To determine the rates of and risk factors for tigecycline nonsusceptibility among carbapenem-resistant Klebsiella pneumoniae (CRKPs) isolated from hospitalized patients

Multicenter prospective observational study

Acute care hospitals participating in the Consortium on Resistance against Carbapenems in Klebsiella pneumoniae (CRaCKle)

A cohort of 287 patients who had CRKPs isolated from clinical cultures during hospitalization

For the period from December 24, 2011 to October 1, 2013, the first hospitalization of each patient with a CRKP during which tigecycline susceptibility for the CRKP isolate was determined was included. Clinical data were entered into a centralized database, including data regarding pre-hospital origin. Breakpoints established by the European Committee on Antimicrobial Susceptibility Testing (EUCAST) were used to interpret tigecycline susceptibility testing.

Of 287 patients included in the final cohort, 155 (54%) had tigecycline-susceptible CRKPs. Of all index isolates, 81 (28%) were tigecycline-intermediate and 51 (18%) were tigecycline resistant. In multivariate modeling, independent risk factors for tigecycline nonsusceptibility were (1) admission from a skilled nursing facility (OR, 2.51; 95% CI, 1.51–4.21; P=.0004), (2) positive culture within 2 days of admission (OR, 1.82; 95% CI, 1.06–3.15; P=.03), and (3) receipt of tigecycline within 14 days (OR, 4.38, 95% CI, 1.37–17.01, P=.02).

In hospitalized patients with CRKPs, tigecycline nonsusceptibility was more frequently observed in those admitted from skilled nursing facilities and occurred earlier during hospitalization. Skilled nursing facilities are an important target for interventions to decrease antibacterial resistance to antibiotics of last resort for treatment of CRKPs.

Infect Control Hosp Epidemiol 2015;36(8):942–948

To compare Pseudomonas aeruginosa prevalence in electronic and manual faucets and assess the influence of connecting pipes and water quality.

Faucets in 4 healthcare centers in Quebec, Canada.

Water samples from 105 electronic, 90 manual, and 14 foot-operated faucets were analyzed for P. aeruginosa by culture and enzymatic detection, and swab samples from drains and aerators were analyzed by culture. Copper and residual chlorine concentrations, temperature, and flow rate were measured. P. aeruginosa concentrations were analyzed in 4 consecutive volumes of cold water and a laboratory study was conducted on copper pipes and flexible hoses.

P. aeruginosa contamination was found in drains more frequently (51%) than in aerators (1%) or water (culture: 4%, enzyme detection: 16%). Prevalence in water samples was comparable between manual (14%) and 2 types of electronic faucets (16%) while higher for foot-operated faucets (29%). However, type 2 electronic faucets were more often contaminated (31%) than type 1 (14%), suggesting that faucet architecture and mitigated volume (30 mL vs 10 mL) influence P. aeruginosa growth. Concentrations were 100 times higher in the first 250 mL than after flushing. Flexible hoses were more favorable to P. aeruginosa growth than copper and a temperature of 40°C led to higher counts.

The types of faucets and connecting pipes, flow rate, and water quality are important parameters influencing the prevalence and the concentrations of P. aeruginosa in faucets. High concentrations of P. aeruginosa in the first 250 mL suggest increased risk of exposure when using the first flush.

Infect Control Hosp Epidemiol 2014;00(0): 1–9

To determine the potential epidemiologic and economic value of the implementation of a multifaceted Clostridium difficile infection (CDI) control program at US acute care hospitals

Markov model with a 5-year time horizon

Patients whose data were used in our simulations were limited to hospitalized Medicare beneficiaries ≥65 years old.

CDI is an important public health problem with substantial associated morbidity, mortality, and cost. Multifaceted national prevention efforts in the United Kingdom, including antimicrobial stewardship, patient isolation, hand hygiene, environmental cleaning and disinfection, and audit, resulted in a 59% reduction in CDI cases reported from 2008 to 2012.

