Prevalence of methicillin-resistant Staphylococcus aureus and Acinetobacter baumannii in a long-term acute care facility

Effects of Staphylococcus aureus on stem cells and potential targeted treatment of inflammatory disorders

Due to the advanced studies on stem cells in developmental biology, the roles of stem cells in the body and their phenotypes in related diseases have not been covered clearly. Meanwhile, with the intensive research on the mechanisms of stem cells in regulating various diseases, stem cell therapy is increasingly being attention because of its effectiveness and safety. As one of the most widely used stem cell in stem cell therapies, hematopoietic stem cell transplantation shows huge advantage in treatment of leukemia and other blood-malignant diseases. Besides, due to the effect of anti-inflammatory and immunomodulatory, mesenchymal stem cells could be a potential therapeutic strategy for variety infectious diseases. In this review, we summarized the effects of Staphylococcus aureus (S. aureus) and its components on different types of adult stem cells and their downstream signaling pathways. Also, we reviewed the roles of different kinds of stem cells in various disease models caused by S. aureus, providing new insights for applying stem cell therapy to treat infectious diseases.

Competitive inhibition and mutualistic growth in co-infections: deciphering Staphylococcus aureus-Acinetobacter baumannii interaction dynamics

Staphylococcus aureus (Sa) and Acinetobacter baumannii (Ab) are frequently co-isolated from polymicrobial infections that are severe and refractory to therapy. Here, we apply a combination of wet-lab experiments and in silico modeling to unveil the intricate nature of the Ab/Sa interaction using both, representative laboratory strains and strains co-isolated from clinical samples. This comprehensive methodology allowed uncovering Sa's capability to exert a partial interference on Ab by the expression of phenol-soluble modulins. In addition, we observed a cross-feeding mechanism by which Sa supports the growth of Ab by providing acetoin as an alternative carbon source. This study is the first to dissect the Ab/Sa interaction dynamics wherein competitive and cooperative strategies can intertwine. Through our findings, we illuminate the ecological mechanisms supporting their coexistence in the context of polymicrobial infections. Our research not only enriches our understanding but also opens doors to potential therapeutic avenues in managing these challenging infections.

Outpatient Clonal Propagation and Rapid Regional Establishment of an Emergent Carbapenem-Resistant Acinetobacter baumannnii Lineage Sequence Type 499Pas

Eliminating carbapenem-resistant Acinetobacter baumannii (CRAb) disease requires comprehensive knowledge of how this noncommensal organism propagates among at-risk hosts. We molecularly characterized an ongoing surge of CRAb cases among patients in a Midwest US healthcare system, which coincided with sustained reductions in hospital-acquired CRAb infections and falloffs of cases associated with distinctly more resistant antibiotypes. Genome sequencing revealed surge isolates belonged to an emergent Pasteur scheme sequence type 499 and comprised multiple contemporaneous clonal clusters. Detailed query of health records revealed no consistent hospital source but instead identified various outpatient healthcare settings linked to cluster cases. We show that CRAb can rapidly establish a regional presence even without gains in breadth of antibiotic resistance and negligible contribution from sustained intrahospital transmission. As CRAb lineages may sidestep control efforts via outpatient epidemiological niches, our approach can be implemented to investigate outpatient CRAb propagation and inform subsequent local surveillance outside hospital settings.

Impact of the Antimicrobial Stewardship Mandate on Multidrug-Resistant Organisms and Clostridioides difficile Infection Among Long-term Care Facility Residents

Objective To determine whether the long-term care facility (LTCF) Centers for Medicare & Medicaid Services (CMS) Antimicrobial Stewardship (AMS) mandate was associated with a change in the combined rate of LTCF-acquired multidrug-resistant organism infection or colonization (MDRO-I/C) and Clostridioides difficile infection (CDI). Design Retrospective quasi-experimental study. Setting A 233-bed community hospital. Participants LTCF residents 75 years of age and older with MDRO-I/C or CDI admitted to the hospital before the AMS mandate in 2015 through 2016 or after the mandate in 2018 through 2019. Intervention LTCF CMS AMS mandate. Main Outcomes Measures Rates of LTCF-acquired MDRO-I/C and CDI. MDRO-I/C were defined by a culture positive for methicillin-resistant Staphylococcus aureus or extended-spectrum beta-lactamase-producing Enterobacterales. CDI was defined by a positive test for C. difficile using a multistep algorithm of toxin, glutamate dehydrogenase, and nucleic acid amplification tests. These specimens must have been collected within 48 hours of hospital admission. Results There were 33 residents with either LTCF-acquired MDRO-I/C or CDI out of a total of 205 hospitalized residents with MDRO-I/C or CDI in 2015 and 2016, resulting in a rate of 16.10%. In comparison, there were 38 residents with either LTCF-acquired MDRO-I/C or CDI out of a total of 253 hospitalized residents with MDRO-I/C or CDI in 2018 and 2019 resulting in a rate of 15.02%. The difference in the combined rate of LTCF-acquired MDRO-I/C and CDI was -1.08% (P = 0.75). Conclusion The AMS mandate was not associated with a significant change in the combined rate of LTCF-acquired MDRO-I/C and CDI, suggesting a need for more robust AMS programs in LTCFs.

Containment of a carbapenem-resistant Acinetobacter baumannii complex outbreak in a COVID-19 intensive care unit

Background

A carbapenem-resistant Acinetobacter baumannii outbreak in the COVID intensive care unit of a community hospital was contained using multidrug resistant organism guidelines. The purpose of this study is to report on an outbreak investigation and containment strategy that was used, and to discuss prevention strategy.

Methods

A multidisciplinary approach contained the spread of infection. Strategies implemented included consultation with experts, screening, and reversal of personal protective equipment conservation. Ensuring infection control best practices are maintained remain important efforts to reduce the spread of multidrug resistant organisms.

Results

Five patients with carbapenem-resistant Acinetobacter baumannii were identified from routine clinical cultures within one week and one patient was identified from active surveillance cultures.

Discussion

Personal protective equipment conservation, strategies to prevent health care personnel exposure, and patient surge staffing protocols may have increased the likelihood of multidrug resistant organism transmission. Environmental and behavioral infection control regulations with effective administrative guidance, active surveillance cultures, and antimicrobial stewardship are critical to prevent future outbreaks.

Conclusions

After outbreak containment strategies were implemented, no additional patients were identified with carbapenem-resistant Acinetobacter baumannii. Conventional infection prevention and control strategies were re-instituted. A multidisciplinary approach with continued focus on hand hygiene, environmental cleaning, and correct use of personal protective equipment needs to be put in place to successfully contain and prevent the spread of carbapenem resistant infections.

Multidrug-Resistant Gram-Negative Bacteria: Infection Prevention and Control Update

Multidrug-resistant gram-negative bacteria (MDR-GNB) pose one of the greatest challenges to health care today because of their propensity for human-to-human transmission and lack of therapeutic options. Containing the spread of MDR-GNB is challenging, and the application of multifaceted infection control bundles during an evolving outbreak makes it difficult to measure the relative impact of each measure. This article will review the utility of various infection control measures in containing the spread of various MDR-GNB and will provide the supporting evidence for these interventions.

Prevalence and Risk Factors for Multidrug-Resistant Organisms Colonization in Long-Term Care Facilities Around the World: A Review

Elderly people confined to chronic care facilities face an increased risk of acquiring infections by multidrug-resistant organisms (MDROs). This review presents the current knowledge of the prevalence and risk factors for colonization by MDROs in long-term care facilities (LTCF), thereby providing a useful reference to establish objectives for implementing successful antimicrobial stewardship programs (ASPs). We searched in PubMed and Scopus for studies examining the prevalence of MDROs and/or risk factors for the acquisition of MDROs in LTCF. One hundred and thirty-four studies published from 1987 to 2020 were included. The prevalence of MDROs in LTCF varies between the different continents, where Asia reported the highest prevalence of extended-spectrum ß-lactamase (ESBL) Enterobacterales (71.6%), carbapenem resistant (CR) Enterobacterales (6.9%) and methicillin-resistant Staphylococcus aureus (MRSA) (25.6%) and North America the highest prevalence to MDR Pseudomonas aeruginosa (5.4%), MDR Acinetobacter baumannii (15.0%), vancomycin-resistant Enterococcus spp. (VRE) (4.0%), and Clostridioides difficile (26.1%). Furthermore, MDRO prevalence has experienced changes over time, with increases in MDR P. aeruginosa and extended spectrum ß-lactamase producing Enterobacterales observed starting in 2015 and decreases of CR Enterobacterales, MDR A. baumannii, VRE, MRSA and C. difficile. Several risk factors have been found, such as male sex, chronic wounds, the use of medical devices, and previous antibiotic use. The last of these aspects represents one of the most important modifiable factors for reducing colonization with MDROs through implementing ASPs in LTCF.

