Use of adherence monitors as part of a team approach to control clonal spread of multidrug-resistant Acinetobacter baumannii in a research hospital

A systematic review of the effectiveness of cohorting to reduce transmission of healthcare-associated C. difficile and multidrug-resistant organisms

BACKGROUND

Cohorting of patients and staff is a control strategy often used to prevent the spread of infection in healthcare institutions. However, a comprehensive evaluation of cohorting as a prevention approach is lacking.

METHODS

We performed a systematic review of studies that used cohorting as part of an infection control strategy to reduce hospital-acquired infections. We included studies published between 1966 and November 30, 2019, on adult populations hospitalized in acute-care hospitals.

RESULTS

In total, 87 studies met inclusion criteria. Study types were quasi-experimental "before and after" (n = 35), retrospective (n = 49), and prospective (n = 3). Case-control analysis was performed in 7 studies. Cohorting was performed with other infection control strategies in the setting of methicillin-resistant Staphylococcus aureus (MRSA, n = 22), Clostridioides difficile infection (CDI, n = 6), vancomycin-resistant Enterococcus (VRE, n = 17), carbapenem-resistant Enterobacteriaceae infections (CRE, n = 22), A. baumannii (n = 15), and other gram-negative infections (n = 5). Cohorting was performed either simultaneously (56 of 87, 64.4%) or in phases (31 of 87, 35.6%) to help contain transmission. In 60 studies, both patients and staff were cohorted. Most studies (77 of 87, 88.5%) showed a decline in infection or colonization rates after a multifaceted approach that included cohorting as part of the intervention bundle. Hand hygiene compliance improved in approximately half of the studies (8 of 15) during the respective intervention.

CONCLUSION

Cohorting of staff, patients, or both is a frequently used and reasonable component of an enhanced infection control strategy. However, determining the effectiveness of cohorting as a strategy to reduce transmission of MDRO and C. difficile infections is difficult, particularly in endemic situations.

Preventing Transmission of Multidrug-Resistant Pathogens in the Intensive Care Unit

Infection control in the intensive care unit (ICU) has seen many advances, including rapid molecular screening tests for resistant organisms and chlorhexidine use in daily baths. Although these developments advance the cause of infection prevention, compliance with some of the basic measures remains elusive. Hand hygiene, antimicrobial stewardship, and reduction in device use remain the low-technology interventions that could have a major impact on nosocomial transmission of antimicrobial-resistant organisms. Although continued research is needed on new and old ways of preventing nosocomial infections, ICU staff must persevere in improving adherence with the measures that are known to be effective.

Clinical and economic impact of meropenem resistance in Pseudomonas aeruginosa-infected patients

BACKGROUND

The emergence of carbapenem resistance has had a significant impact on both clinical and economic outcomes.

METHODS

A retrospective, observational cohort study was performed in a 433-bed tertiary care medical center. The cohort was established from all inpatients with Pseudomonas aeruginosa-positive cultures over a 3-year period. Two multivariate models were developed: a logistic regression model to evaluate the primary outcome of in-hospital mortality and a linear regression model to evaluate the secondary outcome of total hospital cost.

RESULTS

The adjusted odds ratio for in-hospital mortality among patients with meropenem-resistant isolates was 2.89 (95% confidence interval [CI], 1.15-7.28). There were significantly more deaths in the meropenem-resistant group (28.1% vs 8.9%, P = .003). Patients with meropenem-resistant P aeruginosa experienced a 4-day increase in median length of stay versus those in the meropenem-susceptible group (14 vs 9 days, P = .004). Likewise, the percentage of patients who required intensive care unit (ICU) admission increased from 42% to 81.3% (P <.001). Meropenem resistance was also associated with a significant increase in total hospital cost by a factor of 1.42 among patients who were not admitted to the ICU (95% CI, 1.03-1.95).

CONCLUSIONS

Our results demonstrate that meropenem resistance was a significant predictor of in-hospital mortality. Carbapenem resistance also resulted in a significant increase in hospital cost, but only among patients who were not admitted to the ICU.

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.

Control of a two-decade endemic situation with carbapenem-resistant Acinetobacter baumannii: electronic dissemination of a bundle of interventions

BACKGROUND

Our institution continued to experience a hyperendemic situation with carbapenem-resistant Acinetobacter baumannii despite a bundle of interventions. We aim to describe the effect of the subsequent implementation of electronic dissemination of the weekly findings of a bundle of interventions.

