To explore the potential benefit of comparing results from two national surveillance networks.

Two prospective multicenter cohort studies of surgical wound infections (SWI).

Thirty-five and 62 acute-care hospitals in The Netherlands (NL) and Belgium (B), respectively, from October 1, 1991, to June 30, 1992.

The participation was equivalent in the two countries: 27% (NL) and 28% (B) of all acute-care hospitals.

Marked differences emerged between the Dutch and Belgian crude infection rates and the specific rates by wound class and other risk factors.

Because the case-mix in the countries is quite different, comparisons can be made only by specific surgical category. The results for inguinal hernia repair and for appendectomy are compared as an example.

In hemiorrhaphies, the difference in infection rate (0.4% [NL] versus 1.2% [B]) is not explained by differences in the distribution of risk factors. The shorter hospital stay in The Netherlands (4 days [NL] versus 6 days [B]), the more effective postdischarge surveillance in Belgium, and the fact that more than two thirds of the detected infections occurred after the first postoperative week probably can account for most of the difference. There was a striking difference in prophylaxis use (3.7% [ NL] versus 41.9% [B]).

In appendectomies, the Dutch patient population shows on average a higher risk profile, and surgery is urgent much more often in The Netherlands (78.3%) than in Belgium (49.2%). The infection rate is higher in The Netherlands, especially among the patients without prophylaxis, which again is employed less frequently there.

We conclude that international comparisons yield interesting insights regarding quality of care, reaching beyond the field of nosocomial infection prevention. This is an argument in favor of more harmonization between surveillance networks.

To determine the incidence of hepatitis C virus (HCV) infection among healthcare workers (HCWs) at a university hospital, the proportion of HCWs having non-A, non-B hepatitis (NANBH) who were anti-HCV positive, and the rate of HCV transmission following a HCV-positive needlestick injury.

Longitudinal analysis of a dynamic (cohort) population.

From 1980 through 1989, HCWs who had clinical NANBH were identified, and from 1987 through 1989, HCWs who reported a blood or body fluid exposure and the patients who were the source of the exposure were screened for antibodies to HCV.

A 732-bed, university hospital and outpatient clinics.

Over the 10-year period, six cases of occupationally acquired NANBH were observed, for an incidence of 21 cases per 100,000 HCWs per year (standardized incidence ratio, 2.96; 95% confidence interval [CI95], 1.83 to 4.36). Four of the six cases were confirmed to be HCV infection. From 1987 through 1989, 176 (12.7%) of 1,387 patients who were the source of an exposure were anti-HCV positive. Exposures that occurred in the emergency department were more likely to be anti-HCV positive than were exposures from all other locations (relative risk [RR] = 1.7; P= 0.009). Of HCWs who had an HCV-positive needlestick injury and whose serum had been tested for anti-HCV at least 5 months after the exposure, 3 (6.0%) of 50 seroconverted. From 1987 through 1989, the incidence of HCV infection among HCWs was 54 cases per 100,000 HCWs per year.

The incidence of clinical NANBH among HCWs in this study is approximately three times higher than that of non-HCWs. HCWs are at significant risk for exposure to and acquisition of HCV.

To survey hospital administrators regarding their opinions of an acceptable frequency of staff needlestick injury and the frequency that would prompt additional preventive action.

A simple anonymous questionnaire sent to 960 administrators with one reminder. Data were collected regarding hospital size and community role, whether human immunodeficiency virus (HIV)-infected patients had ever been treated, presence of an infection control practitioner, estimation of the proportion of staff vaccinated against hepatitis B, and opinions as to the acceptable frequency of needlestick accidents and the accident frequency requiring additional action.

240 public hospitals in New South Wales, Australia.

The executive officers, directors of medical services, directors of nursing, and safety officers of the hospitals surveyed.

The response rate was 50%. Administrators' opinions of acceptable accident frequency increased with hospital size and (independently of size) with experience with HIV-infected patients, and with the presence of a full-time infection control practitioner. Accident frequencies judged to require additional preventive action were higher than injury frequencies regarded as acceptable.

The hospital administrators surveyed accept staff needlestick injuries as inevitable, the more so in hospitals that have treated known HIV-infected patients and that have full-time infection control practitioners.

To determine the incidence and pattern of antibiotic use in a neonatal intensive care unit (NICU).

Prospective study of a one-month NICU cohort. Investigators visited each subject, checking nursing notes, antibiotic flow sheets, and laboratory data at each daily visit.

The NICU at Yale-New Haven Hospital, New Haven, Connecticut; a regional care, level 3 unit in a tertiary care medical center.

All infants admitted to the NICU for one month (n = 63) who resided in the unit for ≥ 24 hours.

75% of the infants had antibiotic treatment begun in the first 48 hours of life. The highest rate of antibiotic treatment starts was in premature infants with birthweight less than 1,500 g, 92% of whom received antibiotics in the first 48 hours. In the subsequent days of life the incidence of starting antibiotic treatment was low and sporadic and the prevalence of antibiotic treatment by day of life showed a sharp decline between the third and fourth days of life. Five cross-sectional studies in the nursery showed point-prevalence rates of antibiotic use to be 27% to 43% of the whole NICU population, highest in the intensive care sector of the unit and in those <72 hours of age.

