Late-onset Neonatal Infections Research Articles

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

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). 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 fluidor blood) at Tawam Hospital, Al Ain, Emirate of Abu Dhabi, UAE, from January 2012 and December 2021. Antimicrobial susceptibility analysis was performed. 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%). 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.

Antimicrobial resistance and epidemic clustering of late-onset neonatal infections in a Brazilian intensive care unit.

Nosocomial infections in the neonatal intensive care unit (NICU) tend to cluster and multidrug-resistant (MDR) pathogens are rising in developing countries. We did a retrospective cohort study of neonates admitted to a NICU in Brazil with late-onset neonatal sepsis (LOS) confirmed by blood culture from October 2012 to December 2016 and from July 2018 to December 2021. We defined a cluster of infection when at least two cases of LOS occurred within two different time intervals: 15 and 30 days with the same pathogen in different patients. A random amplified polymorphic DNA (RAPD) was performed from samples from one of these clusters. A logistic regression model was applied having death as the outcome and the infection with an MDR pathogen as the exposure of interest. There were 987 blood cultures from 754 neonates, 621 (63%) were gram-positive cocci, 264 (30%) were gram-negative rods and 72 (7%) fungi. A third of Enterobacterales were resistant to cefepime and a third of non-fermenting glucose rods were resistant to carbapenems. There were 100 or 104 clusters of infection in the 15- or 30-day interval, respectively. A RAPD analysis from an outbreak of MDR Acinetobacter baumannii showed that all five samples belonged to a single clone. An infection with an MDR pathogen was associated with death (OR 1.82, 95% CI 1.03-3.21). In conclusion, clusters of infections in a Brazilian NICU are a frequent phenomenon as seen elsewhere. They suggest cross-transmission of pathogens with increasing antimicrobial resistance and should prompt intensified surveillance and infection control measures.

Late-onset neonatal infections and bacterial multidrug resistance

This study aims to describe bacterial and antimicrobial sensibilities in late-onset healthcare-associated infections (HAIs) with laboratory confirmation in a Neonatal Intensive Care Unit (NICU) of a public hospital in Ceará. This was a cross-sectional study conducted from January 2013 to December 2017. The bacterial types involved in late-onset HAIs, their sensitivity to antimicrobials, and their multidrug resistance were evaluated. The latter was classified according to the criteria revised by the Pan-American Health Organization as multidrug resistance (MDR), extended drug resistance (XDR), or pandrug resistance (PDR). The description of the variables was performed through proportions and frequency distribution depicted in tables. Of the 427 patients with late-onset HAIs, 47 (11.0%) had bacterial infections confirmed by blood cultures, and 7 (14.9%) had infections caused by MDR bacteria. Among the types of bacteria, 26 (55.3%) were Gram-negative bacteria, and 21 (44.7%) were Gram-positive bacteria. Among the Gram-negative bacteria, 92.3% (n=24) showed resistance to more than one antimicrobial, especially to ampicillin (81.2%), cefepime (33.1%), gentamicin (19.4%), and piperacillin/tazobactam (17.2%). Among the MDR ones, three cases had Klebsiella pneumoniae, and three had Pseudomonas aeruginosa, classified as two MDR and one XDR, and three XDR, respectively. Gram-positive resistance to penicillin was the most common one (80.0%), and approximately half of the strains being resistant to oxacillin. Susceptibility was high to vancomycin (97.5%), but one microorganism was resistant to oxacillin and vancomycin. The emergence of MDR strains is a reality in NICUs, carrying the risk of therapeutic failure and requiring continuous prevention protocols aimed at minimizing the risks of contamination by bacteria with high morbidity and mortality.

