Different Combinations Of Antibiotics Research Articles

DESIGN AND OPTIMIZATION OF OCULAR INSERTS FOR PROLONGED DELIVERY OF CIPROFLOXACIN WITH CORTICOSTEROID

Ocular drug delivery is very challenging and fascinating for pharmaceutical researchers, especially in the treatment of ocular conjunctivitis. The challenges include delivery of the drug to the eye without causing permanent tissue damage while maintaining a stable therapeutic level at the site of action for a prolonged period of time. The present work focuses on the treatment of ocular conjunctivitis by using combined mechanisms of fluroquinolone antibiotics, providing sustained release of drug from ocular inserts, and using corticosteroid for anti-inflammatory effect and providing comfort to the patient. Quinolone antibiotics, anti-inflammatory agents and polymers with excipients were procured from pharmaceutical companies as gift samples. Different combinations of antibiotics and anti-inflammatory agents were prepared by solvent cast method and the dried films were cut into defined size containing drug and evaluated for different parameters and sustained drug release. Based on in vitro, in vivo correlation stability studies, the formulation (antibiotic + anti-inflammatory agent) promising the best once a day sustained release of the drug has been chosen.

Combination of gentamicin and clindamycin as a promising therapy for multidrug-resistant (MDR) methicillin-resistant Staphylococcus aureus isolated in Enugu State

Objectives: Methicillin-resistant Staphylococcus aureus (MRSA) is prevalent in Nigeria. Due to its increasing resistance to treatments with single antibiotics, such as vancomycin and others, it has become necessary to identify appropriate combination of antibiotics for treatment. This research tested the proneness of MRSA isolated in southeastern Nigeria to a combined treatment of selected antibiotics (vancomycin, clindamycin, gentamicin, and ceftriaxone), to identify the best combination for the treatment of MRSA isolated in the region. Methods: Various samples from patients were obtained in three laboratories in Enugu, Nigeria and cultured for isolation and purification. Minimum inhibitory concentration of vancomycin, clindamycin, gentamicin, and ceftriaxone antibiotics against the purified isolates was determined and the combined activity of the drugs on the isolates was also evaluated using Checkerboard-technique. Results: MRSA isolates were found to be highly prevalent in the clinical samples. They also showed multidrug-resistant traits. The different combinations of antibiotics against different species of MRSA indicated synergistic, indifferent, additive, and antagonistic effects. The best combination that could treat muti-drug resistant MRSA was found to be gentamycin and clindamycin. MRSA has developed resistance to many drugs, making its infections difficult to treat. The combination of gentamicin and clindamycin is a promising strategy for treating MRSA in the region.

An Archetypical Model for Engrafting Bacteroides fragilis into Conventional Mice Following Reproducible Antibiotic Conditioning of the Gut Microbiota.

Bacteroides fragilis is a commonly investigated commensal bacterium for its protective role in host diseases. Here, we aimed to develop a reproducible antibiotic-based model for conditioning the gut microbiota and engrafting B. fragilis into a conventional murine host. Initially, we selected different combinations of antibiotics, including metronidazole, imipenem, and clindamycin, and investigated their efficacy in depleting the mouse Bacteroides population. We performed 16S rRNA sequencing of DNA isolated from fecal samples at different time points. The α-diversity was similar in mice treated with metronidazole (MET) and differed only at weeks 1 (p = 0.001) and 3 (p = 0.009) during metronidazole/imipenem (MI) treatment. Bacteroides compositions, during the MET and MI exposures, were similar to the pre-antibiotic exposure states. Clindamycin supplementation added to MET or MI regimens eliminated the Bacteroides population. We next repeated metronidazole/clindamycin (MC) treatment in two additional independent experiments, followed by a B. fragilis transplant. MC consistently and reproducibly eliminated the Bacteroides population. The depleted Bacteroides did not recover in a convalescence period of six weeks post-MC treatment. Finally, B. fragilis was enriched for ten days following engraftment into Bacteroides-depleted mice. Our model has potential use in gut microbiota studies that selectively investigate Bacteroides' role in diseases of interest.

