Comparison of four nonculture diagnostic tests for Chlamydia trachomatis infection

OBJECTIVE

Chlamydia trachomatis (CT) is one of the commonest sexually transmitted diseases leading to urethritis, epididymitis, prostatitis in men and urethritis, cervicitis, endometritis and pelvic inflammatory disease, sometimes complicated by infertility and ectopic gestation in women. Since culture of fastidious bacteria in a monocellular medium is not available in most laboratories we compared direct immunofluorescence antigen detecting test (DFA) with three other nonculture tests-antigen detecting enzyme immunoassay (EIA), Papanicolaou staining (Pap) and Geimsa stain for endocervical swabs from women in reproductive age group.

METHODS

Three hundred and fifty seven women between 16 and 41 years of age and attending family welfare clinics of IRR were evaluated for the presence pap smears. In 100 cases DFA staining was compared with Geimsa staining.

RESULTS

DFA test was positive in 60/357 (16.8%), EIA in 29 (8.1%) of cases and Pap smear in 37 (10%) cases. In the second group DFA was positive in 17 (17%) and Geimsa in 10 (10%) cases.

CONCLUSION

Amongst the four tests DFA showed maximum sensitivity. ELISA is less expensive but has lower sensitivity. Pap stain also has less sensitivity and good specificity, the quality of smear is likely to affect the diagnosis. Though Geimsa stain is cheapest, for chlamydial cervicitis in our experience it was not as sensitive as DFA. Thus each laboratory must decide the method depending on its resources.

Patterns of Chlamydia trachomatis testing and follow-up at a University Hospital Medical Center

OBJECTIVE

Although testing for Chlamydia trachomatis is encouraged and increasingly practiced at sexually transmitted disease (STD) and family planning clinics, patterns of testing and follow-up in other settings are not well described. To begin to address these issues, we performed a chart review of patients with a positive laboratory test for C. trachomatis at a major university medical center.

METHODS

Chart review of medical records for all patients with positive laboratory tests for C. trachomatis during calendar year 1996.

RESULTS

Of 326 patients with positive tests, 95% were female and 5% were male. Median age was 22 for females and 25 for males. Most positive C. trachomatis test results were from the emergency room (ER)/walk-in clinic (55%) or patients receiving obstetric/gynecologic (OB/GYN) care (31%). While most C. trachomatis tests performed were on patients who had symptoms, patterns of treatment varied between sites. Fifty-seven percent of ER/walk-in patients received empiric antibiotics at the initial visit versus 36% of patients under OB/GYN care. Among patients with positive screening tests seen in the ER/walk-in clinic, 32% of patients had no treatment documented versus 14% of OB/GYN patients. Four percent of women with positive tests who did not receive therapy at the time of their initial evaluation developed pelvic inflammatory disease in the interval between testing and return to the medical center.

CONCLUSIONS

Of the patients with positive chlamydial screening tests, the proportion not treated was similar to that found in studies performed in STD clinics.

Detection of viral and bacterial infections in women with normal and abnormal colposcopy

Signs and symptoms of sexually-transmitted diseases (STD) do not allow any etiological diagnosis in women. Colposcopic findings are seldom pathognomic. Consequently, the microbiology laboratory with the recent availability of molecular diagnostic tools is required to detect the infectious bacterial and/or viral agents involved in STD. In cervical samples of women submitted to gynaecological screening for past or present signs and symptoms of inflammation and with different colposcopic findings, we searched by molecular approaches Chlamydia trachomatis, Mycoplasma genitalium, herpes simplex virus type 1 and 2, adenovirus and 45 genotypes of papillomaviruses and, by cultural methods Mycoplasma hominis and Ureaplasma urealyticum. Colposcopy permitted us to divide the studied population into three groups: 48 women had negative colposcopic findings, 50 presented signs of flogosis and 100 resulted positive for an abnormal transformation zone (ANTZ) and/or for HPV colposcopic findings. Results obtained by microbiological assays indicated that the prevalence of infectious agents did not always correlate with colposcopy. Double and triple infections were found in groups 2 and 3, with mycoplasmas being the most common microrganisms present in association and quite almost copresent with papillomaviruses.

