Clinical Laboratory Standards Institute Guidelines Research Articles

Antimicrobial resistance in clinical Escherichia coli isolated from companion animals in Australia

Multidrug-resistant (MDR) Escherichia coli have become a major public health concern to both humans and animal health. While the frequency of antimicrobial resistance (AMR) in clinical E. coli is monitored regularly in human medicine, current frequency of AMR in companion animals remains unknown in Australia. In this study we conducted antimicrobial susceptibility testing (AST) and where possible, determined potential risk factors for MDR infection among 883 clinical Escherichia coli isolated from dogs (n=514), cats (n=341) and horses (n=28). AST was undertaken for 15 antimicrobial agents according to the Clinical Laboratory Standards Institute (CLSI) guidelines and interpreted using epidemiological cut-off values (ECOFFs) as well as CLSI veterinary and human clinical breakpoints. The AST revealed complete absence of resistance to carbapenems while resistance to amikacin was observed at a low level in isolates from dogs (1.6%) and cats (1.5%) compared to horses (10.7%). Among dog isolates, resistance to fluoroquinolones ranged from 9.1%–9.3% whereas among cat isolates, it ranged from 3.2%–5%. Among dog isolates, the proportion showing a 3rd generation cephalosporin (3GC) non-wild type phenotype was significantly higher (P<0.05) in skin and soft tissue infection (SSTI, n=122) isolates (17.2%–20.5%) compared to urinary tract infection (UTI, n=392) isolates (9.9%–10.2%). The frequency of multidrug resistance was 18.1%, 11.7% and 42.9% in dog, cat and horse isolates, respectively. Risk factor analysis revealed that MDR E. coli isolated from UTI were positively associated with chronicity of infection and previous antimicrobial treatment. Dogs and cats with chronic UTI that had been previously treated with antimicrobials were eight times and six times more likely to be infected with MDR E. coli compared to dogs and cats with non-chronic UTI, and no history of antimicrobial treatment, respectively. This study revealed that pre-existing disease condition and prior antimicrobial use were the major risks associated with UTI with MDR E. coli in companion animals.

COLISTIN RESISTANCE IN CARBAPENEM-RESISTANT KLEBSIELLA PNEUMONIAE STRAINS

Objective: There is an increasing use of colistin consequent to increase in the infections caused by carbapenem-resistant Klebsiella pneumoniae.The present study was conducted to determine the minimum inhibitory concentration (MIC) of colistin and the resistance pattern of colistin in carbapenem-resistant K. pneumoniae (CRKP) strains in our intensive care unit (ICU).Methods: Antibiotic susceptibility testing for other antimicrobial agents was done by Kirby-Bauer disk diffusion method. MIC of colistin was determined by agar dilution method. The results of antibiotic susceptibility testing were interpreted as per Clinical Laboratory Standard Institute guidelines 2016 and MIC of colistin were interpreted as per European Committee on Antimicrobial susceptibility testing. The carbapenem resistance was phenotypically detected by modified hodge test and imipenem/imipenem ethylenediaminetetraacetic acid disk method.Results: Out of 518 K. pneumoniae, 329 were resistant to carbapenems, and 91 isolates showed resistance to colistin. The MIC of colistin ranged between 4 and &gt;512 ug/ml and MIC90 was 16 ug/L and MIC50 was 4 ug/ml. A majority of the colistin-resistant isolates were found in multidisciplinary ICU (85/91).Conclusion: The emergence of colistin-resistant strains is a major problem due to limited treatment options for infections caused by CRKP carbapenemase producing K. pneumoniae. Colistin should not be used alone, combination therapy should be preferred.

Abstracts of Presentations Scheduled for the 10th ISNS-Asia Pacific Regional Meeting, Ulaanbataar, Mongolia, 24–26 August 2017

The International Society for Neonatal Screening (ISNS) recognises six different geographical regions [...]

Identification of Subsets of Enteroaggregative Escherichia coli Associated with Diarrheal Disease among Under 5 Years of Age Children from Rural Gambia.

