RESUMO
HIV elite controllers represent a remarkable minority of patients who maintain normal CD4+ T-cell counts and low or undetectable viral loads for decades in the absence of antiretroviral therapy. To examine the possible contribution of virus attenuation to elite control, we obtained a primary HIV-1 isolate from an elite controller who had been infected for 19 years, the last 10 of which were in the absence of antiretroviral therapy. Full-length sequencing of this isolate revealed a highly unusual V1 domain in Envelope (Env). The V1 domain in this HIV-1 strain was 49 amino acids, placing it in the top 1% of lengths among the 6,112 Env sequences in the Los Alamos National Laboratory online database. Furthermore, it included two additional N-glycosylation sites and a pair of cysteines suggestive of an extra disulfide loop. Virus with this Env retained good infectivity and replicative capacity; however, analysis of recombinant viruses suggested that other sequences in Env were adapted to accommodate the unusual V1 domain. While the long V1 domain did not confer resistance to neutralization by monoclonal antibodies of the V1/V2-glycan-dependent class, it did confer resistance to neutralization by monoclonal antibodies of the V3-glycan-dependent class. Our findings support results in the literature that suggest a role for long V1 regions in shielding HIV-1 from recognition by V3-directed broadly neutralizing antibodies. In the case of the elite controller described here, it seems likely that selective pressures from the humoral immune system were responsible for driving the highly unusual polymorphisms present in this HIV-1 Envelope.IMPORTANCE Elite controllers have long provided an avenue for researchers to reveal mechanisms underlying control of HIV-1. While the role of host genetic factors in facilitating elite control is well known, the possibility of infection by attenuated strains of HIV-1 has been much less studied. Here we describe an unusual viral feature found in an elite controller of HIV-1 infection and demonstrate its role in conferring escape from monoclonal antibodies of the V3-glycan class. Our results suggest that extreme variation may be needed by HIV-1 to escape neutralization by some antibody specificities.
Assuntos
Proteína gp120 do Envelope de HIV/genética , HIV-1/genética , Fragmentos de Peptídeos/genética , Produtos do Gene env do Vírus da Imunodeficiência Humana/genética , Sequência de Aminoácidos , Anticorpos Monoclonais/metabolismo , Anticorpos Neutralizantes/imunologia , Epitopos/imunologia , Glicosilação , Anticorpos Anti-HIV/imunologia , Proteína gp120 do Envelope de HIV/imunologia , Proteína gp120 do Envelope de HIV/metabolismo , Infecções por HIV/virologia , HIV-1/imunologia , HIV-1/patogenicidade , Humanos , Evasão da Resposta Imune/imunologia , Testes de Neutralização , Fragmentos de Peptídeos/imunologia , Polissacarídeos/metabolismo , Produtos do Gene env do Vírus da Imunodeficiência Humana/imunologiaRESUMO
Lawsonella clevelandensis is a recently described anaerobic and partially acid-fast bacterium within the order Corynebacterineae. It is a fastidious microorganism that has been identified as part of the oral microbiota and is rarely associated with human infections. We describe the case of a 70-year-old man with a history of rheumatoid arthritis that developed liver abscesses and pylephlebitis. Gram stain of purulent material obtained by percutaneous drainage of the hepatic collection revealed gram-positive bacilli that stained acid-fast by the Kinyoun method. The patient was initially treated with imipenem, moxifloxacin and clarithromycin for possible Nocardia and/or nontuberculous mycobacterial infection. Cultures failed to grow the organism seen on the stains, and broad-spectrum 16S rRNA PCR gene sequencing analysis identified it as Lawsonella clevelandensis. Treatment was de-escalated to amoxicillin/clavulanic acid. The hepatic abscesses resolved completely after 4 weeks of treatment. There are only 8 documented cases of human infection caused by Lawsonella clevelandensis reported in the literature. Conventional microbiological methods do not reliably detect this bacterium, and the diagnosis relies on molecular methods. Excellent outcomes are obtained with a combined treatment approach that includes abscess drainage and prolonged antibiotic therapy.
