Should scintigraphy be completely excluded from the diagnosis of periprosthetic joint infection?

AIM: To analyse the diagnostic performance of bone and leukocyte scintigraphy for periprosthetic joint infection before excluding the test from routine practice, and to analyse the possible benefit of bone marrow scintigraphy in inconclusive cases. MATERIALS AND METHODS: From 2012 to 2018, all patients with a total hip or knee arthroplasty who had a bone and leukocyte scintigraphy performed and underwent revision surgery were included. Bone marrow scintigraphy was indicated only in cases in which bone and leukocyte scintigraphy were inconclusive. Diagnosis of periprosthetic joint infection was confirmed by positive intraoperative cultures after revision surgery. RESULTS: A total of 105 patients were included. Eighteen patients had total hip arthroplasties (18.1%) and 86 had total knee arthroplasties (81.9%). Mean age was 74 years. Nineteen cases were diagnosed with a periprosthetic joint infection. Bone and leukocyte scintigraphy had 64% sensitivity and 97% specificity. Bone marrow scintigraphy increased sensitivity and specificity to 88% and 100%, respectively. CONCLUSION: Bone and leukocyte scintigraphy possesses high sensitivity and specificity for the diagnosis of chronic periprosthetic joint infection. The additional use of bone marrow scintigraphy significantly increases diagnostic performance. For these reasons, bone scintigraphy is reserved for inconclusive cases of chronic periprosthetic joint infection.

Ceftolozane/tazobactam in the treatment of osteomyelitis and skin and soft-tissue infections due to extensively drug-resistant Pseudomonas aeruginosa: clinical and microbiological outcomes.

Infections due to multidrug-resistant bacteria (MDR) are currently a clinical challenge, mainly in elderly patients. The antimicrobial spectrum, safety and efficacy of ceftolozane/tazobactam (C/T) make it an attractive option for the treatment of MDR bacterial infections beyond the indications approved to date. Here we report our experience with C/T in four cases of osteomyelitis and three cases of skin and soft-tissue infections due to extensively-drug-resistant Pseudomonas aeruginosa.

Aetiology of community-acquired pneumonia among adults in an H1N1 pandemic year: the role of respiratory viruses.

This study aimed to determine the aetiology of community-acquired pneumonia (CAP) by adding polymerase chain reaction (PCR) to conventional methods and to describe the clinical and laboratory features between patients with bacterial pneumonia (BP) and viral pneumonia (VP). Adults with CAP admitted from November 2009 to October 2010 were included. Demographics, comorbidities, severity and clinical features were recorded. Conventional microbiological methods included blood and sputum cultures, acute and convalescent serologic samples, and antigen urinary detection. New methods included multiplex PCR for Mycoplasma pneumoniae, Legionella pneumophila, Chlamydophila pneumoniae, Bordetella pertussis and 15 respiratory viruses. A total of 169 patients were included. Using conventional methods, we identified a pathogen in 51 % of cases. With PCR, up to 70 % of cases had an aetiological diagnosis. Forty-five patients had BP (34 %), 22 had VP (17 %) and 25 (19 %) had co-infection (BP and VP). Pneumococci and respiratory syncytial virus (RSV) were the most frequently identified pathogens. Procalcitonin (PCT) and C-reactive protein (CRP) median values were significantly higher in BP than in VP patients. Shaking chills, higher CURB score and shock were significantly more frequent in BP. A viral infection was identified in more than one-third of patients with CAP. Clinical and laboratory features could help to differentiate between VP and BP and to guide empirical therapy.

Pseudomonas aeruginosa in patients hospitalised for COPD exacerbation: a prospective study.

Risk factors for Pseudomonas aeruginosa (PA) isolation in patients hospitalised for chronic obstructive pulmonary disease (COPD) exacerbation remain controversial. The aim of our study was to determine the incidence and risk factors for PA isolation in sputum at hospital admission in a prospective cohort of patients with acute exacerbation of COPD. We prospectively studied all patients with COPD exacerbation admitted to our hospital between June 2003 and September 2004. Suspected predictors of PA isolation were studied. Spirometry tests and 6-min walking tests were performed 1 month after the patients were discharged. High-resolution computed tomography (HRCT) was performed in a randomised manner in one out of every two patients to quantify the presence and extent of bronchiectasis. Patients were followed up during the following year for hospital re-admissions. A total of 188 patients were included, of whom 31 (16.5%) had PA in sputum at initial admission. The BODE (body mass index, airflow obstruction, dyspnoea, exercise capacity) index (OR 2.18, CI 95% 1.26-3.78; p = 0.005), admissions in the previous year (OR 1.65, CI 95% 1.13-2.43; p = 0.005), systemic steroid treatment (OR 14.7, CI 95% 2.28-94.8; p = 0.01), and previous isolation of PA (OR 23.1, CI 95% 5.7-94.3; p<0.001) were associated with PA isolation. No relationship was seen between bronchiectasis in HRCT and antibiotic use in the previous 3 months. PA in sputum at hospital admission is more frequent in patients with poorer scoring on the BODE index, previous hospital admissions, oral corticosteroids and prior isolation of PA.

