Virginiamycin and sodium monensin supplementation for beef cattle on pasture / Suplementação com virginiamicina e monensina sódica para bovinos de corte a pasto

The aim of this paper was to evaluate the effects of including virginiamycin (VM), sodium monensin (MON) or the association (VM+MON) in the energetic mineral supplement, on the intake and performance of beef cattle on pasture. Forty Nellore heifers with 24 months of age and initial body weight (BW) of 251.5±16.6kg, were distributed in four treatments in a randomized block design. Treatments consisted of adding VM, MON or VM+MON to the supplement (CONT). Additive concentrations were defined to reach a dose of 40 to 45mg/100kg BW. The herbage allowance was not a limiting factor for the animals' intake. Supplement intake was lower than expected, with 33.0, 18.8 and 26.3mg per 100kg BW for VM, MON and VM+MON, respectively. Dry matter intake (DMI, mean=2.65% BW) and animal performance were not affected by the inclusion of additives. The average daily gain (ADG) was 0.561kg/animal day-1. The inclusion of additives in energetic mineral supplement does not affect the DMI and the ADG of grazing animals. The variability in supplement intake and daily dose intake of additives may have influenced the performance of the animals. Monensin inclusion presented the less expensive supplementation cost, due to reduction in supplement intake without changing weight gain.(AU)

Objetivou-se avaliar o efeito da inclusão dos aditivos virginiamicina (VM), monensina sódica (MON) e associação (VM+MON) no suplemento energético-mineral sobre o consumo e desempenho de bovinos manejados em pastagem de Urochloa Brizantha cv. Marandu. Foram utilizadas 40 novilhas Nelore com 24 meses de idade e peso corporal (PC) inicial médio de 251,5+16,6kg distribuídas em delineamento em blocos ao acaso com quatro tratamentos. Os tratamentos consistiam de suplemento energético-mineral (CONT) acrescido de VM, MON ou VM+MON. A oferta de forragem não limitou o consumo dos animais. O consumo dos aditivos foi de 0; 33,0; 18,8 e 26,3mg por 100kg de PC para CONT, VM, MON e VM+MON, respectivamente. O consumo de matéria seca e o desempenho dos animais não foram afetados pela inclusão dos aditivos. O ganho médio diário dos animais foi de 0,561kg dia -1 , sem diferença entre os tratamentos. A inclusão de aditivos no suplemento energético-mineral não alterou o CMS e o desempenho dos animais em pastejo. A variabilidade no consumo de suplemento e na dose ingerida dos aditivos pode ter influenciado o desempenho dos animais.(AU)

Efficacy of virginiamycin for the control of periodontal disease in calves / Eficácia da virginiamicina no controle de doença periodontal em bezerros