.Enteroaggregative Escherichia coli (EAEC) cause acute and persistent diarrhea, mostly in children worldwide. Outbreaks of diarrhea caused by EAEC have been described, including a large outbreak caused by a Shiga toxin expressing strain. This study investigated the association of EAEC virulence factors with diarrhea in children less than 5 years. We characterized 428 EAEC strains isolated from stool samples obtained from moderate-to-severe diarrhea cases (157) and healthy controls (217) children aged 0–59 months recruited over 3 years as part of the Global Enteric Multicenter Study (GEMS) in The Gambia. Four sets of multiplex polymerase chain reaction were applied to detect 21 EAEC-virulence genes from confirmed EAEC strains that target pCVD432 (aatA) and AAIC (aaiC). In addition, Kirby-Bauer disc diffusion antimicrobial susceptibility testing was performed on 88 EAEC strains following Clinical Laboratory Standard Institute guidelines. We observed that the plasmid-encoded enterotoxin [odds ratio (OR): 6.9, 95% confidence interval (CI): 2.06–29.20, P < 0.001], aggregative adherence fimbriae/I fimbriae (aggA) [OR: 2.2, 95% CI: 1.16–4.29, P = 0.008], and hexosyltransferase (capU) [OR: 1.9, 95% CI 1.02–3.51, P = 0.028] were associated with moderate-to-severe diarrhea among children < 12 months old but not in the older age strata (> 12 months). Our data suggest that some EAEC-virulent factors have age-specific associations with moderate-to-severe diarrhea in infants. Furthermore, our study showed that 85% and 72% of EAEC strains tested were resistant to sulphamethoxazole-trimethoprim and ampicillin, respectively. Sulphamethoxazole-trimethoprim and ampicillin are among the first-line antibiotics used for the treatment of diarrhea in The Gambia.

Abstract 763: Analytical validation of Ki67/CD8 duplex IHC assay using computational tissue analysis (cTATM)

Abstract Chromogenic multiplex immunohistochemistry (IHC) assays enable investigation of the spatial relationships between tumor and immune cells, which is thought to be important for understanding and predicting therapeutic response. Development and analytical validation of multiplex IHC assays enables the use of such assays to simultaneously investigate multiple biomarkers as predictors of clinical response. In this study, we analytically validated a chromogenic duplex IHC assay that quantifies Ki67 and CD8 in formalin-fixed, paraffin-embedded non-small cell lung cancer tissues. Five performance criteria were selected and evaluated based on Clinical Laboratory Standards Institute guidelines: reportable range, analytical sensitivity, analytical specificity, accuracy, and precision. Similar to analytical validation studies for monoplex IHC assays, this study utilized a reference method and multiple days of staining. The percentage of cells positive for Ki67 nuclear staining and/or CD8 membrane staining were quantified using our computational Tissue Analysis (cTATM) platform. Performance of the Ki67/CD8 chromogenic duplex IHC assay was considered acceptable for the five criteria evaluated. Once the performance of the assay was established, additional exploratory cTA-based endpoints were examined, including the quantification of each biomarker in the tumor compartment and the tumor microenvironment, and analysis of the spatial arrangement of immune cells relative to tumor cells. In conclusion, Flagship’s cTA platform allows for more consistent quantification of individual analytes on dual-stained tissue sections, enabling investigation of complex biological questions that cannot be achieved with traditional tissue-based manual endpoints. Citation Format: Staci J. Kearney, Joshua C. Black, Benjamin J. Landis, Sally Koegler, Brooke Hirsch, Roberto Gianani. Analytical validation of Ki67/CD8 duplex IHC assay using computational tissue analysis (cTATM) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 763. doi:10.1158/1538-7445.AM2017-763

Antibiotic resistance pattern of enterococcal isolates from patients with urinary tract infection

