Hormigas (Hymenoptera: Formicidae) en hospitales del sur de Brasil

JUNIR ANTONIO LUTINSKI¹, CAROLINA CHARLIER AHLERT², BIANCA RIBEIRO DE FREITAS³, MAURA MOREL TRAUTMANN⁴, SIMONE PIROTTA TANCREDO⁵ and FLÁVIO ROBERTO MELLO GARCIA⁶

¹Dr. Graduate Program in Health Sciences at the Community University of Chapecó Region (Unochapecó). Av. Senador Attílio Fontana, 591-E, Efapi - Cep:89809-000, Caixa Postal: 1141. SC, Brazil. junir@unochapeco.edu.br. Corresponding author.
²Biologist. Quality Coordination of Antinsect Desinsetizadora e Produtos Químicos Ltda. carolina@antinsect.com.br.
³Biologist. Biological Sciences Course at the Lutheran University of Brazil. (ULBRA). bianca@antinsect.com.br.
⁴Biologist. Biological Sciences Course at the Lutheran University of Brazil (ULBRA). maura@audiostock.com.br.
⁵Specialist, Biologist. Vector control area and urban pests at the company Antinsect Desinsetizadora e Produtos Químicos Ltda. s.pirotta@gmail.com.
⁶Dr. Graduate Program in Entomology at the Federal University of Pelotas (UFPel) and Graduate Program in Agricultural Sciences at UDELAR (Uruguay). flavio.garcia@ufpel.edu.br

Key words: Vector control. Hospital infection. Infestation. Nylanderia. Public health.

Resumen: Las hormigas están entre los organismos mejor adaptados a los entornos urbanos. Las que se encuentran en los hospitales han recibido más atención y se han descrito como vectores importantes de organismos patógenos. Este estudio tuvo como objetivo comparar la riqueza y abundancia de hormigas en cuatro hospitales en el sur de Brasil y analizar la asociación de especies en diferentes ambientes hospitalarios. Se tomaron muestras de cuatro tipos de ambientes: unidades de cuidados intensivos (UCI), centros de nutrición, enfermerías y almacenes. La riqueza de muestreo en cada una de las cuatro condiciones se comparó usando un análisis de rarefacción basado en el número de ocurrencias. Para evaluar la asociación entre las especies de hormigas con ambientes hospitalarios, se construyó un Análisis de Componentes Principales (PCA). Se identificaron 20 especies. El sector de la nutrición fue el ambiente con la mayor riqueza (S = 14), seguido de las enfermerías (S = 7), almacenes (S = 7) y las salas de UCI (S = 4). Cinco especies se asociaron con los ambientes evaluados, entre ellos,Nylanderia fulva y Nylanderia fulva.  Este resultado puede servir como una advertencia a las autoridades de los hospitales sobre los riesgos de transmisión mecánica de agentes patógenos por hormigas en ambientes hospitalarios.

Palabras clave: Control de vectores. Infección hospitalaria. Infestación. Nylanderia . Salud pública.

Introduction

Ants are one of the most common insect families (Holldobler and Wilson 1990) and are characterized by wide distribution, richness and abundance in terrestrial ecosystems (Alonso and Agosti 2000). They are among the organisms best adapted to urban environments (Braganga and Lima 2010) and can settle in locations that have hostile environmental conditions for survival (Lutinski et al. 2014). In the last decade, the ants found in urban areas have received more attention and been the focus of research in hospital settings, where some species have been described as important vectors of pathogens, threatening human health (Moreira et al. 2005; Costa et al. 2006; Lise et al. 2006; Garcia et al. 2011).

Part of the success of ants in urban environments is due to ability that many species have to find food and places to nest near or inside the buildings constructed by humans (Soares  et al. 2006). Some species have become synanthropic. Polygynous species may suffer the fragmentation of their colonies which enhances its spread and colonization of urban environments and further complicates the population control of those considered pests or capable to carry pathogens (Bueno and Campos-Farinha 1998).