Periodontal diseases are multifactorial infectious processes caused by complexes of microorganisms, with damage to health, production, and animal welfare. The aim of the present study was to evaluate the efficacy of virginiamycin in the prevention and control of two early forms of periodontal disease: gingivitis and necrotizing gingivitis. Ten weaned calves, aged four to six months, were permanently kept in a single lot under the same rotational grazing regime in a newly reformed area of Panicum maximum. Five of the calves were orally administered 340mg of virginiamycin (Virginiamycin Group) daily for a period of 18 weeks, while the remaining five calves (Control Group) remained under the same food management but did not receive virginiamycin. During this period, animals underwent 18 weekly evaluations regarding periodontal health, with monitoring and recording of clinical parameters of the eight deciduous incisor teeth on the labial and lingual faces. At approximately two-week intervals, nine collections of subgingival sulcus material from five sites of the four right incisor teeth of each animal were performed and subjected to microbiological evaluation using polymerase chain reaction with primers of 25 microorganisms considered potentially pathogenic. After 1440 periodontal clinical evaluations of incisor teeth of the 10 calves, a total of 395 episodes of gingivitis were recorded, of which 267 occurred in the Control Group and 128 in the Virginiamycin Group. Similarly, 89 episodes of necrotizing gingivitis were recorded; 58 in the Control Group and 31 in the Virginiamycin Group. Comparison of between-group means found significant differences for teeth with gingivitis and necrotizing gingivitis (t test; p<0.05). The total number of teeth with gingivitis (p<0.01) and necrotizing gingivitis (p<0.01) in Control Group was significantly higher than that of gingivitis (p<0.01) and necrotizing gingivitis (p<0.05) in the Virginiamycin Group. There was a positive correlation between total occurrence of gingivitis and necrotizing gingivitis in the Virginiamycin Group by Pearson's test. Virginiamycin had a protective effect on treated animals compared with the Control Group (OR = 0.36: CI (95%) = 0.27-0.43). In the Control Group, Actinomyces israelli (4.74%), domain Archaea (1.58%), Eikenella corrodens (1.05%), Fusobacterium nucleatum (27.37%), class Mollicutes (5.26%); Porphyromonas endodontalis(5.26%); Porphyromonas gulae(0.53%), Prevotella buccae (6.32%), Prevotella loescheii (3.68%), Prevotella nigrescens (8.42%), Prevotella oralis (1.58%), Tannerella forsythia (0.53%), and Treponema denticola (4.21%) were detected at healthy sites, and gingivitis or necrotizing gingivitis samples. In the Virginiamycin Group, A. israelli (3.41%), domain Archaea (0.98%), F. nucleatum (9.27%), class Mollicutes(4.39%), P. endodontalis (4.39%), P. gulae (0.49%), P. buccae (8.29%), P. loescheii (6.83%), P. nigrescens (15.61%), P. oralis (1.46%), Selenomonas sputigena (0.49%), T. forsythia (0.49%), and T. denticola (2.44%) were detected. In conclusion, virginiamycin administered at a dosage of 340mg/animal/day significantly reduced the occurrence of gingivitis and necrotizing gingivitis in cattle maintained on reformed pastures, and was revealed to have action against periodontal bacterial microbiota considered to be potentially pathogenic.(AU)

As doenças periodontais são processos infecciosos multifatoriais causados por complexos de micro-organismos, que provocam danos à saúde, produção e ao bem-estar animal. O objetivo do presente estudo foi o de avaliar a eficácia da virginiamicina na prevenção e controle de duas formas de doença periodontal; a gengivite e a gengivite necrosante. Assim, dez bezerros desmamados, com idade entre 4 e 6 meses, foram mantidos permanentemente em lote único e sob o mesmo regime de pastejo rotacionado em área reformada de Panicum maximum. Cinco bezerros receberam via oral 340mg de virginiamicina (Grupo Virginiamicina) diariamente, por um período de dezoito semanas, enquanto o Grupo Controle permaneceu sob o mesmo manejo alimentar, mas sem receber a virginiamicina. No período, os animais passaram por 18 avaliações semanais quanto à saúde periodontal, com monitoramento e registro dos parâmetros clínicos dos oito dentes incisivos decíduos, nas suas faces labial e lingual. Em intervalos aproximadamente quinzenais foram realizadas nove coletas de material do sulco subgengival de cinco sítios de quatro dentes incisivos direitos de cada animal para avaliação microbiológica, com o emprego da reação em cadeia da polimerase e com iniciadores de 25 micro-organismos considerados potencialmente patogênicos. Ao final das 1440 avaliações clínicas periodontais dos dentes incisivos dos dez bezerros, pôde-se registrar um total de 395 episódios de dentes com gengivite, nos quais 267 foram registrados no Grupo Controle e 128 no Grupo Virginiamicina. De forma semelhante, do total de 89 registros de gengivite necrosante, 58 foram no Grupo Controle e 31 no Grupo Virginiamicina. Na comparação entre médias dos grupos as diferenças encontradas para dentes com gengivite e gengivite necrosante foram significativas pelo teste t (p<0,05). Assim, o total de dentes com gengivite (p<0,01) e gengivite necrosante (p<0,01) no Grupo Controle, foi significativamente superior ao de gengivite (p<0,01) e gengivite necrosante (p<0,05) do Grupo Virginiamicina. Houve correlação positiva entre o total de ocorrência de gengivite e gengivite necrosante no Grupo Virginiamicina pelo teste de Pearson. A virginiamicina possuiu um efeito protetor nos animais tratados em comparação com o controle (OR = 0,36: IC (95%) = 0,27-0,43). Na avaliação microbiológica do Grupo Controle foram detectados nas amostras de sítios sadios, com gengivite ou com gengivite necrosante Actinomyces israelli (4,74%), domínio Archaea (1,58%), Eikenella corrodens (1,05%), Fusobacterium nucleatum (27,37%), classe Mollicutes (5,26%), Porphyromonas endodontalis (5,26%), Porphyromonas gulae (0,53%), Prevotella buccae (6,32%), Prevotella loescheii (3,68%), Prevotella nigrescens (8,42%), Prevotella oralis (1,58%), Tannerella forsythia (0,53%) e Treponema denticola (4,21%). Enquanto no Grupo Virginiamicina foram detectados: A. israelli (3,41%), domínio Archaea (0,98%), F. nucleatum (9,27%), classe Mollicutes (4,39%), P. endodontalis (4,39%), P. gulae (0,49%), P. buccae (8,29%), P. loescheii (6,83%), P. nigrescens (15,61%), P. oralis (1,46%), Selenomonas sputigena (0,49%), T. forsythia (0,49%) e T. denticola (2,44%). Em conclusão, a virginiamicina administrada na dosagem de 340mg/animal/dia reduziu significativamente a ocorrência da gengivite e gengivite necrosante em bovinos mantidos em pastos reformados e revelou ter ação frente à microbiota bacteriana periodontal considerada potencialmente patogênica.(AU)

