Volume 8, Number 2—February 2002
Volume 8, Number 2—February 2002 PDF Version [PDF - 2.05 MB - 122 pages]
Vector Interactions and Molecular Adaptations of Lyme Disease and Relapsing Fever Spirochetes Associated with Transmission by Ticks
PDF Version [PDF - 106 KB - 7 pages]
T. G. Schwan and J. PiesmanView Abstract
Pathogenic spirochetes in the genus Borrelia are transmitted primarily by two families of ticks. The Lyme disease spirochete, Borrelia burgdorferi, is transmitted by the slow-feeding ixodid tick Ixodes scapularis, whereas the relapsing fever spirochete, B. hermsii, is transmitted by Ornithodoros hermsi, a fast-feeding argasid tick. Lyme disease spirochetes are generally restricted to the midgut in unfed I. scapularis. When nymphal ticks feed, the bacteria pass through the hemocoel to the salivary glands and are transmitted to a new host in the saliva after 2 days. Relapsing fever spirochetes infect the midgut in unfed O. hermsi but persist in other sites including the salivary glands. Thus, relapsing fever spirochetes are efficiently transmitted in saliva by these fast-feeding ticks within minutes of their attachment to a mammalian host. We describe how B. burgdorferi and B. hermsii change their outer surface during their alternating infections in ticks and mammals, which in turn suggests biological functions for a few surface-exposed lipoproteins.
Traditional and Molecular Techniques for the Study of Emerging Bacterial Diseases: One Laboratory’s Perspective
PDF Version [PDF - 135 KB - 9 pages]
P. Houpikian and D. RaoultView Abstract
Identification of emerging bacterial pathogens generally results from a chain of events involving microscopy, serology, molecular tools, and culture. Because of the spectacular molecular techniques developed in the last decades, some authors think that these techniques will shortly supplant culture. The key steps that led to the discovery of emerging bacteria have been reviewed to determine the real contribution of each technique. Historically, microscopy has played a major role. Serology provided indirect evidence for causality. Isolation and culture were crucial, as all emerging bacteria have been grown on artificial media or cell lines or at least propagated in animals. With the use of broad-range polymerase chain reaction, some bacteria have been identified or detected in new clinical syndromes. Culture has irreplaceable advantages for studying emerging bacterial diseases, as it allows antigenic studies, antibiotic susceptibility testing, experimental models, and genetic studies to be carried out, and remains the ultimate goal of pathogen identification.
Current Status of Antimicrobial Resistance in Taiwan
PDF Version [PDF - 96 KB - 6 pages]
P. Hsueh et al.View Abstract
While some trends in antimicrobial resistance rates are universal, others appear to be unique for specific regions. In Taiwan, the strikingly high prevalence of resistance to macrolides and streptogramin in clinical isolates of gram-positive bacteria correlates with the widespread use of these agents in the medical and farming communities, respectively. The relatively low rate of enterococci that are resistant to glycopeptide does not parallel the high use of glycopeptides and extended-spectrum beta-lactams in hospitals. The evolving problem of extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella pneumoniae isolates is substantial, and some unique enzymes have been found. Recently, some gram-negative bacteria (e.g., Pseudomonas aeruginosa and Acinetobacter baumannii) that are resistant to all available antimicrobial agents including carbapenems have emerged.
An Outbreak of Rift Valley Fever in Northeastern Kenya, 1997-98
PDF Version [PDF - 107 KB - 7 pages]
C. W. Woods et al.View Abstract
In December 1997, 170 hemorrhagic fever-associated deaths were reported in Carissa District, Kenya. Laboratory testing identified evidence of acute Rift Valley fever virus (RVFV). Of the 171 persons enrolled in a cross-sectional study, 31(18%) were anti-RVFV immunoglobulin (Ig) M positive. An age-adjusted IgM antibody prevalence of 14% was estimated for the district. We estimate approximately 27,500 infections occurred in Garissa District, making this the largest recorded outbreak of RVFV in East Africa. In multivariate analysis, contact with sheep body fluids and sheltering livestock in one’s home were significantly associated with infection. Direct contact with animals, particularly contact with sheep body fluids, was the most important modifiable risk factor for RVFV infection. Public education during epizootics may reduce human illness and deaths associated with future outbreaks.
