Investigation of dense fine speckled pattern and anti-dense fine speckled 70 antibody by a single step assay

The indirect immunofluorescence (IIF) method is the gold standard for identifying anti-nuclear antibodies (ANAs). It is recommended that ANA, including the dense fine speckled (DFS) pattern, should be verified with a highly specific confirmatory test after a sensitive screening test. Although methods such as ELISA and LIA are often used to confirm the presence of anti-DFS70 antibodies, new IIF methods have been developed in recent years to prevent the difficulties in the recognition of the DFS pattern and to carry out the confirmatory test in a single step. In this study, we evaluated CytoBead (Generic Assays, Germany) test, which contained both HEp-2 cell substrate and beads coated with DFS70 antigen in one well, in comparison to the routine two-step test strategy. Five hundred forty-one samples were studied by conventional IIF assay, LIA, and CytoBead assay; 264 samples were studied by ELISA. The Bead component of the CytoBead test was found to be reliable as a confirmational test when compared with ELISA and LIA (total agreement values were 85.6% and 87.6%, respectively). The CytoBead ANA DFS70 might be a promising test in the future, allowing both screening and confirmation in a single step, saving time and being easier than two-step testing.

[Evaluation of the Methods Used for the Detection of Entamoeba histolytica in Stool Samples of Patients with Diarrhea]

Amoebic dysentery (amebiasis) is a parasitic infection caused by Entamoeba histolytica. The diagnosis of invasive amebiasis has traditionally been based on direct and stained microscopic examination of stool samples. Stool microscopy exhibits low sensitivity and it is difficult to distinguish E.histolytica cysts and trophozoites from cells such as leukocytes, macrophages and non-pathogenic Entamoeba species in the stool by microscopy. Therefore more sensitive and specific diagnostic methods such as enzyme linked immunosorbent assay (ELISA) tests which investigate the presence of E.histolytica-specific antigen in stool, and polymerase chain reaction (PCR) are being widely used. In this study it was aimed to study stool samples of the patients who applied with the clinical signs of amebiasis by using direct and permanent stained microscopy, E.histolytica adhesin antigen ELISA test and real-time PCR-based BD Max Enteric Parasite Panel (BD Max EPP) test and to evaluate the diagnostic values of these tests. A total of 546 faecal samples with blood and/or mucus were analyzed in the study. In these samples, the presence of E.histolytica was investigated by direct and permanent stained microscopy, E.histolytica adhesin antigen ELISA and BD Max EPP PCR. Of the samples 36.3% were suspected to contain E.histolytica/dispar/moshkovskii cyst and/or trophozoite by direct microscopic examination. Trichrome staining was performed on these samples and 49 samples were found suspicious for the presence of E.histolytica/dispar/moshkovskii cysts and/or trophozoites. The presence of E.histolytica and other Entamoeba species was not confirmed in 75.2% of the samples. BD Max EPP PCR and E.histolytica adhesin antigen ELISA tests were studied in 49 faecal samples that were suspected by trichrome staining. None of these samples were positive by ELISA. Forty-four samples were negative by PCR and invalid test results were obtained in five samples. In this study, E.histolytica was not detected in the patient population. The results of this study showed that microscopic examination alone is not sufficient for the detection of E.histolytica. It is concluded that it is necessary to use a more sensitive and specific also rapid diagnostic test such as E.histolytica-specific antigen detection test or PCR in the diagnosis of amebiasis to avoid misdiagnosis and unnecessary treatment of patients.

POS1221 EFFECT OF COVID-19 ON CHILDREN WITH RHEUMATIC DISEASE

Background

Pediatric patients with a diagnosis of rheumatic disease are at increased risk for infectious diseases due to immune dysregulation arising fromthe disease itself, as well as immunoregulatory or immunosuppressive drugs they use. However, there are studies reporting that COVID-19 disease has a moderate course in children with rheumatic disease.

