Search

Streptococcus vestibularis is a recently described member of the viridans group that was first isolated from the vestibular mucosa of the human oral cavity and described as a new species in 1988. It has been rarely associated with human infections. In few papers, it has been reported as a causal agent of systemic infection in immunosupressed adults and in those with other severe underlying diseases, like coronary valve diseases. A 65-year-old woman was admitted to the hospital with complaints of fever for three months, general malaise, effort dyspnea, weight loss, back pain and myalgia. Both native aortic valve endocarditis and spondylodiscitis due to Streptococcus vestibularis were detected. The patient was successfully treated with intravenous potassium penicillin G and gentamicin for six weeks, followed by oral amoxicillin for three months, in addition to aortic valve replacement. In all patients with spondylodiscitis, infective endocarditis should be considered, particularly in patients with heart valve disease history, since spondylodiscitis may be the presenting sign of an infective endocarditis. Cardiac valve replacement surgery should be performed if the course of fever and inflammatory syndrome is unfavorable after appropriate antibiotic treatment. We report the first case with both native aortic valve endocarditis and spondylodiscitis due to Streptococcus vestibularis. Keywords: endocarditis, spondylodiscitis, Streptococcus vestibularis

Streptococcus vestibularis is a recently described member of the viridans group that was first isolated from the vestibular mucosa of the human oral cavity and described as a new species in 1988. It has been rarely associated with human infections. In few papers, it has been reported as a causal agent of systemic infection in immunosupressed adults and in those with other severe underlying diseases, like coronary valve diseases. A 65-year-old woman was admitted to the hospital with complaints of fever for three months, general malaise, effort dyspnea, weight loss, back pain and myalgia. Both native aortic valve endocarditis and spondylodiscitis due to Streptococcus vestibularis were detected. The patient was successfully treated with intravenous potassium penicillin G and gentamicin for six weeks, followed by oral amoxicillin for three months, in addition to aortic valve replacement. In all patients with spondylodiscitis, infective endocarditis should be considered, particularly in patients with heart valve disease history, since spondylodiscitis may be the presenting sign of an infective endocarditis. Cardiac valve replacement surgery should be performed if the course of fever and inflammatory syndrome is unfavorable after appropriate antibiotic treatment. We report the first case with both native aortic valve endocarditis and spondylodiscitis due to Streptococcus vestibularis.

Scope: Despite the large availability of vaccines, coronavirus disease 2019 (COVID-19), induced by severe acute respiratory syndrome coronavirus 2, continues to be a major threat for health-care providers and fragile people. A number of options are now available for outpatients with mild-to-moderate COVID-19 at the risk of disease progression for the prevention of deaths or hospitalization., Methods: A European Society of Clinical Microbiology and Infectious Diseases COVID-19 guidelines task force was established by the European Society of Clinical Microbiology and Infectious Diseases Executive Committee. A small group was established, half appointed by the chair and the remaining selected based on an open call. Each panel met virtually once a week. For all decisions, a simple majority vote was used. A long list of clinical questions using the population, intervention, comparison, outcome format was developed at the beginning of the process. For each population, intervention, comparison, outcome, two panel members performed a literature search, with a third panelist involved in case of inconsistent results. Voting was based on the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach., Recommendations: In this update, we focus on anti-viral agents, monoclonal antibodies (mAbs) and other treatment options proposed for patients with mild or moderate COVID-19 who are at the risk of hospitalization or death. Although the use of anti-virals is recommended, especially nirmatrelvir/ritonavir and remdesivir or, alternatively, molnupirarvir, the administration of mAbs against the spike protein strictly depends on circulating variants or the ability to test timely for variants and sub-variants. At the time of writing (April-June 2022), the only active mAb was tixagevimab/cilgavimab given the predominance of the Omicron BA.2, BA.3, BA.4 and BA.5 sub-lineages in Europe. However, considering that the epidemiological scenario is extremely dynamic, constant monitoring of variants of concern is mandatory., (Copyright © 2022 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)

