Epidemiology of infections due to extended-spectrum Beta-lactamase-producing bacteria in a pediatric intensive care unit

Carriage and antimicrobial susceptibility patterns of rectal ESBL E. coli in surgical patients at the University Teaching Hospitals in Lusaka, Zambia

Background

Surgical site infections (SSIs) are on the rise and are a global concern as they complicate the recovery of patients postoperatively. Bacterial colonization of the patient's skin and alimentary tract are known to be major contributing sources to SSIs. However, Zambia lacks data relating to carriage rates of antibiotic-resistant rectal Escherichia coli among surgical patients.

Methods

This was a cross-sectional study aimed at determining the preoperative (preop) and postoperative (postop) carriage and antimicrobial susceptibility patterns of rectal ESBL-producing E. coli (ESBL-Ec) in elective surgery patients at the highest tertiary hospital in Lusaka, Zambia. Phenotypic methods were used in the identification of E. coli. Antibiotic susceptibility patterns and identification of ESBL-Ec was determined by Kirby-Bauer disc diffusion.

Results

A total of 120 study participants were recruited, of which 75 were followed up at least 72 h after surgery. From 195 rectal swabs cultured, 177 (90.8%) were positive for E. coli, of which 53 (29.9%) were ESBL-Ec, with a significantly (P < 0.0001) higher proportion in postop (47.9%) than preop (17.3%) participants. Overall, ESBL-Ec isolates showed higher resistance in postop than preop to cefotaxime (100% versus 88.9%, respectively), ampicillin (100% versus 94.4%), ciprofloxacin (88.3% versus 83.3%), amoxicillin/clavulanic acid (80% versus 66.7%) and cefepime (80% versus 77.8%). MDR ESBL-Ec strains were more frequent in postop than in preop participants (91.4% versus 88.9%).

Conclusions

The study showed a significantly higher rate of antimicrobial-resistant rectal E. coli in postop than preop participants. There is a need to ascertain the source of the resistance and to institute robust infection control measures, preop screening of surgical patients for ESBL-Ec, and to raise awareness on prudent use of antibiotics.

Challenges of Antibiotic Stewardship in the Pediatric and Neonatal Intensive Care Units

The goals of antimicrobial stewardship programs (ASPs) are to optimize antimicrobial prescribing habits in order to improve patient outcomes, reduce antimicrobial resistance, and reduce hospital costs. Multiple society-endorsed guidelines and government policies reinforce the importance of ASP implementation. Effective antimicrobial stewardship can impact unique patients, hospitals, and societal antibiotic-resistance burden. The role and subsequent success of these programs has largely been reported in the adult population. Pediatric and neonatal intensive care units present unique challenges for traditional antimicrobial stewardship approaches. The purpose of this review article is to explore the challenges of appropriate antibiotic use in the pediatric and neonatal intensive care units and to summarize strategies ASPs can use to overcome these challenges. These problems include non-specific disease presentations, limited evidence for definitive treatment durations in many pediatric infections, fewer pediatric-trained infectious disease physicians, and applicability of intensive laboratory obtainment, collection, and interpretation. Additionally, many ASP implementation studies evaluating the efficacy of ASPs exclude the PICU and NICU. Areas of focus for pediatric ASPs should likely include appropriate antibiotic initiation, appropriate antibiotic duration, and appropriate antibiotic de-escalation.

Optimizing the Use of Antibiotic Agents in the Pediatric Intensive Care Unit: A Narrative Review

Antibiotics are one of the most prescribed drug classes in the pediatric intensive care unit, yet the incidence of inappropriate antibiotic prescribing remains high in critically ill children. Optimizing the use of antibiotics in this population is imperative to guarantee adequate treatment, avoid toxicity and the occurrence of antibiotic resistance, both on a patient level and on a population level. Antibiotic stewardship encompasses all initiatives to promote responsible antibiotic usage and the PICU represents a major target environment for antibiotic stewardship programs. This narrative review provides a summary of the available knowledge on the optimal selection, duration, dosage, and route of administration of antibiotic treatment in critically ill children. Overall, more scientific evidence on how to optimize antibiotic treatment is warranted in this population. We also give our personal expert opinion on research priorities.

