Rima F. Khabbaz

The emergence of methicillin-resistant Staphylococcus aureus infections in United States hospitals. Possible role of the house staff-patient transfer circuit.

Infections with methicillin-resistant strains of Staphylococcus aureus appear to be occurring with increasing frequency in some U.S. hospitals about a decade after a similar increase in Britain and other countries. In the United States, clustered methicillin-resistant S. aureus infections reported in scientific journals and in three hospital surveys have been almost entirely in large, tertiary referral hospitals affiliated with medical schools. Among 63 hospitals regularly reporting infections from 1974 to 1981 in the National Nosocomial Infections Study, the increase in methicillin-resistant S. aureus infections was entirely due to substantial increases in only four hospitals, all of which were large, tertiary referral centers affiliated with medical schools. The predominance of methicillin-resistant S. aureus infections in these large hospitals may be due to the large numbers of patients at high risk of infection and to the interhospital spread of the organism by the transfer of infected patients and house staff from similar hospitals or from nursing homes.Abstract Infections with methicillin-resistant strains ofStaphylococcus aureusappear to be occurring with increasing frequency in some U.S. hospitals about a decade after a similar increase in Brit...

Seroprevalence of HTLV-I and HTLV-II among Intravenous Drug Users and Persons in Clinics for Sexually Transmitted Diseases

Abstract Background. The human T-cell lymphotropic virus Type I (HTLV-I) is associated with adult T-cell leukemia and myelopathy, whereas HTLV-II infection has uncertain clinical consequences. We assessed the seroprevalence of these retroviruses among intravenous drug users and among patients seen at clinics for sexually transmitted diseases (STD clinics). Methods. We used serum samples that were collected in eight cities in 1988 and 1989 during surveys of human immunodeficiency virus infection among intravenous drug users entering treatment and persons seen in STD clinics. The serum samples were tested for antibodies to HTLV, and positive specimens were tested further by a synthetic peptide-based enzyme-linked immunosorbent assay to differentiate between HTLV-I and HTLV-II. Results. Among 3217 intravenous drug users in 29 drug-treatment centers, the median seroprevalence rates of HTLV varied widely according to city (range, 0.4 percent in Atlanta to 17.6 percent in Los Angeles). Seroprevalence increased ...

Male-to-female transmission of human T-cell lymphotropic virus types I and II : Association with viral load

SUMMARY Risk factors for male-to-female sexual transmission of human T-lymphotropic virus types I and II (HTLV-I/II) were investigated among HTLV-seropositive volunteer blood donors and their long-term (> or = 6 month) sex partners. Direction of transmission in concordantly seropositive pairs was assessed by analyzing risk factors for HTLV infection. Donors and their partners were also questioned regarding sexual behaviors during their relationships; HTLV antibody titers and viral load were determined for specimens from male partners. Among 31 couples in whom HTLV-infected men likely transmitted infection to their partners (11 HTLV-I and 20 HTLV-II) and 25 male-positive, female-negative couples (8 HTLV-I and 17 HTLV-II), HTLV transmitter men had been in their relationships longer (mean 225 months vs. 122 months) and had higher viral loads (geometric mean 257,549 vs. 2,945 copies/300,000 cells for HTLV-I; 5,541 vs. 118 copies/300,000 cells for HTLV-II) than non-transmitters (P = 0.018 and P = 0.001 for duration of relationship and viral load, respectively, logistic regression analysis). Transmitter men also tended to have higher antibody titers against various env and whole virus proteins than non-transmitters. The identification of high viral load and duration of relationship as risk factors provides a biologically plausible framework in which to assess risk of sexual transmission of the HTLVs.

Prospective microbiologic surveillance in control of nosocomial methicillin-resistant Staphylococcus aureus.

A prospective microbiological surveillance (PMS) program was developed in a comprehensive hospital-wide effort for control of nosocomial methicillin-resistant Staphylococcus aureus (MRSA). This PMS program entailed: active identification of colonized and infected patients; application of a screening microbiologic system for MRSA; isolation of colonized and infected patients; antibiotic decolonization of MRSA; and educational efforts. The PMS program was studied over three and one half years for its contribution to infection control of MRSA, early identification of nosocomial MRSA outbreaks, use of the highest yield surveillance culture sites, and cost effectiveness. Following initiation of the PMS program in December 1982, during an MRSA outbreak, the frequency of new MRSA cases declined from 14 to none by the end of a 3-month pilot study. The frequency of new MRSA cases stabilized at approximately 2 per month until October 1983, when the PMS system allowed prompt detection of a new outbreak of 11 cases. Following isolation and antibiotic decolonization, the frequency of cases again declined to 3 per month. A third outbreak in December 1985 again was promptly detected and controlled. Infection to colonization ratio decreased from a maximum of 1.5 during outbreaks to a minimum of 0.17 after outbreaks. Wounds and tracheostomy sites provided the greatest yield of detection of new cases of MRSA. During one 15-month period, 35 of the 43 new cases were detected initially at wounds and tracheostomy sites. No new MRSA cases were detected by a positive axillary or nares site alone. The estimated quarterly cost of outbreaks and infection paralleled the quarterly frequency of new MRSA cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Hantavirus pulmonary syndrome in Florida: Association with the newly identified Black Creek Canal virus