This study aimed to detect carbapenemase genes and to determine the in vitro susceptibility of Ceftazidime-Avibactam (CZA) in Enterobacterales isolates. Carbapenemase genes were detected by polymerase chain reaction. CZA sensitivity of isolates was evaluated with broth microdilution (BMD) and disk diffusion methods. A total of 318 carbapenem-resistant Enterobacterales isolates were included. Most of the isolates (n = 290, 91.2%) were identified as Klebsiella pneumoniae. The most common carbapenemase type was OXA-48 (n = 82, 27.6%). CZA susceptibility was evaluated in 84 isolates with OXA-48 and KPC carbapenemase activity. Both BMD and disk diffusion methods revealed that 95.2% of the isolates were sensitive to CZA; whereas, 4 (4.76%) isolates were resistant to CZA. Among colistin resistant isolates, 96.5% (n = 80) of them were susceptible to CZA. Our study demonstrated high in vitro efficacy of CZA in Enterobacterales isolates producing OXA-48 carbapenemase. High susceptibility rates against colistin resistant isolates which generally are also pan drug resistant, makes CZA a promising therapeutic choice for difficult-to-treat infections. Due to its high correlation with the BMD, disk diffusion method is a suitable and more practical method in detecting CZA in vitro activity.

Objectives: COVID-19 is a great threat to the modern world and significant threat to immunocompromised patients, including patients with chronic renal failure. We evaluated COVID-19 incidence among our hemodialysis patients and investigated the most probable immune mechanisms against COVID-19., Materials and Methods: Başkent University has 21 dialysis centers across Turkey, with 2420 patients on hemodialysis and 30 on peritoneal dialysis. Among these, we retrospectively evaluated 602 patients (257 female/345 male) with chronic renal failure receiving hemodialysis as renal replacement therapy; 7 patients (1.1%) were infected with SARS-CoV-2. We retrospectively collected patient demographic characteristics, clinical data, and immunological factors affecting the clinical course of the disease. We divided patients into groups and included 2 control groups (individuals with normal renal functions): group I included COVID-19-positive patients with normal renal function, group II included COVID-19-positive hemodialysis patients, group III included COVID-19-negative hemodialysis patients, and group IV included COVID-19-negative patients with normal renal function. Lymphocyte subsets in peripheral blood and typing of human leukocyte antigens were analyzed in all groups, with killer cell immunoglobulin like receptor genes analyzed only in COVID-19-positive patients and healthy controls., Results: No deaths occurred among the 7 COVID-19-positive hemodialysis patients. Group I patients were significantly older than patients in groups II and III (P = .039, P = .030, respectively) but not significantly different from group IV (P = .060). Absolute counts of natural killer cells in healthy controls were higherthan in other groups (but not significantly). ActivatedT cells were significantly increased in both COVID-19-positive groups versus COVID-19-negative groups. Groups showed significant differences in C and DQ loci with respect to distribution of alleles in both HLA classes., Conclusions: Although immunocompromised patients are at greater risk for COVID-19, we found lower COVID-19 incidence in our hemodialysis patients, which should be further investigated in in vitro and molecular studies.

Objectives: We aimed to describe the mechanisms of colistin resistance in Acinetobacter baumannii . Materials and Methods: Twenty-nine patients diagnosed with colistin-resistant A. baumannii infection were included to the study. The mutations in pmrCAB , lpxA , lpxC , and lpxD genes, expression of pmrCAB , carbapenemases, and mcr-1 positivity were studied. Results: Twenty-seven (93%) of the patients received IV colistin therapy during their stay, and the case fatality rate was 45%. All mutations in pmrC and pmrB were found to be accompanied with a mutation in lpxD . The most common mutations were I42V and L150F in pmrC (65%), E117K in lpxD (65%), and A138T in pmrB (58.6%). The colistin minimum inhibitory concentrations (MICs) of the isolates having any of these four mutations were higher than the isolates with no mutations ( p  < 0.001). The two most common mutations in pmrC (I42V and L150F) were found to be associated with higher expressions of pmrA and pmrC and higher colistin MIC values ( p  = 0.010 and 0.031). All isolates were bla OXA-23 positive. Conclusion: Coexistence of the lpxD mutation along with mutations in pmrCAB indicates synergistic function of these genes in development of colistin resistance in A. baumannii .

