Secondary bacterial infections and antimicrobial resistance in COVID-19: comparative evaluation of pre-pandemic and pandemic-era, a retrospective single center study.

PURPOSE: In this study, we aimed to evaluate the epidemiology and antimicrobial resistance (AMR) patterns of bacterial pathogens in COVID-19 patients and to compare the results with control groups from the pre-pandemic and pandemic era. METHODS: Microbiological database records of all the COVID-19 diagnosed patients in the Ege University Hospital between March 15, 2020, and June 15, 2020, evaluated retrospectively. Patients who acquired secondary bacterial infections (SBIs) and bacterial co-infections were analyzed. Etiology and AMR data of the bacterial infections were collected. Results were also compared to control groups from pre-pandemic and pandemic era data. RESULTS: In total, 4859 positive culture results from 3532 patients were analyzed. Fifty-two (3.59%) patients had 78 SBIs and 38 (2.62%) patients had 45 bacterial co-infections among 1447 COVID-19 patients. 22/85 (25.88%) patients died who had bacterial infections. The respiratory culture-positive sample rate was 39.02% among all culture-positive samples in the COVID-19 group. There was a significant decrease in extended-spectrum beta-lactamase (ESBL)-producing Enterobacterales (8.94%) compared to samples from the pre-pandemic (20.76%) and pandemic era (20.74%) (p = 0.001 for both comparisons). Interestingly, Acinetobacter baumannii was the main pathogen in the respiratory infections of COVID-19 patients (9.76%) and the rate was significantly higher than pre-pandemic (3.49%, p < 0.002) and pandemic era control groups (3.11%, p < 0.001). CONCLUSION: Due to the low frequency of SBIs reported during the ongoing pandemic, a more careful and targeted antimicrobial prescription should be taken. While patients with COVID-19 had lower levels of ESBL-producing Enterobacterales, the frequency of multidrug-resistant (MDR) A. baumannii is higher.

Evaluation and follow-up of antibody formation after CoronaVac vaccine.

OBJECTIVE: The aim of this study was to monitor the time-dependent change by evaluating the antibody levels at the 4th, 7th, 10th, 13th, and 16th weeks after the second dose of the CoronaVac vaccine. METHODS: The study group (n=65) were between 21 and 60 years old and received two doses of the CoronaVac vaccine. Blood samples were collected after 4th, 7th, 10th, 13th, and 16th weeks of the second dose of the vaccine administration. There was a coronavirus disease 2019 recovered group (n=29) who were SARS-CoV-2 real-time PCR test result positive before the vaccination period, and no coronavirus disease 2019 history group (n=36). Age, BMI, gender, smoking, comorbidity, coronavirus disease 2019 contact history, and working in the coronavirus disease 2019 service history of the individuals were recorded. RESULTS: No statistically significant difference was found in the descriptive findings of the individuals according to coronavirus disease 2019 recovered group and no coronavirus disease 2019 history group. It was observed that antibody levels in the coronavirus disease 2019 recovered group were found to be higher for each period of serum collection compared to the no coronavirus disease 2019 history group, which were statistically significant. The distribution curves of the antibody levels according to the timing of blood collection in coronavirus disease 2019 recovered group, no coronavirus disease 2019 history group, and total subjects were extrapolated, and it was observed that the estimated time for the antibodies to reach the threshold value of the test was 214, 145, and 166 days after vaccination. CONCLUSION: It is important to make booster doses, as the CoronaVac vaccine will lose its effect after the fifth month due to the decrease in Ab levels. In addition, since the antibody levels decrease later in those who have a history of coronavirus disease 2019 infection and are vaccinated, individuals who have no previous history of coronavirus disease 2019 should be given priority for vaccination.

Carbapenemase investigation with rapid phenotypic test (RESIST-4 O.K.N.V) and comparison with PCR in carbapenem-resistant Enterobacterales strains.

