Multilaboratory Comparison of Omadacycline MIC Test Strip to Broth Microdilution MIC against Gram-Negative, Gram-Positive, and Fastidious Bacteria.

The performance of the Liofilchem omadacycline MIC Test Strip (MTS) was evaluated in a multisite study. Three testing sites collected/tested clinical isolates and one site tested challenge isolates that totaled 175 S. aureus, 70 S. lugdunensis, 121 E. faecalis, 100 E. faecium, 578 Enterobacterales, 142 Haemophilus spp., 181 S. pneumoniae, 45 S. anginosus group, 35 S. pyogenes,and 20 S. agalactiae. MIC testing was performed by CLSI broth microdilution (BMD) and MTS. Fastidious isolates testing included BMD and MTS testing with both CLSI and EUCAST Mueller-Hinton Fastidious (MH-F). In addition, each site performed reproducibility for nonfastidious and fastidious isolates and QC by MTS and BMD. All BMD and MTS results for the QC strains were within expected ranges, with exception of one MTS HTM result for H. influenzae ATCC 49247. Among reproducibility isolates, omadacycline MTS results were within one dilution of the modal MIC for 95.2% of nonfastidious Gram-positive, 100% of Gram-negative, 99.3% and 98.5% of fastidious isolates tested on CLSI and EUCAST media, respectively. MTS results for all study isolates were within one doubling dilution of the CLSI BMD MIC for 98.9% of S. aureus, 100% of S. lugdunensis, 98.3% of E. faecalis, 100% of E. faecium, and 99.6% of Enterobacterales. Essential agreement rates for CLSI and EUCAST MH-F agar compared to CLSI BMD were 98.2% and 98.2%, for H. influenzae, 91.1% and 73.6%, for S. pneumoniae and 100% and 85-91.7% for other streptococcus species, respectively. Based on CLSI media, all categorical errors were minor errors and categorical agreement rates were >90% with exception of C. freundii, S. lugdunensis, E. faecalis, S. anginosus and S. constellatus.

Control of carbapenemase-producing Klebsiella pneumoniae: a region-wide intervention.

Starting in 2010, there was a sharp increase in infections caused by Klebsiella pneumoniae resistant to carbapenems in the Emilia-Romagna region in Italy. A region-wide intervention to control the spread of carbapenemase-producing K. pneumoniae (CPKP) in Emilia-Romagna was carried out, based on a regional guideline issued in July 2011. The infection control measures recommended to the Health Trusts (HTs) were: phenotypic confirmation of carbapenemase production, active surveillance of asymptomatic carriers and contact isolation precautions for carriers. A specific surveillance system was activated and the implementation of control measures in HTs was followed up. A significant linear increase of incident CPKP cases over time (p<0.001) was observed at regional level in Emilia-Romagna in the pre-intervention period, while the number of cases remained stable after the launch of the intervention (p=0.48). Considering the patients hospitalised in five HTs that provided detailed data on incident cases, a downward trend was observed in incidence after the release of the regional guidelines (from 32 to 15 cases per 100,000 hospital patient days). The spread of CPKP in Emilia-Romagna was contained by a centrally-coordinated intervention. A further reduction in CPKP rates might be achieved by increased compliance with guidelines and specific activities of antibiotic stewardship.

A Structured Training for Trans Anal Irrigation in Pediatric Patients Improves Outcomes and Reduce Failures: Results of an Interventional Multicenter Prospective Study.

BACKGROUND: Continence issues due to organic causes including previous colorectal surgery or neurological issues might benefit from Transanal irrigation (TAI) that proved to be highly effective but with a number of limitations including a relatively high discontinuation rates. Our study was aimed at evaluating the efficacy of an advanced protocol tailored to each patient to prevent dropout and increase satisfaction, independence, and quality of life. MATERIALS AND METHODS: This was a prospective, interventional, multicenter, nonrandomized study involving children aged 4-18 years with bowel dysfunction unresponsive to conventional treatments who required TAI. TAI was performed in accordance to the best standards of care with a total irrigation volume that was determined based on low emission X-Ray barium enemas performed at the very beginning of the study. All patients underwent training and assessments of continence, patients' perspectives and quality of life were performed at different timepoints from enrollment (T0) up to 6 months since TAI was introduced (T3). RESULTS: A total of 78 patients were enrolled. Male to female ratio was 1.4:1. Mean age at enrollment was 106.1 ± 42.8 months. Discontinuation was reported by 3 patients (3.8 %). Continence, satisfaction and a number of other outcome measures increased from baseline (T0) to the last visit (T3). In particular, mean Rintala total score increased linearly from 7.8 to 14.8 during the study period (T0 to T3 timepoints). On a multivariate analysis, the only parameter that proved to be inversely associated with continence as well as with other outcome measures was the use of laxatives at enrollment and during the study. CONCLUSIONS: This study has demonstrated the high efficacy of this innovative patient-tailored TAI protocol across all assessed scores. Of note, given the negative impact of laxatives, our findings suggest limiting their use in this patient population to further increase the efficacy of the procedure.