RESUMO
Approximately 50% of the mass of the Envelope (Env) glycoprotein surface subunit (gp120) of human immunodeficiency virus type 1 (HIV-1) is composed of N-linked carbohydrate. Until now, the dogma has been that HIV-1 lacks O-linked carbohydrate on Env. Here we show that a subset of patient-derived HIV-1 isolates contain O-linked carbohydrate on the variable 1 (V1) domain of Env gp120. We demonstrate the presence of this O-glycosylation both on virions and on gp120 expressed as a secreted protein. Further, we establish that these O-linked glycans can confer a more than 1,000-fold decrease in neutralization sensitivity (IC50) to V3-glycan broadly neutralizing antibodies. These findings uncover a structural modification to the HIV-1 Env and suggest a functional role in promoting viral escape from one category of broadly neutralizing antibodies.
Assuntos
Anticorpos Amplamente Neutralizantes/metabolismo , Anticorpos Anti-HIV/imunologia , HIV-1/imunologia , HumanosRESUMO
Louis Pasteur's vaccine against rabies was introduced in France during 1885. A year later it became available within the United States. This article tells the story of the first use of the Pasteur vaccine in America and describes the early history of the vaccine's production and distribution across the country by Pasteur Institutes established for this purpose. Highlights of Pasteur's landmark studies on rabies are presented: research which pioneered the field of virology and the use of immunization to prevent infectious diseases.
Assuntos
Vacina Antirrábica/uso terapêutico , Raiva/prevenção & controle , História do Século XIX , Humanos , Vacina Antirrábica/história , Estados UnidosRESUMO
OBJECTIVE: To determine influence of age and HIV infection on influenza vaccine responses. DESIGN: Evaluate serologic response to seasonal trivalent influenza vaccine (TIV) as the immunologic outcome in HIV-infected (HIVâº) and age-matched HIV negative (HIVâ») adults. METHODS: During 2013-2016, 151 virologically controlled HIV⺠individuals on antiretroviral therapy and 164 HIVâ» volunteers grouped by age as young (<40 years), middle aged (40-59 years) and old (≥60 years) were administered TIV and investigated for serum antibody response to vaccine antigens. RESULTS: At prevaccination (T0) titers were in seroprotective range in more than 90% of participants. Antibody titers increased in all participants postvaccination but frequency of classified vaccine responders to individual or all three vaccine antigens at 3-4 weeks was higher in HIVâ» than HIV⺠adults with the greatest differences manifesting in the young age group. Of the three vaccine strains in TIV, antibody responses at T2 were weakest against H3N2 with those to H1N1 and B antigens dominating. Among the age groups, the titers for H1N1 and B were lowest in old age, with evidence of an age-associated interaction in HIV⺠persons with antibody to B antigen. CONCLUSION: Greater frequencies of vaccine nonresponders are seen in HIV⺠young compared with HIVâ» adults and the observed age-associated interaction for B antigen in HIV⺠persons are supportive of the concept of premature immune senescence in controlled HIV infection. High-potency influenza vaccination recommended for healthy aging could be considered for HIV⺠adults of all ages.
Assuntos
Envelhecimento/imunologia , Anticorpos Antivirais/sangue , Formação de Anticorpos , Infecções por HIV/imunologia , Vacinas contra Influenza/administração & dosagem , Vacinas contra Influenza/imunologia , Influenza Humana/prevenção & controle , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Hospedeiro Imunocomprometido , Peptídeos e Proteínas de Sinalização Intracelular , Masculino , Pessoa de Meia-Idade , Proteínas , Adulto JovemRESUMO
We report a case of acquired immunodeficiency syndrome (AIDS)-associated, acyclovir-refractory genital herpes infection treated with topical imidazoquinoline therapy. The patient's plasmacytoid dendritic cells made a robust interferon- alpha response following in vitro stimulation with imidazoquinoline but not with herpes simplex virus. We hypothesize that disease resulting from defective herpes simplex virus-stimulated interferon- alpha may be overcome by stimulating intact alternative pathways.
