693Revista MVZ CórdobaRev. MVZ Córdoba0122-02681909-0544Universidad de CórdobaColombiarevistamvz@gmail.com69360322020https://doi.org/10.21897/rmvz.1232OriginalIncidence of Escherichia coli 0157:H7 in feces of lactating ruminants with diarrheal syndromeIncidencia
de Escherichia coli O157:H7 en heces de rumiantes
lactantes con síndrome diarreicohttp://orcid.org/0000-0003-4974-6455Lara-DuranJosé Alfredofredy_ingeniebro@hotmail.comhttp://orcid.org/0000-0002-3276-7519Silva-VegaMónicamsilva58@hotmail.comhttp://orcid.org/0000-0001-9298-0840Bañuelos-ValenzuelaRómuloapozolero@hotmail.comhttp://orcid.org/0000-0002-6640-2753Delgadillo-RuizLucíadelgadillolucia@gmail.comhttp://orcid.org/0000-0003-1784-7550Delgadillo-RuizOliviadelgadilloruiz@gmail.comUniversidad Autónoma de Zacatecas, Unidad Académica de Medicina
Veterinaria y Zootecnia, Km 31.5 de la carretera panamericana tramo
Zacatecas-Fresnillo, Enrique Estrada, Zacatecas, México.Universidad Autónoma de ZacatecasMéxicoUniversidad Autónoma de Zacatecas, Unidad Académica de Medicina
Veterinaria y Zootecnia, Km 31.5 de la carretera panamericana tramo
Zacatecas-Fresnillo, Enrique Estrada, Zacatecas, México.Universidad Autónoma de ZacatecasMéxicoUniversidad Autónoma de Zacatecas, Unidad Académica de Medicina
Veterinaria y Zootecnia, Km 31.5 de la carretera panamericana tramo
Zacatecas-Fresnillo, Enrique Estrada, Zacatecas, MéxicoUniversidad Autónoma de ZacatecasMéxicoUniversidad Autónoma de Zacatecas, Unidad Académica de Ciencias Biológicas,
Avenida preparatoria s/n colonia Hidráulica, Zacatecas, Zacatecas, México.Universidad Autónoma de ZacatecasMéxicoCONACYT-Consorcio CENTROMET, Camino a Los Olvera #44, Corregidora,
Querétaro, México.CONACYT-Consorcio CENTROMETMéxicoSeptember-December2019243733973451009201810062019180920192019Revista MVZ Córdobahttps://creativecommons.org/licenses/by-nc-sa/4.0/Esta obra está bajo una Licencia Creative Commons Atribución-NoComercial-CompartirIgual 4.0 Internacional.Abstract
Objective. To identify Escherichia coli 0157:H7 present in diarrheal feces of lactating ruminants with diarrheal syndrome and safety of colostrum intake. Materials and methods. A feces sampling of 316 ruminants was carried out during the period of August 2015 to March 2016 in the municipalities of Río Grande, General Enrique Estrada, Morelos and Calera de Victor Rosales of the state of Zacatecas, obtained from 67 cattle, 183 sheep and 66 goats. Results. The following were identified in CHROMagarTM chromogenic medium: 260 coliforms, 78 Escherichia coli 0157:H7, 16 Proteus spp. and 25 colonies of unidentified bacteria, finding an incidence of Escherichia coli 0157:H7 of 22.03% in the four municipalities. Conclusions. Escherichia coli 0157:H7 is the second bacteria found in ruminant feces with an incidence of 22%, which is a mortality risk factor in lactating ruminants (less than 21 days old), causing economic loss and health risk for the population of the state of Zacatecas.
Resumen
Objetivo. Identificar Escherichia coli O157:H7 presente en heces diarreicas de rumiantes lactantes con síndrome diarreico y seguridad de ingesta de calostro. Materiales y métodos. Se realizó un muestreo de 316 rumiantes durante el período de agosto 2015 a marzo 2016 en los municipios de Río Grande, General Enrique Estrada, Morelos y Calera de Víctor Rosales del estado de Zacatecas, 67 de bovinos, 183 de ovinos y 66 de caprinos. Resultados. Se identificaron en medio cromogénico CHROMagarTM: 260 coliformes, 78 Escherichia coli O157:H7, 16 Proteus spp., y 25 colonias de bacterias sin identificar con este medio, encontrándose una incidencia de Escherichia coli O157:H7 de 22.03% en los cuatro municipios. Conclusiones.Escherichia coli O157:H7 es la segunda bacteria encontrada en heces de rumiantes con un 22% de incidencia, la cual es un factor de riesgo de muerte en rumiantes lactantes (menos de 21 días de nacidos) causando pérdidas económicas y riesgo para la salud de la población del estado de Zacatecas.
