Prevalence of Listeria monocytogenes in ready-to-eat foods sampled from the point of sale in Wales, United Kingdom.

A survey of Listeria in ready-to-eat food took place in Wales, United Kingdom, between February 2008 and January 2009. In total, 5,840 samples were taken and examined for the presence of Listeria species, including L. monocytogenes. Samples were tested using detection and enumeration methods, and the results were compared with current United Kingdom guidelines for the microbiological quality of ready-to-eat foods. The majority of samples were negative for Listeria by both direct plating and enriched culture. Seventeen samples (0.29%) had countable levels of Listeria species (other than L. monocytogenes), and another 11 samples (0.19%) had countable levels of L. monocytogenes. Nine samples (0.15%) were unsatisfactory or potentially hazardous when compared with United Kingdom guideline limits; six (0.10%) were in the unsatisfactory category (>100 CFU/g) for Listeria species (other than L. monocytogenes), and three (0.05%) were in the unacceptable or potentially hazardous category (>100 CFU/g) for L. monocytogenes. All three of these samples were from sandwiches (two chicken sandwiches and one ham-and-cheese sandwich). The most commonly isolated serotype of L. monocytogenes was 1/2a. This survey was used to determine the current prevalence of Listeria species and L. monocytogenes in ready-to-eat foods sampled from the point of sale in Wales.

Continuous non-seasonal epidemic of respiratory syncytial virus infection in the southeast United States.

BACKGROUND: This study was done to define the seasonality of respiratory syncytial virus (RSV) epidemics in the southeastern United States. METHODS: We tested 5,092 fresh nasal aspirates or washings, using the Kallestad Pathfinder enzyme immunoassay (EIA) or the Directigen RSV membrane EIA according to manufacturers' directions. RESULTS: A total of 1,419 (27.9%) respiratory specimens, collected from pediatric patients between May 1993 and December 1996 at two large southeastern medical centers, were positive for RSV antigen by enzyme immunoassay. A persistent RSV epidemic was documented between July 1993 and December 1996. We defined an epidemic as 2 consecutive months in each of which > or = 10% of the specimens were positive and > or = 2 positive specimens detected. The highest percentages of positive specimens were detected in December of 1993, 1994, and 1996, to date, and November 1995. CONCLUSION: On the basis of our findings, we recommend health care workers consider RSV in the differential diagnosis of acute respiratory illness throughout the year in pediatric patients from the southeast United States.

Four-day incubation period for blood culture bottles processed with the Difco ESP blood culture system.

Blood culture records from 1994 to 1995 from five U.S. medical centers all using the Difco ESP continuous monitoring blood culture system were reviewed retrospectively. Among a total of 7,362 isolates of bacteria and yeasts, only 0.1% of possibly significant isolates would have been missed had blood cultures been routinely incubated for 4 days instead of the 5 days recommended by the manufacturer. Conversely, numerous contaminants, detected only on day 5, would have been eliminated by a 4-day incubation period.

Evaluation of two commercially available DNA tests for detection of human papillomavirus.

OBJECTIVE: This study was designed to compare the sensitivity, specificity, efficiency, positive and negative predictive values, and ease of use for 2 commercially available hybridization kits for detecting human papillomavirus (HPV) DNA: Oncor Southern blot (SB) (Oncor, Inc., Gaithersburg, MD) and Digene ViraType dot blot (DB) (Digene Diagnostics, Inc., Silver Spring, MD). METHODS: A total of 179 specimens (172 cervical and 7 penile biopsies) were assessed for acceptability based on the presence of epithelial cells and tested for HPV by DB and SB. The results were evaluated based on Papanicolaou-stained cervical specimens and selected risk factors. RESULTS: One hundred six (97.2%) of 109 results were concordant, i.e., 93 negative (85.3%) and 13 positive (11.9%). Using SB as the gold standard, we found the sensitivity, specificity, efficiency, and positive and negative predictive values for the ViraType DB to be 100%, 96.9%, 97.3%, 81.3%, and 100%, respectively. Comparing the Papanicolaou smear to SB and DB, we found the sensitivity, specificity, efficiency, and positive and negative predictive values to be 33.3% (SB) vs. 44.4% (DB), 89.5% vs. 87.6%, 87.3% vs. 84.2%, 11.8% vs. 23.5%, and 97.0% vs. 94.9%, respectively. The only significant risk factor for predicting an HPV infection was the number of sexual partners. CONCLUSIONS: Although SB has been considered the standard model, DB is an acceptable method for detecting and identifying HPV infections.

Nosocomial herpes simplex virus infection associated with oral endotracheal intubation.

