Susceptibility Testing Of Bacterial Isolates Research Articles

Evaluation of Quantamatrix dRASTTM system for rapid antimicrobial susceptibility testing of bacterial isolates from positive blood cultures, in comparison with commercial Micronaut broth microdilution system

Antimicrobial susceptibility testing (AST) from blood culture (BC) may take several days, limiting the eventual impact on antimicrobial stewardship. Hence, rapid AST systems represent a valuable support in shorting the time-to-response. In this work, the Quantamatrix dRASTTM system (dRAST) was evaluated for rapid AST on 100 monomicrobial BCs (50 Gram-negatives and 50 Gram-positives), including several isolates with clinically relevant resistance mechanisms. AST results were provided in 6-hours, on average. Compared to Micronaut (Merlin) system based on broth microdilution, dRAST exhibited an overall categorical agreement of 92.5 %, essential agreement of 89.0 %, and mean bias of 15.9 %. Category overestimation (potentially leading to unnecessary high-dosage treatment or to exclude active agents) and category underestimation (potentially leading to underdosing or using ineffective agents) were observed in 4.3 % and 3.1 % of cases, respectively. Even though several issues were reported, results confirmed the potential contribution of dRAST to shorten the BCs clinical microbiology workflow and management.

P16 Strengthening surveillance systems for antimicrobial resistance in urinary tract infections in Kenya

BackgroundUrinary tract infections (UTIs) are amongst the most common conditions leading to outpatient visits and are also one of the most common causes of inappropriate antibiotic usage. Addressing antimicrobial resistance (AMR) requires strengthening surveillance system in Kenya where UTI is a problem with health systems having limited capacity for accurate laboratory identification of UTI pathogens. Empirical treatment to manage UTIs is the most common problem due to limited microbiology capacity. These include shortages of suitable training, equipment, quality control procedures and professional expertise to make an accurate clinical interpretation of urine cultures. This leads to reporting normal flora as pathogens.ObjectivesTo deliver training on the identification and antibiotic susceptibility testing of bacterial isolates from urine infections at participating hospitals in the Kenyan AMR surveillance network and measure competency levels in staff participating in the training with the aim of strengthening the Kenyan surveillance system.MethodsA 1 day baseline visit to the five sites was made between October and November 2021 using a standardized checklist to assess laboratory capacity. This was followed by urine processing training conducted between November 2021 and January 2022 in Malindi, Jaramogi, Kitale, Nakuru and Nyeri County Hospitals. Training materials were developed with the input of Aga Khan University Hospital. A 5 day in-person training course was delivered at each of the five hospitals, which targeted an average of 2–3 laboratory staff per hospital. The competencies of the laboratory staff were assessed by written pre-assessment and post-assessment tests. A standardized practical assessment was achieved by use of five different control organisms. The scores were done by doing an average performance score at each hospital laboratory.ResultsOut of 13 trainees, 8 were male and 5 were female. The median number of years since qualification for these staff was 6 (IQR 2–9). The median number of total months of microbiology training time was 2.3 (IQR 1–7). The median pre-training and post-training scores were 46% and 90%, respectively; non-parametric Wilcoxon rank test showed statistical difference (P < 0.0001) between pre-training and post-training. All participants improved from pre-to post- training assessment from the 5 day training with marked improvement amongst from staff with lowest previous level of laboratory training.ConclusionsTraining microbiology staff in the accurate processing of urine sample will be an important activity for a Kenyan AMR surveillance system. These training materials, if delivered by an experienced trainer, can achieve a clear improvement in knowledge levels and practical competence for real-life microbiology identifications.

Assessment of Bacterial Contaminants and Nutritional Profiles of Mung Bean Sprouts (Vigna radiate L)

