Microbiologic assessment of the transabdominal ultrasound transducer head

Sonographers and the Fight Against Nosocomial Infections

An investigation was conducted to determine how well sonographers clean transducers and other sonography-related equipment. Previous studies have shown that cross-contamination is possible between patients during a sonogram and may lead to nosocomial infections. The potential for infecting patients is now common knowledge, so research was conducted to establish how well sonographers are sterilizing the equipment. The equipment from the sonography departments of six hospitals and clinics was tested for the presence of bacteria and fungi. Growth was present at every facility. Although only normal skin flora, including yeast, were isolated, sonographers must be more diligent in the prevention of cross-contamination in patients.

Ultrasound transducer disinfection in emergency medicine practice

Background

External ultrasound transducer disinfection is common practice in medicine. Unfortunately, clinically significant organisms, such as methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa, and Klebsiella pneumonia spread throughout healthcare facilities via direct contact despite disinfection protocols. Ultrasound transducers and coupling gel provide potential vectors for pathogen transmission, especially in immunocompromised and high-risk patient populations. Our objective was to conduct a survey to investigate the variety of cleaning solutions or sanitary wipes used and evaluate current standard practice for transducer disinfection across emergency medicine training programs in the United States.

Findings

Eighty-three academic emergency medicine programs participated in this study. Eighty-seven percent (95 % CI 80–94 %) of responding programs do not have a mandated protocol or standard contact time for transducer disinfection. Ninety percent (95 % CI 84–96 %) of institutions use disinfectant solution or disinfectant wipes, as the standard of practice, to cleanse ultrasound transducers after every use.

Conclusions

Currently, there is a great deal of variability with regard to non-endocavitary transducer disinfection protocols that seems to stem from the vast number of disinfectant products and ultrasound manufacturer disparate recommendations. In order to mitigate risk to patients and reduce health care costs linked to nosocomial infections; healthcare providers, ultrasound companies, and disinfectant manufacturers must develop a universal use disinfectant and a standard protocol for ultrasound device disinfection for noncritical device disinfection in the emergency department.

Electronic supplementary material

The online version of this article (doi:10.1186/s13756-016-0110-y) contains supplementary material, which is available to authorized users.

Ultrasound scan as a potential source of nosocomial and crossinfection: a literature review

The authors review the main concepts regarding the importance of cleaning/disinfection of ultrasonography probes, aiming a better comprehension by practitioners and thus enabling strategies to establish a safe practice without compromising the quality of the examination and the operator productivity. In the context of biosafety, it is imperative to assume that contact with blood or body fluids represents a potential source of infection. Thus, in order to implement cleaning/disinfection practice, it is necessary to understand the principles of infection control, to consider the cost/benefit ratio of the measures to be implemented, and most importantly, to comprehend that such measures will not only benefit the health professional and the patient, but the society as a whole.

Relationship between shared patient care items and healthcare-associated infections: a systematic review

BACKGROUND

Environmental surfaces may contribute to transmission of nosocomial pathogens. Noninvasive portable clinical items potentially shared among patients (NPIs) are part of the patient's immediate surroundings and may pose a threat of pathogen transmission.

OBJECTIVE

To assess the body of literature describing the range of microorganisms found on NPIs and evaluate the evidence regarding the potential for cross-transmission of microorganisms between NPIs and hospitalized patients in non-outbreak conditions.

DESIGN

A comprehensive list of NPIs was developed, and a systematic review of these items combined with healthcare-associated infection related keywords was performed.

DATA SOURCES

PubMed, Scopus, and Cochrane Library.

REVIEW METHODS

A systematic review was performed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist to identify and synthesize research reports published between January 1990 and July 2013 on studies regarding contamination of NPIs and association to infections in non-outbreak circumstances.

RESULTS

1498 records were scanned for eligibility. Thirteen studies met inclusion criteria. Overall, rates of NPI contamination ranged from 23% to 100%. Normal skin or environmental flora were found on almost all positive cultures. Potential pathogens, e.g., Staphylococcus aureus, were present on up to 86%, and Pseudomonas spp. and/or Enterobacteriaceae in 38% of positive cultures. Multi-drug resistant organisms were isolated from up to 25% of items. Three studies explored association between NPIs contamination and patient colonization and infection. One study reported 5 patients with healthcare-associated infections with pathogens found concurrently on NPIs, one found cross-transmission between patient skin bacteria and NPI contamination, and a third did not find any cross-transmission.

CONCLUSIONS

Potential pathogens and multiply resistant organisms present on NPIs in routine, non-outbreak conditions and in a variety of settings confirms the need to improve NPIs decontamination practices.

Comparison of probe disinfection procedures in routine ultrasonography: hot water versus antiseptic wiping

OBJECTIVE

It is commonly known that ultrasonography (US) transducers function as both a reservoir and means of transfer for hospital infections. The current study aimed to compare the antimicrobial effectiveness of using >80 °C water versus antiseptic wipes to disinfect US transducers.