Objectives

This study aims to determine the seroprevalence of SARS-CoV-2 in children with rheumatic disease during the COVID-19 pandemic, to evaluate the effects of immunosuppressive drugs and biological agents on seroprevalence of COVID.

Methods

Between September 2020 and September 2021, patients aged 2-18 years with a diagnosis of and with a follow-up period of more than 6 months were included in the study. Patients were selected by “simple random sampling” method.

Anti-SARS-CoV-2 antibodies (IgG and IgA) against the S1 domain of the SARS-CoV-2 spike protein were investigated with a micro ELISA kit.

Results

170 patients, 92 (54.1%) girls, with a mean age of 12.16±4.18 years, were included. The median age at diagnosis was 7.59 (IQR 4.33-11.30) years, and the median follow-up time after diagnosis was 3.24 (IQR 1.87-5.99) years. Primary disease distribution was presented on Figure 1. The co-morbid diseases as obesity, hypertension and chronic kidney disease was present in 4.7%, 9.4% and 5.3% of patients, respectively. The distribution of medications was as follows; colchicine 101 patients (59.4%), Disease Modifying Anti-Rheumatism Drugs 49 (28.8%), steroid 25 (14.7%), and biological agents 28 (16.5%).

Figure 1.

Distribution of patients according to primary rheumatologic diagnosis

Anti-SARS-CoV-2 Ig G antibody was positive in 40 (23.5%) of the patients. Demographic characteristics and treatment-related variables were similar between SARS-CoV-2 IgG seropositive and seronegative patients (Table 1).

Table 1.

Characteristics of patients who are seropositive and seronegative for anti-SARS-CoV-2 Ig G

VariableAnti-SARS-CoV-2 IgG negative patients (n=130)Anti-SARS-CoV-2 IgG positive patients (n=40)pAge (years)11.96±4.1912.80±4.140.528Sex (%)Female67 (%72.8)25 (%27.2)0.150Median age at diagnosis (years)7.56±4.038.69±4.750.195Median follow-up time after diagnosis (years)4.39±3.274.11±3.190.891Diagnosis (%) FMF and other autoinflammatory disease62 (%78.5)17 (%21.5)0.166 Juvenile idiopathic arthritis39 (%78.0)11 (%22.0) SLE ve other autoantibody related diseases16 (%80.0)4 (%20.0) Behçet’s disease8 (%66.7)4 (%33.3) Vasculitis5 (%55.6)4 (%44.4)MEFV mutation Homozygous30 (%75.0)10 (%25.0)0.991 Heterozygous33 (%76.7)10 (%23.3) No mutation36 (%75.0)12 (%25.0)Presence of colchicine usageYes76 (%75.2)25 (%24.8)0.396No54 (%78.2)15 (%21.7)Median colchicine dose (mg/day)1.09±0.441.13±0.420.842Presence of DMARD usageYes37 (%75.5)12 (%24.5)0.499No93 (%76.9)28 (%23.1)Presence of steroid usageYes17 (%68.0)8 (%32.0)0.202No113 (%77.9)32 (%22.1)Median steroid dose (mg/day)10.50±8.9114.71±11.950.333Presence of biological agent usageYes21 (%75.0)7(%25.0)0.505No109 (%76.8)33(%23.2)

Thirty-eight (22.4%) of the patients had close contact with an individual diagnosed with COVID-19. Thirty two (18.9%) patients underwent PCR testing for SARS-CoV-2; only 4 (2.4%) had positive. Of these 32 patients, 28.1% were positive for IgG. IgG seropositivity was observed in 3 (75.0%) of 4 patients with PCR positivity.

Conclusion

We found the SARS-CoV-2 seroprevalence of 23.5% in children with a diagnosis of rheumatic disease. It seems that primary rheumatological diagnosis does not affect COVID seropositivity in children.

