Risk factors of carbapenem-resistant Klebsiella pneumoniae infection in ICU patients and construction of a prediction model for infection / 中华临床感染病杂志

Objective:To analyze the risk factors of carbapenem-resistant Klebsiella pneumoniae (CRKP) infection in intensive care unit (ICU) patients and to construct a prediction model for infection. Methods:The clinical data of 204 patients with Klebsiella pneumoniae infection admitted in ICU of Jining First Hospital during January 2020 to December 2022 were retrospectively analyzed. Patients admitted during January 2020 to December 2021 were selected as model set ( n=150), and patients admitted during January to December 2022 were selected as validation set ( n=54). In model set, there were 59 cases infected with CRKP (CRKP group) and 91 cases infected with carbapenem-sensitive Klebsiella pneumonia (CSKP group). The risk factor of CRKP infection in ICU patients were analyzed with multivariate Logistic regression, based on which an infection prediction model was constructed. The predictive value of the model was evaluated by ROC, and verified in the validation group. Results:Multivariate Logistic regression analysis showed that empirical use of beta-lactam antibiotics( OR=6.985, 95 % CI 1.658-29.423, P=0.008), central vein catheterization( OR=7.486, 95 % CI 2.776-20.186, P<0.001)and tracheal intubation/incision( OR=10.695, 95 % CI 2.701-42.351, P=0.001)were risk factors for CRKP infection in ICU patients. The regression equation for predicting the risk of infection was -4.851+ empirical use of beta-lactam antibiotics×1.944+ central vein catheterization×2.013+ tracheal intubation/incision×2.370. The area under the ROC curve (AUC) of the model for predicting infection in the model group was 0.905, with sensitivity and specificity of 79.7% and 90.1%, respectively. The AUC of the model for predicting infection in validation group was 0.881, with sensitivity and specificity of 84.2% and 85.7%, respectively. Conclusion:The constructed infection prediction model in the study can effectively predict CRKP infection in ICU patients.

Progress on the mechanism of resistance of Streptococcus pneumoniae to β-lactam antibiotics and vaccine immunoprophylaxis / 国际儿科学杂志

Streptococcus pneumoniae(SP)is one of the common pathogens of respiratory tract infection in children, which can evolve into severe pneumonia and necrotizing pneumonia in case of severe infection.β-lactam antibiotics are the first-line treatment for SP.The resistance mechanism of SP to β-lactam antibiotics is mainly PBPs gene mutation, followed by mutations related to non-PBPs genes such as MurM, CpoA, TEM, CiaH/CiaR-TCSS and StkP-PhpP signal conjugations.Antibiotic selection pressure and vaccine-induced serotype substitution may influence SP resistance.Serotypes 19F and 19A have high resistance to β-lactam antibiotics, and promotion of PCV13 may be more beneficial than other SP vaccines in preventing SP infection in children.

In-vitro activity of β-lactams/trimethoprim-sulfamethoxazole combinations against different strains of Burkholderia pseudomallei

@#Trimethoprim-sulfamethoxazole is an active agent against Burkholderia pseudomallei and is being used in intensive and maintenance phases of melioidosis therapy. In this study, we evaluated the bactericidal activities of β-lactams (imipenem, ceftazidime and amoxicillinclavulanate) alone and in combinations with trimethoprim-sulfamethoxazole against B. pseudomallei. Four clinical strains of B. pseudomallei were selected based on different genotypes that are frequently found in Malaysia. The minimum inhibitory concentrations of trimethoprim-sulfamethoxazole, ceftazidime, imipenem and amoxicillin-clavulanate were determined using microdilution broth method. The bactericidal activities and synergy effects of β-lactams and/or trimethoprim-sulfamethoxazole were evaluated by checkerboard and static time-kill analyses at 1×MIC concentration of each antibiotic. Using checkerboard method, the β-lactam/trimethoprim-sulfamethoxazole combinations exhibited ΣFIC of 0.75-4.00. In time-kill analysis, ceftazidime/trimethoprim-sulfamethoxazole combination demonstrated synergy against three strains (less 2.25-2.41 log10CFU/mL compared to the most active antibiotic monotherapy) whereas imipenem/trimethoprim-sulfamethoxazole combination regimen showed synergy against one strain (less 3.32 log10CFU/mL). No antagonist effect or major re-growth was observed in all combination regimens, whereas 11 out of 12 of β-lactam monotherapy regimens were associated with re-growth of bacteria. However, all β-lactam monotherapy regimens exhibited rapid and stronger killing activities against BUPS/07/14, in the initial 12 hours compared to β-lactam/ trimethoprimsulfamethoxazole combination regimens. The combination of β-lactams with trimethoprimsulfamethoxazole demonstrated better killing effect at 24 hours compared to monotherapy and no major bacterial regrowth was observed. Nevertheless, delay in killing activities of β-lactam/trimethoprim-sulfamethoxazole combination regimens against BUPS/07/14 need further examination because this phenomenon can lead to treatment failure in some patients.