Prevalence of Acb and non-Acb complex in elderly population with urinary tract infection (UTI)

Background: To assess the prevalence of Acinetobacter calcoaceticus-baumannii complex [Acb complex] and non-Acb strains from the urine samples of elderly population with urinary tract infection (UTI) by both phenotypic and genotypic (PCR) characterisation methods from India.Methods: A longitudinal cohort study on 1000 elderly population with UTI was performed for a period of 1 year. Using standard microbiological guidelines, the urine samples were cultured and the Acb and non-Acb complex were identified by standard biochemical characterisation tests. DNA was extracted from all the phenons of the complex for further confirmation by PCR. The amplicons were sequenced for the phylogenetic analysis and clonal identification by comparative genomic assessments.Results and conclusions: Study population yielded 8.5% of Acb and non-Acb-complex with other gram-negative pathogens ranging from 1 to 49.3%. Males were highly affected with the complex under the age group of 70-90. Statistics of the demographic data within the groups showed significant results of the prevalence of Acb and non-Acb complex towards the age group selected and with other associated co-morbidities recorded (at p < 0.05). Chi² statistics for the goodness of fit was significance for genotypic confirmation of the complex.Conclusions: The present investigation documents the prevalence of the Acb and non-Acb complex among the elderly population and suggests the implementation of phenotypic and molecular strategies to assess the correct prevalence rate of the same for surveillance which will also aid in the effective clinical management of UTI by Acb and non-Acb-complex in elderly population.

TOOTHBRUSH AND TOWEL HANDLING AND THEIR MICROBIAL QUALITY: THE CASE OF STUDENTS OF UNIVERSITY FOR DEVELOPMENT STUDIES, NYANKPALA CAMPUS, GHANA

BACKGROUND

Good toothbrush and towel handling are important considerations in personal hygiene. Thus, this study sought to assess how students of the University for Development Studies handle their toothbrushes and towels and the consequence of that with regards to the microbial quality of these personnel hygiene materials.

MATERIALS AND METHODS

A total of 100 swap samples were collected (50 toothbrushes and 50 towels) for microbial analysis. Questionnaires were administered to students from whom samples were collected to ascertain information on how they handle toothbrushes and towels. MacConkey agar and Mannitol Salt agar were used to isolate E. coli and S. aureus respectively, and cefoxitin used to identify the methicillin-resistant S. aureus strains.

RESULTS

E. coli was present in all sampled towels, while 98% of the sampled toothbrushes contained E. coli. It was found that 2% of the respondents kept their toothbrushes in bathhouses, 44% kept them unenclosed in rooms and 54% kept them enclosed in rooms (54%). Also, 48% of the respondents washed their towels once a week, 24% washed once every two weeks, 20% once every month and 8% once a trimester. Moreover, 52% dried their towels in rooms while 48% dried them outside rooms. The occurrence of S. aureus was 96% and 94% respectively for the towels and toothbrushes. Of the S. aureus isolated, 33.3% of sampled towels and 12.8% of the toothbrushes contained methicillin-resistant S. aureus.

CONCLUSION

This study found that, students are at risk of contracting infectious disease if their personal hygiene behaviours do not changed.

The SHIELD Orange County Project: Multidrug-resistant Organism Prevalence in 21 Nursing Homes and Long-term Acute Care Facilities in Southern California

BACKGROUND

Multidrug-resistant organisms (MDROs) spread between hospitals, nursing homes (NHs), and long-term acute care facilities (LTACs) via patient transfers. The Shared Healthcare Intervention to Eliminate Life-threatening Dissemination of MDROs in Orange County is a regional public health collaborative involving decolonization at 38 healthcare facilities selected based on their high degree of patient sharing. We report baseline MDRO prevalence in 21 NHs/LTACs.

METHODS

A random sample of 50 adults for 21 NHs/LTACs (18 NHs, 3 LTACs) were screened for methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus spp. (VRE), extended-spectrum β-lactamase-producing organisms (ESBL), and carbapenem-resistant Enterobacteriaceae (CRE) using nares, skin (axilla/groin), and peri-rectal swabs. Facility and resident characteristics associated with MDRO carriage were assessed using multivariable models clustering by person and facility.

RESULTS

Prevalence of MDROs was 65% in NHs and 80% in LTACs. The most common MDROs in NHs were MRSA (42%) and ESBL (34%); in LTACs they were VRE (55%) and ESBL (38%). CRE prevalence was higher in facilities that manage ventilated LTAC patients and NH residents (8% vs <1%, P < .001). MDRO status was known for 18% of NH residents and 49% of LTAC patients. MDRO-colonized adults commonly harbored additional MDROs (54% MDRO+ NH residents and 62% MDRO+ LTACs patients). History of MRSA (odds ratio [OR] = 1.7; confidence interval [CI]: 1.2, 2.4; P = .004), VRE (OR = 2.1; CI: 1.2, 3.8; P = .01), ESBL (OR = 1.6; CI: 1.1, 2.3; P = .03), and diabetes (OR = 1.3; CI: 1.0, 1.7; P = .03) were associated with any MDRO carriage.

CONCLUSIONS

The majority of NH residents and LTAC patients harbor MDROs. MDRO status is frequently unknown to the facility. The high MDRO prevalence highlights the need for prevention efforts in NHs/LTACs as part of regional efforts to control MDRO spread.

High Prevalence of Multidrug-Resistant Organism Colonization in 28 Nursing Homes: An "Iceberg Effect"

OBJECTIVE

Determine the prevalence of methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus spp. (VRE), extended-spectrum beta-lactamase producing organisms (ESBLs), and carbapenem-resistant Enterobacteriaceae (CRE) among residents and in the environment of nursing homes (NHs).

DESIGN

Point prevalence sampling of residents and environmental sampling of high-touch objects in resident rooms and common areas.

SETTING

Twenty-eight NHs in Southern California from 2016 to 2017.

PARTICIPANTS

NH participants in Project PROTECT, a cluster-randomized trial of enhanced bathing and decolonization vs routine care.

METHODS

Fifty residents were randomly sampled per NH. Twenty objects were sampled, including 5 common room objects plus 5 objects in each of 3 rooms (ambulatory, total care, and dementia care residents).

RESULTS

A total of 2797 swabs were obtained from 1400 residents in 28 NHs. Median prevalence of multidrug-resistant organism (MDRO) carriage per NH was 50% (range: 24%-70%). Median prevalence of specific MDROs were as follows: MRSA, 36% (range: 20%-54%); ESBL, 16% (range: 2%-34%); VRE, 5% (range: 0%-30%); and CRE, 0% (range: 0%-8%). A median of 45% of residents (range: 24%-67%) harbored an MDRO without a known MDRO history. Environmental MDRO contamination was found in 74% of resident rooms and 93% of common areas.

CONCLUSIONS AND IMPLICATIONS

In more than half of the NHs, more than 50% of residents were colonized with MDROs of clinical and public health significance, most commonly MRSA and ESBL. Additionally, the vast majority of resident rooms and common areas were MDRO contaminated. The unknown submerged portion of the iceberg of MDRO carriers in NHs may warrant changes to infection prevention and control practices, particularly high-fidelity adoption of universal strategies such as hand hygiene, environmental cleaning, and decolonization.

Antimicrobial Activity of Clinically Isolated Bacterial Species Against Staphylococcus aureus

Bacteria often exist in polymicrobial communities where they compete for limited resources. Intrinsic to this competition is the ability of some species to inhibit or kill their competitors. This phenomenon is pervasive throughout the human body where commensal bacteria block the colonization of incoming microorganisms. In this regard, molecular epidemiological and microbiota-based studies suggest that species-specific interactions play a critical role in the prevention of nasal colonization of the opportunistic pathogen Staphylococcus aureus. Despite this, S. aureus exists as part of the microbiota of ∼25% of the population, suggesting that the interplay between S. aureus and commensals can be complex. Microbiota studies indicate that several bacterial genera are negatively correlated with S. aureus colonization. While these studies paint a broad overview of bacterial presence, they often fail to identify individual species-specific interactions; a greater insight in this area could aid the development of novel antimicrobials. As a proof of concept study designed to identify individual bacterial species that possess anti-S. aureus activity, we screened a small collection of clinical isolates from the Walter Reed National Military Medical Center for the ability to inhibit multiple S. aureus strains. We found that the majority of the isolates (82%) inhibited at least one S. aureus strain; 23% inhibited all S. aureus strains tested. In total, seven isolates mediated inhibitory activity that was independent of physical contact with S. aureus, and seven isolates mediated bactericidal activity. 16S rRNA based-sequencing revealed that the inhibitory isolates belonged to the Acinetobacter, Agromyces, Corynebacterium, Microbacteria, Mycobacterium, and Staphylococcus genera. Unexpectedly, these included seven distinct Acinetobacter baumannii isolates, all of which showed heterogeneous degrees of anti-S. aureus activity. Defined mechanistic studies on specific isolates revealed that the inhibitory activity was retained in conditioned cell free medium (CCFM) derived from the isolates. Furthermore, CCFM obtained from S. saprophyticus significantly decreased mortality of S. aureus-infected Galleria mellonella caterpillars. While future studies will seek to define the molecular mechanisms of the inhibitory activities, our current findings support the study of polymicrobial interactions as a strategy to understand bacterial competition and to identify novel therapeutics against S. aureus and other pathogens.

