Molecular Differentiation of Treponema pallidum Subspecies in Skin Ulceration Clinically Suspected as Yaws in Vanuatu Using Real-Time Multiplex PCR and Serological Methods

We developed a TaqMan-based real-time quadriplex polymerase chain reaction (PCR) to simultaneously detect Treponema pallidum subspecies pallidum, T. pallidum subsp. pertenue, and T. pallidum subsp. endemicum, the causative agents of venereal syphilis, yaws, and bejel, respectively. The PCR assay was applied to samples from skin ulcerations of clinically presumptive yaws cases among children on Tanna Island, Vanuatu. Another real-time triplex PCR was used to screen for the point mutations in the 23S rRNA genes that have previously been associated with azithromycin resistance in T. pallidum subsp. pallidum strains. Seropositivity by the classical syphilis serological tests was 35.5% among children with skin ulcerations clinically suspected with yaws, whereas the presence of T. pallidum subsp. pertenue DNA was only found in lesions from 15.5% of children. No evidence of T. pallidum subsp. pertenue infection, by either PCR or serology was found in ∼59% of cases indicating alternative causes of yaws-like lesions in this endemic area.     

A possible mechanism of macrolide resistance among multiple resistant Campylobacter jejuni and Campylobacter coli isolated from Thai children during 1991-2000

A total of 495 Campylobacterjejuni and 122 C. coli isolated from Thai children were screened for macrolide (erythromycin and azithromycin) resistance by disk diffusion assay. Minimum inhibitory concentrations for erythromycin, azithromycin, nalidixic acid, ciprofloxacin, tetracycline, streptomycin, gentamicin and chloramphenicol were further determined for these macrolide-resistant Campylobacter isolates. Presence of known point mutations resulting in reduced susceptibility to macrolides was investigated by PCR and DNA sequencing. Seventeen percent (23/122) of C. coli and 2.4% (12/495) of C. jejuni isolates were resistant to macrolides. By sequencing domain V of the 23S ribosomal DNA from all 35 macrolide-resistant isolates, a known point mutation of 23S rRNA associated with reduced susceptibility to macrolides was detected in all isolates except one. Among the macrolide-resistant isolates, all were multiply resistant to nalidixic acid and ciprofloxacin, of which the latter is the preferred antimicrobial used for diarrheal treatment in Thailand. Furthermore, most macrolide-resistant isolates were also resistant to tetracycline and streptomycin. The spread of macrolide and quinolone resistant Campylobacter should be monitored closely in Thailand and elsewhere as these antimicrobials are preferred drugs for treatment of diarrhea.     

