No increase in rates of early-onset neonatal sepsis by non-group B Streptococcus or ampicillin-resistant organisms

[Prevention of Neonatal Group B Sreptococcal Infection. Spanish Recommendations. Update 2012. SEIMC/SEGO/SEN/SEQ/SEMFYC Consensus Document]

Group B streptococci (GBS) remain the most common cause of early onset neonatal sepsis. In 2003 the Spanish Societies of Obstetrics and Gynaecology, Neonatology, Infectious Diseases and Clinical Microbiology, Chemotherapy, and Family and Community Medicine published updated recommendations for the prevention of early onset neonatal GBS infection. It was recommended to study all pregnant women at 35-37 weeks gestation to determine whether they were colonised by GBS, and to administer intrapartum antibiotic prophylaxis (IAP) to all colonised women. There has been a significant reduction in neonatal GBS infection in Spain following the widespread application of IAP. Today most cases of early onset GBS neonatal infection are due to false negative results in detecting GBS, to the lack of communication between laboratories and obstetric units, and to failures in implementing the prevention protocol. In 2010, new recommendations were published by the CDC, and this fact, together with the new knowledge and experience available, has led to the publishing of these new recommendations. The main changes in these revised recommendations include: microbiological methods to identify pregnant GBS carriers and for testing GBS antibiotic sensitivity, and the antibiotics used for IAP are updated; The significance of the presence of GBS in urine, including criteria for the diagnosis of UTI and asymptomatic bacteriuria in pregnancy are clarified; IAP in preterm labour and premature rupture of membranes, and the management of the newborn in relation to GBS carrier status of the mother are also revised. These recommendations are only addressed to the prevention of GBS early neonatal infection, are not effective against late neonatal infection.

Incidence and distribution of pathogens in early-onset neonatal sepsis in the era of antenatal antibiotics

In 2001 France issued a new set of guidelines for the use of antenatal antibiotics (AA). These guidelines recommended intrapartum antimicrobial prophylaxis (IAP) to prevent group B streptococcal (GBS) disease and AA to prolong pregnancy in the event of preterm premature rupture of membranes (AA for PPROM). This study aims to determine the effects of AA, recommended by national guidelines, on the incidence and distribution of pathogens in early-onset neonatal sepsis (EONS). We performed a population-based, prospective, observational study of level II and III perinatal centres throughout the region of Alsace, a northeastern area of France, between March 2004 and February 2005. The study population included all neonates with confirmed or probable EONS, who were treated with antibiotics for at least 5 days. We analysed exposure to AA, as well as clinical and microbiological data obtained from medical records. A total of 20 131 neonates were born during the study period, and 217 were included in the study. Of these, 24 subjects had confirmed sepsis, 140 had probable sepsis and 53 had possible EONS. The overall incidence of confirmed EONS was 1.19 per 1000 births. The infecting bacteria was GBS in 15 of 24 (62.5%) confirmed EONS cases (incidence: 0.75 per 1000 births) and in 81 of 140 (58%) probable sepsis cases. Escherichia coli was identified in 6 of 24 (25%) cases of confirmed EONS (incidence: 0.3 per 1000 births) and in 30 of 140 (21%) cases of clinical sepsis. Among E. coli infections (n= 36), amoxicillin resistance (n= 18) was statistically linked with AA use (P = 0.045). This link was significant in cases of PPROM (P = 0.015), but not when IAP was administered to prevent GBS disease (P = 0.264). IAP was not performed in 18 of 60 (30%) cases and 32 of 93 (34%) cases, despite positive screening or the presence of risk factors for EONS, respectively. Group B streptococcus remains the predominant pathogen in the era of AA. Aminopenicillin-resistant E. coli infections seem to be linked to prolonged AA in cases of PPROM and appear to preferentially affect preterm infants. Therefore, postnatal treatment strategies should consider this possible effect. Our data indicate that the current policy of GBS maternal prophylaxis is not associated with an excessive risk of pathogen resistance. Considering the high incidence of GBS EONS in our region, possible progress could result from better observance of guidelines. These results strengthen the need for continuation of surveillance.

International perspective on early-onset neonatal sepsis

Infections are a major cause of neonatal death in developing countries. High-quality information on the burden of early-onset neonatal sepsis and sepsis-related deaths is limited in most of these settings. Simple preventive and treatment strategies have the potential to save many newborns from sepsis-related death. Implementation of public health programs targeting newborn health will assist attainment of Millennium Development Goals of reduction in child mortality.

