Uncommon case of Mycobacterium bovis brain abscess complicated by suppurative fistula, and review of the literature. / Caso insólito de absceso cerebral por Mycobacterium bovis complicado con fístula supurativa y revisión de la bibliografía.

INTRODUCTION: Mycobacterium bovis is an infrequent cause of central nervous system tuberculosis in Spain, with few cases described in the literature. Since compulsory pasteurization of milk and implementation of eradication programs on infected cattle, human sporadic illness with this organism has dramatically declined in developed countries. CASE REPORT: A 71-year-old immunocompromised male, who presented a calvarial lytic lesion. A craniotomy for the total resection of the lesion was performed and the microbiology results were positive for M. bovis, therefore antituberculous therapy was initiated. Despite of the correct treatment, the patient developed a tuberculous abscess that required an aggressive surgical management followed by a suppurative fistula. Based on the treatment of tuberculous lymphadenitis, we decided to perform a conservative management with antituberculous therapy (isoniazid + rifampicin + ethambutol + moxifloxacin + steroids during 12 months) and avoided new surgical cleanings of the surgical bed obtaining a good response and a good clinical evolution. CONCLUSIONS: As far as we know, this is the first case reported of a suppurative fistula after the resection of a cerebral abscess caused by M. bovis, therefore, there is no report in the literature about the treatment of this complication.

TITLE: Caso insólito de absceso cerebral por Mycobacterium bovis complicado con fístula supurativa y revisión de la bibliografía.Introducción. Mycobacterium bovis es una causa infrecuente de tuberculosis del sistema nervioso central en España, del cual existen pocos casos descritos en la bibliografía. Desde la pasteurización obligatoria de la leche y la implementación de programas de erradicación del ganado infectado, la enfermedad esporádica humana con este organismo ha disminuido drásticamente en los países desarrollados. Caso clínico. Varón inmunoafectado de 71 años, que presentaba una lesión lítica esporádica en la calota. Se realizó una craneotomía de la lesión y los resultados de microbiología fueron positivos para M. bovis, por lo que se inició tratamiento con terapia antituberculosa. A pesar del tratamiento correcto, el paciente desarrolló un absceso tuberculoso, que requirió un tratamiento quirúrgico agresivo, seguido de una complicación con una fístula supurativa. Sobre la base del tratamiento descrito para la linfadenitis tuberculosa, se decidió realizar un tratamiento conservador de la fístula supurativa, sin realizar nuevas limpiezas del lecho quirúrgico, y mantener de manera prolongada la terapia antituberculosa (isoniacida + rifampicina + etambutol + moxifloxacino + esteroides durante 12 meses), con lo que presentó una buena evolución clínica. Conclusiones. Hasta la fecha, éste es el primer caso descrito de una fístula supurativa después de la resección de un absceso cerebral causado por M. bovis, por lo que no existe en la bibliografía artículo alguno que describa el tratamiento adecuado de esta complicación.

Spinal cord injury after blunt cervical spine trauma: correlation of soft-tissue damage and extension of lesion.

BACKGROUND AND PURPOSE: In patients with spinal cord injury after blunt trauma, several studies have observed a correlation between neurologic impairment and radiologic findings. Few studies have been performed to correlate spinal cord injury with ligamentous injury. The purpose of this study was to retrospectively evaluate whether ligamentous injury or disk disruption after spinal cord injury correlates with lesion length. MATERIALS AND METHODS: We retrospectively reviewed 108 patients diagnosed with traumatic spinal cord injury after cervical trauma between 1990-2011. Plain films, CT, and MR imaging were performed on patients and then reviewed for this study. MR imaging was performed within 96 hours after cervical trauma for all patients. Data regarding ligamentous injury, disk injury, and the extent of the spinal cord injury were collected from an adequate number of MR images. We evaluated anterior longitudinal ligaments, posterior longitudinal ligaments, and the ligamentum flavum. Length of lesion, disk disruption, and ligamentous injury association, as well as the extent of the spinal cord injury were statistically assessed by means of univariate analysis, with the use of nonparametric tests and multivariate analysis along with linear regression. RESULTS: There were significant differences in lesion length on T2-weighted images for anterior longitudinal ligaments, posterior longitudinal ligaments, and ligamentum flavum in the univariate analysis; however, when this was adjusted by age, level of injury, sex, and disruption of the soft tissue evaluated (disk, anterior longitudinal ligaments, posterior longitudinal ligaments, and ligamentum flavum) in a multivariable analysis, only ligamentum flavum showed a statistically significant association with lesion length. Furthermore, the number of ligaments affected had a positive correlation with the extension of the lesion. CONCLUSIONS: In cervical spine trauma, a specific pattern of ligamentous injury correlates with the length of the spinal cord lesion in MR imaging studies. Ligamentous injury detected by MR imaging is not a dynamic finding; thus it proved to be useful in predicting neurologic outcome in patients for whom the MR imaging examination was delayed.