Evolution of genome fragility enables microbial division of labor.

Division of labor can evolve when social groups benefit from the functional specialization of its members. Recently, a novel means of coordinating the division of labor was found in the antibiotic-producing bacterium Streptomyces coelicolor, where specialized cells are generated through large-scale genomic re-organization. We investigate how the evolution of a genome architecture enables such mutation-driven division of labor, using a multiscale computational model of bacterial evolution. In this model, bacterial behavior-antibiotic production or replication-is determined by the structure and composition of their genome, which encodes antibiotics, growth-promoting genes, and fragile genomic loci that can induce chromosomal deletions. We find that a genomic organization evolves, which partitions growth-promoting genes and antibiotic-coding genes into distinct parts of the genome, separated by fragile genomic loci. Mutations caused by these fragile sites mostly delete growth-promoting genes, generating sterile, and antibiotic-producing mutants from weakly-producing progenitors, in agreement with experimental observations. This division of labor enhances the competition between colonies by promoting antibiotic diversity. These results show that genomic organization can co-evolve with genomic instabilities to enable reproductive division of labor.

The Efficiency of Selected Extenders against Bacterial Contamination of Boar Semen in a Swine Breeding Facility in Western Slovakia.

Simple SummaryThis study evaluated the efficiency of selected semen extenders to prevent bacterial overgrowth in boar ejaculates stored for 72 h. Among the identified bacterial isolates, Escherichia coli and Pseudomonas aeruginosa were the most prevailing species. While all extenders supplemented with antibiotics ensured a satisfactory sperm vitality during the storage period, neither of them was able to achieve a complete elimination of bacteria from extended semen. Furthermore, a number of bacterial isolates exhibited resistance to several antibiotics chosen for the microbial susceptibility test (e.g., tigecyklin and ciprofloxacin).Bacteriospermia has become a serious factor affecting sperm quality in swine breeding, this is why antibiotics (ATBs) are a critical component of semen extenders. Due to ever-increasing antimicrobial resistance, the aim of this study was to assess the efficiency of selected commercially available semen extenders to prevent a possible bacterial contamination of boar ejaculates. Three Androstar Plus extenders containing different combinations of antibiotics were used to process ejaculates from 30 healthy Duroc breeding boars. Androstar Plus without antibiotics was used as a control. The extended samples were stored at 17 °C for 72 h. Sperm motility, viability, mitochondrial activity, DNA integrity and oxidative profile of each extended sample were assessed following 24 h, 48 h and 72 h. Furthermore, selective media were used to quantify the bacterial load and specific bacterial species were identified with matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. The results indicate that semen extenders enriched with ATBs ensured a significantly higher preservation of the sperm quality in comparison to the ATB-free control. The total bacterial count was significantly decreased in the extenders supplemented with ATBs (p < 0.001), however gentamycin alone was not effective enough against Gram-positive bacteria, while a few colonies of Enterococcus hirae, Bacillus subtilis and Corynebacterium spp. were present in the samples extended in the presence of a triple combination of ATBs. In conclusion, we may suggest that semen extenders enriched in antibiotics were not able to fully eliminate the bacteria present in the studied samples. Furthermore, selection of suitable antibiotics for semen extension should be accompanied by adequate hygiene standards during the collection and handling of boar ejaculates.

Combinations of antibiotics and vonoprazan for the treatment of Helicobacter pylori infections-Exploratory study.

