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P R Georghiou

Publications and source records attributed to P R Georghiou.

18 recordsLinked to original sources
PubMed1996

Characterization of two unusual clinically significant Francisella strains.

We have isolated two phenotypically distinct nonfastidious Francisella strains (Fx1 and Fx2) from the blood of compromised patients with pneumonia and compared them with eight other Francisella strains, including Francisella tularensis biovar tularensis, F. tularensis biovar novicida, and F. philomiragia. Our isolates grew well on sheep blood agar, chocolate agar, modified Thayer-Martin agar, and Trypticase soy agar. Fx1 and Fx2 were determined to be within the Francisella genus by cellular fatty acid analysis and by the utilization of glucose, production of H2S and catalase, and lack of motility, oxidase, nitrate reductase, and gelatinase. They were additionally shown to belong to the species F. tularensis by sequencing of two variable regions comprising approximately 500 nucleotides of the 16S rRNA gene. Also, RNA probe hybridization confirmed their belonging to the species F. tularensis. However, the new strains, which are not identical, are distinguished from other F. tularensis strains by growth characteristics, repetitive extragenic palindromic PCR fragment pattern, and some biochemical tests. Key biochemical differences included the findings that Fx1 was positive for beta-galactosidase and arabinose hydrolysis and that both strains were citrulline ureidase positive and glycerol negative. Commercial F. tularensis antiserum agglutinated stock F. tularensis strains but not Fx1, Fx2, F. tularensis biovar novicida, or F. philomiragia; serum from either patient failed to agglutinate or only weakly agglutinated commercial antigen but showed agglutination when tested against each patient's respective isolate. Fx1 and Fx2 produced beta-lactamase. Because of their good growth, negative serology, and biochemical profile, the organisms could be misidentified in the clinical laboratory if standard strategies or commercial identification systems are used.

Adult↗
PubMed1995

An outbreak of Burkholderia (formerly Pseudomonas) cepacia respiratory tract colonization and infection associated with nebulized albuterol therapy.

OBJECTIVE: To investigate an outbreak of Burkholderia (formerly Pseudomonas) cepacia respiratory tract colonization and infection in mechanically ventilated patients. DESIGN: A retrospective case-control and bacteriologic study. SETTING: Veterans Affairs medical center. PATIENTS: 42 mechanically ventilated patients who developed respiratory tract colonization or infection with B. cepacia and 135 ventilator-dependent controls who were not colonized and did not develop infections. MEASUREMENTS: Clinical and demographic data; benzalkonium chloride concentrations and pH levels in albuterol sulfate solutions; repetitive-element polymerase chain reaction (PCR)-mediated molecular fingerprinting on eight patient isolates and three environmental B. cepacia isolates that were available for study. RESULTS: 42 patients had B. cepacia respiratory tract colonization or infection. Observation of intensive care unit and respiratory care personnel showed faulty infection control procedures (for example, the same multiple-dose bottle of albuterol was used for many mechanically ventilated patients). More case patients (39 [92.9%]) than controls (95 [70.4%]; P = 0.006) received nebulized albuterol, and case patients (67.5 treatments) received more treatments than controls (18 treatments; P < 0.001). In-use albuterol solutions had pH values that were unstable, and benzalkonium chloride concentrations declined over time to levels capable of supporting bacterial growth. Medication nebulizers and in-use bottles of albuterol harbored B. cepacia. Molecular fingerprints of patient isolates and environmental B. cepacia isolates were identical using repetitive-element PCR. No further isolates of B. cepacia were identified after institution of appropriate infection control procedures. CONCLUSIONS: Multiple-dose medications and reliance on benzalkonium chloride as a medication preservative provide a mechanism for nosocomial spread of microorganisms, particularly if infection control procedures are not carefully followed. Repetitive-element PCR is a useful fingerprinting technique for molecular epidemiologic studies of B. cepacia.

Aged↗
PubMed1995

Molecular epidemiology of infections due to Enterobacter aerogenes: identification of hospital outbreak-associated strains by molecular techniques.

