pathogen in infertile man seems necessary because it affects infertility in several wayshttps://eajbsg.journals.ekb.eg/article_36319_bbcb99268cacd5bb116de745e000a2d1.pdfEgyptian Society of Biological SciencesEgyptian Academic Journal of Biological Sciences, G. Microbiology2090-087211120191201Antibiogram of Klebsiella pneumonia, Acinetobacter bumannii and Proteus mirabilis Isolated From Patients with Traumatic Wounds in Ramadi Teaching Hospital41464733810.21608/eajbsg.2019.47338ENShehab A.LafiHOD. Microbiology Dept. College of Medicine University of Anbar, IRAQMahmoodAl-ShamarryClinical Lab. Ramadi Teaching HospitalMohamed S.AhmedDeputy of Anbar Health Office.Journal Article20190501<strong>Background:</strong> Traumatic wounds exposed to many microbial contaminants through contaminated tools causing these types of wounds . At the same time treatment of wounds is difficult because of antimicrobial resistance to many available antibiotics and transfer between bacterial generations. <br /> Aims of the study: This study was done to show the bacterial profile and the antibiogram of <em>Proteus mirabilis , Acinetobacter bumannii and Klebsiella pneumoniae</em>, a preserved bacterial isolates from a previous study.<br /> <strong>Material and Methods</strong>: Twenty- seven (27 ) deep frozen preserved bacterial isolates <em>Proteus mirabilis</em>. , <em>Acinetobacter bumannii </em>and<em> klebsiella pneumonia </em> Obtained from Department of Microbiology, College of Medicine , University of Anbar and were used to investigate the antibiogram profile. Frozen bacterial isolates were reactivated on blood culture medium at 37 C° for overnight and re-identified to confirm bacterial type and antibiogram findings by using using Viteck2 system. <br /> <strong><em>Results </em></strong><em>: Klebsiella pneumonia showed 100% sensitivity </em>to Imipenium , Meropenim , Eatrapenim and Levofloxacin, while 75% of isolates were sensitive to Amikacin and Ciprofloxacin . Eighty percent ( 80% ) of isolates were resistant to Cefotaxim , Ceftriaxone and Rifampicin. All isolates of <em>Proteus merabilis </em>(100% ) were sensitive to Levofloxacin and meropenem followed by 90% sensitivity to Imepenium and Amikacin. All isolates ( 100% ) were resistant to Cefotaxim followed by 90% & 70 %, resistance to Ceftriaxone , Refadin respectively. Seventy- five percent (75% ) of <em>Acinetobacter bumannii</em> isolates`were sensitive to Levofloxacin while 50% of isolates were sensitive to Ciprofloxacin and Amikacin followed by 25 % sensitivity to Imepenium , Meropenem & Gentamycin. All isolates (100%) were resistant to Ceftriaxone , Augumentin ,Ampiclox and Cefotaxim . So we recommend a continuous study of bacterial profile for wound infections both traumatic and surgical wounds because the profile of infection undergo difference through yearhttps://eajbsg.journals.ekb.eg/article_47338_434658ad0d5bbfc30223b168a8f2b3eb.pdfEgyptian Society of Biological SciencesEgyptian Academic Journal of Biological Sciences, G. Microbiology2090-087211120191201Biosynthesis, Characterization and Cytotoxicity of Selenium Nanoparticles Using Bacillus tropicus Ism 247575526910.21608/eajbsg.2019.55269ENOmnia MohamedAbdallahDepartment of Microbiology, Faculty of Dentistry, Misr International University, Cairo, EgyptKhaled Z.EL-BaghdadyDepartment of Microbiology, Faculty of Science, Ain Shams University, Cairo, EgyptMostafa M.H.KhalilDepartment of Chemistry, Faculty of Science, Ain Shams University, Cairo, EgyptMervat I.El Borhamy-Department of Microbiology, Faculty of Pharmacy, Misr International University, Cairo, Egypt