Invasive pneumococcal disease among children in a health district of Barcelona: early impact of pneumococcal conjugate vaccine.

This study evaluated the impact of heptavalent pneumococcal conjugate vaccine (HPCV) on invasive pneumococcal disease (IPD) in children aged < or = 5 years in Barcelona, Spain. The incidence of IPD, vaccine uptake and prevalence of nasopharyngeal colonisation were analysed in two different periods: 1999-2001 (pre-licence period), and 2002-2004 (post-licence period). In total, 121 cases of IPD were identified. The overall incidence of IPD decreased from 96.9 cases/100,000 to 90.6 cases/100,000 (OR 0.93, 95% CI 0.69-1.26, p 0.71) between the two periods. The proportion of cases caused by non-vaccine-related serotypes (NVS) increased from 21% to 43.7% (OR 2.9, 95% CI 1.2-7, p 0.01). IPD was diagnosed in seven vaccinated children, six of whom were infected by NVS. There was a trend of diminishing prevalence of resistance to penicillin and macrolides in 2002-2004. The incidence of empyema increased from 1.7 to 8.5/100,000 (OR 4.5, 95% CI 0.91-18, p 0.06). The rate of vaccination ranged from 4.8% to 34%. It was concluded that the rates of IPD in this area did not decrease following the introduction of HPCV. The low uptake of vaccine and the greater proportion of colonisation/infection by NVS probably explain these findings. A trend of increasing empyema was also apparent. A decrease in the prevalence of penicillin and macrolide resistance paralleled the progressive uptake of vaccine.

Sheltering as a protective measure against airborne virus spread.

The dispersion of airborne viruses can play an important role in the spread of a disease. Especially for short or moderate emission periods - such as emissions from farms or accidental releases from laboratories or industrial plants - indoor concentrations can be significantly lower than outdoor concentrations. The relationships between these two concentrations are analysed for continuous, temporary and instantaneous releases. The efficiency of sheltering as a protective measure for persons or animals is discussed.

Infected total hip arthroplasty--the value of intraoperative histology.

Intraoperative histology showed a sensitivity of 100% and a specificity of 98%. These results were better than those observed for the other tests evaluated. Our data provide evidence that intraoperative histology is useful tool in the diagnosis of infected total hip arthroplasty.

Simulated airborne spread of Aujeszky's disease and foot-and-mouth disease.

The atmospheric dispersion of virus was simulated using a computer model which had been developed for predicting the dispersion of toxic gases from chemical engineering plants. The results were compared with data from four outbreaks in which virus was believed to have been transported by air: two outbreaks of foot-and-mouth disease in the United Kingdom in 1967 and outbreaks of Aujeszky's disease in Yorkshire in 1981 to 1982 and Indiana in 1988. There was relatively good agreement with most of these data. The paper shows that the model could be useful in an emergency because the risk of virus spread could be predicted in real time.

[Cotrimoxazole plus rifampicin in the treatment of staphylococcal osteoarticular infection]. / Cotrimoxazol más rifampicina en el tratamiento de la infección osteoarticular estafilocócica.

OBJECTIVE: To evaluate the efficacy and safety of cotrimoxazol plus rifampicin in staphylococcal osteoarticular infection. METHOD: Open, non-comparative study of adult hospitalized patients with documented staphylococcal bone infection. RESULTS: From Feb 1989 to Dec 1993 28 episodes of staphylococcal bone infection were treated in 14 men and 13 women; the mean age was 48 +/- 21 years (range, 11-84). They received cotrimoxazol (7 mg/kg/day of trimethoprim) plus rifampicin (600-1200 mg/day), both orally, every 8 to 12 h with a mean duration of treatment of 34.2 +/- 8.2 days (range, 21 to 55 days). This antibiotic regimen was initiated at the same time that appropriate surgery for each specific condition was undertaken. Diagnoses were postsurgical osteomyelitis (10 cases), infected total hip prostheses (4 cases, one with 2 episodes), osteomyelitis secondary to external pin fixation (5 cases), soft tissue infections linked to orthopedic implants (3 cases), two cases of metatarsal osteomyelitis (one diabetic foot and one patient with polineuropathy), and one case each of chronic osteomyelitis of femur, hematogenous lumbar spondylitis and posttraumatic osteomyelitis. Four patients had bacteremia. The duration of the infection, prior to surgery was less than one month in 12 episodes, 1 month to 2 years in 14, and in 2 cases, of 10 and 13 years, respectively. In 23 episodes the causal agent was Staphylococcus aureus and in 5 cases it was coagulase-negative staphylococci. Patients had received previous parenteral therapy with other antimicrobials during 2-40 days (X: 18.6 +/- 10.2 days). All patients but one had resolution of the infection and are currently asymptomatic 6 months to 5 years posttreatment in the 21 evaluable cases (X: 38 +/- 13.1 months). Five patients had adverse effects secondary to the antibiotic combination and in three these were severe enough to discontinue the antimicrobials. In no case of the 11 patients with post-treatment control cultures were staphylococci recovered from the wound. CONCLUSIONS: The combination of cotrimoxazole plus rifampicin, both given orally, was highly effective in this selected group of patients. This combination should be considered as a useful alternative therapy of staphylococcal bone infection and deserves further study.

