Fluconazole-resistant Candida parapsilosis complex candidemia and analysis of mutations in the ERG11 gene from Pakistan.

BACKGROUND: Recent reports of the emergence of fluconazole resistance in Candida parapsilosis species complex poses a challenge, more specifically in settings where echinocandin-based treatment regime is not feasible. OBJECTIVE: This study reported emergence of fluconazole resistance in C. parapsilosis species complex strains isolated from blood cultures. MATERIALS AND METHODS: This retrospective observational study was conducted from 2018 to 2020 at a tertiary care laboratory from Pakistan. Fluconazole-resistant C. parapsilosis species complex fungemia cases were identified from laboratory database and clinical details were collected. Identification of C. parapsilosis species complex was done using API 20C AUX and Cornmeal Tween80 agar morphology. Minimum inhibitory concentrations (MICs) were determined using Sensititre YeastONE and interpretation was done with CLSI M60 ED1:2017. ERG11 gene region was amplified and sequenced by Sanger sequencing and analysed by MEGA 11 Software. RESULTS: A total of 13 (8.5%) fluconazole-resistant isolates were identified from 152 C. parapsilosis species complex candidemia cases. Fluconazole MICs of resistant isolates ranged between 8 and 256 µg/mL. Analysis of ERG11 gene revealed nonsynonymous mutations at position Y132F in 86% of the fluconazole-resistant isolates. Diabetes and hospitalization were important risk factors for candidemia with fluconazole-resistant C. parapsilosis complex. CONCLUSION: This is the first report of the emergence and molecular mechanisms of fluconazole resistance in C. parapsilosis species complex from Pakistan. Y132F mutation in the ERG11 gene was the most common mutation in fluconazole-resistant strains. These findings are concerning and necessitate better diagnostics, newer antifungals, ongoing surveillance and further insights on resistance mechanisms in the country.

Analysis of fks1 and fks2 gene mutations in invasive Candida glabrata strains from Pakistan.

INTRODUCTION: The gradual increase in caspofungin usage in Pakistan raises a concern of emergence of echinocandin resistance in local Candida glabrata strains. We sequenced and determined mutations in fks1 and fks2 genes in invasive Candida glabrata strains from Pakistan. MATERIAL AND METHODS: Thirty-six invasive C. glabrata strains were selected with median (min-max) minimum inhibitory concentrations (MICs) of 0.06 (0.015-0.25) mg/L for caspofungin, 0.015 (0.008-0.06) mg/L for micafungin and 0.06 (0.015-0.12) mg/L for anidulafungin. fks1 and fks2 gene fragments were sequenced using Sanger methodology. Sequences were analysed with MEGA-6 software to identify specific single-nucleotide polymorphisms (SNP) against wild-type sequences of C. glabrata. RESULTS: In fks1 gene, non-synonymous mutation D632H was observed in one isolate with caspofungin MIC of 0.25 mg/L. Synonymous mutation at position A742 was observed in 26/36 (72%) of the isolates. 34/36 (94.5%) isolates analysed for fks2 gene were observed as wild type. A novel non-synonymous mutation at I661T was observed in fks2 gene in one isolate with caspofungin MIC of 0.12 mg/L and anidulafungin and micafungin MIC of 0.06 and 0.015 mg/L, respectively. Novel fks2 synonymous mutations at position T647, K652 and I706 were observed in 16/36 (44%), 25/36 (69%) and 23/36 (63%) isolates, respectively. CONCLUSION: Low frequencies of both non-synonymous and synonymous polymorphisms were observed in invasive C. glabrata strains. Since S663P in fks2 gene is associated with caspofungin resistance, a novel mutation at 661 codon identified in our study needs correlation with treatment outcome data and mandates periodic genomic surveillance.

Comparison of risk factors and outcome of patients with and without COVID-19-associated pulmonary aspergillosis from Pakistan: A case-control study.

