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Biomedical subjects

M A Domínguez

Publications and source records attributed to M A Domínguez.

At least 19 recordsLinked to original sources
PubMed2006

Respiratory system of Gluconacetobacter diazotrophicus PAL5. Evidence for a cyanide-sensitive cytochrome bb and cyanide-resistant cytochrome ba quinol oxidases.

In highly aerobic environments, Gluconacetobacter diazotrophicus uses a respiratory protection mechanism to preserve nitrogenase activity from deleterious oxygen. Here, the respiratory system was examined in order to ascertain the nature of the respiratory components, mainly of the cyanide sensitive and resistant pathways. The membranes of G. diazotrophicus contain Q(10), Q(9) and PQQ in a 13:1:6.6 molar ratios. UV(360 nm) photoinactivation indicated that ubiquinone is the electron acceptor for the dehydrogenases of the outer and inner faces of the membrane. Strong inhibition by rotenone and capsaicin and resistance to flavone indicated that NADH-quinone oxidoreductase is a NDH-1 type enzyme. KCN-titration revealed the presence of at least two terminal oxidases that were highly sensitive and resistant to the inhibitor. Tetrachorohydroquinol was preferentially oxidized by the KCN-sensitive oxidase. Neither the quinoprotein alcohol dehydrogenase nor its associated cytochromes c were instrumental components of the cyanide resistant pathway. CO-difference spectrum and photodissociation of heme-CO compounds suggested the presence of cytochromes b-CO and a(1)-CO adducts. Air-oxidation of cytochrome b (432 nm) was arrested by concentrations of KCN lower than 25 microM while cytochrome a(1) (442 nm) was not affected. A KCN-sensitive (I(50)=5 microM) cytochrome bb and a KCN-resistant (I(50)=450 microM) cytochrome ba quinol oxidases were separated by ion exchange chromatography.

Bacterial Proteins↗
PubMed2004

Staphylococcus aureus nasal carriage in patients on haemodialysis: role of cutaneous colonization.

We performed a prospective study of Staphylococcus aureus nasal carriage in patients on chronic haemodialysis to determine the role of cutaneous colonization in the aetiology of recurrent nasal colonization. From February 2000 to September 2001, 71 patients on chronic haemodialysis in the dialysis unit at a university hospital were screened monthly for S. aureus nasal carriage. Carriers received nasal mupirocin for five days and were tested for nasal and cutaneous carriage two days later and monthly thereafter. Using genotyping results, recurrence was defined as relapse if pretreatment and subsequent nasal isolates were clonally identical; if the isolates were different, it was considered recolonization. Thirty-nine patients (55%) were nasal carriers: 11 initially and 28 during follow-up. Among the mupirocin-treated patients, the eradication of S. aureus nasal carriage rate was 88.5%. Nasal recurrence was documented in 17 patients (43.5%), and S. aureus nasal strains were available for molecular typing in 14 patients with a total of 23 recurrence episodes. On the basis of pulsed-field gel electrophoresis analysis, 16 (70%) recurrence episodes were considered relapses and seven were considered (30%) recolonizations. Among the episodes of relapse, prior cutaneous colonization was detected in only three cases. In haemodialysis patients, the majority of nasal carriage recurrences after mupirocin therapy were due to relapses. Cutaneous colonization does not appear to be relevant in the development of these relapses.

Anti-Bacterial Agents↗
PubMed2004

[Neutropenia and fever in the patient with cancer].

Infection in the immunocompromised host is a serious clinical situation due to its high morbi-mortality and is one of the most frequent complications in the patient with cancer. In patients treated with chemotherapy, the risk of infection basically depends on the duration and intensity of the neutropenia. It is essential to evaluate, the most probable pathogen involved to initiate, a priori, the most suitable treatment, and also to evaluate the general clinical situation of the patient, because from the very beginning the treatment is quite aggressive. Outpatient care is possible for patients at "low risk" of complications. By evaluating the antecedents and clinical history of the patient, through physical exploration and from the data of laboratory and radiological explorations these points can be acknowledged. The early start of broad spectrum antibiotherapy is crucial, and in this chapter we review the most recent therapeutical recommendations.

