Comparative analysis of linezolid, vancomycin, and hyperbaric oxygen therapies in a rat model of ventriculoperitoneal shunt infection.

PURPOSE: Staphylococcus epidermidis is the most common causative microorganism of ventriculoperitoneal shunt infections. This study aimed to compare linezolid and vancomycin treatments and to examine the effect of these antibiotics alone and combined with hyperbaric oxygen therapy on the amount of bacterial colonies in the experimental S. epidermidis shunt infection model. METHODS: A shunt catheter was placed in the cisterna magna of 49 adult male Wistar albino rats. The rats were randomly divided into seven groups, as follows: sterile control, infected control, vancomycin, linezolid, hyperbaric oxygen, vancomycin + hyperbaric oxygen, linezolid + hyperbaric oxygen. In all groups except the sterile control group, 0.2 ml 107 CFU/mL S. epidermidis was inoculated to the cisterna magna. Parenteral vancomycin was administered 40 mg/kg/day to the vancomycin groups, and 50 mg/kg/day of enteral linezolid to the linezolid groups. Hyperbaric oxygen groups were given 100% oxygen at a pressure of 2.4 ATA for 50 min a day. One day after the last treatment, colony quantities in the shunt catheters and CSF were analyzed. RESULTS: The number of CSF colonies in the linezolid group was significantly lower than in the vancomycin group (p < 0.05). The number of CSF colonies in the linezolid + HBO group was significantly lower than in the vancomycin + HBO group (p < 0.05). CONCLUSIONS: Linezolid treatment was found to be more effective than vancomycin in ventriculoperitoneal shunt infection caused by S. epidermidis. There was no statistical difference among other treatment groups. Hyperbaric oxygen therapy is shown to contribute to the sterilization of cultures.

Identification of Molecular and Genetic Resistance Mechanisms in a Candida auris Isolate in a Tertiary Care Center in Türkiye.

BACKGROUND: Candida auris is a multidrug-resistant pathogen that causes nosocomial outbreaks and high mortality. We conducted this study to investigate the molecular mechanisms of antifungal resistance in our clinical isolate of C. auris with a high level of resistance to three main classes of antifungals. MATERIAL AND METHODS: A clinical C. auris isolate was identified by MALDI-TOF MS and antifungal susceptibilities were determined by the Sensititre YeastOne YO10 panel. After sequencing the whole genome of the microorganism with Oxford Nanopore NGS Technologies, a phylogenetic tree was drawn as a cladogram to detect where the C. auris clade to this study's assembly belongs. RESULTS: The C. auris isolate in this study (MaCa01) was determined to be a part of the clade I (South Asian). The resistance-related genes indicated that MaCa01 would most likely be highly resistant to fluconazole (CDR1, TAC1b, and ERG11), none or little resistant to amphotericin B (AmpB) and echinocandins, and sensitive to flucytosine. The mutations found in the above-mentioned genes in the Türkiye C. auris isolate reveals an antifungal resistance pattern. This molecular resistance pattern was found consistent with the interpretation of MIC values of the antifungals according to CDC tentative breakpoints. CONCLUSION: We detected the well-known antifungal resistance mutations, responsible for azole resistance in C. auris. Despite no ERG2, ERG6, and FKS mutation identified, the isolate was found to be resistant to AmpB and caspofungin based on the CDC tentative breakpoints which could be related to unidentified mutations.

Nosocomial infection of C. auris in COVID-19 Intensive Care Unit in Türkiye and Phylogenetic Analysis of Isolates.