β-Lactam antibiotics promoting aging and clearance of RBCs would deteriorate the DIIHA / 中国输血杂志

【Objective】 To analyze the influence of β-lactam antibiotics on RBC aging and clearance by detecting various indicators of aging and clearance on RBCs, as well as the differences in phagocytosis for erythrocytes before and after drugs treated in vitro. 【Methods】 RBCs were treated by β-lactam antibiotics, including Penicillin, Cefepime, Cefoperazone and Ceftazidime, and the changing of phosphatidylserine (PS) and clearance related CD markers, including CD35, CD47, CD55 and CD59 on the surface of the RBCs, were detected by flow cytometry at 0h and 24h after drugs treatment. The proportion of acanthocytes by microscope also at 0h and 24h after drugs treatment was calculated. The phagocytosis of drug-treated RBC was detected by monocyte monolayer assay (MMA). Untreated RBCs were incubated in PBS by the same condition as a negative control.The influence of β-lactam antibiotics on RBC aging and clearance by all the results above was studied. 【Results】 Compare to the untreated RBCs, the drug treated RBCs showed a higher PS level on the cell surface. The results showed by percentage as following(0 h vs 24 h): Penicillin 9.42% vs 93.30%, Cefepime 3.88% vs 57.27%, Cefoperazone 4.71% vs 75.75% and Ceftazidime 3.05% vs 43.19%. The acanthocytes ratio was as following(0 h vs 24 h): Penicillin 7.33% vs 86%, Cefepime 2.67% vs 52.67%, Cefoperazone 3.33% vs 67.67% and Ceftazidime 3.33% vs 90.67%. On the opposite, the clearance related CD markers, showed an obviously lower level after drugs treated(0 h vs 24 h): CD35: Penicillin 7.36% vs 11.87%, Cefepime 0.14% vs 28.51%, Cefoperazone 11.85% vs 21.55% and Ceftazidime 7.63% vs 8.73%; CD47: Penicillin 1.22% vs 9.13%, Cefepime 1.80% vs 0.86%, Cefoperazone 0.08% vs 6.85% and Ceftazidime 1.54% vs 5.50%; CD55: Penicillin 14.46% vs 44.31%, Cefepime 17.27% vs 38.41%, Cefoperazone 19.28% vs 33.28% and Ceftazidime 14.62% vs 34.13%; CD59: Penicillin 4.71% vs 20.56%, Cefepime 4.03% vs 7.60%, Cefoperazone 5.91% vs 22.38% and Ceftazidime 5.93% vs 30.89%. Drug-treated RBCs attached more to monocytes than untreated RBCs. 【Conclusion】 The β-lactam antibiotics could induce the changing of PS and the clearance of related CD markers on surface of RBCs. They also could lead acanthocytes and make the RBCs more susceptible to phagocytosis by monocytes. The β-lactam antibiotics could promote the RBCs aging and clearance, which might deteriorate the DIIHA.

β-lactam antibiotic binding sites in Streptococcus pneumoniae StkP kinase extracellular region / 中华微生物学和免疫学杂志

Objective:To analyze the binding ability of motifs in the serine/threonine kinase StkP extracellular region (EC-StkP) of Streptococcus pneumoniae to β-lactam antibiotics. Methods:Three motifs (SXXK) in the EC-StkP were mutated into AXXA, respectively or simultaneously. Four mutant plasmids (EC- stkp-AXXA1, EC- stkp-AXXA2, EC- stkp-AXXA3 and EC- stkp-AXXA4) were transfected into recipient cells for cloning and expression. SDS-PAGE combined with gel image analysis was used to detect the expression of the recombinant mutant proteins (EC-rStkP-AXXA1, EC-rStkP-AXXA2, EC-rStkP-AXXA3 and EC-rStkP-AXXA4). The expressed mutated proteins were extracted and purified by Ni-NTA affinity chromatography. The binding abilities of the mutant proteins to penicillin (PCN) and cefotaxime (CTX) were detected by isothermal titration calorimetry (ITC 200) and surface plasmon resonance (Biacore t200). Results:PCN and CTX could not bind to the expressed proteins with mutations in the first or the third motif (EC-rStkP-AXXA1, EC-rStkP-AXXA3, EC-rStkP-AXXA4). EC-rStkP-AXXA2 could weakly bind to CTX, but not to PCN.Conclusions:All three motifs in the EC-StkP of Streptococcus pneumoniae could bind to β-lactam antibiotics with the first and the third motifs being more important.

