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Detection of Genes Involved in Biofilm Formation in MDR and XDR Acinetobacter baumannii Isolated from Human Clinical Specimens in Isfahan, Iran. ARCHIVES OF CLINICAL INFECTIOUS DISEASES 2019. [DOI: 10.5812/archcid.85766] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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52
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Bravo Z, Orruño M, Navascues T, Ogayar E, Ramos-Vivas J, Kaberdin VR, Arana I. Analysis of Acinetobacter baumannii survival in liquid media and on solid matrices as well as effect of disinfectants. J Hosp Infect 2019; 103:e42-e52. [PMID: 30986481 DOI: 10.1016/j.jhin.2019.04.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Accepted: 04/07/2019] [Indexed: 12/18/2022]
Abstract
BACKGROUND Acinetobacter baumannii is a cause of healthcare-associated infections and has considerable potential to survive on inanimate hospital surfaces under hostile conditions (e.g. disinfection or desiccation). AIM To learn more about its survival strategy and capacity to persist in liquid media and on surfaces mimicking hospital environments. METHODS The effect of temperature, nutrient deprivation, permanence on inanimate surfaces, and exposure to disinfectants on the survival of four A. baumannii strains (ATCC 19606T and three clinical isolates) was studied by monitoring the number of total and viable cells using fluorescent microscopy and of culturable cells by standard cultures. FINDINGS Bacterial survival was differentially affected by temperature (cells maintained at 20°C remained culturable at least within 30 days) and physical environment (desiccation favoured cell resistance to stress at 37°C). Moreover, persistence was associated with two adaptation patterns: one linked to entry into the viable but non-culturable state, whereas the other apparently followed a bust-and-boom model. During a study on the effect of disinfectant (commercial bleach and quaternary ammonium compounds), it was found that treatment with these antibacterial compounds did not eliminate A. baumannii populations and provoked the reduction of culturable populations, although a fraction of cells remained culturable. CONCLUSION The ability to persist for long periods on different surfaces, mimicking those usually found in hospitals, along with A. baumannii's capacity to survive after a disinfection process may account for the recurrent outbreaks in intensive care units.
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Affiliation(s)
- Z Bravo
- Department of Immunology, Microbiology and Parasitology, Faculty of Science and Technology, University of the Basque Country (UPV/EHU), Leioa, Spain; Instituto de Investigación Valdecilla IDIVAL, Santander, Spain
| | - M Orruño
- Department of Immunology, Microbiology and Parasitology, Faculty of Science and Technology, University of the Basque Country (UPV/EHU), Leioa, Spain; Research Centre for Experimental Marine Biology and Biotechnology (PIE-UPV/EHU), Plentzia, Spain.
| | - T Navascues
- Department of Immunology, Microbiology and Parasitology, Faculty of Science and Technology, University of the Basque Country (UPV/EHU), Leioa, Spain; Instituto de Investigación Valdecilla IDIVAL, Santander, Spain
| | - E Ogayar
- Department of Immunology, Microbiology and Parasitology, Faculty of Science and Technology, University of the Basque Country (UPV/EHU), Leioa, Spain
| | - J Ramos-Vivas
- Instituto de Investigación Valdecilla IDIVAL, Santander, Spain
| | - V R Kaberdin
- Department of Immunology, Microbiology and Parasitology, Faculty of Science and Technology, University of the Basque Country (UPV/EHU), Leioa, Spain; Research Centre for Experimental Marine Biology and Biotechnology (PIE-UPV/EHU), Plentzia, Spain; Ikerbasque, Basque Foundation for Science, Bilbao, Spain
| | - I Arana
- Department of Immunology, Microbiology and Parasitology, Faculty of Science and Technology, University of the Basque Country (UPV/EHU), Leioa, Spain; Research Centre for Experimental Marine Biology and Biotechnology (PIE-UPV/EHU), Plentzia, Spain
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53
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Abstract
Acinetobacter baumannii and other Acinetobacter spp. display biofilm formation on abiotic surfaces. The degree of biofilm formation varies considerably depending on the isolates. While culturing, bacteria tend to attach to abiotic surfaces, and some surfaces perform better than others. Numerous methods are available to study in vitro biofilm formation by bacteria under static growth, and they basically rely upon culturing the bacteria in an ampule followed by staining the bacterial growth attached to the abiotic surface with a suitable dye such as crystal violet to visualize the biofilm. Subsequently, the dye is eluted with a suitable solvent, and optical density is measured to quantify the attached bacterial mass. In this chapter, we provide a basic and simple yet a powerful method to study biofilm formation by A. baumannii grown under static conditions.
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Affiliation(s)
- Indranil Biswas
- Department of Microbiology, Molecular Genetics and Immunology, University of Kansas Medical Center, Kansas City, KS, USA.
| | - Joshua Mettlach
- Department of Microbiology, Molecular Genetics and Immunology, University of Kansas Medical Center, Kansas City, KS, USA
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54
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Ranin J, Šmitran A, Gajić I. Biofilm production and twitching and swarming motility of clinical isolates Acinetobacter baumannii. MEDICINSKI PODMLADAK 2019. [DOI: 10.5937/mp70-17903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
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55
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Abstract
Bacteria belonging to genus Acinetobacter do not encode flagella and are characterized as a non-motile organism. However, several recent studies have demonstrated that Acinetobacter spp. display two types of motility: twitching and swarming. Twitching motility requires the presence of functional type IV pili and occurs on solid surfaces under humid conditions. The extension and the retraction of the pili allows the bacterium to move and spread. In contrast the exact molecular mechanism for swarming motility in Acinetobacter spp. is currently unknown; but it requires semisolid surfaces and humid conditions. Motility has been associated with the bacterial virulence; however, motility appears to be highly dependent on the experimental conditions and the isolate understudy. In this chapter we attempt to provide detailed methods for twitching and swarming motilities that are specific for Acinetobacter spp.