Our analysis was conducted from the federal perspective. The intervention we modeled included the following components: antimicrobial stewardship utilizing the Antimicrobial Use and Resistance module of the National Healthcare Safety Network (NHSN), use of contact precautions, and enhanced environmental cleaning. We parameterized our model using data from CDC surveillance systems, the AHRQ Healthcare Cost and Utilization Project, and literature reviews. To address uncertainty in our parameter estimates, we conducted sensitivity analyses for intervention effectiveness and cost, expenditures by other federal partners, and discount rate. Each simulation represented a cohort of 1,000 hospitalized patients over 1,000 trials.

In our base case scenario with 50% intervention effectiveness, we estimated that 509,000 CDI cases and 82,000 CDI-attributable deaths would be prevented over a 5-year time horizon. Nationally, the cost savings across all hospitalizations would be $2.5 billion (95% credible interval: $1.2 billion to $4.0 billion).

The potential benefits of a multifaceted national CDI prevention program are sizeable from the federal perspective.

Infect Control Hosp Epidemiol 2015;00(0): 1–7

Rapidly growing nontuberculous mycobacteria (RGM) are considered rare pathogens, causing central line–associated bloodstream infection. We identified an outbreak of central line–associated bloodstream infection due to RGM at a hematology-oncology ward during a 5-month period.

Outbreak investigation and literature review.

A Japanese tertiary care center.

Adults who were hospitalized at the hematology-oncology ward from October 15, 2011, through February 17, 2012.

A total of 5 patients with a bloodstream infection due to RGM (4 cases of Mycobacterium mucogenicum and 1 case of Mycobacterium canariasense infection) were identified; of these, 3 patients had acute myeloid leukemia, 1 had acute lymphocytic leukemia, and 1 had aplastic anemia. Four of the 5 patients received cord blood transplantation prior to developing the bloodstream infection. All central venous catheters in patients with a bloodstream infection were removed. These patients promptly defervesced after catheter removal and their care was successfully managed without antimicrobial therapy. Surveillance cultures from the environment and water detected M. mucogenicum and M. canariasense in the water supply of the hematology-oncology ward. The isolates from the bloodstream infection and water sources were identical on the basis of 16S-rRNA gene sequencing.

The source of RGM in the outbreak of bloodstream infections likely was the ward tap water supply. Awareness of catheter-related bloodstream infections due to nontuberculous mycobacteria should be emphasized, especially where immunocompromised patients are at risk. Also, using antimicrobials after catheter removal to treat central line–associated bloodstream infection due to RGM may not be necessary.

Infect Control Hosp Epidemiol 2015;36(1): 76–80

The molecular epidemiology of pediatric Clostridium difficile infection (CDI) is poorly understood. We aimed to identify the restriction endonuclease analysis (REA) groups causing CDI and to determine risk factors and outcomes associated with CDI caused by epidemic strains in children.

Retrospective cohort study

Inpatients and outpatients >1 year old receiving care between December 2012 and December 2013

An academic children’s hospital in Chicago, Illinois

C. difficile PCR-positive stools were cultured, and C. difficile isolates were typed by REA. REA of isolates from patients with multiple CDIs was performed to differentiate relapse (infection with same strain) from reinfection (different strains) irrespective of time between CDIs.

A total of 189 CDIs occurred among 145 patients. REA groups were widely distributed. The BI/NAP1/027 strain caused CDI in only 1 patient. DH/NAP11/106, the predominant epidemic strain identified, was associated with the use of third- or fourth-generation cephalosporins (risk ratio [RR], 3.2; 95% confidence interval [CI], 1.1–9.9; P=.04). CDI relapse commonly occurred up to 20 weeks later. Compared with CDI caused by non-DH/NAP11/106 strains, CDI caused by DH/NAP11/106 was more likely to result in multiple CDI relapses (40% vs 8%; P=.05) among children with multiple CDIs.

REA identified the exceedingly low prevalence of BI/NAP1/027 and the high prevalence of DH/NAP11/106, a common epidemic strain in the United Kingdom that is less often reported in the United States. CDI relapse commonly occurred up to 20 weeks from the previous CDI. Defining recurrent CDI as that occurring only within 8 weeks of the original infection may lead to misclassification of some recurrent CDIs as new CDIs in children.

Infect Control Hosp Epidemiol 2015;00(0): 1–7

Clostridium difficile infection (CDI) in hospitalized patients is generally attributed to the current stay, but recent studies reveal high C. difficile colonization rates on admission.

