Metabolic engineering of L-cysteine supply modules for enhanced production of bacitracin in Bacillus licheniformis / 生物工程学报

Bacitracin is a broad-spectrum antibiotics mainly produced by Bacillus, and is used as veterinary medicine in the fields of livestock and poultry breeding. Insufficient supply of precursor amino acids might be an important factor that hinders high-level microbial production of bacitracin. We investigated the effect of strengthening L-cysteine supply on bacitracin production by an industrial bacitracin producer, Bacillus licheniformis DW2. Overexpression of cysK encoding L-cysteine synthase led to a 9.17% increase of the bacitracin titer. Moreover, overexpression of cysE encoding L-serine acetyltransferase and cysP encoding thiosulfate/sulfate intracellular transporter increased the bacitracin titers by 7.23% and 8.52%, respectively. Moreover, overexpression of a putative cystine importer TcyP led to a 29.19% increase of intracellular L-cysteine, and bacitracin titer was increased by 7.79%. Subsequently, the strong promoter PbacA was used to replace the promoters of genes cysP, cysE and tcyP in strain DW2::ysK, respectively. The resulted strain CYS4 (DW2::cysK-PbacA-(cysP)-PbacA(cysE)- PbacA(tcyP) produced 910.02 U/mL bacitracin, which was 21.10% higher than that of the original strain DW2 (747.71 U/mL). Together with the experiments in 3 L fermenters, this research demonstrated that enhancing intracellular L-cysteine supply is an effective strategy to increase bacitracin production of B. licheniformis.

Probiotic and synbiotic in broiler diet: performance and Enterobacteriaceae / [Probiótico e simbiótico em ração para frangos: desempenho e Enterobacteriaceae]

The objective of this study was to evaluate the effects of probiotics and synbiotics on the performance and Enterobacteriaceae count of broiler chickens. A total of 640 one-day-old male broiler chicks were distributed in a completely randomized design with four treatments and eight replicates with 20 birds each. The treatments were: ration with performance enhancer (zinc bacitracin; positive control); ration without performance enhancer and probiotic/synbiotic (negative control); ration with probiotics; and ration with synbiotics. At 35 days, five birds from each treatment were euthanized and intestinal contents were harvested for determining the Enterobacteriaceae count. The performance data and average colony-forming units (CFUs) transformed as log CFU/g were subjected to analysis of variance and Tukey's test. The effects of probiotics and synbiotics were observed in the initial phase, with supplemented birds exhibiting comparable weight gain to those supplemented with bacitracin. No effect of the treatment on broiler performance was observed after 42 days. The enterobacterial count was comparable among all experimental treatments. Supplementation with probiotics and synbiotics did not compromise the performance of broilers and did not alter the Enterobacteriaceae count.(AU)

Objetivou-se avaliar o efeito do probiótico e do simbiótico sobre o desempenho e a contagem de Enterobacteriaceae em frangos. Foram utilizados 640 pintos de corte, machos, de um dia de idade, distribuídos em delineamento inteiramente ao acaso, com quatro tratamentos, oito repetições com 20 aves cada. Os tratamentos foram: ração com melhorador de desempenho (bacitracina de zinco) (controle positivo); ração sem melhorador de desempenho e sem probiótico/simbiótico (controle negativo); ração com probiótico e ração com simbiótico. Aos 35 dias, cinco aves por tratamento foram eutanasiadas para retirada de conteúdo intestinal e determinação de Enterobacteriaceae. As médias das unidades formadoras de colônias, transformadas em log/UFC/g, e de desempenho foram submetidas à análise de variância e comparadas pelo teste Tukey. Foi observado efeito do probiótico e do simbiótico na fase inicial, sendo que aves apresentaram os mesmos resultados de ganho de peso e de peso corporal que o grupo de aves alimentado com bacitracina. Aos 42 dias, não houve efeito dos tratamentos sobre o desempenho. Aves que não receberam nenhum aditivo não apresentaram maior contagem de enterobactérias, sendo semelhantes aos demais tratamentos. A adição do probiótico e do simbiótico não compromete o desempenho dos frangos e não altera a contagem de Enterobacteriaceae.(AU)

Enhanced production of bacitracin via energy metabolism engineering in Bacillus licheniformis DW2 / 生物工程学报

