Pilot study of ampicillin-ceftriaxone combination for treatment of orthopedic infections due to Enterococcus faecalis.

Serious Enterococcus faecalis infections usually require combination therapy to achieve a bactericidal effect. In orthopedic infections, the prognosis of enterococcal etiology is considered poor, and the use of aminoglycosides is questioned. The ampicillin-ceftriaxone combination has recently been accepted as alternative therapy for enterococcal endocarditis. After one of our patients with endocarditis and vertebral osteomyelitis was cured with ampicillin-ceftriaxone, we started a pilot study of orthopedic infections. Patients with infections due to E. faecalis (with two or more surgical samples or blood cultures) diagnosed during 2005 to 2008 were recruited. Polymicrobial infections with ampicillin- and ceftriaxone-resistant microorganisms were excluded. Patients received ampicillin (8 to 16 g/day)-ceftriaxone (2 to 4 g/day) and were followed up prospectively. Of 31 patients with E. faecalis infections, 10 received ampicillin-ceftriaxone. Including the first patient, 11 patients were treated with ampicillin-ceftriaxone: 3 with prosthetic joint infections, 3 with instrumented spine arthrodesis device infections, 2 with osteosynthesis device infections, 1 with foot osteomyelitis, and 2 with vertebral osteomyelitis and endocarditis. Six infections (55%) were polymicrobial. All cases except the vertebral osteomyelitis ones required surgery, with retention of foreign material in six cases. Ampicillin-ceftriaxone was given for 25 days (interquartile range, 15 to 34 days), followed by amoxicillin (amoxicilline) being given to seven patients (64%). One patient with endocarditis died within 2 weeks (hemorrhagic stroke) and was not evaluable. For one patient with prosthesis retention, the infection persisted; 9/10 patients (90%) were cured, but 1 patient was superinfected. Follow-up was for 21 months (interquartile range, 14 to 36 months). Ampicillin-ceftriaxone may be a reasonable synergistic combination to treat orthopedic infections due to E. faecalis. Our experience, though limited, shows good outcomes and tolerability and may provide a basis for further well-designed comparative studies.

The role of intraoperative cultures at the time of reimplantation in the management of infected total joint arthroplasty.

We reported our experience with the usefulness and interpretation of the significance of cultures at the second-stage exchange of infected arthroplasty in a prospective, 3-year follow-up study. When such intraoperative cultures were negative, patients received no therapy; when at least two cultures showed the same microorganism, results were interpreted as infection and patients were treated with antibiotics for 6-8 weeks with no more surgical procedures. Genotypic analysis (pulsed-field gel electrophoresis) was performed to analyse coagulase-negative Staphylococcus (CoNS) infections. Among 25 patients, 18 had negative cultures at the second-stage (group 1) and seven had positive cultures (group 2) receiving glycopeptides. Follow-up medians were 30 months for group 1 and 35 months for group 2; no patients in either group had persistence or recurrence of infection. All patients from group 2 had infection by CoNS at the second-stage; in six cases CoNS were also responsible for the initial infection. Genetic studies confirm that second-stage strains show different clonal identity than first-stage ones suggesting a superinfection rather than a real persistence of initial infection. Our results support the role of intraoperative cultures at the second-stage to identify patients at risk of recurrent infection who could benefit from early antibiotic therapy. The persistence of initial infections and the presence of new superinfections should be better defined according to genotypic studies.

Outbreak of Legionnaires' disease in immunosuppressed patients at a cancer centre: usefulness of universal urine antigen testing and early levofloxacin therapy.

This report describes an outbreak of Legionnaires' disease in severely immunosuppressed patients hospitalised at a cancer centre. Universal urine antigen testing and early levofloxacin therapy appeared to lower case fatality rates in comparison with previous reports concerning this high-risk population. This diagnostic and therapeutic strategy should be considered when facing a nosocomial outbreak of Legionnaires' disease in immunosuppressed hosts.

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.

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.

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.

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.

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.

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.

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.