Antimicrobial susceptibility of Streptococcus sp. to quinupristin-dalfopristin in China / 生物医学与环境科学（英文）

This study aimed to determine the in vitro activity of quinupristin-alfopristin against Streptococcus sp. isolated in China. This agent is not yet available for clinical use, but it has been tested against a high proportion of resistant Staphylococcus aureus strains. A total of 156 streptococcal isolates, which were recovered from various geographic areas and diseases, were tested using the Etest (AB Biodisk, Solna, Sweden). Quinupristin-alfopristin showed excellent activity against all of the tested streptococci isolates. These results provide useful data for the clinical use of quinupristin-alfopristin in China.

effects of comparison of herbal extracts, antibiotic, probiotic and organic acid on serum lipids, immune response, GIT microbial population, intestinal morphology and performance of broilers

With the removal of antibiotic as growth promoters from poultry diets, it is of interest to investigate potential alternatives to maintain good growth performance and good intestinal microbial populations in these birds. Numerous additives such as Probiotics, prebiotics, organic acids, enzymes and herbal extracts used extensively in poultry feed. The study was conducted to investigate the effects of herbal extracts, probiotic, organic acid and antibiotic on serum lipids, immune response, intestinal morphology, microbial population and performance of broilers. A total of 300 day - old male broilers [Cobb 500] were randomly divided into four treatments, five replicates with 15 birds in each. Treatments included: control, herbal extracts [Sangrovit [R]], probiotic [Primalac[R]], organic acid [Termin-8[R]] and antibiotic [Virginiamycin]. The highest weight gain [WG] were achieved by virginiamycin [p<0.05]. Moreover, highest and lowest antibody titers against SRBC were observed in Primalac_ and virginiamycin treatments, respectively [p<0.05]. Lowest serum cholesterol and triglyceride were obtained by Primalac[R] and Sangrovit_ [p<0.05]. The lowest and highest coliform bacteria counts in ileum were seen in virginiamycin and control groups, respectively [p<0.05]. It has been concluded that Sangrovit[R], Primalac[R] and Termin-8[R] reduced pathogenic bacteria in digestive tract of broilers, which can help to improve intestinal health of these animals. Thus, these can be used as antibiotic alternatives in broilers feed

Antimicrobial Resistance of Enterococcal Isolates from Blood and Risk Factors for Vancomycin Resistant Enterococcal Bacteremia in a Tertiary Care University Hospital from 2003 to 2007 / 대한임상미생물학회지

