The IL-1B Gene Polymorphisms rs16944 and rs1143627 Contribute to an Increased Risk of Coronary Artery Lesions in Southern Chinese Children with Kawasaki Disease.

BACKGROUND: Kawasaki disease (KD) is a systemic form of self-limited vasculitis in children less than five years old, and the main complication is coronary artery injury. However, the etiology of KD remains unclear. The IL-1B polymorphisms rs16944 GG and rs1143627 AA and their diplotype GA/GA have been associated with significantly increased risk of intravenous immunoglobulin (IVIG) resistance in a Taiwanese population, but the relationship between rs16944 A/G and rs1143627 G/A and coronary artery lesions (CALs) in patients with KD has not been investigated. The present study is aimed at investigating whether the rs16944 A/G and rs1143627 G/A polymorphisms in IL-1B were associated with KD susceptibility and CALs in a southern Chinese population. METHODS AND RESULTS: We recruited 719 patients with KD and 1401 healthy children. Multiplex PCR was used to assess the genotypes of single nucleotide polymorphisms (SNPs), including two SNPs of IL-1B, rs16944 A/G and rs1143627 G/A. According to the results, no significant association was observed between the IL-1B (rs16944 and rs1143627) polymorphisms and KD risk in the patients compared with the healthy controls in our southern Chinese population. However, in further stratified analysis, we found that children younger than 12 months with the rs16944 GG and rs1143627 AA genotypes of IL-1B had a higher risk of CALs than those with the AA/AG genotypes of rs16944 and GG/AG genotypes of rs1143627 (OR = 2.28, 95% CI = 1.32-3.95, P = 0.0032, adjusted OR = 2.33, 95% CI = 1.34-4.04, P = 0.0027). CONCLUSIONS: Our results indicated that there was no association between the rs16944 A/G and rs1143627 G/A gene polymorphisms and KD susceptibility. However, the rs16944 GG and rs1143627 AA genotypes of IL-1B may significantly impact the risk of CAL formation in children younger than 12 months, which may contribute to the pathogenesis of KD. These findings need further validation in multicenter studies with larger sample sizes.

Antimicrobial resistance and prevalence of CvfB, SEK and SEQ genes among Staphylococcus aureus isolates from paediatric patients with bloodstream infections.

Staphylococcus aureus (S. aureus) is one of the most frequently isolated pathogens in neonatal cases of early and late-onset sepsis. Drug resistance profiles and carriage of toxin genes may affect the treatment and outcome of an infection. The present study aimed to determine the antimicrobial resistance patterns and frequencies of the toxin-associated genes conserved virulence factor B (CvfB), staphylococcal enterotoxin Q (SEQ) and staphylococcal enterotoxin K (SEK) among S. aureus isolates recovered from paediatric patients with bloodstream infections (BSIs) in Guangzhou (China). Of the 53 isolates, 43.4% were methicillin-resistant S. aureus (MRSA), and resistance rates to penicillin, erythromycin, clindamycin, trimethoprim/sulfamethoxazole, tetracycline, and ciprofloxacin of 92.5, 66.0, 62.3, 13.2, 20.8 and 1.9% were recorded, respectively. However, no resistance to nitrofurantoin, dalfopristin/quinupristin, rifampicin, gentamicin, linezolid or vancomycin was detected. Resistance to erythromycin, clindamycin and tetracycline in the MRSA group was significantly higher than that in the methicillin-susceptible S. aureus (MSSA) group. No significant differences in antimicrobial resistance patterns were noted between two age groups (≤1 year and >1 year). The proportion of S. aureus isolates positive for CvfB, SEQ and SEK was 100, 34.0 and 35.8%, respectively, with 24.5% (13/53) of strains carrying all three genes. Compared with those in MSSA isolates, the rates of SEK, SEQ and SEK + SEQ carriage among MRSA isolates were significantly higher. Correlations were identified between the carriage of SEQ, SEK and SEQ + SEK genes and MRSA (contingency coefficient 0.500, 0.416, 0.546, respectively; P<0.01). In conclusion, MRSA isolated from the blood of paediatric patients with BSIs not only exhibited higher rates of antimicrobial resistance than MSSA from the same source, but also more frequently harboured SEK and SEQ genes. The combination of the two aspects influenced the dissemination of MRSA among children. The present study clarified the characteristics of BSI-associated S. aureus and enhanced the current understanding of the pathogenicity and treatment of MRSA.

