Epidemiology of penicillin resistance in Streptococcus pneumoniae isolates in Kayseri, Turkey

Objective   To determine the penicillin resistance and serotype distribution of Streptococcus pneumoniae strains and to identify clonal relationships of isolates resistant to penicillin by means of pulsed-field gel electrophoresis (PFGE).
Methods   In total, 193 S . pneumoniae strains were isolated from clinical specimens between November 1997 and January 2000. Susceptibility testing was carried out by E test, and serotyping by the Quellung reaction. Clonal relationship was analyzed by using PFGE with sma I endonuclease.
Results   Of the S. pneumoniae isolates, 23% were intermediately resistant to penicillin. There were no high-level resistant pneumococci. The majority of isolates intermediately resistant to penicillin were of serogroups/serotypes 19, 23, 14 and 1, in descending order of frequency. There were eight major clones in strains intermediately resistant to penicillin. It was seen that serogroups in the 23-valent polysaccharide vaccine, 7-valent, 9-valent, and 11-valent vaccine formulations caused 92%, 75%, 78% and 87% of pneumococcal diseases in our region, respectively.
Conclusion   Penicillin resistance in S. pneumoniae is relatively uncommon in Kayseri. All vaccine formulations can prevent the majority of pneumococcal diseases, and there is genetic heterogeneity in intermediately penicillin-resistant pneumococci in this region.     

Pneumococcal acute otitis media in children

Objectives   To evaluate the clinical and laboratory findings of Streptococcus pneumoniae acute otitis media in children during a 1 year period.
Methods   From October 1995 to September 1996, 113 children aged 2 months to 14 years (median 18 months), with S. pneumoniae acute otitis media were studied. Susceptibility testing was performed by the Kirby-Bauer method and the E- test, and serotyping by the Quellung reaction.
Results   E- test assays detected five isolates (4.4%) to be highly resistant to penicillin and 13 (11.5%) that had intermediate resistance. All isolates were found to be susceptible to vancomycin, rifampicin and cefotaxime. In total, 25 isolates (22.1%) were resistant to one or more drugs. Fifty per cent of the penicillin-resistant or intermediately resistant S. pneumoniae isolates were resistant to multiple drugs, whereas only 2.1% of the penicillin-susceptible isolates were resistant to multiple drugs. The predominating serogroups of the isolates with reduced susceptibility to penicillin were the 19 (61.1%), 9 (16.7%), 23 (11.1%), 6 (5.5%) and 14 (5.5%) whereas those of the susceptible isolates were the 19 (26.3%), 14 (13.7%), 3 (11.6%), 6 (11.6%), 9 (8.4%), 1 (5.3%) and 12 (5.3%).
Conclusions   Streptococcus pneumoniae isolates from children with acute otitis media were penicillin-insensitive in 15.9%. The multiresistant S. pneumoniae isolates belonged to serogroups: 19 (45.4%), 9 (27.3%), 6 (18.2%) and 23 (9.1%).     

Evolution of Streptococcus pneumoniae serotypes and antibiotic resistance in Belgium—update (1994–98)

Objective To follow the evolution of capsular types and resistance of Streptococcus pneumoniae , isolated from deep sites.
Methods More than 100 Belgian laboratories permanently collect S. pneumoniae strains isolated from puncture specimens (blood, cerebrospinal fluid, middle ear fluid, etc.) and forward them to the reference center in Leuven, in order to determine the capsular serogroups and types (SGTs) and their resistance.
Results From 1994 to 1998, the 5486 S. pneumoniae strains examined belonged to 39 of the 46 currently identified SGTs. The 10 most frequent SGTs accounted for 78.9% of the isolates, and 97% of all isolates belonged to SGTs included in the 23-valent vaccine. Overall mortality of patients with pneumococcal bacteremia or meningitis was 9.7%, and 23.8% in patients over 80 years. From 1994 to 1998, resistance to penicillin (P) increased from 7.6% to 14.2%, to tetracycline (T) from 14.9% to 28.0%, and to erythromycin (E) from 22.9% to 31%. Triple resistance (PTE) increased from 0.9% in 1994 to 6.6% in 1998. Five SGTs (6, 9, 14, 19 and 23) accounted for 50% of the isolates, but for > 90% of the penicillin-resistant or erythromycin-resistant isolates.
Conclusions Resistance of S. pneumoniae to penicillin, erythromycin and tetracycline is steadily increasing and is concentrated in five serotypes included in the 23-valent pneumococcal vaccine. Increasing resistance and high mortality of invasive infections are an incentive to vaccinate vulnerable groups.     

