To evaluate three different DNA techniques for typing nonfermentative gram-negative bacilli isolated from Latin American hospitals.

One hundred twenty-six nonfermentative gram-negative bacilli were typed.

Pseudomonas aeruginosa (n = 64) and Acinetobacter baumannii (n = 42) samples were obtained from blood cultures of patients admitted to 10 medical centers in Latin America during 1998 and Stenotrophomonas maltophilia (n = 20) samples were obtained from patients admitted to the Hospital São Paulo between 1999 and 2001.

All samples were typed using automated ribotyping, PFGE, and ERIC-PCR. The discriminatory power for each technique was calculated using Hunter's generalized formula.

All strains could be typed by automated ribotyping and ERIC-PCR, but two strains (1.6%) were not typeable by PFGE. All three techniques showed 100% reproducibility. The time to obtain the results was shorter for automated ribotyping and ERIC-PCR compared with PFGE. Likewise, the costs for ERIC-PCR and PFGE were lower than those for automated ribotyping. The interpretation of results was more complicated and more difficult with ERIC-PCR than with both PFGE and automated ribotyping. All techniques presented excellent discriminatory power for P. aeruginosa (0.98). PFGE presented the highest discriminatory power (0.94) for A. baumannii, and both PFGE and ERIC-PCR showed higher discriminatory power (0.90 for both) than automated ribotyping (0.82) for S. maltophilia.

PFGE showed the highest discriminatory power for typing these nonfermentative gram-negative bacilli. However, automated ribotyping and ERIC-PCR can provide results in a shorter time period with similar discriminatory power.

In August 2002, the Oklahoma State Department of Health received a report of six patients with unexplained hepatitis C virus (HCV) infection treated in the same pain remediation clinic. We investigated the outbreak's extent and etiology.

We conducted a retrospective cohort study of clinic patients, including a serologic survey, interviews of infected patients, and reviews of medical records and staff infection control practices. Patients received outpatient pain remediation treatments one afternoon a week in a clinic within a hospital. Cases were defined as HCV or hepatitis B virus (HBV) infections among patients who reported no prior diagnosis or risk factors for disease or reported previous risk factors but had evidence of acute infection.

Of 908 patients, 795 (87.6%) were tested, and 71 HCV-infected patients (8.9%) and 31 HBV-infected patients (3.9%) met the case definition. Multiple HCV genotypes were identified. Significantly higher HCV infection rates were found among individuals treated after an HCV-infected patient during the same visit (adjusted odds ratio [AOR], 6.2; 95% confidence interval [CI95], 2.4–15.8); a similar association was observed for HBV (AOR, 2.9; CI95, 1.3–6.5). Review of staff practices revealed the nurse anesthetist had been using the same syringe–needle to sequentially administer sedation medications to every treated patient each clinic day.

Reuse of needles–syringes was the mechanism for patient-to-patient transmission of HCV and HBV in this large nosocomial outbreak. Further education and stricter oversight of infection control practices may prevent future outbreaks.

To evaluate an antimicrobial dressing consisting of hydrophilic polyurethane foam with chlorhexidine gluconate for activity against several antibiotic-resistant clinical isolates as well as American Type Culture Collection reference strains using zone of inhibition assays.

Sterile foam samples with chlorhexidine gluconate and untreated controls were transferred onto inoculated agar plates. Plates were incubated at 35°C to 37° C for 24 hours and examined for zones of inhibition around the foam samples.

Polyurethane foam with chlorhexidine gluconate showed antimicrobial activity in vitro against all of the challenge organisms including antibiotic-resistant clinical isolates.

The data from this in vitro study support the hypothesis that polyurethane foam with chlorhexidine gluconate has an antimicrobial effect against antibiotic-resistant Staphylococcus and Enterococcus species, as well as Candida species.

From April to June 2001, an outbreak of extended-spectrum beta-lactamase (ESBL)–producing Klebsiella pneumoniae infections was investigated in our neonatal intensive care unit.

