mohammadreza sharifmoghadam

Wild birds as source of pathogenic microorganisms infecting livestock and humans are an interesting topic that has received increased attention in recent years. Here we study occurrence of pathogenic bacteria in birds in north-east Iran with focus on to identifying virulence gene in wild and domestic birds. Wild birds were trapped and sampled in different localities in north-east Iran from April to September in 2018 and 2019. From 184 birds representing 32 species of wild passerine birds, potentially pathogenic bacteria were isolated from 171 samples (92.9). Escherichia coli was the most frequently isolated bacterium with a prevalence of 70.1%, followed by Enterobacter spp. (53.8%) and Salmonella spp (3.2%) isolated from 129, 99 and 6 wild birds, respectively. In total 79.6% of the isolates carried virulence factors. A higher frequency of virulence genes was detected in domestic birds (88.6%) than in wild birds (76%). The results showed that birds in north-east Iran can serve as a potential source of bacterial pathogens and virulence factors that may cause disease in both humans and birds. Furthermore, our results introduce new host birds as source of pathogenic microorganisms that can carry and disseminate them in the environment.

Daily accumulation of feather waste due to the development of the poultry industry is a critical issue, considering the environmental and health hazards. Among feather waste disposal methods, biodegradation is a practical, cheap, and environment-friendly method. This study aimed to enhance the keratinolytic activity of FUM-2 isolate, a native keratinolytic bacterium, using mutations and culture improvement. The isolate was identified as Bacillus paralicheniformis based on biochemical, morphological, and molecular analysis. Using the one factor at a time (OFAT) method, the isolate produced more keratinase at 45 °C, pH 11, 2% carbon substrate concentration, 75% aeration rate, and 48 hours incubation. Also, it was able to degrade both α and β keratin. Culture improvement increased enzyme production from 507.6 U/mL to 1706.4 U/mL. In random mutation using ultraviolet radiation, three mutants were isolated, and a 10-minute UV-treated mutant of UVF2-D showed a 36.3% increase in keratinolytic activity compared to its parent. In the next round of mutagenesis by ethidium bromide, seven double mutants were isolated from the UVF2-D mutant, among which the EUF2-D2 double mutant showed a 79% increase in keratinolytic activity. No viable mutants were isolated from the wild strain using ethidium bromide. Our results show that many organisms can potentially produce beneficial products that could be improved using random mutagenesis and optimization methods, which are more useful for strain improvement than complex and costly molecular techniques.

Foeniculum vulgare Mill. seeds contain polyphenolic compounds which can be considered a suitable option for the green synthesis of nanoparticles.

In this study, the antibacterial activity against foodborne bacteria of ZnO nanoparticles synthesized from the aqueous extract of Foeniculum vulgare Mill. seeds was evaluated.

The synthesized ZnO nanoparticles were characterized using different analyses. The minimum inhibitory and bactericidal concentration of the nanoparticles were investigated against standard foodborne bacteria, S. aureus, Y. enterocolitica, E. coli O157:H7, and B. cereus, using the broth microdilution method.

UV-Vis spectroscopy analysis indicated an absorption peak at 231 nm which confirms the formation of ZnO nanoparticles. In addition, the X-ray diffraction pattern is consistent with the JCPDS cards, which also means the formation of ZnO nanoparticles. The results of the electron microscope revealed that the nanoparticles had a hexagonal shape with an average size of 50 nm, which is in agreement with the results obtained from the dynamic light scattering analysis. In addition, the minimum inhibitory concentration of ZnO nanoparticles against gram-negative and gram-positive bacteria, Y. enterocolitica, E. coli O157:H7, S. aureus, and B. cereus were 62.5, 62.5, 31.25 and 500 µg/ml, respectively.

ZnO nanoparticles synthesized from Foeniculum vulgare Mill. seed extract had an appropriate antibacterial effect against foodborne bacteria.

Carbapenem-resistant Acinetobacter baumannii strains are one of the most severe factors in hospital infection worldwide, in which the beta-lactamase enzyme is one of the main resistance mechanisms.

This study aimed to evaluate the presence of carbapenem-resistant beta-lactamase genes and determine antibiotic resistance patterns in the clinical isolates of A. baumannii from patients hospitalized in the Shahid Kamyab Hospital, Mashhad, Iran.

Out of 286 collected isolates from patients hospitalized in Shahid Kamyab Hospital (from March 2017 to June 2017), 31 isolates were confirmed to be A. baumannii using biochemical tests. Antibiotic susceptibility testing was conducted using the disc diffusion method according to the CLSI standard protocols. The presence of beta-lactamase genes, namely blaVEB, blaPER, blaAmpC, blaVIM, blaIMP, blaSHV , and blaTEM, was detected using polymerase chain reaction.

In this study, 31 isolates were identified as A. baumannii, all of which revealed high resistance to ceftazidime, cefixime, ceftriaxone, meropenem, imipenem, cefotaxime and cephalexin. In this case, the lowest resistance (19.35%) was observed against polymixin B. Moreover, blaAmpC, blaTEM, blaSHV , blaPER, and blaVIM were observed in 93.54% (29), 51.61% (16), 48.38% (15), 41.93% (13), and 77% (24) of the isolates, respectively. However, blaVEB and blaIMP were observed in none of the isolates.

The results showed high carbapenem resistance and high frequency of beta-lactamase resistance genes among the clinical isolates of A. baumannii.

