PubMed Health⌕ Search

Biomedical subjects

R R Facklam

Publications and source records attributed to R R Facklam.

At least 73 records · Page 4Linked to original sources
PubMed1995

Correlation between phenotypic characteristics and DNA relatedness within Enterococcus faecium strains.

We noted that a number of enterococcal strains isolated from human clinical specimens resembled Enterococcus faecium but were able to produce acid from glycerol, raffinose, and/or sorbitol, while others failed to form acid from mannitol. An additional concern was that many of these strains with atypical phenotypic characteristics also appeared to acquire vancomycin resistance. In order to determine if such atypical strains were variants of E. faecium or new Enterococcus species, 35 E. faecium or E. faecium-like strains (grouped into 10 phenotypes on the basis of the results of the following tests: capacity to form acid from glycerol, mannitol, raffinose, or sorbitol and susceptibility to vancomycin) and four strains of Enterococcus faecalis were taken from our culture collection, analyzed for their whole-cell protein profiles by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and identified to the species level by DNA-DNA reassociation experiments. All E. faecium-like strains, including four mannitol-negative variants, conformed to at least two of three DNA-DNA relatedness criteria: they were 70% or more related to the type strain of E. faecium at optimal conditions, they had less than 5% divergence within the related sequences, and they had a relatedness of 60% or greater under stringent conditions. The protein profiles of atypical strains were similar to those of typical strains and were easily distinguishable from those of E. faecalis and other enterococcal species. The five E. faecalis strains were 12 to 16% related to the E. faecium type strain. These results indicate that the phenotypic description of E. faecium should include all of these variable characteristics.

Bacterial Proteins↗
PubMed1995

Comparison of M and T type antigen testing to field inversion gel electrophoresis in the differentiation of strains of group A streptococcus.

Recent clusters of patients with acute rheumatic fever and invasive group A Streptococcus (GAS) have stimulated renewed interest in the epidemiology of streptococcal infections. We compared conventional serotyping for M and T antigens and serum opacity factor with field inversion gel electrophoresis (FIGE) for distinguishing among GAS. Fifteen pairs of throat isolates obtained from children positive for GAS before and after therapy were evaluated by conventional serotyping and by FIGE after SmaI digestion. Ten of the 15 pairs were identical by serotyping. FIGE correctly identified the 10 concordant and 5 discordant pairs. Individual clones were identified within each M type tested, including analysis performed on additional isolates of M1 and M3 obtained from the Centers for Disease Control and Prevention. This preliminary experience suggests that FIGE can successfully determine whether serial isolates from a given patient represent persistence of one strain or acquisition of a new strain of GAS and that this method might provide an alternative typing system for GAS.

Antigens, Bacterial↗
PubMed1994

An epidemic of pneumococcal disease in an overcrowded, inadequately ventilated jail.

BACKGROUND: In the United States many correctional facilities now operate at far over capacity, with the potential for living conditions that permit outbreaks of respiratory infections. We investigated an outbreak that was identified in an overcrowded Houston jail after two inmates died of pneumococcal sepsis on the same day. Outbreaks of pneumococcal disease have been rare in the era of antibiotics. METHODS: We assessed risk factors for pneumococcal disease in both a case-control and a cohort study. Ventilation was evaluated by measuring carbon dioxide levels and air flow to the living areas of the jail. The extent of asymptomatic infection was determined by culturing pharyngeal specimens from a random sample of inmates. Type-specific immunity was determined with an enzyme immunoassay. RESULTS: Over a four-week period, 46 inmates had either acute pneumonia or invasive pneumococcal disease due to Streptococcus pneumoniae serotype 12F. The jail's capacity had been set at 3500 inmates, but it housed 6700 at the time of the outbreak; the inmates had a median living area of only 34 ft2 (3.2 m2) (interquartile range, 28 to 56 ft2 [2.6 to 5.2 m2]) per person. There were significantly fewer cases of disease among inmates with 80 ft2 (7.4 m2) per person or more (P = 0.030). Carbon dioxide levels ranged from 1100 to 2500 ppm (acceptable, < 1000), and the ventilation system delivered a median of only 6.1 ft3 of outside air per minute per person (interquartile range, 4.4 to 8.5 ft3; recommended, > or = 20 ft3). The attack rate was highest among inmates in cells with the highest carbon dioxide levels and the lowest volume of outside air delivered by the ventilation system (relative risk, 1.94; 95 percent confidence interval, 1.08 to 3.48). Of underlying medical conditions, intravenous drug use was most strongly associated with disease (odds ratio, 4.50). The epidemic strain (serotype 12F) was cultured from 7 percent of the asymptomatic inmates. Of 11 case patients tested with the enzyme immunoassay, 9 (82 percent) lacked preexisting immunity to this strain. CONCLUSIONS: Severe overcrowding, inadequate ventilation, and altered host susceptibility all contributed to this outbreak of pneumococcal disease in a large urban jail.

