Tehran University of Medical Sciences Iranian Journal of Microbiology 2008-3289 15 5 2023 10 11 601 608 Nesma Mohamed Department of Medical Microbiology and Immunology, Faculty of Medicine, Sohag University, Sohag, Egypt Mohamed Alrawy Department of Clinical and Chemical Pathology, Faculty of Medicine, Sohag University, Sohag, Egypt Reem Makbol Department of Tropical Medicine & Gastroenterology, Faculty of Medicine, Sohag University, Sohag, Egypt Arafat Mohamed Department of Otorhinolaryngology, Sohag University, Sohag, Egypt Shimaa Hemdan Department of Medical Biochemistry, Sohag University, Sohag, Egypt Noha Shafik Department of Medical Microbiology and Immunology, Faculty of Medicine, Sohag University, Sohag, Egypt 2023 06 08 2023 08 24 Background and Objectives: The type VI secretion system (T6SS) was identified as a novel virulence factor in many Gram-negative bacteria. This study aimed to investigate the frequency of the T6SS genes in Klebsiella pneumoniae-causing different nosocomial infections, and to study the association between T6SS, antibiotic resistance, and biofilm formation in the isolated bacteria. Materials and Methods: A total of fifty-six non-repetitive K. pneumoniae isolates were collected from different inpatients admitted at Sohag University Hospital from September 2022 to March 2023. Samples were cultured, colonies were identified, and antimicrobial sensitivity was done by VITEK® 2 Compact. Biofilm formation was checked using Congo red agar method. T6SS genes, and capsular serotypes were detected by PCR. Results: Fifty-six K. pneumoniae isolates were obtained in culture. 38 isolates (67.86%) produced biofilm and 44 (78.57%) were positive for T6SS in PCR. There was a significant association between the presence of T6SS and resistance to the following antibiotics: meropenem, ciprofloxacin, and levofloxacin. All biofilm-forming bacteria had T6SS, with significant differences towards T6SS -positive bacteria. There was no significant association between T6SS, and the presence of certain capsular types. Conclusion: The T6SS-positive K. pneumoniae has greater antibiotic resistance, and biofilm-forming ability which is considered a potential pathogenicity of this emerging gene cluster. https://ijm.tums.ac.ir/index.php/ijm/article/view/4255 https://ijm.tums.ac.ir/index.php/ijm/article/download/4255/1605

Tehran University of Medical Sciences Iranian Journal of Microbiology 2008-3289 15 5 2023 10 11 609 615 EN Fatemeh Ghanbarinasab Department of Animal Biology, Faculty of Natural Sciences, University of Tabriz, Tabriz, Iran Mehri Haeili Department of Animal Biology, Faculty of Natural Sciences, University of Tabriz, Tabriz, Iran Somayeh Nasiri Ghanati Department of Animal Biology, Faculty of Natural Sciences, University of Tabriz, Tabriz, Iran Mohaddeseh Moghimi Department of Animal Biology, Faculty of Natural Sciences, University of Tabriz, Tabriz, Iran 2023 06 20 2023 08 13 Background and Objectives: Klebsiella pneumoniae is increasingly developing resistance to last-resort antibiotics such as carbapenems. This study aimed to investigate the dissemination of common carbapenemase encoding genes among 48 clinical isolates of carbapenem-resistant Klebsiella pneumoniae (CRKP). Materials and Methods: Antimicrobial susceptibility testing was performed by broth dilution and disc diffusion methods. The phenotypic evaluation of carbapenemase production was performed by using Modified Carbapenem Inactivation Method. Presence of carbapenemase encoding genes blaKPC, blaNDM, blaOXA-48-like, blaIMP, and blaVIM was screened by PCR. Results: Overall, carbapenemases were produced in all CRKP isolates. The blaOXA-48-like and blaNDM were the most prevalent genes detected among all and 66.6% (n=32) of CRKP isolates respectively. The blaVIM was detected in only one isolate co-harboring NDM and OXA-48-like carbapenemases. The blaKPC and blaIMP genes were not identified in any of the isolates. While tigecycline was the most active agent against CRKP isolates with low resistance rate (4.1%), high rate of resistance was observed to colistin (66.6%), amikacin (79%) and most of other tested antimicrobials. Conclusion: Our results revealed predominant prevalence of OXA-48-like and NDM carbapenemases among CRKP clinical isolates. High rate of resistance to last-resort agents such as colistin among CRKP isolates is a source of great concern. https://ijm.tums.ac.ir/index.php/ijm/article/view/4277 https://ijm.tums.ac.ir/index.php/ijm/article/download/4277/1606