[Analysis of resistance tendency of bloodstream-infecting pathogens in China].

OBJECTIVE: To investigate the resistance profiles and the trend of bloodstream-infecting pathogens isolated from hospitalized patients during 2004-2010. METHODS: The bloodstream isolates were collected from 18 hospitals in 17 cities. Minimum inhibition concentrations (MIC) were determined using the agar dilution method recommended by CLSI (Clinical and Laboratory Standards Institute), and susceptibility results were analyzed according to the 2011 CLSI guideline. RESULTS: Among the 2004-2005, 2007-2008 and 2009-2010 periods, the proportions of clinical isolates were similar; 43.1% (149 isolates), 34.0% (151 isolates) and 47.5% (776 isolates) for Gram positive strains, 56.9% (197 isolates), 66.0% (293 isolates) and 52.5% (858 isolates) for Gram negative strains, respectively. The isolating rate of MRSA was 54.1% (20/37) in 2007-2008, which was the highest among the 3 periods during 2004 to 2010, while it decreased in 2009-2010 (36.5%, 62/170). The MRCNS proportions were similar across the 3 periods. One (1.8%) vancomycin-resistant Enterococcus faecium and 1 linezolid-resistant Enterococcus faecalis were found. Although the isolating rates of penicillin non-sensitive strains (oral) were similar between 2009-2010 and 2007-2008 [54.5% (6/11) and 53.9% (7/13), respectively], the resistant rates increased from 0% in 2007-2008 to 30.8% (4/13) in 2009-2010. The results were similar according to the non-meningitis criterion (IV), and the susceptibility rates decreased from 100.0% (11 isolates) in 2007-2008 to 84.6% (11/13) in 2009-2010. ESBL-harboring strains in E. coli were similar among the 3 periods during 2004 to 2010 [66.7% (30/45), 73.2% (71/97) and 67.9% (233/343), respectively]. ESBL-producing strains in Klebsilla pnuemoniae decreased year after year, 72.4% (21/29), 50.0% (18/36) and 41.1% (65/158) in 2004-2005, 2007-2008 and 2009-2010, respectively. Except that the sensitive rate of Enterobacter cloacae to ertapenem was 80% (32/40), the sensitive rates of other strains to carbapenems were still above 90% and the resistance rates were less than 5%. Acinetobacter baumannii had the highest multi-drug resistance rate (81.8%, 81/99). One strain (1.0%, 1/99) of Acinetobacter baumannii isolated in 2009-2010 was reported to be pan-resistant. CONCLUSIONS: We are facing a more serious situation of bacterial resistance. Acinetobacter baumannii resistance was most serious, usually with the characteristics of multiple drug resistance, and even pan-resistance. Carbapenems remain to be the most effective against enterobacteriaceae. Strains resistant to novel antibiotics (linezolid and tigecycline) have emerged.

[Molecular characteristics of methicillin resistant Staphylococcus aureus isolated from Chinese children].