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56
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Fernandez-Garcia L, Ambroa A, Blasco L, Bleriot I, López M, Alvarez-Marin R, Fernández-Cuenca F, Martinez-Martinez L, Vila J, Rodríguez-Baño J, Garnacho-Montero J, Cisneros JM, Pascual A, Pachón J, Bou G, Smani Y, Tomás M. Relationship Between the Quorum Network (Sensing/Quenching) and Clinical Features of Pneumonia and Bacteraemia Caused by A. baumannii. Front Microbiol 2018; 9:3105. [PMID: 30619184 PMCID: PMC6304438 DOI: 10.3389/fmicb.2018.03105] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2018] [Accepted: 11/30/2018] [Indexed: 01/22/2023] Open
Abstract
Acinetobacter baumannii (Ab) is one of the most important pathogens associated with nosocomial infections, especially pneumonia. Interest in the Quorum network, i.e., Quorum Sensing (QS)/Quorum Quenching (QQ), in this pathogen has grown in recent years. The Quorum network plays an important role in regulating diverse virulence factors such as surface motility and bacterial competition through the type VI secretion system (T6SS), which is associated with bacterial invasiveness. In the present study, we investigated 30 clinical strains of A. baumannii isolated in the “II Spanish Study of A. baumannii GEIH-REIPI 2000-2010” (Genbank Umbrella Bioproject PRJNA422585), a multicentre study describing the relationship between the Quorum network in A. baumannii and the development of pneumonia and associated bacteraemia. Expression of the aidA gene (encoding the AidA protein, QQ enzyme) was lower (P < 0.001) in strains of A. baumannii isolated from patients with bacteraemic pneumonia than in strains isolated from patients with non-bacteraemic pneumonia. Moreover, aidA expression in the first type of strain was not regulated in the presence of environmental stress factors such as the 3-oxo-C12-HSL molecule (substrate of AidA protein, QQ activation) or H2O2 (inhibitor of AidA protein, QS activation). However, in the A. baumannii strains isolated from patients with non-bacteraemic pneumonia, aidA gene expression was regulated by stressors such as 3-oxo-C12-HSL and H2O2. In an in vivo Galleria mellonella model of A. baumannii infection, the A. baumannii ATCC 17978 strain was associated with higher mortality (100% at 24 h) than the mutant, abaI-deficient, strain (carrying a synthetase enzyme of Acyl homoserine lactone molecules) (70% at 24 h). These data suggest that the QS (abaR and abaI genes)/QQ (aidA gene) network affects the development of secondary bacteraemia in pneumonia patients and also the virulence of A. baumannii.
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Affiliation(s)
- Laura Fernandez-Garcia
- Microbiology Department-Biomedical Research Institute A Coruña (INIBIC), Hospital A Coruña (CHUAC), University of A Coruña (UDC), A Coruña, Spain
| | - Antón Ambroa
- Microbiology Department-Biomedical Research Institute A Coruña (INIBIC), Hospital A Coruña (CHUAC), University of A Coruña (UDC), A Coruña, Spain
| | - Lucia Blasco
- Microbiology Department-Biomedical Research Institute A Coruña (INIBIC), Hospital A Coruña (CHUAC), University of A Coruña (UDC), A Coruña, Spain
| | - Ines Bleriot
- Microbiology Department-Biomedical Research Institute A Coruña (INIBIC), Hospital A Coruña (CHUAC), University of A Coruña (UDC), A Coruña, Spain
| | - Maria López
- Microbiology Department-Biomedical Research Institute A Coruña (INIBIC), Hospital A Coruña (CHUAC), University of A Coruña (UDC), A Coruña, Spain
| | - Rocio Alvarez-Marin
- Clinical Unit for Infectious Diseases, Microbiology and Preventive Medicine, Institute of Biomedicine of Seville (IBIS), University Hospital Virgen del Rocío/CSIC/University Seville, Seville, Spain
| | - Felipe Fernández-Cuenca
- Clinical Unit for Infectious Diseases, Microbiology and Preventive Medicine, Department of Microbiology and Medicine, Biomedicine Institute of Seville, Hospital Universitario Virgen Macarena, University of Seville, Seville, Spain
| | - Luis Martinez-Martinez
- Unit of Microbiology, Department of Microbiology, Maimonides Biomedical Research Institute of Cordoba, University Hospital Reina Sofía, University of Córdoba, Córdoba, Spain
| | - Jordi Vila
- Institute of Global Health of Barcelona (ISGlobal), Hospital Clínic - Universitat de Barcelona, Barcelona, Spain
| | - Jesús Rodríguez-Baño
- Clinical Unit for Infectious Diseases, Microbiology and Preventive Medicine, Department of Microbiology and Medicine, Biomedicine Institute of Seville, Hospital Universitario Virgen Macarena, University of Seville, Seville, Spain
| | - Jose Garnacho-Montero
- Intensive Care Clinical Unit-Institute of Biomedicine of Seville (IBIS), Hospital Virgen Macarena, Seville, Spain
| | - Jose Miguel Cisneros
- Clinical Unit for Infectious Diseases, Microbiology and Preventive Medicine, Institute of Biomedicine of Seville (IBIS), University Hospital Virgen del Rocío/CSIC/University Seville, Seville, Spain
| | - Alvaro Pascual
- Clinical Unit for Infectious Diseases, Microbiology and Preventive Medicine, Department of Microbiology and Medicine, Biomedicine Institute of Seville, Hospital Universitario Virgen Macarena, University of Seville, Seville, Spain
| | - Jeronimo Pachón
- Clinical Unit for Infectious Diseases, Microbiology and Preventive Medicine, Institute of Biomedicine of Seville (IBIS), University Hospital Virgen del Rocío/CSIC/University Seville, Seville, Spain.,Department of Medicine, University of Seville, Seville, Spain
| | - German Bou
- Microbiology Department-Biomedical Research Institute A Coruña (INIBIC), Hospital A Coruña (CHUAC), University of A Coruña (UDC), A Coruña, Spain