BACKGROUND: Early identification of COVID-19-associated pulmonary aspergillosis (CAPA) is particularly challenging in low- middle-income countries where diagnostic capabilities are limited, and risk factors for CAPA have not been identified. It is also essential to recognise CAPA patients who are likely to have a poorer outcome to decide on aggressive management approaches. Therefore, this study aimed to identify risk factors and outcomes for CAPA among admitted moderate to critical COVID-19 patients at our centre in Pakistan. METHODS: An unmatched case-control study with ratio of 1:2 was conducted on hospitalised adult patients with COVID-19 from March 2020-July 2021. Cases were defined according to European Confederation of Medical Mycology and the International Society for Human and Animal Mycology consensus criteria. Controls were defined as patients hospitalised with moderate, severe or critical COVID-19 without CAPA. RESULTS: A total of 100 CAPA cases (27 probable CAPA; 73 possible CAPA) were compared with 237 controls. Critical disease at presentation (aOR 5.04; 95% CI 2.18-11.63), age ≥ 60 years (aOR 2.00; 95% CI 1.20-3.35) and underlying co-morbid of chronic kidney disease (CKD) (aOR 3.78; 95% CI 1.57-9.08) were identified as risk factors for CAPA. Patients with CAPA had a significantly greater proportion of complications and longer length of hospital stay (p-value < .001). Mortality was higher in patients with CAPA (48%) as compared to those without CAPA (13.5%) [OR = 6.36(95% CI 3.6-11)]. CONCLUSIONS: CAPA was significantly associated with advanced age, CKD and critical illness at presentation, along with a greater frequency of complications and higher mortality.

Diagnostic accuracy of different cut-off values of adenosine deaminase levels in tuberculous pleural effusion.

Objectives: To assess the diagnostic accuracy of different cut-off values of pleural fluid adenosine deaminase levels as a diagnostic method for tuberculous pleural effusion. METHODS: The prospective study was conducted from 2014 to 2016 at the Aga Khan University Hospital, Karachi, and comprised pleural fluid samples of adult patients with and without tuberculosis which were tested for adenosine deaminase levels, and divided into tuberculosis group A and non-tuberculosis group B. Sensitivity, specificity, negative predictive value and positive predictive value were calculated using different cut-offs. Data was analysed using IBM SPSS (Statistical Package for Social Sciences) version 21.0 (IBM Corp., Armonk, NY). RESULTS: Of 155 patients, 46(29.7%) had tuberculosis; 30(65.2%) males and 16(34.8%) females. Those who did not have tuberculosis were 109(70.3%); 69(63.3%) males and 40(36.7%) females. The adenosine deaminase levels were elevated in group A compared to group B (p<0.001). The cut-off of 30U/L showed the highest sensitivity (71.7%) and negative predictive value (87.4%), and a specificity of 82.6%. The cut-off of 50U/L showed the highest specificity (89.9%) with sensitivity 52.2%, and the cut-off of 40U/L showed the highest positive predictive value of 68.9% with sensitivity 67.4% and specificity 87.2%. CONCLUSIONS: Pleural fluid adenosine deaminase testing for diagnosing tuberculosis pleuritis revealed highest sensitivity and moderate specificity for cut-off value of 30U/L.

Fungal isolation from wound samples submitted for culture at a tertiary care hospital laboratory.

Fungal wound infections are increasing worldwide. The aim of this retrospective study, conducted at the Aga Khan University laboratory, Karachi, Pakistan, was to determine the frequency of fungal isolation in wound specimens. Data of wound samples received for culture from all over the country between September and October 2018 was reviewed. Samples were processed for bacterial cultures and additionally inoculated on Sabouraud's dextrose medium. Demographic information, medical history and information on the type of wound was collected. A total of 140 cases were included, of which 87 (81%) were culture positive, while 10 (7%) cases yielded fungi. Burn and blast wounds had the highest proportion of fungal isolation, i.e. 2 out of 4 (50%). Candida species were the most common fungi (n=4), followed by Fusarium species (n=3). This study reports an alarming rate of fungal wound infections. As fungal necrotising wound infections have high morbidity and mortality, it is, therefore, important to accurately diagnose and treat such infections in local setting.

Extraintestinal Seeding of Salmonella enterica Serotype Typhi, Pakistan.

