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Biomedical subjects

R Verdaguer

Publications and source records attributed to R Verdaguer.

At least 19 recordsLinked to original sources

An insidious nosocomial outbreak due to Salmonella enteritidis.

OBJECTIVES: To investigate an increase in the number of Salmonella enteritidis isolates detected in a large hospital to ascertain whether it was due to a nosocomial source, to identify the mechanisms of transmission, and to institute effective control measures to prevent future episodes. DESIGN: Observational study, survey of all microbiological samples positive for S. enteritidis detected in the hospital, outbreak investigation, and review of the literature. SETTING: A tertiary-care teaching hospital for adults in Barcelona, Spain. RESULTS: During a 7-month period from May to November 1998, we identified 22 inpatients with S. enteritidis infection for whom nosocomial acquisition was strongly suspected. The attack rate was 0.138 per 1,000 patient-days. All affected patients were immunosuppressed and overall mortality was 41% (9 of 22). A sample of a meal cooked in the kitchen was culture positive for S. enteritidis. All isolates shared the same antibiotic susceptibility pattern and all except one shared the same pulsed-field gel electrophoresis (PFGE) pattern, but PFGE could not differentiate between outbreak-related and control strains. After compliance with kitchen hygiene procedures was emphasized and cleansing was intensified, no more cases were detected. CONCLUSIONS: Apparently, sporadic cases of S. enteritidis may be part of an outbreak with a low attack rate. A small but persistent inoculum affecting only individuals with special predisposition for Salmonella infection might account for this. Suspicion should be raised in hospitals and institutions with a highly susceptible population.

Adult↗

An outbreak of carbapenem-resistant Pseudomonas aeruginosa in a urology ward.

OBJECTIVE: To investigate an outbreak of carbapenem-resistant Pseudomonas aeruginosa (CRPA) in a urology ward. METHODS: Patients infected or colonized with CRPA were prospectively identified by daily laboratory surveillance. Routine infection-control measures were reinforced, disinfection protocols were revised, and a surveillance program was set up, analyzing cross-transmission in the nursing ward and environment cultures from urology wards and the operating theater. CRPA isolates from clinical and environment samples were studied by pulsed-field gel electrophoresis (PFGE), following XbaI and SpeI restriction. RESULTS: From February 1998 to September 2000, 59 adult urology patients were colonized or infected by CRPA. All patients had been operated on prior to identification of the CRPA isolate and 79% of these procedures were performed in the same cystoscopy room. No patients had received prior carbapenem therapy. No cross-transmission was detected, and environment cultures from the urology ward and theater were negative except for five samples collected in the cystoscopy room. PFGE identified a single clone in the isolates from different patients and the environment samples. CONCLUSIONS: The PFGE analysis indicated that the CRPA outbreak resulted from the contamination of the cystoscopy room via an unsealed drain. The outbreak ended when the drain was sealed.

Anti-Bacterial Agents↗

Effects of antibiotics on protected specimen brush sampling in ventilator-associated pneumonia.

The effects of antibiotic treatment on the results of protected specimen brushing (PSB) in ventilator-associated pneumonia were prospectively assessed by performing this procedure before antibiotic treatment, and 12, 24, 48 and 72 h after initiation of antibiotic treatment, in 35 ventilated patients who developed pneumonia during mechanical ventilation. The number of micro-organisms isolated, their concentration (colony-forming units (cfu) mL(-1)), and the number of cases with a positive PSB (> or =10(3) cfu x mL(-1)) were evaluated. Within 12 h of the initiation of effective antibiotic treatment a rapid, significant decrease in the numbers of organisms isolated, their individual concentrations and the percentage of positive PSB results were observed. Certain bacterial species (Streptococcus pneumoniae, Haemophilus influenzee) appeared to be more vulnerable to antibiotics than others (Staphylococcus aureus, Pseudomonas aeruginosa, Acinetobacter baumanni). This data confirms that prior antibiotic treatment, even after only a few hours of activity, significantly decreases the sensitivity of protected brush specimen; this effect appears to be particularly marked among the species involved in early ventilator associated pneumonia.

Adolescent↗

Prospective study of the usefulness of sputum Gram stain in the initial approach to community-acquired pneumonia requiring hospitalization.

