Our study revealed that the prevalence of MRSA was 56.3%, which is greater than that reported by Idris et al19 (27.2%), Sa’adu et al20 (37%) and Uwe et al21 (47%) but far less than that reported by Obadare et al. (87%)22. The numbers are notably high and concerning, particularly as there appears to be a shift in the organisms associated with NS from predominantly Enterobacteriaceae to Staphylococcus aureus.21,23 We have observed a similar pattern in our centre. Initially, Staphylococcus aureus24 was the predominant organism, which transitioned to Escherichia coli25 over a decade later. Now, we have observed a return to Staphylococcus aureus as the predominant organism. Interestingly, these S. aureus isolates are now increasingly methicillin resistant19,20,21,22, and we wondered what could be the reason(s) for this observation: A change in the organisms colonizing the maternal genital tract or the environment, increasing antimicrobial resistance, climate change or a combination of any of these factors? However, this issue needs to be investigated. We also found MRSA infection in our study to be sporadic, presenting as either EOS or LOS and therefore likely community acquired. This observation was similarly reported by others19,20,21,22 and in contrast to reports in developed countries where MRSA infection in neonates was mostly a result of outbreaks in NICUs and therefore was hospital-associated.7 Despite the lack of extensive data on the actual prevalence of neonatal MRSA colonization and infection in developing countries, including Nigeria, the increasing number of neonatal MRSA cases presenting at hospitals, as we have pointed out, suggests a potentially high burden of colonization or infection within the community. It may be safe to infer that, while MRSA infection in neonates in developed countries is likely a result of advances in neonatal care, in developing countries, it is a problem of poverty with its attendant consequences. In our study, we discovered that early-onset MRSA (EOS) infection occurred in 33.7% of patients. This is likely attributed to acquisition through the maternal genital tract as the baby traverses the birth canal during delivery. This assumption is supported by previous studies in Nigeria, which reported high MRSA carriage rates in urine samples from healthy women and high rates of MRSA detection in vaginal swabs of pregnant women, reaching up to 37%.26,27 Additionally, there is a possibility of contamination of delivery items with MRSA from the environment, especially in home deliveries. We found that almost all of the deliveries occurred outside the hospital, and usually, home deliveries attended by either a relative or a traditional birth attendant are the norm in our environment. We believe that the potential source of early colonization and subsequent infection may be linked to either the maternal birth canal or the hands of the birth attendant. The following question arises: which is a safer option in terms of minimizing the risk of transmission? Conversely, we suspect that the source of LOS MRSA infection could be through breastfeeding, as reported by Schaumburg et al.13 Additionally, contact with the mother and other individuals may play a role, especially considering our cultural practices where newborns are often passed around to well-wishers in the first few days of life, potentially increasing the risk of exposure to MRSA. Moreover, the lack of data on MRSA colonization in the general population in our country, coupled with poor environmental sanitation, further complicates the situation. The clinical features of MRSA include nonspecific features at one end and invasive disease leading to death at the other end. We found nonspecific features similar to those reported by Vergnano et al. 14 and in contrast to those reported by other authors.16,28,29 We speculated that this difference arose from the level of maturity and immune system development, type of MRSA strain, source of infection, initial infection dose and time of hospital admission. Community-acquired MRSA is known to be more sensitive to antibiotics than hospital-acquired MRSA.7 The antibiotics with the most sensitivity in this study were ciprofloxacin and chloramphenicol, and at best, this can be considered fair. A similar finding was reported by Medugu et al23, in contrast to reports by Uwe et al19 and Obadare et al22, who reported poor sensitivity to levofloxacin and ciprofloxacin, respectively. Again, there is an increasing trend in antimicrobial resistance, and there are virtually no data on the genotype of the MRSA strain causing neonatal infection and what role it plays in antimicrobial resistance in Nigeria. We speculated several plausible reasons for the observed trend, including the emergence of HA-MRSA strains in the community and the loss of phenotypic and genotypic distinctions between HA-MRSA and CA-MRSA, as reported in the literature.7 Additionally, we considered the possibility of new mutations giving rise to hybrid or novel strains, particularly since strains with untypeable genotypes have been reported in adults in our country in previous years.30 We also believe that the indiscriminate and rampant use of antibiotics in our environment is widespread, and this is a result of easy access to most, if not all, antibiotics over the counter for both humans and animals. Fake and substandard drugs and a lack of antibiotic stewardship even in formal settings may contribute.
Our unit policy for the treatment of neonatal sepsis is ampicillin-cloxacillin and gentamicin, which are also used in the WHO and national guidelines, and ciprofloxacin is used as a 2nd-line drug. Our findings revealed that while ciprofloxacin and chloramphenicol have the highest sensitivity, ciprofloxacin is inexpensive and readily available and has fewer side effects than chloramphenicol; therefore, it may be a better option as a first-line drug. Ciprofloxacin is one of the second-line drugs used to treat multidrug-resistant (MDR) tuberculosis (TB). An antibiotic of first choice for the treatment of NS could impact the future treatment of MDR TB, especially considering the high burden of TB in our environment. This is exacerbated by issues such as poor antibiotic stewardship, the adaptability of the causative organism with genetic flexibility, and the likely escalation of resistance to antimicrobials, including fluoroquinolones17. Conversely, it offers the advantages of reduced hospital stays, reduced costs of care and improved short- and long-term clinical outcomes. This scenario highlights the delicate balance between addressing immediate healthcare needs and safeguarding the efficacy of antibiotics for future challenges. Vancomycin sensitivity was not assessed in our study. As the antibiotic of last resort, it could serve as a hope for the treatment of MRSA infection in the future if the current trend persists unabated. The unavailability and high cost of vancomycin in our environment might serve as a barrier against the development of resistance to the organism, thereby providing a vital treatment option in cases where other antibiotics fail. However, this unaffordability may again hinder its use in our environment, as most of the population lives under extreme poverty.
The prognosis in our study was excellent; however, the hospital stay was extended. We suspect that the reported increase in virulence of CA-MRSA leads to a more pronounced inflammatory response. Additionally, the choice of the first-line antibiotic may be another factor, particularly since the traditional method of organism isolation, which is cumbersome and takes an average of 5–6 days, was employed. This may have likely increased the overall cost of care and long-term morbidity.