Letters to the Editor 353 4. Von Elm E, Altman DG, Egger M, Pocock SJ, Gøtzsche PC, Vandenbroucke JP. The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement: guidelines for reporting observational studies. Lancet 20 Oct 2007; 370(9596):1453e7. 5. Begg N, Cartwright KA, Cohen J, Kaczmarski EB, Innes JA, Leen CL, et al. Consensus statement on diagnosis, investigation, treatment and prevention of acute bacterial meningitis in immunocompetent adults. British Infection Society Working Party. J Infect juill 1999;39(1):1e15. 6. Tunkel AR, Hartman BJ, Kaplan SL, Kaufman BA, Roos KL, Scheld WM, et al. Practice guidelines for the management of bacterial meningitis. Clin Infect Dis 2004;39(9):1267e84. 7. 17th Consensus conference. Consensus conference on bacterial meningitis. Short text. Med Mal Infect mars 2009;39(3):175e86. 8. Auburtin M, Porcher R, Bruneel F, Scanvic A, Trouillet JL, Bedos JP, et al. Pneumococcal meningitis in the intensive care unit: prognostic factors of clinical outcome in a series of 80 cases. Am J Respir Crit Care Med 2002;165(5):713e7. 9. Bertrand S, Carion F, Wintjens R, Mathys V, Vanhoof R. Evolutionary changes in antimicrobial resistance of invasive Neisseria meningitidis isolates in Belgium from 2000 to 2010: increasing prevalence of penicillin nonsusceptibility. Antimicrobial Agents Chemother mai 2012;56(5):2268e72. 10. Weisfelt M, van de Beek D, Spanjaard L, Reitsma JB, de Gans J. Clinical features, complications, and outcome in adults with pneumococcal meningitis: a prospective case series. Lancet Neurol 2006;5(2):123e9. Lisanne Denneman APHP, Ho^pital Bichat, Service de reanimation medicale et infectieuse, F-75018 Paris, France Amandine Vial-Dupuy APHP, Ho^pital Bichat, Departement d’Epidemiologie et Recherche Clinique, F-75018 Paris, France Nathalie Gault APHP, Ho^pital Bichat, Departement d’Epidemiologie et Recherche Clinique, F-75018 Paris, France University Paris Diderot, Sorbonne Paris Cite, F-75018 Paris, France INSERM, U738, F-75018 Paris, France Michel Wolff APHP, Ho^pital Bichat, Service de reanimation medicale et infectieuse, F-75018 Paris, France University Paris Diderot, Sorbonne Paris Cite, F-75018 Paris, France Diederik van de Beek Academic Medical Center, Department of Neurology, Center for Infection and Immunity Amsterdam (CINIMA), Amsterdam, The Netherlands Bruno Mourvillier* APHP, Ho^pital Bichat, Service de reanimation medicale et infectieuse, F-75018 Paris, France ^pital Bichat, Service de *Corresponding author. Ho animation me dicale et infectieuse, 46 rue Henri Huchard, re 75018 Paris, France. Tel.: þ33 1 40257703; fax: þ33 1 40258837. E-mail address: bruno.mourvillier@bch.aphp.fr Accepted 1 May 2013 ª 2013 The British Infection Association. Published by Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.jinf.2013.05.001 Assessing microbial colonization of peripheral intravascular devices Dear Editor, We read with interest the recent paper by Molina J et al., which discussed mortality and hospital stay related to coagulase-negative staphylococci bacteraemia caused by intravascular devices (IVD) in non-critical patients.1 The most frequently isolated bacteria on IVD are coagulasenegative staphylococcus,2 it is, therefore, critical for researcher to assess IVD related infections and develop efficient strategies to prevent IVD-related infections. Peripheral intravascular devices (PIVDs) are one of the most frequently used medical invasive devices in hospitals3 and it is estimated that 200 million PIVDs are used annually in the USA.4 PIVD-related infections occur at lower incidence than many other IVD types, but constitute serious and potentially life-threatening infections, exacerbated by the high frequency of use.5 To reduce the incidence of PIVD-related infections, many strategies have been applied including hand hygiene, aseptic technique during PIVD insertion and skin preparation.6 In many hospitals, peripheral catheters are inserted by medical staffs with limited experience in IV catheter care. Several studies have suggested that a dedicated IV therapy team may reduce catheter-related complications.7 In addition, routine replacement of catheters was believed to be the critical factor in reducing the occurrence of complications. Furthermore, an intervention to reduce PIVD-related infection used in recent years has been to artificially shorten the dwell time of individual devices.2 We conducted a randomized, prospective, controlled trial to assess how time in situ contributes to PIVD colonization; to assess the effectiveness of routine Day 3 removal of PIVDs in preventing microbial colonization; and to assess whether the use of IV team decreases PIVD complication. After ethics committee approval, and patients’ informed consent, the study was conducted at