Evidence-based guidelines for the management of genital chlamydial infection in general practice. (Leicestershire Chlamydia Guidelines Group)

BACKGROUND

Valid clinical guidelines can be effective in improving patient care. Genital Chlamydia trachomatis infection is the commonest curable sexually transmitted disease (STD) in England and Wales and is an important cause of pelvic inflammatory disease (PID), tubal infertility and ectopic pregnancy. No published guidelines exist on managing genital chlamydial infection in British general practice.

OBJECTIVE

We aimed to develop valid guidelines for the management of genital chlamydial infection for use in British general practice.

METHODS

A district-wide postal questionnaire survey was used to document current clinical practice. A critical review of the evidence concerning the management of genital chlamydial infection as it relates to British general practice was performed. The information gained from the critical review and survey was used to develop evidence-based guidelines within a multidisciplinary guideline recommendation group.

RESULTS

The guidelines covered the diagnosis, investigation, drug treatment and referral of adult male and female patients with genital chlamydial infection in general practice.

CONCLUSION

Valid guidelines for the management of genital chlamydial infection have been developed for use in British general practice. Appropriate dissemination and implementation of the guidelines should lead to earlier detection and treatment of men and women with chlamydial infection and thereby reduce the incidence of PID, tubal infertility and ectopic pregnancy in women.

[Sexually transmitted diseases]

The control of STD is a public-health priority. Since STD share many behavioural risk factors, efforts to encourage individuals to modify sexual behaviours and adopt safer sexual practices is very important.

[Problems of diagnosis and treatment of cervicitis]

Infectious cervicitis is a common disease in women of reproductive age. The symptoms are not characteristic and they are often neglected by the patient and the physician. Cervicitis is a very important clinical entity, because the infection can ascend to the genital tract. The most common causes for the infectious cervicitis are Chlamydia trachomatic and Neisseria gonorrhoeae. A variety of methods for the precise diagnosis must be employed--gynecologic examination, colposcopy, pathomorphology and cytology and bacteriological examination as well. Therapeutic modalities must include coverage for both Chlamydia trachomatis and Neisseria gonorrhoeae. Bacteriological test of cure is mandatory.

New cases seen at genitourinary medicine clinics: England 1997

Statistics from genitourinary medicine (GUM) clinics provide the most comprehensive source of data on the epidemiology of sexually transmitted infections (STI) in England. Between 1996 and 1997, the total number of diagnoses made in GUM clinics rose by 7% and total diagnoses of acute STIs by 9%. Diagnoses of genital Chlamydia trachomatis, genital warts and gonorrhoea rose by 20%, 8%, and 5%, respectively. Cases of infectious syphilis rose by 26%, most of which was attributable to an outbreak in Bristol. These rises followed substantial rises in acute STIs between 1995 and 1996, and were most pronounced among teenagers and homosexual and bisexual men. The continued growth in numbers of acute STIs is occurring despite the targeting of known risk groups in sexual health education and intervention programmes, and suggests that renewed efforts to improve sexual health are needed.

Simultaneous detection of HPV and other sexually transmitted agents in chronic urethritis

BACKGROUND

Many pathogens may be responsible of Non Gonococcal Urethritis (NGU) with the possible occurrence of symptomatic and asymptomatic mixed viral and bacterial infections. In particular, genital papillomaviruses (HPVs) have been searched since they are linked to both benign and malignant lesions of the penis and urethra and the presence of a potential male carried state has received limited scrutiny while the screening of sexually active females has received substantial attention.

METHODS

In male patients affected by chronic NGU, the presence of DNA of Chlamydia trachomatis, herpes simplex virus (HSV) type 1 and 2 and human papillomaviruses by PCR and the occurrence of Gram positive and Gram negative micro-organisms, of Mycoplasma hominis and Ureaplasma urealyticum, by conventional cultural methods have been investigated.

