Positive cultures for S. aureus Prevalence of Nasal Carriage of Methicillin-Resistant Staphylococcus aureus among Healthcare Workers of Intensive Care Unit in Four Hospitals in Nicaragua Isabel Baldizón-Ibarra, MD1, Andrés Espinoza-Briones, MD1, Claudia Martínez-Rojas, BMLS1, Salvador Rizo-Centeno, BMLS1, Carlos Quant-Durán, MD2 and Guillermo Porras-Cortés, MD1, (1)Hospital Metropolitano Vivian Pellas, Managua, Nicaragua, (2)Hospital Roberto Calderón, Managua, Nicaragua Abstract Methods MRSA was identified in the nares of 13 HCW.(Figure 2) Background: The intensive care unit (ICU) is an high risk area for the patients. Some bacteria, such as Methicillin-Resistant Staphylococcus aureus (MRSA) are responsible for an important percentage of morbidity and mortality. It is known that healthcare workers (HCW) could be carriers of MRSA and can infect patients. In Nicaragua, there are few data about colonization of MRSA in ICU’s healthcare workers (HCW). Objective: The aim of this study is to determine the prevalence of nasal carriage of MRSA among HCW of the ICU in Hospital, Metropolitano Vivian Pellas, Bautista, Roberto Calderón and Antonio Lenin Fonseca in Managua –Capital city of Nicaragua-, from January to May 2010, as well as their association with some distinctive factors. Methods: Transversal, prolective study. Anterior nasal swabs were taken from 77 HCW and incubated in blood and McConkey Agar at 35˚C for 72 hours. Final identification of S. aureus and antibiotic susceptibility was performed with autoScan. Every procedure was performed following CLSI guidelines. Results: The prevalence of nasal carriage of S. aureus was 24.7%, and the prevalence of MRSA was 16.8%. The hospital with the highest prevalence was Hospital Roberto Calderón (26.3%). All isolated strains were susceptible to vancomycin and linezolid (100%) and most were susceptible to tretracycline (92%), while susceptibility to ciprofloxacin (30%) and clindamycin (15%) was very low. Conclusions: The prevalence of nasal carriage of MRSA among HCW in the ICU is relatively high. The obtained strains are highly resistant to antibiotics such as quinolones and clindamycin. Design: Transversal, prolective study. Setting: ICU of two private hospitals (Metropolitano Vivian Pellas and Bautista), and two hospitals of the Ministry of Health of Nicaragua (Roberto Calderón and Antonio Lenin Fonseca). HCW (physicians and nurses) of the ICU of these hospitals were recruited for the study. Method: Samples were collected from both anterior nares, transported in Amies agar, and seeded in blood agar plates. To identify the MRSA and to establish the resistance pattern, the isolates were analyzed by the MicroScan® system. The entire process was according with the CLSI guidelines. (Figure 1) All HCW n=77 Positive cultures for S. aureus N=19 (24.7%) All the MRSA strains identified in the nose of the HCW of the ICU were susceptible to vancomycin and linezolid, but were resistant at different rates to clindamycin, ciproloxacin and trimethoprim-sulfametoxazol. (Figure 4) MRSA N= 13 (16.8%) MSSA N= 6 (7.7%) Figure 2: Prevalence of nasal colonization of MRSA in HCW Results The prevalence that was found is one of the higher in comparison with other studies of prevalence of nasal carriage of MRSA in UCI’s HCW. (Table 2). 77 HCW were screened. The main characteristics are shown in the following table 1. Objective Table 2: Studies about prevalence of nasal colonization by MRSA in UCI’s HCW To determine the prevalence of nasal carriage of MRSA in HCW (physicians and nurses) of ICU in four hospitals in Managua. CHARACTERISTICS N=77 Gender Male Female 48 (62.3%) 29 (37.7%) Age (mean ± SD) 37.8 ± 8.1 years Hospital Distribution H. Roberto Calderón H. Antonio L. Fonseca H. Bautista H. Metropolitano V. Pellas 30 (39%) 27 (35%) 10 (13%) Type of HCW Postgraduate physician Resident physician Registered nurse Assistant nurse 16 (20.7%) 18 (23.4%) 14 (18.2%) Number of years working in ICU (mean ± SD) 5.7 ± 6.2 years Upper respiratory infection in the previous 6 months 49 (63.3%) Use of antibiotics in the previous 4 months 27 (35.1%) Studies Country Prevalence Fadeyi ,2010 Nigeria 39.9% Zorgani, 2009 Libya 36.8% Baldizón, 2010* Nicaragua 16.8% Londoño, 2006 Colombia 15% Aurenty, 2010 Venezuela 13% Askarian, 2009 Iran 9.1% Montalvo, 2009 Peru 7.3% Debbi, 2008 USA 4.5% Johnston, 2007 2% Mathanraj, 2009 India 1.8% Figure 4: Susceptibility of strains of MRSA Conclusions MRSA nasal carriage among HCW has become an important issue. This study has revealed one of the highest prevalence of nasal carriage of MRSA in HCW of ICU. The susceptibility pattern demonstrated a resistance pattern to clindamycin, ciprofloxacin and TMP-SMX. There Was not found any association to previous respiratory infection or use of antibiotics. *Present study Figure 1: Samples from the nares of the HCW were transported in Amies agar tubes, and then blood agar plates were inoculated. Microscopic observation was done at the first. MRSA were identified using MicroScan® system HCW of ICU in Hospital Roberto Calderon –one of the largest hospital in the capital city of Managua- had the highest prevalence of colonization by MRSA (26.6%). (Figure 3) Corresponding author: Isabel Baldizón-Ibarra MD, isabelbaldizon@gmail.com, Hospital Metropolitano Vivian Pellas Km. 9 ¾ crta. a Masaya. Managua, Nicaragua.