To describe pathogen distribution and antimicrobial resistance patterns for healthcare-associated infections (HAIs) reported to the National Healthcare Safety Network (NHSN) from pediatric locations during 2011–2014.

Device-associated infection data were analyzed for central line-associated bloodstream infection (CLABSI), catheter-associated urinary tract infections (CAUTI), ventilator-associated pneumonia (VAP), and surgical site infection (SSI). Pooled mean percentage resistance was calculated for a variety of pathogen-antimicrobial resistance pattern combinations and was stratified by location for device-associated infections (neonatal intensive care units [NICUs], pediatric intensive care units [PICUs], pediatric oncology and pediatric wards) and by surgery type for SSIs.

From 2011 to 2014, 1,003 hospitals reported 20,390 pediatric HAIs and 22,323 associated pathogens to the NHSN. Among all HAIs, the following pathogens accounted for more than 60% of those reported: Staphylococcus aureus (17%), coagulase-negative staphylococci (17%), Escherichia coli (11%), Klebsiella pneumoniae and/or oxytoca (9%), and Enterococcus faecalis (8%). Among device-associated infections, resistance was generally lower in NICUs than in other locations. For several pathogens, resistance was greater in pediatric wards than in PICUs. The proportion of organisms resistant to carbapenems was low overall but reached approximately 20% for Pseudomonas aeruginosa from CLABSIs and CAUTIs in some locations. Among SSIs, antimicrobial resistance patterns were similar across surgical procedure types for most pathogens.

This report is the first pediatric-specific description of antimicrobial resistance data reported to the NHSN. Reporting of pediatric-specific HAIs and antimicrobial resistance data will help identify priority targets for infection control and antimicrobial stewardship activities in facilities that provide care for children.

Infect Control Hosp Epidemiol 2018;39:1–11

To investigate and control an outbreak of colonization and infection caused by vancomycin-resistant enterococci (VRE) in a burn intensive care unit (BICU).

Epidemiological investigation, including multiple point-prevalence culture surveys of patients and environment, cultures from hands of healthcare workers (HCWs), pulsed-field gel electrophoresis (PFGE) typing of patient and environmental isolates, case-control study, and institution and monitoring of control measures.

BICU in an 800-bed university medical center in Galveston, Texas.

Between June 6, 1996, and July 14, 1997, 21 patients were colonized by VRE, and 4 of these patients developed bacteremia. Of 2,844 environmental cultures, 338 (11.9%) were positive, but all hand cultures from HCWs were negative. PFGE typing indicated that the outbreak was clonal, with VRE isolates from patients differing by ≤4 bands from the index case. Thirteen of 14 environmental isolates varied by ≤4 bands from the pattern of the index case. A case-control study analyzed by exact logistic regression identified diarrhea (odds ratio [OR], 43.9; 95% confidence interval [CI95], 5.5-infinity; P=.0001) and administration of an antacid (OR, 24.2; CI95,2.9-infinity; P=.002) as independent risk factors for acquisition of VRE. During a 5-week period in October and November 1996, all patient and 317 environmental cultures were negative for VRE. The outbreak recurred from a contaminated electrocardiogram lead that had not been identified during the prior 5 weeks. VRE were finally eradicated from the BICU in July 1997, using barrier isolation and a very aggressive environmental decontamination program.

A VRE outbreak in a BICU over 13 months was caused by a single clone. After apparent eradication of VRE from a BICU, recrudescence of the outbreak occurred, evidently from a small inapparent source of environmental contamination. Changes in gastrointestinal (GI) tract function (motility) and administration of medications, other than antibiotics, that have an effect on the GI tract may increase the risk of GI tract colonization by VRE in burn patients. Application of barrier isolation and an aggressive environmental decontamination program can eradicate VRE from a burn population.

Contact precautions are a cornerstone of infection prevention but have also been associated with less healthcare worker (HCW) contact and adverse events. We studied how contact precautions modified HCW behavior in 4 acute care facilities.

Prospective cohort study.

Four acute care facilities in the United States performing active surveillance for methicillin-resistant Staphylococcus aureus.

Trained observers performed “secret shopper” monitoring of HCW activities during routine care, using a standardized collection tool and fixed 1-hour observation periods.