Significant amounts of waste, including feathers, bones, blood etc. are yearly produced by the poultry industry. Feathers are composed of 90% keratin protein, and the rest is composed of lipids and water. Keratinases are one of the most diverse and usable enzymes which can be produced by bacterial and fungal microorganisms. These enzymes show a wide range of application in the various field. In this study, the keratinolytic activity of the isolated strain from a poultry farm in Mashhad was evaluated and then the medium conditions for keratinase production were optimized. The strains were identified based on the morphological and biochemical methods. 16S rRNA gene of the strain was amplified by PCR and then sequenced. And the strain proteolytic activity was examined and compared with its keratinolytic activity. Finally, strain growth ability tested in variety substrate. using 16SrRNA gene sequencing, morphological and biochemical identification, the strain shared 99/9% similarity with Bacillus mojavensis. Optimization of various factors including temperature, pH, incubation time, carbon and nitrogen sources, aeration and inoculum size showed that the isolated strain has the highest keratinolytic activity at 37°C, 48 hours incubation period, pH=9/5, sucrose 1%, 3% substrate, aeration 75% and 6% (v/v) inoculum amount. None of the nitrogen sources had a positive effect. the FUM-1 keratinolytic activity was increased approximately 3.38 fold by condition optimization of the medium, indicating the importance of environmental conditions. In the study, the strain with high keratinolytic activity was suggesting its potential use in biotechnological.

In recent years, reports of Acinetobacter strains resistant to all known antibiotics have caused a great concern in medical communities. Overexpression of efflux pumps is one of the major causes of resistance in bacteria. The aim of this study was to investigate the role of efflux pumps in conferring resistance to imipenem in clinically important Acinetobacter spp; Acinetobacter baumannii and Acinetobacter lwoffii.

A total number of 46 clinical Acinetobacter isolates, including 33 A. baumannii and 13 A. lwoffii isolates, previously collected from Shahid Kamyab and Ghaem hospitals of Mashhad, Iran were used in this study. Imipenem susceptibility testing was carried out by the disc diffusion method. Imipenem minimum inhibitory concentration (MIC) for resistant Acinetobacter isolates were determined both in the presence and absence of the efflux pumps inhibitor, carbonyl cyanide 3-chlorophenylhydrazone (CCCP).

Resistance to imipenem was observed in 38 isolates including 30 A. baumannii and 8 A. lwoffii isolates. Experiments in the presence of CCCP showed a 2 to 16384 fold reduction in imipenem MICs in 14 A. baumannii and 2 A. lwoffii isolates.

The results obtained showed high levels of resistance to imipenem and contribution of efflux pumps in conferring resistance in both Acinetobacter species in this study. Moreover, imipenem efflux mediated resistance highlights the importance of this mechanism not only in A. baumannii but also in non-baumannii Acinetobacter Spp. which have been neglected in antibiotic resistance studies.

Traditional culture methods for detection of food-borne pathogens, a major public health problem, are simple, easily adaptable and very practical, but they can be laborious and time consuming. In this study, we eliminated culturing steps by developing a new separation method and therefore, decreased the detection time of food-borne pathogens (Salmonella enterica serovar Typhimurium, Escherichia coli O157:H7 and Listeria monocytogenes) to a few hours. We used alkaline water and different alkaline buffers to elute bacteria from the lettuce surface as a model for ready-to-eat vegetables. Buffers used were as follows: 1) 0.05 M glycine; 2) 0.05 M glycine -100 mM Tris base -1% (w/v) beef extract; 3) buffer peptone water; 4) buffer phosphate saline. Buffers were adjusted to pH of 9, 9.5 and 10. In order to elute the bacteria, the lettuce pieces were suspended into buffers and shacked for 30, 45 and 60 min. Moreover, a multiplex PCR method for the simultaneous detection of food-borne pathogens was performed. The results showed that buffer peptone water at pH 9.5 for 45 min have high ability to elute bacteria from the lettuce surface and the bacteria can be detected using multiplex PCR. We developed a new rapid and efficient method for simultaneous separation of food-borne pathogens. This method eliminates culturing stages and permits the detection and identification of target pathogens in a few hours.

The development of multidrug-resistant Acinetobacter species has created serious problems in nosocomial infections. Understanding the underlying resistance mechanisms and their significance in conferring resistance to different antibiotics is the first step to develop strategies for fighting or reversing the current resistance.
The aim of this study was to investigate the role of efflux pumps in decreasing susceptibility to amikacin in Acinetobacter clinical isolates.
Forty-six clinical Acinetobacter isolates were collected from 2 teaching hospitals of Mashhad, Iran. Susceptibility testing was conducted by the disc diffusion method. Amikacin minimum inhibitory concentration (MIC) for resistant Acinetobacter isolates was determined according to the Clinical and Laboratory Standards Institute (CLSI) guidelines either with or without the efflux pumps inhibitor, carbonyl cyanide 3-chlorophenylhydrazone (CCCP). Conventional polymerase chain reaction (PCR) was used to analyze the presence of pump genes.
Acinetobacter isolates were identified as 2 species; Acinetobacter baumannii and A. lwoffii. Susceptibility testing showed high levels of resistance to amikacin in 27 isolates, including both A. baumannii and A. lwoffii, among which 20 A. baumannii isolates showed a 2- to 524288-fold reduction in amikacin MIC in the presence of CCCP, while no reduction occurred in amikacin MIC in resistant A. lwoffii isolates. The PCR results showed high frequencies of adeB, abeM, and adeI genes in Acinetobacter isolates yet the adeE gene was not found in any of the isolates.
The obtained results indicated the importance of efflux pumps in conferring resistance to amikacin in clinical isolates of A.baumannii, yet not in A. lwoffii.