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Biomedical subjects

S A Sattar

Publications and source records attributed to S A Sattar.

At least 37 records · Page 2Linked to original sources
PubMed1999

Impact of changing societal trends on the spread of infections in American and Canadian homes.

Infectious diseases continue to exert a heavy toll on human health even in industrialized countries. Recent data from the World Health Organization suggests that infectious diseases are the leading cause of death in the world. Many changing trends in our society have a known or potential impact on infectious disease spread and may have an impact on the normal routine of home hygiene. Important amongst these societal trends are increasing population and life expectancy, changes in urbanization, grouping of susceptibles, increased ambulatory and home care, increased immunosuppression, increased and faster travel, changes in technology, increasing antibiotic resistance as a result of misuse of antibiotics, changes in food and water consumption, and changes in personal cleaning, washing, and laundry practices. This review will highlight these factors and their impact on home hygiene and steps that may be needed to reduce the risk from infections.

Canada↗
PubMed1997

A new ozone-based method for virus inactivation: preliminary study.

The nebulization technique reported here could be used to inactivate viruses with ozone in large volumes of body fluids, such as plasma, partial blood and perhaps whole blood in a short time. Coliphage MS2 was used as a model because it is safe, easy to handle and more resistant to chemical disinfections than viruses such as HIV. The theoretical curves and experimental points, describing ozone inactivation of MS2, form a semi-sigmoid of congruent data. There was a > 7log10 reduction in MS2 viability and the possibilities of minimizing the ozone concentration required to kill viruses are indicated. The analysis was expanded to account for the interaction of ozone with a virus suspension in the shape of a thin film from the experimental findings of Bolton et al. We again find a semi-sigmoid of congruent data for their case, i.e. describing ozone inactivation of the influenza A virus (WSN strain) and the vesicular stomatitis virus versus time. For the method of nebulization, the exposure time of droplets with ozone is a few seconds, whereas for the thin film method the exposure time is measured in hours.

Antiviral Agents↗
PubMed1996

Ex vivo protocol for testing virus survival on human skin: experiments with herpesvirus 2.

We report an ex vivo method, which uses pieces of human skin excised during routine plastic surgery, for testing survival of hazardous pathogens. Using this procedure, we compared the survival of human herpesvirus 2 on human skin and on metal disks. At the physiological skin temperature of 32 degrees C, the half-life of the virus on skin was 1.44 h while on metal disks it was 0.36 h. Even at ambient temperature (22 degrees C), the virus lost infectivity faster (half-life = 0.96 h) on metal disks than on the skin at 32 degrees C. The method described could be used to assess the survival of other human pathogens on skin and to evaluate the germicidal activity of handwashing agents and other topicals.

Adult↗
PubMed1996

In-hospital evaluation of 7.5% hydrogen peroxide as a disinfectant for flexible endoscopes.

The effectiveness of Sporox (Reckitt and Colman Inc, New Jersey), a 7.5% solution of hydrogen peroxide, was compared with that of Cidex (Johnson & Johnson), a 2% solution of alkaline glutaraldehyde, in the manual disinfection of flexible endoscopes at a large general hospital. For disinfection with Sporox, a soaking time of 10 mins at room temperature was used. The same disinfectant bath was used for nearly seven weeks and the Sporox level was monitored using reagent strips supplied with the product. Controls included endoscopes with precleaning (enzyme-detergent) but without any disinfection, and endoscopes that were precleaned and disinfected in Cidex only. A total of 3 mL of sterile normal saline was used for sampling each channel and immediately plated to detect aerobic and anaerobic bacteria as well as mycobacteria. There were 76 endoscopes sampled. Of these, 55 were disinfected in Sporox, 13 were disinfected in Cidex and eight were precleaned but not disinfected. None of the samples from endoscopes disinfected with either Sporox or Cidex yielded isolates generally regarded as pathogenic for humans. The findings of this in-hospital study indicate that Sporox is at least as efficacious as Cidex in the disinfection of flexible endoscopes between patients. In addition, the exposure time to Sporox was half as long compared with Cidex, and hydrogen peroxide is much less toxic to humans and the environment. Therefore, Sporox appears to have considerable potential as a safer substitute for glutaradehyde-based products in the decontamination of flexible endoscopes.

Anti-Infective Agents, Local↗
PubMed1995

Mycobactericidal testing of disinfectants: an update.

