Graham M. Snyder

Frequent Multidrug-Resistant Acinetobacter baumannii Contamination of Gloves, Gowns, and Hands of Healthcare Workers

BACKGROUND Multidrug-resistant (MDR) gram-negative bacilli are important nosocomial pathogens. OBJECTIVE To determine the incidence of transmission of MDR Acinetobacter baumannii and Pseudomonas aeruginosa from patients to healthcare workers (HCWs) during routine patient care. DESIGN Prospective cohort study. SETTING Medical and surgical intensive care units. Methods. We observed HCWs who entered the rooms of patients colonized with MDR A. baumannii or colonized with both MDR A. baumannii and MDR P. aeruginosa. We examined their hands before room entry, their disposable gloves and/or gowns upon completion of patient care, and their hands after removal of gloves and/or gowns and before hand hygiene. RESULTS Sixty-five interactions occurred with patients colonized with MDR A. baumannii and 134 with patients colonized with both MDR A. baumannii and MDR P. aeruginosa. Of 199 interactions between HCWs and patients colonized with MDR A. baumannii, 77 (38.7% [95% confidence interval {CI}, 31.9%-45.5%]) resulted in HCW contamination of gloves and/or gowns, and 9 (4.5% [95% CI, 1.6%-7.4%]) resulted in contamination of HCW hands after glove removal before hand hygiene. Of 134 interactions with patients colonized with MDR P. aeruginosa, 11 (8.2% [95% CI, 3.6%-12.9%]) resulted in HCW contamination of gloves and/or gowns, and 1 resulted in HCW contamination of hands. Independent risk factors for contamination with MDR A. baumannii were manipulation of wound dressing (adjusted odds ratio [aOR], 25.9 [95% CI, 3.1-208.8]), manipulation of artificial airway (aOR, 2.1 [95% CI, 1.1-4.0]), time in room longer than 5 minutes (aOR, 4.3 [95% CI, 2.0-9.1]), being a physician or nurse practitioner (aOR, 7.4 [95% CI, 1.6-35.2]), and being a nurse (aOR, 2.3 [95% CI, 1.1-4.8]). CONCLUSIONS Gowns, gloves, and unwashed hands of HCWs were frequently contaminated with MDR A. baumannii. MDR A. baumannii appears to be more easily transmitted than MDR P. aeruginosa and perhaps more easily transmitted than previously studied methicillin-resistant Staphylococcus aureus or vancomycin-resistant Enterococcus. This ease of transmission may help explain the emergence of MDR A. baumannii.

Review Papers: Current Techniques to Detect Foot Infection in the Diabetic Patient

Diabetic foot infections can be a challenge to diagnose, especially when osteomyelitis is in question. Evaluation of infection should involve a thorough examination of the extremity for clinical signs of infection along with appropriate laboratory and imaging studies. Laboratory markers of inflammation such as peripheral leukocyte count, erythrocyte sedimentation rate, C-reactive protein, and procalcitonin may provide useful information when diagnosing soft tissue and bone infection. However, laboratory markers alone should not be used to diagnose a diabetic foot infection as they are non-specific in nature. Imaging studies may also provide valuable clues regarding the presence of infection. Plain radiographs are a good initial screening tool as they are both inexpensive and easily accessible. However, their sensitivity in diagnosing osteomyelitis is poor. Thus, more advanced imaging such as radionuclide imaging and magnetic resonance imaging are warranted when osteomyelitis is suspected. Magnetic resonance imaging is presently considered the gold standard in diagnosing osteomyelitis, despite its wide variation in reported sensitivity and specificity. However, the significant cost of magnetic resonance imaging prevents its use as a screening tool. Collection of reliable microbiologic data is critical in making a diagnosis as well as for treatment of infection, especially when osteomyelitis is concerned. Deep swabs and transcutaneous bone biopsy are considered the ideal methods of obtaining the necessary information. Finally, monitoring treatment should also be performed with an eye towards both laboratory data and the clinical exam.

Antimicrobial use in outpatient hemodialysis units.

OBJECTIVE To quantify and characterize overall antimicrobial use, including appropriateness of indication, among patients receiving chronic hemodialysis. DESIGN Retrospective and prospective observational study. SETTING Two outpatient hemodialysis units. PATIENTS All patients receiving chronic hemodialysis. METHODS The rate of parenteral antimicrobial use (number of doses per 100 patient-months) was calculated retrospectively from September 2008 through July 2011. Indication and appropriateness of antimicrobial doses were characterized prospectively from August 2010 through July 2011. Inappropriate administration was defined as occasions when criteria for infection based on national guidelines were not met, failure to choose a more narrow-spectrum antimicrobial on the basis of culture data, or occasions when indications for surgical prophylaxis were not met. RESULTS Over the 35-month retrospective study period, the rate of parenteral antimicrobial use was 32.9 doses per 100 patient-months. Vancomycin was the most commonly prescribed antimicrobial, followed by cefazolin and third- or fourth-generation cephalosporins. Over the 12-month prospective study, 1,003 antimicrobial doses were prescribed. Among the 926 (92.3%) doses for which an indication for administration was available, 276 (29.8%) were classified as inappropriate. Of these, a total of 146 (52.9%) did not meet criteria for infection, 74 (26.8%) represented failure to choose a more narrow-spectrum antimicrobial, and 56 (20.3%) did not meet criteria for surgical prophylaxis. The most common inappropriately prescribed antimicrobials were vancomycin and third- or fourth- generation cephalosporins. CONCLUSIONS Parenteral antimicrobial use was extensive, and as much as one-third was categorized as inappropriate. The findings of this study provide novel information toward minimizing inappropriate antimicrobial use.