Severe traumatic head injury: prognostic value of brain stem injuries detected at MRI.

BACKGROUND AND PURPOSE: Traumatic brain injuries represent an important cause of death for young people. The main objectives of this work are to correlate brain stem injuries detected at MR imaging with outcome at 6 months in patients with severe TBI, and to determine which MR imaging findings could be related to a worse prognosis. MATERIALS AND METHODS: One hundred and eight patients with severe TBI were studied by MR imaging in the first 30 days after trauma. Brain stem injury was categorized as anterior or posterior, hemorrhagic or nonhemorrhagic, and unilateral or bilateral. Outcome measures were GOSE and Barthel Index 6 months postinjury. The relationship between MR imaging findings of brain stem injuries, outcome, and disability was explored by univariate analysis. Prognostic capability of MR imaging findings was also explored by calculation of sensitivity, specificity, and area under the ROC curve for poor and good outcome. RESULTS: Brain stem lesions were detected in 51 patients, of whom 66% showed a poor outcome, as expressed by the GOSE scale. Bilateral involvement was strongly associated with poor outcome (P < .05). Posterior location showed the best discriminatory capability in terms of outcome (OR 6.8, P < .05) and disability (OR 4.8, P < .01). The addition of nonhemorrhagic and anterior lesions or unilateral injuries showed the highest odds and best discriminatory capacity for good outcome. CONCLUSIONS: The prognosis worsens in direct relationship to the extent of traumatic injury. Posterior and bilateral brain stem injuries detected at MR imaging are poor prognostic signs. Nonhemorrhagic injuries showed the highest positive predictive value for good outcome.

[Aneurysmal subarachnoid hemorrhage: group of study of cerebrovascular pathology of the Spanish society of neurosurgery management guideline]. / Hemorragia subaracnoidea aneurismática: guía de tratamiento del grupo de patología vascular de la sociedad Española de neurocirugía.

An actualized revision of the most important aspects of aneurismal subarachnoid hemorrhage is presented from the guidelines previously published by the group of study of cerebrovascular pathology of the Spanish Society of Neurosurgery. The proposed recommendations should be considered as a general guide for the management of this pathological condition. However, they can be modified, even in a significant manner according to the circumstances relating each clinical case and the variations in the therapeutic and diagnostic procedures available in the center attending each patient.

[Surgical treatment for spontaneous intracerebral haemorrhage. Part II: infratentorial haematomas]. / Tratamiento quirúrgico de la hemorragia intracerebral espontánea. Parte II:Hemorragia infratentorial.