OBJECTIVE: To investigate the molecular characteristics of methicillin-resistant Staphylococcus aureus (MRSA) isolates from Chinese children in seven cities. METHOD: A total of 134 MRSA isolates were collected from nine hospitals. Multilocus sequence typing and spa typing were analyzed by polymerase chain reaction (PCR), and staphylococcal chromosomal cassette mec (SCCmec) type was analyzed by multiplex PCR. The Panton-Valentine leukocidin (pvl) gene was also detected. RESULT: Most MRSA strains were isolated from pneumonia and skin and soft tissue infection (SSTIs) patients, accounting for 82.1%. Overall, 16 sequence types (STs) were obtained, and CC59 (51.7%) was found to be the most prevalent, which included ST 59 and ST 338, followed by ST239 (16.4%). SCCmec types II, III, IV, and V were also identified in the current study. SCCmec type IV was the most predominant type at 50.0%, followed by SCCmec type V at 23.9% and III at 23.9%. SCCmec subtypes IVa, IVc, and IVg were found among SCCmec type IV strains, whereas IVa was the main subtype at 77.6%. Twenty-six spa types were also identified, among which the predominant type was t437 (47.8%). The prevalence of pvl genes and the SCCmec type of strain was relevant, and the pvl gene positive rate was higher in SCCmec type IV and V-type strains than in SCCmec type II and III strains (58.6% vs. 14.3%, P < 0.05); there was a significant difference between them. In the strains isolated from pneumonia and SSTIs, ST59-MRSA-IVa(t437) was the predominant clone. There were five clones detected from the strains isolated from septicemia, with ST59-MRSA-IVa(t437) and ST59-MRSA-V(t437) as the main clones (57.1%). Various predominant clones existed in different regions. ST59-MRSA-IVa(t437) was the prevalent clone in the Guangzhou, Beijing, Chongqing, and Shenzhen areas, whereas ST239-MRSA-III(t037) was the prevalent clone in the Shanghai area. Fifty percent of the isolates from the Wenzhou area belonged to ST910-MRSA-V(t318), whereas three clinical strains isolated from the Shenyang region belonged to three different types. CONCLUSION: The results indicate that MRSA isolates from Chinese children are largely associated with the ST59-MRSA-IV(t437) and ST239-MRSA-III(t037) clones. These two may belong to community-acquired MRSA and hospital-acquired ones, respectively. Different prevalent clones were detected in different diseases and different regions. Therefore, there is a need to conduct further research on clinical isolates, which can guide the choice of antibiotic treatment and the examination of MRSA prevalence.

Pneumococcal serotype distribution and antimicrobial resistance in Chinese children hospitalized for pneumonia.

A prospective study was performed to determine serotype distribution and antimicrobial resistance in Streptococcus pneumoniae (S. pneumoniae) from Chinese children <5 years old meeting pneumonia criteria. A total of 3865 children were enrolled and 338 S. pneumoniae isolates were obtained. The most frequent serotypes were 19F (55.6%), 19A (13.9%), 23F (10.1%), 6B (4.7%), and 14 (3.6%). The 7-, 10- and 13-valent conjugate vaccines, respectively, covered 76.3%, 76.9%, and 92.3% of isolates. Out of the isolates, six (1.8%) were penicillin resistant. All except 1 of the isolates were resistant to erythromycin. Serotype 19A showed the highest drug resistance. The use of PCV7 has the potential to prevent a substantial number of pneumococcal infections. However, PCV13 is likely to prevent more episodes of pneumococcal disease in China because of the high rates of 19A.

[Antimicrobial resistance and penicillin resistance-associated genes of Streptococcus pneumoniae isolated from children with respiratory tract infection].

