We have purified five types of lectins, named tachylectins, from circulating hemocytes and hemolymph plasma of the Japanese horseshoe crab, Tachypleus tridentatus. Tachylectin-1 interacts with Gram-negative bacteria probably through 2-keto-3-deoxyoctonate, one of the constituents of lipopolysaccharides (LPS). Tachylectin-1 also binds to polysaccharides such as agarose and dextran with broad specificity. Tachylectin-2 binds to D-GlcNAc or D-GalNAc and recognizes staphylococcal lipoteichoic acids and LPS from several Gram-negative bacteria. In contrast, tachylectins-3 and -4 specifically bind to S-type LPS from several Gram-negative bacteria through a certain sugar moiety on the O-specific polysaccharides (O-antigens). Tachylectin-5 identified in hemolymph plasma has the strongest bacterial agglutinating activity in the five types of tachylectins, and exhibits broad specificity against acetyl group-containing substances. Thus, the innate immune system of horseshoe crab may recognize invading pathogens through a combinatorial method using lectins with different specificities against carbohydrates exposed on pathogens. An encounter of these lectins derived from hemocytes and hemolymph plasma at injured sites, in response to the stimulation of LPS, suggests that they serve synergistically to accomplish an effective host defense against invading microbes and foreign substances.

Animals↗

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Sensitivity of Staphylococcus aureus, isolated from skin infections in 1994, to 19 antimicrobial agents.

The most common pathogen causing skin infections is Staphylococcus aureus and the incidence of multiply resistant strains of S. aureus has been increasing. The in vitro susceptibility of 130 isolates of S. aureus to 19 antimicrobial agents: ampicillin (ABPC), methicillin, cefaclor, cefpodoxime proxetil, gentamicin, erythromycin, clindamycin, minocycline, vancomycin, fusidic acid, norfloxacin, ofloxacin, enoxacin, ciprofloxacin, lomefloxacin, tosufloxacin, sparfloxacin, nadifloxacin and grepafloxacin, was evaluated by agar dilution tests. The S. aureus isolates were isolated from 130 patients with skin infections in 1994. The proportion of methicillin-resistant S. aureus isolates among the strains isolated was 19.2%. The concentration needed to inhibit 50% of the isolates was 3.13 mg/ml or less for all of the drugs, but the concentration needed to inhibit 90% of isolates was over 12.5 micrograms/ml, except in the cases of minocycline, vancomycin, fusidic acid, tosufloxacin and nadifloxacin. Tosufloxacin and nadifloxacin had the lowest minimum inhibitory concentrations. None of the S. aureus strains was resistant to nadifloxacin.

Anti-Bacterial Agents↗

PubMedDate not supplied

Activity of nadifloxacin against methicillin-resistant Staphylococcus aureus isolated from skin infections: comparative study with seven other fluoroquinolones.

The in vitro susceptibility of methicillin-resistant Staphylococcus aureus (MRSA) to nadifloxacin and seven other fluoroquinolones (norfloxacin, ofloxacin, enoxacin, ciprofloxacin, lomefloxacin, tosufloxacin and sparfloxacin) was evaluated. The MRSA isolates were isolated from 114 skin infections between 1991 and 1994. Nadifloxacin exhibited the lowest minimum inhibitory concentration and there were no MRSA isolates resistant to nadifloxacin, while there were some resistant to all of the other seven fluoroquinolones. The minimum concentrations of these drugs needed to cause 50% inhibition of the isolates increased dramatically from 1991 to 1992, but has hardly changed since 1992.

Anti-Infective Agents↗

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Sensitivity of Propionibacterium acnes isolated from acne patients: comparative study of antimicrobial agents.

The antimicrobial susceptibility of Propionibacterium acnes isolated before and after treatment of acne patients was measured. The four female and three male acne patients were treated with an oral acne medication, roxithromycin or minocycline, and/or a topical acne medication, nadifloxacin cream or clindamycin hydrochloride lotion for 1-8 weeks. The isolated strains were tested for their susceptibility to the antimicrobial action of: nadifloxacin, ofloxacin, erythromycin, clindamycin hydrochloride, tetracycline hydrochloride, minocycline, doxycycline, ampicillin, cephalexin and gentamycin. No resistant strains of P. acnes were observed.

Acne Vulgaris↗

PubMedDate not supplied

Sensitivity to antibacterials of Staphylococcus aureus isolated from different types of skin infections.

We examined the antibacterial susceptibility of Staphylococcus aureus isolated from several types of skin infections, which were classified into four groups: (i) impetigo, (ii) folliculitis, (iii) atopic dermatitis and eczema and (iv) ulcers and decubitus. The 50% minimal inhibitory concentration (MIC50) of the antibacterial agents was 3.13 micrograms/ml or lower, except that of gentamicin with isolates from the impetigo groups (25 micrograms/ml). The MIC90 of gentamicin was 50 micrograms/ml or more for isolates from all four groups. The isolates from the ulcers and decubitus group showed multiple resistance against antibacterial agents. The frequency of methicillin-resistant S. aureus was low, but was highest, at 25%, in the isolates from the ulcers and decubitus group. Few isolates from the atopic dermatitis and eczema group were resistant, and there was little difference in antibacterial resistance between isolates from atopic dermatitis and eczema.

Anti-Bacterial Agents↗

PubMedDate not supplied

Sensitivity to antibacterials of Staphylococcus aureus isolated from skin infections: a comparison of two hospitals.

We compared the sensitivities to antibacterials of Staphylococcus aureus strains isolated from skin infections in two hospitals of different sizes. There were differences between the two hospitals in the proportions of the strains isolated that were resistant to certain drugs, and these differences may be related to the patterns of drug use at each hospital. The differences in the patterns of drug use at each hospital may be due to the types of infections encountered and/or the ages of the patients, both of which differed greatly. The proportions of resistant strains may also be related to differences in the proportions of in-patients.

Anti-Bacterial Agents↗

PubMedDate not supplied

cDNA cloning, tissue distribution, and subcellular localization of horseshoe crab big defensin.

A full-length cDNA for horseshoe crab big defensin with a strong antimicrobial activity was obtained from a hemocyte cDNA library. The open reading frame of the cDNA coded for an NH2-terminal signal sequence followed by a propeptide and the mature big defensin. The propeptide is linked to the mature protein through an -Arg-X-Lys/Arg-Arg- motif, the processing site for Kex2-like proteases. Northern blot analysis revealed that big defensin is expressed in all the tissues tested, suggesting that big defensin plays an important role not only in hemocytes but also in other tissues for host defense. The subcellular localization, determined by immunocytochemistry at ultrastructural level, confirmed the previous findings obtained by biochemical analysis that big defensin locates in both small and large granules in hemocytes. Big defensin is the first example to demonstrate the existence of broad tissue distribution in horseshoe crab.

Amino Acid Sequence↗