Antianaerobic antibiotic therapy promotes persistent high-density growth of vancomycin-resistant enterococci (VRE) in the stool of colonized patients. We tested the hypothesis that antibiotic regimens with potent antianaerobic activity promote overgrowth of coexisting antibiotic-resistant, gram-negative bacilli in the stool of VRE-colonized patients.

Eight-month prospective study examining the effect of antibiotic therapy on the stool density of gram-negative bacilli resistant to ceftazidime, ciprofloxacin, or piperacillin/tazobactam.

A Department of Veterans Affairs medical center including an acute care hospital and nursing home.

All VRE-colonized patients with at least 3 stool samples available for analysis.

One-hundred forty stool samples were obtained from 37 study patients. Forty-nine (61%) of 80 stool samples obtained during therapy with an antianaerobic regimen were positive for an antibiotic-resistant, gram-negative bacillus, whereas only 14 (23%) of 60 samples obtained 4 or more weeks after completion of such therapy were positive (P < .001). Twenty-four (65%) of the 37 patients had one or more stool cultures positive for a gram-negative bacillus resistant to ciprofloxacin, ceftazidime, or piperacillin/tazobactam. The density of these organisms was higher during therapy with antianaerobic regimens than in the absence of such therapy for at least 2 weeks (mean ± standard deviation, 5.6 ± 1.4 and 3.9 ± 0.71 log10 organisms/g; P < .001).

Limiting the use of antianaerobic antibiotics in VRE-colonized patients may reduce the density of colonization with coexisting antibiotic-resistant, gram-negative bacilli.

In treating orthopedic infections, the long-term impact of vancomycin therapy on colonization by methicillin-resistant Staphylococcus aureus (MRSA) and the emergence of vancomycin-intermediate S. aureus is unknown.

Prospective surveillance of the effect of long-term vancomycin therapy on colonization by MRSA and the emergence of vancomycin-intermediate S. aureus.

Thirty-four patients with MRSA osteomyelitis that was microbiologically documented were longitudinally observed for the emergence of vancomycin-intermediate S. aureus at 3 body sites (wound, anterior nares, and groin) during the initial period of vancomycin therapy and at the 2-month follow-up. Twenty patients received the standard dose (20 mg/kg/d) for 34 ± 6 days and 14 patients received a high dose (40 mg/kg/d) of vancomycin for 37 ± 9 days.

During vancomycin treatment, global MRSA carriage (all body sites) fell from 100% to 25% in the group of patients receiving the standard dose of vancomycin, and from 100% to 40% in the group receiving the high dose. During the 2-month follow-up period after vancomycin therapy, global MRSA carriage increased from 25% to 55% in the group receiving the standard dose and decreased from 43% to 36% in the group receiving the high dose.

Therapy with a high dose of vancomycin contributes to the sustained eradication of MRSA carriage without promoting the emergence of glycopeptide resistance.

To identify institution-specific risk factors for MRSA bacteremia and develop an objective mechanism to estimate the probability of methicillin resistance in a given patient with Staphylococcus aureus bacteremia (SAB).

A cohort study was performed to identify institution-specific risk factors for MRSA. Logistic regression was used to model the likelihood of MRSA A stepwise approach was employed to derive a parsimonious model. The MRSA prediction tool was developed from the final model.

A 279-bed, level 1 trauma center.

Between January 1, 1999, and June 30, 2001, 494 patients with clinically significant episodes of SAB were identified.

The MRSA rate was 45.5%. Of 18 characteristics included in the logistic regression, the only independent features for MRSA were prior antibiotic exposure (OR, 9.2; CI95, 4.8 to 17.9), hospital onset (OR, 3.0; CI95, 1.9 to 4.9), history of hospitalization (OR, 2.5; CI95, 1.5 to 3.8), and presence of decubitus ulcers (OR, 2.5; CI95, 1.2 to 4.9). The prediction tool was derived from the final model, which was shown to accurately reflect the actual MRSA distribution in the cohort.