Bacitracin is a broad-spectrum cyclic peptide antibiotic, and mainly produced by Bacillus. Energy metabolism plays as a critical role in high-level production of target metabolites. In this study, Bacillus licheniformis DW2, an industrial strain for bacitracin production, was served as the original strain. First, our results confirmed that elimination of cytochrome bd oxidase branch via deleting gene cydB benefited bacitracin synthesis. Bacitracin titer and ATP content were increased by 10.97% and 22.96%, compared with those of original strain, respectively. Then, strengthening cytochrome aa3 oxidase branch via overexpressing gene qoxA was conducive to bacitracin production. Bacitracin titer and ATP content were increased by 18.97% and 34.00%, respectively. In addition, strengthening ADP synthesis supply is also proven as an effective strategy to promote intracellular ATP accumulation, overexpression of adenosine kinase DcK and adenylate kinase AdK could all improve bacitracin titers, among which, dck overexpression strain showed the better performance, and bacitracin titer was increased by 16.78%. Based on the above individual methods, a method of combining the deletion of gene cydB and overexpression of genes qoxA, dck were used to enhance ATP content of cells to 39.54 nmol/L, increased by 49.32% compared to original strain, and bacitracin titer produced by the final strain DW2-CQD (DW2ΔcydB::qoxA::dck) was 954.25 U/mL, increased by 21.66%. The bacitracin titer produced per cell was 2.11 U/CFU, increased by 11.05%. Collectively, this study demonstrates that improving ATP content was an efficient strategy to improve bacitracin production, and a promising strain B. licheniformis DW2-CQD was attained for industrial production of bacitracin.

Staphylococcus aureus resistance to topical antimicrobials in atopic dermatitis

Abstract: Background: Topical antimicrobial drugs are indicated for limited superficial pyodermitis treatment, although they are largely used as self-prescribed medication for a variety of inflammatory dermatoses, including atopic dermatitis. Monitoring bacterial susceptibility to these drugs is difficult, given the paucity of laboratory standardization. Objective: To evaluate the prevalence of Staphylococcus aureus topical antimicrobial drug resistance in atopic dermatitis patients. Methods: We conducted a cross-sectional study of children and adults diagnosed with atopic dermatitis and S. aureus colonization. We used miscellaneous literature reported breakpoints to define S. aureus resistance to mupirocin, fusidic acid, gentamicin, neomycin and bacitracin. Results: A total of 91 patients were included and 100 S. aureus isolates were analyzed. All strains were methicillin-susceptible S. aureus. We found a low prevalence of mupirocin and fusidic acid resistance (1.1% and 5.9%, respectively), but high levels of neomycin and bacitracin resistance (42.6% and 100%, respectively). Fusidic acid resistance was associated with more severe atopic dermatitis, demonstrated by higher EASI scores (median 17.8 vs 5.7, p=.009). Our results also corroborate the literature on the absence of cross-resistance between the aminoglycosides neomycin and gentamicin. Conclusions: Our data, in a southern Brazilian sample of AD patients, revealed a low prevalence of mupirocin and fusidic acid resistance of S. aureus atopic eczema colonizer strains. However, for neomycin and bacitracin, which are commonly used topical antimicrobial drugs in Brazil, high levels of resistance were identified. Further restrictions on the use of these antimicrobials seem necessary to keep resistance as low as possible.

Bacitracin Inhibits the Migration of U87-MG Glioma Cells via Interferences of the Integrin Outside-in Signaling Pathway

OBJECTIVE: Protein disulfide isomerase (PDI) acts as a chaperone on the cell surface, and it has been reported that PDI is associated with the tumor cell migration and invasion. The aims of this study are to investigate the anti-migration effect of bacitracin, which is an inhibitor of PDI, and the associated factor in this process. METHODS: U87-MG glioma cells were treated with bacitracin in 1.25, 2.5, 3.75, and 5.0 mM concentrations. Western blot with caspase-3 was applied to evaluate the cytotoxicity of bacitracin. Adhesion, morphology, migration assays, and organotypic brain-slice culture were performed to evaluate the effect of bacitracin to the tumor cell. Western blot, PCR, and gelatin zymography were performed to investigate the associated factors. Thirty glioma tissues were collected following immunohistochemistry and Western blot. RESULTS: Bacitracin showed a cytotoxicity in 3rd (p<0.05) and 4th (p<0.001) days, in 5.0 Mm concentration. The cell adhesion significantly decreased and the cells became a round shape after treated with bacitracin. The migration ability, the expression of phosphorylated focal adhesion kinase (p-FAK) and matrix metalloproteinase-2 (MMP-2) decreased in a bacitracin dose- and time-dependent manner. The U87-MG cells exhibited low-invasiveness in the 2.5 mM, compared with the untreated in organotypic brain-slice culture. PDI was expressed in the tumor margin, and significantly increased with histological glioma grades (p<0.001). CONCLUSION: Bacitracin, as a functional inhibitor of PDI, decreased the phosphorylated FAK and the secreted MMP-2, which are the downstream of integrin and play a major role in cell migration and invasion, might become one of the feasible therapeutic strategies for glioblastoma.