Sensibilidad disminuida a los antibóticos Beta-Lactamicos en estreptococos Beta-Hemolíticos / Decreased sensitivity to beta-lactam antibiotics in beta-hemolytic streptococci

Últimamente, se están detectando mutaciones en las proteínas ligadoras de penicilina (PBP) de los estreptococos beta-hemolíticos que corresponden a sitios que en Streptococcus pneumoniae han determinado sensibilidad disminuida a los antibióticos beta-lactámicos. Primero, se describieron cepas con sensibilidad intermedia a penicilina en Streptococcus agalactiae (estreptococos del grupo B), luego en Streptococcus dysgalactiae subsp. equisimilis (mayormente grupos C y G) y, más recientemente, cepas con sensibilidad disminuida a aminopenicilinas y cefalosporinas de tercera generación en Streptococcus pyogenes (grupo A). El costo biológico de estas modificaciones nos permite pensar que los niveles de resistencia no han de ser tan elevados como para comprometer por ahora la efectividad clínica de los beta-lactámicos (AU)

Recently, mutations in penicillin-binding proteins (PBPs) of beta-hemolytic streptococci have been detected corresponding to sites that in Streptococcus pneumoniae have been determined to have decreased sensitivity to beta-lactam antibiotics. First, strains with intermediate sensitivity to penicillin were described in Streptococcus agalactiae (group B streptococci), subsequently in Streptococcus dysgalactiae subsp. equisimilis (mainly groups C and G) and, more recently, strains with decreased sensitivity to third-generation aminopenicillins and cephalosporins were found in Streptococcus pyogenes (group A). The biological cost of these modifications suggests that, for now, resistance levels are not high enough to compromise the clinical effectiveness of beta-lactams (AU)

β-lactam antibiotics detection using microcolumn gel technology / 中国输血杂志

【Objective】 To develop an assay to determine β-lactam antibiotics using microcolumn gels and to study the β-lactam antibiotics present in the blood of patients and their clinical significances. 【Methods】 446 patients with a history of taking β-lactam antibiotics from January 2019 to June 2019 were randomly selected from Trauma Emergency Center, Department of Arthrosis, Department of Spine and Department of Bone Oncology of our hospital, and 4 mL(per capita) venous blood was collected. Irregular antibody screening, anti-globulin detection and drug antibody determination were performed by microcolumn gel method. The data of gender, age, disease, blood transfusion history and medication were collected. The test results and clinical data were retrospective analyzed. 【Results】 The yielding rate of antibody was 0.45%(2/446) in patients with a history of taking β -lactam antibiotics. 16.38%(73/446) of the samples were positive in direct antiglobulin test, and 64.38%(47/73) of them did not agglutinate with RBCs treated with drugs. The yielding rate of specific antibodies against drug was 4.93%(22/446), and the titer ranged from 2 to 128(8). 1 case of auto-IgM antibody, 1 case of blood group related antibody and 2 cases of non-specific protein adsorption were detected. The yielding rate of drug antibody in patients with blood transfusion history reached to 12.10 %(22/124), so it was also high in patients with bone tumor. 【Conclusion】 Direct antiglobulin assay is helpful for the detection of β-lactam antibodies. The negative results of antibody screening cannot completely exclude the presence of drug antibodies. The yielding rate of drug antibody can be greatly improved by specific drug antibody detection, and it was higher in transfused patients relative to non-transfused one.

Escherichia coli y Klebsiella pneumoniae productoras de betalactamasas de espectro extendido en un hospital de La Habana

RESUMEN Introducción: En microorganismos gramnegativos la producción de enzimas betalactamasas es el mecanismo más común de resistencia. Las de espectro extendido constituyen un grupo importante por su capacidad de inactivar las cefalosporinas de tercera y cuarta generación y el aztreonam. Su detección es vital para indicar el tratamiento óptimo y las medidas de aislamiento que eviten la dispersión de los microorganismos que las portan. Objetivos: Determinar la incidencia y principales características de los aislados de Escherichiacoli y Klebsiellapneumoniae productores de betalactamasas de espectro extendido en muestras no urogenitales. Métodos: Estudio transversal realizado en el hospital "Salvador Allende" durante el año 2017. Se determinó la frecuencia de Escherichia coli y Klebsiella pneumoniae productoras de betalactamasas de espectro extendido, su procedencia según servicio del hospital, tipo de muestra clínica, y su sensibilidad antimicrobiana. La identificación de betalactamasas de espectro extendido se hizo por el método de doble disco de Jarlier. Resultados: Fueron productores de betalactamasas de espectro extendido 46 y 50 % de aislados de Escherichia coli y Klebsiella pneumoniae, respectivamente. La mayoría provenían de muestras de las salas del Instituto de Angiología, el antimicrobiano con mayor efectividad fue el meropenem, la sensibilidad al resto de los antimicrobianos estuvo por debajo de 80 % y no hubo aislados sensibles a las cefalosporinas de tercera generación. Conclusiones: Se demuestra una alta incidencia de aislados de Escherichia coli y Klebsiella pneumoniae productores de betalactamasas de espectro extendido en el Hospital "Salvador Allende" de La Habana, más marcada en las salas del Instituto de Angiología y en muestras de piel.

