- Email: [email protected]
From ‘Legionellosis acquired through a dental unit’ to ‘Was Legionellosis acquired through a dental unit?’
204
Letters to the Editor / Journal of Hospital Infection 96 (2017) 201e206
hospital after the dental unit visit. Due to the length of time (13 days according to Lundholm) spent by the patient in the legionella-positive room, it remains plausible that this was the source of the patient’s infection. Nosocomial cases of Legionnaires’ disease may be very complex to investigate and require a number of special considerations. Public health professionals and clinicians should consider recent findings from whole genome sequencing studies which have the potential to enhance future investigations. Conflict of interest statement None declared. Funding sources None.
References [1] Petti S. Did a patient acquire Legionella pneumophila from the cup filler of a dental unit or did a patient infected with L. pneumophila contaminate the cup filler? J Hosp Infect 2017;96(2):201e2. [2] Schonning C, Jernberg C, Klingenberg D, Andersson S, Pa ¨a ¨ja ¨rvi A, Almet E, et al. Legionellosis acquired through a dental unit: a case study. J Hosp Infect 2017;96(1):89e92. [3] Bartram, Chartier Y, Lee JV, Pond K, Surman-Lee S. Legionella and the prevention of legionellosis. Geneva: WHO; 2007. [4] Egan JR, Hall IM, Lemon DJ, Leach S. Modeling Legionnaires’ disease outbreaks: estimating the timing of an aerosolized release using symptom-onset dates. Epidemiology 2011;22:188e98. [5] Den Boer JW, Bruin JP, Verhoef LP, Van der Zwaluw K, Jansen R, Yzerman EP. Genotypic comparison of clinical Legionella isolates and patient-related environmental isolates in The Netherlands, 2002e2006. Clin Microbiol Infect 2008;14:459e66. [6] Collins S, Stevenson D, Walker J, Bennett A. Evaluation of Legionella real-time PCR against traditional culture for routine and public health testing of water samples. J Appl Microbiol 2016 Dec 2 [Epub ahead of print]. In Press. [7] Florentin A, Lizon J, Asensio E, Forin J, Rivier A. Water and surface microbiologic quality of point-of-use water filters: a comparative study. Am J Infect Control 2016;44:1061e2. [8] David S, Afshar B, Mentasti M, Ginevra C, Podglajen I, Harris SR, et al. Seeding and establishment of Legionella pneumophila in hospitals; implications for genomic investigations of nosocomial Legionnaires’ disease. Clin Infect Dis 2017 Feb 17 [Epub ahead of print]. http://dx.doi.org/10.1093/cid/cix153.
S. Collins J. Walker* Biosafety, Air and Water Microbiology Group, Public Health England, Porton Down, UK * Corresponding author. Address: Public Health England, Porton Down, Salisbury SP4 0JG, UK. Tel.: þ44 (0)1980 612643. E-mail address: [email protected] (J. Walker) Available online 23 March 2017
From ‘Legionellosis acquired through a dental unit’ to ‘Was Legionellosis acquired through a dental unit?’
Sir, Scho ¨nning and colleagues reported the case of a man with diagnosis of leukaemia admitted to hospital to undergo bone marrow transplantation who underwent a dental check-up and high-dose chemotherapy and developed Legionnaires’ disease in the following days. The authors entitled their case report ‘Legionellosis acquired through a dental unit’ [1]. I showed that it was not possible to confirm whether the patient acquired Legionella pneumophila from a contaminated dental unit or whether the patient, already infected with L. pneumophila, contaminated the dental unit water system [2]. The authors in their reply correctly stated that L. pneumophila transmission from water systems to a person is the most usual route of spread and is most likely true for the reported fatal case of Legionnaires’ disease at the hospital under investigation, where there was a history of legionellae in the water system [3]. Thus, the authors themselves did not confirm whether the source of L. pneumophila infection to the inpatient was the dental unit water system of the hospital or whether there was a different source in the hospital itself. In addition, Collins and Walker, who initially stated that there was evidence to refute my hypothesis of retrograde contamination e although I only suggested that this hypothesis, as in a previous suspected case, could not be ruled out e suggested that the two hypotheses presented were plausible and that it was not possible to exclude a third scenario that the patient contracted Legionnaires’ disease from another source in the hospital after the dental unit visit, in line with the reply of Scho ¨nning and colleagues to my letter [4,5]. All these elements, considered together, further obscured the initial statement of Legionnaires’ disease acquired through a dental unit, since the chickeneegg dilemma actually could not be ruled out and a third hypothesis emerged that there could be alternative sources of L. pneumophila inside the hospital. For these reasons, the case reported by Scho ¨nning and colleagues might have been better entitled ‘Was Legionellosis acquired through a dental unit?’ Conflict of interest statement None declared. Funding sources None.