A total of 7,743 HCW visits were observed over 1,989 hours. Patients on contact precautions had 36.4% fewer hourly HCW visits than patients not on contact precautions (2.78 vs 4.37 visits per hour; P< .001 ) as well as 17.7% less direct patient contact time with HCWs (13.98 vs 16.98 minutes per hour; P = .02). Patients on contact precautions tended to have fewer visitors (23.6% fewer; P = .08). HCWs were more likely to perform hand hygiene on exiting the room of a patient on contact precautions (63.2% vs 47.4% in rooms of patients not on contact precautions; P< .001).

Contact precautions were found to be associated with activities likely to reduce transmission of resistant pathogens, such as fewer visits and better hand hygiene at exit, while exposing patients on contact precautions to less HCW contact, less visitor contact, and potentially other unintended outcomes.

The International Nosocomial Infection Control Consortium (INICC) was established in 15 developing countries to reduce infection rates in resource-limited hospitals by focusing on education and feedback of outcome surveillance (infection rates) and process surveillance (adherence to infection control measures). We report a time-sequence analysis of the effectiveness of this approach in reducing rates of central line–associated bloodstream infection (CLABSI) and associated deaths in 86 intensive care units with a minimum of 6-month INICC membership.

Pooled CLABSI rates during the first 3 months (baseline) were compared with rates at 6-month intervals during the first 24 months in 53,719 patients (190,905 central line–days). Process surveillance results at baseline were compared with intervention period data.

During the first 6 months, CLABSI incidence decreased by 33% (from 14.5 to 9.7 CLABSIs per 1,000 central line–days). Over the first 24 months there was a cumulative reduction from baseline of 54% (from 16.0 to 7.4 CLABSIs per 1,000 central line–days; relative risk, 0.46 [95% confidence interval, 0.33–0.63]; P <.001). The number of deaths in patients with CLABSI decreased by 58%. During the intervention period, hand hygiene adherence improved from 50% to 60% (P<.001); the percentage of intensive care units that used maximal sterile barriers at insertion increased from 45% to 85% (P < .001), that adopted Chlorhexidine for antisepsis increased from 7% to 27% (P = .018), and that sought to remove unneeded catheters increased from 37% to 83% (P = .004); and the duration of central line placement decreased from 4.1 to 3.5 days (P < .001).

Education, performance feedback, and outcome and process surveillance of CLABSI rates significantly improved infection control adherence, reducing the CLABSI incidence by 54% and the number of CLABSI-associated deaths by 58% in INICC hospitals during the first 2 years.

Methicillin-resistant Staphylococcus aureus (MRSA) isolates from patients with community-associated infection have been described as strains genetically distinct from the strains isolated from patients with healthcare-associated infection. This study examines the hypothesis that community-associated MRSA (CA-MRSA) strains now cause serious infections in hospitalized patients.

Thirty-seven clinical MRSA isolates were randomly selected from blood isolates obtained from July 2003 through June 2004. Strains were tested for staphylococcal chromosomal cassette mec (SCCmec) type, pulsed-field gel electrophoresis (PFGE) type, and presence of Panton-Valentine leukocidin (PVL) genes. Medical records review and epidemiologic classification was performed by an investigator blinded to the results of the bacterial strain analysis. Episodes of bloodstream infection were independently classified as either community-associated or healthcare-associated infections, and bacterial isolates were independently classified as either CA-MRSA strains or healthcare-associated MRSA (HA-MRSA) strains, according to established definitions.

A tertiary care Veterans Affairs Medical Center.

Twenty-four (65%) of 37 MRSA isolates were SCCmec type IV, a genetic type characteristic of CA-MRSA strains; 22 of these 24 isolates belonged to the CA-MRSA clone USA300 and carried PVL genes. Thirteen (35%) of the 37 strains were SCCmec type II, of which 12 were USA100-ST5 and 12 lacked PVL genes. Thirty patients (81%) had healthcare-associated infections; 18 (60%) of these 30 were infected with isolates carrying markers of CA-MRSA strains. Of 7 patients with CA-MRSA infections, 6 were infected with isolates belonging to the USA300 clone. Patients with healthcare-associated bloodstream infections were as likely to be infected with a CA-MRSA strain as patients with a community-associated infection (P = .38).

MRSA strains with molecular characteristics of CA-MRSA strains have emerged as an important cause of serious health-care-associated infection in our hospital.

To examine the clinical outcomes and costs associated with Staphylococcus aureus bacteremia among hemodialysis-dependent patients.

Prospectively identified cohort study.

A tertiary-care university medical center in North Carolina.

Two hundred ten hemodialysis-dependent adults with end-stage renal disease hospitalized with S. aureus bacteremia.

