Pattern of extended-spectrum beta-lactamase producers in coastal seawater of Northern Portugal after a four-year period

Abstract number: 1134_04_250

Rocha J., Ferreira H.

Objectives:  

Access the presence of extended-spectrum beta-lactamase (ESBL) producers, in coastal seawater of Oporto urban area in 2004 and compare with those obtained in 2000.

Methods:  

Coastal seawater samples were collected monthly, between February and July 2004. Isolates were selected by membrane filtration technique and the filters were placed on Mac Conkey agar and Mac Conkey agar with ceftazidime (5 mg/l) or cefotaxime (2 mg/l). Colonies of lactose fermenters were randomly selected and screened for ESBL production by the double disc synergy test. Identification of the selected strains was achieved by classic biochemical tools and ID 32 GN. Susceptibility to antimicrobial agents was determined according to the NCCLS guidelines. Beta-lactamases were characterized by isoelectric focusing.

Results:  

ESBL producers were found in marine coastal waters of Oporto urban area over the mentioned period of time, in 2004. Actual work, shows a pattern of different types of ESBL and different associations of beta-lactamases, by opposition to the clonal characteristic of ESBL-producing E. coli isolates in 2000.

Conclusion:  

The presence of isolates showing different ESBL and different beta-lactamases association patterns, as expected, in sea coastal water in different dates, seems to indicate distinct epidemiological relationships associated to a persistent, incoming of ESBL producers to the natural environment, providing a track for environmental dissemination of resistant bacteria and genes, that may create a source of transferable traits for emerging pathogens, via natural reservoirs of resistance, relevant in terms of public health and environmental protection.