Disclosure of Interests

None declared

Incidence of BKV in the urine and blood samples of pediatric patients undergoing HSCT

The aims were to investigate the incidence of BKV infection and the presence of HC in pediatric patients undergoing HSCT. Twenty-four children patients (M/F: 17/7) undergoing HSCT in a single center over a period of 1 year were included in the study. The presence of BKV DNA was determined by quantitative real-time PCR in plasma and urine samples at the following times: before transplantation, twice a week until engraftment time, and weekly for + 100 days. The mean age of the patients was 7.79 ± 5.03 years, the mean follow-up time was 95.6 ± 25.9 days, and the average number of samples per patient was 15.8 ± 3.2. BKV DNA was detected in at least one urine sample in 91.6% (n: 22) and at least one plasma sample in 75% (n:18) of the patients. The median time to the first BKV DNA positivity in urine and plasma samples was 11 (range: 1-80) and 32 days (range: 2-79), respectively. The median value of BKV DNA copies in urine and plasma were 1.7 × 10⁶ (range: 2.8 × 10¹ -1.2 × 10¹⁴ ) and 1.9 × 10³ copies/mL (range: 3-2.1 × 10⁶ ), respectively. Thirteen patients (54.2%) had hematuria with BKV viruria; 8 (33.3%) patients had viremia. The median value of the BKV DNA copies in urine and plasma was 4.4 × 10⁷ (range: 65-1 × 10¹¹ ) and 2.9 × 10³ (range: 7-7.8 × 10⁴ ) copies/mL in these patients. Two (15.4%) of the 13 patients with BKV viruria and hematuria were diagnosed with BKV-related HC. BKV DNA viral load monitoring of urine and plasma in pediatric HSCT patients with a high risk for viral infections is valuable for understanding the development of BKV-related HC.

[Distribution of Hepatitis C Virus (HCV) Genotypes Among Intravenous Drug and Non-Drug User Patients]

Genotype distribution of hepatitis C virus (HCV) can vary over the years between different patient groups and regions. The prevalence of intravenous drug users (IVDU) is known to increase in our country, yet there are a limited number of studies investigating the distribution of HCV genotypes in this group. These data are essential for monitorization of the changes in HCV epidemiology. The present study aimed to evaluate the five-year results of HCV genotyping among patients infected with HCV related to IVDU and unrelated to drug use. Plasma samples of 720 patients (HCV antibody, HCV RNA positive), which were sent to our laboratory for HCV genotyping between January 2014-March 2019 were analyzed. HCV RNA extraction from plasma samples was performed in the automated-extraction system of EZ1 advanced (Qiagen, Germany) using the EZ1 virus mini kit v2.0 (Qiagen, Germany). Amplicons were obtained by amplifying the 5'NCR and core gene region in the Rotorgene 6000 real-time PCR (Qiagen, Germany) device with the HCV RNA real-time quantitative 2.0 (NLM, Italy) kit. For the genotyping, a commercial line probe assay (LIPA) based on in vitro reverse hybridization GEN-C2.0 kit (NLM, Italy) which can distinguish 1, 2, 3, 4, 6 genotypes and 1a, 1b, 2a/c, 2b, 3a, 3b, 3c, 3k, 4a, 4b, 4c/d, 4e, 4f, 4h, 5a, 6a/b, 6g, 6f/q, 6m, 7a subtypes of HCV, based on variations in the 5'-NCR and core regions was used. HCV genotype distribution of 266 IVDU (93.2%: male; median age: 25 ± 6.82) and 454 non-drug users (51.3%: male; median age: 56.5 ± 16.06) were examined. In order of frequency in the group with IVDU; genotype 1a, 3a, 1b, 4c/d, 2b, 4, 3 were observed and genotype 1, 2a/c and mixed genotype (1+3a) were detected in one patient. In the group without IVDU, in order of frequency; genotype 1b, 1a, 3a, 1, 2a/c, 4 were observed and genotype 2b, 4c/d, 5a, 6a/b, 6 and mixed genotype (3+4) were detected in one patient. Genotypes 1a and 3a were significantly higher in the IVDU group (p< 0.00001, p< 0.00001), while 1b was significantly higher in patients without IVDU (p< 0.00001). Genotypes 1a and 3a were more common in young men (p< 0.00001, p= 0.000163), while 1b was higher in middleaged women (p< 0.00001). The incidence of genotypes 1b (p= 0.021) and 3a (p= 0.012) was higher in foreign nationals than the Turkish patients. When the HCV genotype distribution was examined by years, it was observed that the percentages of genotype 1b and 1a were decreasing, while the percentage of genotype 3a was increasing. As a result, in this study, HCV genotype distribution among IVDU was observed to be different from the general population without IVDU. It was found that genotypes 1a and 3a were more common in the IVDU group. As in the other regions of our country, genotype 1b was found most frequently in the general population. Genotype 3a increases significantly compared to years. In our study, the determination of genotypes existing in different parts of the world may be due to the foreign nationals living in our city and our region is a tourism center. It is also necessary to investigate whether there is an increase in IVDU over the years.

