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Authors
Abstract(s)
As bactérias do género Campylobacter e do grupo Arcobacter sensu lato são bacilos de Gramnegativo, pertencentes à família Campylobacteraceae. Até ao momento, 35 espécies foram
reconhecidas no género Campylobacter, e 31 no grupo Arcobacter sensu lato, sendo que entre
elas, Campylobacter jejuni, Campylobacter coli, Aliarcobacter butzleri, Aliarcobacter
cryaerophilus e Aliarcobacter skirrowii, são as principais espécies associadas a infeções em
humanos e animais. Embora exijam um hospedeiro, as bactérias do género Campylobacter são
comumente isoladas de amostras de águas naturais, como nascentes, rios e lagos. De igual
forma, mais de metade das espécies de Arcobacter sensu lato foram isoladas a partir de
ambientes aquáticos. Esta situação revela-se como uma importante ameaça à saúde pública
devido ao contacto direto do Homem com este tipo de águas. Esta preocupação é acrescida pela
associação de surtos de doenças com o consumo de água contaminada com estas bactérias,
sendo esta uma importante via de transmissão. Assim, o objetivo deste estudo focou-se na
avaliação da distribuição de Campylobacter spp. e Arcobacter sensu lato em diferentes
amostras de água, nomeadamente água de rio, água de afluentes e água de nascente não tratada,
recolhidas no concelho da Covilhã, e avaliação da sua resistência a 7 antibióticos, normalmente
utilizados no tratamento de infeções por estes microrganismos. Pela análise dos resultados, das
150 amostras analisadas por duas metodologias de deteção distintas, PCR e cultura, 56 (37,3 %)
foram positivas para Campylobacter spp. quando utilizada deteção direta por PCR no meio de
enriquecimento, e por isolamento 22 (14,6 %) revelaram a presença deste género; no total 60
amostras foram positivas por ambos os métodos. Em 8 de 22 amostras (36,4%) foi identificado
C. jejuni, em 7 (31,4 %) C. coli, em 4 (18,2 %) C. lari, e 1 (4,5 %) foi positiva para C. upsaliensis,
sendo que para duas amostras não foi possível obter uma identificação a nível de espécie. Em
relação a Arcobacter sensu lato, também alguma variabilidade foi encontrada aquando da
utilização destas duas metodologias, onde 72 de 150 amostras (48 %) foram positivas para o
género quando utilizada deteção direta por PCR no meio de enriquecimento, e através de
cultura foi possível o isolamento de bactérias deste grupo em 89 (59,3%) amostras; no total 99
amostras foram positivas considerando ambos os métodos. Em 74 das 89 amostras (83,1%)
foram identificadas como positivas para A. butzleri, 20 (22,5%) para A. cryaerophilus e 28
amostras encontravam-se contaminadas por outras espécies de Arcobacter. Pela avaliação da
diversidade genética, pela técnica de reação em cadeia da polimerase por consenso intergénico
repetitivo enterobacteriano (ERIC-PCR - do inglês enterobacterial repetitive intergenic
consensus-PCR), foi observada uma grande heterogeneidade genética entre os isolados de
ambos os grupos bacterianos, registando-se 37 perfis genéticos diferentes entre os isolados
provenientes das 22 amostras positivas para Campylobacter spp., e da mesma forma foram
observados 255 perfis únicos de um total de 291 isolados de Arcobacter sensu lato. Quando
avaliado o perfil de suscetibilidade a antibióticos, foram observadas diferenças nos perfis de
resistência entre ambos os grupos bacterianos. Desta forma, para além de resistências pontuais,
observou-se uma baixa multirresistência para o género Campylobacter, em apenas 2 dos 25 isolados avaliados, tendo-se obtido valores superiores para Arcobacter sensu lato, onde de um
total de 238 isolados, 194 mostraram perfil de multirresistência, tendo-se verificado casos em
que a resistência foi transversal a seis dos sete antibióticos testados. Assim, os resultados deste
estudo demonstram uma elevada prevalência de Campylobacter spp e Arcobacter sensu lato,
agravada pela alta resistência a antibióticos encontrada, em amostras de água superficial de
acesso ao homem, apresentando não só alto risco para a população e animais da região, mas
também para uma possível contaminação de alimentos.
