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Journal of Drug Delivery and Therapeutics
Open Access to Pharmaceutical and Medical Research
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Open Access Full Text Article Research Article
Prevalence of Staphylococcus aureus and Enterococcus sp. Among Pregnant Women Attending General Hospitals in Delta Central Senatorial District, Nigeria
Egbule Olivia Sochi 1, Morka Emmanuel 1*, Omenogor Patricia Konye 2
1 Department of Microbiology, Delta State University, Abraka, Nigeria
3 Department of Nursing Science, Delta State University, Abraka, Nigeria
Article Info: _________________________________________________ Article History: Received 03 Jan 2024 Reviewed 08 Feb 2024 Accepted 26 Feb 2024 Published 15 March 2024 _________________________________________________ Cite this article as: Egbule OS, Morka E, Omenogor PK, Prevalence of Staphylococcus aureus and Enterococcus sp. Among Pregnant Women Attending General Hospitals in Delta Central Senatorial District, Nigeria, Journal of Drug Delivery and Therapeutics. 2024; 14(3):22-26 DOI: http://dx.doi.org/10.22270/jddt.v14i3.6441 _________________________________________________ *Address for Correspondence: Morka Emmanuel, Department of Microbiology, Delta State University, Abraka, Nigeria
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Abstract ____________________________________________________________________________________________________________ This study aimed to assess the prevalence of Staphylococcus aureus and Enterococcus sp. among pregnant women who visit the General Hospital in Delta Central Senatorial District, Nigeria. Samples were collected from the vaginal and rectum areas of pregnant women attending the General Hospitals of Abraka, Oghara, Udu, Ughelli North and Ughelli South. Bacteriological and biochemical analyses were conducted to isolate, characterize, and identify the bacteria. Two types of bacteria were found; Enterococcus sp. and Staphylococcus sp. The study result showed that Staphylococcus aureus (13.7%) was more prevalent than other isolates and was found in samples obtained from Udu General Hospital. In comparison, Ughelli South General Hospital had the lowest prevalence for S. aureus (7.9%). Samples from Oghara General Hospital had the highest prevalence for Enterococcus sp. (3.7%) while the lowest prevalence for Enterococcus sp. (1.1%) was obtained from Ughelli South General Hospital. S. aureus (51.6%) was found to be the most prevalent bacterium, while Enterococcus sp. (11.1%) was the least prevalent. The bacterial load from the vaginal swab samples was higher than that of rectum swab samples, which suggests that pregnant women attending these hospitals may have infections. The total bacterial count among pregnant women was highest in samples obtained from Udu General Hospital (5.4±0.5), followed by Abraka (5.0±0.6), Oghara (4.8±0.2), and Ughelli North (4.5±0.15), and while the least count was recorded from samples obtained from Ughelli South General Hospital (3.0±0.2). This study helps manage and plan future medical treatments. Pregnant women should be screened early in their pregnancies, between the 12th and 16th weeks, which is the second trimester, and treated appropriately to avoid complications that arise from untreated infections. Keywords: Prevalence, vaginal, pregnancy, women, infection |
INTRODUCTION
Although prenatal care has advanced and public awareness has increased, adverse pregnancy outcomes remain a significant public health concern globally. The vagina of humans is home to a diverse microbiota that has a protective function in maintaining good health. However, if this microbiota is disrupted, it can hurt the reproductive health of women, particularly during pregnancy. 1 During pregnancy, women are more likely to develop Urinary tract infections (UTIs) due to hormonal changes and a shift in the position of the urinary tract. This can make it easier for bacteria to reach the kidneys, leading to symptomatic and asymptomatic bacteriuria (bacteria in the urine). Asymptomatic bacteriuria can be particularly dangerous, as up to 45% of untreated cases can lead to pyelonephritis (inflammation of the kidney and pelvis), which can cause complications during pregnancy. If left untreated, a kidney infection can also result in serious conditions like acute respiratory distress syndrome (ARDS) or sepsis, which can be life-threatening.
