To determine whether the seasonality of surgical site infections (SSIs) can be explained by changes in temperature.

Retrospective cohort analysis.

The National Inpatient Sample database.

All hospital discharges with a primary diagnosis of SSI from 1998 to 2011 were considered cases. Discharges with a primary or secondary diagnoses of specific surgeries commonly associated with SSIs from the previous and current month served as our “at risk” cohort.

We modeled the national monthly count of SSI cases both nationally and stratified by region, sex, age, and type of institution. We used data from the National Climatic Data Center to estimate the monthly average temperatures for all hospital locations. We modeled the odds of having a primary diagnosis of SSI as a function of demographics, payer, location, patient severity, admission month, year, and the average temperature in the month of admission.

SSI incidence is highly seasonal, with the highest SSI incidence in August and the lowest in January. During the study period, there were 26.5% more cases in August than in January (95% CI, 23.3–29.7). Controlling for demographic and hospital-level characteristics, the odds of a primary SSI admission increased by roughly 2.1% per 2.8°C (5°F) increase in the average monthly temperature. Specifically, the highest temperature group, >32.2°C (>90°F), was associated with an increase in the odds of an SSI admission of 28.9% (95% CI, 20.2–38.3) compared to temperatures <4.4°C (<40°F).

At population level, SSI risk is highly seasonal and is associated with warmer weather.

Infect Control Hosp Epidemiol 2017;38:809–816

To describe the epidemiology of hospital-acquired infections (HAIs) in veterans with spinal cord injury and disorder (SCI&D).

Retrospective medical record review.

Midwestern Department of Veterans Affairs spinal cord injury center.

A total of 226 patients with SCI&D hospitalized at least once during a 2-year period (October 1, 2001, through September 30, 2003).

A total of 549 hospitalizations were included in the analysis (mean duration of hospitalization, 33.7 days); an HAI occurred during 182 (33.2%) of these hospitalizations. A total of 657 HAIs occurred during 18,517 patient-days in the hospital (incidence rate, 35.5 HAIs per 1,000 patient-days). Almost half of the 226 patients had at least 1 HAI; the mean number of HAIs among these patients was 6.0 HAIs per patient. The most common HAIs were urinary tract infection (164 [25.0%] of the 657 HAIs; incidence rate, 8.9 cases per 1,000 patient-days), bloodstream infection (111 [16.9%]; incidence rate, 6.0 cases per 1,000 patient-days), and bone and joint infection (103 [15.7%]; incidence rate, 5.6 cases per 1,000 patient-days). The most common culture isolates were gram-positive bacteria (1,082 [45.6%] of 2,307 isolates), including Staphylococcus aureus, and gram-negative bacteria (1,033 [43.6%] of isolates), including Pseudomonas aeruginosa. Multivariate regression demonstrated that predictors of HAI were longer length of hospital stay (P = .002), community-acquired infection (P = .007), and use of a urinary invasive device (P = .01) or respiratory invasive device (P = .04).

The overall incidence of HAIs in persons with SCI&D was higher than that reported for other populations, confirming the increased risk of HAI in persons with spinal cord injury. The increased risk associated with longer length of stay and with community-acquired infection suggests that strategies are needed to reduce the duration of hospitalization and to effectively treat community-acquired infection, to decrease infection rates. There is significant room for improvement in reducing the incidence of HAIs in this population.

The primary objective was to determine the rate of and risk factors for nosocomial primary bloodstream infection (BSI) in pediatric intensive care unit (PICU) patients in order to determine the validity of our previously published findings. The secondary objective was to analyze whether risk factors for primary BSI differed by organism type, particularly whether device use was more strongly associated with BSI due to gram-positive organisms.

Prospective cohort study.

St. Louis Children's Hospital, a 235-bed academic tertiary care center with a 28-bed combined medical and surgical PICU.

PICU patients admitted between September 1, 1999, and September 1, 2001.

Nosocomial primary BSIs.

Of 2,310 patients, 55% were male, and 73% were white. There were 124 episodes of primary BSI in 87 patients (3.8%). Coagulase-negative Staphylococcus organisms were the leading cause of BSI (42 of 124 episodes). The rate of BSI was 9 BSIs/1,000 central venous catheter–days. Multiple logistic regression analysis showed that independent predictors of nosocomial primary BSI included higher number of arterial catheter–days (adjusted odds ratio [aOR], 5.7 per day of arterial catheterization; 95% confidence interval [CI], 3.4-9.8), higher number of packed red blood cell transfusions (aOR, 1.2; 95% CI, 1.1-1.4), and genetic syndrome (aOR, 4.7; 95% CI, 1.8-12). Severity of illness, underlying illnesses, and medications were not independently associated with increased risk of nosocomial BSI.