Surgery plays a mayor role in the management of some patients with cerebellar haematomas, although a universally accepted treatment guideline is lacking. The aim of this study was to review the existing evidence supporting surgical evacuation of the haematoma in this pathology. Without any clinical trial on this field, data derived from clinical series suggest that the level of consciousness, the size of the haematoma, the presence of hydrocephalus and the compression of the posterior fossa CSF containing spaces are the main criteria to decide management. Fourth ventricular compression seems to be the best indicator of the last parameter. Existing bibliography shows that haematomas greater than 4 cm or causing complete obliteration of the fourth ventricle or prepontine cistern need surgical evacuation irrespective of the level of consciousness, as they indicate a significant compression of the brainstem. On the other hand, it seems that haematomas of less than 3 cm and without fourth ventricular compression can be managed conservatively or by means of ventricular drainage if hydrocephalus exists and requires treatment. The management of intermediate sized haematomas is less clear although conservative approach could be adopted in presence of adequate neurological status, with EVD in the case of hydrocephalus with low consciousness level. If the level of consciousness is low despite the treatment of hydrocephalus, or in absence of this latter, haematoma evacuation is indicated. Finally, patients with flaccid tetraplejia and absent oculocephalic reflexes, and those whose age or basal condition precludes an adequate functional outcome are not suitable for aggressive treatment. Moreover, some studies have shown that comatose patients with CT scan evidence of severe brainstem compression present a reduced probability of good outcome. Anyway, management should be decided on an individual basis, as there is no enough evidence to support a strict treatment protocol.

[Prognostic models in severe head injury]. / Modelos pronósticos en el traumatismo craneoencefálico grave.

Severe head injury (SHI) is one of the most important health, social, and economic problems in industrialized countries. Most of the recent studies related to this entity still show pessimistic results, with percentages of mortality and unfavourable outcomes very similar than those reported in the last quarter of century. In order to make predictions for patients with SHI, different "prognostic formulas or models" reviewed in this manuscript, have been developed with the main objective of performing reliable predictions for patients with this pathology. These models are constructed by using a group of "prognostic indicators or factors" and different "prognostic scales" useful for measuring the final outcome. The different "statistical techniques or methods" necessary to develop these prognostic models are also analyzed in this paper.

Severe head injury and the risk of early death.

BACKGROUND: Severe head injury (SHI) is one of the most important health, social and economic problems in industrialised countries. Unfortunately, none of the neuroprotection trials for traumatic brain injury have shown efficacy. One of the reasons for this failure could be the inclusion of patients with high probability of early death. A population-based, retrospective study was conducted to develop a prognostic model for identification of these patients. METHODS: Between January 1987 and August 1999, a total of 895 patients (> or = 15 years of age) with non-missile SHI were studied, in whom a computed tomography scan was carried out within the first 6 h of injury. The association between early death (first 48 h after injury) and independent prognostic factors was determined by logistic regression analysis. A scoring system was also constructed. RESULTS: The early-death rate was 20%. Independent predictors of early mortality after SHI were non-evacuated mass (odds ratio (OR) 65, 95% confidence interval (CI) 11 to 379), diffuse injury IV (OR 25, 95% CI 5 to 112), diffuse injury III (OR 8, 95% CI 3 to 22), flaccidity (OR 7, 95% CI 3 to 15), non-reactive bilaterally mydriasis (OR 6, 95% CI 3 to 12), evacuated mass (OR 4, 95% CI 1 to 11), age > or = 65 years (OR 4, 95% CI 1 to 9), decerebration (OR 3, 95% CI 2 to 7) and shock (OR 3, 95% CI 2 to 6). The prognostic model correctly identified 93% of the patients. CONCLUSIONS: This prognostic model is based on simple clinical and radiological data readily available during the first 6 h after injury and is useful for identification of early death after SHI.

[Magnetic resonance in moderate and severe head injury: comparative study of CT and MR findings. Characteristics related to the presence and location of diffuse axonal injury in MR]. / Resonancia magnética en trauma craneal moderado y grave: estudio comparativo de hallazgos en TC y RM. Características relacionadas con la presencia y localización de lesión axonal difusa en RM.

