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Pseudoepidemic from Mycobacterium gordonae due to a contaminated automatic bronchoscope washing machine
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Pseudoepidemic from Mycobacterium gordonae due to a contaminated automatic bronchoscope washing machine To the Editor: Optical fiber bronchoscopes are increasingly used by pneumologists. These devices, which are mandatory for making a Pneumocystis carinii pneumonia diagnosis, allow for rapid and affordable microbiological and histological diagnoses. The high throughput these instruments undergo requires, in order to avoid the cross-contamination of patients, continuous and accurate disinfection procedures, which usually consist of appropriate washing practices and the use of decontaminating machines. The omission of controls needed to validate these disinfection procedures may result in bronchoscope contamination, with the possibility of an outbreak of a pseudoepidemic or, at worst, the transmission among patients of life-threatening diseases.1-5 Nontuberculous mycobacteria, frequent contaminants in water, are considered in the literature as the organisms most difficult to eradicate from invasive diagnostic devices.6,7 We report here on the repeated isolation of Mycobacterium gordonae from outpatients undergoing bronchoscopy for the diagnosis of various pathologies. Materials and Methods In the first 10 months of year 2000, 267 patients underwent a bronchoscopy. The standard operating procedure dictated that, after each use, the bronchoscope be washed with a proteolytic detergent (Proteozim Plus 400; IMS, Pomezia, Roma, Italy), rinsed with tap water, dried, and disinfected with 2% Am J Infect Control 2002;30:196-198. Copyright © 2002 by the Association for Professionals in Infection Control and Epidemiology, Inc. 0196-6553/2002/$35.00 + 0
196
glutaraldehyde for 50 minutes using an automatic device (Disinfector 35100; Richard Wolf GmbH, Knittlingen, Germany) whose disinfecting solution was to be replaced bimonthly. At the end of each work session, the cycle was repeated for 3 hours. The rinsing was conducted automatically using filtered tap water, and the bronchoscope was then stored in a proper cabinet. The water filtering unit (Filterpatrone; Richard Wolf GmbH, Knittlingen, Germany) was sterilized via autoclave at the end of every session and replaced monthly. Bronchial aspirates were used for microscopic (Gram’s stain and auramine-rhodamine) and cultural investigations, both for ordinary bacteria and mycobacteria. Results Out of 267 bronchial aspirate mycobacterial cultures, 16 isolates of scotochromogenic acid-fast bacilli were grown. The isolates, identified at the regional mycobacteria reference center, belonged to the species M gordonae. This finding appeared anomalous because only 1 M gordonae sample was previously isolated from 1368 bronchial aspirates sent to the microbiology laboratory in 7 years. Upon a thorough cultural mycobacterial review of all the fluids involved in the washing procedure, M gordonae was isolated from 2 samples of tap water feeding the washing machine and from the filtering unit, which was not effectively trapping the bacteria present in the water. A subsequent investigation revealed a failure in filter replacement and maintenance. A prompt restoration of the correct procedure resulted in no further isolation of M gordonae. Discussion The resolution of this case of M gordonae pseudoepidemic was facilitated by the common origin (the pneumological ward) of the bronchial aspirates from which M gordonae grew. Nevertheless, this necessitated nearly 3 months of work, and both the microbiology laboratory and the pneumologic units were financially and operationally taxed. Additionally,
letters to the Editor
May 2002 197
expensive cultures and identifications were conducted, and unnecessary antimycobacterial treatments were administered to patients, who were also distressed by the suspicion of having acquired pulmonary tuberculosis. The strict enforcement of correct maintenance measures was sufficient to eliminate the problem. References 1. Wenzel RP, Edmond MB. Tuberculosis infection after bronchoscopy. JAMA 1997;278(13):1073-7. 2. Michele TM, Cronin WA, Graham NM, Dwyer DM, Pope DS, Harrington S, et al. Transmission of Mycobacterium tuberculosis by a fiberoptic bronchoscope. Identification by DNA fingerprinting. JAMA 1997;278(13):1093-5. 3. Nomura K, Ogawa M, Chang B, Miyamoto H, Tanabe T, Taniguchi H, et al. Contamination of a bronchial fiberscope by mycobacteria linked to an automated bronchoscope disinfection machine. J UOEH 2000;22(2):159-65. 