Preventing Transmission of Multidrug-Resistant Bacteria in Health Care Settings: A Tale of Two Guidelines

Prevention of the spread of multidrug-resistant organisms in nursing homes

The increase in the aged population led to a global rise in the demand for elderly healthcare services, such as long-term care facilities (LTCFs), nursing homes, residential homes. Unfortunately, the spread of multidrug-resistant organisms (MDROs) in these structures represent an urgent public health threat requiring immediate action. The aim of this review is to provide a practice guide for the prevention of infections in European LTCFs. A team of experts identify specific problems and proposed practical solutions for the management of colonized and infected patients residing in LTCFs. The heterogeneity of LTCF represents one of the main problems for the implementation of standardized surveillance and infection control programs. Crucial steps involved in the spread of infections among LTCF residents are represented by patient's accommodation, MDRO screening on admission, management of patients with rectal colonization by MDROs, management of patients at high risk of MDRO infections, MDRO transmission by staff and implementation of antimicrobial stewardship. Efforts to implement specific actions in each of these fields are required to reduce the infections in this setting.

Role of surveillance cultures in infection control

Hospital-acquired infections are a known menace to the primary disease, for which a patient is admitted. These infections are twenty times more common in developing countries than in the developed ones. Surveillance for colonised patients can be passive or active process. In many hospitals, active surveillance culture for certain sentinel organisms followed by contact precautions for the same is an important part of infection control policy. Specific measures can be taken on early detection of multidrug-resistant organism, allowing prevention of widespread transmission in hospitals. Cultures are the most conventional and economical microbiological method of detection. The cost of active surveillance is a major challenge, especially for developing nations. These nations lack basic infrastructure and have logistic issues. The guidelines regarding this are not very clearly delineated for developing countries. Each hospital has its own challenges and the process is to be tailor-made accordingly. The following review delineates the various aspects of active surveillance for the colonisation of various organisms and the advantages and disadvantages of the same.

A broad-spectrum beta-lactam-sparing stewardship program in a middle-income country public hospital: antibiotic use and expenditure outcomes and antimicrobial susceptibility profiles

Background

Antimicrobial stewardship programs are an efficient way to reduce inappropriate use of antimicrobials and costs; however, supporting data are scarce in middle-income countries. The aim of this study was to evaluate antibiotic use, bacterial susceptibility profiles, and the economic impact following implementation of a broad-spectrum beta-lactam-sparing antimicrobial stewardship program.

Methods

An interrupted time-series analysis was performed to evaluate antibiotic use and expenditure over a 24-month period (12 months before the antimicrobial stewardship program and in the 12 months after implementation of the antimicrobial stewardship program). Antibiotics were classified into one of two groups: beta-lactam antibiotics and beta-lactam-sparing antibiotics. We also compared the antimicrobial susceptibility profiles of key pathogens in each period.

Results

Beta-lactam antibiotics use decreased by 43.04 days of therapy/1000 patient-days (p = 0.04) immediately following antimicrobial stewardship program implementation, whereas beta-lacta-sparing antibiotics use increased during the intervention period (slope change 6.17 days of therapy/1000 patient-days, p < 0.001). Expenditure decreased by $2089.99 (p < 0.001) immediately after intervention and was maintained at this level over the intervention period ($−38.45; p = 0.24). We also observed that a greater proportion of pathogens were susceptible to cephalosporins and aminoglycosides after the antimicrobial stewardship program.

Conclusions

The antimicrobial stewardship program significantly reduced the use of broad-spectrum beta-lactam-antibiotics associated with a decrease in expenditure and maintenance of the susceptibility profile in Gram-negative bacteria.

Real-time surveillance systems: Applicability for the control of influenza in acute care

Background

The high morbidity and mortality caused by influenza viruses translate into a great impact on specialized health care. Apart from the annual vaccination, the relevance of other measures to prevent and control this infection is unknown. The objective of our research was to determine the importance of a real‐time surveillance system to establish early extended transmission precautions.

Methods

Quasi‐experimental before‐and‐after study comparing the influenza cases detected in hospitalized adults during the 2016/2017 season (264 patients) with those detected after the implementation of a real‐time surveillance system in the 2017/2018 season (519 patients). The improvements included early microbiological diagnosis, immediate communication of results, constant updating of patient information, coordination among professionals, periodic surveillance of the adequacy of preventive measures, and greater control of roommates. The effectiveness of the intervention was determined from the nosocomial infection rate in each season.

Results

After the real‐time surveillance system for influenza was implemented, patients with early microbiological diagnosis and immediate isolation increased significantly (13.7% vs 68.2%; P < .001). In addition, nosocomial infections decreased from 17% to 9.2% (P = .001) and overall hospital stay was significantly reduced. Assuming that the entire effect was due to the intervention, the absolute risk reduction was 7.8% and number needed to treat was 12.8.

