Profile of Microbial Resistance in a Clinical Laboratory of the Municipality of Itajaí

Special Article – Microbial Resistance

J Bacteriol Mycol. 2018; 5(5): 1078.

Profile of Microbial Resistance in a Clinical Laboratory of the Municipality of Itajaí krusei

Steps JVDM¹*, Valcarenghi D², Schmeling TB³ and Lamb F4

¹University of Vale do Itajaí, Rua Uruguay, Brazil

²Master’s Lecturer in Undergraduate Courses in Biomedicine and Pharmacy, University of Vale do Itajaí, Brazil

³Professor of the Physical Education course, University of Vale do Itajaí, Brazil

4Technical Head of the Laboratory of Clinical Analysis - LEAC, Brazil

*Corresponding author: João Victor de Mattia Passos, University of Vale do Itajaí, Rua Uruguay, Brazil

Received: August 01, 2018; Accepted: September 11, 2018; Published: September 18, 2018


For some time, the presence of microorganisms with mechanisms of resistance were hospital exclusivity. Over the years, it has come into our daily lives, thanks to infections originating from collection points, health units and others, but also by the irrational use of antimicrobial. This work aims to trace the profile of microorganisms with isolated resistance mechanisms of patients attended by a clinical laboratory, the LEAC, located in the municipality of Itajaí, in the period between 2015 and 2016. Such mechanisms were identified in microbiological cultures of uroculture, blood culture, cerebrospinal fluid, coproculture, secretion in general and liquids such as ascitic and pleural. According to the results obtained in this study we can observe the prevalence of AmpC production, isolated, frequently, in cultures of secretion generally evidenced by the high number of strains of Pseudomonas aeruginosa from hospital samples and Escherichia coli isolated from ambulatory urocultures. Based on these data, we may suspect that Pseudomonas aeruginosa has a possible intrinsic resistance to AmpC expression. Microbial resistance is an emerging situation and it is necessary to implant care in these environments so that it does not occur, thus reducing financial costs and the number of deaths.

Keywords: Antibiotic; Bacterium; Outpatient; Hospital


Bacteria are unicellular microorganisms, prokaryotes, contain both DNA and RNA, in their genetic material [1], have a short life span, are able to adapt rapidly to changes in the environment and are found in numerous anatomical sites and can be part of their microbiota or are pathogenic, thus causing infections [2].

Most infections are caused by the imbalance between the human microbiota and host defense mechanisms. This can occur due to the pathological mechanisms of the patient, invasive procedures and changes in the microbial population, which are often generated by the use of antibiotics [3]. Antibiotics are drugs used for the treatment of bacterial infections, produced in order to destroy or inhibit microorganism proliferation [4]. Its use has led to a reduction in the morbidity and mortality rates of these infections worldwide [5], but the use of these drugs causes the pathogen to develop antimicrobial defense mechanisms, making them resistant, causing continuous infections and ineffective treatments [4].

Health Care-Related Infections (IRAS) consist of adverse effects of invasive procedures performed in health facilities, such as Basic Health Units (BHU), collection points, emergency care units, hospital settings [6].

Microbial resistance is a worldwide problem, evidenced by the increase in the number of cases of IRAS caused by microorganisms resistant to the antibiotics used by the population [7].

Today, the indiscriminate use of antibiotics, that is, without medical prescription or without completing the treatment, provides the appearance of multiresistant microorganisms, provoking an outbreak of these biological agents in the population. Resistance cases, which were the reality of hospitals, are spreading to any health establishment, thus being routinely classified [8].

Bacterial resistance to antibiotics is one of the most significant public health problems today, due to the natural phenomenon of selective pressure exerted by its use [9].

When the bacteria present resistance to several classes of antibiotics, they are denominated as multiresistant bacteria, present mainly in Pseudomonas aeruginosa, in enterobacteria and Staphylococcus aureus. They can spread to patients through the hands of health professionals or contaminated equipment, because each Hospital Infection Control Commission (CCIH) has the responsibility to establish a policy of control of these microorganisms [10].

The microorganism acquires antimicrobial resistance through the acquisition of resistance genes, being divided into two types: intrinsic or innate resistance and acquired. The first is a characteristic of a species and dependent on its properties, we can mention the bacterium Escherichia coli that presents intrinsic resistance to vancomycin. Already acquired resistance occurs through mutation or gene transfer [11].

Data from the World Health Organization (WHO) show that more than half of the world’s antibiotic prescriptions are inadequate. The inappropriate consumption of this type of drug is one of the causes that leads to the increase of microbial resistance [7].

The main mechanisms of resistance found today were divided by their morphotinory classification for Gram negative bacteria: through the production of enzymes such as AmpC (AmpC gene), Extended Spectrum Beta-lactamase (ESBL), carbapenemases (KPC) and resistance to polymyxin (MCR1 gene); and for Gram positive bacteria: Methicillin Resistant Staphylococcus aureus (MRSA), Vancomycin Resistant Enterococcus (VRE), Vancomycin Staphylococcus aureus (VRSA), and to terminate the MLSB Inducible Resistance (Macrolides, Lincosamine and Streptogramin B) [12].

AmpC-type beta-lactamase is mediated by plasmids expressing the AmpC gene, which originates from the transfer of the chromosome containing the gene, which has the ability to hydrolyze all beta-lactam antibiotics to 3rd generation cephalosporins. Identified mainly in Escherichia coli, Klebsiella spp, Proteus mirabilis [14].

One of the forms of mechanism of resistance to beta-lactam antibiotics is the production of enzymes, the most important is betalactamase [15].