Tehran University of Medical Sciences Iranian Journal of Microbiology 2008-3289 15 5 2023 10 11 616 624 Samane Mohebi Department of Bacteriology and Virology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran Zahra Golestani-Hotkani Department of Biosciences, University of Milan, Milan, Italy Maryam Foulad-Pour Clinical Research Development Unit, Afzalipour Hospital, Kerman University of Medical Sciences, Kerman, Iran Peivand Nazeri Clinical Research Development Unit, Afzalipour Hospital, Kerman University of Medical Sciences, Kerman, Iran Fahimeh Mohseni Student Research Committee, Kerman University of Medical Sciences, Kerman, Iran Zahra Hashemizadeh Department of Bacteriology and Virology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran Zahra Moghani-Bashi Clinical Research Development Unit, Shahid Bahonar Hospital, Kerman University of Medical Sciences, Kerman, Iran Naser Niksefat Student Research Committee, Kerman University of Medical Sciences, Kerman, Iran Sanaz Rastegar Medical Mycology and Bacteriology Research Center, Kerman University of Medical Sciences, Kerman, Iran Maryam Khajedadian Student Research Committee, Kerman University of Medical Sciences, Kerman, Iran Zahra Lotfian Student Research Committee, Kerman University of Medical Sciences, Kerman, Iran Hossein Hosseini-Nave Medical Mycology and Bacteriology Research Center, Kerman University of Medical Sciences, Kerman, Iran 2023 03 16 2023 10 11 Background and Objectives: The study aimed to investigate the distribution of genes encoding integrons, extended spectrum beta-lactamase (ESBL) in E. coli isolated from UTIs, as well as the genetic diversity among the isolates. Materials and Methods: E. coli isolates were recovered from the patients with UTI in Kerman Iran. Antibiotic susceptibility was done according to CLSI guidelines. The presence of ESBL genes and integrons was evaluated using PCR. PCR and sequencing were applied for the evaluation of cassette content of integrons. Genotyping of the isolates was performed by multiple-locus variable-number tandem repeat analysis (MLVA). Results: Imipenem was the most effective antibiotic, while the highest resistance was observed to streptomycin. In total 40.2% of isolates were ESBL producers. Of 69 integron-positive isolates, 59 only had class I integrons, 4 only had class II integrons and 6 had both types. The most common gene cassette found within class I integrons was dfrA17-aadA5 (n=27). The E. coli isolates were divided into 16 MLVA clusters. Conclusion: The current study demonstrated the simultaneous presence of class I integrons and ESBLs involved in the resistance of UPEC isolates to antibacterial agents. Our finding also revealed that the E. coli isolates belonged to diverse clones. https://ijm.tums.ac.ir/index.php/ijm/article/view/4157 https://ijm.tums.ac.ir/index.php/ijm/article/download/4157/1607

Tehran University of Medical Sciences Iranian Journal of Microbiology 2008-3289 15 5 2023 10 11 625 630 Nabi Jomehzadeh Department of Microbiology, School of Medicine, Abadan University of Medical Sciences, Abadan, Iran Khadijeh Ahmadi Department of Microbiology, School of Medicine, Abadan University of Medical Sciences, Abadan, Iran Nazanin Ataee Department of Biology, Kavian Institute of Higher Education, Mashhad, Iran Maryam Afzali Department of Microbiology, Faculty of Medicine, Mashhad Medical Sciences, Islamic Azad University, Mashhad, Iran; Department of Laboratory Sciences, Faculty of Paramedicine, Mashhad Medical Sciences, Islamic Azad University, Mashhad, Iran 2023 02 05 2023 