Background: Improving good practice in antibiotics use is critical in challenging antimicrobial resistance. This study assessed knowledge and practices regarding antibiotic prescribing in children by physicians in both public and private health care in Goma, East of the Democratic Republic of Congo, a low-income country. Methods: A cross-sectional study using self -administered questionnaires was applied. Results: 147 physicians from twenty-five health care providers in the city of Goma participated in the study. More than three-quarters [85.7% (n=147] were General Practitioners from primary health care settings. More than two-thirds of the participants had over five years’ experience. In approximately three-quarters of cases [72.1%, (n=147)], the participants declared lack of recent training on antibiotic prescribing. In the five clinical situations posed to the participants, antibiotics prescribing practice was felt to be inappropriate or unnecessary in 15 to 80%. Antibiotic prescribing for symptoms of cough and fever, yellowish sputum, odynophagia, cold and flu and fever, positive “Thick smear” test and fever were categorized as unnecessary or inappropriate. An incorrect response concerning the susceptibility of Staphylococcus Methicillin-Resistant (MRSA) was demonstrated in more than three-quarters in General Practitioners [76.4%, (n=123)] compared to less than half in Specialists [41.2%, (n=123)] ( p =0.00). With regard to Enterococcus susceptibility, an incorrect response was noted in more than three-quarters in both General Practitioners and Specialists. A number of internal factors or determinants in health care institutions (Publics and Privates sectors) were noted to restrict good practice in antibiotics prescribing. Factors contributing to poor to practice in antibiotics prescribing were the uncertainty in the diagnosis, physicians who had only practiced in private hospitals and clinics and frequent antibiotics stock shortage in public or semi-public hospital. In more than a third of physicians, antibiotics resistance was not perceived as a problem in their daily practice or as a public health problem. Conclusions: Hospitals in Goma demonstrated inappropriate antibiotic prescribing practice. Strategies and policies such as Antimicrobial Stewardship and socio-anthropological approach need to be explored. Keywords: Knowledge, Practice, Antibiotic prescribing, Goma hospitals

Whether the risk of multidrug-resistant bacteria (MDRB) acquisition in the intensive care unit (ICU) is modified by the COVID-19 crisis is unknown. In this single center case control study, we measured the rate of MDRB acquisition in patients admitted in COVID-19 ICU and compared it with patients admitted in the same ICU for subarachnoid hemorrhage (controls) matched 1:1 on length of ICU stay and mechanical ventilation. All patients were systematically and repeatedly screened for MDRB carriage. We compared the rate of MDRB acquisition in COVID-19 patients and in control using a competing risk analysis. Of note, although we tried to match COVID-19 patients with septic shock patients, we were unable due to the longer stay of COVID-19 patients. Among 72 patients admitted to the COVID-19 ICUs, 33% acquired 31 MDRB during ICU stay. The incidence density of MDRB acquisition was 30/1000 patient days. Antimicrobial therapy and exposure time were associated with higher rate of MDRB acquisition. Among the 72 SAH patients, 21% acquired MDRB, with an incidence density was 18/1000 patient days. The septic patients had more comorbidities and a greater number of previous hospitalizations than the COVID-19 patients. The incidence density of MDRB acquisition was 30/1000 patient days. The association between COVID-19 and MDRB acquisition (compared to control) risk did not reach statistical significance in the multivariable competing risk analysis (sHR 1.71 (CI 95% 0.93–3.21)). Thus, we conclude that, despite strong physical isolation, acquisition rate of MDRB in ICU patients was at least similar during the COVID-19 first wave compared to previous period.

Increasing temperatures and rainfall variability in the Midwestern U.S. have spurred interest in strategies to reduce risks of heat and drought stress in traditionally rainfed crops including asparagus. A long-term field experiment was conducted on sandy soils in Western Michigan from 2010-17 to evaluate the effects of three levels of irrigation (none, overhead or sub-surface drip) and two asparagus cultivars (Guelph Millennium [GM] and Jersey Supreme [JS]) for reducing these risks. Overhead irrigation during the fern growth period resulted in cumulative yield improvements of 10% for GM during the 2012-17 growing seasons, with the largest yield benefits (21%) occurring in 2012, following hot, dry conditions the previous summer. In contrast, cumulative yields of JS were unaffected by irrigation, and yield reductions of 13% due to irrigation were observed in 2017, following wet conditions the previous late summer and fall. Estimates of cultivar water-use by depth suggest that JS was better able to tolerate drought due to a deeper root system compared to GM. However, our results suggest that JS may also be more sensitive than GM to excessive soil moisture during fall senescence. Yield response did not vary with delivery system, but sub-surface drip used less water than overhead irrigation. These results demonstrate the important role of both genetics and management practices in mitigating drought risk.

