Selective digestive decontamination for control of outbreaks in the ICU

Selective digestive decontamination for control of outbreaks in the ICU

SELECTIVE DIGESTIVE DECONTAMINATION FOR C O N T R O L OF O U T B R E A K S I N T H E I C U • BRUN-BUISSON, MD Digestive tract decontamination (DD) h...

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SELECTIVE DIGESTIVE DECONTAMINATION FOR C O N T R O L OF O U T B R E A K S I N T H E I C U • BRUN-BUISSON,

MD

Digestive tract decontamination (DD) has been suggested as a control measure for outbreaks caused by m u l t i r e s i s t a n t (MR) bacteria for a long time [1]. This proposal stemmed from the observations made during several outbreaks caused by MR enterobacteriaceae (such as Klebsiella or Proteus spp.) of a high rate of intestinal colonization of patients by organisms causing the outbreak [2, 3]. By ~>the intestinal tract of patients, it was hoped t h a t a major reservoir of outbreak strains would be reduced, contributing to the control of such outbreaks, when associated with traditional infection control measures. There are 2 published and one unpublished studies t h a t support the use of DD in this situation. All three studies report on the use of DD for control of outbreaks due to Klebsiella harbouring the recently described extended spectrum [~-lactamases of the various TEM and SHV type. Different DD regimens have been used in each of the 3 studies, with different designs in evaluation. In the first reported s t u d y [4], an <>regimen, previously used in neutropenic patients, including Polymixin E / n e o m y c i n and nalidixic acid, was administered orally or via a nasogastric tube to ICU patients of > 48 hrs stay. This was a controlled study, with historical and concomittant controls, where colonization and infection rates with MR Klebsiella were examined, first during a 3-months control period (Group 1) with no intervention except for rein-

Medical Intensive Care Unit, Henri Mondor Hospital, F-94010, Cr6teil.

forcement of infection control measures (handwashing and gloving, isolating or grouping infected and colonized patients), and secondly during a 3-months test period during which patients of expected ICU stay of > 48 hrs were randomized to no prophylaxis (Group 2) or prophylaxis with the above regimen (Group 3). The regimen was administered from admission to discharge from the ICU and no systemic antibiotic prophylaxis nor oropharyngeal decontamination was used. There was no difference among the three groups in severity on admission and characteristics of patients, duration of intubation, length of ICU stay, mortality, overall incidence of nosocomial infections, and systemic antibiotics received. There was however a sharp reduction in the incidence of both intestinal colonization and clinical colonization/infection rates of patients in group 3 as compared to group 1. Intestinal colonization rate was higher in group 2 t h a n in group 3, b u t lower t h a n in group 1. This was interpreted as the consequence of the decreased colonization rate in group 3, reducing the reservoir of colonized patients and the risk of transmission of the MR strains to the concurrent control group ((( cross-over effect >~). The incidence of clinically detected colonization/infections was reduced from 9% in group I to 6% and 0 in groups 2 and 3 (Table I), respectively. Following the use of DD, there was no f u r t h e r case of colonization/infection with the outbreak strains during a subsequent 4 months-period. A small outbreak recurred a few months later, following readmission of a previously colonized patient, which was again controlled by the use of DD in colonized patients.

1re c o n f e r e n c e d e c o n s e n s u s e u r o p C e n n e e n r # a n i m a t i o n - 5 4 9 Table I Intestinal colonization and clinical infection~colonization with MR K. pneumoniae before and during intestinal decontamination (£)13) trial From Brun-Buisson et at. [4] Control Group 1 122 Patients Studied (n) Nb with, n (%) 24 (19.6) intestinal colonization positive clinical samples 11 (9)

DD trial Control Group 2

DD Group 3

50

35

5 (1o) 3 (6)

i 0

A major finding of t h a t study was to show t h a t the use of DD in the major ICU involved was associated with a sharp decrease in the n u m b e r of total MR isolates from other areas in the hospital, where several cases h a d occurred as a consequence of t r a n s f e r of patients from the study ICU to other ICUs or wards. Introduction of the same regimen in another surgical ICU which provided a large part of the residual overall n u m b e r of cases in the hospital resulted in the elimination of the outbreak in the hospital for the subsequent 4 months period. However, several outbreaks have recurred in the hospital since t h a t time, involving the above mentioned two ICUs. These are likely due to the reintroduction of such strains in the hospital, since t h e y are now endemic in several hospitals of the Paris area. The other published study (Taylor and Oppenheim, 1991) describes the use of SDD during a similar outbreak due to MR K. pneumoniae in a much smaller unit (8 beds), and in an uncontrolled fashion. SDD (Polymixin, Tobramycin) was used after a 3-months outbreak when other infection control measures (including restriction of admissions to the unit and of antibiotic usage) were found to have failed. However, several steps were t a k e n successively during this control period, and the time lag between the last step (ICU closed, isolation of infected/colonized patients) and the implementation of SDD is short (1 month). During the 3 months before SDD, there were 8 colonized/infected patients, and no f u r t h e r case during the subsequent 2-months SDD period. Unfortunately, no follow-up is described after the end of the SDD period. Similarly to the preceding study, a high rate of increased intestinal colonization with G r a m positive cocci (mainly Enterococci) was recorded in patients receiving SDD (58% acquired colonization with Enterococci).