Surveillance for Unexplained Deaths and Critical Illnesses
PDF Version [PDF - 189 KB - 9 pages]
R. A. Hajjeh et al.View Abstract
Population-based surveillance for unexplained death and critical illness possibly due to infectious causes (UNEX) was conducted in four U.S. Emerging Infections Program sites (population 7.7 million) from May 1, 1995, to December 31, 1998, to define the incidence, epidemiologic features, and etiology of this syndrome. A case was defined as death or critical illness in a hospitalized, previously healthy person, 1 to 49 years of age, with infection hallmarks but no cause identified after routine testing. A total of 137 cases were identified (incidence rate 0.5 per 100,000 per year). Patients’ median age was 20 years, 72 (53%) were female, 112 (82%) were white, and 41 (30%) died. The most common clinical presentations were neurologic (29%), respiratory (27%), and cardiac (21%). Infectious causes were identified for 34 cases (28% of the 122 cases with clinical specimens); 23 (68%) were diagnosed by reference serologic tests, and 11 (32%) by polymerase chain reaction-based methods. The UNEX network model would improve U.S. diagnostic capacities and preparedness for emerging infections.
Lack of Evidence for Human-to-Human Transmission of Avian Influenza A (H9N2) Viruses in Hong Kong, China 1999
PDF Version [PDF - 63 KB - 6 pages]
T. M. Uyeki et al.View Abstract
In April 1999, isolation of avian influenza A (H9N2) viruses from humans was confirmed for the first time. H9N2 viruses were isolated from nasopharyngeal aspirate specimens collected from two children who were hospitalized with uncomplicated, febrile, upper respiratory tract illnesses in Hong Kong during March 1999. Novel influenza viruses have the potential to initiate global pandemics if they are sufficiently transmissible among humans. We conducted four retrospective cohort studies of persons exposed to these two H9N2 patients to assess whether human-to-human transmission of avian H9N2 viruses had occurred. No serologic evidence of H9N2 infection was found in family members or health-care workers who had close contact with the H9N2-infected children, suggesting that these H9N2 viruses were not easily transmitted from person to person.
Community-Acquired Klebsiella pneumoniae Bacteremia: Global Differences in Clinical Patterns
PDF Version [PDF - 96 KB - 7 pages]
W. Ko et al.View Abstract
We initiated a worldwide collaborative study, including 455 episodes of bacteremia, to elucidate the clinical patterns of Klebsiella pneumoniae. Historically, community-acquired pneumonia has been consistently associated with K. pneumoniae. Only four cases of community-acquired bacteremic K. pneumoniae pneumonia were seen in the 2-year study period in the United States, Argentina, Europe, or Australia; none were in alcoholics. In contrast, 53 cases of bacteremic K. pneumoniae pneumonia were observed in South Africa and Taiwan, where an association with alcoholism persisted (p=0.007). Twenty-five cases of a distinctive syndrome consisting of K. pneumoniae bacteremia in conjunction with community-acquired liver abscess, meningitis, or endophthalmitis were observed. A distinctive form of K. pneumoniae infection, often causing liver abscess, was identified, almost exclusively in Taiwan.
Buruli Ulcer in Ghana: Results of a National Case Search
PDF Version [PDF - 98 KB - 4 pages]
G. Amofah et al.View Abstract
A national search for cases of Buruli ulcer in Ghana identified 5,619 patients, with 6,332 clinical lesions at various stages. The overall crude national prevalence rate of active lesions was 20.7 per 100,000, but the rate was 150.8 per 100,000 in the most disease-endemic district. The case search demonstrated widespread disease and gross underreporting compared with the routine reporting system. The epidemiologic information gathered will contribute to the design of control programs for Buruli ulcer.
