Background: the resistance of enterobacteriaceae to antibiotics is experiencing a worrying worldwide development with an increasing impact of β-lactamases. Klebsiella pneumoniae is one of the bacteria responsible for nosocomial infections. Hence the need to look for these enzymes in the hospitals of the Littoral region, Cameroon. Method: cross-sectional and descriptive study during 2016 and early 2017, isolates of intermediate sensitivity or resistant to third generation cephalosporins (C3G) collected in the laboratories of the Littoral referral hospitals and in Diagmed laboratory. Confirmation of the strains made by the API 20E™ gallery, the study of antibiotic sensitivity by the method of diffusion of discs on agar (Mueller Hinton). The double synergy test for the search of extended spectrum β-lactamases (ESBL), and confirmation by the Eurobio ™ kit (France). Results: a total of 412 strains of klebsiellasp (species) were isolated and 122 Klebsiella pneumoniae included. The majority age group is that ≤1 year with 26.0%, the germs were isolated in the urine at 54.6% and in neonatology and pediatrics at 35.8%. Klebsiella pneumoniae pneumoniae identified at 82.4%. The production of BLSE was 86.9%, against that of AmpC at 3.30%. The sensitivity to imipenem and amikacin was 96.2% and 98.1%, respectively. Conclusion: the study shows a high frequency of ESBL and a low presence of ampC in the Littoral region, Cameroon; practitioners must make a rational prescription from a correctly performed antibiogram.