INTRODUCTION: Cranial CT has been the most extended evaluation means for patients suffering head trauma. However, it has low sensitivity in the identification of diffuse axonal injury and posterior fossa lesions. Cranial MR is a potentially more sensitive test but difficult to perform in these patients, a fact that has hampered its generalised use. OBJECTIVE: To compare the identification capability of traumatic intracranial lesions by both diagnostic tests in patients with moderate and severe head injury and to determine which radiological characteristics are associated with the presence of diffuse injury in MR and their clinical severity. MATERIAL AND METHODS: 100 patients suffering moderate or severe head injury to whom a MR had been performed in the first 30 days after trauma were included. All clinical variables related to prognosis were registered, as well as the data from the initial CT following Marshall et al., classification. The MR was blindly evaluated by two neuroradiologists that were not aware of the initial CT results or the clinical situation of the patient. All lesions were registered as well as the classification following the classification of lesions related to DAI described by Adams et al. CT and MR findings were compared evaluating the sensitivities of each test. Factors related to the presence of diffuse injury in MR were studied by univariate analysis using chi2 test and simple correlations. RESULTS: MR is more sensitive than CT for lesions in cerebral white matter, corpus callosum and brainstem. It also detects a greater number of cerebral contussions. The presence of diffuse axonal injury depends on the mechanism of the trauma, being more frequent in higher energy trauma, specially in traffic accidents. Among the radiological characteristics associated to DAI the most clearly related is intraventricular haemorrhage. The presence of a deeper injury and a higher score in the scales of Adams is associated with a lower score in the GCS and motor GCS, and so with a worse level of consciousness and bigger severity of injury, confirming Ommaya's model.

Complete surgical resection of high-grade astroblastoma with long time survival: case report and review of the literature.

Astroblastoma is a rare glial neoplasm of unknown origin and uncertain prognosis. It usually presents in young adults as a well circumscribed hemispheric mass, often associated with a cystic component. The histological features of astroblastoma are the presence of typical astroblastic perivascular pseudorosettes and perivascular hyalinization. Two different subtypes of astroblastoma have been defined based upon histological characteristics. Prognosis, however, sometimes is in contradiction with the pathological appearance and seems to be more closely related to the grade of surgical resection. We present a new case of a patient with a high-grade astroblastoma with a long survival time, in whom complete surgical resection was confirmed by an early postoperative MRI.

Fasciolosis (liver fluke) of the breast in a male patient: a case report.

Fasciolosis is an uncommon disease in this region, as are parasitic infections of the breast. This report describes a 56-year-old man with a previous history of liver abscess presenting with a painful breast mass. He underwent a mastectomy and is well. The pathological findings revealed chronic granulomatous mastitis with Fasciola spp. ova. The literature on this very rare condition is reviewed.

[Value of serial CT scanning and intracranial pressure monitoring for detecting new intracranial mass effect in severe head injury patients showing lesions type I-II in the initial CT scan]. / Utilidad de la TAC secuencial y la monitorización de la presión intracraneal para detectar nuevo efecto masa intracraneal en pacientes con traumatismo craneal grave y lesión inicial Tipo I-II.