BACKGROUND: In Korea, a sudden increase in vancomycin-resistant enterococci (VRE) infection has been noted since the late 1990s. This study was conducted to describe the antimicrobial resistances of enterococcal blood isolates and to identify risk factors associated with VRE bacteremia in a tertiary care university hospital over a recent five-year period. METHODS: This study was conducted to analyze the antimicrobial susceptibilities of enterococcal blood isolates by year from January 2003 to December 2007. Multivariate logistic regression analysis was used to investigate factors associated with VRE bacteremia. RESULTS: A total of 225 enterococcal strains (44.7% Enterococcus faecalis, 42.4% Enterococcus facium, 5.9% Enterococcus casseliflavus, and 4.7% Enterococcus gallinarum) were detected in blood, 55 of which (21.6%) were resistant to vancomycin. In 2004 and 2005, the resistance rates for vancomycin and teicoplanin (33.3% and 27.3%; 34.4% and 23.0%, respectively) increased. In 2003, 2006, and 2007, the resistance rates for vancomycin and teicoplanin (8.7% and 8.7%; 19.0% and 14.3%; 13.5% and 11.5%, respectively) decreased relative to those of the previous years. When 55 patients with VRE bacteremia were compared with 55 patients with vancomycin-susceptible enterococcal bacteremia using multivariate analysis, E. faecium bacteremia (OR 12.624, P<0.001) and enterococcal bacteremia caused by species other than E. faecium and E. faecalis (OR 21.473, P=0.011) were found to be statistical risk factors. Among several infection control activities, the restricted uses of vancomycin and quinupristin-dalfopristin decreased the vancomycin resistance rate from 27.78% to 15.50% (P=0.0257). CONCLUSION: VRE bacteremia would be effectively controlled via infection control activities based on studies regarding risk factors associated with VRE bacteremia.

[ comparison between the effect of thyme, coneflower, garlic extracts and virginiamycin antibiotic on lipids serum, hematocrit percentage and hemoglobin concentration in broilers]

Poultry Meat is one of the major sources of human food. The cholesterol level in poultry productions could be monitored by feeding different medicinal plants. The medicinal plants have hypolipidemic and antioxidant properties. The aim of this study was comparison hypolipidemic effect, hematocrit percentage and hemoglobin concentration in broilers given three commercial herbal extracts and virginiamycin. A total four hundred and eighty 1-d-old male broiler chicks were assigned to the basal diet [control] and 0.15% [V/V] virginiamycin, 0.1 [V/V] extracts of thyme [Thymus vulgaris], coneflower [Echinacea purpurea], garlic [Allium sativum] and blend of extracts with the same dose were added to water. Total cholesterol [TC], LDL cholesterol, triglycerides [TG], HDL cholesterol, hematocrit percentage and hemoglobin concentration were measured after 42 days. Garlic [Allium sativum]significantly reduced the levels of TC, LDL and TG and significantly increased the level of HDL. Thyme [Thymus vulgaris] improved hematocrit percentage and hemoglobin concentration, but not significantly. Herbal extracts could improve blood factors in comparison with the control and antibiotic fed birds

Antibiotic therapeutic options for infections caused by drug-resistant Gram-positive cocci

Serious infections caused by Gram-positive bacteria are currently difficult to treat because many of these pathogens are now resistant to standard antimicrobial agents. As a result of the emergence and spread of multidrug-resistant Gram-positive pathogens, new antimicrobial agents are urgently needed for clinical use. In recent years, there has been an increase in the number of drugs that have activity against these Gram-positive pathogens. Daptomycin, tigecycline, linezolid, quinupristin/dalfopristin and dalbavancin are five antimicrobial agents that are useful for the treatment of infections due to drug-resistant Gram-positive cocci. This review focuses on their mechanism of action, pharmacokinetics, spectrum of activity, clinical effectiveness, drug interaction and safety. These antimicrobial agents provide the clinician with additional treatment options among the limited therapies for resistant Gram-positive bacterial infection

Clinical Manifestation and Treatment of Methicillin-resistant Staphylococcus aureus Infections in Children / 소아감염