KeywordsBacteria chromogenic medium sheepPalabras claveBacterias medio cromogénico ovinos How to cite (Vancouver)Lara-Duran
JA, Silva-Vega M, Bañuelos-Valenzuela R, Delgadillo-Ruiz L, Delgadillo-Ruiz O. Incidence of Escherichia coli 0157:H7 in feces
of lactating ruminants with diarrheal syndrome. Rev MVZ Cordoba. 2019; 24(3):7339-7345.
DOI: https://doi.org/10.21897/rmvz.1232
<bold>INTRODUCTION</bold>
The economic repercussion resulting from digestive diseases in ruminants in Mexico is serious and frequent. The pathological symptoms presented by the ruminants under this type of stress are as follows: low feed consumption, presence of diarrheas (or dysentery), ruminal acidosis, laminitis, limp, delay in corporal development of lambs, kids and calves (1). This means an unforeseen added cost for the producer, along with expenses in veterinary treatments (2).
In intensive production systems, the mortality index of lambs due to digestive diseases prior to weaning tends to be less than 10%, whereas in extensive systems the losses can be as high as 53% of the lambs born (3). However, various reports mention that infectious processes and nutritional and metabolic disorders represent the principal cause of neonatal mortality (4). In fact, between 15 and 20% of the neonatal losses can be attributed to digestive diseases, and consequently, the rest (around 80%) are the result of environmental or management factors (3).
The Centers for Disease Control (CDC) of the Department of Health and Human Services of the United States mention that Escherichia coli is a type of bacteria that normally lives in the intestines of humans and animals. For the most part they are inoffensive and in fact are part of a healthy intestinal tract. However, some serotypes are pathogens, causing diarrheas or diseases outside of the intestinal tract (5).
Escherichia coli is classified into six serotypes that are associated with diarrhea; among these is enterohemorrhagic Escherichia coli (EHEC), which causes hemorrhagic colitis (HC) and is identified through the production of Shiga toxins (Stxs). Shiga toxin-producing Escherichia coli (STEC) is a group of zoonotic pathogens, and Escherichia coli 0157:H7 is the serotype associated with hemorrhagic colitis and hemolytic uremic syndrome (HUS), principally in the United States.
Laven et al (7) demonstrated that the presence of Escherichia coli in ruminants was higher in the colon than in the rumen, associating the presence of Escherichia coli to the ingestion phase and not to the intestinal wall of the rumen. Studies have demonstrated that the terminal part of the colon is the principal development site of the colonization of Escherichia coli 0157:H7 and that the lymphoid tissue located in the recto-anal junction is the colonization site in cattle (8). Therefore, this colonization is considered a “super-propagator” which causes severe infections with epidemiological manifestations characterized by hemorrhagic diarrheas, colitis and hemolytic uremic syndrome (9).
Adequate isolation and identification methods are crucial for the diagnosis of Escherichia coli 0157:H7. Before confirming its presence in a sample, it is necessary to isolate and identify it in selective and differential culture media. The media used conventionally for the isolation of Escherichia coli 0157:H7 include Sorbitol MacConkey Agar (SMAC), CefiximeTellurite Sorbitol MacConkey Agar (CT-SMAC), CHROMagarTM 0157 (CHROMagar), Tellurite CHROMagarTM 0157 (T-CHROMagar) and Vancomycin Cefixime Cefsoludin CHROMagarTM 0157 (VCCCHROMagar) (6,10).
The chromogenic chemical substrates patented for the identification of microbial colonies led to the development of a wide range of media for the detection of pathogens. The medium CHROMagarTM 0157 selectively promotes the growth of Escherichia coli 0157:H7 and the difference from Escherichia coli no. 0157, due to a chromogenic substrate of β -galactosidase and a change in the pH (6). This medium is used for the detection of Escherichia coli 0157:H7 in alimentary as well as environmental samples, but could be more selective with the addition of potassium tellurite, or with vancomycin, cefixime and cefsoludin (11).
Therefore, the objective of the present study was to identify Escherichia coli 0157:H7 in diarrheic feces of lactating ruminants younger than 21 days through the use of agar CHROMagarTM, which will permit producers to make decisions about which treatments to employ in order to avoid the incidence of this pathogen and reduce neonatal mortality.