OBJECTIVE: To investigate the antimicrobial resistance and penicillin resistance-associated genes (TEM and pbp2B) of Streptococcus pneumoniae (S. pneumoniae) isolated from sputum specimens of Guangzhou children with respiratory tract infection. METHODS: E-test and Kirby-Bauer methods were applied to detect the antibiotic susceptibility of 44 strains of S. pneumoniae. PCR was used to detect resistance genes pbp2B and TEM, followed by DNA sequence analysis of pbp2B gene. The sequence results were compared to those of penicillin-susceptible S. pneumoniae R6. RESULTS: Of the 44 isolates of S. pneumoniae, only 5 (11.4%) were susceptible to penicillin. All strains were resistant to erythromycin but susceptible to ofloxacin and vancomycin. The resistance rate of the isolates to clindamycin and trimoxazole was more than 90%. The S. pneumoniae isolates showed a high susceptibility to amoxicillin, imipenem and ceftriaxone, with a resistance rate of 0, 2.6% and 3.9%, respectively. The sequence analysis showed that more than 99% nucleotide sequence of pbp2B gene of five penicillin-susceptible isolates was the same as penicillin-susceptible S. pneumoniae R6, without any amino acid replacement. Site mutation was found in the remaining 39 penicillin-nonsusceptible isolates with a nucleotide mutation rate ranging from 13.2% to 23.1% and amino acid replacement rate from 6.5% to 10.9%. The 39 penicillin-nonsusceptible isolates were classified into 4 types according to the mutation site between Ser391 and Thr492 of pbp2B: type I (n=30), type II (n=7), type III (n=1) and type IV (n=1). No TEM gene was detected in all the 44 S. pneumoniae isolates. CONCLUSIONS: The S.pneumoniae isolates from Guangzhou children with respiratory tract infection are resistant to penicillin and erythromycin. Amoxicillin and the third generation cephalosporin may be recommended for treating S. pneumoniae infection. The mutation of pbp2B gene plays an important role in the development of S. pneumoniae resistance to penicillin.

[Investigation of campylobacter jejuni infection in children with diarrhea in Guangzhou].

OBJECTIVE: To investigate the incidence of campylobacter jejuni (CJ) infection and the drug resistance of CJ in children with diarrhea in Guangzhou. METHODS: The fecal samples of 3,351 children with diarrhea between July 2005 and June 2008 were collected for CJ culture. The species of CJ strains were identified by Lior methods. The drug susceptibility tests were performed by the Kirby-Bauer method. RESULTS: Two hundred and sixty-seven CJ strains (8.0%) were isolated from 3,351 samples. The children at age of 1 month to 1 year were susceptible to CJ, accounting for 91.0%. A higher incidence of CJ infection (76.8%) was found in summer and autumn. The CJ strains were susceptible to imipenem, amikacin, cefoperazone/sulbactam, chloramphenicol, macrolides and lincomycins. Parts of CJ strains (20%-40%) were resistant to ampicillin, quinolones and ambramycin. All CJ strains were resistant to sulfamethoxazole/trimethoprim and cefditoren. Two hundred and one strains (75.3%) were CJ biotype I. CONCLUSIONS: CJ is an important pathogen of diarrhea in children from Guangzhou. CJ is resistant to some antibiotics used often in clinical practice, and so it is thus important to use antibiotics based on the results of drug susceptibility tests in children with CJ infection.

[Distribution and antibiotic resistance of pathogens isolated from children with infectious diarrhea in Guangzhou].

OBJECTIVE: To study the distribution and antibiotic resistance of the isolated pathogens from children with infectious diarrhea in Guangzhou. METHODS: The fecal samples of 2 409 children with infectious diarrhea between January 2006 and December 2007 were collected and cultured. Pathogenic bacterium were isolated and identified by biochemical and serological methods. The antibiotic susceptibilities were tested by the Kirby-Bauer method. RESULTS: A total of 448 isolates of pathogenic bacterium (18.6%) were obtained, including Shigella (n=159), enteropathogenic Escherichia coli (n=141), Salmonella (n=76), Vibrion (n=11), fungus (n=41), and C jejuni (n=20). All of isolates of the three major pathogenic bacterium, Shigella, enteropathogenic Escherichia coli and Salmonella, were susceptible to imipenem and less than 10% of the isolates were resistant to the third generation cephalosporins and beta-lactamase inhibitors. However, the isolates showed a high resistance to ampicillin and sulfamethoxazole/trimethoprim (>75%). CONCLUSIONS: Shigella, enteropathogenic Escherichia coli and Salmonella were major pathogenic bacterium of diarrhea in children from Guangzhou. The major isolates were susceptible to imipenem, the third generation cephalosporins and beta -lactamase inhibitors, but were resistant to ampicillin and sulfamethoxazole/trimethoprim.

