Bone and joint infections of the hand

BACKGROUND

Little guidance is currently available for standardized diagnostic protocols and therapeutic recommendations for bone and joint infections (BJIs) of the hand.

OBJECTIVES

To summarize the available data in the scientific English-language literature on the diagnosis and treatment of native BJIs of the hand. To illustrate these concepts from a narrative point of view in areas where there is lack of evidence.

SOURCES

We performed a systematic PubMed and Internet search of studies that investigated hand BJIs in adult patients.

CONTENT

Few studies have systematically investigated and validated diagnostic concepts, classifications or surgical treatment protocols. Most concepts derive from traditional intra-institutional experience, expert opinions and extrapolations from infections in large joints and long bones. Similarly, there is no uniformly accepted infection definition of BJIs of the hand. The best-documented literature is available for microbiological findings and antibiotic treatment duration in uncomplicated native joint arthritis of the fingers. Retrospective studies and one prospective randomized trial suggest that post-surgical targeted antibiotic therapy of 2 weeks results in a microbiological cure rate of ≥88%.

IMPLICATIONS

Studies on diagnostic workup and infection definition and classification are urgently needed to compare inter-institutional outcome results and generate guidelines for the best patient care. For uncomplicated pyogenic arthritis of native joints, current evidence suggests that a 2-week course of antibiotic therapy following surgery cures the infection.

Non-compliance with IDSA guidelines for patients presenting with methicillin-susceptible Staphylococcus aureus prosthetic joint infection is a risk factor for treatment failure

OBJECTIVE

The long-term impact of treatment strategies proposed by the IDSA guidelines for patients presenting with methicillin-susceptible S. aureus (MSSA) prosthetic joint infection (PJI) is not well-known.

PATIENTS AND METHODS

Retrospective (2000-2010) cohort study including patients presenting with MSSA hip or knee PJI. A univariate Cox analysis was performed to determine if the non-compliance with IDSA surgical guidelines was a risk factor for treatment failure.

RESULTS

Eighty-nine patients with a mean follow-up of 2.8 years were included. Non-compliance with IDSA surgical guidelines was associated with treatment failure (hazard ratio 2.157; 95% CI [1.022-4.7]). The American Society of Anesthesiologists score, inadequate antimicrobial therapy, and a rifampicin-based regimen did not significantly influence patient outcome.

CONCLUSION

Based on the IDSA guidelines, if a patient presenting with MSSA PJI is not eligible for implant retention, complete implant removal is needed to limit treatment failure.

Cefepime plasma concentrations and clinical toxicity: a retrospective cohort study

OBJECTIVES

Cefepime remains an important antibiotic for severe bacterial infections, yet some meta-analyses have shown elevated mortality among patients randomized to it. Therapeutic drug monitoring (TDM) of β-lactam antibiotics is increasing, but optimal plasma concentrations remain unknown. We examined clinical outcomes of patients undergoing cefepime TDM in an initial effort to define the drug's toxicity threshold.

METHODS

In this single-centre retrospective cohort study, we enrolled all adult hospitalized patients receiving cefepime and undergoing TDM from January 2013 through July 2016. The primary outcome was the incidence of clinical toxicity; a secondary outcome was clinical failure. Plasma samples were analysed via high-performance liquid chromatography with ultraviolet detection.

RESULTS

A total of 161 cefepime concentrations were drawn from 93 patients. Roughly half (82/161, 51%) and one-third (49/161, 30%) were trough and steady-state levels from patients receiving intermittent and continuous infusions, respectively; median concentrations were 17.6 mg/L (IQR 9.7-35.2) and 29.2 mg/L (IQR 18.9-45.9). Ten patients (11%) experienced a neurologic event considered at least possibly related to cefepime; neurotoxicity was associated with poorer renal function (median creatinine clearance 54 (IQR 39-97) vs. 75 mL/min/1.73² (IQR 44-104)) and longer cefepime durations (mean 8.3 (SD±6.7) vs. 13.3 days (± 14.2), p = 0.071). Patients with trough levels >20 mg/L had a fivefold higher risk for neurologic events (OR 5.05, 95% CI 1.3-19.8).

