Susceptibility Tests

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Current and emerging techniques for antibiotic susceptibility tests

Current and emerging techniques for antibiotic susceptibility tests

Infectious diseases caused by bacterial pathogens are a worldwide burden. Serious bacterial infection-related complications, such as sepsis, affect over a million people every year with mortality rates ranging from 30% to 50%. Crucial clinical microbiology laboratory responsibilities associated with patient management and treatment include isolating and identifying the causative bacterium and performing antibiotic susceptibility tests (ASTs), which are labor-intensive, complex, imprecise, and slow (taking days, depending on the growth rate of the pathogen). Considering the life-threatening condition of a septic patient and the increasing prevalence of antibiotic-resistant bacteria in hospitals, rapid and automated diagnostic tools are needed. This review summarizes the existing commercial AST methods and discusses some of the promising emerging AST tools that will empower humans to win the evolutionary war between microbial genes and human wits.

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Proposed quality control guidelines for antimicrobial susceptibility tests using tilmicosin

Proposed quality control guidelines for antimicrobial susceptibility tests using tilmicosin

Tilmicosin is currently used in the treatment of bovine re- spiratory disease associated with P. haemolytica and P. mul- tocida. Veterinary diagnostic laboratories frequently conduct antimicrobial susceptibility tests with tilmicosin (and other agents) against these microorganisms because they have been observed to exhibit acceptable growth in cation-adjusted Muel- ler-Hinton broth or on MHA supplemented with 5% sheep blood. However, to properly validate the susceptibility test data, the clinical laboratories require quality control guidelines for the antibiotics tested. The objective of this study was to develop such guidelines for tilmicosin by using NCCLS docu- ment M23-T2 (9) as a basis, with erythromycin as a positive control. Although this document was written for clinical mi- crobiology laboratories dealing with human pathogens and an- timicrobial agents, the same basic principles apply to the de- velopment of veterinary-use antibiotic quality control, because the in vitro testing methods are essentially identical. Four

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Impact of near field dispersion on time domain susceptibility tests

Impact of near field dispersion on time domain susceptibility tests

For susceptibility investigations using transient field sig- nals (transient susceptibility tests) a setup consisting of a high power impulse generator, a suitable impulse forming network (PFN) and an impulse radiating antenna is used. The development of new ultra wide band (UWB) sources and an- tennas has shown significant progress in the recent years. In particular, research in impulse radiating antennas (IRAs) has improved the performance of a number of other wide band systems. The development of a theoretical description of IRAs has been considered for some years. Now theoreti- cal models are available for the far field radiation of vari- ous antenna types (e.g. reflector type, TEM-horns, antenna Correspondence to: F. Sabath

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Comparative Evaluation of Laboratory Moisture Susceptibility Tests for Asphalt Mixtures in New England

Comparative Evaluation of Laboratory Moisture Susceptibility Tests for Asphalt Mixtures in New England

While the research presented in this thesis provides a starting point for determining an effective replacement for current moisture susceptibility testing in New England, further work is needed to gain a comprehensive understanding of the problem. Considering that the Hamburg wheel tracker will likely be recommended as the most promising procedure, verification work would be needed. Specifically, the connection between laboratory results and field performance seen in this research would need to be confirmed. One of the weaknesses with this research was that all of the mixtures were categorized by subjective ratings. Ideally, Hamburg results could be compared to quantitative field results (such as a measured amount of surface raveling) to confirm the findings of this research as well as ensure the laboratory results do not produce false positive results. Such a verification would provide more confidence in the recommendations of this research for the agencies considering adopting the Hamburg test.

