The long-term impact of an antimicrobial stewardship program in febrile neutropenia: an 8 years follow up.

PURPOSE: To describe the long-term effects of an ASP among febrile neutropenia (FN) patients. METHODS: A quasi-experimental study was conducted between 2015 and 2023 at a tertiary care hospital in Istanbul, Türkiye. The ASP was implemented for FN patients, and the effects were assessed before and after the ASP interventions, which included FN clinical pathways and regular multi-disciplinary meetings with relevant healthcare workers. RESULTS: A total of 489 FN episodes of 290 patients were included, 42% were female, and the mean age was 56 years (SD: 15, range: 18-89 years). After the intervention, the rate of appropriate antimicrobial therapy at the levels of starting (p = 0.005), switching (p < 0.001), and de-escalation/discontinuation, (p < 0.001) significantly increased. Another positive impact of the ASP was a significant reduction in candidemia (from 4.88 to 0.74, p = 0.004), as well as a significant reduction in the 90-day mortality rate (from 19 to 5%, p < 0.001). In multivariate analysis, having a gram-negative bloodstream infection, prolonged days with fever, and a high risk for neutropenia were found to be significant predictors of 90-day mortality, while follow-up with ASP significantly reduced mortality. CONCLUSION: Implementation of ASP led to reduced candidemia and LOS without increasing mortality, even in a country with a high rate of antimicrobial resistance. Implementation of sustainable ASP for FN patients is critical in combating antimicrobial resistance.

Effectiveness of tocilizumab in non-intubated cases with COVID-19: a systematic review and meta-analysis.

PURPOSE: Tocilizumab, a monoclonal IL-6 receptor blocker, is an effective agent for severe-to-critical cases of COVID-19; however, its target patients for the optimum use need to be detailed. We performed a systematic review and meta-analysis to define its effect among severely ill but non-intubated cases with COVID-19. METHODS: We searched PubMed, Scopus, Web of Science, MEDLINE, Cochrane Central Register of Controlled Trials (CENTRAL), Medrxiv, and Biorxiv until February 13, 2022, for non-intubated cases, and included randomized-controlled trials (RCT) based on bias assessment. The primary outcomes were the requirement of invasive mechanical ventilation and mortality. Random effect and fixed-effect models were used. The heterogeneity was measured using the χ2 and I2 statistics, with χ2 p ≤ 0.05 and I2 ≥ 50% indicating the presence of significant heterogeneity. We registered the study to the International Prospective Register of Systematic Reviews (PROSPERO) with the registration number CRD42021232575. RESULTS: Among 261 articles, 11 RCTs were included. The pooled analysis of the 11 RCTs demonstrated that the rate of mortality was significantly lower in the tocilizumab group than in the control group (20.0% and 24.2%, OR: 0.84, 95% CI 0.73-0.96, and heterogeneity I2 = 0%. p = 0.82.). The mechanical ventilation rate was lower in the tocilizumab group than the control group (27% vs 35.2%, OR: 0.76, 95% CI 0.67-0.86, and heterogeneity I2 = 6%. p = 0.39). CONCLUSION: Among non-intubated severe COVID-19 cases, tocilizumab reduces the risk of invasive mechanical ventilation and mortality compared to standard-of-care treatment.

Characteristics and outcomes of carbapenemase harbouring carbapenem-resistant Klebsiella spp. bloodstream infections: a multicentre prospective cohort study in an OXA-48 endemic setting.

A prospective, multicentre observational cohort study of carbapenem-resistant Klebsiella spp. (CRK) bloodstream infections was conducted in Turkey from June 2018 to June 2019. One hundred eighty-seven patients were recruited. Single OXA-48-like carbapenemases predominated (75%), followed by OXA-48-like/NDM coproducers (16%). OXA-232 constituted 31% of all OXA-48-like carbapenemases and was mainly carried on ST2096. Thirty-day mortality was 44% overall and 51% for ST2096. In the multivariate cox regression analysis, SOFA score and immunosuppression were significant predictors of 30-day mortality and ST2096 had a non-significant effect. All OXA-48-like producers remained susceptible to ceftazidime-avibactam.

Effectiveness of favipiravir in COVID-19: a live systematic review.