Conclusion

The results in our study reveal the impact of nosocomial transmission of influenza virus in a tertiary hospital and highlight the need to supplement traditional strategies with novel methodologies such as modern surveillance systems based on early diagnosis, close case monitoring, and coordination among professionals.

What To Think If the Results of the National Institutes of Health Randomized Trial of Methicillin-ResistantStaphylococcus aureusand Vancomycin-ResistantEnterococcusControl Measures Are Negative (and Other Advice to Young Epidemiologists): A Review and an Au Revoir

The incidence of methicillin-resistantStaphylococcus aureus(MRSA) and vancomycin-resistantEnterococcus(VRE) infections continues to rise in National Nosocomial Infections Surveillance system hospitals, and these pathogens are reportedly causing more than 100,000 infections and many deaths each year in US healthcare facilities. This has led some to insist that control measures are now urgently needed, but several recent articles have suggested that isolation of patients does not work, is not needed, or is unsafe, or that a single cluster-randomized trial could be used to decide such matters. At least 101 studies have reported controlling MRSA infection and 38 have reported controlling VRE infection by means of active detection by surveillance culture and use of isolation for all colonized patients in healthcare settings where the pathogens are epidemic or endemic, in academic and nonacademic hospitals, and in acute care, intensive care, and long-term care settings. MRSA colonization and infection have been controlled to exceedingly low levels in multiple nations and in the state of Western Australia for decades by use of active detection and isolation. Studies suggesting problems with using such data to control MRSA colonization and infection have their own problems, which are discussed. Randomized trials are epidemiologic tools that can sometimes provide erroneous results, and they have not been considered necessary for studying isolation before it is used to control other important infections, such as tuberculosis, smallpox, and severe acute respiratory syndrome. No single epidemiologic study should be considered definitive. One should always weigh all available evidence. Infection with antibiotic-resistant pathogens such as MRSA and VRE is controllable to a low level by active detection and isolation of colonized and infected patients. Effective measures should be used to minimize the morbidity and mortality attributable to these largely preventable infections.

Contact Precautions More Is Not Necessarily Better

Objective.

To determine whether increases in contact isolation precautions are associated with decreased adherence to isolation practices among healthcare workers (HCWs).

Design.

Prospective cohort study from February 2009 to October 2009.

Setting.

Eleven teaching hospitals.

Participants.

HCWs.

Methods.

One thousand thirteen observations conducted on HCWs. Additional data included the number of persons in isolation, types of HCWs, and hospital-specific contact precaution practices. Main outcome measures included compliance with individual components of contact isolation precautions (hand hygiene before and after patient encounter, donning of gown and glove upon entering a patient room, and doffing upon exiting) and overall compliance (all 5 measures together) during varying burdens of isolation.

Results.

Compliance with hand hygiene was as follows: prior to donning gowns/gloves, 37.2%; gowning, 74.3%; gloving, 80.1%; doffing of gowns/gloves, 80.1%; after gown/glove removal, 61%. Compliance with all components was 28.9%. As the burden of isolation increased (20% or less to greater than 60%), a decrease in compliance with hand hygiene (43.6%—4.9%) and with all 5 components (31.5%—6.5%) was observed. In multivariable analysis, there was an increase in noncompliance with all 5 components of the contact isolation precautions bundle (odds ratio [OR], 6.6 [95% confidence interval (CI), 1.15-37.44];P= .03) and in noncompliance with hand hygiene prior to donning gowns and gloves (OR, 10.1 [95% CI, 1.84—55.54];P= .008) associated with increasing burden of isolation.

Conclusions.

As the proportion of patients in contact isolation increases, compliance with contact isolation precautions decreases. Placing 40% of patients under contact precautions represents a tipping point for noncompliance with contact isolation precautions measures.

Infection Prevention and Control Guideline for Cystic Fibrosis: 2013 Update

The 2013 Infection Prevention and Control (IP&C) Guideline for Cystic Fibrosis (CF) was commissioned by the CF Foundation as an update of the 2003 Infection Control Guideline for CF. During the past decade, new knowledge and new challenges provided the following rationale to develop updated IP&C strategies for this unique population:

1.The need to integrate relevant recommendations from evidence-based guidelines published since 2003 into IP&C practices for CF. These included guidelines from the Centers for Disease Control and Prevention (CDC)/Healthcare Infection Control Practices Advisory Committee (HICPAC), the World Health Organization (WHO), and key professional societies, including the Infectious Diseases Society of America (IDSA) and the Society for Healthcare Epidemiology of America (SHEA). During the past decade, new evidence has led to a renewed emphasis on source containment of potential pathogens and the role played by the contaminated healthcare environment in the transmission of infectious agents. Furthermore, an increased understanding of the importance of the application of implementation science, monitoring adherence, and feedback principles has been shown to increase the effectiveness of IP&C guideline recommendations.

