Vaccine selection for COVID-19 by AHP and novel VIKOR hybrid approach with interval type-2 fuzzy sets.

Decisions in the health industry have a significant impact on human lives. With the COVID-19 pandemic, a global war is being waged. Vaccination is a critical component in this fight. The governments are attempting to offer their citizens the best vaccine for the public based on limitations. However, due to the unique characterizations of countries and the people who live in the country, the definition of "the ideal vaccination" is indefinite. Fuzzy set theory has been an ideal tool to cope with problems involving imprecise information such as the meaning of "ideal" in this case. In this study Interval Type-2 Fuzzy Sets (IT2FSs) will be used to describe uncertainty. This IT2FS structure will be the framework of the AHP (Analytic Hierarchy Process), to determine the criteria weights, and the VIKOR (VIseKriterijumska Optimizacija I Kompromisno Resenje), to generate a set of optimal choices. The main objective of this study is to sustain the necessary effect of uncertainty of fuzzy sets via the Interval Type-2 Fuzzy (IT2F) metric to the VIKOR method and thus propose an extended VIKOR. The presented new approach will be applied to the problem of vaccine selection for COVID-19. Hence, for the first time in the literature, an application with a multilevel hierarchy will be used in IT2FAHP-VIKOR. Also, obtained optimal solution set with this hybrid framework will be compared with fuzzy AHP-VIKOR and the rankings evaluated with the IT2FTOPSIS (Technique for Order of Preference by Similarity to Ideal Solution) and sensitivity analysis will be performed.

Exometabolomic analysis of susceptible and multi-drug resistant Pseudomonas aeruginosa.

Multidrug resistant (MDR) Pseudomonas aeruginosa strains have recently become one of the major public health concerns worldwide leading to difficulties in selecting appropriate antibiotic treatment. Thus, it is important to elucidate the characteristics of MDR isolates. Herein, we aimed to determine the unique exometabolome profile of P. aeruginosa clinical isolates in monocultures that comprise high resistance to multiple antibiotics, and compare the differential metabolite profiles obtained from susceptible isolates by using GC/MS. Our results showed that partial least square-discriminant analysis (PLS-DA) score plot clearly discriminated the MDR and susceptible isolates indicating the altered exometabolite profiles, and highlighted the significantly enriched levels of trehalose and glutamic acid in MDR isolates. Expression of trehalose synthase (treS) was also 1·5-fold higher in MDR isolates, relatively to susceptible isolates. Overall, our study provides insights into the distinct footprints of MDR P. aeruginosa isolates in mono-culture.

Knowledge and attitude regarding bisphosphonates and related osteonecrosis among Turkish dentist: A cross sectional study.

BACKGROUND AND AIMS: Bisphosphonates (BPs), the antiresorptive drugs, can cause osteonecrosis of the jaws. Having adequate knowledge about BPs and bisphosphonate-related osteonecrosis of the jaw (BRONJ) is very important to prevent complications. In this study, we aimed to determine the level of knowledge of dentists about BPs and BRONJ in Turkey and also aimed to share the results with health authorities to plan new education strategies. MATERIALS AND METHODS: A questionnaire consisting of 20 questions and two parts was used to determine the knowledge level, attitude, and training needs of the dentists. Answers to all questions were analyzed with descriptive statistics, and using Pearson Chi-square and Kruskal-Wallis tests. P values <0.05 were considered statistically significant. RESULTS: A total of 620 general and specialist dentists working in three different sectors and four different cities agreed to participate in the study. Statistically, more knowledge about BPs and BRONJ was observed in dentists who have less than 10 years of experience than those who have over 10 years, specialist dentists than general dentists, and those who working in university hospitals than in other sectors. In general, the rate of those who know BPs is 16.8%, the rate of those who know BRONJ is 20.2%. CONCLUSIONS: Although the use of BPs increases day by day, the awareness of BPs and BRONJ among the dentists is insufficient. However, periodically organizing postgraduate training programs on this subject will increase the awareness and level of knowledge.

Detection of radiotherapy-related damage in head and neck cancer patients by evaluating volumetric changes in lacrimal gland, nasolacrimal duct and computed tomography attenuation changes in lens.