OBJECTIVE: To determine the incidence of pathological and intracranial pressure (ICP) changes during the acute posttraumatic period in severe head injury patients presenting with lesions Types I-II (TCDB classification) in the admission CT scan with the aim of defining the most appropriate strategy of sequential CT scanning and ICP monitoring for detecting new intra-cranial mass effect and improving the final outcome. MATERIAL AND METHODS: 56 patients (ages 15-80 years) consecutively admitted during a 2 years period were included. All had the initial CT scan < 24 hours after injury (mean interval = 150 min), several CT controls within the first days of the course and ICP monitoring after admission. Different epidemiological, clinical and radiological variables were recorded and deterioration defined as the development of sustained ICP over 20 mmHg requiring aggressive medical and/or surgical treatment was considered the dependent variable. Uni and multivariate analyses were made for determining the correlation between different parameters and the occurrence of deterioration and the final outcome as assessed with the GOS. RESULTS: The mean GCS score was 5 and 37% of the patients showed pupillary changes; 52.3% had peritraumatic hypotension-hypoxemia, 16.1% anemia and 12.3% coagulation changes. 50% of the patients showed petechial hemorrhages in the white matter or the brainstem, 66% SAH, 40% HIV, 39.3% brain contusion and 21.4% small extraaxial hematomas. 57.1% of the patients showed CT changes through the acute post-traumatic period consisting of new contusion (26.8% of the cases), growing of previous contusion (68.2%) or previous extraaxial hematoma (10.7%), and generalized brain swelling (10.7%). 64.9% of the patients made a favourable and 35.7% an unfavourable outcome. Overall, 27 (48.9%) patients developed deterioration, 21 (37.5%) with concurrent CT changes and 6 (10.7%) without new pathology as seen by the CT control. The remaining 29 (51.7%) patients in this series did not develop deterioration in spite that 11(19.6%) showed CT changes. The age, the initial score, the occurrence of peritraumatic hypotension-hypoxemia and coagulation disorders did not correlate with the risk of deterioration. By contrast, the presence of contusion at the initial CT scan (p= 0.01) and the occurrence of CT change (only generalized brain swelling, p= 0.003) significantly correlated with the risk of deterioration; in his turn deterioration increased by a factor of 10 (OR = 9.8) the risk of death and 7 out of the 8 patients who died developed intractable intracranial hypertension. The 8 (14.2%) patients requiring surgery showed simultaneous ICP deterioration and CT changes, but another 11 patients in a similar condition could be managed without surgery. With or without ICP deterioration, patients showing CT changes had a worse outcome than those without new pathologies, but the difference did not reach statistical significance, DISCUSSION AND CONCLUSIONS: Over 50% of the patients with initial Type I-II lesions developed new CT changes and nearly 50% showed intracranial hypertension during the acute posttraumatic period. Considering the high incidences of ICP and CT deterioration through the course, along with the absence of strong predictors and the discordances between CT and ICP changes (which were seen in 30.3% of the cases) we recommend ICP monitoring after admission in all patients and serial CT scanning at 2-4, 12, 24, 48 and 72 hours after injury with additional controls as indicated by clinical or ICP changes in all cases. Though it is clear that the presence of severe intra-cranial hypertension significantly increased the risk of death, the small size of the sample in this series prevented to assess to what extent the occurrence of new mass effect and/or raised ICP contributed to the development of moderate and severe disability in the survivors which were mainly due to the occurrence of diffuse axonal injury. Finally, demonstrating that sequential CT scanning and ICP monitoring improve the final outcome in this type of patients would require a prospective randomized trial which is impracticable for different reasons, among them the ethical ones.

[Overview of the recent clinical trials in severe head injury and analysis of their therapeutic failure]. / Revisión de los ensayos clínicos sobre prevención del daño neurológico en el traumatismo crancoencefálico grave y análisis de su fracaso terapéutico.

During the past "Decade of the Brain" several neuroprotective agents have been tested in phase III clinical trials for severe head injury (SHI) but unfortunately none of them significantly improved the outcome of these patients. In contrast to the success achieved by these drugs in animal laboratory studies, the results in terms of neuroprotection in the clinical setting have been disappointing. This paper has been divided in three parts: in the first one, we summarize the pathophysiological mechanisms related to SHI, targeted by the neuroprotective agents. In the second part we review the main clinical trials carried out for SHI to date, and in the third one, we analyze the possible reasons that explain why these agents have failed to show efficacy.

A comparison of different grading scales for predicting outcome after subarachnoid haemorrhage.

BACKGROUND: Most scales used to assess prognosis after subarachnoid haemorrhage (SAH) are based on the level of consciousness of the patient. Based on information from a logistic regression model, Ogilvy et al. developed a new grading scheme (Massachussetts General Hospital (MGH) Scale) which applied a simple scoring method to each prognostic factor considered relevant such as level of consciousness, age, quantity of blood in the first CT scan and size of the aneurysm. The purpose of this study is to introduce a modified version of the MGH scale, built up using factors applicable to every patient suffering SAH, and compare this new scale to the World Federation of Neurological Surgeons scale (WFNS), the Glasgow Coma Scale (GCS) scale for SAH and the MGH scale. METHOD: A series of 442 patients consecutively admitted to Hospital 12 de Octubre between January 1990 and September 2001 with the diagnosis of spontaneous SAH were retrospectively reviewed. Outcome was assessed by means of the Glasgow Outcome Scale measured six months after hospital discharge. Differences between grades of the WFNS, the GCS scale for SAH, the MGH scale and the new scale were computed by chi2 statistics. ROC curves were plotted for the different scales and their areas compared. FINDINGS: Both WFNS and GCS scales fail to present significant differences between most of their grades, while the proposed scale shows a constant inter-grade significant difference in predicting outcome. The proposed scale presents a significantly higher prognostic efficacy in the whole series of patients suffering spontaneous SAH, patients with idiopathic subarachnoid haemorrhage (ISAH) and patients with confirmed aneurysmal SAH. The MGH scale is not applicable to some groups of patients suffering SAH. INTERPRETATION: Grading scales including additional factors to the level of consciousness show higher prognostic efficacy. The proposed modification of the MGH scale makes it applicable to every patient suffering SAH without losing its prediction capability.