Clinical Protocols↗
PubMed2004

[Malign obstruction of the superior vena cava].

The present paper offers a review of the malign syndromes of the superior vena cava, their clinical expressions related to the anatomical characteristics of the compartment where the superior vena cava runs, the diagnostic requirements for realising treatment under the best conditions and the ensemble of measures that must be adopted in dealing with this.

Humans↗
PubMed2004

[Acute dysphagia of oncological origin. Therapeutic management].

Dysphagia is one of the most frequent syndromes in patients with tumours of the head and neck, and the oesophagus. This can be the initial symptom or, more frequently, related to the oncological treatment. We review the most important therapeutic and physio-pathological aspects of acute dysphagia of oncological origin. Deglutition is a complex process in which numerous muscular-skeletal structures intervene under the neurological control of different cranial nerves. The complex neuro-muscular coordination needed for a correct deglutition can be affected by numerous situations, both from the effect of the tumours and from their treatment, basically surgery or radiotherapy. In conclusion, it can be affirmed that for a suitable treatment of oncological dysphagia, a correct initial evaluation and an active treatment are required, since not only the patient's quality of life but, on numerous occasions, the possibility of continuing the treatment and thus maintaining the possibilities of a cure depend on control of the dysphagia.

Acute Disease↗
PubMed2004

[Medullar compression].

Medullar compression is an oncological and neurological emergency, whose diagnosis and early treatment are key factors for avoiding severe and irreversible neurological damage. Paralysis, loss of consciousness and alteration in control of the sphincters are the final consequence of the process, and represent an important source of morbidity of the oncology patient, besides being related to a shorter time of survival. The invasion of the vertebral body by haematogenous dissemination is the most frequent cause of medullar compression. On occasions it can create mechanical vertebral instability which represents a real orthopaedic emergency. Pain is the earliest and most frequent symptom. The signs and symptoms appear to the degree that the process advances, passing through motor weakness, alterations in consciousness until paralysis and incontinence of the sphincters are reached, as a result of complete neurological damage. Clinical history and physical exploration should lead to suspicion about the level at which medullar compression is developing, and the most important complementary exploration is MR of the entire spine, which should be requested immediately in order to decide on starting treatment. Treatment is individualised and must be started early. In general, corticoids in combination with radiotherapeutic oncological treatment and/or surgery are the therapeutic weapons to employ.

Humans↗
PubMed2003

Assessment of Acinetobacter baumannii susceptibility to antiseptics and disinfectants.

Disinfection and antisepsis are of primary importance in controlling outbreaks of Acinetobacter baumannii, a nosocomial pathogen that frequently shows multiple antibiotic resistance. In this study we assessed the susceptibility of nine A. baumannii strains isolated during a sustained intensive care unit outbreak, to several antiseptics and disinfectants based on European Standards. While the tested strains showed diverse antibiotic resistance patterns, they were equally sensitive to the biocides assessed in vitro. We observed neither evidence of development of resistance to biocides over time, nor a correlation between resistance to antibiotics and a decreased susceptibility to antiseptics or disinfectants.

Acinetobacter Infections↗
PubMed2002

Short-term effect of the application of selective decontamination of the digestive tract on different body site reservoir ICU patients colonized by multi-resistant Acinetobacter baumannii.

The effect of a selective decontamination of the digestive tract (SDD) regimen including polymyxin and tobramycin on several body site reservoirs was compared between a test group and a control group in intensive care unit (ICU) patients with faecal multi-resistant Acinetobacter baumannii colonization. SDD significantly reduced faecal and pharyngeal carriage when compared with the control group at the end of ICU stay (48% versus 91%, P = 0.001, and 38.5% versus 78%, P = 0.01, respectively), but failed to reduce axillary colonization (75% versus 78%, P = 0.6). In addition, the isolation of A. baumannii from new clinical samples was lower in patients with SDD (45.5% versus 81%, P = 0.05). No resistance to polymyxin was observed. We conclude that the digestive tract reservoir of A. baumannii in ICU patients may be decreased by a SDD regimen.