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Microbial safety assessment of municipal water and
incidence of multi-drug resistant Proteus isolates in Rajshahi, Bangladesh

Microbial safety assessment of municipal water and incidence of multi-drug resistant Proteus isolates in Rajshahi, Bangladesh

The antimicrobial susceptibility tests were determined using the standard disc diffusion method [18]. Standardized inoculums of the overnight grown LB broth cultures were spread on Mueller-Hinton agar plates using sterile swabs. The plates were dried at room temperature for 2 hrs before placing the antibiotic disks at equidistance. The plates were incubated at 37ºC and the diameters of zone of inhibition were measured after 18 hr. The interpretation of zone diameter was followed as recommended in the CLSI [19]. A total of 12 antibiotics belonging 6 groups were used in this study. These are Penicillins: Ampicillin (AMP, 10μg), Amoxycillin (AMX, 30μg); Aminoglycosides: Streptomycin (S, 10μg), Kanamycin (K, 30μg); Tetracycline: Tetracycline (TE, 30μg), Doxycycline (DOX, 30μg); Cephalosporins: Cephradine (CE, 30μg), Ceftazidime (CAZ, 30μg), Ceftriaxone (CRO, 30μg), Cefixime (CFM, 5μg); Fluroquinolones: Ciprofloxacin (CIP, 5μg); Folate pathway inhibitors: Cotrimoxazole (Trimethoprim- Sulfamethoxazole, 25μg).

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Isolation and Identification of Bacterial and Fungal Agents in patients with Corneal Ulcer in a Tertiary Care Ophthalmic Hospital.

Isolation and Identification of Bacterial and Fungal Agents in patients with Corneal Ulcer in a Tertiary Care Ophthalmic Hospital.

The clinical and laboratory standards Institute (CLSI) subcommittee on Antifungal Susceptibility tests has developed a reproducible procedure for antifungal susceptibility testing of filamentous fungi by a broth microdilution format; the M38-A document for Filamentous fungi. It recommends the use of RPMI-1640 medium with glutamine, without bicarbonate and with phenol red as a pH indicator supplemented with 0.2% glucose and buffered to a pH of 7.0 with 0.165 mol/L MOPS (3-N- morpholino propane sulfonic acid) as used in M27– A 2 standard for yeasts.

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In vitro antimalarial drug susceptibility in Thai border areas from 1998–2003

In vitro antimalarial drug susceptibility in Thai border areas from 1998–2003

Malaria is still a major health problem in Thailand, espe- cially along the Thai-Myanmar and Thai-Cambodia bor- ders where multi-drug resistant malaria is highly prevalent [1]. Chloroquine-resistant (CQR) parasites were first reported in the late 1950s from Southeast-Asia and South- America. Since those early reports CQR has spread throughout the malaria endemic countries of the world. The Malaria Control Programme of the Ministry of Public Health of Thailand was established in 1963. The objective of the control programme is to monitor the susceptibility of Plasmodium falciparum to currently used antimalarial drugs using both in vitro and in vivo tests with the ultimate goal of providing effective malaria control strategies and delaying the emergence of drug resistance [2]. Both approaches to the sensitivity assessment have their strengths and weaknesses [3]. The in vitro sensitivity mon- itoring system is considered a suitable system for assessing absolute sensitivity without the confounding influences of host-related factors, such as host immunity and drug pharmacokinetics. The results from in vitro tests, therefore, provide a more objective insight into inherent drug sensi- tivity than do in vivo tests. However, compared to the in vivo test, there are technical requirements which make this type of analysis operationally more difficult.

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Resistance status of Aedes aegypti to insecticides in the Jazan Region of Saudi Arabia

Resistance status of Aedes aegypti to insecticides in the Jazan Region of Saudi Arabia

21. Seccacini E, Lucý´a A, Licastro S, Zerba E & Masuh H. Resistencia a temefos de Aedes aegypti (Diptera: Culicidae) en localidades del norte argentino. 5th Regional Mosquito Meeting (Argentina). Rev Biologia Acuatica, 2007; 23:48. 22. Lee, H.-L., and W. Lime. A re-evaluation of the susceptibility of field collected Aedes (Stegomyia) aegypti (Linnaeus) larvae to temephos in Malaysia. Mosq. Borne Dis. Bull. 1989; 4: 91–95.