Adult↗
PubMed1994

Emergence of drug-resistant pneumococcal infections in the United States.

OBJECTIVE: To estimate drug susceptibility patterns of Streptococcus pneumoniae in selected hospitals in the United States and to characterize the epidemiology of invasive drug-resistant pneumococcal infections. DESIGN: Minimum inhibitory concentrations (MICs) for a variety of commonly used antimicrobial drugs were determined for pneumococcal isolates submitted to the Centers for Disease Control and Prevention (CDC). Risk factors for drug-resistant pneumococcal infection were evaluated. SETTING: Hospital laboratories in the United States submitting pneumococcal isolates to the CDC between October 1, 1991, and September 30, 1992. PARTICIPANTS: A total of 544 persons with pneumococci isolated from normally sterile sites. RESULTS: A total of 13 hospitals in 12 states actively participated in an ongoing pneumococcal surveillance study. Resistance to penicillin was detected in 6.6% of isolates, including 1.3% of isolates with MICs of 2.0 micrograms/mL or more (compared with < 0.02% of isolates with MIC > or = 2.0 micrograms/mL identified by CDC surveillance from 1979 to 1987). A total of 16.4% were resistant to at least one of the following drugs or drug classes: penicillin, cephalosporins, macrolides, combination trimethoprim and sulfamethoxazole, and chloramphenicol. Six serotypes (6B, 23F, 14, 9V, 19A, and 19F) accounted for nearly 85% of strains resistant to at least one drug class. Children were more likely than adults to be infected with strains resistant to trimethoprim-sulfamethoxazole, erythromycin, or chloramphenicol. CONCLUSIONS: Emergence of drug-resistant pneumococcal infections will present critical challenges to clinicians for treating patients with pneumococcal disease. Widened and intensified surveillance is needed. These data suggest that current recommendations for use of 23-valent pneumococcal capsular polysaccharide vaccines should be aggressively promoted and that development and evaluation of new conjugate pneumococcal vaccines may be a crucial part of strategies for prevention.

Anti-Bacterial Agents↗
PubMed1994

Distribution of serotypes and antimicrobial resistance of Streptococcus pneumoniae strains isolated in Brazil from 1988 to 1992.

