Étude de la résistance des entérobactéries aux céphalosporines de troisième génération dans les hôpitaux de Sfax, Tunisie (1999–2005)

Epidemiological study of Enterobacteriaceae resistance to colistin in Sfax (Tunisia)

OBJECTIVES

The authors had for aim to monitor Enterobacteriaceae resistance to colistin, during 6 years (2005-2010), and to study the epidemiology of Enterobacteriaceae resistant strains isolated in the Sfax region (Tunisia).

DESIGN

This retrospective study was carried out in the microbiology laboratory, at the Habib Bourguiba teaching hospital in Sfax. All strains of colistin resistant Enterobacteriaceae isolated from patients were studied.

RESULTS

One hundred and twenty one strains of colistin resistant Enterobacteriaceae were isolated from 93 patients. Klebsiella pneumoniae was the most frequent species (60.2%), followed by Enterobacter cloacae (26.9%), and Escherichia coli (12.9%). Thirteen strains (E. cloacae) were heteroresistant to colistin. Eighty one isolates (87.1%) were resistant to third generation cephalosporins. The rate of resistance to colistin ranged from 0.09% for E. coli to 1.2% for K. pneumoniae, and 1.5% for E. cloacae. A progressively increasing colistin resistance was observed for K. pneumoniae. Most resistant strains were isolated from urine in the urology department. Previous exposure to colistin was reported in 59.2% of patients. Pulsed field gel electrophoresis typing revealed different clones.

CONCLUSIONS

Colistin resistance in Enterobacteriaceae is a worrying phenomenon in Sfax. It is related to polyclonal diffusion. Continuous epidemiological monitoring and a rational use of colistin are necessary to limit the spreading of these colistin resistant strains and to maintain this antibiotic's effectiveness.

Nosocomial infections and fever of unknown origin in pediatric hematology/oncology unit: a retrospective annual study

BACKGROUND

pediatric hematology/oncology patients are faced with an increased risk of nosocomial infections (NIs) that vary in different populations and different institutions with considerable morbidity and mortality. This study was undertaken to assess the frequency and patterns of NIs in 1564 pediatric patients and to determine the prevalence of causative organisms and their antimicrobial sensitivity.

METHODS

a retrospective analysis was made in the patients admitted between January 2007 and January 2008 to the pediatric hematoloy/oncology unit of Mansoura University, Egypt. The 1564 patients showed 2084 admissions and 27 092 inpatient days. The Centers for Disease Control and Prevention criteria were used as a standard definition for NI.

RESULTS

the overall rate of NIs in all patients and neutropenic patients was 8.6 and 25.3 per 1000 patient-days respectively. The frequent sites of NIs were blood stream (42.7%), the respiratory system (25.3%), the urinary system (22.2%) and the central nervous system (9.8%), whereas nosocomial fever of unknown origin constituted 52.9% of cases. The incidence of NIs was significantly higher during neutropenic days (P<0.001). Gram-positive organisms represented 64.5% of pathogens (Staphylococci 71.5%, Streptococci 16%, and pneumococci 7%), and Gram-negative organisms represented 30% (E. coli 48.6%, Klebsiella 15.7%, Pseudomonas 35.7%, and C. albicans 5.5%). Positive cultures were more frequent in summer (July to September). Susceptibility of isolated organisms was relatively low (cefoperazone/sulbactam 49.9%, amikacin 35.9%, imipenem/cilastin 34.4%, cefoperazone 33.6%, and vancomycin 36.5%). Methicillin-resistant S. aureus, extended spectrum beta lactamase and vancomycin resistant enterococci represented 30%, 45% and 75% of isolated S. aureus, Gram-negative organisms and Enterococci, respectively.

CONCLUSIONS

blood stream infection and fever of unknown origin are the most common nosocomial infections in pediatric hematology/oncology patients with a higher risk during neutropenic days. Isolated organisms are multi-drug resistant, predominantly Gram-positive pathogens with a high incidence of methicillin-resistant S. aureus, extended spectrum beta lactamase and vancomycin resistant enterococci organisms.