[Epidemiological profile of pertussis in infants in Casablanca from 2012 to 2019]. / Profil épidémiologique de la coqueluche du nourrisson à Casablanca de 2012 à 2019.

Pertussis is a real public health problem due to high neonatal morbidity rates and resurgence despite high vaccination coverage. The purpose of this study is to analyze the epidemiological profile of pertussis in infants hospitalized from 2012 to 2019. We conducted a retrospective, descriptive study over a 7-year and 8-month period from January 2012 to July 2019. It involved 500 infants admitted with clinical suspicion of pertussis. The average age of infants was 72 days, ranging from 28 days to 18 months; 75% of infants were less than 3 months old. The peak incidence was registered in 2012 and 2016, with a summer predominance (32%); 460 infants (92%) were not or incompletely vaccinated, 42.2% of whom were too young to be vaccinated. A probable contaminant in the entourage was found in 43,6% of cases. Whooping cough and cyanosis were the main reason for hospitalization (77.6%). Chest radiography objectified bronchial disease (25,4%) and alveolar foci (22.7%). Blood count performed in 410 infants showed hyperlymphocytosis in 67.5% of cases. Polymerase chain reaction (PCR) on nasopharyngeal sample collected from 206 infants was positive for Bordetella pertussis in 64% of cases; 118 PCR performed in mothers were positive in 47.7% of cases. All infants received Clarithromycin. Pertussis is a major cause of morbidity in infants in Casablanca. The prevention strategy is based on vaccination of family members of infants. However, vaccination of pregnant women appears to be more effective.

Behaviour of Listeria monocytogenes in raw sausages (merguez) in presence of a bacteriocin-producing lactococcal strain as a protective culture.

The effectiveness of a bacteriocin produced by Lactococcus lactis subsp. lactis M in reducing population level and growth of Listeria monocytogenes ATCC 7644 in fermented merguez sausage was examined. Two different formulas (with or without added nitrites) were assayed and predetermined numbers of Listeria (ca 10(6) cfu g(-1)) were added to sausage mixture. The effect of in situ production of the bacteriocin by Lactococcus lactis M on Listeria monocytogenes ATCC 7644 during fermentation and storage of merguez sausages at room (ca 22 °C) or at refrigeration (ca 7 °C) temperature was tested. Results indicated that counts of Listeria monocytogenes were decreased during fermentation of merguez samples fermented with either the bacteriocin-producing Lactococcus lactis M (Bac(+)) or a nonbacteriocin-producing Lactococcus lactis J (Bac(-)). However, reduction in Listeria cfu's was greater in samples fermented with the Bac(+) than in those fermented with the Bac(-) starter. In merguez sausage made without nitrites addition, the Bac(+) starter induced further decrease in Listeria counts by 1.5 log cycles compared with that induced by the Bac(-) starter. While in merguez samples with added nitrites (0.4%), the effect of the bacteriocin produced in situ was less important than in those made without nitrites addition.