Neonatal bacteremia: patterns of antibiotic resistance

Microbiological Characteristics and Resistance Patterns in a Neonatal Intensive Care Unit: A Retrospective Surveillance Study

BACKGROUND AND OBJECTIVE

This study aims to assess the prevalence and antimicrobial susceptibility patterns of bacterial infections associated with both early-onset sepsis (EOS) and late-onset sepsis (LOS).

METHODOLOGY

This descriptive retrospective surveillance research was conducted on all neonates admitted to the neonatal ICU with bacterial sepsis, where positive cultures were isolated from sterile sites (either cerebrospinal fluid or blood) at Tawam Hospital, Al Ain, Emirate of Abu Dhabi, UAE, from January 2012 and December 2021. Antimicrobial susceptibility analysis was performed.

RESULTS

The incidence of LOS (94.43%) was higher compared to EOS (5.56%). The most prevalent isolates (59.2%) were gram-positive bacteria, with gram-negative bacteria accounting for 40.8%. The leading isolates included coagulase-negative Staphylococci (CONS, 40.98%), Klebsiella (16.04%), Staphylococcus aureus (8.46%), Escherichia coli (8.24%), Pseudomonas (7.57%), and Group B Streptococcus (GBS, 5.12%). CONS were predominant in LOS cases (42.9%), while GBS was the main pathogen in EOS cases (44%).

CONCLUSIONS

We observed reduced resistance levels of CONS against ampicillin, benzylpenicillin, clindamycin, erythromycin, fusidic acid, gentamicin, oxacillin, rifampicin, and trimethoprim/sulfa. S. aureus exhibited increased resistance to erythromycin, fusidic acid, gentamicin, and levofloxacin, while E. coli demonstrated decreased resistance against cephalothin, gentamicin, and trimethoprim/sulfa. The antibiotics currently employed empirically appear to provide adequate coverage against the most prevalent bacteria causing early- and late-onset neonatal infections.

Neonatal early onset sepsis in Middle Eastern countries: a systematic review

BACKGROUND

Early onset neonatal sepsis (EOS) accounts for a significant portion of neonatal mortality, which accounts for 46% of global under five child mortality.

OBJECTIVE

This systematic review studies the bacterial aetiology of EOS in the Middle East, susceptibility patterns to recommended empirical antibiotic therapy and whether this differs between high-income and middle-income countries in the region.

METHODS

Articles were collected from Medline, Web of Science, the Cochrane Library and Index Medicus for the Eastern Mediterranean Region. The articles included in our systematic review met the following criteria: published after January 2000, data relevant to the Middle East, data specific for early onset sepsis, no language restriction. Data on aetiology and susceptibility were extracted from prospective and retrospective studies. Risk of bias was assessed using the Newcastle-Ottawa Scale. This study focused on EOS but does include data regarding neonatal late-onset sepsis antibiotic susceptibility. The data regarding coagulase-negative Staphylococcus species were excluded from final analysis, as possible contaminants. The protocol for this systematic review was registered on PROSPERO: CRD42017060662.

RESULTS

33 articles from 10 countries were included in the analysis. There were 2215 cases of culture-positive EOS, excluding coagulase-negative Staphylococcus. In middle-income countries, Klebsiella species (26%), Staphylococcus aureus (17%) and Escherichia coli (16%) were the most common pathogens, in contrast to group B Streptococcus (26%), E. coli (24%) and Klebsiella (9%) in high-income countries. Overall susceptibility to ampicillin/gentamicin and third-generation cephalosporin were 40% and 37%, respectively, in middle-income countries versus 93% and 91%, respectively, in high-income countries.

CONCLUSIONS

EOS in middle-income countries was more likely to be due to Gram-negative pathogens and less likely to be susceptible to empirical antibiotic therapy. This has important public health implications regarding neonatal mortality in the Middle East region.