A cross-sectional survey of the prevalence of Streptococcus pneumoniae nasopharyngeal carriage in Belgian infants attending day care centres

Nasopharyngeal carriage is a major factor in the transmission of pneumococcal disease. The aim of this study was to determine the prevalence of asymptomatic nasopharyngeal carriage of Streptococcus pneumoniae and the distribution of serogroups and serotypes in children aged 3-36 months attending day care centres in Belgium. A single nasopharyngeal swab was cultured from 467 children attending 30 different day care centres between December 2000 and March 2001. S. pneumoniae isolates were serotyped and their antibiotic susceptibilities assessed by disk diffusion. The overall nasopharyngeal carriage rate for S. pneumoniae was 21% in the 467 children. None of the commonly accepted risk factors studied was associated significantly with carriage. Capsular serotypes isolated were 19F (27.3%), 6B (20.2%), 23F (19.2%), 19A (10.1%), 6A (7.1%), 14 (5.1%) and others (11.0%). Theoretical coverage by the seven-valent (serotypes 4, 6B, 9V, 14, 18C, 19F and 23F) pneumococcal conjugate vaccine was 73.7%. Fourteen (14.1%) of 99 strains were non-susceptible to penicillin, 48 (48.5%) to tetracycline and 61 (61.6%) to erythromycin. Theoretical coverage by the seven-valent pneumococcal conjugate vaccine was 93% for the penicillin-resistant serotypes, 69% for the tetracycline-resistant serotypes and 75% for the erythromycin-resistant serotypes. Use of the seven-valent pneumococcal conjugate vaccine could potentially reduce nasopharyngeal carriage of the antibiotic-resistant strains.     

Inferring the potential success of pneumococcal vaccination in Italy: serotypes and antibiotic resistance of Streptococcus pneumoniae isolates from invasive diseases

To evaluate the potential impact of antipneumococcal vaccination in Italy, Streptococcus pneumoniae isolates from invasive disease were collected from 65 laboratories in the years 1997-2000. Of the 503 isolates examined, 15% were from children <5 years and 34% from adults > or = 65 years. The most frequent serogroups were, in ranking order, 14, 19, 6, and 23. Overall, 93.8% of the isolates belonged to serogroups enclosed in the 23-valent polysaccharide vaccine. Among children isolates, serotypes 14, 6B, and 23F comprised 60% of the isolates; overall, 72% of the isolates belonged to serotypes included in the heptavalent conjugate vaccine. Penicillin nonsusceptible isolates (10%) belonged to a limited number of serogroups, being more common in serogroups 19 and 9 and in the nonvaccine serogroups 24 and 35. Erythromycin-resistant isolates (29%) belonged to several serogroups, more frequently to serogroups 14, 6, and 19. Both vaccines are potentially able to prevent the majority of resistant infections in the respective age groups in Italy.     

Prevalence and patterns of resistance of Streptococcus pneumoniae strains isolated from carriers attending day care centers in the area of Athens

The prevalence and patterns of Streptococcus pneumoniae resistance to antibiotics was examined in 146 nasopharyngeal carrier strains obtained during April and May, 1997, from 382 healthy children attending eight day care centers (DCCs) in the area of Athens. Reduced susceptibility to at least one antibiotic was found in 32.6% as follows: penicillin 11.4% (intermediate), cefotaxime 0.8% (intermediate), trimethoprim-sulfamethoxazole 22.7%, erythromycin 13.6%, tetracycline 11.4%, chloramphenicol 8.3%. Most of the nonsusceptible to penicillin isolates belonged to serogroups 23, 9, and 19. Multidrug resistance was detected in 11.4% of S. pneumoniae isolates including five penicillin nonsusceptible serogroup 23 strains. More than half of the multidrug resistant strains were susceptible to penicillin and belonged to serogroups 6 (4), 23 (1), 19 (1), and 1(1). Strains that belonged to the same serogroup/serotype and had identical resistance patterns appeared to cluster in some DCCs. Antibiotic use in the previous month was associated with reduced susceptibility to penicillin (p = 0.007) and multidrug resistance (p = 0.012). In conclusion, a moderate prevalence of reduced susceptibility to penicillin in pneumococcal carrier strains was found in our community. Multidrug resistance was common and was often associated with susceptibility to penicillin. Several distinct patterns of resistance were observed, suggesting the spread of resistant clones to our country.     