Molecular basis of quinolone resistance in Escherichia coli from wild birds.

Nine quinolone resistant (minimal inhibitory concentration [MIC] was > 32 microg/mL for nalidixic acid, > 1 microg/mL for ciprofloxacin) isolates of Escherichia coli have been found in wild birds with septicemia. All of the isolates were aerobactin positive. The mechanisms of resistance were characterised by sequencing the quinolone resistance-determining region (QRDR) of the gyrA, gyrB, parC, and parE genes. Sequence analysis of the gyrA gene in all isolates identified only 1 nucleotide substitution at codon Serine-83 for Leucine-83. Sequence analysis of the gyrB, parC, and parE QRDR genes revealed no mutations in any of the isolates. This study was conducted to determine the importance of these genes in the susceptibility of E. coli strains isolated from wild birds to quinolones.

Oligodendroglioma and multiple sclerosis. A case report.

BACKGROUND: The concurrence of multiple sclerosis (MS) and glioma is uncommon. Approximately 30 cases have been reported, but in only six of them the tumour was pure or mixed oligodendroglioma. The appearance of new neurological symptoms and signs in a patient with multiple sclerosis is usually attributed to a relapse of this disease and neuroradiological studies are not always performed. When done, the finding of a new focal mass lesion is usually interpreted as a pseudotumoural plaque. CASE REPORT: A 37-year-old man was admitted because of partial simple seizures and an enlarging intracranial mass. He had been diagnosed of MS eleven years earlier. A MRI study performed eight years before admission showed a large mass in the right frontal lobe which was thought to be a pseudotumoural plaque. Two years later, he developed simple partial motor seizures that were initially controlled with valproic acid. He remained well until three months before admission, when seizures reappeared with a poor response to valproic acid. A new MRI study showed an heterogeneous right frontal enlarging mass lesion. A primary neoplasm was suspected and a subtotal removal was performed. The pathological diagnosis was oligodendroglioma with a periferic demyelinating area. CONCLUSION: Atypical MRI lesions in a patient with MS must be carefully interpreted. Pseudotumoural plaques have been described both clinically and radiologically to be hardly distinguishable from a tumoural lesion and histological confirmation is often required. The association between MS and glioma is uncommon but it must be kept in mind when a mass lesion develops in a patient with MS.

[Prognostic factors in severe head injury]. / Factores pronósticos en el traumatismo craneoencefálico grave.

The knowledge of the so called prognostic factors or indicators involved in severe head injury (SHI) is an issue of great interest to make predictions about the future of patients with this pathology. Those indicators constitute the basic elements of the different prognostic formulas or models carried out in order to make predictions in SHI. The mentioned models, therefore, will be constructed by a group of variables (prognostic indicators or factors) and several scales (prognostic scales) that are useful for measuring the final outcome of these patients. In this paper we resume, after an exhaustive review of the literature, the knowledge about the prognostic factors related to SHI. These indicators have been classified as follows: clinical, radiological, physiological, and biochemical. Moreover, we have briefly described the prognostic scales more commonly used in SHI.

[The new residency program in neurological surgery in Spain]. / El nuevo programa de residencia en neurocirugía en España.

