Impact of intensive care unit relocation and role of tap water on an outbreak of Pseudomonas aeruginosa expressing OprD-mediated resistance to imipenem

Sinks in patient rooms in ICUs are associated with higher rates of hospital-acquired infection: a retrospective analysis of 552 ICUs

BACKGROUND

Sinks in hospitals are a possible reservoir for healthcare-related pathogens. They have been identified as a source of nosocomial outbreaks in intensive care units (ICU); however, their role in non-outbreak settings remains unclear.

AIM

To investigate whether sinks in ICU patient rooms are associated with a higher incidence of hospital-acquired infection (HAI).

METHODS

This analysis used surveillance data from the ICU component of the German nosocomial infection surveillance system (KISS) from 2017 to 2020. Between September and October 2021, all participating ICUs were surveyed about the presence of sinks in their patient rooms. The ICUs were then divided into two groups: the no-sink group (NSG) and the sink group (SG). Primary and secondary outcomes were total HAIs and HAIs associated with Pseudomonas aeruginosa (HAI-PA).

FINDINGS

In total, 552 ICUs (NSG N=80, SG N=472) provided data about sinks, total HAIs and HAI-PA. The incidence density per 1000 patient-days of total HAIs was higher in ICUs in the SG (3.97 vs 3.2). The incidence density of HAI-PA was also higher in the SG (0.43 vs 0.34). The risk of HAIs associated with all pathogens [incidence rate ratio (IRR)=1.24, 95% confidence interval (CI) 1.03-1.50] and the risk of lower respiratory tract infections associated with P. aeruginosa (IRR=1.44, 95% CI 1.10-1.90) were higher in ICUs with sinks in patient rooms. After adjusting for confounders, sinks were found to be an independent risk factor for HAI (adjusted IRR 1.21, 95% CI 1.01-1.45).

CONCLUSIONS

Sinks in patient rooms are associated with a higher number of HAIs per patient-day in the ICU. This should be considered when planning new ICUs or renovating existing ones.

Mechanisms of Antibiotic and Biocide Resistance That Contribute to Pseudomonas aeruginosa Persistence in the Hospital Environment

Pseudomonas aeruginosa is an opportunistic bacterial pathogen responsible for multiple hospital- and community-acquired infections, both in human and veterinary medicine. P. aeruginosa persistence in clinical settings is worrisome and is a result of its remarkable flexibility and adaptability. This species exhibits several characteristics that allow it to thrive under different environmental conditions, including the ability to colonize inert materials such as medical equipment and hospital surfaces. P. aeruginosa presents several intrinsic mechanisms of defense that allow it to survive external aggressions, but it is also able to develop strategies and evolve into multiple phenotypes to persevere, which include antimicrobial-tolerant strains, persister cells, and biofilms. Currently, these emergent pathogenic strains are a worldwide problem and a major concern. Biocides are frequently used as a complementary/combination strategy to control the dissemination of P. aeruginosa-resistant strains; however, tolerance to commonly used biocides has also already been reported, representing an impediment to the effective elimination of this important pathogen from clinical settings. This review focuses on the characteristics of P. aeruginosa responsible for its persistence in hospital environments, including those associated with its antibiotic and biocide resistance ability.

Outbreak investigations after identifying carbapenem-resistant Pseudomonas aeruginosa: a systematic review

BACKGROUND

Carbapenem-resistant Pseudomonas aeruginosa (CRPA) are a serious cause of healthcare-associated infections. Part of the infection prevention and control measures are outbreak investigations (OI) of patients, healthcare workers (HCW), and the environment after identifying a CRPA in order to identify carriers and environmental reservoirs, so that targeted actions can be taken to prevent further transmission. However, little is known on when and how to perform such OI. Therefore, this systematic review aims to summarize OI performed after detection of CRPA in the endemic and epidemic hospital setting.

