Diagnosis and antibiotic treatment of group a streptococcal pharyngitis in children in a primary care setting: impact of point-of-care polymerase chain reaction.

BACKGROUND: To compare the sensitivity and specificity of the recommended 2-step rapid antigen detection test (RADT) with confirmatory culture vs the point-of-care (POC) polymerase chain reaction (PCR) Roche cobas® Liat® Strep A test for detection of group A Streptococcus (GAS) in pediatric patients with pharyngitis, and to investigate the impact of these tests on antibiotic use in a large pediatric clinic. METHODS: This prospective, open-label study was conducted at a single site during fall/winter 2016-2017. A total of 275 patients aged 3 to 18 years with symptoms of pharyngitis had a throat-swab specimen analyzed using RADT, POC PCR, and culture. The sensitivity, specificity, and percentage agreement (95% CI) between assays and a laboratory-based nucleic acid amplification test were calculated. DNA sequencing was used to adjudicate discrepancies. The RADT or POC PCR result was provided to clinicians on alternating weeks to compare the impact on antibiotic use. RESULTS: A total of 255 samples were evaluated; 110 (43.1%) were GAS positive. Sensitivities (95% CI) for POC PCR, RADT, and culture were 95.5% (89.7-98.5%), 85.5% (77.5-1.5%), and 71.8% (62.4-80.0%), respectively. Specificities (95% CI) for POC PCR, RADT, and culture were 99.3% (96.2-99.98%), 93.7% (88.5-97.1%), and 100% (97.5-100%), respectively. Compared with RADT, POC PCR resulted in significantly greater appropriate antibiotic use (97.1% vs 87.5%; P = .0065). CONCLUSION: Under real-world conditions, RADT results were less specific and culture results were less sensitive than found in established literature and led to increased rates of inappropriate antibiotic use. POC PCR had high sensitivity and specificity and rapid turnaround times, and led to more appropriate antibiotic use. TRIAL REGISTRATION: ID number ISRCTN84562679 . Registered October 162,018, retrospectively registered.

A rationale for combination ampicillin and daptomycin in renal transplant patients with enterococcal infective endocarditis.

Treatment of enterococcal endocarditis in patients with history of renal transplantation is complicated. Treatment failure and/or drug toxicities are not uncommon. Treatment with ampicillin and daptomycin in a renal transplant patient has been rarely reported. Here we report a patient who was successfully treated with this novel combination.

Talaromyces marneffei infection in a non-HIV non-endemic population.

Introduction: Talaromyces marneffei infection is a systemic mycosis, caused by a dimorphic fungus, an opportunistic pathogen formerly known as Penicillium marneffei. This disease is endemic to Southeast Asia and common in human immunodeficiency virus (HIV) infected patients with low CD4 counts. Here we present a very rarely reported case of Talaromyces marneffei infection in an apparent non-immunosuppressed patient presenting decades later in a non-endemic setting (United States). Presentation of case: Our patient was a 75-year-old Caucasian Navy veteran, who served in Vietnam as a part of the Swift Boat service in 1966. He presented to his primary care provider with uncontrolled nonproductive cough and abnormal chest computerized tomography. Bronchoscopy specimens showed Talaromyces. He was empirically treated with itraconazole and then switched to voriconazole after confirmation of diagnosis but he later deteriorated was changed to liposomal amphotericin B and isavuconazole. Patient did well for the next 90 days on isavuconazole until the therapy was stopped. Soon after stopping the medication (isavuconazole) his symptoms recurred and ultimately patient expired. Discussion: Talaromycosis generally presents as pulmonary infection with manifestations similar with other endemic fungi. It is often seen HIV patients with travel to South east Asia. Very rarely this infection is seen and reported in non-immunosuppressed and in non-endemic areas. To date there are 4 well-documented cases among non-HIV, non-endemic population. Conclusion: Talaromyces can cause infection in non-HIV and non-endemic population and could be an underrecognized cause of pulmonary infections among veterans with even a remote history of exposure to the organism during deployment.

Dipping into the Clostridium difficile pool: Are alcohol-based dispensers fomites for C difficile?

The purpose of this study was to evaluate alcohol-based dispensers as potential fomites for Clostridium difficile. A convenience sample of 120 alcohol-based dispensers was evaluated for the presence of C difficile either by culture or polymerase chain reaction for C difficile toxin. The results demonstrated that C difficile was not cultured, and C difficile toxin was not detected using polymerase chain reaction; however, gram-positive rods, Clostridium perfringens, Pantoea agglomerans, coagulase-negative Staphylococcus, Peptostreptococcus, Bacillus spp, and microaerophilic Streptococcus were present within the overflow basins of the alcohol-based dispensers.