Assuntos
Aminoquinolinas/uso terapêutico , Células Dendríticas/patologia , Infecções por HIV/imunologia , Herpes Genital/tratamento farmacológico , Indutores de Interferon/uso terapêutico , Infecções Oportunistas Relacionadas com a AIDS/tratamento farmacológico , Infecções Oportunistas Relacionadas com a AIDS/virologia , Aciclovir/farmacologia , Adulto , Antivirais/farmacologia , Infecções por HIV/complicações , HIV-1/imunologia , Herpesvirus Humano 2/efeitos dos fármacos , Humanos , Imiquimode , MasculinoAssuntos
Artroplastia do Joelho , Condrocalcinose/etiologia , Complicações Pós-Operatórias , Doença Aguda , Antibacterianos/uso terapêutico , Anti-Inflamatórios não Esteroides/uso terapêutico , Pirofosfato de Cálcio/isolamento & purificação , Condrocalcinose/diagnóstico , Condrocalcinose/terapia , Desbridamento , Humanos , Indometacina/uso terapêutico , Inflamação/etiologia , Masculino , Pessoa de Meia-Idade , Pneumonia/complicações , Pneumonia/tratamento farmacológico , Líquido Sinovial/química , Vancomicina/uso terapêuticoRESUMO
Combination antiretroviral therapies (cART)can lead to normal life expectancy in HIV-infected persons, and people aged >50 yrs represent the fastest growing HIV group. Although HIV and aging are independently associated with impaired humoral immunity, immune status in people aging with HIV is relatively unexplored. In this study influenza vaccination was used to probe age associated perturbations in the B cell compartment of HIV-negative "healthy controls" (HC) and virologically controlled HIV-infected participants on cART (HIV) (n=124), grouped by age as young (<40 yrs), middle-aged (40-59yrs) or old (>60 yrs). H1N1 antibody response at d21 post-vaccination correlated inversely with age in both HC and HIV. Immunophenotyping of cryopreserved PBMC demonstrated increased frequencies of double negative B cells and decreased plasmablasts in old compared to young HC. Remarkably, young HIV were different from young HC but similar to old HC in B cell phenotype, influenza specific spontaneous (d7) or memory (d21) antibody secreting cells. We conclude that B cell immune senescence is a prominent phenomenon in young HIV in comparison to young HC, but distinctions between old HIV and old HC are less evident though both groups manifest age-associated B cell dysfunction.
Assuntos
Linfócitos B/imunologia , Senescência Celular/imunologia , Infecções por HIV/imunologia , Infecções por HIV/patologia , Adulto , Idoso , Envelhecimento/imunologia , Envelhecimento/patologia , Anticorpos Antivirais/biossíntese , Feminino , Testes de Inibição da Hemaglutinação , Humanos , Memória Imunológica , Vírus da Influenza A Subtipo H1N1/imunologia , Vacinas contra Influenza , Masculino , Pessoa de Meia-Idade , Vacinação , Adulto JovemRESUMO
We report a case of a 24-year-old immigrant from Bangladesh with Salmonella typhi meningitis, a rare disease in the United States, especially among adults. The common manifestations of meningitis such as neck rigidity and changes in mental status did not develop and Kernig sign was absent. The patient was successfully treated with intravenous ceftriaxone. This case demonstrates the importance of considering endemic infections in the country of origin when recent immigrants and returnees to the United States present with febrile illness.
Assuntos
Meningites Bacterianas/microbiologia , Meningites Bacterianas/transmissão , Infecções por Salmonella/microbiologia , Infecções por Salmonella/transmissão , Salmonella typhi/fisiologia , Viagem , Adulto , Aeronaves , Bangladesh/etnologia , Ceftriaxona/uso terapêutico , Emigração e Imigração , Humanos , Masculino , Meningites Bacterianas/tratamento farmacológico , Infecções por Salmonella/tratamento farmacológico , Estados UnidosRESUMO
Invasive pneumococcal disease (PD) occurs frequently among HIV-infected patients, but it is unclear whether its manifestations and outcome are different compared to those observed among patients without HIV-1 infection. Because the immune reconstitution that accompanies antiretroviral therapy may change some of these features and because most cases of HIV- 1 infection occur in resource-poor settings of the world where access to antiretroviral agents is limited, we compared PD among patients with and without HIV-1 infection in a North American population before the introduction of highly active antiretroviral therapy (HAART). The records of all pneumococcal cultures processed at this medical center over a period of 20 months were used to identify patients with invasive PD. Hospital records were reviewed for 103 of these patients (52 with and 51 without HIV-1 infection) and demographic, clinical, laboratory, radiographic, and microbiologic information was abstracted and subsequently analyzed. Despite similarities in presenting signs and symptoms, we found a higher incidence of bacteremia but a more favorable outcome with less frequent requirements for intubation and admission to intensive care units and better survival among individuals with HIV infection. Factors such as less advanced age, the presence of fewer comorbid conditions, or a less florid inflammatory response among HIV-infected individuals may account for differences in outcome of invasive PD.
