scholarly journals Corneal Culture in Infectious Keratitis: Effect of the Inoculation Method and Media on the Corneal Culture Outcome

2021 ◽  
Vol 10 (9) ◽  
pp. 1810
Author(s):  
Susanna Sagerfors ◽  
Chrysoula Karakoida ◽  
Martin Sundqvist ◽  
Birgitta Ejdervik Lindblad ◽  
Bo Söderquist

Background: To compare two different methods of corneal culture in infectious keratitis: multiple sampling for direct inoculation and enrichment (standard method) and a single sample via transport medium for indirect inoculation (indirect inoculation method). Methods: Prospective inclusion of patients fulfilling predefined criteria of infectious keratitis undergoing corneal culture according to both studied methods in a randomized order. Results: The standard method resulted in a significantly higher proportion of positive culture outcomes among the 94 included episodes of infectious keratitis (61%; 57/94) than the indirect inoculation method (44%; 41/94) (p = 0.002) and a significantly higher proportion of microorganisms than the indirect inoculation method, with a Cohen’s kappa of 0.38 (95% CI: 0.28–0.49) for agreement between the methods. Subanalysis of culture results showed that direct inoculation on gonococcal agar only combined with the indirect inoculation method resulted in a similar rate of culture positive patients and proportion of detected microorganisms to the standard method. Conclusion: Indirect inoculation of one corneal sample cannot replace direct inoculation of multiple corneal samples without loss of information. A combination of directly and indirectly inoculated samples can reduce the number of corneal samples by four without statistically significant differences in culture outcome or in the proportion of detected microorganisms.

2020 ◽  
Vol 5 (1) ◽  
pp. e000363
Author(s):  
Susanna Sagerfors ◽  
Birgitta Ejdervik-Lindblad ◽  
Bo Söderquist

ObjectiveThis study aimed to compare the efficacy of a cotton tipped applicator and a knife blade in obtaining corneal samples in patients with infectious keratitis.Methods and analysisThis is a retrospective cohort study of patients with suspected infectious keratitis during 2004–2014. Samples for corneal culture were obtained by a cotton tipped applicator and a knife blade, and directly inoculated on GC agar, blood agar and Sabouraud agar.ResultsIn all, 355 patients were included. Corneal sampling by cotton tipped applicator yielded a significantly higher rate of patients with positive corneal culture, 156/355 (43.9%), compared with knife blade, 111/355 (31.3%) (p<0.001). On a patient level, the culture results obtained by the cotton tipped applicator and the knife blade were identical in 269/355 (76%) of the patients. The overall agreement between the two instruments on microbial level was 0.66 (Cohen’s kappa 95% CI 0.60 to 0.72).ConclusionCorneal sampling by cotton tipped applicator generated a higher rate of positive corneal cultures and a higher proportion of isolated microbes than by knife blade. Future studies with randomised sampling order are needed to establish which instrument, cotton tipped applicator or knife blade, is the most effective in sampling microbes for direct inoculation in patients with infectious keratitis.


2020 ◽  
Vol 7 (10) ◽  
Author(s):  
Marcos C Schechter ◽  
Mohammed K Ali ◽  
Benjamin B Risk ◽  
Adam D Singer ◽  
Gabriel Santamarina ◽  
...  

Abstract Background Diabetes is the leading cause of lower extremity nontraumatic amputation globally, and diabetic foot osteomyelitis (DFO) is usually the terminal event before limb loss. Although guidelines recommend percutaneous bone biopsy (PBB) for microbiological diagnosis of DFO in several common scenarios, it is unclear how frequently PBBs yield positive cultures and whether they cause harm or improve outcomes. Methods We searched the PubMed, EMBASE, and Cochrane Trials databases for articles in any language published up to December 31, 2019, reporting the frequency of culture-positive PBBs. We calculated the pooled proportion of culture-positive PBBs using a random-effects meta-analysis model and reported on PBB-related adverse events, DFO outcomes, and antibiotic adjustment based on PBB culture results where available. Results Among 861 articles, 11 studies met inclusion criteria and included 780 patients with 837 PBBs. Mean age ranged between 56.6 and 71.0 years old. The proportion of males ranged from 62% to 86%. All studies were longitudinal observational cohorts, and 10 were from Europe. The range of culture-positive PBBs was 56%–99%, and the pooled proportion of PBBs with a positive culture was 84% (95% confidence interval, 73%–91%). There was heterogeneity between studies and no consistency in definitions used to define adverse events. Impact of PBB on DFO outcomes or antibiotic management were seldom reported. Conclusions This meta-analysis suggests PBBs have a high yield of culture-positive results. However, this is an understudied topic, especially in low- and middle-income countries, and the current literature provides very limited data regarding procedure safety and impact on clinical outcomes or antibiotic management.