CONCLUSIONS

Neurotoxicity potentially related to cefepime occurred at plasma concentrations >35 mg/L. For those receiving intermittent infusions, trough concentrations >20 mg/L should be avoided until further information is available from prospective studies.

[Management of an infection associated with a prosthetic arthroplasty: the necessity of collaboration between surgeon and infectiologist]

The total number of total knee and hip joint arthroplasties is constinuously rising, due to an increasing population of physically active elderly patients. For primary elective arthroplasties, the infection risk ranges between I and 2%, but equals to a high morbidity, costs and complications for the individual infected patient. Diagnosis and management of prosthetic joint infections are improving. We review the latest consensus on the diagnosis and management of these infections and reveal some insight in still debated issues.

Challenges in diagnosing infection in the diabetic foot

Diagnosing the presence of infection in the foot of a patient with diabetes can sometimes be a difficult task. Because open wounds are always colonized with microorganisms, most agree that infection should be diagnosed by the presence of systemic or local signs of inflammation. Determining whether or not infection is present in bone can be especially difficult. Diagnosis begins with a history and physical examination in which both classic and 'secondary' findings suggesting invasion of microorganisms or a host response are sought. Serological tests may be helpful, especially measurement of the erythrocyte sedimentation rate in osteomyelitis, but all (including bone biomarkers and procalcitonin) are relatively non-specific. Cultures of properly obtained soft tissue and bone specimens can diagnose and define the causative pathogens in diabetic foot infections. Newer molecular microbial techniques, which may not only identify more organisms but also virulence factors and antibiotic resistance, look very promising. Imaging tests generally begin with plain X-rays; when these are inconclusive or when more detail of bone or soft tissue abnormalities is required, more advanced studies are needed. Among these, magnetic resonance imaging is generally superior to standard radionuclide studies, but newer hybrid imaging techniques (single-photon emission computed tomography/computed tomography, positron emission tomography/computed tomography and positron emission tomography/magnetic resonance imaging) look to be useful techniques, and new radiopharmaceuticals are on the horizon. In some cases, ultrasonography, photographic and thermographic methods may also be diagnostically useful. Improved methods developed and tested over the past decade have clearly increased our accuracy in diagnosing diabetic foot infections.

[Community-acquired bacterial septic arthritis in adults: diagnosis and treatment]

The diagnosis of acute native joint bacterial infection can be difficult, because of its non- specific clinical and biological manifestation. Its management is often an emergency. Following a joint puncture, early joint lavage is performed, either by surgical drainage or by repeated arthrocentesis; and accompanied by systemic antibiotics, of which the ideal duration and route of administration remains unknown. The postoperative care is characterized by joint mobilization to avoid joint stiffening.

Non-tuberculous mycobacterial infections of the hand

Non-tuberculous mycobacterial infections of the hand are difficult to treat and require a long time before remission. But how long should we wait to see an improvement? To answer this question, the published scientific literature was reviewed in English, French and German. Tuberculosis, arthritis and osteomyelitis cases were excluded. A total of 241 non-tuberculous mycobacterial hand infections in 38 scientific publications were retrieved. Most were case reports or series. The median age of the patients was 58years and one third was female. Patients were immunocompromised in 17 episodes. The most common species were Mycobacterium marinum in 198 episodes (82%), followed by M. chelonae in 13 cases (5%). There were no cases of mixed infection. Most infections were aquatic in origin and community-acquired, and were treated with a combination of surgical debridement and long-duration systemic combination antibiotic therapy (14 different regimens; no local antibiotics) for a median duration of 6months. The median number of surgical procedures was 2.5 (range 1-5). Clinical success was not immediate: a median period of 3months (range 2-6) was necessary before the first signs of improvement were observed. The majority (173 cases; 76%) remained entirely cured after a median follow-up time of 1.7years (range, 1-6). Only two microbiological recurrences occurred (1%). However, 49 patients (21%) had long-term sequelae such as pain, stiffness and swelling. The approach of long-duration antibiotic treatment in combination with repeated surgery for mycobacterial soft tissue infections of the hand leads to few recurrences. However, clinical success is not immediate and may take up to 3months.

TYPE OF STUDY

Therapeutic study: systematic review of level III studies.

