Comparative Evaluation of the Cytotoxic and Angiogenic Effects of Minocycline and Clindamycin: An In Vitro Study.

INTRODUCTION: This study aimed to compare the cytocompatibility and angiogenic potential of 2 antibiotics (clindamycin [CLIN] and minocycline [MINO]) at distinct concentrations on dental pulp stem cells (DPSCs) and human umbilical vein endothelial cells (HUVECs). METHODS: DPSCs and HUVECs were exposed to cell culture media modified with CLIN or MINO at concentrations ranging from 30 µg/mL-1000 µg/mL. Cell toxicity and proliferation were investigated using the lactate dehydrogenase and tetrazolium reduction assays, respectively. A capillarylike tube formation in vitro assay was conducted to determine the angiogenic potential associated with each antibiotic. Additionally, selected morphometric angiogenesis parameters were determined using dedicated software (WimTube; Onimagin Technologies SCA, Córdoba, Spain). All statistical analyses were performed using 1-way analysis of variance and the Tukey post hoc test (α= .05). RESULTS: The collected data showed that compared with the control (cell culture media, alpha-minimum essential medium Eagle) increasing the antibiotic concentration significantly decreased cell viability and proliferation of both DPSCs and HUVECs. In terms of angiogenic potential, when tested at 30 µg/mL and 50 µg/mL, CLIN significantly amplified tube formation when compared with MINO with angiogenesis parameters (ie, tube length and tube number) similar to the effect promoted by exogenous vascular endothelial growth factor (50 ng/mL). CONCLUSIONS: CLIN was less cytotoxic when compared with MINO at higher concentrations. Of note, CLIN did not hinder the proangiogenic activity induced by vascular endothelial growth factor to the same extent as MINO, suggesting that the replacement of MINO by CLIN might translate into positive implications in the overall regenerative outcome.

Effects of a synbiotic on the fecal microbiome and metabolomic profiles of healthy research cats administered clindamycin: a randomized, controlled trial.

Reduction in antibiotic-associated gastrointestinal signs (AAGS) in people co-administered probiotics is believed to result from shifts in the microbiome and metabolome. Amelioration of AAGS in cats secondary to synbiotic administration has recently been demonstrated. Thus, the aim of this randomized, double-blinded, placebo-controlled trial was to characterize associated changes in the fecal microbiome and metabolome. Sixteen healthy research cats received clindamycin with food, followed 1 h later by either a placebo or synbiotic, daily for 21 days. Fecal samples were collected during baseline, antibiotic administration, and 6 weeks after antibiotic discontinuation. Sequencing of 16S rRNA genes was performed, and mass spectrometry was used to determine fecal metabolomic profiles. Results were compared using mixed-model analyses, with P < 0.05 considered significant. Alpha and beta diversity were altered significantly during treatment, with persistent changes in the Shannon and dysbiosis indices. The relative abundance of Actinobacteria (Adlercreutzia, Bifidobacterium, Collinsella, Slackia), Bacteroidia (Bacteroides, Prevotella), Ruminococcaceae (Faecalibacterium, Ruminococcus), Veillonellaceae (Megamonas, Megasphaera, Phascolarctobacterium) and Erysipelotrichaceae ([Eubacterium]) decreased and relative abundance of Clostridiaceae (Clostridium) and Proteobacteria (Enterobacteriaceae) increased during treatment, followed by variable return to baseline relative abundances. Derangements in short-chain fatty acid (SCFA), bile acid, tryptophan, sphingolipid, polyamine, benzoic acid, and cinnaminic acid pathways occurred with significant group by time, group, and time interactions for 10, 5, and 106 metabolites, respectively. Of particular note were changes related to polyamine synthesis. Further investigation is warranted to elucidate the role of these alterations in prevention of AAGS in cats, people, and other animals treated with synbiotics.

Therapeutic effects of probiotics on neurotoxicity induced by clindamycin and propionic acid in juvenile hamsters.