PURPOSE: In our study, we aimed to evaluate the change in attenuation of lens in CT images, volumetric changes, in lacrimal gland (LG) and nasolacrimal duct (NLD) of the patients receiving radiotherapy for brain or head & neck tumor. Additionally, the correlation between these changes and radiation dose data were investigated. METHODS: Patient simulation CT images and control CT images were used to evaluate the volume and attenuation changes. Pre- and post-treatment MR and CT images were used to evaluate radiation-induced volumetric alterations in NLD and LG, respectively. Radiation therapy was given to a total dose of 54-70 Gy with conventional fractionated scheme using intensity-modulated radiotherapy technique (IMRT). Dose volume parameters were evaluated via dose volume histograms (DVHs). RESULTS: Dose volume parameters, volume and densities of 59 lenses (L), 60 LG and 60 NLD of 30 patients were retrospectively assessed. The median LG volume was significantly lower in the post-treatment images (p < 0.001), whereas the median volumes of NLD in pre- and post-RT images were similar. The Hounsfield unit (HU) numbers of lenses were significantly lower on post-RT CT images (p < 0.001). No statistically significant correlation was found between dose parameters and volume or HU changes (p = 0.054-0.817). CONCLUSION: It was observed that the attenuation of lenses and lacrimal gland volume significantly lowers following radiation. However, these alterations were not found to be correlated with dose.

Recombinant human thyrotropin versus thyroid hormone withdrawal in differentiated thyroid carcinoma follow-up: a single center experience.

Introduction: Our goal was to evaluate and compare the diagnostic utility of thyroid hormone withdrawal (THW) and recombinant thyroid-stimulating hormone (rhTSH) methods in detecting recurrence/persistence (R/PD) of differentiated thyroid carcinoma (DTC). Methods: The study included 413 patients with DTC who underwent total thyroidectomy and had remnant ablation. DxWBS, s-Tg levels, R/PD were evaluated retrospectively. A s-Tg level≥2 ng/mL was considered as "positive s-Tg". Results: DxWBS and s-Tg levels were evaluated with rhTSH in 116 and THW in 297 subjects, respectively. The sensitivity and specificity of "positive s-Tg" for R/PD in THW group were 77.3% and 92.7%, with 90.3% accuracy, respectively. The sensitivity and specificity of "positive s-Tg" for R/PD in rhTSH group were 58.8% and 100% with 93.9 % accuracy, respectively. An uptake outside thyroid bed at WBS showed a sensitivity of 17.1%, specificity of 100% for R/PD with 89.4% accuracy in THW group. An uptake outside thyroid bed at WBS showed a sensitivity of 7.7%, specificity of 100% for R/PD with 88.8% accuracy in rhTSH group. Conclusion: Method of TSH stimulation did not influence the reliability of DxWBS. The "positive s-Tg level" had a higher sensitivity with THW when compared to rhTSH in detecting R/PD.

Evaluating the predictive value of quantec rectum tolerance dose suggestions on acute rectal toxicity in prostate carcinoma patients treated with IMRT.

AIM: To investigate the predictive value of convenience of rectum dosimetry with Quantitative Analysis of Normal Tissue Effects in the Clinic (QUANTEC) dose limits, maximum rectum dose (Dmax), total rectal volume (TVrectum), rectal volume included in PTV (VrectumPTV) on Grade 2-3 acute rectal toxicity for utilization in clinical practice. BACKGROUND: Numerous previous data have reported frequent acute proctitis after external-beam RT of prostate cancer. Predicting toxicity limited with dose information is inadequate in clinical practice due to comorbidities and medications used. MATERIALS AND METHOD: Sixty-four non-metastatic prostate cancer patients treated with IMRT were enrolled. Patients were treated to a total dose of 70-76 Gy. Rectal dose volume histograms (DVH) of all patients were evaluated retrospectively, and a QUANTEC Score between 0 and 5 was calculated for each patient. The correlation between the rectal DVH data, QUANTEC score, TVrectum, VrectumPTV, rectum Dmax and Grade 2-3 rectal toxicity was investigated. RESULTS: In the whole group grade 1, 2 and 3 acute rectal toxicities were 25%, 18.8% and 3.1%, respectively. In the DVH data, rectum doses of all patients were under RTOG dose limits. Statistically significant correlation was found between grade 2-3 rectal toxicity and TVrectum (p = 0,043); however. It was not correlated with QUANTEC score, VrectumPTV and Dmax. CONCLUSION: Our results were not able to show any significant correlation between increasing convenience with QUANTEC limits and lower rectal toxicity. Conclusively, new dosimetric definitions are warranted to predict acute rectal toxicity more accurately in prostate cancer patients during IMRT treatment.

