Middle East Research Journal Microbiology and Biotechnology | Archives | Volume: 6 | Issue-04

Research Article

Isolation and Molecular Characterization of Heavy Metal-Resistant Bacteria from Soil and Water in Iraq

Hind Fieq Abdalameer Alhachim

Middle East Research Journal Microbiology and Biotechnology; 220-227.

https://doi.org/10.36348/merjmb.2026.v06i04.001

Heavy-metal pollution of soil and water is one of the most serious environmental problems, because these pollutants have a long half-life, are toxic, can bioaccumulate (with great ease) in biota. Objectives The objectives of the research were to isolate and identify heavy metal resistant bacteria from soil and water samples collected from some selected sites in Iraq. Samples were cultured on selective media with different heavy metals, and resistant bacterial isolates were obtained. Pheno- and molecular characterization determined the isolates with the highest tolerances for in-depth analysis. Phylogenetic analysis based on 16S rRNA gene sequencing was performed to establish the taxonomic relationship of these most resistant isolates. At least one or multiple heavy metals, some bacterial isolates that are clear such structures in adaptation to conditions of contamination exist. content In addition, some isolates had multi-metal resistant ability, suggesting tolerance mechanisms like efflux systems, biochemical detoxification and metal sequestration. The genera of the simultaneously occurred organisms recognized are often regarded to be connectional with environmental resilience and adaptability to greater macroscopic environment adverse conditions. Molecular characterization confirmed the genetic relatedness of the most tolerant isolates with resistant environmental bacteria already identified. These findings support the conclusion that native bacterial populations within Iraq's soil and water ecosystems exhibit a high tolerance threshold for heavy metals. These isolates can be used as promising candidates in bioremediation applications, especially in the development of effective and eco-friendly treatments for the removal or detoxification of heavy metals from contaminated sites. Conclusion this study points to the distribution of indigenous contaminated bacteria in various Iraqi habitats as an environmentally valuable microflora, useful with potential for developing resistance mechanisms against some antimicrobial agents and/or biotechnological significance.

Research Article

Antibiotic Resistance and Biochemical Characteristics Co- Existence among Staphylococcus aureus Exposed to Disinfectants, Photosensitizer and Laser Irradiation

Mohemid Maddallah Al-Jebouri, Hussein Saher Al-Obaidy

Middle East Research Journal Microbiology and Biotechnology; 228-244.

https://doi.org/10.36348/merjmb.2026.v06i04.002

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Background: Laser biostimulation is potentially a useful tool in the treatment of wounds, particularly those cutaneous and subcutaneous wounds that are either complicated by infection by resistant bacteria or inherently require a prolonged period of time to heal. These resistance variants which multiply in hospital environment could lead to serious epidemic outbreaks. Also, the consequence changes in phage susceptibility patterns might be affect the epidemiological reporting. Methodology: The present work was conducted on 200 patients with wounds. Their ages ranged from 1-40 years. Wound swab was taken on the third postoperative day from hospitalized patients and on the seventh postoperative day from patients attended outpatient clinic. The isolated Staphylococcus aureus isolates were subjected to susceptibility diffusion discs of penicillin, benzathine penicillin, chloramphenicol, streptomycin, gentamicin, tetracycline, erythromycin, colistin, nitrofurantoin, Fucidin and clindamycin. All strains were exposed to series of disinfectants exposure was as follow: hibitane, Dettol, cetavlon, savlon and providine-iodine. Biostimulation was carried out utilizing the laser light of Helium-Neon (He/Ne) gas type. Results: The biochemical characters were changed after disinfectants exposure and the negativity increased to urease, arginine decarboxylase and mannitol fermentation. Laser light exposure lead to an increase in negativity to certain biochemical characters like urease and Voges-Proskauer. The resistance frequency to antibiotics was decreased e.g. resistance number to chloramphenicol, benzathine penicillin and gentamicin was, and the 8, 8 and 3 respectively before exposure and then became 7, 6 and 2 respectively after laser light exposure. Conclusions: three strains were resistant to gentamicin before exposure and the number was increased to ten after second exposure to various disinfectants. Susceptibility of the ten strains to nitrofurantoin did not change after exposure. Laser light exposure led to an increase in negativity to certain biochemical characters like urease and Voges-Proskauer. The resistance of S. aureus frequency to antibiotics was decreased. The combination of laser with providine-iodine resulted in a marked reduction in both the frequency of resistant strains and the number of resistance determinants, indicating a strong synergistic antimicrobial effect.