MAIN TEXT

Articles related to our research question were identified through a literature research in multiple databases (Embase, Medline Ovid, Cochrane, Scopus, Cinahl, Web of Science, and Google Scholar) until January 12, 2022 (Prospero registration number CRD42020194165). Hundred-twenty-six studies were included. In both the endemic and the epidemic setting, a median number of two out of seven predefined components of OI were identified. In the endemic setting, the most frequent component of OI was screening of the environment (28 studies, 62.2%). In the epidemic setting, screening of the environment (72 studies, 88.9%), and screening of patients during hospitalization (30 studies, 37%) were most frequently performed. Only 19 out of 126 studies (15.1%) reported screening of contact patients, and 37 studies reported screening of healthcare workers (HCW, 29.4%).

CONCLUSION

Due to probable underreporting of OI in the literature, the available evidence for the usefulness of the individual components of OI is scarce. This could lead to inhomogeneous performance of OI after detection of CRPA in the healthcare setting, and with this, potential under- or overscreening. While we could show evidence for the usefulness for environmental screening in order to identify the mode of transmission, evidence for HCW screening is scarce and might not lead to the identification of modes of transmission. Further studies are needed to better understand CI in different settings and, finally, develop guidance on when and how to best perform OI.

Plasmid-Borne AFM Alleles in Pseudomonas aeruginosa Clinical Isolates from China

Carbapenem-resistant Pseudomonas aeruginosa (CRPA) is a pathogen of global concern due to the fact that therapeutic drugs are limited. Metallo-β-lactamase (MBL)-producing P. aeruginosa has become a critical part of CRPA. Alcaligenes faecalis metallo-β-lactamase (AFM) is a newly identified subclass B1b MBL. In this study, 487 P. aeruginosa strains isolated from patients and the environment in an intensive care unit were screened for AFM alleles. Five AFM-producing strains were identified, including four AFM-2-producing strains (ST262) and one AFM-4-producing strain (ST671). AFM-2-producing strains were isolated from rectal and throat swabs, and AFM-4-producing strains were isolated from the water sink. The bla_AFM-2 carrying plasmids belonged to the IncP-2 type, while the bla_AFM-4 carrying plasmid pAR19438 was a pSTY-like megaplasmid. Plasmid pAR19438 was acquired bla_AFM-4 by the integration of the Tn1403-like transposon. All bla_AFM genes were embedded in an ISCR29-bla_AFM unit core module flanked by class 1 integrons. The core module of bla_AFM-2 was ISCR29-ΔgroL-bla_AFM-2-ble_MBL-ΔtrpF-ΔISCR, while the core module of bla_AFM-4 was ISCR29-ΔgroL-bla_AFM-2-ble_MBL-ΔtrpF-ISCR-msrB-msrA-yfcG-corA-ΔISCR. The flanking sequences of ISCR29-bla_AFM units also differed. The expression of AFM-2 and AFM-4 in DH5α and PAO1 illustrated the same effect for the evaluation of the MICs of β-lactams, except for aztreonam. Identification of AFM-4 underscores that the quick spread and emerging development of mutants of MBLs require continuous surveillance in P. aeruginosa. IMPORTANCE Acquiring metallo-β-lactamase genes is one of the important carbapenem resistance mechanisms of P. aeruginosa. Alcaligenes faecalis metallo-β-lactamase is a newly identified metallo-β-lactamase, the prevalence and genetic context of which need to be explored. In this study, we identified AFM-producing P. aeruginosa strains among clinical isolates and found a new mutant of AFM, AFM-4. The bla_AFM-4 carrying plasmid pAR19438 was a pSTY-like megaplasmid, unlike the plasmids encoding other bla_AFM alleles. The genetic context of bla_AFM-4 was also different. However, AFM-2 and AFM-4 had the same impacts on antibiotic susceptibility. The presence and transmission of AFM alleles in P. aeruginosa pose a challenge to clinical practice.