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Current Antibiotic Resistance Trend in Clinical Isolates of Staphylococcus aureus from a Tertiary Care Hospital

Current Antibiotic Resistance Trend in Clinical Isolates of Staphylococcus aureus from a Tertiary Care Hospital

Methods: Samples of pus, blood, urine, body fluids and catheter tips submitted for culture in Microbiology department between August to September 2012, from outdoor and indoor adult patients of Pakistan Institute of Medical Sciences Islamabad, yielding growth of S. aureus were included in the study. After identification by standard methods, antibiotic susceptibility of the isolates was performed by Kirby Baeur disc diffusion method. The study was retrospective descriptive and observational.

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Accuracy and Potential Usefulness of Triplex Real Time PCR for Improving Antibiotic Treatment of Patients with Blood Cultures Showing Clustered Gram Positive Cocci on Direct Smears

Accuracy and Potential Usefulness of Triplex Real Time PCR for Improving Antibiotic Treatment of Patients with Blood Cultures Showing Clustered Gram Positive Cocci on Direct Smears

Our results showed that triplex RT-PCR would help to make early decisions that would improve the treatment of patients exhibiting a first positive BC with gram-positive cocci in clus- ters on DSE. RT-PCR results were available in less than 90 min, and the assay was both sensitive and specific, with much higher predictive values than those given by the phenotypic techniques currently used in clinical laboratories. The proper use of triplex RT-PCR results by the clinicians could have allowed better treatment of at least 31 (36%) of the 86 patients infected by S. aureus and 8 (23%) of the 35 infected by CoNS. This striking finding was due to the fact that it is often difficult to make appropriate therapeutic decisions when the first positive BC of a given patient has clustered gram-positive cocci on DSE because the currently used phenotypic tech- niques do not provide information on species identification and antibiotic susceptibility in less than 24 to 48 h. Previously, we showed that under these conditions, a time to positivity (TTP) shorter than 9 h was highly predictive of the presence of S. aureus and that a TTP longer than 18 h was predictive of the presence of CoNS (33). However, as 50% of BCs with S. aureus have a TTP longer than 9 h (33), the information supplied by the TTP is often limited. Rapid phenotypic techniques and peptide nucleic acid fluorescence in situ hybridization (28) have been developed to provide information on the staphylo- coccal species present in less than 150 to 250 min after DSE (7), without waiting for culture and identification results. How- ever, these tests provide no information on isolate susceptibil- ity to methicillin. The detection of methicillin resistance by showing the presence of the PBP2a protein by using tests designed for use with colonies grown on agar has poor sensi- tivity when these tests are used with BC bottles (8). The triplex RT-PCR we tested had none of these drawbacks, as it was highly sensitive and specific for both species identification and methicillin susceptibility determination, and produced results faster than any other method so far described.

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5.	Nazaire Aïzoun, Roseric Azondekon and  Martin Akogbéto

5. Nazaire Aïzoun, Roseric Azondekon and Martin Akogbéto

(0.05%), fenitrothion (1%), and bendiocarb (0.1%). The choice of bendiocarb was justified by its use for Indoor Residual Spraying (IRS) campaign under the financial support of the PMI (President s Malaria Initiative) in progress in the north of the country since 2011. We used fenitrothion, an organophosphate to assess cross- resistance with bendiocarb in Tanguieta district surveyed. Deltamethrin was used to check if Anopheles gambiae s.l. populations from Malanville resistance level to this product was high considering the relatively low amount of insecticide use in this area. An aspirator was used to introduce 20 to 25 unfed female mosquitoes aged 2 5 days from batch 1 into five WHO holding tubes (four tests and one control) that contained untreated papers. They were then gently blown into the exposure tubes containing the insecticide impregnated papers. After one-hour of exposure, mosquitoes were transferred back into holding tubes and provided with cotton wool moistened with a 10% honey solution. The number of mosquitoes knocked down at 60 minutes and mortalities at 24 hr post treatment were recorded following the WHO protocol (WHO, 1998).

