Review
Microbiology
Alain Philippon, Guillaume Arlet, Roger Labia, Bogdan I. Iorga
Summary: Class C β-lactamases exhibit molecular variability and can be categorized into two functional groups. These enzymes are encoded by chromosomal and inducible genes and are widely distributed among bacteria. Molecular identification is based on three catalytic motifs, and numerous conserved amino acid residues have been identified. The concept of natural ESACs is supported by the discovery of genetic modifications in pathogenic species and the emergence of resistance to carbapenems and inhibitors.
CLINICAL MICROBIOLOGY REVIEWS
(2022)
Article
Microbiology
Jennifer M. Colquhoun, Marjan Farokhyfar, Anna R. Hutcheson, Alexander Anderson, Christopher R. Bethel, Robert A. Bonomo, Anthony J. Clarke, Philip N. Rather
Summary: Beta-lactamase expression is the main resistance mechanism in multidrug-resistant Acinetobacter baumannii, with high-level expression occurring in up to 98.5% of modern isolates. Overexpression of OXA-23 beta-lactamase leads to significant changes in peptidoglycan composition, creating new vulnerabilities and potentially novel antimicrobial targets. This study paves the way for new approaches to treating resistant A. baumannii strains.
Article
Microbiology
Julian Sommer, Kristina M. Gerbracht, Felix F. Krause, Florian Wild, Manuela Tietgen, Sara Riedel-Christ, Janko Sattler, Axel Hamprecht, Volkhard A. J. Kempf, Stephan Goettig
Summary: The study identified OXA-484 as a carbapenemase with high sequence similarity plasmids, showing low frequency in horizontal gene transfer. OXA-484 exhibits antibiotic activity between OXA-232 and OXA-244, demonstrating unique resistance characteristics.
FRONTIERS IN MICROBIOLOGY
(2021)
Article
Infectious Diseases
Maria Luisa Introvigne, Trevor J. J. Beardsley, Micah C. C. Fernando, David A. A. Leonard, Bradley J. J. Wallar, Susan D. D. Rudin, Magdalena A. A. Taracila, Philip N. N. Rather, Jennifer M. M. Colquhoun, Shaina Song, Francesco Fini, Kristine M. M. Hujer, Andrea M. M. Hujer, Fabio Prati, Rachel A. A. Powers, Robert A. A. Bonomo, Emilia Caselli
Summary: Acinetobacter baumannii is a Gram-negative organism that is listed as an urgent threat pathogen. The production of beta-lactamase enzymes is an important mechanism for carbapenem-resistant A. baumannii. CR167 was identified as a compound that can inhibit the beta-lactamases in A. baumannii.
Review
Infectious Diseases
Eun-Jeong Yoon, Seok Hoon Jeong
Summary: Class D beta-Lactamases consist of 14 families, with the majority belonging to the OXA family. These enzymes' genes are often identified in the chromosomes of environmental bacteria as intrinsic resistance determinants, and some are found in mobile genetic elements carried by clinically significant pathogens. The OXA family exhibits superheterogeneity, with diverse activity and substrate profiles determined by the active-site channel assembly.
JOURNAL OF ANTIMICROBIAL CHEMOTHERAPY
(2021)
Article
Infectious Diseases
Cristina Lasarte-Monterrubio, Juan C. Vazquez-Ucha, Maria Maneiro, Jorge Arca-Suarez, Isaac Alonso, Paula Guijarro-Sanchez, John D. Buynak, German Bou, Concepcion Gonzalez-Bello, Alejandro Beceiro
Summary: Combining LN-1-255 with imipenem, meropenem, cefepime, and sulbactam shows promising results in reducing resistance rates of Acinetobacter baumannii, especially carbapenem-resistant isolates, demonstrating a potential new strategy for the treatment of infections caused by this pathogen.
Article
Microbiology
Yunfei Dai, Victor Pinedo, Amy Y. Tang, Felipe Cava, Edward Geisinger
Summary: Acinetobacter baumannii lacks canonical enzymes for envelope construction and instead contains poorly annotated proteins, including ElsL, a novel cytoplasmic L,D-carboxypeptidase critical for cell wall recycling and integrity. Absence of ElsL weakens the cell envelope and impairs various cellular processes, highlighting its pleiotropic influence on envelope physiology. This discovery reveals an unappreciated mechanism of cell wall recycling, with implications for potential treatment strategies targeting bacterial envelopes.