References http://dx.doi.org/10.1016/j.jhin.2017.03.022 Crown Copyright ª 2017 Published by Elsevier Ltd on behalf of The Healthcare Infection Society. All rights reserved.
[1] Scho ¨nning C, Jernberg C, Klingenberg D, Andersson S, Pa ¨a ¨ja ¨rvi A, Alm E, et al. Legionellosis acquired through a dental unit e a case study. J Hosp Infect 2017;96(1):89e92. [2] Petti S. Did a patient acquire Legionella pneumophila from the cup filler of a dental unit or did a patient infected with L. pneumophila contaminate the cup filler? J Hosp Infect 2017;96(2):201e2.
Letters to the Editor / Journal of Hospital Infection 96 (2017) 201e206 [3] Scho ¨nning C, Lundholm P, Lytsy B. Reply from the authors and part of the investigation team. J Hosp Infect 2017;96(2):202e3. [4] Petti S. The chickeneegg dilemma: Legionnaires’ disease and retrograde contamination of dental unit waterlines. Infect Control Hosp Epidemiol 2016;37:1258e60. [5] Collins S, Walker J. Legionnaires’ disease from a dental unit. Chicken and egg or a different source entirely? J Hosp Infect 2017;96(2):203e4.
S. Petti* Department of Public Health and Infectious Diseases, Sapienza University, Rome, Italy * Corresponding author. Address: Sanarelli Building, Department of Public Health and Infectious Diseases, Sapienza University, Piazzale Aldo Moro 5, I-00185, Rome, Italy. Tel./fax: þ39 06 4991 4667. E-mail address: [email protected] Available online 13 April 2017 http://dx.doi.org/10.1016/j.jhin.2017.04.011 ª 2017 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.
Improvement in the management of patients with Clostridium difficile associated diarrhoea following changes to the wording of laboratory reports
Sir, Clinical manifestations of Clostridium difficile infection (CDI) range from asymptomatic colonization through mild diarrhoea to life-threatening pseudomembranous colitis. Management of patients with potential CDI is implemented based on clinical findings combined with laboratory testing. At Royal Berkshire NHS Foundation Trust (RBFT), diarrhoeal stool samples from hospital patients (Bristol stool chart type 5e7, not attributable to any underlying clinical condition or medication) above 2 years of age are tested for C. difficile [1,2].
