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Table of Contents   
ORIGINAL ARTICLE  
Year : 2015  |  Volume : 8  |  Issue : 5  |  Page : 164-176
The dynamics of bacteria population on the skin, throat, and gastrointestinal tract of HIV-seropositive patients


1 Department of Microbiology, College of Health Sciences, Obafemi Awolowo University, Ile-Ife, Osun State, Nigeria
2 Department of Biological Sciences, College of Science, Engineering and Technology, Osun State University, Osogbo, Osun State, Nigeria
3 Department of Paediatrics and Child Health, College of Health Sciences, Obafemi Awolowo University, Ile-Ife, Osun State, Nigeria
4 Department of Haematology, State Specialist Hospital, Akure, Ondo State, Nigeria
5 Department of Microbiology, College of Medicine, Howard University, Washington DC, USA

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Date of Web Publication21-Sep-2015
 

   Abstract 

Background: The study determined bacteria population on the skin, throat, and gastrointestinal tract of human immunodeficiency virus (HIV)-seropositive patients and HIV seronegative controls at the baseline, 3 months, and 6 months, respectively, at Obafemi Awolowo University Teaching Hospitals Complex (OAUTHC), Ilé-Ifè, Osun State, Nigeria and State Specialist Hospital, Akure, Ondo State, Nigeria between May and November, 2012. Materials and Methods: Seventy HIV-seropositive subjects and 51 HIV seronegative controls who attended the HIV clinics were recruited. Skin, throat, and rectal swabs were obtained from the participants using sterile cotton-tipped applicators introduced into thioglycollate broth and incubated at 37°C overnight. When growth was noticed, the broth culture was streaked on different bacteriologic media and the isolates were characterized by the standard methods and disc diffusion for antibiotic sensitivity. Results: The number of isolates cultured from the HIV-seropositive subjects was 934, with the distribution being 397, 326, and 211 at the baseline, 3 months, and 6 months, respectively. The distribution of 1,138 isolates cultured from 51 HIV-seronegative controls was 433, 354, and 351 at the baseline, 3 months, and 6 months, respectively. At the baseline among HIV-seropositive patients, the predominant isolates were Arcanobacterium haemolyticum, Pseudomonas aeruginosa (P. aeruginosa), and Bacillus cereus (B. cereus). However, Corynebacterium haemolyticum, Enterococcus faecalis, and Escherichia coli (E. coli) were predominant at 3 months while at 6 months, Corynebacterium haemolyticum and Corynebacterium diphtheriae had the highest frequency followed by Pseudomonas fluorescens (P. fluorescens). In the controls, Corynebacterium diphtheriae, Listeria monocytogenes, and Staphylococcus xylosus (S. xylosus) predominated at the baseline and at 3 months while at 6 months, B. cereus, S. xylosus, and Staphylococcus aureus (S. aureus) were prevalent. Multiple resistances were widespread among the isolates. Conclusion: A preponderance of opportunists was observed in the HIV-seronegatives but higher multiresistant strains in the HIV-seropositives, suggesting both groups live in an antibiotic pressurized environment.

Keywords: Bacterial population, cluster of differentiation 4 (CD4) cell count and RNA viral load, dynamics, human immunodeficiency virus (HIV) infection, multiple antibiotic resistance (MAR) index, multiresistance

How to cite this article:
Ako-Nai KA, Adeyemi FM, Adejuyigbe EA, Ebhodaghe BI, Osho PO, Kassim OO. The dynamics of bacteria population on the skin, throat, and gastrointestinal tract of HIV-seropositive patients. Ann Trop Med Public Health 2015;8:164-76

How to cite this URL:
Ako-Nai KA, Adeyemi FM, Adejuyigbe EA, Ebhodaghe BI, Osho PO, Kassim OO. The dynamics of bacteria population on the skin, throat, and gastrointestinal tract of HIV-seropositive patients. Ann Trop Med Public Health [serial online] 2015 [cited 2019 Oct 13];8:164-76. Available from: http://www.atmph.org/text.asp?2015/8/5/164/165844