Involvement of spinal cannabinoid receptors in the antipruritic effects of WIN 55,212-2, a cannabinoid receptor agonist.

BACKGROUND: Cannabinoids have been used for their analgesic and euphoric effects for millennia, but recently the antipruritic effects of cannabis have been discovered. Considering the similarities between pain and itch sensations, we hypothesized that cannabinoid receptors may play a role in the antipruritic effects of cannabinoids. AIM: To analyse the role of the spinal cannabinoid receptors, CB1 and CB2, in the antipruritic effects of the cannabinoid agonist WIN 55,212-2. METHODS: Male Balb/c mice weighing 20-30 g were used. Scratching behaviour in the mice was produced by injection of serotonin 5 µg/50 µL intradermally into the nape of the neck. Scratching of the site of injection by the hind paws was video-recorded for 30 min. After testing different doses of WIN 55,212-2 [1, 3 and 10 mg/kg intraperitoneally (IP)], the effects of the CB1 receptor antagonist, AM-251 [1 µg/mouse administered intrathecally (IT)] and the CB2 receptor antagonist AM-630 (4 µg/mouse IT) on the antipruritic effects of WIN 55,212-2 were studied using a rotarod apparatus. RESULTS: WIN 55,212-2 (1, 3 or 10 mg/kg IP) dose-dependently decreased serotonin-induced scratches. The receptor antagonist CB1 partially reversed the effects of WIN 55,212-2 (P < 0.05); whereas CB2 had no statistically significant effect. WIN 55,212-2 impaired motor function only at the highest dose given (10 mg/kg, P < 0.05). CONCLUSIONS: Our findings support prior researches indicating that cannabinoids exert antipruritic effects. Moreover, our results show that the antipruritic effects of cannabinoids are partially mediated by spinal CB1 receptors.

Obesity-related cardiovascular behavior in children.

OBJECTIVE: Obesity is a chronic metabolic disorder and may associate with cardiovascular geometrical, structural and functional changes. The aim of this study is to assess the relationship between body mass index (BMI), body surface area (BSA) and arterial-ventricular elasticity (Ea and Ees respectively) and cardiovascular coupling and myocardial wall stress and fiber stress in obese children. PATIENTS AND METHODS: Sixty non-obese healthy children with BMI <85th percentile aged 6-17 years and 65 age and sex-matched children with BMI of ≥95th percentile, were included in the study. Beside cardiac systolic and diastolic functions, left verntricular (LV) systolic and diastolic dimensions and volumes (LVDs, LVDd, LVVs, LVVd respectively), LV mass (LVM), LV end-systolic pressure (LVESP), meridional end-systolic wall stress (ESWm), myocardial fiber stress (MFS), Midwall Shortening Fraction (SFmid), heart rate corrected circumferential fiber shortening (VCFc), predicted mid wall fiber shortening for a measured fiber stress (mid wall VCFc), right ventricular (RV) and LV work index (RVWI, LVWI), LV relative wall thickness (LVRWT), arterial elastance (Ea), LV end-systolic elastance (Ees) and end-systolic pressure volume relationship (ESPVR) were calculated. RESULTS: LVDs and LVDd, LV mass (LVM), ESWSm, MFS, SF mid, Midwall VCFc and LVWI found to be significantly (p<0.001) higher, while Ea, Ees, ejection fraction (EF), fractional shortening (FS), VCFc-ESWS, RVWI, ESWSm/LVVs, LV end-systolic pressure (Pes)/LVVs and LVM/LVVd values were significantly (p<0.001) lower among obese group. By increasing age and BMI the Ea and Ees, ESWSm/LVVS and RVWI decrease; while LVDd, LVVd and stroke volume (SV) values increase. There was a reverse-relation between BMI percentiles and EF and FS.

Serum chitotriosidase levels in cancer patients undergoing high dose chemotherapy and stem cell transplantation.

