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R Dagan

Publications and source records attributed to R Dagan.

At least 37 records · Page 2Linked to original sources
PubMed2001

Evidence to support the rationale that bacterial eradication in respiratory tract infection is an important aim of antimicrobial therapy.

Clinical outcome is dependent upon antibiotic-mediated bacterial eradication in a number of infections. However, in respiratory tract infections, the need for bacterial eradication has been controversial. Clinical data are now available that support the need for active bacterial eradication in otitis media. This may also be the case for other respiratory tract infections. An increase in antimicrobial resistance reduces the probability of achieving eradication. Conversely, failure to eradicate bacteria may promote the emergence and dissemination of antimicrobial-resistant clones. Pharmacokinetic/pharmacodynamic parameters can be used to predict the bacteriological efficacy of antimicrobial therapy. In conclusion, the aim of antimicrobial therapy in respiratory tract infections should be the eradication of the infecting organism.

Anti-Bacterial Agents↗
PubMed2001

Bacteriologic and clinical efficacy of trimethoprim-sulfamethoxazole for treatment of acute otitis media.

BACKGROUND: Trimethoprim-sulfamethoxazole (T/S) has often been used as first and second line of treatment for acute otitis media (AOM). Because of the increasing resistance of Streptococcus pneumoniae and Haemophilus influenzae to T/S, we undertook the present study to investigate the bacteriologic and clinical efficacy of this drug in AOM. METHODS: Fifty-four culture-positive evaluable patients ages 3 to 32 months with AOM were treated with T/S 4/20 mg/kg in two divided daily doses for 10 days. Middle ear fluid (MEF) was cultured at enrollment (Day 1) and on Days 4 and 5 after initiation of treatment. Additional MEF cultures were obtained if clinical relapse occurred. Clinical failure was determined when the symptoms and signs of AOM did not improve or recurred during therapy. Bacteriologic failure was defined by positive culture on Days 4 and 5, or negative on Days 4 and 5 but positive again before the end of treatment. Patients were followed until Day 28 +/- 2. RESULTS: A total of 67 organisms were isolated from MEF specimens of the 54 study patients: S. pneumoniae, 24; H. influenzae, 40; and Streptococcus pyogenes, 3. Fifteen (63%) of 24 S. pneumoniae were nonsusceptible to T/S (trimethoprim MIC, >0.5 microg/ml), of which 10 (67%) were highly resistant to T/S (trimethoprim MIC, > or = 4.0 microg/ml). Twelve (30%) of 40 H. influenzae and all 3 S. pyogenes isolates were nonsusceptible to T/S (MIC > or = 4.0 microg/ml). Bacteriologic eradication occurred in 9 of 9 (100%) and 27 of 27 (100%) T/S-susceptible S. pneumoniae and H. influenzae, respectively, vs. 4 of 15 (27%) and 6 of 12 (50%) T/S-nonsusceptible S. pneumoniae and H. influenzae, respectively (P < 0.001). The 3 patients with S. pyogenes failed bacteriologically. Nine new organisms, not initially isolated, emerged during treatment, 7 of which (77%) were resistant to T/S. Altogether bacteriologic failure (organisms not eradicated plus newly emerged) occurred in 29 (53%) of 54 patients. Clinical failures occurred in 8 (15%) of 54 patients, and in 7 of these 8 cases the clinical failures occurred in those with bacteriologic failures. Ten patients relapsed clinically after completion of treatment and in 8 of them tympanocentesis for MEF culture was performed. Six of these 8 cultures were positive, and the initial pathogen was isolated in 4 of 6 (67%). CONCLUSIONS: A high bacteriologic failure rate as well as a considerable clinical failure rate occurred among patients with AOM treated with T/S. We believe that T/S is no longer an appropriate empiric choice for the treatment of AOM in regions where high T/S resistance among respiratory pathogens is reported.

Acute Disease↗
PubMed2001

Tolerability and immunogenicity of an eleven-valent pneumococcal conjugate vaccine in healthy toddlers.

