Nosocomial Infection in an Intensive Care Unit in a Brazilian University Hospital

This prospective study aimed to determine the nosocomial infection (NI) incidence in an Intensive Care Unit (ICU), its association with clinical characteristics and occurrence sites. It was carried out among 1.886 patients admitted in an ICU of a University Hospital, from August 2005 to January 2008. Data analysis was done using Fisher’s test and Relative Risk (RR). There were 383 NIs (20.3%). The infections were in the urinary tract (n=144; 37.6%), pneumonia (n=98; 25.6%), sepsis (n=58; 15.1%), surgical site (n=54; 14.1%) and others (n=29; 7.7%). Hospitalization average was 19.3 days for patients with NI and 20.2 days for those with colonization by resistant microorganisms. The mortality was 39.5% among patients with NI (RR: 4.4; 3.4-5.6). The NI was associated with patients originated from other units of the institution/emergency unit, more than 4 days of hospitalization, community infection, colonized by resistant microorganisms, using invasive procedures and deaths resulting from NI.


Introduction
The 21 st century reveals a new healthcare scenario as result of scientific and technological progress.New infectious agents are documented and infections resurged with new strength (1) , especially in Intensive Care Units (ICU).Nosocomial infections (NI) are more severe in these high technology hospital units which hold acutely ill patients needing intensive life support (1)(2)(3) .ICU nosocomial infections are primarily related to the patient's health status, invasive device utilization such as venous central line, long term urinary catheterization and mechanical ventilation, use of imunosupressors, prolonged hospitalization, colonization by resistant microorganisms, antibiotics prescription and the setting itself which propitiate bacterial natural selection (2)(3)(4)(5) .
ICU nosocomial infection rate varies from 18 to 54%, five to ten times higher than other hospital units' rates.It is responsible for 5 to 35% of all NI and for approximately 90% of all outbreaks of diseases in an ICU (2)(3)(6)(7) . The IU high mortality rates, commonly ranging from 9 to 38%, can reach 60% due to nosocomial infection occurrence (5,8) .
This study aimed to determine the nosocomial infection incidence in an ICU, its association with clinical characteristics (gender, age, provenance, medical profile, ICU length-of-stay (days), community infection, colonization by resistant microorganisms, invasive devices use, and deaths) and occurrence sites.
As secondary objective, the study aimed to identify the more common microorganisms responsible for NI and their resistance status.
Results of the present study contribute to support results of other studies on NI and may serve as comparison with other health establishments' NI rates.
The study adds knowledge on ICU infection rate and emphasizes the importance of performing the control of its related outcomes.

Material and methods
The study design was prospective, descriptive and epidemiological.Data was collected in an adult ICU of a University Hospital.The Unit has 18 beds, among which two are specially equipped for patient isolation.Nosocomial Infection Surveillance System (NISS) were used (9)(10)(11) as follows: -Community infections: all notified infections at the patient's ICU admittance, whether the infection have appeared in another hospital, another hospital ward or outside any hospital establishment; -Surgical patients: patients who underwent any surgical procedure, with incision and suture, including videolaparoscopy, in an Operation Room; -Colonization by resistant microorganisms: isolation identified by laboratorial culture.The notification of colonization/infection by resistant microorganisms is a routine at the study hospital according to this criteria: patients from the emergency unit, patients transferred from other hospitals with hospitalization greater or equal than 72 hours or patients from the own hospital transferred to the ICU with prior stay greater or equal than seven days (12) ; -Nosocomial infection: any notified infection in an ICU,

Demographic characteristics of the sample
A total of 1.889 patients were admitted in the ICU during data collection, and 1.886 (99.3%) were eligible for the study.Table 1 presents demographic and clinical data of the sample.
The overall average for the ICU stay was 5.7 days (median= 3 days).The average for patients who did not acquire NI was 3.7 days (median= 3 days) and 19.3 days (median= 13 days) for those who had NI.For the non-colonized patients, the average ICU stay was 3.8 days (median= 3 days) and 20.2 days (median= 14 days) for those colonized by resistant microorganisms.
The averages of days under the devices were 5.2, 6.6 and 5.3, respectively.
Rev. Latino-Am.Enfermagem 2010 Mar-Apr; 18(2):233-9.were hospitalized at the studied hospital prior to admission in the ICU, and among them 177 (16.5%) developed NI.Those transferred from the hospital emergency unit were more likely to acquire infection (RR: 2.6; CI: 1.8-3.7,p<0.05), than those who came from the community.Also, a relative risk of 1.9 (CI: 1.4-2.4,p<0.05) was verified for those who came from another units within the hospital, when compared with those who came from the community.
As reported by other studies in the field, the length-of-stay for more than four days, the episode of community infection, the colonization by resistant microorganisms, and the use of invasive devices were significantly associated with the occurrence of NI, with high relative risks indexes (more than 2.4).Furthermore, among the 195 deaths in the ICU during the study, 77 patients (39.5%) had developed NI. between longer hospitalization and infection (7,9,15) .