Cultures of the gastrointestinal tracts of patients, the hands of healthcare workers (HCWs), and the environment were performed to detect potential reservoirs for ESBL-producing K. pneumoniae. Strains of K. pneumoniae were typed by pulsed-field gel electrophoresis using Xbal. A case–control study was performed to determine risk factors for acquisition of the outbreak clone (clone A); cases were infants infected or colonized with clone A and controls (3 per case) were infants with negative surveillance cultures.

During the study period, 19 case-infants, of whom 13 were detected by surveillance cultures, harbored clone A. The overall attack rate for the outbreak strain was 45%; 9 of 19 infants presented with invasive disease (n = 6) or developed invasive disease (n = 3) after colonization was detected. Clone A was found on the hands of 2 HCWs, 1 of whom wore artificial nails, and on the designated stethoscope of a case-infant. Multiple logistic regression analysis revealed that length of stay per day (odds ratio [OR], 1.05; 95% confidence interval [CI95], 1.02 to 1.09) and exposure to the HCW wearing artificial fingernails (OR, 7.87; CI95, 1.75 to 35.36) were associated with infection or colonization with clone A.

Short, well-groomed, natural nails should be mandatory for HCWs with direct patient contact.

To review evidence regarding the effectiveness of control measures in reducing transmission of methicillin-resistant Staphylococcus aureus (MRSA) in hospitals.

Literature review and surveillance cultures of hospitalized patients at high risk for MRSA colonization or infection.

A 500-bed, university-affiliated, community teaching hospital.

The percentage of nosocomial S. aureus infections caused by MRSA increased significantly between 1982 and 2002, despite the use of various isolation and barrier precaution policies. The apparent ineffectiveness of control measures may be due to several factors including the failure to identify patients colonized with MRSA For example, cultures of stool specimens submitted for Clostridium difficile toxin assays at one hospital found that 12% of patients had MRSA in their stool, and 41% of patients with unrecognized colonization were cared for without using barrier precautions. Other factors include the use of barrier precaution strategies that do not account for multiple reservoirs of MRSA, poor adherence of healthcare workers (HCWs) to recommended barrier precautions and handwashing, failure to identify and treat HCWs responsible for transmitting MRSA, and importation of MRSA by patients admitted from other facilities. Control programs that include active surveillance cultures (ASCs) of high-risk patients and use of barrier precautions have reduced MRSA prevalence rates and have been cost-effective. Using a staged approach to implementing ASCs can minimize logistic problems.

MRSA control programs are effective if they include ASCs of high-risk patients, use of barrier precautions when caring for colonized or infected patients, hand hygiene, and treating HCWs implicated in MRSA transmission.

To assess the knowledge, beliefs, and practices of neonatal intensive care unit (NICU) healthcare workers (HCWs).

Self-administered survey.

A 55-bed NICU.

NICU HCWs (N = 215).

The response rate was 68%. Ninety-two percent knew central venous catheters (CVCs) should be capped, clamped, or connected to running fluids at all times. Ninety-five percent knew when to change gloves. Thirty-one percent knew the recommended duration for handwashing. Most HCWs believed sterile technique in CVC care (96%), gloves (91%), and handwashing (99%) prevent nosocomial infection (NI). Sixty-seven percent used sterile barriers to insert CVCs, 76% reported wearing gloves, 81% reported routine handwashing, 35% knew that bacterial hand counts are higher with rings, 30% knew that long fingernails are associated with higher gram-negative bacterial hand contamination, and 35% knew that artificial fingernails are associated with higher gram-negative bacterial hand contamination. Most (93%) believed HCWs can affect outcomes of patients with NIs. Fewer believed rings (40%), artificial fingernails (61%), and long fingernails (48%) play a role in NIs, or that policies concerning number of rings (50%), cutting fingernails (35%), or prohibiting artificial fingernails (47%) would prevent NIs. Sixty-one percent of HCWs regularly wore at least one ring to work, 56% wore their fingernails shorter than the fingertip, and 8% wore artificial fingernails.

