Bone marrow-restricted aberrant myeloperoxidase expression in B-acute lymphoblastic leukemia: A diagnostic dilemma and mimicry of mixed phenotype acute leukemia.

Myeloperoxidase (MPO) is the most specific marker of the myeloid lineage, essential for diagnosing acute myeloid leukemia and mixed phenotype acute leukemia with myeloid components. In this regard, we present a unique case of B-acute lymphoblastic leukemia (B-ALL) with isolated MPO expression in bone marrow blasts detected by flow cytometry and immunohistochemistry, while peripheral blood blasts were negative for MPO expression. In this report, our discussion encompasses diagnostic pitfalls from a laboratory testing perspective in similar cases and includes a literature review. Furthermore, we emphasize the necessity of conducting a comprehensive analysis for the accurate diagnosis of MPO-positive B-ALL cases.

Sterilization performance comparison between an autosampler-ready microporous filter vial and a syringe-based filter.

Herein we report that the Thomson Standard and eXtreme/FV® filter vials (0.2 µm polyvinylidene difluoride filter membrane) are as effective as gold standard microporous membrane-based syringe filters at removing bacteria, such as Klebsiella pneumonia, from media samples produced in the microbiological laboratory.

[Characterization of class 1 and class 2 integron gene cassettes in Escherichia coli strains isolated from urine cultures: a multicenter study]. / Idrar kültürlerinden izole edilen Escherichia coli suslarinda sinif 1 ve sinif 2 integron gen kasetlerinin karakterizasyonu: Çok merkezli bir çalisma.

Escherichia coli is the most common pathogen isolated from both nosocomial and community acquired urinary tract infections. Although there are many studies from different centers concerning the antibiotic susceptibility of E.coli isolates in Turkey, the studies are quite few about class 1 and class 2 integron cassettes in clinical E.coli isolates from urinary samples. The aim of the study was to investigate the antibiotic susceptibility and the carriage of integron gene cassettes in E.coli strains isolated from urinary samples. A total of 626 E.coli strains isolated from urine cultures in microbiology laboratories located at 10 provinces from different regions of Turkey (Denizli, Ankara, Kayseri, Nigde, Sanliurfa, Kahramanmaras, Tokat, Malatya, Konya and Trabzon) between June 2011-June 2012 were included in the study. The identification and antibiotic susceptibility testing of the isolates were studied by conventional methods as well as Vitek® 2 Compact (bioMérieux, France) and BD Phoenix™ 100 (Becton Dickinson, USA) systems. The antibiotic susceptibilities of all the isolates were retested by Kirby-Bauer disk diffusion method according to CLSI recommendations in the main center of the study in order to achive the standardization. The presence of integrons was detected with polymerase chain reaction (PCR) method by using specific primers targeting class 1 (intI1) and class 2 (intI2) integrase gene regions. After integron amplification the samples were cloned and subjected to DNA sequencing. When the antibiotic susceptibility of the isolates were evaluated, the highest resistance was observed against most commonly used empirical antibiotics namely ampicillin and trimethoprim-sulfamethoxazole (SXT) with the mean rate of 58.6% (range: 43.8%-73.2%) and 41.2% (range: 35.4%-45.8%), respectively. The most effective antibiotics detected against the isolates were imipenem and amikacin with the lowest resistance rates of 0.2% (range: 0%-1.1%) and 0.6% (range: 0%-3.2%), respectively. The frequency of positive IntI1 gene and class 1 integron gene cassettes were found as 25.8% (162/626) and 16.6% (104/626), respectively, whereas the frequency of positive intI2 gene II and class 2 integron gene cassettes were 5.1% (32/626) and 3% (19/626), respectively. The lowest intI1 gene frequency was detected in the isolates from Kayseri (16.6%) and the highest in the isolates from Kahramanmaras (35.4%) provinces. While there was no intI2 gene in the isolates from Denizli and Kayseri, the highest frequency was 12.1% in the isolates from Sanliurfa province. dfrA1 gene, the most frequent gene among integron gene cassettes was positive in 31 class 1 integron gene cassette alone, and positive with aadA1 gene in 18 class 1 integron gene cassettes. dfrA1 gene was positive with aadA1a just in one isolate. dfrA17 allele was positive in one isolate alone, in 28 isolates with aadA1, and in 15 isolates with aadA5. aadA1 gene was detected in four isolates. dfrA17-sat-aadA5 co-existence was detected among class 2 integron gene cassette in isolates from six provinces. dfrA1-sat-aadA1 was detected in one isolate from Ankara province and dfrA1 was detected in one isolate in Nigde province only. As a result, dfrA1 and aadA1 genes are the most common types of genes among class 1 and class 2 integron gene cassettes in E.coli isolated from urine cultures. It was concluded that high resistance against streptomycin (31.2%) and SXT (41.2%) supported the dissemination of integron-mediated genes dfr, sul1 and aad in the isolates.

