Our library of drug research abstracts drawn from the medical literature is updated on a regular schedule, and you can be assured that new ampicillin research articles will be listed here shortly after becoming available to us.
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Medical research on ampicillin
Heat inactivation of beta-lactam antibiotics in milk.
J Food Prot. 2008 Jun; 71(6): 1193-8
Zorraquino MA, Roca M, Fernandez N, Molina MP, Althaus R
The presence of residues of antimicrobial substances in milk is one of the main concerns of the milk industry, as it poses a risk of toxicity to public health, and can seriously influence the technological properties of milk and dairy products. Moreover, the information available on the thermostability characteristics of these residues, particularly regarding the heat treatments used in control laboratories and the dairy industry, is very scarce. The aim of the study was, therefore, to analyze the effect of different heat treatments (40 degrees C for 10 min, 60 degrees C for 30 min, 83 degrees C for 10 min, 120 degrees C for 20 min, and 140 degrees C for 10 s) on milk samples fortified with three concentrations of nine beta-lactam antibiotics (penicillin G: 3, 6, and 12 microg/liter; ampicillin: 4, 8, and 16 microg/liter; amoxicillin: 4, 8, and 16 microg/liter; cloxacillin: 60, 120, and 240 microg/liter; cefoperazone: 55, 110, and 220 microg/liter; cefquinome: 100, 200, and 400 microg/liter; cefuroxime: 65, 130, and 260 microg/liter; cephalexin: 80, 160, and 220 microg/ liter; and cephalonium: 15, 30, and 60 microg/liter). The method used was a bioassay based on the inhibition of Geobacillus stearothermophilus var. calidolactis. The results showed that heating milk samples at 40 degrees C for 10 min hardly produced any heat inactivation at all, while the treatment at 83 degrees C for 10 min caused a 20% loss in penicillin G, 27% in cephalexin, and 35% in cefuroxime. Of the three dairy industry heat treatments studied in this work, low pasteurization (60 degrees C for 30 min) and treatment at 140 degrees C for 10 s only caused a small loss of antimicrobial activity, whereas classic sterilization (120 degrees C for 20 min) showed a high level of heat inactivation of over 65% for penicillins and 90% for cephalosporins.
Plant-derived compounds inactivate antibiotic-resistant Campylobacter jejuni strains.
J Food Prot. 2008 Jun; 71(6): 1145-9
Ravishankar S, Zhu L, Law B, Joens L, Friedman M
Sixty-three Campylobacter jejuni isolates were screened for their resistance to the antibiotics ampicillin, cefaclor, ciprofloxacin, erythromycin, gentamycin, tetracycline, and trimethoprim-sulfamethoxazole. Based on this screen, the resistant strains D28a and H2a and the nonresistant strain A24a were selected for evaluation of their resistance and susceptibility to inactivation by cinnamaldehyde and carvacrol, the main constituents of plant-derived cinnamon and oregano oils, respectively. Different concentrations (0.05, 0.1, and 0.2% [vol/vol] in sterile phosphate-buffered saline) of cinnamaldehyde and carvacrol were added to C. jejuni cultures with initial populations of 10(4) CFU/ml. The samples were then mixed thoroughly and incubated at 37 degrees C. Viable bacterial populations were enumerated at incubation periods of 0, 30, 60, and 120 min. The results indicate that the extent of inhibition of microbial survival was related to both the nature and concentration of antimicrobials and the incubation time. Both cinnamaldehyde and carvacrol exhibited rapid antimicrobial activity against both antibiotic-resistant and non-resistant C. jejuni strains, at concentrations of approximately 0.1% and higher. The antimicrobial efficacy of cinnamaldehyde was greater than that of carvacrol. The possible significance of the results for microbiological food safety is discussed.
Novel beta-Lactam Antibiotics Synthesized by Amination of Catechols Using Fungal Laccase.
Chem Pharm Bull (Tokyo). 2008 Jul; 56(7): 902-7
Mikolasch A, Wurster M, Lalk M, Witt S, Seefeldt S, Hammer E, Schauer F, Jülich WD, Lindequist U
Novel cephalosporins, penicillins, and carbacephems were synthesized by amination of catechols with amino-beta-lactams like cefadroxil, amoxicillin, ampicillin and the structurally related carbacephem loracarbef using laccase from Trametes sp. All isolated monoaminated products inhibited the growth of several Gram positive bacterial strains in the agar diffusion assay, among them methicillin-resistant Staphylococcus aureus strains and vancomycin-resistant Enterococci. Observed differences in the cytotoxicity and in vivo activity in a "Staphylococcus-infected, immune suppressed mouse" model are discussed.