No change in the incidence of ampicillin-resistant, neonatal, early-onset sepsis over 18 years

OBJECTIVE

The objective of this study was to assess the effect of maternal antibiotic exposure on neonatal early-onset sepsis (EOS) rates over an 18-year period.

METHODS

A review was performed of infant and maternal records for all culture- proven cases of EOS in infants delivered at the Brigham and Women's Hospital (Boston, MA) in 1990-2007.

RESULTS

Data were analyzed from 335 EOS cases over periods that differed with respect to hospital policy for intrapartum antibiotic prophylaxis against group B Streptococcus (GBS): 1990-1992 (no prophylaxis); 1993-1996 (risk-based); and 1997-2007 (screening-based). The overall incidence of EOS decreased over these periods (3.70 vs 2.23 vs 1.59 cases per 1000 live births; P < .0001). No change in the incidence of infection with ampicillin-resistant organisms was observed overall or among very low birth weight infants. However, an increased proportion of infections were caused by ampicillin- resistant organisms. Mothers of infants with ampicillin-resistant infections were more likely to have been treated with ampicillin (P = .0001). Overall peripartum antibiotic use increased during the study period primarily because of increased use of penicillin G and clindamycin, with no significant change in the use of ampicillin.

CONCLUSIONS

Predominant use of penicillin G for GBS prophylaxis resulted in decreased incidence of EOS. No change in the incidence of ampicillin-resistant EOS was observed, but resistant cases were associated with peripartum ampicillin exposure. These findings suggest that obstetricians should consider preferential use of penicillin G for GBS prophylaxis.

An overview of the natural history of early onset group B streptococcal disease in the UK

Clinicians need information on the risk of Early Onset Group B Streptococcal disease (EOGBS) for counselling pregnant women and to decide who would benefit most from antibiotic treatment during labour. We carried out a systematic review of the research literature and conducted meta-analyses to obtain estimates for the natural history of EOGBS that are representative of the UK population. The mean rate of colonisation for the UK was 14% and we found weak evidence that the prevalence is increasing over time. Maternal GBS colonisation was more likely in women who delivered preterm compared with at term. Just over one-third of babies born to colonised mothers become colonised with GBS at birth (36%), and 3% of colonised babies develop EOGBS bacteraemia. In the UK, EOGBS constitutes one-third of all early onset bacteraemia due to pathogens, in contrast to one-half in the USA.

Sensitivities of antigen detection and PCR assays greatly increased compared to that of the standard culture method for screening for group B streptococcus carriage in pregnant women

Group B streptococcus (GBS) is a major cause of serious infections in neonates. The 2002 revised guidelines of the Centers for Disease Control and Prevention (CDC) for the prevention of perinatal GBS disease recommend that all pregnant women be screened for GBS carriage at between 35 and 37 weeks of gestation and that intrapartum antibiotic prophylaxis be given to carriers. We studied the performances of four different GBS detection assays in the context of antenatal screening. Between May and August 2004, the 605 vaginorectal swab specimens received at our bacteriology laboratory for GBS antenatal detection were tested by the four assays. The standard culture method was done according to the CDC recommendations. The three experimental assays performed with the growth from the selective enrichment (LIM) broth (Todd-Hewitt broth with 15 mug/ml nalidixic acid and 10 mug/ml colistin) after overnight incubation were a GBS antigen detection assay (PathoDx) and two PCR assays (for cfb and scpB). The most accurate assay was the scpB PCR (sensitivity, 99.6%; specificity, 100%), followed by the cfb PCR (sensitivity, 75.3%; specificity, 100%), GBS antigen detection (sensitivity, 57.3%; specificity, 99.5%), and standard culture (sensitivity, 42.3%; specificity, 100%). The GBS antigen detection assay was found to be more sensitive than the standard culture method, and moreover, the assay has a low cost and is easy to perform in all obstetrical centers which have access to the most basic of diagnostic microbiology services. We believe that antigen detection on incubated LIM broth should replace the standard culture method for screening for GBS carriage at 35 to 37 weeks of gestation. The impact of the greater sensitivities of PCR assays on the diminution of neonatal GBS infections remains to be demonstrated.

Early-onset group B streptococcal disease in the era of maternal screening

BACKGROUND

With the widespread implementation of intrapartum antibiotic prophylaxis (IAP), the rate of early-onset neonatal sepsis and meningitis caused by Streptococcus agalactiae (group B streptococcus [GBS]) has decreased dramatically, especially in term infants. However, cases of GBS disease continue to occur despite IAP and incur significant morbidity and mortality. Inaccurate screening results, improper implementation of IAP, or antibiotic failure all may contribute to persistent disease.

