ABSTRACT
LysR-type transcriptional regulators are involved in the regulation of numerous cellular metabolic processes in Klebsiella pneumoniae, leading to severe infection. Earlier, we found a novel LysR family gene, named kp05372, in a strain of K. pneumoniae (designated GPKP) isolated from forest musk deer. To study the function of this gene in relation to the biological characteristics of GPKP, we used the suicide plasmid and conjugative transfer methods to construct deletion mutant strain GPKP-Δkp05372; moreover, we also constructed the GPKP-Δkp05372+ complemented strain. The role of this gene was determined by comparing the following characteristics of three strains: growth curves, biofilm formation, drug resistance, stress resistance, median lethal dose (LD50), organ colonization ability, and the histopathology of GPKP. Real-time polymerase chain reaction (RT-PCR) was used to test the expression level of seven genes upstream of kp05372. There was no significant difference in the growth rates when comparing the three bacterial strains, and no significant difference was recorded at different osmotic pressures, temperatures, salt contents, or hydrogen peroxide concentrations. The GPKP-Δkp05372 mutant formed a weak biofilm, and the other two strains formed medium biofilm. The drug resistance of the GPKP-Δkp05372 mutant toward cephalothin, cotrimoxazole, and polymyxin B was changed. The acid tolerance of the deletion strain was stronger than that of the other two strains. The LD50 values of the wild-type and complemented strains were 174-fold and 77-fold higher than that of the GPKP-Δkp05372 mutant, respectively. The colonization ability of the GPKP-Δkp05372 mutant in the heart, liver, spleen, kidney, and intestine was the weakest. The three strains caused different histopathological changes in the liver and lungs. In the GPKP-Δkp05372 mutant, the relative expression levels of kp05374 and kp05379 were increased to 1.32-fold and 1.42-fold, respectively, while the level of kp05378 was decreased by 42%. Overall, the deletion of kp05372 gene leads to changes in the following: drug resistance and acid tolerance; decreases in virulence, biofilm formation, and colonization ability of GPKP; and regulation of the upstream region of adjacent genes.
Subject(s)
Animals , Female , Male , Mice , Bacterial Proteins/physiology , Biofilms , Deer/microbiology , Drug Resistance, Bacterial , Klebsiella Infections/pathology , Klebsiella pneumoniae/growth & development , Transcription Factors/physiologySubject(s)
Adolescent , Humans , Klebsiella/isolation & purification , Klebsiella Infections/complications , Klebsiella Infections/diagnosis , Klebsiella Infections/pathology , Lymphohistiocytosis, Hemophagocytic/complications , Lymphohistiocytosis, Hemophagocytic/diagnosis , Lymphohistiocytosis, Hemophagocytic/pathology , Male , Microscopy , Parvoviridae Infections/complications , Parvoviridae Infections/diagnosis , Parvoviridae Infections/pathology , Parvovirus B19, Human/isolation & purificationABSTRACT
Two cases of pulmonary gangrene involving left lower lobe in an 18-month and 4-year-old female children are reported. The patients looked like having empyema following Klebsiella pneumonia. The diagnosis was made following computerized tomography scan and during decortication respectively.
Subject(s)
Child, Preschool , Diagnosis, Differential , Empyema, Pleural/diagnosis , Female , Gangrene/pathology , Humans , Infant , Klebsiella Infections/pathology , Klebsiella pneumoniae , Lung/pathology , Pneumonia, Bacterial/pathologyABSTRACT
An unusual case of extradural, intraspinal Ewing's sarcoma with significant extraspinal extension is reported. In view of associated constitutional symptoms, suggestive signs, leucocytosis, elevated ESR and operative findings, the initial diagnosis of Pott's spine was entertained. The lesion however turned out to be infected Ewing's sarcoma on histopathology and bacteriological examination.
Subject(s)
Child , Female , Humans , Klebsiella Infections/pathology , Leukocytosis/pathology , Magnetic Resonance Imaging , Sarcoma, Ewing/microbiology , Spinal Neoplasms/microbiologyABSTRACT
Cancrum oris (noma) has been most commonly described in malnourished debilitated children with poor oral hygiene following systemic childhood infections such as measles, pertussis or scarlet fever. We describe a patient who developed this condition during a period of profound neutropenia following cytotoxic chemotherapy for acute lymphoblastic leukaemia.