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PubMed1993

Hantavirus in the southwestern United States: epidemiology of an emerging pathogen.

In May of this year, an outbreak of sudden, unexplained, and highly fatal respiratory illness of unknown etiology was identified in the four-corners region of the southwestern United States. Within 3 weeks after the collaborative response launched by the state and local health agencies in the affected area, laboratory studies from the federal Centers for Disease Control and Prevention suggested that an acute infection with a previously unrecognized Hantavirus species was responsible for the reported cluster of cases. The hantavirus associated with this outbreak has since been isolated in tissue culture, and diagnostic test systems specific for the newly identified hantavirus have been developed. This article summarizes the history of the outbreak as experienced by investigators from the Arizona Department of Health Services and reviews the epidemiologic and clinical aspects of both the current epidemic and hantaviruses in general. The sudden occurrence of acute illnesses in the Southwest due to a previously unrecognized hantavirus reaffirms that the potential for the emergence of new infectious diseases exists at any place or time in the United States. The response to the outbreak also illustrates how community clinicians and federal, state, and local health agencies work together to promptly identify the emergence of new disease threats, rapidly determine new etiologic agents, and develop and swiftly implement appropriate disease prevention and control strategies.

Adult↗
PubMed2002

Relatively alcohol-resistant mycobacteria are emerging pathogens in patients receiving acupuncture treatment.

Acupuncture has been gaining popularity as a form of alternative medicine. In the past, only blood-borne viruses and anecdotal reports of bacterial infections have been associated with acupuncture. We report on four patients with mycobacterial infections complicating acupuncture who were encountered in a 2-year period. All had clinical and/or radiological lesions at acupuncture point- and meridian-specific locations. There was no other history of trauma or other clinical foci of infections, and the chest radiographs were normal. Histological studies of biopsy specimens of all four patients showed changes compatible with chronic inflammation, with granulomatous inflammation present in three patients and acid-fast bacilli present in two. Conventional biochemical tests and whole-cell fatty acid analysis for identification were inconclusive for all four nonpigmented mycobacteria recovered from tissue biopsies. 16S rRNA gene sequencing showed that the strains from two patients were Mycobacterium chelonae and that those from the other two were Mycobacterium nonchromogenicum. Alcohol resistance assay using the quantitative suspension test revealed that all four strains showed prolonged survival in 75% alcohol compared to other skin flora. Mycobacterial infections transmitted by acupuncture are an emerging problem. A high index of suspicion is essential to recognize this clinical syndrome, and strict implementation of proper infection control guidelines for acupuncture is mandatory.

2-Propanol↗
PubMed2004

Mycobacterium celatum, an emerging pathogen and cause of false positive amplified Mycobacterium tuberculosis direct test.

Mycobacterium celatum is a recently described organism. Herein we describe a case of M. celatum lymphadenitis in an immunocompetent child and the first reported case of a M. celatum infection (lung abscess) in a transplant recipient. A literature review identified 19 other cases of M. celatum infection. Fifteen occurred in patients with the acquired immunodeficiency syndrome. Of these, nine were disseminated and six were localized (primarily to the lungs). The remaining 4 patients were immunocompetent and had localized infection (pneumonitis or lymphadenitis). Diagnosis of M. celatum infection can be challenging as M. celatum can cause false-positive results with the current version of the Amplified Mycobacterium tuberculosis Direct Test (Gen-Probe, San Diego, CA.). Definitive identification is available by DNA sequencing or high-performance liquid chromatography. M. celatum can cause infection in immunocompromised and immunocompetent hosts.

AIDS-Related Opportunistic Infections↗
PubMedDate not supplied

[Epidemiology and ecology of dermatophytoses in the City of Fortaleza: Trichophyton tonsurans as important emerging pathogen of Tinea capitis].