We performed a systematic review and meta-analysis for the effectiveness of Favipiravir on the fatality and the requirement of mechanical ventilation for the treatment of moderate to severe COVID-19 patients. We searched available literature and reported it by using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Until June 1, 2021, we searched PubMed, bioRxiv, medRxiv, ClinicalTrials.gov, Cochrane Central Register of Controlled Trials (CENTRAL), and Google Scholar by using the keywords "Favipiravir" and terms synonymous with COVID-19. Studies for Favipiravir treatment compared to standard of care among moderate and severe COVID-19 patients were included. Risk of bias assessment was performed using Revised Cochrane risk of bias tool for randomized trials (RoB 2) and ROBINS-I assessment tool for non-randomized studies. We defined the outcome measures as fatality and requirement for mechanical ventilation. A total of 2702 studies were identified and 12 clinical trials with 1636 patients were analyzed. Nine out of 12 studies were randomized controlled trials. Among the randomized studies, one study has low risk of bias, six studies have moderate risk of bias, and 2 studies have high risk of bias. Observational studies were identified as having moderate risk of bias and non-randomized study was found to have serious risk of bias. Our meta-analysis did not reveal any significant difference between the intervention and the comparator on fatality rate (OR 1.11, 95% CI 0.64-1.94) and mechanical ventilation requirement (OR 0.50, 95% CI 0.13-1.95). There is no significant difference in fatality rate and mechanical ventilation requirement between Favipiravir treatment and the standard of care in moderate and severe COVID-19 patients.

Changes in antimicrobial resistance and outcomes of health care-associated infections.

To describe the change in the epidemiology of health care-associated infections (HAI), resistance and predictors of fatality we conducted a nationwide study in 24 hospitals between 2015 and 2018. The 30-day fatality rate was 22% in 2015 and increased to 25% in 2018. In BSI, a significant increasing trend was observed for Candida and Enterococcus. The highest rate of 30-day fatality was detected among the patients with pneumonia (32%). In pneumonia, Pseudomonas infections increased in 2018. Colistin resistance increased and significantly associated with 30-day fatality in Pseudomonas infections. Among S. aureus methicillin, resistance increased from 31 to 41%.

Human metapneumovirus infection: Diagnostic impact of radiologic imaging.

BACKGROUND: Human metapneumovirus (hMPV) is a recently detected virus, which can cause mild to severe respiratory tract infections. Through this study, we aimed to detail the outcomes of hMPV infections. MATERIALS/METHODS: Between January 2012 and November 2017, patients who had hMPV detected in nasopharyngeal or bronchoalveolar lavage by molecular respiratory pathogen tests were evaluated. The Food and Drug Administration cleared multiplexed-polymerase chain reaction system (Idaho Technology, Salt Lake City, UT) was used for diagnosis. Chest radiography (CR) and computed tomography (CT) were evaluated by an expert radiologist. RESULTS: In total 100 patients were included, the mean age was 22.9 (0-87) years, and 50% were male. The hospitalization rate was 52%. Lower respiratory system infection (LRTI) was diagnosed in 44 patients with clinical findings, and in 31 patients out of 44 the radiological findings supported the diagnosis. The LRTI rate was significantly higher in adults than children (66.7%-32.8%; P = 0.001). In CR, peribronchovascular infiltration (PI) was the most common feature seen in 14 out of 18 patients and was generally bilateral (13 out of 18 patients). In CT imaging, ground-glass opacity was the most common finding seen in 11 out of 16 patients and nodular consolidation in five patients. Ribavirin was given to four patients, three of whom were severe and required respiratory support. None of the patients died of hMPV infection. CONCLUSIONS: The ground-glass opacity in CT was similar to other respiratory virus infections, and PI in CR was very common and typical; however, nodular consolidation that may mimic bacterial infection was seen in one-fourth of CT.

Systematic Review and Meta-analysis of Postexposure Prophylaxis for Crimean-Congo Hemorrhagic Fever Virus among Healthcare Workers.

We performed a systematic review and meta-analysis on the effectiveness of ribavirin use for the prevention of infection and death of healthcare workers exposed to patients with Crimean-Congo hemorrhagic fever virus (CCHFV) infection. Splashes with blood or bodily fluids (odds ratio [OR] 4.2), being a nurse or physician (OR 2.1), and treating patients who died from CCHFV infection (OR 3.8) were associated with healthcare workers acquiring CCHFV infection; 7% of the workers who received postexposure prophylaxis (PEP) with ribavirin and 89% of those who did not became infected. PEP with ribavirin reduced the odds of infection (OR 0.01, 95% CI 0-0.03), and ribavirin use <48 hours after symptom onset reduced the odds of death (OR 0.03, 95% CI 0-0.58). The odds of death increased 2.4-fold every day without ribavirin treatment. Ribavirin should be recommended as PEP and early treatment for workers at medium-to-high risk for CCHFV infection.