Development of a Multilocus Sequence Typing System for Medically Relevant Bipolaris Species.

Multilocus sequence typing (MLST) is the gold standard genotyping technique for many microorganisms. This classification approach satisfies the requirements for a high-resolution, standardized, and archivable taxonomic system. Here, we describe the development of a novel MLST system to assist with the investigation of an unusual cluster of surgical site infections caused by Bipolaris spp. in postoperative cardiothoracic surgery (POCS) patients during January 2008 to December 2013 in the southeastern United States. We also used the same MLST system to perform a retrospective analysis on isolates from a 2012 Bipolaris endophthalmitis outbreak caused by a contaminated product. This MLST system showed high intraspecies discriminatory power for Bipolaris spicifera, B. hawaiiensis, and B. australiensis. Based on the relatedness of the isolates, the MLST data supported the hypothesis that infections in the POCS cluster were from different environmental sources while confirming that the endophthalmitis outbreak resulted from a point source, which was a contaminated medication.

Infection with a chlorophyllic eukaryote after a traumatic freshwater injury.

Infections with chlorophyllic algae are uncommon. Invasive infection with Desmodesmus armatus developed in two patients independently after they each sustained a penetrating freshwater injury.

Multicenter evaluation of the Verigene Clostridium difficile nucleic acid assay.

The Verigene Clostridium difficile Nucleic Acid test (Verigene CDF test) (Nanosphere, Northbrook, IL) is a multiplex qualitative PCR assay that utilizes a nanoparticle-based array hybridization method to detect C. difficile tcdA and tcdB in fecal specimens. In addition, the assay detects binary toxin gene sequences and the single base pair deletion at nucleotide 117 (Δ 117) in tcdC to provide a presumptive identification of the epidemic strain 027/NAP1/BI (referred to here as ribotype 027). This study compared the Verigene CDF test with anaerobic direct and enriched toxigenic culture on stool specimens from symptomatic patients among five geographically diverse laboratories within the United States. The Verigene CDF test was performed according to the manufacturer's instructions, and the reference methods performed by a central laboratory included direct culture onto cycloserine cefoxitin fructose agar (CCFA) and enriched culture using cycloserine cefoxitin mannitol broth with taurocholate and lysozyme. Recovered isolates were identified as C. difficile using gas liquid chromatography and were tested for toxin using a cell culture cytotoxicity neutralization assay. Strains belonging to ribotype 027 were determined by PCR ribotyping and bidirectional sequencing for Δ 117 in tcdC. A total of 1,875 specimens were evaluable. Of these, 275 specimens (14.7%) were culture positive by either direct or enriched culture methods. Compared to direct culture alone, the overall sensitivity, specificity, positive predictive value, and negative predictive value for the Verigene CDF test were 98.7%, 87.5%, 42%, and 99.9%, respectively. Compared to combined direct and enriched culture results, the sensitivity, specificity, positive predictive value, and negative predictive values of the Verigene CDF test were 90.9%, 92.5%, 67.6%, and 98.3%, respectively. Of the 250 concordantly culture-positive specimens, 59 (23.6%) were flagged as "hypervirulent"; 53 were confirmed as ribotype 027, and all 59 possessed Δ 117 in tcdC. Time to results was approximately 2.5 h per specimen. The Verigene CDF test is a novel nucleic acid microarray that reliably detects both C. difficile toxins A and B in unformed stool specimens and appears to adequately identify ribotype 027 isolates.

Multilaboratory study of the Biomic automated well-reading instrument versus MicroScan WalkAway for reading MicroScan antimicrobial susceptibility and identification panels.

This study compared the Biomic automated well reader results to the MicroScan WalkAway results for reading MicroScan antimicrobial susceptibility and identification panels at four different sites. Routine fresh clinical isolates and quality control (QC) organisms were tested at each study site. A total of 46,176 MicroScan panel drug-organism combinations were read. The Biomic category agreement for 3,117 Gram-negative bacteria was 98.4%, with 1.4% minor and 0.2% major discrepancies. The Biomic category agreement for 5,233 Gram-positive bacteria was 98.7%, with 0.9% minor, 0.3% major, and 0.1% very major errors. Essential agreement, defined as Biomic results that were within ±1 2-fold dilution of the MicroScan results, was 99.3% for Gram-negative bacteria and 98.3% for Gram-positive bacteria. Biomic reading of MicroScan identification panels provided an overall agreement (first- and second-choice organism match) of 99.5% with 846 Gram-negative isolates and 99.5% with 430 Gram-positive isolates. These results suggest that the Biomic automated reader can provide accurate reading of MicroScan panels and has the capability of a visual panel read for manual adjustment of results.