METHODS

This was a quasiexperimental study performed at a 1,500-bed, public, teaching hospital. From January 2011 to March 2012, weekly electronic communications were sent to the hospital leadership and intensive care units (ICUs). These communications aimed to describe, interpret, and package the findings of the previous week's active surveillance cultures, environmental cultures, environmental disinfection, and hand cultures. Additionally, action plans based on these findings were shared with recipients.

RESULTS

During 42 months and 1,103,900 patient-days, we detected 438 new acquisitions of carbapenem-resistant A baumannii. Hospital wide, the rate of acquisition decreased from 5.13 ± 0.39 to 1.93 ± 0.23 per 10,000 patient-days, during the baseline and postintervention periods, respectively (P < .0001). This effect was also observed in the medical and trauma ICUs, with decreased rates from 67.15 ± 10.56 to 17.4 ± 4.6 (P < .0001) and from 55.9 ± 8.95 to 14.71 ± 4.45 (P = .0004), respectively.

CONCLUSION

Weekly and systematic dissemination of the findings of a bundle of interventions was successful in decreasing the rates of carbapenem-resistant A baumannii across a large public hospital.

Successful implementation of a unit-based quality nurse to reduce central line-associated bloodstream infections

BACKGROUND

Central line (CL)-associated bloodstream infections (CLABSI) are an important cause of patient morbidity and mortality. Novel strategies to prevent CLABSI are needed.

METHODS

We described a quasiexperimental study to examine the effect of the presence of a unit-based quality nurse (UQN) dedicated to perform patient safety and infection control activities with a focus on CLABSI prevention in a surgical intensive care unit (SICU).

RESULTS

From July 2008 to March 2012, there were 3,257 SICU admissions; CL utilization ratio was 0.74 (18,193 CL-days/24,576 patient-days). The UQN program began in July 2010; the nurse was present for 30% (193/518) of the days of the intervention period of July 2010 to March 2012. The average CLABSI rate was 5.0 per 1,000 CL-days before the intervention and 1.5 after the intervention and decreased by 5.1% (P = .005) for each additional 1% of days of the month that the UQN was present, even after adjusting for CLABSI rates in other adult intensive care units, time, severity of illness, and Comprehensive Unit-based Safety Program participation (5.1%, P = .004). Approximately 11.4 CLABSIs were prevented.

CONCLUSION

The presence of a UQN dedicated to perform infection control activities may be an effective strategy for CLABSI reduction.

Managing transmission of carbapenem-resistant enterobacteriaceae in healthcare settings: a view from the trenches

In 2011, the National Institutes of Health Clinical Center experienced a cluster of infection and colonization caused by carbapenem-resistant Klebsiella pneumoniae among profoundly immunocompromised inpatients. This manuscript describes the approach and interventions that were implemented in an attempt to curtail the cluster. Interventions employed included engagement of all stakeholders involved in care of at-risk patients; detailed and frequent communication with hospital staff about issues relating to the outbreak; aggressive microbial surveillance; use of techniques that facilitate rapid identification of resistant organisms; rapid characterization of resistance mechanisms; whole-genome sequencing of outbreak isolates to characterize the spread and to investigate mechanisms of healthcare-associated spread; implementation of enhanced contact precautions for all infected or colonized patients; geographic and personnel cohorting; daily chlorhexidine gluconate baths; dedicating equipment to be used solely for cohorted patients and aggressive decontamination of equipment that had to be reused on uncohorted patients; monitoring adherence to infection control precautions, including unwavering attention to adherence to appropriate hand hygiene procedures; and attention to the details of environmental decontamination. In addition, the manuscript discusses some of the challenges associated with managing such an event, as well as a few of the unanticipated consequences associated with the aftermath of the case cluster.

Tracking a hospital outbreak of carbapenem-resistant Klebsiella pneumoniae with whole-genome sequencing

The Gram-negative bacteria Klebsiella pneumoniae is a major cause of nosocomial infections, primarily among immunocompromised patients. The emergence of strains resistant to carbapenems has left few treatment options, making infection containment critical. In 2011, the U.S. National Institutes of Health Clinical Center experienced an outbreak of carbapenem-resistant K. pneumoniae that affected 18 patients, 11 of whom died. Whole-genome sequencing was performed on K. pneumoniae isolates to gain insight into why the outbreak progressed despite early implementation of infection control procedures. Integrated genomic and epidemiological analysis traced the outbreak to three independent transmissions from a single patient who was discharged 3 weeks before the next case became clinically apparent. Additional genomic comparisons provided evidence for unexpected transmission routes, with subsequent mining of epidemiological data pointing to possible explanations for these transmissions. Our analysis demonstrates that integration of genomic and epidemiological data can yield actionable insights and facilitate the control of nosocomial transmission.