Arterial catheter use and packed red blood cell transfusion are potentially modifiable risk factors for nosocomial primary BSI in PICU patients. Genetic syndromes may be markers for unrecognized immune defects that impair host defense against microorganisms.

To describe common pathogens and antimicrobial resistance patterns for healthcare-associated infections (HAIs) among pediatric patients that occurred in 2015–2017 and were reported to the Centers for Disease Control and Prevention’s National Healthcare Safety Network (NHSN).

Antimicrobial resistance data were analyzed for pathogens implicated in central line-associated bloodstream infections (CLABSIs), catheter-associated urinary tract infections (CAUTIs), ventilator-associated pneumonias (VAPs), and surgical site infections (SSIs). This analysis was restricted to device-associated HAIs reported from pediatric patient care locations and SSIs among patients <18 years old. Percentages of pathogens with nonsusceptibility (%NS) to selected antimicrobials were calculated by HAI type, location type, and surgical category.

Overall, 2,545 facilities performed surveillance of pediatric HAIs in the NHSN during this period. Staphylococcus aureus (15%), Escherichia coli (12%), and coagulase-negative staphylococci (12%) were the 3 most commonly reported pathogens associated with pediatric HAIs. Pathogens and the %NS varied by HAI type, location type, and/or surgical category. Among CLABSIs, the %NS was generally lowest in neonatal intensive care units and highest in pediatric oncology units. Staphylococcus spp were particularly common among orthopedic, neurosurgical, and cardiac SSIs; however, E. coli was more common in abdominal SSIs. Overall, antimicrobial nonsusceptibility was less prevalent in pediatric HAIs than in adult HAIs.

This report provides an updated national summary of pathogen distributions and antimicrobial resistance patterns among pediatric HAIs. These data highlight the need for continued antimicrobial resistance tracking among pediatric patients and should encourage the pediatric healthcare community to use such data when establishing policies for infection prevention and antimicrobial stewardship.

To reduce inappropriate antimicrobial prescribing across ambulatory care, understanding the patient-, provider-, and practice-level characteristics associated with antibiotic prescribing is essential. In this study, we aimed to elucidate factors associated with inappropriate antimicrobial prescribing across urgent care, family medicine, and pediatric and internal medicine ambulatory practices.

Data for this retrospective cohort study were collected from outpatient visits for common upper respiratory conditions that should not require antibiotics. The cohort included 448,990 visits between January 2014 and May 2016. Carolinas HealthCare System urgent care, family medicine, internal medicine and pediatric practices were included across 898 providers and 246 practices.

Prescribing rates were reported per 1,000 visits. Indications were defined using the International Classification of Disease, Ninth and Tenth Revisions, Clinical Modification (ICD-9/10-CM) criteria. In multivariable models, the risk of receiving an antibiotic prescription was reported with adjustment for practice, provider, and patient characteristics.

The overall prescribing rate in the study cohort was 407 per 1,000 visits (95% confidence interval [CI], 405–408). After adjustment, adult patients seen by an advanced practice practitioner were 15% more likely to receive an antimicrobial than those seen by a physician provider (incident risk ratio [IRR], 1.15; 95% CI, 1.03–1.29). In the pediatric sample, older providers were 4 times more likely to prescribe an antimicrobial than providers aged ≤30 years (IRR, 4.21; 95% CI, 2.96–5.97).

Our results suggest that patient, practice, and provider characteristics are associated with inappropriate antimicrobial prescribing. Future research should target antibiotic stewardship programs to specific patient and provider populations to reduce inappropriate prescribing compared to a “one size fits all” approach.

Infect Control Hosp Epidemiol 2018;39:307–315

To evaluate the prevalence and risk factors of nasal Staphylococcus aureus (SA) in the community.

Cross-sectional study.

Wake Forest University, Winston-Salem, North Carolina.

Four hundred fifty students were screened for nasal SA carriage during the fall of 2000, 2001, and 2002.

Students were screened by nose swabs. A self-administered questionnaire collected information on demographics and medical history. Antibiotic testing and PFGE were performed on isolates. Risk factors were determined by logistic regression analysis.

