Susceptibility Profiles Of Clinical Isolates Research Articles

Phenotypic characterization, detection of virulence factors, and antibacterial susceptibility profile of clinical isolates of Klebsiella pneumoniae

Klebsiella pneumoniae has been one of the most occurring bacteria in clinical samples causing community-acquired and nosocomial infections. It has been developing resistance to most antimicrobial agents. These have increased the pathogenicity and the chance for the evolvement of more invasive K. pneumoniae. The study was aimed at the identification and detection of Klebsiella pneumoniae from clinical samples. Some selected virulence factors were detected and the antibacterial susceptibility profile of the isolates was conducted. The incubation period, infective dose, and mortality rate of K.pneumoniae were measured using Baggs albino rats (BALB/c) strain. The isolation and identification of 56 Klebsiella pneumoniae from 223 clinical samples were made. Out of 56 K. pneumoniae isolates, all manifested mucoid phenotype, 44(78.6%) capsule antigen and 13(23.2%) Siderophore. The antimicrobial test conducted identified Zinacef 51(91.1%), Rocephin 50 (89.3%), and Ampiclox 50 (91.1%) as the most resistant. Ciprofloxacin 49 (87.5%), chloramphenicol 35(62.5%), Gentamycin 32(57.1%), and Amoxicillin 28 (50%) were the most susceptible to Klebsiella pneumoniae. The mouse lethality test shows that K. pneumoniae hypermucoviscous strain can cause 41.7% lethality and 66.7% mortality in Baggs Albino rats. Meanwhile an infection dose 105cfu/ml, 107cfu/ml and 109cfu/ml produced an incubation period of 9 days, 7days and 5days. The chi-square test shows no significant association between the isolate and the gender of the patients, but there is a significant association between the samples and isolates identified p <0.05. Likewise, the association between mucoid phenotype, capsule antigen, siderophore, and the type of infection is significant (p<0.05). It is finally concluded that K. pneumoniae is the second most prevailing bacterium causing community-acquired infection the resistant pattern recorded identified the test bacteria as a multidrug-resistant strain and manifestation of the virulent factor depends on the type and site of infection caused by the K. pneumoniae.

In vitro Susceptibility of Nontuberculous Mycobacteria to Tedizolid.

ObjectiveNontuberculous mycobacteria (NTM) can cause pulmonary and extrapulmonary diseases. Tedizolid (TZD) is a new oxazolidinone with in vitro activity against NTM such as Mycobacterium avium complex (MAC), Mycobacterium fortuitum, and Mycobacterium abscessus complex. The aim of this study was to evaluate the TZD susceptibility profiles of clinical isolates of NTM.MethodsThe microdilution method was used to identify the minimum inhibitory concentration (MIC) of TZD and linezolid (LZD) for 133 clinical NTM isolates. Broth microdilution chequerboard assays were used to investigate the synergistic effects of TZD and three antibiotics on two reference isolates and eleven clinical isolates of NTM.ResultsThe TZD MIC50 and MIC90 for M. abscessus complex were 2 and 4 μg/mL, 16 and >32 μg/mL for MAC, respectively. TZD exhibited lower MICs than that of LZD for most NTM, which were positively correlated. Due to the high MIC values of TZD against MAC, it is necessary to conduct drug sensitivity tests before TZD administration. TZD-clarithromycin combination had synergistic response on M. abscessus complex in 3 of the 8 isolates, which lasted only 3–5 days. TZD-cefoxitin had synergistic effect against all five M. fortuitum isolates.ConclusionOur study demonstrates that TZD had greater in vitro potency than LZD, and synergy studies suggested that TZD may be an important component of multi-drug treatment regimen.

