Razlikovanje mikobakterij iz sklopa Mycobacterium (M.) avium in M. abscessus ter določanje občutljivosti za najpomembnejša protimikrobna sredstva

Truden, Sara (author), Starčič Erjavec, Marjanca (mentor), Žolnir Dovč, Manca (comentor)

Netuberkulozne mikobakterije (NTM) so okoljski oportunistični patogeni. So nesporogeni, negibljivi, aerobni bacili, ki imajo v celični steni mikolno kislino, katera je odgovorna za večino lastnosti mikobakterijskih celic. Mikobakteriozo najpogosteje povzročajo mikobakterije iz sklopa Mycobacterium avium (MAC) in Mycobacterium abscessus (MABSC). Taksonomija znotraj sklopov MAC in MABSC se je v zadnjem času zelo spreminjala zaradi vpeljave novih molekularnih tehnik, ki omogočajo razlikovanje vrst. Tako je sklop M. avium pridobil novo vrsto Mycobacterium chimaera, ki je bila pred tem prepoznana kot vrsta Mycobacterium intracellulare in sklop M. abscessus je razpadel na tri podvrste. Ker so NTM okoljski mikroorganizmi, so konstantno izpostavljeni različnim koncentracijam razkužil in drugim protimikrobnim sredstvom in posledično so NTM razvile različne mehanizme odpornosti. Makrolidi in aminoglikozidi so najpogosteje uporabljeni antibiotiki za zdravljenje okužb, ki jih povzročajo bakterije iz sklopov MAC in MABSC. Z diagnostičnim kompletom GenoType NTM-DR (Hain Lifescience GmbH) smo analizirali 139 izolatov mikobakterij, pridobljenih iz Nacionalne zbirke mikobakterijskih izolatov Laboratorija za mikobakterije Klinike Golnik, ki pripadajo sklopu MABSC in vrsti M. intracellulare. Preverili smo, katera podvrsta sklopa MABSC je najbolj pogosta v Sloveniji in koliko analiziranih izolatov je s to metodo prepoznanih kot M. chimaera. Hkrati smo pridobili informacije o prisotnosti mutacij v genih, ki posredujejo odpornost proti makrolidom in aminoglikozidom. Poleg tega smo preizkusili metodo ERIC-PCR in preverili ali razlikuje izolate in seve med seboj. Ugotovili smo, da 48,5 % analiziranih izolatov pripada vrsti M. chimaera in da je M. abscessus subsp. abscessus najpogosteje prisotna podvrsta sklopa MABSC. Večino naših izolatov sklopa MABSC je odpornih proti makrolidom, medtem ko so vsi izolati sklopov MAC in MABSC občutljivi za aminoglikozide. Pokazali smo, da metoda ERIC-PCR razlikuje med izolati in sevi mikobakterij sklopov MAC in MABSC.

• Language: Slovenian
• Keywords: mikobakterije, netuberkulozne mikobakterije, Mycobacterium avium, Mycobacterium abscessus, molekularne metode, identifikacija bakterij, ERIC-PCR, GenoType NTM-DR, protimikrobne učinkovine, antibiotiki
• Work type: Master's thesis/paper
• Typology: 2.09 - Master's Thesis
• Organization: BF - Biotechnical Faculty
• Publisher: [S. Truden]
• Year: 2017
• PID: 20.500.12556/RUL-94335
• UDC: 579.873.2:579.61:57.083
• COBISS.SI-ID: 4806776
• Publication date in RUL: 28.07.2017

Secondary language

• Language: English
• Title: Diferentiation of Mycobacterium (M.) avium complex and M. abscessus complex and determination of susceptibility against most important antimicrobial drugs

Abstract

Nontuberculous mycobacteria (NTM) are environmental opportunistic pathogens. They are non-sporulating, non-mobile, aerobic bacteria. As all mycobacteria, NTM have in the cell wall mycolic acid, which impart mycobacteria with unique properties. Mycobacteria from Mycobacterium avium complex (MAC) and Mycobacterium abscessus complex (MABSC) are the most frequent cause of mycobacteriosis in the world. In the last few years taxonomy in MAC and MABSC was rapidly changing due to new molecular methods that are able to differentiate between species. New techniques are able to identify Mycobacterium chimaera that was previously recognized as Mycobacterium intracellulare and also differentiate subspecies of MABSC. Due to their natural habitat, NTM are constantly exposed to various concentrations of antimicrobial drugs and other chemicals and consequently they had developed different resistance mechanisms. Macrolides and aminoglycosides are frequently used drugs to treat MAC and MABSC infections. One hundred and thirty-nine Slovenian mycobacteria isolates obtained from National collection of mycobacterial isolates from Klinika Golnik that belong to MAC and MABSC were analysed. GenoType NTM-DR (Hain Lifescience GmbH) was used to differentiate M. intracellulare from M. chimaera and subspecies of MABSC. Not only species identification but also information about mutation in genes that confer resistance against macrolides and aminoglycosides, was obtained. ERIC-PCR was tested on some isolates of MAC and MABSC for its ability to differentiate different isolates and strains. Results showed that 48,5% of previously identified M. intracellulare were actually recognised as M. chimaera and that M. abscessus subsp. abscessus is the most frequent subspecies of MABSC. Most of the MABSC isolates were resistant to macrolides, however none of the isolates of MAC and MABSC had mutations in genes for aminoglycoside resistance. Results obtained with ERIC-PCR showed that the method is able to differentiate isolates and strains of MAC and MABSC.

• Keywords: mycobacteria, nontuberculous mycobacteria, Mycobacterium avium, Mycobacterium abscessus, molecular methods, identification of bacteria, ERIC-PCR, GenoType NTM-DR, antimicrobial drugs, antibiotics