Background: Aerobic bacteria were found as contaminants in mung bean sprouts (Vigna radiate L). They are also well-known for their excellent nutritional value as well as their ease of digestion. They are rich in calories, total carbohydrates, dietary fiber, protein, macronutrients, and vitamins.&#x0D; Aim: To evaluate bacterial isolates and parameters of nutritional content of native mung bean sprouts and finally to assess the antimicrobial susceptibility testing of bacterial isolates to decide which antimicrobial agent should be utilized against certain bacterial strains.&#x0D; Methodology: Total viable bacterial isolates were enumerated by the spread plate method, and bacterial species were determined from the selected culture media with biochemical analysis. Antimicrobial susceptibility patterns were performed by the Kirby-Bauer Disk Diffusion Method and minimum inhibitory concentrations were measured using the VITEK®-2 Compact system. The nutritional composition of the sprouts was assessed using procedures suggested by the AOAC (Association of Official Analytical Chemists).&#x0D; Results: The contaminated bacterial levels were relatively lower and the higher level of total aerobic plate counts was 7.60 log10 CFU/g and 8.46 log10 CFU/g, respectively. In this study, 20 (40.8%) of mung bean sprout bacteria were lactose fermenters, such as E. cloacae complex 9 (18.4%), E. coli 8 (16.3%), and K. pneumonie 3 (6.1%), which fermented lactose to produce acidic environments that appeared as pink colonies, and 15 (30.6%) of non-lactose fermenters, namely A. baumannii 7 (14.43%) and P. aeruginosa 8 (16.3%), produced normally colorless colonies, but the rest of 14 (28.6%) were late lactose fomenters of S. marcescens grown in red-pigmented colonies in culture media. Thirteen commercially available antibiotics were used for antimicrobial susceptibility testing of bacterial isolates. Eighteen nutritional parameters were evaluated for both raw and dry sprouts.&#x0D; Conclusion: Mung bean sprouts have numerous health benefits. Because of the high number of outbreaks associated with the presence of hazardous organisms, strict safety standards must be followed.

Fatal Disseminated Pseudomonas Aeruginosa Infection in a Captive Green Iguana (Iguana iguana)

Abstract Infections with various bacteria, especially gram-negative aerobes, are a well-recognized problem in captive cold-blooded animals with immunocompromised health status, or in those kept under poor conditions. Pseudomonas is one of the most represented genera. Here, we present a case of fatal disseminated infection caused by Pseudomonas aeruginosa in a captive green iguana kept at the “Pionirska dolina” Zoo in Sarajevo, Bosnia and Herzegovina. At necropsy, severe stomatitis, pneumonia, hepatitis and nephritis, accompanied with focally extensive dermatitis were observed. Histopathology revealed multifocal necrosis in various visceral organs. Culture and subsequent MALDI-TOF MS analysis were conducted to identify the isolate as P. aeruginosa. Antimicrobial susceptibility testing revealed a wide susceptibility of the isolate, however applied therapy was instilled too late in the presented case. This case demonstrates the significance of timely and accurate identification, and antimicrobial susceptibility testing of bacterial isolates implicated in the pathology of captive reptiles. The importance of monitoring the adequate environmental conditions (enclosure temperature, humidity and conformation), health status and possible clinical signs of illness are highlighted.

Microbiology of Chronic Otitis Media and Shifting Trends of Its Antibiotic Susceptibility: A Prospective Observational Study in a Tertiary Care Institute of Western Rajasthan.

COM is a prevalent disease in lower socio-economic group mainly of a developing country. COM in active stage presents with a discharging ear. The mucopus from an active ear, when put through microbiological culture, yields a variety of aerobic and anaerobic bacteria as well As fungi. Antibiograms provide us with culture specific antibiotics. The study aims to identify prevalent microbes in our region and their sensitivity towards respective antibiotics. A total of 100 patients diagnosed with active COM in the E.N.T. outpatient department of M.D.M. Hospital, Jodhpur from July 2019 to December 2019 were enrolled. 100 swabs were obtained, one from each patient, using sterile cotton swabs and cultured for microbial flora. Antibiotic susceptibility testing of bacterial isolates was done using Kirby-Bauer disc diffusion method. The most common organism isolated were Pseudomonas spp. (58%) and Staphylococcus aureus (25%), while 8% were fungal isolates. The sensitivity pattern of Pseudomonas spp. was maximum for meropenem while that of Staphylococcus species was maximum for linezolid and vancomycin. Both were fairly sensitive to amikacin, cephalosporins and Quinolones. Culture specific antibiotics help us achieve dry ear faster and better. There is a drifting trend in antibiotic susceptibility of both aerobic and anaerobic species, towards higher group of antibiotics. Thereby suggesting emergence of multi-drug resistant strains.

Spectrum of Bacterial Colonization in Patients Hospitalized for Treatment of Multidrug-Resistant Tuberculosis.

