The aqueous and ethanol extracts of four spices ( Monodora myristica, Piper guineense, Xylopia aethiopica, Tetrapleura tetraptera ) were prepared and the antibacterial properties assessed using the agar diffusion method. The test organisms were Enterohaemorrhagic E.coli, Shigella, Salmonella, Klebsiella, Pseudomonas, Klebsiella pnemonium, Staphylococcus aureus, Staphylococcus aureus (ATCC 25923), Bacillus sp. and Enterococcus faecalis. The susceptibility of the test bacteria strains to various antibiotics was performed. The aqueous extracts had antimicrobial activities on all test organisms used (MIC values of 30-60mg/ml and a range of inhibition, 10-25mm). The ethanol extracts were less sensitive (3.3-26mg/ml on E. feacalis). The phytochemical screening of the potent extracts revealed the presence of terpenoids, flavonoid and glycosides. The test organisms showed susceptibility to majority of the antibiotics used ranging from an average of 10mm-37mm. The aqueous extracts can be used as an alternative therapy to the use of antibiotics as the zones of inhibition exhibited by the test strains to both were comparable.

Cronobacter is a genus with emerging pathogens that has been associated with life threatening diseases in neonates, infants and immunocompromised adults. Three Cronobacter species were isolated from powdered infant formula retailed in Nigeria. Different methods of phenotypic and genotypic characterization were carried out. All the isolates were identified biochemically by Microscan identification analysis as Enterobacter sakazakii (98.87%). The Vitek MALDI-TOF system identified the isolates as Cronobacter sakazakii. 16S rRNA sequencing identified the isolates as C. sakazakii. In contrast the use of species-specific PCR assays targeting rpoB, and cgcA, helped to identify two of the three strains as C. sakazakii and the last strain was identified as C. malonaticus. Multi locus sequence typing (MLST) analysis was used to identify each strain's sequence type and the results identified three new sequence types: 303, 304 and 296. C. sakazakii BAA 894 served as a positive control for all the experiments. Biochemical methods and commercial identification systems are not sensitive enough to identify Cronobacter strains to the species level. Molecular methods are needed to confirm the species identity of strains.

Cronobacter spp. are emerging, opportunistic, food-borne pathogens associated with infections like meningitis, necrotizing enterocolitis and septicaemia in premature and immunocompromised neonates and infants. The phylogenetic relatedness of three Cronobacter species isolated from powdered infant formula retailed in Nigeria was carried out using a Pan-Genomic DNA Microarray constituting 19,287 independent genes representing 15 Cronobacter genomes and 18 plasmids and 2,371 virulence genes of phylogenetically related Gram-negative bacteria. The hybridization results showed that Cronobacter malonaticus (CS14) and Cronobacter sakazakii (CS17 and CS124) clustered with powdered infant formula environmental and clinical strains of C. malonaticus and C. sakazakii isolated from countries like Jordan, Czech Republic, Ireland and USA with a significant relatedness greater than 80%. The sequence types of C. malonaticus CS14 was ST303 and C. sakakakii CS17 and CS124 were ST304 and ST296, respectively. Some virulence genes (integrase of Shigella flexnerri bacteriophage X, hypothetical protein z1655, dihydrofolate reductase, and formate acetyltransferase 1) were detected in CS124 and CS17. Adequate regulatory measures should be applied to monitor imported and locally produced powdered infant formulae to prevent contamination with Cronobacter spp. and other food borne pathogens to ensure the safety of vulnerable neonates and infants.

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