| | - Younes Smani
- Clinical Unit for Infectious Diseases, Microbiology and Preventive Medicine, Institute of Biomedicine of Seville (IBIS), University Hospital Virgen del Rocío/CSIC/University Seville, Seville, Spain
| | - Maria Tomás
- Microbiology Department-Biomedical Research Institute A Coruña (INIBIC), Hospital A Coruña (CHUAC), University of A Coruña (UDC), A Coruña, Spain
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Ronish LA, Lillehoj E, Fields JK, Sundberg EJ, Piepenbrink KH. The structure of PilA from Acinetobacter baumannii AB5075 suggests a mechanism for functional specialization in Acinetobacter type IV pili. J Biol Chem 2018; 294:218-230. [PMID: 30413536 DOI: 10.1074/jbc.ra118.005814] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Revised: 10/19/2018] [Indexed: 11/06/2022] Open
Abstract
Type IV pili (T4P) are bacterial appendages composed of protein subunits, called pilins, noncovalently assembled into helical fibers. T4P are essential, in many bacterial species, for processes as diverse as twitching motility, natural competence, biofilm or microcolony formation, and host cell adhesion. The genes encoding type IV pili are found universally in the Gram-negative, aerobic, nonflagellated, and pathogenic coccobacillus Acinetobacter baumannii, but there is considerable variation in PilA, the major protein subunit, both in amino acid sequence and in glycosylation patterns. Here we report the X-ray crystal structure of PilA from AB5075, a recently characterized, highly virulent isolate, at 1.9 Å resolution and compare it to homologues from A. baumannii strains ACICU and BIDMC57, which are C-terminally glycosylated. These structural comparisons revealed that PilAAB5075 exhibits a distinctly electronegative surface chemistry. To understand the functional consequences of this change in surface electrostatics, we complemented a ΔpilA knockout strain with divergent pilA genes from ACICU, BIDMC57, and AB5075. The resulting transgenic strains showed differential twitching motility and biofilm formation while maintaining the ability to adhere to epithelial cells. PilAAB5075 and PilAACICU, although structurally similar, promote different characteristics, favoring twitching motility and biofilm formation, respectively. These results support a model in which differences in pilus electrostatics affect the equilibrium of microcolony formation, which in turn alters the balance between motility and biofilm formation in Acinetobacter.
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Affiliation(s)
- Leslie A Ronish
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, Nebraska 68588
| | - Erik Lillehoj
- Department of Pediatrics, University of Maryland School of Medicine, Baltimore, Maryland 21201
| | - James K Fields
- Institute of Human Virology, University of Maryland School of Medicine, Baltimore, Maryland 21201
| | - Eric J Sundberg
- Institute of Human Virology, University of Maryland School of Medicine, Baltimore, Maryland 21201; Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland 21201; Departments of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland 21201
| | - Kurt H Piepenbrink
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, Nebraska 68588; Departments of Food Science and Technology, University of Nebraska-Lincoln, Lincoln, Nebraska 68588; Nebraska Food for Health Center, University of Nebraska-Lincoln, Lincoln, Nebraska 68588; Center for Integrated Biomolecular Communication, University of Nebraska-Lincoln, Lincoln, Nebraska 68588.
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58
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Carretero-Ledesma M, García-Quintanilla M, Martín-Peña R, Pulido MR, Pachón J, McConnell MJ. Phenotypic changes associated with Colistin resistance due to Lipopolysaccharide loss in Acinetobacter baumannii. Virulence 2018; 9:930-942. [PMID: 29638177 PMCID: PMC5955468 DOI: 10.1080/21505594.2018.1460187] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Acinetobacter baumannii can acquire resistance to colistin via complete loss of lipopolysaccharide (LPS) biosynthesis due to mutations in the lpxA, lpxC and lpxD genes. However, although colistin is increasingly being used for the treatment of multidrug resistant infections, very few A. baumannii clinical isolates develop colistin resistance through loss of LPS biosynthesis. This may suggest that LPS loss affects virulence traits that play a role in the transmission and pathogenesis of A. baumannii. In this study we characterize multiple virulence phenotypes of colistin resistant, LPS-deficient derivatives of the ATCC 19606 strain and five multidrug resistant clinical isolates and their colistin resistant, LPS-deficient derivatives. Our results indicate that LPS loss results in growth defects compared to the parental strain in vitro both in laboratory media and human serum (competition indices of 0.58 and 7.0 × 10−7, respectively) and reduced ability to grow and disseminate in vivo (competition index 6.7 × 10−8). Infection with the LPS-deficient strain resulted in lower serum levels of pro-inflammatory cytokines TNF-α and IL-6 compared to the parent strain, and was less virulent in a mouse model of disseminated sepsis. LPS loss also significantly affected biofilm production, surface motility, growth under iron limitation and susceptibility to multiple disinfectants used in the clinical setting. These results demonstrate that LPS loss has a significant effect on multiple virulence traits, and may provide insight into the low incidence of colistin resistant strains lacking LPS that have been reported in the clinical setting.