[Cloning and sequence analysis of UreB of Helicobacter pylori isolated from children].

OBJECTIVE: To clone UreB gene of Helicobacter pylori (H. pylori) isolated from children to pGEX-4T-1 expression plasmid, and do sequence analysis. METHODS: A pair of specific primer was designed according to H. pylori UreB gene in the GenBank. Using H. pylori strains isolated from children as a template, a UreB gene was obtained by PCR. After EcoR I and Not I digestion, the PCR production was linked with pGEX-4T-1 which was digested with the same enzymes. The recombinant plasmid was transformed into E.coli BL21 and identified by double enzyme digestion and sequence analysis. The sequence results were compared with the gene sequence in the GenBank. RESULTS: A UreB gene was successfully amplified from children's H. pylori strain GZCH1. It was 1710 bp in size. The objective band was identified by double enzyme digestion. DNA sequence showed that UreB was in the correct open reading frame. The sequence comparison analysis showed that DNA and amino acid sequence identities of UreB gene with other strains were 98%. The sequence of UreB of H. pylori strain GZCH1 was submitted to GenBank (accession number:FJ455126). CONCLUSIONS: UreB of H. pylori strain GZCH1 is successfully cloned to pGEX-4T-1, which provides a basis for research of oral H. pylori vaccine.

[Prevalence of extended-spectrum beta-lactamase producing Escherichia coli in pediatric patients in China].

OBJECTIVE: To study the drug resistance profiles of extended spectrum beta lactamase (ESBL) producing Escherichia coli (E. coli) and provide guidance for pediatric clinical prescription. METHODS: 5127 strains of ESBL producing E. coli were isolated from 5 children's hospitals in Beijing, Shanghai, Chongqing, and Guangzhou. The minimum inhibitory concentration (MIC) values of 349 strains to 9 antibiotics most in use in pediatrics were measured with agar dilution method. RESULTS: The prevalent rate of ESBL producing of E. coli was 46.7%. The resistant rates to ampicillin/clavulanic acid, cefotaxime, ceftazidime, and cefepime were 23.1%, 67.2%, 24.5%, and 48.4% respectively, and the intermediate rates were 38.5%, 26.4%, 5.7%, and 19.1% respectively. The resistant rate to amikacin was 5.4%. All the strains were susceptible to imipenem. The MIC90 values of ampicillin, cefotaxime, cefepime, ciprofloxacin, and gentamicin were 256 mg/L or higher. There were differences in the resistance profile to ampicillin/clavulanic acid, cefepime, ciprofloxacin, and gentamicin among different regions. CONCLUSION: ESBL is extensively prevalent among the E. coli strains isolated from the pediatric clinic that are resistant to most antimicrobial agents except imipenem and amikacin. Regional difference exists in drug resistance to some agents exist.

[Surveillance of antibiotic resistance of Streptococcus pneumoniae isolated from hospitalized patients with pneumonia in four children's hospitals in China].

OBJECTIVE: To investigate the antimicrobial resistance of Streptococcus pneumoniae (S.pneumoniae) isolated from Chinese children with pneumonia. METHODS: Hypopharyngeal aspirate specimens were collected from hospitalized children with pneumonia who were admitted to the children's hospital located in Beijing, Shanghai, Guangzhou or Shanghai from February 16, 2006 to February 16, 2007. The minimum inhibitory concentration (MIC) of S.pneumoniae isolates against penicillin, amoxicillin, cefuroxime (sodium), ceftriaxone, erythromycin, vancomycin, ofloxacin and imipenem was determined by E-test method. RESULTS: A total of 279 S.pneumoniae isolates were obtained. Eighty-six percent of the isolates were not susceptive to penicillin, and 23.3% was resistant to penicillin. The rate of susceptibility of the isolates to amoxicillin was 92.1%, and to cefuroxime and ceftriaxone was 19.0% and 75.3%, respectively. The isolates also showed a high susceptibility to vancomycin (99.6%) and ofloxacin (97.8%). Seventeen point six percent of the isolates were not susceptive to imipenem, and most of those were intermediate. Almost of all isolates were resistant to erythromycin. There were some distinct regional differences in the susceptibility to antimicrobials tested except for erythromycin, vancomycin and ofloxacin. CONCLUSIONS: The S.pneumoniae isolates from Chinese children with pneumonia were susceptive to amoxicillin, vancomycin and ofloxacin, but were not susceptive or resistant to penicillin, cefuroxime and erythromycin. The isolates kept susceptibility to ceftriaxone and imipenem to a certain extent.