Background: Enterococci are the most common cause of healthcare associated urinary tract infections. The frequency of isolation of Enterococci from urinary tract of hospitalized patients has risen. Enterococcus is considered as an important nosocomial pathogen because of its intrinsic as well as acquired resistance to antibiotics. The purpose of this study is to determine the emergence of Enterococci as uropathogens and their antimicrobial susceptibility pattern. Materials and methods: This cross sectional study was conducted at the Department of Microbiology, A.C.S Medical College and Hospital. A total of 175 Enterococcus spp were isolated from patients with urinary tract infection. Identification and speciation of the Enterococcal isolates were done using conventional method. The antibiotic susceptibility testing of the Enterococcal isolates was performed by modified Kirby-Bauer disk diffusion method as per Clinical Laboratory Standard Institute (CLSI) guidelines. Results: A total of 175 urine specimens yielding the growth of Enterococci were studied. Enterococcus faecalis (77.7%) was the predominant species isolated followed by E. faecium (20%) and E. durans (2.3%).The sensitivity pattern of the isolates showed an increased resistance to antibiotics like erythromycin (66.3%), ciprofloxacin (56%) and penicillin (49.7%). The HLAR (High Level Aminoglycoside Resistance) to gentamycin was observed in 37.2%, however the susceptibility rate of nitrofurantoin was 86.9%, amoxicillin - clavulanic acid was 81.1% and ampicillin (21.7%). Among the isolated Enterococci, 5.7% were vancomycin resistant. All the Enterococci were found to be sensitive to linezolid. Conclusion: Enterococci have emerged from being harmless commensals to versatile lethal pathogens. In our study, E.faecalis was the most frequently isolated species followed E.faecium . Linezolid, vancomycin, nitrofurantoin and amoxicillin-clavulanic acid were found to be the most effective antimicrobials against Enterococci isolated from patients with UTI. However vancomycin or linezolid therapy should be restricted for use in patients infected with MDR strains only. Although the frequency of isolation of VRE is not very high in our setting, this may be the beginning. Tracking of antimicrobial susceptibility due to increasing resistance rate is very important in treatment of Enterococcal infections.

Pefloxacin as a surrogate marker for quinolone susceptibility in Salmonella enterica serovars Typhi & Paratyphi A in India.

Background & objectives:The emergence of resistance to fluoroquinolones in enteric fever despite the pathogen being susceptible by in vitro laboratory results, led to repeated changes in Clinical and Laboratory Standard Institute (CLSI) guidelines for this class of antibiotics to have specific and sensitive interpretative criteria. In 2015, CLSI added pefloxacin disk diffusion criteria as a surrogate marker for fluoroquinolone susceptibility. This study was carried out to evaluate the use of pefloxacin as a surrogate marker for ciprofloxacin, ofloxacin and levofloxacin susceptibility in clinical isolates of Salmonella Typhi and S. Paratyphi A.Methods:A total of 412 strains of S. Typhi and S. Paratyphi A were studied for pefloxacin disk diffusion test as a surrogate marker for susceptibility to ciprofloxacin, ofloxacin and levofloxacin as per CLSI and the European Committee on Antimicrobial Susceptibility Testing (EUCAST) guidelines. Molecular mechanisms of resistance to fluoroquinolones were also determined and correlated with pefloxacin susceptibility breakpoints.Results:Of the total 412 strains, 34 were susceptible to ciprofloxacin and 33 each to levofloxacin and ofloxacin using CLSI minimum inhibitory concentration (MIC) breakpoints. There was a positive correlation between MICs with correlation coefficients 0.917, 0.896 and 0.958 for the association between ciprofloxacin and ofloxacin, ciprofloxacin and levofloxacin and ofloxacin and levofloxacin, respectively (P <0.001). The sensitivity, specificity and positive predictive value of pefloxacin as a surrogate marker using ciprofloxacin MIC as a gold standard were 100, 99.5 and 94.4 per cent, while 100, 99.2 and 91.7 per cent taking ofloxacin and levofloxacin MIC as gold standard. Mutations in target genes correlated with the pefloxacin susceptibility results.Interpretation & conclusions:Our results showed that pefloxacin served as a good surrogate marker for the detection of susceptibility to ciprofloxacin, ofloxacin and levofloxacin in S. Typhi and S. Paratyphi A. Further studies are required to confirm these findings.

