Virulence factors and other clinically relevant characteristics of Chryseobacterium species
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Date
2008-05
Authors
Van Wyk, Esias Renier
Journal Title
Journal ISSN
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Publisher
University of the Free State
Abstract
English: The genus Chryseobacterium was first proposed in 1994 and consisted of six species, it has since rapidly expanded and currently consists of 36 different species. Most of these species have been proposed within the last 3 years. Bacteria belonging to the genus Chryseobacterium are aerobic, non-sporulating, non-motile, Gram-negative rods which produce a yellow pigment. Chryseobacterium species have been found in a variety of environmental, industrial and clinical surroundings. Several species have already exhibited pathogenic characteristics for different animals and for humans as well. The first aim of this study was to evaluate the potential pathogenesis of 14 Chryseobacterium species by evaluating a variety of known virulence factors (enzymes), to evaluate their antimicrobial resistance patterns as well as to determine their resistance to four commercially available disinfectants. When the production of specific enzymes by the 14 Chryseobacterium species were evaluated, it was found that C. daecheongense, C. joostei, C. shigense, C. soldanellicola, C. taeanense, C. vrystaatense together with C. indologenes which was regarded the standard organism, can be regarded potentially pathogenic. The species most resistant to all of the antimicrobials evaluated, were C. indologenes, C. indoltheticum and C. joostei. The most susceptible to the antimicrobials was C. balustinum. It was also found that it would be best to treat an infection of Chryseobacterium with antimicrobials of the quinolone class or cephem class. The penicillin class would seem to be the least effective. The disinfectant resistance was determined by determining the MIC for each tested disinfectant, with a higher MIC exhibiting more resistance. The species with the highest resistance were C. gleum, C. indologenes and C. joostei. The disinfectants tested were for use either on hard surfaces or on wounds (personal use). From the results obtained disinfectants for use on hard surfaces are more effective than those meant for personal use. In conclusion it can be said that C. gleum, C. indologenes and C. joostei may be regarded as the most pathogenic of the 14 Chryseobacterium species evaluated. Chryseobacterium joostei may be less of a threat as it was first isolated from raw milk, which had not yet undergone pasteurization and as such, is less likely to come into contact with the general population. It would seem that C. gleum and C. indologenes however come into contact with people more often as they have been found in or on ill or wounded individuals on several different occasions. The second aim of the study was to evaluate possible degradation of aflatoxin B1 by the 14 Chryseobacterium species. After statistical analysis, it was concluded that no Chryseobacterium species was able to degrade aflatoxin. This study, however contributed to the knowledge on the significance of these bacteria.
Afrikaans: Die genus Chryseobacterium was die eerste keer voorgestel in 1994 en het bestaan uit ses spesies, sedertdien het dit vinnig uitgebrei an bestaan tans uit 36 verskillende spesies. Meeste van hierdie spesies was voorgestel binne die laaste drie jaar. Bakteriëe wat aan die genus Chryseobacterium behoort is aerobies, nie-sporulerende, niebewegende, Gram-negatiewe stawe wat ‘n geel pigment produseer. Chryseobacterium spesies is al gevind in ‘n verskeidendeid natuurlike, industriële en kliniese omgewings. ‘n Paar spesies het alreeds patogeniese eienskappe getoon vir verskillende diere asook vir mense. Die eerste doelstelling van hierdie studie was om die patogeniese potensiaal te evalueer van 14 verskillende Chryseobacterium spesies deur middel van die evaluasie van ‘n verskeidenheid van virulensie faktore (ensieme), om die antimikrobiese weerstand patrone te evalueer, asook hul weerstand teen vier kommersiëel beskikbare ontsmettinsmiddels te evalueer. Toe die produksie van spesifieke ensieme deur die 14 Chryseobacterium spesies ge-evalueer was, was dit gevind dat C. daecheongense, C. joostei, C. shigense, C. soldanellicola, C. taeanense, C. vrystaatense saam met C. indologenes, wat beskou was as die standaard organism, beskou kon word as potensiële patogene. Die spesies wat mees weerstandbiedend was teen die ge-evalueerde antimikrobiese middels was C. indologenes, C. indoltheticum en C. joostei. Die mees vatbare teen die middels was C. balustinum. Dit was ook gevind dat dit die beste sou wees om ‘n infeksie van Chryseobacterium te behandel met antimikrobiese middels van die ‘quinolone’ of ‘cephem’ klas. Die penisillien klas blyk om die minste effektief te wees. Die ontsmettingsmiddel weerstand was bepaal deur die minimum inhibiterende konsentrasie (MIK) vir elke middel te bepaal. ‘n Hoër MIK dui op hoër weerstandbiedendheid. Die spesies met die hoogste weerstand was C. gleum, C. indologenes en C. joostei. Die ge-evalueerde onstmettingsmiddels was vir die gebruik op harde oppervlaktes of op wonde (persoonlike gebruik). Vanaf die resultate verkry, blyk dit asof ontsmettingsmiddels vir gebruik op harde oppervlaktes meer effektief is as die vir gebruik op wonde. In afsluiting kan gesê word dat C. gleum, C. indologenes en C. joostei beskou kan word as die mees patogeniese van die 14 spesies wat ge-evalueer was. Chryseobacterium joostei mag dalk ‘n kleiner bedreiging wees, synde dit die eerste keer in ongepasteuriseerde melk geïsoleer was en dus minder waarskynlik in kontak sal kom met die algemene publiek wat gepasteuriseerde melk drink. Daarenteen blyk dit dat C. gleum en C. indologenes meer gereeld in kontak kom met mense aangesien hulle in verskeie studies reeds gevind is in of op siek of gewonde mense. Die tweede doelstelling van hierdie studie was om die moontlike afbraak van aflatoksien B1 by die 14 Chryseobacterium spesies te ondersoek. Na statistiese analise is dit bevind dat geeneen van die Chryseobacterium spesies in staat was om aflatoksien af te breek nie. Hierdie studie het wel bygedra tot die kennis van die belangrikheid van hierdie bacteria.
