Department: Pathobiology and Population Sciences

Campus: Hawkshead

Research Groups: Antimicrobial Resistance, Host-Pathogen Interactions and Vaccinology, IRLFS (Research Programme)

Professor Rycroft holds the chair of Clinical and Veterinary Microbiology at the RVC.  His research, in porcine respiratory disease, has explored mechanisms of bacterial survival in the host and development of effective vaccination. His group has developed the means for genetic manipulation of Mycoplasma hyopneumoniae and used this to generate knock-out mutants to investigate the functions required for evading the host immune response and for generting disease (enzootic pneumonia).  They have also expressed genes from M. hyopneumoniae as a means of tagging the live pathogen during interaction with host cells.  He is also recognised for his work on Actinobacillus pleuropneumoniae and problems of immunological control of contagious pleuropneumonia in the farm.

He is a teacher of Veterinary Bacteriology and Mycology, a Fellow of the Royal Society of Biology and Fellow of the Royal College of Pathologists.

Professor Rycroft graduated in Microbiology from the University of Leeds in 1980. He continued there to complete a PhD researching the role of bacterial surface components in complement- and phagocytosis-resistance in E. coli. Using genetic techniques, with clinical isolates responsible for neonatal meningitis and septicaemia, he was able to demonstrate the key role of bacterial surface polysaccharides in survival in the host, and that exchanging those antigens in the same genetic background, altered the interaction between the pathogen and host defences.

In 1983, Andrew moved to Glasgow University Veterinary School as Lecturer in Bacteriology. It was here that he began investigating the pig pathogen Actinobacillus pleuropneumoniae.  This included work on the interaction of A. pleuropneumoniae with porcine complement and, with grants from AFRC & Wellcome Trust, the discrimination and characterisation of the potent pig-specific cytotoxins including discvery of ApxIII, now recognised as cytolytic toxins of the RTX group.

At this time, Andrew also developed a small mycology diagnostic unit, taking over from Dr Christine Dawson. This included pharmaceutical trials and research on practical aspects of fungal infection in animals such as the relative effect of different disinfectants on killing dermatophyte fungi (Microsporum canis) taken directly from the naturally infected animal - as would be found in the home or cattery environment.

After nine years in Glasgow, Andrew moved to the RVC in 1992 as Senior Lecturer in Veterinary Microbiology and Head of Bacteriology. This was an opportunity to formulate the teaching of veterinary microbiology to veterinary students. This he has continued to develop and to integrate microbiology and infectious diseases into relevant strands of veterinary medicine, veterinary nursing and BSc bioveterinary sciences.

In 2006 Andrew became Reader in Infectious Diseases and in January 2007 was promoted to Professor of Clinical and Veterinary Microbiology.  He has four adult children and two grandchildren.   He sails, cycles and grows citrus fruit. 

Andrew's research at RVC has encompassed a broad range of bacterial pathogens of animals including A. pleuropneumoniae, Bordetella bronchiseptica, Mannheimia haemolytica, Leptospira canicola, Streptococcus suis and Mycoplasma hyopneumoniae. Investigations have been focused on understanding toxin and cell-surface mechanisms of bacterial pathogenicity and investigations towards developing newer and better means of vaccinating pigs against bacterial infectious disease, primarily pneumonia, for which he is internationally recognised. These studies have now focussed on development of defined, live-attenuated vaccines against pneumonia. Prof Rycroft has also worked with Prof Martin Sheldon on the pathophysiology of post-partum bacterial reproductive tract infection in cattle, and conducted a number of clinical studies for testing and commercial registration of vaccines, antimicrobials and animal health products for the pig and the dog.
Andrew was a partner in a DEFRA-funded project with Prof. Peter Lees to determine the value of PK/PD modelling in setting dose levels for antimicrobials, used in treatment of calf pneumonia (pasteurellosis), to minimise the emergence of antimicrobial resistance. He has worked in close collaboration with Prof Paul Langford and Dr Janine Bossé & Dr Brian Sheehan of Imperial College using STM to identify genes required for pathogenicity of A. pleuropneumoniae and in evaluating the role of specific genes of A. pleuropneumoniae in colonising the pig respiratory tract.