Changing epidemiology and resistance patterns of pathogens causing neonatal bacteremia

To conduct a survey of the local prevalent bacteria and antibiotic resistance in a referral tertiary neonatal intensive care unit (NICU), in order to assess the efficacy of local antibiotic policies. We reviewed all positive blood and cerebrospinal fluid cultures obtained between January 2007 and December 2017 in the NICU of Schneider Children's Medical Center of Israel. Early and late-onset bacteremia were defined as episodes occurring within or after the first 3 calendar days of life respectively. Empiric treatment included ampicillin and gentamicin or piperacillin-tazobactam and amikacin for early or late-onset bacteremia respectively. The prevalence and antibiotic resistance of the bacteria were described and compared over time. Eight hundred and twenty nine of 15,947 (5.2%) newborns had at least one episode of bacteremia; 81 had multiple episodes. The most common bacteria were Escherichia coli (32.35%) and group B Streptococcus (19.11%) or coagulase negative Staphylococcus (CoNS) (60.5%) and Klebsiella sp. (12.4%) in early or late-onset bacteremia respectively. Overall, all Gram-positive bacteria were susceptible to vancomycin and most non-CoNS to ampicillin. Nosocomial vs. vertical bacteremia had increased resistance to ampicillin and cephalosporins. Resistance of nosocomial bacteria to piperacillin-tazobactam was 22.4%, to amikacin 3.3%, and to meropenem 1.8%. Changes over time: Gram-negative bacteria had a significant increase in resistance to cotrimoxazole and piperacillin. The resistance to gentamicin doubled. Our empiric antibiotic regimen covers the most frequent isolates. Amikacin may replace gentamicin for selected sick patients in early-onset bacteremia. Piperacillin-tazobactam should be combined with amikacin until susceptibility is available.

Conventional Versus Prolonged Infusion of Meropenem in Neonates With Gram-negative Late-onset Sepsis: A Randomized Controlled Trial

BACKGROUND

Gram-negative bacteria are associated with significant morbidity and mortality in preterm and term newborns. Meropenem has widespread efficacy and often allows for monotherapy in this group. Prolonged infusion instead of infusion over 30 minutes has been suggested to result in higher microbiologic efficacy.

OBJECTIVE

To compare the clinical and microbiologic efficacy and safety of prolonged infusions versus conventional dosing of meropenem in neonates with Gram-negative late-onset sepsis (GN-LOS).

METHODS

A prospective, randomized clinical trial was conducted in neonates with GN-LOS admitted to neonatal intensive care unit (NICU), Mansoura University Children's Hospital, between August 2013 and June 2015. Patients were randomly assigned to receive either intravenous infusion of meropenem over 4 hours (infusion group) or 30 minutes (conventional group) at a dosing regimen of 20 mg/kg/dose every 8 hours and 40 mg/kg/dose every 8 hours in meningitis and Pseudomonas infection. Clinical and microbiologic success in eradication of infection were the primary outcomes. Neonatal mortality, meropenem-related (MR) duration of mechanical ventilation, MR length of NICU stay, total length of NICU stay, duration of respiratory support (RS), duration of mechanical ventilation, MR duration of inotropes and adverse effects were secondary outcomes.

RESULTS

A total of 102 infants (51 in each group) were recruited. The infusion group demonstrated a significantly higher rate of clinical improvement and microbiologic eradication 7 days after starting meropenem therapy compared with the conventional group. Mortality and duration of RS were significantly less in the infusion group compared with conventional group. Acute kidney injury after meropenem treatment was significantly less in the infusion group compared with the conventional group.

CONCLUSIONS

Prolonged infusion of meropenem in neonates with GN-LOS is associated with higher clinical improvement, microbiologic eradication, less neonatal mortality, shorter duration of RS and less acute kidney injury compared with the conventional strategy.

Statistical research on the bioactivity of new marine natural products discovered during the 28 years from 1985 to 2012

Every year, hundreds of new compounds are discovered from the metabolites of marine organisms. Finding new and useful compounds is one of the crucial drivers for this field of research. Here we describe the statistics of bioactive compounds discovered from marine organisms from 1985 to 2012. This work is based on our database, which contains information on more than 15,000 chemical substances including 4196 bioactive marine natural products. We performed a comprehensive statistical analysis to understand the characteristics of the novel bioactive compounds and detail temporal trends, chemical structures, species distribution, and research progress. We hope this meta-analysis will provide useful information for research into the bioactivity of marine natural products and drug development.

Neonatal sepsis: high antibiotic resistance of the bacterial pathogens in a neonatal intensive care unit of a tertiary care hospital

Objective:

To study the bacterial pathogens causing neonatal sepsis and their sensitivity pattern so that guidelines can be prepared for empirical antibiotic therapy.

