AIM: The objective of this study was to determine the pathogenicity of Salmonella enterica subspecies enterica serovar Enteritidis (SE) phage type (PT) 1 in one-day-old specific pathogen-free (SPF) chicks.
METHODS: Seventy, one-day-old SPF chicks, were divided into SE group (30 chicks), mortality group (10 chicks), both orally inoculated (1.0 ml) with SE PT1 (1 × 108 colony-forming unit per 1.0 ml), and one control group (30 chicks). The chicks were sacrificed at 6 and 12 hours, and days 1, 2, 3, 5, 7, 10, 14, and 21 post-inoculation (pi). Samples were collected for bacterial isolation, histological examination, and ultrastructural examination.
RESULTS: Starting from day 2 pi, the body weight in the SE group significantly (p < 0.05) decreased. The SE isolation percentages from the liver, spleen, mid-intestinal content, cecal content, cecal tonsil, blood, and cloacal swab were 0.73, 0.77, 0.33, 0.33, 0.36, 0.40, and 0.30, respectively. The isolation percentage in the liver was significantly (p < 0.05) higher than the blood and cloacal swab. The villi heights and crypt depths in the SE group were significantly (p < 0.05) greater and smaller, respectively. Ultrastructurally, erosion and necrosis were observed in the microvilli of the cecal tonsil. The bacteria were engulfed by macrophages at the interepithelial clefts of the M-like M cells.
CONCLUSION: It was concluded that the inoculation of SE PT 1 in one-day-old chicks caused a systemic infection with diarrhea, a decrease in the body weight and villi height in the duodenum, jejunum, and ileum, and high bacterial loading in the liver with mild gross and histological lesions of organs, erosion, and necrosis of microvilli and low mortality. The bacteria entered the body system from the intestinal tract through the interepithelial clefts of the M-like M cells of the cecal tonsil.
Materials and Methods: This study utilized 10 LAB previously isolated from fermented buffalo milk (dadih), fermented fish (budu), and fermented cassava (tape) which have the ability to produce gamma-aminobutyric acid. The study commenced with the screening of LAB for certain properties, such as resistance to acid and bile salts, adhesion to mucosal surface, and antagonism against enteric pathogens (Escherichia coli, Salmonella Enteritidis, and Staphylococcus aureus). The promising isolates were identified through biochemical and gram staining methods.
Results: All isolates in this study were potential novel probiotics. They survived at a pH level of 2.5 for 3 h (55.27-98.18%) and 6 h (50.98-84.91%). Survival in bile at a concentration of 0.3% was 39.90-58.61% and the survival rate was 28.38-52.11% at a concentration of 0.5%. The inhibitory diameter ranged from 8.75 to 11.54 mm for E. coli, 7.02 to 13.42 mm for S. aureus, and 12.49 to 19.00 mm for S. Enteritidis. All the isolates (84.5-92%) exhibited the ability to adhere to mucosal surfaces. This study revealed that all the isolates were potential probiotics but N16 proved to be superior because it was viable at a pH level of 2 (84.91%) and it had a good survival rate in bile salts assay (55.07%). This isolate was identified as Lactobacillus spp., Gram-positive bacilli bacteria, and tested negative in both the catalase and oxidase tests.
Conclusion: All the isolates in this study may be used as probiotics, with isolate N16 (Lactobacillus spp.) as the most promising novel probiotic for poultry applications based on its ability to inhibit pathogenic bacteria.
METHODS: A retrospective study identifying all children aged Salmonella infections from 2011 to 2016 was conducted in Bintulu Hospital in Sarawak. Population incidences, clinical and bacterial characteristics were examined.
RESULTS: Forty-four patients were identified during the 6-year study period: 43 had iNTS infection and 1 had typhoid fever. The average annual iNTS incidence was 32.4 per 100,000 children aged Salmonella Enteritidis and Salmonella Java were the commonest NTS serovars identified. Pneumonia was the most common manifestation of iNTS disease, present in 20 (47%) children. Other manifestations included gastroenteritis, fever without a source, septic arthritis and meningitis. Salmonella Enteritidis was identified in 76% of those with pneumonia, significantly more frequently than in children with other manifestations. Over 25% of children with iNTS developed severe disease and nearly 10% suffered long term morbidity or mortality. While 78% of Salmonella Java isolates were multi-drug resistant, nearly all other isolates were susceptible to most antimicrobials, including ampicillin.
CONCLUSIONS: Bintulu Division in Sarawak observed a very high incidence of childhood iNTS infections. Enteric fever was uncommon. The epidemiology of invasive Salmonella infections in Malaysian Borneo differs considerably from that of neighbouring countries in Asia.