LEVEL OF EVIDENCE

III.

[Deep soft tissue infections]

The clinical presentations of deep soft tissue infections can, initially, mimicry superficial skin infections such as erysipelas. However, a rapidly deteriorating health status, the spreading of the lesions and the lack of clear visual limitation of the infection on the skin are hallmarks of a more severe underlying infection, which may endanger patients' life. An immediate adequate multidisciplinary approach to therapy within a few hours is mandatory. The first step is surgical exploration with debridement of all infected tissues, accompanied by antibiotic therapy and additional supportive measures. Despite progress in the understanding of the physiopathology, the delay between suspicion of diagnosis and surgical exploration remains critical. Because of the low incidence of such severe infections, only multicenter studies might reveal deeper insights of optimal therapeutic strategies in the future and for possible improved patients' survival.

Diabetic foot infections: state-of-the-art

Foot infections are frequent and potentially devastating complications of diabetes. Unchecked, infection can progress contiguously to involve the deeper soft tissues and ultimately the bone. Foot ulcers in people with diabetes are most often the consequence of one or more of the following: peripheral sensory neuropathy, motor neuropathy and gait disorders, peripheral arterial insufficiency or immunological impairments. Infection develops in over half of foot ulcers and is the factor that most often leads to lower extremity amputation. These amputations are associated with substantial morbidity, reduced quality of life and major financial costs. Most infections can be successfully treated with optimal wound care, antibiotic therapy and surgical procedures. Employing evidence-based guidelines, multidisciplinary teams and institution-specific clinical pathways provides the best approach to guide clinicians through this multifaceted problem. All clinicians regularly seeing people with diabetes should have an understanding of how to prevent, diagnose and treat foot infections, which requires familiarity with the pathophysiology of the problem and the literature supporting currently recommended care.

Is there any benefit in pre-operative urinary analysis before elective total joint replacement?

Whether patients with asymptomatic bacteriuria should be investigated and treated before elective hip and knee replacement is controversial, although it is a widespread practice. We conducted a prospective observational cohort study with urine analyses before surgery and three days post-operatively. Patients with symptomatic urinary infections or an indwelling catheter were excluded. Post-discharge surveillance included questionnaires to patients and general practitioners at three months. Among 510 patients (309 women and 201 men), with a median age of 69 years (16 to 97) undergoing lower limb joint replacements (290 hips and 220 knees), 182 (36%) had pre-operative asymptomatic bacteriuria, mostly due to Escherichia coli, and 181 (35%) had white cells in the urine. Most patients (95%) received a single intravenous peri-operative dose (1.5 g) of cefuroxime as prophylaxis. On the third post-operative day urinary analysis identified white cells in 99 samples (19%) and bacteriuria in 208 (41%). Pathogens in the cultures on the third post-operative day were different from those in the pre-operative samples in 260 patients (51%). Only 25 patients (5%) developed a symptomatic urinary infection during their stay or in a subsequent three-month follow-up period, and two thirds of organisms identified were unrelated to those found during the admission. All symptomatic infections were successfully treated with oral antibiotics with no perceived effect on the joint replacement.

We conclude that testing and treating asymptomatic urinary tract colonisation before joint replacement is unnecessary.

Cite this article: Bone Joint J 2014;96-B:390–4.

Managing diabetic foot infections: a review of the new guidelines

Foot infections are amongst the most frequent and severe complications linked to diabetes mellitus and are the most common non-traumatic cause of lower limb amputation. Appropriate management of these infections, however, can improve their outcome. The Infectious Diseases Society of America (IDSA) constituted a panel of multidisciplinary experts in 2004 to develop guidelines for the diagnosis and treatment of diabetic foot infections, which have been widely used and validated. Because there have been many new publications in the field, and the IDSA updated the format for all guidelines, they asked the diabetic foot infection committee to revise the 2004 publication. The revised guidelines, based on a thorough and systematic review of the literature, were published in 2012. They are built around 10 key questions concerning diagnosis and treatment; these are answered, with a summary of the evidence provided, and given a GRADE rating for the strength of the recommendation and quality of the evidence. The updated guidelines also include advice on implementing these recommendations, suggestions for regulatory changes to enhance care for diabetic foot infections, recommendations on performance measures and suggested areas for future research. They also include 14 tables, 1 figure, and 345 references, most of which were published after the first guidelines in 2004. Implementing these guidelines should improve outcomes in patients with a DFI.