Chronic Progressive Disseminated Histoplasmosis in a Mexican Cockfighter

Yaws is a neglected infectious disease that affects mostly children and adolescents living in poor, rural communities in humid, tropical areas of Africa, southeast Asia, and the Pacific Islands. The etiological agent of yaws, Treponema pallidum subspecies pertenue (T. pertenue), was discovered by Aldo Castellani in 1905 shortly after Schaudinn and Hoffmann discovered the etiological agent of syphilis, T. pallidum subspecies pallidum. The discovery of T. pertenue enabled the development of animal models and the identification of an effective antibiotic treatment (i.e., penicillin) for yaws. A World Health Organization (WHO) mass treatment campaign from 1952 to 1964 reduced the global burden of yaws by 95%, but failed to eradicate this disease. Today, 110 years after Castellani''s discovery of T. pertenue, yaws is again targeted for eradication. Recent advances in the treatment and diagnosis of yaws improve the likelihood of success this time. However, several challenges must be overcome to make the goal of yaws eradication attainable.Yaws is an infectious disease that affects mostly children and adolescents, aged 2–15 years, who live in poor, rural communities in humid, tropical areas of Africa, southeast Asia, and the Pacific Islands.¹ Yaws is currently thought to be endemic in at least 12 countries, but adequate surveillance data are lacking.² This disease is transmitted by contact of broken or abraded skin with the exudate of yaws lesions. Clinical manifestations of yaws are divided into stages. Early stage skin lesions are infectious and can persist for weeks or months. Involvement of the bones of the upper and lower limbs and the fingers and toes can cause pain and digital swelling. After the early stage lesions subside due to the host immune response, the patient enters a latent stage that can be lifelong. In about 10% of untreated patients, the infection progresses to the tertiary stage that is characterized by destruction of tissue, bone, and cartilage resulting in disfigurement and disability.¹The etiological agent of yaws, T. pallidum subspecies pertenue (i.e., T. pertenue), was discovered in 1905 by Aldo Castellani, a physician and expert in neglected tropical diseases. Castellani had observed spiral-shaped bacteria in lesion material from yaws patients in Sri Lanka (formerly Ceylon), but did not ascribe significance to this observation. However, after learning of the 1905 discovery of the syphilis agent, T. pallidum subspecies pallidum (i.e., T. pallidum), by Schaudinn and Hoffmann³ and cognizant of the similarities of syphilis and yaws, Castellani examined new scrapings from yaws lesions. Using special staining techniques, he again observed delicate, faintly stained spirochetes that were morphologically indistinguishable from T. pallidum. Castellani''s preliminary findings were presented to the Ceylon Branch of the British Medical Association in June 1905.⁴ After studying lesion material from additional yaws cases, he proposed “Spirochaeta pertenuis” (i.e., T. pertenue) as the etiological agent of yaws.^5,6 Castellani''s findings were soon confirmed by the December 1905 report of Wellman, who had observed spirochetes in the lesions of an African yaws patient.⁷The discovery of T. pertenue enabled the development of animal models for experimental studies of yaws. Castellani investigated the infectious nature of the noncultivable T. pertenue in monkeys.⁸ He showed that 1) monkeys could be experimentally infected with an inoculum prepared from the lesions of yaws patients, 2) the inoculum could be rendered noninfectious by removal of T. pertenue by filtration, and 3) yaws could be serially transferred in monkeys, and T. pertenue was invariably present in “pure culture” in the monkeys'' non-ulcerated lesions. Using a modification of Wassermann''s complement fixation test for serodiagnosis of syphilis, Castellani detected antibody reactivity in the sera of yaws-infected monkeys, but not naïve monkeys, to antigen in an extract of yaws lesions.⁸ In addition, Castellani demonstrated that yaws-infected monkeys were not immune to syphilis and, conversely, that syphilis-infected monkeys were not immune to yaws (i.e., there is no cross-protection conferred by infection).⁸ This observation along with the previously published work of Neisser and co-workers,⁹ dispelled the belief that syphilis and yaws were the same disease, but with different clinical manifestations because of host genetics and climate. In 1910, Nichols reported that rabbits could be infected intratesticularly with T. pertenue and proposed that these animals could provide a more practicable model of yaws for the investigation of immunity and treatments.¹⁰Because of the biological similarities of T. pallidum and T. pertenue, there was optimism that syphilis treatments would be effective for yaws. In 1907, Castellani reported the results of various syphilis treatments on small numbers of yaws patients.¹¹ He noted a dramatic improvement of yaws lesions following administration of mercury by the oral or intramuscular route. However, as observed with syphilis, mercurials alone were not curative because yaws lesions usually reappeared after treatment cessation. In 1910, salvarsan (compound 606), an arsenical developed by Ehrlich in Germany, showed promising results for syphilis treatment.¹² Castellani noted that salvarsan was more effective than mercury for yaws treatment.^13,14 Strong (1911), Alston (1912), Cockin (1913), and McDonald (1915) reported that one injection of salvarsan, given intravenously or intramuscularly, could cure early and late yaws.^15–18 The few relapses, or possible reinfections, which occurred were successfully retreated with salvarsan. Interestingly, salvarsan appeared to be more effective for yaws than it was for syphilis. Nichols postulated that the need for prolonged treatment of syphilis with salvarsan was due to the more invasive nature of T. pallidum, which enabled it to survive in body sites where the concentration of salvarsan was subtherapeutic.¹⁹ In 1914, Ehrlich developed neosalvarsan (compound 914), which was easier to administer and had less side effects than salvarsan.¹² Harper²⁰ and Greggio¹⁴ reported that neosalvarsan was effective for yaws treatment. Later, mapharsen, a partially oxidized product of salvarsan, was found to cure syphilis.¹² This arsenical, which was patented in 1937, was less toxic than neosalvarsan and could be given in smaller doses. Longley and co-workers²¹ showed that both mapharsen and neosalvarsan were effective for curing rabbits infected with yaws. However, the use of mapharsen for yaws treatment was limited because arsenicals essentially became obsolete when penicillin became available in the 1940s. Following the 1943 report of Mahoney and co-workers²² on the curative action of penicillin for syphilis, there were multiple reports of small numbers of yaws cases that were cured with penicillin.²³ Dwindelle and co-workers²³ treated 500 Haitian patients in early yaws with penicillin and demonstrated the therapeutic efficacy of this drug, which became the mainstay for the treatment and control of yaws.Nearly 50 years after Castellani''s discovery of T. pertenue, a major effort was made to eradicate yaws. From 1952 to 1964, the WHO, in concert with the United Nations Children''s Fund (UNICEF), sponsored a mass treatment campaign in 46 countries.^1,2,24 About 300 million people were screened and 50 million or more cases and their contacts were treated with an intramuscular injection of long-acting penicillin. By the end of this campaign, the global burden of yaws was reduced by 95% to 2.5 million cases. Unfortunately, the lack of sustained surveillance and the waning of commitment and resources resulted in the reemergence of yaws in Africa, Asia, and the Pacific in the late 1970s. Although control activities were renewed in several countries and efforts were made to galvanize support from the international community, yaws eradication failed.Today, 110 years after the discovery of T. pertenue, yaws is again targeted for eradication. The WHO''s “Morges strategy” for yaws eradication by 2020 is based on mass treatment of individuals in endemic communities followed by clinical and serological surveys at 6-month intervals to detect and treat the remaining cases and their contacts.^24,25 Two recent advances for treatment and diagnosis of yaws should greatly aid eradication efforts. First, Mitja and others showed in two separate studies conducted in Papua New Guinea that a single, oral dose of azithromycin (30 mg/kg body weight; maximum dose of 2 g) is as effective as intramuscular benzathine penicillin (1.2 million units (MU) for adults, 0.6 MU for children) for yaws treatment and is more feasible to administer in the field.^26,27 Azithromycin, which has recently replaced penicillin as the WHO-preferred drug for yaws, will be used for mass treatment in communities where yaws is endemic. Second, Ayove and others²⁸ showed that a point-of-care serological test for syphilis diagnosis, the Dual Path Platform (DPP) Syphilis Screen and Confirm, is sufficiently sensitive and specific for rapid diagnosis of yaws under field conditions using finger-stick blood. This important development obviates the need for venipuncture to obtain serum samples and for transport of serum samples to a distant laboratory for testing. The DPP test will be used to detect yaws cases that are difficult to diagnose based on clinical symptoms because unrelated bacteria, such as Haemophilus ducreyi, can cause phenotypically similar skin lesions.¹ The DPP test may also be used for monitoring the effectiveness of azithromycin treatment.Undoubtedly, many challenges must be overcome for yaws eradication to succeed. Aside from major financial and commitment issues, several uncertainties related to the biology and epidemiology of yaws could impede this endeavor.^1,2,29 Because there is no vaccine to prevent infection, antibiotic treatment must be effective to interrupt transmission of yaws. The use of oral azithromycin as the first-line drug, while warranted based on logistics, could result in the emergence of azithromycin-resistant T. pertenue, as has been observed with T. pallidum.^30,31 This possibility requires careful monitoring. Furthermore, although the prevalence of yaws is undoubtedly less than it was at the time of the first WHO eradication campaign, the current burden and distribution of yaws are unknown.^2,24 The inability to find and treat yaws cases, particularly in remote areas of previously endemic countries that have not reported cases to the WHO since 1990, could allow yaws to resurface. Despite these concerns, recent advances in the treatment and diagnosis of yaws and a more favorable climate for control of neglected tropical diseases have renewed hope that yaws eradication can be achieved. What more fitting tribute could there be to Aldo Castellani, the discoverer of T. pertenue, than to finally vanquish this “end of the road” disease?     

