Susceptibility to antimicrobial agents in isolates from invasive Streptococcus pneumoniae in Colombia]

A study was done to determine the patterns of susceptibility to antimicrobial agents in isolates of Streptococcus pneumoniae that caused invasive disease diagnosed in children under the age of 5 in Colombia between 1994 and 1996, as well as to establish the distribution of the capsular types of the resistant isolates. The analysis was done using 324 isolates obtained during the performance of the National Serotyping Protocol for S. pneumoniae carried out in Bogotá, Medellín, and Cali, Colombia, between July 1994 and March 1996. Of the 324 isolates, 119 (36.7%) showed diminished susceptibility to at least one antimicrobial agent, including 39 (12%) that showed diminished susceptibility to penicillin. Of these 39 resistant to penicillin, 29 showed intermediate resistance and 10 showed high resistance. Nine isolates (2.8%) showed resistance to ceftriaxone, 80 (24.7%) to the combination of trimethoprim and sulfamethoxazole (TMS), 49 (15.1%) to chloramphenicol, and 31 (9.6%) to erythromycin. Resistance to two antimicrobial agents was observed in 31 isolates (9.6%); multiple resistance was found in 22 (6.7%). These 22 multiresistant isolates all showed resistance to TMS. The most frequent associations were penicillin, TMS, and erythromycin (5 cases); penicillin, chloramphenicol, TMS, and erythromycin (4 cases); penicillin, ceftriaxone, chloramphenicol, and TMS (3 cases); and penicillin, ceftriaxone, chloramphenicol, TMS, and erythromycin (3 cases). The most frequent serotypes in the penicillin-resistant isolates were: 23F (53.8%), 14 (25.6%), 6B (7.7%), 9V (5.1%), 19F (5.1%), and 34 (2.6%). The most frequent serotypes in the isolates resistant to antimicrobial agents other than penicillin were: 5 (37.5%), 23F (7.5%), 14 (18.8%), and 6B (13.8%). This difference in the distribution of the serotypes was statistically significant (P < 0.0001). The study results indicate the need to maintain active surveillance of antibiotic susceptibility patterns in order to avoid resistance in S. pneumoniae and to provide timely information to change practices regarding prescribing and consuming antimicrobial agents.     

Nasopharyngeal carriage of Streptococcus pneumoniae in healthy children: implications for the use of heptavalent pneumococcal conjugate vaccine

We assessed the prevalence of Streptococcus pneumoniae serotypes in the nasopharynx of healthy children, antimicrobial susceptibility patterns, risk factors for carriage, and the coverage of heptavalent pneumococcal conjugate vaccine. In 2,799 healthy infants and children, the S. pneumoniae carrier rate was 8.6% (serotypes 3, 19F, 23F, 19A, 6B, and 14 were most common). Most pneumococci (69.4%) were resistant to one or more antimicrobial classes. The rate of penicillin resistance was low (9.1%); macrolide resistance was high (52.1%). Overall, 63.2% of the isolates belonged to strains covered by the heptavalent pneumococcal vaccine. This percentage was higher in children <2 years old (73.1%) and in those ages 2-5 years (68.9%). Sinusitis in the previous 3 months was the only risk factor for carrier status; acute otitis media was the only risk factor for the carriage of penicillin-resistant S. pneumoniae. Most isolated strains are covered by the heptavalent conjugate vaccine, especially in the first years of life, suggesting that its use could reduce the incidence of pneumococcal disease.     

