Piperacillin/tazobactam plus tobramycin versus ceftazidime plus tobramycin for the treatment of patients with nosocomial lower respiratory tract infection. Piperacillin/tazobactam Nosocomial Pneumonia Study Group.
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An open-label, randomized, comparative, multi-centre study was conducted at 25 centres in the USA and Canada to compare the safety and efficacy of piperacillin/tazobactam plus tobramycin with ceftazidime plus tobramycin in patients with lower respiratory tract infections. Piperacillin/tazobactam (3 g/375 mg) every 4 h or ceftazidime (2 g) every 8 h were administered i.v. for a minimum of 5 days. Tobramycin (5 mg/kg/day) given in divided doses every 8 h was administered to all patients. Patients with Pseudomonas aeruginosa isolated from respiratory secretions at baseline were to continue tobramycin for the duration of the study. Tobramycin could be discontinued in other patients after the baseline culture results were known. A total of 300 patients was randomized, 155 into the piperacillin/tazobactam group and 145 into the ceftazidime group. Of these, 136 patients (78 in the piperacillin/tazobactam group and 58 in the ceftazidime group) were considered clinically evaluable. Both groups were comparable for age, sex, duration of treatment and other demographic features. The clinical success rate in evaluable patients was significantly greater (P = 0.006) in the piperacillin/tazobactam treatment group (58/78; 74%) than in the ceftazidime group (29/58; 50%). Eradication of the baseline pathogen was significantly greater (P = 0.003) in the piperacillin/tazobactam group (66%) than in the ceftazidime group (38%). The clinical and bacteriological responses of those patients with nosocomial pneumonia were similar to the overall results. Twelve (7.7%) piperacillin/tazobactam-treated patients and 24 (17%) ceftazidime-treated patients died during the study (P = 0.03). Seven of the 24 deaths in the ceftazidime treatment group but only one of the 12 deaths in the piperacillin/tazobactam treatment group were directly related to failure to control infection. The majority of adverse events were thought by the investigator to be attributable to the patients' underlying disease and not drug related. In this study, piperacillin/tazobactam plus tobramycin was shown to be more effective and as safe as ceftazidime plus tobramycin in the treatment of patients with nosocomial LRTI. (+info)
Clinical and economic evaluation of subsequent infection following intravenous ciprofloxacin or imipenem therapy in hospitalized patients with severe pneumonia.
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A recent multicentre clinical study evaluated the safety and efficacy of i.v. ciprofloxacin therapy compared with imipenem-cilastatin in hospitalized patients with severe pneumonia. Monotherapy with i.v. ciprofloxacin was at least equivalent to imipenem in terms of bacteriological eradication and clinical response. In a single-centre, retrospective, post-therapy evaluation of persistent and subsequent infection, the incidence of gram-negative infections and associated costs were compared. The main elements of the economic analysis included costs of additional antimicrobial therapy and hospitalization. Thirty-two patients were randomized into the study, of whom 27 were efficacy-valid. The 13 patients randomized into the ciprofloxacin group were not significantly different from the 14 patients in the imipenem group in terms of clinical parameters. Clinical cure occurred in ten of 13 patients (77%) in the ciprofloxacin group and in seven of 14 (50%) in the imipenem group. Bacteriological eradication was achieved in 11 of 13 (85%) ciprofloxacin-treated and eight of 14 (57%) imipenem-treated patients. Five of 13 (38%) patients in the ciprofloxacin group and nine of 14 (64%) in the imipenem group experienced persistent or subsequent infection requiring post-treatment antimicrobials. In these five ciprofloxacin patients, three had cultures with gram-positive organisms only and two had cultures with both gram-positive and gram-negative organisms. In the nine imipenem-treated patients requiring post-study antimicrobials, all had gram-negative bacteria and three also had gram-positive organisms. The incidence of subsequent gram-negative infection in the two groups (15% vs 64%) was significantly different (P < 0.05). Pseudomonas aeruginosa was isolated from seven patients in the imipenem group but only one in the ciprofloxacin group (P < 0.05). Subsequent costs for post-therapy antimicrobials and hospital stay while receiving study and post-study drug therapy were evaluated; the cost per patient cure was US$29,000 for ciprofloxacin and US$76,000 for imipenem. Initial treatment of severe pneumonia with ciprofloxacin resulted in significantly less subsequent gram-negative infection and was associated with substantially lower curative costs. (+info)
Some immunological properties of lipopolysaccharide from Acinetobacter baumannii.
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Acinetobacter baumannii, mainly biotype 9, is an important nosocomial opportunist pathogen in Chile and other countries. The biological basis of its virulence and prevalence is still unknown. As lipopolysaccharide (LPS) is often associated with virulence, some biological properties of purified LPS from seven nosocomial isolates, comprising four isolates of A. baumannii biotype 9, two isolates of biotype 8 and one isolate of biotype 1, were investigated. LPS was extracted and purified from each isolate by the hot phenol-water method, and its ability to elicit a mitogenic response and to induce the synthesis of a tumour necrosis factor (TNF-alpha) in mouse spleen cells was determined. Activity was evaluated in vivo by determining the splenic index in comparison with LPS from Salmonella Typhimurium. All seven LPS samples were mitogenic on the basis of cellular proliferation experiments and six induced synthesis of TNF-alpha. Similar results were obtained in in-vivo experiments in which LPS induced spleen cell growth, as shown by determination of the splenic index. These results suggest that the LPS of A. baumannii might contribute to the pathogenic properties of this species. (+info)
The presence and sequence of endotracheal tube colonization in patients undergoing mechanical ventilation.