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Affiliation(s)
- Marta Carretero-Ledesma
- a Clinical Unit of Infectious Diseases, Clinical Microbiology and Preventive Medicine; Institute of Biomedicine of Seville (IBiS), University Hospital Virgen del Rocío/CSIC /University of Seville , Seville , Spain
| | - Meritxell García-Quintanilla
- a Clinical Unit of Infectious Diseases, Clinical Microbiology and Preventive Medicine; Institute of Biomedicine of Seville (IBiS), University Hospital Virgen del Rocío/CSIC /University of Seville , Seville , Spain
| | - Reyes Martín-Peña
- a Clinical Unit of Infectious Diseases, Clinical Microbiology and Preventive Medicine; Institute of Biomedicine of Seville (IBiS), University Hospital Virgen del Rocío/CSIC /University of Seville , Seville , Spain
| | - Marina R Pulido
- a Clinical Unit of Infectious Diseases, Clinical Microbiology and Preventive Medicine; Institute of Biomedicine of Seville (IBiS), University Hospital Virgen del Rocío/CSIC /University of Seville , Seville , Spain
| | - Jerónimo Pachón
- a Clinical Unit of Infectious Diseases, Clinical Microbiology and Preventive Medicine; Institute of Biomedicine of Seville (IBiS), University Hospital Virgen del Rocío/CSIC /University of Seville , Seville , Spain.,b Department of Medicine , University of Seville , Seville , Spain
| | - Michael J McConnell
- a Clinical Unit of Infectious Diseases, Clinical Microbiology and Preventive Medicine; Institute of Biomedicine of Seville (IBiS), University Hospital Virgen del Rocío/CSIC /University of Seville , Seville , Spain
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59
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Correlation of Virulence Factors and Cell Adhesion of Clinical Isolates of Acinetobacter baumannii. ARCHIVES OF CLINICAL INFECTIOUS DISEASES 2018. [DOI: 10.5812/archcid.62841] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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60
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Phenotypic and Genotypic Investigation of Biofilm Formation in Clinical and Environmental Isolates of Acinetobacter baumannii. ARCHIVES OF CLINICAL INFECTIOUS DISEASES 2018. [DOI: 10.5812/archcid.12914] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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61
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Harding CM, Hennon SW, Feldman MF. Uncovering the mechanisms of Acinetobacter baumannii virulence. Nat Rev Microbiol 2017; 16:91-102. [PMID: 29249812 DOI: 10.1038/nrmicro.2017.148] [Citation(s) in RCA: 547] [Impact Index Per Article: 78.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Acinetobacter baumannii is a nosocomial pathogen that causes ventilator-associated as well as bloodstream infections in critically ill patients, and the spread of multidrug-resistant Acinetobacter strains is cause for concern. Much of the success of A. baumannii can be directly attributed to its plastic genome, which rapidly mutates when faced with adversity and stress. However, fundamental virulence mechanisms beyond canonical drug resistance were recently uncovered that enable A. baumannii and, to a limited extent, other medically relevant Acinetobacter species to successfully thrive in the health-care environment. In this Review, we explore the molecular features that promote environmental persistence, including desiccation resistance, biofilm formation and motility, and we discuss the most recently identified virulence factors, such as secretion systems, surface glycoconjugates and micronutrient acquisition systems that collectively enable these pathogens to successfully infect their hosts.
