Health and economic outcomes of the detection of Klebsiella pneumoniae-produced extended-spectrum beta-lactamase (ESBL) in a hospital with high prevalence of this infection

Introduction: Klebsiella pneumoniae is of high prevalence in hospital infections, mainly in bloodstream infections (BSI), and some produce extended-spectrum beta-lactamase (ESBL). for hospitals with a high prevalence of strains producing this enzyme, there is no reference material to show whether the use of the E-test method for their detection, which can be quite expensive, is actually required.Objective: To evaluate the cost-benefit of the disk diffusion and E-test methods for the detection of ESBL-producing K. pneumoniae strains in hospitals where a high prevalence of this resistance mechanism in BSI is found.Methods: One hundred and eight patients with K. pneumoniae BSI were evaluated retrospectively. ESBL-producing strains were identified by the disk diffusion method and by the E-test method. We estimated the costs of both diagnostic methods based on antimicrobial therapy adequacy.Results: Fifty-two percent of K. pneumoniae infections were due to ESBL-producing strains. the disk diffusion method yielded a positive predictive value (PPV) of 94.7% (95% Cl: 88.9-100%) and a negative predictive value (NPV) of 96.1% (CI 95%: 90.8-101.4%) in relation to the E-test. We evaluated cost-effectiveness, i.e., we analyzed the cost of both E-test and disk diffusion methods with carbapenem and cephalosporins, and found that the use of the disk diffusion method accounts for approximately US$3300.Conclusions: in hospitals with a high prevalence of ESBL-producing strains, the disk diffusion method can be used to detect ESBL-producing K. pneumoniae without compromising the clinical progression of patients with BSI. the E-test showed higher accuracy but this method was more expensive than the disk diffusion method. However, the use of the E-test method was demonstrated to be more cost-effective, as we evaluated cost based on antimicrobial therapy adequacy. (C) 2005 International Society for Infectious Diseases. Published by Elsevier B.V. All rights reserved.Universidade Federal de São Paulo, Escola Paulista Med, Disciplina Doencas Infecc & Parasitarias, BR-04023062 São Paulo, BrazilUniversidade Federal de São Paulo, Escola Paulista Med, Disciplina Doencas Infecc & Parasitarias, BR-04023062 São Paulo, BrazilWeb of Scienc

The investigation of prevalence of methicillin and vancomycin resistance in coagulase negative Staphylococci isolated from clinical samples of Shahrekord university hospitals, 2009

Background: Vancomycin has been widely used in the treatment of infections caused by methicillin-resistant coagulase negative Staphylococci (MRCoNS). The emergence of vancomycin-intermediate and -resistant coagulase negative Staphylococci (VICoNS and VRCoNS, respectively) in various parts of the world, has caused great concern. In this study we investigated the prevalence of MRCoNS and Emergence of VICoNS and VRCoNS in Shahrekord Hospitals. Methods: Eighty eight coagulase negative Staphylococcus isolates were identified out of 284 Staphylococcus isolates collected from Shahrekod’s hospitals, Then, antimicrobial susceptibility pattern was determined for 12 antibiotics with Disk Diffusion method. Methicillin resistant strains were identified by several methods: Disk diffusion, E-test and Real-time PCR. Vancomycin resistant strains were also identified by several methods: Disk diffusion, Agar screening, E-test and Duplex PCR. Results: Using the disk diffusion test, 100% of isolates were resistant to penicillin while the lowest resistance (33%) was found for ofloxacin. Fourty six CoNS strains were methicillin resistant and none of these isolates were vancomycin resistant and none had vanA/vanB genes demonstrated by PCR. Conclusion: This study showed a high prevalence of MRCoNS at Shahrekord hospitals, but, vancomycin resistance was not found

Antimicrobial susceptibility testing for Helicobacter pylori isolates from Brazilian children and adolescents: comparing agar dilution, E-test, and disk diffusion

Antimicrobial susceptibility testing for Helicobacter pylori is increasingly important due to resistance to the most used antimicrobials agents. Only agar dilution method is approved by CLSI, but it is difficult to perform routinely. We evaluated the reliability of E-test and disk diffusion comparing to agar dilution method on Helicobacter pylori antimicrobial susceptibility testing. Susceptibility testing was performed for amoxicillin, clarithromycin, furazolidone, metronidazole and tetracycline using E-test, disk-diffusion and agar dilution method in 77 consecutive Helicobacter pylori strains from dyspeptic children and adolescents. Resistance rates were: amoxicillin - 10.4%, 9% and 68.8%; clarithromycin - 19.5%, 20.8%, 36.3%; metronidazole - 40.2%33.7%, 38.9%, respectively by agar dilution, E-test and disk diffusion method. Furazolidone and tetracycline showed no resistance rates. Metronidazole presented strong correlation to E-test (r = 0.7992, p < 0.0001) and disk diffusion method (r=-0.6962, p < 0.0001). Clarithromycin presented moderate correlation to E-test (r = 0.6369, p < 0.0001) and disk diffusion method (r=-0.5656, p < 0.0001). Amoxicillin presented weak correlation to E-test (r = 0.3565, p = 0.0015) and disk diffusion (r=-0.3565, p = 0.0015). Tetracycline presented weak correlation with E-test (r = 0.2346, p = 0.04) and furazolidone to disk diffusion (r=-0.0288, p = 0.8038). E-test presented better agreement with gold standard. It is an easy and reliable method for Helicobacter pylori susceptibility testing. Disk diffusion method presented high disagreement and high rates of major errors.Universidade Federal de São Paulo (UNIFESP) Escola Paulista de MedicinaUniversidade Federal de São Paulo (UNIFESP) Escola Paulista de Medicina Departamento de Doenças InfecciosasUNIFESP, EPM, Depto. de Doenças InfecciosasSciEL