The high incidence of antibiotic starts in this NICU was largely the result of universal treatment of premature infants beginning on the first day of life. The risk of infection in these infants is quite low; more information is needed concerning how to distinguish infants who do not require treatment. This study provides comparison data for NICUs compiling data on incidence and prevalence of antibiotic use and developing programs to limit antibiotic use.

To investigate a cluster of Serratia odorifera in a cardiothoracic surgery unit (CTSU) and to evaluate the applicability of three typing methods for this species.

During a surveillance surgical wound study, S odorifera was isolated from two patients in the CTSU. The patients' hospital charts were reviewed for the details of surgery and for common personnel, procedures, or medications. Cultures were obtained of water, soap, and unit dose medications from the CTSU, the operating room, and the surgical intensive care unit. The isolates' antibiograms, biotypes (Vitek identification card and API 20E), and patterns of chromosomal DNA (chrDNA) by pulsed-field gel electrophoresis (PFGE) were examined. S odorifera isolates from our organism collection were used as controls.

A 900-bed university hospital with a 22-bed CISU.

ChrDNA patterns of isolates from the two patients were identical, suggesting a possible nosocomial source. However, no source of organisms or mode of transmission was identified. Neither biotype nor antibiogram were useful for epidemiologically typing S odorifera, and PFGE was necessary to discriminate among isolates.

Although rarely isolated, S odorifera and other non- marcescens Serratia species may cause nosocomial outbreaks. PFGE of chrDNA seems to be a reliable method for epidemiologically typing this species.

Xanthomonas maltophilia is increasingly a cause of nosocomial infections. The mode of transmission of this organism is not well known.

To investigate clonality of X maltophilia isolates in epidemic and endemic settings.

An outbreak of X maltophilia was noted in the Intensive Care Nursery (ICN). Over the ensuing 9 months, hospitalwide isolates of X maltophilia were analyzed using contour-clamped homogeneous electric field (CHEF) gel electrophoresis of chromosomal DNA. This method was compared with the antibiogram for detecting differences and similarities among strains.

X maltophilia was recovered from 76 sites in 72 patients; 65 isolates from 61 patients and the hands of one nurse were available for analysis. CHEF demonstrated differences between most epidemiologically unrelated strains and similarity between most epidemiologically related strains. Several strains, initially presumed to be related because of temporal and spatial proximity of the patients involved, were determined by CHEF analysis to be independent infections. One pair of isolates whose Xbal CHEF patterns differed by a single band were differentiated clearly by Sspl. There was enough variation in the minimum inhibitory concentrations of selected antibiotics to allow typing of some strains. The antibiogram, however, did not group all of the ICN outbreak isolates with others found to be genetically identical by CHEF and it grouped 39 of 56 isolates with others not genetically the same.

Although it is a convenient and economical tool, the antibiogram has limitations. Analysis by CHEF should help to elucidate the epidemiological spread of X maltophilia in the hospital.

To investigate coagulase-negative staphylococcus (CONS) causing bacteremia in a neonatal intensive care unit (NICU).

A 14-month retrospective review of 47 infants in the NICU with CONS bacteremia was undertaken to determine CONS glycocalyx production, plasmid pattern, total DNA restriction fragment polymorphism, and clinical risk factors.

The isolates included 32 Staphylococcus epidermidis, six Staphylococcus haemolyticus, four Staphylococcus warneri, four Staphylococcus saprophyticus, and one Staphylococcus hominis. Sixty-five percent of S epidermidis produced glycocalyx; other species did not. Oxacillin resistance (52%) and the antibiograms of the CONS were consistent with other units in the hospital. Five similar CONS plasmid patterns were found among 16 isolates; 31 isolates had unique patterns. Extractions of total DNA from these isolates were digested using HindIII, HaeIII, and BstEII. Those with similar restriction fragment length patterns could not be linked as nosocomially transmitted among infants with bacteremia.

Our observations suggest that multiple strains of CONS infect infants in the NICU who have similar risk factors. Although current infection control practices limit transmission of a pathogen, they do not prevent CONS bacteremias.

To determine cost-effectiveness and protective efficacy of a program to identify and immunize susceptible hospital employees during a measles outbreak.

A cost analysis was made of blind measles-mumps-rubella (MMR) immunization versus directed MMR immunization based on 2,000 employees born after December 31, 1956. A directed MMR immunization program for susceptible employees was instituted. Actual costs of the program were calculated at the conclusion of the program.

A medical center complex with more than 4,000 employees, two acute care community hospitals, and a tertiary care children's hospital.

A directed MMR immunization program was projected to he less expensive than blind immunization ($23,106 versus $70,720). MMR vaccine was administered to 169 of 188 susceptible employees. Actual cost of the directed MMR immunization program was $25,384.

The directed MMR immunization program was cost-effective and prevented secondary cases among hospital employees during a community measles outbreak.

To compare liquid soap versus 4% chlorhexidine gluconate in 4% alcohol for the decontamination of bare or gloved hands inoculated with an epidemic strain of Clostridium difficile.