We evaluated Salmonella enterica serotype Typhi strains isolated from all body sites in Pakistan during 2013-2018. Despite an increase in overall number of localized, extensively drug-resistant Salmonella Typhi in organ infections during 2018, there was no increase in the proportion of such isolates in comparison with non-extensively drug-resistant isolates.

C. auris and non-C. auris candidemia in hospitalized adult and pediatric COVID-19 patients; single center data from Pakistan.

We compared candidemia due to Candida auris and other non-C.auris cases in hospitalized COVID-19 patients over a period of 9 months at our institution. Candidemia cases in all admitted patients (with or without COVID-19) from April to December 2020 were identified. Electronic records were accessed to record clinical data of COVID-19 patients with candidemia. For statistical analysis, independent samples Mann-Whitney U test was used for continuous and Fisher's exact test was used for categorical variables.A total of 26 candidemia cases (four C.auris, 22 non-C.auris) in 2438 admitted COVID-19 (10.7 per 1000 admissions) and 59 candidemia cases (six C.auris, 53 non-C.auris) in admitted non-COVID patients (8.2 per 1000 admission) were identified. The proportion of C.auris candidemia in COVID-19 and non-COVID-19 patients was 15.4 and 10%, respectively. 4/26 of COVID-19 candidemia patients were aged ≤ 15 years (10 months--15 years). Comparison of C.auris and non-C. auris candidemia cases reveal significant difference in prior antifungal exposure, present in 100% C. auris candidemia versus 27% non-C. auris candidemia patients (P-value 0.014). Although not statistically significant, C. auris candidemia patients had a longer stay in hospital before candidemia (20 vs. 9 days), higher isolation rate of multidrug resistant bacteria (100 vs. 50%), increased rate of prior colonization of Candida species (50 vs. 14%) and lower mean beta-d-glucan levels (48.73 pg/ml vs. 138.146 pg/ml). Both C. auris and non-C. auris COVID-19 patients had similar mortality rate (67 vs. 65%). A significant number of critically ill COVID-19 patients developed candidemia in our study highlighting the need for prompt diagnosis and management. LAY SUMMARY: 26 candidemia cases (4 Candida auris;22 non-C. auris) in COVID-19 patients (April-December 2020) are reported from Pakistan. Compared to non-C. auris, C. auris candidemia patients had higher prior antifungal exposure, longer hospital stay, higher rates of MDR bacteria and Candida colonization.

Antimicrobial resistance among GLASS priority pathogens from Pakistan: 2006-2018.

BACKGROUND: In 2018 Pakistan initiated its national antimicrobial resistance (AMR) surveillance aligned with Global Antimicrobial Surveillance System (GLASS). To complement this surveillance, we conducted a situational analysis of AMR rates among GLASS organisms in the country. Data from published studies and from antibiograms was compared and role of antibiograms as potential contributors to national AMR surveillance explored. METHODS: AMR rates for GLASS specified pathogen/antimicrobials combination from Pakistan were reviewed. Data sources included published studies (2006-2018) providing AMR rates from Pakistan (n = 54) as well as antibiograms (2011-2018) available on the Pakistan Antimicrobial Resistance Network (PARN) website. Resistance rates were categorized as follows: Very low: 0-10%, Low: 11-30%, Moderate: 30-50% and High: > 50%. RESULTS: Published data from hospital and community/laboratory-based studies report resistance rates of > 50% and 30-50% respectively to 3rd generation cephalosporins, fluoroquinolones and cotrimoxazole amongst Klebsiella pneumoniae and Escherichia coli. Carbapenem resistance rates amongst these organisms remained below 30%. High (> 50%) resistance was reported in Acinetobacter species to aminoglycosides and carbapenems among hospitalized patients. The evolution of ceftriaxone resistant Salmonella Typhi and Shigella species is reported. The data showed > 50% to fluoroquinolones amongst Neisseria gonorrhoeae and the spread of methicillin resistant Staphylococcus aureus (< 30%; 2008) to (> 50%; 2010) in hospital settings. Resistance reported in published studies aligned well with antibiogram data. The latter also captured a clear picture of evolution of resistance over the study period. CONCLUSION: Both published studies as well antibiograms suggest high rates of AMR in Pakistan. Antibiogram data demonstrating steady increase in AMR highlight its potential role towards supplementing national AMR surveillance efforts particularly in settings where reach of national surveillance may be limited.