From February 1995 through May 1997, we prospectively studied 533 patients with community-acquired pneumonia requiring hospitalization in order to assess the current usefulness of sputum Gram stain in guiding the etiologic diagnosis and initial antibiotic therapy when applied routinely. Sputum samples of good quality were obtained in 210 (39%) patients, 175 of whom showed a predominant morphotype. Sensitivity and specificity of Gram stain for the diagnosis of pneumococcal pneumonia were 57% and 97%, respectively; the corresponding values for Haemophilus influenzae pneumonia were 82% and 99%. Patients with a predominant morphotype were more frequently treated with monotherapy than were patients without a demonstrative sputum sample (89% vs. 75%; P<.001). Analysis of our data shows that a good-quality sputum sample can be obtained from a substantial number of patients with community-acquired pneumonia. Gram stain was highly specific for the diagnosis of pneumococcal and H. influenzae pneumonia and may be useful in guiding pathogen-oriented antimicrobial therapy.

Adolescent↗

Streptococcal meningitis in adult patients: current epidemiology and clinical spectrum.

Streptococci other than Streptococcus pneumoniae are a rare cause of bacterial meningitis in adults. We report 29 cases of streptococcal meningitis (1977-1997). The patients comprised 19 men and 10 women, with a mean age +/- standard deviation of 47 +/- 18 years. Nine cases were secondary to neurosurgical procedures, seven to brain abscess, five to cerebrospinal fluid pericranial fistula, and three to endocarditis. Causative microorganisms included the following: viridans group streptococci, 20 cases; anaerobic streptococci, 3; Streptococcus agalactiae, 3; Streptococcus bovis, 2; and Streptococcus pyogenes, 1. Four Streptococcus mitis strains showed decreased susceptibility to penicillin (MIC, 0.5-2 microg/mL). Five patients (17%) died. The infection is increasing in the hospital setting. Streptococci resistant to penicillin should be considered in the empirical treatment of nosocomial meningitis. In cases of community-acquired infection, anaerobic streptococci or streptococci of the Streptococcus milleri group should alert the clinician to the presence of an undiagnosed brain abscess, whereas oral streptococci of the viridans group suggest the diagnosis of bacterial endocarditis.

Adolescent↗

Usefulness of PCR and antigen latex agglutination test with samples obtained by transthoracic needle aspiration for diagnosis of pneumococcal pneumonia.

In a large number of cases, the etiology of community-acquired pneumonia (CAP) is not established. Some cases are probably caused by Streptococcus pneumoniae. Transthoracic needle aspiration (TNA) culture has a limited sensitivity which might be improved by antigen detection or gene amplification techniques. We evaluated the capacity of a PCR assay and a latex agglutination test to detect S. pneumoniae in samples obtained by TNA from 95 patients with moderate-to-severe CAP. Latex agglutination and PCR had sensitivities of 52.2 and 91.3%, specificities of 88.7 and 83.3%, positive predictive values of 62.3 and 65.6%, and negative predictive values of 83.3 and 96.5%, respectively, when culture techniques were used as the "gold standard." When we considered expanded criteria for the diagnosis of pneumococcal pneumonia as a standard for our calculations, latex agglutination and PCR had sensitivities of 53.6 and 89.7%, specificities of 93.0 and 90.0%, positive predictive values of 78.9 and 81.3%, and negative predictive values of 80.3 and 94.7%, respectively. The additional diagnosis provided by the PCR assay compared to latex agglutination was 12.2% (95% confidence interval of the difference from 0.4 to 20. 1%). PCR was more sensitive than TNA culture, particularly in patients who had received prior antibiotic therapy (83.3 versus 33. 3%). Although PCR is a very sensitive and specific technique, it has not proved to be cost-effective in clinical practice. Conversely, latex agglutination is a fast and simple method whose results might have significant implications for initial antibiotic therapy.

Antibodies, Bacterial↗

Clinical and epidemiological findings in mechanically-ventilated patients with methicillin-resistant Staphylococcus aureus pneumonia.