This study investigated the bacterial colonization in patients admitted for treatment of drug-resistant tuberculosis in a specialized TB hospital. Identification and antimicrobial susceptibility testing of bacterial isolates (n = 62) from nasal, groin, and rectal swabs [patient cohort (n = 37)] were determined by the VITEK-MS system. Resistance gene analysis was by PCR and DNA sequencing. Molecular typing of Klebsiella pneumoniae isolates was by Multilocus Sequencing Typing (MLST). Patients (n = 13/37; 35%) were colonized by multidrug-resistant (MDR) bacteria (ESBL and MRSA) on admission. Of the 24 patients who were not colonized by MDR bacteria on admission, 46% (17/37) became colonized by MDR bacteria within 1 month of admission, mostly with ESBL-producing Enterobacteriales and resistance to aminoglycosides and fluoroquinolones. ESBL Escherichia coli (41/62; 66%) and K. pneumoniae (14/62; 23%) predominated. Genes encoding for ESBLs (blaCTX-M-14, blaCTX-M-15, blaSHV-28, blaOXA-1, and blaOXY-2) and plasmid-mediated quinolone resistant genes (qnrB1, qnrB4, and qnrB10) were detected. MLST revealed genetic diversity among the K. pneumoniae isolates from hospitalized patients. This study provides insight into bacterial pathogen colonization in hospitalized TB patients with the first occurrence of the qnrB4 and qnrB10 genes and co-expression of genes: qnrB4+aac(6')-lb-cr, qnrB10+aac(6')-lb-cr, qnrB4+qnrS1, and qnrB10+qnrS1 in fluoroquinolone-resistant E. coli isolates within South Africa. However, the source and colonization routes of these isolates could not be determined.

Microbiological Profile of Blood Stream Infections in Febrile Neutropenic Patients at a Tertiary Care Teaching Hospital in Rishikesh, Uttarakhand.

Context Febrile neutropenia is a serious complication of chemotherapy affecting patients with both hematological and solid malignancies, respectively. To the best of our knowledge, there is paucity of literature from Uttarakhand, India on microbiological profile of blood stream infections (BSIs) in febrile neutropenic patients. Aims The study aims to generate preliminary data on microbiological profile and antibiotic resistance pattern of BSIs in febrile neutropenic patients. Settings and Design The design involved cross-sectional study from January 1, 2019 to July 31, 2019. Methods and Materials Data of nonrepetitive paired peripheral blood samples obtained from 306 consecutive febrile neutropenic cancer patients of all age groups and both sexes, for culture and sensitivity testing, were retrospectively analyzed. All blood samples were subjected to aerobic culture using BACT/ALERT three-dimensional microbial detection system. Growth obtained in culture was identified by conventional biochemical methods. Antibiotic susceptibility testing of bacterial isolates was performed using modified Kirby Bauer disk diffusion method. Statistical Analysis Used Fisher’s exact test was used for the analysis. Results Mean age ± SD of the study population was 32.39 ± 10.56 years with a male to female ratio of 1.55:1. 74.18% of the blood samples were received from patients suffering from hematological malignancies. Microbiologically confirmed BSIs were observed in 27.1% patients. Gram-negative bacilli were predominantly isolated in culture with Klebsiella spp . being the most common. Percentage resistance values of gram-negative bacilli to aminoglycosides, β-lactam/β-lactamase inhibitor combinations, fluoroquinolones, cephalosporins, carbapenems, chloramphenicol, ampicillin, co-trimoxazole, and doxycycline were 26.6 to 91.7%, 8.3 to 86.6%, 10 to 66.7%, 13.3 to 73.3%, 8.3 to 73.3%, 80 to 93.3%, 13.3 to 20%, 16.7 to 66.6%, and 13.3 to 16.7%, respectively. Conclusion Implementation of antimicrobial stewardship program along with hospital infection control practices is needed for preventing BSIs due to MDR organisms.

Ceftriaxone-sulbactam-EDTA susceptibility profile of multi-drug resistant gram-negative bacterial isolates: Experience from a tertiary care teaching hospital in Rishikesh, Uttarakhand