Antimicrobial resistance and serotypes of nasopharyngeal strains of Streptococcus pneumoniae in Brazilian adolescents

The aim of this study was to describe the frequency of antimicrobial-resistance and serotypes of nasopharyngeal pneumococcal isolates from adolescents. Clinical data and nasopharyngeal specimens for culture were collected from 1,013 adolescents as a part of a population-based study. A total of 83 isolates of Streptococcus pneumoniae were identified (8.2%). Seventy-four of the 83 isolates were serotyped. The median age of the 83 adolescents colonized by pneumococci was 14 years (mean 14 +/- 2.2 yrs); 55.4% were males. Intermediate resistance to penicillin was detected in 7.2% (6/83). No strain showed high resistance to penicillin. All isolates were susceptible to clindamycin, chloramphenicol, rifampin, and vancomycin; 37.3%, 18.1%, and 4.8% were resistant to trimethoprim-sulfamethoxazole, tetracycline, and erythromycin, respectively. The most frequent serotypes (5-10% of strains each) were 6B, 6A, 23F, and 18C among 28 serotypes/serogroups identified; 18.9% of the strains were nontypeable (NT). Intermediate resistance to penicillin was detected in serotypes 6B, 14, and NT. The rate of resistance to penicillin of nasopharyngeal isolates is low considering data from other studies about invasive strains recovered from children in Brazil. Serotype patterns are similar, except for type 14, which was unusually infrequent.     

Extremely high incidence of macrolide and trimethoprim-sulfamethoxazole resistance among clinical isolates of Streptococcus pneumoniae in Taiwan

From January 1996 to December 1997, 200 isolates of Streptococcus pneumoniae recovered from 200 patients treated at National Taiwan University Hospital were serotyped and their susceptibilities to 16 antimicrobial agents were determined by the agar dilution method. Sixty-one percent of the isolates were nonsusceptible to penicillin, exhibiting either intermediate resistance (28%) or high-level resistance (33%). About two-fifths of the isolates displayed intermediate or high-level resistance to cefotaxime, ceftriaxone, cefepime, imipenem, and meropenem. Extremely high proportions of the isolates were resistant to erythromycin (82%), clarithromycin (90%), and trimethoprim-sulfamethoxazole (TMP-SMZ) (87%). Among the isolates nonsusceptible to penicillin, 23.8% were resistant to imipenem; more than 60% displayed resistance to cefotaxime, ceftriaxone, cefepime, and carbapenems; 96.7% were resistant to erythromycin; and 100% were resistant to TMP-SMZ. All isolates were susceptible to rifampin and vancomycin. The MICs at which 50% and 90% of the isolates were inhibited were 0.12 and 1 microgram/ml, respectively, for cefpirome, and 0.12 and 0.25 microgram/ml, respectively, for moxifloxacin. Six serogroups or serotypes (23F, 19F, 6B, 14, 3, and 9) accounted for 77.5% of all isolates. Overall, 92.5% of the isolates were included in the serogroups or serotypes represented in the 23-valent pneumococcal vaccine. The incidence of macrolide and TMP-SMZ resistance for S. pneumoniae isolates in Taiwan in this study is among the highest in the world published to date.     

Carriage of Antibiotic-Resistant Streptococcus pneumoniae in Greek Infants and Toddlers