BackgroundVonoprazan fumarate is a novel potassium‐competitive acid blocker more effective in suppressing acid production than proton pump inhibitors (PPIs) and when combined with antibiotics has been used to eradicate Helicobacter pylori (H. pylori) infection. However, it has not yet been examined in an Australian setting. This study aimed to report on the efficacy and safety of vonoprazan‐containing antibiotic combination therapies in the eradication of H. pylori.MethodsA single‐center, exploratory, clinical review of patients 18 years or over, positive for H. pylori on Urea Breath Test (UBT), and/or histopathology who underwent a 10‐day treatment of combination antibiotics plus vonoprazan between January 2017 and September 2019 was conducted. Eleven different combinations of antibiotics that included 2–5 different antibiotics predominantly amoxicillin, rifabutin, levofloxacin, furazolidone, nitazoxanide, and tetracycline were included. The eradication success was based on negative UBT results and/or histopathology results after the treatment. Descriptive statistics were summarized.ResultsOne hundred and fifty‐three patients (Female n = 74, 48%) with a positive for H. pylori were treated with vonoprazan‐containing antibiotic combination therapy during the study period. Of the 153 patients, 48 (31%) had previously failed a PPI‐based H. pylori treatment. Follow‐up was available for 66/153 (43%) patients. In those who completed follow‐up, overall eradication was achieved in 97% (64/66) of patients. In the subgroup of patients treated for the first time, eradication was achieved in 100% (44/44). In those who had failed prior, non‐vonoprazan‐containing treatment, eradication was achieved in 91% (20/22) of patients.ConclusionsVonoprazan‐containing antibiotic therapy is an effective H. pylori eradication treatment. It is capable of achieving 100% efficacy in patients treated for the first time and even 91% efficacy in patients with previous eradication failure. Subsequent studies utilizing a factorial design will be needed to optimize each regimen as most regimens contained more than two antibiotics.

The microbial diversity following antibiotic treatment of Clostridioides difficile infection

BackgroundClostridioides difficile (C. difficile) is a major nosocomial pathogen that infects the human gut and can cause diarrheal disease. A dominant risk factor is antibiotic treatment that disrupts the normal gut microbiota. The aim of the study was to examine the correlation between antibiotic treatment received prior to C. difficile infection (CDI) onset and patient gut microbiota.MethodsStool samples were collected from patients with CDI, presenting at the Baruch Padeh Medical Center Poriya, Israel. Demographic and clinical information, including previous antibiotic treatments, was collected from patient charts, and CDI severity score was calculated. Bacteria were isolated from stool samples, and gut microbiome was analyzed by sequencing the 16S rRNA gene using the Illumina MiSeq platform and QIIME2.ResultsIn total, 84 patients with CDI were enrolled in the study; all had received antibiotics prior to disease onset. Due to comorbidities, 46 patients (55%) had received more than one class of antibiotics. The most common class of antibiotics used was cephalosporins (n = 44 cases). The intestinal microbiota of the patients was not uniform and was mainly dominated by Proteobacteria. Differences in intestinal microbiome were influenced by the different combinations of antibiotics that the patients had received (p = 0.022)ConclusionsThe number of different antibiotics administered has a major impact on the CDI patients gut microbiome, mainly on bacterial richness.

Effect of combined colistin and meropenem against meropenem resistant Acinetobacter baumannii and Pseudomonas aeruginosa by checkerboard method: A cross sectional analytical study.

BACKGROUND:Meropenem-resistant Acinetobacter baumannii and Pseudomonas aeruginosa are the two most common nosocomial pathogens causing ventilator-associated pneumonia. To combat this resistance, different combinations of antibiotics have been evaluated for their efficacy in laboratories as well as in clinical situations.AIM:The aim of the study was to investigate the effect of combined colistin and meropenem against meropenem-resistant isolates of A. baumannii and P. aeruginosa by checkerboard method.MATERIALS AND METHODS:Fifty meropenem-resistant isolates of A. baumannii (n = 25) and P. aeruginosa (n = 25) from endotracheal aspirates were studied. The MIC of colistin and meropenem was found using the microbroth dilution method. The fractional inhibitory concentration was calculated for the combination of antibiotics by checkerboard assay and the antibiotic interactions were assessed. Fisher's exact test was carried out for statistical comparison of categorical variables.RESULTS:A synergistic effect between colistin and meropenem was observed in 18/25 (72%) and 6/25 (24%) isolates of Acinetobacter baumannnii and P. Aeruginosa, respectively, with fractional inhibitory concentration indices of ≤0.5. None of the tested isolates exhibited antagonism.CONCLUSION:Our results showed that combinations of colistin and meropenem are associated with improvement in minimum inhibitory concentration and may be a promising strategy in treating meropenem-resistant A. baumannii respiratory tract infections.