The present study investigated the therapeutic effects of probiotics on brain intoxication induced by clindamycin and propionic acid (PPA) in hamsters. Fifty golden Syrian hamsters were randomly divided into five experimental groups of ten animals each: (A) control group receiving phosphate buffered saline; (B) oral buffered PPA-treated group being administered with a neurotoxic dose of 250 mg/kg PPA during three days; (C) oral clindamycin-treated group receiving a single dose of 30 mg clindamycin/kg; and (D, E) the two therapeutic groups being administered the same doses of clindamycin and PPA followed by probiotics for three weeks at a daily dose of 0.2 g/kg. Biochemical parameters of energy metabolism and oxidative stress were examined in brain homogenates from all hamsters. The development of pathogenic bacteria was monitored on stool samples from all hamsters. Descriptive changes in fecal microbiota and overgrowth of Clostridium species in clindamycin and PPA treated hamsters were recorded. Interestingly, probiotics were shown effective to restore normal gut microbiota. Clindamycin and PPA treatments caused an elevation in lipid peroxidation and catalase activity, as oxidative stress markers, together with a reduction in GST activity and GSH level. Energy metabolism impairment was ascertained via the activation of creatine kinase and a decrease of lactate dehydrogenase. These findings suggest that bacteria overgrowth caused by PPA and clindamycin was efficient to illustrate signs of neuronal toxicity. The present study indicates that probiotic treatment can improve poor detoxification, oxidative stress, and altered gut microbiota as mechanisms implicated in the etiology of many neurological disorders.

Safety of intravitreal clindamycin in albino rabbit eyes.

PURPOSE: To study the potential toxic effects of intravitreal clindamycin on the retina of albino rabbits, by assessing functional and morphological retinal changes. METHODS: Eight albino rabbits were included in the study. In each rabbit, 1 mg/0.1 ml clindamycin was injected into the vitreous of the right (experimental) eye, and 0.1 ml saline was injected into the vitreous of the left (control) eye. The electroretinogram (ERG) was recorded before injection, 3 days, 1, 2, and 4 weeks post-injection. The visual evoked potential (VEP) was recorded 4 weeks post-injection. Clinical examination was conducted at all time points. The eyes were enucleated at the termination of the follow-up period in order to prepare the retinas for histology in order to assess retinal structure. RESULTS: ERG and VEP responses that were recorded from the experimental eye at different times following intravitreal clindamycin injection were very similar to the corresponding responses that were recorded from the control eyes. Clinical examination was normal in all eyes, and no histological damage was observed. CONCLUSIONS: Intravitreal injection of 1 mg clindamycin does not cause functional or morphological signs of retinal toxicity in albino rabbits, during a period of 4 weeks post-injection. These findings support the clinical use of 1 mg intravitreal clindamycin.

Teratogenicity of Artemether-Clindamycin Nanostructured Lipid Carriers in Rats.

Currently, artemisinin-based combination therapy is considered the best option in the treatment of malaria. However, toxicity of artemisinins limits their use in pregnancy. In the absence of sufficient toxicity data, the World Health Organization recommends that artemisinins are not to be used in the first trimester of pregnancy and can be used only in second and third trimesters, when other treatments are not available. We have recently observed that drugs loaded in nanolipid carriers are selectively taken up in Plasmodium-infected erythrocytes with a concomitant reduction in the dose required to cure animals. Thus, 20% of the therapeutic dose of artemether-clindamycin (ARM-CP) loaded in nanostructured lipid carriers (NLCs; mean particle size 55 ± 10 nm) resulted in complete parasite clearance and 100% survival of infected mice. Here, we investigate the teratogenicity of this formulation in rodents (dosing on alternate days from 6th day to 18th day of gestation; 12-15 animals/group). The teratogenicity of drug-free NLCs and artesunate-clindamycin (ARS-CP) solution was also evaluated. We found that the therapeutic dose of ARS-CP caused fetal resorptions (87.5% resorptions in 8 litters), suggesting its unsuitability for use in pregnancy. Artesunate-clindamycin NLCs at therapeutic doses also resulted in ∼90% fetal resorptions in 10 litters examined. However, postimplantation losses or fetal malformations were not observed at the dose of ARM-CP NLCs that was required for complete parasite clearance in preclinical trials (ie, 20% of the therapeutic dose). Our data suggest that the NLCs loaded with 20% of the therapeutic dose of ARM-CP may have potential in treating malaria during pregnancy.