ABSTRACT Introduction: Beta-lactamase production is the most common resistance mechanism in gram-negative microorganisms. Extended-spectrum beta-lactamases are an important group of enzymes capable of inactivating third- and fourth-generation cephalosporins and aztreonam. Their detection is important to indicate the optimum treatment as well as isolation measures aimed at preventing the spread of carrier microorganisms. Objectives: Determine the incidence and main characteristics of isolates of extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella pneumoniae from non-urogenital samples. Methods: A cross-sectional study was conducted at Salvador Allende hospital during the year 2017. Determination was made of the frequency of extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella pneumoniae, their origin by hospital service, the type of clinical sample and their antimicrobial sensitivity. Identification of extended-spectrum beta-lactamases was based on the Jarlier double disc method. Results: Of the total Escherichia coli and Klebsiella pneumoniae isolates studied, 46% and 50%, respectively, were extended-spectrum beta-lactamase producers. Most had been obtained from samples taken in wards of the Institute of Angiology; the most effective antimicrobial was meropenem; sensitivity to the remaining antimicrobials was below 80%; no isolates were sensitive to third-generation cephalosporins. Conclusions: A high incidence was found of extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella pneumoniae isolates at Salvador Allende Hospital in Havana, more noticeably in Institute of Angiology wards and skin samples.

Analysis of polymer impurities in ceftazidime raw materials and preparations / 药学学报

To establish a method for the determination of polymer impurities in ceftazidime raw materials and preparations, a ceftazidime degradation solution containing polymer impurities was prepared by forced polymerization. Polymer impurities in the degradation solution were separated and identified by high performance gel chromatography and the column switching-LC-MSn method. A new RP-HPLC method for ceftazidime polymer was established and validated with a Phenomenex Gemini-C18 column using a mobile phase gradient elution of 0.02 mol·L-1 phosphate buffer, methanol and acetonitrile. The results showed that when using this high performance gel chromatography method some small molecular weight impurities were co-eluted with the polymers, resulting in a poor specificity and poor quantitative accuracy. But when using the RP-HPLC method, four polymer impurities were detected in the 25-45 min time range with good specificity, sensitivity and robustness, including two ceftazidime dimers, trimers, and derivatives. Therefore, the described RP-HPLC method is suitable for the quality control of polymer impurities in ceftazidime, and ceftazidime degradation solution can be used as suitable solution for analysis of ceftazidime polymers.

Analysis of polymer impurities in cefixime raw materials and preparations / 药学学报

To establish a method for the determination of polymer impurities in cefixime raw materials and preparations, a cefixime degradation solution containing polymer impurities was prepared by forced polymerization. Polymer impurities in the degradation solution were separated and identified by high performance gel chromatography and the column switching-LC-MSn method. A new RP-HPLC method for cefixime polymer was established and validated with a Phenomenex Gemini-C18 column using a mobile phase gradient elution of 0.5% formic acid-water solution and 0.5% formic acid-acetonitrile solution. The results showed that when using this high performance gel chromatography method some small molecular weight impurities were co-eluted with the polymers, resulting in a poor specificity and poor quantitative accuracy. But when using the RP-HPLC method, three polymer impurities were detected with good specificity, sensitivity and robustness, including two cefixime dimers, and dehydrate dimer. Therefore, the described RP-HPLC method is suitable for the quality control of polymer impurities in cefixime, and cefixime degradation solution can be used as suitable solution for analysis of cefixime polymers.

Screening and quantification of 16 β-lactam antibiotics in pork by UPLC-Q-Orbitrap / 预防医学

Objective@#To screen and quantify 16 kinds of β-lactam antibiotics in pork by high performance liquid chromatography-quadrupole/electrostatic field orbit trap mass spectrometry（UPLC-Q-Orbitrap）.@*Methods@#The pork samples were extracted by ultrasound with acetonitrile，then the supernatant was centrifuged and purified by HLB solid phase extraction column. The analytes were separated by Waters HSS T3 column（100 mm×2.1 mm，1.8 μm）with gradient elution. Mass spectrometry adopted positive ion scanning and targeted SIM/dd-MS2 monitoring mode to complete the separation of analytes in samples and mass spectrometry analysis within 10 minutes. The chromatographic retention time and fragments in mass spectrometry were compared with prepared standards to determine whether the samples contained the antibiotics tested，then the positive samples were quantified.@*Results@#The 16 kinds of β-lactam antibiotics had good linear relationship in the range of 5-400 ng/mL（all the correlation coefficients >0.99）. The detection limits ranged from 0.08 μg/kg to 0.41 μg/kg，recovery rate ranged from 85.5% to 116.7%，and relative standard deviation（RSD）ranged from 3.6% to 12.8%. One of twenty pork samples detected was found penicillin G（28 μg/kg）and ampicillin（18.5 μg/kg）.@*Conclusion@#UPLC-Q-Orbitrap has high resolution and can reduce matrix interference to improve the accuracy. This method is simple，fast and efficient，thus can be used to screen and quantify β-lactam antibiotics in pork.

