Search

The region of Coquimbo has the highest percentage of goats (Capra hircus) in Chile and is severely affected by droughts. This can lead to environmental challenges such as limited water and forage availability when goats are kept in natural grasslands. The objective of this study was to assess the welfare of dairy goats in semi-intensive production systems under drought conditions. The study was carried out in La Serena city, region of Coquimbo, Chile and 22 semi-intensive dairy goat farms were assessed using the Animal Welfare Indicators protocol. In each evaluation, the following indicators and information were gathered: physical and behavioural indicators of animal welfare, farmers' sociodemographic information, farm facilities, husbandry practices and management of the farm, and farmers' perception of animal welfare. Of the goats evaluated (n = 446), the vast majority had a body condition score (BCS) considered normal (n = 349; 78.25%). The main welfare problems were poor hair condition, faecal soiling, overgrown claws and improper disbudding or dehorning. The majority of farmers (96%) considered it 'rather important' or 'very important' to handle their goats in a gentle manner, expressing concern about the welfare of their animals and considering pain as a negative experience for goats. A lower than expected percentage of very thin animals (low BCS) were seen, considering the drought conditions and the forage shortage that affects the region, and no animals were observed with signs of thermal stress. The semi-intensive production systems could be an alternative to pasture-based systems to overcome environmental challenges. [ABSTRACT FROM AUTHOR]

El tétanos y el botulismo son dos infecciones graves causadas por las bacterias Clostridium tetani y Clostridium botulinum, respectivamente.

El grupo HACEK (Haemophilus, Aggregatibacter, Cardiobacterium, Eikenella, Kingella) incluye bacterias gramnegativas de crecimiento lento que forman parte de la microbiota del tracto respiratorio superior y genitourinario del ser humano y de los animales.

Los géneros Salmonellay Yersinia, pertenecientes a la familia Enterobacteriaceaey Yersiniaceae, respectivamente, son importantes agentes de zoonosis. Especies incluidas en estos géneros son causantes de cuadros gastrointestinales y sistémicos.

Corynebacterium, Listeriay Bacillusson bacilos Gram positivos aerobios muy ubicuos que colonizan el ambiente, a animales y al hombre. Corynebacterium difteriaeproduce la difteria en sus formas cutánea y respiratoria, enfermedad controlada por vacunación solo en algunos países y con un aumento de incidencia por la inmigración y el rechazo a la vacunación. Listeria monocytogenesse asocia a bacteriemia y meningitis en mujeres embarazadas, neonatos, ancianos e inmunodeprimidos, aunque su incidencia a nivel global aún se desconoce. Bacillus anthracisestá considerado como uno de los potenciales agentes de bioterrorismo por su elevada letalidad. Los síntomas de las distintas formas (cutánea, gastrointestinal y respiratoria) son bastante inespecíficos, de forma que se han desarrollado procedimientos diagnósticos que permitan su detección con una mayor seguridad en caso de sospecha. Las tres especies cuentan con mecanismos de virulencia como la producción de toxinas, la invasividad y supervivencia intracelular, la resistencia en el ambiente y la producción de enzimas líticas de distinto tipo. Otras especies de Corynebacteriumo Bacillusson consideradas patógenos oportunistas y su importancia en la clínica se ha incrementado en las últimas décadas, con el aumento en población inmunosuprimida, así como con la utilización de dispositivos médicos y prótesis, susceptibles de colonización.