Approximately 2,000 species of ants are found in Brazil and of these about 20 are considered pests in urban environments (Bueno and Campos-Farinha 1999). Damage caused by the ants range from simple bites that can trigger allergic reactions to serious public health problems when they convey pathogenic microorganisms in health facilities such as clinics, hospitals and emergency care units (Lise  et al. 2006; Santos et al. 2009). Ants that nest in the area outside of hospitals can carry viruses, bacteria, protozoa, fungi and helminth eggs in their bodies and can contaminate food, equipment and utensils when they come into hospital settings (Bueno and Campos-Farinha 1998; Pereira and Ueno 2008; Braganga and Lima 2010). Bacteria such as  Staphylococcus, Acinetobacter, Streptococcus, Enterococcus and Enterobacter have been isolated from ants sampled in hospitals, which highlights the risk to public health that some species may represent (Fowler et al. 1993; Lise et al. 2006; Rodovalho et al. 2007; Pesquero et al. 2008).

The ant fauna found in hospital settings is not rich compared to other types of Brazilian urban environments (Lutinski  et al. 2014). However, some taxa such as Tapinoma melanocephalum (Fabricius, 1793), Paratrechina longicornis (Latreille, 1802),Nylanderia fulva (Linnaeus, 1758),  Nylanderia fulva (Mayr, 1862), Wasmannia auropunctata (Roger, 1863) and species of Camponotus, Solenopsis and  Pheidole occur more frequently in studies (Bueno and Fowler 1994; Bueno and Campos-Farinha 1999; Soares et al. 2006; Garcia et al. 2011). The number of ant species sampled in hospitals may be linked to the size of the sampling effort involving only indoors, or outdoors also, to the size of the hospital areas (Bueno and Fowler 1994) and condition of conservation of buildings (Soares et al. 2006).

Inside the hospital area, the ants have been sampled in many different types of environments such as of pediatrics wards, intensive care units (ICUs), infirmaries, oncology sectors, surgery rooms, emergency care sectors and nutrition sectors (Bueno and Campos-Farinha 1999; Lise et al. 2006; Rodovalho et al. 2007; Garcia et al. 2011). However, literature lacks studies to identify the hospital environments more susceptible to the presence of ants and relating the frequency of the most abundant species with certain hospital environments. In this perspective, this study proposes: 1) to increase knowledge about the occurrence of ants in hospital environments; 2) to compare the richness and abundance of ants in four types of hospital environments, and; 3) to determine the association between more abundant species of ants with the sampled hospitals.

This study was conducted in four hospitals in southern Brazil. Hospitals included in the sample are located in the state of Rio Grande do Sul, in the cities of Alvorada (medium size: 91 beds) Canoas (large: 417 beds), Esteio (medium size: 133 beds) and Sapucaia do Sul (large size: 211 beds) (Fig. 1).

Sampling. Samplings were carried out monthly, from May 2007 to April 2008. They were conducted during the day between 09:00 and 17:00 hours. We focused on four types of rooms: wards of intensive care units (ICUs), nutrition center, infirmaries and warehouses. Inspections at these sites were performed, actively seeking ants. The use of attractive baits was discarded, since the objective was to identify the species naturally occurring in the environment, without any attractive component when sampling (Oliveira and Campos-Farinha 2005). For capturing ants a rod with cotton wool was used, and the samples were placed in vials containing 70% alcohol. Each sample was labeled with date, place of sampling and collector and forwarded to the Entomology Laboratory of Unilasalle for screening. The identification of the samples was carried out in the Entomology Laboratory of the Community University of the Region of Chapecó (Unochapecó), based on Fernández identification keys (2003) and Bueno and Campos-Farinha (1999). These were then compared with the specimens deposited in the Entomological Collection of the same university.

Statistical analysis. In each type of sampled hospital setting, data included only the presence or absence of the species in the samples and not the number of specimens (Zarzuela et al. 2002).

In order to display the richness of ants sampled in each hospital and to characterize the most abundant species, a table showing the relative frequency of species in each hospital was built (Lise et al. 2006). The richness of ants of each of the four environments of each hospital was compared in through a rarefaction analysis based on the number of occurrences (Gotelli and Colwell 2001). This analysis was performed using the software Ecosim 7 (Gotelli and Entsminger 2001), which allows comparisons between sets of samples (Melo et al. 2003).

The association of ant species sampled with the hospital environment was tested through a Principal Component Analysis (PCA). Seven species were excluded from this analysis due to the small number of occurrences in the study (<= 2). The data were previously transformed into Log (x + 1) and analyzed with the aid of the statistical program Past (Hammer et al. 2001).

