Is selective digestive decontamination useful in controlling aerobic gram-negative bacilli producing extended spectrum beta-lactamases?
OBJECTIVE
To identify outbreak episodes of either carriage or infection due to extended spectrum beta-lactamases producing aerobic Gram-negative bacilli (AGNB-ESBL); to establish whether AGNB-ESBL, sensitive to tobramycin, become resistant over time; and to evaluate the impact of selective decontamination of the digestive tract (SDD) on abnormal carriage of AGNB-ESBL.


METHODS
All children admitted to the pediatric intensive care unit (PICU) over a 12-month period had biweekly surveillance cultures of throat and rectum and diagnostic cultures when clinically indicated. All AGNB were tested for ESBL, and the positive isolates were sent for molecular typing. The PICU uses SDD (parenteral cefotaxime and enteral polymyxin E/tobramycin) to control abnormal carriage. Patients who had at least one AGNB-ESBL were included in the study.


RESULTS
During the study period, 1,101 children were admitted to the PICU. There were 39 patients (3.5%) with a total of 236 cultures positive for AGNB-ESBL. Twenty-eight patients (2.5%) were carriers, and 11 (1%) had proven infections. Organisms isolated from the first culture were 14 patients with Klebsiella pneumoniae, 8 with Enterobacter cloacae, 7 with Citrobacter freundii, 5 with Klebsiella oxytoca, and 5 with Escherichia coli. In the first sample, 59% of isolates showed tobramycin resistance. Molecular typing confirmed that there were five different strains of K. pneumoniae and that similar strains were not isolated in the same period.


CONCLUSIONS
SDD is an effective measure to control AGNB-ESBL and to avoid outbreak episodes of either carriage or infection. When tobramycin resistance is found, replacing it with another aminoglycoside based on antibiogram may be more effective in achieving AGNB clearance.
Paediatric Intensive Care Unit, Alder Hey Children's Hospital, Liverpool, United Kingdom. francisco@abecasis.name
Francisco
F
Abecasis
Richard E
RE
Sarginson
Steve
S
Kerr
Nia
N
Taylor
Hendrik K F
HK
van Saene
D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000494:pharmacology*; D015373:Bacterial Typing Techniques; D002353:Carrier State; D002648:Child; D004196:Disease Outbreaks / Q000517:prevention & control; D024881:Drug Resistance, Bacterial; D041981:Gastrointestinal Tract / Q000382:microbiology*; D006088:Gram-Negative Aerobic Bacteria / Q000187:drug effects / Q000302:isolation & purification*; D016905:Gram-Negative Bacterial Infections / Q000188:drug therapy / Q000453:epidemiology / Q000382:microbiology; D006801:Humans; D015278:Intensive Care Units, Pediatric; D008826:Microbial Sensitivity Tests; D013997:Time Factors; D014031:Tobramycin / Q000494:pharmacology; D001618:beta-Lactamases / Q000378:metabolism*
D000900:Anti-Bacterial Agents; D001618:beta-Lactamases; D014031:Tobramycin