Multicentre study of the molecular epidemiology, serotypes and antimicrobial susceptibility patterns of invasive Streptococcus pneumoniae invasive isolated from children in the Ille de France area.

Between January 1997 and April 2002, 73 consecutive invasive strains of Streptococcus pneumoniae were isolated from children under 16 years of age in four hospitals in suburban Paris. Their genetic diversity was investigated by serotyping and analysis of pulsed-field gel electrophoresis restriction patterns. Antibiotic susceptibility patterns were analysed by disk susceptibility testing and determination of minimal inhibitory concentrations. The genetic basis of macrolide resistance was investigated by polymerase chain reaction. Studies of penicillin and vancomycin tolerance were performed for each strain. Despite the high prevalence (45.2%) of penicillin-nonsusceptible Streptococcus pneumoniae, resistance to amoxicillin (1.4%) was rare, and no strain was resistant to cefotaxime. Overall, 4.1% of pneumococcal strains were resistant to penicillin. Penicillin or vancomycin tolerance was not detected in any of the 73 strains studied. Of the erythromycin-resistant strains (48%), all but one carried the ermB gene. No strains showing a decreased susceptibility to ciprofloxacin (MIC, >4 mg/l) or overexpressing an efflux pump inhibited by reserpine were isolated. The serotypes found, in order of frequency, were as follows: 18C, 14, 6B, 19F, 19A, 9V, 23F, 1, 7F, 9A, 38. Strains of penicillin-nonsusceptible Streptococcus pneumoniae belonged predominantly to serotypes 14, 6B, 9V, 9A, 23F, 19F and 19A. The seven-valent conjugated vaccine covered 85.5% of the serogroups isolated in children under 2 years of age and 65.6% of the serogroups identified in children over 2 years of age. The genetic analysis showed a high identity for some serotypes, such as 14/9V, 6B and 23F. The use of the seven-valent conjugated vaccine is a critical measure to prevent invasive pneumococci infections in children in the Ille de France area.

[Epidemiology and antimicrobial resistance of Streptococcus pneumoniae strains isolated in Ile de France area during 2001]. / Epidémiologie et résistance aux antibiotiques de Streptococcus pneumoniae en Ile de France en 2001.

OBJECTIVE: The authors wanted to assess the level of Streptococcus pneumoniae antibiotic resistance in Ile de France. METHOD: In 2001, 637 clinical strains of S. pneumoniae were prospectively collected from 32 microbiology laboratories. RESULTS: Fifty one percent of strains were isolated from children under 15 years of age and 49% from adults. In children, 76% of strains came from otitis media, 20% from blood culture, in adults most strains (92%) came from blood culture. The overall prevalence of non-susceptible penicillin pneumococci was 61% higher in children (73%) than in adults (50%). Among the non-susceptible penicillin pneumococci 21.8% were resistant (CMI > 1 mg/l). Strains with decreased susceptibility to amoxicillin and cefotaxime were 38% and 17% respectively. Resistant strains to these two drugs (CMI > 2 mg/l) were rare 2.6% and 0.4% respectively. Among other antimicrobial agents, rate of resistance was 63% to erythromycin, 47% to cotrimoxazole, 40% to tetracycline, and 23% to chloramphenicol. The most frequent serogroups were serogroups 19 and 14, respectively 23% and 18%. Serotypes included in heptavalent vaccine covered 90% of children strains under 2 years of age. CONCLUSIONS: The prevalence of resistance to penicillin was high in children particularly in otitis media pus (76%).

[Apropos of a case of Streptococcus pneumoniae salpingitis, epidemiology of female genital pneumococcal infections]. / A propos d'un cas de salpingite à Streptococcus pneumoniae, épidemiologie des infections génitales de la femme à pneumocoque.

BACKGROUND: Pneumoccocci were sometimes isolated from female genital tract specimens, usually without any clinical signification. However few cases of female pneumococcal genital infections were previously reported. CASE REPORT: We describe an additional report of salpingitis, occurring in a 35-years old female early after installation of an intra-uterine device. DISCUSSION: Data collected by the National Reference Center for Pneumococci show that 0.9% of the strains documented in the past five years (1992 to 1996) were isolated from the female genitals tract. Most of these infections are caused by S. pneumoniae belonging to the serotypes 1 or 3. About 20% of the strains displayed a reduced sensitivity to penicillin. Although genital infections caused by S. pneumoniae and the neonatal colonisation with the maternal strain are rare, their potential occurrence should not be neglected. Thus, in order to limit the risks of such infections, an antibiotic treatment should immediately started following the detection of a pneumococcal genital carriage.

