1
|
Yuwono C, Wehrhahn MC, Liu F, Zhang L. Enteric Aeromonas Infection: a Common Enteric Bacterial Infection with a Novel Infection Pattern Detected in an Australian Population with Gastroenteritis. Microbiol Spectr 2023; 11:e0028623. [PMID: 37378724 PMCID: PMC10433960 DOI: 10.1128/spectrum.00286-23] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 06/07/2023] [Indexed: 06/29/2023] Open
Abstract
Aeromonas species are emerging human enteric pathogens. However, they are currently not routinely detected in many diagnostic laboratories, and information regarding Aeromonas enteric infections detected using molecular methods is lacking. Here, we investigated the detection of Aeromonas species and four other enteric bacterial pathogens in 341,330 fecal samples from patients with gastroenteritis processed in a large Australian diagnostic laboratory between 2015 and 2019. These enteric pathogens were detected using quantitative real-time PCR (qPCR) methods. Furthermore, we compared the qPCR cycle threshold (CT) values obtained from fecal samples that tested positive for Aeromonas only by molecular detection with those of samples that tested positive by both molecular detection and bacterial isolation methods. Aeromonas species were found to be the second most common bacterial enteric pathogens among patients with gastroenteritis. We observed a unique pattern of three infection peaks for Aeromonas, which correlated with the age of the patients. Aeromonas species were the most common enteric bacterial pathogens in children younger than 18 months. Fecal samples that tested positive for Aeromonas only by molecular detection had significantly higher CT values than fecal samples that tested positive by both molecular detection and bacterial culture. In conclusion, our findings reveal that Aeromonas enteric pathogens exhibit an age-related three-peak infection pattern, distinguishing them from other enteric bacterial pathogens. Moreover, the high rate of Aeromonas enteric infection discovered in this study suggests that Aeromonas species should be routinely tested in diagnostic laboratories. Our data also show that combining qPCR with bacterial culture can enhance the detection of enteric pathogens. IMPORTANCE Aeromonas species are emerging human enteric pathogens. However, these species are currently not routinely detected in many diagnostic laboratories, and no studies have reported the detection of Aeromonas enteric infection using molecular methods. We investigated the presence of Aeromonas species and four other enteric bacterial pathogens in 341,330 fecal samples from patients with gastroenteritis using quantitative real-time PCR (qPCR) methods. Interestingly, we discovered that Aeromonas species were the second most common bacterial enteric pathogens in patients with gastroenteritis, exhibiting a novel infection pattern compared to those of other enteric pathogens. Furthermore, we found that Aeromonas species were the most prevalent enteric bacterial pathogens in children aged 6 to 18 months. Our data also revealed that qPCR methods exhibit higher sensitivity in detecting enteric pathogens compared to that of bacterial culture alone. Moreover, combining qPCR with bacterial culture enhances the detection of enteric pathogens. These findings emphasize the importance of Aeromonas species in public health.
Collapse
Affiliation(s)
- Christopher Yuwono
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, Australia
| | | | - Fang Liu
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, Australia
| | - Li Zhang
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, Australia
| |
Collapse
|
2
|
Yang X, Yang Q, Guo Q, Yi C, Mao H, Lin J, Jiang Z, Yu X. Aeromonas Salmonicida Peritonitis after Eating Fish in a Patient Undergoing CAPD. Perit Dial Int 2020. [DOI: 10.1177/089686080802800323] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Affiliation(s)
- X. Yang
- Department of Nephrology The First Affiliated Hospital Sun Yat-sen University Guangzhou, China
| | - Q.Q. Yang
- Department of Nephrology The First Affiliated Hospital Sun Yat-sen University Guangzhou, China
| | - Q.Y. Guo
- Department of Nephrology The First Affiliated Hospital Sun Yat-sen University Guangzhou, China
| | - C.Y. Yi
- Department of Nephrology The First Affiliated Hospital Sun Yat-sen University Guangzhou, China
| | - H.P. Mao
- Department of Nephrology The First Affiliated Hospital Sun Yat-sen University Guangzhou, China
| | - J.X. Lin
- Department of Nephrology The First Affiliated Hospital Sun Yat-sen University Guangzhou, China
| | - Z.P. Jiang
- Department of Nephrology The First Affiliated Hospital Sun Yat-sen University Guangzhou, China
| | - X.Q. Yu
- Department of Nephrology The First Affiliated Hospital Sun Yat-sen University Guangzhou, China
| |
Collapse
|
3
|
Shakir Z, Khan S, Sung K, Khare S, Khan A, Steele R, Nawaz M. Molecular characterization of fluoroquinolone-resistant Aeromonas spp. isolated from imported shrimp. Appl Environ Microbiol 2012; 78:8137-41. [PMID: 22923408 PMCID: PMC3485934 DOI: 10.1128/aem.02081-12] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Accepted: 08/17/2012] [Indexed: 11/20/2022] Open
Abstract
Sixty-three nalidixic acid-resistant Aeromonas sp. isolates were obtained from imported shrimp. Phylogenetic analysis of gyrB sequences indicated that 18 were A. enteropelogenes, 26 were A. caviae, and 19 were A. sobria. Double missense mutations in the quinolone resistance-determining region (QRDR) of gyrA at codon 83 (Ser→Val/Ile) and codon 92 (Leu→Met) coupled with a point mutation of parC at codon 80 (Ser→Ile/Phe) conferred high levels of quinolone resistance in the isolates. A majority of A. enteropelogenes and A. caviae strains harbored toxin genes, whereas only a few A. sobria strains harbored these genes. The fluoroquinolone-resistant Aeromonas spp. exhibited higher cytotoxicity than fluoroquinolone-sensitive, virulent Aeromonas spp. to rat epithelial cells.