BACKGROUND: A need to increase the serotype coverage of pneumococcal conjugate vaccines exists. The use of a single carrier protein may cause overload of the carrier and decrease the immune response by not providing sufficient carrier-specific T helper cell support. A vaccine composed of a mixture of tetanus- and diphtheria-conjugated polysaccharides (PS) is a potential solution to this issue. OBJECTIVES: The aim of this study was to assess the tolerability and immunogenicity in healthy toddlers of an 11-valent pneumococcal conjugate vaccine that uses both tetanus and diphtheria toxoids as carriers. We explored the effect of an aluminum adjuvant on safety and immunogenicity by comparing the vaccine with and without adjuvant. METHODS: Twenty Finnish and 23 Israeli toddlers received the conjugate vaccine with or without aluminum adjuvant. Safety data were recorded for 5 days after vaccination. Sera were obtained before and 28 days after the immunization. IgG antibodies to the 11 vaccine-type PSs were determined by enzyme immunoassay. RESULTS: No serious adverse events occurred. The formulation with the adjuvant tended to induce fewer local but more systemic reactions than the non-adjuvant-containing formulation. Both vaccine formulations induced significant IgG increases for the vaccine-specific PSs. Types 3 and 7F were the most immunogenic; antibodies reached a concentration of 1 microg/ml in all individuals. Conjugates of types 6B, 14 and 23F were the weakest immunogens; antibodies reached the concentration of 1 microg/ml in 36, 27 and 32% of the individuals in the nonadjuvant group and in 53, 38 and 53% in the adjuvant group, respectively. CONCLUSIONS: An 11-valent mixed carrier pneumococcal conjugate vaccine is safe and immunogenic in toddlers. The use of an adjuvant do not seem to offer any significant benefit.

Adjuvants, Immunologic↗
PubMed2001

Early responses to nonconjugated polyribosylribitol phosphate challenge as evidence of immune memory after combined diphtheria-tetanus-pertussis-polio-Haemophilus influenzae type b primary vaccination.

OBJECTIVES: A high risk of invasive Haemophilus influenzae type b (Hib) disease exists in the first few years of life. A reduction in anti-polyribosylribitol phosphate (PRP) antibody concentrations follows the administration of certain diphtheria-tetanus-acellular pertussis (DTPa)-based Hib conjugate combined vaccines. However, these combined vaccines prime the immune memory, which is an important factor in protection. As yet there is no direct evidence of the time scale involved in the development of the immune memory post-primary vaccination. In this report we investigated the presence of immune memory at 10 and 12 months of age, 4 and 6 months after primary vaccination of young infants with a pentavalent combination of DTPa, inactivated poliovirus vaccine (IPV) and Hib (DTPa-IPV/Hib) vaccine. METHODS: In two trials (A and B) infants received DTPa-IPV combined with Hib-tetanus conjugate (PRP-T) vaccine at 2, 4 and 6 months of age. The presence of immune memory was assessed by measuring anti-PRP concentrations 7 to 10 days after a nonconjugated PRP challenge given at 10 months in Trial A and at 12 months in Trial B. RESULTS: Administration of a nonconjugated PRP challenge 4 and 6 months after primary vaccination in Trials A and B, respectively, elicited an increase in anti-PRP geometric mean concentrations (4.5 and 5.8 microg/ml, respectively) within 7 to 10 days. These concentrations exceed those reported in the literature involving unprimed children who had received a single dose of nonconjugated PRP at the same age. CONCLUSION: The results demonstrate the development of anti-PRP immune memory at an early age, 4 and 6 months after completion of a three dose primary vaccination course of combined DTPa-IPV/Hib vaccine. The ability of primed infants to mount a rapid response is an important observation given the high risk of Hib infection at this critical age.

Antibodies, Bacterial↗
PubMed2001

Bacteriologic and clinical efficacy of high dose amoxicillin/clavulanate in children with acute otitis media.