Dermatophytosis is the most common skin infectious disturbance in the world. In this research 2,297 patients were evaluated with suspected clinical lesions of dermatophytosis. It was observed that, 534 (23.2%) patients tested positive for dermatophytes. T. rubrum was the most prevalent specie (49.6%; p < or = 0.05), followed by T. tonsurans (34.4%), M. canis (7%) and T. mentagrophytes (6.2%). When the species isolated was correlated with the respective anatomical localization, it was observed that T. tonsurans was the most frequent isolated in scalp lesions (73.9%; p < or = 0.01). On the other hand, T. rubrum was the main specie involved in body lesions (72.8%; p < or = 0.05). Therefore, in scalp infections it was observed that, there was an absolute prevalence of T. tonsurans. This evidence is different from the statistical data collected in the southeast and south of Brazil, as well as from other areas of the world, which still show M. canis as the most frequent microorganism isolated in Tinea capitis.

Adolescent↗
PubMed2003

Community-acquired methicillin-resistant Staphylococcus aureus: an emerging pathogen.

The prevalence of MRSA in the nosocomial setting has been well studied, and its control remains a challenge for infection control professionals. Complicating this problem is the increasing number of reports on the spread of community-acquired MRSA (CA-MRSA). CA-MRSA strains differ from hospital-acquired MRSA (HA-MRSA) strains in that they are generally susceptible to most antibiotics. These strains share the presence of staphylococcal cassette chromosome mec (SCCmec) type IV in their genomes, are frequently virulent, and predominantly cause skin and soft tissue infections. The genome sequence of the prototypic CA-MRSA strain, MW2, revealed the presence of additional virulence factors not commonly present in other S. aureus strains. We determined the genetic relatedness of 30 geographically diverse CA-MRSA isolates clustered based on SCCmec type IV by sequence analysis of the polymorphic repeat region of the protein A gene (spa typing). These results indicated that most strains shared a common spa type (131), identical to MW2. Because this group tends to infect healthy individuals with no known risk factors for nosocomial acquisition of MRSA, we refer to it as CA-MRSA without risk factors. A second group, CA-MRSA with risk factors, consists of two related genotypes, spa types 1 and 7, which differ by one nucleotide change. These strains have caused severe infections in HIV-positive patients in Los Angeles and New York. Although CA-MRSA strains share genetic determinants, they are not clonal but rather are derived from different genetic backgrounds. The genetic characteristics and the epidemiology of CA-MRSA with and without risk factors are discussed.

Communicable Diseases, Emerging↗
PubMed2006

In vitro activity and synergism of amphotericin B, azoles and cationic antimicrobials against the emerging pathogen Trichoderma spp.

OBJECTIVES: The uncommon fungal pathogen Trichoderma shows increasing medical importance particularly in immunocompromised patients. Despite systemic antifungal therapy, prognosis of Trichoderma infection is poor regardless of the type of infection and the therapy used. The aim of the present study was to evaluate the in vitro activity and synergism of double antifungal combinations including amphotericin B, voriconazole, fluconazole, chlorhexidine digluconate and Akacid plus against 15 isolates of Trichoderma longibrachiatum and 1 isolate of Trichoderma harzianum. METHODS: Individual MICs were determined by using broth microdilution method following the NCCLS M38-A guidelines with standard RPMI 1640 broth. Synergy tests were performed using the chequerboard method. RESULTS: All clinical Trichoderma strains showed reduced susceptibility to fluconazole (MICs>or=64 mg/L) and amphotericin B (MICs=2 mg/L), whereas lower MICs of 0.5-1 mg/L were detected for voriconazole. Akacid plus reached the lowest MIC values in a range of 0.06-0.5 mg/L, 4- to 32-fold higher MICs were found for chlorhexidine. No antagonism was observed for any of the antifungal combinations tested. Interaction of amphotericin B and azoles was indifferent (fractional inhibitory concentration index, FICI 2-4). The combination of one azole and one cationic biocide showed different degree of synergism (FICI 0.07-2.03). Interaction of Akacid plus and chlorhexidine resulted in synergism for each Trichoderma isolate (FICI-range 0.05-0.5). CONCLUSIONS: These results demonstrate no interaction between antifungals and some degree of synergism between azoles and cationic antimicrobials against Trichoderma spp.

Amphotericin B↗
PubMed1999

The new herpesviruses: emerging pathogens of dermatological interest.

