Increased detection of carbapenemase-producing Enterobacteriaceae on post-clean sampling of a burns unit's wet surfaces

Assessing the impact of a cleaning programme on environmental hygiene in labour and neonatal wards: an exploratory study in The Gambia

BACKGROUND

Effective surface cleaning in hospitals is crucial to prevent the transmission of pathogens. However, hospitals in low- and middle-income countries face cleaning challenges due to limited resources and inadequate training.

METHODS

We assessed the effectiveness of a modified TEACH CLEAN programme for trainers in reducing surface microbiological contamination in the newborn unit of a tertiary referral hospital in The Gambia. We utilised a quasi-experimental design and compared data against those from the labour ward. Direct observations of cleaning practices and key informant interviews were also conducted to clarify the programme's impact.

RESULTS

Between July and September 2021 (pre-intervention) and October and December 2021 (post-intervention), weekly surface sampling was performed in the newborn unit and labour ward. The training package was delivered in October 2021, after which their surface microbiological contamination deteriorated in both clinical settings. While some cleaning standards improved, critical aspects such as using fresh cleaning cloths and the one-swipe method did not. Interviews with senior departmental and hospital management staff revealed ongoing challenges in the health system that hindered the ability to improve cleaning practices, including COVID-19, understaffing, disruptions to water supply and shortages of cleaning materials.

CONCLUSIONS

Keeping a hospital clean is fundamental to good care, but training hospital cleaning staff in this low-income country neonatal unit failed to reduce surface contamination levels. Further qualitative investigation revealed multiple external factors that challenged any possible impact of the cleaning programme. Further work is needed to address barriers to hospital cleaning in low-income hospitals.

Sink-traps are a major source for carbapenemase-producing Enterobacteriaceae transmission

OBJECTIVE

We studied the extent of carbapenemase-producing Enterobacteriaceae (CPE) sink contamination and transmission to patients in a nonoutbreak setting.

METHODS

During 2017-2019, 592 patient-room sinks were sampled in 34 departments. Patient weekly rectal swab CPE surveillance was universally performed. Repeated sink sampling was conducted in 9 departments. Isolates from patients and sinks were characterized using pulsed-field gel electrophoresis (PFGE), and pairs of high resemblance were sequenced by Oxford Nanopore and Illumina. Hybrid assembly was used to fully assemble plasmids, which are shared between paired isolates.

RESULTS

In total, 144 (24%) of 592 CPE-contaminated sinks were detected in 25 of 34 departments. Repeated sampling (n = 7,123) revealed that 52%-100% were contaminated at least once during the sampling period. Persistent contamination for >1 year by a dominant strain was common. During the study period, 318 patients acquired CPE. The most common species were Klebsiella pneumoniae, Escherichia coli, and Enterobacter spp. In 127 (40%) patients, a contaminated sink was the suspected source of CPE acquisition. For 20 cases with an identical sink-patient strain, temporal relation suggested sink-to-patient transmission. Hybrid assembly of specific sink-patient isolates revealed that shared plasmids were structurally identical, and SNP differences between shared pairs, along with signatures for potential recombination events, suggests recent sharing of the plasmids.

CONCLUSIONS

CPE-contaminated sinks are an important source of transmission to patients. Although traditionally person-to-person transmission has been considered the main route of CPE transmission, these data suggest a change in paradigm that may influence strategies of preventing CPE dissemination.

Genomic analysis of Citrobacter from Australian wastewater and silver gulls reveals novel sequence types carrying critically important antibiotic resistance genes

Antimicrobial resistance (AMR) is a major public health concern, and environmental bacteria have been recognized as important reservoirs of antimicrobial resistance genes (ARGs). Citrobacter, a common environmental bacterium and opportunistic pathogen in humans and other animals, has been largely understudied in terms of its diversity and AMR potential. Whole-genome (short-read) sequencing on a total of 77 Citrobacter isolates obtained from Australian silver gull (Chroicocephalus novaehollandiae) (n = 17) and influent wastewater samples (n = 60) was performed, revealing a diverse Citrobacter population, with seven different species and 33 sequence types, 17 of which were novel. From silver gull using non-selective media we isolated a broader range of species with little to no mobilised ARG carriage. Wastewater isolates (selected using Carbapenem- Resistant Enterobacterales (CRE) selective media) carried a heavy burden of ARGs (up to 21 ARGs, conferring resistance to nine classes of antibiotics), with several novel multidrug-resistant (MDR) lineages identified, including C. braakii ST1110, which carried ARGs conferring resistance to eight to nine classes of antibiotics, and C. freundii ST1105, which carried two carbapenemase genes, blaIMP-4 in class 1 integron structure, and blaKPC-2. Additionally, we identified an MDR C. portucalensis isolate carrying blaNDM-1, blaSHV-12, and mcr-9. We identified IncC, IncM2, and IncP6 plasmids as the likely vectors for many of the critically important mobilised ARGs. Phylogenetic analyses were performed to assess any epidemiological linkages between isolation sources, demonstrating low relatedness across sources beyond the ST level. However, these analyses did reveal some closer relationships between strains from disparate wastewater sources despite their collection some 13,000 km apart. These findings support the need for future surveillance of Citrobacter populations in wastewater and wildlife populations to monitor for potential opportunistic human pathogens.