04 24 Background and Objectives: An increase in the antibiotic resistance of Shigella isolates has caused major global challenges in antimicrobial therapy. Knowledge of local antibiotic resistance trends is essential for selecting appropriate antibiotic treatment regimens. This study aimed to evaluate the frequency of efflux-mediated tetracycline resistance (tet) and plasmid-mediated quinolone resistance (qnr) genes among Shigella isolates. Materials and Methods: This survey investigated 91 Shigella isolates, obtained from children with acute diarrhea. The isolates were identified using standard biochemical tests and confirmed by polymerase chain reaction (PCR) assay. Besides, the susceptibility of isolates to six selected antibiotics was assessed by the disk diffusion method. All tetracycline-resistant and nalidixic acid and ciprofloxacin resistant strains were screened for tet and qnr genes by a multiplex PCR assay. Results: According to the results of antibiotic susceptibility tests, the highest level of antibiotic resistance was related to tetracycline (80.2%) and doxycycline (78.1%), respectively. All isolates were sensitive to tigecycline. The PCR results showed that 40.6%, 3.1%, 21.8%, 61.6% and 28.7% of the isolates carried qnrA, qnrB, qnrS, tetA, and tetB genes, respectively. None of the isolates contained tetC and tetD genes. Conclusion: The current findings revealed that tetA and qnrA genes might play a key role in conferring tetracycline and quinolone resistance. https://ijm.tums.ac.ir/index.php/ijm/article/view/4115 https://ijm.tums.ac.ir/index.php/ijm/article/download/4115/1608

Tehran University of Medical Sciences Iranian Journal of Microbiology 2008-3289 15 5 2023 10 12 631 641 Reza Khaltabadi Farahani Department of Molecular Biology, Pasteur Institute of Iran, Tehran, Iran; Department of Molecular, Central Veterinary Laboratory, Iranian Veterinary Organization, Tehran, Iran Mina Ebrahimi-Rad Department of Biochemistry, Pasteur Institute of Iran, Tehran, Iran Nader Shahrokhi Department of Molecular Biology, Pasteur Institute of Iran, Tehran, Iran Amir Hossien Khaltabadi Farahani Department of Animal Science, Faculty of Agriculture and Natural Resources, Arak University, Arak, Iran Seyed Ali Ghafouri Department of Clinical Sciences, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad, Mashhad, Iran Maryam Rezaei Department of Molecular Biology, Pasteur Institute of Iran, Tehran, Iran Safoora Gharibzadeh Department of Epidemiology, Pasteur Institute of Iran, Tehran, Iran Arash Ghalyanchi Langeroudi Department of Microbiology and Immunology, School of the Veterinary Medicine, University Tehran, Tehran, Iran Parastoo Ehsani Department of Molecular Biology, Pasteur Institute of Iran, Tehran, Iran 2023 01 18 2023 10 12 Background and Objectives: Antibiotic resistance is an indicator of the passively acquired and circulating resistance genes. Salmonella Gallinarum significantly affects the poultry food industry. The present study is the first study of the S. Gallinarum biofilm in Iran, which is focused on the characterization of the S. Gallinarum serovars and their acquired antibiotic resistance genes circulating in poultry fields in central and northwestern Iran. Materials and Methods: Sixty isolates of S. Gallinarum serovar were collected from feces of live poultry. The bacteria were isolated using biochemical tests and confirmed by Multiplex PCR. Biofilm formation ability and the antibacterial resistance were evaluated using both phenotypic and genotypic methods. The data were analyzed using SPSS software. Results: According to Multiplex PCR for ratA, SteB, and rhs genes, all 60 S. Gallinarum serovars were Gallinarum biovars. In our study, the antibiotic resistance rate among isolated strains was as follows: Penicillin (100%), nitrofurantoin (80%), nalidixic acid (45%), cefoxitin (35%), neomycin sulfate (30%), chloramphenicol (20%), and ciprofloxacin (5%). All isolates were susceptible to imipenem, ertapenem, ceftriaxone, ceftazidime, and ceftazidime+clavulanic