Antibiotic selection may contribute to increases in macrolide-resistant Treponema pallidum

To determine whether the 23S rRNA mutation that confers macrolide resistance is present in >1 Treponema pallidum strain, 58 isolates collected between 2001 and 2005 were screened for this mutation and for an unrelated sequence that distinguishes between strains. The odds of identifying a macrolide-resistant strain increased over time (P=.006). In subjects who had received macrolides in the previous year, the relative risk of harboring a resistant strain was 2.2 (95% confidence interval, 1.1-4.4; P=.02). The macrolide-resistant strains were not identical. These findings suggest that macrolide resistance may be increasing in multiple strains in response to antibiotic pressure.     

Influence of Macrolide Antibiotics on Promotion of Resistance in the Oral Flora of Children

Background: The long elimination half-life of azithromycin allows subinhibitory serum and epithelial lining fluid (ELF) concentrations over a period of several weeks post treatment, which may have an impact on the emergence of macrolide resistance. In this prospective, open-label, randomized study, four macrolides and the azalide azithromycin were studied for their likelihood to promote resistance in the oral flora of children with respiratory tract infections. Patients and Methods: Children were randomly assigned to receive azithromycin, clarithromycin, erythromycin, roxithromycin and josamycin. Throat swabs were obtained prior to treatment and weekly for 6 weeks. Minimum inhibitory concentrations (MICs) for resistant strains were assessed by E-test and National Committee for Clinical Laboratory Standards (NCCLS) broth microdilution. Results: One week post treatment, up to 90% of children harbored macrolide-resistant strains in their oral flora. Except for azithromycin, the percentage of patients colonized by resistant organisms decreased to a rate of 17% for clarithromycin (10/60), erythromycin (2/12) and josamycin (2/12) and 33% for roxithromycin (4/12) after 6 weeks. In the azithromycin group, 85% (51/60) of patients were colonized by macrolide-resistant organisms after 6 weeks, 11.6% (7/60) of chiildren suffered from reinfection. Conclusion: Azithromycin therapy appears to put selective pressure on the infective and native flora of children, promoting the carriage of marcolide-resistant strains. Received: June 6, 2000 · Revision accepted: June 2, 2001     

