Chlamydia Trachomatis Testing: An Example of Evolving
Technology
by Harvey George, Ph.D., FACB, DABCC
Massachusetts Department of Public Health, State Laboratory
Institute
Chlamydia trachomatis is a nonmotile, gram-negative, obligate intracellular
bacterium that is almost exclusively a human pathogen. It is the most
common sexually transmitted genital infection. It is manifested in
males primarily as urethritis and in females as a cervicitis. A swab
of the intraurethral or endocervical canals is collected to detect
and identify an infection with the organism.
Isolation and identification of the agent initially was done in cell
culture with cycloheximide-treated McCoy or other appropriate cells,
followed by the use of fluorescein-conjugated monoclonal antibodies
to demonstrate the C. trachomatis inclusion in the cell culture. Although
this method was used as the "gold standard", having a specificity
of 100%, its sensitivity was highly technique dependent, varying from
50 to 75%. In addition, cell culture required skills and equipment
not commonly found in bacteriology laboratories.
Subsequently, antigen detection enzyme immunoassay (EIA) test methods
were developed commercially. These tests possessed the advantage of
speed and ease of use, but were not as sensitive and specific as cell
culture. The sensitivities of the commercial kits varied from 70 to
almost 100% as compared to cell culture. It should be noted however,
that all of these EIA methods are considered by CLIA to be screening
tests and hence need to be confirmed by another more definitive test.
Recognition of the need to improve both sensitivity and specificity
of disease detection resulted in the development of nucleic acid probes
for chlamydial RNA and systems for the amplification of chlamydial
DNA. Available data suggests that the sensitivity of nucleic probes
is comparable to the better antigen detection kits and cell culture
methods, while possessing improved specificity over the EIA methods.
On the other hand, the sensitivity of amplification tests is greater
than either the EIA or the cell culture methods, and theoretically
should approach 100%. In practice, the sensitivity probably never
reaches 100% because of sampling problems, when very low numbers of
chlamydial particles are present, and when there is inhibition of
the amplification reactions by factors in the clinical specimens.
The number of nucleic acid amplification methods licensed for the
detection of C. trachomatis in clinical specimens is increasing. At
the present time three are in general use: ligase chain reaction (LCR),
polymerase chain reaction (PCR) and transcription-mediated amplification
(TMA). These assays can be used with first-voided urine samples as
well as urethral and endocervical swab specimens. The ability to use
urine specimens provides a major advantage to the amplification tests,
because invasive collection methods are not required and specimens
can be collected in settings other than traditional clinical or physician
office settings.
Unfortunately, the cost of performing an amplification test is much
greater than that of an EIA, so some labs have taken an indirect approach
to improving their sensitivity and keeping their expense down. These
labs are screening all specimens with an EIA test and then re-analyzing
all "high" negative specimens with an amplification test, a less than
ideal compromise.
Following our laboratory's conversion from EIA technology to nucleic
acid amplification technology (LCR), we observed a two-fold increase
in positivity rate from similar populations. Therefore, the State
Laboratory tests all specimens, both urine and swab, directly by nucleic
acid amplification to assure optimal sensitivity.
One problem, common to all nucleic amplification procedures, is the
inability to distinguish between active infection and residual nucleic
acid that may be remaining from ruptured cells after successful treatment.
This renders the practice of "test of cure" testing impractical in
most clinical settings. However, the ability to extend screening services
to such underserved populations as juveniles, for whom invasive sample
collection would be inappropriate, or prisoners where screening STD
examinations would be financially prohibitive, more than compensates
for this apparent shortcoming.
Adherence
to Screening Criteria Project
Development of a
Mechanism to Verify and Measure Adherence to Chlamydia Screening
Criteria in Family Planning Clinics in Three New England States.
J Day1, F
Cohen2, H Jenkins3, E Kieltyka4, M
Proulx5, M Ritson6, B Woods7
1 John Snow, Inc.
(JSI), Boston, MA; 2 Planned Parenthood of
Northern New England, Williston, VT; 3Connecticut
Department of Public Health, STD Control Program, Hartford, CT; 4
Family Planning Association of Maine, Augusta, ME; 5
Vermont Department of Public Health, STD Program, Burlington, VT; 6
Planned Parenthood of Connecticut, New Haven, CT; 7 Maine
Department of Public Health, HIV/STD Program, Augusta, ME.
Background: The Title
X Family Planning (FP) and STD Programs of Connecticut, Maine and
Vermont and JSI received a CDC Infertility Prevention Project
Innovation Award to evaluate adherence to chlamydia screening
criteria. The states participate in the Region I Chlamydia project
and selectively screen all women < 25 years old for chlamydia.
Objectives: 1) To
develop a data collection tool to measure adherence to regional
chlamydia screening criteria; 2) to conduct a pilot study to test
the tool via medical record review.
Methods: A data
collection tool was developed to collect age, risk factors
satisfying the regional screening criteria, chlamydia test results,
and reasons for not screening. Medical records were randomly
selected from clinic-specific lists of women undergoing pelvic
exams. The tool was piloted in 6 FP clinics and 25 medical records
per clinic were audited.
Results: Of the 72/112
(64%) women who met the regional screening criteria, 30/72 (42%)
were not tested for chlamydia. The most frequent reasons for not
testing included no recent change in sex partner (n=12) and refusing
testing (n=10). The pilot study has been expanded to audit medical
records 33 FP clinics. The results of this audit, documenting the
percent of women meeting the screening criteria, chlamydia test
results and reasons for not screening, will be presented.