OBJECTIVES: To discuss the current knowledge of 3 recently discovered human herpesviruses (HHV-6, HHV-7, and HHV-8), and to provide a dermatological point of view. DATA SOURCES: References identified from bibliographies of pertinent articles in the English language. STUDY SELECTION AND DATA EXTRACTION: Articles were selected according to their impact factor and the interest for dermatologists. DATA SYNTHESIS: As the other members of the family Herpesviridae, HHV-6, HHV-7, and HHV-8 may cause a primary infection, establish latent infection in a specific set of cells of their host, and then reactivate if conditions of altered immunity develop. The main pathological conditions associated with them are discussed. CONCLUSIONS: Human herpesvirus 6, HHV-7, and HHV-8 have provided new insights in some dermatological diseases. Although new studies are needed, they may have a profound impact on dermatology in the years to come.

Exanthema Subitum↗
PubMed2006

Parvovirus B19: a new emerging pathogenic agent of inflammatory cardiomyopathy.

The human parvovirus B19 (PVB19), an erythrovirus causing diverse clinical manifestations ranging from asymptomatic or mild to more severe outcomes such as hydrops fetalis, is the only currently known human pathogenic parvovirus. Recently, PVB19 has been identified as a causative agent of pediatric and adult inflammatory cardiac diseases. The first hints for a possible etiopathogenetic role of the PVB19 infection and the development of cardiac dysfunction were demonstrated by molecular biology methods such as in situ hybridization (ISH) and polymerase chain reaction (PCR). In this regard, PVB19-associated inflammatory cardiomyopathy is characterized by infection of endothelial cells of small intracardiac arterioles and venules, which may be associated with endothelial dysfunction, impairment of myocardial microcirculation, and penetration of inflammatory cells in the myocardium.

Cardiomyopathies↗
PubMed1989

Emerging pathogens in nosocomial pneumonia.

The organisms responsible for nosocomial pneumonia are continuously evolving. Gram-negative bacilli have become the most common etiologic agents over the past 20 years, and with this evolution has come a better understanding of the pathogenesis of gram-negative bacillary pneumonia. Some gram-positive cocci, such as enterococci, group B beta hemolytic streptococci and methicillin-resistant Staphylococcus aureus, haven taken on new significance in nosocomial respiratory infections. Streptococcus pneumoniae, nontypeable Haemophilus influenzae and Branhamella catarrhalis are increasingly reported in hospitalized patients with chronic lung disease. Etiologic agents will change as new antibiotics are introduced. A better understanding of etiologic agents and their pathogens may be the best tool toward preventing hospital-acquired pneumonia.

Cross Infection↗
PubMed1994

Mycobacterium genavense: an emerging pathogen.

Disseminated mycobacterial infection, often due to Mycobacterium avium complex, occurs frequently in patients with AIDS. More recently, a newly identified mycobacterium, Mycobacterium genavense, has been repeatedly isolated from AIDS patients. Mycobacterium genavense has unusual fastidious growth requirements and shows poor and variable growth in vitro. Molecular biology techniques are necessary for accurate diagnosis of infection and have established Mycobacterium genavense to be a definite cause of disseminated mycobacterial infection in immunosuppressed patients. The clinical manifestations of infection caused by Mycobacterium genavense are similar to those of infection caused by Mycobacterium avium complex organisms. This similarity in clinical presentation and inherent difficulties in applying standard, culture-based techniques for detection and identification of mycobacteria have probably led to underestimation of the prevalence of disseminated Mycobacterium genavense infection in patients with AIDS.

AIDS-Related Opportunistic Infections↗
PubMed2002

Human herpesvirus 6 and human herpesvirus 7: emerging pathogens in transplant patients.

