Hannah Sprecher

Diagnostic Accuracy of PCR Alone Compared to Galactomannan in Bronchoalveolar Lavage Fluid for Diagnosis of Invasive Pulmonary Aspergillosis: a Systematic Review

ABSTRACT PCR in bronchoalveolar lavage (BAL) fluid has not been accepted as a diagnostic criterion for invasive pulmonary aspergillosis (IPA). We conducted a systematic review assessing the diagnostic accuracy of PCR in BAL fluid with a direct comparison versus galactomannan (GM) in BAL fluid. We included prospective and retrospective cohort and case-control studies. Studies were included if they used the EORTC/MSG consensus definition criteria of IPA and assessed ≥80% of patients at risk for IPA. Two reviewers abstracted data independently. Risk of bias was assessed using QUADAS-2. Summary sensitivity and specificity values were estimated using a bivariate model and reported with a 95% confidence interval (CI). Nineteen studies published between 1993 and 2012 were included. The summary sensitivity and specificity values (CIs) for diagnosis of proven or probable IPA were 90.2% (77.2 to 96.1%) and 96.4% (93.3 to 98.1%), respectively. In nine cohort studies strictly adherent to the 2002 or 2008 EORTC/MSG criteria for reference standard definitions, the summary sensitivity and specificity values (CIs) were 77.2% (62 to 87.6%) and 93.5% (90.6 to 95.6%), respectively. Antifungal treatment before bronchoscopy significantly reduced sensitivity. The diagnostic performance of PCR was similar to that of GM in BAL fluid using an optical density index cutoff of 0.5. If either PCR or GM in BAL fluid defined a positive result, the pooled sensitivity was higher than that of GM alone, with similar specificity. We conclude that the diagnostic performance of PCR in BAL fluid is good and comparable to that of GM in BAL fluid. Performing both tests results in optimal sensitivity with no loss of specificity. Results are dependent on the reference standard definitions.

Meningitis following spinal anesthesia: 6 cases in 5 years.

We describe 6 cases of meningitis after spinal anesthesia associated with a single anesthesiologist over the course of 5 years. The earliest case occurred in 2000, and the other 5 cases occurred over the course of 14 months in 2004-2005. The case identified in 2000 was culture-positive for Streptococcus salivarius. The other 5 cases were culture-negative for this organism but in 2 cases, the cerebrospinal fluid was found to be positive for bacterial DNA that was identified as belonging to S. salivarius by sequencing of the 16S rRNA gene. The association with a single anesthesiologist and a single hospital during a relatively short interval, however, lead us to believe that these occurrences are part of a series associated with possible violations of aseptic technique.

An outbreak of Mycobacterium mucogenicum bacteremia in pediatric hematology-oncology patients.

Background and Aims: Mycobacterium mucogenicum (MM) is a rapidly growing nontuberculous mycobacterium that is commonly identified in tap water that can rarely cause bacteremia. We describe an outbreak of MM bacteremia among pediatric hematology-oncology patients. Methods: Charts of children with MM bacteremia were retrospectively reviewed. Demographic data, underlying conditions, central venous catheter (CVC) type, duration of bacteremia, and treatment were retrieved. Epidemiologic investigation was conducted during the outbreak including environmental sampling. Results: During an 8-month period (September 2005–May 2006), 8 patients aged 1.5 to 17 years had MM bacteremia. Seven patients had underlying malignancy and 1 with thalassemia major had bone marrow transplantation. The mean number of positive blood cultures was 4.2 (1–11) per patient. Two patients received antibiotic treatment in addition to removal of CVC. All patients were cured. Almost 60 environmental samples were obtained from surfaces, ice, and municipal water supply. All were negative and no source was documented. Infection control measures included emphasis on guidelines for prevention of CVC-associated infections. No cases occurred before and after this outbreak. Conclusions: MM is a rare agent of CVC-associated bacteremia. Removal of the CVC may be sufficient for management of bacteremia. In the absence of definite source identification, reinforcement of standard infection control measures can be successful in containing outbreaks.

Cutaneous nocardiosis: report of two cases and review of the literature.

Background  Cutaneous nocardiosis is an uncommon infectious disease that presents as a primary cutaneous infection or as a disseminated disease. It is often misdiagnosed because of its rarity and nonspecific clinical picture.