肺炎链球菌对大环内酯类的耐药机制研究

目的 探讨台州医院肺炎链球菌临床分离株的耐药性及对红霉素的耐药机制,为临床用药提供依据.方法 收集临床分离的肺炎链球菌31株,运用K-B纸片法及VITEK细菌鉴定仪检测其对抗菌药物的药敏谱;通过纸片法筛选对大环内酯类抗菌药物(红霉素)的耐药表型,PCR扩增红霉素耐药基因:ermB、mefA,并送测序鉴定.结果 K-B法纸片药敏结果显示,肺炎链球菌临床分离株主要对红霉素、磺胺甲噁唑/甲氧苄啶和四环素耐药,耐药率分别为:100.0％、64.5％、32.2％;未发现有对青霉素、万古霉素及替考拉宁耐药的菌株;31株肺炎链球菌临床分离株耐药表型均为组成型耐药;31株红霉素耐药菌株的基因均为ermB(+)/mefA(+),测序结果正确.结论 台州医院肺炎链球菌临床分离株对红霉素耐药率高,erm基因介导的靶修饰作用和mef基因介导的外排泵机制的共同作用,是主要的耐药机制.     

Antibiotic sensitivity of Streptococcus pneumoniae in Tunisia: results of a multicenter study (1998-1999)

We report the results of a multicenter tunisian study, performed over a two-year period (1998-1999), to determine the susceptibility pattern of Streptococcus pneumoniae in our country. A total of 146 S. pneumoniae were collected during the study period. 76 were recovered from adults and 70 from children. 53% of isolates have decreased susceptibility to penicillin, 24% with low level resistance, and 11% with high level resistance. Amoxicillin and cefotaxime decreased susceptibility rates were: 12% (low level resistance exclusively). and 14% (10% with low level resistance and 4% with high level resistance) respectively. Strains isolated from children, showed higher resistance to b lactams than those isolated from adults. Resistance rates to other antibiotics were as follow: erythromycin 28%, choramphenicol 14%, cyclins 23%, thrimethoprim-sulfamethoxazole 28% and rifampin 1%. No vancomycin resistant strain was found. The acquire resistance rates of Streptococcus pneumoniae in Tunisia are worrying, essentially for penicillin and erythomycin. Amoxicillin and cefotaxime have conserved a good activity.     

Molecular epidemiology and genetic diversity of pneumococcal carriage among children in Beni State, Bolivia

During 2007, a study of pneumococcal carriage in children was performed in two towns (Trinidad and Riberalta) in the Beni region of the Bolivian Amazon basin. Little has previously been reported regarding the epidemiology of pneumococcal carriage in Bolivia, and no multilocus sequence typing (MLST) of pneumococcal isolates from this region has previously been documented. A pneumococcal carriage rate of 34% was identified. Of 53 Streptococcus pneumoniae isolates that survived transportation for serotyping, antibiotic susceptibility testing and MLST, the commonest serotypes were 6A (9%), 34 (8%), 4 (6%), 9A (6%), 10A (6%), 19A (6%), 23F (6%) and 38 (6%); overall, 26 different serotypes were identified. Antibiotic susceptibility testing by Etest demonstrated high levels of susceptibility to penicillin (93%), erythromycin (98%), vancomycin (100%), chloramphenicol (100%), tetracycline (96%) and trimethoprim/sulfamethoxazole (co-trimoxazole) (85%). MLST identified that the majority (57%) of viable isolates belonged to previously unrecognised sequence types that are currently unique to Bolivia.     

Nasopharyngeal carriage of community-acquired, antibiotic-resistant Streptococcus pneumoniae in a Zambian paediatric population.

The emergence of antibiotic-resistant Streptococcus pneumoniae is an international health problem. Apart from South Africa few data on pneumococcal resistance are available for sub-Saharan Africa. This study examines the nasopharyngeal carriage and prevalence of antibiotic resistance in pneumococci isolated from 260 Zambian children aged < 6 years. Pneumococci were isolated from 71.9% of the children; the odds of carrying organisms were twice as high among children < 2 years of age compared with older children. Antibacterial resistance was found in 34.1% of the isolates; resistance to tetracycline, penicillin, sulfamethoxazole + trimethoprim, and chloramphenicol occurred in 23.0%, 14.3%, 12.7%, and 3.9% of the isolates, respectively. Only 4% of the isolates were resistant to three drugs. High-level resistance was found in all isolates resistant to tetracycline; but only intermediate level penicillin resistance was found. A total of 11.1% of the isolates demonstrated intermediate resistance to sulfamethoxazole + trimethoprim. Children aged < 6 months were less likely to carry antibiotic-resistant organisms. Antibiotic resistance in S. pneumoniae appears to be an emerging public health problem in Zambia, and the national policy for the empirical treatment of pneumococcal meningitis and acute respiratory tract infections may need to be re-evaluated. The establishment of ongoing surveillance to monitor trends in pneumococcal resistance should be considered.     