Collapse
Affiliation(s)
| | - Saeed Khan
- Division of Microbiology, U.S. Food and Drug Administration, National Center for Toxicological Research, Jefferson, Arkansas, USA
| | - Kidon Sung
- Division of Microbiology, U.S. Food and Drug Administration, National Center for Toxicological Research, Jefferson, Arkansas, USA
| | - Sangeeta Khare
- Division of Microbiology, U.S. Food and Drug Administration, National Center for Toxicological Research, Jefferson, Arkansas, USA
| | - Ashraf Khan
- Division of Microbiology, U.S. Food and Drug Administration, National Center for Toxicological Research, Jefferson, Arkansas, USA
| | - Roger Steele
- Division of Microbiology, U.S. Food and Drug Administration, National Center for Toxicological Research, Jefferson, Arkansas, USA
| | - Mohamed Nawaz
- Division of Microbiology, U.S. Food and Drug Administration, National Center for Toxicological Research, Jefferson, Arkansas, USA
| |
Collapse
|
4
|
Sreedharan K, Philip R, Singh ISB. Virulence potential and antibiotic susceptibility pattern of motile aeromonads associated with freshwater ornamental fish culture systems: a possible threat to public health. Braz J Microbiol 2012; 43:754-65. [PMID: 24031887 PMCID: PMC3768817 DOI: 10.1590/s1517-83822012000200040] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2010] [Accepted: 01/16/2012] [Indexed: 11/21/2022] Open
Abstract
Aeromonas spp. are ubiquitous aquatic organisms, associated with multitude of diseases in several species of animals, including fishes and humans. In the present study, water samples from two ornamental fish culture systems were analyzed for the presence of Aeromonas. Nutrient agar was used for Aeromonas isolation, and colonies (60 No) were identified through biochemical characterization. Seven clusters could be generated based on phenotypic characters, analyzed by the programme NTSYSpc, Version 2.02i, and identified as: Aeromonas caviae (33.3%), A. jandaei (38.3%) and A. veronii biovar sobria (28.3%). The strains isolated produced highly active hydrolytic enzymes, haemolytic activity and slime formation in varying proportions. The isolates were also tested for the enterotoxin genes (act, alt and ast), haemolytic toxins (hlyA and aerA), involved in type 3 secretion system (TTSS: ascV, aexT, aopP, aopO, ascF-ascG, and aopH), and glycerophospholipid-cholesterol acyltransferase (gcat). All isolates were found to be associated with at least one virulent gene. Moreover, they were resistant to frequently used antibiotics for human infections. The study demonstrates the pathogenic potential of Aeromonas, associated with ornamental fish culture systems suggesting the emerging threat to public health.
Collapse
Affiliation(s)
- Krishnan Sreedharan
- National Centre for Aquatic Animal Health, Cochin University of Science and Technology, Fine Arts Avenue, Cochin-682 016, Kerala, India
| | - Rosamma Philip
- Department of Marine Biology, Microbiology and Biochemistry, School of Marine Sciences, Cochin University of Science and Technology, Fine Arts Avenue, Cochin-682 016, Kerala, India
| | - Isaac Sarojani Bright Singh
- National Centre for Aquatic Animal Health, Cochin University of Science and Technology, Fine Arts Avenue, Cochin-682 016, Kerala, India
| |
Collapse
|
5
|
Rahouma A, Klena JD, Krema Z, Abobker AA, Treesh K, Franka E, Abusnena O, Shaheen HI, El Mohammady H, Abudher A, Ghenghesh KS. Enteric pathogens associated with childhood diarrhea in Tripoli-Libya. Am J Trop Med Hyg 2011; 84:886-91. [PMID: 21633024 DOI: 10.4269/ajtmh.2011.11-0116] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Stool samples from children < 5 years of age with diarrhea (N = 239) were examined for enteric pathogens using a combination of culture, enzyme-immunoassay, and polymerase chain reaction methods. Pathogens were detected in 122 (51%) stool samples; single pathogens were detected in 37.2% and co-pathogens in 13.8% of samples. Norovirus, rotavirus, and diarrheagenic Escherichia coli (DEC) were the most frequently detected pathogens (15.5%, 13.4%, and 11.2%, respectively); Salmonella, adenovirus, and Aeromonas were detected less frequently (7.9%, 7.1%, and 4.2%). The most commonly detected DEC was enteroaggregative E. coli (5.4%). Resistance to ≥ 3 antimicrobials was observed in 60% (18/30) of the bacterial pathogens. Salmonella resistance to ciprofloxacin (63.1%) has become a concern. Enteric viral pathogens were the most significant causative agents of childhood diarrhea in Tripoli. Bacterial pathogens were also important contributors to pediatric diarrhea. The emergence of ciprofloxacin-resistant Salmonella represents a serious health problem that must be addressed by Libyan health authorities.