1999 ◽  
Vol 37 (11) ◽  
pp. 3583-3585 ◽  
Author(s):  
C. C. Olsen ◽  
J. R. Schwebke ◽  
W. H. Benjamin ◽  
A. Beverly ◽  
K. B. Waites

Two commercial swab transport systems, Copan Amies gel agar with and without charcoal (Copan Diagnostics, Corona, Calif.), were compared to direct inoculation onto modified Thayer-Martin medium for detection of Neisseria gonorrhoeae in 1,490 endocervical specimens obtained from women attending a sexually transmitted disease clinic. Copan swabs were held in the transport system for 24 h at room temperature prior to inoculation onto modified Thayer-Martin medium. All cultures were incubated at 35°C in 5% CO2, and bacteria were identified on the basis of Gram stain, oxidase, and biochemical reactions. Copan Amies gel agar transport system without charcoal detected 77 of 81 (95%) direct inoculation culture-positive specimens, and Copan Amies gel agar transport system with charcoal detected 53 of 56 (95%) directly inoculated culture-positive specimens. Copan Amies gel agar without charcoal inoculated after 6 h supported growth of 56 (98%) positive cultures out of only 55 directly inoculated culture-positive specimens. This study demonstrates that Copan swabs represent a reasonable alternative, providing convenience, low cost, and ease of use while still maintaining a satisfactory recovery rate of N. gonorrhoeae from clinical specimens, if specimens can be inoculated onto selective media within a relatively short time period not involving overnight shipment.


2018 ◽  
Vol 38 (1) ◽  
pp. 65-67
Author(s):  
Louis L. Huang ◽  
Ellen Ramas ◽  
Priti Prasad ◽  
Jenny Catania ◽  
Pauline Meade ◽  
...  

There is a paucity of data on the sterility of peritoneal dialysis fluid (PDF) after drug admixture. International Society for Peritoneal Dialysis (ISPD) guidelines suggest using sterile technique when admixing antibiotics; however, the degree of sterility remains unclear. This issue is most pertinent when preparing take-home PDF for outpatient treatment of peritonitis. This study compares the sterility of PDF admixed with antibiotics using a non-touch aseptic technique (NTAT) versus sterile technique. Groups of 8 PDF mixtures (1.5% Dianeal or Icodextrin [Baxter International Inc., Spring Grove, IL, USA]) were admixed with 1 g/L ceftazidime and vancomycin, or 20 mL saline, either by a pharmacist using sterile technique in a sterile suite, or a nurse in a clinical room using NTAT. Dianeal inoculated with 1 x 106 colony-forming units (CFU)/L of coagulase-negative Staphylococcus (CNS), with and without antibiotics, served as positive controls. Admixed PDFs were left at room temperature for 72 hours, then cultured using the BacT/ALERT system. A positive culture by day 5 constituted a contamination. Differences in proportion of contamination between groups were assessed using the Chi-squared test. Eighty PDF bags underwent microbiological testing. Sterility was maintained in all bags, independent of technique (NTAT versus sterile technique), type of PDF (Dianeal versus Icodextrin), or whether antibiotics were admixed. Of the positive controls, CNS-inoculated PDFs without antibiotics were all culture positive; however, when inoculated into antibiotic-admixed PDFs, only S. haemolyticus remained culture-positive ( p < 0.0001). In conclusion, PDF sterility can be maintained using NTAT for up to 3 days at room temperature. Currently, there is insufficient evidence to adopt sterile technique in sterile suites when admixing take-home PDF.


2020 ◽  
Vol 71 (Supplement_2) ◽  
pp. S130-S140
Author(s):  
William L Still ◽  
Milagritos D Tapia ◽  
Sharon M Tennant ◽  
Mamadou Sylla ◽  
Aliou Touré ◽  
...  

