In clinical microbiology laboratories, routine microbial identification is mostly performed using culture based methodologies requiring 24 to 72 hours from culturing to identification. Matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) technology has been established as a cost effective, reliable, and faster alternative identification platform. In this study, we evaluated the reliability of the two available MALDI-TOF MS systems for their routine clinical level identification accuracy and efficiency in a clinical microbiology laboratory setting. A total of 1,341 routine phenotypically identified clinical bacterial and fungal isolates were selected and simultaneously analyzed using VITEK MS (bioMérieux, France) and Microflex LT (Bruker Diagnostics, Germany) MALDI-TOF MS systems. For any isolate that could not be identified with either of the systems and for any discordant result, 16S rDNA gene or ITS1/ITS2 sequencing was used. VITEK MS and Microflex LT correctly identified 1,303 (97.17%) and 1,298 (96.79%) isolates to the species level, respectively. In 114 (8.50%) isolates initial phenotypic identification was inaccurate. Both systems showed a similar identification efficiency and workflow robustness, and they were twice as more accurate compared to routine phenotypic identification in our sample pool. MALDITOF systems with their accuracy and robustness offer a good identification platform for routine clinical microbiology laboratories.

Thirty-six patients with Imerslund-Gräsbeck syndrome are presented. The mean ages at presentation and diagnosis were 4.7 +/- 3.7 years and 7.2 +/- 4.2 years, respectively. The mean hemoglobin level was 5.8 +/- 2.2 g/dL, the mean cell volume was 104.9 +/- 11.6 fL, the white blood cell count was 4479 +/- 2022/mm3, and the serum vitamin B12 level was 96.9 +/- 73 pg/mL. At diagnosis, 5 of the 36 patients, aged 5 to 16 years, had neurologic symptoms. All the patients had severe megaloblastic changes in bone marrow precursor cells. Proteinuria was detected in 78% of them. Patients with proteinuria had a younger age of onset (P < 0.0001) and diagnosis (P < 0.001) compared with those without proteinuria. In all patients, vitamin B12 excretion unbound to intrinsic factor after a flushing dose of vitamin B12 was lower than normal, and there was no appreciable correction in urinary vitamin B12 excretion after binding of intrinsic factor. The impairment of vitamin B12 absorption studies in Schilling tests; however, showed great variation among patients. Serum haptoglobin values were close to zero in all patients, indicating the presence of that intravascular hemolysis in Imerslund-Gräsbeck syndrome. Variations among patients in the age of presentation, degree of impairment of vitamin B12 absorption, and presence or absence of proteinuria suggest a heterogeneity in etiology of Imerslund-Gräsbeck syndrome at the molecular level.

In children with iron deficiency anemia, bactericidal capacity of polymorphonuclear leukocytes (PMN) and serum opsonic activity were studied. Nitroblue tetrazolium test (NBT), hexose monophosphate (HMP) shunt activation, and myeloperoxidase (MPO) activity of PMN of these cases were also examined. Bactericidal capacity and HMP shunt activation were found to be decreased in iron deficiency anemia (p > 0.001). MPO activity, NBT test, and serum opsonic activity were found to be within normal limits. After 1¹/₂ months of iron therapy there was an improvement in bactericidal capacity and it returned to a normal level after 3 months of therapy.

Cirrhotic patients with ascites are highly susceptible to spontaneous bacterial peritonitis. Patients with ascites due to causes other than cirrhosis very seldom develop peritonitis. The antibacterial activity of these ascitic fluids is not known. The present study was undertaken to evaluate the bactericidal and opsonic activity in ascitic fluid from patients with and without cirrhosis and in normal (nonascitic) peritoneal fluid. Normal peritoneal fluids of 20 control subjects and ascitic fluids of 22 patients with noncirrhotic ascites all had normal bactericidal activity. The bactericidal activity of ascitic fluid was diminished in all 25 patients with cirrhosis (P less than 0.00005 by Fisher's exact test). Similar results were found when opsonic activity was evaluated. Complement and immunoglobulin concentrations in cirrhotic ascites were significantly lower than those in the other two groups. The present study demonstrates that noncirrhotic ascitic fluid has antibacterial activity similar to normal peritoneal fluid, whereas cirrhotic ascitic fluid has a marked reduction of both bactericidal and opsonic activities. These defects may explain the high incidence of peritonitis in cirrhotic patients.

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