   Introduction Top


With a population of 170 million people, Nigeria ranks third in the world's heaviest burden of human immunodeficiency virus/acquired immune deficiency syndrome (HIV/AIDS) following India and South Africa. [1] Approximately 3.1% of the Nigerian population lives with HIV/AIDS. [1] The prevalence of HIV/AIDS in Nigeria varies from one state to another. [2] It is fast becoming the disease of poverty among pregnant peri-urban women, infants, and children who bear a disproportionate burden as a result of heterosexual transmission. [3] About 80-95% of HIV/AIDS transmission in Nigeria is due to heterosexual contact. [3] Similarly, 70,000 infants annually acquire HIV through mother-to-child transmission (MTCT), marking the country with the highest on the globe. HIV infection depresses both innate and cell-mediated immunities. Studies have shown that antigen presenting cells such as macrophages, dendritic cells, and to a lesser extent B lymphocytes are functionally impaired in HIV infection. [4] HIV-positive individuals are also at a high risk of opportunistic infections including infestation of parasites and various bacterial pathogens including Mycobacterium intracellulare, Klebsiella pneumoniae, and Pneumocystis jirovecii among others. [5] HIV infection causes a decline in cluster of differentiation 4 (CD4) cells below the critical level of 200 cells/, [5] Studies have shown that proinflammatory cytokines play an important role in both the control and pathogenesis of HIV infection. [6] HIV also dysregulates pathways to cytokine expression so that the production of the proinflammatory cytokines interleukin-12 (IL-12) and interferon gamma (IFNγ) is decreased and the expression of the anti-inflammatory cytokine IL-10 is increased. [7] It has been reported that HIV also upregulates the adhesion molecules on endothelial cell(s), which may compound the adherence and sequestration seen in malaria. [6]

HIV infection has been also shown to decimate CD4 cells causing apoptosis of the immune cells. The skin is the largest organ in the human body harboring myriad of resident microflora. The mucosal surface of the gastrointestinal tract creates a unique anatomical and physiological environment that serves as a predominant barrier against invading microorganisms. [8] An HIV-infected individual suffers from significant gastrointestinal pathology than HIV-uninfected individuals. [8],[9] The gut-associated lymphoid tissue (GALT) is a unique site for early HIV replication and severe CD4 cell depletion. Studies have revealed that the breakdown of the mucosal surface can lead to microbial translocation, a major factor that complicates HIV/AIDS progression. [10] Therefore, persistent viral replication in the GALT has been shown to be responsible for the replenishment and maintenance of the viral reservoirs seen in an HIV/AIDS patient.

Our study suggests that the damage that occurs in the lumen of the gastrointestinal tract, including the skin, during acute and chronic phases of HIV infection probably through microbial translocation may affect the dynamics of bacterial population in HIV-infected patients compared with HIV-uninfected controls. This study, therefore, investigated and compared the dynamics of the changing bacterial population cultured from the skin, throat, and gastrointestinal tract (rectal swab) of HIV seropositive subjects and HIV seronegative controls at the following three separate periodic intervals: baseline, 3 months, and 6 months, respectively. The antibiotic resistance pattern of bacterial isolates cultured from these sites was compared since such studies have never been conducted in this environment. It is anticipated that the results obtained from this study will assist clinicians to better manage bacterial infections among highly vulnerable HIV-infected patients as well as HIV-seronegative controls in the event of severe infections caused by these organisms in an antibiotic pressurized environment.