Over the 5-year period from 1990 to 1994, a prospective cohort study was conducted to define the clinical and epidemiological characteristics of ventilator-associated methicillin-resistant Staphylococcus aureus (MRSA) pneumonia acquired during a large-scale outbreak of MRSA infection. Of 2411 mechanically ventilated patients, 347 (14.4%) acquired MRSA, 220 (63.4%) had MRSA positive respiratory tract samples and 41 (18.6%) developed ventilator-associated MRSA pneumonia. The overall attack rate for ventilator-associated MRSA pneumonia was 1.56 episodes/1000 ventilator days, but annual attack rates varied according to the trend of the outbreak (range 4.9-0.2). In comparison with methicillin-sensitive Staphylococcus aureus (MSSA), which was implicated in 98 episodes of ventilator-associated pneumonia, MRSA caused exclusively late-onset ventilator-associated pneumonia, while MSSA caused both early-onset [55 of 98 (56.1%) episodes] and late-onset [43 of 98 (43.8%) episodes] ventilator-associated pneumonia. Logistic regression analysis of all patients with Staphylococcus aureus pneumonia revealed intubation for more than 3 days (odds ratio (OR),1.11; confidence interval (CI):1.03-1.18) and prior bronchoscopy (OR,5.8; CI,1.85-18.19) to be independent variables associated with MRSA pneumonia. The results indicate that MRSA ventilator-associated pneumonia is a frequent complication in intensive care patients, manifesting itself as late-onset pneumonia in patients who have been intubated for prolonged periods and/or have often undergoing previous bronchoscopy.

Adult↗

Protected bronchoalveolar lavage in the diagnosis of ventilator-associated pneumonia.

The aim of this study was to evaluate the diagnostic efficacy of protected bronchoalveolar lavage (PBAL) in ventilator-associated pneumonia (VAP), and to determine the effect of antibiotic therapy on its microbiological and cytological results. We prospectively studied 102 episodes of suspected VAP in 93 patients. Subsequent follow-up confirmed VAP in 35 of the 102 (34%) cases. In 55 of the 102 (55%) VAP was ruled out, and the diagnosis remained undetermined in 12 of the 102 (12%) episodes. In the VAP group, 30 of the 35 (86%) PBAL (> or = 10(4) colony-forming units (cfu)-mL-1) cultures were positive. In the non-VAP group, 5 of the 55 (9%) PBAL cultures were positive. A Giemsa stain of PBAL samples was performed in 32 of the 35 cases of VAP. Intracellular organisms (ICO) were found in 24 of the 32 (75%) cases. Seven of the other eight cases without evidence of ICO were already on antibiotics. In the non-VAP group, ICO were present in only 1 out of 55 (2%) cases. The mean ICO was significantly higher in the group who had not received antibiotics when compared with those patients previously treated for less than 48 h (p < or = 0.01) and those treated for more than 48 h (p = 0.009). The sensitivity of protected bronchoalveolar lavage quantitative cultures was 87% and the specificity 91%. The sensitivity of cytological analysis for intracellular organisms was 75% and the specificity 98%. According to our results, if the patient is already on antibiotics, the direct examination of protected bronchoalveolar lavage fluid is less reliable, although still helpful.

Anti-Bacterial Agents↗

A single daily dose of ceftriaxone for bacterial meningitis in adults: experience with 84 patients and review of the literature.

Although the pharmacokinetics of ceftriaxone allows its administration in a single daily dose, this practice is not standard in the treatment of bacterial meningitis. Herein, we review our experience and that of other investigators with this mode of therapy. We used a single daily dose of ceftriaxone (50 mg/[kg.d]; maximum, 4 g/d) for the treatment of bacterial meningitis in 84 adult patients. Meningitis was due to Neisseria meningitidis in 34 cases, to Streptococcus pneumoniae in 25, to Escherichia coli in three, to Klebsiella pneumoniae in two, to Haemophilus influenzae in two, to viridans streptococci in two, and to an unknown agent in 16. Eleven patients died, for an overall mortality of 13%; therapy failed in three additional cases. The mean trough levels of ceftriaxone in cerebrospinal fluid was 3.5 micrograms/mL; the median trough bactericidal titer at this site was 1:128. Both our experience and that in the literature suggest that a single daily dose is optimal when ceftriaxone is used for the treatment of bacterial meningitis.

