Fibroblast growth factor receptor 1 amplification in laryngeal squamous cell carcinoma.

Fibroblast growth factor receptor 1 (FGFR1) has been noted to be amplified in a variety of squamous cell carcinomas (SCCa) of the head, neck, and lung and increased copy number (CN) is a predictor of poor outcomes. FGFR1 is a therapeutic target for lung SCCa and inhibition therapy is currently in clinical trials. Absolute quantification of FGFR1 from formalin fixed paraffin embedded (FFPE) tissue of laryngeal SCCa was examined in this retrospective study. A droplet digital polymerase chain reaction (ddPCR) was used for absolute quantitation of the FGFR1 gene CN. Of the 74 samples analyzed, FGFR1 CN analysis revealed 54% of samples had CN greater than 2 copies/cell (1.8-2.2 copies/cell), and 38% had CN values greater than 3. The mean and standard deviation FGFR1 CN was 4.17 ± 1.46 CN for African American patients (n = 41) and 3.78 ±1.85 CN for Caucasian patients (n = 31). Further, 60.9% of specimens from African Americans demonstrated increased FGFR1 CN compared to 48.4% of Caucasians. Two SCCA samples from Native American demonstrated increased FGFR1 CN (4.19 and 3.01 CN). The level of FGFR1 amplification did not correlate with tumor stage, lymph node staging, or metastasis. In this population, the proportion of patient samples with an FGFR1 amplification was three times higher than in reported for SCCA of the head and neck. Further, increased FGFR1 CN was observed in two racial groups not previously reported: African Americans and Native Americans. However, FGFR1 amplification is not prognostic in laryngeal squamous cell carcinomas.

Mechanisms of fosfomycin resistance in carbapenem-resistant Enterobacter sp.

We report on fosfomycin susceptibility and mechanisms of resistance in clinical strains of blaKPC-positive Enterobacter sp. (n = 19). A total of 14 strains (74%) were susceptible to fosfomycin; 8 strains (42%) were positive for fosA and no strains were positive for FosA3 or FosC2. FosA presence does not appear to correlate with susceptibility.

Can contaminated water be rendered safe for nasal saline irrigations?

OBJECTIVES/HYPOTHESIS: To compare sterile water to three methods of sterilization (carbon filtration, boiling, and ultraviolet [UV] light) for preparation of nasal saline irrigants free of bacterial and amebic contaminants. STUDY DESIGN: Bench-top translational research and cost comparison. METHODS: Sterile water was compared to common sterilization methods. Sterile water was contaminated with known concentrations of Staphylococcus aureus, Pseudomonas aeruginosa, Moraxella catarrhalis, Acinetobacter baumannii, Klebsiella pneumonia, Legionella pneumophila, and Naegleria fowleri. Test samples were subjected to boiling, carbon filtration, or ultraviolet light (UV) and then cultivated on appropriate media. Controls included samples of sterile water (negative control) and untreated test samples (positive control). RESULTS: Carbon filtration reduced but did not eliminate the number of organisms present in test samples. Boiling test samples for 5 minutes and UV light treatment resulted in sterilization of all organisms. Negative (sham contaminated) samples produced no growth, whereas positive (untreated) samples grew numerous organisms as expected. A cost comparison between bottled water and UV water sterilization (with SteriPEN Ultra) became equal in less than 2 years of consistent use. CONCLUSIONS: Carbon filtration reduces contamination but does not sterilize water and is thus unsafe for preparation of nasal saline irrigant. Boiling and UV treatment resulted in sterilization and are equivalent to purchased sterile water. Ultraviolet treatment was found to be safe, convenient, and a cost-effective alternative to purchased sterile water. LEVEL OF EVIDENCE: NA Laryngoscope, 127:1513-1519, 2017.

Detection of methicillin-resistant Staphylococcus aureus by a duplex droplet digital PCR assay.