Respiratory pathogens in patients with acute exacerbation of non-cystic fibrosis bronchiectasis from a developing country.

Bronchiectasis unrelated to cystic fibrosis (non-CF bronchiectasis) has become a major respiratory disease in developing nations. The dilated mucus filled airways promote bacterial overgrowth followed by chronic infection, bronchial inflammation, lung injury and re-infection. Accurate pathogen identification and antimicrobial susceptibility allowing appropriate treatment, in turn, may break this vicious cycle.  This study aimed to gain kowledge about the spectrum and antimicrobial spectrum of pathogen yielded from respiratory specimens in adult patients with acute exacerbation of non-cystic fibrosis (CF) bronchiectasis. This cross-sectional study was performed at the pulmonology clinics of the Aga Khan University, Karachi, Pakistan from 2016-2019. Respiratory specimens were collected from adult patients with acute exacerbation of non-CF bronchiectasis presenting in pulmonology clinics. Microbial cultures were performed using standard methodology. Susceptibility testing was performed and interpreted using Clinical Laboratory Standard Institute criteria.  A total of 345 positive cultures from 160 patients presenting with acute exacerbation were evaluated. The most frequent organisms were Pseudomonas aeruginosa (n=209) followed by Hemophilus influenzae (n=40) and Staphylococcus aureus (n=24). High rates of antimicrobial resistance were found in all these pathogens. Proportion of Pseudomonas aeruginosa strains resistant to ciprofloxacin, imipenem, ceftazidime and piperacillin-tazobactam were 27.1%, 16.8%, 14.8% and 13.1% respectively. 65% of Hemophilus influenzae strains were resistant to cotrimoxazole and ciprofloxacin and 66.7% of Staphylococcus aureus strains were resistant to methicillin. High antimicrobial resistance in non-CF bronchiectasis patients against commonly used antimicrobials is a concern and highlight need for urgent community level interventions to improve clinical outcome in these patients.

Chikungunya outbreak in Karachi Pakistan 2016-2017: An analysis of viral isolates.

In December 2016 physicians in Karachi, Pakistan,witnessed an increase in patients presenting with febrile illness and severe polyarthralgia. Subsequently, chikungunya virus (CHIKV)) was isolated from three patients. This virus was sequenced and compared with other isolates of CHIKV obtained in India and Pakistan during recent outbreaks. Phylogenetic analysis indicated that the Karachi isolates were most similar to the East Central South African CHIKV lineage and showed sequence homology to isolates obtained in other parts of Pakistan and India. More importantly, two of the CHIKV isolates had a nucleotide substitution in the E1 gene corresponding to an amino acid change at chain F portion of the E1 protein.

Persistence of Candida auris on latex and nitrile gloves with transmission to sterile urinary catheters‡.

Candida auris' ability to persist on contaminated gloves and transmit to urinary catheters was evaluated. 105 and 103 cfu/ml suspensions of eight Candida species including C. auris were inoculated on latex and nitrile gloves fingertips and touched on agar surface at different time intervals. Urinary catheter piece, touched by latex glove carrying Candida spp. suspensions at various time intervals, was cultured by roll-plate method. C.auris persisted on latex gloves at both 105 and 103 cfu/ml up to 3 minutes and could be transmitted from both wet and dry contaminated gloves to catheters. Proper glove use with strict hand hygiene should be advocated in settings with ongoing C.auris transmission.

Comparison of risk factors and outcomes of Candida auris candidemia with non-Candida auris candidemia: A retrospective study from Pakistan.