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Affiliation(s)
- Christian M Harding
- Department of Molecular Microbiology, Washington University School of Medicine in St. Louis, St. Louis, Missouri 63110, USA.,VaxNewMo LLC, St. Louis, Missouri 63108, USA
| | - Seth W Hennon
- Department of Molecular Microbiology, Washington University School of Medicine in St. Louis, St. Louis, Missouri 63110, USA
| | - Mario F Feldman
- Department of Molecular Microbiology, Washington University School of Medicine in St. Louis, St. Louis, Missouri 63110, USA.,VaxNewMo LLC, St. Louis, Missouri 63108, USA
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62
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Ambrosi C, Scribano D, Aleandri M, Zagaglia C, Di Francesco L, Putignani L, Palamara AT. Acinetobacter baumannii Virulence Traits: A Comparative Study of a Novel Sequence Type with Other Italian Endemic International Clones. Front Microbiol 2017; 8:1977. [PMID: 29075243 PMCID: PMC5643476 DOI: 10.3389/fmicb.2017.01977] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 09/25/2017] [Indexed: 01/20/2023] Open
Abstract
Carbapenem-resistant Acinetobacter baumannii (CRAb) have emerged in recent decades as major causes of nosocomial infections. Resistance is mainly due to overexpression of intrinsic and/or acquired carbapenemases, especially oxacillinases (OXA). In Italy, although the sequence type (ST) 2 and the ST78 are the most frequently detected, we recently reported ST632, a single locus variant of ST2. Therefore, this study was aimed at unraveling common bacterial surface virulence factors involved in pathogenesis and antibiotic resistance in representative CRAb of these ST genotypes. Outer membrane protein (OMP) composition together with motility, biofilm formation, in vitro adherence to, invasion of, and survival within pneumocytes were analyzed. Differently from the carbapenem-susceptible reference strain ATCC 17978, either overexpressed OXA-51 or both OXA-23 and OXA-51 co-purified with OMPs in CRAb. This tight association ensures their maximal concentration on the inner surface of the outer membrane to provide the best protection against carbapenems. These findings led us to propose for the first time a common behavior of OXA enzymes in CRAb. Despite the presence of both OmpA and phosphorylcholine-porinD and the ability of all the strains to adhere to cells, invasion, and survival within pneumocytes was shown only by ST2 and ST78 isolates, sharing the highest number of identified OMPs. Conversely, notwithstanding genetic and OMPs similarities with ST2, ST632 was unable to invade and survive within epithelial cells. Overall, our study shows that different STs share a specific OMP composition, also shaped by overexpressed OXA, that is needed for invasiveness and survival of CRAb.
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Affiliation(s)
- Cecilia Ambrosi
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy.,Dani Di Giò Foundation-Onlus, Rome, Italy
| | - Daniela Scribano
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy.,Department of Medical, Oral and Biotechnological Sciences, Università degli Studi "G. d'Annunzio" Chieti-Pescara, Chieti, Italy
| | - Marta Aleandri
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy
| | - Carlo Zagaglia
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy
| | - Laura Di Francesco
- Unit of Human Microbiome, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Lorenza Putignani
- Unit of Human Microbiome, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy.,Unit of Parasitology, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Anna Teresa Palamara
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Laboratory Affiliated to Institute Pasteur Italia, Cenci-Bolognetti Foundation, Rome, Italy.,San Raffaele Pisana, IRCCS, Telematic University, Rome, Italy
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63
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Bogdan M, Drenjancevic D, Harsanji Drenjancevic I, Bedenic B, Zujic Atalic V, Talapko J, Vukovic D. In vitro effect of subminimal inhibitory concentrations of antibiotics on the biofilm formation ability of Acinetobacter baumannii clinical isolates. J Chemother 2017; 30:16-24. [PMID: 28956494 DOI: 10.1080/1120009x.2017.1378835] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The ability of A cinetobacter baumannii strains to form biofilm is one of the most important virulence factor which enables bacterial survival in a harsh environment and decreases antibiotic concentration as well. Subminimal inhibitory concentrations (subMICs) of antibiotics may change bacterial ultrastructure or have an influence on some different molecular mechanisms resulting in morphological or physiological changes in bacteria itself. The aim of this study was to determine effects of 1/2, 1/4, 1/8 and 1/16 minimal inhibitory concentrationsof imipenem, ampicillin-sulbactam, azithromycin, rifampicin and colistin on biofilm formation ability of 22 biofilm non-producing and 46 biofilm producing A. baumannii strains (30 weak producing strains and 16 moderate producing strains). Results of this study indicate that 1/2-1/16 MICs of imipenem, azithromycin, and rifampicin can reduce bacterial biofilm formation ability in moderate producing strains (p < 0.05), whereas 1/16 MIC of imipenem and 1/4-1/8 MICs of rifampicin reduce the biofilm formation in weak producing strains (p < 0.05). Statisticaly significant effect was detected among biofilm non-producing strains after their exposure to 1/16 MIC of azithromycin (p = 0.039). SubMICs of ampicillin-sulbactam and colistin did not have any significant effect on biofilm formation among tested A. baumannii strains.
