Through proteomics techniques, this study identified four proteins in the chronic typhoid carrier host that may have a role in the disease pathogenesis of enteric fever.
Salmonella enterica serovar Typhi faces several environmental stresses while going through the stomach (acidic pH) to the small intestine (basic pH) and intracellularly in macrophages (acidic pH) in humans. The acidic pH followed by alkaline pH in the small intestine might be responsible for expression of certain stress-induced genes, resulting in not only better survival but also induction of multiplication and invasion of the bacterium in the small intestine. Based on this hypothesis, we developed a process wherein we exposed the blood, urine, and stool specimens from 90 acute typhoid fever patients and 36 chronic typhoid carriers to acidic pH to see the effect on isolation rate of S. Typhi. About 5 g of freshly passed unpreserved stool, a centrifuged deposit of 15 ml of urine, and 5 ml of blood clot were subjected to 5 ml of Luria-Bertani (LB) broth (pH 3.5) for 20 min, followed by enrichment in bile broth-selenite F broth. When the combined isolation from all 3 specimens, i.e., blood, urine, and stool, after acid exposure was considered, a total of 77.7% of the acute typhoid patients were observed to be positive for the isolation of the S. Typhi serotype, compared to 8.8% by the conventional method. Similarly, 42% (15/36) of chronic carriers yielded positive for S. Typhi growth after acid exposure, compared to 5.5% (2/36) by the conventional method. It therefore can be concluded that acid shock triggers the multiplication of the bacteria, resulting in better isolation rates from blood clot, stool, and urine specimens. The estimated global incidence of typhoid fever is about 26.9 million new cases with 1% mortality annually (1). This seems to be a gross underestimate, due to poor availability and performance of diagnostics in countries where typhoid is endemic (2). The available laboratory methods, i.e., bacterial culture, serological markers, antigen detection, and nucleic acid amplification, are highly unsatisfactory in the field conditions. There is an urgent need for optimization of culture methods because of the absolute specificity of culture isolation. High density (bone marrow) or large volume (Ͼ30 ml of peripheral blood) have been reported with satisfactory levels of sensitivity for Salmonella enterica serovar Typhi/Paratyphi isolated from acute typhoid fever cases. In patients with acute typhoid fever, the bacterial density has been reported to be 10-fold higher in bone marrow than in peripheral blood (3). However, both of the above options, i.e., higher blood volume or bone marrow aspirations, are not practical, even at the tertiary level of health care settings. Interestingly, a study from Vietnam reported a median count of 0.1 to 1.0 CFU of S. Typhi/ml of blood (range, 0.3 to 387) in cases of acute typhoid fever (4). It means 5 ml of routinely collected blood should have at least 5 bacterial cells sufficient enough to grow in artificial medium that are devoid of all antibacterial factors present in vivo. In routine practice, we hardly exceed 30% of the isolation rate of S. Typhi with the above-me...
Background: Neonatal septicemia still a major cause of mortality and morbidity worldwide. Blood culture is the main stay in the diagnosis of septicemia. Emergence of drug resistant bacterial strains is a major problem in the management of sepsis. Aim of present study is to determine bacteriological profile and antibiotic resistance in neonatal sepsis. Method: The study was carried out in the Department of Microbiology, MGM, Medical College Indore during the period from January 2017 to June 2017. 450 blood samples collected from clinical suspected cases of bacteremia were studied. Growth from the subcultures were identified by standard biochemical testing and antibiotics resistance pattern were determined as per Clinical Laboratory Standard Institute (CLSI) guidelines. Result: During that period, a total of 176 (39%) blood samples were found to be positive for bacterial isolates. Gram negative septicemia (50.5%) was encountered slightly more than gram positive septicemia (49.5%). The common bacteria isolated were Klebsiella spp., CONS, Staphylococcus aureus and Escherichia coli. Antibiotics resistance against gram negative bacilli were cefuroxime, ceftazidime, cefepime and ciprofloxacin. Gram-positive isolates showed excellent sensitivity to linezolid and vancomycin Conclusion: The study concludes that the isolated organism exhibited higher resistance towards commonly used antimicrobials. Healthcare personnel and common population should also be aware of the rising antibiotic resistances to frequently used antibiotics.
Background: Typhoid is a disease affecting a large population throughout the world. Besides poverty, low education level and poor hygiene, contact with typhoid patient or a carrier has been identified as major risk factors. Approximately 2-5% of typhoid patients do not clear the infection and progress to carrier state. Stool culture is an important method of diagnosis in such cases. However the yield can be very low and many cases can be missed. Confirmed diagnosis and prompt treatment are essential to control the spread of typhoid.
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