Journal of Antimicrobial Chemotherapy (1992) 30, 73-87
A controlled trial of selective decontamination of the digestive tract in intensive care and its effect on nosocomial infection R. Winter", H. Humphreys*, A. Pick6, A. P. MacGowan6, S. M. Wmarts" and D. C. E. Speller4
Nosocomial infection is a major problem in intensive therapy units (ITUs) and a significant cause of mortality. Selective decontamination of the digestive tract (SDD) has been advocated as a means to reduce ITU morbidity and mortality. Ninety-one patients in a general ITU underwent SDD, consisting of topical polymyxin E, tobramycm and amphotericin B administered throughout the unit stay together with parenteral ccftazidimc for the first three days, and were compared with 84 historical and 92 contemporaneous control patients who were treated conventionally. Twenty-seven historical and 32 contemporaneous control patients developed unit-acquired infections, in comparison with only three patients in the SDD group (P 5 white cells/high power field > 10' cfu/mL of PPM (2* purulent discharge inflammation
' These criteria are common to all groups. ' The number in parentheses indicates the number of criteria that must be attained for a positive diagnosis of infection; BAL, broncho-alveolar lavage; PPM, potentially pathogenic micro-organisms.
was decontaminated by polymyxin E 100 mg, tobramycin 80 mg and amphotericin B 500 mg administered 6-hourly via the nasogastric tube. Intravenous ceftazidime, 50mg/kg/day in three divided doses, was administered to patients receiving SDD during the first three days only of ITU stay. Clinical assessment All patients were assessed daily throughout their ITU stay for evidence of infection (see Table I for diagnostic criteria). Patients were assessed on admission according to a sepsis score (Elebute & Stoner, 1983) and injury severity score (Baker et al., 1980) where appropriate, and daily by an APACHE II score (Knaus et al, 1985) and for sepsis syndrome (Bone et al, 1991). Infection was classified as primary (present on admission or diagnosed within 48 h of admission) or secondary (occurring after this period) and assigned to one of six diagnostic groups according to denned criteria (Table I). Clinical specimens Specimens (in addition to those required for microbiological surveillance) were taken to diagnose specific infections when indicated. All blood culture isolates were evaluated by a medical microbiologist for clinical significance. All patients in whom the clinical criteria for diagnosing pneumonia were met were investigated by broncho-alveolar lavage (BAL) as previously described (Thorpe et al, 1987). Specimens containing more than two epithelial cells per high power field on microscopy were considered contaminated and therefore not likely to allow a reliable diagnosis of lower respiratory tract infection. Microbiological surveillance Screening specimens (Ledingham et al, 1988) were obtained from patients within 6 h of admission to the ITU (and before the first dose of antibiotics), thrice weekly thereafter
Downloaded from http://jac.oxfordjournals.org/ at Freie Universitaet Berlin on May 7, 2015
Soft tissue
two temperature spikes > 38-S°C in 24 h white cell count > 12 or < 4 x 10*/L
76
R. Winter et aJ.
(at least 2 h after administration of topical antibiotics) while the patient was in the ITU and, finally, four days after discharge to a general ward. All specimens were processed (within 3 h of being taken) as previously described (Ledingham et a/., 1988) to detect the presence of potentially pathogenic micro-organisms (PPMs) including Staphylococcus aureus, Streptococcus pneumoniae, Haemophilus influenzas, Moraxella catarrhalis, aerobic Gram-negative bacilli (AGNB) and yeasts. Colonization was defined as the presence of the same PPM in two successive samples taken from the same site. Throat swabs, tracheal aspirates and rectal swabs were also cultured on horse blood agar containing either 4 mg/L of tobramycin or 4 mg/L of ceftazidime. AGNBs recovered from the antibiotic-containing media were subsequently identified to species and tested for their sensitivity to a range of antibiotics.