OBJECTIVE

To determine if clinical, procedural, or microbiologic factors influenced persistent early-onset GBS disease (EOGBS) cases in a single large maternity service after the institution of a screening-based protocol for IAP.

METHODS

Retrospective review of all cases of culture-proven EOGBS at the Brigham and Women's Hospital (Boston, MA) from 1997 to 2003. Serotyping and surface protein analyses were performed on available disease isolates.

RESULTS

A total of 67260 infants were live-born during this period. Twenty-five cases of EOGBS (0.37 of 1000 live births) were identified. The overall incidence of EOGBS progressively decreased with different approaches to IAP. Of the 25 cases identified after institution of a screening-based protocol, 17 (68%) occurred in term infants (1 death), and 8 (32%) occurred in preterm infants (3 deaths). Among the mothers of term infants, 14 of 17 (82%) had been screened GBS negative; 1 was GBS unknown. More than half of the mothers of term infants who had screened GBS negative (8 of 14) had intrapartum risk factors for neonatal infection but did not receive antibiotics before delivery. Ten of the 17 term infants were evaluated for infection because of clinical signs of illness, and the remainder were evaluated because of intrapartum sepsis risk factors. Of the mothers of preterm infants, by the time of delivery 3 of 8 had been documented as GBS positive, 2 of 8 had been documented GBS negative, and 3 of 8 remained unknown. Only 1 of 25 women received adequate IAP, but the isolate was resistant to the administered antibiotic (clindamycin). Antibiotic resistance was not a factor in any other case, and no dominant serovariant was identified among tested isolates. Procedural errors (lack of recognition of documented GBS colonization or failure to evaluate infants at risk for sepsis) were identified in 4 cases.

CONCLUSIONS

The majority of the remaining cases of EOGBS occurred in infants whose mothers screened negative for GBS colonization. Even in the setting of a maternal GBS-screening program, efforts to evaluate and treat infants with intrapartum clinical risk factors for early-onset sepsis remain important. Until effective vaccines against GBS are available for clinical use, development and implementation of rapid and sensitive techniques for screening for GBS status and antibiotic susceptibility at presentation may help prevent additional cases of invasive GBS disease.

Comparison of early-onset neonatal sepsis caused by Escherichia coli and group B Streptococcus

OBJECTIVE

The purpose of this study was to compare maternal characteristics and neonatal morbidity and mortality rates that are associated with early-onset neonatal sepsis that is caused by group B Streptococcus and Escherichia coli.

STUDY DESIGN

This was a retrospective review of newborn infants with a positive blood culture (and/or cerebrospinal fluid) that was positive for either E coli or group B Streptococcus during the first week of life. Data were abstracted from maternal and neonatal medical records.

RESULTS

Among 28,659 deliveries during the study period, 102 episodes of early-onset neonatal sepsis were identified, 61 of which were caused by group B Streptococcus and 41 of which were caused by E coli. E coli sepsis cases had a lower birth weight, a higher percentage with 5-minute Apgar score <7, and a longer stay in the hospital neonatal intensive care unit and required mechanical ventilation more frequently. Death after early-onset neonatal sepsis with E coli was also more frequent.

CONCLUSION

Early-onset sepsis with E coli is associated with more morbidity and a higher mortality rate compared with early-onset group B Streptococcus.

No increase in rates of early-onset neonatal sepsis by antibiotic-resistant group B Streptococcus in the era of intrapartum antibiotic prophylaxis

OBJECTIVE

The aim of this study was to assess the rate of early-onset neonatal sepsis by antibiotic-resistant group B Streptococcus.

STUDY DESIGN

The time-trend study was conducted at a tertiary care center over the following periods: no protocol for group B Streptococcus prophylaxis (1990 to 1992), risk-based protocol (1993 to 1996), and screening-based protocol (1997 to 2002).

RESULTS

A total of 120,952 neonates were born with 118 cases of group B Streptococcus early-onset neonatal sepsis. The rate of group B Streptococcus early-onset neonatal sepsis decreased significantly (from 2.0 to 1.1 to 0.4 per 1000 births, P < .0001). No group B Streptococcus isolate was resistant to ampicillin, penicillin, cefazolin, or vancomycin. From 1997 to 2002, there were 3 clindamycin-resistant group B Streptococcus isolates (14%). The rate of erythromycin-resistant group B Streptococcus early-onset neonatal sepsis did not change (from 0.14 to 0.03 to 0.08 per 1000 births, P = .6). However, cases of erythromycin-resistant group B Streptococcus early-onset neonatal sepsis accounted for an increasing proportion of the remaining cases of group B Streptococcus early-onset neonatal sepsis (from 7.0% to 2.6% to 23.8%, P = .07).