Materials and Methods:

We conducted a prospective analysis of all the cases admitted to the neonatal intensive care unit (NICU) of a tertiary care hospital and studied the culture and sensitivity pattern of organisms isolated. The neonates who presented with signs and symptoms of septicemia, with/without pneumonia and/or meningitis were studied and a detailed record of the maturity, age at onset, sex, birth weight (weight on admission for home deliveries), symptoms and signs along with the maternal risk factors was made. The cases with suspect sepsis were screened using various screening markers. Blood culture was done in all the cases, while cerebrospinal fluid was analysed only in those indicated. Sensitivity of the isolated organism was tested by Kirby Bauer disc diffusion techniques and various drug resistance mechanisms were studied.

Result:

Out of the 190 neonates (M:F=1.22:1) admitted to the NICU, 60 (31.57%) shows blood culture positive. Ninety-five percent cases were due to early onset septicemia. Thirty one neonates had Gram negative, twenty seven had Gram positive septicemia and two had candidial infection. Seventy percent Gram-positive isolates were resistant to penicillin. Ninety percent Gram negative isolates were resistant to gentamycin and ampicillin. Carbapenem resistance mechanisms such as ESBL.

Conclusion:

There is an increasing trend of antibiotic resistance to the commonly used and available drugs. Continuous surveillance for antibiotic susceptibility should be done to look for resistance pattern.

Early-onset sepsis in a neonatal intensive care unit in Beni Suef, Egypt: bacterial isolates and antibiotic resistance pattern

PURPOSE

To identify the frequency of bacterial isolates in early-onset neonatal sepsis (EONS) and their antimicrobial resistance pattern.

METHODS

A retrospective study of EONS was conducted at the Beni Suef University Hospital from September 2008 to September 2012. A case of EONS was defined as an infant who had clinical signs of infection or who was born to a mother with risk factors for infection, and in whom blood culture obtained within 72 hours of life grew a bacterial pathogen.

RESULTS

Of 673 neonates screened, there were 138 positive blood cultures (20.5%) (confirmed EONS). Of the recovered isolates, 86.2% were gram-negative pathogens. Klebsiella pneumoniae (42.8%), Enterobacter cloacae (22.5%), and Escherichia coli (13.8%) were the commonest isolated organisms. The most common gram-positive microorganism was Staphylococcus aureus accounting for only 12 isolates (8.7%). All Klebsiella isolates and 93% of Enterobacter isolates were resistant to ampicillin. Gram-negative pathogens had the maximum overall sensitivity to imipenem, cefepime, and ciprofloxacin; whereas, gram-positive isolates were most susceptible to vancomycin, imipenem, and piperacillin.

CONCLUSION

K. pneumoniae was the predominant causative bacteria of EONS followed by E. cloacae and E. coli. There was a high resistance to ampicillin. Imipenem had the maximum overall activity against the causative bacteria. Continuous surveillance is needed to monitor the changing epidemiology of pathogens and antibiotic sensitivity.

Early onset sepsis in very low birth weight newborn infants

Early onset sepsis (EOS) is a severe problem affecting very low birth weight (VLBW) infants and is associated with a threefold increased risk of mortality. Although advances in perinatal care have led to improved survival of VLBW infants over recent decades, survival without major neonatal morbidity has not increased. The authors reviewed the current literature on EOS, focusing on the peculiarities concerning risk factors, etiology, diagnosis, treatment and outcome in very low birth weight infants, and on the recent advances in the management of this condition.

The impact of group B streptococcus prophylaxis on late-onset neonatal infections

OBJECTIVE

To determine trends in late-onset neonatal infections and risk factors for ampicillin/penicillin-resistant microorganisms.

STUDY DESIGN

Data on 584 infants with positive blood, urine or cerebrospinal fluid cultures for bacteria or fungi at 8-30 days of age from 1990 to 2007 were examined and divided into three epochs, based on intrapartum antibiotic prophylactic (IAP) practices. Pathogens and antibiotic resistance were compared among epochs.

RESULT

The number of candidal infections increased over time for the entire population (P=0.006). There was an increased incidence of Gram-negative (P=0.009) and candidal infections (P=0.014) among very low-birthweight infants. Only Escherichia coli infections showed increasing ampicillin resistance over epochs (P=0.006). In regression analysis, ampicillin/penicillin resistance increased with IAP use (odds ratio 2.05).