Approval was obtained from the Bristol and Weston Health Authority Ethics Committee. Statistical analysis The clinical and laboratory results were analysed with the Minitab Statistical Package. Data were analysed, as appropriate, by analysis of variance or by Kruskall-Wallis tests. When Kruskall-Wallis tests indicated significant differences the Mann-Whitney U-test was used to identify inter-group differences. The Chi-squared test was used to analyse incidence data. Statistical significance was inferred when P
A controlled trial of selective decontamination of the digestive tract in intensive care and its effect on nosocomial infection R. Winter", H. Humphreys*, A. Pick6, A. P. MacGowan6, S. M. Wmarts" and D. C. E. Speller4
Nosocomial infection is a major problem in intensive therapy units (ITUs) and a significant cause of mortality. Selective decontamination of the digestive tract (SDD) has been advocated as a means to reduce ITU morbidity and mortality. Ninety-one patients in a general ITU underwent SDD, consisting of topical polymyxin E, tobramycm and amphotericin B administered throughout the unit stay together with parenteral ccftazidimc for the first three days, and were compared with 84 historical and 92 contemporaneous control patients who were treated conventionally. Twenty-seven historical and 32 contemporaneous control patients developed unit-acquired infections, in comparison with only three patients in the SDD group (P 5 white cells/high power field > 10' cfu/mL of PPM (2* purulent discharge inflammation
' These criteria are common to all groups. ' The number in parentheses indicates the number of criteria that must be attained for a positive diagnosis of infection; BAL, broncho-alveolar lavage; PPM, potentially pathogenic micro-organisms.
was decontaminated by polymyxin E 100 mg, tobramycin 80 mg and amphotericin B 500 mg administered 6-hourly via the nasogastric tube. Intravenous ceftazidime, 50mg/kg/day in three divided doses, was administered to patients receiving SDD during the first three days only of ITU stay. Clinical assessment All patients were assessed daily throughout their ITU stay for evidence of infection (see Table I for diagnostic criteria). Patients were assessed on admission according to a sepsis score (Elebute & Stoner, 1983) and injury severity score (Baker et al., 1980) where appropriate, and daily by an APACHE II score (Knaus et al, 1985) and for sepsis syndrome (Bone et al, 1991). Infection was classified as primary (present on admission or diagnosed within 48 h of admission) or secondary (occurring after this period) and assigned to one of six diagnostic groups according to denned criteria (Table I). Clinical specimens Specimens (in addition to those required for microbiological surveillance) were taken to diagnose specific infections when indicated. All blood culture isolates were evaluated by a medical microbiologist for clinical significance. All patients in whom the clinical criteria for diagnosing pneumonia were met were investigated by broncho-alveolar lavage (BAL) as previously described (Thorpe et al, 1987). Specimens containing more than two epithelial cells per high power field on microscopy were considered contaminated and therefore not likely to allow a reliable diagnosis of lower respiratory tract infection. Microbiological surveillance Screening specimens (Ledingham et al, 1988) were obtained from patients within 6 h of admission to the ITU (and before the first dose of antibiotics), thrice weekly thereafter
Downloaded from http://jac.oxfordjournals.org/ at Freie Universitaet Berlin on May 7, 2015
Soft tissue
two temperature spikes > 38-S°C in 24 h white cell count > 12 or < 4 x 10*/L
76
R. Winter et aJ.
(at least 2 h after administration of topical antibiotics) while the patient was in the ITU and, finally, four days after discharge to a general ward. All specimens were processed (within 3 h of being taken) as previously described (Ledingham et a/., 1988) to detect the presence of potentially pathogenic micro-organisms (PPMs) including Staphylococcus aureus, Streptococcus pneumoniae, Haemophilus influenzas, Moraxella catarrhalis, aerobic Gram-negative bacilli (AGNB) and yeasts. Colonization was defined as the presence of the same PPM in two successive samples taken from the same site. Throat swabs, tracheal aspirates and rectal swabs were also cultured on horse blood agar containing either 4 mg/L of tobramycin or 4 mg/L of ceftazidime. AGNBs recovered from the antibiotic-containing media were subsequently identified to species and tested for their sensitivity to a range of antibiotics.
Approval was obtained from the Bristol and Weston Health Authority Ethics Committee. Statistical analysis The clinical and laboratory results were analysed with the Minitab Statistical Package. Data were analysed, as appropriate, by analysis of variance or by Kruskall-Wallis tests. When Kruskall-Wallis tests indicated significant differences the Mann-Whitney U-test was used to identify inter-group differences. The Chi-squared test was used to analyse incidence data. Statistical significance was inferred when P