Colonisation with pathogenic drug-resistant bacteria and Clostridioides difficile among residents of residential care facilities in Cape Town, South Africa: a cross-sectional prevalence study

Background

Residential care facilities (RCFs) act as reservoirs for multidrug-resistant organisms (MDRO). There are scarce data on colonisation with MDROs in Africa. We aimed to determine the prevalence of MDROs and C. difficile and risk factors for carriage amongst residents of RCFs in Cape Town, South Africa.

Methods

We performed a cross-sectional surveillance study at three RCFs. Chromogenic agar was used to screen skin swabs for methicillin-resistant S. aureus (MRSA) and stool samples for extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-E). Antigen testing and PCR was used to detect Clostridiodes difficile. Risk factors for colonisation were determined with logistic regression.

Results

One hundred fifty-four residents were enrolled, providing 119 stool samples and 152 sets of skin swabs. Twenty-seven (22.7%) stool samples were positive for ESBL-E, and 13 (8.6%) residents had at least one skin swab positive for MRSA. Two (1.6%) stool samples tested positive for C. difficile. Poor functional status (OR 1.3 (95% CI, 1.0-1.6)) and incontinence (OR 2.9 (95% CI, 1.2-6.9)) were significant predictors for ESBL-E colonisation. MRSA colonization appeared higher in frail care areas (8/58 v 5/94, p = 0.07).

Conclusions

There was a relatively high prevalence of colonisation with MDROs, particularly ESBL-E, but low C. difficile carriage, with implications for antibiotic prescribing and infection control practice.

Metabolic modelling of chronic wound microbiota predicts mutualistic interactions that drive community composition

AIMS

To identify putative mutualistic interactions driving community composition in polymicrobial chronic wound infections using metabolic modelling.

METHODS AND RESULTS

We developed a 12 species metabolic model that covered 74% of 16S rDNA pyrosequencing reads of dominant genera from 2963 chronic wound patients. The community model was used to predict species abundances averaged across this large patient population. We found that substantially improved predictions were obtained when the model was constrained with genera prevalence data and predicted abundances were averaged over 5000 ensemble simulations with community participants randomly determined according to the experimentally determined prevalences. Staphylococcus and Pseudomonas were predicted to exhibit a strong mutualistic relationship that resulted in community growth rate and diversity simultaneously increasing, suggesting that these two common chronic wound pathogens establish dominance by cooperating with less harmful commensal species. In communities lacking one or both dominant pathogens, other mutualistic relationship including Staphylococcus/Acinetobacter, Pseudomonas/Serratia and Streptococcus/Enterococcus were predicted consistent with published experimental data.

CONCLUSIONS

Mutualistic interactions were predicted to be driven by crossfeeding of organic acids, alcohols and amino acids that could potentially be disrupted to slow chronic wound disease progression.

SIGNIFICANCE AND IMPACT OF THE STUDY

Approximately 2% of the US population suffers from nonhealing chronic wounds infected by a combination of commensal and pathogenic bacteria. These polymicrobial infections are often resilient to antibiotic treatment due to the nutrient-rich wound environment and species interactions that promote community stability and robustness. The simulation results from this study were used to identify putative mutualistic interactions between bacteria that could be targeted to enhance treatment efficacy.

Bacterial Colonization in COPD Patients Admitted to a Rehabilitation Respiratory Unit and Impact on Length of Stay: A Real-Life Study

Bacterial colonization is a well-known phenomenon in acute care, but scant information is available regarding the rehabilitation setting. We retrospectively analyzed, in COPD patients admitted to a Respiratory Rehabilitative unit in 2010, the number of cultures requested, of positive cultures, and of cultures showing multiple drug resistant (MDR) organisms. We also compared hospital admissions (HA) with versus without positive cultures and with versus without MDR and investigated which baseline variables may predict length of stay (LOS) > 30 days. Of 286 COPD admissions (involving 269 patients, age 71 ± 11 years, males 66%), culture samples were requested in 62 (22%). The rate of colonization and of MDR organisms was 61 and 39%, respectively. Patients with a positive culture had a worse clinical condition and disability, and were more frequently tracheostomized, on invasive mechanical ventilation (MV) and admitted from/discharged to acute care. Patients with MDR cultures showed a lower exercise tolerance. Factors predicting LOS > 30 days were the presence of comorbidities, invasive MV, age > 65 years, and lower functional status, but not a positive culture or MDR presence. To our knowledge, this is the first real-life Italian study investigating the epidemiology of colonization and the association between colonization and LOS in a respiratory rehabilitation setting. Further investigation is necessary to clarify the relationship between colonization burden and patients' baseline clinical status and outcomes.

Environmental disinfection with photocatalyst as an adjunctive measure to control transmission of methicillin-resistant Staphylococcus aureus: a prospective cohort study in a high-incidence setting

Background

Environmental disinfection with continuously antimicrobial surfaces could offer superior control of surface bioburden. We sought to decide the efficacy of photocatalyst antimicrobial coating in reducing methicillin-resistant Staphylococcus aureus (MRSA) acquisition in high incidence setting.

Methods

We performed prospective cohort study involving patients hospitalized in medical intensive care unit. A titanium dioxide-based photocatalyst was coated on high touch surfaces and walls. Five months of pre-intervention data were compared with five months of post-intervention data. The incidence rates of multidrug-resistant organism acquisition and the rates of hospital-acquired blood stream infection, pneumonia, urinary tract infection, and Clostridium difficile–associated diseases were compared using Cox proportional hazards regression analysis.

Results

In total, 621 patients were included. There was significant decrease in MRSA acquisition rate after photocatalyst coating (hazard ratio, 0.37; 95% confidence interval, 0.14–0.99; p = 0.04). However, clinical identification of vancomycin-resistant Enterococcus spp. and multidrug-resistant Acinetobacter baumannii did not decrease significantly. The hazard of contracting hospital-acquired pneumonia during the intervention period compared to baseline period was 0.46 (95% confidence interval, 0.23–0.94; p = 0.03).

Conclusions

In conclusion, MRSA rate was significantly reduced after photocatalyst coating. We provide evidence that photocatalyst disinfection can be an adjunctive measure to control MRSA acquisition in high-incidence settings.

Trial registration

ISRCTN Registry (ISRCTN31972004). Registered retrospectively on November 19, 2018.

Electronic supplementary material

The online version of this article (10.1186/s12879-018-3555-1) contains supplementary material, which is available to authorized users.

The Role of Negative Methicillin-Resistant Staphylococcus aureus Nasal Surveillance Swabs in Predicting the Need for Empiric Vancomycin Therapy in Intensive Care Unit Patients

OBJECTIVES The role of methicillin-resistant Staphylococcus aureus (MRSA) nasal surveillance swabs (nasal swabs) in guiding decisions about prescribing vancomycin is unclear. We aimed to determine the likelihood that patients with negative MRSA nasal swabs develop subsequent MRSA infections; to assess avoidable vancomycin days for patients with negative nasal swabs; and to identify risk factors for having a negative nasal swab and developing a MRSA infection during the intensive care unit (ICU) stay. METHODS This retrospective cohort study was conducted in 6 ICUs at a tertiary-care hospital from December 2013 through June 2015. The negative predictive value (NPV), defined as the ability of a negative nasal swab to predict no subsequent MRSA infection, was calculated. Days of vancomycin continued or restarted after 3 days from the collection time of the first negative nasal swab were determined. A matched case-control study identified risk factors for having a negative nasal swab and developing MRSA infection. RESULTS Of 11,441 patients with MRSA-negative nasal swabs, the rate of subsequent MRSA infection was 0.22%. A negative nasal swab had a NPV of 99.4% (95% confidence interval [CI], 99.1%-99.6%). Vancomycin was continued or started after nasal swab results were available in 1,431 patients, translating to 7,364 vancomycin days. No risk factors associated with MRSA infection were identified. CONCLUSIONS In our hospital with a low prevalence of MRSA transmission, a negative MRSA nasal swab was helpful in identifying patients with low risk of MRSA infection in whom empiric vancomycin therapy could be stopped and in whom the subsequent initiation of vancomycin therapy during an ICU admission could be avoided. Infect Control Hosp Epidemiol 2018;39:290-296.