The majority of the patients (117; 55.7%) underwent dialysis via tunneled catheters, and 29.5% (62) underwent dialysis via synthetic arteriovenous fistulas. Vascular access was the suspected source of bacteremia in 185 patients (88.1%). Complications occurred in 31.0% (65), and the overall 12-week mortality rate was 19.0% (40). The mean cost of treating S. aureus bacteremia, including readmissions and outpatient costs, was $24,034 per episode. The mean initial hospitalization cost was significantly greater for patients with complicated versus uncomplicated S. aureus bacteremia ($32,462 vs $17,011; P= .002).

Interventions to decrease the rate of S. aureus bacteremia are needed in this high-risk, hemodialysis-dependent population (Infect Control Hosp Epidemiol 2005;26:534-539).

To describe the epidemiologic and molecular investigations that successfully contained an outbreak of methicillin-resistant Staphylococcus aureus (MRSA) in a neonatal intensive care unit (NICU).

Isolates of MRSA were typed by pulsed-field gel electrophoresis (PFGE) and S. aureus protein A (spa).

A level III-IV, 45-bed NICU located in a children's hospital within a medical center.

Incident cases had MRSA isolated from clinical cultures (eg, blood) or surveillance cultures (ie, anterior nares).

Infected and colonized infants were placed on contact precautions, cohorted, and treated with mupirocin. Surveillance cultures were performed for healthcare workers (HCWs). Colonized HCWs were treated with topical mupirocin and hexachlorophene showers.

From January to March 2001, the outbreak strain of MRSA PFGE clone B, was harbored by 13 infants. Three (1.3%) of 235 HCWs were colonized with MRSA. Two HCWs, who rotated between the adult and the pediatric facility, harbored clone C. One HCW, who exclusively worked in the children's hospital, was colonized with clone B. From January 1999 to November 2000, 22 patients hospitalized in the adult facility were infected or colonized with clone B. Spa typing and PFGE yielded concordant results. PFGE clone B was identified as spa type 16, associated with outbreaks in Brazil and Hungary.

A possible route of MRSA transmission was elucidated by molecular typing. MRSA appears to have been transferred from our adult facility to our pediatric facility by a rotating HCW. Spa typing allowed comparison of our institution's MRSA strains with previously characterized outbreak clones.

Studies conducted in tertiary care hospitals of different European countries and the United States have shown incidence rates of candidemia ranging from 0.17 to 0.76 and 0.28 to 0.96 per 1,000 admissions, respectively. So far, only 1 study has evaluated the incidence rates of candidemia in tertiary care hospitals in Latin American countries.

To evaluate the epidemiology of candidemia in 4 tertiary care hospitals in São Paulo, Brazil.

Multicenter, laboratory-based surveillance of candidemia.

A total of 7,038 episodes of bloodstream infection were identified, and Candida species accounted for 282 cases (4%). The incidence rate of candidemia was 1.66 candidemic episodes per 1,000 hospital admissions. Candida albicans was the most frequently isolated Candida species in all hospitals, but Candida species other than C. albicans accounted for 62% of isolates, including predominantly Candida parapsilosis and Candida tropicalis. Azole resistance was restricted to only 2% of all Candida isolates (1 isolate of Candida glabrata and 4 isolates of Candida rugosa). Candidemia was mostly documented in surgical patients with long durations of hospital stay. The crude mortality rate was 61%, and advanced age and high Acute Physiology and Chronic Health Evaluation II score were both conditions independently associated with risk of death.

We observed in our series a higher incidence rate of candidemia than that reported in European countries and the United States. Advanced age and a high Acute Physiology and Chronic Health Evaluation II score were factors associated with a higher probability of death in candidemic patients. Fluconazole-resistant Candida strains are still a rare finding in our case-based study of candidemia.

Treatment of Staphylococcus aureus colonization before surgery reduces risk of surgical site infection (SSI). The regimen of nasal mupirocin ointment and topical chlorhexidine gluconate is effective, but cost and patient compliance may be a barrier. Nasal povidone-iodine solution may provide an alternative to mupirocin.

We conducted an investigator-initiated, open-label, randomized trial comparing SSI after arthroplasty or spine fusion in patients receiving topical chlorhexidine wipes in combination with either twice daily application of nasal mupirocin ointment during the 5 days before surgery or 2 applications of povidone-iodine solution into each nostril within 2 hours of surgical incision. The primary study end point was deep SSI within the 3 months after surgery.

