Comparison of two methods for assessing the removal of total organisms and pathogens from the skin.
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A standard hand-wash sampling technique was compared with a simple finger-streak sampling method in assessing the relative effectiveness of a number of alternative preparations used for disinfecting the surgeon's hands (alcoholic 0.5% chlorhexidine, alcoholic 0.1% tetrabrom-o-methyl phenol, a 4% chlorhexidine detergent solution, aqueous 0.5% chlorhexidine, 2% 'Irgasan' detergent solution and, as control, bar soap). There was a fairly good correlation between the results of assessment by the two methods after a single disinfection and after six disinfections, three on one day and three on the next. Significant differences were shown in 21 comparisons between treatments when the hand-wash sampling test was used, and 16 of these comparisons also showed a significant difference by the finger-streak test. Staphylococcus aureus was found in hand samplings from 5 out of 8 nurses in the Burns Unit of Birmingham Accident Hospital by the hand-wash sampling method and from 2 of the same 8 nurses by the finger-streak method; the numbers were small, and no Staph. aureus were isolated from the same hands after 1 min. wash in 70% ethyl alcohol. Similar sampling on 29 nurses in other wards showed Staph. aureus on 3 nurses (one in large numbers) by the hand-wash technique and on 1 nurse by the finger-streak test; in only 1 nurse whose hands showed Staph. aureus before disinfection was the organism found, by hand-wash sampling, after disinfection. Parallel sampling of nurses' hands after washing with soap and water and after disinfection with 95% ethanol showed larger numbers of Staph. aureus in a hospital for skin diseases than in a general hospital, and a lower incidence and somewhat lower density of Staph. aureus after ethanol treatment than after washing with soap and water; Gram-negative bacilli, on the other hand, were commoner on hands in the general than in the skin hospital, and present in much smaller numbers after disinfection with ethanol than after washing with soap and water. Antibiotic sensitivity tests showed the frequent recurrence on the hands of some nurses of multi-resistant Staph. aureus with resistance patterns similar to those found in infective lesions in some of the patients; different sensitivity patterns were usually found in staphylococci isolated from the nose. Even in wards where many patients were infected, carriage by nurses' hands of a particular strain of Staph. aureus did not seem to last for more than a few days. (+info)
Characterization of Cryptosporidium parvum by matrix-assisted laser desorption ionization-time of flight mass spectrometry.
(34/846)
Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) was used to investigate whole and freeze-thawed Cryptosporidium parvum oocysts. Whole oocysts revealed some mass spectral features. Reproducible patterns of spectral markers and increased sensitivity were obtained after the oocysts were lysed with a freeze-thaw procedure. Spectral-marker patterns for C. parvum were distinguishable from those obtained for Cryptosporidium muris. One spectral marker appears specific for the genus, while others appear specific at the species level. Three different C. parvum lots were investigated, and similar spectral markers were observed in each. Disinfection of the oocysts reduced and/or eliminated the patterns of spectral markers. (+info)
Outbreak of Bacillus cereus infections in a neonatal intensive care unit traced to balloons used in manual ventilation.
(35/846)
In 1998, an outbreak of systemic infections caused by Bacillus cereus occurred in the Neonatal Intensive Care Unit of the University Hospital Vrije Universiteit, Amsterdam, The Netherlands. Three neonates developed sepsis with positive blood cultures. One neonate died, and the other two neonates recovered. An environmental survey, a prospective surveillance study of neonates, and a case control study were performed, in combination with molecular typing, in order to identify potential sources and transmission routes of infection. Genotypic fingerprinting by amplified-fragment length polymorphism (AFLP) showed that the three infections were caused by a single clonal type of B. cereus. The same strain was found in trachea aspirate specimens of 35 other neonates. The case control study showed mechanical ventilation with a Sensormedics ventilation machine to be a risk factor for colonization and/or infection (odds ratio, 9.8; 95% confidence interval, 1.1 to 88.2). Prospective surveillance showed that colonization with B. cereus occurred exclusively in the respiratory tract of mechanically ventilated neonates. The epidemic strain of B. cereus was found on the hands of nursing staff and in balloons used for manual ventilation. Sterilization of these balloons ended the outbreak. We conclude that B. cereus can cause outbreaks of severe opportunistic infection in neonates. Typing by AFLP proved very useful in the identification of the outbreak and in the analysis of strains recovered from the environment to trace the cause of the epidemic. (+info)
Comparison of iodophor and alcohol pledgets with the Medi-Flex blood culture prep kit II for preventing contamination of blood cultures.