Bacterial etiology and antibiotic sensitivity patterns in late-onset neonatal blood infection: A 6-year retrospective study

Introduction: The incidence and etiology of neonatal bloodstream infections vary globally. Early appropriate antibiotic therapy is crucial. An empiric antibiotic choice should be driven by accurate knowledge of the local spectrum of pathogens and susceptibilities. Methodology: A retrospective observational study was conducted on neonates born at local tertiary center from January 1, 2013, to December 31, 2018, with late-onset bloodstream infection (LBSI). Trends of causative organisms and antibiotic susceptibilities were analyzed. Results: A total of 696 LBSI occurred in 469 neonates. Overall incidence over the 6 years was 122/1000 admissions. The median time to LBSI was 13 days of life. Majority of infections occurred in infants <32 weeks. About 75.9% were caused by Gram-positive and the rest by Gram-negative bacteria. The most common organism was coagulase-negative staphylococcus (CoNS) which showed an increase in resistance to amikacin over time, but with stable sensitivity patterns to teicoplanin. Klebsiella and Escherichia coli were the most common Gram-negative organisms. There was improving sensitivity to cephalosporin in Klebsiella species. Sixteen percent of Gram-negative isolates were extended spectrum beta-lactamase (ESBL) producing. Majority of the Gram-negative bacteria including ESBL-producing strains remained sensitive to amikacin. An empiric antibiotic combination of teicoplanin and amikacin was appropriate to cover the majority of LBSIs. Conclusions: The majority of late-onset neonatal bloodstream infections in this study cohort were caused by Gram-positive organisms of which CoNS was the most common. The empiric antibiotic choices for LBSI on our unit seem appropriate based on the data. In units where the organism and susceptibility patterns are similar, the same antibiotic choices may be justified.

Bacterial Pathogens and Evaluation of a Cut-Off for Defining Early and Late Neonatal Infection.

Bacterial infections are an important cause of mortality and morbidity in newborns. The main risk factors include low birth weight and prematurity. The study identified the most common bacterial pathogens causing neonatal infections including their resistance to antibiotics in the Neonatal Department of the University Hospital Olomouc. Additionally, the cut-off for distinguishing early- from late-onset neonatal infections was assessed. The results of this study show that a cut-off value of 72 h after birth is more suitable. Only in case of early-onset infections arising within 72 h of birth, initial antibiotic therapy based on gentamicin with ampicillin or amoxicillin/clavulanic acid may be recommended. It has been established that with the 72-h cut-off, late-onset infections caused by bacteria more resistant to antibiotics may be detected more frequently, a finding that is absolutely crucial for antibiotic treatment strategy.

Late-onset Neonatal Infections 1997 to 2017 Within a Cohort in Western Sweden-The Last 21 Years of a 43-Year Surveillance.

The objective of the study was to assess the epidemiology of late-onset (LO) neonatal invasive infections with surveillance covering 43 years, starting from 1975. Observational epidemiologic, retrospective study including a cohort of infants born in western Sweden in 1997-2017, who had a positive blood and cerebral spinal fluid culture between 3 and 120 days of age. A comparison was made of the incidence between 1997-2007 and 2008-2017. Data on LO infections during 3-27 days of life were assessed from 1975. A total of 473 cases of LO infections were registered in 437 patients. The incidence increased from 2.0 to 3.1/1000 live births (LB) between 1997-2007 and 2008-2017 (P < 0.001). The increase in incidence was most pronounced among infants born <28 weeks gestation (from 255 to 398/1000 LB, P < 0.001). The most frequent pathogens were Staphylococcus aureus (25%), coagulase-negative staphylococci (17%), and Escherichia coli (13%). Infections due to group B Streptococci rose from 0.16/1000 LB to 0.33 (P = 0.03). During the whole surveillance period from 1975 to 2017, there were 579 cases between 3 and 27 days of life. Although the incidence increased in 2008-2017 to 1.9/1000 LB after first declining in 1997-2007, the case-fatality rate continued to decline from 27/284 (9.5%) between 1975 and 1996 to 6/182 (3.3%) in 2008 and 2017 (P = 0.01). The incidence of LO neonatal invasive infections increased during the study period (1997-2017), but the case-fatality rate remained lower than in the previous surveillance period (1975-1996). Further surveillance and interventions with focus on prevention is critical to counteract the increasing incidence among high-risk infants.