A disconnect existed between CVC knowledge and beliefs and practice. HCWs did not know the relationship between bacterial hand counts and rings and fingernails, and did not believe rings or long or artificial fingernails increased the risk of NIs.

To analyze a method that identifies potentially preventable nosocomial infections, as a tool to evaluate the performance of infection control programs through quantification of their potential for reducing nosocomial infections.

The database of the Study of the Prevalence of Nosocomial Infections in Spain (EPINE) was reanalyzed. The method was based on the use of false negatives of the classification table obtained from application of a fixed multiple logistic regression model, as an estimator of the number of potentially preventable nosocomial infections.

The calculated number of patients with preventable infections was 7,493, which constituted 21.6% of the infected patients. Among hospital areas, intensive care had the lowest preventability rate (4.6%), whereas gynecology and obstetrics had the highest (40.6%). There was a significant inverse exposure-effect relationship between the proportion of preventable infections and the National Nosocomial Infections Surveillance (NNIS) System risk index. No correlation was observed between the prevalence of patients with nosocomial infection and the percentage of preventable infections.

This analysis suggests that fewer nosocomial infections may be preventable in Spanish hospitals than previously assumed.

To determine the impact of interventions using standing orders and computerized reminders to physicians on inpatient pneumococcal vaccination rates relative to a control group.

Open trial of the following approaches, each on a different ward: (1) standing orders for vaccination of eligible consenting patients, (2) computerized reminders to physicians, and (3) usual practice.

Four hundred twenty-four patients were admitted to three 30-bed inpatient medical wards during a 4-month period in 1999 at one hospital. Unvaccinated patients 65 years or older and competent to give oral consent were included.

A pharmacist activated a standing orders protocol for vaccination of all eligible consenting patients on one ward and computerized reminders to physicians on a second ward. A third ward served as a control group.

Forty-two patients met inclusion criteria and accepted vaccination in the standing orders arm versus 35 patients in the computerized reminder arm. Vaccination rates on the standing orders ward included 98% of those eligible and accepting vaccination, 73% of eligible patients, and 28% of all patients admitted. Rates on the computerized reminder ward were 23%, 15%, and 7%, respectively. All of the rates from the standing orders ward were significantly greater than those from the computerized reminder ward (P < .0001). Only 0.6% of all patients on the control arm were vaccinated.

Although both interventions were effective in increasing inpatient pneumococcal vaccination rates relative to baseline practice, physician independent initiation of standing orders was clearly more effective.

To investigate a hepatitis C virus (HCV) outbreak in a hemodialysis unit and determine the source of transmission.

We have prospectively investigated the epidemiology of hemodialysis-related HCV infection in a single unit since 1989. In September 2000, acute hepatitis C (AH-C) was diagnosed in 5 patients by alanine aminotransferase elevation and HCV genotype lb viremia without antibody to HCV. We surveyed the epidemiologic situation and performed polymerase chain reaction sequence analysis of the HCV 5'-noncoding (5'NC) region in the patients for comparison with 9 patients with chronic HCV genotype 1b viremia.

Sequence analysis of the 5'NC region showed the consistency in the 5 independent clones from each AH-C patient and those from each chronic HCV viremia patient and no quasispecies over time in the clones of any of 14 analyzed patients. All AH-C patients had the same sequencing of the 6 variations in the region with the only other patient. A saline ampoule, used for heparin solution during hemodialysis, had a recap function. It was difficult to determine whether the ampoule was new or had already been used. The source-patient often underwent hemodialysis before the AH-C patients and most of their hemodialysis-related medicine was prepared during the source-patient's treatment. These findings suggested a high possibility that the AH-C patients shared a single heparin–saline solution ampoule contaminated by HCV from the source-patient.

Nosocomial HCV infection occurred as a result of poor infection control practice when a patient with chronic HCV viremia received treatment prior to other hemodialysis patients.