205
From 2012 to 2015, initial screening using a glutamate dehydrogenase (GDH) immunoassay (EIA) test was performed at RBFT. If negative, a report was issued stating: ‘Clostridium difficile NOT detected. CDI is very unlikely.’ If the GDH EIA test was positive, a toxin EIA test was performed; if positive, a report was issued stating: ‘Toxin-producing Clostridium difficile DETECTED. CDI is likely to be present.’ Where the GDH EIA test was positive but the toxin EIA test was negative, a polymerase chain reaction (PCR) test was performed and the issued report stated: ‘Toxin-producing Clostridium difficile detected by PCR. Patient may have transmission potential. CDI could be present, please exercise clinical judgement.’ Anecdotally, healthcare workers (HCWs) at RBFT found the above report wording confusing. A two-part audit was performed to examine the effect of the wording of laboratory reports on the management of CDI. In April and May 2013 (Time Point 1), a questionnaire was circulated amongst HCWs on the wards. Participants were presented with the three possible laboratory reports generated as above, and asked whether the patient should be treated for CDI and whether they should be isolated; in each case, a simple ‘yes’ or ‘no’ answer was required. In addition, inpatients from April 2013 and March 2014 (Time Point 1) with GDH EIA- and PCR-positive results were identified and healthcare records were reviewed. Data were entered into a spreadsheet and analysed, and management was compared with accepted local guidelines. In 2015, the wording of laboratory reports was simplified. If the GDH EIA test was negative, the issued report stated: ‘Clostridium difficile NOT detected.’ If the GDH EIA and toxin EIA tests were positive, or the GDH EIA and PCR tests were positive, the issued report stated: ‘Toxin-producing Clostridium difficile DETECTED.’ Once this change was established, both parts of the audit were repeated between August and March 2015 (Time Point 2). At Time Points 1 and 2, there were 65 and 58 responses, respectively. The proportion of survey respondents giving the correct answer regarding management of C. difficile-positive and -negative patients before and after the change in report wording was compared using a two-tailed Chi-squared test (Table I). At Time Points 1 and 2, there were 52 and 57 patients eligible for inclusion, respectively, with sufficient information for analysis for 27 and 37 patients, respectively. At Time Point 2, 95% of patients required antibiotic treatment for CDI, compared with 52% at Time Point 1. At Time Points 1 and 2, treatment compliant with local guidelines was
Table I Comparison of percentage of correct survey responses before and after changes in report wording Clostridium difficile positive
Correct responses at Time Point 1 (%) Correct responses at Time Point 2 (%) Chi-squared test P-value
Clostridium difficile negative
Treat?
Isolate?
Treat?
Isolate?
86 86 0.00 0.99
93 100 4.65 0.03
86 98 6.03 0.01
83 84 0.04 0.83
Letters to the Editor / Journal of Hospital Infection 96 (2017) 201e206
hospital after the dental unit visit. Due to the length of time (13 days according to Lundholm) spent by the patient in the legionella-positive room, it remains plausible that this was the source of the patient’s infection. Nosocomial cases of Legionnaires’ disease may be very complex to investigate and require a number of special considerations. Public health professionals and clinicians should consider recent findings from whole genome sequencing studies which have the potential to enhance future investigations. Conflict of interest statement None declared. Funding sources None.
References [1] Petti S. Did a patient acquire Legionella pneumophila from the cup filler of a dental unit or did a patient infected with L. pneumophila contaminate the cup filler? J Hosp Infect 2017;96(2):201e2. [2] Schonning C, Jernberg C, Klingenberg D, Andersson S, Pa ¨a ¨ja ¨rvi A, Almet E, et al. Legionellosis acquired through a dental unit: a case study. J Hosp Infect 2017;96(1):89e92. [3] Bartram, Chartier Y, Lee JV, Pond K, Surman-Lee S. Legionella and the prevention of legionellosis. Geneva: WHO; 2007. [4] Egan JR, Hall IM, Lemon DJ, Leach S. Modeling Legionnaires’ disease outbreaks: estimating the timing of an aerosolized release using symptom-onset dates. Epidemiology 2011;22:188e98. [5] Den Boer JW, Bruin JP, Verhoef LP, Van der Zwaluw K, Jansen R, Yzerman EP. Genotypic comparison of clinical Legionella isolates and patient-related environmental isolates in The Netherlands, 2002e2006. Clin Microbiol Infect 2008;14:459e66. [6] Collins S, Stevenson D, Walker J, Bennett A. Evaluation of Legionella real-time PCR against traditional culture for routine and public health testing of water samples. J Appl Microbiol 2016 Dec 2 [Epub ahead of print]. In Press. [7] Florentin A, Lizon J, Asensio E, Forin J, Rivier A. Water and surface microbiologic quality of point-of-use water filters: a comparative study. Am J Infect Control 2016;44:1061e2. [8] David S, Afshar B, Mentasti M, Ginevra C, Podglajen I, Harris SR, et al. Seeding and establishment of Legionella pneumophila in hospitals; implications for genomic investigations of nosocomial Legionnaires’ disease. Clin Infect Dis 2017 Feb 17 [Epub ahead of print]. http://dx.doi.org/10.1093/cid/cix153.
