Faculty Bibliography

BACKGROUND:The multicenter, cluster-randomized Strategies to Reduce Transmission of Antimicrobial Resistant Bacteria in Intensive Care Units (STAR*ICU) trial was performed in 18 U.S. adult intensive care units (ICUs). It evaluated the effectiveness of infection control strategies to reduce the transmission of methicillin-resistant Staphylococcus aureus (MRSA) colonization and/or infection. Our study objective was to examine the molecular epidemiology of MRSA and assess the prevalence and risk factors for community acquired (CA)-MRSA genotype nasal carriage at the time of ICU admission. METHODS:Selected MRSA isolates were subjected to molecular typing using pulsed-field gel electrophoresis. RESULTS:Of 5,512 ICU patient admissions in the STAR*ICU trial during the intervention period, 626 (11%) had a nares sample culture result that was positive for MRSA. A total of 210 (34%) of 626 available isolates were selected for molecular typing by weighted random sampling. Of 210 patients, 123 (59%) were male; mean age was 63 years. Molecular typing revealed that 147 isolates (70%) were the USA100 clone, 26 (12%) were USA300, 12 (6%) were USA500, 8 (4%) were USA800, and 17 (8%) were other MRSA genotypes. In a multivariate analysis, patients who were colonized with a CA-MRSA genotype (USA300, USA400, or USA1000) were less likely to have been hospitalized during the previous 12 months (PR [prevalence ratio], 0.39 [95% confidence interval (CI), 0.21-0.73]) and were less likely to be older (PR, 0.97 [95% CI, 0.95-0.98] per year) compared with patients who were colonized with a healthcare-associated (HA)-MRSA genotype. CONCLUSION/CONCLUSIONS:CA-MRSA genotypes have emerged as a cause of MRSA nares colonization among patients admitted to adult ICUs in the United States. During the study period (2006), the predominant site of CA-MRSA genotype acquisition appeared to be in the community.

BACKGROUND:Intensive care units (ICUs) are high-risk settings for the transmission of methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococcus (VRE). METHODS:In a cluster-randomized trial, we evaluated the effect of surveillance for MRSA and VRE colonization and of the expanded use of barrier precautions (intervention) as compared with existing practice (control) on the incidence of MRSA or VRE colonization or infection in adult ICUs. Surveillance cultures were obtained from patients in all participating ICUs; the results were reported only to ICUs assigned to the intervention. In intervention ICUs, patients who were colonized or infected with MRSA or VRE were assigned to care with contact precautions; all the other patients were assigned to care with universal gloving until their discharge or until surveillance cultures obtained at admission were reported to be negative. RESULTS:During a 6-month intervention period, there were 5434 admissions to 10 intervention ICUs, and 3705 admissions to 8 control ICUs. Patients who were colonized or infected with MRSA or VRE were assigned to barrier precautions more frequently in intervention ICUs than in control ICUs (a median of 92% of ICU days with either contact precautions or universal gloving [51% with contact precautions and 43% with universal gloving] in intervention ICUs vs. a median of 38% of ICU days with contact precautions in control ICUs, P<0.001). In intervention ICUs, health care providers used clean gloves, gowns, and hand hygiene less frequently than required for contacts with patients assigned to barrier precautions; when contact precautions were specified, gloves were used for a median of 82% of contacts, gowns for 77% of contacts, and hand hygiene after 69% of contacts, and when universal gloving was specified, gloves were used for a median of 72% of contacts and hand hygiene after 62% of contacts. The mean (±SE) ICU-level incidence of events of colonization or infection with MRSA or VRE per 1000 patient-days at risk, adjusted for baseline incidence, did not differ significantly between the intervention and control ICUs (40.4±3.3 and 35.6±3.7 in the two groups, respectively; P=0.35). CONCLUSIONS:The intervention was not effective in reducing the transmission of MRSA or VRE, although the use of barrier precautions by providers was less than what was required. (Funded by the National Institute of Allergy and Infectious Diseases and others; STAR*ICU ClinicalTrials.gov number, NCT00100386.).

A greater prevalence of human immunodeficiency virus (HIV)-infected individuals aged >50 years is projected. This epidemiologic trend will continue to increase as a result of not only greater survival rates among HIV-infected patients who receive treatment, but also of delayed recognition of older individuals with occult HIV disease. Historically, it was thought that, despite viral responses to highly active antiretroviral therapy (HAART) among older individuals that approximate those of younger individuals, older persons infected with HIV could not mount as vigorous an immune response as do younger HIV-infected individuals. However, recent evidence suggests that older HIV-infected individuals may do just as well, because they may be more compliant with their antiretroviral regimens. Limited data are available on the safety and tolerability of HAART in this population. Emerging evidence suggests that metabolic, neuropsychiatric, and cardiovascular morbidities could be exacerbated by use of antiretrovirals or by HIV infection itself. Additional research is needed to optimize the care of older HIV-infected patients.

To investigate the efficacy and tolerability of using lopinavir/ritonavir concurrently with a third protease inhibitor (PI), the authors reviewed the medical records of 47 HIV-infected patients treated with antiretroviral regimens containing lopinavir/ritonavir and amprenavir, saquinavir, indinavir, or nelfinavir. The baseline mean HIV RNA level was 4.6 log(10) copies/mL, and the median CD4 cell count was 123/mm3. By week 40, one patient (2%) was lost to follow-up, and 21 (44%) discontinued their lopinavir/ritonavir plus a third PI regimens: 4 (8%) due to virologic failure as determined by the clinician; 13 (28%) due to toxicity; and 4 (8%) due to social reasons. By intent-to-treat analysis, 12 (26%) of 47 patients had an HIV RNA level of less than 400 copies/mL at 40 weeks. By multivariate analysis, factors associated with virologic response were no prior lopinavir exposure (p =.03) and no prior exposure to nonnucleoside reverse transcriptase inhibitors among patients taking a nonnucleoside reverse transcriptase inhibitor (p =.05). Some HIV-infected patients concurrently treated with lopinavir/ritonavir and a third PI have viral suppression; many eventually discontinue therapy because of toxicity or virologic failure.

A pregnant woman from Nantucket Island, MA was diagnosed with human granulocytic ehrlichiosis at 34 weeks gestation. We describe the diagnostic and therapeutic dilemmas involved and discuss the risks of perinatal transmission.