Short duration of antibiotic prophylaxis in open fractures does not enhance risk of subsequent infection

We undertook a retrospective case-control study to assess the clinical variables associated with infections in open fractures. A total of 1492 open fractures were retrieved; these were Gustilo and Anderson grade I in 663 (44.4%), grade II in 370 (24.8%), grade III in 310 (20.8%) and unclassifiable in 149 (10.0%). The median duration of prophylaxis was three days (interquartile range (IQR) 1 to 3), and the median number of surgical interventions was two (1 to 9). We identified 54 infections (3.6%) occurring at a median of ten days (IQR 5 to 20) after trauma. Pathogens intrinsically resistant to the empirical antibiotic regimen used (enterococci, Enterobacter spp, Pseudomonas spp) were documented in 35 of 49 cases (71%). In multivariable regression analyses, grade III fractures and vascular injury or compartment syndrome were significantly associated with infection. Overall, compared with one day of antibiotic treatment, two to three days (odds ratio (OR) 0.6 (95% confidence interval (CI) 0.2 to 2.0)), four to five days (OR 1.2 (95% CI 0.3 to 4.9)), or > five days (OR 1.4 (95% CI 0.4 to 4.4)) did not show any significant differences in the infection risk. These results were similar when multivariable analysis was performed for grade III fractures only (OR 0.3 (95% CI 0.1 to 3.4); OR 0.6 (95% CI 0.2 to 2.1); and OR 1.7 (95% CI 0.5 to 6.2), respectively).

Infection in open fractures is related to the extent of tissue damage but not to the duration of prophylactic antibiotic therapy. Even for grade III fractures, a one-day course of prophylactic antibiotics might be as effective as prolonged prophylaxis.

Cite this article: Bone Joint J 2013;95-B:831–7.

[Where are we in the treatment of chronic osteomyelitis?]

Chronic osteomyelitis is a multifaceted bacterial infection with common features, which requires surgery for remission. The duration and modality of concomitant administration of antibiotic agents for adult patients is still based on expert opinions. The traditional recommendation of 6 to 12 weeks of antibiotic therapy with intravenous administration for at least the first 2 weeks is more and more challenged in favor of an oral antibiotic treatment with selected agents from the start. There is no evidence that the total duration of antibiotic therapy for more than 6-12 weeks improves outcome, when compared with shorter regimens. External advice from an expert team with combined surgeons and infectious disease physicians may help to reduce antibiotic consumption in a cost-effective way.

[Measures against surgical site infections in orthopaedic surgery]

Orthopaedic surgery has low healthcare-associated infection incidences compared to other surgical disciplines. However, whenever they occur, these infections are associated with substantial morbidity, prolonged hospital stay, high costs, and difficulties of eradication with life-long recurrence risks. Among the many measures to prevent orthopaedic surgical site infections, only few are based on strong evidence, and there is insufficient evidence to ascertain which element is superior to any other. This highlights the need for multimodal approaches involving active post-discharge surveillance, as well as measures at every step of the care process; from the individual patient to department-wide interventions targeting all infections, and including antibiotic stewardship.

[Open fractures of the tibia in the adult: surgical treatment and complications]

Open tibial shaft fractures represent high-energy trauma and are associated with a substantial risk of complications. Management is an emergency, and the first steps in treatment include antibiotic prophylaxis, tetanus booster, surgical debridement, irrigation of the wound and stabilization of the fracture. The Gustilo and Anderson classification helps to guide definitive treatment. Intramedullary nailing is the surgical technique of choice. An indirect approach utilizing external fixation is recommended for Gustilo IIIB and IIIC fractures. The most prevalent complications are compartment syndrome (10%), infection (2%-40% without antibiotics according to Gustilo grading, most notably in the presence of vascular lesions), aseptic nonunion (23%), venous thromboembolism (60% without prevention) and anterior knee pain (>50%).