S. Collins J. Walker* Biosafety, Air and Water Microbiology Group, Public Health England, Porton Down, UK * Corresponding author. Address: Public Health England, Porton Down, Salisbury SP4 0JG, UK. Tel.: þ44 (0)1980 612643. E-mail address: [email protected] (J. Walker) Available online 23 March 2017
From ‘Legionellosis acquired through a dental unit’ to ‘Was Legionellosis acquired through a dental unit?’
Sir, Scho ¨nning and colleagues reported the case of a man with diagnosis of leukaemia admitted to hospital to undergo bone marrow transplantation who underwent a dental check-up and high-dose chemotherapy and developed Legionnaires’ disease in the following days. The authors entitled their case report ‘Legionellosis acquired through a dental unit’ [1]. I showed that it was not possible to confirm whether the patient acquired Legionella pneumophila from a contaminated dental unit or whether the patient, already infected with L. pneumophila, contaminated the dental unit water system [2]. The authors in their reply correctly stated that L. pneumophila transmission from water systems to a person is the most usual route of spread and is most likely true for the reported fatal case of Legionnaires’ disease at the hospital under investigation, where there was a history of legionellae in the water system [3]. Thus, the authors themselves did not confirm whether the source of L. pneumophila infection to the inpatient was the dental unit water system of the hospital or whether there was a different source in the hospital itself. In addition, Collins and Walker, who initially stated that there was evidence to refute my hypothesis of retrograde contamination e although I only suggested that this hypothesis, as in a previous suspected case, could not be ruled out e suggested that the two hypotheses presented were plausible and that it was not possible to exclude a third scenario that the patient contracted Legionnaires’ disease from another source in the hospital after the dental unit visit, in line with the reply of Scho ¨nning and colleagues to my letter [4,5]. All these elements, considered together, further obscured the initial statement of Legionnaires’ disease acquired through a dental unit, since the chickeneegg dilemma actually could not be ruled out and a third hypothesis emerged that there could be alternative sources of L. pneumophila inside the hospital. For these reasons, the case reported by Scho ¨nning and colleagues might have been better entitled ‘Was Legionellosis acquired through a dental unit?’ Conflict of interest statement None declared. Funding sources None.
References http://dx.doi.org/10.1016/j.jhin.2017.03.022 Crown Copyright ª 2017 Published by Elsevier Ltd on behalf of The Healthcare Infection Society. All rights reserved.
[1] Scho ¨nning C, Jernberg C, Klingenberg D, Andersson S, Pa ¨a ¨ja ¨rvi A, Alm E, et al. Legionellosis acquired through a dental unit e a case study. J Hosp Infect 2017;96(1):89e92. [2] Petti S. Did a patient acquire Legionella pneumophila from the cup filler of a dental unit or did a patient infected with L. pneumophila contaminate the cup filler? J Hosp Infect 2017;96(2):201e2.
Letters to the Editor / Journal of Hospital Infection 96 (2017) 201e206 [3] Scho ¨nning C, Lundholm P, Lytsy B. Reply from the authors and part of the investigation team. J Hosp Infect 2017;96(2):202e3. [4] Petti S. The chickeneegg dilemma: Legionnaires’ disease and retrograde contamination of dental unit waterlines. Infect Control Hosp Epidemiol 2016;37:1258e60. [5] Collins S, Walker J. Legionnaires’ disease from a dental unit. Chicken and egg or a different source entirely? J Hosp Infect 2017;96(2):203e4.