Through multivariate modeling techniques, we were able to identify the most important determinants of MRSA at our institution and develop a tool to predict the probability of methicillin resistance in a patient with SAB. This knowledge can be used to guide empiric antibiotic selection. In the era of antibiotic resistance, such tools are essential to prevent indiscriminate antibiotic use and preserve the longevity of current antimicrobials.

To study multicenter antibiotic practices for suspected early-onset sepsis (EOS) with negative blood cultures (NegBCs) and to identify opportunities for reduction of antimicrobial exposure.

Retrospective study.

Thirty academic hospitals (University HealthSystem Consortium) located in 24 states.

Data were from a survey of 790 extremely low birth weight (ELBW) infants. Total antibiotic exposures (antibiotic-days per patient) were calculated.

On admission to the NICU, 94% of 790 ELBW infants had BCs performed and empiric antibiotics initiated. When PosBC and NegBC infants were compared, 47 patients with PosBCs were similar to 695 with NegBCs in birth weight, gestational age (GA), and mortality. Patients with suspected EOS but NegBCs given ampicillin/aminoglycosides were grouped by length of administration and GA. For GA of 26 weeks or younger, 170 infants given a short (≤ 3 days) and 157 given a long (≥ 7 days) course were similar regarding birth weight, mortality, antepartum history, and CRIB scores, but were different (P < .01) in number receiving a third antimicrobial (3% and 17%) and antibiotic-days (23 and 38). For GA of 27 weeks or older, 113 infants given a short and 77 given a long course differed (P < .01) in number receiving a third antimicrobial (2% and 23%) and antibiotic-days (19 and 30).

Most suspected EOS infants with NegBCs are given antibiotics, but no antepartum historical risk factors or neonatal clinical signs explained prolonged administration. Discontinuing empiric antibiotics when BCs are negative in asymptomatic ELBW infants can reduce antimicrobial exposure without compromising clinical outcome.

To describe the epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) at a university hospital in Tenerife, Canary Islands, during a 40-month period and to evaluate the effectiveness of the application of control measures.

Laboratory-based surveillance, medical charts and microbiological records review, and characterization of strains by pulsed-field gel electrophoresis (PFGE) were used to describe the epidemiology. Infection control practices were introduced as an intervention.

A 650-bed, tertiary-care university hospital.

Patients with clinical and nasal isolates of MRSA and colonized staff members.

The rate of nosocomial MRSA infections was 32.5% for 1997, 17.9% for 1998, 14.5% for 1999, and 25.6% during the first 4 months of 2000. The major sites of isolation for nosocomial MRSA infection included surgical wounds (25%) and the lower respiratory tract (24%). Intensive care units and surgical specialties had more frequent MRSA cases. Characteristics associated with nosocomial MRSA isolates included prior use of intensive antibiotic therapy, prolonged hospital stays, major underlying illness, invasive procedures, and older age. PFGE type A (subtype A1) was the strain most frequently found and the only PFGE type involved in clusters.

Surveillance cultures and contact droplet precautions were followed by decreased rates for 2 years. Nevertheless, the spread of PFGE subtype Al to many different areas of the hospital and the increase in incidence during the first third of 2000 indicates either that surveillance cultures were not used widely enough or that compliance with isolation measures was suboptimal.

To determine the added costs of hygienic measures (barrier precautions, isolation, and decontamination) required for MRSA carriers in German hospitals and possible strategies for cost reduction.

On a septic surgical ward caring for 35% of all MRSA cases in a university hospital (1,182 beds), additional costs for personnel time and materials were calculated and medical charts of all MRSA cases admitted to the ward during 1 year were analyzed retrospectively. Twelve of the ward's 13 beds were located in rooms with at least 2 beds.

Four hundred ninety-eight MRSA carrier hospital-days (of 20 MRSA cases) could be assessed. All patients (80% men, 50% older than 74.5 years) had broken skin.