Introduction: Studies have shown that ceftriaxone-sulbactam-EDTA combination is a promising therapeutic option as carbapenem sparer in cases of infections caused by ESBL and MBL producing pathogens, respectively. This study is aimed to generate preliminary data on in-vitro susceptibility profile of clinical multi-drug resistant (MDR) Gram-negative bacterial isolates to ceftriaxone-sulbactam-EDTA combination. Materials and Methods: A cross-sectional study was conducted from January 1st, 2019 to October 31st, 2019. Antibiotic susceptibility data (including that of ceftriaxone-sulbactam-EDTA combination) of 200 multi-drug-resistant Gram-negative bacterial isolates obtained from various nonrepetitive clinical samples of patients of all age groups and sexes, was retrospectively analyzed. All clinical samples were processed aerobically as per standard guidelines, and the bacterial isolates obtained in culture were identified by conventional biochemical methods. Antibiotic susceptibility testing of bacterial isolates was performed using the modified Kirby Bauer disk diffusion method, the results of which were interpreted as per the Clinical and Laboratory Standards Institute (CLSI) guidelines 2019. In vitro susceptibility test results of ceftriaxone-sulbactam-EDTA combination, disks were interpreted as per the manufacturer's instructions. Results: Acinetobacter spp. was the most common isolate (53%), followed by Escherichia coli (20.5%), Klebsiella spp. (17.5%), Pseudomonas aeruginosa (16.5%), Citrobacter spp. (2%), and Proteus spp. (1%), respectively. 99.1%, 92.7%, 88.6%, and 69.3% of Acinetobacter spp., E. coli, Klebsiella spp. and P. aeruginosa, respectively, were susceptible to ceftriaxone-sulbactam-EDTA combination disks. Conclusions: The preliminary data generated by our study could be an eye-opener for clinicians practicing in this part of the country and should prompt further investigation in the form of clinical trials.

In vitro Antimicrobial Susceptibility Testing of Bacterial Isolates Causing Wound Infection in a Tertiary Care Hospital, Port Harcourt, Nigeria

A successful treatment of wound infection is determined by the proper identification and evaluation of the varied types of microorganisms that colonize the wound surface. Such evaluation will include an antimicrobial susceptibility profiling of the invading pathogen(s) in order to implement an effective and pathogen specific treatment. The antimicrobial susceptibility profile of the bacterial species isolated from wound infections was tested to provide basis for their prudent use as antimicrobials. The standard method of antibiotic sensitivity testing with single antibiotic disc was employed in the analysis. The bacterial isolates tested were Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Klebsiella pneumoniae. The organisms were isolated from samples collected from patients at different wards at the University of Port Harcourt Teaching Hospital, Port Harcourt, Nigeria. The number and percentage occurrence of each individual bacterium encountered varied among the isolates. Pseudomonas aeruginosa has the highest frequency of occurrence of 48.6% accounting for 36 of the 74 bacterial isolates. This was followed by Staphylococcus aureus and Escherichia coli accounting for 17 (23.0%) and 11 (14.9%) respectively. Klebsiella pneumoniae was the least prevalent bacteria species accounting for 10 (13.5%) of the total bacterial count. The study shows imipenem as the most potent antimicrobial agent against the isolates tested. The isolates were moderately sensitive to gentamicin, ciprofloxacin and levofloxacin, but highly resistance to ceftazidime, erythromycin, sulphamethoxazole/trimethoprim, cefepime, amoxicillin/clavulanic acid and aztreonam. The study further reiterates the need for prudent use and control of antimicrobials.

Bacteraemia and antibiotic susceptibility pattern of isolates from patients visiting a private hospital of Kathmandu

Background: Bacteraemia can develop a broad array of complications that may be difficult to recognize initially and can increase morbidity. The study was thus conducted to identify the causative agents of bacteraemia and to assess antibiogram of the isolates among the patients suspected of blood stream infection visiting Everest hospital, New Baneshwor Kathmandu.&#x0D; Methods: Altogether 400 blood cultures were processed during March, 2015 to August, 2015. Standard Operating Procedures (SOPs) was followed during the processing of the specimens. Antibiotic susceptibility testing of bacterial isolates was done by Kirby Bauer disc diffusion method with Muller-Hinton agar using the guidelines and interpretive criteria of the Clinical and Laboratory Standards Institute (CLSI 2013).&#x0D; Result: The positivity of blood culture was found to be 48 (12%). Gram negative bacterial were found to be more predominant 27(56.2%) than gram positive bacteria 21(43.7%) in causing bacteraemia. The most prevalent isolate was Staphylococcus aureus 15 (31.2%) followed by Salmonella Paratyphi A 10 (20.8%) and Salmonella Typhi 8 (16.6%), E. coli &amp; CoNS 4 (8.3%), Pseudomonas aeruginosa 3 (6.2%) and Klebsiella pneumoniae &amp; Streptococcus pneumoniae 2 (4.1%) respectively. All gram-positive isolates were found to be sensitive to Cefoxitin, Ceftriaxone and Vancomycin followed by Ampicillin (90.42%), Erythromycin (85.71%), Ciprofloxacin (83.33%), Doxycycline (75%) and Cephalexin (70.58%) whereas gram negative isolates were sensitive to Ceftriaxone followed by Chloramphenicol (92%), Gentamicin (88.8%), Cefixime (85.71%), Ofloxacin (83.3%) and Amoxycillin and Ciprofloxacin (71.3%)&#x0D; Conclusion: The isolation of etiological agents of blood stream infection should be assessed by proper microbiological analysis and it would be helpful for controlling of the outbreaks of resistance strains through effective empirical therapy.