S. Petti* Department of Public Health and Infectious Diseases, Sapienza University, Rome, Italy * Corresponding author. Address: Sanarelli Building, Department of Public Health and Infectious Diseases, Sapienza University, Piazzale Aldo Moro 5, I-00185, Rome, Italy. Tel./fax: þ39 06 4991 4667. E-mail address: [email protected] Available online 13 April 2017 http://dx.doi.org/10.1016/j.jhin.2017.04.011 ª 2017 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.
Improvement in the management of patients with Clostridium difficile associated diarrhoea following changes to the wording of laboratory reports
Sir, Clinical manifestations of Clostridium difficile infection (CDI) range from asymptomatic colonization through mild diarrhoea to life-threatening pseudomembranous colitis. Management of patients with potential CDI is implemented based on clinical findings combined with laboratory testing. At Royal Berkshire NHS Foundation Trust (RBFT), diarrhoeal stool samples from hospital patients (Bristol stool chart type 5e7, not attributable to any underlying clinical condition or medication) above 2 years of age are tested for C. difficile [1,2].
205
From 2012 to 2015, initial screening using a glutamate dehydrogenase (GDH) immunoassay (EIA) test was performed at RBFT. If negative, a report was issued stating: ‘Clostridium difficile NOT detected. CDI is very unlikely.’ If the GDH EIA test was positive, a toxin EIA test was performed; if positive, a report was issued stating: ‘Toxin-producing Clostridium difficile DETECTED. CDI is likely to be present.’ Where the GDH EIA test was positive but the toxin EIA test was negative, a polymerase chain reaction (PCR) test was performed and the issued report stated: ‘Toxin-producing Clostridium difficile detected by PCR. Patient may have transmission potential. CDI could be present, please exercise clinical judgement.’ Anecdotally, healthcare workers (HCWs) at RBFT found the above report wording confusing. A two-part audit was performed to examine the effect of the wording of laboratory reports on the management of CDI. In April and May 2013 (Time Point 1), a questionnaire was circulated amongst HCWs on the wards. Participants were presented with the three possible laboratory reports generated as above, and asked whether the patient should be treated for CDI and whether they should be isolated; in each case, a simple ‘yes’ or ‘no’ answer was required. In addition, inpatients from April 2013 and March 2014 (Time Point 1) with GDH EIA- and PCR-positive results were identified and healthcare records were reviewed. Data were entered into a spreadsheet and analysed, and management was compared with accepted local guidelines. In 2015, the wording of laboratory reports was simplified. If the GDH EIA test was negative, the issued report stated: ‘Clostridium difficile NOT detected.’ If the GDH EIA and toxin EIA tests were positive, or the GDH EIA and PCR tests were positive, the issued report stated: ‘Toxin-producing Clostridium difficile DETECTED.’ Once this change was established, both parts of the audit were repeated between August and March 2015 (Time Point 2). At Time Points 1 and 2, there were 65 and 58 responses, respectively. The proportion of survey respondents giving the correct answer regarding management of C. difficile-positive and -negative patients before and after the change in report wording was compared using a two-tailed Chi-squared test (Table I). At Time Points 1 and 2, there were 52 and 57 patients eligible for inclusion, respectively, with sufficient information for analysis for 27 and 37 patients, respectively. At Time Point 2, 95% of patients required antibiotic treatment for CDI, compared with 52% at Time Point 1. At Time Points 1 and 2, treatment compliant with local guidelines was
Table I Comparison of percentage of correct survey responses before and after changes in report wording Clostridium difficile positive
Correct responses at Time Point 1 (%) Correct responses at Time Point 2 (%) Chi-squared test P-value
Clostridium difficile negative
Treat?
Isolate?
Treat?
Isolate?
86 86 0.00 0.99
93 100 4.65 0.03
86 98 6.03 0.01
83 84 0.04 0.83