Of 450 volunteers, 131 (29%) were SA carriers. Antibiotic resistance was high for azithromycin (26%) and low for ciprofloxacin (1%), tetracycline (5%), mupirocin (1%), and methicillin (2%). PFGE patterns were not associated with carriage. Age, male gender, white race, medical student, allergen injection therapy, chronic sinusitis, rheumatoid arthritis, hospitalization for 6 months or less, and use of antibiotics were associated with carrier status by univariate analysis. Stepwise multivariate logistic regression led to a best fitting model with older age (OR, 1.04; CI95, 1.005-1.079), male gender (OR, 1.50; CI95, 0.982-2.296), and chronic sinusitis (OR, 2.71; CI95, 0.897-8.195) as risk factors. Antibiotic use (< 4 weeks) (OR, 0.41; CI95, 0.152-1.095) and allergen injection therapy (OR 0.41; CI95, 0.133-1.238) were protective. Analyses of carriers revealed candidate factors for persistent carriage to be nasal SA colonization rate and male gender. Factors for azithromycin resistance were non-medical students and antibiotic use in the past 6 months.

Older male volunteers suffering from chronic sinusitis and not taking antibiotics were at higher risk for carrying SA.

TO evaluate whether a hybrid electronic screening algorithm using a total joint replacement (TJR) registry, electronic surgical site infection (SSI) screening, and electronic health record (EHR) review of SSI is sensitive and specific for SSI detection and reduces chart review volume for SSI surveillance.

Validation study.

A large health maintenance organization (HMO) with 8.6 million members.

Using codes for infection, wound complications, cellullitis, procedures related to infections, and surgeon-reported complications from the International Classification of Diseases, Ninth Revision, Clinical Modification, we screened each TJR procedure performed in our HMO between January 2006 and December 2008 for possible infections. Flagged charts were reviewed by clinical-content experts to confirm SSIs. SSIs identified by the electronic screening algorithm were compared with SSIs identified by the traditional indirect surveillance methodology currently employed in our HMO. Positive predictive values (PPVs), negative predictive values (NPVs), and specificity and sensitivity values were calculated. Absolute reduction of chart review volume was evaluated.

The algorithm identified 4,001 possible SSIs (9.5%) for the 42,173 procedures performed for our TJR patient population. A total of 440 case patients (1.04%) had SSIs (PPV, 11.0%; NPV, 100.0%). The sensitivity and specificity of the overall algorithm were 97.8% and 91.5%, respectively.

An electronic screening algorithm combined with an electronic health record review of flagged cases can be used as a valid source for TJR SSI surveillance. The algorithm successfully reduced the volume of chart review for surveillance by 90.5%.

Mycobacterium simiae is found primarily in the southwestern United States, Israel, and Cuba, with tap water as its suspected reservoir. Our institution saw an increase in M. simiae isolates in 2001. An investigation into possible contaminated water sources was undertaken.

Environmental cultures were performed from water taps in the microbiology laboratory, patient rooms, points in the flow of water to the hospital, and patients' homes. Patient and environmental M. simiae were compared by PFGE.

Military treatment facility in San Antonio, Texas.

All patients with cultures positive for M. simiae between January 2001 and April 2002. Medical records were reviewed.

M. simiae was recovered from water samples from the hospital, patients' home showers, and a well supplying the hospital. A single PFGE clone was predominant among water isolates (9 of 10) and available patient isolates (14 of 19). There was an association between exposure to hospital water and pulmonary samples positive for the clonal M. simiae strain (P = .0018). Only 3 of 22 culture-positive patients met criteria for M. simiae pulmonary disease. Of them, two had indistinguishable M. simiae strains from tap water to which they were routinely exposed.

This represents an outbreak of M. simiae colonization with one nosocomial infection. It is only the second time that M. simiae has been recovered from hospital tap water and its first presentation in municipal water. This study raises issues about the need and feasibility of eliminating or avoiding exposure to M. simiae from tap water.

The coronavirus disease 2019 (COVID-19) pandemic has induced a reinforcement of infection control measures in the hospital setting. Here, we assess the impact of the COVID-19 pandemic on the incidence of nosocomial Clostridioides difficile infection (CDI).

We retrospectively compared the incidence density (cases per 10,000 patient days) of healthcare-facility–associated (HCFA) CDI in a tertiary-care hospital in Madrid, Spain, during the maximum incidence of COVID-19 (March 11 to May 11, 2020) with the same period of the previous year (control period). We also assessed the aggregate in-hospital antibiotic use (ie, defined daily doses [DDD] per 100 occupied bed days [BD]) and incidence density (ie, movements per 1,000 patient days) of patient mobility during both periods.

