Acute Haematogenous Revision Total Knee Arthroplasty Infection by Streptococcus canis Treated by Debridement, Antibiotics, and Implant Retention: A Case Report.

Prosthetic joint infections (PJIs) are one of the most feared complications by orthopaedic surgeons. Haematogenous PJI represents an important part of PJI cases. Streptococcus canis is an extremely rare cause of haematogenous PJI and its medical and surgical treatment and prognosis are not well established. We present a 79-year-old female patient who had a revision total knee arthroplasty (rTKA) surgery three years before. She was admitted to the hospital referring to three days of knee pain, restricted range of motion, and fever. Blood tests demonstrated leukocyte and C-reactive protein elevation. Joint fluid aspiration showed elevated white blood cell count with a high neutrophil differential and its conventional culture was positive for Streptococcus canis. She did not have pets but she took care of her daughter's dog. An acute haematogenous infection of the rTKA was diagnosed and treated with debridement, antibiotics (eight weeks of IV ceftriaxone), and implant retention (DAIR). After one year, the patient remains clinically asymptomatic without changes on X-rays and with normal serum levels of inflammatory blood markers. Streptococcus canis has to be kept in mind as a possible cause of haematogenous TKA infection in patients who have contact with domestic pets and patients should be asked for this contact. We recommend DAIR as a viable treatment option for this type of infection, which may show excellent results.

Performance characteristics of five antigen-detecting rapid diagnostic test (Ag-RDT) for SARS-CoV-2 asymptomatic infection: a head-to-head benchmark comparison.

BACKGROUND: Mass testing for early identification and isolation of infectious COVID-19 individuals is efficacious for reducing disease spread. Antigen-detecting rapid diagnostic tests (Ag-RDT) may be suitable for testing strategies; however, benchmark comparisons are scarce. METHODS: We used 286 nasopharyngeal specimens from unexposed asymptomatic individuals collected between December 2020 and January 2021 to assess five Ag-RDTs marketed by Abbott, Siemens, Roche Diagnostics, Lepu Medical, and Surescreen. RESULTS: For the overall sample, the performance parameters of Ag-RDTs were as follows: Abbott assay, sensitivity 38.6% (95%CI 29.1-48.8) and specificity 99.5% (97-100%); Siemens, sensitivity 51.5% (41.3-61.6) and specificity 98.4% (95.3-99.6); Roche, sensitivity 43.6% (33.7-53.8) and specificity 96.2% (92.4-98.5); Lepu, sensitivity 45.5% (35.6-55.8) and specificity 89.2% (83.8-93.3%); Surescreen, sensitivity 28.8% (20.2-38.6) and specificity 97.8% (94.5-99.4%). For specimens with cycle threshold (Ct) <30 in RT-qPCR, all Ag-RDT achieved a sensitivity ≥70%. The modelled negative- and positive-predictive value for 1% prevalence were >99% and <50%, respectively. CONCLUSIONS: When screening unexposed asymptomatic individuals, two Ag-RDTs achieved sensitivity ≥80% for specimens with Ct<30 and specificity ≥96%. The estimated negative predictive value suggests the suitability of Ag-RDTs for mass screenings of SARS-CoV-2 infection in the general population.

Macrolide resistance and molecular typing of Mycoplasma pneumoniae infections during a 4 year period in Spain.

BACKGROUND: Mycoplasma pneumoniae (MP) causes community-acquired pneumonia affecting mainly children, and tends to produce cyclic outbreaks. The widespread use of macrolides is increasing resistance rates to these antibiotics. Molecular tools can help in diagnosis, typing and resistance detection, leading to better patient management. OBJECTIVES: To assess the MP genotypes and resistance pattern circulating in our area while comparing serological and molecular diagnosis of MP. METHODS: Molecular and serological diagnosis of MP was performed in 821 samples collected in Badalona (Barcelona, Spain) from 2013 to 2017. Multiple locus variable number tandem repeat analysis (MLVA) and macrolide resistance detection by pyrosequencing were performed in those cases positive by PCR. Presence of respiratory viruses and relevant clinical data were also recorded. RESULTS: MP was detected in 16.8% of cases by PCR, with an overall agreement with serology of 76%. Eleven different MLVA types were identified, with 4-5-7-2 (50.1%) and 3-5-6-2 (29.2%) being the most abundant, with the latter showing a seasonal increase during the study. A total of 8% of the strains harboured a point substitution associated with macrolide resistance, corresponding mainly to an A2063G 23S rRNA mutation and directly related to previous macrolide therapy. Analysis of respiratory viruses showed viral coinfections in most cases. CONCLUSIONS: Serological and molecular tools combined could improve MP diagnosis and the analysis of its infection patterns. Macrolide resistance is associated with previous therapy. Given that MP pneumonia usually resolves spontaneously, it should be reconsidered whether antibiotic treatment is suitable for all cases.