Identification and Prevention of Microbial Contamination in Tissue Culture of Catharanthus roseus - An Important Medicinal Herb

The explants of two varities rosea and alba of Catharanthus roseus used for in vitro propagation and found to be more than 50% of the cultures became contaminated. The most common bacterial contaminants were Bacillus licheniformis, Micrococcus, Panibacillus and fungal contaminants were Fusarium, Alternaria, Cladosporium and Aspergillus. Combinations of different antibiotics (Penicillin, norfloxacin, tobramycin, gatifloxacin, ofloxacin) and fungicides (Bavastin, captan, fluconazole and trichoderma) were used to control the growth of the contaminants. Gatifloxacin and ofloxacin inhibited 100% growth of bacteria whereas, bavastin and captan appeared to be the most effective fungicides. Combination of gatifloxacin, ofloxacin with bavastin and captan inhibited the growth of contaminants at their minimum phytotoxic concentration (MIC). The observed minimum phytotoxic concentration (MPC) of ofloxacin, gatifloxacin, bavastin and captan was 15, 9, 6 and 5% at their respective MIC. More than 90% of the cultures responded for callus formation in the combination of gatifloxacin (4%) + bavastin (1%). While the combination of gatifloxacin and captan was highly toxic that reduces the growth of the culture.&#x0D; Plant Tissue Cult. &amp; Biotech. 30(2): 297-305, 2020 (December)

Adventitious Shoot Regeneration from In Vitro Leaf Explants of the Peach Rootstock Hansen 536.

In the present study, an efficient system for the in vitro regeneration of adventitious shoots from the peach rootstock Hansen 536 leaves has been established. Twenty regeneration media containing McCown Woody Plant Medium (WPM) as a basal salt supplemented with different concentrations and combinations of plant growth regulators (PGRs) were tested. Expanded leaves along with their petiole from 3-week-old elongated in vitro shoot cultures were used as starting explants. The highest regeneration rate (up to 53%) was obtained on WPM basal medium enriched with 15.5 μM N6-benzylaminopurine (BAP). The influences on leaf regeneration of the ethylene inhibitor silver thiosulphate (STS) and of different combinations of antibiotics added to the optimized regeneration medium were also investigated. The use of 10 μM STS or carbenicillin (238 μM) combined with cefotaxime (210 μM) significantly increased the average number of regenerating shoots per leaf compared to the control. In vitro shoots were finally elongated, rooted and successfully acclimatized in the greenhouse. The results achieved in this study advances the knowledge on factors affecting leaf organogenesis in Prunus spp., and the regeneration protocol described looks promising for the optimization of new genetic transformation procedures in Hansen 536 and other peach rootstocks and cultivars.

Virulence, antimicrobial resistance and phylogenetic analysis of zoonotic walking pneumonia Mycoplasma arginini in the one-humped camel (Camelus dromedarius)

In the scientific literature, a small amount of information is found concerning mycoplasmosis in camel species. A variety of pathogens could be causative agents for pneumonia, but walking pneumonia is mostly caused by Mycoplasma with slow development and mild symptoms. The aim of this study was to identify mycoplasmas from camels (Camelus dromedarius) and extending the arsenal of factors implicated in pathogenicity of M. arginini to shed light on the current knowledge gap. 460 lung samples (pneumonic; n=210 and apparently healthy; n=250) were randomly collected from the one-humped camels (C. domedarius) that have been imported from Sudan and slaughtered at Cairo Slaughterhouse. 48 out of 210 isolates (22.9%) recovered from the pneumonic lungs were recorded as M. arginini. Positive PCR results were obtained for all 48 isolates. On the other hand, infection with the organism was not detected in the apparently healthy lungs. Hemolysis and hydrogen sulphide (H2S) production, a compound that has previously not been identified as a virulence factor in M. arginini, was evident in 100% of the isolates. The 48 M. arginini isolates were weak in their ability to form biofilm on polystyrene surfaces. All isolates were 100% susceptible to florfenicol and streptomycin and 100% resistant to ciprofloxacin. Resistance to lincomycin, spiromycin, tylosin, doxacyclin and erythromycin was observed at different frequencies. 13 different combinations of antibiotics representing one to four classes were evident with the Macrolide erythromycin being the most represented. It also should be noted that the ciprofloxacin, doxacyclin, lincomycin, erythromycin combination was the most noted in 21/48 isolates. Surprisingly, none of the virulence genes (vsp, uvrC and gapA) and quinolone resistance genes (parC and gyrA) were detected by PCR.