acid. All sixty isolates did not express the resistance genes IMP, VIM, NDM, DHA, blaOXA48, and qnrA. On the other hand, they expressed GES (85%), qnrB (75%), Fox M (70%), SHV (60%), CITM (20%), KPC (15%), FOX (10%), MOXM (5%), and qnrS (5%). All S. Gallinarum isolates formed biofilm and expressed sdiA gene. Conclusion: Considering that the presence of this bacteria is equal to the death penalty to the herd, the distribution of resistance genes could be a critical alarm for pathogen monitoring programs in the region. This study showed a positive correlation between biofilm formation and 50% of tested resistance genes. Also, it was found that the most common circulating S. gallinarum biovars are multidrug-resistant. https://ijm.tums.ac.ir/index.php/ijm/article/view/4091 https://ijm.tums.ac.ir/index.php/ijm/article/download/4091/1609

Tehran University of Medical Sciences Iranian Journal of Microbiology 2008-3289 15 5 2023 10 12 642 653 Ni Nengah Dwi Fatmawati Department of Clinical Microbiology, Faculty of Medicine, Udayana University, Bali, Indonesia Gede Ngurah Rsi Suwardana Department of Clinical Microbiology, Faculty of Medicine, Udayana University, Bali, Indonesia Ida Ayu Gde Wahyudevi Dharmika Department of Clinical Microbiology, Faculty of Medicine, Udayana University, Bali, Indonesia Ni Made Adi Tarini Department of Clinical Microbiology, Faculty of Medicine, Udayana University, Bali, Indonesia I Nengah Sujaya Department of Public Health and Pre of dogs and cats, their association with periodontal disease, and the possibility of a common source of infections between humans and companion animals is of great importance for the management of oral health in animals and humans. https://ijm.tums.ac.ir/index.php/ijm/article/view/5330 https://ijm.tums.ac.ir/index.php/ijm/article/download/5330/1817

Tehran University of Medical Sciences Iranian Journal of Microbiology 2008-3289 17 5 2025 10 14 725 733 Aya Maytah Department of Basic Sciences, Ma′an University College, Al-Balqa Applied University, Ma′an, Jordan Omar AlKofahi Department of Medical Laboratory Science, Faculty of Allied Medical Sciences, Zarqa University, Zarqa, Jordan Rania Al-Groom Department of Medical Laboratory Science, Faculty of Allied Medical Sciences, Zarqa University, Zarqa, Jordan; Department of Allied Medical Sciences, Zarqa University College, Al-Balqa Applied University, Zarqa, Jordan Mohd Sajjad Ahmad Khan Department of Basic Sciences, Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia Basem Fouad Dababneh Department of Medical Laboratory Sciences, Faculty of Allied Medical Sciences, Al-Ahliyya Amman University, Amman, Jordan Anas Da'meh Department of Medical Laboratory Science, Faculty of Allied Medical Sciences, Zarqa University, Zarqa, Jordan Rahaf Alsarayereh Department of Medical Laboratory Science, Faculty of Allied Medical Sciences, Zarqa University, Zarqa, Jordan Fuad Alhawarat Department of Applied Medical Sciences, Al Hussein Bin Abdullah II Academy for Civil Protection, Al-Balqa Applied University, Salt, Jordan Heba Ahmad Al Shqairat Precision Medical Lab (PMLAB), AL-Karak, Jordan 2025 07 08 2025 08 22 Background and Objectives: Acinetobacter baumannii (A. baumannii) is an opportunistic bacterial pathogen principally related with hospital-acquired infections. This study aimed to isolate and identify A. baumannii strains, investigate their resistance to various antibiotics, and characterize A. baumannii at the molecular level. Materials and Methods: A total of 100 samples were obtained from various hospital departments, including the intensive care unit (ICU), emergency room, kidney dialysis and surgery units. The incidence of drug resistance was studied using the Vitek 2 Compact system and further using molecular techniques such as polymerase chain reaction to analyze the genes responsible for resistance. Results: The study exhibited a high prevalence of multidrug-resistant (MDR) A. baumannii isolates, especially in ICU patients. The males were the predominant group, accounting for 60% whereas