No need to search for the source of haematogenous arthroplasty infections

QUESTIONS UNDER STUDY/PRINCIPLES

Prosthetic joint infections (PJI) may be a potential sentinel event for an unknown neoplastic or infectious source in elderly patients. However, the value and cost-effectiveness of investigations to determine the origin of these infections is unknown.

METHODS

Retrospective study at Geneva University Hospitals, evaluating associated medical examinations performed in search of the origin of all presumed surgical site and haematogenous arthroplasty infections.

RESULTS

A total of 182 PJI were found in 182 patients (median age 75 years). Seventy PJI (38%) were classified as probably haematogenous, occurring more than 2 years post-implantation, with 27 (15%) due to Gram-negative pathogens. Overall, the origin of PJI was found solely by admission history in 28 cases (15%). Among the remaining 154 cases, no remote origin could be detected despite 17 echocardiograms, 17 other sonograms, 49 chest x-rays, 23 computed tomograms, 107 urinary cultures, 11 endoscopies, 9 scintigraphies and 31 medical specialist consultations. The average cost of these exams was 675 Swiss francs (845 US$) per PJI. At long-term follow-up six patients were found to have developed a neoplasm, of which only one (hepatocellular carcinoma after PJI due to Streptococcus bovis) could eventually be attributed to prior infection.

CONCLUSIONS

From an epidemiologic point of view, patient history is the best way to predict the origin of PJI. Blind additional radiographic or endoscopic exams are costly, inconclusive and do not contribute to the management of these cases.

[Diabetic foot infection: a multidisciplinary approach]

Diabetic foot infection is a frequent, multifactorial and multifacettal disease. Its management requires an interdisciplinary collaboration. Multiple medical and surgical specialties are enrolled for its prevention and treatment, for good reasons. Concomitant management by various specialists shows a significant reduction in amputation rates. We review the issues of this interdisciplinary collaboration.

False serologic evidence for acute primary toxoplasmosis during liver transplantation for fulminant hepatitis B: a case report

Acute primary Toxoplasma gondii infection is usually considered to be a contraindication for solid organ transplantation. Recent reports of acute T. gondii infection have highlighted the need to include T. gondii serology in the pretransplant screening of solid-organ transplant recipients. However such serology might be misleading. We describe the case of a 25-year-old woman who received a liver transplantation for life-threatening liver failure due to hepatitis B virus infection. The presence of high IgM titers against T. gondii, as detected by membrane immunoassay, immunofluorescence, and mu-capture ELISA tests, together with the absence of IgG antibodies in the immediate pretransplant serology screening suggested acute primary T. gondii infection at the time of transplantation. We initiated a preemptive therapy with intravenous clindamycin and cotrimoxazole. However, negative PCR and IgA capture assays, together with the absence of a sustained IgG response finally excluded the initial diagnosis of primary toxoplasmosis, leading to discontinuation of antitoxoplasmosis therapy. This case illustrates the problem that, in the context of fulminant hepatitis B, serologic markers for acute primary toxoplasmosis can be falsely positive. Confirmation by PCR and IgA antibody determinations is required to confirm this diagnosis.

[Antibiotic prophylaxis before dental procedures in arthroplasty patients]

Antibiotic prophylaxis is commonly prescribed to patients with total arthroplasties before a dental intervention. This attitude is not evidence-based for several reasons: 1) the usual pathogens of prosthetic joint infections are not of oral origin; 2) even if given, systemic antibiotic do not completely suppress the occult bacteraemia occurring during dental intervention and 3) humans may have up to twelve episodes of occult bacteraemia of dental origin per day. Routine antibiotic prophylaxis should be clearly distinguished from the antibiotic treatment required in case of established oral cavity infection. A constant optimal oral and dental hygiene is more important in terms of prevention and should be routinely recommended to every patient carrying a joint arthroplasty.

[New methods for the diagnosis of implant-associated infections]

For successful treatment of prosthetic joint infection, the identification of the infecting microorganism is crucial. Cultures of synovial fluid and intraoperative periprosthetic tissue represent the standard method for diagnosing prosthetic joint infection. Rapid and accurate diagnostic tools which can detect a broad range of causing microorganisms and their antimicrobial resistance are increasingly needed. With newer diagnostic techniques, such as sonication of removed implants, microcalorimetry, molecular methods and mass spectrometry, the sensitivity has been significantly increased. In this article, we describe the conventional and newer diagnostic techniques with their advantages and potential future applications.