three teaching hospitals in Queensland, Australia. PIVDs were inserted and cared for in accordance with usual hospital practice except for the approach to catheter removal which was randomized to either removal on clinical indication (clinical change group: CC), or routinely every three days (routine change group: RC). Randomization was a 1:1 ratio, computer generated after patient consent, and concealed until this time. Clinical staffs were then aware of allocation but the endpoint raters for colonization were blinded. IV teams inserted 40% of devices, with the remainder-inserted by general medical and nursing staff. PIVDs were Insyte Autoguard (BD Medical, 354 Table 1 Letters to the Editor Peripheral intravascular device (PIVD) colonization according to patient and intervention characteristics. Variable Study group Clinical change group Routine change group Time in situ, median (quartiles) Gender Male Female Age (years) (mean  SD) Inserter type IV service Other clinician Insertion site Ward Emergency Operating theatre/Radiology Hospital 1 2 3 IV antibiotics Yes No IV medications Yes No 14 Colonized PIVD 284 Uncolonized PIVD Risk ratio or mean difference 95% CI P 8 6 118.5 (73, 173) 135 149 72.5 (55, 98) 1.44 (0.51e4.06) 0.59 44.5 (13.9e75.2) 0.004 10 4 51.0  19.4 191 103 55.8  18.3 1.33 (0.43e4.14) 0.78 4.8 (7.9e17.5) 0.46 3 11 139 145 0.30 (0.09e1.05) 0.06 10 0 4 222 27 35 N/A 0.13 3 7 4 96 100 88 N/A 0.52 12 2 209 75 2.09 (0.48e9.13) 0.53 5 9 126 158 0.71 (0.24e2.06) 0.59 IV - intravenous. Franklin Lakes, USA). Dressings (transparent semipermeable) were used for 7 days, or changed earlier if loose or soiled. A 5% convenience sample was taken. When the PIVD was no longer required, the nurse removed the PIVD and distal 2 cm of the tip was cut. All PIVD tips were handled under aseptic conditions and immediately transported to laboratory and cultured by the semi-quantitative method.8 Baseline characteristics of patients and devices, all of which are described as frequencies (%) except for age (mean and SD), were compared using a two-sided Fisher’s exact test. Relative incidence rates (RR) of PIVDrelated colonization per 100 devices/patients and also aggregated incidence rate ratio comparisons (IRRs) per 1000 device days, both with 95% confidence intervals, were calculated to compare colonization rates. Median dwell times were compared using the ManneWhitney test. Multivariate (Cox regression) modelling assessed possible associations between age, gender, number of comorbidities, study group, hospital, inserter type, insertion site, IV antibiotics or other IV medications with colonization rates. Statistical analysis was completed using StataSE (Version 10, College Station, TX). P values of <0.05 were considered statistically significant. A total of 298 PIVDs were studied in 260 patients. The median patient age was 56 years and 64% were male. One hundred and forty six (55%) patients had multiple comorbidities. Of the 260 patients, 127 were randomised to receive routine PIVD change (RC group) and 133 patients were randomised to the clinical change group (CC group). Eight of 143 (6.3%) (CC) vs 6 of 155 (4.5%) (RC) PIVDs were colonized, and this was not statistically different between groups (see Table 1). The most frequently identified organism was coagulase-negative staphylococcus. Others included staphylococcus, bacillus, candida, corynebacterium and streptococcus species. Median PIVD time in situ was significantly longer in colonized than uncolonized PIVDs, but this was not significant when viewed by study group as rates per 1000 PIVD days (CC 14.6/1000 PIVD Days vs RC 14.4/1000 PIVD Days, IRR 1.02, 95% CI 0.34e3.21, p Z 0.98, Table 1). Multivariate (timeadjusted per 1000 PIVD days) modelling found no significant variables (including study group) associated with colonization. The application of IV team might decrease PIVD-related infections but the difference was not statistically significant (p Z 0.06). No statistically significant differences were seen regarding the other evaluation criteria on PIVD colonization: gender, age, insertion site, hospital, antibiotic treatment and intravascular medications. The results suggest that increased dwell time is significantly associated with colonization, and this is not prevented by routinely removing devices. Over the course of a treatment period, the rates of colonization are not significantly different when PIVDs are left in situ as long as Letters to the Editor clinically needed and they remain functional, compared to removal every 3e4 days. The observed colonization rate was 4.7% at a threshold of 15 cfu. Few studies have been published that deal specifically with PIVD colonization. One French study of pre-hospital inserted PIVDs found a similar rate of 