In Vitro Activity of Pexiganan and 10 Comparator Antimicrobials against 234 Isolates, Including 93 Pasteurella Species and 50 Anaerobic Bacterial Isolates Recovered from Animal Bite Wounds.

Animal bite wounds affect more than 5 million Americans annually, resulting in 300,000 emergency department visits, 10,000 hospitalizations, and an untold number of physician office visits. Various forms of topical therapy are empirically self-employed by many patients prior to seeking medical attention. Pexiganan, a 22-amino-acid synthetic cationic analogue of the peptide magainin II, acts by selectively damaging bacterial cell membranes. We determined the MICs for pexiganan and other antimicrobial agents often used for treatment of bite wounds. Most isolates were from U.S. patients, and ∼10% were from European and Canadian patients. The comparator antimicrobials studied were penicillin, amoxicillin-clavulanate, piperacillin-tazobactam, meropenem, clindamycin, doxycycline, moxifloxacin, ceftriaxone, linezolid, and metronidazole. The MIC90s of pexiganan were 32 µg/ml (against Pasteurella multocida subsp. multocida), 16 µg/ml (P. multocida subsp. septica, Pasteurella canis, and Pasteurella dagmatis), 8 µg/ml (Pasteurella stomatis), 8 µg/ml (Eikenella corrodens), 2 µg/ml (Neisseria weaveri, Neisseria zoodegmatis, and Moraxella canis-Moraxella lacunata group), 16 µg/ml (Bergeyella zoohelcum), 64 µg/ml (Bacteroides pyogenes), 4 µg/ml (Fusobacterium russii), 32 µg/ml (Fusobacterium canifelinum), and 64 µg/ml (Prevotella heparinolytica). The concentration of pexiganan in the cream used was 8,000 µg/ml, more than 60 to 100 times the highest MIC obtained. Pexiganan exhibited a broad range of antimicrobial activity, showing potential for treating animal bite infections. A clinical trial seems warranted.

Identification of Pasteurella canis in a Soft Tissue Infection Caused by a Dog Bite: The First Report in Korea

No abstract available.

Total Synthesis and Antimicrobial Activity of Chlorocatechelin A.

Chlorocatechelin A (1) is a structurally unique microbial siderophore containing two units of 4-chloro-2,3-dihydroxybenzoic acid (CDB) and a characteristic acylguanidine structure. Purification from the microbe culture is not an easy task due to the lability of the acylguanidine and its chelating nature. Here we report the first convergent total synthesis and antimicrobial activity of chlorocatechelin A (1). The bis-acylated arginine was constructed using a Schotten-Baumann reaction whereas the CDB component was synthesized from o-vanillin (8). Condensation with an ornithine derivative synthesized from 1-benzyl d-glutamate was followed by deprotection in basic and neutral conditions to complete the total synthesis. We examined the antimicrobial activity of chlorocatechelin A (1) and found that this siderophore was active against desferrioxamine B (DFB)-sensitive microbes including the fish pathogen Pasteurella piscicida.

Treatments of clinical mastitis occurring in cows on 51 large dairy herds in Wisconsin.

Antimicrobials are frequently used for treatment of bovine mastitis and few studies have examined modern treatment strategies on large US dairy farms. The objective of this study was to describe treatment practices for clinical mastitis occurring in cows on large dairy herds in Wisconsin. Treatments performed on 747 cows experiencing cases of mild, moderate, or severe symptoms of clinical mastitis were recorded on 51 Wisconsin dairy farms. Duplicate milk samples were collected from the affected quarter for microbiological analysis at the onset of clinical mastitis and 14 to 21 d after treatment ended. Cows were treated according to individual farm protocol. Drugs and doses used for treatments were recorded for each case. Among all herds, 5 intramammary (IMM) antimicrobials (amoxicillin, hetacillin, pirlimycin, ceftiofur, and cephapirin) were used to treat cows for clinical mastitis. Of 712 cows with complete treatment data, 71.6% were treated with IMM ceftiofur either solely or combined with other antimicrobials (administered either IMM or systemically). Of cows experiencing severe symptoms of clinical mastitis, 43.8% received IMM treatment concurrent with systemic antimicrobials. Of all cows treated, 23.1% received an additional secondary treatment (either IMM, systemic, or both) because of perceived lack of response to the initial treatment. The majority of IMM treatments were administered to cows with a microbiological diagnosis of no growth (34.9%) or Escherichia coli (27.2%). Half of the cows experiencing cases caused by E. coli were treated using systemic antimicrobials in contrast to only 6.8% of cows experiencing cases caused by coagulase-negative staphylococci. In conflict with FDA regulations, which do not allow extra-label treatments using sulfonamides, a total of 22 cows from 8 farms were treated with systemic sulfadimethoxine either solely or in combination with oxytetracycline. Antimicrobial drugs were used on all herds and many cows received extra-label treatments. Great opportunity exists to improve mastitis therapy on large dairy herds, but use of more diagnostic methodologies is necessary to guide treatments. Farmers and veterinarians should work together to create protocols based on the herd needs considering reduced inappropriate and excessive use of antimicrobials.

