Mycobacterium lepromatosis Lepromatous Leprosy in US Citizen Who Traveled to Disease-Endemic Areas

Systematic Review of Hansen Disease Attributed to Mycobacterium lepromatosis

In 2008, bacilli from 2 Hansen disease (leprosy) cases were identified as a new species, Mycobacterium lepromatosis. We conducted a systematic review of studies investigating M. lepromatosis as a cause of HD. Twenty-one case reports described 27 patients with PCR-confirmed M. lepromatosis infection (6 dual M. leprae/M. lepromatosis): 10 case-patients in the United States (7 originally from Mexico), 6 in Mexico, 3 in the Dominican Republic, 2 each in Singapore and Myanmar, and 1 each in Indonesia, Paraguay, Cuba, and Canada. Twelve specimen surveys reported 1,098 PCR-positive findings from 1,428 specimens, including M. lepromatosis in 44.9% (133/296) from Mexico, 3.8% (5/133) in Colombia, 12.5% (10/80) in Brazil, and 0.9% (2/224) from the Asia-Pacific region. Biases toward investigating M. lepromatosis as an agent in cases of diffuse lepromatous leprosy or from Mesoamerica precluded conclusions about clinicopathologic manifestations and geographic distribution. Current multidrug treatments seem effective for this infection.

Leprosy Caused by Mycobacterium lepromatosis

OBJECTIVES

Leprosy is caused by Mycobacterium leprae or Mycobacterium lepromatosis. This study reviews literature on M lepromatosis and reports on a Mexican family with this infection.

METHODS

The review included all primary studies. Family history and surveys were used to uncover the infection cluster. Genome-based differential polymerase chain reactions were designed to detect etiologic agents.

RESULTS

Since the discovery of M lepromatosis in 2008, 154 cases of M lepromatosis infection from 11 countries in the Americas and Asia have been reported, with most cases coming from Mexico. These cases included diffuse lepromatous leprosy (DLL) and other leprosy forms. Genomes of M lepromatosis strains have lately been sequenced, revealing 3,271,694 nucleotides and approximately 15% mismatches with M leprae. The Mexican family with leprosy involved the grandfather, mother, and 2 grandsons. The index was the oldest grandson, who manifested DLL and likely contracted the infection from his maternal grandfather approximately 13 years earlier. Family surveys diagnosed DLL in the index patient's mother and borderline leprosy in his brother; both were likely infected by the index patient. M lepromatosis was identified from archived biopsies from the index patient and his mother, while M leprae was excluded.

CONCLUSIONS

M lepromatosis is a significant cause of leprosy in Mexico and requires better surveillance and control.

Simultaneous detection and differentiation between Mycobacterium leprae and Mycobacterium lepromatosis using novel polymerase chain reaction primers

We have developed a polymerase chain reaction-based method to detect and distinguish Mycobacterium leprae and Mycobacterium lepromatosis using a single set of primers based on a 45-bp difference in the amplicon size of their rpoT gene. This method can also help in detecting the cases of co-infection in a single experiment.

Diagnostic Value of 16S Ribosomal RNA Gene Polymerase Chain Reaction/Sanger Sequencing in Clinical Practice

BACKGROUND

Accurate microbiologic diagnosis is important for appropriate management of infectious diseases. Sequencing-based molecular diagnostics are increasingly used for precision diagnosis of infections. However, their clinical utility is unclear.

METHODS

We conducted a retrospective analysis of specimens that underwent 16S ribosomal RNA (rRNA) gene polymerase chain reaction (PCR) followed by Sanger sequencing at our institution from April 2017 through March 2019.

RESULTS

A total of 566 specimens obtained from 460 patients were studied. Patients were considered clinically infected or noninfected based on final diagnosis and management. In 17% of patients, 16S rRNA PCR/sequencing was positive and in 5% of patients, this test led to an impact on clinical care. In comparison, bacterial cultures were positive in 21% of patients. Specimens with a positive Gram stain had 12 times greater odds of having a positive molecular result than those with a negative Gram stain (95% confidence interval for odds ratio, 5.2-31.4). Overall, PCR positivity was higher in cardiovascular specimens (37%) obtained from clinically infected patients, with bacterial cultures being more likely to be positive for musculoskeletal specimens (P < .001). 16S rRNA PCR/sequencing identified a probable pathogen in 10% culture-negative specimens.