[Evaluation of a Commercial Multiplex Tandem Polymerase Chain Reaction Method for the Identification of the Yeasts Isolated from Blood Cultures]

Candidemia is one of the most important health care-associated infections worldwide. Candida species have species-specific antifungal susceptibility profiles and it has been shown that the identification of the Candida species is necessary for the appropriate treatment of the patients with candidemia. Various methods are used to shorten the identification time for the determination of the causative species. Fungal ID multiplex tandem polymerase chain reaction (MT-PCR) (AusDiagnostics, Australia) is a test developed to identify yeasts and molds isolated from clinical specimens. In this study, we aimed to evaluate the Fungal ID MT-PCR test (AusDiagnostics, Australia) for the identification of the yeasts from positive blood cultures in Akdeniz University Hospital Central Laboratory. Between December 2016 and December 2017, blood culture samples from 92 consecutive patients with yeast cells detected in Gram stained smears were tested by Fungal ID MT-PCR and the reference method. After the subculture of the positive signaling blood culture bottles to Sabouraud dextroz agar (SDA), the identification of the yeasts were performed by morphological identification methods (Germ tube test, Corn Meal Tween® 80 agar media, etc.), BD Phoenix Yeast ID Panel (Becton Dickinson, Sparks, MD) and Bruker Biotyper matrix-assisted laser desorption ionization-time of mass spectrometry (MALDI-TOF MS) (Bruker Daltonics, Germany) systems. Identification with MALDI-TOF MS have been accepted as the reference method. Thirty-five of the isolates were identified as Candida albicans, 17 were Candida glabrata, 13 were Candida parapsilosis, 12 were Candida tropicalis, seven were Candida krusei , two were Candida guilliermondii, two were Candida dubliniensis, two were Candida inconspicua, one was Candida kefyr and one was Saprochaete capitata by the reference method. In our study, no blood culture sample yielded more than one yeast species. 94.6% of the strains were presumptively identified by the morphological identification methods. Discordant results were not detected between the BD Phoenix Yeast ID Panel and the reference method. Thirty-three of the isolates were identified as C.albicans, 15 were C.glabrata, 13 were C.parapsilosis, 11 were C.tropicalis, five were C.krusei , two were C.guilliermondii, one was C.dubliniensis, one was C.kefyr and 10 were Candida spp. by Fungal ID MT-PCR assay. Since C.inconspicua and S.capitata were not included in the test panel, C.inconspicua was identified as Candida spp. in two samples, while S.capitata could not be identified in one sample. Concordance between Fungal ID MT-PCR and the reference method were found to be 88% at the species level and 98.9% at the genus level. The sensitivity of the Fungal ID MT-PCR test in in the detection of C.krusei and C.glabrata was 71.4% and 88.2%, respectively. Fungal ID MT-PCR test has shown a high performance in the identification at the genus level, but the identification at the species level, which is important for the treatment management, was moderate. Fungal ID MT-PCR can be used as an adjunct test to the traditional identification methods for the early identification of the Candida species.