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PHYTOCHEMICAL ANALYSIS AND ANTIMICROBIAL SCREENING OF METHANOL EXTRACT OF ANNONA MURICATA L. LEAVES

PHYTOCHEMICAL ANALYSIS AND ANTIMICROBIAL SCREENING OF METHANOL EXTRACT OF ANNONA MURICATA L. LEAVES

The antimicrobial activities (sensitivity test), zone of minimal inhibitory concentration (MIC) and minimal bactericidal (MBC) concentration of the Annona muricata extract were studied using six microorganisms: S. aureus, K. pneumoniae, S.typhi, and P.aeruginosa as bacterial isolates, and C. albicans and A.niger as fungal isolates. None of the fungal species was sensitive to the extract at concentrations of 12.5-100 mg/ml (Table 2)while all the bacterial isolates showed susceptibility with zone of inhibition ranging between 12 and 20 mm compared to the 35-37 mm for ciprofloxacin as positive control. The large zones of inhibition (Table 3) recorded for the extract signifies that the extract was considerably active and this might be due to the presence of variety of bioactive constituents in the extract such as tannins and saponins (Abo et al., 2000). Interestingly, the extract was inactive against Candida albicans and Aspergillus niger while these organism were sensitive to Econazole, meaning that the extract did not contain antifungal activity.

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DERMATOPHYTE SUSCEPTIBILITIES TO ANTIMYCOTIC DRUGS BY DISC DIFFUSION METHOD

DERMATOPHYTE SUSCEPTIBILITIES TO ANTIMYCOTIC DRUGS BY DISC DIFFUSION METHOD

Introduction: Superficial mycoses are common fungal infection of keratinized tissue. Now a day’s several option of antifungal agent are available& clinician must now choose among them. Several report of treatment failure & relapse of dermatophytosis are there. So determination of in vitro antimycotic susceptibility is essential. In our study we evaluate antifungal activity of five antimycotic agents. Material & methods: Sixty seven dermatophyte were isolated from patient having dermatophytosis . Five antimycotic discs viz. nystatin, fluconazole ,ketoconazole ,itraconazole, clotrimazole were used by disc diffusion method for in vitro susceptibility testing against these isolates. Result: A total of sixty seven dermatophytes were isolated and identified. The isolates belong to two genera and four species as follows: T. mentagrophytes 16(23.8%),T. rubrum 38(56.7%), T. violaceum 7(10.4%), M. canis 6(7.58.9%). Regarding the data, it was revealed that nystatin and itraconazole were the most effective antimycotic drugs and clotrimazole had the poorest activity. Conclusion: The disc diffusion method is a simple, reliable, inexpensive and easily adaptable assay which is more practical, simple and easier in comparison to micro dilution method.

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Characterization and monitoring of deltamethrin resistance in Anopheles culicifacies in the presence of a long lasting insecticide treated net intervention

Characterization and monitoring of deltamethrin resistance in Anopheles culicifacies in the presence of a long lasting insecticide treated net intervention