Comparison of the Staphylococcus QuickFISH BC test with the tube coagulase test performed on positive blood cultures for evaluation and application in a clinical routine setting.

Many studies demonstrate that delayed proper therapy in bloodstream infections caused by Staphylococcus aureus increases the mortality rate, emphasizing the need to shorten the turnaround time for positive blood cultures. Different techniques are currently available, from phenotypic methods to more complex tests such as matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF), real-time PCR (RT-PCR), and fluorescence in situ hybridization using peptide nucleic acid probes (PNA FISH). This study evaluated the performance of the Staphylococcus QuickFISH BC test (QFT), a novel FISH methodology, compared with the direct tube coagulase test (DTCT) on blood cultures exhibiting Gram-positive cocci in clusters. A total of 173 blood cultures collected from 128 different patients were analyzed using the DTCT, evaluated after both 4 and 24 h, and the QFT. A total of 179 isolates were identified using the Vitek2 system. Thirty-five out of 35 Staphylococcus aureus were correctly identified by the QFT (sensitivity = 100%), with a specificity of 100% (no green fluorescence was detected for strains different from S. aureus). The DTCT was positive after 4 h for 28 out of the 35 samples (sensitivity = 80%) and after 24 h for 31 out of the 35 samples (sensitivity = 88.57%). Among the remaining 144 isolates, one was then identified as Corynebacterium striatum and two as Micrococcus luteus. QFT identified 139 out of the 141 coagulase-negative staphylococci (CoNS) (sensitivity = 98.58%), showing again a specificity of 100% (no fluorescent red signals were detected for strains different from CoNS). We also discuss also the implementation process of this methodology in our setting, with particular emphasis on the workflow and the cost-effectiveness.

Autism and esophageal achalasia in childhood: a possible correlation? Report on three cases.

Chronic gastrointestinal symptoms are commonly reported in autistic patients. Dysphagia is often present, and it is generally related to behavioral eating disorders. The association between autism and esophageal achalasia has not been described in literature yet. We report our experience with three cases of autistic children we recently treated for esophageal achalasia. In the first case (a 14-year-old male), achalasia was diagnosed with barium swallow and esophageal manometry and was successfully treated with three pneumatic endoscopic dilatations (follow-up: 3 years). In the second case (a 12-year-old female), achalasia was diagnosed with barium swallow and esophageal manometry and was treated with Heller myotomy after two unsuccessful pneumatic endoscopic attempts (follow-up: 3 months). In the last case, a 15-year-old male underwent barium swallow and endoscopy that confirmed achalasia. He was treated with Heller myotomy, and he is asymptomatic at a 6-month follow-up. To our knowledge, this is the first report of a possible association between autism and esophageal achalasia. Because of the rarity of both diseases, their association in the same patient is unlikely to be casual even if speculation on their common etiology is impossible at present. This finding needs further confirmation, but it is sufficient, in our opinion, to indicate proper evaluation with barium swallow and/or manometry in any autistic children with eating difficulty.

Isolation and characterisation of colistin-resistant Enterobacterales from chickens in Southeast Nigeria.