The prevalence, resistance patterns and serotypes of antibiotic-resistant Streptococcus pneumoniae strains recovered from Greek carriers under 24 months of age were studied. From February 1997 to April 1998, nasopharyngeal cultures were performed in 1269 children (ages 2–23 months, median 11 months) living in various areas of central and southern Greece. Resistance (including both intermediate and resistant isolates) to one or more antimicrobial agents was found in 132 of the 421 (31%) Streptococcus pneumoniae isolates, as follows: penicillin, 9% intermediate, 7.6% resistant; cefotaxime, 5.2% intermediate, 0.5% resistant; erythromycin, 0.7% intermediate, 18.1% resistant; clindamycin, 0.2% intermediate, 12.4% resistant; tetracycline, 0.7% intermediate, 16.4% resistant; chloramphenicol, 12.4% resistant; and trimethoprim-sulfamethoxazole, 3.8% intermediate, 14.3% resistant. The MICs of penicillin for 66% of the penicillin-nonsusceptible pneumococci were 1–4 μg/ml. Multidrug resistance was found in 64% of penicillin-nonsusceptible and 37% of penicillin-susceptible strains. Sixty-two percent of the penicillin-susceptible, multidrug-resistant strains belonged to serotype 6B and were resistant to all five non-β-lactam agents tested. This notable serotype 6B resistance pattern was described for the first time in a previous study performed from December 1995 to February 1996 in the city of Patras, southwestern Greece. Seventy-two percent of antibiotic-resistant isolates belonged to serotypes 6B, 9V, 14, 18C, 19F and 23F. These results document the spread of resistant pneumococcal strains in central and southern Greece, many of which are multidrug resistant.     

A common clone of erythromycin-resistant Streptococcus pneumoniae in Greece and the UK

Objective  To investigate the possible genetic relationship among erythromycin-resistant Streptococcus pneumoniae strains isolated in Greece and the UK.
Methods  During 1995–97, 140 S. pneumoniae strains were isolated from clinical specimens submitted to the microbiology departments of the two main children's hospital in Athens. All erythromycin-resistant strains were further studied with respect to the presence of genes encoding for the two major mechanisms of macrolide resistance, their serotypes, and pulsed-field gel electrophoresis (PFGE) types, in comparison to a previously characterized UK erythromycin-resistant clone.
Results  Eleven of the 140 isolates (7.9%) were resistant to erythromycin; nine of these were susceptible to penicillin. Serotyping allocated seven, three and one isolates to serotypes 14, 19F and serogroup 6, respectively. The mef A gene was detected in seven isolates (five serotype 14 and two serotype 19F), erm B in two (one serotype 19F and the serogroup 6 isolate), whilst in the remaining two isolates no resistance gene could be detected by polymerase chain reaction (PCR). Pulsed-field gel electrophoresis of genomic DNA showed that five Greek serotype 14 isolates belonged to the same chromosomal type as the serotype 14 erythromycin-resistant UK clone.
Conclusions  The present study showed that erythromycin resistance among the S. pneumoniae isolates was mostly owing to the efflux mechanism and suggested a possible clonal spread of serotype 14 erythromycin-resistant S. pneumoniae strains between Greece and the UK.     

Distribution of Streptococcus pneumoniae serotypes responsible for penicillin resistance and the potential role of new conjugate vaccines in New Caledonia

Invasive pneumococcal disease is a significant cause of morbidity and mortality worldwide. The aim of this study was to establish the serotypes responsible for pneumococcal disease and the serotypes responsible for penicillin resistance in Noumea, New Caledonia. Isolates of Streptococcus pneumoniae from all body sites referred to the Microbiology Department of the Pasteur Institute in New Caledonia between May 1999 and May 2001 had serotyping and susceptibility testing performed. Basic demographic data on patients were also collected. A total of 298 isolates were included in the study. The most common serotypes were types 1 (20%), 23F (10%), 12F (8%), 19F (8%), and 6B (5%). The serotype distribution differed significantly with age, site of collection, and ethnicity. Overall, 280 of 298 (94%) of the isolates had serogroups that are included in the 23-valent vaccine. However, only 14 of 20 (70%) of the isolates associated with invasive disease from children younger than 5 years of age and 26 of 113 (23%) of invasive isolates from patients more than 5 years of age were included in the new 7-valent conjugate vaccine. Overall, reduced susceptibility to penicillin was found in 43 of 298 (14.4%) of the isolates, with 13% falling into the intermediate resistance category and only 5 (2%) being high-level resistant. A higher prevalence of penicillin resistance occurred in younger age groups and in European patients and involved specifically certain serotypes. The 7-valent conjugate pneumococcal vaccine has potential benefit for the New Caledonian population under 5 years of age and should be considered for future vaccines schedules.     