Pleural infections: a 9-year review of bacteriology, case characteristics and mortality.

BACKGROUND: Despite advances in medical therapies, pleural infections remain a common disease. The characteristics of this disease seem to change over time, with alterations in patient characteristics and bacteriology. The purpose of this study was to provide a retrospective descriptive analysis of pleural infections during a 9-year period. METHODS: We performed a single-center retrospective review of all culture-positive pleural infections between January 2000 and December 2008. The primary outcome was assessment of long-term survival and associated independent risk factors affecting survival. Length of survival was determined using the Social Security Death Index. Case characteristics and bacteriology were reviewed for descriptive analysis. RESULTS: During a 9-year period, 187 culture-positive pleural infections were identified. Review of bacteriology revealed gram-positive cocci as the predominate organisms, most commonly Streptococcus and Staphylococcus. Anaerobes were found in 9.1% of the cases. Independent risk factors associated with risk of death based on multivariable survival analysis were age older than 65, cirrhosis and past and present malignancy. The hospital mortality was 10.7%, and the 1-year, 3-year and 5-year estimated survival rates were 73.8%, 63.3% and 60.6%, respectively. CONCLUSIONS: Pleural infections continue to remain a major health problem and carry significant morbidly and mortality. The importance of Staphylococcus aureus in this population has yet to be fully examined, and although potentially underestimated in this study, anaerobic infections remain a common pathogen.

Nocardia neocaledoniensis [corrected] as a cause of skin and soft tissue infection.

Nocardia neocaledoniensis was introduced as a new environmental species of Nocardia in 2004. We present the first case of human skin and soft tissue infection caused by this species in a patient with rheumatoid arthritis receiving prednisone and methotrexate therapy.

Multicenter evaluation of the LightCycler MRSA advanced test, the Xpert MRSA Assay, and MRSASelect directly plated culture with simulated workflow comparison for the detection of methicillin-resistant Staphylococcus aureus in nasal swabs.

Rapid detection of nasal colonization with methicillin-resistant Staphylococcus aureus (MRSA) followed by appropriate infection control procedures reduces MRSA infection and transmission. We compared the performance and workflow of two Food and Drug Administration-approved nucleic acid amplification assays, the LightCycler MRSA Advanced Test and the Xpert MRSA test, with those of directly plated culture (MRSASelect) using 1202 nasal swabs collected at three U.S. sites. The sensitivity of the LightCycler test (95.2%; 95% CI, 89.1% to 98.4%) and Xpert assay (99%; 95% CI, 94.8% to 100%) did not differ compared with that of culture; the specificity of the two assays was identical (95.5%; 95% CI, 94.1% to 96.7%) compared with culture. However, sequencing performed on 71 samples with discordant results among the three methods confirmed the presence of MRSA in 40% of samples that were positive by both molecular methods but negative by culture. Workflow analysis from all sites including batch runs revealed average hands-on sample preparation times of 1.40, 2.35, and 1.44 minutes per sample for the LightCycler, Xpert, and MRSASelect methods, respectively. Discrete event simulation analysis of workflow efficiencies revealed that the LightCycler test used less hands-on time for the assay when greater than eight batched samples were run. The high sensitivity and specificity, low hands-on time, and efficiency gains using batching capabilities make the LightCycler test suitable for rapid batch screening of MRSA colonization.

Universal MRSA nasal surveillance: characterization of outcomes at a tertiary care center and implications for infection control.

