Paracoccidioidal Infection in HIV Patients at an Endemic Area of Paracoccidioidomycosis in Brazil

The association between paracoccidioidomycosis (PCM) and AIDS is relatively rare in contrast to the higher incidence of other systemic mycosis. The explanation may be that AIDS is still predominantly an urban disease, and the PCM is endemic in Latin American rural areas. The aim of this study was to detect the prevalence of Paracoccidioides brasiliensis infection in HIV-positive patients at an endemic area of paracoccidioidomycosis in Brazil. Skin test with purified 43 kD glycoprotein (gp43) was performed in 90 HIV/AIDS patients. The prevalence found was 12.2% and it may be even greater, considering that HIV/AIDS patients may not respond to the intradermal test, which depends on cellular immunity for its positivity.     

Low-Density Granulocytes Are Elevated in Mycobacterial Infection and Associated with the Severity of Tuberculosis

Tuberculosis remains a global health problem caused by infection with Mycobacterium tuberculosis. Numerous studies have established a close correlation between the development of tuberculosis and the roles of neutrophils. Recently, a distinct population of CD15⁺ granulocytes was found to be present in the peripheral blood mononuclear cell (PBMC) fraction in humans. This population of granulocytes, termed low-density granulocytes (LDGs), was reported to be elevated and associated with disease activity or severity in a number of different conditions including SLE, asthma and HIV infection. However, both the frequency and clinical significance of LDGs associated with tuberculosis are unclear. Here we determined LDG levels and made comparisons between subjects with active pulmonary tuberculosis (PTB) and healthy controls, between PTB patients with mild-to-moderate disease and patients with advanced disease, and among PTB patients following anti-tuberculous therapy of varying durations. The direct correlation between M. tuberculosis infection and LDG levels was confirmed by in vitro infection of whole peripheral blood and isolated granulocytes with mycobacteria. Our results demonstrated that PBMCs in PTB patients contained significantly elevated percentages of LDGs compared with control subjects. LDGs in tuberculosis expressed higher levels of activation markers compared to normal-density granulocytes (NDGs). M. tuberculosis induced the generation of LDGs in both whole blood and isolated NDGs from control subjects, which suggests that LDGs associated with M. tuberculosis infection are likely to originate from in situ activation. Furthermore, our results revealed that the frequency of LDGs is associated with the severity of tuberculosis.     

Rheumatoid Arthritis Increases the Risk of Nontuberculosis Mycobacterial Disease and Active Pulmonary Tuberculosis

Background

Few studies have examined the association of rheumatoid arthritis (RA) with nontuberculosis mycobacterium (NTM) disease and pulmonary tuberculosis (PTB).

Methods

We identified 29 131 patients with RA from the catastrophic illness registry who were diagnosed from 1998–2008; 116 524 patients without RA from inpatient data files were randomly frequency matched according to sex, age, and index year and used as a comparison group. Both groups were followed-up until the end of 2010 to measure the incidence of NTM disease and active PTB. We analyzed the risk of NTM disease and active PTB using the Cox proportional hazards regression models, controlling for sex, age, and Charlson comorbidity index (CCI).

Results

The incidence of NTM disease was 4.22 times greater in the RA group than in the non-RA group (1.91 vs 0.45 per 10,000 person-years). The incidence of PTB was 2.99 times greater in the RA group than in the non-RA group (25.3 vs 8.46 per 10,000 person-years). After adjusting for age, sex, and CCI, the adjusted hazard ratios (HRs) of NTM disease and active PTB for the RA group were 4.17 (95% CI = 2.61–6.65) and 2.87 (95% CI = 2.55–3.23), respectively, compared with the non-RA group. In the first 2 years of follow-up, the RA group yielded corresponding adjusted HRs of 4.98 and 3.39 compared with the non-RA group. The follow-up time-specific RA group to the non-RA group HR of both the NTM disease and active PTB varied.

Conclusion

This study can serve as a reference for clinical physicians to increase awareness regarding the detection of NTM disease and active PTB in RA patients among the any stage of the clinical course even without CCI.     

