- Email: [email protected]
Response to ‘Re: Carbapenemase screening – the role of routinely screening urine samples?’
Journal of Hospital Infection 95 (2017) 69e70 Available online at www.sciencedirect.com
Journal of Hospital Infection journal homepage: www.elsevierhealth.com/journals/jhin
Letter to the Editor
Response to ‘Re: Carbapenemase screening e the role of routinely screening urine samples?’
Sir, We read with interest the recent editorial by Wilson and agree with Collins et al. that the laboratory can act as a ‘safety net’ for carbapenemase-producing Enterobacteriaceae (CPE) detection.1,2 Following the publication of Public Health England laboratory (PHE) guidelines recommending that ‘all clinically significant isolates of Enterobacteriaceae should be tested against a carbapenem’, the Nottingham University Hospitals Microbiology laboratory recognized that urine samples account for the vast majority of Enterobacteriaceae isolates, and that these were not being routinely tested against a carbapenem.3 In Nottingham, urine testing is performed using the Mast Uri System, a semi-automated system consisting of inoculation and reading of pre-poured microtitre plates with media for bacterial identification and sensitivity testing. In addition to the antibiotics for clinical use, an ertapenem plate with a concentration of 1 mg/L was added to the system as a screening carbapenem test. Although meropenem has previously been recommended as a suitable screening carbapenem, ertapenem was chosen for its higher sensitivity to CPE isolates; with the acknowledgement that some non-carbapenemaseproducing Enterobacteriaceae (such as Enterobacter species) would test resistant and require further laboratory work to accurately interpret the ertapenem result.4 Since the introduction of ertapenem screening of urine isolates, we have identified two cases of CPE colonization that may have otherwise remained unknown and could have potentially acted as reservoirs for transmission. The first case was an adult male, with a urine sample collected by the general practitioner. Citrobacter freundii was isolated; testing sensitive to trimethoprim and nitrofurantoin, and resistant to ertapenem. This was subsequently confirmed as a New Delhi Metallo-beta-lactamase (NDM)-positive strain by the Antibiotic Resistance Monitoring and Reference Laboratory (ARMRL), Public Health England, Colindale, UK. On further enquiry, the patient had an epidemiological risk factor of having had surgery in the Philippines, requiring a urinary catheter. The second case was an adult female, with a urine sample collected by the general practitioner. Escherichia coli was isolated; testing sensitive to nitrofurantoin and mecillinam,
and resistant to ertapenem. This was subsequently confirmed by the ARMRL as an OXA-48-positive strain. The only identifiable risk factor was a holiday in Turkey the previous year; this would not have met the criteria for admission CPE screening based on current guidance.5 Most significantly these strains remained sensitive to some first-line antibiotics, and, without the ertapenem plate, would not have been alerted for further sensitivity testing. Interestingly the OXA-48 strain tested sensitive to mecillinam (plate concentration of 16 mg/L); mecillinam sensitivity has been previously described for a proportion of OXA-48 strains.6 The detection of CPE triggered an early clinical and infection prevention and control response while these patients remained in the community. In addition, prior knowledge of colonization with CPE isolates also highlighted the requirement to implement infection control precautions, if these patients were admitted using the hospital patient administration system. Despite the recommendation to test all clinically significant Enterobacteriaceae for carbapenem sensitivity, PHE data suggest variation in practice with a minority of areas not routinely testing E. coli blood isolates for carbapenem sensitivity.7 As Collins et al. highlight, although urine samples are not as sensitive as rectal swabs or stool for the detection of CPE carriage, they are the most widely collected microbiological sample in both community and inpatient settings. We provide further evidence that screening all urine samples for CPE not only enhances the clinical and infection control response to this threat, but provides vital information on the distribution of these organisms in the community. The consequences of failure to detect and control the spread of these multi-resistant organisms are far-reaching; based on our experience, we recommend routine testing in all laboratories for carbapenem resistance in urine coliform isolates. Conflict of interest statement None declared. Funding sources None.