Wei Sheng Wu Xue Bao. 2008 Apr 4; 48(4): 486-91
Cai X, Li Y, Xuan W, Wang X
OBJECTIVE: To study the biological function of phosphatidylcholine in bacteria, the borrelial pcs gene was inserted into ptac85 plasmid. Then E. coli Top10 pcs+ was constructed via the transformation of the recombinant plasmid. Phosphatidylcholine (30%) in total phospholipids was achieved when the bacterial cells were incubated in Luria-Bertani (LB) medium supplemented with 1% choline and induced by 0.5 mmol/L isopropy-beta-D-thiogalactoside (IPTG) for 4-8 hours at 37 degrees C. METHODS: Ampicillin inhibitionof E. coli Top10 pcs+ was tested at first, and then beta-lactamase activity in periplasm was examined. Finally Western blot was used to detect the amount of beta-lactamase in both bacterial periplasm and cytoplasm. RESULTS: Antibiotic tests showed that high concentrations of ampicillin inhibited the growth of E. coli Top100 pcs+ with an IC50 of 70-800 microg/mL. Active assays revealed that the beta-lactamase activity in periplasm was only 1/5 of that for the control strain E. coli Top10/p(tac)85. Western blotting confirmed that the low activity of beta-lactamase in E. coli Top10 pcs+ resulted from a lower amount of beta-lactamase in its periplasm. CONCLUSION: Our results demonstrated that the phospatidylcholine incorporated into bacterial membrane retarded secretion of Escherichia coli penicillin beta-lactamase from cytoplasm into periplasm, which suggested that phosphatidylcholine might play a role in the regulation of protein secretion in those bacteria able to synthesize phosphatidylcholine.
[Safety assessment of starters culture bacteria in fermented milk in China]
Wei Sheng Yan Jiu. 2008 Mar; 37(2): 193-5
Xu J, Yan W, Yang B, Li Z
In this study, we analysised the safety of 137 strains of starters culture bacteria in fermented milk between 2000 and 2006 in China. The study was designed to evaluate the acute oral toxicity of 137 strains to mice, and 31 of 137 strains for Minimum inhibitory concentrations (MIC) of 20 kinds of antibiotics by broth micro-dilution method. The result indicated that except a strain of Lactobacillus rhamnosus, other probiotics were non-pathogenic and safe for human consumption. 31 strains of probiotics were sensitive to Ampicillin, Penicillin, Imipenem, Gentamicine, Amoxicillin, Amoxicillin/clavulanic acid, Gatifloxacin, Erythromycin, Clindamycin, and were resistant to Nalidixic acid, Vancomycine, Fosfomycin.
[Analysis of antibiotic susceptibility of foodborne Listeria monocytogenes in China]
Wei Sheng Yan Jiu. 2008 Mar; 37(2): 183-6
Yang Y, Fu P, Guo Y, Liu X
OBJECTIVE: To study the antibiotic susceptibility of foodborne Listeria monocytogenes in China. METHODS: The susceptibilities of 476 strains of foodborne Listeria monocytogenes to antibiotics were determined in Broth Microdilution Susceptibility Testing in Clinical and Laboratory Standards Institute. The antibiotics of gentamicin, ampicillin, penicillin, tetracycline, doxycycline, imipenem, erythromycin, ciprofloxacin, levofloxacin, cephalothin, rifampin, vancomycin, chloramphenicol, Trimethoprim-sulfamethoxazole, ampicillin-sulbactam were used. RESULTS: The rates of antibiotic resistance in 467 is olates were 4.5%. Tetracycline resistance was most prevalent, accouting for 4.07% . The foods that the rates of antibiotic resistance were highest were vegetable (10%). Among 14 provinces, Jilin, Hubei and Hebei were the third top, the rate of which were 19.6% and 9.1% and 8%, respectively. CONCLUSION: It was suggested that antibiotic resistance exists in foodborne Listeria monocytogenes to a certain extent in China. It should pay more attention to the use of drugs in prevention and clinic treatment to reduce the antibiotic resistant strains.
Appl Environ Microbiol. 2008 Jun 27;
Los JM, Golec P, Wegrzyn G, Wegrzyn A, Los M
The use of low concentrations (optimally 2.5 - 3.5 microg/ml, depending on top agar thickness) of ampicillin in the bottom agar of the plate allows for formation of well-visible plaques of bacteriophages which otherwise form extremely small or no plaques on Escherichia coli lawns. Using this method we were able to obtain plaques of newly isolated bacteriophages, propagated after induction of prophages present in six E. coli O157:H(-) strains, which did not form plaques when employing standard plating procedures.