4.1% colonization, despite patient and analytic differences.9 Our devices would not usually have been cultured in clinical practice and clinicians would assume that they were sterile, when our findings show that this is not the case. Insertion by an IV team appeared somewhat protective of colonization although was not remain predictive on the multivariate analysis. The most frequently isolated microbes in this study were coagulasenegative staphylococci, and this is consistent with the findings of colonization in many IVD types.2 However, it has been shown that culture methods although commonly used, are of limited value for slow-growing or fastidious bacteria or intracellular pathogens.10 The sensitivity of the semi-quantitative method might also be reduced if the patient is receiving antibiotic treatment.10 Therefore, many pathogenic bacteria might not have been isolated in this study because of the techniques used, and the true bacterial colonization rate may be higher than shown here. Funding C.M.R. received grant support from Australian National Health and Medical Research Council. L.Z. is supported by Australian National Health and Medical Research Council Training-Clinical Research Fellowship (grant number 597491). Potential conflicts of interest All authors report no conflict of interest relevant to this article. References 1. Molina J, Penuela I, Lepe JA, Gutierrez-Pizarraya A, Gomez MJ, Garcia-Cabrera E, et al. Mortality and hospital stay related to coagulase-negative Staphylococci bacteremia in non-critical patients. J of Infect 2013;66(2):155e62. 2. Mermel LA, Allon M, Bouza E, Craven DE, Flynn P, O’Grady NP, et al. Clinical practice guidelines for the diagnosis and management of intravascular catheter-related infection: 2009 update by the infectious diseases society of America. Clin Infect Dis 2009;49(1):1e45. 3. Zingg W, Pittet D. Peripheral venous catheters: an under-evaluated problem. International Journal of Antimicrobial Agents 2009;34(Suppl. 4):S38e42. 4. Maki DG. Improving the safety of peripheral intravenous catheters. BMJ 2008;337(7662). 5. Maki DG, Kluger DM, Crnich CJ. The risk of bloodstream infection in adults with different intravascular devices: a systematic review of 200 published prospective studies. Mayo Clinic Proc 2006;81(9):1159e71. 6. O’Grady NP, Alexander M, Burns LA, Dellinger EP, Garland J, Heard SO, et al. Guidelines for the prevention of intravascular catheter-related infections. Clin Infect Dis 2011;52(9):e162e93. 7. Soifer NE, Borzak S, Edlin BR, Weinstein RA. Prevention of peripheral venous catheter complications with an intravenous therapy team e a randomized controlled trial. Arch Intern Med 1998;158(5):473e7. 355 8. Maki DG, Weise CE, Sarafin HW. A semiquantitative culture method for identifying intravenous catheter-related infections. N Engl J Med 1977;296:1305e9. 9. Ezingeard E, Coudrot M, Guyomarc’h S, Aubert G, Blanc JL, Bertrand JC, et al. Evaluation of colonisation of peripheral venous catheters inserted by prehospital emergency service teams (SMUR) in France. J Hosp Infect 2009;72(2):169e75. 10. Mancini N, Carletti S, Ghidoli N, Cichero P, Burioni R, Clementi M. The era of molecular and other non-culture-based methods in diagnosis of sepsis. Clin Microbiol Rev 2010;23(1):235. Li Zhang* Griffith Health Institute-Health Practice Innovation, Griffith University, N48 Nathan Campus, 170 Kessels Road, Nathan, Queensland 4111, Australia *Corresponding author. Tel.: þ61 7 37357272; fax: þ61 7 3735 3560. Nicole Marsh Griffith Health Institute-Health Practice Innovation, Griffith University, N48 Nathan Campus, Nathan, Queensland 4111, Australia Research Development Unit, Centre for Clinical Nursing, Royal Brisbane and Women’s Hospital, Herston, Queensland, Australia Matthew R. McGrail School of Rural Health, Monash University, Gippsland, Victoria, Australia Joan Webster Griffith Health Institute-Health Practice Innovation, Griffith University, N48 Nathan Campus, Nathan, Queensland 4111, Australia Research Development Unit, Centre for Clinical Nursing, Royal Brisbane and Women’s Hospital, Herston, Queensland, Australia Elliott G. Playford Infection Management Services, Princess Alexandra Hospital, Woolloongabba, Queensland, Australia Claire M. Rickard Griffith Health Institute-Health Practice Innovation, Griffith University, N48 Nathan Campus, Nathan, Queensland 4111, Australia Research Development Unit, Centre for Clinical Nursing, Royal Brisbane and Women’s Hospital, Herston, Queensland, Australia Infection Management Services, Princess Alexandra Hospital, Woolloongabba, Queensland, Australia E-mail address: li.zhang@griffith.edu.au Accepted 5 June 2013 ª 2013 The British Infection Association. Published by Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.jinf.2013.06.001