Nosocomial Outbreak of Extensively Drug-Resistant Acinetobacter baumannii Isolates Containing blaOXA-237 Carried on a Plasmid

Carbapenem antibiotics are among the mainstays for treating infections caused by Acinetobacter baumannii, especially in the Northwest United States, where carbapenem-resistant A. baumannii remains relatively rare. However, between June 2012 and October 2014, an outbreak of carbapenem-resistant A. baumannii occurred in 16 patients from five health care facilities in the state of Oregon. All isolates were defined as extensively drug resistant. Multilocus sequence typing revealed that the isolates belonged to sequence type 2 (international clone 2 [IC2]) and were >95% similar as determined by repetitive-sequence-based PCR analysis. Multiplex PCR revealed the presence of a bla_OXA carbapenemase gene, later identified as bla_OXA-237 Whole-genome sequencing of all isolates revealed a well-supported separate branch within a global A. baumannii phylogeny. Pacific Biosciences (PacBio) SMRT sequencing was also performed on one isolate to gain insight into the genetic location of the carbapenem resistance gene. We discovered that bla_OXA-237, flanked on either side by ISAba1 elements in opposite orientations, was carried on a 15,198-bp plasmid designated pORAB01-3 and was present in all 16 isolates. The plasmid also contained genes encoding a TonB-dependent receptor, septicolysin, a type IV secretory pathway (VirD4 component, TraG/TraD family) ATPase, an integrase, a RepB family plasmid DNA replication initiator protein, an alpha/beta hydrolase, and a BrnT/BrnA type II toxin-antitoxin system. This is the first reported outbreak in the northwestern United States associated with this carbapenemase. Particularly worrisome is that bla_OXA-237 was carried on a plasmid and found in the most prominent worldwide clonal group IC2, potentially giving pORAB01-3 great capacity for future widespread dissemination.

Osmotic Compounds Enhance Antibiotic Efficacy against Acinetobacter baumannii Biofilm Communities

Biofilm-associated infections are a clinical challenge, in part because a hydrated matrix protects the bacterial community from antibiotics. Herein, we evaluated how different osmotic compounds (maltodextrin, sucrose, and polyethylene glycol [PEG]) enhance antibiotic efficacy against Acinetobacter baumannii biofilm communities. Established (24-h) test tube biofilms (strain ATCC 17978) were treated with osmotic compounds in the presence or absence of 10× the MIC of different antibiotics (50 μg/ml tobramycin, 20 μg/ml ciprofloxacin, 300 μg/ml chloramphenicol, 30 μg/ml nalidixic acid, or 100 μg/ml erythromycin). Combining antibiotics with hypertonic concentrations of the osmotic compounds for 24 h reduced the number of biofilm bacteria by 5 to 7 log (P < 0.05). Increasing concentrations of osmotic compounds improved the effect, but there was a trade-off with increasing solution viscosity, whereby low-molecular-mass compounds (sucrose, 400-Da PEG) worked better than higher-mass compounds (maltodextrin, 3,350-Da PEG). Ten other A. baumannii strains were similarly treated with 400-Da PEG and tobramycin, resulting in a mean 2.7-log reduction in recoverable bacteria compared with tobramycin treatment alone. Multivariate regression models with data from different osmotic compounds and nine antibiotics demonstrated that the benefit from combining hypertonic treatments with antibiotics is a function of antibiotic mass and lipophilicity (r² > 0.82; P < 0.002), and the relationship was generalizable for biofilms formed by A. baumannii and Escherichia coli K-12. Augmenting topical antibiotic therapies with a low-mass hypertonic treatment may enhance the efficacy of antibiotics against wound biofilms, particularly when using low-mass hydrophilic antibiotics.IMPORTANCE Biofilms form a barrier that protects bacteria from environmental insults, including exposure to antibiotics. We demonstrated that multiple osmotic compounds can enhance antibiotic efficacy against Acinetobacter baumannii biofilm communities, but viscosity is a limiting factor, and the most effective compounds have lower molecular mass. The synergism between osmotic compounds and antibiotics is also dependent on the hydrophobicity and mass of the antibiotics. The statistical models presented herein provide a basis for predicting the optimal combination of osmotic compounds and antibiotics against surface biofilms communities.

Failure to Communicate: Transmission of Extensively Drug-Resistant bla OXA-237-Containing Acinetobacter baumannii-Multiple Facilities in Oregon, 2012-2014

OBJECTIVE To determine the scope, source, and mode of transmission of a multifacility outbreak of extensively drug-resistant (XDR) Acinetobacter baumannii. DESIGN Outbreak investigation. SETTING AND PARTICIPANTS Residents and patients in skilled nursing facilities, long-term acute-care hospital, and acute-care hospitals. METHODS A case was defined as the incident isolate from clinical or surveillance cultures of XDR Acinetobacter baumannii resistant to imipenem or meropenem and nonsusceptible to all but 1 or 2 antibiotic classes in a patient in an Oregon healthcare facility during January 2012-December 2014. We queried clinical laboratories, reviewed medical records, oversaw patient and environmental surveillance surveys at 2 facilities, and recommended interventions. Pulsed-field gel electrophoresis (PFGE) and molecular analysis were performed. RESULTS We identified 21 cases, highly related by PFGE or healthcare facility exposure. Overall, 17 patients (81%) were admitted to either long-term acute-care hospital A (n=8), or skilled nursing facility A (n=8), or both (n=1) prior to XDR A. baumannii isolation. Interfacility communication of patient or resident XDR status was not performed during transfer between facilities. The rare plasmid-encoded carbapenemase gene bla OXA-237 was present in 16 outbreak isolates. Contact precautions, chlorhexidine baths, enhanced environmental cleaning, and interfacility communication were implemented for cases to halt transmission. CONCLUSIONS Interfacility transmission of XDR A. baumannii carrying the rare blaOXA-237 was facilitated by transfer of affected patients without communication to receiving facilities. Infect Control Hosp Epidemiol 2017;38:1335-1341.

Epidemiology and clinical relevance of Staphylococcus aureus intestinal carriage: a systematic review and meta-analysis

INTRODUCTION

Recent data highlight the importance of screening more than one site for improving the detection of S. aureus colonization. Intestinal carriage is frequently under-investigated and its clinical impact ought to be defined a better way. Areas covered: This review and meta-analysis provide an updated overview of prevalence, characteristics and clinical significance of S. aureus intestinal carriage in different populations, both for methicillin-susceptible and -resistant S. aureus strains. Expert commentary: Intestinal S. aureus carriage is documented with higher prevalence in children and in patients with S. aureus skin and soft tissue infections. This site of colonization was shown to be associated with a high risk of dissemination in the environment and with S. aureus infection. Intestinal carriage is frequently retrieved in nasal carriers, reflecting probably an association with a high bacterial load. Exclusive intestinal carriage present in one third of intestinal carriers can be associated with infection. Comparative genotyping analysis of different strains from nasal and extra-nasal sites of carriage, including the intestinal ones, in the same individuals, would allow a better comprehension of the pathophysiology of S. aureus endogenous infection. It could also permit to improve the prevention of these infections by decolonization of sites implicated in infection genesis.

Persistent nasal carriers of Acinetobacter baumannii in long-term-care facilities

BACKGROUND

Acinetobacter baumannii and Staphylococcus aureus have persisted as 2 major pathogens worldwide.

AIM

We designed a prevalence study to investigate the prevalence of nasal carriage of S aureus and A baumannii in long-term-care facilities (LCTFs) and their collaborative community hospitals. In addition, we aimed to clarify persistent or nonpersistent carriage of the 2 organisms among residents of LTCFs.

METHODS

We performed a prevalence study concerning nasal carriers of A baumannii and S aureus in 3 LTCFs and 1 collaborative community hospital.

RESULTS

Seventy subjects were enrolled and clustered into 3 groups: the elderly sick group (n = 24), the elderly healthy group (n = 33), and the healthy health care worker group (n = 13). Nasal samples were collected, and the nuc and mecA genes of S aureus and the bla_OXA gene of A baumannii were analyzed by polymerase chain reaction. Among the 3 groups, the rate of nasal carriage of S aureus was approximately 0%-15%. However, the rate for A baumannii was approximately 54%-92%. Notably, the persistent carrier rate of A baumannii in the elderly sick group was 83.3% (20 out of 24) despite a 12.5% (3 out of 24) rate of carbapenem-resistant A baumannii.

CONCLUSIONS

We emphasized that the persistent nasal carriage of A baumannii in LTCFs could be another portal of exit to cause A baumannii infection in Taiwan.

Colonization of long term care facility patients with MDR-Gram-negatives during an Acinetobacter baumannii outbreak

BACKGROUND

We aimed to determine the prevalence of colonization by multidrug-resistant Gram-negative bacteria including ESBL-producing enterobacteriaceae, carbapenem-resistant enterobacteriaceae, Pseudomonas aeruginosa and Acinetobacter baumannii at two wards caring long term for patients with disorder of consciousness at the Geriatric Health Centers Graz, Austria. During our study we detected two A. baumannii outbreaks.