Protective effect of Group B Streptococcus type-III polysaccharide conjugates against maternal colonization, ascending infection and neonatal transmission in rodent models

Group B Streptococcus (GBS) is a normal inhabitant of recto-vaginal mucosae in up to 30% of healthy women. Colonization is a major risk factor for perinatal infection which can lead to severe complications such as stillbirth and neonatal invasive disease. Intra-partum antibiotic prophylaxis in colonized women is a safe and cost-effective preventive measure against early-onset disease in the first days of life, but has no effect on late-onset manifestations or on early maternal infection. Maternal immunization with capsular polysaccharide-based vaccines shows promise for the prevention of both early-onset and late-onset neonatal infections, although ability to prevent maternal colonization and ascending infection has been less studied. Here we investigated the effect of a GBS glycoconjugate vaccine since the very early stage of maternal GBS acquisition to neonatal outcome by rodent models of vaginal colonization and ascending infection. Immunization of female mice and rats with a type III glycoconjugate reduced vaginal colonization, infection of chorioamniotic/ placental membranes and bacterial transmission to fetuses and pups. Type III specific antibodies were detected in the blood and vagina of vaccinated mothers and their offspring. The obtained data support a potential preventive effect of GBS glycoconjugate vaccines during the different stages of pregnancy.

Serotype distribution and clinical correlation of Streptococcus agalactiae causing invasive disease in infants and children in Taiwan.

Streptococcus agalactiae, or group B Streptococcus (GBS), remains to be one of the leading pathogens causing invasive infections in infants. The clinical GBS isolates from sterile sites of patients younger than 18 years old were collected from October 1998 to December 2014 in two hospitals in Taiwan. Medical records were retrospectively reviewed. Every isolate was serotyped with a multiplex PCR assay. Multilocus sequence typing (MLST) was performed in representative isolates of different serotypes. A total of 205 GBS isolates were collected from 181 patients with 182 infection episodes. Serotype Ia was the most common in patients less than 72h old, whereas III the most common in patients older than 72h. In early-onset disease (0-6 days), Ia and III each caused 27.5% of the infection, followed by Ib (14.5%). In late-onset disease (7-89 days), serotype III predominated (75.3%), followed by Ia (10.1%) and Ib (6.8%). Thirty-one episodes (17%) were complicated with culture-confirmed meningitis. We compared serotype Ia and III patients, and found that serotype Ia patients were significantly younger (median age, 3 days), had more perinatal maternal fever and higher mortality. ST17 and ST19 were exclusively found in serotype III, while ST23 and ST24 comprised of 85% of serotype Ia. In Taiwan, serotypes Ia and III are the most common cause for early-onset and late-onset neonatal GBS infections, respectively. Some differences in the clinical features of invasive GBS infections caused by serotype Ia and III were observed.

Effect of antibiotic use on antimicrobial antibiotic resistance and late-onset neonatal infections over 25 years in an Australian tertiary neonatal unit

BackgroundAntibiotic resistance is a worldwide problem. We describe 25 years of responsible antibiotic use in a tertiary neonatal unit.MethodsData on neonatal infections and antibiotic use were collected prospectively from 1990...

Sepsis From the Gut: The Enteric Habitat of Bacteria That Cause Late-Onset Neonatal Bloodstream Infections

Late-onset sepsis is a major problem in neonatology, but the habitat of the pathogens before bloodstream invasion occurs is not well established. We examined prospectively collected stools from premature infants with sepsis to find pathogens that subsequently invaded their bloodstreams, and sought the same organisms in stools of infants without sepsis. Culture-based techniques were used to isolate stool bacteria that provisionally matched the bloodstream organisms, which were then genome sequenced to confirm or refute commonality. Of 11 children with late-onset neonatal bloodstream infections, 7 produced at least 1 stool that contained group B Streptococcus (GBS), Serratia marcescens, or Escherichia coli before their sepsis episode with provisionally matching organisms. Of 96 overlap comparison subjects without sepsis temporally associated with these cases, 4 were colonized with provisionally matching GBS or S. marcescens. Of 175 comparisons of stools from randomly selected infants without sepsis, 1 contained a GBS (this infant had also served as an overlap comparison subject and both specimens contained provisionally matching GBS). Genome sequencing confirmed common origin of provisionally matching fecal and blood isolates. The invasive E. coli were present in all presepticemic stools since birth, but gut colonization with GBS and S. marcescens occurred closer to time of bloodstream infection. The neonatal gut harbors sepsis-causing pathogens, but such organisms are not inevitable members of the normal microbiota. Surveillance microbiology, decolonization, and augmented hygiene might prevent dissemination of invasive bacteria between and within premature infants.

