Pulmonary penetration of piperacillin and tazobactam in critically ill patients.

Pulmonary infections in critically ill patients are common and are associated with high morbidity and mortality. Piperacillin-tazobactam is a frequently used therapy in critically ill patients with pulmonary infection. Antibiotic concentrations in the lung reflect target-site antibiotic concentrations in patients with pneumonia. The aim of this study was to assess the plasma and intrapulmonary pharmacokinetics (PK) of piperacillin-tazobactam in critically ill patients administered standard piperacillin-tazobactam regimens. A population PK model was developed to describe plasma and intrapulmonary piperacillin and tazobactam concentrations. The probability of piperacillin exposures reaching pharmacodynamic end points and the impact of pulmonary permeability on piperacillin and tazobactam pulmonary penetration was explored. The median piperacillin and tazobactam pulmonary penetration ratios were 49.3 and 121.2%, respectively. Pulmonary piperacillin and tazobactam concentrations were unpredictable and negatively correlated with pulmonary permeability. Current piperacillin-tazobactam regimens may be insufficient to treat pneumonia caused by piperacillin-tazobactam-susceptible organisms in some critically ill patients.

Cerebral vasculitis and Cardiobacterium valvarum endocarditis.

We present a case of aortic and tricuspid native valve endocarditis in which Cardiobacterium valvarum was isolated from the blood culture of a 65-year-old man. Cardiobacterium valvarum is a fastidious, Gram-negative bacillus. The genus Cardiobacterium encompasses two species - Cardiobacterium valvarum and Cardiobacterium hominis. Although both species rarely feature as the aetiological agent of endocarditis, Cardiobacterium hominis has a higher incidence than Cardiobacterium valvarum. For this causative organism, we believe this is the first report of fatality prior to surgical intervention and the first clinical course to be complicated by cerebral vasculitis. Native valve endocarditis caused by Gram-negative bacilli is extremely rare and identification of isolates may require the use of reference laboratories with molecular identification techniques.

Isolation of Aspergillus species from the airway of lung transplant recipients is associated with excess mortality.

BACKGROUND: Aspergillus spp. are the leading cause of invasive fungal infection in lung transplant recipients. We investigated the relationship between the isolation of Aspergillus spp. from the respiratory tract of lung transplant recipients and their risk of mortality. METHODS: A retrospective, observational cohort study of all patients who received lung allografts between January 1999 and May 2011 at a single UK centre was performed. The time from transplantation to death was analysed using Cox regression models. Isolation of Aspergillus spp. from the respiratory tract was included as a covariate in the Cox regression model. RESULTS: Two hundred-thirteen patients were included. The median follow-up time was 5 years during which 102 patients (47.9%) died. Aspergillus was isolated from 74 (34.7%) patients. Twenty patients (27%) had Aspergillus isolated in the first 60 days post-transplant. Forty-one patients (55.4%) in the Aspergillus group and 61 patients (43.9%) in the non-Aspergillus group died during follow-up. A hazard ratio of 2.2 (95% CI 1.5-3.3; P < 0.001) for death following a positive Aspergillus sample was observed. CONCLUSION: Isolation of Aspergillus spp. from patients following lung transplantation is associated with a significant increase in mortality. Novel preventative strategies are required to minimise the impact of Aspergillus in lung transplant recipients.

A quantitative descriptive study of the prevalence of carriage (colonisation) of haemolytic streptococci groups A, B, C and G in pregnancy.

Invasive group B streptococcus (GBS) disease is a leading cause of neonatal death. There is no UK national screening programme for GBS in pregnancy, hence colonisation rates are unknown. Intrapartum antibiotic prophylaxis is given during labour to colonised women to reduce neonatal GBS transmission and subsequent invasive infection. Data about prevalence of other haemolytic streptococci in pregnancy, including group A streptococcus (GAS), are uncommon despite increasing importance. This study investigated colonisation in 100 pregnant women using conventional culture methods; 19% had GBS. This suggests that GBS carriage is common in the UK. The role of other ß-haemolytic streptococci remains undefined.

Patient segregation and aggressive antibiotic eradication therapy can control methicillin-resistant Staphylococcus aureus at large cystic fibrosis centres.

BACKGROUND: The prevalence of MRSA in patients with CF has risen in recent years. We adhere to a policy of segregation and barrier nursing to manage patients with MRSA, and we actively pursue eradication of MRSA. We have evaluated our experiences of MRSA infection in our large adult CF centre. METHOD: A retrospective review of all MRSA-positive patients from 1998 to 2008 was undertaken. Isolates were subjected to molecular identification to elucidate possible patient-to-patient transmission events. Eradication attempts were scrutinised. RESULTS: We have maintained a low incidence and prevalence (below 3%) of MRSA within this large cohort. A total of 15 pulsotypes of MRSA were identified among the 24 isolates examined, epidemiological data suggested no patient-patient transmission. Based on 6 month follow-up data, successful eradication was achieved in 81% patients. This includes those who had harboured infection for some time. Twenty-one (80.8%) required only one course of treatment, 3 (11.6%) patients required two different regimes and 2 (7.5%) required three courses to fully eradicate the organism. CONCLUSION: Strict infection control procedures can control MRSA infection and keep the prevalence low in CF clinics. Eradication is achievable in the majority of patients even when significant time has lapsed from initial isolation. In some instances, up to 3 courses of antibiotics were required to achieve eradication.

Audit of laboratory mycology services for the management of patients with fungal infections in the northwest of England.