Values of C-reactive protein, procalcitonin, and Staphylococcus-specific PCR in neonatal late-onset sepsis

Aim: To evaluate the predictive value of relevant clinical and laboratory parameters (complete blood count (CBC), C‐reactive protein (CRP), procalcitonin (PCT) and Staphylococcus‐specific polymerase chain reaction (PCR)) in neonates with suspected late‐onset sepsis (LOS). Methods: NICU neonates were prospectively followed for septic events. One hundred and eleven neonates developed 148 suspected septic events beyond 3 d of age. We recorded the clinical signs and laboratory abnormalities at onset of sepsis, serum CRP and PCT, Staphylococcus‐specific PCR, microbiological data, and empiric antimicrobial therapy. Results: Variables significantly associated with subsequently confirmed LOS included hypotension (relative risk (RR) = 5.6, 95% CI 3.29–9.53), mechanical ventilation (RR = 2.46, 95% CI 1.24–4.86), immature/total neutrophil ratio (I/T) > 0.2 (RR = 5.13, 95% CI 2.54–10.31), CRP > 1.0 mg/dl (RR = 2.85, 95% CI 1.32–6.15), and small‐for‐gestational‐age (SGA) status (RR = 2.13, 95% CI 1.03–4.38). PCT was not significantly associated with LOS. For detection of staphylococcal bacteremia, Staphylococcus‐specific PCR showed: sensitivity 57.1%, specificity 94.7%, positive predictive value 53.3%, and negative predictive value 95.4%.

PCR-Based Diagnosis of Neonatal Staphylococcal Bacteremias

ABSTRACT We compared PCR with blood cultures in the diagnosis of neonatal staphylococcal sepsis. Significant association was observed between PCR-based and culture-based diagnosis of staphylococcal bacteremia. Positive and negative predictive values for PCR were 100% and 98%, respectively. These data indicate that PCR may serve as a useful adjunct for the rapid diagnosis of staphylococcal sepsis.

Fatal hospital-acquired Legionella pneumonia in a neonate.

Legionnaire disease is a rare cause of community-acquired pneumonia in children and an exceedingly rare diagnosis in infants and neonates, with only few reported cases. We describe a case of fatal Legionnaire disease diagnosed by culture and polymerase chain reaction method from sputum and lung biopsy specimens, and emphasize the importance of considering this rare entity in cases of severe neonatal pneumonia.

Acremonium Vertebral Osteomyelitis: Molecular Diagnosis and Response to Voriconazole

We present a case of Acremonium vertebral osteomyelitis that relapsed despite surgical debridement and prolonged treatment with liposomal amphotericin B, but which responded to voriconazole therapy. The report highlights the role of molecular diagnosis of rare fungal osteomyelitis. The patient was successfully treated with voriconazole.

Polymerase chain reaction-based detection of Pneumocystis jirovecii in bronchoalveolar lavage fluid for the diagnosis of pneumocystis pneumonia.

Introduction:The diagnosis of pneumocystis pneumonia (PCP) in non-human immunodeficiency virus (HIV)-infected immunocompromised patients is notoriously difficult. The recent advent of polymerase chain reaction (PCR)-based detection systems, based on the identification of single fungal genes, has markedly improved diagnostic accuracy in this ominous disease. In an attempt to further improve diagnostic yield, the authors used a PCR-based detection system for Pneumocystis jirovecii, based on targeting 3 distinct genes. Methods:During the 4-year period (January 2005 to January 2009), all consecutive immunocompromised patients suspected of having PCP in the differential diagnosis underwent bronchoscopy with bronchoalveolar lavage sampling for the evaluation of the etiology of pulmonary infiltrates. Bronchoalveolar fluid was tested for the presence of a wide variety of possible etiological microorganisms. Results:In a cohort of 214 immunocompromised patients (of which 198 were non-HIV immunocompromised patients) who underwent bronchoscopy with bronchoalveolar lavage for evaluation of pulmonary infiltrates, PCR correctly diagnosed PCP in 75% (42/56) compared with 14% (8/56) diagnosed by traditional stains, and increased diagnostic yield 5.4-fold. Conclusions:Given the absence of a sensitive gold standard, this study demonstrates the usefulness of a multigene PCR-based detection of Pneumocystis jirovecii DNA for supporting the clinical diagnosis of PCP, with high sensitivity and negative predictive value rates compared with direct stains, especially in non-HIV immunocompromised patients.

Clinical Impact of a PCR Assay for Rapid Identification of Klebsiella pneumoniae in Blood Cultures

ABSTRACT The clinical impact of a rapid PCR identification assay for Klebsiella pneumoniae in positive blood cultures was prospectively evaluated. Multivariate analysis identified the rapid PCR assay as the only significant factor in decreasing the time lapse preceding the initiation of appropriate antimicrobial therapy (hazards ratio, 3.03; confidence interval, 1.62 to 5.68; P, 0.001).