Afrikaans: Die genus Chryseobacterium was die eerste keer voorgestel in 1994 en het bestaan uit ses spesies, sedertdien het dit vinnig uitgebrei an bestaan tans uit 36 verskillende spesies. Meeste van hierdie spesies was voorgestel binne die laaste drie jaar. Bakteriëe wat aan die genus Chryseobacterium behoort is aerobies, nie-sporulerende, niebewegende, Gram-negatiewe stawe wat ‘n geel pigment produseer. Chryseobacterium spesies is al gevind in ‘n verskeidendeid natuurlike, industriële en kliniese omgewings. ‘n Paar spesies het alreeds patogeniese eienskappe getoon vir verskillende diere asook vir mense. Die eerste doelstelling van hierdie studie was om die patogeniese potensiaal te evalueer van 14 verskillende Chryseobacterium spesies deur middel van die evaluasie van ‘n verskeidenheid van virulensie faktore (ensieme), om die antimikrobiese weerstand patrone te evalueer, asook hul weerstand teen vier kommersiëel beskikbare ontsmettinsmiddels te evalueer. Toe die produksie van spesifieke ensieme deur die 14 Chryseobacterium spesies ge-evalueer was, was dit gevind dat C. daecheongense, C. joostei, C. shigense, C. soldanellicola, C. taeanense, C. vrystaatense saam met C. indologenes, wat beskou was as die standaard organism, beskou kon word as potensiële patogene. Die spesies wat mees weerstandbiedend was teen die ge-evalueerde antimikrobiese middels was C. indologenes, C. indoltheticum en C. joostei. Die mees vatbare teen die middels was C. balustinum. Dit was ook gevind dat dit die beste sou wees om ‘n infeksie van Chryseobacterium te behandel met antimikrobiese middels van die ‘quinolone’ of ‘cephem’ klas. Die penisillien klas blyk om die minste effektief te wees. Die ontsmettingsmiddel weerstand was bepaal deur die minimum inhibiterende konsentrasie (MIK) vir elke middel te bepaal. ‘n Hoër MIK dui op hoër weerstandbiedendheid. Die spesies met die hoogste weerstand was C. gleum, C. indologenes en C. joostei. Die ge-evalueerde onstmettingsmiddels was vir die gebruik op harde oppervlaktes of op wonde (persoonlike gebruik). Vanaf die resultate verkry, blyk dit asof ontsmettingsmiddels vir gebruik op harde oppervlaktes meer effektief is as die vir gebruik op wonde. In afsluiting kan gesê word dat C. gleum, C. indologenes en C. joostei beskou kan word as die mees patogeniese van die 14 spesies wat ge-evalueer was. Chryseobacterium joostei mag dalk ‘n kleiner bedreiging wees, synde dit die eerste keer in ongepasteuriseerde melk geïsoleer was en dus minder waarskynlik in kontak sal kom met die algemene publiek wat gepasteuriseerde melk drink. Daarenteen blyk dit dat C. gleum en C. indologenes meer gereeld in kontak kom met mense aangesien hulle in verskeie studies reeds gevind is in of op siek of gewonde mense. Die tweede doelstelling van hierdie studie was om die moontlike afbraak van aflatoksien B1 by die 14 Chryseobacterium spesies te ondersoek. Na statistiese analise is dit bevind dat geeneen van die Chryseobacterium spesies in staat was om aflatoksien af te breek nie. Hierdie studie het wel bygedra tot die kennis van die belangrikheid van hierdie bacteria.
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Keywords
Dissertation (M.Sc. (Microbial, Biochemical and Food Biotechnology))--University of the Freee State, 2008, Gram-negative bacteria, Pathogenic bacteria, Bacteria -- Classification, Virulence (Microbiology), Potential pathogenicity, Degradation, Aflatoxin B1, Antimicrobial resistance, Disinfectant resistance, Virulence factors, Chryseobacterium