Critical Care Medicine  |   December 2018
Oropharyngeal Bacterial Colonization after Chlorhexidine Mouthwash in Mechanically Ventilated Critically Ill Patients
Author Notes
  • From Assistance Publique Hôpitaux de Paris Louis Mourier Hospital, Medico-surgical Intensive Care Unit, Colombes, France (B.L.C., J.M., D.D., J.-D.R.); National Institute of Health and Medical Research, Infection Antimicrobials Modelling Evolution, Joint Research Unit 1137, Paris, France (B.L.C., A.-C.M., J.M., T.B.-P., C.B., L.L., D.D., L.M., J.-D.R.); Université Paris Diderot, Infection Antimicrobials Modelling Evolution, Joint Research Unit 1137, Sorbonne Paris Cité, Paris, France (B.L.C., A.-C.M., J.M., T.B.-P., C.B., L.L., D.D., L.M., J.-D.R.); Assistance Publique Hôpitaux de Paris, Louis Mourier Hospital, Microbiology Laboratory, Colombes, France (A.-C.M., T.B.-P., C.B., L.L.,); Assistance Publique Hôpitaux de Paris, Hôpital Bichat, Clinical Research Unit Paris Nord, Paris, France (F.D.); National Institute of Health and Medical Research, Clinical Epidemiology and Economic Evaluation Applied to Vulnerable Populations, Joint Research Unit 1123, Paris, France (F.D.); Université Paris Diderot, Clinical Epidemiology and Economic Evaluation Applied to Vulnerable Populations, Joint Research Unit 1123, Sorbonne Paris Cité, Paris, France (F.D.); and Assistance Publique Hôpitaux de Paris, Hôpital Bichat, Clinical Pharmacology and Toxicology, Paris, France (L.M.).
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    Supplemental Digital Content is available for this article. Direct URL citations appear in the printed text and are available in both the HTML and PDF versions of this article. Links to the digital files are provided in the HTML text of this article on the Journal’s Web site (www.anesthesiology.org).×
  • Submitted for publication March 17, 2018. Accepted for publication August 20, 2018.
    Submitted for publication March 17, 2018. Accepted for publication August 20, 2018.×
  • Address correspondence to Prof. Ricard: Service de Réanimation Médico-Chirurgicale, 178 rue des Renouillers, 92700, Colombes, France. jean-damien.ricard@aphp.fr. Information on purchasing reprints may be found at www.anesthesiology.org or on the masthead page at the beginning of this issue. Anesthesiology’s articles are made freely accessible to all readers, for personal use only, 6 months from the cover date of the issue.
Article Information
Critical Care Medicine / Clinical Science / Critical Care / Infectious Disease / Respiratory System
Critical Care Medicine   |   December 2018
Oropharyngeal Bacterial Colonization after Chlorhexidine Mouthwash in Mechanically Ventilated Critically Ill Patients
Anesthesiology 12 2018, Vol.129, 1140-1148. doi:10.1097/ALN.0000000000002451
Anesthesiology 12 2018, Vol.129, 1140-1148. doi:10.1097/ALN.0000000000002451
Abstract

Editor’s Perspective:

What We Already Know about This Topic:

  • Chlorhexidine is frequently used to reduce oropharyngeal bacterial colonization in mechanically ventilated patients. How effective the drug is remains unclear.

What This Article Tells Us That Is New:

  • Bacterial colonization was evaluated in 30 mechanically ventilated patients before and after application of 0.12% chlorhexidine.

  • Chlorhexidine did not reduce colonization and may, therefore, be less effective than previously assumed.

Background: Oropharyngeal care with chlorhexidine to prevent ventilator-associated pneumonia is currently questioned, and exhaustive microbiologic data assessing its efficacy are lacking. The authors therefore aimed to study the effect of chlorhexidine mouthwash on oropharyngeal bacterial growth, to determine chlorhexidine susceptibility of these bacteria, and to measure chlorhexidine salivary concentration after an oropharyngeal care.

Methods: This observational, prospective, single-center study enrolled 30 critically ill patients under mechanical ventilation for over 48 h. Oropharyngeal contamination was assessed by swabbing the gingivobuccal sulcus immediately before applying 0.12% chlorhexidine with soaked swabs, and subsequently at 15, 60, 120, 240, and 360 min after. Bacterial growth and identification were performed, and chlorhexidine minimal inhibitory concentration of recovered pathogens was determined. Saliva was collected in 10 patients, at every timepoint, with an additional timepoint after 30 min, to measure chlorhexidine concentration.

Results: Two hundred fifty bacterial samples were analyzed and identified 48 pathogens including Streptococci (27.1%) and Enterobacteriaceae (20.8%). Oropharyngeal contamination before chlorhexidine mouthwash ranged from 103 to 107 colony-forming units (CFU)/ml in the 30 patients (median contamination level: 2.5·106 CFU/ml), and remained between 8·105 (lowest) and 3·106 CFU/ml (highest count) after chlorhexidine exposure. These bacterial counts did not decrease overtime after chlorhexidine mouthwash (each minute increase in time resulted in a multiplication of bacterial count by a coefficient of 1.001, P = 0.83). Viridans group streptococci isolates had the lowest chlorhexidine minimal inhibitory concentration (4 [4 to 8] mg/l); Enterobacteriaceae isolates had the highest ones (32 [16 to 32] mg/l). Chlorhexidine salivary concentration rapidly decreased, reaching 7.6 [1.8 to 31] mg/l as early as 60 min after mouthwash.

Conclusions: Chlorhexidine oropharyngeal care does not seem to reduce bacterial oropharyngeal colonization in critically ill ventilated patients. Variable chlorhexidine minimal inhibitory concentrations along with low chlorhexidine salivary concentrations after mouthwash could explain this ineffectiveness, and thus question the use of chlorhexidine for ventilator-associated pneumonia prevention.