Methicillin-resistant Staphylococcus aureus (MRSA), a leading cause of nosocomial infections, has been increasingly recognized in communities of the United States. This article will review the clinical spectrum and treatment of MRSA infections in children in the context of recent epidemiological changes of MRSA infections. In general, community-associated (CA) MRSA most frequently causes skin and soft tissue infections and has an increased association with invasive infections, particularly pneumonia and musculoskeletal infections. Hospital-associated (HA) MRSA strains tend to be associated with bloodstream infections, pneumonia, and surgical site infections. Different from the United States, CA-MRSA infections are not common in Korea (only 5.9%); however, there are some CA-MRSA clones that are different from HA- MRSA clones in Korea and from CA-MRSA clones in other countries. The treatment of MRSA infections should be guided by antimicrobial susceptibility testing, the site of infection, and the infection severity. Vancomycin is the treatment of choice for invasive MRSA infections. Other agents such as trimethoprim- sulfamethoxazole, clindamycin, linezolid, quinupristin-dalfopristin, and daptomycin have been used for some conditions.

New Antimicrobial Agents for Children / 소아감염

There are relatively few novel antimicrobial agents despite the dramatic increase in antimicrobial resistance and multiple drug resistance of clinical isolates worldwide. Vancomycin is still the most widely used antibiotic for treating resistant Gram-positive coccal infections in children, especially for methicillin-resistant Staphylococcus aureus. For children with Gram-positive coccal infections where vancomycin is not effective or older therapeutic agents cannot be tolerated, linezolid, quinupristin-dalfopristin or daptomycin may be useful in the appropriate clinical setting. For Gram-negative infections, new carbapenems await clinical application. Tebipenem pivoxil is a novel oral carbapenem undergoing clinical trials for acute otitis media in pediatric patients. Antiviral drug development is now progressing at the pace of antibiotic development 30 years ago. Newer antiviral agents used for the treatment of herpes viruses and hepatitis C virus infections in children are included in this review.

Comparison of the MicroScan(R) Combo Panel Synergies plus with the MicroScan(R) Conventional Combo Panel for Diagnostic Performance of Gram-negative and Gram-positive Bacteria / 대한임상미생물학회지

BACKGROUND: To access the clinical usefulness of MicroScan(R) Synergies plus Combo Panels (Siemens, USA) for the identification and antimicrobial susceptibility test (AST) of Gram-negative bacteria (GNB) and Gram-positive cocci (GPC), we compared MicroScan(R) Synergies plus Combo Panels with MicroScan(R) conventional Combo Panels. METHODS: One-hundred four isolates of GNB were simultaneously tested with MicroScan(R) Synergies plus Neg Combo Type 2 Panel (SINC2) and MicroScan(R) Neg Combo Panel Type 44 (NC44). One-hundred isolates of GPC were simultaneously tested with MicroScan(R) Synergies plus Pos Combo 3 Panel (SIPC3) and MicroScan(R) Pos Combo 1A (PC1A). RESULTS: Of the GNB isolates, agreement rate of identification between SINC2 and NC44 were 92.3% to the species level and 93.3% to the genus level. Of the GPC isolates, agreement rate of identification between SIPC3 and PC1A were 85.0% to the species level and 100% to the genus level. Of the GNB isolates, agreement rate of AST according to antimicrobial agents between SINC2 and NC44 ranged from 86.5% to 100%. Among GPC isolates, agreement rate of AST according to antimicrobial agents between SIPC3 and PC1A were higher than 96.0% with the exception of gentamicin and quinupristin-dalfopristin. CONCLUSION: Compared with MicroScan(R) conventional Combo Panels (NC44, PC1A), MicroScan(R) Synergies plus Combo Panels (SINC2, SIPC3) showed high agreement rate of identification and AST, and had the advantage of more rapid reporting.