Efficacy of aerosolized hydrogen peroxide (Deprox) cleaning compared to physical cleaning in a Burns Unit

BACKGROUND

The performance of Deprox aerosolized hydrogen peroxide (aHP) has not been extensively studied in real-world clinical settings. A comparative study of aHP terminal disinfection was conducted in a Burns Unit and its performance compared to physical cleaning alone.

METHODS

Environmental surfaces were sampled pre-cleaning, post-cleaning and post-aHP disinfection. Samples were cultured for MRSA, VRE, Gram-negative multi-resistant organisms and other Gram-negative bacilli.

RESULTS

310 sites were sampled. There was a reduction in the rates of contaminated surfaces post-aHP, though pathogens were still recoverable in most cases, except for VRE. There was a marked reduction in MRSA contamination of soft surfaces (12% post-clean vs 6% post-aHP), and patient room surfaces (8.3% post-clean vs 2.8% post-aHP). It does not work as well for MRSA in bathrooms: 7% of surfaces were positive post-clean, and 9% post-aHP. There was a reduction in multiresistant Gram-negative bacteria (7%-3%), mostly due to drains (33%-13%).

CONCLUSION

aHP is a useful method of environmental disinfection, especially for Gram-negative pathogens in drains and MRSA on hard and soft surfaces. Where ongoing acquisition of MRSA is a problem, an adjunctive method of terminal disinfection in bathrooms could be considered.

Genomic dynamics of species and mobile genetic elements in a prolonged blaIMP-4-associated carbapenemase outbreak in an Australian hospital

BACKGROUND

Hospital outbreaks of carbapenemase-producing organisms, such as blaIMP-4-containing organisms, are an increasing threat to patient safety.

OBJECTIVES

To investigate the genomic dynamics of a 10 year (2006-15) outbreak of blaIMP-4-containing organisms in a burns unit in a hospital in Sydney, Australia.

METHODS

All carbapenem-non-susceptible or MDR clinical isolates (2006-15) and a random selection of equivalent or ESBL-producing environmental isolates (2012-15) were sequenced [short-read (Illumina), long-read (Oxford Nanopore Technology)]. Sequence data were used to assess genetic relatedness of isolates (Mash; mapping and recombination-adjusted phylogenies), perform in silico typing (MLST, resistance genes and plasmid replicons) and reconstruct a subset of blaIMP plasmids for comparative plasmid genomics.

RESULTS

A total of 46/58 clinical and 67/96 environmental isolates contained blaIMP-4. All blaIMP-4-positive organisms contained five or more other resistance genes. Enterobacter cloacae was the predominant organism, with 12 other species mainly found in either the environment or patients, some persisting despite several cleaning methods. On phylogenetic analysis there were three genetic clusters of E. cloacae containing both clinical and environmental isolates, and an additional four clusters restricted to either reservoir. blaIMP-4 was mostly found as part of a cassette array (blaIMP-4-qacG2-aacA4-catB3) in a class 1 integron within a previously described IncM2 plasmid (pEl1573), with almost complete conservation of this cassette across the species over the 10 years. Several other plasmids were also implicated, including an IncF plasmid backbone not previously widely described in association with blaIMP-4.

CONCLUSIONS

Genetic backgrounds disseminating blaIMP-4 can persist, diversify and evolve amongst both human and environmental reservoirs during a prolonged outbreak despite intensive prevention efforts.

