bluuebunny/crossref_metadata_2025_split huggingface dataset:
The
Staphylococcus aureus rsbW
(
orf159
) Gene Encodes an Anti-Sigma Factor of SigB
Authors: Miyazaki Eishi , Chen Jong-Min , Ko Chiew , Bishai William R. 
Published: December 2019

ABSTRACT

SigB, a newly discovered alternative sigma factor of
Staphylococcus aureus
, has been shown to play an important role in stress responses and the regulation of virulence factors. The
rsbW
(
orf159
) gene is immediately upstream of
sigB
. Its gene product is homologous to
Bacillus subtilis
RsbW which under appropriate conditions binds to
B. subtilis
SigB and functions as an anti-sigma factor or negative posttranslational regulator. To define the function of
S. aureus
RsbW, both the
S. aureus
SigB and RsbW proteins were expressed in
Escherichia coli
and purified. Cross-linking experiments with these purified proteins revealed that RsbW was capable of specific binding to SigB. In an in vitro transcription runoff assay, RsbW prevented SigB-directed transcription from the
sar
P3 promoter, a known SigB-dependent promoter, and the inhibitory activity of RsbW was found to be concentration dependent. We also identified SigB promoter consensus sequences upstream of the genes encoding alkaline shock protein 23 and coagulase and have demonstrated SigB and RsbW dependence for the promoters in vitro. These results show that RsbW is a protein sequestering anti-sigma factor of
S. aureus
SigB and suggest that SigB activity in
S. aureus
is regulated posttranslationally.
Virulence Factors of
Escherichia coli
Isolates From Patients with Symptomatic and Asymptomatic Bacteriuria and Neuropathic Bladders Due to Spinal Cord and Brain Injuries
Authors: Hull Richard A. , Rudy Delbert C. , Wieser Inge E. , Donovan William H. 
Published: December 2019

ABSTRACT

Chronic bacteriuria is a common occurrence among spinal-cord injury patients and others with neuropathic bladders. If bacteria are present in the urinary tract, the patient may develop symptoms of infection or remain asymptomatic. We have compared virulence properties of 28
Escherichia coli
isolates from patients with symptomatic urinary tract infections (UTI) and 29
E. coli
isolates from patients with asymptomatic bacteriuria (ABU). Bacteria from patients with symptomatic UTI were more likely to be hemolytic than isolates from patients with ABU (
P
= 0.05) or fecal isolates obtained from healthy volunteers (
P
< 0.001). Bacteria from patients with symptomatic UTI were also more likely than strains isolated from patients with ABU (
P
= 0.08) or fecal strains (
P
< 0.001) to exhibit
d
-mannose-resistant hemagglutination of human erythrocytes. The results suggest that
E. coli
isolates from nonimmunocompromised patients who require intermittent catheterization and who develop symptomatic UTI may be distinguished from bacteria recovered from patients who remain asymptomatic and possibly from normal fecal
E. coli.
Clinical Application of PCR-Restriction Enzyme Pattern Analysis for Rapid Identification of Aerobic Actinomycete Isolates
Authors: Wilson Rebecca W. , Steingrube Vincent A. , Brown Barbara A. , Wallace Richard J. 
Published: December 2019

ABSTRACT

The accuracy and practicality of PCR-restriction enzyme pattern analysis (PRA) for routine identification of aerobic actinomycete clinical isolates were evaluated for 299 cultures submitted to the Mycobacteria/Nocardia Laboratory at the University of Texas Health Center at Tyler. PRA identification using an amplified 439-bp segment (amplicon) of the 65-kDa heat shock protein gene was compared to identification by traditional methods, including growth characteristics, susceptibility patterns, biochemical testing, and high-performance liquid chromatography analysis. Microbiological examination of six cultures ruled out aerobic actinomycetes, and they were omitted from the study. Amplicons were analyzed with
Bst
EII,
Hae
III,
Msp
I,
Hin
fI, and
Bsa
HI. When necessary,
Aci
I,
Hha
I, and
Nar
I were also used. From March 1995 through May 1997 (27 months), 274 of the remaining 293 (93.5%) isolates were accurately identified by PRA. Major diagnostic groups included 170 mycobacteria, 93 nocardiae, and 30 other aerobic actinomycetes. Mixed cultures were readily recognized by PRA, including a wound culture that contained two
Nocardia
taxa that were indistinguishable morphologically.
Mycobacterium mucogenicum
was identified in three cultures heavily contaminated with gram-positive cocci. The 19 isolates that produced PRA patterns that did not match those in the current PRA database were differentiated into 8
Mycobacterium
species and 11 other aerobic actinomycetes by the presence or absence of
Bst
EII recognition sites. Identification of 15 of these 19 isolates was also equivocal by traditional methods. PRA results were reportable within 2 to 5 working days and were as accurate as and faster and less expensive to obtain than those of traditional methods.
Assessment of Three In Vitro Tests and an In Vivo Test for Chloroquine Resistance in
Plasmodium falciparum
Clinical Isolates
Authors: Bickii Jean , Basco Leonardo K. , Ringwald Pascal 
Published: December 2019