CONCLUSION

Changing microorganisms and increasing antibiotic resistance in late-onset neonatal infections are likely multifactorial but are increased with IAP use, which may identify an at-risk population. Increasing Candida infections require further investigation.

No change in antibiotic susceptibility patterns in the neonatal ICU over two decades

OBJECTIVES

To identify trends in early-onset sepsis and late-onset sepsis neonatal rates and to evaluate the appropriateness of the empirical antibiotic protocols.

DESIGN

A 17-yr (1993-2009) analysis of positive blood and cerebrospinal fluid cultures.

SETTING

The two neonatal ICUs at the Hadassah- Hebrew University Medical Center.

RESULTS

During this period, 991 infants had at least one episode of either bacteremia or meningitis. The overall incidence of early-onset sepsis was 0.64 per 1,000 live births with a nonsignificant trend over the study period (p = 0.37). The overall incidence of late-onset sepsis was 7.5 per 100 admissions with a significant positive trend in the incidence rates (p = 0.021). The incidence of late-onset sepsis was 7.5 per 100 admissions with a significant positive trend in the prevalence rates (p = 0.021). The prevalence of early-onset group B Streptococcus bacteremia decreased significantly throughout the study period. Among late-onset sepsis, Gram-positive and fungi infection rates were stable over time, while Gram-negative infection rates showed a significant positive trend (p = 0.007). No significant change in the susceptibility rate of the isolated Gram-negative bacteria in late-onset sepsis for the common antibacterial drugs was found. About 85% and 90% of the isolated organisms were susceptible to our early-onset sepsis (ampicillin and gentamicin) and late-onset sepsis (vancomycin and cefotaxime) protocols, respectively, and these rates were stable over the study period (p = .1 and .55, respectively). Sepsis-related mortality was higher among Gram- negative sepsis cases resistant to our empiric antibiotic protocol.

CONCLUSIONS

Our empiric antibiotic protocols are appropriate despite their continuous use over the last 17 yrs. This may have been achieved by the use of a controlled antibiotic program and infection control efforts.

Short versus long infusion of meropenem in very-low-birth-weight neonates

Prolonged infusion of meropenem has been suggested in studies with population pharmacokinetic modeling but has not been tested in neonates. We compared the steady-state pharmacokinetics (PK) of meropenem given as a short (30-min) or prolonged (4-h) infusion to very-low-birth-weight (gestational age, <32 weeks; birth weight, <1,200 g) neonates to define the appropriate dosing regimen for a phase 3 efficacy study. Short (n = 9) or prolonged (n = 10) infusions of meropenem were given at a dose of 20 mg/kg every 12 h. Immediately before and 0.5, 1.5, 4, 8, and 12 h after the 4th to 7th doses of meropenem, blood samples were collected. Meropenem concentrations were measured by ultrahigh-performance liquid chromatography. PK analysis was performed with WinNonlin software, and modeling was performed with NONMEM software. A short infusion resulted in a higher mean drug concentration in serum (C(max)) than a prolonged infusion (89 versus 54 mg/liter). In all but two patients in the prolonged-infusion group, the free serum drug concentration was above the MIC (2 mg/liter) 100% of the time. Meropenem clearance (CL) was not influenced by postnatal or postmenstrual age. In population PK analysis, a one-compartment model provided the best fit and the steady-state distribution volume (V(ss)) was scaled with body weight and CL with a published renal maturation function. The covariates serum creatinine and postnatal and gestational ages did not improve the model fit. The final parameter estimates were a V(ss) of 0.301 liter/kg and a CL of 0.061 liter/h/kg. Meropenem infusions of 30 min are acceptable as they balance a reasonably high C(max) with convenience of dosing. In very-low-birth-weight neonates, no dosing adjustment is needed over the first month of life.

Gastrointestinal colonization with ESBL-producing Klebsiella in preterm babies--is vancomycin to blame?