Vet Microbiol. 2008 May 24;
Sharma VK, Stanton TB
Enterohemorrhagic Escherichia coli (EHEC) O157:H7 (strain 86-24) harbors a 3.3-kb plasmid (pSP70) that does not encode a selectable phenotype. A 1.1-kb fragment of DNA encoding kanamycin resistance (Kan(r)) was inserted by in vitro transposon mutagenesis at a random location on pSP70 to construct pSP70-Kan(r) that conferred Kan(r) to the host E. coli strain. Oligonucleotides complementary to 5' and 3' ends of the fragment encoding Kan(r) were used for initiating nucleotide sequencing from the plus and minus strands of pSP70, and thereafter primer walking was used to determine nucleotide sequence of pSP70. Analysis of nucleotide sequence revealed that pSP70 contained 3306 base pairs in its genome and that the genome was almost 100% identical to nucleotide sequences of small plasmids identified in EHEC O157:H7 isolates from Germany and Japan. A DNA cassette encoding a green fluorescent protein (GFP), ampicillin resistance (Amp(r)), and a double transcriptional terminator (DT) was cloned in pSP70 either at the BamHI site (created by deletion of mobA by PCR) or at the NsiI site located downstream of mobA to generate pSP70 DeltamobA-GFP/Amp(r)/DT (pSM431) and pSP70-GFP/Amp(r)/DT (pSM433), respectively. Introduction of pSM431 or pSM433 into EHEC O157:H7 yielded ampicillin-resistant colonies that glowed green under UV illumination. Consecutive subcultures of EHEC O157:H7, carrying pSM431 or pSM433 under conditions simulating the environment of bovine intestine (no selective antibiotic, incubation temperature of 39 degrees C, with or without oxygen), demonstrated that these plasmids were highly stable as greater than 95% of the isolates recovered from these subcultures were positive for green fluorescence. These findings indicate that EHEC O157:H7 carrying pSM431 or pSM433 would be useful for studying persistence and shedding of this important food-borne pathogen in cattle.
J Microbiol Methods. 2008 Jun 26;
Lestari ES, Severin JA, Filius PM, Kuntaman K, Offra Duerink D, Hadi U, Wahjono H, Verbrugh HA,
Although a variety of techniques are available for antimicrobial susceptibility testing, disk diffusion methods remain the most widely used. We compared the accuracy of disk diffusion zone diameters as obtained by manual zone measurements in a low resource country (Indonesia) to that by automated zone measurements (Oxoid aura image system) in a high resource setting (the Netherlands) to determine susceptibility categories (sensitive, intermediate susceptible or resistant). A total of 683 isolates were studied, including 294 Staphylococcus aureus, 195 Escherichia coli and 194 other Enterobacteriaceae. Antimicrobial agents included tetracycline, oxacillin, gentamicin, erythromycin, trimethoprim/sulfamethoxazole and chloramphenicol for S. aureus and ampicillin, gentamicin, cefotaxime, ciprofloxacin, trimethoprim/sulfamethoxazole, and chloramphenicol for E. coli and other Enterobacteriaceae. Of the 4098 drug-organism combinations, overall category agreement (CA), major discrepancy (MD) and minor discrepancy (mD) between the two methods were 82.4% (3379/4098), 6.0% (244/4098) and 11.6% (475/4098), respectively. One hundred and sixty three of 244 MDs were resolved using reference broth microdilution method. Overall very major error (VME), major error (ME) and minor error (mE) of manual zone measurement were 28.8%, 45.4% and 4.9%, respectively and for the aura image system 4.9%, 16.0% and 4.9%, respectively. The results of this study indicate that the disk diffusion method with manual zone measurement in Indonesia is reliable for susceptibility testing. The use of an automated zone reader, such as the aura image system, will reduce the number of errors, and thus improve the accuracy of susceptibility test results for medically relevant bacteria.
Talanta. 2008 Jun 15; 75(5): 1253-9
Duan H, Liu Z, Liu S, Yi A
Under the HCl solution and heating condition, penicillin antibiotics such as amoxicillin (AMO), ampicillin (AMP), sodium cloxacillin (CLO), sodium carbenicillin (CAR) and sodium benzylpenicillin (BEN) could react with Fe(III) to produce Fe(II) which further reacted with Fe(CN)(6)(3-) to form a Fe(3)[Fe(CN)(6)](2) complex. By virtue of hydrophobic force and Van der Waals force, the complex aggregated to form Fe(3)[Fe(CN)(6)](2) nanoparticles with an average diameter of 45 nm. This resulted in a significant enhancement of resonance Rayleigh scattering (RRS) and non-linear scattering such as second-order scattering (SOS) and frequency doubling scattering (FDS). The increments of scattering intensity (DeltaI) were directly proportional to the concentrations of the antibiotics in a certain range. The detection limits for the five penicillin antibiotics were 2.9-6.1 ng ml(-1) for RRS method, 4.0-6.8 ng ml(-1) for SOS method and 7.4-16.2 ng ml(-1) for FDS method, respectively. Among them, the RRS method exhibited the highest sensitivity and the AMO system was more sensitive than other antibiotics systems. Based on the above researches, a new highly sensitive and simple method for the indirect determination of penicillin antibiotics has been developed. It can be applied to the determination of penicillin antibiotics in capsule, tablet, human serum and urine samples. In this work, the spectral characteristics of absorption, RRS, SOS and FDS spectra, the optimum conditions of the reaction and the influencing factors were investigated. In addition, the reaction mechanism was discussed.