Genomic insights into the fate of colistin resistance and Acinetobacter baumannii during patient treatment

Bacterial whole-genome sequencing (WGS) of human pathogens has provided unprecedented insights into the evolution of antibiotic resistance. Most studies have focused on identification of resistance mutations, leaving one to speculate on the fate of these mutants once the antibiotic selective pressure is removed. We performed WGS on longitudinal isolates of Acinetobacter baumannii from patients undergoing colistin treatment, and upon subsequent drug withdrawal. In each of the four patients, colistin resistance evolved via mutations at the pmr locus. Upon colistin withdrawal, an ancestral susceptible strain outcompeted resistant isolates in three of the four cases. In the final case, resistance was also lost, but by a compensatory inactivating mutation in the transcriptional regulator of the pmr locus. Notably, this inactivating mutation reduced the probability of reacquiring colistin resistance when subsequently challenged in vitro. On face value, these results supported an in vivo fitness cost preventing the evolution of stable colistin resistance. However, more careful analysis of WGS data identified genomic evidence for stable colistin resistance undetected by clinical microbiological assays. Transcriptional studies validated this genomic hypothesis, showing increased pmr expression of the initial isolate. Moreover, altering the environmental growth conditions of the clinical assay recapitulated the classification as colistin resistant. Additional targeted sequencing revealed that this isolate evolved undetected in a patient undergoing colistin treatment, and was then transmitted to other hospitalized patients, further demonstrating its stability in the absence of colistin. This study provides a unique window into mutational pathways taken in response to antibiotic pressure in vivo, and demonstrates the potential for genome sequence data to predict resistance phenotypes.

Pan-PCR, a computational method for designing bacterium-typing assays based on whole-genome sequence data

With increasing rates of antibiotic resistance, bacterial infections have become more difficult to treat, elevating the importance of surveillance and prevention. Effective surveillance relies on the availability of rapid, cost-effective, and informative typing methods to monitor bacterial isolates. PCR-based typing assays are fast and inexpensive, but their utility is limited by the lack of targets which are capable of distinguishing between strains within a species. To identify highly informative PCR targets from the growing base of publicly available bacterial genome sequences, we developed pan-PCR. This computer algorithm uses existing genome sequences for isolates of a species of interest and identifies a set of genes whose patterns of presence or absence provide the best discrimination between strains in this species. A set of PCR primers targeting the identified genes is then designed, with each PCR product being of a different size to allow multiplexing. These target DNA regions and PCR primers can then be utilized to type bacterial isolates. To evaluate pan-PCR, we designed an assay for the emerging pathogen Acinetobacter baumannii. Taking as input a set of 29 previously sequenced genomes, pan-PCR identified 6 genetic loci whose presence or absence was capable of distinguishing all the input strains. This assay was applied to a set of patient isolates, and its discriminatory power was compared to that of multilocus sequence typing (MLST) and whole-genome optical maps. We found that the pan-PCR assay was capable of making clinically relevant distinctions between strains with identical MLST profiles and showed a discriminatory power similar to that of optical maps. Pan-PCR represents a tool capable of exploiting available genome sequence data to design highly discriminatory PCR assays. The ease of design and implementation makes this approach feasible for diagnostic facilities of all sizes.

Assessing the burden of Acinetobacter baumannii in Maryland: a statewide cross-sectional period prevalence survey

OBJECTIVE

To determine the prevalence of Acinetobacter 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 with A. baumannii, were included.

RESULTS

Seventy percent (40/57) of all eligible healthcare facilities participated in the survey, representing both acute care ([Formula: see text]) and LTC ([Formula: see text]) facilities in all geographic regions of Maryland. Surveillance cultures were obtained from 92% (358/390) of eligible patients. A. baumannii was identified in 34% of all mechanically ventilated patients in Maryland; multidrug-resistant A. baumannii was found in 27% of all patients. A. baumannii was 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. baumannii was identified from all facilities in which 10 or more patients were sampled.

CONCLUSIONS

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