Bacterial Isolates and Their Antibiotic Susceptibility Pattern among Patients with Infected Wounds Admited in Orthopaedic and Trauma Ward in Tertiary Care Hospital North-Eastern Tanzania

The hospital environment contributes to wound infections. Effects of such infections include prolonged hospitalization, increased morbidity, potential for antibiotics resistance and mortality due to sepsis. An updated knowledge of antibiotics susceptibility profiles of clinical isolates will assist both in choosing the most appropriate antibiotic treatment for wound infections and help in curbing the escalation of drug resistance. Cross sectional hospital based study, analysis of 125 pus samples collected from January 2018 to December 2020 was conducted. Identification and characterization of isolates were performed on the basis of Gram staining, microscopic characteristics, colony characteristic, and biochemical tests using standard microbiological methods. Antibiotic susceptibilities of bacterial isolates were determined by Kirby Bauer disc diffusion. A total of 125 pus samples were studied, 94 (75%) were from male patients, mean age was 38.5 (SD ± 19) years. Single bacterial isolates were recovered from 120 (96%) samples, 67 (53.6%) shows Multiple Drug Resistance (MDR) pattern, 74 (59.2%) were gram negative, the predominant organism isolated was Staphylococcus aureus 46 (36.8%). Gram negative isolates showed high resistance to ampicillin and cephalosporins. Gram positive isolates showed high resistance to erythromycin. Both gram positive and negative were found to be highly susceptible to gentamicin, amikacin, clindamycin, ciprofloxacin and amoxicillin/clavulanic acid. The study showed that Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli are the major bacteria isolated from pus samples. High proportion (53.6%) of the isolates was MDR. In the light of these findings, a change in antibiotic prescription policy is required at this hospital.

Structural insights into the inhibition of bacterial RecA by naphthalene polysulfonated compounds.

SummaryAs a promising target for alternative antimicrobials, bacterial recombinase A (RecA) protein has attracted much attention for its roles in antibiotic-driven SOS response and mutagenesis. Naphthalene polysulfonated compounds (NPS) such as suramin have previously been explored as antibiotic adjuvants targeting RecA, although the underlying structural bases for RecA-ligand interactions remain obscure. Based on our in silico predictions and documented activity of NPS in vitro, we conclude that the analyzed NPS likely interact with Tyr103 (Y103) and other key residues in the ATPase activity center (pocket A). For validation, we generated recombinant RecA proteins (wild-type versus Y103 mutant) to determine the binding affinities for RecA protein interactions with suramin and underexamined NPS in isothermal titration calorimetry. The corresponding dissociation constants (Kd) ranged from 11.5 to 18.8 μM, and Y103 was experimentally shown to be critical to RecA-NPS interactions.

Characterization of non albicans candida species and the antifungal susceptibility profile of clinical isolates

Introduction and Objectives: Antibiotics, immunodeficiencies and advances in medical practices have all contributed to increased incidence in fungal infections. In recent times Non albicans Candida species are increasingly being isolated from clinical specimens. The present study was aimed at the characterization and antifungal susceptibility of Non albicans Candida species from clinical specimens received in Microbiology Laboratory for one year from June 2015–May 2016. Materials and Methods: A total of 181 Non albicans Candida isolates were included in the study. Candida was identified from clinical samples by gram stain, culture on Saboraud’s Dextrose Agar (SDA) and germ tube test. The organisms were further speciated by cornmeal agar morphology, sugar assimilation and fermentation tests and growth on CHROM agar (Himedia). Antifungal sensitivity was performed by using disc diffusion method as per CLSI guidelines. Results: The most common isolate was Candida tropicalis (59.11%) followed by C.glabrata (28.18%), C.parapsilosis (8.83%) and C.krusei (3.88%). Highest number of isolates were from urine (74/181). Resistance to Fluconazole in clinical isolates of C.tropicalis has increased. C.krusei was the most resistant species. Conclusion: Use of CHROM agar is rapid, simple and cost effective compared to time consuming technically demanding expensive conventional methods. Antifungal susceptibility testing has to be carried out before starting therapy because of varying susceptibility pattern in different species of Candida. Keywords: Non albicans Candida species, Candidiasis, CHROM agar.

Antibiotic Susceptibility Pattern of Escherichia coli Isolated from Various Clinical Samples in Duhok City, Kurdistan Region of Iraq