OBJECTIVES: Resistance to colistin (CST) mediated by mobile genetic elements has had a broad impact worldwide. There is an intensified call for epidemiological surveillance of mcr in different reservoirs to preserve CST for future generations. In Nigeria, the poultry industry is a key livestock sector. This study was undertaken to screen putative colistin-resistant Enterobacterales (CST-r-E) from poultry birds in Southeast Nigeria and to determine the genetic relatedness of mcr-harbouring isolates. METHODS: Faecal and cloacal swab samples (n = 785) were collected from chickens in 17 farms located in three contiguous states in Southeast Nigeria between March-November 2018. Following selective culture, CST-r-E were isolated. Confirmation of CST resistance, antimicrobial susceptibility testing, molecular detection of genes mcr-1 to mcr-10, multilocus sequence typing (MLST) and randomly amplified polymorphic DNA (RAPD) analysis were performed on the isolates. A questionnaire was distributed to investigate the knowledge about CST and its use of chicken farm caretakers. RESULTS: Of the 785 samples evaluated, 45 (5.7%) were positive for 48 CST-r-E, among which 23 harboured the mcr-1 gene (22 Escherichia coli and 1 Klebsiella pneumoniae). In two E.coli isolates, a new allelic variant (mcr-1.22) was detected. RAPD analysis allowed the identification of 11 different fingerprints. MLST also revealed 11 STs, with 3 of them being novel. CONCLUSION: mcr has significantly spread in poultry birds of Southeast Nigeria, which poses a worrisome risk to veterinary and human health. Strategies to prevent indiscriminate use of CST in farms should be quickly adopted before CST resistance becomes a huge global health issue.

Outbreak of vancomycin-resistant Enterococcus spp. in an Italian general intensive care unit.

Following the identification of two clinical isolates of vancomycin-resistant enterococci (VRE) from intensive care unit (ICU) patients, a surveillance programme detected that six of eight ICU patients were colonised by VRE. Standard epidemic control measures were instituted in the ICU. During a 16-month period, 13 (2.5%) of 509 ICU patients had VRE-positive swabs upon admission, and 43 (8.7%) of 496 VRE-negative patients were colonised by VRE in the ICU. Patients who acquired VRE in the ICU had a longer ICU stay (p < 0.0001). No other statistically significant differences were demonstrated. Two patients had documented infection (infection/colonisation index, 3.6%; overall VRE infection frequency, 0.4%), but both recovered and were discharged. VRE colonisation did not increase the mortality rate. Automated ribotyping identified three clusters containing, respectively, the first 52 Enterococcus faecium isolates, two Enterococcus faecalis isolates, and two further isolates of E. faecium. Multilocus sequence typing demonstrated that two E. faecium isolates representative of the two ribotypes belonged to sequence types 78 and 18, and that these two isolates belonged to the epidemic lineage C1, which includes isolates with a wide circulation in northern Italy. The outbreak was controlled by continuous implementation of the infection control programme, and by the opening of a new unit with an improved structural design and hand-washing facilities.

Identification of coagulase-negative staphylococci other than Staphylococcus epidermidis by automated ribotyping.

As routine identification of coagulase-negative staphylococci is problematic, the performance of automated ribotyping was evaluated for identification of coagulase-negative staphylococci other than Staphylococcus epidermidis. In total, 177 isolates were tested, comprising 149 isolates from blood samples, 15 isolates that were not identified by internal transcribed spacer (ITS)-PCR in a previous study, and 13 reference strains. The identification results were compared with those obtained by the API 20 Staph system, with standard phenotypic and molecular methods as reference. Most (n = 166; 93.8%) isolates were identified correctly by automated ribotyping. For 61 isolates, API 20 Staph and ribotyping were in agreement, but for 105 isolates, ribotyping provided correct identification and API 20 Staph did not. Four isolates not identified by automated ribotyping were recognised correctly by API 20 Staph. The remaining seven isolates could not be identified by either of the two methods. Automated ribotyping was able to distinguish Staphylococcus capitis reliably from Staphylococcus caprae. The results demonstrate the value of automated ribotyping for identification of coagulase-negative Staphylococcus (CoNS) isolates from human sources and may help to clarify the clinical relevance of CoNS species. In addition, automated ribotyping was able to detect polymorphisms that may be useful for epidemiological purposes within S. capitis, Staphylococcus hominis, Staphylococcus haemolyticus, Staphylococcus simulans, S. caprae, Staphylococcus warneri, Staphylococcus lugdunensis, Staphylococcus schleiferi, Staphylococcus sciuri, Staphylococcus pasteuri and Staphylococcus xylosus.

Evaluation of carbapenem-resistant Enterobacteriaceae in an Italian setting: report from the trench.