Clinical Significance and Epidemiology of NO-1, an Unusual Bacterium Associated with Dog and Cat Bites
PDF Version [PDF - 39 KB - 4 pages]
R. M. Kaiser et al.View Abstract
From 1974 to 1998, 22 isolates of an unusual bacterium, designated as CDC group nonoxidizer 1 (NO-1), were sent to the Centers for Disease Control and Prevention for identification. The organism's phenotypic characteristics were similar to asaccharolytic strains of Acinetobacter, but differed in their cellular morphology and cellular fatty acid profile. We report here on NO-1's clinical and epidemiologic significance. In all cases, isolates were recovered from an animal bite wound; 17 (77%) were isolated from a dog bite wound, 4 (18%) from a cat bite wound, and one (5%) from an unspecified animal bite. Clinical data were retrieved and reviewed for 12 (55%) of the 22 bite victims. None of the patients had pre-existing conditions associated with immunosuppression. Seven (58%) patients were hospitalized for a median stay of 5 days (range, 2 to 11 days). The median time between bite to the worsening of symptoms was 17.5 hours (range, 3 to 78 hours). All patients recovered following antibiotic treatment.
Comparative Antibiotic Resistance of Diarrheal Pathogens from Vietnam and Thailand, 1996-1999
PDF Version [PDF - 77 KB - 6 pages]
D. W. Isenbarger et al.View Abstract
Antimicrobial resistance rates for shigella, campylobacter, nontyphoidal salmonella, and enterotoxigenic Escherichia coli were compared for Vietnam and Thailand from 1996 to 1999. Resistance to trimethoprim-sulfamethoxazole, ampicillin, chloramphenicol, and tetracycline was common. Quinolone resistance remains low in both countries, except among campylobacter and salmonella organisms in Thailand. Nalidixic acid resistance among salmonellae has more than doubled since 1995 (to 21%) in Thailand but is not yet documented in Vietnam. Resistance to quinolones correlated with resistance to azithromycin in both campylobacter and salmonella in Thailand. This report describes the first identification of this correlation and its epidemiologic importance among clinical isolates. These data illustrate the growing magnitude of antibiotic resistance and important differences between countries in Southeast Asia.
Epidemiology of Burkholderia cepacia Complex in Patients with Cystic Fibrosis, Canada
PDF Version [PDF - 75 KB - 7 pages]
D. P. Speert et al.View Abstract
The Burkholderia cepacia complex is an important group of pathogens in patients with cystic fibrosis (CF). Although evidence for patient-to-patient spread is clear, microbial factors facilitating transmission are poorly understood. To identify microbial clones with enhanced transmissibility, we evaluated B. cepacia complex isolates from patients with CF from throughout Canada. A total of 905 isolates from the B. cepacia complex were recovered from 447 patients in 8 of the 10 provinces; 369 (83%) of these patients had genomovar III and 43 (9.6%) had B. multivorans (genomovar II). Infection prevalence differed substantially by region (22% of patients in Ontario vs. 5% in Quebec). Results of typing by random amplified polymorphic DNA analysis or pulsed-field gel electrophoresis indicated that strains of B. cepacia complex from genomovar III are the most potentially transmissible and that the B. cepacia epidemic strain marker is a robust marker for transmissibility.
Broad-Range Bacterial Detection and the Analysis of Unexplained Death and Critical Illness
PDF Version [PDF - 76 KB - 7 pages]
S. Nikkari et al.View Abstract
Broad-range rDNA polymerase chain reaction (PCR) provides an alternative, cultivation-independent approach for identifying pathogens. In 1995, the Centers for Disease Control and Prevention initiated population-based surveillance for unexplained life-threatening infections (Unexplained Death and Critical Illness Project [UNEX]). To address the causes of UNEX cases, we examined 59 specimens from 46 cases by using broad-range bacterial 16S rDNA PCR and phylogenetic analysis of amplified sequences. Specimens from eight cases yielded sequences from Neisseria meningitidis (cerebrospinal fluid from two patients with meningitis), Streptococcus pneumoniae (cerebrospinal fluid from one patient with meningitis and pleural fluid from two patients with pneumonia), or Stenotrophomonas maltophilia (bone marrow aspirate from one patient with pneumonia). Streptococcus pneumoniae rDNA sequence microheterogeneity was found in one pleural fluid specimen, suggesting the presence of multiple strains. In conclusion, known bacterial pathogens cause some critical illnesses and deaths that fail to be explained with traditional diagnostic methods.
