Objective: To determine the minimum inhibitory concentrations (MICs) of parenteral penicillin and moxifloxacin against Streptococcus pneumoniae strains isolated at a hospital center. Methods: In-vitro, prospective study involving 100 S. pneumoniae isolates collected from patients who had been treated, between October of 2008 and July of 2010, at the Hospital das Clínicas complex of the University of São Paulo School of Medicine, located in the city of São Paulo, Brazil. The isolates were obtained from respiratory tract cultures or blood samples unrelated to meningeal infections, and they were tested for penicillin and moxifloxacin susceptibility by E-test. The MIC category interpretations were based on updated standards. Results: All isolates were fully susceptible to parenteral penicillin (MIC ≤ 2 µg/mL), and, consequently, they were also susceptible to amoxicillin, ampicillin, third/fourth generation cephalosporins, and ertapenem. Of the S. pneumoniae strains, 99% were also susceptible to moxifloxacin, and only one strain showed an MIC = 1.5 µg/mL (intermediate). Conclusions: Our results showed high susceptibility rates to parenteral penicillin and moxifloxacin among S. pneumoniae isolates unrelated to meningitis, which differs from international reports. Reports on penicillin resistance should be based on updated breakpoints for non-meningitis isolates in order to guide the selection of an antimicrobial therapy and to improve the prediction of the clinical outcomes.

Keywords: Drug resistance; Penicillin G; Pneumococcal infections; Streptococcus pneumoniae; Respiratory tract infections. Drug resistance; Penicillin G; Pneumococcal infections; Streptococcus pneumoniae; Respiratory tract infections.

Streptococcus pneumoniae resistance to penicillin was studied in two hospitals in Caxias do Sul, Rio Grande do Sul, Brazil, between May 1998 and November 2001. From the 176 strains of invasive Streptococcus pneumoniae that were identified, 2.28% (CI 0.62-5.74) presented intermediate resistance, and 3.42% (CI 1.26-7.31) presented high-level resistance. Conclusion was that the use of penicillin in Caxias do Sul was still justified as treatment of pneumococcal pneumonia, differently from other centers where the penicillin was replaced by other antibiotics. These results confirm the statement of IDSA (Infectious Diseases Society of America) guideline for the management of community-acquired pneumonia in adults, that the choice of antimicrobial drug to treat pneumococcal pneumonia should be guided by local or regional prevalence of resistance to penicillin.

Background: Streptococcus pneumoniae is the most common etiologic agent of community-acquired respiratory infections. In recent years, S. pneumoniae resistance to antimicrobial agents has increased. Minimum inhibitory concentration (MIC) is routinely used to determine resistance. Polymerase chain reaction (PCR) detects the genes responsible for Streptococcus pneumoniae resistance to penicillin within approximately 8 hours. Objective: To compare the PCR and MIC methods in determining Streptococcus pneumoniae resistance to penicillin. Method: A total of 153 Streptococcus pneumoniae samples, isolated from various anatomical sites, were evaluated in order to detect mutations in the genes encoding pbp1a, pbp2a and pbp2x, which are responsible for Streptococcus pneumoniae penicillin resistance. A correlation was found between mutations and penicillin MIP, as determined by the agar diffusion method. Results: Overal Streptococcus pneumoniae resistance to penicillin was 22.8% (16.3% intermediate resistance and 6.5% high resistance). In a statistically significant finding, we observed no mutations in the penicillin-sensitive samples and only one mutation, typically in the gene encoding pbp2x, among the samples with intermediate resistance, whereas mutations in all three genes studied were observed in the high-resistance samples. Conclusion: For determining Streptococcus pneumoniae resistance to penicillin, PCR is a rapid method of detection that could well be used in clinical practice.

Keywords: Streptococcus pneumoniae. Penicillin resistance. Polymerase chain reaction/methods.