RESULTS

Results obtained indicated a high percentage of mixed infections, up to 36%. Genital HPV DNA was detected in 31% of specimens positive for two or more agents, and HSV DNA was detected in 10% of studied population.

CONCLUSIONS

The concomitant presence of different infectious agents could determine latent, sub-clinical or chronic infections with periodic reactivation. In particular results suggest that HPV and HSV may stimulate cytokine production which can up regulate the expression of other infectious agents and may be responsible for latent chlamydial infections characterised by the persistence of this micro-organism in an altered form, viable but in a culture negative state. Therefore an increased awareness of mixed infections is relevant to define the management and treatment of chronic urethritis.

PCR testing of genital and urine specimens compared with culture for the diagnosis of chlamydial infection in men and women

Our aim was to determine the number of chlamydial infections detected by Cobas Amplicor CT/NG multiplex polymerase chain reaction (PCR) testing of genital and first-voided urine (FVU) specimens compared with routine culture. Two hundred and eighty-six female and 276 male patients attending the Genito-Urinary Medicine (GUM) Unit at Edinburgh Royal Infirmary were included in the study. Case notes were analysed retrospectively to determine how many infected patients would not have been treated had diagnosis relied on routine culture. Polymerase chain reaction on FVU from women had a sensitivity, specificity, positive and negative predictive value of 91%, 100%, 100% and 99.1%: corresponding values for genital PCR and culture were 96%, 100%, 100%, 99.6% and 65%, 100%, 100%, 96.7% respectively. PCR on FVU from men had a sensitivity, specificity, positive and negative predictive value of 96%, 99.1%, 92.6% and 99.5%: corresponding values for genital PCR and culture were 89%, 99.5%, 95.8%, 98.6% and 48%, 100%, 100%, 94.3% respectively. In both men and women genital PCR and urine PCR were significantly more sensitive than culture. PCR almost doubled the number of patients detected by culture (49 vs 27). Of the 22 cases detected only by PCR 8 would not have received treatment on the basis of clinic treatment policy.

Pelvic inflammatory disease. From diagnosis to prevention

Pelvic inflammatory disease (PID) refers to infection of the uterus, fallopian tubes, and adjacent pelvic structures that is not associated with surgery or pregnancy. PID causes major medical, social, and economic problems worldwide. Long-term sequelae, most notably tubal factor infertility and ectopic pregnancy, are common and extremely costly to the healthcare system. The most important causative micro-organisms are Chlamydia trachomatis, Neisseria gonorrhoeae, and micro-organisms associated with bacterial vaginosis. The clinical spectrum of PID ranges from subclinical endometritis to severe salpingitis, pyosalpinx, tubo-ovarian abscess, pelvic peritonitis, and perihepatitis. Clinical diagnosis of PID has limitations. The clinical diagnostic criteria are insensitive and nonspecific, and false-positive and false-negative diagnosis is common; however, direct visual diagnosis is not always feasible, requires general anesthesia, and is costly. More research is needed of noninvasive diagnosis of PID. Current treatment guidelines call for broad-spectrum antimicrobial coverage. Screening for asymptomatic chlamydial infection is the mainstay of prevention of PID. Emerging evidence from randomized controlled trials provides strong evidence that intervention with selective screening for chlamydial infection effectively reduces the incidence of PID.

Etiology of nongonococcal nonchlamydial urethritis

The majority of cases of acute nongonococcal urethritis (NGU) are due to causes other than infection with Chlamydia trachomatis. Pathogens implicated as causes of nonchlamydial nongonococcal urethritis (NCNGU) include Mycoplasma genitalium, Ureaplasma urealyticum, Trichomonas vaginalis, and primary infection with herpes simplex virus. In a majority of cases of acute NCNGU, no pathogen can be isolated. The etiology of chronic NCNGU is unknown.