4. Reeves DS, Brown NM. Mycobacterial contamination of fiberoptic bronchoscopes. J Hosp Infect 1995;30(suppl):531-6. 5. Segal-Maurer S, Kreiswith BN, Burns JM, Lavie S, Lim M, Urban C, et al. Mycobacterium tuberculosis specimen contamination revisited: the role of laboratory environmental control in a pseudo-outbreak. Infect Control Hosp Epidemiol 1998;19(2):101-5. 6. Jackson J, Leggett JE, Wilson DA, Gilbert DN. Mycobacterium gordonae in fiberoptic bronchoscopes. Am J Infect Control 1996;24(1):19-23. 7. Arnow PM, Bakir M,Thompson K, Bova JL. Endemic contamination of clinical specimens by Mycobacterium gordonae. Clin Infect Dis 2000;31(2):472-6.
Roberto Rossetti, PhDa Patrizia Lencioni, PhDa Florio Innocenti, MDb Enrico Tortoli, PhDc U.O. Microbiologia,a U.O. Pneumologia,b Spedali Riuniti, Pistoia Italy, and Laboratorio di Microbiologiae Virologia-Centro Regionale di Riferimento peri Micobatteric Firenze, Italy
10.1067/mic.2002.122383
Testing for Creutzfeldt-Jakob disease To the Editor: Although known to be extremely rare in humans (ie, one in a million), Creutzfeldt-Jakob disease (CJD) received global attention when it surfaced in England and was labeled as the “mad cow” disease. Not being able to determine which animals were infected with the fatal disease, the health authorities had no choice other than to destroy them all. Nevertheless, there now is concern of a human epidemic since some 900,000 cattle were eaten during the disease’s incubation peri-
od and thereby may have exposed literally millions of people to it. Furthermore, because of the prolonged incubation period, it is possible that the extent of the exposure may not be known for 10 to 20 years.1 It should be understood that the “mad cow” disease is a relatively new variant of the neurological CJD disorder that is known to have been plaguing humans since the 1920s. The organism is smaller than a virus and is not accompanied with an inflammatory reaction once it finds an innocent host. As a result, during its extremely long incubation period in which it is hidden, and figuratively speaking invisible, a carrier may not display any identifiable symptom. Within the past year, the Joint Commission for Accreditation of Healthcare Organizations has reported receiving 2 reports where a total of 14 patients are believed to have been exposed to the fatal brain disorder disease through instruments used during brain surgery.2 Since conventional sterilization techniques have long been known not to be effective against the CJD, the community was confronted with the possibility of having no choice other than throwing away all the instruments used in neurological surgery. With the need for the development of a methodology that would eliminate the implementation of such a drastic and costly measure, the World Health Organization responded with a new set of guidelines for rendering them suitable for reuse. Their recommendations called for the instruments to be immersed in a solution of sodium hydroxide and heating it in a gravitydisplacement sterilizer for 30 minutes. This disinfection process was to be followed by the instruments being cleaned, rinsed in water, and then subjected to routine sterilization. However, because of the hazards and problems associated with the use of sodium hydroxide (ie, human exposure and damage to instruments and sterilizer), the group also suggested 2 other alternate methods using sodium hypochlorite.3 Obviously, the proper decontamination of the instruments is one thing, but the cleaning and the validation of their being suitable for sterilization and subsequent use is another. To assess the effectiveness of disinfection or sterilization procedures, one must consider the inactivation and removal factor (ie, the reduction of infectious units during the disinfection or sterilization process). Therefore, the probability of an instrument remaining capable of transmitting disease depends on the initial degree of contamination and the effectiveness of the decontamination procedures.4