Forty-two serotypes were identified among 288 Streptococcus pneumoniae strains isolated from patients living in Brazil. Serotyping was determined by the capsular typing test (Quellung reaction). Types 14 (10.4%), 6B (9.8%), 23F (8.0%), 5 (7.3%), 19F (6.9%), 6A (6.0%), and 1 and 4 (4.6%) were the most commonly identified strains. Two hundred twenty (76.4%) of the strains were of serotypes that are included in the 23-valent pneumococcal polysaccharide vaccine. If vaccine-related serotypes are also considered, the proportions of coverage in the vaccine are 82.3% (if type 6B alone is added) and 85.7% (if all the vaccine-related types are considered to be cross-protecting). Decreased susceptibility to penicillin, which was identified by using the 1-microgram oxacillin disk method as a screening test, was detected in 70 (26.7%) strains. The MICs of nine antimicrobial agents were determined by using the procedures recommended by the National Committee for Clinical Laboratory Standards. Seventy (35.9%) of the strains were resistant to tetracycline, 57 (29.2%) were resistant to sulfamethoxazole-trimethoprim, 3 (1.5%) were resistant to rifampin, 2 (0.80%) were resistant to penicillin, and 1 (0.5%) was resistant to chloramphenicol. The two penicillin-resistant strains were also resistant to or had decreased susceptibilities to cephalosporins. Forty-seven (17.9%) of the strains were intermediately resistant to penicillin, 17 (8.7%) were intermediately resistant to tetracycline, 13 (6.7%) were intermediately resistant to chloramphenicol, 12 (6.1%) were intermediately resistant to erythromycin, and 6 (3.1%) were intermediately resistant to rifampin.

Brazil↗
PubMed1994

Serotypes of Streptococcus pneumoniae blood culture isolates from adults in Franklin County, Ohio.

Isolates of Streptococcus pneumoniae in cultures of blood from 258 adults seen in 10 Franklin County, Ohio, hospitals from 1991 and 1992 were serotyped. Most strains (230 [89.2%]) belonged to serotypes that are included in the current pneumococcal vaccine. An additional 16 isolates (6.2%) were immunologically related to strains with serotypes that are included in the vaccine. Only 12 isolates (4.6%) were not covered by the vaccine. The rate of mortality from pneumococcal bacteremia in adults remains high (20%). While recent studies have documented the efficacy of the pneumococcal vaccine for preventing pneumococcal bacteremia (56 to 70%), use of the pneumococcal vaccine in susceptible patients by physicians remains low (19% in Franklin County). Additional efforts need to be expended to increase the use of the pneumococcal vaccine.

Adult↗
PubMed1993

Pneumococcal polysaccharide vaccine efficacy. An evaluation of current recommendations.

OBJECTIVE: To determine pneumococcal polysaccharide vaccine efficacy in selected populations at risk for serious pneumococcal infection for whom vaccination is currently recommended and to assess duration of protection after vaccination. DESIGN: Vaccine efficacy was estimated using indirect cohort analysis to compare the proportion of pneumococcal infections caused by serotypes included in the vaccines of vaccinated and unvaccinated persons who were identified during 14 years of national surveillance. SETTING: Hospital laboratories in the United States that submitted pneumococcal isolates to the Centers for Disease Control and Prevention between May 1978 and April 1992. PARTICIPANTS: A total of 2837 persons older than 5 years who had pneumococcus isolated from blood or cerebrospinal fluid. RESULTS: Overall efficacy for preventing infection caused by serotypes included in the vaccine was 57% (95% confidence interval [CI], 45% to 66%). Efficacy among persons with diabetes mellitus was 84% (95% CI, 50% to 95%); with coronary vascular disease, 73% (95% CI, 23% to 90%); with congestive heart failure, 69% (95% CI, 17% to 88%); with chronic pulmonary diseases, 65% (95% CI, 26% to 83%); and with anatomic asplenia, 77% (95% CI, 14% to 95%). Efficacy was not documented for patients with alcoholism or cirrhosis, sickle cell disease, chronic renal failure, lymphoma, leukemia, or multiple myeloma, although sample sizes were small for these groups. Efficacy for immunocompetent persons older than 65 years was 75% (95% CI, 57% to 85%). Efficacy did not decline with increasing interval after vaccination: 5 to 8 years after vaccination it was 71% (95% CI, 24% to 89%), and 9 years or more after vaccination it was 80% (95% CI, 16% to 95%). CONCLUSIONS: Intensified efforts to improve pneumococcal vaccine coverage among certain populations for whom vaccination is currently recommended is indicated, but universal revaccination is not warranted at this time.

