Determination of the Cytotoxicity and Antibiofilm Potential Effect of Equisetum arvense Silver Nanoparticles.

This study aimed to synthesize and characterize silver nanoparticles (AgNPs) by green synthesis from Equisetum arvense (Ea) extracts and to investigate their cytotoxicity, antibiofilm activity, and α-glucosidase enzyme inhibition. Diverse characterization techniques were applied to verify the production of nanoparticles. SEM examination confirmed that the size of nanoparticles is in the range of 40-60 nm. Also, interactions between silver and natural compounds of plant extract were confirmed through FT-IR and EDX analyses. It was determined that Equisetum arvense silver nanoparticles had antibiofilm activity against three different clinical strains with high biofilm-forming ability. AgNPs reduced the biofilm-forming capacity of clinical A. baumannii isolate with strong biofilm-forming capacity by approximately twofold, while the capacity of clinical K.pneumonaie and E.coli isolates decreased by 1.5 and 1.2 fold, respectively. The α-glucosidase enzyme inhibition potential of the AgNPs, which is determined as 93.50%, was higher than the plant extract with, and the α- 30.37%. MTT was performed to assess whether incubation of nanoparticles with A549 and ARPE-19 cell lines affected their viability, and a dramatic reduction in cell growth inhibition of both A549 and ARPE-19 cells was observed. It has been shown that A549 cells treated with 200 and 150 µg/mL nanoparticles had less cell proliferation compared to control cells at 24-h and 48-h incubation time. According to these results, Ea-derived AgNPs appear to have potential anticancer activity against A549 cancer cells. Investigating the effects of green synthesis nanoparticles on microbial biofilm and various tumors may be important for developing new therapies. The outcomes of this study have showed that Ea-AgNPsmay have a high potential both in the treatment of pathogenic strains that form biofilms, as well as in anticancer therapy use.

Stenotrophomonas maltophilia outbreak originating from a pull-out faucet in a pediatric intensive care unit in Turkey: Insights from clinical records and molecular typing.

BACKGROUND: Nosocomial Stenotrophomonas maltophilia-related cases are rising and pose a threat to immunocompromised patients. Twelve patients from our pediatric intensive care unit (PICU) presented with S maltophilia-associated bloodstream infection. METHODS: This outbreak investigation includes 12 patients from PICU between the ages of 2 months and 4 years (mean 16 months, 7 male). To identify the origin, samples from all possible sources throughout the hospital were collected and ran through DNA isolation and Pulse Field Gel Electrophoresis. RESULTS: 120 samples were collected during the outbreak. 31 samples (26%) were positive for S maltophilia. 30 S maltophilia isolates were analyzed, 10 different genotypes were identified. Clustering isolates were grouped into 3 different clusters (tolerance and optimization 1.0, cutoff 90%). The largest cluster was genotype 1, which included 19 isolates, those belong to patients' samples and a sample from a pull-out faucet inside the PICU. The Pull-out faucet was the origin of the bloodstream infection. DISCUSSION: Pull-out faucets allow biofilm production, due its structure. Pulse Field Gel Electrophoresis identifies the transmission dynamics of the outbreak, with its high discriminatory power. CONCLUSIONS: Water sources should be monitored on a regular basis. Pull-out faucets enable bacterial overgrowth; therefore, we recommend water surveillance during outbreak investigations.

Evaluating molecular epidemiology of carbapenem non-susceptible Klebsiella pneumoniae isolates with MLST, MALDI-TOF MS, PFGE.