interventions, early detection and accurate information on status of insecticide resistance and underlying resist- ance mechanisms in vectors are important. The present study was conducted in 16 clusters among the abovemen- tioned 80 study clusters. The study coincided with LLIN distribution from November 2014 to January 2015. Del- tamethrin susceptibility data were generated in 16 clus- ters by WHO tube test during the pre-LLIN distribution period in 2014 (pre-LLIN survey) and two surveys were conducted: post-LLIN survey-I in March/April 2015 and post-LLIN survey-II in October/November 2015. Syner- gistic bioassays were conducted with monooxygenases, carboxylesterases and esterases specific inhibitors piper- onyl butoxide (PBO), triphenyl phosphate (TPP) and S,S,S-tributylphosphorotritioate (DEF), respectively, to explore the involvement of these detoxification enzyme families in phenotype resistance to insecticide deltame- thrin (0.05%), alpha-cypermethrin (0.01%) and mala- thion (5%). Molecular studies were performed to evaluate the association between mutations in the voltage-gated sodium channel (kdr, L1014F/S) and deltamethrin resist- ance phenotype. Previous molecular studies on An. culic- ifacies showed very low frequencies of kdr mutations [7, 8]. Biochemical-based enzyme assays were performed to detect the target insensitive acetylcholinesterase (iAChE) and detoxification enzymes esterases, and monooxy- genases activities in individual mosquitoes. Combined cytological and insecticide susceptibility studies were conducted in two seasons for detecting the prevalence of sibling species composition in An. culicifacies, a com- plex of 5 species which differ in seasonal prevalence, dis- tribution patterns, host feeding preference, and vectorial potential [9].

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<p><em>Pandoraea sputorum</em> Bacteremia In A Patient Who Had Undergone Allogeneic Liver Transplantation Plus Immunosuppressive Therapy: A Case Report</p>

<p><em>Pandoraea sputorum</em> Bacteremia In A Patient Who Had Undergone Allogeneic Liver Transplantation Plus Immunosuppressive Therapy: A Case Report</p>

and pale colonies appeared on the surface of the plates after 24 h of incubation and transformed into big, moist and ginger colonies over 48 h of incubation (Figure 1). Gram staining revealed that the isolates were gram-negative. The initial biochemical tests for the two isolates revealed positive results for oxidase reaction and nitrate reduction and negative results for urease activity, providing little information for identi fi ca- tion. In addition, the strains could not be accurately identi fi ed using the Vitek 2 gram-negative identi fi cation card, which contains 47 biochemical tests in the Vitek 2 Compact system (bio-Merieux, France), a widely used automated bacteria identi fi cation platform based on biochemical tests. 17 The reports obtained from the Vitek 2 Compact system indicated a 34% possibility of Pseudomonas fl uorescens, a 33% pos- sibility of Sphingomonas paucimobilis and a 33% possibility of Achromobacter xylosoxidans.

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High efficacy of two artemisinin based combinations: artesunate + sulfadoxine pyrimethamine and artemether lumefantrine for falciparum malaria in Yemen

High efficacy of two artemisinin based combinations: artesunate + sulfadoxine pyrimethamine and artemether lumefantrine for falciparum malaria in Yemen

Most of the early studies on anti-malarial drug efficacy that were carried out in Yemen in the 1980s and the 1990s were done in the southern parts of the country. These were mainly in vivo studies based on the standard WHO seven-day test to assess response of falciparum malaria to chloroquine (CQ). The studies, which were conducted by WHO consultants for malaria control, reported no significant levels of CQ resistance at the time [4]. In 2002, the National Malaria Control Programme (NMCP) established sentinel sites for monitoring the therapeutic efficacy of anti-malarial drugs to P. falciparum based on the earlier versions of standard WHO protocol [5]. Since then, 17 studies have been conducted by the NMCP, cov- ering CQ, sulfadoxine-pyrimethamine (SP) and amo- diaquine (AQ) monotherapy and more recently, the artemisinin-based combinations of artesunate + amodi- aquine (AS  + AQ), artesunate  + sulfadoxine-pyrimeth- amine (AS  +  SP) and artemether  +  lumefantrine (AL) (Adel Aljasary, pers. comm.). The first therapeutic tests on CQ were conducted in 2002–03 [6, 7] based on the 2001 WHO protocol [5]. By 2004, these tests revealed high rates of treatment failures with CQ and the results were summarized in WHO’s report on global monitor- ing of susceptibility of Plasmodium falciparum to anti- malarial drugs, which cited nine therapeutic efficacy studies in Yemen with median treatment failure rate of 42.4 % (range 9–57 %) for CQ and one trial for SP with no treatment failure [8].

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