Clinical Studies
Small hospitals matter: insights from the emergence and spread of vancomycin-resistant enterococci in 2 public hospitals in inner Brazil

https://doi.org/10.1016/j.diagmicrobio.2015.03.026Get rights and content

Highlights

  • We studied the emergence and spread of vancomycin-resistant enterococci (VRE) in 2 public hospitals in Bauru, Brazil.

  • One of the hospitals (318 beds) provided complex, tertiary care, and the other was a small-sized facility (57 beds) for infectious diseases and chronic diseases.

  • The incidence of VRE was higher in the small-sized hospital.

  • Overall risk factors for VRE included invasive procedures and antimicrobials.

  • Strain typing showed polyclonal endemicity, with evidence of spread from the smaller to the larger hospital.

Abstract

Although vancomycin-resistant enterococci (VRE) are reported in Brazil since 1996, data on their impact over settings of different complexity are scarce. We performed a study aimed at identifying determinants of VRE emergence and spread in a public hospital consortium (comprising 2 hospitals, with 318 and 57 beds) in inner Brazil. Molecular typing and case–control studies (addressing predictors of acquisition or clonality) were performed. Among 122 authocthonous isolates, 106 were Enterococcus faecium (22 clones), and 16, Enterococcus faecalis (5 clones). Incidence was greater in the small-sized hospital, and a previous admission to this hospital was associated with greater risk of VRE colonization or infection during admission to the larger one. Overall risk factors included comorbidities, procedures, and antimicrobials (piperacillin-tazobactam, cefepime, and imipenem). Risk factors varied among different hospitals, species, and clones. Our findings demonstrate that VRE can spread within low-complexity facilities and from these to larger hospitals.

Introduction

Despite decades of extensive research, the prevention and control of multidrug-resistant organisms (MDROs) within healthcare settings are still a major challenge (Siegel et al., 2007). The difficulties multiply in developing countries, where the application of basic infection control routines is undermined by such factors as understaffing, physical structure, and poor microbiology resources (Allegranzi et al., 2011). In this context, the case for vancomycin-resistant enterococci (VRE) in Brazil is exemplary.

The first reports of VRE infection in Brazil date back from 1996 (Dalla Costa et al., 1998, Zanella et al., 1999). In the following years, VRE spread through hospitals in several Brazilian states (Bender et al., 2009, Conceição et al., 2010, da Silva et al., 2012, Moretti et al., 2011). In a recent report from a Latin American program for monitoring resistance, 27% of enterococci isolates from Brazil were VRE (Jones et al., 2013).

The epidemiology of VRE is intricate, involving cross-transmission, selection by antimicrobials, and environmental reservoirs (DeLisle and Perl, 2003). On the other hand, hospitals in Brazil vary widely in their size, complexity, and target population. In 2013, there are 6226 hospitals distributed in the vast Brazilian territory, two thirds of them with less than 50 beds (data from CNES, Brazilian's National Database of Healthcare Settings; cnes.datasus.gov.br). Many among those small-sized hospitals harbor intense surgical activity (Padoveze et al., 2010). It is therefore challenging to approach VRE epidemiology in such a variety of settings. However, that challenge is worth facing, in order to increase our understanding and identify targets for control strategies. This was the rationale of our study.

In the present study, we attempted to identify determinants of VRE emergence and spread in 2 public hospitals from a consortium: one that provides tertiary (high complexity) care and other that admits less severe medical patients. We mixed molecular strain typing and observational epidemiological designs (Foxman and Riley, 2001), in order to provide a comprehensive approach to VRE epidemiology in those settings.

In order to approach the complex epidemiology of VRE, we posed several research questions, as follows: What was the incidence of VRE in the 2 study hospitals? How were VRE clones distributed among those facilities? What were the risk factors for VRE acquisition, and how did they vary from one hospital to the other? Among VRE-harboring patients, what were the predictors for species (Enterococcus faecalis versus Enterococcus faecium) and clonality?

Section snippets

Study setting

The study was conducted in 2 hospitals in the City of Bauru, São Paulo State, Brazil (22°018′ 53″ S, 49° 03′ 38″ W). That city has approximately 360,000 inhabitants and is located 330 km away from the state capital (São Paulo City). The study hospitals are public and work as a consortium, administered by a foundation linked to Faculdade de Medicina de Botucatu (Botucatu Medical Faculty). The Hospital Estadual Bauru (HEB) is a 318-bed facility providing tertiary care for the city of Bauru and

Results

During the study period, we identified 130 subjects harboring VRE, of whom 122 were diagnosed as autochthonous for the study hospitals. Among those subjects, 109 had the first VRE isolate recovered from rectal swabs. Other 13 subjects had VRE recovered from urine (10), blood (2), and tracheal aspirate (1). Since this number was small to warrant a separate analysis, all the patients harboring VRE were analyzed as a single group.

According to the criteria discussed above, 78 and 44 patients were

Discussion

Our results can be interpreted in several levels. From a most straightforward perspective, we described the introduction and spread of VRE within 2 hospitals in inner Brazil. We typed 1 isolate from each VRE-harboring patient, ever since the first case was identified in the study setting. Strain typing revealed a progress toward polyclonal endemicity but also documented the extensive cross-transmission within and between the study hospitals. In fact, more than two thirds of isolates belonged to

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