A study on ovine pneumonic pasteurellosis: isolation and identification of Pasteurellae and their antibiogram susceptibility pattern in Haramaya District, Eastern Hararghe, Ethiopia.

BACKGROUND: Sheep constitute the second major component of livestock in Ethiopia. However, efficient utilization of this potential resource is hampered by combination of health problems, poor management and feed shortage. Haramaya district is one of the remote settings in Ethiopia where information about the livestock disease is not well documented. Hence this study was conducted to determine the causative agents and their antimicrobial susceptibility pattern of bacterial Pasteurella isolates among pneumonic ovine in Haramaya district, Eastern Hararghe, Ethiopia. RESULTS: Out of 256 samples examined, Pasteurella was isolated in 64 (25%), of which 38 (59.4%) were from lungs and 26 (40.6%) were from nasal cavities. 87.5% of the isolates were Mannheimia haemolytica and 12.5% were Pasteurella multocida. All of the isolates from the lungs were Mannheimia haemolytica whereas 69% of the isolates from nasals cavities were Mannheimia haemolytica. Age and body temperature were significantly associated with Pasteurella isolates from clinic (P < 0.05). Despite diverse in the site of origins, the isolates exhibited uniformity in sensitivity to a majority of the antibacterial agents. The most effective drug was Cholramphenicol (100%) followed by Sulfamethoxazole (89.1%) and Tetracycline (84.4%). Both species were completely resistant to Gentamycin and Vancomycin. CONCLUSION: Mannheimia haemolytica is the most common cause of ovine pneumonic pasteurellosis in the study area. The isolates were susceptible to limited antimicrobial agents. Therefore, the antimicrobial susceptibility test should be conducted before treatment, except for critical cases.

Ceftaroline versus isolates from animal bite wounds: comparative in vitro activities against 243 isolates, including 156 Pasteurella species isolates.

More than 5 million Americans are bitten by animals, usually dogs, annually. Bite patients comprise ∼1% of all patients who visit emergency departments (300,000/year), and approximately 10,000 require hospitalization and intravenous antibiotics. Ceftaroline is the bioactive component of the prodrug ceftaroline fosamil, which is FDA approved for the treatment of acute bacterial skin and skin structure infections (ABSSSIs), including those containing methicillin-resistant Staphylococcus aureus (MRSA). There are no in vitro data about the activity of ceftaroline against Pasteurella multocida subsp. multocida and Pasteurella multocida subsp. septica, other Pasteurella spp., or other bite wound isolates. We therefore studied the in vitro activity of ceftaroline against 243 animal bite isolates. MICs were determined using the broth microdilution method according to CLSI guidelines. Comparator drugs included cefazolin, ceftriaxone, ertapenem, ampicillin-sulbactam, azithromycin, doxycycline, and sulfamethoxazole-trimethoprim (SMX-TMP). Ceftaroline was the most active agent against all 5 Pasteurella species, including P. multocida subsp. multocida and P. multocida subsp. septica, with a maximum MIC of ≤0.008 µg/ml; more active than ceftriaxone and ertapenem (MIC(90)s, ≤0.015 µg/ml); and more active than cefazolin (MIC(90), 0.5 µg/ml) doxycycline (MIC(90), 0.125 µg/ml), azithromycin (MIC(90), 0.5 µg/ml), ampicillin-sulbactam (MIC(90), 0.125 µg/ml), and SMX-TMP (MIC(90), 0.125 µg/ml). Ceftaroline was also very active against all S. aureus isolates (MIC(90), 0.125 µg/ml) and other Staphylococcus and Streptococcus species, with a maximum MIC of 0.125 µg/ml against all bite isolates tested. Ceftaroline has potential clinical utility against infections involving P. multocida, other Pasteurella species, and aerobic Gram-positive isolates, including S. aureus.

Antimicrobial disposition in pulmonary epithelial lining fluid of horses, part II. Doxycycline.