Antimicrobial activity of different filling pastes for deciduous tooth treatment

Guedes-Pinto paste is the filling material most employed in Brazil for endodontic treatment of deciduous teeth; however, the Rifocort® ointment has been removed. Thus, the aim of this study was to investigate the antimicrobial potential of filling pastes, by proposing three new pharmacological associations to replace Rifocort® ointment with drugs of already established antimicrobial power: Nebacetin® ointment, 2% Chlorhexidine Gluconate gel, and Maxitrol® ointment. A paste composed of Iodoform, Rifocort® ointment and Camphorated Paramonochlorophenol (CPC) was employed as the gold standard (G1). The other associations were: Iodoform, Nebacetin® ointment and CPC (G2); Iodoform, 2% Chlorhexidine Digluconate gel and CPC (G3); Iodoform, Maxitrol® ointment and CPC (G4). The associations were tested for Staphylococcus aureus (S. aureus), Streptococcus mutans (S. mutans), Streptococcus oralis (S. oralis), Enterococcus faecalis (E. faecalis), Escherichia coli (E. coli), and Bacillus subtilis (B. subtilis), using the methods of dilution on solid medium – orifice agar – and broth dilution. The results were tested using statistical analysis ANOVA and Kruskal-Wallis. They showed that all the pastes had a bacteriostatic effect on all the microorganisms, without any statistically significant difference, compared with G1. S. aureus was statistically significant (multiple comparison test of Tukey), insofar as G2 and G3 presented the worst and the best performance, respectively. All associations were bactericidal for E. coli, S. aureus, S. mutans and S. oralis. Only G3 and G4 were bactericidal for E. faecalis, whereas no product was bactericidal for B. subtilis. Thus, the tested pastes have antimicrobial potential and have proved acceptable for endodontic treatment of primary teeth.

Antibiotic Susceptibility Evaluation of Group A Streptococcus Isolated from Children with Pharyngitis: A Study from Iran / 감염과화학요법

BACKGROUND: The aim of this study was to evaluate the antibiotic susceptibility of Group A streptococcus (GAS) to antibiotics usually used in Iran for treatment of GAS pharyngitis in children. MATERIALS AND METHODS: From 2011 to 2013, children 3-15 years of age with acute tonsillopharyngitis who attended Mofid Children's Hospital clinics and emergency ward and did not meet the exclusion criteria were enrolled in a prospective study in a sequential manner. The isolates strains from throat culture were identified as GAS by colony morphology, gram staining, beta hemolysis on blood agar, sensitivity to bacitracin, a positive pyrrolidonyl aminopeptidase (PYR) test result, and the presence of Lancefield A antigen determined by agglutination test. Antimicrobial susceptibility was identified by both disk diffusion and broth dilution methods. RESULTS: From 200 children enrolled in this study, 59 (30%) cases were culture positive for GAS. All isolates were sensitive to penicillin G. The prevalence of erythromycin, azithromycin, and clarithromycin resistance by broth dilution method was 33.9%, 57.6%, and 33.9%, respectively. Surprisingly, 8.4% of GAS strains were resistant to rifampin. In this study, 13.5% and 32.2% of the strains were resistant to clindamycin and ofloxacin, respectively. CONCLUSION: The high rate of resistance of GAS to some antibiotics in this study should warn physicians, especially in Iran, to use antibiotics restrictedly and logically to prevent the rising of resistance rates in future. It also seems that continuous local surveillance is necessary to achieve the best therapeutic option for GAS treatment.

