Representative Salmonella serovars isolated from poultry and poultry environments in Saudi Arabia.

The authors describe the source and prevalence of pathogenic Salmonella serovars among poultry farms in Saudi Arabia. A total of 1,052 (4%) Salmonella isolates were recovered from 25,759 samples of poultry (broilers, layers, broiler breeders and layer breeders) and poultry environments (box liner, litter, drag swab, droppings, mice and feed) were examined bacteriologically between 1988 and 1997 at the Poultry Disease Laboratory at the National Agriculture and Water Research Center in Riyadh. Eleven Salmonella serogroups representing 38 different Salmonella serovars were identified by means of antigenic analysis. The majority of the 276 isolates (26.2%) of Salmonella typed, were recovered from liver, heart and intestines of the broilers and layers. The most prominent Salmonella serogroups isolated were as follows: serogroup C1 (392 isolates, 37.26%), B (289 isolates, 27.47%) and D1 (269 isolates, 25.69%). However, untypable and multiple serogroups were also encountered, the most frequent isolates serotyped belonged to groups C1 (97 isolates, 24.7%), D1 (86 isolates, 31.9%), and B (71 isolates, 24.6%). Salmonella Enteritidis (85 isolates, 98.8%), Salmonella Virchow (48 isolates, 57.8%), Salmonella Paratyphi B var. Java (41 isolates, 57.7%) and Salmonella Infantis (30 isolates, 20.6%) were distributed the most widely as all were encountered in poultry and in poultry environments. S. Enteritidis phage type 4 (30 isolates, 35.3%), was the phage type most frequently detected among group D1 phage types, while 39 (45.8%) of the isolates of S. Enteritidis could not be phage typed.

Bacterial identity and characteristics in healthy and unhealthy respiratory tracts of sheep and calves.

The aim of this study was to compare different bacteriological aspects of the respiratory systems of healthy (H) versus unhealthy (UH) animals with respiratory signs. The prevalence of different bacterial species was determined in the upper and lower respiratory tract of H and UH Najdi sheep, Somali sheep and Holstein calves. The characteristics of Pasteurella spp. isolates, and the biotype of Pasteurella haemolytica were identified in H and UH animals, Eighteen out of 28 (64.3%) of the identified bacterial species in the upper respiratory tract were more prevalent in the nasal cavities of UH Najdi and Somali sheep and Holstein calves with respiratory signs than in apparently healthy animals; four of the most prevalent bacteria in the upper respiratory system of UH sheep were Moraxella spp., Pseudomonas pseudomallei, Erysipelothrix spp., Pasteurella multocida, while three of the most prevalent bacteria in UH calves were Pasteurella haemolytica, Actinomyces spp., and Pseudomonas aeruginosa. The prevalence of six different bacterial species was greater in the lungs of UH animals, namely Actinomyces pyogenes, Erysipelothrix spp., P. haemolytica, Pasteurella ureae, Staphylococcus aureus, and Staphylococcus epidermidis, which could be risk factors in the complexity of the prevalent respiratory diseases of the animals surveyed. Of the biochemical, cytological and colonial characteristics studied in the identified P. haemolytica and P. multocida, two characters were significantly different (p < 0.05) in organisms isolated from UH as compared to those from H animals. These were the higher loss of haemolytic power by the strains of P. haemolytica and the decreased fermentation of trehalose by all the strains of P. multocida recovered from healthy animals. The only biotype of P. haemolytica isolated from H animals was biotype A, while both biotypes A (88.0% of the isolates) and T (12.0% of the isolates) were recovered from UH animals.

Use of live and inactivated Salmonella enteritidis phage type 4 vaccines to immunise laying hens against experimental infection.

Four groups of Dekalb Delta commercial layer hens (8 hens per group) were reared individually in cages in an isolation unit. At the age of 8 weeks, groups 1 and 2 were vaccinated with 9R Salmonella gallinarum live (9R live) vaccine. At the age of 18 weeks, group 1 was re-vaccinated with 9R live S. enteritidis vaccine, while groups 2 and 3 were vaccinated with S. enteritidis bacterin. At the age of 22 weeks, groups 2 and 3 were re-vaccinated with S. enteritidis bacterin. Group 4 was not vaccinated and was kept as a control group. At 24, 27 and 30 weeks of age, the four groups were challenged using various concentrations of S. enteritidis phage type 4 and various routes of inoculation. Eggs, cloacal swabs and blood were collected weekly for bacteriological and serological examination. Isolation of the challenge organism from the eggshells and egg contents of the vaccinated groups was significantly lower than with the control group. There was no correlation between humoral antibodies and the shedding of the challenge organism in eggs or cloacal swabs. A combined vaccination programme of 9R live S. enteritidis vaccine and S. enteritidis bacterin provided better protection to laying hens than either vaccine administered alone. Vaccination should never be performed alone but in conjunction with other measures related to veterinary hygiene and good management.