CONCLUSION

We found no increase in rates of antibiotic-resistant group B Streptococcus early-onset neonatal sepsis.

Antibiotic Prophylaxis and Non–Group B Streptococcal Neonatal Sepsis

OBJECTIVE

To assess the effect of increased use of intravenous penicillin for group B streptococcus (Streptococcus agalactiae, GBS) antibiotic prophylaxis on non-GBS neonatal sepsis and antibiotic resistance.

METHODS

We undertook a nonconcurrent cohort study. Microbiology cultures originating from infants with early-onset neonatal sepsis in our neonatal intensive care unit (NICU) from 1992 to 1999 were reviewed. Prevalence of non-GBS neonatal sepsis in the control period (January 1, 1992, through June 30, 1995) was compared with that in the study period (October 1, 1995, through August 31, 1999), when the protocol changed. Chi-squared or Fisher exact tests were used to determine statistical significance. Resistance patterns were compared in similar fashion.

RESULTS

The prevalence of non-GBS neonatal sepsis was 1.2 per 1,000 (36 of 31,133) live births before and 1.1 per 1,000 (32 of 28,733) live births after institution of the Centers for Disease Control and Prevention culture-based protocol (P = .97). Our power analysis assumed a doubling in the rate of non-GBS sepsis and required 21,220 live births per arm. Gram-negative and gram-positive sepsis prevalences were not significantly different. Escherichia coli and GBS resistance patterns did not change.

CONCLUSION

Institution of a protocol for GBS antibiotic prophylaxis significantly decreased the rate of GBS neonatal sepsis but did not increase the rate of non-GBS neonatal sepsis. Antibiotic resistance patterns of these organisms were not affected.

Effects of intrapartum penicillin prophylaxis on intestinal bacterial colonization in infants

Early-onset group B streptococcal (GBS) infections remain a leading cause of morbidity and mortality in infants. To prevent the vertical transmission of GBS and neonatal GBS infection, guidelines recommend intrapartum penicillin or amoxicillin prophylaxis. This intrapartum antibiotic prophylaxis (IAP) is suspected to favor colonization by antibiotic-resistant bacteria. However, the effects of this prophylaxis on the patterns of acquisition of gastrointestinal bacterial flora in infants have never been studied. We collected stool samples from 3-day-old infants born to mothers who received intrapartum amoxicillin (antibiotic-exposed group; n = 25) and to untreated mothers (non-antibiotic-exposed group; n = 25). The groups were matched for factors known to affect intestinal microbial colonization: gestational age, type of delivery, and type of feeding. Qualitative and quantitative differential analyses of the bacterial flora in stool samples were performed. Similar numbers of infants in the non-antibiotic-exposed and antibiotic-exposed groups were colonized by aerobic bacteria and amoxicillin-resistant enterobacteria (75 and 77%, respectively) (P = 0.79). In contrast, significantly fewer infants in the antibiotic-exposed group than in the non-antibiotic-exposed group were colonized by anaerobic bacteria, especially Clostridium (12 and 40%, respectively) (P < 0.05). Regarding intestinal bacterial colonization, the differences between antibiotic-exposed and non-antibiotic-exposed infants were remarkably few. The only statistically significant effect was the reduced initial bacterial colonization by Clostridium in the antibiotic-exposed group. In our study, the use of IAP did not favor colonization by beta-lactam-resistant bacteria. However, further evaluations are required to highlight the potential risks of the widespread use of antibiotics to prevent early-onset GBS infection.

Ten-year study on the effect of intrapartum antibiotic prophylaxis on early onset group B streptococcal and Escherichia coli neonatal sepsis in Australasia

BACKGROUND

Intrapartum antibiotics have reduced the incidence of neonatal early onset (EO) group B streptococcal (GBS) disease. Some surveillance data suggest that this success may be at the cost of increasing rates of non-GBS infection, especially in premature neonates.

OBJECTIVE

To examine rates of EOGBS infection and EO Escherichia coli neonatal sepsis in Australasia.