Diagnosis of treponemal co‐infection in HIV‐infected West Africans

Objectives To evaluate the performance of two enzyme immunoassays (EIA), Murex and ICE, and the Determine TP point‐of‐care test (POCT) in diagnosing treponemal infection (syphilis or yaws) in patients attending a large HIV clinic in Ghana; to determine the prevalence of treponemal co‐infections; and to characterise demographic and clinical features of patients with infection. Methods Samples were tested with EIAs and rapid plasma reagin (RPR), then POCT and reference assays for Treponema pallidum to determine prevalence of active and past infection. Sensitivity and specificity of each assay were calculated and demographic and clinical characteristics of patients compared. Data were collected from case notes of patients retrospectively. Results Overall, 45/284 patient samples (14.8%, 95% CI, 11.1–19.4%) were Treponema pallidum particle agglutination (TPPA) positive, and of these, 27 (64.3%) were RPR positive and 4 (8.9%) were treponemal IgM positive. Both EIAs and Determine TP POCT showed high sensitivities and specificities for identifying infection although RPR was less reliable. Clinical features of syphilis or yaws were rarely identified in TPPA‐positive patients suggesting most had previous or late latent infection. Treatment of various intercurrent infections using short courses of antibiotics active against T. pallidum was common in the clinic. Conclusions A high proportion of this HIV‐infected cohort showed evidence of treponemal infection. Both EIAs as well as the POCT were practical and effective at diagnosing treponemal co‐infection in this setting. RPR alone was unreliable at identifying active treponemal co‐infection, however might be useful in some settings where treponemal‐specific assays are unaffordable.     

Mapping the Epidemiology of Yaws in the Solomon Islands: A Cluster Randomized Survey

Yaws, a non-venereal treponemal disease, is targeted for eradication by 2020 but accurate epidemiological data to guide control programs remain sparse. The Solomon Islands reports the second highest number of cases of yaws worldwide. We conducted a cluster randomized survey of yaws in two provinces of the Solomon Islands. One thousand four hundred and ninety-seven (1,497) children 5–14 years of age were examined. Clinical signs of active yaws were found in 79 children (5.5%), whereas 140 children (9.4%) had evidence of healed yaws lesions. Four hundred and seventy (470) (31.4%) children had a positive Treponema pallidum particle agglutination assay (TPPA). Two hundred and eighty-five (285) children (19%) had a positive TPPA and rapid plasma regain assay. Risk of yaws increased with age and was more common in males. The prevalence of yaws at village level was the major risk factor for infection. Our findings suggest the village, not the household, should be the unit of treatment in the World Health Organization (WHO) yaws eradication strategy.     

Diagnóstico molecular de la sífilis

Syphilis is a sexually transmitted infection caused by Treponema pallidum subsp. pallidum with an increasing incidence in Spain and in the rest of the world. Diagnosis is based mainly on serology, since direct diagnosis by dark field microscopy presents difficulties that limit its widespread use. Molecular biology techniques can be a useful tool for diagnosis in primary and secondary syphilis, although not all types of samples show the same behaviour. These techniques are also useful for the diagnosis of congenital syphilis. They are not recommended, however, for neurosyphilis, due to the low sensitivity of polymerase chain reaction in cerebrospinal fluid. These techniques have been used to study the controversial origin of syphilis, and, through the enhanced Centers for Disease Control method, to perform typing, which helps to elucidate the epidemiology of this infection. Finally, molecular techniques can detect mutations related to macrolide resistance, which are present in a very high percentage of infections.     

Sífilis

Syphilis is an infectious disease caused by the spirochaete Treponema pallidum subsp. pallidum which is transmitted by sexual contact or vertical transmission during pregnancy. The incidence of syphilis has increased in the last years, mainly among men who have sex with men. Without treatment, the disease develops into different clinical stages, being able to present cardiovascular or irreversible neurological complications after a number of years. The disease is classified as early syphilis - primary, secondary and early latent syphilis (less than 12 months) - which is contagious, and as late syphilis - late latent and tertiary syphilis- which is rarely contagious. Diagnosis and management are often a challenge because of its diversity of manifestations and the difficulty of interpretation of serological tests. The treatment of syphilis is based on penicillin or doxycycline in allergic patients. Treatment failure because of resistance has been described with azithromycin. The follow up with a serological test is recommended in all patients with syphilis in order to ascertain cure after the treatment and to diagnose possible reinfections.     

Serosurvey of anti-treponema pallidum (syphilis), anti-hepatitis C virus and anti-HIV antibodies in homeless persons of São Paulo city,southeastern Brazil

Homeless persons have been considered as one of the most susceptible populations to sexually transmitted infections. In Brazil, these population experienced an increase of 140% from 2012 to 2020. Accordingly, the present study aimed to assess the seroprevalence of anti-Treponema pallidum, anti-HCV, anti-HIV antibodies, and the risk factors associated with homeless persons in a daytime attendance shelter of São Paulo city during the syphilis epidemic in Brazil. Blood samples of 116 volunteers and epidemiological data were conveniently collected in the shelter from June through August 2018. Detection of syphilis, HCV, and HIV antibodies was performed by chemiluminescent microparticle immunoassay (CMIA). CMIA-reagent samples for anti-T. pallidum antibodies were confirmed by Venereal Disease Research Laboratory (VDRL) non-treponemal test. VDRL non-reagent samples were confirmed by treponemal rapid immunochromatographic test. A rapid immunoblot assay confirmed seropositivity to HIV. Overall, anti-T. pallidum antibodies were observed in 29/116 (25.0%), anti-HCV antibodies in 4/116 (3.4%), and anti-HIV antibodies in 2/116 (1.7%) individuals, both co-infected with anti-T. pallidum antibodies. Associated risk factors for syphilis in homeless persons were being born or previously living in another city (p = 0.043) and becoming homeless due to family conflicts (p = 0.035). Besides homeless vulnerability, worldwide shortage of benzathine penicillin supply and increasing of syphilis testing access through rapid testing in primary health care services may have also impacted disease spreading at the time. The prevalence of syphilis found herein is the highest worldwide to date in this population.     

