Clinical and treatment-related risk factors for nosocomial colonisation with extensively drug-resistant Pseudomonas aeruginosa in a haematological patient population: a matched case control study

Abstract

BackgroundThis study aimed to investigate risk factors for colonisation with extensively drug-resistant P. aeruginosa (XDR-PA) in immunocompromised patients and to build a clinical risk score (CRS) based on these results.MethodsWe conducted a matched case–control study with 31 cases and 93 controls (1:3). Cases were colonised with XDR-PA during hospitalisation. Independent risk factors were determined using a three step conditional logistic regression procedure. A CRS was built with respect to the corresponding risk fraction of each risk factor, and its discriminatory power was estimated by receiver operating characteristic (ROC) analysis.ResultsThe presence of a central venous catheter (OR 7.41, P = 0.0008), the presence of a urinary catheter (OR 21.04, P < 0.0001), CRP > 10 mg/dl (OR 7.36, P = 0.0015), and ciprofloxacin administration (OR 5.53, P = 0.025) were independent risk factors. The CRS exhibited a high discriminatory power, defining a high risk population with an approximately fourteen times greater risk for XDR-PA colonisation.ConclusionsUnnecessary use of antibiotics, particularly ciprofloxacin should be avoided, and a high standard of infection control measures must be achieved when using medical devices. A CRS can be used for adaptation of the active screening culture policy to the local setting.Electronic supplementary materialThe online version of this article (doi:10.1186/s12879-014-0650-9) contains supplementary material, which is available to authorized users.

Prevalence and risk factors associated with colonization and infection of extensively drug-resistantPseudomonas aeruginosa: a systematic review

“…Exposure to antimicrobials, however, has been found to be an independent risk factor for XDR-PA acquisition in many studies, namely for fluoroquinolones [11,12,48,57,58], carbapenems [11], amikacin [48] or trimethoprim-sulfamethoxazole [48]. This leads to the conclusion that treatment with several antimicrobial classes predisposes for XDR-PA acquisition, but underlying reasons have not yet been clearly identified.…”

“…Thus, the association of device-related infection suggests itself for the case of XDR-PA, but has so far only been described in two studies. Central venous catheter and urinary catheter were both found to be independent risk factors in XDR-PA colonization [57], as was mechanical ventilation in a study analyzing XDR-PA infection and colonization [56].…”

“…However, the authors have not analyzed risk factors for colonization in the XDR-PA subgroup separately. Another recent study has focused on immunocompromised patients, with 31 cases of rectal or pharyngeal colonization with XDR-PA in a tertiary teaching hospital in Germany from 2010 to 2013 [57]. The consumption of ciprofloxacin as well as presence of a central venous catheter, presence of an urinary catheter and C-reactive protein during time at risk greater than 10 mg/dl have been identified as independent risk factors in the final conditional logistic regression model.…”

“…Moreover, there is an increased risk for XDR-PA acquisition in critically ill patients as defined by clinical risk scores such as Charlson index of ‡3 [11] or Acute Physiology and Chronic Health Evaluation II score [56]. Concomitant infection and inflammation further predispose patients, as both C-reactive protein >10 mg/dl [57] and presence of pneumonia [55] have been significantly associated with XDR-PA colonization and infection, respectively. Septic shock in patients during the early post-transplant period has been reported to be a risk factor for XDR-PA bacteremia, but the authors of this study have not excluded the possibility that XDR-PA sepsis might have been the underlying cause of septic shock in the first place [62].…”

“…The intestinal reservoir plays a crucial role in P. aeruginosa epidemiology and cultural approaches show that antibiotic pressure predisposes for rectal colonization with drug-resistant isolates [84]. In the future, next-generation sequencing techniques may be a promising approach to gain further insights into influences of antibiotics on resistance development Furthermore, clinical risk scores (CRS) could be generated based on the factors identified to be associated with risk for XDR-PA. CRS could provide clinicians with a practical tool directly applicable in patient care to identify patients at risk for colonization or infection with resistant strains [57,85]. CRS are considered most useful for stratification of screening strategies to be adopted for the requirements of individual hospitals.…”