Tuberculosis, a major killer in developing countries, is on the rise again in industrialized nations. AIDS, increased use of immunosuppression and the emergence of multiple drug-resistant Mycobacterium tuberculosis (MDR-TB) have further enhanced its significance. TB is projected to cause 3.5 million deaths per year by 2000. Also, other types of mycobacteria are being incriminated in human infections with increasing frequency. Thus, the enhanced risk of nosocomial and iatrogenic spread of mycobacteria is forcing a review of infection control in general and claims of mycobactericidal activity of disinfectants in particular. Mycobacteria are more resistant to disinfection than enveloped viruses and other types of vegetative bacteria, but a proper comparison with non-enveloped viruses requires more data. Flaws in currently used protocols for mycobacterial activity are: (i) a lack of proper quantitation; (ii) unrealistically long contact times at higher than ambient temperatures; (iii) absence of a suitable organic load; (iv) ineffective neutralizers; (v) unsuitable surrogates for M. tuberculosis; (vi) improper recovery media; and (vii) inappropriate types of carriers. Furthermore, we have recently found a product meant for 14 day reuse to become non-mycobactericidal after only a week under actual use in an endoscopy unit. These considerations make the available data on product efficacy unreliable, especially in view of the increasing threat from MDR-TB. Recent findings suggest that the use of Mycobacterium terrae as a surrogate, better recovery media, flat surfaces as carriers, elimination of neutralizers, proper removal of cell clumps and a required > or = 4 log10 reduction in the number of colony forming units of the test bacterium after disinfectant treatment should make mycobacteridal tests more precise and reliable, thus making product registration and selection easier. There is also an urgent need to develop standardized protocols to determine the mycobactericidal activity of disinfectants under conditions of reuse.

Disease Reservoirs↗
PubMed1995

Catheter cleaning for re-use in intermittent catheterization: new light on an old problem.

Clean intermittent catheterization is a common method of urinary elimination for people with Spinal Cord Injuries. The methods of catheter cleaning for re-use, however, have not been validated with research studies. This study compared the effectiveness of Hydrogen Peroxide, vinegar, dishwashing detergent, and tap water alone to clean catheters contaminated with Pseudomonas aeruginosa and Escherichia coli. The effect of rinsing and drying before cleaning was also examined, as well as the effect of storage in paper or plastic bags after cleaning. Results indicated that rinsing and drying catheters immediately after use was the most effective at reducing bacteria to very near zero. Elements of a procedure are outlined, as well as plans for further development and testing of a rinse & dry procedure for catheter cleaning and re-use.

Catheters, Indwelling↗
PubMed1994

Studies on the survival of aerosolized bovine rotavirus (UK) and a murine rotavirus.

The effect of relative humidity (RH) and temperature on the survival of airborne bovine rotavirus UK isolate (BRV-UK) and a murine rotavirus (MRV) was studied. In any one experiment, the virus under test was suspended in tryptose phosphate broth (TPB) supplemented with uranine (physical tracer) and an antifoam, was aerosolized using a Collison nebulizer into the rotating drum with the RH at either low (30 +/- 5%), medium (50 + 5%) or high (80 +/- 5%) level at 20 +/- 1 degrees C. Following a 15-min period of viral aerosol stabilization, sequential samples of drum air were collected using an All-Glass Impinger (AGI) for 24 h post-aerosolization. Both of the rotavirus isolates were found to survive best at medium RH level and high RH was found least favorable for the survival of these aerosolized rotaviruses. The survival pattern of aerosolized MRV was found to be the best when compared with survival pattern of all animal and human rotavirus isolates studies performed under aerosolized conditions in our laboratory. The findings of these experiments confirm and extend our previous reports on the survival of other animal and human aerosolized rotaviruses and emphasize the fact that air may be one of the vehicles for their dissemination and could explain why it is difficult to control nosocomial outbreaks of rotavirus gastroenteritis and to keep animal colonies rotavirus-free.

Air Microbiology↗
PubMed1994

Feasibility of a combined carrier test for disinfectants: studies with a mixture of five types of microorganisms.

