Legionnaires' disease on a cruise ship linked to the water supply system: clinical and public health implications. (1/1055)

The occurrence of legionnaires' disease has been described previously in passengers of cruise ships, but determination of the source has been rare. A 67-year-old, male cigarette smoker with heart disease contracted legionnaires' disease during a cruise in September 1995 and died 9 days after disembarking. Legionella pneumophila serogroup 1 was isolated from the patient's sputum and the ship's water supply. Samples from the air-conditioning system were negative. L. pneumophila serogroup 1 isolates from the water supply matched the patient's isolate, by both monoclonal antibody subtyping and genomic fingerprinting. None of 116 crew members had significant antibody titers to L. pneumophila serogroup 1. One clinically suspected case of legionnaires' disease and one confirmed case were subsequently diagnosed among passengers cruising on the same ship in November 1995 and October 1996, respectively. This is the first documented evidence of the involvement of a water supply system in the transmission of legionella infection on ships. These cases were identified because of the presence of a unique international system of surveillance and collaboration between public health authorities.  (+info)

Natural competence for DNA transformation by Legionella pneumophila and its association with expression of type IV pili. (2/1055)

We have recently described the expression of two pili of different lengths on the surface of Legionella pneumophila (B. J. Stone and Y. Abu Kwaik, Infect. Immun. 66:1768-1775, 1998). Production of long pili requires a functional pilEL locus, encoding a type IV pilin protein. Since type IV pili in Neisseria gonorrhoeae are associated with competence for DNA transformation, we examined the competence of L. pneumophila for DNA transformation under conditions that allowed the expression of type IV pili. We show that L. pneumophila is naturally competent for DNA transformation by isogenic chromosomal DNA and by plasmid DNA containing L. pneumophila DNA. Many different L. pneumophila loci are able to transform L. pneumophila after addition of plasmid DNA, including gspA, ppa, asd, and pilEL. The transformation frequency is reduced when competing DNA containing either L. pneumophila DNA or vector sequences is added to the bacteria, suggesting that uptake-specific sequences may not be involved in DNA uptake. Competence for DNA transformation correlates with expression of the type IV pili, and a pilEL mutant defective in expression of type IV pili is not competent for DNA transformation. Complementation of the mutant for competence is restored by the reintroduction of a cosmid that restores production of type IV pili. Minimal competence is restored to the mutant by introduction of pilEL alone. We conclude that competence for DNA transformation in L. pneumophila is associated with expression of the type IV pilus and results in recombination of L. pneumophila DNA into the chromosome. Since expression of type IV pili also facilitates attachment of L. pneumophila to mammalian cells and protozoa, we designated the type IV pili CAP (for competence- and adherence-associated pili).  (+info)

Concurrent infection with Legionella pneumophila and Pneumocystis carinii in a patient with adult T cell leukemia. (3/1055)

A 48-year-old woman was admitted to our hospital with high fever, chills, cough, and exertional dyspnea. On admission, the chest roentgenogram and computed tomography scan showed bilateral alveolar infiltration in the middle and lower lung fields. Microscopic examination of the bronchial lavage fluid showed flower cells typical for adult T-cell leukemia (ATL) and cysts of Pneumocystis carinii, and Legionella pneumophila serogroup 1 grew on buffered charcoal yeast extract (BCYE)-alpha agar. The patient was successfully treated with antibiotics including trimethoprim/sulfamethoxazole, erythromycin, and sparfloxacin. Remission of ATL was achieved after three courses of antileukemic chemotherapy. Mixed infection of opportunistic pathogens should be considered in patients with ATL.  (+info)

Legionella pneumophila utilizes the same genes to multiply within Acanthamoeba castellanii and human macrophages. (4/1055)

In previous reports we described a 22-kb Legionella pneumophila chromosomal locus containing 18 genes. Thirteen of these genes (icmT, -R, -Q, -P, -O, -M, -L, -K, -E, -C, -D, -J, and -B) were found to be completely required for intracellular growth and killing of human macrophages. Three genes (icmS, -G, and -F) were found to be partially required, and two genes (lphA and tphA) were found to be dispensable for intracellular growth and killing of human macrophages. Here, we analyzed the requirement of these genes for intracellular growth in the protozoan host Acanthamoeba castellanii, a well-established important environmental host of L. pneumophila. We found that all the genes that are completely required for intracellular growth in human macrophages are also completely required for intracellular growth in A. castellanii. However, the genes that are partially required for intracellular growth in human macrophages are completely required for intracellular growth in A. castellanii. In addition, the lphA gene, which was shown to be dispensable for intracellular growth in human macrophages, is partially required for intracellular growth in A. castellanii. Our results indicate that L. pneumophila utilizes the same genes to grow intracellularly in both human macrophages and amoebae.  (+info)

Surface-associated heat shock proteins of Legionella pneumophila and Helicobacter pylori: roles in pathogenesis and immunity. (5/1055)

