Folia Medica 61(3): 458-461, doi: 10.3897/folmed.61.e39349
First Report of DHA-1 Producing Enterobacter cloacae Complex Isolate in Bulgaria
expand article infoDobromira I. Dimitrova, Rumyana D. Markovska§, Temenuga J. Stoeva, Petya B. Stankova, Lyudmila B. Georgieva§, Kalina I. Mihova§, Radka P. Kaneva§, Ivan G. Mitov§
‡ Medical University, Varna, Bulgaria§ Medical University, Sofia, Bulgaria
Open Access

The aim of the present study was to reveal the characteristics of an Enterobacter cloacae complex isolate producing DHA-1 AmpC enzyme recovered from a patient hospitalized in St Marina Hospital, Varna.

Materials and methods: Susceptibility testing, conjugation experiments, isoelectric focusing, PCR and sequencing were carrying out.

Results: Of 176 Enterobacter spp. isolates only one isolate was positive for blaDHA. The sequencing revealed the presence of blaDHA-1 and blaCTX-M-3. The antimicrobial susceptibility testing showed higher resistance rates to almost all beta-lactams (ceftazidime, cefotaxime, cefepime, amoxicillinclavulanic acid, piperacillin/tazobactam), tobramycin, gentamycin, trimethoprim/sulphomethoxazole and quinolones (ciprofloxacin and levofloxacin). The isolate was susceptible to imipenem, meropenem and amikacin. The isoelectric focusing showed a band at pI 5.4 without ceftazidime and cefotaxime activity; a band at pI 7.8 with cefoxitin activity and another - with pI 8.4 with cefotaxime activity. Conjugation experiments were successful only for blaCTX-M-3 carrying determinants. 

Conclusions: To the best of our knowledge this is the first report of DHA-1 producing isolate in Bulgaria. The emergence of DHA-1 producing E. cloacae complex demonstrates the possibility for further dissemination of the gene encoding this enzyme. Infectious control measures are needed for the prevention of this phenomenon.

Bulgaria, AmpC, DHA-1, Enterobacter cloacae complex