The spread of carbapenem resistant Enterobacteriaceae (CRE) has recently become a matter of concern in public health, mainly due to the wide distribution of carbapenemase genes. Italy is a country considered endemic for the spread of blaKPC Klebsiella pneumoniae (KP). The aim of this study was to depict the epidemiological trend of CRE in one Italian hospital over a long period (3 years surveillance, from May 2011 to April 2014). Based on defined MIC cut-off for specific carbapenems, 164 strains isolated from 146 different patients were analyzed both phenotypically and genotypically to establish the resistance genes. Molecular typing was performed using the RAPD technique. 77 strains were demonstrated to harbor the blaKPC gene (73 KP, 4 Escherichia coli - EC), 51 strains the blaVIM gene (44 KP, 3 EC, 2 Enterobacter cloacae and 2 Klebsiella oxytoca), 8 the blaNDM gene (3 KP, 4 EC and one Providencia stuartii), 3 the blaOXA-48 gene (2 KP, 1 EC), whereas 25 out of the 164 isolates (of different genera and species) had a negative multiplex-PCR amplification for all the targets tested. 39 out of the 164 strains analyzed (23.8%) revealed discrepancies between the MICs obtained with automated instrument and gradient MICs of more than two logs of difference; the broth microdilution provided a better agreement with the results obtained with the gradient MIC. The use of RAPD allowed to distinguish different clusters, closely related, both for blaKPC and for blaVIM KP.

Comparative in vitro activity of silver sulfadiazine, alone and in combination with cerium nitrate, against staphylococci and gram-negative bacteria.

Silver sulfadiazine (SSD), a topical antimicrobial agent, has been widely used for the prophylaxis and treatment of burn infections during the past 30 years. We determined the antimicrobial activity of SSD, alone and in combination with cerium nitrate (CN), gentamicin and amikacin against 130 recent clinical isolates, including multiresistant bacteria such as methicillin-resistant Staphylococcus aureus (MRSA) or Pseudomonas aeruginosa. The overall activity of SSD was good against all the tested strains and it was particularly high against MRSA (MIC90 100 microg/ml). CN showed no inhibitory effect, even up to 800 microg/ml, on bacterial strains tested. The combination of SSD and CN was as active as SSD alone. In conclusion, SSD has a broad spectrum of activity at concentrations lower than those commonly used in clinical preparations. All strains were inhibited by less then one-fiftieth of the SSD "in use" concentration (10 mg/ml). Our data confirm the efficacy of this topical agent in the prevention and treatment of infections in burns or other surgical wounds and suggest its possible use in clearing staphylococcal carriage as an alternative to mupirocin.

Rapid drug susceptibility of Mycobacterium avium complex using a fluorescence quenching method.

Mycobacteria Growth Indicator Tube (MGIT) is a recently introduced rapid growth detection method which uses an oxygen quenched fluorescent indicator. The present study evaluated the ability of this new method to determine the drug susceptibility of Mycobacterium avium complex (MAC). Thirty strains recovered from patients with AIDS were tested for susceptibility to clarithromycin, rifabutin, ciprofloxacin, azithromycin and amikacin using MGIT. Results were compared to susceptibilities determined by the agar dilution method. The results obtained showed a 100% correlation between MGIT and the agar dilution method for rifabutin and clarithromycin. There was a 100% correlation between the two methods for azithromycin against 27 strains. MGIT was well correlated with the agar dilution method for detecting resistance to clarithromycin, rifabutin and azithromycin in 4 days, but the correlation was poor when susceptibilities to ciprofloxacin and amikacin were determined. This rapid method is non-radiometric, noninvasive and does not require any special instruments.

Bactericidal activity of Pistacia lentiscus mastic gum against Helicobacter pylori.

In this study we evaluated the antibacterial activity of mastic gum, a resin obtained from the Pistacia lentiscus tree, against clinical isolates of Helicobacter pylori. The minimal bactericidal concentrations (MBCs) were obtained by a microdilution assay. Mastic gum killed 50% of the strains tested at a concentration of 125 microg/ml and 90% at a concentration of 500 microg/ml. The influence of sub-MBCs of mastic gum on the morphologies of H. pylori was evaluated by transmission electron microscopy. The lentiscus resin induced blebbing, morphological abnormalities and cellular fragmentation in H. pylori cells.

Extended-spectrum beta-lactamase-producing Enterobacteriaceae in an Italian intensive care unit: clinical and therapeutical remarks.