In Vitro Antibiotic Susceptibility of Orientia tsutsugamushi strain Boryong Measured by Flow Cytometry / 감염과화학요법

BACKGROUND: Scrub typhus, an infectious disease caused by Orientia tsutsugamushi, is endemic in Korea. With the introduction of tetracycline and chloramphenicol in clinical practice, the mortality due to scrub typhus has markedly decreased. In 1995, scrub typhus poorly responsive to doxycycline was reported in Thailand; the need for safe antibiotics for the treatment of scrub typhus acquired during pregnancy or for children is emerging; also, broader spectrum antibiotics having anti-Orientia activity may be preferred for empirical therapy of enteric fever syndrome and for complicated scrub typhus. The anti-Orientia activities of various antibiotics, including recently licensed antibiotics, were investigated by flow cytometry. MATERIALS AND METHODS: O. tsutsugamushi strain Boryong was inoculated into the ECV304 cell line. The infected cells were stained with FS15, a monoclonal antibody reacting against a linear epitope on 56-kDa major outer membrane protein of O. tsutsugamushi. Then the antimicrobial susceptibilities were measured by flow cytometry and expressed as a growth index (total mass of Orientia). A concentration at which no further decrease in growth index occurred was defined as the minimal inhibitory concentration (MIC). Microbial susceptibilities to the following antibiotics were measured: quinupristin-dalfopristin (Synercid), levofloxacin, ciprofloxacin, moxifloxacin, metronidazole, linezolid, clindamycin, chloramphenicol, doxycycline, azithromycin, and rifampin. RESULTS: Considering the usual serum concentrations of rifampin (MIC=0.025-0.05 microg/mL), azithromycin (MIC=0.05-0.5 microg/mL) and doxycycline (MIC=0.05-0.1 microg/mL), these antibiotics exhibited very low MICs. Synercid (MIC=0.2-1.0 microg/mL), clindamycin (MIC=1.0 microg/mL) and chloramphenicol (MIC=1-2 microg/mL) exhibited moderately low MICs; moxifloxacin (MIC=8 microg/mL), ciprofloxacin (MIC=25.6 microg/mL or more) and levofloxacin (MIC=30 microg/mL) exhibited relatively high MICs; and cefotaxime (MIC>50 microg/mL), metronidazole (MIC>30 microg/mL) and linezolid (>30 microg/mL) exhibited high MICs. CONCLUSIONS: Among the new antibiotics, none was superior to doxycycline, azithromycin or rifampin with respect to anti-Orientia activity. Synercid, clindamycin, and moxifloxacin may show moderate therapeutic efficacies in human.

Comparison of the effects of propolis and virginia mycine on performance and immune response of broiler chicks

Three hundred and sixty male day- old Ross 308 broiler chicks were randomly assigned to four dietary treatments in order to evaluate the effect of propolis as growth promoter on the performance and the immune response of the broiler chicks to the ND vaccine. Each treatment contained three replicates of 30 chicks. Dietary treatments were as follow: Acorn - soy meal diet [control diet].Control diet + 3000 ppm [starter] and 2000 ppm [grower and finisher] propolis.Control diet + 6000 ppm [starter] and 4000 ppm [grower and finisher] propolis. Control diet + 100 ppm virginiamycine.The chick performance was evaluated by recording the body weight gain, feed intake, feed conservation ratio, and productive efficiency index at 21 and 42 days of age. Prior to the administration of ND vaccine [day 17] and 10 days post-vaccination, the blood sample was taken for HI test. The chicks fed diet supplemented with virginiamycin showed higher BWG, FI, PEI when compared with other treatments. However, those chick provided with dietary treatment 2 [3000 and 2000 ppm] had lower FCR. Propolis had no effect on antibody titer against ND vaccine. In this experiment propolis don't act as an immunostimulant, but appeared to be promising a potential growth promoter

In Vitro Antibiotic Susceptibility of Orientia tsutsugamushi strain Boryong Measured by Flow Cytometry / 감염과화학요법

