Surveillance of Multidrug-Resistant Pathogens in Neonatal Intensive Care Units of Palermo, Italy, during SARS-CoV-2 Pandemic

BACKGROUND

Antimicrobial resistance (AMR) is a topic of concern, especially in high-level care departments like neonatal intensive care units (NICUs). The systematic use of an "active" epidemiological surveillance system allows us to observe and analyze any changes in microbial distribution, limiting the risk of healthcare-associated infection (HAI) development.

METHODS

We have conducted a longitudinal observational study in the five NICUs of Palermo, comparing the "pre-pandemic period" (March 2014-February 2020) with the "pandemic" one (March 2020-February 2022). The primary aim of the study was to evaluate the cumulative prevalence of carriage from multi-drug resistant (MDR) bacteria in the cumulative NICUs (NICU C).

RESULTS

During the "pre-pandemic period", 9407 swabs were collected (4707 rectal, 4700 nasal); on the contrary, during the "pandemic period", a total of 2687 swabs were collected (1345 rectal, 1342 nasal). A statistically significant decrease in MDR-Gram-negative bacteria (GNB) carriage prevalence was detected during the pandemic. At the same time, there was a general worsening of the carriage of carbapenemase-forming MDR-GNB (CARBA-R+) and methicillin-resistant Staphylococcus aureus (MRSA) during the pandemic period. A significant reduction in methicillin-susceptible Staphylococcus aureus (MSSA) carriage was detected too.

CONCLUSIONS

The surveillance of MDRO carriage in NICUs is fundamental for limiting the social and economic burden of HAIs.

Utility of Induced Sputum in Assessing Bacterial Etiology for Community-Acquired Pneumonia in Hospitalized Children

BACKGROUND

Diagnostic testing for bacterial etiology of community-acquired pneumonia (CAP) is insensitive. Induced sputum (IS) is an attractive option for the evaluation of the lower respiratory tract.

METHODS

Children aged 0-18 years with CAP were enrolled in the Etiology of Pneumonia in the Community (EPIC) study between 2010 and 2012. Blood and respiratory specimens were assessed by culture and polymerase chain reaction (PCR). The radiographic CAP was determined by a study radiologist. Sputum was induced with hypertonic saline. IS specimen was high quality (HQ) if Gram stain showed >25 white blood and <10 epithelial cells per low-powered field; all others were low quality (LQ). We compared IS pathogen prevalence between HQ and LQ IS, and by radiographic pneumonia. Pathogen concordance with EPIC etiology was assessed. Length of stay (LOS) was compared by receipt of IS pathogen-concordant antibiotics.

RESULTS

Out of 977 children, 916 (94%) children enrolled in Memphis, Tennessee, produced IS; 794 (87%) had radiographic CAP and 174 (19%) were HQ. HQ IS yielded pathogenic bacteria more often than LQ (64% vs 44%; P < .01); however, pathogens were isolated at similar rates in HQ IS in patients with and without radiographic CAP (64% vs. 63%; P = .6). Pathogens from study specimens matched an IS pathogen in only 9/42 (21%) patients with radiographic CAP. Median LOS was similar among patients with radiographic CAP regardless of receipt of IS pathogen-concordant antibiotics (3.1 days), non-pathogen-concordant antibiotics (2.7 days), or no antibiotics (3.2 days; P = .5).

CONCLUSIONS

Bacterial pathogens were isolated from most IS cultures regardless of radiographic CAP and quality of IS. IS cultures infrequently corresponded with sterile site cultures. Isolation of pathogens from pediatric IS reflects oropharyngeal carriage and is insufficient to determine bacterial etiology of CAP.

Haemophilus influenzae Serotype a (Hia) Carriage in a Small Alaska Community After a Cluster of Invasive Hia Disease, 2018

BACKGROUND

Between May and July 2018, 4 Haemophilus influenzae serotype a (Hia) infections occurred in a remote Alaska community. We performed a public health response to prevent further illness and understand Hia carriage.

METHODS

We collected oropharyngeal samples community-wide to evaluate baseline carriage. Risk factors were evaluated by interview. We offered prophylactic rifampin to individuals in contact with invasive Hia patients (contacts) and to all children aged <10 years. Oropharyngeal samples were collected again 8 weeks after rifampin distribution. Samples were tested using real-time polymerase chain reaction and culture.