In total, 2,337 patients with reverse transcription-polymerase chain reaction–confirmed COVID-19 were admitted to the hospital during the COVID-19 period. Also, 12 HCFA CDI cases were reported at this time (incidence density, 2.68 per 10,000 patient days), whereas 34 HCFA CDI cases were identified during the control period (incidence density, 8.54 per 10,000 patient days) (P = .000257). Antibiotic consumption was slightly higher during the COVID-19 period (89.73 DDD per 100 BD) than during the control period (79.16 DDD per 100 BD). The incidence density of patient movements was 587.61 per 1,000 patient days during the control period and was significantly lower during the COVID-19 period (300.86 per 1,000 patient days) (P < .0001).

The observed reduction of ~70% in the incidence density of HCFA CDI in a context of no reduction in antibiotic use supports the importance of reducing nosocomial transmission by healthcare workers and asymptomatic colonized patients, reinforcing cleaning procedures and reducing patient mobility in the epidemiological control of CDI.

Varicella-zoster virus (VZV) vaccine is recommended to protect susceptible healthcare workers (HCWs) from serious disease and to prevent nosocomial spread of VZV. We evaluated clinical outcomes and serological responses in HCWs after immunization with live attenuated VZV vaccine.

Vaccinees were immunized from 1979 to 1998 during VZV vaccine trials, as well as after licensure, and followed prospectively for 1 month to 20.6 (mean 4.6) years after vaccination. Sera were tested by fluorescent antibody to membrane antigen (FAMA), latex agglutination (LA), and enzyme-linked immunoassay (EIA) to detect VZV-specific antibodies.

The median age of the 120 HCWs was 26 years; 51 (42%) were males.

Ninety eight (82%) of these study subjects received vaccine prepared by Merck and 22 (18%) by SmithKline Beecham; 25, 81, and 14 vaccinees received one dose, two doses, and three doses, respectively.

The crude attack rate was 10%; 12 of 120 HCWs developed chickenpox 6 months to 8.4 years after vaccination. The attack rates following household and hospital exposures were 18% (4/22) and 8% (6/72), respectively. All resulting illness was mild to moderate (mean 40 vesicles). Seroconversion after vaccination was documented by FAMA in 96% of HCWs, although 31% lost detectable antibodies. Compared with FAMA, LA and EIA were 82% and 74% sensitive and 94% and 89% specific, respectively.

The VZV vaccine effectively protected HCWs from varicella, particularly from serious disease. Currently available serological tests are not optimal, and improved assays are needed.

To compare the accuracy of surveillance of severe sepsis using electronic health record clinical data vs claims and to compare incidence and mortality trends using both methods.

We created an electronic health record–based surveillance definition for severe sepsis using clinical indicators of infection (blood culture and antibiotic orders) and concurrent organ dysfunction (vasopressors, mechanical ventilation, and/or abnormal laboratory values). We reviewed 1,000 randomly selected medical charts to characterize the definition’s accuracy and stability over time compared with a claims-based definition requiring infection and organ dysfunction codes. We compared incidence and mortality trends from 2003–2012 using both methods.

Two US academic hospitals.

Adult inpatients.

The electronic health record–based clinical surveillance definition had stable and high sensitivity over time (77% in 2003–2009 vs 80% in 2012, P=.58) whereas the sensitivity of claims increased (52% in 2003–2009 vs 67% in 2012, P=.02). Positive predictive values for claims and clinical surveillance definitions were comparable (55% vs 53%, P=.65) and stable over time. From 2003 to 2012, severe sepsis incidence imputed from claims rose by 72% (95% CI, 57%–88%) and absolute mortality declined by 5.4% (95% CI, 4.6%–6.7%). In contrast, incidence using the clinical surveillance definition increased by 7.7% (95% CI, −1.1% to 17%) and mortality declined by 1.7% (95% CI, 1.1%–2.3%).

Sepsis surveillance using clinical data is more sensitive and more stable over time compared with claims and can be done electronically. This may enable more reliable estimates of sepsis burden and trends.

Infect. Control Hosp. Epidemiol. 2016;37(2):163–171

The Centers for Disease Control and Prevention has published a new guideline on hand hygiene promoting the use of the alcohol-based handrub, but the technique was not addressed. The goal of this study was to evaluate the influence of technique on the efficacy of the alcohol-based handrub.

Healthcare workers (HCWs) attending a course in hospital epidemiology.