Pseudoepidemic from Mycobacterium gordonae due to a contaminated automatic bronchoscope washing machine To the Editor: Optical fiber bronchoscopes are increasingly used by pneumologists. These devices, which are mandatory for making a Pneumocystis carinii pneumonia diagnosis, allow for rapid and affordable microbiological and histological diagnoses. The high throughput these instruments undergo requires, in order to avoid the cross-contamination of patients, continuous and accurate disinfection procedures, which usually consist of appropriate washing practices and the use of decontaminating machines. The omission of controls needed to validate these disinfection procedures may result in bronchoscope contamination, with the possibility of an outbreak of a pseudoepidemic or, at worst, the transmission among patients of life-threatening diseases.1-5 Nontuberculous mycobacteria, frequent contaminants in water, are considered in the literature as the organisms most difficult to eradicate from invasive diagnostic devices.6,7 We report here on the repeated isolation of Mycobacterium gordonae from outpatients undergoing bronchoscopy for the diagnosis of various pathologies. Materials and Methods In the first 10 months of year 2000, 267 patients underwent a bronchoscopy. The standard operating procedure dictated that, after each use, the bronchoscope be washed with a proteolytic detergent (Proteozim Plus 400; IMS, Pomezia, Roma, Italy), rinsed with tap water, dried, and disinfected with 2% Am J Infect Control 2002;30:196-198. Copyright © 2002 by the Association for Professionals in Infection Control and Epidemiology, Inc. 0196-6553/2002/$35.00 + 0
196
glutaraldehyde for 50 minutes using an automatic device (Disinfector 35100; Richard Wolf GmbH, Knittlingen, Germany) whose disinfecting solution was to be replaced bimonthly. At the end of each work session, the cycle was repeated for 3 hours. The rinsing was conducted automatically using filtered tap water, and the bronchoscope was then stored in a proper cabinet. The water filtering unit (Filterpatrone; Richard Wolf GmbH, Knittlingen, Germany) was sterilized via autoclave at the end of every session and replaced monthly. Bronchial aspirates were used for microscopic (Gram’s stain and auramine-rhodamine) and cultural investigations, both for ordinary bacteria and mycobacteria. Results Out of 267 bronchial aspirate mycobacterial cultures, 16 isolates of scotochromogenic acid-fast bacilli were grown. The isolates, identified at the regional mycobacteria reference center, belonged to the species M gordonae. This finding appeared anomalous because only 1 M gordonae sample was previously isolated from 1368 bronchial aspirates sent to the microbiology laboratory in 7 years. Upon a thorough cultural mycobacterial review of all the fluids involved in the washing procedure, M gordonae was isolated from 2 samples of tap water feeding the washing machine and from the filtering unit, which was not effectively trapping the bacteria present in the water. A subsequent investigation revealed a failure in filter replacement and maintenance. A prompt restoration of the correct procedure resulted in no further isolation of M gordonae. Discussion The resolution of this case of M gordonae pseudoepidemic was facilitated by the common origin (the pneumological ward) of the bronchial aspirates from which M gordonae grew. Nevertheless, this necessitated nearly 3 months of work, and both the microbiology laboratory and the pneumologic units were financially and operationally taxed. Additionally,
letters to the Editor
May 2002 197
expensive cultures and identifications were conducted, and unnecessary antimycobacterial treatments were administered to patients, who were also distressed by the suspicion of having acquired pulmonary tuberculosis. The strict enforcement of correct maintenance measures was sufficient to eliminate the problem. References 1. Wenzel RP, Edmond MB. Tuberculosis infection after bronchoscopy. JAMA 1997;278(13):1073-7. 2. Michele TM, Cronin WA, Graham NM, Dwyer DM, Pope DS, Harrington S, et al. Transmission of Mycobacterium tuberculosis by a fiberoptic bronchoscope. Identification by DNA fingerprinting. JAMA 1997;278(13):1093-5. 3. Nomura K, Ogawa M, Chang B, Miyamoto H, Tanabe T, Taniguchi H, et al. Contamination of a bronchial fiberscope by mycobacteria linked to an automated bronchoscope disinfection machine. J UOEH 2000;22(2):159-65. 4. Reeves DS, Brown NM. Mycobacterial contamination of fiberoptic bronchoscopes. J Hosp Infect 1995;30(suppl):531-6. 5. Segal-Maurer S, Kreiswith BN, Burns JM, Lavie S, Lim M, Urban C, et al. Mycobacterium tuberculosis specimen contamination revisited: the role of laboratory environmental control in a pseudo-outbreak. Infect Control Hosp Epidemiol 1998;19(2):101-5. 6. Jackson J, Leggett JE, Wilson DA, Gilbert DN. Mycobacterium gordonae in fiberoptic bronchoscopes. Am J Infect Control 1996;24(1):19-23. 7. Arnow PM, Bakir M,Thompson K, Bova JL. Endemic contamination of clinical specimens by Mycobacterium gordonae. Clin Infect Dis 2000;31(2):472-6.