OBJECTIVES: To determine the bacteriologic and clinical efficacy of high dose amoxicillin/clavulanate (90/6.4 mg/kg/day) against common bacterial pathogens causing acute otitis media (AOM), including penicillin-resistant Streptococcus pneumoniae (PRSP). METHODS: In this open label multicenter study, 521 infants and children with AOM [mean age, 18.6 months; age < 24 months, n = 375 (72%)] were treated with amoxicillin/clavulanate 90/6.4 mg/kg/day in two divided doses for 10 days. Bilateral otitis media, previous episodes of AOM, antibiotic treatment within 3 months and day-care attendance were recorded in 60.1, 35.7, 50.2 and 38.2% of the children, respectively. Tympanocentesis was performed before the first dose and repeated on Days 4 to 6 for all children with S. pneumoniae at 22 centers and for all children with any pathogen at 3 centers. Clinical response was assessed at end of therapy. RESULTS: Pathogens were isolated from 355 (68%) of 521 enrolled children; 180 children underwent repeat tympanocentesis and were bacteriologically evaluable. Baseline pathogens were S. pneumoniae (n = 122 enrolled/93 bacteriologically evaluable), Haemophilus influenzae (n = 160/51), both (n = 37/32) and others (n = 36/4). Pathogens were eradicated from 172 (96%) of 180 bacteriologically evaluable children. Overall 122 (98%) of 125 isolates of S. pneumoniae were eradicated, including 31 (91%) of 34 PRSP isolates (penicillin MICs 2 to 4 micrograms/ml). Seventy-eight (94%) of 83 isolates of H. influenzae were eradicated. Symptoms and otoscopic signs of acute inflammation were completely resolved or improved on Days 12 to 15 in 263 (89%) of 295 clinically evaluable children with bacteriologically documented AOM. CONCLUSIONS: On the basis of bacteriologic outcome on Days 4 to 6 and clinical outcome on Days 12 to 15, we found that high dose amoxicillin/clavulanate (90/6.4 mg/kg/day) was highly efficacious in children with AOM, including those most likely to fail treatment, namely children < 24 months of age and those with infectious caused by PRSP.

Acute Disease↗
PubMed2001

Effect of a conjugate pneumococcal vaccine on the occurrence of respiratory infections and antibiotic use in day-care center attendees.

BACKGROUND: Incidence and severity of respiratory infections are increased in day-care center attendees. Streptococcus pneumoniae is an important contributor to these infections. OBJECTIVE: To examine whether the use of a pneumococcal conjugate vaccine could reduce the occurrence of respiratory infections and the ensuing antibiotic drug use in the day care. METHOD: In this double blind, randomized, controlled study performed in 8 day-care centers located in Beer-Sheva, Israel, 264 toddlers ages 12 to 35 months at enrollment were randomized to receive either a 9-valent conjugate pneumococcal vaccine (conjugated to CRM197) or a control vaccine [conjugate meningococcus C vaccine (conjugated to CRM197)] and were followed for an average of 22 months. The main outcome measures were respiratory morbidity and antibiotic use. RESULTS: An overall reduction of 7% in child months with > or = 1 reported illness episodes was observed among vaccinees (P = 0.008), and 85% of all episodes were related to the respiratory tract. Reductions of 15, 16 and 17% were observed in upper respiratory infections, lower respiratory problems and otitis media, respectively. An overall reduction of 17% in antibiotic days was observed [10% for upper respiratory infections, 20% for otitis and 47% for lower respiratory problems (P < or = 0.005 for each entity)]. The reduction in episodes and antibiotic use was greater for those <36 months of age than for the older children. CONCLUSION: The reduction of respiratory problems, including those not traditionally considered of pneumococcal origin and the ensuing lowered antibiotic use in day-care center attendees by pneumococcal conjugate vaccination suggest a broader benefit from the vaccine than preventing invasive disease only.

Acidosis, Respiratory↗
PubMed2001

Early onset pneumococcal sepsis in children hospitalized for noninfectious life-threatening events.

During a 13-year period 9 patients admitted to a pediatric intensive care unit for life-threatening noninfectious conditions developed pneumococcal sepsis within 48 h of admission. All patients were Bedouins, a population group characterized by high prevalence of respiratory carriage of Streptococcus pneumoniae. In populations with high carriage rates of S. pneumoniae, critically ill children appear to be at increased risk of pneumococcal sepsis.

Arabs↗
PubMed2001

Identification and characterization of a novel family of pneumococcal proteins that are protective against sepsis.

Four pneumococcal genes (phtA, phtB, phtD, and phtE) encoding a novel family of homologous proteins (32 to 87% identity) were identified from the Streptococcus pneumoniae genomic sequence. These open reading frames were selected as potential vaccine candidates based upon their possession of hydrophobic leader sequences which presumably target these proteins to the bacterial cell surface. Analysis of the deduced amino acid sequences of these gene products revealed the presence of a histidine triad motif (HxxHxH), termed Pht (pneumococcal histidine triad) that is conserved and repeated several times in each of the four proteins. The four pht genes (phtA, phtB, phtD, and a truncated version of phtE) were expressed in Escherichia coli. A flow cytometry-based assay confirmed that PhtA, PhtB, PhtD and, to a lesser extent, PhtE were detectable on the surface of intact bacteria. Recombinant PhtA, PhtB, and PhtD elicited protection against certain pneumococcal capsular types in a mouse model of systemic disease. These novel pneumococcal antigens may serve as effective vaccines against the most prevalent pneumococcal serotypes.

