Evaluation of Sonicate Fluid Culture Cutoff Points for Periprosthetic Joint Infection Diagnosis.

Introduction: Implant sonication is useful for recovery of periprosthetic joint infection (PJI) pathogens in culture, but exact cutoff points for definition of clinically significant sonicate fluid culture results vary from study to study. The aim of this study was to define ideal sonicate fluid culture cutoff points for PJI diagnosis. Methods: Sonicate fluid cultures from hip and knee prosthesis components removed between February 2007 and December 2020 were studied. Prosthesis components were placed in solid containers in the operating room; in the clinical microbiology laboratory, 400 mL Ringer's solution was added, and containers subjected to vortexing, sonication and then vortexing, followed by centrifugation. Concentrated sonicate fluid was plated on aerobic and anaerobic solid media, and culture results reported semiquantitatively, as no growth, <20, 20-50, 51-100, or >100 CFU/10 mL sonicate fluid. Sonicate cultures from cement spacers and cultures yielding more than 1 microorganism were excluded. Sensitivity and specificity of each cutoff point was evaluated. Results: A total of 1448 sonicate fluid cultures were evaluated, 68% from knees and 32% from hips. PJI was present in 644 (44%) cases. Sensitivity of sonicate culture was 75.0% at <20 CFU/10 mL, 55.3% at ≥20 CFU/10 mL, 46.9% at >51 CFU/10 mL, and 39.8% at >100 CFU/10 mL. Specificity was 78.2%, 99.8%, 100%, and 100%, at the 4 cutoff points, respectively. Conclusions: A cutoff point for sonicate fluid culture positivity of ≥20 CFU/10 mL is suitable for PJI diagnosis.

Poor Sensitivity of the MALDI Biotyper® MBT Subtyping Module for Detection of Klebsiella pneumoniae Carbapenemase (KPC) in Klebsiella Species.

Rapid detection of Klebsiella pneumoniae carbapenemase (KPC) in the Klebsiella species is desirable. The MALDI Biotyper® MBT Subtyping Module (Bruker Daltonics) uses an algorithm that detects a peak at ~11,109 m/z corresponding to a protein encoded by the p019 gene to detect KPC simultaneously with organism identification by a matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-ToF MS). Here, the subtyping module was evaluated using 795 clinical Klebsiella isolates, with whole genome sequences used to assess for blaKPC and p019. For the isolates identified as KPC positive by sequencing, the overall sensitivity of the MALDI-ToF MS subtyping module was 239/574 (42%) with 100% specificity. For the isolates harboring p019, the subtyping module showed a sensitivity of 97% (239/246) and a specificity of 100%. The subtyping module had poor sensitivity for the detection of blaKPC-positive Klebsiella isolates, albeit exhibiting excellent specificity. The poor sensitivity was a result of p019 being present in only 43% of the blaKPC-positive Klebsiella isolates.

Tetanus, analysis of 29 cases.

BACKGROUND: Tetanus disease is caused by Clostridium tetani, an anaerobe bacteria found in dust and soil. Once reached human body through damaged tissues, C. tetani releases several neurotoxins which block the inhibitory function, leading to an increased muscle tone, ultimately causing respiratory failure. Severe tetanus is a life-threatening disease, especially in low-income-regions. METHODS: This is a retrospective case-series study, undertaken at two hospitals of Vigo (population area 600,000 inhabitants). Tetanus cases were identified through the discharge databases of both hospitals between the years 1995-2019. Epidemiological and clinical data were obtained from the patient's medical records. RESULTS: A total of 33 cases were identified; median age was 67 years, and most of patients were women (n=16, 55.2%). Generalized tetanus was the most common clinical course, and neck stiffness was the most frequent symptom. A total of 25 patients (86%) were admitted to the Intensive Care Unit, 21 required invasive ventilation and 2 patients died. DISCUSSION: The incidence of tetanus was low but most of cases were severe. Mortality was slightly higher than previously reported. Interestingly, the deceased patients were old-women, consistent with previously reported research in high-income-regions, while mortality in low-income-countries concentrates in middle-aged men.

Late onset prosthetic joint infection caused by Parvimonas micra.

Parvimonas micra (P.micra) is a difficult to culture gram positive anaerobic microorganism, typically found in the human microbiota, specially in the oral cavity. There are limited cases in literature reporting prosthetic joint infection due to this bacteria, although its isolation has been reported in different settings in later years. We present the case of a late onset knee prosthetic joint infection caused by Parvimonas micra in an 87 year old woman treated with antibiotics and two-step surgery with prosthetic material removal, antibiotic-loaded cement spacer placement and new prosthetic material replacement after 2 weeks of intravenous antimicrobial therapy followed by 6 weeks of oral therapy.