2.Experience with emerging pathogens in the non-CF population has expanded our understanding of droplet transmission of respiratory pathogens and can inform IP&C strategies for CF. These pathogens include severe acute respiratory syndrome coronavirus and the 2009 influenza A H1N1. Lessons learned about preventing transmission of methicillin-resistantStaphylococcus aureus(MRSA) and multidrug-resistant gram-negative pathogens in non-CF patient populations also can inform IP&C strategies for CF.

Effectiveness of contact precautions against multidrug-resistant organism transmission in acute care: a systematic review of the literature

Contact precautions are widely recommended to prevent multidrug-resistant organism (MDRO) transmission. However, conflicting data exist regarding their effectiveness. Prior systematic reviews examined contact precautions as part of a larger bundled approach, limiting ability to understand their effectiveness. The aim of this review was to characterize the effectiveness of contact precautions alone against transmission of any MDRO among adult acute care patients. Directed by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement, comprehensive searches of four electronic scientific literature databases were conducted for studies published in English from January 2004 to June 2014. Studies were included if interventional, original research, evaluating contact isolation precautions against MDRO transmission among inpatients. Searches returned 284 studies, six of which were included in the review. These studies measured four different MDROs with one study showing a reduction in transmission. Whereas studies were of high quality regarding outcome operationalization and statistical analyses, overall quality was moderate to low due to poor intervention description, population characterization and potential biases. Where compliance was measured (N = 4), it presented a threat to validity because it included select parts of the intervention, ranged from 21% to 87%, and was significantly different across study phases (N = 2). The poor quality of evidence on this topic continues to limit interpretation of these data. Hence, this conflicting body of literature does not constitute evidence for or against contact precautions. We recommend that researchers consider power calculation, compliance monitoring, non-equivalent concurrent controls when designing future studies on this topic.

Political Versus Epidemiological Correctness

In the March issue of the journal, the Joint SHEA and APIC Task Force indicates that the Society for Healthcare Epidemiology of America (SHEA) and the Association for Professionals in Infection Control and Epidemiology (APIC) support the use of active detection and isolation (ADI) for controlling nosocomial infections due to methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus (VRE) “in appropriate circumstances, as recommended in previously published guidelines”1(p250) (those published by SHEA and the Healthcare Infection Control Practices Advisory Committee [HICPAC]), but that SHEA and APIC oppose the use of legislation for mandating any infection control approach, including this one as tried in 2006 in Illinois and Maryland.

Both supporters and opponents of controlling MRSA and VRE with ADI probably will agree that legislation is not the optimal way to control nosocomial infections in general, but this position statement undoubtedly will please the latter more than it does the former because the SHEA/APIC Task Force argues that ADI is not ready for routine use throughout all healthcare facilities, directly opposing the position of the original SHEA guideline. As an author of that SHEA guideline, I would like to comment. First, the new position seems politically correct (since most infection control professionals have not yet bothered using ADI to control MRSA and VRE), but many of the planks of the SHEA/APIC Task Force position statement are misleading.

Assessment of five screening strategies for optimal detection of carriers of third-generation cephalosporin-resistant Enterobacteriaceae in intensive care units using daily sampling

There is no consensus on optimal screening procedures for multidrug-resistant Enterobacteriaceae (MDRE) in intensive care units (ICUs). Therefore, we assessed five strategies for the detection of extended-spectrum beta-lactamase (ESBL) and high-level expressed AmpC cephalosporinase (HL-CASE) producers. During a 3-month period, a rectal screening swab sample was collected daily from every ICU patient, from the first 24 h to the last day of ICU stay. Samples were plated on MDRE-selective media. Bacteria were identified using MALDI-TOF mass spectrometry and antibiograms were performed using disk diffusion. MDREs were isolated from 682/2348 (29.0%) screening samples collected from 93/269 (34.6%) patients. Incidences of patients with ESBL and HL-CASE producers were 17.8 and 19.3 per 100 admissions, respectively. In 48/93 patients, MDRE carriage was intermittent. Compared with systematic screening at admission, systematic screening at discharge did not significantly increase the rate of MDRE detection among the 93 patients (62% vs. 70%). In contrast, screening at admission and discharge, screening at admission and weekly thereafter, and screening at admission and weekly thereafter and at discharge significantly increased MDRE detection (77%, p 0.02; 76%, p 0.01; 86%, p<0.001, respectively). The difference in MDRE detection between these strategies relies essentially on the levels of detection of patients with HL-CASE producers. The most reasonable strategy would be to collect two samples, one at admission and one at discharge, which would detect 87.5% of the ESBL strains, 67.3% of the HL-CASE strains and 77.4% of all MDRE strains. This study should facilitate decision-making concerning the most suitable screening policy for MDRE detection in a given ICU setting.