Controlling bacteriological contamination of environmental surfaces at the biological isolation and containment unit of a veterinary teaching hospital

Background

The Biological Isolation and Containment Unit (BICU) is a subunit of the Teaching Hospital of the Faculty of Veterinary Medicine of the University of Lisbon, Portugal, for the admission of animals with confirmed infectious diseases or under clinical suspicion and waiting for a diagnosis. As a high-risk environment for the transmission of infectious agents, it is extremely important to implement programs for the surveillance of nosocomial microorganisms in these facilities. The purpose of this study was to evaluate the level of bacterial contamination of the BICU environmental surfaces and to implement corrective actions on disinfection protocols. Swab samples were collected from selected environmental surfaces in 3 different areas of the BICU (isolation, work, and preparatory rooms) to evaluate the total aerobic bacterial load and investigate the presence of 4 nosocomial microorganisms: vancomycin-resistant Enterococcus spp., methicillin-resistant Staphylococcus aureus, 3rd-generation cephalosporin-resistant Escherichia coli, and carbapenem-resistant Pseudomonas aeruginosa. Bacterial quantification was performed by using non-selective media, while specific selective media were used for the isolation of the target microorganisms. Isolates were identified based on their macro and microscopic characteristics and their biochemical profile. Subsequently, new disinfection protocols were implemented, and their effectiveness evaluated.

Results

The surfaces with the highest bacterial load in the isolation, preparatory, and worker’s rooms were the cages, hand-held sponge, and telephone, respectively. Regarding the 4 pathogens investigated, Enterococcus spp. were the most frequently isolated (11.3%), followed by E. coli (1.5%) and P. aeruginosa (1.5%). One of the P. aeruginosa isolates obtained was resistant to imipenem. In the end, new disinfection protocols were implemented, which proved to be effective in reducing bacterial counts by 99.99% in cages and the sponge, and by 90 to 99% on the telephone.

Conclusions

This study allows to conclude that the cages and the human contact surfaces were the most contaminated in the isolation rooms. Nevertheless, the new disinfection strategies seemed to be effective in reducing environmental contamination, including by some potentially nosocomial agents, although more samples must be analyzed for definitive conclusions. These results may contribute to highlight the importance of infection prevention and control measures, as fundamental tools to reduce the spread of infectious agents in the hospital environment.

Nationwide multicenter questionnaire surveys on countermeasures against antimicrobial resistance and infections in hospitals

BACKGROUND

The goals of the National Action Plan on Antimicrobial Resistance (AMR) of Japan include "implementing appropriate infection prevention and control" and "appropriate use of antimicrobials," which are relevant to healthcare facilities. Specifically, linking efforts between existing infection control teams and antimicrobial stewardship programs was suggested to be important. Previous studies reported that human resources, such as full-time equivalents of infection control practitioners, were related to improvements in antimicrobial stewardship.

METHODS

We posted questionnaires to all teaching hospitals (n = 1017) regarding hospital countermeasures against AMR and infections. To evaluate changes over time, surveys were conducted twice (1st survey: Nov 2016, 2nd survey: Feb 2018). A latent transition analysis (LTA) was performed to identify latent statuses, which refer to underlying subgroups of hospitals, and effects of the number of members in infection control teams per bed on being in the better statuses.

RESULTS

The number of valid responses was 678 (response rate, 66.7%) for the 1st survey and 559 (55.0%) for the 2nd survey. More than 99% of participating hospitals had infection control teams, with differences in activity among hospitals. Roughly 70% had their own intervention criteria for antibiotics therapies, whereas only about 60 and 50% had criteria established for the use of anti-methicillin-resistant Staphylococcus aureus antibiotics and broad-spectrum antibiotics, respectively. Only 50 and 40% of hospitals conducted surveillance of catheter-associated urinary tract infections and ventilator-associated pneumonia, respectively. Less than 50% of hospitals used maximal barrier precautions for central line catheter insertion. The LTA identified five latent statuses. The membership probability of the most favorable status in the 2nd study period was slightly increased from the 1st study period (23.6 to 25.3%). However, the increase in the least favorable status was higher (26.3 to 31.8%). Results of the LTA did not support a relationship between increasing the number of infection control practitioners per bed, which is reportedly related to improvements in antimicrobial stewardship, and being in more favorable latent statuses.