The prevalence of bacteriuria in women has been reported to range between 3 to 20% in different studies. 2 If left untreated, UTIs during pregnancy can increase the risk of multiple maternal and neonatal complications. When gestational UTIs are accompanied by risk factors such as urolithiasis, recurrent UTI, urinary tract abnormalities, chronic inflammatory diseases, autoimmune disorders, renal parenchymal diseases, and diabetes mellitus, they become more complicated.3 Hence, it is crucial to treat gestational UTIs promptly. Furthermore, identifying the uro-pathogens in obstetric populations is important to optimize the empiric antibiotic treatments used for treatment.2
Several studies have been conducted on the microorganisms that are commonly observed in UTIs during pregnancy. Among these microorganisms, Escherichia coli is reported to be the most frequent and has been associated with multiple antimicrobial resistance in both clinical and environmental isolates in Nigeria.4,5,6,7,8,9. Other microorganisms, such as Klebsiella pneumonia, Enterococcus faecalis, Staphylococcus epidermidis, Streptococcus mitis, and Candida albicans are also frequently found in UTIs. 10
Over the last decade, Staphylococcus aureus has become a leading cause of infections in healthcare settings. S. aureus is the most common species of the Staphylococcus genus that causes staphylococcal infections in humans. These bacteria can cause community-acquired and nosocomial infections, as well as antibiotic-resistant infections such as methicillin-resistant S. aureus (MRSA). It is commonly found colonizing the throat, skin, and gastrointestinal tract of humans. S. aureus has many virulence factors, including toxins and proteins that allow it to cling to tissues and evade the immune system. The elderly, HIV-infected patients, transplant patients, and pregnant women are at higher risk of infection.
Although Enterococcus are Gram-positive cocci that normally inhabit the gastrointestinal tract of humans. They can cause illness in certain situations, their prevalence has increased significantly in hospitals over the past two decades, and this is due to antibiotic resistance. 11
Infections due to enterococci are a serious concern due to their ability to grow in extreme environments, as well as their intrinsic and frequent association with multidrug antibiotic resistance, making them a topic of interest. The focus of this paper is on enterococci and staphylococcus, two important pathogens during pregnancy. Limited data exists on the prevalence rates of S. aureus and Enterococci among pregnant women who attend General Hospitals in the Ethiope East Local Government Area of Delta State. Therefore, it is urgently necessary to obtain more information about the prevalence of S. aureus carriage and Enterococcus infection in this population.
MATERIALS AND METHODS
Figure 1. Map of the Study Area (Source: Niger Delta Atlas)
This research was conducted on pregnant women who visited General Hospitals in Delta Central Senatorial District, specifically in the towns of Abraka, Oghara, Udu, Ughelli South, and Ughelli North in Delta State. The main ethnic group of the study area is Urhobo, and Christianity is the predominant religion. The residents are engaged in various occupations, such as farming, fishing, trading, civil servants, entrepreneurs, and business.
The study collected One hundred and fifty (150) rectum and vaginal swabs from pregnant women who attended General Hospital Abraka, Eku, Udu, and Oghara teaching hospitals and agreed to participate. The swab sticks were then transported in Amies transport media to the Microbiology Laboratory located in Site II of the Delta State University in Abraka.
A ten-fold serial dilution of the sample was performed, which was then inoculated on general-purpose media (Nutrient Agar), Blood Agar, and MacConkey Agar. The inoculated plates were incubated at 37°C for 24 hours. After incubation, distinct colonies were picked for sub-culturing and stock culture, which were then cultured on selective and differential media to aid in the isolation and identification of the organisms. Additionally, Gram staining techniques and several biochemical tests were conducted to confirm the identity of the isolated organisms.