His current research is funded by BBSRC and MRC grants, with funding from DEFRA and Zoetis to develop a vaccine and diagnostic system to control bacterial respiratory disease in the pig.  The primary goals of the work at RVC have been to develop genetic tools for Mycoplasma hyopneumoniae and to use these to identify novel vaccine candidates to control porcine enzootic pneumonia.  More than 120 strains of M. hyopneumoniae have been collected and the whole genome sequence of each determined.  The group (Dr Jess Beddow, Dr Laila el Attar and Alannah Deeney) has now achieved transformation of M. hyopneumoniae using artificial plasmids and devised techniques for efficient transposon mutagenesis in this pathogen.  This allowed functional genomic analysis of M. hyopneumoniae in vivo with testing of a number of defined mutants and analysis of these towards improved understanding the interaction of pathogen with the pig host.

He has a long-standing collaboration with Prof Paul Langford and Dr Janine Bossé of Imperial College to understand pathogenicity mechanisms of the pig respiratory pathogen Actinobacillus pleuropneumoniae.  He was recently awarded an MRC grant with Prof Brian Catchpole to develop an improved method for immunizing pigs against contagious pleuropneumonia based on neutralization of the Apx toxins.  This work is conducted with Dr Francesca Soutter.  The group is also researching a novel, vaccine-based approach to control bovine staphylococcal mastitis.

He is a past Editor of FEMS Microbiology Letters and served on the Editorial Board of Research in Veterinary Science; he is currently an editorial advisor to the Journal of Comparative Pathology.

Generation and Evaluation of a Glaesserella (Haemophilus) parasuis Capsular Mutant.
Eberle KC, Hau SJ, Luan SL, Weinert LA, Stasko JA, Wang J, Peters SE, Langford PR, Rycroft AN, Wren BW, Maskell DJ, Tucker AW, Brockmeier SL. Infect Immun. 2020 Apr 20;88(5):e00879-19. doi: 10.1128/IAI.00879-19.

Evaluation of the recombinant proteins RlpB and VacJ as a vaccine for protection against Glaesserella parasuis in pigs.
Hau SJ, Luan SL, Loving CL, Nicholson TL, Wang J, Peters SE, Seilly D, Weinert LA, Langford PR, Rycroft AN, Wren BW, Maskell DJ, Tucker AW, Brockmeier SL; BRaDP1T Consortium.Version 2. BMC Vet Res. 2020 May 27;16(1):167. doi: 10.1186/s12917-020-02377-5

Mead, A; Lees, P; Mitchell, J; Rycroft, A; Standing, J F; Toutain, P-L, Pelligand, L.
Differential susceptibility to tetracycline, oxytetracycline and doxycycline of the calf pathogens Mannheimia haemolytica and Pasteurella multocida in three growth media.

Wileman, T M; Weinert, L A; Howell, K J; Wang, J; Peters, S E; Williamson, S M; Wells, J M; Langford, P R; Rycroft, A N; Wren, B W; Maskell, D J; Tucker, A W.
Pathotyping the Zoonotic Pathogen Streptococcus suis: Novel Genetic Markers To Differentiate Invasive Disease-Associated Isolates from Non-Disease-Associated Isolates from England and Wales.

Deeney, A S; Maglennon, G A; Chapat, L; Crussard, S; Jolivet, E; Rycroft, A N.
Mycoplasma hyopneumoniae evades phagocytic uptake by porcine alveolar macrophages in vitro.

Bossé, J T; Li, Y; Fernandez Crespo, R; Lacouture, S; Gottschalk, M; Sárközi, R; Fodor, L; Amoribieta, M C; Angen, Ø; Nedbalcova, K; Holden, M T G; Maskell, D J; Tucker, A W; Wren, B W; Rycroft, A N; Langford, P R.
Comparative sequence analysis of the capsular polysaccharide loci of Actinobacillus pleuropneumoniae serovars 1-18, and development of two multiplex PCRs for comprehensive capsule typing.

Bossé, J T; Li, Y; Sárközi, R; Fodor, L; Lacouture, S; Gottschalk, M; Amoribieta, M C; Angen, Ø; Nedbalcova, K; Holden, M T G; Maskell, D J; Tucker, A W; Wren, B W; Rycroft, A N; Langford, P R.
Proposal of serovars 17 and 18 of Actinobacillus pleuropneumoniae based on serological and genotypic analysis.

