Bacterial contamination of health care workers' white coats.

BACKGROUND: Patient-to-patient transmission of nosocomial pathogens has been linked to transient colonization of health care workers, and studies have suggested that contamination of health care workers' clothing, including white coats, may be a vector for this transmission. METHODS: We performed a cross-sectional study involving attendees of medical and surgical grand rounds at a large teaching hospital to investigate the prevalence of contamination of white coats with important nosocomial pathogens, such as methicillin-sensitive Stapylococcus aureus, methicillin-resistant S aureus (MRSA), and vancomycin-resistant enterococci (VRE). Each participant completed a brief survey and cultured his or her white coat using a moistened culture swab on lapels, pockets, and cuffs. RESULTS: Among the 149 grand rounds attendees' white coats, 34 (23%) were contaminated with S aureus, of which 6 (18%) were MRSA. None of the coats was contaminated with VRE. S aureus contamination was more prevalent in residents, those working in inpatient settings, and those who saw an inpatient that day. CONCLUSION: This study suggests that a large proportion of health care workers' white coats may be contaminated with S aureus, including MRSA. White coats may be an important vector for patient-to-patient transmission of S aureus.

Prevalence of methicillin-resistant Staphylococcus aureus and Acinetobacter baumannii in a long-term acute care facility.

BACKGROUND: Patients in long-term acute care (LTAC) facilities often have many known risk factors for acquisition of antibiotic-resistant bacteria. However, the prevalence of resistance in these facilities has not been well described. METHODS: We performed a single-day, point-prevalence study of a 180-bed, university-affiliated LTAC facility in Baltimore to assess the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) and Acinetobacter baumannii in the anterior nares, perirectal area, sputum, and wounds. RESULTS: Among the 147 patients evaluated, we found a high prevalence of colonization by both MRSA (28%) and A baumannii (30%). Of the A baumannii isolates, 90% were susceptible to imipenem and 92% were susceptible to ampicillin-sulbactam. No isolates were resistant to both imipenem and ampicillin-sulbactam. CONCLUSION: The high prevalence of resistance found in this study supports the need for increased surveillance of patients in the LTAC environment. The fact that these patients are often frequently transferred to tertiary care facilities also supports the need for coordination and collaboration among facilities within the same health care system and the broader geographic area.

Detection of methicillin-resistant Staphylococcus aureus and vancomycin-resistant enterococci on the gowns and gloves of healthcare workers.

OBJECTIVE: To assess the rate of and the risk factors for the detection of methicillin-resistant S. aureus (MRSA) and vancomycin-resistant enterococci (VRE) on the protective gowns and gloves of healthcare workers (HCWs). METHODS: We observed the interactions between HCWs and patients during routine clinical activities in a 29-bed medical intensive care unit at the University of Maryland Medical Center, an urban tertiary care academic hospital. Samples for culture were obtained from HCWs' hands prior to their entering a patient's room, from HCWs' disposable gowns and gloves after they completed patient care activities, and from HCWs' hands immediately after they removed their protective gowns and gloves. RESULTS: Of 137 HCWs caring for patients colonized or infected with MRSA and/or VRE, 24 (17.5%; 95% confidence interval, 11.6%-24.4%) acquired the organism on their gloves, gown, or both. HCW contact with the endotracheal tube or tracheostomy site of a patient (P < .05), HCW contact with the head and/or neck of a patient (P < .05), and HCW presence in the room of a patient with a percutaneous endoscopic gastrostomy and/or jejunostomy tube (P < .05) were associated with an increased risk of acquiring these organisms. CONCLUSIONS: The gloves and gowns of HCWs frequently become contaminated with MRSA and VRE during the routine care of patients, and particularly during care of the patient's respiratory tract and any associated indwelling devices. As part of a larger infection control strategy, including high-compliance hand disinfection, they likely provide a useful barrier to transmitting antibiotic-resistant organisms among patients in an inpatient setting.

Increasing prevalence of gastrointestinal colonization with ceftazidime-resistant gram-negative bacteria among intensive care unit patients.

BACKGROUND: The occurrence of nosocomial infections due to third-generation cephalosporin-resistant gram-negative bacteria is increasing. Gastrointestinal colonization is an important reservoir for antibiotic-resistant bacteria, and it often precedes clinical infection. OBJECTIVE: To estimate the prevalence of gastrointestinal colonization with ceftazidime-resistant gram-negative bacteria among intensive care unit (ICU) patients at a university-affiliated tertiary-care hospital during 2 distinct periods and to assess whether, at any time during the index hospitalization, colonized patients had a clinical culture positive for the same organism that was recovered from surveillance culture. SETTING: Two ICUs at the University of Maryland Medical Center, a 656-bed tertiary-care hospital located in Baltimore, Maryland. Both ICUs provide care to adult patients. METHODS: We performed a cross-sectional study of adult patients admitted to the medical ICU or the surgical ICU from June 14 to July 14, 2003, and from June 14 to July 14, 2006. Perirectal swab samples were obtained for surveillance culture on admission to the intensive care unit, weekly thereafter, and at discharge. Each culture sample was plated onto MacConkey agar supplemented with ceftazidime. RESULTS: In 2003, a total of 33 (18.8%) of 176 patients were colonized with ceftazidime-resistant gram-negative bacilli; in 2006, 60 (31.4%) of 191 patients were (P<.01). This increase was largely driven by an increase in ceftazidime-resistant Klebsiella isolates (which accounted for 6.4% of isolates in 2003 and for 22.8% in 2006; P<.01). In 2003, a total of 16 (48.5%) of 33 colonized patients had a clinical culture positive for the same organism that was recovered from the perirectal surveillance culture, compared with 22 (36.6%) of 60 colonized patients in 2006 (P=.28). CONCLUSION: Our data suggest that gastrointestinal colonization with ceftazidime-resistant gram-negative bacilli is common, that its prevalence is increasing, and that colonization may result in clinical cultures positive for these bacilli.