METHODS

In August 2015, we conducted a point-prevalence study. Inguinal and perianal swabs were taken from 38 patients and screened for multidrug-resistant Gram-negative rods using standard procedures. Six months after the initial investigation all patients were sampled again and use of antibiotics during the past 6 months and mortality was registered. Genetic relatedness of bacteria was evaluated by DiversiLab system.

RESULTS

Fifty percent of patients were colonized by multidrug-resistant Gram-negative isolates. Five patients harboured ESBL-producing enterobacteriaceae. No carbapenem-resistant enterobacteriaceae were detected. 13/38 patients were colonized by A. baumannii isolates (resistant to ciprofloxacin but susceptible to carbapenems). There was a significant difference in the prevalence of colonization by A. baumannii between ward 2 and ward 1 (60% vs. 5.6%, p < 0.001). Two clusters of A. baumannii isolates were identified including one isolate detected on a chair in a patient's room.

CONCLUSIONS

We detected a high prevalence of two multidrug-resistant A. baumannii strains in patients with disorder of consciousness at a LTCF in Graz, Austria. Our findings strongly suggest nosocomial cross-transmission between patients. An active surveillance strategy is warranted to avoid missing newly emerging pathogens.

Impact of chlorhexidine bathing on methicillin-resistant Staphylococcus aureus incidence in an endemic chronic care setting: A randomized controlled trial

We postulated that bathing with 2% chlorhexidine-impregnated antiseptic washcloths could reduce methicillin-resistant Staphylococcus aureus (MRSA) incidence among chronic care patients compared with nonantiseptic bathing. A total of 122 patients on 3 hospital units were enrolled in a 12-month, cluster-randomized, open-label, controlled trial, with 8 patients becoming MRSA positive. The 2% chlorhexidine-impregnated antiseptic washcloths reduced incidence by 71% (0.1 vs 0.44 cases per 1,000 patient days) (P = .14; Fisher exact). The detected difference was not statistically significant because of a low number of observed events.

Maltodextrin enhances biofilm elimination by electrochemical scaffold

Electrochemical scaffolds (e-scaffolds) continuously generate low concentrations of H2O2 suitable for damaging wound biofilms without damaging host tissue. Nevertheless, retarded diffusion combined with H2O2 degradation can limit the efficacy of this potentially important clinical tool. H2O2 diffusion into biofilms and bacterial cells can be increased by damaging the biofilm structure or by activating membrane transportation channels by exposure to hyperosmotic agents. We hypothesized that e-scaffolds would be more effective against Acinetobacter baumannii and Staphylococcus aureus biofilms in the presence of a hyperosmotic agent. E-scaffolds polarized at -600 mVAg/AgCl were overlaid onto preformed biofilms in media containing various maltodextrin concentrations. E-scaffold alone decreased A. baumannii and S. aureus biofilm cell densities by (3.92 ± 0.15) log and (2.31 ± 0.12) log, respectively. Compared to untreated biofilms, the efficacy of the e-scaffold increased to a maximum (8.27 ± 0.05) log reduction in A. baumannii and (4.71 ± 0.12) log reduction in S. aureus biofilm cell densities upon 10 mM and 30 mM maltodextrin addition, respectively. Overall ~55% decrease in relative biofilm surface coverage was achieved for both species. We conclude that combined treatment with electrochemically generated H2O2 from an e-scaffold and maltodextrin is more effective in decreasing viable biofilm cell density.

Multidrug-Resistant Gram-Negative Bacilli: Infection Control Implications

Antimicrobial resistance is a common iatrogenic complication of both modern life and medical care. Certain multidrug resistant and extensively drug resistant Gram-negative organisms pose the biggest challenges to health care today, predominantly owing to a lack of therapeutic options. Containing the spread of these organisms is challenging, and in reality, the application of multiple control measures during an evolving outbreak makes it difficult to measure the relative impact of each measure. This article reviews the usefulness of various infection control measures in containing the spread of multidrug-resistant Gram-negative bacilli.

Colistin enhances therapeutic efficacy of daptomycin or teicoplanin in a murine model of multiresistant Acinetobacter baumannii sepsis

We investigated the efficacy of colistin combined with teicoplanin or daptomycin in an experimental mouse model of multiresistant Acinetobacter baumannii infection. Animal received intraperitoneally 1ml saline containing 2×10¹⁰CFU of A. baumannii. Colistin, daptomycin, teicoplanin, and colistin plus daptomycin or teicoplanin were given by intraperitoneal administration 2h after bacterial challenge. A control group received sodium chloride solution. In the in vitro study A. baumannii showed to be susceptible only to colistin with MIC of 2mg/l. In the in vivo study, colistin alone showed a good antimicrobial efficacy. When combined with teicoplanin or daptomycin, colistin produced the lowest bacterial and the best survival rates. In immunological studies, when colistin was associated to daptomycin or teicoplanin, both the number and the cytotoxic activity of NK cells increased. In conclusion, colistin combined with teicoplanin or daptomycin may improve the therapy of multiresistant A. baumannii infection.

Effectiveness of hand hygiene depends on the patient's health condition and care environment

AIM

The present authors examined how patient hand contamination was associated with underlying disease and treatment environment in order to determine effective hand hygiene methods.

METHODS

Samples were collected from inpatients (45 with hematological malignancies, 48 postoperative), outpatients (48 undergoing hemodialysis, 55 on chemotherapy), and 44 individuals living in nursing homes. All participants provided informed consent for study participation. All subjects performed hand hygiene. Before and after hand hygiene, samples of bacteria were collected from the palm of the hand onto agar media. Bacteria were counted and bacterial strains were identified. The authors then collected smear samples from the contralateral palm and measured adenosine triphosphate (ATP) levels.

RESULTS

Patient hand contamination was the highest in hemodialysis patients, followed by residents of nursing homes, postoperative patients, patients with cancer receiving chemotherapy, and patients of hematological malignancies. Regardless of the underlying disease and treatment environment, patients were able to reduce the number of bacterial colonies and ATP by proper hand hygiene. Compared with wet wipes, hand washing seemed to remove bacteria more effectively. Methicillin-resistant Staphylococcus aureus (MRSA) was detected in 30 subjects, none of whom were patients of hematological malignancies. Of these, 19 tested negative for MRSA after performing proper hand hygiene.

CONCLUSION

Patient hand contamination is affected by underlying disease and care environment, but can be reduced by encouraging proper hand washing. Proper patient hand hygiene can reduce MRSA on patients' hands, and thus may serve as an effective tool for prevention of healthcare-associated infections.

Prevalence of and risk factors for multidrug-resistant Acinetobacter baumannii colonization among high-risk nursing home residents

OBJECTIVE

To characterize the epidemiology of multidrug-resistant (MDR) Acinetobacter baumannii colonization in high-risk nursing home (NH) residents.

DESIGN

Nested case-control study within a multicenter prospective intervention trial.

SETTING

Four NHs in Southeast Michigan. PARTICIPANTS Case patients and control subjects were NH residents with an indwelling device (urinary catheter and/or feeding tube) selected from the control arm of the Targeted Infection Prevention study. Cases were residents colonized with MDR (resistant to ≥3 classes of antibiotics) A. baumannii; controls were never colonized with MDR A. baumannii.

METHODS

For active surveillance cultures, specimens from the nares, oropharynx, groin, perianal area, wounds, and device insertion site(s) were collected upon study enrollment, day 14, and monthly thereafter. A. baumannii strains and their susceptibilities were identified using standard microbiologic methods.

RESULTS

Of 168 NH residents, 25 (15%) were colonized with MDR A. baumannii. Compared with the 143 controls, cases were more functionally disabled (Physical Self-Maintenance Score >24; odds ratio, 5.1 [95% CI, 1.8-14.9]; P<.004), colonized with Proteus mirabilis (5.8 [1.9-17.9]; P<.003), and diabetic (3.4 [1.2-9.9]; P<.03). Most cases (22 [88%]) were colonized with multiple antibiotic-resistant organisms and 16 (64%) exhibited co-colonization with at least one other resistant gram-negative bacteria.

CONCLUSION

Functional disability, P. mirabilis colonization, and diabetes mellitus are important risk factors for colonization with MDR A. baumannii in high-risk NH residents. A. baumannii exhibits widespread antibiotic resistance and a preference to colonize with other antibiotic-resistant organisms, meriting enhanced attention and improved infection control practices in these residents.

Clinical test to detect mecA and antibiotic resistance in Staphylococcus aureus, based on novel biotechnological methods

BACKGROUND AND OBJECTIVE

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most common organisms isolated from clinical samples, and has been associated with morbidity and mortality among hospitalized patients. The aim of this study was to evaluate the prevalence and antibiotic susceptibility patterns among MRSA and methicillin-sensitive S. aureus (MSSA) isolates collected from four hospitals in Iran.