Introduction : Intestinal Clostridium difficile Infection (CDI) treated in hospitals may concern patients whose reason for admission is CDI (primary diagnosis) or who have acquired CDI during their stay (secondary diagnosis). Objectives : The objective of this study is to evaluate the cost for social security and hospitals and the length of hospital stays related to CDIs as the main reason for admission. Method : This study was carried out in 2012 in 13 Belgian hospitals. Cases were selected by using diagnosis recorded in minimum discharge summaries. Pediatric stays are not part of the inclusion criteria (n= 86). Results : The average length of stay (standard deviation) was 13.53 days (11.95). The average cost (standard deviation) covered by social security/hospitals was (sic)5,019.51 / (sic)6,286.39 (9,638.42/ 6,368.45). 7% of patients were admitted to the Intensive Care Unit during hospitalization, for an average duration (standard deviation) of 8.18 days (2.93). The mortality rate was 8.1%. 19.8% of patients used vancomycin during the stay, 43% were treated with metronidazole only, 12.8% used vancomycin and metronidazole and 24.4% do not received vancomycin or metronidazole. No patients received fidaxomycin. Conclusion : This study made it possible to approach the cost of CDI as the main reason for admission. Such data should allow contributing to optimally assess both the pharmacoeconmic impact of the implementation of prevention strategies and also therapeutic management making use of more expensive medicinal products but associated with decreased risk of recurrence.

Background The incidence of nosocomial infections due to carbapenem-resistant Klebsiella pneumoniae is increasing worldwide. Whole-genome sequencing (WGS) can help elucidate the transmission route of nosocomial pathogens. Methods We combined WGS and epidemiological data to analyze an outbreak of New Delhi metallo--lactamase (NDM)-producing K. pneumoniae that occurred in 2 Belgian hospitals situated about 50 miles apart. We characterized 74 NDM-producing K. pneumoniae isolates (9 from hospital A, 24 from hospital B, and 41 contemporary isolates from 15 other Belgian hospitals) using pulsed-field gel electrophoresis and WGS. Results A K. pneumoniae sequence type 716 clone was identified as being responsible for the outbreak with all 9 strains from hospital A and 20 of 24 from hospital B sharing a unique pulsotype and being clustered together at WGS (compared with 1 of 41 isolates from other Belgian hospitals). We identified the outpatient clinic of hospital B as the probable bridging site between the hospitals after combining epidemiological, phylogenetic, and resistome data. We also identified the patient who probably caused the transmission. In fact, all but 1 strain from hospital A carried a Tn1331-like transposon, whereas none of the hospital B isolates did. The patient from hospital A who did not have the Tn1331-like transposon was treated at the outpatient clinic of hospital B on the same day as the first NDM-producing K. pneumoniae-positive patient from hospital B. Conclusions The results from our WGS-guided investigation highlight the importance of implementing adequate infection control measures in outpatient settings, especially when healthcare delivery moves from acute care facilities to outpatient clinics. Combining whole-genome sequencing data with epidemiological data, we investigated an outbreak of New Delhi metallo--lactamase-producing Klebsiella pneumoniae across 2 Belgian hospitals. We identified the outpatient clinic as the likely common site of transfer between the 2 institutions.

