Concentrations Of Cefotaxime Research Articles

Target attainment of cefotaxime in critically ill children with meningococcal septic shock as a model for cefotaxime dosing in severe pediatric sepsis

Reduced target attainment of β-lactam antibiotics is reported in critically ill patients. However, as target attainment of cefotaxime in severely ill pediatric sepsis patients may differ from adults due to age-related variation in pharmacokinetics, we aimed to assess target attainment of cefotaxime in this pilot study using meningococcal septic shock patients as a model for severe sepsis. Secondary analysis of prospectively collected data from a randomized controlled trial. Children with meningococcal septic shock (1 month to 18 years) included in this study received cefotaxime 100–150 mg/kg/day as antibiotic treatment. Left-over plasma samples were analyzed using LC-MS/MS to determine cefotaxime concentrations. MIC values from EUCAST were used to determine target attainment of cefotaxime for Neisseria meningitidis (0.125 mg/l), but also for Streptococcus pneumoniae (0.5 mg/l), Enterobacteriaceae (1 mg/l), and Staphylococcus aureus (4 mg/l). Target attainment was adequate when all samples exceeded MIC or fourfold MIC values. One thirty-six plasma samples of 37 severe septic shock patients were analyzed for cefotaxime concentrations. Median age was 2 years with a median PRISM-score of 24 and mortality of 24.8%. The median unbound cefotaxime concentration was 4.8 mg/l (range 0–48.7). Target attainment ranged from 94.6% for the MIC of N. meningitidis to 16.2% for fourfold the MIC S. aureus. Creatinine levels were significantly correlated with cefotaxime levels. Target attainment of cefotaxime with current dosing guidelines seems to be adequate for N. meningitidis but seems to fail for more frequently encountered pathogens in severely ill children.

Evaluation of synergism between Cefotaxime and Allium sativum against Extended-spectrum beta-lactamase and Ambler class C co-producers

In vitro study on the efficacy of zinc oxide and titanium dioxide nanoparticles against metallo beta-lactamase and biofilm producing Pseudomonas aeruginosaMary Grace Vincent, Neetu Peedikayil John, Narayanan PM, Vani C and Sevanan Murugan

Role of non-active site residues in maintaining New Delhi metallo-β-lactamase-1(NDM-1) function: an approach of site directed mutagenesis and docking.

New Delhi metallo-β-lactamase-1(NDM-1) has been known to hydrolyze nearly all β-lactam antibiotics, leading to multi drug resistant state. Hence, it is important to search its structure-function relation to control infections caused by such resistant bacterial strains. Mutagenesis is one of the approaches to explore it. No study has been performed to explore the role of non-active-site residues in the enzyme activity. This study includes mutations of three non-active site residues to comprehend its structure and function simultaneously. Three non-active-site laboratory mutants of NDM-1 were generated by site-directed mutagenesis. The MICs of cefotaxime, cefoxitin,imipenem and meropenem were reduced up to 4 fold for these mutants as compared to wild-type. The hydrolytic activity of mutants was also found to be reduced. Mutants showed a significant change in its secondary structure compared to wild type, as determined by CD spectrophotometer. Catalytic property and stability of these mutants were found to be reduced. Hence it revealed an imperative role of non-active-site residues in the enzymatic activity of NDM-1.

English

Potato is an important food crop of the world. Different viral, bacterial and fungal pathogens cause heavy economic losses of this crop every year. Potato has complex genetic makeup due to which induction of disease resistance through conventional breeding is difficult. Genetic manipulation through different transformation techniques is more precise and successful tool. In the present study different factors were investigated, which have an influence on potato transformation. The optimal dose of cefotaxime was found 500 mg/l which did not affected the growth of the potato tissues. The explants treated with Agrobacterium in the presence of acetosyringone resulted in higher frequency of transformation as compared to the explant without it. Two minutes time for co infection was found appropriate for optimum transformation efficiency. The two days cocultivation period along with 7 days preselection was found suitable for potato transformation. The putative tranformants regenerated on MS medium supplemented with 20 mg/L hygromycine and 500 mg/L cefotaxime, from nodal explants while the non-transformed tissue turned brown and gradually died after two or three sub culturing on the selection media containing selective antibiotic hygromycin. The shoots obtained on selection media shifted on root induction media supplemented with similar concentrations of hygromycin and cefotaxime, resulted complete plantlet formation after 10 days. It was observed that all the hygromycin positive plants also exhibited positive bands of desired size of 823 bp for chitinase gene, suggesting cotransformation of both genes in transformed plants