Aggregated antibiograms and monitoring of drug-resistant Streptococcus pneumoniae

Community-specific antimicrobial susceptibility data may help monitor trends among drug-resistant Streptococcus pneumoniae and guide empiric therapy. Because active, population-based surveillance for invasive pneumococcal disease is accurate but resource intensive, we compared the proportion of penicillin-nonsusceptible isolates obtained from existing antibiograms, a less expensive system, to that obtained from 1 year of active surveillance for Georgia, Tennessee, California, Minnesota, Oregon, Maryland, Connecticut, and New York. For all sites, proportions of penicillin-nonsusceptible isolates from antibiograms were within 10 percentage points (median 3.65) of those from invasive-only isolates obtained through active surveillance. Only 23% of antibiograms distinguished between isolates intermediate and resistant to penicillin; 63% and 57% included susceptibility results for erythromycin and extended-spectrum cephalosporins, respectively. Aggregating existing hospital antibiograms is a simple and relatively accurate way to estimate local prevalence of penicillin-nonsusceptible pneumococcus; however, antibiograms offer limited data on isolates with intermediate and high-level penicillin resistance and isolates resistant to other agents.     

Characteristics of Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis and Staphylococcus aureus isolated from the nasopharynx of healthy children attending day-care centres in the Czech Republic

Nasopharyngeal carriage of potential pathogens was studied in 425 healthy 3- to 6-year-old children attending 16 day-care centres (DCCs) in nine Czech cities during the winter 2004-2005. The overall carriage of pathogens was 62.8% (Streptococcus pneumoniae, 38.1%; Haemophilus influenzae, 24.9%; Moraxella catarrhalis, 22.1%; Staphylococcus aureus, 16%). An age-related downward trend was observed for colonization with respiratory pathogens in contrast to Staph. aureus whose carriage was significantly higher among older children. The following serotypes of colonizing S. pneumoniae were the most predominant: 23F (20.6%), 6A (15.1%), 6B (12.7%), 18C (7.8%), 15B and 19F (6% each). The majority (94.3%) of H. influenzae isolates were non-typable; among capsulated isolates, serotype b was not found. Decreased susceptibility to penicillin was determined in 3% of pneumococci; 4.6% of H. influenzae strains and 85.1% of M. catarrhalis strains produced beta-lactamase. As for non-beta-lactam antibiotics, pneumococci resistant to trimethoprim-sulphamethoxazole were the most common (15.7%) among the attendees.     

广东省人群多重耐药金葡菌的携带及耐药性分析

目的 调查广东省部分人群(动物从业人员和一般人群)的多重耐药金葡菌(multidrug-resistant S.aureus,MDRSA)携带情况,并分析菌株的耐药性.方法 对研究对象进行问卷调查和鼻拭子采样,对金葡菌进行药敏试验,分析方法采用x2检验.结果 动物从业人员中金葡菌、MDRSA、甲氧西林耐药金葡菌(methicillin-resistantS.aureus,MRSA)的携带率均高于对照人群(分别为13.3％ vs9.3％;9.5％ vs 3.4％;7.0％ vs 1.4％;均有P＜0.01).金葡菌对青霉素、克林霉素、四环素和红霉素的耐药率较高,MDRSA主要耐药模式是同时对克林霉素、红霉素、四环素耐药.除了青霉素外,动物从业人员金葡菌对各类抗生素的耐药率均高于对照人群;MRSA菌株对各类抗生素的耐药率均高于甲氧西林敏感金葡菌.结论 本研究提示职业性动物接触可能导致从业人员感染耐药细菌.