Natalia Blanco

Effect of meteorological factors and geographic location on methicillin-resistant Staphylococcus aureus and vancomycin-resistant enterococci colonization in the US

Background Little is known about the effect of meteorological conditions and geographical location on bacterial colonization rates particularly of antibiotic-resistant Gram-positive bacteria. We aimed to evaluate the effect of season, meteorological factors, and geographic location on methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE) colonization. Methods The prospective cohort included all adults admitted to 20 geographically-dispersed ICUs across the US from September 1, 2011 to October 4, 2012. Nasal and perianal swabs were collected at admission and tested for MRSA and VRE colonization respectively. Poisson regression models using monthly aggregated colonization counts as the outcome and mean temperature, relative humidity, total precipitation, season, and/or latitude as predictors were constructed for each pathogen. Results A total of 24,704 ICU-admitted patients were tested for MRSA and 24,468 for VRE. On admission, 10% of patients were colonized with MRSA and 12% with VRE. For MRSA and VRE, a 10% increase in relative humidity was associated with approximately a 9% increase in prevalence rate. Southerly latitudes in the US were associated with higher MRSA colonization, while northerly latitudes were associated with higher VRE colonization. In contrast to MRSA, the association between VRE colonization and latitude was observed only after adjusting for relative humidity, which demonstrates how this effect is highly driven by this meteorological factor. Conclusions To our knowledge, we are the first to study the effect of meteorological factors and geographical location/latitude on MRSA and VRE colonization in adults. Increasing humidity was associated with greater MRSA and VRE colonization. Southerly latitudes in the US were associated with greater MRSA and less VRE. The effect of these factors on MRSA and VRE rates has the potential not only to inform patient management and treatment, but also infection prevention interventions.

Clostridium difficile shows no trade-off between toxin and spore production within the human host

Purpose. This study aimed to describe the correlation between Clostridium difficile spore and toxin levels within the human host. In addition, we assessed whether overgrowth of Candida albicans modified this association. Methodology. We measured toxin, spore and Candida albicans levels among 200 successively collected stool samples that tested positive for C. difficile, and PCR ribotyped these C. difficile isolates. Analysis of variance and linear regression were used to test the association between spore and toxin levels. Kruskal‐Wallis tests and t‐tests were used to compare the association between spore or toxin levels and host, specimen, or pathogen characteristics. Results. C. difficile toxin and spore levels were positively associated (P<0.001); this association did not vary significantly with C. albicans overgrowth [≥5 logs of C. albicans colony‐forming units (c.f.u.) g−1]. However, ribotypes 027 and 078–126 were significantly associated with higher levels of toxin and spores, and C. albicans overgrowth. Conclusion. The strong positive association observed between in vivo levels of C. difficile toxin and spores suggests that patients with more severe C. difficile infections may have increased spore production, enhancing C. difficile transmission. Although, on average, spore levels were higher in toxin‐positive samples than in toxin‐negative/PCR‐positive samples, spores were found in almost all toxin‐negative samples. The ubiquity of spore production among toxin‐negative and formed stool samples emphasizes the importance of following infection prevention and control measures for all C. difficile‐positive patients during their entire hospital stay.

Laxative Use in the Setting of Positive Testing for Clostridium difficile Infection

diarrhea in long-term care facilities: what you get is not what you see. Infect Control Hosp Epidemiol 2008;29:760–763. 3. Guerrero DM, Nerandzic MM, Jury LA, Chang S, Jump RL, Donskey CJ. Clostridium difficile infection in a Department of Veterans Affairs long-term care facility. Infect Control Hosp Epidemiol 2011;32:513–515. 4. Mylotte JM, Russell S, Sackett B, Vallone M, Antalek M. Surveillance for Clostridium difficile infection in community nursing homes. J Am Geriatr Soc 2013;61:122–125. 5. Brown KA, Jones M, Daneman N, et al. Importation, antibiotics, and Clostridium difficile infection in veteran long-term care: a multilevel case-control study. Ann Intern Med 2016;164:787–794.