[Surveillance of antimicrobial susceptibility of Streptococcus pneumoniae and Hemophilus influenzae isolated from children in Guangzhou area between 2003 and 2004].

OBJECTIVE: To investigate the situation of antibiotic resistance of Streptococcus pneumoniae (Sp) and Hemophilus influenzae (Hi) clinical isolates from children in Guangzhou area. METHODS: The authors cultured, isolated and identified the Sp and Hi strains from nasopharyngeal secretion of patients who visited Guangzhou Children's Hospital for upper respiratory tract infection between 2003 and 2004. K-B disc diffusion and E-test for antibiotic susceptibility were performed for these clinical isolates. RESULTS: Totally 172 and 484 strains of Sp and Hi were respectively isolated from nasopharyngeal secretions in the hospital. For Sp strains, the rates of resistance to penicillin, amoxicillin/clavulanic acid, ceftriaxone, cefuroxime, cefaclor, erythromycin, tetracycline, chloramphenicol, sulfamethoxazole/trimethoprim (SMZ/TMP), clindamycin and ofloxacin were 32.0%, 11.1%, 32.6%, 18.1%, 39.5%, 82.6%, 78.5%, 24.4%, 87.2%, 69.2% and 3.1%, respectively. The penicillin non-susceptible Sp (PNSSP) isolates showed higher rates of resistance to other antimicrobial agents such as other beta-lactam antimicrobial agents, erythromycin, and SMZ/TMP than those of penicillin susceptible Sp (PSSP) isolates. More than 90% of PNSSP were multidrug resistant strains. The average rate of beta-lactamase production among 484 strains of Hi was 29.5% (143/484). For Hi isolates, the rates of resistance to ampicillin, amoxicillin/clavulanic acid, ceftriaxone, cefuroxime, cefaclor, SMZ/TMP, tetracycline, chloramphenicol, azithromycin, and ofloxacin were 40.1%, 3.4%, 4.1%, 1.9%, 5.6%, 56.2%, 52.1%, 17.4%, 2.1%, and 0.6%, respectively. CONCLUSION: The antimicrobials resistant Sp and Hi isolated from children with respiratory tract infection in the area have become a severe problem. The rate of resistance to penicillin of Sp had been decreased compared with the last three years, but the rate of resistance to ceftriaxone of Sp increased, and the multidrug resistance rates of PNSSP was rather high. PNSSP was characterized by a multidrug-resistance to erythromycin, tetracycline and SMZ/TMP. beta-lactamase production and ampicillin resistance among the Hi isolates from children in the area had increased generally during the period 2003 - 2004. The Hi isolates were more susceptible to the second and the third generation cephalosporins, amoxicillin/clavulanic acid and azithromycin.

[Serotype distribution and resistance to beta-lactams of Streptococcus pneumoniae isolated from children in Beijing, Shanghai and Guangzhou, 2000 - 2002].