Collapse
Affiliation(s)
- Amal Rahouma
- Departments of Microbiology and Immunology, Faculty of Medicine, Alfateh University, Tripoli, Libya.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
6
|
Pablos M, Huys G, Cnockaert M, Rodríguez-Calleja J, Otero A, Santos J, García-López M. Identification and epidemiological relationships of Aeromonas isolates from patients with diarrhea, drinking water and foods. Int J Food Microbiol 2011; 147:203-10. [DOI: 10.1016/j.ijfoodmicro.2011.04.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Revised: 03/29/2011] [Accepted: 04/05/2011] [Indexed: 11/24/2022]
|
7
|
Sreedharan K, Philip R, Singh ISB. Isolation and characterization of virulent Aeromonas veronii from ascitic fluid of oscar Astronotus ocellatus showing signs of infectious dropsy. DISEASES OF AQUATIC ORGANISMS 2011; 94:29-39. [PMID: 21553566 DOI: 10.3354/dao02304] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The cichlid oscar Astronotus ocellatus has worldwide commercial value in the pet fish industry because of its early maturation, relatively high fecundity, ability to identify its caretaker and also to alter colouration amongst conspecifics. Pathogenic strains of Aeromonas veronii resistant to multiple antibiotics were isolated from A. ocellatus individuals showing signs of infectious abdominal dropsy. The moribund fish showed haemorrhage in all internal organs, and pure cultures could be obtained from the abdominal fluid. The isolates recovered were biochemically identified as A. veronii biovar sobria and genetically confirmed as A. veronii based on 16S rRNA gene sequence analysis (GenBank accession no. FJ573179). The RAPD profile using 3 primers (OPA-3, OPA-4 and OPD-20) generated similar banding patterns for all isolates. They displayed cytotoxic and haemolytic activity and produced several exoenzymes which were responsible for the pathogenic potential of the isolates. In the representative isolate MCCB 137, virulence genes such as enterotoxin act, haemolytic toxin aerA, type 3 secretion genes such as aexT, ascVand ascF-ascG, and gcat (glycerophospholipid-cholesterol acyltransferase) could be amplified. MCCB 137 exhibited a 50% lethal dose (LD50) of 10(5.071) colony-forming units ml(-1) in goldfish and could be subsequently recovered from lesions as well as from the internal organs. This is the first description of a virulent A. veronii from oscar.
Collapse
Affiliation(s)
- K Sreedharan
- National Centre for Aquatic Animal Health, School of Marine Sciences, Cochin University of Science and Technology, Fine Arts Avenue, Cochin 682 016, Kerala, India
| | | | | |
Collapse
|
8
|
Parker JL, Shaw JG. Aeromonas spp. clinical microbiology and disease. J Infect 2010; 62:109-18. [PMID: 21163298 DOI: 10.1016/j.jinf.2010.12.003] [Citation(s) in RCA: 233] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2010] [Revised: 12/03/2010] [Accepted: 12/06/2010] [Indexed: 01/14/2023]
Abstract
Members of the genus Aeromonas inhabit various aquatic environments and are responsible for, and are implicated in, a number of intestinal and extra-intestinal infections in humans as well as other animals. This review focuses on invasive human infection and disease and summarizes available findings regarding the microbiology and detection of Aeromonas spp., with emphasis on successful identification and diagnosis, and the control of disease in the population. Antimicrobial resistance and therapy of Aeromonas spp. is also discussed.