Acinetobacter↗
PubMed2001

Molecular epidemiological typing of Enterobacter cloacae isolates from a neonatal intensive care unit: three-year prospective study.

Since 1992, there has been an increase in the incidence of Enterobacter sepsis in the neonatal intensive care unit (NICU) of the authors' hospital. From 1995 to 1997, a prospective molecular epidemiological survey of the colonizing and infecting strains isolated from neonates was conducted. Enterobacter cloacae was the most frequent cause of neonatal sepsis, accounting for 19.2% of all neonatal infections, reaching a peak incidence of 2.2/1000 during 1996. Fifty isolates from the NICU and four epidemiologically unrelated strains were characterized by pulse-field gel electrophoresis (PFGE), ribotyping, enterobacterial repetitive intergenic consensus (ERIC)-PCR and plasmid profiling. PFGE was the most discriminatory technique and identified 13 types (two of them classified into two and three subtypes) compared with ERIC-PCR, plasmid profiling and ribotyping that identified 11, 11 and seven types, respectively. A good correlation was found between all techniques. Five different clones caused 15 cases of sepsis. Clones A and B were prevalent in 1995 and 1996, but they were not isolated in 1997. An outbreak caused by clone G in 1997 was controlled by cohort nursing and hygienic measures, without changing the antibiotic policy. Strains were characterized by their antibiotic resistance pattern and divided into three groups. Group I correlated with PFGE types A, B1 and B2, which hyperproduced Bush type 1 chromosomal beta-lactamase and expressed extended-spectrum ?-lactamases (ESBLs). Group II only hyperproduced Bush type 1 chromosomal beta-lactamase and correlated with PFGE-types D1, D2, D3 and I. Finally, Group III, with inducible beta-lactamases, correlated with the rest of PFGE types. The sudden disappearance of E. cloacae after reinforcement of hygienic measures confirms the importance of patient-to-patient transmission.

Bacterial Typing Techniques↗
PubMed2000

Chemoradiotherapy for muscle invading bladder carcinoma. Final report of a single institutional organ-sparing program.

PURPOSE: Chemoradiotherapy is becoming an alternative to radical cystectomy among patients with muscle invading bladder cancer. We began a prospective study in 1988 to determine the possibilities of conservative treatment and aiming to improve the results obtained by cystectomy alone in invasive bladder cancer. A combination of methotrexate, vinblastine, adriamycin, and cisplatin (M-VAC), followed by radiotherapy and concomitant cisplatin was used. METHODS: Fifty patients with good performance status and with stages T2 to T4 operable untreated invasive bladder cancer were entered in the study. Treatment protocol was as follows: (i) cytoreductive transurethral resection; (ii) two cycles of M-VAC chemotherapy; (iii) radiotherapy, 45 Gy on pelvic volume and, at the same time, 20 mg/m(2) cisplatin on days 1 to 5. Cystoscopic evaluation: if there was a complete response, radiotherapy was completed up to 65 Gy; if there was not a complete response, a cystectomy was performed. Median follow-up of the series was 73 months (18-180 m). RESULTS: Tumor response was as follows: 34 complete responses (68%), 9 partial responses (18%), and 7 nonresponses (14%) were observed. The 5-year overall survival and local control were 48% and 47%, respectively. For the complete responder patient, 5-year survival and local control were 65% and 70%, respectively. Severe toxicity was uncommon. The most frequent were leucopenia and cystitis. No treatment-related deaths occurred with either treatment protocol. CONCLUSIONS: Conservative combination treatment may be an acceptable alternative to immediate cystectomy in selected patients with bladder cancer, although a randomized clinical trial would be required to produce definitive results.

Aged↗
PubMed2000

PCR-based DNA fingerprinting (REP-PCR, AP-PCR) and pulsed-field gel electrophoresis characterization of a nosocomial outbreak caused by imipenem- and meropenem-resistant Acinetobacter baumannii.