Candida auris has emerged as a nosocomial multi-drug resistant pathogen. This study aimed to compare the risk factors and outcomes of C. auris candidemia patients with non-C. auris candidemia, at a single center in Pakistan. A retrospective study compared 38 C. auris with 101 non-C. auris (36 C. albicans, 38 C. tropicalis, and 27 C. parapsilosis) candidemia patients between September 2014 and March 2017 at the Aga Khan University Hospital, Pakistan. Demographics, clinical history, management and outcomes were studied. Prior history of surgery (adjusted odds ratio [aOR] 4.9, 95% confidence interval [CI]: 1.4-17.5), antifungals exposure (aOR 38.3, 95% CI: 4.1-356) and prior MDR bacteria isolation (aOR 5.09, 95% CI: 1.6-15.9) were associated with C. auris candidemia. On survival analysis both groups of patients had similar outcome in terms of mortality (62.6% vs. 52.54%, hazard ratio [HR] 1.45, 95% CI: 0.84-2.4, P-value = .17) and microbiological failure rates (42.3% vs. 32.2%, HR 0.65, 95% CI: 0.35-1.2, P-value = .17) however, C. auris patients had a higher mean hospital stay (36.32 days vs. 14.8 days, P-value = <.001) and higher >15-day in-hospital stay from positive culture (HR 2.68, 95% CI: 1.1-6.3, P-value = .025). Antifungal susceptibility was different, with C. auris more often resistant to voriconazole (29.6% vs. 0%) and amphotericin (3.7 vs. 0%); though no echinocandin resistance was detected in either group. As opposed to other Candida species, C. auris candidemia occurred after nosocomial exposure, and its source was most commonly an indwelling line. Although these patients had a higher in-hospital stay, but there was no excess mortality when compared to other Candida species.

COVID-19-associated pulmonary aspergillosis (CAPA) in patients admitted with severe COVID-19 pneumonia: An observational study from Pakistan.

BACKGROUND: Invasive aspergillosis is a well-known complication of severe influenza pneumonia with acute respiratory distress syndrome (ARDS). However, recent studies are reporting emergence of aspergillosis in severe COVID-19 pneumonia, named as COVID-19-associated pulmonary aspergillosis (CAPA). METHODS: A retrospective observational study was conducted in patients with severe COVID-19 pneumonia from February 2020 to April 2020. Patients ≥18 years of age with clinical features and abnormal chest imaging with confirmed COVID-19 by RT-PCR for SARS-CoV-2 were included. CAPA was diagnosed based on clinical parameters, radiological findings and mycological data. Data were recorded on a structured proforma, and descriptive analysis was performed using Stata ver 12.1. RESULTS: A total of 147 patients with confirmed COVID-19 and 23 (15.6%) patients requiring ICU admission were identified. Aspergillus species were isolated from tracheal aspirates of nine (39.1%) patients, and of these, five patients (21.7%) were diagnosed with CAPA and four (17.4%) had Aspergillus colonisation. The mean age of patients with CAPA was 69 years (Median age: 71, IQR: 24, Range: 51-85), and 3/5 patients were male. The most frequent co-morbid was diabetes mellitus (4/5). The overall fatality rate of COVID-19 patients with aspergillosis was 44% (4/9). The cause of death was ARDS in all three patients with CAPA, and the median length of stay was 16 days (IQR: 10; Range 6-35 days). CONCLUSION: This study highlights the need for comparative studies to establish whether there is an association of aspergillosis and COVID-19 and the need for screening for fungal infections in severe COVID-19 patients with certain risk factors.

Evaluation of semi-quantitative compared to quantitative cultures of tracheal aspirates for the yield of culturable respiratory pathogens - a cross-sectional study.