<bold>MATERIALS AND
METHODS</bold>
Samples. 316 swabbed rectal samples from 183
sheep, 66 of goats and 67 of cattle under 21 days of
age were obtained, and with the security of having ingested colostrum, with
presence of diarrheic syndrome. The samples were collected rectally with a
sterile cotton swab, and were labeled and transported in Stuar ® medium. The sampling was carried out
during the period of August 2015 to March 2016 in four municipalities of the
state of Zacatecas: in Calera de Victor Rosales, the localities El Bordo, Noria de Agostadero, El Duraznillo, El Vergel and El Porvenir: in
Morelos the localities of Hacienda Nueva, Noria de
Gringos, Las Pilas and El Palmar: in General Enrique
Estrada, Los Ángeles, Puentecillos and
San Sebastián, and in Río Grande the localities El Carrizal, Los Ramírez, San José de Ranchitos and Tierra Blanca (Figure 1).
(Coordinates: El Bordo 102°49’20”O 22°57’02”N, San
José de Ranchitos 102°57’35”O 23°40’0”N, El Carrizal 103°01’08”O 23°38’25”N, El Duraznito
102°38’26”O 23°01’29”N, El Palmar 102°39’58”O 22°53’24”N, El Porvenir 102°40’00”O 22°56’42”N, El Vergel
102°41’01”O 22°59’58”N, General Enrique Estrada 102°44’29”O 22°59’40”N,
Hacienda Nueva 102°36’21”O 22°49’30”N, Las Pilas
102°36’46”O 22°50’24”N, Los Ramírez 103°01’52”O 23°50’49N”, Los Ángeles
102°43’22”O 22°58’43”N, Noria De Agostadero
102°46’59”O 22°53’14”N, Noria de los Gringos
102°43’04”O 22°50’53”N, Puentecillos 102°45’03”O
23°02’47”N, San Sebastián 102°47’54”O 23°03’37”N,
Tierra Blanca 103°04’36”O 23°49’38”N).
Geographic location of
the localities sampled in the four municipalities of the state of Zacatecas.
Figure
1 Geographic location of
the localities sampled in the four municipalities of the state of Zacatecas.
Gram negative bacterial culture. The cultures were made in duplicate. Each sample was sown in Petri jars with MacConkey agar (SMAC), and incubated in a bacteriological oven at 37 °C for 48 hours (12). The creamy pink colonies were considered positive and were individually isolated for their later re-sowing.
Identification of bacteria in chromogenic medium CHROMagarTM. After the bacteria were isolated in MacConkey agar, a colony was taken for the identification of the serotype of Escherichia coli 0157:H7 or its non-mobile variant 0157:H (serotype VTEC), which is more common in public health. The re-sowing was made by plate striation in chromogenic medium CHROMagarTM and was incubated at 37 °C during 24 hours (13) (Table 1)..
The colonies of Escherichia coli 0157:H7 grow in CHROMagarTM 0157 and produce a mauve pink color due to chromogenic substrates in the medium, thus permitting the presumptive identification of the primary isolation plate and the differentiation from other organisms (13) (Table 1).
Characteristics
of the colonies using the CHROMagar<sup>TM</sup>
chromogenic medium.
Table
1 Characteristics
of the colonies using the CHROMagarTM
chromogenic medium.
Microorganism
Aspect of the colony
Observation in culture
E. coli
O157:H7
mauve pink
Coliformes
metallic blue
Proteus
colorless to gray
Statistical
analysis.
The experimental data were analyzed first with descriptive statistics, and
afterwards using a classification table or contingency table. The Chi-squared
statistical analysis was used, which is a statistic that makes it possible to
determine the degree of independence among the variables. The assumption of
this test is as follows: Ho: The prevalence of the bacteria is independent from
the type of ruminant the carrier may be; Ha: The prevalence of the bacteria is
dependent on the type of ruminant carrier. The most important index of this
test is the value p. In general, when the value p is less than 0.05, Ho is
rejected and it is concluded that the bacteria are not independent. Al of the
statistical process was carried out with SPSS 25.0 for Microsoft Windows.
<bold>RESULTS</bold>
The determination of Escherichia coli
0157:H7 was made using chromogenic medium CHROMagarTM
differentiating the bacterial colonies by color; Escherichia coli
0157:H7 presented mauve pink coloration, Proteus ssp. are from colorless
to gray and the coliforms present metallic blue colored colonies, as can be
seen in Figure 2.
