Typing of Acinetobacter baumannii isolated from hospital-acquired respiratory infections in a tertiary care centre in southern India

Hospital-acquired Infections in the Adult Intensive Care Unit: Epidemiology, Resistance Patterns, and Risk Factors

INTRODUCTION

Hospital-acquired infections (HAIs) are defined as infections that develop in the patient after being admitted to the hospital. The overall burden of HAIs is known to be higher in developing countries. The most common HAIs include ventilator-associated pneumonia (VAP), catheter-associated urinary tract infection (CAUTI), surgical site infection (SSI), and catheter-related bloodstream infections (CRBSI).

OBJECTIVES

Due to limited recent literature, we aimed to evaluate the incidence rates and causative organisms of intensive care unit (ICU)-acquired infections at our tertiary care center and to determine the factors associated with mortality in patients with ICU-acquired infections.

METHODS

Single-center prospective, observational study.

RESULTS

The incidence rates in our study were: VAP incidence rate: 105/2681 = 39.1/1000 ventilator days, CRBSI incidence rate: 38/4871 = 7.8/1000 central venous catheter (CVC) days, CAUTI incidence rate: 54/11201 = 4.8/1000 urinary catheter days. Acinetobacter baumannii accounted for 41% of the infections in patients with VAP and 21% in patients with CRBSI. E. coli was the most common causative organism in the CAUTI group, accounting for 33% of the infections. Age >50 years, presence of hypotension on presentation, medical diagnosis, multiple ICU-acquired infections, and higher APACHE-II score on admission are the statistically significant determinants of the incidence of mortality in the overall group (p-value >0.05 for all).

CONCLUSION

Age >50 years, presence of hypotension on presentation, medical diagnosis, multiple ICU-acquired infections, and higher APACHE-II score on admission must be kept in mind as determinants of the incidence of mortality in HAIs.

Antimicrobial Susceptibility and Clonal Relation Between Acinetobacter baumannii Strains at a Tertiary Care Center in Turkey

Background:

Acinetobacter baumannii is an opportunistic pathogen, related with nosocomial infections such as bacteremia, urinary tract infections, and ventilator-associated pneumonia. Multidrug resistant (MDR) A. baumannii strains are first line causes of infection, especially in patients hospitalized at intensive care units (ICUs). Infection with MDR A. baumannii strains has a longer duration at ICUs and hospitals. There are studies using molecular methods which can differentiate MDR A. baumannii strains at the clonal level. This helps controlling these resistant strains and prevents their epidemy.

Objectives:

The aim of our study was to investigate the antimicrobial susceptibility and clonal relationship between the A. baumannii strains isolated from our ICU.

Materials and Methods:

The identification and antimicrobial susceptibility of 33 A. baumannii strains were performed by automatized Vitek version 2.0. The clonal relationship among A. baumannii strains was analyzed using enterobacterial repetitive intergenic consensus (ERIC) polymerase chain reaction (PCR).

Results:

A total of 33 A. baumannii strains were included in this study. A. baumannii complex strains were classified into seven clusters based on the fingerprint results. Our results revealed that two main clusters were responsible for the prevalence of A. baumannii complex strains at the ICU.

Conclusions:

MDR A. baumannii strains cause an increment in morbidity and mortality, particularly in ICUs. The use of molecular epidemiological methods can help us with the detection of the pathogen and preventing from spreading of these resistant strains.

The probability of the Acinetobacter baumannii strain clonal spreading in donor-recipient systems, as confirmed by the molecular analysis of randomly amplified polymorphic DNA

Acinetobacter baumannii is an important pathogen widely distributed in the hospital environment and responsible for a variety of nosocomial infections. This micro-organism especially affects patients with impaired host defenses in the intensive care unit. It has been implicated in severe nosocomial infections including bloodstream infections, pneumonia, and meningitides. Those infections are often outbreaks caused by a single clone spreading. The aim of our study was an epidemiological analysis of Acinetobacter baumannii strains isolated from hospitalized liver/kidney transplant donors and recipients. The analyzed material for epidemiological test included 13 A. baumannii strains isolated in 2010 from eight liver/kidney donors and 5 organ recipients. The epidemiological analysis of the isolates was performed by the use of the random amplified polymorphic DNA (RAPD)-polymerase chain reaction method to determine their genetic relatedness. We isolated 9 A. baumannii strains from 8 organ donors. Among this group of isolates, four strains showed the same fingerprints that were classified as one RAPD type 1. The remaining donor isolates revealed differentiated patterns. All strains isolated from recipients formed distinct RAPD types, one of which was identical to the group of four donor strains (RAPD type 1). The clonal spreading of A. baumannii strains was not observed among recipients but we noted a single case of probable transmission of the pathogen from the donor to the recipient.

Outbreak of nosocomial meningitis caused by Acinetobacter baumannii in neurosurgical patients

An outbreak of nosocomial meningitis caused by Acinetobacter baumannii, which developed postoperatively in seven neurosurgical patients is described. The clinical isolates of A. baumannii were typed by biochemical profiles and antibiogram patterns, and by random amplified polymorphic DNA polymerase chain reaction (RAPD-PCR) and amplified fragment length polymorphism (AFLP) fingerprinting. The implicated strain was multi-drug resistant, however, susceptibility to imipenem and netilmicin was detected. An extensive search for the environmental source of the epidemic strain was carried out. Two of several isolates from hospital environment, corresponded to the A. baumannii outbreak strain, one being cultured from the suctioning equipment used in the care of these patients. The introduction of multiresistant epidemic A. baumannii into a neurosurgical unit is a severe risk factor for patients undergoing neurosurgical procedures. Genotypic typing methods are important for definitive identification of these strains in patients and their environment.

Comparison of Acinetobacter baumannii isolates from United Kingdom hospitals with predominant Northern European genotypes by amplified-fragment length polymorphism analysis

Acinetobacter baumannii isolates collected between 1999 and 2001 from 46 United Kingdom hospitals were compared with previously identified northern European genotypes by amplified-fragment length polymorphism (AFLP) analysis. Two predominant northern European genotypes associated with outbreaks in the mid-1980s had been superseded by new outbreak-associated genotypes.

Evaluation of the in vitro activity of six broad-spectrum beta-lactam antimicrobial agents tested against recent clinical isolates from India: a survey of ten medical center laboratories

The widespread use of beta-lactam antimicrobial agents as first-line therapy for the treatment of serious infections has led to the development of various resistances that have compromised the use of some agents. In certain countries, the lack of local or national surveillance programs limits the ability to detect these resistant strains and prevent their dissemination. A 10 medical center study in India was initiated to benchmark prevailing resistance rates for a range of bacterial pathogens to beta-lactams, and it found high rates of beta-lactamase-mediated resistance in Escherichia coli and Klebsiella spp. These rates included: cephalosporins (55.6-61.3% resistance), with extended-spectrum beta-lactamase (ESBL) phenotypes noted in over 60% of E. coli isolates and in Salmonella spp. (3.2-8.1%). Imipenem, a carbapenem, was the only antimicrobial agent tested with 100% activity against Enterobacteriaceae. Cefpirome was the most active of the tested cephalosporins, and all were fully active against methicillin-susceptible staphylococci with the exception of ceftazidime. Molecular and susceptibility characterization of 52 selected ESBL-producing strains showed a high level of co-resistance with aminoglycosides and fluoroquinolones, and clonal dissemination of resistant strains within medical centers. Collaborative studies, such as those presented here, can accurately detect changes in resistance patterns, and their continued use may help limit the further development and spread of bacterial resistances in India.