MATERIAL AND METHODS

A total of 183 isolates of S. aureus were collected from various clinical specimens of four hospitals in Iran. The isolates were identified by using the conventional biochemical tests. Three methods-oxacillin agar disk diffusion, oxacillin agar screening, and PCR- were applied to determine susceptibility to oxacillin. The conventional disk agar diffusion test was used to evaluate the antibiotic sensitivity of our isolates against 15 antibiotics, according to the guidelines of the Clinical and Laboratory Standards Institute (CLSI).

RESULTS

Of 183 isolates, 77 isolates (42.1%) were found to be MRSA, by the PCR method. The highest antibiotic resistance was found to be against penicillin, co-trimoxazole, erythromycin, and tetracycline respectively. All isolates were susceptible to vancomycin, according to the results of disk agar diffusion. Among other antibiotics, teicoplanin (84%) and fusidic acid (80.5%) were more active against MRSA isolates. For the different methods evaluated, the sensitivities and specificities were as follows: for disk agar diffusion (84.9% and 95.9%) and for agar screening test with oxacillin concentrations of 0.6 μg/ml (70.8% and 97.4%), 4 μg/ml (96.1%and 97.2%) and 6 μg/ml (96% and 96.3%), respectively.

CONCLUSION

The results of our study showed that 47% of S. aureus isolates were MRSA. Overall, in this research study, resistance to all test antimicrobial agents in MRSA isolates were higher than that of MSSA isolates. Our results also revealed that 85% of mecA-positive isolates and 15% of mecA-negative isolates were resistant to methicillin; while 96% of mecA-negative isolates were sensitive to methicillin. Meanwhile 4% of mecA-positive isolates were also sensitive to methicillin.

Healthcare-associated pathogens and nursing home policies and practices: results from a national survey

OBJECTIVE To examine the prevalence of healthcare-associated pathogens and the infection control policies and practices in a national sample of nursing homes (NHs). METHODS In 2012, we conducted a national survey about the extent to which NHs follow suggested infection control practices with regard to 3 common healthcare-associated pathogens: methicillin-resistant Staphylococcus aureus, Clostridium difficile, and extended-spectrum β-lactamase producers, and their prevalence in NHs. We adapted a previously used and validated NH infection control survey, including questions on prevalence, admission and screening policies, contact precautions, decolonization, and cleaning practices. RESULTS A total of 1,002 surveys were returned. Of the responding NHs, 14.2% were less likely to accept residents with methicillin-resistant Staphylococcus aureus, with the principal reason being lack of single or cohort rooms. NHs do not routinely perform admission screening (96.4%) because it is not required by regulation (56.2%) and would not change care provision (30.7%). Isolation strategies vary substantially, with gloves being most commonly used. Most NHs (75.1%) do not decolonize carriers of methicillin-resistant Staphylococcus aureus, but some (10.6%) decolonize more than 90% of residents. Despite no guidance on how resident rooms on contact precautions should be cleaned, 59.3% of NHs report enhanced cleaning for such rooms. CONCLUSION Overall, NHs tend to follow voluntary infection control guidelines only if doing so does not require substantial financial investment in new or dedicated staff or infrastructure.

A national intervention to prevent the spread of carbapenem-resistant Enterobacteriaceae in Israeli post-acute care hospitals

OBJECTIVE

Patients hospitalized in post-acute care hospitals (PACHs) constitute an important reservoir of antimicrobial-resistant bacteria. High carriage prevalence of carbapenem-resistant Enterobacteriaceae (CRE) has been observed among patients hospitalized in PACHs. The objective of the study is to describe the impact of a national infection control intervention on the prevalence of CRE in PACHs.

DESIGN

A prospective cohort interventional study.

SETTING

Thirteen PACHs in Israel.

INTERVENTION

A multifaceted intervention was initiated between 2008 and 2011 as part of a national program involving all Israeli healthcare facilities. The intervention has included (1) periodic on-site assessments of infection control policies and resources, using a score comprised of 16 elements; (2) assessment of risk factors for CRE colonization; (3) development of national guidelines for CRE control in PACHs involving active surveillance and contact isolation of carriers; and (4) 3 cross-sectional surveys of rectal carriage of CRE that were conducted in representative wards.

RESULTS

The infection control score increased from 6.8 to 14.0 (P < .001) over the course of the study period. A total of 3,516 patients were screened in the 3 surveys. Prevalence of carriage among those not known to be carriers decreased from 12.1% to 7.9% (P = .008). Overall carrier prevalence decreased from 16.8% to 12.5% (P = .013). Availability of alcohol-based hand rub, appropriate use of gloves, and a policy of CRE surveillance at admission to the hospital were independently associated with lower new carrier prevalence.

CONCLUSION

A nationwide infection control intervention was associated with enhanced infection control measures and a reduction in the prevalence of CRE in PACHs.

Antimicrobial stewardship in long-term care facilities

Although antimicrobial stewardship has been shown to improve microbiologic susceptibility patterns, decrease drug toxicities, and lower overall drug costs in the inpatient setting, there are few studies assessing programs in the long-term care (LTC) setting. Implementing antimicrobial stewardship programs in LTC settings can be challenging as the LTC setting houses a unique population of frail and older adults with several preexisting conditions and multiple risk factors for colonization with multidrug-resistant organisms. Antimicrobial stewardship has an important role in decreasing inappropriate antibiotic use, encouraging targeted treatment of specific disease states, and limiting the untoward effects and costs of antimicrobials in this vulnerable population.

Four Years of Surveillance Cultures at a Long-Term Acute Care Hospital

Objective.

To characterize the degree of colonization with multidrug-resistant organisms (MDROs) among patients admitted to a long-term acute care hospital.

Design.

Ecologie Study.

Setting.

A 70-bed long-term acute care hospital (a hospital within a hospital) in the greater Chicago area.

Methods.

As part of an infection control initiative, specimens were collected from all consecutively admitted patients for culture of MDROs within 72 hours of admission. Cultures from July 28, 2005, through November 1, 2008, were analyzed on the basis of the bodily site from which the isolate was recovered and the organisms identified. If MDROs were yielded by culture of specimens that were obtained from 24 hours to 30 days after collection of the patient's original set of specimens, these MDROs were removed from the analysis. In addition, repeat rectal swab samples were collected for culture at 2 weeks after admission for all consecutive patients admitted from January 1 through March 31, 2007.

Results.

A total of 1,739 patients with a total of 5,198 specimens met entry criteria. Of the corresponding 5,198 surveillance cultures, 1,580 (30%) were positive for MDROs. Of the 1,739 patients, 947 (54%) had a culture-positive specimen recovered from any site. Vancomycin-resistant Enterococcus was the organism most commonly isolated in cultures of rectal swab samples (in 38% of such cultures) and wounds (in 18% of such cultures). The rate of rectal carriage of vancomycin-resistant Enterococcus increased from 29% in 2005 to 44% in 2008.

Predictors of Rectal Carriage of Carbapenem-Resistant Enterobacteriaceae (CRE) among Patients with Known CRE Carriage at Their Next Hospital Encounter

Background.

Carbapenem-resistant Enterobacteriaceae (CRE) are important extremely drug-resistant pathogens that have emerged during the past decade. Early identification and isolation of carriers are key components of an effective infection control strategy in healthcare facilities. Very little is known about the natural history of CRE carriage. We aimed to determine the predictors of a positive CRE rectal screen test among patients with known CRE carriage screened at their next hospital encounter.

Methods.

A case-control study was conducted. Sixty-six patients who tested positive for CRE carriage were surveyed for CRE rectal carriage at the next hospital encounter; screen-positive patients were compared with screen-negative control patients. Data were extracted from the patients' medical records and from the hospital computerized database.

Results.

Twenty-three case patients and 43 control patients were identified. Predictors for a positive CRE rectal carriage test were (1) prior fluoroquinolone use (odds ratio [OR], 4.27; 95% confidence interval [CI], 1.10–16.6), (2) admission from an institution or another hospital (OR, 4.04; 95% CI, 1.33–12.37), and (3) time interval less than or equal to 3 months since the first positive CRE test (OR, 3.59; 95% CI, 1.24–10.37). Among patients with no predictor variables, the likelihood of having a positive screen test at the next hospital encounter was 1/7. If they had at least 1 predictor, the likelihood increased to 1/2.

Conclusions.

Prior fluoroquinolone use, transfer from another healthcare facility, and admission less than or equal to 3 months since the first CRE isolation are predictors of persistent CRE rectal carriage. These predictors can be used in designing CRE prevention strategies.

Assessing the Burden of Acinetobacter baumannii in Maryland: A Statewide Cross-Sectional Period Prevalence Survey

Objective.

To determine the prevalence ofAcinetobacter baumannii, an important healthcare-associated pathogen, among mechanically ventilated patients in Maryland.

Design.