[Fluoroquinolone and aminoglycoside resistance in chromosomal cephalosporinase-overproducing gram-negative bacilli strains with inducible beta-lactamase]. / Resistencia a fluorquinolonas y aminoglucósidos en cepas hiperproductoras de cefalosporinasa cromosómica de bacilos gramnegativos con betalactamasa inducible.

INTRODUCTION: The increasing prevalence of stable derepressed mutants over-producers of type I chromosomal cephalosporinase in inducible Enterobacteriaceae and Pseudomonas aeruginosa challenges the adequacy of third generation cephalosporins in the empirical treatment of certain nosocomial infections. We sought to determine the frequency of stable over-producers of type I enzyme and their associated resistance to fluoroquinolones and aminoglycosides. METHODS: Disc-diffusion and MIC determinations to extended-spectrum beta-lactams, imipenem, ciprofloxacin and gentamicin were performed in all cell isolates of inducible enteric bacteria (Enterobacter spp., Citrobacter spp., Serratia spp., Morganella morganii, Providencia spp.) and P. aeruginosa collected during the period of study (1992-1993). RESULTS: A total of 1,426 isolates of inducible enteric bacteria and P. aeruginosa were studied. Each one represented a single patient. Among the 511 isolates of enteric bacteria 15.1% of strains were found to be stable derepressed mutants (Serratia 2.2%; Morganella spp., 3%; Providencia and Proteus 3%; Citrobacter spp., 10%; Enterobacter spp., 23.6%); among the 916 P. aeruginosa isolates studied, 9.2% were stable over-producers. Among Citrobacter, Providencia and Proteus spp., 53.1% of stable over-producers were resistant to ciprofloxacin versus 20.2% of non-over-producers (p < 0.01); in P. aeruginosa, 35.3% of over-producers were resistant to gentamicin versus 25.0% in non-over-producers (p < 0.01). CONCLUSION: The prevalence of stable derepressed mutants is high among enteric bacteria and P. aeruginosa with type I inducible beta-lactamase. These strains frequently exhibit resistance to fluoroquinolones and aminoglycosides, reducing considerably the available therapeutic options.

[Hip prosthesis infection: diagnostic approach and treatment of 27 cases]. / Infección de prótesis de cadera: aproximación diagnóstica y tratamiento de 27 episodios.

BACKGROUND: Preoperative diagnosis of hip prosthesis infection (HPI) is difficult. There is no therapeutic option which is completely effective and without risk. The aim of this study was to evaluate a diagnostic approach and therapeutic strategy in a group of patients with HPI. PATIENTS AND METHODS: A retrospective study of 27 episodes of HPI diagnosed by anatomopathologic and/or microbiologic examination of surgical samples was performed. RESULTS: Twenty-three patients with 27 episodes of HPI out of a total of 24 hip prosthesis (HP) were treated. The infection was early in 15 episodes. The etiologic agents were plasmocoagulase negative staphylococcus (NSP) in 11 cases, P. aeruginosa in 8, S. aureus in 5, Enterococcus sp. in 2 and miscellaneous in the remaining cases. In 2 cases the infection was polymycrobial. Following a mean follow period of 22.6 +/- 15.2 months, 13 out of the 14 patients in whom the prosthesis was withdrawn were cured (in 4 a second prosthesis was implanted), one out of 6 in those in whom the prosthesis remained in situ following debridement, and 2 out of 3 episodes in whom reimplantation was performed over time. The withdrawal of the prosthesis was significantly greater than debridement in the treatment of early infection (p < 0.001). The total mean length of postoperative antibiotherapy was 48.2 +/- 17 days. No differences were observed in the oral versus parenteral treatment (p = 0.22), and nor was prognosis worse in those treated for less than 42 days. CONCLUSIONS: The authors' experience suggests that attempts to save a hip prosthesis in early infection usually fail. In addition to prosthesis withdrawal or implantation of another prosthesis, six weeks of postoperative antibiotic therapy, which may be oral route, appear to be sufficient.