OBJECTIVE: This study aimed to demonstrate that apoptosis in Plasmodium falciparum can be measured using kits originally designed for mammalian cells. The antimalarial chloroquine and antibiotics tigecycline and telithromycin were used to show the performance of the assays.

METHODS: Nuclear stain DAPI fluorescence was used to estimate cytotoxicity. Apoptotic assays used were: CaspaTag™ for caspase activation, acridine orange for nuclear condensation, and TUNEL for DNA fragmentation.

RESULTS: The IC50 values (95% confidence interval) for telithromycin (TL), tigecycline (TG) and chloroquine (CQ) were found to be 1.00 (0.47-1.53) µM, 4.56 (2.32-6.80) µM, and 0.019 (0.0089-0.029) µM, respectively. Activated caspase-like molecules seemed to be present in all erythrocytic stages, appearing to rise and fall with cell cycle progression with drug exposure appearing to dysregulate this pattern. Nuclear condensation and DNA fragmentation occurred late in the untreated erythrocytic life cycle of the parasite but were advanced by drug exposure.

CONCLUSION: The study shows that drug-induced apoptosis can be measured in Plasmodium falciparum using the methods. These assays could be used for drug discovery, in particular, using high throughput flow cytometry.

Animal ; Chloroquine ; Antimalarials ; Plasmodium Falciparum ; Telithromycin ; Parasites ; Tigecycline ; Dna Fragmentation ; Apoptosis ; Dapi ; Ketolides ; Minocycline ; Erythrocytes

The in vitro antibacterial activities of oral cephem antibiotics and ketolide telithromycin against major respiratory pathogens possessing beta-lactam-resistant mutations (within the pbp gene) and/or macrolide-resistant genes (erm and mef) were examined in clinical isolates collected at 66 institutes in all over the Japan between 2002 and 2003. Telithromycin showed the strongest antibacterial activity against methicillinsusceptible Staphylococcus aureus strains with and without macrolide-resistant genes, such as ermA or ermC gene. All the cephem antibiotics showed potent antibacterial activity against Streptococcus pyogenes, with minimum inhibitory concentrations (MICs) of 0.015 mg/L or lower. Cefdinir had a much higher MIC90 against genotypic penicillin-resistant Streptococcus pneumoniae (gPRSP) than cefditoren and cefcapene (8 mg/L cefdinir vs. 1 mg/L cefditoren and cefcapene). The majority of gPRSP harbored either ermB or mefA, and the antibacterial activity of telithromycin against these strains was decreased however some susceptibility was still sustained. Cefditoren exerted the strongest antibacterial activity against beta-lactamase-negative ampicillin-resistant Haemophilus influenzae, with an MIC90 of 0.5 mg/L. These results underline the importance of checking the susceptibility and selecting an appropriate antibiotic against target pathogens.
Streptococcus pyogenes/*drug effects ; Streptococcus pneumoniae/*drug effects ; Staphylococcus aureus/*drug effects ; Microbial Sensitivity Tests ; Methicillin Resistance ; Ketolides/*pharmacology ; Humans ; Haemophilus influenzae/*drug effects ; Cephalosporins/*pharmacology ; Administration, Oral

Genetic engineering on macrolide antibiotics was a new field in recent years and more than 100 novel polyketides had been produced until then. Using genomic DNA of S. erythraea A226 as a template, about 3.2 kb DNA fragment without KR6 domain was amplified by overlapping PCR technique and cloned into pWHM3 carrier, which resulted in the construction of homologous recombinant plasmid pWHM2201. Plasmid pWHM2201 was introduced into protoplasts of S. erythraea A226 by PEG-mediated transformation and integrated into the gene locus for erythromycin biosynthesis. After integrants grew for two generations on R3M media without Tsr, they were protoplasted and grown on R3M plates. By PCR identification, 8 mutants without KR6 domain were selected out and named S. erythraea M(1-8). With the identification of mass spectrometry, it was proved that S. erythraea M1 synthesized a novel ketolide compound 3-deoxy-3-oxo-erythronolide B.
Anti-Bacterial Agents ; biosynthesis ; chemistry ; Chromosomes, Bacterial ; Erythromycin ; analogs & derivatives ; biosynthesis ; chemistry ; Genetic Engineering ; Ketolides ; Molecular Structure ; Multienzyme Complexes ; genetics ; Saccharopolyspora ; enzymology ; genetics ; metabolism

Drug-resistance has become a challenging clinical problem. Ketolides, a new class of erythromycin derivatives, have shown promising effectiveness in killing drug-resistant bacteria. This article reviews recent development in synthesis of ketolides, with focus on the modification and synthesis of some important positions on erythromycin A cycles.
Animals ; Anti-Bacterial Agents ; chemical synthesis ; chemistry ; pharmacology ; Drug Resistance, Bacterial ; Erythromycin ; analogs & derivatives ; chemical synthesis ; pharmacology ; Humans ; Ketolides ; chemical synthesis ; chemistry ; pharmacology ; Macrolides ; chemical synthesis

BACKGROUNDThe emergence of bacterial resistance to commonly used antibiotics, such as macrolides, is complicating the management of respiratory tract infections (RTIs). Telithromycin, a ketolide antimicrobial structurally related to macrolides, is approved for the treatment of community-acquired RTIs, and shows lower pathogen resistance rates. The purpose of this study was to compare the efficacy and safety of telithromycin with clarithromycin, a macrolide routinely used as therapy for RTIs.