Effects of erythromycin, trimethoprim and clindamycin on attached microbial communities from an effluent dominated prairie stream.

In this study, differing metrics were utilized to measure effects of erythromycin (ER), trimethoprim (TR) and clindamycin (CL) on the structure and function of attached Wascana Creek, SK microbial communities. All three test antibiotics, especially ER, affected community structure and function of biofilms grown in rotating annular reactors. Biofilm thickness, bacterial biomass, and lectin binding biovolume (exopolymeric substances) were consistently less in ER treated biofilms when compared to the control. As well negative effects on protozoan numbers, and carbon utilization were detected. Finally, PCA analyses of DGGE results indicated that bacterial community diversity in ER exposed biofilms was always different from the control. ER exhibited toxic effects even at lower concentrations. Observations on TR and CL exposed biofilms indicated that bacterial biomass, lectin binding biovolume and carbon utilization were negatively affected as well. In terms of bacterial community diversity, however, CL exposed biofilms tended to group with the control while TR grouped with nutrient additions suggesting both nutritive and toxic effects. This study results represent an important step in understanding antibiotic effects, especially ER, on aquatic microbial communities. And because ER is so ubiquitous in receiving water bodies worldwide, the Wascana study results suggest the possibility of ecosystem disturbance elsewhere. CAPSULE ABSTRACT: Erythromycin (ER) is ubiquitous in waterbodies receiving sewage effluent. Structure and function of microbial communities from an effluent dominated stream were negatively affected by ER, at realistic concentrations.

Time- and concentration-dependent cytotoxicity of antibiotics used in endodontic therapy.

OBJECTIVE: New drugs have to be assessed in endodontic therapy due to the presence of microorganisms resistant to therapeutic procedures. Thus, this study evaluated the time- and concentration-dependent cytotoxicity of different antibiotics used in endodontic therapy. MATERIAL AND METHODS: Human gingival fibroblasts were treated and divided into the following experimental groups: Group I - control; Group II - ciprofloxacin hydrochloride; Group III - clyndamicin hydrochloride; and Group IV - metronidazole. Each drug was used at concentrations of 5, 50, 150, and 300 mg/L for 24, 48, 72, and 96 h. Cytotoxicity was evaluated by the MTT assay [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] and spectrophotometric reading of ELISA plates. The results were analyzed by BioEstat 4.0 software using Kruskal-Wallis and Dunn's tests at a significance level of 5%. Cell viability was assessed for the different concentrations and times. RESULTS: All drugs presented dose-dependent cytotoxicity. Concentrations of 5 and 50 mg/L produced viable fibroblasts at all experimental times in all groups. CONCLUSIONS: Cell viability at 24 h was greater than in the other experimental times. Comparison between the same concentrations of antibiotics at different times showed that metronidazole presented the highest cell viability at 72 and 96 h compared to the other antibiotics, whereas clyndamicin hydrochloride showed higher cell viability at 72 h than ciprofloxacin hydrochloride.