Abstract Background Salmonella enterica bloodstream infections are an important cause of childhood morbidity and mortality, including in Mali. We report 17 years of surveillance for nontyphoidal and typhoidal S. enterica infections among inpatients and outpatients at l’Hôpital Gabriel Touré, the main source of pediatric tertiary care in Bamako, Mali. Methods Between June 2002 and December 2018, a blood culture was collected from 54 748 children aged ≤15 years with fever and/or suspected invasive bacterial infection who provided consent (38 152 inpatients, 16 596 outpatients). Bacterial pathogens were identified using standard microbiological techniques and serovars of S. enterica were determined by PCR and/or agglutination with antisera. Results Nontyphoidal Salmonella (NTS) was identified in 671 enrolled inpatients (1.8% of all enrolled inpatients, 13.8% of enrolled inpatients with a positive culture). S. Enteritidis, the most common NTS serovar, accounted for 38.5% of all NTS isolates (n = 258), followed by S. Typhimurium (31.7%, n = 213). The median (SD) age of children with a culture positive for NTS was 1.8 (3) years. Overall case fatality was 20.9%. An additional 138 inpatients (0.4%) had a positive culture for typhoidal Salmonella. NTS was identified in 11 outpatients (0.07%), while typhoidal Salmonella was found in 49 outpatients (0.3%). The annual incidence of invasive NTS disease decreased over the study period, but case fatality remained high. Conclusions Although incidence decreased, NTS remained a major cause of invasive bacterial infection and mortality among hospitalized children in Bamako, while typhoidal Salmonella was uncommon. Because 87% of NTS belonged to only 4 serovars, a multivalent vaccine may be an effective strategy to reduce the burden and mortality of invasive NTS.


2012 ◽  
Vol 02 (02) ◽  
pp. 10-14
Author(s):  
Sanjeev H. ◽  
Karnaker Vimal K. ◽  
Pai Vijay ◽  
Pai Asha K. B. ◽  
Rai Rekha ◽  
...  

AbstractInfectious keratitis world wide are a leading cause of ocular morbidity and blindness. A large number of filamentous fungi, Yeasts and Zygomycetes have been incriminated as the causative agent of mycotic keratitis. Early diagnosis and treatment is important in preventing complications like corneal perforation, scleral spread and endopthalmitis. The present study was conducted to elucidate the epidemiological features of mycotic keratitis and study the fungal profile of mycotic keratitis of patients attending our hospital, which is situated on the coastal area of Karnataka.A total of 127 patients with infectious keratitis were investigated between January 2009 to June 2010. Corneal scraping was obtained from 127 patients under aseptic precaution. The scraping was subjected to 10% KOH wet mount, Gram's staining and culture. Of the total 127 patients suspected of having infectious keratitis, 44 (34.65%) were found to be positive for fungal aetiology. Of these, 40(90.90%) cases were positive on direct microscopy for fungal elements and 26(59.09%) cases showed growth on culture after incubation for 2-8 days. In 14 (31.81%) cases, the culture was found to be sterile despite positive direct microscopic findings, but the results were consistent with clinical findings. Positive culture was obtained in 4(09.09%) cases where direct microscopy was found to be negative. The commonest fungi isolated were Aspergillus species (61.5%)Mycotic keratitis continues to be an important cause of ocular morbidity, predominantly among rural population. Prompt diagnosis and early institution of antifungal therapy may limit the ocular morbidity and the sequelae of infectious keratitis. As the manifestation of mycotic keratitis is often confusing, a high degree of suspicion with sound knowledge of predisposing factors and microbiological confirmation is very essential to initiate appropriate therapy.


2019 ◽  
Vol 57 (6) ◽  
Author(s):  
Thomas Kellner ◽  
Brendon Parsons ◽  
Linda Chui ◽  
Byron M. Berenger ◽  
Jianling Xie ◽  
...  

