To identify predictors of treatment for urinary tract infections (UTI) among patients undergoing total hip (THA) or knee (TKA) arthroplasties and to assess an intervention based on these predictors.

We conducted a retrospective cohort study of 200 consecutive patients undergoing THA/TKA between February 21, 2011, and June 30, 2011, to identify predictors of treatment for UTI and a prospective cohort study of 50 patients undergoing these procedures between May 21, 2012, and July 17, 2012, to assess the association of signs or symptoms and UTI treatment. We then conducted a before-and-after study to assess whether implementing an intervention affected the frequency of treatment for UTI before or after THA/TKA.

The orthopedics department of a university health center.

Patients undergoing THA or TKA.

Surgeons revised their UTI screening and treatment practices.

Positive leukocyte esterase (P<.0001; P<.0001) and urine white blood cell count>5 (P=.01; P=.01) were associated with preoperative or postoperative UTI treatment. In the prospective study, 12 patients (24%) had signs and symptoms consistent with UTI. The number of patients treated for presumed UTI decreased 80.2% after the surgeons changed their practices, and surgical site infection (SSI) rates, including prosthetic joint infections (PJIs), did not increase.

Urine leukocyte esterase and white blood cell count were the strongest predictors of treatment for UTI before or after THA/TKA. The intervention was associated with a significant decrease in treatment for UTI, and SSI/PJI rates did not increase.

Infect Control Hosp Epidemiol 2017;38:281–286

To identify risk factors for surgical site infections (SSIs) after spine operations.

Case-control study of SSIs among patients undergoing spine operations.

An academic health center.

We studied patients undergoing spinal fusions or laminectomies at the University of Iowa Hospitals and Clinics from January 1, 2007, through June 30, 2009. We included patients who acquired SSIs meeting the National Healthcare Safety Network definition. We randomly selected controls among patients who had spine operations during the study period and did not meet the SSI definition.

In total, 54 patients acquired SSIs after 2,309 spine operations (2.3 per 100 procedures). SSIs were identified a median of 20 days after spinal fusions and 17 days after laminectomies; 90.7% were identified after discharge and 72.2% were deep incisional or organ-space infections. Staphylococcus aureus caused 53.7% of SSIs. Of patients with SSIs, 64.9% (fusion) and 70.6% (laminectomy) were readmitted and 59.5% (fusion) and 64.7% (laminectomy) underwent reoperation. By multivariable analysis, increased body mass index, Surgical Department A, fusion of 4–8 vertebrae, and operation at a thoracic or lumbar/sacral level were significant risk factors for SSIs after spinal fusions. Lack of private insurance and hypertension were significant risk factors for SSIs after laminectomies. Surgeons from Department A were more likely to use nafcillin or vancomycin for perioperative prophylaxis and to do more multilevel fusions than surgeons from Department B.

SSIs after spine operations significantly increase utilization of healthcare resources. Possible remediable risk factors include obesity, hypertension, and perioperative antimicrobial prophylaxis.

Infect Control Hosp Epidemiol 2016;1458–1467

To determine the epidemiology and relatedness of Clostridium difficile isolates in two geographically separated hospitals in a large metropolitan area, each with unique patients and personnel.

Observational descriptive molecular epidemiology of clinical C. difficile isolates.

Two tertiary-care hospitals in Chicago.

Consecutive C. difficile isolates from the clinical laboratory of a Veterans Affairs hospital during a 13-month period were typed by restriction endonuclease analysis (REA). During an overlapping 3-month period, stool specimens that tested positive for C. difficile toxin from patients at a nearby county hospital were cultured and the recovered isolates typed by the same method.

Nineteen (68%) of 28 nosocomial isolates at the smaller, Veterans Affairs hospital belonged to REA group K. Within this group of closely related strains, 9 distinct REA types were recognized. Twenty-one (72%) of 29 nosocomial isolates at the larger, county hospital also belonged to group K. However, the predominant REA types within group K differed markedly at each institution.

These findings demonstrate a high degree of similarity among nosocomial C. difficile strains from different hospitals in the same city and suggest the possibility of an extended outbreak of a prototype group K strain with subsequent genetic drift at the two different institutions.

To determine whether patients who were colonized or infected with methicillin-resistant Staphylococcus aureus (MRSA) persistently carried the same strain and to identify the extent of strain variation within a population of patients.

Molecular typing by pulsed-field gel electrophoresis (PFGE) of stored MRSA isolates.

A Veterans Administration Medical Center with 288 hospital, 45 intermediate-care, and 75 extended-care beds.

Between January 1991 and March 1993, 91 patients had MRSA identified in routine cultures. One hundred isolates from 57 patients (63%) were available for typing.

Before 1988, only occasional MRSA isolates were identified. By 1993, 50% of S. aureus isolates from unique patients were resistant to methicillin. PFGE identified 7 MRSA strains, 3 of which were identified in specimens from 1 patient each. The most common strains were SD4 (20 patients), SD1 (12 patients), SD2 (12 patients), and SD5a (5 patients). Twenty patients had 2 or more isolates obtained at least 1 week apart (mean, 30.7 weeks; range, 1 to 102 weeks). Of these patients, 12 were colonized or infected with only one strain (mean time observed, 25.1 weeks; range, 1 to 82 weeks). Eight patients had at least 2 different strains (mean time observed, 39 weeks; range, 2 to 102 weeks).

Numerous MRSA strains circulated in tiiis endemic setting; 40% of patients observed over time were colonized or infected witii more than one strain. Molecular typing was an essential tool for evaluating the epidemiology of MRSA in this setting.