OBJECTIVE: To demonstrate the usefulness of REP-PCR and AP-PCR on molecular typing of A. baumannii isolates. METHOD: From February to November 1997, 29 inpatients at Ramón y Cajal Hospital, Madrid-23 in five intensive care units (ICUs) and six at two different medical departments-were either colonized or infected with imipenem- and meropenem-resistant Acinetobacter baumannii (IMRAB) strains (MICs of 64-256 mg/L). A wide antibiotic multiresistance profile was observed with IMRAB strains, and only tobramycin, sulbactam and colistin displayed valuable activity. For typing IMRAB isolates, repetitive extragenic palindromic sequence-based polymerase chain reaction (REP-PCR) and arbitrary primer sequence-based polymerase chain reaction (AP-PCR) methods were used and compared with pulsed-field gel electrophoresis (PFGE) as reference technique. For comparative purposes, 30 imipenem- and meropenem-susceptible A. baumannii (IMSAB) strains isolated before, during and after the outbreak were included in this study. RESULTS: The molecular typing results showed that the outbreak was caused by a single IMRAB strain (genotype 1). On the other hand, seven different genotypes were observed in the pre-, at- and post-outbreak strains tested by REP-PCR. Regarding AP-PCR, three of four at-outbreak IMSAB strains were indistinguishable from the IMRAB profile. Thus, with AP-PCR, only six genotypes were obtained, apart from the IMRAB genotype. CONCLUSION: Under our experimental conditions, REP-PCR had a higher discriminatory power than AP-PCR, with PFGE as reference technique. The REP-PCR technique is a useful and expeditious method for the epidemiologic characterization of A. baumannii nosocomial outbreaks, the results being comparable to those obtained with the PFGE technique.

Acinetobacter↗
PubMed2000

Emergence and rapid spread of carbapenem resistance during a large and sustained hospital outbreak of multiresistant Acinetobacter baumannii.

Beginning in 1992, a sustained outbreak of multiresistant Acinetobacter baumannii infections was noted in our 1,000-bed hospital in Barcelona, Spain, resulting in considerable overuse of imipenem, to which the organisms were uniformly susceptible. In January 1997, carbapenem-resistant (CR) A. baumannii strains emerged and rapidly disseminated in the intensive care units (ICUs), prompting us to conduct a prospective investigation. It was an 18-month longitudinal intervention study aimed at the identification of the clinical and microbiological epidemiology of the outbreak and its response to a multicomponent infection control strategy. From January 1997 to June 1998, clinical samples from 153 (8%) of 1,836 consecutive ICU patients were found to contain CR A. baumannii. Isolates were verified to be A. baumannii by restriction analysis of the 16S-23S ribosomal genes and the intergenic spacer region. Molecular typing by repetitive extragenic palindromic sequence-based PCR and pulsed-field gel electrophoresis showed that the emergence of carbapenem resistance was not by the selection of resistant mutants but was by the introduction of two new epidemic clones that were different from those responsible for the endemic. Multivariate regression analysis selected those patients with previous carriage of CR A. baumannii (relative risk [RR], 35.3; 95% confidence interval [CI], 7.2 to 173.1), those patients who had previously received therapy with carbapenems (RR, 4.6; 95% CI, 1.3 to 15.6), or those who were admitted into a ward with a high density of patients infected with CR A. baumannii (RR, 1.7; 95% CI, 1.2 to 2.5) to be at a significantly greater risk for the development of clinical colonization or infection with CR A. baumannii strains. In accordance, a combined infection control strategy was designed and implemented, including the sequential closure of all ICUs for decontamination, strict compliance with cross-transmission prevention protocols, and a program that restricted the use of carbapenem. Subsequently, a sharp reduction in the incidence rates of infection or colonization with A. baumannii, whether resistant or susceptible to carbapenems, was shown, although an alarming dominance of the carbapenem-resistant clones was shown at the end of the study.

Acinetobacter↗
PubMed2000

Characterization of a nosocomial outbreak caused by a multiresistant Acinetobacter baumannii strain with a carbapenem-hydrolyzing enzyme: high-level carbapenem resistance in A. baumannii is not due solely to the presence of beta-lactamases.