   Materials and Methods Top


Methods of sample collection

Samples from the throat, rectum, and skin were collected from each participant by the attending physician. The throat and rectal swabs were collected using sterile cotton-tipped applicators (Evepon Industrial Limited, Onitsha, Anambra State, Nigeria). Sterile cotton-tipped applicators (Evepon Industrial Limited, Nigeria) were also used to collect samples from the skin of the elbow of the left hand (5-cm radius) from each patient for the sake of uniformity. The cotton-tipped applicator was dipped into sterile saline before the collection. Small portions of the fecal material on the rectal swabs were initially streaked onto eosin-methylene blue (EMB) agar and MacConkey agar, and then each sample was inoculated into thioglycollate broth. All the samples were processed within 24 h of collection. Throat, rectal, and skin samples were also obtained from the HIV seronegative controls at these centers and processed for bacteria, as described for the HIV-seropositive subjects.

Estimation of bacterial load

The bacterial load for each sample was determined by plating out the serial dilutions of each sample collected in thioglycollate broth using the pour plate technique. The colonies on each plate were counted after incubation at 37°C for 48 h to estimate the number of colony-forming units (CFUs) per sample. The plates that had more than 300 colonies or less than 30 colonies were disregarded.

Criteria for study inclusion

The HIV serostatus of each participant was determined by blood screening at the HIV clinic of the hospital and was a requirement for inclusion in the study. Furthermore, approval to carry out the study was obtained from the Ethics Committee of the institutions. (Ondo State Hospital Management Board, Akure, Ondo State, Nigeria and OAUTHC, Ethics Committee, Ilé-Ifè., Osun State, Nigeria). The participants were interviewed, adequately informed, and counseled in their native dialect before being enrolled in the study.

Screening for HIV among participants

A 4-mL volume of blood was collected from each participant. A small aliquot was applied onto the HIV-1/2 strip (Determine Test, Alere, London, England, UK) for the preliminary determination of HIV serostatus. Confirmatory test for HIV infection was performed using the Abbott enzyme-linked immunosorbent assay (ELISA) procedure (Abbott Laboratories, Chicago, IL Il, USA).

Bacterial isolation, identification and antibiotic sensitivity tests

The bacterial isolates were identified by Gram stain and growth characteristics on mannitol salt agar (Oxoid, Basingstoke, Hampshire, England, UK), blood agar, EMB agar, ChromoBio TBX, Hi Chrome agar, triple sugar iron agar (Sigma-Aldrich, Co., St Louis, MO, USA), sulfide indole motility medium, citrate agar (Oxoid, Oxoid Basingstoke, Hampshire, England, UK), and analytical profile index (API) rapid biochemical test. The API kits used include API 20E and API Staph (bioMérieux, France). Coagulase, catalase tests, sensitivity to Taxo A disc (0.04 units of bacitracin) and Taxo P (5 μg), and ethylhydrocupreine hydrochloride (optochin; BD Diagnostics, Difco Laboratories, Detriot, MI, USA) were also employed for identification. All the bacterial isolates were tested for their sensitivity to commonly prescribed antibiotics using the Kirby-Bauer method. The antibiotics used were obtained from Oxoid (Basingstoke, Hampshire, England, UK) and included amikacin (AMK) (30 μg), amoxicillin/clavulanic acid (AMC) (20 μg), ampicillin (AMP) (10 μg), cefoxitin (FOX) (30 μg), ceftazidime (CAZ) (30 μg), ceftriaxone (CRO) (30 μg), cefuroxime (CXM) (30 μg), cephalothin (KF) (30 μg), ciprofloxacin (CIP) (5 μg), erythromycin (ERY) (15 μg), gentamicin (GEN) (10 μg), imipenem (IPM) (10 μg), kanamycin (KAN) (30 μg), ofloxacin (OFX) (5 μg), oxacillin (OXA) (1 μg), streptomycin (STR) (10 μg), trimethoprim (TRI) (5 μg), and vancomycin (VAN) (30 μg). Staphylococcus aureus (S. aureus) American Type Culture Collection (ATCC) 25923 and Enterobacter aerogenes ATCC 13042 (ATCC, Rockville, MD, USA) were used as the control organisms.