Background: Escherichia coli (E. coli) is one of the most common causative agents of bacterial infections. The emergence of multidrug-resistant E. coli is a major public health threat worldwide. Objectives: This study aimed to determine the antibiotic susceptibility profile of clinical isolates of E. coli from different samples. Methods: A total number of 454 clinical samples, including urine, wound, cervical swab, blood, semen, ascetic, and cerebral spinal fluid samples were collected from patients between January 2017 and February 2020. Then, E. coli was confirmed and susceptibility to different antibiotics was determined using the Vitek-2 compact system. Results: Escherichia coli isolates were more frequent in females (70.7%) than in males (29.3%). In the case of urine samples, E. coli was found to be highly susceptible to ertapenem (97.6%) and imipenem (96.4%) but resistant to ampicillin (87.8%). For wound and cervical swabs, E. coli was 100% resistant to ampicillin and cefepime but 100% sensitive to ertapenem and imipenem. It was found that E. coli isolates from blood samples were 100% resistant to ampicillin, ceftriaxone, and cefoxitin, and around 75% of them were sensitive to ertapenem, ciprofloxacin, and levofloxacin. Finally, E. coli isolated from other clinical samples were highly sensitive to ertapenem, imipenem, levofloxacin, nitrofurantoin, and cefazolin. Conclusions: Escherichia coli isolated from various clinical specimens showed differences in antibiotic sensitivity patterns, with high resistance to commonly used antibiotics. The most effective antibiotics against E. coli isolates were ertapenem, imipenem, and nitrofurantoin. However, the clinical isolates of E. coli displayed high resistance rates to ampicillin, ceftriaxone, and cefepime. Therefore, it is proposed to perform antibiotic sensitivity testing by physicians to select the most effective antibiotics.

A five-year retrospective study shows increasing rates of antimicrobial drug resistance in Cabo Verde for both Staphylococcus aureus and Escherichia coli

Objectives: Data on baseline drug resistance important in informing future antimicrobial stewardship programs. So far, no data on the antimicrobial drug resistance of clinical isolates available for the African archipelago of Cabo Verde.Methods: We performed a retrospective analysis over years (2013-17) of the drug susceptibility profiles of clinical isolates in the two main hospitals of Cabo Verde. For Escherichia coli and Staphylococcus aureus, representing 47% and 26% of all clinical isolates, the antimicrobial drug resistance profile was reported for six representative drugs.Results: For E. coli we detected an increase in resistance to ampicillin, amoxicillin/clavulanic acid, ceftriaxone, ciprofloxacin and trimethoprim-and for S. aureus to methicillin, erythromycin and trimethoprim-sulfamethoxazole. This increase in both the most commonly isolated bacterial pathogens is alarm as it might compromise empirical treatment in a setting with limited access to laboratory testing.Conclusions: When compared to the published low resistance rates in carriage isolates, the more alarming situation in clinical isolates for S. aureus might encourage antimicrobial stewardship programs to reduce in hospital settings, possibly as part of the Cabo Verdean national plan against antimicrobial drug resistance.

Rapid Emergence of Multidrug-Resistance among Gram Negative Isolates at a Tertiary Pediatric and Maternity Hospital in Ulaanbaatar, Mongolia.

Introduction:Information on microbiological and susceptibility profiles of clinical isolates in Mongolia is scarce, hampering infection control and clinical care.Methods:Species and resistance profiles of 6334 clinical gram negative isolates, collected at Mongolia's National Center for Maternal and Child Health between 2014 and 2017 were analyzed.Results:Annual proportion of multidrug-resistance among E. coli and Enterobacter isolates increased from 2.8% to 16.6% and 3.5% to 22.6% respectively; Klebsiella isolates exhibiting susceptibilities suggestive of extended spectrum beta-lactamase (ESBL) production from 73% to 94%. By 2017, 60.6% of Klebsiella isolates were multidrug-resistant, most originated from intensive care wards. Enterobacteriaceae exhibiting susceptibility patterns suggestive of ESBL production and multidrug-resistant organisms were common and their incidence increased rapidly.Conclusion:These findings will serve to build strategies to strengthen microbiological surveillance, diagnostics and infection control; and to develop empiric therapy and stewardship recommendations for Mongolia's largest Children's and Maternity hospital.

Molecular Characteristics and Antimicrobial Susceptibility Profiles of Elizabethkingia Clinical Isolates in Shanghai, China.