From February to November 1997, 29 inpatients at Ramón y Cajal Hospital, Madrid, Spain, were determined to be either colonized or infected with imipenem- and meropenem-resistant Acinetobacter baumannii (IMRAB) strains (MICs, 128 to 256 microg/ml). A wide antibiotic multiresistance profile was observed with IMRAB strains. For typing IMRAB isolates, pulsed-field gel electrophoresis was used. For comparative purposes, 30 imipenem- and meropenem-susceptible A. baumannii (IMSAB) strains isolated before, during, and after the outbreak were included in this study. The molecular-typing results showed that the outbreak was caused by a single IMRAB strain (genotype A). By cloning experiments we identified a class D beta-lactamase (OXA-24) encoded in the chromosomal DNA of this IMRAB strain which showed carbapenem hydrolysis. Moreover, the outer membrane profile of the IMRAB strain showed a reduction in the expression of two porins at 22 and 33 kDa when compared with genetically related IMSAB isolates. In addition no efflux mechanisms were identified in the IMRAB strains. In summary, we report here the molecular characterization of a nosocomial outbreak caused by one multiresistant A. baumannii epidemic strain that harbors a carbapenem-hydrolyzing enzyme. Although alterations in the penicillin-binding proteins cannot be ruled out, the reduction in the expression of two porins and the presence of this OXA-derived beta-lactamase are involved in the carbapenem resistance of the epidemic nosocomial IMRAB strain.

Acinetobacter↗
PubMed1998

[Bacteremia due to vancomycin-resistant enterococci in neutropenic cancer patients].

BACKGROUND: The aim of this study was to determine the incidence, clinical characteristics and outcome of vancomycin-resistant enterococcal bacteremia. PATIENTS AND METHODS: We included all cases of enterococcal bacteremia in neutropenic cancer patients documented between January 1986 and December 1995 in a 1,000-bed university hospital, where a prospective surveillance of all cases of bacteremia is regularly done. Molecular typing was performed on all vancomycin-resistant strains with the analysis of chromosomic DNA by macrorestriction. RESULTS: Seventeen cases of enterococcal bacteremia were documented. Seven (41%) were caused by vancomycin-resistant strains (E. faecium 3 and E. gallinarum 4), six of which occurred in the last 5 years of the study period. The average age of patients was 43 years (18-69) and most of them had acute leukemia. Eighty percent of these patients had received vancomycin and/or cephalosporins within 2 weeks prior to bacteremia. Previous administration of antibiotics was more frequent in patients with bacteremia caused by vancomycin-resistant enterococci than in those with bacteremia caused by susceptible strains (86% vs 30%; p < 0.05). The mean number of previous antibiotics (2.4 vs 0.8; p < 0.05) as well as days of treatment (13.6 vs 4.3; p = 0.05) were also higher among patients with resistant enterococcal bacteremia. The overall mortality was 57%. CONCLUSIONS: This study shows the emergence of sporadic cases of bacteremia caused by vancomycin-resistant enterococci in neutropenic cancer patients in our area. This fact seems to be related with the previous administration of antibiotics and advice that a rational use of these agents is needed.

Adolescent↗
PubMed1998

Outer membrane profiles of clonally related Klebsiella pneumoniae isolates from clinical samples and activities of cephalosporins and carbapenems.

Fifteen isolates of Klebsiella pneumoniae producing extended-spectrum beta-lactamases (ESBLs) isolated during a nosocomial outbreak were studied. The strains belonged to the same clonal type, as shown by pulsed-field gel electrophoretic analysis of chromosomal DNA. All the isolates were resistant to extended-spectrum cephalosporins, aztreonam, gentamicin, and fluoroquinolones and were susceptible to carbapenems, tobramycin, netilmicin, and amikacin. None of the isolates expressed the OmpK36 porin. Eight isolates, for which the MICs of cefoxitin were > or = 64 micrograms/ml, showed a diminished level or no expression of a 35-kDa porin. The MICs of meropenem, cefotaxime, and cefpirome were three to eight times higher for porin-deficient isolates than for isolates expressing the 35-kDa porin, but the MICs of imipenem increased two times for porin-deficient isolates compared to those for isolates expressing the porin. This MIC increase reverted to a level similar to that for the parental strain when porin-deficient isolates were transformed with the gene coding for the K. pneumoniae porin OmpK36. It is concluded that the high level of resistance to cefoxitin and the increase in the MICs of meropenem, cefotaxime, and cefpirome for the ESBL-producing K. pneumoniae isolates studied are associated with porin deficiency.