Human herpesvirus 6 (HHV-6) and HHV-7 are two recently identified beta-herpesviruses, genetically related to human cytomegalovirus (CMV). Infection with both viruses is common worldwide with rates of seropositivity in adults over 90%. Infection with both viruses usually occurs in early childhood. In this age group HHV-6 is a cause of febrile illness including exanthem subitum, and likewise, primary HHV-7 infection has been associated with febrile illness. Similar to the other human herpesviruses, in particular CMV, the viruses have the potential for enhanced pathogenicity in the immunocompromised host. Active infection with both viruses is common following bone marrow or solid organ transplantation, most likely through reactivation of recipient's virus or re-infection considering their high prevalence in the population. Both viruses can be detected by PCR in the peripheral blood of healthy individuals and although the significance of blood-borne transmission is not clear, a preliminary study suggested that it was not significant for HHV-6. However, there is growing evidence that these viruses may be medically important in the post-transplant period. In bone marrow transplant patients HHV-6 has been associated with a range of clinical disease including encephalitis, interstitial pneumonitis, early and late graft failure and bone marrow suppression. There is also growing evidence for potential interactions among the beta-herpesviruses in liver and renal transplant patients. HHV-6 infection has been associated with an increased risk of developing CMV disease and opportunistic infections and HHV-7 infection has also been linked to an increased risk of CMV disease.

Herpesviridae Infections↗
PubMed1995

Emerging pathogens: Aeromonas spp.

Aeromonas spp. are Gram-negative rods of the family Vibrionaceae. They are normal water inhabitants and are part of the regular flora of poiquilotherm and homeotherm animals. They can be isolated from many foodstuffs (green vegetables, raw milk, ice cream, meat and seafood). Mesophilic Aeromonas spp. have been classified following the AeroKey II system (Altwegg et al., 1990; Carnahan et al., 1991). The major human diseases caused by Aeromonas spp. can be classified in two major groups: septicemia (mainly by strains of A. veronii subsp. sobria and A. hydrophila), and gastroenteritis (any mesophilic Aeromonas spp. but principally A. hydrophila and A. veronii). Most epidemiological studies have shown Aeromonas spp. in stools to be more often associated with diarrhea than with the carrier state; an association with the consumption of untreated water was also conspicuous. Acute self-limited diarrhea is more frequent in young children, in older patients chronic enterocolitis may also be observed. Fever, vomiting, and fecal leukocytes or erythrocytes (colitis) may be present (Janda, 1991). The main putative virulence factors are: exotoxins, endotoxin (LPS), presence of S-layers, fimbriae or adhesins and the capacity to form capsules.

Aeromonas↗
PubMed2004

Characterization of the in vitro antimycotic activity of a novel killer protein from Williopsis saturnus DBVPG 4561 against emerging pathogenic yeasts.

A novel killer toxin, labelled as KT4561, secreted by Williopsis saturnus DBVPG 4561, was found to possess a wide antimycotic activity against strains of Candida glabrata, Issatchenkia orientalis and Pichia guillermondii. KT4561 was precipitated by ethanol and purified by ion-exchange chromatography. The active protein migrated as a single band in SDS-PAGE and was characterized by a molecular weight of approximately 62 kDa. Purified KT4561 was active across wide ranges of temperature (5-45 degrees C) and pH (4.5-8.0) and displayed a rapid decrease in viability of yeast cells after 4-8 h. The in vitro activity of KT4561 against 102 yeast isolates (79% of clinical origin) was determined: MIC(50) and MIC(90) of strains were 0.08 and 0.15 microg/ml for C. glabrata, 0.03 and 0.23 microg/ml for I. orientalis and 1.50 and 2.25 microg/ml for P. guilliermondii. Comparative susceptibility tests showed that a high number of strains used in the present study were insensitive to selected azole and polyene antibiotics. The present study demonstrated the potential of KT4561 to be applied as novel control agent against pathogenic yeasts.

Antifungal Agents↗
PubMed2006

Mycobacterium heckeshornense: an emerging pathogen responsible for a recurrent lung infection.

Mycobacterium heckeshornense was responsible for a severe, recurrent and chronic pulmonary infection in an immunocompetent 65-year-old woman. The pathogen, initially identified as Mycobacterium xenopi and considered as a contaminant, led to a delayed adapted antimicrobial treatment. Although M. heckeshornense is phenotypically closely related to M. xenopi, its pathogenicity is noticeably higher. Accurate molecular diagnosis methods and treatment guidelines are needed to improve the management of patients infected by this uncommon pathogen.

Aged↗