Assuntos
Infecções por HIV/complicações , HIV-1 , Infecções Pneumocócicas/epidemiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Terapia Antirretroviral de Alta Atividade , Bacteriemia/tratamento farmacológico , Bacteriemia/epidemiologia , Bacteriemia/microbiologia , Distribuição de Qui-Quadrado , Criança , Pré-Escolar , Feminino , Florida/epidemiologia , Infecções por HIV/tratamento farmacológico , Infecções por HIV/epidemiologia , Humanos , Incidência , Lactente , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Infecções Pneumocócicas/tratamento farmacológico , Estatísticas não Paramétricas , Streptococcus pneumoniae/isolamento & purificaçãoAssuntos
Monofosfato de Adenosina/análogos & derivados , Alanina/análogos & derivados , Tratamento Farmacológico da COVID-19 , Reposicionamento de Medicamentos , Monofosfato de Adenosina/farmacologia , Monofosfato de Adenosina/uso terapêutico , Alanina/farmacologia , Alanina/uso terapêutico , Animais , Antivirais , Humanos , SARS-CoV-2/efeitos dos fármacosRESUMO
OBJECTIVE: In this study we evaluated the possibility that plasma viral load elevations secondary to influenza vaccination in HIV-1-seropositive individuals with previously undetectable viral loads (< 200 copies/ml) could develop resistance-bearing mutations in the viral reverse transcriptase (RT) and protease regions. METHODS: Thirty-four patients with undetectable viral burdens on highly active antiretroviral therapy (HAART) were evaluated for elevations in plasma viral load 2 and 4 weeks post-influenza vaccination. Plasma from patients whose viral load increased after vaccination was subject to genotypic resistance analysis by the line probe assay (LiPA) to determine whether primary resistance-bearing mutations developed during this period and at follow-up. Stored plasma was used to evaluate whether RT or protease mutations existed pre-vaccination. RESULTS: Seven out of 34 patients were found to experience elevations in their viral load after influenza vaccination. Two of the patients revealed evidence of primary RT or protease mutations not demonstrated in earlier pre-vaccination samples. One patient failed therapy after vaccination, and one patient revealed post-vaccination viral load elevations that eventually led to the progressive development of primary zidovudine mutations. CONCLUSION: Evidence is presented that supports the contention that a small subset of patients who experience viral load elevations after influenza vaccination can develop mutational changes in the RT region of the viral genome either acutely or after a failure of the viral load to return to undetectable levels.
Assuntos
Infecções por HIV/virologia , HIV-1/genética , Vacinas contra Influenza/imunologia , RNA Viral , Carga Viral , Adulto , Idoso , Fármacos Anti-HIV/uso terapêutico , Terapia Antirretroviral de Alta Atividade , Farmacorresistência Viral/genética , Feminino , Genótipo , Infecções por HIV/tratamento farmacológico , Infecções por HIV/imunologia , Inibidores da Protease de HIV/uso terapêutico , Humanos , Masculino , Pessoa de Meia-Idade , RNA Viral/sangue , Inibidores da Transcriptase Reversa/uso terapêuticoRESUMO
Despite the higher risk of anal cancer among HIV-infected individuals currently there are no national or international guidelines for anal dysplasia screening. We assessed acceptance and feasibility of screening for anal intraepithelial neoplasia (AIN), the rate of abnormalities, and relationship between the presence of AIN and a history of receptive anal intercourse. Eighty-two percent of HIV-patients approached during routine clinic visit agreed to participate in the study with anal Pap smear collection; 53% had abnormal cytology results and among those undergoing high-resolution anoscopy with biopsy, 55% had high-grade AIN, including 2 cases of carcinoma in situ. Anal cytology was well accepted and it was feasible to be incorporated into HIV primary care practice. Abnormal cytology was not significantly associated with history of anal intercourse (p = 0.767). The high rate of abnormal results reinforces the need for further evaluation of the role of systematic anal Pap smear screening for HIV patients.