In-vitro bacteriostatic activity of levofloxacin and three other fluoroquinolones against penicillin-susceptible and penicillin-resistant Streptococcus pneumoniae.

The purpose of this study was to investigate the in-vitro bacteriostatic activity of levofloxacin in comparison with that of ofloxacin, sparfloxacin and ciprofloxacin against 205 strains of Streptococcus pneumoniae (101 penicillin-susceptible, 51 penicillin-intermediate and 53 penicillin-resistant). The isolates were provided between September 1996 and October 1996 by French hospitals participating in the National Co-operative Survey of Pneumococcal Infections. The determination of MICs (mg/L) was made by the agar dilution method. The MIC50 and MIC90 values of the four fluoroquinolones for the three classes of S. pneumoniae (penicillin-susceptible, penicillin-intermediate and penicillin-resistant) were not significantly different. In contrast, the differences in in-vitro activity observed among the four fluoroquinolones against the 205 strains allowed them to be separated into three groups: sparfloxacin (MIC50/90 0.25 mg/L); ciprofloxacin and levofloxacin (MIC50 0.5 and 1 mg/L respectively, MIC90 1 mg/L); and ofloxacin (MIC50 1 mg/L, MIC90 2 mg/L). A total of 204 of the strains had a levofloxacin MIC between 0.25 mg/L and 1 mg/L, and only one of the 205 strains was highly resistant (MIC 16 mg/L). Whatever the level of susceptibility to penicillin, the relative bacteriostatic activity was, in descending order of activity, sparfloxacin, levofloxacin/ciprofloxacin and ofloxacin. These results suggest levofloxacin has potential for the treatment of pneumococcal infections.

[Streptococcus pneumoniae: serotypes, invasive and antibiotic resistant strains. Current situation in France]. / Streptococcus pneumoniae: sérotypes, souches invasives et résistantes aux antibiotiques. Situation actuelle en France.

OBJECTIVES: Anti-pneumococcal antibiotic therapy has reduced morbidity and mortality of pneumococcal infections, but this success has retarded wide application of vaccination. The emergence and worldwide diffusion of antibiotic-resistant strains raises an important public health problem. The current situation requires determining the respective roles of antibiotic therapy and vaccine immunoprophylaxy. The aim of this work was to examine the data collected by the French National Pneumococci Registry. METHODS: The Nation Surveillance Network for Pneumococcal Infections was initiated in France in 1984. With this registry, it has been possible to follow regularly the evolution of serotypes and their sensitivity to antibiotics in 34,130 strains received from 1984 to 1996 and to compare these results with the clinical data. RESULTS: Serotyping the invasive strains has shown that the relative frequency of these serotypes has been stable: the 23-valence pneumococca vaccine provided good serotype coverage from 1984 to 1996 (87.2% of the invasive strains isolated in 1996 belonged to the vaccine types). Penicillin-resistant pneumococci comprised 3.8% of the strains, isolated in 1987 and 42.8% of those isolated in 1996. Two-thirds of these penicillin-resistant pneumococci had high-level resistance and an equivalent percentage were multiresistant. The consequences of resistant strains on antibiotic therapy for pneumonia, acute otitis and meningitis is discussed. CONCLUSION: Bacterio-clinical surveillance networks provide regular epidemiological data aimed at better use of antibiotics and the promotion of vaccination campaigns. In the future, the vaccination of children under 2 years of age with new conjugated polysaccharide vaccines should be an essential step in the global strategy against pneumococcal infections. The vaccinal formula of such a pediatric vaccine would contain 10 valences, defined according to the serotype results we have obtained: 1, 3, 4, 6, 7, 9, 14, 18, 19, 13. This vaccine would cover 86.1% of the invasive strains and 90.7% of the strains isolated from children with acute otitismedia.

[Development of resistance to beta-lactams and other antibiotics of pneumococci isolated from acute otitis media in France: statement of the National Reference Center 1995-1996]. / Evolution de la résistance aux bêtalactamines et aux autres antibiotiques des pneumocoques isolés d'otites moyennes aiguës en France: bilan du Centre national de référence 1995-1996.

POPULATION AND METHODS: During 1995 and 1996, 393 and 566 strains of Streptococcus pneumoniae, isolated from acute otitis media, were respectively sent to the National Reference Center for Pneumococci by its corresponding centers. RESULTS: The resistance rates for 1995 and 1996 were respectively: for penicillin: 65.4 and 70.3% (18.6 and 24.9% of intermediately resistant strains, 46.8 and 45.4% of fully resistant strains), for erythromycin: 57.5 and 68.5%, for tetracycline: 43.2 and 42.6%, for trimethoprim-sulfamethoxazole: 47.5 and 50.9%. Minimal inhibitory concentrations (MICs) of various betalactams were determined against a representative sample of strains (n = 99). CONCLUSION: Amoxicillin, cefpodoxime and cefuroxime MICs remained low against numerous penicillin resistant strains, indicating that these three oral antibiotics (in combination with clavulanate for amoxicillin) have a useful potential for the treatment of acute otitis media when risk factors for pneumococcal penicillin-resistant infections are detected.

