[URISCAM project: Multicenter evaluation of the UF-Series cytometer in the urinary tract infections screening]

OBJECTIVE

Urine culture, the gold standard to confirm the presence of urinary tract infection (UTI), is the most requested assay in the microbiology department. Our objective was to determine the diagnostic yield of the UF-Series cytometer as a screening method for UTI.

METHODS

All the urine samples sent to the six Microbiology Laboratories participating in a period of 5 working days were analyzed. We collected demographic variables, apart from those variables related to urine samples: source and sample type (midstream, catheterized or nephrostomy urines), collection with/without boric acid, cytometer parameters (leukocyturia, bacteriuria, bacteria morphology and epithelial cells) and urine culture results. ROC curves were plotted to determine predictive capacity of the cytometer.

RESULTS

A sample of 2,468 patients with average age of 53 years were processed (ratio women:men 2:1). Urine culture detected 23% of positive urine samples. The predictor variables of UTI were: morphology of bacilli, bacteriuria ≥21 bacteria/µL, age ≥65 years, samples collected in the emergency service and hospitalization and preserving conditions. With 21 bacteria/µL as a cut-off point, we obtained a sensitivity of 93.3% and 94.5% negative predictive value, then reducing the samples to be cultured by 28.9% with 1.6% false negatives.

CONCLUSIONS

We consider that the UF-Series is a valid and accurate tool for the detection of UTI. Therefore, it could be used as screening method in the clinical practice prior to the urine culture, reducing culture requirement by approximately 30%, with a low false negative rate.

Sysmex UF-1000i flow cytometer to screen urinary tract infections: the URISCAM multicentre study

The new Sysmex UF-1000i analyzer - which incorporates bacteria morphology distinction - allows to automatically screen samples to be cultured at microbiology laboratories. We have evaluated the feasibility and accuracy of Sysmex UF-1000i to screen urinary tract infections (UTIs). A total amount of 2468 urine samples from six Spanish hospitals were analysed. Demographic and clinical data such as age, gender, source and sample type, preserving conditions, cytometer parameters (bacteria, leucocytes and bacteria morphology) as well as urine culture results (gold standard) were recorded. After applying data mining techniques, the variables of age, bacteria count and rod morphology were defined as predictive variables of UTIs. By using the UF-1000i in combination with a predictive algorithm of three decision rules, we could identify 94·9 and 47·4% positive and negative urine samples, respectively, with a negative predictive value of 97 and only 1·17% diagnostic error. This error was reduced down to 0·4% when contaminated samples were excluded. Our results show that flow cytometry parameters together with age, by means of a predictive algorithm model, can be used to screen UTIs. Its implementation would avoid culturing 38% of urine samples, and therefore, would reduce time to diagnosis with a discrete false negative ratio.

SIGNIFICANCE AND IMPACT OF THE STUDY

Fluorescent flow cytometry performance has recently spread for urine screening. However, controversy about cytometer results can be drawn from medical literature. This study shows the diagnosis accuracy of Sysmex UF-1000i analyzer by means of a group of decision rules encompassing both demographic variables (age) and cytometer parameters (bacteria, leucocytes and bacteria morphology). After applying the predictive algorithm, the UF-1000i could optimally identify 95% urinary tract infections with high negative predictive value and low diagnostic error. Implementation of UF-1000i would avoid culturing almost 38% of urine samples, thus reducing time to diagnosis, unnecessary antibiotic treatments and consequently improving cost-effectiveness.

[Microbiological study of infectious endophthalmitis with positive culture within a 13 year-period]

INTRODUCTION

Our objectives are to describe the microbial spectrum and antimicrobial susceptibility of isolates from patients with culture-proven endophthalmitis.

MATERIAL AND METHODS

Retrospective study of patients with microbiological diagnosis of endophthalmitis treated at the Ophthalmology Department of the General Hospital La Mancha Centro in the period 1996-2008. The identification of isolates was performed using the automated VITEK-2® and Api galleries (bioMérieux, Spain SA). The antimicrobial susceptibility was performed by the VITEK-2® system (bioMérieux, Spain SA), E-test strips (MIC Test Strip, Liofilchem, Italy) and Sensititre® YeastOne trading system (Trek Diagnostic Systems, Ohio, USA) for Candida species.

