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16th ¡CID Abstracts/International Journal of Infectious Diseases 2IS (2014) 1-460
Results: Addition of a soluble cocktail containing six protease inhibitors to a culture abolished the ability of B. pseudomallei to grow on ferritin as sole iron source. Addition of individual proteases contained in the cocktail revealed that two of them, AEBSF (4-[2-aminoethyl] benzene sulfonyl fluoride) and EDTA exhibited the most potent effect. These data are consistent with the previous finding that B. cenocepacia employs a serine protease for ferritin iron acquisition. Mutants that had all seven serine proteases individually deleted were successfully constructed. All mutants were still able to utilize ferritin as sole iron source at rates indistinguishable from the parent strain. The most plausible explanation for this observation is that B. pseudomallei does not employ a serine protease for ferritin iron acquisition.
Conclusion: We have provided conclusive evidence that ferritin-iron acquisition by B. pseudomallei involves proteolytic degradation of ferritin but the protease(s) and other factors, e.g. transporters, involved in this process remain to be identified. Defining a ferritin-iron acquisition pathway will substantially alter our current view of iron acquisition mechanisms in Gram-negative bacteria and provide a more complete picture of the pathogenesis of infection with B. pseudomallei.
http://dx.doi.org/10.1016/_j.ijid.2014.03.n25 Type: Poster Presentation
Final Abstract Number: 58.020 Session: Bacterial Infections Date: Saturday, April 5,2014 Time: 12:45-14:15 Room: Ballroom
Invasive Salmonella typhimurium populations from Sub-Saharan Africa: Transmission and adaptation dynamics
C.K. Okoro1, R.A. Kingsley1, L. Barquist1, H.R. Simon1, T.R.Connor1, M.Arends2, J. Parkhill1, G. Dougan 1
1 Wellcome Trust Sanger Institute, Cambridge, United Kingdom
2 University of Cambridge, Cambridge, United Kingdom
Background: The emergence of invasive non-typhoidal Salmonella (iNTS) disease across sub-Saharan Africa has been associated with two related lineages of S. Typhimurium which are of multi locus sequence type ST313. The expansion of both lineages has a temporal association with the HIV pandemic and antibiotic usage.
Methods & Materials: Whole genome sequences of ST313 S. Typhimurium were probed for evidence of genome degradation in the form of non-synonymous mutations, frameshift mutations and deletions. Phenotypic microarrays, RNA-sequencing and murine infection models were used to investigate differences in the phe-notype of the isolates from the sub-Saharan African lineages in comparison to gastroenteritis-associated strains.
Results: The results provide evidence that lineage-specific genome degradation, with some similarities to that observed in human S. Typhi, occurred throughout the evolution of these two lineages. Both lineages exhibited altered metabolic potential exemplified by the ability to metabolise alternative carbon sources and different virulence potential in mice.
Conclusion: These results identify likely adaptive changes that may have underpinned the emergence of these lineages and aided their adaptation to immunocompromised humans.
http://dx.doi.org/10.1016/j.ijid.2014.03.1126 Type: Poster Presentation
Final Abstract Number: 58.021 Session: Bacterial Infections Date: Saturday, April 5,2014 Time: 12:45-14:15 Room: Ballroom
Healthcare-associated, community-acquired and hospital-acquired Gram-negative bacteremias in a Turkish referral hospital
D.Unalan1, E.E. Tutuncu1, D.B. Ozturk2, D. Erdim1, G. Gulen1, Y. Gurbuz1, I. Sencan1
1 SB Diskapi Yildirim Beyazit Training and Research Hospital, Ankara, Turkey, Ankara, Turkey
2 SB Ulucanlar Eye Training and Research Hospital, Ankara, Turkey
Background: Bloodstream infections (BSIs) due to gramnegative bacteria are an important cause of sepsis and septic shock that are associated with a high rate of morbidity and mortality. The aim of the present study was to evaluate the differences in the clinical and microbiological characteristics and outcomes of community-acquired, hospital-acquired and healthcare-associated gram-negative bacteremias (GNBs).
Methods & Materials: A prospective cohort study was carried out over a 36-month period in a tertiary referral hospital inTurkeyand patients with gram-negative bacteremia were included. Those patients with a prior hospitalization within 90 days, ongoing chemotherapy, hemodialysis, home intravenous therapy, wound care and residence in a long-term care facility were classified as having healthcare-associated BSIs.
Results: Among 151 patients, 57 (37.7%) had bacteremia within two days of admission and classified as having community-acquired BSIs. Forty (70%) of these patients were found to be healthcare-associated.The remaining 94 patients (62.3%) were considered to have hospital-acquired infections.
Malignancies were more common in patients with healthcare associated and hospital-acquired GNBs than in patients with community-acquired infections (42.5%, 45.7% and 5.8% respectively).
Nearly all (88.2%) cases of community-acquired bacteremia were originated from urinary tract infections (UTIs). UTIs were the origin of bacteremia in 55% of health-care associated and 20% of hospital-acquired GNBs.
E. coli was the most common pathogen in both community-acquired and health-care associated GNBs (64.7% and 72.5%, respectively), whereas accounted for 34% of hospital-acquired cases. Acinetobacter spp. (22.3%) was the second most frequent pathogen in patients with hospital-acquired GNBs.
The third-generation cephalosporin resistance rates were similar in patients with community-acquired and health-care associated GNBs (52.9% and 55%, respectively) and carbapenem resistance was not detected among these patient groups. Ceftria-xone and imipenem resistance was found to be 74.4% and 32.9% respectively in patients with hospital-acquired GNBs.