RESULTS
The biochemical characteristics and cultural morphology of the bacteria isolated from pregnant women in the study region which included: Staphylococcus aureus and Enterococcus sp. are listed in Table 1. Table 2 displays the total count of bacteria in the pregnant women's sample obtained from the 3rd dilution factor (x103). The highest count was obtained from UDU LGA (5.4±0.5), followed by Abraka (5.0 ± 0.6), while the lowest count was observed from Ugheli South (3.0± 0.2). The prevalence of different bacteria isolated from pregnant women in the study region is shown in Table 3. The prevalence of Staphylococcus aureus 98 (51.6%) was higher than Enterococcus 21 (11.1%). Figure 2 demonstrates the prevalence of these bacterial isolates.
Table 1: Biochemical Characteristics and Cultural Morphology of the Bacteria Isolates
|
|
|
|
|
|
|
|
|
Cocci |
+ - - |
- - - |
- |
+ |
+ + |
|
- |
- Enterococcus sp. |
Cocci + + - |
+ - + |
- |
+ |
+ + |
+ |
- |
- Staphylococcus aureus |
Key: + = positive, - = negative, v=variable
Table 2. Total Bacteria count of the Sample among pregnant women (x103)
Sampling Site |
Bacteria Count |
Abraka |
5.0 ± 0.6 |
Oghara |
4.8 ± 0.2 |
Udu |
5.4±0.5 |
Ughelli South |
3.0± 0.2 |
Ughelli North |
4.5±0.15 |
Values are expressed as mean ± Standard deviation
Table 3: Prevalence of bacterial isolates
No. of isolates according to source in % Prevalence
Staphylococcus aureus 10.5 10.5 13.7 8.9 7.9 51.6
Enterococcus sp. 2.6 3.7 2.1 1.6 1.1 11.1
Figure 2: Percentage prevalence of the Bacterial Isolated from Pregnant women
DISCUSSION
Despite the progress in prenatal care and growing awareness among the public, adverse pregnancy outcomes continue to pose a significant public health issue globally. The human vagina is home to a diverse microbiota that plays a protective role in maintaining good health. However, when this microbiota is disrupted, it can have negative consequences on women's reproductive health, particularly during pregnancy.12 There are various studies related to the most frequently observed microorganisms in UTIs during pregnancy. Escherichia coli is reported to be the most critical microorganism which should be kept in mind.13 Other bacterial species that have caused colonization in pregnant women reported from other studies include: Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa, Staphylococcal species, Enterococcus sp. and Group B streptococci.
In this study, however, the prevalence of Staphylococcus aureus and Enterococcus sp was determined for pregnant women who attend the General Hospital Abraka, Eku, Udu, and Oghara Teaching Hospital, Delta State, Nigeria. And the bacterial isolates identified were Enterococcus sp. and Staphylococcus aureus presented in Table 1. These bacteria isolated are in line with that of other similar studies of. 2, 14, 15,
Evaluation of the bacteria count of the samples obtained from the pregnant women using the 3rd dilution factor indicated mean ± SD of 50 ± 2.3, 48 ± 4.2, 54±0.5, 30± 1.8, and 45±0.4 for Abraka, Oghara, Udu, Ughelli South and Ughelli North General Hospitals respectively as presented (Table 2).
From the study, the prevalence of Staphylococcus aureus was 10.5%, 10.5%, 13.7%, 8.9%, and 7.9% for General Hospital Abraka, Teaching Hospital Oghara, and General Hospital in Udu, Ughelli North and Ughelli South respectively (Table 3). S. aureus had an overall prevalence of 98(51.6%). Staphylococcus aureus was the dominant pathogen isolated in this study and this is in agreement with previous studies of .14 conducted in UBTH in Benin and. 16 which had similar findings. However. 17 reported a lower prevalence of 6.9% in pregnant women and 7.7% in non-pregnant women in their study which they attributed to the higher socioeconomic and educational status of those assessing antenatal services at the UPTH which is a tertiary hospital as well as the stringent measures applied in conducting the laboratory tests.