O-serotypes of Pseudomonas aeruginosa from animal and inanimate sources in Saudi Arabia.

A total of 1012 samples were examined for Pseudomonas aeruginosa and 257 (25.4%) were positive. The incidence of Ps. aeruginosa in samples collected from animal sources (N = 730) was significantly higher (28.7%) than that in 282 samples of inanimate sources (16.7%). The percentage of samples infected with these organisms was lowest in poultry feed (2.8%) and highest in sewage effluent (57.1%). Nine serotypes were defined from all sources. P5 was the common predominant individual O type in infected chicken navels and in the nasal cavities of Najdi sheep (a Saudi Arabian sheep breed), while P3 and P6 were predominate in the nasal cavities of Somali sheep (a breed imported from Somalia). No Ps. aeruginosa serotype was predominant in sheep faeces. In inanimate sources, P4 was predominant in water and sewage effluent. The isolate from the animal feed was untypeable. In using the slide agglutination technique for serotyping, most of the unusual agglutination reaction types of Ps. aeruginosa (70%) were of strains isolated from Somali sheep.

Mastitis in Camelus dromedarius in Saudi Arabia.

The correlation between camels' milk samples collected from abnormal inflamed udders and samples positive in the California Mastitis Test (CMT) was +0.803 (P less than 0.01). The bacterial count ranges of milk samples differed significantly (P less than 0.05) for those with a negative CMT and those with a positive CMT. Infection with many but not all bacterial species was associated with positive CMT results. The highest percentage of camel milk samples was included in the bacterial count range of 3.0 x 10(2) to 3.0 x 10(3) cfu/ml rather than in the greater than 3.0 x 10(3) cfu/ml range for most of the bacterial species. The most predominant bacterial isolates were Micrococcus spp., Staphylococcus aureus, Streptococcus spp. and Corynebacterium spp. followed by eight other flora. Chloramphenicol was the most effective antimicrobial agent of six tested against 118 bacterial isolates. Preliminary observations are made on chemotherapy of mastitis cases in camels.

Use of epidemiologic markers to identify the source of Escherichia coli infections in poultry.

During an epidemiologic study of poultry colisepticemia on 2 Saudi Arabian poultry broiler farms, Escherichia coli was isolated from 101 (40.4%) of the 250 specimens examined. The antigenic structure and the drug resistance pattern of 65.4% of the E coli isolates from different sources were used as epidemiologic markers to trace the source of the infection. The predominant E coli serotypes involved in infections of 2 poultry broiler progeny farms were 033:H4 (51.8%) and 078:H- (19.6%) that had the following respective drug resistance patterns: furazolidone-streptomycin-sulfathiazole and streptomycin-sulfathiazole-tetracycline. Escherichia coli strains with typical epidemiologic markers were isolated from various sources on a broiler breeding farm, but not from well waters of the infected progeny farm. Three other E coli serotypes (045:H10[14.3%], 0119:H27[1.8%], and 0145:H25[1.8%]) were involved in poultry infection, but to a lesser extent. These 3 serotypes were multiply resistant against 5 to 6 of the antimicrobials evaluated.

Production of H2S by Escherichia coli isolated from poultry: an unusual character useful for epidemiology of colisepticemia.

Eleven isolates of H2S-producing Escherichia coli were recovered from necropsy materials of chickens with symptoms and lesions of colisepticemia on Saudi Arabian broiler farms. Results of 19 out of 20 biochemical reactions studied were typical for E. coli. Hydrogen sulfide production by the E. coli isolates was used as an epidemiological marker to pinpoint a breeding farm as the probable source of these strains, which were then transferred to progeny farms, where colisepticemia occurred. This finding was confirmed by the presence of the same antigenic structure (O78:H-) and by the same drug-resistance pattern (a multiple resistance to streptomycin, sulfathiazole, and tetracycline) in the isolates.

Reduction of bacterial infections in newly hatched chicks by the use of antimicrobial dips: preliminary approaches.