The Maryland MDRO Prevention Collaborative performed a statewide cross-sectional active surveillance survey of mechanically ventilated patients residing in acute care and long-term care (LTC) facilities. Surveillance cultures (sputum and perianal) were obtained from all mechanically ventilated inpatients at participating facilities during a 2-week period.

Setting.

All healthcare facilities in Maryland that provide care for mechanically ventilated patients were invited to participate.

Patients.

Mechanically ventilated patients, known to be at high risk for colonization and infection withA. baumannii, were included.

Results.

Seventy percent (40/57) of all eligible healthcare facilities participated in the survey, representing both acute care (n= 30) and LTC (n= 10) facilities in all geographic regions of Maryland. Surveillance cultures were obtained from 92% (358/390) of eligible Patients.A. baumanniiwas identified in 34% of all mechanically ventilated patients in Maryland; multidrug-resistantA. baumanniiwas found in 27% of all Patients.A. baumanniiwas detected in at least 1 patient in 49% of participating facilities; 100% of LTC facilities had at least 1 patient with A.baumannii, compared with 31% of acute care facilities.A. baumanniiwas identified from all facilities in which 10 or more patients were sampled.

Conclusions.

A.baumanniiis common among mechanically ventilated patients in both acute care and LTC facilities throughout Maryland, with a high proportion of isolates demonstrating multidrug resistance.

Multidrug-resistant Acinetobacter baumannii infection, colonization, and transmission related to a long-term care facility providing subacute care

OBJECTIVE

To investigate Acinetobacter baumannii infection, colonization, and transmission related to a long-term care facility (LTCF) providing subacute care (facility A).

METHODS

We reviewed facility A and affiliated local hospital records for facility A residents with A. baumannii isolated during the period January 2009 through February 2010 and compared A. baumannii antimicrobial resistance patterns of residents with those of hospital patients. During March 2010, we implemented a colonization survey of facility A residents who received respiratory support or who could provide sputum samples and looked for A. baumannii colonization risks. Available clinical and survey isolates underwent pulsed-field gel electrophoresis (PFGE); PFGE strains were linked with overlapping stays to identify possible transmission.

RESULTS

During the period January 2009 through February 2010, 33 facility A residents had A. baumannii isolates; all strains were multidrug resistant (MDR), which was a significantly higher prevalence of MDR strains than that found among isolates from hospital patients (81 [66%] of 122 hospital patient isolates were MDR; P < .001). The sputum survey found that 14 (20%) of 70 residents had A. baumannii colonization, which was associated with ventilator use (adjusted odds ratio, 4.24 [95% confidence interval, 1.06-16.93]); 12 (86%) of 14 isolates were MDR. Four facility A resident groups clustered with 3 PFGE strains and overlapping stays. One of these facility A residents also clustered with 3 patients at an affiliated hospital.

CONCLUSIONS

We documented substantial MDR A. baumannii infections and colonization with probable intra- and interfacility spread associated with a single LTCF providing subacute care. Given the limited infection prevention and antimicrobial stewardship resources in such settings, regional collaborations among facilities across the spectrum of health care are needed to address this MDR threat.

Assessment of Antimicrobial Stewardship Activities in a Large Metropolitan Area

PURPOSE

To describe antimicrobial stewardship programs (ASPs) of acute and long-term acute care (LTAC) hospitals in Houston, Texas.

METHODS

Two-part survey to clinical pharmacists and pharmacy directors. All acute care and LTAC facilities from the Harris County Medical Society database were invited to participate.

RESULTS

In part 1 of the telephone survey, 82 facilities within Houston, Harris county, were contacted by telephone of which 51 responded (response rate: 62%). Of respondents, 55% (n = 28) reported having an active ASP and 8% (n = 4) planned implementation within 12 months. Acute care and LTAC hospitals reported ASPs in 57% and 67% of facilities, respectively. Physician champions were involved in 71% (n = 20) of active ASPs; clinical pharmacists were involved in 75% (n = 21) of programs. In part II, 22 (43%) facilities completed the online survey; postprescription review with feedback was used in facilities with an ASP and medical training program (5 of 5) while formulary restriction was in facilities without stewardship or medical training (6 of 8).

CONCLUSION

This is the first major survey of ASP in a major metropolitan area. The stewardship effort in the city of Houston is encouraging; we expect the number of stewardship programs in all facilities will continue to rise as focus on antimicrobial resistance grows.

Protective effect of methicillin-susceptible Staphylococcus aureus carriage against methicillin-resistant S. aureus acquisition in nursing homes: a prospective cross-sectional study

OBJECTIVE

To evaluate whether an ecologic inverse association exists between methicillin-susceptible Staphylococcus aureus (MSSA) prevalence and methicillin-resistant S. aureus (MRSA) prevalence in nursing homes.

METHODS

We conducted a secondary analysis of a prospective cross-sectional study of S. aureus prevalence in 26 nursing homes across Orange County, California, from 2008-2011. Admission prevalence was assessed using bilateral nares swabs collected from all new residents within 3 days of admission until 100 swabs were obtained. Point prevalence was assessed from a representative sample of 100 residents. Swab samples were plated on 5% sheep blood agar and Spectra MRSA chromogenic agar. If MRSA was detected, no further tests were performed. If MRSA was not detected, blood agar was evaluated for MSSA growth. We evaluated the association between MRSA and MSSA admission and point prevalence using correlation and linear regression testing.

RESULTS

We collected 3,806 total swabs. MRSA and MSSA admission prevalence were not correlated (r = -0.40, P = .09). However, MRSA and MSSA point prevalence were negatively correlated regardless of whether MSSA prevalence was measured among all residents sampled (r = -0.67, P = .0002) or among those who did not harbor MRSA (r = -0.41, P = .04). This effect persisted in regression models adjusted for the percentage of residents with diabetes (β = -0.73, P = .04), skin lesions (β = -1.17, P = .002), or invasive devices (β = -1.4, P = .0006).

CONCLUSIONS

The inverse association between MRSA and MSSA point prevalence and minimal association on admission prevalence suggest MSSA carriage may protect against MRSA acquisition in nursing homes. The minimal association on admission prevalence further suggests competition may occur during nursing home stays.

Prevalence of multidrug-resistant organisms and risk factors for carriage in long-term care facilities: a nested case-control study

BACKGROUND

Long-term care facilities (LTCFs) are a potentially important reservoir of multidrug-resistant (MDR) organisms; however, limited data exist.

METHODS

A point-prevalence study was conducted in four co-located LTCFs in Australia. Nasal and rectal swabs were cultured for methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE) and MDR Gram-negative bacilli (GNB). Molecular typing and resistance detection were performed. Risk factors for colonization with an MDR organism were determined using a nested case-control study.

RESULTS

Consent was obtained from 115 (85%) of 136 eligible participants. Forty-one (36%) residents carried at least one type of MDR organism. The prevalence was 16% MRSA (n = 18), 6% VRE (n = 7) and 21% MDR GNB [n = 24; including extended-spectrum β-lactamase (ESBL)-producing Escherichia coli (n = 12) and Acinetobacter baumannii (n = 6)]. The majority of ESBL-producing E. coli and A. baumannii were clonal. Current wound management [adjusted OR (AOR) 8.81 (95% CI 2.78-27.94), P < 0.001], medical device in situ [AOR 5.58 (95% CI 1.34-23.32), P = 0.018] and pressure ulcer [AOR 3.69 (95% CI 1.06-12.86), P = 0.04] were independent risk factors for MDR organism colonization. Advanced dementia [AOR 3.54 (95% CI 1.23-10.23), P = 0.02] and prolonged antibiotic use [AOR 2.95 (95% CI 1.01-8.60), P = 0.047] were independently associated with MRSA colonization, whilst current wound management [AOR 15.59 (95% CI 4.85-50.10), P < 0.001] and fluoroquinolone use [AOR 4.27 (95% CI 1.20-15.25), P = 0.025] were risk factors for MDR GNB colonization.

CONCLUSIONS

LTCFs are an important reservoir of MDR organisms, with person-to-person transmissions being a potential issue. We have identified several predictors of colonization with MDR organisms, allowing a more targeted management of high-risk residents.

The association between comorbid illness, colonization status, and acute hospitalization in patients receiving prolonged mechanical ventilation

BACKGROUND

Long-term acute care (LTAC) hospitals provide specialized care for survivors of critical illness who require prolonged mechanical ventilation. These chronically ill patients often have multiple comorbidities and are colonized with antibiotic-resistant organisms. We investigated the association of comorbidities and colonization status with outcomes in patients requiring prolonged mechanical ventilation in an LTAC facility. We hypothesized that comorbidity burden and colonization with multiple drug resistant organisms would be associated with worse clinical outcomes.