Amino Acid Sequence↗
PubMed2001

Evaluation of a medium (STGG) for transport and optimal recovery of Streptococcus pneumoniae from nasopharyngeal secretions collected during field studies.

Field studies of Streptococcus pneumoniae (pneumococci) nasopharyngeal (NP) colonization are hampered by the need to directly plate specimens in order to ensure isolate viability. A medium containing skim milk, tryptone, glucose, and glycerin (STGG) has been used to transport and store NP material, but its ability to preserve pneumococci has not been evaluated. Our objective was to qualitatively and semiquantitatively evaluate the ability of STGG to preserve pneumococci in NP secretions. Entwined duplicate calcium alginate NP swab samples were obtained from children. One swab was plated directly onto a gentamicin blood agar plate; the other was placed in STGG. Growth from the directly plated specimen was compared with growth from an STGG aliquot immediately cultured or stored at -70 degrees C for 9 weeks, -20 degrees C for 9 weeks, or 4 degrees C for 5 days. Of 186 specimens, 96 (52%) were positive for pneumococci from the direct plating; 94 (98%) of these were positive from the fresh STGG specimen. Pneumococci were recovered from all 38 positive specimens frozen at -70 degrees C, all 18 positive specimens frozen at -20 degrees C, and 18 of 20 positive specimens stored at 4 degrees C. Recovery of pneumococci after storage of NP material in STGG medium at -70 degrees C is at least as good as that from direct plating. Storage at -20 degrees C is also acceptable. Storage at 4 degrees C for 5 days is not ideal.

Child, Preschool↗
PubMed2001

Persistence of two invasive Streptococcus pneumoniae clones of serotypes 1 and 5 in comparison to that of multiple clones of serotypes 6B and 23F among children in southern Israel.

We conducted a study to examine the clonal distribution of invasive serotype 1 and 5 isolates as representatives of serotypes that are rarely carried by healthy individuals compared to that of invasive serotype 6B and 23F isolates as representatives of serotypes often carried by young children for prolonged periods. All invasive serotype 1, 5, 6B, and 23F isolates recovered from blood cultures during January 1995 to May 1999 were analyzed; these included 66 serotype 1, 30 serotype 5, 11 serotype 6B, and 15 serotype 23F isolates. One hundred thirty-three nasopharyngeal (NP) isolates of the indicated four serotypes from healthy children were also studied. The strains were characterized using serotyping, antimicrobial susceptibility testing, and pulsed-field gel electrophoresis profiling. We found that both invasive and NP serotype 1 and 5 isolates were susceptible to penicillin and that each serotype showed only one clonal type. In contrast, serotype 6B and 23F strains showed different phenotypic characteristics as well as multiple clonal types; 10 clones were identified among 6B isolates, and 11 clones were identified among 23F isolates.

Anti-Bacterial Agents↗
PubMed2001

[Characteristics of nasopharyngeal carriage of Streptococcus pneumoniae in children during acute respiratory disease].

Streptococcus pneumoniae is an important cause of pediatric morbidity and its main reservoir is the nasopharynx, from which it can disseminate and cause invasive disease. From November 1997 through March 1998, nasopharyngeal carriage of S. pneumoniae was evaluated in 250 children under the age of 36 months: 123 Jews and 127 Bedouins with acute respiratory disease and in 980 healthy control children (852 Jews and 128 Bedouins). Carriage rate was higher among sick children. Among Jewish children it was 57% and 35% of sick and healthy children respectively (p < 0.01), and among Bedouin children it figured as 80% and 67% respectively (p = 0.01). The difference in carriage rate was most prominent in infants under the age of 5 months: among Jewish children it was 60% and 27% of sick and healthy children respectively (p < 0.001) and among Bedouins it was 82% and 65% respectively (p = 0.05). Higher carriage rate of penicillin resistant pneumococci (PRP) was also detected in sick children, with no relation to antibiotic treatment in the month prior to sampling. In Jewish children PRP was detected in 12%, 28% (p < 0.001) and 36% (p < 0.001) of healthy children, sick children with previous antibiotic treatment and sick children with no treatment, respectively. The seroypes included in the newly developed 7-valent conjugate vaccine: 4, 6B, 9V, 14, 18C, 19F, 23F, that are highly pathogenic and often antibiotic resistant contributed 74% of isolates in sick Jewish children who had previous antibiotic treatment and 39% of isolates in healthy children (p < 0.001). In Bedouin children vaccine types carriers rate among the sick children was not higher than in healthy children. Acute respiratory disease increases the risk of pneumococcal carriage in general and carriage of resistant pneumococci in particular. Previous antibiotic treatment increases the risk of carring one of the pathogenic serotypes included in the 7-valent vaccine. The impact of disease is most prominent in infants under 5 months, since they are usually less exposed to S. pneumoniae carriers than older children. Since the increase in carriage rate during illness is mostly due to the serotypes included in the newly developed conjugate vaccine, future immunization programme may decrease not only morbidity rate but also nasopharyngeal carriage rate of pneumococci in general and of antibiotic-resistant pneumococci in particular.