C difficile (6.7 log10 colony-forming units [CFU], 47% spores), was seeded onto bare or latex gloved hands of ten volunteers and allowed to dry. Half the volunteers initially washed with soap and half with chlorhexidine, followed by the other agent 1 week later. Cultures were done with Rodac plates at three sites on the hand: finger/thumbtips, the palmar surfaces of the fingers, and the palm. Statistical comparison was by paired Student’s t test.

On bare hands, soap and chlorhexidine did not differ in residual bacterial counts on the finger/thumbtips (log10 CFU, 2.0 and 2.1, P= NS) and fingers (log10 CFU, 2.4 and 2.5, P=NS). Counts were too high on bare palms to quantitate. On gloved hands, soap was more effective than chlorhexidine on fingers (log10 CFU 1.3 and 1.7, P<.01) and palms (log10 CFU 1.5 and 2.0, P<.01), but not finger/thumbtips (log10 CFU 1.6 with each, P=NS). Residual C difficile counts were lower on gloved hands than bare hands (P<0.01 to <0.0001).

The two agents did not differ significantly in residual counts of C difficile on bare hands, but on gloved hands residual counts were lower following soap wash than following chlorhexidine wash. These observations support the use of either soap or chlorhexidine as a handwash for removal of C difficile, but efficacy in the prevention of C difficile transmission must be determined by prospective clinical trials.

To describe an outbreak of salmonella food poisoning that probably was due to contamination of mashed potatoes by a foodhandler, which occurred despite a policy for routine surveillance stool cultures of kitchen employees.

A case control study of 223 individuals who ate the lunch meal on September 23, 1989, at the Jordan University Hospital (JUH) cafeteria.

Tertiary care university hospital in Amman, the capital of Jordan.

Individuals who developed loose stool or vomiting 6 to 72 hours after eating the lunch meal of September 23, 1989, at the JUH cafeteria.

Of 619 individuals, 183 fit the case definition (attack rate, 19.6%); 150 were employees, 26 were inpatients, and seven were visitors. Twelve other employees became sick 4 to 6 days later and probably were infected secondarily. The incubation period ranged from 16 to 72 hours in 183 instances. Symptoms included diarrhea (88%), fever (71%), abdominal pain (74%), dehydration (34%), and bloody stool (5%). Eighty-four were hospitalized. Cultures of eight food items were negative, but stool culture on 90 of 180 patients and 11 of 61 kitchen employees yielded Salmonella enteritidis group D.

A cohort study of 223 individuals revealed a food-specific attack rate of 72% for the steak and potato meal and 18% for the rice and meat meal (RR, 4; CI95, 2.62 to 6.24; P<0.01). Stratified analysis of the steak and potato meal revealed that the potatoes were implicated most strongly (RR, 1.93; CI95, 1.42 to 2.64; p<0.01). Cultures were obtained from all kitchen employees, and 11 of 61 grew Salmonella enteritidis group D. One asymptomatic, culture-positive employee prepared the mashed potatoes on September 23. All of these employees had negative stool cultures 3 months earlier.

This outbreak probably was caused by massive contamination of mashed potatoes by the contaminated hands of the foodhandler. Routine stool culture of foodhandlers is not cost-effective and should not be used as a substitute for health education and proper hygienic practices.

To identify factors associated with developing nosocomial bloodstream infection (NBI) and to identify factors associated with fatal outcome of NBI.

Prospective matched and unmatched case-control studies.

Songklanagarind Hospital, a 640-bed medical school and referral center in Songkla, Thailand.

During a two-year study period, 277 patients of 17,829 total admissions in the hospital services of medicine, surgery, pediatrics, and orthopedics acquired bloodstream infections during hospitalization. For the purpose of identifying factors associated with mortality attributed to NBI, patients who died from NBI were assigned as cases; patients who survived the infections were assigned as controls. For the purpose of identifying risk factors for acquisition of NBI, patients with NBI were considered as cases; patients with the same primary diagnosis as a case but without NBI were eligible to be case-matched controls.

Case fatality rate was 37.2% based on deaths attributed specifically to bloodstream infection. Patients who died from NBI, compared with those who survived such infections, were associated with inappropriate antibiotic treatment, infection caused by Klebsiella pneumoniae, and the medicine service. When comparison was made between 239 patients with bloodstream infections and 598 diagnosis-matched controls with no bloodstream infection, infection was found to be associated with old age, number of comorbidities, number of prior infections, neutropenia, duration of immunosuppressive drugs, and duration of indwelling intravenous catheter.

Awareness of the factors predisposing to NBI may permit better surveillance and better care. Although most of the factors associated with development of NBI or death from NBI are not subject to control, some factors are duration of immunosuppressive drugs, duration of indwelling intravenous lines, and choice of antibiotic treatment.

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.

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 quaternary 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.

Each disk received a 10 μL inoculum containing 1.0 × 104 to 7.0 × 104 plaque-forming units (PFU) of the virus suspended in 10% feces. The inoculum was dried for 1 hour and overlaid with 20 μL of either tap water or the test product.

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.

These findings emphasize the care needed in the selection of environmental surface disinfectants in preventing the spread of rotaviral infections.