BACKGROUND: To determine by culture the frequency of herpes simplex virus reactivation complicating oral endotracheal intubation. Additionally, clinical appearance and recognition of patient infection by attendant health care workers were studied. Last, evidence of any occupational acquisition of herpes simplex virus infection was sought. METHODS: In a prospective, non-randomized study, three serial viral cultures were taken of oro-facial or mucosal sites on the day of oral endotracheal intubation and in the subsequent 3rd and 5th or 7th days from 51 consecutive adults undergoing oral endotracheal intubation in a suburban community hospital. Clinical variables including appearances of lesions and therapeutic interventions were noted during serial assessments by study authors. Employee health records were reviewed for evidence of health care worker occupational herpes simplex virus infection associated with these cases. RESULTS: Of 51 patients, 4 were culture positive on the day of oral endotracheal intubation. Of the remaining 47 patients, serial cultures during the first week post intubation revealed herpes simplex virus in 25 (53.2%) patients. Of cohort variables studied, a history of prior oral herpes simplex virus was significantly associated with a subsequent positive viral culture for herpes simplex virus (relative risk, 2.29; 95% confidence interval, 1.48 to 3.56). Typical or atypical lesions were visible in only 52% of the herpes simplex virus culture-positive cases. No occupational transmission of herpes simplex virus was detected. Tape-securing practices appeared to contribute to the morbidity of herpes simplex virus eruptions. CONCLUSIONS: Nosocomial reactivation of herpes simplex virus infection complicated oral endotracheal intubation in our patient population in approximately one half of the patients who were intubated for more than 48 hours during the first week after the procedure. Clinically, the infection was recognizable in only one half of the virus culture-positive cases. Increased awareness of this infection is needed by health care workers, patients, and families. More information is needed on optimal therapy and prevention.

Evaluation of five methods for respiratory syncytial virus detection.

A total of 117 nasal aspirates were cultured for respiratory syncytial virus (RSV) and tested for RSV antigen by a direct fluorescent-antibody (DFA) test (Bartels Immunodiagnostic Supplies, Inc., Bellevue, Wash.), the Directigen enzyme immunoassay (EIA; Becton Dickinson Microbiology Systems, Cockeysville, Md.), the TestPack EIA (Abbott Laboratories, North Chicago, Ill.), and RSV EIA (Abbott). Agreement of two of five methods or a positive RSV culture were required to validate a result. A total of 57 of 117 (48.7%) specimens were culture positive in HEp-2 cells, A549 cells, or both. A total of 5 of 117 (4.3%) additional specimens met the criteria of a positive specimen; i.e., 62 of 117 (53.0%) specimens were positive. Results obtained from 77 of 117 (65.8%) specimens were concordant for all five methods. The sensitivities, specificities, and positive and negative predictive values for the culture and DFA methods were 91.9, 100, 100, and 91.7% and 91.9, 96.4, 96.6, and 91.4%, respectively. The sensitivities, specificities, and positive and negative predictive values for the three EIA procedures, Directigen, TestPack, and RSV EIA, were 75.8, 80.0, 81.0, and 74.6%; 93.6, 100, 100, and 93.2%; and 71.0, 100, 100, and 75.3%, respectively. New self-contained EIA configurations and the DFA method offer attractive alternatives to the culture method. Technical simplicity, rapid turnaround time, performance, and cost must all be considered when selecting a system for RSV detection.

In vitro bactericidal activities of gentamicin, cefazolin, and imipenem in peritoneal dialysis fluids.

Continuous ambulatory peritoneal dialysis is an important modality of therapy for patients with renal disease. However, peritonitis continues to be a major risk factor and is usually treated by intraperitoneal administration of antimicrobial agents. Few data are available concerning the stability of antimicrobial agents in peritoneal dialysis solution beyond 48 h. Our investigation was designed to establish the chemical and biological stability of gentamicin alone and in combination with cefazolin in peritoneal dialysis solution at 6 and 72 h by an immunoassay and by an in vitro bactericidal test against American Type Culture Collection (Rockville, Md.) strains of Pseudomonas aeruginosa, Staphylococcus aureus, and Staphylococcus epidermidis. In addition, uninfected peritoneal dialysis effluent was inoculated with three American Type Culture Collection strains and gentamicin or imipenem. Gentamicin alone or in combination with cefazolin was not altered chemically and was bactericidal for Staphylococcus spp. but not P. aeruginosa. In contrast, imipenem was active against both Staphylococcus spp. and P. aeruginosa. Undefined factors other than inactivation of gentamicin may be responsible for the lack of bactericidal activity and treatment failure of Pseudomonas infections.

Evaluation of a rapid latex slide agglutination test for herpes simplex virus as a specimen screen and culture identification method.