In this study, we examine the possible association between treatment with vancomycin and colonization with extended-spectrum beta-lactamase (ESBL)-producing Klebsiella in our neonatal intensive care unit (NICU). Variables compared between newborns which developed rectal colonization and those who did not include: gestational age, birth weight, gender, and total length of hospital stay until positive stool culture or discharge, treatment with vancomycin, and positive blood culture for coagulase-negative Staphylococcus. We found that lower birth weight, younger gestational age, and treatment with vancomycin were statistically significant risk factors for gastrointestinal colonization with ESBL-producing Klebsiella. When applying a multivariate model, treatment with vancomycin, both for a full 10-day course and for a short 3-day empirical treatment, remained statistically significant. Treatment with vancomycin is a risk factor for gastrointestinal colonization with ESBL-producing Klebsiella in premature babies.

Early onset neonatal sepsis: the burden of group B Streptococcal and E. coli disease continues

BACKGROUND

Guidelines for prevention of group B streptococcal (GBS) infection have successfully reduced early onset (EO) GBS disease. Study results suggest that Escherichia coli is an important EO pathogen.

OBJECTIVE

To determine EO infection rates, pathogens, morbidity, and mortality in a national network of neonatal centers.

METHODS

Infants with EO infection were identified by prospective surveillance at Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Network centers. Infection was defined by positive culture results for blood and cerebrospinal fluid obtained from infants aged ≤72 hours plus treatment with antibiotic therapy for ≥5 days. Mother and infant characteristics, treatments, and outcomes were studied. Numbers of cases and total live births (LBs) were used to calculate incidence.

RESULTS

Among 396 586 LBs (2006-2009), 389 infants developed EO infection (0.98 cases per 1000 LBs). Infection rates increased with decreasing birth weight. GBS (43%, 0.41 per 1000 LBs) and E coli (29%, 0.28 per 1000 LBs) were most frequently isolated. Most infants with GBS were term (73%); 81% with E coli were preterm. Mothers of 67% of infected term and 58% of infected preterm infants were screened for GBS, and results were positive for 25% of those mothers. Only 76% of mothers with GBS colonization received intrapartum chemoprophylaxis. Although 77% of infected infants required intensive care, 20% of term infants were treated in the normal newborn nursery. Sixteen percent of infected infants died, most commonly with E coli infection (33%).

CONCLUSION

In the era of intrapartum chemoprophylaxis to reduce GBS, rates of EO infection have declined but reflect a continued burden of disease. GBS remains the most frequent pathogen in term infants, and E coli the most significant pathogen in preterm infants. Missed opportunities for GBS prevention continue. Prevention of E coli sepsis, especially among preterm infants, remains a challenge.

The changing spectrum of neonatal infectious disease

To understand the changing spectrum of neonatal infectious disease, one must first be familiar with the history, the variety of organisms and the progression of change of neonatal infections over the years. As progressively more immature neonates are surviving, the spectrum of infectious disease has changed in response to current medical practice responsible for this success and to selective pressures on the microorganisms. The surviving very low birth weight infants are at a significant risk for contracting infections from this expanding repertoire of pathogens. Microorganisms once thought seemingly benign and nonpathogenic are now commonly accepted as pathogens and are among the most likely organisms to cause infections in this extremely vulnerable patient population. When considering the possible identity of infecting organisms and attempting to tailor specific therapies to decrease unwanted consequences, one must consider the level of maturity and the age of neonate, as well as the intensity of care necessary for a successful outcome. This brief review focuses primarily on the changing spectrum of bacterial and fungal infections and will not substantially address viral infections.

Clinical characteristics of nosocomial infections in neonatal intensive care unit in eastern China

A retrospective cohort study on nosocomial infections (NI) in the neonatal intensive care unit (NICU) was performed in the Children's Hospital of Zhejiang University, Hangzhou district, China. The most common infection site was pneumonia and bloodstream infection. Low admission age, long NICU stay, and mechanical ventilation were significant risk factors for NI. Klebsiella pneumoniae was the most common pathogen, followed by Acinetobacter baumannii, Staphylococcus epidermidi, Pseudomonas aeruginosa, Enterobacter cloacae, and Stenotrophomonas maltophilia. Antibiotic resistance of the isolated bacterium was high. In conclusion, this study described the clinical characteristics of NI in a Chinese NICU, which might contribute to implementation of more effective therapeutic and preventive strategies.

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.

