Bacterial biofilm prevalence in dental unit waterlines: a systematic review and meta-analysis

BACKGROUNDS

Numerous studies have shown that dental unit water lines (DUWLs) are often contaminated by a wide range of micro-organisms (bacteria, fungi, protozoa) and various prevalence have been reported for it in previous studies. Therefore, this review study aims to describe the prevalence of bacterial biofilm contamination of DUWLs.

METHODS

This is a systematic review and meta-analysis in which the related keywords in different international databases, including Medline (via PubMed) and Scopus were searched. The retrieved studies were screened and the required data were extracted from the included studies. Three standard methods including American Dental Association (ADA), The Center for Disease Control and Prevention (CDC) and contaminated > 100 CFU/ml(C-100) standards were used to assess the bacterial biofilm contamination of DUWLs. All studies that calculated the prevalence of bacterial biofilm contamination of DUWLs, and English full-text studies were included in the meta-analysis. Studies that did not have relevant data or used unusual laboratory methods were excluded. Methodological risk of bias was assessed by a related checklist and finally, the data were pooled by fixed or random-effect models.

RESULTS

Seven hundred and thirty-six studies were identified and screened and 26 related studies were included in the meta-analysis. The oldest included study was published in 1976 and the most recent study was published in 2020. According to the ADA, CDC and C-100 standards, the prevalence of bacterial contamination was estimated to be 85.0% (95% confidence interval (CI): 66.0-94.0%), 77.0% (95%CI: 66.0-85.0%) and 69.0% (95%CI: 67.0-71.0%), respectively. The prevalence of Legionella Pneumophila and Pseudomonas Aeruginosa in DUWLs was estimated to be 12.0% (95%CI: 10.0-14.0%) and 8.0% (95%CI: 2.0-24.0%), respectively.

CONCLUSION

The results of this review study suggested a high prevalence of bacterial biofilm in DUWLs; therefore, the use of appropriate disinfecting protocol is recommended to reduce the prevalence of contamination and reduce the probable cross-infection.

Investigating Particulate Production in The Operating Suite Following the Use of Waterless Alcohol Based Dry Scrub Versus Traditional Hand Washing and Drying with Commonly Used Surgical Towels: An Experimental Study

BACKGROUND

An often-overlooked item that could cause contamination in the operating suite are the towels used for hand drying following surgical scrub. The purpose of this current study was to determine if there was a difference in the particulate count from different hand drying methods following surgical hand preparation.

METHODS

Three simulated hand drying groups were established: disposable sterilized surgical towels, reusable sterilized surgical towels, and a waterless alcohol-based dry rub. Particle size measurements of 0.3 µm, 5.0 µm, and 10.0 µm were collected at time zero and repeated every minute for 5 minutes for a total of 10 trials each.

RESULTS

Both the reusable and disposable towels produced significantly more particle matter in all size groups compared to the alcohol scrub control group. A comparison analysis and ANOVA testing demonstrated that alcohol dry scrub produced significantly fewer particles compared to both the disposable blue towels (P<0.01) and the reusable green towels (P<0.01). Disposable towels produced significantly more particles in the 0.3 µm count compared to reusable towels (P<0.05).

CONCLUSIONS

An alcohol-based dry rub without using a towel yielded the lowest amount of particulate formation in this experimental model, while reusable surgical towels produced the highest number of particles.

LEVEL OF EVIDENCE

Level II Experimental Study.

Polymerase Chain Reaction/Rapid Methods Are Gaining a Foothold in Developing Countries

Detection of microbial contamination in pharmaceutical raw materials and finished products is a critical factor to guarantee their safety, stability, and potency. Rapid microbiological methods-such as polymerase chain reaction-have been widely applied to clinical and food quality control analysis. However, polymerase chain reaction applications to pharmaceutical quality control have been rather slow and sporadic. Successful implementation of these methods in pharmaceutical companies in developing countries requires important considerations to provide sensitive and robust assays that will comply with good manufacturing practices.

LAY ABSTRACT

In recent years several publications have encouraged the application of molecular techniques in the microbiological assessment of pharmaceuticals. One of these techniques is polymerase chain reaction (PCR). The successful application of PCR in the pharmaceutical industry in developing countries is governed by considerable factors and requirements. These factors include the setting up of a PCR laboratory and the choice of appropriate equipment and reagents. In addition, the presence of well-trained analysts and establishment of quality control and quality assurance programs are important requirements. The pharmaceutical firms should take into account these factors to allow better chances for regulatory acceptance and wide application of this technique.

Bacterial contamination of hospital-prepared enteral tube feeding formulas in Isfahan, Iran

BACKGROUND

Hospital-prepared tube feedings from three intensive care units of two hospitals in Isfahan, Iran were analyzed for microbial contamination.

METHODS

A total number of 152 samples (76 samples each at the time of preparation and 18 hours following preparation) were collected. Standard plate count, coliform count and Staphylococcus aureus count for all samples were conducted. Samples were analyzed also for the presence of Salmonella spp. and Listeria spp.

RESULTS

At the time of food preparation, out of 76 samples, 53 samples (70%) had coliform contamination and 87% of these contaminated samples had counts greater than 10(1) cfu/g. Also, 68 samples (90%) had S. aureus contamination greater than 10(1) cfu/g. In standard plate count, 74 samples (97%) had counts greater than 10(3) cfu/g, while 54 samples (71%) had counts greater than 10(4) cfu/g. In second sampling occasion, out of 76 samples, 68 samples (90%) had coliform contamination and 84% of these contaminated samples had counts greater than 10(1) cfu/g. Also, 72 samples (95%) had S. aureus contamination, 98.6% of these contaminated samples had counts greater than 10(2) cfu/g. In standard plate count, 74 samples (97%) had counts greater than 10(4) cfu/g. No Salmonella or Listeria was detected from samples.

CONCLUSIONS

The results indicated that a majority of the blenderized enteral tube feedings in those hospitals are not safe. In comparison to the standard limits, these enteral tube feedings are highly contaminated and posed substantial risk for developing a foodborne disease or nosocomial infection.