The third study is unpublished (Jarlier et al., submitted). It differs m a r k e d l y from the preceding two studies, in t h a t it used erythromycin base as a decontamination regimen. The incidence of MR Klebsiella was surveyed during a 3years period in a 2,300 bed University hospital where erythromycin was administered to all patients admitted to a surgical ICU (where MR K. pneumoniae Were most prevalent) during the last 2 years of the study. During the first year (no erythromycin), prevalence studies showed intestinal colonization rates with MR K. pneumoniae of 40% surgical ICU patients. The rates of intestinal colonization and clinical colonization/infections decreased from 40% and 15.6% to 5.3 and 3.6%, respectively after implementation of erythromycin (Table II). Some MR strains highly resistant to erythromycin were found in the feces, and about 30% of patients carried isolates of GNB highly resistant to erythromycin in their intestinal tract. Other u n i t s have used similar decontamination with erythromycin base during outbreaks of MR Klebsiella, with apparent success.

Table II Incidence of intestinal colonization and clinical infection~colonization with MR K. pneumoniae before and during intestinal decontamination with erythromycin in a surgical ICU. From Jarlier al aL (submitted) During DD Before DD (June 86-June 87) (July 87-June 89) Patients studied (n) n (%) with positive: stool cultures clinical specimens

224

483

35 (15.6)

31 (6.4) 23 (4.8)

Prevalence study showed a 40% intestinal carriage rate of MR strains.

The experience summarized above, although limited, would suggest t h a t intestinal decontamination can be a useful adjunct to traditional infection control m e a s u r e s to help control outbreaks of m u l t i r e s i s t a n t Enterobacteriaceae. However, follow-up data after the use of SDD are limited, and only provided in one study. The selection in the digestive tract of bacteria intrinsically resistant to the regimen used is almost inevitable, which might cause problems with protracted use of DD and favors its restricted use to short periods of time in association to close microbiologic monitoring. Acquisition of resistance during DD should be reduced by the use of a combination regimen of drugs (effective in the digestive tract on the MR strains), if available. R~an. Urg., 1992, 1 (3 bis), 548-550

- 5 5 0 - I re conf6rence de consensus europ6enne en r6animation

References [1] SELDEN R., LEE S., WANG W.L., BENNETTJ.V., EICKNOFFT . C . Nosocomial Klebsiella infection: intestinal colonization as a reservoir. Ann. Intern. Med., 1971, 74, 657-64. [2] SCHABERGD.R., WEINSTEIN R.A., STAMM W.E. - Epidemics of nosocomial urinary tract infections caused by multiply-resistant gram-negative bacilli: epidemiology and control. J. Infect. Dis., 1976, 133, 363-66. [3] WEINSTEINR.A., KABINS S.A. - Strategies for prevention and control of multiple-resistant nosocomial infection. Am. J. Med., 1981, 70, 449-54. [4] BRUN-BUISSON C., LEGRAND P., RAUSS A. et al. - Intestinal decontamination for control of nosocomial multiresistant

mill

R6an. Urg., 1992, 1 (3 bis), 548-550

gram-negative bacilli: Study of an outbreak in an intensive care unit. Ann. Intern. Med., 1989, 110, 873-81. [5] OLASENERH.A., VOLLAARD E.J., VAN SAENE H.K. - Long-term prophylaxis of infection by selective decontamination in leukopenia and in mechanical ventilation. Rev. Infect. Dis., 1987, 9, 295-328. [6] TAYLOR M.E., OPPENHEIM B.A. - Selective decontamination of the gastro-intestinal tract as an infection control measure. J. Hosp. Inf., 1991, 17, 271-278. [7] JARLIER V., ROUBY J.J., NICOLAS M.H. et al. - Outbreak of K. pneumoniae producing extended-spectrum I~-Iactamases: control in intensive care unit by gut decontamination (Submitted).