Thirty-one strains of Klebsiella pneumoniae (including 10 duplicates) from 21 septicemic pediatric patients (age, <2 months) were studied during a 4-month period (June to October 1996) in which the fatality rate was 62% (13 of 21). These isolates identified by the API 20E system yielded the same biotype. Pulsed-field gel electrophoresis experiments revealed the same clone in 31 strains. The isolates were multidrug-resistant but were still susceptible to ciprofloxacin, imipenem, and cefoxitin. A 135-kb plasmid was harbored in all of the isolates. No transconjugants were obtained that were resistant to ampicillin, cefotaxime, tetracycline, or gentamicin. Isoelectric focusing for ␤-lactamases was performed on all strains, and three bands with pIs of 5.4, 7.6, and 8.2 were obtained. Of these, the pI 8.2 ␤-lactamase had an extended-spectrum ␤-lactamase phenotype. PCR amplification of both TEM-and SHV-type genes was obtained. The sequence analysis of the SHV PCR product indicated a mutation corresponding to the SHV-5 ␤-lactamase.Klebsiella pneumoniae is an important hospital-acquired pathogen with the potential of causing severe morbidity and mortality in pediatric patients. Several outbreaks of infection caused by K. pneumoniae isolates that are simultaneously resistant to broad-spectrum cephalosporins and aminoglycosides have been widely reported (8,9,18,21). Some of these multidrug-resistant isolates produce extended-spectrum ␤-lactamases (ESBLs) that are able to hydrolyze expanded-spectrum cephalosporins (e.g., ceftriaxone, cefotaxime, and ceftazidime), aztreonam, and related oxyimino-␤-lactams. Most of these enzymes are TEM-or SHV-type ␤-lactamases in which the substitution of one or more amino acids has altered the configuration of the active site (7,14,19). Most of the plasmids determining ESBLs are large (Ն80 kb) and encode multiple resistances (10). Little is known about the ESBL-producing Enterobacteriaceae in Mexico (23). The present work is a characterization of 31 ESBL-producing K. pneumoniae isolates from a nosocomial outbreak occurring in a hospital in Cuernavaca, Mexico. MATERIALS AND METHODSPatients and bacterial strains. The General Hospital in the state of Morelos is a secondary-care facility with 100 beds. The neonatal intensive care unit has 8 beds. An outbreak was suspected in the neonatal intensive care unit due to an increased number of isolates of K. pneumoniae from blood cultures during a 4-month period. A retrospective epidemiological investigation included 74 children less than 2 months old hospitalized from June to October 1996.Twenty-one clinical isolates were from blood; another 10 duplicate strains were from sites other than blood (urine and catheter tip) corresponding to 10 patients. In total there were 31 clinical isolates identified as K. pneumoniae by the API 20E system (BioMerieux, Merck).Susceptibility testing. The antimicrobial susceptibility was initially determined with the MicroScan (Dade) system, using the Combo 14 panel. Subsequently, MICs of several ␤-lactams were determine...

The inappropriate use of antibiotics signifies a risk for individual health and a waste of health resources. It triggers the development of antibiotic resistance, which increases expenditures and mortality related to infectious disease, and is hence considered a serious public health problem. The World Health Organization has thus recommended a series of strategies to be included within national pharmaceutical policies. In Mexico, diverse factors related to the inappropriate use of antibiotics have been documented. While the response has been mainly in the form of educational and managerial interventions directed toward physicians in public health services, as well as epidemiological surveillance, there is a paucity of research and interventions focused on consumers, pharmacies, and the private sector. Fundamentally, a comprehensive national strategy for antibiotics is not incorporated into health and pharmaceutical policies.

The impact of invasive pneumococcal invasive disease is increased by the emergence of antibiotic resistance. We report regional and temporal variations in antibiotic resistance for 4,105 invasive Streptococcus pneumoniae isolates collected from Latin American children <5 years, between 1993 and 1999. Reduced susceptibility to penicillin was detected in 1,182 isolates (28.8%); 36% of these were resistant (> or = 2 microg/ml), including 12.6% with MIC > or = 4 microg/ml, occurring primarily in serotypes 14 and 23F. Reduced susceptibility to third-generation cephalosporins was detected in 12.1% of the collection. Mexico had the highest proportion of reduced susceptibility to penicillin (51.6%) and to third-generation cephalosporins (22%), whereas Brazil had the lowest at 20.9% and 0.7%, respectively. Isolates cultured from patients with pneumonia were more likely to have reduced susceptibility to third-generation cephalosporins than isolates from patients with meningitis (p < 0.0001). Susceptibility to trimethoprim-sulfamethoxazole, chloramphenicol, erythromycin, and vancomycin was tested by disk diffusion for 2.899 isolates. Reduced susceptibility was observed for 45.6%, 11.5%, 6.9%, and 0%, respectively. Thirty-one percent of the strains were resistant to > or = 2 drugs. High levels of antibiotic resistance in Latin America emphasize the need for the development of and adherence to rational antibiotic use guidelines. On-going surveillance will monitor the impact of these programs.

Community-acquired pneumonia is one of the leading causes of infant morbidity and mortality. Studies conducted in developing countries indicate that the most serious symptoms of pneumonia are associated with bacterial causes, mainly Streptococcus pneumoniae, followed by Haemophilus influenzae type b. Managing those infections in children under two years of age is hindered by the lack of appropriate vaccines and by the decreased susceptibility of S. pneumoniae to penicillin and other antibiotics. In 1993, at the initiative of the Regional System for Vaccines of the Pan American Health Organization, and with funding from the Canadian International Development Agency, a study was designed to identify the S. pneumoniae capsular types that cause invasive disease in Latin American children under 5 years of age. The objective of the study was to determine the ideal composition of a conjugate vaccine that could be used in Latin America, and the penicillin susceptibility of the S. pneumoniae isolates. The initiative was undertaken in Argentina, Brazil, Chile, Colombia, Mexico, and Uruguay. This report analyzes the information that the participating countries generated on pneumococcal pneumonia. A total of 3,393 children were found with systemic S. pneumoniae infections, of which 1,578 corresponded to pneumonias. The analysis focused on 1,409 cases of pneumonia in Argentina, Brazil, Colombia, Mexico, and Uruguay. Of the children, 63.8% of them were under two years of age. Twelve prevalent capsular types were identified, of which serotypes 14, 5, and 1 were the three most common in the majority of the countries. At the beginning of the study the highest level of penicillin resistance was found in Mexico (47.0%), and the lowest in Colombia (12.1%). Over the 1993-1998 period, resistance to penicillin increased in the five countries. Penicillin resistance was associated with a small number of capsular serotypes, mainly 14 and 23F. The first of those serotypes was resistant to penicillin and to trimethoprim-sulfamethoxazole, and the second was multiresistant. The frequency of resistance to trimethoprim-sulfamethoxazole was high in all of the countries; Argentina had the highest level, 58.0%. A decrease in susceptibility to chloramphenicol was uncommon, except in Colombia, where there was a resistance level of 23.4%. Resistance to erythromycin was low in all the countries, and all the isolates were susceptible to vancomycin.