OBJECTIVE: Human chitotriosidase (ChT) is an active chitinase expressed by activated phagocytes. Increased ChT activity has been reported in systemic Candida albicans infections and in Gram-negative and Gram-positive bacterial infections, indicating that an increase in ChT activity reflects phagocyte activation. The aim of this study was to determine the changes in serum ChT activity in patients who underwent high dose chemotherapy (HDC) and stem cell transplantation (SCT), who are at an increased risk for fungal and bacterial infections due to depression of the immune system during the neutropenic period. PATIENTS AND METHODS: A total of 55 SCT patients were included in the study. Serum ChT activity was determined before the initiation of HDC and during the neutropenic period after hematopoietic stem cell reinfusion on post-transplant first, fifth and tenth days. RESULTS: Chitotriosidase levels before transplantation were significantly lower than the results at first, fifth and tenth days post-hematopoietic stem cell reinfusion. CONCLUSIONS: Although the number of neutrophils was low, ChT enzyme activity was high in newly produced granules of neutrophils. Chitotriosidase may be supplemented as a drug for preventing and treating infections in the near future.

Immobilization of acetylcholinesterase on Pt(II) and Pt(IV) attached nanoparticles for the determination of pesticides.

Pt(ii) and Pt(iv)-tagged nanoparticles have been synthesized according to the template method for the identification of pesticides. Their morphologies have been investigated using scanning electron microscopy and characterized by means of spectral measurements. Then, acetylcholinesterase (AChE) was immobilized onto the nanoparticles. The AChE immobilized Pt(ii) and Pt(iv)-tagged nanomaterials show high reusability and storage capacity. The catalytic activity of AChE followed Michaelis-Menten kinetics. Assays for enzyme activity measurements demonstrate that the nanospheres tagged with Pt(ii) have a much better performance than those with Pt(iv). Furthermore, whether or not there was any interaction between the immobilized enzyme and 1-naphthyl-N-methylcarbamate, which is a carbamate insecticide, was examined.

Arterial and left ventricular end-systolic elastance in normal children.

OBJECTIVE: Assessing the left ventricular (LV) functions in Pediatric Intensive Care Unit, and those pediatric patients with compromised ventricular performance or enhanced systolic or diastolic load e.g. congestive heart failure, hypertension, dilated/hypertrophic cardiomyopathies is a real challenge. Currently used noninvasive methods fail giving quantitative measures to asses cardiac performance and do not allow evaluation of ventriculo-arterial interaction. Non-invasive method of cardiovascular performance determination by measuring left ventricle end-systolic elastance (Ees), arterial elastance (Ea) and the ventriculoarterial coupling (VAC), though interaction between LV and arterial network, is possible. PATIENTS AND METHODS: Hundred and forty two otherwise normal children (1 week to 17 years old) were randomly selected. Routine transthoracic echocardiographic and Doppler studies were carried out by an experienced pediatric cardiologist. The results have been evaluated statistically. RESULTS: We found that the Ea and Ees(sb) show powerful negative correlation with BSA (r = -0.65, -0.72 respectively) of the children. CONCLUSIONS: We suggest that this simple measurement method may be applied at bedside to evaluate ventricular performance of the children.

Endothelium-dependent vasorelaxant effect of Alchemilla vulgaris methanol extract: a comparison with the aqueous extract in rat aorta.

We aimed to investigate the vascular effects of methanol extract (ME) and aqueous extract (AE) of Alchemilla vulgaris (Rosaceaea). Increasing concentrations of the ME (0.01-10 mg/mL) produced relaxations in noradrenaline (NA: 10⁻6 M) and K⁺ (40 mM) precontracted aortas while contractions were obtained with the AE (0.01-10 mg/mL). Responses to the ME were inhibited in the presence of putative inhibitors of endothelial vasodilators or after removal of the endothelium. Pretreatment of aortic rings with the ME (10 mg/mL, 20 min) reduced the maximal contractions to NA and K⁺, whereas an enhanced contractility was observed with the AE (10 mg/mL, 20 min). Total flavonoid content was higher in the ME than in the AE. Quercetin was determined particularly high in the ME while gallic acid was high in the AE. Our results indicated that the ME of A. vulgaris displays favourable vascular effects via endothelium-dependent mechanisms.

Positron emission tomography/computed tomography in locally advanced breast cancer.

Locally advanced breast cancer (LABC) is a relatively small group of breast cancer, but is significant because it carries a higher risk of locoregional recurrence and distant metastasis. The accepted approach for these patients is neoadjuvant chemotherapy before surgery as determining the response to therapy in the early stages is of critical importance in respect of the approach taken to the disease. Positron emission tomography/computed tomography (PET/CT) using fluorine-18-fluorodeoxyglucose (18F-FDG) is currently used for staging, restaging and response monitoring in breast cancer. The areas of use of FDG PET/CT in LABC can be summarised as the evaluation of response to neoadjuvant chemotherapy in the early stage in particular, and the determination of unexpected areas of metastasis not detected by standard imaging techniques. There are current ongoing studies on promising new PET radiopharmaceuticals apart from FDG.

