Improved ß-Lactam Susceptibility Against ica-Dependent Biofilm-Embedded Staphylococcus aureus by 2-Aminothiazole.

BACKGROUND: Due to the emergence of methicillin-resistant Staphylococcus aureus (MRSA) producing biofilm, causing recurrent infections worldwide, new therapeutic combinations need to be discovered to prevent resistance and to make treatment available. It was aimed to improve ß-lactam susceptibility against ica-dependent biofilm-embedded Staphylococcus aureus (S. aureus), even in blaZ and mecA carriers, by 2-aminothiazole. METHODS: Virulence genes in isolates were detected by qRT-PCR. MICs, MBCs of 2-aminothiazole and ß-lactams against planktonic and sessile ica-dependent biofilm-producer isolates were investigated. Activities of 2-aminothiazole combined ß-lactams against sessile one MRSA ATCC 43300, one MRSA, and two MSSA were investigated by checkerboard-assay. RESULTS: Activities of 2-aminothiazole combined ß-lactams were found synergistic and partially-synergistic against both biofilm-embedded MRSA and MSSA-isolates with FIC-indexes ranging between 0.193 - 0.387 and 0.535 - 0.745 and between 0.358 - 0.415 and 0.707 - 1.0, respectively. MICs of ß-lactams against MSSA and MRSA were decreased 2- to 8-fold and 0- to 8-fold by sub-MICs of 2-aminothiazole, respectively. CONCLUSIONS: Sub-MIC 2-aminothiazole combined Sub-MIC ß-lactams can be a choice in varying applications to treat biofilm-associated staphylococcal infections.

The Prevalence of Periodontal Pathogenic Bacteria in Atherosclerotic Cardiovascular Disease.

BACKGROUND: A possible link between periodontal pathogenic bacteria and atherosclerosis may exist based on the inflammatory mechanisms initiated by bacteria found in periodontal lesions. Our aim was to investigate the presence of DNA originating from T. denticola, C. rectus, T. forsythia, and P. gingivalis in the vascular tissue specimens obtained from patients who underwent surgery for arteriosclerotic vascular disease in this study. METHODS: A total of 96 patients diagnosed with valvular heart disease due to atherosclerosis and 85 patients with advanced aortic valve stenosis due to rheumatic fever and had undergone aortic valve replacement were included as the study (PG) and the control groups (CG), respectively. Atheroma plaques and vascular tissue specimens were collected from PG and CG during cardiovascular surgical procedures. Revitalization of the lyophilized T. denticola, ATCC 35405; C. rectus, ATCC 33238; P. gingivalis, ATCC 33277 and T. forsythia, ATCC 43037 strains was performed according to the manufacturer's instructions. C. rectus, T. forsythia, and T. denticola DNA samples were analyzed using the one-step in-house PCR method. RESULTS: In one (1.04%) and three (3.13%) out of 96 atherosclerotic PG tissue specimens, P. gingivalis and T. for-sythia DNA were detected, respectively. No T. denticola or C. rectus DNA was found in the study specimens. Periodontal pathogenic bacteria were not observed in 85 CG tissue specimens. There was no statistically significant difference between PG and CG for the presence of P. gingivalis and T. forsythia DNA using Fischer's Exact test (p > 0.05). CONCLUSIONS: In conclusion, with the case-control studies on a small scale such as in our study, it is not possible to determine a causality relationship between periodontal pathogenic bacteria and formation of atherosclerosis. Periodontal pathogenic bacteria may not be the only factor that causes inflammatory diseases associated with atherosclerosis. Host response and inflammatory mechanisms may be affected by other factors such as ethnicity, dietary habits, nutritional availability, and lifestyle. Taken together, it is difficult to conclude a causal link between periodontal pathogenic bacteria and formation of atherosclerosis.

Sensitizing of ß-lactam resistance by tannic acid in methicillin-resistant S. aureus.