females were 40%. The most frequent samples were from urine (43%) and skin (24%). Majority of samples were from the ICU (42%) and emergency departments (20%). The tested isolates exhibited the highest resistance (66%) to oxacillin, whereas the maximum sensitivity (52%) was recorded for Erythromycin. Molecular analysis revealed the occurrence of resistance genes blaOXA-23, blaOXA-24, blaOXA-51, and blaOXA-58, which contribute to carbapenem resistance. Conclusion: The findings emphasize that A. baumannii remains a formidable nosocomial pathogen, and there is pressing requirement for enhanced infection control procedures and antibiotic stewardship. Through improved molecular observation, judicious use of antibiotics and improved infection control practices, healthcare providers can alleviate the impact of MDR A. baumannii infections and improve the prognosis for affected patients in Jordan and beyond. https://ijm.tums.ac.ir/index.php/ijm/article/view/5606 https://ijm.tums.ac.ir/index.php/ijm/article/download/5606/1818

Tehran University of Medical Sciences Iranian Journal of Microbiology 2008-3289 17 5 2025 10 14 734 740 Hayder Ali Department of Biology, College of Science, University of Al-Qadisiyah, Al Diwaniyah, Iraq Dhuha Jabir Department of Biology, College of Science, University of Al-Qadisiyah, Al Diwaniyah, Iraq Zainab Falih Department of Biology, College of Science, University of Al-Qadisiyah, Al Diwaniyah, Iraq Salam Najm Department Diwaniyah Health, Ministry of Health, Al Diwaniyah, Iraq 2025 05 01 2025 07 23 Background and Objectives: Hypermucoviscous Klebsiella pneumoniae exhibits distinct phenotypic and genetic characteristics that distinguish it from the classic K. pneumoniae pathogen. The aim of current study was to investigate some phenotypic and genetic markers used for hmKp identification. Materials and Methods: Seventy-one K. pneumoniae isolates were obtained from the respiratory care unit in Al-Diwanyiah Teaching Hospital \Diwanyah, Iraq, from the first of November 2024 to the first of March 2025. The bacteria were identified, and antibiotic sensitivity testing was performed using VITEK 2 ID-GN and AST cards. Hypermucoviscosity was assessed using the string test, and an investigation into several adherence and virulence genes was conducted for all isolates. Then, multi-locus sequence typing was performed for hypermucoviscous K. pneumoniae isolates. Results: 3 (4.22%) of 71 isolates were hypermucoviscous. The virulence and adherence genes were present in 100% of the isolates, whereas rmpA was only found in hypermucoviscous isolates. The results showed that the hmKp isolates were members of clonal group 147 (CG147) and were assigned to sequence type (ST) 293. Conclusion: The string test is the primary phenotypical diagnosis for hmKp, while the genetically encoded rmpA gene is the most reliable genetic marker for hmKp identification. However, MLST is not beneficial for identification. The central positioning of ST392 within the MST highlights its potential role as an emerging high-risk clone. https://ijm.tums.ac.ir/index.php/ijm/article/view/5474 https://ijm.tums.ac.ir/index.php/ijm/article/download/5474/1819

Tehran University of Medical Sciences Iranian Journal of Microbiology 2008-3289 17 5 2025 10 14 741 750 Muhammad Shafiq Department of Biosciences, Comsats University, Islamabad, Pakistan Amnah Khan Department of Biosciences, Comsats University, Islamabad, Pakistan Muhammad Hyder Department of Biosciences, Comsats University, Islamabad, Pakistan Umme Farwa Department of Pathology, Fazaia Medical College, Air University, Islamabad, Pakistan Farhan Kursheed Department of Microbiology, PMAS Arid Agriculture University, Rawalpindi, Pakistan Sana Khan Department of Pathology, Pakistan Institute of Medical Sciences (PIMS), Islamabad, Pakistan Ayesha Siddiqa Department of Pathology, Pakistan Institute of Medical Sciences (PIMS), Islamabad, Pakistan Iftikhar Ahmed National Culture Collection of Pakistan (NCCP), Land Resources Research Institute (LRRI), National