Progressive increase in antimicrobial resistance among invasive isolates of Haemophilus influenzae obtained from children admitted to a hospital in Kilifi, Kenya, from 1994 to 2002

Etiology of Bacterial Meningitis Among Children <5 Years Old in Côte d'Ivoire: Findings of Hospital-based Surveillance Before and After Pneumococcal Conjugate Vaccine Introduction

Background

Bacterial meningitis remains a major disease affecting children in Côte d’Ivoire. Thus, with support from the World Health Organization (WHO), Côte d’Ivoire has implemented pediatric bacterial meningitis (PBM) surveillance at 2 sentinel hospitals in Abidjan, targeting the main causes of PBM: Streptococcus pneumoniae (pneumococcus), Haemophilus influenzae, and Neisseria meningitidis (meningococcus). Herein we describe the epidemiological characteristics of PBM observed in Côte d’Ivoire during 2010–2016.

Methods

Cerebrospinal fluid (CSF) was collected from children aged <5 years admitted to the Abobo General Hospital or University Hospital Center Yopougon with suspected meningitis. Microbiology and polymerase chain reaction (PCR) techniques were used to detect the presence of pathogens in CSF. Where possible, serotyping/grouping was performed to determine the specific causative agents.

Results

Overall, 2762 cases of suspected meningitis were reported, with CSF from 39.2% (1083/2762) of patients analyzed at the WHO regional reference laboratory in The Gambia. In total, 82 (3.0% [82/2762]) CSF samples were positive for bacterial meningitis. Pneumococcus was the main pathogen responsible for PBM, accounting for 69.5% (52/82) of positive cases. Pneumococcal conjugate vaccine serotypes 5, 18C, 19F, and 6A/B were identified post–vaccine introduction. Emergence of H. influenzae nontypeable meningitis was observed after H. influenzae type b vaccine introduction.

Conclusions

Despite widespread use and high coverage of conjugate vaccines, pneumococcal vaccine serotypes and H. influenzae type b remain associated with bacterial meningitis among children aged <5 years in Côte d’Ivoire. This reinforces the need for enhanced surveillance for vaccine-preventable diseases to determine the prevalence of bacterial meningitis and vaccine impact across the country.

The expanding role of co-trimoxazole in developing countries

Co-trimoxazole is an inexpensive, broad-spectrum antimicrobial drug that is widely used in developing countries. Before antiretroviral therapy (ART) scale-up, co-trimoxazole prophylaxis reduced morbidity and mortality in adults and children with HIV by preventing bacterial infections, diarrhoea, malaria, and Pneumocystis jirovecii pneumonia, despite high levels of microbial resistance. Co-trimoxazole prophylaxis reduces early mortality by 58% (95% CI 39-71) in adults starting ART. Co-trimoxazole provides ongoing protection against malaria and non-malaria infections after immune reconstitution in ART-treated individuals in sub-Saharan Africa, leading to a change in WHO guidelines, which now recommend long-term co-trimoxazole prophylaxis for adults and children in settings with a high prevalence of malaria or severe bacterial infections. Co-trimoxazole prophylaxis is recommended for HIV-exposed infants from age 4-6 weeks; however, the risks and benefits of co-trimoxazole during infancy are unclear. Co-trimoxazole prophylaxis reduces anaemia and improves growth in children with HIV, possibly by reducing inflammation, either through direct immunomodulatory activity or through effects on the intestinal microbiota leading to reduced microbial translocation. Ongoing trials are now assessing the ability of adjunctive co-trimoxazole to reduce mortality in children after severe anaemia or severe acute malnutrition. In this Review, we discuss the mechanisms of action, benefits and risks, and clinical trials of co-trimoxazole in developing countries.

Nasopharyngeal carriage and antimicrobial susceptibility of Haemophilus influenzae among children younger than 5 years of age in Beijing, China

Background

Haemophilus influenzae is one of the main pathogens that cause community-acquired respiratory infections in children. Our previous study showed that H. influenzae is the second most common pathogen causing pneumonia and accounts for 30–50% of bacterial meningitis among Chinese children. H. influenzae carriage in children and its resistance to commonly used antimicrobials varies widely both geographically and over time.