Molecular techniques were used to study the epidemiology of infections due to Enterobacter aerogenes in a tertiary-care hospital. Sixty-two clinical isolates were collected from 43 patients over 3 months. Restriction endonuclease analysis (REA) of chromosomal DNA and repetitive-element polymerase chain reaction (rep-PCR) with primers based on repetitive extragenic palindromic (REP) and enterobacterial repetitive intergenic consensus (ERIC) bacterial DNA sequences were used for genomic fingerprinting. REA with HindIII or EcoRI yielded complex banding patterns that differentiated community-acquired from some hospital-acquired organisms. Less complex fingerprints were obtained with rep-PCR, which also distinguished between epidemiologically unrelated strains. More discriminatory DNA fingerprints were provided by rep-PCR when REP primers rather than ERIC primers were used. Two clusters of genomically distinct isolates from patients with recent or current exposure to the hospital environment were identified by REA and rep-PCR. Most isolates within each cluster contained characteristic plasmids, and some isolates contained additional plasmids. These results suggest colonization and infection with genotypically related strains of E. aerogenes in a nosocomial setting. Although REA and plasmid profiling are useful techniques for the epidemiological typing of E. aerogenes, genomic fingerprinting with rep-PCR may offer the advantages of ease, speed, and broad species applicability over existing molecular-typing techniques.

Adult↗
PubMed1995

Thalidomide as treatment of refractory aphthous ulceration related to human immunodeficiency virus infection.

In recent years, thalidomide has been used for the treatment of a variety of ulcerative and immunologic conditions. Several previous reports have suggested that thalidomide therapy is beneficial for patients with aphthous ulceration related to human immunodeficiency virus (HIV) infection. We describe the use of thalidomide in 20 HIV-infected patients with oropharyngeal, esophageal, and rectal ulceration. Nineteen patients had a dramatic response to thalidomide therapy, with both subjective and objective abatement in the signs and symptoms of their ulcerative disease. The standard treatment course was 200 mg of thalidomide for 14 days (the drug was administered at night). Four patients required additional courses of treatment because symptoms recurred after thalidomide therapy was stopped. Side effects due to thalidomide included rash (5 patients), peripheral neuropathy (1 patient), and excessive fatigue (1 patient). There did not appear to be any adverse immunologic effects in thalidomide-treated patients. The mechanism of the effect of thalidomide is uncertain, although recent studies have suggested that thalidomide selectively inhibits the production of tumor necrosis factor alpha.

Adult↗
PubMed1995

Case report: vitamin D-mediated hypercalcemia in fungal infections.

Hypercalcemia has been well described in a variety of neoplastic and granulomatous diseases. One mechanism for this hypercalcemia is via the excess production of 1,25-dihydroxyvitamin D from extra-renal sources. The authors describe an AIDS patient infected with Cryptococcus neoformans who had suggestive evidence of vitamin D-mediated hypercalcemia. He had an elevated serum 1,25-dihydroxyvitamin D value, a normal 25-hydroxyvitamin D value, and low values for parathyroid hormone and parathyroid hormone-related peptide. Most previously reported cases of hypercalcemia associated with fungal infections did not include sufficient evidence to implicate a role for excess 1,25-dihydroxyvitamin D production, except for two case reports involving patients with hypercalcemia with infections due to Pneumocystis carinii and Candida albicans. The authors' patient's hypercalcemia resolved during treatment of his underlying infection. Patients with hypercalcemia or in whom hypercalcemia develops during a disseminated fungal infection should have vitamin D metabolites measured as part of their work-up.

AIDS-Related Opportunistic Infections↗
PubMed1995

Fistula-in-ano: an unusual presentation of chronic schistosomiasis.

A 30 year old Ethiopian man presented with recurrent perianal abscess and fistula-in-ano. Ova of Schistosoma mansoni were found on fecal microscopy, and were subsequently identified in fibrous tissue excised from the fistula tract. Chronic schistosomiasis should be recognized as a rare cause of fistula-in-ano. Treatment of schistosomiasis with praziquantel may prevent further complications of this condition.

Adult↗
PubMed1995

Genomic fingerprinting of Bartonella species by repetitive element PCR for distinguishing species and isolates.

Repetitive-element PCR (rep-PCR) with primers based on repetitive extragenic palindromic (REP) and enterobacterial repetitive intergenic consensus (ERIC) repeated DNA sequences was used for genomic finger-printing of Bartonella species. This technique was applied by using either extracted genomic DNA or preparations of whole bacterial cells directly. PCR fingerprints with either the REP-based primers (REP-PCR) or primers based on the ERIC repeat (ERIC-PCR) revealed species-specific band patterns for the various Bartonella isolates. DNA fingerprints obtained from rep-PCR of extracted genomic DNA or from preparations of whole cells yielded comparable patterns. ERIC-PCR banding patterns were less complex than those obtained by REP-PCR but allowed better discrimination between strains within species. By combining results of REP-PCR and ERIC-PCR, five different fingerprint profiles were identified among 17 isolates of Bartonella henselae, but only one profile was identified among the five isolates of Bartonella quintana. Other Bartonella species yielded distinct rep-PCR fingerprints. rep-PCR is a useful technique for identification of Bartonella organisms to the species level and offers the advantage of ease of performance, with only small quantities of cells needed for the whole-cell procedure. This technique also appears to be useful for subtyping B. henselae isolates.