Clinical microbiology of early-onset and late-onset neonatal sepsis, particularly among preterm babies

Prematurity has got special challenge for clinicians and also other medical staff, such as microbiologists. Immature host defense mechanisms support early-onset sepsis, which can be very serious with very high mortality. While the past decade has been marked by a significant decline in early-onset group B streptococcal (GBS) sepsis in both term and preterm neonates, the overall incidence of early-onset sepsis has not decreased in many centers, and several studies have found an increase in sepsis due to gram-negative organisms. With increasing survival of these more fastidious preterm infants, late-onset sepsis or specially nosocomial bloodstream infection (BSI) will continue to be a challenging complication that affects other morbidities, length of hospitalization, cost of care, and mortality rates. Especially the very low birthweight (VLBW) infants sensitive to serious systemic infection during their initial hospital stay. Sepsis caused by multiresistant organisms and Candida spp. are also increasing in incidence, has become the most common cause of death among preterm infants. This review focuses on the clinical microbiology of neonatal sepsis, particularly among preterm babies, summarizing the most frequent bacterial and fungal organisms causing perinatally acquired and also nosocomial sepsis.

Colonization and persistence of antibiotic-resistant Enterobacteriaceae strains in infants nursed in two neonatal intensive care units in East London, United Kingdom

Stool samples were collected from infants nursed in two neonatal intensive care units (NICUs) in East London, United Kingdom. The aim of the study was to determine the incidence of and risk factors for the carriage of multiresistant Enterobacteriaceae strains (MRE; resistant to three or more classes of antibiotic) and the extent of the persistence of resistant strains following discharge. Sixty-two (50%) of 124 infants had acquired MRE by 2 weeks of postnatal age, and 69 (56%) infants had acquired MRE by discharge. The proportions of infants at 2 weeks carrying strains that were resistant to antibiotics were the following: tetracycline, 79%; amoxicillin, 78%; cephalosporins, 31%; trimethoprim, 20%; piperacillin-tazobactam, 11%; chloramphenicol, 9%; and aminoglycoside, 4%. A gestational age of less than 26 weeks was a risk factor for colonization with MRE at discharge, but not at 2 weeks. Analysis within a NICU showed that exposure of an infant to a specific antibiotic in the NICU was not a risk factor for the carriage of a strain resistant to that antibiotic. Estimates of persistence from discharge to 6 months were the following: for tetracycline, 57% (95% confidence intervals [CI], 0.35 to 0.87); chloramphenicol, 49% (95% CI, 0.20 to 0.83); trimethoprim, 45% (95% CI, 0.22 to 0.74); piperacillin-tazobactam, 42% (95% CI, 0.20 to 0.71); and augmentin, 34% (95% CI, 0.11 to 0.66). Strains resistant to cephalosporins or aminoglycosides showed lower levels of persistence. Nine of 34 infants (26.5%) with Escherichia coli and 4 (7.1%) of 56 infants with Klebsiella spp. at discharge carried strains indistinguishable by randomly amplified polymorphic DNA and antibiotic susceptibility patterns at 6 months. MRE were found at high frequency in the infants during their stay in the NICU and persisted in a proportion of infants.

A population-based observational study of restrictive guidelines for antibiotic therapy in early-onset neonatal infections

BACKGROUND

The extensive use of broad-spectrum antibiotics has been associated with major changes in the spectrum of organisms involved in early-onset neonatal infection (EONI), their susceptibility to antibiotics, or both. Therefore, guidelines for a more rational use of antibiotics in neonates have been developed. We conducted a population-based observational study to assess the effectiveness and compliance with restrictive guidelines for the antibiotic therapy in EONI.

METHODS

Neonates receiving antibiotics within 72 hours of life were identified prospectively by population-based surveillance in the 18 hospitals of Burgundy, between February 2002 and June 2003. They were treated in accordance with guidelines limiting the use of broad-spectrum antibiotics and shortening the treatment duration. Each neonate included was evaluated for 60 days after birth. An unfavorable outcome was defined as death related to EONI or late-onset infection.

RESULTS

Of the 25,480 infants born during the study period, 1012 received antibiotics at birth. Of these 1012 infants, 39 were definitely infected (septicemia), 288 clinically infected and 685 not infected. The EONI cure rate was 96.8% without infectious relapse. Forty-five infants received a second course of antibiotic therapy. Birth weight (OR: 5.6; 95% CI: 2.2-14.1), mechanical ventilation (OR: 4.1; 95% CI: 1.3-13.1), central venous catheterization (OR: 16.1; 95% CI: 1.8-141.9), and antibiotic therapy duration (OR: 2.5; 95% CI: 1.1-5.5) were independently associated with late-onset infection.