References 1. Wilson APR. Screening for carbapenem-resistant organisms. J Hosp Infect 2016;94:116e117. 2. Collins M, Holland D, Weinbren M. Re: Carbapenemase screening e the role of routinely screening urine samples? J Hosp Infect 2016;94:405. 3. Standards Unit, Microbiology Investigation Services, Public Health England. Laboratory detection and reporting of bacteria with
http://dx.doi.org/10.1016/j.jhin.2016.10.015 0195-6701/ª 2016 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.
70
4.
5.
6.
7.
Letter to the Editor / Journal of Hospital Infection 95 (2017) 69e70 carbapenem-hydrolysing b-lactamases (carbapenemases). London: PHE; 2016. Giske CG, Martinez-Martinez L, Canto ´n R, et al. EUCAST guideline for the detection of resistance mechanisms and specific resistances of clinical and/or epidemiological importance. Version 1.0. European Committee on Antimicrobial Susceptibility Testing; 2013. Public Health England. Acute trust toolkit for the early detection, management and control of carbapenemase-producing Enterobacteriaceae. London: PHE; 2013. Marrs ECL, Day KM, Perry JD. In vitro activity of mecillinam against Enterobacteriaceae with NDM-1 carbapenemase. J Antimicrob Chemother 2014;69:2873e2875. Public Health England. Public Health Profiles: AMR Local Indicators. Percentage of E. coli blood specimens (from English laboratories) with susceptibility tests to a carbapenem; by CCG and by Quarter. Available at: http://fingertips.phe.org.uk/profile/ amr-local-indicators [last accessed October 2016].
A. Joseph* G. White V. Weston Department of Clinical Microbiology, Nottingham University Hospitals NHS Trust, Nottingham, UK * Corresponding author. Address: Department of Clinical Microbiology, Nottingham University Hospitals NHS Trust, QMC Campus, Derby Road, Nottingham NG7 2UH, UK. Tel.: þ44 (0) 115 9709163; fax: þ44 (0)115 9709767. E-mail address: [email protected] (A. Joseph). Available online 27 October 2016
Journal of Hospital Infection journal homepage: www.elsevierhealth.com/journals/jhin
Letter to the Editor
Response to ‘Re: Carbapenemase screening e the role of routinely screening urine samples?’
Sir, We read with interest the recent editorial by Wilson and agree with Collins et al. that the laboratory can act as a ‘safety net’ for carbapenemase-producing Enterobacteriaceae (CPE) detection.1,2 Following the publication of Public Health England laboratory (PHE) guidelines recommending that ‘all clinically significant isolates of Enterobacteriaceae should be tested against a carbapenem’, the Nottingham University Hospitals Microbiology laboratory recognized that urine samples account for the vast majority of Enterobacteriaceae isolates, and that these were not being routinely tested against a carbapenem.3 In Nottingham, urine testing is performed using the Mast Uri System, a semi-automated system consisting of inoculation and reading of pre-poured microtitre plates with media for bacterial identification and sensitivity testing. In addition to the antibiotics for clinical use, an ertapenem plate with a concentration of 1 mg/L was added to the system as a screening carbapenem test. Although meropenem has previously been recommended as a suitable screening carbapenem, ertapenem was chosen for its higher sensitivity to CPE isolates; with the acknowledgement that some non-carbapenemaseproducing Enterobacteriaceae (such as Enterobacter species) would test resistant and require further laboratory work to accurately interpret the ertapenem result.4 Since the introduction of ertapenem screening of urine isolates, we have identified two cases of CPE colonization that may have otherwise remained unknown and could have potentially acted as reservoirs for transmission. The first case was an adult male, with a urine sample collected by the general practitioner. Citrobacter freundii was isolated; testing sensitive to trimethoprim and nitrofurantoin, and resistant to ertapenem. This was subsequently confirmed as a New Delhi Metallo-beta-lactamase (NDM)-positive strain by the Antibiotic Resistance Monitoring and Reference Laboratory (ARMRL), Public Health England, Colindale, UK. On further enquiry, the patient had an epidemiological risk factor of having had surgery in the Philippines, requiring a urinary catheter. The second case was an adult female, with a urine sample collected by the general practitioner. Escherichia coli was isolated; testing sensitive to nitrofurantoin and mecillinam,