The most serious problem related to the use of tunneled catheters in hemodialysis is bacteremia. The aim of this study was to detect hemodialysis catheter colonization and, establish a preemptive therapy based on a catheter antibiotic lock in order to prevent development of catheter-related bloodstream infections. During a 24-month period, all patients with tunneled catheters in our hemodialysis unit were evaluated by extracting a through-catheter leukocyte culture every 15 days. There were 28 episodes of catheter colonization occurring in 13 patients (2.2 colonization episodes per 1000 catheter patient-days). At the time of colonization, catheters had been in place for a mean of 562 days (range: 16 to 1475 days). Coagulase negative staphylococci (CNS) were the most common microorganisms to be isolated. A preemptive therapy consisting in teicoplanin locks (10 mg/mL) for 21 days was able to eradicate catheter colonization in 89% of the cases when CNS were isolated. However, relapse of colonization occurred in 61.2% of these cases. The mean duration of catheter use was 239 days (range: 9 to 483 days) after treatment of a colonization episode. The incidence of catheter-related bloodstream infection in our population was 0.78 episodes per 1000 catheter patient-days (IC 95%: 0.374–1.434). This study shows the utility of intra-catheter leukocyte culture for early detection of hemodialysis catheter colonization. Moreover, it establishes that the eradication of biofilm-related CNS is possible without the removal of the catheter, thus enabling a longer catheter lifespan. (Int J Artif Organs 2008; 31: 820–6)

Microorganisms universally attach to surfaces, resulting in biofilm formation. These biofilms entail a serious problem in daily clinical practice because of the great prevalence of implantable device-related infections. Differences in antibiotic activity against planktonic and sessile bacteria may relate to clinical failures in the treatment of biofilm-related infections (BRI). Bacteriophages have several characteristics that make them potentially attractive therapeutic agents in some selected clinical settings, like for example BRI. They are highly specific and very effective in lysing targeted bacteria, moreover, they appear to be safe for humans. Many studies have shown the potential of phages for the treatment of infectious diseases in plants and animals, including infections with highly drug-resistant bacteria. The therapeutic use of bacteriophages, possibly in combination with antibiotics, may be a valuable approach in BRI. However, many important questions still remain that must be addressed before phages can be endorsed for therapeutic use in humans.

Vascular catheters are the most frequently used indwelling medical devices and have become necessary tools for patients with chronic or critical illness. Surgically or percutaneously placed venous access ports are used to facilitate long-term intravenous therapy. The widespread use of these devices has resulted in a dramatic increase in catheter-related infections. It implies considerable morbidity, occasional mortality, and an increase in medical costs derived from its diagnosis, treatment, and mainly, prolongation of the patient's in-hospital stay. Treatment of such infections is often difficult due to the presence of biofilms on the port inner surface; inside the biofilms, bacteria are less vulnerable to antimicrobial agents. Current diagnostic strategies are suboptimal, and most successful treatment options require removal of the infected device followed by a course of antimicrobial therapy. There are limited data concerning the efficacy of antibiotic treatment of port-related bloodstream infections without catheter removal.

The in vitro effect of nine antibiotic combinations was investigated in Staphylococcus epidermidis biofilms using ATP-bioluminescence for viable bacterial cell quantification. Four slime-producing (SP) strains were used to form biofilms 6, 24 and 48 h old. These biofilms were exposed for 24 h to antibiotics at 4 x, 2 x, 1 x and 0.5 x MIC. Combinations involving tetracycline together with another antibiotic were the most efficient at the biofilm age and concentration range under study. The combination vancomycin-rifampicin produced the highest bactericidal effect on 6 h biofilms at 4 x MIC, but this effect decreased dramatically in older biofilms. To detect possible antibiotic synergy in combinations that had a significant killing effect, antibiotics were studied not only in combination but also individually. Synergic effects were observed in all the combinations tested. Differences between the effect in combination and the sum of individual antibiotic effects (degree of synergy) were significant (mostly P< 0.001) and exceeded 1 log10 cfu/mL in the majority of cases. In 48 h biofilms, antibiotics caused a significant bactericidal effect when applied in combination, but never when used individually. These results indicate that the biofilm test applied allows the detection of synergy between antibiotics and suggests that this assay could be useful in clinical and extensive synergy studies on S. epidermidis biofilms.