To evaluate the effect of education and performance feedback regarding compliance with catheter care and handwashing on rates of catheter-associated urinary tract infection (UTI) in intensive care units (ICUs).

Two level III adult ICUs in a private healthcare facility in Argentina.

All adult patients admitted to the study units who had a urinary catheter in place for at least 24 hours.

A prospective, open trial in which rates of catheter-associated UTI determined during a baseline period of active surveillance without education and performance feedback were compared with rates of catheter-associated UTI after imple-menting education and performance feedback.

There were 1,779 catheter-days during the baseline period and 5,568 catheter-days during the intervention period. Compliance regarding prevention of compression of the tubing by a leg improved (from 83% to 96%; relative risk [RR], 1.15; 95% confidence interval [CI95], 1.03 to 1.28; P = .01) and so did compliance with handwashing (from 23.1% to 65.2%; RR, 2.82; CI95, 2.49 to 3.20; P<.0001). Catheter-associated UTI rates decreased significantly from 21.3 to 12.39 per 1,000 catheter-days (RR, 0.58; CI95, 0.39 to 0.86; P = .006).

Implementing education and performance feedback regarding catheter care measures and handwashing compliance was associated with a significant reduction in catheter-associated UTI rates. Similar programs may help reduce catheter-associated UTI rates in other Latin American hospitals.

To determine the attitudes, policies, and barriers for requiring annual versus voluntary influenza vaccinations for the staff of healthcare institutions in North Carolina.

Five different types of institutions serving at-risk elderly populations throughout North Carolina were chosen for study, including hospitals, home health agencies, nursing homes, dialysis centers, and assisted living facilities. Infection control managers completed a 45-question telephone survey on policies for annual influenza vaccinations for employees, incentives to encourage immunizations, support for mandatory influenza vaccinations for workers, barriers to employee vaccinations, and support for a state law to mandate influenza immunizations for employees with patient care contact.

Of 312 institutions, 268 (86%) participated in the study. Only 38% of institutions reported having formal written employee influenza vaccination policies, and only 2% actually mandated annual employee vaccinations. Reported barriers to increasing healthcare worker annual influenza vaccinations included “fear of side effects” and “perceived ineffectiveness of the flu vaccine.” Almost half of the respondents would support mandating influenza vaccinations for all healthcare workers with direct patient contact.

A state-wide survey of the receptivity, policies, and implications of mandated employee influenza vaccinations among healthcare institutions serving the elderly in North Carolina found written policies uncommon and most of the mechanisms used to increase vaccinations voluntary. Efforts should be tailored to individuals, institutions, and healthcare systems to dramatically increase employee immunization rates.

To determine the frequency of conjunctival colonization, identify the colonizing flora, and correlate culture results with physical findings in infants in a NICU

Surveillance study.

Level III NICU of a large university teaching hospital.

All infants admitted for longer than 24 hours during a 26-week period.

Weekly bacterial conjunctival cultures were performed for all infants. The conjunctival appearance at the time of culture was recorded. The frequency, identity, and correlation of culture results with physical findings were determined.

One thousand ninety-one cultures were performed for 319 infants: 133 (42%) had no positive cultures and 186 (58%) had at least one positive culture. Culture analysis revealed that 411 (38%) were positive and yielded 494 isolates comprising more than 18 bacterial species. Bacteria most commonly isolated included coagulase-negative Staphylococcus (CoNS) (75%), viridans group streptococci (8.7%), Staphylococcus aureus (3.8%), Enterococcus species (2.6%), and Serratia marcescens (2.4%). The frequency of non-CoNS isolates increased significantly during the first 6 weeks of patient hospital stay (6% [1 to 3 weeks] to 12% [4 to 6 weeks]; P = .01), with an increasing trend to 15 weeks (18%). Correlation of bacteriologic results with physical findings demonstrated that infants with non-CoNS isolates exhibited conjunctival edema, erythema, or exudates more frequently than did infants with CoNS alone (30% vs 13%; P = .0001).