Molecular characterization of invasive Enterobacteriaceae from pediatric patients in Central and Northwestern Nigeria

Background

Bacteremia is a leading cause of mortality in developing countries, however, etiologic evaluation is infrequent and empiric antibiotic use not evidence-based. Here, we evaluated the patterns of ESBL resistance in children enrolled into a surveillance study for community acquired bacteremic syndromes across health facilities in Central and Northwestern Nigeria.

Method

Blood culture was performed for children aged less than 5 years suspected of having sepsis from Sept 2008-Dec 2016. Blood was incubated using the BACTEC^00AE system and Enterobacteriacea identified to the species level using Analytical Profile Index (API20E^®). Antibiotic susceptibility profile was determined by the disc diffusion method. Real time PCR was used to characterize genes responsible for ESBL production.

Result

Of 21,000 children screened from Sept 2008-Dec 2016, 2,625(12.5%) were culture-positive. A total of 413 Enterobacteriaceae available for analysis were screened for ESBL. ESBL production was detected in 160 Enterobacteriaceae, high resistance rates were observed among ESBL-positive isolates for Ceftriaxone (92.3%), Aztreonam (96.8%), Cefpodoxime (96.3%), Cefotaxime (98.8%) and Trimethoprim/sulfamethoxazole (90%), while 87.5%, 90.7%, and 91.9% of the isolates were susceptible to Imipenem, Amikacin and Meropenem respectively. Frequently detected resistance genes were blaTEM—83.8% (134/160), and, blaCTX-M 83.1% (133/160) followed by blaSHVgenes 66.3% (106/160). Co-existence of blaCTX-M, blaTEM and blaSHV was seen in 94/160 (58.8%), blaCTX-M and blaTEM in 118/160 (73.8%), blaTEM and blaSHV in 97/160 (60.6%) and blaCTX-M and blaSHV in 100/160 (62.5%) of isolates tested.

Conclusion

Our results indicate a high prevalence of bacteremia from ESBL Enterobacteriaceae in this population of children. These are resistant to commonly used antibiotics and careful choice of antibiotic treatment options is critical. Further studies to evaluate transmission dynamics of resistance genes could help in the reduction of ESBL resistance in these settings.

Preliminary survey of extended-spectrum β-lactamases (ESBLs) in nosocomial uropathogen Klebsiella pneumoniae in north-central Iran

Infections caused by extended-spectrum β-lactamases (ESBLs) producing bacteria, including Klebsiella pneumoniae have increasingly subjected to therapeutic limitations and patients with these infections are at high risk for treatment failure, long hospital stays, high health care costs, and high mortality. The aim of this study was to screen the prevalence of the bla TEM,bla CTX-M and bla SHV ESBL genes in K. pneumoniae strains isolated from nosocomial urinary tract infections (UTIs). During the March 2016 to December 2017, one hundred isolates of K. pneumoniae were collected from urine specimens of patients suffering from nosocomial UTI referred to Khatam Al-Anbia hospital in Shahrud, north-central Iran. All isolates were identified by standard bacteriological tests. The pattern of antibiotic susceptibility was determined according to the CLSI guidelines. The presence of the ESBLs was investigated using the double-disc synergy test (DDST). Polymerase chain reaction technique was used to detect the bla TEM, bla CTX-M and bla SHV genes in DDST positive isolates. Most isolates showed remarkable resistance to tested antibiotics with highest rate against nitrofurantoin (75%) and trimethoprim/sulfamethoxazole (65%). The imipenem was the most effective antibiotic against K. pneumoniae isolates. ESBL phenotype was detected in 50 (50%) of isolates. The prevalence of bla TEM, bla CTX-M and bla SHV genes among 50 ESBLs-positive isolates was 25 (50%), 15 (30%) and 35 (70%) respectively. The bla TEM and bla SHV genes were seen in 25 isolates (50%) simultaneously. The findings of this study indicated the 50% frequency rate of ESBL-producing K. pneumoniae in our geographic region. Since the treatment of infections caused by this bacterium is associated with many limitations, this high prevalence is a warning sign to adopt new control policies to prevent further spread of this microorganism.