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Affiliation(s)
- Maja Bogdan
- a Microbiology Service , Institute of Public Health Osijek-Baranja County , Osijek , Croatia.,b Faculty of Medicine, Department of Microbiology and Parasitology , University of Osijek , Osijek , Croatia
| | - Domagoj Drenjancevic
- b Faculty of Medicine, Department of Microbiology and Parasitology , University of Osijek , Osijek , Croatia.,c Department of Transfusion Medicine , Osijek University Hospital , Osijek , Croatia
| | - Ivana Harsanji Drenjancevic
- d Department of Anesthesiology, Reanimatology and Intensive Medicine , Osijek University Hospital , Osijek , Croatia.,e Faculty of Medicine, Department of Anesthesiology, Reanimatology and Intensive Medicine , University of Osijek , Osijek , Croatia
| | - Branka Bedenic
- f Department of Clinical and Molecular Microbiology , University Hospital Center Zagreb , Zagreb , Croatia.,g Department of Microbiology and Parasitology , School of Medicine, University of Zagreb , Zagreb , Croatia
| | - Vlasta Zujic Atalic
- a Microbiology Service , Institute of Public Health Osijek-Baranja County , Osijek , Croatia.,b Faculty of Medicine, Department of Microbiology and Parasitology , University of Osijek , Osijek , Croatia
| | - Jasminka Talapko
- b Faculty of Medicine, Department of Microbiology and Parasitology , University of Osijek , Osijek , Croatia
| | - Dubravka Vukovic
- a Microbiology Service , Institute of Public Health Osijek-Baranja County , Osijek , Croatia
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64
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Chen R, Lv R, Xiao L, Wang M, Du Z, Tan Y, Cui Y, Yan Y, Luo Y, Yang R, Song Y. A1S_2811, a CheA/Y-like hybrid two-component regulator from Acinetobacter baumannii ATCC17978, is involved in surface motility and biofilm formation in this bacterium. Microbiologyopen 2017; 6. [PMID: 28714256 PMCID: PMC5635159 DOI: 10.1002/mbo3.510] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Revised: 05/22/2017] [Accepted: 05/25/2017] [Indexed: 12/14/2022] Open
Abstract
Two‐component systems in Acinetobacter baumannii are associated with its virulence, drug resistance, motility, biofilm formation, and other characteristics. In this study, we used RecAb, a genetic engineering method, to investigate the function of A1S_2811 in A. baumannii strain ATCC17978. A1S_2811, a hypothetical hybrid sensor histidine kinase/response regulator, has four histidine‐containing phosphotransfer domains, a CheA‐like regulatory domain, and a CheY‐like receiver domain at its C terminus. Compared with the ATCC17978 strain, both surface motility and biofilm formation at the gas–liquid interface decreased significantly in the A1S_2811 knock‐out strain. The number of pilus‐like structures and the amount of extrapolymeric substances on the cell surface also decreased in the A1S_2811 null strain. Transcription of abaI, which encodes an N‐acylhomoserine lactone synthase in A. baumannii , decreased significantly in the A1S_2811 null strain, and supplementation with synthetic N‐(3‐oxodecanoyl) homoserine‐l‐lactone rescued the surface motility and biofilm formation phenotype in the null mutant. We speculate that A1S_2811 regulates surface motility and biofilm formation, not by regulating type IV pili‐associated genes expression, but by regulating the chaperone/usher pili‐associated csuA/ABCDE operon and the AbaI‐dependent quorum‐sensing pathway‐associated A1S_0112‐0119 operon instead.
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Affiliation(s)
- Rong Chen
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China.,Department of Clinical Microbiology, General Hospital of Chinese People's Liberation Army, Beijing, China
| | - Ruichen Lv
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Lisheng Xiao
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Min Wang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Zongmin Du
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Yafang Tan
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Yujun Cui
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Yanfeng Yan
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Yanping Luo
- Department of Clinical Microbiology, General Hospital of Chinese People's Liberation Army, Beijing, China
| | - Ruifu Yang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Yajun Song
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
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Bardbari AM, Arabestani MR, Karami M, Keramat F, Alikhani MY, Bagheri KP. Correlation between ability of biofilm formation with their responsible genes and MDR patterns in clinical and environmental Acinetobacter baumannii isolates. Microb Pathog 2017; 108:122-128. [PMID: 28457900 DOI: 10.1016/j.micpath.2017.04.039] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Revised: 04/26/2017] [Accepted: 04/26/2017] [Indexed: 10/19/2022]
Abstract
Acinetobacter baumannii potential to form biofilm and exhibit multiple antibiotic resistances may be responsible in its survival in hospital environment. Accordingly, our study was aimed to determine the correlation between ability of biofilm formation and the frequency of biofilm related genes with antibiotic resistance phenotypes, and also the categorization of their patterns in clinical and environmental isolates. A total of 75 clinical and 32 environmental strains of the A. baumannii were collected and identified via API 20NE. Antibiotic susceptibility was evaluated by disk diffusion and microdilution broth methods. Biofilm formation assay was performed by microtiter plate method. OXA types and biofilm related genes including BlaOXA-51, BlaOXA-23, BlaOXA-24, BlaOXA-58, bap, blaPER-1, and ompA were amplified by PCR. The rate of MDR A. baumannii in clinical isolates (100%) was higher than environmental (81.2%) isolates (p < 0.05). Among 10 antibiotypes, the predominant resistance pattern in clinical and environmental isolates was antibiotypes I (85.3 and 78.1%, respectively). Analysis of the frequency of blaOXA-23 gene revealed a statistically significant difference between clinical (85.3%) and environmental (68.7%) isolates (p < 0.05). The prevalence of strong biofilm producers in clinical and environmental isolates were 31.2%-58.7%, respectively. In the clinical and environmental isolates, the frequencies of ompA, blaRER-1 and bap genes were 100%, 53.3%, 82.7% and 100%, 37.5%, 84.4% respectively. Statistical analysis revealed a significant correlation between the frequency of MDR isolates and biofilm formation ability (p = 0.008). The high frequency of antibiotype I would be indicated that an outbreak has been happened earlier and an endemic strain is currently being settled in the hospital environment. It would be suggested that if there was no difference in the frequency of pattern I and biofilm formation ability between clinical and environmental isolates, it is a critical point representing the higher risk of bacterial transmission from environment to the patients. The resulting data would be assisted in the improvement of disinfection strategies to better control of nosocomial infections. One dominant resistance pattern has shown among clinical and environmental isolates. The frequency of blaOXA-23 had significant difference between clinical and environmental isolates. The presence of bap gene in the A. baumannii isolates was associated with biofilm formation. There was a significant correlation between multiple drug resistance and biofilm formation. The clinical isolates had a higher ability to form strong biofilms compared to the environmental samples.
