Antibiotic selection in the treatment of acute invasive infections by Pseudomonas aeruginosa: Guidelines by the Spanish Society of Chemotherapy.

Pseudomonas aeruginosa is characterized by a notable intrinsic resistance to antibiotics, mainly mediated by the expression of inducible chromosomic ß-lactamases and the production of constitutive or inducible efflux pumps. Apart from this intrinsic resistance, P. aeruginosa possess an extraordinary ability to develop resistance to nearly all available antimicrobials through selection of mutations. The progressive increase in resistance rates in P. aeruginosa has led to the emergence of strains which, based on their degree of resistance to common antibiotics, have been defined as multidrug resistant, extended-resistant and panresistant strains. These strains are increasingly disseminated worldwide, progressively complicating the treatment of P. aeruginosa infections. In this scenario, the objective of the present guidelines was to review and update published evidence for the treatment of patients with acute, invasive and severe infections caused by P. aeruginosa. To this end, mechanisms of intrinsic resistance, factors favoring development of resistance during antibiotic exposure, prevalence of resistance in Spain, classical and recently appeared new antibiotics active against P. aeruginosa, pharmacodynamic principles predicting efficacy, clinical experience with monotherapy and combination therapy, and principles for antibiotic treatment were reviewed to elaborate recommendations by the panel of experts for empirical and directed treatment of P. aeruginosa invasive infections.

Rose Bengal test: diagnostic yield and use for the rapid diagnosis of human brucellosis in emergency departments in endemic areas.

The aim of the present study was to analyse the diagnostic yield of the rose Bengal test for the rapid diagnosis of human brucellosis in an emergency department in an area where the disease is endemic. The study included 711 patients diagnosed initially with brucellosis and 270 controls. Brucellosis patients were divided into three groups: group I, individuals with no regular exposure to or history of brucellosis; group II, individuals exposed repeatedly to Brucella infection; and group III, individuals infected with Brucella who had received appropriate treatment during the previous 12 months. Blood cultures were positive for 445 (62.6%) brucellosis patients, while the remaining 266 (37.4%) patients were diagnosed according to clinical and serological criteria. The overall sensitivity of the rose Bengal test was 92.9%. The specificities for groups I, II and III were 94.3%, 91.7% and 76.9%, respectively, with positive likelihood ratios of 16.5, 10.4 and 4.2, respectively. The diagnostic gain after the performance of the rose Bengal test was good or very good in patients with no previous exposure to Brucella or history of brucellosis, but poor in patients who were exposed repeatedly to Brucella or had a history of brucellosis and a low pre-test probability. Use of the rose Bengal test as the sole technique for the diagnosis of brucellosis in endemic areas should be considered very carefully in the context of patients who are exposed repeatedly to Brucella or have a history of brucellosis.

Rapid diagnosis of human brucellosis by SYBR Green I-based real-time PCR assay and melting curve analysis in serum samples.

The aim of this study was to develop a LightCycler-based real-time PCR (LC-PCR) assay and to evaluate its diagnostic use for the detection of Brucella DNA in serum samples. Following amplification of a 223-bp gene sequence encoding an immunogenetic membrane protein (BCSP31) specific for the Brucella genus, melting curve and DNA sequencing analysis was performed to verify the specificity of the PCR products. The intra- and inter-assay variation coefficients were 1.3% and 6.4%, respectively, and the detection limit was 5 fg of Brucella DNA (one genome equivalent). After optimisation of the PCR assay conditions, a standard curve was obtained with a linear range (correlation coefficient=0.99) over seven orders of magnitude from 10(7) to 10 fg of Brucella DNA. The LC-PCR assay was found to be 91.9% sensitive and 95.4% specific when tested with 65 negative control samples and 62 serum samples from 60 consecutive patients with active brucellosis. The assay is reproducible, easily standardised, minimises the risk of infection in laboratory workers, and has a total processing time of <2 h. It could therefore form a promising and practical approach for the rapid diagnosis of human brucellosis.