Group B streptococci in milk and late neonatal infections: an analysis of cases in the literature

BackgroundThe source for late-onset neonatal infections (LONI) due to group B Streptococcus (GBS) has not been fully explored. We reviewed GBS LONI cases associated with contaminated breast milk to determine...

Neonatal infections caused by &lt;i&gt;Escherichia coli&lt;/i&gt; at the National Hospital, Abuja: a three-year retrospective study

Background: Escherichia coli (E.coli) has been implicated as a common cause of both early and late onset neonatal infections. The emergence of different strains of E.coli that are multiply resistant to commonly used antibiotics has made continuous antibiotics surveillance relevant. Knowledge about common infections caused by E.coli as well as its antibiotics susceptibility pattern will guide paediatricians in choosing appropriate antibiotics for empirical treatment of neonatal infections. Methods: A retrospective study of E.coli neonatal infections in NHA was conduct for the period 1st January 2010 to 31st December 2012. The records of all specimens submitted to the Medical Microbiology laboratory within the neonatal period (first 28 days of life) were examined and data about E.coli isolates and their antibiotics susceptibility pattern were retrieved and evaluated. Results: 251(33.2%) bacteria were isolated out of a total of 757 specimen submitted for analysis within the period under review. 17(6.8%) were E.coli; 16 were from soft tissue specimen and one from blood. There was no isolate of E.coli from CSF. Most of the isolates were resistant to commonly used antibiotics for treatment of neonatal infections. Three isolates were resistance to amoxicillin-clavulanate and ceftriaxone. One isolate was resistance to amoxicillin-clavulanate, ceftriaxone and imipenem. 100% and 80% of the strains tested were susceptible to amikacin and imipenem respectively. Conclusion: E.coli is third among the gram negative bacteria isolated within the period under review. Most of them were resistant to commonly used antibiotics for treating neonatal infections but, susceptible to amikacin and imipenem. There is need for regular antibiotics resistance surveillance and stewardship. Keywords: Neonates, E.coli Infections, Antibiotics Resistance, Abuja.

Characteristics of neonatal GBS disease during a multicentre study (2007-2010) and in the year 2012.

The characteristics of Group B Streptococcal (GBS) early onset (EOD) and late onset (LOD) neonatal infections in Italy were analyzed. Two periods were considered, a first 3-years period (2007-2010), when notification of GBS infections was enforced under the auspices of the Italian Ministry of Health, and a second 1 year period (2012) when reporting on neonatal GBS disease continued on voluntary basis. A standardized form was used to collect data on cases of neonatal GBS disease. They included both maternal and neonatal data. The two surveys underlined that preterm deliveries, precipitous labor and negatively GBS screened mothers are common causes of EOD occurrence, possibly explained by inadequate, or lack of, intrapartum antibiotic prophylaxis. Nevertheless, measures for reducing prevention failures and EOD incidence by an higher adherence to prevention strategies, as the Centre for Disease Control recommendations, are still possible and should be encouraged.

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

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

Incidence, aetiology and resistance of late‐onset neonatal sepsis: A five‐year prospective study

Investigate the incidence, etiological pattern and the antimicrobial resistance of late-onset neonatal infections over a period of 5 years. Longitudinal audit of neonatal sepsis from January 2005 to December 2009, in the main maternity hospital in Kuwait. Late-onset neonatal infection was defined as the culture of a single potentially pathogenic organism from blood or cerebrospinal fluid from an infant older than 6 days in association with clinical or laboratory findings consistent with infection. The overall incidence was 16.9 (95% confidence interval: 15.8-18.0) episodes per 1000 live births. The commonest pathogen was coagulase-negative Staphylococcus, 339 (35.7%), while Klebsiella was the most common gram-negative infection, 178 (18.8%). Escherichia coli, Enterococcus and Enterobacter spp were each responsible for 6% of all infections. Candida caused 104 (11.0%) infections. The general pattern of infection remained unchanged over the study period. Case fatality was 11.7% (95% confidence interval: 9.7-13.9%) and was high for Pseudomonas (18.4%) and Candida (22.1%) infections. Approximately 24 and 20% of Klebsiella infections were resistant to cefotaxime and gentamicin, respectively, while 28 and 24% of Escherichia coli infections were resistant to cefotaxime and gentamicin, respectively. The incidence of late-onset infection in Kuwait is high, resembling that in resource-poor countries. The high incidence coupled with low case fatality provides an example for settings where tertiary care is introduced without strict measures against nosocomial infections. Prevention against nosocomial infections in neonatal units has the potential to further reduce neonatal mortality in these settings.