In the modified intent-to-treat analysis, a deep SSI developed after 14 of 855 surgical procedures in the mupirocin group and 6 of 842 surgical procedures in the povidone-iodine group (P = .1); S. aureus deep SSI developed after 5 surgical procedures in the mupirocin group and 1 surgical procedure in the povidone-iodine group (P = .2). In the per protocol analysis, S. aureus deep SSI developed in 5 of 763 surgical procedures in the mupirocin group and 0 of 776 surgical procedures in the povidone-iodine group (P = .03).

Nasal povidone-iodine may be considered as an alternative to mupirocin in a multifaceted approach to reduce SSI.

ClinicalTrials.gov identifier: NCT01313182.

To evaluate the epidemiology, outcomes, and importance of Clostridium difficile colonization pressure (CCP) as a risk factor for C. difficile–associated disease (CDAD) acquisition in intensive care unit (ICU) patients.

Secondary analysis of data from a 30-month retrospective cohort study.

A 19-bed medical ICU in a midwestern tertiary care referral center.

Consecutive sample of adult patients with a length of stay of 24 hours or more between July 1, 1997, and December 31, 1999.

Seventy-six (4%) of 1,872 patients were identified with CDAD; 40 (53%) acquired CDAD in the ICU, for an incidence of 3.2 cases per 1,000 patient-days. Antimicrobial therapy, enteral feeding, mechanical ventilation, vancomycin-resistant enterococci (VRE) colonization or infection, and CCP (5.5 vs 2.0 CDAD case-days of exposure for patients with acquired CDAD vs no CDAD; P = .001) were associated with CDAD acquisition in the univariate analysis. Only VRE colonization or infection (45% of patients with acquired CDAD vs 16% of patients without CDAD; adjusted odds ratio, 2.76 [95% confidence interval, 1.36-5.59]) and a CCP of more than 30 case-days of exposure (20% with acquired CDAD vs 2% with no CDAD; adjusted odds ratio, 3.77 [95% confidence interval, 1.14-12.49]) remained statistically significant in the multivariable analysis. Lengths of stay (6.1 vs 3.0 days; P < .001 by univariate analysis) and ICU costs ($11,353 vs $6,028; P < .001 by univariate analysis) were higher for patients with any CDAD than for patients with no CDAD.

In this nonoutbreak setting, the CCP was an independent risk factor for acquisition of CDAD in the ICU at the upper range of exposure duration. Having CDAD in the ICU was a marker of excess healthcare use.

To study the association of antibiotic-utilization measures and control of multidrug-resistant (MDR) Klebsiella pneumoniae after emergence in two hospitals in our medical center.

Rates of MDR K pneumoniae at two hospitals were compared before and after acute interventions, including emphasis on Contact Precautions and education in antibiotic utilization. Antipseudomonal β-lactam antibiotic use was measured before and after the interventions at both hospitals. Pulsed-field gel electrophoresis of whole cell DNA was used as a marker of strain identity.

Clonal strain dissemination was the major mechanism of emergence at hospital A; emergence was polyclonal at hospital B. Antibiotic-utilization interventions at both institutions included physician education regarding the association of ceftazidime use and MDR K pneumoniae. At hospital A, ceftazidime use decreased from 4,301 g in the preintervention period, to 1,248 g in the postintervention period. Piperacillin-tazobactam use increased from 12,455 g to 17,464 g. Ceftazidime resistance in Kpneumoniae decreased from 110 (22%) of 503 isolates to 61 (15%) of 407 isolates (P<.05); piperacillin-tazobactam resistance decreased from 181 (36%) of 503 to 77 (19%) of 407 isolates (P<.05). At hospital B, ceftazidime use decreased from 6,533 g in the preintervention period to 4,792 g in the postintervention period. Piperacillin-tazobactam use increased from 58,691 g to 67,027 g. Ceftazidime resistance in K pneumoniae decreased from 42 (10%) of 415 isolates to 19 (5%) of 383 isolates (P<.05). Piperacillin-tazobactam resistance decreased from 91 (22%) of 415 isolates to 54 (14%) of 383 isolates (P<.05). Follow-up data showed continued decrease in piperacillin-tazobactam resistance despite increased use at both hospitals.

Antibiotic-use measures may be particularly important for control of MDR K pneumoniae, whether emergence is clonal or polyclonal.

To test the evidence that the risk of infection related to central venous catheters (CVCs) is decreased by anti-infective coating or cuffing.