Electronic clostridium difficile infection bundle reduces time to initiation of contact precautions

The impact of computerized order-entry bundles on timing of contact precaution initiation for C. difficile infection (CDI) remains largely unexplored. Implementation of an electronic CDI prevention and management bundle that included an automatic isolation component significantly reduced time to initiation of contact precautions from 33.7 to 22.4 hours. Infect Control Hosp Epidemiol 2016;242-244.

Transmission of resistant Gram-negative bacteria to healthcare personnel gowns and gloves during care of residents in community-based nursing facilities

OBJECTIVE To estimate the risk of transmission of antibiotic-resistant Gram-negative bacteria (RGNB) to gowns and gloves worn by healthcare personnel (HCP) when providing care to residents of community-based nursing facilities to identify the types of care and resident characteristics associated with transmission. DESIGN Prospective observational study.Settings and participantsResidents and HCP from 13 community-based nursing facilities in Maryland and Michigan. METHODS Perianal swabs were collected from residents and cultured to detect RGNB. HCP wore gowns and gloves during usual care activities, and at the end of each interaction, these were swabbed in a standardized manner. Transmission of RGNB from a colonized resident to gowns and gloves was estimated. Odds ratios (ORs) of transmission associated with type of care or resident characteristic were calculated. RESULTS We enrolled 403 residents and their HCP in this study. Overall, 19% of enrolled residents with a perianal swab (n=399) were colonized with at least 1 RGNB. RGNB transmission to either gloves or gowns occurred during 11% of the 584 interactions. Showering the resident, hygiene or toilet assistance, and wound dressing changes were associated with a high risk of transmission. Glucose monitoring and assistance with feeding or medication were associated with a low risk of transmission. Residents with a pressure ulcer were 3 times more likely to transmit RGNB than residents without one (OR, 3.3; 95% confidence interval [CI], 1.0-11.1). CONCLUSIONS Gown and glove use in community nursing facilities should be prioritized for certain residents and care interactions that are deemed a high risk for transmission.

An in silico evaluation of treatment regimens for recurrent Clostridium difficile infection

Background Clostridium difficile infection (CDI) is a significant nosocomial infection worldwide, that recurs in as many as 35% of infections. Risk of CDI recurrence varies by ribotype, which also vary in sporulation and germination rates. Whether sporulation/germination mediate risk of recurrence and effectiveness of treatment of recurring CDI remains unclear. We aim to assess the role of sporulation/germination patterns on risk of recurrence, and the relative effectiveness of the recommended tapered/pulsing regimens using an in silico model. Methods We created a compartmental in-host mathematical model of CDI, composed of vegetative cells, toxins, and spores, to explore whether sporulation and germination have an impact on recurrence rates. We also simulated the effectiveness of three tapered/pulsed vancomycin regimens by ribotype. Results Simulations underscored the importance of sporulation/germination patterns in determining pathogenicity and transmission. All recommended regimens for recurring CDI tested were effective in reducing risk of an additional recurrence. Most modified regimens were still effective even after reducing the duration or dosage of vancomycin. However, the effectiveness of treatment varied by ribotype. Conclusion Current CDI vancomycin regimen for treating recurrent cases should be studied further to better balance associated risks and benefits.

Indirect Versus Direct Standardization Methods for Reporting Healthcare-Associated Infections: An Analysis of Central Line–Associated Bloodstream Infections in Maryland

Whether healthcare-associated infection data should be presented using indirect (current CMS/CDC methodology) or direct standardization remains controversial. We applied both methods to central-line-associated bloodstream infection data from 45 acute-care hospitals in Maryland from 2012 to 2014. We found that the 2 methods generate different hospital rankings with payment implications. Infect Control Hosp Epidemiol 2017;38:989-992.