Effect of different combinations of antibiotics on fruit quality and antioxidant defense system in Huanglongbing infected Kinnow orchards

Huanglongbing (HLB), also known as citrus greening disease, is the most devastating disease of citrus across the world, caused by the phloem limited fastidious bacterium ‘Candidatus Liberibacter spp.’. This research was conducted on HLB infected 10-year-old Kinnow orchard located at Multan, Pakistan. Different classes of antibiotics in various combinations were applied on HLB-infected trees. The antibiotic treatments were applied before flowering in February, during fruit setting in April and at fruit growth stage in June. The different antibiotics combinations used were Ampicillin sodium + Rifampicin, Cefalexin + Rifampicin, Ampicillin sodium + Cefalexin, Ampicillin sodium + Cefalexin + Rifampicin and Control (distilled water). Different fruit qualitative and quantitative attributes were examined. The application of antibiotics significantly decreased 2–11% in flower, June and pre-harvest drops as compared to control. Further, antibiotics increased fruit weight and yield by five times while the juice content, total soluble solids, ripening index, total sugars, phenolic and vitamin C content were also increased in fruits. In addition, total soluble proteins, peroxidase and catalase activities were increased in fruits harvested from antibiotic treated plants compared to control, however the superoxidase dismutase activity was decreased in fruits of antibiotic treated plants. Finally, it is concluded that application of different antibiotics combinations helps in improving the fruit yield and different quality attributes of HLB infected Kinnow trees.

Management of bacterial canker of tomato caused by Clavibecter michiganensis subsp. michiganensis (Smith and Davis et al.) using different antibiotics

In an attempt to control bacterial canker of tomato, a very hard-to-control disease, both in-vitro and in-vivo studies were conducted using antibiotics alone or in combinations with other antibiotics and with copper oxychloride. Using paper disc diffusion assay and 50 ppm - 400 ppm concentrations, tetracycline+streptomycin produced the largest inhibition zone (22.8 mm) followed by tetracycline alone (22.0) at highest concentration after 48 hrs incubation. The result of antibiotic combination streptomycin and gentamicin were statistically at par with those of tetracycline+streptomycin combination. However, streptomycin alone proved to be ineffective. Antibiotic concentrations of 250 ppm and higher were sufficient to inhibit the in-vitro bacterial growth. In case of screen-house studies, combination of tetracycline and copper oxychloride gave minimum % disease severity (5.40%), as compared to inoculated but untreated control in which case the % disease severity was 56.6 %. The same combination (i.e. tetracycline+copper oxychloride) also proved to be more effective than other treatments in term of enhancing yield per plant (1147.7g), plant height (102.0 cm), plant dry weight (130.8g) and other parameters. The better performance of this combination treatment could be attributed to its interactive effect. This study suggested that combination of antibiotics should be used for proper disease management and further combinations of different antibiotics in different concentrations should be evaluated. Keywords: Antibiotics; Bacteria; Clavibecter; Tomato http://dx.doi.org/10.19045/bspab.2019.80128

Risk factors and clinical responses of pneumonia patients with colistin-resistant Acinetobacter baumannii-calcoaceticus.