BACKGROUND: Recognition of methicillin-resistant Staphylococcus aureus (MRSA) nasal carriage by active surveillance cultures has been widely debated. Our institution implemented universal nasal screening by polymerase chain reaction (PCR) for MRSA and isolation of screen positive patients in December 2007. Here we present data about the correlation between screen positivity and subsequent development of infection and the impact of isolation on surgical site infection rates. METHODS: This was a retrospective, observational study from January 1, 2008, through June 30, 2008, on all inpatient admissions with a nasal MRSA PCR screen. Genotype of 15 MRSA blood isolates was determined utilizing the Diversilab® (bioMérieux, Hazelwood, MO) system. A phenotypic rule was deduced and utilized for analyzing all MRSA clinical isolates. RESULTS: 5375 patients were screened at ≤48 hours following admission. 581 MRSA positive nasal carriers (10.80%) were identified. 496 (85.3%) were asymptomatic MRSA nasal carriers. There were a total of 158 MRSA clinical infections. 85 (14.6%) MRSA nasal carriers had clinical infection. Of the 4794 (89.1%) non-nasally colonized patients, 73 (1.5%) had MRSA clinical infection. MRSA surgical site infection rate remained unchanged during the intervention period. Phenotypic predictive rule inferred 59.8% community-acquired MRSA (CA-MRSA) infections and 40% hospital-acquired MRSA (HA-MRSA) infections. CONCLUSIONS: Our study showed a positive correlation between having a nasal screen positivity and subsequent development of infection. Isolation of MRSA screen positive patients alone as an intervention did not reduce the surgical site infection rates. Since most of our isolates are CA-MRSA, our institution is implementing several new interventions to further reduce the incidence of HA-MRSA conditions.

Freshwater non-O1 Vibrio cholerae infection.

It is not appreciated by most physicians that vibrio infections can be acquired from freshwater exposure. A case of non-O1 Vibrio cholerae urinary tract infection associated with freshwater exposure is reported. The potential for vibrios to grow in brachish water and for summer heat to cause evaporation leading to relative increased salinity in freshwater bodies and the broad geographic range of these occurrences to include North American and both eastern and western Europe is noted. A literature review of vibrio infection acquired from freshwater exposure and the relationship to these epidemiologic and pathophysiologic events is discussed.

Brevibacillus brevis peritonitis.

We present what we believe is the first case of Brevibacillus (Bacillus) brevis peritonitis in a patient with hepatocellular carcinoma, possibly caused by the ingestion of fermented foods containing B. brevis spores. This case also demonstrates a pattern of antibiotic susceptibility with differing in vitro and in vivo bactericidal efficacy.

Pharmacokinetics of topical and intravenous cefazolin in patients with clean surgical wounds.

BACKGROUND: Surgical-site infection is a common postoperative nosocomial infection. Surgeons frequently treat operative patients with protective antibiotics and often choose cefazolin as the drug. Treatment schemes include both preoperative intravenous dosing and intraoperative dosing by irrigation. This study was designed to measure cefazolin concentrations both in serum and in wound drain fluid after intravenous dosing and after irrigation. METHODS: The authors conducted an institutional review board-approved study involving randomized allocation of breast reduction patients to group 1 (preoperative intravenous dosing) or group 2 (intraoperative dosing by irrigation). Each patient had serum and wound drainage specimens measured over time for cefazolin concentrations. Cefazolin dosing was based on preparations commonly used in the authors' hospital. Results from 24 patients are reported. RESULTS: Patients treated by conventional preoperative intravenous dosing displayed the expected serum degradation curve. These patients also demonstrated wound drainage concentrations (peak, 22.49 microg/ml) for approximately 4 to 5 hours. Measured concentrations were above the minimum therapeutic concentration (8 microg/ml) for Staphylococcus aureus. Patients treated by wound irrigation also demonstrated serum concentrations above minimum therapeutic concentration. In addition, these patients' wound drain fluid demonstrated very high cefazolin concentrations (peak, 4185.93 microg/ml), which remained high for 24 hours. CONCLUSIONS: Protective cefazolin concentrations in the wound can be achieved by both intravenous and irrigation delivery. Wound irrigation produces higher concentrations for longer periods of time.

Cluster of Mycobacterium fortuitum prosthetic joint infections.

Mycobacterium fortuitum is a member of the rapidly growing nontuberculous mycobacteria. Although mortality is rare from M. fortuitum, morbidity depends on the localized site of infection. M. fortuitum is ubiquitous in the environment and has been reported to cause infections of prosthetic devices. There have been seven previously reported cases of prosthetic joint infections due to M. fortuitum. This article presents three additional cases of postoperative joint infections due to M. fortuitum. All three cases were confirmed to be genetically indistinguishable by pulse-field gel electrophoresis. Awareness of its importance is especially noteworthy in the realm of ongoing antibiotic resistance.