Late-onset neonatal infections: incidences and pathogens in the era of antenatal antibiotics

Widespread use of intrapartum antimicrobial prophylaxis has significantly reduced the incidence of early-onset neonatal infection (EONI); however, little is known about the effects of increased maternal exposure to antibiotics on late-onset neonatal infection (LONI). This study aims to evaluate LONI epidemiology in our region after the application of French recommendations and to determine whether LONI-causing organisms and their antibiotic susceptibility are influenced by peripartum antibiotic exposure. We performed a prospective epidemiologic study of 139 confirmed and possible cases of bacterial LONI in patients treated with antibiotics for at least 5 days of the 22,458 infants born in our region in the year 2007. The overall incidence of LONI caused by all pathogens, Group B streptococcus (GBS) and Escherichia coli (E. coli) were 6.19, 0.36 and 2.72, respectively, per 1,000 live births. Our findings revealed three major types of LONI: E. coli-induced urinary tract infection (UTI) among term infants, coagulase negative Staphylococcus septicemia affecting preterm infants, and GBS infections with severe clinical presentation. Univariable analysis revealed that maternal antibiotic exposure was significantly associated with the risk of amoxicillin-resistant E. coli infection (p = 0.01). Postnatal antibiotic exposure was associated with an increased risk of E. coli LONI (p = 0.048). This link persisted upon multivariable analysis; however, no additional risk factors were identified for LONI caused by antibiotic-resistant E. coli. Our findings confirm that despite the benefits of antenatal antibiotics, this treatment can increase the risk of antibiotic-resistant cases of LONI. National and international surveillance of LONI epidemiology is essential to assess benefits and potential negative consequences of perinatal antibiotic exposure.

Characteristics of Invasive Staphylococcus aureus in United Kingdom Neonatal Units

In industrialized countries, Staphylococcus aureus (SA) is a leading cause of late-onset neonatal sepsis. Culture-proven episodes were identified prospectively from neonatal units participating in the neonatal infection surveillance network. Demographic, risk factor, and outcome data were collected. Between 2004 and 2009, there were 117 episodes of SA infections (including 8 methicillin-resistant SA) in 116 infants from 13 units. The median gestational age and birth-weight were 27 weeks (90% ≤ 37 weeks, 85% ≤ 32 weeks) and 850 g (90% ≤ 2500 g), respectively. The overall incidence was 0.6 per 1000 live births and 23/1000 in infants <1500 g. Most episodes (94%) occurred more than 48 hours after birth (late onset). There were 7 early-onset episodes (< 48 hours) (median gestational age, 38.5 weeks), all due to methicillin-susceptible SA. At the time of culture, 67 of 95 (71%) infants were receiving respiratory support and 47 of 94 (50%) had a central line in situ. The majority of infants had nonspecific clinical features although evidence of focal infection (skin, soft tissue, bone, joint, or pneumonia) was ultimately seen in 41 of 91 (45%). There were 18 deaths, 4 (all late onset) directly due to methicillin-susceptible SA sepsis (4.4%). SA is the second most common pathogen causing late-onset neonatal infections in this neonatal network. Infants who weigh < 1500 g in intensive care settings are the most vulnerable group. Clinical signs are not sufficiently distinctive to allow targeted therapy, suggesting that an antistaphylococcal agent should be part of empiric therapy for late-onset sepsis in premature infants.