Adolescent↗

Efficacy, safety, and therapeutic relevance of transthoracic aspiration with ultrathin needle in nonventilated nosocomial pneumonia.

In order to determine the potential indications of transthoracic needle aspiration (TNA) using the ultrathin 25G needle for the diagnosis of nonopportunistic lung infections, we prospectively analyzed the diagnostic efficacy, safety, and therapeutic implications of its results in 97 patients with nonventilated nosocomial pneumonias (NVNP). The sensitivity of TNA was 60.9%. Specificity and positive predictive value (PPV) were 100%. Negative predictive value (NPV) was 34.1%. The complications in the studied cases were nil in 89 cases (91.8%), transient hemoptoic expectoration (< 10 ml) in five (5.2%), and self-limited partial pneumothorax in three (3.1%). No complications needing treatment were observed. On the basis of a positive TNA result, the initial antibiotic treatment was modified in 29 of 97 (29.9%) cases. In twelve of these, the empirical antibiotic regimen was demonstrated to be ineffective. We conclude that, using the 25G needle, TNA has a good diagnostic efficacy and is a safe procedure for the etiologic investigation of NVNP. A positive TNA result has significant therapeutic relevance, even in cases where broad-spectrum antibiotics are empirically prescribed.

Adolescent↗

Risk factors for the development of Haemophilus influenzae pneumonia in hospitalized adults.

Potential risk factors for developing Haemophilus influenzae nosocomial pneumonia have not been sufficiently studied. We wanted to investigate the incidence and risk factors for the development of Haemophilus influenzae pneumonia in the hospital by means of a multivariate analysis. A total of 468 cases of nosocomial pneumonia were observed during the study period, 317 (68%) of which were aetiologically diagnosed by means of highly reliable methods, and H. influenzae was isolated in 57 of them. Fifty of the 57 episodes of H. influenzae pneumonia occurred in mechanically-ventilated patients. Underlying diseases were: medical in 12 cases, surgical in 15 cases, and traumatological in 22. Variables associated with Haemophilus influenzae nosocomial pneumonia in intubated patients after the univariate analysis were: "period between admission and pneumonia 2-7 days" and "no previous antibiotics". A multivariate analysis demonstrated that the variables "no previous antibiotics" and "coma on admission" were risk factors for H. influenzae pneumonia. In nonintubated patients, no risk factors were found for H. influenzae pneumonia compared with other nosocomial pneumonia. We conclude that H. influenzae was involved in 57 out of 317 (18%) of nosocomial pneumonia registered in our institution, and the majority of patients (50 out of 57) were mechanically-ventilated. In this particular subgroup, coma of the patient on admission to hospital and absence of antibiotic treatment prior to developing pneumonia constitute two definite risk factors for developing H. influenzae nosocomial pneumonia.

Adult↗

[Mechanical ventilation-associated pneumonia and the prevention of stress ulcer. A randomized clinical trial of antacids and ranitidine versus sucralfate].

BACKGROUND: To study two groups of patients intubated with different prophylaxis of stress gastric ulcer in a prospective randomized trial. The differential effect on gastric pH, gastric colonization and the incidence of pneumonia associated to mechanical ventilation (PMV) were analyzed. METHODS: A prospective randomized study was carried out in two groups of patients: 1) prophylaxis with antacids and H2 blockers (AA+H2) and 2) prophylaxis with sucralfate. Intubated patients without initial respiratory infection were included in the protocol. Periodically gastric aspirations were collected measuring gastric pH and performing semi-quantitative cultures. When pneumonia was suspected bronchial brushing was carried out with telescoped catheter (BBTC) and quantitative culture. RESULTS: Fifty-one patients were studied (n = 51), distributed into 25 in the AA+H2 group and 26 in the sucralfate group. In the first group mean pH was higher (5.3 +/- 1.7) than in the sucralfate group (3.2 +/- 2.1) (p = 0.006). Nosocomial pneumonia (NP) was suspected on 25 occasions: 20 patients were positive for NP, 11 in the AA+H2 group and nine in the sucralfate group with no significant differences being observed. S. aureus, S. pneumoniae and H. influenzae (n = 14) were the etiology of predominant PMV. The global mortality of the group was of 22%. CONCLUSIONS: The prophylaxis of stress ulcers in intubated patients treated with antacids and ranitidine provoked higher gastric pH and an increase in gastric colonization in comparison to that observed with sucralfate. No significant differences were observed in the frequency of pneumonia by PMV diagnosed by BBTC.