Conjunctival colonization was common among infants in a NICU. Prolonged hospitalization predisposes to colonization with potentially pathogenic organisms. Physical findings were more likely in patients with non-CoNS conjunctival isolates.

To describe the rate, risk factors, and outcome of ventilator-associated pneumonia (VAP) in pediatric patients.

This prospective surveillance study of VAP among all patients receiving mechanical ventilation for 48 hours or more admitted to a pediatric intensive care unit (PICU) in Saudi Arabia from May 2000 to November 2002 used National Nosocomial Infections Surveillance (NNIS) System definitions.

Three hundred sixty-one eligible patients were enrolled. Most were Saudi with a mean age of 28.6 months. Thirty-seven developed VAP. The mean VAP rate was 8.87 per 1,000 ventilation-days with a ventilation utilization rate of 47%. The mean duration of mechanical ventilation was 21 days for VAP patients and 10 days for non-VAP patients. The mean PICU stay was 34 days for VAP patients and 15 days for non-VAP patients. Among VAP patients, Pseudomonas aeruginosa was the most common organism, followed by Staphylococcus aureus. Other gram-negative organisms were also encountered. There was no significant difference between VAP and non-VAP patients regarding mortality rate. Witnessed aspiration, reintubation, prior antibiotic therapy, continuous enteral feeding, and bronchoscopy were associated with VAP. On multiple logistic regression analysis, only prior antibiotic therapy, continuous enteral feeding, and bronchoscopy were independent predictors of VAP.

The mean VAP rate in this hospital was higher than that reported by NNIS System surveillance of PICUs. This study has established a benchmark for future studies of VAP in the pediatric intensive care population in Saudi Arabia. Additional studies from the region are necessary for comparison and development of preventive measures.

Rapid identification and investigation of potential outbreaks is key to limiting transmission in the healthcare setting. Manual review of laboratory results remains a cumbersome, time-consuming task for infection control practitioners (ICPs). Computer-automated techniques have shown promise for improving the efficiency and accuracy of surveillance. We examined the use of automated control charts, provided by an automated surveillance system, for detection of potential outbreaks.

A 656-bed academic medical center.

We retrospectively reviewed 13 months (November 2001 through November 2002) of laboratory-patient data, comparing an automated surveillance application with standard infection control practices. We evaluated positive predictive value, sensitivity, and time required to investigate the alerts. An ICP created 75 control charts. A standardized case investigation form was developed to evaluate each alert for the likelihood of nosocomial transmission based on temporal and spatial overlap and culture results.

The 75 control charts were created in 75 minutes and 18 alerts fired above the 3-sigma level. These were independently reviewed by an ICP and associate hospital epidemiologist. The review process required an average of 20 minutes per alert and the kappa score between the reviewers was 0.82. Eleven of the 18 alerts were determined to be potential outbreaks, yielding a positive predictive value of 0.61. Routine surveillance identified 5 of these 11 alerts during this time period.

Automated surveillance with user-definable control charts for cluster identification was more sensitive than routine methods and is capable of operating with high specificity and positive predictive value in a time-efficient manner.

In August 2001, a cluster of MRSA skin infections was detected in a correctional facility. An investigation was conducted to determine its cause and to prevent further MRSA infections.

Case-control study.

A 200-bed detention center.

A case was defined as a detainee with a skin lesion from which MRSA was cultured from July 24 through December 31, 2001. Case-patients were identified by review of laboratory culture results and by skin lesion screening through point-prevalence survey and admission examination. Controls were randomly selected from an alphabetized list of detainees.

Medical staff implemented measures to improve skin disease screening, personal hygiene, wound care, and antimicrobial therapy.