Doxycycline concentrations, following two types of oral administration to horses, in pulmonary epithelial lining fluid (PELF) were examined and compared to plasma concentrations. The oral bioavailability was estimated from plasma concentrations achieved after an intravenous study in two horses. Doxycycline (10 mg/kg) was administered either intragastric or as topdressing to nonfasted horses. Blood samples were collected for drug analysis, before and 11 times after administration during 24 h. PELF samples were collected by a tampon device four times after drug administration and analysed for doxycycline concentrations. Another two horses received doxycycline intravenously at a dose of 3 mg/kg and plasma was taken 14 times during a 24- h period. The oral bioavailability of doxycycline was calculated to 17% after intragastric administration and 6% after topdressing administration in nonfasted horses. The degree of penetration of doxycycline into PELF, as described by AUC(PELF) /AUC(plasma) ratios, was 0.87 after intragastric administration. The results indicate that clinically relevant doxycycline concentrations are possible to maintain in PELF after intragastric administration. Furthermore, if bioavailability could be enhanced for per os administration, doxycycline might be a valuable drug for the treatment of lower airway infections in horses.

Pharmacokinetic-pharmacodynamic integration of orbifloxacin in Japanese quail (Coturnix japonica) following oral and intravenous administration.

The pharmacokinetics of single-dose administration of orbifloxacin were determined in Japanese quail (Coturnix japonica) at dosages of 5 mg/kg intravenous (i.v. n = 12) and 7.5 mg/kg oral (p.o.; n = 5), 10 mg/kg p.o. (n = 5), 15 mg/kg p.o. (n = 12) and 20 mg/kg p.o. (n = 5) via HPLC. Orbifloxacin minimal inhibitory concentrations (MICs) against 22 microbial isolates from various bird species were performed to calculate pharmacodynamic surrogate markers. The concentration-time data were analyzed using a naïve pooled data (NPD) approach and compartmental and noncompartmental methods. Steady-state volume of distribution (Vd(ss)) and total body clearance (Cl) after i.v. administration were estimated to be 1.27 L/kg and 0.60 L/h·kg, respectively. Following 15 and 20 mg/kg p.o. dose, bioavailability was 102% and 117%, respectively. The harmonic mean of the corresponding terminal half-lives (T(1/2) λ(z) ) across all the dose groups was 1.71 h. The C(max) /MIC(90) and AUC(0∞24) /MIC(90) for the 15 and 20 mg/kg p.o. doses were ≥5.22 and ≥8.98, and ≥25.80 and ≥39.37 h, respectively. The results of this study suggest that 20 mg/kg orbifloxacin p.o. would be a rational daily dose to treat susceptible infections in Japanese quail not intended for food consumption. For more sensitive bacterial organisms, 15 mg/kg p.o. may also be effective.

Development and in vitro evaluation of biopolymers as a delivery system against periodontopathogen microorganisms.

Periodontal disease is the major cause of tooth loss in adults. Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans are considered key pathogens in periodontitis. The treatment consists of oral hygiene education, instrumentation for removal of calculus (scaling), chemotherapy and periodontal surgery. Several agents are commercially available; these chemicals can alter oral microbiota and have undesirable side-effects such as vomiting, diarrhea and tooth staining. Hence, the search for alternative products continues and natural phytochemicals isolated from plants used as traditional medicine and the use of biomaterials are considered good alternatives. Chitosan and pullulan are polymers that have been proposed due to their favorable properties such as biocompatibility, biodegradability, and adhesion ability. They can be used as local delivery systems of active principles of plant extracts. Thymus vulgaris, Matricaria chamomilla, Croton lechleri, Calendula officinalis L. and Juliana adstringens Schl. are known to have medicinal activity, and they are used in Mexican traditional medicine. Their extracts were tested in vitro for antimicrobial activity against P. gingivalis and A. actinomycetemcomitans, using agar diffusion and microdilution methods. The antimicrobial activity of films from biopolymers with plant extracts was evaluated by measuring the zones of inhibition against the tested organisms. The aim of this study was to develop bioadhesive films from chitosan and pullulan with added plant extracts and determine the antimicrobial activity of films against periodontal pathogens.