Bacterial heat shock proteins (Hsps) are abundantly produced during the course of most microbial infections and are often targeted by the mammalian immune response. While Hsps have been well characterized for their roles in protein folding and secretion activities, little attention has been given to their participation in pathogenesis. In the case of Legionella pneumophila, an aquatic intracellular parasite of protozoa and cause of Legionnaires' disease, Hsp60 is uniquely located in the periplasm and on the bacterial surface. Surface-associated Hsp60 promotes attachment and invasion in a HeLa cell model and may alter an early step associated with the fusion of phagosomes with lysosomes. Avirulent strains of L. pneumophila containing defined mutations in several dot/icm genes are defective in localizing Hsp60 onto their surface and are reduced approximately 1000-fold in their invasiveness towards HeLa cells. For the ulcer-causing bacterium Helicobacter pylori, surface-associated Hsp60 and Hsp70 mediate attachment to gastric epithelial cells. The increased expression of these Hsps following acid shock correlates with both increased association with and inflammation of the gastric mucosa. A role for Hsps in colonization, mucosal infection and in promoting inflammation is discussed.  (+info)

Molecular typing of Legionella pneumophila serogroup 1 by pulsed-field gel electrophoresis with SfiI and comparison of this method with restriction fragment-length polymorphism analysis. (6/1055)

A panel of 131 well-characterised Legionella pneumophila serogroup 1 strains, previously used to evaluate a restriction fragment-length polymorphisms (RFLP) typing scheme, was examined by pulsed-field gel electrophoresis (PFGE) with the restriction endonuclease SfiI. The data obtained show that PFGE with SfiI is a highly discriminatory method yielding an index of discrimination (IOD) of 0.992 and 0.975, with 100% and 90% similarity thresholds respectively, compared with an IOD of 0.909 for the RFLP typing method. Reproducibility of PFGE profiles within gels was excellent and it was possible to compare the profiles visually. However, the reproducibility of the technique between gels was poor and visual comparison of the patterns was extremely difficult. Computer-aided analysis assisted the assessment of inter-gel reproducibility. Of 11 duplicates examined only four pairs showed 100% similarity, although 9 of 11 showed > or =90% similarity. In an attempt to determine if the PFGE banding patterns were sufficiently unambiguous to allow the method to be used as a definitive typing method, 20 coded strains were examined. At a 90% similarity level, 16 of these were placed in the correct PFGE type and four were not allocated to a type. Partial digestion of DNA by SfiI was noted despite careful control of DNA and enzyme concentrations, suggesting that an alternative enzyme might give more reproducible results.  (+info)

Multiple types of Legionella pneumophila serogroup 6 in a hospital heated-water system associated with sporadic infections. (7/1055)

Five sporadic cases of nosocomial Legionnaires' disease were documented from 1989 to 1997 in a hospital in northern Italy. Two of them, which occurred in a 75-year-old man suffering from ischemic cardiopathy and in an 8-year-old girl suffering from acute leukemia, had fatal outcomes. Legionella pneumophila serogroup 6 was isolated from both patients and from hot-water samples taken at different sites in the hospital. These facts led us to consider the possibility that a single clone of L. pneumophila serogroup 6 had persisted in the hospital environment for 8 years and had caused sporadic infections. Comparison of clinical and environmental strains by monoclonal subtyping, macrorestriction analysis (MRA), and arbitrarily primed PCR (AP-PCR) showed that the strains were clustered into three different epidemiological types, of which only two types caused infection. An excellent correspondence between the MRA and AP-PCR results was observed, with both techniques having high discriminatory powers. However, it was not possible to differentiate the isolates by means of ribotyping and analysis of rrn operon polymorphism. Environmental strains that antigenically and chromosomally matched the infecting organism were present at the time of infection in hot-water samples taken from the ward where the patients had stayed. Interpretation of the temporal sequence of events on the basis of the typing results for clinical and environmental isolates enabled the identification of the ward where the patients became infected and the modes of transmission of Legionella infection. The long-term persistence in the hot-water system of different clones of L. pneumophila serogroup 6 indicates that repeated heat-based control measures were ineffective in eradicating the organism.  (+info)

Pneumothorax complicating fatal bronchiolitis obliterans organizing pneumonia. (8/1055)

Bronchiolitis obliterans organizing pneumonia (BOOP) is an uncommon pulmonary disorder, the clinical spectrum of which is variable. We present a fatal case of BOOP, which developed spontaneous pneumothorax, a complication considered rare. Unusual was also the upper lobe distribution of the infiltrates. The histologically diagnosed disease failed to respond to antibiotics and corticosteroids and the 74-year-old patient eventually succumbed with acute respiratory distress syndrome, 50 days after disease onset. Spontaneous pneumothorax should be added to the complications of BOOP, which may adversely affect prognosis.  (+info)