Prevalencia de Escherichia coli, productora de BLEE en pacientes ambulatorios de la ciudad de Cuenca / Prevalence of Escherichia coli, ESBL producer in outpatients of the city of Cuenca

Se analizó un total de 274 muestras de orina de pacientes ambulatorios que acudieron a los centros de salud 1, 2 y 3 de la ciudad de Cuenca durante el periodo comprendido entre mayo y junio del año 2013, con el fin de obtener al menos 100 muestras de orina con presencia de Escherichia coli. Se recuperaron 103 cepas de Escherichia coli y se continuó el estudio con la identificación de la producción de Betalactamasas de Espectro Extendido (BLEE), mediante la técnica descrita en el manual CLSI. Se realizaron las pruebas presuntivas y confirmatorias, aplicando el método convencional de difusión en agar, en placas de agar Mueller-Hinton, con un inóculo Mac Farland 0,5 y ensayando los discos de antimicrobiano. Para la prueba presuntiva se emplearon los discos de aztreonam, cefotaxime, ceftazidime y ceftriaxona; para la prueba confirmatoria se utilizaron los discos de ceftazidime y cefotaxime en combinación con ácido clavulánico; la producción de BLEE se determinó mediante la diferencia del diámetro de los halos según se indica en la técnica. Los resultados mostraron que de 103 cepas de E. coli se recuperaron siete (6,8 %) cepas productoras de BLEE y si se considera que la población con la que se trabajó fue de pacientes ambulatorios resulta muy importante la realización de los métodos de identificación de BLEE como apoyo para la correcta terapia antimicrobiana, previniendo de esta manera la diseminación de cepas de E. coli productoras de BLEE.

A total of 274 urine samples were analyzed from outpatients presenting to Health Centers 1, 2 and 3 of the city of Cuenca during the period between May and June 2013, with the purpose to get at least 100 samples positive urine with Escherichia coli. Were retrieved 103 strains of Escherichia coli and the study was continued with the identification of the production of Extended Spectrum Beta Lactamases (ESBL), using the technique described in the CLSI manual. Were performed presumptive and confirmatory tests, applying the conventional method of agar diffusion plates in Mueller-Hinton agar, with a 0.5 McFarland inoculum and tested antimicrobial discs. For the presumptive test was used discs aztreonam, cefotaxime, ceftazidime and ceftriaxone, for the confirmatory test were used discs of ceftazidime and cefotaxime in combination with clavulanic acid. ESBL production was determined by the difference in the diameter of the halos as indicated in the technique. The results showed that of 103 strains of E. coli recovered seven (6,8 %) ESBL producing strains, when considering that the population which was worked was of outpatient, is very important the implementation of identification methods as ESBL for correct support of antimicrobial therapy, preventing this way the spread of strains of E. coli ESBL producing.

Sensibilización a los alérgenos de las penicilinas en pacientes que padecen enfermedades alérgicas / Sensitization to penicillin allergens in patients suffering from allergic diseases

Los antibióticos ß-lactámicos son los más utilizados, dada su eficacia para patógenos bacterianos comunes y su precio relativamente bajo. Para evaluar la sensibilización a los alérgenos mayores y menores de la penicilina en pacientes que padecen enfermedades alérgicas, se realizó un estudio observacional analítico de casos y controles, en el universo de 458 individuos derivados al Servicio de Alergia Previsora (Camagüey, Cuba), desde enero del 2010 hasta noviembre del 2016. Se seleccionó una muestra de 178 niños y adultos con el diagnóstico de asma, rinitis y urticaria de las edades 6 a 60 años. Los que tenían antecedentes, no confirmados, de alergia a penicilinas se consideraron casos (n=60) y los que no tenían el antecedente controles (n=118). Toda la muestra tenía pruebas de Prick positivas a uno o más de los ácaros domésticos Dermatophagoides pteronysinus, Dermatophagoides siboney y Blomia tropicalis, así como a algún alimento. Un grupo de ellos también resultaron positivos a PPL y MD. Se distribuyeron los pacientes en sensibilizados o no con los alérgenos PPL y MD. La prevalencia general de alergia a las penicilinas fue de 24,15 por ciento (15,7 por ciento en los casos y 8,9 por ciento en los controles). La prueba DAP® - Penicilinas mostró mayor número de positivos en los casos que en los controles (p=0,037, OR=5,21). Del total de alérgicos a las penicilinas, el mayor número de pacientes correspondieron al sexo femenino (p=0,031). El test cutáneo con alérgenos PPL y MD puede confirmar el diagnóstico de alergia a penicilinas en pacientes atópicos(AU)