To determine the rate of colonization with toxigenic C. difficile among intensive care unit patients upon admission as well as acquired during hospitalization, and the risk of subsequent CDI.

Prospective cohort study from April 15 through July 8, 2013. Adults admitted to an intensive care unit within 48 hours of admission to the Johns Hopkins Hospital, Baltimore, Maryland, were screened for colonization with toxigenic C. difficile. The primary outcome was risk of developing CDI.

Among 542 patients, 17 (3.1%) were colonized with toxigenic C. difficile on admission and an additional 3 patients were found to be colonized during hospitalization. Both colonization with toxigenic C. difficile on admission and colonization during hospitalization were associated with an increased risk for development of CDI (relative risk, 10.29 [95% CI, 2.24–47.40], P=.003; and 15.66 [4.01–61.08], P<.001, respectively). Using multivariable analysis, colonization on admission and colonization during hospitalization were independent predictors of CDI (relative risk, 8.62 [95% CI, 1.48–50.25], P=.017; and 10.93 [1.49–80.20], P=.019, respectively), while adjusting for potential confounders.

In intensive care unit patients, colonization with toxigenic C. difficile is an independent risk factor for development of subsequent CDI. Further studies are needed to identify populations with higher toxigenic C. difficile colonization rates possibly benefiting from screening or avoidance of agents known to promote CDI.

Infect. Control Hosp. Epidemiol. 2015;36(11):1324–1329

To understand the professional and psychosocial factors that influence physician antibiotic prescribing habits in the inpatient setting.

We conducted semi-structured interviews with 30 inpatient physicians. Interviews consisted of open-ended questions and flexible probes based on participant responses. Interviews were audio recorded, transcribed, de-identified, and reviewed for accuracy and completeness. Data were analyzed using emergent thematic analysis.

Two teaching hospitals in Indianapolis, Indiana

A total of 30 inpatient physicians (10 physicians-in-training, 20 supervising staff) were enrolled in this study.

Participants recognized that antibiotics are overused, and many admitted to prescribing antibiotics even when the clinical evidence of infection was uncertain. Overprescription was largely driven by anxiety about missing an infection, whereas potential adverse effects of antibiotics did not strongly influence decision making. Participants did not routinely disclose potential adverse effects of antibiotics to inpatients. Physicians-in-training were strongly influenced by the antibiotic prescribing behavior of their supervising staff physicians. Participants sometimes questioned their colleagues’ antibiotic prescribing decisions, but they frequently avoided providing direct feedback or critique. These physicians cited obstacles of hierarchy, infrequent face-to-face encounters, and the awkwardness of these conversations.

A physician-based culture of prescribing antibiotics involves overusing antibiotics and not challenging the decisions of colleagues. The potential adverse effects of antibiotics did not strongly influence decision making in this sample. A better understanding of these factors could be leveraged in future efforts to improve antibiotic prescribing practices in the inpatient setting.

Infect. Control Hosp. Epidemiol. 2015;36(9):1065–1072

Healthcare-associated infection rates are higher in low- and middle-income countries compared with high-income countries, resulting in relatively larger incidence of patient mortality and disability and additional healthcare costs.

To use the Infection Control Assessment Tool to assess gaps in infection control (IC) practices in the participating countries.

Six international sites located in Argentina, Greece, Hungary, India, Nepal, and South Africa provided information on the health facility and the surgical modules relating to IC programs, surgical antibiotic use and surgical equipment procedures, surgical area practices, sterilization and disinfection of equipment and intravenous fluid, and hand hygiene. Modules were scored for each country.

The 6 international sites completed 5 modules. Of 121 completed sections, scores of less than 50% of the recommended IC practices were received in 23 (19%) and scores from 50% to 75% were received in 43 (36%). IC programs had various limitations in many sites and surveillance of healthcare-associated infections was not consistently performed. Lack of administration of perioperative antibiotics, inadequate sterilization and disinfection of equipment, and paucity of hand hygiene were found even in a high-income country. There was also a lack of clearly written defined policies and procedures across many facilities.