The bacteria of the genera Campylobacter and Arcobacter sensu lato group are Gram-negative bacilli, belonging to the Campylobacteraceae family. Until now, 35 species have been recognized for the genus Campylobacter, and 31 species for Arcobacter sensu lato. Amongst the species of both groups, Campylobacter jejuni, Campylobacter coli, Aliarcobacter butzleri, Aliarcobacter cryaerophilus and Aliarcobacter skirrowii are the most frequently associated with infections in humans and animals. Although requiring a host, bacteria of the genus Campylobacter are commonly isolated from samples of natural waters, such as spring waters, rivers and lakes. Likewise, more than half of the Arcobacter sensu lato species have been isolated from aquatic environments. In fact, water is considered a relevant contamination source and an important threat to public health due to their consumption and direct contact with humans. This concern is increased by the association of outbreaks with the consumption of water contaminated with these bacteria, pointing to their consumption as an important route of transmission. Thus, this study focused on assessing the distribution of Campylobacter spp. and Arcobacter sensu lato in different water samples, such as river water, water from affluents and untreated spring water, collected in the municipality of Covilhã, and evaluation of their resistance to seven antibiotics commonly used in the treatment of infections by these microorganisms. Through the analysis of the results, of the 150 samples evaluated by two distinct detection methodologies, PCR and culture, 56 (37.3 %) samples were positive for Campylobacter spp. when using direct detection on the enrichment broth, and 22 (14.6%) were positive by culture; in total, 60 samples were positive by both methods. The distribution by species was as follows: eight of 22 samples (36.4%) were positive for C. jejuni, seven (31.4 %) for C. coli, four (18.2 %) for C. lari, one sample (4.5 %) was positive for C. upsaliensis, and for two of the samples it was not possible to obtain an identification at the species level. Regarding Arcobacter sensu lato, some variability was also found when using these two methodologies, where 72 out of 150 samples (48%) were positive for the genus when using direct PCR detection in the enrichment medium. Through culture it was possible the isolation of bacteria from this group from 89 (59.3%) samples; and in total 99 samples were positive by both methods. Concerning Arcobacter sensu lato, the distribution of the species was as follows: 74 of the 89 samples (83.1%) were positive for A. butzleri, 20 (22.5%) for A. cryaerophilus and 28 samples were contaminated with other species of Arcobacter. Through the evaluation of the genetic diversity by enterobacterial intergenic consensus-PCR polymerase chain reaction technique (ERIC-PCR), a large genetic heterogeneity was observed among isolates of both genera. Among isolates from 22 Campylobacter spp. positive samples by culture, 37 different genetic profiles were found. Similarly, 255 unique profiles of a total of 291 Arcobacter sensu lato isolates were observed. When the antibiotic susceptibility profile was evaluated, divergences between the resistance of both groups were noted. Thus, in addition to pontual resistances, a low multidrug resistance was observed for the genus Campylobacter, only two among the 25 isolates studied. Higher values were obtained for Arcobacter sensu lato, where from a total of 238 isolates, 194 showed a multidrug resistance profile, of which some presented transversal resistance to six of the seven antibiotics tested. In sum, the results of this study demonstrate a high prevalence of both bacterial groups in water samples accessible to humans, worsen by the high resistance found in those samples, presenting not only high risk for the population and animals of the region, but also for possible food contamination.
The bacteria of the genera Campylobacter and Arcobacter sensu lato group are Gram-negative bacilli, belonging to the Campylobacteraceae family. Until now, 35 species have been recognized for the genus Campylobacter, and 31 species for Arcobacter sensu lato. Amongst the species of both groups, Campylobacter jejuni, Campylobacter coli, Aliarcobacter butzleri, Aliarcobacter cryaerophilus and Aliarcobacter skirrowii are the most frequently associated with infections in humans and animals. Although requiring a host, bacteria of the genus Campylobacter are commonly isolated from samples of natural waters, such as spring waters, rivers and lakes. Likewise, more than half of the Arcobacter sensu lato species have been isolated from aquatic environments. In fact, water is considered a relevant contamination source and an important threat to public health due to their consumption and direct contact with humans. This concern is increased by the association of outbreaks with the consumption of water contaminated with these bacteria, pointing to their consumption as an important route of transmission. Thus, this study focused on assessing the distribution of Campylobacter spp. and Arcobacter sensu lato in different water samples, such as river water, water from affluents and untreated spring water, collected in the municipality of Covilhã, and evaluation of their resistance to seven antibiotics commonly used in the treatment of infections by these microorganisms. Through the analysis of the results, of the 150 samples evaluated by two distinct detection methodologies, PCR and culture, 56 (37.3 %) samples were positive for Campylobacter spp. when using direct detection on the enrichment broth, and 22 (14.6%) were positive by culture; in total, 60 samples were positive by both methods. The distribution by species was as follows: eight of 22 samples (36.4%) were positive for C. jejuni, seven (31.4 %) for C. coli, four (18.2 %) for C. lari, one sample (4.5 %) was positive for C. upsaliensis, and for two of the samples it was not possible to obtain an identification at the species level. Regarding Arcobacter sensu lato, some variability was also found when using these two methodologies, where 72 out of 150 samples (48%) were positive for the genus when using direct PCR detection in the enrichment medium. Through culture it was possible the isolation of bacteria from this group from 89 (59.3%) samples; and in total 99 samples were positive by both methods. Concerning Arcobacter sensu lato, the distribution of the species was as follows: 74 of the 89 samples (83.1%) were positive for A. butzleri, 20 (22.5%) for A. cryaerophilus and 28 samples were contaminated with other species of Arcobacter. Through the evaluation of the genetic diversity by enterobacterial intergenic consensus-PCR polymerase chain reaction technique (ERIC-PCR), a large genetic heterogeneity was observed among isolates of both genera. Among isolates from 22 Campylobacter spp. positive samples by culture, 37 different genetic profiles were found. Similarly, 255 unique profiles of a total of 291 Arcobacter sensu lato isolates were observed. When the antibiotic susceptibility profile was evaluated, divergences between the resistance of both groups were noted. Thus, in addition to pontual resistances, a low multidrug resistance was observed for the genus Campylobacter, only two among the 25 isolates studied. Higher values were obtained for Arcobacter sensu lato, where from a total of 238 isolates, 194 showed a multidrug resistance profile, of which some presented transversal resistance to six of the seven antibiotics tested. In sum, the results of this study demonstrate a high prevalence of both bacterial groups in water samples accessible to humans, worsen by the high resistance found in those samples, presenting not only high risk for the population and animals of the region, but also for possible food contamination.
Description
Keywords
Água Ambiental Água de Consumo Arcobacter Sensu Lato Campylobacter Spp Diversidade Genética Resistência A Antimicrobianos