BACKGROUND: Diagnosis of lower respiratory tract infections (LRTI) depends on the presence of clinical, radiological and microbiological findings. Endotracheal suction aspirate (ETSA) is the commonest respiratory sample sent for culture from intubated patients. Very few studies have compared quantitative and semi-quantitative processing of ETSA cultures for LRTI diagnosis. We determined the diagnostic accuracy of quantitative and semi-quantitative ETSA culture for LRTI diagnosis, agreement between the quantitative and semi quantitative culture techniques and the yield of respiratory pathogens with both methods. METHODS: This was a cross-sectional study conducted at the Aga Khan University clinical laboratory, Karachi, Pakistan. One hundred and seventy-eight ETSA samples sent for routine bacteriological cultures were processed quantitatively as part of regular specimen processing method and semi-quantitatively. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and diagnostic accuracy was calculated for both methods using clinical diagnosis of pneumonia as reference standard. Agreement between the quantitative and semi quantitative methods was assessed via the kappa statistic test. Pathogen yield between the two methods was compared using Pearson's chi-square test. RESULTS: The quantitative and semi-quantitative methods yielded pathogens in 81 (45.5%) and 85 (47.8%) cases respectively. There was complete concordance of both techniques in 155 (87.1%) ETSA samples. No growth was observed in 45 (25.3%) ETSA specimens with quantitative culture and 37 (20.8%) cases by semi-quantitative culture. The diagnostic accuracy of both techniques were comparable; 64.6% for quantitative and 64.0% for semi-quantitative culture. The kappa agreement was found to be 0.84 (95% CI, 0.77-0.91) representing almost perfect agreement between the two methods. Although semi-quantitative cultures yielded more pathogens (47.8%) as compared to quantitative ETSA cultures (45.5%), the difference was only 2.3%. However, this difference achieved statistical (chi-square p-value < 0.001) favoring semi-quantitative culture methods over quantitative culture techniques for processing ETSA. CONCLUSION: In conclusion, there is a strong agreement between the performances of both methods of processing ETSA cultures in terms of accuracy of LRTI diagnosis. Semi-quantitative cultures of ETSA yielded more pathogens as compared to quantitative cultures. Although both techniques were comparable, we recommend processing of ETSA using semi-quantitative technique due to its ease and reduced processing time.

Efforts to improve diagnosis of bacteraemia by reducing blood culture contamination in an emergency department: strategies and outcome.

OBJECTIVE: To assess the strategies and outcome for reducing blood culture contamination in order to improve the diagnosis of bacteraemia. METHODS: The interventional study was conducted at a tertiary care hospital in Karachi from January 1, 2013, to December 31, 2016. The blood culture contamination data related to the first year of the study was taken as the baseline pre-intervention data. Strategies were planned as intervention for improvement by consolidating training and education in the form of dedicated lectures, practising on mannequins and developing in-house video, replacing povidone with 2% chlorhexidine preparation spray plus 70% isopropyl alcohol swabs and inducting dedicated phlebotomy team whose only responsibility was blood sample collection and minimising the probability of error. RESULTS: In 2013, there were 8868 samples; 7402 in 2014; 6897 in 2015; and 9756 samples in 2016. The contamination rate in 2013 was 8% which went down to 7.75% in 2014, 4.25% in 2015 and 3.9% in 2016. The decline became statistically significant (p<0.001) after implementing a dedicated phlebotomy team in the emergency department. CONCLUSIONS: Apart from teaching and training, the concept of blood culture collection kit with checklist and dedicated blood collection team was found to be vital in reducing blood culture contamination.

Clinical spectrum and factors impacting outcome of Candida auris: a single center study from Pakistan.

BACKGROUND: An outbreak of Candida auris began globally in 2014 including Pakistan and since then it has emerged as a nosocomial multi-drug resistant pathogen. The aim of this study was to assess the clinical spectrum and outcome of patients, from a single center in Pakistan, in whom C. auris was isolated. METHODS: A retrospective study was conducted on 92 patients; ≥16 years with at least one culture positive for C. auris, at the Aga Khan University Hospital Karachi, Pakistan from Sept 2014-Mar 2017.Demographics, clinical history, management and outcome were studied. A logistic regression model was used to identify the risk factors for mortality. RESULTS: We identified 92 patients with C. auris (193 isolates), of whom 52.2% were males. Mean age was 54.14 ± 20.4 years. Positive cultures were obtained after a median hospital stay of 14 days. Most patients had a history of surgery (57.6%), antibiotic use (95.6%), ICU stay (44.6%), indwelling lines (88.04%) and isolation of another multi-resistant organism (52.2%).Most patients were symptomatic (70.7%). Amongst these, 38 had candidemia while 27 had non-candidemia infections. Sites of infection included central lines (35), urinary tract (19), peritonitis (4), nosocomial ventriculitis (1), empyema (1), fungal keratitis (1) otitis externa (1) and surgical site (1). Fluconazole resistance was 100% while 28.5 and 7.9% were Voriconazole and Amphotericin resistant respectively. Overall crude mortality was 42.4% while 14-day mortality was 31.5%. Both infected and colonized cases shared similar mortality (46.2% vs 33.3%; p-value = 0.25). Among infected cases mortality was high in candidemia compared to non-candidemia (60.5% vs 25.9%) in which deaths related to C. auris were 34.2% vs 22.2% respectively. On multivariate analysis candidemia (AOR 4.2, 95% CI: 1.09-16.49; p-value = 0.037) was associated with greater mortality with source control being the only protective factor for mortality (AOR 0.22, 95% CI: 0.05-0.92; p-value0.038] while ICU stay, rapidity of blood culture clearance, DM, malignancy and MDR co-infection had no impact. CONCLUSION: Patients with C.auris from a single center in Pakistan have a wide clinical spectrum with line associated infection being the predominant site of infection. Candidemia leads to high mortality while source control improves outcome.