Bacterial Typing Techniques↗
PubMed1997

Radical chemoradiotherapy for elderly patients with bladder carcinoma invading muscle.

BACKGROUND: Chemoradiotherapy is becoming an alternative to radical cystectomy among patients with bladder carcinoma invading muscle. In 1988, the authors began a protocol with methotrexate, vinblastine, doxorubicin, and cisplatin (M-VAC regimen) and radiotherapy for these patients. Traditionally, age has been considered a determinant factor thereby excluding the older patients from the oncologic protocols that are considered to be more aggressive. The authors analyzed 20 patients (age > 70 years) who were treated during this period with the same protocol as the authors' other patients. METHODS: The study included 20 patients (age range, 70-78 years; median age, 74 years) including 4 patients with T2 disease, 9 with T3 disease, and 7 with T4 disease. All patients had a Karnofsky performance status of > 60. Treatment protocol included cytoreductive transurethral resection, 2 cycles of M-VAC chemotherapy, and radiotherapy (45 grays [Gy] on pelvic volume) with concurrent cisplatin (20 mg/m2 on Days 1-5. Response was determined by cystoscopic evaluation. If there was a complete response, radiotherapy continued until a total dose of 65 Gy; if there was not a complete response, cystectomy was performed. RESULTS: Tumor response after a dose of 45 Gy included 11 complete responses (55%), 5 partial responses (25%), and 4 nonresponses (20%). Overall survival was 75%, 34%, and 27% in the 2nd, 3rd, and 5th years of follow-up, respectively. Cause specific survival was 79%, 54%, and 38%, respectively. Survival for patients with complete response was 100%, 60%, and 48%, respectively. Severe toxicity was uncommon, with the most frequent toxicities being leukopenia and cystitis. No treatment-related death occurred with either treatment protocol. CONCLUSIONS: The age of the individual must not become a strict exclusion criterion for the radical treatment of old patients with invasive bladder carcinoma.

Aged↗
PubMed1997

Staphylococcus aureus nasal carriage as a marker for subsequent staphylococcal infections in intensive care unit patients.

From January to December 1994, 752 consecutive patients admitted to intensive care units (ICU) for more than two days were studied prospectively for Staphylococcus aureus colonization and infection. Nasal swabs were obtained at admission and weekly during the ICU stay. At ICU admission 166 patients (22.1%) were Staphylococcus aureus nasal carriers, while 586 were free of nasal colonization. Of the 166 nasal carriers, 163 harbored methicillin-sensitive Staphylococcus aureus (MSSA) and three methicillin-resistant Staphylococcus aureus (MRSA). During the ICU stay 24 of the 586 noncolonized patients became nasal carriers (11 MSSA and 13 MRSA), and one nasal carrier initially colonized by MSSA was reconlonized by MRSA. Staphylococcal infections were documented in 51 (6.8%) of the total 752 patients. After 14 days of ICU stay, the probability of developing staphylococcal infections was significantly higher for those patients who were nasal carriers at ICU admission than for those found to be initially negative (relative risk 59.6, 95% CI 20.37-184.32; p < 0.0001). In patients with ICU-acquired nasal colonization, most infections were documented prior to or at the time of the detection of the nasal colonization; thus, in this group of patients nasal carriage showed a lower predictive value for subsequent Staphylococcus aureus infections that that described classically. Paired isolates of nasal colonizing and clinical strains were studied by pulsed-field gel electrophoresis (PFGE) and mecA polymorphism analysis in 30 patients; identity was demonstrated in all but two patients. The results suggest that, outside the setting of an outbreak of MRSA, the detection of Staphylococcus aureus nasal carriers on admission may be particularly useful in identifying those patients who are at high risk for developing staphylococcal infections during their ICU stay.

Biomarkers↗