Research Article

R-Plasmid Transfer Frequencies from Faecal Isolates of Escherichia coli of Cancer and Noncancer Patients to Escherichia coli K12 Strain

Mohemid Maddallah Al-Jebouri, Ibraheem Abdul-kareem Al-Ani

Middle East Research Journal Microbiology and Biotechnology; 245-256.

https://doi.org/10.36348/merjmb.2026.v06i04.003

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Abstract: Background: Diarrheagenic E. coli is currently categorized into a limited number of groups, primarily based on the presence of specific virulence genes, and is classified under a single pathogenic variant (pathovar). The significance of Horizontal Gene Transfer (HGT) in the evolution of the genome and pathogenicity of STEC is far more comprehensive than we previously realized. Materials and Methods: 400 patients were included and they were 200 patients with cancer diseases and 200 patients complaining of other illnesses. Specimens were taken from faeces and cultured on MacConkey agar. Isolated bacteria were identified using APIE System. Antibiotic sensitivity testing and resistance transfer from local E.coli to E.coli K12 was carried out as described elsewhere. Results: The rate of transfer of resistance traits from pathogenic E.coli to E.coli K12 was ranged between 10-6 to 10-3. The frequency of resistance transfer of carbenicillin, ampicillin and sulfonamide was 80.5, 72.1 and 62.5% respectively. The comparative analysis of antibiotic resistance patterns before and after R-factor transfer demonstrated substantial horizontal dissemination of multidrug resistance among pathogenic Escherichia coli isolates. The mean resistance-retention efficiency after conjugative transfer was 59.4%, confirming that a large proportion of resistance determinants were plasmid mediated and transmissible to recipient E. coli K12 strains. Conclusions: The rate of transfer of resistance traits from pathogenic E.coli to E.coli K12 was ranged between 10-6 to 10-3. The log–linear regression analysis demonstrated a statistically significant positive relationship between donor and recipient resistance-gene transfer frequencies among pathogenic Escherichia coli serotypes and E. coli K12 recipients (p = 0.0006). The frequency of resistance transfer of carbenicillin, ampicillin and sulfonamide was 80.5, 72.1 and 62.5% respectively. This rate of transfer was almost high than media transfer rate. There was a lower rate of transfer for nalidixic acid, colistin and nitrofurantoin and the rate was 20, 3.3 and 0% respectively. The statistical analysis demonstrated a significant positive association between the number of antibiotic-resistant Escherichia coli isolates and the frequency of resistance transfer to recipient E. coli K12 strains (Spearman r = 0.788, p = 0.0014). Overall, the findings provide strong evidence that R-factor-mediated conjugation plays a major role in the dissemination of antimicrobial resistance among pathogenic Escherichia coli populations (Figure 3). The most suitable mathematical descriptor considered was resistance-retention efficiency modeling: Retention Efficiency (%) =Before Transfer/After Transfer×100.

Research Article

Metagenomic Analysis of Antimicrobial Resistance in Wastewater and Its Environmental Impact

Dania Ali Azeiz Al-Saadi

Middle East Research Journal Microbiology and Biotechnology; 257-265.

https://doi.org/10.36348/merjmb.2026.v06i04.004

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Research Article

Evaluation of Hematological Changes Associated with Giardia Lamblia Infection in Al-Najaf Province

Abbas Nasser Hussein, Ahmed Razzaq Wajid

Middle East Research Journal Microbiology and Biotechnology; 266-273.