RESULTS

Forty four (70%) of 63 cases of endophthalmitis were culture positive. Gram-positive bacteria were much more common than gram-negative bacteria in both postoperative endophthalmitis (POE) and post-traumatic endophthalmitis (PTE). Staphylococcus epidermidis was predominant in POE, while Bacillus sp. predominated in the PTE; furthermore, the 75% of total fungal isolates corresponded to postraumatic cases. The isolated strains showed 100% susceptibility to vancomycin, ceftazidime and amikacin, while resistance to ciprofloxacin was greater than 15%. The empirical antifungal therapy failed in 50% of cases. The visual prognosis was significantly less favorable in the PTE.

CONCLUSIONS

Based on the susceptibility of our isolates, vancomycin, ceftazidime and amikacin are good choices for empirical treatment of endophthalmitis, unlike ciprofloxacin. We recommend conducting antifungal prophylaxis after penetrating ocular trauma in a rural environment.

[Antimicrobial resistance of the most frequently isolated microorganisms in the Hospital General La Mancha Centro between June 2009 and May 2010]

INTRODUCTION

During the last two decades an increased incidence of infections caused by multiresistant bacteria has been observed. The spread of these microorganisms in the hospital is a major therapeutic and epidemiological problem. The aim of this study was to determine local resistance patterns of microorganisms causative of multirresistant infections in patients admitted to our hospital.

METHODS

A retrospective study was designed, including Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Acinetobacter baumannii strains isolated from clinical and surveillance samples of patients admitted to the Hospital General La Mancha Centro, between June 2009 and May 2010.

RESULTS

The rate of S. aureus isolates resistant to oxacillin was 50%, with 0% resistance to vancomycin. The percentage of resistance to 3rd generation cephalosporins in E. coli and K. pneumoniae was 17 and 19%, respectively; the ESBL-production in enterobacterial strains was 15 and 19%, respectively, and the quinolone resistance was 41 and 28%, respectively. The resistance of P. aeruginosa to ceftazidime and imipenem was 30 and 40%, respectively. Most strains of A. baumannii studied came from a single multidrug-resistant clone, endemic in the ICU of our hospital.

CONCLUSIONS

Of particular concern is the high rate of MRSA, E. coli and K. pneumoniae ESBL producers and resistant to fluoroquinolones as well as P. aeruginosa multiresistant. A. baumannii isolates belong mainly to endemic multidrug-resistant clone from the ICU.

Outbreak of long-term intravascular catheter-related bacteremia due to Achromobacter xylosoxidans subspecies xylosoxidans in a hemodialysis unit

Achromobacter xylosoxidans is a rare cause of bacteremia. Over a 2-week period, A. xylosoxidans subsp. xylosoxidans was isolated from blood cultures of four hemodialysis patients with long-term intravascular catheters. A culture from one atomizer that contained diluted 2.5% chlorhexidine, which had been used to disinfect the skin, yielded A. xylosoxidans subsp. xylosoxidans. No further cases were diagnosed once the use of this atomizer was discontinued. Five outbreak-related strains from the four patients and the atomizer were tested by pulsed-field gel electrophoresis (PFGE) under XbaI restriction. The isolates from the first three patients and the atomizer had identical PFGE patterns, confirming the atomizer as the source of the outbreak. The strain isolated from the fourth patient had six more bands than the outbreak strain and was considered possibly related to the outbreak strain. All patients were treated with intravenous levofloxacin. The catheter was removed in only one patient. The three patients in whom the catheter was left in place were also treated with antibiotic lock therapy with levofloxacin. All four patients were cured. This is believed to be the first reported outbreak of central venous catheter-related bacteremia due to A. xylosoxidans and the second reported outbreak with this organism associated with chlorhexidine atomizers. The use of diluted chlorhexidine via atomizers can be dangerous for the care of venous catheters and should be called into question. Patients with long-term intravascular catheter-related bacteremia due to this organism can be treated successfully with systemic antimicrobial therapy in addition to antibiotic lock therapy without catheter removal.

[Ciprofloxacin resistance in gram negative bacilli. Epidemiologic aspects]

BACKGROUND

The aim of the present was to study the resistance to ciprofloxacin (CIP) in gram negative bacilli (April 1990-March 1992) and to determine the temporary distribution of the resistant strains by species, samples and departments.