Relationships between Podolic cattle breeds assessed by single nucleotide polymorphisms (SNPs) genotyping.

Italian Maremmana, Turkish Grey and Hungarian Grey breeds belong to the same Podolic group of cattle, have a similar conformation and recently experienced a similar demographic reduction. The aim of this study was to assess the relationship among the analysed Podolic breeds and to verify whether their genetic state reflects their history. To do so, approximately 100 single nucleotide polymorphisms (SNPs) were genotyped on individuals belonging to these breeds and compared to genotypes of individuals of two Italian beef breeds, Marchigiana and Piemontese, which underwent different selection and migration histories. Population genetic parameters such as allelic frequencies and heterozygosity values were assessed, genetic distances calculated and assignment test performed to evaluate the possibility of recent admixture between the populations. The data show that the physical similarity among the Podolic breeds examined, and particularly between Hungarian Grey and Maremmana cattle that experienced admixture in the recent past, is mainly morphological. The assignment of individuals from genotype data was achieved using Bayesian inference, confirming that the set of chosen SNPs is able to distinguish among the breeds and that the breeds are genetically distinct. Individuals of Turkish Grey breed were clearly assigned to their breed of origin for all clustering alternatives, showing that this breed can be differentiated from the others on the basis of the allelic frequencies. Remarkably, in the Turkish Grey there were differences observed between the population of Enez district, where in situ conservation studies are practised, and that of Bandirma district of Balikesir, where ex situ conservation studies are practised out of the original raising area. In conclusion, this study demonstrates that molecular data could be used to reveal an unbiased view of past events and provide the basis for a rational exploitation of livestock, suggesting appropriate cross-breeding plans based on genetic distance or breeding strategies that include the population structure.

Genetic variation and relationships among Turkish water buffalo populations.

The genetic variation and relationships among six Turkish water buffalo populations, typical of different regions, were assessed using a set of 26 heterologous (bovine) microsatellite markers. Between seven and 17 different alleles were identified per microsatellite in a total of 254 alleles. The average number of alleles across all loci in all the analysed populations was found to be 12.57. The expected mean heterozygosity (H(e)) per population ranged between 0.5 and 0.58. Significant departures from Hardy-Weinberg equilibrium were observed for 44 locus-population combinations. Population differentiation was analysed by estimation of the F(st) index (values ranging from 0.053 to 0.123) among populations. A principal component analysis of variation revealed the Merzifon population to show the highest differentiation compared with the others. In addition, some individuals of the Danamandira population appeared clearly separated, while the Afyon, Coskun, Pazar and Thural populations represented a single cluster. The assignment of individuals to their source populations, performed using the Bayesian clustering approach implemented in the structure 2.2 software, supports a high differentiation of Merzifon and Danamandira populations. The results of this study are useful for the development of conservation strategies for the Turkish buffalo.

Detection of prion gene promoter and intron1 indel polymorphisms in Anatolian water buffalo (Bubalus bubalis).

Bovine spongiform encephalopathy (BSE) is a fatal disease caused by miss folded prion protein. Studies in the cattle, comparing genetic data from BSE diseased and healthy animals have shown that indel polymorphisms in the promoter and intron 1 of PRNP gene were associated with disease susceptibility. Several studies were conducted to find out allele and genotypic frequencies of indel polymorphisms in promoter and intron 1 of the cattle PRNP gene. Unlike domestic cattle and bison, no indel polymorphisms of the PRNP promoter and intron 1 were examined in any population of the water buffalo (Bubalus bubalis). Aim of this study was to analyse frequencies of allele, genotype, and haplotype of the indel polymorphisms (23 bp indel in promoter and 12 bp indel in intron 1) in prion protein coding gene (PRNP) of water buffalo. Therefore a PCR based procedure, previously used in cattle to detect indel polymorphisms of PRNP promoter and intron 1 locus, was applied to 106 Anatolian water buffalo DNAs. Our results have revealed high frequency of in variants and in23/in12 haplotype for PRNP promoter and intron 1 indel polymorphisms in water buffalo. The results of the study have demonstrated that frequencies of allele, genotype, and haplotype of the indel polymorphisms in PRNP gene of the Anatolian water buffalo are significantly different those from cattle and bison PRNP indel polymorphisms.