https://doi.org/10.36348/merjmb.2026.v06i04.005

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Abstract: Giardiasis is one of the most common intestinal protozoal infections worldwide and is caused by the flagellated protozoan Giardia lamblia. In addition to gastrointestinal manifestations, the infection may be associated with alterations in hematological parameters, particularly in patients with prolonged or recurrent infection. The present study aimed to investigate the hematological changes associated with Giardia lamblia infection among patients of different age groups in Al-Najaf Province, Iraq. A total of 375 blood samples were included in the study, comprising 250 blood samples collected from patients infected with Giardia lamblia of different ages and 125 samples obtained from apparently healthy individuals as a control group. Samples were collected from patients attending governmental healthcare institutions in Al-Najaf Province, including Al-Sadder Medical City, Al-Hakeem General Hospital, and Al-Zahraa Educational Hospital for Childbirth and Children, during the period from January 2025 to March 2026. Hematological investigations were performed to evaluate several blood parameters, including packed cell volume (PCV), hemoglobin (Hb), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), red blood cell (RBC) count, white blood cell (WBC) count, and platelet count. There were drastic changes in many hematological parameters in patients infected with Giardia lamblia, in contrast to the control group. More specifically, the WBC and platelets counts were significantly elevated in infected patients whereas PCV, MCV, MCH, MCHC and RBC numbers showed significant reductions as compare to healthy individuals (P < 0.05). The changes were all possibly representative of the influences on nutritional status, intestinal absorption, inflammatory processes and erythropoiesis associated with intestinal parasitic infection. The decrease observed in red blood cell-related indices may also indicate the development of anemia or hematological changes associated with anemia in certain infected cases. Higher WBC and platelet counts may be associated with the host inflammatory and immune responses related to parasitic infections. In conclusion, we showed significant, if modest, laboratory changes in selected hematological parameters in patients with Giardia lamblia infection and that evaluation of these parameters may provide useful adjunct superfluous information for the diagnosis of giardasis. These hematological changes should be further investigated in larger populations study with several biochemical, nutritional and immunological parameters to understand the likely underlying mechanisms responsible for these alterations.

Research Article

Impact of Demographic and Occupational Factors on Respiratory Infections among Workers of Al-Baiji Oil Refinery, Iraq

Mohemid Maddallah Al-Jebouri, Ashwaq Noori Al-Doori

Middle East Research Journal Microbiology and Biotechnology; 274-285.

https://doi.org/10.36348/merjmb.2026.v06i04.006

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Background: Respiratory tract may become susceptible to bacterial infection as a result of health conditions such as allergies and viral infections, as well as the effects of smoking and airborne environmental pollutants particularly inside oil refineries. Materials and Methods: A total number of 200 samples were taken including swabs, sputa and sera of workers in oil refinery with respiratory infections and other 200 patients who attended Tikrit Teaching hospital as control samples for comparison. Swabs and sputa were cultured. The diagnosis of bacterial isolates was done according to the microscopic examination and the results of biochemical tests. Results: The patients of refinery ranged in age between 16-65 years old, whereas those of hospital ranged between 16-95 years old who had varied jobs and some were unemployed for various reasons. G2 group forms the largest proportion of the patients from the refinery which reached 35.5 % followed by G1 group (22 %). Both who are able to perform actions that require effort, whereas G8 group formed the least proportion (3 %). This might be due to the fact that these ages include those who are at the age of retirement from work. The extent of damage is related to the pollutant's physicochemical properties, its concentration, and the duration of exposure. The most frequent cases among patients of refinery were tonsillitis (68.3 %) followed by bronchitis (13.8 %) but the same diseases formed (18.2 %) and (8.0 %), respectively in patients of hospital. Conclusions: it was noticed that males formed a proportion larger than that of females at all groups of age. In the current study it has been observed that the highest infection rates were among patients who did not exceed a period of 5 years of employment. Perhaps due to the fact that the group included newly recruited workers who had not yet adapt to pollutants exposure, followed by the groups (11-15) and (6-10) years of employment which were 20.5 % and 15 %, respectively. Periods of employment more than 16 years witnessed decreasing in infection rates and were so close between each other. The most frequent cases among patients of refinery were tonsillitis (68.3 %) followed by bronchitis (13.8 %) but the same diseases formed (18.2 %) and (8.0 %), respectively in patients of hospital. The other cases were higher in patients of hospital and they were pharyngitis (35.5%), chest infections (28.5 %), sore throat (8.0 %) and laryngitis (2.0%). In refinery the same cases revealed 3.7%, 6.4%, 6.4 % and 1.3%, respectively.