CONCLUSION

16S rRNA PCR/sequencing can play a role in the diagnostic evaluation of patients with culture-negative infections, especially those with cardiovascular infections.

Mycobacterium lepromatosis as a Second Agent of Hansen's Disease

Mycobacterium lepromatosis was identified as a new species and second causal agent of Hansen's disease (HD, or leprosy) in 2008, 150years after the disease was first attributed to Mycobacterium leprae. M. lepromatosis has been implicated in a small number of HD cases, and clinical aspects of HD caused by M. lepromatosis are poorly characterized. HD is a recognized zoonosis through transmission of M. leprae from armadillos, but the role of M. lepromatosis as a zoonotic agent of HD is unknown. M. lepromatosis was initially associated with diffuse lepromatous leprosy, but subsequent case reports and surveys have linked it to other forms of HD. HD caused by M. lepromatosis has been reported from three endemic countries: Brazil, Myanmar, and Philippines, and three non-endemic countries: Mexico, Malaysia, and United States. Contact with armadillos in Mexico was mentioned in 2/21 M. lepromatosis HD case reports since 2008. M. lepromatosis in animals has been investigated only in non-endemic countries, in squirrels and chipmunks in Europe, white-throated woodrats in Mexico, and armadillos in the United States. To date, there have only been a small number of positive findings in Eurasian red squirrels in Britain and Ireland. A single study of environmental samples found no M. lepromatosis in soil from a Scottish red squirrel habitat. Future studies must focus on endemic countries to determine the true proportion of HD cases caused by M. lepromatosis, and whether viable M. lepromatosis occurs in non-human sources.

Isolation of Mycobacterium lepromatosis and Development of Molecular Diagnostic Assays to Distinguish Mycobacterium leprae and M. lepromatosis

BACKGROUND

Mycobacterium leprae was thought to be the exclusive causative agent of leprosy until Mycobacterium lepromatosis was identified in a rare form of leprosy known as diffuse lepromatous leprosy (DLL).

METHODS

We isolated M. lepromatosis from a patient with DLL and propagated it in athymic nude mouse footpads. Genomic analysis of this strain (NHDP-385) identified a unique repetitive element, RLPM, on which a specific real-time quantitative polymerase chain reaction assay was developed. The RLPM assay, and a previously developed RLEP quantitative polymerase chain reaction assay for M. leprae, were validated as clinical diagnostic assays according to Clinical Laboratory Improvement Amendments guidelines. We tested DNA from archived histological sections, patient specimens from the United States, Philippines, and Mexico, and US wild armadillos.

RESULTS

The limit of detection for the RLEP and RLPM assays is 30 M. leprae per specimen (0.76 bacilli per reaction; coefficient of variation, 0.65%-2.44%) and 122 M. lepromatosis per specimen (3.05 bacilli per reaction; 0.84%-2.9%), respectively. In histological sections (n = 10), 1 lepromatous leprosy (LL), 1 DLL, and 3 Lucio reactions contained M. lepromatosis; 2 LL and 2 Lucio reactions contained M. leprae; and 1 LL reaction contained both species. M. lepromatosis was detected in 3 of 218 US biopsy specimens (1.38%). All Philippines specimens (n = 180) were M. lepromatosis negative and M. leprae positive. Conversely, 15 of 47 Mexican specimens (31.91%) were positive for M. lepromatosis, 19 of 47 (40.43%) were positive for M. leprae, and 2 of 47 (4.26%) contained both organisms. All armadillos were M. lepromatosis negative.

CONCLUSIONS

The RLPM and RLEP assays will aid healthcare providers in the clinical diagnosis and surveillance of leprosy.