Applying imidacloprid via a precision banding system to control striped cucumber beetle (Coleoptera: Chrysomelidae) in cucurbits.

The striped cucumber beetle, Acalymma vittatum (F.) (Coleoptera: Chrysomelidae), is a key pest of cucurbit crops throughout its range. A novel precision band applicator was designed to inject a solid stream of imidacloprid solution in-furrow directly over the seed during planting to reduce beetle leaf feeding on pumpkin, zucchini, and cucumber crops. In 2004 and 2005, bioassays at the cotyledon through fifth leaf were conducted on striped cucumber beetles using seedling leaf tissue grown from seeds treated using both continuous and precision banded in-furrow imidacloprid solution applications. In 2004, 80% of bioassay trials had treatments with beetle mortality significantly higher than the check, whereas 70% of the bioassay trials showed no significant difference in mortality between continuous in-furrow and precision banded treatments. In 2005, 79% of bioassay trials had treatments with beetle mortality significantly higher than the check, whereas 100% of the bioassays showed no significant difference in beetle mortality between continuous in-furrow and precision banded treatments at the same insecticide rate. The environmental savings of precision banded treatments compared with continuous in-furrow treatment reduced imidacloprid up to 84.5% on a per hectare basis for all cucurbits tested in 2004 and 2005, translating into an economic savings up to $215/ha. In separate bioassay trials conducted in 2005 on pumpkin, where insecticide band length and injection volume were manipulated independently, several treatments had significantly higher beetle mortality than the check. There was a trend of increased beetle mortality in treatments using shorter band lengths combined with higher insecticide solution volumes.

Non-invasive imaging of aberrant right subclavian artery pathologies and aberrant right vertebral artery.

Here, we review the CT and MR angiography findings of aberrant right subclavian and right vertebral arteries, with emphasis on the differences between these structures. In addition, non-invasive imaging findings of aberrant right subclavian artery pathologies, including arteritis, aneurysm and dissection, are discussed.

Myocardial delayed enhancement imaging: comparison of two-dimensional and three-dimensional inversion prepared fast gradient echo and steady state free precession sequences.

We compared two-dimensional (2D) and three-dimensional (3D) inversion recovery prepared (IR) fast gradient echo (FGRE) and steady state free precession (SSFP) sequences used in myocardial delayed enhancement imaging. Twenty patients with a prior history of acute coronary syndrome were included in this study. Breath hold, ECG gated, segmented 2D and 3D IR_FGRE and SSFP sequences were acquired after intravenous administration of 0.15 mmol/kg gadodiamide-DTPA. Overall image quality, transmural extent of myocardial infarction, infarct volume, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and signal intensity ratio (SIR) were calculated and compared for each technique. 3D IR trueFISP showed significantly higher mean values of SNR and CNR compared with 3D IR turboFLASH, 2D IR turboFLASH and 2D IR trueFISP (p < 0.04 and p < 0.001). 3D IR_FGRE showed the second highest SNR and CNR. 3D IR_SSFP and 3D IR_FGRE allowed the imaging of the whole heart within a single breath-hold which reduced the imaging time significantly compared to 2D IR_FGRE and 2D IR_SSFP. 3D IR_SSFP and 3D IR_FGRE offer higher SNR, CNR and rapid acquisiton compared to 2D IR_SSFP and 2D IR_FGRE with adequate image quality.

Prevalence of extended-spectrum beta-lactamases produced by nosocomial isolates of Enterobacteriaceae in Trakya University Hospital, Turkey.

The prevalence of extended-spectrum beta-lactamase (ESBL) production by 194 nosocomial isolates of Enterobacteriacea recovered from 1995 to 1999 was investigated. The ESBL production was determined by the double-disk synergy test and was confirmed by the E-test ESBL strip. Twenty-three isolates (21 Klebsiella pneumoniae, one Escherichia coli, one Providencia rettgeri) were found as ESBL-producers (11.8%). These isolates were also usually resistant to non-betalactam antibiotics. Most of them contained a beta-lactamase with a pI of 7.6. All the strains conjugally transferred their ESBLs to recipient E. coli. Contrary to others, ESBL-producing K. pneumoniae strains isolated in 1999 were resistant to ciprofloxacin, and had the identical plasmid profiles suggestive of an outbreak. Ciprofloxacin resistance in these strains could not be transferred. In conclusion, K. pneumoniae was the main ESBL-producing species among nosocomial isolates of Enterobacteriacae in our hospital.