Microbiological airway colonization in COPD patients with severe emphysema undergoing endoscopic lung volume reduction.

BackgroundEndoscopic lung volume reduction (eLVR) is a therapeutic option for selected patients with COPD and severe emphysema. Infectious exacerbations are serious events in these vulnerable patients; hence, prophylactic antibiotics are often prescribed postinterventionally. However, data on the microbiological airway colonization at the time of eLVR are scarce, and there are no evidence-based recommendations regarding a rational antibiotic regimen.ObjectiveThe aim of this study was to perform a clinical and microbiological analysis of COPD patients with advanced emphysema undergoing eLVR with endobronchial valves at a single German University hospital, 2012–2017.Patients and methodsBronchial aspirates were obtained prior to eLVR and sent for microbiological analysis. Antimicrobial susceptibility testing of bacterial isolates was performed, and pathogen colonization was retrospectively compared with clinical parameters.ResultsAt least one potential pathogen was found in 47% (30/64) of patients. Overall, Gram-negative bacteria constituted the most frequently detected pathogens. The single most prevalent species were Haemophilus influenzae (9%), Streptococcus pneumoniae (6%), and Staphylococcus aureus (6%). No multidrug resistance was observed, and Pseudomonas aeruginosa occurred in <5% of samples. Patients without microbiological airway colonization showed more severe airflow limitation, hyperinflation, and chronic hypercapnia compared to those with detected pathogens.ConclusionMicrobiological airway colonization was frequent in patients undergoing eLVR but not directly associated with poorer functional status. Resistance testing results do not support the routine use of antipseudomonal antibiotics in these patients.

Microbiological study of otitis media

Otitis media is a destructive & persistent disease with irreversible sequelae. It is associated with bacterial or fungal aetiology. Objectives: 1) To identify bacterial isolates causing ear infection and their antibiogram. 2) To identify fungal isolates 3) To screen all smears for Acid Fast Bacilli (AFB). Materials and Methods: This study was conducted for 1 year. Pus was collected with sterile swab before commencement of antibiotics, from 98 patients of otitis media, attending ENT OPD. Gram’s staining & Gabbet’s staining (Modified ZN staining) was done for all the samples. Bacterial & fungal isolates were identified by standard methods. Antibiotic susceptibility testing of bacterial isolates was carried out by Kirby Bauer’s disc diffusion method. Results: Age of the patients studied, ranged from 2 to 68 years. Of the 98 patients, 48 were females and 50 were males. Bacterial isolates and their incidence were: Staphylococcus aureus(31%), CONS(6%), Pseudomonas species(20%), Klebsiella species(7%), Proteus species(5%). 4 fungi were isolated. 2 samples showed acid fast bacilli on Gabbet’s staining. Conclusions: The most common organisim causing Otitis media in this study was Staphylococcus aureus (MSSA). Antibiotic treatment should be individualized depending on antibiotic sensitivity report, to reduce chronicity, complications & morbidity. It also showed in the study that, doing acid fast staining routinely could be of help as it helped to diagnose two cases of pulmonary tuberculosis. Keywords: ENT- ear, nose, throat, OPD- out patient department, CONS- coagulase negative staphylococci, MSSA- methicillin sensitive staphylococcus aureus, AFB- acid fast bacilli

Vaginal infections among pregnant women at Omdurman Maternity Hospital in Khartoum, Sudan.