Patterns of infections, aetiological agents and antimicrobial resistance at a tertiary care hospital in northern Tanzania.

To determine the causative agents of infections and their antimicrobial susceptibility at a tertiary care hospital in Moshi, Tanzania, to guide optimal treatment. A total of 590 specimens (stool (56), sputum (122), blood (126) and wound swabs (286)) were collected from 575 patients admitted in the medical and surgical departments. The bacterial species were determined by conventional methods, and disc diffusion was used to determine the antimicrobial susceptibility pattern of the bacterial isolates. A total of 249 (42.2%) specimens were culture-positive yielding a total of 377 isolates. A wide range of bacteria was isolated, the most predominant being Gram-negative bacteria: Proteus spp. (n = 48, 12.7%), Escherichia coli (n = 44, 11.7%), Pseudomonas spp. (n = 40, 10.6%) and Klebsiella spp (n = 38, 10.1%). Wound infections were characterised by multiple isolates (n = 293, 77.7%), with the most frequent being Proteus spp. (n = 44, 15%), Pseudomonas (n = 37, 12.6%), Staphylococcus (n = 29, 9.9%) and Klebsiella spp. (n = 28, 9.6%). All Staphylococcus aureus tested were resistant to penicillin (n = 22, 100%) and susceptible to vancomycin. Significant resistance to cephalosporins such as cefazolin (n = 62, 72.9%), ceftriaxone (n = 44, 51.8%) and ceftazidime (n = 40, 37.4%) was observed in Gram-negative bacteria, as well as resistance to cefoxitin (n = 6, 27.3%) in S. aureus. The study has revealed a wide range of causative agents, with an alarming rate of resistance to the commonly used antimicrobial agents. Furthermore, the bacterial spectrum differs from those often observed in high-income countries. This highlights the imperative of regular generation of data on aetiological agents and their antimicrobial susceptibility patterns especially in infectious disease endemic settings. The key steps would be to ensure the diagnostic capacity at a sufficient number of sites and implement structures to routinely exchange, compare, analyse and report data. Sentinel sites (hospitals) across the country (and region) should report on a representative subset of bacterial species and their susceptibility to drugs at least annually. A central organising body should collate the data and report to relevant national and international stakeholders.

Antibiotic Susceptibility Pattern of Urinary Isolates from a Tertiary Care Hospital in Kathmandu.

Urinary tract infection (UTI) is the commonest clinical condition encountered by the clinicians worldwide. The present research was conducted to find out bacterial pathogens responsible for UTI and their antimicrobial susceptibility patterns. The study was done in the Department of Microbiology, Nepalese Army Institute of Health Sciences (NAIHS), Kathmandu, Nepal. Total 450 clean catched midstream urine (MSU) samples were collected, processed, identified and their susceptibility patterns to commonly used antimicrobial agents were recorded according to the CLSI (Clinical Laboratory Standard Institute) guidelines. Out of 450 samples, 108 (24.0%) showed bacterial growth in which UTI occurred more in female with 84 isolates (77.8%) than in male 24 (22.2%). Escherichia coli was the predominant bacterial isolate and accounted for 80 (74.1%) of the total UTI cases followed by Klebsiella pneumoniae 11 (10.2%), Proteus mirabilis 5 (4.6%), Pseudomonas aeruginosa 4 (3.7%), Staphylococcus aureus 4 (3.7%), Staphylococcus saprophyticus 2 (1.9%), and Enterococcus species 2 (1.9%). The isolates were more sensitive to cefotaxim, amikacin, ofloxacin and norfloxacin. Most of the strains isolated were resistant to ampicillin, nalidixic acid, nitrofurantoin, cotrimoxazole followed by ciprofloxacin and gentamycin. The resistant patterns of urinary isolates with 3rd generation cephalosporin are increasing due to irrational and empirical use of antibiotics.