METHODSWe performed a meta-analysis of relevant randomized-controlled trials (RCTs) identified in PubMed, the Cochrane Library, Embase, CNKI and VIP databases. The primary efficacy outcome was clinical treatment success assessed at the test-of-cure time in the per-protocol population, and the primary safety outcome was drug related adverse effects.

RESULTSSeven RCTs, involving 2845 patients with RTIs, were included in the meta-analysis. Oral telithromycin and clarithromycin showed a similar clinical treatment success in modified intention to treat and per-protocol population (cure and improvement) (odds ratios (ORs): 0.84, 95% confidence intervals (CI): 0.64 - 1.11 and OR: 1.14, 95%CI: 0.71 - 1.85, respectively). Similar findings were obtained for secondary efficacy outcomes: clinical treatment success at a late post-therapy visit (OR: 0.92, 95%CI: 0.57 - 1.48) and microbiological treatment success at the test-of-cure time (OR: 1.14; 95%CI: 0.71 - 1.85). The safety outcome analysis indicated telithromycin had a similar risk of drug-related adverse effect and serious adverse effect with clarithromycin.

CONCLUSIONSOur findings indicate that oral telithromycin and clarithromycin have similar treatment efficacy and adverse effect. The advantages of lower antimicrobial resistance rates, once-daily short-duration dosing and reported lower health-care costs make oral telithromycin a useful option for the empiric management of mild-to-moderate RTIs.

Anti-Bacterial Agents ; therapeutic use ; Clarithromycin ; adverse effects ; therapeutic use ; Community-Acquired Infections ; drug therapy ; Humans ; Ketolides ; adverse effects ; therapeutic use ; Randomized Controlled Trials as Topic ; Respiratory Tract Infections ; drug therapy

BACKGROUND: The purpose of this study was to investigate perception of hand hygiene and actual hand washing practices of people who used public facilities as well as the presence of indicator bacteria and food-borne pathogens on their hands. Data from this study will be used as a tool for public education and provide basic information on the potential risk for the spread of infectious disease by hands. MATERIALS AND METHODS: Sixty S. aureus and 15 methicillin-resistant S. aureus (MRSA) were recovered from 500 swab samples from hands of people in public places, including super markets and amusement facilities in Gwangju Metropolitan City during February to May 2011. Using conventional methods and the Vitek system, all of the isolates were confirmed as Staphylococcus auerus (S. aureus). Antimicrobial susceptibility was determined by performing disk diffusion testing according to the Clinical Laboratory Standard Institute guidelines. The minimum inhibition concentrations (MICs) of MRSA isolates were tested using E-test strips. To confirm the MRSA, polymerase chain reaction (PCR) for the S. aureus-specific gene and mecA gene was performed. Gene detection using PCR, SCCmec typing, Panton-Valentine Leukocidin (PVL), and Multilocus sequence typing (MLST) were performed on all isolates of MRSA. RESULTS: Of 60 S. aureus isolates, 48 (80%) harbored at least one type of enterotoxin gene: two, three, four, and five types of enterotoxin gene were found in 16 (26.7%), seven (11.7%), 10 (16.7%), and eight (13.3%) isolates, respectively. The most prevalent antimicrobial resistance observed in the S. aureus isolates was to penicillin (92%, 55/60), followed by erythromycin (35%, 21/60), oxacillin (32%, 19/60), and ampicillin (23%, 14/60). No resistance was observed against vancomycin, clindamycin, linazolid, rifampin, imipenem, trimethoprim/sulfamethoxazole, and telithromycin. In this study, based on molecular characterization of MRSA isolates, all MRSA, except for one isolate, belonged to ST72 and SCCmec type IV. Eleven of 15 (78.6%) MRSA were ST72:SCCmecIV:t324. CONCLUSIONS: In this study, we detected serious pathogens, including S. aureus and MRSA, from swab samples of peoples' hands. Most S. aureus isolates harbored the enterotoxin gene and the types of MRSA isolated in this study were community-associated MRSA, indicating the importance of washing hands for public health.
Adenosine ; Ampicillin ; Bacteria ; Bacterial Toxins ; Clindamycin ; Communicable Diseases ; Diffusion ; Enterotoxins ; Erythromycin ; Exotoxins ; Hand ; Hand Disinfection ; Hand Hygiene ; Imipenem ; Ketolides ; Leukocidins ; Methicillin Resistance ; Methicillin-Resistant Staphylococcus aureus ; Multilocus Sequence Typing ; Oxacillin ; Penicillins ; Polymerase Chain Reaction ; Public Facilities ; Public Health ; Rifampin ; Staphylococcus ; Staphylococcus aureus ; Vancomycin