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Affiliation(s)
- Ali Mohammadi Bardbari
- Department of Microbiology, Faculty of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran.
| | - Mohammad Reza Arabestani
- Department of Microbiology, Faculty of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran.
| | - Manoochehr Karami
- Department of Epidemiology, School of Public Health, Hamadan University of Medical Sciences, Hamadan, Iran.
| | - Fariba Keramat
- Department of Infectious Diseases, Faculty of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran; Brucellosis Research Center, Hamadan University of Medical Sciences, Hamadan, Iran.
| | - Mohammad Yousef Alikhani
- Department of Microbiology, Faculty of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran; Brucellosis Research Center, Hamadan University of Medical Sciences, Hamadan, Iran.
| | - Kamran Pooshang Bagheri
- Venom and Biotherapeutics Molecules Lab., Medical Biotechnology Dept., Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran.
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López M, Mayer C, Fernández-García L, Blasco L, Muras A, Ruiz FM, Bou G, Otero A, Tomás M. Quorum sensing network in clinical strains of A. baumannii: AidA is a new quorum quenching enzyme. PLoS One 2017; 12:e0174454. [PMID: 28328989 PMCID: PMC5362224 DOI: 10.1371/journal.pone.0174454] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Accepted: 03/09/2017] [Indexed: 12/12/2022] Open
Abstract
Acinetobacter baumannii is an important pathogen that causes nosocomial infections generally associated with high mortality and morbidity in Intensive Care Units (ICUs). Currently, little is known about the Quorum Sensing (QS)/Quorum Quenching (QQ) systems of this pathogen. We analyzed these mechanisms in seven clinical isolates of A. baumannii. Microarray analysis of one of these clinical isolates, Ab1 (A. baumannii ST-2_clon_2010), previously cultured in the presence of 3-oxo-C12-HSL (a QS signalling molecule) revealed a putative QQ enzyme (α/ß hydrolase gene, AidA). This QQ enzyme was present in all non-motile clinical isolates (67% of which were isolated from the respiratory tract) cultured in nutrient depleted LB medium. Interestingly, this gene was not located in the genome of the only motile clinical strain growing in this medium (A. baumannii strain Ab421_GEIH-2010 [Ab7], isolated from a blood sample). The AidA protein expressed in E. coli showed QQ activity. Finally, we observed downregulation of the AidA protein (QQ system attenuation) in the presence of H2O2 (ROS stress). In conclusion, most of the A. baumannii clinical strains were not surface motile (84%) and were of respiratory origin (67%). Only the pilT gene was involved in surface motility and related to the QS system. Finally, a new QQ enzyme (α/ß hydrolase gene, AidA protein) was detected in these strains.
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Affiliation(s)
- María López
- Department of Microbiology, Complejo Hospitalario Universitario A Coruña (CHUAC)-INIBIC, A Coruña, Spain
- Spanish Network for Research in Infectious Diseases (REIPI), Virgen Macarena, Seville, Spain
| | - Celia Mayer
- Department of Microbiology, Faculty of Biology-CIBUS, University of Santiago de Compostela, Santiago de Compostela, Spain
| | - Laura Fernández-García
- Department of Microbiology, Complejo Hospitalario Universitario A Coruña (CHUAC)-INIBIC, A Coruña, Spain
| | - Lucía Blasco
- Department of Microbiology, Complejo Hospitalario Universitario A Coruña (CHUAC)-INIBIC, A Coruña, Spain
| | - Andrea Muras
- Department of Microbiology, Faculty of Biology-CIBUS, University of Santiago de Compostela, Santiago de Compostela, Spain
| | | | - German Bou
- Department of Microbiology, Complejo Hospitalario Universitario A Coruña (CHUAC)-INIBIC, A Coruña, Spain
- Spanish Network for Research in Infectious Diseases (REIPI), Virgen Macarena, Seville, Spain
| | - Ana Otero
- Department of Microbiology, Faculty of Biology-CIBUS, University of Santiago de Compostela, Santiago de Compostela, Spain
| | - María Tomás
- Department of Microbiology, Complejo Hospitalario Universitario A Coruña (CHUAC)-INIBIC, A Coruña, Spain
- Spanish Network for Research in Infectious Diseases (REIPI), Virgen Macarena, Seville, Spain
- * E-mail:
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Pragasam AK, Vijayakumar S, Bakthavatchalam YD, Kapil A, Das BK, Ray P, Gautam V, Sistla S, Parija SC, Walia K, Ohri VC, Anandan S, Veeraraghavan B. Molecular characterisation of antimicrobial resistance in Pseudomonas aeruginosa and Acinetobacter baumannii during 2014 and 2015 collected across India. Indian J Med Microbiol 2017; 34:433-441. [PMID: 27934820 DOI: 10.4103/0255-0857.195376] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND Surveillance of antimicrobial resistance (AMR) is of great importance. Pseudomonas aeruginosa and Acinetobacter baumannii are important pathogens and emergence of resistance in these have increased the morbidity and mortality rates. This surveillance study was initiated by the Government of India - Indian Council of Medical Research. The aim of this study is to determine the antimicrobial susceptibility profile and to characterise the enzyme mediated antimicrobial resistance such as extended spectrum beta-lactamases (ESBLs) and carbapenemases among multidrug-resistant (MDR) P. aeruginosa and A. baumannii. MATERIALS AND METHODS A multi-centric study was conducted from January 2014 to December 2015 with a total number of 240 MDR P. aeruginosa and 312 MDR A. baumannii isolated from blood, cerebrospinal fluid, respiratory, pus, urine and intra-abdominal infections. Kirby-Bauer disc diffusion was done to determine the antimicrobial susceptibility profile. Further, MDR isolates were characterised by multiplex polymerase chain reaction to determine the resistance genes for ESBLs and carbapenemases. RESULTS Among the ESBLs, blaVEB (23%), blaTEM (5%) and blaSHV (0.4%) in P. aeruginosa and blaPER (54%), blaTEM (16%) and blaSHV (1%) in A. baumannii were the most prevalent. Likewise, blaVIM (37%), blaNDM (14%), blaGES (8%) and blaIMP (2%) in P. aeruginosa and blaOXA-23like (98%), blaOXA-58like (2%), blaNDM (22%) and blaVIM (3%) in A. baumannii were found to be the most prevalent carbapenemases. blaOXA-51like gene, intrinsic to A. baumannii was present in all the isolates tested. CONCLUSION The data shown highlight the wide difference in the molecular mechanisms of AMR profile between P. aeruginosa and A. baumannii. In P. aeruginosa, plasmid-mediated mechanisms are much lesser than the chromosomal mediated mechanisms. In A. baumannii, class D oxacillinases are more common than other mechanisms. Continuous surveillance to monitor the trends in AMR among MDR pathogens is important for implementation of infection control and to guide appropriate empirical antimicrobial therapy.