Adherent/invasive Escherichia coli (AIEC) isolates from asymptomatic people: new E. coli ST131 O25:H4/H30-Rx virotypes

BACKGROUND

The widespread Escherichia coli clone ST131 implicated in multidrug-resistant infections has been recently reported, the majority belonging to O25:H4 serotype and classified into five main virotypes in accordance with the virulence genes carried.

METHODS

Pathogenicity Islands I and II (PAI-I and PAI-II) were determined using conventional PCR protocols from a set of four E. coli CTXR ST131 O25:H4/H30-Rx strains collected from healthy donors' stool. The virulence genes patterns were also analyzed and compared them with the virotypes reported previously; then adherence, invasion, macrophage survival and biofilm formation assays were evaluated and AIEC pathotype genetic determinants were investigated.

FINDINGS

Non-reported virulence patterns were found in our isolates, two of them carried satA, papA, papGII genes and the two-remaining isolates carried cnfI, iroN, satA, papA, papGII genes, and none of them belonged to classical ST131 virotypes, suggesting an endemic distribution of virulence genes and two new virotypes. The presence of PAI-I and PAI-II of Uropathogenic E. coli was determined in three of the four strains, furthermore adherence and invasion assays demonstrated higher degrees of attachment/invasion compared with the control strains. We also amplified intI1, insA and insB genes in all four samples.

INTERPRETATION

The results indicate that these strains own non-reported virotypes suggesting endemic distribution of virulence genes, our four strains also belong to an AIEC pathotype, being this the first report of AIEC in México and the association of AIEC with healthy donors.

Restoration of T Cell function in multi-drug resistant bacterial sepsis after interleukin-7, anti-PD-L1, and OX-40 administration

BACKGROUND

Multidrug resistant (MDR) bacterial pathogens are a serious problem of increasing importance facing the medical community. MDR bacteria typically infect the most immunologically vulnerable: patients in intensive care units, patients with extensive comorbidities, oncology patients, hemodialysis patients, and other immune suppressed individuals are likely to fall victim to these pathogens. One promising novel approach to treatment of MDR bacteria is immuno-adjuvant therapy to boost patient immunity. Success with this strategy would have the major benefit of providing protection against a number of MDR pathogens.

OBJECTIVES

This study had two main objectives. First, immunophenotyping of peripheral blood mononuclear cells from patients with sepsis associated with MDR bacteria was performed to examine for findings indicative of immunosuppression. Second, the ability of three immuno-adjuvants with distinct mechanisms of action to reverse CD4 and CD8 T cell dysfunction, a pathophysiological hallmark of sepsis, was evaluated.

RESULTS

Septic patients with MDR bacteria had increased expression of the inhibitory receptor PD-1 and its ligand PD-L1 and decreased monocyte HLA-DR expression compared to non-septic patients. All three immuno-adjuvants, IL-7, anti-PD-L1, and OX-40L, increased T cell production of IFN-γ in a subset of septic patients with MDR bacteria: IL-7 was most efficacious. There was a strong trend toward increased mortality in patients whose T cells failed to increase IFN-γ production in response to the three treatments.

CONCLUSION

Immuno-adjuvant therapy reversed T cell dysfunction, a key pathophysiological mechanism in septic patients with MDR bacteria.

Outbreak epidemiologically linked with a composite product of beef, mechanically separated chicken and textured vegetable protein contaminated with multiple serotypes of Salmonella enterica including multidrug-resistant Infantis, California 2016

A salmonellosis outbreak occurred at a California prison in April and May 2016. In a cohort study of 371 inmates, persons who consumed dishes from the prison kitchen made from ground meat had a higher attack rate (15%) than those who did not (4%) (risk ratio 3.4, 95% CI 1.1–10.6). The ground meat product was composed exclusively of beef, mechanically separated chicken (MSC) and textured vegetable protein; eight of eight lots of the product collected from the prison and processing facility were contaminated with Salmonella enterica of eight serotypes and 17 distinct PFGE patterns, including multidrug-resistant S. Infantis. Either the MSC or the beef could have been the source of the particular strains of S. enterica isolated from patients or the product. The microbiological evidence is most consistent with MSC as the source of the high levels of S. enterica in the epidemiologically linked meat product. Our findings contribute to the growing body of evidence about the hazard posed by the use of products containing raw mechanically separated poultry in kitchens in institutions.