Viral seroprevalence in pediatric kidney transplant recipients

AIM

Viral infections commonly affect kidney transplant recipients and may lead to graft failure and death. The aim of this study was to evaluate the antibody seroprevalence against viral agents in kidney transplant recipients.

MATERIAL AND METHODS

The records of children who underwent kidney transplantation between 2008 and 2018 in Akdeniz University Faculty of Medicine were retrospectively reviewed. Epstein-Barr virus, cytomegalovirus, hepatitis A virus, hepatitis B virus, varicella, measles, rubella and mumps serologies evaluated before transplantation, were recorded. The clinical characteristics of seronegative and seropositive patients were compared, and factors that affected seropositivity were investigated.

RESULTS

The study included 253 children with a mean age of 16.7±6.23 years. The mean age at transplantation was 11.4±5.01 years. The seropositivity rates for vaccine-preventable viral infections varied: hepatitis B 89.7%, hepatitis A 60.5%, measles 78.7%, rubella 88.1%, mumps 61.2%, and varicella 71.9%. Cytomegalovirus seropositivity was 92.1% and Epstein-Barr virus seropositivity was 82.2%. Hepatitis B antibody positivity was 91.8% in patients undergoing hemodialysis, 94.5% in patients undergoing peritoneal dialysis, and 84.9% in pre-emptive transplantation patients (p=0.037). The mean age at transplantation was higher in patients with seropositivity for both cytomegalovirus and Epstein-Barr virus compared with seronegative patients (p<0.001 for both). The mean age at transplantation and diagnosis of glomerular disease was found to be effective for varicella seropositivity in multivariate regression analysis (OR 0.860, 95% CI: 0.808-0.915, p<0.001 and OR 2.502, 95% CI: 1.321-4.739, p=0.005, respectively).

CONCLUSION

It is important to screen patients with chronic kidney disease in terms of vaccine-preventable diseases to identify risky groups of patients and to immunize these patients before end-stage kidney disease develops.

The Evaluation of the Performance of C. Diff Quik Chek Complete and Toxin A + B (Clostridium difficile) DUO Diagnostic Tests Compared with Toxigenic Culture in the Diagnosis of Clostridium difficile Infection

BACKGROUND

Clostridium difficile is an important cause of nosocomial diarrhea and the best standard laboratory method for the diagnosis of C. difficile infection is controversial. In this study, we aimed to investigate the performance of Toxin A + B (Clostridium difficile) DUO kit which detects C. difficile toxin A and B by the immunochromatographic method and C. Diff Quik Chek Complete (QCC) rapid membrane immunoassay kit which determines the presence of glutamate dehydrogenase (GDH) and C. difficile toxin A and B in stool samples, compared with toxigenic culture in the diagnosis of C. difficile infection.

METHODS

One hundred ninety-three stool samples from patients suspected of having C. difficile infection were included in the study. The performances of two commercial tests were compared with toxigenic culture which was accepted as the reference method.

RESULTS

The sensitivity and specificity of the GDH component of QCC were 94.4% and 97.7%, the sensitivity and specificity of the toxin component were 92.3% and 100%, respectively. The sensitivity and specificity of Toxin A + B (Clostridium difficile) DUO test were found as 53.8% and 87.8%, respectively.

CONCLUSIONS

C. Diff Quik Chek Complete test, which is a rapid test with high sensitivity and specificity, can be used alone for the diagnosis of C. difficile infection while Toxin A + B (Clostridium difficile) DUO test cannot be used for the same purpose due to the low sensitivity and specificity of the test.

