Interim analysis of a 3-year follow-up study of NS5A and NS3 resistance-associated substitutions after treatment with grazoprevir-containing regimens in participants with chronic HCV infection.

BACKGROUND: In HCV-infected people who fail to achieve sustained virological response after receiving a direct-acting antiviral regimen, virological failure is almost always accompanied by the presence of resistance-associated substitutions (RASs) in the target protein(s). The aim of this long-term observational study was to evaluate the persistence of NS3/4A and NS5A RASs in participants with genotype (GT) 1 infection who relapsed following treatment with a grazoprevir-containing treatment regimen. METHODS: RASs were evaluated at baseline (that is, pre-dose on day 1 of the original treatment), at the time of virological failure, and up to follow-up week 96. A total of 58 participants were included. RESULTS: In participants treated with elbasvir/grazoprevir ± ribavirin, observed baseline NS3 RASs included 56F, 80K/L, 122N and 170V/I, and observed treatment-emergent NS3 RASs included 36M, 56F/H, 122G, 132I, 156G/I/L/P/T, 168A/E/G/V/Y and 170T. Observed baseline NS5A RASs included 28M/T/V, 30H/R, 31M/V and 93H/N, and treatment-emergent NS5A RASs included 28A/G/S/T, 30H/R, 31M/V and 93H/N/S. Baseline NS3 and NS5A RASs present at time of failure tended to persist during follow-up, and most were detectable for more than 2 years following virological failure. Treatment-emergent NS5A RASs present at time of failure also tended to persist for more than 2 years following virological failure (93%). By contrast, >80% of treatment-emergent NS3 RASs detected at failure had been supplanted by wild type by week 36. CONCLUSIONS: Treatment-emergent NS5A RASs can persist for extended periods of time. Retreatment strategies should take account of the presence of these RASs.

Central venous catheter-related blood stream infections in children undergoing hematopoietic stem cell transplant for primary immunodeficiency and other nonmalignant disorders.

A single-center experience of catheter-related blood stream infections in children undergoing hematopoietic stem cell transplant for primary immunodeficiency is described. The rate of definite central venous catheter infections was 5.31/1000 line days. Staphylococcus epidermidis was the most commonly identified organism. Teicoplanin resistance occurred in 17% of S. epidermidis infections. The central catheter was removed in 21% of infections.

A novel chromogenic medium for isolation of Pseudomonas aeruginosa from the sputa of cystic fibrosis patients.

BACKGROUND: A novel chromogenic medium for isolation and identification of Pseudomonas aeruginosa from sputa of cystic fibrosis (CF) patients was evaluated and compared with standard laboratory methods. METHODS: One hundred sputum samples from distinct CF patients were cultured onto blood agar (BA), Pseudomonas CN selective agar (CN) and a Pseudomonas chromogenic medium (PS-ID). All Gram-negative morphological variants from each medium were subjected to antimicrobial susceptibility testing, and identification using a combination of biochemical and molecular methods. RESULTS: P. aeruginosa was isolated from 62 samples after 72 h incubation. Blood agar recovered P. aeruginosa from 56 samples (90.3%) compared with 59 samples (95.2%) using either CN or PS-ID. The positive predictive value of PS-ID (98.3%) was significantly higher than growth on CN (88.5%) for identification of P. aeruginosa (P<0.05). CONCLUSIONS: PS-ID is a promising medium allowing for the isolation and simultaneous identification of P. aeruginosa from sputa of CF patients.

Contamination of the hospital environment with gastroenteric viruses: comparison of two pediatric wards over a winter season.

The aims of this study were to examine the extent of gastroenteric virus contamination in a pediatric primary immunodeficiency (PPI) ward and a general pediatric ward over a winter season and to determine whether changes to hospital infection control interventions would have an impact on environmental contamination levels within pediatric units. Environmental swabs were collected weekly from 11 sites in both wards from 15 December 2005 to 3 March 2006 and examined for the presence of norovirus (NoV), astrovirus, and rotavirus (RV) by reverse transcriptase PCR. Viruses were detected in 17% and 19% of swabs from both wards. Virus contamination for NoV and RV decreased from 20% to 6% and 15% to 10% of swabs, respectively, in the PPI ward from the 2004 study by Gallimore et al. (C. I. Gallimore, C. Taylor, A. R. Gennery, A. J. Cant, A. Galloway, M. Iturriza-Gomara, and J. J. Gray, J. Clin. Microbiol. 44:395-399, 2006). Overall, changes to cleaning protocols were deemed to have reduced the level of environmental contamination with gastroenteric viruses, but contamination still occurred due to a breakdown in infection control procedures indicated by contamination in areas frequented by parents but used only occasionally by staff.

Comparison of BD GeneOhm real-time polymerase chain reaction with chromogenic and conventional culture methods for detection of group B Streptococcus in clinical samples.

A total of 200 antenatal high vaginal swabs were screened for the presence of group B Streptococcus (GBS) using a conventional culture method (recommended by Centers for Disease Control and Prevention). Screening was also performed by using a new chromogenic agar, chromID Strepto B, and by using the BD GeneOhm StrepB real-time polymerase chain reaction (PCR), which was performed directly on swabs without enrichment. Using a combination of all methods, we detected GBS in 101 samples. A total of 82 samples (81.2%) were positive using PCR, and 83 samples (82.2%) were confirmed as positive by culture (any method). PCR was more sensitive for detection of GBS than direct culture using any method (P < 0.0005). PCR was also more sensitive than any single enrichment method, but this difference was not statistically significant. With culture as a "gold standard", the PCR method showed a sensitivity of 77.1% and a positive predictive value of 79.3%. Of the culture-positive samples, significantly, more GBSs were detected by direct plating on chromID Strepto B than on selective sheep blood agar (67.5% versus 57% respectively, P < 0.02). After selective enrichment, 92.8% of GBS were isolated on chromID Strepto B compared with 89.2% isolated on sheep blood agar.