Occurrence of Nontuberculous Mycobacteria in Environmental Samples

Nontuberculous mycobacteria (NTM) are a major cause of opportunistic infection in immunocompromised hosts. Because there is no evidence of person-to-person transmission and NTM have been found in drinking water, the environment is considered a likely source of infection. In this study the widespread occurrence of NTM was examined in drinking water, bottled water, and ice samples. A total of 139 samples were examined for NTM by a membrane filtration culture technique followed by PCR amplification and 16S rRNA sequence determination to identify the isolates. NTM were not detected in bottled water or cisterns but were detected in 54% of the ice samples and 35% of the public drinking-water samples from 21 states. The most frequently occurring isolate was M. mucogenicum (formerly referred to as an M. chelonae-like organism).     

Blood Neutrophil Counts in HIV-Infected Patients with Pulmonary Tuberculosis: Association with Sputum Mycobacterial Load

Background

Increasing evidence suggests that neutrophils play a role in the host response to Mycobacterium tuberculosis. We determined whether neutrophil counts in peripheral blood are associated with tuberculosis (TB) and with mycobacterial load in sputum in HIV-infected patients.

Methodology/Principal Findings

Adults enrolling in an antiretroviral treatment (ART) clinic in a Cape Town township were screened for TB regardless of symptoms. Paired sputum samples were examined using liquid culture, fluorescence microscopy, and the Xpert MTB/RIF assay. Absolute neutrophil counts (ANC) were measured in blood samples. Of 602 HIV-infected patients screened, 523 produced one or more sputum samples and had complete results available for analysis. Among these 523 patients, the median CD4 count was 169×10⁹/L (IQR, 96–232) and median ANC was 2.6×10⁹/L (IQR, 1.9–3.6). Culture-positive pulmonary tuberculosis was diagnosed in 89 patients. Patients with TB had a median ANC of 3.4×10⁹/L (IQR, 2.4–5.1) compared to 2.5×10⁹/L (IQR, 1.8–3.4) among those who were culture negative (p<0.0001). In multivariable analyses, having pulmonary TB was associated with an adjusted risk ratio (aRR) of 2.6 (95%CI, 1.5–4.5) for having an ANC level that exceeded the median value (ANC ≥2.6×10⁹/L; p = 0.0006) and an aRR of 6.8 (95%CI, 2.3–20.4) for having neutrophilia defined by a neutrophil count exceeding the upper limit of the normal range (ANC >7.5×10⁹/L; p = 0.0005). Patients were then classified into four mutually exclusive groups with increasing sputum mycobacterial load as defined by the results of culture, Xpert MTB/RIF and sputum smear microscopy. Multivariable analyses demonstrated that increasing sputum mycobacterial load was positively associated with blood ANC ≥2.6×10⁹/L and with neutrophilia.

Conclusions/Significance

Increased blood neutrophil counts were independently associated with pulmonary TB and sputum mycobacterial burden in this HIV-infected patient group. This observation supports the growing body of literature regarding the potential role for neutrophils in the host response to TB.     

Monthly Occurrence of Vectors and Reservoir Rodents of Scrub Typhus in an Endemic Area of Jeollanam-do, Korea

Monthly surveys were conducted to investigate the occurrence of chigger mites and seroprevalence of scrub typhus among small mammals in Jeollanam-do, the southwestern part of Korea, from November 2006 through October 2007. Fifty-eight small mammals, including 57 Apodemus agrarius (98.3%) and 1 Crocidura lasiura (1.7%), were captured, and a total of 4,675 chigger mites representing 4 genera and 8 species were collected from them. The chigger infestation rate among small mammals was 69.0%. The most predominant species in A. agrarius was Leptotrombidium scutellare (54.0%), followed by Leptotrombidium pallidum (39.4%), Leptotrombidium orientale (4.4%), Leptotrombidium palpale (1.1%), Neotrombicula tamiyai (0.6%), Eushoengastia koreaensis (0.3%), Neotrombicula gardellai (0.3%), and Cheladonta ikaoensis (<0.1%). The chigger index of A. agrarius was the highest in October (740.0), followed by November (242.0), September (134.6), March (98.3), February (38.2), January (35.3), December (34.5), April (30.8), and May (1.7). The average antibody positive rate of scrub typhus in wild rodents was 50.0%. The seropositive rates were high in October (100.0%) and November (83.3%), whereas those in other months were relatively low (28.6-57.1%). The chigger index of L. scutellare rapidly increased in September to form an acuminate peak in October, followed by a gradual decline. These results suggest that the outbreak of scrub typhus in the southwestern part of Korean peninsula is mostly due to L. scutellare.     