CD4 T cell count and HIV viral load

A 20-μL aliquot of blood was processed to generate the CD4+ cell count by flow cytometry (CyFlow Counter SL-3, Partec, Otto-Hahn-Strasse 32-48161 Muenster, Germany) within 6 h of blood collection. A 20-μL volume of CD4+ monoclonal antibody conjugated to phycoerythrin was also added to the blood sample. The mixture was incubated for 15 min at room temperature in the dark after which 800 μL of no-lyse buffer was added and gently vortexed. The blood mixture was pipetted to the appropriate port of the CyFlow Counter for CD4+ T cell analysis and enumeration. A multiset software was used to obtain the absolute CD4 cell count. For the determination of the HIV viral load, the plasma was separated from the whole blood by centrifuging at 3,000 rpm for 5 min at room temperature, aliquoted, and stored at -80°C until it was needed for analysis. The HIV-1 RNA concentrations were determined by the quantitative nucleic acid sequence-based Amplicor HIV-I monitor assay (Roche version 1.5, Basel, Switzerland).

Statistical analysis of data

Statistical evaluation was done using independent t-test and one-way analysis of variance (ANOVA) with P ≤ 0.05 as the indicator of statistical significance. SPSS 16.0 (Chicago, IL, SPSS Inc., 2007) for Windows ® was used to perform the analyses.


   Results Top


A total of 934 bacteria isolates were cultured from the 70 HIV-seropositive subjects, with the distribution being 397 bacterial isolates at the baseline, 326 isolates at 3 months, and 211 isolates at 6 months. At the baseline, 120 (30.2%), 112 (28.2%), and 165 (41.6%) bacterial isolates were cultured from the skin, throat, and rectal swabs averaging 1.7, 1.6, and 2.4 bacteria per sample, respectively.

A total of 397 isolates across 19 bacterial genera comprising 31 species were cultured with Bacillus spp. (17.4%) being the predominant one followed by Corynebacterium spp. (16.6%) and Pseudomonas spp. (15.6%). Out of the 397 bacterial isolates recovered from the three different sites, 248 (62.5%) were gram-positive bacteria comprising 159 (40.1%) rods and 89 (22.4%) cocci while 149 (37.5%) were gram-negative bacteria comprising 31 (7.8%) lactose fermenters and 118 (29.7%) non-lactose fermenters. The single most predominant bacteria isolated was Corynebacterium haemolyticum (12.3%) followed by Pseudomonas aeruginosa (P. aeruginosa) and Bacillus cereus (B. cereus) (9.3% each). Bacillus subtilis (B. subtilis) and Pseudomonas fluorescens (P. fluorescens) constituted of 8.1% and 6.3%, respectively. Of the gram-positive rods cultured, Bacillus spp. (made up of B. cereus and B. subtilis) dominated at 43.9% followed by Corynebacterium spp. at 41.5% comprising Corynebacterium haemolyticum (72.8%), and Corynebacterium diphtheriae (27.1%). At 3 months, 326 bacterial isolates were recovered with 17 bacteria genera consisting of 27 species across the three sites; the predominant genus was Corynebacterium spp. (19.9%) followed by Staphylococcus spp. (14.1%). The predominant bacterial isolate was also Corynebacterium haemolyticum (12.3%) followed by Enterococcus faecalis (11.7%) and Escherichia coli (E. coli) (11.0%). At the first follow-up of 3 months, 100 (30.7%), 71 (21.8%), and 155 (47.5%) isolates were cultured from the skin, throat, and rectal swabs averaging 1.9, 1.4, and 3.0 bacteria per sample, respectively, while at 6 months, 23 species within 18 genera were cultured. Corynebacterium spp. (29.9%) followed by Staphylococcus spp. 11.8% were also the predominant organisms consisting of Corynebacterium haemolyticum and Corynebacterium diphtheriae that incidentally had the highest frequencies at 39 (18.5%) and 24 (11.3%), respectively. This was followed by P. fluorescens (9.5%). Fifty eight (27.5%) isolates each were recovered from the skin and throat and 95 (45.0%) isolates were cultured from the rectal swabs, averaging 1.7 bacteria per sample for the skin and the throat and 2.7 bacteria per sample for the rectal samples [Table 1].
Table 1: Distribution of bacterial isolates cultured from HIV-seropositive patients at the baseline, 3 months, and 6 months