PurposeTo investigate molecular characteristics and antimicrobial susceptibility profiles of clinical isolates of Elizabethkingia in Shanghai, China.MethodsElizabethkingia isolates were collected in a university-affiliated hospital in 2012–2015 and 2017–2018. They were re-identified to species level by 16S rRNA gene and species-specific gene sequencing. Antimicrobial susceptibility testing, screening for metallo-beta-lactamase production, identification of antimicrobial resistance genes and pulsed-field gel electrophoresis (PFGE) were performed.ResultsAmong 52 Elizabethkingia isolates, E. anophelis was the most prevalent species (67.3%), followed by E. meningoseptica (26.9%). High carriage rates of blaCME, blaBlaB and blaGOB genes were consistent with the poor in vitro activity of most β-lactams including carbapenems. Nevertheless, β-lactamase inhibitors increased susceptibility rates significantly for cefoperazone and piperacillin. Susceptibility rates for minocycline, tigecycline, rifampin and levofloxacin were 100%, 78.8%, 76.9% and 71.2%, respectively. Ser83Ile or Ser83Arg substitution in the DNA gyrase A unit was associated with resistance to fluoroquinolones. MIC50/MIC90 values of vancomycin and linezolid were 16/16 mg/L and 16/32 mg/L, respectively. Molecular typing showed twenty-one different types of PFGE and more than one indistinguishable isolates were observed in each of the eight subtypes.ConclusionTetracyclines, tigecycline, β-lactam/β-lactamase inhibitor combinations, rifampin and fluoroquinolones demonstrated high rates of in vitro activity against clinical isolates of Elizabethkingia. Both genetic diversity and clonality were observed from this health-care facility. Our report provides potential alternative treatment options for Elizabethkingia infections.

Tigecycline and inducible clindamycin resistance in clinical isolates of methicillin-resistant Staphylococcus aureus from Terengganu, Malaysia.

The spread of multidrug-resistant Staphylococcus aureus is a public health concern. The inducible macrolide-lincosamide-streptogrammin B (iMLSB ) phenotype (or inducible clindamycin resistance) is associated with false clindamycin susceptibility in routine laboratory testing and may lead to treatment failure. Tigecycline resistance remains rare in S. aureus worldwide. This study aims to determine the antimicrobial susceptibility profiles of clinical isolates of S. aureus obtained from the main tertiary hospital in Terengganu state, Malaysia, from July 2016 to June 2017. The antimicrobial susceptibilities of 90 methicillin-resistant S. aureus (MRSA) and 109 methicillin-susceptible S. aureus (MSSA) isolates were determined by disc diffusion with the iMLSB phenotype determined by D-test. Multidrug resistance (MDR) and the iMLSB phenotype were more prevalent in MRSA (84.4 and 46.7 %, respectively) compared to MSSA isolates. All five tigecycline-resistant isolates were MRSA. The high incidence of MDR and the iMLSB phenotype and the emergence of tigecycline resistance in the Terengganu S. aureus isolates warrants continuous vigilance.

In Vitro Susceptibility of Mycobacterium abscessus and Mycobacterium fortuitum Isolates to 30 Antibiotics.

Objective Nontuberculous mycobacteria (NTM) cause various diseases in humans and animals. Recently, the prevalence of NTM-related disease has been on the rise, becoming an emerging public health problem. The aim of this study was to determine the antibiotic susceptibility profiles of clinical isolates of Mycobacterium abscessus and Mycobacterium fortuitum. Methods. We performed susceptibility tests on 37 clinical NTM isolates to 30 antibiotics with the microdilution method recommended by the Clinical and Laboratory Standards Institute. Results Both M. abscessus and M. fortuitum were highly resistant to antitubercular drugs such as isoniazid, rifampin, ethambutol, clofazimine, ethionamide, and rifabutin. M. abscessus showed the lowest resistant rates to cefoxitin (10%), azithromycin (10%), amikacin (10%), and clarithromycin (20%) and very high resistant to sulfamethoxazole, vancomycin, oxacillin, clindamycin, and all fluoroquinolones. M. fortuitum showed low resistance to tigecycline (0%), tetracycline (0%), cefmetazole (12%), imipenem (12%), linezolid (18%), and the aminoglycosides amikacin (0%), tobramycin (0%), neomycin (0%), and gentamycin (24%). ConclusionAmikacin, cefoxitin, and azithromycin have the highest in vitro activity against M. abscessus. Isolates of M. fortuitum need to be individually evaluated for drug susceptibility before choosing an effective antimicrobial regimen for treatment of infections.