AIDS-Related Opportunistic Infections↗
PubMed1994

Molecular fingerprinting of Legionella species by repetitive element PCR.

Repetitive element PCR (rep-PCR) uses outward-facing primers to amplify multiple segments of DNA located between conserved repeated sequences interspersed along the bacterial chromosome. Polymorphisms of rep-PCR amplification products can serve as strain-specific molecular fingerprints. Primers directed at the repetitive extragenic palindromic element were used to characterize isolates of Legionella pneumophila and other Legionella species. Substantial variation was seen among the rep-PCR fingerprints of different Legionella species and serogroups. More limited, but distinct, polymorphisms of the rep-PCR fingerprint were evident among epidemiologically unrelated isolates of L. pneumophila serogroup 1. Previously characterized Legionella isolates from nosocomial outbreaks were correctly clustered by this method. These results suggest the presence of repetitive extragenic palindromic-like elements within the genomes of members of the family Legionellaceae that can be used to discriminate between strains within a serogroup of L. pneumophila and between different Legionella species. rep-PCR appears to be a useful technique for the molecular fingerprinting of Legionella species.

DNA Fingerprinting↗
PubMed1993

Classification of respiratory tract picornavirus isolates as enteroviruses or rhinoviruses by using reverse transcription-polymerase chain reaction.

The classification of picornaviruses isolated from respiratory secretions as human rhinoviruses (HRVs) or enteroviruses (EVs) by using reverse transcription-polymerase chain reaction was compared to that derived from acid lability testing. Of the 135 clinical isolates examined, 91 were found to be HRVs and 44 were EVs. There was 100% concordance between the two classification methods. Reverse transcription-polymerase chain reaction is an effective alternative to traditional methods for differentiating HRVs from EVs.

Base Sequence↗
PubMed1993

DNA-based identification and epidemiologic typing of bacterial pathogens.

Genotypic, or DNA-based, methods have become increasingly applicable for infectious disease diagnosis and epidemiologic analysis. The ability to assess the pathogen's genotype directly bypasses requirements for cultivation and may diminish diagnostic delays with fastidious organisms. Genotypic typing methods have enhanced epidemiologic studies by providing techniques with greater discriminatory ability and smaller proportions of nontypeable samples. Hence, these methods enable rigorous studies to be performed regarding the nature of disease outbreaks. Phenotypic, or conventional, methods will remain important in diagnostic microbiology, especially with organisms that are relatively easy to culture. However, genotypic methods may become increasingly prominent in clinical microbiology laboratories, particularly with respect to diagnosis of fastidious pathogens, because of their relative speed, versatility, and lack of cultivation requirements.

Bacteria↗
PubMed1992

Infection with Nocardia species in Queensland. A review of 102 clinical isolates.

OBJECTIVE: To review the species distribution, pathologic significance and disease associations of clinical isolates of Nocardia and related bacteria in Queensland, and to examine the characteristics, treatment and outcome of patients infected with these organisms. DESIGN AND SETTING: A retrospective review of Queensland State Health Laboratory records provided microbiological data for Nocardia isolates referred from other laboratories during the period January 1983 to December 1988. Clinical information was extracted from hospital case notes, or obtained from detailed questionnaires completed by attending physicians. Nocardia isolates were classified as "significant" if specific treatment for nocardiosis was given, or on the basis of autopsy findings. PATIENTS: One hundred and two patients had a Nocardia species or a related organism isolated from clinical specimens during the study period. RESULTS: The 102 isolates included Nocardia asteroides (45), N, brasiliensis (35), N. caviae (5) and N. transvalensis (5). Clinical results were available for 93 patients, of whom 74 (80%) had a significant isolate recovered. Primary pulmonary or disseminated disease occurred in 35 patients, and was caused mainly by N. asteroides. Significant infections of skin and soft tissues, primarily due to N. brasiliensis, were found in 39 patients. Preexisting lung disease and treatment with steroids and immunosuppression were risk factors for pulmonary and disseminated nocardiosis. A history of inoculation in an outdoor setting was frequent in patients with cutaneous disease. Antibiotic regimens that included trimethoprim-sulfamethoxazole or another sulfonamide agent were used to treat the majority of patients with significant infection. Deaths were confined to those with pulmonary and disseminated disease, with a case fatality rate of 40% in that group. CONCLUSION: Infection with Nocardia species appears to be more common than is generally appreciated. The local species distribution and disease spectrum are similar to those described elsewhere. A high index of suspicion for nocardiosis should be maintained in susceptible hosts with pulmonary infiltrates, particularly when there is evidence for metastatic infection, and in patients with superficial infections and a history of outdoor injury.