Studies report that patients with any infection diagnosis by
Patients who were derived within and hospitalized prior to ICU admission had a risk of 1.93 (CI: 1.48-2.49) higher for acquiring NI in the ICU when compared to those admitted from the community.Consistent with our findings, results of studies developed in North America, using similar sample, showed double risk for developing ICU nosocomial infection for patients transferred from an emergency room or other hospital unit than those who came from the community, or from another hospital (13)(14) .
the ICU admission had higher risk of developing NI in the Unit compared with those who did not have prior infection (RR: 0.25; CI: 0.07-0.86;p <0.05) (16) .
Patients colonized by resistant microorganisms evidenced a high NI rate (61.6%) and had a relative risk of 9.5 (CI: 7.7-11.7;p <0.05) when compared with those who did not have colonization by the resistant microorganisms.In the sample were isolated 343 cases of colonization (an average of 1.5 per patient), by 13 Researchers report that urinary tract infection (UTI) associated with long term urinary catheterization accounts for 8 to 35% of all ICU infections.The most prevalent urinary infection found in the studies were asymptomatic bacteriuria (4,8,14) .In the present study, UTI were responsible for 37.6% (n=144) of all reported ICU infections, among which 76.4% (n=110) were asymptomatic and 33.6% (n=34) were symptomatic.

NNIS (National Nosocomial Infections Surveillance
System) data indicates that pneumonias account for 31% of all ICU infections.Some authors believe that nosocomial pneumonia is the second commonest NI and the most common NI cause of death.This is consistent with results of the present study, where pneumonia was present in 25.6% (n=98) of NI, however less common than UTI (8,(17)(18) .
Among the 195 deaths (10.3%), 39.5% (n=77) were patients who developed NI, a datum consistent with findings of others researches that found a positive relation between higher mortality rates and NI diagnosis (5,(7)(8) .
Based on our findings, we suggest periodical

Conclusion
Nosocomial infection rate was 20.3% in 246 patients.
The ICU NI rate in the present study was consistent with the literature.The commonest infection was in the Staff team is composed by 10 medical doctors and four residents, four physical therapists, 12 registered nurses and 71 licensed nurses, a total of 101 healthcare professionals.Almost all (90%) of all admissions are paid by the Unified National Health System and the remainder are paid by private health insurances or by the own patient.The sample included all the patients who were admitted in the ICU from August 2005 to January 2008 (N=1.889).Exclusion criteria was uncompleted medical records (n=03).Definitions from the National after 48 hours of admission in the Unit, or 48 hours after patient's discharge.Urinary tract infections which appear up to seven days after discharge and are associated with long term catheterization are considered NI as well.Before data collection, the research was approved by the institutional review board, protocol 267/2003, in compliance with Resolution 196/96 of the National Health Council, which regulates research involving human subjects.Data were collected by a trained nursing undergraduate student, from medical charts and patients' microbial count.The collected data included gender, age, origin, medical profile, ICU length-of-stay, community infection, colonization during the stay in the ICU by resistant microorganisms, invasive device utilization, nosocomial infection, deaths and NI´ occurrence sites.Data were entered in the Statistical Program for Social Sciences (SPSS, version 13.0) and analyzed using Fisher's Exact Test to verify association of the NI with clinical characteristics and demographic variables, and Relative Risk (RR).Confidence Interval (CI) of 95% and statistical significance of 0.05 was established.
discussions among the healthcare team about NI rates, resistant microorganism profile at the institution, and mortality rate associated with them, in seminars, clinical meetings, or training sessions.Moreover, to encourage team participation and raise awareness about the importance of NI prevention campaigns.Those activities can contribute to healthcare management, allow an overview of tendencies and fluctuations of infections, and provide information for the creation and review of protocols.
Urinary tract, followed by pneumonia, sepsis, surgical site infection and others (vascular, eye, ear, mouth, nose and throat, skin, reproductive and gastrointestinal systems).The average hospitalization was 19.3 days for patients with NI and 20.2 days for those with colonization by resistant microorganism.The mortality rate was 39.5% among patients with NI (RR: 4.4; 3.4-5.6).The NI was associated with patients originated from other units of the institution/emergency unit, more than 4 days of hospitalization, community infection, colonized by resistant microorganisms, using invasive devices and deaths resulting from NI.The most common non resistant microorganisms responsible for the NI were Candida albicans, Escherichia coli and Pseudomonas aeruginosa.And those identified as most frequent multi-drug resistant microorganisms causing NI were Acinetobacter baumannii and Pseudomonas aeruginosa.The results of this study contribute to support other studies on NI, and reaffirm the importance of an effective program for infection control with the involvement of healthcare workers.The study adds knowledge on ICU infection rate and emphasizes the importance of performing the control of its related outcomes such as patient risk, mortality and occurrence of resistant microorganisms.

Table 1 -
Distribution of the sample according to the study variables, (Aug.2005-Jan.2008).Brazil, 2008The distribution of the patients with and without infection is shown in Table2.Most patients (n=1.075) * Home discharge, discharge to other wards or hospital transference.SD: Standard deviationNosocomial infections incidence and patients outcomesThe ICU nosocomial infection rate was twenty percent (383 NIs); there were 246 (13.0%) patients infected and approximately 10% (n=195) of the patients died.Subtitle: UTI: Urinary Tract Infections; PNM: Pneumonia; SSI: Surgical Site Infections; CVS: Cardiovascular; EENT: Eye, Ear, Nose and Throat, REPR: Reproductive; GI: Gastrointestinal.Figure 1 -Distribution of the Intensive Care Unit Nosocomial Infections, according to the type of infection, (Aug.