Development and in vitro evaluation of biopolymers as a delivery system against periodontopathogen microorganisms

Periodontal disease is the major cause of tooth loss in adults. Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans are considered key pathogens in periodontitis. The treatment consists of oral hygiene education, instrumentation for removal of calculus (scaling), chemotherapy and periodontal surgery. Several agents are commercially available; these chemicals can alter oral microbiota and have undesirable sideeffects such as vomiting, diarrhea and tooth staining. Hence, the search for alternative products continues and natural phytochemicals isolated from plants used as traditional medicine and the use of biomaterials are considered good alternatives. Chitosan and pullulan are polymers that have been proposed due to their favorable properties such as biocompatibility, biodegradability, and adhesion ability. They can be used as local delivery systems of active principles of plant extracts. Thymus vulgaris, Matricaria chamomilla, Croton lechleri, Calendula officinalis L. and Juliana adstringens Schl. are known to have medicinal activity, and they are used in Mexican traditional medicine. Their extracts were tested in vitro for antimicrobial activity against P. gingivalis and A. actinomycetemcomitans, using agar diffusion and microdilution methods. The antimicrobial activity of films from biopolymers with plant extracts was evaluated by measuring the zones of inhibition against the tested organisms. The aim of this study was to develop bioadhesive films from chitosan and pullulan with added plant extracts and determine the antimicrobial activity of films against periodontal pathogens.

La enfermedad periodontal es la principal causa de perdida de dientes en los adultos. Los agentes causales comunmente identificados con la enfermedad son Porphyromonas gingivalis y Aggregatibacter actinomycetemcomitans. El tratamiento de la enfermedad consiste en educacion sobre higiene oral, remocion de calculos por medio de instrumentacion (raspado y alisado de la raiz), la administracion de medicamentos y cirugia. Hay multiples agentes quimicos disponibles comercialmente; estos pueden alterar la microflora oral y tener efectos secundarios indeseables como vomito, diarrea y pigmentacion dental. Por lo tanto, los productos naturales como los fitoquimicos aislados de plantas que son usadas como medicinas tradicionales y los biomateriales, son considerados buenas alternativas. El quitosan y el pululan son polimeros que han sido propuestos debido a sus propiedades de biocompatibilidad, biodegradabilidad, habilidad de adhesion y que pueden ser usados como sistemas de liberacion de los principios activos de extractos de plantas. Los extractos de Thymus vulgaris, Matricaria chamomilla, Croton lechleri, Calendula officinalis L. y Juliana adstringens Schl. son conocidos por tener actividad medicinal y se usan en la medicina tradicional Mexicana. La actividad antimicrobiana de sus extractos fue probada in vitro contra P. gingivalis y A. actinomycetemcomitans usando los metodos de difusion en agar y de microdilucion. La actividad antimicrobiana de peliculas a base de biopolimeros con extractos de plantas fue evaluada midiendo las zonas de inhibicion de crecimiento de los organismos probados. El proposito de este estudio fue desarrollar peliculas bioadhesivas de quitosan y pululan adicionadas con extractos de plantas y evaluar su actividad antimicrobiana contra periodontopatogenos.

Paleic acid, a fatty acid from Paenibacillus sp.: taxonomy, fermentation, isolation, structure determination, and anti-Mannheimia and -Pasteurella activity.

Paleic acid (1), an antibiotic, was obtained from a fermentation broth of Paenibacillus sp. BMK771-AF3. The compound is a fatty acid (9Z,16R)-16-hydroxy-9-octadecenoic acid ((R)-16-hydroxyoleic acid), whose isolation required protection of its polar functional groups. Mosher esters of paleic acid yielded information on the absolute configuration of secondary alcohol, and well-resolved (1)H NMR peaks around the double bond suggested that olefin adopted a Z geometry. Paleic acid showed potent antibacterial activity and narrow spectrum against Mannheimia haemolytica with MIC values ranging between 0.78 and 1.56 microg ml(-1).

Identification and antimicrobial susceptibility patterns of bacteria causing otitis externa in dogs.

Bacterial agents are considered important pathogens causing external otitis in dogs. It is essential to carry out bacterial culture and antimicrobial susceptibility test in the case of otitis externa, particularly for chronic or recurring cases. Sterile swab samples were obtained from terminal part of vertical ear canals of 74 dogs with otitis externa for cytology, bacterial culture and antimicrobial susceptibility test. Cytologic smears were stained using Gram and Giemsa staining methods. Aerobic bacterial culture performed on blood agar and MacConkey agar. Among total number of 92 isolated bacteria, 68 were Staphylococcus intermedius. Other isolated bacteria included: Pseudomonas aeruginosa, Proteus mirabilis, Escherichia coli, Pasteurella canis, and six other species of coagulase-negative Staphylococcus. Antimicrobial susceptibility test were performed for all isolated bacteria using 14 antibiotics. Based on the results of this study, all isolated Staphylococcus spp. were sensitive to amikacin, enrofloxacin, and rifampin, and had low resistance to gentamicin, cephalothin and ceftriaxone. More than half of gram-positive isolates were resistant to penicillin and ampicillin. Generally, all isolated gram-negative bacteria, were sensitive to amikacin and enrofloxacin, and had low resistance to ceftriaxone and gentamicin. They were highly resistant to penicillin, eythromycin, and cephalothin. Regarding the results of this study, in cases of uncomplicated otitis externa, it is possible to select antimicrobial drugs merely based on cytology, but it is recommended to perform bacterial culture and antimicrobial susceptibility test. However, in complicated or refractory cases, antimicrobials should be selected based on bacterial culture and antimicrobial susceptibility test.