Time- and concentration-dependent cytotoxicity of antibiotics used in endodontic therapy

OBJECTIVE: New drugs have to be assessed in endodontic therapy due to the presence of microorganisms resistant to therapeutic procedures. Thus, this study evaluated the time- and concentration-dependent cytotoxicity of different antibiotics used in endodontic therapy. MATERIAL AND METHODS: Human gingival fibroblasts were treated and divided into the following experimental groups: Group I - control; Group II - ciprofoxacin hydrochloride; Group III - clyndamicin hydrochloride; and Group IV - metronidazole. Each drug was used at concentrations of 5, 50, 150, and 300 mg/L for 24, 48, 72, and 96 h. Cytotoxicity was evaluated by the MTT assay [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] and spectrophotometric reading of ELISA plates. The results were analyzed by BioEstat 4.0 software using Kruskal-Wallis and Dunn's tests at a signifcance level of 5 percent. Cell viability was assessed for the different concentrations and times. RESULTS: All drugs presented dose-dependent cytotoxicity. Concentrations of 5 and 50 mgjL produced viable fibroblasts at all experimental times in all groups. CONCLUSIONS: Cell viability at 24 h was greater than in the other experimental times. Comparison between the same concentrations of antibiotics at different times showed that metronidazole presented the highest cell viability at 72 and 96 h compared to the other antibiotics, whereas clyndamicin hydrochloride showed higher cell viability at 72 h than ciprofoxacin hydrochloride.

Design and in vitro evaluation of a novel bioadhesive vaginal drug delivery system for clindamycin phosphate.

To develop more effective treatment for bacterial vaginosis, bioadhesive film formulations of clindamycin phosphate (CL) for vaginal delivery were studied. The bioadhesive films were prepared by solvent evaporation method. A 3(2) full factorial design was utilized for optimization of the effect of independent variables such as amount of hydroxypropyl cellulose (X1), amount of xanthan gum (X2) on mechanical properties, and % drug retained on vaginal mucosa. The films were evaluated for various aesthetic and physicodynamic properties. Batch F(86) showed highest overall desirability of 0.99. Batch F86 was considered optimal composition for a novel bioadhesive vaginal formulation, as they have good peelability, high % elongation at break, moderate tensile strength, and retained on vaginal mucosa up to 8 h. Also, films were non-cytotoxic as indicated by negligible decrease in cell viability. Our study may provide a potential vaginal delivery system of CL against bacterial vaginosis.

Photocarcinogenesis and toxicity of benzoyl peroxide in hairless mice after simulated solar radiation.

Topical benzoyl peroxide (BPO) gel has long been used to treat acne vulgaris and has recently been combined with clindamycin (BPO-clin). No skin malignancies have been reported after clinical use of BPO, but there has been concern about the possible carcinogenicity of BPO alone and in combination with UV radiation. BPO can promote skin tumorigenesis in a mouse skin chemical carcinogenesis model. As acne vulgaris is frequently localized on sun-exposed areas, we investigated whether BPO or BPO-clin accelerates photocarcinogenesis in combination with simulated solar radiation (SSR) in 12 groups of 25 hairless female C3.Cg/TifBomTac-immunocompetent mice. BPO or BPO-clin was applied topically to the back five times each week, followed by SSR three times each week (2, 3, or 4 standard erythema doses) 3-4 h later, for 365 days or until death. Generally BPO and BPO-clin did not accelerate the time to first, second or third tumor. Therefore, there is no evidence suggesting that BPO or BPO-clin is photocarcinogenic. However, we found significantly higher mortality in the SSR exposed groups receiving BPO and BPO-clin compared with groups receiving only BPO or BPO-clin. Our results show that BPO and the combination of BPO and clindamycin do not accelerate photocarcinogenesis, but are toxic in hairless mice. Based on the current data, the cancer risk associated with the use of BPO and BPO-clin in sun-exposed areas is minimal. Thus, while the carcinogenic potential of BPO is not fully understood, at the present time, evidence suggests that this compound is safe to use.

Differential toxicity of reactive metabolites of clindamycin and sulfonamides in HIV-infected cells: influence of HIV infection on clindamycin toxicity in vitro.