Agriculture Research Centre, Park Road, Islamabad, Pakistan Muhammad Saeed Department of Biosciences, Comsats University, Islamabad, Pakistan Muhammad Fiaz Department of Pathology, Pakistan Institute of Medical Sciences (PIMS), Islamabad, Pakistan 2024 12 25 2025 07 18 Background and Objectives: Global health is seriously threatened by the rise of carbapenem-resistant Enterobacterales (CRE). The blaNDM gene, a key carbapenemase coding gene, causes global health concern due to its multidrug resistance and easy spread through mobile genetic elements. This study aimed to identify and genetically characterize the blaNDM genes from uropathogens, its antibiotic susceptibility, and its correlation with global sequences. Materials and Methods: Urine samples were processed following microbiological guidelines. Isolates were identified using API-20E. Antibiotic susceptibility was tested using disc diffusion method, and bacterial DNAs were extracted for blaNDM gene sequencing for phylogenetic analysis. Results: CREs were detected in 11.92% (n=51) of the 428 Enterobacterales. Among CRE isolates, 45% (n=23) were positive for blaNDM gene harbored by Klebsiella pneumoniae (57%), followed by Escherichia coli (26%). Uropathogenic CRE, harboring blaNDM, revealed susceptibility of 34.78%, 60.87%, and 65.22% to amikacin, nitrofurantoin, and fosfomycin respectively. The blaNDM-5 variant was most common (69.57%), followed by blaNDM-1 (26.09%) and blaNDM-7 (4.35%). Phylogenetic analysis revealed that blaNDM variants exhibit diverse relationships with Pakistani and worldwide sequences. Conclusion: The significant presence of blaNDM in uropathogens, along with extensive antibiotic resistance, underscores the urgent need for continuous monitoring and antibiotic stewardship programs to manage the growing threat of CRE infections. https://ijm.tums.ac.ir/index.php/ijm/article/view/5216 https://ijm.tums.ac.ir/index.php/ijm/article/download/5216/1820

Tehran University of Medical Sciences Iranian Journal of Microbiology 2008-3289 17 5 2025 10 14 751 760 Amer Mustafa Department of Microbiology, General Directorate of Health Erbil, Ministry of Health, Erbil, Iraq 2025 03 02 2025 09 19 Background and Objectives: Urinary tract infections (UTIs) are common in pregnancy and can cause maternal and fetal complications. Proteus mirabilis is a significant pathogen in recurrent UTIs due to its virulence factors. This study investigated the virulence genes and antibiotic resistance patterns of P. mirabilis isolates from pregnant women with UTIs in Erbil, Iraq. Materials and Methods: This cross-sectional study (September 2024–January 2025) included 120 urine specimens from pregnant women (15-44 years) with UTI symptoms. Bacterial identification was performed using culture, biochemical tests, as well as the Vitek 2 system. Virulence genes were detected by PCR, and antimicrobial susceptibility was assessed by standard methods. Results: Of the 120 samples, 103 (85.8%) showed bacterial growth; 8 (6.7%) were positive for P. mirabilis, while 95 (79.1%) yielded other bacteria. The most affected age group was 25-34 years (52.5%), predominantly in the second trimester (42.5%) and urban residents (60.8%). Antimicrobial resistance was significant to ampicillin, trimethoprim-sulfamethoxazole, amoxicillin/clavulanic acid, and cephalosporins, although susceptibility was observed with several antibiotics. All P. mirabilis isolates harbored the UreC gene, and 75% possessed the MrpA virulence gene. Conclusion: Multidrug-resistant P. mirabilis with key virulence genes was detected in pregnant women with UTIs. Regular screening and resistance monitoring are essential for effective management. https://ijm.tums.ac.ir/index.php/ijm/article/view/5325 https://ijm.tums.ac.ir/index.php/ijm/article/download/5325/1821

