Isolation of Microbial Strains Producing ß-Lactamases with Extended Spectrum from Hospital Environment

Roxana Moldovan, Monica Licker, Mihaela Crãciunescu, and Crenguta Boer

Department of Microbiology, University of Medicine and Pharmacy, Timisoara, Romania

Corresponding author: Roxana Moldovan
    Calea Bogdãnetilor, no.54,
    RO-1900, Timisoara
    Romania
    Telephone: (+40) 56 142 454
    Fax number: (+40) 56 192 101
    E-mail: microbiolog@gmx.net

CEJOEM 2000, Vol.6. No.2-3.:176-182

Key words:
Newborns, gram-negative rods, BLSE

Abbreviations:
BLSE = ß-lactamase with extended spectrum
CTX = cefotaxime
CAZ = ceftazidime
ATM = aztreonam
KgnToNtA = phenotype resistance to aminoglycosides (kanamycin, gentamicin, tobramycin, netilmicin, amikacin)

Abstract:
256 strains of gram-negative bacilli were isolated from various pathological samples collected from mothers and newborns hospitalized in a department of obstetrics and gynecology. The antibiotic susceptibility of the strains was determined by the disk diffusion method. The aim of the study was to identify the strains that were resistant to ß-lactamine due to production of ß-lactamase with extended spectrum (BLSE), as well as to other mechanisms (penicilinase, cephalosporinase producers). Three BLSE strains (E. coli, Enterobacter cloacae and Klebsiella oxytoca) were found, all of them isolated from premature newborns. As this type of enzyme detection is of high microbiological importance, new sensitive and specific methods accessible to any laboratory are permanently searched for. In the simple susceptibility tests made by the disk diffusion method, BLSE strains show a characteristic “champagne stopper” pattern (inhibition area between the amoxicillin + clavulanic acid, cefotaxime, ceftazidime and aztreonam drugs).

Received: 31 July 2000
Accepted: 30 October 2000

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