Microbiological testing of devices used in maintaining peripheral venous catheters 1

ABSTRACT Objective: to evaluate the use of peripheral venous catheters based on microbiological analysis of devices (dressing and three-way stopcocks) and thus contribute to the prevention and infection control. Methods: this was a prospective study of microbiological analysis of 30 three-way stopcocks (external surfaces and lumens) and 30 dressing used in maintaining the peripheral venous catheters of hospitalized adult patients. Results: all external surfaces, 40% of lumens, and 86.7% of dressing presented bacterial growth. The main species isolated in the lumen were 50% coagulase-negative Staphylococcus, 14.3% Staphylococcus aureus, and 14.3% Pseudomonas aeruginosa. Fifty nine percent of multidrug-resistant bacteria were isolated of the three-way stopcocks, 42% of the lumens, and 44% of the dressing with a predominance of coagulase-negative Staphylococcus resistant to methicillin. Besides, 18% gram-negative bacteria with resistance to carbapenems were identified from multidrug-resistant bacteria on the external surfaces of the three-way stopcocks. Conclusion: it is important to emphasize the isolation of coagulase-negative Staphylococcus and gram-negative bacteria resistant to methicillin and carbapenems in samples of devices, respectively, which reinforces the importance of nursing care in the maintenance of the biologically safe environment as well as prevention and infection control practices.


Introduction
Health care in the hospital environment is constantly challenged by infections, which result in increases in morbidity and mortality, length of stay, and costs, especially considering the consumption of antibiotics and laboratory tests. Given the proportions, these infections represent one of the largest public health problems, which is aggravated by the presence of resistant strains, since they challenge scientific and technological advances and therefore catch the attention of professionals, researchers, and organizations looking for effective prevention and control measures (1)(2)(3) .
Risk factors for infection is an indicator that deserves careful analysis and elucidation in the management of aseptic techniques. This analysis represents a challenge, given variability of risks and diversity of behaviors and recommendations. In this sense, the need emerges to objectively identify the possible risks of contamination and colonization (4)(5) .
The use of intravascular catheters constitutes a vital strategy for clinical practice and effectiveness of treatments (6)(7)(8) . It is worth mentioning that peripheral venipuncture is not free of complications, since it is an invasive procedure of high frequency done most of the time in a hospital setting, which is a place that presents risks of contamination and colonization, and which requires appropriate conduct in care of catheters.
The maintenance of peripheral venous catheters is a complex topic and requires following a number of technical aseptic conformities and operational principles with a view toward safety and the prevention and control of infection.
The incidence of phlebitis and infections associated with peripheral venous catheters is relatively low, but the possibility of underestimation of data should be pointed out, especially considering the high frequency with which this procedure is done in daily routine health care. Catheter-related bacterial infections prolong hospitalization and increase the cost of treatment, besides presenting attributable mortality rates in the range between 10% to 25% (6,9) .

Inclusion criteria
The evaluation included 3WSCs used in maintaining the PVC and sterile dressing made of soft fabric backed with rayon and polyester with hypoallergenic acrylate adhesive, water-resistant, non-owcclusive, and made of hypoallergenic transparent film with vapor permeability.

Microbiological processing
The collection of biological material from the dressing was done by friction on the inner surface Rossini FP, Andrade D, Santos LCS, Ferreira AM, Tieppo C, Watanabe E.
with a swab moistened with saline solution, which was in contact with the catheter insertion site (previously defined area) for 30 seconds and in three directions.
Then the swab was transferred to a sterile test tube

Results
Of the total of 90 microbiological analyses, the samples from the lumen of the 3WSCs had growth positive levels of 40% in the TSB culture medium.
The samples from the dressing showed 86.7% of contamination and the external surface of the 3WSCs 100% (Table 1). Additionally, when the presence or absence of macroscopic dirtiness on the devices was analyzed, such as the presence of blood with bacterial growth in a TSB culture medium, it was observed that 46.6% of these samples were not considered dirty but had a positive culture for bacterial growth, 28% were considered dirty and showed positive results, 16.7% were considered dirty but were not positive, and 7.8% were not considered dirty and also were not positive.
As for the microbiological evaluation of the devices Of the total of resistant microorganisms isolated in the samples of the culture from the dressing, the two that stand out the most are coagulase-negative
In the lumen of the 3WSCs (

Discussion
The It should be noted that connections such as 3WSCs/ hubs and infusion equipment are a common gateway for microorganisms (15)    showering with a dressing that is not waterproof (8,10) . It should be pointed out that in this study the dressing was waterproof.
In the etiology of hospital infections, the presence of resistant strains has had an impact on morbidity, mortality, and costs, reaching proportions that are very worrisome (3,17) . The participation of S. aureus resistant to methicillin and of gram-negative bacilli resistant to carbapenems is increasingly frequent in episodes of bacteremia in critically ill patients (18) . Another important point is that in health institutions, the spread of resistant strains is also facilitated by noncompliance with basic recommendations such as washing hands, use of protective barriers, and decontamination of equipment, among other practices (19) .
Although there is evidence in literature of low risk of local infection of the bloodstream associated with peripheral venous catheters, this situation is changing (9) .
For this reason, one should not miss the importance of this issue, especially considering its gravity, the etiology of the microbial species, and the main predisposing factors (20)(21) .