ß-lactam antibiotics are the most widely used, given their efficacy for common bacterial pathogens and their relatively low price. To evaluate sensitization to major and minor allergens of penicillin in patients suffering from allergic diseases, an observational, analytical study of cases and controls was carried out in the universe of 458 individuals referred to the Previsora Allergy Service (Camagüey, Cuba) from January 2010 to November 2016. A sample of 178 children and adults aged 6 to 60 years diagnosed with asthma, rhinitis and urticarial was selected. Those who had a medical history, not confirmed, of allergy to penicillins were considered cases (n=60) and those who did not have the antecedent were the controls (n=118). All the sample had positive Prick tests to one or more of the house mites Dermatophagoides pteronysinus, Dermatophagoides siboney and Blomia tropicalis, as well as against some foods. Some individuals were also positive for PPL and MD. Patients were distributed in sensitized or not with the allergens PPL and MD. The general prevalence of allergy to penicillins was 24.15 percent (15.7 percent in cases and 8.9 percent in controls). The DAP® - Penicillins test showed a greater number of positives in cases than in controls (p=0.037; OR=5.21). The largest number of patients allergic to penicillins corresponded to the female sex (p=0.031). The skin test with allergens PPL and MD can confirm the diagnosis of allergy to penicillins in atopic patients(AU)

Progress in regulatory mechanism for inducing β-lactamase in Gram-negative bacteria / 生物工程学报

Beta-lactams are the most widely used antibiotics. One of the principle mechanisms for Gram-negative bacteria to resist β-lactams is by producing β-lactamases that degrade β-lactams. This review highlights two regulatory mechanisms for inducing β-lactamase in Gram-negative bacteria. In the ampR-ampC paradigm, the induction of β-lactamase is intimately linked to peptidoglycan recycling. AmpR, a LysR-type transcriptional regulator, plays a central role in regulating expression of β-lactamase. Recent studies found that two-component signal transduction pathway is activated by β-lactams, which in turn induces the expression of β-lactamase. Finally, we discussed the future research directions in β-lactam resistance in Gram-negative bacteria.

Mechanism of Clinical Cross Allergy Reaction of β-lactam Antibiotics and Introduction of Related Treat-ment Processes in USA / 中国药房

OBJECTIVE:To investigate the mechanism of cross allergy reaction during the application of β-lactam antibiotics, and to provide reference for rational drug use in clinic. METHODS:Based on study experience of author in UIC and its affiliated hospital during advanced study,according to the experience of drug use safety management in patients allergic to β-lactam antibiot-ics from Rush University Medical Center,the mechanism of cross allergy reaction during the application of β-lactam antibiotics was summarized,and the disposal procedure for patients allergic to β-lactam antibiotics in the Affiliated Hospital of UIC was intro-duced. RESULTS:The principal reason for cross allergy reaction induced by β-lactam antibiotics were same or similar side chains between drugs. Cross allergy reaction occurred when IgE recognized these side chains. The disposal procedure for patients allergic to β-lactam antibiotics in the Affiliated Hospital of UIC included that the indication of β-lactam use was evaluated;standard penicil-lin skin testing according to evaluation results,anti-infection treatment by Grade challenge β-lactam antibiotics and course and rap-id drug tolerance induction. CONCLUSIONS:The disposal method for patients allergic to β-lactam antibiotics in the Affiliated Hos-pital of UIC can provide new thought for domestic clinical pharmacists in rational drug use among the patiens with reported aller-gies to special group as pregnant women,children.

Streptococcus pneumoniae StkP kinase: binding ability with β-lactam antibiotics and correlation with drug resistance / 中华微生物学和免疫学杂志

Objective To investigate the correlation between Streptococcus pneumoniae (S.pneumoniae) StkP kinase and drug resistance and to analyze the binding ability of StkP extracellular region (EC-StkP) to β-lactam antibiotics.Methods A stkP gene knockout (ΔstkP) mutant was constructed from S.pneumoniae strain ATCC6306 by insertional inactivation method.E-test was performed to detect the minimum inhibitory concentrations (MIC) of penicillin (PCN) and cefotaxime (CTX) against ΔstkP mutant and its wild-type strain.Bioinformatic softwares were used to predict the EC-StkP of S.pneumonia strain ATCC6306,to generate the three-dimensional structure model of EC-StkP and to analyze the correlation between the structure and functions of EC-StkP.PCR was performed to amplify the extracellular segment of stkP (EC-stkP) gene and the product of it was sequenced after T-A cloning.A prokaryotic expression system of EC-stkP gene was constructed.SDS-PAGE in combination with a gel image analysis system was used to detect the expression of the recombinant EC-StkP (EC-rStkP).The expressed EC-rStkP was extracted by Ni-NTA affinity chromatography.The binding abilities of EC-rStkP to PCN and CTX were detected by isothermal titration calorimetry (VT-ITC) and surface plasmon resonance (Biacore).Results S.pneumonia strain ATCC6306 was sensitive to PCN (MIC=0.06 μg/ml) and CTX (MIC=0.12 μg/ml),but its ΔstkP mutant was resistant to the two antibiotics (PCN MIC=16 μg/ml,CTX MIC=32 μg/ml).The 295 aa segment was predicted as the extracellular region at C-end of StkP of S.pneumoniae strain ATCC6306,containing four penicillin-binding proteins and Ser/Thr kinase-associated (PASTA) domains.The cloned EC-stkP segment and the EC-stkP segment in GenBank shared 99.6% similarity in nucleotide sequence and 100% in amino acid sequence.The constructed prokaryotic expression system for EC-stkP gene expressed EC-rStkP in soluble form.Both PCN and CTX could bind to EC-rStkP and CTX was better than PCN in term of binding ability.Conclusion The stkP gene of S.pneumonia is closely related to drug resistance and the encoded protein,Ser/Thr kinase StkP,can recognize and bind to β-lactam antibiotics.