Accessory gene regulator (Agr) functionality in Staphylococcus aureus derived from lower respiratory tract infections.

OBJECTIVE: Characterization of Staphylococcus aureus clinical isolates derived from lower respiratory tract infections (LRTIs), and correlation between the functionality of the accessory gene regulator (Agr) and genotypic and phenotypic characteristics, clinical variables and clinical outcome. METHODS: S aureus isolates derived from LRTIs and control groups (nasal carriage and bacteraemia) were genotyped using StaphyType DNA microarray. Agr activity was evaluated using the CAMP synergistic haemolysis assay and the Vesicle Lysis Test (VLT). Discordant strains were analysed by quantitative reverse-transcriptase real-time PCR (qRT-PCR). RESULTS: Agr was functional in 79.7% and 84.5% of strains according to the CAMP and VLT assays respectively. Higher concordance with RNAIII expression measured by qRT-PCR was observed with the VLT assay (76.2%) compared with the CAMP assay (23.8%). No statistically significant differences were observed in Agr functionality between the study groups, nor the phenotypical/genotypical bacterial characteristics. No association between increased mortality/respiratory complications and Agr function was observed. CONCLUSIONS: Agr activity was high (82.2%) in isolates from LRTIs suggesting the importance of this global regulator in lower respiratory tract colonisation and infection. However, equally high Agr activity was observed in isolates derived from nasal carriage and bacteraemia, contradictory to previous observations. Agr functionality measured by the VLT assay was superior to CAMP assay.

Septic arthritis due to methylcyllin-resistant Staphylococcus aureus in adults.

INTRODUCTION: Septic arthritis due to methylcyllin resistant Staphylococcus aureus (MRSA) is a serious infection that has increased in incidence in the past 10years. METHODS: We conducted a retrospective study (1984-2011) in which a description of the clinical and epidemiological characteristics of MRSA arthritis in adults was performed and then compared to native joint infections caused by MRSA vs. methylcyllin sensitive Staphylococcus aureus (MSSA). RESULTS: Fourteen MRSA infections were included (7 native joint, 5 prosthetic and 2 bursae). No case was polyarticular. There was significant comorbidity, although none was associated to rheumatoid arthritis. Seven patients had bacteremia. Four required surgical treatment. Six died. When comparing the 7 patients with native joint MRSA infection with the 17 cases caused by MSSA, no significant differences in risk factors were seen, except more malignancies in the MRSA group. The infection was polyarticular in 7 cases (41%) of the MSSA group. Bacteremia was more frequent in the MRSA group (71.4 vs 58.8%). Empirical antibiotic was useful in 28.6% of MRSA cases versus 100% of MSSA cases. There was a greater tendency to associated mortality in MRSA arthritis (57.1% vs 17.6%, P=.07). CONCLUSIONS: MRSA septic arthritis is a serious condition that occurs in the elderly and patients with high comorbidity. It is usually monoarticular, with positive blood cultures and higher mortality than MSSA arthritis. In patients at risk, vancomycin empiric antibiotic therapy is indicated.

Risk factors and prognosis of nosocomial bloodstream infections caused by extended-spectrum-beta-lactamase-producing Escherichia coli.