BACKGROUND: Scrub typhus, an infectious disease caused by Orientia tsutsugamushi, is endemic in Korea. With the introduction of tetracycline and chloramphenicol in clinical practice, the mortality due to scrub typhus has markedly decreased. In 1995, scrub typhus poorly responsive to doxycycline was reported in Thailand; the need for safe antibiotics for the treatment of scrub typhus acquired during pregnancy or for children is emerging; also, broader spectrum antibiotics having anti-Orientia activity may be preferred for empirical therapy of enteric fever syndrome and for complicated scrub typhus. The anti-Orientia activities of various antibiotics, including recently licensed antibiotics, were investigated by flow cytometry. MATERIALS AND METHODS: O. tsutsugamushi strain Boryong was inoculated into the ECV304 cell line. The infected cells were stained with FS15, a monoclonal antibody reacting against a linear epitope on 56-kDa major outer membrane protein of O. tsutsugamushi. Then the antimicrobial susceptibilities were measured by flow cytometry and expressed as a growth index (total mass of Orientia). A concentration at which no further decrease in growth index occurred was defined as the minimal inhibitory concentration (MIC). Microbial susceptibilities to the following antibiotics were measured: quinupristin-dalfopristin (Synercid), levofloxacin, ciprofloxacin, moxifloxacin, metronidazole, linezolid, clindamycin, chloramphenicol, doxycycline, azithromycin, and rifampin. RESULTS: Considering the usual serum concentrations of rifampin (MIC=0.025-0.05 microg/mL), azithromycin (MIC=0.05-0.5 microg/mL) and doxycycline (MIC=0.05-0.1 microg/mL), these antibiotics exhibited very low MICs. Synercid (MIC=0.2-1.0 microg/mL), clindamycin (MIC=1.0 microg/mL) and chloramphenicol (MIC=1-2 microg/mL) exhibited moderately low MICs; moxifloxacin (MIC=8 microg/mL), ciprofloxacin (MIC=25.6 microg/mL or more) and levofloxacin (MIC=30 microg/mL) exhibited relatively high MICs; and cefotaxime (MIC>50 microg/mL), metronidazole (MIC>30 microg/mL) and linezolid (>30 microg/mL) exhibited high MICs. CONCLUSIONS: Among the new antibiotics, none was superior to doxycycline, azithromycin or rifampin with respect to anti-Orientia activity. Synercid, clindamycin, and moxifloxacin may show moderate therapeutic efficacies in human.

Antimicrobial Resistance and Multilocus Sequence Typing of Vancomycin-Resistant Enterococcus faecium Isolated from Clinical Specimens

A total of 58 vancomycin-resistant E. faecium (VREF) was isolated from 3 hospitals located in Daegu, Korea. The VREF isolates were evaluated for the antimicrobial susceptibility pattern and resistance determinants against vancomcin, aminoglycosides, and macrolides. The multilocus sequence types (MLST) were determined to characterize the clonal diversity of the VREF isolates. The VREF isolates were highly resistance to teicoplanin, erythromycin, ciprofloxacin, gentamicin, and streptomycin, whereas quinupristin-dalfopristin and linezolid were the most susceptible drugs. All isolates carried the vanA gene. The aac6'-aph2" (n=53) and aadE (n=27) genes were detected in the high-level aminoglycoside resistant (HLAR) isolates. The aac6'-aph2" gene was located in the conjugally transferable plasmids. The ermB and ermA genes were detected in the 54 and 3 VREF isolates, respectively. The VREF isolates showed 11 different sequence types (ST). The VREF isolates belonging to ST192 was the most prevalent (n=19), but detected in one hospital, whereas the isolates belonging to ST203 (n=11) were detected in 3 hospitals. These results suggest that the VREF isolates resistant to aminoglycosides and erythromycin are originated from different clones and specific VREF clones are spread in the study hospitals.

In vitro activity of antimicrobial agents against oxacillin resistant staphylococci with special reference to Staphylococcus haemolyticus.

One hundred and sixty seven isolates of staphylococci isolated from the inpatients of a tertiary care referral hospital in South India were speciated and activity of oxacillin, glycopeptides, linezolid and quinupristin/dalfopristin against these isolates was tested by broth microdilution method. Of the 114 coagulase negative staphylococci (CoNS), 49.1 % were S. haemolyticus, isolated predominantly from urine (64.6%), while the rest belonged to 11 other species. More than half the isolates of S. aureus (52.8%) and 68.4% of the CoNS were oxacillin resistant. All the strains were uniformly susceptible to vancomycin, linezolid and quinupristin/dalfopristin; but 25.6% isolates of S. haemolyticus showed reduced susceptibility to teicoplanin (MIC: 8-16 mg/L). Our study demonstrates the high prevalence of oxacillin resistance among hospital isolates of S. aureus and CoNS in India. Vancomycin, along with the newer agents like linezolid and quinupristin/dalfopristin remains the drug of choice for treating multi drug resistant staphylococcal infections.