Collapse
Affiliation(s)
- Jennifer L Parker
- Academic Unit of Immunology and Infectious Diseases, Department of Infection and Immunity, University of Sheffield Medical School, Beech Hill Road, Sheffield S10 2RX, UK
| | | |
Collapse
|
9
|
Identity, virulence genes, and clonal relatedness of Aeromonas isolates from patients with diarrhea and drinking water. Eur J Clin Microbiol Infect Dis 2010; 29:1163-72. [DOI: 10.1007/s10096-010-0982-3] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2009] [Accepted: 05/22/2010] [Indexed: 10/19/2022]
|
10
|
Leleiko NS, Gee MS, Sadow PM. Case records of the Massachusetts General Hospital. Case 13-2010. An 18.5-month-old girl with watery diarrhea and poor weight gain. N Engl J Med 2010; 362:1619-26. [PMID: 20427811 DOI: 10.1056/nejmcpc0910932] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
- Neal S Leleiko
- Department of Pediatrics, Alpert School of Medicine, Brown University, and the Division of Pediatric Gastroenterology, Nutrition, and Liver Diseases, Hasbro Children's Hospital-Rhode Island Hospital, Providence, USA
| | | | | |
Collapse
|
11
|
Tabei SMB, Hitchen PG, Day-Williams MJ, Merino S, Vart R, Pang PC, Horsburgh GJ, Viches S, Wilhelms M, Tomás JM, Dell A, Shaw JG. An Aeromonas caviae genomic island is required for both O-antigen lipopolysaccharide biosynthesis and flagellin glycosylation. J Bacteriol 2009; 191:2851-63. [PMID: 19218387 PMCID: PMC2668420 DOI: 10.1128/jb.01406-08] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2008] [Accepted: 02/02/2009] [Indexed: 11/20/2022] Open
Abstract
Aeromonas caviae Sch3N possesses a small genomic island that is involved in both flagellin glycosylation and lipopolysaccharide (LPS) O-antigen biosynthesis. This island appears to have been laterally acquired as it is flanked by insertion element-like sequences and has a much lower G+C content than the average aeromonad G+C content. Most of the gene products encoded by the island are orthologues of proteins that have been shown to be involved in pseudaminic acid biosynthesis and flagellin glycosylation in both Campylobacter jejuni and Helicobacter pylori. Two of the genes, lst and lsg, are LPS specific as mutation of them results in the loss of only a band for the LPS O-antigen. Lsg encodes a putative Wzx flippase, and mutation of Lsg affects only LPS; this finding supports the notion that flagellin glycosylation occurs within the cell before the flagellins are exported and assembled and not at the surface once the sugar has been exported. The proteins encoded by flmA, flmB, neuA, flmD, and neuB are thought to make up a pseudaminic acid biosynthetic pathway, and mutation of any of these genes resulted in the loss of motility, flagellar expression, and a band for the LPS O-antigen. Furthermore, pseudaminic acid was shown to be present on both flagellin subunits that make up the polar flagellum filament, to be present in the LPS O-antigen of the A. caviae wild-type strain, and to be absent from the A. caviae flmD mutant strain.
Collapse
Affiliation(s)
- S Mohammed B Tabei
- Unit of Infection and Immunity, School of Medicine and Biomedical Sciences, University of Sheffield, Sheffield S10 2RX, United Kingdom.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
12
|
Affiliation(s)
- Yu-Cheng Lin
- Department of Pediatrics, Far Eastern Memorial Hospital, Pan-Chiao, Taipei Hsien, Taiwan.
| |
Collapse
|
13
|
Kirov SM, Castrisios M, Shaw JG. Aeromonas flagella (polar and lateral) are enterocyte adhesins that contribute to biofilm formation on surfaces. Infect Immun 2004; 72:1939-45. [PMID: 15039313 PMCID: PMC375165 DOI: 10.1128/iai.72.4.1939-1945.2004] [Citation(s) in RCA: 138] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Aeromonas spp. (gram-negative, aquatic bacteria which include enteropathogenic strains) have two distinct flagellar systems, namely a polar flagellum for swimming in liquid and multiple lateral flagella for swarming over surfaces. Only approximately 60% of mesophilic strains can produce lateral flagella. To evaluate flagellar contributions to Aeromonas intestinal colonization, we compared polar and lateral flagellar mutant strains of a diarrheal isolate of Aeromonas caviae for the ability to adhere to the intestinal cell lines Henle 407 and Caco-2, which have the characteristic features of human intestinal enterocytes. Strains lacking polar flagella were virtually nonadherent to these cell lines, while loss of the lateral flagellum decreased adherence by approximately 60% in comparison to the wild-type level. Motility mutants (unable to swim or swarm in agar assays) had adhesion levels of approximately 50% of wild-type values, irrespective of their flagellar expression. Flagellar mutant strains were also evaluated for the ability to form biofilms in a borosilicate glass tube model which was optimized for Aeromonas spp. (broth inoculum, with a 16- to 20-h incubation at 37 degrees C). All flagellar mutants showed a decreased ability to form biofilms (at least 30% lower than the wild type). For the chemotactic motility mutant cheA, biofilm formation decreased >80% from the wild-type level. The complementation of flagellar phenotypes (polar flagellar mutants) restored biofilms to wild-type levels. We concluded that both flagellar types are enterocyte adhesins and need to be fully functional for optimal biofilm formation.
