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OBJECTIVE To provide reference for the adjustment of antibiotic treatment regimens， identification of adverse reactions， and individualized pharmaceutical care for melioidosis sepsis （MS）. METHODS Clinical pharmacists participated in the intensive and eradicating therapeutic processes for an MS patient by using blood concentration and gene detection. Based on the literature， antibiotic treatment regimens of MS were adjusted by determining the blood concentrations of β-lactam and trimethoprim/ sulfamethoxazole （TMP/SMZ） and calculating PK/PD parameters. The causes of adverse drug reactions were analyzed and addressed by detecting drug-related gene polymorphisms through high-throughput sequencing. RESULTS Clinical pharmacists used blood concentration and genetic testing methods to propose adjustments to imipenem-cilastatin sodium dosage and analyze the causes of various adverse drug reactions. PK/PD targets were calculated by measuring the blood concentrations of β-lactam and TMP/SMZ. Clinical pharmacists explained to clinical doctors the compliance status of patients with melioidosis in sepsis and non- sepsis stages through reviewing guidelines and literature； the results of blood concentration and genetic test were used to analyze the correlation of neurotoxicity of MS patients with B14） IMP cmin， and it was found that nephrotoxicity was not related to the cmax of TMP/SMZ， but to the patient’s water intake. After whole-process antibiotic treatment， the patient’s condition improved and was discharged， and the adverse reactions were effectively treated. CONCLUSIONS Clinical pharmacists use blood concentration and genetic tests to assist clinicians in formulating MS treatment regimens， and provide whole-course pharmaceutical care for a MS patient. This method has improved the safety and effectiveness of clinical drug therapy.
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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.
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【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.
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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.
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【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.
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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.
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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.
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Background: Every time an antibiotic is used, whether appropriately or not, the probability of the development and spread of antibiotic resistant bacteria is increased. Thus, multidrug resistant bacteria particularly ESBL (Extended spectrum βlactamase), Amp C and carbapenemases producing gram negative bacilli have emerged as a major health problem all over the world. Considering new treatment options as a carbapenems sparing and resistance prevention modality, this study was aimed to know the in vitro susceptibility pattern of Cefepime/Tazobactam (CPM/TZ) in comparison to other β-Lactam/ β-Lactamase inhibitors (BL/BLI) and carbapenems against GNB.Methods: A prospective study was conducted on all clinical samples received for a period of about 1 year. Identification and susceptibility of all isolates was done by Vitek 2 Compact system. Susceptibility of CPM/ TZ was done by disc diffusion method on the basis of CLSI guidelines. Both fermenters (E. coli and Klebsiella pneumoniae) and non-fermenters (Acintobacter baumanii and Pseudomonas aeruginosa) were included in the study.Results: Out of 550 GNB isolates the most common was E. coli (61.8%), Acintobacter baumanii (16%), Klebsiella pneumoniae (14.9%) and Pseudomonas aeruginosa (7.3%). Cefepime/tazobactam had a much higher susceptibility of 68% compared to cefepime (28%). Among the BL/BLI combinations tested cefepime/tazobactam (68%) showed the maximum percentage of susceptibility followed by cefoperazone/sulbactam (61.5%) and piperacillin/tazobactam (57.6%). Amongst all GNB isolates cefepime/tazobactam (68%) sensitivity was very much comparable to imipenem (71.8%) and meropenem (69.6%).Conclusions: CPM/TZ exhibited the best in vitro activity in comparison to the other BL/BLI. This new combination of cefepime/tazobactam appears to be a promising alternative therapeutic option to carbapenems. Clinical studies are needed to confirm this in vitro study result.
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Objective To investigate the antimicrobial activities of clove oil alone and in combination with three kinds of β-lactam antibiotics (amoxicillin, cephalexin, and cefepime) against methicillin-resistant Staphylococcus aureus (MRSA). Methods The minimum inhibitory concentrations (MICs) of clove oil alone and in combination with three kinds of β-lactam antibiotics against two standard MRSA and 32 MRSA isolated from clinic were determined by 96-well plate micro-dilution method. The fractional inhibitory concentrations (FICs) of clove oil and three kinds of β-lactam antibiotics were determined by using the micro-chessboard method. The growth curve of MRSA ATCC43300 effected by clove oil or clove oil combined with cephalexin was analyzed. Results Clove oil showed significant anti-MRSA activity in vitro, with MIC of 0.25 mg/mL and 0.51 mg/mL. The FICs were mainly distributed in the range of ≤ 0.5 and 0.5 to 1, and the synergy rates were 58.8%, 97.0%, and 64.7%, when the clove oil was combined with amoxicillin, cephalexin and cefepime, respectively. Clove oil enhanced the activity of β-lactam antibiotics against MRSA significantly, and reduced the dosage of it. The growth curve showed that the clove oil significantly inhibited the growth of MRSA, and prolonged its lag phase. And the effect showed a significant dose-effect relationship. The growth of MRSA was nearly inhibited when 1/4 MIC cefepime combined with 1/4 MIC clove oil. Conclusion Clove oil not only could exhibit strong anti-MRSA activity itself, but could enhance the activity of β-lactam antibiotics against MRSA. Hence, clove oil would be a potential new drug, which can be used as a new drug for preventing and treating MRSA infection.