The enigmatic cervix

Because of the serious complications associated with cervicitis, detection of the clinical signs of cervicitis is paramount importance to the reproductive health of young women. This article discusses causes of infectious and noninfectious cervicitis, as well as, the interactions of cervicitis with well-known diseases.

Urethritis. Diagnosis of nongonococcal urethritis

Nongonococcal urethritis (NGU) frequently occurs in men after infection of the lower genital tract with a genital pathogen and is mostly associate with complaint of a scanty, thin discharge and urinary symptoms. Management of NGU includes clinical examination, microbiological diagnosis of genital pathogens, and efficient treatment as well as contact tracing. Diagnosis, especially of the Chlamydia trachomatis, the most frequent cause of NGU, has improved by using amplification assays for the detection of DNA or rRNA. These new methods have the advantage of a higher sensitivity especially for specimens with a low number of infectious agents. In addition, they enable the use of urine as a noninvasive specimen type.

Balanitis

Balanitis, inflammation of the glans penis, is a frequently presenting genital disorder. It may be infectious and sexually transmissible, or commonly represents a noninfectious dermatologic condition. Accurate diagnosis is essential for management.

Screening for sexually transmitted infections

The high prevalence of STI in many developed countries; their costly physical, psychological, and relationship sequelae; and their association with the acquisition and transmission of HIV necessitate the introduction of screening programs, especially those that encourage opportunistic screening in diverse health care and community settings. This requirement is accompanied by the need for better awareness and education of health care professionals, especially those working in primary care or in sexual health disciplines, and knowledge of local prevalence and other epidemiologic factors to allow cost-effective targeting of high-risk groups. Such programs should be accompanied by the development of effective clinical alliances between those undertaking screening, the diagnostic microbiology laboratories, and clinicians with local responsibility for case management and public health control. The development of new molecular methods of diagnosis for the common bacterial STI permits screening in the community to be extended. This will help detect those asymptomatic persons who would not otherwise access health services but who may act as important vectors in STI spread and who continue to maintain local reservoirs.

Urethritis treatment

This article reviews most common sexually transmitted causes of urethritis in men. Outlined are clinical presentation, approach, diagnostic work-up, and treatment for the most common pathogens, as well as the cost issues related to antibiotic therapy. Common management problems in urethritis are also discussed.

Rapid identification and speciation of Haemophilus bacteria by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

Several species of the genus Haemophilus are well known etiological agents of pneumonia, meningitis, conjunctivitis, epiglottitis and chancroid. However, identification and speciation of Haemophilus is both time consuming and labor intensive. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI/TOF-MS) has been used by several investigators to profile proteins from intact and disrupted bacteria; consequently, MALDI/TOF-MS has emerged as a powerful tool in diagnostic bacteriology. This paper reports the use of MALDI/TOF-MS as a technique for the rapid identification and speciation of Haemophilus. This technique was used to not only identify the pathogen, H. ducreyi, but also to determine strain differences from different isolates. Mass spectral 'fingerprints' were obtained which permitted the rapid speciation of not only pathogenic forms of Haemophilus, but also those bacteria which are normally regarded as non-pathogenic and members of the normal flora. MALDI/TOF mass spectra can be acquired in 10 min, allowing the identification of Haemophilus spp. within 24 h rather than the 48 h or more needed for traditional bacteriological methods. In addition, these are the first mass spectral fingerprints available in the literature for many of these organisms.

Validation of national algorithms for the diagnosis of sexually transmitted diseases in Brazil: results from a multicentre study

OBJECTIVE

To validate STD flow charts for the management of genital discharge and genital ulcer currently recommended by the National STD Control Programme in Brazil.

METHODS

A study was conducted in five Brazilian STD clinics from January to June 1995. After an interview, a clinical examination was performed by a physician, who recorded a presumptive diagnosis, based on his/her clinical experience. This diagnosis was compared with a gold standard laboratory diagnosis in order to calculate sensitivity, specificity, and positive predictive value of the clinical diagnosis. The validity of the simulated national flow charts was assessed using the same method.