Antimicrobial sensitivity pattern, demographic findings and risk factors amongst meningitis and non-meningitis invasive Streptococcus pneumoniae at Aga Khan University Hospital Clinical Laboratory, Karachi, Pakistan.

OBJECTIVE: To determine the resistance rate of penicillin and ceftriaxone amongst invasive meningitis and nonmeningitis isolates of streptococcus pneumoniae. METHODS: The prospective cross-sectional study was conducted from January 2011 to March 2014 at the Clinical Microbiology Laboratory of Aga Khan University, Karachi, and comprised all invasive strains of streptococcus pneumoniae. Penicillin and ceftriaxone susceptibilities were performed and interpreted based on minimum inhibitory concentration breakpoints recommended by Clinical and Laboratory Standards Institute guidelines. Data was analysed using Stata 12. RESULTS: There were 163 strains isolated from sterile body fluids of 109 patients. Of the total, 46(28%) samples were meningitic while 117(72%) were non-meningitic. Of the meningeal isolates, 12(26%) were resistant to penicillin, while none was resistant to ceftriaxone and vancomycin. None of non meningeal isolates showed resistance to penicillin, ceftriaxone or vancomycin. CONCLUSION: There was considerable penicillin resistance among meningeal strains of streptococcus pneumoniae, but here appeared to be no need to add vancomycin for empirical treatment of invasive streptococcus pneumonia infection.

Simultaneous Emergence of Multidrug-Resistant Candida auris on 3 Continents Confirmed by Whole-Genome Sequencing and Epidemiological Analyses.

BACKGROUND: Candida auris, a multidrug-resistant yeast that causes invasive infections, was first described in 2009 in Japan and has since been reported from several countries. METHODS: To understand the global emergence and epidemiology of C. auris, we obtained isolates from 54 patients with C. auris infection from Pakistan, India, South Africa, and Venezuela during 2012-2015 and the type specimen from Japan. Patient information was available for 41 of the isolates. We conducted antifungal susceptibility testing and whole-genome sequencing (WGS). RESULTS: Available clinical information revealed that 41% of patients had diabetes mellitus, 51% had undergone recent surgery, 73% had a central venous catheter, and 41% were receiving systemic antifungal therapy when C. auris was isolated. The median time from admission to infection was 19 days (interquartile range, 9-36 days), 61% of patients had bloodstream infection, and 59% died. Using stringent break points, 93% of isolates were resistant to fluconazole, 35% to amphotericin B, and 7% to echinocandins; 41% were resistant to 2 antifungal classes and 4% were resistant to 3 classes. WGS demonstrated that isolates were grouped into unique clades by geographic region. Clades were separated by thousands of single-nucleotide polymorphisms, but within each clade isolates were clonal. Different mutations in ERG11 were associated with azole resistance in each geographic clade. CONCLUSIONS: C. auris is an emerging healthcare-associated pathogen associated with high mortality. Treatment options are limited, due to antifungal resistance. WGS analysis suggests nearly simultaneous, and recent, independent emergence of different clonal populations on 3 continents. Risk factors and transmission mechanisms need to be elucidated to guide control measures.

Agreement of Direct Antifungal Susceptibility Testing from Positive Blood Culture Bottles with the Conventional Method for Candida Species.