Complications associated with Brucella melitensis infection: a study of 530 cases.

We carried out a prospective study of 530 patients older than 14 years of age with brucellosis. We describe the incidence and clinical features of the focal forms of the disease, analyzing some of the possible factors associated with their appearance. One hundred sixty-nine patients (31.9%) had a focal form or complication. Osteoarticular complications were the most frequent, totaling 113 cases (66%), followed by genitourinary with 18 cases (5.1% of males), hepatic (2.5%), neurologic (1.7%), and heart (1.5%). Nine patients (1.7%) had more than 1 complication. In a multivariate analysis, diagnostic delay greater than 30 days (OR 2.0), ESR > 40 mm/hr (OR 1.9), and levels of alpha-2 globulin > 7.5 g/L (OR 6.8) were statistically significant independent variables associated with the presence of focal forms. Twenty-five patients with complications (14.8%) required surgical treatment. The relapse rate was 3.6% for those patients without complications and 4.1% for patients with focal forms (p > 0.05). However, when therapeutic failure, relapses, and mortality were considered together, the risk of an unfavorable evolution was significantly greater in patients with focal forms (10.6% versus 3.6% in patients without complications; OR 1.9, 95% CI 1.4-7.1, p < 0.005). Given the worse prognosis, knowledge and early diagnosis of the focal forms of B. melitensis infection is especially important.

Surgical treatment for infective endocarditis in elderly patients.

OBJECTIVES: We evaluate the clinical, echographic and prognostic characteristics of infective endocarditis (IE) in a large population of elderly patients, and the results of surgical approach. METHODS: Multicentric, prospective, observational cohort study with 961 consecutive left-sided IE: 356 patients aged ≥65 years were compared with 605 younger. Indications for cardiac surgery, potential surgical risk, time and outcome, were compared. RESULTS: Hospital-acquired endocarditis, comorbidity, renal failure and septic shock were more frequent in elderly, but embolisms were less. Intracardiac destruction and ventricular failure were similar in both groups, but significantly fewer elderly patients underwent cardiac surgery (36% vs 51%; p < 0.01), and this group showed a worse outcome (43.2% of mortality vs 27% in younger; p < 0.01), resulting age as an independent predictor of mortality (OR: 1.02 CI95%: 1.01-1.03). Compared with medical treatment, surgery showed lower percentages of mortality compared with medical treatment (23.3% vs 31.3%; p = 0.03) in younger group, but a high mortality was observed with both procedures (47.6% vs 40.3%; p = 0.1) in the elderly. CONCLUSIONS: Although similar percentages of heart failure and intracardiac complications, increasing age is associated with higher mortality in IE. Lower rates of surgical treatment and a worse outcome after operation are common features in elderly patients.

Healthcare-associated infective endocarditis: an undesirable effect of healthcare universalization.

Invasive medical technology has led to an increase in the incidence of healthcare-associated infective endocarditis (HAIE). A prospective multicentre cohort study was conducted at seven hospitals in Andalusia, Spain, to establish the characteristics of HAIE and to compare them with those of community-acquired infective endocarditis (CAIE). HAIE was defined as either infective endocarditis (IE) manifesting >48 h after admission to hospital, or IE associated with a significant invasive procedure performed in the 6 months before diagnosis. Seven hundred and ninety-three cases of IE were investigated, and HAIE accounted for 127 (16%). As compared with patients with CAIE, patients with HAIE were older (60.1 ± 14.4 years vs. 53.6 ± 17.5 years) and had more comorbidities (Charlson index 3.3 ± 2.3 vs. 1.8 ± 2.3) and staphylococcal infections (58.3% vs. 24.8%). Vascular manipulation was the main cause of bacteraemia responsible for HAIE (63%). Peripheral vein catheter-associated bacteraemia accounted for 32.8% of the catheter-related bacteraemias. In-hospital mortality (44.9% vs. 24.2%) was higher in the HAIE group. Septic shock (OR 2.2, 95% CI 2.9-30.2) and surgery not performed because of high surgical risk (OR 1.6, 95% CI 1.2-20) were independent predictors of mortality in HAIE. The present study demonstrates that HAIE is a growing health problem associated with high mortality. Careful management of vascular devices is essential to minimize the risk of bacteraemias leading to HAIE.