Methicillin-resistant Staphylococcus aureus (MRSA) infections treatment of which is hard and failed, due to being resistant to all types of ß-lactams, have been emerged in hospitals and community. Long-term usage of antibiotics and over doses of antibiotics used in the treatment of infections cause bacteria to develop resistance to antibiotics. ß-lactams combined with tannic acid can be a good alternative to sensitize the resistance of ß-lactams used in the treatment of MRSA, due to their synergistic activities. In this study, after minimal inhibitory concentrations (MICs) and minimal bactericidal concentrations (MBCs) of sole tannic acid and ß-lactam were investigated for each isolate, the synergistic activities of ß-lactams combined with tannic acid against one MRSA ATCC 43300 and four MRSA clinical isolates were investigated with the concentrations starting at four fold of MICs of sole treatments of tannic acid and ß-lactam by using checkerboard assay. To investigate sole and combination activities of tannic acid and ß-lactams, MIC and MBCs were observed. Results of this study showed that the activities of ß-lactams combined with tannic acid were synergistic and partially synergistic against MRSA isolates with FIC indexes ranged from 0.174 to 0.477 and 0.562 to 0.850, respectively. MIC of ß-lactams were decreased 2-16 fold by sub-inhibitory concentrations of tannic acid without toxicity. Alternative treatment options of natural compounds such as tannic acid and ß-lactams must be investigated further and developed to overcome the emergence of ß-lactam resistance and treat MRSA infections by sensitizing the resistance of ß-lactams.

Identification of ica-dependent biofilm production by Staphylococcus aureus clinical isolates and antibiofilm effects of ascorbic acid against biofilm production.

AIMS: Staphylococcus aureus (S. aureus) is a life-threatening pathogen with high morbidity and mortality rates which causes nosocomial and community-acquired infections. Biofilm, considered to be a common virulence factor for pathogens, plays a significant role in recurrent and untreatable infections. Biofilm formation of S. aureus is mediated by synthesis of either poly-N-acetylglucosamine in an ica-dependent manner or surface proteins in an ica-independent manner. In some cases treatment is impossible and recurrent. In this study, ica-dependent biofilm-producing S. aureus isolates were detected and the anti-biofilm effect of ascorbic acid against biofilm formation of isolates was investigated. METHODS: A total of 21 methicillin-sensitive S. aureus (MSSA) clinical isolates stored in our bacterial stock were used to detect ica-dependent biofilm-producing MSSA isolates. The anti-biofilm study was undertaken with three ica-dependent biofilm-producing isolates (MSSA2-4) and ATCC 29213 (MSSA1). Biofilms and the anti-biofilm effect of ascorbic acid were detected using the microtitre plate (MtP) method. 16S-rRNA, nuc, icaA and icaD genes and expression levels of icaA and icaD of isolates were detected by RT-PCR. RESULTS: The minimum inhibitory concentrations (MICs) of ascorbic acid prevented biofilm formation of MSSA1 and MSSA3. Also, 1/2 MIC of ascorbic acid prevented biofilm formation of MSSA3. It was observed that biofilm formation decreased with increased concentration. There was no significant increase in ica gene expression of MSSA1 and MSSA2. Expression of icaA and icaD of MSSA3 decreased 13% and 38%, respectively. Expression of icaA in MSSA4 decreased 12%. CONCLUSION: The results of our study show that ascorbic acid can be used as an anti-biofilm agent to prevent biofilm formation of S. aureus and thus biofilm-related infections.

Association between human leukocyte antigen gene polymorphisms and multiple EPIYA-C repeats in gastrointestinal disorders.

