Neonatal sepsis caused by Streptococcus pseudoporcinus

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ESPR149
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Abstract: :

Neonatal sepsis is one of the leading causes of death in newborns. In 2006, Streptococcus pseudoporcinus, a facultative, nonmotile, Gram-positive coccus, was reported as a novel species that could be isolated from the female genitourinary tract and separated from Streptococcus porcinus . This novel species was found to be biochemically similar to GBS, with both producing large colonies (typically >0.5 mm) after 24 hours of incubation, causing difficulty in correctly identifying the species . To date there is very little information regarding the implications of colonization with this organism in terms of neonatal risks. 

            We describe a case of a male infant born at 27 weeks, who deteriorated rapidly and expired within 3 hours of life. Blood cultures grew Streptococcus  pseudoporcinus. To the knowledge of the authors, there have been no case reports describing Streptococcus pseudoporcinus sepsis leading to neonatal mortality. 

Case Report: Male neonate was born to a Caucasian 22 year old, gravida 2 para 0 0 1 0, mother. The pregnancy was complicated by preterm premature rupture of membranes (PPROM), which occurred at 18 weeks gestation, leading to oligohydramnios. Mother presented to delivery room at 27 weeks and 5 days gestation with contractions, fever of 100.4°F, cervical dilation to 3cm, and fetal tachycardia at 180 beats per minute. Baby was delivered by emergency Caesarean section. Mother received a dose of betamethasone, magnesium sulfate and  Ancef.  Maternal labs prior to Cesarean section showed leukocyte count of 14.6 .

Baby was delivered in breech position with clear amniotic fluid. He was cyanotic and hypotonic at birth with no respiratory efforts and was noted to have facial dysmorphism which included cleft lip and palate along with limb abnormalities. Baby did not respond well to positive pressure ventilation with bag and mask and was intubated with 2.5 mm endotracheal tube and given 100% oxygen with IPPV with improvement in heart rate and O2 saturation. APGAR scores at one, five, and ten minutes were 1, 5, and 6 respectively. 

 Baby weighed 1106 grams with a head circumference of 25 cm and length of 37.5 cm (all centile between 50th and 90th ). The neonate had features of amniotic band sequence which included  right hand malformation with amputation of fingers, left hand amputation of second, third and fourth digits, right leg amputation above the ankle, 2 x 3 cm area of absent skin over lower medial left leg, and left leg and toe malformation along with undescended testes and complete cleft palate. Baby was placed on SIMV, started on Ampicillin and Gentamicin along with IV fluids. Baby had severe respiratory distress and showed marginal improvement in spite of Surfactant therapy and increasing ventilator settings.  

Neonatal labs on admission to the NICU showed a leukocyte count of 14,000 with 7% bands and 14% Neutrophils. Arterial blood gas was indicative of severe mixed acidosis. Chest x-ray showed bilateral consolidation with air bronchograms. Baby had poor chest expansion and progressive decrease in saturation despite increased ventilatory pressures.

The neonate deteriorated rapidly. Parents were counseled about futility of continuing care in view suspected pulmonary hypoplasia and baby passed away in mother's arm at 3 hours of age. 

Subsequently, the peripheral blood culture  resulted in growth of aerobic gram positive cocci in chains, later identified to be Streptococcus pseudoporcinus. Placenta and cord were showed marked acute chorioamnionitis and acute vasculitis of the umbilical vessels. Fetal autopsy was declined and chromosomal analysis showed 46 XY. 

Discussion

            Streptococcus pseudoporcinus is a novel species, previously classified as Streptococcus porcinus, isolated from the female genitourinary tract that was first reported in 2006 . A study done in 2011 isolated S. pseudoporcinus in 5.6% of females tested, with independent risk factors for colonization being African American race, ages 30-40, recent Trichomonas vaginalis infection, having bacterial vaginosis, primary or recurrent genital herpes, and having two or more male sexual partners . Biochemically, it has been found to be similar to GBS and has been reported to cross react with commonly used serotyping kits for GBS, although recent advances in microbiological techniques have made it easier to detect this organism . S. pseudoporcinus has also been found to be phenotypically similar to S. agalactiae when cultured aside from exhibiting a wider zone of beta-hemolysis making it possible that cases of S. pseudoporcinus have been mistakenly diagnosed as S. agalactiae . A study in 2019 by Grundy et al., however, found a strong correlation with colonization with Streptococcus pseudoporcinus and premature preterm rupture of membranes (PPROM) as well as spontaneous preterm birth .

            This species has been isolated from both the female genitourinary tract as well as the upper respiratory tract and has been implicated in cases of cellulitis, endocarditis, cervical lymphadenitis, and spontaneous abortions . When compared to GBS, it is associated with increased frequency of PPROM or spontaneous preterm birth and had similar rates of neonatal sepsis or respiratory distress syndrome .   

            Since being isolated, studies have been looking at the resistance profile to determine the best course of treatment. The few studies performed on S. agalactiae have demonstrated that there is low resistance to clindamycin, especially when compared to resistance of GBS to clindamycin . It has also been found to be susceptible to beta-lactam antibiotics, vancomycin and trimethoprim-sulfamethoxazole, with a relatively high rate of resistance to tetracycline . 

In our patient, the primary reason for mortality was most likely severe pulmonary insufficiency from pulmonary hypoplasia due to oligohydramnios.  However Streptococcus porcinus sepsis may have contributed to the rapid deterioration.


Conclusion

            Although there are no pre-existing cases reporting newborn demise secondary to Streptococcus pseudoporcinus sepsis, there is the potential for this species to cause sepsis in a newborn. 

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Richmond University Medical Center
Richmond University Medical Center
Richmond Univercity Medical Center
Richmond University Medical Center
Richmond University Medical Center

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