Research Article

Antibacterial Resistant Gram-Positive Bacteria in Oil Refinery Workers

Mohemid Maddallah Al-Jebouri, Ashwaq Noori Al-Doori

Middle East Research Journal Microbiology and Biotechnology; 286-300.

https://doi.org/10.36348/merjmb.2026.v06i04.007

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Background: The genetic plasticity of gram-positive bacteria is exemplified by the rapid acquisition and dissemination of resistance genes. Mobile genetic elements (MGE), plasmids, and transposons, which promote horizontal gene transfer (HGT), help spread resistance-related traits quickly. Methodology: This study was carried out in the Northern Refinery Company (NRC), one of the biggest factories in the country, which is located in the north of Baiji city. 200 samples were collected from patients worked in the Northern Refineries Company in Baiji town, equal number of samples was collected from patients hospitalized in Tikrit teaching hospital as control. Swabs taken from upper respiratory tract and sputum samples taken from lower respiratory tract, as soon as possible taken to the laboratory, were cultured on four plates of culture media recommended for primary isolation of pathogens. Antibiotic resistance was also estimated using conventional methods. Results: The minimal inhibitory concentration (MIC) ranges of antibiotics for the Staphylococcus aureus that inhibited were carried out for the groups of both refinery and hospital isolates that showed 50% of resistance or more. Most of refinery strains coagulase negative staphylococci were inhibited by 4µg/ml, while most strains of hospital were inhibited by 16µg/ml. The majority of Streptococcus pyogenes strains show MICs values ranged between 1-32 µg/ml, rarely showed < 1 µg/ml. MIC for tetracycline ranged between < 0.125 -64µg/ml among isolates of both refinery and hospital. Statistical analysis showed no significant differences in the MIC distributions of gentamicin or tetracycline between refinery and hospital isolates of Streptococcus pneumoniae. There were no statistically significant differences in the MIC distributions between refinery and hospital isolates of Micrococcaceae for amikacin, gentamicin, or tobramycin (p > 0.05 for all comparisons). Conclusions: Statistical analysis revealed that the differences in MIC distributions between R and H Staphylococcus aureus isolates were evaluated separately for each antimicrobial agent using an exact R × C contingency-table test with Monte-Carlo simulation (200,000 replicates), because of sparse cell frequencies. For coagulase negative staphylococci, Table 2 shows that MIC for amoxicillin/ clavulanic acid was ranged between 2 -64µg/ml among isolates of refinery and between 0.5 -64µg/ml among isolates of hospital. Most of refinery strains were inhibited by 4µg/ml, while most strains of hospital were inhibited by 16µg/ml. The results agreed to some extent. The majority of Streptococcus pyogenes strains show MICs values ranged between 1-32 µg/ml, rarely showed < 1 µg/ml. MIC for tetracycline ranged between < 0.125 -64µg/ml among isolates of both refinery and hospital. The MIC distributions of gentamicin and tetracycline against Streptococcus pyogenes were compared between refinery and hospital isolates using an exact R × C contingency-table analysis with Monte-Carlo simulation

Research Article

Morphological Study of Hard Ticks Infested Sheep and Goats in Al-Muthanna Province, Iraq

Rose Mohammed Naoom, Akeel Mohammad Kadim Al-Musawi

Middle East Research Journal Microbiology and Biotechnology; 301-307.

https://doi.org/10.36348/merjmb.2026.v06i04.008

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Research Article

Microscopic Examination of Sarcocystis in Meat Camels from Slaughterhouses in Al-Furat Al-Awsat, Iraq

Abdullah Hussein Yahyea, Qasim Gawad Ameer

Middle East Research Journal Microbiology and Biotechnology; 308-313.

https://doi.org/10.36348/merjmb.2026.v06i04.009

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