This descriptive and exploratory observational case series examined intestinal colonisation and subsequent bacteraemia due to ESBL-producing Klebsiella pneumoniae (ESBL-Kp) in preterm neonates in Morocco. Prospective bacteriological cultures and antibiotic susceptibility testing were supported by phenotypic methods, including Brilliance ESBL Agar and the NG-Test CARBA-5 assay, for the rapid detection of ESBL and carbapenemase producers. Molecular analysis using PCR was also undertaken to identify specific resistance genes. A total of 567 rectal swabs were collected from 339 preterm neonates, yielding 293 K. pneumoniae isolates. ESBL-producing strains were identified in 53.6% of the neonates (182/339). Detected resistance genes included blaSHV (26.3%), blaCTX-M-1 (42.8%), blaTEM (30.2%), blaOXA-48 (50.0%), blaNDM(15.3%), and blaVIM (4.9%). Principal risk factors for colonisation were low birth weight (OR 1.69), very preterm birth (OR 6.24), enteral tube feeding (OR 2.02), and prolonged use of third-generation cephalosporins (OR 1.26). Among the neonates studied, 32 (9.4%) developed healthcare-associated bacteraemia, with 56.2% of these cases preceded by intestinal colonisation with ESBL-Kp. Clinically, severe respiratory distress and alveolar haemorrhage were strongly associated with increased mortality (aRR = 29.32 and 4.45, respectively). The findings highlight the clinical importance of early screening to guide infection control and antimicrobial stewardship in neonatal intensive care settings.

Background/Objectives: Peripheral intravenous catheters (PIVCs) are frequently used in neonatal intensive care units (NICUs) and can become major conduits of nosocomial infections, often colonized with clinically important bacteria, including methicillin-resistant Staphylococcus aureus (MRSA). Molecular data on PIVC-associated S. aureus in Moroccan NICUs remain limited. This study aimed to characterize bacterial colonization of PIVCs and investigate the phenotypic and molecular characteristics of recovered S. aureus, with particular emphasis on MRSA and staphylococcal cassette chromosome mec (SCCmec) types. Methods: 402 PIVC tips collected from 225 neonates hospitalized in the NICU of Hassan II University Hospital between June 2024 and May 2025 were analyzed using the Brun–Buisson quantitative culture method. Bacterial identification and antimicrobial susceptibility testing were performed, and S. aureus isolates were further characterized by PCR for 16S rRNA, mecA, and Panton–Valentine leukocidin (PVL) genes. SCCmec typing was performed on mecA-positive MRSA isolates. Results: Seventy-nine PIVC tips (19.7%, 95% CI: 16.1–23.8%) met the colonization criteria (≥1000 CFU/mL). A total of 152 bacterial isolates were recovered; S. aureus was the predominant species (n = 89, 58.6%), of which 15 (16.9%) were confirmed as MRSA. All MRSA isolates were mecA-positive. SCCmec typing identified two types; 12 isolates predominated and harboured SCCmec type IV (n = 12, 80.0%), while SCCmec type III was detected in three isolates (20.0%). No isolate harbored PVL genes, and no inducible clindamycin resistance was detected. MRSA isolates showed markedly higher resistance to gentamicin, fusidic acid, erythromycin, rifampicin, and clindamycin compared with MSSA isolates. Conclusions: S. aureus was the predominant bacterium recovered from PIVCs in our study. The predominance of SCCmec type IV among MRSA isolates provides original molecular epidemiological data from a Moroccan neonatal setting and highlights the need for continued surveillance of PIVC-associated MRSA and its molecular characteristics.

Staphylococcus aureus is a major human pathogen causing infections ranging from mild skin infections to life-threatening systemic conditions. Clindamycin has long been used to treat serious Staphylococcus aureus infections due to its pharmacokinetic profile and ability to inhibit toxin production. However, inducible resistance to clindamycin via erythromycin ribosomal methylases encoded by erm genes poses a significant clinical challenge; it often leads to treatment failure and remains undetected by routine antimicrobial susceptibility testing. This cross-sectional study analyzed 120 non-duplicate clinical Staphylococcus aureus isolates from the University Hospital Center of Fez, Morocco. Identification followed standard microbiological methods, and susceptibility testing adhered to the European Committee on Antimicrobial Susceptibility Testing (EUCAST/CA-SFM) 2024 guidelines. Inducible clindamycin resistance was assessed using the D-test, while methicillin resistance was determined by the cefoxitin disk diffusion method. Of the 120 isolates, 50 (41.67%) were resistant to erythromycin. Constitutive macrolide-lincosamide-streptogramin B (MLSB) resistance was detected in 31 isolates (25.83%), inducible MLSB (iMLSB) resistance in 5 isolates (4.17%), and the macrolide-streptogramin B (MS) phenotype in 14 isolates (11.66%). All isolates with inducible clindamycin resistance or the MS phenotype were methicillin-susceptible Staphylococcus aureus (MSSA), while constitutive MLSB resistance was more frequent among methicillin-resistant Staphylococcus aureus (MRSA). Inducible clindamycin resistance, though less prevalent, remains clinically significant and can be readily detected using the D-test. Routine use of the D-test is essential to guide appropriate antimicrobial therapy and prevent clindamycin treatment failure.