BACKGROUND: There is mounting concern regarding the efficacy of many germicides on the market because officially recognized germicidal tests for various classes of microorganisms vary widely and often lack reproducibility and proper quantitation. We report here a carrier method for simultaneously and quantitatively assessing the efficacy of liquid chemical germicides against a mixture of microorganisms of varying degrees of resistance. METHODS: In the test, each small glass cup (10 mm wide x 14 mm long) was contaminated with 10 microliters of a standardized mixture of Staphylococcus aureus, Mycobacterium bovis bacille Calmette-Guérin, Trichophyton mentagrophytes spores, Sabin poliovirus type 1, and Bacillus stearothermophilus spores in 5% fetal bovine serum. The inoculum was dried for 60 minutes under ambient conditions and covered with 60 microliters of the disinfectant under test or a balanced salt solution control for the desired contact time. The carrier was then placed in 2940 microliters of an eluent and the eluates assayed separately for the five microorganisms. Tap water was used to dilute the test product as needed. RESULTS: Of the 11 products tested, 2% alkaline glutaraldehyde, 0.6% sodium hypochlorite (about 5000 ppm free chlorine), and a 0.4% quarternary ammonium compound containing 23% hydrochloric acid were effective against all five challenge organisms. A hard-surface spray containing 0.1% o-phenylphenol with 79% ethanol was effective against all but bacterial spores; 70% (volume/volume) ethanol alone and povidone-iodine (1% available iodine) were effective against S. aureus, the mycobacterium, and the fungus; a 3% solution of peroxygen compounds was effective only against S. aureus and the poliovirus; 1.5% chlorhexidine gluconate, 0.06% quaternary ammonia compound, and 0.03% o-phenylphenol + 0.03% p-tertiary amylphenol could inactivate nothing but S. aureus; and 3% hydrogen peroxide was ineffective in all tests. CONCLUSIONS: This method shows promise for use with various classes of microorganisms, individually or as mixtures. Its application should enable the classification of germicides according to spectrum of activity.

Disinfectants↗
PubMed1994

Seasonality and prevalence of rotavirus in Al-Ain, United Arab Emirates.

BACKGROUND: Rotaviruses are the single most important causative agent of acute neonatal enteritis in most avian and mammalian species including humans. Rotaviruses infections have also been shown to be associated with the elderly, immunocompromised individuals and more recently with epidemic diarrheal illness in adults. OBJECTIVES: To study the incidence and the effect of seasonality on the prevalence of rotaviruses in Al-Ain, United Arab Emirates. STUDY DESIGN: A total of 650 stool samples submitted to the laboratories of two University Teaching Hospitals (Al-Ain and Tawam) and a private hospital (Oasis) were examined for the presence of rotaviruses from January 1990-December, 1992, using a commercially available latex agglutination assay. The meteorological data (temperature, relative humidity and rainfall) recorded during the sampling period was analyzed statistically to examine the effect of seasonality on the prevalence of rotavirus cases in Al-Ain, United Arab Emirates. RESULTS: Rotavirus was detected in 21.4% of the samples examined. The predominant number of positive cases (35%) were in the 7-12 months age group. It was interesting to find rotavirus-positive cases in as low an age group as < 3 months (3.6%) and as high as 10 years (8.04%). There was no significant difference on infection rates between male and female groups in the study. However, there was a significant difference between the national (38.18%) and non-national children (61.28%). The higher rate of the latter may be due to import of infections. There appeared to be a seasonal pattern of rotavirus occurrence in the cases studied, with a marked increase in the number of positive cases during the months when the relative humidity was low (25-45%) and there was no rainfall. CONCLUSIONS: Rotavirus was detected in all age groups with a predominance in 7-12 month age groups, and a higher incidence in non-nationals. There was a marked increase in the number of positive cases during the months when the relative humidity was low (25-45%) and there was no rainfall. These findings are discussed in relation to the epidemiology and prophylaxis of rotavirus infections.

Journal Article↗
PubMed1994

Interruption of rotavirus spread through chemical disinfection.