rHARM: Accretion and Ejection in Resistive GR-MHD

Turbulent magnetic diffusivity plays an important role for accretion disks and the launching of disk winds. We have implemented magnetic diffusivity, respective resistivity in the general relativistic MHD code HARM. This paper describes the theoretical background of our implementation, its numerical realization, our numerical tests and preliminary applications. The test simulations of the new code rHARM are compared with an analytic solution of the diffusion equation and a classical shock tube problem. We have further investigated the evolution of the magneto-rotational instability (MRI) in tori around black holes for a range of magnetic diffusivities. We find indication for a critical magnetic diffusivity (for our setup) beyond which no MRI develops in the linear regime and for which accretion of torus material to the black hole is delayed. Preliminary simulations of magnetically diffusive thin accretion disks around Schwarzschild black holes that are threaded by a large-scale poloidal magnetic field show the launching of disk winds with mass fluxes of about 50% of the accretion rate. The disk magnetic diffusivity allows for efficient disk accretion that replenishes the mass reservoir of the inner disk area and thus allows for long-term simulations of wind launching for more than 5000 time units.Comment: 21 pages, 43 figures, accepted by Ap

Prediction of Antibiotic Influence by Presence of Some β-lactamase Gene in AcinetobacterInfected Patients Hospitalized in Tehran, Iran

Acinetobacter baumannii which is gram-negative rod and infecting hospitalized patient often develops multiple drug resistance patterns and causes serious problem in treatment. The aim of this study is to determine the relationship between this serious problem in treatment and Presence of some β-lactamase genes in the A. baumannii. 100 isolates of Acinetobacter collected from hospitalized patients in Tehran. First their resistance to different antibiotics were determined using disk agar diffusion test then the MICs of all resistant isolates determined by Etest .In the second stage we screened all resistance isolates for β-lactamase gene existence by double-disk synergy test and finally prevalence of β-lactamase encoding genes such as IMP-1,SIM-1,OXA-23,OXA-24 and OXA-58 were determined by PCR. According those tests the most efficient treatment was achieved by Colistin, Gentamicin, and Imipenem. Disk synergy test with 0.1M EDTA determined 23 % of isolates as metalo β-lactamase producers. Prevalence of β- lactamase encoding genes was: 4%, 0%, 38%, 32%, and 1% respectively. According to this study efficient treatment will be influenced by OXA β-lactamase more than the other genes which have been studied. This is the first report of SIM type among MBL-producing A. baumannii in Iran

Comparison of Real-Time PCR with Disk Diffusion, Agar Screen and E-test Methods for Detection of Methicillin-Resistant Staphylococcus aureus

Methicillin-resistant Staphylococcus aureus (MRSA) is a nosocomial pathogen. Our main objective was to compare oxacillin disk test, oxacillin E-test, and oxacillin agar screen for detection of methicillin resistance in S. aureus, using real-time PCR for mecA as the ``gold standard'' comparison assay. 196 S. aureus isolates were identified out of 284 Staphylococcus isolates. These isolates were screened for MRSA with several methods: disk diffusion, agar screen (6.0 mu g/ml), oxacillin E-test, and real-time PCR for detection of mecA gene. Of the 196 S. aureus isolates tested, 96 isolates (49%) were mecA-positive and 100 isolates (51%) mecA-negative. All methods tested had a statistically significant agreement with real-time PCR. E-test was 100% sensitive and specific for mecA presence. The sensitivity and specificity of oxacillin agar screen method were 98 and 99%, respectively and sensitivity and specificity of oxacillin disk diffusion method were 95 and 93%, respectively. In the present study, oxacillin E-test is proposed as the best phenotypic method. For economic reasons, the oxacillin agar screen method (6.0 mu g/ml), which is suitable for the detection of MRSA, is recommended due to its accuracy and low cost

Capsular serotype and antibiotic resistance of group B streptococci isolated from pregnant women in Ardabil, Iran