Collapse
Affiliation(s)
- Sylvia M Kirov
- Discipline of Pathology, University of Tasmania, Hobart, Tasmania 7001, Australia.
| | | | | |
Collapse
|
14
|
Béchet M, Blondeau R. Factors associated with the adherence and biofilm formation by Aeromonas caviae on glass surfaces. J Appl Microbiol 2003; 94:1072-8. [PMID: 12752817 DOI: 10.1046/j.1365-2672.2003.01931.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
AIMS Knowledge on factors of Aeromonas caviae promoting the formation of biofilms on surfaces. METHODS AND RESULTS In nutrient broth under agitation, A. caviae LMG 13455 was able to form biofilms on the surfaces of glass flasks, but such biofilm formation was inconsistent. A derivative of this strain, called M12, promoted the rapid formation of reliable and strongly adherent biofilms with about half of the cells being adhered. In contrast with its parent, M12 was hydrophobic, displayed auto-aggregation in liquid medium, synthesized very little polysaccharides and was defective in swimming and swarming motilities, together with the appearance of a characteristic phenotype on motility soft agar. Further analyses demonstrated that most of these properties were related to a hyperpiliation of the cells through the presence of type IV pili, and suggested that a mechanism of genetic variation, by altering the nature of motility appendages, allows the variant bacteria to attach on inert surfaces. CONCLUSIONS M12 is a stabilized variant of the parental strain, promoting strongly adherent biofilms through the type IV pili. SIGNIFICANCE AND IMPACT OF THE STUDY The wild-type strain A. caviae LMG 13455 include subpopulations that are likely implicated in its adaptation to different environmental changes.
Collapse
Affiliation(s)
- M Béchet
- Laboratoire de Microbiologie, Université des Sciences et Technologies de Lille, Villeneuve d'Ascq, France
| | | |
Collapse
|
15
|
Chapter 19 Culture media for Aeromonas spp. and Plesiomonas shigelloides. ACTA ACUST UNITED AC 2003. [DOI: 10.1016/s0079-6352(03)80022-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
|
16
|
Kirov SM, Tassell BC, Semmler ABT, O'Donovan LA, Rabaan AA, Shaw JG. Lateral flagella and swarming motility in Aeromonas species. J Bacteriol 2002; 184:547-55. [PMID: 11751834 PMCID: PMC139559 DOI: 10.1128/jb.184.2.547-555.2002] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2001] [Accepted: 10/20/2001] [Indexed: 11/20/2022] Open
Abstract
Swarming motility, a flagellum-dependent behavior that allows bacteria to move over solid surfaces, has been implicated in biofilm formation and bacterial virulence. In this study, light and electron microscopic analyses and genetic and functional investigations have shown that at least 50% of Aeromonas isolates from the species most commonly associated with diarrheal illness produce lateral flagella which mediate swarming motility. Aeromonas lateral flagella were optimally produced when bacteria were grown on solid medium for approximately 8 h. Transmission and thin-section electron microscopy confirmed that these flagella do not possess a sheath structure. Southern analysis of Aeromonas reference strains and strains of mesophilic species (n = 84, varied sources and geographic regions) with a probe designed to detect lateral flagellin genes (lafA1 and lafA2) showed there was no marked species association of laf distribution. Approximately 50% of these strains hybridized strongly with the probe, in good agreement with the expression studies. We established a reproducible swarming assay (0.5% Eiken agar in Difco broth, 30 degrees C) for Aeromonas spp. The laf-positive strains exhibited vigorous swarming motility, whereas laf-negative strains grew but showed no movement from the inoculation site. Light and scanning electron microscopic investigations revealed that lateral flagella formed bacterium-bacterium linkages on the agar surface. Strains of an Aeromonas caviae isolate in which lateral flagellum expression was abrogated by specific mutations in flagellar genes did not swarm, proving conclusively that lateral flagella are required for the surface movement. Whether lateral flagella and swarming motility contribute to Aeromonas intestinal colonization and virulence remains to be determined.
Collapse
Affiliation(s)
- Sylvia M Kirov
- Discipline of Pathology, University of Tasmania, Hobart, Tasmania 7001, Australia.