Isolation rate and antimicrobial susceptibility profiles of Mycoplasma mycoides subspecies capri field isolates from sheep and goats in Pakistan

Mycoplasmosis, the respiratory infection, is a well-established cause of heavy economic losses in sheep and goats farming. The occurrence and antibiotics susceptibility profiles of clinical isolates of Mycoplasma mycoides subsp. capri (Mmc) from suspected cases of contagious caprine pleuropneumonia (CCPP) were investigated in small ruminants of three climatic- southern, central and northern- regions of Khyber Pakhtunkhwa province of Pakistan. Specie specific-PCR for Mmc confirmed 24% (198/825) isolates with significantly (P˂0.001) higher number (83/275; 30.18%) recovered from the northern-, followed by southern- (68/275; 24.73%) and central-regions (47/275; 17.09%), respectively. Subsequently, a total of 54 PCR-confirmed isolates (18 from each zone) were subjected to antibiogram assay. Five different common antimicrobial agents including ceftiofur, enrofloxacin, gentamycin, oxytetracycline and tylosin were tested by disc diffusion and broth microdilution methods The antibiotic susceptibility profiles of Mmc isolates indicated that enrofloxacin exhibited the highest (P˂0.001) in vitro antibacterial activity with a maximum zone of inhibition (19±0.71mm) and the lowest MIC (0.001±0.0002mg/mL) amongst the tested antimicrobial agents, followed by gentamycin (11±0.45mm and 0.01±0.001mg/mL zone of inhibition and MIC, respectively). All these isolates were found resistant against tylosin, oxytetracycline and ceftiofur sodium: antibiotics that are favored in clinical cases of CCPP. This study concludes a high occurrence of Mmc in small ruminants during infection of CCPP, and increased resistance rate against commonly used antibiotics.

In vitro susceptibility of Sporothrix brasiliensis: Comparison of yeast and mycelial phases.

Sporothrix brasiliensis has emerged as an important cause of sporotrichosis, particularly associated with feline and zoonotic cases. Owing to the paucity of data on antifungal activity against this species, the present study aimed to evaluate the in vitro susceptibility of clinical isolates of S. brasiliensis in the mycelial and yeast phases to itraconazole (ITZ), terbinafine (TRB), and amphotericin B (AMB). Thirty-five isolates from an outbreak of feline sporotrichosis in Southern Brazil were used. All of them were assessed in the yeast and filamentous phases using the broth microdilution technique in accordance with the respective reference protocols M27-A3 and M38-A2 of the Clinical and Laboratory Standards Institute (CLSI). In our study, TRB was the most active antifungal against both the filamentous and yeast phases, showing GM of the MIC of 0.343μg/ml and 0.127μg/ml, respectively. In the yeast phase, the GM of the MIC for TRB was significantly lower than that for both ITZ (P = .009) and AMB (P < .001). However, in the filamentous phase, the GM of the MIC for TRB was significantly lower than that of AMB (P < .001), but not different from that of ITZ (P = .091). AMB was the antifungal with the highest GM of the MIC for both phases (1.486μg/ml for the filamentous phase and 0.660μg/ml for the yeast). Our results may contribute to a better understanding of antifungal susceptibility profiles of clinical isolates of S. brasiliensis in the mycelial and yeast phases in further studies.

Biofilm Formation and Antibiotic Susceptibility Profile of Clinical Isolates of Staphylococcus aureus Isolated from Clinical Samples in Zaria, Nigeria

Background: Staphylococcus aureus is one of the common pathogens associated with nosocomial as well as community acquired infections due to its ability to form biofilms. Research aim: The aim of this study was to observe the biofilm forming abilities and to study the antibiotic susceptibility profile of clinical isolates of S. aureus. Methodology: A total of 56 isolates from clinical samples were identified using standard techniques and the isolates were further tested for biofilm formation, using microtiter plate assay and antibiotic susceptibility testing was carried out using Kirby-Bauer method. Results: The results showed that out of the 56 S. aureus isolated, biofilm formation was observed in 27 (48.2%). Strong biofilm formation was observed in 5.4% (3) of the isolates, moderate biofilm formation in 8.9% (5) of the isolates, weak biofilm formation in 33.9% (19) of the isolates, while 51.8% (29) of the isolates were non-biofilm formers. Prevalence of S. aureus infection was higher in females (67.9%) compared to males (32.1%). The isolates were highly susceptible to Gentamicin (100%), Tigecycline (98.21%), Sulphamethoxazole-Trimethoprim (89.29%), Ciprofloxacin (89.29%) and Linezolide (75%), while the isolates showed low susceptibility to Erythromycin (28.55%), Clindamycin (35.71%) and Vancomycin (41.07%). None of the isolates showed inducible Clindamycin resistance phenotypically. 9 (16.67%) of the isolates showed constitutive phenotype, 3 (5.36%) showed Methicillin-Sensitive (MS) phenotype while 44 (78.57%) showed none of the above phenotypes. Conclusion: Clinical isolates of S. aureus have the potential of producing biofilm and this could influence the rate of resistance.

