bluuebunny/crossref_metadata_2025 huggingface dataset:
Photosynthetic Apparatus in the Green Bacterium
Chloropseudomonas ethylicum
Authors: Holt Stanley C. , Conti S. F. , Fuller R. C.
Published: January 2020

Holt, Stanley
C. (Dartmouth Medical School, Hanover, N.H.), S. F.
Conti, and
R. C.
Fuller
. Photosynthetic apparatus in the green bacterium
Chloro-pseudomonas ethylicum
. J. Bacteriol.
91:
311–323. 1966.—When cells of
Chloro-pseudomonas ethylicum
were broken by ballistic disruption and examined by electron microscopy, vesicles 1,300 to 1,500 A long and 300 to 500 A wide were found to rim the periphery of the cell. Examination of these vesicles obtained by disruption with a French pressure cell and purified by density gradient centrifugation revealed inter-connections between the vesicles. During sonic and Mickle disruption of the cells, chlorophyll was released at a lower rate than soluble cytoplasmic components, but faster than the membrane-bound enzyme succinic dehydrogenase. Unlike the situation that exists in the purple photosynthetic bacteria, it appears that the chlorophyll in the green bacteria is contained as part of a structure which may be differentiated both structurally and functionally from the bacterial cytoplasmic membrane.
Effect of Light Intensity on the Formation of the Photochemical Apparatus in the Green Bacterium
Chloropseudomonas ethylicum
Authors: Holt Stanley C. , Conti S. F. , Fuller R. C.
Published: January 2020

Holt, Stanley
C. (Dartmouth Medical School, Hanover, N.H.), S. F.
Conti, and R. C. Fuller
. Effect of light intensity on the formation of the photochemical apparatus in the green bacterium
Chloropseudomonas ethylicum
. J. Bacteriol.
91:
349–355. 1966.—When the green bacterium
Chloropseudomonas ethylicum
was grown at various light intensities, the formation of the photosynthetic vesicles was found to be an inverse function of the light intensity at which the cells were grown. The specific chlorophyll content of isolated vesicles varied as the light intensity was changed over a wide range. Thus, the regulation of chlorophyll content in
C. ethylicum
in response to a change in light intensity is achieved both by a change in the number of vesicles that are formed and by a change in the specific chlorophyll content of these vesicles.
Concurrent Changes in Transducing Efficiency and Content of Transforming Deoxyribonucleic Acid in
Bacillus subtilis
Bacteriophage SP-10
Authors: Taylor Martha J. , Thorne Curtis B.
Published: January 2020

Taylor, Martha
J. (Fort Detrick, Frederick, Md.),
and Curtis B. Thorne
. Concurrent changes in transducing efficiency and content of transforming deoxyribonucleic acid in
Bacillus subtilis
bacteriophage SP-10. J. Bacteriol.
91:
81–88. 1966.—Spores of
Bacillus subtilis
W-23-S
r
infected with transducing phage SP-10 served as convenient inocula for broth cultures from which transducing phage was harvested. Methods are described for producing highly infected spores. The inoculum level of infected spores in nutrient broth-yeast extract-glucose medium affected the transducing efficiency of SP-10 in lysates of these cultures. Phage in lysates of cultures inoculated with about 10
5
or fewer spores per milliliter transduced 20- to 350-fold more efficiently than did phage in lysates from cultures inoculated with 10
6
to 10
7
spores per milliliter. Transduction frequencies in the order of 10
−5
per plaque-forming unit were obtained routinely, and some infected-spore preparations yielded phage that gave frequencies as high as 10
−4
. The combination of inoculum level and incubation time required to produce the best transducing phage had to be determined empirically for each batch of infected spores. Several possible explanations for the difference between lysates having high (HTE) and those having low (LTE) transducing efficiency were ruled out by special experiments. The hypothesis is presented that some cultural condition resulting from a relatively low inoculum of phage-infected spores favors the incorporation by phage particles of bacterial deoxyribonucleic acid (DNA) in the manner required for the production of transducing phage. Support for this hypothesis is a demonstration, through transformation experiments with DNA extracted from HTE and LTE phage particles, that populations of HTE phage particles yielded significantly more (7 to 27 times) transforming activity per microgram of DNA than did populations of LTE phage.
Toxigenicity of
Clostridium histolyticum
Authors: Nishida Shoki , Imaizumi Masaaki
Published: January 2020

Nishida, Shoki
(Kanazawa University, Kanazawa, Japan),
and Masaaki Imaizumi
. Toxigenicity of
Clostridium histolyticum
. J. Bacteriol.
91:
477–483. 1966.—From 234 soil samples, 21 strains of
Clostridium histolyticum
of different levels of α-toxigenicity were isolated by a new method specially designed for the isolation of this species. The α-toxigenicity of freshly isolated strains and of stock strains was closely associated with the potentiality for sporulation, growth, and smooth-colony formation. The presence of sugars, particularly xylose and arabinose, was inhibitory for growth. A few controversies on the biological properties of this species seem to be due to disregard for the growth-inhibiting effects of these sugars.
Characterization of a Small Proteolytic Enzyme Which Lyses Bacterial Cell Walls
Authors: Ensign J. C. , Wolfe R. S.
Published: January 2020

Ensign
, J. C. (University of Wisconsin, Madison),
and R. S. Wolfe
. Characterization of a small proteolytic enzyme which lyses bacterial cell walls. J. Bacteriol.
91:
524–534. 1966.—An enzyme isolated from a myxobacter possesses both cell-wall lytic and proteolytic activity. The enzyme has been purified over 600-fold and is electrophoretically homogeneous upon cellulose acetate at several
p
H values and upon polyacrylamide gel columns. A single peak was obtained upon ultracentrifugation and density gradient centrifugation. Based upon Sephadex gel filtration, a molecular weight of 8,700 was determined for the enzyme. Albumin and casein were extensively degraded by the enzyme, with approximately one-third of the peptide bonds present in these proteins being hydrolyzed. The enzyme lyses cell walls by hydrolyzing peptide bonds in the glycosaminopeptide.
Specificity and Mechanism of Tetracycline Resistance in a Multiple Drug Resistant Strain of
Escherichia coli
Authors: Izaki Kazuo , Kiuchi Kan , Arima Kei
Published: January 2020