Adolescent↗
PubMed1992

Infections due to Nocardia transvalensis: clinical spectrum and antimicrobial therapy.

Nocardia transvalensis, a rare Nocardia species, has previously been recognized as a cause of actinomycotic mycetoma. In a retrospective review of N. transvalensis isolates referred to the Centers for Disease Control (Atlanta) during the period January 1981 through January 1990, we identified 15 patient isolates. Four N. transvalensis isolates originated from one Australian reference laboratory; one patient's isolate that was identified by the Australian laboratory but that was not received at the Centers for Disease Control was also included in our study. A review of the cases of these 16 patients found that N. transvalensis caused infection in 10 patients and colonization in two patients. Six (75%) of eight patients with primary pulmonary or disseminated N. transvalensis infections had an underlying immunologic disorder or were receiving immunosuppressive therapy; three patients with disseminated infection died. All nine infected patients for whom specific antimicrobial therapy was prescribed received trimethoprim-sulfamethoxazole. Results of in vitro antimicrobial susceptibility tests of 11 N. transvalensis isolates revealed increased antimicrobial resistance to amikacin and other drugs when compared with that of other Nocardia species. Severely immunocompromised patients are predisposed to N. transvalensis pneumonia or disseminated infection, and the lung may be the portal of entry.

Adolescent↗
PubMed1991

Branhamella (Moraxella) catarrhalis: pathogenic significance in respiratory infections.

OBJECTIVES: To assess the pathogenic significance of Branhamella catarrhalis isolates in patients with respiratory infections and to define the clinical characteristics of such patients. DESIGN AND SETTING: Respiratory specimens were assessed in a three-year prospective study performed in a Brisbane metropolitan hospital. Assessment of the pathogenic significance of isolates of B. catarrhalis was based on four predetermined criteria: (i) clinical evidence of respiratory infection based on history, examination and chest x-ray; (ii) isolation of B. catarrhalis as the sole potential pathogen; (iii) absence of antibiotic treatment in the previous two weeks; and (iv) subsequent clinical response to an antibiotic to which the isolate was sensitive. RESULTS: B. catarrhalis was identified in 118 respiratory samples, 92 (78%) being from patients less than 10 years old. Infection with B. catarrhalis was more commonly seen in winter months and was community-acquired in two-thirds of cases. Isolation of this organism was associated with a broad variety of upper and lower respiratory tract syndromes. Isolates were considered to be of pathogenic significance (all four above criteria satisfied) in 35% of cases and of possible significance (the first and fourth criteria satisfied) in a further 15% of cases. Isolates were more likely to be of pathogenic significance in older patients and in those with pre-existing cardiorespiratory disease; however, a number of serious infections were observed in previously-well children. Expectorated sputum and tracheal aspirates were more likely to yield a clinically significant isolate than nasopharyngeal aspirates. Production of beta-lactamase was demonstrated in 88% of isolates. CONCLUSION: B. catarrhalis causes respiratory infection more frequently than is generally appreciated. Isolation of this organism from the respiratory tract had pathogenic significance or possible pathogenic significance in 50% of our patients. If therapy is indicated in patients with respiratory infection caused by this organism, traditional beta-lactam regimens cannot be relied upon, as shown by the high rate of beta-lactamase production in this study; a tetracycline, erythromycin, a second or third generation cephalosporin, or the combination of a penicillin derivative and beta-lactamase inhibitor should be considered.

Adolescent↗
PubMed1989

Near-fatal septicaemia with Chromobacterium violaceum.

Chromobacterium violaceum is a Gram-negative organism which normally inhabits water and soil. Human infection is unusual and is associated with a high mortality rate. We describe a typical case of disseminated infection with Chr. violaceum in a male carpet cleaner. The possible origin and treatment of the infection is discussed.

Adult↗