Outcome after acute osteomyelitis in preterm infants

Hypogammaglobulinemia Causing Multiple Abscesses and Osteomyelitis of Calcaneus Following a Heel Puncture in a Preterm Neonate

Osteomyelitis is a challenging diagnosis for a neonate. It might result from hematogenous spread or direct extension of a skin infection. The most common organism is Staphylococcus aureus. Preterm infants are at high risk for osteomyelitis because of their immature immune system, hypogammaglobulinemia, frequent blood draws, and invasive monitoring and procedures. We report a case of a male neonate born at 29 weeks by cesarean section, requiring intubation and transfer to the neonatal intensive care unit (NICU). At 34 weeks, he was noted to have an abscess in the lateral aspect of the left foot, which required incision, drainage, and antibiotic coverage of cefazolin as S. aureus was sensitive to penicillin. Four days later (34 + 4 weeks), a left inguinal abscess was noticed, which grew Enterococcus faecium on drainage, which is considered a contaminant initially, but one week later, another left-sided inguinal abscess was noticed growing E. faecium, and the patient was subsequently treated with linezolid. Immunoglobulin levels were found to be low for IgG and IgA. After two weeks of antibiotics, a repeat x-ray of the foot demonstrated changes likely due to osteomyelitis. The patient received seven weeks of antibiotics targeting methicillin-sensitive staphylococcus and three weeks of treatment with linezolid for an inguinal abscess. A repeat x-ray of the lower left extremity after the patient received one month of antibiotics in an outpatient setting showed no signs of acute osteomyelitis in the calcaneus. Immunoglobulin levels continued to be low during the outpatient immunology follow-up. During the third trimester of pregnancy, the transfer of maternal IgG across the placenta begins, leading to lower IgG levels in premature infants and predisposing them to severe infections. The usual site of osteomyelitis is the metaphyseal region of the long bones, but any bone can be affected. The depth of penetration of the puncture site during routine puncture of the heel can cause a local infection. Early x-rays can aid in diagnosis. Antimicrobial treatment is frequently administered intravenously for two to three weeks and then switched to oral medication.

Bone and joint infections in infants under three months of age

AIM

Studies on bone and joint infections (BJI) in infants under three months are rare. We described the clinical and paraclinical features and outcomes of infants hospitalised with BJI under three months of age.

METHODS

The French National Hospital Discharge Database provided data on BJIs in infants under three months of age from January 2004 to 2015 in three Parisian Paediatric teaching hospitals.

RESULTS

We included 71 infants under three months of age with BJI, the median age was 25 days, and the interquartile range (IQR) was 17-43 days. The most common infection sites were the hip (32%) and knee (32%). Symptoms included pain (94%), limited mobility (87%) and/or fever (52%). There were 11 (15.5%) cases of nosocomial BJI. A pathogen was identified in 51 infants (71.8%), including Streptococcus agalactiae (45%), Staphylococcus aureus (22%) and Escherichia coli (18%). The initial median C-reactive protein test rate was 31 mg/L (IQR 17-68). Of the 34 infants followed for more than one year, four developed severe orthopaedic conditions such as epiphysiodesis, limb length discrepancy, bone necrosis and/or impaired limb function.

CONCLUSION

Streptococcus agalactiae was the most common cause of BJI in infants under three months. Orthopaedic sequelae were rare, but severe, and required long-term follow-up.

Methicillin-resistant Staphylococcus aureus mandibular osteomyelitis in an extremely low birth weight preterm infant

Methicillin-resistant Staphylococcus aureus (MRSA) is an established nosocomial pathogen with frequent multidrug resistance. The immaturity of the immune system along with intravascular lines and empirical antibiotic treatments place hospitalized preterm infants at major risk of MRSA infection.