Origins and spread of pfdhfr mutant alleles in Plasmodium falciparum

The emergence and spread of Plasmodium falciparum parasite resistant to sulfadoxine and pyrimethamine (SP) poses a serious public health problem. Resistance is caused by point mutations in dihydrofolate reductase (pfdhfr) and dihydropteroate synthase (pfdhps), the two key enzymes in the folate biosynthetic pathway. The use of microsatellite markers flanking pfdhfr has recently shown that the invasion of limited resistant lineages may explain the widespread SP resistance in many endemic regions. In Africa, however, multiple indigenous origins of pfdhfr triple mutants have been demonstrated. More new independent lineages and routes of geographical spread of resistance may be found by further molecular evolutionary analyses using samples from various endemic regions. Here, I review recent studies about the history of SP usage and the evolution and spread of resistant lineages while addressing the technical issue of microsatellite analysis.     

Simultaneous colonisation of Helicobacter pylori with and without mutations in the 23S rRNA gene in patients with no history of clarithromycin exposure

BACKGROUND: It was recently reported that A to G transition mutations at positions 2143 and 2144 in the 23S rRNA gene are associated with clarithromycin resistance in Helicobacter pylori. AIMS: To study the incidence and mechanism of development of clarithromycin resistance by analysing these mutations. SUBJECTS: Eighty two H pylori positive patients who had an endoscopic examination and no history of treatment with macrolide antibiotics. METHODS: Clarithromycin resistance was screened for by polymerase chain reaction-restriction fragment length polymorphism of the 23S rRNA gene coupled with antibiotic susceptibility testing. In clinical isolates with mutations or resistance, mutations in individual colonies were analysed by direct sequencing. RESULTS: Of the 79 amplicons (DNA fragments amplified by polymerase chain reaction), Alw26I and MboII digestion disclosed the mutation in four (5%) and one (1%) respectively. However, the Alw26I cleavage was incomplete in two of the four amplicons, as was the MboII cleavage. Individual colony analysis of the isolates with incomplete cleavage patterns showed the presence of both wild type and mutated strains in the 23S rRNA genes. CONCLUSIONS: Both clarithromycin sensitive and resistant strains colonised in some patients with no history of exposure to macrolides. The results suggest that resistant strains may not be formed but selected by clarithromycin administration.     

Antimicrobial resistance characteristics of clinical isolates of Streptococcus pyogenes

OBJECTIVE: To determine the antibiotic susceptibility of recent isolates of Streptococcus pyogenes and to evaluate the prevalence of macrolide-resistant phenotypes. MATERIAL AND METHODS: In 1999, we conducted a cross-sectional study at Mexico Children's Hospital "Federico Gomez", to analyze one hundred strains of S. pyogenes isolated from 1992 to 1998, in children with uncomplicated pharyngotonsillitis. Strains were frozen at the bacteriology lab until they were analyzed. Strains were tested for susceptibility against some beta-lactams, macrolides and clindamycin. Double-disk testing was carried out to evaluate erythromycin-resistant phenotypes. Data are presented using central tendency measures. RESULTS: All tested strains were not resistant to beta-lactams and clindamycin; 16% of the strains were resistant to macrolides and all of them belonged to phenotype M. CONCLUSIONS: Susceptibility testing is recommended to identify possible changes in antibiotic resistance to streptococci.     

Infective Endocarditis Due to Treponema pallidum: A Case Diagnosed Using Polymerase Chain Reaction Analysis of Aortic Valve

Syphilis is a sexually transmitted disease caused by Treponema pallidum. Syphilitic aortitis might coexist in a dysfunctional aortic valve, but the etiology remains unclear, because microbiological diagnosis is difficult. A 62-year-old man with low-grade fever was diagnosed with aortitis and infective endocarditis, due to Treponema pallidum infection, using polymerase chain reaction analysis. This case suggests that syphilis might cause infective endocarditis.     