Increase in Penicillin Resistance Rates in Belgium due to Clonal Spread of a Penicillin-Resistant 23F Streptococcus pneumoniae Strain

 In 1994 a sudden increase in penicillin resistance was observed in Belgium among invasive pneumococci. To determine whether this increase was due to clonal spread of a resistant strain or to de novo acquisition of penicillin resistance, pneumococci of capsular types 23F, 19, 14, 9, and 6, isolated in 1993 and 1994, were analyzed by capsular serotyping and DNA macrorestriction analysis, resolved by pulsed-field gel electrophoresis. Furthermore, pneumococcal isolates from northern France, a region with a high prevalence of penicillin resistance, and from southern Belgium, a region with a low but increasing prevalence of penicillin resistance, were analyzed. The rate of resistance of invasive pneumococci to penicillin increased from 2.3% in 1993 to 7.6% in 1994. Pneumococcal serotype 23F represented 26.7% of the penicillin-resistant isolates in 1993 and 40.4% in 1994, while the prevalence of serotype 23F decreased from 10.9% in 1993 to 8.8% in 1994. In 1994 up to 35.8% of serotype 23F isolates were penicillin resistant. The Belgian penicillin-resistant 23F isolates from 1994 were genetically closely related to the French 23F penicillin-resistant isolates and, as clones were clearly distinct from the other serotypes as well as from the penicillin-susceptible 23F isolates. These data demonstrate the important contribution of the clonal spread of a penicillin-resistant pneumococcal strain in the overall increase of penicillin resistance in our country.     

Genetic relatedness of resistant and multiresistant Streptococcus pneumoniae strains,recovered in the Athens area,to international clones

The prevalence of resistance to antibiotics was examined among 318 Streptococcus pneumoniae strains isolated during 1998 and 1999 in a children's hospital in Athens. The rate of resistance to penicillin was 25.8% (intermediate 22%, resistant 3.8%); 42.5% of the strains were resistant to > or = 1 antibiotic and 20% were multidrug resistant. Resistance to penicillin was lowest in invasive strains (8.3%) and highest in ear isolates (31%). A review of the same microbiology laboratory's records revealed that there has been a gradual increase in penicillin resistance since 1988-1989, when it was 5%. Capsular types were determined for 77 strains resistant to > or = 1 antibiotic, and 69 (90%) of them belonged to the following five serotypes: 19F, 14, 9V, 23F, and 6B. Seventy-five strains were analyzed by pulsed-field gel electrophoresis (PFGE) and 59/75 (79%) shared five electrophoretic types. The largest cluster consisted of 19 serotype 19F strains, of which 18 were nonsusceptible to penicillin and most were multidrug resistant and shared a common and distinct electrophoretic pattern not resembling any known clone. A group of 17 strains that were nonsusceptible to penicillin belonged to serotypes 9V (10), 14 (6), and 19F (1) and shared a common PFGE type similar to the international clone Spain9V-3. Seven serotype 23F strains, of which five were multidrug resistant, belonged to the international clone Spain23F-1. Among the strains susceptible to penicillin but resistant to non-beta-lactam antibiotics, the largest cluster consisted of 13 isolates resistant to erythromycin that belonged to serotype 14 and shared an electrophoretic pattern characteristic of the clone England14-9. Finally, three serotype 6B strains were penicillin susceptible and multidrug resistant and had features similar to the Mediterranean 6B clone. The introduction and spread of several antibiotic-resistant international clones accounts at least in part for the increase in pneumococcal resistance observed in recent years in the Athens metropolitan area.     

Serotype profile and antibiotyping of Streptococcus pneumoniae strains isolated from nasal carriage in pediatric patients

The aim of this study was to determine the serotype profile and antibiotyping of Streptococcus pneumoniae from nasal isolates in children. Nasopharyngeal swab samples obtained from 125 children were cultivated and screened for the presence of S. pneumoniae. Strains were identified according to standard microbiological methods. The isolates were serotyped by the Quellung reaction and resistance patterns were determined by the microdilution method according to NCCLS guidelines. Results indicate an overall pneumococcal carriage rate of 24% (n = 30). The most commonly isolated serotypes were 23F (20%), 6B (20%) and 14 (13%). 73% of isolates were resistant at least to one of the tested antibiotics. 47% of the strains were consistently resistant to penicillin and the serotypes 6B and 23F were frequently associated with this marker. 60% of the strains were resistant to doxycycline, 37% to trimethoprim/sulfamethoxazole and clindamycin, 30% to erythromycin, 23% to cloramphenicol, 7% to ceftriaxone and 3% to cefepime. All strains were sensible to ofloxacin, rifampin and vancomycin. The most common combined resistance patterns were PNC-ERI-TMP/SMX-DOX-CLO-CLI (16.59%) and PNC-DOX (13.27%). The results obtained in this study will allow to orient the empiric therapy for pneumococcal infections and a rational use of antibiotics in clinical practice, as well as the application of an appropriate vaccination program specially adapted to the serotypes more frequently found in children.     