ABSTRACTAlthough enteric multianalyte syndromic panels are increasingly employed, direct comparisons with traditional methods and the inclusion of host phenotype correlations are limited. Luminex xTAG gastrointestinal pathogen panel (GPP) and culture results are highly concordant. However, phenotypic and microbiological confirmatory testing raises concerns regarding the accuracy of the GPP, especially forSalmonellaspp. A total of 3,089 children with gastroenteritis submitted stool specimens, rectal swab specimens, and clinical data. The primary outcome was bacterial pathogen detection agreement for shared targets between culture and the Luminex xTAG GPP. Secondary analyses included phenotype assessment, additional testing of GPP-negative/culture-positive isolate suspensions with the GPP, and in-house and commercial confirmatory nucleic acid testing of GPP-positive/culture-negative extracts. The overall percent agreement between technologies was >99% for each pathogen.Salmonellaspp. were detected in specimens from 64 participants: 12 (19%) by culture only, 9 (14%) by GPP only, and 43 (67%) by both techniques. Positive percent agreement forSalmonellaspp. was 78.2% (95% confidence interval [CI], 64.6%, 87.8%). Isolate suspensions from the 12 participants with specimens GPP negative/culture positive forSalmonellatested positive by GPP. Specimens GPP positive/culture negative forSalmonellaoriginated in younger children with less diarrhea and more vomiting. GPP-positive/culture-negative specimen extracts tested positive using additional assays for 0/2Campylobacter-positive specimens, 0/4Escherichia coliO157-positive specimens, 0/9Salmonella-positive specimens, and 2/3Shigella-positive specimens. For both rectal swab and stool samples, the median cycle threshold (CT) values, determined using quantitative PCR, were higher for GPP-negative/culture-positive samples than for GPP-positive/culture-positive samples (for rectal swabs, 36.9 [interquartile range {IQR}, 33.7, 37.1] versus 30.0 [IQR, 26.2, 33.2], respectively [P = 0.002]; for stool samples, 36.9 [IQR, 33.7, 37.1] versus 29.0 [IQR, 24.8, 30.8], respectively [P = 0.001]). GPP and culture have excellent overall agreement; however, for specific pathogens, GPP is less sensitive than culture and, notably, identifies samples false positive forSalmonellaspp.


Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 4569-4569
Author(s):  
Hyery Kim ◽  
Ji Won Lee ◽  
Hyoung Jin Kang ◽  
Kyung Duk Park ◽  
Hee Young Shin ◽  
...  

Introduction Bloodstream infection (BSI) is one of the most serious complications in patients undergoing hematopoietic stem cell transplantation (HSCT). Early detection and optimal antimicrobial therapy according to antimicrobial susceptibilities is important. This study is to assess the utility of surveillance cultures in predicting invasive pathogens when bacteremia occurs in HSCT patients. Patients & Methods Microbial and susceptibility results of surveillance cultures from patients who underwent HSCT from December, 1999 to May, 2013 in our institution were retrospectively reviewed. A total of 612 transplantations in 527 patients were evaluated (309 allogeneic, 303 autologous). Surveillance cultures were obtained weekly from the day of admission (d-9 or d-10) to the day of neutrophil over 1,000/uL. Five cultures were taken as one set by aseptic cotton swabs at the different body sites; axilla, external auditory canal, throat (posterior pharyngeal wall), nasal cavity and anus. As supportive preventions for infection, patients gargled with sodium bicarbonate solution and took showers every day with decontaminated water during admission. Results Total 10,180 cultures were done in all patients, and average 16.6 cultures were done in one HSCT. The first set of cultures was done in all 612 HSCTs (immediate after admission), the second in 579 HSCTs, and the third in 450 HSCTs, respectively. Positive culture rates were highest in the first set of cultures; axilla 80%, ear 33.3%, throat 98.3%, nasal 53.5%, and anus 45%. Although positive culture rates of four other sites were decreasing in sequential cultures, those of throat cultures were the highest among five body sites and sustained through 1st to 5th sets (median 62%, range 40∼98.5%). The most common microbes were Staphylococcus epidermidis, Streptococcus species, viridans group and Staphylococcus hominis. Almost all cases of Staphylococcus were methicillin resistant (95%). There was no significant difference in culture positive rates and microbial results between allogeneic and autologous groups or between different stem cell sources or different intensities of conditioning. Forty-four patients were diagnosed with BSI. Among those, ten patients showed the same organisms with identical susceptibilities in blood and surveillance cultures (Table). Two patients died from BSI, and in both cases, the organisms were resistant to the usual broad-spectrum antibiotics. The positive culture site of surveillance in these patients included throat, and 7 out of 10 patients showed earlier proven results of the same organisms in throat cultures. Conclusion In surveillance cultures other than blood, throat was the highest culture positive site. Although most of the organisms from surveillance cultures were normal flora, to the patients who showed fever with suspicious BSI, prior throat cultures could offer important information to choose early directed antibiotics. If BSI was suspected and there were resistant organisms in prior throat surveillances, rapid addition of susceptible antibiotics to those organisms could be considered. Disclosures: No relevant conflicts of interest to declare.