Antibiotic Resistance Patterns of Bacterial Isolates from Blood in San Francisco County, California, 1996-1999
PDF Version [PDF - 86 KB - 7 pages]
S. S. Huang et al.View Abstract
Countywide antibiotic resistance patterns may provide additional information from that obtained from national sampling or individual hospitals. We reviewed susceptibility patterns of selected bacterial strains isolated from blood in San Francisco County from January 1996 to March 1999. We found substantial hospital-to-hospital variability in proportional resistance to antibiotics in multiple organisms. This variability was not correlated with hospital indices such as number of intensive care unit or total beds, annual admissions, or average length of stay. We also found a significant increase in methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus, and proportional resistance to multiple antipseudomonal antibiotics. We describe the utility, difficulties, and limitations of countywide surveillance.
Prosthetic Valve Endocarditis Caused by Bartonella quintana
PDF Version [PDF - 27 KB - 2 pages]
J. L. Klein et al.View Abstract
We describe the first case of Bartonella quintana endocarditis affecting a prosthetic valve in a person with no known risk factors for this infection. Bartonella should be considered as a cause of endocarditis in any clinical setting.
Cryptosporidium muris Infection in an HIV-Infected Adult, Kenya
PDF Version [PDF - 53 KB - 3 pages]
W. Gatei et al.View Abstract
We describe a case of Cryptosporidium muris infection in an HIV-infected adult with diarrhea in Kenya. Sequence analysis of an 840-bp region of the 18S rRNA gene locus demonstrated the isolate had 100% nucleotide identity with C. muris recovered from a rock hyrax, 98.8% with a C. muris “calf” isolate, 95.5% with C. serpentis, but only 87.8% with C. parvum “human” type.
Rickettsia felis Infection Acquired in Europe and Documented by Polymerase Chain Reaction
PDF Version [PDF - 34 KB - 2 pages]
J. Richter et al.
Hemorrhagic Fever with Renal Syndrome Presenting with Hemophagocytic Lymphohistiocytosis
PDF Version [PDF - 36 KB - 2 pages]
J. Lee et al.View Abstract
Hemophagocytic lymphohistiocytosis--which is associated with a variety of infections, malignant neoplasms, autoimmune diseases, and immunodeficiencies--is an uncommon syndrome with a rapidly fatal outcome. We describe the first case of hemorrhagic fever with renal syndrome due to Hantaan virus presenting with reactive hemophagocytosis.
Distemper Outbreak and Its Effect on African Wild Dog Conservation
PDF Version [PDF - 61 KB - 2 pages]
M. W. van de Bildt et al.View Abstract
In December 2000, an infectious disease spread through a captive breeding group of African wild dogs (Lycaon pictus) in Tanzania, killing 49 of 52 animals within 2 months. The causative agent was identified as Canine distemper virus (CDV) by means of histologic examination, virus isolation, reverse transcriptase-polymerase chain reaction analysis, and nucleotide sequencing. This report emphasizes the importance of adequate protection against infectious diseases for the successful outcome of captive breeding programs of endangered species.
Postexposure Treatment and Animal Rabies, Ontario, 1958-2000
PDF Version [PDF - 40 KB - 4 pages]
C. P. Nunan et al.View Abstract
This paper investigates the relationship between animal rabies and postexposure treatment (PET) in Ontario by examining the introduction of human diploid cell vaccine (HDCV) in 1980 and the initiation of an oral rabies vaccination program for wildlife in 1989. Introducing HDCV led to an immediate doubling of treatments. Both animal rabies and human treatments declined rapidly after the vaccination program was introduced, but human treatments have leveled off at approximately 1,000 per year.
PDF Version [PDF - 23 KB - 1 page]
Medicine to Kill, Medicine to Heal
PDF Version [PDF - 23 KB - 1 page]
N. Shulman and Z. Haugo
Multidrug-Resistant Pseudomonas Aeruginosa Bloodstream Infections: Analysis of Trends in Prevalence and Epidemiology
PDF Version [PDF - 37 KB - 2 pages]
E. Tacconelli et al.
About the Cover
Experimentation du virus charbonneux: “Le Pelerin,” 1922. Homage a Louis Pasteur. Dessin de Damblans.
PDF Version [PDF - 27 KB - 1 page]
Clinical Issues in the Prophylaxis, Diagnosis, and Treatment of Anthrax
PDF Version [PDF - 40 KB - 4 pages]
D. M. Bell et al.
Public Health Assessment of Potential Biological Terrorism Agents
PDF Version [PDF - 54 KB - 6 pages]
L. D. Rotz et al.
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