Prevalence of serotypes and molecular epidemiology of Streptococcus pneumoniae strains isolated from children in Beijing, China: identification of two novel multiply-resistant clones

Three-hundred and seventy-six strains of Streptococcus pneumoniae isolated from clinical specimens and nasopharyngeal swabs from children at daycare centers and hospitals in Beijing China, between January 1997 and March 1998, were serotyped. Twenty-seven different serotypes were identified. The most prevalent serotypes in the carriage isolates were 6A, 19F, 23F, and 15 and were found in 66.8% of cases. Serotype data indicate that 51.8% of carrier strains would be included in the 11-valent conjugate vaccine formulation, while inclusion of vaccine-related serotypes, increased the potential vaccine coverage to 79.4%. Serotypes 7, 6B, 23F, 19F, 15, and 3 accounted for 62% of clinical strains, with 70% vaccine-related serotypes. DNA fingerprinting of 47 penicillin resistant and 71 penicillin-susceptible/macrolide-resistant strains by BOX polymerase chain reaction (PCR), pulsed-field gel electrophoresis (PFGE), and penicillin binding protein (PBP)-fingerprinting identified two novel clones: one a serotype 23F multiresistant clone resistant to penicillin, tetracycline, erythromycin, clindamycin, and variably resistant to chloramphenicol and trimethoprim-sulphamethoxazole; and the second a multiresistant penicillin-susceptible, macrolide-resistant serotype 6A clone, highly resistant also to tetracycline, clindamycin, and trimethoprim-sulphamethoxazole. The macrolide resistance determinant in 89% of erythromycin-resistant strains tested (penicillin-susceptible and penicillin-resistant) was the erm gene, both the erm and mef genes were simultaneously found in 6%, and mef alone in 3.4%. The data demonstrates that macrolide resistant strains in China include clonal strains and strains with dual mef and erm resistance determinants.     

Characterization of penicillin intermediate serotypes of Streptococcus pneumoniae carried by human immunodeficiency virus-infected adults and healthy children in Uganda

There are little data on the genetic relatedness between antibiotic-resistant pneumococcal isolates colonizing the Ugandan population. Penicillin-intermediate pneumococci of serogroups or serotypes rarely or not previously reported as being penicillin nonsusceptible were selected out of 166 isolates representing 26 capsular serogroups or serotypes isolated from Ugandan children in 1995 and human immunodeficiency virus (HIV) infected Ugandan adults in 2004-2005. Pairs of penicillin-intermediate pneumococci of the same serogroup or serotype present in both patient populations were characterized further by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). Seven such pairs of isolates were found and included serogroups 7, 11, 15B/C, and 16 as well as serotypes 13, 21, and 35B. PFGE of these seven pairs showed no clonality between serogroups or serotypes, and clonality only within serogroup 11 and serotype 13. MLST of the 14 individual isolates revealed 13 different sequence types (STs), 11 of which had not previously been recorded. Comparisons with all known STs revealed that most of these strains were related only to strains of the same serotype in other countries, with these related strains frequently also being penicillin intermediate. These findings suggest that penicillin nonsusceptibility in Uganda is likely due to the introduction of antibiotic-resistant pneumococcal clones into Uganda rather than development of resistance within the country.     