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Affiliation(s)
- A K Pragasam
- Department of Clinical Microbiology, Christian Medical College, Vellore, Tamil Nadu, India
| | - S Vijayakumar
- Department of Clinical Microbiology, Christian Medical College, Vellore, Tamil Nadu, India
| | - Y D Bakthavatchalam
- Department of Clinical Microbiology, Christian Medical College, Vellore, Tamil Nadu, India
| | - A Kapil
- Department of Microbiology, All Institute of Medical Sciences, New Delhi, India
| | - B K Das
- Department of Microbiology, All Institute of Medical Sciences, New Delhi, India
| | - P Ray
- Department of Medical Microbiology, Post Graduate Institute of Medical Education and Research, Chandigarh, India
| | - V Gautam
- Department of Medical Microbiology, Post Graduate Institute of Medical Education and Research, Chandigarh, India
| | - S Sistla
- Department of Microbiology, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India
| | - S C Parija
- Department of Microbiology, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India
| | - K Walia
- Division of Epidemiology and Communicable Diseases, n Council for Medical Research, New Delhi, India
| | - V C Ohri
- Division of Epidemiology and Communicable Diseases, n Council for Medical Research, New Delhi, India
| | - S Anandan
- Department of Clinical Microbiology, Christian Medical College, Vellore, Tamil Nadu, India
| | - B Veeraraghavan
- Department of Clinical Microbiology, Christian Medical College, Vellore, Tamil Nadu, India
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Chemical Composition, Antioxidant, and Antibacterial Activity of Wood Vinegar from Litchi chinensis. Molecules 2016; 21:molecules21091150. [PMID: 27589711 PMCID: PMC6274201 DOI: 10.3390/molecules21091150] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 08/16/2016] [Accepted: 08/24/2016] [Indexed: 11/17/2022] Open
Abstract
The antioxidant and antibacterial activities of wood vinegar from Litchi chinensis, and its components have been studied. The chemical compositions of wood vinegar were analyzed by gas chromatography-mass spectrometry (GC-MS). A total of 17 chemical compounds were identified, representing 83.96% of the compositions in the wood vinegar. Three major components, included 2,6-dimethoxyphenol (syringol, 29.54%), 2-methoxyphenol (guaiacol, 12.36%), and 3,5-dimethoxy-4-hydroxytoluene (11.07%), were found in the wood vinegar. Antioxidant activities of the acids were investigated from the aspects of 1,1-Diphyl-2-picrylhydrazyl (DPPH) free radicals scavenging capacity, superoxide anion radical scavenging capacity, and reducing power. The pyroligneous acid exhibited high antioxidant activity which was comparable to the reference standards (vitamin C and butylated hydroxyl toluene) at the same dose with IC50 values of 36.5 ppm calculated by the DPPH radical scavenging assay, 38.38 g Trolox equivalent/100 g DW by the trolox equivalent antioxidant capacity (TEAC) assay, and 67.9 by the reducing power analysis. Antibacterial activity was evaluated using the disc diffusion and microdilution methods against a group of clinically antibiotic resistant isolates. The major components exhibited broad spectrum inhibition against all the bacterial strains with a range of disc inhibition zoon between 15–19 mm. The minimum inhibition concentration and minimum bactericide concentration against the test strains was ranging in 0.95–3.80 μL/100 μL and 1.90–3.80 μL/100 μL, respectively. Most of the antibiotic resistant strains were more susceptible to the wood vinegar than the non-antibiotic resistant strain except the strain of ornithine resistant Staphylococcus aureus. Based on the chemical profile, it was considered that the strongest antioxidant and antibacterial activity of Litchi chinensis wood vinegar was due to its highly phenolic compositions. This study revealed that the Litchi chinensis wood vinegar is valuable to develop as alternative food antioxidant and antibiotics.
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