Laboratory diagnosis of syphilis: A survey to examine the range of tests used in Canada

Laboratory diagnosis of syphilis has undergone major changes in the past decade with the introduction of immunoassays and recombinant Treponema pallidum antigens as screening tools for syphilis infection. To address this change in laboratory practice, a national syphilis laboratory working group was established with members from the Public Health Agency of Canada, provincial public health laboratories across the country as well as sexually transmitted infection researchers, clinicians and epidemiologists. This working group aims to examine how the use of newer immunoassays will affect syphilis diagnosis, surveillance and disease management. To provide a baseline for this work, an e-mail survey was conducted in the fall of 2009 to determine current laboratory practices for syphilis diagnosis in Canada. The most commonly used tests were rapid plasma reagin, enzyme immunoassay, T pallidum passive particle agglutination, venereal disease research laboratory, fluorescent treponemal antibody absorption, line immunoassay and polymerase chain reaction with 92%, 36%, 32%, 20%, 12%, 12% and 12% of the responding laboratories reporting using these tests, respectively. The ultimate goal of this working group will be to update laboratory guidelines for the diagnosis of syphilis, and to identify syphilis surveillance and research priorities in Canada.     

Case report of gastric syphilis in Korea: Clinical features,pathology, management,and prognosis

Rationale:Syphilis is a contagious infectious disease caused by Treponema pallidum. Gastric involvement of syphilis is rare and has nonspecific gastrointestinal symptoms and endoscopic findings. To date, 16 cases have been reported in Korea. Here, we report 2 additional cases of gastric syphilis in men in their 30 second.Patients concerns:Two 35- and 33-year-old men presented with epigastric pain.Diagnosis:The serum venereal disease research laboratory and fluorescent treponemal antibody absorption tests were positive. Esophagogastroduodenoscopy showed multiple variable-sized flat elevated lesions and geographic ulcers with whitish exudates in the antrum and body. Warthin–Starry silver staining of endoscopic biopsy specimens confirmed gastric syphilis.Interventions:The patients were treated with an intramuscular injection of 2.4 million units of benzathine penicillin once a week for 3 weeks.Outcomes:Clinical symptoms and gastric lesions were completely resolved.Lessons:First, gastric syphilis, despite its rarity and nonspecific symptoms and endoscopic findings, should be considered in a rare extracutaneous presentation of syphilis. Second, a high index of clinical suspicion and an accurate diagnosis based on a combination of clinical, radiological, endoscopic, serologic, and histopathologic findings provide an opportunity to identify and treat patients with gastric syphilis.     

What is the clinical impact of macrolide resistance?

Respiratory tract infections are treated empirically. Treatment is based on the likely pathogens and their antibiotic susceptibility. The most common respiratory tract pathogen is Streptococcus pneumoniae. In the United States, approximately 25% to 30% of S. pneumoniae are resistant to erythromycin and other macrolides. There are two mechanisms of resistance: ribosomal methylation that causes high-level resistance, and an efflux pump that causes low-level resistance. Macrolides are ineffective in animal models that use pneumococcal isolates with the methylase- or efflux-mediated resistance mechanisms. There are many case reports that describe clinical failure and isolation of a macrolide-resistant pneumococcus while a patient receives macrolide treatment. Two recent studies that included macrolide-susceptible and macrolideresistant pneumococci showed that breakthrough bacteremia in patients receiving macrolide treatment occurred only with macrolide-resistant isolates. Study of bacteremic disease ensures the pathogenic role of the pneumococcus; however, it underestimates the true clinical impact of macrolide resistance.     

The epidemiological fitness cost of drug resistance in Mycobacterium tuberculosis

The emergence of antibiotic resistance in Mycobacterium tuberculosis has raised the concern that pathogen strains that are virtually untreatable may become widespread. The acquisition of resistance to antibiotics results in a longer duration of infection in a host, but this resistance may come at a cost through a decreased transmission rate. This raises the question of whether the overall fitness of drug-resistant strains is higher than that of sensitive strains—essential information for predicting the spread of the disease. Here, we directly estimate the transmission cost of drug resistance, the rate at which resistance evolves, and the relative fitness of resistant strains. These estimates are made by using explicit models of the transmission and evolution of sensitive and resistant strains of M. tuberculosis, using approximate Bayesian computation, and molecular epidemiology data from Cuba, Estonia, and Venezuela. We find that the transmission cost of drug resistance relative to sensitivity can be as low as 10%, that resistance evolves at rates of ≈0.0025–0.02 per case per year, and that the overall fitness of resistant strains is comparable with that of sensitive strains. Furthermore, the contribution of transmission to the spread of drug resistance is very high compared with acquired resistance due to treatment failure (up to 99%). Estimating such parameters directly from in vivo data will be critical to understanding and responding to antibiotic resistance. For instance, projections using our estimates suggest that the prevalence of tuberculosis may decline with successful treatment, but the proportion of cases associated with resistance is likely to increase.     

Pinta: Latin America's Forgotten Disease?