Risk factors for urinary tract infection with multiple drug-resistant Escherichia coli in cats

The emergence of multiple drug-resistant (MDR) bacteria is a growing public health problem. The objective of this retrospective study was to identify risk factors associated with MDR Escherichia coli infection of the urinary tract in cats. All cats presenting with an E coli urinary infection between March 2010 and December 2012 were included and divided into two groups: an MDR group and a non-MDR group. The effects of different variables on the occurrence of an MDR E coli infection were evaluated: age, sex, additional diseases, number of antibiotics and number of days of hospitalisation. Fifty-two cats were identified (10 MDR and 42 non-MDR). The number of antibiotic groups used within the last 3 months was associated with an increased risk of MDR E coli urinary infection (P = 0.007). The association of the number of days of hospitalisation within the last 3 months and the increased risk of MDR E coli urinary infection did not reach significance (P = 0.090). This study provides evidence that systematic urinary culture with antibiotic sensitivity testing should be recommended when treating urinary tract infections if antibiotics have been prescribed within the past 3 months. Moreover, the selection of MDR bacteria through antibiotic use should be considered as a potential risk associated with treatment.

Surveillance and management of multidrug-resistant microorganisms

Multidrug-resistant organisms are an established and growing worldwide public health problem and few therapeutic options remain available. The traditional antimicrobials (glycopeptides) for multidrug-resistant Gram-positive infections are declining in efficacy. New drugs that are presently available are linezolid, daptomicin and tigecycline, which have well-defined indications for severe infections, and talavancin, which is under Phase III trial for hospital-acquired pneumonia. Unfortunately the therapies available for multidrug-resistant Gram-negatives, including carbapenem-resistant Pseudomonas aeruginosa, Acinetobacter baumannii and Enterobacteriaceae, are limited to only colistin and tigecycline. Both of these drugs are still not registered for severe infections, such as hospital acquired pneumonia. Consequently, as confirmed by scientific evidence, a multidisciplinary approach is needed. Surveillance, infection control procedures, isolation and antimicrobial stewardship should be implemented to reduce multidrug-resistant organism diffusion.

Contamination rates between smart cell phones and non-smart cell phones of healthcare workers

BACKGROUND

Healthcare workers' mobile phones are easily contaminated with pathogenic bacteria and could be vehicles of transmission. Smart phones are increasingly used in the hospital. The objective of this study was to compare the contamination rate of bacteria with pathogenic potential between smart phones and non-smart phones.

METHODS

We screened mobile phones of healthcare workers in three teaching hospitals in South Korea. The identification of cultivated micro-organisms and assessment of antibiotic susceptibility were performed.

RESULTS

One hundred fifteen (56.7%) participants used smart phones, and 88 (43.3%) used non-smart phones. Bacteria with pathogenic potential were isolated from 58 (28.6%) mobile phones, more often from smart phones than from non-smart phones (34.8% vs 20.5%, P=0.03). Multivariate analysis including various characteristics to determine risk factors revealed that only smart phones (vs non-smart phones) were a significant risk factor for contamination by bacteria with pathogenic potential (adjusted odds ratio [OR], 4.02; 95% confidence interval [CI], 1.43-11.31). Also, in a multivariate model including phone size, the smart phone was still a significant risk factor for the pathogen contamination (OR, 4.17; 95% CI, 1.07-16.33; P=0.04).

CONCLUSION

The smart phones of healthcare workers were contaminated with bacteria with pathogenic potential to a greater extent than were non-smart phones.

Comparison of PCR/electron spray ionization-time-of-flight-mass spectrometry versus traditional clinical microbiology for active surveillance of organisms contaminating high-use surfaces in a burn intensive care unit, an orthopedic ward and healthcare workers

Background

Understanding nosocomial pathogen transmission is restricted by culture limitations. Novel platforms, such as PCR-based electron spray ionization-time-of-flight-mass spectrometry (ESI-TOF-MS), may be useful as investigational tools.

Methods

Traditional clinical microbiology (TCM) and PCR/ESI-TOF-MS were used to recover and detect microorganisms from the hands and personal protective equipment of 10 burn intensive care unit (ICU) healthcare workers providing clinical care at a tertiary care military referral hospital. High-use environmental surfaces were assessed in 9 burn ICU and 10 orthopedic patient rooms. Clinical cultures during the study period were reviewed for pathogen comparison with investigational molecular diagnostic methods.

Results

From 158 samples, 142 organisms were identified by TCM and 718 by PCR/ESI-TOF-MS. The molecular diagnostic method detected more organisms (4.5 ± 2.1 vs. 0.9 ± 0.8, p < 0.01) from 99% vs. 67% of samples (p < 0.01). TCM detected S. aureus in 13 samples vs. 21 by PCR/ESI-TOF-MS. Gram-negative organisms were less commonly identified than gram-positive by both methods; especially by TCM. Among all detected bacterial species, similar percentages were typical nosocomial pathogens (18-19%) for TCM vs. PCR/ESI-TOF-MS. PCR/ESI-TOF-MS also detected mecA in 112 samples, vanA in 13, and KPC-3 in 2. MecA was associated (p < 0.01) with codetection of coagulase negative staphylococci but not S. aureus. No vanA was codetected with enterococci; one KPC-3 was detected without Klebsiella spp.