OBJECTIVE: The present study was designed to investigate the situation of serotype distribution and beta-lactam antibiotics resistance of Streptococcus pneumoniae (S. pneumoniae) isolated from Chinese children, and to further understand the significance of vaccine for preventing infection caused by the bactria and controlling the resistance to antibiotics. METHODS: Nasopharageal swab specimens were collected from randomly selected less than 5-year-old out-patients with upper respiratory infection in Beijing, Shanghai and Guangzhou, 2000 - 2002. Capsular typing was performed by the Quellung reaction tested using a simplified chessboard system for typing of S. pneumoniae. The coverage rate of the 7-valent pneumococcal conjugate vaccine (4, 6B, 9V, 14, 18C, 19F and 23F) was calculated. Antibiotic susceptibility was determined by E-test MIC method for beta-lactam antibiotics (penicillin, amoxicillin/clavulanic acid, cefaclor, cefuroxime and ceftriaxone). RESULTS: Totally 625 pneumococcal strains were typed. Serogroup 19, including 121 strains, was the most frequent serogroup observed (19.4%). Other frequently observed serotypes/serogroups in decreasing order of frequency were serotype/serogroups 23 (15.4%), 6 (13.3%), 14 (6.6%) and 15 (4.3%). Of all these isolates, about 57.6% (360/625) were in the 7-valent conjugate vaccine. Only 1, 6 and 12 strains were serotypes/serogroups 4, 9 and 18, respectively. The coverage rate for the 7-valent vaccine of penicillin nonsusceptible S. pneumoniae (PNSP) was higher than penicillin susceptible S. pneumoniae (PSSP) (73.2% and 46.1%). Serogroups 19 and 23, without other serotypes/serogroups, were significantly associated with PNSP (serogroup 19 accounted for 29.1% of PNSP and 12.2% of PSSP; serogroup 23 accounted for 23.8% of PNSP to 9.2% of PSSP). Overall, 140 strains (22.4%) could not be typed by using the chessboard system, and 117 strains (18.7%) were identified as other 28 kinds of serotype/serogroup. The strains showed different resistance change for beta-lactam antibiotics according to different serotype/serogroup during the three years. CONCLUSIONS: Serotype/Serogroup 19, 23, 6, 14 and 15 were the common types among the pneumococcal strains isolated from Chinese children. Serogroups 19 and 23 were significantly associated with PNSP. The 7-valent pneumococcal conjugate vaccine could cover most of the islotes.

[Carrier rate of Streptococcus pneumoniae and susceptibility thereof to antimicrobial drugs among children in China: a surveillance study in Beijing, Shanghai, and Guangzhou 2000-2002].

OBJECTIVE: To investigate the carrier rate of Streptococcus pneumoniae and the susceptibility of S. pneumoniae to 10 different antimicrobial drugs among children in China. METHODS: Nasopharageal swab specimens were collected from randomly selected 3578 out-patients with upper respiratory infection aged 1 month to 5 years in Beijing, Shanghai, and Guangzhou 2000-2002 so as to isolate S. pneumoniae. The susceptibility of these strains to erythromycin and beta-lactam antibiotics (penicillin, amoxicillin/clavulanic acid, cefaclor, cefuroxime and ceftriaxone) was determinated by E-test MIC method, and the susceptibility to chloramphenicol, tetracycline, sulfamethoxazole/trimethoprim and ciprofloxacin was determinated by disk diffusion method. RESULTS: A total of 892 strains of S. pneumoniae were isolate from the 3578 children with a carrier rate of 24.9% (9.0%-36.0%). 634 isolates of S. pneumoniae were tested to examine their susceptibility to chloramphenicol, 199 to ciprofloxacin, and 887 to the other 8 antimicrobial drugs. The insusceptibility rate of S. pneumoniae to penicillin was 39.9%, and the resistance rate was 6.4%. The resistance rate to cefaclor was 20.4%. The insusceptibility rate to cefuroxime was 19.0%. The susceptibility rate to amoxicillin/clavulanic acid was 98.5% and that to ceftriaxone was 97.2%. More than 80% of the isolates were resistant to erythromycin, tetracycline, and sulphamethoxazole/trimethoprim. Chloramphenicol resistance was less common (32.3%) than the resistance to other non-beta-lactam antibiotics, except for ciprofloxacin to which the resistance rate was 2.0%. The national insusceptibility rates for beta-lactam antibiotics did not vary significantly during the three years with the widest varying range of 5.1% for penicillin (38.1%-43.2%). Each of the three cities had their different varying patterns of antimicrobial susceptibility, especially for beta-lactam antibiotics. Multi-drug resistance was common (88.7%). Strains of S. pneumoniae insusceptible to penicillin were significantly more common than those susceptible to penicillin (99.1% vs. 78.8%, chi(2) = 50.36, P < 0.001), and strains of S. pneumoniae insusceptible to erythromycin were significantly more common than those susceptible to erythromycin too (95.8% vs. 17.1%, chi(2) = 360.26, P < 0.001). CONCLUSION: Antimicrobial resistant S. pneumoniae has already become a serious problem in China. Ongoing surveillance study on the antimicrobial resistance of S. pneumoniae is necessary for appropriate antimicrobial use in clinical work and modification of medical strategies for people's health.