CONCLUSION

Reducing the antibiotic therapy duration does not increase the risk of infectious relapse and may decrease the incidence of late-onset infection.

Clonal variability of group B Streptococcus among different groups of carriers in southern Israel

A high prevalence of maternal group B Streptococcus (GBS) carriage and an extremely low incidence of invasive neonatal disease have been reported from southern Israel. In order to obtain insight into this discrepancy, this study was performed to determine the population structure of GBS from asymptomatic pregnant women living in this area. Seventy-two strains from maternal GBS carriers were characterized using multilocus sequence typing (MLST). Epidemiologic characteristics of the carriers and their newborns, including demographic variables, obstetric status, and general health parameters, were collected by means of a postpartum interview and a review of the relevant medical records. The MLST analysis grouped the bacteria into six different lineages (clonal complexes). Lineage ST-2 was prevalent among Bedouin-Arabs (p=0.01) and lineage ST-22 among Jews (p=0.001). Lineage ST-17 was prevalent among carriers who emigrated after 1997 from western nations of the former USSR (p<0.001). Lineage ST-22 was associated with carriage of surface-protein C (p=0.01) and lineage ST-17 with surface-protein R (p<0.01). Lineage ST-2 was prevalent among consumers of antibiotics (p=0.02) and was associated with erythromycin-resistant strains (p<0.001). Each subgroup of the southern Israeli maternal population has a different distribution of GBS clones. The clones prevalent among the Bedouin-Arabs and the Jews are known to be of low virulence. Lineage ST-17, which is associated with invasive disease, is prevalent among women who emigrated from western Soviet nations. Therefore, a different policy of GBS prophylaxis, resembling the one executed in endemic areas, should be considered in this population.

Neonatal sepsis 1991-2001: prevalent bacterial agents and antimicrobial susceptibilities in Bahrain

OBJECTIVES

To investigate the organisms causing neonatal sepsis and their modifications over an extended period, to assess their changing sensitivities to antibiotics and to verify whether the policy for screening pregnant women for group B streptococci (GBS) carriage is desirable in our settings.

SUBJECTS AND METHODS

Medical records of all infants with positive blood culture from the Neonatal Intensive Care Unit at Salmaniya Medical Complex between 1991 and 2001 and Bahrain Defense Force Hospital between 1999 and 2001 were reviewed.

RESULTS

Of the 7,978 neonates in both hospitals 335 (4.19%) had culture-proven bacteremia. Gram-positive bacteria were isolated at constant rate over the 11-year period. The main agents isolated were coagulase-negative Staphylococcus (CoNS) in 138 cases (41%), Staphylococcus aureus in 28 newborns (8%) and GBS in 26 patients (7.8%, 0.2/1,000 live births). All of them were sensitive to penicillin G, erythromycin and clindamycin. Gram-negative bacteria were declining but Escherichia coli was isolated in 35 cases (10%). Of special concern is the increasing percentage (5.7%) of Candida isolation. No clear trend toward increasing resistance was observed, although a major difference among the two institutions was evident. Klebsiella and Enterobacter spp. showed resistance to many of the antibiotics tested, thereby posing difficult therapeutic choices.

CONCLUSION

Good quality specimens are essential to evaluate the role of CoNS. The increasing threat of fungal infection must be carefully tackled. Specifically tailored policies for GBS prevention must be defined according to the local epidemiology.

Population structure of group B streptococcus from a low-incidence region for invasive neonatal disease

The population structure of group B streptococcus (GBS) from a low-incidence region for invasive neonatal disease (Israel) was investigated using multilocus genotype data. The strain collection consisted of isolates from maternal carriage (n=104) and invasive neonatal disease (n=50), resolving into 46 sequence types. The most prevalent sequence types were ST-1 (17.5 %), ST-19 (10.4 %), ST-17 (9.7 %), ST-22 (8.4 %) and ST-23 (6.5 %). Serotype III was the most common, accounting for 29.2 % of the isolates. None of the serotypes was significantly associated with invasive neonatal disease. burst analysis resolved the 46 sequence types into seven lineages (clonal complexes), from which only lineage ST-17, expressing serotype III only, was significantly associated with invasive neonatal disease. Lineage ST-22 expressed mainly serotype II, and was significantly associated with carriage. The distribution of the various sequence types and lineages, and the association of lineage ST-17 with invasive disease, are consistent with the results of analyses from a global GBS isolate collection. These findings could imply that the global variation in disease incidence is independent of the circulating GBS populations, and may be more affected by other risk factors for invasive GBS disease, or by different prevention strategies.