Results

Surveys of the nasopharyngeal carriage of H. influenzae in children younger than 5 years of age with acute respiratory tract infection (ARI) were conducted in Beijing Children’s Hospital, China in 2000, 2002, 2010, and 2012. The overall annual carriage rates of H. influenzae among children younger than 5 years of age with ARI were 35.5%, 20.6%, 14.4%, and 18.7%, and the percentages of H. influenzae isolates producing β-lactamase were 4%, 13%, 27.1%, and 31%, respectively. The percentages of susceptibility to ampicillin progressively decreased from 96% (2000) to 87% (2002) to 63% (2010) to 61% (2012). All of the ampicillin-resistant isolates were found to be beta-lactamase producers. The susceptibility to tetracycline increased from 54% (2000) to 60% (2002) to 91.5% (2010) to 94.5% (2012). No statistically significant differences were observed in the susceptibility to cefaclor, cefuroxime, sulfamethoxazole, and chloramphenicol. Amoxicillin/clavulanic acid and ceftriaxone were the most effective antimicrobials for the isolates of H. influenzae across the 10-year period.

Conclusions

This report on the H. influenzae carriage rates in children and the susceptibility of these bacteria to commonly used antibiotics showed that H. influenzae carriage decreased from 2000 to 2012. Additionally, the percentage of β-lactamase-producing isolates increased while their susceptibility to ampicillin progressively decreased during this time. These results indicate that the appropriate empirical antimicrobial therapy should be changed for pediatric patients in China.

Antimicrobial drug resistance among clinically relevant bacterial isolates in sub-Saharan Africa: a systematic review

BACKGROUND

Little is known about the prevalence of antimicrobial resistance (AMR) amongst bacterial pathogens in sub-Saharan Africa (sSA), despite calls for continent-wide surveillance to inform empirical treatment guidelines.

METHODS

We searched PubMed and additional databases for susceptibility data of key pathogens for surveillance, published between 1990 and 2013. Extracted data were standardized to a prevalence of resistance in populations of isolates and reported by clinical syndrome, microorganism, relevant antimicrobial drugs and region.

RESULTS

We identified 2005 publications, of which 190 were analysed. Studies predominantly originated from east sSA (61%), were hospital based (60%), were from an urban setting (73%) and reported on isolates from patients with a febrile illness (42%). Quality procedures for susceptibility testing were described in <50% of studies. Median prevalence (MP) of resistance to chloramphenicol in Enterobacteriaceae, isolated from patients with a febrile illness, ranged between 31.0% and 94.2%, whilst MP of resistance to third-generation cephalosporins ranged between 0.0% and 46.5%. MP of resistance to nalidixic acid in Salmonella enterica Typhi ranged between 15.4% and 43.2%. The limited number of studies providing prevalence data on AMR in Gram-positive pathogens or in pathogens isolated from patients with a respiratory tract infection, meningitis, urinary tract infection or hospital-acquired infection suggested high prevalence of resistance to chloramphenicol, trimethoprim/sulfamethoxazole and tetracycline and low prevalence to third-generation cephalosporins and fluoroquinolones.

CONCLUSIONS

Our results indicate high prevalence of AMR in clinical bacterial isolates to antimicrobial drugs commonly used in sSA. Enhanced approaches for AMR surveillance are needed to support empirical therapy in sSA.

Current concepts in the treatment of bacterial meningitis beyond the neonatal period

The epidemiology and treatment approach to bacterial meningitis has changed dramatically since the advent of antimicrobial therapy. New vaccines against meningeal pathogens have been implemented into national immunization programs successfully around the world. Antibiotic resistance has had a considerable impact on the efficacy of several therapeutic agents. In this review, the authors will discuss the principles of antibiotic chemotherapy, focusing on new agents for the treatment of penicillin-resistant pneumococci and adjunctive treatments to reduce the inflammatory response to bacterial infection of the meninges.