INTRODUCTION:To estimate the prevalence "on any given day" of nosocomial infections and to determine their associated factors. Then, to estimate the prevalence of microorganisms responsible for nosocomial infections in Lubumbashi, Democratic Republic of Congo.METHODS:A descriptive cross-sectional study was conducted in two hospitals in Lubumbashi in five inpatient units (Surgery, Gynecology and Obstetrics, Internal Medicine, Pediatrics and Recovery). The sample consisted of 171 hospitalized patients who were questioned using a standardized questionnaire. Patient's medical record allowed us to know the type of antibiotic administered to the patient 48 hours after admission. Our study was conducted in February 2010 as part of the first local prevalence survey on nosocomial infections.RESULTS:Our study collected data on 59 patients with nosocomial infection. The overall prevalence was 34.5% (17.0% with acquired nosocomial infection and 17.5% with imported infection). According to the World Health Organization, nosocomial infection is a hospital-acquired infection which was not present or incubating at the time of patient admission. The following risk factors have been associated with acquired nosocomial infections: duration of hospitalization (long stay hospital patients, hospital length of stay of more than seven days has a higher risk than shorter length of stay, hospital length of stay of less than or equal to seven days (prevalence ratio: RP =3.6 [IC A 95%.1.4-8.9])). Among nosocomial infections, surgical site infections were the most common (27.1%), followed by lung infections (22.0%) and urinary tract infections (17.0%). Microbiological examination highlighted five germs responsible for nosocomial infection in infected patients: Escherichia coli (11.9%), Staphylococcus aureus (6.8%), Pseudomonas aeruginosa (5.1%), Shigella spp (5.1%) and Salmonella typhimurium (1.7%). Microbiological examination was performed in 31.0% (n = 59). Cefotaxime, third-generation cephalosporin was the most prescribed antibiotic (37.9%), followed by amoxicillin (19.6%) and ampicillin (16.3%) for monotherapy. Dual and triple therapy was also prescribed. Parenteral route was the most used for anti-infective administration. There was a significant difference in the prevalence of nosocomial infections between the two university hospitals; the prevalence of acquired nosocomial infection was 22.2% in University Clinics of Lubumbashi and 13.1% in Sendwe hospital.CONCLUSION:In our study, the overall prevalence of nosocomial infections was 34.5%. Surgical site infections were the most common (27,1%). Escherichia coli was the most common germ (11.9%).

We used a two-step whole genome sequencing analysis for resolving two concurrent outbreaks in two neonatal services in Belgium, caused by exfoliative toxin A-encoding-gene-positive (eta+) methicillin-susceptible Staphylococcus aureus with an otherwise sporadic spa-type t209 (ST-109). Outbreak A involved 19 neonates and one healthcare worker in a Brussels hospital from May 2011 to October 2013. After a first episode interrupted by decolonization procedures applied over 7 months, the outbreak resumed concomitantly with the onset of outbreak B in a hospital in Asse, comprising 11 neonates and one healthcare worker from mid-2012 to January 2013. Pan-genome multilocus sequence typing, defined on the basis of 42 core and accessory reference genomes, and single-nucleotide polymorphisms mapped on an outbreak-specific de novo assembly were used to compare 28 available outbreak isolates and 19 eta+/spa-type t209 isolates identified by routine or nationwide surveillance. Pan-genome multilocus sequence typing showed that the outbreaks were caused by independent clones not closely related to any of the surveillance isolates. Isolates from only ten cases with overlapping stays in outbreak A, including four pairs of twins, showed no or only a single nucleotide polymorphism variation, indicating limited sequential transmission. Detection of larger genomic variation, even from the start of the outbreak, pointed to sporadic seeding from a pre-existing exogenous source, which persisted throughout the whole course of outbreak A. Whole genome sequencing analysis can provide unique fine-tuned insights into transmission pathways of complex outbreaks even at their inception, which, with timely use, could valuably guide efforts for early source identification.

Background: Nasal and extra nasal carriage of methicillin-resistant S. aureus (MRSA) is a pre-existing condition that often leads to invasive MRSA infection, as MRSA colonization is associated with a high risk of acquiring MRSA infection during hospital stays. Decolonization may reduce the risk of meticillin-resistant Staphylococcus aureus (MRSA) infection in individual carriers and prevent transmission to other patients.Methods: A retrospective cohort study was conducted to evaluate the effectiveness of two decolonization protocols for newly diagnosed MRSA carriage in hospitalized patients and to assess the impact of decolonization on the rate of MRSA infection. The study population consisted of all patients diagnosed as MRSA-positive between January 2006 and June 2010.Patients diagnosed as carriers were designated as requiring contact precautions by the hospital infection control team. The standing order protocol of the hospital pertaining to decolonization procedures was then applied, and all newly diagnosed patients were administered one of the two decolonization treatments outlined in the hospital protocol, with the exception of MRSA respiratory carriers (MRSA obtained from sputum or other lower respiratory tract samples). The two decolonization treatments consisted of the application of intranasal mupirocin 2 % and washing with chlorhexidine soap (40 mg/mL) (mupi/CHX) or application of intranasal povidone-iodine and washing with povidone-iodine soap (PVPI), with each treatment lasting for 5 days.Success was determined by at least three successive nose swabs and throat and other screened site swabs that tested negative for MRSA before patient discharge.Results: A total of 1150 patients admitted to the hospital were found to be infected or colonized with MRSA. Of the 1150 patients, 268 were prescribed decolonization treatment. 104 out of 268 patients (39 %) were successfully decolonized. There was no significant success after two decolonization failures.MRSA infection rate among the successes and failures were 0.0 and 4.3 %, respectively [P = 0.04].Conclusions: Our results fit well with the prescription of decolonization based on local strategy protocols but reflect a low rate of successful treatment. Although the success rate of decolonization was not high in our study, the effectiveness of decolonization on the infection rate, justifies the continuation of this strategy, even if a marginal cost is incurred.