Our results indicate that adherence to recommended IC practices is suboptimal. Opportunities for improvement of IC practices exist in several areas, including hospital-wide IC programs and surveillance, antibiotic stewardship, written and posted guidelines and policies across a range of topics, surgical instrument sterilization procedures, and improved hand hygiene.

Infect. Control Hosp. Epidemiol. 2015;36(10):1208–1214

To identify the source of a pseudo-outbreak of Mycobacterium gordonae

Outbreak investigation.

University Hospital in Chicago, Ilinois.

Hospital patients with M. gordonae-positive clinical cultures.

An increase in isolation of M. gordonae from clinical cultures was noted immediately following the opening of a newly constructed hospital in January 2012. We reviewed medical records of patients with M. gordonae-positive cultures collected between January and December 2012 and cultured potable water specimens in new and old hospitals quantitatively for mycobacteria.

Of 30 patients with M. gordonae-positive clinical cultures, 25 (83.3%) were housed in the new hospital; of 35 positive specimens (sputum, bronchoalveolar lavage, gastric aspirate), 32 (91.4%) had potential for water contamination. M. gordonae was more common in water collected from the new vs. the old hospital [147 of 157 (93.6%) vs. 91 of 113 (80.5%), P=.001]. Median concentration of M. gordonae was higher in the samples from the new vs. the old hospital (208 vs. 48 colony-forming units (CFU)/mL; P<.001). Prevalence and concentration of M. gordonae were lower in water samples from ice and water dispensers [13 of 28 (46.4%) and 0 CFU/mL] compared with water samples from patient rooms and common areas [225 of 242 (93%) and 146 CFU/mL, P<.001].

M. gordonae was common in potable water. The pseudo-outbreak of M. gordonae was likely due to increased concentrations of M. gordonae in the potable water supply of the new hospital. A silver ion-impregnated 0.5-μm filter may have been responsible for lower concentrations of M. gordonae identified in ice/water dispenser samples. Hospitals should anticipate that construction activities may amplify the presence of waterborne nontuberculous mycobacterial contaminants.

Infect Control Hosp Epidemiol 2014;00(0): 1–6

An estimated 20–30% of patients with primary Clostridium difficile infection (CDI) develop recurrent CDI (rCDI) within 2 weeks of completion of therapy. While the actual mechanism of recurrence remains unknown, a variety of risk factors have been suggested and studied. The aim of this systematic review and meta-analysis was to evaluate current evidence on the risk factors for rCDI.

We searched MEDLINE and 5 other databases for subject headings and text related to rCDI. All studies investigating risk factors of rCDI in a multivariate model were eligible. Information on study design, patient population, and assessed risk factors were collected. Data were combined using a random-effects model and pooled relative risk ratios (RRs) were calculated.

A total of 33 studies (n=18,530) met the inclusion criteria. The most frequent independent risk factors associated with rCDI were age≥65 years (risk ratio [RR], 1.63; 95% confidence interval [CI], 1.24–2.14; P=.0005), additional antibiotics during follow-up (RR, 1.76; 95% CI, 1.52–2.05; P<.00001), use of proton-pump inhibitors (PPIs) (RR, 1.58; 95% CI, 1.13–2.21; P=.008), and renal insufficiency (RR, 1.59; 95% CI, 1.14–2.23; P=.007). The risk was also greater in patients previously on fluoroquinolones (RR, 1.42; 95% CI, 1.28–1.57; P<.00001).

Multiple risk factors are associated with the development of rCDI. Identification of modifiable risk factors and judicious use of antibiotics and PPI can play an important role in the prevention of rCDI.

Infect Control Hosp Epidemiol 2015;00(0): 1–9

To identify risk factors related to Mycobacterium abscessus subsp. bolletii infection during an outbreak, associated with laparoscopic surgery and to propose recommendations for preventing new cases.

A retrospective cohort study.

A private hospital in Manaus, Brazil.

A cohort of 222 patients who underwent laparoscopic surgery between July 2009 and August 2010 by a single surgical team.

We collected information about the patients and the surgical procedure using a standard form. We included sex, age, and variables with P≤0.2 in the bivariate analysis in a logistic regression model. Additionally, we reviewed the procedures for reprocessing the laparoscopic surgery equipment, and the strains obtained with culture were identified by molecular methods.