RESULTS

A total of 607 men and 348 women participated in the study. Gonorrhoea was the aetiology most frequently detected in men with urethral discharge. The sensitivity of the clinical diagnosis was far lower than the sensitivity fo the national flow chart, using the syndromic approach, for both gonococcal and chlamydial urethritis. Adding a simple laboratory test (Gram stain) to the national flow chart increased the specificity and positive predictive value for gonorrhoea. Among the women with vaginal discharge, a cervical infection was detected in 17%, a vaginal infection in 74%, and mixed infection in 9%. The sensitivity of the diagnosis for cervical infection increased from 16% (clinical aetiological approach) to 54% (when adding a syndromic approach) and to 68% when adding a risk assessment, as in the national flow charts. The cure or improved rate of genital ulcers was 96% after 1 week.

CONCLUSIONS

The results of the study will help to convince policy makers and those involved in training healthcare workers in Brazil of the public health advantages of the syndromic approach, as an essential part of STD/HIV control activities.

Comparison of clinically directed, disease specific, and syndromic protocols for the management of genital ulcer disease in Lesotho

OBJECTIVE

To evaluate two protocols for the syndromic management of genital ulcer disease (GUD) in Lesotho, southern Africa and to compare the performance of these protocols with that of a conventional disease specific approach.

METHODS

A cross sectional study was conducted among consecutive patients with GUD attending an STD clinic in Maseru, Lesotho. The clinical diagnoses were made by using predefined criteria at the initial visit before the performance of laboratory tests. Attempts were made to detect the specific aetiology of the genital ulcers using PCR assays and syphilis serology. The results of PCR assays and syphilis serology were used as the gold standard against which the performance of the management approaches were applied.

RESULTS

Of 100 patients initially recruited into the study, Haemophilus ducreyi infection was detected in 56%, herpes simplex virus in 26%, Treponema pallidum in 23%, and lymphogranuloma venereum in 7%. No pathogens were detected in 6% of patients. 17% of patients had mixed infections. Sensitivity, specificity, positive and negative predictive values of the three management protocols for GUD were compared after applying each to the study population. Theoretically, the lowest correct treatment rate would have been obtained by using the disease specific protocol (62%) compared with more than 90% in both syndromic management protocols. Considerable overtreatment for primary syphilis would occur following application of both syndromic protocols. This would be the result of the overdiagnosis of chancroid, in particular the misdiagnosis of genital herpes as chancroid, which would receive treatment for syphilis unnecessarily. The HIV seroprevalence among these patients was 36%. A significantly higher rate of HIV seropositivity was detected among the patients with herpes simplex virus infection when compared with those patients having other causes of genital ulcer disease (58% v 27%; odds ratio 3.73; 95% CI 1.26-11.26; p = 0.01).

CONCLUSIONS

Poor sensitivity, specificity, and predictive values were recorded when the disease specific protocol was applied to the study population. In contrast, the syndromic management protocols provided adequate treatment for more than 90% of patients with GUD. Protocol C, which identified a minority of cases of genital herpes, was found to have an advantage when compared with protocol B (all patients with genital ulcer disease treated for both syphilis and chancroid) in that 29% of genital herpes cases would receive appropriate counselling.

Reproductive tract infections in primary healthcare, family planning, and dermatovenereology clinics: evaluation of syndromic management in Morocco

OBJECTIVE

To determine where and with what symptoms women seek care for reproductive tract infections (RTI) in Morocco and to guide allocation of resources for training and treatment for RTIs.

METHODS

A primary healthcare centre (PHC), a family planning centre (FPC), and a specialty dermatovenereology clinic (SC) were selected in each of three urban areas. Women with symptoms of vaginal discharge, lower abdominal or pelvic pain, or genital lesions (genital ulcer or warts) underwent interviews, physical examinations, serological testing for human immunodeficiency virus (HIV) and syphilis, and collection of vaginal fluid for microscopic examination, and urine for detection of Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (GC) by ligase chain reaction (LCR).