Results

A number of 1,899 ants were sampled and it was recorded. It was identified a total richness of 20 species, belonging to five subfamilies, seven tribes and 10 genera. In the hospital of Canoas, it was identified the greatest richness (S = 13), followed by the hospital in Sapucaia do Sul (S = 9), the hospital in Esteio (S = 4) and the hospital in Alvorada (S = 3). The most frequently sampled species in hospitals were: Alvorada: Pheidole sp. 4 (76.8%) and Pheidole sp. 1 (22.8%); Canoas:Nylanderia fulva (37.6%) and Pheidole sp. 4 (29.6%); Esteio: Nylanderia fulva (67.9%) and Pheidole sp. 1 (30.8%); Sapucaia do Sul: Brachymyrmex sp. (64.1%) and  Paratrechina longicornis (16.2%) (Table 1).

The occurrences of the species Camponotus diversipalpus Santschi, 1922, Dorymyrmex sp., P longicornis, Pheidole sp. 2, Pheidole sp. 3, Pheidole sp. 5, Pheidole sp. 6, and  Solenopsis sp. are independent of the type of the sampled environment. The principal component analysis (Fig. 3) showed a strong association of the species Pheidole sp. 4 with the nutrition sector, Pheidole sp. 1 with the sector of warehouses, Brachymyrmex sp. andM. pharaonis with the sector of infirmaries and N. fulva with the sectors of nutrition and warehouse.

Discussion

The richness of ants obtained in this study is higher than that seen in other studies done in hospitals of southern Brazil, such as Lise et al. (2006) in Chapeco (SC), Bicho  et al. (2007) in Bage (RS) and Garcia et al. (2011) in Porto Alegre (RS). Of all environments, the nutrition department was the most infested, followed by the environments of the infirmaries, warehouse and at the other end, the environment of the ICUs. Five species were associated with the evaluated environments, among them, M. pharaonis and N. fulva.

The Pheidole genus was the one which had the highest diversity (S = 7), or 35% of the total number of species.  Pheidole sp. 1 was the only species occurring in the four hospitals. The occurrence of species of this genus totaled 99.6% in the hospital in Alvorada, 39.1% in the hospital in Canoas, 31.3% in the hospital in Esteio and only 1% of cases in the hospital of Sapucaia do Sul. The species of this genus build their nests in walls and floors of human constructions, taking advantage of defects or structural failure (Silva and Loeck 2006). The occurrence of species of Pheidole in hospital settings has been reported in other studies involving hospital settings (Lise et al. 2006; Bicho et al. 2007; Gazeta  et al. 2007; Pesquero et al. 2008; Santos et al. 2009; Garcia  et al. 2011).

Nylanderia fulva was present in three of the four hospitals, and was also one of the most frequent in the study. At the hospital in Canoas, its frequency was 21.6%; in Esteio, it reached 67.9% and in Sapucaia do Sul, 8.4%. Other species of the tribe Plagiolepidini, Brachymyrmex sp. and P. longicornis occurred only in one hospital (Sapucaia do Sul) with a frequency of 64.1% and 16.2%, respectively. Both species of genera Nylanderia and Paratrechina are often registered in faunal studies of urban environments ants. Paratrechina fulva and P. longicornis are important pests infesting homes and hospitals (Fowler et al. 1993; Zarzuela et al. 2002). Ants of the genus Brachymyrmex sp. nest in crevices tiles, plugs and small cracks or crevices in floors and walls of buildings. They are common in hospital settings (Oliveira and Campos-Farinha 2005; Lise et al. 2006).

Monomorium pharaonis was registered in two hospitals Canoas (37.6%) and Sapucaia do Sul (9.4%). This species is distributed virtually in all continents (Olaya-Masmela  et al. 2005) and make nests in cavities and in homes; its ability to disperse pathogens was proven by Eichler (1990) and Zarzuela et al. (2002). Its frequency in hospitals can be attributed to their habits and ecological characteristics. It is a dominant species in this type of environment and exhibits rapid colony growth (Bueno and Campos-Farinha 1999; Campos-Farinha et al. 2002).

