Quinolone resistance mechanisms among third-generation cephalosporin resistant isolates of Enterobacter spp. in a Bulgarian university hospital

• Published in: Infection and drug resistance Vol. 12; pp. 1445 - 1455
• Main Authors: Markovska, Rumyana, Stoeva, Temenuga, Dimitrova, Dobromira, Boyanova, Lyudmila, Stankova, Petya, Mihova, Kalina, Mitov, Ivan
• Format: Journal Article
• Language: English
• Published: New Zealand Dove Medical Press Limited 01.01.2019; Dove; Dove Medical Press
• Subjects: Alleles; Antibacterial agents; Beta lactamases; Bulgaria; Cefepime; Cephalosporins; Enterobacter spp; Epidemiology; Genes; Imipenem; Medical equipment industry; Meropenem; Original Research; PMQR; quinolone resistance; Tazobactam; Bulgaria; United States; PMQR; Bulgaria; quinolone resistance; Enterobacter spp
• ISSN: 1178-6973; 1178-6973
• DOI: 10.2147/IDR.S204199

There have been no reports in Bulgaria about quinolone resistance determinants among spp. To investigate plasmid and chromosomal quinolone resistance rates among 175 third-generation cephalosporin resistant spp. isolates (167 complex and eight isolates) collected at a university hospital in Varna, Bulgaria, as well as to reveal their association with ESBL/AmpC production and a carriage of specific plasmid replicon types. PCR, isoelectric focusing, replicon typing, sequencing, and epidemiology typing were carried out. A high level of combined third-generation cephalosporin and quinolone resistant spp. was found - 79.4%. The ESBL production rate was 87%, consisting mainly of CTX-M-15 among complex (in 76%) and CTX-M-3 among (in 88%). Plasmid mediated quinolone resistance (PMQR) determinants were identified in 57% of the isolates. The most commonly detected PMQR determinants were (90%), consisting mainly of (in 61%), and (in 27%) of the isolates. Both alleles were transferred with CTX-M-15 genes; transconjugants showed HI2 replicons (for positive transconjugants) and were non-typeable (for ). One spp. isolate produced and were detected in single isolates only. A, and AB genes were not found. was associated with CTX-M-15 production, and was linked to CTX-M-3. Alterations in 83 and 87 positions of in quinolone-resistance determining regions, and 80 position of were detected in high level quinolone resistant isolates. Among all the spp. isolates tested, one predominant clone A was identified (53%). Our data showed the necessity of more prudent use of quinolones and third-generation cephalosporins, because of the risk of promoting dissemination, and selection of multiple resistance determinants (ESBL, PMQR) among spp. isolates in Bulgaria.