[Evaluation of Microscopic Examination, Culture and Polymerase Chain Reaction Tests in the Diagnosis of Trichomonas vaginalis Infection]

Sexually transmitted infections (STIs) are important as a public health problem all over the world. There are some difficulties in prevention and control programs of STIs due to clinical and laboratory diagnostic problems.The most common STIs are Chlamydia trachomatis infections, trichomoniasis and gonorrhea. The study aimed to investigate the direct microscopic examination, culture and polymerase chain reaction (PCR) tests in the diagnosis of Trichomonas vaginalis infection; to determine other microbiological agents that may cause vaginal discharge and to evaluate the various social variables in women with vaginal discharge admitted to the outpatient clinic of Obstetrics and Gynecology in Akdeniz University Hospital. Two hundred and fifteen patients were enrolled in the study. The socio-demographic features of the patients were recorded. Vaginal/endocervical swab specimens taken from patients were evaluated by microscopic examination. Swab specimens were inoculated into blood agar, MacConkey agar and chocolate agar for bacterial culture. Modified Trichosel broth with 5% horse blood (Becton Dickinson, USA) was used for Trichomonas spp. culture. The presence of C.trachomatis, Neisseria gonorrhoeae, and T.vaginalis in swab samples were investigated by multiplex PCR assay (BD Max CT/GC/TV, Becton Dickinson, USA). At least one pathogen was detected among 65 (30.3%) samples. T.vaginalis was detected by microscopic examination and PCR in four of 215 (1.9%) patients. Existence of yeast morphology was observed in 21 (9.8%) specimens by microscopic examination. Twenty four (11.2%) patients were diagnosed as bacterial vaginosis microscopically according to Nugent score system. Candida species grew in 32 (14.9%) and Streptococcus agalactiae grew in 2 (0.9%) of the specimens. C.trachomatis was detected in 2 (0.9%) samples and N.gonorrhoeae in 1 (0.5%) sample by PCR. In this study, 95.3% of the patients were married and 96.7% had only one sexual partner in the mean time. The rate of detection of pathogens were statistically higher in women who have had two or more pregnancies (p<0.05). In our study, T.vaginalis together with N.gonorrhoeae and C.trachomatis were investigated by PCR method in women with vaginal discharge. The use of multiplex PCR test allowed simultaneous investigation of multiple pathogens in the patient samples.

[Evaluation of Enzyme Immunoassay (EIA), Immunoblot and HIV RNA Polymerase Chain Reaction Test Results in the Diagnosis of Human Immunodeficiency Virus (HIV) Infection]

Acquired Immunodeficiency syndrome (AIDS) is an important global public health issue. Increasing HIV/AIDS cases reported each year has become a serious health problem for our country. The fourth generation enzyme immunoassay (EIA) test is the first step in the laboratory diagnosis of human immunodeficiency virus (HIV) infection. When the EIA test is repeatedly reactive, antibody-based tests such as immuno blot (IB), line immunoassay (LIA), HIV 1-2 antibody differentiation immunoassay, and HIV RNA tests for the early period of infection are used as confirmatory tests. The aim of this study was to evaluate the results of three different methods for the diagnosis of HIV infection. HIV 1-2 IB and quantitative HIV-1 RNA PCR tests were performed in 199 patient samples. These samples were detected as the reactive or gray zone with HIV 1-2 Ab+Ag EIA test between 2010 and 2015 at Akdeniz University Hospital, Microbiology Laboratory. HIV 1-2 Ab+Ag determination in serum samples was performed with the EIA method (Elecsys HIV combi PT test, Roche Diagnostics, Germany). A commercial kit (INNO-LIA HIV I-II Score, Innogenetics, Belgium) was used for HIV 1-2 IB method. The presence of HIV-1 RNA was investigated by automated nucleic acid extraction and real-time PCR method (Ampliprep/COBAS Tagman HIV-1 Test, Roche Diagnostics, Germany) in plasma samples. For statistical analysis, SPSS, Mann Whitney U test was used, ROC analysis was performed and p<0.05 value was considered statistically significant. HIV 1-2 Ab+Ag EIA COI (cut-off index) median value was higher with positive HIV 1-2 IB and HIV-1 RNA results than negative HIV 1-2 IB and HIV-1 RNA results. These values were 394 (range: 11.5-2272) and 1.79 (range: 1.01-83.3) respectively and this difference was statistically significant (p< 0.001). HIV-1 RNA test results were positive in one patient with gray zone and two patients with negative HIV 1-2 IB result (viral loads were > 10.000.000, > 10.000.000 and 5.040.000 copies/ml, respectively). For the kit that we used for HIV 1-2 Ab+Ag EIA COI ratio of >16.45 had a sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of 97.6%, 98.1%, 97.6% and 98.1%, respectively for the detection of HIV infection (r= 0.994, p< 0.001). HIV 1-2 Ab+Ag EIA S/CO ratio of < 9.26 had a sensitivity, specificity, PPV and NPV of 100%, 92.5%, 91.1% and 100% (p< 0.001). HIV infection is diagnosed if HIV 1-2 Ab+Ag EIA test result is repeatedly reactive and HIV 1-2 IB test and HIV-1 RNA tests are positive. In our study, HIV 1-2 Ab+Ag EIA COI median value was 394 (range: 11.5-2272) in this group of patients (p< 0.001). HIV-1 RNA PCR test was positive in three patients with > 10.000.000, 5.040.000 and > 10.000.000 copies/ml whose EIA tests were repeatedly reactive. HIV IB test was detected as the gray zone in one of them and as negative in the remaining two (HIV EIA S/CO values were 265, 9.5 and 131.8, respectively). These patients were diagnosed as acute HIV infection with clinical and laboratory findings. In conclusion, HIV RNA should also be performed and included in the diagnostic algorithm for acute HIV infection.