We highlight the diversity of the genus Camponotus (S = 5) in the evaluated hospitals. At the hospital in Alvorada a species ( C. diversipalpus) was recorded; in the hospital in Canoas two were recorded ( C. mus and C. rufipes) and in the hospital in Sapucaia do Sul, two species were also recorded (C. crassus and Camponotus sp.). Despite the low frequency in hospitals, some species of Camponotus have the habit of building their nests in the very building, such as in wooden ceilings, door frames and windows and even in electronics (Campos-Farinha et al. 2002). Species of this genus are considered important mechanical vectors of pathogens in hospitals (Zarzuela et al. 2002; Lise et al. 2006; Santos et al. 2009).

The activities, materials and products present in each type of hospital environment may be related to the richness of ants associated with each. The results of this study show that the richness differs significantly from one environment to another. Being the hospital a place where as much attention to hygiene and the risk of transmission of pathogens between patients should prevail, the occurrence of any vector, ant or another, is undesirable. However, the presence of food in the sectors of nutrition may be attracting them and explain a greater number of ant species found in this type of environment. The transit of materials, food and products in the infirmary wards and warehouses may explain the presence of ants, even in a smaller number of species than in nutrition environments. Among the evaluated environments, UTIs are those where it is expected that the greatest care to the dispersal of pathogens. However, the occurrence of four species (Pheidole sp. 1, Pheidole sp. 2, Pheidole sp. 4 and Pheidole sp. 5) in this type of environment is indicative of carelessness with the relevant health standards to the environments of this nature.

The generalist characteristics of the genus Pheidole (Silvestre et al. 2003) may explain the association of  Pheidole sp. 4 with the sector of nutrition and Pheidole sp. 1 with the sector of warehouses. The possible presence of food scraps on the floor or dumps in these environments may be attracting these ants to these food sources. The small size of the species Brachymyrmex sp. andM. pharaonis (Oliveira and Campos-Farinha 2005; Silvestre et al. 2003) may indicate that these species are finding places to nest in the sectors of the infirmaries. It also represents the adaptation of these species to cohabitate in human constructions (Zarzuela  et al. 2002). Nylanderia fulva is a common species in urban environments in southern Brazil (Lutinski et al. 2014). It is generalist (Silvestre et al. 2003) and invades indoors during their foraging. Possible sources of food in the sectors of nutrition and warehouse may explain the association of this species with these environments.

This study extends the knowledge about the occurrence of ants in hospital environments of southern Brazil. The record of 20 species of ants in four hospitals is one of the largest riches ever sampled in this type of establishment. This result can serve as a warning to the hospital authorities about the risks of mechanical transmission of pathogens in hospitals and health risks to patients undergoing treatment. It was also found that the ant fauna varies in richness, composition and abundance of a type of hospital to another. The presence and handling of food as found in the nutrition sector may be attracting the ants into the hospitals. The study also showed that some species of ants may be finding easier to colonize certain hospital environments than others.

Acknowledgements

To the directions of sampled hospitals for permission to carry out the sampling.

Literature cited

ALONSO, L. E.; AGOSTI, D. 2000. Biodiversity studies, monitoring and ants: an overview. pp. 1-8. In: Agosti, D.; Majer, J. D.; Alonso, L. E.; Schultz, T. R. (Eds.). Ants: standard methods for measuring and monitoring biodiversity. Smithsonian Institution. Washington. USA. 280 p.         [ Links ]

BICHO, C. L.; BRANCAO, M. L. C.; PIRES, S. M. 2007. Mirmecofauna (Hymenoptera, Formicidae) em hospitais e postos de saúde no municipio de Bagé, RS. Arquivos do Instituto Biológico 74 (4): 373-377.         [ Links ]

BRAGANQA, M. A. L.; LIMA, J. D. 2010. Composifao, abundancia e índice de infestafao de espécies de formigas em um hospital materno-infantil de Palmas, TO. Neotropical Entomology 39 (1): 124-130.         [ Links ]

BUENO, O. C.; FOWLER, H. G. 1994. Exotic ants and native ant fauna of Brazilian hospitals. pp. 191-198. In: Williams, D. F. (Ed.). Exotic ants: biology, impact and control of introduced species. Westview Press. Boulder. 332 p.         [ Links ]

BUENO, O. C.; CAMPOS-FARINHA, A. E. C. 1998. Formigas urbanas: comportamento das espécies que invadem as cidades brasileiras. Revista Vetores e Pragas. 2: 13-16.         [ Links ]