RESULTS

Over 8 months, 1238 women enrolled, including 61.8% at PHCs, 34.8% at FPCs, and 3.4% at SCs. Overall, 54% complained of vaginal discharge, of whom 8.8% had GC or CT infection and 30.1% had trichomoniasis (TV) or bacterial vaginosis (BV); 24.9% complained of lower abdominal pain with or without vaginal discharge, of whom 7.3% had GC or CT and 22.6% had TV or BV. GC or CT infections were found in 10.1% of PHC and 5.4% of FPC patients; while TV and/or BV infections were found in 28.7% and 22.8%, respectively. GC or CT infection was associated with perceived risk behaviours of the male partner (for example, belief partner is unfaithful) more often than with reported risk behaviours of the women themselves. For vaginal infections, a modified World Health Organisation (WHO) test algorithm for vaginal discharge involving risk assessment plus speculum and bimanual examination was 98.0% sensitive at PHCs and 90.8% at FPCs, with positive predictive value (PPV) of 33.4% at PHCs and 26.8% at FPCs. For GC or CT infections this algorithm was 60.6% sensitive at PHCs and 85.7% sensitive at FPCs; but PPV was only 9.9% and 9.0% respectively, little higher than the background prevalence of these infections. An RTI algorithm (Morocco specific) had comparable sensitivity and PPV for vaginal infection, and for cervical infection was less sensitive but had much higher PPV (26.9% for PHCs and 26.7% for FPCs).

CONCLUSION

Women with complaints of vaginal discharge and/or lower abdominal pain presented to PHC and FP clinics, not to SCs. PHCs and FPCs should therefore receive resources for management of vaginal discharge. Both the test algorithm and the new RTI algorithm were useful in allocating treatment for vaginal infection, but only the RTI algorithm discriminated in selecting women with cervical infection. Even with the RTI algorithm, which limited treatment for cervical infection to risk assessment positive patients with signs of cervical infection or PID, the PPV for cervical infection was low, potentially resulting in frequent overtreatment and problems of partner notification.

Polymerase chain reaction as a diagnostic tool

Although the method of polymerase chain reaction (PCR) is technical, the concept is simple: PCR is a sequential process that explores a sample for the presence of a known sequence of DNA or RNA. Chapter sections cover specific applications of PCR to infectious diseases with rheumatic manifestations.

False-negative results of a ligase chain reaction assay to detect Chlamydia trachomatis due to inhibitors in urine

The aim of this study was to assess the presence of inhibitors in urine specimens causing false-negative results in a commercial Chlamydia trachomatis gap-filling ligase chain reaction (Gap-LCR) assay. On testing of urine samples by the Gap-LCR assay and urethral swab specimens by cell culture, 73 (19%) Chlamydia trachomatis positive subjects were detected among 382 men attending a clinic for sexually transmitted diseases. In 56 subjects, the agent was detected in both the urine and the urethral samples, while 309 subjects were negative in both tests. In seven subjects urine samples were Gap-LCR positive (confirmed by a different Gap-LCR assay), but the corresponding urethral swab samples were cell culture-negative. In another ten subjects the urethral swab samples were cell culture positive, but their urine samples were Gap-LCR negative. Subsequent re-analysis of the urine samples including the addition of external Chlamydia trachomatis DNA indicated full or partial inhibition in nine of the cell culture-positive Gap-LCR negative subjects. When urine preparations were freeze-thawed and diluted prior to testing, Chlamydia trachomatis was detected in six of the ten initially Gap-LCR-negative samples. Gap-LCR inhibitors were present in at least nine (12%) of the 73 urine preparations from the Chlamydia trachomatis positive individuals. Identification of samples containing Gap-LCR inhibitors and subsequent processing to reduce the inhibition increased the sensitivity of the test from 86% to 95%.