Conclusions: The
pilot study revealed valid reasons why women were not screened for
chlamydia. Studies conducted to measure adherence to screening
criteria should include documentation of reasons why screening did
not occur.
Implications for
Programs/Policy: Future mechanisms developed to measure
adherence to screening criteria should include documentation of
reasons why women are not screened. Regional screening criteria may
need to be reevaluated.
Implications for Research:
More studies are needed to document reasons why women are not
screened for chlamydia and to determine how best to capture such
information.
Learning Objectives:
Participants will be able to identify key questions that should be
asked in data collection tools used to measure adherence to
chlamydia screening criteria and will be able describe reasons why
women are not screened.
Jail
STD/TB Prevalence Monitoring Project
The objectives of the Centers for Disease Control and Prevention,
Jail STD/TB Prevalence Monitoring Project are to: 1) increase
collaboration between the Infertility Prevention Project (IPP) and
the Jail Prevalence Sites; 2) reduce duplication of effort by
allowing projects to transmit data to one centralized facility, and;
3) facilitate the expansion of prevalence monitoring activities to
additional jail and juvenile sites.
In Region I, Massachusetts was funded in 2000 to collect prevalence
data for syphilis, chlamydia, gonorrhea, HIV and tuberculosis among
arrestees at the Hampden County Jail. The project hopes to
expand to Rhode Island by collecting prevalence data for syphilis,
chlamydia, gonorrhea, HIV and tuberculosis from the Cranston County
Jail.
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Laboratory, Family Planning and STD Contact Information
Connecticut - CT
Family Planning
Planned Parenthood of Connecticut
345 Whitney Avenue
New Haven, CT 06511
Phone: (203) 752-2843
Fax: (203) 752-3258
STD
Department of Public Health
STD Control Program
410 Capitol Avenue
MS #11 STD
PO Box 340308
Hartford, CT 06134-0308
Phone: (860) 509-7920
Fax: (860) 509-7275
Laboratory
CT Dept. of Public Health Lab
10 Clinton St.
Hartford, CT 06106
Phone: (860) 509-8577
Fax: (860) 509-8619
Maine - ME
Family Planning
Family Planning Association of Maine
PO Box 587
Augusta, ME 04332-0587
Phone: (207) 622-7524
Fax: (207) 622-0836
www.fpam.org
STD
HIV/STD Program
286 Water St., 9th Floor
State House Station 11
Augusta, ME 04333
Phone: (207) 287-3747 (5199vm)
Fax: (207) 287-6865
Laboratory
Health and Environmental Testing Lab
221 State Street, Station 12
Augusta, ME 04333
Phone: (207) 287-2727
Fax: (207) 287-6835
Massachusetts - MA
Family Planning
Boston Family Planning
178 Tremont Street
Boston, MA 02111
Phone: (617) 357-6000
www.bostonabcd.org/familyplanning/index.htm
Health Quarters
19 Broadway
Beverly, MA 01915
Phone: (978) 927-9824
Fax: (978) 922-5904
www.healthq.org
Tapestry Health Systems
320 Riverside Drive
Florence, MA 01062
Phone: (413) 586-2016
Fax: (413) 586-0212
Health Awareness of Central MA
405 Grove Street
Worcester, MA 01605
Phone: (508) 756-7123
Fax: (508) 756-8922
Health Care of South Eastern MA
942 W. Chestnut Street
Brockton, MA 02301
Phone: (508) 427-1603 x241
Fax: (508) 427-1602
STD
Division of STD Prevention
Department of Public Health
305 South Street
Boston, MA 02130-3597
Phone: (617) 983-6940 or 6941 (voice mail)
Fax: (617) 983-6618
Laboratory
State Department of Health State Labs
305 South Street
Boston, MA 02130-3597
Phone: (617) 983-6950
Fax: (617) 983-6618
New Hampshire - NH
Family Planning
Family Planning Program
29 Hazen Drive
Concord, NH 03301-6504
Phone: (603) 271-4527
Fax: (603) 271-3827
STD
STD/HIV Prevention Bureau
NH Department of Health
29 Hazen Drive
Concord, NH 03301-6527
Phone: (603) 271-5457
Fax: (603) 271-4934
Laboratory
Public Health Laboratories
Office of Community and Public Health
29 Hazen Drive
Concord, NH 03301-6527
Phone: (603) 271-2764
Fax: (603) 271-4783
Rhode Island - RI
Family Planning
Rhode Island Department of Health/ Division of Family Health
3 Capitol Hill, Room 302
Providence, RI 02908
Phone: (401) 222-5936
Fax: (401) 222-1442
STD
RI DPH
3 Capitol Hill, Rm. 106
Providence, RI 02908
Phone: (401) 222-3283
Fax: (401) 222-2488
Laboratory
State Department of Health
Health Lab Building
50 Orms Street
Providence, RI 02904
Phone: (401) 222-5600 page / 222-5596 vm
Fax: (401) 222-6985
Vermont - VT
Family Planning
Planned Parenthood of Northern NE
183 Talcott Road, Suite 101
Williston, VT 05495
Phone: (802) 878-7716
Fax: (802) 878-8001
www.ppnne.org
STD
VT DH/STD
108 Cherry Street, PO Box 70
Burlington, VT 05402
Phone: (802) 863-7245 or 888-3378
Fax: (802) 863-7314
Laboratory
VT DPH Lab
195 Colchester Avenue, POB 1125
Burlington, VT 05402-1125
Phone: (802) 863-7629
Fax: (802) 863-7632
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