Adult↗

Gram-negative bacillary cellulitis in patients with hepatic cirrhosis.

Eight episodes of gram-negative bacillary cellulitis in seven patients with hepatic cirrhosis are reported. The patients comprised five women and two men (mean age 59.6 years). The diagnosis was based on a positive culture of specimens obtained by needle aspiration from cutaneous lesions. All patients had grade C cirrhosis according to Pugh's classification. Cellulitis involved the lower extremities in all cases. Five patients developed bullous lesions, three ulcers, two abscesses and two extensive cutaneous necrosis. A single bacterial species was found in seven cases. Organisms isolated were Klebsiella pneumoniae (3 cases), Escherichia coli (2 cases), Pseudomonas aeruginosa (2 cases), Proteus mirabilis (1 case) and Aeromonas hydrophila (1 case). Bacteremia was documented in six cases. Four patients died, death being related to sepsis in three of them. It is concluded that gram-negative bacilli should be considered as possible pathogens in severe infectious cellulitis in patients with advanced cirrhosis. Microbiological study of cutaneous specimens obtained by needle aspiration may be of high diagnostic value in these cases.

Aged↗

Risk factors for nosocomial Legionella pneumophila pneumonia.

Over a 5-yr period, from January 1985 to January 1990, we prospectively studied 300 episodes of nosocomial pneumonia in a 1,000-bed teaching hospital. All cases had an accurate bacteriologic diagnosis obtained by means of highly reliable techniques. Legionella pneumophila caused a total of 36 episodes; 22 were endemic and 14 occurred during an epidemic outbreak. No patient with Legionella pneumonia had been intubated before infection. To identify risk factors for nosocomial L. pneumophila pneumonia, we compared the 22 endemic cases of nosocomial pneumonia due to L. pneumophila with the 264 cases due to other bacteria. After adjusting for other variables by means of logistic regression analysis, cytotoxic chemotherapy (OR = 5.2; 95% CI, 1.5 to 17.9) and use of corticosteroids (OR = 4.6; 95% CI, 1.5 to 14.1) were positively associated with L. pneumophila pneumonia, whereas previous antibiotic therapy (OR = 0.2; 95% CI, 0.1 to 0.8) and lowered consciousness (OR = 0.2; 95% CI, 0.07 to 0.8) were negatively associated. The major risk factors for Legionella pneumonia delineated in this study should be considered in the clinical approach to and empiric therapy of patients with suspected nosocomial pneumonia.

Adrenal Cortex Hormones↗

Comparison of two ascitic fluid culture methods in cirrhotic patients with spontaneous bacterial peritonitis.

The conventional method of ascitic fluid culture detects bacteria in only 50% of cirrhotic patients with neutrocytic ascites and suspected spontaneous bacterial peritonitis (SBP). We have prospectively compared two ascites culture methods in cirrhotic patients with spontaneous bacterial peritonitis: 1) conventional (on chocolate agar, blood agar, Mac Conkay agar, and thioglycolate broth), and 2) modified [inoculation of 10 ml of ascites in a tryptic soy broth (TSB) blood culture bottle at the patient's bedside]. In a 21-month period, 70 episodes of SBP were diagnosed according to our criteria in 60 cirrhotic patients. Both culture methods were performed simultaneously. The conventional grew bacteria in 40 episodes (57%), whereas the modified grew bacteria in 54 episodes (77%), a significantly higher sensitivity (p = 0.0001). In 16 cases (23%), ascitic culture was negative by both methods. The mortality rate was higher among patients with culture-positive SBP than those with culture-negative SBP (46% vs 37%), but did not reach statistical significance. We conclude that ascitic fluid inoculated into a TSB blood culture bottle at the patient's bedside should be used routinely for ascites culture in cirrhotic patients.

Ascitic Fluid↗