Acute Disease↗
PubMed2001

[The sensitivity of common bacteria to antibiotics in children in southern Israel].

BACKGROUND: Many reports describe an increasing antibiotic resistance among various pathogenic bacteria. Since every empiric antibiotic treatment is also based on the expected antibiogram of the probable isolate, it is essential to frequently monitor the resistance trends at different ages and contexts. AIM: The purpose of this study was to monitor the antibiogram of a large bacterial population isolated from pediatric bacteremia episodes. METHODS: All bacteremia episodes of children under the age of 18 years in the Soroka Medical Center, Beer Sheva, Israel, were prospectively documented from January 1990 to December 1998. RESULTS: Of the 5,373 positive blood cultures that were noted during the study period, 1,689 were considered as true different episodes. During the years 1990-92, 1993-95 and 1996-98 454, 538 and 697 episodes were noted, respectively. The most common pathogens were Streptococcus pneumoniae (447 isolates), Staphylococcus aureus (224 isolates), Escherichia coli (187 isolates) and Klebsiella spp (180 isolates). The antibiotic sensitivity of the pathogens declined with time in some of the cases and increased in others. The major problems raised were the development of ESBL (extended spectrum beta lactamase) and MRSA (methacillin resistant Staphylococcus aureus) producing isolates, high level of resistance of coagulase negative Staphylococci and Acinetobacter to most of the antibiotic agents, and increasing resistance of Streptococcus pneumoniae to various agents. CONCLUSION: Despite the significant increase in the antibiotic resistance of many of the pathogens tested, there are still various therapeutic options available.

Bacteremia↗
PubMed2000

Treatment of acute otitis media - challenges in the era of antibiotic resistance.

The last decade is characterized by the increase in antibiotic resistance among respiratory bacterial pathogens in the presence of only modest progress in the development of new antibacterial agents to overcome this resistance. A series of recent studies show clearly that the increased resistance among the main AOM pathogens (namely Streptococcus pneumoniae and Haemophilus influenzae) is associated with a dramatic decrease in bacteriologic response to antibiotic treatment, which in turn has an impact on clinical response. Thus, the individual patient is affected by the increasing antibiotic resistance. Moreover, the society as a whole is now also affected because the carriage and spread of antibiotic resistant AOM pathogens is remarkably impacted by antibiotic treatment. New studies show the remarkable ability of antibiotics to rapidly promote nasopharyngeal carriage and spread of antibiotic-resistant AOM pathogens. In these studies, the increase in carriage of antibiotic resistant S. pneumoniae is shown already after 3-4 days from initiation of antibiotic treatment and may last for weeks to months after treatment. Children carrying antibiotic-resistant organisms transmit those organisms to their family and to their day care centers and thus a vicious cycle is created in which increased antibiotic resistance with decreased response leads to increased antibiotic use, which in turn leads to further increase in resistance. New antibiotics are not likely to improve this situation. It is clear that the challenge in the next decade is to prevent AOM rather than to treat it. Efforts to prevent AOM include improved environmental factors, immunization with bacterial and viral vaccines and some creative measures such as prevention of colonization and attachment to epithelium of AOM pathogens. Whether these efforts will prove successful or, even if successful, will only modify the clinical and bacteriologic picture presenting new challenges, only time will tell.

Anti-Bacterial Agents↗
PubMed2000

A comparison of multiple regimens of pneumococcal polysaccharide-meningococcal outer membrane protein complex conjugate vaccine and pneumococcal polysaccharide vaccine in toddlers.