Early availability of antifungal susceptibilities can ensure timely institution of targeted therapy in candidemia, which can improve patient outcomes. This study prospectively determines the agreement between the results of direct testing of antifungal susceptibilities from blood culture bottles by disk diffusion and Etest and the results of standardized susceptibility testing methods; direct testing would allow susceptibility results to be available 1 to 2 days earlier. A total of 104 blood cultures with different Candida species (28% C. albicans, 27% C. parapsilosis, 26% C. tropicalis, etc.) were evaluated between January 2012 and May 2013 for agreement of fluconazole, voriconazole, and amphotericin B susceptibility results by disk diffusion. Agreement in MICs obtained by Etest was determined for fluconazole (21 isolates), voriconazole (28 isolates), amphotericin (29 isolates), and caspofungin (29 isolates). The kappa scores for categorical agreement were highest for fluconazole by disk diffusion (0.902, standard error [SE] = 0.076) and Etest (1.00, SE = 0.218) and for amphotericin B by disk diffusion (1.00, SE = 0.098). The Pearson correlation (r) of zone diameters was strongest for fluconazole (0.69) and amphotericin (0.70) and moderate for voriconazole (0.60), and the Pearson correlation of MICs was strongest for fluconazole (0.94) and caspofungin (0.88). However, the moderate correlation of amphotericin MICs with zone diameters (-0.42) precludes the use of amphotericin B disk diffusion for susceptibility testing. There were no very major errors; however, there were 1 (1%) major and 5 (4.8%) minor errors with disk diffusion and 4 (13.3%) minor errors with Etest. Thus, antifungal disk diffusion directly from blood culture bottles is a rapid and easy method for fluconazole and voriconazole susceptibility testing for timely tailoring of candidemia therapy.

Antimicrobial susceptibility testing of Neisseria gonorrhoeae isolates in Pakistan by Etest compared to Calibrated Dichotomous Sensitivity and Clinical Laboratory Standards Institute disc diffusion techniques.

BACKGROUND: Accurate detection of Neisseria gonorrhoeae antimicrobial resistance is essential for appropriate management and prevention of spread of infection in the community. In this study Calibrated Dichotomous Sensitivity (CDS) and Clinical Laboratory Standards Institute (CLSI) disc diffusion methods were compared with minimum inhibitory concentration (MIC) by Etest in Neisseria gonorrhoeae isolates from Karachi, Pakistan. CDS and CLSI disc diffusion techniques, and Etest for ceftriaxone, penicillin G, spectinomycin and ciprofloxacin against 100 isolates from years 2012-2014 were performed. Due to lack of CLSI breakpoints for azithromycin, it was interpreted using cut-offs from British Society of Antimicrobial Chemotherapy (BSAC). Due to lack of low concentration tetracycline discs, tetracycline was tested with CLSI disc diffusion and Etest only. Comparisons were based on the identified susceptibility, intermediate susceptibility and resistance (SIR) categories using the different methods. Complete percent agreement was percentage agreement achieved when test and reference method had identical SIR-category. Essential percent agreement was percentage agreement when minor discrepancies were disregarded. RESULTS: There was 100 % and 99 % overall essential agreement and 50 % versus 23 % overall complete agreement by CDS and CLSI methods, respectively, with MICs for all tested antibiotics. Using either method, there was 100 % complete agreement for ceftriaxone and spectinomycin. There was 90 % versus 86 % complete agreement for ciprofloxacin, and 60 % and 75 % for penicillin using CDS and CLSI method, respectively. Essential agreement of 99 % and complete agreement of 62 % was found for tetracycline with CLSI method. There was 100 % essential and complete agreement by CDS, BSAC and Etest for azithromycin. CONCLUSION: No major errors with regard to identified SIR-categories were found for penicillin, ciprofloxacin, ceftriaxone and spectinomycin using CLSI and CDS methods. All isolates were susceptible to ceftriaxone and spectinomycin, and 99 % to azithromycin. In low-resource settings, both the CLSI and CDS disc diffusion techniques might be used for susceptibility testing of gonococcal isolates. However, these methods require considerable standardization and quality controls for adequate levels of reproducibility and correct interpretation to reflect appropriately the MIC values of the different antimicrobials. New, emerging, or rare resistance should be confirmed by MIC determination.