Antibiotic resistance and molecular epidemiology of the beta-lactamase-producing Haemophilus influenzae isolated in Chongqing, China

This study aimed to determine the antibiotic resistance and molecular epidemiology of Haemophilus influenzae isolated from children with acute respiratory infection in Chongqing, China. To this end, 1967 H. influenzae isolates from 2006 to 2009 were analysed regarding β-lactamase production and antibiotic resistance. Ninety-nine β-lactamase-producing H. influenzae isolates from 2010 were analysed for antibiotic resistance and promoter regions of bla(TEM) (-1) . β-lactamase production was found in 35.8% (705/1967) of the strains. All ninety-nine β-lactamase-producing strains from 2010 were of the TEM-1 type as determined by PCR but did not produce the predicted 1075 bp product. According to PCR-SSCP and DNA sequencing, the promoter regions of bla(TEM) (-1) were categorized into 6 genotypes as SSCP1 (Pdel), SSCP2 (Pa/Pb), SSCP3 (P4), SSCP4 (Prpt.b), SSCP5 (2Prpt) and SSCP6 (P3.b). The Pdel, Pa/Pb and Prpt.b were common promoters of bla(TEM) (-1) for H. influenzae isolated from children in Chongqing. Strains with Prpt.b were more resistant to ampicillin (AMP) than strains with Pdel, Pa/Pb and P4 (p < 0.05). Therefore, bla(TEM-1) β-lactamase is the main mechanism for resistance of H. influenzae to ampicillin in Chongqing. Furthermore, the Prpt.b promoters may be related to the high resistance of H. influenzae to AMP.

Antimicrobial drug resistance trends of bacteremia isolates in a rural hospital in southern Mozambique

Antibiotic resistance in Africa is increasing but insufficiently recognized as a public health problem. However, there are scarce data for antimicrobial resistance trends among bloodstream isolates in sub-Saharan Africa. Antimicrobial drug resistance trends among bacteria isolated from blood of children < 15 years of age admitted to the Manhiça District Hospital in Mozambique during May 2001-April 2006 were monitored by disk diffusion. We documented a linear trend of increasing resistance throughout the study period to chloramphenicol among isolates of Non-typhi Salmonella (P < 0.001), Escherichia coli (P = 0.002), Staphylococcus aureus (P < 0.001), and Haemophilus influenzae (P < 0.001). Increasing resistance to ampicillin was also observed for H. influenzae isolates (P < 0.001). We report trends of increasing resistance among the most frequent etiologies of bacteremia to the most commonly used antibiotics for empirical therapy in this community. Quinolones and third-generation cephalosporines may be needed in the short term to manage community-acquired infections.

WHO guidelines for antimicrobial treatment in children admitted to hospital in an area of intense Plasmodium falciparum transmission: prospective study

OBJECTIVES

To assess the performance of WHO's "Guidelines for care at the first-referral level in developing countries" in an area of intense malaria transmission and identify bacterial infections in children with and without malaria.

DESIGN

Prospective study.

SETTING

District hospital in Muheza, northeast Tanzania.

PARTICIPANTS

Children aged 2 months to 13 years admitted to hospital for febrile illness.

MAIN OUTCOME MEASURES

Sensitivity and specificity of WHO guidelines in diagnosing invasive bacterial disease; susceptibility of isolated organisms to recommended antimicrobials.