Streptococcus agalactiae left-sided infective endocarditis. Analysis of 27 cases from a multicentric cohort.

SUMMARY OBJECTIVE: To evaluate the current trends in the clinical characteristics and the prognosis of Streptococcus agalactiae infective endocarditis (IE), uncommon disease associated with high mortality. METHODS: Descriptive analysis of 27 cases of a large cohort (961 episodes) of infective endocarditis collected in seven hospitals of Andalusia (Spain) between 1984 and 2008. RESULTS: Native valves were affected in most cases (85. 2%), multiple valves were frequently involved (22.2%). The median age of the patients was 65 (51-76) years (59.3% men), with a comorbidity, according to the Charlson index, of 2.6+/-2.3. The most frequent underlying diseases were diabetes mellitus (25.9%), chronic obstructive pulmonary disease (14.8%), neoplasms (14.8%), urological disorders (11%) and chronic liver disease (11%). Clinical presentation was characterized by rapid worsening (median of 9 (5.7-15) days from onset of symptoms until diagnosis), a high rate of embolisms (37%) and cardiac complications (abscesses, fistulas or valve rupture) - 37% of cases. Surgery was performed in 12 patients (44.4%) and a high mortality (40.7%) was observed. CONCLUSION: S. agalactiae IE is a serious disease with aggressive course and high mortality rate and affects patients with debilitating diseases. We must be alert of the development of complications and consider early valve surgery when it is necessary.

Real time polymerase chain reaction: a new powerful tool for the diagnosis of neurobrucellosis.

BACKGROUND/METHODS: We compared the diagnostic yield of a real time polymerase chain reaction (PCR) assay in cerebrospinal fluid (CSF) samples with conventional microbiological techniques for the diagnosis of neurobrucellosis. Following amplification of a 223 bp sequence specific for Brucella genus, melting curve analysis was performed to verify the specificity of the PCR products. RESULTS: All six patients with neurobrucellosis (three meningitis and three meningoencephalitis) had a positive real time PCR assay, whereas CSF cultures and Wright seroagglutination tests were positive in only two and four cases, respectively. Brucella specific amplicons were easily demonstrated by their characteristic melting temperature in all the real time PCR assays. CONCLUSION: LightCycler based real time PCR assay in CSF samples is more rapid and sensitive than conventional microbiological tests. This technique could be useful for the rapid diagnosis of neurobrucellosis.

Brucella endocarditis: clinical, diagnostic, and therapeutic approach.

Brucella endocarditis is an uncommon focal complication of brucellosis. Presented here are 11 cases of Brucella endocarditis, all managed uniformly. The median duration of symptoms prior to diagnosis was 3 months. Five patients (45%) had underlying valvular damage, and in six (55%) endocarditis involved a normal valve. There was a predominance of aortic involvement (82%) and a high incidence of left ventricular failure (91%). Diagnostic suspicion was essential in order to test blood cultures correctly, which in this series were positive in 63% of the patients. Surgical treatment was undertaken in eight patients (72%), all with aortic involvement and left ventricular failure impossible to control with medication. One patient died during the immediate postoperative period. All the other patients received antibiotic therapy for 3 months, with no signs of relapse of the infection or malfunction of the prosthesis during a minimum follow-up period of 24 months.

Osteoarticular complications of brucellosis.