A comparison of blood stream infections with extended spectrum beta-lactamase-producing and non-producing Klebsiella pneumoniae in pediatric patients

Background

Rapid development and global spread of multidrug resistant Klebsiella pneumonia (K. pneumoniae) as a major cause of nosocomial infections is really remarkable. The aim of this study was to explore risk factors for health care associated blood stream infections (BSI) caused by ESBL-producing K. pneumoniae in children and analyze clinical outcomes.

Methods

A retrospective review of patients younger than 18 years-old with blood stream infection caused by K. pneumoniae was performed. Patients with ESBL-producing K. pneumoniae isolates were compared with ESBL-non-producing isolates in terms of risk factors, outcome and mortality.

Results

Among 111 K. pneumoniae isolates 62% (n = 69) were ESBL –producing K. pneumoniae. The median total length of hospitalization and median length of stay in hospital before infection was significantly higher in patients with ESBL-producing isolates than ESBL-non-producing. Use of combined antimicrobial treatment was significantly different between ESBL-producing and ESBL-non-producing groups, 75.4% and 24.6%, respectively (p = 0.001). Previous aminoglycoside use was higher in cases with ESBL –producing isolates (p = 0.001). Logistic regression analysis showed a significant correlation between mortality and use of combined antibiotics (OR 4.22; p = 0.01).

Conclusion

ESBL production in K. pneumoniae isolates has a significant impact on clinical course of BSIs. Total length of hospitalization, length of hospital stay before infection, prior combined antibiotic use and use of aminoglycosides were significant risk factors for development of ESBL-producing K. pneumoniae related BSI.

Improved Accuracy of Cefepime Susceptibility Testing for Extended-Spectrum-Beta-Lactamase-Producing Enterobacteriaceae with an On-Demand Digital Dispensing Method

Extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae generally cannot be treated with penicillins and cephalosporins. However, some later-generation cephalosporins, including cefepime, are poorly hydrolyzed by specific ESBL enzymes, and certain strains demonstrate in vitro susceptibility to these agents, potentially affording additional treatment opportunities. Moreover, the ability to adjust both the dose and dosing interval of beta-lactam agents allows the treatment of strains with elevated MICs that were formerly classified in the intermediate range. The ability to treat strains with elevated cefepime MICs is codified in new susceptible dose-dependent (SDD) breakpoints promulgated by the Clinical and Laboratory Standards Institute. In the interest of validating and implementing new cefepime SDD criteria, we evaluated the performances of Vitek 2, disk diffusion, and a MicroScan panel compared to that of reference broth microdilution (BMD) during the testing of 64 strains enriched for presumptive ESBL phenotype (based on nonsusceptibility to ceftriaxone). Surprisingly, categorical agreement with BMD was only 47.6%, 57.1%, and 44.6% for the three methods, respectively. Given these findings, we tested the performance of the HP D300 inkjet-assisted broth microdilution digital dispensing method (DDM), which was previously described by our group as an at-will testing alternative. In contrast to commercial methods, DDM results correlated well with the reference method, with 86% categorical agreement, 91.1% evaluable essential agreement, and no major or very major errors. The reproducibility and accuracy of MIC determinations were statistically equivalent to BMD. Our results provide support for the use of the DDM as a BMD equivalent methodology that will enable hospital-based clinical laboratories to support cefepime MIC-based dosing strategies.

Extended-spectrum β-lactamase-producing Enterobacteriaceae in cell phones of health care workers from Peruvian pediatric and neonatal intensive care units

BACKGROUND

Health care workers (HCWs) use their mobile phones during working hours or medical care. There is evidence that the instruments are colonized with pathogenic microorganisms. Here, we describe levels of Enterobacteriaceae contamination (EC) in cell phones and the risk factors associated with EC in Peruvian intensive care units (ICUs).