Uso de óleo essencial de orégano, salinomicina e bacitracina de zinco na dieta de frangos de corte / Use of oregano essential oil, salinomycin and bacitracin zinc in diets of broiler chicken

O presente trabalho teve como objetivo avaliar dietas com óleo essencial de orégano, associado ou não com salinomicina, como alternativa à bacitracina de zinco sobre o desempenho zootécnico de frangos de corte. Foram utilizados 600 pintos de um dia de idade, machos, da linhagem Cobb® 500, criados até 42 dias de idade em boxes com cama de casca de arroz providos de comedouros tubulares e bebedouros nipple. O delineamento foi inteiramente casualizado, com seis dietas e 10 repetições de 10 aves cada. As dietas experimentais à base de milho e farelo de soja foram: controle positivo – antibiótico (bacitracina de zinco) + 0,05% de anticoccidiano (salinomicina), controle negativo – dieta basal (DB) sem aditivos, DB + 0,05% de salinomicina e 0,03% de óleo essencial de orégano (Orego-Stim®), DB + 0,03% de óleo essencial de orégano, DB + 0,05% de salinomicina e 0,05% de óleo essencial de orégano, DB + 0,05% de óleo essencial de orégano. Não foi encontrado efeito da utilização do óleo de orégano até 21 dias no desempenho das aves. Nos demais períodos, aos 35 e 42 dias, o desempenho das aves tratadas com 0,03% de óleo essencial de orégano + salinomicina apresentou resultados semelhantes ao controle positivo, levando à conclusão de que a dose de 0,03% de óleo essencial de orégano + salinomicina pode substituir a bacitracina de zinco + salinomicina em dietas para frangos de corte.

The inclusion of oregano essential oil, alone or associated with salinomycin, was evaluated as an alternative to zinc bacitracin on the performance of broiler chickens. This study used 600 male Cobb 500® day-old chicks, raised 42 days in boxes with rice hulls, provided with tubular feeders and nipple drinkers. The experimental design was completely randomized with six diets and 10 replications with 10 birds per experimental unit. The diets were based on corn and soybean meal: positive control - antibiotic (zinc bacitracin) + 0.05% anticoccidial (salinomycin), negative control - basal diet (BD) without additives, DB + 0.05% of salinomycin and 0.03% of oregano essential oil (Orego-Stim®), DB + 0.03% of oregano essential oil, DB + 0.05% of salinomycin and 0.05% of oregano essential oil, DB + 0.05% of oregano essential oil. There were no treatment effects on broiler performance until 21 days of age. In the other periods, at 35 and 42 days, the oregano essential oil at 0.03% combined with salinomycin presented similar effects as the positive control, leading to the conclusion that 0.03% of oregano essential oil associated with the salinomycin can replace zinc bacitracin + salinomycin in broiler chicken diets.

Inhibitory effect on Streptococcus mutans and mechanical properties of the chitosan containing composite resin

OBJECTIVES: This study evaluated the antibacterial effect and mechanical properties of composite resins (LCR, MCR, HCR) incorporating chitosan with three different molecular weights (L, Low; M, Medium; H, High). MATERIALS AND METHODS: Streptococcus (S). mutans 100 mL and each chitosan powder were inoculated in sterilized 10 mL Brain-Heart Infusion (BHI) solution, and was centrifuged for 12 hr. Absorbance of the supernatent was measured at OD660 to estimate the antibacterial activities of chitosan. After S. mutans was inoculated in the disc shaped chitosan-containing composite resins, the disc was cleansed with BHI and diluted with serial dilution method. S. mutans was spread on Mitis-salivarius bacitracin agar. After then, colony forming unit (CFU) was measured to verify the inhibitory effect on S. mutans biofilm. To ascertain the effect on the mechanical properties of composite resin, 3-point bending and Vickers hardness tests were done after 1 and 3 wk water storage, respectively. Using 2-way analysis of variance (ANOVA) and Scheffe test, statistical analysis was done with 95% significance level. RESULTS: All chitosan powder showed inhibition effect against S. mutans. CFU number in chitosan-containing composite resins was smaller than that of control resin without chitosan. The chitosan containing composite resins did not show any significant difference in flexural strength and Vickers hardness in comparison with the control resin. However, the composite resin, MCR showed a slightly decreased flexural strength and the maximum load than those of control and the other composite resins HCR and LCR. CONCLUSIONS: LCR and HCR would be recommended as a feasible antibacterial restorative due to its antibacterial nature and mechanical properties.