BACKGROUND: This study aimed to evaluate antibiotic resistance genes and virulence genes and the clonal relationship of the carbapenem-nonsusceptible Klebsiella pneumoniae strains by molecular methods which are isolated from various clinical specimens from patients treated in tertiary care hospital in Turkey. METHODS: Identification of 32 carbapenem non-susceptible K. pneumoniae were determined by VITEK-2 (BioMérieux, France) automated system. Thirteen colistin-resistant strains were tested with the broth microdilution method. Various antibiotic resistance genes and virulence genes frequently seen in carbapenem-resistant strains were screened by PCR. Immunochromatographic tests used in the rapid diagnosis of carbapenemases were compared with PCR results. In addition, PFGE, MLST and MALDI-TOF MS methods were used to determine the clonal relationship among these strains. RESULTS: PCR demonstrated that 31 of the strains carried at least one of the carbapenemase genes. In one strain, the coexistence of blaOXA-48+NDM was shown. The most common resistance genes were determined as blaSHV (84.3%), blaCTX-M-1 (46.8%), blaOXA-48 (40.6%), blaKPC (40.6%), blaTEM (31.2%), blaNDM (18.8%) respectively. Among the virulence genes; magA (68.7%) was the most common, followed by kpn (59.3%) and K2 (9.3%). Immunochromatographic tests were found to be 100% compatible with PCR results. All colistin-resistant isolates were also found to be resistant by colistin broth microdilution. In PFGE analysis, 25 different genotypes were determined and clustering isolates were collected in 5 different clusters and the clustering rate was 35.4%. In MLST analysis, ST101 type was determined as the most common ST type with a rate of 29%. ST101 is followed by ST16, ST307, ST14, ST147, ST309, ST377, ST395 and ST2096, respectively. The compatibility rate between MALDI-TOF MS and VITEK-2 was found 94.3%, in bacterial identification. In MALDI-TOF MS typing, the maximum similarity between the strains was less than 70% and clustering not shown. CONCLUSION: In addition to OXA-48, which is endemic in our country, it has been determined that KPC, which is more common in the world, is becoming increasingly common in our region. ST101 type was determined as the most common type between the strains. To the best of our knowledge, this is the first study that compares these three methods in our country. There may be differences between bacterial identifications made with VITEK-2 and MALDI-TOF MS. In this study, it was observed that MALDI-TOF MS analyses were not compatible with the typing of strains according to PFGE and MLST analysis results.

Molecular epidemiological analysis of integron gene cassettes and tetA/tetB/tetD gene associations in Escherichia coli strains producing extended-spectrum ß-lactamase (ESBL) in urine cultures.

BACKGROUND: Epidemiological studies of tetracycline (TE) resistance genes and integron gene cassettes, particularly in urine samples, are limited in Turkey. OBJECTIVES: To investigate antibiotic susceptibility profiles, extended-spectrum beta-lactamase (ESBL) positivity, tet gene types, class-I/-II integron gene cassettes, and clonal relationships among tet-resistant isolates of Escherichia coli from urine cultures of outpatients. MATERIAL AND METHODS: Isolates were identified using conventional methods and the automated Vitek® 2 Compact system. Antimicrobial susceptibility was performed for 19 antibiotics. The ESBL production was performed using the Kirby-Bauer disk diffusion test. The double disk synergy test was used for confirmatory testing. Polymerase chain reaction (PCR) was used to determine the presence of class-I/-II integron gene cassettes and tetA, tetB and tetD resistance genes. The pulsed-field gel electrophoresis typing was performed to identify clonal relations. RESULTS: A total of 121 isolates were obtained and found to be resistant or sensitive to ampicillin and amikacin/imipenem. Resistance to ceftazidime, cefotaxime and ceftriaxone was determined to be 31.3%, 77.6% and 83.1%, respectively. Tetracycline resistance was detected in 82 isolates, mostly caused by the tetB gene. No tet gene was detected in the remaining 39 isolates. Although 64 out of 82 isolates carried a class-I integron, only 4 had a class-II integron (with sizes of 800-2900 base pairs). Furthermore, tet genes were identified with different size class-I integron gene cassettes. However, tet genes were not detected in any isolate identified with integron gene cassette II. Clonally, the isolates were found to be related in subgroups because they were community-acquired. CONCLUSIONS: This study showed that the tetB gene is most commonly found in E. coli isolates grown in urine samples from the Turkish population.

Screening of Antimicrobial Resistance Genes and Epidemiological Features in Hospital and Community-Associated Carbapenem-Resistant Pseudomonas aeruginosa Infections.