An appraisal on antibiotic susceptibility of common bacterial pathogens in urinary tract infections at a Nigerian Tertiary Health Center

Background: Urinary tract infections (UTIs) with concomitant rise in antibiotic resistance among uropathogens remained a major health problem. A periodic appraisal of the microbial agents responsible for UTIs with their antimicrobial susceptibility is, therefore, fundamental for a fitted empirical antimicrobial intervention. This study determined the range of bacterial species in patients with suspected UTI and their antibiotic susceptibility pattern at a tertiary care center in Nigeria. Patients and Methods: This was a retrospective review of urine samples subjected to microscopy, culture, and sensitivity from patients with suspected UTI in 2015. Bacterial isolates were identified by biochemical profiling. The antibiotics susceptibility of the culture-positive isolates was achieved by disk diffusion method as recommended in the Clinical Laboratory Standard Institute guidelines. Results: There were 1,096 urine samples subjected to microscopy, culture, and sensitivity during the study period; 1,001 met the inclusion criteria. Urine microscopy yielded significant pyuria in 23.2% and sterile pyuria in 8%. Urine culture was positive in 43% of the specimens and yielded Escherichia coli in 28%, Staphylococcus aureus was seen in 6.1%, and Klebsiella in 4.8%. Out of the positive cultures, 35.3% specimens have significant pyuria. The most sensitive antibiotics were Streptomycin, Ciprofloxacin, and Gentamycin. Resistance was predominantly to Nalidixic acid, Ceftriaxone, and Ampicillin. Conclusion: Periodic appraisal of the uropathogens and evaluation of their sensitivity is a needed guide in empirical antibiotic interventions. In this appraisal, E. coli was the commonest agents in patients with UTI. Most of the microbes were sensitive to Aminoglycoside and Ciprofloxacin but often resistant to Nalidixic acid and Ceftriaxone.

Prevalence of Extended Spectrum β Lactamases (ESBL) in E. coli at Al-Assad Teaching Hospital

Increasing resistance to third-generation cephalosporins amongst E. coli and Klebsiella spp. is predominantly due to the production of extended-spectrum b-lactamases (ESBLs) and when wars take place, the public health crumples and healthcare facilities can't function as it should. This study aimed to determine prevalence of ESBL production status of E coli in isolates from Patients in Al-Assad Teaching Hospital during the awful crisis in Syria. Two hundred and thirty-six E. coli isolates n=236 were collected. Antibiotic susceptibility and ESBL production were studied by disc diffusion and DDST (double disk synergy tests) according to Clinical Laboratory Standards Institute guidelines (CLSI) and EUCAST for ESBL. 75 (32%)of total isolates demonstrated MDR (multi drug resistance), 62 of resistant bacteria (26% of total) were determined as ESBL producers.

Antimicrobial efficacy of probiotic-containing toothpastes: an in vitro evaluation.

Aim To evaluate, in vitro antimicrobial ability of two probiotic toothpastes (one containing Lactobacillus paracasei, other containing Lactobacillus acidophilus) and one toothpaste without probiotic separately, and in a combination with two different mouthrinses (one containing essential oils and the other containing hexitidine). Methods Antimicrobial susceptibility was checked by using the ditch method and Clinical Laboratory Standard Institute (CLSI) guidelines. Two different toothpastes with probiotic, toothpaste without probiotic and two different mouthrinses were tested against the following selected microorganisms: Candida albicans, Candida tropicalis, Enterococcus faecalis, Streptococcus salivarius and Staphylococcus aureus. Kruskal-Wallis test and MannWhitney U test were used for the statistical analysis (p≤ 0.05). Results Probiotic toothpastes had better inhibitory effect than toothpaste without probiotic in the case of Candida albicans (p=0.043) and Streptococcus salivarius (p=0.043). In all cases, toothpastes had stronger inhibition capacity than mouthrinses (p≤0.05). Conclusion Probiotic toothpastes, as a relatively new concept in the prevention of oral infectious diseases such as caries and periodontal disease, can contribute to the prevention of oral infectious diseases.