2017 ◽  
Vol 56 (2) ◽  
Author(s):  
Jie Liu ◽  
Mathieu Almeida ◽  
Furqan Kabir ◽  
Sadia Shakoor ◽  
Shahida Qureshi ◽  
...  

ABSTRACTThe underestimation ofShigellaspecies as a cause of childhood diarrhea disease has become increasingly apparent with quantitative PCR (qPCR)-based diagnostic methods versus culture. We sought to confirm qPCR-based detection ofShigellavia a metagenomics approach. Three groups of samples were selected from diarrheal cases from the Global Enteric Multicenter Study: nineShigellaculture-positive and qPCR-positive (culture+qPCR+) samples, nine culture-negative but qPCR-positive (culture−qPCR+) samples, and nine culture-negative and qPCR-negative (culture−qPCR−) samples. Fecal DNA was sequenced using paired-end Illumina HiSeq, whereby 3.26 × 108± 5.6 × 107high-quality reads were generated for each sample. We used Kraken software to compare the read counts specific to “Shigella” among the three groups. The proportions ofShigella-specific nonhuman sequence reads between culture+qPCR+(0.65 ± 0.42%) and culture−qPCR+(0.55 ± 0.31%) samples were similar (Mann-Whitney U test,P= 0.627) and distinct from the culture−qPCR−group (0.17 ± 0.15%,P< 0.05). The read counts of sequences previously targeted byShigella/enteroinvasiveEscherichia coli(EIEC) qPCR assays, namely,ipaH,virA,virG,ial,ShET2, andipaH3, were also similar between the culture+qPCR+and culture−qPCR+groups and distinct from the culture−qPCR−groups (P< 0.001). Kraken performed well versus other methods: its precision and recall ofShigellawere excellent at the genus level but variable at the species level. In summary, metagenomic sequencing indicates thatShigella/EIEC qPCR-positive samples are similar to those ofShigellaculture-positive samples inShigellasequence composition, thus supporting qPCR as an accurate method for detectingShigella.


1998 ◽  
Vol 36 (5) ◽  
pp. 1236-1239 ◽  
Author(s):  
S. Nelson ◽  
A. Matlow ◽  
G. Johnson ◽  
C. Th’ng ◽  
M. Dunn ◽  
...  

A PCR-based test was optimized for the detection ofUreaplasma urealyticum from neonatal respiratory specimens, with primers directed against the multiple-banded antigen gene (L. J. Teng, X. Zheng, J. I. Glass, H. Watson, J. Tsai, and G. H. Cassell, J. Clin. Microbiol. 32:1464–1469, 1994). Endotracheal tube aspirates (225) from 103 low-birth-weight neonates (<1,250 g) were taken, when possible, at days 0, 4, and 14 after birth and examined by culture and by PCR. Of 77 specimens positive by either method, 73 were detected by PCR and 60 were detected by culture. Overall, 36% of the neonates were positive for U. urealyticum by either method. Of 16 patients with PCR-positive–culture-negative results, 13 had positive cultures at another sampling point, and one additional patient had a twin with positive cultures. Of 11 patients with day 0 specimens positive by PCR alone, 9 subsequently became culture positive, demonstrating the utility of this test in early detection. Multiple serovars were present in over 50% of positive specimens, with serovars 3 and 14 in combination being most prevalent. The amplicon size generated from the specimen by PCR correctly predicted the biovars isolated in over 85% of positive specimens. Thus, this PCR test was valuable in allowing early detection of U. urealyticum in neonatal respiratory specimens, as well as in providing biovar information.


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