Characterisation of Antimicrobial Resistance in Salmonellae during 2014–2015 from Four Centres Across India: An ICMR Antimicrobial Resistance Surveillance Network Report

Purpose: The main purpose of this study was to establish ‘Antimicrobial Resistance Surveillance Network’ in India and to monitor the antimicrobial susceptibility profile of clinical isolates to establish a national network across the country for monitoring antimicrobial resistance in Salmonella. MaterialsandMethods: This study was conducted at All India Institute of Medical Sciences, nodal centre with clinical isolates of Salmonellae collected from four centres across India, which included Christian Medical College, Vellore; Postgraduate Institute of Medical Education and Research, Chandigarh and Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry. Total 20% of the selected strains from each centre were characterised for molecular studies which included molecular mechanism of fluoroquinolones resistance and multiple locus sequence type. Results: A total of 622 Salmonellae were received from all centres during January 2014 to December 2015. Out of these 622 isolates, 380 were Salmonella Typhi, 162 were Salmonella Paratyphi A and 7 were S. Paratyphi B isolated from blood and 73 were other Salmonella serotypes. Multiple drug resistance (resistant to ampicillin, chloramphenicol and co-trimoxazole) was less than 3% in S. Typhi. In S. Paratyphi A, chloramphenicol and co-trimoxazole susceptibility was 100% and 99%, respectively, whereas ampicillin susceptibility was 86% (139/161). Ciprofloxacin and nalidixic acid susceptibility was 15% (24/162) and 1% (2/162) from all centres. S. Paratyphi B was isolated from 7 patients. All isolates were third-generation cephalosporin sensitive. The most common mutations found were at codon 83 and at codon 87. We did not find any mutation in acrR gene. Efflux pump and qnr genes were not found in any isolate tested. All 86 S. Typhi isolates clustered into two sequence types - ST1 and ST2. Out of these 86 isolates, 70 S. Typhi were ST1 and 16 were ST2. All S. Paratyphi A was clustered in ST85 and ST129 on the basis of mutation in sucA gene. Out of 27 S. Paratyphi A, 13 were grouped into ST85 and 14 were grouped into ST129. Conclusions: Enteric fever is one such infection which poses challenges in antimicrobial resistance. Hence, continuous surveillance is important to track bacterial resistance and to treat infections in a cost-effective manner.

Candida haemulonii complex: species identification and antifungal susceptibility profiles of clinical isolates from Brazil.

The emerging fungal pathogens comprising the Candida haemulonii complex (Candida haemulonii, Candida haemulonii var. vulnera and Candida duobushaemulonii) are notable for their antifungal resistance. Twelve isolates with phenotypic similarity to C. haemulonii were recovered from patients in Brazilian hospitals. Here we aimed to identify these isolates by a molecular approach, using the current classification of this fungal complex, and to evaluate their antifungal susceptibility profiles. The fungal isolates were rechecked to certify their authentication by mycology methodologies and then characterized by ITS1-5.8S-ITS2 gene sequencing. A susceptibility assay was performed using the broth microdilution method published by CLSI (M27-A3/M27-S3). Based on biochemical tests, all Brazilian isolates were identified as C. haemulonii. After employing ITS sequencing, five isolates were identified as C. haemulonii, four as C. duobushaemulonii and three as C. haemulonii var. vulnera. All 12 clinical isolates were resistant to amphotericin B (MICs ranged from 2 to >16 mg/L) and fluconazole (MICs ≥ 64 mg/L). One isolate of C. haemulonii var. vulnera and two isolates of C. duobushaemulonii were susceptible-dose dependent to itraconazole, while the remaining isolates (75%) were resistant to this antifungal. Eight out of 12 isolates (66.7%) were resistant to voriconazole (MICs ≥ 16 mg/L), while all isolates were susceptible to caspofungin (MICs ≤ 0.5 mg/L). Our results reinforce the importance of molecular identification in differentiating species of the C. haemulonii complex. Moreover, the antifungal multiresistant profile of clinical isolates of the C. haemulonii complex represents a challenge to the treatment of such infections.