The rate of vaginal carriage of S. aureus has been reported to be 4% – 22% of the vaginal microbiota of pregnant women .15 The risk factors for S. aureus colonization in pregnancy and the association between maternal colonization and infant infections are not very well defined.
Staphylococcus aureus and non-aureus coagulase-negative staphylococci possess a remarkable ability to acquire resistance to multiple antibiotics and the obvious clinical implication of this is limited therapeutic options with attendant increase in mortality and morbidity. 18 The options for chemotherapy are further narrowed in pregnancy when some effective drugs may be contraindicated and this makes the high prevalence of Staphylococcus aureus observed in this study all the more worrisome and the need to find solutions more imperative. 19
In addition, the assessment of the prevalence of Enterococcus sp. from this study was 5(2.6%),
7(3.75), 4(2.1%), 3(1.6%) and 2(1.1%) for General Hospital Abraka, Teaching Hospital Oghara, General Hospital in Udu, Ughelli North and Ughelli South respectively (Table 4.3). The overall prevalence of Enterococcus sp. in the study area was 21(11.1%). This report agrees with that of 20 who observed a prevalence of (12.9%) for Enterococcus faecalis. Other studies have also reported Enterococcus sp. as the most frequent gram-positive organism detected and had been noted as a significant bacterial isolate from women with UTI during pregnancy. 21
Enterococcus sp. is part of the normal flora of the genital tract however, it can be implicated and cause urinary tract infections and opportunistic infections which result in subacute bacterial endocarditis and abdominal abscesses. 22 The predominance of asymptomatic genital tract infection in pregnant women has been reported in several literature, with enterococci causing life-threatening infections in preterm infants and other immunocompromised patients. Maternal Enterococci bacteremia may lead to shock or disseminated intravascular coagulation. 23
The enterococcal species which are considered to be significant pathogens for humans are E. faecalis and E. faecium. These organisms are likely to affect patients who are elderly or whose normal microbiota has been altered by antibiotic treatment. 24 Furthermore, in neonates, E. faecalis is associated with a 6% mortality rate in early-onset septicaemia (EOS) which increases to 15% in late-onset (LOS) infections, whilst in general it is implicated in 7% to 50% of fatal cases. 25 E. faecalis is considered to increase tst expression leading to increased production of toxic shock syndrome toxin-1 thus increasing the virulence of S. aureus. Enterococci are believed to be difficult to treat because of their intrinsic resistance to antibiotics including beta–lactams and aminoglycosides which are frequently used to treat infections due to Gram-positive cocci. Resistance to trimethoprim, gentamycin and vancomycin have also been reported by. 26
The presence of E. faecalis in the amniotic fluid considerably increases the risk of histological inflammation of the placenta and also increases the risk for bronchopulmonary dysplasia (and necrotizing enterocolitis. 27
According to the National Healthcare Safety Network and Centers for Disease Control and Prevention, S. aureus and Enterococcus sp. are the two most commonly reported pathogens, accounting for 15.6% and 13.9% of healthcare–associated infections, respectively. In particular, S. aureus is notorious for its ability to acquire resistance to any antibiotic during the treatment of infection-associated infertility. 28
CONCLUSION
This study revealed Staphylococcus aureus had a high prevalence among the pregnant women in the study area thus suggesting a possible infection. Though, Enterococcus sp. prevalence was quite moderate. However, knowing the pathogens associated with infections among pregnant women is beneficial in the management and better planning of future medical treatments. Maintaining a healthy vaginal status during pregnancy is vital to the control of opportunistic infection which may result in poor pregnancy outcomes. In addition, pregnant women should be screened early in their pregnancies, between the 12th and 16th weeks which is the second trimester of pregnancy.
Conflict of Interests: The authors declare no conflict of interest
Ethical Approval: No Ethical approval is required
Consent: Informed written consent was taken from patients
Funding: There is no funding to report
Authors Contribution: All authors contributed to the work
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