Sixteen cases were identified: 11, 5, and 0 in the preintervention, peri-intervention, and postintervention periods, respectively. Seven case-patients and 19 controls were included in the case-control study. On multivariable analysis, working as a dormitory orderly (OR, 9.8; CI95, 0.74-638; P= .10) and a stay of longer than 36 days (OR, 6.9; CI95, 0.65-128.2; P = .14) were the strongest predictors for MRSA skin infection. The preintervention, peri-intervention, and postintervention MRSA infection rates were 11.6, 8.8, and 0 per 10,000 detainee-days, respectively. The rate of MRSA skin infections declined significantly between both the preintervention and peri-intervention periods and the postintervention period (P < .01 for both comparisons).

MRSA skin disease can become an emergent problem in a correctional facility. Interventions targeted at skin disease screening, appropriate antimicrobial treatment, and hygiene may decrease the risk of acquiring MRSA infection in correctional facilities.

To compare the public's knowledge and perception of SARS and the extent to which various precautionary measures were adopted in Hong Kong and Singapore.

Cross-sectional telephone survey of 705 Hong Kong and 1,201 Singapore adults selected by random-digit dialing.

Hong Kong respondents had significantly higher anxiety than Singapore respondents (State Trait Anxiety Inventory [STAI] score, 2.06 vs 1.77; P < .001). The former group also reported more frequent headaches, difficulty breathing, dizziness, rhinorrhea, and sore throat. More than 90% in both cities were willing to be quarantined if they had close contact with a SARS case, and 70% or more would be compliant for social contacts. Most respondents (86.7% in Hong Kong vs 71.4% in Singapore; P < .001) knew that SARS could be transmitted via respiratory droplets, although fewer (75.8% in Hong Kong vs 62.1% in Singapore; P < .001) knew that fomites were also a possible transmission source. Twenty-three percent of Hong Kong and 11.9% of Singapore respondents believed that they were “very likely” or “somewhat likely” to contract SARS during the current outbreak (P < .001). There were large differences between Hong Kong and Singapore in the adoption of personal precautionary measures. Respondents with higher levels of anxiety, better knowledge about SARS, and greater risk perceptions were more likely to take comprehensive precautionary measures against the infection, as were older, female, and more educated individuals.

Comparative psychobehavioral surveillance and analysis could yield important insights into generic versus population-specific issues that could be used to inform, design, and evaluate public health infection control policy measures.

The Victorian Infection Control Surveillance Project (VICSP) is a multicenter collaborative surveillance project established by infection control practitioners. Five public hospitals contributed data for patients undergoing coronary artery bypass graft (CABG) surgery.

To determine the aggregate and comparative interhospital surgical-site infection (SSI) rates for patients undergoing CABG surgery and the risk factors for SSI in this patient group.

Each institution used standardized definitions of SSI, risk adjustment, and reporting methodology according to the National Nosocomial Infections Surveillance System of the Centers for Disease Control and Prevention. Data on potential risk factors were prospectively collected.

For 4,474 patients undergoing CABG surgery, the aggregate SSI rate was 7.8 infections per 100 procedures (95% confidence interval [CI95], 7.0-8.5), with individual institutions ranging between 4.5 and 10.7 infections per 100 procedures. Multivariate risk factor analysis demonstrated age (odds ratio [OR], 1.02; CI95, 1.01-1.04; P < .001), obesity (OR, 1.8; CI95, 1.4-2.3; P < .001), and diabetes mellitus (OR, 1.6; CI95, 1.2-2.1; P < .001) as independent predictors of SSI. Three hundred thirty-four organisms were isolated from 296 SSIs. Of the total SSIs, methicillin-resistant Staphylococcus aureus was isolated from 32%, methicillin-sensitive S. aureus from 24%, gram-negative bacilli (eg, Enterobacter and Escherichia colt) from 18%, and miscellaneous organisms from the remainder.

We documented aggregate and comparative SSI rates among five Victorian public hospitals performing CABG surgery and defined specific independent risk factors for SSI. VICSP data offer opportunities for targeted interventions to reduce SSI following cardiac surgery.