METHODOLOGY

Analysis of trends in EO (<48 h age) GBS and E. coli sepsis from longitudinal prospective surveillance data collected from representative tertiary obstetric hospitals in each state of Australia and selected centers in New Zealand during a 10-year period from 1992 through 2001. Statistical analysis used Poisson regression.

RESULTS

206 GBS and 96 E. coli cases occurred in 298,319 live births during the study period. The EOGBS sepsis rate fell from a peak of 1.43/1000 live births in 1993 to 0.25/1000 in 2001 (P < 0.001). The overall EO E. coli sepsis rate was 0.32/1000. In babies with birth weight <1500 g, it was 6.20/1000. There was an overall trend to decreasing EO E. coli sepsis (P = 0.07), and there was no significant change in E. coli sepsis in babies <1500 g (P = 0.60). Sixty-nine percent of E. coli cases occurred in the <1500 g cohort; the case fatality rate in this group was 50%. The overall case fatality rate from E. coli sepsis was 36%, and this rate remained stable during the study period (P = 0.47).

CONCLUSIONS

The increasing use of intrapartum antibiotics produced a steady decline in EOGBS disease in Australasia. There was also a trend to decreasing EO E. coli sepsis in all babies, and the rate in very low birth weight infants remained stable.

Clinical microbiology of bacterial and fungal sepsis in very-low-birth-weight infants

Twenty percent of very-low-birth-weight (<1500 g) preterm infants experience a serious systemic infection, and despite advances in neonatal intensive care and antimicrobials, mortality is as much as threefold higher for these infants who develop sepsis than their counterparts without sepsis during their hospitalization. Outcomes may be improved by preventative strategies, earlier and accurate diagnosis, and adjunct therapies to combat infection and protect the vulnerable preterm infant during an infection. Earlier diagnosis on the basis of factors such as abnormal heart rate characteristics may offer the ability to initiate treatment prior to the onset of clinical symptoms. Molecular and adjunctive diagnostics may also aid in diagnosing invasive infection when clinical symptoms indicate infection but no organisms are isolated in culture. Due to the high morbidity and mortality, preventative and adjunctive therapies are needed. Prophylaxis has been effective in preventing early-onset group B streptococcal sepsis and late-onset Candida sepsis. Future research in prophylaxis using active and passive immunization strategies offers prevention without the risk of resistance to antimicrobials. Identification of the differences in neonatal intensive care units with low and high infection rates and implementation of infection control measures remain paramount in each neonatal intensive care unit caring for preterm infants.

Intrapartum antibiotic prophylaxis and early-onset neonatal sepsis patterns

Objective: To compare the relative effects of intrapartum antibiotic prophylaxis regimens on patterns of early-onset neonatal sepsis.

Methods: We performed an historical cohort study of 17 187 infants born at our center from September 1993 to February 2000. A risk-based strategy was employed prior to July 1996 and a screening-based strategy was utilized thereafter. Ampicillin was utilized prior to March 1995 and penicillin was used thereafter.

Results: There were 75 cases of neonatal sepsis, 34 (4.10/1000) in the risk-based era and 41 (4.63/1000) in the screening-based era (p = 0.62). There were fewer ampicillin-resistant isolates during the risk-based than the screening-based era (32 versus 61%; p = 0.014). The only significant change in organism-specific sepsis rates was an increase in the rate of infection caused by coagulase-negative staphylococci in the screening-based era (0.36 versus 1.46/1000; p = 0.018), but 75% of infants infected with these organisms were not exposed to ß-lactam antibiotics within 72 h prior to delivery. For the risk- and screening-based eras, respectively, the rates of Gram-negative sepsis (1.21 versus 1.46/1000; p = 0.65) and the proportions of Gram-negative pathogens that were ampicillin-resistant (70 versus 77%; p = 1.0) were similar. The drug employed for prophylaxis did not appear to affect the pattern of sepsis cases.

Conclusion: In our patient population, coagulase-negative staphylococci have become the most common cause of early-onset neonatal sepsis. The cause of this shift in pathogen prevalence is uncertain and seemingly unrelated to intrapartum antibiotic exposure.

Neonatal early onset Escherichia coli sepsis: trends in incidence and antimicrobial resistance in the era of intrapartum antimicrobial prophylaxis

BACKGROUND

Although intrapartum antimicrobial prophylaxis has lowered the incidence of early onset group B Streptococcus (GBS) sepsis, there are concerns that the increased use of antibiotics may raise the incidence of non-GBS antimicrobial-resistant infections. The objective of this study was to determine trends in the incidence and antimicrobial resistance of early onset sepsis caused by Escherichia coli in the era of antimicrobial prophylaxis.

