Opportunistic Aspergillus pathogens measured in home and hospital tap water by quantitative PCR (QPCR).

Opportunistic fungal pathogens are a concern because of the increasing number of immunocompromised patients. The goal of this research was to test a simple extraction method and rapid quantitative PCR (QPCR) measurement of the occurrence of potential pathogens, Aspergillus fumigatus, A. flavus, A. terreus and A. niger, in home tap water and a hospital water supply. Water samples were taken from the kitchen tap in the homes of 60 patients who were diagnosed with legionellosis. Water samples were also taken from three locations in a hospital that generated all of its hot water by flash heating. Opportunistic infectious agents Aspergillus fumigatus, A. flavus, A. terreus and A. niger were measured using QPCR. Aspergillus terreus DNA was found in 16.7% and A. fumigatus DNA in 1.7% of the samples taken from the kitchen tap. None of the Aspergillus species were found in any of the hospital water samples.The development of a simple DNA extraction method along with QPCR analysis is suitable for rapid screening of tap water for opportunistic fungal pathogens. This simple method can be used to obtain pathogen occurrence results in about 3 h, instead of waiting days to weeks for culture data. Obtaining pathogen occurrence data in a timely manner could promote the elimination of the pathogens from the water supply of immunocompromised patients.

Monitoring Aspergillus species by quantitative PCR during construction of a multi-storey hospital building.

During the enlargement of an existing hospital, quantitative polymerase chain reaction (PCR) was used to monitor Aspergillus spp. populations within the construction site. The rapid availability of results meant that the construction schedule was largely uninterrupted, while assuring that the new construction was free from contamination by the targeted Aspergillus spp.

Survival of some medically important fungi on hospital fabrics and plastics.

Tests of the survival of Candida spp., Aspergillus spp., a Fusarium sp., a Mucor sp., and a Paecilomyces sp. on hospital fabrics and plastics indicated that viability was variable, with most fungi surviving at least 1 day but many living for weeks. These findings reinforce the need for appropriate disinfection and conscientious contact control precautions.

PcrV immunization enhances survival of burned Pseudomonas aeruginosa-infected mice.

Burned Pseudomonas aeruginosa-infected mice immunized against PcrV, a type III virulence system translocating protein, showed significantly enhanced survival compared to controls. Survival was non-O serotype specific and correlated with a reduced systemic microbial load. Infection with a high-level toxin A-producing strain required supplemental antitoxin treatment to enhance survival.

Does the addition of nystatin to 5% mafenide acetate and genitourinary irrigant solutions interfere with their antimicrobial activity? Assessment by two topical antimicrobial test assay systems.

Results previously reported using the Wet Disc Topical Antimicrobial Assay (WDA) suggested that adding nystatin (NY) to a 0.5% mafenide acetate (MA) suspension or genitourinary irrigant (double antibiotic [DAB]) to expand their antimicrobial activity to include Candida sp. antagonized the antibacterial effect of MA but not DAB. We use DAB solution as described by the authors of the previous study, also, but we use a 5% commercially available mafenide acetate solution instead of the in-house prepared 0.5% mafenide acetate suspension that they used. Further, we use both the WDA and the Agar Well Diffusion Topical Antimicrobial Assay (AWDA) to test topical antimicrobials at this institution. In light of the previously reported results, this study 1) examined whether adding nystatin to DAB or the 5% mafenide acetate solution used at this institution caused any interference in the ability of these substances to migrate through the agar matrices and cause zones of growth inhibition in the two test assay systems and 2) compared the assessment of microbial susceptibility (by very precise definition) between the two systems. The addition of nystatin did not interfere with the ability of either DAB or mafenide acetate to migrate through the agar matrices and cause clear zones. However, on the assessment of susceptibility a significantly larger number of organisms were judged susceptible using the AWDA than the WDA. We believe that the disparity is caused by a large difference in agar diffusion kinetics between the two assays. Therefore, we recommend the AWDA rather than the WDA for susceptibility studies.