Bacteriological examination of hatchery waste eggs, identification of the isolated bacteria, and susceptibility testing against seven antimicrobial agents were used in an attempt to establish a rational basis for reducing bacterial infections in newly hatched chicks. Chloramphenicol at 1000 ppm was selected as the antibiotic for preliminary dipping trials and 0.45% iodophore (Wescodyne) was added for later trials. The control treatment consisted of formaldehyde fumigation. The following conclusions can be drawn: Hatchery waste eggs are highly contaminated (69.1%) and enterobacteriaceae predominate (26.6%). Chloramphenicol is the most effective antimicrobial tested. Dip treatments with either chloramphenicol alone or chloramphenicol plus Wescodyne result in a reduced percentage of abnormal navels (8.4% and 10.4%), as compared with 21.9% for the control treatment. Hatchability of either group of dipped eggs is reduced in comparison with fumigated eggs. Dip treatment with chloramphenicol plus Wescodyne significantly reduces the anal carrier rates for Escherichia coli, Pseudomonas aeruginosa, Salmonella spp., and Staphylococcus aureus. This treatment reduces the incidence of bacterial infection in abnormal navels to zero.

Effect of management changes on hatchability and bacterial infections on a Saudi Arabian poultry breeding farm.

A new management programme for improvement of hatchability and reduction of transmission of bacterial potential pathogens from breeders to hatchery products was applied on a Saudi Arabian poultry farm. The technical changes included better nest engineering, improved cleaning of hatching eggs and better criteria for selecting eggs for incubation. The new nests led to a change in laying behaviour with 86.6% of eggs layed in nests which was significantly higher than was achieved previously. Bacterial penetration in dirty floor eggs was significantly higher than in clean nest eggs. The average hatchability was significantly higher for the flock under the new management than for the same age flock under the old management. The new management reduced transmission of paratyphoid organisms and Escherichia coli from infected breeders to their hatchery products. The old and new managements differed in the percentage of products infected with Salmonella.

A non-motile Salmonella mutant (6, 7:-:-) and two serological variants encountered in Saudi Arabia.

A non-motile mutant of Salmonella group C1 and two serological variants were isolated during the performance of a national Salmonella surveillance program in Saudi Arabia. Most of the biochemical reactions of the strains conformed to those of the genus Salmonella except for some atypical reactions. The three strains exhibited different susceptibility patterns to 21 antimicrobial agents. The serological analysis revealed the following antigenic structures: 1, 4, 12, 27:b: - Salmonella sofia var. monophasic; 1, 42:z4, z23: - Salmonella gera var. monophasic and a Salmonella strain reported as a non-motile strain of group C1 by the World Health Organization International Collaborating Center for Reference and Research on Salmonella.

Occurrence of salmonellae in animal feed ingredients in Saudi Arabia.

Of 346 samples of animal feed ingredients (144 complete feed, 88 feed concentrate, 42 calcium carbonate, 30 meat meal, 29 fish meal, and 13 mixed meat and bone meal), 42 (12.13%) were contaminated with salmonellae. The rate of Salmonella contamination varied according to the nature of the feed sample. Seven (53.84%) of the mixed meat and bone meal, 14 (48.27%) of the fish meal, 12 (13.63%) of the feed concentrate, 7 (4.86%) of the complete feed, and 2 (4.76%) of the calcium carbonate samples contained salmonellae. The 49 Salmonella isolates represented 18 serotypes; the 5 most frequent serotypes in decreasing order were S lille, S new-haw, S livingstone, S kentucky, and S typhimurium. The 4 most common somatic serogroups encountered were C1, E2, B, and C3.

Salmonella species and serotypes isolated from farm animals, animal feed, sewage, and sludge in Saudi Arabia.

A total of 264 salmonellae representing 65 different species and serotypes were isolated for the first time in Saudi Arabia, from various animal species, animal feed, sewage, and sludge. The six most frequently isolated Salmonella species or serotypes were: livingstone, concord, "S. schottmuelleri" (invalid), lille, S. typhimurium, and cerro.

In vitro susceptibility of salmonellae to eight antimicrobial agents.

The Bauer-Kirby disk diffusion method was used to determine the susceptibility of 333 strains of Salmonella isolated in Saudi Arabia to eight antimicrobial agents. The following susceptibilities were observed: Cephalothin 99.40%, furadoine 99.10%, chloramphenicol 98.80%, ampicillin 98.20%, polymyxin 96.70%, kanamycin 95.80%, streptomycin 90.99%. Only 50.45% of the strains were susceptible to tetracycline, whereas 44.14% and 5.41% were respectively intermediate and resistant to this drug. The antibiograms displayed many resistant patterns. Some of the salmonellae were singly resistant while others were resistant to 2 or more drugs in various combinations. In view of the potential for salmonellae to have inherent or acquired resistance to certain commonly used antimicrobial agents, susceptibility of all isolates of salmonellae, particularly of all clinically significant strains should be determined periodically.