Significant role of Asn-247 and Arg-64 residues in close proximity of the active site in maintaining the catalytic function of CTX-M-15 type β-lactamase.

Members of Enterobacteriaceae cause antibiotic-resistant infections worldwide. One such marker, CTX-M-15, expressed by Enterobacteriaceae produces β-lactamases, which hydrolyze the cephalosporin group of antibiotics, such as cefotaxime, used in the treatment of both Gram-positive and negative bacterial infections. Amino acid residues present in close proximity of the active site might also play a major role in the structure and function of CTX-M-15, hence the objective of this study was to investigate the significance of two amino acid residues, Asn-247 and Arg-64, present near to the active site in the hydrolysis of cefotaxime. blaCTX-M-15, cloned from the E. cloacae strain, and using Polymerase Chain Reaction (PCR)-based site-directed mutagenesis, Asn247Val and Arg64Leu mutations were introduced. The minimum inhibitory concentrations of cefotaxime for the CTX-M-15 (N247V) and CTX-M-15 (R64L) mutants were reduced by 512 and 128 fold, respectively. Proteins/enzymes of wild-type CTX-M-15, CTX-M-15 (N247V) and CTX-M-15 (R64L) mutants were expressed and purified. Kinetic studies showed that the catalytic efficiencies of the N247V mutant and R64L mutant enzymes in the hydrolysis of cefotaxime were reduced by 89.66% and 71.11%, respectively. Circular dichroism spectroscopic studies showed considerable changes in the α-helical content of the mutant enzymes. A fluorescence study showed that N247V mutant-cefotaxime and R64L mutant-cefotaxime underwent complex formation with strong interactions. The study provides an understanding of the crucial role of the amino acid residues asparagine 247 and arginine 64 present in close proximity of the active site in the hydrolytic mechanism of CTX-M-15 type β-lactamases. Hence, Asn-247 and Arg-64 can be used as potential target sites for the design of inhibitory molecules against CTX-M-15-producing bacterial strains.

Transcriptome analysis of extended-spectrum \u03b2-lactamase-producing Escherichia coli and methicillin-resistant Staphylococcus aureus exposed to cefotaxime

Previous studies on bacterial response to antibiotics mainly focused on susceptible strains. Here we characterized the transcriptional responses of distinct cephalosporin-resistant bacteria of public health relevance to cefotaxime (CTX), a cephalosporin widely used in clinical practice. Adaptation to therapeutic concentrations of CTX (30 µg/ml) was investigated by RNA sequencing in mid-exponential phase cultures of a methicillin-resistant Staphylococcus aureus (MRSA) and two genetically diverse E. coli producing CTX-M-15 or CMY-2 β-lactamase following genome sequencing and annotation for each strain. MRSA showed the most notable adaptive changes in the transcriptome after exposure to CTX, mainly associated with cell envelope functions. This reprogramming coincided with a transient reduction in cell growth, which also occurred in the CMY-2-producing E. coli but not in the CTX-M-15-producing strain. Re-establishment of growth in the CMY-2 producer proceeded without any notable adaptive transcriptional response, while limited reprogramming of gene transcription was observed in the CTX-M-15 producer. Our data show that the transcriptional response of CTX-resistant bacteria to CTX depends on the bacterial species, level of resistance and resistance determinant involved. Gene products induced in the presence of CTX may play an essential role for bacterial survival during therapy and merit further investigation as possible targets for potentiating CTX.