We recorded 60 (27%) cases of infection. After multivariate analysis, the duration of surgery beyond 1 hour (odds ratio [OR] 2.4; 95% confidence interval [CI] 1.2–4.5), not to have been the first operated patient on a given day (OR, 2.7; 95% CI, 1.4–5.2), and the use of permanent trocar (OR, 2.2; 95% CI, 1.1–4.2) were associated with infection. We observed that the surgical team attempted to sterilize the equipment in glutaraldehyde solution when sanitary authorities had already prohibited it. Eleven strains presented 100% DNA identity with a single strain, known as BRA100 clone.

Because contaminated material can act as vehicle for infection, ensuring adequate sterilization processing of video-assisted surgery equipment was crucial to stopping this single clonal outbreak of nonturbeculous mycobacteria in Brazil.

Infect Control Hosp Epidemiol 2015;36(1): 81–86

To systematically review studies evaluating clinical prediction rules (CPRs) for adult inpatients suspected to have pulmonary tuberculosis.

Systematic review with meta-analyses.

Hospitals.

Inpatients at least 15 years of age admitted to acute care.

A search was conducted in 5 indexed electronic databases with no language or year of publication restrictions. We performed a meta-analysis for those CPRs with at least 2 validation studies. Results were reported according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses.

Of the 461 abstracts selected, 36 articles were fully analyzed and 11 articles were included, yielding 8 CPRs derived in 4 countries. Broad validation studies were identified for 2 CPRs. The most frequent clinical predictors were fever and weight loss. All CPRs included chest imaging signs. Most CPRs were derived in countries with a low prevalence of pulmonary tuberculosis and included homeless, immigrants, and those who reacted to the purified protein derivative test. Both of the CPRs derived in countries with a high prevalence of pulmonary tuberculosis strongly relied on chest radiograph predictors. Accuracy of the different CPRs was high (area under receiver operating characteristic curve, 0.79–0.91). Meta-analysis of 4 validation studies for Wisnivesky´s CPR indicates optimistic pooled results: sensitivity, 94.1% (95% CI, 89.7%–96.7%); negative likelihood ratio, 0.22 (95% CI, 0.12–0.40).

On the basis of a critical appraisal of the 2 best validated CPRs, the presence of weight loss and/or fever in inpatients warrants obtaining a chest radiograph, regardless of the presence of productive cough. If the chest radiograph is abnormal, the patient should be placed in isolation until more specific test results are available. Validation in different settings is required to maximize external generalization of existing CPRs.

Infect Control Hosp Epidemiol 2014;00(0): 1–10

We found previously that inappropriate inpatient antimicrobial use was often attributable to erroneous diagnoses. Here, we detail diagnostic errors and their relationship to inappropriate antimicrobial courses.

Retrospective cohort study

Veterans Affairs hospital

A cohort of 500 randomly selected inpatients with an antimicrobial course

Blinded reviewers judged the accuracy of the initial provider diagnosis for the condition that led to an antimicrobial course and whether the course was appropriate.

The diagnoses were correct in 291 cases (58%), incorrect in 156 cases (31%), and of indeterminate accuracy in 22 cases (4%). In the remaining 31 cases (6%), the diagnosis was a sign or symptom rather than a syndrome or disease. The odds ratio of a correct diagnosis was 4.3 (95% confidence interval [CI], 2.2–8.5) if the index condition was related to the reason for admission. When the diagnosis was correct, 181 of 292 courses (62%) were appropriate, compared with only 10 of 208 (5%) when the diagnosis was incorrect or indeterminate or when providers were treating a sign or symptom rather than a syndrome or disease (P<.001). Among the 309 cases in which antimicrobial courses were not appropriate, reasons varied by diagnostic accuracy; in 81 of 111 cases (73%) with a correct diagnosis, incorrect antimicrobial(s) were selected; in 166 of 198 other cases (84%), antimicrobial therapy was not indicated.

Diagnostic accuracy is important for optimal inpatient antimicrobial use. Antimicrobial stewardship strategies should help providers avoid diagnostic errors and know when antimicrobial therapy can be withheld safely.

Infect Control Hosp Epidemiol 2015;36(8):949–956