Co-colonization with multiple different species of multidrug-resistant gram-negative bacteria

BACKGROUND The characteristics of co-colonization with multiple different species of multidrug-resistant gram-negative bacteria (MDRGN) have not been fully elucidated. Quantifying the prevalence of co-colonization and those patients at higher risk of co-colonization may have important implications for strategies aimed at limiting the spread of MDRGN. METHODS To determine the prevalence of MDRGN colonization, rectal swabs were obtained from 212 residents residing in a 600-bed long-term care facility. Co-colonization was defined as colonization with ≥2 different MDRGN species. Co-colonized residents were compared with residents colonized with a single MDRGN species to identify factors associated with an increased risk for co-colonization. Molecular typing was performed to determine the contribution of cross transmission to the co-colonized state. RESULTS A total of 53 (25%) residents was colonized with ≥1 MDRGN. Among these, 11 (21%) were colonized with ≥2 different species of MDRGN. A global deterioration score of ≥5 representing advanced dementia and an increased requirement for assistance from health care workers was significantly associated with co-colonization (P = .05). Clonally related MDRGN strains were identified among 7 (64%) co-colonized residents. CONCLUSION The prevalence of co-colonization with ≥2 different MDRGN is substantial. Cross transmission of MDRGN is a major contributor to the co-colonized state.

Diagnostic accuracy of surveillance cultures to detect gastrointestinal colonization with multidrug-resistant gram-negative bacteria

To quantify the sensitivity of surveillance cultures for the detection of multidrug-resistant gram-negative (MDRGN) bacteria, perianal/rectal swabs were collected from patients with positive clinical cultures for MDRGN species. Surveillance cultures identified colonization with the same genetically related MDRGN species in 29 of 37 MDRGN clinical culture isolates (78%). There was a trend toward less antimicrobial exposure among patients with false-negative surveillance culture results (P = .06).

Clinical Management of an Increasing Threat: Outpatient Urinary Tract Infections Due to Multidrug-Resistant Uropathogens

Urinary tract infections (UTIs) are among the most commonly treated bacterial infections. Over the past decade, antimicrobial resistance has become an increasingly common factor in the management of outpatient UTIs. As treatment options for multidrug-resistant (MDR) uropathogens are limited, clinicians need to be aware of specific clinical and epidemiological risk factors for these infections. Based on available literature, the activity of fosfomycin and nitrofurantoin remain high for most cases of MDR Escherichia coli UTIs. Trimethoprim-sulfamethoxazole retains clinical efficacy, but resistance rates are increasing internationally. Beta-lactam agents have the highest rates of resistance and lowest rates of clinical success. Fluoroquinolones have high resistance rates among MDR uropathogens and are being strongly discouraged as first-line agents for UTIs. In addition to accounting for local resistance rates, consideration of patient risk factors for resistance and pharmacological principles will help guide optimal empiric treatment of outpatient UTIs.

Novel antimicrobial-resistant bacteria among patients requiring chronic hemodialysis.

Purpose of reviewAntimicrobial-resistant bacteria (ARB) including resistant strains of Staphylococcus aureus, enterococci, and Gram-negative bacteria have the potential to cause serious infections among patients requiring chronic hemodialysis (CHD). The purpose of this article is to review novel ARB, which have emerged in this patient population, their mechanisms of transmission, and preventive efforts aimed at limiting their dissemination. Recent findingsNew strains of ARB, including community-acquired methicillin-resistant S. aureus, S. aureus strains with reduced susceptibility to vancomycin, vancomycin-resistant S. aureus and multidrug-resistant Gram-negative bacteria (MDRGN), are emerging among the CHD population. Extended-spectrum &bgr;-lactamase Gram-negative bacteria (ESBLGN) are among the most common MDRGN strains. These ESBLGN are resistant to the great majority of antimicrobials. The carbapenems remain the only optimal antimicrobial choice to treat ESBLGN infections. Intrafacility spread of ARB in dialysis units occurs between patients through contaminated hands and clothes of healthcare workers (HCWs), as well as contaminated inanimate surfaces. Spread of ARB to family members of both patients and HCWs has also been documented. SummaryColonization and infection with ARB continues to present a significant threat to patients receiving CHD. Interventions to reduce the spread of ARB should include infection control measures and judicious use of antimicrobials.