Assuntos
Canal Anal/patologia , Neoplasias do Ânus/patologia , Carcinoma in Situ/patologia , Infecções por HIV/complicações , Programas de Rastreamento , Aceitação pelo Paciente de Cuidados de Saúde , Adulto , Idoso , Idoso de 80 Anos ou mais , Instituições de Assistência Ambulatorial/organização & administração , Canal Anal/virologia , Terapia Antirretroviral de Alta Atividade , Neoplasias do Ânus/diagnóstico , Neoplasias do Ânus/etiologia , Biópsia , Carcinoma in Situ/diagnóstico , Carcinoma in Situ/etiologia , Florida/epidemiologia , Infecções por HIV/tratamento farmacológico , Infecções por HIV/epidemiologia , Humanos , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Comportamento Sexual , Fatores Socioeconômicos , Estados Unidos , United States Department of Veterans Affairs , Veteranos/estatística & dados numéricosRESUMO
The increased risk of anal cancer among individuals living with HIV suggests that anal health (e.g., anal symptoms, anal practices, examination of the anus) should be an issue of priority for HIV care providers to discuss with their HIV-infected patients. We investigated the prevalence of HIV-infected individuals discussing anal health with their HIV primary care provider and factors associated with this discussion. We surveyed 518 adult patients from 5 HIV primary care clinics in Miami, Florida, from May 2004 to May 2005. Overall, only 22% of women, 32% of heterosexual men, and 54% of men who have sex with men (MSM) reported discussing anal health with their HIV providers in the prior 12 months. In a multivariable logistic regression, when adjusting for other factors, heterosexual men and MSM were 2.31 and 5.56 times, respectively, more likely to discuss anal health with their HIV providers compared to their women counterparts. Other factors associated with anal health discussion were the patients' better perception of engagement with HIV providers and having had a sexually transmitted disease exam in the past 12 months. Reporting of unprotected sex with HIV-negative or unknown HIV status was inversely related to discussion of anal health with primary care providers (odds ratio [OR] = 0.53). Efforts are greatly needed to increase the focus on anal health in the HIV primary care setting for both men and women.
Assuntos
Neoplasias do Ânus/etiologia , Neoplasias do Ânus/prevenção & controle , Infecções por HIV/complicações , Adulto , Feminino , Florida , Homossexualidade Masculina , Humanos , Modelos Logísticos , Masculino , Atenção Primária à Saúde , Relações Profissional-Paciente , Fatores de Risco , Caracteres SexuaisRESUMO
After the January 12, 2010, earthquake in Haiti, Project Medishare and the University of Miami organized, built, and staffed a 200-bed field hospital (the University of Miami Hospital in Haiti [UMHH]) on the outskirts of Port-au-Prince. We describe the operational challenges of providing a safe environment at the UMHH. Furthermore, we compared how these issues were addressed at this ad hoc hospital with how they were addressed at the field hospital of the Israel Defense Force, a fully deployable hospital with an organization fine-tuned as a result of prior disaster situations, also in Haiti.
Assuntos
Medicina de Desastres/organização & administração , Desastres , Terremotos , Controle de Infecções/organização & administração , Unidades Móveis de Saúde/organização & administração , Socorro em Desastres/organização & administração , Feminino , Haiti , Humanos , Cooperação Internacional , MasculinoRESUMO
Establishing a diagnosis of primary HIV infection (PHI) is important for both the affected individual and public health, because the newly infected individual might readily transmit HIV to others. Unfortunately, diagnosing PHI is hindered by its non-specific presentation, among other factors. We report the case of a patient with extensive multiple organ involvement (fever, rhabdomyolysis, myocarditis, pancreatitis, bilateral renal infarcts, acute renal failure and anemia) in the setting of documented HIV seroconversion as an unusual form of PHI.
Assuntos
Infecções por HIV/diagnóstico , Aborto Espontâneo , Síndrome da Imunodeficiência Adquirida/diagnóstico , Linfócitos T CD8-Positivos/imunologia , Feminino , Infecções por HIV/imunologia , HIV-1/isolamento & purificação , Humanos , Gravidez , Resultado do Tratamento , Carga Viral , Adulto JovemRESUMO
BACKGROUND: Information about the characteristics of persons whose HIV diagnosis was made soon after infection contributes to a better understanding of the HIV epidemic and to appropriate targeting of care and prevention efforts. METHODS: In 10 US cities from 1997 through 2001, specimens from consenting persons for whom a diagnosis of HIV was made within the past 12 months in were tested using the serologic testing algorithm for recent HIV seroconversion. The characteristics of those whose HIV diagnosis occurred within 170 days (on average) from seroconversion were identified. RESULTS: For 191 (20%) of the 964 participants, an HIV diagnosis was made during the period of recent infection. These diagnoses of recent infection were made more frequently among men (21.7%), whites (29.3%), men who have sex with men (25.5%), persons with a known HIV-infected partner (24.9%), and persons with a diagnosis of gonorrhea made in the 12 months before interview (27.0%). Recent infection was diagnosed less frequently among African Americans (15.5%), Latinos (15.5), and heterosexual men (14.7%) and women (14.4%). CONCLUSIONS: To increase early diagnosis of HIV, HIV testing should be more routinely offered to persons with a recent history of sexually transmitted diseases and to African Americans and Latinos in a variety of settings.