Potency of marbofloxacin for pig pneumonia pathogens Actinobacillus pleuropneumoniae and Pasteurella multocida: Comparison of growth media

Pharmacodynamic properties of marbofloxacin were established for six isolates each of the pig respiratory tract pathogens, Actinobacillus pleuropneumoniae and Pasteurella multocida. Three in vitro indices of potency were determined; Minimum Inhibitory Concentration (MIC), Minimum Bactericidal Concentration (MBC) and Mutant Prevention Concentration (MPC). For MIC determination Clinical Laboratory Standards Institute guidelines were modified in three respects: (1) comparison was made between two growth media, an artificial broth and pig serum; (2) a high inoculum count was used to simulate heavy clinical bacteriological loads; and (3) five overlapping sets of two-fold dilutions were used to improve accuracy of determinations. Similar methods were used for MBC and MPC estimations. MIC and MPC serum:broth ratios for A. pleuropneumoniae were 0.79:1 and 0.99:1, respectively, and corresponding values for P. multocida were 1.12:1 and 1.32:1. Serum protein binding of marbofloxacin was 49%, so that fraction unbound (fu) serum MIC values were significantly lower than those predicted by correction for protein binding; fu serum:broth MIC ratios were 0.40:1 (A. pleuropneumoniae) and 0.50:1 (P. multocida). For broth, MPC:MIC ratios were 13.7:1 (A. pleuropneumoniae) and 14.2:1 (P. multocida). Corresponding ratios for serum were similar, 17.2:1 and 18.8:1, respectively. It is suggested that, for dose prediction purposes, serum data might be preferable to potency indices measured in broths.

Antimicrobial sensitivity patterns of salmonella typhi in children

Background: Enteric fever is an important public health problem in developing countries including Bangladesh. A changing antibiotic sensitivity pattern of Salmonella typhi and emergence of resistance has increased to a great concern. Objective: Aim of the study was to investigate the antibiotic sensitivity pattern of Salmonella typhi. Methods: A total of 181 Salmonella typhi samples from 5 to 15 years age group were collected from blood culture during the period of October to December 2014 from IBN SINA Hospital, Dhaka, Bangladesh. Specimens from the blood culture were identified by standard procedures as needed. Antimicrobial susceptibility testing was performed by disk diffusion method according to ‘The Clinical Laboratory Standard Institute’ guidelines. Results: Among the tested antibiotics, S. typhi was susceptible to ceftriaxone 100%, followed by cefixime and gentamicin 99.4%, ciprofloxacin 98.6%, cotrimoxazole 88.9%, azithromycin 88.4 % and least susceptible antibiotic was Ampicillin 62.5% and nalidixic acid 5%. Conclusion: The antimicrobial sensitivity testing showed that the Salmonella typhi were highly sensitive (&gt;88%) to most of the drugs used in this study, whereas nalidixic acid showed only 5% sensitivity. So this study indicates that ceftriaxone, cefixime, gentamicin and ciprofloxacin can be used as a first line therapy and nalidixic acid should be avoided for treatment.Bangladesh Journal of Medical Science Vol.15(3) 2016 p.416-418

In vitro antimicrobial susceptibility patterns of Propionibacterium acnes isolated from patients with acne vulgaris.

Propionibacterium acnes has been implicated in the development of acne vulgaris. Rampant use of topical and systemic antibiotics for acne vulgaris has led to resistance due to selective pressure. This study aimed to determine antibiotic resistance of P. acnes. A total of 102 samples were collected from acne lesions and cultured onto sheep's blood agar and brain-heart infusion agar supplemented with 5 g/L glucose and 2 mg/L furazolidone) (BHIg) under aerobic and anaerobic conditions. Species identification was done by conventional methods and the VITEK2 Compact system. The isolates were tested for penicillin, erythromycin, clindamycin, ciprofloxacin, nadifloxacin, and tetracycline by E-test, and minimum inhibitory concentration (MIC) of minocycline was determined by agar dilution on BHIg. MIC results were interpreted as per EUCAST (European Committee on Antimicrobial Susceptibility Testing) and CLSI (Clinical Laboratory Standards Institute) guidelines. P. acnes was the most common anaerobe (66%) isolated. Resistance rates using EUCAST and CLSI breakpoints were 10.6% and 6.1%, 7.6% and 0%, 7.8% and 0% for erythromycin, clindamycin, and minocycline, respectively. Tetracycline resistance was observed in 9.2% isolates irrespective of the interpretative criteria used. MIC50 and MIC90 values for nadifloxacin (0.25 and 1 µg/mL) were found to be twofold lower than those for ciprofloxacin (0.5 and 1 µg/mL). Similarly, MIC50 and MIC90 values for minocycline (0.125 and 0.5 µg/mL) were also two- to threefold lower than those for tetracycline (0.38 and 1 µg/mL). To the best of our knowledge, this is the first study focusing on P. acnes resistance from India.