BACKGROUND: The difficulties in the identification of C. auris and the delays in the implementation of infection control precautions contribute to outbreaks. This study analyzed 10 patients with COVID-19 and C. auris candidemia, their characteristic and clinical features and phylogenetic features, and the antifungal susceptibilities of the isolates. METHOD: C. auris were detected in the COVID-19 ICU of a university hospital between January and August 2021. Identification to species level was performed using MALDI-TOF MS. Antifungal susceptibilities were determined by the Sensititre YeastOne YO10 panel. The isolates were whole genome sequenced to assess genetic relatedness and a phylogenetic tree was drawn including various C. auris clades. RESULTS: The mean growth time in blood cultures was 38.8 h. C. auris candidemia developed on the average 27th day of ICU admission. All were susceptible to anidulafungin and micafungin, while they were resistant to fluconazole and amphotericin B. Only three isolates were found to be resistant to caspofungin. All patients died. With the WGS method, all isolates were found in a close resemblance to each other in terms of total nucleotide similarity (with a minimum of 96% pairwise alignment). Our isolates showed the closest similarity to South Asian clade (Clade I). CONCLUSIONS: This study is the first to evaluate the phylogenetic characteristics of C. auris using WGS and to determine antifungal susceptibilities in Türkiye on COVID-19 patients. The mortality rate was very high in patients who have both COVID-19 and C. auris candidemia.

An outbreak investigation of Burkholderia cepacia infections related with contaminated chlorhexidine mouthwash solution in a tertiary care center in Turkey.

BACKGROUND: We report a nosocomial outbreak caused by Burkholderia cepacia that occurred among six patients admitted in the medical and surgical intensive care unit between 04 March 2019 and 02 April 2019 in Istanbul, Turkey. METHODS: The outbreak investigation was launched on 11 March 2019 five days after the detection of B. cepacia in four different patients. We defined potential reservoirs and started environmental screening. We sampled the liquid solutions used in patient care activities. Pulse-field gel electrophoresis (PFGE) was performed to determine the genetic relatedness of environmental and patient samples. RESULTS: Burkholderia cepacia was isolated in tracheal aspiration cultures of six patients. Three out of six patients developed healthcare-associated pneumoniae due to B. cepacia. Environmental cultures in the ICUs revealed B. cepacia growth in 2% chlorhexidine-gluconate mouthwash solution that been used in the colonized patients as well as in samples obtained from the unused products. PFGE revealed the patient and a specific batch of chlorhexidine mouthwash solution samples had a 96% similarity. CONCLUSION: Contamination of medical solutions used in critical patient care could cause outbreaks and should be detected early by infection control teams.

Sepsis caused by Anaerococcus nagyae after transarterial-chemoembolization for hepatocellular carcinoma: Case report and literature review.

Hepatocellular carcinoma (HCC) is more common in patients with chronic viral hepatitis infection and cirrhosis. Transarterial chemoembolization (TACE) is an effective treatment method for unresectable HCC. A rare complication of TACE is the development of bloodstream infection. We present a fatal case of sepsis due to Anaerococcus nagyae after TACE.

Frequency and associated factors for carbapenem-non-susceptible Bacteroides fragilis group bacteria colonization in hospitalized patients: Case control study in a university hospital in Turkey.

PURPUSE: The carbapenem-resistant Bacteroides fragilis group (CR-BFG) bacteria have been reported in several countries recently with increasing global attention. The high incidence of CR-BFG isolated from our hospitalized patients has become an important problem. Therefore, we aimed to determine the frequency and associated factors for intestinal colonization by carbapenem-non-susceptible BFG (CNS-BFG) among adult patients hospitalized at intensive care units, neurosurgery and internal medicine wards in our hospital. METHODS: Rectal swabs (n = 1200), collected from 766 patients between February 2014 and March 2015, were inoculated onto kanamycin-vancomycin-leaked blood agar containing 0.125 mg/L meropenem. The isolates were identified by MALDI-TOF MS. Susceptibility testing was performed by agar dilution method. The carbapenemase gene (cfiA) was detected by PCR. Logistic regression analysis was used to evaluate the associated factors for intestinal colonization by CNS-BFG. RESULTS: A total 180 non-duplicate BFG isolates were obtained from 164 patients. Ten different species, including Parabacteroides distasonis (n = 46, 25.6%), and Bacteroides fragilis (n = 30; 16.6%), were identified. Twenty-five percent of the isolates were non-susceptible to meropenem (MIC >2 mg/L). The highest prevalence of meropenem resistant strains (MIC >8 mg/L) was detected among B. fragilis (n = 12), followed by Parabacteroides spp. (n = 4). All but one B. fragilis strains were cfiA gene positive. Hospital admission, increasing Charlson score, use of antibiotics; including carbapenems in past three months, colonization with other accompanying carbapenem-resistant Gram negative bacteria (Enterobacteriaceae, Acinetobacter baumannii and Pseudomonas aeruginosa), and having undergone surgical operations were significantly associated with RCS- BFG colonization. CONCLUSIONS: The high carriage rate of CNS-BFG in hospitalized patients may lead to worse clinical outcomes, such as serious infections and mortality, and deserves attention.