RESULTS

At baseline, 4 of 27 (14.8%) contacts and 7 of 364 (1.9%) noncontacts (P < .01) carried Hia. Contacts aged <10 years were more likely to carry Hia at any timepoint (11/18 [61%]) compared to contacts aged ≥10 years (3/34 [8.8%]), noncontacts aged <10 years (2/139 [1.4%]), and noncontacts ≥10 years (6/276 [2.2%]) (P < .001 for all). Hia carriers were clustered in 9 households (7% of total households). At the household level, carriage was associated with households with ≥1 contact (prevalence ratio [PR], 5.6 [95% confidence interval {CI}, 1.3-21.6]), crowding (PR, 7.7 [95% CI, 1.1-199.5]), and ≥3 tobacco users (PR, 5.0 [95% CI, 1.2-19.6]). Elevated carriage prevalence persisted in contacts compared to noncontacts 8 weeks after rifampin distribution (6/25 [24%] contacts, 2/114 [1.8%] noncontacts; P < .001).

CONCLUSIONS

Hia carriage prevalence was significantly higher among contacts than noncontacts. Rifampin prophylaxis did not result in a reduction of Hia carriage prevalence in this community.

Vitamin C levels in a Central-African mother-infant cohort: Does hypovitaminosis C increase the risk of enteric infections?

In the MITICA (Mother‐to‐Infant TransmIssion of microbiota in Central‐Africa) study, 48 mothers and their 50 infants were followed from delivery to 6 months between December 2017 and June 2019 in Bangui (Central‐African Republic). Blood tests and stool analyses were performed in mothers at delivery, and their offspring at birth, 11 weeks and 25 weeks. Stool cultures were performed in specific growth media for Salmonella, Shigella, E. coli, Campylobacter, Enerobacter, Vibrio cholerae, Citrobacter and Klebsiella, as well as rotavirus, yeasts and parasitological exams. The median vitamin C levels in mothers at delivery were 15.3 μmol/L (inter‐quartile‐range [IQR] 6.2–27.8 μmol/L). In infants, the median vitamin C levels at birth were 35.2 μmol/L (IQR 16.5–63.9 μmol/L). At 11 and 25 weeks, the median vitamin C levels were 41.5 μmol/L (IQR 18.7–71.6 μmol/L) and 18.2 μmol/L (IQR 2.3–46.6 μmol/L), respectively. Hypovitaminosis C was defined as seric vitamin C levels <28 μmol/L and vitamin C deficiency was defined as vitamin C levels <11 μmol/L according to the WHO definition. In mothers, the prevalence of hypovitaminosis‐C and vitamin C deficiency at delivery was 34/45 (75.6%) and 19/45 (42.2%), respectively. In infants, the prevalence of hypovitaminosis‐C and vitamin C deficiency at 6 months was 18/33 (54.6%) and 11/33 (33.3%), respectively. Vitamin C levels in mothers and infants were correlated at birth (Spearman's rho = 0.5; P value = 0.002), and infants had significantly higher levels of vitamin C (median = 35.2 μmol/L; IQR 16.5–63.9 μmol/L), compared to mothers (median = 15.3 μmol/L; IQR 6.2–27.8 μmol/L; P value <0.001). The offspring of vitamin C‐deficient mothers had significantly lower vitamin C levels at delivery (median = 18.7 μmol/L; IQR 13.3–30.7 μmol/L), compared to the offspring of non‐deficient mothers (median = 62.2 μmol/L; IQR 34.6–89.2 μmol/L; P value <0.001). Infants with hypovitaminosis‐C were at significantly higher risk of having a positive stool culture during the first 6 months of life (adjusted OR = 5.3, 95% CI 1.1; 26.1; P value = 0.038).

Airway bacterial carriage and childhood respiratory health: A population-based prospective cohort study

BACKGROUND

Airway bacterial carriage might play a role in respiratory disease. We hypothesize that nasal carriage with Staphylococcus aureus or nasopharyngeal carriage with Haemophilus influenzae, Moraxella catarrhalis, and Streptococcus pneumoniae predisposes individuals to adverse respiratory health.

OBJECTIVE

To examine the association of early-life airway bacterial carriage with respiratory tract infections and vice versa, and of early-life airway bacterial carriage with wheezing, lung function, and asthma in later childhood.