Pinta is a neglected, chronic skin disease that was first described in the sixteenth century in Mexico. The World Health Organization lists 15 countries in Latin America where pinta was previously endemic. However, the current prevalence of pinta is unknown due to the lack of surveillance data. The etiological agent of pinta, Treponema carateum, cannot be distinguished morphologically or serologically from the not-yet-cultivable Treponema pallidum subspecies that cause venereal syphilis, yaws, and bejel. Although genomic sequencing has enabled the development of molecular techniques to differentiate the T. pallidum subspecies, comparable information is not available for T. carateum. Because of the influx of migrants and refugees from Latin America, U.S. physicians should consider pinta in the differential diagnosis of skin diseases in children and adolescents who come from areas where pinta was previously endemic and have a positive reaction in serological tests for syphilis. All stages of pinta are treatable with a single intramuscular injection of penicillin.The endemic treponematoses, pinta, yaws, and bejel, are caused by spiral-shaped, not-yet-cultivable bacteria of the genus Treponema.^1–3 These neglected infectious diseases (NIDs), for which there are no vaccines, present a diagnostic dilemma to physicians because their clinical manifestations must be differentiated from those of other diseases that affect the skin. Moreover, serological tests cannot differentiate the endemic treponematoses from each other or from venereal syphilis, which is caused by the closely related spirochete, Treponema pallidum subspecies pallidum. Unlike venereal syphilis, the endemic treponematoses are usually acquired by children or adolescents living in poor rural communities in tropical climates (see references ¹ and ² for maps showing the geographical distribution of endemic treponematoses). Whereas venereal syphilis has a global distribution and is transmitted primarily by sexual activity, the endemic treponematoses are transmitted by nonsexual, direct skin-to-skin contact with infectious lesions.Pinta, also known as mal del pinto or carate, is the most benign of the endemic treponematoses since it affects only the skin.^1–3 Pinta was first described in the sixteenth century in the Aztec and Carib Amerindians by Spanish conquistadors and missionaries.⁴ In the 1950s, there were an estimated 1 million cases of pinta in Mexico, Central America, and northern South America. Although pinta was most highly endemic in Mexico and Columbia, cases declined in these countries due to treatment campaigns and possibly due to improvements in living standards, access to health services, and hygiene.^4,5 The World Health Organization (WHO) lists 15 countries in Latin America where pinta was previously endemic. Because of the lack of surveillance data, the current prevalence of pinta is unknown. However, some findings suggest that pinta has not disappeared. For example, in 1982 and 1983, clinical evidence of pinta was discovered in 20% of the examined inhabitants of a remote village in Panama.⁶ In 1987 and 1993, pinta cases were reported in native Indians (Ticuna) living in the Amazon border region of Brazil, Columbia, and Peru.^7,8 Although the last reported case of pinta in Cuba was in 1975, an active, early pinta lesion was identified in a Cuban female who was visiting Austria in 1999.⁹ On the basis of these data, it is plausible that pinta has remained endemic in some remote areas of Latin America where access to health services is limited and living standards have not yet risen.^1,2Like syphilis, pinta is classified into stages (see references ^1–3 for pictures of the clinical stages of pinta). The primary stage is characterized by the presence of one or several papules or erythematous scaly plaques that develop about 3 weeks after infection. The body area most commonly affected is the exposed skin of the extremities. The papule or plaque, which is teeming with infectious treponemes, does not ulcerate, but expands to a diameter of 10 cm or greater. Regional lymphadenopathy is common. During early infection, serological tests for syphilis (STS) may be negative for antibodies to nontreponemal (cardiolipin) and treponemal antigens. Plaques may last for months to years and pigmentary changes may be observed in the plaques. The lesions may heal spontaneously or they may persist and become indistinguishable from the lesions of secondary pinta.The secondary stage usually appears several months after the initial manifestations of the primary stage.^1–3 Small disseminated lesions known as “pintids” may coalesce into plaques. The pintids change from an initial red color to brown, slate-blue, black, or gray colors. Different pigmentation may occur within a pintid. The secondary lesions can remain active and infectious for a long time, leading to extensive depigmentation. STS are positive in the majority of untreated cases.The late (tertiary) stage usually develops 2–5 years after initial infection and is characterized by pigmentary abnormalities (i.e., from dyschromic treponeme-containing lesions to achromic treponeme-free lesions), skin atrophy, and hyperkeratosis.^1–3 The degree of lesion pigmentation can be different in the same patient, resulting in a mottled appearance of the skin, which can persist lifelong. Lesions may turn into various colors (e.g., brown, gray-blue, or black). STS are positive in virtually all untreated cases.The etiological agent of pinta, Treponema carateum, was not identified until over 30 years after the 1905 discovery of the related agents of venereal syphilis and yaws.^4,10–12 Initially, it was thought that a pathogenic fungus caused pinta. However, two observations suggested otherwise. First, laboratory studies of pinta patients'' sera showed that the Wassermann test, an early STS, was positive in the majority of cases. Second, treatments that were effective against syphilis (i.e., mercury and arsenicals) were also effective against pinta. In August 1938, Sáenz and others¹⁰ using dark-field microscopy, demonstrated the presence of spirochetes that were morphologically indistinguishable from the T. pallidum subspecies in exudate from a Cuban pinta patient''s lesions. Subsequently, other investigators reported the presence of spirochetes in pinta lesions. Because the presence of these bacteria was insufficient to prove causality, León-Blanco performed skin inoculation experiments on himself and human volunteers with lesion exudate that contained the spirochetes and succeeded in reproducing the early manifestations of pinta.^4,12 León-Blanco also showed that some immunity to reinfection develops during pinta. Patients with late-stage pinta could not be reinfected, whereas patients whose early-stage pinta had been cured could be reinfected. Furthermore, León-Blanco and Briceno Ross and Iriarte demonstrated that syphilis and yaws patients, respectively, were not immune to infection with pinta, despite the antigenic similarity of the etiological agents.^4,11,12Because animal models are necessary to propagate the T. pallidum subspecies for experimental studies, several investigators attempted to determine if laboratory animals could be infected with T. carateum.¹¹ León-Blanco and Oteiza¹³ reported infection of one of the four rabbits that they inoculated intradermally with exudate from a pinta patient''s lesions. However, they were unable to successfully passage T. carateum from the rabbit''s lesion to other rabbits. Later, Kuhn and others¹⁴ demonstrated that chimpanzees could be infected intradermally and that these animals developed lesions similar to those of pinta patients. Unfortunately, T. carateum isolates are not available for study. Although phylogenetic data obtained via genomic sequencing have enabled the development of techniques to differentiate the T. pallidum subspecies, comparable information is not available for T. carateum.^1,2 Thus, despite the morphological and antigenic relatedness of the agents of pinta and syphilis, molecular knowledge of T. carateum is currently insufficient to warrant classification of this spirochete as a T. pallidum subspecies.Pinta can be treated with a single intramuscular injection of long-acting benzathine penicillin (1.2 MU for adults; 0.6 MU for children), which renders the lesions noninfectious in less than 24 hours.^1,3,11 Information is scant concerning the efficacy of other antibiotics. Although early pinta lesions heal within several months after penicillin administration, this treatment cannot reverse the skin changes of late pinta that can stigmatize those who were infected.⁴ Penicillin treatment was the mainstay for the “National Campaign to Eradicate Mal del Pinto” conducted in Mexico (1960s) and for the WHO campaign against the endemic treponematoses (1952–1964).^1,2,4 A national campaign against yaws that was conducted in Columbia in the 1950s resulted in an almost parallel decline in the incidence of both yaws and pinta, even though pinta was not specifically targeted.⁵ Despite the initial success of these campaigns, the endemic treponematoses, particularly yaws, have resurged due to the lack of sustained resources and political will. The WHO has initiated a campaign to eradicate yaws by 2020 that is based on mass treatment of endemic communities with an oral dose of azithromycin, a macrolide antibiotic with demonstrated efficacy against yaws.^1,2,15 If T. carateum is sensitive to azithromycin as is likely, this treatment strategy could have a concomitant effect on pinta in areas of Latin America where yaws and pinta may be co-endemic. Moreover, if the endemic treponematoses were rolled into the program area of the Pan American Health Organization''s (PAHO''s) Strategic Plan (2014–2019) that targets selected NIDs and focuses on strengthening national capacity for screening, treatment, and surveillance of NIDs, this could facilitate elimination of pinta and yaws in PAHO member countries and would aid WHO''s yaws eradication campaign (www.paho.org/hq/).The possibility of importation of NIDs such as the endemic treponematoses increases as record numbers of migrants and refugees from Latin America continue to enter the United States for economic or political reasons.^2,3,16 Accordingly, physicians should consider pinta in the differential diagnosis of skin diseases for Latin American children and adolescents who come from areas where pinta was previously endemic and have a positive reaction in STS.^3,16 This is critical to guide treatment as well as to avoid the inadvertent psychological harm and legal ramifications that can result from making an incorrect diagnosis of syphilis. Although pinta may be a forgotten disease, it is unlikely to be extinct.^9,17     