Relationship of the cycle threshold values of SARS-CoV-2 polymerase chain reaction and total severity score of computerized tomography in patients with COVID 19.

AIM: Studies analyzing viral load in COVID-19 patients and any data that compare viral load with chest computerized tomography (CT) severity are limited. This study aimed to evaluate the severity of chest CT in reverse transcriptase polymerase chain reaction (RT-PCR)-positive patients and factors associated with it. METHODOLOGY: SARS-CoV-2 RNA was extracted from nasopharyngeal swab samples by using Bio-speedy viral nucleic acid buffer. The RT-PCR tests were performed with primers and probes targeting the RdRp gene (Bioexen LTD, Turkey) and results were quantified as cycle threshold (Ct) values. Chest CT of SARS-CoV-2 RNA-positive patients (n = 730) in a period from 22 March to 20 May 2020 were evaluated. The total severity score (TSS) of chest CT ranged 0-20 and was calculated by summing up the degree of acute lung inflammation lesion involvement of each of the five lung lobes. RESULTS: Of the 284 patients who were hospitalized, 27 (9.5%) of them died. Of 236 (32.3%) patients, there were no findings on CT and 216 (91.5%) of them were outpatients (median age 35 years). TSS was significantly higher in hospitalized patients; 5.3% had severe changes. Ct values were lower among outpatients, indicating higher viral load. An inverse relation between viral load and TSS was detected in both groups. CT severity was related to age, and older patients had higher TSS (p < 0.01). CONCLUSION: Viral load was not a critical factor for hospitalization and mortality. Outpatients had considerable amounts of virus in their nasopharynx, which made them contagious to their contacts. Viral load is important in detecting early stages of COVID-19, to minimize potential spread, whereas chest CT can help identify cases requiring extensive medical care.

[In Vitro Activities of Antimicrobials Against Toxigenic Clostridioides difficile Isolates Obtained in a University Training and Research Hospital in Turkey]. / Türkiye'deki Bir Üniversite Egitim ve Arastirma Hastanesinde Elde Edilen Toksijenik Clostridioides difficile Izolatlarina Antimikrobiyallerin In Vitro Etkisi.