In vivo assessment of drug efficacy against Mycobacterium abscessus using the embryonic zebrafish test system.

Mycobacterium abscessus is responsible for a wide spectrum of clinical syndromes and is one of the most intrinsically drug-resistant mycobacterial species. Recent evaluation of the in vivo therapeutic efficacy of the few potentially active antibiotics against M. abscessus was essentially performed using immunocompromised mice. Herein, we assessed the feasibility and sensitivity of fluorescence imaging for monitoring the in vivo activity of drugs against acute M. abscessus infection using zebrafish embryos. A protocol was developed where clarithromycin and imipenem were directly added to water containing fluorescent M. abscessus-infected embryos in a 96-well plate format. The status of the infection with increasing drug concentrations was visualized on a spatiotemporal level. Drug efficacy was assessed quantitatively by measuring the index of protection, the bacterial burden (CFU), and the number of abscesses through fluorescence measurements. Both drugs were active in infected embryos and were capable of significantly increasing embryo survival in a dose-dependent manner. Protection from bacterial killing correlated with restricted mycobacterial growth in the drug-treated larvae and with reduced pathophysiological symptoms, such as the number of abscesses within the brain. In conclusion, we present here a new and efficient method for testing and compare the in vivo activity of two clinically relevant drugs based on a fluorescent reporter strain in zebrafish embryos. This approach could be used for rapid determination of the in vivo drug susceptibility profile of clinical isolates and to assess the preclinical efficacy of new compounds against M. abscessus.

Antibiotic susceptibility profiles of clinical isolates of Acinetobacter species isolated from Selayang hospital, Malaysia

Antibiotic susceptibility profiles of clinical isolates of Acinetobacter species isolated from Selayang hospital, Malaysia

Determination of antifungal susceptibility patterns among the clinical isolates of Candida species

Context:Candida species are opportunistic yeasts that cause infections ranging from simple dermatosis to potentially life-threatening fungemia. The emergence of resistance to antifungal drugs has been increased in the past two decades.Aim:the present study we determined to find out the susceptibility profiles of clinical isolates of Candida species against four antifungal drugs, including amphotericin B, ketoconazole, fluconazole and itraconazole.Materials and Methods:Antifungal susceptibility testing of the yeasts was done in accordance with the proposed guidelines for antifungal disk diffusion susceptibility testing of yeasts based on the CLSI document M44-A.Results:A total of 206 yeast isolates were assessed. Among the evaluated Candida species, the highest rates of resistance to ketoconazole were seen in Candida glabrata (16.6%) and Candida albicans (3.2%). Susceptibility and intermediate response to fluconazole were seen in 96.6% and 3.4% of the Candida isolates, respectively. A total of 19 (9.2%) yeast isolates showed petite phenomenon including 11 C. glabrata, 3 C. albicans, 2 Candida dubliniensis and one isolate of each Candida krusei and Candida parapsilosis.Conclusion:The high number of petite mutation in the isolated yeasts should be seriously considered since it may be one of the reasons of antifungal treatment failure.

Predominance of multi-drug-resistant LAM and Beijing family strains among Mycobacterium tuberculosis isolates recovered from prison inmates in Tula Region, Russia

The genotypic characteristics and drug susceptibility profiles of clinical isolates of Mycobacterium tuberculosis recovered from prison hospital patients in the Tula region (central Russia) during 2001 and 2002 are reported. The emergence of multi-drug-resistant tuberculosis (TB) poses a major health risk to the population, with economic implications for TB control. Prisons serve as a continuous source of TB transmission. The results showed that members of the LAM and Beijing families are major contributors to the epidemiological picture of TB in the population studied. The two families of strains accounted for most of the drug-resistant TB in the population. The genotypic characteristics of the M. tuberculosis predominant LAM strain that was responsible for 31 % of TB cases in this setting are presented.