Extended-spectrum-beta-lactamase (ESBL)-producing Escherichia coli (ESBLEC) is an increasing cause of community and nosocomial infections worldwide. However, there is scarce clinical information about nosocomial bloodstream infections (BSIs) caused by these pathogens. We performed a study to investigate the risk factors for and prognosis of nosocomial BSIs due to ESBLEC in 13 Spanish hospitals. Risk factors were assessed by using a case-control-control study; 96 cases (2 to 16% of all nosocomial BSIs due to E. coli in the participating centers) were included; the most frequent ESBL was CTX-M-14 (48% of the isolates). We found CTX-M-15 in 10% of the isolates, which means that this enzyme is emerging as a cause of invasive infections in Spain. By repetitive extragenic palindromic sequence-PCR, most isolates were found to be clonally unrelated. By multivariate analysis, the risk factors for nosocomial BSIs due to ESBLEC were found to be organ transplant (odds ratio [OR]=4.8; 95% confidence interval [CI]=1.4 to 15.7), the previous use of oxyimino-beta-lactams (OR=6.0; 95% CI=3.0 to 11.8), and unknown BSI source (protective; OR=0.4; 95% CI=0.2 to 0.9), and duration of hospital stay (OR=1.02; 95% CI=1.00 to 1.03). The variables independently associated with mortality were a Pitt score of >1 (OR=3.9; 95% CI=1.2 to 12.9), a high-risk source (OR=5.5; 95% CI=1.4 to 21.9), and resistance to more than three antibiotics, apart from penicillins and cephalosporins (OR=6.5; 95% CI=1.4 to 30.0). Inappropriate empirical therapy was not associated with mortality. We conclude that ESBLEC is an important cause of nosocomial BSIs. The previous use of oxyimino-beta-lactams was the only modifiable risk factor found. Resistance to drugs other than penicillins and cephalosporins was associated with increased mortality.

[Social characteristics, risk behaviours and differences in the prevalence of HIV/sexually transmitted infections between Spanish and immigrant female sex workers in Catalonia, Spain]. / Diferencias en las características sociales, conductas de riesgo y prevalencia de infección por el virus de la inmunodeficiencia humana e infecciones de transmisión sexual entre trabajadoras del sexo españolas e inmigrantes en Cataluña.

BACKGROUND AND OBJECTIVE: To describe and compare the social characteristics, human immunodeficiency virus (HIV), Chlamydia trachomatis and Neisseria gonorrhoae prevalences, and risk behaviours among immigrant female sex workers (FSW) according to their geographical area of origin. MATERIAL AND METHOD: Cross-sectional study in an opportunistic sample of FSW in Catalonia in 2005 using an anonymous questionnaire. Oral fluid and urine samples were collected to determine the prevalence of HIV and C. trachomatis/N. gonorrhoeae, respectively. RESULTS: Four hundred women participated in the study; 10.8% from Spain, 32.5% from Eastern Europe, 30.7% from Latin America, and 26% from Africa. The majority of them (95.5%) always used condoms during vaginal intercourse with clients, but only 12.4% with steady partners. Overall HIV, C. trachomatis and N. gonorrhoeae prevalences were 1.8%, 5.5% and 0.6%, respectively. Spanish women injected drugs more frequently (9.3%), and used condoms less commonly (85.7% used condoms consistently) (p < 0.05). We observed differences in HIV prevalence only (9.3% among Spanish FSW; p < 0.01). CONCLUSIONS: To insist on consistent condom use with clients and steady partners has to become a prevention strategy. Spanish FSW need special attention because they reported less use of condoms and highest HIV prevalences.

Serum concentrations of procalcitonin after cardiac surgery.

BACKGROUND AND AIM: Monitoring of complications in patients undergoing cardiac surgery may be difficult because cardiopulmonary bypass (CPB) can lead to a systemic inflammatory response syndrome because of exposure of blood to nonphysiological surfaces. The purpose of the study was to establish the baseline levels of procalcitonin (PCT) after cardiac surgery in our population in order to analyze a possible induction of the inflammatory response that might interfere with the diagnosis of infection by PCT. METHODS: Serum samples from patients undergoing coronary artery bypass grafting or valve replacement were collected at the time of admission to intensive care unit, after surgery as well as in the first and second postoperative days. Patients were followed for the development of postoperative complications. PCT levels were measured by immunoluminometric assay. RESULTS: The mean PCT values were significantly higher in the first postoperative day in all the groups except the control group. No increased PCT levels were found related neither to duration of CPB, nor to time of aortic clamping. Only patients who presented complications had significantly increased PCT values immediately after surgery (p = 0.004), in the first postoperative day (p < 0.0001), and in the second postoperative day (p < 0.0001) with respect to those who recovered uneventfully. CONCLUSIONS: A slight and transient increase in PCT levels was observed in the first postoperative day after cardiac surgery. Significant elevation of PCT was only observed when complications were present.

Comparison of stool antigen immunoassay methods for detecting Helicobacter pylori infection before and after eradication treatment.