Izaki, Kazuo
(University of Tokyo, Tokyo, Japan),
Kan Kiuchi, and Kei Arima
. Specificity and mechanism of tetracycline resistance in a multiple drug resistant strain of
Escherichia coli
. J. Bacteriol.
91:
628–633. 1966.—A decrease in the uptake of tetracycline occurred concurrently with a rise in the level of resistance of a multiple drug resistant strain of
Escherichia coli
grown in the presence of tetracycline. Although the strain was also resistant to streptomycin and chloramphenicol, growth in the presence of these two antibiotics did not influence the uptake of tetracycline. The induction of resistance, or decreased uptake of tetracycline, was dependent on growth of the organism in the presence of the drug. Decreased uptake of tetracycline could not be induced in a sensitive strain of the same organism under conditions suitable for induction of the resistant strain. The decrease in accumulating power of the resistant organism cultured in the presence of tetracycline does not appear to be due to selection of a resistant strain from cultures containing both resistant and sensitive strains.
Genetic Control of Amino Acid Permeability in
Neurospora crassa
Authors: Lester Gabriel
Published: January 2020

Lester, Gabriel
(Reed College, Portland, Ore.). Genetic control of amino acid permeability in
Neurospora crassa
. J. Bacteriol.
91:
677–684. 1966.—Strains of
Neurospora crassa
resistant to 4-methyltryptophan (4-MT) were isolated from populations of conidia exposed to ultraviolet light. In genetic crosses, 4-MT resistance behaved as a single-gene difference. Resistance to 4-MT could not be attributed to a relaxation of control of the formation or the activity of the enzymes of tryptophan biosynthesis. Growth studies involving tryptophan auxotrophs carrying the aberrant
mt
gene and uptake studies with normal and 4-MT-resistant strains showed that 4-MT resistance could be attributed to an inability of 4-MT-resistant strains to take up tryptophan and its methyl analogues. The
mt
gene is not specific for tryptophan; strains resistant to 4-MT are also resistant to ethionine, and they have a markedly reduced ability to take up serine, leucine, and α-aminoisobutyric acid. No difference was observed between strains carrying either
mt
allele in their ability to take up glucose; also, the uptake of anthranilic acid or of indole was not sufficiently impaired by the aberrant
mt
gene to prevent these tryptophan precursors from satisfying the nutritional requirement of certain tryptophan auxotrophs. The role of the
mt
gene in determining the permeability of
N. crassa
to amino acids is discussed.
Isolation and Characterization of Ribosomes from
Bacillus subtilis
Spores
Authors: Bishop Helen L. , Doi Roy H.
Published: January 2020

Bishop, Helen L.
(Syracuse University, Syracuse, N.Y.),
and Roy H. Doi
. Isolation and characterization of ribosomes from
Bacillus subtilis
spores. J. Bacteriol.
91:
695–701. 1966.—The isolation of ribosomes from
Bacillus subtilis
spores was accomplished by freezing the spores in liquid nitrogen and grinding the spore pellet with an equal weight of levigated alumina. The ribosomes, which were adsorbed to the alumina, were freed by the addition of vegetative-cell ribosomes or bulk ribonucleic acid (RNA) to the crude alumina-ground extract. The spore ribosomes had sedimentation properties and RNA and protein compositions similar to those of vegetative-cell ribosomes. The difficulty encountered in obtaining spore ribosomes by ordinary extraction methods may be the result of nuclease and protease activities which were demonstrated in spore extracts.
Influence of Blood and Serum on the Antistaphylococcal Activity of Lysostaphin
Authors: Zygmunt Walter A. , Browder Henry P. , Tavormina Peter A.
Published: January 2020

Zygmunt, Walter A.
(Mead Johnson & Co., Evansville, Ind.),
Henry P. Browder, and Peter A. Tavormina
. Influence of blood and serum on the antistaphylococcal activity of lysostaphin. J. Bacteriol.
91:
725–728. 1966.—Human and animal sera, and in certain instances whole blood, exhibited a minimal antagonizing effect on the antistaphylococcal activity of lysostaphin. The presence of 50% human serum only temporarily inhibited cell lysis of viable suspensions of
Staphylococcus aureus
by lysostaphin. The results obtained on the recovery of viable cells after exposure of
S. aureus
to lysostaphin actually suggest an enhancement of the antistaphylococcal activity of the antibiotic in the presence of 50% human serum. The growth-inhibitory activity of the antibiotic against 30 clinical isolates of
S. aureus
was only slightly depressed by the presence of 25% bovine plasma. The data suggest that some binding may occur between the antibiotic and serum proteins, but it is not of an irreversible type. Lysostaphin does not bind readily to red blood cells nor does it enter these cells to any significant degree.
Repair of Radiation-Induced Damage to the Cell Division Mechanism of
Escherichia coli
Authors: Adler Howard I. , Fisher William D. , Hardigree Alice A. , Stapleton George E.
Published: January 2020