Hypersensitivity adverse drug reactions are much more common among patients with acquired immunodeficiency syndrome (AIDS) than in the general population. High rates of hypersensitivity reactions to clindamycin have been noted. To investigate the role of reactive metabolites in these reactions, the authors studied toxicity of clindamycin and sulphamethoxazole (SMX) and their metabolites in uninfected and human immunodeficiency virus (HIV)-infected MOLT3 cells. Infected and uninfected cells were incubated with clindamycin or sulphamethoxazole hydroxylamine in increasing concentrations; reactive metabolites were generated by coincubation of cells and drug with murine microsomes and a microsomal activating system. Over a concentration range of 0 to 400 microM SMX-HA, there was a significant concentration-dependent increase in cell death in HIV-infected compared to uninfected cells (28%+/-3% vs 8%+/-5% at 400 microM, P < .05). In contrast, coincubation of cells with clindamycin, microsomes, and a microsomal activating system, as well as combinations of primaquine or pyrimethamine, was not associated with an increase in cell death among infected compared to uninfected cells. No concentration-toxicity was demonstrated. These data support the role of reactive metabolites in adverse drug reactions to sulfonamides during HIV infection, whereas alternate mechanism(s) may be responsible for increased rates of adverse drug reactions to clindamycin among patients with AIDS.

Persistent acylation of high-molecular-weight penicillin-binding proteins by penicillin induces the postantibiotic effect in Streptococcus pyogenes.

Penicillin at 10X MIC induced a postantibiotic effect (PAE) of 2.1 h in Streptococcus pyogenes. Progressive increases in the densities of penicillin-binding proteins (PBPs) 1-3 of the bacterium were detected at 30, 60, and 90 min during the postantibiotic phase. The increase in colony-forming units during this phase paralleled the kinetics of incorporation of lysine into proteins, suggesting that growth was triggered by de novo synthesis of PBPs. The question was raised as to whether the progressive increases in densities of PBPs were due to the restoration of preexisting PBPs or to synthesis of new PBPs. With 10X MIC of clindamycin to inhibit PBP synthesis during the postantibiotic phase, the temporal increase in densities of PBPs 1-3 were totally inhibited. These results suggest that the PAE of penicillin in S. pyogenes is caused by irreversible binding of penicillin to PBPs 1-3 and represents the time necessary for synthesis of new PBPs required for normal growth.

[Study of general toxic and organotropic properties of clindamycin in long-term experiments]. / Izuchenie obshchetoksicheskikh i organotropnykh svoistv klindamitsina v khronicheskikh éksperimentakh.

The action of clindamycin monohydrate on the general state and weight rise, liver and kidney functions, peripheral blood count and pathomorphological state of the viscera was studied on rats in chronic experiments. Clindamycin was administered to laboratory animals orally in doses of 50, 100, 150 and 300 mg/kg. It was shown that some adverse reactions to the drug and in particular disorders in blood coagulation and morphological changes in the intestine did not depend on its dose and were due to duration of the drug use and probable development of dysbacteriosis. At the same time the disorders in the liver and kidney functions though transitory did depend, to a greater extent, on the dose and were evident after the antibiotic overdosage.

Effect of clindamycin on factor-VII activity in healthy cats.

Four healthy cats were given clindamycin orally in daily doses of 25 or 50 mg/kg of body weight for 6 weeks. Significant change in Factor-VII activity was not found, compared with pretreatment values. In 2 cats tested, toxin produced by Clostridium difficile was not detected in fecal samples obtained before treatment and at 6 weeks after treatment, suggesting that intestinal overgrowth by C difficile did not develop. Results of the study seemed to indicate that orally administered clindamycin does not measurably reduce synthesis of vitamin K-dependent clotting factors in healthy cats.

Effect of cefotetan in clindamycin-induced enterocolitis in hamsters.

In hamsters the administration of clindamycin provokes a fatal diarrhea and death in 1-2 days. This study was performed in order to assess the possible protective effect of three cephalosporins in clindamycin-induced enterocolitis in these laboratory animals. The efficacy of cefotetan was compared with that of cefoxitin and latamoxef: the hamsters were treated twice daily for 5 days with clindamycin (10 mg/kg) by oral route, and cefotetan, cefoxitin and latamoxef (100 mg/kg) were given subcutaneously. All animals developed "wet-tail syndrome", but cefotetan and latamoxef were able to protect a large percentage of hamsters from death and to prolong the survival time.