ABSTRACT

Three in vitro assays (the isotopic semimicrotest [700 μl per well; 24-well plates], the isotopic microtest [200 μl per well; 96-well plates], and the rapid in vitro test) and the standard in vivo test for chloroquine resistance were compared for 99 clinical isolates of
Plasmodium falciparum
obtained from symptomatic African patients. The 50% inhibitory concentrations determined by the two isotopic tests were similar and were highly correlated (
r
= 0.965;
P
< 0.05), showing a high concordance between the semimicrotest and the microtest. There was a moderate agreement between these two isotopic tests and the in vivo test. Most of the discordant results were probably due to host factors, including reinfections, pharmacokinetic variations, and immunologic response, which are eliminated in in vitro assays. The rapid in vitro test based on the inhibition of chloroquine efflux in the presence of verapamil was poorly concordant with the other tests. Despite some discordant results, isotopic in vitro assays are useful to characterize the phenotypes of individual isolates without the interference of host factors and are complementary to in vivo evaluation of drug efficacy. However, in vitro assays need to be standardized to allow direct comparison of results between different laboratories.
First Report of a Human Isolate of
Erwinia persicinus
Authors: O’Hara Caroline M. , Steigerwalt Arnold G. , Hill Bertha C. , Miller J. Michael , Brenner Don J. 
Published: December 2019

ABSTRACT

Erwinia persicinus
was first described in 1990 after being isolated from a variety of fruits and vegetables, including bananas, cucumbers, and tomatoes. In 1994, it was shown to be the causative agent of necrosis of bean pods. We now report the first human isolate of
E. persicinus
. The strain was isolated from the urine of an 88-year-old woman who presented with a urinary tract infection. By the hydroxyapatite method, DNA from this strain was shown to be 94.5% related at 60°C and 86% related at 75°C to the type strain of
E. persicinus
. The biochemical profile of
E. persicinus
is most similar to those of
Erwinia rhapontici
,
Pantoea agglomerans
, and
Enterobacter
species. It is negative in tests for lysine, arginine, ornithine, dulcitol, and urea. It is motile and positive in tests for
d
-sorbitol and sucrose. It is susceptible to the expanded-spectrum cephalosporins, aminoglycosides, and fluoroquinolones, but it is resistant to ampicillin, ticarcillin, and cefazolin.
Sporadic Emergence of
Klebsiella pneumoniae
Strains Resistant to Cefepime and Cefpirome in Greek Hospitals
Authors: Tzouvelekis L. S. , Tzelepi E. , Prinarakis E. , Gazouli M. , Katrahoura A. , Giakkoupi P. , Paniara O. , Legakis N. J. 
Published: December 2019

ABSTRACT

The sporadic emergence of
Klebsiella pneumoniae
strains resistant to cefepime and cefpirome was observed in Greek hospitals during 1996. Examination of six epidemiologically distinct strains and clones selected in vitro provided indications that resistance is due to the cooperation of decreased outer membrane permeability and hydrolysis of the cephalosporins by SHV-5 β-lactamase, which was produced in large amounts.
Evaluation of Screening and Commercial Methods for Detection of Methicillin Resistance in Coagulase-Negative Staphylococci
Authors: Hussain Zafar , Stoakes Luba , Lannigan Robert , Longo Susan , Nancekivell Barbara 
Published: December 2019

ABSTRACT

The National Committee for Clinical Laboratory Standards recommends 48 h of incubation by the oxacillin salt agar screen (OSAS) method for the detection of methicillin-resistant coagulase-negative staphylococci (CoNS). An earlier identification of methicillin resistance is desirable. The time to detection of the
mecA
gene by PCR was compared with the times to detection by OSAS, by the oxacillin disk diffusion (ODD) method, and with MicroScan Gram Positive Combo type 6 panels (MicroScan Inc. Sacramento, Calif.) and Vitek GPS-SA cards (bioMérieux Vitek Inc., Hazelwood, Mo.). The combination of the Vitek card and the ODD method detected 92 of 99 methicillin-resistant strains of CoNS at 24 h; however, 6
mecA
-positive strains were phenotypically methicillin susceptible. We conclude that most methicillin-resistant CoNS can be detected and the results can be reported after overnight incubation by a combination of methods.
Low Sensitivity of Peripheral Blood Smear for Diagnosis of Subclinical Visceral Leishmaniasis in Human Immunodeficiency Virus Type 1-Infected Patients
Authors: Delgado J. , Pineda J. A. , Macías J. , Regordán C. , Gallardo J. A. , Leal M. , Sanchez-Quijano A. , Lissen E. 
Published: December 2019