In this study we evaluated the prevalence of Enterobacteriaceae and the epidemiology of ESBL+ microorganisms in an ICU of our Institution over a 5-year period and analyzed the clinical features and outcomes of the infections caused by these microorganisms. The most frequent ESBL+ isolate was Proteus mirabilis (69 isolates, 58%); a high rate of positive results in the double-disk synergy test (DDS) was also recognized for Klebsiella pneumoniae (52 isolates, 51%), whereas this phenomenon was observed less frequently in other species. In 312 cases the isolated microorganism was considered to be the cause of infection; we documented 103 wound infections, 89 UTIs, 62 LRTIs, 30 primary bacteremias, 27 infections of indwelling catheters and 1 CNS infection. The overall mortality rate due to ESBL+ strains was 1%, compared with 10.6% rate caused by ESBL-negative Enterobacteriaceae. This could be explained because ESBL+ strains caused mostly localized infections (wound infections and UTIs), whereas systemic or severe infections were sustained by ESBL-negative strains, and therapy with carbapenems was started promptly after ESBL+ isolation (always within 24h after strain isolation).

99mTc-MIBI radioguided surgery for limited invasive parathyroidectomy.

We report the preliminary results obtained with the intraoperative MIBI-guided gamma probe in a group of 9 patients with primary hyperparathyroidism (pHPT). These patients were selected for limited invasive parathyroid surgery on the basis of a preoperative imaging protocol consisting of a pertechnetate & perchlorate/MIBI scan combined with neck ultrasonography (US). In the operating room 50-70 MBq MIBI was injected 30 to 45 min before parathyroidectomy. The radioactivity was measured intraoperatively at three sites: parathyroid (P), thyroid (T), and background (B). The P/B, P/T, and T/B ratios were calculated. The T/B ratio was relatively constant (range, 1.5-1.8; mean, 1.6), while a wide variability was observed both for P/T ratio (range, 1.2-2.3; mean, 1.7) and P/B ratio (range, 2.1-4.0; mean, 2.9). At surgery single enlarged parathyroid glands were easily identified by means of intraoperative MIBI-guided gamma probe. Moreover, the gamma probe allowed us to perform a limited 2-2.5 cm neck incision in eight patients affected by parathyroid adenoma. In the remaining patient a parathyroid carcinoma was diagnosed and a bilateral neck exploration was performed. The intraoperative MIBI gamma probe seems to be a useful aid when limited invasive parathyroid surgery is performed.

Typing of methicillin-resistant Staphylococcus aureus (MRSA) strains from an intensive care unit by random amplified polymorphic DNA (RAPD).

The identification and control of methicillin-resistant Staphylococcus aureus (MRSA) is of primary concern in intensive care units (ICUs) worldwide. The introduction and circulation of particular strains is best studied by genomic procedures and random amplified polymorphic DNA (RAPD) is well suited for this task. In this study 14 isolates of MRSA, obtained over an 8 month period from the blood cultures of 12 patients in an ICU at our hospital, were typed by RAPD method using seven primers. Three separate groups were distinguished and clustering of certain types in time and space was noted. These results suggest that although different strains of MRSA were involved in this outbreak, cross-infection with individual types occurred. RAPD fingerprinting is a relatively simple method that allows epidemiologic investigation of MRSA outbreaks in hospital infection.

Lactobacillus casei endocarditis in an intravenous heroin drug addict: a case report.

A 24-year-old HIV negative unemployed intravenous heroin addict with teeth in poor condition was admitted to hospital with left hemiparesis; CT scan of the brain revealed a hypodense area in the right parietal region. He was apyrexial with marked leukocytosis and raised ESR, had an aortic diastolic murmur and an echocardiogram showed marked aortic insufficiency with possible small vegetations on the anterior leaflet of the mitral valve. Lactobacillus Casei was isolated from repeated blood cultures. Therapy with penicillin G together with netilmicin for 6 weeks led to improvement of his clinical status and an echocardiogram on discharge showed clear improvement. Regression of the cerebral lesions was also demonstrated on CT scan. We conclude that lactobacillus species should be sought in all haemoculture negative endocarditis in the presence of tooth disease.

[Methicillin-resistant Staphylococcus aureus (MRSA) in an intensive care unit: a one-year survey]. / Colonizzazioni e infezioni da Staphylococcus aureus meticillino-resistente (SAMR) in una terapia intensiva polivalente: analisi su un anno di osservazione.