Two hundred and sixty three patients with a diagnosis of brucellosis between January 1984 and December 1987 were studied prospectively. Sixty five patients (25%) developed osteoarticular complications. These patients had a more prolonged course than those with no complications. Spondylitis in 38 (58%) and sacroiliitis in 29 (45%) were the most prevalent. There were no significant laboratory, serological, or bacteriological differences between patients with and without osteoarticular complications. At diagnosis 47 patients (72%) showed radiographic abnormalities, commonly in axial sites but rarely in peripheral sites. Radionuclide bone scan was positive with no radiographic abnormalities in 17 (26%) of cases. Fifty seven patients received medical treatment alone, 51 (89%) being cured with a single course of treatment. Treatment failed or there was a relapse in six patients (11%), of whom five had spondylitis. Eight of the 65 patients (12%), all of whom had spondylitis and paravertebral or epidural abscesses, also required surgical treatment.

Phagocytic cell function in active brucellosis.

In this study, we analyzed phagocytic cell function in 51 patients with active brucellosis and its relationship with different clinical, serological, and evolutionary variables. A control group was made up of 30 blood donors of similar geographic extraction, age, and sex, with no previous history of brucellosis or known exposure ot the infection or specific antibodies. The investigations were carried out at the time of diagnosis, at the conclusion of treatment, and after 6 months of follow-up. Polymorphonuclear leukocyte adherence and nitroblue tetrazolium reduction in response to Brucella antigen were significantly increased in the patients at the time of diagnosis with respect to the control group. In contrast, chemotaxis in response to Brucella antigen and phagocytosis were significantly reduced in the patients with respect to the control group. The alterations in phagocytic cell function were greater in patients with bacteremia, with focal forms of the disease, or with a longer diagnostic delay. Most of these initial alterations tended to normalize with treatment, indicating their transient character.

[Combined use of rose Bengal and indirect immunofluorescence in the diagnosis of brucellosis]. / Empleo combinado del rosa de Bengala e inmunofluorescencia indirecta en el diagnóstico de la brucelosis.

In the present prospective study we have evaluated the sensitivity, specificity and predictive value of the Bengal rose and indirect immunofluorescence (IIF) in 122 patients with a bacteriological diagnosis of brucellosis. The sensitivity of the Bengal rose was 95.79% and its specificity 98.43%. IIF had a sensitivity of 68.80% and a specificity of 100% when the polyvalent anti-IgS conjugate was used. The combined parallel use of Bengal rose and IIF-IgS resulted in a sensitivity of 89.17% and a specificity of 100%. There was a good correlation between Bengal rose and serum agglutination test (r = 0.72); on the contrary, there were not good correlations between the fluorescent conjugates and Bengal rose, agglutination and Coombs test. In conclusion, the combined use of Bengal rose as a screening test and IIF as a confirmation study is a good diagnostic strategy for human brucellosis.

Serology, clinical manifestations and treatment of brucellosis in different age groups.

We prospectively studied 339 patients diagnosed of brucellosis over a six year period in order to evaluate the clinical and serological characteristics of brucellosis in the elderly. 319 patients (94.1%) were under 65 years of age (group A), and 20 patients (5.9%) were older than 65 (group B). No patient in group B developed splenomegaly as opposed to 69 (21.6%) in group A (p less than 0.05). The percentage of positive blood cultures (Brucella melitensis isolated in all cases) was 72.1% in group A and 60% in group B. The mean titer of IgM antibodies measured by indirect immunofluorescence test was significantly lower in the elderly patients, with no other differences in serologic response between the two groups. 103 patients (32.2%) in group A and seven patients (35%) in group B developed some complications; spondylitis was more common and severe among group B patients. There was no therapeutic failure or relapse among patients over 65. We conclude that clinical, bacteriological and serological characteristics and the outcome of brucellosis in the elderly are similar to those seen in younger patients.

Diagnostic yield of a PCR assay in focal complications of brucellosis.

