Incidence of Nocardia species in raw milk collected from different localities of Assiut City of Egypt

This study aimed to isolate and enumerate Nocardiae from the examined raw milk samples. 240 random milk samples were collected from cows, buffaloes, sheep and goats from different localities in Assiut cityEgypt. The incidences of 4 4 4 3 Nocardia spp. were 47.8, 43.3, 53.3 and 66.7% with average counts of 3.8 x10 , 4.5x10 , 1.4x10 and 7.6x10 /CFUmL of the examined samples, respectively. Pathogenicity of the isolates was also studied. N. otitidiscavarium and N. brasiliensis caused sudden death of rats while, N. farcinica and N. carnea strains were non pathogenic. Other species caused several lesions. It was concluded from the study that, Nocardia species are existed in retailed and fresh milk of different farm animals. Most of the isolated strains were highly pathogenic to rats. Consequently, preventive measures should be taken to protect consumers from being infected.


Introduction
milk were collected during year 2009 from different localities in Assiut city, Egypt.The samples included Nocardia species are one of the worldwide cow's milk (90), buffalo's milk (90), sheep's milk (30) bacterial infections and has been implicated in the and goat's milk (30).Cow and buffalo's milk samples pathogenesis of pulmonary nocardiosis, brain abscesses, were collected from dairy farms, dairy shops and street enteritis, arthritis, and endocarditis in all infected vendors (30 samples of each).humans, including children and immune suppressed Isolation of Nocardia species: One mL of each patients (Maria Bernadete et al., 2007).Infections due milk sample was aseptically inoculated into Bushnellto Nocardia spp.are generally acquired through Haas broth (Difco) (Schaal, 1972).The inoculated inhalation, trauma and ingestion (Dwight et al., 2004 tubes were incubated at 37 °C for 2-7 days and and Martínez et al., 2008).The seriousness of the examined every 2 days.A loopfull from the incubated disease returns to the fact that clinical diagnosis is broth cultures was streaked onto plates of nocardia difficult due to non-specific manifestations (Saubolle media (Difco) and incubated at 37 °C for 2-7 days and Sussland, 2003) and contamination of soil from (Gordon et al., 1974).the infected patient who plays an important role in Identification of the isolates: Suspected colonies wide spreading of the pathogens (Pisoni et al., 2008).
were identified morphologically and microscopically Economically, the most important host is the (Brown and McNeil, 2003).Biochemical tests and dairy cow.High incidence of bovine mastitis (due to confirmation of species were applied according to nocardia infection) has been reported all over the Cowan and Steel, (1974).world (Pisoni, 2008).Presence of Nocardia spp. in raw Enumeration of Nocardia species (APHA, 1992): milk is not surprising as they are soil-borne aerobic 10 mL of each prepared sample were added to 90 mL actinomycetes (Saubolle and Sussland, 2003), and of sterile saline solution, mixed to make a dilution of may contaminate milk during milking, handling, 1/10, from which ten fold serial dilutions were storage and transportation (Schinger, 1994).The prepared.0.1 mL from each dilution was transferred present work investigated the existence of Nocardia and spread over a dry surface of nocardia agar plates species in different raw milk (cows, buffaloes, sheep (Difco).The plates were incubated at 37 °C for 2-7 and goats) as well as their pathogenicity.
days and the numbers of Nocardia spp./mL were cultures contain approximately 10 CFU/mL.N. otitidis-cavarium, N. transvalensis, and N. vaccinii The intraperitoneal inoculation of rats: 27 rats were also virulent causing similar lesions.N. were I/P inoculated with nine different Nocardia otitidiscavarium and N. brasiliensis caused sudden species (3 rats for each strain).Each rat was injected death.On the other hand, N. farcinica and N. carnea I/P with one mL of the broth culture.Another 3 rats were non pathogenic.Histopathological studies were kept as a control (Pier et al., 1961).Two weeks showed inflammatory edema between the villi of the later, all animals that survived were sacrificed and intestine and increase of the goblet cells (Fig. 2A).subjected to PM inspection and histopathology Liver showed degeneration of the hepatic cells according to Bancroft et al., (1996).The especially in the portal area (Fig. 2B and C).Lung representative lesions were cultured for reisolation of showed degeneration of the bronchial epithelium, the inoculated Nocardia species.
congestion of the bronchial blood vessels and thickening in the interalveolar septa with inflammatory cells (Fig.
Discussion 19 (63.3%) out of 30 cow's milk samples from dairy farms, were found to be contaminated with Nocardia In the current study the incidence of Nocardia 4 spp.with average count of 1.3x10 CFU/mL.Lower spp. in milk samples was considered higher than other percentages (46.7, 33.3 %) were found in milk samples previous studies (Abdel-Fattah, 1996 and Seddek, from street vendors and dairy shops with average 2001).This higher incidence may be attributed to the 3 4 counts of 7.4x10 and 2.6x10 CFU/mL, respectively.fact that they are wide spread in nature.They may be In buffalo's milk samples, the highest incidence (60%) introduced into the udder by insertion of cannula, was obtained from milk samples from dairy farms.contaminated preparations, drug mixture and tips of However, the incidences in buffalo's milk samples injectors (Seddek, 2001).The extensive use of from dairy shops and street vendors were 36.7% and antibiotics in the treatment of mastitis increased the 4 3 incidence of Nocardia infection (Pisoni et al. 2008).33.3% with average counts of 1.2x10 and 5.9x10 Furthermore, the lack of hygienic measures and poorly CFU /mL, respectively.Nocardia spp.could be sanitized dairy farm equipments constitute the major isolated from sheep and goat's milk samples in  sources of contamination of different types of milk.and equipment used in milk production was essential.
The highest incidence of Nocardia spp. in goat's milk The extensive use of antibiotics in the treatment of associated with poor hygienic nomadic rearing mastitis should be avoided as this may increase the Nocardial conditions in housing and in the milking parlous incidence of infection.Moreover, persons (Contreras et al., 2002).Some environmental factors who handle milk should be periodically examined to Nocardia facilitate multiplication of these organisms in milk prevent transmission of spp.by food such as hot and wet weathers.Contamination of soil handlers into the food chain.from the infected patient plays an important role in

milk samples Dairy farms Dairy shops Street vendors Dairy farms Dairy shops Street vendors Sheep's milk Goat'smilk
Incidence of Nocardia species in raw milk collected from Different localities of Assiut City of Egypt