**3. Microbiological investigations**

Microbiological evaluation is mandatory for an adequate therapeutic regimen; accurate identification of the bacterial species is essential to avoid administration of broad-spectrum antibiotics. The optimal recovery of the pathogens ultimately depends on the accuracy of sample collection (sputum, endotracheal aspirate, or bronchoscopically obtained specimens by bronchoalveolar lavage). Bacteriological assessment of lower respiratory tract infections begins with care evaluation of Gram-stained smear performed from respiratory tract specimen. The low-power scanning provides a first sight of the quality of the sample—for sputum more than 10 squamous epithelial cells show oropharyngeal contamination. The examination with the oil immersion provides more details regarding bacterial morphology. The importance of this step in the management of bacterial pneumonia is well recognized. As illustrated in **Figures 1** and **2**, it is possible to anticipate the diagnosis toward a nonfermenter or an *Enterobacteriaceae*. *Acinetobacters* are short Gram-negative nonsporing bacilli but in exponential phase became coccoids often arranged in diplo. Many strains are encapsulated and sometimes retain the methyl violet in Gram's stain. The *Enterobacteriaceae* appear typically as Gram-negative nonsporing bacilli with parallel sides and rounded ends. There are wide ranges of derivatives from this classical appearance, from filamentous rods to coccoids. Some species are encapsulated, for example, *Klebsiella*, sometimes *E. coli.*

injured patients—VAPs and burn patients—are most prone to infection with carbapenemresistant species. The chief question for carbapenem-resistant Gram-negative bacillary pneumonia is how to efficiently prevent them. First of all, could these infections be stopped? In the hospital environment, hand hygiene and alcohol-based disinfection remain, undeniably, the sanitation gold standard. Rigorous monitoring of patients at admission and an accurate history are early stages in identification of patients with documented multidrug-resistant strains for further isolation or, at least clustering separately to prevent the risk of cross-contamination [25, 26]. Respiratory contamination depends on so many circumstances, almost impossible to eliminate, that the specific strategies are designed in order to reduce VAP, rather than to eliminate such infections [27]. What else could be taken in consideration apart from already established strategies? As it was underlined in introduction, from the ancient times, people are aware of the so-called air purification performed intuitively by burning scented substances or

The Emerging Problems of Carbapenem-Resistant Gram-Negative Bacillary Pneumonia

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Antibiotic regimens of carbapenem-resistant bacillary pneumonia often rely only on few antibiotics. Although there is not an ideal therapeutic regimen for the treatment of pneumonia due to carbapenem-resistant species, Polymixin B, Tigecycline, and Amikacine remain the most valid options [28]. A prerequisite for adequate treatment of VAPs is intravenous administration of the suitable antibiotic. Aerosolized antibiotics delivery has been experimentally studied in order to reduce the side effects of systemic administration of antibiotics. Efficiency of these methods relies on the antibiotics' ability on crossing the alveolar-capillary membrane [29]. An abundant literature is devoted to the issue of carbapenem-resistant strains. Because antibiotic resistance continuously evolved, clinical guidelines rapidly changed, therefore, a unique treatment scheme is almost impossible to establish. Clearly, we must look at the information provided by extensive epidemiological studies to up-date infection control and treat-

In spite of specific protocols implemented in ICUs, it is worthwhile to consider additional methods to prevent respiratory contamination. We should be considering the inhibitory effect of some essential oils (EOs), underlining the efficiency of volatile substances. EOs are more and more regarded as complementary to antibiotic therapy [31–35]. In our previous work, we demonstrated the high activity of EOs against *E. coli* for coriander (*Coriandrum sativum* L.),

We are interested in evaluating of the efficiency of some EOs against carbapenem-resistant *Acinetobacter baumannii* and *E. coli* ATCC 25922. *A. baumannii* is a ubiquitous nonfermenter species, found in soil, water, and clinical units, and *E. coli* is a constant presence of the normal microbiocenosis of humans and warm-blood animals. Of hundreds of natural products

peppermint (*Mentha piperita* L.), and juniper (*Juniperus communis* L.) [36].

widespread use of all sorts of perfumes, plant extracts, or spices.

**4.2. Antibiotic therapy**

ment options [30].

*4.3.1. Materials and methods*

**4.3. Inhibitory activity of essential oils**

**Figure 1.** High-power examination (1000× magnification). Gram-stained smear of endotracheal aspirate shows Gramnegative coccobacilli isolated or in diplo (*Acinetobacter* spp.).

**Figure 2.** High-power examination (1000× magnification). Gram-stained smear of endotracheal aspirate shows Gramnegative capsulate rods.

Since this chapter is not intended to be a highly elaborate description of bacterial diagnosis of Gram-negative bacillary pneumonia, further details about isolation and bacterial identification were not be reviewed. However, the microscopic examination of clinical sample offers essential clues about the nature of bacterial infection. For busy clinicians—in ICUs the physicians have always needed a microbiologic response as quickly as possible—these details, provided in advance, could make the difference.