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On the contrary, 1,138 bacterial isolates were cultured from the 51 HIV-seronegative individuals with the distribution being 433 isolates at the baseline, 354 isolates at 3 months, and 351 isolates at 6 months. At the baseline, 147 (33.9%), 113 (26.1%), and 173 (40.0%) isolates were cultured from the skin, throat, and rectal swabs averaging 2.9, 2.2, and 3.3 bacteria per sample, respectively, cutting through 19 bacteria genera consisting of 32 species cultured at the baseline. At 3 months, however, 110 (31.1%), 117 (33.0%), and 127 (35.9%) isolates were obtained from the skin, throat, and rectal swabs averaging 2.4, 2.5, and 2.8 bacteria per sample, respectively, consisting of 18 genera with 31 species and at 6 months, 118 (33.6%), 94 (26.8%), and 139 (39.6%) isolates each were cultured from the skin, throat, and rectal swabs averaging 2.8, 2.2, and 3.3 bacteria per sample, respectively, of 16 genera with 26 species. Corynebacterium spp. (25.9%) comprising Corynebacterium haemolyticum and Corynebacterium diphtheria, Listeria monocytogenes (9.2%), and Staphylococcus xylosus (S. xylosus) (6.5%) were the predominant isolates at the baseline as well as at 3 months with the distribution being 47 (13.3%), 42 (11.9%), and 31 (8.7%) for Corynebacterium haemolyticum, S. xylosus, and Listeria monocytogenes, respectively. At 6 months, however, Staphylococcus spp. (39.9%), predominantly S. xylosus (12.5%) and S. aureus (11.1%), and Bacillus spp. (24.5%) consisting of B. cereus (16.0%) and B. subtilis (8.5%) were the major organisms involved. This was followed by Corynebacterium spp. (14.3%) [Table 2].
Table 2: Distribution of bacterial isolates cultured from HIV-seronegative patients at the baseline, 3 months, and 6 months

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A total of 250 bacterial isolates, 137 from HIV-seropositive and 113 from HIV-seronegative individuals were subjected to antibiotic susceptibility testing employing 18 different antibiotics. Of the test organisms from HIV-seropositive individuals, 86.1% were resistant to more than three classes of antibiotics, with 69.5% being gram-positive and 30.5% being gram-negative bacteria. Of the total gram-positive organisms, 82.8% were multiresistant while all the gram-negative organisms except two strains of P. fluorescens (94.7%) were multiresistant. However, among the HIV-seronegative control group, 65.5% of cultured organisms were multiresistant, with 55.4% being gram-positive and 44.6% being gram-negative. Of the total gram-positive isolates, 51.3% were multiresistant while all the gram-negative organisms were multiresistant (100.0%).


   Discussion and Conclusion Top


The study determined the dynamics of bacterial population from the skin, throat, and gastrointestinal tract (rectal swab) of HIV-seropositive subjects at the OAUTHC, Ilé-Ifè., Osun State, Nigeria and the State Specialist Hospital, Akure, Ondo State, Nigeria and compared them with the samples recovered from the HIV-seronegative controls. A total of 2,072 bacterial isolates were cultured from the three sites across three different time intervals. Among the HIV-seropositive patients at the three periodic intervals, 934 (45.1%) were recovered from seropositive patients while 1,138 (54.9%) bacterial isolates were recovered from HIV-seronegative individuals, underscoring the preponderance of recovery of bacterial isolates among the seronegative individuals.