Conclusions

In this pilot study, PCR/ESI-TOF-MS detected more organisms, especially gram-negatives, compared to TCM, but the current assay format is limited by the number of antibiotic resistance determinants it covers. Further large-scale assessments of PCR/ESI-TOF-MS for hospital surveillance are warranted.

Health outcomes of older patients colonized by multi-drug resistant bacteria (MDRB): a one-year follow-up study

The objective of this study was to examine whether asymptomatic colonization with MDRB would affect outcomes in older patients one year after hospitalization in a geriatric ward. Patient samples were analyzed to identify specific MDRBs, including methicillin-resistant Staphylococcus aureus (MRSA), extended-spectrum beta-lactamase-producing Enterobaceriaceae (ESBLE), and vancomycin-resistant enterococci (VRE). Among 337 patients screened at hospital admission, 62 (18%) carried one or more MDRB isolates (MRSA: n=23; ESBLE: n=39; VRE: n=2). At 12 months after admission, 320 patients were interviewed by telephone (17 patients lost to follow up) to assess all-cause mortality, nursing home admissions, functional decline, and hospital readmissions. All-cause mortality rates were similar in MDRB carriers (34%; n=61) and non-carriers (30%; n=259) (P=0.512). Nursing home admission, functional decline, and hospital readmission did not differ between the two groups. In this population, predictors of mortality were: male gender (P=0.002), cognitive disorders at admission (P=0.028), low pre-albumin level at admission (P=0.048), a high level of co-morbidities (P=0.002), and a history of an acute condition in the three months prior to initial hospital admission (P=0.024). In conclusion, in this cohort of older patients, asymptomatic MDRB colonization was not significantly associated with adverse health outcomes at a one-year follow-up after hospitalization. The potential limitations of the study were the small sample size, relatively high mortality rate, and lack of MDRB reassessment during the follow-up.

Multidrug-resistant bacteria colonization amongst patients newly admitted to a geriatric unit: a prospective cohort study

OBJECTIVES

To determine prevalence, incidence and risk factors of colonization by extended-spectrum β-lactamase-producing Enterobacteriacae (ESBLE), methicillin-resistant Staphylococcus aureus (MRSA), and vancomycin-resistant Enterococcus (VRE) in aged subjects admitted to an acute geriatric unit at a teaching hospital.

METHODS

During 12 months, 337 patients were screened by nasal, oropharyngeal, groin, axillary and rectal swabs upon admission and at discharge.

RESULTS

The prevalence of ESBLE, MRSA and VRE carriage upon admission was 11.6%, 7.5% and 0.6%, respectively. The incidence density of ESBLE and MRSA carriage was respectively of 1.77 and 2.40 new cases for 1000 patient-days. No cases of VRE acquisition were found. Risk factors for ESBLE colonization on admission were: multiple contacts with the hospital within the previous year, chronic catheter use and a high level of dependency. For MRSA, risk factors were: chronic wounds, anti-acid use and a high level of dependency.

CONCLUSION

This study shows a high prevalence of asymptomatic colonization of ESBL-producing Escherichia coli in patients admitted to an acute geriatric ward, as high as MRSA carriage. A low functional status is a common risk factor both for ESBLE and for MRSA colonization and it highlights the need to reinforce infection control measures.

The challenges of antimicrobial drug resistance in Greece

Antimicrobial drug resistance rates in Greece are among the highest in Europe. The prevalence of carbapenem-resistant Gram-negative species has increased considerably, including endemic strains in intensive care units. Pandrug-resistant Klebsiella pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa are sporadically reported. Methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus rates are also high in Greek hospitals. Multidrug resistance increases risk of mortality, hospitalization duration and costs, and undermines the medical system. Administrative responses initiated include action plans, monitoring systems, and guidelines. Common terminology among involved parties for defining and grading resistance is required. Multidrug-resistant microorganisms challenge clinical laboratories; uniform recommendations towards detection of resistance mechanisms need to be established. Prospective multicenter outcome studies comparing antibiotic regimens and containment methods are needed. Because new antimicrobials against Gram-negative pathogens are not foreseeable, judicious use of the existing and strict adherence to infection control best practice might restrain resistance spread. Awareness of resistance patterns and organisms prevailing locally by reporting laboratories and treating physicians is important.