Adler, Howard I.
(Oak Ridge National Laboratory, Oak Ridge, Tenn.),
William D. Fisher, Alice A. Hardigree, and George E. Stapleton
. Repair of radiation-induced damage to the cell division mechanism of
Escherichia coli
. J. Bacteriol.
91:
737–742. 1966.—Microscopic observations of irradiated populations of filamentous
Escherichia coli
cells indicated that filaments can be induced to divide by a substance donated by neighboring cells. We have made this observation the basis for a quantitative technique in which filaments are incubated in the presence of nongrowing donor cells. The presence of “donor” organisms promotes division and subsequent colony formation in filaments. “Donor” bacteria do not affect nonfilamentous cells. An extract of “donor” cells retains the division-promoting activity. The extract has been partially fractionated, and consists of a heat-stable and a heat-labile component. The heat-stable component is inactive in promoting cell division, but enhances the activity of the heat-labile component. The division-promoting system is discussed as a radiation repair mechanism and as a normal component of the cell division system in
E. coli
.
Single-Cell-Based Digital PCR Detection and Association of Shiga Toxin-Producing Escherichia coli Serogroups and Major Virulence Genes
Authors: Liu Xuming , Noll Lance , Shi Xiaorong , Porter Elizabeth , Wang Yin , Stoy Colin , Lu Nanyan , Nagaraja T. G. , Anderson Gary , Bai Jianfa
Published: January 2020

Escherichia coli
serogroups O157, O26, O45, O103, O111, O121, and O145, when carrying major virulence genes, the Shiga toxin genes
stx
1
and
stx
2
and the intimin gene
eae
, are important foodborne pathogens. They are referred to as the “top 7” Shiga toxin-producing
E. coli
(STEC) serogroups and were declared by the USDA as adulterants to human health.
Predictors of Clostridioides difficile Infection-Related Complications and Treatment Patterns among Nucleic Acid Amplification Test-Positive/Toxin Enzyme Immunoassay-Negative Patients
Authors: Miller Ryan , Morillas J. A. , Brizendine Kyle D. , Fraser Thomas G.
Published: January 2020

The addition of toxin enzyme immunoassay (EIA) to nucleic acid amplification tests, including PCR, creates challenges in the diagnosis and management of
Clostridioides difficile
infection (CDI). There are limited data in large cohorts, with discordant results, that is, PCR-positive/EIA-negative (PCR
+
/EIA
−
) results. We conducted a retrospective cohort study on all PCR
+
/EIA
−
adult inpatients and assessed CDI-related complications and clinical failure.
Typing of
Nocardia farcinica
by Pulsed-Field Gel Electrophoresis Reveals an Endemic Strain as Source of Hospital Infections
Authors: Blümel J. , Blümel E. , Yassin A. F. , Schmidt-Rotte H. , Schaal K. P.
Published: December 2019

Severe postoperative wound infections caused by
Nocardia farcinica
were repeatedly observed in a German hospital surgical ward. A pulsed-field gel electrophoresis (PFGE) protocol was established to characterize the genetic relatedness of the bacterial isolates from these infections. All 18 isolates from postoperative infections that have occurred since 1985 belong to a common endemic genotype; organisms of this genotype were also detected in the air of two rooms of the department where these postoperative infections occurred. In contrast, two environmental isolates from another building on the same campus showed a distinct genotype. Three cases of pulmonary infections, at a department which is located in proximity to the surgical department, were also caused by the endemic type, which suggests aerogenic spread of the endemic strain to these patients. Controls consisting of epidemiologically unrelated isolates from sporadic infections in other towns belonged in each case to a different genotype. PFGE was well suited to differentiate various types of
N. farcinica
and revealed an endemic strain causing postoperative wound infections possibly after aerogenic transmission.
Determination of Penicillin MICs for
Streptococcus pneumoniae
by Using a Two- or Three-Disk Diffusion Procedure
Authors: Jacobs Michael R. , Bajaksouzian Saralee , Palavecino-Fasola Elizabeth L. , Holoszyc Henry M. , Appelbaum Peter C.
Published: December 2019

The potential for the use of the disk diffusion method to accurately predict penicillin MICs for
Streptococcus pneumoniae
was investigated with penicillin (6 μg), methicillin (5 μg), and oxacillin (1 μg) disks. A total of 183
S. pneumoniae
isolates were tested by three MIC procedures (agar dilution, microdilution, and E-test). Regression analyses of the geometric mean of the three MIC results against (i) the sum of the zone diameters for methicillin, penicillin, and oxacillin disks; (ii) the sum of the zone diameters for methicillin and penicillin disks; and (iii) each of the three individual zone diameters were performed. Calculated MICs were determined from each of these regression analyses and compared to the mean reference MICs. A high level of correlation was obtained with both the two- and the three-disk procedures (
r
= 0.97), with essential agreement rates (±1 doubling dilution) between MICs calculated by the three-disk procedure and the two-disk procedure and the mean reference MICs of 98.4 and 98.9%, respectively. No major or very major errors were obtained with the two- or three-disk procedures. The accuracy of the disks used individually was lower (
r
= 0.84 to 0.93). However, oxacillin and methicillin disk testing remain excellent for screening strains, with all penicillin-susceptible strains having zones of >21 and >22 mm, respectively. The combination disk procedure, which involves the use of three disks (methicillin, oxacillin, and penicillin) or two disks (methicillin and penicillin) for testing
S. pneumoniae
, can provide accurate penicillin MICs and qualitative category results that are comparable to results obtained by the E-test, agar, and microdilution MIC methods.
Enterobacter cloacae
Endophthalmitis: Report of Four Cases
Authors: Okhravi N. , Ficker L. , Matheson M. M. , Lightman S.
Published: December 2019