BACKGROUNDNosocomial infections with carbapenem-resistant Acinetobacter baumannii-calcoaceticus complex (ABC) strains are great problem for intensive care units. ABC strains can develop resistance to all the antibiotics available. Carbapenem resistance is common and colistin resistance is rare in our country. Knowing the risk factors for colistin resistance is important since colistin seems to be the only remaining therapeutic option for the patients with pneumonia due to extensively drug resistant ABC for our country.AIMTo investigate the comparison of clinical responses and outcomes between pneumonia patients with colistin-susceptible and -resistant Acinetobacter sp. Strains.METHODSDuring the study period, 108 patients with pneumonia due to colistin-susceptible strains and 16 patients with colistin-resistant strains were included retrospectively. Continuous variables were compared with the Mann-Whitney U test, and categorical variables were compared using Pearson’s chi-square test or Fisher’s Exact chi-square test for two groups. A binary logistic regression model was developed to identify the potential independent factors associated with colistin resistance in patients with colistin-resistant strains.RESULTSHigh Acute Physiology and Chronic Health Evaluation II scores (OR = 1.9, 95%CI: 1.4-2.7; P < 0.001) and prior receipt of teicoplanin (OR = 8.1, 95%CI: 1.0-63.3; P = 0.045) were found to be independent risk factors for infection with colistin-resistant Acinetobacter sp. Different combinations of antibiotics including colistin, meropenem, ampicillin/sulbactam, amikacin and trimethoprim/sulfamethoxazole were used for the treatment of patients with colistin-resistant strains. Although the median duration of microbiological cure (P < 0.001) was longer in the colistin-resistant group, clinical (P = 0.703), laboratory (P = 0.277), radiological (P = 0.551), microbiological response (P = 1.000) and infection related mortality rates (P = 0.603) did not differ between the two groups. Among the patients with infections due to colistin-resistant strains, seven were treated with antibiotic combinations that included sulbactam. Clinical (6/7) and microbiological (5/7) response rates were quite high in these patients.CONCLUSIONThe optimal therapy regimen is unclear for colistin-resistant Acinetobacter sp. infections. Although combinations with sulbactam seems to be more effective in our study patients, data supporting the usefulness of combinations with sulbactam is very limited.

Evaluation of Antimicrobial Efficacy of Three Combinations of Different Antibiotics against Microorganisms in Gingival Abscess – An in Situ Study

Background: It is important to maintain primary dentition in the dental arch to facilitate the development of permanent teeth, in spite of teeth with infected root canals. Antimicrobial agents have been used, but, even a broad spectrum antibiotic could not eradicate all the bacteria from the periapical lesions. An in situ study was carried out with the aim to evaluate the antimicrobial efficacy of combinations antibiotics against microorganisms in a gingival abscess or primary tooth root canals.&#x0D; Methodology: Thirty children with gingival abscess secondary to pulp infection or infected primary tooth root canals were randomly selected for the study. Swabs of gingival abscess microbial content were used for development of bacteria in suitable media containing three combinations of antibiotics, under aerobic and anaerobic incubation. Ciprofloxacin, Minocycline were used with metronidazole, ornidazole, tinidazole antibiotics to form three different combinations. The antimicrobial efficacy was measured in terms of the diameter of the zone of inhibition around the antibiotic discs.&#x0D; Results: The three combinations of antibiotics exhibit equivalent efficacy for aerobic as well as anaerobic bacteria, and the difference in efficacy between them was not statistically significant (p &gt; 0.05). There was no difference in pair-wise significance between the groups.&#x0D; Conclusion: In view of the equivalent antibacterial activity of the three classes, towards the two types of bacteria, a group containing ornidazole was found to be superior with more favorable side effect profile compared to metronidazole.

International Practices for Driveline Exit Site Care and Infection Prevention in Ventricular Assist Devices

