Microbiological profiles of Gram-negative bacteria isolated from respiratory samples of mechanically ventilated patients at a tertiary Moroccan hospital.

OBJECTIVES

To characterise the Gram-negative bacteria implicated in ventilator-associated pneumonia (VAP), focusing on their antimicrobial resistance profiles and phylogenetic relationships.

METHODS

Seventy-eight isolates were collected from protected distal samples over two years; patients were under mechanical ventilation in the three adult ICUs of a Moroccan tertiary hospital. Isolates were identified using VITEK2. PFGE and FTIR determined genetic relationships, whereas the detection of genetic resistance determinants was carried out using PCR.

RESULTS

Carbapenem-resistant Acinetobacter baumannii harbouring the bla-OXA-23 was the predominant Gram-negative bacterium. Klebsiella pneumoniae was the most prevalent among the Enterobacterales, with a high resistance rate to almost all antibiotics, due to the coexistence of (bla) CTX-M-1, TEM, SHV, and OXA-48-like genes. Escherichia coli exhibited high resistance to ciprofloxacin (86%), ceftazidime (86%), and cotrimoxazole (71%). Proteus mirabilis was highly resistant to cotrimoxazole (60%) and ticarcillin (80%). Pseudomonas aeruginosa was resistant to carbapenems in 39% of cases, in which bla NDM and bla VIM were the only metallo-beta-lactamase genes detected. In phylogenetic analysis, both FTIR and PFGE techniques underscored no epidemiological relationship among strains.

CONCLUSION

The prevalence of MDR and XDR bacteria among VAP cases in a tertiary hospital in Morocco is increasing, potentially due to the coexistence of antimicrobial resistance genes.