感染症と治療ジャーナル

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Prevalence and Antibiotic Susceptibility of Staphylococcus Aureus and Other Staphylococcal Infections in Pregnant Women Attending Antenatal Clinic in a Tertiary Hospital in Port Harcourt, Nigeria

Stanley CN, Ugboma HAA, Ibezim EC and Attama AA

Background: Infections due to Staphylococcus aureus have been on the increase globally with serious implications for public health. Both adults and children can be affected. Although S. aureus commonly resides in the nose of apparently healthy humans, it can also colonize such other areas as the intestine, vagina, groin and armpit. It is known to cause asymptomatic and sometimes uncomplicated skin infections but has also been implicated in serious diseases such as endocarditis and toxic shock syndrome. Mounting evidence appears to support increasing Stapylococcus aureus colonization and infection among pregnant and postpartum women as well as neonates. Other members of the genus Staphylococcus have also been increasingly implicated as causative agents for a variety of disease conditions. In developing countries and resource poor settings, due to lack of adequate facilities or cost, staphylococcal isolates may not be definitively identified to the species and strain level. The result is that other members of the genus Staphylococcus may be erroneously identified as . Besides the obvious negative impact this practice may have on chemotherapeutic outcome and antibiotic resistance resulting from misuse of these drugs, the true prevalence of the various staphylococcal pathogens, especially Staphylococcus aureus, may not be known particularly with respect to pregnant women.

Objectives: We set out to determine the prevalence and antibiotic susceptibility of Staphylococcus aureus and other staphylococcal organisms in pregnant women and those of child bearing age at the University of Port Harcourt Teaching Hospital (UPTH) in Port Harcourt, Nigeria. We determined to identify every isolate to the species and strain level in order to establish their true prevalence and antibiotic susceptibility as well as any significant association between pregnancy status and rectovaginal colonization.

Method: We carried out a cross sectional prospective study involving 265 pregnant women attending antenatal clinic and 242 non-pregnant women attending the general outpatient clinic in the teaching hospital in Port Harcourt, Nigeria. High vaginal swab samples were aseptically collected from each participant and cultured using standard microbiological and biochemical methods. The isolated organisms were identified using the Biomieriux API staph® testing system and revealed a variety of staphylococcal species besides Staphylococcus aureus. Antibiotic susceptibility testing was done using the Bauer-Kirby disk diffusion method.

Results: Staphylococcus aureus was clearly the most common organism isolated with a prevalence of 6.9% and 7.7% in the pregnant and non-pregnant women respectively. The difference in the prevalence of Staphylococcus aureus in the pregnant and non-pregnant women was not statistically significant (p≤0.50). The antibiotic susceptibility testing results showed multiple drug resistance by the organisms isolated. A high level of resistance to the fluoroquinolones and cefixime a third generation oral cephalosporine was observed. Interestingly, a significant difference was seen in the susceptibility of isolates in the pregnant women to erythromycin when compared to those in the nonpregnant women (p≤0.50)

Conclusion: There is an increasing colonization and infection of the female reproductive tract by Staphylococcus aureus and other staphylococcal pathogens. Since these pathogens have been known to be transferable from infected mother to her infant either during or after birth and considering their virulence potential, there is need to take a closer look at the rate of rectovaginal colonization by these organisms in this population and their possible contribution to maternal and infant health.