Brockmeier, S L; Loving, Cl L; Nicholson, T L; Wang, J; Peters, S E; Weinert, L; Chaudhuri, R; Seilly, D J; Langford, P R; Rycroft, A; Wren, B W; Maskell, D J; Tucker, A W.
Use of proteins identified through a functional genomic screen to develop a protein subunit vaccine that provides significant protection against virulent Streptococcus suis in pigs.
INFECTION AND IMMUNITY, 86;3:e00559-17. 2018

Bruce, H L; Barrow, P A; Rycroft, A N.
Zoonotic potential of Salmonella enterica carried by pet tortoises.

BOSSÉ, J.T., LI, Y., ROGERS, J. FERNANDEZ-CRESPO, R., LI, Y., CHAUDHURI, R.R., HOLDEN, M.T.G., MASKELL, D.J., TUCKER, A.W., WREN, B.W., RYCROFT, A.N., LANGFORD, P.R.   (2017).  Whole genome sequencing for surveillance of antimicrobial resistance in Actinobacillus pleuropneumoniae.  Frontiers in Microbiology  8, 311.        PMID: 28321207

BOSSÉ, J.T., LI, Y., SÁRKÖSI, R., GOTTSCHALK, M., ANGEN, Ø., NEDBALCOVA, K., RYCROFT, A.N., FODOR, L. & LANGFORD, P.R. (2017). A unique capsule locus in the newly designated Actinobacillus pleuropneumoniae serovar 16 and development of a diagnostic PCR.  Journal of Clinical Microbiology 55, 902-907.  PMID: 28053219

CUCCUI, J., TERRA, V.S., BOSSÉ, J.T., NAEGELI, A., ABOUELHADID, S., LI,Y., LIN, C.W., VOHRA, P., TUCKER, A.W., RYCROFT, A.N., MASKELL, D.J., AEBI, M., LANGFORD, P.R. & WREN, B.W. (2017).  The N-linking glycosylation system from Actinobacillus pleuropneumoniae is required for adhesion and has potential use in glycoengineering.  Open Biology, 7, 160212.   PMID: 28077594

COOK, B.S., BEDDOW, J.G., MANSO-SILVÁN, L., MAGLENNON, G.A. & RYCROFT, A.N. (2016) Selective medium for culture of Mycoplasma hyopneumoniaeVeterinary Microbiology 195, 158–164.  PMID: 27771062

LEES, P., ILAMBAS, J., POTTER, T., PELLIGAND, L. RYCROFT, A.N. & TOUTAIN, P-L. (2016).  A large potentiation effect of serum on the in vitro potency of tulathromycin against Mannheimia haemolytica and Pasteurella multocida.  Journal of veterinary pharmacology and therapeutics    PMID: 27891615

BOSSÉ, J.T., LI,Y., CRESPO, R.F., CHAUDHURI, R.R., ROGERS, J., HOLDEN, M.T., MASKELL, D., TUCKER, A.W. WREN, B.W., RYCROFT, A.N. & LANGFORD, P.R.  (2016).  ICEApl1, an integrative conjugative element related to ICEHin1056, identified in the pig pathogen Actinobacillus pleuropneumoniaeFrontiers in Microbiology, 7, 810.  PMID: 27379024

LI, Y., BOSSÉ, J.T., WILLIAMSON, S.M., MASKELL, D.J., TUCKER, A.W. WREN, B.W., RYCROFT, A.N. & LANGFORD, P.R. (2016).  Actinobacillus pleuropneumoniae serovar 8 predominates in England and Wales.  Veterinary Record 179, 276.  PMID: 27531715

BOSSÉ, J.T., CHAUDHURI, R.R., LI, Y., LEANSE, L.G., FERNANDEZ CRESPOA, R., COUPLAND, P., HOLDEN, M.T.G., BAZZOLI, D.M., MASKELL, D.J., TUCKER, A.W., WREN, B.W., RYCROFT, A.N., LANGFORD, P.R.   (2016)Complete Genome Sequence of MIDG2331, a Genetically Tractable Serovar 8 Clinical Isolate of Actinobacillus pleuropneumoniae.  Genome Anouncements. 4, e01667-15.   PMID: 26823596