Silymarin and curcumin effects on virulence and carbapenemase genes among multidrug-resistant Escherichia coli clinical isolates

Objective : Silymarin and curcumin antimicrobial properties have been previously described against some infectious agents. The aims of the current study were the investigation of the antibacterial effects of these compounds on the expression of fimA, cdt, bla IMP1 and bla OXA-48 and AcrAB-TolC genes among multidrug-resistant Escherichia coli clinical isolates. Methods : A total of five carbapenemase-producing E. coli strains were included. All of them carried bla IMP1 and bla OXA-48, ACR-AB, cdt, fimA and QepA genes. The antibiotic susceptibility test, imipenem, cefotaxime and ceftazidime minimum inhibitory concentration (MIC) and combine disk and Carba NP-test for carbapenemase production were performed. Silymarin and curcumin minimum inhibitory and bactericidal concentrations [MIC and minimum bactericidal concentration (MBC), respectively] were determined. The effect of 25 μg/ml concentration was also evaluated against gene expression. The quantitative real-time PCR was performed for the evaluation of genes expression. Results : Silymarin MIC and MBC were 256 and more than 256 μg/ml, respectively. Moreover, curcumin MIC and MBC concentrations were 128 and 256 μg/ml, respectively. Silymarin down-expressed the ACR-AB, cdt, fimA genes and QepA genes significantly (P < 0.05), but conferred no significant effect on bla IMP nor bla OXA-48 genes. Moreover, curcumin down-expressed the ACR-AB, QepA and bla IMP genes significantly (P < 0.05), but exhibited no significant effect against bla OXA-48, cdt and fimA genes. Conclusion : In this study, curcumin and silymarin sub-MIC concentrations could significantly inhibit the expression of the ACR-AB, cdt, fimA, QepA and bla IMP genes at 25 μg/ml. Combating bacterial virulence is a proper strategy not only to inhibit the spread of infections, but also to prevent the appearance and spread of antibiotic nonsusceptible strains.

Sublethal β-lactam antibiotics induce PhpP phosphatase expression and StkP kinase phosphorylation in PBP-independent β-lactam antibiotic resistance of Streptococcus pneumoniae

StkP and PhpP of Streptococcus pneumoniae have been confirmed to compose a signaling couple, in which the former is a serine/threonine (Ser/Thr) kinase while the latter was annotated as a phosphotase. StkP has been reported to be involved in penicillin-binding protein (PBP)-independent penicillin resistance of S. pneumoniae. However, the enzymatic characterization of PhpP and the role of PhpP in StkP-PhpP couple remain poorly understood. Here we showed that 1/4 minimal inhibitory concentration (MIC) of penicillin (PCN) or cefotaxime (CTX), the representatives of β-lactam antibiotics, could induce the expression of stkP and phpP genes and phosphorylation of StkP in PCN/CTX-sensitive strain ATCC6306 and three isolates of S. pneumoniae (MICs: 0.02–0.5 μg/ml). The product of phpP gene hydrolyzed PP2C type Ser/Thr phosphotase-specific RRA (pT)VA phosphopeptide substrate with the Km and Kcat values of 277.35 μmoL/L and 0.71 S-1, and the hydrolytic activity was blocked by sodium fluoride, a PP2C type Ser/Thr phosphatase inhibitor. The phosphorylation levels of StkP in the four phpP gene-knockout (ΔphpP) mutants were significantly higher than that in the wild-type strains. In particular, the MICs of PCN and CTX against the ΔphpP mutants were significantly elevated as 4–16 μg/ml. Therefore, our findings confirmed that sublethal PCN and CTX act as environmental inducers to cause the increase of phpP and stkP gene expression and StkP phosphorylation. PhpP is a PP2C type Ser/Thr protein phosphatase responsible for dephosphorylation of StkP. Knockout of the phpP gene results in a high level of StkP phosphorylation and PBP-independent PCN/CTX resistance of S. pneumoniae.