Microbial infections of the vagina in pregnant women are health problems that lead to serious medical complications and consequences. This study aimed to investigate and determine antimicrobial susceptibilities of the causative agents of vaginal infections in pregnant women. A cross-sectional study of pregnant women (n = 200) was conducted between August and December 2008 at Omdurman Maternity Hospital, Khartoum, Sudan. Vaginal and cervical swabs were obtained from each subject and processed for isolation and identification of pathogenic microorganisms using standard methods of wet mount preparation, direct Gram smear, Nugent scoring system, direct immunofluorescence, and cultural techniques. Antimicrobial susceptibility testing of bacterial isolates was performed using standard procedures. Statistical analysis was done using SPSS program version 12.0.1. A p value < 0.05 was considered statistically significant. Of the 200 pregnant women enrolled, BV was detected in 49.8%, followed by Chlamydia trachomatis (31.3%) and Candida albicans (16.6%), with low frequencies of Neisseria gonorrhoeae (1.8%) and Trichomonas vaginalis (0.5%). Higher infection rates were recorded among subjects in the third trimester (71.6%) than in the second trimester of gestation (28.4%). No significant association (p = 0.7) between history of abortions and C. trachomatis infections was found. Gentamicin was the most active agent against Gram-positive and Gram-negative bacteria. Clarythromycin was the most active against Mycoplasma species. Pregnant women with vaginal complaints revealed various positive microbiology results. Such cases may require specific medication. Routine culture of vaginal and cervical samples should be performed on all pregnant women during prenatal visits.

Diagnostic accuracy of a point-of-care urine bacteriologic culture test in dogs

To determine diagnostic accuracy of a compartmented bacteriologic culture and antimicrobial susceptibility testing plate (CCSP) for detection of bacterial urinary tract infection (UTI) in dogs and antimicrobial susceptibility testing of bacterial isolates. Evaluation study. 62 frozen, previously characterized bacterial isolates from canine urine cultures and 147 canine urine samples. The study was conducted in 2 phases: preliminary assay validation (phase 1) and diagnostic validation (phase 2). For phase 1, the frozen bacterial isolates were revitalized and tested with the CCSP and with standard aerobic microbiological culture (SAMC). For phase 2, the urine samples were tested with the CCSP and SAMC in parallel. For phase 1, after 24 hours of culture, 46 of 62 (74%) bacterial isolates had growth on the CCSP and all (100%) had growth in SAMC. For bacterial isolates with growth, the CCSP allowed correct identification of 45 of 46 (98%) isolates. Isolates yielding no growth on the CCSP were gram-positive cocci (Staphylococcus spp [n = 7] and Enterococcus spp [9]). In phase 2, the overall diagnostic accuracy of the CCSP, compared with SAMC, was 94% (sensitivity, 81%; specificity, 99%). The positive predictive value was 98% and negative predictive value was 92%. Susceptibility results for enrofloxacin and trimethoprim-sulfamethoxazole as determined with the CCSP had greatest concordance with those determined by SAMC (71% and 96%, respectively), compared with other antimicrobial susceptibilities. Use of the CCSP led to accurate exclusion of UTI in dogs without a UTI but was less reliable for diagnosis of UTI, particularly infections caused by gram-positive cocci. Standard aerobic microbiological culture remains the gold standard for detection of UTI in dogs.

In vitro susceptibilities of feline and canine Escherichia coli and Pseudomonas spp. isolates to ticarcillin and ticarcillin–clavulanic acid

To investigate in vitro susceptibilities of canine and feline Escherichia coli and canine Pseudomonas spp. isolates to ticarcillin and ticarcillin-clavulanic acid (T/C). In vitro susceptibility testing of bacterial isolates collected from infections. We tested 148 (83 canine and 65 feline) E. coli and 61 canine Pseudomonas spp. isolates for susceptibility to T/C using both disc diffusion and Epsilometer tests (E-tests). Additionally, susceptibilities of 96 E. coli and 23 canine Pseudomonas spp. isolates were tested via disc diffusion to ticarcillin alone. Of the E. coli isolates obtained from canine and feline urine, 92% by disc diffusion and 91% by E-tests were susceptible to T/C. Of the canine Pseudomonas isolates, 90% by disc diffusion and 82% by E-tests were susceptible to T/C. Of the Pseudomonas spp. isolates from the canine ear canal or tympanic bullae, 12% of isolates tested via disc diffusion and 23% via E-tests were found to be resistant to T/C. The 50% minimum inhibitory concentration of T/C for all feline E. coli isolates was significantly lower than that for all canine E. coli isolates (P = 0.0031). The addition of clavulanic acid significantly increased the efficacy of ticarcillin against E. coli (P< 0.0001), but had negligible effect against canine Pseudomonas spp. isolates. Ticarcillin-clavulanic acid has reasonable in vitro efficacy against canine and feline E. coli, and canine Pseudomonas spp. isolates. However, decisions to use this drug therapeutically must be made on prudent considerations to minimise selection for bacterial resistance.