INTRODUCTION: Researching carbapenem-resistant isolates enables the identification of carbapenemase-producing bacteria and prevents their spread. METHODS: P. aeruginosa isolates were recovered from Medicine Faculty of Recep Tayyip Erdogan University and identified by conventional methods and the automated Vitek 2 Compact system. Antimicrobial susceptibility experiments were performed in accordance with CLSI criteria and the automated Vitek 2 Compact system. The PCR method was investigated for the presence of ß-lactamase resistance genes. PFGE typing was performed to show clonal relation among samples. RESULTS: Seventy P. aeruginosa isolates were isolated from seventy patients. Of the patients, 67.1% had contact with the health service in the last 90 days and 75.7% of the patients had received antimicrobial therapy in the previous 90 days. Twenty-four isolates were carbapenem resistant, 2 isolates were multidrug-resistant except colistin, and none of the samples had colistin resistance. The gene encoding ß-lactamase or metallo-ß-lactamase was found in a total of 36 isolates. The bla VEB and bla PER genes were identified in 1 and 5 isolates alone or 17 and 13 isolates in combination with other resistance genes, respectively. The bla NDM was the most detected metallo-ß-lactamase encoding gene (n=18), followed by bla KPC (n=12). bla IMP and bla VIM were detected in 5 and 1 isolates, respectively. Also, the association of bla VEB-bla PER and bla VEB-bla KPC-bla NDM was found to be very high. Much more resistance genes and co-occurrence were detected in hospital-acquired samples than community-acquired samples. No difference was found between the community and hospital-associated isolates according to PFGE results. Simultaneously from 6 patients, other microorganisms were also isolated and 5 of them died. CONCLUSION: The average length of stay (days) was found to be significantly higher in HAI group than CAI group. The death of 5 patients with fewer or no resistance genes showed that the co-existence of other microorganisms in addition to resistance genes was important on death.

The Antibiotic sensitivity of Stenotrophomonas maltophilia in a 5-year period and investigation of clonal outbreak with PFGE.

INTRODUCTION: Stenotrophomonas maltophilia, which is able to form a biofilm, has mostly been related to catheters when it is the agent in hospital infections; these infections generally present as bacteremia and pneumonia, which may progress with complications and result in death. METHODOLOGY: The study included 153 S. maltophilia strains isolated from clinical samples sent to our hospital laboratory between 1 January 2014 and 30 June 2018. The bacteria were identified and their antibiotic sensitivity was determined using the VITEK-2 automated system. PFGE (Pulsed Field Gel Electrophoresis): The strains isolated from 34 patient clinical samples and from 1 patient bedcover were taken for PFGE examination. RESULTS: The TMP/SXT and levofloxacin sensitivity of 153 S. maltophilia strains was examined. TMP/SXT resistance was determined to be 39% and levofloxacin resistance at 5%. Among 35 S. maltophilia strains, seven genotypes were identified using the PFGE method. While three strains showed a specific genotype profile, the other 32 were determined to consist of four clusters. The cluster rate was therefore 91.4% (32/35). CONCLUSIONS: There was a clonal relationship between the vast majority of the 35 S. maltophilia isolates, which suggests that there was a cross-contamination problem in the hospital. One strain (#4) was identified by dendrogram analysis showed a high rate of similarity to the other strains and was determined to be the common source of the cross-contamination.

PaCaHa inhibits proliferation of human cancer cells in vitro.

BACKGROUND/AIM: The aim of this study was to investigate the antiproliferative and cytotoxic effects of a newly synthesized molecule named paracetamol acetohydroxamic acid (PaCaHa) on human neoplastic cell lines. MATERIALS AND METHODS: A549, CRL 2923, HeLa, and ARPE were treated with various concentrations of PaCaHa and DMSO (vehicle control). The cytotoxic/cytostatic effects of PaCaHa were determined after a 24-h incubation period and compared to the DMSO control. The cytotoxic and antiproliferative effects were determined by the trypan blue dye exclusion and MTT methods. RESULTS: A higher susceptibility to PaCaHA was found in CRL 2923 and HeLa cells, while A549 and ARPE cells were less responsive to PaCaHa. The percent of cytotoxicity resulting from 400 µg/mL of PaCaHa were >90 for CRL-2923 and HeLa, 68 for A549, and 64 for ARPE cells. The cytotoxic difference between CRL-2923/HeLa and ARPE/A549 cells was significant (P < 0.05). CONCLUSION: PaCaHa showed dose dependent cytotoxic and antiproliferative effects on three distinct human cancer cell lines. The differential effect of PaCaHa on different cancer cell lines suggests that PaCaHa could have a potential antitumor effect on specific cancer types. These results support further comprehensive studies on PaCaHa and its derivatives.