In order to evaluate the diagnostic yield of a PCR assay for patients with focal complications of brucellosis, we studied by PCR and by conventional microbiological techniques 34 nonblood samples from 32 patients with different focal forms of brucellosis. The samples from patients with brucellosis were paired to an equal number of control samples from the same locations of patients whose illnesses had different etiologies. Thirty-three of the 34 nonblood samples (97%) from the brucellosis patients were positive by PCR, whereas Brucella spp. were isolated from only 29.4% of the conventional cultures. For 11.4% of the patients, the confirmatory serological tests were either negative or showed titers below the diagnostic range. Two patients (6.2%) from the control group, both with tuberculous vertebral osteomyelitis, had a positive PCR result. The brucella PCR of blood from these two patients was also positive, and the two strains of Mycobacterium tuberculosis isolated were analyzed by the brucella PCR, with no evidence of amplification. These results show that the PCR assay is far more sensitive than conventional cultures, and this, coupled with its speed and reduction in risk to laboratory workers, makes this technique a very useful tool for the diagnosis of focal complications of brucellosis.

[Evaluation of the Chromotitre EIA test in the diagnosis of human brucellosis]. / Valoración de la prueba Chromotitre EIA en el diagnóstico de la brucelosis humana.

BACKGROUND: The aim of the study was to evaluate the diagnostic efficacy of Chromotitre EIA test for the diagnosis of human brucellosis and compare the same with other classical serologic test. METHODS: A prospective study was performed in 50 patients with active brucellosis. Thirty blood donors, 64 patients with different neoplastic and autoimmune infectious processes, 20 patients with history of brucellosis and 8 subjects with continuous exposure to Brucella at work were analyzed as the control group. RESULTS: Forty-five patients with brucellosis (90%) presented a positive IgM or IgG ELISA, 32 (62%) only IgM, 34 (68%) only IgG and 22 (44%) both immunoglobulins were positive. The sensitivity and specificity of ELISA test jointly evaluating IgM and IgG was 90 and 68%, respectively with these numbers being 62 and 98% and 68% and 38% for ELISA IgM and ELISA IgG. A moderate correlation was found between ELISA IgM with Bengal's Rose test (r = 0.53, p = 0.003) and sero-agglutination (r = 0.63, p = 0.0001) and ELISA IgG with the Coombs test (r = 0.55, p = 0.003). Only acceptable concordance was observed between ELISA IgM and sero-agglutination (kappa = 0.55, p = 0.0001). CONCLUSIONS: The ELISA test evaluated was very useful for the detection of IgM antibodies but was found to be insufficient with respect to IgG antibodies. Despite the slight diagnostic efficacy of the ELISA IgG the combined parallel use of both immunoglobulins achieved a performance similar to that achieved with the classical tests.

Posttreatment follow-Up of brucellosis by PCR assay.

In order to evaluate the usefulness of a peripheral blood PCR assay in the posttreatment follow-up of brucellosis, a cohort of 30 patients was studied by means of blood cultures, rose Bengal, seroagglutination, Coombs' antibrucella tests, and PCR assay at the time of diagnosis, at the end of treatment, and 2, 4, and 6 months later. Of the 29 patients whose PCR assays were initially positive, 28 (96.5%) were negative at the conclusion of the treatment. PCR was positive for the two patients who had relapses and negative for another four who had suspected but unconfirmed relapses. PCR was negative for 98.3% of the follow-up samples from those patients who had a favorable evolution. In conclusion, PCR appears to be a very useful technique, not only for the initial diagnosis of the disease, but also for posttreatment follow-up and the early detection of relapses.

High mortality related with Staphylococcus aureus bacteremia after liver transplantation.