BOSSÉ, J.T., LI, Y., ATHERTON, T.G., WALKER, S., WILLIAMSON, S.M., ROGERS, J., CHAUDHURI, R.R., WEINERT, L.A., HOLDEN, M.T., MASKELL, D.J., TUCKER, A.W., WREN, B.W., RYCROFT, A.N., LANGFORD, P.R.  (2015). Characterisation of a mobilisable plasmid conferring florfenicol and chloramphenicol resistance in Actinobacillus pleuropneumoniaeVeterinary Microbiology 178, 279-282.          PMID: 26049592

HOWELL, K.J., PETERS, S.E., WANG, J., HERNANDEZ-GARCIA, J., WEINERT, L.A., LUAN, S.L., CHAUDHURI, R.R., ANGEN, Ø., ARAGON, V., WILLIAMSON, S.M., PARKHILL, J., LANGFORD, P.R., RYCROFT, A.N., WREN, B.W., MASKELL, D.J., TUCKER, A.W.  (2015). Development of a multiplex PCR for rapid molecular serotyping of Haemophilus parasuisJournal of Clinical Microbiology 53, 3812–3821.      PMID: 26424843

BAIG, A., WEINERT, L.A., PETERS, S.E., HOWELL, K.J., CHAUDHURI, R.R., WANG, J., HOLDEN, M.T., S.M., PARKHILL, J., LANGFORD, P.R., RYCROFT, A.N., WREN, B.W., TUCKER, A.W. & MASKELL, D.J. (2015).  Whole genome investigation of a divergent clade of the pathogen Streptococcus suis.  Frontiers in Microbiology 6, 1191PMID: 26583006

LEES, P., PELLIGAND, L., ILLAMBAS, J., POTTER, T., LACROIX, M., RYCROFT, A.N. & TOUTAIN, P.L.  (2015). Pharmacokinetic/pharmacodynamic integration and modelling of amoxicillin for the calf pathogens Mannheimia haemolytica and Pasteurella multocidaJournal of Veterinary Pharmacology & Therapeutics 38, 457-470.     PMID: 25669418

WEINERT, L.A., CHAUDHURI, R.R., WANG, J., PETERS, S.E., CORANDER, J., JOMBART, T., BAIG, A., HOWELL, K.J., VEHKALA, M., VÄLIMÄKI, N., HARRIS, D., CHIEU, T.T., VAN VINH CHAU, N., CAMPBELL, J., SCHULTSZ, C., PARKHILL, J., BENTLEY, S.D., LANGFORD, P.R., RYCROFT, A.N., WREN, B.W., FARRAR, J., BAKER, S., HOA, N.T., HOLDEN, M.T., TUCKER, A.W. & MASKELL, D.J.  (2015). Genomic signatures of human and animal disease in the zoonotic pathogen Streptococcus suisNature Communications 31, 6740.      PMID: 25824154

BOSSÉ, J.T., LI, Y., WALKER, S., ATHERTON, T., FERNANDEZ CRESPO, R., WILLIAMSON, S.M., ROGERS, J., CHAUDHURI, R.R., WEINERT, L.A., OSHOTA, O., HOLDEN, M.T., MASKELL, D.J., TUCKER, A.W., WREN, B.W., RYCROFT, A.N., LANGFORD, P.R. (2015). Identification of dfrA14 in two distinct plasmids conferring trimethoprim resistance in Actinobacillus pleuropneumoniaeJournal of Antimicrobial Chemotherapy 70, 2217–2222.  PMID: 25957382

HOWELL, K,.J., WEINERT, L.A., CHAUDHURI, R.R., LUAN, S.L., PETERS, S.E., CORANDER, J., HARRIS, D., ANGEN, Ø., ARAGON, V., BENSAID, A., WILLIAMSON, S.M., PARKHILL, J., LANGFORD, P.R., RYCROFT, A.N., WREN, B.W., HOLDEN, M.T., TUCKER, A.W. & MASKELL, D.J.  (2014). The use of genome wide association methods to investigate pathogenicity, population structure and serovar in Haemophilus parasuisBMC Genomics 15, 1179.  PMID: 25539682

RHYND, K.J., LEIGHTON, P.A., ELCOCK, D.A., WHITEHALL, P.J., RYCROFT, A.N. & MACGREGOR S.K. (2014).  Prevalence of Salmonella spp. and thermophilic Campylobacter spp. in the small Asian mongoose (Herpestes javanicus) in Barbados, West Indies.  Journal of Zoological & Wildlife Medicine 45, 911-914.    PMID: 25632681