Tehran University of Medical Sciences Iranian Journal of Microbiology 2008-3289 17 5 2025 10 14 761 772 Zeb Hussain Department of Microbiology, University of Karachi, Karachi, Pakistan; Department of Clinical Laboratory Sciences, Dow Institute of Medical Technology, Dow University of Health Sciences, Karachi, Pakistan Asma Naim Department of Microbiology, University of Karachi, Karachi, Pakistan Ambreen Fatima Department of Pathology, Dow International Medical College, Dow University of Health Sciences, Karachi, Pakistan Asad Karim Department of Molecular Medicine, Dr. Panjwani Center for Molecular Medicine and Drug Research, International Center for Chemical and Biological Sciences, University of Karachi, Karachi, Pakistan Fakhur Uddin Department of Microbiology, Basic Medical Sciences Institute (BMSI), Jinnah Postgraduate Medical Centre (JPMC), Karachi, Pakistan Surraya Shams Department of Clinical Laboratory Sciences, Dow Institute of Medical Technology, Dow University of Health Sciences, Karachi, Pakistan 2025 05 20 2025 08 25 Background and Objectives: Ventilator-associated pneumonia (VAP) caused by carbapenem-resistant Gram-negative bacteria is a serious ICU challenge. This study determined the prevalence, antimicrobial susceptibility profiles, and phenotypic carbapenemase resistance mechanisms of Gram-negative isolates from VAP patients in two tertiary hospitals in Karachi, Pakistan. Materials and Methods: We included 104 consecutive cases of VAP (July 2021–January 2023). A total of 67 carbapenem-resistant Gram-negative isolates were identified and tested. Antibiotic susceptibility was assessed by disk diffusion and broth micro dilution, according to CLSI and EUCAST guidelines. Modified and enhanced carbapenem inactivation methods (mCIM/eCIM) were used to distinguish metallo-β-lactamase (MBL) and serine carbapenemase production. Results: The mean age was 44.6 ± 18.3 years; 52.2% were male. Early-onset VAP accounted for 37.3% and late-onset for 62.7%. The most frequent pathogens were Acinetobacter baumannii (49.3%, 33/67) and Klebsiella pneumoniae (20.9%, 14/67). Notably, 67% of isolates produced MBLs, and 33% produced serine carbapenemases (phenotypically). The prevalence of multidrug-resistant (MDR), extensively drug-resistant (XDR), and pan drug-resistant (PDR) phenotypes was 42.6%, 31.3%, and 19.4%, respectively. Conclusion: VAP in our ICUs was dominated by A. baumannii and K. pneumoniae with high levels of MBL-mediated resistance. These findings highlight the urgent need for surveillance, stewardship, and new therapeutic options. https://ijm.tums.ac.ir/index.php/ijm/article/view/5505 https://ijm.tums.ac.ir/index.php/ijm/article/download/5505/1822

Tehran University of Medical Sciences Iranian Journal of Microbiology 2008-3289 17 5 2025 10 14 773 782 Azadeh Ehsani Department of Microbiology and Microbial Biotechnology, Faculty of Life Sciences and Biotechnology, Shahid Beheshti University, Tehran, Iran Neda Soleimani Department of Microbiology and Microbial Biotechnology, Faculty of Life Sciences and Biotechnology, Shahid Beheshti University, Tehran, Iran Mohammadreza Modaresi Estehbanati Department of Pediatric Pulmonary and Sleep Medicine, Children's Medical Center Hospital, Tehran University of Medical Sciences, Tehran, Iran 2024 12 01 2025 08 07 Background and Objectives: Pseudomonas aeruginosa is a Gram-negative bacterium that causes respiratory infections in individuals with cystic fibrosis. Its level of virulence is primarily controlled through Quorum Sensing (QS), a communication mechanism that utilizes small signaling molecules. This study investigates P. aeruginosa antibiotic resistance in CF patients in Imam Khomeini Hospital and examines the presence of QS genes in resistant strains. Materials and Methods: Sixty-five P. aeruginosa samples were identified in CF patients in Imam Khomeini Hospital in Tehran. Antibiotic resistance was assessed using the disk diffusion method, and QS genes (rhlI, rhlR, lasI, lasR) were evaluated by applying PCR. Results: Approximately 61.5 % of P. aeruginosa strains were multiple-drug-resistant (MDR), with 30.7% classified as extensively drug-resistant (XDR). The highest resistance was observed against amoxicillin, amikacin, and cefepime. The most common QS gene in MDR and XDR strains was rhlR. Additionally, 78.9% of XDR isolates carried rhlI, rhlR, lasI, and lasR genes. Conclusion: The study specified that more than half of the P. aeruginosa strains exhibited resistance to five antibiotic classes, and effective antibiotics against P. aeruginosa were colistin, meropenem, ciprofloxacin, piperacillin/tazobactam, and cefotaxime. A noteworthy correlation was identified between MDR and XDR strains and the existence of QS genes in the strains. https://ijm.tums.ac.ir/index.php/ijm/article/view/5169 https://ijm.tums.ac.ir/index.php/ijm/article/download/5169/1823