Antibiotic prophylaxis before invasive dental procedures in patients with arthroplasties of the hip and knee

More than a million hip replacements are carried out each year worldwide, and the number of other artificial joints inserted is also rising, so that infections associated with arthroplasties have become more common. However, there is a paucity of literature on infections due to haematogenous seeding following dental procedures. We reviewed the published literature to establish the current knowledge on this problem and to determine the evidence for routine antibiotic prophylaxis prior to a dental procedure.

We found that antimicrobial prophylaxis before dental interventions in patients with artificial joints lacks evidence-based information and thus cannot be universally recommended.

‘My five moments for hand hygiene’: a user-centred design approach to understand, train, monitor and report hand hygiene

Hand hygiene is a core element of patient safety for the prevention of healthcare-associated infections and the spread of antimicrobial resistance. Its promotion represents a challenge that requires a multi-modal strategy using a clear, robust and simple conceptual framework. The World Health Organization First Global Patient Safety Challenge 'Clean Care is Safer Care' has expanded educational and promotional tools developed initially for the Swiss national hand hygiene campaign for worldwide use. Development methodology involved a user-centred design approach incorporating strategies of human factors engineering, cognitive behaviour science and elements of social marketing, followed by an iterative prototype test phase within the target population. This research resulted in a concept called 'My five moments for hand hygiene'. It describes the fundamental reference points for healthcare workers (HCWs) in a time-space framework and designates the moments when hand hygiene is required to effectively interrupt microbial transmission during the care sequence. The concept applies to a wide range of patient care activities and healthcare settings. It proposes a unified vision for trainers, observers and HCWs that should facilitate education, minimize inter-individual variation and resource use, and increase adherence. 'My five moments for hand hygiene' bridges the gap between scientific evidence and daily health practice and provides a solid basis to understand, teach, monitor and report hand hygiene practices.

Absidia posttraumatic infection: successful treatment with posaconazole

The class zygomycetes is a large group of filamentous fungi found ubiquitously in nature, primarily in humid soil. Their virulence in immunocompetent hosts is low; therefore, they are usually considered to be contaminants of cultures. In the present study, we describe a patient who had severe traumatic injury with an Absidia infection, who developed intolerance to antifungal treatment with amphotericin B, but responded to posaconazole treatment.

Die Folgen einer ungenügenden Herdimmunität bei «pädiatrischen» Infektionskrankheiten – Beispiel einer Masernepidemie

Von Januar bis Mitte Februar 2005 wurden dem Kantonsarzt von Genf 15 Fälle von bestätigten Masern gemeldet; verglichen zu einem einzelnen Fall im 2004. Ungewöhnlich an dieser Epidemie war das Alter der betroffenen Personen von 17 bis 44 Jahren. Vier unter ihnen waren Mitarbeiter eines öffentlichen Spitals, die sich nach Kontakt zu einem einzigen, 44-jährigen Patienten ansteckten und die Infektion zum Teil weiter übertrugen. Die Annahme, dass Masern eine pädiatrische Infektion sind, erschwerte die Diagnose. Keiner der betroffenen Erwachsenen war immun nach dem heutigen Stand der Empfehlungen. Trotz vorhandenem Impfplan, behördlichen Empfehlungen, Kostenübernahme durch die Krankenkassen und den guten Impfergebnissen mit den heute zur Verfügung stehenden Vakzinen, ist die freiwillige Durchimpfungsrate in der Schweiz unter Kindern und Erwachsenen zu gering um den Ausbruch von Epidemien zu verhindern. Im Gegensatz zu den Zielen des Bundesamt für Gesundheit (BAG) und der Weltgesundheitsorganisation (WHO) sind wir in der Schweiz aus verschiedenen Gründen noch nicht so weit eine genügend hohe Herdimmunität aufzubauen, um gesundheitliche und volkswirtschaftliche Schäden durch aufflackernde Epidemien zu verhindern.