Members of the genus
Enterobacter
are commensal organisms of the gastrointestinal tract and are considered pathogenic only for patients with lowered resistance to infection (e.g., chronic infection, cancer, or diabetes mellitus) or those with impaired immunity (congenital, acquired, or impaired immunity secondary to therapy). We report on four cases of endophthalmitis caused by
Enterobacter cloacae
: two in patients with acute postoperative endophthalmitis, one in a patient with delayed bleb-related endophthalmitis, and one in a patient presenting with presumed posttraumatic endophthalmitis. Each patient presented with severe disease many days after the onset of ocular symptoms, and two patients had systemic risk factors accounting for a reduced resistance to infection. Endophthalmitis caused by gram-negative bacilli is characterized by acute onset, rapid progression, and poor final visual outcome. Each of these patients was treated by a standard protocol with intravitreal, systemic, and topical antibiotics and systemic steroids. Despite treatment, the final visual outcomes for three of these patients was no perception of light, and that for one patient remained perception of hand movements only. In common with endophthalmitis caused by other gram-negative organisms, intraocular infection secondary to
Enterobacter cloacae
infection is a devastating disease which, despite treatment, results in extensive ocular damage and severe visual loss. Since 1966, only four cases of endophthalmitis secondary to infection with members of this genus have been reported. This report presents four cases which occurred over a period of 14 months and, to the best of our knowledge, the first case of bleb-related endophthalmitis secondary to
E. cloacae
infection.
Clinical Evaluation of the Automated COBAS AMPLICOR MTB Assay for Testing Respiratory and Nonrespiratory Specimens
Authors: Reischl Udo , Lehn Norbert , Wolf Hans , Naumann Ludmila
Published: December 2019

We evaluated the COBAS AMPLICOR PCR system (Roche Diagnostics) for the routine detection of
Mycobacterium tuberculosis
complex (MTBC) in clinical specimens. Diagnostic culture, considered as the reference method, was performed with BACTEC, Löwenstein-Jensen, Stonebrink, and Kirchner media. Occasionally MB-Redox, ESP, or MGIT medium was also used. A total of 643 respiratory and 506 nonrespiratory specimens collected from 807 patients were investigated. Of the 95 culture-positive specimens, 80 were COBAS AMPLICOR MTB positive, and of the 1,054 culture-negative specimens, 1,044 were COBAS AMPLICOR MTB negative. After resolving discrepancies by review of the medical history, the overall sensitivity, specificity, and positive and negative predictive values for the COBAS AMPLICOR MTB assay, respectively, were 83.5, 98.8, 86.7, and 98.6% compared to those of diagnostic culture. In smear-positive specimens, the sensitivity of the COBAS AMPLICOR MTB assay was 96%, versus 48% for smear-negative specimens. No significant differences in the test performance between respiratory and nonrespiratory specimens were observed. The overall inhibition rate was less than 2%, excluding stool specimens. The clear advantages of the COBAS AMPLICOR PCR system are standardized procedures and reagents for specimen processing as well as an internal control for reliable monitoring of PCR inhibitors. By simplifying the work flow through a completely automated amplification and amplicon detection procedure, the COBAS AMPLICOR PCR system proved itself as a very useful component for routine diagnostic procedures.
Comparison of Systems for Identification and Differentiation of Species within the Genus
Yersinia
Authors: Neubauer Heinrich , Sauer Thomas , Becker Heinz , Aleksic Stojanca , Meyer Hermann
Published: December 2019

Of four tested identification systems (API 20E, API Rapid 32 IDE, Micronaut E, and the PCR-based
Yersinia enterocolitica
Amplification Set), API 20E is still the system of choice for identifying pathogenic
Yersinia
isolates. It provides the highest sensitivity both at the genus and at the species level and has the best cost-effectiveness correlation.
Automated RIBA Hepatitis C Virus (HCV) Strip Immunoblot Assay for Reproducible HCV Diagnosis
Authors: Martin P. , Fabrizi F. , Dixit V. , Quan S. , Brezina M. , Kaufman E. , Sra , K. , DiNello R. , Polito A. , Gitnick G.
Published: December 2019

A comparison between the CHIRON RIBA hepatitis C virus (HCV) processor and manual systems was performed by using 88 specimens repeatedly reactive by the second-generation HCV enzyme-linked immunosorbent assay (ELISA) (HCV 2.0 ELISA) and 111 random specimens from volunteer donors. For the second-generation RIBA HCV strip immunoblot assay (SIA) (RIBA HCV 2.0 SIA), test results correlated strongly between the manual and the automated runs (kappa value, 0.937). For the RIBA HCV 3.0 SIA, the correlation of the test results was also high (kappa value, 0.899). Among the specimens with positive results by RIBA HCV 2.0 and 3.0 SIAs, there was a very strong concordance of the test results between the manual and the automated runs with regard to the reactive bands. Nine samples had discordant results between the manual and the automated runs; this was probably attributable to increased variability in antigen scores close to the cutoff values for both tests. Run-to-run and within-run testing by the CHIRON RIBA HCV Processor System showed a very low rate of conflicting values. In conclusion, the CHIRON RIBA HCV Processor System is capable of performing RIBA HCV 2.0 and 3.0 SIAs accurately with minimal operator involvement. In addition, the CHIRON RIBA HCV Processor System shows excellent reproducibility, with the potential for operator-to-operator and site-to-site variability being greatly reduced. Our data indicate that this novel methodology may be very useful for supplemental anti-HCV testing of specimens repeatedly reactive by ELISA in routine clinical assessments and epidemiologic evaluations.
Nosocomial
Candida glabrata
Colonization: an Epidemiologic Study
Authors: Vazquez Jose A. , Dembry Louise M. , Sanchez Veronica , Vazquez Mary A. , Sobel Jack D. , Dmuchowski Carl , Zervos Marcus J.
Published: December 2019

Candida glabrata
has emerged as an important nosocomial pathogen, yet little is known about its epidemiology. We prospectively followed 98 patients admitted to a medical intensive care unit and the bone marrow transplant unit of a university hospital. Samples from environmental surfaces and the hands of hospital personnel were also cultured. Patients with newly acquired
C. glabrata
strains were compared to controls who were culture negative for
C. glabrata. C. glabrata
was recovered from multiple sites from 24 patients and three environmental surfaces. Sixteen patients (17%) acquired
C. glabrata
after admission to the study units. Significant risk factors for the nosocomial acquisition of
C. glabrata
were prolonged duration of hospitalization in the unit and prior antimicrobial use. Strain delineation by restriction enzyme analysis revealed 28 different strains of
C. glabrata
; three strain types were common to nine patients. The environmental isolates were of the same strain type and common to five patients (four patients with newly acquired strains). These results suggest the possibility of exogenous nosocomial acquisition of
C. glabrata
, including the possible acquisition from the hospital environment. Transmission may be by indirect contact since identical strains of
C. glabrata
were recovered from patients who were geographically and temporally associated.
Performance of a PCR Assay for Detection of
Pneumocystis carinii
from Respiratory Specimens
Authors: Caliendo Angela M. , Hewitt Peter L. , Allega Jessica M. , Keen Anne , Ruoff Kathryn L. , Ferraro Mary Jane
Published: December 2019