Population Pharmacokinetics of Cefotaxime and Dosage Recommendations in Children with Sickle Cell Disease.

The pharmacokinetic profile of most drugs is dependent on the patient's covariates and may be influenced by the disease. Cefotaxime is frequently prescribed in pediatric patients with sickle cell disease (SCD), characterized by vaso-occlusive complications, chronic hemolytic anemia, and a defective immunological function predisposing the individual to severe infection. Data on the impact of the disease on the disposition of cefotaxime are missing. In the present study, our aims were to determine cefotaxime pharmacokinetics when prescribed to children with SCD for suspected or proven bacterial infection, identify significant covariates, and perform Monte Carlo simulations to optimize the drug dosage. Cefotaxime serum concentrations were measured in 78 pediatric SCD patients receiving cefotaxime intravenously at a daily dose of 200 mg/kg of body weight in three or four divided doses over 30 min. A total of 107 concentrations were available for pharmacokinetic analysis. A population pharmacokinetic model was developed with NONMEM software and used for Monte Carlo simulations. Cefotaxime concentrations ranged from 0.05 to 103.7 mg/liter. Cefotaxime pharmacokinetics were best described by a one-compartment model: the median estimated weight-normalized volume of distribution and clearance were 0.42 liter/kg (range, 0.2 to 1.1 liter/kg) and 0.38 liter/h/kg (range, 0.1 to 1.2 liter/h/kg). Cefotaxime clearance increased by 22% in patients with acute chest syndrome. Dosing optimization, performed using EUCAST MIC susceptibility breakpoints, showed that a dose of 100 mg/kg/6 h should be used, depending on the patient's characteristics and clinical presentation, in order to reach a value of the percentage of time that the drug concentration exceeded the MIC under steady-state pharmacokinetic conditions of 80% in 80% of the patients when targeting sensitive Gram-positive cocci and Gram-negative bacilli with MICs of 1 mg/liter or below.

Antimicrobial Susceptibility Patterns of Enteroaggregative E. coli, as the Most Common Diarrheagenic E. coli, Associated to Gastroenteritis Outbreaks in Iran

Background: Acute diarrhea, a leading cause of morbidity and mortality worldwide, still remains a major global health problem, especially among children in the developing countries. Diarrheagenic E. coli represent one of the most common etiological causes of diarrhea in children worldwide. Objectives: This study was conducted in order to determine the rate of Enteroaggregative E. coli (EAEC) among 50 E. coli isolates as well as its antimicrobial resistance patterns. Methods: A total of 50 Escherichia coli strains had been isolated among children under 5 years of age during 75 reported outbreaks in various provinces of Iran from October 2013 to May 2014. PCR was employed for the identification of different groups of diarrheagenic E. coli. Antimicrobial susceptibility testing was performed using disc diffusion methods. In addition, extended spectrum beta-lactamase (ESBL) production ability was checked by way of combination disc methods of CLSI. Minimum inhibitory concentration of cefotaxime, ceftriaxone, and ceftazidime in EAEC with the ability of ESBL production was determined using the micro-broth dilution method of CLSI. Results: Out of the 50 E. coli isolates, 17 were identified as Enteroaggregative E. coli (EAEC) in that they were positive for at least 1 of the 2 tested virulent genes: agg and aap. ESBL production ability was observed in 4/17 (23.5%) EAEC isolates. MIC of cefotaxime and ceftriaxone in ESBL positive EAEC varied between 8 - 32 µg/mL and 8 - 64 µg/mL, respectively. Resistance to ampicillin and nalidixic-acid (47.1%), trimethoprim/sulfamethoxazole (41.2%), and ciprofloxacin (11.8%) was observed among the EAEC isolates. No evidence of resistance to gentamycin and meropenem was detected. Conclusions: This research has revealed that the most common type of diarrheagenic E. coli among children, who were affected in the diarrheal outbreak in different cities of the country, is Enteroaggregative E. coli (34%). The rate of ESBL positive cases in EAEC isolates were 23.5 %.