Molecular epidemiology of leprosy: An update

Molecular epidemiology investigations are notoriously challenging in the leprosy field mainly because the inherent characteristics of the disease as well as its yet uncultivated causative agents, Mycobacterium leprae and M. lepromatosis. Despite significant developments in understanding the biology of leprosy bacilli through genomic approaches, the exact mechanisms of transmission is still unclear and the factors underlying pathological variation of the disease in different patients remain as major gaps in our knowledge about leprosy. Despite these difficulties, the last two decades have seen the development of genotyping procedures based on PCR-sequencing of target loci as well as by the genome-wide analysis of an increasing number of geographically diverse isolates of leprosy bacilli. This has provided a foundation for molecular epidemiology studies that are bringing a better understanding of strain evolution associated with ancient human migrations, and phylogeographical insights about the spread of disease globally. This review discusses the advantages and drawbacks of the main tools available for molecular epidemiological investigations of leprosy and summarizes various methods ranging from PCR-based genotyping to genome-typing techniques. We also describe their main applications in analyzing the short-range and long-range transmission of the disease. Finally, we summarise the current gaps and challenges that remain in the field of molecular epidemiology of leprosy.

16S rRNA Gene PCR/Sequencing of Cerebrospinal Fluid in the Diagnosis of Post-operative Meningitis

INTRODUCTION

Post-operative meningitis (POM) is a life-threatening complication of neurosurgery. Diagnosis is often difficult due to pre-existing inflammation and antecedent antimicrobial use. Bacterial cerebrospinal fluid (CSF) cultures may reveal no growth, but empiric antibiotics are typically given due to the high morbidity and mortality associated with POM. 16S rRNA gene PCR/sequencing is a molecular methodology that can identify the presence of bacteria regardless of viability for culture.

CASE PRESENTATION

A patient presented with a rapid onset of fever associated with headache, neck pain, nausea and altered mental status 11 days after undergoing laser interstitial thermal therapy for treatment of recurrent astrocytoma at another hospital. Based on clinical presentation and imaging, POM was suspected, and empiric antibacterial therapy was started. Microbiological stains and cultures of CSF were negative. Due to persistent fevers, 16S rRNA gene PCR/sequencing was done on CSF; it detected a member of the order Enterobacteriales most closely resembling Serratia species. All antimicrobials were stopped except for cefepime, which was given for 2 weeks. The patient's mental status fully recovered.

CONCLUSION

The application of 16S rRNA gene PCR/sequencing in the setting of POM is of value by improving the quality of patient care and decreasing costs by antimicrobial de-escalation. Further studies regarding the positive and negative predictive values of this test are required.

Cutaneous leprosy in Central Florida man with significant armadillo exposure

Leprosy is a chronic infectious, granulomatous disease caused by the intracellular bacillus Mycobacterium leprae that infects macrophages and Schwann cells. While relatively rare in the USA, there is about 200 new cases of leprosy every year with the majority occurring in the southern parts of the country. It is believed to be linked to the region of the nine-banned armadillo in patients with no significant travel history outside of the country. In this case report, we encountered a 58-year-old Central Florida man that had extensive exposure to armadillos and presented with the typical symptoms of large erythaematous patches, numbness and peripheral nerve hypertrophy. Once diagnosed properly, patients are then reported to the National Hansen's Centre who provides the multidrug therapy for 12-24 months. Due to its rarity and its ability to mimic other more common ailments, leprosy should be included in the differential diagnosis in patients that have significant exposure to armadillos, live in the southern part of the country or have recently travelled to countries that have a high prevalence of leprosy.