Roberto Rossetti, PhDa Patrizia Lencioni, PhDa Florio Innocenti, MDb Enrico Tortoli, PhDc U.O. Microbiologia,a U.O. Pneumologia,b Spedali Riuniti, Pistoia Italy, and Laboratorio di Microbiologiae Virologia-Centro Regionale di Riferimento peri Micobatteric Firenze, Italy
10.1067/mic.2002.122383
Testing for Creutzfeldt-Jakob disease To the Editor: Although known to be extremely rare in humans (ie, one in a million), Creutzfeldt-Jakob disease (CJD) received global attention when it surfaced in England and was labeled as the “mad cow” disease. Not being able to determine which animals were infected with the fatal disease, the health authorities had no choice other than to destroy them all. Nevertheless, there now is concern of a human epidemic since some 900,000 cattle were eaten during the disease’s incubation peri-
od and thereby may have exposed literally millions of people to it. Furthermore, because of the prolonged incubation period, it is possible that the extent of the exposure may not be known for 10 to 20 years.1 It should be understood that the “mad cow” disease is a relatively new variant of the neurological CJD disorder that is known to have been plaguing humans since the 1920s. The organism is smaller than a virus and is not accompanied with an inflammatory reaction once it finds an innocent host. As a result, during its extremely long incubation period in which it is hidden, and figuratively speaking invisible, a carrier may not display any identifiable symptom. Within the past year, the Joint Commission for Accreditation of Healthcare Organizations has reported receiving 2 reports where a total of 14 patients are believed to have been exposed to the fatal brain disorder disease through instruments used during brain surgery.2 Since conventional sterilization techniques have long been known not to be effective against the CJD, the community was confronted with the possibility of having no choice other than throwing away all the instruments used in neurological surgery. With the need for the development of a methodology that would eliminate the implementation of such a drastic and costly measure, the World Health Organization responded with a new set of guidelines for rendering them suitable for reuse. Their recommendations called for the instruments to be immersed in a solution of sodium hydroxide and heating it in a gravitydisplacement sterilizer for 30 minutes. This disinfection process was to be followed by the instruments being cleaned, rinsed in water, and then subjected to routine sterilization. However, because of the hazards and problems associated with the use of sodium hydroxide (ie, human exposure and damage to instruments and sterilizer), the group also suggested 2 other alternate methods using sodium hypochlorite.3 Obviously, the proper decontamination of the instruments is one thing, but the cleaning and the validation of their being suitable for sterilization and subsequent use is another. To assess the effectiveness of disinfection or sterilization procedures, one must consider the inactivation and removal factor (ie, the reduction of infectious units during the disinfection or sterilization process). Therefore, the probability of an instrument remaining capable of transmitting disease depends on the initial degree of contamination and the effectiveness of the decontamination procedures.4