Mechanism of Coriaria sinica extract on anti-methicillin resistant Staphylococcus aureus / 中草药

Objective: To explore the synergies mechanism of Coriaria sinica extract (CSE) combined with β-lactam antibiotics on methicillin resistant Staphylococcus aureus (MRSA). Methods: The relevant gene expression, autolytic enzyme, and influence of β-lactamase were determined by AFFX prokaryotic expression microarray, Western-blotting, SDS-PAGE gel electrophoresis, etc. Results: MRSA was resistant to the most antibiotics, and it had significant synergistic antibacterial effect while CSE was combined with β-lactam antibiotics (P < 0.05). The CSE can significantly reduce the total expression of RNA and regulate the expression of many genes with showing a dose-dependence when used alone or combined with ampicillin (AP), such as the basal metabolism genes, peptidoglycan hydrolase gene (lytM), transporter gene, PBPs, β-lactamase activity, etc. (P < 0.05). It can significantly improve the concentration of cefotaxime (CFX) in internal of MRSA (P < 0.05). Conclusion: The CSE has significant inhibitory effects on MRSA, and it has significant synergistic effects when combined with β-lactam antibiotic on MRSA. The mechanism is associated with many factors of MRSA, such as regulation of expression and transcription on target genes (ribA, PBPs, lytM, etc.), the influence of active efflux, autolysis and metabolism, etc.

Actividad comparativa in vitro de doripenem y otros carbapenemicos frente a pseudomonas aeruginosa aisladas en el laboratorio de microbiología del hospital Vargas de Caracas / Comparative in vitro activity of dorypenem and other carbapenems in pseudomonas aeruginosa isolates on Vargas Caracas Hospital´s Microbiology

Los ensayos de cuantificación de ARN plasmáticos de VIH-1 son importantes para el control de pacientes infectados, así como el monitoreo de la respuesta a la terapia antirretroviral. Por lo tanto, los ensayos comerciales empleados para este propósito deben presentar buena correlación entre si, para dar lugar al manejo terapéutico apropiado. El objetivo del estudio consistió en correlacionar los resultados obtenidos mediante el ensayo de amplificación de señal (bDNA) y PCR en tiempo real (RT-PCR), ambas casas comerciales aprobadas por la FDA y con diferente diana de detección del VIH-1. La validación se realizó con 180 muestras clínicas de pacientes referidos al INHRR. Los resultados fueron comparados con la subpoblación de linfocitos TCD4+ determinados mediante citometría de flujo. El análisis estadístico se realizó empleando el coeficiente de regresión lineal de Pearson (R2) y el valor de contraste de hipótesis con una significancia del 95 %, usando el programa SPSS Statistics v10.0. Se observó una buena correlación entre los ensayos (R2=0.961, p<0.05), siendo la RTPCR más sensible. Las diferencias cuantitativas de carga viral entre las técnicas ensayadas fue menor de 0.5 log10 copias/ml para el 89% de las muestras, y >1 log10 copias/ml solo en dos pacientes, no indicando necesariamente cambio terapéutico. Adicionalmente, se encontró una correlación inversa entre los linfocitos TCD4+ y carga viral del VIH-1 medida por bDNA (R2= 0.20, p<0.05) y RT-PCR (R2= 0.15, p<0.05). Los ensayos evaluados mostraron que ambas técnicas puedes ser empleadas indistintamente para el control de los pacientes VIH positivo.

The assay for quantification of plasma HIV-1 RNA are important for the control of patients infected, as well as the monitoring of the response to antiretroviral therapy. Therefore, the commercial assays used for this purpose must submit good correlation between to give place to the appropriate therapeutic management. In this study, we correlate the results obtained through the testing of signal amplification (bDNA) and real-time PCR (RT-PCR), two comercial technical approved by the FDA and with different targets of detection HIV-1. The validation was carried out with 180 clinical samples of patients referred to the INHRR. The results were compared with the subpopulation of lymphocytes TCD4+ determined by flow cytometry. The statistical analysis was performed using the program SPSS Statistics v10. It was observed good correlation between the tests studied (R2=0.961, p<0.05), with RT-PCR more sensitive. The quantitative differences in viral load between the techniques tested was less than 0.5 log10 copies/ml for the 89% of the samples, and >1 log10 copies/ml in only two patients. Additionally, it was found an inverse correlation between lymphocytes TCD4+ and viral load of HIV-1, measured by bDNA (R2= 0.20, p<0.05) and RT-PCR (R2= 0.15, p<0.05). Therefore, these assays can be employed for the patient control HIV.