METHODS

All neonates with early onset E. coli infection who were born at La Paz Hospital, Madrid, from January 1, 1992, through December 31, 2002, were identified from a microbiologic register of all neonatal infections. To evaluate the effect of the guidelines for GBS prevention, data were pooled and compared for: 1992 through 1995 (Period 1); 1996 through 1998 (Period 2); and 1999 through 2002 (Period 3).

RESULTS

Early onset E. coli infection was diagnosed in 41 of 84 612 live births. The infection rate did not change significantly during the 3 time periods (0.56, 0.24 and 0.55 per 1000 during Periods 1, 2 and 3, respectively; P = 0.936, linear-by-linear association). The proportion of E. coli infections that were resistant to ampicillin increased significantly among preterm infants, from 25% (1 of 4) in Period 1, to 100% (2 of 2) in Period 2 and to 91% (10 of 11) in Period 3 (P = 0.017, linear-by-linear association), but not among term infants, with 67% (8 of 12) in Period 1, 50% (1 of 2) in Period 2 and 44% (4 of 5) in Period 3 (P = 0.317, linear-by-linear association).

CONCLUSIONS

Although the incidence of early onset sepsis caused by E. coli remained stable during the study period, antibiotic-resistant E. coli infections increased among preterm infants. On the whole these trends are reassuring with respect to GBS prophylaxis. However, the increase in the proportion of ampicillin-resistant infections in preterm infants suggests that continuing evaluation of the risks and benefits of prophylaxis in this group is critical.

Effects of antenatal antibiotics on the incidence and bacteriological profile of early-onset neonatal sepsis. A retrospective study over five years

BACKGROUND

Recommendations for the use of antenatal antibiotics have been widely implemented in the past few years, notably to prevent group B streptococcal disease or to prolong pregnancy in the case of preterm premature rupture of the membranes.

OBJECTIVES

We designed a retrospective study to assess the potential effects of this increasing use of antibiotics on the incidence and bacteriological profile of early-onset neonatal sepsis (EONS).

METHODS

All neonates referred to our department for suspected EONS from January 1 1995 through December 31 1999 were included. Antenatal antibiotic exposure together with clinical and microbiological data from the neonatal period were gathered and analyzed on a yearly basis.

RESULTS

Of the 485 newborns who met the inclusion criteria, there were 101 cases of culture-confirmed sepsis; 339 cases of suspected sepsis and 69 cases of confirmed sepsis involved children born in the hospital, among a total of 16,627 live births registered in our center over the study period. The overall incidence of EONS dropped from 6.8 to 0.6/1,000 births between 1995 and 1999 (p < 0.001), but the rate of group B streptococcal infection decreased much more rapidly than that of non-group B streptococcal infection. We observed a trend towards the emergence of ampicillin-resistant Escherichia coli strains, which were isolated in seven cases. Among E. COLI infections, ampicillin resistance was statistically linked with antenatal antibiotic use (p = 0.025). We also delineated several risk factors associated with these infections.

CONCLUSION

In our center, antenatal antibiotic treatment was effective in reducing the incidence of EONS, but this benefit may come at the cost of favoring the emergence of ampicillin-resistant organisms causing severe neonatal infections. Antenatal and postnatal antibiotic treatment strategies should take this adverse effect into account.

Morganella morganii et infection maternofœtale

Morganella morganii is an opportunistic gram-negative bacterium, resistant to ampicillin, and scarcely involved in early-onset neonatal sepsis.

CASE REPORT

After a premature rupture of the membranes, a pregnant patient received prophylactic amoxicillin per os. She developed chorioamnionitis. Her infant was diagnosed with early-onset sepsis. Maternal and baby's blood cultures grew M. morganii. Both the mother and the infant were successfully treated with a third-generation cephalosporin and an aminoglycoside.

DISCUSSION

The influence of a prior antibiotherapy on the emergence of M. morganii vertical infections is discussed.

The effect of postnatal age on gentamicin pharmacokinetics in neonates

STUDY OBJECTIVE

To determine if gentamicin serum concentrations obtained from newborns on day 2 of life versus days 3-4 yield significantly different pharmacokinetic parameter values.

DESIGN

Retrospective chart review.

SETTING

Neonatal intensive care unit.

PATIENTS

Two hundred and sixty-seven infants who had peak and trough gentamicin serum concentrations determined on days 2, 3, or 4 of life.

INTERVENTION

Determination of peak and trough serum gentamicin concentrations on days 2, 3, or 4 of life.