INTRODUCTION: Rotaviruses, which are among the most important infectious causes of acute diarrhea, frequently cause outbreaks in hospitals, daycare centers, schools, and nursing homes. These viruses can remain viable on inanimate surfaces for many days and infectious rotavirus particles have been recovered from hands and a variety of surfaces and objects. Casual contact can lead to the transfer of these viruses from contaminated to clean surfaces. Therefore, animate and inanimate surfaces may play a complementary role in the spread of these viruses. OBJECTIVE: In this study, we compared the capacity of a disinfectant spray (0.1% o-phenylphenol and 79% ethanol), a domestic bleach (6% sodium hypochlorite diluted to give 800 ppm free chlorine), a quarternary ammonium (quat)-based product (7.05% quat diluted 1:128 in tap water), and a phenol-based product (14.7% phenol diluted 1:256 in tap water) to interrupt the transfer of a human rotavirus (DS-1) from stainless steel disks to fingerpads of volunteers with a 10-second contact at a pressure of 1 kg/cm2. DESIGN: Each disk received a 10 microL inoculum containing 1.0 x 10(4) to 7.0 x 10(4) plaque-forming units (PFU) of the virus suspended in 10% feces. The inoculum was dried for 1 hour and overlaid with 20 microL of either tap water or the test product. RESULTS: A 10-minute exposure to tap water reduced the virus titer by 52.3% +/- 11.7%. The disinfectant spray was able to reduce virus infectivity by > 99.99% after a contact of 3 to 10 minutes. The loss in virus infectivity after a 10-minute treatment with the quat was almost the same (54.7% +/- 17.8%) as seen with tap water. The activities of the bleach and the phenolic were very similar with losses in PFU of 97.9% +/- 0.4% and 95% +/- 5.36%, respectively. No detectable virus was transferred to fingerpads from disks treated with disinfectant spray, the bleach, and the phenolic. Contact of the fingerpads with tap water- or quat-treated disks resulted in the transfer of 5.6% +/- 1.1% and 7.6% +/- 2.5% of the remaining infectious virus, respectively. CONCLUSION: These findings emphasize the care needed in the selection of environmental surface disinfectants in preventing the spread of rotaviral infections.

Adult↗
PubMed1993

Comparative in vivo efficiencies of hand-washing agents against hepatitis A virus (HM-175) and poliovirus type 1 (Sabin).

The abilities of 10 hygienic hand-washing agents and tap water (containing approximately 0.5 ppm of free chlorine) to eliminate strain HM-175 of hepatitis A virus (HAV) and poliovirus (PV) type 1 (Sabin) were compared by using finger pad and whole-hand protocols with three adult volunteers. A mixture of the two viruses was prepared in a 10% suspension of feces, and 10 microliters of the mixture was placed on each finger pad. The inoculum was allowed to dry for 20 min, and the contaminated area was exposed to a hand-washing agent for 10 s, rinsed in tap water, and dried with a paper towel. In the whole-hand protocol, the hands were contaminated with 0.5 ml of the virus mixture, exposed for 10 s to a hand-washing agent, washed, and dried as described above. Tryptose phosphate broth was used to elute any virus remaining on the finger pads or hands. One part of the eluate was assayed directly for PV with FRhK-4 cells, while the other part was first treated with a PV-neutralizing serum and then assayed for HAV with the same cell line. The results are reported as mean percentages of reduction in PFU compared with the amount of infectious virus detectable after initial drying.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Chemical disinfection to interrupt transfer of rhinovirus type 14 from environmental surfaces to hands.

Rhinoviruses can survive on environmental surfaces for several hours under ambient conditions. Hands can readily become contaminated after contact with such surfaces, and self-inoculation may lead to infection. Whereas hand washing is crucial in preventing the spread of rhinovirus colds, proper disinfection of environmental surfaces may further reduce rhinovirus transmission. In this study, the capacities of Lysol Disinfectant Spray (0.1% o-phenylphenol and 79% ethanol), a domestic bleach (6% sodium hypochlorite diluted to give 800 ppm of free chlorine), a quaternary ammonium-based product (7.05% quaternary ammonium diluted 1:128 in tap water), and a phenol-based product (14.7% phenol diluted 1:256 in tap water) were compared in interrupting the transfer of rhinovirus type 14 from stainless steel disks to fingerpads of human volunteers upon a 10-s contact at a pressure of 1 kg/cm2. Ten microliters of the virus, suspended in bovine mucin (5 mg/ml), was placed on each disk, and the inoculum was dried under ambient conditions; the input number on each disk ranged from 0.5 x 10(5) to 2.1 x 10(6) PFU. The dried virus was exposed to 20 microliters of the test disinfectant. The Lysol spray was able to reduce virus infectivity by > 99.99% after a contact of either 1 or 10 min, and no detectable virus was transferred to fingerpads from Lysol-treated disks. The bleach (800 ppm of free chlorine) reduced the virus titer by 99.7% after a contact time of 10 min, and again no virus was transferred from the disks treated with it.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Bactericidal, virucidal, and mycobactericidal activities of reused alkaline glutaraldehyde in an endoscopy unit.