This study evaluates the performance of a PCR assay for the detection of
Pneumocystis carinii
from respiratory specimens that has been designed for use in the clinical microbiology laboratory. The test includes a simple method for nucleic acid extraction and amplification, a colorimetric probe hybridization technique for detection of amplicons, and an internal control to evaluate for the presence of inhibitors of amplification. Two hundred thirty-two clinical specimens (120 induced-sputum [IS] and 112 bronchoalveolar lavage [BAL] specimens) from 168 patients were tested by both immunofluorescent (direct fluorescent-antibody [DFA]) staining and PCR. Of the 112 BAL specimens, 17 were positive for
P. carinii
by DFA staining and PCR. An additional two specimens were DFA negative and PCR positive. For BAL specimens, the sensitivity and specificity of PCR compared to DFA were 100 and 98%, respectively. Eighteen IS specimens were positive for
P. carinii
by DFA, and 27 were positive by PCR. One of the 18 DFA-positive IS specimens was negative by PCR; this patient had just completed therapy for
P. carinii
pneumonia. Of the 10 specimens that were PCR positive and DFA negative, 4 were from patients who had a subsequent BAL specimen that was positive by DFA and PCR. For IS specimens, the sensitivity of DFA and PCR was 82 and 95%, respectively. The specificity of PCR for IS specimens was 94%. Due to the high sensitivity of PCR for the detection of
P. carinii
from IS specimens, a PCR-based diagnostic test may be a useful screening test and may alleviate the need for bronchoscopy in some patients.
Rapid Screening Tests for Determining In Vitro Susceptibility of Herpes Simplex Virus Clinical Isolates
Authors: de la Iglesia Pedro , Melón Santiago , López Beatriz , Rodriguez Mercedes , Blanco Maria I. , Mellado Purificación , de Oña Maria
Published: December 2019

The susceptibility of human herpes simplex virus (HSV) to acyclovir (ACV) was determined with the use of a single dose of the drug (1 and 2 μg of ACV per ml for HSV-1 and HSV-2, respectively) in two rapid assays: a rapid cytopathic effect inhibitory assay (Rapid CIA) and a rapid dye uptake assay (Rapid DUA). These tests allow the simultaneous determination of virus titer and susceptibility to ACV at a determined viral concentration (100 50% tissue culture infective doses and 100 50% dye uptake units). These tests were compared with a conventional susceptibility assay (dye uptake assay) and showed similar results. Indeterminate results with the Rapid CIA appeared in 3 of 30 samples. With the use of both Rapid CIA and Rapid DUA, we were able to determine the susceptibility of 100% of the isolates. The rapid tests, unlike conventional assays, are able to provide susceptibility results within 3 days after the virus has been isolated from a clinical specimen and could thus play a direct role in therapeutic decisions.
Can Results Obtained with Commercially Available MicroScan Microdilution Panels Serve as an Indicator of β-Lactamase Production among
Escherichia coli
and
Klebsiella
Isolates with Hidden Resistance to ExpandedSpectrum Cephalosporins and Aztreonam?
Authors: Moland Ellen Smith , Sanders Christine C. , Thomson Kenneth S.
Published: December 2019

Among clinical isolates of
Escherichia coli
,
Klebsiella pneumoniae
, and
Klebsiella oxytoca
, there is an ever-increasing prevalence of β-lactamases that may confer resistance to newer β-lactam antibiotics that is not detectable by conventional procedures. Therefore, 75 isolates of these species producing well-characterized β-lactamases were studied using two MicroScan conventional microdilution panels, Gram Negative Urine MIC 7 (NU7) and Gram Negative MIC Plus 2 (N+2), to determine if results could be utilized to provide an accurate indication of β-lactamase production in the absence of frank resistance to expanded-spectrum cephalosporins and aztreonam. The enzymes studied included Bush groups 1 (AmpC), 2b (TEM-1, TEM-2, and SHV-1), 2be (extended spectrum β-lactamases [ESBLs] and K1), and 2br, alone and in various combinations. In tests with
E. coli
and
K. pneumoniae
and the NU7 panel, cefpodoxime MICs of ≥2 μg/ml were obtained only for isolates producing ESBLs or AmpC β-lactamases. Cefoxitin MICs of >16 μg/ml were obtained for all strains producing AmpC β-lactamase and only 1 of 33 strains producing ESBLs. For the N+2 panel, ceftazidime MICs of ≥4 μg/ml correctly identified 90% of ESBL producers and 100% of AmpC producers among isolates of
E. coli
and
K. pneumoniae
. Cefotetan MICs of ≥ 8 μg/ml were obtained for seven of eight producers of AmpC β-lactamase and no ESBL producers. For tests performed with either panel and isolates of
K. oxytoca
, MICs of ceftazidime, cefotaxime, and ceftizoxime were elevated for strains producing ESBLs, while ceftriaxone and aztreonam MICs separated low-level K1 from high-level K1 producers within this species. These results suggest that microdilution panels can be used by clinical laboratories as an indicator of certain β-lactamases that may produce hidden but clinically significant resistance among isolates of
E. coli
,
K. pneumoniae
, and
K. oxytoca
. Although it may not always be possible to differentiate between strains that produce ESBLs and those that produce AmpC, this differentiation is not critical since therapeutic options for patients infected with such organisms are similarly limited.
Development of Specific Nested Oligonucleotide PCR Primers for the
Streptococcus iniae
16S-23S Ribosomal DNA Intergenic Spacer
Authors: Berridge Brian R. , Fuller Jeffrey D. , de Azavedo Joyce , Low Donald E. , Bercovier Herve , Frelier Paul F.
Published: December 2019