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Objective To analyze the susceptibility situation of bifidobacteria and lactobacilli from child intestinal tract on β-lactam/β-lactamase inhibitor complex.Methods According to the method of the Bergey Bacterial Identification Manual,45 strains of bifidobacteria and 39 strains of lactobacilli were isolated from the stool specimens of 36 healthy children.The susceptibility tests of bifidobacteria and lactobacilli to ampicillin,amoxicillin/clavulanate,ampicillin/sulbactam,piperacillin,piperacillin/tazobactam,ticarcillin,ticarcillin/clavulanate,cefoperazone and cefoperazone/sulbactam were performed by adopting the E-test method.Then the statistical analysis was conducted.Results The sensitivity percentages of 45 strains of bifidobacteria to ampicillin,amoxicillin/clavulanate,ampicillin/sulbactam,piperacillin,piperacillin/tazobactam,ticarcillin,ticarcillin/clavulanate and cefoperazone were 77.78％,95.56％,88.89％,73.33％,91.11％,68.89％,84.44％ and 82.22％ respectively,which of 39 strains of lactobacilli to above antibiotic drugs were 74.36％,94.87％,92.31％,71.79％,92.31％,69.23％,89.74％ and79.49％,respectively.Except having no judgment due to without the CLSI drug susceptibility MIC interpretation criteria of cefoperazone/sulbactam,the sensitivity percentages of other β-lactam/β-lactamase inhibitor complex were higher than those of single β-lactam antibi otics,the sensitive number P values of bifidobacteria in ampicillin with amoxicillin/clavulanate and piperacillin with piperacillin/tazobactam were 0.01 and 0.03 respectively,which of lactobacilli in ampicillin with amoxicillin/clavulanate,ampicillin with ampicillin/sulbactam,piperacillin with piperacillin/tazobactam,ticarcillin with ticarcillin/clavulanate were 0.01,0.03,0.02 and 0.03 respectively.Conclusion β-lactam/β-lactamase inhibitors complex has stronger effect for inhibiting child intestinal tract bifidobacteria and lactobacilli than single β-lactam antibiotics.
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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.
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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.
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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.
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To introduce peptidoglycan recycling and the β-lactams resistance mechanisms of bacteria, so that some help would be supplied to corresponding scientific workers and university teachers. By searching literatures, combined with our own studies, the bactericidal mechanisms of β-lactams and the resistance mechanisms of bacteria to β-lactams were summarized. The bactericidal activity of β-lactams is resulted from the inhibition of cell wall biosynthesis through combination with penicillin binding proteins such as transpeptidase destruction of peptidoglycan balances between biosynthesis and hydrolysis. The drug resistance of bacteria is resulted from the induction of β-lactamase, expression of out-pumping proteins, increase of outmembrane permeability, and modification of antibiotic target proteins. The proteins related to peptidoglycan recycling, such as transpeptidase and glycosyltransferase, would be potential targets for screening new β-lactams. The proteins related to β-lactams resistance, such as β-lactamase, would be potential targets for screening adjuvant drugs of β-lactams.
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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.
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β-lactam compounds exhibit good antibacterial activity, which aroused widespread attention.Recently, the researches on the biological activities of beta-lactam derivatives have made great development.In this paper, we will review the recent research progress of β-lactam derivatives in the field of anti-tumor, anti-HIV, anti-tuberculosis, anti-parasitic, anti-diabetes, antithrombotic, plasma lipids regulation and treatment on nervous system diseases.
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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.
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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.
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ObjectiveTo investigate the incidence and risk factors of antibiotic-associated diarrhea (AAD) of pediatric patients with severe bacterial pneumonia.MethodsClinical data of 1086 pediatric patients with severe bacterial pneumonia from January 2010 through January 2014 were recruited. The incidence and risk factors of AAD were retrospectively analyzed. ResultsThe incidence of AAD in 1086 pediatric patients with severe bacterial pneumonia was 36.74%. The incidence of AAD in patients younger than 2 years old were higher than that in those older than 2 years, once or more times of mechanical venti-lation history were higher than that with no arrangements of this treatment, administering of combined antibiotics therapy were higher than that with single antibiotics, and the incidence of AAD due to amoxicillin/clavulanate, piperacillin/tazobactam, cefo- perazone/sulbactam in pediatric patients were 43.55%, 43.75%, and 45.03%, respectively. Three β-lactam/β-lactamase inhibitors above were risk factors of AAD through multivariate Logistic regression analysis.ConclusionThe high incidence of AAD in pediatric patients with severe bacterial pneumonia was associated with some risk factors, including younger than 2 years old, me-chanical ventilation, combined antibiotics therapy and administration of β-lactam/β-lactamase inhibitor (amoxicillin/clavulanate, piperacillin/tazobactam, cefoperazone/sulbactam).
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Objective To investigate the clinical efficacy ofβ-lactam combined with macrolides antibiotics in treatment of severe community-acquired pneumonia (CAP) in children. Methods Children with severe CAP on admission between 2012 February and 2012 April were divided into treatment group and control group. With the same symptom specific supportive treat-ment, the patients in the treatment group were treated with both cefmetazole and azithromycin, while the patients in the control group were treated with cefmetazole alone. The total effective rate, number of days of symptoms and signs disappeared and num-ber of days of hospitalization were observed. Results The total effective rate was 87.8%in the trearment group and 61.3%in the control group with significant difference (P<0.05). Compared with control group, the recovery time of temperature, time of pulmonary rale disappearing and cough retraction were reduced (P<0.05). As well as the number of days of hospitalization was decreased (P<0.05). Conclusions The treatment of severe CAP in children with combination of azithromycin and cefmetazole results in better curative effect. A combined medication ofβ-lactam and macrolides antibiotics may be rational and effective.