Children who had been randomized to receive one dose of either heptavalent pneumococcal polysaccharide-meningococcal outer membrane protein complex conjugate vaccine (PCV) or 23-valent pneumococcal polysaccharide vaccine (PN23) at 12, 15, or 18 months of age were subsequently randomized to receive a booster injection of either PCV or PN23 12 months later. For those children who received a priming dose of PCV (N=75) compared to PN23 (N=48) at 12, 15, or 18 months of age, higher serum antibody concentrations were achieved 1 month following a booster injection of either PCV or PN23 for all serotypes tested (p<0.001). Within the group of children receiving a priming dose of PCV, those children who received a booster dose of PN23 developed higher serum antibody concentrations for four of the seven serotypes tested and similar opsonic antibody titers to serotype 6B, yet more frequent erythema (p=0.030) and pain or soreness (p=0.024) at the injection site compared to those boosted with PCV. In conclusion, a single dose of PCV at 12-18 months of age primed for responses to booster doses of either PCV or PN23 12 months later. For those children who received a priming dose of PCV, boosting with PN23 resulted in more frequent injection site pain and erythema than boosting with PCV, yet higher antibody concentrations for most of the serotypes tested.

Antibodies, Bacterial↗
PubMed2000

[Development of molecular tests for rapid detection of enteropathogens].

Amplification of specific DNA sequences by polymerase chain reaction (PCR), enables rapid, sensitive and direct, specific identification of pathogens at very low concentrations in clinical samples. Studies in recent years have reported identification of several enteropathogens directly from stool samples by PCR. The amplification process includes the use of primers complementary to the DNA sequences specific to the pathogen, thus relying on the pathogen's genotype, rather than its phenotype on which identification by the methods of classical microbiology were based. We have developed PCR protocols for the differential identification of enteropathogens resembling the normal flora (enterotoxigenic E. coli (ETEC), E. coli O-157), Shigella spp, and the detection of enteropathogens that can not be grown on classic growth media (Norwalk virus). The amplification process is inhibited by several substrates present in fecal material (phenol, hemoglobin), limiting DNA extraction by phenol. The protocols we have developed for direct detection of Shigella spp and ETEC in stools circumvent inhibition of PCR by the use of a 4-hour pre-enrichment step in brain-heart infusion broth. Rapid and accurate identification of enteropathogens is important for prompt and focused intervention to stop the chain of transmission in outbreaks of gastroenteritis in military and civilian populations.

Dysentery, Bacillary↗
PubMed2000

Acute otitis media caused by antibiotic-resistant Streptococcus pneumoniae in southern Israel: implication for immunizing with conjugate vaccines.

The potential coverage of antibiotic-resistant pneumococci causing acute otitis media (AOM) by 7-, 9-, and 11-valent conjugate pneumococcal vaccines was studied in southern Israel. A total of 876 cases of pneumococcal AOM were studied in the context of various clinical conditions. Of the isolates, 68% were resistant to >/=1 drug, 61% were resistant to penicillin, and 13% were resistant to >/=3 antibiotic classes. Antibiotic resistance and coverage by the various candidates were age and population dependent and were higher among those with a complicated clinical course, as indicated by recent antibiotic use and recurrence of AOM. The results suggest that, if efficacious, the conjugate pneumococcal vaccines can substantially reduce the occurrence of pneumococcal AOM in general and complicated pneumococcal AOM in particular.

Acute Disease↗
PubMed2000

Initial steps in Streptococcus pneumoniae interaction with and pathogenicity to the host.

Streptococcus pneumoniae (Pnc) is one of the leading pathogens in the world. Attachment to respiratory mucosal and lung surfaces is presumed to be involved in carriage, in disease and in the interaction with macrophages initiating innate immune responses. We hypothesized that bacterial adhesins mediate Pnc adhesion and host cell invasiveness. Initial studies have focused on the purification of cell wall and membrane proteins using fetuin affinity chromatography, SDS PAGE and western blot analysis probed with pooled healthy human sera. Using a Pnc clinical isolate, and a gpt mutant we have detected 10-lectin proteins isolated from the cell wall and adherent to the affinity column and 15 lectins isolated from membrane extracts. The fetuin-captured lectins agglutinated rabbit erythrocytes. 15 proteins in the cell wall and 18 proteins in the membrane that failed to bind to the fetuin column did not agglutinate rabbit erythrocytes. Further purification of the cell wall and membrane fetuin-separated fractions was achieved via anion exchange FPLC, was verified by SDS PAGE. These proteins maintained their agglutinating activity, and were subsequently tested for their ability to interfere with Pnc adhesion and invasion of epithelial cells in culture. Additional biochemical, immunological and molecular techniques are being used in attempt to identify relevant proteins.

Adult↗