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.

In vitro combined bactericidal activity of cefpirome and glycopeptides against glycopeptides and oxacillin-resistant staphylococci

Infections caused by coagulase-negative staphylococci are becoming increasingly important, particularly those of nosocomial origin, as the organisms are frequently multi-resistant. New antimicrobial strategies are needed. The bactericidal activity of a combination of cefpirome with either vancomycin or teicoplanin against 12 strains of methicillin-resistant staphylococci with a decreased susceptibility to teicoplanin was determined in vitro by a time killing method. Strains Mu3 and Mu50 of Staphylococcus aureus were also studied. Cefpirome (0.125-0.5 x MIC) combined with vancomycin (0.25-1 x MIC) or teicoplanin (0.125-1 x MIC) acted synergically against 12 isolates over 18 h in most cases. A synergistic killing effect was also observed with the Mu3 and Mu50 strains of glycopeptide-intermediate S. aureus but over a longer period.

Antibacterial drug discovery: is it all downhill from here?

There has been a marked decline in the industrial research aimed at discovering novel antibacterial agents, including new drugs that target resistant organisms. While this decline may reflect past cyclical changes that often affect resource allocation at pharmaceutical companies, this decline is occurring at a time of increasing levels of antibacterial drug resistance and meagre pipelines of new agents that are active against them. There are multiple reasons for this decline, although few are unique to antibacterial drug discovery research. These include: lack of industry productivity, increasing size of clinical trials, increased generic competition and other pressures on drug pricing, a crowded and confused marketplace and industry consolidation. And while many (if not most) large companies and biotechs have exited the field or severely curtailed their research, others have made it a point to continue their efforts, citing both the unmet medical need and a large and apparently growing market. Despite the fact that some companies have remained engaged, the view here is that the current level of industrial effort is insufficient to sustain a healthy flow of new and better agents that are needed to counter the imminent threat of bacterial drug resistance. Therefore, a clear and urgent need for finding ways to improve the level and quality of industrial research in this area is apparent.

Étude de la corrélation entre les prescriptions d’antibiotiques et les recommandations dans une unité de soins intensifs néonatals

The increasing use of wide spectrum antibiotics has been reported to be associated with a greater prevalence of multi-resistant bacteria.

OBJECTIVES

The aims of this study were to survey the use of antibiotics and to evaluate the correlations between patterns of prescription of antibiotics and prescription guidelines in a neonatal intensive care unit.

MATERIAL AND METHODS

In this 6-month study, all newborns admitted to the NICU and treated with antibiotics were included. Data regarding criteria of antibiotic prescription, length of treatment, and criteria of withdrawing treatment were collected. The correlation between prescriptions and guidelines was evaluated a posteriori by a non-prescriber physician. One hundred and sixteen newborns were included, of whom nine had received antibiotics on more than one occasion. Mean gestational age was 33.5 weeks. In 82% of cases, the reason for hospitalisation was respiratory distress syndrome.

RESULTS

Patients received systemic antibiotics for primary infection (78%), nosocomial infection (17%) and postsurgical prophylaxis (5%). Suspected foeto-maternal infections (SFMI) were the dominant features of primary infection (96%). In 49% of cases, suspected infection was not proven and justified withdrawal of treatment within 3 days. Sixty percent of nosocomial infections occurred in newborns with gestational ages of less than 28 weeks. Bacterial criteria were decision-making factors only in nosocomial infections. An absence of observance of guidelines occurred in 9% of treated newborns, and in most cases involved excessive length of treatment.

CONCLUSION

These results show: (1) the majority of antibiotic prescriptions were for not proven SMFI; (2) a low rate of nosocomial infections; (3) the predominance of nosocomial infections in premature newborns; (4) less than 10% of non-observance of guidelines. It appears necessary to develop more precise guidelines to limit antibiotic use and to evaluate them regularly.