| | | | | | | | | | | |
Collapse
|
17
|
Gavín R, Rabaan AA, Merino S, Tomás JM, Gryllos I, Shaw JG. Lateral flagella of Aeromonas species are essential for epithelial cell adherence and biofilm formation. Mol Microbiol 2002; 43:383-97. [PMID: 11985716 DOI: 10.1046/j.1365-2958.2002.02750.x] [Citation(s) in RCA: 108] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Mesophilic Aeromonas strains express a single polar flagellum in all culture conditions and produce lateral flagella on solid media. Such hyperflagellated cells demonstrate increased adherence. Nine lateral flagella genes, lafA-U for Aeromonas hydrophila, and four Aeromonas caviae genes, lafA1, lafA2, lafB and fliU, were isolated. Mutant characterization, nucleotide and N-terminal sequencing demonstrated that the A. hydrophila and A. caviae lateral flagellins were almost identical, but were distinct from their polar flagellum counterparts. The aeromonad lateral flagellins exhibited higher molecular masses on SDS-PAGE, and this aberrant migration was thought to result from post-translational modification through glycosylation. Mutation of the Aeromonas lafB, lafS or both A. caviae lateral flagellins caused the loss of lateral flagella and a reduction in adherence and biofilm formation. Mutations in lafA1, lafA2, fliU or lafT resulted in strains that expressed lateral flagella, but had reduced adherence levels. Mutation of the lateral flagella loci did not affect polar flagellum synthesis, but the polarity of the transposon insertions on the A. hydrophila lafTlU genes resulted in non-motility. However, mutations that abolished polar flagellum production also inhibited lateral flagella expression. We conclude that Aeromonas lateral flagella: (i) play a role in adherence and biofilm formation; (ii) are distinct from the polar flagellum; (iii) synthesis is dependent upon the presence of a polar flagellum filament; and (iv) that the motor proteins of the polar and lateral flagella systems appear to be shared.
Collapse
Affiliation(s)
- Rosalina Gavín
- Departamento Microbiología, Facultad Biología, Universidad Barcelona, Spain
| | | | | | | | | | | |
Collapse
|
18
|
Rabaan AA, Gryllos I, Tomás JM, Shaw JG. Motility and the polar flagellum are required for Aeromonas caviae adherence to HEp-2 cells. Infect Immun 2001; 69:4257-67. [PMID: 11401962 PMCID: PMC98495 DOI: 10.1128/iai.69.7.4257-4267.2001] [Citation(s) in RCA: 108] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2000] [Accepted: 03/19/2001] [Indexed: 11/20/2022] Open
Abstract
Aeromonas caviae is increasingly being recognized as a cause of gastroenteritis, especially among the young. The adherence of aeromonads to human epithelial cells in vitro has been correlated with enteropathogenicity, but the mechanism is far from well understood. Initial investigations demonstrated that adherence of A. caviae to HEp-2 cells was significantly reduced by either pretreating bacterial cells with an antipolar flagellin antibody or by pretreating HEp-2 cells with partially purified flagella. To precisely define the role of the polar flagellum in aeromonad adherence, we isolated the A. caviae polar flagellin locus and identified five polar flagellar genes, in the order flaA, flaB, flaG, flaH, and flaJ. Each gene was inactivated using a kanamycin resistance cartridge that ensures the transcription of downstream genes, and the resulting mutants were tested for motility, flagellin expression, and adherence to HEp-2 cells. N-terminal amino acid sequencing, mutant analysis, and Western blotting demonstrated that A. caviae has a complex flagellum filament composed of two flagellin subunits encoded by flaA and flaB. The predicted molecular mass of both flagellins was approximately 31,700 Da; however, their molecular mass estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis was approximately 35,500 Da. This aberrant migration was thought to be due to their glycosylation, since the proteins were reactive in glycosyl group detection assays. Single mutations in either flaA or flaB did not result in loss of flagella but did result in decreased motility and adherence by approximately 50%. Mutation of flaH, flaJ, or both flagellin genes resulted in the complete loss of motility, flagellin expression, and adherence. However, mutation of flaG did not affect motility but did significantly reduce the level of adherence. Centrifugation of the flagellate mutants (flaA, flaB, and flaG) onto the cell monolayers did not increase adherence, whereas centrifugation of the aflagellate mutants (flaH, flaJ, and flaA flaB) increased adherence slightly. We conclude that maximum adherence of A. caviae to human epithelial cells in vitro requires motility and optimal flagellar function.
Collapse
Affiliation(s)
- A A Rabaan
- Division of Molecular and Genetic Medicine, University of Sheffield Medical School, Sheffield S10 2RX, United Kingdom
| | | | | | | |
Collapse
|
19
|
Gryllos I, Shaw JG, Gavín R, Merino S, Tomás JM. Role of flm locus in mesophilic Aeromonas species adherence. Infect Immun 2001; 69:65-74. [PMID: 11119490 PMCID: PMC97856 DOI: 10.1128/iai.69.1.65-74.2001] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The adherence mechanism of Aeromonas caviae Sch3N to HEp-2 cells was initially investigated through four mini-Tn5 mutants that showed a 10-fold decrease in adherence. These mutants lost motility, flagella, and their lipopolysaccharide (LPS) O antigen (O-Ag). Three genes, flmB-neuA-flmD, were found to be interrupted by the transposon insertions; additionally, two other genes, one lying upstream (flmA) and one downstream (neuB), were found to be clustered in the same operon. While the flmA and flmB genes were present in all mesophilic Aeromonas spp. (A. hydrophila, A. caviae, A. veronii bv. veronii, and A. veronii bv. sobria) tested, this was not the case for the neuA-flmD-neuB genes. Construction and characterization of flmB insertion mutants in five other mesophilic Aeromonas strains revealed the loss of motility, flagella, and adherence but did not alter the LPS composition of these strains. Taking the above findings into consideration, we conclude (i) that flagella and possibly the LPS O-Ag are involved in the adherence of the mesophilic Aeromonas to human epithelial cells; (ii) flmA and flmB are genes widely distributed in the mesophilic Aeromonas and are involved in flagella assembly, and thus adherence; and (iii) in A. caviae Sch3N the flmA and flmB genes are found in a putative operon together with neuA, flmD, and neuB and are involved in LPS O-Ag biosynthesis and probably have a role in flagellum assembly.