[Presumptive tests and molecular hybridization for the identification of untypable strains of Streptococcus pneumoniae]. / Tests présomptifs et hybridation moléculaire pour l'identification des souches de Streptococcus pneumoniae non typable.

Five different methods for identification of pneumococci (optochine susceptibility, bile solubility, Slidex Pneumo-kit, Phadebact Pneumococcus test, AccuProbe DNA test) were evaluated with a total of 280 Streptococcus pneumoniae non typable strains. 189 strains were identified as pneumococci according to the AccuProbe test results. Among these, 180 strains (95.2%) were optochine sensitive (d > or = 12 mm). Bile solubility was seen in 125 (66.1%) of the pneumococci. Immunological identifications were respectively positive for 67 and 56 among 140 strains. By comparison with the DNA/RNA reassociation method, the poor sensitivities and specificities of the presumptive identification tests are actually demonstrated for pneumococcal non typable strains. Thus, the AccuProbe DNA test is seen as the only adequate method for identification of such strains.

In-vitro killing activity of combinations of beta-lactam agents with aminoglycosides against penicillin-resistant pneumococci.

Streptococcus pneumoniae has developed resistance to almost every antibacterial agent used in clinical practice, including the most active beta-lactams. This has led to the proposed use of drug combinations. The aim of this study was to determine the efficacy of combinations of beta-lactam agents (cefotaxime or imipenem) with aminoglycosides (gentamicin, netilmicin or amikacin) against pneumococci showing high-level resistance to penicillin and streptomycin and/or kanamycin. All tested combinations were bactericidal and synergic despite the weak concentrations of antibiotics used. Our results suggest that combinations of beta-lactam agents with aminoglycosides may be useful for treating infections by penicillin-resistant pneumococci located outside the central nervous system.

Septicaemia caused by phenotypic variants of group A streptococci.

Clinical isolates (115) of Streptococcus pyogenes responsible for septicaemia were investigated to determine whether invasiveness may be correlated with a large variety of strains, or concerns only particular phenotypes. Irrespective of their clinical origin, the strains studied displayed seven of the ten biotypes described within this species. As already observed in a series of strains isolated from pharyngitis, a restricted association between M-types and biotypes was demonstrated; each M-type corresponded to a sole biotype. However, the proportion of biotypes 3, 5 and 7 was higher in the septicaemia series than in the pharyngitis series, with a larger variety of M-types and with more non-typable strains. Despite these differences, the restricted associations between these characters were concordant in both series. These results demonstrate that streptococcal septicaemias appear to be caused by a wide variety of strains, suggesting that multiple factors may be involved in the invasiveness of the bloodstream during streptococcal infections.

In vitro killing activities of antibiotics at clinically achievable concentrations in cerebrospinal fluid against penicillin-resistant Streptococcus pneumoniae isolated from children with meningitis.

We evaluated the in vitro killing activities of ceftriaxone, imipenem, vancomycin, gentamicin, fosfomycin, and rifampin, alone and in combination, against 26 Streptococcus pneumoniae strains (penicillin G MICs, > 0.125 to 2 micrograms/ml) isolated from the cerebrospinal fluid of children with meningitis. The antibiotics were tested at clinically achievable concentrations in cerebrospinal fluid. After 5 h of incubation, imipenem was the most effective drug. None of the combinations had synergistic activity. Killing by beta-lactam antibiotics or vancomycin was enhanced by the addition of gentamicin, reduced by the addition of rifampin, and unaffected by the addition of fosfomycin.

[Resistance of Streptococcus pneumoniae to penicillin. "Bacteriological" resistance/"clinical" resistance]. / La résistance de Streptococcus pneumoniae à la pénicilline résistance "bactériologique"/résistance "clinique".