RESULTS

Over one year, 3639 children were enrolled and 184 (5.1%) died; 2195 (60.3%) were blood slide positive for Plasmodium falciparum, 341 (9.4%) had invasive bacterial disease, and 142 (3.9%) were seropositive for HIV. The prevalence of invasive bacterial disease was lower in slide positive children (100/2195, 4.6%) than in slide negative children (241/1444, 16.7%). Non-typhi Salmonella was the most frequently isolated organism (52/100 (52%) of organisms in slide positive children and 108/241 (45%) in slide negative children). Mortality among children with invasive bacterial disease was significantly higher (58/341, 17%) than in children without invasive bacterial disease (126/3298, 3.8%) (P<0.001), and this was true regardless of the presence of P falciparum parasitaemia. The sensitivity and specificity of WHO criteria in identifying invasive bacterial disease in slide positive children were 60.0% (95% confidence interval 58.0% to 62.1%) and 53.5% (51.4% to 55.6%), compared with 70.5% (68.2% to 72.9%) and 48.1% (45.6% to 50.7%) in slide negative children. In children with WHO criteria for invasive bacterial disease, only 99/211(47%) of isolated organisms were susceptible to the first recommended antimicrobial agent.

CONCLUSIONS

In an area exposed to high transmission of malaria, current WHO guidelines failed to identify almost a third of children with invasive bacterial disease, and more than half of the organisms isolated were not susceptible to currently recommended antimicrobials. Improved diagnosis and treatment of invasive bacterial disease are needed to reduce childhood mortality.

Antimicrobial resistance of bacterial agents of the upper respiratory tract of school children in Buea, Cameroon

The study was aimed at determining bacterial agents of the upper respiratory tract and the susceptibility patterns of isolates to antibiotics. In total, 200 throat swabs were obtained from students attending different boarding schools within the Buea Municipality and screened to obtain the prevalence of respiratory pathogens and to understand the antibiotic susceptibility patterns of isolates using standard microbiological procedure and the disc-diffusion test. Of the 200 samples screened, 112 (56%) had positive cultures with the dominant bacterial pathogens being Haemophilus influenzae (20%), followed by Streptococcus pneumoniae (15%), Klebsiella pneumoniae (11%), and Staphylococcus aureus (10%). Although 56% of the isolates were recovered from females compared to 44% from males, the difference was not statistically significant (p>0.05). Sixty-seven percent of the pathogens were isolated from the age-group of 10-13 years, 19.6% from the age-group of 14-17 years, and 12.5% from the age-group of 18-21 years. Antibiotic susceptibility testing revealed that gentamicin (92%) and cefuroxime (88.4%) were the most effective antibiotics against the isolates. Generally, susceptibility ranged from 0% to 92% depending on the antibiotic and the species of microorganism. Penicillin had the highest (100%) resistance to all the isolates. The findings revealed that students living in boarding schools in the Buea Municipality were at risk of acquiring upper respiratory tract infections from their peers since the upper respiratory tract of more than 50% of the students was colonized with respiratory pathogens. Although multidrug-resistant strains of organisms were identified, gentamicin and cefuroxime are recommended as the first-line antibiotics of choice against the pathogens. There is, therefore, a need for surveillance of nasopharyngeal carriage of resistant strains of these organisms, especially H. influenzae in unhealthy school children since the vaccine is yet to be introduced in Cameroon. The findings have clinical and epidemiological significance.

Antimicrobial susceptibility of Haemophilus influenzae strains and antibiotics usage patterns in pediatric outpatients: results from a children's hospital in China (2000-2004)

OBJECTIVE

To investigate the nasopharyngeal carriage and antimicrobial susceptibility of H. influenzae among children younger than 5 years old and to assess antibiotics usage patterns in the outpatient department of Beijing Children's Hospital from 2000 to 2004.

MATERIALS AND METHODS

From 2000 to 2004, At least 100 strains of H. influenzae were isolated from the pediatric patients who were younger than 5 years and who presented with symptoms of acute upper respiratory tract infections during February to May in each of the study years. Antimicrobial susceptibilities were determined; and antibiotics usage was expressed as defined daily dose (DDD)/100 patient days.