Systematic review of randomized, controlled trials comparing anti-infective with inactive (control) CVCs.

Average insertion times were taken as a measurement of the length of insertion. Dichotomous data were combined using a fixed effect model and expressed as odds ratio (OR) with 95% confidence interval (CI95).

Two trials on antibiotic coating (343 CVCs) had an average insertion time of 6 days; the risk of BSI decreased from 5.1% with control to 0% with anti-infective catheters. There were no trials with longer average insertion times. In three trials on silver collagen cuffs (422 CVCs), the average insertion time ranged from 5 to 8.2 days (median, 7 days); the risk of BSI was 5.6% with control and 3.2% with anti-infective catheters. In another trial on silver collagen cuffs (101 CVCs), the average insertion time was 38 days; the risk of BSI was 3.7% with control and 4.3% with anti-infective catheters. In five trials on chlorhexidine-silver sulfadiazine coating (1,269 CVCs), the average insertion time ranged from 5.2 to 7.5 days (median, 6 days); the risk of BSI decreased from 4.1% with control to 1.9% with anti-infective catheters. In five additional trials on chlorhexidine–silver sulfadiazine coating (1,544 CVCs), the average insertion time ranged from 7.8 to 20 days (median, 12 days); the risk of BSI was 4.5% with control and 4.2% with anti-infective catheters.

Antibiotic and chlorhexidine–silver sulfadiazine coatings are anti-infective for short (approximately 1 week) insertion times. For longer insertion times, there are no data on antibiotic coating, and there is evidence of lack of effect for chlorhexidine-silver sulfadiazine coating. For silver-impregnated collagen cuffs, there is evidence of lack of effect for both short- and long-term insertion.

To determine increased hospital stay and direct costs attributable to hospital-acquired, laboratory-confirmed bloodstream infection (BSI), and to evaluate the matching variable length of stay (LOS).

Retrospective (historical) cohort study with 1:2 matching in intensive care units and surgical wards.

A 2,000-bed university hospital in Rome, Italy.

All patients admitted between January 1994 and June 1995 who had hospital-acquired, laboratory-confirmed BSI were considered cases; all others were eligible as controls.

Two controls (A and B) were selected per case in a stepwise fashion. Controls in group A were selected according to the following six criteria: ward, gender, age, diagnosis, central venous catheter, and LOS equal to the interval from admission to infection in a matched case ± 20% (LOS ± 20%). Controls in group B were selected according to the first five criteria, but excluded LOS ± 20%.

One hundred five of 108 patients were each matched with two controls. The matching appropriateness score was greater than 90%. With the use of controls in groups A and B, the case-fatality rates attributable to hospital-acquired, laboratory-confirmed BSI were 35.2% and 40.9%, respectively; the estimated risk ratios for death were 2.60 and 3.52 (P = .0001), respectively. The increased hospital stay per case attributable to hospital-acquired, laboratory-confirmed BSI was 19.1 (mean) and 13.0 (median) days for matched pairs in control group A and 19.9 (mean) and 15.0 (median) days for matched pairs in control group B. With controls in group A, the cost of increased hospital stay per patient attributable to hospital-acquired, laboratory-confirmed BSI was Euro 15,413. The additional cost per patient due to treatment was Euro 943, making the overall direct cost Euro 16,356 per case.

This study should make it possible to estimate the cost of hospital-acquired, laboratory-confirmed BSI in most hospitals after adjusting for incidence rate. It also confirmed the use of LOS ± 20% as a matching variable to limit overestimation of increased hospital stay. To our knowledge, this is among the first such studies in Europe.

Despite a paucity of evidence, decolonization measures are prescribed for outpatients with recurrent Staphylococcus aureus skin and soft-tissue infection (SSTI).

Compare the effectiveness of 4 regimens for eradicating S. aureus carriage.

Open-label, randomized controlled trial. Colonization status and recurrent SSTI were ascertained at 1 and 4 months.

Barnes-Jewish and St. Louis Children's Hospitals, St. Louis, Missouri, 2007–2009.

Three hundred patients with community-onset SSTI and S. aureus colonization in the nares, axilla, or inguinal folds.

Participants were randomized to receive no therapeutic intervention (control subjects) or one of three 5-day regimens: 2% mupirocin ointment applied to the nares twice daily, intranasal mupirocin plus daily 4% chlorhexidine body washes, or intranasal mupirocin plus daily dilute bleach water baths.