Adolescent↗
PubMed1993

Detection of streptococcal pyrogenic exotoxin genes by a nested polymerase chain reaction.

Severe invasive disease associated with group A Streptococcus (GAS) has recently increased in frequency. Isolates of GAS from normally sterile sites were examined for the streptococcal pyrogenic exotoxin genes spe A, spe B and spe C to determine if they play a role in this disease. Four primers for each gene were used in a nested polymerase chain reaction (PCR) configuration. The first PCR generated fragments of 818, 1106, and 801 bp, respectively, for the extotoxin genes. The second PCR generated fragments of 500, 912 and 654 bp for the spe A, spe B and spe C genes using the fragments from the first PCR as template. Of 62 strains tested, 35 (56%) contained the spe A gene, and 17 (27%) contained the spe C gene. All GAS strains studied, regardless of disease association, contained the spe B gene. These data corroborate accumulating evidence that the genes encoding pyrogenic exotoxin types B and C are not associated with severe invasive streptococcal illness including streptococcal toxic shock-like syndrome. This PCR-based gene detection system has clinical and epidemiologic applications because of its ease of performance, non-isotope labelling, high specificity and sensitivity, and lack of requirement for purified DNA.

Bacterial Proteins↗
PubMed1993

Phylogenetic analysis of some Aerococcus-like organisms from clinical sources: description of Helcococcus kunzii gen. nov., sp. nov.

16S rRNA gene sequencing studies were performed on some unusual gram-positive catalase-negative cocci of unknown taxonomic position isolated from human clinical sources. Comparative analysis of the sequence data demonstrated that the clinical isolates represent a hitherto-unknown line of descent within the low-G+C-content gram-positive bacteria. On the basis of the phylogenetic findings and the phenotypic distinctiveness of the organisms, it is proposed that they be classified in a new genus, Helcococcus, as Helcococcus kunzii sp. nov. The type strain of H. kunzii is NCFB 2900.

Bacterial Typing Techniques↗
PubMed1993

Association of phenotypic and genotypic characteristics of invasive Streptococcus pyogenes isolates with clinical components of streptococcal toxic shock syndrome.

Sixty-two invasive Streptococcus pyogenes strains, including 32 strains isolated from patients with streptococcal toxic shock syndrome (STSS), were analyzed for the following phenotypic and genotypic characteristics: M-protein type, serum opacity factor production, protease production, the presence of streptococcal pyrogenic exotoxin (Spe) genes A, B, and C, and in vitro production of SpeA and SpeB. These characteristics were analyzed for possible associations with each other as well as with clinical components of STSS. M-type 1, the most commonly isolated M-type, was significantly associated with protease production. Protease activity was significantly associated with the clinical sign of soft tissue necrosis. M-type 1 and 3 strains from STSS patients were significantly associated with the clinical signs of shock and organ involvement as well as with SpeA production in vitro. Finally, the production of SpeA was significantly associated with the clinical component of shock and organ involvement as well as with rash. These data suggest that STSS does not make up a single syndrome but, rather, that the multiple STSS clinical criteria probably reflect different phenotypic characteristics of individual S. pyogenes isolates.

Adolescent↗
PubMed1993

Identification of Leuconostoc spp. by analysis of soluble whole-cell protein patterns.

Leuconostoc spp. share several physiologic characteristics, which sometimes makes it difficult to identify these organisms to the species level. We developed a system, based on the patterns of soluble whole-cell proteins separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, that was able to discriminate between the six Leuconostoc spp. that are capable of growth at 37 degrees C. Nine unidentified Leuconostoc-like bacterial isolates that were included in the study did not fit any of the protein profiles of the type strains and may represent new Leuconostoc spp.

Bacterial Proteins↗
PubMed1992

Clusters of invasive group A streptococcal infections in family, hospital, and nursing home settings.