RESULTS

The overall nasopharyngeal carriage rate of H. influenzae is 26.3% (562/2,137) in children younger than 5 years old with acute upper respiratory tract infection. The percentage of ampicillin-resistant isolates ranges from 4.0% (4/100) to 14.3% (17/119) from 2000 to 2004. All the ampicillin-resistant isolates are beta-lactamase producers. More than 80% of the isolates are susceptible to amoxicillin, cefaclor, and chloramphenicol; whereas, almost all (99-100%) of the isolates are sensitive to amoxicillin/clavulanic acid, ceftriaxone, and cefuroxime. For antibiotics utilization, macrolides are the predominantly used antibiotics, followed by cephalosporins and penicillins among pediatric patients in the outpatient department during the study period.

CONCLUSION

All amoxicillin-resistant isolates of H. influenzae are producing beta-Lactamase; and the rates of amoxicillin-resistant isolates are increasing over time. Amoxicillin/clavulanic acid and cephalosporins are highly sensitive to H. influenzae isolated from Chinese pediatric patients. Macrolides are the most used antibiotics in the outpatient department during the study period.

Direct detection of the multidrug resistance genome of Haemophilus influenzae in cerebrospinal fluid of children: implications for treatment of meningitis

BACKGROUND

Multidrug resistance (MDR), specifically to ampicillin and chloramphenicol, has complicated the treatment of Haemophilus influenzae type b (Hib) meningitis. This is worsened by use of prior antibiotics, which limits identification of the causative agent by culture and increases reliance on antigen detection.

OBJECTIVE

We aimed to develop a PCR assay for detecting the family of Haemophilus integrating and conjugative elements (ICEs) represented by ICEHin1056 among antibiotic resistant Hib, and then apply this directly to CSF to diagnose Hib meningitis and predict organism susceptibility, irrespective of culture results.

STUDY DESIGN

Primers specific for orf 51 of ICEHin1056 were designed and multiplexed with Bex primers, specific for H. influenzae, and tested on culture positive and negative cases.

RESULTS

Of 73 Hib isolates, orf 51 PCR amplicons, predicting the presence of ICEs, were found in all 33 MDR isolates while only in 1 of 33 sensitive strains. The remaining 7 ampicillin susceptible, chloramphenicol and tetracycline resistant strains did not produce a PCR product to orf 51. PCR amplification from CSF specimens of these culture positive cases produced identical results with 100% and 97% positive and negative predictive values, respectively. Multiplex PCR to detect Bex and orf 51 identified another 16 MDR Hib cases among 81 culture-negative CSF samples.

CONCLUSIONS

Direct PCR for orf 51 in CSF identified resistance pattern of 51% more Hib strains than culture alone (110 versus 73). The ability to detect MDR, in culture negative Hib meningitis cases has significant implications for better directing antibiotic treatment of meningitis cases and thus for preventing disability and death.

Case management of childhood pneumonia in developing countries

BACKGROUND

Pneumonia is a leading cause of morbidity and mortality in children worldwide. Appropriate management depends on accurate assessment of disease severity, and for the majority of children in developing countries the assessment is based on clinical signs alone. This article reviews recent evidence on clinical assessment and severity classification of pneumonia and reported results on the effectiveness of currently recommended treatments.

METHODS

Potential studies for inclusion were identified by Medline (1990-2006) search. The Oxford Center for Evidence Based Medicine criteria were used to describe the methodologic quality of selected studies.

RESULTS

In the included studies the sensitivity of current definitions of tachypnea for diagnosing radiologic pneumonia ranged from 72% to 94% with specificities between 38% and 99%; chest indrawing had reported sensitivities of between 46% and 78%. Data provide some support for the value of current clinical criteria for classifying pneumonia severity, with those meeting severe or very severe criteria being at considerably increased risk of death, hypoxemia or bacteremia. Results of randomized controlled trials report clinically defined improvement at 48 hours in at least 80% of children treated using recommended antibiotics. However, a limitation of these data may include inappropriate definitions of treatment failure.

CONCLUSION

Particularly with regard to severe pneumonia, issues that specifically need to be addressed are the adequacy of penicillin monotherapy, or oral amoxicillin or alternative antibiotics; the timing of introduction of high-dose trimethoprim-sulfamethoxazole in children at risk for or known to be infected by HIV and the value of pulse oximetry.