Major risk factors for leprosy in a non-endemic area of the United States: A case series

Approximately 200 cases of leprosy are reported each year in the United States, and about 175 of the cases are diagnosed for the first time. Florida contributes a large number of reported cases each year and is showing an increasing incidence. Studies from other southern U.S. states demonstrate infection with the same strain of Mycobacterium leprae, confirming human armadillo exposure as the main risk factor. In contrast, cases from Florida show no clear risk factor. We present three cases (two foreign born and one autochthonous case) from Hillsborough county Florida, that were reported from this non-endemic area during the past five years. The first case was a 35-year-old male from Mexico, with history of exposure from a Haitian inmate, who presented with multiple erythematous non-tender cutaneous lesions and numbness in both hands. Biopsy confirmed borderline lepromatous leprosy. The second case was a 34-year-old male, from Florida who presented with sparse annular non-supporative lesions on left cheek with one-month duration and denied leprosy or armadillo exposure. Biopsy confirmed the diagnosis of borderline tuberculoid leprosy. The third case was a 38-year-old female, from Puerto Rico who presented with disseminated painless plaques, edema of the hands with numbness and paresthesia. She denied leprosy or armadillo exposure. The biopsy confirmed borderline lepromatous leprosy with erythema nodosum leprosum. Our case series demonstrates that a history of armadillo exposure is not always present. Other risk factors need to be considered when leprosy is a possible diagnosis in a patient.

Leprosy in a Midwestern Dermatology Clinic: Report of 9 Patients

OBJECTIVE

To describe the clinical features and epidemiology of leprosy in patients evaluated in a Midwestern dermatology clinic.

PATIENTS AND METHODS

We performed a retrospective review of clinical and laboratory data from patients with leprosy who were evaluated in the Department of Dermatology at Mayo Clinic in Rochester, Minnesota, from January 1, 1994, through December 31, 2017.

RESULTS

Nine patients, 7 male and 2 female, were identified, ranging in age from 15 to 63 years (mean age, 38 years). Six of the 9 patients (67%) were foreign-born: 3 from Oceania (2 from Micronesia and 1 from Guam), 1 from Southeast Asia (Indonesia), and 2 from Mexico. Three patients were born in the United States. All 9 patients presented with skin lesions (granulomatous histopathologic type), and 8 had neuropathy. Leprosy was multibacillary in 8 patients and paucibacillary in 1. Two patients experienced a type 1 treatment reaction, and 5 had type 2 reactions. Three of the 9 patients had speciation by polymerase chain reaction (Mycobacterium leprae in 2 and Mycobacterium lepromatosis in 1).

CONCLUSION

Despite its rarity in the United States, leprosy should be considered in the differential diagnosis when evaluating both foreign- and US-born patients with granulomatous dermatitis and peripheral neuropathy. Because M lepromatosis was not identified until 2008 and requires polymerase chain reaction for diagnosis, the incidence of this species among patients with leprosy diagnosed in earlier years is unknown.

Identification of Mycobacterium leprae and Mycobacterium lepromatosis in Formalin-Fixed and Paraffin-Embedded Skin Samples from Mexico

Background

The causative agents of leprosy are the well-known Mycobacterium leprae and the newly discovered Mycobacterium lepromatosis. This agent was found in 2008, and it was found to be the cause of diffuse lepromatous leprosy in two Mexican patients.

Objective

The objective of this work was to determine if M. leprae and M. lepromatosis were present in formalin-fixed and paraffin-embedded skin samples from cases from different regions in Mexico.

Methods

A total of 41 skin samples were obtained from 11 states of Mexico. All patients' samples were diagnosed by clinical and histopathological analyses. Total DNA was isolated using a Qiagen-DNeasy blood and tissue kit and molecular identification was achieved by two semi-nested polymerase chain reactions.

Results

The 41 patient included 33 samples from men and 8 samples from women; 29 samples were polymerase chain reaction (PCR)-positive to Mycobacterium and 12 samples were PCR-negative. From those 29 samples, 13 were PCR-positive to M. leprae, 8 to M. lepromatosis and 8 were positive to both species. The histopathological diagnosis included; Nodular lepromatous leprosy (NLL); Diffuse lepromatous leprosy (DLL); and Borderline leprosy (BL). The 29 PCR-positive samples were classified as follow: 14 NLL, 4 DLL, and 11 BL. In the 12 samples negative to Mycobacterium, 7 showed the NLL, 2 DLL and 3 BL.

Conclusion

These findings add evidence to the M. leprae and M. lepromatous distribution, clinical forms and participation of dual infections in Mexico.