Gelatinase activities in wounds of healing-impaired mice versus wounds of non-healing-impaired mice.

The gelatinases, matrix metalloproteinase-2 and -9 (MMP-2 and MMP-9), have been implicated in different aspects of wound repair. However, little is known about MMP-2 and MMP-9 activity in animal models of impaired wound healing. We sought to compare serial gelatinase activities for 25 days after full-thickness excisional wounds in genetically diabetic healing-impaired mice and their nondiabetic non-healing-impaired littermates. Wound samples were frozen, homogenized, clarified by centrifugation, and analyzed on zymography gels, and MMP bands were quantitated relative to a conditioned media standard from HT-1080 cells. Gelatinase activity in both diabetic mice and nondiabetic mice increased after the mice were wounded. However, levels of latent gelatinases peaked earlier in the diabetic wounds, and there was more active MMP-2 and MMP-9 in the wounds of the diabetic mice than in the wounds of the nondiabetic mice. Because the higher gelatinase activity in the wounds of the diabetic mice was similar to the higher levels of gelatinase reported in difficult-to-heal wounds such as ulcers and burns, this diabetic mouse model may be useful for studies of these proteinases and their inhibitors in impaired wound healing.

Survival of enterococci and staphylococci on hospital fabrics and plastic.

The transfer of gram-positive bacteria, particularly multiresistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE), among patients is a growing concern. One critical aspect of bacterial transfer is the ability of the microorganism to survive on various common hospital surfaces. The purpose of this study was to determine the survival of 22 gram-positive bacteria (vancomycin-sensitive and -resistant enterococci and methicillin-sensitive and -resistant staphylococci) on five common hospital materials: smooth 100% cotton (clothing), 100% cotton terry (towels), 60% cotton-40% polyester blend (scrub suits and lab coats), 100% polyester (privacy drapes), and 100% polypropylene plastic (splash aprons). Swatches were inoculated with 10(4) to 10(5) CFU of a microorganism, assayed daily by placing the swatches in nutritive media, and examining for growth after 48 h. All isolates survived for at least 1 day, and some survived for more than 90 days on the various materials. Smaller inocula (10(2)) survived for shorter times but still generally for days. Antibiotic sensitivity had no consistent effect on survival. The long survival of these bacteria, including MRSA and VRE, on commonly used hospital fabrics, such as scrub suits, lab coats, and hospital privacy drapes, underscores the need for meticulous contact control procedures and careful disinfection to limit the spread of these bacteria.

A survey of gram-negative bacteria survival on hospital fabrics and plastics.

One critical factor for the transmission of microorganisms from person to person or from the environment to a person (patient or health care worker) is the ability of the microbe to survive on an environmental surface. The purpose of this study was to determine the length of survival of various gram-negative bacteria on fabrics and plastics commonly used in hospitals. Seven materials were tested: smooth cotton (clothing), cotton terry (towels), 60% cotton-40% polyester blend (scrub suits and lab coats), polyester (drapes), 75% nylon-25% spandex (pressure garments), polyvinyl (splash aprons), and polyurethane (keyboard covers). The following bacteria were tested: Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, Serratia marcescens, Proteus mirabilis, Acinetobacter species, and Enterobacter species. Swatches of the materials were inoculated with defined amounts of bacteria and assayed at regular intervals. Survival was dependent on the bacterium, its inoculum size, and the material tested. At 102 microorganisms per swatch, bacteria survived from less than 1 hour to 8 days. At 10(4) to 10(5) bacteria per swatch, survival ranged from 2 hours to more than 60 days. These findings emphasize the need for careful disinfection and conscientious contact control procedures in areas that serve immunosuppressed individuals, such as patients with burn injuries.

The 1999 Lindberg award. 3% hydrogen peroxide for the gram-positive disinfection of fabrics.