1404 What is the Most Appropriate Antibiotic to Treat Late Onset Neonatal Infections?

Introduction: Late onset neonatal infection (systemic infection after 48 hours) is an important cause of morbidity and mortality in neonates. Coagulase negative staphylococci (CoNS) is responsible for more than half of these infections but there is no consensus on the most effective antibiotics. Aim: To evaluate the efficacy and suitability of our antibiotic guideline to treat late onset neonatal sepsis and to compare our guidelines with other level 3 neonatal units in UK. Methods: A list of all positive blood culture results were obtained from microbiology department over one year period (June 2008-June 2009). The notes of these babies were reviewed. We also collected data on the antibiotics used in other tertiary NICU in the UK for late onset sepsis. Results: A total of 22 babies were identified with positive blood cultures during their stay in NICU over 1 year period. 18 of these (81%) had grown CONS and 4 grew other organisms including Group B Streptoccci, enterococci and staphylococcus aureus. Of those that grew CoNS, all were sensitive to Vanocomycin. 13/18 (72%) were resistant to flucloxacillin and 10 (55%) were resistant to Gentamycin. Conclusion: Our study indicates that the most commonest organism isolated is CoNS. There is widespread resistance to flucloxacillin and gentamicin. Vancomycin is sensistive in all cases but its use is reserved due to concerns regarding development of resistance. The antibiotics used will depend on the prevalent micro organisms in the area and their resistance. Neonatalologists will need to work with Microbiologists to develop local guidelines.

Urgences vitales chez le moins d’un mois

Emergencies occurring after maternity discharge in near-term or full-term newborns are infrequent (1%) but life-threatening. A survey has been performed in the Paris area covering: 1) Maternities and Pediatric Emergencies ; 2) SAMU/SMUR (medical emergency system) ; and 3) PMI (medico-social primary centers) in 2001 and 2002. The rate of re-admission after discharge at D3-D4 was 2%. The Emergency Medical Service call incidence was 1%, and a medicalized ambulance was directly sent to the home in one out of ten calls. The call for medical assistance and emergency visits occurred mostly between D13 and D16, for the following reasons: fever, malaise, respiratory or gastrointestinal symptoms. The infants who have required EMS activation had a more severe pathology and poorer prognosis. Given the results of these studies and the ongoing debate in the literature over early maternity discharges, the most frequent etiologies are detailed with their appropriate management. Late-onset neonatal infections and congenital cardiopathies carry the most severe prognosis. Respiratory symptoms primarily due to RSV bronchiolitis requires hospitalization. Child abuse should not be forgotten. Thus, careful evaluation before discharge and appropriate follow-up are essential for a good outcome.

Six-month multicenter study on invasive infections due to group B streptococci in Argentina.

There is little information about invasive infections by group B streptococci (GBS) and their antimicrobial susceptibilities in Latin America. We performed a prospective multicenter study to determine the serotype distribution and the antimicrobial susceptibility of GBS in Argentina. We identified 58 cases, but only 44 had sufficient data to be evaluated. Eight early-, four late-, and one fatal late, late-onset neonatal infections due to GBS were found. A total of 31 patients were adults with bacteremia, skin and soft tissue infections, osteomyelitis, arthritis, meningitis, abdominal infections, and renal abscess. Serotype III was prevalent in late-onset neonatal disease, and several serotypes (Ia/c, III, Ia, and II) were involved in early-onset neonatal infections. Serotypes II, Ia/c, III, and IV were commonly found in adults, with serotype II prevalent in younger adults (18 to 69 years old) and serotype Ia/c prevalent in elderly adults (>70 years old). The mortality rate attributable to GBS infections was 10.8%. All GBS were susceptible to penicillin and ceftriaxone. Resistance to clindamycin (1.7%), erythromycin (5.2%), azithromycin (5.2%), minocycline (69%), and tetracycline (72.4%), to high levels of kanamycin and amikacin (1.7%), and to intermediately high levels of gentamicin (1.7%) was observed. The bifunctional enzyme AAC6'-APH2" was detected in the isolate resistant to aminoglycosides, and other genetic determinants were identified in other resistant isolates: tetM and tetO in tetracycline-resistant streptococci and mefA and ermTR for efflux-mediated and inducible macrolide-lincosamide-streptogramin B-resistant streptococci, respectively. For clinical purposes and rapid and easy detection of high-level aminoglycoside-resistant GBS, a screening method that used 1,000- micro g kanamycin disks is proposed.