Correlation between the ciaH gene of Streptococcus pneumoniae and the resistance toβ-lactam antibi-otics / 中华微生物学和免疫学杂志

Objective To construct a mutant strain of Streptococcus pneumoniae ( S.pneumoniae) with ciaH gene-knockout (ΔciaH) and to analyze the correlation between the ciaH gene and the bacterial re-sistance against β-lactam antibiotics.Methods The ciaH gene segament of S.pneumoniae strain ATCC6306 was amplified by PCR.The PCR product was sequenced after T-A cloning.A suicide plasmid pEVP3ciaH was constructed for the deletion of ciaH gene and then transformed into the ATCC 6306 strain by using the CaCl2 method .The mutant strain of S.pneumonia strain ATCC6306 with ciaH gene-knockout (ΔciaH) was genera-ted through homologous recombination , insertion inactivation and amphemycin screening , which was further identified by PCR , sequencing analysis and laser confocal microscopy .Double agar dilution method was used to detect the minimal inhibitory concentrations ( MICs ) of penicillin G ( PCN ) and cefotaxime ( CTX ) against theΔciaH mutant strain and the wild type strain .The differences between the MICs were further ana-lyzed.The changes of ciaH gene expression at mRNA level after treatment with 1/4 MIC of PCN or CTX were detected by real-time fluorescent quantitative RT-PCR ( qRT-PCR ) .Results The ciaH gene in the genomic DNA of the generated ΔciaH mutant strain was inactivated by insertion as indicated by PCR and se-quencing analysis .Results of the immunofluorescence assay showed that the ΔciaH mutant strain did not ex-press the CiaH protein .The MICs of PCN and CTX against the ΔciaH mutant strain were 32 μg/ml and 64μg/ml, respectively, which were significantly higher than that of the wild type strain (0.06 μg/ml and 1μg/ml) (P<0.01).The expression of ciaH gene at mRNA level was significantly elevated after treatment S.pneumoniae ATCC6306 strain with 1/4 MIC PCN or CTX (P<0.01).Conclusion The CiaH protein in the CiaH/CiaR two-component signaling system is involved in the resistance of S.pneumoniae against β-lac-tam antibiotics.

Predominant β-lactamase genotypes of Escherichia coli isolates and induction and inhibition mechanisms of β-lactamase gene expression / 中华流行病学杂志

Objective To understand the predominant β-lactamase genotypes and their carrying modes ofEscherichia coli isolates in Zhejiang province,and the effects of β-1actam antibiotics on inducing or histidine kinase inhibitor closantel (CLO) on inhibiting the expression of β-1actamase genes.Methods Micro-dilution method and E-test were applied to measure the resistant rate and minimal inhibitory concentration (MIC) in E.coli isolates against β-1actam antibiotics.PCR and sequence analysis of PCR products were conducted to detect the β-lactamase genotypes and their carrying modes.Real-time fluorescent quantitative RT-PCR and β-lactamase confirmation test were performed to determine the influence of 1/4 MIC penicillin and cefotaxime,and CLO on the transcription and expression of β-lactamase genes in the resistant E.coli isolates.Results Among the 462 E.coli strains isolated in Zhejiang,285 (61.7％) were resistant to penicillin,ampicillin,cefoxitin,cefotaxim and ceftazidime.In the 285 resistant isolates,the detection rate of TEM or CTX-M β-1actamase gene (83.2％ or 75.1％) was significantly higher than that of KPC,SHV or OXA β-lactamase gene (1.4％-10.2％) (P＜0.01) and the carrying rate of two or more β-1actamase genes (68.8％) was also significantly higher than that of single β-1actamase gene (31.2％) (P＜0.01),and 61.4％ of the resistant isolates carried TEM + CTX-M genes (P＜0.01).Except KPC gene,1/4 MIC of cefotaxim and penicillin induced a rapid increase of TEM-mRNA,CTX-M-mRNA,SHV-mRNA or OXA-mRNA levels (P＜0.01),but 50-500 μg/ml CLO inhibited these levels (P＜0.01).After pre-treatment with 100 μg/ml CLO,82.8％-85.6％ of the resistant isolates became sensitive to β-lactam antibiotics (P＜0.01),while the detection rate of β-lactamases was also decreased from 95.1％ to 16.1％ (P＜0.01).Conclusion TEM and CTX-M are the predominant β-lactamase genotypes in E.coli isolates in Zhejiang and TEM+CTX-M is the predominant carrying mode of β-lactamase genes.Low concentrations of β-lactam antibiotics can up-regulate the expression levels of β-lactamase genes in E.coli through bacterial two-component signaling systems,but this effect can be inhibited by CLO,a histidine kinase inhibitor.