Accepted Manuscript Is it time to move from standard to targeted surgical prophylaxis? Dr A. Quirino, C. Torti, G. Cortese, P. Morelli, M.C. Reale, P. Mastroroberto, G. Matera, M.C. Liberto, A. Focà PII:
S0195-6701(16)30320-6
DOI:
10.1016/j.jhin.2016.07.020
Reference:
YJHIN 4885
To appear in:
Journal of Hospital Infection
Received Date: 15 July 2016 Accepted Date: 29 July 2016
Please cite this article as: Quirino A, Torti C, Cortese G, Morelli P, Reale MC, Mastroroberto P, Matera G, Liberto MC, Focà A, Is it time to move from standard to targeted surgical prophylaxis?, Journal of Hospital Infection (2016), doi: 10.1016/j.jhin.2016.07.020. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
ACCEPTED MANUSCRIPT Is it time to move from standard to targeted surgical prophylaxis?
Quirino A.1*, Torti C.2*, Cortese G. 1, Morelli P. 1, Reale M.C. 1, Mastroroberto P.3, Matera G.1,
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Liberto M.C.1, Focà A.1
1
Unit of Clinical Microbiology, Department of Health Sciences, “Magna Graecia” University of Catanzaro, Catanzaro, Italy.
2
Unit of Infectious Diseases, Department of Medical and Surgical Sciences, “Magna Graecia” University of Catanzaro, Catanzaro, Italy.
3
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Unit of Cardiac Surgery, Department of Medical and Surgical Sciences, “Magna Graecia” University of Catanzaro, Catanzaro, Italy.
*These two authors have contributed equally to the work
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Corresponding author Dr Angela Quirino
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University “Magna Graecia” of Catanzaro Viale Europa, 88100 Catanzaro
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Phone: +3909613697748 e-mail:
[email protected]
ACCEPTED MANUSCRIPT Sir, Current guidelines for surgical prophylaxis recommend the use of specific antibiotics based on type of intervention and risk of infection due to commensal bacteria in proximity to the surgical site (either skin or body cavities).1 However, increasing numbers of patients are colonized by multidrug-resistant (MDR) bacteria, which may limit effectiveness of the standard regimens used for prophylaxis. At the same time, widespread use of very broad-spectrum drugs as prophylaxis in case patients may carry MDR bacteria should
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be considered inappropriate as it may promote emergence and transmission of further MDR isolates. Our question therefore was whether routine pre-operative screening (nasal, throat and rectal swabs) can provide useful information to select the most appropriate drugs for prophylaxis.
From June 2015 to April 2016, all inpatients at the Cardiac Surgery Unit were screened on admission
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by obtaining nasal, throat and rectal swabs. Nasal swabs were screened for Staphylococcus aureus only, by culture on salt mannitol plates. Throat and rectal swabs were cultured on blood and MacConkey agar plates;
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Escherichia coli was considered to be a typical commensal species of the rectum and isolates from the site were excluded, but all other Enterobacteriaceae from any site were investigated and recorded. All cultures were maintained for 48 hours; isolates of interest were identified, and antibiotic susceptibilities determined, using the Vitek-2 system (bioMérieux, France).
A total of 209 patients were screened. Only one patient did not receive a rectal swab. Overall, 9%, 15.3% and 6.7% of nasal, throat and rectal swabs, respectively, yielded one or more bacterial isolates of
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interest. The majority (19%) of patients tested positive only at one site; 5% had bacteria of interest at two sites, and 1% at all three sites. Among the 69 isolated strains, the most frequent species were: Klebsiella pneumoniae (29%), followed by S. aureus (27%), Escherichia coli (10%), Pseudomonas aeruginosa (9%), K. oxytoca (6%), Enterobacter cloacae (4%), and Serratia marcescens (3%). Acinetobacter baumannii,
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Stenotrophomonas. maltophilia, Pantoea spp., Proteus mirabilis, Citrobacter freundii, E. aerogenes, Raoultella planticola and Aeremonas spp. contributed 1% each. For K. pnemoniae 68% of isolates were
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obtained from rectal swabs (the remaining from throat), while 83% P. aeruginosa were obtained from throat swabs (the remaining isolate from a rectal swab). All the remaining Enterobacteria were isolated from throat swabs. This is important because the main risk of infection at the surgical (sternal) site could be attributed to bacteria present in throat and nose sites.2 We isolated a wide range of species from throat swabs. However, resistance to the drugs used for standard prophylaxis (i.e., first or second generation cephalosporins) was uncommon, being present in 6/6 P. aeruginosa, 1/1 A. baumannii, 1/2 S. marcescens, and 1/7 E. coli. Not only was the overall prevalence of antibiotic resistance amongst bacteria of interest relatively low, but the proportion of patients colonised with any bacteria of interest was low. Thus, only 4.3% of patients undergoing cardiac surgery were colonised preoperatively with Gram-negative bacteria that were resistant to standard peri-operative prophylactic antibiotics. Routine screening would appear to have only marginal benefit in tailoring antibiotic prophylaxis in our patient population. Perhaps unexpectedly, S. aureus was isolated from a substantial proportion of
ACCEPTED MANUSCRIPT patients, which may be seen as supporting the routine use of decolonisation treatment with chlorexidine and mupirocin.3,4 3/19 S. aureus were methicillin-resistant (MRSA), giving an overall MRSA in our patients of only 1.4%. In conclusion, whilst a surprisingly high proportion of patients were throat carriers of Gram-negative bacteria, the great majority of these were susceptible to the first- and second-generation cephalosporins that
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are routinely used as peri-operative antibiotic prophylaxis in our centre. Therefore, we believe that routine pre-operative swabbing is not supported by our data. However, some notes of caution should be emphasized. First, rectal swabbing was performed in uncontrolled conditions, so we cannot be sure that true rectal swabs (obtained in such a way to ensure that there was a faecal material on the swab) were always collected. Second, MRSA screening was performed on nasal swabs only,3 and enrichment culture methods were not
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used; thus the true prevalence of MRSA may be underestimated. We also do not know whether patients colonized by these bacteria are at risk of post-operative infections despite appropriate prophylaxis, especially
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if the bacterial load is significant; more studies are needed in this respect. Finally, identification of patients who are asymptomatically colonized with multidrug-resistant bacteria allows institution of infection prevention and control measures that can protect other patients from acquiring these bacteria. Thus, whilst our data are at first glance reassuring, further work is required to quantify more precisely the possible benefits to the individual patient, and the wider hospital population, of pre-operative screening for multidrug-
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resistant bacteria.
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References
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1. Bratzler DW, Dellinger EP, Olsen KM, et al. Clinical practice guidelines for antimicrobial prophylaxis in surgery. Am J Health-Syst Pharm 2013;70:195-283.
2. Lytsy B, Lindblom RP, Ransjö U, Leo-Swenne C. Hygienic interventions to decrease deep sternal wound infections following coronary artery bypass grafting. J Hosp Infect 2015;91:326331.
infection N Engl J Med 2013;368:2255-2226.
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3. Huang SS, Septimus E, Kleinman K, et al. Targeted versus universal decolonization to prevent ICU
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4. Bode LG, Kluytmans JA, Wertheim HF, et al. Preventing surgical-site infections in nasal carriers of
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Staphylococcus aureus. N Engl J Med 2010;362:9-17.