-International Medical Center, Clinical Microbiology Laboratory, Cairo, EgyptGamalMeligiDepartment of Chemistry, Faculty of Science, Ain Shams University, Cairo, EgyptJournal Article20191004 Green biosynthesis of selenium nanoparticles (SeNPs) using <em>Bacillus tropicus</em> Ism 2 (MK332444) isolated from soil polluted with industrial wastewater near the Ismailia Canal, Egypt, was carried out. SeNPs were biogenically synthesized using bacterial pellets mixed with 1 mM Na<sub>2</sub>SeO<sub>3</sub>. Characterization of biosynthesized SeNPs was carried out by UV-Vis spectrum where SeNPs solution exhibited characteristic peak at 270 nm. Dynamic Light Scattering (DLS) analysis and High-Resolution Transmission Electron Microscope (HRTEM) showed spherical shaped SeNPs with size ranged from 60 to 125 nm with PDI= 0.544 and zeta potential value of -30.6. Biologically synthesized SeNPs showed no antibacterial activity against both Gram-positive and Gram-negative bacteria. Cytotoxicity of SeNPs was studied against Huh-7 human liver cell line and showed low cytotoxicity with IC<sub>50 </sub>value of367±5.5 μg/ml. In conclusion in this work <em>Bacillus tropicus</em> Ism 2 locally isolated bacterium showed the capability to biosynthesize SeNPs with spherical shape and low cytotoxicity. https://eajbsg.journals.ekb.eg/article_55269_1ec4195c068f4282d9adf0d9f166a6d8.pdfEgyptian Society of Biological SciencesEgyptian Academic Journal of Biological Sciences, G. Microbiology2090-087211120191201Possibility of Reducing Presence of Harmful Fungi in Air-Conditioner Windows Using A Transcendental Antifungal Chemical59706907210.21608/eajbsg.2019.69072ENShaima M. N.MoustafaDepartment of Botany and Microbiology, Faculty of Science, Minia University, El-Minia, 61511, EgyptJournal Article20191006Fungi are usually spread in humid areas, even if they are scarce in nutrients, which can capture a small amount of them from the surrounding air. Fungi in air-conditioner windows were studied in 13 air conditioners in houses located in Sakaka city, Jouf, Saudi Arabia, in the spring of 2018. Air passages inside these air conditioners are suitable environments for the occurrence of fungi. This research was designed to reveal the presence of dangerous fungi in air passages of these conditioners and to find suitable practical ways to eliminate these harmful taxa. Isolated fungi were identified using morphological and ultrastructure criteria and were Aspergillus niger, <em>Chaetomium globosum, Penicillium frequentans, Penicillium italicum</em>, <em>Paecilomyces lilacinus, and </em><em>Xanthophyllomyces dendrorhous</em>. Results showed that <em>Aspergillus niger</em>, <em>Paecilomyces lilacinus,</em> and <em>Penicillium italicum</em> caused severe decomposition of in human blood red cells, the strongest of which was the fungus <em>Paecilomyces</em>. The aromatic pungent smell of transcendental naphthalene has been shown to have an inhibitory effect on three of the isolated fungal species. Transcendental naphthalene inhibited mycelium growth of <em>Aspergillus niger</em>, <em>Penicillium frequentans</em> and <em>Penicillium italicum</em> by 100% while never affecting <em>Paecilomyces lilacinus</em>. The study recommends further studies on the presence of fungi in the air - driven corridors of air conditioners in different countries and devising new ways to reduce the presence of fungi. https://eajbsg.journals.ekb.eg/article_69072_9d753ff4a9c86fa9e2c7249c2482dd0b.pdfEgyptian Society of Biological SciencesEgyptian Academic Journal of Biological Sciences, G. Microbiology2090-087211120191201Detection and Importance of Some Pathogenic Bacteria in Psittascine Birds with Special Reference to the Virulence Genes71878062510.21608/eajbsg.2019.80625ENGhada A.IbrahimAHRI, Ismailia branch, BacteriologyFatma A.YoussefAHRI, Ismailia branch, PathologyAmal S.El-OkshRLQP, Zagazig branch, BacteriologyJournal Article20191006 Psittascine birds are potential carriers and/or transmitters of some pathogenic bacteria, which have an important impact on human health. The scope of this study was to survey, isolate and identify