Article
Infectious Diseases
Yung-Chih Wang, Shu-Wei Huang, Ming-Hsien Chiang, I-Ming Lee, Shu-Chen Kuo, Ya-Sung Yang, Chun-Hsiang Chiu, Ying-Shih Su, Te-Li Chen, Fu-Der Wang, Yi-Tzu Lee
Summary: The combination of imipenem and BLI-489 showed synergistic effects against CRAb isolates producing CHDLs, particularly OXA-24, OXA-51, and OXA-58. The results demonstrated significant inhibition and rescue effects on CRAb-infected experimental animals.
JOURNAL OF ANTIMICROBIAL CHEMOTHERAPY
(2021)
Article
Microbiology
Hongyan Luo, Dekang Zhu, Mengru Li, Yunhan Tang, Wenyu Zhang, Haoju Wang, Pei Li
Summary: Whole-genome sequencing of Riemerella anatipestifer isolate RCAD0122 identified a novel ESBL gene, bla(RAA-1), which encoded a class A extended-spectrum beta-lactamase with low sequence identity to known beta-lactamases. The purified RAA-1 showed ESBL-like hydrolysis activity, and the gene could be transferred to a homologous strain through natural transformation. However, epidemiological study revealed the gene is not currently prevalent.
ANTIMICROBIAL AGENTS AND CHEMOTHERAPY
(2022)
Article
Microbiology
Alessandra Piccirilli, Alberto Antonelli, Marco Maria D'Andrea, Sabrina Cherubini, Mariagrazia Perilli, Gian Maria Rossolini
Summary: The MOX lineage of beta-lactamases includes enzymes encoded by genes mobilized from the chromosomes of Aeromonas spp. to plasmids. MOX-9, a novel sublineage of MOX enzymes, shows a strong preference for cephalosporin substrates with some differences in biochemical characteristics compared to other MOX enzymes.
ANTIMICROBIAL AGENTS AND CHEMOTHERAPY
(2022)
Article
Chemistry, Physical
Vaishali Thakkur, Chandan Kumar Das, Nisanth N. Nair
Summary: The escalation of antibiotic resistance is a serious concern, particularly due to bacteria carrying class D beta-lactamases (DBLs). These enzymes can efficiently hydrolyze the last-reserved antibiotics for multidrug-resistant bacteria. This study investigates the inhibition mechanism of the OXA-48 DBL enzyme by the inhibitor avibactam through molecular dynamics simulations and free energy calculations. The findings provide insights into the reaction pathway and key intermediates, and reveal important chemical features for designing inhibitors, based on a comparison with the hydrolysis mechanism of meropenem.
Article
Medicine, General & Internal
Langamba A. Longjam, Dechen C. Tsering, Dipmala Das
Summary: This study characterizes resistance determinants responsible for multidrug-resistant (MDR) A. baumannii and emphasizes the use of genotyping in routine diagnosis. The most prevalent antibiotic resistance determinants among MDR A. baumannii were oxacillinase production corresponding to bla(OXA-23) and bla(OXA-51). Genotyping helps in understanding the association of isolates with encoded genes and designing effective surveillance and control strategies for MDR isolates.
CUREUS JOURNAL OF MEDICAL SCIENCE
(2023)
Article
Infectious Diseases
Mahnaz Nikibakhsh, Farzaneh Firoozeh, Farzad Badmasti, Kourosh Kabir, Mohammad Zibaei
Summary: The study detected a high prevalence of MBLs genes, especially bla(VIM), in multidrug-resistant A. baumannii isolates from burn patients. Most strains also carried class 1 integrons, and gene cassettes arrays of integrons including cmlA5 and cmlA7 were detected in Iran for the first time in A. baumannii.