Staphylococcus aureusbiofilms formed on medical implants represent a serious problem, being difficult to eradicate with antibiotic therapy and leading to chronic infections. Simplified in vivo and in vitro antibiotic susceptibility assays using biofilm bacteria are needed. In this work, a novel chronic osteomyelitis infection model was developed in rats in the absence of bacterial suspension, requiring the use of only 106bacteria in biofilms at the site of surgery, with a full success in reproducing infection. Stainless‐steel implants pre‐colonized for 12 h with a highly adherent S. aureusisolate were introduced into the rat tibiae. In animals not submitted to antibiotic treatment, infection was found in the implants and spread to bone in all cases, indicating the high efficacy of the model to reproduce osteomyelitis. The effect of a 21‐day treatment with cefuroxime, vancomycin, tobramycin or ciprofloxacin on infection was studied in this model 42 days after surgery. Bone colonization was inhibited by vancomycin and cefuroxime. Cefuroxime (the most efficient antibiotic, able to sterilize 1 out of 8 implants) reduced the number of bacteria in biofilms adhered to implants at a higher extent than vancomycin, trobramycin and ciprofloxacin. Analogous observations were made in this work in vivo and in vitro on the relative antibiotic efficacy against S. aureusbiofilm bacteria, suggesting the usefulness of both tests as a potential tool to study antibiotic suceptibility, and the need for new antimicrobials against these bacteria. © 2001 Orthopaedic Research Society. Punlished by Elsevier Science Ltd. All rights reserved.

Four slime-producing isolates of Staphylococcus aureus were used in an antibiotic susceptibility assay for biofilms developed on 96-well polystyrene tissue culture plates. The study involved 11 antibiotics, two biofilm ages (6 and 48 h), two biofilm growth media (tryptone soy broth (TSB) and delipidated milk) and three antibiotic concentrations (4 x MBC, 100 mg/L and 500 mg/L). ATP-bioluminescence was used for automated bacterial viability determination after a 24 h exposure to antibiotics, to avoid biofilm handling. Under the conditions applied, viability in untreated biofilms (controls) was lower when biofilm growth was attempted in milk rather than in TSB. Various antibiotics had a greater effect on viability when used at higher (> or =100 mg/L) antibiotic concentrations and on younger (6 h) biofilms. Increased antibiotic effect was observed in milk-grown rather than TSB-grown biofilms. Phosphomycin and cefuroxime, followed by rifampicin, cefazolin, novobiocin, vancomycin, penicillin, ciprofloxacin and tobramycin significantly affected biofilm cell viability at least under some of the conditions tested. Gentamicin and erythromycin had a non-significant effect on cell viability. Transmission electron microscopy revealed that cells at the inner biofilm layers tend to remain intact after antibiotic treatment and that TSB-grown biofilms favoured a uniformity of cell distribution and increased cell density in comparison with milk-grown biofilms. A reduced matrix distribution and enhanced cell density were observed as the biofilm aged. The S. aureus biofilm test discriminated antibiotics requiring shorter (3 h or 6 h) from those requiring longer (24 h) exposure and yielded results which may be complementary to those obtained by conventional tests.