Dissemination of antibiotic resistance and other healthcare waterborne pathogens. The price of poor design, construction, usage and maintenance of modern water/sanitation services

Classical waterborne pathogens (cholera/typhoid) drove the development of safe water and sanitation during the industrial revolution. Whilst effective against these organisms, other bacteria exploited the potential to form biofilm in the narrow pipes of buildings. 1976 saw the discovery of legionella. Despite evidence dating back to 1967 (including paediatric deaths in Manchester in 1995 from splashes from a sink contaminating parenteral nutrition) it required the deaths of four neonates and the might of the Press in 2011 for the UK medical services to accept waterborne transmission of other Opportunistic Plumbing Premise Pathogens (OPPP). Human nature, a healthcare construction industry largely devoid of interest in water safety, and failures in recognising transmission are major forces hindering progress in preventing infection/deaths from waterborne infections. The advent of highly resistant Gram-negative bacteria is highlighting further deficiencies in modern drainage systems. These bacteria are not thought to have special adaptations promoting their dispersal but purely attract our attention to the well-trodden routes used by sensitive organisms, which go undetected. The O'Neill report warns of the bleak future without effective antibiotics. This paper examines the evidence as to why modern water services/sanitation continue to present a risk to patient safety (and the general public) and also suggests their designs may be flawed if they are to stem the modern equivalent of cholera, the dissemination of antibiotic resistance.

Can environmental contamination be explained by particular traits associated with patients?

BACKGROUND

Little is known about patient risk factors associated with environmental contamination.

AIM

To evaluate the rate of environmental contamination and to investigate individual risk factors.

METHODS

A prospective cohort study was conducted. Each day, five rooms occupied by patients were selected. Five critical surfaces were systematically swabbed twice a day before and after cleaning. Clinical characteristics of all patients were collected. Logisitic regression was performed to evaluate the association between environmental contamination and patients' characteristics.

FINDINGS

A total of 107 consecutive patients were included and 1052 environmental samples were performed. Nineteen (18%) patients were known previously colonized/infected with a multidrug-resistant organism (MDRO). Respectively, 723 (69%) and 112 (11%) samples grew with ≥1 and >2.5 cfu/cm² bacteria, resulting in 62 (58%) contaminated rooms. Considering positive samples with at least one pathogenic bacterium, 16 (15%) rooms were contaminated. By univariate and multivariate analysis, no variables analysed were associated with the environmental contamination. Considering contaminated rooms with >2.5 cfu/cm², three factors were protective for environmental contamination: known MDRO carriers/infected patients (odds ratio: 0.25; 95% confidence interval: 0.09-0.72; P = 0.01), patients with urinary catheter (0.19; 0.04-0.89; P = 0.03) and hospitalization in single room (0.3; 0.15-0.6; P < 0.001).

CONCLUSION

This study was conducted in a non-outbreak situation and showed a low rate of environmental contamination with pathogenic bacteria. Only 11% of environmental samples grew with >2.5 cfu/cm², and they were related to non-pathogenic bacteria. No risk factors associated with environmental contamination were identified.

Prevalence and dissemination risk of antimicrobial-resistant Enterobacteriaceae from shared bikes in Beijing, China

Bike-sharing as a common public transportation has been booming in China in recent years. Previous studies showed that the surfaces of public transport can act as reservoirs of antimicrobial-resistant (AR) bacteria, but AR bacterial contamination of shared bikes has not been investigated. Otherwise, the AR-Enterobacteriaceae is considered as a global health threat for humans. Herein, we aimed to investigate the prevalence of AR Enterobacteriaceae on shared bikes and examine correlations between AR Enterobacteriaceae from shared bikes and public buildings around Metro stations in Beijing. We collected 2117 samples from shared bikes at 240 Metro stations in Beijing. A total of 444 non-duplicate Enterobacteriaceae were isolated from 418 samples at 166 stations. The isolates exhibited low rates of resistance (0.5%-6.3%) to all antimicrobial agents except sulfamethoxazole-trimethoprim (31.5%). Three ceftazidime-resistant E. coli isolates were positive for bla_CTX-M-199 and two of them were positive for carbapenemase-producing gene bla_NDM-5. Multivariable logistic regression model revealed that variable "secondary/tertiary non-profit hospital nearby" was significantly (p < 0.05) associated with isolation of AR Enterobacteriaceae from the shared bikes around the Metro stations. Low AR rates of Enterobacteriaceae observed in this study suggested the risk of dissemination of AR-Enterobacteriaceae via shared bikes is limited. However, we identified hospitals as a risk factor for the dissemination of AR Enterobacteriaceae among shared bike users. More attention should be paid to both comprehensive hygiene managements in the surrounding environment of hospitals and the increasing of public awareness on the personal hygienic habits.