The aim of the present study was to analyze the characteristics of bacteremia occurring in liver-transplant patients in Andalusia, Spain, during the 1990s. At the three participating hospitals, 405 liver transplantations were performed during the study period, and 119 bacteremic episodes were observed following 91 of them (22.4%, 29.4 episodes/100 liver transplants). Gram-positive organisms were the predominant bacteria isolated in cases of early-onset bacteremia (70.7%, P=0.04). The most common sources of bacteremia were the abdomen (33.6%) and intravascular catheters (22.7%), but frequently the source of bacteremia was unknown (31.9%). Mortality at 30 days was 21%. Isolation of Staphylococcus aureus was the only independent risk factor for mortality (relative risk, 3.13; 95% confidence interval, 1.3-7.5; P=0.01). These results indicate that control measures are required in order to reduce the incidence of gram-positive bacteremia and catheter-related infection in this patient population. The observed etiology must be considered when empirical antimicrobial therapy is indicated while awaiting blood-culture results.

Tuberculous vertebral osteomyelitis in the new millennium: still a diagnostic and therapeutic challenge.

In order to determine the clinical features and current prognosis of tuberculous vertebral osteomyelitis, the charts of all patients diagnosed with definite or probable tuberculous vertebral osteomyelitis from January 1983 to June 2002 ( n=78) were reviewed. The mean delay to diagnosis was 6.1 months. Sixty-five (83.3%) patients had inflammatory spinal pain, 35 (44.9%) had some neurological deficit, and only 27 (34.6%) had fever. Paravertebral, epidural, and psoas abscesses were detected in 73.1, 65.4, and 24.4% of the cases, respectively. Culture was positive in 48% of the percutaneous biopsies and in 61.7% of the open biopsies. After histological findings were included, the diagnostic yield of percutaneous biopsies was 68%. Fifty-five (70.5%) patients required surgical treatment at some stage of the disease. Although no deaths were directly attributable to tuberculous vertebral osteomyelitis and only 5.1% of patients relapsed, the mean overall hospital stay was 69.1+/-36.9 days, and 30 (38.5%) patients had severe functional sequelae. In conclusion, diagnosis of tuberculous vertebral osteomyelitis requires a high degree of suspicion. Percutaneous biopsy should be undertaken as soon as possible in any patient with compatible symptoms or radiological images in order to initiate suitable therapy.

Pyogenic, tuberculous, and brucellar vertebral osteomyelitis: a descriptive and comparative study of 219 cases.

OBJECTIVES: To describe a large series of patients with vertebral osteomyelitis (VO), and to compare the clinical, biological, radiological, and prognostic features of pyogenic (PVO), tuberculous (TVO), and brucellar vertebral osteomyelitis (BVO). METHODS: A retrospective multicentre study, which included 219 adult patients with VO with confirmed aetiology, who were diagnosed between 1983 and 1995 in two tertiary care centres. Of these patients, 105 (48%) had BVO, 72 (33%) PVO, and 42 (19%) TVO. RESULTS: One hundred and forty eight (67.6%) patients were male and 71 (32.4%) female. The mean (SD) age was 50.4 (16.4) years (range 14-84) and the mean (SD) duration of symptoms before the diagnosis was 14 (16.8) weeks. In 127 patients (57.9%) the vertebral level involved was lumbar, in 70 (31.9%) thoracic, and in 16 (7.3%) cervical. One hundred and nineteen patients (54.4%) received only medical treatment and 100 (45.6%) required both medical and surgical treatment. The presence of diabetes mellitus, intravenous drug abuse, underlying chronic debilitating diseases or immunosuppression, previous infections, preceding bacteraemia, recent vertebral surgery, leucocytosis, neutrophilia, and increased erythrocyte sedimentation rate (ESR) were significantly associated to PVO. A prolonged clinical course, thoracic segment involvement, absence of fever, presence of spinal deformity, neurological deficit, and paravertebral or epidural masses, were significantly more frequent in the group of TVO. The need for surgical treatment and the presence of severe functional sequelae were more frequent in the groups of PVO and TVO. CONCLUSION: There are significant clinical, biological, radiological, and prognostic differences between BVO, PVO, and TVO. These differences can point to the causal agent and orient the initial empirical medical treatment while awaiting a final microbiological diagnosis.