Assuntos
Sorodiagnóstico da AIDS , Infecções por HIV/imunologia , Soropositividade para HIV , Adolescente , Adulto , Cidades/epidemiologia , Feminino , Infecções por HIV/epidemiologia , Infecções por HIV/etnologia , HIV-1/imunologia , Humanos , Masculino , Pessoa de Meia-Idade , Testes Sorológicos/métodos , Comportamento Sexual , Estados Unidos/epidemiologiaRESUMO
Pulmonary nocardiosis is an uncommon but serious infection that is increasingly found in immunosuppressed persons, especially transplant recipients and persons with AIDS. The Nocardia species are denizens of soil and decaying plants that gain entry to humans through inhalation or inoculation. Pulmonary nocardiosis typically presents as an acute to subacute necrotizing pneumonia, with a variable clinical picture. Metastatic infections of the brain and subcutaneous tissues are common complications. Most clinical laboratories can isolate these microorganisms, but final speciation may be a challenge and antimicrobial susceptibility testing is especially difficult because of the slow rate of growth of Nocardia species. Full identification of species and susceptibility testing is important because of the epidemiologic implications and the difficulties of successfully treating these infections in immunosuppressed patients. Sulfonamides, including trimethoprim-sulfamethoxazole, remain the most reliable antimicrobials. Many alternative agents are active against Nocardia in vitro, but clinical data are limited.
RESUMO
Highly active antiretroviral therapy directed against HIV-1 has dramatically modified morbidity and mortality in infected individuals. Enthusiasm for the success of these medications have been tempered by an inability to clear virus from the infected host leaving a virus poised to leverage any advantage into one of productive survival. One mechanism used to accomplish escape from suppression secondary to antiretroviral therapy is by developing mutations. The goal of therapy has been to diminish viral replication, thereby effectively abrogating the development of these resistance-bearing mutations. This strategy has met with significant success but numerous host-viral factors impact on the ability of the clinician to persistently suppress viral load, thereby providing a window of opportunity for the virus to mutate. In particular we review evidence for ongoing viral replication in the face of suppressive antiretroviral therapy and viral replication in tissue compartments. We discuss whether viral resistance can develop during transient elevations in viral load (viral blips) or as a function of the rate of viral load decay while on therapy. Finally, we touch on the therapeutic strategy that diminished viral replication capacity of mutational species can maintain host immunity.
Assuntos
Fármacos Anti-HIV/uso terapêutico , Terapia Antirretroviral de Alta Atividade , Infecções por HIV/tratamento farmacológico , HIV-1/efeitos dos fármacos , Células Dendríticas Foliculares/fisiologia , Farmacorresistência Viral , Infecções por HIV/virologia , Humanos , MutaçãoRESUMO
A total of 202 methicillin-resistant Staphylococcus aureus (MRSA) single-patient isolates recovered between January and June 1998 in two hospitals in Miami, Florida, were characterized by a combination of several molecular typing techniques: multilocus sequence typing, spaA typing, pulsed-field gel electrophoresis, and determination of the structure of the SCCmec element. The overwhelming majority of the isolates-187 of 202, or 93%-belonged to one of three internationally spread epidemic clones which were identified on the basis of their multilocus sequence type (ST) as E-MRSA-16 (ST36), the New York clone V (ST8), and the New York/Japan clone (ST5; SCCmec II) and its single- and double-locus variants. The rest of the isolates (15 of 202, or 7%) were more genetically diverse and were each recovered from a few patients only. Of the 23 MRSA strains isolated from confirmed human immunodeficiency virus-positive patients, as many as 17 (or 70%) belonged to a single ST8 clone carrying SCCmec type IV. The data provide further evidence for the conclusion of earlier studies that most MRSA disease in hospitals is caused by relatively few pandemic clones.