Application of a System for Targeting Fe-Dependent Superoxide Dismutase and Choline Oxidase Enzymes to Chloroplast as a Strategy for Effective Plant Resistance to Abiotic Stresses

The plastids involved in photosynthesis and other essential metabolic processes are the cellular compartments most susceptible to abiotic stress factors with adverse effects in plants. In order to protect the chloroplast compartment, the plants of the Belyi Naliv tomato cultivar and the Darenka potato cultivar were transformed with genes for Fe-dependent superoxide dismutase and choline oxidase with the use of the method for plant genetic engineering. These target genes were equipped with signal sequences directing the proteins into the plastid compartment. The experimental results have demonstrated the optimization of the agrobacterium-mediated transformation method for the analyzed tomato and potato cultivars. The naturally growing leaves and stems of the mature plants proved to be the most effective explants to obtain the regenerants. The highest regeneration frequency in the explants was reached with the use of a medium containing 5 mg L–1 BAP, 0.1 mg L–1 NAA, and 1 mg L–1 zeatin. Augmentin and timentin were equally efficient among the antibiotics tested for the inhibition of the agrobacterium; the concentration of 200 mg L–1 in the culture medium was sufficient to eliminate the agrobacterium. In addition, they had no inhibitory effects on the shoot regeneration process. However, the cefotaxime concentration required to inhibit the agrobacterium should be 500 mg L–1 and higher. Moreover, this antibiotic at the concentration of 100 mg L–1 was proven to inhibit the regenerant growth.

Study of pandrug and heavy metal resistance among E. coli from anthropogenically influenced Delhi stretch of river Yamuna.

Escalating burden of antibiotic resistance that has reached new heights present a grave concern to mankind. As the problem is no longer confined to clinics, we hereby report identification of a pandrug resistant Escherichia coli isolate from heavily polluted Delhi stretch of river Yamuna, India. E. coli MRC11 was found sensitive only to tobramycin against 21 antibiotics tested, with minimum inhibitory concentration values >256 μg/mL for amoxicillin, carbenicillin, aztreonam, ceftazidime and cefotaxime. Addition of certain heavy metals at higher concentrations were ineffective in increasing susceptibility of E. coli MRC11 to antibiotics. Withstanding sub-optimal concentration of cefotaxime (10 μg/mL) and mercuric chloride (2 μg/mL), and also resistance to their combinatorial use, indicates better adaptability in heavily polluted environment through clustering and expression of resistance genes. Interestingly, E. coli MRC11 harbours two different variants of blaTEM (blaTEM-116 and blaTEM-1 with and without extended-spectrum activity, respectively), in addition to mer operon (merB, merP and merT) genes. Studies employing conjugation, confirmed localization of blaTEM-116, merP and merT genes on the conjugative plasmid. Understanding potentialities of such isolates will help in determining risk factors attributing pandrug resistance and strengthening strategic development of new and effective antimicrobial agents.

Considerable variation of trough \u03b2-lactam concentrations in older adults hospitalized with infection\u2014a prospective observational study

In older adults, few studies confirm that adequate concentrations of antibiotics are achieved using current dosage regimens of intravenous β-lactam antibiotics. Our objective was to investigate trough concentrations of cefotaxime, meropenem, and piperacillin in older adults hospitalized with infection. We included 102 patients above 70 years of age. Total trough antibiotic concentrations were measured and related to suggested target intervals. Information on antibiotic dose, patient characteristics, and 28-day outcomes were collected from medical records and regression models were fitted. Trough concentrations for all three antibiotics exhibited considerable variation. Mean total trough concentrations for cefotaxime, meropenem, and piperacillin were 6.5 mg/L (range 0–44), 3.4 mg/L (range 0–11), and 30.2 mg/L (range 1.2–131), respectively. When a target range of non-species-related breakpoint − 5× non-species-related breakpoint was applied, only 36% of patients had both values within the target range. Regression models revealed that severe sepsis was associated with varying concentration levels and increasing age and diminishing kidney function with high concentration levels. The study was not powered to demonstrate consequences in clinical outcomes. Conclusively, in older adults treated with cefotaxime, meropenem, or piperacillin-tazobactam, trough antibiotic concentrations varied considerably. Better predictors to guide dosing regimens of β-lactam antibiotics or increased use of therapeutic drug monitoring are potential ways to address such variations.