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Endotracheal tube colonization in patients undergoing mechanical ventilation was investigated. In the first part of this prospective study, the airway access tube was examined for the presence of secretions, airway obstruction and bacterial colonization, in cases undergoing extubation or tube change. In the second part of the study, the sequence of oropharyngeal, gastric, respiratory tract and endotracheal tube colonization was investigated by sequential swabbing at each site twice daily for 5 days in consecutive noninfected patients. In the first part, it was noted that all airway access tubes of cases undergoing extubation had secretions lining the interior of the distal third of the tube which were shown on scanning electron microscopy to be a biofilm. Gram-negative micro-organisms were isolated from these secretions in all but three cases. In the second part, it was noted that the sequence of colonization in patients undergoing mechanical ventilation was the oropharynx (36 h), the stomach (3660 h), the lower respiratory tract (60-84 h), and thereafter the endotracheal tube (60-96 h). Nosocomial pneumonia occurred in 13 patients and in eight cases identical organisms were noted in lower respiratory tract secretions and in secretions lining the interior of the endotracheal tube. The endotracheal tube of patients undergoing mechanical ventilation becomes colonized rapidly with micro-organisms commonly associated with nosocomial pneumonia, and which may represent a persistent source of organisms causing such infections. (+info)
Nosocomial vaccinia infection.
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Although hospital-associated spread of vaccinia has been reported in the past, there have been no recent reports. This paper describes hospital-associated spread of vaccinia virus infection, supplies data on the environmental survival of vaccinia virus and offers recommendations for the management of patients with vaccinia that may minimize the hazard of infection in other high-risk patients. (+info)
Density and molecular epidemiology of Aspergillus in air and relationship to outbreaks of Aspergillus infection.
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After five patients were diagnosed with nosocomial invasive aspergillosis caused by Aspergillus fumigatus and A. flavus, a 14-month surveillance program for pathogenic and nonpathogenic fungal conidia in the air within and outside the University Hospital in Rotterdam (The Netherlands) was begun. A. fumigatus isolates obtained from the Department of Hematology were studied for genetic relatedness by randomly amplified polymorphic DNA (RAPD) analysis. This was repeated with A. fumigatus isolates contaminating culture media in the microbiology laboratory. The density of the conidia of nonpathogenic fungi in the outside air showed a seasonal variation: higher densities were measured during the summer, while lower densities were determined during the fall and winter. Hardly any variation was found in the numbers of Aspergillus conidia. We found decreasing numbers of conidia when comparing air from outside the hospital to that inside the hospital and when comparing open areas within the hospital to the closed department of hematology. The increase in the number of patients with invasive aspergillosis could not be explained by an increase in the number of Aspergillus conidia in the outside air. The short-term presence of A. flavus can only be explained by the presence of a point source, which was probably patient related. Genotyping A. fumigatus isolates from the department of hematology showed that clonally related isolates were persistently present for more than 1 year. Clinical isolates of A. fumigatus obtained during the outbreak period were different from these persistent clones. A. fumigatus isolates contaminating culture media were all genotypically identical, indicating a causative point source. Knowledge of the epidemiology of Aspergillus species is necessary for the development of strategies to prevent invasive aspergillosis. RAPD fingerprinting of Aspergillus isolates can help to determine the cause of an outbreak of invasive aspergillosis. (+info)
Detection of clinically relevant genotypes of vancomycin-resistant enterococci in nosocomial surveillance specimens by PCR.
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This study evaluated a PCR method for the rapid detection of clinically significant genotypes of vancomycin-resistant enterococci (VRE) in nosocomial surveillance specimens. Detection of the vanA and vanB genes by multiplex PCR using 657 specimens that showed presumptive growth of VRE on bile esculin azide agar containing 6 mg of vancomycin/liter was compared to the conventional method. The diagnostic values for the PCR compared to the phenotypic method were as follows: 99.8% specificity, 95.4% sensitivity, 98.8% positive predictive value, and 99.3% negative predictive value. The average cost per test for PCR is $8.26, compared to $9.45 for the phenotypic method. The average turnaround time for detecting a VRE is 48 h for PCR, compared to 96 h for the conventional method. (+info)
Outbreak of extended spectrum beta lactamase producing Klebsiella pneumoniae in a neonatal unit.
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An outbreak of extended spectrum beta lactamase producing Klebsiella pneumoniae (ESBLKp) in a neonatal unit was controlled using simple measures. Normally, the control of such infections can be time consuming and expensive. Seven cases of septicaemia resulted in two deaths. ESBLKp isolates were subtyped by pulsed field gel electrophoresis, and four of the five isolates typed were identical. Control of the outbreak was achieved by altered empiric antibiotic treatment for late onset sepsis and prevention of cross infection by strict attention to hand washing. Widespread colonisation of babies in the unit was presumed, so initial surveillance cultures were not performed. No further episodes of sepsis occurred. (+info)