Relationships between Mycobacterium Isolates from Patients with Pulmonary Mycobacterial Infection and Potting Soils

High numbers of mycobacteria, including known pathogenic species such as Mycobacterium avium, Mycobacterium intracellulare, and Mycobacterium chelonae, were recovered from aerosols produced by pouring commercial potting soil products and potting soil samples provided by patients with pulmonary mycobacterial infections. The dominant mycobacteria in the soil samples corresponded to the dominant species implicated clinically. Profiles of large restriction fragments obtained by pulsed-field gel electrophoresis demonstrated a closely related pair of M. avium isolates recovered from a patient and from that patient's own potting soil. Thus, potting soils are potential sources of infection by environmental mycobacteria. Use of dust-excluding masks should be considered during potting or other activities that generate aerosol with soil.     

Delivery of Aerosolized Liposomal Amikacin as a Novel Approach for the Treatment of Nontuberculous Mycobacteria in an Experimental Model of Pulmonary Infection

Pulmonary infections caused by nontuberculous mycobacteria (NTM) are an increasing problem in individuals with chronic lung conditions and current therapies are lacking. We investigated the activity of liposomal amikacin for inhalation (LAI) against NTM in vitro as well as in a murine model of respiratory infection. Macrophage monolayers were infected with three strains of Mycobacterium avium, two strains of Mycobacterium abscessus, and exposed to LAI or free amikacin for 4 days before enumerating bacterial survival. Respiratory infection was established in mice by intranasal inoculation with M. avium and allowing three weeks for the infection to progress. Three different regimens of inhaled LAI were compared to inhaled saline and parenterally administered free amikacin over a 28 day period. Bacteria recovered from the mice were analyzed for acquired resistance to amikacin. In vitro, liposomal amikacin for inhalation was more effective than free amikacin in eliminating both intracellular M. avium and M. abscessus. In vivo, inhaled LAI demonstrated similar effectiveness to a ∼25% higher total dose of parenterally administered amikacin at reducing M. avium in the lungs when compared to inhaled saline. Additionally, there was no acquired resistance to amikacin observed after the treatment regimen. The data suggest that LAI has the potential to be an effective therapy against NTM respiratory infections in humans.     

Sero-Epidemiology of Lyme Disease in an Endemic Area in China

A sero-epidemiological investigation on Lyme disease was carried out in a forestry center of Hailin County, Heilongjiang Province, China. A total of 381 participants including forestry workers and their dependents completed questionnaires and had blood samples taken for detection of antibody against Borrelia burgdorferi by indirect immunofluorescent assay. Of 381 participants, 250 (65.6%) had a history of tick bites between May and July, 1987, and 379 (99.5%) at some time in the past, 56 (14.7%) developed erythema migrans at the site of tick attachment, 138 (36.2%) had late manifestations of Lyme disease, and 101 (26.2%) were seropositive. There was a significant difference in the seropositive rate between the persons with tick bites and those without tick bites in 1987 (P<0.01). The titers in the older age group (over 30) were slightly higher than those of the younger age group (under 30). No relationship between the prevalence of Lyme manifestations by tick bites and the result of serological test was observed. Further investigations are necessary to assess the actual prevalence and incidence of infections using antigen of Lyme disease borreliae isolated in China.     

Surveillance of Tuberculosis in Taipei: The Influence of Nontuberculous Mycobacteria

Background

Notification of tuberculosis (TB) but not nontuberculous mycobacteria (NTM) is mandatory in Taiwan. Partly due to the strict regulation on TB notification, several patients infected with NTM were notified as TB cases. Notification of patients infected with NTM as TB cases can trigger public health actions and impose additional burdens on the public health system. We conducted a study to assess the influence of NTM infection on surveillance of TB in Taipei.