Extended-spectrum β-lactamase-producing Escherichia coli contributes to the survival of cefotaxime-susceptible E. coli under high concentrations of cefotaxime by acquisition of increased AmpC expression.

Extended-spectrum β-lactamase-producing Escherichia coli (ESBL-E) are becoming increasingly widespread in Vietnam. Antibiotics are detected in many Vietnamese foods; however, the effect of ESBL-E and antibiotic consumption on intestinal bacteria has not been studied sufficiently. Here, we investigated the effect of oral administration of ESBL-E (TB19) and cefotaxime on luminescence-emitting cefotaxime-sensitive E. coli (X14). Mice were given water containing TB19 and then received three injections of 1.0×108 CFU of X14 harboring a luciferase gene. The mice were administered 100 μg of cefotaxime and luminescent bacteria were monitored over 24 h, following which luminescent bacteria were isolated from mouse feces. Luminescence continued to be detected in mice administered TB19 24 h after cefotaxime ingestion. Fecal analysis revealed two types of luminescent colonies: cefoxitin-resistant E. coli (X14-R) and Pseudomonas aeruginosa. Pulse-field gel electrophoresis confirmed that X14-R was a clonal strain of X14, suggesting that X14 survived using ESBLs originating from TB19 and acquired cefoxitin resistance due to cefotaxime consumption. Moreover, in vitro analysis of X14 indicated that expression of the ampC gene was upregulated by cefotaxime. Overall, ESBL-E and cefotaxime promoted the expansion of cefoxitin-resistant E. coli in the absence of plasmid-mediated gene transfer.

Treatment with Cefotaxime Affects Expression of Conjugation Associated Proteins and Conjugation Transfer Frequency of an IncI1 Plasmid in Escherichia coli.

Horizontal gene transfer (HGT) is the major mechanism responsible for spread of antibiotic resistance. Antibiotic treatment has been suggested to promote HGT, either by directly affecting the conjugation process itself or by selecting for conjugations subsequent to DNA transfer. However, recent research suggests that the effect of antibiotic treatment on plasmid conjugation frequencies, and hence the spread of resistance plasmids, may have been overestimated. We addressed the question by quantifying transfer proteins and conjugation frequencies of a blaCTX−M−1 encoding IncI1 resistance plasmid in Escherichia coli MG1655 in the presence and absence of therapeutically relevant concentrations of cefotaxime (CTX). Analysis of the proteome by iTRAQ labeling and liquid chromatography tandem mass spectrometry revealed that Tra proteins were significantly up-regulated in the presence of CTX. The up-regulation of the transfer machinery was confirmed at the transcriptional level for five selected genes. The CTX treatment did not cause induction of the SOS-response as revealed by absence of significantly regulated SOS associated proteins in the proteome and no significant up-regulation of recA and sfiA genes. The frequency of plasmid conjugation, measured in an antibiotic free environment, increased significantly when the donor was pre-grown in broth containing CTX compared to growth without this drug, regardless of whether blaCTX-M-1 was located on the plasmid or in trans on the chromosome. The results shows that antibiotic treatment can affect expression of a plasmid conjugation machinery and subsequent DNA transfer.