Clostridioides difficile, a gram-positive, anaerobic, spore forming bacillus known as Clostridium difficile according to the previous taxonomy, is the most important agent of antibiotic-associated diarrhea. C.difficile infections have become a major health problem for many countries. The rate of antimicrobial resistant C.difficile isolates is rapidly increasing all around the world. Yet there is limited data on this subject in our country. The aim of this study was to determine the antimicrobial susceptibility profiles of C.difficile strains isolated from stool samples in Marmara University Pendik Training and Research Hospital Microbiology Laboratory. A total of 93 toxigenic C.difficile, defined by serological and molecular techniques, were included in this study. Antimicrobial susceptibility profiles of isolates were determined by using agar dilution method according to the Clinical and Laboratory Standards Institute (CLSI; M11-A7). The following antimicrobials commonly used for the treatment of C.difficile infections or applied previously in C.difficile epidemiological studies were tested: metronidazole, vancomycin, meropenem, ceftriaxone, ampicillin-sulbactam, clindamycin, erythromycin, moxifloxacin, tetracycline, doxycycline, tigecycline and linezolid. The minimum inhibitory concentration (MIC) results were interpreted according to the breakpoints described by the European Committee on Antimicrobial Susceptibility Testing (EUCAST). Breakpoints recommended by CLSI were applied for ceftriaxone, clindamycin, tetracycline and moxifloxacin since there were no EUCAST breakpoints for these antimicrobials. MIC50 and MIC90 values were determined for three antimicrobials (linezolid, erythromycin, doxycycline) whose breakpoints were not described by EUCAST or CLSI guidelines. All isolates were susceptible to metronidazole, vancomycin, ampicillin-sulbactam, meropenem and tetracycline. Susceptibility to ceftriaxone, clindamycin and moxifloxacin was found in 58.1%, 35.5% and 20.4% of the isolates, respectively. MIC50 and MIC90 values of tigecycline, erythromycin linezolid, doxycycline were 0.125-0.25 mg/L, 1-2 mg/L, 2-2 mg/L, 0.062- 0.125 mg/L, respectively. This study shows the current antimicrobial susceptibility patterns of C.difficile isolates in our hospital and will also be the reference data for clinical laboratories in our country where anaerobic culture and susceptibility tests are not performed in routine practice. In conclusion, two main antimicrobial agents commonly used in the treatment of C.difficile infections, metronidazole and vancomycin, seem to be effective. However, high resistance rates against to the certain tested antimicrobials highlight the need for further surveillance to monitor the emergence of resistance.

Hospital acquired Clostridioides difficile infection and risk factors for severity in a university hospital: A prospective study.

BACKGROUND: Clostridioides difficile infection (CDI) is a well-known cause of health care-associated diarrhea. Data about CDI epidemiology of Turkey is limited. This study investigates CDI incidence, clinical characteristics, and factors associated with severe CDI in a tertiary care center university hospital. METHODS: This is a case control study was conducted between 2012 and 2016. We included all patients, 18 years of age or more, with CDI diagnosis. For each patient diagnosed with CDI, information was collected concerning the severity of disease, treatment regimen, treatment response, disease recurrence, 30-day case fatality. Cases defined as severe hospital acquired CDI (HA-CDI) and controls defined as non-severe CDI patients. RESULTS: We identified 100 cases of HA-CDI out of 111 patients. Total CDI incidence was 1.19/10,000 patient-days. The incidence decreased 32.5% during the study period. We identified severe CDI in 24% of patients. Age and admission to intensive care unit were independent risk factors for severe CDI. CONCLUSION: This study reports a 5-year prospective epidemiology of CDI in a tertiary care center in Istanbul, Turkey. The findings of this study suggest that HA-CDI incidence and proportion of severe CDI is low compared to European and US literature. We believe that CDI is underreported, neglected but still an important health care associated infection in Turkey.

Vibrational spectra, powder X-ray diffractions and physical properties of cyanide complexes with 1-ethylimidazole.

The heteronuclear tetracyanonickelate(II) complexes of the type [M(etim)Ni(CN)4]n (hereafter, abbreviated as M-Ni-etim, M=Mn(II), Fe(II) or Co(II); etim=1-ethylimidazole, C5H8N2) were prepared in powder form and characterized by FT-IR and Raman spectroscopy, powder X-ray diffraction (PXRD), thermal (TG; DTG and DTA), and elemental analysis techniques. The structures of these complexes were elucidated using vibrational spectra and powder X-ray diffraction patterns with the peak assignment to provide a better understanding of the structures. It is shown that the spectra are consistent with a proposed crystal structure for these compounds derived from powder X-ray diffraction measurements. Vibrational spectra of the complexes were presented and discussed with respect to the internal modes of both the etim and the cyanide ligands. The C, H and N analyses were carried out for all the complexes. Thermal behaviors of these complexes were followed using TG, DTG and DTA curves in the temperature range 30-700 °C in the static air atmosphere. The FT-IR, Raman spectra, thermal and powder X-ray analyses revealed no significant differences between the single crystal and powder forms. Additionally, electrical and magnetic properties of the complexes were investigated. The FT-IR and Raman spectroscopy, PXRD, thermal and elemental analyses results propose that these complexes are similar in structure to the Hofmann-type complexes.