BOSSÉ, J.T., SOARES-BAZZOLLI, D.M., LI, Y., WREN, B.W., TUCKER, A.W., MASKELL, D.J., RYCROFT, A.N., LANGFORD, P.R.  BRaDP1T Consortium.  (2014).  The generation of successive unmarked mutations and chromosomal insertion of heterologous genes in Actinobacillus pleuropneumoniae using natural transformation.  PLoS One 9:e111252.  PMID: 25409017

RUTHERFORD, S.J., RYCROFT, A.N. & RIDLER, A.L. (2014). Sources of Streptococcus dysgalactiae in English and Welsh sheep flocks affected by infectious arthritis (joint ill). Veterinary Record. 174, 579.  PubMed:24619629

BOSSÉ, J.T., LI, Y., ANGEN, O., WEINERT, L.A., CHAUDHURI, R.R., HOLDEN, M.T., WILLIAMSON, S.M., MASKELL, D.J., TUCKER, A.W., WREN, B.W., RYCROFT, A.N., LANGFORD, P.R. (2014). Multiplex PCR assay for Unequivocal Differentiation of Actinobacillus pleuropneumoniae Serovars 1 to 3, 5 to 8, 10 and 12. J.Clin.Microbiol. 52, 2380-2385.  PubMed:24759717

MAGLENNON, G.A., COOK, B.S., DEENEY, A.S., BOSSÉ, J.T., PETERS, S.E., LANGFORD, P.R., MASKELL, D.J., TUCKER, A.W., WREN, B.W. & RYCROFT, A.N. (2013). Transposon mutagenesis in Mycoplasma hyopneumoniae using a novel mariner-based system for generating random mutations. Veterinary Research 44, 124.  Pubmed ID: 24359443

SIDHU, P., RASSOULI, A., ILLAMBAS, J., POTTER, T., PELLIGAND, L., RYCROFT, A. & LEES P. Pharmacokinetic-pharmacodynamic integration and modelling of florfenicol in calves. (2013). J Vet Pharmacol Therapeutics. Dec 16. doi: 10.1111/jvp.12093.  PubMed ID: 24341543

LUAN, S.L., CHAUDHURI, R.R., PETERS, S.E., MAYHO, M., WEINERT, L.A., CROWTHER, S.A., WANG, J., LANGFORD, P.R., RYCROFT, A.N., WREN, B.W., TUCKER, A.W. & MASKELL, D.J. (2013). Generation of a Tn5 transposon library in Haemophilus parasuis and analysis by transposon-directed insertion-site sequencing (TraDIS). Veterinary Microbiol. 166, 558-566.  PubMed ID: 23928120

MAGLENNON, G.A., COOK, B.S., MATTHEWS, D., DEENEY, A.S., BOSSÉ, J.T., LANGFORD, P.R., MASKELL, D.J., TUCKER, A.W., WREN, B.W. & RYCROFT, A.N. (2013). Development of a self-replicating plasmid system for Mycoplasma hyopneumoniae. Veterinary Research 44, 63.  Pubmed ID: 23895236

HOWELL, K.J., WEINERT, L.A., LUAN, S.L., PETERS, S.E., CHAUDHURI, R.R., HARRIS, D., ANGEN, O., ARAGON, V., PARKHILL, J., LANGFORD, P.R., RYCROFT, A.N., WREN, B.W., TUCKER, A.W., MASKELL, D.J.; on behalf of the BRADP1T Consortium. (2013). Gene content and diversity of the loci encoding biosynthesis of capsular polysaccharides of the fifteen serovar reference strains of Haemophilus parasuis. Journal of Bacteriology, 195, 4264-4273.  Pubmed ID:23873912 

ILLAMBAS, J., POTTER, T., CHENG, Z., RYCROFT, A.N., FISHWICK, J. & LEES, P. (2013). Pharmacodynamics of marbofloxacin for calf pneumonia pathogens. Research in Veterinary Science 94, 675-681.  Pubmed ID: 23375665

ILLAMBAS, J., POTTER, T., SIDHU, P., RYCROFT, A.N., CHENG, Z. & LEES, P. (2013). Pharmacodynamics of florfenicol for calf pneumonia pathogens. Veterinary Record. 172, 340.  PubMed ID: 23482237