Baths with 2% alkaline glutaraldehyde are often reused for 14 days to decontaminate flexible fiberoptic endoscopes (FFEs) between patients, but the effect of such reuse on the disinfectant's activity has not been known. Many busy endoscopy units also disinfect FFEs with contact times shorter than those recommended by the disinfectant manufacturer. We therefore collected samples of the disinfectant over the 14-day reuse period from two manual and one automatic bath used for bronchoscopes and gastroscopes at a local hospital. Control samples were also collected from a manual bath of 2% alkaline glutaraldehyde which did not receive any endoscopes. The germicidal activities of the samples were assessed in a carrier test against a mixture of hepatitis A virus, poliovirus 1 (Sabin), and Pseudomonas aeruginosa; the mixture also contained either Mycobacterium bovis or Mycobacterium gordonae. Bovine serum (5%) was the organic load. The criterion of efficacy was a minimum of a 3-log10-unit reduction in the infectivity titers of the organisms tested. The initial disinfectant concentration in all the baths was nearly 2.25%; it became about 1.8% in the control bath and fell to approximately 1% in the three test baths after 14 days. No protein was detected in the control bath, while its concentration rose gradually in the test baths to a maximum of 1,267 micrograms/ml after 14 days. With a contact time of 10 min at 20 +/- 2 degrees C, all the samples from the control bath were effective against all the test organisms and all the samples from all the test baths were also effective against P. aeruginosa. With a contact time of 10 or 20 min at 20+/-2 degrees C, the virucidal and mycobactericidal activities of the samples from the test baths showed broad-spectrum germicidal activity when the contact time was increased to 45 min and the temperature was raised to 25 degrees C. These findings emphasize the care needed in the disinfection of FFEs, especially in view of the increasing threat of AIDS and the resurgence of tuberculosis.

Bacteria↗
PubMed1992

Survival of hepatitis A virus on human hands and its transfer on contact with animate and inanimate surfaces.

The survival of hepatitis A virus (HAV; strain HM175) on the hands of five volunteers was determined by depositing 10 microliters of fecally suspended virus on each fingerpad and eluting the inoculum after 0, 20, 60, 120, 180, and 240 min. The amount of virus recovered from each fingerpad at 0 min was approximately 6.0 x 10(4) PFU. At the end of 4 h, 16 to 30% of the initially recoverable virus remained detectable on the fingerpads. HAV inocula (10 microliters; approximately 1.0 x 10(4) PFU) placed on fingerpads or 1-cm-diameter metal disks were used to determine virus transfer to clean surfaces upon a 10-s contact at a pressure of nearly 0.2 kg/cm2. When the inoculum was dried for 20 min, virus transfer from fingerpad to fingerpad, fingerpad to disk, and disk to fingerpad ranged from 2,667 to 3,484 PFU, while 0 to 50 PFU could be transferred after 4 h of drying. Elevation of the contact pressure alone from 0.2 to 1.0 kg/cm2 resulted in an approximately threefold increase in the amount of virus transferred. Incorporation of friction (10 half turns of the finger during 10 s of contact) with the low and high levels of pressure gave two- and threefold increases in the PFU of virus transferred, respectively. Pressure and friction were found to significantly affect HAV transfer (F = 33.98; P less than 0.05), irrespective of the mode of transfer used. No statistically significant interaction was observed between mode of transfer and pressure or friction. The findings of this quantitative study suggest that human hands may play an important role in the direct as well as the indirect spread of HAV.

Adult↗
PubMed1992

Studies on the stability of a human adenovirus-rabies recombinant vaccine.

Human adenovirus type 5 containing the rabies virus glycoprotein gene (rHAd-RG1) has potential for the oral vaccination of animals. The stability of this recombinant was tested indoors and outdoors by measuring the loss in virus infectivity. Under indoor conditions the stability of the recombinant virus was studied in an egg yolk-containing commercial stabilizer and a simple buffered salt solution (EBSS; Earle's balanced salt solution) at 4 degrees C and room temperature (24-25 degrees C). Over 16 days, there was a more rapid loss in virus titer at room temperature than at 4 degrees C in both suspending media; however, these differences were slight and may be significant when the overall stability of the vaccine is considered. When the virus was mixed with either 10% (w/v) fox or skunk feces or EBSS, placed on stainless steel disks and the disks kept under ambient conditions (air temperature 24-25 degrees C; relative humidity 45-50%), there was a more rapid decline in virus titer in the fecal suspensions (3% remained after 72 h) than in EBSS (26% remained after 72 h). When bait-coated blister packs of the vaccine were placed in an outdoor location in the fall (October) season, there was a larger drop in the virus titer for vaccines placed in the sun (54% over 32 days) than for those in the shade (40% over 32 days). Incorporating proteinaceous stabilizers in the vaccine samples for outdoor study showed virus stability was not enhanced in their presence.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenoviruses, Human↗