BUENO, O. C.; CAMPOS-FARINHA, A. E. C. 1999. As formigas domésticas. pp. 135-180. In: Mariconi, F. A. M. (Ed.). Insetos e outros invasores de residencias. Fundafao de Estudos Agrários Luiz de Queiroz. Piracicaba. Brasil. 460 p.         [ Links ] 

CAMPOS-FARINHA, A. E. C.; BUENO, O. C.; CAMPOS, M. C. G.; KATO, L. M. 2002. As formigas urbanas no Brasil: Retrospecto. Biológico 64 (2): 129-133.         [ Links ]

COSTA, S. B. D.; PELLI, A.; CARVALHO, G. P.; OLIVEIRA, A. G.; SILVA, P. R.; TEIXEIRA, M. M.; MARTINS; E.; TERRA, A. P. S.; RESENDE, E. M.; OLIVEIRA, C. C. H. B.; MORAIS, C. A. 2006. Formigas como vetores mecánicos de microorganismos no Hospital Escola da Universidade Federal do Triangulo Mineiro. Revista da Sociedade Brasileira de Medicina Tropical 39 (6): 527-529.         [ Links ]

EICHLER, W. 1990. Health aspects and control of Monomorium pharaonis. pp.671-675. In: Meer, R. K. V; Jafé, K.; Cedeno, A. (Eds.). Applied myrmecology: a world pesperctive. Westview Press. Boulder. 741 p.         [ Links ]

FERNÁNDEZ, F. 2003. Introducción a las hormigas de la región neotropical. Instituto de Investigación de Recursos Biológicos Alexander von Humboldt. Bogotá. Colombia. 424 p.         [ Links ]

FOWLER, H. G.; BUENO, O. C.; SADATSUNE, T.; MONTELLI, A, C. 1993. Ants as potential vectors of pathogens in hospitals in the State of Sao Paulo, Brazil. Insect Science and its Application 14: 367-370.         [ Links ]

GARCIA, F. R. M.; AHLERT, C. C.; FREITAS, B. R.; TRAUTMANN, M. M.; TANCREDO, S. P.; LUTINSKI, J. A. 2011. Ants (Hymenoptera: Formicidae) in five hospitals of Porto Alegre, Rio Grande do Sul State, Brazil. Acta Scientiarum. Health Sciences 33 (2): 203-209.         [ Links ]

GAZETA, G. S.; FREIRE, M. L.; EZEQUIEL, O. S.; MAYHÉ-NUNES, A. J.; FERREIRA, S. V; NOBREGA, N. A. 2007. Artrópodes capturados em ambiente hospitalar do Rio de Janeiro, Brasil . Revista de Patologia Tropical 36 (3): 254-264.         [ Links ]

GOTELLI, N. J.; ENTSMINGER, G. L. 2001. EcoSim: Null models software for ecology. Version 7.0. Acquired Intelligence Inc. & Kesey-Bear. Available in: http://homepages.together.net/~gentsmin/ecosim.htm(Review date: 17 March 2013).         [ Links ]

GOTELLI, N. J.; COLWELL, R. K. 2001. Quantifying biodiversity: procedures and pitfalls in the measurement and comparison of species richness. Ecology Letters 4: 379-391.         [ Links ]

HAMMER, O.; HARPER, D. A. T.; RIAN, P. D. 2001. Past: Palaeonthological statistics software package for education and data analysis. Version. 1.37. Available in: <http://palaeo-electronica.org/2001_1/past/issue1_01.htm>. (Review date: 01.11.2010).         [ Links ]

HOLLDOBLER, B.; WILSON, E. O. 1990. The ants. Harvard University Press. Cambridge. 732 p.         [ Links ]

LISE, F.; GARCIA, F. R. M.; LUTINSKI, J. A. 2006. Association of ants (Hymenoptera: Formicidae) with bacteria in hospitals in the State of Santa Catarina, Brazil. Revista da Sociedade Brasileira de Medicina Tropical 39 (6): 523-526.         [ Links ]

LUTINSKI, J. A.; LUTINSKI, C. J.; LOPES, B. C.; MORAIS, A. B. B. 2014. Estrutura da comunidade de formigas (Hymenoptera: Formicidae) em quatro ambientes com diferentes niveis de perturbafao antrópica. Ecología Austral 24:1-13.         [ Links ]

