Microbiological surveillance post-reprocessing of flexible endoscopes used in digestive endoscopy: a national study

INTRODUCTION

Microbiological surveillance of endoscopes is a safety measure for verifying the quality of reprocessing procedures and identifying contaminated devices, but duodenoscope-related outbreaks are still reported.

AIM

To assess the effectiveness of duodenoscope reprocessing procedures in Italy.

METHODS

Between December 2019 and April 2020, data obtained from microbiological surveillance post-reprocessing in 15 Italian endoscopy units were collected. Sampling was carried out after reprocessing or during storage in a cabinet. In keeping with international guidelines and the Italian position paper, the micro-organisms were classified as high-concern organisms (HCOs) and low-concern organisms (LCOs).

FINDINGS

In total, 144 samples were collected from 51 duodenoscopes. Of these, 36.81% were contaminated: 22.92% were contaminated with HCOs and 13.89% were contaminated with LCOs [2.08% with an LCO load of 11-100 colony-forming units (CFU)/device and 0.69% with an LCO load of >100 CFU/device]. The contamination rate was 27.5% in samples collected after reprocessing, 40% in samples collected during storage in a cabinet that was compliant with EN 16442:2015 (C-I), and 100% in samples collected during storage in a cabinet that was not compliant with EN 16442:2015 (NC-I). The respective HCO rates were 15.00%, 27.27% and 66.67%. Correlation between LCO contamination and storage time was demonstrated (Spearman's rho=0.3701; P=0.0026). The Olympus duodenoscope TJFQ180V demonstrated the lowest rate of contamination (29.82%), although the contamination rate was 100% for duodenoscopes stored in an NC-I cabinet.

CONCLUSION

Microbiological surveillance, along with strict adherence to reprocessing protocols, may help to detect endoscope contamination at an early stage, and reduce the risk of duodenoscope-associated infections.

Hospital-acquired Legionella infections: an update on the procedures for controlling environmental contamination

The waterborne healthcare-associated infections are mainly sustained by Legionella and Pseudomonas spp. Various water factors and plumbing characteristics, and the interaction with other water microorganisms are considered to be predictive of Legionella contamination. It is therefore mandatory to organize plans of surveillance, prevention and control in order to avoid disease appearance in immunosuppressed patients, with higher risk of death. Guidelines for the prevention of Legionnaires' disease have been published, benefiting those who face this problem, but definitive standardized solutions do not exist yet. Here we describe fifteen years of activity, during which our study group gathered interesting data on the control of Legionella contamination. Water disinfection is not generally sufficient to control the risk of infection, but a complex water safety plan should be developed, including system maintenance, training of staff and implementation of a clinical surveillance system aimed at early detection of cases. Concerning the control measures, we evaluated the effectiveness of different treatments suggested to reduce Legionella spp contamination, comparing our results with the current literature data. The performance ranking was highest for the filter, followed by boilers at high temperature, monochloramine and, at a lower level, chlorine dioxide; the effectiveness of hyperchlorination was limited, and thermal shock was even more ineffective.

Rat tenascin-R gene: structure, chromosome location and transcriptional activity of promoter and exon 1

Tenascin-R is an extracellular matrix protein expressed exclusively in the central nervous system where it is thought to play a relevant role in regulating neurite outgrowth. We have i) cloned the cDNA of the rat tenascin-R 5' region; ii) defined its genomic organization, obtaining the sequence of two novel untranslated exons; iii) mapped the gene to rat chromosome 13q23 and suggested a previously unreported synteny between rat chromosome 13q23, human chromosome 1q24, and mouse chromosome 4E; and iv) sequenced and characterized the elements responsible for its neural cell-restricted transcription. We found that two discrete regions of the rat gene (the first in the proximal promoter, the second in the first exon) are independently able to activate to a high degree the transcription of a reporter gene in either human or rat neuroblastoma cell lines but not in other cell lines. Based on this observation, we re-evaluated the arrangement of transcriptionally active regions in the human tenascin-R gene we recently cloned and found that the human gene also contains an exon sequence able to initiate and sustain transcription independently of promoter sequences.

Some effects of the stimulus repetition rate on N1 and N2 in transtympanic and surface recordings

The early auditory evoked electrical activity has been recorded in man at the promontory (transtympanic approach) and on the scalp vertex-mastoid derivation), in response to clicks delivered at different rates. Latency and amplitude of the first two peaks (N1 and N2), as a function of the repetition rate, have been measured and compared. The differences between the latencies of transtympanic and surface N1 are very small, at any rate, with a maximum value of 0.08 msec. In the transtympanic recording, the latency difference between N2 and N1 is constant throughout the whole range of rate values, from 3 to 100 clicks per second. In the surface responses, on the contrary, the latency difference between N2 and N1 tends to increase as the rate is increased. The amplitude of the transtympanic N2 is consistently reduced at click rates above 20-50 per second (more markedly than the amplitude of N1), while the amplitude of the surface N2 is much more insensitive to the rate increase. Some implications of these results are discussed with respect to the origin of N2 in the two recording conditions.

Studies on the antibacterial and antifungal properties of 1, 4-naphthoquinones

1. New halogenated 1,4-naphthoquinones were synthesized and together with other known 1,4-naphthoquinones, were screened for antibacterial activity by a turbidimetric method, and for antifungal activity by the diffusion method on agar plates.2. The half-wave potentials and the influence on the oxidative phosphorylation of some of these compounds were determined.3. 2-chloro-3,2'-chloro-ethyl-1,4-naphthoquinone (half-wave potential=-187 mV) was the most active compound, completely inhibiting cell respiration.4. While the natural active naphthoquinones, vitamin K and ubiquinones, possess, as substituent, the electron repelling methyl group, the microbiologically active 1,4-naphthoquinones are substituted, in the quinone moiety, with electron attracting groups such as OH or Cl.5. The half-wave potentials can give only an initial indication of the activity of the compounds studied; a good correlation, on the contrary, can be found between the ultraviolet spectra of such compounds and their activity which seems to depend on the ability of active compounds to exist in an extensively conjugated structure and to form hydrogen bonds.