Purpose Despite the high prevalence of driveline (DL) exit site infections, there is a lack of evidence-based practice guidelines for overall DL exit site care and infection prevention. This study aimed to explore current international practices for DL exit site care and preventing infection. Methods Members (n=248) of the International Consortium of Circulatory Assist Clinicians were asked to complete a self-administered online survey. The survey consisted of 37 items using multiple choice and “select all that apply” answers, delineating infection prevention practices and DL exit site care in the inpatient (pre, intra, and post-operative) and outpatient care settings. Respondents were given 30 days to complete the survey. Data were analyzed with descriptive and inferential statistics. Results There were 15 ways to evaluate infection and 25 different combinations of antibiotics administered pre-implant. Initial DL dressing changes reported by most centers (76%) were performed within 48 hours post-implant. Half of respondents reported daily dressing changes on hospitalized patients. Although 34% had no knowledge about their infection data, 66% reported that their two-year DL infection rates ranged from 0 to 20%. We found no significant associations among frequency of dressing changes, use of antibiotics, staff providing education, and infection rates. However, transplant/VAD centers were more likely to have staff dedicated for performing dressing changes for patients (X2 [3, n=23]=14.21, p=0.003). Conclusion This preliminary study showed multiple strategies in infection prevention and care of DL exit sites in the setting of high infection rates. Future studies are needed to address the limitations inherent to the present research design. A large multinational VAD center study is needed to validate our data and explain the mechanism of the effects of preventive and treatment strategies of DL infections. Solid evidence is needed to inform standard of care for DL exit site care and infection control.

Various antibiotic combinations against carbapenem resistant Acinetobacter baumannii infections and in vitro synergy test results (2002-2016)

Carbapenem resistant Acinetobacter baumannii is a bacterium that causes various hospital acquired infections, primarily ventilator-associated pneumonia and bloodstream infections. The multidrug resistance problem of the bacteria all over the world, is also a problem in our center. As the treatment options are decreasing combination therapies become a current issue. It is believed that in vitro synergy tests may guide to the selection of antibiotic combinations. The aim of this study was to present the antibiotic combinations used in the treatment of carbapenem resistant A.baumannii infections and the synergy test results of these combinations. A total of 71 carbapenem-resistant A.baumannii isolates from various clinical samples of patients in Hacettepe University Adult and Oncology Hospitals was included in the study. All isolates were from nosocomial infections that were being requested for synergy testing by the consulting physicians in the Department of Infectious Diseases and Clinical Microbiology between January 2002 and December 2016. Only one isolate from one patient was included in the analysis. The synergy test for these isolates was performed by E-test method. Of the total, 41 (58%) isolates were from various clinical samples of patients in intensive care units and 30 (42%) were from patients in different wards. Twenty-three of the isolates were obtained from bronchoalveolar lavage (BAL) fluid, 18 from pus, 14 from deep tracheal aspirate, 6 from central venous catheter, 5 from blood and 5 from other various samples. The fractional inhibition concentration (FIC) index for each combination was calculated and the results were interpreted as synergistic, additive, indifferent and antagonist. A total of 38 different combinations of antibiotics were tested. According to the frequency of synergistic activity, the combinations were; meropenem-colistin (11/12), meropenem-amikacin (7/9), meropenem-tobramycin (9/13), rifampicin-colistin (7/11), cefaperazone-sulbactam-tobramycin (8/16) and sefaperazon-sulbactam-amikacin (5/10). The most common antagonistic combinations were tigecyclin-colistin (2/6), meropenem-tobramycin (3/13), cefepim-tobramycin (4/19), rifampicin-colistin (2/11) combinations. In our center, different combinations of antibiotics are being used for the treatment of carbapenem-resistant A.baumannii due to the changing and increasing antibiotic resistance of the bacteria over the years. Sensitivity tests as well as synergy tests are used when selecting different combinations of antibiotics. However generalizability of the synergistic effect of combinations is limited. It is important to repeat these studies at regular intervals. In addition there is also a need for further studies to evaluate the correlation between in vitro laboratory results and in vivo clinical compliance.

The evaluation of the transport medium for extracted premolars prior to cryopreservation: a systematic literature review.