METHODS

Seven thousand four hundred seventy-eight samples were studied. The identification and determination of the sensitivity was performed by the PASCO (Difco) system. Haemophilus spp. and Campylobacter spp. were excluded from the study. The microorganisms with CIM 2 mg/l were considered as resistant (CIPr).

RESULTS

Four hundred eighty-one CIPr isolations were identified (6.4%). With regard to the percentage of resistant strains, the species with the highest were: Providencia stuartii (50%); Pseudomonas cepacia (44.4%); Xanthomonas maltophilia (26.9%); Acinetobacter baumannii (25.8%); Pseudomonas aeruginosa (16%); Citrobacter freundii (12.5%); Serratia marcescens (8.4%); Enterobacter cloacae (5.8%) and Escherichia coli (4.3%). With respect to the absolute number of resistant strains, the most frequent resistant strains were: P. aeruginosa (205), E. coli (144), and A. baumannii (41). Isolation of E. coli and A. baumannii CIPr increased over the study period. Forty-four point five percent of the E. coli CIPr were of extrahospitalary origin; most of the A. baumannii (92.9%) and P. aeruginosa (77.6%) in contrast were of intrahospitalary origin.

CONCLUSIONS

P. aeruginosa, E. coli, and A. baumannii are the most frequently resistant species. The frequency of isolation of resistant strains of E. coli and A. baumannii significantly increased (p < 0.001) over the two years of the study.

[Evaluation of intestinal pathogenicity of Yersinia spp. strains isolated from human feces]

BACKGROUND

Yersinia enterocolitica is a human pathogen which an acts on the intestine by basically enteroinvasive mechanism. Its virulence has been related with the presence of a plasmid of 40-50 MD which codes a series of properties. There are strains of Y. enterocolitica and of other species assimilated to the Y. enterocolitica group which lack the virulence plasmid. In these cases there is a problem in evaluating the pathogenic ability on the intestine of these bacterias when isolated in faeces.

METHODS

A study of 30 Yersinia spp. strains including growth in a magnesium oxalate medium, Reg-Congo and agar (CR-MOX), sculine hydrolisis (Sc), pyrazinamidase activity (Pyz) and salicine fermentation (Sal) was performed. In addition, the presence of virulence plasmid (VP) was determined.

RESULTS

Twenty-two strains identified as Y. enterocolitica presented the virulence pattern (CR-MOX+, Pyz-, Sal/Sc-) and 21 were VP+. Seven strains isolated were CR-MOX-, Pyz+, Sal/Sc+ and VP- being typed as Y. fredericksenii (6) and Y. kristensenii (1). The remaining strain was CR-MOX- and VP- but Pyz, Sal/Sc were also negative, being identified as Y. enterocolitica.

CONCLUSIONS

By the tests referred the authors were able to identify and evaluate the pathogenicity of Yersinia spp. isolated in faeces. These techniques may be used in the microbiology laboratory as a method which aids to evaluate the diagnosis of intestinal infections caused by Yersinia spp.

Preoperative parental anxiety predicts behavioural and emotional responses to induction of anaesthesia in children

Parental presence at induction of anaesthesia is desirable if it makes the child happier and more cooperative. This study evaluated the emotional and behavioural responses of children to being accompanied by a parent at induction of anaesthesia in a paediatric day-care surgical centre. One hundred and thirty-four patients (aged 2-10 yr, ASA physical status I or II) were divided into two groups by day of surgery, to have a parent present at induction of anaesthesia (treatment group), or to be unaccompanied (control group). Before, and at one week after surgery, the child's fears and behaviour were scored by the Hospital Fears Inventory (HFI) and Behavioural Questionnaire (BQ), and parental anxiety by the Parents' Questionnaire (PQ) before and at one week after surgery. The Global Mood Scale (GMS) was used to assess the child's behaviour and the Visual Analogue Scale (VAS) to assess the parent's anxiety on arrival for surgery and at induction of anaesthesia. All patients and parents were disturbed by the experience, but to the same degree in the treatment and control groups. Subgroups of "calm" and "anxious" parents were identified by a median split of their preoperative VAS scores. Children in the "calm-treatment," "calm-control" and "anxious-control" subgroups were similarly upset at induction. Children in the "anxious-treatment" subgroup were the most disturbed at induction, and significantly more than those in the "anxious-control" subgroup. Preoperative parental anxiety levels also correlated with the child's fears and behaviour one week after surgery.(ABSTRACT TRUNCATED AT 250 WORDS)