BACKGROUND: Polymorphisms of human leukocyte antigen (HLA) genes are suggested to increase the risk of gastric cancer (GC). AIM: To investigate the HLA allele frequencies of patients with GC relative to a control group in terms of CagA+ multiple (≥ 2) EPIYA-C repeats. METHODS: The patient group comprised 94 patients [44 GC and 50 duodenal ulcer (DU) patients], and the control group comprised 86 individuals [(50 non-ulcer dyspepsia patients and 36 people with asymptomatic Helicobacter pylori (H. pylori)]. Polymerase chain reaction was performed for the amplification of the H. pylori cagA gene and typing of EPIYA motifs. HLA sequence-specific oligonucleotide (SSO) typing was performed using Lifecodes SSO typing kits (HLA-A, HLA-B HLA-C, HLA-DRB1, and HLA-DQA1-B1 kits). RESULTS: The comparison of GC cases in terms of CagA+ multiple (≥ 2) EPIYA-C repeats showed that only the HLA-DQB1*06 allele [odds ratio (OR): 0.37, P = 0.036] was significantly lower, but significance was lost after correction (Pc = 0.1845). The HLA-DQA1*01 allele had a high ratio in GC cases with multiple EPIYA-C repeats, but this was not significant in the univariate analysis. We compared allele frequencies in the DU cases alone and in GC and DU cases together using the same criterion, and none of the HLA alleles were significantly associated with GC or DU. Also, none of the alleles were detected as independent risk factors after the multivariate analysis. On the other hand, in a multivariate logistic regression with no discriminative criterion, HLA-DQA1*01 (OR = 1.848), HLA-DQB1*06 (OR = 1.821) and HLA-A*02 (OR = 1.579) alleles were detected as independent risk factors for GC and DU. CONCLUSION: None of the HLA alleles were detected as independent risk factors in terms of CagA+ multiple EPIYA-C repeats. However, HLA-DQA1*01, HLA-DQB1*0601, and HLA-A*2 were independent risk factors with no criterion in the multivariate analysis. We suggest that the association of these alleles with gastric malignancies is not specifically related to cagA and multiple EPIYA C repeats.

Evaluating the effectiveness of anti-tuberculosis treatment by detecting Mycobacterium tuberculosis 85B messenger RNA expression in sputum.

BACKGROUND: The antigen 85 complex (85B) is secreted in large quantities from growing mycobacteria and the presence of bacterial mRNA is an indicator of cell viability. The quantitative detection of 85B mRNA expression levels can be used to assess the success of anti-tuberculosis treatment outcomes to detect viable mycobacteria cells. Therefore, we evaluated the levels of 85B mRNA of Mycobacterium tuberculosis strains in patients with pulmonary tuberculosis. METHODS: Thirty patients with primary tuberculosis were included in this study. The sputum specimens of patients were collected on days 0, 15, and 30 days and were cultured and evaluated by 85B mRNA-based RT-qPCR. RESULTS: Overall, 23 of the studied tuberculosis strains were susceptible to the primary anti-tuberculosis antibiotics used in this study, 7 were resistant. By the 30th day of treatment, 85B mRNA was detected in only one of the susceptible strains, but in all 7 of the resistant strains, though the relative gene expression varied between the strains. This difference between the susceptible and resistant strains at day 30 was statistically significant (p < 0.05). CONCLUSION: 85B mRNA expression levels could be used to follow up on primary tuberculosis cases. 85B mRNA seems to be a good diagnostic marker for monitoring anti-tuberculosis treatment outcomes.

The Effect of Urinary Catheters on Microbial Biofilms and Catheter Associated Urinary Tract Infections.

PURPOSE: The aims of this study were to determine relationship between biofilm producer microorganisms attached to urinary catheters (UCs) and urinary catheter-associated urinary tract infections (CAUTIs), to determine the rate of CAUTI development and the relationship between CAUTI and catheterization period in catheterized patients. MATERIALS AND METHODS: Urinary catheters from 143 inpatients who were hospitalized in Abant Izzet Baysal University Hospital Urinary Service, and urine samples of these patients before and after catheterization of urinarycatheter were collected. Culture-based microbiological evaluation of urinary catheters removed from inpatient and urine samples collected from inpatients were performed before and after catheterization of urinary catheter to identify various organisms and determine biofilm production by them. RESULTS: The incidence of CAUTIs was 13% (18/143) in catheterized inpatients. Biofilm producer microorganisms such as Escherichia coli (E. coli ), Klebsiella pneumoniae, Pseudomonas aeruginosa, Proteus mirabilis that were isolated from UCs removed from inpatients were found to cause CAUTI (P < .001). CONCLUSION: Incidence of CAUTIs is increased by the usage of UCs and prolonged catheterization period.