Background: Staphylococcus epidermidis is a pathogen that is frequently encountered in the hospital environment. Healthcare workers (HCWs) can serve as a reservoir for the transmission of S. epidermidis to patients.Methods: The aim of this study was to compare and identify differences between S. epidermidis isolated from 20 patients with catheter-related bloodstream infections (CRBSIs) and from the hands of 42 HCWs in the same hospital in terms of antimicrobial resistance, biofilm production, presence of the intercellular adhesion (ica) operon and genetic diversity (pulsed field gel electrophoresis (PFGE), multilocus sequence typing (MLST) and staphylococcal cassette chromosome (SCC) mec typing).Results: S. epidermidis isolates that caused CRBSI were resistant to significantly more non-betalactam drugs than were isolates collected from HCWs. Among the 43 mecA positive isolates (26 from HCWs), the most frequent SCCmec type was type IV (44%). The ica operon was significantly more prevalent in CRBSI isolates than in HCWs (P < 0.05). Weak in vitro biofilm production seemed to correlate with the absence of the ica operon regardless of the commensal or pathogenic origin of the isolate. The 62 isolates showed high diversity in their PFGE patterns divided into 37 different types: 19 harbored only by the CRBSI isolates and 6 shared by the clinical and HCW isolates. MLST revealed a total of ten different sequence types (ST). ST2 was limited to CRBSI-specific PFGE types while the "mixed" PFGE types were ST5, ST16, ST88 and ST153.Conclusion: One third of CRBSI episodes were due to isolates belonging to PFGE types that were also found on the hands of HCWs, suggesting that HCW serve as a reservoir for oxacillin resistance and transmission to patients. However, S. epidermidis ST2, mecA-positive and icaA-positive isolates, which caused the majority of clinically severe CRBSI, were not recovered from the HCW's hands.

Cluster randomised crossover trial with seven wards randomly allocated to intervention or control arm.Medical and surgical wards of a university hospital with active MRSA control programme.All patients hospitalized >48 h in study wards and screened for MRSA on admission and discharge Intervention: Rapid PCR-based screening test for MRSA compared with control screening test by enrichment culture using chromogenic agar.We determined the benefit of PCR-detection versus culture-based detection of MRSA colonisation upon patient admission on early implementation of isolation precautions and reduction of hospital transmission of MRSA.Cumulative rate of MRSA hospital acquisition of in patients screened negative on admission.The sequential order of inclusion of study wards in each arm was randomised by assigning a number to each ward and using a computer generated list of random numbers.Of 3704 eligible patients, 67.8% were evaluable for the study. Compared with culture, PCR-screening reduced the median test reporting time from admission from 88 to 11 hours (p<0.001) and the median time from admission to isolation from 96 to 25 hours (p<0.001). MRSA acquisition was detected in 36 patients (3.2%) in the control arm and 34 (3.2%) in the intervention arm. The incidence density rate of hospital acquired MRSA was 2.82 and 2.57/1,000 exposed patient-days in the control and intervention arm, respectively (risk ratio 0.91 (95% confidence interval, 0.60-1.39). Poisson regression model adjusted for colonisation pressure, compliance with hand hygiene and antibiotic use indicated a RR 0.99 (95% CI, 0.69 to 1.44).Universal PCR screening for MRSA on admission to medical and surgical wards in an endemic setting shortened the time to implement isolation precautions but did not reduce nosocomial acquisition of MRSA.clinicaltrials.gov NCT00846105.

Background: Catheter-related bloodstream infection (CRBSI) surveillance serves as a quality improvement measure that is often used to assess performance. We reviewed the total number of microbiological samples collected in three Belgian intensive care units (ICU) in 2009-2010, and we described variations in CRBSI rates based on two factors: microbiological documentation rate and CRBSI definition which includes clinical criterion for coagulase-negative Staphylococcus (CNS) episode.Findings: CRBSI rates were 2.95, 1.13 and 1.26 per 1,000 estimated catheter-days in ICUs A, B and C, respectively. ICU B cultured fewer microbiological samples and reported the lowest CRBSI rate. ICU C had the highest documentation rate but was assisted by support available from the laboratory for processing single CNS positive blood cultures. With the exclusion of clinical criterion, CRBSI rates would be reduced by 19%, 45% and 0% in ICUs A, B and C, respectively.Conclusion: CRBSI rates may be biased by differences of blood culture sampling and CRBSI definition. These observations suggest that comparisons of CRBSI rates in different ICUs remain difficult to interpret without knowledge of local practices.

