PCR for detection of herpes simplex virus in cerebrospinal fluid: alternative acceptance criteria for diagnostic workup.

The determination of herpes simplex virus (HSV) infection using a PCR assay is one of the most commonly requested tests for analysis of cerebrospinal fluid (CSF), although only a very low proportion of results are positive. A previously reported study showed that selecting only those CSF samples with >5 leukocytes/mm(3) or a protein level of >50 mg/dl was adequate for the diagnostic workup. The aim of the present study was to assess the reliability of alternative acceptance criteria based on elevated CSF white blood cell counts (>10 cells/mm(3)). We analyzed all requests for HSV PCR received between January 2008 and December 2011. CSF samples were accepted for analysis if they had >10 cells/mm(3) or if the sample was from an immunocompromised patient or a child aged <2 years. In order to evaluate our selection criteria, we identified those CSF samples with a leukocyte count of 5 to 10 cells/mm(3) or protein levels of >50 mg/dl in order to test them for HSV type 1 and 2 (HSV-1 and HSV-2) DNA. During the study period, 466 CSF samples were submitted to the microbiology laboratory for HSV PCR. Of these, 268 (57.5%) were rejected, and 198 (42.5%) were tested according to our routine criteria. Of the tested samples, 11 (5.5%) were positive for HSV DNA (7 for HSV-1 and 4 for HSV-2). Of the 268 rejected specimens, 74 met the criteria of >5 cells/mm(3) and/or protein levels of >50 mg/dl. Of these, 70 (94.6%) were available for analysis. None of the samples yielded a positive HSV PCR result. Acceptance criteria based on CSF leukocyte counts, host immune status, and age can help to streamline the application of HSV PCR without reducing sensitivity.

Colonization of the nasal airways by Staphylococcus aureus on admission to a major heart surgery operating room: A real-world experience.

INTRODUCTION: Nasal swab culture is used to identify Staphylococcus aureus colonization, as this is a major risk factor for surgical site infection (SSI) in patients who are going to undergo major heart surgery (MHS). We determined nasal carriage of S. aureus in patients undergoing MHS by comparing the yield of a conventional culture with that of a rapid molecular test (Xpert® SA Nasal Complete, Cepheid). METHODS: From July 2015 to April 2017, all patients who were to undergo MHS were invited to participate in the study. We obtained two nasal cultures from each patient just before entering the operating room, independently of a previous test for the determination of nasal colonization by this microorganism performed before surgery. One swab was used for conventional culture in the microbiology laboratory, and the other was used for the rapid molecular test. We defined nasal colonization as the presence of a positive culture for S. aureus using either of the two techniques. All patients were followed up until hospital discharge or death. RESULTS: Overall, 57 out of 200 patients (28.5%) were colonized by S. aureus at the time of surgery. Thirty-three patients had both conventional culture- and PCR-positive results. Twenty-four patients had a negative culture and a positive PCR test. Only twenty-one percent (12/57) of colonized patients had undergone an attempt to decolonise before the surgical intervention. CONCLUSION: A significant proportion of patients undergoing MHS are colonized by S. aureus in the nostrils on entering the operating room. New strategies to prevent SSI by this microorganism are needed. Rapid molecular tests immediately before MHS, followed by immediate decolonisation, must be evaluated. Trial Registration Clinical Trials.gov NCT02640001.

Gradient diffusion antibiogram used directly on bronchial aspirates for a rapid diagnosis of ventilator-associated pneumonia.

Background: In patients with suspected ventilator-associated pneumonia, a rapid etiological diagnosis is crucial as incorrect or delayed treatment in the first few hours leads to a worse prognosis and a higher mortality rate. This study examines the efficacy of a rapid antibiogram on bronchial aspirates in patients with suspected ventilator-associated pneumonia (VAP). Methods: The direct gradient diffusion susceptibility testing method (GDM) on respiratory samples was compared with a standard broth microdilution method (BMD) after quantitative cultures in patients with suspicion of VAP. Samples were preselected by Gram staining (for good quality microbiological samples with a predominant single bacterial morphotype). The antibiotics tested were ceftazidime, ceftobiprole, ceftolozane-tazobactam, meropenem, doripenem, and tedizolid. Results: Over a 16-month study period, 445 bronchial aspirate samples were selected from 1376 samples received at our laboratory from 672 adult patients. By direct plating on Mueller-Hinton agar, we recovered 504 (95.5%) of the 528 microorganisms identified by the standard semiquantitative method. Antimicrobial susceptibility testing by GDM was compared with the BMD method in 472 strains (216 Enterobacteriaceae, 138 P. aeruginosa and 118 S. aureus.) and 1652 individual microorganism-antimicrobial agent combinations. There was total agreement between both methods in 98% of combinations. The Kappa index between both techniques was excellent (over 80%). There was only one potential major error for P. aeruginosa susceptibility to ceftazidime. Conclusions: The six GDM strips directly placed on plated bronchial aspirates obtained from patients with a suspicion of VAP provided accurate and reliable susceptibility results within 24 h.

Differences between a probable and proven BCG infection following intravesical instillations: 16 years experience in a tertiary care hospital.