[Evaluation of the BD Phoenix100 System and Colistin Broth Disk Elution Method for Antimicrobial Susceptibility Testing of Colistin Against Gram-negative Bacteria]

Infections with multidrug resistant gram-negative bacteria is a growing problem especially in health care settings. Colistin is one of the last resort antibiotics for such infections in which treatment options are limited. Increasing resistance to colistin is a global problem. Clinical and Laboratory Standards Institute (CLSI) and the European Committee on Antimicrobial Susceptibility Testing (EUCAST) study groups have recommended the ISO-standard broth microdilution method (20776-1) as the reference method for the determination of colistin susceptibility. Since the broth microdilution method is not a practical method, it is rarely used in routine clinical microbiology laboratories, yet simple and accurate phenotypic detection methods for the determination of colistin resistance in routine microbiology laboratories are not precisely defined. The aim of this study was to evaluate BD Phoenix100 (Becton Dickinson, USA) system and colistin broth disk elution method for the detection of in vitro activity of colistin against gram-negative bacteria. A total of 419 gram-negative bacteria, including 199 Klebsiella pneumoniae, 163 Acinetobacter baumannii, 34 Escherichia coli, 20 Enterobacter spp., and three Citrobacter spp. isolates which were isolated from various clinical samples in our hospital between 2016-2018 were tested. The broth microdilution method was used as the reference method applying ISO-standard broth microdilution methods (20776-1) and CLSI/EUCAST recommendations. For colistin broth disk elution method, final concentrations of 0 (growth control), 1, 2 and 4 μg/ml were obtained by adding 10 μg colistin disks to four tubes containing 10 ml cation-adjusted Mueller Hinton broth per isolate. After incubation at room temperature for 30 minutes, 50 μl of standardized inoculum suspensions were added to the tubes. Colistin minimum inhibitor concentration (MIC) values were read visually after 16-20 hours of incubation at 35°C in ambient air. Manufacturer's recommendations were followed for BD Phoenix100 system. The categorical agreement between the reference broth microdilution method and the colistin broth disk elution method was 99.3%, very major error and major error rates were 0.2% and 0.5%, respectively. For BD Phoenix100 system, the categorical agreement was 95%, with a very major error rate of 5%. Our results showed that colistin broth disc elution method worked well compared to the reference broth microdilution method. The BD Phoenix100 system, with a high very major error rate, does not reliably distinguish colistin-resistant and colistin-susceptible strains.