Prior to cryopreservation, a tooth is transported from a contaminated oral environment to the tooth bank. Our objective was to identify all studies reporting or investigating a transport protocol prior to the cryopreservation of teeth, in terms of decontamination of the subjects. The systematic literature search (1970-2017) was based on MEDLINE via PubMed, Web of Science and the Cochrane Library. The reference lists of the included studies and the Science Citation Index were used for hand searching (snowballing). Only studies reporting the transport conditions of the transplant were included. Language restrictions for English, Dutch or French were applied. The search led to 14 eligible studies. Almost all studies were laboratory studies, so the methodological quality of evidence was low. The majority of the included studies was performed by only five different research groups and the number of subjects varied between 1 and 120 teeth. In general, the teeth were stored in a tissue culture medium supplemented with fetal calf serum and/or different combinations of antibiotics and/or antimycotics. The teeth were transported cooled (4°C) or at room temperature, for a period of time not exceeding 24h. Only three studies reported the irrigation of the teeth with phosphate buffered saline prior to the transport. The optimisation of the decontamination during transport was investigated in three studies (from 1971, 1980 and 1982). It was concluded that the literature on this topic is scarce, and the decontamination protocol for teeth, prior to cryopreservation has not been validated recently.

Screening and Potential of Multi-drug Resistance in Gram-Negative Bacteria from Hospital Wastewater

The antibiotic-resistance profiles of Gram-negative bacteria isolated from four different sampling sites of the hospital wastewater at Lucknow city were evaluated. Of the 200 Gram-negative bacterial isolates tested, marked antibiotic resistances (over 90%) were observed for amoxicillin, methicillin, ampicillin, nalidixic acid, and penicillin depending upon the sampling sites. All Gram-negative bacterial isolates also showed multiple resistance patterns (2–13 antibiotics) in different combinations of antibiotics. The MAR index ranges were found (0.01–0.86) indicating the high risk of environmental contamination. The findings indicated that pollution of aquatic environments from different sources of the city may have a significant contribution to the emergence and dissemination of resistance in Gram-negative bacteria as well as other pathogenic bacteria in the hospital wastewater. This overuse of antibiotics as well as other pharmaceuticals in the hospital and their introduction into the aquatic environment may have a potential public health risk.

Analysis of multiple drug resistance of 2311 strains of Helicobacter pylori isolated from patients of different ages

Objective To investigate condition of single drug or multiple drug resistance and sensitivities of different combinations of antibiotics in Helicobacter pylori (H.pylori) infected patients of different ages in Jiaxing City,Zhejiang Province.Methods From January 2007 to December 2011,a total of 6280 patients underwent gastroendoscopy examination were enrolled,the average age of them was 50.8 years old.Among them,129 cases were less than 20 years old,1802 cases were between 20 and 40,3016 cases were between 40 and 60,and 1333 cases were over 60.The mucosa of gastric antrum was collected for H.pylori culture.Drug sensitivity of isolated H.pylori strains was tested with metronidazole,amoxicillin and gentamycin,furazolidone,clarithromycin and levofloxacin.x2 test was performed for the comparison of drug resistance among different age groups.Results Among 6280 specimens,H.pylori culture of 2311 cases was positive (positive rate 36.80％).The positive rate of patients aged between 40 and 60 was the highest (38.43％,1159/3016),and that of patients over 60 was the lowest (33.76％,450/1333).The drug resistance rate of metronidazole in patients between 20 and 40 years reached 98.02％ (644/657) and was the highest.The drug resistance rate of clarithromycin in patents over 60 years old was the highest,which was 22.67％(102/450).The drug resistance rates of the levofloxacin,furazolidone,amoxicillin and gentamicin were low of all ages.Mixed resistance of two antibiotic appeared in 586 strains,mixed resistance rate of metronidazole and clarithromycin was the highest (259 strains,15.23 ％).Mixed resistance of three drugs appeared in 49 strains,mixed resistance rate of metronidazole,clarithromycin and levofloxacin was the highest (32 strains,12.88％).A total of 1691 strains were sensitive to the combination of amoxicillin and gentamycin,the sensitive was rate 99.41％.The sensitive rate of the combination of amoxicillin and furazolidone,gentamycin and furazolidone was both 94.24％.Conclusions Metronidazole presented high drug resistance of all ages,and should not be chosen.The combination use of amoxicillin and gentamicin is the ideal antibiotic combination for different ages.The combination of gentamycin and furazolidone is recommended for patients who are allergic to penicillin. Key words: Helicobacter pylori ; Drug resistance, multiple, bacterial; Amoxicillin; Gentamicins; Furazolidone; Metronidazole; Drug therapy, combination; Age factors