Evaluation of the DiversiLab typing method in a multicenter study assessing horizontal spread of highly resistant gram-negative rods

The worldwide prevalence of highly resistant Gram-negative rods (HR-GNR) is increasing rapidly. Reliable typing methods are needed to detect and control outbreaks and to monitor the effectiveness of infection control programs in endemic situations. In this study, we investigated the performance of the DiversiLab typing method in comparison with the amplified fragment length polymorphism (AFLP) typing method. Six hundred fifty-three HR-GNR isolates, which were obtained during a 6-month prospective survey in 18 Dutch hospitals, were typed by AFLP and DiversiLab. Subsequently, the sensitivity and specificity of DiversiLab were calculated, using AFLP as the reference method. In addition, results were compared by means of epidemiological linkage, and Cohen's kappa for agreement was calculated. DiversiLab considered significantly more isolates (275) to belong to a cluster than AFLP (198) (P < 0.001). In direct comparison, the sensitivity was 83.8%, and the specificity was 78.6%. When epidemiological linkage was included in the analysis, DiversiLab considered eight isolates as secondary cases, which were considered unique in AFLP. Only two secondary cases, according to AFLP, were missed by DiversiLab. This results in a kappa for agreement of 0.985. In daily practice, a typing method has to be used in combination with epidemiological information. When this was done, DiversiLab was shown to be a reliable method for the typing of HR-GNR. This, in combination with the ease of use and the speed, makes DiversiLab an appropriate method for screening in routine clinical practice. When a cluster is suspected and the consequences of these findings are substantial, a confirmatory analysis should be performed.

Highly resistant gram-negative microorganisms: incidence density and occurrence of nosocomial transmission (TRIANGLe Study)

OBJECTIVES

The objectives of this study were to determine the incidence density and the occurrence of horizontal spread of highly resistant gram-negative rods (HR-GNRs) in Dutch hospitals. The factors that influence these outcome measures were also investigated.

METHODS

All patients with HR-GNRs, as determined by sample testing, who were hospitalized in 1 of 18 hospitals during a 6-month period (April through October 2007) were included in this study. For all available isolates, the species was identified, susceptibility was determined (including the presence of extended-spectrum β-lactamases [ESBLs]), and molecular typing was performed. On the basis of a combination of species identification, molecular typing, and epidemiological data, the occurrence of nosocomial transmission was determined.

RESULTS

The mean incidence density of patients with HR-GNRs was 55 per 100,000 patient-days (cumulative incidence, 39 per 10,000 patients admitted). A facility being a university hospital was a statistically significant (P = .03) independent determinant of a higher incidence of patients with HR-GNRs. The majority of HR-GNR isolates were ESBL producers. The adjusted transmission index-the ratio between secondary and primary cases-in the participating hospitals ranged from 0.0 to 0.2. The overall adjusted transmission index of HR-GNRs was 0.07. No determinants for a higher transmission index were identified.

DISCUSSION

The nosocomial transmission rate of HR-GNRs was relatively low in all hospitals where well-established transmission-based precautions were used. The incidence density of patients with HR-GNRs was higher in university hospitals, probably due to the patient population and the complexity of the care provided.

Hospital epidemiology and infection control in acute-care settings

Health care-associated infections (HAIs) have become more common as medical care has grown more complex and patients have become more complicated. HAIs are associated with significant morbidity, mortality, and cost. Growing rates of HAIs alongside evidence suggesting that active surveillance and infection control practices can prevent HAIs led to the development of hospital epidemiology and infection control programs. The role for infection control programs has grown and continues to grow as rates of antimicrobial resistance rise and HAIs lead to increasing risks to patients and expanding health care costs. In this review, we summarize the history of the development of hospital epidemiology and infection control, common HAIs and the pathogens causing them, and the structure and role of a hospital epidemiology and infection control program.

Infection Control and the Long-Term Care Facility

Approximately 70% of health care associated pathogens are resistant to one or more antibiotics. Experts maintain that most antimicrobial-resistant pathogens develop from antibiotic overuse and inappropriate antibiotic selection or treatment duration. Up to 70% of long-term care residents receive at least one course of an antimicrobial agent during a one-year period. Four types of infections occur most often among long-term care residents: urinary tract, respiratory tract, skin and soft tissue, and gastrointestinal tract, and outbreaks are common. Diagnostic uncertainty, failure to recognize fever's clinical manifestation in the elderly, treatment of asymptomatic bacteriuria, and bacterial colonization contribute to antibiotic overuse. Recent infection control guidelines recommend more targeted antibiotic utilization review. Recommendations are presented for implementing antibiotic utilization programs. Hand washing and other measures, such as droplet precautions, are discussed. Economic disincentives surrounding antimicrobial research are highlighted.

Acquisition of vancomycin-resistant enterococci in internal medicine wards

BACKGROUND

Our institution experienced an increase in the frequency of vancomycin-resistant enterococci (VRE) clinical isolates, which rose 5-fold from 2004 to 2005. We sought to measure the prevalence of VRE carriage among medical inpatients in a tertiary hospital in Jerusalem and estimate the rate of acquisition during hospitalization.

METHODS

During 2006, we performed 3 cross-sectional surveys, including 1039 patients, representing 3 phases of hospitalization: admission, hospital stay, and discharge. Perianal/stool samples were cultured for VRE.