Genotyping using whole-genome sequencing is a realistic alternative to surveillance based on phenotypic antimicrobial susceptibility testing

Antimicrobial susceptibility testing of bacterial isolates is essential for clinical diagnosis, to detect emerging problems and to guide empirical treatment. Current phenotypic procedures are sometimes associated with mistakes and may require further genetic testing. Whole-genome sequencing (WGS) may soon be within reach even for routine surveillance and clinical diagnostics. The aim of this study was to evaluate WGS as a routine tool for surveillance of antimicrobial resistance compared with current phenotypic procedures. Antimicrobial susceptibility tests were performed on 200 isolates originating from Danish pigs, covering four bacterial species. Genomic DNA was purified from all isolates and sequenced as paired-end reads on the Illumina platform. The web servers ResFinder and MLST (www.genomicepidemiology.org) were used to identify acquired antimicrobial resistance genes and MLST types (where MLST stands for multilocus sequence typing). ResFinder results were compared with phenotypic antimicrobial susceptibility testing results using EUCAST epidemiological cut-off values and MLST types. A total of 3051 different phenotypic tests were performed; 482 led to the categorizing of isolates as resistant and 2569 as susceptible. Seven cases of disagreement between tested and predicted susceptibility were observed, six of which were related to spectinomycin resistance in Escherichia coli. Correlation between MLST type and resistance profiles was only observed in Salmonella Typhimurium, where isolates belonging to sequence type (ST) 34 were more resistant than ST19 isolates. High concordance (99.74%) between phenotypic and predicted antimicrobial susceptibility was observed. Thus, antimicrobial resistance testing based on WGS is an alternative to conventional phenotypic methods.

Urinary tract infection in Hemodialysis patients with renal failure

Background: Urinary tract infections (UTIs) are common in dialysis patients, are associated with increased rate of complications, and may be difficult to diagnose due to often subclinical presentation.Objectives: To examine theprevalence of urinary tract infections in hemodialysis patients with renal failure, and to evaluate the diagnostic accuracy of pyuria as a screening test in hemodialysis patients.Patients and Methods: A total of forty hemodialysis patients (27 males and 13 females) with renal failure were selected according to the study criteria. Clean-catch mid-stream urine specimens were obtained from study patients, their urinalysis and bacterial culture were performed according to standard techniques. Bacteriuria is defined as detection of  105 cfu/ml of a single microorganismin culture of urine specimens.Pyuria is defined as the presence of 10 neutrophils per high power field of voided mid-stream urine.Results: Urine from 25(62%) patients had no significant organism growth, whereasurine from 15(37%) patients grew  105 cfu/ml; 6 patients had been infected with E. coli, 5 patients with Klebsiella spp., one patient with Acinetobacter, one patient with α-hemolytic Streptococci, one patient with coagulase negative Staphylococci, and one patient with Proteus spp.. Fourteenout of 40 (35%) patients had pyuria and only 9 (64%) out of 14 patients had a positive urine culture for infection. The sensitivity and specificity of pyuria screening for UTI was 60% and 80%, respectively. The positive and negative predictive values are 64% and 77%, respectively.Conclusions: The result of this study demonstrates that pyuria was a good marker for significant bacteriuria in these patients. Cultural techniques are needed for susceptibility testing of bacterial isolates to guide antimicrobial therapy. The antimicrobial susceptibility tests in this study revealed that Amikacin, Gentamicin, Ceftazidime, Cefoxitin, and Imipenem act well on isolated bacteria.

A Study on Isolation Rate and Prevalence of Drug Resistance among Microorganisms Isolated from Multiorgan Donor and Donor Corneal Rim along with a Report on Existence of bla NDM-1 among Indian Population

Purpose: To study the rate of isolation and prevalence of drug resistance among bacteria isolated from conjunctival swabs collected from multiorgan donor and Donor corneal rim specimens obtained from a tertiary eye hospital in South India.Methods: Donor corneal rims (DCR) and conjunctival swabs from multiorgan donors collected over a period of 6 months were screened for the prevalent species of bacteria and drug resistance associated with them against the first line of antibiotics by phenotypic methods and multidrug resistant isolates were further subjected for genotypic analysis.Results: Seventy-six DCR specimens were screened out of which 46 (60.5%) specimens showed bacterial growth, the predominant isolate being Coagulase negative Staphylococci, the rest 30 (39.5%) did not show any culture growth. All 42 (100%) conjunctival swabs collected from multiorgan donors were positive for bacterial culture, the prevalent species once again, being Coagulase negative Staphylococci. Among the other gram positive bacterial genus encountered were Streptococci, Bacillus, Diphtheroids and the gram negatives were Enterobacteriaceae and nonfermentors. Antibiotic resistance was significantly high among gram positive group. Seven (29.1%) gram negative isolates were positive for Extended Spectrum Beta Lactamases (ESBL’s) by conventional and molecular method. A blaNDM -1 carrying Acinetobacter baumannii was isolated from a multiorgan donor.Conclusion: Preexcision culture in multiorgan donor is necessary to prevent postoperative endophthalmitis. Preexcision culture and antibiotic susceptibility testing of bacterial isolates of DCR will aid in understanding antibiotic pattern as institution of correct antibiotic will prevent the emergence of postoperative endophthalmitis. Molecular methods help in reducing the turn-around time for understanding the drug resistance genotypes.