Background and Objectives: Group B Streptococci (GBS) is a major cause of neonatal and maternal infections. The aim of this study was to determine the serotype distribution and antibiotic resistance profile of GBS strains isolated from pregnant women in Ardabil. Materials and Methods: Antibiotic resistance of 56 GBS isolates was investigated using E-test strips and disk-diffusion method. Serotyping was performed using capsular antiserum. Results: The results of MIC tests showed all isolates were susceptible to ampicillin, vancomycin and penicillin. One isolate (1.7%) showed reduced susceptibility pattern to penicillin (MIC; 0.25 μg/ml). There were 3 (5.3%) isolates semi-sensitive (0.25-1 μg/ml) to erythromycin (2; 0.5 μg/ml and 1; 0.38 μg/ml) and 2 (3.5%) isolates to clindamycin (1; 0.5 μg/ml, 1; 0.38 μg/ml). Additionally, 2 (3.5%) isolates were resistant to clindamycin (1; 16 μg/ml, 1; 2 μg/ml). According to the disk diffusion test, 47 (83.9%), 8 (14.2%) and 7 (12.5%) isolates were resistant to Co-trimoxazole, ciprofloxacin and ceftriaxone respectively. Serotypes V (19.6%), II (12.5%) and IV (12.5%) were the most frequent followed by serotypes III (10.7%) and VI (10.7%), Ib (8.9%), Ia (7/1%), VII (5/3%) and VIII (5/3%); 7.1% of strains were nontypeable. Conclusions: In this study, most isolates were sensitive to common antibiotics, but increased resistance to other antibiotics indicates the importance of monitoring of antibiotic resistance in group B streptococci over time

Comparison of the performance of Disk diffusion, Agar screening and E-test methods with Real- time PCR for the detection of methicillin resistant coagulase negative Staphylococcus strains isolated from clinical samples of Shahrekord university hospitals, 2008

Background : Coagulase Negative staphylococci (CoNS) are nosocomial pathogens. The main objective of the study was to compare the performance of disk diffusion, E-test and agar screening methods with Real-time PCR technique for detection of methicillin resistance in coagulase negative staphylococci (MRCoNS), using Taqman® Real-time PCR for mecA DV WKH ³ JROG VWDQ GDUG´ FRP SDULVRQ DVVD\ � Methods : 88 coagulase negative Staphylococcus isolates were identified out of 284 Staphylococcus isolates collected from Hajar and Kashani hospitals-shahrekod, Iran. Methicillin resistance strains were identified by several methods: Disk diffusion, Agar screening, E-test and Real-time PCR. The results of the tested methods ZHUH FRP SDUHG ZLWK WKRVH RI WKH 5 HDO� WLP H 3& 5 E\ & KL VTX DUH RU ) LVKHU¶ V H[ DFW WHVWV� Results : Of the 88 coagulase negative Staphylococcus isolates tested, 46 isolates (52.3%) were mecA - positive and 42 isolates (47.7%) were mecA-negative. The results of all the tested methods had a statistically significant agreement with those of Real-time PCR. The E-test was 100% sensitive and specific for mecA presence. The sensitivity and specificity of oxacillin agar screen (6.0 µg/ml) method were 96% and 98%, respectively and the sensitivity and specificity of oxacillin Disk diffusion method were 91% and 90%, respectively. Conclusion: In the present study, E-test is proposed as the best phenotypic method. In case economic issue matters, the oxacillin agar screening method (6.0 µg/ml), which is suitable for the detection of MRCoNS due to its accuracy and low cost, is recommended. Keywords : methicill

Uji Efektivitas Antibakteri Ekstrak Etanol Dan Ekstrak Air Kelopak Bunga Rosella (Hibiscus Sabdariffa L.) Terhadap Bakteri Streptococcus Pneumoniae* [the Effectiveness Test of Antibactery of Rosella (Hibiscus Sabdariffa L.) Sheath Ethanol Extract and Wate

The in vitro study of antibacterial effectiveness of Rosella (Hibiscus sabdariffa L.) sheath ethanol extract and water extract on Streptococcus pneumoniae was conducted by diffusion and dilution method. Basic solution amounting to 70g/100 ml of the extract was diluted into 10%, 30%, 50% and 70% for diffusion test with positive control ampicillin 10 IU, and 0,1%, 0,25%, 0,5%, 1%, and 2% ethanol extract for dilution test on S. pneumoniae. The results showed that the ethanol extract and water extract could delay of bacterium growth. Agar diffusion test (disk diffusion) was observed by diameter of bar region around the disk. At concentration 70 % among extract ethanol and water extract made bar zone wide the best, the diameter mean was estimated 25.6 mm for ethanol extract, and 24.3 mm for water extract on S. pneumoniae. In dilution test, the result showed Minimum Inhibitory Concentration (MIC) of the extract was 1% on S. pneumoniae. The result of phytochemicals test is known that ethanol extract and water extract of rosella contains of saponin, tanin, and flavonoid