Health care-associated infections with methicillin-resistant Staphylococcus aureus (MRSA) contribute to significant hospitalization costs. We report here a droplet digital PCR (ddPCR) assay, which is a next-generation emulsion-based endpoint PCR assay for high-precision MRSA analysis. Reference cultures of MRSA, methicillin-susceptible S. aureus (MSSA), and confounders were included as controls. Copan swabs were used to sample cultures and collect specimens for analysis from patients at a large teaching hospital. Swab extraction and cell lysis were accomplished using magnetic-driven agitation of silica beads. Quantitative PCR (qPCR) (Roche Light Cycler 480) and ddPCR (Bio-Rad QX100 droplet digital PCR system) assays were used to detect genes for the staphylococcal protein SA0140 (SA) and the methicillin resistance (mecA) gene employing standard TaqMan chemistries. Both qPCR and ddPCR assays correctly identified culture controls for MRSA (76), MSSA (12), and confounder organisms (36) with 100% sensitivity and specificity. Analysis of the clinical samples (211 negative and 186 positive) collected during a study of MRSA nasal carriage allowed direct comparison of the qPCR and ddPCR assays to the Cepheid MRSA GeneXpert assay. A total of 397 clinical samples were examined in this study. Cepheid MRSA GeneXpert values were used to define negative and positive samples. Both the qPCR and ddPCR assays were in good agreement with the reference assay. The sensitivities for the qPCR and ddPCR assays were 96.8% (95% confidence interval [CI], 93.1 to 98.5%) and 96.8% (95% CI, 93.1 to 98.5%), respectively. Both the qPCR and ddPCR assays had specificities of 91.9% (95% CI, 87.5 to 94.9%) for qPCR and 91.0% (95% CI, 86.4 to 94.2%) for ddPCR technology.

Bacteria that masquerade as fungi: actinomycosis/nocardia.

The order Actinomycetales includes phylogenetically diverse but morphologically similar aerobic and anaerobic bacteria that exhibit filamentous branching structures which fragment into bacillary or coccoid forms. The aerobic actinomyces are a large, diverse group of gram-positive bacteria including Nocardia, Gordona, Tsukamurella, Streptomyces, Rhodococcus, Streptomycetes, Mycobacteria, and Corynebacteria. The anaerobic genera of medical importance include Actinomyces, Arachnia, Rothia, and Bifidobacterium. Both Actinomyces and Nocardia cause similar clinical syndromes involving the lung, bone and joint, soft tissue, and the central nervous system. The medically important Actinomyces organisms cause infections characterized by chronic progression, abscess formation with fistulous tracts and draining sinuses. Called "great masqueraders," diagnosis of actinomycosis and nocardiosis is often delayed. Once recognized, treatment of these infections requires long courses of parenteral and oral therapy. This review will compare and contrast infections due to Actinomyces and Nocardia.

Antibacterial activity of synthetic fire ant venom: the solenopsins and isosolenopsins.

BACKGROUND: We determined the in vitro activity of 9 synthetic fire ant venom alkaloids (+/-)-solenopsin A, (2R, 6R)-solenopsin A, (2S, 6S)-solenopsin B, (+/-)-isosolenopsin A, (2S, 6R)-isosolenopsin A,(2R, 6S)-isosolenopsin A, (+/-)-isosolenopsin B, (2S, 6R)-isosolenopsin B, and (2R, 6S)-isosolenopsin B against 6 species of bacteria (Streptococcus pneumoniae, Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Stenotrophomonas maltophilia, and Pseudomonas aeruginosa). METHODS: The minimum inhibitory concentration and minimum bacteriocidal concentration were determined in accordance with the Clinical Laboratory Standards Institute guidelines. Time kill studies used American Type Culture Collection bacterial isolates tested at 5 times the minimum inhibitory concentration. RESULTS: None of the venom alkaloids inhibited E. coli or P. aeruginosa, whereas all the alkaloids inhibited S. pneumoniae. Only 4 alkaloids inhibited S. pneumoniae, S. aureus, and S. maltophilia. Time-kill kinetics indicates that all 4 active alkaloids had bactericidal activity. CONCLUSIONS: Specific isomers of synthetic fire ant venom alkaloids have antibacterial activity against human pathogens.

In search of the holy grail of antifungal therapy.

The ideal antifungal agent remains an elusive goal for treatment of life-threatening systemic fungal infections. Such an agent would have broad antifungal activity, low rates of resistance, flexible routes of administration, few associated adverse events, and limited drug-drug interactions. Only three of the seven classes of antifungal agents currently available are suitable for treatment of systemic infection: the polyenes, the azoles, and the echinocandins. None match all the characteristics of an ideal agent, the Holy Grail of antifungal therapy. Academia and industry need to collaborate in the search for new lead antifungal compounds using traditional screening methods as well as the new pharmacogenomics methods. Enhancing efficacy and reducing toxicity of the currently available therapeutic agents is also another important avenue of study. As an example, the Mycosis Research Center at the University of Mississippi Medical Center has identified pyogenic polyenes in commercial preparations of amphotericin B deoxycholate which correlate with infusion related toxicities. A highly purified formulation of amphotericin B appears promising, with a better therapeutic index compared to its parent compound as evidenced by results of in vitro and in vivo studies reviewed in this presentation.

Antibiotic surveillance of Streptococcus pneumoniae in Mississipi.