We report a case of MRSA mandibular osteomyelitis complicating a persistent S. aureus bacteremia in a 23-week preterm infant. From the first weeks of life, the infant showed recurrent C-reactive protein (CRP) elevation, associated with S. aureus bacteremia. Antibiotic courses, including vancomycin and linezolid, were performed with transitory normalization of blood parameters. On day 74, the infant suddenly deteriorated and showed a significant increase of both CRP and procalcitonin. Empiric vancomycin and piperacillin-tazobactam treatment was started; nevertheless, she developed a progressive hard swelling of neck and mandible. Radiological evaluation revealed a mandibular osteomyelitis complicated by an abscess, whose culture grew MRSA. Vancomycin was thus changed to teicoplanin and complete clinical and radiological healing was gradually achieved.

In the presence of major risk factors, persistent bacteremia and nonspecific symptoms, a localized focus of infection should be suspected. Microbiological diagnosis should always be attempted and antibiotic treatment should be guided by both susceptibility results and clinical response.

Gram-negative neonatal osteomyelitis: two case reports

Neonatal osteomyelitis is a rare and challenging diagnosis, particularly in the early onset period. Neonatal osteomyelitis is predominantly caused by Staphylococcus aureus with single bone involvement. Here, we report two cases of neonatal osteomyelitis in premature infants caused by Klebsiella pneumoniae with multiple bone lesions. Both cases presented with sepsis and meningitis and were initially diagnosed by incidental findings on plain films, with follow-up bone scan imaging. In both cases, diagnosis was timely and treatment was successful. These cases highlight the need to include neonatal osteomyelitis in the differential diagnosis when late-onset or prolonged neonatal sepsis is present, particularly because long-term outcome is dependent on rapid diagnosis and initiation of treatment.

Fusidic acid in bone and joint infections

The prominence of staphylococci as the causative agent in bone and joint infections suggests that fusidic acid (FA) has a potentially important role in their treatment. FA has been studied in a broad range of orthopaedic infections, mostly in combination with other antimicrobials. For susceptible organisms, particularly Staphylococcus aureus, it has demonstrable efficacy in acute osteomyelitis, chronic osteomyelitis, specialised forms of osteomyelitis such as calcaneal and vertebral infection, septic arthritis, prosthetic and other device-related infections. A small number of studies have also examined the use of FA alone for the treatment of bone infections, with evidence of good efficacy, as well as the local application of FA in plaster-of-Paris (POP) beads, or incorporated into bone cement, again with promising results. Further studies are required to confirm the efficacy of FA in the treatment of orthopaedic infections caused by methicillin-resistant strains of S. aureus.

Acute osteomyelitis and septic arthritis in the neonate, risk factors and outcome

Twenty-two neonates with acute osteomyelitis (AO) or septic arthritis (SA) were included in a study based on a review of medical reports and a long-term clinical and radiological follow up. Clinical symptoms, bacteriology, risk factors, and outcome are discussed. The diagnoses were difficult, the clinical symptoms vague, fever rare and white cell count normal. Detection by plain radiological films was more efficient than by radionuclide bone scan. Staphylococcus aureus was the predominant causative organism and a shift towards group B Streptococcus in recent years was not identified. Risk factors for AO and SA were prematurity (13/22), respiratory distress syndrome (15/22) and perhaps most important: umbilical artery catheterisation (15/22). Severe sequelae were found in only 1 patient, while 3 patients had slight asymptomatic changes. The relatively favourable long-term outcome is unexplained, but may be related to early and appropriate, long lasting antibiotic treatment.

Klebsiella septicaemia, osteomyelitis and septic arthritis in neonates in Ibadan, Nigeria

An outbreak of skeletal infections associated with neonatal Klebsiella septicaemia seen over a 6-month period at the Special Care Baby Unit, University College Hospital, Ibadan is reported. It involved 12 neonates, and the significant antecedent events included perinatal asphyxia, fetal distress and prolonged rupture of membranes. All the babies had septic arthritis and ten cases had osteomyelitis in addition: multiple joint involvement occurred in 50% of cases. All the babies exhibited severe systemic disturbance and the Klebsiella isolated demonstrated multiple antibiotic resistance. The epidemic coincided with a period of severe water shortage which affected the hospital. The probable nosocomial acquisition of the infection is highlighted.