CONCLUSIONS

Our results suggest the need for more comprehensive antimicrobial stewardship programs and increased surveillance activities for healthcare-associated infections to improve antimicrobial stewardship and infection control in hospitals.

Water as a Source of Antimicrobial Resistance and Healthcare-Associated Infections

Healthcare-associated infections (HAIs) are one of the most common patient complications, affecting 7% of patients in developed countries each year. The rise of antimicrobial resistant (AMR) bacteria has been identified as one of the biggest global health challenges, resulting in an estimated 23,000 deaths in the US annually. Environmental reservoirs for AMR bacteria such as bed rails, light switches and doorknobs have been identified in the past and addressed with infection prevention guidelines. However, water and water-related devices are often overlooked as potential sources of HAI outbreaks. This systematic review examines the role of water and water-related devices in the transmission of AMR bacteria responsible for HAIs, discussing common waterborne devices, pathogens, and surveillance strategies. AMR strains of previously described waterborne pathogens including Pseudomonas aeruginosa, Mycobacterium spp., and Legionella spp. were commonly isolated. However, methicillin-resistant Staphylococcus aureus and carbapenem-resistant Enterobacteriaceae that are not typically associated with water were also isolated. Biofilms were identified as a hot spot for the dissemination of genes responsible for survival functions. A limitation identified was a lack of consistency between environmental screening scope, isolation methodology, and antimicrobial resistance characterization. Broad universal environmental surveillance guidelines must be developed and adopted to monitor AMR pathogens, allowing prediction of future threats before waterborne infection outbreaks occur.

Relocating a pediatric hospital: Does antimicrobial resistance change?

Objective

Analyze the changes in antimicrobial drug resistance patterns due to hospital relocation. To this end, we conducted a retrospective analysis of microbiological results, especially minimum inhibitory concentrations (MIC) of all isolates from blood, urine and bronchial secretions, in our pediatric university hospital before and after moving to a new building.

Results

While the number of tests done did not change, the fraction of those positive increased, more MICs were determined and certain microbes (A. baumannii, E. faecalis, Klebsiella spp. and P. mirabilis) were detected more frequently. Most changes in MICs occurred in E. faecium (increases in 8 antimicrobials, decreases only in linezolid and gentamicin). For imipenem and aminopenicillins the MICs commonly rose after relocation, the opposite is true for gentamicin and trimethoprim/sulfamethoxazole. The other factors that alter by moving a hospital such as changes in medical personnel or case severity cannot be corrected for, but using MICs we are able to provide insights into changes down to the individual antimicrobial drug and even small changes usually undetectable to the common categorical reporting of resistance.

Pseudomonas aeruginosa bacteremia among liver transplant recipients

Pseudomonas aeruginosa bacteremia remains as a life-threatening complication after liver transplantation (LT) and is intractable because of the high rate of drug resistance to commonly used antibiotics. To better understand the characteristics of this postoperative complication, PubMed and Embase searches as well as reference mining was done for relevant literature from the start of the databases through August 2018. Among LT recipients, the incidence of P. aeruginosa bacteremia ranged from 0.5% to 14.4% and mortality rates were up to 40%. Approximately 35% of all episodes of bloodstream infections (BSIs) were P. aeruginosa bacteremia, of which 47% were multidrug resistant and 63% were extensively drug resistant. Several factors are known to affect the mortality of LT recipients with P. aeruginosa bacteremia, including hypotension, mechanical ventilation, and increasing severity of illness. In LT recipients with P. aeruginosa bacteremia, alteration in DNA gyrase A genes and overexpression of proteins involved in efflux systems, namely the expression of KPC-2-type carbapenemase, NDM-1, and VIM-2-type MBL, contribute to the high resistance of P. aeruginosa to a wide variety of antibiotics. Because of complicated mechanisms of drug resistance, P. aeruginosa causes high morbidity and mortality in bacteremic LT patients. Consequently, early detection and treatment with adequate early targeted coverage for P. aeruginosa BSI are of paramount importance in the early posttransplantation period to obtain a better prognosis for LT patients.