Pseudo-Outbreak of Actinomyces graevenitzii Associated with Bronchoscopy

Abstract

Outbreaks and pseudo-outbreaks of infection related to bronchoscopy typically involve Gram-negative bacteria, Mycobacterium species or Legionella species. We report an unusual bronchoscopy-related pseudo-outbreak due to Actinomyces graevenitzii. Extensive epidemiological and microbiological investigation failed to identify a common source. Strain typing revealed that the cluster was comprised of heterogeneous strains of A. graevenitzii. A change in laboratory procedures for Actinomyces cultures was coincident with the emergence of the pseudo-outbreak, and we determined that A. graevenitzii isolates more readily adopted a white, dry, molar tooth appearance on anaerobic colistin nalidixic acid (CNA) agar which likely facilitated its detection and identification in bronchoscopic specimens. This unusual pseudo-outbreak was related to frequent requests of bronchoscopists for Actinomyces cultures combined with a change in microbiology laboratory practices. Actinomyces graevenitzii is infrequently identified in clinical specimens, and its pathogenicity is not well defined. A. graevenitzii is a component of the oropharyngeal microbiota and has been reported to cause pneumonia, lung abscesses, osteitis of the jaw, and bacteremia (1-8). In early December 2013, an increase in the recovery of A. graevenitzii from specimens from patients who underwent bronchoscopy was noted by microbiology and infection control staff. Our investigation revealed that the cluster of A. graevenitzii isolates represented a pseudo-outbreak associated with a change in laboratory practices. MATERIALS AND METHODS Setting.A 1,500-bed tertiary care university-affiliated teaching hospital was the setting for this study.Epidemiological investigation. The microbiology laboratory's computerized database was queried to obtain the number of bronchoscopy cultures performed, the number of Actinomyces cultures ordered on bronchoscopy specimens, and the number of those cultures ordered that were positive for Actinomyces from January 2011 through December 2013. Medical records of patients whose bronchoscopy specimens yielded Actinomyces were reviewed, and the following variables were recorded: date of bronchoscopy, results of bronchoscopic specimen cultures for routine respiratory pathogens and for Actinomyces, bronchoscope used, bronchoscopist, endoscopy personnel involved in the procedure, procedure room number, and medications administered during bronchoscopy procedures. Only three bronchoscopes were routinely used, and almost all bronchoscopies were performed in procedure room 3. Therefore, we focused our investigation on room 3, the three bronchoscopes, and the "wash room" in which all bronchoscopes and endoscopes undergo highlevel disinfection using one of three automated endoscope reprocessors (AERs) (DSDs Medivators, Minneapolis, MN). Findings of cytologic examination and bronchial biopsy specimens were also recorded.Environmental sources of samples collected for culture in the endoscopy suite included unopened bottles of lidocaine, atomizer, cotton ball...

Actinomyces and Related Organisms in Human Infections

“…This was also the case in another study, where four A. graevenitzii isolates were obtained from similar pulmonary sources (25). In a recent epidemiological investigation, A. graevenitzii proved to be the predominant species identified in Actinomyces-positive bronchoscopy cultures (198). The 18 case patients had abnormalities on chest radiography but no biopsy findings typical of pulmonary actinomycosis; 12 of the patients were positive for A. graevenitzii, 3 were positive for A. odontolyticus, 1 was positive for both A. graevenitzii and A. odontolyticus, and 2 were positive for unspecified Actinomyces species.…”

“…The 18 case patients had abnormalities on chest radiography but no biopsy findings typical of pulmonary actinomycosis; 12 of the patients were positive for A. graevenitzii, 3 were positive for A. odontolyticus, 1 was positive for both A. graevenitzii and A. odontolyticus, and 2 were positive for unspecified Actinomyces species. An interesting observation was the significant increase in the number of Actinomyces-positive pulmo-nary specimens after the culture protocol was modified (198). Previously, A. israelii had been identified as the main Actinomyces species recovered in bronchial secretions (13).…”

Efficacy of humidity retention bags for the reduced adsorption and improved cleaning of tissue proteins including prion-associated amyloid to surgical stainless steel surfaces

“…The decontamination procedures currently employed within sterile service departments (SSDs) for the reprocessing of reusable surgical instruments are very efficient against bacterial contamination although not always as effective in tissue protein decontamination or in bacterial decontamination of endoscope channels (Lipscomb et al 2006a;Kovaleva et al 2014;Peaper et al 2015). However, highly hydrophobic proteins such as prions may remain adsorbed to surgical stainless steel (SS) surfaces (Gibbs et al 1994;Lipscomb et al 2006b;Murdoch et al 2006;Herve et al 2010).…”

A Pseudo-Outbreak of <b><i>Pseudomonas putida</i></b> and <b><i>Stenotrophomonas maltophilia</i></b> in a Bronchoscopy Unit

“…Although infectious complications of flexible bronchoscopy are uncommon, outbreaks and pseudo-outbreaks related to bronchoscopy have been reported [3][4][5][8][9][10][11][12][13] . The proper method for high-level disinfection or sterilization of bronchoscopes is well described in current guidelines [1,2,7] .…”

“…Although the risk of endoscopy-related transmission of infection is estimated to be very low, more health care-associated infections are related to contaminated endoscopes than to any other medical device. However, most of the recent outbreaks and pseudo-outbreaks have resulted from contaminated automated endoscope reprocessors (AER) or the use of damaged or malfunctioning bronchoscopes or contaminated equipment, including rinsing tanks, tubing, antibacterial filters on water lines, and cleaning brushes [3][4][5] . Most reports refer to pseudo-outbreaks as the isolation of organisms in bronchoscopy specimens due to colonization or contamination of the bronchoscope rather than true patient-to-patient transmission ('true infection') [5,6] .…”