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Staphylococcus aureus is an infrequent cause of community-associated (CA-SA) pneumonia in children. The aim of this study was to evaluate the clinical, epidemiological, microbiological, and molecular characteristics of CA-SA pneumonia among children hospitalized in two large tertiary care referral centers during an 8-year period. Cases of CA-SA pneumonia admitted between 2007 and 2014 were retrospectively examined through medical record review. Molecular investigation was performed for available strains; mecA, Panton-Valentine leukocidin (PVL) (lukS-lukF-PV), and fibronectin binding protein A (fnbA) genes were detected by polymerase chain reaction (PCR). Clones were assigned by agr groups, pulsed-field gel electrophoresis (PFGE), SCCmec, and multilocus sequencing typing (MLST). In total, 41 cases were recorded (boys, 61 %), with a median age of 4.3 months (range, 1-175). Methicillin-resistant S. aureus (MRSA) accounted for 31 cases (75.6 %). Complications included empyema (25/41, 61 %), pneumatoceles (7/41, 17 %), and lung abscess (1/41, 2.5 %). Intensive care unit (ICU) admission was required in 58.5 %. Two deaths occurred (4.9 %). Definitive therapy was based on vancomycin with or without other antibiotics (55.9 %), followed by clindamycin and linezolid (26.5 % each). All isolates were susceptible to vancomycin (MIC90 2 mg/L, range 1-2), teicoplanin, and linezolid, whereas 26.8 % were resistant to clindamycin. Among the 25 studied strains, 20 were mecA-positive (MRSA), carrying also the fnbA gene. Of these, 90 % belonged to the ST80-IV/agr3/PVL-positive clone. Methicillin-susceptible S. aureus (MSSA) strains showed polyclonality, 3/5 were PVL-positive, and 3/5 were fnbA-positive. MRSA and particularly the ST80-IV clone predominated among staphylococcal pneumonia cases in children. Treatment provided was effective in all but two patients, despite the relatively high minimum inhibitory concentration (MIC) of vancomycin and a high resistance to clindamycin.

Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infections in children have increased considerably in our area. In this study, we prospectively examined the epidemiological, clinical and molecular profile of CA-MRSA infections in children in central Greece. A total of 198 staphylococcal strains were isolated from patients with community-acquired infections over a 28-month period and 88 (44%) were found to be methicillin-resistant. Most patients with CA-MRSA had skin and soft-tissue infections (73%). Hospitalisation and surgery were more commonly required for patients with MRSA strains (p = 0.001 and p < 0.001, respectively). The presence of Panton-Valentine leukocidin (PVL) genes was identified in 28/41 (68%) CA-MRSA strains. All PVL(+) strains were found to carry a staphylococcal chromosomal cassette (SCC) mec element type IV and belonged to a single electrophoretic type similar to the European multi-locus sequence type 80 (ST80). The recent increase in CA-MRSA infections in children in our area is largely associated with the spread of the ST80 clone and their clinical characteristics are similar to those described in other parts of the world where different MRSA clones predominate.

The resistance pattern of 432 Streptococcus pneumoniae strains isolated from children with various infections over a 4-year period (1992-1995) was determined. The rates of resistance to penicillin, chloramphenicol, tetracycline, trimethoprim-sulfamethoxazole, erythromycin, clindamycin, cefotaxime, and vancomycin were 10%, 2.8%, 4.6%, 4.9%, 4.4%, 2.5%, 0.9%, and 0%, respectively. All strains not susceptible to penicillin were intermediately susceptible to penicillin-(MIC >0.06-< or = 1 microg/ml). Isolates not susceptible to penicillin were encountered significantly more often in children with localized infections than in those with invasive disease; these isolates displayed significantly lower susceptibility to non-beta-lactam agents as compared with their penicillin-susceptible counterparts.

The epidemiology of community-acquired Pseudomonas aeruginosa infections in children during a one-year period (January through December 1993) was evaluated. A total of 6,859 clinical samples, each one representing a separate individual with suspected infection, were cultured. Pseudomonas aeruginosa was isolated from 218 children with various infections occurring in the following order of frequency: chronic suppurative otitis media, 76.3%; appendicitis/peritonitis, 10.3%; osteomyelitis, 8.9%; skin or soft tissue infection, 6.3%; acute conjunctivitis, 3.0%; and urinary tract infection, 0.1%. A variety of O serogroups were identified: O1 (15.2%), O6 (14.7%), O11 (12.4%), O10 (11.5%), O3 (10.6%), O5 (5.1%), and O9 (4.6%). Other serogroups and nontypable strains were recovered at a frequency of 11.2% and 14.7%, respectively. Nontypable strains predominated in chronic otitis media (18.9%), while serogroups O1 (18.3%), O6 (17.5%), and O11 (17.5%) were recovered most frequently among the typable isolates. Susceptibility of Pseudomonas aeruginosa to antipseudomonadal agents was extremely high. The rate of susceptibility to ceftazidime was 99.6%, to azlocillin 98.6%, to piperacillin 98.2%, to aztreonam 97.3%, to gentamicin and netilmicin 97.7%, and to ciprofloxacin 99.1%. All isolates were susceptible to tobramycin, imipenem, and amikacin. The results might suggest that community-acquired Pseudomonas aeruginosa infections in children can be treated successfully with any antipseudomonadal antibiotic.