A total of 449 clinical specimens and 199 culture fluids were tested using the Virogen Herpes Slide Test (Wampole Laboratories, Div. Carter-Wallace, Inc., Cranbury, N.J.), a rapid latex agglutination procedure. The results were compared with those obtained with isolation of herpes simplex virus in cell culture followed by identification using immunoperoxidase or fluorescent reagents. The sensitivity, specificity, and positive and negative predictive values of the direct test were 49.7, 93.4, 96.0, and 37.1%, respectively. The sensitivity and specificity of the latex agglutination test for culture confirmation were 75.9 and 100%, respectively.

Comparison of the Ortho Cultureset (Vero cells) and Difco Cellmatics system (mink lung and primary rabbit kidney cells) for the detection of herpes simplex virus from clinical specimens.

Two Cellmatics (Difco) Herpes simplex virus (HSV) detection systems, one with mink lung cells (ML) and the other with primary rabbit kidney cells (PRK) and the Cultureset (Ortho) system with Vero cells were compared for their ability to detect previously positive specimens. One hundred fifty patients specimens positive for HSV in either Vero or PRK cells prior to freezing at -70 degrees C were thawed once, diluted to 1:8, and inoculated in duplicate into each cell system. Positive cultures were detected using each kit's immunoperoxidase method. All three cell lines were stained at 24 hr followed by a final staining of negative cultures at 48 hr for Cultureset and at 72 hr for Cellmatics as per kit instructions. At 24 hr percent detection was: Cellmatics (ML) = 85%, Cellmatics (PRK) = 81%, Cultureset (Vero) = 74%. At final staining percent detection was 94%, 92%, and 84%, respectively. The Cellmatics system has the advantage of fewer steps in the staining procedure and no manipulation of coverslips because staining is performed in the tubes. As employed in these commercial systems, the Cellmatics system with ML cells is more sensitive than the Cultureset with Vero cells (p less than 0.001) and comparable to the Cellmatics system with PRK.

Premarket evaluation of IDS RapID SS/u system for identification of urine isolates.

A total of 170 fresh clinical urine isolates were tested with a premarket configuration of the RapID SS/u system (Innovative Diagnostic Systems, Inc., Atlanta, Ga.), a qualitative micromethod for the identification of selected organisms commonly isolated from urine specimens. Results were compared with those obtained with conventional methods of identifying gram-positive isolates and with the AutoMicrobic system (Vitek Systems, Inc., Hazelwood, Mo.), utilizing Gram-Negative Identification cards for the identification of gram-negative rods. Organisms representing 12 taxa were included in the study. Of the 170 isolates, 163 (95.9%) were correctly identified. A total of 144 strains (84.7%) were correctly identified without additional testing, whereas 19 isolates (11.2%) required further testing. Seven isolates (4.1%) were incorrectly identified. The SS/u system required minimal hands-on time inoculate and interpret reactions. Discrepancies most often occurred with regard to misinterpretation of Escherichia coli and Enterobacter sp. as Citrobacter sp. The IDS RapID SS/u system may indeed prove valuable for the rapid manual identification of urine isolates.

Comparison of a latex agglutination test with five other methods for determining the presence of antibody against cytomegalovirus.

A latex agglutination test for determination of antibody against cytomegalovirus was compared with five other methods: a solid-phase fluorescent immunoassay, an indirect hemagglutination test, two solid-phase enzyme immunoassays, and an indirect fluorescent-antibody method, with sera collected from 210 random blood donors. Of the sera tested, 28% were positive for anti-cytomegalovirus by concordance of four or more methods. The latex agglutination test performed well, with a sensitivity of 100%, a specificity of 99%, and positive and negative predictive values of 97 and 100%, respectively. The methods were also evaluated for the number of sera requiring repeat testing, equivocal results after retesting, ease of performance, turnaround time, and technical demands. The tests which best met the requirements for a screening test were the solid-phase fluorescent immunoassay, the indirect hemagglutination test, and the latex agglutination test. The latex agglutination test is a valuable screening tool for detecting total anti-cytomegalovirus which has high sensitivity, high negative predictive value, and rare equivocal results and also has the added advantages of ease of performance and rapid turnaround time.

Setiferous structures of male coleoptera.

A scanning electron microscopy study was made of the male setiferous sex patches and analogous structures in 11 families of Coleoptera (Anthribidae, Bruchidae, Ciidae, Cleridae, Coccinellidae, Dermestidae, Leiodidae, Ptinidae, Staphylinidae, Tenebrionidae, and Ostomatidae). These secondary sexual characters appear to have several features in common including relatively long, often ridged, setae, cuticular ducts (frequently cribriform pore plates), and the production of a secretion. It is suggested that these structures may all be concerned with the production, release, and dissemination of pheromones.