Collapse
Affiliation(s)
- I Gryllos
- Division of Molecular and Genetic Medicine, University of Sheffield Medical School, Sheffield S10 2RX, United Kingdom
| | | | | | | | | |
Collapse
|
20
|
Itoh H, Kuwata G, Tateyama S, Yamashita K, Inoue T, Kataoka H, Ido A, Ogata K, Takasaki M, Inoue S, Tsubouchi H, Koono M. Aeromonas sobria infection with severe soft tissue damage and segmental necrotizing gastroenteritis in a patient with alcoholic liver cirrhosis. Pathol Int 1999; 49:541-6. [PMID: 10469397 DOI: 10.1046/j.1440-1827.1999.00920.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A 49-year-old man, who had a 3-year history of liver dysfunction but had not been treated, was admitted to the hospital with a sudden onset of fever and generalized muscle pain. He subsequently developed generalized purpura with scattered hemorrhagic bullae of the skin and massive bloody stools. Aeromonas sobria was proven by culture of both blood and bullous fluid. In spite of the extensive treatment with antibiotics and other medications in the intensive care unit (ICU), the patient went into septic shock and died 2 days after admission. Pathological examination on autopsy revealed segmental necrotizing gastroenteritis with bacterial colonies and alcoholic liver cirrhosis, in addition to extensive severe soft tissue damage involving cellulitis and rhabdomyolysis and epidermolysis. Although the prognosis for Vibrio vulnificus infection with severe soft tissue damage in patients with liver cirrhosis, malignancy, diabetes mellitus or other pre-existing diseases is poor, the unfavorable progression of Aeromonas species, especially A. sobria infection is rare. This is thought to be the first report of an autopsied case.
Collapse
Affiliation(s)
- H Itoh
- Second Department of Pathology, Miyazaki Medical College, Japan
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
21
|
|
22
|
Gobat PF, Jemmi T. Comparison of seven selective media for the isolation of mesophilic Aeromonas species in fish and meat. Int J Food Microbiol 1995; 24:375-84. [PMID: 7710914 DOI: 10.1016/0168-1605(94)00043-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Seven selective agar media and two enrichment broths were evaluated for their suitability for the isolation of mesophilic Aeromonas species from meat, fish, and shellfish samples. In a first trial, aeromonads were inoculated in fish and meat samples and reisolated using all selected media. For qualitative isolation, enrichment in alkaline peptone water (pH 8.7 +/- 0.1) at 28 degrees C and subsequent plating onto sheep blood agar supplemented with 30 mg/L ampicillin (ASBA 30) and bile salts-irgasan-brilliant green agar (BIBG) at 35 degrees C led to the best results. For quantitative assays, direct plating on the same agar media is recommended. In a second trial, 829 meat, fish, and shellfish samples were investigated with the same methods. The results show that BIBG is the most selective medium and that presumptive identification of aeromonads on ASBA 30 is very easy. Finally, we could confirm the opinion of other workers that optimal recovery of mesophilic Aeromonas spp. requires the use of more than one agar medium.
Collapse
Affiliation(s)
- P F Gobat
- Microbiology Section, Federal Veterinary Office, Liebefeld-Bern, Switzerland
| | | |
Collapse
|
23
|
Wilcox MH, Cook A, Geary I, Eley A. Toxin production, adherence and protein expression by clinical Aeromonas spp. isolates in broth and human pooled ileostomy fluid. Epidemiol Infect 1994; 113:235-45. [PMID: 7925662 PMCID: PMC2271534 DOI: 10.1017/s0950268800051669] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The physiological behaviour of clinical Aeromonas spp. isolates was compared following culture in a conventional broth and human pooled ileostomy fluid (PIF). Protein expression was markedly affected by the growth medium, with an overall reduction in whole cell proteins in bacteria grown in ileostomy fluid. In addition, novel outer membrane proteins were produced in PIF but not in broth. The majority of A. hydrophila and A. sobria isolates produced toxin in both broth and PIF, whereas no cytotoxin positive A. caviae were found. Toxin titres were at least two doubling dilutions higher in 40% and 21% of A. hydrophila and A. sobria isolates, respectively, following culture in brain heart infusion broth compared with PIF. Bacterial adherence to Vero and A-549 cells was significantly more common in A. hydrophila (53%) and A. sobria (64%) than in A. caviae (15%) (P < 0.01). We observed increased adherence by 6 aeromonas strains previously classified as adherence-positive, but not by 6 non-adherers, in PIF compared with brain heart infusion broth. The influence of growth medium on the expression of potential virulence determinants by Aeromonas spp. provides a rationale for the use of human ileostomy fluid in future in vitro studies, in order to simulate the nutrient conditions found in vivo.