Development
of bacteria in CHROMagar<sup>TM</sup>. A) Coliforms, B) <italic>E. coli</italic>
O157: H7 and C) <italic>Proteus</italic>
spp.
Figure 2 Development
of bacteria in CHROMagarTM. A) Coliforms, B) E. coli
O157: H7 and C) Proteus
spp.
Some samples presented development of two or more colonies with distinct morphology and coloration, thus the total number of the bacterial colonies identified was 354, and in 25 cases there was no development in 24 hours, despite the fact that development was found in MacConkey agar and colonies with descriptive morphology for Escherichia coli there was no development in CHROMagarTM.
260 coliforms were identified, along with 78 Escherichia
coli 0157:H7 and 16 Proteus spp., in all of the ruminants sampled,
of which 183 were sheep, where it was found that in 46 sheep there was presence
of Escherichia coli 0157:H7, in goats it was found in 7 of 66 and in
cattle, 25 of 67 as is shown in Table 2. Furthermore, using the chi-squared
test it is confirmed that the prevalence of the bacteria (coliforms, Escherichia
coli 0157:H7 and Proteus spp.) depends on the type of ruminant
(sheep, cattle and goat) which is the carrier of the bacteria (Table 3).
Number of bacteria
obtained from sowing in CHROMagar<sup>TM</sup>.
Table
2 Number of bacteria
obtained from sowing in CHROMagarTM.
Source
# Animals
Coliforms
E. coli
O157:H7
Proteus spp.
N.D.
#
Bacteria
Sheep
183
153
46
8
14
221
Goats
66
61
7
4
4
82
Bovine
67
46
25
4
7
76
Total
316
260
78
16
25
379
N.D.:
Not determined.
Contingency table:
type of bacteria vs ruminant type.
Table
3 Contingency table:
type of bacteria vs ruminant type.
Type of ruminant
Total
Sheep
Bovine
Goats
Prevalence of the bacteria
E. coli
O157:H7
46
25
7
78
20.8%
30.5%
9.2%
20.6%
Coliforms
153
46
61
260
69.2%
56.1%
80.3%
68.6%
Proteus
8
4
4
16
3.6%
4.9%
5.3%
4.2%
N.D.
14
7
4
25
6.3%
8.5%
5.3%
6.6%
Total
221
82
76
379
100.0%
100.0%
100.0%
100.0%
Ho:
The prevalence of bacteria is independent of the type of ruminant that is the
carrier; Ha: The prevalence of bacteria is dependent on the type
of ruminant that is the carrier. Chi-square value of Pearson=13.243. gl=6;
p=0.039. As the value of p≤0.05 is rejected Ho. N.D.: No Determinados.
The distribution of bacteria found according to
their geographic location correspond to the following: 18 Escherichia coli
0157:H7, 60 coliforms and 7 Proteus ssp., in the municipality of Calera de
Victor Rosales; 40 Escherichia coli 0157:H7, 11 coliforms and 9 Proteus
ssp., in localities of Morelos, 24 Escherichia coli 0157:H7, 41 coliforms and 1
Proteus ssp., in localities General Enrique Estrada and 16 Escherichia
coli 0157:H7, 99 coliforms and 4 Proteus ssp., in localities of the
municipality of Río Grande (Table 4).
Bacteria determined by location and type of
ruminant.
Table 4 Bacteria determined by location and type of
ruminant.
Municipalities
Localities
E. coli O157:H7
Coliformes
Proteus
Sheep
Bovine
Goats
Sheep
Bovine
Goats
Sheep
Bovine
Goats
Calera de Víctor Rosales
El bordo
1
0
0
9
1
2
1
0
0
Noria de agostadero
1
0
0
12
2
2
0
0
1
El duraznillo
5
4
1
5
1
1
1
0
0
El porvenir
5
0
0
11
2
3
0
1
1
El vergel
1
0
0
6
2
1
1
0
1
Morelos
Hacienda Nueva
2
0
0
3
3
3
0
1
0
Noria de gringos
3
0
2
20
5
1
0
1
0
Las pilas
2
1
0
4
1
4
1
0
0
El palmar
2
8
0
13
2
1
1
0
0
General Enrique Estrada
General Enrique Estrada
3
0
0
3
2
3
0
0
0
Los Ángeles
5
0
0
2
1
3
0
0
0
Puentecillos
8
0
0
5
0
6
1
0
0
San Sebastián
4
3
1
8
5
3
0
0
0
Río Grande
El carrizal
0
0
0
8
4
6
1
0
0
Los Ramírez
4
0
3
9
3
7
1
0
0
San José de Ranchitos
0
5
0
16
7
7
0
1
1
Tierra blanca
0
4
0
19
5
8
0
0
0
Total:
46
25
7
153
46
61
8
4
4
The highest incidence of
bacteria were the coliforms with 73.45% in the four municipalities,
followed by Escherichia coli 0157:H7 with 22.03% and of Proteus
with 4.52% (Table 5). With these results, the producers of the region are able
to make the best decision of prevention treatments to reduce the incidence of
this pathogen and thus reduce mortality in lactating ruminants.