[Antimicrobial susceptibility and molecular characterization of multidrug-resistant Acinetobacter baumannii isolated in an university hospital]. / Bir üniversite hastanesinde izole edilen çok ilaca dirençli Acinetobacter baumannii izolatlarinin antimikrobiyal duyarliligi ve moleküler karakterizasyonu.

Acinetobacter baumannii, an aerobic, non-motile, gram-negative bacterium is an important nosocomial pathogen which shows resistance to the most antibiotics. Carbapenems are the most commonly used antibiotics for the treatment of infections caused by this pathogen. However the emergence of resistance against carbapenems in an increasing rate generates serious problems for antimicrobial therapy. The aims of this study were to detect the antibiotic susceptibility, and the presence of blaOXA resistance genes of clinical A.baumannii isolates and to determine the clonal relationship between these isolates. A total of 79 A.baumannii strains isolated from various clinical specimens (37 respiratory tract samples, 11 wound, 10 blood, 8 catheters, 6 tissue, 5 urine, 2 abscess) of the patients admitted to Mersin University Medical School Hospital between May 2012-January 2013, were included in the study. The isolates were identified by conventional methods and Vitek®2 Compact automated system. Antibiotic susceptibilities of the isolates were determined by Kirby-Bauer disk diffusion method and evaluated according to CLSI criteria. The presence of blaOXA-51, blaOXA-23, blaOXA-24, blaOXA-48 and blaOXA-58 genes were detected by an in-house polymerase chain reaction (PCR), and the clonal relationship between the isolates were identified by pulsed-field gel electroforesis (PFGE) using the ApaI restriction enzyme. In our study, all of the isolates were susceptible to colistin, while the resistance rates against piperacillin-tazobactam, ciprofloxacin, imipenem, meropenem, cefoperazone/sulbactam, trimethoprim-sulfamethoxazole, ceftazidime, levofloxacin, gentamicin, tetracycline, ampicillin-sulbactam, amikacin, netilmicin and tigecycline were 97.5%, 96.2%, 94.9%, 94.9%, 93.6%, 91.1%, 88.6%, 86%, 83.6%, 77.2%, 69.6%, 55.7%, 27.8% and 3.8%, respectively. All the isolates were identified as A.baumannii with the OXA-specific PCR and OXA16S rDNA sequence analysis. All of the isolates (100%) harboured blaOXA-51 and 71 (89.9%) harboured blaOXA-23 gene, however they were all negative for blaOXA-24, blaOXA-48 and blaOXA-58 genes. According to PFGE results 10 pulsotypes were identified, of these eight pulsotypes formed 77 (97.5%) similar strains with indistinguishable PFGE profiles ranging between 3-30 [A (n= 30), B (n= 20), C (n= 9), D (n= 5), E (n= 4), F (n= 3), G (n= 3), H (n= 3)]. When compared with the other clones, clones A and B were dominant among the samples and they have exhibited high level of antibiotic resistance. The rest two pulsotypes [I (n= 1), J (n= 1)] were in close relation with the main cluster. No common outbreak isolate was detected, but the relationship between the majority of the strains pointed out that there was a cross contamination problem in our hospital. In conclusion blaOXA-51 and blaOXA-23 were detected as predominant genes responsible from carbapenem resistance in our clinical A.baumannii strains, and it was considered that the high prevalence of clones A and B may constitute a threat in terms of hospitalized patients.