Comparison of risk factors for Methicillin Resistant Staphylococcus aureus (MRSA) colonization in healthy newborns, born to mothers with and without MRSA colonization

Objective: To compare the risk factors for MRSA colonization in healthy newborns, born of mothers with and without MRSA colonization.

Methods: This case control study was conducted in post-natal unit of Lady Willingdon Hospital, affiliated with King Edward Medical University/Mayo Hospital, Lahore from January to June 2017. The vaginal and anterior nares swabs for MRSA culture were collected from mothers within six hours before planned delivery and the neonatal anterior nares swabs for MRSA culture were taken within one hour of birth. All the samples were cultured in Paediatric Microbiology laboratory in Mayo Hospital. Data were analyzed through SPSS 20.0 and logistic regression was applied for risk factors analysis.

Results: Out of total 80 mothers and their newborns, 15 (18.75%) mothers and 16 neonates (20%) were MRSA colonized. The frequency of MRSA colonization in mothers' anterior nares and vaginal swab was 17.5% and 1.25% respectively. The significant risk factors were prolonged rupture of membranes for >18 hours (p-value 0.02, odds ratio 11.85, 95% CI 1.41-99.3), birth weight <2500 grams (p-value 0.01, odds ratio 5.39, 95% CI 1.35-21.4), history of presence of meconium (p-value 0.006, odds ratio 7.30, 95% CI 1.78-29.8). The non-significant factors were age of mother (p-value 0.682, odds ratio 0.765, 95% CI 1.0.212-2.76), parity (p-value 0.185, odds ratio 3.82, 95% CI 0.46-31.66) , gestation (p-value 0.615, odds ratio 0.797, 95% CI 0.714-0.89) , mode of delivery (p-value 0.576, odds ratio 0.543, 95% CI 0.062-4.76), sex of baby (p-value 0.546, odds ratio 0.683, 95% CI 0.196-2.37) and presentation of baby at birth (p-value 0.47, odds ratio 0.795, 95% CI 0.71-0.89).

Conclusion: The presence of meconium, prolonged rupture of membranes and low birth weight were the significant risk factors for MRSA colonization in healthy new-borns, born to mothers with and without MRSA colonization.