Rapid Molecular Detection of Gastrointestinal Pathogens and Its Role in Antimicrobial Stewardship.

We aimed to detect the etiological agents of acute diarrhea by a molecular gastrointestinal pathogen test (MGPT) and to assess the impact of MGPT on antimicrobial stewardship programs (ASP). This is a prospective observational study and was conducted between 1 January 2015 and 30 June 2017. We included consequent patients who had acute diarrhea. At the end of 2015, we implemented ASP in acute diarrhea cases and compared the outcomes in the pre-ASP and post-ASP periods. An FDA-cleared multiplexed gastrointestinal PCR panel system, the BioFire FilmArray (Idaho Technology, Salt Lake City, UT), which detects 20 pathogens in stool, was used. In 499 out of 699 patients (71%), at least one pathogen was detected. Among 314 adults with positive MGPT, 101 (32%) enteropathogenic Escherichia coli (EPEC), 71 (23%) enteroaggregative E. coli (EAEC), 68 (22%) enterotoxigenic E. coli (ETEC), 55 (18%) Shiga toxin-producing E. coli (STEC) (17%) Norovirus, 48 (15%) Campylobacter, 21 (7%) Salmonella, and 20 (6%) Clostridium difficile strains were detected. Among 185 children, 55 (30%) EPEC, 37 (20%) C. difficile, 32 (17%) Norovirus, 29 (16%) EAEC, 22 (12%) STEC, 21 (11%) ETEC, 21 (11%) Campylobacter, 20 (11%) Salmonella, and 16 (5%) Rotavirus strains were detected. Inappropriate antibiotic use decreased in the post-ASP period compared with the pre-ASP period among inpatients (42.9% and 25.8%, respectively; P = 0.023). Using MGPT in clinical practice significantly decreased the unnecessary use of antibiotics. Detection of high rates of C. difficile in children and Salmonella spp., as well as relatively high rates of Campylobacter spp., which were hard to isolate by routine stool culture, were remarkable.

The rapid diagnosis of viral respiratory tract infections and its impact on antimicrobial stewardship programs.

We aimed to describe the potential benefit of new rapid molecular respiratory tests (MRT) in decreasing inappropriate antibiotic use among the inpatients presenting with influenza-like illness (ILI). We included patients from inpatient and outpatient departments who had ILI and performed MRT between 1 January 2015 and 31 December 2016 in a 265-bed private hospital in Istanbul. At the end of 2015, we implemented antimicrobial stewardship including systematic use of MRT. Then, we compared our observations between the year 2015 and the year 2016. We designed the study according to the STrengthening the Reporting of OBservational studies in Epidemiology (STROBE) tool. A U.S. Food and Drug Administration (FDA)-cleared multiplexed polymerase chain reaction (PCR) system (BioFire FilmArray, Idaho Technology, Salt Lake City, UT) which detects 17 viruses and three bacteria was used for diagnosis. In total, 1317 patients were included; 630 (48%) were inpatients and 569 (43%) were older than 16 years of age. At least one virus was detected in 747 (57%) patients. Rhinovirus/enterovirus, influenza virus, and adenovirus were the most commonly detected. Among hospitalized patients, in children, a significant decrease in antibiotic use (44.5% in 2015 and 28.8% in 2016, p = 0.009) was observed, but in adults, the decrease was not statistically significant (72% in 2015 and 63% in 2016, p = 0.36). The duration of antibiotic use after the detection of virus was significantly decreased in both children and adults (p < 0.001 and p = 0.007, respectively). By using MRT, inappropriate antibiotic use and, also, duration of inappropriate antibiotic use after the detection of virus was significantly decreased. It is time to increase the awareness about the viral etiology in respiratory tract infections (RTIs) and implement MRT in clinical practice.

The Practice of Antimicrobial Stewardship in Thoracic Surgery and its Effectiveness.

This study examines the effects of the bundle of antimicrobial stewardship measures for prophylactic antibiotics among thoracic surgery patients. A local protocol, based on current guidelines starting from December 2014, was developed by the Infection Control and Thoracic Surgery Teams. The effects of this protocol were assessed by monitoring a total of 1380 patients before and after its implementation from January 1, 2011, to December 31, 2022.

Discrepancy between IDSA and ESGBOR in Lyme disease: Individual participant meta-analysis in Türkiye.