Randomized Comparison of 3 High-Level Disinfection and Sterilization Procedures for Duodenoscopes

BACKGROUND AND AIMS Duodenoscopes have been implicated in the transmission of multidrug-resistant organisms (MDRO). We compared the frequency of duodenoscope contamination with MDRO or any other bacteria after disinfection or sterilization by 3 different methods. METHODS We performed a single-center prospective randomized study in which duodenoscopes were randomly reprocessed by standard high-level disinfection (sHLD), double high-level disinfection (dHLD), or standard high-level disinfection followed by ethylene oxide gas sterilization (HLD/ETO). Samples were collected from the elevator mechanism and working channel of each duodenoscope and cultured before use. The primary outcome was the proportion of duodenoscopes with an elevator mechanism or working channel culture showing 1 or more MDRO; secondary outcomes included the frequency of duodenoscope contamination with more than 0 and 10 or more colony-forming units (CFU) of aerobic bacterial growth on either sampling location. RESULTS After 3 months of enrollment, the study was closed because of the futility; we did not observe sufficient events to evaluate the primary outcome. Among 541 duodenoscope culture events, 516 were included in the final analysis. No duodenoscope culture in any group was positive for MDRO. Bacterial growth of more than 0 CFU was noted in 16.1% duodenoscopes in the sHLD group, 16.0% in the dHLD group, and 22.5% in the HLD/ETO group (P = .21). Bacterial growth or 10 or more CFU was noted in 2.3% of duodenoscopes in the sHLD group, 4.1% in the dHLD group, and 4.2% in the HLD/ETO group (P = .36). MRDOs were cultured from 3.2% of pre-procedure rectal swabs and 2.5% of duodenal aspirates. CONCLUSIONS In a comparison of duodenoscopes reprocessed by sHLD, dHLD, or HLD/ETO, we found no significant differences between groups for MDRO or bacteria contamination. Enhanced disinfection methods (dHLD or HLD/ETO) did not provide additional protection against contamination. However, insufficient events occurred to assess our primary study end-point. ClinicalTrials.gov no: NCT02611648.

Predominance of Lactobacillus spp. Among Patients Who Do Not Acquire Multidrug-Resistant Organisms

BACKGROUND The emergence and dissemination of multidrug-resistant organisms (MDROs) is a global threat. Characterizing the human microbiome among hospitalized patients and identifying unique microbial signatures among those patients who acquire MDROs may identify novel infection prevention strategies. METHODS Adult patients admitted to 5 general medical-surgical floors at a 649-bed, tertiary care center in Boston, Massachusetts, were classified according to in-hospital antimicrobial exposure and MDRO colonization status. Within 48 hours of hospital admission (baseline) and at discharge (follow-up), rectal swab samples were obtained, and compared with samples from an external control group of healthy persons from the community. DNA was extracted from samples, next-generation sequencing performed, and microbial community structure and taxonomic features assessed, comparing those who acquired MDROs and those who had not, and the external controls. RESULTS Hospitalized patients (n = 44) had reduced microbial diversity and a greater abundance of Escherichia spp. and Enterococcus spp. than healthy controls (n = 26). Among hospitalized patients, 25 had no MDROs at the time of the baseline sample and were also exposed to antimicrobials. Among this group, 7 (28%) acquired ≥1 MDRO; demographic and clinical characteristics were similar between MDRO-acquisition and MDRO-nonacquisition groups. Patients in the nonacquisition group had consistently higher Lactobacillus spp. abundance than those in the acquisition group (linear discriminant score, 3.97; P = .04). CONCLUSIONS The fecal microbiota of the hospitalized subjects had abnormal community composition, and Lactobacillus spp. was associated with lack of MDRO acquisition, consistent with a protective role.

Effectiveness of visual inspection compared with non-microbiologic methods to determine the thoroughness of post-discharge cleaning

BackgroundPublished data to date have provided a limited comparison between non-microbiologic methods—particularly visual inspection—and a microbiologic comparator to evaluate the effectiveness of environmental cleaning of patient rooms. We sought to compare the accuracy of visual inspection with other non-microbiologic methods of assessing the effectiveness of post-discharge cleaning (PDC).MethodsProspective evaluation to determine the effectiveness of PDC in comparison to a microbiologic comparator. Using a highly standardized methodology examining 15 high-touch surfaces, the effectiveness of PDC was evaluated by visual inspection, the removal of fluorescent marker (FM) placed prior to room occupancy, quantification of adenosine triphosphate (ATP) levels, and culture for aerobic colony counts (ACC).ResultsTwenty rooms including 293 surfaces were sampled in the study, including 290 surfaces sampled by all four methods. ACC demonstrated 72% of surfaces to be microbiologically clean. Visual inspection, FM, ATP demonstrated 57%, 49%, and 66% of surfaces to be clean. Using ACC as a microbiologic comparator, the sensitivity of visual inspection, FM, and ATP to detect a clean surface were 60%, 51%, and 70%, respectively; the specificity of visual inspection, FM, and ATP were 52%, 56%, and 44%.ConclusionsIn assessing the effectiveness of PDC, there was poor correlation between the two most frequently studied commercial methods and a microbiologic comparator. Visual inspection performed at least as well as commercial methods, directly addresses patient perception of cleanliness, and is economical to implement.