A fluorescent dye was added to a hand antiseptic, and hands were checked under ultraviolet light after antiseptic cleansing. Data regarding the numbers of predefined fluorescent areas on the skin were collected in addition to demographic data such as age, gender, job description, and job experience. Results of the visualization test were compared with the data from microbiological samples before and after the procedure by the hand plate technique.

Sixty HCWs were tested, 63% of whom had worked in infection control for more than 10 years. Sixty-six percent of all participants still had detectable bacteria after antisepsis. The mean log10 CFU reduction was 2.0 (range, 0–3.85). Twenty-five percent of all HCWs achieved less than 1.1 log10 CFU. Staphylococcus aureus was isolated from 13% (one of them being methicillin resistant) and gram-negative bacilli from 6.7%. After using the alcohol handrub, one subject still remained positive for S. aureus. Years of experience was the single most important factor predicting antimicrobial efficacy.

Technique is of crucial importance in hand antisepsis. Major deficiencies were detected among even highly trained HCWs. Training should be provided before switching from handwashing to the alcohol handrub.

Disinfection and sterilization are critical components of infection control. Unfortunately, breaches of disinfection and sterilization guidelines are not uncommon.

To describe a method for evaluating a potential breach of guidelines for high-level disinfection and sterilization of medical devices.

The appropriate scientific literature was reviewed to determine the frequency of failures of compliance. A risk assessment model was constructed.

A 14-step protocol was constructed to aid infection control professionals in the evaluation of potential disinfection and sterilization failures. In addition, a model is presented for aiding in determining how patients should be notified of the potential adverse event. Sample statements and letters are provided for communicating with the public and individual patients.

Use of a protocol can guide an institution in managing potential disinfection and sterilization failures.

To detect an outbreak-related source of Legionella, control the outbreak, and prevent additional Legionella infections from occurring.

Epidemiologic investigation of an acute outbreak of hospital-associated Legionnaires disease among outpatients and visitors to a Wisconsin hospital.

Patients with laboratory-confirmed Legionnaires disease who resided in southeastern Wisconsin and had illness onsets during February and March 2010.

Patients with Legionnaires disease were interviewed using a hypothesis-generating questionnaire. On-site investigation included sampling of water and other potential environmental sources for Legionella testing. Case-finding measures included extensive notification of individuals potentially exposed at the hospital and alerts to area healthcare and laboratory personnel.

Laboratory-confirmed Legionnaires disease was diagnosed in 8 patients, all of whom were present at the same hospital during the 10 days prior to their illness onsets. Six patients had known exposure to a water wall-type decorative fountain near the main hospital entrance. Although the decorative fountain underwent routine cleaning and maintenance, high counts of Legionella pneumophila serogroup 1 were isolated from cultures of a foam material found above the fountain trough.

This outbreak of Legionnaires disease was associated with exposure to a decorative fountain located in a hospital public area. Routine cleaning and maintenance of fountains does not eliminate the risk of bacterial contamination. Our findings highlight the need to evaluate the safety of water fountains installed in any area of a healthcare facility.

Infect Control Hosp Epidemiol 2012;33(2):185-191

To examine the impact of introduction of an alcohol-based hand rub on hand hygiene knowledge and compliance and hand colonization of healthcare workers (HCWs) in a long-term-care facility (LTCF).

Two floors of an LTCF participated. Ward A used the hand rub as an adjunct to soap and water; ward B was the control. HCWs' hands were cultured using the bag-broth technique for Staphylococcus aureus, gram-negative bacilli (GNB), Candida, and vancomycin-resistant enterococci (VRE). HCWs completed a questionnaire at baseline and after an educational intervention and introduction of rub.

Hand hygiene practices, knowledge, and opinions did not change after the educational or rub intervention. Ward A HCWs thought that the rub was faster (P = .002) and less drying (P = .04) than soap. Hand hygiene frequency did not differ at baseline between the two floors, but increased on ward A by the end of the study (P = .04). HCWs were colonized frequently with GNB (66%), Candida (41%), S. aureus (20%), and VRE (9%). Although colonization did not change from baseline on either ward, the rub was more effective in clearing GNB (P = .03) and S. aureus (P = .003). Nosocomial infection rates did not change.

The alcohol-based hand rub was a faster, more convenient, less drying method of hand hygiene for HCWs in an LTCF, and it improved compliance. Although microbial colonization did not change, the rub was more efficacious in removing pathogens already present on the hands of HCWs.