The spread of group A streptococcal infection to close contacts of infected persons is well recognized. With the resurgence of invasive group A streptococcal infections, there is an increased potential for clusters of patients with invasive disease. We reviewed data collected since December 1988 at the Centers for Disease Control (Atlanta) to identify clusters of infection in which one or more patients had invasive disease. Twelve family clusters were identified. Infection in index cases included the toxic shock-like syndrome and septicemia. Infection in family contacts included invasive infections, pharyngitis, or asymptomatic carriage. Most invasive disease occurred in adults, while the majority of noninvasive infections were in children. Five nosocomial clusters with spread of infection from patients to hospital personnel were documented. All index patients had the toxic shock-like syndrome; secondary infections included the toxic shock-like syndrome, pneumonia, bullous cellulitis, lymphangitis, and pharyngitis. Clusters of invasive infections also were identified in five nursing homes. Pneumonia, cutaneous infections, and the toxic shock-like syndrome occurred most commonly. Clustering by nursing home unit occurred in three outbreaks. In hospitals and nursing homes, improved infection control will likely decrease secondary spread; in families, spread of disease may be prevented by identifying and treating those harboring the organism or by chemoprophylaxis. Studies that characterize the rate of secondary infection are needed before definitive recommendations can be made.

Adult↗
PubMed1992

The spread of multiply resistant Streptococcus pneumoniae at a day care center in Ohio.

Streptococcus pneumoniae, type 23F, resistant to penicillin (MIC, 2 micrograms/mL) and multiple other antimicrobic agents, was isolated from middle ear fluid of a child with otitis media attending a day care center in Ohio. To determine the extent of spread of this strain, nasopharyngeal culture surveys were done, and 52 carriers were identified among 250 children attending the index day care center. No carriers were found among 121 children at two other day care centers in the same urban area. Use of prophylactic doses of antibiotics (P < .001) and frequent use of antibiotics (P < 0.001) were risk factors for nasopharyngeal carriage. Carriers were more likely to have had frequent otitis media episodes (P < .02) and otitis media not responsive to antimicrobial therapy (P < .001). Strategies to limit the spread of highly resistant pneumococcal strains should include encouraging judicious use of antimicrobic agents and reevaluating indications for prophylactic use of antimicrobic agents.

Adult↗
PubMed1992

Antimicrobial susceptibility patterns of common and unusual species of enterococci causing infections in the United States. Enterococcal Study Group.

We collected 705 isolates of enterococci (1 per patient) from cultures of a variety of anatomic sites from patients at eight tertiary-care hospitals in six geographic regions of the United States. A total of 632 (90%) Enterococcus faecalis, 58 (8%) E. faecium, 5 E. gallinarum, 4 E. avium, 3 E. casseliflavus, 1 E. raffinosus, and 1 E. hirae isolate and 1 biochemical variant of E. faecalis were identified; 606 (86%) of these isolates were associated with clinical infections. The most common sites of isolation were the urinary tract (402 [57%]), nonsurgical wounds (94 [13%]), the bloodstream (74 [10%]), and surgical wounds (62 [9%]). High-level resistance to gentamicin or streptomycin or both was detected in 265 (38%) of the isolates. We identified two E. faecalis isolates resistant to vancomycin (MICs, 32 and 128 micrograms/ml) and 11 beta-lactamase-producing E. faecalis isolates. E. faecium isolates were significantly more resistant than E. faecalis isolates to penicillin, ampicillin, piperacillin, imipenem, and ciprofloxacin (P less than 0.001). The MICs for the 15 non-E. faecalis, non-E. faecium enterococci indicated variable resistance to ciprofloxacin and the penicillins. Antimicrobial susceptibility patterns vary among species of enterococci, and these organisms, while commonly resistant to high-level aminoglycosides, can also acquire resistance to vancomycin or the ability to produce beta-lactamase. Because of these diverse antimicrobial resistance mechanisms, successful treatment and control of enterococcal infections with current antimicrobial agents are becoming increasingly difficult.