Production of peptide antibiotics by Bacillus sp: GU 057 indigenously isolated from saline soil

A total of 112 soil samples were taken from differents areas of district D.I.Khan and Kohat (KPK) Pakistan and screened for production of antibiotics against the Micrococcus luteus and Staphylococcus aureus. Widest zone of inhibition (18mm) was produced by microorganism isolated from saline soil. The strain was later identified as Bacillus GU057 by standard biochemical assays. Maximum activity (18mm inhibition zone) was observed against Staphylococcus aureus after 48 hours of incubation at pH 8 and 4% concentration of glucose. The antibiotic was identified by autobiography as bacitracin. The Bacillus strain GU057 was confirmed as good peptide antibiotic producer and can effectively be indulged as biocontrol agent.

Systematic mutagenesis method for enhanced production of bacitracin by Bacillus licheniformis mutant strain UV-MN-HN-6

The purpose of the current study was intended to obtain the enhanced production of bacitracin by Bacillus licheniformis through random mutagenesis and optimization of various parameters. Several isolates of Bacillus licheniformis were isolated from local habitat and isolate designated as GP-35 produced maximum bacitracin production (14±0.72 IU ml-1). Bacitracin production of Bacillus licheniformis GP-35 was increased to 23±0.69 IU ml-1 after treatment with ultraviolet (UV) radiations. Similarly, treatment of vegetative cells of GP-35 with chemicals like N-methyl N'-nitro N-nitroso guanidine (MNNG) and Nitrous acid (HNO2) increased the bacitracin production to a level of 31±1.35 IU ml-1 and 27±0.89 IU ml-1 respectively. Treatment of isolate GP-35 with combined effect of UV and chemical treatment yield significantly higher titers of bacitracin with maximum bacitracin production of 41.6±0.92 IU ml-1. Production of bacitracin was further enhanced (59.1±1.35 IU ml-1) by optimization of different parameters like phosphate sources, organic acids as well as temperature and pH. An increase of 4.22 fold in the production of bacitracin after mutagenesis and optimization of various parameters was achieved in comparison to wild type. Mutant strain was highly stable and produced consistent yield of bacitracin even after 15 generations. On the basis of kinetic variables, notably Yp/s (IU/g substrate), Yp/x (IU/g cells), Yx/s (g/g), Yp/s, mutant strain B. licheniformis UV-MN-HN-6 was found to be a hyperproducer of bacitracin.

Prevalência de Streptococcus pyogenes em crianças e adolescentes com 1 a 13 anos de idade, Teresina-PI, Brasil / Prevalence of Streptococcus pyogenes in children and adolescents with 1 to 13 years old, Teresina-PI, Brazil

O estudo teve o objetivo de identificar a prevalência de Streptococcus pyogenes na secreção de orofaringe em crianças e adolescentes com 1 a 13 anos de idade. Trata-se de uma abordagem quantitativa, na qual foi coletada secreção de orofaringe de 80 crianças e adolescentes moradores de uma vila na cidade de Teresina - PI. A cultura de orofaringe foi realizada em Trypticase Soy Agar acrescido de 5% de sangue de carneiro desfibrinado, seguido de incubação à temperatura de 35 +- 2o C em atmosfera de microaerofilia por 18-24 horas. A identificação do S pyogenes foi feita através da prova de catalase, sensibilidade a bacitracina e teste Pyrrolidonil Arilamidase (PYR)... A prevalência de S pyogenes encontrada está relacionada às condições geográficas sazonais, socioeconômicas e ambientais da região habitada. A importância do diagnóstico correto direciona a população para o tratamento adequado, visando a erradicação da bactéria, prevenindo as complicações supurativas e não supurativas, contribuindo também para o uso racional dos antimicrobianos.

The comparison of the characteristics of Streptococcus mutans isolated from caries free and high caries children / 대한구강보건학회지