Percentage
of bacteria incidence by municipality and type of animal.
Table
5 Percentage
of bacteria incidence by municipality and type of animal.
Municipalities
E. coli O157:H7
Coliformes
Proteus
Sheep
Bovine
Goats
Sheep
Bovine
Goats
Sheep
Bovine
Goats
Calera de Víctor Rosales
3.67
1.13
0.28
12.15
2.26
2.54
0.85
0.28
0.85
Morelos
2.54
2.54
0.56
11.30
3.11
2.54
0.56
0.56
0.00
General Enrique Estrada
5.65
0.85
0.28
5.08
2.26
4.24
0.28
0.00
0.00
Río Grande
1.13
2.54
0.85
14.69
5.37
7.91
0.56
0.28
0.28
Incidence %
22.03%
73.45%
4.52%
<bold>DISCUSSION</bold>
The presence of Escherichia coli 0157:H7 in cattle should be taken into consideration as a possible problem of public health, given that this bacteria strain is present in feces and is a source of infection for humans. In the finishing process of the animal, refrigeration of the carcass and also in milking, contamination of the meat and milk may occur (14).
It has been reported that the presence of Escherichia coli 0157:H7 in cattle feces seems to be influenced by the age of the animal (15). For example, calves under eight weeks of age (56 days) and heifers excrete more of the Escherichia coli strain than adult cattle (16).
Escherichia coli 0157:H7 has become an important problem for human health, principally in the United States (6); Olvera et al (17) have stated that cattle are the primary reservoir of the bacteria Escherichia coli 0157:H7, which causes hemolytic uremic syndrome in humans. In fact, the carcasses from feedlot systems present the highest incidence of verotoxigenic Escherichia coli associated with hemolytic uremic syndrome, with respect to the grazing system where vaccination reduced the contamination of these bacteria in beef by 54.1%.
To diagnose this pathogen, adequate isolation and identification methods are crucial. There is little information available on its prevalence in cow/calf management. However, in Louisiana, U.S., an 8% prevalence of this pathogen has been reported, without significant differences among fecal matter, water (from water troughs and ponds) and surface smears (of water troughs and hay bunk) as sources of contamination (6).
In the investigation conducted by Fox et al (18), a general prevalence of 62% was found, higher than what was obtained in the present study (22.03%). The prevalence of Escherichia coli 0157:H7 in cattle is variable among each individual and each herd. In stabled cattle, it can be found in a range of 10 to 28%, but it can be higher, as much as 80% in the summer months (19). Cattle are the most affected, followed by sheep (20), which indicates there is no host selection for Escherichia coli 0157:H7.
With the use of CHROMagarTM it has been possible to rapidly determine the incidence with an identification sensitivity of 98% and a specificity of 100% (13), being superior to MacConkey sorbitol agar, which despite having the same sensitivity, its specificity decreases to 85% and has a precision of 86%. This medium was initially used only in the food industry for the rapid release of pathogen free foods, but it has been tested for clinical sample analyses and has been used in various studies (6, 14, 21, 22). However, for precision of the method, investigation should be continued, focusing on the characterization based on the sequence of nucleic acids through PCR procedures (polymerase chain reaction) that point to genes of the shiga toxin (stx1 and stx2), given that BBL CHROMagar 0157 does not differentiate between the toxin producing and non-toxin producing strains of Escherichia coli 0157:H7 (13).
In conclusion, the coliform bacteria had the highest presence in the samples analyzed. However, they are not considered to be the causal agent of diarrhea. The presence of Escherichia coli 0157:H7 was the second bacteria with highest percentage in the fecal samples analyzed (22.03% incidence), which does not depend on the species of the ruminant, but it represents a mortality risk factor in lactating ruminants (under 21 days of age) causing economic losses and health risk for the population of the state of Zacatecas.
Conflict of interests.
The authors declare no conflict of interest with publication of this manuscript.
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