MEASUREMENTS AND MAIN RESULTS

The elimination rate constant, serum half-life, volume of distribution, and clearance of gentamicin were calculated using a one-compartment pharmacokinetic model. Gestational age, birthweight, gentamicin dosage, peak and trough gentamicin concentrations, and hours after birth at which serum concentrations were drawn were recorded for all infants. Infants were stratified into three groups based on gestational age: 28 weeks or younger, older than 28 weeks but younger than 37 weeks, and 37 weeks or older. Birthweight and calculated pharmacokinetic parameters were compared by 2-tailed Student t test to determine if significant differences existed between pharmacokinetics parameters determined on day 2 of life versus days 3 or 4 within each of the gestational age groups. These analyses revealed only one significant difference between parameters assessed on day 2 versus days 3 or 4: at day 2, the mean trough concentration of gentamicin in infants of gestational age between 28 and 37 weeks was 1.63 +/- 0.44 mg/L, whereas at days 3 or 4, the same parameter for patients of the same gestational age was 1.4 +/- 0.48 mg/L (p=0.005).

CONCLUSIONS

With one exception--elevated trough concentrations in infants in the gestational age group between 28 and 37 weeks--pharmacokinetic parameters calculated using gentamicin serum concentrations determined on day 2 of life are not significantly different from those derived from gentamicin serum concentrations determined on days 3 or 4. This suggests that gentamicin serum concentrations and subsequent dosage adjustments can be determined on day 2 of life.

Intrapartum antibiotics and neonatal invasive infections caused by organisms other than group B streptococcus

OBJECTIVES/STUDY DESIGN

Administration of group B streptococcal (GBS) antibiotic prophylaxis to women in labor has dramatically reduced the incidence of GBS neonatal disease, but there is little information on its impact on neonatal infections caused by other organisms. We conducted a nested case-control study to define the association between maternal intrapartum antibiotics and risk of neonatal non-GBS infection.

RESULTS

In our study population, 114 of 13,224 infants had 115 non-GBS infections. The incidence of non-GBS neonatal infections fell during the study period, ranging from an attack rate of 9.6 per 1000 infants in 1990 to 1992 to 8.0 per 1000 infants in 1996 to 1998, although this trend was not statistically significant (P >.05). The unadjusted association between neonatal infection and GBS prophylaxis was 0.89 (95% CI, 0.29, 2.6) and between neonatal infection and maternal intrapartum antibiotic due to any cause was 1.3 (95% CI, 0.65, 2.8).

CONCLUSIONS

The current policy of GBS maternal prophylaxis does not appear to convey excess risk of non-GBS infection to neonates.

[Decreasing incidence of perinatal group B streptococcal disease (Barcelona 1994-2002). Relation with hospital prevention policies]

INTRODUCTION

To analyze the incidence of perinatal sepsis due to group B streptococcus (GBS) as related to compliance with recommendations for its prevention issued by the Catalan Societies for Obstetrics, for Pediatrics, and for Infectious Diseases and Clinical Microbiology in 1997.

METHODS

The study was conducted from 1994 to 2001 in 10 Barcelona-area hospitals, where 157,848 live infants were born.

RESULTS

GBS disease was diagnosed in 129 neonates. Incidence decreased by 86.1% over the study period, from 1.92 cases per 1000 live births in 1994 to 0.26 per 1000 in 2001 (p < 0.001). Changes in the characteristics of perinatal GBS disease were observed in the 18 cases diagnosed in the last 3 years, the time when prevention policies were operative. The incidence was lower (0.28 per 1000 vs. 1.19 for the previous 5 years, p <.00006), the proportion of mothers without risk factors was greater (77.8% vs. 55.9%, p 5 0.009), and premature neonates were not affected (0% vs. 12.6%, p 5 0.003); nevertheless, mortality was similar (5.5% vs. 4.5%, p 5 0.8). Among these 18 cases of sepsis, 9 can be considered failures inherent to the prevention policy and 9 failures of compliance. Only 3 hospitals had prevention policies in 1994, whereas all 10 used intrapartum prophylaxis based on screening results in 2001.

CONCLUSIONS

A substantial decrease in the incidence of perinatal GBS disease coinciding with the application of prevention measures for this pathology has been registered in 10 participating hospitals over the 1994-2001 period.