Antibiotics and common antibacterial biocides stimulate horizontal transfer of resistance at low concentrations

There is a rising concern that antibiotics, and possibly other antimicrobial agents, can promote horizontal transfer of antibiotic resistance genes. For most types of antimicrobials their ability to induce conjugation below minimal inhibitory concentrations (MICs) is still unknown. Our aim was therefore to explore the potential of commonly used antibiotics and antibacterial biocides to induce horizontal transfer of antibiotic resistance. Effects of a wide range of sub-MIC concentrations of the antibiotics cefotaxime, ciprofloxacin, gentamicin, erythromycin, sulfamethoxazole, trimethoprim and the antibacterial biocides chlorhexidine digluconate, hexadecyltrimethylammoniumchloride and triclosan were investigated using a previously optimized culture-based assay with a complex bacterial community as a donor of mobile resistance elements and a traceable Escherichia coli strain as a recipient. Chlorhexidine (24.4μg/L), triclosan (0.1mg/L), gentamicin (0.1mg/L) and sulfamethoxazole (1mg/L) significantly increased the frequencies of transfer of antibiotic resistance whereas similar effects were not observed for any other tested antimicrobial compounds. This corresponds to 200 times below the MIC of the recipient for chlorhexidine, 1/20 of the MIC for triclosan, 1/16 of the MIC for sulfamethoxazole and right below the MIC for gentamicin. To our best knowledge, this is the first study showing that triclosan and chlorhexidine could stimulate the horizontal transfer of antibiotic resistance. Together with recent research showing that tetracycline is a potent inducer of conjugation, our results indicate that several antimicrobials including both common antibiotics and antibacterial biocides at low concentrations could contribute to antibiotic resistance development by facilitating the spread of antibiotic resistance between bacteria.

Study creating and cloning hairy root lines in Talinum paniculatum plants

Talinum paniculatum Gaertn. contains flavonoid and saponins that have strong antioxidant properties, which are used to treat a number of conditions such as inflammation, allergies, stomach ulcers, ... However, the amount of flavonoid synthesized naturally in Talinum paniculatum plants is very low (about 0.897 mg /g fresh leaves). Therefore a method has been proposed for enhancing flavonoid content in Talinum paniculatum plants by applying tissue culture technique to produce the hairy roots to enhance biomass. This study present the results of optimization of the gene transfer process to create the hairy root lines through Agrobacterium rhizogenes (A. rhizogenes) in Talinum paniculatum plants. Of the three types of materials that infect by A. rhizogenes (cotyledon, stem, leaf tissue), leaf tissue is a suitable material for transforming and inducing hairy roots. Density of bacteria corresponding to OD600 value=0.6; concentration AS 100 μmol/l; Infection time of 10 minutes; 2 days of co-culture; cefotaxime concentrations of 500 mg/l are suitable conditions for inducing hairy roots from leaf tissue. In state of the liquid MS medium without growth regulator, shaking culture conditions are suitable for hairy roots growth. The test result of presence of rolC gene by PCR and the absence of the virD2 gene asserted that 5 lines of hairy roots were produced from Talinum paniculatum plants.
 

O-2 Population and developmental pharmacokinetic analysis to evaluate and optimise cefotaxime dosing regimen in neonates and young infants

Background Cefotaxime is one of the most frequently prescribed antibiotics for the treatment of Gram-negative bacterial sepsis in neonates. However, the dosing regi-mens routinely used in clinical practice vary considerably. The objective of the present study was to conduct a population pharmacokinetic study of cefotaxime in neonates and young infants in order to evaluate and optimise the dosing regimen. Methods An opportunistic sampling strategy com-bined with population pharmacokinetic analysis using NONMEM software was performed. Cefotaxime concentrations were measured by high-performance liquid chromatography tandem mass spectrometry. Developmental pharmacokinetics-pharmacodynamics, the microbiological pathogens, and safety aspects were taken into account to optimise the dose. Results The pharmacokinetic data from 100 neonates (gestational age [GA] range, 23 to 42 weeks) were modeled with an allometric two compartment model with first-order elimination. The median values for clearance and volume of distribution at steady state were 0.12 litre/h/kg of body weight and 0.64 litre/kg, respectively. The covariate analysis showed that current weight, GA, and postnatal age [PNA] had significant impacts on ce-fotaxime pharmacokinetics. Monte Carlo simulations demonstrated that the current dose recommendations underdosed the older newborns. A model-based dosing regimen of 50 mg/kg twice a day to four times a day, according to GA and PNA, was established. The associated risk of overdose for the proposed dosing regimen was 0.01%. Conclusion We determined the population pharma cokinetics of cefotaxime and established a model based dosing regimen to optimise treatment for neonates and young infants.