Objectives: We describe the molecular characteristics of colistin resistance and its impact on patient mortality., Methods: A prospective cohort study was performed in seven different Turkish hospitals. The genotype of each isolate was determined by MLST and repetitive extragenic palindromic PCR (rep-PCR). Alterations in mgrB were detected by sequencing. Upregulation of pmrCAB, phoQ and pmrK was quantified by RT-PCR. mcr-1 and the genes encoding OXA-48, NDM-1 and KPC were amplified by PCR., Results: A total of 115 patients diagnosed with colistin-resistant K. pneumoniae (ColR-Kp) infection were included. Patients were predominantly males (55%) with a median age of 63 (IQR 46-74) and the 30 day mortality rate was 61%. ST101 was the most common ST and accounted for 68 (59%) of the ColR-Kp. The 30 day mortality rate in patients with these isolates was 72%. In ST101, 94% (64/68) of the isolates had an altered mgrB gene, whereas the alteration occurred in 40% (19/47) of non-ST101 isolates. The OXA-48 and NDM-1 carbapenemases were found in 93 (81%) and 22 (19%) of the total 115 isolates, respectively. In multivariate analysis for the prediction of 30 day mortality, ST101 (OR 3.4, CI 1.46-8.15, P = 0.005) and ICU stay (OR 7.4, CI 2.23-29.61, P = 0.002) were found to be significantly associated covariates., Conclusions: Besides ICU stay, ST101 was found to be a significant independent predictor of patient mortality among those infected with ColR-Kp. A significant association was detected between ST101 and OXA-48. ST101 may become a global threat in the dissemination of colistin resistance and the increased morbidity and mortality of K. pneumoniae infection.

Bloodstream infections caused by Escherichia coli ST131 and ST131 H30-Rx subclones have emerged worldwide. This study was carried out to evaluate the prevalence of the ST131-Rx subclone and characterize the virulence properties of the Rx isolates among the bloodstream E. coli isolates. A total of 297 non-duplicated E. coli bloodstream isolates were studied. Antibiotic susceptibilities were tested using the disc diffusion method. PCR amplification and sequencing was used to identify ST131 and H30-Rx, the virulence gene, the β-lactamase and virotype. Quinolone resistance among bacteraemic E. coli strains was 51 %, and it was 98 % among E. coli ST131 isolates. The ST131 isolates accounted for 16 % (49) of all isolates and all ST131 isolates belonged to the extraintestinal pathogenic E. coli . The proportion of H30 subclone among the ST131 isolates was 98 %, and 75 % of H30 isolates belonged to the H30-Rx subclone. The prevalence of ST131 increased from 13 to 23 % in 4 years; however, there was a decrease in the ratio of H30-Rx infections. CTX-M-15 was detected in 85 % of ST131 and all of the H30-Rx isolates. The virulence genes associated with adhesion, cell protection, iron uptake and toxins ( papA, iha, kpsMTII, iut and sat ) were more common in ST131 than in non-ST131 isolates. Most of the ST131 and H30-Rx isolates were of the C virotype. All papA -positive isolates were in virotype C. The E. coli ST131 clone has increased rapidly among bloodstream isolates. However, a decrease in the proportion of the H30-Rx subclone in the quinolone-resistant population suggests the possibility of dissemination of other virulent and quinolone-resistant subclones in hospital settings.

Although West Nile virus (WNV) serologic evidence has been well demonstrated throghout Turkey in the last 40 years; the first symptomatic WNV infection was reported in 2009 and increased number of cases were reported during August 2010. In that period WNV encephalitis was diagnosed serologically (WNV IgM positivity in serum sample detected by ELISA and IFA) and confirmed by plaque reduction neutralization test in a 76-year-old man who was admitted to Baskent University Faculty of Medicine with complaints of fever, impaired consciousness and generalized tremors. Despite all supportive treatment, he died on the 9th day of hospitalization. In this report, detailed clinical course, laboratory features and diagnosis of this mortal case of WNV encephalitis were described. WNV encephalitis should be considered in the differential diagnosis of patients with fever of unknown origin and loss of consciousness especially in summer and early fall in Turkey.