BMC INFECTIOUS DISEASES
(2021)
Article
Biochemistry & Molecular Biology
Mohanraj Gopikrishnan, Sriroopreddy Ramireddy, Rinku Polachirakkal Varghese, Yamuna Devi Bakathavatchalam, D. Thirumal Kumar, Abi Manesh, Kamini Walia, Balaji Veeraraghavan, C. George Priya Doss
Summary: Carbapenem-resistant Acinetobacter baumannii is a common hospital-acquired pathogen with a high mortality rate. Combining beta-lactam antibiotics with beta-lactamase inhibitors can enhance their effectiveness. Through MIC testing and in silico analysis, we identified promising drug combinations, including eravacycline, cefepime/zidebactam, cefiderocol/zidebactam, and eravacycline with durlobactam or zidebactam, for treating A. baumannii infections expressing specific oxacillinases.
JOURNAL OF CELLULAR BIOCHEMISTRY
(2023)
Article
Microbiology
Marta Toth, Mijoon Lee, Nichole K. Stewart, Sergei B. Vakulenko
Summary: Resistance to beta-lactams is a major problem in treating bacterial infections. In the case of Acinetobacter baumannii, resistance to beta-lactam antibiotics has resulted in the spread of multidrug-resistant isolates. This study found that PBP3 is essential for the survival of A. baumannii, and inhibiting PBP1a and PBP2, or PBPs in combination with LdtJ, could be potential strategies for designing new drugs against this pathogen.
ANTIMICROBIAL AGENTS AND CHEMOTHERAPY
(2022)
Editorial Material
Infectious Diseases
Magne Bisgaard, Henrik Christensen, Dominique Clermont, Lenie Dijkshoorn, J. Michael Janda, Edward R. B. Moore, Alexandr Nemec, Niels Norskov-Lauritsen, Joerg Overmann, Frans A. G. Reubsaet
DIAGNOSTIC MICROBIOLOGY AND INFECTIOUS DISEASE
(2019)
Article
Biotechnology & Applied Microbiology
Jiayuan Qin, Martina Maixnerova, Matej Nemec, Yu Feng, Xinzhuo Zhang, Alexandr Nemec, Zhiyong Zong
SYSTEMATIC AND APPLIED MICROBIOLOGY
(2019)
Article
Food Science & Technology
Marta Mari-Almiralla, Clara Cosgaya, Maria J. Pons, Alexandr Nemec, Theresa J. Ochoa, Joaquim Ruiz, Ignasi Roca, Jordi Vila
INTERNATIONAL JOURNAL OF FOOD MICROBIOLOGY
(2019)
Article
Biochemistry & Molecular Biology
Roby P. Bhattacharyya, Nirmalya Bandyopadhyay, Peijun Ma, Sophie S. Son, Jamin Liu, Lorrie L. He, Lidan Wu, Rustem Khafizov, Rich Boykin, Gustavo C. Cerqueira, Alejandro Pironti, Robert F. Rudy, Milesh M. Patel, Rui Yang, Jennifer Skerry, Elizabeth Nazarian, Kimberly A. Musser, Jill Taylor, Virginia M. Pierce, Ashlee M. Earl, Lisa A. Cosimi, Noam Shoresh, Joseph Beechem, Jonathan Livny, Deborah T. Hung
Article
Oncology
Matthew Kyle Labriola, Jason Zhu, Rajan Gupta, Shannon McCall, Jennifer Jackson, Eric F. Kong, James R. White, Gustavo Cerqueira, Kelly Gerding, John K. Simmons, Daniel George, Tian Zhang
JOURNAL FOR IMMUNOTHERAPY OF CANCER
(2020)
Article
Biotechnology & Applied Microbiology
Alexandr Nemec, Lenka Radolfova-Krizova, Martina Maixnerova, Matej Nemec, Petra Spanelova, Renata Safrankova, Ondrej Sedo, Bruno S. Lopes, Paul G. Higgins
Summary: This study identified a novel group of 26 Acinetobacter strains (T24) forming a distinct clade within the genus based on core genome phylogenetic analysis. The strains exhibited differences in carbon source assimilation tests and led to the proposal of two new species, Acinetobacter terrae and Acinetobacter terrestris, associated with terrestrial ecosystems.
SYSTEMATIC AND APPLIED MICROBIOLOGY
(2021)
Article
Microbiology
Alexandr Nemec, Lenka Radolfova-Krizova, Martina Maixnerova, Violetta Shestivska, Petra Spanelova, Paul G. Higgins
Summary: This study investigated a taxonomically novel group within the genus Acinetobacter, finding that five strains exhibited unique characteristics in terms of genome sequences, strain features, and molecular mass spectra compared to known Acinetobacter species. As a result, these five strains represent a new environmental species, proposed to be named Acinetobacter silvestris sp. nov.
INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY
(2022)
Article
Microbiology
M. A. Cevallos, M. D. Basanta, E. Bello-Lopez, A. S. Escobedo-Munoz, F. M. Gonzalez-Serrano, A. Nemec, Y. J. Romero-Contreras, M. Serrano, E. A. Rebollar
Summary: This study isolated and characterized eight Acinetobacter bacteria from the skin of two tropical frog species. It was found that seven isolates had the ability to inhibit the growth of Batrachochytrium dendrobatidis (Bd), while all eight isolates inhibited the growth of the phytopathogen fungus Botrytis cinerea. The study suggests that the frog skin microbiome contains new species of Acinetobacter bacteria with broad antifungal functions.
FEMS MICROBIOLOGY ECOLOGY
(2022)
Article
Microbiology
Alexandr Nemec, Lenka Radolfova-Krizova, Martina Maixnerova, Matej Nemec, Violetta Shestivska, Petra Spanelova, Martina Kyselkova, Gottfried Wilharm, Paul G. Higgins
Summary: We studied a novel taxon of the genus Acinetobacter and identified its distinct characteristics through genome analysis and mass spectrometry. These novel strains have unique biological features that differentiate them from known Acinetobacter species. The taxon is widely distributed in various ecological and geographical environments.
INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY
(2022)
Article
Multidisciplinary Sciences
Duy Dinh Do Pham, Vera Jencova, Miriam Kanuchova, Jan Bayram, Ivana Grossova, Hubert Suca, Lukas Urban, Kristyna Havlickova, Vit Novotny, Petr Mikes, Viktor Mojr, Nikifor Asatiani, Eva Kuzelova Kosakova, Martina Maixnerova, Alena Vlkova, Dragana Vitovska, Hana Sanderova, Alexandr Nemec, Libor Krasny, Robert Zajicek, David Lukas, Dominik Rejman, Peter Gal
Summary: The study introduces a new concept of wound dressings based on polycaprolactone nanofiber scaffold (NANO) releasing lipophosphonoxin (LPPO) as an antibacterial agent to reduce bacterial load and promote skin repair, while maintaining proliferation and differentiation of fibroblasts and keratinocytes. The NANO-LPPO dressing demonstrated antibacterial activity in vitro and significantly reduced Staphylococcus aureus counts in infected wounds in a mouse model, with facilitated degradation and LPPO release by lytic enzymes secreted by bacteria. Negligible systemic absorption of LPPO was observed, suggesting the potential for clinical application in wound treatment.
SCIENTIFIC REPORTS
(2021)
Letter
Microbiology
Alexandr Nemec
Summary: A bacterial strain GC2 isolated from soil was proposed as a new species, Acinetobacter mesopotamicus. However, reanalysis revealed that GC2 actually belongs to A. lwoffii, contradicting the proposed classification. This misclassification is likely due to the use of an incorrect reference genome sequence in comparative analyses.
CURRENT MICROBIOLOGY
(2021)
Meeting Abstract
Medicine, Research & Experimental
Kelly Gerding, Kenneth Valkenburg, Christina Oliveras, James White, Leila Ettehadieh, Gustavo Cerqueira, Christopher Gault, James Hernandez, Eric Kong, Samuel Angiuoli, John Simmons, Isabell Loftin, Abigail McElhinny
LABORATORY INVESTIGATION
(2020)
Meeting Abstract
Pathology
Kelly Gerding, Kenneth Valkenburg, Christina Oliveras, James White, Leila Ettehadieh, Gustavo Cerqueira, Christopher Gault, James Hernandez, Eric Kong, Samuel Angiuoli, John Simmons, Isabell Loftin, Abigail McElhinny
Meeting Abstract
Oncology
Gustavo C. Cerqueira, Laurel A. Keefer, Donna Nichol, Julie R. Meyer, Nicholas C. Dracopoli
Meeting Abstract
Oncology
Sudhir Chowbina, Gustavo Cerqueira, Deacon Sweeney, Shantanu Shewale, James Hernandez, Eniko Papp, Mark Sausen, John Thompson, David Riley, Sam Angiuoli