Antimicrobial susceptibility of Streptococcus pneumoniae from children attending day-care centers in a central Italian city

Objective: To undertake a survey of nasopharyngeal carriage of Streptococcus pneumoniae , which reflects strains causing infection, in 100 children under 3 years of age attending day-care centers in Frosinone, a city near Rome.
Methods: Fifty-three unique isolates of S. pneumoniae , isolated from 41 of the children tested, were tested for antimicrobial susceptibility to penicillin, cefotaxime, erythromycin, clindamycin, tetracycline, chloramphenicol and trimethoprim-sulfamethoxazole.
Results: Resistance rates were as follows: penicillin, 20.7% (15% intermediate; 5.7% resistant); trimethoprim-sulfamethoxazole, 64.2%; erythromycin, 64.2%; clindamycin, 30.2%; tetracycline, 32.1%; and chloramphenicol, 3.8%. Except for three intermediate strains, all strains were susceptible to cefotaxime. Only five strains were susceptible to all of the antibiotics tested. An unusual finding of this study was that 23 of the 34 erythromycin-resistant strains were penicillin susceptible, whereas erythromycin-resistant strains found in other countries are predominantly penicillin resistant as well. In addition, 18 of the 34 erythromycin-resistant strains were susceptible to clindamycin. Serogroups 6, 14, 19 and 23 accounted for 84.9% of the isolates.
Conclusions: These data show that carriage of antibiotic-resistant pneumococci in children under 3 years of age is high in Frosinone, Italy. Information on resistance rates in pneumococcal disease in different age groups and on prevalence of drug resistance in other parts of the country is urgently needed.     

Unique variations of pbp2b sequences in penicillin-nonsusceptible Streptococcus pneumoniae isolates from Korea

pbp2b gene alterations were analyzed in 102 clinical isolates of Streptococcus pneumoniae (30 penicillin susceptible, 23 intermediate, and 49 resistant) from Korea. On the basis of PBP2B amino acid sequences, penicillin-nonsusceptible isolates of S. pneumoniae belonged to six groups, and 76% of the isolates in groups I to IV showed the same divergent block of amino acid alterations. Thirteen isolates (group II) also possessed a divergent block that was identical to that of Streptococcus oralis. The pbp2b genes of most Korean isolates showed novel mosaic mutations due to horizontal gene transfer. The Thr252 --> Ala substitution, previously thought to be associated only with penicillin-nonsusceptible strains, was also found in three penicillin-susceptible strains. On the basis of their pbp2b nucleotide sequences, all penicillin-nonsusceptible isolates can be detected by multiplex PCR, which can be used as a novel method for detection of antibiotic-resistant pneumococcal strains in clinical specimens.     

Characteristics of the major etiologic agents of bacterial meningitis isolated in Poland in 1997-1998

Bacterial meningitis remains a major cause of morbidity and mortality worldwide, especially in children. In this paper, we present the results of the first two years (1997-98) of activity of the National Reference Centre for Bacterial Meningitis (NRCBM) on the etiologic agents of bacterial meningitis in Poland. Of the 220 isolates sent to the NRCBM, the most frequently identified was Neisseria meningitidis (n = 90, 40.9%), followed by Haemophilus influenzae (n = 58, 26.4%), and Streptoccus pneumoniae (n = 46, 20.9%). Of the meningococcal isolates, 88.9% belonged to serogroup B and 10.0% to serogroup C, and the most prevalent serotype was 22 (43.3%). Most meningococci were highly sensitive to penicillin; however, 10% of them had decreased susceptibility to penicillin. More than 90% of H. influenzae belonged to serotype b, and all were susceptible to third generation cephalosporins and chloramphenicol. A broad distribution of serotypes was found among pneumococcal isolates, of which the most common were serotypes 3 and 8. Penicillin nonsusceptible isolates constituted 13% of all pneumococcal isolates. Three of the resistant pnemococci belonged to serotype 23F. Data presented in this paper demonstrate the current epidemiological situation of bacterial meningitis in Poland.     

Molecular epidemiological characteristics of pneumococcal meningitis in children

The molecular epidemiological characteristics of pneumococcal meningitis in children were studied. Pneumococcal isolates were characterized by serotyping and two genotyping methods, BOX fingerprinting and restriction fragment end labeling, to evaluate whether clonal strains were present within the serotypes or serogroups. During a 17-year period, 68 children admitted to the Sophia Children's Hospital were diagnosed with meningitis due toStreptococcus pneumoniae. Pneumococcal isolates from 44 patients were still available for analysis. All strains were susceptible to penicillin. Serotypes/ serogroups 14,19, 6, and 18 represented 56% of all isolates. The results of the molecular typing methods demonstrate the absence of clonal relatedness between isolates from patients with pneumococcal meningitis.