Hantavirus pulmonary syndrome (HPS) is a recently recognized viral zoonosis. The first recognized cases were caused by a newly described hantavirus. Sin Nombre virus (previously known as Muerto Canyon virus), isolated from Peromyscus maniculatus (deer mouse). We describe a 33-year-old Floridian man who resided outside the ecologic range of P maniculatus but was found to have serologic evidence of a hantavirus infection during evaluation of azotemia associated with adult respiratory distress syndrome. Small mammal trapping conducted around this patients residence demonstrated the presence of antihantaviral antibodies in 13% of Sigmodon hispidus [cotton rat). Serologic testing using antigen derived from the Black Creek Canal hantavirus subsequently isolated from this rodent established that this patient was acutely infected with this new pathogenic American hantavirus. HPS is not confined to the geographical distribution of P maniculatus and should be suspected in individuals with febrile respiratory syndromes, perhaps associated with azotemia, throughout the continental United States.

Inhalational Anthrax Outbreak among Postal Workers, Washington, D.C., 2001

In October 2001, four cases of inhalational anthrax occurred in workers in a Washington, D.C., mail facility that processed envelopes containing Bacillus anthracis spores. We reviewed the envelopes’ paths and obtained exposure histories and nasal swab cultures from postal workers. Environmental sampling was performed. A sample of employees was assessed for antibody concentrations to B. anthracis protective antigen. Case-patients worked on nonoverlapping shifts throughout the facility. Environmental sampling showed diffuse contamination of the facility, suggesting multiple aerosolization events. Potential workplace exposures were similar for the case-patients and the sample of workers. All nasal swab cultures and serum antibody tests were negative. Available tools could not identify subgroups of employees at higher risk for exposure or disease. Prophylaxis was necessary for all employees. To protect postal workers against bioterrorism, measures to reduce the risk of occupational exposure are necessary.

Simian immunodeficiency virus needlestick accident in a laboratory worker

The macaque monkey infected with simian immunodeficiency virus (SIV) is an animal model of the acquired immunodeficiency syndrome. We investigated a laboratory worker who was exposed by needlestick accident to blood from an SIV-infected macaque. Seroreactivity to SIV developed within 3 months of exposure, with antibody titres peaking from the third to the fifth month and declining thereafter. Polymerase chain reaction for SIV sequences and cultures of peripheral-blood mononuclear cells failed to show infection. Inoculation of an SIV-negative monkey with blood from the worker did not cause infection. Animal-care and laboratory workers should adhere strictly to recommended procedures to avoid accidental exposures when working with SIV-infected animals or specimens.

Challenges of infectious diseases in the USA.

Summary In the USA, infectious diseases continue to exact a substantial toll on health and health-care resources. Endemic diseases such as chronic hepatitis, HIV, and other sexually transmitted infections affect millions of individuals and widen health disparities. Additional concerns include health-care-associated and foodborne infections—both of which have been targets of broad prevention efforts, with success in some areas, yet major challenges remain. Although substantial progress in reduction of the burden of vaccine-preventable diseases has been made, continued cases and outbreaks of these diseases persist, driven by various contributing factors. Worldwide, emerging and reemerging infections continue to challenge prevention and control strategies while the growing problem of antimicrobial resistance needs urgent action. An important priority for control of infectious disease is to ensure that scientific and technological advances in molecular diagnostics and bioinformatics are well integrated into public health. Broad and diverse partnerships across governments, health care, academia, and industry, and with the public, are essential to effectively reduce the burden of infectious diseases.

Oversight and monitoring of blood safety in the United States

The US blood safety vigilance system is composed of a network of interwoven programs, now organized under a formal structure, with the Assistant Secretary of Health and DHHS Blood Safety Committee bearing overall responsibility. It takes advantage of the breadth of expertise and close collaborative relationship of transfusion medicine and infectious disease scientists within and outside of the government. Core elements include an array of ongoing surveillance programs for monitoring established as well as new and emerging infectious agents that may pose a risk to blood safety, and the existence of historical and contemporary repositories of donor and recipient specimens that enable rapid investigation of putative new risks. This report summarizes the historical events that shaped the US blood safety oversight system, reviews the current organization and decision–making processes related to blood safety issues, and highlights key surveillance systems and research programs which monitor the US and global blood supplies for known and potential emerging risks.

Hantavirus and Arenavirus Antibodies in Persons with Occupational Rodent Exposure, North America

Risk for infection was low among those who handled neotomine or sigmodontine rodents on the job.