Methicillin-resistant Staphylococcus aureus (MRSA) is frequently isolated in nosocomial outbreaks. In our study, we analysed the occurrence of colonisation and infection in an Intensive Care Unit of our hospital during a 12-month period. We also evaluated the possibility of using automated ribotyping as a molecular method in order to type the isolates. Twice a week a nasal swab and a rectal swab were performed on all patients; from ventilator-assisted patients, a sputum culture was also taken. All the MRSA isolated were identified by using commonly phenotypic procedures and on all isolates susceptibility tests were performed. An automated ribotyping using EcoRI was also done. Out of 292 patients enrolled in the study, 205 were never colonised (group N); among the other 87 who were colonised by MRSA (29.8%), 40 patients (group A) were MRSA carriers at the time of admission, while 47 (group B) were colonised in the ICU. Twenty-seven patients (11 from group A, 15 from group B and 1 from group N) developed 31 infections due to MRSA. Patients from group A exhibited, as a rule, worse clinical conditions than those from the other two groups. For the former group, MRSA infection was frequently systemic (sepsis), while in group B pneumonia was the predominant infection. The prevalence of colonisations in our study was 30%, which is a value comparable to those presented by other authors in similar cases. MRSA colonisation is a necessary condition for subsequent infections in almost all cases, with an average lag of 7 days. Susceptibility tests were non-discriminating among the isolates: all the strains were susceptible to glycopeptides; nearly all of them were resistant to erythromycin, clindamycin, ciprofloxacin and gentamicin. Automated ribotyping allowed us to distinguish 12 different ribogroups, the most frequent of which was composed of 146 isolates. In our study, this molecular method was able to define a possible endemic clone that should be better investigated by using methods with a higher discriminatory power, such as RAPD or PFGE. The method that we employed is highly reliable, easy to perform and not time-consuming. In our opinion, it could be the method of choice in the first screening of high numbers of isolates.

Widespread carbapenem resistant Acinetobacter baumannii clones in Italian hospitals revealed by a multicenter study.

Population diversity, susceptibility to antibiotics including carbapenems of 277 Acinetobacter baumannii strains collected in 17 Italian hospitals over a 6-months' period was assessed. Semi-automated rep-PCR was used for screening strains for genotypic relatedness. AFLP analysis and MLST were used as definitive methods for strain, species and/or clone identification. Among the 277 strains, 49 rep-PCR types were distinguished with four types (1-4) predominant, indicating both intra- and interhospital spread. AFLP analysis allowed to distinguish 51 types and largely confirmed rep-typing results. Isolates with predominant rep-types 1 and 2 (in 3 and 9 hospitals) were allocated to EU clones I and II, respectively. Rep-type 3 (8 hospitals) belonged to a new clone ("Italian clone"). Rep-type 4 was found in 2 neighbouring hospitals. Two isolates from 2 locations belonged to EU clone III. Twenty-five isolates were identified by AFLP-analysis to A. pittii, emphasizing misidentification by phenotypic methods. MLST confirmed clone identification by AFLP; demonstrating also that the "Italian clone" was ST78, recently detected in different Mediterranean countries. Multidrug resistance, defined as resistance to 9 out of the 11 drugs tested, was common in 10 out of 17 hospitals. The high prevalence of carbapenem resistance was associated with OXA-58 found in 9 out of the 10 hospitals. A high percentage of noted very major errors in susceptibility testing, especially for amikacin and meropenem, was probably due to heteroresistant strains. The occurrence of carbapenem and multidrug resistance in A. baumannii was mainly confined to a limited number of clonal lineages of A. baumannii.

Review of the Uruguayan Kidney Allocation System: the solution to a complex problem, preliminary data.

The National Kidney Transplant Program with cadaveric donors is based on centralized and unique waitlist, serum bank, and allocation criteria, approved by Instituto Nacional de Donación y Trasplante (INDT) in agreement with clinical teams. The median donor rates over last 3 years is 20 per million population and the median number of waitlist candidates is 450. The increased number of waiting list patients and the rapid aging of our populations demanded strategies for donor acceptance, candidate assignment, and analysis of more efficient and equitable allocation models. The objectives of the new national allocation system were to improve posttransplant patient and graft survivals, allow equal access to transplantation, and reduce waitlist times. The objective of this study was to analyze variables in our current allocation system and to create a mathematical/simulation model to evaluate a new allocation system. We compared candidates and transplanted patients for gender, age, ABO blood group, human leukocyte agents (HLA), percentage of reactive antibodies (PRA), and waiting list and dialysis times. Only 2 factors showed differences: highly sensitized and patients >65 years old (Bernoulli test). An agreement between INDT and Engineering Faculty yielded a major field of study. During 2008 the data analysis and model building began. The waiting list data of the last decade of donors and transplants were processed to develop a virtual model. We used inputs of candidates and donors, with outputs and structure of the simulation system to evaluate the proposed changes. Currently, the INDT and the Mathematics and Statistics Institute are working to develop a simulation model, that is able to analyze our new national allocation system.