Streptococcus iniae
is a cause of septicemia, meningoencephalitis, and death in farmed fish and of cellulitis in human beings. A set of nested oligonucleotide PCR primers that specifically amplified a 373-bp subunit from a variety of clinical isolates from farmed fish and human patients were constructed from a 524-bp consensus sequence of the
S. iniae
16S-23S ribosomal DNA intergenic spacer.
Follow-Up of
Staphylococcus aureus
Nasal Carriage after 8 Years: Redefining the Persistent Carrier State
Authors: VandenBergh Marjolein F. Q. , Yzerman Ed P. F. , van Belkum Alex , Boelens Hélène A. M. , Sijmons Marly , Verbrugh Henri A.
Published: December 2019

Studies of
Staphylococcus aureus
nasal carriage have distinguished three carriage patterns: persistent, intermittent, and noncarriage. The criteria used to identify these carriage patterns have been inconsistent. In 1988 the
S. aureus
nasal carrier index, i.e., the proportion of nasal swab specimen cultures yielding
S. aureus
, was determined for 91 staff members of various departments of a large university hospital by obtaining weekly nasal swab specimens for culture over a 12-week period. Thirty-three (36%) persons had carrier indices of 0.80 or higher, 15 (17%) had indices between 0.1 and 0.7, and 43 (47%) had indices of zero. In 1995, 17 individuals with carrier indices of 0.80 or higher in 1988 were available for reexamination. For 12 (71%) of these individuals,
S. aureus
was again isolated from a single nasal swab, i.e., from each individual with a 1988 carrier index of 1.0 but from only half of those with indices below 1.0. Genotyping (by randomly amplified polymorphic DNA analysis and pulsed-field gel electrophoresis) of all
S. aureus
strains showed that strains isolated from only three individuals, all with 1988 carrier indices of 1.0, in 1988 and 1995 showed genetic similarity. In conclusion, persistent
S. aureus
nasal carriage is a unique characteristic of a fraction of the population, and the attribute “persistent” should be confined to those individuals for whom serial nasal swab specimen cultures consistently yield
S. aureus
.
Amplified-Fragment Length Polymorphism Fingerprinting of
Mycoplasma
Species
Authors: Kokotovic Branko , Friis Niels F. , Jensen Jørgen S. , Ahrens Peter
Published: December 2019

Amplified-fragment length polymorphism (AFLP) is a whole-genome fingerprinting method based on selective amplification of restriction fragments. The potential of the method for the characterization of mycoplasmas was investigated in a total of 50 strains of human and animal origin, including
Mycoplasma genitalium
(
n
= 11),
Mycoplasma pneumoniae
(
n
= 5),
Mycoplasma hominis
(
n
= 5),
Mycoplasma hyopneumoniae
(
n
= 9),
Myco plasma flocculare
(
n
= 5),
Mycoplasma hyosynoviae
(
n
= 10), and
Mycoplasma dispar
(
n
= 5). AFLP templates were prepared by the digestion of mycoplasmal DNA with
Bgl
II and
Mfe
I restriction endonucleases and subsequent ligation of corresponding site-specific adapters. The amplification of AFLP templates with a single set of nonselective primers resulted in reproducible fingerprints of approximately 60 to 80 fragments in the size range of 50 to 500 bp. The method was able to discriminate the analyzed strains at species and intraspecies levels as well. Each of the tested
Mycoplasma
species developed a banding pattern entirely different from those obtained from other species under analysis. Subtle intraspecies genomic differences were detected among strains of all of the
Mycoplasma
species analyzed. The extent of polymorphism varied markedly between the analyzed mycoplasmas, comprising pattern similarity levels from 61.7% detected among
M. dispar
strains to 95.9% detected among
M. genitalium
strains. The results of the present study provide evidence of the high discriminatory power of AFLP analysis, suggesting the possible applicability of this method to the molecular characterization of mycoplasmas.
Natural History of Intestinal Microsporidiosis among Patients Infected with Human Immunodeficiency Virus
Authors: Dascomb Kristin , Clark Rebecca , Aberg Judith , Pulvirenti Joseph , Hewitt Ross G. , Kissinger Patricia , Didier Elizabeth S.
Published: December 2019

A chart review of 73 human immunodeficiency virus (HIV)-infected patients with enteric microsporidiosis was conducted to define the natural history of microsporidiosis. A substantial proportion of patients remained symptomatic after 6 months (54.8% with persistent diarrhea and 51.2% with weight loss). Predictors for persistent diarrhea included high HIV RNA viral load and no initiation of protease inhibitor therapy.
Serodiagnosis of Human Granulocytic Ehrlichiosis by a Recombinant HGE-44-Based Enzyme-Linked Immunosorbent Assay
Authors: Ijdo Jacob W. , Wu Caiyun , Magnarelli Louis A. , Fikrig Erol
Published: December 2019