METHODS

Subsequent to abdominal inspections in three groups of 20 patients, a swab culture was taken from the transducer in each case. Neither a mechanical nor chemical disinfection was applied to the transducer in the first group. As for the second group, the transducer was placed in >80 °C hot water for five minutes. In the third group, the transducer was wiped clean using antiseptic wipes.

RESULTS

Of the 60 swab samples collected, 40 did not produce any growth. The number of samples exhibiting growth in the first group involved 18 cases of coagulase-negative staphylococcus (CNS), as well as 15 cases of Listeria spp., one case of Corynebacterium spp. and one case of Bacillus spp., while only one case of CNS was observed in the second and third groups, respectively. The culture growth and colony forming units rate were significantly higher in the samples obtained from the first group than in those obtained from the other groups (p<0.01). As for the second and third groups, no significant differences were found in terms of the amount of colonization and growth (p=1.00).

CONCLUSION

Being a practical and a simple method for particular use in developing and underdeveloped countries, where it is hard to access relatively costly transducer disinfection materials, such as antiseptic wipes, hot water disinfection may play an active role in fighting hospital infections.

Decontamination of transvaginal ultrasound probes: review of national practice and need for national guidelines

AIM

To determine the national practice of transvaginal ultrasound (TVUS) probe decontamination in English hospitals and to develop recommendations for guidance.

MATERIALS AND METHODS

A literature review was undertaken to clarify best practice and evaluate methods of decontamination of TVUS probes. A questionnaire was developed to ascertain TVUS probe decontamination programmes in current use within English hospitals. This was sent to ultrasound leads of 100 English hospitals; 68 hospitals responded.

RESULTS

There is a wide variation in TVUS probe decontamination across English hospitals. Although the majority of respondents (87%, 59/68) reported having clear and practical written guidelines for TVUS decontamination, the frequency, methods, and types of decontamination solutions utilized were widely variable and none meet the standards required to achieve high-level disinfection.

CONCLUSION

While the decontamination of other endoluminal medical devices (e.g., flexible endoscopes) is well defined and regulated, the decontamination of TVUS probes has no such guidance. There appears to be incomplete understanding of the level of risk posed by TVUS probes, and in some cases, this has resulted in highly questionable practices regarding TVUS hygiene. There is an urgent need to develop evidence-based national guidance for TVUS probe decontamination.

Clinical review: Bedside lung ultrasound in critical care practice

Lung ultrasound can be routinely performed at the bedside by intensive care unit physicians and may provide accurate information on lung status with diagnostic and therapeutic relevance. This article reviews the performance of bedside lung ultrasound for diagnosing pleural effusion, pneumothorax, alveolar-interstitial syndrome, lung consolidation, pulmonary abscess and lung recruitment/derecruitment in critically ill patients with acute lung injury.

Evaluation of a new disinfection procedure for ultrasound probes using ultraviolet light

Following 183 ultrasound examinations, a randomized trial was conducted to compare three procedures for disinfection of probes under routine conditions: dry wiping with a soft, dry, non-sterile paper towel, antiseptic wiping with a towel impregnated with disinfectant spray and dry wiping followed by a 10 min ultraviolet C (UVC) cycle in a disinfection chamber. After ultrasonography, swabs were taken from transducer heads before and after cleaning and streaked onto plates that were then cultured. The number of colonies per plate was counted and organisms identified. The median microbial reduction was 100% for UVC, 98.4% for antiseptic wiping and 87.5% for dry wiping (P<0.001). The percentage of negative specimens was 88% for UVC, 16% for antiseptic wiping and 4% for dry wiping (P<0.0001). Microbial flora was isolated from 12 probes (6.6%) before cleaning, whereas specimens obtained after cleaning contained no pathogens except in one case after antiseptic wiping. UVC disinfection of ultrasound probe may provide a useful method for reducing the bacterial load under routine conditions.

Nosocomial outbreak of Klebsiella pneumoniae producing SHV-5 extended-spectrum beta-lactamase, originating from a contaminated ultrasonography coupling gel

Klebsiella pneumoniae resistant to ceftazidime was isolated from six adult women and two neonates hospitalized between July and November 1993 in the Department of Obstetrics and Gynecology of Boucicaut Hospital (Paris, France). The epidemiological investigation revealed a notably short delay (less than 48 h) between admission and contamination of the six adults and peripartum transmission to the neonates. The only environmental source of ceftazidime-resistant K. pneumoniae was the ultrasonography coupling gel used in the emergency room. Phenotypic (biotyping and antibiotyping) and genotypic (plasmid profile and pulsed-field gel electrophoresis) analysis of all the clinical isolates indicated the spread of a single strain. It produced SHV-5 and TEM-1 beta-lactamases, as demonstrated by isoelectric focusing and gene sequencing. The risk of cross-contamination in ultrasonography procedures is usually low and had not been associated so far with bacteria producing an extended-spectrum beta-lactamase (ESBL). Furthermore, this is the first time an epidemic of an SHV-5 ESBL-producing member of the family Enterobacteriaceae has been reported from a French hospital.