BACKGROUND: The evidence on the prevalence of Lyme borreliosis (LB) is limited, but there is a suspicion of overdiagnosis of LB in recent years. We reviewed the LB diagnosis and treatment-related data in Türkiye, based on the Infectious Diseases Society of America (IDSA) 2020 and European Society of Clinical Microbiology and Infectious Diseases Study Group for Lyme Borreliosis (ESGBOR) 2018 guidelines. By detecting the disagreements between these two, we outlined the areas to be improved for future guidelines. METHODS: We performed a literature search according to the PRISMA guidelines in PubMed, Ovid-Medline, Web of Science, Turkish Medline, Scopus, CINAHL, ULAKBIM TR Index, Google Scholar and Cochrane Library databases. We included the published cases in a database and evaluated according to IDSA and ESGBOR guidelines. We outlined the reasons for misdiagnoses and inappropriate uses of antibiotics. RESULTS: We included 42 relevant studies with 84 LB cases reported from Türkiye between 1990 and December 2022. Among 84 cases, the most common clinical findings were nervous system findings (n = 37, 44.0%), erythema migrans (n = 29, 34.5%) and ophthalmologic findings (n = 15, 17.9%). The IDSA 2020 and ESGBOR 2018 guidelines agreed on the diagnosis of 71 (84.5%) cases; there was an agreement that 31 cases (36.9%) were misdiagnosed and 40 cases (47.6%) were correctly diagnosed, and there was disagreement for 13 cases (15.5%). Serum immunoglobulin M (IgM), IgG measurements by ELISA and western blot were widely performed, and they were effective in definitive diagnosis merely when used according to guidelines. Inappropriate use of antibiotics was detected in 42 (50.0%) of cases which were classified in the following categories: incorrect LB diagnosis, inappropriate choice of antibiotic, inappropriate route of drug administration and prolonged antibiotic treatment. CONCLUSION: Overdiagnosis and non-adherence to guidelines is a common problem. The discordance between seroprevalence and clinical studies necessitates a consensus over the best clinical approach.

Resensitization to colistin results in rapid and stable recovery of adherence, serum resistance and ompW in Acinetobacter baumannii.

BACKGROUND: Colistin resistance in Acinetobacter baumannii is an emerging problem that limits antimicrobial therapy options. MATERIALS & METHODS: We isolated two pairs of colistin susceptible and colistin-resistant A. baumannii (K1007/K1006 and K408/K409) from two patients diagnosed with carbapenem-resistant A. baumannii infection. Colistin susceptible isolates were exposed to in vitro colistin induction for 50 generations. The selected cell populations were subjected to DNA and RNA sequencing and phenotypic assays. RESULTS: In the in vitro induction assay, K408 gained colistin resistance on the corresponding day of clinical resistance (K408-G25) and got resensitized to colistin in the consecutive generation (K408-G26). A significant upregulation of ompW, ata, adeFGH genes on K408-G25 was followed by a downregulation upon resensitization to colistin (G26). Despite the upregulation of the ompW gene in transcriptomic analysis, the ompW protein disappeared on K408-G25 and recovered in the resensitized generation (G26). In parallel, disrupted cell membrane integrity recovered in K408-G26. In the K408-G25, downregulation of pbpG and upregulation of pbp1a/pbp3 genes decreased serum-resistance which was reversed in the resensitized generation (G26). The K1007 did not gain colistin resistance amongst 50-generations, however, the generation corresponding to clinical resistance day (K1007-G9) had a similar trend with K408-G25. The clinical colistin-resistant K409 and K1006 had SNPs on pmrA and pmrB genes. CONCLUSION: In this study, we observed that A. baumannii regulates adhesion, efflux pumps and serum-resistance associated genes as an early response to colistin stress. Besides, the ompW protein disappears in the cell membrane of colistin resistant cells which recovers after resensitization to colistin. The lack of ompW protein in colistin-resistant cells should be taken into consideration for escape mutants in development of antivirulence vaccination or treatment options.

An international multicenter study comparing COVID-19 omicron outcomes in patients with hematological malignancies treated with obinutuzumab versus rituximab.