Tehran University of Medical Sciences Iranian Journal of Microbiology 2008-3289 17 5 2025 10 14 783 790 Farzaneh Zarei Mahmoodabadi Department of Biology, ET.C., Islamic Azad University, Tehran, Iran Akram Tabatabaee Bafroee Department of Biology, ET.C., Islamic Azad University, Tehran, Iran Arfa Moshiri Departments of Mycobacteriology and Pulmonary Research, Pasteur Institute of Iran, Tehran, Iran; Laboratory of Molecular Medicine, IRCCS Instituto Giannina Gaslini, Genova, Italy Seyed Davar Siadat Departments of Mycobacteriology and Pulmonary Research, Pasteur Institute of Iran, Tehran, Iran; Department of Biochemistry, Vanderbilt University Class of 2025, Microbiology Research Center (MRC), Pasteur Institute of Iran, Tehran, Iran Nayereh Ebrahimzadeh Departments of Mycobacteriology and Pulmonary Research, Pasteur Institute of Iran, Tehran, Iran 2025 04 28 2025 08 07 Background and Objectives: Breast tissue microbiota differs between healthy and cancerous tissues, with some bacteria influencing tumor progression. Staphylococcus epidermidis, a common skin commensal found in breast tumors, may play a role in epithelial-mesenchymal transition (EMT), a key step in metastasis. This study evaluated the effects of S. epidermidis culture and cell-free supernatant (CFS) on MDA-MB-231 breast cancer cell survival and expression of EMT-related genes Snail1, fibronectin 1 (FN1), and N-cadherin (CDH2). Materials and Methods: Different concentrations of S. epidermidis cultures and their CFS were applied to MDA-MB-231 cells. Cytotoxic effects were assessed by MTT assay at 2, 4, and 24 hours post-treatment. Real-time PCR analyzed gene expression after 24 hours of exposure to non-toxic concentrations (MOI 50 and 100 for cultures; 14% for CFS). Results: Low concentrations did not affect viability, while higher doses (MOI 100 and 14% CFS) reduced viability by up to 60% and 90%, respectively, at 24 hours. MOI 50 did not significantly alter gene expression. At MOI 100, Snail1 and FN1 were significantly upregulated, but CDH2 was unchanged. Treatment with 5% and 7% CFS significantly increased all three EMT gene expressions, indicating EMT induction. Conclusion: S. epidermidis affects EMT gene expression and cell viability, indicating potential involvement in breast cancer progression. https://ijm.tums.ac.ir/index.php/ijm/article/view/5468 https://ijm.tums.ac.ir/index.php/ijm/article/download/5468/1824

Tehran University of Medical Sciences Iranian Journal of Microbiology 2008-3289 17 5 2025 10 14 791 803 Nguyen Vinh Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, University of Health Sciences, Vietnam National University Ho Chi Minh City, Ho Chi Minh City, Vietnam; Department of Pharmaceutics, Research Center Of Discovery and Development Of Healthcare Products, Vietnam National University Ho Chi Minh City, Vietnam Nguyen Bac Department of Microbiology and Parasitology, School of Pharmacy, University of Medicine and Pharmacy at Ho Chi Minh City, Ho Chi Minh City, Vietnam Nguyen Thien Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, University of Health Sciences, Vietnam National University Ho Chi Minh City, Ho Chi Minh City, Vietnam Do Minh Department of Science, John F. Kennedy Catholic High School, Washington, U.S.A Dao Trung Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, University of Health Sciences, Vietnam National University Ho Chi Minh City, Ho Chi Minh City, Vietnam 2025 07 15 2025 09