Background and Objectives: RESIST-4 O.K.N.V. assay is a lateral immunochromatocraphic test for the identification of oxacillinase (OXA)-48-like, Klebsiella pneumoniae carbapenemase (KPC), New Delhi metallo-ß-lactamase (NDM), and Verona integron-encoded metallo-ß-lactamase (VIM) producing strains. It was aimed to evaluate the performance of the RESIST-4 O.K.N.V. test and to compare it with the reference method polymerase chain reaction (PCR). Also, the objective was to determine the distribution of carbapenemase types of CRE strains isolated in our hospital. Materials and Methods: Between January 2016-October 2019, 187 strains isolated from clinical samples were included in this study. Bacterial identification was done using MALDI-TOF MS. Antibiotic susceptibility tests were studied with the VITEK-2 automated system. Meropenem minimum inhibitory concentrations (MICs) were determined by the gradient test. All strains were studied with the RESIST-4 O.K.N.V. test and then the strains were selected for the PCR test. bla OXA-48, bla NDM, bla KPC, and bla VIM were investigated with PCR. K. pneumoniae NCTC® 13438 (KWIKSTIKTM, Microbiologics®, USA) was used as the positive control, E. coli ATTC® 25922 TM (Microbiologics®, USA) and three carbapenem-sensitive clinical isolates were also used as the negative control. Results: Meropenem MIC50 and MIC90 values were determined to be >32 mg/L. With PCR bla OXA-48, bla NDM, bla KPC and bla VIM were detected in 79, 63, 20, and 4 strains, respectively. bla OXA-48 and bla NDM were found together in 51 of the isolates. bla OXA-48, bla NDM, bla KPC, and bla VIM were not detected in two strains with carbapenem resistance in susceptibility tests. The sensitivity of the immunochromatographic test was 100% for OXA-48, KPC, and VIM but 84.1% for NDM. Specificity was determined as 100% for OXA-48, NDM, KPC, and VIM. Conclusion: RESIST-4 O.K.N.V. test showed high sensitivity and specificity in detecting OXA-48, KPC, NDM, and VIM type carbapenemases. However, it should be kept in mind that there may be false-negative results related to NDM.

Investigation of Toxoplasma gondii Seropositivity in Pregnant Women in Kastamonu Province, Turkey

Objective: Toxoplasma gondii (T. gondii) is a protozoan parasite that infects most warm-blooded animal species and causes toxoplasmosis. Especially infections that occur during pregnancy can lead to serious clinical symptoms. This study retrospectively revealed the T. gondii seroprevalence of pregnant women in Kastamonu province, Turkey. Methods: Anti-T. gondii IgM and IgG positivity of 1.294 pregnant women between the ages of 15-44 years who applied to the Obstetrics and Gynecology Outpatients of Kastamonu Training and Research Hospital from January 2018 to January 2022 were investigated retrospectively. The IgG avidity test was performed for both anti-T. gondii IgM and IgG positivity. Results: Anti-T. gondii IgM and IgG seropositivity were determined as 1.1% (n=14) and 20.3% (n=263), respectively. Anti-T. gondii IgM and IgG positivity were detected together in 11 pregnant women. IgG avidity test results of only six pregnant women could be reached, two pregnant had high IgG avidity, and four pregnant had low IgG avidity. Anti-T. gondii IgG positivity rate increased with increasing age (p=0.039). Conclusion: The number of seronegative pregnant women was considered high in Kastamonu. It is significant for expectant mothers to know about prevention methods in order not to acquire toxoplasmosis.

Investigation of the presence of carbapenemases in carbapenem-resistant Klebsiella pneumoniae strains by MALDI-TOF MS (matrix-assisted laser desorption ionization-time of flight mass spectrometry) and comparison with real-time PCR method.