Recovery of antimicrobial-resistant Pseudomonas aeruginosa from sputa of cystic fibrosis patients by culture on selective media.

OBJECTIVES: To assess the utility of direct plating of whole sputa onto selective media as a means of identifying antimicrobial resistance in strains of Pseudomonas aeruginosa from the sputa of patients with cystic fibrosis (CF). METHODS: A total of 45 sputum samples from CF patients were cultured onto conventional culture media for isolation of P. aeruginosa and were also cultured directly onto Iso-Sensitest agar plates containing each of 10 antimicrobials incorporated at a 'breakpoint' concentration. A representative of each colonial type (morphotype) recovered from both routine media and selective media was tested for its susceptibility to 10 antimicrobials using a standard agar dilution MIC technique. RESULTS: Of the samples shown to contain resistant strains, the proportion (%) detected using routine media and selective media, respectively, was: 42 and 100 for amikacin, 57 and 100 for gentamicin, 54 and 100 for tobramycin, 88 and 77 for aztreonam, 62 and 90 for ceftazidime, 70 and 97 for meropenem, 61 and 100 for piperacillin/tazobactam, 90 and 86 for temocillin, 66 and 100 for ticarcillin/clavulanic acid, and 80 and 90 for ciprofloxacin resistance. The increased rates of isolation on selective media were statistically significant (P < 0.05) for amikacin, gentamicin, tobramycin, meropenem, piperacillin/tazobactam and ticarcillin/clavulanic acid. CONCLUSIONS: For most antimicrobials, selection of colonies from conventional media for antimicrobial susceptibility testing provided a considerable underestimation of resistance in P. aeruginosa. The use of selective media for the culture of whole sputum was effective for the detection of resistant isolates of P. aeruginosa.

Environmental monitoring for gastroenteric viruses in a pediatric primary immunodeficiency unit.

The aim of this study was to determine if gastroenteric viruses were present on surfaces and equipment in a pediatric primary immunodeficiency unit (PPIU) by environmental sampling using swabs and subsequent nucleic acid extraction and reverse transcriptase PCR assays. A PPIU was chosen, and 11 swabs were taken at the same sites every 2 weeks for 6 months. Nested/heminested PCR assays were used to screen for astroviruses (AsV), noroviruses (NoV), and rotaviruses (RV). AsV, NoV, and RV were detected at multiple swab sites during the study period. NoV was the most frequently detected virus on environmental surfaces; however, RV was detected on 79% and NoV on 50% of swabbing dates during the study period. Toilet taps were the most contaminated sites. Fecal samples from selected patients in the unit were also screened during the study period, and patients excreted AsV, NoV, and RV at times during the study. New cleaning schedules and changes in some of the PPIU sanitary furniture have been suggested as a means of reducing environmental contamination.

Use of a heminested reverse transcriptase PCR assay for detection of astrovirus in environmental swabs from an outbreak of gastroenteritis in a pediatric primary immunodeficiency unit.

An outbreak of astrovirus gastroenteritis occurred in the Primary Immunodeficiency Unit at Newcastle General Hospital in March 2004. Environmental swabbing of the unit was undertaken after the outbreak, with multiple sites swabbed pre- and postcleaning. Astroviruses were detected in four environmental swabs and from two patient fecal samples using heminested reverse transcriptase PCR. An astrovirus genotype 3 strain was identified in both environmental swabs and fecal specimens and was the strain identified as being responsible for the outbreak. Environmental transmission of the virus was thought to have occurred by contamination of a syringe pump outside the laminar-flow curtain of a patient who was admitted with astrovirus gastroenteritis. This was subsequently transmitted to a cubicle next door and to a television/games console in a parents' room in the ward. Environmental monitoring of surfaces/equipment, using PCR assays for gastroenteric viruses in hospital situations where infection can give rise to serious clinical complications, may have a role in controlling and monitoring cleaning and the subsequent prevention of nosocomial transmission of gastroenteritis.

Detection of pneumolysin in sputum.

Western blot detection of the species-specific pneumococcal product, pneumolysin (SPN), was shown to be almost as sensitive as PCR for the non-cultural detection of pneumococci in 27 Streptococcus pneumoniae culture-positive sputa from patients stated to have chest infections. Both techniques were considerably more sensitive than counter-current immuno-electrophoresis for pneumococcal capsular polysaccharide antigens (CPS-CIE) on the same specimens. Sensitivities for PCR, SPN-immunoblotting and CPS-CIE were 100%, 85% and 67%, respectively. In 11 S. pneumoniae culture-negative sputa taken from patients receiving antibiotics, but with proven recent pneumococcal infection, PCR and SPN-blot were positive in six (in two of which CPS-CIE was also positive), PCR alone was positive in one and SPN-blot alone was positive in one. In 11 S. pneumoniae culture-negative samples from patients not receiving antibiotics, all three tests were negative in eight, PCR was positive in three (in one of which CPS-CIE was also positive), but SPN-blot was negative in all 11. In 16 S. pneumoniae culture-negative samples from patients receiving antibiotics and with no known recent pneumococcal infections, one or more non-cultural test was positive in 11. Although further evaluation is required to assess the significance of pneumolysin detection in relation to carriage and infection and to devise a more suitable test format, these preliminary studies suggest that pneumolysin detection is a promising new approach to the non-cultural diagnosis of pneumococcal chest infection.