Because of growing concern about the spread of antibiotic-resistant gram-positive bacteria in burn and trauma units, an inexpensive, safe, effective means of spot-disinfecting fabrics (such as privacy curtains) that remain in clinic or patient rooms as various patients use the rooms was sought. From comparisons of cost and safety data, 3% hydrogen peroxide was chosen to be tested for its efficacy in the control of these bacteria. Systematic laboratory testing used 30 antibiotic-resistant and sensitive staphylococci and enterococci and 4 common hospital fabrics: cotton (clothing), terry cloth (towels), cotton-polyester blend (scrub suits), and polyester (curtains). Without disinfection, bacteria survived for many hours to several days. After a single spraying with 3% hydrogen peroxide, all bacteria on all fabrics were dead within 5 to 120 minutes. On-site testing targeted privacy curtains in patients' rooms. Curtain edges that tended to be grabbed when moving the curtain showed a mixture of gram-positive and gram-negative bacteria (median, 22 bacteria/24 cm2). After these areas were sprayed with 3% hydrogen peroxide, no bacteria were found. It was concluded that spraying with 3% hydrogen peroxide is a safe, inexpensive, effective means of spot-disinfecting fabrics in patients' rooms; this simple procedure may limit the spread of potentially pathogenic antibiotic-resistant bacteria.

Gelatinase activity in keloids and hypertrophic scars.

Keloids and hypertrophic scars are characterized by excessive deposition of collagen, which may result from insufficient protein degradation. Little is known about the levels of two gelatinases, matrix metalloproteinase-2 (72 kD type IV collagenase) and matrix metalloproteinase-9 (matrix metalloproteinase-9; 92 kD type IV collagenase) in these abnormal scars. The purpose of this study was to determine levels of these proteinases in tissue from hypertrophic scars, keloids, and donor skin. Ten hypertrophic scar samples, 9 keloid samples, and 10 donor skin samples were frozen, pulverized, homogenized, clarified by centrifugation, and analyzed for matrix metalloproteinases by quantitative zymography. Identity of matrix metalloproteinases was determined using a conditioned media reference standard, molecular weight ladders, and Western blotting. Levels of matrix metalloproteinase-9 activity were very low or undetectable in all samples. However, matrix metalloproteinase-2 activity was significantly elevated in keloids and hypertrophic scars vs. donor samples: 2.6 and 3.9-fold increases for latent matrix metalloproteinase-2, 7.8 and 6.9-fold increases for active matrix metalloproteinase-2, respectively. We conclude that little matrix metalloproteinase-9 activity (the gelatinase involved in early tissue repair) is present in keloids and hypertrophic scars, while matrix metalloproteinase-2 activity (the gelatinase involved in prolonged tissue remodeling) is present in donor skin and is significantly increased in hypertrophic scars and keloids.

Efficacy of a rise in C-reactive protein serum levels as an early indicator of sepsis in burned children.

C-Reactive protein serum levels were measured in 57 pediatric patients with 3% to 92% total body surface area burns to determine whether a defined rise in C-reactive protein serum levels could indicate sepsis earlier in burn patients. A rise in C-reactive protein serum levels was defined as an increase of at least 3 mg/dL for 2 days or 10 mg for 1 day. Increases the first 2 days after the burn or the day after surgery were excluded, since these injuries increase C-reactive protein serum levels. Patients were defined as septic when they were on systemic antibiotics and exhibited at least two of 16 specific clinical parameters. C-Reactive protein serum levels correctly predicted sepsis 82% of the time (efficiency=82%). Nonseptic patients generally did not show increased C-reactive protein serum levels (specificity=69%). When sepsis did occur, it always was preceded by increased C-reactive protein (sensitivity=100%), and the increased C-reactive protein occurred 2.3+/-0.5 days before the patient was deemed septic clinically. Hence, a defined rise in C-reactive protein serum levels can predict sepsis sooner in burned children.

Effect of thermal injury on the adherence of Candida albicans to murine splenic tissue.

In a mouse model of thermal injury, an increase in burn size produced a decrease in the ratio of Candida albicans cells adherent to the marginal zone to those adherent to the white pulp of the spleen, an increase in the number of Candida cells in the circulation and in the kidneys, and an increase in mortality.