In 95% of the cases, microbiological findings suggested transmission of MRSA during the current or a previous stay on this ward. The study found total avoidable costs of approximately 142,794.01 euros in 1 year, averaging 371.95 euros for one MRSA patient hospital-day and 9,261.56 euros per MRSA case. The most expensive single measure was blocked beds in multibed rooms (305.75 euros/day), which accounted for 82% of the extra costs. Costs most likely were underestimated.

Daily additional case costs amounted to 96% of social security payments. Blocked beds in multibed rooms accounted for more than 80% of these excess costs. Isolation has been scientifically validated and is required by law in Germany. Building an adequate number of single-bed rooms should help prevent spread and would greatly lower the added costs of infection.

The benefit of screening healthcare workers (HCWs) at risk for methicillin-resistant Staphylococcus aureus (MRSA) carriage and furloughing MRSA-positive HCWs to prevent spread to patients is controversial. We evaluated our MRSA program for HCWs between 1992 and 2002.

A university medical center in the Netherlands, where methicillin resistance has been kept below 0.5% of all nosocomial S. aureus infections using active surveillance cultures and isolation of colonized patients.

HCWs caring for MRSA-positive patients or patients in foreign hospitals were screened for MRSA. MRSA-positive HCWs had additional cultures, temporary exclusion from patient-related work, assessment of risk factors for persisting carriage, decolonization therapy with mupirocin intranasally and chlorhexidine baths for skin and hair, and follow-up cultures.

Fifty-nine HCWs were colonized with MRSA. Seven of 840 screened employees contracted MRSA in foreign hospitals; 36 acquired MRSA after contact with MRSA-positive patients despite isolation precautions (attack rate per outbreak varied from less than 1% to 15%). Our hospital experienced 17 MRSA outbreaks, including 13 episodes in which HCWs were involved. HCWs were index cases of at least 4 outbreaks. In 8 outbreaks, HCWs acquired MRSA after caring for MRSA-positive patients despite isolation precautions.

Postexposure screening of HCWs allowed early detection of MRSA carriage and prevention of subsequent transmission to patients. Where the MRSA prevalence is higher, the role of HCWs may be greater. In such settings, an adapted version of our program could help prevent dissemination.

To investigate the rates of Staphylococcus aureus carriage on the hands and in the noses of healthcare workers (HCWs) and the relatedness of S. aureus isolates found in the two sites.

Point-prevalence study.

Department for Thoracic and Cardiovascular Surgery at the University Hospital of Uppsala, Uppsala, Sweden.

Samples were obtained from 133 individuals, 18 men and 115 women, using imprints of each hand on blood agar and a swab from the nose. S. aureus isolates were identified by standard methods and typed by pulsed-field gel electrophoresis.

S. aureus was found on the hands of 16.7% of the men and 9.6% of the women, and in the noses of 33.3% of the men and 17.4% of the women. The risk ratio for S. aureus carriage on the hands with nasal carriage was 7.4 (95% confidence interval, 2.7 to 20.2; P < .001). Among the 14 HCWs carrying S. aureus on their hands, strain likeness to the nasal isolate was documented for 7 (50%).

Half of the HCWs acquired S. aureus on the hands from patients or the environment and half did so by apparent self-inoculation from the nose. Regardless of the source of contamination, good compliance with hand hygiene is needed from all HCWs to protect patients from nosocomial infections. The moderate rate of S. aureus carriage on hands in this setting could be the result of the routine use of alcoholic hand antisepsis.

Because patients with vancomycin-resistant Enterococcus bacteremia (VREB) usually have a higher severity of illness, it has been unclear whether VREB is worse than vancomycin-susceptible Enterococcus bacteremia (VSEB).

Data on morbidity and case fatality rates and costs were pooled from studies comparing VREB and VSEB, identified by Medline (January 1986 to April 2002) and meeting abstracts. Heterogeneity across studies was assessed with contingency table chi-square. Multivariate analyses (MVAs) controlling for other predictors were evaluated.