OBJECTIVES: Hematological malignancy (HM) patients treated with anti-CD20 monoclonal antibodies are at higher risk for severe COVID-19. A previous single-center study showed worse outcomes in patients treated with obinutuzumab compared to rituximab. We examined this hypothesis in a large international multicenter cohort. METHODS: We included HM patients from 15 centers, from five countries treated with anti-CD20, comparing those treated with obinutuzumab (O-G) to rituximab (R-G) between December 2021 and June 2022, when Omicron lineage was dominant. RESULTS: We collected data on 1048 patients. Within the R-G (n = 762, 73%), 191 (25%) contracted COVID-19 compared to 103 (36%) in the O-G. COVID-19 patients in the O-G were younger (61 ± 11.7 vs. 64 ± 14.5, p = 0.039), had more indolent HM diagnosis (aggressive lymphoma: 3.9% vs. 67.0%, p < 0.001), and most were on maintenance therapy at COVID-19 diagnosis (63.0% vs. 16.8%, p < 0.001). Severe-critical COVID-19 occurred in 31.1% of patients in the O-G and 22.5% in the R-G. In multivariable analysis, O-G had a 2.08-fold increased risk for severe-critical COVID-19 compared to R-G (95% CI 1.13-3.84), adjusted for Charlson comorbidity index, sex, and tixagevimab/cilgavimab (T-C) prophylaxis. Further analysis comparing O-G to R-G demonstrated increased hospitalizations (51.5% vs. 35.6% p = 0.008), ICU admissions (12.6% vs. 5.8%, p = 0.042), but the nonsignificant difference in COVID-19-related mortality (n = 10, 9.7% vs. n = 12, 6.3%, p = 0.293). CONCLUSIONS: Despite younger age and a more indolent HM diagnosis, patients receiving obinutuzumab had more severe COVID-19 outcomes than those receiving rituximab. Our findings underscore the need to evaluate the risk-benefit balance when considering obinutuzumab therapy for HM patients during respiratory viral outbreaks.

Challenges in Diagnosis and Treatment of Fasciola hepatica Infection.

A 57-year-old female patient presented with fever, nausea, vomiting, loss of appetite, and weight loss within the last two months. Ceftriaxone and metronidazole therapy was started upon discovery of a liver abscess but provided no benefit. Following the of abscess biopsy, the patient developed fever, itching, anemia, acute renal failure, hyperbilirubinemia, and eosinophilia that required intensive care unit (ICU) admission. The Fasciola hepatica antibodies were detected by enzyme-linked immunosorbent assay (ELISA). Triclabendazole was started, after which the symptoms and magnetic resonance imaging (MRI) findings regressed. Even without eosinophilia, F. hepatica should be considered in cases with a liver abscess that does not respond to antibiotics.

COVID-19 associated bacterial infections in intensive care unit: a case control study.

We described the secondary bacterial infections (SBI) among COVID-19 patients in comparison with non-COVID-19 patients. We performed a retrospective case-control study between January 01, 2020 and April 01, 2022. Including the adult patients, who stayed ≥ 72 h in intensive care unit (ICU). In total 405 patients were included, 135 had (33.3%) COVID-19, with similar age and gender. The length of stay in ICU was not different (11.4 vs 8.2, p = 0.109), however mean intubation days were higher among COVID-19 cases (6.5 vs 3.8, p = 0.005), SBI were more common among COVID-19 cases (34% vs 10.7%, p < 0.001). Among the patients with pneumonia, the rate of gram-positive bacteria was higher in COVID-19 group than the control group (39% vs 5%, p = 0.006). The predictors for SBI were having COVID-19 (OR: 2.3, Cl 1.25-4.32, p = 0.008), days of intubation (OR: 1.05, Cl 1.01-1.10, p = 0.004), and being male (OR: 2, Cl 1.12-3.58, p = 0.018). The predictors of mortality were COVID-19 (OR: 2.38, Cl 1.28-4.42, p = 0.006), days of intubation (OR: 1.06, Cl 1.03-1.09, p < 0.001), active hematologic malignancy (OR: 3.1, Cl: 1.33-7.28, p = 0.09), active solid tumors (OR: 2.44, Cl 1.21-4.91, p = 0.012), and coronary artery diseases (OR: 1.8, Cl 1.01-3.52, p = 0.045). The most common SBI in COVID-19 patients were methicillin-sensitive Staphylococcus aureus. No carbapenem-resistant Enterobacterales related infections were detected in COVID-19 patients.

The challenges in the monitoring of infectious diseases after the earthquake in Türkiye in 2023.