Prevalence of Oxacillinase Groups I, II and III in Pseudomonas aeruginosa Isolates by Polymerase Chain Reaction and Genotyping by ERIC-PCR Methods

Background: Pseudomonas aeruginosa is main bacterial pathogen accountable for nosocomial infections. Furthermore, it could potentially become resistant to β-lactams, aminoglycosides and fluoroquinolones antibiotics. Objectives: The purpose of this study was to determine the antibiotic susceptibility pattern and genotyping of P. aeruginosa in hospitals of Tabriz (Iran) and investigate the prevalence of OXA producer isolates. Methods: Overall, 151 non-replicated isolates of P. aeruginosa were collected from October 2013 until September 2014. Antibiotic susceptibility pattern was determined by disk diffusion (Kirby Bauer) method, according to the clinical laboratory standards institute (CLSI) guideline. Genes encoding OXA (Ambler class D) β-lactamase were detected by PCR for all isolates. Polymerase chain reaction with Enterobacterial repetitive intergenic consensus-PCR (ERIC-PCR) primers was used to establish the clonal relationship between the different isolates. Results: The frequencies of resistance to antibiotics were as follows: gentamicin: 68%, ceftazidime: 67%, piperacillin: 66%, cefepime: 64%, ciprofloxacin: 62%, tobramycin: 61%, amikacin: 60%, imipenem: 52%, gatifloxacin: 28%, polymyxin B: 2 % and colistin: 2%. The OXA group I genes was identified in 82 (56%), the OXA group II gene in 26 (18%), OXA group III in 14 (9%), OXA-1 in 22 (15%) and OXA-4 in 3 (2%) isolates. The ERIC-PCR indicated high genetic diversity among P. aeruginosa isolates. Conclusions: The high prevalence of OXA β-lactamase and high genetic diversity of P. aeruginosa indicated that the resistance of P. aeruginosa might be expanding in our studied hospitals. Keywords: Antibiotic; Pseudomonas aeruginosa; Genotyping; Beta-Lactamase OXA; Polymerase Chain Reaction

Role of Non Albicans Candida Spp. and Biofilm in Neonatal ICU.

Candida spp. remains the fungal species most commonly associated with biofilm formation. Increase in Candida infections in last decades has almost paralleled the increase and wide spread use of a broad range of medical implant devices mainly in population with impaired host defences. One of the most important characteristics of biofilms is their high level of resistance to antimicrobial drugs. This study was conducted to know the prevalence of different Candida spp. causing blood stream infections and ability to form biofilm and to evaluate the co relation of biofilm with antifungal drug resistance. The present study was conducted on 12464 blood samples for the identification and speciation of various Candida spp. causing blood stream infection over a period of one year. Antifungal susceptibility was performed as per clinical laboratory standard institute guidelines and biofilm formation was detected by method described by Christensen's et al. Out of total 12464 blood culture received, 1378 (11.05%) were culture positive rest and among culture positive 100 (7.25%) Candida isolates were recovered. C. tropicalis was the commonest (43%) species followed by C. albicans (41%), C. krusei (9%) and C. parapsilosis (7%). A total of 41 Candida isolates were biofilm producers and rest 59 isolates were non-biofilm producers. A changing trend of increased prevalence of non albicans Candida spp. was observed which were resistant to commonly used antifungal fluconazole. Multi drug resistance was more common in biofilm forming Candida isolates.