RESULTS

VRE carriage was 3.8% (95% confidence interval [CI] = 1.8% to 6.9%) on admission, 15% (95% CI = 9% to 23%) at discharge, and 32% (95% CI = 24% to 40%) among inpatients. Among inpatient carriers, 60% of the isolates represented a single strain. Recent previous hospitalization was the most significant predictor for identifying carriers on admission.

CONCLUSIONS

Our study demonstrates that substantial VRE transmission occurred during hospitalization. Identification of carriers on admission should supplement effective application of infection control methods in attempting to decrease VRE nosocomial spread and burden.

Highly resistant microorganisms in a teaching hospital: the role of horizontal spread in a setting of endemicity

OBJECTIVE

To determine the incidence density of highly resistant organisms (HROs) and the relative contribution of horizontal spread in a setting of endemicity.

METHODS

Prospective surveillance was performed among hospitalized patients during an 18-month period. Enterobacteriaceae, nonfermentative gram-negative bacilli, Staphylococcus aureus, Streptococcus pneumoniae, and Enterococcus faecium--all considered highly resistant, according to Dutch guidelines--were included. Epidemiological linkage and nosocomial transmission were determined on the basis of molecular typing and hospital admission data.

RESULTS

From 119 patients, we recovered a total of 170 unique HRO isolates, as follows: Escherichia coli, 96 isolates; Klebsiella species, 11 isolates; Enterobacter species, 8 isolates; Proteus species, 9 isolates; Citrobacter species, 5 isolates; Pseudomonas species, 5 isolates; Acinetobacter species, 3 isolates; Morganella species, 2 isolates; Salmonella species, 1 isolate; Serratia species, 1 isolate; S. pneumoniae, 20 isolates; and S. aureus, 9 isolates. No vancomycin-resistant E. faecium was found. The incidence density was 4.3 HRO isolates per 10,000 patient-days. The majority of HRO isolates were unique, and nosocomial transmission was observed 4 times for highly resistant gram-negative bacilli (case reproduction rate, 0.05) and 4 times for penicillin-nonsusceptible S. pneumoniae (case reproduction rate, 0.29). A stay on the intensive care unit was the main determinant for the recovery of an HRO.

CONCLUSION

Nosocomial transmission of HROs was observed 8 times during the 18-month period. The intensive care unit was identified as the main reservoir of horizontal spread of HROs. This study shows that nosocomial transmission of HROs is largely preventable using transmission precautions.

Methicillin-resistant Staphylococcus aureus (MRSA) among dental patients: a problem for infection control in dentistry?

We assessed the frequency of carriers of methicillin-resistant Staphylococcus aureus (MRSA) among 500 dental patients of a university clinic. From each participant, two specimens were taken from the anterior nares and the pharynx and analysed by culture. The participants completed a questionnaire on possible risk factors of MRSA infection. Two hundred ten individuals carried S. aureus, 90 in the nares only, 51 in the throat only and 69 in nares and throat. Isolates of 208 patients were methicillin-sensitive; two isolates were methicillin-resistant, both carried in the throat exclusively. In conclusion, the frequency of nasal and/or throat carriers of MRSA among dental patients was low and suggests few opportunities of exposure in the dental clinic assessed.

The role of healthcare personnel in the maintenance and spread of methicillin-resistant Staphylococcus aureus

Healthcare workers may acquire methicillin-resistant Staphylococcus aureus (MRSA) from patients, both hospital and home environments, other healthcare workers, family and public acquaintances, and pets. There is a consensus of case reports and series which now strongly support the role for MRSA-carrying healthcare personnel to serve as a reservoir and as a vehicle of spread within healthcare settings. Carriage may occur at a number of body sites and for short, intermediate, and long terms. A number of approaches have been taken to interrupt the linkage of staff-patient spread, but most emphasis has been placed on handwashing and the treatment of staff MRSA carriers. The importance of healthcare workers in transmission has been viewed with varying degrees of interest, and several logistical problems have arisen when healthcare worker screening is brought to the forefront. There is now considerable support for the screening and treatment of healthcare workers, but it is suggested that the intensity of any such approach must consider available resources, the nature of the outbreak, and the strength of epidemiological associations. The task of assessing healthcare personnel carriage in any context should be shaped with due regard to national and international guidelines, should be honed and practiced according to local needs and experience, and must be patient-oriented.

Who is steering the ship? External influences on infection control programs

Over the past decade, hospital infection control programs have begun to face new external influences that affect day-to-day practice. The mainstream media's interest in hospital-acquired infection sparked consumer interest, which resulted in more legislative activity and government regulation. Industry's influence is also increasing. To meet the increased demands of external agencies, infection control programs will need additional resources, and the infection control community will need to be more proactive in educating the public and defining the priorities for practice and research.