To compare the costs with the benefits of using chlorhexidine gluconate dressings on central venous catheters and to determine the effectiveness of these dressings in reducing local infections and catheter-related bloodstream infections (CRBSIs), costs, and mortality.

Cost–benefit analysis using randomized, controlled trial data on chlorhexidine dressing prevention of local infection and CRBSI, data on cost of chlorhexidine dressing versus standard treatment, data on averted cost of treating local infection and CRBSI, and data on mortality attributable to CRBSI. Decision analysis evaluated averted CRBSI treatment cost per patient resulting from chlorhexidine dressing use. Sensitivity analyses demonstrated net benefit of chlorhexidine dressing, varying baseline rate of CRBSI, incremental cost of treating CRBSI, and number of catheters, and evaluated mortality preventable through chlorhexidine dressing use, varying baseline rate of CRBSI, number of catheters, and mortality attributable to CRBSI.

Patients of all Philadelphia area hospitals and one Philadelphia academic medical center.

Estimated potential annual U.S. net benefits from chlorhexidine dressing use ranged from $275 million to approximately $1.97 billion. Cost–benefit findings persisted in sensitivity analyses varying baseline rate of CRBSI, incremental cost of treating CRBSI, and overall number of catheters used. Preventable mortality analyses showed potential decreases of between 329 and 3,906 U.S. deaths annually as a result of nationwide use of chlorhexidine dressing.

Chlorhexidine dressings would reduce costs, local infections and CRBSIs, and deaths. Use of chlorhexidine dressings should be considered to prevent infections among patients with catheters.

To investigate environmental contamination by extended-spectrum beta-lactamase-producing Enterobacteriaceae and to perform a comparative molecular analysis of clinical and environmental strains.

A 17-bed cardiac surgery intensive care unit of a 480-bed university teaching hospital.

Following an outbreak of extended-spectrum beta-lactamase-producing Enterobacteriaceae, an environmental survey revealed extensive contamination of the environment (particularly faucets, sink drains, and the joints of the countertops) by extended-spectrum beta-lactamase-producing Enterobacteriaceae. Environmental strains were compared with clinical strains by pulsed-field gel electrophoresis and randomly amplified polymorphic DNA.

A total of 62 environmental strains belonging to 4 species of extended-spectrum beta-lactamase-producing Enterobacteriaceae were analyzed and compared with 43 clinical strains obtained from 34 patients. Comparative molecular analysis revealed 4 identical or closely related patterns (3 from Klebsiella oxytoca and 1 from Enterobacter cloacae) between environmental and clinical strains.

Moist surfaces may serve as sources of multiply resistant Enterobacteriaceae in the intensive care unit. Identification and disinfection of such sources may therefore be helpful in prevention and control of outbreaks.

Detection of colonized patients is important for implementing control measures for methicillin-resistant Staphylococcus aureus (MRSA). Laboratory detection of MRSA carriers is increased by the use of selective screening media, helping control dissemination of such organisms.

To evaluate three different media, including selective and nonselective media, in the detection of MRSA from clinical specimens of patients of an intensive care unit (ICU).

Adult patients in the ICU of the Hospital Mae de Deus, Porto Alegre, Brazil.

A total of 224 specimens were obtained from the nares of patients and plated on blood agar, mannitol sait agar containing 2 μg/mL of oxacillin (MSAO), and oxacillin resistance screening agar base (ORSAB). The presence of MRSA was investigated in typical colonies growing on the three types of media. Discrepant results were resolved by detection of the mecA gene by polymerase chain reaction and the modified penicillin binding protein known as PBP2'.

MRSA was detected in 32 (14.3%) of 224 specimens. Blood agar, MSAO, and ORSAB detected MRSA in 17, 31, and 28 specimens, respectively. After the coagulase test, no false resistance was observed.

MSAO and ORSAB performed equivalently in the detection of MRSA of colonized patients and require a single supplementary test (coagulase) to confirm MRSA.