Overall, gram-positive bacteria recovered from the HIV-seropositive and seronegative controls were compared. Of the total 1,527 gram-positive bacterial isolates recovered from both seropositive patients and seronegative individuals, 618 (40.5%) were from 70 HIV-seropositive individuals compared to 909 (59.5%) of 51 controls consisting of 248 (40.1%) at the baseline, 216 (34.9%) at 3 months, and 154 (24.9%) at 6 months [Table 3]. On the contrary, of the 909 bacterial isolates cultured from 51 HIV-seronegative individuals, 318 (34.9%) at the baseline, 292 (32.1%) at 3 months, and 299 (32.9%) at 6 months were recovered. The results show that Corynebacterium haemolyticum was the predominant organism recovered from both the groups. However, Staphylococci dominated 464 (30.4%) among the gram-positive organisms and of these, S. aureus was the single predominant organism 119 (25.6%) followed by Corynebacterium [420 (27.5%)] and Arcanobacterium haemolyticum predominated [Table 4]. Our study shows the preponderance of opportunists such as Bacillus spp. and Corynebacterium spp. in both HIV-seropositive and HIV-seronegative subjects across the three sampling sites and period. The frequency of recovery of opportunists in the urine of HIV-seropositive malaria-infected pregnant women with urinary tract infection (UTI) has been reported by Ako-Nai et al.[11],[12],[13] Similar to our study, Bacillus spp., mainly B. cereus and B. subtilis, and Corynebacterium spp. were cultured, suggesting that these bacteria may no longer be always considered contaminants in these individuals.
Table 3: Dynamics of gram-positive bacteria recovered from HIV-seropositive and control subjects

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Table 4: Dynamics of gram-negative bacteria recovered from HIV-seropositive and control subjects

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The results of antibiotic resistance of isolates cultured from HIV-seropositive patients show that 97.8% of them were resistant to FOX followed by CXM (94.9%), CAZ (94.2%), and AMP and KF at 86.1% each. Similarly, 82.5% of the isolates were resistant to OXA and 81.8% resistant to CRO. This high level of multiresistance suggests that the isolates were most likely to be extended spectrum beta-lactamase producers. [11] On the contrary, when isolates cultured from HIV-seronegative individuals were analyzed, the resistance values were lower. Of the isolates tested, 69.0% were resistant to AMP, 55.8% to TRI, 49.6% to OXA, 45.1% to FOX, and 42.5% to VAN. However, all the isolates cultured from HIV-seronegative individuals were susceptible to IPM while 1.8% were resistant to AMK and 3.5% to gentamycin.

All the P. aeruginosa isolates cultured from HIV-seropositive patients were resistant to AMP, OXA, FOX, CXM, KF, VAN, and ERY while 91.7% of them were resistant to augmentin (amoxicillin with clavulanic acid), CRO, KAN, and TRI. Similarly S. aureus isolates also exhibited some degree of multiple-resistance, 66.7% of which were resistant to three or more different classes of antibiotics. Similarly, all the E. coli isolates were multiresistant, being resistant to more than three classes of antibiotics [Table 5]. The presence of such multiresistant strains on the body sites of immune-compromised individuals portends serious implication in view of the fact that these organisms have also been known to cause recurrent infections. [14]
Table 5: Profile of multiple resistance among predominant isolates cultured from HIV-seropositive patients