PURPOSE: We aimed to develop a new procedure for rapid detection of the carbapenemase activity using MALDI-TOF MS, and to determine the sensitivity and specificity of the method. Also, we aimed to determine the distribution of carbapenemase genes among the K.pneumoniae strains isolated in our hospital using real-time PCR. METHOD: Between January 2017-February 2019; K. pneumoniae strains(n = 74) isolated from blood culture samples were included. Klebsiella pneumoniae NCTC 13438 was used as a positive control and Escherichia coli ATCC 25922 as a negative control. First, Imipenem, meropenem, and ertapenem MIC values of strains were determined. Then blaKPC, blaOXA-48, and/or blaNDM genes were investigated with PCR. Carbapenemase activity was investigated in strains with the newly developed method using MALDI-TOF MS. The performance of the new method was evaluated for both the second and fourth hours of the incubation period. RESULTS: While 65 strains were found resistant to tested carbapenems, nine of them were susceptible. Of the 65 resistant strains, 57 had blaOXA-48, 15 had blaNDM, and four had blaKPC genes. BlaOXA-48 and blaNDM genes were detected together in 11 strains. BlaOXA-48, blaNDM, and blaKPC genes were not detected in any of the susceptible strains. The sensitivity and specificity of MALDI-TOF MS at the second hour were 83.1% and 100%, respectively. At the fourth hour, the sensitivity and specificity of MALDI-TOF MS were 100%. No false-positive results were observed. CONCLUSION: The sensitivity of the method at the fourth hour was better than the second hour. The false-negative results observed in the second hour disappeared when the incubation period was extended to 4 h. MALDI-TOF MS which is still under development is a fast, cost-effective, promising method for the detection of carbapenemase activity.

Evaluation of the performance of QuantiFERON®-TB Gold plus test in active tuberculosis patients.

The aim was to evaluate the sensitivity and the possible factors affecting the sensitivity of the QuantiFERON®-TB Gold Plus (QFT-Plus) assay in culture-positive active TB (Tuberculosis) patients, to investigate the possible causes of negative and indeterminate results in active TB patients, and to compare the QFT-Plus results of active TB patients and latent tuberculosis infection (LTBI) cases. The QFT-Plus assay was performed in 46 active TB patients and 64 LTBI. The sensitivity of the test was found as 79.5% in all culture-positive patients, 72.7% in the immunocompromised patients, and 86.4% in the non-immunocompromised patients. Compared to active TB, individuals with LTBI had a lower T-cell response and lower IFN-É£ concentrations. It was determined that the immunocompromisation reduced the sensitivity of the test and the secreted IFN-É£ concentrations and increased the indeterminate results in patients with active TB. There was no difference in secreted IFN-É£ concentrations between M. tuberculosis clones, but higher IFN-É£ concentrations in patients infected with M. tuberculosis strains compared to patients infected with zoonotic strains. Compared with active TB, response to "only to TB2" was significantly higher in LTBI. In conclusion, it was concluded that TB2 tube increased sensitivity in LTBI but may not contribute to sensitivity in active TB.

Evaluation and follow-up of antibody formation after CoronaVac vaccine

SUMMARY OBJECTIVE: The aim of this study was to monitor the time-dependent change by evaluating the antibody levels at the 4th, 7th, 10th, 13th, and 16th weeks after the second dose of the CoronaVac vaccine. METHODS: The study group (n=65) were between 21 and 60 years old and received two doses of the CoronaVac vaccine. Blood samples were collected after 4th, 7th, 10th, 13th, and 16th weeks of the second dose of the vaccine administration. There was a coronavirus disease 2019 recovered group (n=29) who were SARS-CoV-2 real-time PCR test result positive before the vaccination period, and no coronavirus disease 2019 history group (n=36). Age, BMI, gender, smoking, comorbidity, coronavirus disease 2019 contact history, and working in the coronavirus disease 2019 service history of the individuals were recorded. RESULTS: No statistically significant difference was found in the descriptive findings of the individuals according to coronavirus disease 2019 recovered group and no coronavirus disease 2019 history group. It was observed that antibody levels in the coronavirus disease 2019 recovered group were found to be higher for each period of serum collection compared to the no coronavirus disease 2019 history group, which were statistically significant. The distribution curves of the antibody levels according to the timing of blood collection in coronavirus disease 2019 recovered group, no coronavirus disease 2019 history group, and total subjects were extrapolated, and it was observed that the estimated time for the antibodies to reach the threshold value of the test was 214, 145, and 166 days after vaccination. CONCLUSION: It is important to make booster doses, as the CoronaVac vaccine will lose its effect after the fifth month due to the decrease in Ab levels. In addition, since the antibody levels decrease later in those who have a history of coronavirus disease 2019 infection and are vaccinated, individuals who have no previous history of coronavirus disease 2019 should be given priority for vaccination.