Current antibody testing for human granulocytic ehrlichiosis relies predominantly on indirect fluorescent-antibody assays and immunoblot analysis. Shortcomings of these techniques include high cost and variability of test results associated with the use of different strains of antigens derived from either horses or cultured HL-60 cells. We used recombinant protein HGE-44, expressed and purified as a maltose-binding protein (MBP) fusion peptide, as an antigen in a polyvalent enzyme-linked immunosorbent assay (ELISA). Fifty-five normal serum samples from healthy humans served as a reference to establish cutoff levels. Thirty-three of 38 HGE patient serum samples (87%), previously confirmed by positive whole-cell immunoblotting, reacted positively in the recombinant ELISA. In specificity analyses, serum samples from patients with Lyme disease, syphilis, rheumatoid arthritis, and human monocytic ehrlichiosis (HME) did not react with HGE-44–MBP antigen, except for one sample (specificity, 98%). We conclude that recombinant HGE-44 antigen is a suitable antigen in an ELISA for the laboratory diagnosis and epidemiological study of HGE.
Novel Bacterium Isolated from a Lung Transplant Patient with Cystic Fibrosis
Authors: Pitulle Christian , Citron Diane M. , Bochner Barry , Barbers Richard , Appleman Maria D.
Published: December 2019

The major clinical problem for patients with cystic fibrosis (CF) is progressive loss of pulmonary function, usually due to chronic bacterial infections. A patient with CF and a lung transplant was severely infected with a previously unidentified gram-negative bacterium. We isolated this organism (strain DS15158) from the patient and characterized it by phylogenetic analysis of the small-subunit rRNA and biochemically by the BIOLOG GN MicroPlate assay, fatty acid analysis, and various standard laboratory tests. No close match to any other organism could be found. Isolate DS15158 represents a new genus-level divergence within the bacterial subdivision α-Proteobacteriaon the basis of the 16S rRNA gene analysis.
Multiplex Reverse Transcriptase PCR Assay for Simultaneous Detection of Three Fish Viruses
Authors: Williams K. , Blake S. , Sweeney A. , Singer J. T. , Nicholson B. L.
Published: December 2019

A multiplex reverse transcriptase (RT)-PCR assay was developed for the simultaneous detection of three different fish viruses: infectious pancreatic necrosis virus (IPNV), infectious hematopoietic necrosis virus (IHNV), and viral hemorrhagic septicemia virus (VHSV). The sensitivity levels of the multiplex RT-PCR assay were 100, 1, and 32 50% tissue culture infective doses/ml for IPNV, IHNV, and VHSV, respectively.
Posttreatment Follow-Up of Brucellosis by PCR Assay
Authors: Morata Pilar , Queipo-Ortuño María Isabel , Reguera JoséMaría , García-Ordoñez Miguel Angel , Pichardo Cristina , Colmenero Juan de Dios
Published: December 2019

In order to evaluate the usefulness of a peripheral blood PCR assay in the posttreatment follow-up of brucellosis, a cohort of 30 patients was studied by means of blood cultures, rose Bengal, seroagglutination, Coombs' antibrucella tests, and PCR assay at the time of diagnosis, at the end of treatment, and 2, 4, and 6 months later. Of the 29 patients whose PCR assays were initially positive, 28 (96.5%) were negative at the conclusion of the treatment. PCR was positive for the two patients who had relapses and negative for another four who had suspected but unconfirmed relapses. PCR was negative for 98.3% of the follow-up samples from those patients who had a favorable evolution. In conclusion, PCR appears to be a very useful technique, not only for the initial diagnosis of the disease, but also for posttreatment follow-up and the early detection of relapses.
Evaluation of AMPLICOR
Neisseria gonorrhoeae
PCR Using
cppB
Nested PCR and 16S rRNA PCR
Authors: Farrell David J.
Published: December 2019

Certain strains of
Neisseria subflava
and
Neisseria cinerea
are known to produce false-positive results with the AMPLICOR
Neisseria gonorrhoeae
PCR (Roche Diagnostic Systems, Branchburg, N.J.). The analytical sensitivity and analytical specificity of three PCR tests were assessed with 3 geographically diverse
N. gonorrhoeae
strains and 30 non-
N. gonorrhoeae Neisseria
spp. The sensitivities of the in-house nested
cppB
gene and the 16S rRNA PCR methods were greater than that of the AMPLICOR
N. gonorrhoeae
PCR with purified DNA from all 3
N. gonorrhoeae
strains. Six of 14 clinical strains of
N. subflava
(1 from a vaginal swab, 5 from respiratory sites) produced false-positive AMPLICOR
N. gonorrhoeae
PCR results and were negative by the two other PCR methods. When applied to 207 clinical specimens selected from a population with a high prevalence (∼9%) of infection, the results for 15 of 96 (15.6%) AMPLICOR-positive specimens and 14 of 17 (82.3%) AMPLICOR-equivocal specimens were not confirmed by the more sensitive nested
cppB
PCR method. Only 2 of 94 (2.1%) of AMPLICOR
N. gonorrhoeae
PCR-negative specimens from the same population tested positive by the nested
cppB
method. These results suggest that for this population the AMPLICOR
N. gonorrhoeae
PCR test is suitable as a screening test only and all positive results should be confirmed by a PCR method that is more specific and at least as sensitive. This study also illustrates that caution should be used when introducing commercially available nucleic acid amplification-based diagnostic tests into the regimens of tests used for populations not previously tested with these products.
The IS
6110
Restriction Fragment Length Polymorphism in Particular Multidrug-Resistant
Mycobacterium tuberculosis
Strains May Evolve Too Fast for Reliable Use in Outbreak Investigation
Authors: Alito Alicia , Morcillo Nora , Scipioni Silvia , Dolmann Alberto , Romano María I. , Cataldi Angel , van Soolingen Dick
Published: December 2019

To study possible nosocomial transmission of multidrug-resistant (MDR)
Mycobacterium tuberculosis
, strain types and other information on 24, mostly human immunodeficiency virus-positive patients, were collected. Isolates from 11 patients had identical IS
6110
restriction fragment length polymorphism (RFLP) patterns as well as spoligotype patterns and resistance profiles. Noticeably, nine other isolates from related cases also exhibited identical spoligotypes but slightly different RFLP patterns. These results indicate that for some MDR strains, the evolutionary clock of IS
6110
RFLP may run too fast for reliable interpretation of strain typing results over a period of a few years.
Unexpected Cross-Reaction with
Fusobacterium necrophorum
in a PCR for Detection of Mycoplasmas
Authors: Jensen Jørgen Skov , Bruun Brita , Gahrn-Hansen Bente
Published: December 2019