Outpatient Parenteral Antimicrobial Therapy With Ceftolozane/Tazobactam via Continuous Infusion for Multidrug-Resistant Pseudomonas aeruginosa Osteomyelitis.

We present a case of Pseudomonas aeruginosa osteomyelitis treated with surgery and antibiotic therapy with ceftolozane-tazobactam in continuous infusion at home using an elastomeric pump. We discuss the use of ceftolozane-tazobactam in continuous infusion administered at home as an effective alternative for the treatment of multidrug-resistant Pseudomonas aeruginosa osteomyelitis.

Treatment duration of complicated urinary tract infections by extended-spectrum beta-lactamases producing enterobacterales.

BACKGROUND: Urinary tract infections caused by extended-spectrum beta-lactamase producing Enterobacterales (ESBL-EB) are a problem increasing in our clinical practice. OBJECTIVES: The aim of this study was to evaluate the clinical outcome in patients who received short (≤ 7 days) versus long courses (>7 days) of antimicrobial therapy for complicated ESBL-EB urinary tract infections. METHODS: This is a retrospective and observational study. Positive urine cultures for ESBL-EB in our hospital between March 2015 and July 2017 were identified. Patients with complicated urinary tract infection were included. Differences between treatment groups (7 days or less vs more than 7 days) were analyzed according to baseline characteristics and severity of clinical presentation. Primary outcome was all cause 30-day mortality. Secondary outcome was a combined item of all cause mortality and reinfection by the same enterobacteria at 30 days. RESULTS: 273 urine cultures were positive for ESBL-EB during the study period. 75 episodes were included, 40 in the long treatment group and 35 in the short treatment group. Mean treatment duration in short and long treatment groups was 6,1 and 13,8 days respectively. Mortality at 30 days was 5,7% in the short treatment group and 5% in the long treatment group without significant differences (P = 0,8). Mortality or reinfection by the same ESBL-EB at 30 days was 8,6% in the short treatment group and 10% in the long treatment group, without significant differences (P = 0,8). CONCLUSIONS: Short courses of antimicrobial treatment seems to be effective as treatment of complicated urinary tract infections by ESBL-EB.

Pseudomonas aeruginosa urinary tract infections in hospitalized patients: Mortality and prognostic factors.

BACKGROUND: The aim of this study was to analyze the mortality and predictors of 30-day mortality among hospitalized patients with Pseudomonas aeruginosa urinary tract infection (PAUTI) and the impact of antibiotic treatment on survival. METHODS: Patients admitted to our hospital with PAUTI or those diagnosed of PAUTI during hospitalization for other disease between September 2012 and September 2014 were included. Repeated episodes from the same patient were excluded. Database with demographic, clinical and laboratory ítems was created. Empirical and definitive antibiotic therapy, antimicrobial resistance and all-cause mortality at 30 and 90 days were included. RESULTS: 62 patients were included, with a mean age of 75 years. 51% were male. Mortality was 17.7% at 30 days and 33.9% at 90 days. Factors associated with reduced survival at 30 days were chronic liver disease with portal hypertension (P<0,01), diabetes mellitus (P = 0,04) chronic renal failure (P = 0,02), severe sepsis or septic shock (P<0,01), Charlson index > 3 (P = 0.02) and inadequated definitive antibiotic treatment (P<0,01). Independent risk factors for mortality in multivariate analysis were advanced chronic liver disease (HR 77,4; P<0,01), diabetes mellitus (HR 3,6; P = 0,04), chronic renal failure (HR 4,1; P = 0,03) and inadequated definitive antimicrobial treatment (HR 6,8; P = 0,01). CONCLUSIONS: PAUTI are associated with high mortality in hospitalized patients, which increases significantly in those with severe comorbidity such as chronic renal failure, advanced liver disease or diabetes mellitus. Inadequated antibiotic treatment is associated with poor outcome, which remarks the importance of adjusting empirical antibiotic treatment based on the microbiological susceptibility results.

Alopecia areata as a paraneoplastic syndrome of gastric cancer.

Alopecia areata produces hair loss in circular patches by an immune mechanism. The association with hematologic malignancies and with digestive tumors has been described. We report the case of a man who presented alopecia areata and two months later he was diagnosed with gastric adenocarcinoma.