OBJECTIVES: Streptococcus mutans (S. mutans) is the major causative bacteria in human dental decay. Most findings have shown that S. mutans are widely distributed in populations with moderate to high caries prevalence. However, observations have shown that S. mutans are also frequent in populations with low caries prevalence, as well. This study evaluated the relationship between the dental caries experience and the virulence factors of S. mutans, which are isolated from caries-free and high-caries individuals. METHODS: The dental caries experience states with the WHO diagnostic criteria, which were examined for children (aged 8 to 9 years) from two schools that are located in Daegu, Korea. A total of 22 caries-free (dfs+DFS=0) and 12 high-caries (dfs+DFS> or =14, ds+DS> or =9) were selected for this study. Dental plaque samples were obtained and incubated in MSB plate to culture S. mutans. After isolation and identification, the level of S. mutans, attachment ability, and streomicroscopy were analyzed. RESULTS: The S. mutans counts and attachment ability were higher in the high-caries group than in the caries-free group (P<0.05). In addition, the colonies isolated from the caries-free group adhered less strongly to the Mitis Salivarius Bacitracin agar. There were less of the sticky substances from the surface of the S. mutans colonies in the caries-free group. CONCLUSIONS: These results indicate that caries activity affected by the virulence not only the number of S. mutans.

Quantitative analysis of mutans streptococci adhesion to various orthodontic bracket materials in vivo / 대한치과교정학회지

OBJECTIVE: To estimate the effects of bracket material type on enamel decalcification during orthodontic treatment, this study analyzed the adhesion level of mutans streptococci (MS) to orthodontic bracket materials in vivo. METHODS: Three different types of orthodontic bracket materials were used: stainless steel, monocrystalline sapphire, and polycrystalline alumina. A balanced complete block design was used to exclude the effect of positional variation of bracket materials in the oral cavity. Three types of plastic individual trays were made and one subject placed the tray in the mouth for 12 hours. Then, the attached bacteria were isolated and incubated on a mitis salivarius media containing bacitracin for 48 hours. Finally, the number of colony forming units of MS was counted. The experiments were independently performed 5 times with each of the 3 trays, resulting in a total of 15 times. Mixed model ANOVA was used to compare the adhesion amount of MS. RESULTS: There was no difference in colony forming units among the bracket materials irrespective of jaw and tooth position. CONCLUSIONS: This study suggested that the result of quantitative analysis of MS adhesion to various orthodontic bracket materials in vivo may differ from that of the condition in vitro.

Microbiological Characteristics of Throat Cultures from School Children in Jinju, 2006 / 대한임상미생물학회지

BACKGROUND: Group A streptococci (GAS) are the most common cause of pharyngitis in children. The streptococci in throat cultures from healthy elementary school children in Jinju were compared with previous results. METHODS: Throat cultures were taken from 1,402 healthy school children in 2006. beta-hemolytic streptococci (BHS) were identified with a bacitracin disk (0.04 U) and latex agglutination test (Seroiden Strepto Kit, Eiken, Tokyo, Japan). RESULTS: Two-hundred sixteen (15.4%) and 149 (10.6%) cultures grew BHS and GAS, respectively. The isolation rate of GAS was significantly lower than in 2004 (16.0%) or 2002 (16.9%) (P<0.05). Among BHS, the prevalence of group A strains (69.0%) decreased significantly compared with 2004 (84.9%) and 2002 (83.8%) (P<0.05). None of the 1st-grade children yielded BHS or GAS. CONCLUSION: The isolation rates of BHS and GAS from healthy school children were lower in 2006 than in previous years. Natural immunization against the common serotypes or improvement in individual hygiene might have played roles in the reduction of isolations of GAS.

Antibiotic resistance profile: isolation and characterization of clinical isolates of staphylococci from patients with community-acquired skin infections

Although most bacterial infections of the skin bear out to be minor in nature, a few such dermatologic entities are major, to the spot of yet being fatal. The mortality rate is usually up to 30% to 50% and depends upon the type of infection, original disease, and resistant type. In this study hundred and five bacterial strains were isolated from skin wounds, burns and acne patients from hospitals at different locations in the cosmopolitan city of Karachi. These bacterial strains were identified by conventional methods. Seventy two percent [72%] of total isolated organisms were found to be Staphylococcus aureus while the remaining thirty three percent [33%] were Staphylococcus epidermidis. The antibiotic resistance of identified organisms was carried out by disc-diffusion method with commercially available disc of five antibiotics having different mode of actions such as cell wall synthesis inhibitors, membrane permeability alternatives and DNA synthesis inhibitors. Staphylococcus aureus show more resistant to these antibiotics as compared to Staphylococcus epidermidis. The most effective antibiotic for Staphylococcus aureus is vancomycin showing 80.5% efficacy, then methicillin with 68.0% efficacy, erythromycin with 55.6% efficacy, novobiocin with 54.1% efficacy and then bacitracin with 25.0% efficacy. The most effective antibiotic for Staphylococcus epidermidis is methicillin showing 84.8% efficacy, then vancomycin with 81.2% efficacy, novobiocin with 63.6% efficacy, erythromycin with 42.4% efficacy and then bacitracin with 27.8% efficacy