Effects of intrapartum antimicrobial prophylaxis for prevention of group-B-streptococcal disease on the incidence and ecology of early-onset neonatal sepsis

Sepsis occurring in the first week of life can be a devastating neonatal problem. Group B streptococci (GBS) and enterobacteriaceae are the main causes of early-onset sepsis in more developed countries. Intrapartum antimicrobial prophylaxis (IAP) has lowered the incidence of early-onset GBS sepsis by 50-80%. However, there are concerns that the use of IAP may select for infections caused by enterobacteriaceae, including some strains resistant to antimicrobials. We explored potential associations between IAP use and changes in the causes of early-onset sepsis. We concluded that there have been substantial declines in the incidence of early-onset infections due to GBS and, in some settings, other bacteria. Increases in the frequencies of non-GBS or antimicrobial-resistant early-onset sepsis have been limited to preterm, low-birthweight, or very-low-birthweight neonates. We propose systematic monitoring of early-onset sepsis, coupled with targeted research, to inform periodic reassessment of prevention strategies.

Risk of resistant infections with Enterobacteriaceae in hospitalized neonates

OBJECTIVE

To determine the risk factors associated with progression from colonization to infection with health care-associated antimicrobial-nonsusceptible Enterobacteriaceae (ANE) in critically ill neonates.

STUDY DESIGN

During a 3-year period (1998 to 2000), surveillance rectal cultures were performed on neonates admitted to our Level III neonatal intensive care unit after a cluster of four cases of ANE infection were identified in 1998. ANE were defined as members of the Enterobacteriaceae family that exhibited nonsusceptibility to ceftazidime or laboratory evidence of extended spectrum beta-lactamase (ESBL) production.

RESULTS

A total of 1,710 patients were admitted to the neonatal intensive care unit during the study period. Of the 1,710 patients 300 (18%) were excluded from the risk factor analysis. Of the 1,410 remaining neonates the incidence of health care-associated ANE colonization was 17% (240 of 1,410 patients), and 14% of the colonized patients (34 of 240 patients) developed ANE infections. Of the 206 ANE-colonized patients who did not develop disease, 60 (29%) harbored ESBL-producing isolates. Of the 34 ANE-infected patients, 14 (41%) yielded growth of ESBL-producing isolates. Multiple logistic regression analysis revealed that colonized neonates with very low birth weights (<1,000 g) and those who had received prolonged exposures to antimicrobial agents were at increased risk of ANE infections.

CONCLUSIONS

Colonization with ANE places hospitalized neonates at risk for development of systemic infections. Very low birth weight (<1,000 g) and prolonged exposure to antimicrobial agents were the only two independent risk factors associated with ANE infection.

Change in epidemiology of health care-associated infections in a neonatal intensive care unit

BACKGROUND

Gram-negative rods (GNR) and species are important causes of health care-associated infections in neonatal intensive care units (NICUs). In prior reports, Gram-positive cocci (GPC) have been identified as the most common pathogens causing nosocomial infections in NICUs.

OBJECTIVE

To describe the epidemiology of health care-associated infections in a Level III NICU at a free-standing children's hospital.

METHODS

All health care-associated infections in neonates from August 1996 to July 2001 were analyzed. Data were collected prospectively by standard surveillance protocols and nosocomial infection site definitions from the National Nosocomial Infection Surveillance system of the Centers for Disease Control and Prevention.

RESULTS

During the 5-year study period, 665 pathogens caused 640 infections in the NICU. GNR were the most common pathogens isolated. Of the 665 pathogens 284 (43%) were GNR, followed by 223 (33.5%) GPC, 106 (16%) fungi and 52 (8%) others. spp. were the most common GNR isolated. Ceftazidime resistance was present in 56 of 81 (69%) isolates. Bloodstream and lower respiratory tract infections were the most common sites of infection. More than one-half of the pathogens (388 of 665) were isolated from neonates weighing < or =1000 g.

CONCLUSIONS

There is a change in the epidemiology of health care-associated infections in our NICU with a predominance of GNR. This change can impact choice of antimicrobials for the empiric treatment of health care-associated infections in high risk neonates.

Group B streptococci during pregnancy and infancy

Group B streptococcus (Streptococcus agalactiae) is still of great relevance in the perinatal period, although maternal antimicrobial prophylaxis has significantly reduced the rate of culture-confirmed invasive infection in neonates. This strategy, however, raises considerable concern because preterm delivery or late-onset sepsis cannot be prevented, and antibiotic resistance is increasing worldwide. Several advances in the development of conjugate vaccines and in research on virulence factors and pathways involved in the immune response to group B streptococcus have been accomplished, some of which might reach clinical practice in the near future.