Mycobacterium fortuitum is a rapidly growing environmental mycobacteria, frequently isolated from water, dust, and soil, which commonly causes infection in the presence of underlying disease or immunosuppression. Skin, soft tissue, and bones are important sites of M. fortuitum, but it may colonize in the respiratory tract as well. We report the case of an otherwise healthy man who presented with signs and symptoms of community-acquired pneumonia. He was diagnosed as having primary infection with M. fortuitum and treated with multidrug antibacterial therapy. Our case confirms that M. fortuitum poses a threat not only to patients with immune defects but also to immunocompetent hosts. Flexible bronchoscopy or a transthoracic needle aspiration may be required to confirm the diagnosis.

The aim of this prospective cohort study was to determine the risk factors for community-acquired urinary tract infections (UTIs) caused by extended-spectrum beta-lactamase (ESBL)-positive Escherichia coli and the distribution of the ESBL enzyme types. Structured forms were filled in for patients diagnosed with community-acquired UTI in four different geographical locations in Turkey. The forms and the isolates were sent to the central laboratory at Baskent University Hospital, Ankara. Antimicrobial susceptibility was determined according to the CLSI criteria. PCR and DNA sequencing were used to characterize the bla(TEM), bla(CTX-M) and bla(SHV) genes. Multivariate analysis was performed using logistic regression. A total of 510 patients with UTI caused by Gram-negative bacteria were included in this study. ESBLs were detected in 17 of 269 (6.3%) uropathogenic E. coli isolates from uncomplicated UTIs and 34 of 195 (17.4%) E. coli isolates from complicated UTIs (p <0.001). According to multivariate analysis, more than three urinary tract infection episodes in the preceding year (OR 3.8, 95% CI 1.8-8.1, p <0.001), use of a beta-lactam antibiotic in the preceding 3 months (OR 4.6, 95% CI 2.0-0.7, p <0.001) and prostatic disease (OR 9.6, 95% CI 2.1-44.8, p 0.004) were found to be associated with ESBL positivity. The percentages of isolates with simultaneous resistance to trimethoprim-sulphamethoxazole, ciprofloxacin and gentamicin were found to be 4.6% in the ESBL-negative group and 39.2% in the ESBL-positive group (p <0.001). Forty-six of 51 ESBL-positive isolates (90.2%) were found to harbour CTX-M-15. Therapeutic alternatives for UTI, particularly in outpatients, are limited. Further clinical studies are needed to guide the clinicians in the management of community-acquired UTIs.

Background: Renal transplant recipients (RTRs) often develop bacterial infections as a result of their long-term immunosuppressive treatment. However, there is no published case-control study of cutaneous bacterial infections in this population, and the prevalence of nasal Staphyloccus aureus carriage and its role in cutaneous bacterial infections in RTRs are not known., Aims: To determine whether the prevalence of cutaneous bacterial infections and nasal S. aureus carriage are increased in RTRs and to investigate the association between nasal S. aureus carriage and cutaneous staphylococcal infections., Methods: In total, 66 outpatient RTRs and 67 controls were investigated for the presence of cutaneous bacterial infections. Bacterial cultures were taken from clinically suspicious cutaneous lesions, and three nasal swabs were collected to detect nasal S. aureus colonization., Results: Cutaneous bacterial infection was suspected in 42.4% of RTRs, and in 14.2% of controls. However, of the lesions that could be cultured, microbiologically proven cutaneous bacterial [methicillin-sensitive S. aureus (MSSA)] infections were confirmed in only two RTRs and one control subject. Nasal S. aureus carriage was found in 10.6% of RTRs and 29.9% of controls (P < 0.05). Both RTRs with MSSA infection were nasal carriers, whereas nasal S. aureus carriage was not detected in the only control subject with MSSA infection. All S. aureus isolates were oxacillin-sensitive., Conclusion: Screening for nasal S. aureus carriage does not seem to assist in preventing staphylococcal bacterial infections in outpatient RTRs.