Objective: The aim of this study was to determine the prevalence of macrolide-resistant S. pneumoniae and to identify its phenotypic and genotypic characteristics. Methods: Strains of S. pneumoniae isolated in the city of Porto Alegre between May 2002 and August 2004 from samples collected from different anatomical sites were analyzed. For the agar diffusion test, disks of erythromycin, clarithromycin, azithromycin and clindamycin were used. The minimum inhibitory concentrations of erythromycin were determined for macrolide-resistant isolates by the agar dilution method. Macrolide-resistant isolates were phenotyped by agar diffusion test and genotyped by polymerase chain reaction. Results: A total of 229 pneumococcal strains were evaluated, 12 (5.2%) of which were macrolide-resistant. Among the 12 resistant strains, 9 (75%) presented the MLSB phenotype, and 3 (25%) presented the M phenotype. Polymerase chain reaction testing indicated that 8 MLSB phenotype isolates harbored the ermB gene only, whereas the mefE gene was present in all 3 M phenotype isolates. One MLSB phenotype isolate presented both genes. Conclusion: In Porto Alegre, the S. pneumoniae resistance to macrolides is still low since such resistance is due primarily to the presence of the ermB gene expressing the MLSB phenotype.

Objective: In the antibiotic era, purulent pericarditis is a rare entity. However, there are still reports of cases of the disease, which is associated with high mortality, and most such cases are attributed to delayed diagnosis. Approximately 40-50% of all cases of purulent pericarditis are caused by Gram-positive bacteria, Streptococcus pneumoniae in particular. Methods: We report four cases of pneumococcal pneumonia complicated by pericarditis, with different clinical features and levels of severity. Results: In three of the four cases, the main complication was cardiac tamponade. Microbiological screening (urinary antigen testing and pleural fluid culture) confirmed the diagnosis of severe pneumococcal pneumonia complicated by purulent pericarditis. Conclusions: In cases of pneumococcal pneumonia complicated by pericarditis, early diagnosis is of paramount importance to avoid severe hemodynamic compromise. The complications of acute pericarditis appear early in the clinical course of the infection. The most serious complications are cardiac tamponade and its consequences. Antibiotic therapy combined with pericardiocentesis drastically reduces the mortality associated with purulent pericarditis.

Keywords: Pneumonia, pneumococcal/complications; Pneumonia, pneumococcal/mortality; Pericarditis/therapy; Cardiac tamponade; Streptococcus pneumoniae/pathogenicity.

Objective: To determine the prevalence and the characteristics of Mycoplasma pneumoniae-related community-acquired pneumonia (CAP) and parapneumonic pleural effusion (PPE) in children and adolescents. Methods: This was a retrospective observational study involving 121 patients with CAP/PPE hospitalized in a tertiary referral hospital between 2000 and 2008, divided into six groups according to the etiologic agent (G1 to G6, respectively): M. pneumoniae with or without co-infection, in 44 patients (group 1); etiologic agents other than M. pneumoniae, in 77 (group 2); M. pneumoniae without co-infection, in 34 (group 3); Streptococcus pneumoniae, in 36 (group 4); Staphylococcus aureus, in 31 (group 5); and M. pneumoniae/S. pneumoniae co-infection, in 9 (group 6). Results: In comparison with group 2, group 1 showed higher frequencies of females, dry cough, and previous use of beta-lactam antibiotics; longer duration of symptoms prior to admission; and lower frequencies of use of mechanical ventilation and chest tube drainage. In comparison with groups 4 and 5, group 3 showed higher frequencies of previous use of beta-lactam antibiotics and dry cough; longer duration of symptoms prior to admission; a lower frequency of use of chest tube drainage; a higher mean age and a lower frequency of nausea/vomiting (versus group 4 only); and a lower frequency of use of mechanical ventilation (versus group 5 only). M. pneumoniae/S. pneumoniae co-infection increased the duration of symptoms prior to admission. Conclusions: In this sample, the prevalence of M. pneumoniae-related CAP/PPE was 12.75%. Although the disease was milder than that caused by other microorganisms, its course was longer. Our data suggest that M. pneumoniae-related CAP/PPE in children and adolescents should be more thoroughly investigated in Brazil.

Keywords: Pleural effusion; Empyema, pleural; Pneumonia; Mycoplasma pneumoniae.