ABSTRACT

The peripheral blood smear is an easy method for the diagnosis of symptomatic visceral leishmaniasis (VL) in human immunodeficiency virus type 1 (HIV-1)-infected patients. However, its efficiency in diagnosing subclinical VL remains unknown. In this study,
Leishmania
amastigotes were seen in blood smears from 1 of 13 HIV-1-positive individuals with subclinical VL. This shows that this procedure is not suitable for subclinical-VL diagnosis.
Comparison of ATB Staph, Rapid ATB Staph, Vitek, and E-Test Methods for Detection of Oxacillin Heteroresistance in Staphylococci Possessing
mecA
Authors: Frebourg Noëlle Barbier , Nouet Delphine , Lemée Ludovic , Martin Emmanuelle , Lemeland Jean-François 
Published: December 2019

ABSTRACT

The performance characteristics of the E-test (AB Biodisk, Solna, Sweden), the ATB Staph, the Rapid ATB Staph, and the Vitek GPS-503 card (bioMérieux, La Balme Les Grottes, France) methods for the detection of oxacillin resistance in a collection of staphylococci with a high proportion of troublesome strains were evaluated. Sixty-four
Staphylococcus aureus
strains and 76 coagulase-negative staphylococcal strains were tested. All strains were
mecA
positive and were characterized by the oxacillin agar screen plate test; 75 (53.6%) were found to be heterogeneous by a large-inoculum oxacillin disk diffusion assay, and oxacillin MICs for 89 (63.6%) were ≤32 μg/ml. Three (4.7%)
S. aureus
strains and 25 (32.9%) coagulase-negative strains were classified as susceptible by the E-test, as defined by the National Committee for Clinical Laboratory Standards (NCCLS) oxacillin breakpoint (MIC ≤ 2 μg/ml). The ATB Staph method failed to detect oxacillin resistance in 7 (11%)
S. aureus
isolates and 32 (42.1%) coagulase-negative isolates. The MICs for all but six of these discrepant isolates were ≤16 μg/ml. The Rapid ATB Staph method was tested against
S. aureus
strains only and yielded 15 (23.4%) false-susceptible results for strains for which the MICs were ≤32 μg/ml. The Vitek system was the best-performing system, since it failed to detect oxacillin resistance in only 3 (4.7%)
S. aureus
strains and 15 (19.7%) coagulase-negative strains, the MICs for all of which were ≤2 μg/ml. These data indicate that (i) the performance of the two ATB Staph systems can be limited when the prevalence of borderline-heteroresistant staphylococci is high and (ii) the unreliability of the E-test and the Vitek methods for detecting resistant coagulase-negative strains might be reduced by the potential revision of the oxacillin breakpoint currently recommended by the NCCLS.
Prospective Investigation of Cryptic Outbreaks of
Salmonella agona
Salmonellosis
Authors: Taylor Jeffery P. , Barnett Ben J. , del Rosario Lemuel , Williams Karen , Barth Suzanne S. 
Published: December 2019

ABSTRACT

The number of
Salmonella agona
isolates reported annually in Texas from 1992 through 1994 ranged from 14 to 21. An increase in incidence of
S. agona
infections was noted in the fall of 1995. Pulsed-field gel electrophoresis (PFGE) analysis identified prospectively two possible cryptic outbreaks caused by an indistinguishable strain which was isolated from 18 of 59 patients who were culture positive from March through December 1995. These 18 patients had onset of illness from 20 May through 3 October 1995. Eight individuals resided in the Austin area, eight resided in San Antonio, and two resided in Houston; none had attended a common social gathering or owned common pets. Six patients in San Antonio and one patient from Houston recalled eating food items from the same Mexican food restaurant in San Antonio.
S. agona
organisms with the same PFGE profile were isolated from machacado, an air-dried, raw beef product prepared at the restaurant. The machacado had been shredded in a kitchen blender which was the probable source for cross-contamination of other food items. Five patients in Austin reported eating at a popular Mexican food restaurant in Austin. Improperly prepared machacado also may have been served at the Austin restaurant; however, sufficient quantities of machacado were not available for analysis. PFGE was essential in determining whether the cases constituted outbreaks and was invaluable in guiding the epidemiological investigation.
Direct Antimicrobial Susceptibility Testing of Gram-Negative Bacilli in Blood Cultures by an Electrochemical Method
Authors: Huang Ay Huey , Wu Jiunn Jong , Weng Yu Mei , Ding Hwia Cheng , Chang Tsung Chain 
Published: December 2019