[Determination of cytomegalovirus glycoprotein B genotypes in different geographical regions and different patient groups in Turkey]

Cytomegalovirus (CMV), a common virus found all around the world, usually causes asymptomatic infections in immunocompetent hosts, however it may lead to serious complications in immunodeficient patients and in the fetus. CMV is divided into four genotypes according to the polymorphisms in UL55 gene that encodes for envelope glycoprotein B. Nucleotide polymorphisms of CMV gB gene can affect the cell tropism of the virus and host immune response and believed to have important changes in the pathogenesis of CMV. The aim of this study was to determine the gB genotypes of CMV isolates from different patient groups selected from different regions of Turkey. A total of 136 clinical specimens from patients (66 female, 70 male; age range: 0-65 years, mean age: 24.03 ± 17.17) who were diagnosed to have CMV infection by polymerase chain reaction (PCR) and/or antigenemia tests, between 2001-2014, in the medical school hospitals of Akdeniz, Ege, Istanbul Cerrahpasa and Erciyes Universities (located at Mediterranean, Aegean, northwest and central Anatolia regions, respectively), were included in the study. The patient group consisted of 80 renal transplant (RT) recipients, 35 stem cell transplant (SCT) recipients, 13 newborns, seven heart transplant (HT) recipients and one pregnant woman. CMV gB genotypes were determined by PCR-RFLP (restriction fragment length polymorphism) method, and DNA sequencing and phylogenetic analysis were performed for the randomly selected 15 isolates with different genotypes. Among 136 (135 plasma, 1 amnion fluid) samples, the most frequent genotype was gB1 (n= 44, 32.4%), followed by gB2 (n= 39, 28.6%), gB3 (n= 36, 26.5%) and gB4 (n= 8, 5.9%); however nine (6.6%) samples could not be genotyped. When analysis were interpreted according to the patient groups, it was determined that the genotypes in RT recipients were gB1 32.3%, gB2 28.7%, gB3 26.5% and gB4 5.9%; in SCT recipients gB1 34.3%, gB2 28.6%, gB3 22.9% and gB4 5.7%; in HT recipients gB3 57.1%, gB1 14.3% and gB2 14.3%; in newborns gB1 38.4%, gB3 30.8%, gB2 15.4% and gB4 7.7%, and gB2 genotype in the pregnant woman. As our study was a descriptive study to determine the genotypes of CMV gB, the relationship between the genotypes and the variants such as viral load, symptomatic disease and prognosis were not analyzed. As a result, the isolation of different gB genotypes in various case groups from four distinctive provinces, underlines the diversity of CMV gB genotypes in Turkey.

The Frequency of Pneumocystis carinii in Patients with Haematologic Malignancies and Pneumonia

Pneumocystis carinii (P. carinii) is an organism which was previously considered as a protozoan but recently it was shown to be more related to fungi. P. carinii increasingly causes opportunistic infections in immunocompromised patients. In this study, we detected P. carinii oocysts by indirect immunofluorescence test in 33 specimens obtained from 31 patients with haematological malignancies who had symptoms of pneumonia and investigated probable risk factors (corticosteroid usage, neutropenia duration, severe or mild neutropenia and type of haematological malignancy) for P. carinii pneumonia in P. carinii (+) patients. Although not statistically significant, PCP incidence was higher in relapsed acute leukemia (AL) patients (62.5%), patients with prolonged neutropenia (57.1%), and who received high dose ARA-C therapy (62.5%). P. carinii (+) patients were treated with trimethoprim-sulfamethoxazole. Six patients with PCP did not respond to therapy and died (50%). In conclusion PCP is not infrequent in AL (especially relapsed AL) and, indirectly we can suggest that chemoprophylaxis may be considered for these patients when they were in severe and prolonged neutropenia after high dose ARA-C therapy.