BACKGROUND: Intravesical instillation of Bacillus Calmette-Guérin (BCG) is an efficient immunotherapy for superficial bladder cancer. BCG infection represents a major yet uncommon adverse event that occurs in 5-10% of the patients treated with BCG instillations, though the pathogenesis of this entity is not clear. METHODS: We report two cases of patients presented at our institution with BCG infection after instillation: one with microbiological BCG isolate and another without, and review all the medical records of patients instilled with BCG in our institution from 1996 until 2012, comparing patients with probable and proven BCG infection. RESULTS: During the study period, a total of 786 patients received BCG intravesical instillations. Of them, 31 (4%) patients had to suspend treatment because of adverse events and, specifically, 11 (1.3%) patients had to interrupt treatment because of suspected BCG infection. The incidence of BCG infection during our study period was 0.87 episodes per 1,000 instilled patients/year and 140 cases per 10,000 instilled patients. Of the 11 patients with suspected BCG infection, 7 (64%) had a probable BCG infection, while 4 (36%) patients had a proven BCG infection. All patients with a proven infection had a previous underlying condition, compared to a high proportion of patients with probable infection (57%) that did not present with underlying diseases. Common findings between both groups of patients were abnormal imaging studies and laboratory tests. Regarding treatment, 8 (73%) of the 11 patients with BCG infection received at least two first line drugs active against M. bovis (isoniazid, rifampicin or ethambutol), four patients (36%) received steroids as part of the treatment and curation was obtained in 10 (91%) patients, while 1 patient with a proven infection had a death related to BCG infection. CONCLUSIONS: We can conclude that BCG infection after intravesical instillations has a low incidence in our institution. Patients with previous underlying conditions seem to have more proven infections. A high proportion of patients do not yield positive microbiological tests; in those cases the diagnosis relies in clinical, radiological and laboratory findings. Treatment for BCG infection should include at least two active drugs against M. bovis and coadjuvant steroid treatment for systemic BCG infections.

Characteristics and Outcome of Streptococcus pneumoniae Endocarditis in the XXI Century: A Systematic Review of 111 Cases (2000-2013).

Streptococcus pneumoniae is an infrequent cause of severe infectious endocarditis (IE). The aim of our study was to describe the epidemiology, clinical and microbiological characteristics, and outcome of a series of cases of S. pneumoniae IE diagnosed in Spain and in a series of cases published since 2000 in the medical literature. We prospectively collected all cases of IE diagnosed in a multicenter cohort of patients from 27 Spanish hospitals (n = 2539). We also performed a systematic review of the literature since 2000 and retrieved all cases with complete clinical data using a pre-established protocol. Predictors of mortality were identified using a logistic regression model. We collected 111 cases of pneumococcal IE: 24 patients from the Spanish cohort and 87 cases from the literature review. Median age was 51 years, and 23 patients (20.7%) were under 15 years. Men accounted for 64% of patients, and infection was community-acquired in 96.4% of cases. The most important underlying conditions were liver disease (27.9%) and immunosuppression (10.8%). A predisposing heart condition was present in only 18 patients (16.2%). Pneumococcal IE affected a native valve in 93.7% of patients. Left-sided endocarditis predominated (aortic valve 53.2% and mitral valve 40.5%). The microbiological diagnosis was obtained from blood cultures in 84.7% of cases. In the Spanish cohort, nonsusceptibility to penicillin was detected in 4.2%. The most common clinical manifestations included fever (71.2%), a new heart murmur (55%), pneumonia (45.9%), meningitis (40.5%), and Austrian syndrome (26.1%). Cardiac surgery was performed in 47.7% of patients. The in-hospital mortality rate was 20.7%. The multivariate analysis revealed the independent risk factors for mortality to be meningitis (OR, 4.3; 95% CI, 1.4-12.9; P < 0.01). Valve surgery was protective (OR, 0.1; 95% CI, 0.04-0.4; P < 0.01). Streptococcus pneumoniae IE is a community-acquired disease that mainly affects native aortic valves. Half of the cases in the present study had concomitant pneumonia, and a considerable number developed meningitis. Mortality was high, mainly in patients with central nervous system (CNS) involvement. Surgery was protective.

A multicenter multinational study of abdominal candidiasis: epidemiology, outcomes and predictors of mortality.

PURPOSE: Clinical data on patients with intra-abdominal candidiasis (IAC) is still scarce. METHODS: We collected data from 13 hospitals in Italy, Spain, Brazil, and Greece over a 3-year period (2011-2013) including patients from ICU, medical, and surgical wards. RESULTS: A total of 481 patients were included in the study. Of these, 27% were hospitalized in ICU. Mean age was 63 years and 57% of patients were male. IAC mainly consisted of secondary peritonitis (41%) and abdominal abscesses (30%); 68 (14%) cases were also candidemic and 331 (69%) had concomitant bacterial infections. The most commonly isolated Candida species were C. albicans (n = 308 isolates, 64%) and C. glabrata (n = 76, 16%). Antifungal treatment included echinocandins (64%), azoles (32%), and amphotericin B (4%). Septic shock was documented in 40.5% of patients. Overall 30-day hospital mortality was 27% with 38.9% mortality in ICU. Multivariate logistic regression showed that age (OR 1.05, 95% CI 1.03-1.07, P < 0.001), increments in 1-point APACHE II scores (OR 1.05, 95% CI 1.01-1.08, P = 0.028), secondary peritonitis (OR 1.72, 95% CI 1.02-2.89, P = 0.019), septic shock (OR 3.29, 95% CI 1.88-5.86, P < 0.001), and absence of adequate abdominal source control (OR 3.35, 95% CI 2.01-5.63, P < 0.001) were associated with mortality. In patients with septic shock, absence of source control correlated with mortality rates above 60% irrespective of administration of an adequate antifungal therapy. CONCLUSIONS: Low percentages of concomitant candidemia and high mortality rates are documented in IAC. In patients presenting with septic shock, source control is fundamental.