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P. aeruginosa is a leading cause of nosocomial infections, especially in immune-compromised patients. Multidrug-resistant P. aeruginosa has been shown to possess several mechanisms of antimicrobial resistance such as overexpression of the intrinsic AmpC-type cephalosporinase that confers resistance to CAZ and inactivation or downregulation of the outer membrane porin D (OprD) that confers resistance to the carbapenems. In addition, the expression of the efflux pump has been implicated in resistance of Pseudomonas spp. to β-lactam antibiotics. These proteins transport the antibiotics from within the cell to the external environment. Upregulation of the MexAB-OprM or other efflux pumps of the resistance-nodulation-cell division family has been shown to confer resistance to carbapenems as well as to quinolones and in some cases to aminoglycosides. [15] This multidrug system has been shown to provide resistance to a very wide range of compounds in gram-negative bacilli [16],[17] coupled with a low permeability of the outer membrane [18] and a remarkable ability to acquire further resistance mechanisms to multiple groups of antimicrobial agents including β-lactams, aminoglycosides, and fluoroquinolones. [19] It is notable that many of the resistant mechanisms are often present simultaneously, thereby conferring multiresistance to the organism. [20]

In spite of the high degree of resistance among isolates from HIV-seropositive patients recorded in this study, it is interesting to note that a considerable number of the isolates were sensitive to IPM and gentamycin. Only 10 out of the 137 (7.3%) isolates cultured from HIV-seropositive patients were resistant to IPM while 10.9% of them (15 out of 137) were resistant to gentamycin, a trend that is similar to that seen among isolates from HIV-seronegative individuals. Altogether, the results obtained in this study revealed that resistance to IPM and gentamycin was 4.5% for Pseudomonas spp., 0% for E. coli, and 13.3% for S. aureus each. This finding corroborates with previous studies in which the investigators reported that antibiotic resistance patterns of P. aeruginosa to IPM had been found to be lower than other antibiotics in other studies. [21],[22],[23],[24] It has been suggested in other cases that the efficacy of gentamycin may be related to the mode of its administration, which has limited its abuse and misuse.

When the population dynamics of gram-negative bacteria from HIV-seropositive and seronegative were compared, 545 isolates were cultured from both the groups. Total 316 (57.9%) bacterial isolates were cultured from HIV-seropositive patients compared to 229 (42.9%) isolates from HIV-seronegative controls. P. aeruginosa (40.6%) and P. fluorescens (59.4%) were the predominant bacteria but the single most common species was the P. fluorescens when compared with the HIV-seronegative individuals among whom only 16 isolates were recovered [Table 3] and [Table 4]. The multiple antibiotic resistance (MAR) index was also calculated [Figure 1]. The results revealed that 91.9% of the isolates cultured from HIV-seropositive patients had MAR indices above 0.2 while only 44.5% of the bacteria isolated from HIV-seronegative individuals had MAR indices above 0.2. The results also show that the MAR indices in this study were >0.2 in 95.5% of Pseudomonas spp., 86.7% of S. aureus, and 100% for E. coli isolated from HIV-seropositive patients, suggesting an antibiotic pressurized community. The MAR indices were also >0.2 in 40% and 64% for S. aureus and E. coli, respectively, from HIV-seronegative individuals. This reveals that the percentage of individual isolates that had high MAR indices from the HIV-seronegative individuals were considerably lesser than that in the HIV-seropositive study group. MAR indexing is an effective as well as a useful tool for evaluating the spread of bacterial resistance in a given population. [25] The high MAR indices of organisms isolated from the HIV-seropositive cohort in this study pose a challenge to the clinical management of these immune-compromised individuals.
Figure 1: The MAR index pattern of bacterial isolates

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Interestingly, HIV disease progression is generally slow despite the damage to the intestinal mucosa that leads to translocation of microbes from the intestinal lumen into circulation. With considerable damage to both the immunological and structural barriers of the gastrointestinal tract occurring over a short period of acute phase of HIV infection, studies have provided direct links between the damage to gastrointestinal tract in the acute phase of infection and disease progression. Brenchley et al,[9] reported increased levels of plasma lipopolysaccharides (LPSs) in individuals chronically infected with HIV compared with uninfected individuals. According to these investigators, the raised LPS levels results from microbial translocation due to damage to the gastrointestinal tract during the acute phase of HIV infection. In addition, these investigators observed that increased LPS circulation is associated with increased levels of soluble CD12 and LPS-binding protein and decreased levels of antibodies against LPS core antigen. Studies undertaken by Pilakka-Kanthikeel et al. [26] also observed that HIV-infected children who did not receive highly active antiretroviral therapy (HAART) suffered from more pronounced microbial translocation associated with immune activation. Despite the fact that the mechanisms by which microbial translocation causes immune activation is still poorly understood, studies have shown that the key pathogenic event seems to be innate immunity activation via toll-like receptors and other pathogen recognition receptors. Furthermore, Marchetti et al.[27] observed that microbial translocation could affect HIV progression, response to therapy, and non-AIDS comorbidities. All except one of the HIV-seropositive patients were in the asymptomatic stage in our study according to the World Health organization (WHO) staging protocol.