some pathogenic bacteria in psittascine birds with special regard to plasmid detection of some virulent and resistance genes. A total of 120 samples (85 from different birds, 35 samples from their surrounding) were collected for microbiological investigations. All isolates were submitted to antimicrobial susceptibility testing and discussed in details. <em>E. </em>coliwas the predominant isolate in all examined birds (34.11%) followed by<em> Staphylococcus</em> spp < em>. (32.9%) and<em> Salmonella </em>spp < em>. (12.9%). <em>E. </em>coliof O78 was the most prevalent serotype detected in all samples also; <em>Salmonella Typhymurium</em> was the most frequent serovar in all recovered<em> Salmonella </em>spp. isolates. Plasmid detection of <em>crl</em> and <em>eae</em>Avirulence genes of <em>E. </em>coliisolates were found in (100% and 33.3%, respectively). Also, all examinedisolates of <em>Salmonella </em>spp < em>. and<em> Staphylococcus</em> spp < em>. showed the presence of (<em>inv</em>A, <em>stn</em> and <em>fim</em>H) and (<em>clf</em>Aand <em>ica</em>A) virulence genes in (100%, for each), respectively. Meanwhile, screening for antibiotic resistance genes (<em>dfr</em>A,<em> tet</em>A, <em>bla</em><em>TEM</em>, <em>qnr</em>A, <em>nor</em>A and<em> bla</em>Z) of <em>E. </em>coli, <em>Salmonella</em> spp < em>. and <em>Staphylococcus </em>spp., respectivelywere detected on all relative plasmid profiles (100%, for each). In conclusion, several bacterial pathogens were isolated from psittascine birds so, it is recommended to apply good biosecurity management and good hygiene with competent and quality veterinary care in birds/ pets breeding, with preventive guidelines. Also, due to the zoonotic nature of some bacteria, it is very important that pet bird owners should be trained well to practice good hygiene when handling / breeding their pets to limit the risk of zoonotic diseases.https://eajbsg.journals.ekb.eg/article_80625_4905645294f861adf71b2c14b49cd526.pdfEgyptian Society of Biological SciencesEgyptian Academic Journal of Biological Sciences, G. Microbiology2090-087211120191201Stimulating Gamma-Linolenic Acid Productivity by Arthrospira platensis (Spirulina platensis) Under Different Culture Conditions (Temperatures, Light Regime, and H2O2 stress)89998501410.21608/eajbsg.2019.85014ENJelanMofeedDepartment of Aquatic Environment, Faculty of Fish Resources, Suez University, EgyptJournal Article20191026 <em> Arthrospira platensis</em> considered a storehouse rich in nutritionally active compounds with dietary and pharmaceutical applications. Gamma-Linolenic acid (GLA) or ώ-6, which characterized by several therapeutic properties, can be obtained safely from <em>A. platensis</em>. This study aimed to stimulate GLA productivity by <em>A. platensis</em>, through using different culturing conditions of temperature and light regime as well as hydrogen peroxide. The obtained results reflected that continuous lighting regime (24L) enhances the production of the unsaturated fatty acid especially GLA than the regime of 12 hours darkness: 12 hours lighting (12D:12L), at the same time low temperature (24<sup>o</sup>C) enhance GLA productivity (29.98 mg. g<sup>-1</sup> dry weight). Although hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) did not support biomass production, its low concentrations induced the GLA productivity. The cited results clarified that the maximum GLA (31.62 mg. g<sup>-1</sup>) was obtained under continuous lighting regime, at 24<sup>o</sup>C by adding 2 mM H<sub>2</sub>O<sub>2</sub>, forming 27.42% from the total fatty acids. Nevertheless, with the increase in population accompanied by increasing their needs, researchers will compete to obtain the maximum productivity of <em>A.</em> <em>platensis</em> for GLA with its numerous therapeutic properties.https://eajbsg.journals.ekb.eg/article_85014_f9ef1cf8eadbf7356b90f2e007d7ba4a.pdfEgyptian Society of Biological SciencesEgyptian Academic Journal of Biological Sciences, G. Microbiology2090-087211120191201Isolation and 16s rRNA Identification of Micro Organisms from Drinking Water1011098795710.21608/eajbsg.2019.87957ENDoaa K.El-Ghareeb1-Biology Department, Al-Jumum University College, Umm Al-Qura University, Makkah, Saudi Arabia