Newer antibiotics

To combat the increasing problem of antibiotic resistance, newer antibiotics have been developed or are under development. This review focuses on the newer antibiotics, quinupristin-dalfopristin, linezolid, the newer glycopeptides, daptomycin, the cationic peptides and the newer fluoroquinolones

Synergy of Arbekacin-based Combinations Against Vancomycin Hetero-intermediate Staphylococcus aureus

This study was undertaken to evaluate the in vitro activities of arbekacin-based combination regimens against vancomycin hetero-intermediate Staphylococcus aureus (hetero-VISA). Combinations of arbekacin with vancomycin, rifampin, ampicillin-sulbactam, teicoplanin, or quinipristin-dalfopristin against seven hetero-VISA strains and two methicillin-resistant S. aureus strains were evaluated by the time-kill assay. The combinations of arbekacin with vancomycin, teicoplanin, or ampicillinsulbactam showed the synergistic interaction against hetero-VISA strains. Data suggest that these arbekacin-based combination regimens may be useful candidates for treatment options of hetero-VISA infections.

In vitro activity of linezolid & quinupristin/dalfopristin against Gram-positive cocci.

BACKGROUND & OBJECTIVES: Since the incidence of vancomycin- and methicillin-resistant Gram-positive infections continue to increase, novel antimicrobials such as linezolid and streptogramin may provide new options to treat patients. The aim of this study was to investigate in vitro susceptibility of Enterococcus faecium resistant to glycopeptides, coagulase negative staphylococci and S. aureus resistant to methicillin isolated mainly from blood and also rectal swab cultures of patients against quinupristin/dalfopristin and linezolid. METHODS: The in vitro susceptibility to linezolid and quinupristin/dalfopristin for a total of 332 isolates of Gram-positive cocci [127 methicillin-resistant Staphylococcus aureus, 109 methicillin-resistant coagulase negative staphylococci (71 S. epidermidis, 38 S. haemolyticus) and 96 vanA genotype vancomycin-resistant Enterococcus faecium] was investigated by E test. RESULTS: All MRSA and MRCoNS isolates were susceptible to linezolid (MICs < 4.0 mg/l). Ninety per cent of VRE isolates were inhibited by linezolid at concentration of 2.0 mg/l and presented similar activities to quinupristin/dalfopristin. MICs for quinupristin/dalfopristin against staphylococci were also low (MIC(90) = 1.0 mg/l for both MRSA and MRCoNS isolates). INTERPRETATION & CONCLUSION: The results of the present study demonstrated that quinupristin/ dalfopristin and linezolid, have good in vitro activity against MRSA, MRCoNS and vancomycin resistant E. faecium in Turkey. These drugs could be promising therapeutic options in an era of rapidly growing antibiotic resistance in all parts of world.

Quinupristin/Dalfopristin-induced Sweet's Syndrome

Quinupristin/Dalfopristin is a new combination of streptogramin antibiotics designed specifically to treat clinically significant infections due to Vancomycin-resistant Enterococcus Faecium. Sweet's syndrome is characterized by painful skin plaques, which is associated with dermal neutrophilic infiltration, fever and peripheral blood leukocytosis. Drug-induced Sweet's syndrome has a temporal relationship between drug ingestion, clinical presentation and the temporally-related resolution of lesions following drug withdrawal or on treatment with systemic corticosteroids. A 63-year-old woman received Quinupristin/Dalfopristin for acute pyelonephritis developed fever, arthralgia, vomiting, and painful erythematous skin plaques. A skin biopsy showed neutrophilic dermatosis, and there was rapid resolution of the symptoms and cutaneous lesions after discontinuation of Quinupristin/Dalfopristin, consistent with drug-induced Sweet's syndrome. To date, there has been no reported case of Sweet's syndrome associated with the use of Quinupristin/Dalfopristin.