and resistant to ertapenem. This was subsequently confirmed by the ARMRL as an OXA-48-positive strain. The only identifiable risk factor was a holiday in Turkey the previous year; this would not have met the criteria for admission CPE screening based on current guidance.5 Most significantly these strains remained sensitive to some first-line antibiotics, and, without the ertapenem plate, would not have been alerted for further sensitivity testing. Interestingly the OXA-48 strain tested sensitive to mecillinam (plate concentration of 16 mg/L); mecillinam sensitivity has been previously described for a proportion of OXA-48 strains.6 The detection of CPE triggered an early clinical and infection prevention and control response while these patients remained in the community. In addition, prior knowledge of colonization with CPE isolates also highlighted the requirement to implement infection control precautions, if these patients were admitted using the hospital patient administration system. Despite the recommendation to test all clinically significant Enterobacteriaceae for carbapenem sensitivity, PHE data suggest variation in practice with a minority of areas not routinely testing E. coli blood isolates for carbapenem sensitivity.7 As Collins et al. highlight, although urine samples are not as sensitive as rectal swabs or stool for the detection of CPE carriage, they are the most widely collected microbiological sample in both community and inpatient settings. We provide further evidence that screening all urine samples for CPE not only enhances the clinical and infection control response to this threat, but provides vital information on the distribution of these organisms in the community. The consequences of failure to detect and control the spread of these multi-resistant organisms are far-reaching; based on our experience, we recommend routine testing in all laboratories for carbapenem resistance in urine coliform isolates. Conflict of interest statement None declared. Funding sources None.
References 1. Wilson APR. Screening for carbapenem-resistant organisms. J Hosp Infect 2016;94:116e117. 2. Collins M, Holland D, Weinbren M. Re: Carbapenemase screening e the role of routinely screening urine samples? J Hosp Infect 2016;94:405. 3. Standards Unit, Microbiology Investigation Services, Public Health England. Laboratory detection and reporting of bacteria with
http://dx.doi.org/10.1016/j.jhin.2016.10.015 0195-6701/ª 2016 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.
70
4.
5.
6.
7.
Letter to the Editor / Journal of Hospital Infection 95 (2017) 69e70 carbapenem-hydrolysing b-lactamases (carbapenemases). London: PHE; 2016. Giske CG, Martinez-Martinez L, Canto ´n R, et al. EUCAST guideline for the detection of resistance mechanisms and specific resistances of clinical and/or epidemiological importance. Version 1.0. European Committee on Antimicrobial Susceptibility Testing; 2013. Public Health England. Acute trust toolkit for the early detection, management and control of carbapenemase-producing Enterobacteriaceae. London: PHE; 2013. Marrs ECL, Day KM, Perry JD. In vitro activity of mecillinam against Enterobacteriaceae with NDM-1 carbapenemase. J Antimicrob Chemother 2014;69:2873e2875. Public Health England. Public Health Profiles: AMR Local Indicators. Percentage of E. coli blood specimens (from English laboratories) with susceptibility tests to a carbapenem; by CCG and by Quarter. Available at: http://fingertips.phe.org.uk/profile/ amr-local-indicators [last accessed October 2016].
A. Joseph* G. White V. Weston Department of Clinical Microbiology, Nottingham University Hospitals NHS Trust, Nottingham, UK * Corresponding author. Address: Department of Clinical Microbiology, Nottingham University Hospitals NHS Trust, QMC Campus, Derby Road, Nottingham NG7 2UH, UK. Tel.: þ44 (0) 115 9709163; fax: þ44 (0)115 9709767. E-mail address: [email protected] (A. Joseph). Available online 27 October 2016