Infections in burn patients are usually caused by multidrug-resistant micro-organisms. Tigecycline, a derivative of glycylcyclines, is an effective antibiotic against the resistant strains. The aim of this study is to determine the in vitro activity of tigecycline against the multidrug-resistant bacteria isolated from burn patients. Fourty-seven bacteria isolated from 118 patients hospitalized in the burn unit during 2003-2006 were included in the study. Gram-negative bacteria that were resistant to at least six broad-spectrum antibiotics, methicillin-resistant staphylococci and ampicillin-resistant enterococci were studied. Minimal inhibitory concentration values of tigecycline against these bacteria were tested by E-test strips. Susceptibility breakpoints were determined according to the previous studies;

Urinary tract infection (UTI) is the most common infectious complication following renal transplantation. The purposes of this study were to determine the causative agents of UTIs among renal transplant recipients and to compare the antibiotic susceptibilities of Escherichia coli strains isolated from renal transplant recipients and complicated community-acquired UTIs. We evaluated 75 episodes of 63 recipients with confirmed UTI who underwent transplantation during the period 1981 to 2006 at our center. Medical records of the patients were reviewed retrospectively. To compare the susceptibility rates of E coli, 226 isolates from nontransplant patients with complicated community-acquired UTIs were also evaluated. Ten episodes (13.3%) occurred in the first month following the transplantation, 11 (14.7%) in the period of the second month to the sixth month, and 54 (72%) after the sixth month of transplantation. Forty-six (61.3%) isolates were E coli. Among these isolates, ciprofloxacin resistance rates were 50% (2/4) in the first month after transplantation, 75% (6/8) in the period of the second month to the sixth month, and 32.4% (11/34) beyond 6 months after transplantation. The resistance rates of trimethoprim/sulfamethoxazole (TMP-SMX) in the same time periods were 100% (4/4), 87.5% (7/8), and 70.6% (24/34), respectively. The rates of resistance to TMP-SMX among E coli isolated from renal recipients were significantly higher than those in community-acquired complicated UTIs. The increased resistance of urinary pathogens to this agent is a major concern. Although high resistance rates of ciprofloxacin against E coli strains were determined in this group, it was not found to be statistically significant.

Biofilm producing Candida species are known to be more resistant to immune response and antimicrobial agents which leads to treatment failure. The aim of this study was to investigate the biofilm production among Candida species that were isolated from hospitalized patients and to compare the in vitro activities of antifungal agents with biofilm production. A total of 116 Candida spp. (79 C. albicans and 37 non-albicans Candida spp.) isolated from various specimens (blood, sterile body fluids, mucosal and skin lesion samples) were included to the study. Fluconazole, itraconazole, amphotericin B and caspofungin susceptibilities of the isolates were determined by broth microdilution method according to CLSI M27-A2 standards. Biofilm production of Candida spp. was determined by microplate method, using brain heart infusion broth supplemented with 0.25% glucose as a growth medium. Biofilm formation was detected in 33 of 116 isolates (28%) and 11 of them (33%) were the strains isolated from hemocultures. Biofilm production was determined more commonly in blood isolates than the strains isolated from other samples (p < 0.05). The biofilm production rate of non-albicans Candida species (41%) was found higher than C. albicans (23%), which the difference was statistically significant (p < 0.05). Amphotericin B and caspofungin were found the most effective antifungals with the MIC90 values of 0.06 microg/ml and 0.5 microg/ml for C. albicans, and 0.5 microg/ml and 1 microg/ml for non-albicans Candida species respectively. The observed positive correlation between the biofilm production and amphotericin B MIC values were found significant (p < 0.05). In conclusion, high biofilm production rates of Candida species may explain the increase in the rate of catheter-related Candida infections.