The aim of the study was to compare 6 stool antigen immunoassays for detecting Helicobacter pylori before and after eradication treatment. We compared 3 enzyme immunoassay (EIA) and 3 monoclonal immunochromatographic assays in diagnosing infection and in determining H. pylori status after eradication treatment. We evaluated stool samples from 80 patients diagnosed with H. pylori infection and from 18 patients without infection. To confirm H. pylori eradication, we evaluated 40 patients who received H. pylori treatment. The sensitivity and specificity were 87.3% and 83.3% for Immundiagnostik ELISA, 92.5% and 72.2% for HpSA EIA test, 95% and 66.6% for HpStAR EIA, 83.8% and 66.6% for H. pylori Letitest, 52.5% and 94.4% for ImmunoCard HpSA, and 78.8% and 55.5% for RAPID HpStAR, respectively. From the 40 patients evaluated 6 weeks after eradication therapy, the best agreement between the urea breath tests and immunoassay tests was with HpStAR EIA (90%) and H. pylori Letitest (85%). HpStAR EIA and H. pylori Letitest could be used as a routine diagnostic tool in the microbiology laboratory for assessing clinical significance and eradication control of H. pylori infection.

Prevalence of human immunodeficiency virus, Chlamydia trachomatis, and Neisseria gonorrhoeae and risk factors for sexually transmitted infections among immigrant female sex workers in Catalonia, Spain.

OBJECTIVES: To determine the prevalence of human immunodeficiency virus (HIV), Chlamydia trachomatis (CT), and Neisseria gonorrhoeae (NG) among immigrant female sex workers (FSW) according to their geographic area of origin and identify possible risk factors independently associated with current infection with CT and/or NG. STUDY DESIGN: Cross-sectional study of 357 FSW in Catalonia in 2005. Information on sociodemographic and sex work characteristics, use of alcohol and drugs, sexual practices, and the use of social and health care services was collected. Oral fluid and urine samples were collected to determine the prevalence of HIV and CT/NG, respectively. Factors independently associated with CT/NG were assessed using multivariate logistic regression models. RESULTS: A total of 36.4% of women were from Eastern Europe, 34.5% from Latin America, and 29.1% from Africa. Overall CT and NG prevalence were 5.9% [95% confidence interval (CI): 3.7-8.9] and 0.6% (95% CI: 0.1-2.0), respectively. No differences were observed by geographic origin. Three African women were HIV positive (overall HIV prevalence was 0.8%, 95% CI: 0.2-2.4). In multivariate analysis, younger age and unprotected sex with clients were associated with the presence of CT/NG. CONCLUSIONS: The prevalence of sexually transmitted infections among FSW in Catalonia was lower than in other European countries. Even though the prevalence of HIV was only 0.8%, it could increase in the future given the high vulnerability of these women and their wide geographic mobility. It is necessary to continue with the work carried out by nongovernmental organizations (harm reduction programs, outreach programs, and safe sex workshops) as well as to facilitate the access to health centers, especially for the youngest women.

Comparative evaluation of the new version of the INNO-LiPA Mycobacteria and genotype Mycobacterium assays for identification of Mycobacterium species from MB/BacT liquid cultures artificially inoculated with Mycobacterial strains.

The performance of two DNA line probe assays, a new version of INNO-LiPA Mycobacteria (Innogenetics, Ghent, Belgium) and the GenoType Mycobacterium (Hain Diagnostika, Nehren, Germany), were evaluated for identification of mycobacterial species isolated from liquid cultures. Both tests are based on a PCR technique and designed for simultaneous identification of different mycobacterial species by reverse hybridization and line probe technology. The INNO-LiPA Mycobacteria v2 targeting the 16S-23S rRNA gene spacer region was developed for the simultaneous identification of 16 different mycobacterial species. The GenoType Mycobacterium, which targets the 23S rRNA gene, allows simultaneous identification of 13 mycobacterial species. Both tests were evaluated on 110 mycobacterial strains belonging to 22 different mycobacterial species (20 reference strains, 83 clinical strains, and 4 Mycobacterium kansasii strains isolated from tap water) that were previously inoculated into MB/BacT bottles. The sensitivity of both methods, defined as the number of positive results obtained with the Mycobacterium genus probe together with an interpretable result on the number of samples tested was 110 of 110 (100%) for INNO-LiPA and 102 of 110 (92.7%) for GenoType. For samples with interpretable results, INNO-LiPA was able to correctly identify 109 of 110 samples (99.1%), whereas the GenoType correctly identified 100 of 102 samples (98.0%). Both tests were easy to perform, rapid, and reliable when applied to mycobacterial identification directly from MB/BacT bottles.