Extended-spectrum beta-lactamase (ESBL) is mediated by non-inducible plasmid genes, which characterize TEM and SHV enzymes, capable of hydrolyzing the beta-lactam ring present in certain antimicrobials. Due to its spectrum of action can affect the broad spectrum beta-lactams, such as cephalosporins of up to 4th generation and monobacchaeam [16]. This mechanism of resistance is often found in enterobacteria, such as Escherichia coli, Klebsiella pneumoniae, Enterobacter sp [17].

Carbapenemase production (KPC) is a mechanism observed mainly in the bacterium Klebsiella pneumoniae, capable of hydrolyzing a broad spectrum of beta-lactamamines, including penicillins, cephalosporins, monobactams and carbapenems. It has high potential for dissemination because its location is in the plasmid, facilitating its dissemination [18].

Polymyxin is a widely used antibiotic for the treatment of infections by enterobacteria, such as Escherichia coli, Acinobacter baumanii, Pseudomonas aeruginosa and Klebsiella pneumoniae that present resistance mechanism. Over the years, these bacteria have acquired resistance to this antimicrobial, as it changes the posttranslational modification of lipopolysaccharide (LPS), altering the permeability of polymyxin at the target site. This situation is due to the acquisition of a plasmid containing the colistin resistance gene, mcr-1 [19].

One of the mechanisms expressed by Staphylococcus aureus is the coding of altered penicillin-binding protein (PBPs), termed PBP2a, consequently, no affinity to all beta-lactam antibiotics occurs. Such resistance is known as methicillin-resistant Staphylococcus aureus (MRSA) and the gene encoding this synthesis is mecA [20].

The mechanism of resistance involving the genus Enterococcus resistant to Vancomycin (VRE) occurs through the acquisition of the van gene (the types vanA and vanB are the prevalent) [21], through mutation or gene transfer, present in transposons [22]. There is a mutation in the terminal peptide, resulting in a D-alanyl-D-lactate residue, instead of D-alanyl-D-alanyl [23] which results in an altered peptideoglycan in the cell wall provoking little affinity to vancomycin, inhibition of its action on the blockade of cell wall synthesis [24].

Resistance to the MLSB group (Macrolide, Lincosamide, Streptogramina B) causes alteration in ribosomal antibiotic binding sites mediated by erm (erythromycin methylase ribosomal) gene [25]. This gene encodes enzymes that reduce the binding of MLSB class antibiotics to ribosomes [26]. Clindamycin is an antibiotic used for the treatment of Staphylococcus aureus infections because it acts on RNA and ribosomes. However, misuse of MLSB class antimicrobials led to resistance by several mechanisms, such as decreased permeability, altered ribosomal action site, enzymatic action and efflux pumps [27].

This work aims to trace the microbial resistance profile of patients attended by a clinical laboratory in the city of Itajaí to provide epidemiological data that help in the control of cases of bacterial resistance. Also, it can be used as a subsidy for protocol changes in the selection of antimicrobials in relation to the optimization of the laboratory routine.

Materials and Methods

This was a cross-sectional descriptive research based on a documental analysis of data from patients attending the Laboratory of Clinical Analyzes (LEAC) at the University of Vale do Itajaí (UNIVALI), located in the city of Itajaí - SC, in the 2015 to 2016.

In this period, 9123 requests were made for microbiological cultures, such as uroculture, coproculture, liquor, blood culture, secretion in general (composed of ear secretion, abscess, osteomilite, wound, tracheal aspirate and catheter tip) and liquids such as ascites and pleural .

The samples were categorized as outpatient clinics: from the request of doctors to the Unified Health System (SUS), Family and Community Health Unit, dental clinic (both located at UNIVALI), private agreements; and hospital: from medical requests from Hospital University Little Angel (HUPA).

The laboratory provided the data regarding the date of collection, culture results and antibiograms of patients who were identified exclusively with the protocol number generated by their management system, TASY®, thus ensuring safety and confidentiality. These data were tabulated, using absolute and relative frequency, using Microsoft Excel®.


The project was approved by the Research Ethics Committee (CEP) in humans of the University of Vale do Itajaí - UNIVALI, under the opinion number 2,267,570/2017.

Results and Discussion

In the years 2015 to 2016 a total of 9% (828/9123) microbiological cultures with bacterial growth of hospital and outpatient samples were performed by the Laboratory of Clinical Analysis (LEAC). Of the positive cultures, 15% (126/828) presented microorganism with resist Staphylococcus aureus ance mechanism, with a predominance of 62% (78/126) AmpC, 25% (31/126) ESBL, 6% (8/126) MRSA and Resistance to Macrolide, Lincosamide and Streptogramin B (RMLSB) group, 1% (1/126) KPC and 0% VRE, VRSA and Polymyxin Resistance. Only 1 (one) multiresistant microorganism characterized by AmpC and ESBL has been identified, this is Escherichia coli isolated from an outpatient uroculture.

In a study conducted in Iran by Ghotaslou et al. (2018) [28] analyzed samples from medical centers, obtaining 52.8% of microorganisms with resistance mechanism. Such a value is higher than the one found here, 15%. Still the prevalence was ESBL 42.7%, followed by 14% AmpC production and 4.9% carbapenemase.

Figure 1 shows the frequency of resistance mechanism of hospital samples from the years 2015 and 2016. A total of 66% (83/126) of positive microbiological cultures with resistance mechanism was identified. Of these, there was a predominance of AmpC, 60% (50/83), accompanied by 23% (19/83) ESBL, 10% (8/83) MRSA, 7% (6/83) RMLSB and finally 0% KPC and VRE (Figure 1).