| Abstract | Studije o antimikrobnoj osjetljivosti i sustavnom praćenju Ralstonia pickettii u bolničkom okruženju vrlo su ograničene jednako kao i istraživanja okolišnih izolata R. pickettii, posebice na većem broju izolata. Ispitivanje rezistencije R. pickettii na antibiotike nije standardizirano. Ovo ispitivanje provedeno je s ciljem utvrđivanja svojstava i osjetljivosti na antibiotike izolata R. pickettii s područja Republike Hrvatske. U petogodišnjem periodu prikupljen je 81 izolat s dva geografska područje RH, iz različitih industrijskih sustava za farmaceutsku ultračistu vodu i laboratorijsku pročišćenu vodu. Osjetljivost na antibiotike ispitana je E-testom i disk difuzijskim testom. Lančanom reakcijom polimeraze ispitano je prisustvo gena blaOXA22 i blaOXA60 za oksacilinaze, gena blaIMP, blaVIM, i blaNDM za metalo-β-laktamazu, gena blaOXA48 za hidrolizirajuću karbapenemazu, gena armA, rmtA, rmtB, rmtD za 16S rRNA metil-transferaze i gena aac(3’)-II, aac(6’)-Ib, aph(3′)-Ia, ant(2′′) za aminoglikozid-modificirajuće enzime. Metodom konjugacije nije dokazan prijenos gena rezistencije na meropenem i gentamicin s R. pickettii na primatelja E. coli J53 koja je bila osjetljiva na ta dva antibiotika, a rezistentna na natrijev azid. Gel elektroforezom u pulsirajućem polju dobivena je velika srodnost izolata i identificirana su tri glavna klastera koji sadrže podklastere. Dobiveni su različiti profili osjetljivosti/otpornosti. Većina izolata bila je otporna na kolistin, aztreonam, ertapenem, aminoglikozide i meropenem. Visoke stope rezistencije uočene su i kod tikarcilin/klavulanske kiseline, tikarcilina, amoksicilin/klavulanske kiseline i ampicilina. S druge strane ispitivani izolati su pokazali visoke stope osjetljivosti na tetracikline, tigeciklin, trimetoprim-sulfametoksazol, imipenem, cefepime, cefaleksin, cefoksitin, cefotaksim, piperacilin-tazobaktam, ciprofloksacin, ceftazidime i piperacilin. Modificirani Hodge test bio je pozitivan u 51,9% izolata. Gen blaOXA22 je otkriven u 37,0% izolata, a gen blaOXA60 u 80,3% izolata. Tako visoka prisutnost gena blaOXA22 i blaOXA60 ukazuje kako "sterilna" voda može predstavljati golemi rezervoar gena rezistencije koji se, onda primjenom iste, mogu prenijeti u kliničko okruženje i predstavljati prijetnju uspješnom liječenju infekcija. Nisu detektirani geni za metalo-β-laktamaze, karbapenemaze, najčešće 16S rRNA metil-transferaze niti za aminoglikozid-modificirajuće enzime. U izolatima je dokazano prisustvo endotoksina. Dokazana je pokretljivost plivanja i trzanja, proizvodnja izvan stanične polimerne supstance te sposobnost proizvodnje biofilma. R. pickettii treba shvatiti ozbiljno kao mogućeg uzročnika nozokomijalnih infekcija kako bi se osigurala odgovarajuća terapija, spriječio razvoj rezistentnih sojeva i smanjila mogućnost njezinog preživljavanja u sustavima za čistu, ultra čistu i laboratorijsku pročišćenu vodu. |
| Abstract (english) | Studies on antimicrobial susceptibility and systematic monitoring of Ralstonia pickettii in the hospital environment are very limited, as well as research on environmental isolates of R. pickettii, especially on a larger number of isolates. The aim of this study was to determine the properties and antibiotic susceptibility of R. pickettii isolates from the Republic of Croatia. In a five-year period, 81 isolates were collected from two geographical areas of the Republic of Croatia, from different industrial systems for pharmaceutical ultrapure water and laboratory purified water. Susceptibility to antibiotics was tested by E-test and disk diffusion test. The presence of genes blaOXA22 and blaOXA60 for oxacillinases, genes blaIMP, blaVIM, and blaNDM for metallo-β-lactamase, gene blaOXA48 for hydrolyzing carbapenemase, genes armA, rmtA, rmtB, rmtD for 16S rRNA methyltransferases and genes aac(3')-II, aac(6')-Ib, aph(3′)-Ia, ant(2′′) for aminoglycoside-modifying enzymes was tested by polymerase chain reaction. The modified Hodge test was positive in 51.9% of the isolates. The blaOXA22 gene was detected in 37.0%, and blaOXA60 gene in 80.3% isolates. Genes for metallo-β-lactamases, carbapenemases, the most common 16S rRNA methyl-transferases and aminoglycoside modifying enzymes were not detected. The conjugation method did not detected transfer of resistance genes to the meropenem and gentamicin from R. pickettii to the recipient E. coli J53, which was sensitive to those two antibiotics and resistant to sodium azide. Pulsed-field gel electrophoresis showed high relatedness of the isolates and three major clusters containing subclusters were identified. Different susceptibility/resistance profiles were detected. Most isolates were resistant to colistin, aztreonam, ertapenem, aminoglycosides and meropenem. High rates of resistance were also observed for ticarcillin/clavulanic acid, ticarcillin, amoxicillin/clavulanic acid and ampicillin. On the other hand, the tested isolates showed high susceptibility rates to tetracycline, tigecycline, trimethoprim-sulfamethoxazole, imipenem, cefepime, cephalexin, cefoxitin, cefotaxime, piperacillin-tazobactam, ciprofloxacin, ceftazidime and piperacillin. High presence of blaOXA22 and blaOXA60 genes indicates that "sterile" water can represent a large reservoir of resistance genes. When such water is used in clinical setting, it could pose a threat to the successful treatment of infections. The presence of endotoxin was detected. Swimming and twitching motility, the production of extracellular polymeric substances and the ability to produce biofilms were confirmed. R. pickettii should be taken seriously as a possible cause of nosocomial infections to ensure adequate therapy, to prevent the development of resistant strains and to reduce the survival of R. pickettii in clean and ultra clean water systems. |