Impact of positive legionella urinary antigen test on patient management and improvement of antibiotic use

AIM

To assess the incidence of legionella infection over a 27 month period at a large university hospital.

MATERIAL AND METHODS

The present retrospective cohort study enrolled patients with legionellosis, defined as those presenting a positive urinary antigen for legionella together with a medical history, clinical findings, and radiological findings consistent with pneumonia. These patients were evaluated to determine the relation between their test results and changes in treatment modalities. A control group of patients with pneumonia but a negative urinary antigen test for legionella were also analysed.

RESULTS

Twenty seven of 792 assessed patients tested positive for legionella. In 22 of these patients, legionella active antibiotics were administered empirically. In seven patients, the test results prompted a legionella specific treatment, whereas in 12 cases, non-specific antibiotics were stopped within 24 hours. Overall, treatment was altered in more than half of the patients as a result of the test results.

CONCLUSIONS

The urinary antigen may have a direct impact on clinical management of pulmonary legionellosis. However, patient comorbidities and individual clinical judgment are still important for determining the best treatment to be given in each individual case.

Secular trends of nocardia infection over 15 years in a tertiary care hospital

AIMS

To assess the incidence of nocardia infection over 15 years in a tertiary care hospital.

METHODS

Over a 15 year period, Nocardia spp were isolated from 20 patients hospitalised at the Geneva University Hospitals, Switzerland.

RESULTS

Sixteen patients had one or more underlying conditions. The median time between symptom onset and diagnosis was 30 days. The most common initial unconfirmed diagnosis was pulmonary tuberculosis (four). The lung was involved in 16 cases, followed by the central nervous system (two) and skin (two); one patient had disseminated infection. The most common species identified was N asteroides. In vitro susceptibility testing was performed on 14 of 20 strains. All strains were susceptible to imipenem and amikacin. Initial treatment with trimethoprim/sulfamethoxazole (TMP/SMX) was started in 14 patients, although five patients had to be switched to another treatment because of side effects or lack of efficacy. A cure was observed in 15 patients, death in three, and relapse or complications in two.

CONCLUSIONS

Nocardiosis can become a severe infection and mainly affects profoundly immunocompromised patients. Differential diagnosis often delays the time to diagnosis, which worsens the outcome. New diagnostic tools, such as the polymerase chain reaction, could provide more rapid and reliable results. TMT/SMX was the most commonly prescribed treatment, but needed to be changed for another treatment because of side effects or lack of efficacy in a considerable proportion of patients. Imipenem should be used as an alternative treatment for severely ill patients, and the sulfa combination for less severe infections.

Simultaneous assessment of muscle and skin blood fluxes with the laser-Doppler technique

The laser-Doppler technique was used to assess local muscle and skin blood fluxes at the lower limb in 20 healthy volunteers. After puncturing the anterior tibial muscle with a steel cannula, a single-fibre probe with a diameter of 0.5 mm was inserted into the muscle. Simultaneously, the skin blood flux was measured at calf and foot. The muscle blood flux at rest was 3.5 to 4 times higher than the skin blood flux at calf or foot. The spatial variability of the muscle blood flux at three different sites of measurement was considerable and tended to be higher than in the skin of the calf. After an arterial occlusion lasting 3 min, peak flux was reached in the muscle after 18.7 +/- 9.8 s, in the skin of the calf after 16.8 +/- 9.3 s, and in the skin of the foot after 22.9 +/- 14.6 s (NS). The relative flux increase during reactive hyperaemia was significantly lower in the muscle (2.7 +/- 1.3) than in the skin of the calf (3.9 +/- 1.9; p<0.05) or the foot (5.1 +/- 3.5; p<0.005). The reproducibility of reactive hyperaemia response in muscle was excellent with unchanged probe position, but exhibited a marked variability on different days. The laser-Doppler technique provides the possibility for simultaneous measurement of flow dynamics in muscle and skin with a high temporal resolution. Methodological problems include differences in probe geometry of the single-fibre compared to standard probes and differences in optical properties of the tissues. Direct comparison of flux values may, therefore, be subject to criticism, but not the comparative analysis of relative flux changes. The influence of tissue trauma on muscle blood flux has to be considered for the analysis of flux data.