BACKGROUND:We analyzed the impact associated with an intervention based on process control and performance feedback to decrease central line-associated bloodstream infection (CLABSI) rates.This study was conducted from March 2011 to September 2012 in five adult intensive care units (ICU) located in two Belgian tertiary hospitals A and B, with a total of 53 beds.METHODS:This study was divided in three phases: P1 (baseline), P2 (intervention) and P3 (post intervention).During P2, external monitoring of five central venous catheters (CVC) care critical processes and monthly reporting (meetings and feedbacks reports posted) of performance indicators (CLABSI rate, CVC utilization ratio, compliance rate with each care process, and insertion site) to ICU workers were performed. The external monitoring of process measures was assessed by the same trained research nurse.A Poisson regression analysis was used to compare CLABSI incidence density rate per phase. Statistical significance was achieved with 2-sided p-value of <0.05. For the analysis, we separated the five ICU in hospital A and B when appropriate.RESULTS:Significantly improved total mean compliance was achieved for hand hygiene, CVC handling and CVC dressing. CLABSI rate declined from 4.00 (95% confidence interval (CI): 1.94-6.06) to 1.81 (0.46-3.17) per 1,000 CVC-days in P2 with an incidence rate ratio (IRR) of 0.49 (0.24-0.98, p = 0.043). A better response was observed in hospital A where the nurse participation at the monthly meeting was significantly higher than in hospital B (p < 0.001) as the percentage of feedbacks reports posted in ICU (p < 0.001). The decline in the CLABSI rate observed during P2 in comparison with P1 was independent of the insertion site (femoral or non-femoral; p = 0.054). The overall CLABSI rate increased to 2.73 (1.17-4.29) per 1,000 CVC-days with IRR of 0.67 (0.36-1.26, p = 0.212) in P3 compared to P1, but a high nursing turnover was observed in both hospitals.CONCLUSIONS:Our intervention focused on external auditing and performance feedback resulted in significant reduction in rates of CLABSI. Investigation continues regarding the most effective way to sustain CLABSI prevention practices and to improve the culture of safety in healthcare.

Staphylococcus epidermidis is a major cause of catheter-related bloodstream infections (CRBSIs). Recent studies suggested the existence of well-adapted, highly resistant, hospital-associated S. epidermidis clones. The molecular epidemiology of S. epidermidis in Belgian hospitals and the Belgian community has not been explored yet. We compared a set of 33 S. epidermidis isolates causing CRBSI in hospitalized patients with a set of 33 commensal S. epidermidis isolates. The factors analyzed included resistance to antibiotics and genetic diversity as determined by pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), and SCCmec typing. Additionally, the presence of virulence-associated mobile genetic elements, the ica operon and the arginine catabolic mobile element (ACME), was assessed and compared against clinical data. CRBSI S. epidermidis isolates were significantly resistant to more antibiotics than commensal S. epidermidis isolates. The two populations studied were very diverse and genetically distinct as only 23% of the 37 PFGE types observed were harbored by both CRBSI and commensal isolates. ACME was found in 76% of S. epidermidis strains, regardless of their origin, while the ica operon was significantly more prevalent in CRBSI isolates than in commensal isolates (P<0.05). Nine patients presented a clinically severe CRBSI, eight cases of which were due to an ica-positive multiresistant isolate belonging to sequence type 2 (ST2) or ST54. S. epidermidis isolates causing CRBSI were more resistant and more often ica positive than commensal S. epidermidis isolates, which were genetically heterogeneous and susceptible to the majority of antibiotics tested. Clinically severe CRBSIs were due to isolates belonging to two closely related MLST types, ST2 and ST54.