Methodology/Principal Findings

The study population included all individuals with a positive culture for Mycobacterium who were citizens of Taipei City and notified as TB cases in the calendar years 2007–2010. Of the 4216 notified culture-positive tuberculosis (TB) cases, 894 (21.2%) were infected with NTM. The average annual reported case rate of infection with NTM was 8.6 (95% confidence interval 7.7–9.4) per 100,000 people. The reported case rate of NTM increased with age in both males and females. The proportion of reported TB cases infected with NTM was significantly higher in females than in males (27.6% vs 17.8%, adjusted OR (adjOR) 1.93, 95% confidence interval (CI) 1.63–2.28); in smear-positive than in smear-negative (23.1% vs 19.2%, adjOR 1.26, 95% CI 1.08–1.47); and in previously treated cases than in new cases (35.7% vs 19.1%, adjOR 2.30, 95% CI 1.88–2.82). The most frequent species was M. avium complex (32.4%), followed by M. chelonae complex (17.6%), M. fortuitum complex (17.0%) and M. kansasii (9.8%). Of the 890 notified NTM cases assessed, 703 (79.0%) were treated with anti-TB drugs, and 730 (82.0%) were de-notified.

Conclusions/Significance

The influence of NTM on surveillance of TB in Taipei was substantial. Health authorities should take action to ensure that nucleic acid amplification tests are performed in all smear-positive cases in a timely manner to reduce the misdiagnosis of patients infected with NTM as TB cases.     

Coincident Helminth Infection Modulates Systemic Inflammation and Immune Activation in Active Pulmonary Tuberculosis

Background

Helminth infections are known to modulate innate and adaptive immune responses in active and latent tuberculosis (TB). However, the role of helminth infections in modulating responses associated with inflammation and immune activation (reflecting disease activity and/or severity) in TB is not known.

Methodology

We measured markers of inflammation and immune activation in active pulmonary TB individuals (ATB) with co-incidental Strongyloides stercoralis (Ss) infection. These included systemic levels of acute phase proteins, matrix metalloproteinases and their endogenous inhibitors and immune activation markers. As a control, we measured the systemic levels of the same molecules in TB-uninfected individuals (NTB) with or without Ss infection.

Principal Findings

Our data confirm that ATB is associated with elevated levels of the various measured molecules when compared to those seen in NTB. Our data also reveal that co-incident Ss infection in ATB individuals is associated with significantly decreased circulating levels of acute phase proteins, matrix metalloproteinases, tissue inhibitors of matrix metalloproteinases as well as the systemic immune activation markers, sCD14 and sCD163. These changes are specific to ATB since they are absent in NTB individuals with Ss infection.

Conclusions

Our data therefore reveal a profound effect of Ss infection on the markers associated with TB disease activity and severity and indicate that co-incidental helminth infections might dampen the severity of TB disease.     

Rapid Detection and Identification of Nontuberculous Mycobacterial Pathogens in Fish by Using High-Resolution Melting Analysis

Mycobacterial infections in fish are commonly referred to as piscine mycobacteriosis, irrespectively of the specific identity of the causal organism. They usually cause a chronic disease and sometimes may result in high mortalities and severe economic losses. Nearly 20 species of Mycobacterium have been reported to infect fish. Among them, Mycobacterium marinum, M. fortuitum, and M. chelonae are generally considered the major agents responsible for fish mycobacteriosis. As no quick and inexpensive diagnostic test exists, we tested the potential of high-resolution melting analysis (HRMA) to rapidly identify and differentiate several Mycobacterium species involved in fish infections. By analyzing both the melting temperature and melting profile of the 16S-23S rRNA internal transcribed spacer (ITS), we were able to discriminate 12 different species simultaneously. Sensitivity tests conducted on purified M. marinum and M. fortuitum DNA revealed a limit of detection of 10 genome equivalents per reaction. The primers used in this procedure did not lead to any amplification signal with 16 control non-Mycobacterium species, thereby demonstrating their specificity for the genus Mycobacterium.