Here we report an outbreak of Klebsiella pneumoniae infections harboring extended spectrum β-lactamases (ESBL) and armA 16Sr RNA methylase that were detected in pediatric and neonatal intensive care units during the 2010 and 2011 surveys of 100 clinical strains of K. pneumoniae from Annaba hospitals in Algeria. Antibiotic susceptibility testing was performed using the disk diffusion method. Minimum inhibitory concentrations of three classes of antibiotics were determined using the E. test. Standard polymerase chain reaction amplification and sequencing were performed using primers targeting ESBL, 16S ribosomal RNA (rRNA) methyltransferases, aminoglycoside-modifying enzymes (AMEs), and quinolone encoding genes. Clonal relationships among the clinical isolates were performed using multilocus sequence typing. From our clinical isolates, we found high rates of antimicrobial resistance that were linked to the presence of different ESBL encoding genes and AMEs, including 23 strains that harbored several ESBL encoding genes along with the 16S rRNA methyltransferase armA. Among these isolates, we identified a cluster of eight isolates of the ST39 clone between February and June 2010 in a pediatric ward, suggesting that an outbreak had occurred during this period. In conclusion, the emergence of multidrug-resistant clones, which were likely responsible for a nosocomial outbreak, is worrying because there are already limited options in those critical situations. Finally, we believe that surveillance should be implemented to monitor the risk of emergence and spread of carbapenemases in Algeria.