Journal of Microbiology

Journal Article

Antibiofilm effect of biofilm-dispersing agents on clinical isolates of Pseudomonas aeruginosa with various biofilm structures: Soo-Kyoung Kim , Xi-Hui Li , Hyeon-Ji Hwang , Joon-Hee Lee; J. Microbiol. 2018;56(12):902-909. Published online October 25, 2018; DOI: https://doi.org/10.1007/s12275-018-8336-4

Abstract: Pseudomonas aeruginosa, an opportunistic human pathogen, causes many biofilm-mediated chronic infections. In this study, biofilm structures of various clinical strains of P. aeruginosa isolated from hospitalized patients were examined and their influence on the biofilm-dispersing effects of chemicals was investigated. The clinical isolates formed structurally distinct biofilms that could be classified into three different groups: 1) mushroom-like, 2) thin flat, and 3) thick flat structures. A dispersion of these differently structured biofilms was induced using two biofilm-dispersing agents, anthranilate and sodium nitroprusside (SNP). Although both SNP and anthranilate could disperse all types of biofilms, the thick flat biofilms were dispersed less efficiently than the biofilms of other structures. This suggests that biofilm-dispersing agents have higher potency on the biofilms of porous structures than on densely packed biofilms.

Characterization of Quinolone-Resistant Clinical Isolates of Escherichia coli in Korea: Yoojung Oh , Seohyung Park , Misun Ha , Yeonhee Lee; J. Microbiol. 2002;40(2):98-103.

Abstract: Twenty-eight clinical isolates of Escherichia coli, composed of thirteen norfloxacin resistant isolates (MIC of >16 ug/ml), one intermediately resistant isolate (MIC of 8 ug/ml), and fourteen susceptible isolates (MIC of <4 ug/ml), were randomly selected to study the norfloxacin resistance mechanism and phylogeny in clinical isolates in Korea. Eleven norfloxacin resistant isolates and one susceptible isolate were multi-drug resistant (MDR). Every norfloxacin resistant isolate with MIC higher than 32 ug/ml had the same three mutations: Ser83->Leu and Asp87->Asn or Tyr in GyrA and Ser80->Ile in ParC. Whereas a resistant isolate with MIC of 16 ug/ml had three mutations but Asp87 in GyrA was replaced with Gly instead of Asn. The intermediately resistant isolate had the same two mutations in GyrA but a different mutation in ParC, Glu84->Lys. Among the susceptible isolates, two isolates with MIC of 4 ug/ml had one mutation: Ser83->Leu in GyrA, and no mutation was found in the susceptible isolates. Resistant isolates showed higher efflux activity than the susceptible ones, with random amplification of polymorphic DNA (RAPD), six susceptible isolates form a separate group from the rest of the isolates.

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