Thirteen studies compared case-fatality rates of VREB and VSEB. VREB case fatality was significantly higher (48.9% vs 19%; RR, 2.57; CI95, 2.27 to 2.91; attributable mortality = 30%). Five studies compared VREB with VSEB when bacteremia was the direct cause of death; VREB case fatality was significantly higher (39.1% vs 21.8%; RR, 1.79; CI95, 1.28 to 2.5; attributable mortality = 17%). Four MVAs found significant increases in case-fatality rates (OR 2.10 to 4.0), 3 showed trends toward increase (OR, 1.74 to 3.34 with wide confidence intervals), and 3 with low statistical power found no difference. VREB recurred in 16.9% versus 3.7% with VSEB (P < .0001). Three studies reported significant increases in LOS, costs, or both with VREB.

Most studies have had inadequate sample size, inadequate adjustment for other predictors of adverse outcomes, or both, but available data suggest that VREB is associated with higher recurrence, mortality, and excess costs than VSEB including multiple studies adjusting for severity of illness.

To evaluate the impact of an interventional multidisciplinary antibiotic management program on expenditures for antibiotics and on the incidence of nosocomial infections caused by Clostridium difficile and antibiotic-resistant pathogens during 7 years.

Prospective study with comparison with preintervention trends.

University-affiliated teaching hospital.

All adult inpatients.

A multidisciplinary antibiotic management program to minimize the inappropriate use of third-generation cephalosporins was implemented in 1991. Its impact was evaluated prospectively. The incidence of nosocomial C. difficile and resistant Enterobacteriaceae infections as well as the rate of vancomycin-resistant enterococci (VRE) and methicillin-resistant Staphylococcus aureus (MRSA) were compared with those of National Nosocomial Infections Surveillance System hospitals of similar size.

Following implementation of the program, there was a 22% decrease in the use of parenteral broad-spectrum antibiotics (P < .0001) despite a 15% increase in acuity of patient care during the following 7 years. Concomitantly, there was a significant (P= .002) decrease in nosocomial infections caused by C. difficile and a significant (P = .02) decrease in nosocomial infections caused by resistant Enterobacteriaceae. The program also appeared to have a favorable impact on VRE rates without a sustained impact on MRSA rates.

These results suggest that an ongoing multidisciplinary antibiotic management program may have a sustained beneficial impact on both expenditures for antibiotics and the incidence of nosocomial infection by C. difficile and resistant bacterial pathogens.

To investigate and describe an outbreak of Burkholderia cepacia in a neonatal intensive care unit (NICU) and a pediatric intensive care unit (PICU), and to report the interventions leading to the cessation of the outbreak.

We conducted an epidemiologic investigation of an outbreak of B. cepacia colonization or infection in two clinical wards during a 35-month period (December 1998 to October 2001).

A 500-bed, university hospital-affiliated, tertiary-care pediatric institution in Paris, France, with a 22-bed PICU and 31-bed NICU.

Ribotyping was used to determine the genotypes of B. cepacia isolates. Procedures for the maintenance and disinfection of respiratory therapy devices were reviewed.

Thirty-two children were colonized (n = 14) or infected (n = 18) by B. cepacia in 2 wards (28 in the PICU and 4 in the NICU). In the PICU, a single ribotype was found among the isolates obtained from all of the patients except 1, and from the 6 isolates obtained from respiratory therapy devices (ie, heated humidifier water). In the NICU, the isolates obtained from the patients harbored a single ribotype unrelated to that of the epidemic strain isolated in the PICU; no environmental source of infection was found.

Two different outbreaks appeared to be associated with 2 ribotypes, 1 of which was linked to patient-to-patient transmission via respiratory therapy devices. Complete elimination of the outbreak was achieved only when disposable, sterilizable, or easy-to-disinfect materials were used in the PICU. The source of infection in the NICU was not found.