Pharmacokinetic and pharmacodynamic integration and modelling of marbofloxacin in calves for Mannheimia haemolytica and Pasteurella multocida. Veterinary Journal 195, 53-58.  Pubmed ID: 23084327

ASSAVACHEEP, P. & RYCROFT, A.N. (2013). Survival of Actinobacillus pleuropneumoniae outside the pig. Research in Veterinary Science 94, 22-26. PubMed ID 22892250

Significant publications in contagious porcine pleuropneumonia:

SHEEHAN, B. J., BOSSE, J. T., BEDDEK, A. J., RYCROFT, A. N., KROLL, J. S. & LANGFORD, P. R. (2003) Identification of Actinobacillus pleuropneumoniae genes important for survival during infection in its natural host. Infect Immun 71, 3960-3970. PubMed ID 12819083

GARSIDE, L. H., COLLINS, M., LANGFORD, P. R. & RYCROFT, A. N. (2002) Actinobacillus pleuropneumoniae serotype 1 carrying the defined aroA mutation is fully avirulent in the pig. Research in Veterinary Science 72, 163-167. PubMed ID 12027598

BOSSE, J. T., JANSON, H., SHEEHAN, B. J., BEDDEK, A. J., RYCROFT, A. N., KROLL, J. S. & LANGFORD, P. R. (2002) Actinobacillus pleuropneumoniae: pathobiology and pathogenesis of infection. Microbes & Infection 4, 225-235. PubMed ID 11880056

RYCROFT, A. N. & GARSIDE, L. H. (2000) Actinobacillus species and their role in animal disease. Vet Journal 159, 18-36. PubMed ID 10640409

CULLEN, J. M. & RYCROFT, A. N. (1994) Phagocytosis by pig alveolar macrophages of Actinobacillus pleuropneumoniae serotype 2 mutant strains defective in haemolysin II (ApxII) and pleurotoxin (ApxIII). Microbiology 140, 237-244. PubMed ID 8180688

MACDONALD, J. & RYCROFT, A. N. (1993) Actinobacillus pleuropneumoniae haemolysin II is secreted from Escherichia coli by A. pleuropneumoniae pleurotoxin secretion gene products. FEMS Microbiol Lett 109, 317-322. PubMed ID 8339922

MACDONALD, J. & RYCROFT, A. N. (1992) Molecular cloning and expression of ptxA, the gene encoding the 120-kilodalton cytotoxin of Actinobacillus pleuropneumoniae serotype 2. Infect Immun 60, 2726-2732. PubMed ID 1612740

RYCROFT, A. N., WILLIAMS, D., MCCANDLISH, I. A. & TAYLOR, D. J. (1991) Experimental reproduction of acute lesions of porcine pleuropneumonia with a haemolysin-deficient mutant of Actinobacillus pleuropneumoniae. Vet Rec 129, 441-443. PubMed ID 1781136

RYCROFT, A. N., WILLIAMS, D., CULLEN, J. M. & MACDONALD, J. (1991) The cytotoxin of Actinobacillus pleuropneumoniae (pleurotoxin) is distinct from the haemolysin and is associated with a 120 kDa polypeptide. J Gen Microbiol 137, 561-568. PubMed ID 2033378

RYCROFT, A. N. & CULLEN, J. M. (1990) Complement resistance in Actinobacillus (Haemophilus) pleuropneumoniae infection of swine. Am J Vet Res 51, 1449-1453. PubMed ID 2396792

Andrew devises and supervises laboratory-based undergraduate, masters' and PhD projects.  He lectures in Microbiology and Infectious Diseases for the undergraduate BVetMed, BSc Bioveterinary Science and BSc Veterinary Nursing and has been awarded the Jim Bee teaching prize on four occasions. He oversees the coverage of infectious diseases teaching to veterinary students.

He has successfully guided 16 post-graduate students, as primary supervisor, to complete their PhD, and acted as co-supervisor and external examiner for many more - nationally and internationally. He is current Chairman of the BVetMed III Exam Board.

Andrew established the procedures for the veterinary microbiology diagnostic lab at the RVC.  He continues to advise on clinical veterinary microbiology to veterinary practitioners and researchers throughout the UK.

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