MELO, A. S.; PEREIRA, R. A. S.; SANTOS, A. J.; SHEPHERD, G. J.; MACHADO, G. 2003. Comparing species richness among assemblages using sample units: why not use extrapolation methods to standardize different sample sizes? Oikos 101: 398410.         [ Links ]

MOREIRA, D. D. O.; MORAIS, V.; VIEIRA-DA-MOTA, O.; CAMPOS-FARINHA, A. E. C.; TONHASCA Jr, A. 2005. Ants as carriers of antibiotic-resistant bacteria in hospitals. Neotropical Entomology 34 (6): 999-1006.         [ Links ]

OLAYA-MASMELA, L. A.; ULLOA, P C.; PAYAN, A. 2005. Ants (Hymenoptera: Formicidae) in hospital centers of Valle del Cauca as vectors of nosocomial pathogens. Revista Colombiana de Entomologia 31 (2): 183-187.         [ Links ]

OLIVEIRA, M. F.; CAMPOS-FARINHA, A. E. C. 2005. Formigas urbanas do municipio de Maringá, PR, e suas implicafoes. Arquivos do Instituto Biológico 72 (1): 33-39.         [ Links ]

PESQUERO, M. A.; ELIAS-FILHO, J.; CARNEIRO, L. C.; FEITOSA, S. B.; OLIVEIRA, M. A. C.; QUINTANA, R. C. 2008. Formigas em ambiente hospitalar e seu potencial como transmissoras de bactérias. Neotropical Entomology 37: 472477.         [ Links ]

PEREIRA, R. S.; UENO, M. 2008. Formigas como veiculadoras de microrganismos em ambiente hospitalar. Revista da Sociedade Brasileira de Medicina Tropical 41: 492-495.         [ Links ]

RODOVALHO, C. M.; SANTOS, A. L.; MARCOLINO; M. T.; BONETTI, A. M.; BRANDEBURGO, M. A. M. 2007. Urban ants and transportation of nosocomial bacteria. Neotropical Entomology 36: 454-458.         [ Links ]

SANTOS, P. F.; FONSECA, A. R; SANCHES, N. M. 2009. Formigas (Hymenoptera: Formicidae) como vetores de bactérias em dois hospitais do municipio de Divinópolis, Estado de Minas Gerais. Revista da Sociedade Brasileira de Medicina Tropical 42 (5): 565-569.         [ Links ]

SILVA, E. J. E.; LOECK, A. E. 2006. Guia de reconhecimento das formigas domiciliares do Rio Grande do Sul. Pelotas: Universidade Federal de Pelotas. 26 p.         [ Links ]

SILVESTRE, R.; BRANDAO, C. R. F.; SILVA, R. R. 2003. Grupos funcionales de hormigas: el caso de los gremios del Cerrado. pp. 159-166. In: Fernández, F. (Ed.). Introducción a las hormigas de la región neotropical. Instituto de Investigación de Recursos Biológicos Alexander Von Humboldt. Bogotá. Colombia. 423 p.         [ Links ]

SOARES, N. S.; ALMEIDA, L, O.; GONQALVES, C. A.; MARCOLINO, M. T.; BONETTI, A. M. 2006. Levantamento da diversidade de formigas (Hymenoptera: Formicidae) na regiao urbana de Uberlandia, MG. Neotropical Entomology 35: 324-328.         [ Links ]

ZARZUELA, M. F. M.; RIBEIRO, M. C. C.; CAMPOS-FARINHA, A. E. C. 2002. Distribuido de formigas urbanas em um hospital da regiao sudeste do Brasil. Arquivos do Instituto Biológico 69 (1): 85-87.         [ Links ]

Received: 10-Jan-2015 ]]> Accepted: 13-Nov-2015

Suggested citation:

LUTINSKI, J. A.; AHLERT, C. C.; FREITAS, B. R.; TRAUTMANN, M. M.; TANCREDO, S. P.; GARCÍA, F. B. M. 2015. Ants (Hymenoptera: Formicidae) in hospitals of southern Brazil. Revista Colombiana de Entomología 41 (2): 235-240. Julio - Diciembre 2015. ISSN 0120-0488.