BACKGROUND: Fungal infection is increasingly recognised as an important cause of morbidity and mortality, especially in immunocompromised patients. Little information exists on laboratory services available and the methods used by general microbiology laboratories to diagnose these important infections. AIM: To investigate the services microbiology laboratories in northwest England provide towards the diagnosis and management of superficial and deep fungal infections. METHODS: A questionnaire was sent to laboratories to get a holistic view of the support given to clinicians looking after patients with fungal infections. The aim was not to investigate details of each laboratory's standard operating procedures. The completed questionnaires, which formed the basis of this report, were returned by all 21 laboratories which were recruited. This study was conducted between March 2004 and September 2004. RESULTS: Services were provided to District General Hospitals and to six tertiary centres, including eight teaching hospitals by 16 laboratories. Their bed capacity was 250-1300 beds. Total specimens (including bacterial and viral) processed annually were 42 000-500,000 whereas fungal ones were 560-5400. CONCLUSION: In most microbiology laboratories of northwest England, clinicians were aware of the potential of fungal pathogens to cause infections especially in immunocompromised patients. Additional measures such as prolonged incubation of samples were introduced to improve fungal yield from patients at high risk. It is necessary to train and educate laboratory and medical staff about the role of serology and molecular methods in diagnosis and management of patients with fungal infection.

Identification of airborne dissemination of epidemic multiresistant strains of Pseudomonas aeruginosa at a CF centre during a cross infection outbreak.

BACKGROUND: Chronic Pseudomonas aeruginosa infection is a major cause of morbidity and mortality for individuals with cystic fibrosis (CF). P aeruginosa cross infection outbreaks have recently been reported at CF holiday camps and specialist centres. The mechanism of cross infection is unknown. A study was performed to look for the presence of epidemic strains of P aeruginosa in the environment of a CF centre during a cross infection outbreak and to examine their potential modes of spread between patients. METHODS: Microbiological sampling of the environment of the CF facility was performed, including room air sampling. Individual P aeruginosa strains were identified by bacterial fingerprinting. The typing patterns were compared with those of epidemic strains responsible for cross infection among the patients. RESULTS: Epidemic P aeruginosa strains were isolated from room air when patients performed spirometric tests, nebulisation, and airway clearance, but were not present in other areas of the inanimate environment of the CF centre. CONCLUSIONS: Aerosol dissemination may be the most important factor in patient-to-patient spread of epidemic strains of P aeruginosa during recent cross infection outbreaks at adult CF centres.

Spread of a multiresistant strain of Pseudomonas aeruginosa in an adult cystic fibrosis clinic.

We initiated a prospective surveillance study to investigate possible Pseudomonas aeruginosa cross-infection in our cystic fibrosis centre. We characterised isolates by pyocin typing and pulsed-field gel electrophoresis. 22 (14%) of 154 patients with chronic P aeruginosa had isolates with similar and new pyocin and pulsed-field gel electrophoresis types. The shared isolates showed unusual phenotypic features: they were non-pigmented, non-motile, and resistant to a number of antipseudomonal antibiotics. Cross-infection by a multiresistant P aeruginosa strain has therefore occurred in patients attending our cystic fibrosis centre. We recommend microbiological surveillance in other cystic fibrosis centres.

Burkholderia gladioli: recurrent abscesses in a patient with cystic fibrosis.

We describe a case of an adult patient with cystic fibrosis who developed chronic pulmonary infection and multiple episodes of soft tissue abscesses with Burkholderia gladioli; this organism should be added to the list of potential pathogens for individuals with cystic fibrosis.

Acute purulent exacerbation of chronic obstructive pulmonary disease and Chlamydia pneumoniae infection.

In order to investigate the role of bacteria, including Mycoplasma pneumoniae and especially Chlamydia pneumoniae in acute purulent exacerbations of chronic obstructive pulmonary disease (COPD), we examined sputum specimens and acute and convalescent sera taken 26 d apart from 49 outpatients experiencing an acute purulent exacerbation of COPD. The sera were tested for antibodies to C. pneumoniae with the microimmunofluorescence test, and for antibodies to M. pneumoniae with the indirect fluorescence antibody test. Routine microbiologic culture of sputum yielded potentially pathogenic microorganisms in 12 of the 49 patients (24%). Three patients (6%) showed serologic evidence of recent M. pneumoniae infection. Seven patients showed high IgG titers of >/= 1:1,024 to C. pneumoniae, and an additional four had a fourfold increase in IgG titer, suggesting reinfection with C. pneumoniae. Sputum from two of these 11 patients also grew Streptococcus pneumoniae, and one grew Moraxella catarrhalis. Patients with and without serologic evidence of current C. pneumoniae infection showed no significant differences in clinical features or pulmonary function. The high incidence of infection with C. pneumoniae (the sole causal agent in 16% of cases, and the causal agent with other agents in 6%) provides insight into the importance of this organism among agents leading to exacerbations of COPD in Turkey.

Electron microscopy and serological features of a patient with Q fever prosthetic valve endocarditis.

The clinical, serological and electron microscopic findings in a 47 year old woman with bioprosthetic valve coxiella endocarditis occurring 15 years after streptococcal endocarditis are described. The patient underwent valvular surgery a total of four times to control symptoms and remains well on medical therapy more than two years after her last operation.

Atraumatic suppurative mediastinitis and purulent pericarditis due to Eikenella corrodens.

Atraumatic suppurative mediastinitis is an uncommon infection. A case with an associated purulent pericarditis caused by Eikenella corrodens is reported.