Pharmacokinetics of intravenous ceftiofur sodium and concentration in body fluids of foals.

The objectives of this study were to determine pharmacokinetics of intravenous (i.v.) ceftiofur in foals, to compare ultra-high performance liquid chromatography tandem mass spectometry (UPLC-MS/MS) and microbiologic assay for the measurement of ceftiofur concentrations, and to determine the minimum inhibitory concentration (MIC) of ceftiofur against common equine bacterial pathogens. In a cross-over design, ceftiofur sodium was administered i.v. to six foals (1-2 days-of-age and 4-5 weeks-of-age) at dosages of 5 and 10 mg/kg. Subsequently, five doses of ceftiofur were administered i.v. to six additional foals between 1 and 5 days of age at a dose of 5 mg/kg q 12 h. Concentrations of desfuroylceftiofur acetamide (DCA), the acetamide derivative of ceftiofur and desfuroylceftiofur-related metabolites were measured in plasma, synovial fluid, urine, and CSF by use of UPLC-MS/MS. A microbiologic assay was used to measure ceftiofur activity for a subset of plasma samples. Following i.v. administration of ceftiofur at a dose of 5 mg/kg to 1-2 day-old foals, DCA had a t(1/2) of 7.8 +/- 0.1 h, a body clearance of 74.4 +/- 8.4 mL/h/kg, and an apparent volume of distribution of 0.83 +/- 0.09 L/kg. After multiple i.v. doses at 5 mg/kg, DCA concentrations in CSF were significantly lower than concurrent plasma concentrations. Ceftiofur activity using a microbiologic assay significantly underestimated plasma concentrations of DCA. The MIC of ceftiofur required to inhibit growth of 90% of isolates of Escherichia coli, Pasteurella spp, Klebsiella spp, and beta-hemolytic streptococci was <0.5 microg/mL. Intravenous administration of ceftiofur sodium at the rate of 5 mg/kg every 12 h would provide sufficient coverage for the treatment of susceptible bacterial isolates.

Variation in Pasteurella (Bibersteinia) and Mannheimia spp. following transport and antibiotic treatment in free-ranging and captive Rocky Mountain bighorn sheep (Ovis canadensis canadensis).

Morbidity and mortality associated with respiratory disease following capture and translocation of bighorn sheep (Ovis canadensis canadensis) is a significant concern, particularly when establishing new or augmenting existing bighorn populations. Administration of prophylactic antibiotics at the time of capture is often done to minimize the risk of respiratory disease, but the efficacy of this practice is unknown. The effects of oxytetracycline and florfenicol on the Pasteurella (Bibersteinia) and Mannheimia spp. isolated from samples collected from the oropharynx at the time of capture and 3 or 42 day later were evaluated in two groups of bighorn sheep. The most evident change in the isolation rates or types of Pasteurella (Bibersteinia) spp., Mannheimia spp., or both was an increase of beta-hemolytic strains isolated from bighorn sheep 3 day following oxytetracycline treatment. Both groups of bighorn sheep carried Pasteurella (Bibersteinia) trehalosi identified as the same biovariants, but they did not share biovariants of Mannheimia spp. No animals had signs of respiratory disease. Isolates representative of all biovariants present in cultures from the two bighorn sheep groups were sensitive to in vitro tests to both oxytetracycline and florfenicol and the majority were also sensitive to seven other antibiotics tested. The administration of neither oxytetracycline nor florfenicol eliminated Pasteurella (Bibersteinia) or Mannheimia from the oropharyngeal mucosa. Resistance to either antibiotic used in these animals was not noted. Although the prophylactic benefits of these drugs in preventing disease are uncertain, therapeutic levels of antibiotics in lung tissue during times of stress may reduce the risk of disease. Representative sampling of the oropharyngeal microflora of bighorn sheep source and recipient populations prior to being intermingled should be considered as one of the tools to minimize exposure of naive populations to potentially pathogenic bacteria.