Among 244 participants with 1-month colonization data, modified intention-to-treat analysis revealed S. aureus eradication in 38% of participants in the education only (control) group, 56% of those in the mupirocin group (P = .03 vs controls), 55% of those in the mupirocin and chlorhexidine group (P = .05), and 63% off those in the mupirocin and bleach group (P = .006). Of 229 participants with 4-month colonization data, eradication rates were 48% in the control group, 56% in the mupirocin only group (P = .40 vs controls), 54% in the mupirocin and chlorhexidine group (P = .51), and 71% in the mupirocin and bleach group (P = .02). At 1 and 4 months, recurrent SSTIs were reported by 20% and 36% of participants, respectively.

An inexpensive regimen of dilute bleach baths, intranasal mupirocin, and hygiene education effectively eradicated S. aureus over a 4-month period. High rates of recurrent SSTI suggest that factors other than endogenous colonization are important determinants of infection.

ClinicalTrials.gov identifier: NCT00513799.

To identify risk factors associated with surgical-site infections (SSIs) following cesarean sections.

Prospective cohort study.

High-risk obstetrics and neonatal tertiary-care center in upstate New York.

Population-based sample of 765 patients who underwent cesarean sections at our facility during 6-month periods each year from 1996 through 1998.

Prospective surgical-site surveillance was conducted using methodology of the National Nosocomial Infections Surveillance System. Infections were identified during admission, within 30 days following the cesarean section, by read-mission to the hospital or by a postdischarge survey.

Multiple logistic-regression analysis identified four factors independently associated with an increased risk of SSI following cesarean section: absence of antibiotic prophylaxis (odds ratio [OR], 2.63; 95% confidence interval [CI95], 1.50-4.6; P=.008); surgery time (OR, 1.01; CI95, 1.00-1.02; P=.04); <7 prenatal visits (OR, 3.99; CI95, 1.74-9.15; P=.001); and hours of ruptured membranes (OR, 1.02; CI95,1.01-1.03; P=.04).

Patients given antibiotic prophylaxis had significantly lower infection rates than patients who did not receive antibiotic prophylaxis (F=02), whether or not active labor or ruptured membranes were present.

Among the variables identified as risk factors for SSI, only two have the possibility to be changed through interventions. Antibiotic prophylaxis would benefit all cesarean patients regardless of active labor or ruptured membranes and would decrease morbidity and length of stay. Women's healthcare professionals also must continue to encourage pregnant women to start prenatal visits early in the pregnancy and to maintain scheduled visits throughout the pregnancy to prevent perinatal complications, including postoperative infection.

To identify risk factors for infection with imipenem-resistant Pseudomonas aeruginosa and determine the impact of imipenem resistance on clinical and economic outcomes among patients infected with P. aeruginosa.

An ecologic study, a case-control study, and a retrospective cohort study.

A 625-bed tertiary care medical center.

All patients who had an inpatient clinical culture positive for P. aeruginosa between January 1, 1999, and December 31, 2000.

From 1991 through 2000, the annual prevalence of imipenem resistance among P. aeruginosa isolates increased significantly (P<.001 by the χ2 test for trend). Among 879 patients infected with P. aeruginosa during 1999-2000, a total of 142 had imipenem-resistant P. aeruginosa infection (the case group), whereas 737 had imipenem-susceptible P. aeruginosa infection (the control group). The only independent risk factor for imipenem-resistant P. aeruginosa infection was prior fluoroquinolone use (adjusted odds ratio, 2.52 [95% confidence interval {CI}, 1.61-3.92]; P<.001). Compared with patients infected with imipenem-susceptible P. aeruginosa, patients infected with imipenem-resistant P. aeruginosa had longer subsequent hospitalization durations (15.5 days vs 9 days; P = .02) and greater hospital costs ($81,330 vs $48,381; P<.001). The mortality rate among patients infected with imipenem-resistant P. aeruginosa was 31.1%, compared with 16.7% for patients infected with imipenem-susceptible P. aeruginosa (relative risk, 1.86 [95% CI, 1.38-2.51]; P<.001). In multivariable analyses, there remained an independent association between infection with imipenem-resistant P. aeruginosa and mortality.

The prevalence of imipenem resistance among P. aeruginosa strains has increased markedly in recent years and has had a significant impact on both clinical and economic outcomes. Our results suggest that curtailing use of other antibiotics (particularly fluoroquinolones) may be important in attempts to curb further emergence of imipenem resistance.