Prevalence of Acute Diarrhoea in Kathmandu Valley

This retrospective study was conducted during January to September in the year 1997. Three hundred and forty nine stool samples were collected from diarrhoea patients from different places of Kathmandu valley and examined at National Public Health Laboratory (NPHL), Teku, Kathmandu. Acute diarrhoea becomes epidemic in rainy season and is a major public health problem of the city. In this study, people with poor hygiene practice and poor education were infected more than other people. Among the 349 patients with the gastrointestinal disease, 26.0% were found to have bacterial infection. Out of which, 88 (25.1%), one (0.28%), one (0.28%), and one (0.28%) were found to be Vibrio cholerae 01, Vibrio cholerae 0139, Shigella dysenteriae and Escherichia coli respectively. Cholera cases were found almost throughout the year in the city though the numbers increased during the rainy season. It was highest during July (34.6%) followed by August (32.35%), September 32% and June (6.89%). The uncommon species of Vibrio i.e. Vibrio cholerae 0139 was also found in the study. Higher prevalence was found in urban areas (83.52%) than in rural areas (16.48%). Antimicrobial susceptibility testing of bacterial isolates showed that Ciprofloxacin (97.85%) was found to be the most effective antibiotic followed by Tetracycline (92.34%), Erythromycin (92.34%), Norfloxacin (93.34%), Cholramphenicol, Ampicillim, but Cotrimoxazole were found to be resistant to all isolated Vibrio cholerae.

Evaluation of the Phoenix 100 ID/AST System and NID Panel for Identification of Enterobacteriaceae , Vibrionaceae , and Commonly Isolated Nonenteric Gram-Negative Bacilli

The Phoenix 100 ID/AST system (Becton Dickinson Co., Sparks, Md.) is an automated system for the identification and antimicrobial susceptibility testing of bacterial isolates. This system with its negative identification (NID) panel was evaluated for its accuracy in the identification of 507 isolates of the family Enterobacteriaceae, 57 other nonenteric gram-negative isolates that are commonly isolated in clinical microbiology laboratories, and 138 isolates of the family Vibrionaceae. All of the isolates had been characterized by using approximately 48 conventional tube biochemicals. Of the 507 isolates of the Enterobacteriaceae, 456 (89.9%) were correctly identified to the genus and species levels. The five isolates of Proteus penneri required an off-line indole test, as suggested by the system to differentiate them from Proteus vulgaris. The identifications of 20 (3.9%) isolates were correct to the genus level but incorrect at the species level. Two (0.4%) isolates were reported as "no identification." Misidentifications to the genus and species levels occurred for 29 (5.7%) isolates of the Enterobacteriaceae. These incorrect identifications were spread over 14 different genera. The most common error was the misidentification of Salmonella species. The shortest time for a correct identification was 2 h 8 min. The longest time was 12 h 27 min, for the identification of a Serratia marcescens isolate. Of the 57 isolates of nonenteric gram-negative bacilli (Acinetobacter, Aeromonas, Burkholderia, Plesiomonas, Pseudomonas, and Stenotrophomonas spp.), 48 (84.2%) were correctly identified to the genus and species levels and 7 (12.3%) were correctly identified to the genus level but not to the species level. The average time for a correct identification was 5 h 11 min. Of the Vibrionaceae spp., 123 (89.1%) were correctly identified at the end of the initial incubation period, which averaged 4 h. Based on the findings of this study, the Phoenix 100 ID/AST system NID panel falls short of being an acceptable new method for the identification of the Enterobacteriaceae, Vibrionaceae, and gram-negative nonenteric isolates that are commonly encountered in many hospital microbiology laboratories.