ABSTRACT
Nonfastidious aerobic gram-negative bacilli (GNB) are commonly isolated from blood cultures. The feasibility of using an electrochemical method for direct antimicrobial susceptibility testing of GNB in positive blood cultures was evaluated. An aliquot (10 μl) of 1:10-diluted positive blood cultures containing GNB was inoculated into the Bactometer module well (bioMérieux Vitek, Hazelwood, Mo.) containing 1 ml of Mueller-Hinton broth supplemented with an antibiotic. Susceptibility tests were performed in a breakpoint broth dilution format, with the results being categorized as resistant, intermediate, or susceptible. Seven antibiotics (ampicillin, cephalothin, gentamicin, amikacin, cefamandole, cefotaxime, and ciprofloxacin) were used in this study, with each agent being tested at the two interpretive breakpoint concentrations. The inoculated modules were incubated at 35°C, and the change in impedance in each well was continuously monitored for 24 h by the Bactometer. The MICs of the seven antibiotics for each blood isolate were also determined by the standardized broth microdilution method. Of 146 positive blood cultures (1,022 microorganism-antibiotic combinations) containing GNB tested by the direct method, the rates of very major, major, and minor errors were 0, 1.1, and 2.5%, respectively. The impedance method was simple; no centrifugation, preincubation, or standardization of the inocula was required, and the susceptibility results were normally available within 3 to 6 h after inoculation. The rapid method may allow proper antimicrobial treatment almost 30 to 40 h before the results of the standard methods are available.
Incidence of
Toxoplasma gondii
Infection in 35,940 Pregnant Women in Norway and Pregnancy Outcome for Infected Women
Authors: Jenum Pål A. , Stray-Pedersen Babill , Melby Kjetil K. , Kapperud Georg , Whitelaw Andrew , Eskild Anne , Eng Jan 
Published: December 2019

ABSTRACT

From 1992 to 1994 a screening program for detection of specific
Toxoplasma gondii
antibodies involving 35,940 pregnant women was conducted in Norway. For women with serological evidence of primary
T. gondii
infection, amniocentesis and antiparasitic treatment were offered. The amniotic fluid was examined for
T. gondii
by PCR and mouse inoculation to detect fetal infection. Infants of infected mothers had clinical and serological follow-up for at least 1 year to detect congenital infection. Of the women 10.9% were infected before the onset of pregnancy. Forty-seven women (0.17% among previously noninfected women) showed evidence of primary infection during pregnancy. The highest incidence was detected (i) among foreign women (0.60%), (ii) in the capital city of Oslo (0.46%), and (iii) in the first trimester (0.29%). Congenital infection was detected in 11 infants, giving a transmission rate of 23% overall, 13% in the first trimester, 29% in the second, and 50% in the third. During the 1-year follow-up period only one infant, born to an untreated mother, was found to be clinically affected (unilateral chorioretinitis and loss of vision). At the beginning of pregnancy 0.6% of the previously uninfected women were falsely identified as positive by the Platelia Toxo-IgM test, the percentage increasing to 1.3% at the end of pregnancy. Of the women infected prior to pregnancy 6.8% had persisting specific immunoglobulin M (IgM). A positive specific-IgM result had a low predictive value for identifying primary
T. gondii
infection.
Hepatitis C in a Hemodialysis Unit: Molecular Evidence for Nosocomial Transmission
Authors: Le Pogam S. , Le Chapois D. , Christen R. , Dubois F. , Barin F. , Goudeau A. 
Published: December 2019

ABSTRACT
This study reports four cases of transmission of the rare hepatitis C virus genotype 4 which occurred in a hemodialysis unit and originated from a single source of infection. Phylogenetic analyses performed with the NS5b domain showed that all four patients with secondary infections were infected with virus strains very similar to that of the index patient. Cross infections probably resulted from breaches in safety precautions and lack of dialysis machine sterilization.
Isolation of
Enterobacter intermedium
from the Gallbladder of a Patient with Cholecystitis
Authors: O’Hara Caroline Mohr , Steward Christine D. , Wright Joan L. , Tenover Fred C. , Miller J. Michael 
Published: December 2019