2-Agricultural Genetic Engineering Research Institute (AGERI), ARC, Giza, EgyptRasha M.Alreedy2-Agricultural Genetic Engineering Research Institute (AGERI), ARC, Giza, Egypt
3- Department of Biology, College of Science, Taibah University, Madina, Saudi ArabiaMahmoud S.MohamedDepartment of Botany and Microbiology, Faculty of Science, Cairo University, 12613, Giza, EgyptGamal E. H.Osman2-Agricultural Genetic Engineering Research Institute (AGERI), ARC, Giza, Egypt..6-Research Laboratories Centre, Faculty of Applied Science, Umm Al-Qura University, Makkah, Saudi Arabia.Journal Article20191028Water is one of the most important elements for all forms of life and is indispensable in the maintenance of life on Earth and essential for the composition and renewal of cells. Water represents 70% of our body, participates in the composition of our tissues, and transports the most diverse substances throughout our organism. Notwithstanding, human beings increasingly continue to pollute the reserves which remain, provoking illnesses that can jeopardize the population [http://www.sabesp.com.br] web site Bioaccumulation, sewerage, agricultural, industrial, radioactive, and thermal residues are the principal polluters of water on our planet.https://eajbsg.journals.ekb.eg/article_87957_f6e1b642515049cffa0e2a4c4e5ecf8f.pdfEgyptian Society of Biological SciencesEgyptian Academic Journal of Biological Sciences, G. Microbiology2090-087211120191201A New Bacterial Strain Alcaligenes aquatilis MAG 1 Associated with the Mediterranean Sea Lithophaga (Bivalvia) Precipitating in Nutrient Free Medium Shell-Like Calcium Carbonate Polymorphs11112415353310.21608/eajbsg.2019.153533ENMagda M.MehanniDepartment of Botany and Microbiology, Faculty of Science, Minia University, Minia 61519, EgyptShaban H.Abd El-AzizDepartment of Zoology and Entomology, Faculty of Science, Minia University, Minia 61519, EgyptJournal Article20191029Mediterranean Sea <em>Lithophaga</em> bivalve associated bacteria and their capability in calcium carbonate polymorphs formation have been investigated in the present study. Isolated bacteria were a single strain of Gram-negative, rod-shaped, and flagellated motile cells. Phylogenetic analysis based on 16S rDNA sequences consigned the isolated bacterium to<em> Alcaligenes aquatilis</em> species as a distinct strain assigned as <em>Alcaligenes aquatilis</em> strain MAG 1. Phenotypic and biochemical characteristics of the strain recorded no acids produced from different carbohydrates under aerobic conditions except for D-mannose, amygdalin, glucose, L-rhamnose, L- arabinose and D- melibiose. Isolates showed negative results for nitrate reduction, urea degradation, sulphate reduction (H<sub>2</sub>S production) and tryptophan deaminase (TDA). <em>Alcaligenes aquatilis</em> strain MAG 1 precipitated in nutrient-free medium different polymorphs of anhydrous CaCO<sub>3</sub>, initially, as a mixture of aragonite and calcite, and well-organized rhombohedral calcite crystals dominated by the fourth day. Conclusively, calcium carbonate biomineralization away from any added nutrients by this new strain magnifies its role as nucleation sites and retracts the effect of bacterial metabolic pathways. Besides, various CaCO<sub>3</sub> crystal polymorphs formed by the isolated strain advocate a potential complementary role in <em>Lithophaga</em> shell assembly. https://eajbsg.journals.ekb.eg/article_153533_3b6af6488d9710fb76c679f0e62da0a4.pdf