CH⋯Pd interactions: one dimensional heteropolynuclear complexes.

Three cyanide complexes, [Cu(hepH)2Pd(µ-CN)2(CN)2]n (1), [Zn(hepH)2Pd(µ-CN)2(CN)2]n (2) and [Cd(hepH)2Pd(µ-CN)2(CN)2]n (3) (2-pyridineethanol abbreviated to hepH), have been synthesized and characterized by various techniques (elemental analysis, FT-IR and Raman spectroscopy, thermal analysis and single crystal X-ray diffraction). FT-IR spectroscopy pointed out the existence of terminal and bridged cyanide ligands in the complexes. The crystallographic analyses reveal that complexes 1 and 2 crystallize in the triclinic system, space group P-1 and complex 3 crystallizes in the monoclinic system, space group P21/n. The palladium atom is coordinated with cyanide-carbon atoms in a square-planar arrangement and the metal(II) atoms are six-coordinated with two cyanide nitrogen, two hepH nitrogen and two hepH oxygen atoms, in a distorted octahedral arrangement. In all the complexes adjacent chains are connected by CH⋯Pd, π⋯π and OH⋯N hydrogen bonding interactions to form two- and three-dimensional networks. When it comes to thermal analysis, the complexes followed usual decomposition mechanism in which neutral ligands (hepH) are released first, and then cyanide ligands are decomposed. The final decomposition products are found to be the corresponding metal oxides.

[The first metronidazole-resistant Bacteroides species isolated at Marmara University Hospital: Bacteroides thetaiotaomicron]. / Marmara Üniversitesi Hastanesi'nde Izole Edilen Ilk Metronidazole Dirençli Bacteroides Kökeni: Bacteroides thetaiotaomicron.

Bacteroides species, the predominant constituents of the human intestinal microbiota can cause serious intraabdominal and postoperative wound infections and bacteremia. Moreover, these bacteria are more resistant to antimicrobial agents than the other anaerobes. The limited number of the antimicrobials, such as carbapenems, beta-lactam/beta-lactamase inhibitors and nitroimidazoles are highly effective in eliminating Bacteroides. However, a few metronidazole-resistant isolates have been reported from several countries recently. The nim genes (nim A-G) are suggested to be responsible for the majority of the metronidazole resistance. Here, we describe a metronidazole-resistant Bacteroides thetaiotaomicron isolated from a blood culture. A gram-negative obligate anaerobic rod was isolated from the postoperative 5th day blood culture of a 62-year-old male patient with adenocarcinoma of the pancreas head. The strain was identified as B.thetaiotaomicron by using a combination of conventional tests and commercially available biochemical kits. Antimicrobial susceptibility testing was performed by agar dilution method. The resistance genes were investigated by means of PCR using specific primer pairs for nim gene. The purified PCR product was sequenced and analyzed by comparison of the consensus sequences with GenBank sequences. The MIC for metronidazole was 16 mg/L. Although the strain was intermediate according the CLSI criteria, it was resistant (> 4 mg/L) according to EUCAST criteria. The isolate was nim gene positive, and nucleotide sequencing of the PCR product shared 100% similarity with nimE gene (emb |AM042593.1 |). On the other hand the isolate was susceptible to carbapenems and sulbactam-ampicillin. Following administration of ampicillin-sulbactam, the patient's fever disappeared after 24 hours. The clinical condition improved considerably and he was discharged at day 8. The patient was followed up at the medical oncology clinic; however he died due to disease progression six months after surgery. Since anaerobic bacteremia is associated with high mortality rate, prompt diagnosis and proper management are critical. The studies on Bacteroides bacteremia have revealed adverse outcomes in patients receiving antibiotics to which the bacterium was resistant. In the present case, the metronidazole-resistant organism would be reported as susceptible according to CLSI breakpoint value and on account of this result the treatment might lead to clinical failure. Therefore EUCAST MIC values seem to be more rational in case of Bacteroides antibiotic susceptibility testing.