Adolescent↗
PubMed1991

Current trends in bacterial respiratory pathogens.

The relationship of virulence and antimicrobial susceptibility with morbidity due to bacterial respiratory pathogens is complex and evolving. Ultimately, decreasing the incidence of pneumonia due to bacterial pathogens will be dependent on successful preparation and distribution of effective vaccines. Until effective vaccines are widely available, control of a majority of respiratory infections will depend on promotion of rational therapeutic strategies. Though limited to a few specific serotypes and strains, changes in virulence of bacterial respiratory pathogens have been noted. Co-infections due to multiple respiratory pathogens may increase morbidity; however, the epidemiology of co-infections is not clear. Relationships between respiratory viruses and bacteria may exist that increase virulence of both agents, but information regarding these relationships awaits further investigation. Resistance of respiratory pathogens to the more commonly used antimicrobials, such as penicillin, erythromycin, chloramphenicol, and cotrimoxazole, is being documented globally with increasing frequency. The evolution of antimicrobic resistance, especially among strains of Streptococcus pneumoniae, the most common and deadly agent of lower respiratory tract infections, provides impetus to develop and promote effective pneumococcal vaccines and to search for new and effective antimicrobials.

Bacterial Infections↗
PubMed1991

Efficacy of Haemophilus influenzae type b polysaccharide-diphtheria toxoid conjugate vaccine in US children aged 18-59 months. Haemophilus Influenzae Vaccine Efficacy Study Group.

Vaccines prepared from the polyribosylribitol phosphate (PRP) capsule of Haemophilus influenzae b (Hib) have not consistently shown good efficacy in protecting children aged over 18 months from invasive Hib disease. To evaluate the efficacy of conjugate-PRP vaccines in this age-group, and to compare their effect with that of PRP vaccines, a post-marketing case-control study was conducted among 10,400,000 persons. Between Oct 1, 1988, and Feb 28, 1990, 75 patients with Hib disease and 161 control children between 18 and 60 months of age were enrolled. To minimise potentially confounding socioeconomic variables, controls were selected either from among patients' classmates at their day-care centre or from among family acquaintances. 9 of the 75 patients had received the diphtheria toxoid conjugate Hib vaccine more than 2 weeks before onset of illness. After adjusting for age and household crowding, the efficacy of PRP Hib vaccine was 64% (95% Cl = -20,89) and efficacy of the diphtheria toxoid conjugate Hib vaccine was 74% (95% Cl = 30,90). The study shows that the protective efficacy of this conjugate vaccine is less than ideal and highlights the need for additional post-licensing studies to confirm and expand understanding of the efficacy of these new products.

Analysis of Variance↗
PubMed1991

Antimicrobial resistance of pneumococci in children with acute lower respiratory tract infection in Pakistan.

87 strains of Streptococcus pneumoniae isolated during three winter seasons (1986-89) from the blood of children with acute lower respiratory tract infection (ALRI) in Pakistan were serotyped and tested for susceptibility to a range of antimicrobial agents. 97% of isolates were resistant to at least one antimicrobial drug. 62% had decreased susceptibility to co-trimoxazole (trimethoprim/sulphamethoxazole) (31% were fully resistant) and 39% were resistant to chloramphenicol. All isolates were susceptible to erythromycin, cefaclor, cephalothin, ceftriaxone, cefuroxime, rifampicin, vancomycin, and clindamycin. 29% of isolates were neither vaccine types nor vaccine-related types. Serotype distribution and antimicrobial susceptibility varied significantly during the three winter seasons. No single serotype was found in all three winters. The findings highlight the need for surveillance of antimicrobial resistance and serotype distribution of S pneumoniae in developing countries as a guide both to the choice of agent for treatment of pneumococcal infections, especially ALRI, and to the formulation of new pneumococcal conjugate vaccines for use in young children.

Child, Preschool↗