Fatality rates were not significantly different between community-acquired and health-care associated GNBs (11.7%
16th ICID Abstracts/International Journal of Infectious Diseases 2IS (2014) 1-460
and 17.5%, respectively, p = 0.587), but was higher (58.5%) in patients with hospital-acquired GNBs.
Conclusion: Although there was a difference in comor-bid conditions, health-care associated GNBs were similar to community-acquired infections in terms of pathogens and susceptibility patterns in our hospital.
tance of development of effective bivalent typhoid and paratyphoid vaccine.
http://dx.doi.org/10.1016/j.ijid.2014.03.1128 Type: Poster Presentation
http://dx.doi.org/10.1016/_j.ijid.2014.03.n27 Type: Poster Presentation
Final Abstract Number: 58.022 Session: Bacterial Infections Date: Saturday, April 5,2014 Time: 12:45-14:15 Room: Ballroom
Characterization of the induced immune responses, clinical presentation and antibiotic susceptibility pattern in Bangladeshi S. paratyphi A bacteremic patients
F. Khanam1, F. Qadri2
1 icddrb, Dhaka, Bangladesh
2 International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), Dhaka, Bangladesh
Background: Salmonella enterica serotype Paratyphi A (S. Paratyphi A) is responsible for one-fifth of enteric fever cases in Asia and the proportion of infection in travelers is also increasing. Despite this, data on immune responses in patients with S. Paratyphi A bacteremia is scarce. Here we have described S. Paraty-phi A specific mucosal and systemic immune responses induced inpatients and compared with the responses in healthy controls (HC). We have presented symptoms of the patients and sensitivity pattern of the isolated strains
Methods & Materials: Blood was collected from patients at enrolment (day 1) and then 7 (day 2) and 21 (day 3) days later. Microbiological culture of blood was done by using a BacT/Alert automated system and organism was identified biochemically and by slide agglutination test. Antimicrobial susceptibility test was carried out by disc diffusion method. The mucosal and systemic immune responses were measured using lymphocyte culture supernatant and plasma respectively
Results: The patients with paratyphoid fever (n = 25) had high grade fever (median temp 38.9oC) and more commonly presented with diarrhea 17 (68%) and headache 12 (48%). Among 25 isolated strains, a higher level of reduced susceptibility was found to ciprofloxacin (98%) and azythromycin (68%), whereas 25 (100%) were resistant to nalidixid acid. All isolated strains were sensitive to third generation cephalosporin (cefixime, ceftazidime and ceftriaxone). The membrane preparation (MP) specific IgA antibody response in lymphocyte culture supernatant was significantly higher at three time points than healthy control (P< 0.0001). The patients developed significantly higher response than healthy control at convalescent stages for plasma-MP-IgA (day 2 Vs HC; P =0.0078) and IgM (day 2 Vs HC; P =0.0168 and (day 3 Vs HC; P = 0.0298), while the response was higher at three stages of disease for IgG (P<0.0001).
Conclusion: The findings of the study indicate that patients with paratyphoid fever generate a robust humoral immune responses and this demonstration will be helpful in evaluating the responses induced in vaccine recipients. The emergence of S. Paratyphi A strains with resistance to commonly used antibiotic signifies the complication in selecting appropriate antibiotic and the impor-
Final Abstract Number: 58.024 Session: Bacterial Infections Date: Saturday, April 5, 2014 Time: 12:45-14:15 Room: Ballroom
Genotyping and Investigation of group B Streptococci by PCR and culture methods in vaginal culture samples requested from women admitted to clinic of gynecology and obstetrics by any reason
F. Alp, D. Findik, H. Turk Dagi, U. Arslan Selcuk University Faculty of Medicine, Konya, Turkey
Background: The aim of this study was to investigate the Group B Streptococci by PCR and Culture methods in vaginal culture samples requested from women admitted to the Clinic of Gynecology and Obstetrics and to genotype the isolates.
Methods & Materials: All of the 500 samples were incubated in the LIM broth over night and then they were subcultered on the chromID Strepto B agar medium The GBS positivity was confirmed by using CAMP and latex agglutination tests. PCR and latex agglutination assays were carried out for all LIM broths. Antimicrobial susceptibility testing for all GBS isolates was carried out by using instructions of CLSI. PFGE iwas used to characterize clonal relationship among GBS isolates.
Results: In this study, colonization with GBS were detected in 68 women (13.6%), of which 21 (9.76%) were pregnant and 47 (17.19%) were nonpregnant. A statistically significant difference was observed between pregnant and non-pregnant women (p < 0.05), and between GBS colonization and EMR (p = 0.022). Sixty five (13%) GBS isolates grew by cultivation technique. Sensitivity of cultivation was found as 95.6%, while sensitivity, PPD and NPD were 100%, 100%, 99.3% respectively. Latex agglutination test posi-tivity of Lim broth for GBS was 14% and PCR positivity for GBS was 12.4%.. While all strains were susceptible to penicillin, ceftriaxone, linezolid and vancomycin, 87.3% of strains were resistant to tetra-cycline. Thirteen different pulso-types (PT) were determined in the PFGE study of 63 strains isolated.
Conclusion: In the light of the data obtained from the study, GBS latex agglutination test of LIM broth media was found faster and more sensitive than cultivation method to demonstrate GBS colonization. The PCR assay, while being fast, seems to be disadvantageous in being costly and requires experienced staff. It is thought that rectovaginal screening of GBS in pregnant women at 35th-37th weeks of gestation and determination of colonization as soon as possible will reduce neonatal GBS infections and mortality rates in Turkey. The need for an immediate preparation of national guidelines for prophylaxis application program is now well understood.
http://dx.doi.org/10.1016/j.ijid.2014.03.1129