[Effect of cigarette smoke extract on phagocytosis of Staphylococcus aureus by macrophages]. / Staphylococcus aureus'un makrofajlar tarafindan fagositozu üzerine sigara dumani ekstraktinin etkisi.

Staphylococcus aureus is one of the most important pathogen that causes community acquired and nosocomial infections worldwide. Phagocytosis by macrophages plays an important role in the first line defense against infections caused by S.aureus. On the other hand, the conducted studies have indicated that cigarette smoke has negative effects on both innate and acquired immune responses. The aim of this study was to investigate the effects of cigarette smoke on macrophage viability and their capacity of S.aureus phagocytosis. For this purpose THP-1 cell lines (human leukemic monocyte cell culture) were used and after the differentiation of the cells with PMA (phorbol myristate acetate) treatment, the macrophages were exposed to cigarette smoke extract (CSE) for 2- and 4-hours at concentrations of 1%, 5%, 10%, 25%, and 50%. Afterwards, the cells were stained with propidium iodide and the viability of the cells was analyzed by a flow cytometer. Two different methods were used to investigate the effect of CSE on the phagocytosis of S.aureus. The first one was the classical bacteriological method, in which macrophages were exposed to CSE for 2 hours in five different concentrations and were infected with 100 MOI (multiplicity of infection) S.aureus. After 1 hour of incubation, macrophages were lysed with PBS-0.1% Triton X-100 and plated on Luria-Bertani (LB) agar following serial dilutions. Newly formed colonies were counted and the number of bacteria phagocytosed were evaluated as colony forming units (CFU). The second method for the detection of phagocytosis was flow cytometric analysis in which SYBR(®) Green-labeled bacteria were used. To confirm that the macrophages were infected, bacteria were stained with SYBR(®) Green and macrophages were analyzed following infection via flow cytometry. Macrophages were exposed to 10% and 50% CSE and infected with bacteria stained with SYBR(®) Green. The level of phagocytosis was analyzed by flow cytometry in terms of median fluorescence intensity. Macrophage death rate was 24% and 30% following 2-hour exposure to 25% and 50% CSE, respectively, while 4-hour exposure increased death rate to 38% and 51%, respectively (p< 0.001). At 10% and higher concentrations of CSE, cell death increased with an average of 1.5-fold between 2- and 4-hour exposures (p< 0.05). Macrophages were successfully infected (99.8%) with SYBR(®) Green-stained S.aureus. Phagocytosis of S.aureus by macrophages decreased significantly upon exposure to 10% or more CSE concentrations (p< 0.0001). Median fluorescence intensity, which indicates phagocytosed bacterial cell number, decreased with no statistical significance when macrophages exposed to 10% and 50% CSE were infected with SYBR(®) Green-stained S.aureus. The results of this study revealed that, macrophage viability and phagocytosis of S.aureus were reduced depending on CSE concentration and time of exposure. In addition, it was shown that, SYBR(®) Green dye is a proper stain for the flow cytometric analysis of bacteria that were phagocytosed by macrophages.

Nationwide study of Escherichia coli producing extended-spectrum ß-lactamases TEM, SHV and CTX-M in Turkey.

Four hundred and forty extended-spectrum ß-lactamase (ESBL)-producing Escherichia coli isolates were collected from 10 different hospitals in Turkey between 2011 and 2012. Clinical specimens consisted of urine (80.45%), blood (6.59%), cerebrospinal fluid (1.13%), pleural fluid (2.95%), wound (4.31%) and sputum (4.54%). ESBL-coding genes (CTX-M1, CTX-M2, TEM, SHV) were detected by PCR. According to the PCR and sequencing results, CTX-M1 was the most prevalent ß-lactamase 83.18% (366/440), followed by TEM 44.09% (194/440), CTX-M2 31.81% (140/440) and SHV 1.81% (8/440). Sequencing results showed that TEM and SHV types were TEM-1b and SHV-11, respectively. Rate of the strains harboring only CTX-M1, CTX-M2, TEM-1b and SHV-11 were 30.90%, 3.63%, 2.27% and 0.23%, respectively. Rate of the strains harboring the combinations of CTX-M1-CTX-M2, CTX-M1-CTX-M2-TEM-1b, CTX-M2-TEM-1b, CTX-M1-TEM-1b, CTX-M1-CTX-M2-TEM-1b-SHV-11, CTX-M1-TEM-1b-SHV-11, CTX-M1-SHV-11, CTX-M1-CTX-M2-SHV-11, CTX-M2-SHV-11, CTX-M2-TEM-1b-SHV-11, TEM-1b-SHV-11 were 12.95%, 11.59%, 2.95%, 26.13%, 0.45%, 0.68%, 0.22%, 0.22%, 0%, 0% and 0%, respectively. This is a nationwide study of ESBL-producing E. coli in Turkey. These results shows that CTX-M1 group is the most common type of class A ß-lactamases among ESBL-producing E. coli strains in Turkey.