An Electronic Network for the Surveillance of Antimicrobial Resistance in Bacterial Nosocomial Isolates in Greece

Article excerpt

Voir page 600 le resume en francais. En la pagina 600 figura un resumen en espanol.

Introduction

Antimicrobial resistance has become a serious public health concern in many parts of the world. Systematic monitoring of such resistance at local, national and international levels is recognized as an integral part of the control strategy by most national and international organizations including WHO (1-4).

Several multicentre surveys conducted in Greece over the last 10 years (5-8) have identified this problem and underlined the need for immediate action. For example, the Greek Ministry of Health and Welfare has addressed this issue by imposing restrictions on the use of newer antimicrobials (third-generation cefalosporins, aztreonam, imipenem and quinolones) in the hospital setting through an audit-based prescription process. To satisfy the urgent need for an efficient surveillance system to monitor the possible impact of this policy, and to study the epidemiology of antimicrobial resistance, we launched a project in 1995 to establish a national network for continuous monitoring of such resistance.

This project is based on the assumption that the routine results of the antimicrobial sensitivity tests performed daily in each clinical laboratory should be considered to be a major resource for resistance surveillance. Since the quality and compatibility of these data are uncertain, our approach has been to work in parallel, establishing access to the data and assessing its quality. To do this we set up a quality control procedure and employed a standardized electronic code and data format in all hospitals, based on WHONET software. The WHONET software was originally devised by the WHO Collaborating Centre for Surveillance of Antibiotic Resistance, Boston, MA, USA, and further developed by WHO in Geneva. WHONET is distributed free by WHO and facilitates the management of antimicrobial sensitivity test results from routine clinical isolates. A full description of the software and its potential has been published elsewhere (9, 10).

In this article we describe the Greek network and present some of the results obtained using it. The results illustrate the positive impact of a national or international surveillance network in preventing and confronting antimicrobial-resistant bacterial diseases. The data presented cover the period January-December 1996.

Materials and methods Participating hospitals

A total of 28 hospital microbiology laboratories in Athens, Pereus, Thessaloniki and various other cities in Greece were asked to participate in the network--the main prerequisite being the availability of a PC installed with WHONET software. All data were entered into the program, if possible on a daily basis. Data entry was done either manually (for hospitals using the disc diffusion method for sensitivity testing) or by automatic download with the aid of BACLINK software (available upon request from Dr J. Stelling, Communicable Disease Surveillance and Response Programme, World Health Organization, Geneva), for hospitals using automatic sensitivity systems. Each laboratory was asked to agree to make available all electronic files for purposes of preparing multicentre reports.

Isolation and identification of pathogenic bacteria

Isolation of pathogenic bacteria from clinical specimens and identification to the species level was performed by standard methods at the microbiology laboratories of each hospital participating in the network.

Sensitivity testing

The sensitivity testing methods used by the participating hospitals were as follows: Kirby--Bauer disc diffusion in 17 hospitals; Sensititre (Sensititre, Salem, NH, USA) in one hospital; Pasco (Difco, Detroit, MI, USA) in 11 hospitals. The zone diameters or minimum inhibitory concentrations (MICs), and not the interpretations of the tests, are entered into WHONET.

Quality control

Escherichia coli (ATCC 25922), Staphylococcus aureus (ATCC 25923) and Pseudomonas aeruginosa (ATCC 27853) strains are used as internal quality controls. …