Pathogens and antimicrobial susceptibility profiles in critically ill patients with bloodstream infections: a descriptive study.

Surveillance of antimicrobial resistance is vital to guiding empirical treatment of infections. Collating and reporting routine data on clinical isolate testing may offer more timely information about resistance patterns than traditional surveillance network methods. Using routine microbiology testing data collected from the Bacteremia Antibiotic Length Actually Needed for Clinical Effectiveness retrospective cohort study, we conducted a descriptive secondary analysis among critically ill patients in whom bloodstream infections had been diagnosed in 14 intensive care units (ICUs) in Canada. The participating sites were located within tertiary care teaching hospitals and represented 6 provinces and 10 cities. More than 80% of the study population was accrued from 2011-2013. We assessed the epidemiologic features of the infections and corresponding antimicrobial susceptibility profiles. Susceptibility testing was done according to Clinical Laboratory Standards Institute guidelines at accredited laboratories. A total of 1416 pathogens were isolated from 1202 patients. The most common organisms were Escherichia coli (217 isolates [15.3%]), Staphylococcus aureus (175 [12.4%]), coagulase-negative staphylococci (117 [8.3%]), Klebsiella pneumoniae (86 [6.1%]) and Streptococcus pneumoniae (85 [6.0%]). The contribution of individual pathogens varied by site. For 13 ICUs, gram-negative susceptibility rates were high for carbapenems (95.4%), tobramycin (91.2%) and piperacillin-tazobactam (90.0%); however, the proportion of specimens susceptible to these agents ranged from 75.0%-100%, 66.7%-100% and 75.0%-100%, respectively, across sites. Fewer gram-negative bacteria were susceptible to fluoroquinolones (84.5% [range 64.1%-97.2%]). A total of 145 patients (12.1%) had infections caused by highly resistant microorganisms, with significant intersite variation (range 2.6%-24.0%, χ2 = 57.50, p < 0.001). We assessed the epidemiologic features of bloodstream infections in a geographically diverse cohort of critically ill Canadian patients using routine pathogen and susceptibility data extracted from readily available microbiology testing databases. Expanding data sharing across more ICUs, with serial measurement and prompt reporting, could provide much-needed guidance for empiric treatment for patients as well as system-wide prevention methods to limit antimicrobial resistance.

Fighting the Battle With-Double Edged Weapons – A Prospective Study

Fighting the Battle With-Double Edged Weapons – A Prospective Study

Isolation, Characterization, and Antibacterial Activity of Bacteriophages Against Methicillin-Resistant Staphylococcus aureus in Pakistan.

BackgroundIn recent years, antibiotic resistance has been indicated as a paramount threat to public health. The use of bacteriophages appears to be a safer alternative for the control of bacterial infections.ObjectivesThe present study aims to explore sewage water for the presence of indigenous bacteriophages, and to investigate their antibacterial potential against Methicillin-resistant Staphylococcus aureus (MRSA).MethodsBacterial isolates were first collected and identified from pus samples taken from the surgical and burn units using standard microbiological procedures. A cefoxitin disk screen test was then used and interpreted according to the clinical laboratory standards institute (CLSI) guidelines for the detection of MRSA. The sewage samples were processed and the phages enriched using S. aureus as a host organism. Turbid and clear plaques of different sizes were isolated using an overlay method, purified, and then enumerated by means of a dilution method.ResultsThe phages exhibited good lytic activity against MRSA when tested in-vitro, and the highest activity was attained within three to six hours of phage infection. The isolated phage pq/48 was also found efficient in decreasing the bacterial count during an in-vivo trial in rabbits. A protein analysis using SDS-PAGE revealed 10 proteins of between 20 kDa and 155 kDa in size.ConclusionsThe overall results indicated that bacteriophages isolated from sewage exhibited excellent lytic activity against MRSA strains. In conclusion, bacteriophages can be further characterized and appear to be a promising candidate for phage therapy against MRSA in the future.