1. The aim of the present study was to determine the role of noradrenergic neurotransmission in neuronal activities intracellularly recorded in neocortical slices obtained from rats presenting the gamma-aminobutyric acid (GABA) withdrawal syndrome (GWS), a focal epilepsy consecutive to the interruption of a chronic intracortical GABA infusion into the somatomotor cortex. Neurons recorded in the epileptic focus area (n = 52) were bursting or nonbursting cells. Intrinsic bursting (IB, n = 20) cells presented bursts of action potentials (APs) to an intracellular depolarizing current injection and paroxysmal depolarization shifts (PDSs) to white matter stimulation. Synaptic bursting (SB, n = 22) cells presented only PDSs. Nonbursting (NB, n = 10) cells presented no burst after either synaptic stimulation or depolarizing current injection. Results were compared with those obtained from NB neurons (n = 4) recorded in slices from saline-infused rats. 2. In all of the recorded neurons, bath application of norepinephrine (NE, 10 and 100 microM) provoked a depolarization (1-5 mV) associated with a decrease in input K+ conductance having a mean reversal potential at -90 to -102 mV, not significantly different for bursting and nonbursting cells. This reversal potential differed from that of Cl(-)-mediated inhibitory postsynaptic potentials (-70 mV) elicited in NB cells by electrical stimulation of the white matter. 3. In IB cells, the NE-induced depolarization replaced the intrinsic bursts by a sustained repetitive discharge of single APs and caused intrinsic bursts to appear during previously subthreshold depolarizing current pulses. These NE-increased activities were abolished by dihydropyridine nitrendipine (1 microM) and by Cd2+ (0.5 mM) or Co2+ (2 mM), thus confirming that Ca2+ currents contribute to burst generation in IB cells. 4. In both NB and SB cells recorded in slices from GWS rats, NE provoked the appearance of intrinsic bursts of APs during steps of depolarizing current injections. In addition, in NB cells, NE caused synaptic bursts to appear after white matter stimulation. These NE-induced bursts were dihydropyridine (nitrendipine, 1 microM)- and Cd2+ (0.5 mM)- or Co2+ (2 mM)-sensitive and were related to an increased AP-afterdepolarization. The fast AP-afterhyperpolarization was not affected by NE. In NB cells recorded in slices from saline-infused rats (n = 4) NE did not provoke the appearance of bursts even when stimulation intensity was increased up to three times.(ABSTRACT TRUNCATED AT 400 WORDS)

Summary Ventriculo-peritoneal shunt malfunction may be caused by shunt infection which may not be clinically apparent as the cause of the malfunction by standard diagnostic criteria. This suggests that the real incidence of infected shunts might be higher than previously suspected. In order to study the relationship between infection and shunt malfunction, we followed a protocol over five years (54 V-P shunts) consisting of (1) removal of the malfunctioning shunt and replacement in the same surgical procedure with a new one or institution of an external ventricular drainage for 8 days (if there were clear signs of infection), (2) culturing of CSF and every part of the removed shunt, and (3) intravenous antibiotic treatment (Vancomycin 1g./12h + Ceftriaxone 1g./12h) for five days after the new V-P shunt had been inserted. In those cases in which an external ventricular drainage had been placed, its tip and a portion of the new V-P shunt were also cultured. The results showed that although CSF cultures were negative in 49/54 cases (90.7%), cultures of the removed shunts were positive in 32/54 (59.2%), most of them (21/32, 65.6%) for Staphylococcus coagulase negative organisms.

A rat experimental osteomyelitis model was used to study the efficiency of antibiotics on biofilm bacteria adhered to implants in relation to the efficiency obtainedin vitro.In the osteomyelitis model, 104bacteria of the strain variant used for thein vitrostudies (a slime-producing variant ofStaphylococcus aureus) were inoculated into the rat tibia at surgery, after implanting a stainless steel canula precolonized for 12 h with this strain. After 5 weeks, a 21-day antibiotic treatment was applied (using cefuroxime, vancomycin, or tobramycin). Subsequently, implant and tibia were studied for presence of bacteria. In this osteomyelitis model, cefuroxime inhibited bone colonization and reduced the number of bacteria in metal and bone at a higher degree (P< 0.05) than vancomycin and trobramycin (the latter antibiotic did not have this reduction effect). Thein vitroassay was applied using three concentrations of each antibiotic (8, 100, and 500 μg/ml) and 6-, 24-, and 48-h biofilms. Bacterial viability was evaluated by ATP-bioluminescence after 24 h of antibiotic treatment. In thisin vitroassay, cefuroxime significantly (P< 0.05) reduced in all cases the number of viable bacteria in biofilms, tobramycin did not affect viability, and vancomycin affected viability except at the lowest concentration used (8 μg/ml, i.e., 8× the minimal bactericidal concentration of this antibiotic) when facing the oldest (48 h) biofilm. These results demonstrate the usefulness of the osteomyelitis model applied in providing evidence for a close correlation between thein vitroandin vivofindings on the effect of three antibiotics under study.