Cross-reactions with
Fusobacterium necrophorum
were found in a PCR designed for detection of a wide range of mycoplasma species. Twenty-five strains of
Fusobacterium
were examined; all 14
F. necrophorum
strains reacted positively, whereas all 7
Fusobacterium nucleatum
strains reacted negatively. Two strains that were not
F. necrophorum
yielded variable results.
Detection of Enzootic Babesiosis in Baboons (Papio cynocephalus) and Phylogenetic Evidence Supporting Synonymy of the GeneraEntopolypoidesandBabesia
Authors: Bronsdon Melinda A. , Homer Mary J. , Magera Jennifer M. H. , Harrison Carol , Andrews Robert G. , Bielitzki Joseph T. , Emerson Carol L. , Persing David H. , Fritsche Thomas R.
Published: December 2019

Blood smear evaluation of two baboons (Papio cynocephalus) experiencing acute hemolytic crises following experimental stem cell transplantation revealed numerous intraerythrocytic organisms typical of the genusBabesia. Both animals had received whole-blood transfusions from two baboon donors, one of which was subsequently found to display rare trophozoites ofEntopolypoides macaci. An investigation was then undertaken to determine the prevalence of hematozoa in baboons held in our primate colony and to determine the relationship, if any, between the involved species. Analysis of thick and thin blood films from 65 healthy baboons (23 originating from our breeding facility, 26 originating from an out-of-state breeding facility, and 16 imported from Africa) for hematozoa revealed rareE. macaciparasites in 31%, with respective prevalences of 39, 35, and 12%. Phylogenetic analysis of nuclear small-subunit rRNA gene sequences amplified from peripheral blood of a baboon chronically infected withE. macacidemonstrated this parasite to be most closely related toBabesia microti(97.9% sequence similarity); sera from infected animals did not react in indirect fluorescent-antibody tests withBabesia microtiantigen, however, suggesting that they represent different species. These results support an emerging view that the genusEntopolypoidesMayer 1933 is synonymous with that of the genusBabesiaStarcovici 1893 and that the morphological variation noted among intracellular forms is a function of alteration in host immune status. The presence of an underrecognized, but highly enzootic,Babesiasp. in baboons may result in substantial, unanticipated impact on research programs. The similarity of this parasite to the known human pathogenB. microtimay also pose risks to humans undergoing xenotransplantation, mandating effective screening of donor animals.
Septic Shock Due to
Helicobacter fennelliae
in a Non-Human Immunodeficiency Virus-Infected Heterosexual Patient
Authors: Hsueh Po-Ren , Teng Lee-Jene , Hung Chien-Chin , Chen Yu-Chi , Yang Pan-Chyr , Ho Shen-Wu , Luh Kwen-Tay
Published: December 2019

Helicobacter fennelliae
(formerly
Campylobacter fennelliae
) has been reported to cause bacteremia in homosexual men with or without human immunodeficiency virus (HIV) infection. We report here a 48-year-old, non-HIV-infected, heterosexual man with diabetes mellitus and cirrhosis of the liver who developed bacteremia and septic shock due to
H. fennelliae
. The patient was treated successfully initially with intravenous ampicillin-sulbactam and ceftazidime, followed by ampicillin-sulbactam only. These agents were active in vitro against the isolate by E-test results. To our knowledge, this is the first documented case of septic shock due to
H. fennelliae
in a non-HIV-infected, heterosexual, immunocompromised patient.
Amplification of a 500-Base-Pair Fragment from Cultured Isolates of
Mycobacterium bovis
Authors: Rodríguez Juan Germán , Fissanoti Juan Carlos , Del Portillo Patricia , Patarroyo Manuel Elkin , Romano María Isabel , Cataldi Angel
Published: December 2019

The presence of a 500-bp fragment which amplifies a region from the genome of
Mycobacterium bovis
(J. G. Rodriguez, G. A. Meija, P. Del Portillo, M. E. Patarroyo, and L. A. Murillo, Microbiology 141:2131–2138, 1995) was evaluated by carrying out PCR on 121
M. bovis
isolates. The
M. bovis
strains, previously characterized by culture and biochemical tests, were isolated from cattle in different regions of Argentina, Mexico, and Colombia. Four additional strains isolated from sea lions that belong to the
M. tuberculosis
complex were also included in the study. All of the isolates tested were PCR positive, rendering the expected 500-bp band and giving a correlation of 100% with previous microbiological characterization. Southern blot analysis revealed a common band of 1,800 bp and a polymorphic high-molecular-mass hybridization pattern. The results show that this assay may be useful for diagnosis and identification of
M. bovis
in cattle.
Comparison of Molecular Methods for Typing
Vibrio parahaemolyticus
Authors: Marshall S. , Clark C. G. , Wang G. , Mulvey M. , Kelly M. T. , Johnson W. M.
Published: December 2019

An outbreak of
Vibrio parahaemolyticus
gastroenteritis on Canada’s west coast in 1997 emphasized the need to develop molecular methods for differentiation and typing of these organisms. Isolates were analyzed by enterobacterial repetitive intergenic consensus sequence (ERIC) PCR, detection of restriction fragment length polymorphisms (RFLP) in rRNA genes (ribotyping), pulsed-field gel electrophoresis (PFGE), and RFLP analysis of the genetic locus encoding the polar flagellum (Fla locus RFLP analysis). ERIC PCR and ribotyping were the most informative typing methods, especially when used together, while Fla locus RFLP analysis was the least discriminatory. PFGE exhibited good discrimination but suffered from a high incidence of DNA degradation. ERIC PCR and ribotyping will be useful for the evaluation of genetic and epidemiological relationships among
V. parahaemolyticus
strains.