Clinical Pharmacology of Ceftriaxone in Neonates and Infants: Effects and Pharmacokinetics

Cefotaxime is a bactericidal third generation cephalosporin has a broad-spectrum activity against gram-positive microorganisms and exceptional activity against most gram-negative microorganisms. Cefotaxime is widely considered to be the antibiotic of choice for the management of neonatal meningitis and sepsis caused by gram-negative bacteria. Cefotaxime is active against Neisseria meningitis, Streptococcus pneumoniae, Haemophilus influenzae, Salmonella specimens, Staphylococcus, Enterobacter species, Haemophilus parainfluenzae, Pseudomonas aeruginosa, Escherichia coli, Citrobacter freundii, and Klebsiella pneumoniae. In neonates, the recommended dose of cefotaxime is 25 mg/kg every 6 hours by intravenous or intramuscular administration. Some authors administered cefotaxime at a daily dose of 150 or 300 mg/kg. After the intravenous administration of 50 mg/kg cefotaxime every 6 hours, the serum concentrations of this antibiotic are 56.9+28.7 µg/ml at 1 hour and 3.66+5.65 µg/ml at 6 hours after the administration. The cerebrospinal fluid concentration of cefotaxime, measured 1 hour after the intravenous administration of 50 mg/kg cefotaxime, is 3.72+5.57 µg/ml. The MIC50 (µg/ml) and the MBC50 (µg/ml) are 0.024+0.026 and 0.064+0.054, respectively, for Haemophilus influenzae, 0.062+0.034 and 0.240+0.027, respectively, for Streptococcus pneumoniae and 0.057+0.088 and 0.283+0.44, respectively, for Neisseria meningitis. In neonates, the half-life of cefotaxime is 2 to 6 hours, it varies with gestational and postnatal ages, and the clearance and distribution volume are 0.074+0.03 l/h/kg and 0.461+0.027 l/kg, respectively. Cefotaxime diffuses in tissues and penetrates into the cerebrospinal fluid. This antibiotic is safe and well tolerated in neonates. The aim of this study is to review the effects and pharmacokinetics of cefotaxime in neonates and infants.

The Transient Multidrug Resistance Phenotype of Salmonella enterica Swarming Cells Is Abolished by Sub-inhibitory Concentrations of Antimicrobial Compounds.

Swarming motility is the rapid and coordinated multicellular migration of bacteria across a moist surface. During swarming, bacterial cells exhibit increased resistance to multiple antibiotics, a phenomenon described as adaptive or transient resistance. In this study, we demonstrate that sub-inhibitory concentrations of cefotaxime, ciprofloxacin, trimethoprim, or chloramphenicol, but not that of amikacin, colistin, kanamycin or tetracycline, impair Salmonella enterica swarming. Chloramphenicol-treated S. enterica cells exhibited a clear decrease in their flagellar content, while treatment with other antibiotics that reduced swarming (cefotaxime, ciprofloxacin, and trimethoprim) inhibited polar chemoreceptor array assembly. Moreover, the increased resistance phenotype acquired by swarming cells was abolished by the presence of these antimicrobials. The same occurred in cells treated with these antimicrobial agents in combination with others that had no effect on swarming motility. Our results reveal the potential of inhibiting swarming ability to enhance the therapeutic effectiveness of antimicrobial agents.