OBJECTIVE: A survey of antimicrobial resistance in S. pneumoniae isolates collected from representative geographic regions of Mississippi during two different respiratory seasons was conducted to determine rates and distribution of drug resistance. DESIGN: A total of 318 S. pneumoniae isolates was collected from July 1999 to March 2000, and 171 isolates were collected from July 2001 to March 2002. The minimum inhibitory concentration for 12 antibiotics was determined by the micro dilution method. SETTING: A total of 28 hospitals through out the state of Mississippi participated in the submission of S. pneumoniae isolates felt to be clinically relevant and reported to the attending physician. Specimens were transported to a central laboratory via state health department courier. PATIENT POPULATION: Isolates were obtained from hospital inpatients as well as outpatients seen in local clinics. MAIN OUTCOME MEASURES: Changes in the percentage of isolates resistant to the tested antibiotics and patient demographics were collected. RESULTS: Pediatric isolates accounted for 36% and 28%, respectively, in 2000 and 2002. The relative percentage of total respiratory isolates remained for each year. Resistance to penicillin increased in pediatric (58% vs. 71%) and adult (40% vs. 52%) as did resistance to ceftriaxone (pediatric 14% vs. 31%; adult 9% vs. 25%) from 2000 to 2002. The majority of isolates were resistant to multiple antibiotics in both years tested. CONCLUSION: The results of this study are comparable to those from other national studies of antimicrobial resistance in S. pneumoniae demonstrating increasing resistance to multiple classes of antibiotics quantitatively and qualitatively.

Vancomycin-tolerance among clinical isolates of Streptococcus pneumoniae in Mississippi during 1999-2001.

BACKGROUND: In recent years, infection with Streptococcus pneumoniae has been a serious worldwide health concern. Antimicrobial-resistant S pneumoniae is increasing in incidence worldwide, posing a potentially serious threat. Resistance to beta-lactams, macrolides, and trimethoprim-sulfamethoxazole represents a major problem in the treatment of pneumococcal infections METHODS: Our laboratory conducted a survey of local resistance patterns in S pneumoniae. Clinical isolates from two separate respiratory seasons were collected from representative geographic areas in Mississippi (totaling 28 hospitals) and were tested for antimicrobial resistance to penicillin, amoxicillin, ceftriaxone, cefuroxime, azithromycin, clindamycin, tetracycline, trimethoprim-sulfamethoxazole, levofloxacin, gatifloxacin, moxifloxacin, and vancomycin using reference methods. Vancomycin-tolerant strains of S pneumoniae were initially identified as those in which the vancomycin MIC was 0.5 microg/mL. Strain tolerance was confirmed by time kill studies RESULTS: For the 1999-2000 respiratory season, 318 isolates were available for testing; for 2001-2002, 166 isolates were available. Of the 484 total isolates tested, two isolates were identified as having increased tolerance to vancomycin. A greater than 2 log10 difference in viability between the tolerant isolates and the nontolerant isolates of S pneumoniae was observed in time kill studies CONCLUSIONS: Two vancomycin-tolerant isolates of S pneumoniae were identified and characterized. Antibiotic tolerance is defined as the ability of bacteria to survive but not proliferate in the presence of an antibacterial agent. Tolerance to vancomycin is particularly significant when the incidence of penicillin tolerance or resistance is high. In addition, tolerance to vancomycin is not detected by routine in vitro susceptibility testing.

Differential expression of genes encoding immunomodulatory proteins in response to amphotericin B in human mononuclear cells identified by cDNA microarray analysis.

Amphotericin B (AMB) is an antifungal agent that possesses immunomodulatory properties that may contribute to its infusion-related toxicity and activity. It has previously been shown to induce the expression of genes encoding the cytokines interleukin (IL)-1 beta and tumour necrosis factor (TNF)-alpha and the chemokines IL-8 and macrophage inflammatory protein (MIP)-1 beta in the human monocytic cell line THP-1. In an effort to identify additional AMB-responsive genes, the gene expression profiles of both THP-1 cells and human peripheral blood mononuclear cells (hPBMCs) on exposure to AMB were assessed using cDNA microarray analysis. In addition to genes known to be AMB responsive, we found the genes encoding IL-1 alpha and MIP-1 alpha to be AMB responsive in both THP-1 cells and hPBMCs. Increases in MIP-1 alpha and MIP-1 beta were also observed in the supernatants of hPBMCs exposed to AMB. The expression of several genes in response to AMB was unique to either cell type. Furthermore, variability in gene expression in hPBMCs was observed between donors. These genes and respective gene products may have significance in the infusion-related toxicity and activity of AMB.