ABSTRACT

We describe the isolation and identification of
Enterobacter intermedium
from the gallbladder of a patient with cholecystitis. There have been only four documented isolations of this organism from humans; it normally occurs in surface water and unpolluted soils. The identification was initially made by a MicroScan Walk/Away system with a Neg Combo 18 conventional identification-susceptibility panel. The organism is susceptible to the aminoglycosides and imipenem but resistant to the cephalosporins and ciprofloxacin.
Confirmation of Nosocomial Transmission of Hepatitis C Virus by Phylogenetic Analysis of the NS5-B Region
Authors: Norder Heléne , Bergström Åsa , Uhnoo Ingrid , Aldén Jöran , Weiss Lars , Czajkowski Jan , Magnius Lars 
Published: December 2019

ABSTRACT
Four hepatitis C virus transmission chains at three dialysis units were disclosed by limited sequencing; three of these were disclosed by analysis of the NS5-B region of the genome. Dialysis on the same shift as that during which infected patients were dialyzed was the common factor for seven patients in two chains. Two nurses exposed to needle sticks and their sources of infection constituted two other chains. The strains of three chains belonged to subtype 1a and formed clusters with an intrachain variability of 0 to 6 nucleotides compared to 8 to 37 nucleotides for unrelated strains within this subtype. The clusters were supported by bootstrap values ranging from 89 to 100%.
Hepatitis C Virus RNA in Dried Serum Spotted onto Filter Paper Is Stable at Room Temperature
Authors: Abe Kenji , Konomi Nami 
Published: December 2019

ABSTRACT
To overcome the instability of viral RNA, we carried out hepatitis C virus (HCV) RNA detection in dried serum spotted onto filter paper. The spotted serum samples were stored at room temperature and then processed for PCR assay at intervals of 1, 2, 3, and 4 weeks. The results showed that serum HCV RNA is stable in a dried condition, as it was detectable in spotted serum samples stored for 4 weeks at room temperature. Furthermore, although the HCV RNA titer showed an ∼10-fold reduction in virus yield in dried serum stored at room temperature for 4 weeks, the PCR results of frozen serum samples and dried serum samples matched completely. This storage method facilitates transport and analysis by nucleic acid amplification techniques even when freezing conditions are not available.
Colony Variation in
Staphylococcus lugdunensis
Authors: Leung Michael J. , Nuttall Nichalas , Pryce Todd M. , Coombs Geoffrey W. , Pearman John W. 
Published: December 2019

ABSTRACT

Staphylococcus lugdunensis
is being increasingly reported as a pathogen with an outcome resembling that of
S. aureus
rather than coagulase-negative staphylococci. Recent local isolates exhibited colonial variation that delayed identification and interpretation of clinical significance. Until now previous descriptions have not emphasized colonial variation as an important identifying characteristic of
S. lugdunensis
.
Molecular Fingerprinting of
Mycobacterium tuberculosis
Isolates Obtained in Havana, Cuba, by IS
6110
Restriction Fragment Length Polymorphism Analysis and by the Double-Repetitive-Element PCR Method
Authors: Montoro Ernesto , Valdivia José , Leão Sylvia Cardoso 
Published: December 2019

ABSTRACT

Mycobacterium tuberculosis
sputum isolates from 38 patients, obtained in the first 6 months of 1997 in Havana, Cuba, were characterized by IS
6110
restriction fragment length polymorphism (RFLP) analysis and the double-repetitive-element PCR (DRE-PCR) method. Among 41 strains from 38 patients, 24 and 25 unique patterns, and 5 and 4 cluster patterns, were found by the RFLP and DRE-PCR methods, respectively. Patients within two of these clusters were found to be epidemiologically related, while no relation was observed in patients in the other clusters. The DRE-PCR method is rapid, and it was as discriminating as IS
6110
RFLP analysis in identifying an epidemiological association. Its simplicity makes the technique accessible for subtyping of
M. tuberculosis
strains in laboratories not equipped to perform RFLP analysis.
Unreliability of Disc Diffusion Test for Screening for Reduced Penicillin Susceptibility in
Neisseria meningitidis
Authors: Block Colin , Davidson Yehudit , Keller Nathan 
Published: December 2019

ABSTRACT
The 2-U penicillin and 1-μg oxacillin discs proposed for screening meningococci for susceptibility to penicillin were evaluated by using MICs measured by the E test. The discs yielded unacceptably high frequencies of misclassification of susceptibility category and should be abandoned in favor of MIC estimations. An agreed breakpoint for reduced penicillin susceptibility in meningococci is needed for the E test.