   Conclusion Top


In conclusion, antimicrobial resistance is an increasing problem worldwide. In Nigeria, antibiotic resistance is a major problem in our health institutions where most of the agencies lack effective antibiotic policy. The study revealed the colonization of HIV-seropositive and HIV-seronegative individuals with pathogens, mainly P. fluorescens and P. aeruginosa, as well as S. aureus that may be indicative of constant use or misuse of antibiotics in the environment. Furthermore, our data reveal that antibiotic resistance is widespread among both the groups but higher in immune-compromised subjects than in the HIV-seronegative controls. The preponderance of opportunistic bacteria population in HIV-seronegative controls is interesting and suggests the important role microbial antagonism plays in controlling the number of pathogens probably in these individuals in the event of infection. In addition, the fluctuation in terms of the types and numbers of bacterial flora across the three sampling sites suggests the changing patterns of bacterial population among these two groups that may be due to several factors including antibiotic use, diet, antiretroviral (ARV) sensitivity, hormones, and others. The mechanisms of bacterial succession within the gastrointestinal tract, skin, and throat are complex and multifactorial. While the mechanism of microbial translocation in the lumen of the gastrointestinal tract is poorly understood and even contentious, our data will contribute to the dearth of information, at this center in particular and to the region as a whole, with regard to the clinical management of HIV-seropositive patients as well as plausible severe illnesses in HIV-seronegative individuals. The frequency of multidrug-resistant isolates in HIV-seropositive patients was higher than among the HIV-seronegative controls, which portends serious therapeutic options for these patients. The study of correlation analysis revealed only the bacteria load on the skin and the number of isolates on the throat of the HIV-seropositive patients was significantly influenced by the CD4 values. However, HIV-seropositive patients carried more pathogens probably due to immunosuppression that enhanced their unrestricted growth because of depression of both the innate and cell-mediated immunities. High CD4+ cell/mL count in a HIV-seropositive host correlates with low RNA copies/mm 3 [Figure 2]. Therefore, there is an urgent need for continuous monitoring of resistance patterns in bacteria in view of the increasing emergence of multidrug resistance among different bacterial populations. We faced some challenging limitations in the study. The patients did not follow through to completion and there was gender disparity. The number of participants at the baseline was 70 but by the third month, only 74.2% of the enrolled individuals showed up (52 out of 70) and by the sixth month, only half of the original number of participants showed up. Besides, this study was unintentionally gender inclined. More female than male participants enrolled voluntarily, even within the control population. Low male recruitment in HIV/AIDS studies were reported in other studies. [28],[29] Our findings, therefore, provide baseline data to institute effective therapeutic strategies in combating the challenges of antibiotic resistance among the immune-compromised. Hence, surveillance data, continuous antibiotic susceptibility testing in hospitals, and treatment regimens based on the history of previous antibiotics use as well as education of the population may lower the incidence of multidrug-resistant organisms.
Figure 2: CD4 cell count and RNA viral load values in randomly selected HIV-positive patients

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Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

 
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Correspondence Address:
Kwashie Ajibade Ako-Nai
Department of Microbiology, Faculty of Science, Obafemi Awolowo University, Ile Ife, Osun State
Nigeria
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/1755-6783.165844

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