A new Residency Program in Neurological Surgery has been recently elaborated by the "Comisión Nacional de Neurocirugía" following the requirement of the National Council of Specialities. This new Program, which will replace the one proposed in 1992, has been designed in a similar way as those applied in countries providing the best neurosurgical training. Changes included deal with the definition of the speciality, and the introduction of new rotations,a resident Log Book, a Tutor with a well defined profil and commitments, a structured planning of academic and clinical objectives, a rotation or training in research, and a planning for continuous evaluation of the progress of the resident. It is likely that an appropriate application of the new Program in Spanish neurosurgical units with accreditation for training will result in formation of highly competent neurosurgeons. However, there are new challenges for improving neurosurgical training and the development of our speciality in Spain, as those related with new legislation regulating resident working hours, or some political decisions changing the mechanisms for controlling the number of resident positions per year.

[Comparative microbiological study of fresh and heat-treated yoghurt in an in vivo animal model]. / Estudio microbiológico comparativo de yogur fresco y termizado en un modelo animal in vivo.

In an acute assay, rats fasted for 24 h were sounded with 2 ml of fresh yogurt, sterilised yogurt or distilled water, and sacrificed at 2, 4, 8 and 24 h. They were compared with non-sounded rats. The survival of the lactic bacteria of the yogurt administered in the animals' stomach and intestines was determined, and the bacteria isolated were to the Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus profiles belonging to the strains isolated originally from the yogurt. Counts of the total number of microorganisms that were grown in lactobacilli and lactic streptococci media were also made. Analyses of the different types of resulting colonies in the lactobacilli and lactic streptococci media was performed. No L. delbrueckii subsp. bulgaricus or S. thermophilus were characterized in this acute assay. The statistical analysis of the results did not show significant differences in the log UFC. g-1, of the intestinal microbiota microorganisms of the three groups of animals in any of the times. In a chronic assay, three groups of animals, after 30 days of nourishment ad libitum with either a semisynthetic diet with 10% of fresh yogurt, or with 10% of sterilised yogurt or controls, housed in individual metabolism cells, were sacrificed. The results did not show meaningful differences in the long UFC. g-1 of the intestinal microbiota microorganisms from the three groups of animals in any of the times. In turn, in the study of the different types of colonies resulting in the lactobacilli and lactic streptococci media, no L. delbrueckii subsp. bulgaricus or S. thermophilus were characterised in this chronic assay. The results did not show meaningful differences in the log CFU. g-1 of the intestinal flora microorganisms from the three groups of animals in any of the times. In turn, no L. delbrueckii subsp. bulgaricus or S. thermophilus were characterised in this chronic assay.

Group 1 beta-lactamases of Aeromonas caviae and their resistance to beta-lactam antibiotics.

The contribution of beta-lactamase production to beta-lactam antibiotic resistance was examined in an Aeromonas caviae mutant strain, selected in vitro by cefotaxime and derived from a wild-type strain isolated in our laboratory from crude sewage. Both strains produced beta-lactamase. The mutant strain (AC7m) produced beta-lactamase constitutively, in contrast to the parental strain (AC7), which was inducible by cefoxitin. AC7m was regarded as a mutant from AC7, which over-expressed beta-lactamase. The mutant strain showed a remarkable reduction in sensitivity to most of the beta-lactam antibiotics tested, such as (i) aminopenicillins and their combinations with clavulanic acid and sulbactam, (ii) carboxypenicillins, (iii) ureidopenicillins, and (iv) cephalosporins. This strain remained susceptible to ceftazidime, imipenem, and aztreonam. Isoelectric focusing of sonic extracts revealed that both strains AC7 and AC7m shared a common major beta-lactamase band at pI 6.5. The plasmid DNA assays showed that the beta-lactamases expressed by each A. caviae strain were chromosomally encoded. Based on substrate and inhibitor profiles determined in sonic extracts for AC7 and AC7m, the enzymes displayed on isoelectric focusing at pI 6.5 were assigned to chromosomal Group 1 beta-lactamases. Imipenem would therefore be the appropriate choice for therapy of infections caused by A. caviae beta-lactamase over-expressing mutants.