METHODS

We collected upper airway swabs for bacterial culturing for S aureus, H influenzae, M catarrhalis, and H influenzae at six timepoints between the ages of 6 weeks and 6 years among 945 children participating in a population-based prospective cohort study. Information on respiratory tract infections and wheezing until age 6 years, and asthma at age 10 years was obtained by questionnaires. Lung function at age 10 years was measured by spirometry. We tested possible bidirectional associations between airway bacterial carriage and respiratory tract infections by cross-lagged models, and associations of repeatedly measured airway bacterial carriage with wheezing, lung function, and asthma by generalized estimating equations models and regression models.

RESULTS

Cross-lagged modeling showed that early-life airway bacterial carriage was not consistently associated with upper and lower respiratory tract infections or vice versa. Nasopharyngeal carriage with any bacteria in infancy was associated with an increased risk of wheezing (OR [95% CI]: 1.66 [1.31, 2.10]). Airway bacterial carriage was not consistently associated with school-age lung function or asthma.

CONCLUSION

Nasopharyngeal carriage with any bacteria is associated with wheezing, but not respiratory tract infections, asthma, or lung function.

Oral azithromycin given during labour decreases bacterial carriage in the mothers and their offspring: a double-blind randomized trial

Bacterial sepsis remains a leading cause of death among neonates with Staphylococcus aureus, group B streptococcus (GBS) and Streptococcus pneumoniae identified as the most common causative pathogens in Africa. Asymptomatic bacterial colonization is an intermediate step towards sepsis. We conducted a phase III, double-blind, placebo-controlled randomized trial to determine the impact of giving one oral dose of azithromycin to Gambian women in labour on the nasopharyngeal carriage of S. aureus, GBS or S. pneumoniae in the newborn at day 6 postpartum. Study participants were recruited in a health facility in western Gambia. They were followed for 8 weeks and samples were collected during the first 4 weeks. Between April 2013 and April 2014 we recruited 829 women who delivered 843 babies, including 13 stillbirths. Sixteen babies died during the follow-up period. No maternal deaths were observed. No serious adverse events related to the intervention were reported. According to the intent-to-treat analysis, prevalence of nasopharyngeal carriage of the bacteria of interest in the newborns at day 6 was lower in the intervention arm (28.3% versus 65.1% prevalence ratio 0.43; 95% CI 0.36–0.52, p <0.001). At the same time-point, prevalence of any bacteria in the mother was also lower in the azithromycin group (nasopharynx, 9.3% versus 40.0%, p <0.001; breast milk, 7.9% versus 21.6%, p <0.001; and the vaginal tract, 13.2% versus 24.2%, p <0.001). Differences between arms lasted for at least 4 weeks. Oral azithromycin given to women in labour decreased the carriage of bacteria of interest in mothers and newborns and may lower the risk of neonatal sepsis.

Trial registrationClinicalTrials.gov Identifier NCT01800942.

A mathematical model of serotype replacement in pneumococcal carriage following vaccination

A number of childhood vaccination programmes have recently introduced vaccination against Streptococcus pneumoniae, the pneumococcus, a major cause of pneumonia and meningitis. The pneumococcal conjugate vaccines (PCVs) that are currently in use only protect against some serotypes of the bacterium, and there is now strong evidence that those serotypes not included in the vaccine increase in prevalence among most vaccinated populations. We present a mathematical model for the dynamics of nasopharyngeal carriage of S. pneumoniae that allows for carriage with multiple serotypes. The model is used to predict the prevalence of vaccine type (VT) and non-VT (NVT) serotypes following the introduction of PCV. Parameter estimates for the model are obtained by maximum likelihood using pre-vaccination data from The Gambia. The model predicts that low (1, 6A and 9V) and medium (4, 5, 7F, 14, 18C, 19A and 19F) prevalence serotypes can be eliminated through vaccination, but that the overall prevalence of carriage will be reduced only slightly because of an increase in the prevalence of NVT serotypes. Serotype replacement will be sequential, with high and medium prevalence NVT serotypes dominating initially, followed by an increase of serotypes of low prevalence. We examine the impact of a hypothetical vaccine that provides partial protection against all serotypes, and find that this reduces overall carriage, but is unable to eliminate low or medium prevalence serotypes.