[Surveillance of antimicrobial susceptibility of Haemophilus influenzae isolates from children in Beijing, Shanghai, and Guangzhou 2000 - 2002].

OBJECTIVE: To investigate the situation of antibiotic resistance of Haemophilus influenzae isolates from Chinese children. METHODS: Eight hundred and ninety-eight strains of H. influenzae isolated from randomly selected pediatric out-patients in Beijing, Shanghai and Guangzhou 2000 approximately 2002 underwent determination of antibiotic susceptibility by E test MIC method for beta-lactam antibiotics (ampicillin, amoxicillin/clavulanic acid, ceftriaxone, cefuroxime, and cefaclor) and KB disc diffusion method for chloramphenicol, tetracycline, sulfamethoxazole/trimethoprim (SMZ/TMP), azithromycin, and ciprofloxacin. RESULTS: The average rate of beta-lactamase production among these isolates was 12%. The MIC50 and MIC90 of ampicillin were 0.25 microg/ml and 4 microg/ml respectively for the 898 isolates, 88% of the isolates were susceptible to ampicillin and 10.6% was resistant. There was no beta-lactamase negative strains among the ampicillin intermediately-susceptible and resistant strains. All the isolates were susceptible to amoxicillin/clavulanic acid, ceftriaxone, cefuroxime and azithromycin. 96.1% of the H. influenzae isolates generally remained susceptible to cefaclor with a MIC50 of 1.5 microg/ml and a MIC90 of 3 microg/ml, and 99% of the isolates were susceptible to ciprofloxacin. The susceptibility rate to tetracycline of the isolates from Beijing and Shanghai areas were 57% and 61% respectively, both lower than the susceptibility rates of the isolates from Guangzhou (81%), while the resistant rate to SMZ/TMP of the isolates from Beijing was 35%, lower than those of the isolates from Guangzhou (47%) and Shanghai (54%). The resistant rate to ampicillin was 7.7% in 2000 and was increased to 14.5% in 2002. 34.5% of all the isolates were susceptible to 8 antimicrobial agents while 12.8% was multi-drug resistant. 58.5% of the isolates were distributed in five major antimicrobial resistance profiles in which SMZ/TMP resistance (29.8%) was the most prevalent, followed by SMZ/TMP and tetracycline combined resistance (12.5%) and tetracycline resistance (9.4). The ampicillin non-susceptible isolates had higher resistant rates to cefaclor (23.5%), tetracycline (63.3%), SMZ/TMP (74.5%) and chloramphenicol (63.3%) than the ampicillin susceptible strains (1.6%, 51.4%, 11.1% and 4.9% respectively). CONCLUSION: Beta-lactamase production and ampicillin resistance among the isolates from Chinese children are increasing generally during the period 2000 approximately 2002. There is variation of resistance among different regions. There are strong correlations between ampicillin resistance and resistance to cefaclor, chloramphenicol, and tetracycline among the H. Influenzae isolates.