METHODS

We performed a retrospective, cohort study of 157 mechanically ventilated subjects in an urban LTAC facility admitted from January 2007 to September 2009. Comorbidity burden was documented from pre-admission data using the Charlson Comorbidity Index. Colonization data were obtained from surveillance cultures. Outcomes studied included transfer back to acute care facilities, stay, and ventilator weaning status.

RESULTS

Within 60 days, 58.6% of subjects were transferred back to an acute care facility. The most common reason for transfer was infection/sepsis (37%). The Charlson Comorbidity Index of subjects transferred to acute care, versus those who were not, was 4.9 ± 3.1 versus 3.6 ± 2.7 (P = .01), an odds ratio of 1.1 for each 1-point increase in Charlson Comorbidity Index (95% CI 1.03-1.71, P = .02). Colonization with acinetobacter was associated with higher incidence of transfer (71% vs 51%, P = .01). The odds ratio for transfer to acute care was 1.3 for each additional organism colonizing a subject (95% CI 1.11-1.53, P = .006).

CONCLUSIONS

Higher comorbidity burden and colonization status were associated with increased risk of transfer to acute care. Further investigation is needed to clarify this relationship between comorbidity burden and colonization with change in clinical status.

Epidemiology of bloodstream infections caused by Acinetobacter baumannii and impact of drug resistance to both carbapenems and ampicillin-sulbactam on clinical outcomes

Acinetobacter baumannii has become a leading cause of bloodstream infections (BSI) in health care settings. Although the incidence of infection with carbapenem- and ampicillin-sulbactam-resistant (CASR) A. baumannii has increased, there is a scarcity of studies which investigate BSI caused by CASR A. baumannii. A retrospective cohort study was conducted on adult patients with BSI caused by A. baumannii and who were admitted to the Detroit Medical Center between January 2006 and April 2009. Medical records were queried for patients' demographics, antimicrobial exposures, comorbidities, hospital stay, and clinical outcomes. Bivariate analyses and logistic regression were employed in the study. Two hundred seventy-four patients with BSI caused by A. baumannii were included in the study: 68 (25%) caused by CASR A. baumannii and 206 (75%) caused by non-CASR A. baumannii. In multivariate analysis, factors associated with BSI caused by CASR A. baumannii included admission with a rapidly fatal condition (odds ratio [OR] = 2.83, 95% confidence interval [CI] = 1.27 to 6.32, P value = 0.01) and prior use of antimicrobials (OR = 2.83, 95% CI = 1.18 to 6.78, P value = 0.02). In-hospital mortality rates for BSI caused by CASR A. baumannii were significantly higher than those for non-CASR A. baumannii-induced BSI (43% versus 20%; OR = 3.0, 95% CI = 1.60 to 5.23, P value < 0.001). However, after adjusting for potential confounders, the association between BSI caused by CASR A. baumannii and increased risk of in-hospital mortality was not significant (OR = 1.15, 95% CI = 0.51 to 2.63, P value = 0.74). This study demonstrated that CASR A. baumannii had a distinct epidemiology compared to more susceptible A. baumannii strains; however, clinical outcomes were similar for the two groups. Admission with a rapidly fatal condition was an independent predictor for both CASR A. baumannii and in-hospital mortality.

Comparison of the bacterial isolates and antibiotic resistance patterns of elderly nursing home and general community patients

BACKGROUND

Nursing home-acquired infections may differ from general community-acquired infections in bacteriology and antibiotic resistance. However, there are currently limited data on this topic in the Australian setting.

AIMS

To compare bacterial isolates and antibiotic resistance patterns, from pathology specimens of nursing home and community patients, and to comment on the suitability of empiric antibiotic guidelines for nursing home-acquired infection.

METHODS

This was a retrospective cohort study of patients, aged ≥ 65 years, who resided in either nursing homes or the general community. Patients with a hospital admission in the previous 28 days were excluded. Positive specimen cultures, collected between July 2003 and June 2008 in the Emergency Department and Outpatient Clinics of the Austin Hospital (Melbourne), were examined. The main outcome measures were the bacterial isolates, and their antibiotic resistance patterns, of patients from nursing homes and the general community.

RESULTS

Specimens of blood (638), sputum (425), urine (4044) and wound cultures (785) were examined. The bacteriology of blood culture isolates did not differ between the two groups (P= 0.3). However, the bacteriology of sputum, urine and wound cultures differed significantly between the groups (P= 0.025, P < 0.001, P= 0.004 respectively). There were also higher proportions of antibiotic resistance among some bacteria in nursing home patients, especially methicillin resistance among Staphylococcus aureus isolates across all specimen types, and resistance to several empiric antibiotics among Enterobacteriaceae isolates in urine cultures.

CONCLUSION

Empiric antibiotic guidelines appear adequate to treat nursing home-acquired septicaemia and pneumonia. However, guidelines for urinary tract infections and wound infections may need to be refined.

The importance of nursing homes in the spread of methicillin-resistant Staphylococcus aureus (MRSA) among hospitals

BACKGROUND

Hospital infection control strategies and programs may not consider control of methicillin-resistant Staphylococcus aureus (MRSA) in nursing homes in a county.

METHODS

Using our Regional Healthcare Ecosystem Analyst, we augmented our existing agent-based model of all hospitals in Orange County (OC), California, by adding all nursing homes and then simulated MRSA outbreaks in various health care facilities.

RESULTS

The addition of nursing homes substantially changed MRSA transmission dynamics throughout the county. The presence of nursing homes substantially potentiated the effects of hospital outbreaks on other hospitals, leading to an average 46.2% (range, 3.3%-156.1%) relative increase above and beyond the impact when only hospitals are included for an outbreak in OC's largest hospital. An outbreak in the largest hospital affected all other hospitals (average 2.1% relative prevalence increase) and the majority (~90%) of nursing homes (average 3.2% relative increase) after 6 months. An outbreak in the largest nursing home had effects on multiple OC hospitals, increasing MRSA prevalence in directly connected hospitals by an average 0.3% and in hospitals not directly connected through patient transfers by an average 0.1% after 6 months. A nursing home outbreak also had some effect on MRSA prevalence in other nursing homes.

CONCLUSIONS

Nursing homes, even those not connected by direct patient transfers, may be a vital component of a hospital's infection control strategy. To achieve effective control, a hospital may want to better understand how regional nursing homes and hospitals are connected through both direct and indirect (with intervening stays at home) patient sharing.

Effect of daily chlorhexidine bathing on hospital-acquired infection

BACKGROUND

Results of previous single-center, observational studies suggest that daily bathing of patients with chlorhexidine may prevent hospital-acquired bloodstream infections and the acquisition of multidrug-resistant organisms (MDROs).

METHODS

We conducted a multicenter, cluster-randomized, nonblinded crossover trial to evaluate the effect of daily bathing with chlorhexidine-impregnated washcloths on the acquisition of MDROs and the incidence of hospital-acquired bloodstream infections. Nine intensive care and bone marrow transplantation units in six hospitals were randomly assigned to bathe patients either with no-rinse 2% chlorhexidine-impregnated washcloths or with nonantimicrobial washcloths for a 6-month period, exchanged for the alternate product during the subsequent 6 months. The incidence rates of acquisition of MDROs and the rates of hospital-acquired bloodstream infections were compared between the two periods by means of Poisson regression analysis.

RESULTS

A total of 7727 patients were enrolled during the study. The overall rate of MDRO acquisition was 5.10 cases per 1000 patient-days with chlorhexidine bathing versus 6.60 cases per 1000 patient-days with nonantimicrobial washcloths (P=0.03), the equivalent of a 23% lower rate with chlorhexidine bathing. The overall rate of hospital-acquired bloodstream infections was 4.78 cases per 1000 patient-days with chlorhexidine bathing versus 6.60 cases per 1000 patient-days with nonantimicrobial washcloths (P=0.007), a 28% lower rate with chlorhexidine-impregnated washcloths. No serious skin reactions were noted during either study period.

CONCLUSIONS

Daily bathing with chlorhexidine-impregnated washcloths significantly reduced the risks of acquisition of MDROs and development of hospital-acquired bloodstream infections. (Funded by the Centers for Disease Control and Prevention and Sage Products; ClinicalTrials.gov number, NCT00502476.).

Hand hygiene opportunities in pediatric extended care facilities

INTRODUCTION

Introduction: Children in extended care facilities (ECFs) are at risk of healthcare-associated infections, but little hand hygiene (HH) research has been conducted in this unique setting.

METHODS

Eight children across four pediatric ECFs were observed for a cumulative 128 hours, and all care giver HH opportunities were characterized by the World Health Organization's '5 Moments for HH'. Data were analyzed using Pearson's χ2 test.

RESULTS

Observers documented 865 HH opportunities. Overall HH adherence was 43% and was significantly higher among clinical care givers than among non-clinical care givers (61% and 14%, respectively, (p < .01).

CONCLUSIONS

Hand hygiene adherence was low, suggesting multiple opportunities for transmission of infectious agents.