Les virus grippaux alimentent l'actualité, en particulier depuis l'émergence d'un sous-type potentiellement pandémique, le virus A (H5N1). Il s'agit d'un virus aviaire, responsable d'une épizootie sans précédent à l'origine, jusqu'en mai 2009, de 423 cas d'infections humaines. Ce virus est responsable d'une pneumonie d'évolution rapide vers un syndrome de détresse respiratoire aiguë, entraînant la mort dans 60 % des cas. Le tableau de défaillance multiorganique décrit, semble être dû à une dysrégulation de la production de cytokines. L'infection par le virus A (H5N1) touche principalement l'enfant et l'adulte jeune. Pour l'expliquer, différentes hypothèses sont évoquées concernant la capacité de ces patients à réguler leur production de cytokines ainsi qu'une variation dans la répartition des récepteurs cellulaires. En fait, cette susceptibilité particulière de l'enfant semble être liée à des comportements à risque plus qu'à une réalité physiologique. Aujourd'hui, il est possible de prendre en charge efficacement un cas d'infection humaine par le virus A (H5N1) et les protocoles thérapeutiques d'utilisation des inhibiteurs de la neuraminidase ont été adaptés à l'enfant. Si à l'heure actuelle, le risque de survenue d'une pandémie grippale semble être associé au nouveau virus influenza A (H1N1), il est indispensable de continuer à surveiller activement la circulation du virus A (H5N1) ainsi que l'évolution génétique de ce virus hautement pathogène.The emerging A (H5N1) influenza virus is a clear pandemic threat. This avian virus is responsible for the largest epizootic event described so far. To date, 423 humans have been infected. In humans, this virus is responsible for a rapidly developing pneumonia, with an acute respiratory failure leading to death in 60 % of the infected cases. The multi-organ failure seems to result from the cytokine storm. A (H5N1) infections are mainly reported in children and young adults. Different hypotheses have been proposed to explain this specific feature, including the lack of control of cytokine release during infection, or the presence of alternative cellular receptors. The specific susceptibility of children is more likely to be related with exposure to infected birds than to specific immune or physiological factors. The proper and efficient management of A (H5N1) infection is possible nowadays. Today, the pandemic threat is real and may be imminent because of the circulation of new A (H1N1). However, an active surveillance of A (H5N1) virus remains very important to monitor the genetic evolution of this changing and virulent virus.

automated urine analyzer 3 M. Hallin,* A. Deplano, 1 S. Roisin, 1 V. Boyart, 1 R. De Ryck, 1 C. Nonhoff, 1 B. Byl, 2 Y. 4 Glupczynski 3 and O. Denis 5 1 Department of Microbiology, Erasme Hospital, Université Libre de Bruxelles, Brussels, 6 Belgium 7 Department of Infection Control, Erasme Hospital, Université Libre de Bruxelles, Brussels, 8 Belgium 9 3 National Reference Laboratory for Antibiotic resistance Monitoring in Gram-negative 10 bacteria, CHU Mont-Godinne, Universite Catholique de Louvain, Yvoir, Belgium 11 12 Running title: Pseudomonas aeruginosa pseudo-outbreak 13 14 *Corresponding author: 15 Marie Hallin, MD, PhD 16 Service de Microbiologie, Hôpital Erasme 17 808, route de Lennik, 1070 Brussels, Belgium 18 Phone: 32 2 555 34 84 Fax: 32 2 555 31 10 19 e-mail: mahallin@ulb.ac.be 20 21 22

By the end of May 2010, an increase in the number of urine specimens that were culture positive for extremely drug-resistant (XDR) Pseudomonas aeruginosa was observed in our 800-bed university hospital. This led to an infection control alert. No epidemiological link between the patients and no increase in the frequency of XDR P. aeruginosa in non-urine samples were observed. Therefore, a pseudo-outbreak due to analytical contamination in the laboratory was rapidly suspected. A prospective and retrospective search of cases was initiated, and the sampling of the automated urine analyzers used in the laboratory was performed. Antibiotypes were determined by disc diffusion, and genotypes were determined by pulsed-field gel electrophoresis (PFGE). From February to July 2010, 17 patients admitted to 12 different departments and 6 outpatients were included. The mixing device of the cytometric analyzer used for the numeration of urinary particles (Sysmex UF1000i) proved to be heavily contaminated. Isolates recovered from 12 patients belonged to the same antibiotype and PFGE type as the isolate recovered from the analyzer. Extensive disinfection with a broad-spectrum disinfectant and the replacement of the entire tubing was necessary to achieve the complete negativity of culture samples taken from the analyzer. A pseudo-outbreak caused by an XDR P. aeruginosa clone was proven to be due to the contamination of the cytometric analyzer for urinary sediment. Users of such analyzers should be aware that contamination can occur and should always perform culture either before the processing of the urine sample on the analyzer or on a distinct sample tube.