Health-care workers: source, vector, or victim of MRSA?

There is ongoing controversy about the role of health-care workers in transmission of meticillin-resistant Staphylococcus aureus (MRSA). We did a search of the literature from January, 1980, to March, 2006, to determine the likelihood of MRSA colonisation and infection in health-care workers and to assess their role in MRSA transmission. In 127 investigations, the average MRSA carriage rate among 33 318 screened health-care workers was 4.6%; 5.1% had clinical infections. Risk factors included chronic skin diseases, poor hygiene practices, and having worked in countries with endemic MRSA. Both transiently and persistently colonised health-care workers were responsible for several MRSA clusters. Transmission from personnel to patients was likely in 63 (93%) of 68 studies that undertook genotyping. MRSA eradication was achieved in 449 (88%) of 510 health-care workers. Subclinical infections and colonisation of extranasal sites were associated with persistent carriage. We discuss advantages and disadvantages of screening and eradication policies for MRSA control and give recommendations for the management of colonised health-care workers in different settings.

Indwelling device use and antibiotic resistance in nursing homes: identifying a high-risk group

OBJECTIVES

To quantify the relationship between indwelling devices (urinary catheters, feeding tubes, and peripherally inserted central catheters) and carriage of antimicrobial-resistant pathogens in nursing home residents.

DESIGN

Cross-sectional.

SETTING

Community nursing home in Southeast Michigan.

PARTICIPANTS

Residents with indwelling devices (n=100) and randomly selected control residents (n=100) in 14 nursing homes.

MEASUREMENTS

Data on age, functional status, and Charlson comorbidity score were collected. Samples were obtained from nares, oropharynx, groin, wounds, perianal area, and enteral feeding tube site. Standard microbiological methods were used to identify methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), and ceftazidime-resistant (CTZ-R) gram-negative bacteria (GNB).

RESULTS

Use of indwelling devices was associated with colonization with MRSA at any site (odds ratio (OR)=2.0, P=.04), groin (OR=4.8, P=.006), and perianal area (OR=3.6, P=.01) and CTZ-R GNB at any site (OR=5.6, P=.003). Use of enteral feeding tubes was associated with MRSA colonization in the oropharynx (OR=3.3, P=.02).

CONCLUSION

Use of indwelling devices is associated with greater colonization with antimicrobial-resistant pathogens. This study serves as an initial step in defining a high-risk group that merits intensive infection control efforts.

Interventions to prevent transmission of antimicrobial-resistant bacteria in the intensive care unit

PURPOSE OF REVIEW

Healthcare-associated infections caused by methicillin-resistant Staphylococcus aureus (MRSA), vancomycin resistant Enterococcus (VRE), and multidrug resistant Gram negative bacilli are a serious problem in ICUs. This review analyzes recent reports of interventions to prevent transmission of these organisms in the ICU.

RECENT FINDINGS

Two multicenter retrospective cohort studies demonstrated that surveillance cultures are necessary to identify the full reservoir of patients colonized with MRSA or VRE. A single center, interrupted time series study found that the incidence of healthcare-associated MRSA bacteremia was reduced after initiation of MRSA surveillance cultures. Other studies with various designs describe the effect of active surveillance on the use of isolation precautions, sustained improvements in compliance with hand hygiene and glove use associated with a multimodal intervention, reduced transmission of VRE associated with chlorhexidine bathing and improved environmental cleaning, and the efficacy of a MRSA decolonization regimen.

SUMMARY

Progress is being made in identifying interventions to prevent transmission of antimicrobial resistant bacteria in ICUs, although the strength of the evidence is limited compared with many therapeutic interventions. Large MRSA control initiatives launched during 2006 and 2007 may build on this work; their effects should be evaluated using proper study designs and analyses.

Antimicrobial resistance in critical care

Patients presenting with active infections or at increased risk for infections pose a significant challenge in critical care nursing. It is important for critical care nurses to use effective antimicrobial strategies in patient management to reduce the potential development of antimicrobial resistance. They should be involved actively in promoting patient management through development of research-based nursing guidelines and protocols.

Look before You Leap: Active Surveillance for Multidrug-Resistant Organisms

Hospitals in the United States are under increasing pressure to perform active surveillance cultures for detection of methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE) among newly admitted patients. Results of such cultures can then be used to direct contact precautions to prevent transmission of MRSA and VRE in the health care setting. However, using active surveillance cultures to expand contact precautions is a complicated and resource-intensive intervention that has the potential for several unintended adverse consequences. Therefore, careful forethought and preparation should precede the institution of any active surveillance culture program. We review the following important steps that should be performed when planning any such intervention: preparing the laboratory and reducing the turnaround time for screening tests, monitoring and optimizing the intervention of instituting contact precautions, monitoring and ameliorating the known adverse effects of contact precautions, and measuring important outcomes to evaluate the effectiveness of a program of active surveillance cultures and contact precautions.