After the devastating earthquake in Türkiye and Syria in February, 2023, the long-term failure to meet the need for shelter, unfavourable living conditions in tent settlements, poor access to clean drinking water, water suitable for personal hygiene, and sanitary facilities, as well as interruptions in provision of primary health-care services, have emerged as the most important risk factors contributing to the spread of infectious diseases. 3 months after the earthquake, most of these problems persist in Türkiye. Data on the control of infectious diseases are scarce according to the reports prepared by medical specialist associations based on observations of health-care providers working in the region and statements made by the local health authorities. According to these unsystematised data, and considering the conditions in the region, faecal-oral transmissible gastrointestinal infections, as well as respiratory and vector-borne infections, are the main challenges. Vaccine-preventable diseases, such as measles, varicella, meningitis, and polio can be spread in temporary shelters due to interrupted vaccine services and crowded living conditions. In addition to controlling risk factors for infectious diseases, sharing data on the status and control of infectious diseases in the region with the community, health-care providers, and relevant expert groups should be a priority to improve the understanding of the effects of interventions and prepare for possible infectious disease outbreaks.

The Effect of Vaccination with Pfizer-BioNTech or CoronaVac on Disease Prognosis Among Hospitalized COVID-19 Patients.

Objective: The Turkish Ministry of Health offered two types of vaccines by January 13, 2021, which are CoronaVac (Sinovac Biotech, China) and Pfizer-BioNTech. We aimed to describe the impact of the CoronaVac and Pfizer-BioNTech vaccines on clinical outcomes among hospitalized patients during a six-month period. Methods: We included patients older than 18 years old and hospitalized because of COVID-19 when the vaccines were available. We conducted the study at Koç University Hospital and American Hospital between June 2021, six months after the vaccination started, and December 2021. Results: In total, 444 RT-PCR confirmed hospitalized patients were included. The mean age of the patients was 59 (standard deviation [SD]=18), and 42.8% were female. The most common comorbidity was hypertension (39%), followed by diabetes mellitus (27%), cardiovascular diseases (18.4%), chronic lung diseases (14.6%), cancer (9.2%), and chronic renal diseases (8%). In multivariate analysis, no vaccination (OR=4.7, CI=2.25-10.06; p<0.001), age >65 (OR=5.2, CI=2.25-11.98; p<0.001), cancer (OR=7.6, CI=3.04-19.31; p<0.001), and chronic kidney disease (OR=3.1, CI=1.14-8.74; p=0.026) significantly increased mortality in COVID-19 patients. Eighteen percent of patients were in the intensive care unit (ICU). One hundred eighty-one patients (40.8%) were non-vaccinated before their admission, and their mortality (17.6%) was higher compared to the patients who were vaccinated with at least one type of vaccine (p=0.002). None of the patients who received two doses of Pfizer-BioNTech vaccines died. Conclusion: Among the inpatients with COVID-19, the predictors for mortality were being unvaccinated, older age, cancer, chronic kidney disease, and cardiovascular diseases. Among the vaccinated inpatients, having two doses of the Pfizer-BioNTech vaccine was the only effective protective measure against mortality, and two doses of the CoronaVac vaccine had no significant effect in preventing fatality.

Duration of infectious shedding of SARS-CoV-2 Omicron variant and its relation with symptoms.

OBJECTIVES: SARS-CoV-2 infections with Omicron variants have a high capability of human-to-human transmission. Nevertheless, the duration of isolation for mild cases was shortened to 5 to 7 days. We aimed to detect the duration of viral shedding among healthcare workers (HCWs) with Omicron by using viral culture. METHODS: We prospectively included newly diagnosed nonsevere, symptomatic SARS-CoV-2 positive HCWs. Nasopharyngeal swab samples were obtained consecutively on days 5, 7,10, and 14 of onset of symptoms. The samples were examined by nucleic acid amplification test and viral culture. RESULTS: In total, 55 non-severe patients with SARS-CoV-2 Omicron variant were included. The mean age of the population was 34 years (range, 23 to 54) and 78% (43/55) were female. The PCR positivity rate on days 5, 7, 10, and 14 was 96.4% (53/55), 87.3% (48/55), 74.545% (41/55), and 41.8% (23/55) consecutively, whereas the viral culture positivity rates were 83% (44/53), 52% (26/50), 13.5% (7/52), and 8% (4/50). Among the patients who became symptom-free, the viral culture positivity rates were 100% (4/4), 58% (7/12), 11% (3/27), and 5% (2/41). DISCUSSION: We showed that among the SARS-CoV-2 Omicron variant infected patients, viral shedding continues for ≥10 days in 13.5% of all cases and 11% in symptom-free cases. The decision for cessation of isolation according to the presence of symptoms could be reconsidered until further studies disapprove of our results. Meanwhile, the infected HCWs who give care to high-risk patients for severe COVID-19 might extend their isolations ≤10 days after the onset of symptoms, regardless of their symptoms.