From January 1988 to December 1992, 143 Streptococcus pneumoniae strains have been isolated at a significant level from 136 patients hospitalized in the pulmonary care unit of CHI Créteil. The clinical presentations were: 83 pneumonia (P), 48 acute bronchitis (B) and 12 colonizations (C). Fourteen strains were found to be penicillin resistant (MIC > 0.125 mg. l-1): 11 P, 2 B, 1 C. Two patients were lost of view after the beginning of the treatment: a pneumonia (Serotype 23F, MIC = 2 mg. l-1) and a bronchitis (Serotype 23F, MIC = 2 mg. l-1). Treatment was pristinamycine for one and amoxicilline alone or associated to clavulanic acid for the other 13. We observed the failure of the treatment in two. A pneumonia (Serotype 23, MIC = 2 mg. l-1) was treated before hospitalization by josamycine (3 days), then cefpodoxime (4 days) and amoxicillin-clavulanic acid (1.5 gr/d during 7 days). Healing was obtained with the increase to 3 gr/d. The other failure was a pneumonia without improvement after 11 days with 3 gr/d of amoxicilline. The treatment was stopped during 5 days and a protected brushing was performed. A Streptococcus Pneumoniae (Serotype 23F, MIC = 8 mg. l-1) was isolated. The clinical status rapidly improved with erythromycine (3 gr/d) to which the strain was susceptible. "Bacteriological" Resistance to penicillin is demonstrated (10 percent in our sample, 17 percent in France during 1991). However amoxicillin to a sufficient dosage is still enough ("Clinical" Resistance < 1 percent in our sample) for the treatment of respiratory infections except when the MIC is at a high level.

[In vitro antibacterial activity of pristinamycin against penicillin resistant Streptococcus pneumoniae]. / Activité antibactérienne in vitro de la pristinamycine sur Streptococcus pneumoniae résistant à la pénicilline.

Pristinamycin, a member of streptogramin family, is the association of two groups (components I and pristinamycin II A) which have a high synergistic activity. Given the increasing rates of penicillin resistance in Streptococcus pneumoniae in many countries, and in particular of strains exhibiting multiple resistance to commonly used antibiotics, it was interesting to study the in vitro activity of pristinamycin against penicillin resistant S. pneumoniae (47 strains) and compare it with that of erythromycin. All strains were isolated from otitis media. Minimal inhibitory concentrations (MICs) were determined by an agar dilution technique using Mueller-Hinton medium supplemented with 5% horse blood. An inoculum of 10(4)-10(5) CFU per spot was delivered by a Steers replicator. This study showed that, among the 47 penicillin resistant strains, 29 (61.7%) were resistant to erythromycin but none of them were resistant to pristinamycin. The good in vitro activity of pristinamycin against S. pneumoniae could be of particular interest in cases of infections with multiresistant strains.

In-vitro antibacterial activity of RP 59500, a semisynthetic streptogramin, against Streptococcus pneumoniae.

The in-vitro activity of the new streptogramin RP 59500 was determined against 100 strains of Streptococcus pneumoniae. In all, 48 erythromycin-sensitive strains and 52 erythromycin-resistant strains were tested by an agar dilution method (MIC determination), 20 strains (eight erythromycin-sensitive and 12 erythromycin-resistant) were tested by a broth microdilution technique (MIC and MBC determination) and ten strains (two erythromycin-sensitive and eight erythromycin-resistant) were tested for bactericidal kinetics. The study showed that RP 59500 had good bacteristatic and bactericidal activity against both erythromycin-sensitive and erythromycin-resistant strains. On the basis of these results, and because the number of erythromycin-resistant strains of S. pneumoniae isolated in France has increased steadily since 1985, RP 59500 might be useful for the treatment of pneumococcal infections and warrants further investigation.

Antimicrobial resistance in Streptococcus pneumoniae: an epidemiological survey in France, 1970-1990.

The antimicrobial resistance of Streptococcus pneumoniae was surveyed in 1970-1990 at Saint Joseph and Broussais hospitals in Paris (3,279 isolates) and in 1984-1990 at the National Reference Center for Pneumococci (NRCP) in Créteil (8,128 isolates). All isolates were tested for susceptibility and serotyped. At St. Joseph and Broussais hospitals, the rate of resistance to tetracycline increased from 14% in 1970 to 46.5% in 1978 and then decreased to approximately 20% in 1988-1990. Resistance to chloramphenicol appeared in 1972; its frequency remained at less than 10% until 1990. Resistance to macrolides was first detected in 1976, increased to 20% in 1984, and reached 29% in 1990. Among strains submitted to the NRCP, resistance to penicillin (MIC, greater than or equal to 0.1 mg/L) remained infrequent (less than or equal to 1.1%) between 1984 and 1986 but then increased steadily, reaching 12% in 1990. The frequency of high-level resistance to penicillin (MIC, greater than 1 mg/L) among penicillin-resistant pneumococci increased from 13% in 1988 to 48% in 1990. Compared with other serotypes, the penicillin-resistant serotype isolated most frequently (23F, 49.3%) was more often highly resistant to penicillin and was more often multiresistant.