Risk factors for colonization with extended-spectrum beta-lactamase-producing bacteria and intensive care unit admission.

Extended-spectrum beta-lactamase (ESBL)-producing bacteria are emerging pathogens. To analyze risk factors for colonization with ESBL-producing bacteria at intensive care unit (ICU) admission, we conducted a prospective study of a 3.5-year cohort of patients admitted to medical and surgical ICUs at the University of Maryland Medical Center. Over the study period, admission cultures were obtained from 5,209 patients. Of these, 117 were colonized with ESBL-producing Escherichia coli and Klebsiella spp., and 29 (25%) had a subsequent ESBL-positive clinical culture. Multivariable analysis showed the following to be statistically associated with ESBL colonization at admission: piperacillin-tazobactam (odds ratio [OR] 2.05, 95% confidence interval [CI] 1.36-3.10), vancomycin (OR 2.11, 95% CI 1.34-3.31), age > 60 years (OR 1.79, 95% CI 1.24-2.60), and chronic disease score (OR 1.15; 95% CI 1.04-1.27). Coexisting conditions and previous antimicrobial drug exposure are thus predictive of colonization, and a large percentage of these patients have subsequent positive clinical cultures for ESBL-producing bacteria.

Impact of freezing on the future utility of archived surveillance culture specimens.

The ability to recover bacteria from frozen culture specimens has important implications. The purpose of this study was to validate the utility of frozen specimens for recovery of several gram-positive and gram-negative bacterial species by culture. Results demonstrate that 98% of 250 bacterial isolates identified on initial culture were subsequently recovered by culture of frozen specimens after a median storage period of 564 days.

Identifying groups at high risk for carriage of antibiotic-resistant bacteria.

BACKGROUND: No simple, cost-effective methods exist to identify patients at high risk for methicillin-resistant Staphylococcus aureus and vancomycin-resistant enterococci colonization outside intensive care settings. Without such methods, colonized patients are entering hospitals undetected and transmitting these bacteria to other patients. We aimed to develop a highly sensitive, simple-to-administer prediction rule to identify subpopulations of patients at high risk for colonization on hospital admission. METHODS: We conducted a prospective cohort study of adult patients admitted to the general medical and surgical wards of a tertiary-care facility. Data were collected using electronic medical records and an investigator-administered questionnaire. Cultures of anterior nares and the perirectal area were also collected within 48 hours of admission. RESULTS: Among 699 patients who enrolled in this study, 697 underwent nasal cultures; 555, perirectal cultures; and 553, both. Patient self-report of a hospital admission in the previous year was the most sensitive variable in identifying patients colonized with methicillin-resistant Staphylococcus aureus or with either organism (sensitivity, 76% and 90%, respectively). A prediction rule requiring patients to self-report having received antibiotics and a hospital admission in the previous year would have identified 100% of patients colonized with vancomycin-resistant enterococci. In the high-risk groups defined by the prediction rule, the prevalence of colonization by methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci, or either organism were 8.1%, 10.2%, and 15.0%, respectively. CONCLUSION: Patients with a self-reported previous admission within 1 year may represent a high-risk group for colonization by methicillin-resistant Staphylococcus aureus or vancomycin-resistant enterococci at hospital admission and should be considered for targeted active surveillance culturing.

Methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococci co-colonization.

We assessed the prevalence, risk factors, and clinical outcomes of patients co-colonized with vancomycin-resistant enterococci (VRE) and methicillin-resistant Staphylococcus aureus (MRSA) upon admission to the medical and surgical intensive care units (ICUs) of a tertiary-care facility between January 1, 2002, and December 31, 2003. Co-colonization was defined as a VRE-positive perirectal surveillance culture with an MRSA-positive anterior nares surveillance culture collected concurrently. Among 2,440 patients, 65 (2.7%) were co-colonized. Independent risk factors included age (odds ratio [OR] 1.03, 95% confidence interval [CI] 1.01-1.05), admission to the medical ICU (OR 4.38, 95% CI 2.46-7.81), male sex (OR 1.93, 95% CI 1.14-3.30), and receiving antimicrobial drugs on a previous admission within 1 year (OR 3.06, 95% CI 1.85-5.07). None of the co-colonized patients would have been identified with clinical cultures alone. We report a high prevalence of VRE/MRSA co-colonization upon admission to ICUs at a tertiary-care hospital.