METHODS

This was a 5-month cohort study among 114 HCWs of 3 pediatric and 2 neonatology ICUs from 3 Peruvian hospitals. A baseline survey collected data on risk factors associated with EC. Swabs were collected from HCWs' phones every other week.

RESULTS

Three-quarters of HCWs never decontaminated their phones, and 47% reported using the phones in the ICU >5 times while working. EC was frequent across samplings and sites and was substantially higher in subjects with longer follow-up. Potential risk factors identified did not have strong associations with positive samples (relative risk, 0.7-1.5), regardless of significance. Half of the phones were colonized with an Enterobacteriaceae at least once during the 4 samplings attained on average during the study period. Half of the isolates were multidrug resistant (MDR), and 33% were extended-spectrum β-lactamase producers.

CONCLUSIONS

EC on HCWs' phones was frequent and apparently randomly distributed through the hospitals without clear clustering or strongly associated risk factors for having a positive sample. Based on the level of EC, phones may be considered as potential bacterial reservoirs of MDR and ESBL bacteria.

Prevalence of Plasmid-Mediated Quinolone Resistance Genes among Extended-Spectrum β -Lactamase-Producing Klebsiella pneumoniae Human Isolates in Iran

The purpose of this study was to determine the prevalence and molecular characterization of plasmid-mediated quinolone resistance (PMQR) genes (qnrA, qnrB, qnrS, aac(6′)-Ib-cr, and qepA) among ESBL-producing Klebsiella pneumoniae isolates in Kashan, Iran. A total of 185 K. pneumoniae isolates were tested for quinolone resistance and ESBL-producing using the disk diffusion method and double disk synergy (DDST) confirmatory test. ESBL-producing strains were further evaluated for the bla_CTX-M genes. The PCR method was used to show presence of plasmid-mediated quinolone resistance genes and the purified PCR products were sequenced. Eighty-seven ESBL-producing strains were identified by DDST confirmatory test and majority (70, 80.5%) of which carried bla_CTX-M genes including CTX-M-1 (60%), CTX-M-2 (42.9%), and CTX-M-9 (34.3%). Seventy-seven ESBL-producing K. pneumoniae isolates harbored PMQR genes, which mostly consisted of aac(6′)-Ib-cr (70.1%) and qnrB (46.0%), followed by qnrS (5.7%). Among the 77 PMQR-positive isolates, 27 (35.1%) and 1 (1.3%) carried 2 and 3 different PMQR genes, respectively. However, qnrA and qepA were not found in any isolate. Our results highlight high ESBL occurrence with CTX-M type and high frequency of plasmid-mediated quinolone resistance genes among ESBL-producing K. pneumoniae isolates in Kashan.

Extended-Spectrum Beta-Lactamase Bacteria From Urine Isolates in Children

OBJECTIVES

Multidrug-resistant Gram-negative bacteria, including extended-spectrum beta-lactamase (ESBL)-producing organisms, are a growing problem. The primary objective of this study was to describe the proportion of children with ESBL-producing urinary isolates at a tertiary medical center as well as these organisms' susceptibility patterns. The secondary objective was to identify the risk factors for acquiring ESBL urinary pathogens.

METHODS

This retrospective study evaluated a cohort of children with ESBL urinary isolates, admitted to a tertiary children's hospital during a 6-year period. The proportion of patients with an ESBL-producing urinary isolate among all patients who grew a Gram-negative isolate is described together with the organism's susceptibility pattern. Patients with non-ESBL Gram-negative urinary organisms were used as a control group for identifying patient risk factors for ESBL.

RESULTS

A total of 7.8% (29 of 370) of patients in our cohort grew Gram-negative urinary isolates with an ESBL strain. Most of the ESBL organisms isolated were sensitive to carbapenems (100% of ESBL organisms susceptible to ertapenem and 93.8% susceptible to meropenem) and amikacin (92.3% of ESBL organisms susceptible). Patients with longer hospitalization, recent antibiotic use, and recent intensive care unit admission were found to be at increased risk for ESBL organisms in the urine.

CONCLUSIONS

When selecting empiric antibiotic therapy for suspected urinary tract infection in children, it may be prudent to consider the risk factors identified for acquiring an ESBL urinary pathogen.