A comparison of Cleocin T 1 percent solution and Cleocin T 1 percent lotion in the treatment of acne vulgaris.

A randomized, investigator-blind study was conducted to compare the efficacy and skin tolerance of Cleocin T Topical 1 percent Solution and Cleocin T Topical 1 percent Lotion. Both treatments reduced acne lesion counts. More than 70 percent of the evaluable patients receiving each treatment reported that their acne improved by the end of the twelve-week study. Skin dryness was reported significantly more often by patients applying the solution than by those applying the lotion. This newly developed lotion formulation of topical clindamycin phosphate is equal in efficacy to, and appears to be less irritating than, Cleocin T Topical Solution.

Studies with temocillin in a hamster model of antibiotic-associated colitis.

Hamsters given the new penicillin temocillin, either orally or by injection, did not develop antibiotic-associated colitis, whereas animals given the control antibiotics cefoxitin or clindamycin developed the disease, which is characterized by marked hemorrhagic cecitis and high cecal levels of Clostridium difficile cytotoxin.

Characterization of Bacteroides ovatus plasmid pBI136 and structure of its clindamycin resistance region.

Genetic and physical analyses were used to characterize the Bacteroides ovatus R plasmid pBI136. Results from restriction endonuclease cleavage studies were used to construct a physical map of the plasmid for the enzymes EcoRI, BamHI, ClaI, XbaI, SalI, and SmaI. Based on the sizes of restriction fragments generated in these studies, the plasmid was estimated to be 80.6 kilobase pairs (kb). A 7.2-kb region of the plasmid required for resistance to lincosamide and macrolide (LM) antibiotics was mapped by analysis of spontaneously occurring LM-sensitive deletion derivatives. Hybridization studies showed that this region and an adjoining 2.9-kb EcoRI fragment were responsible for the previously reported homology among Bacteroides plasmids pBF4, pBFTM10, and pBI136. Within this region of homology, 0.5 kb was attributed to a directly repeated sequence thought to bound the LM resistance determinant on pBF4 and pBFTM10. Two pBI136 EcoRI fragments spanning the putative LM resistance region were cloned in Escherichia coli, and heteroduplex analysis of these recombinant plasmids revealed the presence of a 1.2-kb directly repeated sequence. These results suggested that the pBI136 LM resistance determinant resides on an 8.4-kb segment of DNA containing 6.0 kb of intervening DNA sequences bounded by a 1.2-kb directly repeated sequence.

Studies with temocillin in the hamster model of antibiotic-associated colitis.

The studies reported here were designed to ascertain whether or not the new beta-lactam antibiotic, temocillin, would produce antibiotic-associated colitis in the hamster. The experiments were controlled with clindamycin and cefoxitin, which are known to induce antibiotic-associated colitis experimentally and clinically. All three antibiotics were administered to groups of animals both parenterally and orally. Clindamycin, at 1 mg/hamster, caused a slow onset of antibiotic-associated colitis by both routes, with death occurring at between 4 and 8 days. 80 to 100% of the animals had diarrhoea and showed signs of haemorrhage and caecal distension, with the caecal contents being Clostridium difficile toxin-positive. The onset of antibiotic-associated colitis after administration of cefoxitin was less marked at the 1 mg parenteral dose, with only 40% of the hamsters showing signs of colitis. At the higher doses of cefoxitin, colitis was more severe and the animals exhibited dramatic weight loss, with death occurring at between 3 and 5 days. The majority of animals had diarrhoea and were C. difficile toxin-positive; 60 to 80% also showed signs of haemorrhage and caecal distension. In contrast, the hamsters receiving temocillin remained healthy with no signs of diarrhoea, and showed consistent weight gain. No pathological abnormalities were observed and the caecal contents were toxin-negative. These results suggest that temocillin therapy in humans is unlikely to cause significant disturbance of the gastrointestinal flora.