(36/846)
Iodophor and alcohol pledgets were compared with the Medi-Flex Prep Kit II for skin disinfection before venipuncture. Of 12,367 blood cultures collected, 6,362 were done with conventional pledgets and 6, 005 were done with Medi-Flex kits. Contamination occurred in 351 of 6,362 blood cultures (5.5%; range, 3.7 to 8.1%) with conventional pledgets versus 328 of 6,005 (5.5%; range, 3.5 to 7.5%) with Medi-Flex kits. (+info)
Comparative investigations of Listeria monocytogenes isolated from a turkey processing plant, turkey products, and from human cases of listeriosis in Denmark.
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Listeria monocytogenes was isolated from critical control points in a Danish turkey processing plant, from turkey products and from cases of human listeriosis. During processing in the plant the prevalence of L. monocytogenes ranged from 25.9 to 41.4%. Cleaning and disinfection decreased the prevalence to 6.4%. Isolates of L. monocytogenes were characterized by pulsed-field gel electrophoresis (PFGE) using restriction endonuclease ApaI. Identical DNA types were obtained from turkey products and the processing line even after cleaning and disinfection. Two identical DNA types were demonstrated among isolates from turkey products and human cases of listeriosis. The prevalence of L. monocytogenes in turkey products ranged from 7.3 to 17.4% for ready-to-eat products and raw products, respectively. Since none of the 27 flocks examined before slaughter sampled positive for L. monocytogenes and the prevalence increased during processing, the potential risk from turkey meat was apparently due to factory hygiene rather than intrinsic contamination of the turkeys. (+info)
Protocol for detection of biofilms on needleless connectors attached to central venous catheters.
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Central venous catheter needleless connectors (NCs) have been shown to develop microbial contamination. A protocol was developed for the collection, processing, and examination of NCs to detect and measure biofilms on these devices. Sixty-three percent of 24 NCs collected from a bone marrow transplant center contained biofilms comprised primarily of coagulase-negative staphylococci. (+info)
A comparison of cyst age and assay method of the efficacy of contact lens disinfectants against Acanthamoeba.
(39/846)
AIMS: (i) To determine effect of Acanthamoeba cyst age, method of production, and (ii) to assay technique on the efficacy of multipurpose solutions (MPS) and hydrogen peroxide based contact lens disinfectants. (iii) To establish if MPS can remove mature cysts from contact lenses according to the ISO/DIS 14729 regimen test for microbe removal. METHODS: Immature and mature cysts of A polyphaga were tested against the MPS Opti-Free express and the hydrogen peroxide based solutions Oxysept 1Step and Oxysept 1 using two assay methods. Simulated patient regimen testing was performed with the Opti-Free express and Complete using mature cysts inoculated on to group I or group IV lenses. RESULTS: Immature cysts were sensitive to disinfection by all solutions. No killing was observed with mature cysts with Opti-Free express, while immature cysts yielded a 1-2 log reduction in viability. Oxysept 1Step gave a 1.1 (SD 0.3) log reduction in mature cysts after 6 hours. Oxysept 1 gave a 2.4 (0.3) log reduction in mature cysts after 4 hours and a 3.8 (0.5) log reduction after 6 hours. Patient regimen testing using Opti-Free express and Complete resulted in no recovery of viable mature cysts from the contact lenses or from the soaking solutions. CONCLUSION: Cyst age but not method of production used in this study influences the efficacy of contact lens disinfectants against Acanthamoeba. MPS are effective in removing cysts from contact lens surfaces and may have a role in the prevention of acanthamoeba keratitis. (+info)
Oligophilic bacteria as tools to monitor aseptic pharmaceutical production units.
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The bacterial loads of air, surfaces, and personnel in clean rooms are routinely monitored using a set of standard media. Bacteria that can grow on these media are a tiny fraction of the total numbers in any environment. A substantial proportion of bacteria long thought to be unculturable were recently shown to be oligophilic. Oligophile counts in clean rooms in our studies exceeded the standard plate counts by up to 2 orders of magnitude. They responded to disinfection routines in ways similar to the responses of conventional bacteria. We suggest that oligophiles are better tools than conventional bacteria for environmental monitoring in aseptic pharmaceutical production units. (+info)