Collapse
Affiliation(s)
- M H Wilcox
- Department of Experimental and Clinical Microbiology, University of Sheffield Medical School
| | | | | | | |
Collapse
|
24
|
Carey PE, Eley A, Wilcox MH. Assessment of a chemiluminescent universal probe for taxonomical and epidemiological investigations of Aeromonas sp isolates. J Clin Pathol 1994; 47:642-6. [PMID: 8089222 PMCID: PMC502102 DOI: 10.1136/jcp.47.7.642] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
AIMS To assess a chemiluminescent universal probe for taxonomical and epidemiological investigations of Aeromonas sp isolates. METHODS Total DNA was extracted from 69 well characterised Aeromonas sp strains and digested with the restriction endonucleases Sma I or Pst I. Following electrophoresis, the resulting fragments were transferred to a nylon membrane where they were hybridised to a commercially available universal probe of 16S + 23S rRNA. The banding patterns (ribotypes) were made visible by enhanced chemiluminescence. RESULTS Both restriction endonucleases produced heterogeneous ribotypes so that no allocation could be made to any of the control genospecies tested. For A hydrophila and A caviae, however, groups of strains (mostly from the same patient) could be identified by indistinguishable banding patterns. A relatively high proportion (36%) of A sobria strains were non-typable. CONCLUSIONS Although this universal chemiluminescent probe is user friendly, it is unsuitable for taxonomical investigations of Aeromonas sp. It is useful in epidemiological studies of A hydrophila and A caviae, but is of less value for A sobria.
Collapse
Affiliation(s)
- P E Carey
- Department of Experimental and Clinical Microbiology, University of Sheffield Medical School
| | | | | |
Collapse
|
25
|
Abstract
There is now evidence that some strains of Aeromonas species are enteropathogens. Such strains possess virulence properties, such as the ability to produce enterotoxins, cytotoxins, haemolysins and/or the ability to invade epithelial cells. Strains with these properties are common contaminants of drinking water and a wide range of foods. Contact or consumption of contaminated water, especially in summer, is a major risk factor in Aeromonas-associated gastroenteritis. Aeromonas-contaminated foods may also be vehicles of infection. Given the properties of strains that have been described in foods it has been suggested that food-borne illness could result not only from colonization and in vivo expression of virulence factors, but possibly also by intoxication following ingestion of foods that have been stored for a period of time, even under refrigeration. This paper reviews what is known about Aeromonas spp. in foods, their expression of virulence determinants, particularly at refrigeration temperatures, and the questions remaining to be answered to evaluate the risk they pose, so that an appropriate public health response can be determined.
Collapse
Affiliation(s)
- S M Kirov
- Department of Pathology, University of Tasmania Clinical School, Hobart, Australia
| |
Collapse
|
26
|
Wilcox MH, Cook AM, Thickett KJ, Eley A, Spencer RC. Phenotypic methods for speciating clinical Aeromonas isolates. J Clin Pathol 1992; 45:1079-83. [PMID: 1479034 PMCID: PMC495001 DOI: 10.1136/jcp.45.12.1079] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
AIMS To establish the suitability of currently available phenotypic methods for speciation of clinical Aeromonas isolates in diagnostic microbiology laboratories. METHODS Using 62 Aeromonas spp, three schemes based on biochemical reactions were compared: a series of conventional tests; a system based on the suicide phenomenon, comprising two tubes in total; and a commercially available test, API 20 NE, augmented with a plate assay for beta haemolysin production. The whole cell and outer membrane protein (OMP) profiles of strains were examined by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS PAGE), according to the results of the above schemes, to determine the intra-species homogeneity. RESULTS Ninety per cent of strains were identified satisfactorily according to conventional criteria. For these strains, agreement was obtained using the suicide phenomenon and API schemes in 93% and 88% of cases, respectively. The three schemes concurred for 82% of strains. Whole cell protein profiles were unsuitable for comparing strains within a species. However, OMP patterns were similar for 89% of A caviae and 63% of A hydrophila. CONCLUSION Phenospeciation of clinical Aeromonas isolates by the scheme based on the suicide phenomenon is simple to perform and accurate, and suitable for use in the diagnostic laboratory. OMP profiles are potentially useful for confirming the identity of A caviae and most A hydrophila, but not A sobria.
Collapse
Affiliation(s)
- M H Wilcox
- Department of Experimental and Clinical Microbiology, University of Sheffield Medical School, Sheffield
| | | | | | | | | |
Collapse
|