突变敏感性分子开关检测肺炎支原体对大环内酯类抗生素的耐药性研究

目的 应用突变敏感性分子开关检测肺炎支原体对大环内酯类抗生素的耐药性。方法 采用微量稀释法检测5种常用大环内酯类抗生素对40株Mp临床分离株的药物敏感性;建立高保真聚合酶和3'硫化修饰引物的分子开关,用分子开关进行Mp临床分离株的PCR扩增,检测其是否存在Mp 23S rRNA 2063、2064和2617 3个热点突变,并通过基因测序进一步确定是否存在点突变,分析点突变与大环内酯类抗生素敏感性之间的关系。结果 5种大环内酯类抗生素中,Mp对14元环的红霉素和克拉霉素耐药程度最高,其MIC≥128 mg/L;对15元环的大环内酯类抗生素阿奇霉素和交沙霉素相对敏感,其中交沙霉素抗Mp活性最高,其MIC≤4 mg/L。用高保真聚合酶和3'硫化修饰引物的分子开关行PCR扩增,检测出35株发生了2063位点基因突变,3株发生2064位点基因突变,未检测出2617位点突变。用基因测序检测到35株Mp发生A2063G的突变,3株发生A2064G的突变,未检测到2617位点突变,与分子开关的检测结果一致,并且2063、2064位点突变Mp株均对大环内酯类药物高度耐药。结论 分子开关可识别23S rRNA基因突变,可用于分析Mp对大环内酯类抗生素的敏感性。