[Statistical study of laboratory diagnostic tests of streptococcus pyogens]

Bacteria of species Streptococcus pyogenes are a human pathogen, causing serious invasive infections. The culture method remains the standard way for its isolation and identification. Due to the accessible facilities, medical laboratories employ different methods in this way. In present study the most common methods have been statistically interpreted. A total of 159 beta-hemolytic streptococci isolated from different samples were tested for hemolysis potency, sensitivity to bacitracin [BC] or sulfametoxazole/trimethoprim [SXT] and Voges-proskauer [V.P]. Based on L-pyrrolidonyl-beta-naphthylamide [PYR] test, the positive predicted value [ppv], negative predicted value [npv] and sensitivity [sen] of each test were calculated. The ppv, npv and sen. of beta-hemolysis on sheep blood agar [SBA] for identification of S. pyogenes were 75, 89 and 89% respectively. It was 76, 89 and 53% for banked human blood [BHB]. For BC test the above mentioned criteria were 52, 70 and 89% and also for VP test 57, 89, and 94%. Finally SXT test with 49, 47 and 63% demonstrated the least practical identification value. The PYR test is considered the most reliable biochemical test for identification of S. pyogenes among other beta hemolytic streptococci. If it is not available, combining of hemolysis >/= 3mm with BC >/= 10mm has presumptive identification value of 89%. It was realized that the hemolytic activity of this bacterial species on BHB is documented and equal to a potent hemolysis on SBA. The VP test with 89% value is a suitable test to rule out its presence; but the accuracy of SXT test result is limited

Degradation of recombinant hirudin-2 in nasal mucosa of rabbits in vitro / 药学学报

<p><b>AIM</b>To investigate the degradation of recombinant hirudin-2 (rHV2) in nasal mucosa of rabbit.</p><p><b>METHODS</b>The specific and accurate HPLC method was developed for analyzing rHV2; The degrading ratios of rHV2 at different concentrations and at pH conditions in rabbit nasal mucosa homogenate were determined; The results in nasal mucosa homogenate were compared with that in small intestinal mucosa homogenate of rabbits. The stability of rHV2 in the enzyme extract of nasal mucosa surface and the effect of proteolysis inhibitor bacitracin on the degradation of rHV2 in nasal mucosa homogenate were also estimated.</p><p><b>RESULTS</b>The degradation of rHV2 in rabbit nasal mucosa homogenate showed concentration- and pH-dependence; rHV2 in nasal mucosa homogenate was more stable than that in intestinal mucosa homogenate. Also rHV2 was more stable in the enzyme extracts of nasal serosal surface than that of mucosa surface. Addition of bacitracin was able to inhibit the degradation to some degree.</p><p><b>CONCLUSION</b>Comparing with oral administration, rHV2 nasal delivery was a more tolerant route.</p>

Comparison of preoperative anti-infective preparations for extracapsular lens extraction

Objective: To investigate the effect of three preoperative anti-infective regimens on the sterility of anterior-chamber aspirates (ACA) in eyes undergoing extracapsular cataract extraction (ECCE). Methods: Ninety eyes scheduled to undergo ECCE were randomly assigned to receive one of the following preoperative anti-infective regimens: Group 1 (Control) - no additional preoperative preparation; Group 2 (Eye drop) - neomycin/ polymixin B/gramicidin eye drops applied 3 times daily for 3 days prior to surgery; and Group 3 (Lid scrub) - neomycin/polymixin B/ bacitracin ointment lid scrub applied 3 times prior to surgery. ACAs were obtained from all eyes at the conclusion of surgery and cultured. The patients were followed up for 3 months after the surgery. Results: Positive cultures developed from ACAs in 5 (16.6 percent) of 30 eyes from Group 1, in 0 of 30 from Group 2, and in 3 (10 percent) of 30 from Group 3. No eye developed endophthalmitis. Compared with the control group, preoperative neomycin/polymixin B/gramicidin eye drops significantly reduced the ACA contamination rate (p= 0.03). Conclusion: Preoperative neomycin/polymixin B/bacitracin eyedrops can improve the sterility of the anterior chamber during ECCE.